JPH01263940A - Manufacture of perpendicular magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a perpendicular recording medium fit for a high recording density at high orientation by making a magnetic band, which is obtained with magnetizing a coating medium in a perpendicular direction, co-travel in the same direction after the coating of the medium. CONSTITUTION:When a magnetic coating 2 for the perpendicular recording medium coated on a non-magnetic substrate 1 moves in an arrow direction, it is controlled at the same speed as the nonmagnetic substrate 1 by a motor shaft 4, it is magnetic-field-oriented while moving by a magnetic band magnetized in the perpendicular direction for a band surface, and simultaneously, the orientation is fixed by a hot blast generator 6. Here, the magnetic band is a resin series magnet kneaded with magnetic powder, etc., and a magnetic flux density on a non-magnetic substrate surface is set at 1,000 gauss. Thus, by making the magnetic band for the orientation co-travel with the medium, its surface performance and orientation can be drastically enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to the manufacture of magnetic recording media, and in particular,
The present invention relates to a method of manufacturing coated perpendicular recording media such as tapes and floppy disks.

BACKGROUND OF THE INVENTION In recent years, with the development of magnetic recording, recording density has been increasing. In order to cope with higher density, magnetic recording media have been developed with higher coercive force and higher magnetic flux density. Recently, the recording method itself has changed from the conventional longitudinal magnetic recording method to the perpendicular magnetic recording method, which allows for higher density recording, and high-quality magnetic recording media suitable for the perpendicular magnetic recording method are being developed. desired.

The magnetic powder used in the coated media used in this perpendicular magnetic recording method has a hexagonal plate shape, unlike the acicular magnetic powder used in conventional longitudinal recording media, and the axis of easy magnetization is in the thickness direction. It's like having a

Therefore, when performing surface formation after coating on the substrate,
The magnetic powder has the characteristic that the axis of easy magnetization tends to be oriented perpendicular to the coating film.

However, since sufficient vertical alignment cannot be obtained only by alignment during surface formation, vertical alignment is achieved by magnetic field alignment using fixed magnets with opposite poles (for example, Japanese Patent Application Laid-Open No. 57-58244 Such).

Problems to be Solved by the Invention However, in the magnetic field orientation using the magnetic field orientation device as described above, after the magnetic material is oriented, it moves in a direction that cuts the lines of magnetic force, so the magnetic material receives a force in the in-plane direction of the coating film. However, the problem was that agglomeration and surface roughness were likely to occur, and the properties could not be sufficiently improved by orientation.

In view of the above problems, the present invention provides a method for manufacturing a perpendicular magnetic recording medium with excellent orientation.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention is characterized in that after the coating medium is applied, a magnetic band that is suspended in a direction perpendicular to the medium is caused to run alongside the medium at the same speed and in the same direction. A method for manufacturing a perpendicular recording medium is provided.

As a result of their research, the inventors found that the effect of perpendicular recording media is greater when the media is oriented while being held stationary in a static magnetic field after being coated, compared to when the media is oriented without being moved in a static magnetic field. It was found that the surface properties and orientation were greatly improved. and,
When orienting a perpendicular recording medium after coating, it is equivalent to aligning a magnetic band perpendicular to the medium by running it parallel to the medium at the same speed and in the same direction, keeping it stationary in a static magnetic field. It has been found that it is possible to obtain surface properties and orientation of This means that by running a magnetic band for orientation alongside the medium, it is possible to create the same state as when oriented by a static magnetic field, which is extremely useful when producing perpendicular recording media continuously. Useful.

EXAMPLE Hereinafter, an example of the method for manufacturing a perpendicular magnetic recording medium of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of an example of an orientation device using the present invention, viewed from the side. When a magnetic paint 2 for a perpendicular recording medium coated on a non-magnetic substrate 1 moves in the direction of the arrow, the motor It has a structure in which the magnetic band 3 is controlled to have the same speed as the non-magnetic substrate 1 by a shaft 4, and is oriented in a magnetic field while moving by a magnetic band 3 magnetized in a direction perpendicular to the band surface, and at the same time, the orientation is fixed by a hot air generator 6. The magnetic band here is a resin magnet kneaded with magnetic powder or the like, and the magnetic flux density on the surface of the nonmagnetic substrate is 1000 Gauss. This magnetic band is a flexible magnet and may be of any type as long as it has a magnetic flux density of 1000 Gauss or more on the surface of the nonmagnetic substrate.

(Example 1) A magnetic paint having the composition shown in Table 1 was prepared and dispersed in a ball mill for about 72 hours to produce a magnetic paint.

This was applied with a blade to a polyester film with a thickness of 14 μm so that the dry thickness was approximately 4 μm, and then passed through a magnetic field orientation device shown in Figure 1, dried, surface treated, and kept at 60°C overnight. It was cured to produce a magnetic tape.

Table 1 The frequency characteristics of the magnetic tape described above were measured using an amorphous head with a gap width of 0.2 μm and a rectangular wave. Table 2 shows the value of (linear recording density at a frequency where the output is half the output value at low frequency) and the squareness ratio in the vertical direction, which is one of the magnetic properties.

Table 2 (Example 2) Using the same paint as in Example 1 and using the same orientation device as in Example 1,
A tape was produced without using a hot air generator, and the same measurements as in Example 1 were performed.

(Comparative Example) As in the example, a magnetic paint having the composition shown in Table 1 was dispersed in a ball mill for about 72 hours, and then applied to a 14 μm thick polyester film to a dry thickness of about 4 μm. Thereafter, it was passed through a magnetic field of approximately 1,500 Gauss generated by a flat-plate facing magnet as shown in FIG. FIG. 2 is a cross-sectional view of an orientation device using flat-plate facing type magnets, viewed from the side.

The substrate 1 coated with the magnetic paint is oriented in the vertical direction by the magnetic field created by the magnets 7 and 7'' having opposite poles while traveling in the direction of the arrow, and is dried by the hot air dryer 6.

After drying, the surface was treated and cured into a tape in the same manner as in Example 1.
The frequency characteristics and magnetic characteristics were measured.

As is clear from Table 2, the present invention makes it possible to create a perpendicular recording medium with high recording density and high orientation.

In addition to the effects of the invention, the present invention achieves perpendicular recording suitable for high recording density with high orientation by causing a magnetic band that remains perpendicular to the medium to run in the same direction as the medium after coating the medium. It is used to create a medium and is extremely useful for raising seedlings.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a manufacturing apparatus for a perpendicular magnetic recording medium according to the present invention, and FIG. 2 is a cross-sectional view of an orientation device using flat-plate facing type magnets, viewed from the side. 1...Nonmagnetic substrate, 2...Magnetic paint,
3...Magnetic band, 4...Motor shaft, 5
...Pulley, 6...Hot air generator, 7
．． 7°・・・・・・Orienting magnet.

Claims (3)

[Claims] (1) A method for producing a magnetic recording medium in which a magnetic paint in which hexagonal ferrite magnetic powder is dispersed in a binder is applied onto a non-magnetic substrate and dried, the method comprising: after applying the magnetic paint;
1. A method for manufacturing a perpendicular magnetic recording medium, comprising making a magnetic band suspended in a direction perpendicular to the medium run in the same direction as the medium. (2) The method for manufacturing a perpendicular recording medium according to claim (1), characterized in that the demagnetized magnetic band runs parallel to the back side of the coated surface of the medium. (3) The method for manufacturing a perpendicular magnetic recording medium according to claim (1) or claim (2), characterized in that hot air is sent to the surface of the coating film while running alongside the magnetic band.