| 摘要 |
PURPOSE:To easily find control abnormality of an exposure lamp by providing a circuit which detects the detection level of a light quantity sensor and a means which decides on the decision value of the circuit. CONSTITUTION:The detection output of the light quantity sensor 3 which detects the illuminance of the exposure lamp for forming an image on a photosensitive body is inputted to an automatic exposure controller 8 and comparators 10-12, and the controller 8 controls the exposure lamp to hold the quantity of light to the photosensitive body constant. The comparator 10 is set to detected electric power when the exposure lamp emits light with an upper-limit output, the comparator 11 is set to a mean output, and the comparator 12 is set to a lower-limit output. It is decided that the exposure lamp illuminates abnormally unless decision values of the comparators 10-12 are at normal level. |
