JPS5462833A - Controlling method of original exposure - Google Patents

Abstract

PURPOSE:To achieve the automation of optimum exposure without impairing the performance of the copying apparatus by detecting the density of the original on the original base during the time when the original base or optical means reaches the exposure start position from the start position and controlling the exposure with the detection signal. CONSTITUTION:One or more photo detectors 25 are provided in opposition to an original lighting lamp 4 and the original is lighted by the lamp 4 during the time when an original base 3 moves from the start position in the A direction. The reflected light thereof is then received in the detectors 25. According to the original densities having been measured and detected with the detectors 25, the quantity of the light of the exposure performed while the original base 3 is moving in the arrow B direction is controlled. This is accomplished by, e.g., changing the voltage being applied to the lamp 4 with the detection signal by the detectors 25 thereby adjusting the quantity of light or adjusting the opening area of the slit or aperture in the optical path between the original and the photoreceptor. Since the measurement of the original densities has been completed before the start of exposure, copying production through automatic optimum exposure may be accomplished.