To provide an image forming apparatus using a detection means capable of accurately detecting toner concentration or the like over a predetermined range even when tolerance exists in a detection means for detecting toner concentration or the like.
The image forming apparatus is equipped with two developer conveying and stirring augers arranged at positions lower than a developing roll and conveying and stirring two-component developer stored inside a developing device, a toner supply part for supplying toner to one end of the developer conveying and stirring auger, and the detection means provided at a position on an opposite side to the toner supply part in the shaft direction of the developer conveying and stirring auger and lower than the shaft of the developer conveying and stirring auger and detecting the toner concentration in the two-component developer according to magnetic permeability. The developer conveying and stirring auger is set so that the outside diameter of the toner supply part may be smaller than that at other parts.
KATO MASANORI
YOSHIKAWA SHUJI
KOIZUMI TERUAKI
MATSUI YOJI
Katsuo Naruse
Masahiro Koizumi
Aoya Kazuo
Masashi Torino