Matt has the solution!  Great work!

Have you tried the HPIJS drivers that are packaged for OS X? You can get them at http://www.linuxfoundation.org/collaborate/workgroups/openprinting/macosx/hpijs. Be sure to also download and install Foomatic-RIP and Ghostscript. These drivers should support your printer.

via Apple – Support – Discussions – Deskjet 5650.