JPH05305563A - Polishing method and polishing device of magnetic disc - Google Patents

Abstract

PURPOSE:To uniformly enhance the surface smoothness of a magnetic disc, improve output stability in one bit unit, suppress polishing flaw, and improve track quality by leaps and bounds. CONSTITUTION:Two sets of air nozzles 6, 6a and polishing tapes 5, 5a wound on rollers 4, 4a and traveled are horizontally arranged to the surface of a magnetic disc 1. The form ratio of the injection holes 6b, 6c of the air nozzles and the range of air pressure are specified. Thus, the unbalanced component of the stress added to the magnetic disc at polishing is suppressed to improve the traveling state, whereby polishing flaw can be suppressed, surface smoothness can be more uniformly enhanced, and track quality can be improved by leaps and bounds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for polishing magnetic disks such as floppy disks and video floppy disks, and more particularly to a method and apparatus for polishing magnetic disks having a relatively thin base film.

[0002]

2. Description of the Related Art As a magnetic disk, a coating type is widely used in which a magnetic paint using an organic solvent is applied on a base film and the organic solvent is evaporated and dried at a high temperature.
It is required to have excellent electromagnetic conversion characteristics, durability, running performance, and truck quality.

On the other hand, with the recent trend toward higher density recording, the magnetic disk is becoming thinner, and the magnetic layer and the base film are becoming thinner. In addition, in order to achieve high output, metal magnetic powder and barium ferrite magnetic powder are used to increase the filling rate and further promote surface smoothing.
For this reason, the film strength of the magnetic layer is weakened, and polishing scratches tend to be more likely to occur during surface finishing as compared with the conventional one. In particular, it has become more difficult than ever to polish the surface of a magnetic disk having a relatively thin base film. Therefore, in a magnetic disk having a storage capacity of 10 MB or more, there is a strong demand for a disk having excellent output quality in units of 1 bit, no missing pulses, no bit error, and excellent track quality.

As a method of polishing a magnetic disk, a method of polishing the surface of the magnetic disk with a polishing tape is generally used, and various proposals have already been made as a method for improving the polishing property. For example, a method of arranging elastic rolls sandwiched by a polishing tape, driving and running the magnetic disk and the polishing tape in a predetermined direction, and rocking. In addition, a method in which both sides of a magnetic disk are sandwiched by flexible polishing sheets and a load is applied from above by a head or a solid block of the same shape to run the magnetic disk.
Further, various methods such as a method of polishing while pressing the polishing member and the magnetic disk with compressed air have been proposed. Such a proposal is disclosed in, for example, JP-A-60-151.
It is as disclosed in Japanese Patent Laid-Open No. 838, Japanese Patent Laid-Open No. 61-182751, Japanese Patent Laid-Open No. 61-136764, and the like.

[0005]

However, in the case of the above-mentioned proposal, not only the good aspects thereof are necessarily exhibited, but especially for a high-density magnetic disk of 10 MB or more, it is sufficient for the problems associated with the track quality. It has not improved yet.

For example, a method of arranging elastic rolls sandwiched by polishing tapes or a method of applying a load by a head or a solid block having the same shape is used for a track density in a low density magnetic disk of 2 MB or less. However, since the recording wavelength is short for a high density magnetic disk of 10 MB or more, if foreign matter, polishing powder, or dust in the air is trapped between the polishing member and the magnetic disk, the magnetic layer becomes fine. However, there is a problem in that the product yield is reduced due to adverse effects such as missing pulses.

The method of polishing while pressing the polishing member and the magnetic disk with compressed air is suitable for a relatively thick magnetic disk having a base film thickness of about 75 μm, but the base film thickness is 33. In a relatively thin magnetic disk having a thickness of about 62 μm, it is difficult to uniformly press the polishing member, so polishing unevenness is likely to occur, which cannot stabilize the output in 1-bit units. There was a risk of deterioration.

As described above, there are many problems that must be solved in order to obtain a high-density magnetic disk that ensures reliability without bit errors.

The present invention solves the above problems, uniformly improves the surface smoothness of the magnetic disk, improves the output stability in 1-bit units, and dramatically improves the track quality. And its device.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a polishing tape which is run by interposing an air nozzle and a roller for pressing the polishing tape and the surface of a magnetic disk. -2 sets of a groove and a groove are arranged horizontally with respect to the surface of the magnetic disk, and the ratio of the groove length to the groove width of the air nozzle is 15 or more and less than 60, and the pressure of the pressurized air- Is 0.
It is achieved by polishing the magnetic disk within the range of 02 MPa or more and less than 0.20 MPa.

[0011]

The present invention has the above-described structure, that is, two sets of the air nozzle for ejecting the pressurized air and the polishing tape for traveling while being interposed by the roller are arranged in the horizontal direction with respect to the surface of the magnetic disk. By doing so, the unbalanced component of the stress applied to the magnetic disk is suppressed and the stable running state is maintained. This has the effect of reducing the surface wobbling of the magnetic disk during polishing, and uniformly pressing the polishing tape and the surface of the magnetic disk. Further, both sides of the magnetic disk can be polished at the same time.

Further, by limiting the shape of the air nozzle ejection port and the range of air pressure, the polishing tape and the surface of the magnetic disk can be pressed more evenly, and they are scraped off during polishing. It has a function of appropriately blowing away the polishing powder, foreign particles attached to the polishing tape or the magnetic disk, or the like. Furthermore, since dust in the air is not attracted, it is possible to obtain a magnetic disk with less polishing scratches, which is effective in improving the product yield.

Further, the apparatus of the present invention can easily carry out the above-mentioned polishing method, and can easily support the magnetic disk, set the drive mechanism, and adjust the pressure of the air. Can be obtained at

As described above, according to the present invention, it is possible to uniformly improve the surface smoothness of the magnetic disk and dramatically improve the track quality.

[0015]

EXAMPLES Examples of the present invention will be specifically described below.

In order to improve the track quality of the magnetic disk, it is important to reduce the space loss with the head and stabilize it. For that purpose, it is necessary to remove fine projections existing on the surface of the magnetic layer by polishing to make it smooth, and especially when finishing the surface of a magnetic disk having a small recording wavelength or a high track density, It is important to improve the surface smoothness without causing fine scratches on the layer. Further, in a relatively thin magnetic disk having a base film thickness of about 33 to 62 μm, it is important to minimize the stress applied during polishing from the viewpoint of preventing bending. In order to obtain the optimum polishing state of the magnetic disk, the present inventors arranged two sets of air nozzles and polishing tapes in the horizontal direction with respect to the surface of the magnetic disk, and further, the shape of the air nozzles and the air nozzles. By limiting the range of pressure, it has become possible to improve the smoothness without damaging the magnetic disk or its magnetic layer, and have found a magnetic disk polishing method and apparatus that dramatically improve the track quality. ..

The shape of the jet nozzle of the air nozzle used in the present invention is such that the ratio of the groove length to the groove width is 15 to 15.
It is preferably in the range of 60, preferably 25 to 50. If the shape ratio of the ejection port is far outside the above-mentioned limited range, it becomes difficult to obtain the optimum polished state of the magnetic disk surface even by adjusting the air pressure supplied to the air nozzle. In particular, if the shape ratio of the ejection port falls below the limited range, the air pressure blown from the air nozzle fluctuates, and the pressure contact between the magnetic disk and the polishing tape may become unstable. On the other hand, when the amount exceeds the limited range, the amount of air blown from the air-nozzle decreases, polishing unevenness occurs, and the uniformity of the polished surface cannot be maintained.

The air pressure supplied to the air nozzle is
The range of 0.02 to 0.20 MPa, preferably 0.03 to 0.15 MPa is preferable. When the air pressure is below the limited range, the pressure contact between the magnetic disk and the polishing tape becomes insufficient, and when the air pressure exceeds the limited range, the magnetic disk and the polishing tape resonate,
So-called tape squeal may occur.

The abrasive tape used in the present invention includes abrasive grains made of materials such as alumina, chromium oxide, iron oxide, and carborundum, and the size of the abrasive grains is preferably 8000 to 15000. ..

The magnetic disk used in this example had a polyester film of a predetermined thickness with a thickness of 0.5 μm on both sides.
The magnetic paint is applied so as to be dried and dried, and the magnetic paint is composed of magnetic powder, a binder, an antistatic agent, an abrasive, a lubricant, an organic solvent, and the like.

Embodiments of the present invention will now be described in more detail with reference to the drawings (Embodiment 1) (FIG. 1) is a main front view of a polishing apparatus of the present invention, and (FIG. 2) is an enlarged view of an air nozzle. It is a thing.

The magnetic disk 1 is formed by coating a metal magnetic film on both sides of a polyester film having a thickness of 62 μm and punching it out for 3.5 inches.
It is held by the chucking portion 2 a and the disc retainer 3. The rotation shaft 2 has a variable rotation speed, is integrated with a swing mechanism (not shown), and has a function of swinging horizontally with respect to the magnetic surface of the magnetic disk 1.

On the upper surface side 1a of the magnetic disk 1, there is a first
A first polishing tape 5 running while being mounted on the roller 4 is pressed against it, and a second polishing tape 5 running while being mounted on a second roller 4a with respect to the lower surface 1b of the magnetic disk 1. -Pup 5a is pressed.

The first air nozzle 6 and the second air nozzle 6a, which are arranged opposite to the rollers, are fixed to the frame 7 at predetermined positions, and the first jet port 6b of the air nozzle and The second ejection ports 6c are opened on the upper surface side 1a of the magnetic disk 1 and the lower surface side 1b of the magnetic disk 1 with a distance of about 5 mm. The shape of the ejection port of the air nozzle was such that the ratio of the groove width 6d to the groove length 6e (hereinafter referred to as the nozzle shape ratio) was 38.

The above-mentioned polishing tape is interposed by a guide roller (not shown) arranged on the frame 7, and the first polishing tape 5 passes through the first roller 4 and the second polishing tape. The tapes 5a are provided so as to travel via the second rollers 4a. The polishing tape used was a polyethylene terephthalate film coated with alumina abrasive grains having an average particle size of about 1 μm.

Next, the operation of this embodiment having the above configuration will be described. The magnetic disk 1 is rotated at about 1000 rpm while being swung in the direction of the arrow by the rotating shaft 2. The swing conditions are distance ± 15mm, speed 6mm / sec.
It is a degree.

The pressure contact between the magnetic disk 1 and the polishing tape is
Air arranged opposite to the roller-first air of the nozzle-
It is obtained by the air pressure blown from the nozzle 6 and the second air-nozzle 6a.

Pressurized air is guided to the air nozzle through the frame 7, and the first jet port 6b and the second jet port 6c are provided.
Erupted from. The air-pressurized air supplied to the nozzle-is variable by adjusting the pressure, and the pressure is 0.06MPa.
Set to. The polishing tapes run at a speed of about 2 mm / sec. Under the above conditions, 100 magnetic disks were each polished for 10 seconds to prepare samples.

(Example 2) to (Comparative Example 4) Samples were prepared in the same manner as in Example 1, except that the nozzle shape ratio and air-pressure conditions were as shown in (Table 1).

(Comparative Example 5) to (Comparative Example 7) In Example 1, one set of air nozzle, roller and polishing tape was used, and the polishing conditions were as shown in (Table 1). A sample was prepared in the same manner except polishing.

[0031]

[Table 1]

Each of the above samples was assembled into a 3.5 inch shell. The following measurement and evaluation were performed on each magnetic disk sample thus obtained, and the results are shown in (Table 2). (1) Track quality floppy disk drive (NEC company: FD1331:
-Mount each magnetic disk sample on 13.3MB mat, record 2f (500kHz) signals on all tracks, and perform missing pulse (hereinafter referred to as MP) and modulation (hereinafter referred to as MO).
Called). However, the error slice level should be 70% or less for MP and 10% for MO.
The defect occurrence rate in the above case was determined. (2) Observation of Defects After measuring the track quality, the part where the MP was generated was observed using an electron microscope, and the cause of the defects was distinguished between polishing scratches and other causes. In addition, five samples were randomly sampled from each magnetic disk sample, and a three-dimensional surface roughness meter (WY
The surface roughness of the polished surface was measured by KO) and the surface uniformity was evaluated using the following symbols.

◯: Good Δ: Slightly bad ×: Bad

[0034]

[Table 2]

As is clear from (Table 2), according to the present invention, the surface of the magnetic disk can be easily polished, there are few polishing scratches, and uniform polishing can be obtained with high efficiency. Further, it can be seen that a method and apparatus for polishing a magnetic disk, which is free of MP and has a small MO and excellent track quality, can be obtained.

[0036]

As described above, according to the present invention, by arranging two sets of the air nozzle and the polishing tape which runs while interposing the roller in the horizontal direction with respect to the surface of the magnetic disk, the polishing is performed. The running condition is improved by suppressing the unbalanced component of the stress applied to the magnetic disk at the time. Further, by specifying the nozzle shape ratio and the range of air-pressure, the surface smoothness of the magnetic disk can be more uniformly improved, and a magnetic disk polishing method and apparatus for dramatically improving track quality can be provided. it can.

[Brief description of drawings]

FIG. 1 is a front view of a polishing apparatus used in an example of the present invention.

FIG. 2 is an enlarged view of an air-nozzle.

[Explanation of symbols]

 1 magnetic disk 1a upper surface side of magnetic disk 1b lower surface side of magnetic disk 2 rotating shaft 2a chucking portion 3 disk retainer 4 first roller 4a second roller 5 first polishing tape 5a second polishing tape 6 First air-nozzle 6a Second air-nozzle 6b First jet 6c Second jet 6d Groove width 6e Groove length 7 Frame

Claims (5)

[Claims] 1. A polishing method in which a polishing tape and a magnetic disk surface are brought into pressure contact with each other by pressurized air, and the polishing tape is run by interposing it between an air nozzle for ejecting the pressurized air and a roller. -A pair of magnetic tapes are arranged in a horizontal direction with respect to the surface of the magnetic disk. 2. An air nozzle and a polishing tape, which is run by being interposed in a roller, are opposed to each other on both sides of the magnetic disk,
The method of polishing a magnetic disk according to claim 1, wherein the magnetic disk is provided at a position of 180 degrees with respect to the center of the magnetic disk. 3. The method for polishing a magnetic disk according to claim 1, wherein the ratio of the groove length to the groove width of the air nozzle is 15 or more and less than 60. 4. The pressure of the pressurized air is 0.02 MPa or more, 0.20 M
The method for polishing a magnetic disk according to claim 1, wherein it is less than Pa. 5. A polishing apparatus for a magnetic disk, which supports a magnetic disk, rotates, and swings, and a polishing tape which is run by interposing air nozzles and rollers ejecting toward the surface of the magnetic disk. An apparatus for polishing a magnetic disk, comprising two sets of a groove and a groove in a horizontal direction relative to the surface of the magnetic disk.