Lithographic printing plate precursor, method of producing lithographic printing plate, and lithographic printing method

1. A lithographic printing plate precursor comprising an image recording layer containing an infrared absorber represented by Formula II, a polymerizable compound, and a polymerization initiator on a support,

wherein the polymerizable compound contains a deca- or higher polyfunctional ethylenically unsaturated compound and further contains an unsaturated ester of alcohol, wherein the unsaturated ester of alcohol is a tri- or higher polyfunctional ethylenically unsaturated compound:

in Formula Il, each of X 1 and X 2 independently represents a sulfur atom, an oxygen atom, or a dialkylmethylene group having 12 or less carbon atoms, each of Y 1 and Y 2 independently represents a monovalent organic group or a hydrogen atom, each of Z 1 and Z 2 independently represents a benzene ring unsubstituted or substituted with an electron-donating group or an aryl group having from 6 to 20 carbon atoms, a naphthalene ring unsubstituted or substituted with an electron-donating group or an aryl group having from 6 to 20 carbon atoms, or a 6- to 20-membered heteroaromatic ring unsubstituted or substituted with an electron-donating group or an aryl group having from 6 to 20 carbon atoms, each of R 1 , R 2 , R 3 , and R 4 independently represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms, each of R 7 , R 8 , R 9 , and R 10 independently represents a hydrogen atom or a monovalent organic group, and A represents a counter ion present in a case in which charge neutralization is needed.

2. The lithographic printing plate precursor according to claim 1 ,

wherein in Formula II, each of X 1 and X 2 independently represents a dialkylmethylene group having 12 or less carbon atoms, each of Y 1 and Y 2 independently represents an alkyl group having from 1 to 10 carbon atoms, each of Z 1 and Z 2 independently represents an unsubstituted benzene ring, each of R 1 , R 2 , R 3 , and R 4 independently represents a hydrogen atom, and each of R 7 , R 8 , R 9 , and R 10 independently represents a hydrogen atom.

3. The lithographic printing plate precursor according to claim 1 ,

wherein the polymerization initiator is a diphenyliodonium salt substituted with an alkyl group.

4. The lithographic printing plate precursor according to claim 1 , wherein the image recording layer further contains a leuco compound.

5. The lithographic printing plate precursor according to claim 1 , wherein the image recording layer is removable by one or both of dampening water and a printing ink.

6. A method of producing a lithographic printing plate, comprising:

an exposure step of image-wise exposing the lithographic printing plate precursor according to claim 1 , to form an exposed area and an unexposed area; and

an on-press development step of feeding at least one of a printing ink or dampening water to remove the unexposed area.

7. The lithographic printing plate precursor according to claim 1 , wherein the image recording layer further contains a thermoplastic polymer particle, and a polymer contained in the thermoplastic polymer particle contains a monomer unit derived from styrene and a monomer unit derived from an acrylic compound.

8. The lithographic printing plate precursor according to claim 7 ,

wherein in Formula II, each of X 1 and X 2 independently represents a dialkylmethylene group having 12 or less carbon atoms, each of Y 1 and Y 2 independently represents an alkyl group having from 1 to 10 carbon atoms, each of Z 1 and Z 2 independently represents an unsubstituted benzene ring, each of R 1 , R 2 , R 3 , and R 4 independently represents a hydrogen atom, and each of R 7 , R 8 , R 9 , and R 10 independently represents a hydrogen atom.