| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide such a thermosensitive lithographic original plate for direct plate making by using IR laser, that is capable of recording with high sensitivity and excellent in scratch resistance. <P>SOLUTION: The original plate has a recording layer on a hydrophilic supporting body. The recording layer consists of a lower layer containing a water-insoluble and alkali-soluble resin and an upper layer containing a water-insoluble and alkali-soluble resin, a development suppressing agent and a dye which develops a color by changes in pH, has a lactone skeleton, sulfolactone skeleton or spiropyran skeleton in the molecule and increases its solubility with an alkaline aqueous solution by exposure. The original plate is characterized in that at least either the lower layer or the upper layer of the recording layer contains an IR absorbent. Preferably, the lower layer contains at least one kind of water-insoluble and alkali-soluble resin selected from a group comprising acrylic resin, urethane resin and acetal resin. <P>COPYRIGHT: (C)2004,JPO |
