| 摘要 |
PURPOSE:To make it possible to prepare a porous printing plate without use of a die and deal with requirements of different type/small lot production in a very few number of process steps compared to a conventional manufacturing method by allowing a photosensitive layer containing a photosensitive material and a foaming material to be borne on the surface of a porous support. CONSTITUTION:A photosensitive layer 5 containing a photosensitive material 3 (e.g. photopolymerization-type resin) and a foaming material (e.g. dinirosopentamethylene tetramine) is allowed to be borne on the surface of a porous support 2. A light- permeable source document 6 is stacked on thin photosensitive printing medium 1 and both are exposed to a lamp. Then the light of the lamp permeates the transparent part of the source document 6 so that the photosensitive layer 5 on the printing medium 1 becomes exposted to the light. The hardness of the material 3 is increased by photocuring reaction in the photosensitive layer 5 of the exposed part, and at the same time, the material 4 discharges gas, resulting in a transformation to a foam part having a capillary structure. On the other hand, such a transformation does not take place in the photosensitive layer 5 of the part corresponding to the opaque part of the source document. That is, only the printed part becomes a foam as a printing plate. |
