Brother MFC-8420 User Manual page 367

1
Pull the paper tray completely out of the MFC.
2
Pull the jammed paper up and out of the MFC.
3
Press the cover release button and then open the front cover.
4
Pull out the drum unit assembly. Pull the jammed paper up and
out of the MFC. If you cannot remove the drum unit assembly
easily at this time, do not use extra force. Instead, pull the edge
of the jammed paper from the paper tray.
22 - 7 TROUBLESHOOTING AND ROUTINE MAINTENANCE