We have a couple of HP2800s around our school. The problem is the kids keep on messing with the two paper trays (A4 tray and A3 tray) and generally being a pain with these printers. We just want to see if there is anyone out there with a solution? We want to fill up the printer with A4 and A3 Paper (No rubbish ripped paper!) lock it and leave it so they can mess around with it.