| 摘要 |
PURPOSE:To improve developing property and to easily reproduce even fine dots by using a specified amt. of specified ether carboxylic acid as a developer. CONSTITUTION:A photosetting layer and a silicone rubber layer are formed on a substrate, and the silicone rubber layer is used as an ink-repelling layer. The developer for this planographic printing plate contains >=0.5wt.% ether carboxylic acid expressed by formula. In formula, R is an alkyl group of 1-20 carbon number, m is 1-10, and n is 1-10. By lightly rubbing the printing plate with this developer with a soft pad such as gauze or nonwoven fabric, only the silicone rubber layer in a picture line area is substantially peeled to expose the photosetting layer in the picture line area. Thereby, the obtd. printing plate shows good reproducibility of even fine dots in a short developing time and has little scratch or defect. |
