I might install Mint 17 in Vbox if I can't print.
I've just plugged my printer and I know my PC knows it's been plugged. I can't see it via lsblk, some other commands I could use? I'll manually add it via USB id or something similar.
Have you checked h-node.org for hardware compatibility.
I am a member!
"I might install Mint 17 in Vbox if I can't print." - is this a threat? Of course you can do whatever you want to, but by using trisquel, you agreed to know that hardware issued might occur because of the lack of free drivers available. If you cannot live with that, you propably don't want to use it.
Back to your question: lsusb might help. You should also provide some more details, like printer model etc.
HP Deskjet Ink Advantage 3525
That printer can perfectly work: http://hplipopensource.com/hplip-web/models/deskjet_aio/deskjet_3520_series.html
However, it requires a more recent version (3.12.6 or later) of HPLIP than the one in Trisquel 6's repository (3.12.2).
You may want to early adopt Trisquel 7: http://devel.trisquel.info/makeiso/iso/
Otherwise, install that .deb of a more recent version of HPLIP: http://packages.ubuntu.com/precise-backports/hplip
That .deb requires some dependencies (GDebi will indicate them) that you would also have to download from the precise-backports section of http://packages.ubuntu.com
Ah might as well wait for 7 then, thanks! :D