| 摘要 |
PURPOSE:To stabilize the flow of a developer and to detect the concentration of toner with high precision by providing a conveyance plate opposite a detection head, providing a projection to the conveyance plate, and extending the projection to the flow passage of the developer which consists of the detection head and conveyance plate. CONSTITUTION:A latent image on a photosensitive drum 7 is developed by conveying the developer to a developing roller 34. At this time, the remaining developer is returned through a developing chamber 32 by the rotation of the developing roller 34. Further, a toner concentration detecting device 40 is provided to the developing chamber 32 and a detection coil 41 is covered with the detection head 42a. Further, the conveyance plate 38 is provided in opposition to it to form the flow passage 43 of the developer. This conveyance plate 38 is provided with the projection 44 to stabilize the flow state of the developer, thereby detecting the toner concentration from variation in the inductance of the detection coil 41. Thus, the projection is extended to the flow passage of the developer to stabilize the flow at the peripheral part of the detection part, so the toner concentration is detected with high precision. |
