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US 4,445,998 AGranted
Method for producing a steel lithographic plate
AssigneeToyo Kohan Co., Ltd.
InventorsKatsumi Kanda, Katsunobu Kunimoto, Keiji Yamane, Yoshikazu Kondo
Life of this patent
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Abstract
A method for producing a metal substrate for a lithographic plate is provided herein by treating the substrate having the thickness in the range of 50 to 400 .mu.m. The said substrate is electrochemically, chemically or mechanically treated in order to provide an average surface roughness in the range of 0.1 to 3 .mu.m, followed by a surface treatment such as plating or chemical treatment, and then followed by a conventional hydrophilic treatment.
Claims12
A method for producing a steel lithographic plate which consists essentially of:
- (a) subjecting a steel substrate having a thickness in the range of 50 to 400 cm, to a graining treatment by (i) electroplating with iron, (ii) etching in a solution containing ferric ions or (iii) mechanical treatment with sand or marble, in order to impart to said substrate an average surface roughness in the range of 0.1 to 3 .mu.m,
- (b) imparting improved corrosion resistance to the substrate of step (a) by plating with a metal, an alloy or multi-layer of metals, and then
- (c) applying a hydrophilic coating with a suspension containing a water-dispersible sol of a metal compound to the treated substrate of step (b).
Dependencies are inferred from the claim text.