JPS62139126A - Manufacture of magnetic medium - Google Patents

Abstract

PURPOSE:To make wall thickness uniform by applying a magnetic layer to the back of an overcoat layer, then attaching a slightly thick base to the back of the magnetic layer and peeling off a dummy tape out of the overcoat layer after the all the overcoat layer, the magnetic layer and the base closely adhere. CONSTITUTION:There is a fixed layer 12 buried by a glue, etc., on the surface of the base 11, and the magnetic layer 13 including a magnetic material such as strontium ferrite attaches to the upper surface of the fixed layer 12. Then the extremely thin overcoat layer 14 is formed on the surface of the magnetic layer 13. Since the strength of the extremely thin overcoat layer 14 is maintained by a dummy tape 15, the overcoat layer 14 is smoothly supplied at the time of coating the magnetic material to the dummy coat layer, and no cutting occurs. The dummy tape 15 an be easily separated from the magnetic medium formed by peeling off the dummy tape 15 after the magnetic layer 13 is dried. Thus the overcoat layer 14 with a uniform wall thickness can be constituted to attain a uniform quality.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of manufacturing a magnetic medium that can form an extremely smooth surface of an overcoat layer that contacts a magnetic head and is easy to manufacture. be.

[Conventional technology]

BACKGROUND ART Conventionally, magnetic media such as magnetic tapes, magnetic floppies, magnetic cards, etc., in which a magnetic material is coated on a base and various information is magnetically stored on the magnetic material using a magnetic head, have been widely used. This conventional magnetic medium is formed by coating a magnetic material such as strontium ferrite or barium ferrite on a plastic base such as polyethylene. however,
If a magnetic head is brought into direct contact with a magnetic material, the particles of the magnetic material will wear the magnetic head, so an overcoat layer that forms a smooth surface with sliding properties is always applied to the surface of the magnetic material. This overcoat layer made the surface of the magnetic medium smooth and acted as a lubricant even when the magnetic head came into contact with it, thereby preventing wear of the magnetic head. Now, in recent years, it has begun to manufacture magnetic tapes, magnetic disks, and magnetic cards using strontium ferrite as a material instead of barium ferrite and using high antimagnetic properties.

This is because, due to its high magnetic density, it can be used for perpendicular magnetic information recording, etc., using the same manufacturing process technology as in the past. However, compared to the conventionally used normalium ferrite, strontium ferrite has problems in that the size of the magnetic particles when applied to the base is unstable, and the shape of the particles becomes thick. Even if an overcoat layer was attached to the surface of the magnetic medium, the surface often still became uneven.

The cross-sectional structure of this conventional magnetic medium is explained with reference to Figure 1. The base 1 is made of polyethylene, etc., and the surface of the base 1 is made of a mixture of a magnetic material such as strontium ferrite and a binder such as glue. A magnetic layer 2 is coated and fixed, and an extremely thin overcoat layer 3 is coated on the surface of the magnetic layer 2. However, since these magnetic particles in the magnetic layer 2 containing strontium ferrite have large sizes as described above, even if a thin overcoat layer 3 is applied, the unevenness thereof will be exposed on the surface of the overcoat layer 3. Therefore, when the head slides in contact with the overcoat layer 3 itself having irregularities, the magnetic head is abraded, making it impossible to write or read information stably over a long period of time. In addition, in order to prevent this drawback, in the manufacturing process of magnetic media,
The surface of the overcoat layer 3 may be polished to make it smooth, but there is a limit to the smoothing work, and the coater device for the overcoat layer 3 wears out quickly during the production process. It left behind various problems.

In order to reduce unevenness on the surface of this magnetic medium, a thin overcoat layer is brought into contact with a smooth surface in advance, and a magnetic layer is applied to the back side of the overcoat layer in this state. A manufacturing method has also been devised in which unevenness caused by the magnetic material is not exposed on the front side of the overcoat layer by attaching it to the back surface of the magnetic layer.

[Problem that the invention seeks to solve]

However, in this newly proposed manufacturing method in which a magnetic material is applied to the overcoat layer, the overcoat layer is extremely thin, so the overcoat layer may be cut during the manufacturing process, or the thickness may change due to fluctuations in tensile force. It had the disadvantage of causing a phenomenon.

[Means for solving problems]

In the present invention, a thin overcoat layer and a slightly thick dummy tape are brought into close contact with each other, and a magnetic layer is applied to the back side of the overcoat layer with the back side of the dummy tape in contact with a smooth surface. To provide a method for manufacturing a magnetic medium, characterized in that a slightly thick base is attached to the back surface of the magnetic layer, and after the overcoat layer, the magnetic layer, and the base are in close contact with each other, the dummy tape is peeled off from the overcoat layer. It is.

[Effect]

In the present invention, the overcoat layer and a thick dummy tape are brought into close contact with each other in advance, and while the strength is maintained by the dummy tape, a magnetic material is applied to the back side of the overcoat layer.
Thereafter, the base is brought into close contact with the back surface of the magnetic material to form three layers, and after the magnetic layer is solidified, the dummy tape is peeled off from the overcoat layer, making it possible to manufacture a magnetic medium in an extremely stable manner.

〔Example〕

゛An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a cross section of a magnetic medium manufactured according to the present invention. On the surface of the base 11 is a pinned layer 12 filled with glue or the like, and on the top surface of the pinned layer 12 is a magnetic material such as strontium ferrite. A magnetic layer 13 containing material is deposited. An extremely thin overcoat layer 14 is formed on the surface of the magnetic layer 13.

Next, the manufacturing method in this example will be explained.

FIG. 3 shows the state at the preliminary stage of the manufacturing process, in which a thick dummy tape 15 is attached to the back side of the thin overcoat layer 14 made of polyester or the like mentioned above, and the overcoat layer 14 and dummy tape 15
are supplied as one unit, and both are in a state where they can be easily peeled off in subsequent processing. In this state, the load such as tension is maintained by the strength of the dummy tape 15, and the overcoat layer 14 can be considered to be held by the dummy tape 15. A protective tape 16 is formed by the overcoat layer 14 and the dummy tape 15.

Next, FIG. 4 shows the state during the manufacturing process, and the smooth roll 17, which has a slightly large diameter, has been processed to have an extremely flat surface and is rotating in the direction of the arrow in FIG. 4. Then, the supply roll 18 on which the above-mentioned protective tape 16 is wrapped pulls out the protective tape 16 from one end, and its back side (the back side is the dummy tape 15 side) is in close contact with the surface of the smooth roll 17. 15 is separated and wound up on a recovery roll 19. Then, the surface of the protective tape 16 (overcoat layer 14 side)
The nozzle 21 of the hopper 20 is brought close to the
A magnetic material 22 is stored in liquid form in the ompper 20. A slightly thick base 11 made of polyethylene or the like is wound around the base roll 23, and this base 11 is tightly attached to the slightly lower surface of the smooth roll 17, and is formed by the overcoat layer 14 and the base 11. The magnetic tape 24 is wound in the direction of a take-up roll 25.

In this configuration, the protective tape 16 sequentially pulled out from the supply roll 18 is wound around the outer circumferential surface of the smooth roll 17, and the protective tape 16 is wrapped around the outer circumferential surface of the smooth roll 17 while keeping the surface flat.
Transfer to the outer periphery of 7. During this rolling, the magnetic material 22 housed in the homper 20 is sprayed thinly from the nozzle 21 to form the overcoat layer 14.
It will be applied to the surface of Then, when the base 1 has dried to some extent, it is unwound from the base roll 23.
1 comes into close contact with the surface of the magnetic layer 13 formed of the magnetic material 22, and when both are in close contact and dry, the dummy tape 15 is peeled off from the overcoat layer 14, and the dummy tape 15 and the magnetic tape 24 are rolled into a smooth roll. 1
It is separated below 7. And dummy tape 1
The magnetic tape 24 formed by the overcoat layer 14, the magnetic material 22, and the base 11 is sequentially wound onto the take-up roll 25. This wound magnetic tape 2
The cross-sectional structure of No. 4 is as shown in FIG. That is, since the overcoat layer 14 is kept smooth while the magnetic material 22 is being dried by the smoothing roll 17,
When the magnetic material 22 is in a dry state, the unevenness due to the particle size of the magnetic material 22 appears on the upper surface of the overcoat layer 14, and all of it protrudes in the direction of the pinned layer 12. This is because it will be absorbed. The reason why the dummy tape 15 is attached to the overcoat layer 14 is that the overcoat layer 14 is an extremely thin film, so if it is brought into contact with the smooth roll 17 in that state, it will expand and contract, resulting in a uniform thickness. This is because the dummy tape 15 is used to supplement the strength of the dummy tape 15.

〔Effect of the invention〕

Since the present invention is configured as described above, the surface of the magnetic medium can be smoothed without forming an uneven surface on the surface of the overcoat layer due to the particles of the magnetic material. In addition, during the manufacturing process, the strength of the extremely thin overcoat layer is maintained by dummy tape, so even when applying the magnetic material to the dummy coat layer, the overcoat layer is supplied smoothly and there is no risk of cutting. The molded magnetic medium and the dummy tape can be easily separated by peeling off the dummy tape after the magnetic layer has dried.

As a result, an overcoat layer with extremely uniform thickness can be formed, and quality can be made uniform.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the structure of a conventional magnetic medium, FIG. 2 is a cross-sectional view showing the structure of a magnetic medium manufactured by the manufacturing method of the present invention, and FIG. 3 is a cross-sectional view showing the structure of a magnetic medium manufactured by the manufacturing method of the present invention. A sectional view showing the structure and FIG. 4 are explanatory diagrams showing the manufacturing process by the manufacturing method of the present invention. DESCRIPTION OF SYMBOLS 11... Base, 12... Fixed layer, 13... Magnetic layer, 14... Overcoat layer, 15... Dummy tape, 16... Protective tape. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A thin overcoat layer and a slightly thick dummy tape are brought into close contact with each other, and with the back of the dummy tape in contact with a smooth surface, a magnetic layer is applied to the back of the overcoat layer, and then a slightly thick dummy tape is applied. A method for producing a magnetic medium, comprising: attaching a base to the back surface of the magnetic layer, and peeling off the dummy tape from the overcoat layer after the overcoat layer, the magnetic layer, and the base are in close contact with each other.