Patent ID: 7288365

Claim:
An image forming method comprising the steps of: (a) conducting a development treatment of exposing a hydrophilic surface of an aluminum support by removing a thermosensitive image formation layer provided on the hydrophilic surface, that is not imagewise heated on a printing press to produce a planographic printing plate, after imagewise heating a planographic printing plate material having the thermosensitive image formation layer provided on the hydrophilic surface of the aluminum support; (b) applying ink to the planographic printing plate to conduct printing employing the inked planographic printing plate; and (c) treating the planographic printing plate with an ink cleaning agent after printing to remove the ink; wherein the hydrophilic surface is colored by a colorant having a solubility of 5-100 g, based on 1 liter of n-decane, and not only the ink is removed, but also the colorant on the hydrophilic surface exposed via removal of the thermosensitive image formation layer is further removed at the same time in step (c).