An imaging unit for an electrophotographic image forming device includes a housing having a rotatable photoconductive drum. A frame at a rear of the housing is positioned to matably receive a toner cartridge and is open to a portion of an outer surface of the photoconductive drum. An electrical contact is positioned along a first side wall of the frame for contacting a corresponding electrical contact in the image forming device and is electrically connected to processing circuitry on the housing. The electrical contact of the imaging unit faces upward and is unobstructed from above. A cam surface is positioned along an inner side of the first side wall of the frame for contacting an electrical connector of the toner cartridge and moving the electrical connector of the toner cartridge from a retracted position to an operative position upon mating of the toner cartridge with the imaging unit.