| 摘要 |
<p>BF/AN 6943 DOCUMENT SCANNER A scanner for scanning a document positioned against a backing surface to determine the position of the document includes photoelectric transducers which provide electrical scan signals in dependence upon the light reflected from the document and from the backing surface at a plurality of moving scan positions as the scan positions move across both the document and the backing surface. A recognizable background image is defined on the document backing surface such that the photoelectric transducers provide a recognizable pattern of scan signals as the document backing surface is scanned, thereby indicating the position of the document. The recognizable background pattern may include a plurality of stripes on the document backing surface with the stripes extending substantially parallel to the direction of movement of the scan positions. Alternatively, the recognizable background pattern may include a plurality of stripes which extend substantially perpendicular to the direction of movement of the scan positions. Alternate ones of the stripes may be black with intermediate ones of the stripes being white. A circuit means may be provided for detecting the recognizable pattern of the scan signals.</p> |
