| 摘要 |
PURPOSE:To enhance the printing resistance, resolving power and sensitivity of a lithographic plate by forming a lipophilic resin layer and a silver salt photosensitive material layer on a hyrophilic substrate in this order, subjecting the latter layer to patternwise exposure and development, and carrying out activated plasma treatment using the resulting silver salt image as a mask to partially disclose the substrate surface. CONSTITUTION:Lipophilic synthetic or natural resin layer 2 and silver salt photosensitive material layer 3 are formed in this order on substrate 1 such as Al plate rendered hydrophilic. Layer 3 is exposed through halftone pattern 4, developed, and fixed to form blackened silver part 31 and gelatin film 33 of unexposed part 32. The layer is then irradiated with activated plasma to remove film 33 and resin 2 under film 33, thereby partially disclosing the surface of substrate 1, and silver part 31 is finally removed to obtain a lithographic plate. The exposed pattern 4 may as well be developed and bleached to form an unexposed emulsion part used as a mask for plasma treatment. This lithographic plate has superior printing resistance and resolving power. |
