Photosensitive lithographic printing plate precursor and a method for preparing a printing plate therefrom
AssigneeFuji Photo Film Co., Ltd.
InventorKeisuke Shiba
Life of this patent
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Abstract
A photosensitive lithographic printing plate precursor and a method for the preparation of a lithographic printing plate is described, said precursor comprising a support, a non-silver photosensitive layer and a photographic silver halide emulsion coating, and exhibiting photographic camera speed and a printing durability equivalent to the conventional type presensitized plate due to the underlying non-silver photosensitive layer; the silver halide emulsion coating contains a compound represented by the formual (I) R.sup.1 NHNHCOR.sup.2 (I) in which R.sup.1 represents an aryl group and R.sup.2 represents hydrogen, an aryl group, or an aliphatic group.
Claims26
A photosensitive lithographic printing plate precursor comprising, in sequence, a support having a hydrophilic surface, a non-silver photosensitive layer capable of producing an oleophilic image, and a photographic silver halide emulsion coating,
- wherein said silver halide emulsion coating comprises silver halide grains with an average diameter not exceeding 0.7 micron and a compound represented by the formula (I)
- R.sup.1 NHNHCOR.sup.2 (I)
- wherein R.sup.1 represents an aryl group and R.sup.2 represents hydrogen, an aryl group, or an aliphatic group.
A method for preparing a lithographic printing plate comprising
- (a) imagewise exposing a photosensitive lithographic printing plate precursor comprising, in sequence, a support having a hydrophilic surface, a non-silver photosensitive layer capable of forming an oleophilic image, and a photographic silver halide emulsion coating,
- wherein said silver halide emulsion coating comprises silver halide grains with an average grain size not exceeding 0.7 micron and a compound represented by the formula (I)
- R.sup.1 NHNHCOR.sup.2 (I)
- wherein R.sup.1 represents an aryl group, and R.sup.2 represents hydrogen, an aryl group or an aliphatic group together with a poly(alkylene oxide) or a derivative thereof having a molecular weight of at least 600,
- (b) subjecting said exposed plate to a first development with a first developer containing a dihydroxybenzene reducing agent and free sulfite ions having a concentration of at least 0.18 mol/l,
- (c) fixing the developed photographic coating,
- (d) uniformly exposing the thus-processed plate to radiation to which said non-silver photosensitive layer is sensitive,
- (e) washing to remove said silver halide emulsion coating, and
- (f) processing the plate with a second developer capable of developing said non-silver photosensitive layer to remove either the exposed areas or unexposed area with the radiation of said non-silver photosensitive layer to form an oleophilic image.
A method for preparing a lithographic printing plate comprising
- (a) imagewise exposing a photosensitive lithographic printing plate precursor comprising, in sequence, a support having a hydrophilic surface, a non-silver photosensitive layer capable of forming an oleophilic image, and a photographic silver halide emulsion coating,
- wherein said silver halide emulsion coating comprises silver halide grains with an average grain size not exceeding 0.7 micron,
- (b) subjecting said exposed plate to a first development with a developer containing a compound represented by the formula (I)
- R.sup.1 NHNHCOR.sup.2 (I)
- wherein R.sup.1 represents an aryl group, and R.sup.2 represents hydrogen, an aryl group or an aliphatic group, a dihydroxybenzene reducing agent, and free sulfite ions having a concentration of at least 0.18 mol/l.,
- (c) fixing the developed photographic coating,
- (d) uniformly exposing the thus-processed plate to radiation to which said non-silver photosensitive layer is sensitive,
- (e) washing to remove said silver halide emulsion coating, and
- (f) processing the plate with a second developer capable of developing said non-silver photosensitive layer to form an oleophilic image.
Dependencies are inferred from the claim text.