| 摘要 |
PURPOSE:To obtain a positive-positive plate or negative-positive plate permitting test printing by using a photosensitive layer consisting essentially of an indolinobenzopirylspiran [2, 2'] derivat (expressed hereunder as SP) which is a photochromic compound. CONSTITUTION:A metallic layer 3 of which the affinity to water or oil differs from that of a substrate is provided on a substrate 2, and further a photosensitive layer 4 consisting essentially of SP is provided thereon, whereby an original plate is formed. There is the SP which exhibits positive photochromic (colors 4a when irradiated with UV rays) and the one which exhibits reverse photochromic (discolors 4b when irradiated with visible light). The solubility with solvents differs considerably with the discoloring type and the coloring type. Hence, UV rays or visible rays are irradiated to the original plate to allow the layer 4 to color, and the original plate having such image 4 pattern is immersed in a solvent and is developed, thence the layer 3 is etched with an etching soln. to expose the surface of the substrate 2, whereby the printing plate is obtained. |
