| 摘要 |
PROBLEM TO BE SOLVED: To realize offset printing without necessitating damping water only by image exposure without passing through a developing process by providing a layer incorporating polyorganosiloxane in which photocatalyst semiconductor particles made hydrophilic by exposure are dispersed on a supporting body. SOLUTION: This planographic printing plate is constituted by providing at least the layer incorporating the polyorganosiloxane in which the photocatalyst semiconductor particles made hydrophilic by the exposure are dispersed on the supporting body. By performing image-exposure to the plate with a light beam capable of exciting the photocatalyst semiconductor particles, an unexposure part has ink repulsive property and an exposure part has amphipathic property to realize ink sticking property, so that the offset printing is performed without performing development by utilizing that ink receptive property can be changed. It is desirable to use titanias(TiO2 ), ZnO, SnO, SrTiO2 , WO3 and Bi2 O3 as the photocatalyst semiconductor particles to be used, especially, anatase type titania is suitably used. |
