Trouble Shooting
| Step | Cause | Solution | Parts |
| 1 | Toner usage remain maybe low. | Replace toner cartridge | Toner 6K (015-0296-21) 10K (015-0297-21) |
| 2 | TR(transfer roller) of the drum unit spring deformed. | Replace the drum unit. | Drum (015-0289-21) |
| 3 | TR(transfer roller) of the drum unit does not rotate smoothly (see below). | Clean TR. |
Clean TR
Loosen 3 fixing screws to remove the metal frame. Check the Transfer roller position and confirm whether there are any foreign object.
