Browse Prior Art Database

Double-Beam Electrophotographic Laser Printer/Scanner

IP.com Disclosure Number: IPCOM000043924D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Imaino, WI: AUTHOR

Abstract

An electrophotographic printer/scanner system is shown and described in which dual beams are formed which are angularly separated so that, by summing the two printer/scanner signals, a better signal/noise ratio or dynamic range of a laser printer/ scanner is achieved. The system includes a photoconductor drum 10 upon which is formed a toned image by conventional techniques. A scanning beam 11 is projected along a path including a half-silvered mirror 12 which forms two separate beams 13 and 14. Beams 13 and 14 are each directed by mirrors 15, 16 and 17 over a path to photoconductor drum 10 to scan the image thereon. The scattered radiation from each of the beams is directed by a Fresnel lens 18 to a sensing photodiode 19.

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Double-Beam Electrophotographic Laser Printer/Scanner

An electrophotographic printer/scanner system is shown and described in which dual beams are formed which are angularly separated so that, by summing the two printer/scanner signals, a better signal/noise ratio or dynamic range of a laser printer/ scanner is achieved. The system includes a photoconductor drum 10 upon which is formed a toned image by conventional techniques. A scanning beam 11 is projected along a path including a half-silvered mirror 12 which forms two separate beams 13 and 14. Beams 13 and 14 are each directed by mirrors 15, 16 and 17 over a path to photoconductor drum 10 to scan the image thereon. The scattered radiation from each of the beams is directed by a Fresnel lens 18 to a sensing photodiode 19. The two beams must have equal path lengths so that the scan spots coincide along each portion of the scan. In addition, the angles of incidence of the two beams must differ by a fixed amount so that the variations in the scattered signals are minimized. The signals represent the reflected light intensity versus spatial intensity of the spot for the two beams. It is apparent that the system which utilizes two beams results in significantly less noise when compared to systems which use single beams. A similar result can be predicted for the printing function. Thus, this system demonstrates a method for improving the signal/noise ratio or dynamic range of a laser printer/scanner by reducing the...