Brother MFC620CN Service Manual page 208

Removing the PF encoder disk, ejection idle gear and paper feed motor
(13) Peel off the PF encoder disk from the PF roller gear only when it should be replaced.
NOTE: Once removed, the PF encoder disk will become unusable and a new disk will have to
be put back in.
NOTE: Remove any adhesive remaining left on the PF roller gear.
(14) Remove the ejection idle gear.
PF encoder disk
PF roller gear L
PF motor/sensor PCB
harness
Ejection idle gear
5-70
Engine unit
Paper feed roller
Confidential