| 摘要 |
PURPOSE:To detect the concn. of a developer with high accuracy by connecting capacitive load to one of a pair of coils wound on a vessel which stores the developer and comparing the output currents of both coils. CONSTITUTION:A reactor 1 is constituted of a square cylinder 2 formed of an insulator such as a resin material, coils 3, 4 wound respectively to the cylinder 2, and an iron core 5 which serves also as a magnetic path and a shield and is stuck on the side surface of the cylinder 2 so as to ride across the coils 3, 4. When the amt. of the toner in the cylinder 2 decreases, the amt. of the carrier, for example, the amt. of iron powder, increases relatively; therefore, the magnetic resistance of the magnetic path by the iron powder decreases and the number of magnetic lines of force increases with respect to the magnetic fields generated by the currents flowing in the coils 3, 4. As a result, the reactances of the coils 3, 4 increase and the inflow currents decrease. Conversely, when the amt. of the toner increases, the inflow currents of the coils 3, 4 increase. Thus, phase differences are given to the currents flowing into the coils 3, 4 by means of a capacitor 11 and the current values flowing in both coils are compared, whereby the concn. of the developer is detected. |
