Color image forming apparatus

摘要

An image forming apparatus in which a process cartridge contains at least an image carrying member, a developing unit and a developer replenishment unit. The process cartridge can be mounted to or removed from the apparatus for its replacement. The process cartridge can take a first position where images can be formed and a second position where developer can be replenished. The process cartridge can be moved from the first position to the second position when a detector for detecting the depletion of the developer outputs a detection signal.