Abstract: A heat-sensitive precursor of lithographic printing plates, which comprises a hydrophilic layer provided on a substrate having an ink-receptive surface or coated with an ink-receptive layer; the printing plate precursor further having a water-soluble overcoat layer on the hydrophilic layer, and the hydrophilic layer being a three-dimensionally cross-linked hydrophilic layer, the heated area of that is easily removed by a fountain solution or ink when subjected to printing operations.

Abstract: A heat-sensitive lithographic printing plate precursor which comprises a substrate having thereon an anodic oxidation layer, with the printing plate precursor comprising a hydrophilic layer containing at least one kind of fine particles selected from the group consisting of heat-fusible hydrophobic thermoplastic fine particles, finely divided polymers having thermally reactive functional groups and microcapsules in which compounds having heat-reactive functional groups are encapsulated, and with the anodic oxidation layer having a surface over which micropores having an average pore size of 6 to 40 nm are uniformly distributed.

Abstract: A lithographic printing plate precursor is disclosed, which comprises an image-forming layer which contains a hydrophilic resin, an acid precursor and at least one component selected from fine particles containing a compound having a vinyloxy group and microcapsules containing a compound having a vinyloxy group, on a hydrophilic support, which can be development processed on a printing machine.

Abstract: A hydrophilic layer and an overcoat layer are provided in this order on a heat-sensitive layer having an ink receiving surface, so as to form an original (plate) for a lithographic printing plate. The overcoat layer can be removed during printing. A system capable of forming an inorganic hydrophilic matrix by sol-gel conversion is provided in the hydrophilic layer. Adhesion between the heat-sensitive layer and the hydrophilic layer decreases in a heated region through image processing. Emulsion ink is supplied to the plate surface during printing, whereby the overcoat layer and the hydrophilic layer at an image portion are removed with a hydrophilic component of the emulsion ink. Thus, with a heat-sensitive original that can be subjected to heat-mode prepress using laser exposure, good printed matter can be stably obtained, irrespective of balance between image and non-image portions, without using wetting water.

Abstract: A photosensitive lithographic printing plate in which press life, deletion performance, photosensitive layer removability and image reproducibility are compatible with one another, while retaining scumming prevention performance, which comprises an aluminum support hydrophilized after anodic oxidization, an intermediate layer provided thereon containing an alkali-soluble polymer adjusted in a number-average molecular weight (Mn) to the range of 300 to 5,000 by using an initiator in combination with a chain transfer agent in radical polymerization, and a photosensitive layer provided on the intermediate layer.

Abstract: A positive working photosensitive lithographic printing plate comprising an aluminum substrate and a positive working photosensitive layer, the aluminum substrate having been anodized and rendered water-wettable, wherein an intermediate layer containing a polymer comprising (A) a unit interacting with an alumina layer and (B) a unit interacting with a water-wettable layer is provided between the aluminum substrate and the photosensitive layer. The photosensitive layer and the water-wettable aluminum substrate have good adhesion so that the printing plate has a satisfactory press life.

Abstract: Disclosed are (i) a positive-working photosensitive composition containing (a) a polymer having at least 60 mol % structural units represented by formula (1): ##STR1## wherein A represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms; X represents --CO-- or --SO.sub.2 --; Y represents --CO--R.sub.1 or --SO.sub.2 --R.sub.1, where R.sub.1 represents an alkyl group, a substituted alkyl group wherein the substituent on the substituted alkyl group is a halogen atom, an aryl group, an amido group, an alkoxy group or an alkoxycarbonyl group, an unsubstituted aromatic group, or a substituted aromatic group wherein the substituent on the substituted aromatic group is a halogen atom, an alkyl group, an alkoxy group having 1 to 10 carbon atoms, an amido group or an aryl group, provided that at least one of X and Y contains --SO.sub.

Abstract: A communication system includes a master station connected to a telephone line network and a plurality of remote stations for transmitting and receiving digital data to and from the master station through a radio transmission line. Among the master station and the remote stations, one channel is divided into a plurality of slots. One of the plurality of slots is assigned as a control slot to transmit and receive data in a time-division manner. The master station transmits control data to the remote stations by the control slot. The master station transmits control data by the control slot at every predetermined period and also transmits data concerning a communication by the control slot during a predetermined period.

Abstract: A photosensitive lithographic printing plate which provides a wide range of proper conditions for development, high impression capacity, a flexible film sufficient in adhesion to a support and excellent processing suitability with a weakly alkaline developer (pH 12.5 or less) is disclosed. The photosensitive lithographic printing plate comprises a support and a photosensitive layer provided thereon, wherein the photosensitive layer is formed from a photosensitive composition containing at least a two-equivalent coupler residue-containing compound and a photosensitive compound or a photosensitive mixture acting as a positive type.

Abstract: A PS plate comprises an aluminum substrate having anodized layers on both sides, a photosensitive layer on one side of the substrate and a coating layer of a metal oxide obtained by hydrolyzing and polycondensing an organic or inorganic metal compound on the side of the substrate opposite to that carrying the photosensitive layer. The PS plate is processed by a method comprising the steps of imagewise exposing it to light and then developing the imagewise exposed plate with an alkali aqueous solution containing an alkali metal silicate and having a pH of not less than 12. The PS plate and the method for processing the same permit substantial reduction of the amount of a replenisher for development to be supplemented and ensure a stable processing of the plate over a long time period without accompanying formation of insolubles in a developer. The PS plates never cause adhesion and peeling off of the photosensitive layers even when they are put in stacks.

Abstract: A PS plate comprises an aluminum plate which is surface-roughened and then anodized so that the amount of an anodized layer formed is not less than 1.0 g/m.sup.2 ; a hydrophilic layer which is applied onto the anodized layer and which comprises at least one compound selected from the group consisting of:(A) substituted or unsubstituted aliphatic or aromatic phosphonic acids having one or two phosphonic acid residues in the molecule and salts thereof; and(B) substituted or unsubstituted aliphatic or aromatic phosphinic acids having one or two phosphinic acid residues in the molecule and salts thereof,wherein the substituent of the compounds (A) and (B) being at least one member selected from the group consisting of hydroxyl, alkoxy, aryloxy, carboxyl, alkyl, aryl, allyl, acyl, acyloxy, nitro and cyano groups and halogen atoms; and a layer of a positive-working light-sensitive composition formed on the hydrophilic layer.

Abstract: A method for preparinq a lithographic printing plate comprising the steps of imagewise exposing, to light, a negative-working presensitized plate for use in making a lithographic printing plate which comprises a substrate provided thereon with a light-sensitive layer comprising an aromatic diazonium compound having at least one member selected from the group consisting of carboxyl groups, phenolic hydroxyl groups, sulfonic acid residues, sulfinic acid residues and phosphorus atom-containing oxyacid residues and developing the imagewise exposed presensitized plate with a developer which comprises an aqueous solution of an alkali metal or ammonium silicate having a ratio: [SiO.sub.2 ]/[M], wherein [SiO.sub.2 ] and [M] represent the molar concentrations of SiO.sub.2 and the alkali metal or ammonia in the developer respectively, ranging from 0.15 to 0.75 and an SiO.sub.2 content ranging from 1.0 to 4.

Abstract: A method of making a lithographic printing plate comprises the steps of imagewise exposing to light a presensitized plate which comprises a hydrophilized substrate provided thereon with an organic layer comprising at least one compound selected from the group consisting of substituted or unsubstituted aliphatic or aromatic compounds represented by the following general formula:R.sup.1 (PO(OH.sub.2).sub.n (I) orR.sup.1 (PO(OH)(R.sup.2)).sub.n (II)wherein n is 1 or 2, if n is 1, R.sup.1 and R.sup.2 each represents a substituted or unsubstituted alkyl, alkoxy, aryloxy, aryl, acyl or acyloxy group and if n is 2, R.sup.1 represents a substituted or unsubstituted alkylene or arylene group and R.sup.

Abstract: A developer composition for presensitized plates for use in making lithographic printing plates comprises water, an alkali silicate and at least one compound having at least one aryl group, at least one oxyalkylene group and at least one sulfate ester group or sulfonic acid group. The composition is excellent in developing stability and processability. It is less foamable and seldom generates deposits even when it is deteriorated. Moreover, the composition makes it possible to develop both positive- and negative-working PS plates.

Abstract: A developer composition comprises an aqueous alkaline solution which contains at least one alkali-soluble mercapto compound and/or thioether compound. The developer composition is excellent in developing properties and provides lithographic printing plates which do not cause background contamination of non-image areas during printing, when it is used in developing PS plates. It can be stored for a long time. The developer composition further makes it possible to develop both negative and positive working PS plates if its pH value is not less than 12.

Abstract: A photosensitive recording material comprising (a) a substrate having a hydrophilic surface, (b) an undercoating layer comprising at least one compound having at least one functional group selected from the group consisting of thiol, thioether and disulfide groups, and (c) a photosensitive layer comprising at least one diazonium compound and a high molecular weight binder compound which is insoluble in water and soluble in aqueous alkaline solution. The resulting developed plate yields no background contamination in printing process.

Abstract: A positive-working light-sensitive composition is herein disclosed, which comprises a mixed organic solvent consisting of (i) at least one organic solvent having a boiling point of at least 40.degree. C. and less than 100.degree. C., (ii) at least one organic solvent having a boiling point of at least 100.degree. C. and less than 140.degree. C., and (iii) at least one organic solvent having a boiling point of at least 140.degree. C. and less than 210.degree. C.; or (a) at least one organic solvent as defined in the above item (i), (b) at least one organic solvent as defined in the item (ii), (c) at least one organic solvent having a boiling point of at least 210.degree. C.