JPH07105044B2 - Method of manufacturing magnetic recording medium - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetic recording medium having a ferromagnetic metal thin film suitable for high density magnetic recording as a magnetic recording layer.

2. Description of the Related Art In the field of magnetic recording, adoption of a new magnetic recording medium using a metal thin film as a magnetic recording layer is being considered in place of the conventional coating type magnetic recording medium in order to achieve high density.

Currently, the most common manufacturing method is to wind a polymer film along a cylindrical can,
Electron beam evaporation of -Ni, Co-Cr, etc. has been made to date by making many efforts such as improving the evaporation efficiency by interposing oxygen gas during the evaporation to obtain desired magnetic characteristics. These are improvements of oblique vapor deposition disclosed in Japanese Examined Patent Publication No. 41-19389, and are currently recognized as an indispensable medium for high density, and have a durable structure to satisfy good magnetic characteristics. There is a strong demand for the establishment of mass production technology for feasible media (IEEE Transactions on Magnetics).
on Magnetics) vol.MAG-21, No.-3, pp.1217-1220 (19
85)].

FIG. 2 is a vapor deposition used to carry out the method of manufacturing a magnetic recording medium proposed in order to further improve the vapor deposition efficiency when vapor depositing on a polymer film moving along a cylindrical can by a rotating belt. It is an example of an apparatus.

In FIG. 2, 1 is a polymer film, 2 is an endless rotary belt, 3 is a delivery shaft, 4 is a take-up shaft, and 5 is a first.
A cylindrical can, 6 is a second cylindrical can, 7 is a pressure roller,
8 is an evaporation source, 9 is an electron source, 10 is an accelerated electron beam, 11 is a vapor flow, 12 is a mask, 13 is a winding chamber, 14 is a vapor deposition chamber, 15 is a vacuum tank, 16 and 17 are exhaust systems, 18 Is a free roller and 19 is a vacuum wall.

The apparatus shown in FIG. 2 is advantageous not only in terms of vapor deposition efficiency but also in terms of space factor compared to using only a cylindrical can, so it can be said that this is definitely an important direction for future mass production technology. .

An advantage of vapor-depositing a polymer film while moving it along a carrier belt is high vapor-deposition efficiency as disclosed in Japanese Patent Laid-Open No. 54-13996 previously proposed by the present inventor.

Since then, proposals for improvements to the belt system have been made, and progress has been made steadily toward mass production [JP-A-58-1501].
35, 59-16524].

Problems to be Solved by the Invention However, in the above-mentioned one, since the temperature control of the carrier belt cannot be said to be sufficient because all the components including the winding system are configured inside the vacuum chamber, the modulation during high-density recording is difficult. Improvements have been desired in obtaining a large amount of noiseless media.

The present invention has been made in view of the above circumstances, and provides a manufacturing method capable of mass-producing a long medium with an excellent signal-to-noise level (hereinafter referred to as C / N).

Means for Solving the Problems In order to solve the above-mentioned problems, a method of manufacturing a magnetic recording medium according to the present invention comprises a ferromagnetic film on a polymer film electrostatically adsorbed on an endless belt rotating inside and outside a vacuum chamber. Is electron beam vapor deposition.

The magnetic recording medium manufacturing method of the present invention has the above-described structure, which allows the temperature of the endless belt to be precisely controlled, and therefore the temperature of the polymer film electrostatically adsorbed thereto can also be kept constant. Since it can be made microscopically uniform, it is possible to obtain a long magnetic recording medium with low noise and good C / N.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a configuration diagram of a main part of a vapor deposition apparatus used for carrying out the present invention.

In FIG. 1, 20 is an endless belt that rotates inside and outside the vacuum chamber 21, and the vacuum chamber 21 is divided into an upper chamber 22 and a lower chamber 23, and charged particle irradiation for electrostatically adsorbing a polymer film 24 to the endless belt. It is divided into room 25. 26 is a charged particle source,
It is selected from ion source, electron gun, etc. 27 is a charged beam, 28 is an unwinding shaft, 29 is a winding shaft, 30 is an evaporation source, 31 is a vapor flow, 32 is a gas introduction port, 33 is a gas introduction adjusting valve, 34 is a glow processing electrode, 35 is a nip A roller prevents the air from flowing into the vacuum chamber. 36 is a drive roller, 37 is a tension roller, 38 is a free roller, 39 is a cover, 40, 4
Reference numeral 1 is a vacuum exhaust system, and 42 is a cooling furnace for cooling the endless belt. The incident angle θ ₀ just above the evaporation source was set to 45 °, the emission angle α of the vapor flow was set to 36 °, and the electron beam evaporation was performed at the minimum incident angle of 20 °. Endless belt has a thickness of 24μ
m titanium foil was used.

A polyethylene terephthalate film with a thickness of 8 μm
The endless belt is irradiated with 10 Kev of Ar ions at 40 μA / cm ² to electrostatically adsorb and move the Co-Ni (Ni: 20 wt.
%) Was 0.13 μm electron beam evaporated in 5.3 × 10 ⁻⁵ Torr oxygen. The endless belt was cooled by blowing cold air of 5 ° C. at 14 m ³ / min, and was sent to the vapor deposition start part at 5 ° C.

For comparison, an endless belt of 24 μm titanium foil was placed in a vacuum chamber and rotated by two cans with a diameter of 20 cm cooled to 5 ° C. (system shown in FIG. 2 of the prior art). Co-Ni (Ni: 20wt%)
%) Was electron beam evaporated.

Commercially available 8 mm video (VX-801, manufactured by Matsushita Electric Industrial Co., Ltd.), which is a magnetic tape manufactured using a polymer film measuring 2500 m in length and 50 cm in width
Was modified, a ferrite head with a gap length of 0.1 μm was used, the center frequency was set to 6.6 MHz, and the C / N was compared. When 50 rolls were arbitrarily extracted and (1 roll 100m) C / N was investigated, the variation was within 0.6 dB within the measurement error in all of the 50 rolls, but in the comparative example, the variation was large, 3.7 There was a difference in C / N between dB maximum and minimum.

Effects of the Invention As described above, according to the present invention, there is an excellent effect that a magnetic recording medium having a good C / N can be uniformly manufactured over a large area.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of a vapor deposition apparatus used for carrying out the present invention, and FIG. 2 is a configuration diagram of a conventional vapor deposition apparatus. 20 ... Endless belt, 24 ... Polymer film, 26 ...
… Charged particle source, 30 …… Steam source, 42 …… Cooling furnace.

Claims (1)

[Claims] 1. A method of manufacturing a magnetic recording medium, characterized in that a ferromagnetic metal is electron beam vapor-deposited on a polymer film electrostatically adsorbed on an endless belt rotating inside and outside a vacuum chamber.