| 摘要 |
PURPOSE:To control the light quantity of a light source in accordance with the light receiving quantity of a photodetector, by installing a filter having transmittivity corresponding to the sensitivity of a photosensitive body integrally with a cartridge between the light source and the photodetector. CONSTITUTION:A cartridge guide 8 provided on a device body 9 is opened and closed from the device body so that a cartridge can be attached and detached, or a jam processing can be executed. As for a light guide 2, an optical fiber is suitable, but anything that guides a light beam may be suffice, and as for a photodetector 4, a photodiode such as a silicon photodiode, etc., is suitable. A part of a light beam from a light source 1 passes through the light guide 2 and a filter 3, and made incident on the photodetector 4, so that a prescribed light quantity corresponding to the sensitivity of a photosensitive body can be maintained by a light control circuit 6 receiving the output signal of the photodetector 4, based on its input quantity. Such a constitution is not loaded on the side of the light control circuit 6 and a cartridge 7, therefore, a contact becomes unnecessary, and it is effective for the device of a cartridge type.
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