| 摘要 |
<p>A scanner for scanning a beam across a surface, such as a photosensitive surface or a document, the scanner comprising: a plurality of multi-faceted polygon disks, mounted for common rotation on an axis; a plurality of data modulated beams, wherein one of said beams is configured to impinge on the facets of one of the disks and be reflected therefrom toward the surface. The plurality of polygon disks (26) are mounted with an angular shift between them and the beams from different polygon disks can be overlapped by a polarizer (42) on the surface after passing through an f-theta lens system (43). The beams scan the surface alternately, thereby increasing the duty cycle and scanning speed. Means for differentially varying the focussing in the scan direction (53, 55) and offset at the beams in the cross-scan direction (49, 51) are also provided. A polarising beamsplitter (39) may be used to produce the plurality of beams.</p> |
