| 摘要 |
PROBLEM TO BE SOLVED: To provide an original plate for lithographic printing which certainly prevents dilatation of a printing plate of a lithographic printing plate or its positional deviation on a plate cylinder of a printer, and is applicable to multi- color and multi-sheet printing modes, and also ensure satisfactory printing performance and printing durability under severe use conditions, and further, the easy attachment/detachment of a plate material even when an automatic plate supply printing system is adopted. SOLUTION: In a method for printing with a block copy sheet interposed between the plate cylinder and a lithographic printing plate with the back made of a material other than a metal, the back of the lithographic printing plate is constituted of a material showing a Rockwell hardness of M60 or more at 20 deg.C with the other characteristics that a centerline average roughness (Ra) of the material is 0.5μm or more and the Rockwell hardness of a material constituting the face of the block copy sheet on the side in contact with the back of the lithographic printing plate, is lower than the Rockwell hardness of the back material of the lithographic printing plate.
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