JPS5880135A - Method and device for production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To prevent the occurrence of cracks of a magnetic layer, by vapor- depositing a ferromagnetic material to a substrate among plural rotary cans while applying tension to said substrate. CONSTITUTION:A substrate 1 is shifted to a take-up shaft 15 from a feed shaft 14 in a vacuum tank 7 along plural rotary cans consisting of a rotary can 5 for formation of magnetic layer, a rotary can 6 for formation of protecting layer, etc. At the same time, a ferromagnetic material is vapor-deposited to the substrate 1 from an evaporating source 2 via a mask. In this case, for instance, a fulcrum 19 is connected to a roller which absorbs the fluctuation of peripheral speed between rotary cans via a lever 12. Thus tension is applied to the substrate 1 among the rotary cans.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for producing a magnetic recording medium in which the magnetic recording layer is a ferromagnetic layer deposited on a polymer molded substrate.

In magnetic recording, the value of using a ferromagnetic metal thin film as a magnetic recording layer for short wavelength recording is well known, and such media can also be produced using wet plating, vacuum evaporation, sputtering, and ion blating on a laboratory scale. However, some of them have been put into practical use for low-speed audio, and practical use for video is also on the horizon, and efforts are being made in various fields to solve various problems at the industrial level. .

In general, magnetic recording media often belong to one of several configurations shown in FIGS. 2(IL) to (d). Note that the back coat layer is not shown in the same figure. FIG. 26 is arranged on a substrate 24 and a ferromagnetic layer 26 is provided thereon. FIG. This figure shows a case where a multilayer structure is used, and FIG.
4 is shown.

Of course, other modifications such as arranging a protective layer on the ferromagnetic layer 26 (or 31) in Φ) or (0) in the figure are also possible.

An object of the present invention is to solve the problems that occur when manufacturing the magnetic recording media shown in FIGS. 2(t), 2(c), and 2(d) on an industrial scale.

Of course, even in the magnetic recording medium shown in FIG. 2 (IL), a similar problem occurs when the magnetic layer is formed by repeated vapor deposition and the surface is actively treated after vapor deposition. It is not important to select the configuration of the medium, but whether or not it is covered by the present invention depends on the manufacturing process adopted. When a protective layer is deposited after forming a thin film in a vacuum containing This was achieved as a result of detailed study and improvement of the problem of cracking in the magnetic layer, which occurs when the ferromagnetic layer is formed and then subjected to oxidation treatment on the surface, which occurs as a continuous process.

The present invention will be described in detail below using the drawings.

FIG. 1 shows an example of a vapor deposition apparatus according to the present invention.

Although FIG. 1 shows the case where there are two rotary cans, the concept is the same even when there are three or more rotary cans.

Also, in FIG. 1, the vacuum chamber 7. - is shown divided into three chambers, but it is not limited to this and can be further divided for glow treatment, but the present invention has been simplified to the extent that the basic requirements of the present invention can be explained in detail. O As shown in FIG. 1, the upper chamber 10 is mainly provided with a winding system, and the vapor deposition chamber is divided into 8 and 9. In this case, an example of a combination of electron beam evaporation and sputtering has been cited, but as mentioned above, the combination is not limited to this. The first can 6 and the evaporation source 2 are arranged opposite to each other, and the second can 6 is arranged opposite to the evaporation source 4.
9.8 are blown away by independent exhaust systems 13, 11.12, respectively.

The substrate 1 is rolled up from the feed shaft 14 via the first can 6 and the second can 6 onto the wind-up shaft 16 . 16 is a free roller, and the expander roller is not shown. A roller 17 is provided to absorb variations in circumferential speed between each can, and is connected to the fulcrum 19 by a lever, for example, so as to apply a constant tension to the film. Note that this configuration is just an example, and the rotation shaft of the roller 17 may simply be slid up and down. 3 is a mask for oblique vapor deposition, 20 and 21 are walls, and gas introduction parts and the like are not shown.

Note that the function of the roller 17 will be explained here. When winding is performed using a plurality of cans, there is almost no slippage between the substrate 1 and the cans because of the vacuum. On the other hand, the rotational speed of the rotating can is maintained constant by controlling the electric motor, but the reason why the circumferential speed variation is suppressed to about 0.2 yen or less is because the weight of the rotating can with a diameter of 1 m, for example, is kept constant. @600 The one used for film transport is 1.
This is obvious from the fact that it is close to the 000th floor.Also, the cause of circumferential speed variation is not due to one mechanical loss, and it is not possible to make the circumferential speed of each can exactly the same even if the same shape is finished. Therefore, for example, even if the relationship between the first can 6 and the second can 6 is made constant, the film will be displaced by the amount of the fluctuation described above. Cracks occur in the vapor deposited layer, which causes noise during short wavelength recording and must be prevented, but this can be completely prevented by absorption by the roller 17.

Next, the present invention will be explained in more detail.

[Example 1] Using the vapor deposition apparatus shown in FIG.
Polyethylene terephthalate film (reinforced stretched type, thickness 12μm, width 500s
) Oxygen is introduced from the outside at 0.21/, and the degree of vacuum is 3.
C obtained by electron beam heating at X 10-5 Torr
A ferromagnetic layer was formed by oblique deposition using a 10100% vapor flow at an incident angle of 40° or more. The film thickness was 0.2 mm. Next, 0.11% of town gas was introduced, and magnetron sputtering was performed using 8i and N4 as a target at I x 10' Torr to form a protective layer with a thickness of 0.02 μm.

What is the case where the weight of the roller 170 in Fig. 1 is set to 4 Ky? (The above steps were carried out using each of the conventional methods.
i14 s o Iv-te, 1st can 5 t 2nd
*The fluctuation of Kin6 is 0.16, ±0.22 respectively.
%Met.

The substrate on which the ferromagnetic layer and protective layer were formed as described above was heat-treated, the back surface of the substrate was coated with a resin to give it lubricity, and the magnetic tape manufactured by slitting it into 1/4-inch pieces was examined for noise. 0 As a result, the magnetic tape manufactured by the present invention achieved uniform and low noise over a length of 1000 m, whereas the magnetic tape manufactured by the conventional method achieved low noise within a length of 1000 m. There was a 180m region where the noise was -1i to edB high.

When we observed that area, we found that cracks had formed in a direction almost perpendicular to the direction of movement of the substrate. Since the occurrence position is not regular, it is necessary to inspect the entire length for practical use, but such an inspection cannot be performed in the actual process, so this tape cannot be used for practical use.

[Example 2] (io 90% Or
10 chips at an incident angle of 46° in a vacuum of lX1O-5 Torr.
As described above, ferromagnetic 1- was formed by oblique deposition to a thickness of 0.28 μm, and surface treatment was performed by high-frequency glow discharge at an oxygen partial pressure of 0.03 Torr along a can with a diameter of 5ooi+s. . The film winding speed is 26cm.
The circumferential speed fluctuations of the two cans were each ±0.21 yen. Comparison of noise similar to that in Example 1 over a length of 860 m of magnetic tape produced by applying a tension of 2 a Kg by the roller 17 to absorb fluctuations in circumferential speed and by bypassing the roller 17 using the conventional method. I did it.

As a result, it was found that 8 (I
There was a total area of 90 m in which the noise was high by B~12 dB, and an area where the noise was high by 3~5 dB was 140 m, whereas the one manufactured according to the present invention had uniform and low noise over the entire length. This reduces the weight of the roller 17 to 3q~7
There was no change even if the kg was changed.

[Example ♀]

After forming a permalloy layer with a thickness of 1 μm by electron beam evaporation on the polyimide film (thickness 26 μm) along the first rotating can (diameter 5 ooss), the roller 17
Apply a tension of 9~ to the second can (diameter soom)
A perpendicular recording medium was manufactured by forming a 0.0 asd Cr16 film to a thickness of 0.33 μm by electron beam evaporation with perpendicular incidence.

For comparison, roller 17 was manufactured as a vino-squeezing medium.

The case where the winding speed of the film was 10 seas to 30 seas and the circumferential speed fluctuation of each can was ±o, s % e ± 0.271 was investigated, but in the case of the film manufactured according to the present invention, the winding speed was 1300 m.
No cracks were observed in this area.

On the other hand, in the case of products manufactured using the conventional method, the total number of
A crack had formed for 70 meters. Even in perpendicular recording,
The noise caused by this crack has the disadvantage of reducing resolution, and the present invention is highly effective.

In addition, polyethylene terephthalate 6.6μm ~ 2t
μm thick, polyamide 3.8 μm to 9.7 μm thick, and polyimide 26 μm to 190 μm thick films were used as substrates.
Ni 20%, Coyo4 Ni251Cr5%
, Co95% Pt5%, Co95%W5%, etc. 0.1
Although it was formed according to the present invention to a thickness of .mu.m to 0.3 .mu.m, no cracks were similarly observed.

In the apparatus shown in FIG. 1, when the substrate moves from the feed shaft 14 to the winding shaft 16, 20% Co804Ni is obliquely evaporated at an incident angle of 70° or more in each can (0.06 μm thick in each can). and the same (,Co8
The magnetic tape obtained by electron beam evaporation of 0% Ni2O% at an incident angle of 700 or more and forming a magnetic layer with a total thickness of 0.2 μm on the substrate according to the present invention also showed no cracks and was uniform and uniform. Low noise was achieved.

The effect of the present invention on preventing cracks caused by the displacement of the film caused by the steep peripheral speed fluctuations was confirmed in many other examples as well. Exactly the same type of rodent was observed when the product was produced using an apparatus having three cans, two cans with a diameter of 5QQJll'' and one can with a diameter of 10001B.

As is clear from the above explanation, the medium obtained by the present invention is an excellent medium that does not impair the advantages of short wavelength recording.
The industrial value of the present invention is great.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a manufacturing apparatus according to the present invention. Figure 2 (IL), (b), (C), (d)
2A and 2B are cross-sectional views each showing an example of the structure of a magnetic recording medium. 1.22, 24, 27.32... Board, 2...
...Evaporation source, 3...Mask, 4...
・Spatter source, ramie. 6...Can, 7...Vacuum chamber, 14.
...Feeding shaft, 15... Winding up -,
16', 17... Laura. 31.33...Ferromagnetic layer. Figure 1 1, t

Claims (2)

[Claims] (1) When forming a ferromagnetic layer by vapor deposition on a polymer molded substrate that moves along a plurality of rotating cans arranged in series, tension is applied to the substrate between nine adjacent rotating cans. A method of manufacturing a magnetic recording medium, characterized in that: (2) A plurality of rotating rollers are arranged in series to move the polymer molded substrate on which a ferromagnetic layer is to be formed by vapor deposition along the circumferential surface, and between the adjacent rotating cans. An apparatus for manufacturing a magnetic recording medium, comprising means for applying tension to the substrate during movement.