| 摘要 |
PROBLEM TO BE SOLVED: To provide a positive type planographic printing plate material for an IR laser having high sensitivity, excellent in power to discriminate between image and non-image areas, thereby causing little printing stain and excellent also in printing resistance. SOLUTION: The positive type planographic printing plate material has a photosensitive layer containing an alkali-soluble high molecular compound, a material which absorbs light and generates heat and a 5- or 6-membered cyclic lactone compound having a specified structure substituted by an electron withdrawing group on a support. |
