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Browse Prior Art Database

TRANSMISSION DENSITOMETER FOR SOLID AREA DENSITY CONTROL

IP.com Disclosure Number: IPCOM000026094D
Original Publication Date: 1990-Apr-30
Included in the Prior Art Database: 2004-Apr-05
Document File: 2 page(s) / 80K

Publishing Venue

Xerox Disclosure Journal

Abstract

Many copiers use Infra-red reflection measurements of toner patches on the photoreceptor to control solid area copy density. These measurements have a shortcoming, especially for colored toners, in that they lose sensitivity for toner mass loadings greater than approximately 0.4rngkm2, whereas better control could be had if they had sensitivity to 1 mg/cm2 or beyond. Some improvement would be expected if we optimized the wavelength for the toner in use; however, it is reported that a fatigue track shows up in the copy if the toner sensor is operated with visible light.

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XEROX DISCLOSURE JOURNAL

TRANSMISSION DENSITOMETER Proposed Classification FOR SOLID AREA DENSITY
CONTROL
Int. C1. G03g 21/00 Edward W. Connors

US. C1.355/246

Many copiers use Infra-red reflection measurements of toner patches on the photoreceptor to control solid area copy density. These measurements have a shortcoming, especially for colored toners, in that they lose sensitivity for toner mass loadings greater than approximately 0.4rngkm2, whereas better control could be had if they had sensitivity to 1 mg/cm2 or beyond. Some improvement would be expected if we optimized the wavelength for the toner in use; however, it is reported that a fatigue track shows up in the copy if the toner sensor is operated with visible light.

Based on earlier work one would expect that, if we could switch to transmission optical measurements, the sensitivity could be extended to higher massiarea. Furthermore, since the measurement would necessarily be off the P/R we would have more freedom to choose the operating wavelength. What is required to enable this disclosure to be able to generate a powder cloud that is proportional in density to the underlying toner layer to be measured.

To generate the powder cloud from the toner layer one might consider ultrasonics, the powder spray in front of a blade cleaner or air knife schemes. Of perhaps more interest is to use an AC DC biased fine wire above the toner layer.

One embodiment then of this disclosure would be to arrange an optical me...