hplip is an opensource project to support multiple HP printers on Linux. On Ubuntu 12.04 I already had this installed, but running ‘sudo hp-setup’ gave me this error:
kev@ubuntu:~$ sudo hp-setup HP Linux Imaging and Printing System (ver. 3.12.2) Printer/Fax Setup Utility ver. 9.0 Copyright (c) 2001-9 Hewlett-Packard Development Company, LP This software comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome to distribute it under certain conditions. See COPYING file for more details. warning: Qt/PyQt 4 initialization failed. error: hp-setup requires GUI support (try running with --qt3). Also, try using interactive (-i) mode.
A quick Google turned up this post, and installing hplip-gui installed the missing libraries and got me up and running.
sudo apt-get install hplip-gui
Starting up hp-setup again and following the wizard to point to the IP of my printer was all I needed to get my printer working.