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

Abstract

A lithographic printing plate precursor including an image recording layer containing an infrared absorber represented by Formula I, on a support, and a method of producing a lithographic printing plate and a lithographic printing method using the lithographic printing plate precursor.

What is claimed is: 
     
         1 . A lithographic printing plate precursor comprising an image recording layer containing an infrared absorber represented by Formula I, on a support: 
       
         
           
           
               
               
           
         
       
       in Formula I, 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, a naphthalene ring, 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 5  and R 6  independently represents a hydrocarbon group which optionally forms a 5-membered ring or a 6-membered ring, 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 the infrared absorber represented by Formula I is an infrared absorber represented by Formula II: 
       
         
           
           
               
               
           
         
       
       in Formula II, 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, a naphthalene ring, 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. 
     
     
         3 . The lithographic printing plate precursor according to  claim 1 , wherein the image recording layer further contains a polymerizable compound and a polymerization initiator. 
     
     
         4 . The lithographic printing plate precursor according to  claim 3 , wherein the polymerization initiator is an iodonium-based polymerization initiator. 
     
     
         5 . The lithographic printing plate precursor according to  claim 2 , wherein the image recording layer further contains a polymerizable compound and a polymerization initiator. 
     
     
         6 . The lithographic printing plate precursor according to  claim 5 , wherein the polymerization initiator is an iodonium-based polymerization initiator. 
     
     
         7 . The lithographic printing plate precursor according to  claim 1 , wherein the image recording layer further contains a thermoplastic polymer particle. 
     
     
         8 . The lithographic printing plate precursor according to  claim 7 , wherein the polymer contained in the thermoplastic polymer particle contains any or both monomer units of a monomer unit derived from styrene and a monomer unit derived from an acrylic compound. 
     
     
         9 . The lithographic printing plate precursor according to  claim 7 , wherein the polymer contained in the thermoplastic polymer particle is a styrene-acrylonitrile resin. 
     
     
         10 . The lithographic printing plate precursor according to  claim 7 , wherein the weight average molecular weight of the polymer contained in the thermoplastic polymer particle is from 5,000 to 1,000,000. 
     
     
         11 . The lithographic printing plate precursor according to  claim 7 , wherein the volume average particle size of the thermoplastic polymer particle is from 0.01 μm to 50 μm. 
     
     
         12 . The lithographic printing plate precursor according to  claim 7 , wherein the content of the thermoplastic polymer particle with respect to the total mass of the image recording layer is from 20% by mass to 95% by mass. 
     
     
         13 . The lithographic printing plate precursor according to  claim 2 , wherein the image recording layer further contains a thermoplastic polymer particle. 
     
     
         14 . The lithographic printing plate precursor according to  claim 13 , wherein the polymer contained in the thermoplastic polymer particle contains any or both monomer units of a monomer unit derived from styrene and a monomer unit derived from an acrylic compound. 
     
     
         15 . The lithographic printing plate precursor according to  claim 13 , wherein the polymer contained in the thermoplastic polymer particle is a styrene-acrylonitrile resin. 
     
     
         16 . The lithographic printing plate precursor according to  claim 1 , wherein the image recording layer further contains a leuco compound. 
     
     
         17 . The lithographic printing plate precursor according to  claim 1 , wherein the image recording layer is removable by any or both of dampening water and a printing ink. 
     
     
         18 . The lithographic printing plate precursor according to  claim 1 , wherein the image recording layer is gum-developable. 
     
     
         19 . 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.   
     
     
         20 . A lithographic printing method 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;   an on-press development step of feeding at least one of a printing ink or dampening water to remove the unexposed area; and   a printing step of feeding a printing ink to a lithographic printing plate subjected to on-press development in the on-press development step, to perform printing on a recording medium, in this order.