Planographic printing plate precursor

摘要

A planographic printing plate formed of a support having sequentially disposed thereon a first layer, that is structured by a heat-insulating material having a low thermal conductivity, and that is made hydrophilic by being processed with one of an alkali and a silicate in an alkali developing solution after exposure; and a second layer whose alkali developability is changed, without ablation, by being irradiated with an infrared ray. Alternatively, a support that is structured by a heat-insulating material whose thermal conductivity is low, and in which a surface thereof is made hydrophilic by being processed with one of an alkali and a silicate in an alkali developing solution after exposure, may also be used as the support.