Lithographic printing plate precursor and method for producing lithographic printing plate

1. A lithographic printing plate precursor comprising:

an image-recording layer on a hydrophilic support,

wherein the image-recording layer contains an infrared absorbing dye that decomposes by exposure to an infrared ray and a color developer that develops color due to the exposure to an infrared ray,

the infrared absorbing dye is a cyanine dye, and

the cyanine dye is a cyanine dye represented by the following Formula 2,

wherein, in the Formula 2, R 1 represents a group in which an R 1 -L bond is cleaved by exposure to an infrared ray, R 2 and R 3 each independently represent a hydrogen atom or an alkyl group or R 2 and R 3 may be linked to each other to form a ring, Ar 1 and Ar 1 each independently represent a group forming a benzene ring or a naphthalene ring, Y 1 and Y 2 each independently represent an oxygen atom, a sulfur atom, —NR 0 —, or a dialkyl methylene group, R 0 represents a hydrogen atom, an alkyl group, or an aryl group, R 4 and R 5 each independently represent an alkyl group, a —CON group, or a —PO 3 M 2 group, M represents a hydrogen atom, a Na atom, a K atom, or an onium group, R 6 to R 9 each independently represent a hydrogen atom or an alkyl group, L represents (a) a sulfur atom, and R 1 is a group represented by the following Formula (2-1), or (b) —NR 10 —, R 10 represents a hydrogen atom, an alkyl group, or an aryl group, and R 1 that bonds to N is a group represented by the following Formula (3-1), and Za represents a counter ion that neutralizes a charge,

wherein, in the Formula (2-1), ● represents a bonding site with the sulfur atom represented by L in the Formula 2, R 21 's each independently represent a hydrogen atom, an alkyl group, or an aryl group, and R 22 represents an aryl group, an alkenyl group, an alkoxy group, or an onium group,

wherein, in the Formula (3-1), ● represents a bonding site with a nitrogen atom included in L in the Formula 2, X 1 and X 2 each independently represent an oxygen atom or a sulfur atom, and Y represents a group represented by the Formula (2-1).

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

wherein, in the Formula 2, R 4 and R 5 each are independently a substituted alkyl group.

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

wherein, in the Formula 2, R 4 and R 5 each are independently an unsubstituted alkyl group.

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

wherein the color developer is a heat color developer.

5. The lithographic printing plate precursor according to claim 4 ,

wherein the heat color developer is at least one compound selected from a spiropyran compound, a spirooxazine compound, a spirolactone compound, and a spirolactam compound.

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

wherein the color developer is an acid color developer, and the image-recording layer further contains an acid-generating agent.

7. The lithographic printing plate precursor according to claim 6 ,

wherein the acid color developer is at least one compound selected from a spiropyran compound, a spirooxazine compound, a spirolactone compound, and a spirolactam compound.

8. The lithographic printing plate precursor according to claim 6 ,

wherein the acid color developer is a spirolactone compound represented by the following Formula 3:

wherein, in the Formula 3, X represents an oxygen atom, a sulfur atom, or —NR 19 —, R 19 represents a hydrogen atom, an alkyl group, or an aryl group, and R's each independently represent a hydrogen atom or a monovalent substituent.

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

wherein, in the Formula 3, X is an oxygen atom.

10. The lithographic printing plate precursor according to claim 6 ,

wherein the acid-generating agent is an electron-donating acid-generating agent.

11. The lithographic printing plate precursor according to claim 6 ,

wherein the acid-generating agent is an electron-accepting acid-generating agent.

12. The lithographic printing plate precursor according to claim 6 ,

wherein the acid-generating agent comprises an electron-donating acid-generating agent and an electron-accepting acid-generating agent.

13. The lithographic printing plate precursor according to claim 10 ,

wherein the electron-donating acid-generating agent is a borate compound.

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

wherein the image-recording layer further contains a polymerizable compound.

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

wherein the image-recording layer further contains a polymer particle.

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

wherein the image-recording layer further contains a binder polymer.

17. A method for producing a lithographic printing plate comprising:

image-exposing the lithographic printing plate precursor according to claim 1 using an infrared laser; and

removing a non-exposed portion of the image-recording layer using at least one selected from printing ink and dampening water on a printer.