| 摘要 |
PURPOSE:To easily and exactly execute an image density adjustment in case of manual operation, by adjusting manually the image density within a range which has conformed with a variable density state of an original. CONSTITUTION:When a manual setting circuit 11 has been set to a position in a thicker or thinner direction than an automatic exposure position, the gain adjusted by a gain adjusting circuit is changed by the manual setting circuit 11. Therefore, from the output adjusting circuit 12 which has received an output signal of an automatic exposing circuit 8, an amplifying signal whose level has been adjusted so as to correspond to an adjusted portion of the manual setting circuit 11 is sent out to a differential amplifier 4. For instance, when it has been detected by the automatic exposing circuit 8 that an original is short of light quantity by about 20%, an operator decides that a copy state is still dark by about 10%, and an amplification factor of the gain adjusting circuit 12 is raised by 10% by the manual setting circuit 11. As a result, a reference voltage which has been increased by a light quantity shortage portion of 30% is applied to the differential amplifier 4, and in accordance with said voltage, the exposure light quantity of an exposing lamp 1 is raised by 30%. |
