| 摘要 |
PURPOSE:To automatically compensate developing bias without being influenced by noise by providing a control means which decides ON/OFF ratio of a switching means according to a deviation of maximum voltage of a signal converting means and a reference voltage set beforehand. CONSTITUTION:This device is provided with a detection means 501 which optically reads ground density of an original paper and converts it to an electronic signal, the switching means 503 which switches a detection signal by the detection means 501, a signal conversion means 504 which makes the switched signal DC, and a control means 507 which decides the ON/OFF ratio of the switching means 503 according to the deviation of the maximum voltage of the signal conversion means and the reference voltage set beforehand. Then, the switching processing is carried out according to the difference between the detected value of the ground density and the reference value set beforehand, the voltage by this switching becomes the developing bias, and correction is carried out sequentially by the ground density detection value. Thus, correction of the developing bias can be carried out automatically without being influenced by the noise. |
