| 摘要 |
PURPOSE:To surely detect the consumption of a developer even if it is locally consumed by arranging two detecting conductors while opposing to a developer carrier. CONSTITUTION:The detecting conductors 3a and 3b are arranged while opposing to a developing sleeve 1, and a change in the quantity of toner 4 is detected as a voltage. The detected direct current voltages VDC1 and VDC2 are supplied to corresponding comparatiors 9a and 9b, respectively, and compared with constant direct current voltages VS1 and Vs2 from reference voltage sources 8a and 8b. When the toner 4 is unequally consumed, the output from the comparators 9a and 9b is inverted, a toner bias display circuit 11 is operated through an OR circuit 10, and the bias of the toner is informed outside. Thus, even if the developer 4 is unequally consumed, the fact can be surely detected. |
