I had the same problem i will try what you suggested
Try modyinf the brightess or darkness when copying:
We just installed a new workcentre 6015ni. If I print from a MAC or PC, the print quality looks great. However, If i take any of the printed pages and copy it - by placing it on the platen glass and selecting COPY - the quility of the copy is not as good - there are areas of ghosting on the bottom left and in the middle of the page. I know the paper path and toner and other items are clean, because the printer is new and prints cleanly. What could be causing problems with copies? the platen glass looks clean. Could there be an issue with the auto exposure? or do I have a defective machine?