Photocopying – Contact printing – Light boxes
Patent
1990-12-12
1992-01-14
Grimley, A. T.
Photocopying
Contact printing
Light boxes
355214, 355228, G03G 2100
Patent
active
050814923
ABSTRACT:
An exposure control system for a document copier is enabled by positioning a segmented variable reflectance mirror along the optical imaging path. The mirror segments incorporate a material whose transmission changes in response to applied voltage signals, the preferred material being an electrochromic material. In a first embodiment a white reference strip along the platen surface is exposed and the charge levels along discrete areas of the photoreceptor are measured by an electrometer with a plurality of probe segments. Outputs from each probe segment are processed in a control circuit and a signal sent to an appropriate mirror segment to increase or decrease reflectance to enable a corresponding decrease or increase, respectively, of the charge level, at the corresponding discrete areas of the photoreceptor illuminated by the mirror segments.
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High Technology Magazine, p. 7, Published Jul. 1987 "Auto Mirrors Dim the Glare".
Grimley A. T.
Lee Shuk Y.
Xerox Corporation
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