Xerox Corporation

Daniel W MacDonald

Mark A Scheuer

Carl B Hurwitch

Patricia Joanne Donaldson

Robin E Berman

Eric Michael Gross

Eric Scott Hamby

Edward W Smith, Jr

Paul A Garsin

John Buranicz

Douglas A Lundy

Joseph W Ward

Prasad P Padmanabhan

Kip L Jugle

Kenneth S Palumbo

David G Wilcox

Anthony L Paolini

Clement J Nagley

Anthony J Paolini

A method and system for a color xerographic machine determines a lower bound for the ROS power levels so that color defects are not produced by light attenuation from one or more layers of toner particles on a latent image. The method computes a minimum ROS power level for the photoreceptor at its maximum and minimum charge levels. The minimum ROS power level is the level at which the discharge voltage does not drop beyond a maximum discharge voltage difference. The difference is related to a toner particle density that affects color reproduction. The minimum ROS power levels for the minimum and maximum photoreceptor charge levels are used to compute a functional relationship for minimum ROS power levels at other photoreceptor charge levels. Thereafter, the minimum ROS power level function may be used to compute minimum ROS power levels for other photoreceptor charge levels. The computed minimum ROS power levels may be used to control the power levels used during color reproduction performed by the machine.

System and method for controlling the lower power bound for a raster output scanner in a color xerographic printer

The present invention generally relates to an imaging system, and more specifically, a method and apparatus for accurately predicting toner usage and hence toner dispensing requirements in an imaging system. The toner concentration control system maintains toner concentration in a developer structure, which is connected to a dispenser containing toner. The toner concentration control system includes a toner mass estimator providing a toner mass estimate of the toner mass in the developer structure to be applied to the photoreceptor; a feed forward dispense unit receiving the toner mass estimate and transmitting a feed forward dispense command based on the toner mass estimate; a toner concentration target adjusted by toner age, toner break-in and temperature in the developer structure; a feed back dispense unit receiving the adjusted toner concentration target and transmitting a feedback dispense command; and a total dispense unit receiving the feed forward dispense command and the feedback dispense command, and outputting total dispense command to the dispenser, which dispenses the toner to the developer structure in accordance with the total dispense command.

Toner concentration control for an imaging system

The present invention generally relates to an imaging system, and more specifically, a method and apparatus for accurately predicting toner usage and hence toner dispensing requirements in an imaging system. More particularly, the present invention relates to a toner concentration control system for maintaining toner concentration in a developer structure, which is connected to a dispenser containing toner. The toner concentration control system comprises: a sensor, reading the toner concentration; means for determining a toner age correction of toner concentration read by the sensor based on toner age of the toner in the developer structure; means for adjusting a toner concentration target based on the correction; and means for generating a feedback dispense command based on the adjusted toner concentration target to dispense toner into the developer structure to maintain the toner concentration in the developer structure.

Feedback toner concentration control for an imaging system

The present invention generally relates to an imaging system, and more specifically, a method and apparatus for accurately predicting toner usage and hence toner dispensing requirements in an imaging system. More specifically, the present invention relates to a toner concentration control system for maintaining toner concentration in a developer structure, which is connected to a dispenser containing toner.

The present invention generally relates to an imaging system, and more specifically, a method and apparatus for accurately predicting toner usage and hence toner dispensing requirements in an imaging system. More particularly, the present invention relates to a toner concentration control system for maintaining toner concentration in a developer structure, which is connected to a dispenser containing toner.

The present invention generally relates to an imaging system, and more specifically, a method and apparatus for accurately predicting toner usage and hence toner dispensing requirements in an imaging system. More, specifically, the present invention relates to a toner concentration control system for maintaining toner concentration in a developer structure, which is connected to a dispenser containing toner. The toner concentration control system including: a toner mass estimator providing a toner mass estimate of the toner mass in the developer structure to be applied to the photoreceptor; a feed forward dispense unit receiving the toner mass estimate and transmitting a feed forward dispense command based on the toner mass estimate; a toner concentration target adjusted for toner age in the developer structure; a feed back dispense unit receiving the adjusted toner concentration target and transmitting a feedback dispense command; and a total dispense unit receiving the feed forward dispense command and the feedback dispense command, and outputting total dispense command to the dispenser, which dispenses the toner to the developer structure in accordance with the total dispense command.

Feed forward and feedback toner concentration control for an imaging

The present invention generally relates to an imaging system, and more specifically, a method and apparatus for accurately predicting toner usage and hence toner dispensing requirements in an imaging system. More specifically, the present invention relates to a toner concentration control system for maintaining toner concentration in a developer structure, which is connected to a dispenser containing toner. The toner concentration control system includes a toner mass estimator providing a toner mass estimate of the toner mass in the developer structure to be applied to the photoreceptor; a feed forward dispense unit receiving the toner mass estimate and transmitting a feed forward dispense command based on the toner mass estimate; a toner concentration target adjusted for toner break-in in the developer structure; a feed back dispense unit receiving the adjusted toner concentration target and transmitting a feedback dispense command; and a total dispense unit receiving the feed forward dispense command and the feedback dispense command, and outputting total dispense command to the dispenser, which dispenses the toner to the developer structure in accordance with the total dispense command.

In a xerographic printer for tri-level highlight color imaging, two electrostatic voltmeters (ESVs) are used to interpolate the electrostatic potential at a particular location along the path of the photoreceptor belt. Anomalous ESV readings, such as would be caused by dirt interfering with the ESV itself as opposed to systemic changes in the whole apparatus, are detected by having the printer enter a 'test mode' in which test patches having minimal charge are monitored by the ESVs. The low-charge test patches enable noise related directly to the ESVs to be isolated from other possible sources of noise. The noise which results from ESV malfunctioning is compensated for when the printer returns to operation.

System for controlling electrostatic voltmeters in a tri-level highlight

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 a single pass tri-level imaging apparatus, a pair of Electrostatic Voltmeters (ESV) are utilized to monitor various control patch voltages to allow for feedback control of Infra-Red Densitometer (IRD) readings. The ESV readings are used to adjust the IRD readings of each toner patch. For the black toner patch, readings of an ESV positioned between two developer housing structures are used to monitor the patch voltage. If the voltage is above target (high development field) the IRD reading is increased by an amount proportional to the voltage error. For the color toner patch, readings using an ESV positioned upstream of the developer housing structures and the dark decay projection to the color housing are used to make a similar correction to the color toner patch IRD readings (but opposite in sign because, for color, a lower voltage results in a higher development field).

ESV readings of toner test patches for adjusting IRD readings of

Two sets of targets, one for use during cycle up convergence of electrostatics and one during runtime enable single pass cleaning of developed patches, during cycle up convergence. To this end, different targets from those used during runtime are used for the preclean, transfer and pretransfer dicorotrons during cycle up. Proper charging of the photoreceptor during runtime and cycle up convergence is also enabled by the provision of two charging targets, one for each mode of operation.

Tri-level imaging apparatus using different electrostatic targets for

Toner patch generation for use in tri-level imaging is effected using a laser ROS. Two toner patches are formed using a single toner patch generator of the type commonly used in the prior art. The patch generator, used by itself serves to form one toner patch latent image and together with the ROS exposure device of the imaging apparatus is used to form the other toner patch latent image.

ROS assisted toner patch generation for use in tri-level imaging

The Infra-Red Densitometer (IRD) readings of developed toner patches in a tri-level imaging apparatus are compared to target values stored in Non-Volatile Memory (NVM) and are also compared to the previous IRD reading. Toner dispensing decisions (i.e. addition or reduction) are based on both comparisons. In this manner, not only are IRD readings examined as to how far the reading is from the target, they are examined as to current trend (i.e. whether the reading is moving away from or toward the target). Thus, if the IRD reading indicates that the toner concentration is low but is heading toward the target then the amount of added toner is somewhat reduced. If the IRD reading indicates that the toner concentration is low and is heading away from target (getting lower) then some extra toner is dispensed

Toner dispensing rate adjustment using the slope of successive IRD

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.

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Farmington, NY, United States of America

Daniel W MacDonald