| 摘要 |
PURPOSE:To always detect accurately and stably toner density by isolating a density sensor which receives a developer from a developer collecting fin from a paddle wheel. CONSTITUTION:The density sensor 15 is provided over the nearly center part of a screw agitator 16. The developer collecting fin 13 collects the developer enough to stay sufficiently in the hole 15a of the density sensor 15. When none of screw agitator 16, a lower scooping sleeve 5, and an upper scooping sleeve 6 is in operation and the developer does not circulates, the density sensor 15 detects the toner density of the developer in the hole 15a, and this detection is carried out under no influence of the rotation of the paddle wheel 4 because of the isolating function of a developer receiving plate 17 as to the paddle wheel 4, so the toner density of the developer in the hole 15a is detected accurately and stably. Namely, the detection frequency of the density sensor is stabilized. |
