JPS6220137A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To make mass production of a high-density magnetic recording medium possible by electrostatically charging a high-polymer film right after un-winding and destaticizing the same just prior to taking-up in the case of moving the high-polymer film along a rotary support and depositing a ferromagnetic metal thereon by electron beam evaporation while taking up the film. CONSTITUTION:The high-polymer film is electrostatically charged right after un-winding and is destaticized just prior to taking-up in the stage of moving the high-polymer film along the rotary support and depositing the ferromagnetic metal by evaporation on said film while taking up the film. The film is electrostatically charged by the effect of a high-voltage probe 20 and since the film is brought into tight contact with the respective surfaces of rollers and can by the effect of the electrostatic attraction in the direction perpendicular to said surfaces during the movement of the film in contact with elements 24, 25, 13, etc. constituting the take-up system and therefore, the vapor deposition and taking up are executed after the generation of rubbing grazes is thoroughly suppressed. The stress perpendicular to a take-up shaft is integrated if the film is kept electrostatically charged after the film is wound to a long size. The film is thereby transversely wrinkled and is consequently required to be destaticized. Since the destaticization without contact is desirable, the film is passed in glow discharge and either of ions or electrons are utilized according to polarities.

Description

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

Prior Art Iron oxide fine particles and alloy fine particles currently in practical use are fixed on a polymer film with a binder. As improvements in recording density using magnetic recording media such as so-called coated magnetic tapes and magnetic disks have begun to reach their limits, it is desirable to put into practical use magnetic recording media whose magnetic recording layer is a ferromagnetic metal thin film obtained by a new manufacturing method. It looks like this.

Typical manufacturing methods currently being considered include electron beam evaporation, sputtering, and wet plating, of which electron beam evaporation is the most promising in terms of productivity. [
For example, foreign journal IEE Transaction
On Magnetex (I E E E Transa
tions on magnetics) Vol.
MAG 20. &1, PP, 51-56 (1984
) Reference] FIG. 2 is an internal configuration diagram of a vapor deposition apparatus used for forming a conventional magnetic recording layer. In Fig. 2, 1 is a cylindrical can, 2 is a substrate, 3 is an unwinding shaft, 4 is a winding shaft, 6 is an evaporation source, 6 is a vapor flow, 2 is a mask, 8, 9.1
0 is a discharge electrode, 11 is a guide roller, and 12 is an expander roller.

These components are placed in a vacuum container, evacuated by a vacuum pump, and work to perform electron beam evaporation in an atmosphere containing oxygen gas or the like introduced from the outside as necessary.

The substrate 2 made of a polymer film that has come out of the unwinding shaft 3 is subjected to glow discharge treatment with a discharge electrode 8, and then transferred to an expander roller 1.
2 and is exposed to a limited vapor flow 6 while moving along the cylindrical can 1 in the direction of arrow A, in this case magnetic recording by integral oblique deposition with an ever-changing incident angle. Formation of the layer takes place. The substrate on which the magnetic recording layer has been formed is sandwiched between discharge electrodes 9 and 10 and subjected to discharge treatment, then wrinkles are smoothed out again by the expander 12, and the substrate is wound up by the winding shaft 4.

When the electron beam evaporation of a predetermined length is completed, the winding shaft 4
The processed substrate in a wound state is taken out into the atmosphere and undergoes multiple processing steps such as heat treatment and coating treatment to become a magnetic recording medium such as a magnetic tape or a magnetic disk.

The problem that the invention seeks to solve However, in the method described above, the guide roller.

Because the rotating body, such as a cylindrical can, and the moving substrate do not move in perfect synchronization, extremely shallow scratches may occur on the substrate than expected, resulting in a block error rate when used for short wavelength digital recording. Since there are cases where the amount increases abnormally in the longitudinal position of the tape, an improvement has been desired.

The present invention has been made in view of the above-mentioned problems, and allows mass production of high-density magnetic recording media with improved block error rate by preventing relative motion between the substrate and the rotating body. The present invention provides a method for manufacturing a magnetic recording medium that can perform the following steps.

Means for Solving the Problems In order to solve the above problems, the method for producing a magnetic recording medium of the present invention involves electron beam evaporation of a ferromagnetic metal along a rotating support while winding a polymer film. The method is characterized in that the polymer film is electrostatically charged immediately after unwinding, and static electricity is removed immediately before winding.

For production The present invention relates to the above-described method 9 and a guide roller.

Because an attractive force acts between rotating bodies such as expander rollers and cylindrical cans and the polymer film, they do not move relative to each other, but move in complete synchronization, so there is no scratching on the soft polymer film. This means that the abnormal increase in the block error rate, which is triggered by film scraps caused by scratches, can be completely eliminated in the longitudinal direction.

EXAMPLE Hereinafter, a method for manufacturing a magnetic recording medium according to an example of the present invention will be described with reference to the drawings.

FIG. 1 is an internal configuration diagram of a vapor deposition apparatus used to carry out the present invention.

In FIG. 1, 13 is a cylindrical can, 14 is a substrate made of polymer film, 15 is an unwinding shaft, 16 is a winding shaft, 1 is an electron beam evaporation source, 18 is a vapor flow, 19 is a mask, 2 o is a high-pressure glove that electrostatically charges polymer film immediately after unwinding it. 21 and 22 are glow discharge electrodes for static elimination, 23 is a discharge electrode that can be used for purposes such as glow discharge treatment or ion etching treatment before vapor deposition, 24 is a guide roller, and 26 is an expander roller.

20 is an electrode with a tungsten carbide whisker at its tip, which is 10 negative with respect to the ground potential.
The film is charged by applying 0 KV and emitting electrons by a strong electric field. High pressure glove 2
The film becomes electrostatically charged due to the action of 24.25.1
Even when moving while in contact with winding system components such as 3rd etc., the rollers and cans are in close contact with each other in the vertical direction due to the action of electrostatic attraction, so there is no mutual scratching, completely preventing the occurrence of scratches. It is possible to perform vapor deposition and take up one roll after suppressing the amount.

If a long film is electrostatically charged when it is wound up, the stress perpendicular to the winding axis will be accumulated, resulting in horizontal wrinkles in the film, so it is necessary to remove the static charge. Since static elimination is preferably done without contact, it is sufficient to pass through a well-known glow discharge and use either ions or electrons depending on the polarity.

A 3,000 m polyethylene terephthalate film with a thickness of 1 µm was prepared as a polymer film, and an electron beam evaporation source was placed directly below the 1 m diameter of the cylindrical can.
Oxygen partial pressure of 4X10' Torr [I
Co -
A N i -0 (Ni 20 wt %) film was formed, and stearic acid was vacuum-deposited thereon by 40 people, flattened, and slit to obtain a magnetic tape with a width of 8M1.

PCM recording and playback were performed using a commercially available 8 mm video tape recorder, and the block error rate was measured over the entire length.

A comparative example was also made into a tape and measured using the same procedure.

In the present invention, electrostatic charging is performed at -10QKv, and in the comparative example, the globe voltage is set to o■.

Static elimination processing is 80Hz, 300V, IA, 0.15 Tor
This was made common by treating both sides of the substrate with argon glow.

Put 90m into a cassette and randomly extract 50 volumes.

When the error rate was measured, the present invention achieved an average error rate of 10-
With an error rate of 4, the maximum value is 2. I x 10-4, whereas the comparative example had an average value of 3.9 x 10
The maximum value was as large as 2x10-2, and there were 60 cores and 31 cassettes exceeding 2x10.

As described above, according to this embodiment, by electrostatically charging the polymer film immediately after unwinding, it is moved and wound in synchronization with the guide roller, expander roller, cylindrical can, etc., so that scratches occur. Prevent it.

This prevents the scraped constituent material of the polymer film from adhering to the surface of the magnetic recording layer and causing an abnormal block error rate.

In the above-described embodiments of the present invention, the rotary support body is a cylindrical can, but a rotary belt or a combination of a rotary can and a rotary belt can also produce the same effect.

The electrostatic charging method may be based on electron injection, ion injection, or a combination of both, and there is no particular difference depending on the method.

In addition to polyethylene terephthalate film, the materials used to obtain the magnetic recording medium according to the present invention include polycarbonate and polysal 7on.

In addition to polyamide, polyimide, polyethylene naphthalate, etc., F/l/A, Co-N i-0, C
o -0゜Co-Cr, Co-Ti,
Go-Si, Co-Ta.

Co-W, Co-Mo, Co-Mg,
Co-Cr-Ga.

Examples include ferromagnetic metals such as Co-Ru-0.

Effects of the Invention As described above, according to the present invention, even in short wavelength digital recording, it is possible to mass-produce long media or large area media materials with extremely low error rates, and an excellent effect can be obtained. I can do it.

[Brief explanation of the drawing]

FIG. 1 is an internal configuration diagram of an example of a vapor deposition apparatus used to carry out the present invention, and FIG. 2 is an internal configuration diagram of a conventional vapor deposition apparatus. 13... Cylindrical can, 14... Substrate (
polymer film), 17...electron beam evaporation source, 2o...high pressure probe, 21.22...
...Glow discharge electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person13
-11 Cylindrical Idaigo Inn

Claims (1)

[Claims] A method of vapor-depositing a ferromagnetic metal along a rotating support while winding a polymer film, which is characterized by electrostatically charging the polymer film immediately after unwinding and removing the charge immediately before winding. A method for manufacturing a recording medium.