HP Printer reports "missing cartridge (1048)"
I can't print anything and have been unable to for a couple of weeks. The printer is an HP Photosmart D6160 and I am running Ubuntu 12.04. I have tried removing the printer and setting it up again, removing and replacing the cartridges, turning it off and on again (!) but I have run out of ideas. It does not even tell me which cartridge it thinks is missing. I can see them and they are all most definitely there.
It worked fine on 10.04 but having upgraded to 12.04 a few months ago, the printer has become very tempermental.
Any suggestions hugely welcome