JPH06231457A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide a magnetic recording medium capable of stably maintaining S/N with good reproducibility by setting the temp. of a rotating base higher as an incident angle is smaller at the time of depositing a ferromagnetic metal by evaporation with an electron beam onto a moving film. CONSTITUTION:The endless belt-shaped rotating base is formed of a stainless steel, titanium, etc., at 0.1 to 0.4mm thickness to <=0.2mum max. roughness. The high-polymer film 1 is unwound from a roller 3 and is taken up on a roller 4. Temp. control rollers 12, 13 which are set and controlled to the temp. lower at the roller 12 are provided. A tension roller 14 is provided as well. The side where the incident angle is smaller is so controlled as to be higher in the film forming temp. in the vapor deposition operation at the incident angle decreasing from the side where the angle is larger by the vapor deposition device constituted in such a manner. The temp. of the rotary supporting roller 13 is made higher than the temp. of the roller 12 as the incident angle is smaller at the time of vapor depositing the ferrromagnetic metal by vapor flow 8 on the film 1, by which the magnetic recording medium is obtd. with the good reproducibility.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art With the progress of information society, the amount of information to be recorded is remarkably increasing, and it is required to increase the recording density of magnetic recording as much as possible. Development of magnetic recording media has been brisk. Although many proposals have been made, the one currently put to practical use is a structure in which the surface of columnar fine particles is coated with an oxide of a ferromagnetic metal itself as disclosed in JP-A-53-58206. It has a well-balanced improvement in recording characteristics and durability, and its constituent elements consist of Co, Ni, and O (JP-A-56-15014), and these magnetic recording layers are formed by oxygen gas. C while intervening
A typical method is electron beam evaporation of o, Co-Ni, and there are some proposals for introducing oxygen, but in the vicinity of the substrate,
A position close to the part for controlling the incident angle is often used (Japanese Patent Laid-Open No. 54-19199, Japanese Patent Laid-Open No. 58-322).
34 publication).

A conventional method of manufacturing a magnetic recording medium will be described below. FIG. 3 is a configuration diagram of a main part of a vapor deposition apparatus used for manufacturing a conventional magnetic recording medium.

In FIG. 3, 1 is a polymer film such as polyester, 2 is a rotary support controlled to a constant temperature, 3 is a film feeding shaft, 4 is a film winding shaft, 5 is an evaporation source container, and 6 Is a vapor deposition material, 7 is an accelerated electron beam, 8 is a vapor flow, 9 is a mask, and 10 is an oxygen introduction nozzle. Figure 3
The method of manufacturing the magnetic recording medium by using the mounting described below is as follows.

For example, polyethylene terephthalate, polyethylene naphthalate or the like having a granular surface is set in a winding system, evacuated, and a vapor deposition material such as Co or Co-Ni is heated and evaporated by an accelerating electron beam to form a tangent line. Deposition is completed at an incident angle (referred to as the minimum incident angle) that advances the vapor deposition from the direction and is blocked by a mask, at which time oxygen gas is introduced near the minimum incident angle to form a magnetic recording layer consisting of a partial oxide film. Is carried out on a film moving along a rotary support.

[0006]

However, although the coercive force increases with an increase in the amount of oxygen introduced in the above-mentioned conventional structure, the saturation magnetic flux density decreases and S obtained with an optimum amount of introduction.
There is a problem that the maximum value of the / N ratio is lower than the value required for higher density recording, and only a medium having an insufficient balance between durability and S / N ratio can be manufactured.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a method for manufacturing a thin magnetic recording medium having both durability and high output characteristics, which enables narrow track high density recording. And

[0008]

In order to achieve this object, a method of manufacturing a magnetic recording medium according to the present invention includes a method of rotating a support as an incident angle becomes smaller, when a ferromagnetic metal is electron beam evaporated on a moving film. It is to make the body temperature higher.

[0009]

With this structure, the tendency of the deposition rate to increase and the defects to increase as the incident angle becomes smaller is suppressed by the temperature rise, the crystallinity is improved, the density is excellent and the durability is excellent. Since the improvement of the uniformity of the structure leads to the improvement of noise, both the durability and the high density recording characteristic can be improved.

[0010]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the same components as those in FIG. 3 are designated by the same reference numerals. Reference numeral 11 denotes an endless belt-shaped rotary support, which includes stainless steel, titanium, molybdenum,
It is preferable that the metal foil of copper-titanium alloy or the like has a thickness of 0.1 to 0.4 mm and the surface roughness is 0.2 μm or less in terms of maximum roughness. 12, 1
3 is a temperature adjusting roller, and the number thereof is not limited to two. 12 and 13 are temperature controlled, 12 is 1
It is configured so that the temperature is controlled to be lower than 3. 14
Is a tension roller. With the vapor deposition device having this configuration, the film forming temperature can be increased as the incident angle becomes smaller in vapor deposition in which the incident angle changes from the larger side to the smaller side. The polymer film is preferably brought into close contact with the belt surface by electrostatic attraction by injecting electrons into the film.

In order to further clarify the effect of this embodiment, a magnetic recording medium will be concretely manufactured as a prototype and the results of characteristics comparison with those obtained by the conventional method will be described in detail.

The thickness is 6.3 μm, the Young's modulus is 540,590 [Kg / mm ² ] in the longitudinal direction and the width direction, and the average roughness is 3
0Å polyethylene naphthalate film (diameter 150
Å SiO ₂ ultrafine particles with an average density of 20 particles / μm ² resin-fixed coating layer was used in advance) was used to make a stainless steel endless belt with a circumference of 2.3 m and a thickness of 0.2 mm (maximum roughness). : 0.07 μm) by adjusting the temperature of the temperature adjusting roller 12 having a diameter of 40 cm and the temperature adjusting roller 13 having a diameter of 20 cm, and the conventional example is wound along a rotary can having a diameter of 1 m which is adjusted to 20 ° C. and 60 ° C. While taking it, Co was electron-beam evaporated to form a magnetic layer of 0.18 μm. The incident angle was 90 degrees to the minimum incident angle of 46 degrees, and oxygen gas was introduced from the inside of the mask that regulates the minimum incident angle, and the film was formed under the condition that the magnetic characteristics were almost the same. A hard carbon film was deposited on each magnetic layer by a plasma CVD method in which methane was ionized to form a carbon film. Perfluoropolyether as a lubricant was further placed on the carbon film by a 40 Å solution coating method, a back coat layer was formed to 0.45 μm, and a magnetic tape having a width of 8 mm was experimentally manufactured and the characteristics were compared. The characteristics of the magnetic tapes are compared with each other by modifying the high-band 8 mm video deck and recording S / N at a recording wavelength of 0.47 μm and a track pitch of 9 μm.
A relative comparison of the ratios was made. The length of the magnetic tape was 100 m, 5 rolls were randomly selected, and the average value of 5 rolls was displayed. Still characteristics are 40 after increasing the tension to 25g.
The comparison was made at 5 ° C and 5% RH. The characteristics of the magnetic recording medium according to this example and the characteristics of the magnetic recording medium of the comparative example are shown in comparison with each other (Table 1).

[0014]

[Table 1]

As is clear from (Table 1), the magnetic recording medium manufactured according to the present example has an excellent effect that it is possible to realize durability and high S / N ratio in high density recording in narrow track recording. Is obtained.

As described above, according to the manufacturing method of this embodiment, when the ferromagnetic metal is electron beam evaporated on the moving film, the temperature of the rotating support becomes higher as the incident angle becomes smaller, so that the narrow track is narrowed. It is possible to obtain a large number of magnetic recording media with excellent reproducibility and capable of stably maintaining an excellent S / N ratio even after repeated use.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a configuration diagram of essential parts of a magnetic recording medium manufacturing apparatus for carrying out the method of manufacturing a magnetic recording medium according to the second embodiment of the present invention. In FIG. 2, the same components as those in FIG. 1 are given the same numbers. Reference numerals 15, 16 and 17 are temperature adjusting rollers, 18 is a second mask, 19 is a second oxygen gas introduction nozzle, 20 is a vapor flow A, and 21 is a vapor flow B.

The present invention was implemented by the apparatus having the above-mentioned configuration. The present invention will be specifically described in detail by comparing the magnetism of an actually manufactured magnetic recording medium with a conventional example and a comparative example.

SiO ₂ having an average particle diameter of 200 Å has an average density of 50 particles / μ ^{2 on} a polyimide film having a thickness of 6 μm (average roughness 20 Å, Young's modulus length 600, width 650 kg / mm ² ).
After coating and fixing with, the Co-O oblique deposition film and Co under the following conditions.
A laminated film of -O perpendicular magnetization films was formed. Co is evaporated and heated by an accelerating electron beam in a magnesia container, vapor deposition with an incident angle in the range of 90 to 65 degrees, and 40 to 20 degrees.
Deposition was continued. Oxygen was introduced simultaneously from the nozzle 10 and the nozzle 19. Temperature control rollers 15,1
Adjust the inclination angle of the belt by changing the positional relationship of 6, 17
The film thicknesses at 90 to 65 degrees and 40 to 20 degrees were adjusted in association with the amount of oxygen introduced to form a magnetic layer having apparent magnetic characteristics almost the same as those of the conventional example. On the other hand, in the conventional example, a film is moved along a rotary can (temperature -10 ° C.) having a diameter of 1 m at 90 to 65 ° and 40 to 20 °, and oxygen gas is also deposited from a 65 ° regulated portion and a 20 ° regulated portion. Introduced. The adjusted temperatures of 15, 16 and 17 are -25, respectively.
℃, 0 ℃, 20 ℃ (2a), 160 ℃, 1
Two levels were performed at 00 ° C and 20 ° C (2b).
On each of the laminated magnetic films, a diamond-like hard carbon film is formed by plasma CVD to 70 Å, perfluoroarachidic acid is arranged on 30 Å, a back coat layer of 0.5 μm is arranged and a magnetic tape of 8 mm width each Processed into. By using an 8 mm video modified from these tapes, digital recording with a 5 μ track and a bit length of 0.2 μ was performed and relative error rates were compared. As for durability, 5 ° C, 85% R
The error rate after adding 100 pass history with H was evaluated.

The characteristics of the magnetic recording medium according to this example and the characteristics of the conventional magnetic recording medium are shown in comparison with each other (Table 2).

[0021]

[Table 2]

As is clear from (Table 2), the magnetic recording medium manufactured according to this example has an excellent effect that high-density digital recording can be performed under a narrow track condition with a good error rate. is there.

As described above, according to this embodiment, when the ferromagnetic metal is electron beam evaporated on the moving film, the in-plane magnetized film and the magnetized film with the easy axis of magnetization rising along the belt-shaped rotary support. By forming them continuously, the thickness distribution of the in-plane magnetized film and the film with the easy axis of magnetization raised is optimized, the output increases due to the effect of the in-plane magnetized film becoming a magnetic flux path, and noise reduction. And a high saturation magnetic flux density can both be achieved, and an appropriate surface oxide film is formed in a region where the saturation magnetic flux density is high, so that the balance between high recording density characteristics and durability reliability can be significantly improved.

[0024]

As described above, according to the present invention, when a ferromagnetic metal is electron beam evaporated on a moving film, the temperature of the rotary support becomes higher as the incident angle becomes smaller, thereby narrowing the track. Excellent S / N with high density recording
It is possible to reproducibly obtain a large amount of magnetic recording media that can stably maintain the ratio even after repeated use.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a main part of a vapor deposition apparatus used for manufacturing a magnetic recording medium according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of an essential part of a vapor deposition device used for manufacturing a magnetic recording medium according to a second embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view of a main part of a vapor deposition apparatus used for manufacturing a conventional magnetic recording medium.

[Explanation of symbols]

 1 Polymer Film 6 Deposition Material 11 Rotating Support (Endless Belt) 12 Temperature Adjusting Roller 13 Temperature Adjusting Roller 15 Temperature Adjusting Roller 16 Temperature Adjusting Roller 17 Temperature Adjusting Roller 18 Second Mask

Claims (2)

[Claims] 1. A method of manufacturing a magnetic recording medium, characterized in that, when a ferromagnetic metal is electron-beam evaporated on a moving film, the temperature of a rotary support becomes higher as the incident angle becomes smaller. 2. An in-plane magnetized film and a magnetized film with an axis of easy magnetization rising are continuously formed along a belt-shaped rotary support when a ferromagnetic metal is electron beam evaporated on a moving film. And a method for manufacturing a magnetic recording medium.