Browse Prior Art Database

ADC FOR BOTH SOLID AREA & BACKGROUND CONTROL

IP.com Disclosure Number: IPCOM000024657D
Original Publication Date: 1981-Aug-31
Included in the Prior Art Database: 2004-Apr-02
Document File: 2 page(s) / 54K

Publishing Venue

Xerox Disclosure Journal

Abstract

In control systems for xerographic copier/duplicators, it is known that the density of solid area development can be controlled by adjusting the bias of the roller of a magnetic brush development device in accordance with information derived from measurement of toner concentration. Since there is no corresponding control for background density, it is customary to set the development roller bias high enough to compensate for the degradation of a new developer charge. The bias set point is generally a compromise between adequate initial solid area and line densities and acceptable background density during the life of the developer.

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XEROX DISCLOSURE JOURNAL

Proposed Classification

Int. C1. B67d U-S* CI- 118/657

In control systems for xerographic copier/duplicators, it is known that the density of solid area development can be controlled by adjusting the bias of the roller of a magnetic brush development device in accordance with information derived from measurement of toner concentration. Since there is no corresponding control for background density, it is customary to set the development roller bias high enough to compensate for the degradation of a new developer charge. The bias set point is generally a compromise between adequate initial solid area and line densities and acceptable background density during the life of the developer.

By means of the method described in this disclosure, the need for setting the development bias at an excessively high fixed level is avoided by continuous automatic adjustment as the developer ages. The signal for controlling this adjustment is derived from a minicomputer into which is fed information on the slope and intercept of the image density versus development potential function. This information is produced by a reflectance-type sensor which measures the reflection density of toner images developed on a series of test areas on the photoreceptor which are held at fixed potentials.

Volume 6 Number 4 July/August 1981 157

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  XEROX DISCLOSURE JOURNAL Volume 6 Number 4 July/August 1981

158

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