Advise please - scumming

I have encountered a rather puzzleling problem - scumming but only on one side of the sheet. The paper stock was turned around, and the scumming problem followed that side, i.e scumming is only encountered on the paper T/S. Although many initiatives have been undertaken, nothing has seemed to help. Any recomendations/comments as to what the problem might be and how to overcome this?

Many thanks

 

well, turning the sheet should not control scumming as the scumming comes from the plate being inked up were it shouldnt be, irrespective of the side of the sheet, so i doubt htis is actually scumming because the plate doesnt know you've just turned a pallet and feeding it through again

its a strange one, or im misunderstanding what you mean?

 

Print job done on Heilelberg Heat set web off-set press - scumming on top of of the sheet only, as the bottom printed perfectly. After numerous interventions, the sheet was eventually turned around and scumming then only occured on the bottom.

 

Note: duplicate thread running there -> http://www.colorprintingforum.com/web-press/advise-please-scumming-3050.html

Let's consolidate the discussion into that thread.