PRODUCTION OF LITHOGRAPHIC PRINTING PLATE

摘要

PROBLEM TO BE SOLVED: To provide a producing method of a lithographic printing plate which enables laser recording and which satisfies requirements for the removing performance of an ink-repelling layer in the exposed region to laser light and for the printing performance. SOLUTION: The producing method of a lithographic printing plate features that the following processes are sequentially carried out. They are a process to expose a lithographic printing original plate 11 having a photothermal conversion layer and an ink-repelling layer laminated in this order on a support to laser light, a process to rub the surface of the ink-repelling layer with a rubbing member 1a disposed in a developing means 13 without the presence of a liquid, a process to rub the surface of the ink-repelling layer with a rubbing member 1b disposed in a cleaning means 14 in the presence of a detergent liquid containing a surfactant.