Brother MFC-420CN - Manual (Page 126)

11 - 7 TROUBLESHOOTING AND ROUTINE MAINTENANCE
Paper is jammed inside the MFC
1
Remove the jam clear cover. Pull the jammed paper out of the
MFC.
2
Re-insert the jam clear cover.
3
If you can not pull out the jammed paper, lift the scanner cover
from the right-hand side of the MFC until it locks securely into
the open position.
4
Remove the jammed paper.
If the paper is jammed underneath the print head, disconnect
the MFC from the power source so you can move the print head
to take out the paper.
Jam Clear Cover
Scanner Cover