| 摘要 |
PROBLEM TO BE SOLVED: To obtain an excellent image without disturbing the image at a transfer processing stage, even when toner remaining quantity in a developing device is reduced to the extent of a almost becoming a state of the toner runs out. SOLUTION: In this device, a remaining quantity detecting means respectively detecting the toner remaining quantity in developing device 4 (4a to 4d), is provided with a comparing means for comparing at least, one of the threshold being preliminarily set, with the detected toner remaining quantity. When performing a primary transfer of the visualized toner image on a photoreceptor drum 1 by the developing device 4 being judged by the comparing means that the toner remaining quantity is reduced across the threshold, the device is allowed, to be applied with the primary transfer bias value being lower than the primary transfer bias in a normal state by a primary bias power source 20. |
