Xerox Corporation

Carl B Hurwitch

Daniel W MacDonald

Robin E Berman

Mark A Scheuer

Douglas A Lundy

Kip L Jugle

Kenneth S Palumbo

David G Wilcox

Patricia Joanne Donaldson

Anthony L Paolini

Clement J Nagley

Anthony J Paolini

A pair of Electronic Voltmeters (ESV) are utilized to control the photoreceptor charging voltage in a Tri-Level imaging apparatus. One of the ESVs is used to control the voltage increases of a charging device. The other ESV is used to monitor the charge level of the charged area image of a Tri-Level image. When a critical value is sensed the control of the charging device is shifted to the ESV that monitors the charged area image level and limits the output from the charging device to a predetermined target value.

Charged area (CAD) image loss control in a tri-level imaging apparatus

Infra-Red Densitometer (IRD) readings are utilized to check the efficiency of two-pass cleaning of the black toner patch in a tri-level imaging apparatus. The IRD examines the background patch of the tri-level image and declares a machine fault if excessive toner is detected.

Method of using an infra-red densitometer to insure two-pass cleaning

In order to shorten cycle up convergence, a stored or resident image is utilized. It is contained on an external control or pixel board forming a part of the machine image output terminal (IOT). The resident image together with a raster output scanner (ROS) is used to form two charge, V.sub.CAD, two discharge, V.sub.DAD and two background, V.sub.Mod patches in every frame for a total of six patches. A pair of electrostatic voltmeters (ESV) are used to read all six patches and control decisions are made on the basis of the average of the two readings for each voltage level. Because of their physical locations relative to the ROS the readings of one ESV are used in forming the two charge area patches while the other ESV is used in forming the discharge area images. Both ESVs are employed for forming the two background patches.

Cycle up convergence of electrostatics in a tri-level imaging apparatus

A single pass tri-level imaging apparatus and method. Compensation for the effects of dark decay on the background voltage, V.sub.Mod, and the color toner patch, V.sub.tc readings is provided using two ESVs (ESV.sub.1 and ESV.sub.2), the former located prior to the color or DAD housing and the latter after it. Since the CAD and black toner patch voltages are measured (using ESV.sub.2) after dark decay and CAD voltage loss have occurred, no compensation for these readings is required. The DAD image voltage suffers little dark decay change over the life of the P/R so the average dark decay can be built into the voltage target.

Dark decay control system utilizing two electrostatic voltmeters

A process for controlling the amount of film buildup on a photoreceptor surface caused by certain print mode and/or material throughput conditions in a single pass highlight color printer which enables or promotes photoreceptor filming by the DAD toner additive (i.e. zinc stearate). Such filming results in the tri-level Image Push defect. This process utilizes toner coated cleaner brushes to control the film buildup thus preventing the defect. This process defines a functional equation that maintains a toner concentration at the cleaner brush fiber tips thereby controlling photoreceptor filming.

Mac cleaner brush film control

A process for controlling the amount of film buildup on a photoreceptor surface caused by certain print mode and/or material through conditions in a single pass highlight color printer which enables or promote photoreceptor filming by the DAD toner additive (i.e. zinc stearate). Such filming results in tri-level image Push defect. This process utilizes toner coated cleaner brushes to control the film buildup thus preventing the defect. This process defines a functional equation that maintains a certain toner concentration at the cleaner brush fiber tips thereby controlling photoreceptor filming.

Cleaner brush retone film control

Recalculation of electrostatic target values in a tri-level imaging apparatus are utilized to extend the useful life of the photoreceptor (P/R). The increase in residual voltage due to P/R aging which would normally necessitate P/R disposal is obviated by resetting the target voltage for the full ROS exposure when it reaches its exposure limit with current P/R conditions. All contrast voltage targets are then recalculated based on this new target. The new targets are calculated based on current capability of the overall system and the latitude is based on voltage instead of exposure.

Electrostatic target recalculation in a xerographic imaging apparatus

In a single pass, tri-level imaging apparatus, machine cycle down is initiated when the color developer housing is functioning improperly. The voltage level of the color image prior to its development is read using an electrostatic voltmeter (ESV). The voltage level thereof is also read after development. The difference between these two readings is compared to an arbitrary target value and a machine cycle down is initiated if the difference is greater than the target.

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Rochester, NY, United States of America

Carl B Hurwitch