An injector includes an injector housing and a cartridge door movably mounted to the injector housing between a fully closed position and an open position. A latching mechanism is movable between a latched position, locking the cartridge door to the injector housing in the fully closed position thereof, and an unlatched position, unlocking the cartridge door from the injector housing, thereby enabling movement of the cartridge door toward the open position. The latching mechanism is oriented in the unlatched position when the cartridge door is empty and the latching mechanism is configured to move to the latched position solely when a cartridge is present in the cartridge door and the cartridge door is subsequently moved to the fully closed position thereof.