Abstract:
The relationship between first and second side images is evaluated to determine how the position of the paper and/or the size and arrangement of an image can be manipulated to compensate for paper shrinkage caused by fusing. Show through is reduced by performing setup to adjust a pixel clock frequency and/or a photoreceptor speed, determining a residual magnification error, determining margin shifts to compensate for the residual magnification error, and applying the margin shifts. Paper shrink effects on registration can be compensated for using determinations made during a typical printer setup. Show through errors can be reduced without using a paper conditioner to pre-shrink or re-wet the paper. In simplex and duplex printing, the show through errors worsen as the image moves away from the registration edge. Using information obtained during setup, a margin shift is determined that results in a significant reduction in the maximum show through for each image.
Abstract:
Initial setup of image to sheet (IOS) or image to paper (IOP) registration in a printing device such as, for example, an electrographic printer, is accomplished in a single step that uses an initial set of measurements to determine and correct each of the independent registration errors, including image squareness/ROS skew, image skew/paper skew, lateral magnification, process magnification, lateral direction IOS or IOP position, and process direction IOS or IOP position simultaneously. A set of algorithms is used to perform a series of geometrical transformations to determine each of the six errors affecting IOS or IOP registration.
Abstract:
The disclosed embodiments are directed to a method and apparatus for duplex imaging in a tandem print engine system. The features of the disclosed embodiments include imaging a first side of a sheet in a first marking module in the system, inverting the sheet, and imaging a second side of the sheet in a second marking module in the system one pitch after N revolutions of a photoreceptor following the first side imaging.
Abstract:
A method and apparatus for inverting sheets traveling through a machine with an inverter having a reversing chute and a reversing nip in the reversing chute. An incoming sheet is receiving into the reversing chute. The reversing nip reverses the direction of travel of the sheet and drives sheet out of the reversing chute. A gap is opened in said reversing nip, while the outgoing sheet still extends through the reversing nip. A subsequent incoming sheet is received into the reversing chute and through the gap in the reversing nip, while the outgoing sheet still extends through the gap. The gap is closed after the outgoing sheet has exited the reversing nip, such the reversing nip reverses the direction of travel of the subsequent incoming sheet and drives the sheet out of the reversing chute. The machine may be a printing or copying machine.
Abstract:
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.
Abstract:
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.
Abstract:
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.
Abstract:
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.
Abstract:
A marking device is controlled to mark a media sheet with halftone dots selected from a set of image halftone dot representations. The marking device is controlled to mark a monitored surface with halftone dots selected from a set of control halftone dot representations to form test patches of different nominal marking densities. Measured marking densities are acquired using a density sensor for the test patches marked on the monitored surface. The set of control halftone dot representations is updated based on the measured marking densities and the nominal marking densities.
Abstract:
Disclosed is a printing apparatus and method to correct for image non-uniformities. The printing apparatus comprises a photoreceptor (P/R) belt charging device positioned to charge the P/R belt after an image is transferred to a media sheet. Subsequently, an image sensing device scans the P/R belt residual image or patches to detect image non-uniformities.