JP2003132602A - Tape drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tape drive wherein the number of teeth for a drive gear is reduced. SOLUTION: A drive hub is rotary-driven on a predetermined axis by a supply reel motor for driving the supply reel of a tape cartridge. A rotating force is transmitted to the supply reel, which is accompanied by movement in one direction on the predetermined axis of a drive gear engaged with the drive hub in a rotational direction. The drive gear has a contact part 124a formed in each of three places around the predetermined axis and abutted on the drive hub during the movement in one direction on the predetermined axis, and an integral multiple of 3, e.g. three teeth 123a, to engage the supply reel in the rotational direction. These teeth are formed in positions corresponding to the contact parts.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a DLT (Digital Li
The present invention relates to a magnetic recording / reproducing apparatus such as a linear tape storage system represented by near tape) or LTO (Linear Tape Open), and particularly to a tape drive for driving a tape cartridge.

[0002]

2. Description of the Related Art This kind of linear tape storage system (magnetic recording / reproducing apparatus) has been developed as a backup for computer systems, and various types have been conventionally proposed. For example, a digital linear tape drive as a DLT is disclosed in Japanese Patent Laid-Open No. 9-198639.

A digital linear tape drive (hereinafter, also simply referred to as "drive device", "tape drive", or "drive") is a tape cartridge having a single reel (supply reel) (hereinafter, simply "cartridge"). It is intended to receive, and has a built-in take-up reel inside. When the tape cartridge is mounted on the drive device, the magnetic tape is pulled out from the tape cartridge and wound on the take-up reel via the head guide assembly (HGA). The head guide assembly is for guiding the magnetic tape (hereinafter, also simply referred to as “tape”) pulled out from the tape cartridge to the magnetic head. The magnetic head exchanges information with the tape. The head guide assembly generally consists of an aluminum plate in the shape of a boomerang and six large guide rollers using bearings.

Incidentally, the head guide assembly is also called a tape guide assembly, and it is, for example, a table 9
It is disclosed in Japanese Patent Laid-Open No. -500573. An example of the guide roller is disclosed in Japanese Patent Laid-Open No. 2000-100025.

In general, a tape drive includes a substantially rectangular parallelepiped housing having a common base, as described in, for example, Japanese Patent Publication No. 2000-501547. The base has two spindle motors (reel motors). The first spindle motor is a spool (take-up reel) permanently attached to the base.
And the spool is sized to receive a relatively fast flowing magnetic tape. The second spindle motor (reel motor) is adapted to receive a removable tape cartridge. The first spindle motor (reel motor) is called a take-up reel motor, while the second spindle motor (reel motor) is called a supply reel motor. The removable tape cartridge is manually or automatically inserted into the drive through a slot formed in the drive housing. When the tape cartridge is inserted into the slot, the cartridge engages a second spindle motor (reel motor). Prior to rotating the first and second spindle motors (reel motors), a mechanical buckling mechanism connects the tape cartridge to a permanently mounted spool (take-up reel). Many rollers (guide rollers) located between the tape cartridge and the permanent spool guide it as the magnetic tape moves back and forth at a relatively high speed between the tape cartridge and the permanently mounted spool. To do.

The digital linear tape drive having such a structure requires a device for the take-up reel to pull the tape from the supply reel. Such a pulling device is disclosed in, for example, Japanese Patent Publication No. 3-7595. According to this publication, take-up reel means is connected to take-up leader means (first tape leader), and supply tape leader means (second tape leader) is fixed to the tape on the supply reel. The first tape leader has a tab at one end, the second tape leader has a locking hole, and the tab is engaged with the locking hole.

Further, a mechanism for joining the first tape leader to the second tape leader is also required. Such a joining mechanism is disclosed in, for example, Japanese Patent Publication No. 6-39027.

Further, in Japanese Unexamined Patent Publication No. 2000-100116, the end portion of the leader tape is attached to the tape end of the tape cartridge without the need for an ear piece protruding laterally of the leader tape (second tape leader). A "locking part structure of a leader tape" that can be locked to a hooking part is disclosed.

Japanese Unexamined Patent Publication No. 11-86381 discloses a lock system for preventing the take-up reel of the tape drive from rotating when the tape cartridge is not inserted in the drive.

The tape drive further includes a tape head actuator assembly, which is positioned on the tape path defined by the plurality of rollers between the take-up spool and the tape cartridge. In operation, the magnetic tape flows back and forth between the take-up spool and the tape cartridge and closely approaches the head actuator assembly while flowing on the defined tape path. An example of such a head actuator assembly is disclosed in the above Japanese Patent Publication No. 2000-501547.

On the other hand, an example of a tape cartridge to be mounted on a digital linear tape drive is disclosed in Japanese Patent Laid-Open No.
No. 000-149491.

Further, Japanese Unexamined Patent Publication No. 11-316991 discloses a "tape drive" in which a tape leader can be pushed from a tape cartridge to a take-up reel without using a buckling mechanism or a take-up leader. There is.

As mentioned above, the tape drive is the first
And a second reel motor (ie, a take-up reel motor and a supply reel motor), which are mounted on the chassis (specifically, on the back surface of the chassis). An inner rotor type motor is generally used as the first and second reel motors. Further, after the tape cartridge containing the supply reel is inserted into the slot of the tape drive, it is necessary to engage the supply reel with the supply reel motor in order to drive the supply reel to rotate. Such an engaging operation is called "loading" in this technical field, and a mechanism for engaging is called a "loading mechanism". More specifically, as disclosed in Japanese Patent Laid-Open No. 2000-149491, the rotation driving surface (reel hub) of the supply reel is exposed from the bottom surface of the tape cartridge to the outside. on the other hand,
The loading mechanism has a drive gear attached to a rotary shaft of a rotor of a supply reel motor so as to be vertically movable. When the tape cartridge is inserted into the slot of the tape drive, the loading mechanism is activated and the drive gear moves up from the bottom surface of the chassis. This allows
The drive gear engages the reel hub of the cartridge,
The supply reel motor is ready to rotate the supply reel.

The tape cartridge and the drive gear will be briefly described with reference to FIGS. 1 and 2. The tape cartridge 1 has a reel hub or spindle 2 connected to one end of a supply reel. Spindle 2
Has a large number of teeth 3 arranged in the circumferential direction, for example, 48 teeth 3. Each tooth 3 extends in the radial direction. On the other hand, the drive gear 4 has the same number as the teeth 3 of the spindle 2, that is, 4
It has eight teeth 5 arranged in the circumferential direction and a plurality of contact portions 6 for restricting the movement of the drive gear 4 by coming into contact with other members. Each tooth 5 also extends in the radial direction. The teeth 5 of the drive gear 4 mesh with the teeth 3 of the tape cartridge 1. The meshing of these teeth 3, 5 can be kept in an appropriate state because the movement of the drive gear 4 is restricted by the contact portion 6.

[0015]

However, the number of the teeth 5 of the drive gear 4 is as many as 48, and the teeth 5 are large.
Since each of these requires high accuracy, the following problems occur. The mold for manufacturing the drive gear 4 is expensive, and its accuracy is difficult to measure.
Since the teeth randomly mesh each time the tape cartridge is loaded, the spindle 2 of the cartridge 1 may shake.

Therefore, an object of the present invention is to provide a tape drive capable of reducing the number of teeth of a drive gear.

[0017]

According to the present invention, the supply reel motor (60) for driving the supply reel of the tape cartridge (1) and the supply reel motor are rotationally driven on a predetermined axis. Drive hub (1
10) and a drive gear (120) that is movable along the predetermined axis, engages with the drive hub in the rotational direction, and transmits the rotational force to the supply reel with movement to one side on the predetermined axis. ) And, the drive gear,
Contact portions (124a) that are respectively formed at three locations around the predetermined axis and come into contact with the drive hub when moving to one side on the predetermined axis, and 3 for engaging the supply reel in the rotation direction. Number of teeth (123a, 1
23b) and the teeth are formed at the positions corresponding to the contact portions.

The number of teeth may be three.

The number of teeth may be six.

The reference numerals in the above parentheses are given to facilitate understanding of the present invention, and are of course only examples and are not limited to these.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION A tape drive according to an embodiment of the present invention will be described with reference to FIGS.

A tape drive is designated by the reference numeral 10,
It has a chassis 20 having an upper surface 20U and a lower surface 20L. The chassis 20 is a sheet metal press chassis made of an iron-based magnetic material. The upper surface 20U is divided into a first upper region 20U1 and a second upper region 20U2. Similarly, the lower surface 20L is divided into a first lower area 20L1 and a second lower area 20L2 that face the first upper area 20U1 and the second upper area 20U2, respectively. In addition, the chassis 20 includes a first upper region 20U1.
The first opening 20a1 is formed in the (first lower region 20L1), and the second opening 20a2 is formed in the second upper region 20U2 (second lower region L2). The first opening 20a has a disc shape. The second opening 20a2 is
It has a cylindrical shape formed by bending the chassis 20 (second upper region 20U2) downward.

The tape drive 10 further includes a take-up reel 30, a first reel motor 40, a slot portion 50, and a second reel motor 60. The first reel motor 40 is called a take-up reel motor, and the second reel motor 60 is called a supply reel motor.

The take-up reel 30 is a chassis 20.
Is rotatably mounted on the first upper region 20U1. The first reel motor (take-up reel motor) 40 has a rotor (described later) portion on the first lower region 20L2 side of the chassis 20, and a first opening 20.
The motor is attached to the take-up reel 30 so as to project from the a1 and rotationally drives the take-up reel 30.
The first reel motor 40 is fixed to the first motor board 41 made of a magnetic material, the first rotor 42 rotatably mounted on the first motor board 41, and the first motor board 41. And the installed first stator 43. The first reel motor 40 is an inner rotor type motor in which the first rotor 42 is arranged inside, and the first rotor 42 has a first magnet 421.

On the other hand, the slot portion 50 is provided on the second upper region 20U2 of the chassis 20, and the slot portion 50 has a rotatable supply reel (not shown).
A cartridge (not shown) provided with is inserted. Second
Of the reel motor (supply reel motor) 60 is attached to the second lower region 20L2 side of the chassis 20 in a state in which a portion of the rotation shaft of the rotor (described later) is inserted into the second opening 20a2. It is a motor for rotationally driving the supply reel when the cartridge is inserted into the slot 50. The second reel motor 60 includes a second motor substrate 61 made of a magnetic material,
It has a second rotor 62 rotatably mounted on the second motor substrate 61, and a second stator 63 fixedly installed on the second motor substrate 61. Similarly to the first reel motor 40, the second reel motor 60 has a second reel motor 60.
Is an inner rotor type motor in which the rotor 62 of FIG.
21.

The first reel motor (take-up reel motor) 40 and the second reel motor (supply reel motor) 60 have a common structure. That is, in the first reel motor 40, the first rotor 42 and the first rotor 42
Is arranged on the upper surface side of the first motor board 41, and similarly, in the second reel motor 60, the second rotor 62 and the second stator 63 are arranged in the second side.
Is arranged on the upper surface side of the motor board 61. Therefore, in both the first reel motor 40 and the second reel motor 60, the first magnet 421 that forms the first rotor 42 and the second magnet that forms the second rotor 62.
The magnet 621 is exposed to the outside.

Both the first magnet 421 and the second magnet 621 are made of a magnetic material such as the chassis 20.
Since it is covered with, magnetic leakage can be blocked.

According to the tape drive 10 having such a structure, information can be exchanged by the magnetic head 80 with respect to the magnetic tape (not shown) which is pulled out from the supply reel and wound on the take-up reel 30. .

Next, the loading mechanism 100 will be described. The loading mechanism 100 includes the supply reel motor 60 and the lower surface 20L of the chassis 20 (second lower region 2).
0L2).

The supply reel motor 60 has a rotation shaft 611 fixed to the second motor substrate 61 so as to stand vertically from the substantial center thereof. The second rotor 62 is rotatably supported on the rotating shaft 611 via a ball bearing 612. That is, the second rotor 62 includes the rotating tubular body 622 attached to the ball bearing 612.
And a dish-shaped rotating body 623 that extends from the lower end of the rotating tubular body 622 at right angles to the extending direction of the rotating shaft 611, and has an outer peripheral end bent upward at a right angle, and the dish-shaped rotating body 623. The ring-shaped second magnet 621 is fixedly attached to the outer peripheral surface of the outer peripheral end of the rotating body 623.

On the other hand, the second stator 63 is located close to the outer peripheral side of the second magnet 621, and the second motor substrate 61.
As shown in FIG. 2, it is arranged on the upper side and has a plurality of radially extending stator cores and a stator coil wound around each of the plurality of stator cores.

The loading mechanism 100 has a drive hub 110 fixedly installed by three screws on the upper end of the rotary tubular body 622 of the rotor 62. Therefore, the drive hub 110 rotates with the rotor 62 around a predetermined axis with respect to the rotation axis 611.

The drive hub 110 will be described with reference to FIG. 9 as well. The drive hub 110 has a substantially annular shape, and its outer peripheral end is bent downward. That is,
The drive hub 110 includes an annular portion 111 that extends in parallel with the second motor substrate 61 and is fixed to the upper end of the rotating tubular body 622, and is bent at a right angle downward from the outer peripheral end of the annular portion 111. And a tubular portion 112. The outer peripheral wall of the cylindrical portion 112 is vertically spaced at intervals of 120 ° (that is,
Three engagement grooves 112a extending in the direction in which the rotating shaft 611 extends) are formed. Further, at the lower end of the tubular portion 112, contact portions 112b are formed by three grooves at 120 ° intervals between the three engagement grooves 112a.
In other words, the three contact portions 11 of the drive hub 110
Each of the two 2b is arranged between the three engaging grooves 112a that are adjacent to each other in the circumferential direction.

A drive gear 120 is arranged on the outer periphery of the drive hub 110. The drive gear 120 has a substantially double cylindrical shape. That is, the drive gear 120 includes an inner cylindrical portion 121, an outer cylindrical portion 122 arranged at a predetermined distance from the inner cylindrical portion 121, and an inner cylindrical portion 12.
1 and the outer cylindrical portion 122, and an annular portion 123 that joins at the upper end. Therefore, the drive gear 120
Has a cylindrical groove 120a formed between the inner cylindrical portion 121 and the outer cylindrical portion 122. A spring 130 is arranged in the cylindrical groove 120a, and the spring 130 constantly urges the drive gear 120 upward.

The drive gear 120 will be further described with reference to FIGS. 10 and 11. Inner cylindrical portion 121
The inner peripheral wall of the drive hub 110 is formed with three rod-shaped projections 121a which are inserted into the three engagement grooves 112a of the drive hub 110 and extend in the vertical direction. Thus, the drive gear 120 is vertically movable along a predetermined axis and is rotationally engaged with the drive hub 110.

The drive gear 120 has an inner annular flange 124 formed so as to project inward at the lower end of the inner cylindrical portion 121, and an outer side formed so as to project outward at the lower end of the outer cylindrical portion 122. And an annular flange 125. On the upper end of the inner annular flange 124, a contact portion 124a is formed by three protrusions at a position corresponding to the contact portion 112b of the drive hub 110. In other words, each of the three contact portions 124a of the drive gear 120 is arranged between the three rod-shaped protrusions 121a that are adjacent to each other in the circumferential direction. Therefore, when the drive gear 120 is moved upward as shown in FIG. 8, the three contact portions 124a of the drive gear 120 come into contact with the three contact portions 112b of the drive hub 110. In this way, the contact between the contact portion 124a and the contact portion 112b limits the upward movement of the drive gear 120 to determine the height.

Further, the annular portion 1 of the drive gear 120
Three teeth 123 a are formed on the upper surface of 23. Each tooth 123a extends in the radial direction at a position corresponding to the contact portion 124a on a one-to-one basis. Thus, when the drive gear 120 is moved upward as shown in FIG. 8, the three teeth 123a rotationally engage the teeth (see FIG. 1) of the reel hub or spindle of the tape cartridge, and the cartridge supply Rotational force is transmitted to the reel.

Since the drive gear 120 has a small number of teeth 123a, a mold used for manufacturing can be provided at low cost, and the accuracy of the mold can be easily measured, so that the quality can be easily guaranteed. In addition, the teeth 123 are provided at positions corresponding to the contact portions 124a that contribute to the height determination of the drive gear 120.
Since a is provided, the position of the tooth 123a is stable, and thus the spindle of the tape cartridge is stably rotated, so that fluctuations in the width direction of the tape can be significantly reduced.

Next, a lifting control mechanism for controlling the lifting operation of the drive gear 120 will be described.

When the loading mechanism 100 is not in operation, as shown in FIG.
0 is stored in the second opening 20a2,
In the operating state, as shown in FIG.
It is in a state of protruding upward from the lower surface 20L of 0. That is,
The loading mechanism 100 includes a lift control mechanism (which will be described in detail later) for controlling the lift operation of the drive gear 120. To briefly describe here, the lifting control mechanism is provided when the loading mechanism 100 is not in operation.
As shown in FIG. 7, in order to bring the drive gear 120 into the housed state, the drive gear 120 is controlled so as to be located below it against the biasing force of the spring 130. On the other hand, when the loading mechanism 100 is in operation, the elevating control mechanism controls the spring 130 as shown in FIG.
The drive gear 120 is controlled to be positioned upward by utilizing the urging force of.

The elevating control mechanism of the loading mechanism 100 includes a second stator 63 of the supply reel motor 60,
The rotation shaft 611 covers the second magnet 621 of the second rotor 62 and the outer peripheral end of the dish-shaped rotating body 623.
It has a ring cam 140 rotatably arranged around the. More specifically, the ring cam 140 is arranged so as to be separated from the upper surface of the second stator 63, the second magnet 621 of the second rotor, and the outer peripheral end of the dish-shaped rotating body 623 by a predetermined distance. An annular member 141,
The inner peripheral side cylindrical member 1 is bent downward at a right angle from the inner peripheral edge of the annular member 141 and is arranged at a predetermined distance from the outer peripheral end of the dish-shaped rotating body 623 of the second rotor 62.
42, and an outer peripheral side cylindrical member 143 that is bent downward at a right angle from the outer peripheral edge of the annular member 141 and is arranged at a predetermined distance from the outer peripheral end of the second stator 63. A gear portion (not shown) that engages with a gear not shown is formed on a part of the outer peripheral side cylindrical member 143. On the inner peripheral wall of the inner peripheral side cylindrical member 142, as shown in FIG. 3, three cam grooves 142a obliquely extending from the lower end to the upper end (however, only two are shown in FIG. 3).
Are formed. The three cam grooves 142a are
They are arranged so as to be rotationally symmetrical with respect to the rotating shaft 611 with an angular interval of 120 ° therebetween.

Further, the annular member 14 of the ring cam 140
1, three arc-shaped openings 141a are formed symmetrically around the rotary shaft 611 at equal angular intervals of 120 °. On the other hand, in the second lower region 20L2 of the chassis 20, at a position corresponding to these three arc-shaped openings 141a, 120 °
Guide pins 14 symmetrically arranged at equal angular intervals
5 are provided. These three guide pins 145 are inserted into the corresponding three arc-shaped openings 141a.

As described above, the cylindrical second opening 2
A second upper region 20U2 of the chassis 20 is bent downwards to form a cylindrical member 150 to form 0a2. In other words, the cylindrical member 150 is formed using a part of the chassis 20. The cylindrical member 150 is arranged close to the inner peripheral wall of the inner peripheral side cylindrical member 142 of the ring cam 140. The cylindrical member 150 has a rotating shaft 61 at an equal angular interval of 120 °.
Three elongated holes or guide slits 150a that are long in the up-down direction parallel to 1 are formed.

A drive ring 160 is arranged so as to be vertically movable (movable up and down) so as to be in sliding contact with the inner peripheral wall of the cylindrical member 150. The drive ring 160 has 120 ° at a position corresponding to the three guide slits 150a.
3 extending radially outward (radially) at equal angular intervals
Three rod-shaped engagement pins 161 (however, only two are shown in FIG. 3) are attached. The radially outer ends of these three engagement pins 161 have three cam grooves 142a formed in the inner peripheral side cylindrical member 142 of the ring cam 140.
Respectively engaged with.

As shown in FIG. 7, the drive gear 12
When 0 is accommodated in the second opening 20a2, the three engagement pins 161 are located on the lower end side of the three cam grooves 142a. On the other hand, as shown in FIG. 8, when the drive gear 120 is operated, the three engagement pins 161 are
Is located on the upper end side of the three cam grooves 142a.

Further, the drive ring 160 has a hook portion 162 having an L-shaped cross section which protrudes from the upper end toward the inner peripheral side, and the hook portion 162 engages with the outer annular flange 125 of the drive gear 120. ing. Therefore, it is understood that the position of the drive gear 120 is regulated by the position of the drive ring 160.

A modified example of the drive gear 120 will be described with reference to FIGS. 12 and 13. 10 and 11
The same parts as those in are denoted by the same reference numerals, and the description thereof will be omitted.

Drive gear 12 shown in FIGS. 12 and 13.
0, the three teeth 12 are formed on the upper surface of the annular portion 123.
In addition to 3a, another three teeth 123b are formed. That is, a total of six teeth 123a and 123b are formed on the annular portion 123 of the drive gear 120. Each of the added teeth 123b is formed between the three teeth 123a provided at a position corresponding to the contact portion 112b and at a position corresponding to the three rod-shaped protrusions 121a in a one-to-one manner, and extends in the radial direction. .

When this drive gear 1202 is used,
When moved upward as shown in FIG. 8, a total of six teeth 123a and 123b are rotationally engaged with the teeth (see FIG. 1) of the reel hub or spindle of the tape cartridge. In this way, the rotational force is transmitted to the supply reel of the cartridge via the drive gear 120.

Although the present invention has been described above with reference to the preferred embodiments, it goes without saying that the present invention is not limited to the above-mentioned embodiments. For example, although the drive gear having three or six teeth has been described above,
If the number of teeth is an integer multiple of 3, then another number such as 9 or 12
It may be an individual.

[0051]

As described above, according to the present invention,
A tape drive that can reduce the number of teeth of a drive gear can be provided.

[Brief description of drawings]

FIG. 1 is a perspective view of a general tape cartridge as viewed from a lower surface side.

FIG. 2 is a plan view of a drive gear used in a conventional tape drive.

FIG. 3 is a plan view of the tape drive according to the embodiment of the present invention.

4 is a cross-sectional view taken along line IV-IV of FIG.

5 is an exploded perspective view showing the internal mechanism of the tape drive of FIG. 3 as viewed from the upper surface side.

6 is an exploded perspective view showing a loading mechanism provided in the tape drive of FIG. 3 as viewed from the lower surface side.

FIG. 7 is a cross-sectional view showing an enlarged state of a part of the tape drive of FIG. 3 when the drive gear is housed.

FIG. 8 is a cross-sectional view showing an enlarged state of a part of the tape drive of FIG. 3 when a drive gear is operating.

9 is a perspective view of the drive hub provided in the loading mechanism of FIG. 6 viewed from the lower surface side.

10 is a perspective view of the drive gear provided in the loading mechanism of FIG. 6 as seen from the upper surface side.

11 is a plan view of the drive gear shown in FIG.

FIG. 12 is a perspective view of a modified example of the drive gear viewed from the upper surface side.

13 is a plan view of the drive gear shown in FIG. 12. FIG.

[Explanation of symbols]

10 tape drive 20 chassis 20U upper surface 20L lower surface 30 take-up reel 40 first reel motor (take-up reel motor) 41 motor substrate 42 rotor 421 magnet 43 stator 50 slot portion 60 second reel motor (supply reel motor) 61 motor Substrate 62 Rotor 621 Magnet 63 Stator 100 Loading mechanism 110 Drive hub 111 Annular part 112 Cylindrical part 112a Engagement groove 112b Contact part 120 Drive gear 121 Inner cylindrical part 122 Outer cylindrical part 123 Annular part 121a Rod-shaped projection part 124 Inner annular flange 125 Outer annular flange 124a Contact portions 123a, 123b Teeth 130 Spring 140 Ring cam 141a Arc opening 142a Engaging groove 150 Cylindrical member 150a Guide hole 60 drive ring 161 engages pin

Claims (3)

[Claims] 1. A supply reel motor for driving a supply reel of a tape cartridge, a drive hub rotatably driven on a predetermined axis by the supply reel motor, and a drive movable along the predetermined axis. A drive gear that is rotationally engaged with the hub and that transmits a rotational force to the supply reel with movement to one side on the predetermined axis, the drive gear being provided at three locations around the predetermined axis. Each of which has a contact portion formed to abut against the drive hub when moving to one side on the predetermined axis, and an integer multiple of 3 teeth for engaging the supply reel in the rotation direction, The tape drive, wherein the teeth are formed at positions corresponding to the contact portions. 2. The tape drive according to claim 1, wherein the number of teeth is three. 3. The tape drive according to claim 1, wherein the number of teeth is six.