| 摘要 |
PURPOSE:To prevent the occurrence of the toner concentration difference in an image, by inhibiting the developing operation when the output difference between plural toner sensors arranged in the axial direction of a developing roll exceeds a certain value, and releasing this inhibition when said difference is smaller than the certain value after agitation for a certain time. CONSTITUTION:If the output difference between toner concentration sensors 7a and 7b arranged in the axial direction of a developing roll 5 exceeds the certain value, it is judged that the toner concentration in a developing tank is not uniform in the axial direction of the developing roll 5. When this state continues over a certain time, a development impossibility flag is set to set the state where the developing operation is impossible. A developer is agitated by the developing roll 5 and an agitating roll 6; and after it is agitated until the output difference between sensors 7a and 7b is smaller than the prescribed value, the flag is reset to set the state where the developing operation is possible, and the interruption state is released. |
