| 摘要 |
PURPOSE: To produce a photosensitive planographic printing plate having excellent plate making performance, such as sensitivity and exposed visible image characteristic, by subjecting the printing plate to a pretreatment, electrolytic surface roughening treatment, desmutting treatment and anodic oxidation under specific conditions. CONSTITUTION: An aluminum sheet is subjected to the pretreatment to execute alkaline etching at an aluminum melting rate in a range of 1 to 5g/m<2> and is then subjected to the electrolytic surface roughening treatment in an electrolytic bath mainly composed of a nitric acid. This sheet is subjected to the desmutting treatment to execute the alkaline etching at the aluminum melting rate in a range of 0.5 to 2g/m<2> . The sheet is then subjected to the anodic oxidation in the electrolytic bath mainly composed of a sulfuric acid. The treatment conditions for the alkaline etching of the pretreatment, etc., are specified to a bath concn. of 60±10g/l, a bath temp. of 85±10 deg.C and treatment time of >=3 seconds. The desmutting conditions are respectively specified to 9±2g/l and 70±5 deg.C, and >=3 seconds. The surface of the substrate (treated sheet) may be provided with a photosensitive layer contg. a quinone diadize compd. by treating the sheet in a treating bath contg. ammonium after the anodic oxidation treatment. As a result, the photosensitive planographic printing plate having excellent printability, such as staining resistance and plate wear, is provided. |
