| 摘要 |
PROBLEM TO BE SOLVED: To upgrade plate wear resistance and printing performance by roughing a support material made of aluminum or the like by chemical roughing, and specifying a ratio of maximum surface roughness before and after the roughing of the material, thereby upgrading dampening water retentivity at the time of offset printing. SOLUTION: A support for a lithographic printing plate is manufactured by degreasing support material made of aluminum or an aluminum alloy by solvent cleaning, then chemically roughing it, and roughing it so that a ratio of maximum surface roughness (Rmax) before and after the roughing becomes 1.2 times or more. A method for chemically roughing is a method for roughing by dipping it in water solution of acid or base and eroding a surface. As example of the base, an inorganic alkali salt such as sodium hydroxide, sodium carbonate or the like is used. of them, a water solution of an inorganic alkali salt is suitable, and its concentration is suitably 1 to 50 wt.%. |
