JPH0233293Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a magnetic recording disk such as a flexible magnetic disk, for example, and includes forming grooves on the outer periphery of the magnetic recording disk made by vapor deposition method or plating method. It is an object of the present invention to provide a magnetic recording disk in which curling does not occur on the magnetic recording disk and does not interfere with reproduction.

Conventionally, there have been so-called coated magnetic recording disks in which magnetic powder such as γ-Fe ₂ O ₃ powder or CrO ₂ powder is coated on a non-magnetic substrate using a binder, but there is a need for high-density recording and reproduction. As demand increases,
For example, a so-called metal thin film in which a magnetic layer is provided on a flexible non-magnetic substrate such as polyester or polyimide without using a binder by a vapor deposition method such as vacuum evaporation, sputtering, or ion plating or a plating method. Type magnetic recording disks have attracted attention, and efforts are being made to put them into practical use.

By the way, a major problem in putting this metal thin film type magnetic recording disk into practical use is that if the magnetic layer is constructed using the vapor deposition method or the plating method, curling will inevitably occur on the magnetic recording disk due to the manufacturing process. will occur. This curl phenomenon occurs not only when a magnetic layer is provided on one side of the flexible nonmagnetic substrate, but also when it is provided on both sides, due to subtle differences in characteristics between the two sides.

Therefore, in order to prevent curling, for example, in the case of a magnetic recording disk in which a magnetic layer is formed on only one side by the vapor deposition method, uncurling is performed using a hot roll, but this The number of manufacturing steps for magnetic recording discs increases, which increases costs.Furthermore, even if uncurling is done carefully, it is often not possible to uncurl the disks sufficiently, resulting in poor manufacturing yields.Furthermore, vapor deposition is required on both sides. In the case of magnetic recording disks in which the magnetic layer is composed of
Moreover, even if this method is used, it is still more difficult to restore the curl that has occurred.

The present invention eliminates the above drawbacks, and examples thereof will be described below.

Figures 1a and 1b show one of the magnetic recording disks according to the present invention.
FIG. 2 is a plan view and a cross-sectional view of an example.

In the same figure, 1 is a flexible non-magnetic disk (base) made of polyester or polyimide, etc., with a thickness of about 50 μm, for example, on both sides of which the gas pressure (gas is argon) during sputtering is about 2×10 ^-2 torr;
For example, a Co-Cr magnetic thin film layer was formed with a thickness of about 0.8 μm on each side by sequential high-frequency sputtering under sputtering conditions such that the RF power density was 2 W/cm ² 5. An inch flexible magnetic disk.

2 is a 5-inch flexible magnetic disk 1
Approximately 1 to 3 inches from the outer edge before punching
A ring groove (a ring-shaped rib is formed on the opposite side of the flexible magnetic disk) with a width of about 1 to 2 mm, e.g. 1 mm, and a depth of about 0.05 to 1 mm, e.g. 0.3 mm, is formed on the inside of the flexible magnetic disk. This is a ring groove formed using a press ring so that the

When a magnetic recording disk is constructed in this way, after forming a magnetic thin film layer on the base by vapor deposition method or plating method, grooves are formed by pressing at positions corresponding to the inside of the desired shape. Thereafter, the magnetic recording disk formed by punching out a desired shape along the outside of the groove is free from curling and is in good condition.Moreover, manufacturing is simple, and the yield is significantly improved. In addition, even after manufacturing, it is resistant to environmental changes, difficult to deform, highly durable, difficult to reproduce, and easy to store.

Note that the process of press forming the grooves and the process of punching into a desired shape may be performed simultaneously.

As mentioned above, the magnetic recording disk according to the present invention has grooves formed on the outer periphery of the magnetic recording disk in which the magnetic recording layer is formed on the base by the vapor deposition method or the plating method, so that the magnetic recording disk does not curl. It has features such as being easy to manufacture, improving yield, being resistant to environmental changes, making it easy to store, and hardly causing problems in recycling.

[Brief explanation of the drawing]

FIGS. 1a and 1b are explanatory diagrams of an embodiment of a magnetic recording disk according to the present invention. 1...Flexible magnetic disk (magnetic recording disk), 2...Ring groove (groove).

Claims (1)

[Scope of utility model registration request] 1. A magnetic recording disk, wherein a magnetic recording layer is formed on a base by a vapor deposition method or a plating method, and a groove is formed on the outer periphery of the magnetic recording disk.