IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To provide an image forming apparatus in which toner supply failure when replacing a toner cartridge with a new one is reduced without using a high torque motor. SOLUTION: The image forming apparatus conveys toner by rotating a conveying screw 32 in a toner cartridge. The image forming apparatus includes a driving source 102 reversely rotatable; a first driving force transmitting section that transmits the driving force of the driving source 102 to the conveying screw 32; a second driving force transmitting section that transmits the driving force of the driving source 102 to the conveying screw 32 at torque higher than that used in the first driving force transmitting section; and a driving force transmission switching section that switches the rotating direction of the driving source 102, thereby switching the transmission of driving force from the driving source 102 to the first or second driving force transmitting section. When toner is conveyed to be supplied, the conveying screw 32 is rotated via the first driving force transmitting section. Alternatively, when at least the toner cartridge is replaced with a new one, the conveying screw 32 is rotated via the second driving force transmitting section. COPYRIGHT: (C)2009,JPO&INPIT