Single sensor laser beam synchronizer and intensity regulator
AssigneeXerox Corporation
InventorFrank C. Genovese
Life of this patent
Estimating the term…
Abstract
A raster output scanner in which both the start-of-scan and the beam intensity of a laser beam are determined using a single photodetector. The raster output scanner has a laser source for generating a laser beam; a rotating polygon for sweeping the laser beam along a scan line plane, an optical fiber with a light receiving end positioned at a known position in the scan line plane and which intercepts at least a portion of the sweeping laser beam, and a photodetector for converting the intercepted laser beam into a beam current. The raster output scanner further includes both a scan detection circuit for producing a star-of-scan signal from the beam current and a beam intensity circuit for producing an electrical output which depends upon the magnitude of the beam current.
Claims9
A raster output scanner, comprising:
- a laser source for generating a laser beam having an intensity that is dependent upon a beam control signal;
- a rotating polygon for sweeping the laser beam along a scan line plane;
- an optical fiber with a light receiving end and a light exit end, wherein said light receiving end is positioned in the scan line plane so as to intercept at least a portion of the sweeping laser beam;
- a photodetector for converting the intercepted laser beam that leaves said exit end into a beam current which depends upon said laser beam intensity;
- a scan detection circuit for producing a start-of-scan signal from said beam current;
- and
- a beam intensity circuit for producing said beam control signal from said beam current.
A printer comprised of:
- a photoreceptor having a photoconductive surface which moves in a process direction;
- a charging station for charging said photoconductive surface to a predetermined potential;
- a raster scanner assembly for exposing said photoconductive surface to produce a first electrostatic latent image on said photoconductive surface by sweeping a modulated laser beam across said photoreceptor in a fast scan direction which is substantially perpendicular to said process direction;
- a first developing station for depositing developing material on said first electrostatic latent image so as to produce a first toner image on said photoconductive surface;
- a transfer station for receiving said first toner image from said photoconductive surface and for transferring said first toner image onto a substrate;
- wherein said raster scanner assembly includes:
- a laser source for generating a laser beam having an intensity that is dependent upon a beam control signal;
- a rotating polygon for sweeping the laser beam along a scan line plane;
- an optical fiber with a light receiving end and a light exit end, wherein said light receiving end is positioned in the scan line plane so as to intercept at least a portion of the sweeping laser beam;
- a photodetector for converting the intercepted laser beam that leaves said exit end into a beam current which depends upon said laser beam intensity;
- a scan detection circuit for producing a start-of-scan signal from said beam current;
- and
- a beam intensity circuit for producing said beam control signal from said beam current.
Dependencies are inferred from the claim text.