| 摘要 |
PURPOSE:To prevent the adhesion of toner and to accurately detect concentration by forming a detecting part of a material which has the electrostatically charged polarity same as that of the toner in a developer concentration detecting device for developer which is constituted of the toner having the specified triboelectric charging quantity and carrier. CONSTITUTION:The toner concentration is detected by a toner concentration detecting means 9 based on a difference between a voltage which is outputted after a sensor 9b directly receives the light of a light source 9a and the voltage which is outputted after a sensor 9c receives the light reflected on the developer through a detecting window 5b. By using the toner whose absolute value of the triboelectric charging quantity in the developing is 10 - 40 muc/g, and further more, by forming the detecting window 5b of the material having the electrostatically charged polarity same as that of the toner, the toner is prevented from adhering on the detecting window 5b. Thus, the toner can be prevented from adhering on the detecting window and the toner concentration can be accurately detected without the need of a special auxiliary mechanism. |
