| 摘要 |
PURPOSE:To form efficiently an excellent copy image whose density is controlled by sampling and detecting the light and shade of an original plural time from the front end of an original, judging the light and shade, and performing optimum control. CONSTITUTION:A reflected light detection output of a photodiode 1 for reflected light from the original is inputted to a microcomputer 7 to perform interruption processing. This interruption processing is carried out according to a program based upon the zero-cross signal of an AC power source which is passed through an operational amplifier 11 and a transistor 12, and the light and shade of the original is sampled and detected plural times from the front end of the original to judge the light and shade of the original by the computer 7, optimizing the DC component of a development bias voltage through a high-voltage transformer 8. Consequently, an excellent copy image whose light and shade is controlled according to the original surface is formed efficiently without any miscopying, etc. |
