29 December 1993 Dual-beam modulation subsystem for high-speed digital copier
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The Xerox Docutech High-Speed Digital Copier achieves an output print speed of 135 (14 in X 8.5 in) pages/minute, at 600 dots/ inch resolution. Its digital optical image is generated by a laser scanner whose dual-channel modulation subsystem (AOM/D) enables this performance capability through crystal beam splitting/recombination optics, polygon facet tracking, pulse-imaging, and a dual-electrode Bragg cell. The AOM/D features: 86% throughput enabling the use of a standard 5 mW package size 633 nm Helium-Neon laser. Facet-tracking, enabling the use of a 63.5 mm diameter 18-facet polygon rotating at 22 KRPM. The splitting optics generate two cross-polarized beams which are then modulated independently by the dual-channel Bragg cell. The recombination optics enable tight separation control between the two adjacent scan line spots at the photoreceptor with excellent stability. Symmetrization of path lengths insures that the scan and cross-scan waists and image structures are imaged at the same plane. The Bragg cell and associated driving electronics accommodate modulation of 66 Mbits/sec per channel and >= 20:1 contrast ratio of pulse-imaged pixels. Design and manufacturing aspects are discussed.
© (1993) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jean-Michel Guerin, "Dual-beam modulation subsystem for high-speed digital copier", Proc. SPIE 1987, Recording Systems: High-Resolution Cameras and Recording Devices and Laser Scanning and Recording Systems, (29 December 1993); doi: 10.1117/12.165211; https://doi.org/10.1117/12.165211

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