Every since we got the universal binary version of Quark (v7.01) we have had trouble printing to our EFI/Canon rips. After speaking to Quark it wasn't actually a Quark issue, but a CUPS problem within 10.4. Today, EFI have released a CUPS update. You can download it here.

I haven't had time to try it out. Hopefully tomorrow. Will blog the answer as soon as I have tested it.