| 摘要 |
PURPOSE:To automatically control copying density by controlling developing bias voltage in accordance with the detected conditions of an original to set it to a proper value. CONSTITUTION:An original 1 is conveyed one by one with a paper feed belt 4, and fed through a guide plate 6 onto a platen glass 7 with a conveying roll 5. The original 1 is scanned with light from a light emitting lamp 9 and the reflected light falls on a photodetector 10 while it is conveyed. Its output is fed through an amplifier 11 to a comparator 12 to compare with a predetermined voltage, and developing bias voltage is set to a proper value in the range from the min. potential ( I ) to the max. potential (III) through drivers ( I , II, III) 13- 15 in accordance with its output signal to control copying density with high precision. |
