Xerox Corporation

Brian Robert Conrow

David Mark Kerxhalli

Douglas Raymond Taylor

David Clark Craig

Shawn Patrick Updegraff

Jeffrey J Folkins

Peter Paul

Howard A Mizes

Paul Allen Hosier

Michael John Martin

Robert J Kleckner

W Bradford Willard

Lalit Keshav Mestha

Patricia Joanne Donaldson

Jack Gaynor Elliot

Christine Ann Steurrys

Keith A May

Paul Lynn Jacobs

Stuart Alan Schweid

R Enrique Viturro

Stanley John Wallace

Moritz Patrick Wagner

James Patrick Calamita

Claude Fillion

Jonathan Byron Hunter

Mark Andrew Omelchenko

Joseph M Wing

Robert E Rosdahl, Jr

Andrew James Bonacci

Alan G Schlageter

Robert Edward Hildebrand

Brian J Perry

Fan Shi

Kimberly Anne Stoll

Michael J Thomas

Elden R Morrison

Olga Y Ramirez

Ronald E Shaul

William B Willard

Paul A Hosier, Iii

A three-dimensional object printer ejects drops of a build material from a plurality of ejectors in a first printhead to form an object on a first region of a member and ejects drops of a support material from a plurality of ejectors in a second printhead to support the object on the first region of the member. The second printhead ejects drops of the support material onto a second region of the member that is separate from the first region to form a substrate layer. The first printhead ejects drops of the build material onto the substrate layer to form a printed test pattern. An image sensor generates image data of the printed test pattern to identify an inoperable ejector in the first printhead.

System and method for test pattern formation during three-dimensional object printing

A printer uses closed loop control to keep material drops ejected by a printhead within a predetermined range. The printer forms at least two objects on a support member and then operates a specular sensor array to obtain image data of the two objects on the support member. The two objects have different predetermined heights to enable a controller in the printer to identify the mass or volume of the material drops forming the objects to adjust operational parameters of the printer to maintain the mass or volume of the material drops in the predetermined range.

System and method for controlling material drop volume in three dimensional object printing

A printer compensates for printing errors occurring during production of the layers for the formation of an object in a three-dimensional printer. The printer includes an optical sensor that generates data corresponding to edges of each layer of the object after each layer is printed. Differences between the raster data used to eject the material to form a layer and the data received from the optical sensor are used to modify the raster data that operates a printhead to form a next layer in the object.

System for adjusting operation of a printer during three-dimensional object printing using an optical sensor

Devices and methods detect an amount of toner on a photoreceptor caused by a printing process, and calculate a reload signal using a processor. The reload signal shows the amount of toner being reloaded on a donor roll from a toner container to replace the toner being removed from the donor roll during the printing process (as detected by an optical sensor). Such devices and methods generate a toner concentration (TC) sensor response representing a concentration of toner particles within the toner/developer mixture using a TC sensor, calculate a calibration sensor relationship between the TC sensor response and the reload signal, using the processor, based on changes in the TC sensor response and the reload signal that occur while changing the toner concentration during the printing process, and calibrate the TC sensor based on differences between the calibration sensor relationship and a previously established model relationship using the processor.

Calibrating toner concentration sensors using reload measurement

A method of printer operation enables visual detection of defective inkjets. The method includes operating inkjets in a predetermined number of printheads that eject a same color of ink to form a test pattern having three portions. One portion is printed by the even-numbered inkjets in each printhead, one portion is printed by the odd-numbered inkjets in each printhead, and a third portion is printed by all of the inkjets in each printhead. The portions are printed immediately adjacent to one another in a process direction with the third portion between the other two portions.

System and method for visually detecting defective inkjets in an inkjet imaging apparatus

A method of calibrating a printing system for positioning at least one printed image, the printing system includes a first image bearing surface, the method includes: a) forming a background pattern and at least three fiducials on the first image bearing surface, wherein the background pattern is larger than a first printed image and the at least three fiducials are within an area formed by the first printed image; b) transferring a portion of the first printed image to a second image bearing surface; c) measuring a first residual image on the first image bearing surface, wherein the first residual image is a portion of the background pattern and the at least three fiducials remaining on the first image bearing surface after the step of transferring; and, d) calculating at least one calibration parameter for the printing system based on the measuring of the first residual image.

Automated positioning of printed images

The present disclosure provides a method of forming a toner image, comprising: electrically charging a photoreceptor by a charging roller being brought into contact with the photoreceptor, the photoreceptor comprises a photosensitive coating layer on a cylindrical conductive substrate; correcting line width variation using an exposure adjustment calculation (y); and, wherein the exposure adjustment calculation uses a factor based on a ratio (m) of a coefficient of line width variation due to toner age divided by the coefficient of line width variation due to laser power.

Correction of line width variation due to toner age

An image forming apparatus includes a sensor that is configured to detect a property of a developer material, a transport unit that is operatively in contact with the developer material and that is configured to move the developer material toward a recording medium, and a controller that receives the property of the developer material from the sensor unit and sets a voltage of the transport unit, wherein the voltage is determined based on the property of the developer material received from the sensor.

Reducing reload image quality defects

What is disclosed is a novel system and method for xerographic Dmax control based upon measurements made on the printed paper using an inline spectrophotometer (ILS) or similar device. The disclosed method is based upon directly measuring the color to actuator sensitivity. Each of the separations is controlled independently using an actuator specific to that color separation. The present method is effective at controlling the color of the solid primaries. The fact that the vector of change is highly correlated with solid color variation seen in the field suggests that the teachings hereof effectively increase the solid color stability. Increased solid color stability increases the color stability throughout the printer gamut and the stability of the gamut boundaries, which increases the robustness of gamut mapping algorithms. Advantageously, the present method can be combined with existing ILS-based maintenance architectures.

Digital printing control using a spectrophotometer

A method for controlling a tone reproduction curve of an image printing system includes generating an actual printed image tone reproduction curve using printed image data from a printed image sensor; determining a set of adjusted contone values by comparing the actual printed image tone reproduction curve with a target printed image tone reproduction curve, where the adjusted contone values being representative of the print contone values at which target color density data of the printed image is achieved in the image printing system; and determining adjusted image transfer surface reflectance data to update a target image transfer surface tone reproduction curve, where the adjusted image transfer surface reflectance data being obtained by interpolating the target image transfer surface tone reproduction curve at the adjusted contone values; and controlling subsequent toner image data to achieve the updated target image transfer surface tone reproduction curve.

Method and system for digitally controlling image printing system to achieve desired color density of printed image

Line width of images marked by an image marking device is adjusted by reading a calibration patch marked by the marking device, and then adjusting one or more settings of the marking device, such as exposure intensity or cleaning field intensity, independent of the digital control of the tone reproduction curve so that the line width of subsequently marked images becomes closer to a target value. A digital control may be implemented to compensate for the impact of the modification of the one or more settings on the tone reproduction curve.

Selection of exposure intensity and cleaning field intensity setpoints for optimum line width using sensor reading

Streak compensation in a digital printer is provided utilizing a spatially varying Printer Model and Run Time updates to generate Spatially Varying Tone Reproduction Curves (STRCs) which are used as actuators to compensate for streaks during run time. A full width array sensor is used to measure streak profiles and the STRCs are used as actuators to compensate for streaks. Streak profile measurements taken at a limited number of area coverage levels combined with a Printer Streaks Basis Function Model are used to estimate and project the streak behavior at all area coverage levels and at all inboard-to-outboard spatial locations. The projection is then used in a pixel-wise error feedback control scheme to drive each profile to a desired shape, thereby compensating for streaks.

Streak compensation using model based projections for run time updates

A method and system are provided for characterizing performance of a printer across a plurality of halftone screens. A first non-uniformity profile is generated by measuring printer performance. Cross-position differences between the first non-uniformity profile and selected corresponding cross-positions of a second halftone screen are detected. A scaling factor is computed relating the detected differences. Printer performance with the second halftone screen is predicted by applying the scaling factor associated with the second halftone screen to the non-uniformity profile of the first halftone screen.

Method and system for correlating of uniformity compensations across halftone screens

A method for monitoring an image printing system that prints color images on an image bearing surface movable in a process direction is provided. The method includes placing marking material to form a row comprising a plurality of registration marks on the image bearing surface, wherein each row of registration marks extends along a cross-process direction transverse to the process direction; detecting a position of each registration mark using a linear array sensor extending in the cross-process direction, wherein the position of each registration mark is detected in both the process and cross-process direction; determining a process direction misregistration between the registration marks of each row in the process direction and cross-process direction misregistration between registration marks from each of the rows.

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Webster, NY, United States of America

Brian Robert Conrow