1. Hit additional functions key.
2. Hit # key.
3. Arrow to number 7, Printer and hit Set.
4. Arrow to number 4, Printer Re-Set and hit Set.
5. Yes, re-set printer (hit minus key - back arrow)
6. Unplug machine and plug it back in.
Worked for me on D780.
WisGolfNut, February 2013