Have you tried removing the printer software (driver, configuration applications, anything else connected to the printer), restarting, then reinstalling it all and restarting again? It sounds like some part of the printer software is messed up and needs to be fixed, so removing it and then reinstalling it are the way to go. Also, by restarting after removing the software and after reinstalling it, you make sure that there are no "leftover" chunks of the software automatically loaded on startup that could cause problems.