| 摘要 |
PURPOSE:To make it possible to maintain the most suitable concn. of a toner at all times and to control the concn. with high reliability, by controlling the feed quantity of a toner in accordance with movement of a developer in an electrophotographic copying machine. CONSTITUTION:Oscillation frequency of the oscillator 20 is varied in accordance with a variation of the inductance value of a detecting coil 14, by providing a bobbin 13 on the moving passage of a developer 4, and winding to the bobbin 13 the detecting coil 14 whose inductance value varies in accordance with the developer 4 passing through the bobbin 13. Also, each output of each oscillator 20, 26 is divided by the frequency dividers 25, 32, respectively by providing the oscillator 26 which generates a reference signal of regular frequency, the frequency divider of the other side is cleared mutually by each frequency division output, and a toner 11 is replenished into the developer in accordance with the output of each frequency divider. Accordingly, a toner is replenished swiftly and exactly in accordance with a variation of the concn. of a toner, and the concn. of a toner can be maintained at the most suitable value at all times. |
