JPH027225A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To remove the dust sticking to a surface by subjecting to a lapping treatment before the produced recording medium is taken up. CONSTITUTION:A lapping tape 14 which laps the surface of the nonmagnetic base 2 traveling from a guide roll 7 to a take-up roll 4 is disposed on said surface. The lapping tape 14 which removes the dust sticking to the surface of the base 2 travels in an arrow B direction and is taken up on a lapping tape take-up roll 16 disposed near the lapping roll 13. The traveling speed of this tape 14 is so set that the tape travels at the speed different from the traveling speed of the base 2. The dust sticking to the surface of the base 2 is thus surely removed. Sticking of the dust to the magnetic layer formed on the already taken-up base 2 is obviated in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method for manufacturing a magnetic recording medium in which a metal magnetic film is formed on a nonmagnetic support.

B0 Summary of the Invention The present invention involves forming a metal magnetic film on a non-magnetic support by a thin film forming means, lapping the surface of the metal magnetic film and/or the surface of the non-magnetic support, and then winding it up. Surface etc. of Magnetic Recording Media C0 Prior Art Conventionally, magnetic recording media have been prepared by disposing a powder magnetic material such as oxide magnetic powder or alloy magnetic powder on a non-magnetic support using a vinyl chloride-vinyl acetate copolymer.

BACKGROUND ART Coating-type magnetic recording media, which are manufactured by coating and drying a magnetic paint dispersed in an organic binder such as polyester resin or polyurethane resin, are widely used.

On the other hand, with the increasing demand for high-density magnetic recording, metal magnetic materials such as Go-Ni alloy, Co-Cr alloy, Co-0, etc. A so-called metal magnetic i-film type magnetic recording medium, which is directly deposited on a non-magnetic support such as a polyester film or a polyimide film, by a method such as ion blating method, etc.) has been proposed and is attracting attention. This metal magnetic thin film type magnetic recording medium has excellent coercive force and squareness ratio,
Not only does it have excellent electromagnetic conversion characteristics at short wavelengths, but the thickness of the magnetic layer can be made extremely thin so that the thickness loss during recording demagnetization and reproduction is extremely small. It has a number of advantages, including the ability to increase the packing density of the magnetic material since there is no need to mix in a certain binder.

D0 Problem to be Solved by the Invention By the way, when a metal magnetic film is formed by the above-mentioned thin film forming means, dust and solidified magnetic material generated during film formation may adhere to the surface of a non-magnetic support. This may cause dropouts.

In particular, when a non-magnetic support is run over an enormous length to form a film and then is wound up, a large amount of static electricity is generated, and dust inside the device can accumulate on the surface of the support or on the surface of the magnetic layer on which the magnetic layer has been formed. It may adhere to the surface of the film and significantly deteriorate the quality of the manufactured magnetic recording medium.

Therefore, in order to improve the quality of the magnetic recording medium, there has been a technique for removing magnetic dust, etc. using magnets arranged to sandwich the support, as disclosed in, for example, Japanese Unexamined Patent Publication No. 63-42033. It has been known.

However, although it is possible to remove magnetic dust using the above method, it is not possible to effectively remove other dust.Furthermore, in the actual production of magnetic recording media, dust that has less magnetic properties than the magnetic dust mentioned above cannot be effectively removed. In view of the large amount of dust, the above method cannot sufficiently improve the quality of the magnetic recording medium manufactured.

Therefore, the present invention was proposed in view of the above-mentioned conventional situation, and regardless of whether the dust adhering to the surface of a non-magnetic support or the surface of a magnetic film serving as a magnetic layer is magnetic dust, the dust can be removed. The purpose of this invention is to effectively eliminate this problem and improve the quality of manufactured magnetic recording media.

E6 Means for Solving the Problems In order to achieve the above object, the present invention forms a metal magnetic film on a non-magnetic support by a thin film forming means, and forms the surface of the metal magnetic film and/or the non-magnetic support. It is characterized by being rolled up after the surface is subjected to a ramping treatment.

The magnetic recording medium manufactured according to the present invention is a so-called metal magnetic "a-layer" magnetic recording medium in which a metal magnetic thin film is used as a magnetic layer, and the metal material constituting the metal magnetic thin film is usually of this kind. For example, magnetic metals such as Fe, Co, Ni, Fe-Co, Co-Ni, Fe-Co-Ni, C
o-Cr, Fe-Co-Cr, Co-Ni-Cr, Fe
-Co-Ni-Cr, etc.

Commonly used materials can be used for the nonmagnetic support, such as polyester resins such as polyethylene terephthalate and polyethylene-2,6-naphthalate, aromatic polyamide films, and polyimide resin films.

In the present invention, after the metal magnetic film is formed by a thin film forming means, it is necessary to perform a lapping process and then wind it up.

The above-mentioned thin film forming means include vacuum evaporation method, sputtering method,
Any film forming method for this type of magnetic recording medium, such as the ion blating method or the plating method, can be used. Regarding the vacuum evaporation method mentioned above, when the film is formed by so-called oblique evaporation, Any method may be used, regardless of whether the film is formed by vertical evaporation or not.

Further, the above-mentioned lapping treatment may be performed on the surface of the metal magnetic film formed by the above method or the surface of the non-magnetic support on which the metal magnetic film is formed, and furthermore, the surface of the metal magnetic film and the surface of the non-magnetic support. It may be applied to both. Note that, although it is preferable that the wrapping is performed in the same direction as the running direction of the nonmagnetic support, wrapping may be performed in the opposite direction.

F9 Effect According to the method for manufacturing a magnetic recording medium of the present invention having the above-described configuration, lapping treatment is performed on the surface of the metal magnetic film and/or the surface of the nonmagnetic support of the magnetic recording medium to be manufactured. Therefore, dust adhering to the surface of the metal magnetic film and/or the surface of the non-magnetic support is removed, and deterioration in quality of the magnetic recording medium is eliminated.

G. EXAMPLE Hereinafter, an example of a method for manufacturing a magnetic recording medium according to the present invention will be specifically described.

First, an example of a manufacturing apparatus used in the method of manufacturing a magnetic recording medium according to the present invention will be described.

As shown in FIG. 1, in this manufacturing apparatus, a tape-shaped non-magnetic support 2 is placed in a vacuum chamber 1 whose interior is in a vacuum state, from a feed roll 3 that rotates at a constant speed clockwise in the figure. In the figure, the winding rollers 4 are sequentially run on a winding roll 4 which rotates at a constant speed in a counterclockwise direction.

In the middle of the run from the feed roll 3 to the take-up roll 4 side, the non-magnetic support 2 is provided so as to be pulled out downward in the figure, and has a diameter larger than the diameter of each of the rolls 3.4. The cooling can 5 is provided to rotate at a constant speed clockwise in the figure. The feed roll 31, take-up roll 4, and cooling can 5 each have a cylindrical shape with a length approximately the same as the width of the non-magnetic support 2, and the cooling can 5 has an internal structure. A cooling device (not shown) is provided to suppress deformation of the non-magnetic support 2 due to temperature rise.

Therefore, the non-magnetic support 2 is sequentially sent out from the feed roll 3, passes through the circumferential surface of the cooling can 5, and is wound onto the take-up roll 4.

Note that guide rolls 6.7 are provided between the feed roll 3 and the cooling can 5 and between the cooling can 5 and the take-up roll 4, respectively, so that the cooling can 4 and From the cooling can 5 to the winding roll 4
A predetermined tension is applied to the non-magnetic support 2 running over the area, so that the non-magnetic support 2 runs smoothly. Further, it is desirable that the surface roughness of the winding roll 40 according to the present device is 10 μm or less in terms of Ra (center line average roughness). This is because the surface roughness of the winding roll 4 greatly affects the amount of dropout of the magnetic recording medium wound around this roll 4, and in addition to the lapping process described below, the surface roughness of the winding roll 4 is lowered. This is because the quality of the manufactured magnetic recording medium can thereby be further improved.

Further, in the vacuum chamber 1, a storage container 8 is provided below the cooling can 5, and the storage container 8 is filled with a metal magnetic material 9. Further, on the side of the cooling can 5, a heating means 1 constituted by an electron beam gun or the like is provided.
0 is set.

This heating means 10 heats and evaporates the metal magnetic material 9 filled in the storage container 8, and the metal magnetic material 9 evaporated by this heating means 10 moves around the circumferential surface of the cooling can 5 at a constant speed. A magnetic layer is deposited on a traveling non-magnetic support 2.

Further, a shutter 11 curved so as to face the circumferential surface of the cooling can 5 is disposed between the cooling can 5 and the storage container 8 for the metal magnetic material 9 and in the vicinity of the cooling can 5. It is set up. This shutter 11 covers a predetermined range of the non-magnetic support 2 so that the metal magnetic material 9 is deposited obliquely at a predetermined angle range with respect to the non-magnetic support 2.

Further, in this apparatus, a roughening roll 13 is provided that performs a ramping treatment on the surface of the non-magnetic support 2 that runs from the guide roll 7 to the take-up roll 4.

This wrapping roll 13 is configured to rotate in the clockwise direction in FIG. It is designed to run in direction B. This wrapping tape 14 is wound in large numbers around a wrapping tape feed roll 15 disposed near the roughing roll 13 and sequentially runs on the wrapping roll 13, and is further disposed near the roughening roll 13. The roughening tape is wound onto a winding roll 16. The running speed of the roughening tape 14 is set to be different from the running speed of the non-magnetic support 20, so that dust attached to the surface of the non-magnetic support 2 can be reliably removed. It is being done.

According to the manufacturing apparatus having the above-described configuration, after the metal magnetic material 9 is deposited, the wrapping process is performed using the roughening tape 14, so that even if the magnetic recording medium is sequentially wound by the winding roll 4, Dust adhering to the surface of the non-magnetic support 2 does not adhere to the magnetic layer formed on the non-magnetic support 2 that has already been wound up.

In addition, although the above-described apparatus adopts a configuration in which the surface of the non-magnetic support 20 is subjected to lapping treatment, the present invention is not limited to the above-mentioned embodiments, and may be applied to, for example, a device in which the surface of a metal magnetic film is subjected to lapping treatment. Alternatively, the surface of the non-magnetic support 2 and the surface of the metal magnetic film may be subjected to lapping treatment.

The present inventors carried out the above-mentioned wrapping process using various methods explained below, and measured the amount of dropout of these magnetic recording media. compared to the amount. Note that this dropout amount is 10 μsec
The number of stitches is defined as one case where the recording level is -16 dB below the reference level.

A magnetic recording medium was manufactured by using a menschluffing tape No. 110-2000 and slidingly contacting the meshwrapping tape in the same direction as the running direction of the nonmagnetic support 2. As a result of counting the amount of dropouts of magnetic recording media subjected to wrapping processing using this method, the amount of dropouts was 10 pieces per minute.

Disaster relief plate l Same as the roughing tape used in Example 1 above.
A magnetic recording medium was manufactured by using a roughing tape and sliding the roughing tape in a direction opposite to the running direction of the nonmagnetic support 2. Drop roughness of magnetic recording medium wrapped by this method
As a result of counting t, the dropout amount was 15 pieces per minute.

Note that some scratches were found on the surface of the nonmagnetic support 20 obtained by this method.

A magnetic recording medium was manufactured by using a mesh roughing tape of Jitsuhoshi Kashu No. 3000 and slidingly contacting the roughing tape in the same direction as the running direction of the nonmagnetic support. As a result of counting the amount of dropouts of the magnetic recording medium subjected to the ramping process using this method, the amount of dropouts was 8 pieces per minute.

The dropout rate of the magnetic recording medium manufactured without performing the above-mentioned wrapping process was 80 pieces per minute.

As is clear from a comparison of the dropout amount in each of the above examples and the dropout amount in the comparative example, the dropout amount of the magnetic recording medium manufactured by adopting the ramping process is greatly reduced. I understand.

In addition, the present inventors further set the surface roughness of the winding reroll 4 to the values shown in Table 1 below to manufacture magnetic recording media (Examples A to C and Comparative Example), and each The amount of dropout was measured.

The surface roughness of the winding roll 4 in Table 1 is expressed as center line average roughness (Ra), and the dropout amount is defined as the amount of dropout when the recording level is lower than the reference level for 10 μsec or more. The case where the level was below 16 dB was counted as one.
(Hereinafter, blank space) Table 1 As is clear from Table 1 above, the winding roll rule 4
It can be seen that by setting the zero surface roughness low, the amount of dropout of the manufactured magnetic recording medium can be reduced.

Therefore, a magnetic recording medium with even fewer dropouts can be manufactured by performing a lapping process after the metal magnetic film is deposited and then winding it up using the winding roll 4 whose surface roughness is set to be low. can.

H0 Effects of the Invention As is clear from the description of the above embodiments, according to the method for manufacturing a magnetic recording medium of the present invention, the ramping process is performed before the manufactured magnetic recording medium is wound up. In this way, dust attached to the surface of the magnetic recording medium is removed, and a magnetic recording medium with excellent electromagnetic conversion characteristics and less dropouts can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a magnetic recording medium manufacturing apparatus. 2...Support 4...Take-up roll 13...Roughing roll 14...Lamping tape patent Applicant Sony Corporation representative Patent attorney Akira Koike (and 2 others) Proceeding supervisor Written (spontaneous) August 17, 1999

Claims (1)

[Claims] A method for producing a magnetic recording medium, comprising forming a metal magnetic film on a non-magnetic support by a thin film forming means, lapping the surface of the metal magnetic film and/or the surface of the non-magnetic support, and then winding it up. .