| 摘要 |
PROBLEM TO BE SOLVED: To obtain a lithographic printing plate little in residual color in a nonpicture part, hardly causing contamination and good in erasing property when the plate is exposed to light and developed by forming a layer containing a polymer having acid groups and onium groups on an anodized aluminum substrate. SOLUTION: A layer containing a polymer is formed on an anodized aluminum substrate, and further a positive photosensitive layer is formed thereon. The polymer has a structural component having acid groups, and a structural component having onium groups. By forming the intermediate layer which contains a polymer compd. produced by polymn. of the structural component having acid groups and the structural component having onium groups, the onium groups of the polymer compd. can prevent a dye in the photosensitive layer from adsorbing to the substrate. In a nonpicture part, the acid groups in the polymer compd. easily dissociate with an alkali developer, so that the polymer compd. is dissolved and removed form the substrate. Thus, the obtd. plate has excellent color remaining property, hardly causes contamination and has improved erasing property. |
