Image forming apparatus having toner depletion detection feature

摘要

An image forming apparatus usable with a process cartridge for forming an image on a recording material. The process cartridge includes an image bearing member, and at least one developing device for developing a latent image formed on the image bearing member with a developer. Each of said at least one developing devices includes a developer accommodating device for accommodating a respective developer to be used in said at least one developing device. The image forming apparatus includes a mounting device for mounting the process cartridge, an auxiliary developing device exterior to the process cartridge for developing a latent image formed on the image bearing member with a developer, the auxiliary developing device including an auxiliary developer accommodating device for accommodating the developer to be used in the auxiliary developing device, and a detecting device for detecting a respective predetermined level of developer in the auxiliary developer accommodating device and in each of the respective developer accommodating devices of said at least one developing device.