JPS62180527A - Manufacture of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a high quality magnetic disk recording medium having specified capability stably and in a short time by changing process of controlling the film thickness uniformly independently from other processes in rotational frequency, time etc. CONSTITUTION:A motor M1 is started, and rotational frequency of a substrate 3 is raised, and supply of magnetic coating to the substrate face is started by a nozzle 5 when the rotational frequency arrived at about 50-150 RPM at a point A. The magnetic coating supplied at constant speed rotation to a point B is diffused slowly and uniformly over the whole face of the substrate 3 by centrifugal force. After termination of supply of the coating at the point B, rotational frequency of the substrate 3 is raised to about 300-600 RPM, and excess coating is flung away by strong centrifugal force. At the same time, process to adjust viscosity of the coating on the substrate and to control film thickness of inner periphery and outer periphery is performed from a point C to a point D. Then, rotational frequency of the substrate 3 is raised to about 1,000-1,800 RPM, and a thin film is formed by strong centrifugal force between points E and F. Thus, a very thin uniform film is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a spin coating method for forming a magnetic recording film on a substrate surface of a recording medium such as a magnetic disk.

In the present invention, on the disk surface of a non-magnetic support such as aluminum,
A magnetic material such as Fe, 03, etc. was applied in a uniform thin film. It is applied to spin coating of magnetic films in recording media such as rigid disks.

[Background of the invention]

Conventionally, in spin coating of magnetic disks,
A magnetic film was formed on the disk by a low-speed rotation process for adhering magnetic paint to a non-magnetic support and a high-speed rotation process for removing excess paint from the adhered paint and forming a film.

However, as the density of magnetic disks increases, the materials, compositions, etc. of magnetic paints change, and the viscosity tends to decrease. For this reason - conventional spin coaches with low and high rotational speeds provide high density, high resolution, □
In order to obtain a magnetic disk having both high override and uniform high output and power, productivity was low. In other words, in Fig. 3, the vertical axis is the disk substrate rotational speed RPM, and the horizontal axis is the time SEC. If we show a conventional spin coding curve, the disk starts rotating at time O and continues at a low constant speed from point A to point 6. It is a rotation that supplies magnetic paint to the substrate from point A to point B, then blows away excess paint on the substrate from point B to point 6, and increases the viscosity of the paint on the substrate. was. Thereafter, the rotation was started from point 6 to point D, continued to point E, formed a magnetic film, and ended at point F.

With this conventional method, it takes a long time to obtain a magnetic disk that has the above-mentioned high density and high resolution, as well as a uniform high output.
6. Related technology of this type includes, for example, Japanese Patent Application Laid-Open No. 57-27439.

[Object of the Invention] The object of the present invention is to solve the above-mentioned problems and provide a method for efficiently mass-producing magnetic disks having high density, high resolution, and uniform high output at low cost. There is a particular thing.

[Summary of the invention]

The present invention relates to a method for obtaining a high-quality, high-density magnetic disk recording medium by alleviating the bottlenecks of the prior art as described above. A low-speed rotation process in which the magnetic paint is supplied to the substrate surface and the paint is uniformly adhered to the substrate surface, and then, at the same time, the excess paint on the substrate surface is shaken off, and the magnetic paint is applied to the substrate surface. A process is established to adjust the viscosity of the paint on the surface and control the film thickness uniformly on the inner and outer peripheries, and then a thin film is formed using strong centrifugal force due to high-speed rotation, which controls the film thickness uniformly. It is a spin coating method that produces a magnetic disk recording medium with a predetermined performance in a short time, in mass production, stably and with high quality by varying the process independently from other processes and the rotation speed per hour, etc. .

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. A disk substrate 3 made of aluminum or the like is fastened and fixed by a fastener 4 to a shaft 2 located at the center of a magnetic paint recovery chamber 1 and rotated by a variable speed motor M1, and then rotated by the motor M1.

Nozzles 5 for supplying magnetic paint are provided on both sides of the disk substrate 3, and the nozzles 5 are attached to the tip of an arm 7 that is supported by a drive shaft formed by M2.
First, the arm 7 is directed from the outer periphery to the inner periphery of the rotating substrate 3 as shown by the arrow in the figure, and a magnetic coating material is supplied to the rotating substrate 3 for spin coating. The spin coating process of the present invention using the above apparatus is shown in FIG. 4, with the vertical axis representing the disk substrate rotational speed RPM and the horizontal axis representing time SeG.

This will be explained using a curve representing the change in substrate rotation speed over time. First, at time O, motor M1 is started, and when the substrate rotation speed increases by 30 RPM and reaches approximately 50 to 150 RPM at point A, the nozzle 5 starts supplying magnetic paint to the substrate surface, and B The magnetic paint is supplied at a constant speed (50 to 150 RPM) to a certain point, and is spread slowly and evenly over the entire surface of the substrate 3 by centrifugal force. After the paint supply is finished at point B, the rotation speed of substrate 3 is approximately 300 to 600 RP.
From 6 points to D, raise the temperature to M and shake off excess paint using strong centrifugal force, while at the same time adjusting the viscosity of the paint on the substrate and controlling the film thickness on the inner and outer peripheries to be uniform.
Go to the point. After that, increase the rotation speed of substrate 3 to about 1000 to 1800 RPM between point E and point F.
Through the process of forming a thin film using strong centrifugal force, an extremely thin and uniform film can be obtained.

〔Effect of the invention〕

According to the spin coating method of the present invention, the process of adjusting the viscosity of the paint on the substrate surface and controlling the film thickness uniformly on the inner and outer peripheries has a different rotation speed and time from other processes. , the finished magnetic film is uniform and extremely thin,
This has the advantage that high-quality magnetic disks with high density and high resolution can be mass-produced in a short time and efficiently.

[Brief explanation of drawings]

FIG. 1 is a front view of an apparatus according to an embodiment of the present invention. FIG. 2 is a side sectional view, FIG. 3 is an explanatory diagram showing a conventional process, and FIG. 4 is an explanatory diagram showing a process according to an embodiment of the present invention. 1... Magnetic paint collection chamber, 2... Rotating shaft. 3...-disc substrate, 4... fastener, 5
... Nozzle, 6... Drive shaft, 7... Nozzle arm. 4th flash

Claims (1)

[Claims] 1. Hold and rotate the inner periphery of a non-magnetic support such as aluminum, apply magnetic paint on the non-magnetic support,
In the manufacturing process of magnetic recording media in which a magnetic recording layer is provided by applying orientation, etc., in the coating process, after the low-speed rotation process in which magnetic paint is supplied to the non-magnetic support and adhered, the excess on the non-magnetic support is removed. At the same time, the viscosity of the paint on the non-magnetic support is adjusted, and the film thickness on the inner and outer peripheries is uniformly controlled. 1. A method for manufacturing a magnetic recording medium, characterized in that in a method for forming a thin film, the step of controlling the film thickness uniformly and other steps, the rotation speed, time, etc. are independently varied.