| 摘要 |
PROBLEM TO BE SOLVED: To enhance print dimensions and accuracy while preventing deterioration in workability by forming a plurality of microprotrusions on the surface of a plate cylinder while specifying the height and the surface average number thereof. SOLUTION: A plurality of microprotrusions are formed, while being distributed, on the surrounding surface of a plate cylinder. More specifically, microprotrusions having height of 40μm or above are formed at a rate of 20 pieces/cm<2> in surface average and microprotrusions having height of 3μm or above are formed at a rate of 25 pieces/cm<2> . Consequently, distortion suppressing force of a lithographic printing plate acts effectively at the time of printing. The microprotrusion has rod-like, pyramidal or acicular shape. The microprotrusions are formed on the plate surface by (1) direct blasting, (2) pressing with a roll having microprotrusions, (3) spraying, (4) electrical discharge machining, (5) laser etching, (6) electron beam abrasion, (7) direct coating with dispersion liquid of microparicles, or the like. The microprotrusions are preferably made of an inorganic material in view point of mechanical strength. |
