Oki Fax 4580 problem

Does this happen when you perform a test print such as an activity report or config page? if it does you may have a transfer roller issue. The transfer roller is the long black spongy roller directly under the drum, the metal rod in the roller conducts a charge that interacts with the drum. If the roller is dirty (usually chocked up with toner) the necessary charge is diminished and the image will be lighter. You will have to remove the roller in order to clean it, (TURN THE POWER OFF) there is a bendable plastic tab at the right side end of the roller that will release the roller. I personally drench the roller with metho and then wrap a rag around it and squeeze the metho/toner out (dont do this with lexmark rollers, they deform) let dry and give it a try, also check the end of the metal rod and where it connects for contamination.