JPS5958632A - Production for coating vertical magnetic recording medium - Google Patents

Abstract

PURPOSE:To attain a high-density recording magnetic disc which is suitable for digital recording even with respect to film thickness, by providing plural vertical magnetic field generators in parallel or in multistage, and inserting coating magnetic mediums painted to substrates between magnetic poles, and hardening them and applying a vertical magnetic field to them. CONSTITUTION:A magnetic paint including a binding resin and a magnetic powder is applied to a substrate 1 such as an Al disc or the like to form a magnetic coating film 2, these substrates (three substrates in an example) are placed on fixing tables 30 between magnetic poles in an electric furnace 14 provided with permanent magnets 20 in flour stages vertically, and the magnetic powder (having a high reluctant force Hc) is orientated vertically while hardening the magnetic coating film 2 by a heater 13. Thus, high-density recording is possible even in a digital recording disc of a thickness used in a magnetic rotary sensor, and the reproduced output, the S/N, etc. are improved. It is a matter of course that the output is improved in comparison with the conventional output in an ordinary magnetic disc. Electromagnets may be used instead of permanent magnets 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for producing a magnetic recording medium, particularly a valley-coated perpendicular magnetic recording medium that is capable of recording, reproducing, and erasing high-density magnetic recording in digital recording. It is.

[Prior art]

Conventionally, the standard of performance in general magnetic recording is the amount of recorded information per unit area, that is, the recording density. In order to increase this recording density, it has been believed from both experiments and theory that a medium with a high coercive force HC and a thin film thickness is required. This is based on the idea that the phenomenon of magnetic recording is used only to more effectively incorporate the random component magnetization and longitudinal component magnetization of the medium, that is, the in-plane magnetization mode.

Incidentally, magnetic recording media, mainly for digital recording, manufactured based on this concept have various drawbacks. For example, when this type of magnetic recording medium is attached to a measurement magnetic rotation sensor that rotates at 1,000 to io, o o o PM, the axial direction will change due to the load (thrust load) applied to the shaft. For example, the thrust load is 5 and 4.
In the case of 10 kg, the displacement is 102 m and 204 m, respectively. Therefore, when designing this type of device, the amount of displacement is taken into full consideration, and technically the detection closed magnetic head is provided in the scrap with a gap of 80 to 100 μm. Naturally, this is accompanied by a decrease in the reciprocating output, so the film thickness is increased in order to improve the output. Increasing the film thickness causes a decrease in recording density. Therefore, increasing Hc, for example 10
Paint film Jun 50-1 using magnetic powder of 00-20000e
00 μm is being considered, but as a result, there are various problems such as resolution, reproduction output, SN ratio, noise, and surface roughness.

Furthermore, even in the case of ordinary magnetic disks, there is a limit to increasing the density, and higher density is desired.

[Purpose of the invention]

The purpose of the present invention is to eliminate the above-mentioned drawbacks by
Another object of the present invention is to provide a method for manufacturing a coated perpendicular magnetic recording medium that enables high-density recording suitable for digital recording even if the film is thick.

[Summary of the invention]

The present invention arranges a plurality of magnetic poles on a staircase or in parallel,
The method is characterized in that a perpendicular magnetic field is applied to the coated magnetic medium applied to the substrate to completely cure the coated magnetic medium.

Hereinafter, the configuration and effects of the present invention will be explained in more detail with reference to FIGS. 1, 2, 3, and 4 based on the drawings and specific examples.

FIG. 1 shows a schematic cross-sectional view for explaining the operation of a magnetic rotation sensor and a magnetic head (multi-head magnetoresistive element) according to an embodiment of the present invention. 1 is a disk substrate, 2 is a magnetic coating film, and 3 is a magnetic head, which is attached to a support stand 4, and the support stand 4 is fixed to the outer box of a motor 5, and the disk substrate 1 is fixed to a shaft 6 that rotates the motor. .

Further, arrows 7 and 8 indicate the direction, and the coating film 2 and the magnetic head 3 are designed in consideration of sufficient displacement against the load in the direction of the arrow during operation.
There is a gap of 80 to 100 μm. Further, the rotation speed is variously selected from 1,000 to 10.00 ORPM depending on the purpose.

FIG. 2 is a schematic cross-sectional view showing the configuration of a magnetic rotation sensor manufactured according to the present invention. That is, (8) is a magnetic coating film in which magnetic powder having magnetic anisotropy is vertically arranged on the disk substrate 1. [F]) is a magnetic rotation sensor in which a sputtered permalloy film 9 having high magnetic permeability is formed on a disk substrate 1, and magnetic M2 is further arranged perpendicularly to the film surface on the permalloy film. It is a schematic sectional view.

FIG. 3 is a schematic cross-sectional view showing a manufacturing apparatus using permanent magnets used in the present invention. That is, the disk substrate 1 coated with the magnetic film 2 by the spin coating method is placed on the fixing table 30 and further placed in the container 10, and several stages of permanent magnets are formed so as to form a perpendicular magnetic field. It is inserted between 20.

The whole is placed on the support jig 11, and then the heater 1
3 is fixed to an electric furnace 14 through a supporting and fixing table 12. This heater cures the magnetic coating at once.

FIG. 4 is a schematic cross-sectional view showing a manufacturing apparatus using an electromagnet used in the present invention. That is, it is a system in which electromagnets are arranged in several stages, 100 is a magnetic core, 101 is a coil, and each coil is wound around the magnetic core. In addition, in order to apply an effective perpendicular magnetic field to the ends of the magnetic core, magnetic poles 102 are placed on each side.
are provided, and are stacked in several stages as in FIG. In addition, in order to reduce the leakage magnetic field to the outside, auxiliary magnetic cores 103 are respectively installed, and a magnetically closed circuit is formed. Also, the polarity of the magnetic poles at that time should be as shown in the figure. That is, it is performed in the direction of the current flowing through the coil, and the strength of the perpendicular magnetic field depends on the magnitude of the current.

Hereinafter, the present invention will be described in detail based on Examples.

[Embodiments of the invention]

Example 1 Polyvinyl butyral powder 70 g1 Magnetic powder 700
A paint for a magnetic rotation sensor consisting of 120 g of fluorine oil and cyclohexanone was applied to an aluminum disk (thickness: 1.5 cm, 34 wφ), the surface of which had been previously cleaned.
) to a film thickness of 8 μm, and using the apparatus shown in FIG. 3 or 4, the film was vertically magnetized and cured at 120C for 30 minutes.

The surface roughness of the disk immediately after curing was ⇠a = 0.162 μm, which was much better than the conventional disk Ra = 0.328 μm. Conventional disks required surface processing, but the processing of the magnetic disk for magnetic rotation sensors according to the present invention was poor.

The electrical characteristics of the disk manufactured by the above process were measured. As a result, compared to the conventional disk, the output was improved by about 25% in the structure shown in FIG. 2 according to the present invention, and 35% in the structure shown in FIG. Note that the number of defects was also reduced to 115 in each case.

In addition, a magnetic disk with a film thickness of about 1 μm was manufactured in the same manner using a common magnetic disk paint, and very good results were obtained in this case as well.

〔Effect of the invention〕

The effect from the perspective of magnetic properties, which is one of the factors contributing to the properties of the present invention, is compared with the conventional perpendicular component magnetic properties: (1) The perpendicular orientation ratio Br of the present invention compared to unoriented 67
% and HC improved by 68%.

(2) The vertical orientation ratio of the present invention relative to the in-plane orientation was improved by 10% at 13r and by 77% at HC.

In both cases, the properties were better than conventional non-oriented and in-plane oriented.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams for explaining the present invention, Figure 3,
FIG. 4 is a schematic sectional view of the manufacturing apparatus used in the present invention. DESCRIPTION OF SYMBOLS 1...Disk substrate, 2...Magnetic film, 3...Magnetic head (multi-head magnetoresistive element), 4...Support stand, 5...Motor, 6...Shaft, 9...・High magnetic permeability film (sputtered permalloy film) 10... container, 1
DESCRIPTION OF SYMBOLS 1... Support stand, 12... Support fixing stand, 13... Heater, 14... Electric furnace, 20... Permanent magnet, 30
...Fixed base, 100...Magnetic core, 101...Coil, 102...Magnetic pole, 103Continued from page 10 Inventor Tsunehiro Matsui 3300 Hayano, Mosho-shi, Hitachi, Ltd. Mobara Factory 0 Inventor Kazuo Shirahashi Inventor Katsuyoshi Tamura Inside Mobara Factory, Hitachi, Ltd., 3300 Hayano, Mobara City Inventor Satoshi Takahashi Inside Hitachi Device Engineering Co., Ltd. 2, 3350 Hayano, Mobara City

Claims (1)

[Claims] A coated perpendicular magnetic recording medium characterized in that a substrate having a coated magnetic recording medium film is inserted into a gap in a closed magnetic circuit formed by perpendicular magnetic field generators arranged in parallel or in a multistage manner, and then cured. manufacturing method.