Abstract: An electrophotographic printing system for printing with a set of toners including a white toner. A plurality of printing modules are configured to print respective toner patterns, each including a toner image printed onto a receiver medium being transported on a transparent transport web and a corresponding registration mark positioned outside a border of the receiver medium. A first registration mark sensing system is positioned to detect the registration marks printed with a first subset of the toners that doesn't include the white toner. A second registration mark sensing system is positioned to detect the registration marks printed with a second subset of the toners that includes the white toner. The registration mark sensing systems each include a reflector plate positioned behind the transport web. The reflector plate for the first registration mark sensing system is white, and the reflector plate for the second registration mark sensing system is black.

Abstract: An electrophotographic printing system for printing with a set of toners including a white toner. A plurality of printing modules are configured to print respective toner patterns, each including a toner image printed onto a receiver medium being transported on a transparent transport web and a corresponding registration mark positioned outside a border of the receiver medium. A first registration mark sensing system is positioned to detect the registration marks printed with a first subset of the toners that doesn't include the white toner. A second registration mark sensing system is positioned to detect the registration marks printed with a second subset of the toners that includes the white toner. The registration mark sensing systems each include a reflector plate positioned behind the transport web. The reflector plate for the first registration mark sensing system is white, and the reflector plate for the second registration mark sensing system is black.

Abstract: A digital printing system having a linear printhead includes corrections for in-track position errors. A data processing system implements a method for determining an in-track position function which includes printing a test target including a plurality of alignment marks, automatically analyzing a captured image of the printed test target to determine a measured in-track position for each of the alignment marks, comparing the measured in-track positions for the alignment marks to reference in-track positions to determine measured in-track position errors, and determining an in-track position correction function responsive to the measured in-track position errors. The in-track position correction function specifies in-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling an input digital image responsive to the in-track position correction function.

Abstract: A method for correcting in-track position errors in a digital printing system having a linear printhead includes printing a test target including a plurality of alignment marks. A data processing system is used to automatically analyze a captured image of the printed test target to determine a measured in-track position for each of the alignment marks. The measured in-track positions for the alignment marks are compared to reference positions to determine measured in-track position errors. An in-track position correction function is determined responsive to the measured in-track position errors, wherein the in-track position correction function specifies in-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling an input digital image responsive to the in-track position correction function.

Abstract: A digital printing system having a linear printhead includes corrections for in-track position errors. A data processing system implements a method for determining an in-track position function which includes printing a test target including a plurality of alignment marks, automatically analyzing a captured image of the printed test target to determine a measured in-track position for each of the alignment marks, comparing the measured in-track positions for the alignment marks to reference in-track positions to determine measured in-track position errors, and determining an in-track position correction function responsive to the measured in-track position errors. The in-track position correction function specifies in-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling an input digital image responsive to the in-track position correction function.

Abstract: A method for correcting in-track position errors in a digital printing system having a linear printhead includes printing a test target including a plurality of alignment marks. A data processing system is used to automatically analyze a captured image of the printed test target to determine a measured in-track position for each of the alignment marks. The measured in-track positions for the alignment marks are compared to reference positions to determine measured in-track position errors. An in-track position correction function is determined responsive to the measured in-track position errors, wherein the in-track position correction function specifies in-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling an input digital image responsive to the in-track position correction function.

Abstract: A focus adjustment mechanism for adjusting a focus position of a printhead includes a rotatable pin that is rotatable around a pin axis. The rotatable pin includes a cam section located having a surface whose radial distance from the pin axis varies around its perimeter, and a gripping feature. An adjustment plate includes a gripping feature and is adapted to fit over and engage with the gripping feature of the rotatable pin such that the adjustment plate rotates together with the rotatable pin. A fastener fastens the adjustment plate to a support structure when the adjustment plate is positioned in a desired orientation. The printhead includes a frame feature which is pulled firmly against the cam section of the rotatable pin such that as the rotatable pin is rotated the frame feature rides on the surface of the cam section thereby adjusting the focus position of the printhead.

Abstract: A method for preventing contamination of a lens assembly by charged particles on an image bearing surface in an electrophotographic printer includes providing a conductive electrode with an opening adjacent the lens assembly; charging the conductive electrode with a variable voltage power supply; and matching a voltage on the image bearing surface with the variable voltage power supply.

Abstract: Correction data is produced for density errors in prints produced using a printer. While printing a test image, the periods of rotation of one or more rotatable imaging members arranged along a receiver feed path in the printer are measured using respective period sensors. The printed test image is measured in both the cross-track and in-track directions and a two dimensional map of the one or more period sensors is determined. A reproduction error signal representing deviation from aim density is determined. The variations from the data at measured periods in one or both directions are used to produce a correction signal.

Abstract: A method for reducing toning spacing sensitivity in an electrophotographic process is disclosed. The method includes providing a rotating magnetic member within a conductive non-magnetic development sleeve; providing a developer to the non-magnetic development sleeve for use with the rotating magnetic member including: (i) composite magnetic particles comprising strontium ferrite and lithium ferrite phases and (ii) toner particles. The method further includes moving a charged receiving medium into a toner transfer relationship with the developer on the non-magnetic development sleeve so as to provide a developed image on the receiving medium with reduced toning spacing sensitivity.

Abstract: Correction data is produced for density errors in prints produced using a printer. While printing a test image, the periods of rotation of one or more rotatable imaging members arranged along a receiver feed path in the printer are measured using a period sensor. The printed test image is measured in the cross-track direction and a one dimensional map of the period sensors is determined. A reproduction error signal representing deviation from aim density is determined. The variations from the data at measured periods in one or both directions are used to produce a correction signal.

Abstract: Correction data is produced for density errors in prints produced using a printer. While printing a test image, the periods of rotation of one or more rotatable imaging members arranged along a receiver feed path in the printer are measured using a period sensor. The printed test image is measured in the cross-track direction and a one dimensional map of the period sensors is determined. A reproduction error signal representing deviation from aim density is determined. The variations from the data at measured periods in one or both directions are used to produce a correction signal.

Abstract: Correction data is produced for density errors in prints produced using a printer. While printing a test image, the periods of rotation of one or more rotatable imaging members arranged along a receiver feed path in the printer are measured using respective period sensors. The printed test image is measured in both the cross-track and in-track directions and a two dimensional map of the one or more period sensors is determined. A reproduction error signal representing deviation from aim density is determined. The variations from the data at measured periods in one or both directions are used to produce a correction signal.

Abstract: Printers and cleaning systems are provided. A cleaning system has an actuator that moves the electrostatic imaging member in a second direction opposite the first direction and a frame positions a mounting within a first range of mounting distances from the electrostatic imaging member with the mounting holding a cleaning blade at a holding angle that causes a free length of the cleaning blade to extend along a first direction to position a cleaning end of the cleaning blade to engage the electrostatic imaging member for movement therewith. The electrostatic imaging member urges the cleaning end in the second direction to deflect the cleaning blade to extend along the second direction to position the cleaning end to wipe the electrostatic imaging member and the free length, the holding angle and the working angle cause the cleaning edge to wipe at a working angle between about 85 and 89 degrees.

Abstract: Methods are provided for controlling airflow across a width of a charger support area having a charger housing supporting a corona charger that is proximate to a primary imaging member. In one method, a flow of air is provided proximate an inlet side of the charger housing area and a deflection surface is used to deflect the flow of air from a first direction to a second direction leading to an impact surface against which the flow of air is disbursed. The impact surface is outside of the width of the charger housing so that the air flow can supply a volume of disbursed air into the charger housing and primary imaging member that is sufficient to create a pressure that causes the disbursed air to move to an outlet on an opposite side of the area without directly exposing the charger or the primary imaging member.

Abstract: Airflow management systems for a charger support area having a charger housing supporting a corona charger that is proximate to a primary imaging member are provided. In one embodiment an air flow management system has an air supply providing flow of air proximate an inlet side of the charger housing area and a deflection surface positioned to deflect the flow of air from a first direction to a second direction leading to an impact surface against which the flow of air is disbursed. The impact surface is outside of the width of the charger housing and the primary imaging member so that the air flow can supply a volume of disbursed air into the charger housing area that is sufficient to create a pressure that causes the disbursed air to move to an outlet on an opposite side of the area without exposing the charger or the primary imaging member to the flow.

Abstract: Methods are provided for automatic cross-track density correction for a print engine having a print head that forms lines of picture elements on a receiver based upon lines of pixel values. In one aspect of the method, the print engine is caused to print a first print having a plurality of different areas along a cross-track direction with target densities and data is received from which measured densities for different ones of the plurality of different areas can be determined. A line density adjustment function is based upon a functional relationship between a cross track position of different ones of the areas and a difference between the measured density and the target density at the different ones of the areas. A production print is subsequently printed according to lines of pixel values for the production print modulated by the line density adjustment function.

Abstract: An electrophotographic printer includes a rotatable photoreceptor adapted to receive dry toner and a rotatable toning member arranged with respect to the photoreceptor to supply toner thereto. A seal includes a complaint contact member and a non-contact member. The contact member is arranged in mechanical contact with the photoreceptor. The non-contact member is spaced apart from the surface of the toning member by a selected non-zero distance, the selected distance being greater than zero. This reduces dusting.

Abstract: A metering skive for a dry electrophotographic (EP) printer is mounted on a retractable skive mount. The skive mount is spring-loaded to a mounting block, and a stop pin sets the distance between the skive mount and the mounting block. A movable spacer with a plurality of laterally-separated regions of respective, different thicknesses is mounted between the head of the stop pin and the mounting block. A retractor can be operated to pull the skive mount towards the mounting block so the spacer can be moved to select a desired spacing between the mounting block and the skive mount, and thus a desired gap between the metering skive and the toning member in the printer.

Abstract: Airflow management systems for a charger support area having a charger housing supporting a corona charger that is proximate to a primary imaging member are provided. In one embodiment an air flow management system has an air supply providing flow of air proximate an inlet side of the charger housing area and a deflection surface positioned to deflect the flow of air from a first direction to a second direction leading to an impact surface against which the flow of air is disbursed. The impact surface is outside of the width of the charger housing and the primary imaging member so that the air flow can supply a volume of disbursed air into the charger housing area that is sufficient to create a pressure that causes the disbursed air to move to an outlet on an opposite side of the area without exposing the charger or the primary imaging member to the flow.