| 摘要 |
PURPOSE:To obtain a stable sensor without the effect of change in environment such as temperature by providing a pair of oscillating coils around one magnetic core, and arranging one coils in the vicinity of toner in a containing body. CONSTITUTION:One magnetic core has a shape wherein two E-shaped magnetic cores are bonded. An oscillating coil L1 around which a winding W1 is wound is made to be a first oscillating circuit 1. An oscillating coil L2 around which a winding W2 is wound by the same way constitutes a second oscillating circuit 2. One coil L1 is arranged in the vicinity of developing powder 13 in a containing body 12. When a developing agent comprising one component is used, the inductance of the coil L1 is increased or decreased in correspondence with the remaining amount of toner. The phases of the outputs of both oscillating circuits 1 and 2 are changed. The changes are detected with a phase detecting circuit 3. When developing agent comprising two components is used, the toner is decreased and iron powder is increased. Then the inductance is increased and can be detected. The temperature changes in both coils become the same conditions. |
