| 摘要 |
PROBLEM TO BE SOLVED: To detect discharge with simple constitution by using a discharge detection electrode, a power source, an ammeter and a microcomputer. SOLUTION: By installing the discharge detection electrodes 61a and 61b near a developing sleeve 5 in a developing device, developer 67 being a discharge detection object enters between the electrodes 61a and 61b. Voltage nearly equal to applied developing bias is applied to the power source 63. A current flowing in a discharge detection judging means 62 when the developer 67 enters between the electrodes 61a and 61b is measured by the ammeter 64. When the obtained current value exceeds a set threshold, the microcomputer 65 judges it as the discharge. In such a case, when the volume resistivity of the developer 67 between the electrodes 61a and 61b is lowered, the discharge occurs between the electrodes 61a and 61b. It is desirable to install the electrodes 61a and 61b at the position of a developer bank at the rear of a developing doctor 66 so that the developer 67 may easily enter between the electrodes. |
