Mitsubishi Paper Mills Limited

Shoji Yamada

Eiji Kanada

Yasuo Tsubai

Akira Tanaka

Toshiro Kondo

Takao Senga

Kozo Haino

Yoshikazu Takaya

Shoichi Horii

Kiyoshi Yamashita

Eiji Mathubara

Disclosed are a deletion fluid for offset printing plates which contains an S-triazine compound represented by the following general formula: ##STR1## (wherein R.sub.1 and R.sub.2 represent --SH or --OH and when either one of R.sub.1 or R.sub.2 is --SH, the other may be NHR wherein R is H or --R'---COOH wherein R' is an alkylene group or arylene group) and a method for deletion of undesired portion of images formed on an offset printing plate with said deletion fluid.

Deleting agents for printing plates and method for deletion

Surface treatment of lithographic printing plate which utilizes as ink receptive areas a photographically formed image silver per se or image silver halide per se is carried out in the presence of an organic compound having at least one mercapto or thione group and at least one hydrophilic group in the same molecule and an inorganic water-insoluble fine powder having a particle size of 0.1.mu. or less after imagewise exposure of a silver halide emulsion layer and processing thereof to develop an image, whereby ink receptivity, anti-staining property and printing endurance of the plate can be improved.

Method for treating lithographic printing plates

Method for making lithographic printing plates by silver salt diffusion transfer process is disclosed. That is, lithographic printing plates having excellent printing endurance are obtained by carrying out the diffusion transfer processing in the presence of a compound having the ring structure ##STR1## which may be present in at least one constitutive layer of the printing plate materials (photographic materials) used for making the printing plates or in the diffusion transfer processing solution.

Method for making a diffusion transfer lithographic printing plates with

In a silver halide photographic material, at least one mercapto complexing agent for silver salt is contained in at least one photographic constituting layer and at least one anion or betaine type cyanine sensitizing dye is contained in silver halide emulsion layer to improve photographic defects such as reduction of sensitivity, softening in tone, etc.

Silver halide photographic materials

Lithographic printing plates having high ink receptivity, suffuring no ink stains and having much improved printing endurance can be produced by silver complex diffusion transfer process from lithographic printing plate materials comprising a support having thereon at least both silver halide emulsion layer and physical development nuclei layer wherein the diffusion transfer processing is carried out in the presence of 2-mercaptobenzoic acid derivatives or, besides this 2-mercaptobenzoic acid derivatives, at least one compound selected from the group consisting of alkanolamines and cyclic imide compounds which may be contained in at least one layers of the lithographic printing plate materials and/or the diffusion transfer developing solutions.

Photographic material and diffusion transfer processing solution for

In production of lithographic printing plates by developing a photographic material comprising a support having thereon at least both silver halide emulsion layer and physical development nuclei layer by silver complex diffusion transfer process to form transfer silver to be used as ink-receptive portions of the lithographic printing plates, when the development is carried out in the presence of a cyclic imide compound (alone or in combination with sulfites, thiosulfates, thiocyanates or alkanolamines) as defined hereinafter, ink-receptivity of the transfer silver image portions and printing endurance of thus obtained printing plates are improved. Moreover, the non-image portions have no or substantially no stains.

Photographic material for production of printing plates and method for

An image-forming layer containing silver halide emulsion and a magenta coupler represented by the general formula: ##STR1## wherein R.sub.1 represents an alkyl group having 10 to 18 carbon atoms, R.sub.2 represents hydrogen atom or an alkyl group having 1 to 4 carbon atoms, X represents a halogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, Y.sub.1 represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, Y.sub.2 and Y.sub.3, which may be the same or different, represent hydrogen atoms or have the meaning assigned to Y.sub.1, and Z represents hydrogen atom or the atom or group which splits off by coupling.

Growing community of inventors

Nagaokakyo, Japan

Shoji Yamada