| 摘要 |
PURPOSE:To obtain a minutely roughened surface and prevent contamination of an non-image part in a streak form from occurring, by setting the amounts of Fe, Si and Cu in an aluminum alloy to within respective predetermined ranges and restricting the amount of elemental Si to or below a specified value. CONSTITUTION:An aluminum alloy contains 0.05-1% of Fe, up to 0.2% of Si and up to 0.05% of Cu, the balance being A and unavoidable impurities, with the amount of elemental Si internally distributed being not more than 0.012%. If the Fe content is less than 0.05%, the effects of obtaining finer recrystallized grains and making an electrolytically roughened surface uniform and minutely roughened are slight, whereas if the Fe content is more than 1%, the electrolytically roughened surface will be nonuniform. If the Si content is more than 0.2%, the uniformity of the roughened surface is degraded, and element Si separates out to increase the possibility of contamination of non- image parts. If the Cu content exceeds 0.05%, pits 1 are enlarged in size. By restricting the amount of elemental Si to or below 0.012%, a printing plate can be obtained which hardly generates contamination of non-image parts and has extremely excellent printability. |
