| 摘要 |
PROBLEM TO BE SOLVED: To improve the flatness and productivity of a lithographic printing plate by using the printing plate in which the average curvature in the rolling direction, curvature distribution in the breadth direction, and the curvature in the direction perpendicular to the rolling direction are specified respectively. SOLUTION: In a lithographic printing plate 1 in which aluminum, etc., are made a support, the lithographic printing plate 1 in which average curvature in the rolling direction is not greater than 1.5×10<-3> mm<-1> , curvature distribution in the breadth direction is not greater than 1.5×10<-3> mm<-1> , curvature in the direction perpendicular to the rolling direction is not greater than 1.0×10<-3> mm<-1> is used. As regards the printing plate 1, a printing plate in which average surface roughness is 0.3-0.8μm and the difference between the average surface roughness in the rolling direction and that in the direction perpendicular to the rolling direction is not greater than 30% of the average surface roughness is used. The printing plate 1 is manufactured by a process in which an aluminum plate is worked to make its surface rough, subjected to anodic oxidation membrane treatment, coated with a photosensitive layer, and corrected by using a correction roll 20-80mm in diameter and 50-95 degree in rubber hardness.
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