Samsung ML-6512ND-XAA - Manual (Page 82)

Troubleshooting_ 82
4. Pull the duplex unit out of the machine.
5. Locate the jammed paper and remove it.
6. Insert the duplex unit into the slot.
7. Open and close the top cover to resume printing.
If the top cover is not completely closed, the machine will not oper-
ate.
In the optional finisher (stacker & stapler)
Paper jam in front of the finisher
Click this link to open an animation about clearing a jam.
1. Open the finisher’s rear cover.
2. Open the machine’s rear cover.