| 摘要 |
PURPOSE:To improve the water-retaining property of the planographic printing plate and to obtain the plate which is less deteriorated in printing resistance by incorporating a specific compd. into its surface layer. CONSTITUTION:The compd. expressed by formula I is incorporated into the planographic printing plate formed by applying at least a silver halide emulsion layer and physical development nucleus layer on a base and incorporating at least one of colloidal silica or alumina sol into the surface layer of the planographic printing plate. In the formula I, (m) and (n) denote the molar number which is necessary for increasing the average mol. wt. of a block polymer to >=200 and is necessary for m/m+n to attain 50 to 100wt.%. Then, the compd. expressed by the formula acts as a swelling agent to the colloidal silica or alumina sol used for the surface layer and does not accelerate the hardening deterioration of a gelatin layer contg. the surface layer any more. The water- retaining property of the planographic printing plate to which a silver complex salt diffusion transfer method is applied is greatly improved in this way and the planographic printing plate which is less deteriorated in printing resistance is obtd. |
