Oki B401dn User Manual page 72

10. Check for paper jam in duplex unit.
> Remove the Image Drum as described in step
by raising the coloured handles (2) on each side, and then by holding the handles
and gently lifting it out.
2
1
> Remove any paper and replace the duplex unit.
> Re-install the image drum as described in step
11. Check for paper jam under the Paper Guard.
> Remove the Image Drum as described in step
3,
2
5
3
Troubleshooting > 72
then, remove the Duplex unit (1)