| 摘要 |
PURPOSE:To surely carry out toner concentration control at a high precision by detecting toner concentration by reading output during developing from a concentration detection sensor and an environmental temperature detection sensor and controlling toner replenishing based on this. CONSTITUTION:The toner concentration detection sensor 24 is provided in an appropriate position in a developing device 15, preferably in a circulatory path of the developer, and especially in a path 26 where the developer cut of by a bristle cutting mechanism 22 is returned from the ear cutting mechanism 22 to an agitator 16. Furthermore, the detection sensor 25 of the environmental temperature, etc., is provided in a position outside the developing device is but in the closest possible vicinity to this. Then, electrical output from the toner concentration detection sensor 24 and electrical output from the environmental detection sensor 25 are fed to a central processing unit (CPU) 27, calculated, and ON-OFF control of a toner replenishing roll 19 is carried out according to this calculated result. Thus, the toner concentration control of high precision and which is appropriate for the actual developing condition can be carried out. |
