| 摘要 |
PROBLEM TO BE SOLVED: To provide an original plate for lithographic printing for making a printing plate which has an image part and a non-image part kept distinguishably defined and prints an ultra-sharp and high quality image with the help of a simple printing plate making method requiring no alkali developing solution, and also the original plate for lithographic printing which solves a defect found in a printing plate making method using a laser exposure, that is, by directly mounting the original plate on a printing press for a printing plate making process without performing a developing treatment after scan exposure in a short time and which makes the printing plate almost free from print smears on the printing face due to fouling by contaminants in the air, even when the printing plate is used for printing after being left alone in the air for a long time following the formation of an image. SOLUTION: The original plate for the lithographic printing having a lipophilic layer formed on the surface of a hydrophilic substrate made up of at least one of metallic oxides with a photocatalytic function is irradiated imagewise with a laser beam. Further, the original plate is exposed to an ultraviolet light as a second stage exposure and thus the lithographic printing plate is obtained. |
