摘要 |
In a document for sensing information, while the document to be sensed is fed in one direction, both surfaces of the document are illuminated by the respective sources of light. Light reflected by one and then the other surface of the document alternately reach a one-dimensional image pickup element. The light sources may be turned on and off. Alternately, the sources of light may be left on, in which case light reflected by both surfaces of the subject are intermittently interrupted.
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