Patent ID: 8774648

Claim:
An image forming apparatus comprising: a cartridge detachably mountable to a main assembly of the image forming apparatus, said cartridge including a developer accommodating portion for accommodating a developer, and an operation member; a remaining amount detector for detecting a remaining amount of the developer in said developer accommodating portion when an image forming operation is not carried out while said operation member is in operation; an operation amount detector for detecting a cumulative operation amount of said operation member; and a setting device for setting, on the basis of the remaining amount of developer detected by said remaining amount detector and the cumulative operation amount of said operation member detected by said operation amount detector, timing of subsequent remaining amount detection of said remaining amount detector, wherein said remaining amount detector provides a remaining amount ratio of the developer remainder to a maximum accommodation capacity of said developer accommodating portion, said operation amount detector provides an operation amount ratio of a remaining operation amount until an end of the service life from the detection of said cumulative operation amount to a total operation amount until the end of the service life from an initial state of said operation member, and said setting device sets the timing on the basis of a comparison between the remaining amount ratio and the operation amount ratio.