JPH05198056A - Cylinder for magnetic recording device and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a small and lightweight cylinder used in a small and lightweight magnetic recording device. [Structure] The material of the cylinder 1 is made of resin, and the surface thereof is coated with a diamond-like carbon film 2. According to this configuration, the weight of the cylinder can be reduced, and the durability of the cylinder and the lubricity with the tape can be dramatically improved, so that low tension running can be performed, and the magnetic recording device can be reduced in size and weight. is there.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder used in a magnetic recording device such as a video cassette recorder.

[0002]

2. Description of the Related Art In recent years, magnetic tape recorders and other magnetic recording devices have been reduced in size and weight, and along with this, reductions in size and weight of mechanical parts constituting mechanisms have been studied. Among the components, the cylinder has a large volume and weight in the mechanism,
It is desired to reduce the diameter and weight of the cylinder.

Usually, the cylinder is made of aluminum, which is relatively light among metals, and is composed of a rotating upper cylinder and a fixed lower cylinder. A magnetic head for recording / reproducing is mounted on the upper cylinder side, and by rotating this, the magnetic head performs recording / reproducing. Hereinafter, the operation of the cylinder during recording and reproduction will be described in detail with reference to FIG.

A magnetic tape 13 for recording signals is shown in FIG.
It is assumed that the vehicle is traveling in the direction (a) shown in. The magnetic tape 13 is wound around the cylinder 1 with an inclination as shown in FIG. In this state, when the upper cylinder 11 is rotated at a high speed in the direction of (a) in the figure, the magnetic head 14 draws a scanning locus on the magnetic tape 13 as shown by the broken line in (b). As a result, a large number of signal recording areas (tracks) shown in FIG. 5C are formed on the magnetic tape. By such a principle, it becomes possible to record a high-density video signal on a limited magnetic surface. The magnetic head 14 usually starts recording one track at the same time as the next head starts recording another track.
In the reproducing operation, the signal recorded on the magnetic tape 13 is read by the same principle.

On the other hand, the lower cylinder 12 is fixed without rotating. A tape guide 15 is provided on the surface according to a predetermined angle, and the magnetic tape 13 runs along this guide, so that the tape can always be in a normal position for recording and reproduction.

[0006]

However, if the cylinder is made smaller and lighter while maintaining these precisions, the following problems occur.

Since the cylinder is in contact with the magnetic surface of the tape while rotating at a very high speed, the surface of the cylinder is always in a severe sliding state. If the diameter of the cylinder is further reduced in this situation, the air film formed between the tape and the cylinder is further reduced, and the sliding state becomes more severe. As a result, the tape or cylinder surface wears and causes many problems.

In particular, when a metal-deposited tape for high density recording is used as the recording tape, both the cylinder and the tape are made of metal, so that sliding between the metals causes further remarkable wear and damage.

First, the vapor-deposited tape naturally damages the magnetic surface and becomes unusable, but the magnetic metal powder is further peeled off from the damaged vapor-deposited tape, and the sliding state is continued while adhering to the cylinder or head surface. . The magnetic powder is embedded in the head surface and the cylinder surface in a magnetized state, and also acts to demagnetize or demagnetize the signal recording area of the tape, resulting in large damage that renders the cylinder inoperable.

Further, the fixed lower cylinder has
I mentioned that there is a tape guide on the surface,
This tape guide wears. The tape wound around the cylinder has a high tape tension especially on the exit side of the cylinder, and therefore the wear at this portion is severe. The wear of this part prevents the magnetic tape from running on the proper track. As a result, in reproducing the recording signal, the magnetic head cannot run on the normal track as shown in FIG. 5, and the envelope waveform thereof is extremely distorted.

The above-mentioned problems occur even when the diameter of the conventional aluminum cylinder is reduced. Therefore, when a lighter material is used as the base material of the cylinder, these problems are more likely to occur, it is difficult to easily change the material, and it is difficult to reduce the size and weight of the device body. It was

[0012]

The above-mentioned problems can be solved by using a resin as a material and using a cylinder whose surface is coated with a diamond-like carbon film. Further, the cylinder is obtained by decomposing a gas containing carbon with high frequency plasma and synthesizing a diamond-like thin film on a resin cylinder by self-bias.

[0013]

[Operation] By constructing the cylinder with resin, the weight can be significantly reduced. The type of resin used is not particularly limited, but a material having high rigidity is preferable if possible. As a result, the cylinder weight can be reduced by about 30 to 40% or more compared with the conventional one.

Further, when a diamond-like carbon film is synthesized on the surface of the cylinder, the strength of the surface of the cylinder is improved and the wear resistance can be improved. The diamond-like carbon film has excellent hardness and excellent durability. Therefore, the problems of wear and damage as described above do not occur at all.

Moreover, since the diamond-like carbon film also has excellent lubricity, it is possible to obtain a surface having a low friction coefficient. In particular, the diamond-like carbon film can reduce the friction coefficient to 0.1 or less by containing silicon element in the film. It is said that when silicon atoms enter the diamond-like carbon film, the film surface is inactivated and the friction coefficient decreases. Therefore, by coating the surface of the cylinder with a diamond-like carbon film containing silicon, a cylinder having a coefficient of friction lower than ever can be realized. When the coefficient of friction decreases,
Since the load on the film is also reduced, the wear resistance is further improved. Further, since the lubricity of the tape and the cylinder is dramatically improved, low tension running of the tape can be realized. As a result, the load on the mechanism is reduced,
The size and weight of the magnetic recording device can be reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic view of an embodiment of a cylinder for a magnetic recording apparatus of the present invention. Both the upper and lower cylinders are made of thermosetting resin, cylinder diameter 27mm
The diameter was φ and the surface was coated with a diamond-like carbon film of 0.5 μm.

FIG. 2 schematically shows a cylinder manufacturing apparatus for coating a diamond-like carbon film. A cylindrical substrate holding portion and a high frequency electrode 4 were installed in the center of the vacuum chamber 3 and were directly connected to a motor 9 through a high frequency filter so as to be rotatable. The resin cylinder 1 was set in the base holding portion. Further, the high frequency power supply 7 is connected to the high frequency electrode 4 via the matching circuit 6. A ground electrode 5 was arranged on the outer circumference of the cylinder.

In this state, after evacuating to a high vacuum, methane gas was introduced into this and high frequency power of 50 W was applied to the cylinder 1.
Was applied to the electrode 4 connected to. Methane gas is turned into plasma, and self-bias by electrons is induced on the resin cylinder. A high-quality diamond-like carbon film was synthesized on the cylinder 1 by accelerating ions containing carbon.

When silicon was contained in the diamond-like carbon film, silane gas was added at the same time as methane gas. The diamond-like carbon film in this case was analyzed by Auger electron spectroscopy, and it was confirmed that silicon film was contained in the film. After that, the cylinder was taken out from the vacuum container 3 and the magnetic head was incorporated.

Characteristic evaluation was carried out using the various cylinders produced by the above method. A list of evaluation samples is shown in (Table 1). The tape used was a Co-Ni vapor deposition tape.

[0021]

[Table 1]

First, the cylinder was fixed, the tape was wound, and the tape was repeatedly run to evaluate the change in the dynamic friction coefficient between the tape cylinders.

FIG. 3 shows changes in the friction coefficient between various cylinders and the tape with respect to the number of times the tape is run.

A resin-only cylinder has a very high coefficient of friction with the tape of 0.3 or more, and the coefficient of friction gradually increases as the number of tape runs increases.

The aluminum-made product also has a low initial friction coefficient, but shows a gradually increasing tendency. There were sliding marks on these cylinders.

On the other hand, the surface-coated diamond-like carbon film has a low coefficient of friction with the tape and is stable in running the tape. In addition, those containing silicon have a coefficient of friction lower than 0.1, which is stable over a long period of time.

Next, a tape on which a signal has already been recorded was wound around a cylinder, and the cylinder was rotated at a high speed to perform a still durability test. The tape wrap angle is 27
The test was performed under severer sliding conditions with a 0 degree cylinder rotation speed of 2700 RPM.

FIG. 4 shows the relationship between the rotational speed of the cylinder and the signal reproduction output. In the case of resin cylinders and aluminum cylinders, it can be seen that the reproduction output drops immediately. When the surface of the tape and the surface of the cylinder were observed with a microscope in this state, sliding marks were found on both the cylinder and the tape.

On the other hand, in the case where the diamond-like carbon film is coated, the reproduction output is not reduced.

As described above, according to the present invention, a compact and lightweight cylinder having excellent durability can be realized.

[0031]

As described above, according to the present invention, the weight of the cylinder can be greatly reduced. Further, since the tape can be run at a low tension, the load on the mechanism can be reduced. For these reasons, the magnetic recording device can be made large and small and lightweight, which is a great industrial effect.

[Brief description of drawings]

FIG. 1 is an external view showing an embodiment of a magnetic recording device cylinder of the present invention.

FIG. 2 is a block diagram of an apparatus for manufacturing a cylinder of the same embodiment.

FIG. 3 is a diagram showing the relationship between the coefficient of friction and the number of times of tape running in the example cylinder of the present invention.

FIG. 4 is a relational diagram of a still durability test in an example cylinder of the invention.

FIG. 5 is an explanatory diagram of cylinder operation.

[Explanation of symbols]

 1 Resin Cylinder 2 Diamond-like Carbon Film 3 Vacuum Cistern 4 High Frequency Electrode 5 Ground Electrode 6 Matching Circuit 7 High Frequency Power Supply 8 Raw Gas Cylinder 9 Rotation Motor-10 Plasma 11 Upper Cylinder 12 Lower Cylinder 13 Magnetic Tape 14 Magnetic Head 15 Tape Guide 16 tracks

Claims (3)

[Claims] 1. A cylinder for recording and reproducing a video signal of a magnetic recording device, characterized in that the material is molded of resin and a diamond-like carbon film is synthesized on the surface thereof. 2. A cylinder for a magnetic recording apparatus according to claim 1, wherein the diamond-like thin film contains silicon. 3. A diamond-like carbon film is synthesized on the cylinder surface by making a gas containing at least carbon and silicon into plasma and accelerating and colliding the ions in the plasma with the surface of a resin cylinder. A method for manufacturing a cylinder for a magnetic recording device.