Patent ID: 7192689

Claim:
A process for manufacturing an aluminum support for a planographic printing plate material, the process comprising the steps of: electrolytically surface-roughening an aluminum plate in an electrolytic solution, employing a sinewave alternating current; and anodizing the surface-roughened aluminum plate; the electrolytically surface-roughening step comprising a first stage of electrolytically surface-roughening the aluminum plate in a first electrolytic solution containing hydrochloric acid as a main component at a current density of D 1 (A/dm 2 ) for t 1 (second) at a quantity of electricity of Q 1 (C/dm 2 ) and a second stage of electrolytically surface-roughening the aluminum plate in a second electrolytic solution containing hydrochloric acid as a main component at a current density of D 2 (A/dm 2 ) for t 2 (second) at a quantity of electricity of Q 2 (C/dm 2 ), the first stage being followed by the second stage, wherein D 1 is from 40 to 100 A/dm 2 , a ratio of D 1 to D 2 is from 1.3:1 to 7:1, a ratio of t 1 to t 2 is from 1:1 to 5:1, and the total electric quantity Q (Q 1 +Q 2 ) is from 600 to 1500 C/dm 2 .