| 摘要 |
Provided is a lithographic printing original plate which is characterized by being obtained by forming, on a supporting body, an image recording layer that contains (A) an infrared absorbent, (B) a sulfonium salt, (C) a polymerizable compound and (D) a binder polymer. This lithographic printing original plate is also characterized in that: the sulfonium salt (B) has a triarylsulfonium structure that has three or more electron-withdrawing groups as substituents; and at least one aryl group constituting the triarylsulfonium structure comprises at least one of the electron-withdrawing groups and at least one group that is selected from the group consisting of hydrocarbon groups having 4-12 carbon atoms, groups wherein a hydrocarbon group having 4-12 carbon atoms is bonded with an oxygen atom or a sulfur atom, and ethylene oxide groups having 1-3 repeating units. Consequently, this lithographic printing original plate enables direct recording from digital data of a computer or the like, has high sensitivity, and is capable of forming a high-quality image by suppressing the progression of an undesired curing reaction in a non-image portion. This lithographic printing original plate is capable of providing a lithographic printing plate that has high printing durability. Also provided is a plate making method which uses this lithographic printing original plate. |
