| 摘要 |
PROBLEM TO BE SOLVED: To prevent the blockage of miniaturization by projecting a sensor for detecting the concn. of toner, at the time of attaching the sensor from the outside of a developing tank. SOLUTION: In a developing device 8 having a developing roller 21 for carrying a developer to a position facing a photoreceptor 4, the developing roller 21 is provided in the developing tank 20 housing the developer consisting of the toner and carriers and a stirring roller 22 for stirring/mixing the supplied toner with the developer is provided on a side opposite to the photoreceptor 4. A toner concentration sensor 29 is provided in the developing roller 21 facing the part of the stirring roller 22, that is, a magnet 21b inside a developing sleeve 21a, so that the detecting surface 29a of the sensor 29 faces the developing sleeve 21a. Thus, the concn. of the toner of the developer attracted to the sleeve 21a is detected by the toner concentration sensor 29 inside and toner supplying control is executed by a toner supplying device 18, in accordance with the result of the detection. |
