| 摘要 |
PURPOSE:To easily obtain an integrated circuit, by executing a control of a color temperature compensation circuit against a variation of a color temperature of a copying body, by means of a digital control. CONSTITUTION:The first, second and third color optical signals are inputted from terminals 21, 22 and 23. When an electric power source 60 is connected, a clock signal from a clock terminal 50 is inputted to an up-down counter 54. When a signal from the terminal 22 among the color optical signals is larger, and output of a differential amplifier 24 becomes a high level, and the up-down counter 54 is counted up by an increment portion of the signal. A counted-up digital signal controls an analog switching circuit 56 through a buffer amplifier 55, and decreases the degree of amplification of a color signal amplifier 4. In this way, the color temperature compensation against a color temperature of a copying body is digitally controlled completely, therefore, this compensation circuit is integrated easily. |
