JPH0589622A - Magnetic disk device and magnetic head - Google Patents

Abstract

PURPOSE:To prevent the decline in reproduced signal output of a magnetic head using an MR element so as to improve the S/N characteristic of the magnetic head by positioning the MR element to a position deviated from the center of tracks. CONSTITUTION:This magnetic head is provided with an MR element 23 and a gap 25 for recording at a prescribed distance from the element 23. At the time of recording data, the element 23 is positioned at a point deviated from the center 29 of tracks by a prescribed off-track amount H decided by the azimuth angle so that the gap 25 can be positioned to the center of the tracks. The width of the element 23 is made smaller than the gap width of a recording head. Therefore, a decline in reproduced signal output can be prevented, since the recording head and a reproducing head are positioned in the same area. In addition, the reproduced signals have an excellent S/N, since the reproducing head does not read an area where no data are recorded at the time of reproduction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an MR as a reproducing head.
The present invention relates to a magnetic disk device and a magnetic head using an element.

[0002]

2. Description of the Related Art Recently, in hard disk devices,
With the demand for small size and high capacity, downsizing of disks is desired. Since the medium speed decreases as the disk diameter decreases, there is a problem in that when an inductive head whose output is proportional to the medium speed is used, the output decreases and good S / N characteristics cannot be obtained.

For this reason, attention is paid to a magnetic head using an MR element whose output does not depend on the medium speed and which can obtain a high output. Although such a head is generally called an MR head, a head using an MR element is a read-only head and recording is performed using a conventional inductive head.

FIG. 9 is a vertical sectional view of such an MR head 107. In the figure, 101 is an MR element used as a reproducing head, 103 is a recording gap, and 10 is a recording gap.
Reference numeral 5 represents a coil. An offset L is provided between the MR element 101 and the recording gap 103.

FIG. 10 is a plan view of the MR head 107. The MR head 107 records / reproduces data on / from a track 108 of a sector servo type magnetic disk. θ represents the azimuth angle.

FIG. 11 is an enlarged schematic view of a portion A of FIG.

[0007]

When recording is performed by such an MR head, as shown in FIG. 11, since recording is performed by the recording gap 103, data is recorded in the area 10.
9 is recorded.

That is, the MR element 101 is the track 10
The servo information recorded therein is read from the servo area of each sector of No. 8, and the head is positioned at the center of the track 108 so that the position error signal becomes "0". In this positioning state, the recording gap 10
3 is at a position H = Lsin θ (1) off track with respect to the track, and data is written at this position. Therefore, the data is recorded in the area 109.

For example, when the offset amount is 4 μm and the maximum value of the azimuth angle is 12 °, the off-track amount H is H = 4 × sin12 ° = 0.83 μm.

This off-track amount becomes a large value that cannot be ignored as the TPI (track per inch) becomes higher. With 2500 TPI, the track pitch is 10 μm, and about 10% of this is off-track.

Thus, the offset L and the azimuth angle θ
Due to the presence of, the recording area 109 is recorded at a position displaced from the track 108. Therefore, the MR element 10
When the reproduction is performed at 1, the data in the overlapping area of the recording area 109 and the reproduced area 111 is reproduced, so that the reproduction output becomes small. Data is not recorded in the hatched area 113, but this area 113 is
Since the R element 101 reads, noise in this area 113 may be read and the S / N of the reproduced signal may decrease.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a magnetic disk device in which the output of a reproduced signal does not decrease, and an S / N of the reproduced signal.
To provide a good magnetic head.

[0013]

In order to achieve the above-mentioned object, a first aspect of the present invention is to record an MR element and a position at a predetermined distance from the MR element with a gap width substantially the same as the width of the MR element. In a magnetic disk device for recording / reproducing data to / from a track of a magnetic disk with a magnetic head having a gap, the MR element is arranged so that the recording gap is positioned at the center of the track when recording data. A magnetic disk drive is provided with a positioning means for positioning at a position deviated from the center of the track.

A second aspect of the present invention is a magnetic head having an MR element and a recording gap having a gap width substantially the same as the width of the MR element at a position separated from the MR element by a predetermined distance. The width of the magnetic head is smaller than the gap width of the recording head.

[0015]

In the first aspect of the invention, the recording head and the reproducing head are positioned in the same area by reproducing the magnetic head by offsetting the off-track amount during recording and reproducing without reproducing the magnetic head during reproduction. It is possible to prevent the output from decreasing.

In the second invention, since the gap width of the reproducing head using the MR element is set smaller than the gap width of the recording head, the reproducing head can read an area in which no data is recorded during reproduction. And the reproduced signal has a good S / N.

[0017]

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

FIG. 1 is a block diagram showing a schematic configuration of a magnetic disk device according to an embodiment of the present invention. As shown in the figure, this magnetic disk device includes a magnetic disk 1, a magnetic head 3, a carriage 5, a voice coil motor (VCM) 7, an amplifier 9, a read / write circuit 11, and an EN.
DEC13, HDC15, servo circuit 17, CPU1
9 has a driver 21. CE in the figure indicates the center of rotation of the carriage 5.

The magnetic head 3 records / reproduces data on / from the magnetic disk 1. This magnetic head 3 is shown in FIG.
And an MR head having the same structure as the head shown in FIG. The carriage 5 swings around the rotation center CE. The VCM 7 drives the carriage 5 according to a command from the driver 21 and moves the magnetic head 3 in the radial direction.

The amplifier 9 adjusts the gain of the signal read by the magnetic head 3 and the signal sent to the magnetic head 3. The read / write circuit 11 digitally converts the signal sent from the amplifier 9 and converts the write signal sent from the ENDEC 13 into an analog signal. END
The EC 13 decodes the reproduction signal and sends it to the HDC 15, and also encodes the write signal sent from the HDC 15.
The HDC 15 is connected to the host computer.

The servo circuit 17 reads only the servo signal among the read signals sent through the amplifier 9,
The position error signal is sent to the CPU 19. The CPU 19 drives the driver 21 according to this position error signal to position the carriage 5 at a predetermined position. And the CPU 19
Calculates an off-track amount H that changes according to the azimuth angle (yaw angle), and moves the magnetic head 3 during recording to perform recording.

FIG. 2 is a diagram showing the operation of the present invention.
FIG. 2A shows the position of the magnetic head during recording. In the figure, 27 are a plurality of tracks provided concentrically on the magnetic disk 1. This track is divided into multiple sectors. Further, each sector is divided into a servo area in which servo data used for positioning the magnetic head is recorded and a data area in which a user records and reproduces data. 29 indicates the center of the track 27. At the time of recording, the MR element 23 reads the servo signal written in the track 27, and the position error signal of the magnetic head 3 is sent to the CPU 19 via the servo circuit 17.

The CPU 19 calculates the off-track amount H as follows. As described above, the off-track amount H and the azimuth angle θ have a relationship of H = Lsin θ (1). The azimuth angle θ changes as the magnetic head 3 moves in the radial direction of the magnetic disk 1. Therefore, the off-track amount changes as the azimuth angle θ changes. The CPU 19 obtains the off-track amount H based on the equation (1) according to the position of the track on which the magnetic head 3 is currently positioned.

Then, the CPU 19 drives the driver 21 by adding the calculated off-track amount H to the position error signal.

That is, while the MR element 23 is positioned so that the position error signal becomes "0" in a normal magnetic disk device, in this embodiment, as shown in FIG. The MR element 23 is positioned at a position deviated from the track center 29 by an off-track amount H. Accordingly, the center of the recording gap 25 is the track center 29.
Then, data is recorded on the track 27 by the recording gap 25. FIG. 2B shows the position of the magnetic head during reproduction. During reproduction, the MR element 23
The servo signal is read by the servo circuit 17
The position error signal of the magnetic head 3 is sent to the CPU 19 via. The CPU 19 drives the driver 21 so that this position error signal becomes "0". As a result,
As shown in (b), the center of the MR element 23 coincides with the track center, and the data recorded on the track 27 is read by the MR element 23.

Thus, in this embodiment, the recording gap 2
Since the recording area of No. 5 and the reproduction area of the MR element 23 coincide with each other, a high output can be obtained during reproduction. FIG. 3 is a schematic view of a magnetic head according to the second invention. This magnetic head has almost the same structure as the magnetic head shown in FIGS.
Is the gap width W ₁ of the recording gap 25.
It is set narrower than ₂ . In the figure, ψ = 15
° is desirable. This is because the maximum value of the azimuth angle of the magnetic disk device using the rotary actuator is about 15 °. The structure of the magnetic disk device having this magnetic head is the same as that shown in FIG.

FIG. 4 is a diagram showing the movement of the magnetic head in the radial direction in a magnetic disk device using this magnetic head. A indicates the innermost position, B indicates the central position, and C indicates the outermost position.

FIG. 5 is a diagram showing a recording area and a reproducing area when such a magnetic head is used.

Now, the operation of the magnetic head 3 in the position C will be described. When recording, M
The servo signal written in the area 31 is read by the R element 23, and the CPU 19 is read via the servo circuit 17.
The position error signal of the magnetic head 3 is sent to. CPU19
Drives the driver 21 to position the recording gap 25 at the center of the track 31, and then records data on the track 31 at the recording gap 25.

During reproduction, the MR element 23 reads the servo signal, and the position error signal of the magnetic head 3 is sent to the CPU 19 via the servo circuit 17.
The CPU 19 drives the driver 21 so that the position error signal becomes “0”, and the MR element 23 reads the data recorded in the area 33.

By the way, in this embodiment, as shown in FIG. 5, since the gap width of the MR element 23 is narrower than the gap width of the recording gap 25, the innermost circumference, the center,
Since the reproduction area 33 does not extend beyond the recording area 31 at any position on the outermost periphery, the MR element 23 does not read an area in which no data is written, and the reproduction signal has a high S / N.

FIG. 6 shows another embodiment of the second invention. In this embodiment, the gap width of the MR element 41 is made narrower than the gap width of the recording gap 43. Then, as shown in FIG. 6, ψ is provided only on one side.

FIG. 8 is a diagram showing the movement of the magnetic head shown in FIG. 6 in the radial direction.

FIG. 9 is a diagram showing a recording area and a reproducing area when this magnetic head is used. As shown in the figure,
Also in this embodiment, since the gap width of the MR element 41 is narrower than the gap width of the recording gap 43,
Since the reproducing area does not extend beyond the recording area at either the innermost or outermost position, the MR element 41 does not read the area in which no data is written and the reproduced signal has a high S / N. ..

[0035]

As described above in detail, according to the present invention, the magnetic disk device in which the output of the reproduction signal does not decrease,
Further, it is possible to provide a magnetic head having a good S / N of a reproduction signal.

[Brief description of drawings]

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

FIG. 2 is a diagram showing the position of a magnetic head during recording and reproduction.

FIG. 3 is a schematic diagram of a main part of a magnetic head according to a second invention.

FIG. 4 is a diagram showing movement of a magnetic head in a radial direction.

5 is a diagram showing a recording area and a reproducing area when the magnetic head shown in FIG. 3 is used.

FIG. 6 is a schematic diagram of a main part of a magnetic head according to another embodiment of the second invention.

FIG. 7 is a diagram showing movement of a magnetic head in a radial direction.

FIG. 8 is a diagram showing a recording area and a reproducing area when the magnetic head shown in FIG. 6 is used.

FIG. 9 is a vertical sectional view of a conventional magnetic head.

FIG. 10 is a plan view of the MR head 107.

11 is an enlarged schematic view of part A of FIG.

[Explanation of symbols]

 1 ... magnetic disk 3 magnetic head 5 carriage 7 VCM 9 amplifier 11 read / write circuit 17 servo circuit 19 CPU 21 driver 23, 41 ... MR element 25, 43 ... Recording gap

Claims (2)

[Claims] 1. A magnetic head provided with an MR element and a recording gap having a gap width substantially the same as the width of the MR element at a position separated from the MR element by a predetermined distance, thereby recording data on a track of a magnetic disk. In a magnetic disk device for reproduction, when recording data, the M is set so that the recording gap is positioned at the center of the track.
A magnetic disk drive comprising a positioning means for positioning the R element at a position displaced from the center of the track. 2. A magnetic head having an MR element and a recording gap having a gap width substantially the same as the width of the MR element at a position separated from the MR element by a predetermined distance. A magnetic head characterized by being provided smaller than the gap width of the recording head.