| abstract |
A positive working lithographic printing platenprecursor comprising a lower layer containing anwater-insoluble and alkali-soluble resin, and an uppernheat-sensitive layer containing a water-insoluble andnalkali-soluble resin and an infrared absorbing dye andnincreasing the solubility in an alkaline aqueous solution bynheating, provided in this order on a hydrophilic support, andn(a) the upper heat-sensitive layer containing at least twonkinds of surface active agents, or (b) the lower layer andnupper heat-sensitive layer each containing a surface activenagent different from each other. |