Infrared-ray photosensitive planographic printing plate precursor

An infrared-ray photosensitive planographic printing plate precursor, comprising:

• a support,
• a recording layer provided on one side of the support, and
• a back coating layer provided on a side opposite to a side having the recording layer of the support,
• wherein, the recording layer contains (a) a long chain alkyl group-containing polymer containing a vinyl monomer having a carboxyl group at a composition ratio within a range from 20 to 99 mol %, and (b) an infrared absorbing agent, and can form an image by infrared-ray irradiation, and
• the back coating layer is a back coating layer (A) containing at least one kind of resin selected from the group consisting of a saturated polymerized polyester resin, a phenoxy resin, a polyvinyl acetal resin, and a vinylidene chloride copolymer resin.

An infrared-ray photosensitive planographic printing plate precursor, comprising:

• a support,
• a recording layer provided on one side of the support, and
• a back coating layer provided on a side opposite to a side having the recording layer of the support,
• wherein the recording layer contains (a) a long chain alkyl group-containing polymer containing a vinyl monomer having a carboxyl group at a composition ratio within a range from 20 to 99 mol %, and (b) an infrared absorbing agent, and can form an image by infrared-ray irradiation, and
• the back coating layer is a back coating layer (B) containing the following (i) to (iii):
• (i) a metal oxide obtained by hydrolyzing and polycondensing an organic metal compound or an inorganic metal compound,
• (ii) a colloidal silica sol, and
• (iii) an organic polymer compound.