JPH038118A - Manufacture of disk-like magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain the disk-like magnetic recording medium whose mass production efficiency is excellent and whose reliability is high by scanning a laser light to a magnetic recording medium original plate formed by providing a magnetic layer on a longitudinal non-magnetic supporting body and cutting it like a disk. CONSTITUTION:An original plate 4 is irradiated with a laser light 1 through a condensing lens 2, scanned in the scanning direction 3 and cut like a disk. Therefore, as shown in the figure, cutting for generating no waste to the utmost can be selected from a relation of width of the original plate and the diameter of the magnetic recording medium. Also, a distortion generated at the time of blanking is eliminated, as blanking executed by a press machine, therefore, no burr comes to be generated, and irrespective of thickness of the original plate, cutting can always be executed with the same accuracy. As for the laser to be used, when it has an output which can cut the original plate, any laser can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of manufacturing a disk-shaped magnetic recording medium, and particularly to a method of manufacturing a disk-shaped magnetic recording medium that is excellent in mass production efficiency and highly reliable.

[Background Art 1] In recent years, as personal computers and office automation equipment have become more common, demand for disk-shaped magnetic recording media such as floppy disks has increased. Among these, the most common are floppy disks in which a magnetic layer is provided on a synthetic resin film such as polyethylene terephthalate by coating or vapor deposition. It was manufactured by punching out.

[Problems to be Solved by the Invention] However, when punching with a press machine, it is not possible to perform multiple punches due to accuracy, and in an actual production line, the original plate provided with the magnetic layer is cut once from a predetermined diameter. However, the process was time-consuming as it required slitting to a slightly larger width and then punching. Further, the disks that could be punched from the original plate were aligned as shown in FIG. 3, and the efficiency of using the original plate was not high.

Further, when punching with a press machine, as shown in FIG. 4, burrs occur at the edge of the disk, which causes damage to the pad that presses the medium against the head.

Further, since the bidet floppies used in recent electronic cameras are thinner than conventional 3.5" and 5" floppies, it is difficult to press them with precision.

[Means for Solving the Problems] The present invention has been made to solve the above problems, and includes irradiating a magnetic recording medium original plate, which is formed by providing a magnetic layer on a longitudinal nonmagnetic support, with a laser beam, This method of manufacturing a disc-shaped magnetic recording medium is characterized in that the disc-shaped magnetic recording medium is cut into a disc-shape by scanning with the laser beam.

According to the present invention, since the original plate is cut into a disk shape by arbitrarily scanning the original plate with a high-power laser, the original plate after the magnetic layer has been applied can be cut without post-processing. Further, as shown in FIG. 2, the most wasteful cutting method can be selected from the relationship between the original width and the diameter of the magnetic recording medium.

Furthermore, the present invention eliminates the distortion that occurs during punching as in conventional punching with a press machine, eliminating the occurrence of cracks that would damage the pad, and the same accuracy is always achieved regardless of the thickness of the original sheet. Can be cut.

The laser used in the present invention may be any laser as long as it has enough output to cut the original plate, but specifically, CO2 laser, ruby laser, Nd/YAc laser, etc. can be mentioned.

As a method of scanning the laser beam, for example, a method of directly scanning a light source provided on an XY stage, or a method of scanning by reflecting the laser beam with a horigon mirror, etc. can be used.

[Example 1 Next, the present invention will be explained by giving examples.

On both sides of a polyethylene terephthalate film with a thickness of 32 μm and a width of 45 cm, a magnetic layer composed of magnetic powder, a polymer binder, an abrasive, and a lubricant with a thickness of 4 mm was provided to form an original plate.

A 002 laser with an output of 200 W was used as a laser light source. The spot diameter of the laser beam was adjusted to 125 μm in TEM mode using a condenser lens. By scanning this laser beam, a diameter of 47 mm is obtained from the original plate.
The magnetic recording medium was cut. The number of discs obtained is
There were 196 pieces per original plate length.

For comparison, the same original board was first slit into 5 cm pieces.
Thereafter, it was similarly punched out to a diameter of 47 mm using a conventional punching machine using a press. The number of discs obtained was 180 per length of original plate.

Discs obtained in Examples and Comparative Examples, 50 each
Table 1 shows the results of measuring the outer diameter of the sheet using a tool microscope.

Table 1 In addition, Table 2 shows the shape of the cut surface and the observation results of the pad condition after the actual machine running test (200 hours) after the jacket was installed.

Table 2 [Effect of the Invention 1] As explained above, the method of the present invention makes it possible to provide a disk-shaped magnetic recording medium with excellent mass production efficiency and high reliability.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of the present invention, Fig. 2 is a plan view of the original plate after cutting by the method of the present invention, Fig. 3 is a plan view of the original plate after punching by the conventional method, and Fig. 4 is a plan view of the original plate after cutting by the method of the present invention. 1 shows a partial side cross-sectional view of a medium punched by the method. (Unit: mm) ■...Laser beam 3...Scanning direction 5...Magnetic layer

Claims (1)

[Scope of Claims] 1. A magnetic recording medium master plate comprising a magnetic layer provided on a longitudinal non-magnetic support is irradiated with a laser beam and cut into a disk shape by scanning the laser beam. A method for manufacturing a disc-shaped magnetic recording medium. 2. The manufacturing method according to claim 1, wherein there is a plurality of laser light sources.