Victor Company of Japan, Limited

Takayuki Deno

Osamu Kobayashi

Ikuo Matsumoto

Noboru Watanabe

Tsutomu Matsumoto

Kenichi Shimomai

Tsutomu Yashiro

Kenichi Kikuchi

Toyohito Asanuma

Shigeru Nakano

Fumitaka Tsuji

Masamichi Saito

Takumu Tada

Masaru Hanayama

Kazuo Shishime

Toshimitsu Saitou

When an LPP (land pre-pit) is formed between shallow grooves or shallow pits, the LPP is formed on a land existing between the shallow grooves or the shallow pits. Further, the LPP is formed in a position displaced from a centerline of the land in the radial direction by a predetermined amount. Furthermore, a laser beam power utilized for forming a shallow groove or a shallow pit adjacent to the LPP is reduced so as to be lower than a regular laser beam power.

Optical disc having land pre-pits and variable groove depths

A disclosed magnetic recording medium is provided with a single magnetic layer coated on one surface of a non-magnetic substrate. The magnetic layer has a thickness of not less than 2 .mu.m, protrusions on a plane of a height of 10 nm from a center plane in measurement of surface roughness of the magnetic layer with a density of 5000 to 9000 protrusions/mm.sup.2 and protrusions on a plane of a height of 30 nm from the center plane with a density of 500 to 2000 protrusions/mm.sup.2.

Magnetic recording medium

A magnetic recording medium has a substrate and a magnetic layer formed on the substrate. The magnetic layer includes magnetic powder and a binder for binding the magnetic powder on the substrate. The binder includes at least a resin component containing at least an aminoquinone structure selected from an aminoquinone structure group shown with formulas (1-1a), (1-1b), (1-3a) and (1-3b) as a constitutional unit and at least a polar group selected from a group shown with a formula (1-2) in a composition of the resin component. Thus, the magnetic recording medium has excellent corrosion resistance of the magnetic powder and excellent conservation and running durability.

Magnetic recording medium and binder for use with magnetic coating in

The present invention provides a magnetic recording medium such as a magnetic tape suitable for long play with the thickness of the magnetic tape bring less than or equal to 12.5 without degrading the electro-magnetic conversion characteristic of the head-tape contact characteristic of the magnetic tape. The magnetic tape comprises a non-magnetic film base of thickness dA and a magnetic layer on the non-magnetic film base of thickness dM with the ratio of dA/dM.ltoreq.3.6 and a cupping rate defined as a ratio (A/B.times.100%) of a height A of a curled tape to a width B of curled tape in the traversing direction of .ltoreq.10%. The non-magnetic film vase has a first Young's modulus Y(MD) is a longitudinal direction of the magnetic recording medium and a second Young's modulus Y(TD) in a traversing direction thereof, wherein the first and second Young's modulusli y(MD) and Y(TD) respectively satisfy inequalities (1), (2) defined as follows:

Magnetic recording medium with specified transverse and machine

A magnetic recording medium comprising a non-magnetic substrate, a magnetic layer formed at one surface of the substrate, and a back coat layer formed at the other surface of the substrate wherein the back coat layer contains a thermosetting resin and a photosetting resin and its light transmittance is at least 1%. A process for producing a magnetic recording medium which comprises the steps of applying a back coat layer containing a thermosetting resin and a photosetting resin and having a light transmittance of at least 1% to one surface of a non-magnetic substrate; irradiating the back coat layer with a light from both surfaces to carry out photosetting; applying a magnetic layer to the other surface of the non-magnetic substrate; winding the double-coated substrate in the form of a roll; and thermosetting the back coat layer. The magnetic recording media having excellent characteristics can be easily obtained without requiring any complicated apparatus.

Magnetic recording media comprising a back coat containing a mixture of

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Mito, Japan

Takayuki Deno