Lithographic plates made by spark discharges
First Claim
1. A lithographic plate that is press ready after imaging for printing without dampening comprising a relatively strong, stable substrate, a surface layer composed of an oleophobic polymeric material overlying and supported by said substrate, a multiplicity of electrically conductive particles dispersed in said surface layer and an oleophilic surface under said surface layer, said surface layer being decomposable to expose said oleophilic surface by spark discharges from a non-contacting electrode scanned across said surface layer.
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Accused Products
Abstract
A lithographic plate for printing without dampening comprising a strong stable substrate, an oleophobic surface layer on the substrate and an oleophilic surface underlying the surface layer, the surface layer being decomposable by spark discharges originating from a non-contacting electrode scanned across the plate surface. A preferred plate embodiment includes a multiplicity of tiny electrically conductive peaks in the plate which point away from the substrate and are in a relatively uniform distribution across the plate surface area.
44 Citations
46 Claims
- 1. A lithographic plate that is press ready after imaging for printing without dampening comprising a relatively strong, stable substrate, a surface layer composed of an oleophobic polymeric material overlying and supported by said substrate, a multiplicity of electrically conductive particles dispersed in said surface layer and an oleophilic surface under said surface layer, said surface layer being decomposable to expose said oleophilic surface by spark discharges from a non-contacting electrode scanned across said surface layer.
- 7. A lithographic plate that is press ready after imaging for printing without dampening comprising a relatively strong stable substrate, an organic plastic oleophobic surface layer overlying and supported by said substrate, an oleophilic surface under said surface layer and providing means for providing a multiplicity of tiny electrically conductive peaks in said plate, said peaks pointing away from said substrate and being in a relatively uniform distribution across the plate surface area, said surface layer being decomposible to expose said oleophilic surface by spark discharge from a non-contacting electrode.
- 38. A lithographic plate that is transformable so as to change the affinity of said plate for ink, said plate being a layered structure including a relatively strong stable substrate and an organic plastic oleophobic surface layer overlying and supported by said substrate, and means for providing a multiplicity of tiny electrically conductive peaks in said plate, said peaks pointing away from said substrate and being in a relatively uniform distribution across the plate surface area, said providing means including a thin electrically conductive layer under said surface layer, an organic plastic underlayer between said conductive layer and said substrate and a multiplicity of particles dispersed in said underlayer.
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45. A lithographic plate that is transformable so as to change the affinity of said plate for ink, said plate being a layered structure including a relatively strong stable substrate and an organic plastic oleophobic surface layer overlying and supported by said substrate, and means for providing a multiplicity of tiny electrically conductive peaks in said plate, said peaks pointing away from said substrate and being in a relatively uniform distribution across the plate surface area, the portions of said surface layer at said peaks being thinner than the remainder of said surface layer.
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46. A lithographic plate that is transformable so as to change the affinity of said plate for ink, said plate being a layered structure including a relatively strong stable substrate and an organic plastic oleophobic surface layer overlying and supported by said substrate, and means for providing a multiplicity of tiny electrically conductive peaks in said plate, said peaks pointing away from said substrate and being in a relatively uniform distribution across the plate surface area, the portions of said surface layer opposite said peaks being raised above the remainder of said surface layer.
Specification