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

1. A lithographic printing plate precursor comprising:

a hydrophilized aluminum support; and

a water-soluble or water-dispersible negative type image recording layer on the aluminum support,

an arithmetic average height Sa of a surface of an outermost layer on a side opposite to a side where the image recording layer is provided being in a range of from 0.3 μm to 20 μm, and

the image recording layer comprising an infrared absorbing agent and a thermoplastic polymer particle.

2. The lithographic printing plate precursor according to claim 1 , wherein a glass transition temperature (Tg) of the thermoplastic polymer particles is in a range of from 70° C. to 140° C.

3. The lithographic printing plate precursor according to claim 1 , wherein the thermoplastic polymer particle comprises a copolymer formed by copolymerizing at least styrene and acrylonitrile.

4. The lithographic printing plate precursor according to claim 1 , wherein the image recording layer further comprises a hydrophilic resin.

5. The lithographic printing plate precursor according to claim 1 , wherein the infrared absorbing agent has a water-soluble group.

6. The lithographic printing plate precursor according to claim 1 , wherein the image recording layer further comprises a surfactant having a polyoxyalkylene group or a hydroxy group.

7. The lithographic printing plate precursor according to claim 1 , wherein a Bekk smoothness of a surface of the outermost layer on a side opposite to a side where the image recording layer is provided is 1000 seconds or less.

8. The lithographic printing plate precursor according to claim 1 , wherein the outermost layer on a side opposite to a side where the image recording layer is provided is a resin layer which contains at least one kind of particles having an average particle diameter of 0.5 μm to 20 μm.

9. The lithographic printing plate precursor according to claim 1 , wherein a density of the particles is in a range of 500 pcs/m 2 to 500000 pcs/m 2 .

10. The lithographic printing plate precursor according to claim 1 , wherein:

the aluminum support comprises an aluminum plate and an aluminum anodized film disposed on the aluminum plate;

the anodized film is positioned closer to the image recording layer than to the aluminum plate;

the anodized film has micropores extending in a depth direction from the surface of the image recording layer side; and

the average diameter of the micropores in the surface of the anodized film is in a range of from 7 nm to 150 nm.

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

wherein the micropores are formed of large-diameter pores extending to a position at a depth of 10 nm to 1000 nm from the surface of the anodized film and small-diameter pores communicating with a bottom of the large-diameter pores and extending to a position at a depth of 20 nm to 2000 nm from a communication position,

the average diameter of the large-diameter pores in the surface of the anodized film is in a range of 15 nm to 150 nm, and

the average diameter of the small-diameter pores in the communication position is 13 nm or less.

12. A lithographic printing method, comprising:

image-exposing the lithographic printing plate precursor according to claim 1 ;

supplying at least any of printing ink or dampening water and removing an unexposed portion of the image recording layer on a printing press to prepare a lithographic printing plate; and

performing printing using the obtained lithographic printing plate.

13. A lithographic printing method, comprising:

image-exposing the lithographic printing plate precursor according to claim 1 ;

supplying a developer having a pH of 2 to 14 and removing an unexposed portion to prepare a lithographic printing plate; and

performing printing using the obtained lithographic printing plate.