Comment 3 for bug 885118

There might be several issues here:

1) The Printer Setting tool in Ubuntu 11.10 doesn't show most printer configuration options. The only configuration which the Printer Setting tool exposes to me seems to be the list of allowed users. I cannot configure the availability of a duplex unit, the installed paper trays, paper sizes, etc, using this tool.

My workaround is to set all these options for your printer using the CUPS web interface (http://localhost:631/).

2) The Gnome print dialogs seem to ignore the duplex setting, even if the printer is configured to have a duplex unit. I have added two HP laser printers and they are configured to have a duplex unit, which I checked with the CUPS web interface. The Gnome print dialogs show the duplex options but changing the setting has no effect. Note that the duplex setting in the print dialog of Libre Writer is respected for me. So it really seems to be a Gnome print dialog bug.

My workaround is to set the printers options to always print in duplex mode via the CUPS web interface, since this is what I usually want.

@dejot & Andreas Stöckel: Can you check whether your printer is configured to have a duplexer using the CUPS web interface? Do my other observations also hold for your setup?