Sony Corporation

Kiyoyuki Miyata

Takashi Abe

Yoshiyuki Watanabe

Masanori Takano

Nobufumi Takasu

Hiroshi Morita

Shuichi Kikuchi

Eiji Nakashio

Hiroshi Meguro

Shintaro Higuchi

There is provided a magnetic recording medium including a magnetic layer. The magnetic layer has a servo signal recorded thereon by magnetizing a part of the magnetic layer in a first direction. The first direction contains a component of a perpendicular direction that is perpendicular to a top surface of the magnetic layer. The magnetic layer is pre-magnetized in a second direction before recording of the servo signal. The second direction contains the component of the perpendicular direction. The second direction is opposite to the first direction.

Magnetic recording medium, servo signal recording apparatus and method of producing magnetic recording medium

After a DC erasing is performed in a direction by permanent magnets on a servo signal recording part, servo signals are recorded in the signal recording area of the servo signal recording part by a magnetic field in the direction opposite to that of the DC erasing. Thus, in a recording method for a magnetic recording medium having a data signal recording part and the servo signal recording part on a magnetic layer, accurate servo signals can be recorded and reproduced even on the medium having the magnetic layer of 0.13 &#x3bc;m or smaller.

Recording method for magnetic recording medium, recording device for magnetic recording medium and magnetic recording medium

Method and device for recording data and erasing servo data

A center core for a disc-shaped recording medium. The center core comprises a flange section for supporting the disc-shaped recording medium. A generally cylindrical section having a bottom wall is formed integral with and located radially inward of the flange section. A plurality of supportable standard sections are formed at the bottom wall of the cylindrical section by making a press working on the bottom wall of the cylindrical section in a manner to project toward the lower surface side of the center core. The supportable standard sections define a supportable surface through which the center core is placed on a turn table of a disc drive device.

Center core for disc-shaped recording medium and process of producing same

A disk cassette including a cassette housing having upper and lower shells in which a freely rotatable disc is accommodated. A shutter is slidably secured in parallel relation to the side surfaces of the cassette housing and opens/closes a head insertion hole formed in the cassette housing. The disk cassette further includes a shutter spring assembly which has one end thereof hooked to the cassette housing and the other end thereof hooked to the shutter and thereby urges the shutter so as to close the head insertion hole. An insertion groove is provided in the cassette housing for inserting the shutter spring assembly thereinto and be covered by the shutter when the shutter closes the head insertion hole.

Spring assembly for biasing shutter of a disk cassette

A lifter for a disk mounted in a disk cartridge comprises a lifter body formed of a flexible thin plate material and having a fold, folded at a predetermined angle so as to define a fixing member at one side of the fold and a pressing member at the other. A cutout is formed at a position across the fold to minimize distorting forces concentrated at the fold.

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Miyagi, Japan

Kiyoyuki Miyata