Method of manufacturing lithographic printing plate support

Abstract

Disclosed is a method of manufacturing a lithographic printing plate support, including a step of subjecting an aluminum plate to at least: a mechanical graining treatment using a brush and a slurry containing an abrasive to carry out mechanical graining such that the average surface roughness R a is 0.25 μm or more but less than 0.40 μm, and an electrochemical graining treatment for carrying out electrochemical graining in an aqueous solution containing hydrochloric acid such that the average surface roughness R a is 0.40 to 0.55 μm, with the treatments being performed in this order, so as to obtain a lithographic printing plate support. By this method, a lithographic printing plate support which can be used for a presensitized plate of high sensitivity which has both an excellent scumming resistance and a good press life when made into a lithographic printing plate is obtained.

1 . A method of manufacturing a lithographic printing plate support, comprising a step of subjecting an aluminum plate to at least: 
 a mechanical graining treatment using a brush and a slurry containing an abrasive to carry out mechanical graining such that the average surface roughness R a  is 0.25 μm or more but less than 0.40 μm, and    an electrochemical graining treatment for carrying out electrochemical graining in an aqueous solution containing hydrochloric acid such that the average surface roughness R a  is 0.40 to 0.55 μm,    with the treatments being performed in this order, so as to obtain a lithographic printing plate support.    
     
     
         2 . A method of manufacturing a lithographic printing plate support, comprising a step of subjecting an aluminum plate to at least: 
 a mechanical graining treatment using a brush and a slurry containing an abrasive to carry out mechanical graining such that the average surface roughness R a  is 0.25 μm or more but less than 0.40 μm,    an first etching treatment in an aqueous alkali solution,    an electrochemical graining treatment for carrying out electrochemical graining in an aqueous solution containing hydrochloric acid such that the average surface roughness R a  is 0.40 to 0.55 μm,    an second etching treatment in an aqueous alkali solution,    an electrochemical graining treatment in an aqueous solution containing hydrochloric acid,    an third etching treatment in an aqueous alkali solution, and    an anodizing treatment,    with the treatments being performed in this order, so as to obtain a lithographic printing plate support.    
     
     
         3 . The method of manufacturing a lithographic printing plate support according to  claim 2 , wherein a desmutting treatment is performed subsequent to at least one of the first etching treatment in an aqueous alkali solution, the second etching treatment in an aqueous alkali solution and the third etching treatment in an aqueous alkali solution.