Printing Problem Ricoh cl2000N

When we print (either color or black - doesn't matter) there is approximately a 1 in. section about 1/4 of the way from the left that is very faded. Any ideas on what is causing this. We recently replaced the black PCU and Black toner cartridge. It seemed to happen shortly after replace the toner - could it be a bad toner or possibly rollers? If rollers, how do we fix? Thanks