| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the nonuniformity corresponding to the frequency generated on the surface of an aluminum web at the time of electrolytically etching the web to produce the support for a lithographic printing plate and to conduct the etching at a high speed and a high current density. SOLUTION: A metallic web 1 is passed through pass rollers 2, 4 and wound on a drum roller 3. Electrodes 5 and 6 are concentrically provided outside the drum roller 3. One output terminal of an alternating waveform power source 13 is connected to a contact feeder roller 7 and the other to the electrodes 5 and 6, and a voltage is impressed. A frequency setter 15 for optionally setting the frequency is housed in the alternating waveform power source 13. In electrolysis, a frequent hardly causing nonuniform treatment is selected in consideration of the metallic web 1 treating speed, current density, etc., and the frequency is controlled to the selected frequency by the frequency setter 15.
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