JPH0793926A - Magnetic disc apparatus - Google Patents

Abstract

PURPOSE:To obtain a disc apparatus capable of positioning a head at high velocity with high accuracy without reducing the area at all where data can be stored. CONSTITUTION:A plurality of conductive bodies 13 and a recording/reproducing head member 14 for recording/reproducing data are integrally coupled into a magnetic head 11. Before data are recorded/reproduced, the conductive bodies 13 and recording/reproducing head member 14 are brought in touch with a magnetic disc 12. On a protective film 17 of the magnetic disc which is a contact face with the magnetic head 11, first areas 18 made of a material of a relatively high dielectric constant and second areas 19 made of a material of a relatively low dielectric constant are alternately formed at specific intervals. The capacitance between the conductive body 13 and magnetic disc 12 which changes as the magnetic head 11 moves is detected for each conductive body 13 of the magnetic head 11, so that the magnetic head is positioned with the use of the detected signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device for positioning a magnetic head on a target data track according to position information provided on the magnetic disk.

[0002]

2. Description of the Related Art A magnetic disk of a magnetic disk device is
In order to perform control for determining the position of the magnetic head, a servo sector in which information for positioning the magnetic head is recorded is provided in addition to the data area.

Conventionally, as a magnetic disk device having servo information, a magnetic disk device of a servo surface servo system having a data sector dedicated surface for storing data and a servo information dedicated surface, and a sector servo which is one of the data surface servo systems are used. System magnetic disk drives have been used. But,
In recent years, the sector servo system has been used more frequently than the servo surface servo system in magnetic disk devices. The sector servo system is a sample value system control system that controls the positioning of the head by using servo information intermittently obtained from the servo sector at a constant cycle as the magnetic disk rotates. According to the magnetic disk device of No. 3, the magnetic disk used in this device is provided with data sectors, which are data recording / reproducing areas, and servo sectors, which are considerably finer than the data sectors, in servo information areas alternately in the circumferential direction.

In the above-mentioned servo surface servo system, thermal off-track (deviation between magnetic head and track due to deformation due to heat) becomes a problem, but in a sector servo system magnetic disk, servo information is provided on the data surface of the magnetic disk. Therefore, such a problem of thermal off-track does not occur. Further, the smaller the number of disks per device, the better the format efficiency than the servo surface servo system that requires one dedicated servo surface, and the sector servo system is suitable for downsizing of the disk device. Due to these advantages, the sector servo system has been widely used.

[0005]

However, since the sector servo type magnetic disk is of the sample value control type, the area occupied by the servo sector is limited with respect to the recording area of the magnetic disk. In fact, the upper limit of the size of the servo sector area is 1/10 to 10 of the sampling frequency.
It is 1/7. Therefore, the magnetic disk device of the sector servo system has a problem that the servo band of the magnetic head control system is limited, a sufficient gain cannot be obtained in a low range, and it is vulnerable to disturbance such as vibration and shock applied to the device. Since the servo band becomes low, it is difficult to realize fast seek performance, the settling characteristic is bad, the track access time becomes long, and there is a problem that the high frequency off-track component cannot be followed.

Further, in order to improve the control performance, it is sufficient to increase the number of servo sectors in order to obtain more servo information in one rotation of the disk, but in this case, the problem that the data storage area decreases and the data storage Since the servo information is formed in a part of the feasible area, the data storage capacity is 10 to 2
There is also the problem of a 0% reduction.

Therefore, an object of the present invention is to obtain a signal for head positioning continuously or almost continuously from the data surface without reducing the data storable area at all, and control without reducing the data area. It is an object of the present invention to provide a disk device capable of increasing the sampling frequency of the system, obtaining a sufficiently wide servo band, and capable of head positioning with high speed and high accuracy.

[0008]

According to the present invention, a plurality of conductors and a recording / reproducing head member for recording / reproducing data are integrally coupled to form a magnetic head, and the conductors and the recording / reproducing are performed during data recording / reproducing. The head member contacts the magnetic disk, and the protective film of the magnetic disk, which is the contact surface with the magnetic head, has a first region made of a relatively high dielectric constant material and a first region made of a relatively low dielectric constant material. Two regions are formed alternately at a specific interval, and the capacitance between the conductor and the magnetic disk that changes as the magnetic head moves is detected for each conductor of the magnetic head,
There is provided a magnetic disk device that positions a magnetic head by using these detected signals.

Further, according to the present invention, a rotary drive mechanism for rotationally driving a magnetic disk in which position information for positioning the magnetic head is recorded in advance, and the magnetic head is moved in the radial direction of the magnetic disk based on a positioning control signal. The moving mechanism, the reading means for reading the position information recorded on the magnetic disk, the resonance characteristic with respect to the frequency component of the vibration disturbance applied to the voice coil motor (VCM), and the shake of the entire rotating portion of the rotary drive mechanism. A magnetic disk drive having a controller for generating a control signal for controlling a moving mechanism having anti-resonance characteristics is provided.

Further, according to the present invention, a rotary drive mechanism for rotationally driving a magnetic disk on which position information for positioning the magnetic head is recorded in advance, and the magnetic head is moved in the radial direction of the magnetic disk based on a positioning control signal. In a magnetic disk device having a moving mechanism for moving the magnetic disk, a reading means for reading the position information recorded on the magnetic disk and an integral multiple of the vibration frequency of the magnetic disk housing generated by the rotational driving force of the rotary driving mechanism. There is provided a magnetic disk device comprising a first controller having a resonance characteristic in frequency and a second controller having an anti-resonance characteristic in the frequency of the vibration of the entire rotating portion of the rotation drive mechanism.

There is provided a magnetic disk device, wherein the first controller has a resonance characteristic in which each Q value is 2.0 or more.

A magnetic disk drive characterized in that the second controller has an anti-resonance characteristic in which each Q value is 1.5 or less.

[0013]

According to the present invention, a change in electrostatic capacitance between a plurality of conductors provided on the magnetic head and the magnetic disk is detected for each conductor, and the electrostatic capacitance between the conductor and the magnetic disk is detected. Since the change in capacity is used as a signal for positioning the magnetic head, it is not necessary to secure a servo information area for head positioning in the data storable area on the magnetic disk. From the aspect, since it can be obtained continuously and continuously, the control band of the magnetic head positioning control system can be sufficiently widened without lowering the format efficiency, and high precision positioning and high speed seek can be realized.

According to the present invention, the controller for generating the control signal for controlling the moving mechanism based on the position information is provided with a VC.
By attaching a controller having resonance characteristics to the frequency component of the torque disturbance applied to M and a controller having anti-resonance characteristics to the shake of the entire rotating portion of the rotary drive mechanism, a track following control system is provided. The positioning accuracy of can be improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows a magnetic head 11 and a magnetic disk 12 according to an embodiment of the present invention. The magnetic head 11 is composed of a plurality of conductors 13 each composed of at least one conductor and a data recording / reproducing head member 14. The magnetic disk 12 has a glass substrate 15
And the magnetic layer 16 formed on the upper surface of the glass substrate 15.
And a protective film 17 formed on the magnetic layer 16.

At least the conductor 13 and the data recording / reproducing head member 14 of the magnetic head 11 are in contact with the protective film 17 of the magnetic disk 12 even while the disk 12 is rotating. The protective film 17 of the magnetic disk 12 is formed of a first region 18 made of a material having a relatively high dielectric constant and a second region 19 made of a material having a relatively low dielectric constant.

The arrangement of the first region 18 and the second region 19 of the protective film 17 on the magnetic disk 12 is shown in FIGS. 2 and 3. That is, on the magnetic disk 12 protective film 17 which is the contact surface with the magnetic head 11, the first regions 18 and the second regions 19 are contiguous to each other in the radial direction alternately in a concentric or spiral shape as shown in FIG. Has been formed. FIG. 3 is an enlarged view of the cross section A-B of the magnetic disk of FIG. 2, in which the protective film 17 of the magnetic disk 12, which is the contact surface with the magnetic head 11, has a second region 19 having a width Ra. Are formed at intervals T, and the first region 18 is formed between and over the second regions 19.

Various structures of the magnetic disk will be described with reference to FIG.

In FIG. 4, the magnetic disk 22 includes a substrate 23 made of a non-conductive material such as glass and a metal (thin).
It is composed of a magnetic layer 24 made of a film and a non-conductive protective film 25.

In the example of FIG. 4A, the protective film 25 is the first
Region 26 and a second region 26 which is arranged below the first region 26 at regular intervals in the radial direction and is in contact with the magnetic layer 24. The first region 26 is formed of a material having a predetermined dielectric constant, and the second region 27 is formed of a material having a dielectric constant lower than that of the material forming the first region.

In the example of FIG. 4B, the second regions 27 of the protective film 25 are formed at regular intervals in the radial direction so as to be embedded in the middle of the first regions 26, and the second regions 27 are formed. It is formed of a material having a dielectric constant lower than that of the first region 26.

In the example of FIG. 4C, the second regions 27 of the protective film 25 are provided in the upper part of the first region at regular intervals in the radial direction and have a dielectric constant lower than that of the first region 26. It is formed by the material.

In the example of FIG. 4D, the second region 27 of the protective film 25 is formed of a material having a dielectric constant lower than that of the first region, and reaches the surface from the bottom surface of the first region 26. ing.

Next, a method of positioning the head using the magnetic head 11 and the magnetic disk 12 will be described with reference to FIG.

As shown in FIG. 5A, the magnetic head 11 is provided with _two conductors 13 ₁ and 13 ₂ whose contact area with the magnetic disk 22 is S. Further, as shown in FIG. 1, the magnetic disk 12 includes a glass substrate 15, a magnetic layer 16 of a metal thin film, a first region 18 of a protective film 17 made of a non-conductive material, and a dielectric constant lower than that of the first region. And a second region 19 of material. further,
A constant potential is maintained between the magnetic layer 16 which is a metal thin film under the protective film 17 of the magnetic disk 12 and the conductors 13 ₁ and 13 _2, and currents are connected in series to the conductors 13 ₁ and 13 _2. The detectors 31 and 32 are connected.

In this embodiment, the magnetic layer 16 and the conductor 13 ₁
The change in capacitance between 1 and 13 ₂ is detected by the current detectors 31 and 32 as a change in current. It should be noted that a resonance circuit is formed externally, a frequency adapted to the resonance characteristic is given to this resonance circuit from the external oscillator, and the resonance characteristic is changed by the change in the electrostatic capacitance between the conductors 13 ₁ and 13 ₂ and the magnetic film 16. Changes may be detected.

When the magnetic head 11 moves in the disk radial direction, the area occupied by the first region 18 and the second region 19 between the conductors 13 ₁ and 13 ₂ and the magnetic layer 16 changes, so that the area changes. Is considered to be the change in capacitance. That is, when the magnetic head 11 moves in the disk radial direction, the first region 18 between the conductor 13 ₁ and the magnetic layer 16 is
The area occupied by is changed as shown in FIG. Further, when the magnetic head 11 moves in the disk radial direction, the second region 19 between the conductor 13 ₂ and the magnetic layer 16 is formed.
The area occupied by is changed as shown in FIG. In this way, as the magnetic head 11 moves in the disk radial direction, the current detectors 3 of the conductors 13 ₁ and 13 ₂ are moved.
Current changes detected from 1 and 32 are represented by Ia and Ib.
The magnetic head 11 is positioned as follows using this change in current.

That is, the conductor 13 as shown in FIG.
Detected current Ia from ₁ and detected current I from conductor 132
The difference signal Id = Ia−Ib from b is obtained. Current Id
When is positive, a force in the inner circumferential direction proportional to the value is applied to the magnetic head, and when the current Id is negative, a force in the outer circumferential direction proportional to the absolute value of the value is applied to the magnetic head 11. .
By controlling in this way, the magnetic head moves to each position X _n (here, X _{n + 1) of the} interval T where the difference current Id = 0.
= X _n + T).

The magnetic head 11 is used for the magnetic disk 12 in which the interval between the second regions 19 is T and the width is Ra.
The number N of the conductors 13 integrated with and the width Tw of the contact portion with the disk 12 correspond to the polarity change point (positioning point X _n) of the difference signal Id obtained as the magnetic head 11 moves in the disk radial direction. It is desirable to select so that a difference signal having a wide linearity and good linearity can be obtained before and after that.

As described above, according to the present invention, since the magnetic head 11 is positioned at every interval T of the second area 19 of the magnetic disk, the data track recorded and reproduced by the magnetic head 11 on the magnetic layer 16 of the magnetic disk 12. The pitch can be n × T (n: positive integer).

Further, at the time of seek, it is possible to obtain the distance traveled by the magnetic head 11 by detecting the number of periodical changes in the dielectric constant of the above T, and to perform seek control of the head 11. The peak or valley of the change in permittivity is k
If it is detected once, the moving distance of the magnetic head 11 is k × T.
Obtained as.

In the above embodiment, the region having a dielectric constant smaller than that of the protective film is formed inside or on the surface of the protective film, but the region having a dielectric constant larger than that of the protective film is formed. May be. Furthermore, if the magnetic layer is a non-conductive material, a material having a different dielectric constant may be provided in the lower magnetic layer below the magnetic layer. Alternatively, a dedicated film provided with materials having different dielectric constants may be formed inside the magnetic disk or on the surface of the magnetic disk. Further, in the above-mentioned embodiment, the materials having different permittivities are arranged concentrically on the magnetic disk so as to be continuously changed. However, the materials having the permittivity are arranged in the circumferential direction like the conventional servo sector. 1 when larger than the value,
When it is small, the cylinder address is read as 0, and the change of the dielectric constant in one track may be used like a conventional burst signal to perform seek and positioning control of the magnetic head. Also in this case, if the number of servo sectors is set to be sufficiently large, the servo band can be widened. Further, in the embodiment, the magnetic head is provided with two conductors, but a plurality of conductors may be integrated with the magnetic head.

Next, another embodiment will be described with reference to FIGS.

In the above-mentioned sector servo type magnetic disk device, in order to make the magnetic head on track to a desired track, that is, to follow the track, a discretized phase lead / lag delay compensator is generally used in the head positioning controller. . It is conceivable to increase the control band as a simple method to increase the positioning accuracy with such a controller.
Since it is a sampling system, it is necessary to raise the sampling frequency in order to raise the control band.

However, in the magnetic disk, increasing the servo area and increasing the sampling frequency deteriorates the format efficiency and reduces the data area. Therefore, the control band is necessarily limited by the sampling frequency. Therefore, conventionally, when designing a phase advance / lag delay compensator, in order to improve the positioning accuracy without increasing the control band, the gain for reducing the open loop characteristic of the head positioning control system is increased as much as possible, and the sensitivity is increased. This is done by increasing the suppression rate for the disk eccentricity component of the rotational drive mechanism of the function. However, when a higher head positioning accuracy is required, the presence of vibration of the magnetic disk housing due to the rotation of the rotary drive mechanism, vibration applied to the magnetic disk from the outside, etc. becomes a problem. The fixed deviation of the magnetic head caused by the torque disturbance directly applied to the VCM increases the open loop gain of the head positioning control system or increases the suppression rate of the rotational drive mechanism of the sensitivity function for the disk eccentric component. It is difficult to improve the head position determination accuracy only by itself. Therefore, in the conventional sector servo system, in order to make the magnetic head track-follow, by increasing the suppression rate of the sensitivity function for the eccentricity component of the disk and by increasing the open loop reduction gain of the head positioning control system, the positioning accuracy is increased. Was being taken to improve.

However, when the trat density becomes high due to the vibration of the housing and the vibration of the entire rotating portion of the rotational drive mechanism due to the rotational drive force of the rotational drive mechanism, the positioning accuracy is improved. Is difficult.

Therefore, in this embodiment, a track follow-up control system is constituted by a controller for generating a control signal for controlling the moving mechanism based on the position information, and the frequency component of the disturbance applied to the VCM is added to this controller. On the other hand, it has resonance characteristics and anti-resonance characteristics. This allows the magnetic head to follow the track with high precision without widening the control band of the head positioning control system.

That is, in this embodiment, as shown in FIG. 6, the rotational drive mechanism 41 rotationally drives the magnetic disk 42 having about 50 servo sectors at 4000 rpm.
The magnetic heads 43 and 44 are magnetic heads for recording / reproducing information on / from the rotationally driven magnetic disk 42.

The magnetic heads 43 and 44 are moved by the moving mechanism 4
5 is moved in the radial direction of the magnetic disk 42. The moving mechanism 45 is composed of, for example, a voice coil motor (VCM), and moves the magnetic heads 43 and 44 to a desired position on the magnetic disk 42 in the radial direction according to a control signal.

On both sides of the magnetic disk 42, the same servo sectors as those of the magnetic disk compatible with the known sector servo system are provided. As shown in FIG. 7, the servo sector includes an AGC section 51, an erase section 52 for detecting the servo sector, a track address 53 in which an address corresponding to each track is written, and a position section 54 in which a servo pattern is written. And are provided. As shown in FIG. 14, a predetermined magnetization pattern is formed in the front half a of the position portion 54 at a predetermined pitch, for example, only outside the radial center of the magnetic heads 43 and 44, and in the rear half b. A predetermined magnetization pattern is formed at a predetermined pitch only inside the running centers of the magnetic heads 43 and 44.

Of the signals reproduced by the magnetic heads 43 and 44 shown in FIG. 6, the signal at the position 54 is sampled for each servo sector and input to the amplifier 46, the AGC amplifier 47 and the sample hold circuit 48.

The sample and hold circuit 48 samples and holds the signal of the position section 54 for each sampling, and subtracts the total amount B of the power of the signal of the second half b from the total amount of power A of the signal of the first half a to obtain the position. An error signal (AB) or (BA) is generated. Further, by combining the position error signal and the track address (address area 53) unique to each track, the distance between the tracks can be calculated. For example, if the current track address is N1 and the destination track address of the magnetic head is N2, the distance is (N2
-N1) is represented by an integer value, and the position error signal (A-B) is further normalized by (A-B) / (A + B),
It can represent the distance below the decimal point.

The position error signal (AB) is input to the μCPU 50 via the A / D converter 49. μCPU50
Generates a control signal for positioning every time the position error signal (AB) is input, and sends it to the VCM drive circuit 52 via the D / A converter 51 which converts the positioning control signal into an analog signal. The VCM drive circuit 52 uses the moving mechanism 45 to move the magnetic heads 43 and 4 according to the positioning control signal.
4 to control the movement in the radial direction.

FIG. 8 shows the configuration of the position control system. In FIG. 8, the positioning mechanism 61 includes circuit elements other than the μCPU 50 in the circuit shown in FIG.

An embodiment of the positioning control system shown in FIG. 8 will be described below.

In the μCPU 50, the subtractor 62 subtracts the position error signal (AB) or (BA) obtained by the positioning mechanism 61 from the signal R (s) indicating the position to move the magnetic head, The result is input to the controller 63.
The controller 63 is composed of, for example, a discretized phase lead-lag compensator. The spectrum of the position error signal only from this controller 63 is shown in FIG. As can be seen from this spectrum, when the controller 63 constitutes a track follow-up control system and the magnetic head is on-track on the target track, the rotation of the rotary drive mechanism 41 causes the magnetic head to vibrate and cause the magnetic head to move. Tracks cannot be tracked with high accuracy. Therefore, a controller 64 having a resonance characteristic to the controller 63 for the primary and secondary components of the vibration of the magnetic disk housing due to the rotation of the rotary drive mechanism 41 is attached. That is, the controller 64 is given a resonance characteristic at a frequency that is an integral multiple of the vibration frequency of the magnetic disk housing generated by the rotation driving force of the rotation driving mechanism 41, and each Q value of this resonance characteristic is, for example, 2. It is set to 0 or more. By doing so, the VCM drive circuit 45
It is possible to form notch characteristics for the primary and secondary frequency components of vibration in the transfer function from the torque disturbance applied to the position error signal to the position error signal. The controllers 63 and 64 are shown in FIG.
Is shown, and the frequency characteristic of the transfer function from the torque disturbance to the position error signal is shown in FIG.

The spectrum of the position error signal when the controllers 63 and 64 of this embodiment are used is shown in FIG. As can be seen by comparing FIG. 12 and FIG. 9, the controller 6
By connecting a controller 64 having resonance characteristics to the primary and secondary components of the vibration of the magnetic disk housing due to the rotation of the rotary drive mechanism 41, the positioning accuracy can be improved.

Further, a controller 65 having an anti-resonance characteristic with respect to the shake of the entire rotary portion of the rotary drive mechanism 41 is attached. That is, the controller 65 is made to have the anti-resonance characteristic in the vibration frequency of the entire rotating portion of the rotary drive mechanism 41, and the Q value of this anti-resonance characteristic is set to 1.5 or less. This allows
For example, as shown in the spectrum of FIG. 9, the position error component appearing in the vicinity of 800 Hz can reduce the position error component caused by the shake of the entire rotating portion of the rotary drive mechanism 41. The sensitivity function at this time is shown in FIG.

The present invention is not limited to the above embodiment.

For example, in the above-mentioned embodiments, the case where the present invention is applied to the sector servo system has been described, but the present invention can be realized also in a system having a dedicated servo surface. Further, in the embodiment, the first and second-order components of the vibration of the magnetic disk housing due to the rotation of the rotary drive mechanism 41 are dealt with, but the same configuration can be adopted for the higher-order components. Further, for vibration components externally applied to the magnetic disk housing, the controllers 63 and 64 can be similarly configured for the vibration components to improve the positioning accuracy.

Further, it is naturally conceivable that only one of the controllers 64 and 65 is used depending on the case. Further, the controller 63 may be realized by state feedback using an observer, or may be realized by a robust controller such as an H infinity controller.

[0053]

According to the present invention, it is not necessary to secure a servo information area for head positioning in the data storable area on the magnetic disk, the format efficiency is improved and the storage capacity is increased. In addition, since the signal for head positioning is continuously and continuously obtained from the data surface,
The servo band can be widened, a highly accurate head positioning control system can be configured, the track density is improved, and the storage capacity is increased. Further, since the servo band is widened, it is possible to realize fast seek performance.

Further, according to the present invention, the controller for generating the control signal for controlling the moving mechanism based on the position information is provided with a VC.
By attaching a controller having resonance characteristics to the frequency component of the torque disturbance applied to M and a controller having anti-resonance characteristics to the shake of the entire rotating portion of the rotary drive mechanism, a track following control system is provided. The positioning accuracy of can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a magnetic disk device according to an embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement of a first area and a second area on a magnetic disk of a magnetic disk device according to an embodiment of the present invention.

3 is a cross-sectional view of the magnetic disk taken along the line AB of FIG.

FIG. 4 is a cross-sectional view in which a first region and a second region are arranged on a protective film of various magnetic disks according to an embodiment of the present invention.

FIG. 5 is a diagram for explaining a signal detected along with the movement of the magnetic head of the magnetic disk device in one embodiment of the present invention and a magnetic head positioning method using the signal.

FIG. 6 is a diagram showing a configuration of a magnetic disk device according to another embodiment of the present invention.

7 is a diagram showing the configuration of a control system of the embodiment of FIG.

FIG. 8 is a diagram showing a configuration of servo sectors on a magnetic disk.

FIG. 9 is a diagram showing a spectrum of a position error signal when a conventional magnetic head is on track.

FIG. 10 is a diagram showing frequency characteristics of a controller according to an embodiment of the present invention.

FIG. 11 is a diagram showing frequency characteristics from a torque disturbance to a position error signal according to an embodiment of the present invention.

FIG. 12 is a diagram showing a spectrum of a position error signal during on-track of the magnetic head of one embodiment to which the present invention is applied.

FIG. 13 is a diagram showing a sensitivity function of a control system of an embodiment to which the present invention is applied.

FIG. 14 is a diagram showing a configuration of servo information recorded on a magnetic disk.

[Explanation of symbols]

11 ... Magnetic head, 12 ... Magnetic disk, 13 ... Conductor, 17 ... Protective film, 18 ... First area, 19 ... Second area, 61 ... Positioning mechanism, 62 ... Subtractor, 63 ... Controller, 64 … Resonance controller, 65… Anti-resonance controller.

Claims (2)

[Claims] 1. A magnetic disk in which first regions having a first dielectric constant and second regions having a second dielectric constant lower than the first dielectric constant are alternately formed at specific intervals. ,
A magnetic head composed of a recording / reproducing head element and a conductor, which are in contact with the magnetic disk at the time of data recording / reproducing and are integrally formed; and the conductor provided on the magnetic head and the magnetic disk. A magnetic disk characterized in that an electrostatic capacitance between the magnetic head and a conductive magnetic body is detected for each of the electric conductors of the magnetic head, and the magnetic head is positioned by using these detected signals. apparatus. 2. A rotary drive mechanism for rotationally driving a magnetic disk on which position information for positioning the magnetic head is recorded in advance, and a moving mechanism for moving the magnetic head in the radial direction of the magnetic disk based on a positioning control signal. In a magnetic disk device having: a reading means for reading the positional information recorded on the magnetic disk; and a resonance characteristic at a frequency that is an integral multiple of the vibration frequency of the magnetic disk housing generated by the rotation driving force of the rotation driving mechanism. A magnetic disk device comprising: a first controller provided with the second controller; and a second controller provided with anti-resonance characteristics in the frequency of the vibration of the entire rotating portion of the rotary drive mechanism.