Unit and method for corona treatment

Abstract

Method for corona treatment using an apparatus having a corona treatment unit with an inlet side and an outlet side, one or more sets of transverse electrodes, at least one electrode in each set being connected to a high voltage source and at least one second electrode connected electrically to ground, wherein the second electrode connected to ground includes a rotatable roller. The method involving through-flow corona treatment of sheet material, the material being conveyed via a mechanical conveyor means. By such a solution sheets of material can be conveyed and corona-treated without holding the material and pulling it through the apparatus.

I claim: 
     
         1 . A process for corona treatment with an apparatus for corona treatment including a corona treatment unit with an inlet side and an outlet side, wherein the unit includes at least one set of transverse electrodes, at least one first electrode in each set being connected to a high voltage source and at least one second electrode connected electrically to ground, wherein the second electrode connected to ground comprising a transversely extending rotatable roller, where the process comprises performing corona treatment on sheet material, the sheet material being conveyed mechanically from the inlet side towards the outlet side of the corona treatment unit between the at least one electrode connected to high voltage and the at least one second electrode, and the sheet material being passed over the transversely extending rotatable roller of the at least one second electrode. 
     
     
         2 . The process for corona treatment according to  claim 1 , wherein air is sucked in via a gap formed between the transversely extending rotatable roller of the at least one of said transverse electrodes and a supporting surface arranged at at least one side of the rotatable roller. 
     
     
         3 . The process for corona treatment according to  claim 1 , where the at least one first electrode comprises at least two transverse electrodes, each of the transvers electrodes being connected to a high voltage. 
     
     
         4 . The process for corona treatment according to  claim 2 , wherein at least one suction box connected to a suction device is used for the sucking in of air via said gap. 
     
     
         5 . The process for corona treatment according to  claim 4 , wherein said air is sucked in through a screen. 
     
     
         6 . The process for corona treatment according to  claim 1 , comprising the further steps of detecting passage of sheets with at least one sensor that is connected to control means, and interrupting said high voltage for the first electrodes when no sheets are detected. 
     
     
         7 . The process for corona treatment according to  claim 1 , comprising the additional step of applying at least one of ink and lacquer to the sheets preliminary to the corona treatment. 
     
     
         8 . The process for corona treatment according to  claim 1 , comprising the additional step of applying at least one of ink and lacquer to the sheets after the corona treatment. 
     
     
         9 . The process for corona treatment according to  claim 1 , wherein the sheet material being treated comprises a plurality of separate sheets.