| 摘要 |
PROBLEM TO BE SOLVED: To improve image quality and to form an image high in reliability by facilitating the correction of density difference in read images. SOLUTION: An AGC-M0 circuit 130 connected to an output terminal OS1 in a quadripartite photoelectric transducer (CCD) 34 divided lets a constant current flow through a differential amplifier circuit 131 by using the differential amplifier circuit 131, a both terminal detection circuit 132, a differential amplifier circuit 133, a comparator circuit 134, a control reference value 135, a constant current circuit 136 and a voltage holding circuit 137 to output the compared result of the comparator circuit 134 as a control reference value for AGC-S1 circuit 140 to AGC-S3 circuit 160, thus the density difference is corrected at the AGC-S1 circuit 140 connected to an output terminal OS2, AGC-S2 circuit 150 connected to an output terminal OS3, and AGC-S3 circuit 160 connected to an output terminal OS4. |
