Patent ID: 7258961
Filing Date: 2007-08-21
Classification: B41C,C09B

Abstract:
1. A positive planographic printing plate precursor comprising a support having successively disposed thereon a lower thermosensitive layer containing a water-insoluble but alkali-soluble polymer compound, and an upper thermosensitive layer containing a water-insoluble but alkali-soluble polymer compound, with solubility in an aqueous alkali solution increasing under heat, wherein both the upper thermosensitive layer and the lower thermosensitive layer contain an IR absorbing dye, wherein the ratio of the IR absorbing dye concentration in the upper thermosensitive layer to the IR absorbing dye concentration in the lower thermosensitive layer is 1.6 to 10.0, and the coating amount of the upper thermosensitive layer is at most 0.4 g/m