JPS58196626A - Manufacture of magnetic recording medium - Google Patents

Abstract

PURPOSE:To execute high-precision abrasion working and to raise productivity, by arranging at least 2 abrasion heads along the traveling direction of a roll of a magnetic sheet, and pressing an abrasive sheet travelling in the direction reverse to said direction between said head and the magnetic sheet. CONSTITUTION:The magnetic rolled sheet 1 prepared by forming magnetic layers on both sides of a base made of polyester film or the like is cleaned of dust on its surface, and abraded with abrasive sheets 7, 7 traveling in the direction reverse to the direction (a) of the magnetic sheet 1 by pressing the sheets 7, 7 to both sides of the sheet 1 with the >=2 abrasive head 6 (10 heads illustrated in the figure) of which the pressing faces 6a, 6a pinch the sheets 7, 7 and the sheet 1. The roll of abraded sheet 1 is punched to obtain a magnetic disc of a prescribed diameter, high in abrasion precision, and superior in electromagnetic conversion characteristics with high productivity.

Description

[Detailed Description of the Invention] This invention provides a method for manufacturing a magnetic recording medium such as a magnetic disk.
In particular, the present invention relates to an improvement in so-called polishing for smoothing the surface of a magnetic layer.

Conventionally, the method used to polish magnetic disks, etc. is to form a magnetic layer on a base, punch it out into a disk shape, and then insert it between two grindstones and polish it. Polishing each sheet was troublesome and had low productivity. Furthermore, in the case of magnetic tapes, etc., a method is used in which a mirror polishing roll is pressed against the original magnetic sheet, but this method does not necessarily guarantee satisfactory polishing accuracy. I couldn't say that.

This invention aims to provide a new and useful processing method that can polish a magnetic sheet raw fabric with high precision from the above-mentioned viewpoint. At least two polishing heads are arranged in parallel along the same line, and an abrasive sheet running in a direction opposite to the traveling direction between the heads and the raw fabric is pressed against the magnetic layer surface of the raw fabric by the polishing head. It consists in polishing.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

Figure 1 schematically shows the manufacturing process of the magnetic disk of the present invention, in which A is the roll-unwinding process of a magnetic sheet material 1 made by coating both sides of a base such as a polyester film with magnetic paint. It is. B is a cleaning process for removing dust and the like that adheres to the magnetic layer surface after the above process, for example, as shown in FIG. One magnetic layer surface of the raw fabric 1 is pressed against the magnetic layer via a roll 3, a winding roll 4, and a pressing roll 5.

C is the most important polishing process of the present invention, which is provided after the above-mentioned cleaning process, as shown in Figure 3.
0 polishing heads 6.6 are arranged in parallel, and this head 6.
An abrasive sheet 7.7 running in a direction opposite to the running direction a between the magnetic sheet material 1 and the magnetic sheet material 1 is pressed against the magnetic layer surface of the material material 1 by the head 6.6. .

Here, each polishing head 6.6 has a flat pressing surface 6a, 6a against the magnetic sheet raw material 1, and a pad (
(not shown), and is configured to be able to be pressed against the original fabric 1 by a spring (not shown). Also,
The abrasive sheet 7.7 has a structure in which an abrasive layer made of abrasive powder such as alumina oxide, titanium oxide, silicon oxide, etc. is dispersed and bonded with a suitable binder on a base such as a polyester film. is pressed against the magnetic layer of the original magnetic sheet 1.

D is a cleaning step for removing abrasive powder adhering to the original magnetic sheet 1 after polishing, and has the same structure as the step B described above. Further, E is a punching step after the cleaning step, in which the magnetic disk is punched out to a predetermined diameter to form the intended magnetic disk.

As described above, in the method of the present invention, the polishing process is performed by pressing the abrasive sheet against the traveling magnetic sheet material, so the polishing operation is faster than in the conventional method of polishing after punching out the disk. It is easy to use, improves the productivity of magnetic disks, and has a superior smoothing effect compared to methods that press mirror-finishing rolls against each other. In addition, since a large number of polishing heads are used which are arranged in parallel in the running direction of the original magnetic sheet to press the polishing sheet,
One person. Polishing spatula 1. ) oshi, shito, men. a, 6a (7)
Impact 1 is the pressing surface 6a of the next polishing head
, 6a, the area of the pressing surface is improved accordingly, and macroscopic smoothness defects such as polishing unevenness are suppressed.

Although Fig. 3 shows an example in which 100 polishing heads 6.6 are arranged in parallel along the running direction, generally 1 polishing head 6.6 is installed in the running direction.
It is sufficient that at least two of them are arranged in parallel with an interval of 0 to 50 fights. However, in terms of surface accuracy, it is more desirable. In addition, two or more guide rolls 8.8 are provided between the polishing heads, which are arranged in parallel along the running direction of the polishing sheet 7.7.
may be made to run as shown by the chain line in the figure.

Furthermore, in FIG. 3, the polishing heads 6.6 on both sides of the magnetic sheet raw material 1 are opposed to each other, and the respective pressing surfaces 6a, 6a are pressed against the polishing sheet 7.6 by means of springs (not shown).
7 and the original fabric 1, but as shown in FIG. Furthermore, the upper and lower heads 6.6 may be arranged alternately along the traveling direction aI.

Next, in order to clarify the effect of this invention method mentioned above,
As a raw magnetic sheet, γ-Fe203 is applied to both sides of a polyester film as a binder consisting of a hydroxyl group-containing vinyl chloride-vinyl acetate copolymer, an acrylonitrile-butadiene copolymer, and a polyfunctional isocyanate compound.
Using a magnetic layer made by dispersing and binding powder,
Using a commercially available abrasive tape with alumina oxide abrasive powder as an abrasive sheet, a magnetic disk was obtained by the method shown in Figs. We investigated the incidence.

The number of polishing heads disposed along one running direction was 10, and the distance between each head was 3olI#I. Further, the length of the pressing surface of each of the heads along the running direction was 5 baits. In addition, the running speed of the original magnetic sheet is 2
0.000rsm/min, the running speed of the abrasive sheet is 12
Fin/min.

The above test results were as follows. Here, the comparative example is the result of polishing each magnetic disk, and the surface roughness was measured using a stylus surface roughness meter (Tokyo Seimitsu, SUNFCOM 60B-101) of 0.8 mm Cut.
OFF, the number of polishing irregularities occurring per 100 magnetic disks was evaluated by visual observation.

Invention example Comparative example Surface roughness 0.030 μm 0.035 μm
(C, L, A) Polishing unevenness Approximately 1 disk Approximately 5 disks occurrence rate As is clear from the above test results, the method of the present invention makes it easy to obtain magnetic disks with high polishing accuracy. It can be seen that the productivity and electromagnetic conversion characteristics of magnetic disks can be greatly improved.

[Brief explanation of drawings]

FIG. 1 is a schematic process diagram showing an example of the manufacturing method of this invention, FIG. 2 is an explanatory diagram of the cleaning process in this invention, FIG. 3 is an explanatory diagram showing an example of the polishing process in this invention, and FIG. Grinding of this invention 1...magnetic sheet raw fabric, 6
．． 6... Polishing head, 7.7... Polishing sheet, a.
...Travel direction.

Claims (1)

[Claims] (1) At least 2 along the running direction of the original magnetic sheet
Abrasive heads are arranged in parallel, and an abrasive sheet that runs between the heads and the original fabric in a direction opposite to the traveling direction is pressed against the magnetic layer surface of the original fabric by the polishing head to perform polishing processing. A method for manufacturing a magnetic recording medium characterized by: