US20080265078A1 - Tape reel, recording tape cartridge, take-up reel, pullout member, and drive device - Google Patents
Tape reel, recording tape cartridge, take-up reel, pullout member, and drive device Download PDFInfo
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- US20080265078A1 US20080265078A1 US12/109,891 US10989108A US2008265078A1 US 20080265078 A1 US20080265078 A1 US 20080265078A1 US 10989108 A US10989108 A US 10989108A US 2008265078 A1 US2008265078 A1 US 2008265078A1
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- hub
- recording tape
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- tape
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H75/00—Storing webs, tapes, or filamentary material, e.g. on reels
- B65H75/02—Cores, formers, supports, or holders for coiled, wound, or folded material, e.g. reels, spindles, bobbins, cop tubes, cans, mandrels or chucks
- B65H75/04—Kinds or types
- B65H75/08—Kinds or types of circular or polygonal cross-section
- B65H75/14—Kinds or types of circular or polygonal cross-section with two end flanges
- B65H75/148—Kinds or types of circular or polygonal cross-section with two end flanges with at least one frustoconical end flange
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H75/00—Storing webs, tapes, or filamentary material, e.g. on reels
- B65H75/02—Cores, formers, supports, or holders for coiled, wound, or folded material, e.g. reels, spindles, bobbins, cop tubes, cans, mandrels or chucks
- B65H75/18—Constructional details
- B65H75/28—Arrangements for positively securing ends of material
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B23/00—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
- G11B23/02—Containers; Storing means both adapted to cooperate with the recording or reproducing means
- G11B23/04—Magazines; Cassettes for webs or filaments
- G11B23/08—Magazines; Cassettes for webs or filaments for housing webs or filaments having two distinct ends
- G11B23/107—Magazines; Cassettes for webs or filaments for housing webs or filaments having two distinct ends using one reel or core, one end of the record carrier coming out of the magazine or cassette
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2701/00—Handled material; Storage means
- B65H2701/30—Handled filamentary material
- B65H2701/37—Tapes
- B65H2701/378—Recording tape
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2701/00—Handled material; Storage means
- B65H2701/50—Storage means for webs, tapes, or filamentary material
- B65H2701/51—Cores or reels characterised by the material
- B65H2701/515—Cores or reels characterised by the material assembled from parts made of different materials
Landscapes
- Storage Of Web-Like Or Filamentary Materials (AREA)
- Winding Of Webs (AREA)
Abstract
In a tape reel that includes a hub around which recording tape is wound and flanges disposed on both end portions of the hub, the elastic modulus in a radial direction of the hub is equal to or greater than 16.0 GPa, and the hub includes different radii on one end side thereof and another end side thereof. The recording tape is wound around the hub such that the side where the radius of curvature of the curvature of a tape edge of the recording tape is small corresponds to the small radius side of the hub. When the recording tape is wound around the hub, fluctuation of the recording tape in an axial direction of the hub is controlled, and one-layer protrusion and disorderly winding of the recording tape that has been wound around the hub are controlled.
Description
- This application claims priority under 35 USC 119 from Japanese Patent Application No. 2007-119574, the disclosure of which is incorporated by reference herein.
- 1. Field of the Invention
- The present invention relates to a tape reel and a take-up reel around which is wound recording tape such as magnetic tape used as a recording and playback medium mainly for computers and the like, a recording tape cartridge where the tape reel is housed inside a case, a pullout member that pulls out the recording tape from the tape reel inside the case, and a drive device into which the recording tape cartridge is loaded.
- 2. Description of the Related Art
- Conventionally, a recording tape cartridge has been known where recording tape such as magnetic tape used as a data recording and playback medium for computers and the like is wound around a reel and the reel is singly housed inside a case. When the recording tape cartridge is loaded into a drive device, the recording tape is pulled out via a leader member from an opening disposed in the recording tape cartridge. Then, the recording tape that has been pulled out is taken up onto a take-up reel that is disposed on the opposite side or the like of the recording tape cartridge, with tape guides and a recording and playback head being interposed between the take-up reel and the recording tape cartridge.
- Particularly in recording and playback systems (drive devices) that use recent recording tape cartridges whose recording density has been improved, a format where the recording and playback head is moved in a vertical direction by an actuator on the basis of servo signals that have been prerecorded on the recording tape and where the recording and playback head is caused to follow the servo signals and record and play back data signals is becoming mainstream. Consequently, it is desirable for the recording tape that has been pulled out from the recording tape cartridge to be supported by plural tape guides inside the drive device and to be controlled such that the recording tape always travels along a predetermined position of the recording and playback head.
- However, in actuality, phenomena such as so-called “one-layer protrusion” occur where, even though the recording tape is supported by tape guides, the recording tape fluctuates in an axial direction (vertical direction) of a hub (winding core portion) during travel, the recording tape that has been wound around the hub becomes disorderly wound, and a portion of the recording tape equal to one circling of the hub protrudes from a winding surface of the recording tape. In
FIG. 24 , there is shown a state of disorderly winding such as a step or one-layer protrusion from the winding surface of the recording tape (it will be noted that, inFIG. 24 , the winding surface of an upper tape edge of the recording tape is shown, so one-layer protrusion and the like from the winding surface of the recording tape is observed on a lower tape edge side of the recording tape). - When such disorderly winding fluctuates particularly in a short amount of time (when acceleration is large), there is the problem that the recording and playback head, which moves in the vertical direction on the basis of the servo signals that have been prerecorded on the recording tape, becomes unable to follow those abrupt fluctuations in the position of the recording tape and ends up becoming unable to record and play back desired data signals.
- Further, when servo tracking control is improved even more, the allowable amount of fluctuation in the width direction of the recording tape during travel inside the drive device—and particularly fluctuation at a high frequency (fluctuation in a short amount of time)—also becomes smaller. In other words, in high recording density recording and playback systems, it is foreseeable that, from this time forward, the size of the recording signals will become finer, the recording density will become higher, the size of the servo signals will become smaller, the recording density of the servo signals themselves will be improved, the servo tracking control system will become controlled at a high frequency, the traveling speed of the recording tape will become faster, and data signal recording and playback errors resulting from servo signal reading errors will occur even with fluctuations in the recording tape of a level that has thus far not been a problem.
- Meanwhile, causing the recording tape to travel along the inner surface of an upper flange of the hub by disposing a tapered angle of 0.01 degree to 0.1 degree in the hub and making the traveling reference of the recording tape to be on the side of the hub where the outer diameter is large (here, the upper side of the hub) has been disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2004-134060, for example. That is, in JP-A No. 2004-134060, there is disclosed that, when the hub has a tapered shape, the recording tape becomes wound around the hub toward the side of the hub where the outer diameter is large.
- However, recording tape has curvature (curvature in a width direction), this curvature of the recording tape affects the position where the recording tape is wound around the hub, and there are many instances where that affect is greater than the affect resulting from the hub being given a tapered shape. Consequently, when recording tape is wound around the hub described in JP-A No. 2004-134060, there is the potential for the recording tape to be taken up along the inner surface of a lower flange depending on the orientation of the curvature of the recording tape.
- In other words, even when the traveling reference of the recording tape is made to be on the upper flange side, there is the potential for the recording tape to end up traveling along the lower flange side. Further, when the amount of curvature of the recording tape is large, there is the danger for the recording tape to be caused to excessively move toward one of the flanges and for the tape edge to be strongly pushed against that flange and end up sustaining damage. That problem becomes pronounced particularly when the recording tape is made thinner. Further, when the recording tape is strongly pushed too much toward one of the flanges, there is also the danger for the one-layer protrusion phenomenon to occur because of a reaction triggered by this.
- Further, preventing disorderly winding of recording tape when the hub becomes deformed and the distance between the upper and lower flanges is gradually reduced in accompaniment with this deformation as the constricting force (coiling force) of the recording tape with respect to the hub increases is disclosed in JP-A No. 2002-251859, for example. However, the amount of the gradual reduction of the distance between the upper and lower flanges resulting from deformation of the hub changes also depending on the rigidity of the hub. Further, an instance where a tapered shape is imparted to the hub is not mentioned in JP-A No. 2002-251859.
- Moreover, that the winding shape (winding surface) is orderly (that orderly windability is improved) when the reel is made into one where the hub diameter on one end side of the outer peripheral surface of the hub becomes smaller with respect to the hub diameter on the other end side as the recording tape is wound around the hub is disclosed in JP-A No. 2004-310827. In this instance, the tapered amount of the hub increases in accompaniment with an increase in the winding amount of the recording tape around the hub, but ordinarily there are variations in the orientation of the curvature and the amount of curvature of the recording tape, so the traveling position of the recording tape with respect to the hub fluctuates and the winding shape (winding surface) of the recording tape onto the hub fluctuates. For that reason, in this reel, there is the danger for the orderly windability of the recording tape to be impaired and for this to promote tape edge damage.
- Thus, in view of the above-described circumstances, the present invention addresses obtaining a tape reel, a recording tape cartridge, a take-up reel, a pullout member and a drive device which, when recording tape has been wound around a hub, can control fluctuation of the recording tape in an axial direction of the hub, can control one-layer protrusion and disorderly winding of the recording tape that has been wound around the hub, can control problems that occur as a result of the one-layer protruding recording tape striking a flange, bending and sustaining tape edge damage when the recording tape cartridge receives a shock such as when the recording tape cartridge is dropped or the like, and can reduce servo signal reading errors and data signal recording and playback errors.
- A tape reel pertaining to a first aspect of the invention is provided by a tape reel including: a hub around which recording tape is wound; and flanges disposed on both end portions of the hub, wherein the elastic modulus in a radial direction of the hub is equal to or greater than 16.0 GPa, the hub includes different radii on one end side thereof and another end side thereof, and the recording tape is wound around the hub such that the side where the radius of curvature of the curvature of the tape edge of the recording tape is small corresponds to the small radius side of the hub.
- According to the first aspect of the invention, in a hub where a difference in radii is disposed on both end portions, the elastic modulus, i.e., a flexural modulus, in the radial direction of the hub is equal to or greater than 16.0 GPa, so the following actions (1) and (2) are provided, and the recording tape can be caused to move toward the flange on the small radius side of the hub and be wound around the hub because of the synergistic effects of (1) and (2). It will be noted that when the elastic modulus in the radial direction of the hub is equal to or greater than 19.2 GPa, this becomes more effective and is preferable.
- (1) When tension is applied in a direction substantially perpendicular with respect to the axial line of the hub and the recording tape is wound around the hub, the recording tape moves toward the flange on the small radius side of the hub because of the imbalance in the distribution of the surface pressure acting on the recording tape, and the recording tape is wound around the hub.
- (2) When the recording tape is wound around the hub such that the side where the radius of curvature of the curvature of the tape edge is small becomes the small radius side of the hub, the direction in which the recording tape moves becomes the small radius side of the hub.
- Thus, fluctuation of the recording tape in the axial direction of the hub (direction perpendicular with respect to the traveling direction of the recording tape) can be controlled, disorderly winding of the recording tape can be controlled, and orderly windability can be improved. Additionally, the occurrence of a step or one-layer or plural-layer protrusion from the winding surface of the recording tape that has been wound around the hub can be controlled, and problems that occur as a result of the one-layer protruding recording tape striking a flange, bending and sustaining tape edge damage when the recording tape cartridge receives a shock such as during transport or when the recording tape cartridge is dropped or during handling can be reduced.
- Further, the tape traveling position can be stabilized because the position of the recording tape can be controlled from fluctuating in the axial direction of the hub (direction perpendicular with respect to the traveling direction of the recording tape) even during travel of the recording tape inside the drive device. For this reason, servo signal reading errors and data signal recording and playback errors can be reduced even in high density recording, and a reduction of so-called position error signals and off-track can be expected.
- Further, in the tape reel of the first aspect of the invention, the ratio of the difference between the radius on the one end side of the hub and the radius on the other end side of the hub with respect to the width of the recording tape may be equal to or greater than 0.00039 and equal to or less than 0.00474.
- When the ratio of the difference between the radius on the one end side of the hub and the radius on the other end side of the hub with respect to the width of the recording tape is close to 0 (in the instance of a hub having a substantially circular cylinder shape), the effect of causing the recording tape that is wound around the hub to move toward the small radius side of the hub cannot be obtained. Further, when the ratio of the difference between the radius on the one end side of the hub and the radius on the other end side of the hub with respect to the width of the recording tape is too large, there is the danger for the recording tape to be pushed excessively toward the flange surface on the small radius side of the hub and sustain tape edge damage such that so-called radiation occurs, for the recording tape to interfere with the flange during travel and further sustain tape edge damage, and in addition for phenomena that develop into defects such as cinching to occur.
- For this reason, in the tape reel of the above-described configuration, the difference between the radius on the one end side of the hub and the radius on the other end side of the hub with respect to the width of the recording tape is identified. Specifically, the ratio of the difference between the radii is in the range of 0.00039 or greater and 0.00474 or less. Here, when the amount of curvature of the recording tape is small (e.g., 0.5 mm to 2.0 mm), the recording tape functions sufficiently in this range. However, from the standpoints of the productivity of the tape reel and design freedom, even when the amount of curvature of the recording tape is large (e.g., 2.5 mm), an excellent result can be obtained as long as the ratio of the difference between the radius on the one end side of the hub and the radius on the other end side of the hub with respect to the width of the recording tape is in the range of 0.00055 or greater and 0.00400 or less.
- In other words, when the ratio of the difference between the radius on the one end side of the hub and the radius on the other end side of the hub with respect to the width of the recording tape is in the range of 0.00055 or greater and 0.00400 or less, even when the radius of curvature of the curvature of the tape edge of the recording tape is small (even when the amount of curvature of the recording tape is large, such as 2.5 mm, for example), bad traveling phenomena such as tape edge damage and abnormal sounds resulting from the recording tape being excessively pushed toward the flange surface on the small radius side of the hub and interfering with the flange can be controlled. It will be noted that, although details of a measurement method will be described later, “amount of curvature” here means, using a line that interconnects both end portions of recording tape having a length of 1.0 mm as a reference line, the distance between that reference line and the center portion of the recording tape.
- Further, in the tape reel of the first aspect of the invention, the width of the recording tape may be substantially 12.65 mm, and the difference between the radius on the one end side of the hub and the radius on the other end side of the hub may be equal to or greater than 5 μm and equal to or less than 60 μm.
- When the difference between the radius on the one end side of the hub and the radius on the other end side of the hub is close to 0 (in the instance of a hub having a substantially circular cylinder shape), the effect of causing the recording tape that is wound around the hub to move toward the small radius side of the hub cannot be obtained. Further, when the difference between the radius on the one end side of the hub and the radius on the other end side of the hub is too large, there is the danger for the recording tape to be pushed excessively toward the flange surface on the small radius side of the hub and sustain tape edge damage such that so-called radiation occurs, for the recording tape to interfere with the flange during travel and further sustain tape edge damage, and in addition for phenomena that develop into defects such as cinching to occur.
- For this reason, in the tape reel of the above-described configuration, when the width of the recording tape is substantially 12.65 mm, the difference between the radius on the one end side of the hub and the radius on the other end side of the hub is equal to or greater than 5 μm and equal to or less than 60 μm. Here, when the amount of curvature of the recording tape is small (e.g., 0.5 mm to 2.0 mm), the recording tape functions sufficiently in this range. However, from the standpoints of the productivity of the tape reel and design freedom, even when the amount of curvature of the recording tape is large (e.g., 2.5 mm), an excellent result can be obtained as long as the difference between the radius on the one end side of the hub and the radius on the other end side of the hub is in the range of 7 μm or greater and 50 μm or less.
- In other words, when the width of the recording tape is substantially 12.65 mm, when the difference between the radius on the one end side of the hub and the radius on the other end side of the hub is in the range of 7 μm or greater and 50 μm or less, even when the radius of curvature of the curvature of the tape edge of the recording tape is small (even when the amount of curvature of the recording tape is large, such as 2.5 mm, for example), bad traveling phenomena such as tape edge damage and abnormal sounds resulting from the recording tape being excessively pushed toward the flange surface on the small radius side of the hub and interfering with the flange can be controlled.
- Further, in the tape reel of the above-described configuration, the absolute value of the amount of curvature of the recording tape may be equal to or greater than 0.15 mm and equal to or less than 2.5 mm.
- According to the tape reel of the above-described configuration, the absolute value of the amount of curvature of the recording tape is in the range of 0.15 mm or greater and 2.5 mm or less, so bad traveling phenomena such as tape edge damage and abnormal sounds resulting from the recording tape being excessively pushed toward the flange surface on the small radius side of the hub because of large curvature and interfering with the flange can be controlled. Further, ordinarily, when the curvature is in the vicinity of 0, it is easy for disorderly winding to occur as result of the polarity of the curvature value fluctuating, and the winding surface becomes a so-called rough winding state, but disorderly winding is controlled by making the absolute value of the amount of curvature equal to or greater than 0.15 mm and combining this with the aforementioned characteristic, and the winding surface becomes closer to orderly winding.
- In other words, instances where the recording tape sustains tape edge damage such that so-called radiation occurs, instances where the recording tape interferes with the flange on the small radius side of the hub during travel and further sustains tape edge damage, and in addition phenomena that develop into defects such as cinching can be prevented, and a tape traveling position that is appropriate and stable and a state where there is little disorderly winding can be achieved.
- It will be noted that when the absolute value of the curvature of the recording tape is in the range of 0.5 mm or greater and 2.0 mm or less, the moving of the tape edge toward the flange becomes appropriate when the recording tape has been wound around the hub, which is more preferable. In other words, there is less fluctuation in the position of the recording tape in the axial direction of the hub during travel, disorderly winding is controlled, and the recording tape is orderly wound in a state where it is along one of the upper and lower flanges, so tape edge damage is reduced in the recording tape.
- Further, in the tape reel of the first aspect of the invention, the hub may be configured to include a metal that is disposed integrally with a resin by insert molding or press-fitting.
- According to the tape reel of the above-described configuration, the rigidity of the hub can be easily raised in comparison to when the hub is formed by just a resin.
- Further, in the tape reel of the first aspect of the invention, the thickness of the recording tape may be equal to or less than 7.5 μm.
- When the thickness of the recording tape is thick, the rigidity of the recording tape also increases, so the strength of the tape edge increases, and it becomes difficult for problems such as tape edge damage to occur with respect also to pushing against the flanges, shock, friction, and wear. On the other hand, even with recording tapes of the same width, when the thickness of the recording tape becomes thin, the distribution of stress acting in the width direction of the recording tape also changes when the same tension is applied to the recording tape and the recording tape is wound around the hub. For this reason, in the tape reel of the above-described configuration, the thickness of the recording tape that is effective for application of the present invention is identified.
- Further, in the tape reel of the first aspect of the invention, the recording tape may include servo signals that become a positioning reference of a recording and playback head of a drive device, and the tape edge of the recording tape that has been wound around the hub that is on the side where the radius of an outer peripheral surface of the hub is small may serve as a servo tracking control reference during travel of the recording tape.
- According to the tape reel of the above-described configuration, the tape edge of the recording tape that is wound onto the hub that moves toward one of the flanges corresponds to the tape edge that is on the side that becomes the reference of servo tracking control during travel of the recording tape, so the tape traveling position of the recording tape can be stabilized. For this reason, servo tracking errors and data signal recording and playback errors can be reduced.
- Further, a recording tape cartridge pertaining to a second aspect of the invention is disposed with the tape reel of the first aspect of the invention and a case that rotatably houses the tape reel.
- According to the second aspect of the invention, effects that are substantially the same as the effects based on the first aspect of the invention can be obtained. In particular, there is a trend for recording tape to be made thin in order to increase the recording capacity of the recording tape per cartridge, whereby the rigidity of the recording tape drops and the strength of the tape edge drops, but because the rate of occurrence of one-layer protrusion from the winding surface of the recording tape and the amount of that protrusion can be controlled, it is difficult for the recording tape to sustain tape edge damage even when thin recording tape is used.
- Further, in the recording tape cartridge of the second aspect of the invention, the tape reel that is housed therein may be single.
- According to the recording tape cartridge of the above-described aspect, the orderly windability of the recording tape can be improved in the tape reel, and fluctuation of the position of the recording tape in the axial direction of the hub (direction perpendicular with respect to the traveling direction of the recording tape) during travel can be controlled, so fluctuation of the recording tape in the axial direction of the hub (direction perpendicular with respect to the traveling direction of the recording tape) in a take-up reel of a drive device that is difficult to make highly precise can be controlled by the tape reel of the recording tape cartridge. Consequently, this becomes suitable for a one-reel recording tape cartridge for backing up data of computers for which a high recording capacity is desired. It will be noted that the reason it is difficult to manufacture a take-up reel with high precision is because the shape of the take-up reel becomes complex because the take-up reel is disposed with the function of housing a pullout member inside the take-up reel.
- Further, a take-up reel of a third aspect of the invention is a take-up reel that is disposed inside a drive device and around which is wound recording tape that has been pulled out from a recording tape cartridge, the take-up reel comprising: a hub around which the recording tape is wound; and flanges disposed on both end portions of the hub, wherein the elastic modulus in a radial direction of the hub is equal to or greater than 16.0 GPa, the hub includes different radii on one end side thereof and another end side thereof, and the side where the radius of curvature of the curvature of a tape edge of the recording tape is small is wound around the small radius side of the hub.
- In the take-up reel of the third aspect of the invention, effects that are substantially the same as the effects based on the first aspect of the invention can be obtained. That is, according to the third aspect of the invention, in a hub where a difference in radii is disposed on both end portions, the elastic modulus in the radial direction of the hub is equal to or greater than 16.0 GPa, so the following actions (1) and (2) are provided, and the recording tape can be caused to move toward the flange on the small radius side of the hub and be wound around the hub because of the synergistic effects of (1) and (2). It will be noted that when the elastic modulus in the radial direction of the hub is equal to or greater than 19.2 GPa, this becomes more effective and is preferable.
- (1) When tension is applied in a direction substantially perpendicular with respect to the axial line of the hub and the recording tape is wound around the hub, the recording tape moves toward the flange on the small radius side of the hub because of the imbalance in the distribution of the surface pressure acting on the recording tape, and the recording tape is wound around the hub.
- (2) When the recording tape is wound around the hub such that the side where the radius of curvature of the curvature of the tape edge is small becomes the small radius side of the hub, the direction in which the recording tape moves becomes the small radius side of the hub.
- Thus, the position of the recording tape can be controlled from fluctuating in the axial direction of the hub (direction perpendicular with respect to the traveling direction of the recording tape) during travel of the recording tape inside the drive device, and the traveling position of the recording tape can be stabilized. Consequently, disorderly winding of the recording tape can be controlled, orderly windability can be improved, and the occurrence of a step or one-layer or plural-layer protrusion from the winding surface of the recording tape that has been wound around the hub can be controlled.
- Further, servo signal reading errors and data signal recording and playback errors can be reduced resulting from the recording and playback head can be reduced even in high density recording, and a reduction of so-called position error signals and off-track can be expected. Further, tape edge damage that occurs during travel of the recording tape because of excessive contact with tape guides disposed in the drive device, the flanges of the take-up reel, and the flanges of the tape reel can be prevented.
- Further, in the take-up reel of the third aspect of the invention, the ratio of the difference between the radius on the one end side of the hub and the radius on the other end side of the hub with respect to the width of the recording tape that is wound around the hub may be equal to or greater than 0.00039 and equal to or less than 0.00474.
- According to the take-up reel of the above-described configuration, effects that are substantially the same as effects resulting from tape reel having the same configuration can be obtained. That is, when the ratio of the difference between the radius on the one end side of the hub and the radius on the other end side of the hub with respect to the width of the recording tape that is wound around the hub is close to 0 (in the instance of a hub having a substantially circular cylinder shape), the effect of causing the recording tape that is wound around the hub to move toward the small radius side of the hub cannot be obtained.
- Further, when the ratio of the difference between the radius on the one end side of the hub and the radius on the other end side of the hub with respect to the width of the recording tape that is wound around the hub is too large, there is the danger for the recording tape to be pushed excessively toward the flange surface on the small radius side of the hub and sustain tape edge damage such that so-called radiation occurs, for the recording tape to interfere with the flange during travel and further sustain tape edge damage, and in addition for phenomena that develop into defects such as cinching to occur.
- For this reason, in the take-up reel of the above-described configuration, the difference between the radius on the one end side of the hub and the radius on the other end side of the hub with respect to the width of the recording tape that is wound around the hub is identified. Specifically, the ratio of the difference between the radii is in the range of 0.00039 or greater and 0.00474 or less. Here, when the amount of curvature of the recording tape is small (e.g., 0.5 mm to 2.0 mm), the recording tape functions sufficiently in this range. However, from the standpoints of the productivity of the tape reel and design freedom, even when the amount of curvature of the recording tape is large (e.g., 2.5 mm), an excellent result can be obtained as long as the ratio of the difference between the radius on the one end side of the hub and the radius on the other end side of the hub with respect to the width of the recording tape is in the range of 0.00055 or greater and 0.00400 or less.
- In other words, when the ratio of the difference between the radius on the one end side of the hub and the radius on the other end side of the hub with respect to the width of the recording tape is in the range of 0.00055 or greater and 0.00400 or less, even when the radius of curvature of the curvature of the tape edge of the recording tape is small (even when the amount of curvature of the recording tape is large, such as 2.5 mm, for example), bad traveling phenomena such as tape edge damage and abnormal sounds resulting from the recording tape being excessively pushed toward the flange surface on the small radius side of the hub and interfering with the flange can be controlled. It will be noted that, although details of a measurement method will be described later, the “amount of curvature” mentioned here means, using a line that interconnects both end portions of recording tape having a length of 1.0 mm as a reference line, the distance between that reference line and the center portion of the recording tape.
- Further, in the take-up reel of the third aspect of the invention, the width of the recording tape that is wound around the hub may be substantially 12.65 mm, and the difference between the radius on the one end side of the hub and the radius on the other end side of the hub may be equal to or greater than 5 μm and equal to or less than 60 μm.
- In the take-up reel of the above-described configuration, effects that are substantially the same as effects resulting from a tape reel having the same configuration can be obtained. That is, when the difference between the radius on the one end side of the hub and the radius on the other end side of the hub is close to 0 (in the instance of a hub having a substantially circular cylinder shape), the effect of causing the recording tape that is wound around the hub to move toward the small radius side of the hub cannot be obtained.
- Further, when the difference between the radius on the one end side of the hub and the radius on the other end side of the hub is too large, there is the danger for the recording tape that is wound around the hub to be pushed excessively toward the flange surface on the small radius side of the hub and sustain tape edge damage such that so-called radiation occurs, for the recording tape to interfere with the flange during travel and further sustain tape edge damage, and in addition for phenomena that develop into defects such as cinching to occur.
- For this reason, in the take-up reel of the above-described configuration, when the width of the recording tape is substantially 12.65 mm, the difference between the radius on the one end side of the hub and the radius on the other end side of the hub is equal to or greater than 5 μm and equal to or less than 60 μm. Here, when the amount of curvature of the recording tape is small (e.g., 0.5 mm to 2.0 mm), the recording tape functions sufficiently in this range. However, from the standpoints of the productivity of the tape reel and design freedom, even when the amount of curvature of the recording tape is large (e.g., 2.5 mm), an excellent result can be obtained as long as the difference between the radius on the one end side of the hub and the radius on the other end side of the hub is in the range of 7 μm or greater and 50 μm or less.
- In other words, when the width of the recording tape is substantially 12.65 mm, when the difference between the radius on the one end side of the hub and the radius on the other end side of the hub is in the range of 7 μm or greater and 50 μm or less, even when the radius of curvature of the curvature of the tape edge of the recording tape is small (even when the amount of curvature of the recording tape is large, such as 2.5 mm, for example), bad traveling phenomena such as tape edge damage and abnormal sounds resulting from the recording tape being excessively pushed toward the flange surface on the small radius side of the hub and interfering with the flange can be controlled.
- Further, in the take-up reel of the third aspect of the invention, the absolute value of the amount of curvature of the recording tape that is wound around the hub may be equal to or greater than 0.15 mm and equal to or less than 2.5 mm.
- According to the take-up reel of the above-described configuration, effects that are substantially the same as effects resulting from a tape reel having the same configuration can be obtained. That is, the absolute value of the amount of curvature of the recording tape is in the range of 0.15 mm or greater and 2.5 mm or less, so bad traveling phenomena such as tape edge damage and abnormal sounds resulting from the recording tape being excessively pushed toward the flange surface on the small radius side of the hub because of large curvature and interfering with the flange can be controlled. Further, ordinarily, when the curvature is in the vicinity of 0, it is easy for disorderly winding to occur as result of the polarity of the curvature value fluctuating, and the winding surface becomes a so-called rough winding state, but disorderly winding is controlled by making the absolute value of the amount of curvature equal to or greater than 0.15 mm and combining this with the aforementioned characteristic, and the winding surface becomes closer to orderly winding.
- In other words, instances where the recording tape sustains tape edge damage such that so-called radiation occurs, instances where the recording tape interferes with the flange on the small radius side of the hub during travel and further sustains tape edge damage, and in addition phenomena that develop into defects such as cinching can be prevented, and a tape traveling position that is appropriate and stable and a state where there is little disorderly winding can be achieved.
- It will be noted that when the absolute value of the curvature of the recording tape is in the range of 0.5 mm or greater and 2.0 mm or less, the moving of the tape edge toward the flange becomes appropriate when the recording tape has been wound around the hub, which is more preferable. In other words, there is less fluctuation in the position of the recording tape in the axial direction of the hub during travel, disorderly winding is controlled, and the recording tape is orderly wound in a state where it is along one of the upper and lower flanges, so tape edge damage is reduced in the recording tape.
- Further, in the take-up reel of the third aspect of the invention, the hub may be configured to include a metal that is disposed integrally with a resin by insert molding or press-fitting.
- According to the take-up reel of the above-described configuration, effects that are substantially the same as effects resulting from a tape reel having the same configuration can be obtained. That is, the rigidity of the hub can be easily raised in comparison to when the hub is formed by just a resin.
- Further, in the take-up reel of the third aspect of the invention, the thickness of the recording tape that is wound around the hub may be equal to or less than 7.5 μm.
- According to the take-up reel of the above-described configuration, effects that are substantially the same as effects resulting from a tape reel having the same configuration can be obtained. That is, when the thickness of the recording tape is thick, the rigidity of the recording tape also increases, so the strength of the tape edge increases, and it becomes difficult for problems such as tape edge damage to occur with respect also to pushing against the flanges, shock, friction, and wear. On the other hand, even with recording tapes of the same width, when the thickness of the recording tape becomes thin, the distribution of stress acting in the width direction of the recording tape also changes when the same tension is applied to the recording tape and the recording tape is wound around the hub. For this reason, in the take-up reel of the above-described configuration, the thickness of the recording tape that is effective for application of the present invention is identified.
- Further, in the take-up reel of the third aspect of the invention, the recording tape that is wound around the hub may include servo signals that become a positioning reference of a recording and playback head of a drive device, and the tape edge of the recording tape that has been wound around the hub that is on the side where the radius of an outer peripheral surface of the hub is small may serve as a servo tracking control reference during travel of the recording tape.
- According to the take-up reel of the above-described configuration, effects that are substantially the same as effects resulting from a tape reel having the same configuration can be obtained. That is, the tape edge of the recording tape that is wound onto the hub that moves toward one of the flanges corresponds to the tape edge that is on the side that becomes the reference of servo tracking control during travel of the recording tape, so the tape traveling position of the recording tape can be stabilized. For this reason, servo tracking errors and data signal recording and playback errors can be reduced.
- Further, a pullout member of a fourth aspect of the invention is a pullout member that pulls out recording tape from a recording tape cartridge, is housed in the hub of the take-up reel of the third aspect, and is disposed with a take-up surface that configures part of an outer peripheral surface of the hub, wherein the elastic modulus of the take-up surface is equal to or greater than 16.0 GPa, the take-up surface includes different radii on one end side thereof and another end side thereof, and the take-up surface and the outer peripheral surface of the hub become substantially even in a state where the pullout member is housed in the hub.
- When recording tape is wound around the hub of the take-up reel when there is a step between the take-up surface of the pullout member and the outer peripheral surface of the hub, the potential for so-called “projection” to occur because of this step and for dropout to arise at that portion and lead to an error becomes greater. However, according to the pullout member of the above-described configuration, the radius on the one end side and the radius on the other end side of the take-up surface of the pullout member that configures part of the outer peripheral surface of the hub of the take-up reel are made different, and it is ensured that the take-up surface of the pullout member and the outer peripheral surface of the hub become substantially even in a state where the pullout member is housed in the hub, so such a step does not arise across the entire outer peripheral surface of the hub. For this reason, effects that are substantially the same as effects resulting from a take-up reel having the same configuration can be obtained.
- Further, a drive device of a fifth aspect of the invention includes the take-up reel of the third aspect of the invention around which is wound recording tape that has been pulled out from a recording tape cartridge that has been loaded into the drive device.
- According to the fifth aspect of the invention, in the drive device, effects that are substantially the same as effects resulting from a take-up reel having the same configuration can be obtained. That is, the position of the recording tape can be controlled from fluctuating in the axial direction of the hub during travel of the recording tape inside the drive device, and the tape traveling position can be stabilized. For this reason, servo signal reading errors and data signal recording and playback errors resulting from the recording and playback head can be reduced even in high density recording, and a reduction of so-called position error signals and off-track can be expected.
- Further, tape edge damage that occurs because of excessive contact with tape guides disposed in the drive device, the flanges of the take-up reel, and the flanges of the tape reel can be prevented. In other words, instances where so-called radiation occurs because of tape edge damage, instances where the recording tape interferes with the flanges during travel and further sustains tape edge damage, and in addition phenomena that develop into defects such as cinching can be prevented, and a tape traveling position that is appropriate and stable and a state where there is little disorderly winding can be achieved.
- Further, the drive device of the fifth aspect of the invention may include the pullout member of the fourth aspect of the invention.
- According to the drive device of the above-described configuration, in the drive device, effects that are substantially the same as effects resulting from a pullout member having the same configuration can be obtained. That is, the radius on the one end side and the radius on the other end side of the take-up surface of the pullout member that configures part of the outer peripheral surface of the hub of the take-up reel are made different, and it is ensured that the take-up surface of the pullout member and the outer peripheral surface of the hub become substantially even in a state where the pullout member is housed in the hub, so a step does not arise across the entire outer peripheral surface of the hub. For this reason, it is difficult for “projection”, which occurs when the recording tape has been wound around the hub of the take-up reel when there is a step, to occur.
- As described above, according to the present invention, when recording tape has been wound around a hub, fluctuation of the recording tape in an axial direction of the hub can be controlled, and one-layer protrusion and disorderly winding of the recording tape that has been wound around the hub can be controlled. Consequently, problems that occur as a result of the one-layer protruding recording tape striking a flange, bending and sustaining tape edge damage when the recording tape cartridge receives a shock such as when the recording tape cartridge is dropped or the like can be reduced, and the occurrence of servo signal reading errors and data signal recording and playback errors can be reduced.
-
FIG. 1 is a general perspective view of a recording tape cartridge pertaining to an embodiment of the present invention; -
FIG. 2 is a general exploded perspective view of the recording tape cartridge pertaining to the embodiment of the present invention; -
FIG. 3 is a general side sectional view of a reel pertaining to the embodiment of the present invention; -
FIG. 4 is a general plan view of a reel hub; -
FIG. 5 is a general plan view of a drive device after the recording tape cartridge has been loaded into the drive device; -
FIG. 6 is a general side view of the drive device after the recording tape cartridge has been loaded into the drive device; -
FIG. 7A andFIG. 7B are general perspective views showing the configuration of a pullout member of a take-up reel; -
FIG. 8 is a general side view showing servo signals of recording tape; -
FIG. 9A is a general side view showing a state where the recording tape is wound around the reel, andFIG. 9B is a general side view describing the action of the reel; -
FIG. 10 is a general perspective view for describing a method of measuring radii of the reel; -
FIG. 11 is a general perspective view showing a tape shape measuring device that measures the amount of curvature of the recording tape; -
FIG. 12A andFIG. 12B are general side views describing the action of the tape shape measuring device; -
FIG. 13 is a general perspective view showing an optical measuring device that is used for measuring the amount of curvature of the recording tape; -
FIG. 14 is a general plan view showing a method of measuring the amount of curvature of positive curvature recording tape; -
FIG. 15 is a general plan view showing negative curvature of the recording tape; -
FIG. 16A is a winding form measurement chart of negative curvature recording tape, andFIG. 16B is a winding form measurement chart of positive curvature recording tape; -
FIG. 17 is a general exploded sectional view of a reel where deformation of a reel hub and upper and lower flanges does not associatively act on/affect each of them; -
FIG. 18 is a general side sectional view of the reel where deformation of the reel hub and the upper and lower flanges does not associatively act on/affect each of them; -
FIG. 19 is a general side sectional view of a reel where deformation of a reel hub and upper and lower flanges associatively acts on/affects each of them; -
FIG. 20 is a winding form measurement chart in an instance where negative curvature recording tape T is wound around a reel with a dependent structure where the material of the reel hub is PC and the difference between the radii of the reel hub is −0.003 mm; -
FIG. 21 is a winding form measurement chart in an instance where positive curvature recording tape T is wound around a reel with a dependent structure where the material of the reel hub is Al and the difference between the radii of the reel hub is +0.040 mm; -
FIG. 22 is a winding form measurement chart in an instance where negative curvature recording tape T is wound around a reel with an independent structure where the material of the reel hub is PC and the difference between the radii of the reel hub is +0.002 mm; -
FIG. 23 is a winding form measurement chart in an instance where negative curvature recording tape T is wound around a reel with an independent structure where the material of the reel hub is Al and the difference between the radii of the reel hub is −0.043 mm; and -
FIG. 24 is a winding form measurement chart when negative curvature recording tape is wound around a conventional reel. - Below, the best mode for implementing the present invention will be described in detail on the basis of an embodiment shown in the drawings. For the convenience of description, in
FIG. 1 , arrow A represents the direction in which arecording tape cartridge 10 is loaded into a drive device 70 (seeFIG. 5 ) and will be referred to as a front direction (front side) of therecording tape cartridge 10. Additionally, the direction of arrow B, which is orthogonal to arrow A, will be referred to as a right direction (right side). Further, the direction of arrow C represents a width direction in the present embodiment and will be referred to as a vertical direction, a height direction, and an axial direction of a reel 20 (a reel hub 22) and a take-up reel 80 (a reel hub 82). - As shown in
FIG. 1 toFIG. 3 , therecording tape cartridge 10 includes a substantially rectangular box-shapedcase 12. Thecase 12 includes anupper case 14 and alower case 16 that are made of a resin such as polycarbonate (PC). Theupper case 14 is configured by atop plate 14A and aperipheral wall 14B that is disposed upright along the peripheral edge of thetop plate 14A. Thelower case 16 is configured by abottom plate 16A and aperipheral wall 16B that is disposed upright along the peripheral edge of thebottom plate 16A. Thecase 12 is configured as a result of theupper case 14 and thelower case 16 being joined together by ultrasonic welding or screwing in a state where theperipheral wall 14B and theperipheral wall 16B have been brought into contact with each other. - Just one reel (tape reel) 20 is rotatably housed inside the
case 12. Thereel 20 is configured by a bottomed circular cylinder-shapedreel hub 22 that configures an axial center portion (winding core portion) of thereel 20, alower flange 26 that is integrally molded with the lower end portion of thereel hub 22, and anupper flange 24 that is ultrasonically welded to and integrated with the upper end portion of thereel hub 22. Ametal ring 22B that has a circular cylinder shape and is made of aluminium, for example, is integrally fixedly attached by insert molding to the inner peripheral surface side of aresin portion 22A that configures thereel hub 22. Additionally, a flexural modulus (elastic modulus, modulus of elasticity) E in the radial direction of thereel hub 22 is equal to or greater than 16.0 GPa and preferably equal to or greater than 19.2 GPa. - Here, as shown in
FIG. 4 , assuming that a represents the thickness of theresin portion 22A that configures thereel hub 22, that Ea represents the flexural modulus of the resin material of theresin portion 22, that b represents the thickness of themetal ring 22B that configures thereel hub 22, and that Eb represents the flexural modulus of the metal material of themetal ring 22B, then the flexural modulus E in the radial direction of thereel hub 22 is determined by: E=Ea×a/(a+b)+Eb×b/(a+b). It will be noted that the flexural modulus Eb of themetal ring 22B is equal to or greater than the flexural modulus Ea of theresin portion 22A. - Further, the values 16.0 GPa and 19.2 GPa are based on the results of Table 1 below. That is, the values of the flexural modulus E of example 3 and example 4 of Table 1 are lower limit values calculated assuming that variations and error are included by 5% in the values of the original flexural moduli Ea and Eb. Consequently, when 5% error is removed from these values, the values become the above-described numerical values. Further, in Table 1, evaluations in regard to whether or not the winding form of recording tape T is good or bad are also shown. Here, example 1 is an instance where the
reel hub 22 is formed by just theresin portion 22A, and example 2 is an instance where thereel hub 22 is formed by just themetal ring 22B. -
TABLE 1 Elastic Modulus Elastic Modulus Elastic of Resin Portion of Resin Portion Modulus of Thickness a Thickness b when Thickness when Thickness Reel Hub; E Winding Example (mm) (mm) is a; Ea (GPa) is b; Eb (GPa) (GPa) Shape* 1 2.5 — 3.6 — 3.6 to □ 2 — 2.5 — 70.0 70.0 ∘ 3 2.0 0.5 3.6 70.0 16.9 □ 4 1.5 0.5 3.6 70.0 20.2 □ to ∘ 5 1.0 1.0 3.6 70.0 36.8 □ to ∘ *∘ = extremely good; □ = good; = somewhat bad; x =P9 bad - Further, as shown in
FIG. 3 , the reel hub 22 (theresin portion 22A) is formed such that, when seen in a side sectional view, the radius of the outer peripheral surface of the reel hub 22 (theresin portion 22A) on theupper flange 24 side is larger than the radius of the outer peripheral surface of the reel hub 22 (theresin portion 22A) on thelower flange 26 side, and a difference ΔR between the radius of thereel hub 22 on theupper flange 24 side and the radius of thereel hub 22 on thelower flange 26 side is in the range of 5 μm to 60 μm. That is, the ratio of the difference ΔR between the radius of thereel hub 22 on theupper flange 24 side and the radius of thereel hub 22 on thelower flange 26 side is in the range of 0.00039 to 0.00474 with respect to the width of the recording tape T (here, ½ inch width, substantially 12.65 mm). - Here, a method of measuring the radii of the outer peripheral surface of the
reel hub 22 will be described. As shown inFIG. 10 , a chucking portion (a later-described reel gear 44) of thereel 20 that chucks with thedrive device 70 is placed face down, and thereel 20 is set on an unillustrated master chucking gear (a high-precision reference gear). Then, in this state, the outer shape of thereel hub 22 is measured from its lower end portion side to its upper end portion side by atouch sensor probe 90 of a contact-type three-dimensional measuring machine. - It will be noted that, at this time, a hypothetical center (axial center) when measuring the radii of the
reel hub 22 is the center (axial center) of the master chucking gear. Moreover, as for the positions of the upper end portion and the lower end portion of the measurement position, because thetouch sensor probe 90, which has a diameter of 1 mm, is used, the center position thereof is set to be in the range of 0.7 mm to 1.0 mm from the upper end portion and the lower end portion of thereel hub 22 during measurement so as to not interfere with theupper flange 24 or thelower flange 26. Additionally, the measurement points of thetouch sensor probe 90 are set in substantially equidistant intervals such that the number of measurement points is at least ten in total. This measurement is similarly performed at six places every 60 degrees. - From this result, the difference ΔR between the radius of the
reel hub 22 on theupper flange 24 side and the radius of thereel hub 22 on thelower flange 26 side is calculated thusly: ΔR=ΔRmax−(ΔRmax−ΔRmin)/2=(ΔRmax+ΔRmin)/2. It will be noted that ΔRmax is a maximum value of ΔR1 to ΔR6 and that ΔRmin is a minimum value of ΔR1 to ΔR6. Further, ΔR1 to ΔR6 are radius values (n=1 to 6) equal to the radius value of the large radius side (theupper flange 24 side) of thereel hub 22 minus the small radius side (thelower flange 26 side) of thereel hub 22 at positions of six places every 60 degrees. - Further, because it suffices as long as the radii of the
reel hub 22 are different between theupper flange 24 side and thelower flange 26 side in the outer shape of thereel hub 22, the outer peripheral surface of thereel hub 22 does not have to have a tapered shape where its upper side and its lower side are interconnected by a straight line when seen from the side. In other words, it is alright if there are fine concavo-convexities in the outer peripheral surface of thereel hub 22, and the outer peripheral surface of thereel hub 22 may have a shape where its upper side and its lower side are interconnected by a curved line when seen from the side. Moreover, the outer peripheral surface of thereel hub 22 may be curved when seen from the side, or part of the outer peripheral surface of thereel hub 22 may be parallel to the axial line of thereel hub 22. - Recording tape T such as magnetic tape serving as an information recording and playback medium is wound around the outer peripheral surface of the
reel hub 22 of thereel 20 with a predetermined coiling force (tension) F (e.g., F=0.588 N to 0.980 N), and the fluctuation width in the width direction of the recording tape T that has been wound around thereel hub 22 is controlled by theupper flange 24 and thelower flange 26. It will be noted that the mutually opposing surfaces of theupper flange 24 and thelower flange 26 are formed as taperedsurfaces FIG. 3 ) where the distance between the flanges gradually increases toward the outer side (outer peripheral edge side). Further, in order to increase the recording capacity of the recording tape T, the thickness of the recording tape T is equal to or less than 7.5 μm and preferably equal to or less than 6.9 μm. - Further, ordinarily the recording tape T curves in its width direction (in the upper direction or the lower direction). In the present embodiment, when the recording tape T is seen with its upper edge TA facing up, curvature where the recording tape T curves upward will be referred to as negative curvature, and curvature where the recording tape T curves downward will be referred to as positive curvature. Consequently, the recording tape T shown in
FIG. 14 is positive curvature recording tape T because its upper edge TA curves upward, and the recording tape T shown inFIG. 15 is negative curvature recording tape T because its upper edge TA curves upward. In thereel 20 of the present embodiment, as described later, positive curvature recording tape T is wound around thereel hub 22, and the amount of curvature ΔD of the positive curvature recording tape T is in the range of 0.15 mm to 2.5 mm. - Here, “amount of curvature ΔD” means, using a line that interconnects both end portions of recording tape T that has a length of 1.0 mm as a reference line, the distance between that reference line and the center portion of the recording tape T. Next, a method of measuring the amount of curvature ΔD of the recording tape T will be described. In
FIG. 11 , there is shown a tapeshape measuring device 100. A substantially rectangular parallelepiped-shapedelectrostatic attraction base 102 is disposed in the tapeshape measuring device 100, and aguide member 104 is disposed on the upper portion of theelectrostatic attraction base 102. - As shown in
FIG. 12A andFIG. 12B , theguide member 104 is configured so as to be horizontally movable over the upper portion of theelectrostatic attraction base 102 and along the longitudinal direction of theelectrostatic attraction base 102 in a state where a clearance is disposed between theguide member 104 and the upper surface (anattraction surface 102A) of theelectrostatic attraction base 102. The recording tape T, which has been precut to a length of the prescribed 1 m to which leeway has been added to both ends, is placed on theattraction surface 102A of theelectrostatic attraction base 102 so as to cover the upper surface of theguide member 104. Then, both end sides of the recording tape T are freed in a state where there is leeway in the length, and air is blown onto the recording tape T by anozzle 108. - Then, with the air being blown onto the recording tape T, the
guide member 104 and thenozzle 108 slide (move) at a predetermined speed along theattraction surface 102A. Thus, the recording tape T separates from the top of theattraction surface 102A and is again guided onto theattraction surface 102A in a state where excess force has been removed. - Further, as shown in
FIG. 13 , plural electrode pairs 110 are disposed along the longitudinal direction in theelectrostatic attraction base 102. As the recording tape T is guided to theattraction surface 102A, switches of the electrode pairs 110 corresponding to the recording tape T that has been guided on theattraction surface 102A are sequentially actuated, and theattraction surface 102A sequentially charges the recording tape T in correspondence to the guiding of the recording tape T. Thus, the recording tape T carries electrostatic electricity (an electrical charge) and is sequentially attracted to theattraction surface 102A by that electrostatic attraction. - Then, the air blown from the
nozzle 108 pushes the attracted recording tape T with a predetermined pressure. In this manner, when the recording tape T is pushed with the predetermined pressure, air present between the recording tape T and theattraction surface 102A is pushed out in accompaniment with theattraction surface 102A and the undersurface of the recording tape T. Consequently, the recording tape T can excellently be brought into tight contact with theattraction surface 102A. - Next, the shape of the recording tape T attracted to the
attraction surface 102A is measured by anoptical measuring device 112.Transparent portions 116 through which laser light L emitted from alaser generator 114 of theoptical measuring device 112 is passable are disposed in theelectrostatic attraction base 102. In a state where the recording tape T is attracted to theattraction surface 102A, thetransparent portions 16 are irradiated with the laser light L, and the laser light L transmitted through thetransparent portions 16 is received by a laseroptical receiver 118 disposed below theelectrostatic attraction base 102. Thus, the position of the edge of the recording tape T becomes measurable. - Specifically, as shown in
FIG. 14 , the laser light L, which is band-like in the width direction, is emitted from thelaser generator 114 disposed on the upper side of measurement points A, B and C such that the laser light L straddles a reference line AC that interconnects the measurement point A and the measurement point C. Then, the laser light L that has been transmitted through thetransparent portions 116 is received by the laseroptical receiver 118 disposed below theelectrostatic attraction base 102—that is, on the lower side of the measurement points A, B and C. At this time, when the recording tape T is curved, the received amount of the laser light L that is band-like in the width direction (the length in the width direction of the laser light L that has been transmitted) becomes smaller. - Next, the length in the width direction of the laser light L that has been transmitted is measured by the laser
optical receiver 118 to determine the positions of the measurement points A, B and C (the position of the upper edge TA). Then, the distance between the reference line AC and the measurement point B—that is, an amount of displacement (ΔD)—is calculated on the basis of the positions of the measurement points A, B and C, and the value that has been calculated becomes the amount of curvature at the measurement point B. Here, that the length of the reference line AC is 1.0 m is prescribed in JIS X6175. - Then, as shown in
FIG. 14 , it is regarded that the polarity of the recording tape T is positive curvature in an instance where the side where the radius of curvature of the curvature of the tape edge of the recording tape T is small is on the lower side that is shown—that is, an instance where the reference line AC is covered by the recording tape T—and, as shown inFIG. 15 (FIG. 15 is a diagram whereFIG. 14 has been simplified), it is regarded that the polarity of the recording tape T is negative curvature in an instance where the side where the radius of curvature of the curvature of the tape edge of the recording tape T is on the upper side that is shown—that is, an instance where a clearance δ arises between the reference line AC and the upper side of the tape edge of the recording tape T (the so-called upper edge TA). It will be noted that in a state where the recording tape T has been wound around thereel hub 22, this upper edge TA side is on theupper flange 24 side of thereel hub 22. - As shown in
FIG. 2 , a reel gear 44 (seeFIG. 3 ) is annularly formed on the undersurface of abottom wall 28 of thelower flange 26, and agear opening 40 for exposing thereel gear 44 to the outside is disposed in the center portion of thelower case 16. Thereel gear 44 exposed from thegear opening 40 meshes with, and is driven to rotate by, a drive gear (not shown) of the drive device 70 (seeFIG. 5 ), whereby thereel 20 is made capable of relative rotation with respect to thecase 12 inside thecase 12. - Further, an annular reel plate 46 (see
FIG. 3 ) comprising a magnetic material is fixedly attached, by insert molding or the like, to the undersurface of thebottom wall 28 on the radial direction inner side of thereel gear 44. Thereel plate 46 is configured to be attracted to and held by the magnetic force of an annular magnet (not shown) disposed in thedrive device 70. Moreover, as shown inFIG. 2 , thereel 20 is held, such that it does not rattle, by a freeplay limiting wall 42 that is partially disposed on, so as to project from, the inner surfaces of theupper case 14 and thelower case 16 and which serves as an inner wall on a circular locus coaxial with thegear opening 40. - Further, as shown in
FIG. 1 andFIG. 2 , anopening 18 for allowing the recording tape T wound onto thereel 20 to be pulled out is formed in aright wall 12B of thecase 12. Aleader pin 30 that is pulled out by, while being locked to (gripped), a leader block 85 (seeFIG. 7A ) that is a pullout member of thedrive device 70 is fixedly attached to a free end portion of the recording tape T pulled out from theopening 18.Annular grooves 32 are formed in both end portions of theleader pin 30 that project from the width direction edges of the recording tape T, and theannular grooves 32 are locked byhooks 85A of the leader block 85 (seeFIG. 7B ). - Further, a pair of upper and lower
pin holding portions 36 that position and hold theleader pin 30 inside thecase 12 are disposed inside theopening 18 in thecase 12—that is, in the inner surface of thetop plate 14A of theupper case 14 and in the inner surface of thebottom plate 16A of thelower case 16. Thepin holding portions 36 have substantially semicircular shapes whose sides in the direction in which the recording tape T is pulled out are open, and both endportions 34 of theleader pin 30 in an upright state are capable of entering and exiting thepin holding portions 36 from the open sides thereof. - Further, a
plate spring 38 is fixedly disposed in the vicinity of thepin holding portions 36. Two-pronged distal end portions of theplate spring 38 respectively engage with both the upper andlower end portions 34 of theleader pin 30 and hold theleader pin 30 in thepin holding portions 36. It will be noted that when theleader pin 30 enters and exits thepin holding portions 36, the distal end portions of theplate spring 38 appropriately elastically deform to allow movement of theleader pin 30. - Further, the
opening 18 is opened and closed by adoor 50. Thedoor 50 is formed in a substantially rectangular plate-like shape of a size capable of blocking theopening 18, andgroove portions 64 that allow the upper and lower end portions of thedoor 50 to slidably fit therein are formed in thetop plate 14A and thebottom plate 16A inside theopening 18 so that thedoor 50 can move along theright wall 12B of thecase 12. - Further, a
shaft 52 is disposed on, so as to project from, the center of the rear end portion of thedoor 50, and acoil spring 58 is fitted over theshaft 52. Additionally, anenlarged portion 54 that prevents thecoil spring 58 from coming off is formed on the rear end of theshaft 52. Further, a support table 60 including a lockingportion 62 that locks the rear end of thecoil spring 58 fitted over theshaft 52 is disposed on, so as to project from, thelower case 16. - Consequently, the
shaft 52 is slidably supported on the support table 60 and the rear end of thecoil spring 58 is locked by the lockingportion 62, whereby thedoor 50 is always biased by the biasing force of thecoil spring 58 in the direction in which thedoor 50 blocks theopening 18. It will be noted that it is preferable to further projectingly dispose, on the rear side of the support table 60, a support table 66 that supports theshaft 52 when theopening 18 is open. - Further, a
tongue portion 56 for opening and closing thedoor 50 is disposed on the front end portion of thedoor 50 so as to project outward. Thetongue portion 56 is configured to engage with an opening/closing member (not shown) of thedrive device 70 in accompaniment with the loading of therecording tape cartridge 10 into thedrive device 70. Thus, thedoor 50 is opened counter to the biasing force of thecoil spring 58. - Next, an example of the
drive device 70 into which therecording tape cartridge 10 is loaded will be described. As shown inFIG. 5 toFIG. 7B , thedrive device 70 includes a take-up reel 80 that houses theleader block 85, which grips and pulls out theleader pin 30 from therecording tape cartridge 10, and around which take-up reel 80 is wound the recording tape T that has been pulled out via theleader pin 30. - Additionally, the take-
up reel 80 has substantially the same configuration as that of thereel 20. That is, the take-up reel 80 includes a bottomed circular cylinder-shapedreel hub 82 that configures an axial center portion (winding core portion) of the take-up reel 80, alower flange 86 that is integrally molded with the lower end portion of thereel hub 82, and anupper flange 84 that is screwed (fixedly attached) to and integrally configured with the upper end portion of thereel hub 82 via a pressing plate (not shown) made of metal. Ametal ring 82B that has a circular cylinder shape and is made of aluminium, for example, is integrally fixedly attached by insert molding to the inner peripheral surface side of aresin portion 82A that configures thereel hub 82. - Additionally, a flexural modulus E in the radial direction of the
reel hub 82 is equal to or greater than 16.0 GPa and preferably equal to or greater than 19.2 GPa. Further, thereel hub 82 is formed such that, when seen in a side sectional view, the radius of the outer peripheral surface of thereel hub 82 on theupper flange 84 side is larger than the radius of the outer peripheral surface of thereel hub 82 on thelower flange 86 side, and a difference ΔR between the radius of thereel hub 82 on theupper flange 84 side and the radius of thereel hub 82 on thelower flange 86 side is in the range of 5 μm to 60 μm (the ratio of the difference ΔR between the radius of thereel hub 82 on theupper flange 84 side and the radius of thereel hub 82 on thelower flange 86 side is in the range of 0.00039 to 0.00474 with respect to the width of the recording tape T). These are the same as thereel 20. - Further, because it suffices as long as the radii of the
reel hub 82 are different between theupper flange 84 side and thelower flange 86 side in the outer shape of thereel hub 82, the outer peripheral surface of thereel hub 82 does not have to have a tapered shape where its upper side and its lower side are interconnected by a straight line when seen in a side view. In other words, it is alright if there are fine concavo-convexities in the outer peripheral surface of thereel hub 82, and the outer peripheral surface of thereel hub 82 may have a shape where its upper side and its lower side are interconnected by a curved line when seen from the side. Moreover, the outer peripheral surface of thereel hub 82 may be curved when seen from the side, or part of the outer peripheral surface of thereel hub 82 may be parallel to the axial line of thereel hub 82. - Moreover, the mutually opposing surfaces of the
upper flange 84 and thelower flange 86 are formed as taperedsurfaces 84A and 86A (seeFIG. 6 ) where the distance between the flanges gradually increases toward the outer side (outer peripheral edge side), and the fluctuation width in the width direction of the recording tape T that has been wound around thereel hub 82 is controlled by theupper flange 84 and thelower flange 86. These are also the same as thereel 20. - Incidentally, as shown in
FIG. 7A andFIG. 7B , theleader block 85 that grips theleader pin 30 and has an arcuate shape when seen in plan view is disposed in thereel hub 82 of the take-up reel 80 such that theleader block 85 is capable of being attached to and detached from (capable of being housed in) thereel hub 82. Part of themetal ring 82B is exposed to aflat surface 83 of thereel hub 82 that is exposed in a state where theleader block 85 has been removed from thereel hub 82, and aslit portion 81 that allowsleader tape 87 that is attached to one end portion of theleader block 85 is formed in the height direction of themetal ring 82B (the axial direction of the reel hub 82). - Additionally, the
leader block 85 is attached to thereel hub 82 in a state where aflat surface 85B of theleader block 85 faces theflat surface 83 of thereel hub 82, and theleader block 85 configures part of the outer peripheral surface (take-up surface) of thereel hub 82 in this state. Here, it is necessary for a circular arc-shaped surface (take-up surface) 85C of theleader block 85 to be given the same shape as that of the outer peripheral surface of thereel hub 82. - That is, the
leader block 85 configures part of the take-up surface of thereel hub 82 in a state where theleader block 85 is attached to thereel hub 82, so when the recording tape T is wound around thereel hub 82 when there is a step between the circular arc-shapedsurface 85 of theleader block 85 and the outer peripheral surface of thereel hub 82, the potential for so-called “projection” to occur because of this step and for dropout to arise at that portion and lead to an error becomes greater. - For that reason, the circular arc-shaped
surface 85C of theleader block 85 is given the same shape as that of the outer peripheral surface of thereel hub 82, whereby it is ensured that the circular arc-shapedsurface 85C of theleader block 85 and the outer peripheral surface of thereel hub 82 become substantially even in a state where theleader block 85 is attached to thereel hub 82 and that a step does not arise across the entire outer peripheral surface of thereel hub 82. - Further, plural tape guides 72, 74, 76 and 78 are disposed in the drive device 70 (here, four tape guides are disposed). The tape guides 72, 74, 76 and 78 respectively include circular cylinder-shaped
hubs flanges hubs flanges hubs hubs recording tape cartridge 10 loaded inside thedrive device 70. Additionally, a recording andplayback head 88 is disposed between thetape guide 74 and thetape guide 76, and recording and playback of information with respect to the recording tape T is performed by the recording andplayback head 88. - Next, the action of the
recording tape cartridge 10 and thedrive device 70 of the above-described configurations will be described. In therecording tape cartridge 10 of the above-described configuration, when therecording tape cartridge 10 is not in use (during storage or during transport) when therecording tape cartridge 10 is not loaded in thedrive device 70, theopening 18 is blocked by thedoor 50. Then, when the recording tape T is to be used, therecording tape cartridge 10 is loadedfront wall 12A first inside thedrive device 70 along the direction of arrow A. - Then, the
recording tape cartridge 10 is inserted into an unillustrated bucket, and the opening/closing member disposed in the bucket (the drive device 70) engages with thetongue portion 56 of thedoor 50. Then, in this state, when therecording tape cartridge 10 moves further in the direction of arrow A, the opening/closing member causes thetongue portion 56 to move relatively rearward counter to the biasing force of thecoil spring 58. Then, thedoor 50 on which thetongue portion 56 is projectingly disposed slides rearward inside thegroove portions 64 along theright wall 12B to open theopening 18. - In this manner, when the
recording tape cartridge 10 is loaded a predetermined depth in the drive device 70 (the bucket) and theopening 18 is completely opened, the bucket housing therecording tape cartridge 10 is lowered a predetermined height, and a positioning member (not shown) of thedrive device 70 is relatively inserted into a positioning hole portion (not shown) formed in thelower case 16. Thus, therecording tape cartridge 10 is accurately positioned in a predetermined position inside thedrive device 70, and further sliding of the door 50 (movement rearward) is controlled. - Further, because of the downward movement of the recording tape cartridge 10 (the bucket), the drive gear relatively enters the
gear opening 40, engages with thereel gear 44, and causes thereel 20 to rise to a predetermined height (seeFIG. 6 ). Then, in a state where the drive gear and thereel gear 44 are completely meshed, thereel plate 46 is attracted to and held by the magnetic force of the annular magnet disposed inside the drive gear, whereby thereel 20 is placed in an unlocked state where it becomes relatively rotatable with respect to thecase 12 inside thecase 12 while the meshing of thereel gear 44 with respect to the drive gear is maintained. - Meanwhile, the leader block 85 (see
FIG. 7A ) disposed in thedrive device 70 enters thecase 12 through the openedopening 18 and grips and pulls out theleader pin 30 positioned and held in thepin holding portions 36. It will be noted that, at this time, thehooks 85A of theleader block 85 can be reliably caused to lock into theannular grooves 32 in theleader pin 30 because therecording tape cartridge 10 is accurately positioned inside thedrive device 70. Further, thereel 20 can rotate in accompaniment with the pulling-out of theleader pin 30 because thereel 20 has been released from its rotationally locked state. - In this manner, as shown in
FIG. 7B , the take-up reel 80 rotates, whereby theleader block 85 that holds theleader pin 30 that has been pulled out from theopening 18 is attached to (housed in) thereel hub 82 so as to configure part of thereel hub 82. Then, the take-up reel 80 and thereel 20 are driven to rotate synchronously, whereby the recording tape T is sequentially pulled out from thecase 12 while being taken up on the take-up reel 80. - Further, at this time, as shown in
FIG. 5 andFIG. 6 , the recording tape T that has been pulled out from the inside of thecase 12 slidingly contacts thetape guide 72 disposed most proximate to therecording tape cartridge 10. Thetape guide 72 is supported such that it may freely rotate and is attached such that its height position is, with respect to the width direction (height direction) of thereel hub 22, either in a central position or a position that is eccentrically located either higher or lower than the central position. Here, thetape guide 72 is attached such that its center position in its width direction (height direction) is eccentrically located in a lower position than the center position in the width direction (height direction) of thetape reel 22, for example. - Consequently, the recording tape T slidingly contacting the
tape guide 72 travels in a state where its upper edge is controlled by theupper flange 72A of thetape guide 72. Next, the recording tape T slidingly contacts thetape guide 74, which is supported such that it may freely rotate. Thetape guide 74 is attached such that its center position in its width direction (height direction) is eccentrically located in a higher position than the center position in the width direction (height direction) of thetape reel 22, and the lower edge of the recording tape T is controlled by thelower flange 74B of thetape guide 74. - Next, the recording tape T, whose position is controlled by the
tape guide 74, slidingly contacts thetape guide 76, which is supported such that it may freely rotate. It will be noted that the recording tape T slidingly contacts the recording andplayback head 88 before it slidingly contacts thetape guide 76. Conversely from thetape guide 74, that is, similar to thetape guide 72, thetape guide 76 is attached such that its center position in its width direction (height direction) is eccentrically located in a lower position than the center position in the width direction (height direction) of thereel hub 22, and the upper edge of the recording tape T is controlled by theupper flange 76A of thetape guide 76. - Finally, the recording tape T, whose position is controlled by the
tape guide 76, slidingly contacts thetape guide 78, which is supported such that it may freely rotate. Similar to thetape guide 74, thetape guide 78 is attached such that its center position in its width direction (height direction) is eccentrically located in a higher position than the center position in the width direction (height direction) of thereel hub 22, and the lower edge of the recording tape T is controlled by thelower flange 78B of thetape guide 78. - In this manner, when the height positions (positions in the width direction) of the tape guides 72, 74, 76 and 78 inside the
drive device 70 are mutually different along the tape path of the recording tape T, there is the advantage that control of the position in the width direction (vertical direction) of the recording tape T can be performed appropriately. It will be noted that, because each of the tape guides 72, 74, 76 and 78 is supported such that it may freely rotate, there are few instances where the edges of the recording tape T sustain damage due to the tape guides 72, 74, 76 and 78. - In this manner, when the
leader pin 30 becomes housed in thereel hub 82 of the take-up reel 80 while the position of the recording tape T in its width direction (vertical direction) is controlled by the tape guides 72, 74, 76 and 78, the take-up reel 80 and thereel 20 are synchronously driven to rotate, whereby the recording tape T is sequentially pulled out from thecase 12 while being taken up on the take-up reel 80, and recording and playback of information is performed by the recording andplayback head 88 disposed between the predetermined tape guides 74 and 76. - Here, the recording and
playback head 88 is supported such that it is movable in the vertical direction (height direction) by an unillustrated actuator, for example, follows servo signals S (seeFIG. 8 ) disposed on the recording tape T, and is configured to be movable in the width direction of the recording tape T (the axial direction of thereel hubs 22 and 82). - As shown in
FIG. 8 , for example, the servo signals S are configured in groups. Here, four (or five, etc.) servo signals S arranged parallel to each other form one pattern P, and two mutually adjacent patterns P form one group of servo signals S (refer to the circled portion inFIG. 8 ). Each of these groups of servo signals S has a substantial truncated V-shape. The groups of servo signals S formed in substantial truncated V-shapes are disposed in one row each in the vicinities of the upper edge and the lower edge of the recording tape T such that the wider sides of the inverted substantial truncated V-shapes face outward. - According to such servo signals S, when the detection time (distance) between two groups of the servo signals S (indicated by W in
FIG. 8 ) becomes long, it is understood that the position of the traveling recording tape T has shifted either up or down with respect to the recording andplayback head 88, whereby the position in the vertical direction (height direction) of the recording andplayback head 88 can be adjusted. - In the
reel 20 and the take-up reel 80 of the present embodiment, the elastic moduli E in the radial direction of thereel hubs reel hubs upper flanges reel hubs lower flanges reel hubs lower flanges reel hubs lower flanges 26 and 86 (small radius side) of thereel hubs - In other words, fluctuation in the position of the recording tape T in the vertical direction (the axial direction of the
reel 20 and the take-up reel 80) is appropriately controlled, and the traveling position of the recording tape T can be stabilized. Consequently, by using the edge of the recording tape T on the side of thelower flanges - In this manner, the recording tape T, with respect to which recording and playback of information has ended without error as a result of the recording tape T slidingly contacting the recording and
playback head 88 while the height position (position in the width direction) of the recording tape T is controlled by the tape guides 72, 74, 76 and 78, the shapes of thereel hubs reel 20 and the take-up reel 80 and the orientation of the curvature of the recording tape T, is rewound onto thereel 20 as a result of the drive gear and the take-up reel 80 reversely rotating. - When the recording tape T is completely rewound onto the
reel 20 and theleader pin 30 is held in thepin holding portions 36, the bucket housing therecording tape cartridge 10 rises a predetermined height, the positioning member is pulled out from the positioning hole portion, the drive gear is pulled out from thegear opening 40, and the drive gear disengages from thereel gear 44. Then, thereel 20 is lowered to its original height position inside therecording tape cartridge 10. - Thereafter, the
recording tape cartridge 10 is moved in the opposite direction of the direction of arrow A by an unillustrated ejecting mechanism, and in accompaniment with this movement, thedoor 50 is slid by the biasing force of thecoil spring 58 in the direction in which thedoor 50 blocks theopening 18 to completely block the opening 18 (thedoor 50 returns to its initial state). In this manner, therecording tape cartridge 10 whoseopening 18 has been blocked is completely ejected from the inside of the drive device 70 (the bucket). - Next, the action and effects of the above-described
reel 20 and take-up reel 80 will be described in greater detail. It will be noted that, because the action and effects of the take-up reel 80 are substantially the same as the action and effects of thereel 20, thereel 20 will be mainly described below and description of the take-up reel 80 will be appropriately omitted. - As shown in
FIG. 3 , thereel 20 pertaining to the present embodiment is configured as a result of thereel hub 22 and thelower flange 26 being integrally molded, theupper flange 24 being welded to and integrated with thereel hub 22, and themetal ring 22B made of aluminium or the like being integrally fixedly adhered by inserted molding to the inner peripheral surface side of theresin portion 22A of thereel hub 22. Additionally, the flexural modulus E in the radial direction of thereel hub 22 is equal to or greater than 16.0 GPa and preferably equal to or greater than 19.2 GPa. - Further, the radius of the outer peripheral surface of the reel hub 22 (the
resin portion 22A) on theupper flange 24 side is larger than the radius of the outer peripheral surface of the reel hub 22 (theresin portion 22A) on thelower flange 26 side, and the difference ΔR between the radius on theupper flange 24 side of thereel hub 22 and thelower flange 26 side of thereel hub 22 is in the range of 5 μm to 60 μm (the ratio of the difference ΔR between the radius on theupper flange 24 side of thereel hub 22 and the radius on thelower flange 26 side of thereel hub 22 with respect to the width of the recording tape T is 0.00039 to 0.00474). - Here, usually the recording tape T is wound around the reel hub such that the recording tape T moves toward the
upper flange 24 side or thelower flange side 26 because of differences in the polarity of the curvature of the recording tape T. InFIG. 16B andFIG. 16B , there are shown examples of winding form measurement charts where negative curvature recording tape T and positive curvature recording tape T are wound around a conventional reel hub (not shown) where the radius of the outer peripheral surface is substantially the same on theupper flange 24 side and thelower flange 26 side. It will be noted that fluctuation of the winding surface midway is omitted inFIG. 16 andFIG. 16B . - As shown in
FIG. 16A , when the polarity representing the orientation of the curvature of the recording tape T is in a negative direction (negative curvature), the recording tape T moves toward theupper flange 24 side along the axial direction of the reel hub as the recording tape T is wound around the reel hub. Additionally, as shown inFIG. 16B , when the polarity representing the orientation of the curvature of the recording tape T is in a positive direction (positive curvature), the recording tape T moves toward thelower flange 26 side along the axial direction of the reel hub as the recording tape T is wound around the reel hub. In this manner, the direction in which the recording tape T moves changes depending on differences in the polarity of the curvature of the recording tape T. - Consequently, as shown in
FIG. 9A andFIG. 9B , the polarity representing the orientation of the curvature of the tape edge of the recording tape T wound around thereel hub 22 of thereel 20 pertaining to the present embodiment is in a positive direction (positive curvature). In other words, the recording tape T is wound around thereel hub 22 such that the side where the radius of curvature of the curvature of the tape edge of the recording tape T is small becomes thelower flange 26 side. Thus, the recording tape T can be made to appropriately move toward thelower flange 26 side, the winding form (winding shape) of the recording tape T can be made excellent, and the traveling reference of the recording tape T can be made to be on thelower flange 26 side (small radius side) of thereel hub 22. - Here, as comparative examples compared with the
reel 20 pertaining to the present embodiment, areel 120 shown inFIG. 17 andFIG. 18 and areel 220 shown inFIG. 19 will be described. First, thereel 120 shown inFIG. 17 andFIG. 18 will be described, but in each of thereels reel 20, the radii of outer peripheral surfaces ofreel hubs upper flanges reel hubs lower flanges - That is, the difference ΔR between the radius on the
upper flanges reel hubs lower flanges reel hubs upper flanges reel hubs lower flanges reel hubs - The
reel 120 shown inFIG. 17 andFIG. 18 includes a circular cylinder-shapedreel hub 122 that configures an axial center portion (winding core portion) of thereel 120, an annularupper flange 124 that is disposed on the upper end portion of thereel hub 122, and a disc-shapedlower flange 126 that is disposed on the lower end portion of thereel hub 122. Thereel hub 122 and the upper andlower flanges - That is, a circular cylinder-shaped upper
circular cylinder portion 124A is disposed vertically on the inner edge portion and on a concentric circumference of theupper flange 124, and a circular cylinder-shaped lowercircular cylinder portion 126A that has substantially the same diameter as that of the uppercircular cylinder portion 124A is disposed upright on the upper surface of thelower flange 126. Additionally, thereel hub 122 has an inner diameter dimension that is larger than outer diameter dimensions of the lowercircular cylinder portion 126A and the uppercircular cylinder portion 124A, and thereel hub 122 is capable of being fitted over the lowercircular cylinder portion 126A and the uppercircular cylinder portion 124A in a state of non-contact (in a state where a predetermined clearance is formed between the outer peripheral surfaces of the lowercircular cylinder portion 126A and the uppercircular cylinder portion 124A and the inner peripheral surface of the reel hub 122). - Further, the length of the
reel hub 122 is substantially the same as the sum of the length of the lowercircular cylinder portion 126A and the length of the uppercircular cylinder portion 124A, and awelding rib 125 whose cross section is triangular is disposed on, so as to project from, the center portion of the upper end surface of the lowercircular cylinder portion 126A (or the center portion of the lower end surface of the uppercircular cylinder portion 124A) along the circumferential direction thereof. Moreover, ribs (engaging portions) 123 of a predetermined length (including width) and a predetermined height are disposed coaxially and continuously in at least three places in substantially equidistant intervals on, so as to project from, the outer side of the lowercircular cylinder portion 126A of thelower flange 126, and engagement grooves (engaged portions) 122A of a predetermined length (including width) and a predetermined depth into which theribs 123 are capable of being inserted in a state where there is virtually no clearance in the circumferential direction of thereel hub 122 but where there is a predetermined clearance in the radial direction of thereel hub 122 are formed in the center portion of the lower end surface of thereel hub 122 in at least three places continuously along in the circumferential direction of thereel hub 122 and in substantially the same intervals as those of the opposingribs 123. - Consequently, the
reel hub 122 is fitted over the lowercircular cylinder portion 126A of thelower flange 126, theengagement grooves 122A in thereel hub 122 are caused to engaged with theribs 123 of thelower flange 126, thereel hub 122 is positioned (centered) with respect to thelower flange 126, the uppercircular cylinder portion 124A of theupper flange 124 is inserted inside thereel hub 122, the lower end surface of the uppercircular cylinder portion 124A is brought into contact with the upper end surface of the lowercircular cylinder portion 126A, and an ultrasonic wave is oscillated to melt thewelding rib 125 in this state, whereby the uppercircular cylinder portion 124A is welded to the lowercircular cylinder portion 126A. - In other words, the
upper flange 124, thelower flange 126 and thereel hub 122 are thus assembled in a state where they are coaxially disposed (in a state where coaxiality is maintained), thereel hub 122 is held by the upper andlower flanges reel hub 122 is made incapable of relative rotation with respect to the upper andlower flanges 124 and 126 (made incapable of moving relatively in the circumferential direction). Additionally, a predetermined clearance is formed in the radial direction of thereel hub 122 between theengagement grooves 122A and theribs 123, and a predetermined clearance is formed between the outer peripheral surfaces of the lowercircular cylinder portion 126A and the uppercircular cylinder portion 124A and the inner peripheral surface of the reel hub 122 (such that they do not contact). - For that reason, the
reel hub 122 and the upper andlower flanges reel hub 122 and the upper andlower flanges reel hub 122 were to become deformed by the coiling force F of the recording tape T, for example, there is no danger that theupper flange 124 or thelower flange 126 will be affected by that deformation and become deformed. Consequently, in thereel 120 of this configuration, the recording tape T can be caused to move toward thelower flange 126 side that is the small radius side of thereel hub 122 and be wound around thereel hub 122 because of the following synergistic effects (1) and (2). - (1) When tension is applied in a direction substantially perpendicular with respect to the axial line of the
reel hub 122 and the recording tape T is wound around thereel hub 122, the recording tape T moves toward thelower flange 126 side that is the small radius side of thereel hub 122 because of the imbalance in the distribution of the surface pressure acting on the recording tape T, and the recording tape T is wound around thereel hub 122. - (2) When the recording tape T is wound around the
reel hub 122 such that the side where the radius of curvature of the curvature of the tape edge of the recording tape T is small becomes the small radius side of thereel hub 122, the direction in which the recording tape T moves becomes thelower flange 126 side that is the small radius side of thereel hub 122. - On the other hand, the
reel 220 shown inFIG. 19 substantially corresponds to an instance where themetal ring 22B is omitted from thereel 20. Thereel 220 is configured by a bottomed circular cylinder-shapedreel hub 222 that configures an axial center portion (winding core portion) of thereel 220, alower flange 226 that is integrally molded with the lower end portion of thereel hub 222, and anupper flange 224 that is ultrasonically welded to and integrated with the upper end portion of thereel hub 222. Consequently, when thereel hub 222 of thereel 220 becomes deformed by the coiling force F of the recording tape T that is wound around thereel hub 222, for example, theupper flange 224 and thelower flange 226 are affected by that deformation and become deformed such that the distance between theupper flange 224 and thelower flange 226 becomes narrower. - In other words, because the
reel hub 222 and the upper andlower flanges reel 220 are integrally configured, thereel 220 has a dependent structure where thereel hub 222 and the upper andlower flanges upper flange 224 and thelower flange 226 become deformed in accompaniment with deformation of thereel hub 222, or thereel hub 222 becomes deformed in accompaniment with deformation of theupper flange 224 and the lower flange 226). For that reason, in thereel 220 of this configuration, the recording tape T can be caused to move toward thelower flange 226 side that is the small radius side of thereel hub 222 and be wound around thereel hub 222 because of the following synergistic effects (1) to (3). - (1) When tension is applied in a direction substantially perpendicular with respect to the axial line of the
reel hub 222 and the recording tape T is wound around thereel hub 222, the surface pressure applied to thereel hub 222 becomes larger on theupper flange 224 side than on thelower flange 226 side of thereel hub 222. For that reason, the amount of deformation of the upper andlower flanges upper flange 224 side than on thelower flange 226 side. Thus, the recording tape T moves toward thelower flange 226 side that is the small radius side of thereel hub 222 and is wound around thereel hub 222. - (2) When tension is applied in a direction substantially perpendicular with respect to the axial line of the
reel hub 222 and the recording tape T is wound around thereel hub 222, the recording tape T moves toward thelower flange 226 side that is the small radius side of thereel hub 222 because of the imbalance in the distribution of the surface pressure acting on the recording tape T, and the recording tape T is wound around thereel hub 222. - (3) When the recording tape T is wound around the
reel hub 222 such that the side where the radius of curvature of the curvature of the tape edge of the recording tape T is small becomes the small radius side of thereel hub 222, the direction in which the recording tape T moves becomes thelower flange 226 side that is the small radius side of thereel hub 222. - It will be noted that, when the rigidity of the
reel hub 222 is improved, it becomes difficult for thereel hub 222 to become deformed by the coiling force F of the recording tape T, so the effect resulting from the distance between the upper andlower flanges reel 120, the recording tape T is caused to move toward thelower flange 226 side that is the small radius side of thereel hub 222 and is wound around thereel hub 222 by two synergistic effects—that is, the synergistic effects of (2) and (3). In other words, when the rigidity of thereel hub 222 is improved, structural differences virtually disappear between thereel 220 and thereel 120. - Further, when the recording tape T is wound around the
reel hub 22, the resistance acting on the recording tape T from thereel hub 22 becomes larger the higher the rigidity (flexural modulus E in the radial direction) of thereel hub 22 is. Additionally, in thereel hub 22 disposed with the difference ΔR between the radii on both end portions, the recording tape T is caused to move toward the small radius side of thereel hub 22 by the component force of that resistance. In other words, in thereel hub 22, it is easier for the recording tape T to be caused to move toward the small radius side of thereel hub 22 when the rigidity (flexural modulus E in the radial direction) is high and the difference ΔR between the radii is large. - In the
reel 20 pertaining to the present embodiment, the rigidity of thereel hub 22 is improved because themetal ring 22B is integrally disposed by insert molding (or by press-fitting or the like) in theresin portion 22A of thereel hub 22. Consequently, in thereel 20 pertaining to the present embodiment, substantially the same action and effects as those of thereel 120 are obtained. - Below, that the recording tape T moves toward the small radius side of the
reel hub 22 and is wound around thereel hub 22 when the recording tape T is wound around thereel 20 having this configuration—that is, that the traveling reference of the recording tape T is made to be on the small radius side of thereel hub 22—and that the winding form (winding shape) becomes excellent will be described on the basis of actual experimental data. It will be noted that, for the convenience of explanation, a positive value will represent the difference ΔR between the radii in an instance where the radius of the outer peripheral surface of thereel hub 22 on theupper flange 24 side is larger than the radius of the outer peripheral surface of thereel hub 22 on thelower flange 26 side, and a negative value will represent the difference ΔR between the radii in the opposite instance (when the radius of the outer peripheral surface of thereel hub 22 on thelower flange 26 side is larger than the radius of the outer peripheral surface of thereel hub 22 on theupper flange 24 side). - In
FIG. 20 toFIG. 23 , there are shown winding form measurement charts when negative curvature recording tape T and positive curvature recording tape T are wound around thereel 20 where the structures and materials of thereel hub 22 are different. That is,FIG. 20 is a winding form measurement chart when negative curvature recording tape T (amount of curvature ΔD=−0.18 mm) is wound around a reel (not shown) that has, similar to thereel 220, a dependent structure where deformation of thereel hub 22, theupper flange 24 and thelower flange 26 associatively acts on/affects each of them, thereel hub 22 is configured by just theresin portion 22A, the material thereof is polycarbonate (PC; elastic modulus is 3.6 GPa) to which 10% glass fiber (GF) has been added, and the difference ΔR between the radii of thereel hub 22 is ΔR=−0.003 mm (−3 μm) (the difference ΔR between the radii is close to ±0). - Additionally,
FIG. 21 is a winding form measurement chart when positive curvature recording tape T (amount of curvature ΔD=+0.90 mm) is wound around thereel 20 that has, similar to thereel 220, a dependent structure where deformation of thereel hub 22, theupper flange 24 and thelower flange 26 associatively acts on/affects each of them, thereel hub 22 is configured by just themetal ring 22B, the material thereof is aluminium (Al; elastic modulus is 70 GPa), and the difference ΔR between the radii of thereel hub 22 is ΔR=+0.040 mm (+40 μm). - It will be understood from
FIG. 20 andFIG. 21 that the winding measurement chart shown inFIG. 21 is extremely excellent. That is, when thereel 20 has a dependent structure where deformation of thereel hub 22, theupper flange 24 and thelower flange 26 associatively acts on/affects each of them, when the rigidity of thereel hub 22 is raised, the recording tape T can be caused to move toward the small radius side of thereel hub 22 and be wound around the reel hub 22 (the traveling reference of the recording tape T can be made to be on the small radius side of the reel hub 22), and the winding form (winding shape) of the recording tape T can be made excellent. It will be noted that, althoughFIG. 21 is a winding form measurement chart in an instance where thereel hub 22 is configured by just themetal ring 22B, the same is true even when thereel hub 22 is configured by theresin portion 22A and themetal ring 22B and the elastic modulus thereof is 70 GPa. - On the other hand,
FIG. 22 is a winding form measurement chart when negative curvature recording tape T (amount of curvature ΔD=−0.18 mm) is wound around a reel (not shown) that has, similar to thereel 120, an independent structure where deformation of thereel hub 22, theupper flange 24 and thelower flange 26 does not associatively act on/affect each of them, thereel hub 22 is configured by just theresin portion 22A, the material thereof is polycarbonate (PC; elastic modulus is 3.6 GPa) to which 10% glass fiber (GF) has been added, and the difference ΔR between the radii of thereel hub 22 is ΔR+0.002 mm (+2 μm) (the difference ΔR between the radii is close to ±0). - Additionally,
FIG. 23 is a winding form measurement chart when negative curvature recording tape T (amount of curvature ΔD=−0.18 mm) is wound around thereel 20 that has, similar to thereel 120, an independent structure where deformation of thereel hub 22, theupper flange 24 and thelower flange 26 does not associatively act on/affect each of them, thereel hub 22 is configured by just themetal ring 22B, the material thereof is aluminium (Al; elastic modulus is 70 GPa), and the difference ΔR between the radii of thereel hub 22 is ΔR=−0.043 mm (−43 μm). - It will be understood from
FIG. 22 andFIG. 23 that the winding measurement chart shown inFIG. 23 is extremely excellent. That is, even when the reel has an independent structure where deformation of thereel hub 22, theupper flange 24 and thelower flange 26 does not associatively act on/affect each of them, when the rigidity of thereel hub 22 is raised, the recording tape T can more effectively be caused to move toward the small radius side of thereel hub 22 and be wound around the reel hub 22 (the traveling reference of the recording tape T can be made to be on the small radius side of the reel hub 22), and the winding form (winding shape) of the recording tape T can be made excellent. - It will be noted that, although
FIG. 23 is a winding form measurement chart when thereel hub 22 is configured by just themetal ring 22B, the same is true even when thereel hub 22 is configured by theresin portion 22A and themetal ring 22B and the elastic modulus thereof is 70 GPa. Further, inFIG. 23 , negative curvature recording tape T is wound around thereel hub 22 and the recording tape T is caused to move toward theupper flange 24 side because the radius of the outer peripheral surface of thereel hub 22 on theupper flange 24 side is smaller than the radius of the outer peripheral surface of thereel hub 22 on thelower flange 26 side (because the radius on thelower flange 26 side is larger than the radius on theupper flange 24 side), but the action and effects thereof are the same as those that are shown inFIG. 21 . - Here, Table 2 shows evaluations in regard to the winding form of the recording tape T and the tape edge when the difference ΔR between the radius on the
upper flange 24 side of thereel hub 22 and the radius on thelower flange 26 side of thereel hub 22—that is, the ratio of the difference ΔR between the radius on theupper flange 24 side of thereel hub 22 and the radius on thelower flange 26 side of thereel hub 22 with respect to the width (½ inch width, substantially 12.65 mm) of the recording tape T—is changed. It will be noted that Table 2 shows evaluations in regard to thereel hub 22 where the radius of the outer peripheral surface on theupper flange 24 side is larger than the radius of the outer peripheral surface on thelower flange 26 side, and therefore the “+” sign is omitted. -
TABLE 2 Ratio of Difference between Radii on Difference (mm) Upper Flange Side between Radius on and Lower Flange Upper Flange Side Side of Reel Hub and Radius on with respect to Lower Flange Side Tape Width Winding Form State of Example of Reel Hub Dimension of Tape Tape Edge* 1 0.080 0.00632 ∘ x to 2 0.060 0.00474 ∘ □ 3 0.050 0.00400 ∘ ∘ 4 0.040 0.00316 ∘ ∘ 5 0.020 0.00158 □ ∘ 6 0.007 0.00055 □ ∘ 7 0.005 0.00039 □ ∘ 8 0.003 0.00237 ∘ 9 0.000 0.00000 x to ∘ *∘ = extremely good; □ = good; = somewhat bad; x = bad - As will be understood from Table 2, the winding form is not good when the difference ΔR between the radius on the
upper flange 24 side of thereel hub 22 and the radius on thelower flange 26 side of thereel hub 22 with respect to the width of the recording tape T is less than 0.005 mm (5 μm) (when the ratio of the difference ΔR between the radius on theupper flange 24 side of thereel hub 22 and the radius on thelower flange 26 side of thereel hub 22 with respect to the width of the recording tape T is less than 0.00039). In other words, either the effect of causing the recording tape T to be wound around thereel hub 22 to move toward the small radius side of thereel hub 22 is not obtained, or it is also conceivable that the shape of thereel hub 22 cannot be accurately grasped due to the precision of measurement. - Further, the winding form is good when the difference ΔR between the radius on the
upper flange 24 side of thereel hub 22 and the radius on thelower flange 26 side of thereel hub 22 with respect to the width of the recording tape T is greater than 0.060 mm (60 μm) (when the ratio of the difference ΔR between the radius on theupper flange 24 side of thereel hub 22 and the radius on thelower flange 26 side of thereel hub 22 with respect to the width of the recording tape T is greater than 0.00474), but radiation in the radial direction whose origin point is in the vicinity of thereel hub 22 and tape edge damage can be seen. - In other words, it will be understood that, when the difference ΔR between the radius on the
upper flange 24 side of thereel hub 22 and the radius on thelower flange 26 side of thereel hub 22 becomes larger, the component force of resistance acting on the recording tape T becomes larger when the recording tape T is wound around thereel hub 22, so it becomes easier for the recording tape T to move toward thelower flange 26 side that is the small radius side of thereel hub 22 and the winding form becomes good, but when the difference ΔR between the radii is too large, there is the danger for the recording tape T to be pushed excessively toward thelower flange 26 side and sustain tape edge damage such that so-called radiation occurs, for the recording tape T to interfere with thelower flange 26 during travel and further sustain tape edge damage, and in addition for phenomena that develop into defects such as cinching to occur. - For this reason, in the
reel 20, the difference ΔR between the radius on theupper flange 24 side of thereel hub 22 and the radius on thelower flange 26 side of thereel hub 22 is in the range of 5 μm to 60 μm with respect to the width of the recording tape T (½ inch width, substantially 12.65 mm). In other words, the ratio of the difference ΔR between the radius on theupper flange 24 side of thereel hub 22 and the radius on thelower flange 26 side of thereel hub 22 with respect to the width of the recording tape T is in the range of 0.00039 to 0.00474. - Further, when the amount of curvature ΔD of the recording tape T is too small (close to 0), the polarity of the recording tape T (the direction in which the recording tape T moves as it is wound around the reel hub) is undetermined, the position of the recording tape T fluctuates in the vertical direction, it becomes easier for disorderly winding to occur, and the winding surface becomes a so-called rough winding state. On the other hand, when the amount of curvature ΔD of the recording tape T is too large and the recording tape T has positive curvature, the recording tape T is pushed excessively toward the
lower flange 26 side and sustains tape edge damage such that so-called radiation occurs, the recording tape T interferes with thelower flange 26 during travel and further sustains tape edge damage, and in addition, phenomena that develop into defects such as cinching occur, and the tape traveling position moves excessively toward one side. For this reason, it is necessary to set the amount of curvature of the recording tape T to an appropriate amount of curvature ΔD. In Table 3, there are shown amounts of curvature ΔD of the recording tape T and states of the tape edge. -
TABLE 3 Amount of Curvature of State of Recording Tape (mm) Tape Edge* 1 0.10 2 0.15 □ 3 0.20 □ 4 0.50 ∘ 5 1.00 ∘ 6 1.50 ∘ 7 2.00 ∘ 8 2.50 □ 9 3.00 *∘ = extremely good; □ = good; = somewhat bad; x = bad - From the results of Table 3, it will be understood that problems do not arise in the tape edge when the amount of curvature ΔD of the recording tape T is in the range of 0.15 mm to 2.5 mm. For this reason, in the present embodiment, the absolute value of the amount of curvature ΔD of the recording tape T is set such that ΔD=0.15 mm to 2.5 mm. Thus, in the recording tape T, a tape traveling position that is appropriate and stable and a state where there is little disorderly winding can be achieved. In other words, disorderly winding is controlled, and the winding surface becomes closer to orderly winding.
- It will be will noted that it is more preferable for the absolute value of the amount of curvature ΔD to be in the range of ΔD=0.5 mm to 2.0 mm because the moving of the tape edge toward the
lower flange 26 side becomes appropriate when the recording tape T is wound around thereel hub 22. That is, there becomes less fluctuation in the position of the recording tape T in the axial direction of thereel hub 22 during travel, disorderly winding is controlled, and the recording tape T is orderly wound in a state along thelower flange 26 side, so tape edge damage is reduced in the recording tape T. - Consequently, when the amount of curvature ΔD of the recording tape T is small, such as 0.5 mm to 2.0 mm (when the radius of curvature of the curvature of the tape edge of the recording tape T is large), the recording tape T functions sufficiently even when the difference ΔR between the radius on the
upper flange 24 side of thereel hub 22 and the radius on thelower flange 26 side of thereel hub 22 is 5 μm to 60 μm with respect to the width of the recording tape T (the ratio of the difference ΔR between the radius on theupper flange 24 side of thereel hub 22 and the radius on thelower flange 26 side of thereel hub 22 with respect to the width of the recording tape T is 0.00039 to 0.00474). - However, there are also instances where, from the standpoints of the productivity of the
reel 20 and design freedom, the amount of curvature ΔD of the recording tape T is set large, such as 2.5 mm (there are also instances where the radius of curvature of the curvature of the tape edge of the recording tape T is set small). In these instances, it is preferable for the difference ΔR between the radius on theupper flange 24 side of thereel hub 22 and the radius on thelower flange 26 side of thereel hub 22 to be in the range of 7 μm to 50 μm with respect to the width of the recording tape T (for the ratio of the difference ΔR between the radius on theupper flange 24 side of thereel hub 22 and the radius on thelower flange 26 side of thereel hub 22 with respect to the width of the recording tape T to be 0.00055 to 0.00400). - When the difference ΔR between the radii is in this range, the recording tape T is not excessively pushed against the inner surface on the
lower flange 26 side of thereel hub 22 when the recording tape T is wound around thereel hub 22, the recording tape T does not interfere with thelower flange 26, and the moving of the tape edge of the recording tape T toward thelower flange 26 side becomes appropriate. In other words, even when the amount of curvature ΔD is 2.5 mm, bad traveling phenomena such as tape edge damage and abnormal sounds can be controlled, and an excellent winding form is obtained. - It will be noted that the necessary minimum rigidity of the reel hub 22 (the flexural modulus E in the radial direction of the reel hub 22) is determined from the experimental results in Table 1. That is, as will be understood from Table 1 and also from
FIG. 20 andFIG. 22 , the winding form is not good when the flexural modulus E in the radial direction of thereel hub 22 is 3.6 GPa. However, it will be understood that there are no problems as long as the flexural modulus E in the radial direction of thereel hub 22 is equal to or greater than 16.9 GPa. - Here, the numerical value 16.9 GPa is a value when it is assumed that 5% error is included in the elastic modulus Ea of the
resin portion 22A when its thickness is a and in the elastic modulus Eb of themetal ring 22B when its thickness is b, and when this error is removed, the flexural modulus E becomes 16.0 GPa. Thus, in the present embodiment, the flexural modulus E in the radial direction of thereel hub 22 is made equal to or greater than 16.0 GPa. Additionally, the flexural modulus E is more preferably equal to or greater than 19.2 GPa (a numerical value where 5% error is removed from 20.2 GPa). - In this manner, by making the flexural modulus E in the radial direction of the
reel hub 22 equal to or greater than 16.0 GPa and preferably equal to or greater than 19.2 GPa, the recording tape T that is wound around thereel hub 22 can be appropriately caused to move toward the small radius side (thelower flange 26 side) of thereel hub 22, and the winding form (winding shape) of the recording tape T can be made excellent. - As described above, in the
reel 20 pertaining to the present embodiment, the flexural modulus E in the radial direction of thereel hub 22 is made equal to or greater than 16.0 GPa, and the radius on theupper flange 24 side of thereel hub 22 is made larger than the radius on thelower flange 26 side of thereel hub 22, so the following actions (1) and (2) are provided. - (1) When tension is applied in a direction substantially perpendicular with respect to the axial line of the
reel hub 22 and the recording tape T is wound around thereel hub 22, the recording tape T moves toward thelower flange 26 side that is the small radius side of thereel hub 22 because of the imbalance in the distribution of the surface pressure acting on the recording tape T, and the recording tape T is wound around thereel hub 22. - (2) When the recording tape T is wound around the
reel hub 22 such that the side where the radius of curvature of the curvature of the tape edge of the recording tape T becomes the small radius side of thereel hub 22, the direction in which the recording tape T moves becomes thelower flange 26 side that is the small radius side of thereel hub 22. - In other words, according to the present embodiment, because of the synergistic effects of (1) and (2), the recording tape T can be appropriately caused to move toward the
lower flange 26 side that is the small radius side of thereel hub 22 and be wound around thereel hub 22. Consequently, fluctuation of the recording tape T in the axial direction of thereel hub 22 can be controlled, disorderly winding of the recording tape T can be controlled, and orderly windability can be improved (the winding form can be made excellent). - Thus, the occurrence of a step or one-layer protrusion or plural-layer protrusion from the winding surface of the recording tape T that has been wound around the
reel hub 22 can be controlled, and problems that occur as a result of the one-layer protruding recording tape T striking theupper flange 24 or thelower flange 26, bending and sustaining tape edge damage when the recording tape T receives a shock such as during transport, or when the recording tape cartridge is dropped, or during handling can be reduced. - Additionally, the tape traveling position can be stabilized because the position of the recording tape T can be controlled from fluctuating in the axial direction of the
reel hub 82 even during travel of the recording tape T inside thedrive device 70. In particular, fluctuation of the recording tape T in the axial direction of thereel hub 82 of the take-up reel 80, whose shape becomes complex and which is difficult to make highly precise because it is disposed with the function of housing theleader block 85, can be controlled even by thereel 20. For this reason, servo signal S reading errors (servo tracking errors) and data signal recording and playback errors that occur during travel can be reduced even in high density recording, and a reduction of so-called position error signals and off-track can be expected. - Further, when the thickness of the recording tape T is thick, the rigidity of the recording tape T also increases, so the strength of the tape edge increases, and it becomes difficult for problems such as tape edge damage to occur with respect also to pushing against the upper and
lower flanges - In other words, the rigidity of the recording tape T that is wound around the reel hub drops, the strength of the tape edges drops, and kinks resulting from one-layer protrusion and tape edge damage during travel become an even greater problem than has been the case up to now. In contrast, the
reel 20 of the present embodiment can control fluctuation in the position of the recording tape T, so thereel 20 can control the amount of protrusion of the one-layer protrusion phenomenon and the rate of occurrence itself. Thus, this becomes effective with respect to recording tape T whose thickness has been made thin (e.g., 6.9 μm or less). - Further, the orientation of the curvature of the recording tape T can also be changed by a heat treatment. That is, by performing an appropriate heat treatment in a state where the recording tape T has been taken up on a reel (not shown) where the outer peripheral surface of the
reel hub 22 is formed in a tapered shape, uniform curvature can be imparted by the shape fixing effect resulting from the creep phenomenon, and an excellent winding habit can be imparted to the recording tape. In the present embodiment, positive curvature recording tape T is used, but negative curvature recording tape T may also be used by making the radius of the outer peripheral surface of thereel hub 22 on theupper flange 24 side smaller than the radius of the outer peripheral surface of thereel hub 22 on thelower flange 26 side. The traveling reference in this instance becomes theupper flange 24 side (seeFIG. 23 ). - Further, in the present embodiment, the
metal ring 22B is integrated with theresin portion 22A by insert molding to form thereel hub 22, but themetal ring 22B may also be integrated with theresin portion 22B by press-fitting themetal ring 22B into the inside of theresin portion 22A. Moreover, the material of themetal ring 22B is not limited to aluminium and may also be stainless steel whose flexural modulus E is 190 GPa or greater, for example. Further, when thereel hub 22 is given a configuration disposed with themetal ring 22B (also includes instances where thereel hub 22 is configured by just themetal ring 22B), the rigidity of thereel hub 22 can be easily raised, but this does not mean that themetal ring 22B is invariably necessary. Thereel hub 22 may also be configured by just theresin portion 22A by adding a strengthening agent such as glass fiber during molding of thereel hub 22 so that the desired rigidity (a flexural modulus E equal to or greater than 16.0 GPa) can be ensured. - Further, in the
reel 20 pertaining to the present embodiment, thereel hub 22 and thelower flange 26 are integrally molded and theupper flange 24 is welded to thereel hub 22, but thereel hub 22 and theupper flange 24 may be integrally molded and thelower flange 26 may be welded to thereel hub 22, or theupper flange 24 and thelower flange 26 may be welded to both end portions of thereel hub 22, or thereel hub 22, theupper flange 24 and thelower flange 26 may be integrally molded. In other words, “integrally” mentioned in the present embodiment refers to a configuration where deformation of thereel hub 22, theupper flange 24 and thelower flange 26 associatively acts on/affects each of them and is a configuration where theupper flange 24 and/or thelower flange 26 becomes deformed in accompaniment with deformation of thereel hub 22 or where thereel hub 22 becomes deformed in accompaniment with deformation of theupper flange 24 and/or thelower flange 26. - Similarly, a configuration where the
reel hub 22, theupper flange 24 and thelower flange 26 are separately molded is also included in thereel 20 pertaining to the present embodiment. That is, “separately” mentioned in the present embodiment refers to a configuration where deformation of thereel hub 22, theupper flange 24 and thelower flange 26 does not associatively act on/affect each of them (they are mutually independent). It will be noted that the same is true also in regard to the take-up reel 80 as it is for thereel 20. Further, in the present embodiment, an example has been described where the invention is applied to therecording tape cartridge 10 that is configured by housing thereel 20 singly inside thecase 12, but the present invention is not limited to this. For example, the present invention may of course also be applied to a two-reel type recording tape cassette where two reels are housed inside a case.
Claims (19)
1. A tape reel comprising:
a hub around which recording tape is wound; and
flanges disposed on both end portions of the hub,
wherein the elastic modulus in a radial direction of the hub is equal to or greater than 16.0 GPa, the hub includes different radii on one end side thereof and another end side thereof, and the recording tape is wound around the hub such that the side where the radius of curvature of the curvature of the tape edge of the recording tape is small corresponds to the small radius side of the hub.
2. The tape reel of claim 1 , wherein the ratio of the difference between the radius on the one end side of the hub and the radius on the other end side of the hub with respect to the width of the recording tape is equal to or greater than 0.00039 and equal to or less than 0.00474.
3. The tape reel of claim 1 , wherein the width of the recording tape is substantially 12.65 mm, and the difference between the radius on the one end side of the hub and the radius on the other end side of the hub is equal to or greater than 5 μm and equal to or less than 60 μm.
4. The tape reel of claim 1 , wherein the absolute value of the amount of curvature of the recording tape is equal to or greater than 0.15 mm and equal to or less than 2.5 mm.
5. The tape reel of claim 1 , wherein the hub is configured to include a metal that is disposed integrally with a resin by insert molding or press-fitting.
6. The tape reel of claim 1 , wherein the thickness of the recording tape is equal to or less than 7.5 μm.
7. The tape reel of claim 1 , wherein the recording tape includes servo signals that serve as a positioning reference of a recording and playback head of a drive device, and the tape edge of the recording tape that has been wound around the hub that is on the small radius side of an outer peripheral surface of the hub serves as a servo tracking control reference during travel of the recording tape.
8. A recording tape cartridge comprising the tape reel of claim 1 and a case that rotatably houses the tape reel.
9. The recording tape cartridge of claim 8 , wherein the tape cartridge has a single tape reel configuration.
10. A take-up reel that is disposed inside a drive device and around which is wound recording tape that has been pulled out from a recording tape cartridge, the take-up reel comprising:
a hub around which the recording tape is wound; and
flanges disposed on both end portions of the hub,
wherein the elastic modulus in a radial direction of the hub is equal to or greater than 16.0 GPa, the hub includes different radii on one end side thereof and another end side thereof, and the side where the radius of curvature of the curvature of a tape edge of the recording tape is small is wound around the small radius side of the hub.
11. The take-up reel of claim 10 , wherein the ratio of the difference between the radius on the one end side of the hub and the radius on the other end side of the hub with respect to the width of the recording tape that is wound around the hub is equal to or greater than 0.00039 and equal to or less than 0.00474.
12. The take-up reel of claim 10 , wherein the width of the recording tape that is wound around the hub is substantially 12.65 mm, and the difference between the radius on the one end side of the hub and the radius on the other end side of the hub is equal to or greater than 5 μm and equal to or less than 60 μm.
13. The take-up reel of claim 10 , wherein the absolute value of the amount of curvature of the recording tape that is wound around the hub is equal to or greater than 0.15 mm and equal to or less than 2.5 mm.
14. The take-up reel of claim 10 , wherein the hub is configured to include a metal that is disposed integrally with a resin by insert molding or press-fitting.
15. The take-up reel of claim 10 , wherein the thickness of the recording tape that is wound around the hub is equal to or less than 7.5 μm.
16. The take-up reel of claim 10 , wherein the recording tape that is wound around the hub includes servo signals that serve as a positioning reference of a recording and playback head disposed in the drive device, and the tape edge of the recording tape that has been wound around the hub that is positioned on the small radius side of an outer peripheral surface of the hub serves as a servo tracking control reference during travel of the recording tape.
17. A pullout member that pulls out recording tape from a recording tape cartridge, is housed in the hub of the take-up reel of claim 10 , and is disposed with a take-up surface that configures part of an outer peripheral surface of the hub, wherein the elastic modulus of the take-up surface is equal to or greater than 16.0 GPa, the take-up surface includes different radii on one end side thereof and another end side thereof, and the take-up surface and the outer peripheral surface of the hub become substantially even in a state where the pullout member is housed in the hub.
18. A drive device including the take-up reel of claim 10 around which is wound recording tape that has been pulled out from a recording tape cartridge that has been loaded into the drive device.
19. A drive device of a recording tape cartridge, the drive device comprising:
a take-up reel that includes a hub around which recording tape is wound and flanges disposed on both end portions of the hub, with the recording tape that has been pulled out from the recording tape cartridge being wound around the take-up reel; and
a pullout member that pulls out the recording tape from the recording tape cartridge and includes a take-up surface that configures part of an outer peripheral surface of the hub when the pullout member is housed in the hub of the take-up reel,
wherein the elastic modulus in a radial direction of the hub and the elastic modulus of the take-up surface are equal to or greater than 16.0 GPa, the hub and the take-up surface each include different radii on one end side thereof and another end side thereof, the take-up surface of the pullout member becomes substantially even with an outer peripheral surface of the hub in a state where the pullout member is housed in the hub, and the side where the radius of curvature of the curvature of a tape edge of the recording tape is small is wound around the small radius side of the hub.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2007119574A JP2008276868A (en) | 2007-04-27 | 2007-04-27 | Tape reel, recording tape cartridge, machine reel, lead member, and drive apparatus |
JP2007-119574 | 2007-04-27 |
Publications (1)
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US20080265078A1 true US20080265078A1 (en) | 2008-10-30 |
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US12/109,891 Abandoned US20080265078A1 (en) | 2007-04-27 | 2008-04-25 | Tape reel, recording tape cartridge, take-up reel, pullout member, and drive device |
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US (1) | US20080265078A1 (en) |
JP (1) | JP2008276868A (en) |
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US20220358958A1 (en) * | 2021-04-28 | 2022-11-10 | Fujifilm Corporation | Magnetic tape cartridge and magnetic recording and reproducing device |
US11508410B2 (en) * | 2019-05-06 | 2022-11-22 | Quantum Corporation | Magnetic tape cartridge with increased data storage capacity |
US11972784B2 (en) | 2021-06-24 | 2024-04-30 | Fujifilm Corporation | Magnetic tape cartridge group and magnetic recording and reproducing device |
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JP2022143432A (en) * | 2021-03-17 | 2022-10-03 | ソニーグループ株式会社 | Tape reel, tape cartridge, and manufacturing device for tape reel |
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USD737347S1 (en) * | 2014-01-05 | 2015-08-25 | Makerbot Industries, Llc | Filament spool holder for three-dimensional printer |
KR102603943B1 (en) | 2015-06-11 | 2023-11-20 | 스미또모 가가꾸 가부시키가이샤 | Film roll, method of producing the same, and method of testing the same |
US20160362269A1 (en) * | 2015-06-11 | 2016-12-15 | Sumitomo Chemical Company, Limited | Film roll, method of producing the same, and method of testing the same |
KR20160146546A (en) * | 2015-06-11 | 2016-12-21 | 스미또모 가가꾸 가부시키가이샤 | Film roll, method of producing the same, and method of testing the same |
CN110994040A (en) * | 2015-06-11 | 2020-04-10 | 住友化学株式会社 | Film roll, method for producing same, and film |
US10689217B2 (en) * | 2015-06-11 | 2020-06-23 | Sumitomo Chemical Company, Limited | Film roll, method of producing the same, and method of testing the same |
USD900177S1 (en) | 2019-03-19 | 2020-10-27 | Makerbot Industries, Llc | Drawer for a three-dimensional printer |
US20220172743A1 (en) * | 2019-03-29 | 2022-06-02 | Sony Group Corporation | Tape reel and tape cartridge |
US11508410B2 (en) * | 2019-05-06 | 2022-11-22 | Quantum Corporation | Magnetic tape cartridge with increased data storage capacity |
US11495246B2 (en) * | 2020-01-31 | 2022-11-08 | Fujifilm Corporation | Magnetic tape cartridge and magnetic tape apparatus |
US20220277770A1 (en) * | 2021-02-26 | 2022-09-01 | Fujifilm Corporation | Magnetic tape container |
US11842752B2 (en) * | 2021-02-26 | 2023-12-12 | Fujifilm Corporation | Magnetic tape container |
US20220358958A1 (en) * | 2021-04-28 | 2022-11-10 | Fujifilm Corporation | Magnetic tape cartridge and magnetic recording and reproducing device |
US11972784B2 (en) | 2021-06-24 | 2024-04-30 | Fujifilm Corporation | Magnetic tape cartridge group and magnetic recording and reproducing device |
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Legal Events
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AS | Assignment |
Owner name: FUJIFILM CORPORATION, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SHIGA, HIDEAKI;REEL/FRAME:021227/0039 Effective date: 20080520 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |