Try a bit of fingerpoken.
If it's one of those printers where you have access to the print head, then you might like to try disconnecting it from the mains, then after a few secs - after the thing has powered down completely - pushing the head an inch or two to right or left.
The thing should then, on being switched on, realise someone has been messing about, reset the position of the print head and send you a rude message.
Worth a try?
Crossed with Rivets. Oh well...