Browse Prior Art Database

SELF-REFERENCING PHOTORECEPTOR POSITION SENSOR

IP.com Disclosure Number: IPCOM000027007D
Original Publication Date: 1994-Dec-31
Included in the Prior Art Database: 2004-Apr-07
Document File: 4 page(s) / 145K

Publishing Venue

Xerox Disclosure Journal

Abstract

A belt marker position sensor is described which has the capability of detecting its own location relative to an actual scan line. The sensor makes this possible by using detectors to locate the optical axis of the scan line relative to the belt hole sensing position and eliminates the need to precisely position the sensor on a production line.

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XEROX DISCLOSURE JOURNAL

SELF-REFERENCING Proposed Classification PHOTORECEPTOR POSITION U.S. C1.346/108
SENSOR Int. C1. B41j 02/45
John
R. Andrews

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XEROX DISCLOSURE JOURNAL - Vol. 19, No. 6 November/December 1994 449

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SELF-REFERENCING PHOTORECEPTOR POSITION SENSOR

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450 XEROX DISCLOSURE JOURNAL - Vol. 19, No. 6 NovembedDecember 1994

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SELF-REFERENCING PHOTORECEPTOR POSITION SENSOR

(Cont'd)

A belt marker position sensor is described which has the capability of detecting its own location relative to an actual scan line. The sensor makes this possible by using detectors to locate the optical axis of the scan line relative to the belt hole sensing position and eliminates the need to precisely position the sensor on a production line.

Position sensors are critical to satisfactory color registration in electronic reprographic and printing systems. To establish and maintain registration as each color of a multicolor image is exposed, developed, and transferred, the absolute and relative positions of the photoreceptor, receiver, and exposure line must be accurately known. This is accomplished by a sensor that, in addition to measuring the belt position, determines the position of the sensor relative to the exposure station and therefore guarantees absolute image positioning accuracy.

Figure 1 shows a generic system that has a photoreceptor belt 8 with document process direction edge markers holes 10 at the leading edge of document panels 12,14. Exposure line 16 is also shown. Two belt sensors 18,20 are shown which can measure both image leading edge and skew. Note that in Fig. 1 the two sensors are not located in the same location relative to the scan line in the process direction. Belt position and also skew can be determined with high absolute accuracy with the present sensing technique. Numerous sensor configurations can be proposed that use measurement of the exposure light to be self-referencing. Figure 2 shows one such configuration. The key to the technique is that a detector 22 for the belt marker and detector 26 for the position of the scan...