METHOD FOR DETECTING RESIDUAL AMOUNT OF DEVELOPER IN PROCESS CARTRIDGE, PROCESS CARTRIDGE AND IMAGE FORMING APPARATUS ENABLING PROCESS CARTRIDGE TO BE ATTACHED/DETACHED

PROBLEM TO BE SOLVED: To provide a method for detecting the residual amount of developer in a process cartridge by which the residual amount of the developer is exactly detected even when an image forming apparatus is replaced to the one having a different processing condition in the midst of its service, and to provide a process cartridge and an image forming apparatus to/from which the process cartridge can be attached/detached. SOLUTION: The process cartridge has a storage medium 20, which has an area 20a for storing information to specify the image forming apparatus to which the process cartridge is attached, and an area 20b for storing correction value information to detect the amount of the developer in the process cartridge. When the information to specify the image forming apparatus, which is read out from the storage medium, is different from the information to specify the present apparatus, the control part 22 of the image forming apparatus changes the correction value information to detect the amount of the developer, which is read out from the storage medium, by a conversion coefficient 24a corresponding to the present apparatus and the previous image processing device, and calculates the residual amount of the developer by using the correction value information to detect the changed amount of the developer. COPYRIGHT: (C)2006,JPO&NCIPI