We have developed a new toner replenishment system that automatically decreases volume of the toner cartridge by using the screw pump while supplying the toner to the developing device.The Auto Volume Decreasing Soft Toner Cartridge is a the plastic bag, which is made of thin, flexible, plastic film, and the volume of the toner cartridge decreases gradually with toner consumption.This technology enables the resource saving, the reduction of disposal cost due to the volume reduction, and the very easy exchange of the toner cartridge.