JPS62293515A - Production of magnetic disk - Google Patents

Abstract

PURPOSE:To prevent a liquid sag from remaining on the main surface of a disk when the disk is pulled up from a liquid lubricating agent by forming a groove to at least either of the inside and outside peripheral end faces of the disk and immersing the disk into the lubricating agent, thereby forming a lubricating layer on the disk surface. CONSTITUTION:The groove 2 is formed to the inside and outside peripheral end faces of the disk 1. The groove 2 is formed to 0.5mm width and 1mm depth with respect to 2mm thickness, 130mm diameter and 40mm inside diameter of the toric disk 1. Thus, the lubricating agent is drawn much into the groove 2 by surface tension and flocculates therein when the lubricating agent is coated to the disk 1 by a dipping method. As a result, the balance between the weight of the lubricating agent and the surface tension, etc., is broken and the lubricating agent is considered to drop by failing to remain on the main surface of the disk. The generation of the liquid sag on the main surface of the disk is thus obviated. The magnetic disk which is free from the uneven thickness of the lubricating agent is, therefore, obtd.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a recording medium for magnetic recording, particularly to what is called a rigid disk.

[Conventional technology]

Generally, when performing backyard magnetic recording using a rigid disk (hereinafter referred to as a disk), contact with a magnetic head (hereinafter referred to as a head) becomes a problem.

This will be explained below. During actual recording and reproduction, the disk rotates, and the head is therefore lifted by airflow. However, when recording and reproduction are finished, that is, when the disk starts to stop from rotating, the head starts contacting the disk from a floating state.

At this time, the impact generated on the head and disk must be alleviated. Therefore, ordinary disks are provided with a lubricating effect. For example, in the general disk shown in Figure 2, when a metal magnetic M (1b) is used as the magnetic recording layer, it is not directly exposed and brought into contact with the head, but rather a lubricating layer (3 ) is provided on the metal magnetic layer (1b). In the figure, (1) is an annular disk, that is, a disk, and (yua) rri substrate. Lubricant layer′
For example, when using a liquid lubricant, the method for providing fe can be roughly divided into two: rotating a disk to apply the lubricant'! There are two methods: a spin cord method in which the disc is coated with i7, and a dipping method in which the disc is immersed in a lubricant and then pulled up.

[Problem that the invention seeks to solve]

Here, although the derubbing method is generally simpler than the spin code method, it has a problem in that so-called "drip" occurs. This will be explained using all the figures. Third
The figures are a front view and a side view enlarged in the thickness direction of a magnetic disk that has been subjected to a lubricant coating process using a dipping method in a conventional magnetic disk manufacturing method. When the annular disk (1) is completely immersed in a liquid lubricant and pulled up vertically, due to the surface tension of the lubricant, a portion where too much lubricant is applied locally, that is, a drip (4), occurs.

If a liquid drip occurs, when the lubricant dries, the thickness becomes uneven and the contact between the disk and the head becomes unstable, which poses a major problem during recording and reproduction. This was done in order to solve this problem, and it is our aim to provide a method for manufacturing magnetic disks that can completely prevent dripping when lifted from liquid lubricant by applying di-lubricant treatment using the dipping method. The purpose is

[Means for solving problems]

In the method for manufacturing a magnetic disk according to the present invention, a groove is formed on at least one of the inner and outer circumferential end surfaces of the disk, and the groove is immersed in a lubricant to form a lubricant f'R layer on the surface of the disk.

[Effect]

Since the magnetic disk according to the present invention has grooves formed on at least one of the inner and outer circumferential end surfaces of the disk, a large amount of the lubricant is drawn into the grooves due to surface tension and aggregates, resulting in the weight of the lubricant and the It is thought that the balance of tension etc. is broken and the lubricant cannot remain on the main surface of the disk and falls, so no dripping occurs.

〔Example〕

FIG. 1 is a plan view showing a magnetic disk according to a method of manufacturing a magnetic disk according to an embodiment of the present invention, and a side view enlarged in the thickness direction. ) is a groove provided on the inner circumferential side and outer circumferential side. In this case, the thickness of the annular disk (1) is 2 mm.
, the diameter was 130 mm, the inner diameter was 40 mm, the groove (2) was 0.5 mm, and the depth was 1 mm. When lubricant is completely applied to a magnetic disk with such a structure using the dipping method,
Almost no liquid dripping occurred on the main surface of the disk. As the lubricant, for example, 1 wt % or less of perfluoroalkyl sulfo/acid or perfluoroalkyl carboxylate (manufactured by Dainippon Ink Chemical Co., Ltd.) dissolved in alcohol water was used as a solvent.

In the above embodiment, the grooves (2) were provided on the inner and outer circumferential surfaces of the annular disk (1), but the same effect can be achieved by using only the outer circumferential side surfaces.

Furthermore, even when the groove (2) is provided only on the inner circumferential side surface, the lubricant is drawn into the groove (2) and the same effect can be obtained.

Furthermore, it is clear that the same effect can be obtained by providing grooves (2) on at least one of the inner and outer circumferential ends of the main surface, as long as the grooves (2) are not in contact with the head, to draw in the lubricant.

〔Effect of the invention〕

As explained above, according to the present invention, a groove is formed on at least one of the inner and outer peripheral end surfaces of the disk, and the groove is immersed in lubricant to form a lubricant layer on the disk surface. It can prevent so-called drips that collect,
This has the effect of providing a method for manufacturing a magnetic disk without uneven lubricant floating.

[Brief explanation of drawings]

FIG. 1 is a front view and a side view enlarged in the thickness direction of a disk according to a method of manufacturing a magnetic disk according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a general magnetic disk, and FIG.
The figures are a front view and a side view enlarged in the thickness direction of a disc related to a conventional judgment. (1)...Annular disk, (2)...Groove, (3)
. . . Lubricating layer, (4) . . . dripping. Note that the same reference numerals in the drawings indicate the same or corresponding parts.

Claims (3)

[Claims] (1) A method for manufacturing a magnetic disk, in which a groove is formed on at least one of the inner and outer circumferential end surfaces of the disk, and the disk is immersed in a lubricant to form a lubricant layer on the surface of the disk. (2) The method for manufacturing a magnetic disk according to claim 1, wherein the inner and outer circumferential end surfaces are inner and outer circumferential side surfaces. (3) The method for manufacturing a magnetic disk according to claim 1, wherein the inner and outer peripheral end surfaces are outer peripheral ends of the main surface.