| 摘要 |
PURPOSE:To detect conditions of the dirt of a photoelectric transducer, a rod lens, or the like, flaws of a photosensitive drum, etc. by comparing the output of the photoelectric transducer, which is closed together with a light emitting element array, with the output of the photoelectric transducer which is not closed. CONSTITUTION:The irradiating light of an LED array 5a is irradiated to a photosensitive drum 9 through a rod lens 5b, and a leaked light L which is not irradiated there is received by a photoelectric transducer 5d and is fed back to a control circuit 6 as an electric signal. Since the transducer 5d is shut out from the outside by a shielding cover 14 at this time, adjustment and control are so performed that the array 5a generates the stable quantity of light. Meanwhile, the light passing through the lens 5b is reflected on the drum 9 and is inputted to a photoelectric transducer 5c and is converted to an electric signal and is outputted. This output signal is compared with the output of the transducer 5d by a comparing circuit 7, and a display device 8 is operated in accordance with the comparison result. |
