JPH09212862A - Apparatus for production of vapor deposition type magnetic tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen the occurrence of curving (cupping) in the transverse direction of a magnetic tape and to reduce the production cost by providing a cooling drum with curvature in such a manner that its central part bulges in its height direction. SOLUTION: The tape substrate surface 5a of particularly the cooling drum 5 of this apparatus for production is formed into a circular arc surface or arced surface bulging at the center and is formed into a drum shape as a whole. When the measurement on the cupping is carried out, it is understood that the cupping is less with the drum shape of the cooling drum 5 than with the cylindrical shape thereof. The cupping is smaller as the radius W of curvature is smaller. Particularly if the radius W of curvature of the drum shape is <=1M, the tape is wrinkled at the time of vapor deposition and the vapor deposition in not possible with such tape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor deposition type magnetic tape manufacturing apparatus for forming a magnetic layer comprising a metal vapor deposition type magnetic thin film on a base film comprising a non-magnetic support.

[0002]

2. Description of the Related Art In the field of magnetic recording such as video tape recorders, there is a strong demand for higher density in order to achieve high image quality, and the magnetic recording medium used for this is pure metal or CoNi. A magnetic material made of an alloy such as is suitable, and is deposited on a non-magnetic support by a plating method or a vacuum thin film forming method (vacuum evaporation method, sputtering method, ion plating method, etc.) to form a magnetic layer. A so-called metal thin film type magnetic recording medium to be formed has been put into practical use.

The magnetic recording medium of the metal magnetic thin film type is excellent not only in coercive force, squareness ratio and electromagnetic conversion characteristics in a short wavelength region, but also because the magnetic layer can be made thinner, the packing density of the magnetic material is increased. It has a number of advantages, such as being able to increase

Among them, the vapor deposition tape for forming the magnetic layer by the vacuum vapor deposition method has already been applied to commercial products in the market because of its high production efficiency and stable characteristics.

As a problem in manufacturing the vapor-deposited tape, the tape is curved in the width direction, so-called cupping.
Is likely to occur. When cupping is big,
During running of the magnetic tape in the VTR, troubles such as one-sided contact of the magnetic tape and breaking of the edge of the magnetic tape are likely to occur, and it is desirable that the cupping be as small as possible.

PET (polyethylene terephthalate) or the like is usually used as the non-magnetic support for vapor deposition in view of manufacturing cost and performance. Since high heat is applied to the non-magnetic support during vapor deposition, in order to avoid melting of the non-magnetic support due to this high heat, a non-magnetic material is applied to the cylindrical cooling drum (cooling can) cooled to about -20 ° C. The vapor deposition is carried out by closely contacting the permeable support. For this reason, high heat is applied to the vapor deposition surface side of the non-magnetic support due to the deposition of metal vapor, while heat is not transmitted because the opposite surface is in close contact with the cooling can, and the non-magnetic support has its thickness direction. A large temperature gradient occurs in the. PE
The T base contracts after thermal expansion to generate internal stress, which causes cupping. If the cupping is extremely large, the above-mentioned problem in practical characteristics arises, and a heat treatment in a post process is necessary, which is a factor of increasing the manufacturing cost.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vapor deposition type magnetic tape manufacturing apparatus in which the widthwise bending (cupping) of the magnetic tape is less likely to occur.

[0008]

A vapor deposition type magnetic tape manufacturing apparatus of the present invention is provided with a cooling drum for supporting a base film, and vapor of metal particles is deposited on the base film supported by the cooling drum to manufacture a magnetic tape. In the vapor deposition type magnetic tape manufacturing apparatus, the vapor deposition type magnetic tape manufacturing apparatus is characterized in that it has a curvature such that the central portion bulges in the height direction of the cooling drum. Was made smaller.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.
~ It will be described with reference to FIG. 1 is a schematic side sectional view of a vapor deposition type magnetic tape manufacturing apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic perspective view of a cooling drum used in the vapor deposition type magnetic tape manufacturing apparatus. In these figures, first, a crucible 3 having a lump of cobalt, which is a vapor deposition material, is provided inside a housing 1 in which a vacuum chamber 2 is formed by evacuating to about 10 ^-2 [Pa], and an electron provided outside the housing 1. The electron beam 4a is generated from the gun 4, and the vapor deposition material in the crucible 3 is irradiated with the electron beam 4a via the deflecting device 4b, and the vapor is melted to generate the vapor 3a of metal particles in the housing 1. Has been done.

Above the crucible 3, there is provided a cooling drum 5 which rotates around a horizontally arranged shaft 5c and supports the base film 8a. Outside the cooling drum 5, a pair of upper and lower cooling drums 5 are provided. The supply roller 6a and the take-up roller 6b are arranged, and a base film 8a made of a non-magnetic material such as PET is wound around the supply roller 6a so as to rotate freely. The take-up roller 6b
Is provided with a driving device (not shown), and is formed so that the vapor-deposited magnetic tape 8b is wound up.

A guide roller 7a is provided between the supply roller 6a and the cooling drum 5 for determining the winding angle of the base film 8a on the surface of the cooling drum 5 and for removing the slack, and the winding roller 6b. A guide roller 7b having the same purpose is arranged between the cooling drum 5 and the cooling drum 5.

A shield plate 9 having an opening 9b at the upper portion of the crucible 3 and in the vicinity of the cooling drum 5 is provided.
a is provided. An oxygen gas introducing pipe 10 for supplying oxygen is also provided at the position of the opening 9b.

The present invention is particularly characterized in that the tape supporting surface 5a of the cooling drum 5 has an arcuate surface or an arcuate surface with a bulged center, and has a drum shape as a whole.

Next, the experimental results of the vapor deposition type magnetic tape manufacturing apparatus of the present invention will be described. At this time, in addition to the conventional cylindrical cooling drum, a drum-shaped cooling drum 5 having five kinds of curvatures in the height H direction of the cylinder was prepared and vapor deposition was performed on each drum. The diameter D of the cooling drums 5 was unified to 1 m at the maximum. When the drum-shaped cooling drum 5 is used, the guide rollers 7a, 7b immediately before and after the cooling drum 5 are also provided with a certain degree of curvature so that the center portion bulges in the height direction, so that the base Film 8
It was possible to run without causing wrinkles in a.

The incident angle of vapor deposition is 90 ° to 45 ° from the normal direction of the base film 8a, the feed rate of the base film is 25 m / min, and the vapor deposition layer has a thickness of 200 nm.
Vapor deposition was performed so that Further, during the vapor deposition, film formation was carried out while introducing oxygen gas at a rate of 500 cc / min from the oxygen gas introducing pipe 10.

After depositing the vapor-deposited layer in this manner, the sample was completed through post-processes such as backcoating, rust prevention treatment, lubricant application, slitting (cutting), and cupping was measured.

The cupping was measured by measuring the difference in height between the center and the end of the tape when the tape cut into 8 mm width was horizontally fixed with the back surface facing upward by applying 1 g of tension in the length direction. Is expressed in mm. When the center of the tape is high, cupping is defined as positive, and when the edge is higher, cupping is defined as negative. The measurement was performed with a cupping measuring instrument that was a combination of a tape fixing table and an optical microscope. With a running characteristic of 8 mm VTR, cupping is -0.
It has been found that a range of 5 mm to +0.5 mm is desirable.

Table 1 shows the shape and size of the cooling drum used for vapor deposition and the measurement results of cupping of the prepared sample. It can be seen from Table 1 that cupping is smaller when the cooling drum 5 has a drum shape than a cylindrical shape. It can be seen that as the radius of curvature W becomes smaller, the cupping becomes smaller, and especially when the radius of curvature W of the drum shape is 50 m or less, the cupping becomes sharply small and a good tape can be formed. However, when the radius of curvature W was 1 m or less, wrinkles were formed on the tape during vapor deposition, and vapor deposition was not possible.

[0019]

[Table 1]

Accordingly, the radius of curvature W of the drum shape of the cooling drum
Is preferably 5 m to 50 m. In the present embodiment, the Co film is formed as the vapor deposition layer, but in addition to Co, metals such as Fe and Ni, Co—Ni-based alloys, Co—Ni—Pt-based alloys, and Fe.
-Co-Ni type alloy, Fe-Ni-B type alloy, Fe-C
In-plane magnetization recording metal magnetic film made of o-B alloy, Fe-Co-Ni-B alloy, Co-Cr alloy thin film, Co
It is also very effective in the case of perpendicular magnetic recording metal magnetic thin film such as -O thin film.

[0021]

As is apparent from the above description, according to the present invention, it is possible to provide a vapor deposition type magnetic tape manufacturing apparatus capable of manufacturing a vapor deposition tape with small cupping.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view of a vapor deposition type magnetic tape manufacturing apparatus of the present invention.

FIG. 2 is a perspective view of a cooling drum used in the vapor deposition type magnetic tape manufacturing apparatus of the present invention.

[Explanation of symbols]

 1 Housing 2 Vacuum Chamber 3 Crucible 4a Electron Beam 4b Deflection Device 5 Cooling Drum 5a Film Support Surface 6a Supply Roller 6b Winding Roller 7a, 7b Guide Roller 8a Base Film 8b Magnetic Tape 9a Shield Plate 9b Opening 10 Oxygen Gas Introducing Tube H High W radius of curvature D maximum diameter

Claims (3)

[Claims] 1. A vapor deposition type magnetic tape production apparatus for producing a magnetic tape by providing a cooling drum for supporting a base film and vapor-depositing vapor of metal particles on the base film supported by the cooling drum. A vapor deposition type magnetic tape manufacturing apparatus characterized by having a curvature such that the central portion bulges in the height direction. 2. The vapor-deposited magnetic tape manufacturing apparatus according to claim 1, wherein the radius of curvature of the cooling drum in the height direction is 5 m to 50 m. 3. The vapor-deposited magnetic tape manufacturing apparatus according to claim 1, wherein guide rollers are arranged in front of and behind the cooling drum, and a curvature is provided such that a central portion bulges in a height direction of the guide roller. A vapor deposition type magnetic tape manufacturing apparatus characterized by the above.