| 摘要 |
PROBLEM TO BE SOLVED: To provide a lithographic printing plate directly engraved by an infrared laser to be stably manufactured while maintaining excellent adhesive properties, plate wear resistance, difficulty to stain, hydrophilic property and water retention characteristics by realizing excellent image reproducibility and resolution with high sensitivity. SOLUTION: The lithographic printing plate comprises an anodized film made of 99 wt.% of aluminum having a length of 3 to 60 μm in a direction perpendicular to a rolling direction of surface recrystallized grains, surface roughness Ra of 0.3 to 0.4 m and Sm of 20 to 70 μm, L' (metric lightness) represented by a CIELAB space after anodizing of 40 to 70 and an S content measured by a fluorescent X ray of 1,500 to 1,500,000 cPs on a support, and an infrared laser photosensitive material coating the support in such a manner that a surface Si amount after laser exposure and development of 1 to 25 atm.%. |
