| 摘要 |
PROBLEM TO BE SOLVED: To improve ink removability and water retentivity by an method wherein an aluminum support, which has surface shape having a roughness index of a specified value and the center-line mean roughness of the surface of which has a specified value, is formed. SOLUTION: As a support for lithographic printing plate excellent in ink removability and water retentivity, an aluminum support, which has surface shape having a roughness index X of 0.45 or less and, at the same time, the center-line mean roughness of the surface of which is 0.40μm or more, is employed. In this cased, X=[Ra×Rv/(Sm)<2>×100, in which Ra is the center-line mean roughness, Rv is the distance between the maximum valley and mean line in the reference length of profile curve and Sm is the interval between peaks in the reference length. Aluminum plate includes a pure aluminum plate and a aluminum alloy plate. As the aluminum alloy plate, various plates, which is made of an alloy of aluminum and metals such as Si, Cu, Mn, Mg, Cr, Zn, Pb, Bi, Ni, or the like, are employed.
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