摘要:
A light-sensitive planographic printing plate comprising a layer of a photo-polymerizable composition provided on at least one side of a base, wherein said photo-polymerizable composition comprises:(A) a polymer having at least one group represented by the general formula (I) ##STR1## wherein R.sub.1 to R.sub.5 each represent a member selected from the group consisting of a hydrogen atom, a halgen atom, a carboxyl group, a sulfo group, a nitro group, a cyano group, an amido group, an amino group and a substituted or unsubstituted alkyl group, aryl group, alkoxy gruop, aryloxy group, alkylamino group, arylamino group, alkylsulfonyl group and arylsulfonyl group and Z represents an oxygen atom, a sulfur atom, NH or NR, wherein R represents an alkyl group; and a carboxyl group on the side chain;(B) a monomer or oligomer having at least two polymerizable ethylenically unsaturated double bonds;(C) a photo-polymerization initiator, and(D) a diazo resin.
摘要:
A presensitized printing plate which has a photopolymerizing composition layer provided on at least one side of a support, with the photopolymerizing composition being constituted with (A) a polymer containing in its side chains groups represented by the following general formula (I) and carboxylic groups: ##STR1## (wherein R.sub.1 to R.sub.5 each represents a hydrogen atom, a halogeno group, a carboxyl group, a sulfo group, a nitro group, a cyano group, and amido group, an amino group, or an unsubstituted or a substituted alkyl, aryl, alkoxy, aryloxy, alkylamino, arylamino, alkylsulfonyl or arylsulfonyl group; and Z represents an oxygen atom, a sulfur atom, --NH-- or --NR-- (R=alkyl)), (B) a monomer or an olygomer having at least two polymerizable ethylenically unsaturated double bonds, and (C) a photopolymerization initiator.
摘要:
A desensitizing gum containing water-soluble carboxy alkylated starch wherein the carboxy alkyl group number of said carboxy alkylated starch is from 0.03 to 0.5. The desensitizing gum has desensitizing ability comparable to gum arabic.
摘要:
This invention provides a developing method for photosensitive materials, in particlar for a positive photosensitive lithographic printing plate, which enables an efficient development with minimum consumption of the developing liquid. The developing method of the present invention comprises the steps of: conducting a preparatory development by applying a developing liquid to an exposed photosensitive layer of a photosensitive material, the developing liquid being supplied in an amount of necessary for each developing cycle; removing the developing liquid; discarding the developing liquid; and again applying a developing liquid to the photosensitive material to complete the development.
摘要:
A method for forming an image on a light-sensitive material with a light-sensitive layer composed of a photopolymerizable composition, and an apparatus for carrying out the method are described. This method comprises exposing imagewise, heating, and developing a number of light-sensitive materials while the time interval between the heating and developing steps is maintained at a definite level. Changes in sensitivity of the light sensitive material are prevented and images of high sensitivity are obtained.
摘要:
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. Moreover, the PS plate does not suffer from a problem of contamination of the back face due to adhesion of lipophilic substances such as a developing ink.
摘要:
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.2 is the same as that defined above, and a positive-working light-sensitive layer comprising an o-quinondiazide compound and developing the exposed plate with an aqueous solution which contains at least one compound selected from the group consisting of alkali metal salts and ammonium salts of inorganic acids other than silicic acid, alkali metal hydroxides, ammonium hydroxide and water-soluble organic amine compounds. This method can provide a lithographic printing plate having good resistance to contamination and high printing durability. Further, even if developing treatment is performed for a long time with an automatic developing machine in this method, deposits and sludge are not produced.
摘要:
A method for manufacturing lithographic printing plates which comprises developing a presensitized plate for use in making lithographic printing plates imagewise opposed to light with an alkaline developer utilizing an automatic developing machine and then treating the developed presensitized plate with a finisher, wherein an initial pH of the finisher ranges from 2 to 8 and a pH of the finisher is controlled during running in proportion to concentration of the developer included in the finisher. The method makes it possible to prevent the formation of gel-like insoluble matters in the bath for treatment with the finisher due to the presence of the developer carried over from a developing bath and to stably process a large amount of lithographic printing plates over a long time period.
摘要:
A desensitizing gum comprising an aqueous solution containing at least one of film-forming starches modified with phosphoric acid or its derivatives. The desensitizing gum has good desensitizing ability and can easily be removed from a printing plate finished therewith after prolonged storage.
摘要:
A photosensitive lithographic printing plate precursor which has a camera speed together with all the advantageous features inherent to positive type, conventional PS plates is disclosed. On an aluminum support having a hydrophilic surface, one provides first a positive type non-silver photosensitive layer capable of forming an oleophilic image, and then superposes thereon an unfogged positive type internally sensitized silver halide photographic emulsion coating.