| 摘要 |
PROBLEM TO BE SOLVED: To prevent dielectric breakdown of a photoreceptor when a high voltage is applied and to optimize the prevention of sticking of toner to a separation claw, by controlling, according to the result of the calculation of image density in the direction of the periphery of the photoreceptor, the value of a voltage applied to the separation claw. SOLUTION: 10-100 pixels of image data near a separation claw 170 in a main scanning direction are stored for each line into an FIFO memory, and the sum of movements of fixed lengths in a sub-scanning direction is calculated. The sum of the movements is converted into analog at real time by a D/A converter, and a CPU controls a DC bias value, an AC amplitude and duty in a separation claw high voltage generation circuit according to the an analog value read at an analog port. In the case the value of the addition in an adding circuit is small, it indicates toner is less in a part where the separation claw 170 abuts on a photoreceptor drum 110. Therefore, an output voltage peak value in an AC high voltage part is decreased. In the case a value added in the adding circuit is high, the output voltage peak value in the AC high voltage part is, on the contrary, increased. |
