| abstract |
Provided is a method for producing a lithographic printing plate for UV exposure via a lithographic film and for on-machine development using an on-machine development-type lithographic printing plate original capable of image exposure by an infrared laser, wherein plate durability and on-machine development capability are good, gas is not released during on-machine development, and vacuum adhesion with a lithographic film is good. The a method for producing a lithographic printing plate comprises the steps of: (1) preparing a lithographic printing plate original, which is capable of image formation using a semiconductor laser that emits infrared rays having a wavelength of 760 to 1,200 nm and which comprises, in succession, a supporting body and an image recording layer containing a cyanine dye, a diphenyl iodonium salt or triphenyl sulfonium salt in which the phenyl groups are optionally substituted, a radical polymerizable compound, and polymer microparticles having a polyoxyalkylene side chain; (2) placing a lithographic film on the lithographic printing plate original and reducing pressure such that the lithographic film adheres closely to the lithographic printing plate original; (3) performing UV exposure; and (4) performing on-machine development. |