Ricoh Company, Ltd.

Makoto Kunikane

Masaakira Umehara

Michiharu Abe

Kiyoshi Taniguchi

Hideaki Oba

Koji Uji-Ie

Tsutomu Sato

Kiyoshi Tanikawa

Yutaka Ueda

Akiyoshi Yasumori

Tetu Yamamuro

This invention relates to an optical information recording medium, characterized in that on a substrate there is applied a coloring matter film chemically inert to said substrate, said coloring matter film having an extinction coefficient of at least 1.

Optical information recording medium

An optical information recording medium comprising a substrate and a recording layer superimposed on said substrate, said recording layer comprising a reflective layer in which metal particles with a particle diameter of 1500.ANG. or less have been distributed closely and a light absorptive layer in which metal compounds and a very small amount of metal particles with a particle diameter of 200-2000.ANG. have been dispersed unformly or substantially uniformly in the volume ratio of 1-30% in a resin.

An optical information recording medium comprises a transparent or opaque substrate and a cyanine coloring matter-containing thin coloring matter layer formed on said substrate. This recording material is adapted for laser beam reading and writing.

A photo-sensitive and heat-sensitive composition consisting essentially of (a) a photooxidant, (b) a color-generator generating color when oxidized, (c) an acid promoting said color generation, (d) a cobalt (III) complex, (e) a photoreductant, (f) a hydrogen donator and (g) a chelating agent consisting of a dioxime compound having the general formula: ##STR1## (where n is an integer of 0 to 3, and R.sub.1 and R.sub.2 can each represent an alkyl, aryl or aralkyl group), and a recording element using the same.

Photo-sensitive and heat-sensitive composition and recording element

A photo-sensitive and heat-sensitive composition consisting essentially of (a) a photooxidant, (b) a color-generator generating color when oxidized, (c) an acid promoting said color generation, (d) a cobalt (III) ammine and/or amine complex, (e) a photoreductant, (f) a hydrogen donator, (g) at least one kind of chelating agent selected from dioxime chelating agents having the general formula (I): ##STR1## (wherein n is an integer of 0 to 3, and R.sub.1 and R.sub.2 can each represent an alkyl, aryl or aralkyl group) and diantipyrylmethane chelating agents having the general formula (II): ##STR2## (wherein R.sub.3, R.sub.4, R.sub.5, R.sub.3 ', R.sub.4 ' and R.sub.5 ' can each represent a hydrogen atom and an alkyl or aryl group, and R.sub.6 and R.sub.7 can each represent a hydrogen atom and an alkyl, substituted or nonsubstituted aryl or aralkyl group), and (h) at least one kind of stabilizer selected from noble metal complexes, organic oxidants and organic acids, and a recording element using the same.

A photo-sensitive and heat-sensitive composition consisting essentially of a leuco-pigment; a hydrogen donator; a photo-reductant which, when exposed to a visible light, produces a reducing agent by the action of said hydrogen donator coexisting therewith; a photooxidant which, when exposed to an ultraviolet ray, causes said leuco-pigment coexisting therewith to generate color and simultaneously, when reacted with said reducing agent, is deprived of its own oxidizing ability; and a cobalt complex which reacts with the reducing agent in amplifying manner to thereby suppress the reaction of a color-forming system, and a recording element using the same.

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Chigasaki, Japan

Makoto Kunikane