| 摘要 |
PURPOSE:To obtain an invariably stable reproduced picture regardless of an orig inal by measuring original density by a preliminary scanning system and a sequential comparison system, and controlling the amount of original exposure by the sequential comparison system when it is judged by the preliminary scanning system that the set amount of exposure is improper. CONSTITUTION:The control value VAC of an original illumination lamp 108 corresponding to an original density measured value VAE obtained by a preliminary scan is outputted to turn on the lamp 108. Then, paper feeding is started and an optical system starts moving forth to wait for the inversion position of the optical system. An AE circuit 122 monitors the output of an original sensor 116 during said period, and when the optical system arrives at a cutting part, a value larger than VAE is obtained. When this state is held continuously for a specific time or longer, a VAE table TBL is drawn with a new value obtained by the original sensor 116 instead of the value VAE obtained by the preliminary scan, and the value obtained mentioned above is outputted as VAC. Thus, a comparison is made successively to control the turn-on voltage of the original illumination lamp 108. |
