JPS63113986A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To attain a highly accurate positioning even when the change, etc., of an ambient temperature are executed by detecting a position dislocation from a data track center for respective data heads from the reading voltage of respective data heads and correcting a position for the data. CONSTITUTION:The value of the reading voltage of a magnetic head detected by a reading voltage detecting device 17 and an A/D converter 18 is stored in a position control device 20 including the change from the inner circumference to the outer circumference of a magnetic disk for each head 1a. For example, when the difference between a detecting reading voltage Vf of a No.200 data track and a reading voltage Ve of the data track stored is larger than an error voltage VN, the control device 20 outputs a position correcting signal to an off-set signal generating device 19 so that the voltage Vf can be maximum and executes the positioning to the data track center of the head 1a. The correcting quantity to occur at this time is stored into the control device 20 and the positioning from the next time is executed first by the correcting quantity stored.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and particularly to positioning of a magnetic head thereof with respect to a data track of a magnetic disk.

[Conventional technology]

FIG. 4 is an explanatory diagram showing the basic structure of a magnetic disk device a. In the figure, (1) is a magnetic head, (2) is a magnetic disk made of a disc made of aluminum alloy or the like coated with magnetic material powder, and (3) ) is (i[carriage that moves the head (1) in the radial direction above the magnetic disk (2), (4
) is a motor that drives the carriage (31), (5) is a spindle motor that rotates the magnetic disk (2) at a constant speed, and (6) holds the carriage (3), motor (4), and spindle motor (5). It is the base.

Information is recorded and reproduced on concentric data tracks formed on a magnetic disk (2) rotated at a constant speed by a spindle motor (5), using a magnetic head lit that moves in the radial direction of the magnetic disk (2). It will be done.

As a method for positioning the magnetic head (1) in the radial direction of the magnetic disk (2), an oven loop control method is used in which a stepping motor is used as the drive motor (4) of the carriage (3) and the step angle is determined.
Using a voice coil motor etc. as the drive motor (4),
- There is a closed-loop servo system in which position information is recorded in advance on at least one surface of a set of magnetic disks (2), and the position information is determined based on the position information from the magnetic head (1). The magnetic head (1) used exclusively for this positioning is called a servo head.

Figure vJ5 is a block diagram showing the configuration of a closed-loop servo type magnetic head positioning mechanism of a conventional magnetic disk device. In the figure, (1a) is a magnetic head for recording and reproducing 1H information, which is called a data head. (lb)
is a magnetic head for reproducing positional information, which is called a servo head, a data head (1a), and a servo head (1
When referring to other names including b), it is referred to as ``low air head (1)''.

(4) is a motor that drives the carriage to which the magnetic head (1) is fixed, (7) is a read/write amplifier connected to the data head (1a), and (8) is connected to the read/write amplifier (7). Read/analog converter for analog/digital and digital/analog conversion of recorded/playback data
Write circuit, (9) is read amplifier connected to servo head (1b), (10) is amplified servo head (1b)
1b) is a position detector that detects the position of the magnetic head (1) from the output, (11) is a position controller that controls the position of the magnetic head (1), (12) is a read/write circuit (8),
An interface circuit connected to the position controller (11) and transmitting and receiving signals with the host device, (13) a speed generator that generates a target speed signal when the magnetic head (1) moves at high speed, and (14) a Position detector (10), position controller (1
1) and a speed generator (13), the position signal;
A synthesizer (15) that synthesizes speed signals is a drive circuit that drives the motor (4).

Movement of the data head (1a) for recording and reproducing information is performed as follows.

When the interface circuit (12) receives the address of the data track on which information is to be recorded and reproduced from the host device, it instructs the position controller (11) to move the magnetic head (1). The position controller (11) calculates the difference between the current position of the servo head (1b) and the position of the data track of the designated moving target, and causes the speed generator (13) to move the magnetic head (1). generate a signal for The synthesizer (14) combines the speed signal from the speed generator (13) and the position [
B. Combines the position signals of the current position of the magnetic head (1) from the detector (10), and accelerates and decelerates the roller ridge (3) for moving the magnetic head (1) to the target data track position. The I/O signal is output to the drive circuit (15) to perform high-speed positioning of the magnetic head (1) to near the target data track position. Near the target data track, the output of the servo head (1b) detects minute positional deviations, and the magnetic head (1b) is placed in the center of the data track.
) is controlled so that it is positioned.

[The problem that the defense attempts to solve]

A conventional magnetic disk device is configured as described above, and the positioning of the magnetic head in the magnetic disk radial direction is
It is controlled only by the position information of the servo head,
When the environment such as the operating temperature of the device changes, a relative positional shift occurs between the data head and the servo head, and the position g of the data head deviates from the center of the data track, resulting in unreliable recording and reproduction of information. There was a problem in that it led to sexual deterioration. This also means that the magnetic disk
It was also an impediment to densification.

This invention has been made to solve the above problems, and aims to provide a magnetic disk device that is not affected by changes in the environment and has high reliability in recording and reproducing information.

[Means for solving problems]

The magnetic disk position according to the present invention includes means for detecting and storing the read magnetic pressure of an arbitrary data track, and changes in the read ed pressure of an arbitrary data track from a pre-stored read magnetic pressure of the data track. Accordingly, the positional deviation of the data head from the center of the data track is detected, and the position of the data head is corrected.

[Effect]

In the magnetic disk according to the present invention, the direct positioning of each data head is also corrected based on the information on the deviation from the center of the data track of the data head itself. Even if a relative misalignment develops between the head and the data head, the data head will be accurately positioned, improving information recording and horse owner reliability.

[Embodiments of the invention]

FIG. 1 is a block diagram showing one embodiment of the present invention,
In the figure, the symbols and direction symbols in FIG. 5 indicate the same or corresponding parts, and (16) occurs once every rotation of the spindle motor (5) that rotates the magnetic disk (2) at a constant speed. an index signal detector (1) for detecting an index signal indicating the start of a data track for
7) A read voltage detector connected to the beam read/write amplifier (7) to detect the read voltage of the data head (1a); (18) digitally converts the output of the read width pressure detector (17); (19) is an offset signal generator that generates a signal to minutely change the position of the data head (1a), (20) is an A/L) converter (18)
Read the output of? (2) A position controller equipped with a means for detecting a positional deviation of the data head (1a) from a change in pressure and outputting a position correction signal to an offset signal generator (19).

FIG. 2 is a waveform diagram showing the timing of the operation of the device shown in FIG.
The index signal tBl, which is generated once every rotation of the index signal and indicates the start of a data track, is a timing signal that is generated for a certain period of time from the rise of the index signal, and serves as a gate signal for the period during which the read voltage is sampled and held. C) is a read voltage obtained from the data head (1a), and generally a stable data pattern is recorded during the period of the timing signal (]3). 11)) is the read voltage te
This value is A/
, L) to detect the Yomimura Bo pressure.

The read voltage detector (17) and *ω converter (18) detect the read voltage value of the data head (1a) as described above for each data head (1a). Changes from the inner circumference to the outer circumference of the disk (2) are stored in the position controller (20).

FIG. 3 is a graph showing an example of changes in read voltage at the inner and outer circumferences of a magnetic disk, where the horizontal axis shows the track number and the vertical axis shows the read voltage.

In the figure, E) indicates the read voltage when the magnetic head (1a) is located at the center of the data track, and [Fl] indicates the appropriate read voltage when the magnetic head (1a) is out of position.

For example, the detected reading voltage Vf of the data track 200 mentioned above
and the read voltage V of the stored data track,
When the difference V, -Vf becomes larger than the error width pressure vN due to noise of the readout voltage, the position controller (20
) determines that the magnetic head (1a) has deviated from the center of the data track. (1a) Positioning is performed to the center of the data track.

The correction amount generated at this time is stored in the positioning device (20), and positioning from the next time onwards is first performed using the stored correction amount.

Further, the stored value of the read voltage is updated to a higher voltage when a higher read voltage is obtained after correction.

As described above, the positional deviation from the center of the data track is detected and corrected for each data head (1a).

In addition, although the above embodiment shows an example in which the A/D converter (18), offset signal generator (19), and position controller (20) are separated, it is also possible to incorporate these into a microcomputer. good.

In addition, although the embodiment described above is applied to a closed-loop servo type magnetic disk device, an oven-loop type magnetic disk device using a stepping motor or a torque motor may also be used, and it is also applicable to an optical disk device. has the same effect.

〔Effect of the invention〕

As described above, according to the present invention, the vertical deviation from the data track center for each data head is detected from the read voltage of the valley data head, and the position is corrected for each data rad. Even if there is a shift in the relative position between each data head due to changes,
Since positioning is performed with high precision, the reliability of recording and reproduction is improved.

[Brief explanation of the drawing]

, 111 is a block diagram showing an embodiment of the present invention, FIG. 2 is a waveform diagram showing the timing in the operation of the device shown in FIG. 1, and FIG. A graph diagram showing an example of the change, FIG. 4 is a schematic diagram showing the basic structure of a magnetic disk drive, and FIG. In the figure, (1a) is the data head 1. (lb) is the servo head, (4) is the motor, (7) is the beam read/write amplifier, (8) is the read/write circuit, and (9) is the data head. Read amplifier, (lO) is position detector, (12) is interface circuit, (13) is speed generator, (14) is synthesizer, (
15) is the drive circuit, (16) is the index signal detector, (17) is the readout voltage detector, (18) is the A/1) converter, (19) is the offset signal generator, and (20) is the position side. It is a control device. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (2)

[Claims] (1) In a magnetic disk device that uses a magnetic head to record and reproduce information on concentric data tracks of a magnetic disk, there is a means for detecting and storing the read voltage of any data track, and a means for detecting and storing the read voltage of any data track. A magnetic disk characterized by comprising means for detecting a positional deviation of a magnetic head from the center of a data track based on a fluctuation from a pre-stored read voltage of the data track, and correcting the position of the magnetic head. Device. (2) The means for detecting and storing the read voltage of an arbitrary data track samples and holds the read voltage of the data track within an arbitrary period from the index signal that is generated once every rotation of the magnetic disk. 2. A magnetic disk device according to claim 1, wherein said voltage is converted from analog to digital and stored.