Process for the production of printing plates

Claim 2

In a process for producing a lithographic printing plate from a light-sensitive element comprising a support with a hydrophilic surface, a non-silver light-sensitive layer provided on the support which forms a water-insoluble lipophilic image and a gelatino-silver halide light-sensitive emulsion layer on the non-silver light-sensitive layer which comprises the steps of: (a) imagewise exposing the light-sensitive element; (b) developing the gelatino-silver halide light-sensitive emulsion layer to form a silver image; (c) exposing the non-silver light-sensitive layer to radiation to which it is sensitive; (d) washing out the developed gelatino-silver halide light-sensitive emulsion layer; and (e) developing the non-silver light-sensitive layer to remove either exposed area or unexposed area of said non-silver light-sensitive layer thereby obtaining a lithographic plate comprising the water-insoluble lipophilic image, the improvement where the washing-out of step (d) is carried out in the presence of a proteolytic enzyme.

Claim 3

The process according to claim 1, wherein said proteolytic enzyme is present in the gelatino-silver halide light-sensitive layer.

Claim 4

The process according to claim 1, wherein said proteolytic enzyme is present in the processing liquid for the washing-out.

Claim 5

The process according to claim 1, wherein said non-silver light-sensitive layer comprises an o-naphthoquinonediazide compound and an alkali-soluble resin.

Claim 6

The process according to claim 4, wherein said gelatino-silver halide light-sensitive emulsion layer is provided directly on said non-silver light-sensitive layer and a water-soluble lipophilic resin is dispersed in a fine particle form in the emulsion layer.

Claim 7

The process according to claim 5, wherein said proteolytic enzyme is present in the processing liquid for the washing-out.

Claim 8

The process according to claim 6, wherein said processing liquid for the washing-out comprises an aqueous solution containing 0.001 to 10% by weight of a proteolytic enzyme.

Claim 9

The process according to claim 7, wherein said washing out of step (d) is carried out using said processing liquid at a temperature of from 20° C. to 60° C. for a processing time of 10 to 60 seconds.

Claim 10

The process according to claim 7, wherein said washing out of step (d) is carried out using said processing liquid at a temperature of from 30° C. to 50° C. for a processing time of 10 to 30 seconds.

Claim 11

A process for producing a lithographic printing plate from a ligh-sensitive element comprising a support having a hydrophilic surface, a non-silver light-sensitive layer on the support which forms a water-insoluble lipophilic image and a gelatino-silver halide light-sensitive emulsion layer on the non-silver light-sensitive layer, comprising the steps of: (a) imagewise exposing the element to light, to which the gelatino-silver halide light-sensitive layer is sensitive, in order to form a latent image on the gelatino-silver halide light-sensitive emulsion layer; (b) developing the element to form a silver image on the gelatino-silver halide light-sensitive emulsion layer; (c) exposing the element to radiation, to which the non-silver light-sensitive layer is sensitive, in order to form the water-insoluble lipophilic image on the non-silver light-sensitive layer; (d) washing the element in an aqueous solution containing 0.001% to 10% by weight of proteolytic enzyme at a temperature of from 20° C. to 60° C. for 10 to 60 seconds in order to wash out the developed gelatino-silver halide light-sensitive emulsion layer; (e) developing the non-silver light-sensitive layer to remove either exposed area or unexposed area of said non-silver light-sensitive layer thereby obtaining a lithographic plate comprising the water-insoluble lipophilic image.

Claim 12

A process for producing a lithographic printing plate from a ligh-sensitive element comprising a support having a hydrophilic surface, a non-silver light-sensitive layer on the support which forms a water-insoluble lipophilic image and a gelatino-silver halide light-sensitive emulsion layer on the non-silver light-sensitive layer, comprising the steps of: (a) imagewise exposing the element to light, to which the gelatino-silver halide light-sensitive layer is sensitive, in order to form a latent image on the gelatino-silver halide light-sensitive emulsion layer; (b) developing the element to form a silver image on the gelatino-silver halide light-sensitive emulsion layer; (c) exposing the element to radiation, to which the non-silver light-sensitive layer is sensitive, in order to form the water-insoluble lipophilic image on the non-silver light-sensitive layer; (d) washing the element in an aqueous solution containing 0.001% to 10% by weight of proteolytic enzyme at a temperature of from 20° C. to 60° C. for 10 to 60 seconds in order to wash out the developed gelatino-silver halide light-sensitive emulsion layer; (e) developing the non-silver light-sensitive layer to remove either exposed area or unexposed area of said non-silver light-sensitive layer thereby obtaining a lithographic plate comprising the water-insoluble lipophilic image.