Patent ID: 7273691

Claim:
A planographic printing plate precursor comprising a substrate having disposed thereon a hydrophilic layer which includes hydrophilic graft chains and a crosslinked structure formed through hydrolytic polycondensation of an alkoxide of an element selected from Si, Ti, Zr and Al, wherein the hydrophilic layer includes a polymer compound represented by the following general formula (I): general formula (I) wherein each of R 1 , R 2 , R 3 and R 4 independently represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms; m is an integer of 0 to 2; n is an integer of 1 to 8; L represents a single bond or an organic linking group; Y represents —NHCOR 5 , —CONH 2 , —CON(R 5 ) 2 , —COR 5 ,—OH, —CO 2 M or —SO 3 M; R 5 represents an alkyl group having 1 to 8 carbon atoms; and M represents one of a hydrogen atom, an alkali metal, an alkaline earth metal and an onium and wherein the planographic printing plate precursor further comprises an image forming layer on the hydrophilic layer, and the image forming layer contains a polymer compound including a functional group that changes from one of hydrophilic to hydrophobic and hydrophobic to hydrophilic in the presence of an acid, by application of heat, or by irradiation with radiation.