Oji Paper Co., Ltd.

Agency of Industrial Science and Technology

Masahiro Yamana

Koji Sato

Hiroshi Ito

Masahiro Kamiya

Tsunehisa Shigetani

Masataka Ito

Kunihiro Ichimura

Takao Ayukawa

Tetsu Uesaka

An electrophotographic lithograph printing plate material having an enhanced sensitivity to laser rays, an excellent heat resistance and a low dark decay comprises an electroconductive, water-resistant substrate and an electrophotographic layer comprising a photoconductive zinc oxide, a resinous binder and a sensitizing dye material which comprises at least one compound (A) of the formula (I) and at least one compound (B) of the formula (II): ##STR1## wherein each of A.sub.1 and A.sub.2 represents a C.sub.5-7 polymethine group non-substituted or substituted with at least one substituent, for example, --Cl, the substituted polymethine group may have a cyclic structure, for example, of: ##STR2## each of from B.sub.1 to B.sub.4 is a divalent non-substituted or substituted, benzene or naphthalene group, each of from X.sub.1 to X.sub.4 is a S, Se, or O atom or a --C(CH.sub.3).sub.2 -- group, each of from R.sub.1 to R.sub.4 is a C.sub.1-5 alkyl group, each of M.sub.1 and M.sub.5 is a metal atom, organic base or hydrogen atom, each of Y.sub.1 and Y.sub.2 is an anion, and m and n is zero or 1 but when n= 1, m= 1 and when n= 0, m= 0 and --R.sub.3 COO group adjacent to the (M.sub.1).sub.m group in the formula (II) is anionic, the weight ratio of the compound (A) to the compound (B) being 3:1 to 20:1.

Electrophotographic lithograph printing plate material having a mixture

An electroghraphic lithograph printing plate material having an enhanced spectral sensitivity to semiconductor laser rays, comprises a electroconductive water-resistant support and electrophotographic layer formed on the support and comprising a photoconductive zinc oxide, a binder resin and a sensitizing dye material comprising (a) 30 to 99% by weight of a low adsorption sensitizing dye for which the zinc oxide exhibits a low adsorption rate of less than 90% and (b) 1 to 70% by weight of a high adsorption sensitizing dye for which the zinc oxide exhibits a high adsorption rate for 90% or more, the adsorption rate being measured by spectrophotometry.

Electrophotographic lithograph printing plate material

A support sheet for photographic paper having an enhanced resistance to curling, especially twist-curling, comprises a substrate paper sheet composed of a half stratum portion thereof at the face side of a surface on which a photographic emulsion layer will be formed and the other half stratum portion thereof at the back side of the opposite surface, and two polyolefin resin coating layers on the two surfaces of the substrate paper sheet, the substrate paper sheet having a resiliency satisfying the relationships (I) and (II):

Support sheet for photographic paper

A photosensitive resin emulsion composition comprising an aqueous emulsion of a film-forming resin and a protective colloid for said emulsion, wherein the protective colloid comprises at least one photosensitive saponified polyvinyl acetate derivative which is at least partially grafted onto the film-forming resin, and the photosensitive saponified polyvinyl acetate derivative comprises a backbone formed of saponified polyvinyl acetate and at least one photosensitive unit and at least one hydrophobic unit bonded to the backbone.

Growing community of inventors

Tokyo, Japan

Masahiro Yamana