JPS6063726A - Method and device for manufacturing magnetic disk medium - Google Patents

Abstract

PURPOSE:To improve the manufacturing efficiency of a magnetic disk medium, by producing a magnetic field which is uniformly distributed in the radial direction of a magnetic disk base plate in a direction which is parallel to the base plate and perpendicular to the radial direction and giving a magnetic field having no leaked magnetic flux to the base plate. CONSTITUTION:Magnetic fields whose lines of magnetic force produced in spaces a and a' and b and b' are oriented in opposite directions to each other in the circumferential direction of a magnetic disk base plate 3 as shown by the arrows in the figure, are constituted and the magnetic fields become ones which are uniformly distributed in the radial direction of the base plate 3 and parallel to the base plate 3. No magnetic field is produced to the applied surface of a magnetic paint of the base plate 3 except the spaces a, a' and b, b' and, especially, the magnetic field in the radial direction of the base plate 3 which damages the orienting property becomes almost zero. When the magnetic disk base plate 3 is rotated at a rotating speed of >=100rpm, a magnetic disk medium having an excellent orienting property can be obtained and, moreover, the paint is dried at a high speed and the working property is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a method for manufacturing a magnetic disk medium and an apparatus for manufacturing the same. One thing is the degree of orientation of the magnetic coating (
The present invention relates to a magnetic disk medium manufacturing method and a magnetic disk medium manufacturing apparatus that make it possible to improve the degree to which the axial directions of crystal grains of magnetic powder are aligned in the same direction.

(b) Prior Art and Problems A magnetic disk device is used as a storage device in a computer system, and the storage medium of the magnetic disk device is a magnetic disk. Magnetic disks are made by applying paint containing magnetic powder to a super-finished aluminum base using the spin code method, rotating the base in a magnetic field to dry the paint, and polishing the surface to make it smooth. ing. As the magnetic powder, γ-Fe2O3 is generally used.

The crystal grains of this magnetic powder are needle-shaped, and the long plane direction is called the axis of easy magnetization. When this magnetic powder is mixed with paint and applied to a magnetic disk substrate, the noise characteristics vary depending on the size of the crystal particles and the application process, and in order to improve the playback output of recorded signals, the magnetic field is removed before the paint dries and hardens. By adding this, we aim to improve the degree of orientation by aligning the axis of easy magnetization of the magnetic powder. In order to improve this degree of orientation, a magnetic field with no leakage magnetic flux in which the direction of the magnetic lines of force are aligned in the circumferential direction of the magnetic disk base, is parallel to the magnetic disk base, and is evenly distributed in the radial direction, and the direction of the magnetic force lines is oriented in the radial direction. It is necessary to give

Conventionally, it has not been possible to configure the magnetic field for improving the degree of orientation in a direction parallel to the magnetic disk base and perpendicular to the radial direction, that is, in the circumferential direction, and uniformly distributed in the radial direction. There was leakage magnetic flux. In this case, unless the magnetic disk substrate is rotated at a low speed of 50 revolutions per minute or less and the magnetic paint is dried slowly over a long period of time, a magnetic disk medium with a high degree of orientation and few defects such as pinholes can be obtained. I couldn't. Therefore, it takes a long time to dry the magnetic paint, which has the drawback of reducing the ability to manufacture magnetic disk media.

Furthermore, it has been difficult for conventional magnetic disk medium manufacturing apparatuses to construct a magnetic field free of leakage magnetic flux as described above.

(C) Object of the Invention The object of the present invention is to eliminate the above-mentioned drawbacks by generating a magnetic field that is parallel to the magnetic disk base and perpendicular to the radial direction, uniformly distributed in the radial direction, and without leakage magnetic flux. By using this manufacturing device, the magnetic disk substrate can be rotated at high speed, the magnetic paint can be dried quickly, and the magnetic disk media with good orientation and no defects can be produced. The purpose is to provide a manufacturing method that can be used.

(d) Structure and object of the invention According to the present invention, there is provided a method for manufacturing a magnetic disk medium, in which a magnetic disk medium is manufactured by coating a magnetic disk substrate with a paint containing magnetic powder by a spin code method and drying the coating. A magnetic field is formed in the circumferential direction of the magnetic disk base, parallel to the base, and uniformly distributed in the radial direction, and the magnetic disk base is rotated within the magnetic field at a rotation speed of 100 revolutions per minute or more to dry the paint. A magnetic disk medium manufacturing method comprising: a shaft to which a magnetic disk substrate is attached and rotated; and a magnetic field provided close to both surfaces of the magnetic disk substrate and perpendicular to the radial direction of the magnetic disk substrate. In a magnetic disk medium manufacturing apparatus equipped with a magnetic device that is capable of applying in a direction parallel to the magnetic disk substrate a width greater than a width that covers the coating film width of the magnetic disk substrate, the magnetic device is configured to apply Two air gaps parallel to the radial direction of the magnetic disk base and having different spacings are provided in each magnetic path constituting a closed magnetic path that is formed independently on both sides of the base, facing each other with the magnetic disk base in between, The direction of the magnetomotive force is aligned so that the poles facing each other across the magnetic disk base in each gap are the same, and the directions of the magnetic lines of force in each gap are opposite in the circumferential direction of the magnetic disk base. This is achieved by providing a magnetic disk medium manufacturing apparatus that does the following.

(e) Embodiment of the Invention FIGS. 1, 2, 3, and 4 are diagrams showing an example of a magnetic disk medium manufacturing apparatus of the present invention.

FIG. 1 is a configuration diagram of the magnetic disk medium manufacturing apparatus seen from above, FIG. 2 is a sectional view at the position indicated by A in FIG. 1, and FIG. 3 is a sectional view at the position indicated by B in FIG. 1. , FIG. 4 is a sectional view at the position indicated by C in FIG. 1. This embodiment shows a case where two permanent magnets are used as the magnetic field line generation source. 1st
This will be explained using FIG. 2, FIG. 3, and FIG. 4. The magnetic disk base 3 is attached to a rotating shaft 9 by a mounting tool 8 and rotates. The permanent magnet 1 is attached to the magnetic paths 2 and 6 by protrusions 2'' and 6'' provided on parts of the magnetic paths 2 and 6, which are made of high magnetic permeability material, and the permanent magnet 5 is made of high magnetic permeability material. Projecting portions 4'' and 7 provided on part of the magnetic paths 4 and 7 used
It is attached to the magnetic paths 4 and 7 by . The magnetic paths 2 and 6 each cover approximately half of the area of the magnetic disk substrate 3, thereby covering the entire surface of one side of the magnetic disk substrate 3, and occupying gaps at different intervals indicated by a and b in the magnetic disk substrate 3. Configured in parallel to the radial direction. In addition, the magnetic paths 4 and 7 each cover approximately half the area of the magnetic disk base 13, thereby covering the entire other surface of the magnetic disk base 3, and ao
The gaps at different intervals indicated by ``and b'' are formed on the magnetic disk substrate 3.
0 Magnetic path 2 across the magnetic disk base 3 parallel to the radial direction
and 6, respectively. The magnetic poles of the permanent magnets 1 and 5 are, for example, if the magnetic paths 6 and 7 sides are N poles, and the magnetic paths 2 and 4 sides are S poles. Therefore, the directions of the lines of magnetic force generated in the gaps a, ao and b and b' form magnetic fields that are oriented in opposite directions in the circumferential direction of the magnetic disk base 3, as shown by the arrows in FIG. This magnetic field is uniformly distributed in the radial direction of the magnetic disk base 3 and becomes a magnetic field parallel to the magnetic disk base qi3. And the void a,
At locations other than a+, S, and b', no magnetic field is generated against the magnetic coating surface of the magnetic disk substrate 3, and in particular, the magnetic field in the radial direction of the magnetic disk substrate IM3, which impairs orientation, is almost zero.

Further, the spacings between the gaps a, a' and the gaps S, b' are configured to be different from each other. If this interval is the same, the magnetic disk base 3
A shading pattern of magnetic powder appears in the radial direction. In this example, the number of air gaps is two, but it is possible to increase the number of air gaps by increasing the number of permanent magnets, but in this case, it is necessary to configure the structure so that the intervals between each air gap are not the same. It is.

If the magnetic disk base 3 is rotated at 100 revolutions per minute to 0 revolutions in the manufacturing apparatus shown in FIGS. It dries and improves workability. FIG. 5 is a diagram illustrating the relationship between the degree of orientation and the number of rotations of the magnetic disk substrate 3.

The magnetic powder has a coercive force of 350 oersted, and the strength of the magnetic field in the gaps a, a', and b' of the above manufacturing equipment is 200 oersted.
In the case of approximately 0 process steps, the orientation time is 15 degrees, and the degree of orientation is approximately constant, with the half-width ΔH being the smallest at around 200 to 1000 rotations, as shown by the curve.

(f) As described in detail, the present invention is capable of drying paint containing magnetic powder by rotating the magnetic disk base at high speed, so the drying speed of the paint is extremely fast and the orientation is Since a magnetic disk medium with good quality can be obtained, the manufacturing efficiency of magnetic disk media can be improved.

[Brief explanation of the drawing]

1, 2, 3, and 4 are diagrams showing an example of the magnetic disk medium manufacturing apparatus of the present invention, and FIG. 5 is a diagram illustrating the relationship between the degree of orientation and the rotation speed of the magnetic disk substrate. It is. 1.5 is a permanent magnet, 2.2'', 4.4°, 6.6'. 7.7'' is a magnetic path, 3 is a magnetic disk base, 8 is a mounting tool, and 9 is a rotating shaft. Illustration 1 Lesson U Illustration 4 Illustration

Claims (1)

[Scope of Claims] 1) A magnetic disk medium manufacturing method in which a magnetic disk medium is manufactured by applying a paint containing magnetic powder to a magnetic disk substrate by a spin code method and drying the coating, the method comprising: forming a magnetic field parallel to the base and uniformly distributed in the radial direction, and rotating the magnetic disk base within the magnetic field at a rotation speed of 1,00 revolutions per minute or more;
A method for manufacturing a magnetic disk medium, comprising drying the paint. 2) It is provided close to the surface of both the shaft on which the magnetic disk base is attached and rotated and the magnetic disk base, and applies a magnetic field perpendicular to the radial direction of the magnetic disk base in a direction parallel to the magnetic disk base. In a magnetic disk medium manufacturing apparatus equipped with a magnetic device capable of applying an electric current to a width greater than the width of the coating film of a magnetic disk substrate, the magnetic device is a closed magnetic device formed independently on both sides of the magnetic disk substrate. In each magnetic path constituting the path, two gaps parallel to the radial direction of the magnetic disk base and having different spacings are provided facing each other with the magnetic disk base in between, and each gap is provided with the magnetic disk base being sandwiched between the two gaps. A magnetic disk medium manufacturing apparatus characterized in that the direction of the magnetomotive force is aligned so that the opposing poles are the same, and the directions of the lines of magnetic force in each gap are opposite in the circumferential direction of the magnetic disk substrate.