| 摘要 |
PURPOSE:To know the dirty degree of an optical system and to correct the quantity of light, by comparing the output of a detector for the light of an exposure lamp with a reference value. CONSTITUTION:While a microfilm 2 is not set, a controller 13 receives a digital light-quantity signal from a photosensor 6 through an amplifying and converting circuit 10 to calculate the difference from the reference amount of exposure, thereby storing variation in the quantity of light of a light source due to the dirty state in the machine and the replacement, etc., of a lamp 1. Then while the film 2 is set, the controller 13 receives a digital light-quantity signal from a photosensor 7 through the circuit 10 to calculate the difference from the stored digital light-quantity signal, thus finding the density of transmitted light of the film 2. Then, the controller 13 outputs the voltage of the lamp 1 for the adequate amount of exposure to a lamp voltage controlling circuit 11 on the basis of variation in the quantity of the light source, the density of transmitted light of the film 2, and data from a magnification setter 12. |
