| 摘要 |
PROBLEM TO BE SOLVED: To obtain a lithographic printing plate which can laser record with a low cost, high sensitivity and easy handling without necessity of developing by providing a porous layer on a support, and impregnating the layer with a surface layer melted by a heating effect of a photothermal conversion layer. SOLUTION: A porous layer 2, a photothermal conversion layer 3 and a surface layer 4 are sequentially provided on a support 1 or the porous layer and the surface layer used also as the photothermal conversion layer are sequentially provided on the support to form the lithographic printing plate. Here, the porous layer is formed by coating the support with a dispersing substance obtained by dispersing granular or powder-like substance in a relatively little binder polymer. As the material of the porous layer, a material having good wettability with a surface layer dissolving liquid is used. A particle size of the substance is preferably in a range of 0.01 to 10 μm. Further, a thickness of the layer 2 is set to a range of 2 to 100 μm, and a void fraction of the layer 2 is set to a range of 10 to 70%. Thus, the lithographic printing plate which can laser record and has high sensitivity and unnecessity of developing can be obtained. |
