JPH0664732B2 - Surface lubrication method for magnetic disk media - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a surface lubrication method for uniformly forming a thin lubricating film on the surface of a magnetic disk medium.

[Prior art]

In a magnetic disk device that uses a magnetic disk medium in which a magnetic film is formed on a rigid substrate such as aluminum, a floating head slider that is a dynamic pressure gas axis is used to fly the magnetic head to a minute gap on a disk medium that rotates at high speed. Recording / playback.

Here, when the floating clearance of the magnetic head is reduced due to disturbance such as mixing of dust, vibration of the mechanical components such as a positioner, and the magnetic disk medium, the magnetic head and the magnetic disk medium are intermittently contacted at high speed.

Further, in recent years, a so-called contact start stop (CSS) type magnetic disk device that starts and stops the rotation of the disk medium while the magnetic head is stationary on the magnetic disk medium has become mainstream. When the rotation is less than a certain value, the clearance of the magnetic head does not reach the desired value, so that contact travel between the head and the medium occurs.

In this case, the magnetic film itself of the magnetic disk medium does not have lubricity, or even if it does have extremely low lubricity, the magnetic head or the magnetic film of the magnetic disk medium wears out when contact travel occurs for a long time, So-called head crash occurs.

Therefore, apply a lubricant to the surface of the magnetic disk medium,
BACKGROUND ART A medium is impregnated with a lubricant to improve its lubricity.

However, if a large amount of lubricant is used, the coefficient of friction between the head and the disk medium becomes large, and the magnetic head sticks to the medium, damaging both. Therefore, it is necessary to use an appropriate amount of the lubricant that overcoats the surface of the disk medium within a range that does not increase the friction coefficient.

In addition, if the lubricant film thickness is not uniform, contact travel at the time of rotation start / stop becomes unstable, and this also damages the two. For a medium in which a magnetic film is formed very thin with several to several tens of liters on a smooth continuous thin film medium by the method,
In particular, its uniform formation is important.

As a method for forming the lubricant on the surface of the medium, there are a spin coat method, a spray method, a dip method and the like. Among them, the spin coating method is widely used because it is simpler than other methods and suitable for mass production.

The apparatus used in the spin coating method is shown in FIG. In the figure, a magnetic disk medium 1 is attached to a spindle 2, and the spindle 2 is rotated by a motor 3.

Reference numeral 4 denotes a discharge nozzle arranged near the surface of the medium 2.
The discharge nozzle 4 is attached to the discharge side of a pump 6 via a tube 5.

The suction side of the pump 6 is connected via a tube 7 to a tank 9 for storing a lubricant solution 8, which sucks the lubricant solution 8 and discharges it from the nozzle 4.

Reference numeral 10 is a control device for controlling the opening / closing of the pump 6 and rotation of the spindle 2, and 11 and 12 are wirings for connecting the control device 10 and the motor 3 and the control device 10 and the pump 6, respectively.

In the conventional spin coating method, first, the magnetic disk medium 1
Is attached to the spindle 2 and is rotated at a low speed (several tens to several hundreds rpm), and a lubricant solution 8 having a constant concentration is dropped from the nozzle 4 so that the surface of the medium is completely filled with the lubricant solution 8.
Overcoat until wet, and then rotate the spindle 2 at high speed (several thousand rpm) to shake off excess lubricant solution 8 by its centrifugal force to form a thin lubricant film on the surface of the magnetic disk medium. I was doing.

However, according to this method, the lubricant may be applied while the dust and the organic matter are attached to the surface of the magnetic disk medium, and the adhesion and uniformity of the lubricating film are likely to be deteriorated.

Therefore, as a method of removing dust and organic matter that has adhered, ultrasonically clean with an organic solvent before attaching the medium to the spindle, after attaching the medium to the spindle, use a dust-free cloth impregnated with a fluorine-based inert liquid or alcohol. Wipe.
Etc. have been tried.

However, since these fluorine-based inert liquids and alcohols remain on the medium surface, dust and organic substances cannot be completely removed, and there are problems such as changes in the lubricant concentration, and the lubrication formed on the medium surface. There is a drawback that there are large variations in the film thickness within the plane and among the respective media.

[Object of the Invention]

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a surface lubrication method for a magnetic disk medium capable of forming a uniform lubricating film in a thin layer with good reproducibility. It is in.

[Structure of Invention]

To this end, the surface lubrication method of the magnetic disk medium of the present invention involves wiping the surface of the magnetic disk medium rotating at a low speed with a dust-free cloth impregnated with an inert liquid having a low boiling point, and temporarily rotating the medium at a high speed. After that, return to low speed rotation, overcoat the surface with an inert liquid with a high boiling point, rotate again at high speed, then return to low speed rotation, and further lubricate the surface with an inert liquid with a high boiling point as a solvent. The agent was overcoated and rotated again at high speed to form a lubricating film on the surface.

〔Example〕

Examples of the surface lubrication method for the magnetic disk medium of the present invention will be described below.

FIG. 2 is a time chart showing the features of the present invention well, in which the horizontal axis represents time, the vertical axis represents the rotational speed of the spindle (magnetic disk medium), and the symbol “***” represents low boiling point fluorine. Wipe with a dust-free cloth impregnated with an inert liquid,
“↓↓↓” indicates an overcoat of a high boiling point fluorine-based inert liquid, and “” indicates an overcoat of a lubricant solution using a high boiling point fluorine-based inert liquid as a solvent.

First, after wiping the surface of a magnetic disk medium rotating at a low speed with a dust-free cloth impregnated with a low boiling point fluorine-based inert liquid, the medium is rotated at a high speed. Since the fluorine-based inert liquid used here has a low boiling point, the fluorine-based inert liquid is completely evaporated by high-speed rotation, and dust and organic substances adhering to the medium surface are removed with high efficiency. .

Next, the medium is returned to the low speed rotation, the surface thereof is overcoated with a high boiling point fluorine-based inert liquid which is a solvent of the lubricant, and then the high speed rotation is performed again. Here, since the fluorine-based inert liquid has a high boiling point, it does not completely evaporate even at high speed, and a very thin layer (several to several tens of liters) of a high-boiling fluorine-based inert liquid is formed on the medium surface. A film is formed.

Finally, the medium is returned to low speed rotation, the surface thereof is overcoated with a lubricant solution using a high boiling point fluorine-based inert liquid as a solvent, and then rotated at high speed to form a thin lubricating film on the surface. . Here, since the ultrathin layer of the fluorine-based inert liquid is formed on the medium in the previous step, the affinity of the lubricant solution for the medium is extremely improved, and the lubricant is overcoated favorably.

3 and 4 show Ni-Co- using SiO ₂ as a protective film.
The thickness distribution of the lubricant film on the medium surface obtained by applying this example to a P-plated magnetic disk medium is shown. The characteristics of the low boiling point fluorine-based inert liquid and the high boiling point fluorine-based inert liquid used in the experiment are shown in Table 1 below, and 0.05% of perfluoroalkyl ether was used as the lubricant.

The dotted lines in FIGS. 3 and 4 are based on the conventional method and are shown for comparison with the present embodiment. As can be seen from both figures, the in-plane uniformity of the lubricating film thickness (radius and angular direction) obtained in this example is high.

Although perfluoroether was used as the lubricant in this experimental example, it is not limited to this, and liquid fluorocarbon, solid fluorocarbon, a mixture of liquid fluorocarbon and solid fluorocarbon, Various lubricants such as higher fatty acids, higher fatty acid metal salts, and mixtures of higher fatty acids and higher fatty acid metal salts are also applicable.

〔The invention's effect〕

As described above, according to the lubrication method of the present invention, a thin lubricating film thickness can be formed on the surface of the magnetic disk medium with good reproducibility, so that the coefficient of friction between the head and the medium becomes low, and the stable running property of the head and the medium is achieved. As a result, the durability and reliability of the magnetic disk device can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a spin coater used for carrying out the present invention, FIG. 2 is a time chart of the lubrication method of the present invention, and FIG.
FIG. 4 and FIG. 4 are characteristic diagrams of the distribution of the lubricating film according to the present invention and the conventional lubrication method. 1 ... Magnetic disk, 2 ... Spindle, 3 ... Motor, 4 ... Discharge nozzle, 5 ... Tube, 6 ... Pump, 7 ... Tube, 8 ... Lubricant solution, 9 ... Lubricant Solution storage container, 10 ... control device, 11, 12 ... wiring.

Claims (2)

[Claims] 1. A surface of a magnetic disk medium rotating at a low speed is wiped with a dust-free cloth impregnated with an inert liquid having a low boiling point, the medium is once rotated at a high speed and then returned to a low speed rotation, and the surface thereof is rotated. After overcoating the high boiling inert liquid and rotating it again at high speed, return to low speed rotation, and then overcoat the surface with a lubricant using the high boiling inert liquid as a solvent and rotate it again at high speed. A surface lubrication method for a magnetic disk medium, which comprises forming a lubrication film on the surface thereof. 2. The surface lubrication method according to claim 1, wherein the inert liquid is a fluorine-based inert liquid.