On your previous post about ink on drum, I gave you the PN for the Drum Maintenence Plate. If this has not fixed your problem, there may be other issues.
A drum is not the problem.
Find a good Tech! I have spent a lot of time and money to be an authorized Xerox Tech for most of their products.
I do not mind giving advise on things that most of you can do, but major repairing, requires a lot of talent!
Besides print quality issues , are there any errors?