Patent ID: 8012668

Claim:
A planographic printing plate precursor comprising: a support; a hydrophilic layer comprising a hydrophilic polymer chemically bonded to a surface of the support, where the hydrophilic polymer has a positively-charged substituent and at least one reactive group selected from the group consisting of a reactive group capable of directly chemically bonding to a surface of the support and a reactive group capable of chemically bonding to a surface of the support via a crosslinked structure; and an image forming layer, wherein the hydrophilic layer and the image forming layer are provided in that order on the support, wherein the hydrophilic polymer includes a structural unit (i) and a structural unit (ii) of the following Formula (1): wherein Formula (1) represents a polymer having a silane coupling group represented by the structural unit (i) on an end of a polymer unit represented by the structural unit (ii); wherein in Formula (1): R 1 , R 2 , R 3 , and R 4 each independently represents a hydrogen atom or a substituent having 1 to 30 carbon atoms; m represents 0, 1, or 2; L 1 and L 2 each independently represents a single bond or an organic linking group; and Y 1 represents an ammonio group, a substituted ammonio group, a phosphonio group, or a substituted phosphonio group; and wherein the counter anion of the positively-charged substituent is SO 4 2− , S 2 O 3 2− , SO 3 − , a halogen ion, ClO 4 − , BF 4 − , PF 6 − , SbF 6 − , BiCl 5 − , AsF 6 − , SbCl 6 − , SnCl 6 − , R—SO 3 − , or R—COO − , wherein R is a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group.