Browse Prior Art Database

COLORED TONER OPTICAL DEVELOPABILITY SENSOR WITH IMPROVED SENSING LATITUDE

IP.com Disclosure Number: IPCOM000026023D
Original Publication Date: 1989-Oct-31
Included in the Prior Art Database: 2004-Apr-05
Document File: 2 page(s) / 127K

Publishing Venue

Xerox Disclosure Journal

Abstract

measurement o P the amount of unfused toner that is developed onto the One important rocess control in electrophotographic applications is the charge retentive surface. In Infrared Reflection Densitometer (IRD) sensors, such as that used, for example, in the Xerox 1065 copier, heretofore primarily for use with black toners, at a test patch exposed and developed specifically for process control purposes, a light emitting infrared diode illuminates the tonerlsurface combination, and a hotodiode is positioned to

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'EROX A DISCLOSURE JOURNAL

COLORED TONER OPTICAL Proposed Classification DEVELOPABILITY SENSOR WITH U.S. C1.355/14 IMPROVED SENSING LATITUDE
Michael A. Butler
Susan G. Lysy
Paul W. Morehouse, Jr.

Int. C1. G03g 21/00

One important rocess control in electrophotographic applications is the

charge retentive surface. In Infrared Reflection Densitometer (IRD) sensors, such as that used, for example, in the Xerox 1065 copier, heretofore primarily for use with black toners, at a test patch exposed and developed specifically for process control purposes, a light emitting infrared diode illuminates the tonerlsurface combination, and a hotodiode is positioned to

more toner is developed onto the surface, the amount of light specularly reflected from the toner/surface combination is attenuated. The process control measurement is the ratio between light reflected from the tonerlsurface combination and the bare surface. This ratio is referred to as the specular reflection ratio.

It has been found that when specular reflection-based developability sensors are used with colored toners, the specular reflection ratio becomes invariant for DMA (developed toner mass per unit area) values smaller than those associated with optimal control values. This decrease in sensitivity appears to result from scatterin of light by colored toners, since colored toners tend

specular reflection ratio is invariant with a value large compared to zero, as a result of the large angle subtended by the detector, and required to provide latitude in mounting the sensor with respect to the surface. Thus, for colored toners, both specular and diffusely reflected light is detected by the sensor. The diffusely reflected light tends to obscure changes in the specular component, and gives signal saturation at a substantial offset value.

U.S. Patent 4,553,033 to Hubble, III et al. teaches an LCIRD of the type useful for detecting the specular component of reflected light.

Certain toners that give the appearance of black toner may be composed of a combination of colored pigments mixed to present a black appearance, rather than carbon black pigments. It is of interest that such tone...