JPS60127530A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To prevent a magnetic metallic thin film from being dropped out partially by sliding and contacting at a tape running time, by cutting out obliquely a part, which is a specific number of times as long as the thickness of a magnetic tape, of the cut end face of the magnetic tape, where a magnetic metallic thin film is formed on the surface of a supporting material, so that the cut end face has a trapezoid shape having the rear face of the supporting material as the bottom. CONSTITUTION:A cutter where a rotary shearing edge 6 is supported by a holding shaft 7 and a thick edge 8 is supported by a holding shaft 9 is used to cut a magnetic recording medium 5 so that the cut end face of the magnetic tape, where a magnetic metallic thin film layer 4 is formed on a high polymer substrate 3, has a trapezoid shape having the rear face of the substrate 3 as the bottom and the rate of cutting-out, namely, a ratio of the cut-out width of the magnetic layer 4 to the sum of thicknesses of the substrate 3 and the magnetic layer 4 is 0.5-2, and thereafter, a polishing grindstone 11 is used to polish both end faces in the breadthwise direction of a magnetic recording medium 10 cut at a prescribed angle A. Thus, drop-out and output variance due to dropping-out of the magnetic layer 4 are reduced when the magnetic tape is slid on a control post while contacting.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to improvements in magnetic recording media such as magnetic tapes in the field of magnetic recording.

Conventional Structure and Problems In recent years, magnetic recording media have been moving toward higher density recording in audio and image recording.

Among these, the magnetic layer is undergoing technological innovation from a coated type to a metal thin film type.

A conventional metal thin film type magnetic recording medium will be explained below.

FIG. 1 shows a cross-sectional view of a conventional magnetic recording medium, and numeral 1 indicates a polymer substrate that constitutes the entire magnetic recording medium. Reference numeral 2 indicates a magnetic layer, which is a thin metal film layer of magnetic material. However, in the above structure, when looking at the end, the magnetic layer and the substrate layer are in a straight line at right angles to the surface, and when running as a tape, it comes into contact with the regulating post and slides. There is a problem in that the magnetic layer part is missing and dropouts or output fluctuations occur when high-density recording is performed.

Purpose of the Invention The present invention solves the above-mentioned conventional problems, and is a metal thin film type magnetic recording tape for reducing dropouts and output fluctuations when used as a magnetic recording tape for tape recorders, VTRs, etc. The present invention provides a magnetic recording medium.

Structure of the Invention The present invention provides a method for cutting the cut end surface obliquely by 0.5 to 0.5 of the thickness of the magnetic recording medium.
It is a metal thin film type magnetic recording medium that has the feature of removing twice the area, and when used as a magnetic tape,
This reduces the amount of magnetic powder generated by the destruction of the tape end face, thereby reducing dropouts and output fluctuations.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a diagram showing the basic configuration of a metal thin film type magnetic recording medium in an embodiment of the present invention. In FIG. 2, 3 is the substrate of the magnetic recording medium, and 4 is the magnetic layer of the magnetic recording medium. Figure 2 and 3 show a polymer substrate, and the specific materials used are polyethylene terephthalate, polyimide, and polyamide.The magnetic layer 4 is made of Go.
, CoNi alloys, or oxides such as Fe, ye2o3, etc. are used.

The method for forming a magnetic recording medium is to hold the substrate in vacuum at V'c L, provide a cooling can inside, and transport the substrate while making contact with it. Body metal is melted, vaporized, and scattered to form a thin metal film.

The thickness of the substrate is often about 6071 to 1077, and the thickness of the magnetic layer is 0.2 II - 0.1
Formed in the μ range. In this way, a metal film is formed by vapor deposition while transporting the substrate in a vacuum, and by winding it up, a long metallized film is created.This metallized film can be cut to the width of a magnetic recording tape. It becomes a magnetic recording medium.

In the metal thin film type magnetic recording medium constructed as described above, when looking at a cross section of the magnetic recording medium as shown in FIG. 1, the magnetic layer and the substrate are on the same line at right angles to the medium surface. When such a magnetic recording medium is used in a recorder, VTR, etc., the end surface of the magnetic recording medium becomes a guide boss for running!・As the magnetic layer slides, it breaks and peels off, becoming magnetic powder that adheres to the magnetic recording medium and repeats its travel. Some of these are
It adheres to magnetic heads, etc. inside devices, causing dropouts or output fluctuations. Therefore, in the present invention, as shown in FIG. 2, such a magnetic recording medium is used in tape recorders, VTRs, etc., in which the end face is formed at an angle with the medium surface and the magnetic layer is retracted from the substrate. When used, only the substrate of the magnetic recording medium slides on the guide post for tape running, and the magnetic layer does not come into contact with it, so no damage occurs.
The occurrence of dropouts and output fluctuations is improved.

A more specific embodiment of the present invention will now be described. The substrate shown in FIG. 2 was made of polyethylene terephthalate and had a thickness of 15 mm, and the magnetic layer No. 4 was formed at 61t. The metallized film is shown in FIG. FIG. 5 shows the cut magnetic recording medium, which is cut to the width of the magnetic recording medium by a rotary shearing force, 6 is a thin blade for shearing force, and T is a shaft that holds one blade. 8 is a thick blade, and 9 is a shaft held by the thick blade. FIG. 3 is a cross-sectional view of the rotary shearing force, and the magnetic recording medium is continuously cut while the blade rotates. With such a blade, a magnetic recording medium can only be cut at right angles to the surface of the medium.

In order to form a medium obliquely to the magnetic recording medium as shown in FIG. 2, it is necessary to use an end face polishing device shown in FIG. 4. FIG. 4 shows a schematic diagram of polishing a magnetic recording medium. FIG. 4 shows a magnetic recording medium, and 11 is a grindstone for polishing.

The material of the whetstone is ceramic or super steel so that it is not easily worn away by magnetic powder, and the shape of the whetstone is 10 mm in width when the polished surface is well polished to about 13 mm. The magnetic recording medium and the grindstone are arranged with the angle A set as shown in FIG. In this state, the magnetic recording medium is run at a speed of 100 m/min in the direction of the arrow shown in FIG. 4, and the end face of the magnetic recording medium is polished to a certain angle.

The other end face is also processed under the same conditions. The appropriate range for setting the angle JIA is 0.6 to 2 times, considering the ratio between the thickness of the magnetic recording medium and the removal width of the magnetic layer portion.

Expressed as a formula, when looking at the improved effect using a commercially available VHS video deck, when the rejection rate was 0.2, dropouts occurred at more than 100 cases per minute, but when it was set to 0.5, dropouts occurred at 50 cases per minute. /
When the removal rate reached 1 minute or more, it became about 20 pieces/minute. In addition, the fluctuation in output was 20% when the removal rate was 0.2, but it was within 5 factors when the removal rate was 0.6. This tendency did not change even when the removal rate increased, but when the removal rate increased to 2 or more, the precision of tape width deteriorated and the removal of the magnetic layer by partial stripping required for recording became more difficult. Therefore, the limit of the removal rate is 2.

The effect of shaping the end face of a magnetic recording medium to be particularly oblique is good if
It has the advantage of being easy to process when formed by a shop or the like. Furthermore, when used as a tape, the number of points in contact with the regulating portion of the guide post becomes smaller during tape running, and running resistance can be reduced. For these reasons, fluctuations in the tape during running are suppressed, and as a result, output fluctuations are suppressed to within two factors. For comparison, a magnetic recording medium having a structure in which the end face is not beveled had a variation in output during running of 5%. The method of measuring the output fluctuation is expressed as the ratio between the maximum value and the minimum value of the output, and the time is the value over 10 minutes.

Although the present example specifically demonstrated the effect, it was confirmed that the end face of the magnetic recording medium only needs to have the magnetic layer inside the substrate, and that the same effect can be obtained if the magnetic layer has such a structure.

Effects of the Invention As described above, the present invention provides a magnetic recording medium in the form of a metal thin film, in which the cut end surface is obliquely removed in a range of 0.5 to 2 times the thickness of the magnetic recording medium. When used as a magnetic recording tape or magnetic recording medium for recorders and VTR'%, dropouts and output fluctuations can be reduced, and its practical effects are significant.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a conventional metal thin film type magnetic recording medium, FIG. 2 is a sectional view showing a metal thin film type magnetic recording medium in an embodiment of the present invention, and FIG. 3 is a sectional view showing a magnetic recording medium of a tape type. FIG. 4 is a cross-sectional view of a cutting device that cuts the magnetic recording medium into widths, and a perspective view of a device that polishes and shapes the end face of a magnetic recording medium. 1...Polymer substrate, 2-...Magnetic layer, 3.
...Polymer substrate, 4...Magnetic layer, 5...Magnetic recording medium, 6...Thin blade, 7...Shaft for holding the thin blade, 8... Thick blade, 9...A shaft for holding the thick blade, 10...Magnetic recording medium, 11...
Polishing whetstone.

Claims (1)

[Claims] 1. A magnetic recording medium comprising a thin metal film on a support surface, the cut end surface of which is obliquely removed in an area of 0.5 to 2 times the thickness.