Image forming apparatus having a removable processing unit

摘要

An electrophotographic copier or similar image forming apparatus having a photoconductive drum and a developing unit having a developing roller which is pressed against the drum. The developing unit is removably mounted on a body of the apparatus and arranged such that reaction forces exerted in the vertical direction by the copier body on the developing unit are directed upward at all times. When the pressing contact of the developing roller with the drum is cancelled, the developing unit is held in a retracted position where it is spaced apart from the drum.