| 摘要 |
PURPOSE:To form a distinct image without being affected by the classification of an original picture by controlling a bias supply means in accordance with the classification of the original picture and changing the DC component of the developing bias voltage supplied to a developing means and the potential difference of an image carrier. CONSTITUTION:An operation panel 12 is connected to a control part 11, and this panel 12 is provided with a mode switching key 13 which designates the classification of the original and copying in the character mode. A developing bias power source 14 which generates the developing bias voltage is connected to the control part 11. This developing bias power source 14 can switch and generate the DC voltage in the developing bias voltage and the potential difference of a photosensitive drum in accordance with the command of the control part 11 by, for example, switching of a DC resistance, and this generated developing bias voltage is supplied to a developing roll 15. Thus, the DC component of the developing bias voltage supplied to the developing means and the potential difference of the image carrier are changed to form a distinct image without being affected by the classification of the original picture. |
