| 摘要 |
PURPOSE:To always read films with a proper light quantity by exposing an area of a film where no image is recorded with a light source and controlling the light quantity of the light source based on the output of a photoelectric converting means produced by the transmitted light quantity. CONSTITUTION:The count value of an up-counter 36 is converted through a D/A converting part 37 to increase the electric power supplied to a lamp 24. Thus the light quantity is gradually increased to produce an overflow. Here a flip-flop 34 is reset to stop the generation of clocks of a clock generator 35. Thus the counter value of the counter 36 is held together with the output of the part 37. Then the light quantity is fixed. While a control part 41 decides the end of the setting of light quantity by an overflow signal and starts an image reading action. In this case, a motor 42 is driven again to advance a microfilm by a prescribed amount. Then a desired frame is set at a position where an image sensor 27 can read the frame. The microfilm is exposed with a set light quantity and the sensor 27 reads images.
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