| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an original plate for a lithographic printing for use in CTP, which can be handled in a bright room in such a manner as to be sensitive to light of a near infrared area, which enables an image to be directly formed on the plate by using laser light, which dispenses with development and a wiping operation, which suppresses the occurrence of scumming of a non-image area (unexposed area) and a deterioration caused by printing, which brings about the excellent property of adhesion of ink to an image area (laser exposure area), and which accomplishes crisp high-quality printing. <P>SOLUTION: In the original plate for the lithographic printing, a hydrophilic-resin photosensitive layer with properties, wherein a surface of the exposure area is changed from hydrophilicity to an affinity for the ink by laser exposure, is provided on a substrate; and a ratio of a water-insoluble component of the hydrophilic-resin photosensitive layer is in a range of ≥60 wt% and <96 wt%. Preferably, the hydrophilic-resin photosensitive layer is constituted by crosslinking a water-based photosensitive resin composition which contains a hydrophilic polymer, a crosslinking agent, a hydrophobic polymer, an optical absorbent and a hydrophilic additive. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
