JPH05143978A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To suppress the deterioration in reproduced output characteristics by polishing the magnetic recording medium with a polishing tape, thereby removing the microprojections on the surface of a protective film. CONSTITUTION:The magnetic recording medium is formed by laminating a magnetic layer and the protective film on a substrate. The surface of the protective film constituted of an inorg. material is polished by using the polishing tape 2 of #1000 to 4000 meshes. The very small abnormal projections are formed on the surface of the protective film by the very small abnormal projections generated spoontaneously on the magnetic layer in a production process. The abnormal projections are chipped off by the polishing tape 2, by which the damages of the head are decreased. The damages are drastically decreased and the reproduced output characteristics are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetic recording medium, in particular, a vapor deposition tape having a metal thin film deposited thereon.

[0002]

2. Description of the Related Art In a magnetic recording medium formed by depositing a metal thin film such as a vapor-deposited tape, it is possible to remarkably improve the durability by providing minute protrusions on the base surface and reducing the true contact area with the head. .. For example, in ME (metal evaporated) tape applied to high band 8 mm,
By using a lubricant for a metal thin film or the like, durability with practically no problem is obtained.

On the other hand, in the digital VTR, since the data transfer rate becomes high as well as the high recording density, the relative speed between the magnetic head and the magnetic recording medium such as a tape is
More than twice as much as analog recording is required. In a VTR in which the head rotates at a high speed in this way, the damage to the tape increases, so that it becomes necessary to further improve the durability of the tape itself.

For this reason, a structure has been proposed in which a protective film is provided on the magnetic layer, and in this case, a very large effect is obtained in order to improve the durability especially in the stationary mode.

However, regarding the durability in the mode where the tape is repeatedly used in the running state, that is, the so-called shuttle durability, there is a problem that the tape is not damaged at all, but the head is seriously damaged and the reproduction output is remarkably lowered. ..

That is, since the magnetic material and its oxide are relatively soft, even if there are minute abnormal projections on the surface, they are scraped off by the sliding of the head and do not damage the head. As described above, when the protective film is provided on the magnetic layer, the protective film itself is made of a hard material, and the abnormal protrusions on the surface are hard so that the head is damaged even if the tape itself is not damaged. Becomes Particularly, for example, in a head having a so-called metal-in-gap type structure in which a metal thin film having a high magnetic permeability is arranged in the magnetic gap forming portion of a ferrite core, the hardness of the ferrite and the metal thin film is different, which causes uneven wear. It may happen.

Such fine protrusions naturally occur on the surface of the magnetic layer when the magnetic layer is deposited by vapor deposition, sputtering, etc., in addition to the case where the fine protrusions are provided on the base as described above. Since minute abnormal protrusions are generated, abnormal protrusions also occur on the surface of the protective film deposited thereon, and this protective film is deposited, sputtered, plasma CVD (chemical vapor deposition method), ECR
(Electron Cyclotron Resonance) Even when a film is formed by plasma CVD, ion plating, or the like, minute abnormal protrusions are generated, which similarly causes damage to the head.

[0008]

SUMMARY OF THE INVENTION The present invention avoids damage to the head due to abnormal protrusions on the protective film provided on the surface of the magnetic recording medium as described above, suppresses deterioration of reproduction output characteristics, and improves reliability. Improve the sex.

[0009]

In the method of manufacturing a magnetic recording medium according to the present invention, at least a magnetic layer and a protective film 13 are sequentially formed on a substrate as shown in a manufacturing process chart of an example thereof as shown in FIG. The magnetic recording medium 1 is polished with a polishing tape 2.

According to another aspect of the present invention, in the above-described method of manufacturing a magnetic recording medium, a polishing tape having a mesh number of 1000 to 4000 is used as the polishing tape 2.

In yet another aspect of the present invention, in the above-described method of manufacturing a magnetic recording medium, the protective film 13 is made of an inorganic material.

[0012]

As described above, according to the present invention, by polishing the surface of the magnetic recording medium 1 with the polishing tape, the abnormal protrusions generated on the protective film 13 are polished and scraped off, thereby damaging the head. Therefore, the reproduction output characteristics can be improved.

According to another aspect of the present invention, by using a polishing tape having a mesh of No. 1000 to No. 4000, it is possible to more reliably suppress damage to the head and improve the reproduction output characteristics. It was possible to obtain a magnetic recording medium which was excellent in running property.

Furthermore, in another embodiment of the present invention, the protective film 13 of the magnetic recording medium 1 is made of an inorganic material, and the polishing tape 2 is formed on the magnetic recording medium 1 as described above. By polishing by using it, damage to the head can be greatly reduced, and the reproduction output characteristic can be improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a method of manufacturing a magnetic recording medium according to the present invention will be described in detail below with reference to FIGS. In this case, an example in which the present invention is applied to a metal vapor deposition tape as a magnetic recording medium will be shown.

First, as shown in the schematic enlarged sectional view of FIG. 2, Co ₈₀ Ni ₂₀ (wt) is formed on a substrate 11 made of PET (polyethylene terephthalate) having a thickness of about 10 μm.
%) Was deposited by oblique vapor deposition in oxygen. In this case, the minimum angle theta _{mi n} from a direction perpendicular to the minimum angle or film surface of the magnetic recording medium 5 obliquely evaporated
Was set to θ _min = 45 ° and the thickness was set to 2000Å.

On top of this, for example, magnetron DC
A protective film 13 made of carbon or the like having a thickness of 200 is formed by sputtering at a pressure of 10 mTorr in Ar gas.
The film was formed as Å.

With respect to the magnetic recording medium 1 thus formed, as shown in FIG. 1, the surface on the protective film 13 side of the magnetic recording medium 1 and the polishing surface side of the polishing tape 2 are brought into contact with each other. Then, for example, it was slid on the peripheral surface of a cylindrical drum for polishing. In this case, the magnetic recording medium 1 and the polishing tape 2 are run at different running speeds.
For example, in this case, the magnetic recording medium 1 was run at 100 m / min and the polishing tape 2 was run at 5 cm / min for polishing.

The material and particle size of the polishing tape 2 were changed by the above method as shown in each of the following examples, and the change in reproduction output due to head damage and uneven wear of the head was measured. As the polishing tape, GC series made of SiC and WA series made of Al ₂ O ₃ manufactured by MIPOX Co. were used with different meshes.

Example 1 As a polishing tape, GC series GC-1000 (trade name) was used for polishing. In this case, the mesh is 10
No. 00, the particle size was 16 μm.

Example 2 As a polishing tape, GC series GC-2000 (trade name) was used for polishing. In this case, the mesh is 20
No. 00, the particle size was 9 μm.

Example 3 As a polishing tape, GC series GC-4000 (trade name) was used for polishing. In this case, the mesh is 40
No. 00, the particle size was 3 μm.

Example 4 As a polishing tape, WA series WA-1000 (trade name) was used for polishing. In this case, the mesh is 10
No. 00, the particle size was 16 μm.

Example 5 As a polishing tape, WA series WA-2000 (trade name) was used for polishing. In this case, the mesh is 20
No. 00, the particle size was 9 μm.

Example 6 As a polishing tape, WA series WA-4000 (trade name) was used for polishing. In this case, the mesh is 40
No. 00, the particle size was 3 μm.

Reference Example 1 As a polishing tape, GC series GC-800 (trade name) was used for polishing. In this case, the mesh is 80
No. 0, the particle size was 20 μm.

Reference Example 2 As a polishing tape, GC series GC-8000 (trade name) was used for polishing. In this case, the mesh is 80
No. 00, the particle size was 1 μm.

Reference Example 3 WA-800 (trade name) of WA series was used as a polishing tape for polishing. In this case, the mesh is 80
No. 0, the particle size was 20 μm.

Reference Example 4 WA-8000 (trade name) of WA series was used as a polishing tape for polishing. In this case, the mesh is 80
No. 00, the particle size was 1 μm.

For each magnetic recording medium thus formed, an EV-S1 of 8 mm VTR was used as a magnetic head.
(Manufactured by Sony, product name) was repeatedly run for 100 passes to measure durability. Further, the damage of the head was observed under a microscope, and when there was no scratch, it was indicated by ⊚, and as the amount of scratch increased, it was indicated by ◯, Δ, and ×, respectively. The results are shown in Table 1.

[0031]

[Table 1]

As can be seen from these results, according to the manufacturing method of the present invention, by polishing with the polishing tape 2, it is possible to reduce the damage to the head and suppress the reduction of the reproduction output.

Particularly, the mesh is numbered from 1000 to 400.
By setting it to No. 0, the damage given to the head was surely reduced, and the reduction of the reproduction output could be sufficiently suppressed. This is because when the mesh is less than 1000 mesh, the grain size of the polished surface is as coarse as about 2 μm, which damages the protective film and causes further abrasion powder to be attached to damage the head. When the mesh exceeds 4000, the grain size becomes smaller than 3 μm, which is considered to be because the relatively large protrusion cannot be polished and the head is damaged.

In this case, in each of Examples 1 to 6, sticking between the magnetic recording medium and the head did not occur, and the running property could be improved.

In the above example, the magnetic recording medium 1
It is the result of the measurement when carbon is deposited as the protective film 13 of the above. Other than that, for example, SiO ₂ , Si ₃ N
By applying the present invention to a magnetic recording medium coated with a protective film 13 made of various inorganic materials such as ₄ , SiN _x , BN, Al ₂ O ₃ , ZnO _{2 and the} like, it is possible to surely suppress head damage. It was possible to avoid a decrease in reproduction output.

The present invention is not limited to the above-described examples, and polishing tapes made of various polishing materials can be used for magnetic recording media having various other material configurations.

[0037]

As described above, according to the method of manufacturing a magnetic recording medium of the present invention, the minute abnormal protrusions formed on the surface of the protective film are polished to surely suppress the damage to the head. As a result, the deterioration of the reproduction output characteristics can be suppressed, and the reliability of the magnetic recording medium can be improved.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of an example of a method of manufacturing a magnetic recording medium of the present invention.

FIG. 2 is a schematic enlarged cross-sectional view of an example of a magnetic recording medium.

[Explanation of symbols]

 1 Magnetic Recording Medium 2 Polishing Tape 11 Substrate 12 Magnetic Layer 13 Protective Film

Claims (3)

[Claims] 1. A method of manufacturing a magnetic recording medium, which comprises polishing a magnetic recording medium, in which at least a magnetic layer and a protective film are sequentially formed on a substrate, with a polishing tape. 2. The method for manufacturing a magnetic recording medium according to claim 1, wherein the polishing tape has a mesh number of 1000 to 40.
A method of manufacturing a magnetic recording medium, characterized in that an abrasive tape No. 00 is used. 3. The method of manufacturing a magnetic recording medium according to claim 1, wherein the protective film is made of an inorganic material.