| 摘要 |
PURPOSE:To prevent the staining of a non-image part without lowering printing durability, in preparing an original plate having an O-quinone diazide compound type photosensitive layer, by treating an anodic oxidation film in a dilute alkali solution with pH of 7.5-12 at 60-100 deg.C. CONSTITUTION:After an aluminum plate having a thickness of about 0.1-0.5mm. is subjected to degreasing treatment and succeedingly subjected to sand dressing treatment according to a known method, the treated aluminum plate is subjected to anodic oxidation treatment in a solution with an electrolyte concn. of 1- 80wt% under such a treating condition that a solution temp. is 5-70 deg.C, current density is 5-60A/dm<2>, voltage is 1-100V and an electrolytic time is 10sec- 5min. The aluminum plate having an anodic oxidation film formed thereto is treated with a dilute alkali solution with a concn. of 5-5,000ppm for 5-120sec under such a treating condition that a pH is 7.5-12 and a temp is 60-100 deg.C and, thereafter, an O-quinone azide compound-containing photosensitive layer is applied to the resulting aluminum plate. This photosensitive layer can use a resin soluble in an aqueous alkaline solution as a binder. |
