Mitsubishi Paper Mills Limited

Satoshi Shimonodan

Motozo Yamano

Akira Furukawa

Takashi Miyazaki

Etsuji Tanaka

There is disclosed a process for making a lithographic printing plate, which comprises subjecting a lithographic printing material having at least a silver halide emulsion layer and a physical development nuclei layer on a support and having a sensitivity at a wavelength of 400 nm to 440 nm of 20 &mgr;J/cm or less, and having substantially no sensitivity at a wavelength of 450 nm or longer to scanning exposure by a scanning type exposure device on which a violet laser diode is mounted, and then subjecting to developing treatment.

Process for making lithographic printing plate

Disclosed is a lithographic printing plate having a silver halide emulsion layer and a layer containing physical development nuclei on a support, the improvement wherein a water-soluble polymer having a structural unit represented by the formula (I): ##STR1## wherein R.sup.1 represents H or alkyl; Q represents divalent linking group; R.sup.2 represents divalent linking group or direct bond; and A represents a functional group represented by the formula: --S--C(.dbd.N--R.sup.4)--NH--R.sup.3, --Z--X(.dbd.Y)--(R.sup.5).sub.m or --W--(SH).sub.n where respective substituents are defined in the specification is contained in the layer containing physical development nuclei.

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Tokyo, Japan

Satoshi Shimonodan