| 摘要 |
PURPOSE:To make a printing plate having good printability without generating doctor stripe, by carving an image in the surface of a printing plate material by mechanical carving and subsequently applying an etching solution to the entire surface thereof to etch the same so as to obtain such a state that acute-angle parts are not present on at least the surfaces of the carved parts. CONSTITUTION:Copper plating is applied to the surface of a cylinder for gravure printing and, subsequently, an image is carved in the plated surface according to a usual method. Next, an etching solution is applied to the entire surface of the cylinder using a roller. As the etching solution, a ferric chloride solution is used and the temp. thereof is held to a range of 20-30 deg.C and etching is performed for 20-30 sec under a humidity condition of 40-60%. The finish point of etching is set to the point of time when acute-angle parts are removed from the carved parts. A state free from the acute-angle parts 2 means such a state that the diameter of the upper part of the protruding part 1 of each acute-angle part becomes 2-4mum and, when the diameter is 2mum or less, smoothness is insufficient and, when the diameter is 4mum or more, effect is exerted on an image or on the coating amount in the case of a solid plate. After etching is finished, the etching solution is immediately washed off and, subsequently, puff polishing is applied to the cylinder and chromium plating is applied to the entire surface thereof.
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