JPH0352134B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention enables the surface of an overcoat layer that contacts a magnetic head to be formed to be extremely smooth.
The present invention relates to a method of manufacturing a magnetic medium that is easy to manufacture.

[Conventional technology]

Traditionally, magnetic materials are coated on the base, such as magnetic tape, magnetic floppies, magnetic cards, etc.
Magnetic media, in which various information is magnetically stored in this 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 the magnetic head is brought into direct contact with magnetic material, the particles of the magnetic material will wear out the magnetic head.
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 instead of barium ferrite as a material and utilizing its 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 barium ferrite, strontium ferrite has the problem that the size of the magnetic particles is unstable when applied to the base, and the shape of the particles becomes large. Even if an overcoat layer was attached to the surface, irregularities often occurred.

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. The magnetic layer 2 is coated and fixed,
An extremely thin overcoat layer 3 is applied to 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 will be exposed on the surface of the overcoat layer 3. Therefore, the overcoat layer 3 itself has irregularities. For this reason, when a magnetic head is brought into contact with and slid on the overcoat layer 3, the magnetic head is worn out, making it impossible to write or read information stably over a long period of time. In order to prevent this drawback, the surface of the overcoat layer 3 is sometimes polished and smoothed in the manufacturing process of magnetic media, but there are limits to the smoothing work, and The coater device for the overcoat layer 3 wears out quickly, leaving various problems.

In order to reduce the unevenness on the surface of this magnetic medium,
A thin overcoat layer is brought into contact with a smooth surface in advance, a magnetic layer is applied to the back side of the overcoat layer in this state, and then a slightly thick base is attached to the back side of the magnetic layer to form an overcoat layer. A manufacturing method has also been devised in which no unevenness caused by the magnetic material is exposed on the surface side of the coat 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 thinned due to fluctuations in tensile force. This had the disadvantage that a phenomenon in which the thickness changed occurred.

[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. Attach a slightly thick base to the back surface of the magnetic layer,
The present invention provides a method for manufacturing a magnetic medium, which features the step of peeling off the dummy tape from the overcoat layer after the overcoat layer, magnetic layer, and base are brought into close contact with each other.

[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, and then a base is applied to the back side of the magnetic material. By bringing the three layers into close contact with each other to form three layers, and then peeling off the dummy tape from the overcoat layer after the magnetic layer has solidified, it is possible to produce 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 this 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 The dummy tape 14 and the dummy tape 15 are supplied together, and are in a state where they can be easily peeled off in later processing. In this state, it can be considered that the load such as tension is maintained by the strength of the dummy tape 15, and the overcoat layer 14 is 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. And the above-mentioned protective tape 1
The protective tape 16 is pulled out from one end of the supply roll 18 on which the tape 6 is wound, and its back side (with the dummy tape 15 side as the back side) is in close contact with the surface of the smooth roll 17, and only the dummy tape 15 is separated. It is wound up on a collection roll 19.
A nozzle 21 of a hopper 20 is brought close to the surface of the protective tape 16 (toward the overcoat layer 14), and a magnetic material 22 is stored in the hopper 20 in a liquid state. A slightly thick base 11 made of polyethylene or the like is wound around the base roll 23, and this base 11 is in close contact with the smooth roll 17 at a slightly lower surface thereof, and the overcoat layer 14 and the base 11 The formed magnetic tape 24 is wound in the direction of the take-up roll 25.

In this configuration, the protective tape 16 sequentially drawn out from the supply roll 18 is wound around the outer circumferential surface of the smooth roll 17, and rolls on the outer circumference of the smooth roll 17 while keeping the surface flat. During this rolling, the magnetic material 22 housed in the hopper 20 is sprayed thinly from the nozzle 21 and coated on the surface of the overcoat layer 14. When the base 11 is dried to a certain extent, the base 11 unwound from the base roll 23 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 overcoat layer 14 The dummy tape 15 is peeled off and the dummy tape 15 is removed.
and magnetic head 24 are separated below smooth roll 17. Then, the dummy tape 15 is taken up and collected by the collection roll 19, and the magnetic tape 24 formed by the overcoat layer 14, the magnetic material 22, and the base 11 is taken up and collected by the collection roll 19.
It will be wound up in sequence. The cross-sectional structure of the wound magnetic tape 24 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, the overcoat layer 14 is kept smooth while the magnetic material 22 is being dried.
When the magnetic material 22 is in a dry state, the unevenness due to the particle size of the magnetic material 22 does not appear on the upper surface of the overcoat layer 14, but all protrude in the direction of the fixed layer 12, and the fixed layer 12 absorbs all the unevenness. This is because it will be done. 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. During the manufacturing process, the strength of the extremely thin overcoat layer is maintained by the dummy tape, so even when applying the magnetic material to the dummy coat layer, the overcoat layer is smoothly supplied and cut, etc. The molded magnetic medium and the dummy tape can be easily separated by peeling off the dummy tape after the magnetic layer is 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.

Claims (1)

[Claims] 1. Place a thin overcoat layer and a slightly thick dummy tape in close contact with each other, apply a magnetic layer to the back of the overcoat layer with the back of the dummy tape in contact with a smooth surface, and then apply a slightly thick dummy tape. A method of manufacturing a magnetic medium, comprising: attaching a thick base to the back surface of the magnetic layer, and peeling off the dummy tape from the overcoat layer after the overcoat layer, magnetic layer, and base are in close contact with each other.