| 摘要 |
PURPOSE:To always minimize the stirring of a developer and to prevent the scattering of toner, fog development and the degradation of the developer by varying the rotational speed of a stirring member stirring the replenished toner and the developer. CONSTITUTION:A density sensor 10 is arranged in proximity to the central part in the axial direction of a photoreceptor and detects the density of the visual image of a reference density pattern formed on the nonimage part of the photoreceptor. A control part 9 detects the toner concentration of the developer from the output voltage of the density sensor 10 and when the output voltage is not a voltage corresponding to the optimum toner concn. of the developer, executes control to keep the toner concn. of the developer constant in such a manner that a replenishing roller driving motor 4C4 is rotated via a driver for driving 13 and the toner is replenished from a replenishing tank. Moreover, the control part 9 controls a paddle driving motor 4B1 via a driver for driving 12, in accordance with the output voltage of the density sensor 10 with respect to the density of the visual image of the reference density pattern, to control the rotational speed of a paddle wheel stirring the replenished toner and the developer. |
