There are two(2) user changeable consumables, the toner and drum(OPC). the drum is the mylar looking portion, if it slightly "scratched" or worn as a streak, that comes out as faded printing or missing print. That seems what your description offers, so change that too. These last only so long and suggest you clean the immediate as well of spilled toner and general area of paper path.

tada -----Willy Happy