| 摘要 |
PURPOSE:To simplify a controller for an exposure lamp which controls the exposure quantity of an original image to a constant value by providing a light shielding member which shields the light to a photodetector provided with an exposure area other than an exposure area where the exposure lamp is positioned. CONSTITUTION:One surface of an original which is conveyed by a 1st supporting cylinder 14 is irradiated with the light from the exposure lamp 16 at the irradiation position 19 of the exposure area 12. Reflected light from the original surface reaches a 1st photodetector 20 composed of a photodiode, etc., whose signal indicates the variable density of the original surface. The light shielding member 18 in such a shape that when the aliger 9 is in the exposure area 12, the direct light from the lamp 16 does not reach a 2nd photodetector 22 in an area 13 and reflected light from other members does not reach an element 22 is provided. The outputs of elements 20 and 22 are handled as independent outputs, so electric constitution which controls the light emission quantity of the exposure lamp is simplified. |
