JPS62285226A - Surface lubricating method for magnetic disk medium - Google Patents

Abstract

PURPOSE:To form a thin-layered and uniform lubricating film with good reproducibility by overcoating a high boiling point inert liquid on a surface, then overcoating a lubricating agent contg. the high boiling point inert liquid as a solvent thereon, rotating the medium again at a high speed and forming the lubricating film on the surface thereof. CONSTITUTION:After the surface of the magnetic disk medium 1 under the rotation at a low speed is wiped with a dust-free cloth impregnated with the low boiling point fluorine base inert liquid, the medium 1 is rotated at a high speed so that the fluorine base inert liquid is thoroughly evaporated by the high-speed rotation and the dust and org. matter sticking to the surface of the medium 1 are removed with high efficiency. The rotation of the medium 1 is then returned to the low-speed rotation and the high boiling point fluorine base inert liquid which is the solvent for the lubricating agent is overcoated on the surface thereof; thereafter, the medium is rotated again at the high speed to form the extremely thin-layered high boiling point fluorine base inert liquid film (several-severaltens+Angstrom ) on the surface of the medium 1. Finally, the rotation of the medium is returned to the low-speed rotation and the lubricating agent soln. 8 contg. the high boiling point fluorine base inert liquid as the solvent is overcoated thereon. The medium is then rotated at a high speed and the thin-layered lubricating film is formed thereon.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] 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 with a magnetic film formed on a rigid substrate such as aluminum, a magnetic head is floated over a high-speed rotating disk medium to a minute gap using a floating RAD slider, which is a dynamic pressure gas axis. Recording/playback is being performed.

If the flying clearance of the magnetic head is reduced due to disturbances such as the incorporation of dust, vibrations of mechanical components such as a positioner, and the magnetic disk medium, the magnetic head and the magnetic disk medium will come into intermittently contact at high speed.

In addition, in recent years, so-called contact start-stop (C3S) type magnetic disk drives have become mainstream, in which the rotation of the disk medium is started and stopped while the magnetic head remains stationary on the magnetic disk medium. When the rotation is below a certain level, the gap between the magnetic heads does not reach the desired value, so the head and the medium come into contact with each other.

In this case, the magnetic film of the magnetic disk medium itself has lubricity, or even if it does, the lubricity is extremely low, so if contact running for a long time occurs, the magnetic head or the magnetic film of the magnetic disk medium will wear out, causing so-called A head crash occurs.

Therefore, by applying lubricant to the surface of the magnetic disk medium,
It is practiced to impregnate a lubricant into the medium to improve its lubricity.

However, if a large amount of lubricant is used, the coefficient of friction between the head and the disk medium increases, and the magnetic field attracts the magnetic field to the medium, damaging both. Therefore, it is necessary to use an appropriate amount of lubricant to overcoat the surface of the disk medium without increasing the coefficient of friction.

In addition, if the lubricant film thickness is uneven, the contact running at the time of starting and stopping the rotation will become unstable, which will also cause damage to both, so the lubricant film must be formed uniformly, and plating or sputtering should be avoided. For media in which a very thin magnetic film is formed on a smooth continuous thin film medium using a method such as several to several tens of layers,
In particular, its uniform formation is important.

Methods for forming the lubricant on the surface of the medium include 1) spin code method, 2) spray method, and 2) dipping method. Among these methods, the spin code method is widely used because it is simpler and suitable for mass production than other methods.

The apparatus used in the spin code method is shown in FIG. In the figure, an air disk medium 1 is mounted on a spindle 2, which is adapted to be rotated by a motor 3.

4 is a discharge nozzle disposed close to the surface of the medium 2;
The discharge nozzle 4 is attached to the discharge side of the pump 6 via a tube 5.

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

10 is a control device that controls opening and closing of the pump 6 and rotation of the spindle 2; 11.12 is the control device 10 and the motor 3;
and wiring that connects the control device 10 and the pump 6, respectively.

In the conventional spin code method, first, the magnetic disk medium 1
is attached to the spindle 2 and rotated at low speed (several tens to hundreds of rpm), and a lubricant solution 8 of a certain concentration is dripped onto it from the nozzle 4 until the surface of the medium is completely covered with the lubricant solution 8. Overcoat until wet, then spindle 2
was rotated at high speed (several thousand rpm), and its centrifugal force was used to shake off excess lubricant solution 8 and form a thin lubricant film on the surface of the magnetic disk medium.

However, with this method, there is a risk that the lubricant may be applied to the surface of the magnetic disk medium with dust or organic matter still attached to it, and the adhesion and uniformity of the lubricant film tend to deteriorate.

Therefore, as a method to remove attached dust and organic matter,
Attempts have been made to perform ultrasonic cleaning with an organic solvent before attaching the media to the spindle, and to wipe the media with a dust-free cloth impregnated with fluorinated inert liquid or alcohol after attaching the media to the spindle.

However, since these fluorine-based inert liquids and alcohols remain on the media surface, dust and organic matter cannot be completely removed, and there are problems such as changes in the lubricant concentration, and the lubricant formed on the media surface There was a drawback that there were large in-plane variations in film thickness and large variations between media.

[Purpose of the invention]

The present invention has been made in view of the problems of the prior art described above, and its purpose is to provide a surface lubrication method for magnetic disk media that makes it possible to form a thin and uniform lubricant film with good reproducibility. It is in.

[Structure of the invention]

To this end, the surface lubrication method for magnetic disk media of the present invention involves wiping the surface of a magnetic disk medium rotating at low speed with a dust-free cloth impregnated with a low boiling point inert liquid, and then rotating the medium at high speed once. After that, the rotation speed is returned to low speed, the surface is overcoated with a high boiling point inert liquid, and after high speed rotation is performed again, the rotation speed is returned to low speed, and the surface is further coated with lubrication using a high boiling point inert liquid as a solvent. overcoat the agent and again,
It was rotated at high speed to form a lubricating film on its surface.

〔Example〕

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

Figure 2 is a time chart that clearly expresses the features of the present invention. In this figure, the horizontal axis is time, the vertical axis is the rotational speed of the spindle (magnetic disk medium), and the symbol "***" is for 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 “888” indicates an overcoat of a lubricant solution using a high boiling point fluorine-based inert liquid as a solvent.

First, the surface of a magnetic disk medium rotating at a low speed is wiped using a dust-free cloth impregnated with a low boiling point fluorine-based inert liquid, and then 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 matter adhering to the medium surface are removed with high efficiency. .

Next, the medium is returned to low speed rotation, its surface is overcoated with a high boiling point fluorine-based inert liquid that is a lubricant solvent, and then high speed rotation is again performed. Here, since the fluorinated inert liquid used has a high boiling point, it does not completely evaporate even at high speed rotation, leaving an extremely thin layer (several to several dozen) on the surface of the medium. A liquid film forms.

Finally, the medium is returned to low speed rotation and its surface is overcoated with a lubricant solution in a high-boiling fluorinated inert liquid as a solvent, and then rotated at high speed to form a thin layer of lubricant on the surface. . Here, since an extremely thin layer of fluorine-based inert liquid is formed on the medium in the previous step, the affinity of the lubricant solution to the medium is extremely good, and the overcoating of the lubricant is performed satisfactorily.

Figures 3 and 4 show N1- using SiO□ as a protective film.
The film Tγ distribution of the lubricant film on the surface of the medium obtained by applying this example to a Co-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% perfluorofurkyl ether was used as the lubricant.

Table 1 Note that the dotted lines in FIGS. 3 and 4 are based on the conventional method and are drawn for comparison with this experimental example. As is clear from both figures, it can be seen that the in-plane uniformity (radial and angular directions) of the lubricant film thickness obtained in this experimental example is high.

Although perfluoroether was used as the lubricant in this experimental example, it is not limited to this, but 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 progeny-grade fatty acids and higher fatty acid metal salts can also be applied.

〔Effect of the invention〕

From the above, according to the lubrication method of the present invention, a thin lubricating film 1γ can be uniformly formed on the surface of a magnetic disk medium with good reproducibility, which lowers the coefficient of friction between the head and the medium, resulting in stable running of the head and medium. As a result, the durability and reliability of the magnetic disk device can be improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a spin coater used in carrying out the present invention, FIG. 2 is a time chart of the lubrication method of the present invention, and FIG.
FIG. 4 is a characteristic diagram of the distribution of the lubricant film according to the present invention and the conventional lubrication method. ■...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) Wipe the surface of a magnetic disk medium that is rotating at a low speed with a dust-free cloth impregnated with a low-boiling-point inert liquid, rotate the medium at a high speed, then return it to low speed rotation, and then After overcoating with an inert liquid with a boiling point and rotating at high speed again, returning to low speed rotation, further overcoating the surface with a lubricant using an inert liquid with a high boiling point as a solvent,
A method for lubricating the surface of a magnetic disk medium, which is characterized by forming a lubricating film on the surface of the medium by rotating it again at high speed. (2) The surface lubrication method according to claim 1, wherein the inert liquid is a fluorine-based inert liquid.