JP2581603B2 - Disk recording device - Google Patents

Description

The present invention relates to a disk recording device such as a magnetic disk or an optical disk, and more particularly to arranging a plurality of heads facing a plurality of recording disk surfaces, Integrally supported,
The present invention relates to a head having a head position control device in which one servo head refers to position information to position another head.

[Conventional technology]

Some disk recording devices, such as magnetic and optical devices, have a plurality of recording disks that are integrally rotated by a spindle motor, and a plurality of heads facing the disk surfaces that are integrally moved in the radial direction of the disk surfaces. Some have a mechanism. Then, position information defining the position of each track where data is stored is written to one of the plurality of disk surfaces, and the access mechanism is operated while fetching the position information with a head corresponding to the disk surface. There is a method of positioning each head. The disk surface on which the position information is written is called a servo surface, and the head corresponding to this is called a servo head. The above positioning method is called a servo surface servo method. Also, the disk surface for storing data other than the servo surface is called the data surface,
The corresponding head is called a data head. When the magnetic disk recording device of the servo surface servo system is placed in an environment where the temperature fluctuates, the relative position of the other data head with respect to the servo head changes because the magnitude of thermal deformation of each part of the device is generally not uniform. Would. For this reason, the position of the data head with respect to the track when the data is recorded does not match the position of the data head when the data is read. Such a phenomenon is called thermal off-track. Due to this thermal off-track, the positioning accuracy of the head is limited, and the track density cannot be increased.
This is an obstacle to increasing the storage capacity of the magnetic disk drive.

In order to cancel the influence of the thermal off-track, several methods have been conventionally proposed. Japanese Patent Application Laid-Open No. 62-212982 discloses that a servo track is provided on a data surface of a disk in order to correct thermal off-track, an off-track amount is measured and stored in advance using the servo track, and a data surface is recorded. A method of correcting a positioning signal when accessing a track is proposed. Also, JP-A-63-155478
In the publication, servo information (position information) is recorded in advance on a part of the data surface in order to improve thermal off-track, and the positional deviation amount of each head is measured and stored at a predetermined time. . Then, a position correcting mechanism using a piezo element is provided on the carriage or the magnetic head, and simultaneous positioning of all the heads by the voice coil motor and misalignment correction operation by the piezo element corresponding to the head performing the reading operation are simultaneously performed. Has been proposed.

[Problems to be solved by the invention]

According to the above-mentioned prior art, according to the former publication, from the state of accessing (reading / writing) to one data surface, the same cylinder as the track (at the same position on a plurality of recording disks). Track group)) to access tracks on other data surfaces.
In order to correct the positional deviation of the head, it is necessary to move the voice coil motor and the carriage having a large mass to correct a minute position. However, if a large thrust is applied to perform this operation at high speed, the effect of the natural vibration of the mechanical system becomes remarkable, so that there is a limit to high-speed data head switching.

According to the latter publication, the piezo element operates every time an access operation is performed. At this time, a large voltage change is applied to the piezo element provided near the head, so that the data signal is apt to be affected by noise and data reading / writing is likely to cause an error. In addition, rapid expansion and contraction of the piezoelectric element easily causes vibration of the mechanical system as described above.

SUMMARY OF THE INVENTION An object of the present invention is to provide a disk recording apparatus capable of eliminating the effects of mechanical vibration and noise generated when offset is corrected by a minute displacement element.

It is another object of the present invention to provide a disk recording apparatus that, when a micro displacement element having a hysteresis characteristic is applied, cancels the effect of the hysteresis and enables highly accurate off-track correction. .

[Means for solving the problem]

In order to achieve the above object, the disk recording apparatus of the present invention includes a plurality of recording disks provided in layers at coaxial intervals, and a plurality of heads located opposite to the recording surface of each recording disk. A plurality of head arms respectively supporting the heads as appropriate, an arm support member integrally supporting the bases of the plurality of head arms, and a radial head of the recording disk via the arm support member. A head drive device for moving the head in a direction, and servo position information recorded on one recording surface of the one recording disk is read by a servo head opposed to the recording surface, and the head is read based on the read servo position information. A control device for controlling the position of the other head by controlling a driving device; and a radio device inserted in the middle of each of the head arms according to a voltage applied. A micro-displacement element that is displaced in the disk direction, a reference track provided on at least one recording surface of each of the recording disks, and at least position information in the width direction is recorded, and the control device corresponds to each of the heads. Position control is performed on the reference track, an off-track amount that is a difference between the position information of the reference track read by each head and the servo position information is obtained, and the minute displacement element is set to the off-track amount to zero. And a head position correction device for setting a correction voltage to be applied and applying the correction voltage to the minute displacement element, wherein the head position correction device has a voltage-displacement characteristic of the minute displacement element. A voltage displacement measuring means for measuring, and a correction voltage setting means for setting a correction voltage to be applied to the minute displacement element, Measuring means,
A method in which a voltage applied to the micro-displacement element corresponding to each of the heads is changed, a change in position information of the reference track corresponding to the change is captured, and a voltage-displacement characteristic of the micro-displacement element is measured and stored. The correction voltage setting means obtains a voltage that makes the off-track amount zero based on the stored voltage-displacement characteristics, sets the voltage as the correction voltage, and sets the set correction voltage. The voltage is always applied to the corresponding head.

It is sufficient that the voltage displacement measuring means is operated only when the disk recording apparatus is started, but it is desirable that the voltage displacement measuring means be operated at predetermined intervals.

Further, the head position correcting device is provided with a means for correcting the change over time of the correction voltage, and the means for correcting the change over time obtains the off-track amount at a constant cycle, and stores the off-track amount to zero. It is desirable to make a correction to shift the voltage-displacement characteristic.

It is preferable that the voltage-displacement measuring means measures the voltage-displacement characteristic while temporarily increasing the voltage applied to the micro-displacement element to a predetermined high voltage and then decreasing the voltage.

In addition, when applying the correction voltage to the minute displacement element, it is preferable that the correction voltage setting means lowers the voltage after applying the predetermined high voltage, and then sets the voltage to the correction voltage.

The correction voltage setting means obtains an off-track amount by acquiring position information of the reference head corresponding to the head in a state where the correction voltage is applied, and calculates the correction voltage so that the off-track amount becomes zero. It is desirable to perform the process of correcting again and always apply the re-corrected correction voltage.

Preferably, the correction voltage setting means superimposes an oscillating voltage on the correction voltage.

[Action]

With this configuration, according to the disk recording apparatus of the present invention, the object of the present invention is achieved by the following operations.

First, the voltage of each piezo element is calculated by the voltage displacement measuring means.
Displacement characteristics are measured and stored. Based on this, a correction voltage for setting the offset amount to zero is set by the correction voltage setting means, and the set correction voltage is always applied to the minute displacement element. This allows
The positional relationship between the servo head and each head is always kept constant, and if head access (positioning control) is performed with reference to the servo head, each head is always positioned at the center of the track. In particular, unlike the conventional method in which a correction voltage is applied to the minute displacement element every time access is performed, the problem of mechanical vibration of the access mechanism does not occur. This allows
Access switching of the head can be speeded up. In addition, it is possible to prevent noise from getting on.

In addition, according to the apparatus provided with the aging change correction means, even if the micro displacement element or the access mechanism changes or the thermal characteristics change with time, the off-track correction is performed according to the change, so that the positioning accuracy is improved. Can be maintained.

Further, when the correction voltage is applied, as in the case of measuring the voltage-displacement characteristic, the voltage is once raised to a high voltage and then lowered to set a desired correction voltage.
The head can be positioned with high accuracy by removing the hysteresis characteristic of the minute displacement element.

Further, according to the configuration in which the off-track amount is measured after the application of the correction voltage and the correction voltage is corrected again so as to make the amount zero, the error based on the hysteresis of the minute displacement element is corrected by feedback. As described above, high accuracy can be obtained.

In addition, the hysteresis of the minute displacement element can be removed by applying a vibration voltage to the correction voltage.

〔Example〕

 Hereinafter, the present invention will be described using examples.

FIG. 1 is a block diagram showing a configuration of a head position control device (access servo mechanism) of a magnetic disk drive to which the present invention is applied. In FIG. 1, a control circuit 100 has a function of operating an access servo mechanism in accordance with a command including an address given from a host device. Control circuit 100
Outputs a power amplifier drive signal in response to the command.
This signal is amplified by the power amplifier 101 and applied to the voice coil motor 102. The voice coil motor 102 simultaneously drives all the heads 103 and 104 in the radial direction of the magnetic disk 105 via the carriage. Also, piezo elements 111a, b, c are mounted between the carriage 106 and each of the heads 103,104, and the heads 103,104 are attached to a radius (radial) of the disk 105.
It can be slightly displaced in the direction.
The magnetic disk 105 is concentrically rotated by a spindle motor 107 at a constant speed. A servo surface 120 on which positional information of each track is recorded is formed on one of the plurality of disk surfaces of the magnetic disk 105, and the other surface is a data surface 130 for storing data information. The signal read by the servo head 104 corresponding to the servo surface 120 is amplified by the amplifier 121 and read into the control circuit 100 as the position signal 122. On the other hand, each signal read by each head 103 corresponding to the data surface 130 is read amplifier 131
, And one of them is selected by the multiplexer 132. The selected signal is input to the control circuit 100 as a data signal, and is input to the microcomputer 150 via the AD converter 151.

The microcomputer 150 includes the piezo element 1 described above.
11a, b, c has a function to drive, the driving signal, D / A converter 152a, b, c, via the amplifier 155a, b, c, piezo element
Input to 111a, b, c. The microcomputer 150
Sends and receives an interface signal with the control circuit 100, and manages execution of the thermal off-track correction operation. The multiplexer 132 receives a head selection signal from one of the control circuit 100 and the microcomputer 150, and outputs head data corresponding to the selection signal to the A / D converter 151.

FIG. 2 is a schematic sketch showing the detailed structure around the head and the disk. In FIG. 2, the spindle motor 10
One of the disk surfaces which are integrally rotated by 7 is a servo surface 120, and a servo signal (position information) defining the position of each track is recorded on the servo surface 120. This servo signal is read by the servo head 104. Each of the remaining disc surfaces has a data surface 13 for recording data information.
It is 0. One or more reference cylinders 136 are formed on these data surfaces 130. At least a servo signal indicating position information in the width direction is written in each reference track 136, and a data head 103 corresponding to each data surface is written.
Then, the servo signal is read. On the other hand, these heads 103 and 104 are attached to a head arm 163 via a support spring 162. The piezo elements 111a, 111b and 111c are incorporated in the head arm 163, and are controlled by the microcomputer 150. The head arm 163 is fixed to the carriage 106, and the carriage 106 is driven by the voice coil motor 102 in the radial direction of the disk.

Hereinafter, the configuration of off-track correction, which is a characteristic part of the present invention, will be described together with the operation. In FIG.
5 shows a flowchart of a processing procedure of an embodiment of off-track correction. This series of processing is performed by the microcomputer
This is executed by a timer interrupt by 150.

First, it is determined whether an off-track correction operation can be performed by checking an interface signal provided from the control circuit 100 (step 301). If it is not executable, it waits until it becomes executable. If it is executable, it sends a signal to the control circuit 100 indicating that the correction operation is being performed, and proceeds to the next step (step 302). In the next step 303, the address of the cylinder that the head is currently following is stored in preparation for returning from the off-track correction operation. Next, after moving the head to the reference cylinder, the off-track correction operation shown in the flowchart of FIG. 4 is executed (step 305). When the off-track correction operation is completed, the head is returned to the cylinder position before the correction operation stored in step 303 (step 306). Then, in step 307, the signal indicating that the correction operation is being performed is released, the off-track correction operation is completed, and the state returns to the state before the interruption.

Here, the processing of the off-track correction operation portion in step 305 will be described with reference to the flowchart shown in FIG. In this embodiment, two heads are mounted on one head arm 163. If both of these heads are data heads, the following processing is executed using one of them as a representative head. When one of the heads is the servo head 104, a predetermined input is applied to the piezo element of the head arm 163, and the processing described below is not executed. First, the first head as a correction operation target is selected from a plurality of ordered representative heads,
A signal for selecting this head signal is output to the multiplexer 132 (step 401). Next, immediately after the apparatus is started, it is determined whether the previous correction data is not stored, that is, whether or not it is an initial operation (step 402). In the case of the initial operation, the loop counter is set to “0” (step 403), and the voltage-displacement characteristic is measured while driving the piezo element 111 attached to the head arm on which the selected representative head is mounted. Is created (step 404). The measurement of this voltage-displacement characteristic
As shown in FIG. 5, first, a sufficiently large constant voltage (100 V in the illustrated example) is applied to the piezo element.
The voltage is reduced at a constant voltage step width (5 V width in the illustrated example), and the displacement of the head with respect to the voltage is measured. This process is repeated until the voltage becomes zero. The measured displacement at each voltage represents the amount of off-track based on the center of the reference track, and this is stored in the memory of the microcomputer 150 in the form of a table. Note that the displacement amount is obtained based on the servo signal of the reference track.

Next, referring to the obtained voltage-displacement characteristic table, a voltage is calculated for setting the head off-track amount to "0" (step 405). First, the data (off-track amount of the head) stored in the table is converted to the voltage 0
Are referred to in order from the value corresponding to, and a place where the sign is inverted is found. FIG. 6 is an enlarged graph of this portion. From this figure, the voltage Vpo for setting the off-track amount to “0” can be calculated by the following interpolation formula.

Of course, when the off-track amount stored in the table is “0” itself, the voltage corresponding to this is set to Vpo. If the voltage for setting the off-track amount to “0” cannot be determined due to an operation failure of the device, the following processing can be interrupted and the processing can branch to an error processing routine.

When Vpo is determined, Vpo is applied to the piezo element 111 (step 406). Here, FIG. 7 shows a graph of the voltage applied to the piezo element 111 and the corresponding hysteresis curve of the displacement. In this history, in the case of the initial operation, the voltage applied to the piezo element is OV since the voltage-displacement amount table has just been created (point A in the figure). When the above-described correction operation is already performed instead of the initial operation, the applied voltage is not necessarily OV (point B). In any case, after the applied voltage is once increased to 100 V, the applied voltage is applied so as to decrease toward the correction voltage Vpo at which the already determined off-track amount becomes “0”. Thereby, an error due to the hysteresis characteristic can be eliminated. Next, the set correction voltage Vp
For o, the off-track amount is measured for confirmation (step 407). In this measurement, the servo signal of the reference track read by the head 103 is repeatedly input to the microcomputer 150 through the AD converter 15 while rotating the disk, and the average off-track amount for one rotation of the disk is calculated. It is done by doing. If the measured off-track amount is equal to or less than a predetermined allowable value,
The selection of the current representative head is canceled (step 409), the head address is updated to switch to the next representative head (step 410), and the process returns to head selection via step 411. In step 411, it is determined whether the learning processing of the voltage-displacement characteristics corresponding to all the representative heads has been completed, and if it has been completed, the off-track correction processing is completed.

If it is determined in step 408 that the measured off-track amount exceeds the predetermined allowable value, “1” is added to the loop counter (step 412), and if the result is less than “2”, Returning to step 404, the generation of the voltage-displacement characteristic table is executed again (step 413). On the other hand, if the result of adding “1” to the loop counter is “2” or more, it is regarded as abnormal, and the flow branches to an error processing routine (step 414).

As described above, the voltage-displacement characteristics of each piezo element 111 are measured to determine the amount of off-track, and further, a correction voltage Vpo for canceling the amount of off-track is determined, and this is applied to the piezo element 111 for verification. If the off-track amount is equal to or less than the allowable value, the correction voltage Vpo is constantly applied to the corresponding piezo element 111, and the servo head 104 and each head 103
Is corrected to a fixed relationship (matched relationship).

As described above, according to the present embodiment, the servo head 10
Since the positional relationship between 4 and each head 103 is always kept constant, the access mechanism (head positioning mechanism) is compared to the conventional method that corrects the thermal off-track at each access.
This eliminates the problem of vibration. This makes it possible to speed up head switching.

In addition, since the offset amount is not corrected at the time of access due to reading and writing, the voltage applied to the piezo element 111 does not fluctuate, and noise can be prevented from reading and writing data, thereby preventing an error from occurring. Can be.

In addition, when measuring the voltage-displacement characteristic of the piezo element 111 and applying the correction voltage Vpo obtained based on this, once a high voltage, desirably a saturation curve viewed from the hysteresis curve of the voltage-displacement characteristic of the piezo element 111 is obtained. Since the operation is performed so that the voltage is increased to the voltage and then reduced to the desired voltage, the influence of the hysteresis characteristic of the piezo element 111 can be eliminated.

Next, after the above-described thermal off-track correction is performed, a description will be given of a response to a change in the thermal off-track amount or a change in the voltage-displacement characteristic of the piezo element 111 due to aging or a change in environmental conditions. I do. in this case,
The determination in step 401 in FIG. 4 is “NO” and step 421
Processing branches to processing of 424. In step 421, the off-track amount of the head 103 is measured in the same procedure as in step 407 described above. Then, it is determined whether the off-track amount is equal to or less than the allowable value (step 422). If the amount is equal to or less than the allowable value, the correction voltage Vpo of the head 103 is determined to be appropriate and the next head
Switch to 103 and repeat the same process (steps 409-41
1). If the value exceeds the allowable value, set the loop counter to 0.
(Step 423), the voltage-displacement characteristic table already existing in the memory is shifted by the off-track amount (step 424). FIG. 8 shows the voltage-
It is the figure which showed the table of the displacement characteristic as a graph. In the shift processing described above, the voltage-displacement characteristic A which has been set conventionally in FIG. 8 is used, and when a negative value Δ is measured as the off-track amount, the voltage-displacement characteristic A This is performed by adding Δ to each numerical value to obtain a new voltage-displacement characteristic B. After this processing, the process proceeds to step 405, in which a correction voltage Vpo for canceling off-track is obtained and its set value is changed as in the case of the initial operation (step 406). Subsequent steps are the same as in the initial operation.

As described above, in the present embodiment, the head is
Measure the off-track amount of 103, and if this is different from the initial or previously set amount, the correction voltage
Since the Vpo is corrected and set, off-track correction can be performed in accordance with the aging of the piezo element 111 and the entire access mechanism, and highly accurate positioning can always be performed. In addition, since the voltage-displacement characteristics of the piezo element 111 are shifted again by the amount corresponding to the deviation of the off-track amount except for the initial operation, the correction process can be performed in a short time. Less impact on time.

In the above embodiment, in order to eliminate the influence of the hysteresis characteristic of the piezo element 111, a method of temporarily increasing the voltage to a saturation voltage and then decreasing the voltage to a predetermined correction voltage Vpo is adopted. The effect of the above-mentioned hysteresis can also be eliminated by such a method. FIG. 9 shows a flowchart of the first method. In this embodiment, a feedback loop of a servo system is provided to remove hysteresis. First, the servo head 104 and the voice coil motor 102
Thereby, the target head 103 is positioned on the reference cylinder. Then, similarly to the above embodiment, the piezo element 111
The correction voltage Vpo is obtained based on the voltage-displacement characteristic of the above, and the correction voltage Vpo is applied to the piezo element 111 and temporarily corrected. In this state, the microcomputer 150 takes in the position information from the head 103 via the multiplexer 132 and the A / D converter 151 (step 501). The off-track amount is obtained from this position information, and the correction voltage Vpo is corrected by proportional (P) or proportional integral (PI) processing so as to make it "0" (step 502). This corrected correction voltage Vpo is applied to the piezo element 111 via the D / A converter 152 (step 50).
3). As a result, a servo feedback loop including the head 103 and the piezo element 111 is formed, and the head 10
3 is positioned at the center of the reference track. The ninth
The process shown in the figure is repeated several times, and when a certain period of time has elapsed, that is, when the servo loop system has converged, the output of the D / A converter 152 at that time is held. Thus, the influence of hysteresis can be eliminated without once applying the saturation voltage of the piezo element 111.

The second method uses a piezo element 111 as shown in FIG.
The oscillating signal voltage (dither signal) from the dither signal generator 160 is superimposed on the correction voltage Vpo applied to. Thus, the effect of the hysteresis of the piezo element 111 can be eliminated.

〔The invention's effect〕

As described above, according to the present invention, when correcting the off-track of each head, the correction operation is completed by a specific reference cylinder, so that it is necessary to displace the minute displacement element during the access operation. There is no. As a result, there is no time required for the generation and response of vibrations associated with the displacement correction operation, and the off-track correction can be performed without increasing the access time.

Further, since there is no input change of the micro displacement element at the time of data reading / writing, noise due to the input change does not ride on the data to be read / written, and the reliability does not decrease.

Further, even when the minute displacement element has a hysteresis characteristic, off-track correction can be performed without being affected by the hysteresis characteristic, and the accuracy is improved.

Further, even when it is detected that the off-track amount exceeds the allowable value during operation, it is not necessary to re-measure the input-displacement amount characteristic table again, so that the off-track correction process can be performed in a short time. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a head position control device which is a main part of a disk recording apparatus according to an embodiment of the present invention. FIG. 2 is a schematic view schematically showing a structure around a head and a disk. FIG. 4 is a flowchart showing the flow of the entire off-track correction operation, FIG. 4 is a flowchart showing the length of the main process of the off-track correction operation, FIG. 5 is a graph showing a method of measuring the voltage-displacement characteristic, and FIG. Figure 6 is the fifth
FIG. 7 is an enlarged graph showing a portion where the sign is inverted, FIG. 7 is a graph of a hysteresis curve showing a relationship between applied voltage and displacement of the piezo element, FIG. 8 is a graph showing shift processing of voltage-displacement characteristics, FIG. 9 is a flowchart of another embodiment for removing the hysteresis of the piezo element, and FIG. 10 is a block diagram of a main part of still another embodiment for removing the hysteresis of the piezo element. DESCRIPTION OF SYMBOLS 100: control circuit, 102: voice coil data, 103: head, 104: servo head, 106: carriage, 105: magnetic disk, 111a to c: piezo element, 120: servo surface, 130
… Data plane, 132… multiplexer, 136… reference track, 150… microcomputer, 151… A / D converter, 152
(Ac) ... D / A converter, 163 ... head arm.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yuji Nishimura 2880 Kozu, Kozuhara, Odawara City, Kanagawa Prefecture (72) Inventor Takeshi Takahashi 2880 Kozuhara, Kozuhara, Odawara City, Kanagawa Prefecture Inside Odawara Plant, Hitachi, Ltd. 72) Inventor Shigeyoshi Saito 2880 Kozu, Odawara-shi, Kanagawa Prefecture Hitachi Odawara Plant Co., Ltd.

Claims (7)

(57) [Claims] 1. A plurality of recording disks provided in layers in a coaxially spaced manner, a plurality of heads positioned opposite to a recording surface of each of the recording disks, and a plurality of heads respectively supported as appropriate. A plurality of head arms, an arm support member for integrally supporting the bases of the plurality of head arms, a head drive device for moving the head in the radial direction of the recording disk via the arm support member, Servo position information recorded on one recording surface of one recording disk is read by a servo head facing the recording surface, and the head driving device is controlled based on the read servo position information to control the other heads. A micro displacement element inserted in the middle of each of the head arms and displaced in the radial direction according to the applied voltage; Each recording surface of each recording disk has at least one
A reference track on which at least position information in the width direction is recorded; and the control device controls the position of each head to the corresponding reference track, and the position information of the reference track read by each head and the servo. An off-track amount that is a difference from position information is obtained, a correction voltage to be applied to the minute displacement element is set so that the off-track amount becomes zero, and a head position correction that applies the compensation voltage to the minute displacement element A disk recording device comprising: a voltage displacement measuring means for measuring a voltage-displacement characteristic of the minute displacement element in the head position correcting device; and a compensation voltage for setting a compensation voltage to be applied to the minute displacement element. Setting means, wherein the voltage displacement measuring means changes a voltage applied to the minute displacement element corresponding to each of the heads, A change in the position information of the reference track with respect to the micro-displacement element is taken in, and the voltage-displacement characteristic of the minute displacement element is measured and stored. A disk recording method for obtaining a voltage for setting the off-track amount to zero based on the voltage, setting the voltage as the correction voltage, and constantly applying the set correction voltage to the corresponding head. apparatus. 2. A disk recording apparatus according to claim 1, wherein said voltage displacement measuring means is operated only when said disk recording apparatus is started. 3. The head position correcting apparatus further comprises means for correcting the correction voltage with time, wherein the time-dependent change correction means obtains the off-track amount at a constant period and sets the off-track amount to zero. 3. The disk recording apparatus according to claim 2, wherein a correction for shifting the stored voltage-displacement characteristic is performed. 4. The method according to claim 1, wherein the voltage-displacement measuring means measures the voltage-displacement characteristic while increasing a voltage applied to the small displacement element once to a predetermined high voltage and then decreasing the voltage. 4. The disk recording device according to claim 1, 2, or 3, wherein 5. The correction voltage setting means, when applying the correction voltage to the minute displacement element, applies the predetermined high voltage and then lowers the voltage to set the correction voltage. The disk recording device according to claim 4, wherein 6. The correction voltage setting means obtains an off-track amount by acquiring position information of the reference head corresponding to the head in a state where the correction voltage is applied, and sets the off-track amount to zero. 5. The disk recording apparatus according to claim 4, wherein a process of correcting the correction voltage again is performed, and the re-corrected correction voltage is always applied. 7. The disk recording apparatus according to claim 4, wherein said correction voltage setting means superimposes an oscillating voltage on said correction voltage.