Issue:

Papers appear to have a black line or streak over toner when printing or copying.

Solution:

Insert a blank sheet of paper atop the printer, make around 20 copies. This should help clean out lose toner or smears from within the printer.

OR

Remove and reinstall the drum cartridge:

1. Open the front and left side door (Door A) of the printer.
   
   
    

2. Unlock the drum cartridge by pushing the lever right to the unlocked position.
   
   
    

3. Grasp the handle for the drum cartridge and pull it out of the printer.
   
   
   
   CAUTION: Do not leave the drum exposed to light for more than 5 minutes.
    

4. Slide the drum cartridge back into the machine. You will hear it click into position.
   
   
    

5. Lock the drum cartridge by pushing the lever left to the locked position.
   
   
    

6. Close the front and left side doors.