JP4403184B2 - Head assembly drive mechanism, head holder, magnetic head tester and magnetic disk tester - Google Patents

Description

  The present invention relates to a head assembly driving mechanism, a head holder, a magnetic head tester, and a magnetic disk tester, and more specifically, a magnetic head that controls a magnetic head to an ON track state in accordance with a servo signal set for a track on the magnetic disk. In a tester or a magnetic disk tester, a head assembly (suspension spring + magnetic head member) that supports a magnetic head via a spring is dynamically shaken using elastic deformation of the member in order to move the magnetic head in the cross-track direction. The present invention relates to a head assembly driving mechanism that can reduce the mass of the movable part of the head assembly and thereby improve the response speed of the magnetic head in the ON track control.

As the recording density of the magnetic disk device is improved, the track width of the magnetic disk is narrowed. Therefore, in the magnetic head tester or the magnetic disk tester, further improvement in head positioning accuracy is required. In addition, the rotational speed of the disk is changed from 5400 rpm to 7000 rpm to 15000 rpm, and a disk with a higher rotational speed is now in practical use.
In view of this, there is an invention of Japanese Patent Application Laid-Open No. 2003-272326 in which the piezo actuator is provided between the suspension spring and the head carriage and the head assembly is driven by the piezo actuator in accordance with a servo signal (Patent Document 1).
According to the present invention, a light-weight head cartridge holding a head assembly is dynamically moved in response to a servo signal with respect to a magnetic head (hereinafter referred to as a head) positioned on a predetermined track, or the head assembly is moved within the head cartridge. The head is dynamically moved (rotated) in accordance with the servo signal, and the deviation amount of the head from the track center is corrected by a minute movement. The minute movement is, for example, a movement of a head of several μm at a high speed with respect to the track, whereby the head moves on the track or at a predetermined speed on the track with high speed and high accuracy according to the servo signal. The position is corrected so as to be in the position ON track state.
JP 2003-272326 A

In one embodiment of the invention disclosed in Japanese Patent Application Laid-Open No. 2003-272326, a head cartridge is mounted on a micropositioning piezo stage, and the head cartridge is micro-moved to first position the head on track. Further, the head assembly provided in the head cartridge is dynamically rotated according to the servo signal to servo-control the head position in the ON track state.
The head assembly is pivotally supported by a cylindrical member and is rotated by a piezo actuator about the rotation axis of the cylindrical member. The piezo actuator only needs to perform a minute movement with respect to the head so as to correct the amount of deviation of the head from the track center. Therefore, the rotation mechanism of the head assembly enables high-speed response of the head to servo signals.
However, when the number of tracks is several thousand / inch or more as in the present, the head assembly rotation mechanism is required to have higher precision servo control and high-speed head movement. In response to this requirement, the above-described method of rotating the head assembly around the rotation axis has a large rotating part mass, so the disk rotates once after the head is displaced until it is corrected to the ON track state. There is a problem that it takes time to read / write test data. Therefore, there is a demand for further improving the response speed of the head in the ON track control.

SUMMARY OF THE INVENTION An object of the present invention is to meet such a demand, and it is possible to drive the head assembly at high speed by reducing the mass of the movable part by swinging the head assembly so that the head moves in the track crossing direction. Another object of the present invention is to provide a head assembly driving mechanism or a head holder that can improve the response speed of the head in ON track control.
Another object of the present invention is to provide a magnetic head tester and a magnetic disk tester capable of dynamically positioning a head substantially at a predetermined position on a track or on a track with high speed and accuracy.

The structure of the head assembly driving mechanism or the head holder of the present invention that achieves such an object is that the head holder that holds the head assembly is fixed to the first block, the second block, and the second block . An actuator, the head assembly is fixed to the first block, the first block and the second block are connected by a flexible coupling path at a predetermined interval, and the actuator is driven to The head assembly is swung so that the head moves in the track crossing direction by changing the width of one of the spaces on both sides of the coupling path at a predetermined interval to bend the coupling path.
Further, the coupling path is a single linear elastic member, and the actuator swings the first block with respect to the second block around the coupling path, The head holder is made of one SUS prism material, and the thickness of the first block, the second block, and the coupling path is in the range of 8 mm to 12 mm, respectively, and the coupling path width is 0. In the range of 8 mm to 1.5 mm, the swing drive angle is 1 ° or less.

The magnetic head tester or magnetic disk tester according to the present invention is characterized in that the head assembly driving mechanism or the head holder having the above-described configuration is provided, and the head is turned on with respect to the track to inspect the magnetic head or magnetic disk. Is.
In this invention, the head holder is divided into two blocks via a flexible coupling path, and the first block and the second block are connected by a flexible coupling path at a predetermined interval. Yes. Therefore, if the width of one of the spaces before and after the coupling path is widened, the coupling path is bent and bent, and the remaining other space is narrowed. Conversely, if the width of either the front or rear space is increased, the coupling path is bent in the reverse direction and the remaining one space is narrowed.
The coupling path may be a single elastic member formed in a straight line, and the bending of the coupling path is based on the second block, and the first block supported by the coupling path depends on the amount of deflection. Create a swinging relationship. In other words, the second block is configured to support the first block by the coupling path so as to be able to swing. By adopting such a configuration, the present invention does not need to support the head assembly by a special rotation mechanism that pivotally supports the head assembly, and the head assembly is simply fixed to the first block. The head can be moved in the track crossing direction by swinging.

By the way, when the number of tracks becomes several thousand / inch or more, the rotation angle for dynamically driving the head assembly also decreases, and the head assembly swings less than 1 °, for example, 0.1 ° to 0.3 °. It can be handled with a minute shake of about ゜. The present invention focuses on this point.
Therefore, according to the present invention, the head assembly is swung by bending the joint path by changing the width of the space before or after the joint path by an actuator. At this time, the swing block is only the first block, and the first block is a block that substantially only fixes the head assembly, so that the mass thereof can be reduced. Thereby, reduction of the mass of the swing part corresponding to the rotation part of a prior art can be aimed at.
The actuator can be provided on the second block side, but the mass of the first block can be reduced. However, the actuator may be provided on the first block side when the mass of the actuator is small.
As a result, according to the present invention, since the movable part of the head assembly is a swing mechanism utilizing the elastic deflection of the member, the mass can be reduced and the head assembly can be driven at high speed, and the response speed of the head in the ON track control Can be improved. Therefore, in the magnetic head tester and the magnetic disk tester having the head assembly driving mechanism or the head holder of the present invention, the head is substantially dynamically moved to a predetermined position on the center of the target track or the track with high accuracy. Can be positioned.

FIG. 1 is a plan view of a head holder according to an embodiment to which the head assembly driving mechanism of the present invention is applied, FIG. 2 is a plan view seen from the back side, FIG. 3 is a side view thereof, and FIG. FIG. 5 is a side view of the head carriage in the magnetic head tester or the magnetic disk tester.
1 to 4, 10 is a head assembly driving mechanism, 1 is a head holder, and a head assembly driving mechanism 10 is provided on the head holder 1.
The head holder is a box-shaped block made of SUS (stainless steel) as a whole, and is divided into two blocks via a flexible coupling path 6. The two divided blocks are a prismatic head assembly fixing block (first block) 2 and a prismatic support block (second block) 3 that supports the block.
As shown in FIGS. 2 and 3, the head assembly fixing block 2 has a head clamp mechanism 9 for attaching and detaching the head assembly 4 attached to the lower surface thereof, and supports the head assembly 4 through this. 4a is a head and 4b is a suspension spring.
The support block 3 is a block that is embedded and fixed to the piezo actuator 5 and is attached to the head holder support arm 11 as shown in a partially cutaway sectional view in FIG.

The two blocks of the head assembly fixing block 2 and the support block 3 are substantially equal in thickness and width, and are arranged at a predetermined interval of about 1 mm. A curved connection path (a connecting path (supporting portion of the head assembly fixing block 2)) 6 and a rear end side of the two blocks are connected to support the head assembly fixing block 2 so that the head assembly fixing block 2 can swing (swing). And an auxiliary support portion 7 of the head assembly fixing block 2. The coupling path 6 made of SUS having a width of 1 mm is an elastic body.
In FIG. 2, the coupling path 6 and the connection path 7 are somewhat exaggerated by enlarging the portion of the coupling path 6 in FIG. The head assembly fixing block 2 and the support block 3 are shown spaced apart. The swivel range is indicated by a double arrow on the lower side, and the swivel angle is 0.1 ° before and after, but is exaggerated. The connecting path 7 allows a slight swing (swing) of the connecting path 6 due to its curved state. When the swing angle is about 0.1 °, the head provided on the front end side of the suspension spring can cross the track in an almost linear state.

The coupling path 6 and the connection path 7 are cut out from one block (prism column material) by cutting a groove in the depth direction with a width of about 1 mm substantially at the center thereof. By this cutting, the assembly fixing block 2 and the support block 3 are divided and formed with the coupling path 6 and the connection path 7 interposed therebetween. The thickness (depth) of the coupling path 6 and the connection path 7 is 10 mm. This is the thickness of each of the main body of the head assembly fixing block 2 and the main body of the support block 3 excluding the protruding portion of the head clamp mechanism 9. be equivalent to. Since the support block 3 supports the head assembly fixing block 2, the thickness of the block of the head holder 1 may be about 8 mm to 12 mm, and the width of the coupling path 6 may be selected from about 0.8 mm to 1.5 mm. .
From the relationship of the elastic force of the coupling path 6, if the thickness of the head assembly fixing block 2 is 12 mm or more, the width of the coupling path 6 can be 0.8 mm or less. In this case, the mass of the head assembly fixing block 2 is large. Become. Conversely, if the thickness of the head assembly fixing block 2 is 8 mm or less, the width of the coupling path 6 can be 1.5 mm or more and the mass of the head assembly fixing block 2 can be reduced, but the coupling path 2 is difficult to bend. The force of the piezo actuator 5 has to be increased accordingly, and the response speed control of the head falls.
Of course, the head assembly fixing block 2 and the support block 3 may be coupled by a leaf spring. In this case, the thickness of the coupling path 2 can be 0.8 mm or less, for example, about 0.5 m, and the thickness of the head assembly fixing block 2 can also be 8 mm or less. In this case, the head assembly fixing block 2 and the support block 3 may be coupled by a leaf spring. Each block can be coupled by providing a coupling groove in each block and inserting both ends of the leaf spring into the coupling groove. However, in the case of leaf spring coupling, since the material is different from the material of the head holder 1, there is a problem that a deviation occurs between the head assembly fixing block 2 and the leaf spring due to aging, and accuracy cannot be secured. .

As described above, in FIG. 2, for convenience of description of the coupling path 6, the distance between the blocks and the curved portion are slightly exaggerated, but the length of the head assembly fixing block 2 and the support block 3 is approximately 30 mm. The coupling path 6 is provided at a position about 1/3 of the length from the end on the head side (at a distance of about 10 mm). When the piezo actuator 5 pushes out the screw 21, the width of the space in which the screw 21 is located expands and expands, the coupling path 6 bends counterclockwise, and the width of the space on the head side of the head assembly fixing block 2 becomes narrower. The assembly fixing block 2 swings counterclockwise. Conversely, when the piezo actuator 5 pulls the screw 21, the coupling path 6 is bent in the clockwise direction, the width of the space where the screw 21 is located is narrowed, and the space on the head side of the head assembly fixing block 2 is expanded, thereby fixing the head assembly. Block 2 swings clockwise.
At this time, the coupling path 6 is a SUS having a narrow width of 1 mm when viewed from the plane. 2 is supported in a swinging manner with reference to the coupling path 6. The head swing angle is sufficient if the head assembly swings about 0.1 considering the track width of the magnetic disk. Therefore, as described above, the interval between the spaces on both sides of the coupling path between the head assembly fixing block 2 and the support block 3 is about 1 mm.

As shown in FIG. 2, the piezo actuator 5 is fixed to a storage hole 8 provided on the rear end side of the support block 3 on the opposite side across the coupling path 6 with respect to the front end side to which the head assembly 4 is attached. Yes. The piezo actuator 5 is fixedly inserted into the storage hole 8 and buried and fixed by bonding or the like via the fixing bracket 8a.
The driving surface of the piezo actuator 5 that advances and retreats is integrated with the head assembly fixing block 2 by being screwed with a foot portion of a screw 21 embedded in a corresponding position of the head assembly fixing block 2. The head assembly fixing block 2 and the screw 21 are integrated in the direction in which the piezo actuator 5 advances and retreats by screwing. The head of the screw 21 is provided with a knob 21a, and the fixing bracket 8a is provided with a hole through which the terminal 5a of the piezo actuator 5 passes. The terminal 5a receives a drive signal via the lead wire 5b.
Therefore, when the piezo actuator 5 is driven, the screw 21 advances and retreats accordingly, the flexible coupling path 6 bends clockwise and counterclockwise via the screw 21, and the head assembly fixing block 2 is With the coupling path 6 as the swing center, a minute vibration (swing) is made to swing the head left and right as shown by the arrows on the lower side of FIG. As a result, the head assembly 4 is shaken, and the head 4a on the tip side thereof dynamically moves minutely in a direction crossing a track of a magnetic disk (not shown). At this time, electric power corresponding to the servo signal is supplied to the piezo actuator 5 from the drive circuit (not shown) via the lead wire 5b (see FIGS. 1 and 5) and driven.

By the way, if the knob 21a is turned to slightly extend the foot (tip side) of the screw 21 toward the piezo actuator 5, the coupling path 6 bends slightly forward from the beginning as shown by the dotted line 6a in FIG. The coupling force between the vibration surface and the screw 21 increases, and the repulsive force of the coupling path 6 also increases. Therefore, an appropriate elastic force can be applied to the coupling path 6 by adjustment using the position knob 21a. In this case, the head assembly fixing block 2 swings around the position of the bent 6a.
The connection path 7 serves to support the head assembly fixing block 2 and to restore based on the bending of the coupling path 6. For example, if the coupling path 6 is greatly bent forward from the beginning and the screw 21 and the piezo actuator 5 are always in a strong contact state due to the bending path 6 and the action of the connection path 7, the piezo actuator 5 moves forward and backward. The drive surface and the tip of the screw 21 do not necessarily have to be screwed together.
The connection path 7 may be provided according to the width and depth of the coupling path 6 and the weight of the head assembly fixing block 2 and is not necessarily required for the head swing. Further, by turning the knob 21a of the screw 21, the advance / retreat driving surface of the piezo actuator 5 and the screw 21 are brought into close contact with each other, and these are coupled and fixed. Further, the head position can be adjusted by adjusting the coupling length.

As shown on the side surface of the head holder 10 in FIG. 3, the head assembly fixing block 2 is provided with a head clamp mechanism 9 that detaches the head assembly 4 from the head holder 1. This is mounted and fixed to the lower surface of the head assembly fixing block 2 with screws or the like. Reference numeral 9a denotes an operation lever for fixing / releasing the head assembly.
The head assembly fixing / releasing operation lever 9 a is rotatably fixed inside a rectangular hole 2 a that penetrates the head assembly fixing block 2 and is drilled to the head clamp mechanism 9. The tip end side is supported by the bearing 9b so as to rotate at the bottom of the rectangular hole groove 2a, and the tip protrusion 9c further extending to the lower side of the bearing 9b is engaged with a curved leaf spring (not shown), Push the leaf spring from above to release its biasing force. As a result, the biting suppression block 9d is shifted to the right side of the drawing. Further, by releasing the pushing of the leaf spring, the leaf spring pulls the block 9d with the urging force, and the urging force of the leaf spring is applied to the biting block 9d.

Therefore, when the head assembly fixing / releasing operation lever 9a is in the position of the dotted line, the biting restraint block 9d moves to the right side of the drawing and the head assembly 4 is loosened and the head assembly 4 is released. When the head assembly fixing / releasing operation lever 9a is in the position of the solid line, the bite restraining block 9d is moved to the left side of the drawing by the force of the leaf spring, and the head assembly 4 is fixed to the head clamp mechanism 9.
The new head assembly 4 (magnetic head) is attached by setting the operation lever 9a to the position of the dotted line, turning the head holder 1 upside down and the head clamp mechanism 9 up, and placing the new head assembly 4 (magnetic head) in the head clamp mechanism 9 And the operation lever 9a is returned to the position of the solid line.
Thereby, a head holder in which the magnetic head can be easily replaced is realized. Particularly in a magnetic head tester, this can improve inspection throughput.

As shown in FIGS. 1 and 4, the support block 3 of the head holder 1 is provided with a mounting screw 13 via a screw hole 12 provided on the upper surface of the support block 3 and a head holder mounting hole 11 a of the head holder support arm 11. Thus, the head holder 1 is integrated with the head holder support arm 11. A positioning pin 14 (see FIGS. 1 and 5) is provided on the support block 3 adjacent to the screw hole 12, and when these are integrated, the pin 14 is fitted into the positioning guide hole. .
As a result, the head assembly 4 and the head clamp mechanism 3 are disposed on the front side of the mounting position of the head holder 1 by the mounting screw 13, and the piezo actuator 5 is disposed on the rear side. As a result, the head holder 1 is supported in a balanced state by the head holder support arm 11, and the head positioning accuracy can be improved.

In FIG. 5, 15 is a head carriage (head carriage mechanism), 15a is a moving table, 15b is a guide frame of the moving table, and 16 indicated by a dotted line is an arm mounting base provided on the moving table 15a. . The arm mounting base 16 includes positioning pins 16a and 16d and mounting screws 16b and 16c that are screwed to the moving base 15a below the positioning pins 16a and 16d.
Reference numeral 17 denotes a magnetic disk to be inspected, and reference numeral 18 denotes a spindle.
The head holder support arm 11 has holes 11a to 11c provided corresponding to the positions of the positioning pins 16a and 16d and the mounting screws 16b and 16c, respectively. The head holder support arm 11 is placed on the arm mounting base 16 and corresponds to the corresponding holes 11a and 11c. 11d is mounted and positioned on positioning pins 16a and 16d, and is fixed to the movable table 15a via the arm mounting base 16 by means of mounting screws 16b and 16c via the holes 11b and 11c.

In the above-described embodiment, the head assembly fixing block 2 is provided with the head clamp mechanism 9. However, the head assembly 4 is directly attached to the lower surface of the head assembly fixing block 2 via screws or the like instead of the head clamp mechanism 9. Of course, it may be fixed. In the present invention, it is not always necessary to provide the head clamp mechanism 9 in the head assembly fixing block 2.
Further, the connecting path 7 of the embodiment may be provided according to the relationship between the width and thickness (depth) of the coupling path 6 and the weight of the head assembly fixing block on the swing side as described above. Supportive part. Further, this is only required to allow the head assembly fixing block 2 to swing, and the shape thereof is not limited to the curved one.
Furthermore, in the embodiment, the drive surface of the piezo actuator and the head assembly fixing block are integrated by a screw 21. However, since the flexible coupling path bends and has a return force, it is not always necessary to integrate the driving surface of the piezoelectric actuator and the screw 21.

FIG. 1 is a plan view of a head holder according to an embodiment to which the head assembly driving mechanism of the present invention is applied. FIG. 2 is a plan view seen from the back side. FIG. 3 is a side view thereof. FIG. 4 is a side view of the head holder attached to a support arm such as a carriage. FIG. 5 is a plan-part explanatory view of a head carriage in a magnetic head tester or a magnetic disk tester.

Explanation of symbols

1 ... head holder, 2 ... head assembly fixing block,
3 ... support block, 4 ... head assembly,
4a ... head, 4b ... suspension spring,
5 ... Piezo actuator, 6 ... Connection path,
7 ... Connection path, 8 ... Storage hole, 8a ... Fixing bracket,
9: Head clamp mechanism,
9a: Head assembly fixing / releasing operation lever 10: Head assembly drive mechanism,
11: Head holder support arm.

Claims (15)

In a head assembly driving mechanism for moving the magnetic head in a track crossing direction via a head assembly that supports the magnetic head via a spring,
A head holder for holding the head assembly includes a first block, a second block, and an actuator fixed to the second block ;
The head assembly is fixed to the first block, and the first block and the second block are connected to each other by a flexible coupling path at a predetermined interval.
The magnetic head is moved in the track crossing direction by driving the actuator to change the width of one of the spaces on both sides of the coupling path at the predetermined interval to bend the coupling path. A head assembly ,
The coupling path is an elastic member formed in one straight line, and the actuator swings the first block with respect to the second block around the coupling path,
The head holder is a SUS-made prismatic material, and the thickness of the first block, the second block, and the coupling path is in the range of 8 mm to 12 mm, respectively, and the width of the coupling path Is a head assembly drive mechanism in which the angle of the swing drive is 1 ° or less. Wherein the actuator is a piezoelectric actuator, the head assembly and said piezo actuator the first and second respective head assemblies of the coupling path interposed therebetween mutually claim 1, wherein disposed on the opposite side in block Drive mechanism. 3. The head assembly drive mechanism according to claim 2, wherein the first block and the second block are formed by cutting the coupling path from the one block and dividing the coupling block. 2. The head assembly driving mechanism according to claim 1 , wherein a clamp mechanism for detachably fixing the head assembly is provided in the first block, and an angle of the swing drive is 0.1 [deg.] To 0.3 [deg.]. The first block further includes a screw that is screwed at a position facing a driving surface of the piezo actuator that advances and retreats, and that penetrates the first block, and the piezo actuator includes the second block. The head assembly drive mechanism according to claim 2 , wherein the head end of the screw is coupled to the drive surface. Claim a connection path curved to permit deflection of the first block connecting the said second block and the first block is provided on the opposite side to the head assembly across said coupling path 1 wherein the head assembly drive mechanism. In a head assembly that supports a magnetic head via a spring and a head holder that holds the head assembly,
A first block; a second block; and an actuator fixed to the second block. The head assembly is fixed to the first block. The first block and the second block The block is connected by a flexible coupling path with a predetermined interval, and the actuator is bent by changing the width of one of the spaces on both sides of the coupling path at the predetermined interval. By swinging, the head assembly is shaken so that the magnetic head moves in the cross-track direction ,
The coupling path is an elastic member formed in one straight line, and the actuator swings the first block with respect to the second block around the coupling path,
The head holder is a SUS-made prismatic material, and the thickness of the first block, the second block, and the coupling path is in the range of 8 mm to 12 mm, respectively, and the width of the coupling path Is in the range of 0.8 mm to 1.5 mm, and the head drive angle is 1 ° or less . The head holder according to claim 7, wherein the actuator is a piezo actuator, and the head assembly and the piezo actuator are arranged on opposite sides of the coupling path. The first block and the second block are formed by cutting the coupling path from the one block and dividing it with the coupling path interposed therebetween, and the swing drive angle is 0.1. 9. The head holder according to claim 8 , wherein the head holder is in the range of .degree. The magnetic head is moved in a track crossing direction via a head assembly that supports the magnetic head via a spring, and the magnetic head is controlled to be in a track-on state at a predetermined position on the track or on the track. In a magnetic head tester for inspecting the read / write characteristics of the magnetic head,
A head holder for holding the head assembly;
A head carriage mechanism that supports the head holder via a support arm;
A spindle on which the magnetic disk is mounted,
The head holder has a first block, a second block, and an actuator fixed to the second block ;
The head assembly is fixed to the first block, and the first block and the second block are connected to each other by a flexible coupling path at a predetermined interval.
The magnetic head is moved in the track crossing direction by driving the actuator to change the width of one of the spaces on both sides of the coupling path at the predetermined interval to bend the coupling path. The head assembly is shaken, and the magnetic head is controlled to be in an ON track state on the track ,
The coupling path is an elastic member formed in one straight line, and the actuator swings the first block with respect to the second block around the coupling path,
The head holder is a SUS-made prismatic material, and the thickness of the first block, the second block, and the coupling path is in the range of 8 mm to 12 mm, respectively, and the width of the coupling path Is a range of 0.8 mm to 1.5 mm, and the angle of the swing drive is 1 ° or less . The magnetic head tester according to claim 10 , wherein the actuator is a piezo actuator, and the head assembly and the piezo actuator are arranged on opposite sides of the coupling path. The magnetic head tester according to claim 11 , wherein the actuator is driven in accordance with a servo signal set corresponding to a track on the magnetic disk. The magnetic head is moved in a track crossing direction via a head assembly that supports the magnetic head via a spring, and the magnetic head is controlled to be in a track-on state at a predetermined position on the track or on the track. In a magnetic disk tester for inspecting the read / write characteristics of the magnetic head,
A head holder for holding the head assembly;
A head carriage mechanism that supports the head holder via a support arm;
A spindle on which the magnetic disk is mounted,
The head holder has a first block, a second block, and an actuator fixed to the second block ;
The head assembly is fixed to the first block, and the first block and the second block are connected to each other by a flexible coupling path at a predetermined interval.
The magnetic head is moved in the track crossing direction by driving the actuator to change the width of one of the spaces on both sides of the coupling path at the predetermined interval to bend the coupling path. The head assembly is shaken, and the magnetic head is controlled to be in an ON track state on the track ,
The coupling path is an elastic member formed in one straight line, and the actuator swings the first block with respect to the second block around the coupling path,
The head holder is a SUS-made prismatic material, and the thickness of the first block, the second block, and the coupling path is in the range of 8 mm to 12 mm, respectively, and the width of the coupling path Is in the range of 0.8 mm to 1.5 mm, and the swing drive angle is 1 ° or less . The magnetic disk tester according to claim 13, wherein the actuator is a piezo actuator, and the head assembly and the piezo actuator are arranged on opposite sides of the coupling path. 15. The magnetic disk tester according to claim 14 , wherein the actuator is driven in accordance with a servo signal set corresponding to a track on the magnetic disk.

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