Electrolytic treatment method and apparatus, and method and apparatus for manufacturing planographic printing plate

Abstract

An electrolytic treatment apparatus according to one aspect of the subject matter includes: a transportation device configured to transport a metal plate; an electrolytic bath configured to store an acidic electrolytic solution, wherein the metal plate is transported inside the electrolytic bath; a current supplying device configured to supply an alternating waveform current to continuously subject a surface of the metal plate to an alternating current electrolytic treatment with the alternating waveform current; and a hydroxide ion-adding device installed in an inlet of the electrolytic bath through which the metal plate is introduced into the electrolytic bath, the hydroxide ion-adding device configured to add hydroxide ions (OH − ) on a surface of the metal plate before the surface of the metal plate is subjected to the alternating current electrolytic treatment.

1 . An electrolytic treatment method comprising
 continuously subjecting a strip-shaped metal plate to an alternating current electrolytic treatment with an alternating waveform current in an acidic electrolytic solution while transporting the metal plate therein; and   before the alternating current electrolytic treatment, carrying out a pretreatment step of previously adding hydroxide ions (OH − ) on a surface of the metal plate.   
     
     
         2 . The electrolytic treatment method according to  claim 1 , further comprising
 applying a negative direct current voltage to the metal plate at an inter-electrode distance of 5 to 15 mm to carry out a cathodic reaction in an electrolytic bath in which the alternating current electrolytic treatment is carried out, to form the hydroxide ions.   
     
     
         3 . The electrolytic treatment method according to  claim 2 , wherein
 the cathodic reaction uses a current density of −10 A/dm 2  or lower.   
     
     
         4 . The electrolytic treatment method according to  claim 1 , wherein
 a time interval from at an end of the pretreatment step to at a start of the alternating current electrolytic treatment is 5 sec or less.   
     
     
         5 . An electrolytic treatment apparatus comprising:
 a transportation device configured to transport a metal plate;   an electrolytic bath configured to store an acidic electrolytic solution, wherein the metal plate is transported inside the electrolytic bath;   a current supplying device configured to supply an alternating waveform current to continuously subject a surface of the metal plate to an alternating current electrolytic treatment with the alternating waveform current; and   a hydroxide ion-adding device installed in an inlet of the electrolytic bath through which the metal plate is introduced into the electrolytic bath, the hydroxide ion-adding device configured to add hydroxide ions (OH − ) on a surface of the metal plate before the surface of the metal plate is subjected to the alternating current electrolytic treatment.   
     
     
         6 . The electrolytic treatment apparatus according to  claim 5 , wherein
 the hydroxide ion-adding device is a direct current unit installed in the electrolytic bath and at an inter-electrode distance of 5 to 15 mm from the metal plate, the direct current unit configured to apply a negative direct-current voltage to the metal plate.   
     
     
         7 . A method for manufacturing a planographic printing plate, the method comprising
 an electrolytic surface-roughening treatment step of electrolytically surface-roughening an aluminum plate, wherein   the electrolytic surface-roughening treatment step includes an electrolytic treatment method according to  claim 1 .   
     
     
         8 . An apparatus for manufacturing a planographic printing plate, the apparatus comprising
 an electrolytic surface-roughening treatment apparatus to electrolytically surface-roughen an aluminum plate, wherein   the electrolytic surface-roughening treatment apparatus includes an electrolytic treatment apparatus according to  claim 5 .