| 摘要 |
PURPOSE:To prevent the influence caused by the fluctuation of the light quantity of a lamp to the output of an image information signal and to detect the fault of the lamp and to give alarm by detecting the light quantity of a lamp being a light source for lighting an original and controlling the output of a photoelectric transducer. CONSTITUTION:The light quantity measured and detected by an LS circuit, that is the output of an operational amplifier 109 is A/D converted by an A/D converter 110 and transmitted to a control part 101 as a digital information signal. If the digital information signal is lower than the prescribed level, a driving signal is transmitted to an alarm display part 111. If higher, the output is operated together with pre-set information and an image sensor driving control signal is supplied to a driver 106. As the light quantity detection circuit LS can obtain the output in linear proportion to the light quantity of the lamp being a light source, the output of the operational amplifier 109 becomes double, where the light quantity of the lamp becomes double. Therefore the control part 101 sets the image accumulation period T of a charged leftclock signal phiSH to 1/2 in inverse proportion to the light transmission quantity of an film original. Thus the image information signal obtained from a line image sensor 11 always becomes an output signal at the prescribed level.
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