Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/004—Photosensitive materials
  • G03F7/06—Silver salts
  • G03F7/063—Additives or means to improve the lithographic properties; Processing solutions characterised by such additives; Treatment after development or transfer, e.g. finishing, washing; Correction or deletion fluids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
  • B41N1/00—Printing plates or foils; Materials therefor
  • B41N1/12—Printing plates or foils; Materials therefor non-metallic other than stone, e.g. printing plates or foils comprising inorganic materials in an organic matrix
  • B41N1/14—Lithographic printing foils

Definitions

• the present invention relates to planographic printing forms.
• planographic printing which in principle is based on the different behaviour of image and non-image areas of the printing surf-ace zones with respect to water and greasy ink, it is usual to employ treating baths or Fixagen and weakly acid wetting agents which usually contain phosphoric acid. This applies more especially to printing with offset printing machines. If it is desired to avoid changing the wetting system or the wetting agent on the machine, the preparation of printing plates which have a surface consisting of a hydrophilic but water-insoluble coating material consequently presupposes that tone-free impressions can be made from such layers in the weakly acid pH range of.4 to 7.
• gelatine is not very suitable for this purpose, since on the one hand this shows a very small degree of swelling and thus only a small degree of water conduction during printing in the vicinity of the isoelectric point, which is just in the said pH range of 4 to 7.
• the gelatine is always made more or less strongly hydrophobic.
• gelatine layers Compared with other hydrophilic colloids, such for example as carboxymethyl cellulose hardened with heavy metal salts, gelatine layers nevertheless have the advantage of being resistant to alkali and consequently suitable for carrying out photographic processes which involve an alkali development.
• printing foils With printing foils, the ink-receiving images of which are produced photographically, a coating with IgeI-atine as hydrophilic water-conducting colloid is consequently preferrcd.
• Such printing plates have, for example, been proposed in German Patents Nos. 1,011,280; 1,058,844 and 1,064,343 and also in our copending United States patent application Serial No. 815,816. On printing with these printing plates, it has proved to be difiicult to obtain absolutely tone-free prints with wetting agents in the said pH range of 4 to 7, especially when the machine is further soiled by paper dust and the like.
• the partially neutralised hydro fluosilicic acid can be added to the gelatine prior to casting or can be introduced into the gelatine layer disposed on a support by means of an aftertreatment bath.
• this aftertreat-ment bath can be preceded or followed by a treatment of the gelatine layer with other baths, such for example as hardening baths, solutions which contain development nuclei (if desired also silver halide solvents) for the production of silver images by the silver salt diffusion process, and others.
• other baths such for example as hardening baths, solutions which contain development nuclei (if desired also silver halide solvents) for the production of silver images by the silver salt diffusion process, and others.
• Basic compounds the cations of which form watersoluble silicates, such for example as the hydroxides and carbonates of lithium, sodium and ammonium, are suitable for the neutralisation of the fluosilicic acid.
• hydro fiuosil-icic acid neutral-ised to pH of 5.0 to 6.5 is used as a 0.5 to 10 percent, preferably 1 to 5 percent, aqueous solution.
• deposits can form with the partial neutralisation to the said pH range of 5 to 6.5, and these deposits are filtered off before using the solution.
• Example 1 A paper sheet having wet-strength properties and weighing about g. per square metre is coated in a first working step with :a gelatine solution having the following composition:
• aqueous gelatine solution (30 percent) 170 parts of a 7 percent hydro fiuosilicic acid neutralised with soda to a pH of 5.5 to 5.8 and filtered 30 parts or" aqueous sodium thiosulphate solution (50 percent) 10 parts of aqueous saponin solution (7.5 percent)
• the pH value of the complete solution is 5 .5.
• This solution is diluted to such a degree with a 3.5 percent hydro fluosilicic tacid also neutralised with soda to a pH of 5.5 to 5.8 and filtered, so that the gelatine coating is 2 to 4 gjm. under the given casting conditions.
• the cast layer is dried at 70 to 80 C.
• the gelatine layer is then treated with the following aqueous solution:
• Example 2 A paper support as described in Example 1 is cast in a first working step with a gelatine solution having the following composition:
• the gelatine layer has cast thereon an aqueous solution with the following composition:
• the layer has cast thereon the following aqueous solution:
• the layer finally has coated thereon the following aqueous solution:
• the paper coated in this way is stored for 8 days for completely hardening the gelatine layer.
• Example 3 A paper support as described under 1 is coated in one working step with a gelatine solution having the following composition:
• aqueous gelatine solution 15 percent
• 25 parts of aqueous 1 percent solution of colloidal silver sulphide parts of aqueous sodium thiosulphate solution 50 percent
• 5 parts of aqueous saponin 7.5 percent
• the solution is diluted with water until a gelatine coating of 2 to 4 g./m. is obtained under the given casting conditions and the cast layer is dried at 120 C.
• the layer has applied thereto the following aqueous solution:
• Example 4 A paper support as described in Example 1 is coated in a first working step with the following gelatine solution:
• aqueous gelatine solution 15 percent
• aqueous saponin solution 7.5 percent
• the solution is diluted with water until a layer coating of about 4 to 6 g/rn. is obtained and the layer is dried at to C.
• the layer has the following aqueous solution cast thereon:
• the layer has the following aqueous solution cast thereon:
• tone-free impressions can be produced from the foils of the paper coated in this Way, using the test conditions of Example 1, this being in contrast to a sample H1 which the third casting (ill) has been omitted.
• Example 5 A paper support as described in Example 1 is treated in four Working steps as in Example 4, except that ammonium carbon-ate is replaced by lithium carbonate for the partial neutralisation of the fluosilicic acid in the third working step (III). The results are analogous to those set out in Example 4.
• the amount thereof may be varied in wide limits. Preferably this amount is so chosen that to 50 g. of neutralised hydro fluosilicic acid are present per 100 g. of gelatine.
• sodiumthiosulphate there may also be added other silver halide solvents to the gelatine solution, such as other alkali metal thiosulphates, ammonium thiosulphate, alkaline earth thiosulphates or mixtures thereof, as for instance lithium-, calcium-, barium-,
• the amount of these thiosulphates may vary within about 1 to 50 g. per 100 g. of gelatine.
• development nuclei there can be incorporated into the gelatine layer besides silver sulfide all other nuclei which are used in transfer layers for the silver salt diffusion process, including colloidal noble metals, such as colloidal silver or colloidal gold, and heavy metal sulfides such as zinc sulfide, cadmium sulfide or lead sulfide, these development nuclei being preferably applied in amounts of about 0.2 to 2 g. per 100 g. of gelatine.
• colloidal noble metals such as colloidal silver or colloidal gold
• heavy metal sulfides such as zinc sulfide, cadmium sulfide or lead sulfide
• sion layer from said reception layer and hardening said reception layer for planographic printing, the improvement consisting of contacting the gelatin of said reception layer with an aqueous hydrofiuosilicic acid solution having a pH value of 5 to 6.5.
• gelatin of said reception layer is a cast layer and said aqueous hydrofluosilicic acid solution is added to the gelatin prior to casting.
• hydrofiuosilicic acid solution has a concentration of from 0,5 10 percent of hydrofluosilicic acid.
• a process according to claim 1 wherein the pH value of said hydroiiuosilicic acid solution is adjusted by the addition of a compound selected from the class consisting of sodium hydroxide, sodiumcarbcnate, lithium hydroxide, lithium carbonate, ammonium hydroxide and ammonium carbonate.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Printing Plates And Materials Therefor (AREA)

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Publications (1)

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Family Applications (1)

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Cited By (2)

Citations (7)

• 0
  • NL NL242754D patent/NL242754A/xx unknown
  • BE BE582225D patent/BE582225A/xx unknown
• 1958
  • 1958-09-02 DE DEA30211A patent/DE1098813B/de active Pending
• 1959
  • 1959-08-26 US US836073A patent/US3089770A/en not_active Expired - Lifetime
  • 1959-09-02 GB GB29941/59A patent/GB883843A/en not_active Expired
  • 1959-09-02 FR FR804101A patent/FR1234059A/fr not_active Expired

Patent Citations (7)

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