PHOTOSENSITIVE PLANOGRAPHIC PRINTING PLATE

摘要

PROBLEM TO BE SOLVED: To obtain a photosensitive planographic printing plate which is ameliorated in the contamination of the plate in non-printing element parts at the time of development, blanket contamination and the contamination at the time of decreasing of moistening water and is decreased in the sludge and has good plate wear. SOLUTION: This photosensitive planographic printing plate is constituted by providing surface of a base having an anodically oxidized film and having the center line average height (Ra) of the surface of 0.5 to 0.7μm and average roughness (Rz) of 3.0 to 6.0μm with an Si atom-contg. hydrophilic layer of 50 to 120 mg/m<2> in terms of SiO2 and providing the surface of the hydrophilically treated base of 30 to 50 dyn/cm in the hydrogen bondγ(H) of the surface energy expressed by the following general equation (1) on the hydrophilic layer with a photopolymerization sensitive layer. The general equation isγ(H)=[ 1.159+2.159×cos (contact angle: H2 O) - cos (contact angle: CH2 I2 )}/0.379]<2> (dyn/cm). The contact angle is measured 30 seconds after dropping H2 O: 1.7μl, CH2 I2 : 1.3μl.