Printer problem

When you add toner to the machine, they tell you to clean the charge wire by running a green lever back and forth across the corona assy.
If you do not get it back into home position, it makes a shadow, resulting in a black line.
It happens all the time.

There is a green lever inside on the process unit(the one where you put the toner onto). Just move this lever from right to left and back and see that it clicks when you put it back to home position and the continuous line from top to bottom should vanish. If not, take the process unit out of the printer and do the above procedure a couple of times. Actually once I also found a small cockroach burnt up inside there(called the main charger assy).

It sounds like you need to replace the developer unit, which can be quite costly.