Patent ID: 7998659
Filing Date: 2011-08-16
Classification: G03F

Abstract:
1. In a process for producing letterpress printing plate comprising irradiating a pattern light with a chemical ray to a photosensitive resin layer for the original printing plate in which a photosensitive resin layer is at least formed on a support, and then obtaining the printing plate for letterpress printing by developing with a developing solution consisting of water to form a resin layer having a relief pattern on the support for printing, the process comprising steps of: irradiating a non-ultraviolet ray on a mask material layer of a photosensitive laminated original printing plate for letterpress printing to allow the irradiated part of the mask material layer to sublimate by the irradiation, thereby changing into a mask image layer which corresponds to an ultraviolet transmissive region; irradiating an ultraviolet ray on the photosensitive resin layer with the mask image layer as a mask; and removing with a developing solution both the mask material layer remaining without irradiation of the non-ultraviolet ray and the ultraviolet ray unirradiated region of the photosensitive resin layer in the uncured state, wherein the non-ultraviolet ray absorbent organic coloring matter in the mask material layer absorbs the non-ultraviolet ray, whereby the mask material layer sublimates and disappears due to the absorbed energy, and wherein the developing solution can be prevented from contamination due to the absence of generation of developing sludge.