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HIGH SPEED LASER SCANNER

IP.com Disclosure Number: IPCOM000026148D
Original Publication Date: 1990-Aug-31
Included in the Prior Art Database: 2004-Apr-05
Document File: 2 page(s) / 95K

Publishing Venue

Xerox Disclosure Journal

Abstract

Laser scanning systems conventionally used a spinning polygon with associated optics to scan a beam onto a photosensitive image surface. Problems with this conventional arrangement include facet angle variability, reflectivity variations, motor wobble and motor vibrations, all of which contribute to pixel placement errors that cause flaws in the prints. The writing speed of printers is often limited by the cost of the polygon scanner. Beam shaping and steering optics also contribute to the cost of complexity of this scanner design. Simplifying the printer by removing the polygon scanner and polygon optics would lead to an improvement in cost, speed and performance. Such a simplified scanner is enabled by mounting a laser diode on the outer edge of a rotating disk with the diode positioned above the circle of optical fibers of a circle-to-line converter. This arrangement can be used to create a scanning spot of light without the need for a polygon. A circle-to-line converter is an arrangement of optical fibers that takes the points on a circle (the input fibers) to points on a line (the output fibers). The first and last fibers are adjacent to each other on the circle, but are at opposite ends of the line. The output fiber density of the line would be at the desired spot density (300 to 400 SPI), while the input fiber density of the circle would be greater. With this arrangement, the laser would always overfill the input fiber so the scanner is less sensitive to motor vibrations and wobble. Because the scanner contains fewer parts, cost should be lower while alignment will be easier.

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XEROX DISCLOSURE JOURNAL

HIGH SPEED LASER SCANNER

Proposed Thomas J. Hammond U.S. C1.355/008 Classification

Int. C1. G03g 15/28

Laser scanning systems conventionally used a spinning polygon with associated optics to scan a beam onto a photosensitive image surface. Problems with this conventional arrangement include facet angle variability, reflectivity variations, motor wobble and motor vibrations, all of which contribute to pixel placement errors that cause flaws in the prints. The writing speed of printers is often limited by the cost of the polygon scanner. Beam shaping and steering optics also contribute to the cost of complexity of this scanner design. Simplifying the printer by removing the polygon scanner and polygon optics would lead to an improvement in cost, speed and performance. Such a simplified scanner is enabled by mounting a laser diode on the outer edge of a rotating disk with the diode positioned above the circle of optical fibers of a circle-to-line converter. This arrangement can be used to create a scanning spot of light without the need for a polygon. A circle-to-line converter is an arrangement of optical fibers that takes the points on a circle (the input fibers) to points on a line (the output fibers). The first and last fibers are adjacent to each other on the circle, but are at opposite ends of the line. The output fiber density of the line would be at the desired spot density (300 to 400 SPI), while the input fiber density of the circle would be greater. With this arrangement, the laser...