| 摘要 |
PURPOSE:To measure the transmittance of an original always accurately by reading the transmittance of the original in correspondence to the conveyance speed of the original in an average manner. CONSTITUTION:An original O is read of its transmittance by an original transmittance detector consisting of a light source 1 and a photodetector 2, and the data thereof are A/D-converted and are introduced into a microcomputer. At the same time, a photointerruptor 5 consisting of a disc provided with multiple holes is provided on a driving roll which drives a conveyance belt 3, and the pulses generated by this are put into the interruption terminal of the microcomputer, by which interruption is generated at every pulse. The output processed by the microcomputer are D/A-converted and control a motor for conveyance or a light source for exposure by way of a control circuit. In this way, the transmittance of the original is read in an average manner with respect to the conveyance speed of the original, and based on these data, the motor or the light source for exposure is controlled and therefore correct exposure is obtained. |
