| 摘要 |
PURPOSE:To provide a toner concn. detecting device capable of always performing the accurate toner concn. detection stably, even if the toner concn. sensor is soiled by the toner scattering and so on. CONSTITUTION:The detection probe 21 provided with the toner non-sticking face 21a and the toner sticking face 21b is fixed on the same shaft in the end part of the photoreceptor drum 17. The toner concn. sensor 41 is made possible to move on the detection probe 21 by the on/off of the plunger solenoid 45. Then, the state of soiling due to the toner scattering, etc., is confirmed by periodically moving the toner concn. sensor 41 to the toner non sticking face 21a of the detection probe 21 and detecting the reflected light quantity there. Moreover, based on the state of soiling, the message is displayed on the panel to the effect that the toner concn. sensor 41 should be cleaned when the soiling is heavy, and when the soiling is not heavy, the correction is made with regard to the toner target value of the toner sticking face 21b corresponding to the state of the soiling. |
