Copper plating method and apparatus for a gravure cylinder

Abstract

The present invention provides a copper plating method and apparatus for a gravure cylinder in which copper plating with more uniform thickness can be provided over a full length of a gravure cylinder without causing defects such as rashes and pits irrespective of a size of the gravure cylinder, concentration of a copper plating solution can be managed automatically, a consumption amount of an additive is reduced to make it possible to perform a plating treatment within a short period of time, a power supply cost is reduced, and handling is easy with excellent visibility. A gravure cylinder in a hollow cylindrical shape is held at both ends in a longitudinal direction. The gravure cylinder is accommodated in a plating bath filled with a copper plating solution. The gravure cylinder is energized so that the gravure cylinder functions as a cathode while being rotated at a predetermined speed. A pair of anode chambers in a long box shape, in which insoluble anodes are provided upright slidably to both sides of the gravure cylinder in the plating bath and energized so as to function as an anode, are brought close to both side surfaces of the gravure cylinder at a predetermined interval. Copper plating is provided on an outer peripheral surface of the gravure cylinder.

1 . A copper plating method for a gravure cylinder, comprising:
 holding a gravure cylinder in a hollow cylindrical shape at both ends in a longitudinal direction;   accommodating the gravure cylinder in a plating bath filled with a copper plating solution;   energizing the gravure cylinder so that the gravure cylinder functions as a cathode while being rotated at a predetermined speed;   bringing a pair of anode chambers in a long box shape, in which insoluble anodes are provided upright slidably to both sides of the gravure cylinder in the plating bath and energized so as to function as an anode, close to both side surfaces of the gravure cylinder at a predetermined interval; and   providing copper plating on an outer peripheral surface of the gravure cylinder.   
   
   
       2 . A copper plating method for a gravure cylinder according to  claim 1 , wherein a cation exchange film is provided on a side surface of the anode chamber on the gravure cylinder side. 
   
   
       3 . A copper plating method for a gravure cylinder according to  claim 1 , wherein the anode chamber has a length equal to or larger than a full length of the gravure cylinder in a longitudinal direction. 
   
   
       4 . A copper plating method for a gravure cylinder according to  claim 1 , wherein an inside of the anode chamber is filled with an acidic electrolyte solution, a liquid amount in the anode chamber is measured, and in a case where the liquid amount is insufficient, water is supplied. 
   
   
       5 . A copper plating method for a gravure cylinder according to  claim 1 , wherein the cooper plating liquid contains copper sulfate, sulfuric acid, chlorine, and an additive, a specific gravity and a sulfuric acid concentration of the copper plating solution are measured, in a case where the specific gravity is too high, water is supplied, and in a case where the sulfuric acid concentration is too high, cupric oxide powder is supplied. 
   
   
       6 . A copper plating method for a gravure cylinder according to  claim 1 , wherein the copper plating solution is obtained by removing impurities with a filter. 
   
   
       7 . A copper plating method for a gravure cylinder according to  claim 1 , wherein the predetermined interval is 1 mm to 50 mm. 
   
   
       8 . A copper plating apparatus for a gravure cylinder that provides an outer peripheral surface of a gravure cylinder with copper plating, comprising:
 a plating bath filled with a copper plating solution;   chuck means for holding the gravure cylinder in a hollow cylindrical shape at both ends in a longitudinal direction so that the gravure cylinder is capable of being rotated and energized, and accommodating the gravure cylinder in the plating bath; and   a pair of anode chambers in a long box shape which are provided upright slidably to both sides of the gravure cylinder in the plating bath and in which an insoluble anode energized so as to function as an anode is provided.   
   
   
       9 . A copper plating apparatus for a gravure cylinder according to  claim 8 , wherein a cation exchange film is provided on a side surface of the anode chamber on the gravure cylinder side. 
   
   
       10 . A copper plating apparatus for a gravure cylinder according to  claim 8 , wherein the anode chamber has a length equal to or larger than a full length of the gravure cylinder in a longitudinal direction thereof. 
   
   
       11 . A copper plating apparatus for a gravure cylinder according to  claim 8 , wherein an inside of the anode chamber is filled with an acidic electrolyte solution, and the apparatus further comprises an anode chamber liquid amount supply mechanism that measures a liquid amount in the anode chamber and supplies water in a case where the liquid amount is insufficient. 
   
   
       12 . A copper plating apparatus for a gravure cylinder according to  claim 8 , wherein the copper plating solution contains copper sulfate, sulfuric acid, chlorine, and an additive, and the apparatus further comprises a copper plating solution automatic control mechanism that measures a specific gravity and a sulfuric acid concentration of the copper plating solution, and supplies water in a case where the specific gravity is too high and supplies cupric oxide powder in a case where the sulfuric acid concentration is too high. 
   
   
       13 . A copper plating apparatus for a gravure cylinder according to  claim 8 , further comprising a filter that removes impurities in the copper plating solution.