| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a positive original plate of a planographic printing plate for an infrared laser for direct plate making excellent in scratch resistance and in discrimination of a formed image. <P>SOLUTION: The original plate of a planographic printing plate is obtained by disposing on a support two or more positive recording layers containing a resin and an infrared absorbing agent and having solubility in an alkaline aqueous solution increased by infrared laser exposure, wherein among the two or more positive recording layers, the positive recording layer closest to the support has a ratio of the dissolution rate in the alkaline aqueous solution between depth and lateral directions being at least <1. In order to attain such a ratio of the dissolution rate, the lower layer preferably has a dispersed phase or high-temperature drying is preferably carried out at the time of forming the lower layer. <P>COPYRIGHT: (C)2007,JPO&INPIT |
