JP2002319254A - Disk evaluation device and control method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic disk evaluation device which enables stable transitions to a servo state. SOLUTION: In the transition to the servo state, impressed current 42 for fixing a rotary positioner 4 has previously been applied by control current of a circuit 43 for servo. During the transition to the servo state, reaction is reduced by gradually decreasing the applied current 42, and further after a lock pin 25 is slightly retreated, the transition to the servos state is performed. Furthermore, the transition to the servos state is completed, by moving a positioner rotating stage 6 to the outermost periphery, after the control system has stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk evaluation apparatus (so-called spin stand) for evaluating a temporary servo signal previously written on a magnetic disk used in a self-servo writing system of a magnetic disk apparatus, and a control method therefor. About.

[0002]

2. Description of the Related Art Hard disk drives (HDDs)
It is widely used as an information storage device, and performs positioning of a head based on a servo signal written on a magnetic disk.

[0003] On a magnetic disk used in an HDD, servo signals and data are recorded / reproduced using a magnetic head. At this time, if a defect exists in the magnetic disk, the recording / reproduction may not be performed sufficiently. Therefore, it is necessary to test whether the magnetic disk satisfies the minimum required performance by itself before incorporating the magnetic disk into the HDD (ie, clamping the magnetic disk to the spindle motor). In general, in this test, a grit characteristic, a certification characteristic, and a contact start / stop (CSS) characteristic of the magnetic disk 1 are sequentially inspected using a test magnetic head.
The number of protrusions on the magnetic disk is checked in the grit characteristic inspection, the electrical characteristics and the presence or absence of defects of the magnetic disk are checked in the certification characteristic inspection, and the durability of the magnetic disk is checked in the CSS characteristic inspection. The device for evaluating the performance of the magnetic disk used at this time is generally called a spin stand.

[0004] Voice coil motors (V
The head positioning type HDD using the rotary positioner using the CM) has an advantage of a compact structure, but has a problem that the head skew angle changes for each track. The head skew angle is related to the flying height of the magnetic head, and appears as a change in the reproduction output from the magnetic head. Therefore, in order to evaluate the performance of the magnetic disk 1, it is necessary to perform the above-described grit characteristic, certify characteristic, and CSS characteristic tests at the same skew angle as that of the HDD. Therefore, when performing these inspections, it is necessary to adjust the positional relationship between the spindle motor of the spin stand and the magnetic head for evaluation to be the same as that of the HDD.
A spin stand provided with a positioning mechanism such as a direct-acting stage or a rotary θ stage has become common.

Conventionally, a servo track writer (STW) has a pin precisely positioned by an external actuator pressed against a rotary positioner in an HDD via a link via a link to determine the position of the pin, and a micro feed mechanism based on a scale inside the actuator. Determine the position. Since the servo signal is written for each track on the magnetic disk, the servo track writer (STW) needs to write the servo signal while accurately positioning all the tracks on the magnetic disk via the links. .

However, in recent years, the number of tracks has increased due to the improvement in recording density, while the track width has decreased. Therefore, it is necessary for a servo track writer (STW) to perform more accurate positioning on more tracks. is there. It requires a high-rigidity and high-cost mechanical positioning mechanism to achieve high-precision positioning, and requires a lot of time for writing. Therefore, prepare multiple servo track writers (STWs) and perform processing in parallel. Is required, the space in the clean room where the servo track writer (STW) is to be arranged is increased, and the cost is increased.

Therefore, in recent years, the above-mentioned servo track writer (STW) has been omitted and a hard disk drive (HD
Attention has been paid to a method of performing self-servo writing by D). In this self-servo writing method,
A temporary servo signal is written on a magnetic disk in advance (for example, if a magnetic pattern is copied from a master to a magnetic disk using a technique such as magnetic transfer, the writing of the servo signal is much more remarkable than a servo track writer (STW)). Can be faster), the magnetic disk to HDD
After that, the actual servo signal is written by the HDD alone based on the temporary servo signal. After that, the magnetic head is positioned based on the servo signal, and it is confirmed that the magnetic head operates normally.

If the servo signal and the temporary servo signal are defective and cannot operate normally, the positioner portion is disassembled again and replaced with a new magnetic disk.
It is necessary to write a temporary servo signal and a servo signal again on the new magnetic disk. Also, since the servo signal is stored alone on the magnetic disk, when the magnetic disk is chucked to the spindle motor of the spin stand, the center position of the track formed by the recorded servo signal and the center of the spindle motor The position may be shifted by several tens to several hundreds μm at the maximum, whereby the reproduced signal from the track is observed as a signal eccentric from the rotation center of the magnetic disk. Therefore, in order to follow the servo signal, it is necessary to form a control system that takes this eccentricity into account.

However, this conventional method aims at shortening the time of the servo track writer (STW) and improving the cost as described above, but it is difficult to evaluate the quality of the servo signal unless an actual servo signal is written. Is troublesome twice and inefficient in terms of cost and time. Therefore, when the servo signal is recorded in advance on the magnetic disk alone, in addition to the evaluation of the magnetic disk alone, the fact that the magnetic head can be positioned by the actual servo signal is described in HD.
Before incorporating into D, it was necessary to make a judgment from a temporary servo signal recorded on a magnetic disk in advance.

Therefore, the present applicant has developed a magnetic disk evaluation apparatus capable of determining the quality of a temporary servo signal without writing an actual servo signal, and has filed Japanese Patent Application No. 2000-219730 filed on Jul. 19, 2000. (Hereinafter referred to as the earlier application).

The prior-art magnetic disk evaluation apparatus is shown in FIG.
This will be described below with reference to FIGS.

FIG. 5 is an overall top view of the magnetic disk evaluation device, and FIG. 6 is an overall front view of the magnetic disk evaluation device. This prior-art magnetic disk evaluation device uses a magnetic head 3
The magnetic head 3 is positioned on the basis of the temporary servo signal read in step (1), and the variation of the magnetic head 3 in the seek direction is measured using the laser Doppler vibrometer 10. That is, a measurement rotation arm 8 that works in conjunction with a rotation stage 6 that holds the rotary positioner 4 is provided, and a laser Doppler vibrometer 10 is installed on the measurement rotation arm 8. The drive of the rotary positioner 4 is controlled based on the provisional servo signal so that the magnetic head 3 is positioned on the concentric circle at the center of the spindle motor 2, and the displacement of the magnetic head 3 in the seek direction is measured. , The settling property (displacement) of the tip of the magnetic head 3 is detected, and the quality of the temporary servo signal is determined from the settling property.

To explain these components in more detail, the magnetic disk evaluation device comprises an evaluation unit 11 having the same configuration as a hard disk drive (HDD) of an actual machine, and a measurement rotating arm 8 located below the evaluation unit 11. And a measurement plate 9 fixed on the measurement rotation arm 8
And a laser Doppler vibrometer 10 mounted on the measuring plate 9.

First, the configuration of the evaluation unit 11 will be described. FIG. 7 is an enlarged top view of only the evaluation unit 11. In the magnetic disk evaluation device of the prior application, the spindle motor 2 for rotating the magnetic disk 32 and the positional relationship between the spindle motor 2 and the evaluation magnetic head are the same as those of the HDD in the same manner as in the known spin stand. A linear motion stage 7 for adjusting the distance is provided on the base 1. On the stage 7, a positioner rotating stage 6 which is a half-moon-shaped plate is mounted, and a lock pin 25 is erected on the positioner rotating stage 6.

Further, on the positioner rotating stage 6, a magnetic disk 3 is provided for evaluating the magnetic disk 32.
2, a magnetic head 3 for reproducing / recording signals on the magnetic head 3, a thin suspension 31 for supporting the magnetic head 3, a thick rotary positioner 4 for supporting the suspension 31, and an end of the rotary positioner 4 opposite to the magnetic head 3. A voice coil 21 provided in the section and a rotary shaft 5 that stands directly on the positioner rotating stage 6 and supports the magnetic head 3, the suspension 31, the rotary positioner 4, and the voice coil 21 are provided.

Further, the voice coil 21 is formed by a magnet 22b directly mounted on the positioner rotary stage 6 and a magnet 22a mounted on the magnet mount jig 23 and mounted on the positioner rotary stage 6 via the magnet mount jig 23. This allows the rotary positioner 4 to be driven with the rotation shaft 5 as the center axis (in the direction of arrow a in FIG. 7) as a voice coil motor (VCM).

Similarly to the rotary positioner 4, the positioner rotary stage 6 is rotatable about the rotary shaft 5 (in the direction of the arrow b in FIG. 7), and stands upright on the positioner rotary stage 6. The lock pin 25 can also rotate to an arbitrary position about the rotation shaft 5. Further, a stopper 24 is provided at the end of the rotary positioner 4 on the voice coil 21 side, and the lock pin 25 and the stopper 24 abut on each other depending on the position of the lock pin 25, and the position of the rotary positioner 4 is regulated.

Similarly, as shown in FIGS. 5 and 6, the measuring rotary arm 8 is rotatable about the rotary shaft 5 (in the direction of the arrow c in FIG. 5). The measurement plate 9 and the laser Doppler vibrometer 10 can be rotated to an arbitrary position about the rotation shaft 5 as a center. The measurement point of the laser Doppler vibrometer 10 is adjusted so as to match the side surface of the magnetic head 3 (that is, the laser irradiation direction of the laser Doppler vibrometer 10 is perpendicular to the side surface of the magnetic head 3). Thus, the amount of change (settling) in the seek direction of the magnetic head 3 can be measured.

Next, an evaluation method of the magnetic disk evaluation apparatus of the prior application having such a configuration will be described.

FIG. 8 is a state diagram of the magnetic disk evaluation apparatus before the start of evaluation. Here, a magnetic disk 32 for evaluation is clamped to the spindle motor 2. Further, a temporary servo signal is written on the magnetic disk 32 in advance.

First, the spindle motor 2 is started to rotate the magnetic disk 32, and the magnetic head 3 of the rotary positioner 4 is loaded on the magnetic disk 32 (the loading process is not shown). At this time, since the power is turned on to the device and a current flows in one direction to the voice coil 21, the rotary positioner 4 rotates in the direction of arrow i in FIG. And is positioned at the initial position.

In this state, by driving the positioner rotating stage 6 to an arbitrary position around the rotating shaft 5, the stopper 24 of the rotary positioner 4 rotates along with the lock pin 25, so that the magnetic head 3 is not controlled. In addition, the magnetic head 3 can be moved to an arbitrary position with mechanical positioning accuracy (positioning accuracy of the positioner rotating stage 6).

In this state, a temporary servo signal written in advance on the magnetic disk 32 by the magnetic head 3 is read, and the amount of eccentricity generated by the magnetic disk chuck or the like is measured and stored in the memory.

Next, as shown in FIG. 9, the positioner rotary stage 6 is further rotated about the rotary shaft 5 in the direction of arrow j in FIG.
Is set to free and the servo state is entered. This servo state means that the positioner rotating stage 6 is rotated at the same time
The current flowing in the voice coil 21 of the rotary positioner 4 in one direction is cut off, and the position of the magnetic head 3 on the magnetic disk 32 is detected based on the provisional servo signal reproduced from the magnetic head 3. That is, positioning control is performed based on the detection signal.

Since this position detection signal includes the amount of eccentricity of the magnetic disk 32, the position detection signal is fed forward with the amount of eccentricity based on the eccentricity data obtained in the memory in the state of FIG. , The eccentricity of the magnetic disk 32 is canceled, and only the resulting head position signal is fed back to perform the positioning control. Thereby, the magnetic head 3 can hold the magnetic head 3 on a concentric circle at the center of the spindle motor 2.

At this time, the displacement of the magnetic head 3 in the seek direction is measured by a measuring device such as the laser Doppler vibrometer 10 described above, and the measured settling property (displacement, variation) of the tip of the magnetic head 3 is evaluated. Accordingly, the signal quality of the temporary servo signal can be numerically confirmed from the settling property, and the quality of the temporary servo signal written in advance on the magnetic disk 32 can be determined. In addition, from the quality judgment of the provisional servo signal, it is possible to evaluate whether or not the magnetic head 3 can be positioned by the actual servo signal before assembling the magnetic disk 32 into the HDD.

When the above-mentioned laser Doppler vibrometer 10 is used in the magnetic disk evaluation apparatus of the prior application, the reflection obtained by irradiating the vibration surface of the object to be measured with a laser beam such as a He-Ne laser beam. Since measurement is performed using light, sufficient focus adjustment is required. However, in the above-mentioned evaluation method of the prior application, since the measurement surface is the side surface of the magnetic head 3, the measurement area is small, so that it is difficult to adjust the focus of the irradiation light. When the evaluation is performed from the inner circumference to the outer circumference of the magnetic disk 32,
Since focus adjustment is required each time, there is a problem in work efficiency. However, these problems can be solved by the following operation shown in FIG.

FIG. 10A shows an example in which the inner peripheral portion of the magnetic disk 32 is measured, and FIG. 10B shows an example in which the outer peripheral portion of the magnetic disk 32 is measured. Is illustrated. First, from the position where the rotary positioner 4 is positioned at the position shown in FIG. 10A, the positioner rotating stage 6 is rotated about the rotating shaft 5 in the direction of the arrow k in the figure to obtain the position shown in FIG. As shown in ()), the rotary positioner 4 moves to the outer peripheral portion.

At this time, the movement angle of the positioner rotation stage 6 is stored in a memory, and then the measurement rotation arm 8 is rotated by the same angle as the movement angle in the same direction (the direction of the arrow 1 in FIG. 10B). By doing so, the laser Doppler vibrometer 10 is also squeezed together, so that once the measurement adjustment is performed in the initial state of FIG. 10A, the focal position is automatically adjusted in FIG. 10B. You will be free from the trouble of making adjustments again.

However, actually, as described above, the positioner rotating stage 6 rotates about the rotating shaft 5 in order to make the rotary positioner 4 free in the servo state.

Thereafter, when the evaluation is completed, a current flows in the voice coil 21 in one direction again, the rotary positioner 4 rotates in one direction, and the positioner rotary stage 6 on which the lock pin 25 is installed rotates, and the rotary positioner 4 rotates. Carry 4 to the unload position. Similarly,
The evaluation magnetic head 3 is unloaded in a procedure reverse to the above-described measurement method. Then, the spindle motor 2 stops rotating, from which the stage 7 moves to the evaluation end position, and a series of servo tests ends.

[0032]

In the above-mentioned magnetic disk evaluation apparatus of the prior application, as shown in FIG. 11, when a current is applied to the voice coil 21 from the bias circuit 44 in the control board 41 by turning on the power. The rotary positioner 4 rotates, whereby the stopper 24 and the lock pin 25 come into contact with each other.
Is rotated, the rotary positioner 4 moves to a predetermined initial position.

Thereafter, in order to shift to the servo state, as shown in FIG. 12, the current by the bias circuit 44 is cut off, and the designated current for control by the servo circuit 43 on the control board 41 is supplied to the voice coil 21. Apply. However, when the current is switched, a current does not flow in a circuit due to switching of a relay or the like, and there is a problem that the rotary positioner 4 becomes free. Therefore, as shown in FIG. 13, during the free state, the rotary positioner 4 moves from the broken line position to the solid line position, causing an offset, and the rotary positioner 4 is out of the controllable range and cannot shift to the servo state. There was something.

At the time of transition to the servo state, if the stopper 24 and the lock pin 25 are in contact with each other as shown in FIG. 14, the reaction force from the lock pin 25 is applied to the rotary positioner 4 via the stopper 24. In some cases, it could not move to the servo state by acting as a disturbance.

Further, when the positioner rotating stage 6 is moved immediately after shifting to the servo state, as shown in FIG. 15, the operation of the positioner rotating stage 6 is performed despite the unstable state of the control system. Since the vibration is applied to the rotary positioner 4 as a disturbance, the servo state cannot be maintained in some cases.

An object of the present invention is to solve the above-mentioned problems and to provide a magnetic disk evaluation device capable of shifting to a stable servo state and a control method thereof.

[0037]

In order to achieve the above object, a magnetic disk evaluation apparatus according to the first aspect of the present invention comprises a base as a support for the apparatus and a magnetic disk to be evaluated rotated at an arbitrary rotation speed. A spindle motor provided on the base for performing the above operation, a magnetic head for recording / reproducing signals to / from the magnetic disk for evaluating the magnetic disk, a thin suspension supporting the magnetic head, and the suspension. A rotary positioner having a large thickness to support, a voice coil provided on an end of the rotary positioner opposite to the magnetic head, and a rotating shaft erected on the base and supporting the magnetic head, the suspension, and the rotary positioner. And a pair of magnets that sandwich the voice coil, and the magnetic head is mounted on the magnetic disk. Fixing means for temporarily fixing the rotary positioner so as to stop at an arbitrary position; supporting the fixing means and the rotary positioner; and fixing the rotary positioner on the magnetic disk in a state where the rotary positioner is fixed by the fixing means. Positioner rotating stage to be moved to a position, and when performing a performance evaluation of a temporary servo signal previously written on the magnetic disk, the temporary servo signal so that the magnetic head is positioned on a concentric circle around the spindle motor. In the magnetic disk evaluation device having a drive control means for controlling the drive of the rotary positioner, a function equivalent to the fixing means is provided by applying a constant current to the rotary positioner by the drive control means. It is characterized by the following.

Here, before shifting to the servo state,
The drive control means for servo may apply a constant current to the rotary positioner.

Further, at the time of transition to the servo state, the current applied to the rotary positioner by the drive control means for servo is gradually reduced, and the positioner rotating stage is finely moved, and thereafter, switching to the servo state is performed. And a control means for retracting the positioner rotating stage to the outermost periphery after the system is stabilized.

According to a fourth aspect of the present invention, there is provided a control method of a magnetic disk evaluation apparatus according to the fourth aspect, wherein the drive control means for the servo is previously supplied with an applied current for fixing the rotary positioner at the time of transition to a servo state. A step of applying a control current of the following, a step of reducing the applied force by gradually reducing the applied current at the time of transition to the servo state, and a step of slightly retracting the lock pin of the fixing means and then returning to the servo state. The method further comprises a step of shifting and, after the control system is stabilized, moving the positioner rotating stage to the outermost periphery to complete the shift to the servo state.

(Operation) In the present invention, with the above configuration, an applied current for fixing the rotary positioner is applied in advance by the control current of the servo circuit at the time of shifting to the servo state, and the applied current is applied at the time of shifting to the servo state. By gradually reducing the reaction force, the reaction force is reduced, the lock pin is slightly retracted, and then the servo state is entered.After the control system is stabilized, the positioner rotary stage is moved to the outermost periphery to enter the servo state Is completed, it is possible to shift to a stable servo state.

[0042]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the configuration of a magnetic disk evaluation apparatus to which the present invention is applied. To facilitate comparison, the same components as those of the above-mentioned prior application shown in FIGS. 5 to 15 are denoted by the same reference numerals.

In the present invention, as shown in FIG. 1, the bias circuit (44 in FIG. 11, etc.) of the prior application is deleted from the control board 41, and only the servo circuit 43 is used. In the device of the prior application, the bias circuit (44) includes the voice coil 21.
By applying a current to the lock pin 2
5 and needed to mechanically position the rotary positioner 4. However, the applied current 42 need only generate a load by which the stopper 24 abuts on the lock pin 25 by the voice coil 21, and therefore the current value does not need to be accurate. Therefore, in the present invention, the servo circuit 43 can be used without using a dedicated bias circuit.
To apply a current approximately equal to that. As a result, the free state of the rotary positioner 4 due to the switching is eliminated, the offset is reduced, and the state is kept within the control range, whereby the servo state can be stably shifted.

Next, as shown in FIGS. 2 and 3, at the time of transition to the servo state (step S11 in FIG. 3), the applied current from the servo circuit 43 is gradually reduced to almost zero (FIG. 3). Step S12). In this state, the lock pin 25 is operated by a minute amount (30 μm) to break the contact with the stopper 24 (step S13 in FIG. 3), and the disturbance due to the reaction force is completely reduced to zero (step S14 in FIG. 3).
Immediately thereafter, a designated current value for control is applied, and the state shifts to a servo state (step S15 in FIG. 3).

In the explanatory view showing the moving position of the rotary positioner 4 in FIG. 4, in the prior application, the applied current is rapidly reduced (83 in FIG. 4, step S in FIG. 3).
2) The rotary positioner 4 is greatly displaced from the target position 82 due to the reaction force from the lock pin 25, and becomes stable in that state. When the designated current is applied to shift from this state to the servo state (85 in FIG. 4, step S3 in FIG. 3), the overshoot 87 is large because the control amount to the target position is large, and it takes time to stabilize. . In the worst case, the shift amount is too large to fall outside the control range, and it is not possible to shift to the servo state.

On the other hand, in the present invention, in order to gradually decrease the applied current (84 in FIG. 4 and step S1 in FIG. 3).
2) The reaction force from the lock pin 25 gradually decreases in proportion to the applied current value. Thereby, the displacement of the rotary positioner 4 from the target position hardly occurs. next,
As shown by the solid line in FIG. 2, by operating the lock pin 25 for 30 μm within the control range (86 in FIG. 4), the disturbance due to the reaction force from the lock pin 25 is reduced to zero. In addition, by suppressing the movement amount of the positioner rotation stage 6 to 30 μm (Step S13 in FIG. 3), the influence of disturbance (vibration or the like) from the positioner rotation stage 6 is reduced.
When the designated current is applied to shift from this state to the servo state (88 in FIG. 4, step S16 in FIG. 3), the state can be reliably shifted to the servo state. In addition, since the control amount is small, a stable state is quickly established (89 in FIG. 4, step S16 in FIG. 3).

Further, in the present invention, after the servo state is stabilized, the positioner rotating stage 6 is retracted to the outermost periphery so that the lock pin 25 does not hinder the servo operation (step S17 in FIG. 3). At this time, disturbance such as vibration due to the movement of the positioner rotary stage 6 is inevitable, but since it is applied after the system is stabilized, the servo state does not become unstable.

(Other Embodiments) An object of the present invention is to provide a recording medium (storage medium) on which a program code of software for realizing the functions of the above-described embodiments is recorded.
Is supplied to a system or an apparatus, and the computer (or CPU or MPU) of the system or the apparatus reads out and executes the program code stored in the recording medium. In this case, the program code itself read from the recording medium implements the functions of the above-described embodiment, and the recording medium on which the program code is recorded constitutes the present invention. As a recording medium for recording the program code and variable data such as a table, for example, a floppy disk (FD), hard disk, optical disk, magneto-optical disk, CD-ROM,
A DR, a magnetic tape, a nonvolatile memory card (IC memory card), a ROM, or the like can be used.

[0050]

As described above, according to the present invention,
When shifting to the servo state, an applied current for fixing the rotary positioner is applied in advance with the control current of the servo circuit, and when shifting to the servo state, the applied current is gradually reduced to reduce the reaction force and lock. Move the pin to the servo state after retracting slightly, and after the control system is stabilized, move the positioner rotary stage to the outermost circumference to complete the transition to the servo state. This makes it possible to perform the transition, and it is possible to stably determine the quality of the temporary servo signal on the magnetic disk.

[Brief description of the drawings]

FIG. 1 is a top view showing the configuration of a magnetic disk evaluation device of the present invention from which a bias circuit has been removed.

FIG. 2 is a top view showing the configuration of the magnetic disk evaluation device of the present invention in which a lock pin 25 is retracted by a small amount.

FIG. 3 is a flowchart showing the operation of the magnetic disk evaluation device of the present invention.

FIG. 4 is an explanatory diagram showing a position of a rotary positioner during a servo operation of the magnetic disk evaluation device of the present invention.

FIG. 5: Applicant's prior application (still unpublished at the time of filing this application)
1 is a top view showing the configuration of the magnetic disk evaluation device of FIG.

FIG. 6 is a front view showing the configuration of the magnetic disk evaluation device of the earlier application.

FIG. 7 is an enlarged top view of an evaluation portion 11 of the earlier application.

FIG. 8 is a top view showing the configuration of a magnetic disk evaluation device before the start of evaluation of the earlier application.

FIG. 9 is a top view showing a configuration of a magnetic disk evaluation device during servo evaluation of the prior application.

FIG. 10A is a top view showing a measurement state of the inner circumference of the magnetic disk of the same prior application, and FIG. 10B is a top view showing a measurement state of the outer circumference of the magnetic disk of the same prior application.

FIG. 11 is a top view showing the configuration of the magnetic disk evaluation device immediately before the shift to the servo operation of the prior application.

FIG. 12 is a top view showing a configuration of a magnetic disk evaluation device during application current switching of the same prior application.

FIG. 13 is a top view showing a configuration of a magnetic disk evaluation device in which an offset 51 of the earlier application has occurred.

14 is a top view showing a configuration of a magnetic disk evaluation device of the prior application receiving a reaction force from a lock pin 25. FIG.

FIG. 15 is a top view showing the configuration of the magnetic disk evaluation device of the earlier application during retreat of the rotary positioner 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Spin motor 3 Magnetic head 4 Rotary positioner 5 Rotation axis 6 Positioner rotation stage 7 Stage 8 Measurement rotation arm 9 Measurement plate 10 Laser Doppler vibrometer 11 Evaluation part 21 Voice coil 22 Magnet 23 Magnet mounting jig 24 Stopper 25 Lock pin 31 Suspension 32 Magnetic Disk 41 Control Board 42 Current 43 Servo Circuit 44 Bias Circuit 51 Offset 61 Reaction Force 71 Vibration

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kimioki Sato 1-1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa F-term within Fuji Electric Co., Ltd. 5D096 AA02 DD05 DD06 GG07 KK02 WW08

Claims (4)

[Claims] A spindle motor provided on the base for rotating a magnetic disk to be evaluated at an arbitrary rotation speed; and a magnetic disk for evaluating the magnetic disk. A magnetic head for recording / reproducing signals to / from a disk; a thin suspension supporting the magnetic head; a thick rotary positioner supporting the suspension; and a rotary positioner provided at an end opposite to the magnetic head on the rotary positioner. A voice coil, a rotating shaft erected on the base to support the magnetic head, the suspension and the rotary positioner, a pair of magnets sandwiching the voice coil, and an arbitrary position on the magnetic disk for the magnetic head. Fixing means for temporarily fixing the rotary positioner so as to stop at A positioner rotating stage that supports the fixing means and the rotary positioner and moves the rotary positioner to an arbitrary position on the magnetic disk while being fixed by the fixing means; Drive control means for controlling the drive of the rotary positioner based on the temporary servo signal so that the magnetic head is positioned on a concentric circle at the center of the spindle motor when performing the performance evaluation of the servo signal. In the magnetic disk evaluation device, the drive control unit applies a constant current to the rotary positioner so as to have a function equivalent to that of the fixing unit. 2. A magnetic disk evaluation apparatus according to claim 1, wherein a constant current is applied to said rotary positioner by said servo drive control means before shifting to a servo state. apparatus. 3. The magnetic disk evaluation device according to claim 1, wherein at the time of transition to a servo state, a current applied to the rotary positioner by the drive control means for servo is gradually reduced, and A magnetic disk evaluation device, comprising: a control means for finely moving a rotary stage, thereafter switching to a servo state, and retracting the positioner rotary stage to the outermost periphery after the system is stabilized. 4. The control method of the magnetic disk evaluation device according to claim 1, wherein an applied current for fixing the rotary positioner at the time of transition to a servo state is previously controlled by a control current of the drive control means for servo. Applying, gradually reducing the applied current at the time of transition to the servo state to reduce the reaction force, slightly retracting the lock pin of the fixing means, and then transitioning to the servo state; Moving the positioner rotary stage to the outermost periphery after the control system is stabilized to complete the transition to the servo state.