Patent ID: 7833689

Claim:
A lithographic printing plate precursor comprising a support and an image-recording layer containing at least one infrared absorbing agent of a cyanine dye in which a HOMO energy level of each of substituents present on both terminal nitrogen atoms is −9.0 eV or higher, wherein the infrared absorbing agent is represented by the following formula (II): wherein Y 1 and Y 2 each independently represents an organic connecting group which has 1 or more atoms, contains a carbon atom and may have a substituent, or a single bond; Z 1 and Z 2 each independently represents an aromatic ring which may have a substituent or a hetero aromatic ring which may have a substituent; R 1 and R 2 each independently represents an organic functional group which meets a requirement that a HOMO energy level of R n —Y n —H, in which n is 1 or 2, is −9.0 eV or more; and A − represents a counter ion which exists in case of being necessary for neutralizing a charge; wherein the image-recording layer further contains a polymerization initiator selected from the group consisting of an oxime ester, a diazonium salt, an iodonium salt, and a sulfonium salt, a polymerizable compound and a binder polymer.