Patent ID: 8818215

Claim:
An image forming apparatus comprising: a plurality of image forming portions each including an image bearing member, a developing device for developing into a developer image an electrostatic latent image formed on the image bearing member, and a cleaning device for collecting in an accommodating container a developer remaining on the image bearing member after the developer image is transferred, wherein said plurality of image forming portions are provided along a movement direction of a recording material conveying member for conveying a recording material onto which the developer image is to be transferred or an intermediary transfer member onto which the developer image is to be transferred, and include a first image forming portion and a second image forming portion provided downstream of the first image forming portion with respect to the movement direction of the recording material conveying member or the intermediary transfer member; detecting means for detecting information on a developer deterioration state at the first image forming portion; storing means for storing a relationship between a detection result of said detecting means and an amount of developer to be back-transferred at the second image forming portion; and an outputting device for outputting a signal relating to an amount of developer accommodated in the accommodating portion at the second image forming portion on the basis of a detection result of said detecting means, the relationship stored in said storing means, information on a developer used for image formation at the first image forming portion, and information on a developer used for image formation at the second image forming portion.