1. Before pulling out the drum unit, place a sheet of paper under the drum unit to catch toner spill.
  2. Make sure that the drum unit is set in position and the drum stay is secured with a screw before the main switch is turned on. If the drum unit is loose, poor contact of the drum connectors may cause electrical noise, resulting in unexpected malfunctions (RAM data change is the worst case).
  3. To prevent drum scratches, remove the development unit before removing the drum unit.