JPH01204217A - Device for orienting perpendicular magnetic recording medium - Google Patents

Abstract

PURPOSE:To orient a coated film in the perpendicular direction to it and to obtain high orientability by providing such a magnetic field generator which radially generates magnetic lines of force and a track on which a base body coated with a coating compd. contg. magnetic powder progresses spirally. CONSTITUTION:The magnetic coating compd. is prepd. by compounding the coating compd. contg. the magnetic powder and dispersing said compd. by a ball mill. This coating compd. is blade-coated on a polyester film and thereafter, the film is passed in an orienting deice. Namely, the base body 1 on which the magnetic coating compd. is coated winds around a nonmagnetic revolving roll 2 and passes the inside of the magnetic field generated by a superconducting magnet 5 and a high magnetic permeability core 3 while rotating spirally. The base body is dried in the perpendicularly oriented state by a hot wind dryer 6 placed near the outlet thereof. The magnetic recording medium is thereby continuously and perpendicularly oriented uniformly at a high degree of orientation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for orienting high-density perpendicular magnetic recording media such as floppy disks, digital audio tapes, and video tapes.

Conventional technology In recent years, with the increase in the density and capacity of magnetic recording media, it has become increasingly difficult to improve the recording speed with methods that use magnetization in the in-plane longitudinal direction of the recording medium due to the inherent barrier of self-demagnetization. It is becoming. Therefore, instead of this, methods using magnetization perpendicular to the surface of the recording medium have been actively developed.

Perpendicular magnetic recording media include those formed with a Go-Cr sputter film, etc., and those formed with a coating film containing magnetic powder, but from the point of view of economy and mass production,
Greater demand is expected for the latter.

When manufacturing a coating-type perpendicular magnetic recording medium, the magnetic powder is vertically oriented by some method during the process of applying a paint containing magnetic powder onto a substrate and after the application and before drying. Since this perpendicular orientation is advantageous, macrogonal ferrite magnetic powder is often used which is formed on a flat plate and has an axis of easy magnetization perpendicular to the plane of the plate. As a specific orientation method, a method has been devised such as passing through a magnetic field created by several sets of magnets with opposite poles facing each other with narrow intervals (for example, Japanese Patent Laid-Open No. 57-58244, etc.) ).

Problems to be Solved by the Invention However, magnetic recording media using the above-mentioned alignment method have not yet achieved sufficient perpendicular alignment. A method is needed.

In view of the above points, the present invention provides perpendicular magnetic recording that can achieve high orientation by placing an undried coating film containing magnetic powder in a strong magnetic field for a relatively long time until drying. A method for manufacturing a medium is provided.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a magnetic field generating device in which lines of magnetic force are radial, and a substrate coated with a paint containing an iridescent powder in a spiral shape. By providing a traveling trajectory, the coating film is orientated in the vertical direction.

Function The present invention makes it possible to vertically orient a magnetic recording medium continuously and evenly with a high degree of orientation by combining the orientation device with the above-described configuration with the current roll coating method, blade coating method, etc., which are excellent in mass production. possible.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

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 to a polyester film having a thickness of 75 .mu.m with a blade so that the dry thickness was approximately 2 .mu.m, and then passed through an orientation apparatus shown in FIG.

FIG. 1 shows a concave side view of an apparatus in which a substrate coated with magnetic paint is vertically aligned by passing in a spiral manner through a magnetic field having inward radial lines of magnetic force. Here, the magnetic shielding material 4 and the superconducting magnet 5 represent their respective cross sections. Further, the solid arrow indicates the direction of movement of the base.

(Leaves below) Table 1 The substrate 1 coated with magnetic paint is wound around a non-magnetic rotating roll 2, passes through the magnetic field created by the superconducting magnet 5 and the high permeability core 3 while rotating in a spiral pattern, and reaches its exit. It is dried in a vertically oriented state by a hot air dryer 6 placed nearby. The magnetic shielding material 4 is provided to prevent the magnetic field of the orientation device from leaking to the coating device side.

FIG. 2 is a cross-sectional view of the orientation device shown in FIG. 1, viewed from directly above.
The chain arrows in the figure indicate that the direction of the magnetic lines of force is inwardly radial.

After the coating process on one side is completed, the other side of the substrate is coated, oriented and dried in the same manner as above, and the coating film is cured at 60°C for about 24 hours, after which the mold is cut out and a magnetic floppy disk is prepared. was created.

The strength of the magnetic field is approximately 2 Gauss (G) on the orbit of the base.
ausS) (Comparative Example 1) As in the example, the magnetic paint having the composition shown in Table 1 was dispersed in a ball mill for about 72 hours, and then spread onto a 75 μm thick polyester film with a dry thickness of about 2 μm. It was applied so that Thereafter, it was passed through a magnetic field of approximately 2 kGauss generated by a flat-plate facing magnet as shown in FIG. FIG. 3 is a cross-sectional view of an orientation device using magnets with flat plates facing each other, viewed from the side.

The solid arrow indicates the direction of movement of the base, and the chain arrow indicates the direction of the lines of magnetic force.

While the substrate l coated with the magnetic paint is sent out in the direction of the arrow by the guide roll 12, it is oriented vertically by the magnetic field created by the magnets 11 and 11' with opposite poles, and is dried by the hot air dryer 6. be done.

After completing the coating process on one side, the other side of the substrate was coated, oriented and dried in the same way, and then cured at 60°C for about 24 hours in the same way as in the example, and then cut out and magnetically coated. I made a floppy disk.

<Comparative Example 2> Similar to Comparative Example 1, after dispersing and applying the magnetic paint having the composition shown in Table 1, it was dried without performing any special magnetic field orientation treatment as in Examples and Comparative Example 1, and The other side was also coated and dried in the same manner. Thereafter, hardening and die cutting were performed in the same manner as in Comparative Example 1 to produce a magnetic floppy disk.

Table 2 shows the measurement results of the output and P value (residual magnetic flux density in the vertical direction/residual magnetic flux density in the in-plane direction) of the magnetic floppy disks obtained in the above Examples and Comparative Examples 1 and 2. As is clear from this, it was recognized that the example had excellent characteristics in both output and P value.

Table 2 Effects of the Invention As shown above, the perpendicular magnetic recording medium obtained by the alignment apparatus of the present invention has excellent perpendicular alignment and can secure high output. Therefore, the present invention is extremely important in producing a high-capacity perpendicular magnetic recording medium.

[Brief explanation of the drawing]

Fig. 1 is a front view of the orientation device for a perpendicular magnetic recording medium of the present invention, Fig. 2 is a sectional view of the same device as Fig. 1 viewed from directly above, and Fig. 3 is a conventional example in which flat magnets are opposed to each other. FIG. 3 is a front view of the orientation device. 1... Substrate coated with magnetic paint, 2...
・Non-magnetic rotating roll, 3... High 131 IF ratio core, 4... Magnetic shielding material, 5...
Superconducting magnet, 6... Warm air dryer. Agent's name: Patent attorney Toshio Nakagawa 1 person Bar E & Satoru right l Coating method 2 bases - 1 non-magical rotary call 3 - Eitsu] 1 umbrella core 4 - Shagaku sea i7 piece material 5 - Taoj groove No. 2 6---fj1 genus R characteristics Fig. 1

Claims (2)

[Claims] (1) It is characterized by being equipped with an orienting magnetic field generating device that generates a magnetic field such that magnetic lines of force become radial, and a means for moving an undried base coated with a paint containing magnetic powder into the magnetic field in a spiral manner. Orientation device for perpendicular magnetic recording media. (2) The orienting device for a perpendicular magnetic recording medium according to claim (1), wherein the orienting magnetic field generating device is constituted by a superconducting magnet.