JPH0711862B2 - Method for coating magnetic film on magnetic disk - Google Patents

Description

The present invention relates to a method for coating a magnetic film on a magnetic disk, and more particularly to a method for coating a magnetic film on a magnetic disk suitable for obtaining a uniform film thickness.

[Prior Art] Japanese Patent Application Laid-Open No. 57-27439 and Japanese Patent Application Laid-Open No. 6-27439
As disclosed in Japanese Unexamined Patent Publication No. 0-89824, it is known to control the number of revolutions of a magnetic disk substrate and the standing time after coating to control the film thickness to a desired film thickness.

[Problems to be Solved by the Invention] In the above-mentioned conventional technique, the temperature of the magnetic disk substrate is not taken into consideration, and the occurrence of film thickness defects in the manufactured magnetic disk increases as the magnetic film becomes thinner. However, there is a problem that productivity is reduced.

The present invention has been made in view of the above-mentioned problems of the prior art, and provides a magnetic film coating method for a magnetic disk, which can improve the accuracy of the magnetic film coating thickness and improve the productivity of the magnetic disk. With the goal.

[Means for Solving the Problems] The magnetic film coating method for a magnetic disk according to the present invention is applied to a magnetic film coating method for a magnetic disk in which a coating material for forming a magnetic film is coated on a rotating magnetic disk substrate. In particular, the coating of the magnetic disk substrate is characterized in that the temperature of the magnetic disk substrate is controlled while the temperature of the spindle for rotating the magnetic disk substrate and the temperature of the atmosphere of the magnetic disk substrate are controlled to constant values.

[Operation] According to the present invention, the magnetic disk substrate is controlled to a constant value by the temperature of the spindle that rotates the substrate and the ambient temperature of the substrate. Therefore, when the temperature of the magnetic disk substrate is high, the viscosity of the applied paint is high, and when the temperature of the magnetic disk substrate is low, the viscosity of the applied paint is low. Therefore, the shake-off state and the diffusion state of the paint due to the rotation of the magnetic disk substrate slightly change depending on the temperature of the magnetic disk substrate, and a significant difference occurs in the film thickness. Therefore, by controlling the temperature of the magnetic disk substrate to be constant, the viscosity of the paint on the magnetic disk substrate becomes constant, and there is no variation in the film thickness between magnetic disk substrates,
It is possible to mass-produce magnetic disks having a uniform film thickness.

EXAMPLES The present invention will be described in more detail with reference to the examples shown in the accompanying drawings.

FIG. 1 is an explanatory view showing an embodiment of the present invention. First
As shown in the figure, an aluminum substrate 1 for a magnetic disk is held by a spindle 2. The spindle 2 receives the rotational driving force of the motor 3 via the belt 4 and is rotatably formed. The chamber 5 promotes the paint scattered from the outer periphery of the aluminum substrate 1 as the aluminum substrate 1 rotates. On both sides of the aluminum substrate 1, a slur 6 for applying paint is arranged, and a hydraulic cylinder (not shown) is used as a drive source so as to be movable in the radial direction of the aluminum substrate 1 as shown by an arrow. Further, in order to control the temperature of the aluminum substrate 1, an air supply unit 7 is arranged on the upper part, and temperature-controlled air is constantly supplied to control the ambient temperature of the aluminum substrate 1. The air supply unit 7 may be provided inside the chamber 5. The temperature of the spindle 2 is controlled by the friction torque of the spindle 2 itself. Here, the friction torque is a torque required to rotate the spindle 2 in a stopped state, and is a value empirically equivalent to heat generated by a ball bearing of the spindle 2 or the like. When the friction torque is increased, the temperature of the spindle 2 rises and the temperature of the aluminum substrate 1 can be controlled to a high value.

FIG. 2 is a diagram showing an example of the relationship between the coating thickness of the aluminum substrate 1 and the temperature of the aluminum substrate 1 obtained in the embodiment shown in FIG. According to this, the coating film thickness is 0.025 μm / deg.
Changes at a rate of.

FIG. 3 shows the relationship between the friction torque of the spindle 2 and the temperature of the aluminum substrate 1. As is clear from FIG. 3, the temperature of the aluminum substrate 1 changes at a rate of 0.03 deg / gcm.

As a method of controlling the temperature of the spindle 2, for example, a method of circulating temperature-controlled water or oil inside the spindle 2, or a method of blowing temperature-controlled air or water outside the spindle 2 may be used. .

EFFECTS OF THE INVENTION According to the present invention, the coating film thickness can be controlled stably, and the variation in film thickness between substrates can be reduced. Therefore, the film thickness accuracy can be improved and the magnetic disk productivity can be improved. Has the effect of

Further, the difference in the coating conditions such as the spindle speed and the coating time due to the difference in the coating device is reduced, and the adjustment of the coating device is facilitated.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the present invention, and FIG. 2 is a view showing a relationship between a coating thickness of an aluminum substrate 1 and a temperature of the aluminum substrate 1 manufactured by executing the embodiment shown in FIG. 3 is a diagram showing the relationship between the friction torque of the spindle shown in FIG. 1 and the temperature of the aluminum substrate. 1 ... Aluminum substrate, 2 ... Spindle, 3 ... Motor,
4 ... Belt, 5 ... Chamber, 6 ... Nozzle, 7 ...
… Air supply unit.

Claims (1)

[Claims] 1. A method for applying a magnetic film to a magnetic disk, wherein a paint for forming a magnetic film is applied on a rotating magnetic disk substrate, wherein the temperature of the magnetic disk substrate is the temperature of a spindle for rotating the magnetic disk substrate, and A method for applying a magnetic film on a magnetic disk, which comprises applying a paint while controlling the temperature of the atmosphere of the magnetic disk substrate to a constant value.