JP2011187091A - Device and method for driving of magnetic tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic tape driving device capable of reducing mutual sticking of a magnetic tape and a magnetic head. <P>SOLUTION: When a transfer speed V of a magnetic tape 6 drops to a reference speed when stopping the magnetic tape 6 from its traveling state, a spacing between a magnetic head 1 and the magnetic tape 6 is enlarged by reducing tension of the magnetic tape 6 from a normal value to a predetermined value. The enlarged spacing enables reduction of a meniscus part generated between the magnetic head 1 and the magnetic tape 6 in the stopped state of the magnetic tape 6. By reducing the meniscus part, friction between the magnetic head 1 and the magnetic tape 6 is reduced, and sticking upon restarting transfer is reduced. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a magnetic tape driving device and a magnetic tape driving method.

  Magnetic tape, which is a kind of magnetic recording medium, has various uses such as audio tape, video tape, and computer tape. In particular, in the field of data backup tapes for computers, with a capacity of a hard disk to be backed up, a storage capacity of several hundred GB per volume is commercialized. In the future, it will be essential to increase the capacity of backup tapes in order to cope with further increases in the capacity of hard disks.

  A magnetic tape used as a backup tape has a shorter recording wavelength as the recording capacity further increases, and the surface is being smoothed in order to suppress deterioration in recording and reproducing characteristics due to spacing. By smoothing the surface of the magnetic tape, the contact area between the magnetic head and the magnetic tape increases, and friction at the interface between the two increases. In addition, in the case of magnetic tape to which a lubricant is added to improve durability, if the spacing between the magnetic head and the magnetic tape is reduced, the magnetic tape that is oozed out on the surface of the magnetic tape when the magnetic tape is stopped Adhesive force acts between the magnetic head and the magnetic head, and friction at the interface with the magnetic head may increase.

  In particular, when starting to transfer the magnetic tape from a state where the magnetic tape is in contact with the magnetic head and stopped, if the friction at the interface between the magnetic tape and the magnetic head increases, the magnetic tape or the magnetic head is damaged. May occur. As a countermeasure against friction between the magnetic head and the magnetic tape, for example, there is a technique disclosed in Patent Document 1.

  In Patent Document 1, in order to reduce the static friction between the magnetic tape and the magnetic head during magnetic recording / reproduction, the BOT part (BOT: Beginning of tape) and the EOT part (EOT: End of tape) of the magnetic tape are very small. A concave portion is formed. As a result, even when the magnetic head is located at the start or end of the magnetic tape 6, even if the transfer of the magnetic tape is started, the static friction is low, so that tape damage or the like can be suppressed.

JP 2006-127666 A

  When a coated magnetic tape to which lubricant is added is transported by a magnetic tape drive, the surface of the magnetic tape is soaked by the contact pressure applied to the magnetic tape at the sliding contact portion between the magnetic head and the magnetic tape. Get out. At this time, if the spacing between the magnetic head and the magnetic tape is small, the sticking force at the interface between the magnetic head and the magnetic tape is increased by the lubricant that has oozed out on the surface of the magnetic tape. It may stick to the magnetic head. In the configuration disclosed in Patent Document 1, even if the magnetic head and the magnetic tape are stuck when the transfer of the magnetic tape is stopped, the transfer of the magnetic tape is started as it is, so that the tape is damaged. There is a problem.

  An object of the present invention is to provide a magnetic tape driving device capable of reducing the sticking of a magnetic tape to a magnetic head in a state where the magnetic tape is stopped.

  The magnetic tape drive of the present application is a magnetic tape drive comprising a magnetic head unit having a magnetic head capable of recording or reproducing information by sliding on the magnetic tape, and a tape transfer means for transferring the magnetic tape. When the magnetic tape is moved from the transfer state to the stop state, the tape transfer is performed so that the tension of the magnetic tape is reduced to a predetermined value when it is detected that the transfer speed of the magnetic tape is lower than a reference speed. A control unit for controlling the means is provided.

  The magnetic tape drive of the present application is a magnetic tape drive comprising a magnetic head unit having a magnetic head capable of recording or reproducing information by sliding on the magnetic tape, and a tape transfer means for transferring the magnetic tape. When the magnetic tape is shifted from the stop state to the transfer state, the tape transfer means is configured to reduce the tension of the magnetic tape to a predetermined value while the transfer speed of the magnetic tape is lower than a reference speed. Is provided with a control unit for controlling the.

  The magnetic tape driving method of the present application is a magnetic tape driving device including a magnetic head unit including a magnetic head capable of recording or reproducing information by sliding contact with the magnetic tape, and a tape transfer unit that transfers the magnetic tape. A magnetic tape driving method for transferring the magnetic tape, wherein when the magnetic tape is moved from a transfer state to a stop state, it is detected that the transfer speed of the magnetic tape is lower than a reference speed. It reduces the tension.

  The magnetic tape driving method of the present application is a magnetic tape driving device including a magnetic head unit including a magnetic head capable of recording or reproducing information by sliding contact with the magnetic tape, and a tape transfer unit that transfers the magnetic tape. A magnetic tape driving method for transferring the magnetic tape, wherein when the magnetic tape is shifted from a stopped state to a running state, the tension of the magnetic tape is reduced while the transfer speed of the magnetic tape is lower than a reference speed. Is to lower.

  ADVANTAGE OF THE INVENTION According to this invention, it can reduce that a magnetic tape sticks to a magnetic head in the state which has stopped the magnetic tape.

Cross section of magnetic tape and magnetic head Cross section of magnetic layer and magnetic head Cross section of magnetic layer and magnetic head Graph showing the relationship between magnetic tape transfer speed and spacing Graph showing short durability stiction error map Block diagram of a magnetic tape drive device according to an embodiment Schematic diagram showing the configuration of magnetic tape Flowchart showing the flow of stop operation in the magnetic tape drive Flow chart showing flow of transfer start operation in magnetic tape drive Timing chart of stop operation and transfer start operation in magnetic tape drive

(Embodiment)
[1. Configuration of magnetic tape
FIG. 1 is a cross-sectional view of the magnetic tape 100 and the magnetic head 1. The magnetic tape 100 is a coating type multilayer magnetic tape having a magnetic layer 102 on a lower layer 101. In a coating type multi-layer magnetic tape, a lubricant is often added to the lower layer 101. The lower layer 101 has a large number of holes. In addition, a filler 103 made of alumina or the like is added to the magnetic layer 102. When the magnetic tape 100 shown in FIG. 1 is moved, for example, in the direction indicated by the arrow A and is brought into sliding contact with the magnetic head 1, a load is applied to the magnetic tape 100 at the sliding contact portion with the magnetic head 1. Here, when the filler 103 is present at the sliding contact portion of the magnetic tape 100 with the magnetic head 1, the filler 103 is pressed toward the lower layer 101, and the filler 103 crushes the holes in the lower layer 101. As a result, the lubricant added to the lower layer 101 passes through the pores of the magnetic layer 102 and oozes out to the surface of the magnetic layer 102. The lubricant 104 shown in FIG. 1 is a lubricant that has oozed out on the surface of the magnetic layer 102. The lubricant 104 that has oozed out on the surface of the magnetic layer 102 is transferred to the surface of the magnetic head 1. The lubricant 104 is effective to smoothly bring the magnetic tape 100 into sliding contact with the magnetic head 1. However, when the lubricant 104 exudes excessively, the magnetic tape 100 may stick to the magnetic head 1. Further, when the distance (spacing) between the magnetic head 1 and the magnetic tape 100 is reduced, the magnetic tape 100 adheres to the magnetic head 1 even if the amount of the lubricant 104 that exudes from the magnetic tape 100 is a normal amount. A phenomenon may occur.

  In addition to the case where the lubricant is added to the lower layer, the case where the lubricant is added to the magnetic layer, the case where the lubricant is top-coated on the magnetic layer, or a combination thereof, is similarly applied. If the surface of the magnetic tape 100 oozes out excessively, the magnetic tape 100 may stick to the magnetic head 1 in some cases.

  2A and 2B are views for explaining the mechanism by which the magnetic tape 100 adheres to the magnetic head 1, and are sectional views of the magnetic layer 102 and the magnetic head 1. FIG. 2A shows a case where the amount of the lubricant 104 that oozes out on the surface of the magnetic layer 102 is small, or a case where the spacing SP1 between the magnetic tape 100 and the magnetic head 1 is large. In the state shown in FIG. 2A, a drag in the directions indicated by arrows B1 and B2 acts on the contact portion P between the magnetic layer 102 and the magnetic head 1. On the other hand, in the portion Q1 where the magnetic layer 102 and the magnetic head 1 are separated and the lubricant 104 is located in the gap between the magnetic layer 102 and the magnetic head 1 (hereinafter referred to as a meniscus portion) Q1, the negative pressure of the lubricant 104b The adhesion force in the direction shown by arrows C1 and C2 due to the above acts. The meniscus portion Q2 also has an adhesion force in the same direction as indicated by arrows C1 and C2 by the same principle.

  FIG. 2B shows a case where the amount of the lubricant 104 that oozes out on the surface of the magnetic layer 102 is large, or a case where the spacing SP2 between the magnetic tape 100 and the magnetic head 1 is small. In the state shown in FIG. 2B, the meniscus portions Q11 to Q15 are increased as compared with the state shown in FIG. 2A, and the adhesion force in the direction indicated by the arrow acts on each meniscus portion. Therefore, the sum of the adhesion forces of all meniscus portions is larger in the state shown in FIG. 2B than in the state shown in FIG. 2A.

The frictional force F at the interface between the magnetic tape 100 and the magnetic head 1 is a friction coefficient K at a contact portion (for example, a portion indicated by reference numeral P in FIG. 2A) between the magnetic tape 100 and the magnetic head 1 and the cohesion of all meniscus portions. When the sum of the applied force is M and the contact pressure on the magnetic tape 100 is R,
F = K × (R + M)
It can ask for. That is, when the spacing between the magnetic head 1 and the magnetic tape 100 is reduced or the amount of the lubricant 104 at the interface between the magnetic head 1 and the magnetic tape 100 is increased, the meniscus portion is increased as shown in FIG. 2B. As a result, the adhesion force M increases. When the adhesion force M increases, the frictional force F increases as shown in the above formula.

  FIG. 3 is a graph showing the relationship between the spacing between the magnetic head 1 and the magnetic tape 100 and the transfer speed of the magnetic tape 100. FIG. 3 shows a result of measuring a spacing with respect to a transfer speed by performing a transfer test using any two types of magnetic tapes. Moreover, about one magnetic tape of two types of magnetic tapes, it measured with the magnetic tape after transferring 1000 passes. The tension of the magnetic tape during the test was 0.7 N, and the contact pressure at the sliding portion with respect to the magnetic head was 0.5 atm (14 g). As shown in FIG. 3, it can be seen that the spacing decreases as the transfer speed of the magnetic tape 100 decreases. In particular, it can be seen that the spacing at a transfer speed lower than 1 m / sec is significantly lower than the spacing at a transfer speed of 1 m / sec or higher. The reason why the spacing increases when the transfer speed of the magnetic tape 100 is 1 m / second or more is that an air layer (air gap) is easily generated between the magnetic tape 100 and the magnetic head 1, and the magnetic tape 100 is magnetic. This is because it floats slightly with respect to the head 1. On the other hand, when the transfer speed of the magnetic tape 100 is lower than 1 m / sec, an air layer is unlikely to be generated between the magnetic tape 100 and the magnetic head 1, and the magnetic tape 100 is in direct contact with the magnetic head 1. Spacing is reduced.

  Therefore, based on the principle described with reference to FIGS. 2A and 2B and the measurement result shown in FIG. 3, when the transfer speed of the magnetic tape 100 is lower than 1 m / second, the magnetic head 1 and the magnetic tape 100 Thus, it can be said that the magnetic tape 100 is likely to stick to the magnetic head 1 because the meniscus portion due to the lubricant is easily generated.

  In order to clarify the relationship between the transfer speed of the magnetic tape and the sticking of the magnetic tape to the magnetic head, the inventors conducted a durability test of the magnetic tape. The magnetic tape used for the test is a coating type magnetic tape compliant with the Hitachi Maxell LTO (Linear Tape Open) standard. The magnetic tape was loaded into a predetermined test apparatus, repeatedly transferred in a short length in a high-temperature and high-humidity atmosphere, and the number of stiction (sticking) errors at the longitudinal position of the predetermined magnetic tape was counted. FIG. 4 shows the test results. As shown in FIG. 4, the magnetic tape was repeatedly transported in a short length between the 200 m position and the 250 m position from the starting end. Specifically, the magnetic tape starts to be transferred from the 200 m position in the forward direction, is temporarily stopped at the 239 m position, is started again in the forward direction, and is stopped at the 250 m position. Next, the transfer is started in the reverse direction from the 250 m position, temporarily stopped at the 212 m position, is started again in the reverse direction, and is stopped at the 200 m position. This series of short length transfer was carried out a predetermined number of times. As a result, as shown in FIG. 4, it can be seen that a stiction error has occurred at the magnetic tape stop position (200 m position, 212 position, 239 m position, 250 m position).

  In this embodiment, in order to reduce the sticking of the magnetic tape to the magnetic head as described above, when the magnetic tape is transferred from the transfer state to the stop state, the transfer speed of the magnetic tape is lower than a predetermined speed. The main structural feature is to reduce the tension of the magnetic tape to a predetermined value. Hereinafter, a specific configuration of the magnetic tape driving device according to the present embodiment will be described.

[2. Configuration of magnetic tape drive unit]
FIG. 5 is a block diagram of the magnetic tape drive apparatus according to this embodiment. Note that the magnetic tape drive according to this embodiment is a device capable of linear recording of data on a computer tape.

  As shown in FIG. 5, the magnetic tape drive according to this embodiment includes a magnetic head 1, tape guides 2 and 3, a first reel 4, a head displacement unit 7, an operation unit 11, a control unit 12, and a recording / reproduction. A control unit 13, a displacement control unit 14, and motors 21 and 22 are provided. The second reel 5 and the magnetic tape 6 can be attached to and detached from the magnetic tape drive.

  The magnetic head 1 can record various kinds of information on the magnetic tape 6 and can reproduce various kinds of information recorded on the magnetic tape 6. The magnetic head 1 has a head block (not shown) in which an MR head unit (not shown) incorporating an MR element is arranged in a state where the magnetic tape 6 is loaded at a predetermined position in the apparatus. 6 is in contact. In the present embodiment, the magnetic head 1 is realized by an MR head including an MR element (magnetoresistance effect element), but the present invention is not limited to this.

  The tape guides 2 and 3 are respectively arranged on the first reel 4 side and the second reel 5 side of the magnetic head 1, and the winding angle of the magnetic tape 6 around the magnetic head 1 and the position in the width direction of the magnetic tape 6 are determined. It is regulated.

  The first reel 4 can wind a magnetic tape 6 drawn from a second reel 5 (described later). The first reel 4 is arranged in advance in the magnetic tape drive. The first reel 4 is rotationally driven in a direction indicated by an arrow E or G by a motor 21 that is driven and controlled by the control unit 12.

  The second reel 5 is disposed in a cartridge (not shown) that can be attached to and detached from the magnetic tape drive. The second reel 5 is mounted on a reel base (not shown) arranged in the apparatus when a cartridge (not shown) is mounted in the apparatus. The reel base is rotationally driven in a direction indicated by an arrow F or H by a motor 22 that is driven and controlled by the control unit 12. The first reel 4 rotates in the direction indicated by the arrow E and the second reel 5 rotates in the direction indicated by the arrow F, whereby the magnetic tape 6 is rotated in the direction indicated by the arrow A (first direction, forward direction). Can be transferred to. Further, the first reel 4 rotates in the direction indicated by the arrow G, and the second reel 5 rotates in the direction indicated by the arrow H, whereby the magnetic tape 6 is rotated in the direction indicated by the arrow B (second direction, reverse Direction).

  The magnetic tape 6 is a data recording magnetic tape. The magnetic tape 6 drawn out from the second reel 5 is brought into contact with the tape guide 3, the magnetic head 1, and the tape guide 2 in this order, and is wound around the first reel 4. In this embodiment, the magnetic tape 6 is realized by a magnetic tape compliant with the LTO standard, but is not limited to this.

  In this embodiment, the head displacement unit 7 is realized by a voice coil motor, but is not limited thereto. The head displacement unit 7 can displace the magnetic head 1 in the width direction of the magnetic tape 6 based on the control from the displacement control unit 14. Specifically, the head displacement unit 7 can displace the magnetic head 1 in the width direction of the magnetic tape 6 in order to perform arbitrary tracking servo. That is, the magnetic tape driving device of the present embodiment is a device that records data on the magnetic tape 6 in a format compliant with the LTO standard. Therefore, the magnetic head 1 is parallel to the width direction of the magnetic tape 6 during data recording. In order to form a plurality of tracks and to selectively trace a plurality of tracks formed in the width direction of the magnetic tape during data reproduction, the magnetic tape 6 can be displaced in the width direction.

  The operation unit 11 receives various operations such as a recording command and a stop command by the user. The operation unit 11 sends a control signal to the control unit 12 when receiving various operations by the user.

  When a control signal is sent from the operation unit 11, the control unit 12 controls the recording / playback control unit 13, the displacement control unit 14, and the motors 21 and 22 according to the content of the control signal. Specifically, the control unit 12 outputs a command signal for recording information on the magnetic tape 6 and a command signal for reading information recorded on the magnetic tape 6 to the recording / reproducing control unit 13. To do. The control unit 12 sends a command for starting or stopping the head displacement unit 7 to the displacement control unit 14. The control unit 12 sends a command for starting or stopping the operation to the motors 21 and 22.

  The controller 12 can control the tension of the magnetic tape 6 by adjusting the driving direction and driving torque of the motors 21 and 22. For example, in a state where both the motors 21 and 22 are operated and the magnetic tape 6 is transported in the direction indicated by the arrow A, the motor 21 applies a driving force to the first reel 4 in the arrow E direction, 22 applies a weak driving force in the direction of the arrow H to the second reel 5 to generate a braking force and apply tension to the magnetic tape 6. By increasing the driving force of the motor 22 in the direction of arrow H, the braking force applied to the second reel 5 is increased, and the tension of the magnetic tape 6 between the reels can be increased. Further, by reducing the driving force of the motor 22 in the direction of arrow H, the braking force applied to the second reel 5 is weakened, and the tension of the magnetic tape 6 between the reels can be reduced.

  The recording / reproducing control unit 13 causes the magnetic head 1 to perform a recording operation or a reproducing operation in accordance with a control command from the control unit 12. Specifically, the recording / reproducing control unit 13 controls the magnetic head 1 to flow a predetermined current to generate a magnetic field in the vicinity of the sliding contact portion of the magnetic head 1 with the magnetic tape 6.

  The displacement control unit 14 sends a command to the head displacement unit 7 to displace the magnetic head 1 in the width direction of the magnetic tape 6. Specifically, when the head displacement unit 7 is realized by a voice coil motor, for example, the displacement control unit 14 applies a drive current to the voice coil motor.

[3. Operation of magnetic tape drive unit]
FIG. 7A is a flowchart showing an operation when the magnetic tape 6 is shifted from the transported state to the stopped state. FIG. 7B is a flowchart showing an operation when the magnetic tape 6 is shifted from the stop state to the transfer state. FIG. 8 shows a tape drive command (a), a magnetic tape transfer speed (b), a tension control signal (when the magnetic tape 6 is changed from the transfer state to the stop state, and when the magnetic tape 6 is changed from the stop state to the transfer state). c) A change (d) in the tension of the magnetic tape 6 is shown. The tape drive command (a) includes a transfer start command and a transfer stop command for the magnetic tape 6. The tension control signal includes a command for reducing the tension of the magnetic tape 6 and a command for restoring the tension of the magnetic tape 6. T _REF in FIG. 9D is a normal tension value when data is recorded on the magnetic tape 6.

  First, the transition operation from the transfer state of the magnetic tape 6 to the stop state will be described with reference to FIGS. 7A and 8.

  When the control unit 12 controls the motors 21 and 22 to move the magnetic tape 6 in the direction indicated by the arrow A, for example, when the stop command is input to the operation unit 11, the control unit 12 stops the motors 21 and 22. An instruction is output (timing t1 in FIG. 8). As a result, the motors 21 and 22 perform a decelerating operation for gradually decreasing the rotation speeds of the first reel 4 and the second reel 5 to decrease the transfer speed of the magnetic tape 6 (step S1 in FIG. 7A).

The controller 12 measures the transfer speed every predetermined time while reducing the transfer speed of the magnetic tape 6. The transfer speed of the magnetic tape can be calculated based on the rotational torque of the motors 21 and 22, for example. Each time the controller 12 calculates the transfer speed V, the controller 12 compares the calculated transfer speed V with the reference speed V _REF . In the present embodiment, the reference speed V _REF is set to 1 m / second, for example (step S2 in FIG. 7A).

As a result of the comparison between the transfer speed V and the reference speed V _REF , the control unit 12 determines the tension of the magnetic tape 6 if the transfer speed V falls below the reference speed V _REF (YES determination in step S3, timing t2 in FIG. 8). The normal value T _REF is lowered to a predetermined value T _LOW . Specifically, the control unit 12 reduces the driving force in the direction indicated by the arrow H in the motor 22 to be lower than the driving force at the normal time (for example, during data recording), thereby reducing the braking force applied to the second reel 5. . As a result, the tension of the magnetic tape 6 between the first reel 4 and the second reel 5 decreases (step S4 in FIG. 7A; timings t2 to t3 in FIG. 8).

The controller 12 stops the transfer of the magnetic tape 6 at the timing t4 in FIG. Note that the tension of the magnetic tape 6 remains at the predetermined value T _LOW after the timing t3 in FIG.

  Next, the transition operation from the stop state to the transfer state of the magnetic tape 6 will be described with reference to FIGS. 7B and 8.

  When the transfer start command is sent from the operation unit 11 while the magnetic tape 6 is stopped, the control unit 12 controls the motors 21 and 22 to start operating (timing t5 in FIG. 8). As a result, the motor 21 rotates the first reel 4 in the direction indicated by the arrow E, and the motor 22 rotates the second reel 5 in the direction indicated by the arrow F. As the first reel 4 rotates in the direction indicated by arrow E and the second reel 5 rotates in the direction indicated by arrow F, the magnetic tape 6 is transferred in the direction indicated by arrow A. The control unit 12 performs an acceleration operation for gradually increasing the rotational speeds of the motors 21 and 22 to increase the transfer speed of the magnetic tape 6 (step S11 in FIG. 7B).

The controller 12 measures the transfer speed every predetermined time while increasing the transfer speed of the magnetic tape 6. The transfer speed of the magnetic tape can be calculated based on the rotational torque of the motors 21 and 22, for example. Each time the controller 12 calculates the transfer speed V, the controller 12 compares the calculated transfer speed V with the reference speed V _REF . In the present embodiment, the reference speed V _REF is set to 1 m / second, for example (step S12 in FIG. 7B).

When the transfer speed V exceeds the reference speed V _REF as a result of the comparison between the transfer speed V and the reference speed V _REF (YES determination in step S13, timing t6 in FIG. 8), the control unit 12 increases the tension of the magnetic tape 6. Increase from the predetermined value T _LOW to the normal value T _REF . Specifically, the control unit 12 increases the driving force in the direction indicated by the arrow H in the motor 22 and increases the braking force applied to the second reel 5 to the driving force during normal time (for example, during data recording). This increases the tension of the magnetic tape 6 between the first reel 4 and the second reel 5 (step S14 in FIG. 7B; timings t6 to t7 in FIG. 8).

As described above, in this embodiment, while the transfer speed V of the magnetic tape 6 is lower than the reference speed V _REF (including the stop state), the tension of the magnetic tape 6 is changed from the normal value T _REF to the predetermined value T _LOW. To lower. By reducing the tension of the magnetic tape 6, the spacing between the magnetic head 1 and the magnetic tape 6 can be increased.

  As shown in FIG. 2A, by increasing the spacing SP1, meniscus portions (104a, 104b, etc.) generated between the magnetic head 1 and the surface of the magnetic layer 102 in the low spacing state shown in FIG. 2B. Compared to the meniscus portion, it can be reduced. By reducing the meniscus portion, the adhesion force (for example, arrows C1 and C2) generated between the magnetic head 1 and the magnetic tape 100 can be reduced, and sticking of the magnetic tape 100 to the magnetic head 1 can be reduced. Can do.

  Further, by increasing the spacing SP1 as shown in FIG. 2A, it is possible to reduce the contact pressure applied to the portion of the magnetic tape 100 that is in contact with the magnetic head 1 when the magnetic tape 6 is stopped. . By reducing the contact pressure, the pressure applied to the lower layer 101 (see FIG. 1) of the magnetic tape 100 can be reduced, so that the amount of the lubricant 104 that exudes from the lower layer 101 can be reduced. Therefore, sticking of the magnetic tape 100 to the magnetic head 1 can be reduced.

[4. Example〕
The present inventors conducted a durability test under various conditions using a magnetic tape compliant with the LTO standard manufactured by Hitachi Maxell. For example, as shown in FIG. 6, the magnetic tape used in the experiment is provided with a lower layer of 1.0 μm thickness and an upper layer of 0.1 μm thickness on one surface of a base film having a thickness of 5 μm. A back coat layer having a thickness of 0.5 μm is provided on the surface. A surface lubricant layer having a thickness of 4 nm is provided on the upper layer. The spacing between the upper layer and the magnetic head is 18 nm.

  The magnetic tape having such a configuration was loaded into a predetermined test apparatus, and the adhesion of the magnetic tape to the magnetic head was measured. Note that the test apparatus includes, for example, an LTO drive, a magnetic head, a plurality of guide rollers, and a tension probe. The tension probes are arranged on the entrance side and the exit side of the magnetic head on the tape path, respectively, and the state of the magnetic tape sticking to the magnetic head is determined based on the difference in tension of the magnetic tape detected by each tension probe. To detect.

  The test apparatus is loaded with a predetermined magnetic tape, the magnetic tape is decelerated from the transfer speed at the time of data recording, and when the transfer speed reaches 1 m / sec, the driving force of the motor that drives the reel is adjusted, The brake force applied to the reel was adjusted to reduce the magnetic tape tension. Specifically, the motor reduces the driving force applied to the upstream reel in the magnetic tape transfer direction in the direction opposite to the magnetic tape transfer direction, thereby reducing the braking force applied to the upstream reel. The magnetic tape tension was reduced.

  The measurement of the state of sticking of the magnetic tape to the magnetic head is carried out by restarting the transfer of the magnetic tape when 10 minutes have passed since the magnetic tape was stopped, and the magnetic tape being stuck to the magnetic head at the time of the restart. The presence or absence was measured. The presence or absence of sticking is determined by measuring the friction in the magnetic head based on the difference in tension that can be detected by the tension probe arranged on the magnetic head inlet side and the tension probe arranged on the magnetic head outlet side in the above-described test apparatus. The presence or absence of attachment was judged. For example, when the tension on the magnetic head entrance side and the tension on the magnetic head exit side are substantially the same, it is determined that there is no sticking because the friction between the magnetic head and the magnetic tape is low. If the tension on the magnetic head entrance side is lower than the tension on the magnetic head exit side, it is determined that sticking has occurred because the friction between the magnetic head and the magnetic tape is high. More specifically, the difference between the tension on the magnetic head entrance side and the tension on the magnetic head exit side is compared with a predetermined value, and if the difference exceeds the predetermined value, it is determined that sticking has occurred.

  As shown in Table 1, the tension of the magnetic tape was set in the range of 0.6 N (Example 1) to 0.1 N (Example 6) in increments of 0.1 N. The tension at the time of data recording or reproduction with respect to the magnetic tape is, for example, 0.7 N when the LTO4 drive is used. The results measured based on these conditions are shown in (Table 1).

(Table 1) shows the results of testing under conditions included in the scope of application of the present embodiment. In this embodiment, as shown in Examples 1 to 6 of (Table 1), the test was performed while controlling the tension of the magnetic tape. As shown in Examples 2 to 5, the tension was 0.2 to 0. In the range of 0.5 N, no sticking of the magnetic tape to the magnetic head was observed. However, when the tension of the magnetic tape was 0.6 N (Example 1), the magnetic tape was attached to the magnetic head. On the other hand, when the tension of the magnetic tape becomes 0.1 N (Example 6), the tension is too low, and the magnetic tape gets over the flange of the tape guide (for example, tape guides 2 and 3 shown in FIG. 1), and from the tape guide. I dropped out.

Therefore, the predetermined value T _LOW of the tension of the magnetic tape in the present embodiment is preferably in the range of about 0.2 to 0.5N when the tension during recording / reproduction is 0.7N. That is, it is preferable that the recording / reproducing ratio of the magnetic tape tension in this embodiment (ratio to the tension during recording / reproducing) is approximately 0.3 to 0.8 times (30 to 80%). In Table 1, the recording / reproduction time ratio shown in Example 5 is “0.29”, but is included in the preferable numerical range “0.3 to 0.8” in the present embodiment.
[5. Effects of the embodiment, etc.]
According to the present embodiment, when the magnetic tape 6 is stopped from the state of being transferred, if the transfer speed V of the magnetic tape 6 decreases to the reference speed V _REF , the tension of the magnetic tape 6 is changed from the normal value T _REF. By lowering to a predetermined value T _LOW , the spacing between the magnetic head 1 and the magnetic tape 6 can be increased. By increasing the spacing, the meniscus portion generated between the magnetic head 1 and the magnetic tape 6 can be reduced when the magnetic tape 6 is stopped. By reducing the meniscus portion, friction between the magnetic head 1 and the magnetic tape 6 can be reduced, and sticking when resuming transfer can be reduced.

Further, by reducing the tension of the magnetic tape 6 from the normal value T _REF to the predetermined value T _LOW , the contact pressure applied to the magnetic tape 6 can be reduced when the magnetic tape 6 is stopped. By reducing the contact pressure, the amount of lubricant that oozes out from the lower layer of the magnetic tape 6 can be reduced, and the meniscus portion generated at the interface between the magnetic head 1 and the magnetic tape 6 can be reduced. By reducing the meniscus portion, friction between the magnetic head 1 and the magnetic tape 6 can be reduced, and sticking when resuming transfer can be reduced.

  Further, according to the present embodiment, it is not necessary to add hardware in order to reduce the tension of the magnetic tape. This can be realized only by changing the control program (firmware) of the motors 21 and 22 in the control unit 12. Therefore, it can be realized at low cost.

  In the present embodiment, it has been described that the magnetic tape 6 is prevented from sticking to the magnetic head 1 when the magnetic tape 6 is stopped from the transfer state. However, the transfer direction of the magnetic tape 6 is reversed from the stop state. Thus, even when the transfer is resumed, it is possible to reduce the sticking of the magnetic tape 6 to the magnetic head 1. That is, in FIG. 5, when the magnetic tape 6 is moved in the direction indicated by the arrow A and stopped, and then transferred in the direction indicated by the arrow B, the magnetic tape 6 is prevented from sticking to the magnetic head 1. can do.

The magnetic head 1 in the present embodiment is an example of the magnetic head unit of the present invention. The motors 21 and 22 in the present embodiment are an example of the tape transport means of the present invention. The control unit 12 in the present embodiment is an example of the control unit of the present invention. The reference speed V _REF of the magnetic tape in the present embodiment is an example of the reference speed of the present invention. The predetermined tension value T _LOW in the present embodiment is an example of the predetermined tension value of the present invention. The tension reference value T _REF in the present embodiment is an example of the tension value of the magnetic tape at the time of recording / reproducing of the present invention.

  The magnetic tape drive of the present invention is useful for an apparatus that uses a magnetic tape as an information medium. In particular, it is useful for a magnetic tape drive capable of linearly recording data on a computer tape.

DESCRIPTION OF SYMBOLS 1 Magnetic head 12 Control part 13 Recording / reproducing control part 14 Displacement control part 21 and 22 Motor

Claims (7)

A magnetic head unit having a magnetic head capable of recording or reproducing information by sliding on a magnetic tape;
A magnetic tape drive comprising a tape transfer means for transferring the magnetic tape,
When the magnetic tape is moved from the transfer state to the stop state, the tape transfer means is configured to reduce the tension of the magnetic tape to a predetermined value when detecting that the transfer speed of the magnetic tape is lower than a reference speed. A magnetic tape drive having a control unit for controlling. A magnetic head unit having a magnetic head capable of recording or reproducing information by sliding on a magnetic tape;
A magnetic tape drive comprising a tape transfer means for transferring the magnetic tape,
When the magnetic tape is moved from the stop state to the transfer state, the tape transfer means is controlled so as to reduce the tension of the magnetic tape to a predetermined value while the transfer speed of the magnetic tape is lower than the reference speed. The magnetic tape drive device provided with the control part to perform.   The magnetic tape driving device according to claim 1, wherein the reference speed is 1 m / sec.   3. The magnetic tape drive device according to claim 1, wherein the control unit controls the tape transfer unit so that the tension of the magnetic tape becomes the predetermined value while stopping the transfer of the magnetic tape.   2. The magnetic tape driving device according to claim 1, wherein the predetermined value is 30 to 80% of the tension value of the magnetic tape during recording and reproduction. Magnetic tape for transporting the magnetic tape in a magnetic tape drive device comprising a magnetic head unit having a magnetic head capable of recording or reproducing information by sliding on the magnetic tape and a tape transport means for transporting the magnetic tape A driving method comprising:
A method of driving a magnetic tape, wherein when the magnetic tape is moved from a transported state to a stopped state, if it is detected that the transport speed of the magnetic tape is lower than a reference speed, the tension of the magnetic tape is decreased. Magnetic tape for transporting the magnetic tape in a magnetic tape drive device comprising a magnetic head unit having a magnetic head capable of recording or reproducing information by sliding on the magnetic tape and a tape transport means for transporting the magnetic tape A driving method comprising:
A method of driving a magnetic tape, wherein when the magnetic tape is moved from a stopped state to a running state, the tension of the magnetic tape is reduced while the transfer speed of the magnetic tape is lower than a reference speed.

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