Grabbing on what Kimzi said, do a simple test to find where is the origin:
- do a copy and listen the paper
- Open the front door before the paper passes the fuser. You may need to try a few times until accomplish.
- Check the paper and see if the ghost is happening before the fuser. If yes is a drum problem, if no is a fuser problem.
According to what I understand it could be either the fuser, drum or the decharge lamp.
Print out a page, take out the fuser and see if you can find a defect on it, do the same on the drum.
I'm not familiarized with this model, but sounds like you have a problem in the fuser. Do you know if Is too old?