JPS62285227A - Apparatus for producing magnetic disk medium - Google Patents

Abstract

PURPOSE:To form a thin-layered and uniform lubricating film by continuing stopping the drop of a lubricating soln. by a ball which closes a flow passage in a discharge nozzle at all times and dropping the lubricating soln. when the supplied lubricating soln. attains a prescribed pressure or above. CONSTITUTION:The ball 15 is formed of a carbon fluoride plastic material such as 'Teflon(R)' and is held lifted upward by a coil spring 16 at all times to close the flow port 14a in the upper part of an expanding part 14. The ball is pushed down by overcoming the pressing force of the coil spring 16 to open the flow port 14a when the pressure of the lubricating material soln. on a tube 5 side increases. The thin-layered lubricating film is thereby uniformly formed on the surface of a magnetic disk medium with the good reproducibility of the film thickness; therefore, the coefft. of friction between a head and medium is decreased and the stable running property of the head and medium is improved. As a result, the durability and reliability of the magnetic disk device are improved.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a manufacturing technology for magnetic disk media, and in particular to a method for forming a thin and uniform lubricant film on the surface of a magnetic disk medium. This relates to manufacturing equipment for.

[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 floating head slider, which is a dynamic pressure gas axis, is used to levitate the magnetic head over a high-speed rotating disk medium over a minute gap. Recording/playback is in progress.

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, magnetic disk drives of the so-called contact start/stop (CC8) method have become mainstream, in which the rotation of the disk medium is started and stopped while the magnetic head remains stationary above the magnetic disk medium. When the rotation of the magnetic head is below a certain level, the gap between the magnetic head does not reach the desired value, and the head and the medium come into contact with each other.

Contact between the head and the medium occurs under various conditions as described above, but the magnetic film of the magnetic disk medium itself has lubricating properties.
Or, even if it does have it, it has extremely low lubricity, so if long-term contact running occurs, the magnetic film of the magnetic head or magnetic disk medium will wear out, resulting in a so-called head crash.

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, when a large amount of lubricant is used, the coefficient of friction between the head and the disk medium increases, causing the head to stick to the medium and 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 rotation will become unstable, which will also cause damage to both, so the lubricant film must be formed uniformly, and it is necessary to use plating or sputtering methods. Uniform formation is particularly important for media in which a magnetic film is formed very thinly, from several to several tens of layers, on a smooth, continuous thin film medium.

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 more flexible than other methods.

The apparatus used in the spin code method is shown in FIG. In the diagram, a magnetic disk medium l is attached to a spindle 2, and the spindle 2 is 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.

FIG. 5 is an enlarged cross-sectional view of the discharge nozzle 4, which has a tapered dripping port 41 in the lower part, and a filter 42 in the internal flow path for removing dust contained in the lubricant solution. is installed.

Forming a lubricating film using the above-mentioned apparatus is usually performed as follows. First, the magnetic disk medium 1 is attached to the spindle 2 and rotated at low speed (several tens to hundreds of rpm).
A lubricant solution 8 of a certain concentration is dripped onto this from the discharge nozzle 4, and the medium surface is overcoated until it is completely wetted with the lubricant solution 8.

Thereafter, the spindle 2 is rotated at high speed (several thousand rpm), and the centrifugal force is used to shake off the excess lubricant solution 8 and form a three-layer lubricant film on the surface of the magnetic disk medium.

However, in this case, (1) even after the pump 6 is closed and the lubricant discharge is stopped, the lubricant solution remaining in the discharge nozzle 4 and tube 5 intermittently leaks from the dripping port 41 onto the medium surface; (2) the discharge nozzle; The solvent of the lubricant solution remaining in 4 and tube 5 gradually evaporates, and the lubricant concentration changes, resulting in large variations in the thickness of the lubricant film formed on the surface of the disk medium and between media. There was a problem.

[Purpose of the invention]

The present invention has been made in view of the problems of the prior art described above, and its object is to provide a magnetic disk medium manufacturing apparatus that is capable of forming a thin and uniform lubricating film.

[Structure of the invention]

For this purpose, the magnetic disk medium manufacturing apparatus of the present invention includes:
a spindle that holds and rotates a magnetic disk medium;
A magnetic disk medium manufacturing apparatus comprising a discharge nozzle that drips a lubricant solution onto the magnetic disk medium, and a pump that supplies the lubricant solution to the discharge nozzle, a ball in the discharge nozzle and a ball that presses the ball. A spring is attached, and the ball normally closes the flow path in the discharge nozzle to stop the lubricant solution from dripping, and when the supplied lubricant solution reaches a predetermined pressure or higher, the ball moves against the spring. The lubricant solution is moved to open the flow path by moving against the pressing force of the lubricant solution.

〔Example〕

Embodiments of the magnetic disk medium manufacturing apparatus of the present invention will be described below. Note that the same reference numerals are used for the same parts as those in the conventional example described above.

FIG. 1 best represents the features of the present invention.

That is, FIG. 1 is a cross-sectional view of the discharge nozzle 13 of the manufacturing apparatus of the present invention, and the nozzle 13 is entirely formed in the shape of a vibrator from a corrosion-resistant metal such as stainless steel, and has an enlarged part 14 formed in its lower part. A ball 15 and a coil spring 1 are placed inside the enlarged portion 14.
6 is attached, and a drip opening 17 is formed at the lower end.

The ball 15 is molded from a fluorocarbon plastic material such as Teflon, and is normally pushed upward by a coil spring 16 to block the communication port 14a at the top of the enlarged portion 14, but the lubricant solution on the tube 5 side When the pressure increases, it is pushed down against the pressing force of the coil spring 16, and the flow port 14a
Open.

That is, if the pressure of the discharge pump 6 is P, the spring constant of the coil spring 16 is Δ, the compression length of the coil spring 16 is Δ, and the radius of the flow path is r, then if P>2ttr"・ΔL-, the ball 15 is pressed down by the pressure of the discharge pump 6, and the lubricant solution is discharged from the dripping port 17.

On the other hand, in the case of P<2π"2 ・ΔL-, the ball 15 is pushed up by the coil spring 16, and as a result, the ball 15 closes the flow port 14a, and the discharge of the lubricant solution stops instantaneously, and the discharge The solvent of the lubricant solution remaining on the nozzle 4 or tube 5 side will not leak, and the solvent of the lubricant solution 8 will not evaporate and its concentration will not change.

In addition, since the ball 15 is made of fluorocarbon plastic such as Teflon, which is chemically and thermally stable and has good affinity with the solvent of the lubricant solution, the lubricant solution does not denature and a homogeneous lubricant film is created. can be formed on the surface of the medium.

The solid line in FIG. 2 shows the film thickness distribution of an experimental example of a lubricant film formed using this apparatus on a magnetic disk medium plated with N1-Co-P using Sin as a protective film. Here, the solvent of the lubricant solution is Fluorinert, and the solvent is 0.05
% concentration of perfluoroalkyl ether was used.

Note that the dotted line in the figure is based on the conventional method and is drawn for comparison with this experimental example.

As is clear from the figure, it can be seen that the in-plane uniformity of the lubricant film thickness obtained in this experimental example is high.

FIG. 3 shows the relationship between lubricant film thickness and friction coefficient.

It can be seen that the friction coefficient gradually increases as the lubricant film thickness increases between the cores, and increases rapidly when the lubricant film thickness exceeds 20. In the conventional method shown in Figure 2, there are more than 20 disk rotation positions on the inner surface, so the coefficient of friction increases rapidly in this area, reducing stability when the head is in contact with the medium and causing a risk of head crash. It can be seen that the quality 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 higher fatty acids and higher fatty acid metal salts can also be applied.

〔Effect of the invention〕

As described above, according to the magnetic disk medium manufacturing apparatus of the present invention, a thin lubricant film can be uniformly formed on the surface of the magnetic disk medium with good reproducibility, so the coefficient of friction between the head and the medium is reduced, and the head/medium As a result, the durability and reliability of the magnetic disk device can be improved.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the discharge nozzle of the magnetic disk medium manufacturing apparatus of the present invention, Fig. 2 is a characteristic diagram of the lubricant film distribution according to the present invention and the conventional manufacturing apparatus, and Fig. 3 is the lubricant film thickness and friction coefficient. Figure 4 is a perspective view of the spin coater.
FIG. 5 is a sectional view of a discharge nozzle of a conventional magnetic disk medium manufacturing apparatus. 1...Magnetic disk, 2...Spindle, 3...
Motor, 4... Nozzle, 5... Tube, 6...
pump, 7... tube, 8... lubricant solution, 9.
...Tank, 10...Control device, 11.12...Wiring, 13...Discharge nozzle, 14...Enlarged part, 15
...Ball, 16...Coil spring, 17...Dripping port.

Claims (2)

[Claims] (1) Manufacturing a magnetic disk medium comprising a spindle that holds and rotates a magnetic disk medium, a discharge nozzle that drips a lubricant solution onto the magnetic disk medium, and a pump that supplies the lubricant solution to the discharge nozzle. In the apparatus, a ball and a spring that presses the ball are installed in the discharge nozzle, and the ball normally blocks the flow path in the discharge nozzle to stop the lubricant solution from dripping, and the lubricant solution is supplied. When the pressure reaches a predetermined pressure or higher, the ball moves against the pressing force of the spring to open the flow path and drip a lubricant solution. Device. (2) The apparatus for manufacturing a magnetic disk medium according to claim 1, wherein the balls are molded from fluorocarbon plastic.