Inkjet-imageable lithographic printing members and methods of preparing and imaging them

Abstract

Lithographic printing plates are imaged using an inkjet printer to imagewise apply a chemical or masking agent onto the plate surface. In some embodiments, the chemical causes an affinity change, thereby facilitating lithographic printing.

1 . A lithographic printing member comprising a hydrophilic layer having an exposed surface, at least the surface of the layer comprising a material that responds to an imaging fluid by undergoing a phase change from a hydrophilic state to an oleophilic state.  
     
     
         2 . The printing member of  claim 1 , wherein the top layer comprises a crosslinked hydrophilic polymer.  
     
     
         3 . The printing member of  claim 2 , wherein the hydrophilic polymer is selected from the group consisting of polyvinyl phosphonic acid, polyvinyl alcohol comprising an amine moiety, and any polymer comprising at least one of a carboxylic acid moiety, a sulfonic acid moiety, and a phosphonic acid moiety.  
     
     
         4 . The printing member of  claim 1 , wherein the imaging fluid comprises an esterifying agent.  
     
     
         5 . The printing member of  claim 4 , wherein the esterifying agent is selected from the group consisting of tetramethylammonium hydroxide, phenyltrimethylammonium hydroxide, trimethylsulfonium hydroxide, trimethylsulfoxonium hydroxide, and 1,3-(bistripropylammonium) xylene hydroxide.  
     
     
         6 . The printing member of  claim 1 , wherein the imaging fluid comprises an alkylating agent.  
     
     
         7 . The printing member of  claim 1 , wherein the imaging fluid comprises a quaternary ammonium salt.  
     
     
         8 . The printing member of  claim 1 , further comprising a hydrophilic substrate beneath the hydrophilic layer.  
     
     
         9 . A system for lithographic printing comprising: 
 (a) a printing member comprising a hydrophilic layer having an exposed surface, and    (b) an imaging fluid;    wherein at least the surface of the layer comprises a material that responds to the imaging fluid by undergoing a phase change from a hydrophilic state to an oleophilic state.    
     
     
         10 . The system of  claim 9 , wherein the top layer comprises a crosslinked hydrophilic polymer.  
     
     
         11 . The system of  claim 10 , wherein the hydrophilic polymer is selected from the group consisting of polyvinyl phosphonic acid, polyvinyl alcohol comprising an amine moiety, and any polymer comprising at least one of a carboxylic acid moiety, a sulfonic acid moiety, and a phosphonic acid moiety.  
     
     
         12 . The system of  claim 9 , wherein the imaging fluid comprises an esterifying agent.  
     
     
         13 . The system of  claim 12 , wherein the esterifying agent is selected from the group consisting of tetramethylammonium hydroxide, phenyltrimethylammonium hydroxide, trimethylsulfonium hydroxide, trimethylsulfoxonium hydroxide, and 1,3-(bistripropylammonium) xylene hydroxide.  
     
     
         14 . The system of  claim 9 , wherein the imaging fluid comprises an alkylating agent.  
     
     
         15 . The system of  claim 9 , wherein the imaging fluid comprises a polymer comprising a quaternary ammonium salt.  
     
     
         16 . The system of  claim 9 , wherein the printing member further comprises a hydrophilic substrate beneath the hydrophilic layer.  
     
     
         17 . A method of imaging a lithographic printing member, the method comprising the steps of: 
 (a) providing a printing member comprising a hydrophilic layer having an exposed surface, at least the surface of the layer undergoing a phase change from a hydrophilic state to an oleophilic state in response to an imaging fluid; and    (b) dispensing the imaging fluid in an imagewise pattern, the imaging fluid chemically reacting with at least the surface of the layer and inducing the    phase change, thereby creating an imagewise lithographic pattern on the printing member.    
     
     
         18 . The method of  claim 17 , wherein the top layer comprises a crosslinked hydrophilic polymer.  
     
     
         19 . The method of  claim 18 , wherein the hydrophilic polymer is selected from the group consisting of polyvinyl phosphonic acid, polyvinyl alcohol comprising an amine moiety, and any polymer comprising at least one of a carboxylic acid moiety, a sulfonic acid moiety, and a phosphonic acid moiety.  
     
     
         20 . The method of  claim 17 , wherein the imaging fluid comprises an esterifying agent.  
     
     
         21 . The method of  claim 20 , wherein the esterifying agent is selected from the group consisting of tetramethylammonium hydroxide, phenyltrimethylammonium hydroxide, trimethylsulfonium hydroxide, trimethylsulfoxonium hydroxide, and 1,3-(bistripropylammonium) xylene hydroxide.  
     
     
         22 . The method of  claim 17 , wherein the imaging fluid comprises an alkylating agent.  
     
     
         23 . The method of  claim 17 , wherein the imaging fluid comprises a quaternary ammonium salt.  
     
     
         24 . The method of  claim 17 , wherein the printing member further comprises a hydrophilic substrate beneath the hydrophilic layer.