| 摘要 |
PURPOSE:To make needless the manual operation by which the exposure quantity is adjusted according to originals, by reading the texture density of the original to adjust the exposure quantity in the electrohpotographic copying machine. CONSTITUTION:When print switch 21 is turned on, the signal from sensor 17 is converted to a voltage by voltage level converting circuit 28, and the maximum voltage is selected by operating circuit 29. This maximum voltage corresponds to the maximum incident quantity to sensor 17 and is stored in memory circuit 30 as the texture density of the original. Density detection control circuit 22 outputs a position signal according to this texture density, and this position signal is compared with the signal from position detecting circuit 31 in comparing part 32, and step motor 16 is driven according to the output. The rotation detection of step motor 16 is detected by position detecting circuit 31, and consequently, the opening angle of the stop of the copying machine is controlled according to the texture density of the original, and the exposure quantity is adjusted to an optimum light quantity according to the texture density of the original. |
