In office we have this fast HP Color LaserJet CP3505 printer, that should be able to print on both sides. I installed the driver using some GUI (
system-config-printer I think) and everything worked like a charm, except the duplex printing. Trying to enable duplex printing in
kprinter, for example, resulted an error “Some options selected are in conflict” as the Duplex Unit was not installed.
The printer setup can be changed (as instructed in this thread) in the CUPS HTML interface, accessible via any browser:
1) Choose Manage Printers and Set Printer Options of the printer at hand.
2) In Options Installed change radio button to Duplex Unit : Installed.
3) Click Set Printer Options.
You may be asked for a user name and password. Type in your local login user name and password. Sometimes, as in my case, you may need to input
root and the superuser password.
Presumably the same configuration can be done in the GUIs as well, for example:
sudo system-config-printer and tick Duplex Unit in Installable Options tab. (In KDE use
kdesu instead of