Method and apparatus for producing a photopolymerizing lithographic plate

Abstract

Decrease in sensitivity can be avoided to obtain a stable and highly sensitized photosensitive layer in a process for preparing a photopolymerizing lithographic plate including a coating step and using rubber rollers before and after the coating site. This is achieved by excluding an antioxidant and/or aging retardant from at least the surface of rubber rollers placed before and after the coating site. The photopolymerizing lithographic plate excellent in its sensitivity as compared with the conventional one can be obtained.

What is claimed is:  
     
         1 . A process for preparing a photopolymerizing lithographic plate comprising coating and conveying a web using rubber rollers before and after the coating step, 
 wherein a surface of said rubber rollers to be used at least just before and after said coating step does not substantially contain an antioxidant and/or aging retardant, such that transfer of the antioxidant and/or aging retardant to a photosensitive layer laminated on a substrate on said web is substantially eliminated upon using said rubber rollers for a prolonged period of time or at high temperatures.    
     
     
         2 . The process as defined in  claim 1 , wherein said rubber roller is a roller whose surface is coated with rubber.  
     
     
         3 . The process as defined in  claim 1 , wherein said substrate is an aluminum substrate.  
     
     
         4 . The process as defined in  claim 1 , wherein the rubber constituting at least the surface of said rubber rollers is selected from at least one of ethylene-propylene rubber and urethane rubber.  
     
     
         5 . The process as defined in  claim 1 , wherein said antioxidant is at least one compound selected from phenol, amine and phosphorous series of antioxidants.  
     
     
         6 . The process as defined in  claim 1 , wherein a surface of a back up rubber roller at the coating step does not substantially contain the antioxidant and/or aging retardant.  
     
     
         7 . The process as defined in  claim 1 , wherein one or more rubber rollers disposed upstream of said rubber roller just before said coating step do not-substantially contain the antioxidant and/or aging retardant.  
     
     
         8 . The process as defined in  claim 1 , wherein one or more rubber rollers disposed downstream of said rubber roller just after said coating step do not substantially contain the antioxidant nd/or aging retardant.  
     
     
         9 . The process as defined in  claim 1 , wherein said one or more rubber rollers comprise those contacting a coating surface of said substrate.  
     
     
         10 . The process as defined in  claim 1 , wherein said web is a substrate.  
     
     
         11 . A photopolymerizing lithographic plate which is a product obtained by the process as defined in  claim 1 .  
     
     
         12 . An apparatus for preparing a photopolymerizing lithographic plate comprising a coating site and rubber rollers for conveying a web before and after the coating site, 
 wherein a surface of said rubber rollers to be used at least just before and after said coating step does not substantially contain an antioxidant and/or aging retardant, wherein transfer of the antioxidant and/or aging retardant to a photosensitive layer laminated on a substrate on said web is substantially eliminated upon using said rubber rollers for a prolonged period of time or at high temperatures.    
     
     
         13 . The apparatus as defined in  claim 12 , wherein said rubber roller is a roller whose surface is coated with rubber.  
     
     
         14 . The apparatus as defined in  claim 12 , wherein the rubber constituting at least the surface of said rubber rollers is selected from at least one of ethylene-propylene rubber and urethane rubber.  
     
     
         15 . The apparatus as defined in  claim 12 , wherein said antioxidant is at least one compound selected from phenol, amine and phosphorous series of antioxidants.  
     
     
         16 . The apparatus as defined in  claim 12 , wherein said rubber rollers which do not substantially contain the antioxidant and/or aging retardant comprise those contacting a surface to be coated or coated surface of said substrate.  
     
     
         17 . The apparatus as defined in  claim 12 , wherein said rubber rollers which do not substantially contain the antioxidant and/or aging retardant are disposed on the side contacting a coating surface of said substrate.