JPH07169226A - Magnetic disk - Google Patents

Abstract

PURPOSE:To prevent the staining of the clamp part of the magnetic recording medium surface of a magnetic disk by forming grooves in the clamp part of the magnetic disk. CONSTITUTION:The magnetic recording medium surface 6 of the magnetic disk 5 is a smooth surface kept at high precision, but grooves 9 are formed in the region of the clamp part 8 of the disk 5 having 5mm width from the edge of the inner circumferential part 7 of the disk 5 so as to attain 0.1 to 0.2mum peak roughness Rp, 3 to 50nm average roughness Ra, 0.3 to 10mum pitch and 0 to 90 deg. angle to the circumferential direction. When the grooves 9 are formed in the region of the clamp part 8, a surface which becomes the magnetic recording medium surface 6 is polished and the polished surface of the region of the clamp part 8 is ground with an abrasive tape. At least a magnetic film and a protective film are then successively laminated by sputtering. At the time of clamping the resulting disk 5 to the spindle of a disk device, the clamp part 8 and clamping parts are fixed in a linear contact or spot contact state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high density magnetic recording magnetic disk used in the information industry field and the like.

[0002]

2. Description of the Related Art A conventional magnetic disk will be described below with reference to the drawings. FIG. 3 is a plan view of a conventional magnetic disk. In FIG. 3, 1 is a donut-shaped magnetic disk, 2 is a nonmagnetic aluminum alloy substrate of the magnetic disk 1, and at least a magnetic film and a protective film are laminated on the magnetic film by applying a film by sputtering or the like. The magnetic recording medium surface 3 is an inner peripheral portion provided at the center of the magnetic recording medium surface 2, and 4 is a clamp portion for clamping the magnetic disk 1 on the spindle of the magnetic disk device.

The operation of the magnetic disk 1 having the above structure will be described below. The inner peripheral part 3 provided on the magnetic disk 1 is inserted into the spindle of the magnetic disk device, the clamp part 4 of the magnetic disk 1 is clamped and fixed by the clamp parts of the spindle, and the magnetic head is attached to the magnetic recording medium surface 2 by the rotation of the spindle. The signal is recorded by the magnetic recording medium and the recorded signal on the magnetic recording medium surface 2 is reproduced by the magnetic head.

[0004]

As described above, in the above-described conventional structure, when the clamp portion 4 of the magnetic disk 1 is fixed by the clamp component of the spindle when the characteristics of the magnetic recording medium surface 2 are inspected, the clamp portion 4 is fixed. However, due to the contact of the spindle with the clamp component, the stain of the clamp component adheres to the clamp portion 4 and the magnetic recording medium surface 2 has a poor appearance.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a magnetic disk in which the clamp portion on the surface of a magnetic recording medium is prevented from becoming dirty.

[0006]

To achieve this object, the magnetic disk of the present invention has a structure in which a plurality of grooves are provided in the clamp portion.

[0007]

With this construction, the clamp area of the magnetic disk and the clamp parts of the spindle make line contact or point contact, so that the contact area is reduced.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a magnetic disk according to an embodiment of the present invention. FIG. 2 is an enlarged sectional view of a magnetic disk according to an embodiment of the present invention. In the figure, 5 is a donut-shaped magnetic disk, and 6 is a magnetic disk in which at least a magnetic film and a protective film are stacked on the magnetic film by film formation on the non-magnetic aluminum alloy substrate of the magnetic disk 5 by sputtering or the like. A recording medium surface, 7 is an inner peripheral portion provided at the center of the magnetic recording medium surface 6, 8 is a clamp portion for clamping the magnetic disk 1 on a spindle of a magnetic disk device,
Reference numeral 9 is a groove provided in the clamp portion 8.

The magnetic recording medium surface 6 of such a magnetic disk 5 is a smooth surface kept with high precision, but in the region of the clamp portion 8 having a width of 5 mm from the end of the inner peripheral portion 7 of the magnetic disk 5. Is provided with a groove 9, and this groove 9 has a maximum roughness Rp.
0.1 to 0.2 μm, average roughness Ra of 3 to 50 n
m, the pitch is 0.3 to 10 μm, and the angle is 0 to 90 ° with respect to the circumferential direction.

To form the groove 9 in the region of the clamp portion 8 as described above, for example, after the surface to be the magnetic recording medium surface 6 is polished, the clamp portion 8 of the magnetic disk 5 is formed.
The polished surface of the region (1) is polished with a polishing tape, and then at least the magnetic film and the protective film are laminated on the magnetic film by sputtering. When the magnetic disk 5 thus formed is clamped on the spindle of the magnetic disk device, the clamp portion 8 and the clamp component are fixed in line contact or point contact.

[0011]

As described above, according to the present invention, since the clamp portion of the magnetic disk is provided with the groove, the clamp portion and the clamp component of the spindle are in line contact or point contact with each other, so that the contact area is reduced and the clamp component is removed from the clamp component. It is possible to realize a magnetic disk in which dirt on the magnetic disk is reduced and appearance defects on the surface of the magnetic recording medium are reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a magnetic disk according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a magnetic disk according to an embodiment of the present invention.

FIG. 3 is a plan view of a conventional magnetic disk.

[Explanation of symbols]

 5 Magnetic Disk 6 Magnetic Recording Medium Surface 7 Inner Circumference 8 Clamp 9 Groove

Claims (2)

[Claims] 1. A magnetic disk having a magnetic film provided on a substrate, wherein a plurality of grooves are provided in a clamp portion. 2. The groove has a maximum roughness Rp of 0.1 to 0.2 μm.
m, average roughness Ra of 3 to 50 nm, pitch of 0.3 to
2. The magnetic disk according to claim 1, wherein the magnetic disk is 10 [mu] m and the angle is 0 to 90 [deg.] With respect to the circumferential direction.