Abstract: A thermal ink jet printhead for a printer has a temperature sensor attached thereto for monitoring the operating temperature thereof. A maximum printhead operating temperature is stored in a memory of the printer's control circuitry and, if the printhead temperature sensed by the temperature sensor during a printing operation exceeds the maximum operating temperature stored is the memory, a signal is generated indicating that the printhead has stopped ejecting ink droplets and must be checked for depriming or a depleted ink supply.

Abstract: An apparatus which transfers a developed image from a photoconductive surface to a copy sheet. The apparatus includes a corona generating device arranged to charge the copy sheet. This establishes a transfer field that is effective to attract the developed image from the photoconductive surface to the copy sheet. A sheet guide, adapted to have a portion thereof contiguous with the corona generating device, maintains the copy sheet substantially wrinkle free as it is being guided into contact with the photoconductive surface in the transfer field.