Ricoh Company, Ltd.

Hazime Machida

Motoharu Tanaka

Hiroshi Tamura

Hitoshi Nakamura

Atsuyuki Watada

Fumiya Omi

Nobuyuki Koinuma

Tadashi Saito

Masayuki Kuzuwata

Hiroshi Kobayashi

Kakuji Murakami

Yuziro Kaneko

This invention provides a metal oxide magnetic substance represented by the following general formula:

Metal oxide magnetic substance and a magnetic film consisting thereof

The present invention provides a metal oxide magnetic substance represented by the general formula I:

Magneto-optic recording medium having a metal oxide recording layer

Ferrimagnetic oxides of the following formula, ##EQU1## wherein Me represents at least one element selected from the group consisting of Ba, Sr and Pb, M.sub.I is at least one element selected from the group consisting of Ga and Al, M.sub.II is at least one element selected from the group consisting of Bi, Gd, Tb, Dy, Ho, La, Y, Co, Zn, Ti, Sc, In, Sn, Ca, Cr, Ni and Ge, 1.ltoreq.x.ltoreq.8, 0&lt;y.ltoreq.6, 1.ltoreq.x+y.ltoreq.8, m is an ion valence of M.sub.I and n is an ion valence of M.sub.II, and a magneto-optical recording medium comprising a transparent substrate, a perpendicular magnetic-anisotropic magnetic film layer formed on the substrate, which magnetic film layer comprises one of the ferrimagnetic oxides of the above formula, and a reflection layer formed on the magnetic film layer, are disclosed.

Ferrimagnetic oxides and magneto-optical recording medium employing the

A magneto-optical recording medium is disclosed, which comprises a transparent substrate, a vertical magnetic-anisotropic magnetic film layer formed thereon, which magnetic film layer comprises a ferrimagnetic oxide of the following formula

Magneto-optical recording medium having a ferrimagnetic recording layer

A magnetic recording and playback apparatus of perpendicular recording type comprises a main pole having a magnetic axis which is normal to a recording surface of a magnetic record medium, an auxiliary magnetic pole disposed in surrounding relationship with the main pole with a small clearance from the lateral side thereof, a coil disposed on part of the auxiliary pole, and a yoke having its one end connected to the auxiliary pole and having its other end of a relatively large area disposed in opposite relationship with the recording surface of the record medium. The free end of the main pole is disposed in contact with the surface of the record medium while the yoke is disposed at a given distance from the surface of the record medium. During a recording operation, a current is passed through the coil in accordance with information to be recorded. Thereupon, a magnetic flux is concentrated in the free end of the main pole to cause an inversion of magnetization in that region of a magnetic layer of the record medium which is contacted by the main pole, thus recording the information. During a playback operation, the free end of the main pole picks up a magnetic flux which depends on the magnetization, representing the information, recorded in the magnetic layer of the record medium, producing a corresponding current flow through the coil. An output current from the coil is utilized for reproduction of the recorded information.

Magnetic recording and playback apparatus of perpendicular recording type

A method for desensitizing an offset printing plate which comprises applying an aqueous desensitizing composition consisting essentially of at least one complex to a non-image area of the offset printing plate having an oleophilic image formed thereon in an amount effective to desensitize said non-image area.

Method for desensitizing offset printing plates

The present invention is intended to provide a cyanless treating liquid for use in offset printing which has an intense desensitizability, is capable of rapidly forming a firm hydrophilic film, is free from deterioration of the efficiency thereof when subjected to light or heat, and poses no problem of public nuisance.

Aqueous treating liquid for use in offset printing

The present invention provides a treating liquid for use in treating offset masters which treating liquid consists essentially of ferrocyanate, water-soluble phosphate and a specific polymer or copolymer. By the use of this treating liquid, the durability of offset masters in printing can be remarkably enhanced.

Growing community of inventors

Tokyo, Japan

Hazime Machida