Method and apparatus for beam displacement in a light beam scanner
First Claim
Patent Images
1. A method for light beam scanning of a scan receiving member, comprising the steps of:
- generating a light beam;
admitting a portion of the light beam and blocking the remainder of the light beam so as to form an admitted light beam;
deflecting the admitted light beam so as to effect plural line scanning of the scan receiving member;
providing spacing between sequential scan lines;
determining potential scan line spacing error; and
controlling the admitted light beam portion in accordance with the potential scan line spacing error so as to displace the admitted light beam to compensate for such error.
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Accused Products
Abstract
A method and apparatus is provided for line scanning a beam receiving member, wherein a scanning beam is angularly or laterally displaced to compensate for potential scan line spacing error. The beam is displaced according to error arising from variation (flutter) in the relative motion of the beam and the beam receiving member, or according to error arising from movement of the receiving member while the scanning beam travels to a start of scan position, or both. Embodiments of beam displacement means include a row-addressable light valve array and an area-addressable light valve array.
14 Citations
22 Claims
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1. A method for light beam scanning of a scan receiving member, comprising the steps of:
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generating a light beam; admitting a portion of the light beam and blocking the remainder of the light beam so as to form an admitted light beam; deflecting the admitted light beam so as to effect plural line scanning of the scan receiving member; providing spacing between sequential scan lines; determining potential scan line spacing error; and controlling the admitted light beam portion in accordance with the potential scan line spacing error so as to displace the admitted light beam to compensate for such error. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for light beam scanning exposure of a photosensitive medium, comprising the steps of:
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generating a laser beam; admitting a portion of the laser beam and blocking the remainder of the laser beam so as to form an admitted beam; deflecting the admitted beam so as to effect repeated line scans of the photosensitive medium; selectably modulating the laser beam to effect plural line scan exposures of the photosensitive medium; providing relative motion in the cross-scan direction between the photosensitive medium and the admitted beam to effect spacing between sequential scan line exposures, the spacing being subject to error; determining potential scan line spacing error; generating an error correction signal; and controlling the admitted light beam portion in accordance with the error correction signal so as to displace the admitted beam to compensate for such error. - View Dependent Claims (11)
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12. Apparatus for scanning a light beam on a scan receiving member, comprising:
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means for generating a light beam; means for admitting and blocking first and second portions, respectively, of the light beam so as to form an admitted beam; means for deflecting the admitted light beam so as to effect plural line scanning of the scan receiving member; means for providing spacing between sequential scan lines; means for determining potential scan line spacing error; and means for controlling the light beam admission in accordance with the determination of the potential scan line spacing error so as to displace the admitted light beam to compensate for such error. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. Apparatus for light beam scanning exposure of a photosensitive medium, comprising:
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means for generating a laser beam; means for admitting a portion of the laser beam and blocking the remainder of the laser beam so as to form an admitted beam; means for deflecting the admitted beam so as to effect repeated line scans of the photosensitive medium; means for selectably modulating the laser beam to effect plural line scan exposures of the photosensitive medium; means for providing relative motion in the cross-scan direction between the photosensitive medium and the admitted beam to effect spacing between sequential scan line exposures, the spacing being subject to error; means for determining the error in the spacing; means for generating an error correction signal; and means for controlling the admitted light beam portion in accordance with the error correction signal so as to displace the admitted beam to compensate for such error. - View Dependent Claims (22)
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Specification