Fuji Photo Film Company, Limited

Tadao Toyama

Keisuke Shiba

Kesanao Kobayashi

Sho Nakao

Keiji Akiyama

Kenji Kunichika

Hiroshi Matsumoto

Masayuki Iwasaki

Hisao Ohba

Koji Tamoto

Akira Nagashima

Susumu Yoshida

Mitsuru Koike

Hidefumi Sera

Nobuyuki Kita

Keitaro Aoshima

Hisashi Hotta

Noriaki Watanabe

Hiroshi Misu

Teruo Nagano

Masaru Watanabe

Haruo Nakanishi

Masasi Ogawa

Akinobu Koike

Nobuyuki Nishimiya

Hitoshi Hagiwara

Atsushi Sakamoto

Masahiro Nishida

Norio Hishiki

Masanori Imai, Deceased

Harumasa Kitago

A method of development is disclosed, wherein printing plate precursors capable of being exposed with an infrared laser can be developed over a prolonged period without causing image defects, etc. The method comprises conducting the development of a photosensitive lithographic printing plate precursor using an automatic developing apparatus having a substantially closed developing tank in which a developing solution is introduced and a conveying means for conveying the plate precursor disposed within the developing tank.

Method of developing photosensitive lithographic printing plate precursor

Provided are a developer suitable for both positive working and negative working photosensitive lithographic printing plates for lithography and a replenisher thereof which comprise as a development stabilizer at least one compound selected from the group consisting of sugars, oximes, phenols and fluorinated alcohols in a proportion of at least 0.01 mole/l and have their pH values in the range of 11.0 to 13.5 by containing an alkali agent and a developer for photosensitive lithographic printing plates which comprises (1) a compound represented by formula (A) or (B) described in the present specification, (2) at least one compound selected from the group consisting of phenols, sugars, oximes and fluorinated alcohols which have buffering effect in the pH range of 11.5 to 13.5 and (3) a specific alkali agent, and has a pH of 11.5 to 13.5.

Method of preparing a lithographic printing plate using a developer

A presensitized plate for use in making a lithographic printing plate comprises a substrate; a photosensitive layer and a mat layer whose projections have an average diameter of not more than 100 .mu.m, an average height of not more than 10 .mu.m and whose coated amount ranges from 5 to 200 mg/m.sup.2, the photosensitive layer and the mat layer being applied onto the upper surface of the substrate; and a coating layer of an organic polymeric compound having a glass transition point of not less than 20.degree. C. and a thickness ranging from 0.01 to 8.0 .mu.m, the coating layer being applied onto the back face of the substrate. The presensitized plate makes it possible to solve the problem of the formation of scratches and the adhesion of the photosensitive layer to the back face of the PS plate even when a large number of PS plates are transported and/or stored while putting them in piles without sandwiching the PS plate between interleaves. The coated layer applied to the back face of the PS plate is tough and shows good adhesion to the substrate and is not peeled off during handling, development processing and printing operations.

Presensitized plate for use in making lithographic printing plate

A method for preparing a lithographic printing plate comprises imagewise exporting a PS plate comprising an aluminum substrate having an anodized layer and a light-sensitive layer applied on one side of the substrate and then developing the PS plate with a developer comprising an aqueous solution of an alkali metal silicate, while compensating changes in the developer due to the development of the PS plate by supplementing, to the developer, a replenisher comprising an aqueous solution of an alkali metal silicate, wherein the PS plate is provided with a coating layer containing an organic polymeric compound on the back face and the replenisher is an aqueous solution of an alkali metal silicate having a ratio: [SiO.sub.2 ]/[M.sub.2 O] (wherein [SiO.sub.2 ] means molar concentration (mol/l) of SiO.sub.2 and [M.sub.2 O] is molar concentration (mol/l) of oxide M.sub.2 O of an alkali metal (M)) ranging from 0.3 to 1.0 and an SiO.sub.2 content ranging from 0.5 to 4.0% by weight. The method makes it possible to substantially reduce the amount of the developer to be replenished, does not cause any formation of insolubles even if a great deal of PS plates are processed over a long time period and thus stable developing treatment can be carried out.

Method for preparing lithographic printing plate

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.

PS plate and method for processing same

A method for processing a photosensitive copying material comprises the steps of imagewise exposing to light a photosensitive copying material which comprises in order (i) a first photosensitive organic coating layer whose solubility in a developer varies through irradiation with light rays and (ii) a second organic coating layer containing a water-insoluble and organic solvent-soluble polymeric compound having an film-forming ability and then developing the imagewise exposed copying material, wherein the imagewise exposed material is dipped in the developer and then water-washed to remove the first and second organic coating layers on non-image portions. According to this method, the ability of the developer to process photosensitive copying materials is substantially improved, the amount of the waste liquor can substantially be reduced and a problem of environmental pollution can effectively be solved.

Method for processing photosensitive copying materials

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:

Presensitized plate having anodized aluminum substrate, hydrophilic

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 4.0% by weight on the basis of the total weight of the developer to remove the unexposed portion of the light-sensitive layer. The method for preparing lithographic printing plate makes it possible to treat both negative- and positive-working presensitized plates with a single developer and a single automatic developing machine and can provide a lithographic printing plate having excellent printing durability and free of background contamination. Moreover, the replenisher for developer of the present invention permits repeated development process over a long time period without deteriorating the developability thereof and makes it possible to perform developing process without accompanying any formation of deposits due to the light-sensitive resin components at the bottom of a developing bath.

Method for developing presensitized plate for use in making lithographic

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:

Method of making lithographic printing plate

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.

Method for manufacturing lithographic printing plates

A desensitizing gum lithographic plate finisher comprises water-soluble starch modified with urea-phosphoric acid containing 0.01 to 3% by weight of bound phosphorus and having a viscosity determined on 20% by weight aqueous solution at 30.degree. C. ranging from 15 to 300 cps. The plate finisher can also be used as an aqueous phase of an emulsion type plate finisher. The finisher has high desensitizing ability and excellent low temperature storability and does not cause any reduction in the ink receptivity of image areas of lithographic printing plates.

Desensitizing gum lithographic plate finisher

Disclosed is a method for the manufacture of a lithographic printing plate where a photosensitive lithographic printing plate precursor is imagewise exposed, a determined about of a developer is supplied to the exposed surface and the developer is the disposed of. A surfactant is added to the developer so that the surface tension of the developer is about 50 dyne/cm or less at 25.degree. C. By the addition of the surfactant, a stable and economical development of an exposed plate is possible with a small amount of the surfactant-containing developer.

Method for manufacture of lithographic printing plate with disposable

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.

Developing method for photosensitive material

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.

Desensitizing gum for planographic printing plates

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.

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Shizuoka, Japan

Tadao Toyama