| 摘要 |
PROBLEM TO BE SOLVED: To successively detect the residual quantity of developer in a developer container and improve the convenience by equipping a measuring electrode member arranged in a section held in contact with the developer and a reference electrode member arranged in the section being free from coming into contact with the developer. SOLUTION: The measuring electrode member 20A is arranged in a position held in contact with the developer, such as an inside surface or the bottom surface in the developer container 11A of developing means 9, so that the area held in contact with the developer varies with the decrease of the developer. Then, the reference electrode member 20B is disposed in the developer container in the section divided by a partition wall that is free from coming into contact with the developer. The capacitance of the reference electrode member 20B changes in accordance with environmental conditions such as temp., humidity or the like and to function as a comparison member for referring to the measuring electrode member 20A. Namely, the output of the measuring electrode member 20A is compared with the output of the reference electrode member 20B flactuating with the change of environments. Thus, the output of only change portion of the capacitance by the developer can be obtained. |
