Image forming machine equipped with an exchangeable developing unit.

摘要

An image-forming machine having an electrostatic latent image-bearing member (2) on which electrostatic latent images will be formed and an exchangeable developing unit (4). The developing unit includes a developing housing 10), a developing agent (34) contained in the developing unit (4) and a developing agent application means (36) for applying the developing agent onto the surface of the electrostatic latent image-bearing member. A counter means (78) is provided that counts the number of times the developing unit (4) has been used and that can be reset. In the developing unit is disposed a developing agent depletion detecting means (68) that detects the depletion of the developing agent. the developing unit further has a reset means (86) that resets the counter means (78) when the use of the developing unit (4) is started. When the developing agent depletion detecting means (68) has detected the depletion of the developing agent, a developing unit exchange signal is formed to indicate that the developing unit be renewed. The developing unit exchange signal is formed even when the counter means has counted a predetermined number that corresponds to the life of the developing unit.