| 摘要 |
PROBLEM TO BE SOLVED: To improve an image reproducibility while keeping an ink mileage favorable by containing at least a compound which can be decomposed when receiving a laser radiation, and a thermo-setting compound in the heat-sensitive layer of a directly drawing type lithographic printing plate original plate wherein the heat-sensitive layer and an ink repelling layer are provided on a base sheet. SOLUTION: A heat-sensitive layer in this direct drawing type lithographic printing plate original plate wherein on a base sheet, the heat-sensitive layer and an ink repelling layer are provided in this order, is formed of a substance containing (a) a compound which can be decomposed by the action of a laser radiation, and (b) a thermo-setting compound. As the compound (a), ammonium nitrate, potassium nitrate, sodium nitrate, a carbonic ester compound or the like can be counted as a compound which does not absorb laser beams by the compound itself, but is decomposed by the action of another compound which absorbs laser beams. Also, as the compound (b), a novolac resin, a resol resin, a phenol-furfural resin or the like can be counted, and as the ink repelling layer, a silicone rubber layer is used. |
