TONER CARTRIDGE IDENTIFYING APPARATUS FOR AN IMAGE FORMING APPARATUS

An image forming apparatus 1 according to the present invention is provided with a replaceable toner cartridge 16. The toner cartridge 16 is provided with a magnetic chip 18 which records identifying information about the type and the like of said toner cartridge as a difference in magnetic resistance, and an identifying means 21 which identifies the type and the like of the toner cartridge 16 by means of the output magnetic resistance detected by the magnetic chip 18 so as to determine the compatibility of the toner cartridge. The magnetic chip 18 is made from magnetic powder and non-magnetic powder compounded at an appropriate ratio at which a predetermined magnetic resistance is maintained. The identifying means 21 is provided with a magnetic sensor 22 which detects magnetic resistance without contacting with the magnetic chip 18, and a microcomputer 23 which verifies whether the output detected by the magnetic sensor 22 is higher than and equal to the predetermined level and within the range of criterion so as to determine whether or not the toner cartridge 16 is compatible with the image forming apparatus.