Electrolytic surface roughening process manner null of aluminum base material for planographic printing edition

摘要

PURPOSE:To obtain a lithographic aluminum substrate hardly staining in a non-printing area and having a high plate wear for a large number of sheets of paper, by a method wherein, a thin layer having a resistance to electrolytic roughening treatment is formed before the electrolytic roughening of an aluminum plate, and then the electrolytic roughening treatment is conducted. CONSTITUTION:A process of forming a thin layer having a resistance to electrolytic roughening on the surface of a cleaned aluminum plate is conducted. As the thin layer, either of an organic film, such as fats and oils, colloidal films and LB film, and an inorganic film, such as oxide films and chemical conversion films, having a relatively high electrically insulating properties can be used. After that, deep pits are generated by an electrolytic roughening treatment. The film is preferably 0.001-0.1g/m2 thick. If less than 0.001g/m2, an effect of forming a deep pit is being reduced. Contrarily, if more than 0.1g/m2, the surface has a larger pit diameter, thus being excessively roughened.