Did you try any tests on Ubuntu printing to the CD/DVD tray on a CD/DVD? I don't see any there. It appears all of your tests passed. What does installing the printer though CUPS vs hp-toolbox have to do with it?
Did you try any tests on Ubuntu printing to the CD/DVD tray on a CD/DVD? I don't see any there. It appears all of your tests passed. What does installing the printer though CUPS vs hp-toolbox have to do with it?