JPS60145529A - Manufacture of magnetic recording medium - Google Patents

Abstract

PURPOSE:To manufacture easily with good mass-producing property a disk- shaped magnetic recording medium orieinted in a circumferential shape by using a pair of oriented magnet strings formed by aligning a unit magnet having a specified dimension determined by a relation to the disk-shaped magnetic recording medium to be manufactured. CONSTITUTION:A pair of oriented magnet trains 1, 2 have a magnetic pole of a width (d) which is larger than a diameter of a disk-shaped magnetic recording medium to be manufactured, respectively, and they are placed at an interval (g) so that the S pole of a constituent unit magnet 1a and the S pole of 2a, the N pole of 1b and the N pole of 2b, and the S pole of 1c and the S pole of 2c- are opposed to each other, respectively. A non-magnetic supporting material sheet (raw material sheet) 3 to which a magnetic paint made by dispersing a ferromagnetic material powder into a binder vehicle is applied is inserted between the magnet strings 1 and 2, made to pass through in the direction as indicated with an arrow 4, and an orientation of the magnetic material powder in the magnetic paint is executed. Subsequently, it is punched so that the center of the disk comes onto the line of the magnetic sheet corresponding to the surface to to which the S pole and the N pole of the oriented magnet string contact.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a disc-shaped magnetic recording medium suitable for high-density recording.

In recent years, IIF flexible disc-shaped magnetic recording media have been widely used, such as flexible disks as mass storage devices for computers and magnetic sheets for methyl video cameras.

However, in this type of magnetic recording medium, the magnetic head slides along the circumference to read and write the recorded information, whereas in the magnetic recording medium of Tsunaka+hJ++', the magnetic layer is Since the formed FA magnetic powder is not oriented in a circumferential manner, the squareness ratio is poor, and the residual magnetization is smaller than that of a magnetic tape in which magnetic powder is oriented. Therefore, in this disk-shaped magnetic recording medium, it is necessary to widen the track width in order to obtain a sufficient output, which is an obstacle to achieving a high fP:l&.

In addition, when sword-shaped magnetic powder is used, town porcelain + can be obtained without using an orientation device during the coating and drying process. Since the sheet is mechanically oriented in the coating direction (e.g. lengthwise direction), even if a signal with a constant amplitude is recorded circumferentially in a circularly punched state, residual magnetization due to orientation will occur. Because the force in the longitudinal direction is large, the envelope waveform is not constant,
Another drawback was that the output fluctuated periodically.

Except for the drawbacks mentioned below, examples of circumferentially oriented magnetic recording media include hard disks obtained by spin coating. However, in the case of spin coating, after the support is formed into a disk shape, each recording medium is coated one by one, which has the disadvantage of poor mass productivity and high cost.

An object of the present invention is to provide a method for easily manufacturing a circumferentially oriented disk-shaped magnetic recording medium with good mass productivity by eliminating the drawbacks of the prior art described above. That is.

According to the research of the present inventors, by using a pair of oriented magnet arrays in which unit magnets having claw-like dimensions determined by the relationship with the disc-shaped magnetic recording medium to be manufactured are used, 1. ” was found to be achieved. The method for manufacturing a disc-shaped magnetic recording medium of the present invention is based on such knowledge, and more specifically, a pair of orientation magnet rows is prepared, and each orientation magnet row corresponds to a disc-shaped magnetic recording medium to be manufactured. A plurality of magnetic poles having a magnetic pole width larger than the diameter of the magnetic recording medium are connected to adjacent i'15. () The magnetic poles are arranged in the width direction of the magnetic poles so that the S pole and NM change to cross IL between "I magnet A", and the pair of oriented magnet rows are mutually configured. lil magnetic potential N pole and N
The poles, S poles, and S poles are arranged with a gap so that they are oriented in four directions, and ferromagnetic and magnetic powder is dispersed in a binder vehicle between the pairs of oriented magnetic columns. A non-magnetic support sheet coated with a magnetic paint made of the above-mentioned materials is arranged, and the distance from the pair of orientation magnet rows is kept almost constant, and the sheet is passed through the sheet in a direction substantially perpendicular to the direction in which the magnets are arranged in the orientation magnet row. Further, from the thus formed magnetic sheet having the oriented magnetic layer, punch out a disk so that the center of the disk is aligned with the line of the magnetic sheet I, which corresponds to the contact surface of the S and N poles of the oriented magnet array. There are 44 signs.

Hereinafter, typical aspects of the method for manufacturing a magnetic recording medium according to the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a schematic perspective view showing the phase arrangement of the magnetic sort material and the orientation magnetic material J in the embodiment of the present invention.

With reference to FIG.
Arrange it like 5<. These oriented magnetic columns l and 2 are as follows:
A plurality of intermediate magnetic poles each having a magnetic pole having a width d wider than the target diameter of the disc-shaped magnetic recording medium to be manufactured.
, le・ss, and 2a, ? b, 2c◆@fists are placed adjacent to each other, and these adjacent unit magnetic units are arranged in the direction of the width d of the magnetic poles so that the S and N poles alternate between them. In addition, these pair of orientation magnet arrays 1 and 2 each constitute a medium magnet F la (7) S pole, an S pole of 2a, an N pole of 1b, an N pole of 2b (7), and an S pole of 1c. and 20 S
The poles φΦ are arranged at a distance g such that they face each other. For example, the unit magnets 1a-s, 2aa*, and 2aa* are water magnets such as alnico, ferrite, rare earth cobalt, etc. with 6 magnets in the NS direction as shown in the figure.
is used.

In such a -pair orientation (d1, between the stone rows l and 2, one support is applied to the non-wire coated with a magnetic paint made by dispersing ferromagnetic powder in a binder vehicle), 'J body sheet ( Insert original fabric sheet) 3. Then, the original fabric sheet 3 is moved in a direction almost perpendicular to the direction in which the magnets are arranged (arrows in the drawing) while maintaining a position approximately at the center of the magnet spacing g, that is, at approximately equal intervals between the inner magnet rows 1 and 2. 4), and
The magnetic powder in the iG paint is oriented. At this time, the magnet spacing g is set so that a magnetic field approximately 1 to 5 times the coercive force of the magnetic powder used is applied, although it varies depending on the viscosity of the magnetic paint and the coating speed.

After the orientation, the orientation of the obtained magnetic layer is fixed by solidifying the magnetic layer by heat evaporation or heat curing as soon as possible.

FIG. 2 is a schematic diagram of the magnetization pattern of the magnetic layer thus oriented. 11 shows the alignment of the magnets on the do-face side of the oriented magnetic flux array 1, and the raw sheet runs in the direction of arrow 4 in the figure. When the magnetization is applied, a magnetization pattern like an arrow is formed in the magnetic layer of the original fabric sheet 13. Next, the magnet oriented in this way ('1 layer IJ:f anti-shi)' is placed directly on the F side of Fig. 2 (as shown by the dotted circle of ¥2r (2r<d)). A disc-shaped magnetic recording medium is punched out (1. ) By locating and omitting the magnetic layer L, a disc-shaped magnetic recording medium according to the present invention having a circumferentially oriented magnetic layer can be obtained.

Below, sword-shaped metal magnetic powder (Fe-Co-Ni alloy,
Long axis 0.25gm, axial ratio 8, Hc 14500e) 10
0 part, 25 parts of binder (a 6 part 4 mixture of vinyl chloride-vinyl acetate-vinyl alcohol copolymer and polyurethane elastomer), 1 part lecithin (dispersant), α-
Alumina (abrasive, particle size 0.4 m) 10 parts and 24
0 parts of solvent (methyl ethyl quinone and 1 part of toluene)
Magnetic paint made by dispersing and mixing with 1' BL compound) was applied to a dry thickness of 3 gm. The magnetic properties of the disc-shaped magnetic recording medium (diameter 47 mm) are summarized in the following table together with those of the conventional disc-shaped magnetic recording medium that was prepared in the same way except that the orientation treatment was not performed. For orientation, a unit magnet with a magnetic pole width of 50 mm was used, and a magnetic field of 50 (100 e) was applied.
llll :lj,' is relative speed + a 6 , 6 m
/S (7) Under the conditions, 1j was obtained using a Sengust head for recording and a ferrite head for 1st raw.

−j(− ) Kimoto: Relative value of conventional output OdB.

As can be seen from the results shown in Table 2, according to the method of the present invention, a pair of unit magnets arranged in a specific orientation in relation to the disc-shaped magnetic recording medium to be manufactured can be By using a magnet array, it becomes possible to manufacture a circumferentially oriented disc-shaped magnetic recording medium easily and with high productivity.

[Brief explanation of the drawing]

FIG. 1 shows a magnetic sheet I in a 1 m embodiment of the present invention.
FIG. 2 is a schematic perspective view showing the phase IL arrangement of the original fabric and the orientation magnet, and FIG. 2 is a schematic diagram of the magnetization pattern of the magnetic layer subjected to the orientation treatment. ■, 2@...Oriented magnet array ia, lb, l C,, esLjli Position magnet Ico 2a, 2b, 2C,, e*e11th position magnet 3.13
... Original fabric sheet 4 coated with (magnetic coating wood)... Original fabric sheet I, running direction J - d... Magnetic pole width of fist Cli magnet 2r... Diameter of disc-shaped magnetic recording medium (2nd section d ) g... Spacing between magnet rows

Claims (1)

[Claims] A pair of alignment magnet arrays is defined as a pair of alignment magnet arrays, each of which is composed of a plurality of unit magnets each having a magnetic pole width larger than the diameter of the disc-shaped magnetic recording medium to be manufactured. are arranged in the width direction of the magnetic poles so that S poles and N poles alternate between adjacent unit magnets; '' are arranged with a gap between them so that the N poles and the S poles face each other, and ferromagnetic powder is dispersed in a binder vehicle between the rows of oriented magnets with the - gradient. Apply magnetic paint made by tik 71j
A non-magnetic support sheet is arranged, and the distance from the pair of oriented magnetic strands is kept almost constant, and the oriented magnetic strands are passed in a direction substantially perpendicular to the arrangement direction of the oriented magnetic strands in the oriented magnetic strands. Further, the magnetic sheet having the oriented magnetic layer thus formed is punched out so that the center of the disk is on the line of the magnetic sheet I, which corresponds to the contact surface of the S and N poles of the oriented magnet array. A method of manufacturing a disc-shaped magnetic recording medium.