JPS6334729A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain excellent recording/reproducing characteristics by vibrating a magnetic field in a direction parallel with a magnetic coat surface. CONSTITUTION:A magnetic coating material obtained by dispersing magnetic powder uniformly is applied to the surface of a base while rotating the base to obtain a fixed film thickness. Before the magnetic coat film on the base dries out completely, a magnetic disk 1 is constantly rotated at 10-500rpm by a spindle 6. Under said state, magnetic poles 2a, 3a, and 2b, 3b arranged separatedly from the magnetic coat surface of the magnetic disk 1 by 0.5-4mm distance are vibrated in accordance with a time chart shown in a graph. Since the magnetic powder in the magnetic coat film is sharply vibrated at the initial stage, the vibration is converged and its directivity is gradually integrated, the magnetic power can be arranged uniformly in the circumferential direction of the medium base. Thereby, an angular ratio can be improved and a uniform and smooth magnetic coat film can be formed.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for manufacturing a magnetic recording medium, and in particular to an m-field orientation process suitable for improving the squareness ratio of a magnetic coating film in flexible disks and hard disks. The present invention relates to a method of manufacturing a magnetic recording medium having the following.

[Conventional technology]

As the magnetic field orientation method in the conventional manufacturing method of magnetic recording media, there is a method in which a perpendicular magnetic field is applied to the surface of the magnetic coating film before hardening of the magnetic coating film, and a method as described in JP-A-56-80833. TIaVi! generates a perpendicular magnetic field when applying a perpendicular magnetic field to the magnetic coating surface. , which vibrates in a direction perpendicular to the magnetic coating surface is known.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, the magnetic powder in the magnetic coating film is made uniform in the direction perpendicular to the surface of the magnetic coating film (Japanese Patent Laid-Open No. 56-80
The invention described in Publication No. 833) has been made.

However, no efforts have been made to make the magnetic powder uniform within the magnetic coating film in the direction horizontal to the magnetic coating surface, and the orientation efficiency of the magnetic powder is poor, making it difficult to obtain a magnetic recording medium with a good squareness ratio. The problem was that there was no.

The present invention was developed in view of the problems of the prior art described above, and it makes the magnetic powder in the magnetic coating film uniform in the direction horizontal to the magnetic coating surface, improves the squareness ratio, and achieves good recording and reproducing characteristics. The object of the present invention is to provide a method for manufacturing a magnetic recording medium that can be obtained.

[Means for solving problems]

In the method for manufacturing a magnetic recording medium of the present invention, before the magnetic coating film applied on a rotating substrate dries, a magnetic field is applied to the surface of the magnetic coating film in the perpendicular and horizontal directions, or in either one direction. It has a process of orienting the magnetic powder in the coating film, and is particularly characterized by vibrating the magnetic field in a direction parallel to the surface of the magnetic coating film.

[Effect]

According to the present invention, before the magnetic coating film dries, the magnetic field applied in the direction perpendicular to the magnetic coating film surface vibrates in the horizontal direction to the magnetic coating film surface. Therefore, the magnetic powder is oriented within the magnetic coating film in a direction horizontal to the surface of the magnetic coating film, and as a result, the squareness ratio is improved, making it possible to obtain a uniform and smooth magnetic recording medium.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to embodiments shown in the accompanying drawings.

FIG. 1(a) is an explanatory diagram showing a magnetic field orientation apparatus for carrying out the method of manufacturing a magnetic recording medium of the present invention. In the same figure,
The magnetic disk 1 is rotated by a spindle 6 at a predetermined speed. A swing plate 4a is provided at an arbitrary distance from one magnetic coating surface of the magnetic disk 1. This swing plate 4a is moved by a motor 5a.
The magnetic pole 2a is formed to be swingable, as shown in FIGS. 1(a) and 1(b).

It is equipped with 3a. Similarly, a swinging plate 4b is provided on the other magnetic coating surface of the magnetic disk 1, and the swinging plate 4b swings by the motor 5b.
b, 3b.

FIG. 2(a) is a time chart showing an example of the swinging state of the swinging plates 4a, 4b. In FIG. 2(a), the vertical axis θ indicates a swing angle centered on point 7 shown in FIG. 2(b). As shown in FIG. 2(a), the swing angle 0 is maximum at the start of swing, gradually attenuates as time t passes, and reaches a constant value after time t1 (for example, 0=0).
converges to. after that.

Time t! when the swing angle θ is constant. until
A magnetic field is applied to complete the orientation.

Next, the operation of the above embodiment will be explained in more detail. Magnetic paint with magnetic powder evenly dispersed is coated on a substrate by rotation to a constant film thickness. after that.

While the magnetic coating film on the substrate is not dry, the magnetic disk 1 is rotated at a constant speed of 10 to 500 rpm by the spindle 6. In this state, magnetic poles 2a, 3a and 2b, 3b are placed at a distance of 0.5 to 4 m from the magnetic coating surface of the magnetic disk 1.
is oscillated according to the time chart shown in FIG. 2(a). The magnetic poles 2a, 3a and 2b.

3b is tilted with respect to the rotation center 8 of the magnetic disk 1 at the start of magnetic field application, as shown for the magnetic pole 2a in FIG. 2(b). Moreover, the magnetic pole 2a,
2b is set to N pole, and magnetic poles 3a and 3b are set to st and ii.

The above-mentioned swing angle O is initially set to ±5 to 45 degrees.

The time is 20 to 180 seconds, and θ=0 during this time.

Moreover, the rocking period is 1 to 20 times/second. In the state of O=0, the magnetic field orientation is continued for a time t2, and the time is 15 to 180 seconds. And this time,
During this time, the magnetic coating film is dried, and the magnetic field orientation is completed.

In the above embodiment, the magnetic poles 2a, 2b, 3a, and 3b are oscillated around a point 7 that is different from the rotation center 8 of the magnetic disk 1, but any method may be used as long as the magnetic pole angle can be changed arbitrarily. It's obvious.

As is clear from the above description, according to this example, the magnetic powder in the magnetic coating is shaken greatly at the beginning, and then
As the oscillation converges and the directionality is gradually unified, the media are arranged uniformly in the circumferential direction of the media substrate. Therefore, the squareness ratio is improved, and a uniform and smooth magnetic coating film can be formed.

[Effect of chewing]

According to the present invention, it is possible to provide a magnetic recording medium in which the magnetic powder in the magnetic coating film is made uniform in a direction horizontal to the surface of the magnetic coating film, and the squareness ratio is improved. That is, according to the present invention,
Since the magnetic powder in the magnetic coating film can be efficiently oriented in the circumferential direction of the magnetic disk, the centerline average roughness R is lower than that of magnetic disks manufactured using conventional orientation methods.
It becomes possible to improve a by about 20%, and the squareness ratio can be increased to 0.9 or more.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are explanatory diagrams showing a magnetic field orientation apparatus for carrying out the method of manufacturing a magnetic recording medium of the present invention, and FIG.
a) is a time chart showing an example of the swinging state of the swinging plate in the magnetic field orientation device shown in FIG. 1(a);
Figure (b) is an explanatory diagram showing the state of swinging of the magnetic poles. 1...Magnetic disk, 2a, 2b, 3a, 3b
...magnetic pole. 4a, 4b... rocking plate, 5a, 5b...
Motor, 6... spindle.

Claims (1)

[Claims] 1. Before the magnetic coating film applied to the rotating substrate dries, a magnetic field is applied to the surface of the magnetic coating film in the vertical and horizontal directions or in either direction to orient the magnetic powder in the magnetic coating film. A method for manufacturing a magnetic recording medium having a stroke, characterized in that the magnetic field is vibrated in a direction parallel to the surface of the magnetic coating film.