JPH04313810A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To smoothly start and to decrease the noise of a servo positioning signal by making noncoincident the grinding locus of the texture of magnetic disk media in space and time manners to the locus of a magnetic head. CONSTITUTION:When texture is formed at a magnetic disk substrate, the pat position of a grinding tape and the rotating center of a magnetic disk substrate are dislocated, and magnetic disk media 9 are made. Thus, a grinding locus 8 of the texture can be 5 degrees or above for an odd number die pulse signal 6 and an even number die pulse signal 7 recorded on the media 9. By such a constitution, the texture grinding locus 8 is not continued for an odd number die pulse 6 and an even number die pulse 7 and occurs on the average. The noise of the servo position signal becomes widely small and the starting can be smoothed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo surface servo type magnetic disk device, and more particularly to a magnetic disk device used in large-capacity file devices for computers.

0002

2. Description of the Related Art Generally, a magnetic disk device used as a large-capacity file device for a computer requires a magnetic head to operate at high speed in order to record/reproduce data at high speed. In order to operate this magnetic head at high speed,
It is implemented by combining a voice coil motor (hereinafter simply referred to as VCM) and a magnetic disk medium on which servo signals are recorded (hereinafter simply referred to as servo surface servo). In this magnetic disk device, the magnetic head and magnetic disk medium come into contact when the device is started or stopped (hereinafter referred to as CSS), but if the magnetic disk device is stopped for a long time or the number of CSS increases, the magnetic head will contact the magnetic disk medium. If they stick together, the magnetic disk medium will stop rotating and the magnetic disk device will not start up, causing a so-called adhesion phenomenon. Therefore,
Conventionally, as shown in FIGS. 5 and 6, a magnetic disk medium 1 uses a substrate 2 (hereinafter simply referred to as a textured substrate) on which grooves 2a are textured in the circumferential direction using an abrasive tape (not shown). A magnetic film 3 and a protective film 4 are formed on this textured substrate 2 by sputtering or plating. Therefore, the magnetic film 3 and the protective film 4 are also formed in a wave shape similar to the shape of the textured substrate 2 to prevent the magnetic head from being attracted. In this way, the texture polishing locus 5 is formed in the circumferential direction of the magnetic disk medium. Note that FIG. 6(B) shows the positional relationship of the texture polishing locus 5 with respect to the odd-numbered die pulse 6 and the even-numbered die pulse 6 recorded on the magnetic disk medium 1.

0003

Problems to be Solved by the Invention In this conventional magnetic disk device, servo signals (
The servo positioning signal (hereinafter simply referred to as position signal) becomes irregular, and the servo positioning signal (hereinafter simply referred to as position signal) becomes irregular.
A large noise voltage is generated as shown in FIG. Therefore, if the roughness of the textured substrate is reduced in order to reduce this noise voltage, there is a problem in that the magnetic head is attracted to the magnetic disk medium, causing a serious problem such as the magnetic disk device not starting up.

0004

[Means for Solving the Problems] A magnetic disk device according to the present invention uses a magnetic disk medium formed such that the polishing trajectory of the texture is spatially/temporally inconsistent with the trajectory of the magnetic head. It is.

[0005]

According to the present invention, it is possible to reduce the noise in the magnetic disk medium position signal output from the magnetic disk device.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a plan view showing an embodiment of a magnetic disk medium used in a magnetic disk device according to the present invention. In particular, the trajectory of the magnetic head, that is, the texture polishing trajectory for the odd-numbered die pulse 6 and the even-numbered die pulse 7. 8 are spatially mismatched, and as an example, the polishing locus 8 of the texture is formed at an angle of 5 degrees or more with respect to the circumferential direction, that is, the rotation locus of the magnetic head. The noise voltage of the servo position signal of this magnetic disk device can be made very small as shown in FIG.

As shown in FIG. 3, the method for manufacturing the magnetic disk medium 9 is to shift the position of the pad of the abrasive tape from the center of rotation of the magnetic disk substrate, which is called eccentricity, when forming the texture on the magnetic disk substrate. It can be manufactured by As a result, as shown in FIG. 1B, the texture polishing locus 8 can be set at 5 degrees or more with respect to the odd-numbered dipulse signal 6 and the even-numbered dipulse signal 7 recorded on the magnetic disk medium 9.

FIG. 4 is a plan view showing another embodiment of the magnetic disk medium used in the magnetic disk device according to the present invention, in particular, the trajectory of the magnetic head, that is, the texture polishing trajectory for the odd-order die pulse 6 and the even-number order die pulse 7. 8 are temporally inconsistent; for example, the polishing locus 8 is formed discontinuously in the circumferential direction, and when the polished portion 10a is 2 cm, the non-polished portion 10b
is formed to be 2 cm or more. The noise voltage of the servo position signal of this magnetic disk device can be made very small as shown in FIG.

The magnetic disk medium 9 can be manufactured by vibrating an abrasive tape (not shown) in a direction perpendicular to the circumferential direction when texture is formed on the magnetic disk substrate. As a result, Figure 4
As shown in (B), the texture polishing trajectory 8 is not continuous with respect to the odd-numbered die pulse 6 and the even-numbered die pulse 7 recorded on the magnetic disk medium, but is generated on the average.

0010

[Effects of the Invention] As described above in detail, according to the magnetic disk device according to the present invention, the polishing trajectory of the texture can be formed so as to be spatially/temporally inconsistent with the trajectory of the magnetic head. This has the effect of significantly reducing noise in the servo position signal and smoothing startup.

[Brief explanation of drawings]

FIG. 1 is a plan view showing one embodiment of a magnetic disk medium used in a magnetic disk device according to the present invention.

FIG. 2 is a waveform diagram showing noise in a position signal output from the magnetic disk device shown in FIG. 1;

FIG. 3 is a plan view of the magnetic disk medium for explaining a method of manufacturing the magnetic disk medium shown in FIG. 1;

FIG. 4 is a plan view showing another embodiment of the magnetic disk medium used in the magnetic disk device according to the present invention.

FIG. 5 is a cross-sectional view of a magnetic disk medium with grooves formed by conventional texture polishing.

FIG. 6 is a diagram showing the positional relationship between the trajectory of a magnetic head and the trajectory of texture polishing in a conventional magnetic disk medium.

FIG. 7 is a waveform diagram showing noise in a position signal output from a conventional magnetic disk device.

[Explanation of symbols]

6 Odd-order dipulse 7 Even-order dipulse 8 Texture polishing trajectory 9 Magnetic disk media

Claims (1)

[Claims] Claim 1: In a magnetic disk device that records/reproduces information on a magnetic disk medium using a servo surface servo method, the polishing trajectory of the texture is formed so as to be spatially/temporally inconsistent with the trajectory of the magnetic head. What is claimed is: 1. A magnetic disk device comprising a magnetic disk medium.