| 摘要 |
A method of producing an aluminum base sheet for printing plates is shown. The improvement comprises three steps in sequence including electrolytically graining the surface of the aluminum sheet by exposing it to a chemical etching bath comprising a chloride containing electrolytic solution and impressing a current on the sheet; thereafter cathodically cleaning the grained sheet by exposing it to a concentrated solution of sulfuric acid and again impressing a current on the sheet; and finally anodizing the cathodically cleaned sheet by exposing it to a second concentrated solution of sulfuric acid and imposing a current on the sheet. In the preferred embodiment, the electrolytic graining is carried out in the presence of hydrochloric acid and in an alternating current; and the cathodic cleaning and anodizing steps are carried out in sulfuric acid and in a direct current. In the preferred embodiment of the invention a web of aluminum is continuously moved through three treating baths in series. |
