| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an original plate of an on-machine development type lithographic printing plate which can record an image by means of a laser and has excellent plate detectability and resistance to plate wear, and a lithographic printing method. <P>SOLUTION: The original plate of the lithographic printing plate has an image recording layer from which an unexposed part can be removed by supplying a printing ink and damping water on a support. The image recording layer contains (a) an infrared absorbent represented by a formula (1), (b) at least, one polymerization initiator selected from a group composed of a diaryliodonium salt compound and a sulfonium salt compound both of which have different substituting groups, respectively, and (c) a polymerizable compound. In the formula, R<SP>1a</SP>and R<SP>2a</SP>are alkyl groups with oxygen atoms etc., m is an integer of 1 or 2, Y is a dialkylmethylene group etc., Z<SP>1</SP>and Z<SP>2</SP>are aromatic hydrocarbon rings etc., B is an n-value organic group, n is an integer of 2 to 6, and A<SP>-</SP>is a counter anion. <P>COPYRIGHT: (C)2011,JPO&INPIT |
