Patent ID: 8148042

Claim:
A heat-sensitive lithographic printing plate precursor comprising: a support having a hydrophilic surface or which is provided with a hydrophilic layer; and on the support, a coating which includes a photopolymerizable composition and an IR dye having a structure according to Formula I: wherein + Y 1 ═ is represented by one of the following structures: Y 2 — is represented by one of the following structures: n is 0, 1, 2, or 3; each of p and q is 0, 1, or 2; R 1 and R 2 are independently an optionally substituted hydrocarbon group, or wherein two of the R 1 , R 2 , R d , or R a groups together include the necessary atoms to form a cyclic structure; at least one of the R d groups is a group which is transformed by a chemical reaction, induced by exposure to IR-radiation or heat, into a group which is a stronger electron-donor than the R d ; or at least one of the R a groups is a group which is transformed by a chemical reaction, induced by exposure to IR-radiation or heat, into a group which is a stronger electron-acceptor than the R a ; the other R d and R a groups are independently represented by a group selected from the list consisting of a hydrogen atom, a halogen atom, —R e , —OR f , —SR g , and —NR u R v ; wherein R e , R f , R g , R u , and R v independently are an optionally substituted aliphatic hydrocarbon group or an optionally substituted (hetero)aryl group; and the transformation provides an increase of the integrated light absorption of the dye between 400 nm and 700 nm.