Hitachi, Ltd.

Hitachi Maxell, Limited

Hitaci Maxell, Ltd.

Hiroshi Ishihama

Hiroshi Obara

Yoshitaka Kojima

Nobuhiro Umebayashi

Shizuka Yamaguchi

Shoichi Nakashima

Shoichi Sakamoto

There is provided a stamper for producing a recording medium exhibiting excellent durability and capable of stably forming projections and pits and a method of producing the stamper. A stamper for producing a recording medium comprising projections and pits in a predetermined pattern on the surface thereof, wherein a value of tan .theta..sup.-1 obtainable from an enlargement angle .theta. of an output from a cartridge with respect to an enlargement of an output denoting a load measured by a test of scratching the surface having the projections and pits under conditions that a diameter of a stylus is 100 .mu.m and a loading speed of 1 .mu.m/second is 1.3 or more.

Stamper for producing recording medium

A floppy disk unit including a cartridge case or a jacket, a flexible magnetic disk rotatably accommodated in the cartridge case or the jacket, and liners disposed on the inner surface of the cartridge case or the jacket, wherein at least the surface layer of each of the liners in sliding contact with the magnetic disk is made from a fiber material such as rayon fiber, polyamide fiber, polyester fiber, or polynosic rayon fiber, each fiber having a diameter of 10 to 30 .mu.m, and the fiber material contains inorganic oxide material powder such as titanium oxide having an average diameter of 0.01 to 1 .mu.m by weight ratio 0.1 to 10%.

Floppy disk unit with liner of fibers containing inorganic oxide powder

Growing community of inventors

Shimotsuma, Japan

Hiroshi Ishihama