JPH03295032A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To prevent the generation of winding wrinkles in spite of the presence of step at both side ends of a vapor deposited film by depositing a magnetic material by evaporation in such a manner that the width of the vapor deposited part attains >=90% of the width of a web-like base. CONSTITUTION:The web-like base 4 is partially suspended on the peripheral surface of a main drum 2 acting as a cooling can and a mask 6 is provided apart a specified spacing d opposite to the part where the base is suspended. The width Wm of the aperture 6a of this mask 6 is specified to >=90% of the width Wb of the base 4. The evaporated magnetic material in a crucible 8 is deposited by evaporation on the base 4 in the range limited by the size of the aperture 6a of the mask 6 and, therefore, the width of the vapor deposited film is >=90% the width Wb of the base 4. The width of the vapor deposited film is required to be >=90% of the width Wb of the base 4. The step generated between the vapor deposited part and the non-vapor deposited film is the cause for generating the winding wrinkles if the width is smaller than this range.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for depositing magnetic recording material onto a web-like support.

(Prior Art) In the production of magnetic tapes, a method is known in which a metallic magnetic material is deposited on a web-shaped polymer film support to form a thin magnetic recording layer.

In this process, a wide web-like support, which is later sliced into a tape shape, is suspended and transported on a rotating drum, and material evaporated from a deposition source consisting of molten metal in a crucible is evaporated in a vacuum onto the support. In this case, a mask is placed near the surface of the drum, and the vapor deposition material is vapor-deposited onto the support through this mask.

This is because, without a mask, vapor deposition would occur at the end of the drum where no support is suspended, and the vapor deposition material would damage the drum surface.

(Problem to be Solved by the Invention) The mask has a width (here, "width" refers to the length measured parallel to the axis of the drum) that is smaller than the width of the support, and the mask is The vapor deposited layer on the support is formed inward from a portion several layers to several tens of meters away from the edge (side edge) in the width direction of the support.

Therefore, the support has a vapor-deposited portion made of a vapor-deposited film of a constant thickness over substantially the entire width, and has undeposited portions on both side edges where no vapor deposition is performed. For this reason, when the support leaves the drum and reaches the next exit roll after vapor deposition, wrinkles occur near the boundary between the vapor-deposited part and the undeposited part of the support, and these wrinkles do not disappear during transportation until winding. This may cause wrinkles in the wrapping and cause product defects.

Therefore, it is an object of the present invention to provide a method for manufacturing a magnetic recording medium that does not cause such winding wrinkles.

(Means for Solving the Problems) The present invention is characterized in that the vapor deposition is performed so that the width of the vapor deposition portion is 90% or more of the width of the support.

That is, the method for manufacturing a magnetic recording medium according to the present invention includes depositing a magnetic recording material on a web-like support conveyed on a drum to form a deposited film on the support. The vapor deposition is performed so that the width of the vapor-deposited film is 90% or more of the width of the web-like support.

(Functions and Effects) In the method for manufacturing a magnetic recording medium according to the present invention, the width of the vapor deposited film is set to 90% or more of the width of the support as described above, so even if there are steps at both ends of the vapor deposited film, the web This eliminates the formation of large wrinkles on the product, eliminating the aforementioned cause of product defects.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an example of a device for carrying out the method according to the invention. Main drum 2 acts as a cooling can
A web-like support 4 is partially suspended on the circumferential surface of the web-like support 4, and a mask 6 is provided at a constant interval d in opposition to the suspended portion.

This mask 6 has a rectangular opening 6a, and the width WIl of this opening 6a is smaller than the width Wd of the drum 2. The width Wd of the web-like support 4 is the width Wd of the drum 2.
smaller. The width WIIl of the opening 6a of the mask 6 is
It is 90% or more of the width wb of the support 4. A crucible 8 is placed below this mask 6 as an evaporation source for the magnetic material. This crucible 8 has a width sufficient to cover the width of the opening 8a of the mask 6.

The magnetic material in the crucible 8 is scanned with an electron beam,
This melts and vaporizes the magnetic material. The evaporated material fills the opening 6 of the mask 6, as shown by the dashed line in FIG.
Since the vapor deposition is performed on the support 4 within a range limited by the size of a, the width W of the vapor deposited film 10 is limited as shown in FIG.
a is 90% or more of the width wb of the support 4.

In the case of this type of thin film magnetic tape, the width Wa of the vapor deposited film 10 must be at least 90% of the width wb of the support 4. If it is smaller than this, a step 10a will be formed between the vapor deposited area and the non-evaporated area. This causes the above-mentioned curling wrinkles.

In addition, in the conventional method, the ratio of the vapor deposition film width Wa to the support width wb was 80 to 8596.

Specifically, based on the above method, an apparatus was constructed under the following conditions, and the experiment was carried out.

Ultimate vacuum 2. OXIO°' Torr
Evaporation vacuum degree 6. OX 10” Torr
Conveyance speed 100771/min Support width (Wb) 500 mm Mask opening width (W
m) 480 mtn mask and tram distance
5 mtn electron gun output 70'! ×2
Vapor deposition film thickness: 2000 people Vapor deposition material: Co Ni O Support thickness
10 μm When an experiment was conducted with these specifications, a vapor deposited film having side edges approximately 10 m inside the side edge of the support was well formed.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the method for manufacturing a magnetic recording medium of the present invention, FIG. 2 is a partially cutaway elevational view showing an enlarged part of the method, and FIG. FIG. 4 is a plan view showing a part of the web-like support that has been deposited, and FIG. 4 is a cross-sectional view showing a further enlarged part of the web-like support. 2... Rotating drum (cooling can) 4... Web-like support 6... Mask 6a...
Opening of mask 8... Crucible 10... Vapor deposited film
10a... Vapor deposition main part iob... Vapor deposition edge Wa... Vapor deposited film width wb... Web-like support width

Claims (1)

[Claims] 1) A method for manufacturing a magnetic recording medium in which a deposited film is formed on the support by depositing a magnetic recording material on a web-like support that is conveyed on a drum, wherein the width of the deposited film is equal to or smaller than the width of the web-like support. A method for manufacturing a magnetic recording medium, characterized in that the vapor deposition is performed so that the width is 90% or more of the width of the magnetic recording medium.