Abstract: A method of aligning a printhead is described herein. The method includes accelerating a media along a process path, controlling a first printhead to form a first mark upon the accelerating media, detecting the first mark on the accelerating media, comparing a first mark detection data with first printhead desired alignment data, determining a first correction based upon the comparison of the first mark detection data, and modifying an alignment of the first printhead based upon the determined first correction.

Abstract: Defects in an image forming system may give rise to scratched fiducials, missing fiducial regions, or other defects in an image that can run parallel to the process direction. The present disclosure provides for a fiducial compensation method and system for detecting defects thereby allowing spatial tone reproduction curves to be calculated and applied to a digital image in order to eliminate printed streaks due to a photoreceptor's non-uniformities.

Abstract: Systems and methods are provided for monitoring jets of an image device. The detection is implemented using a data processor that monitors information sent to a jet and using an image sensor that monitors an image being printed or an image after being printed. A detector detects the difference between the image being printed and/or the image after printing to the information sent to the jet, and identifies a faulty jet based on the difference detected.

Abstract: A method of detecting print head roll begins with the formation of a test pattern on an image receiving surface. The test pattern includes a plurality of marks arrayed across the image receiving surface in a cross-process direction with each mark in the plurality being formed by a different nozzle of a print head. The cross-process direction positions of each mark in the plurality of marks are then detected; and the detected cross-process direction positions are correlated to a print head roll value for the print head.

Abstract: A system and method for controlling the cross-process position of ink print heads including identifying a first roll error frequency related to a circumference of a first roll, identifying a first roll error phase with respect to a reference location along a process path, identifying a first roll error amplitude of cross-process motion, identifying a second roll error frequency related to a circumference of a second roll, identifying a second roll error phase with respect to the reference location, identifying a second roll error amplitude of cross-process motion, and controlling the cross-process position of a first and second print head based upon the identified first roll error frequency, first roll error phase, first roll error amplitude, second roll error frequency, second roll error phase, and second roll error amplitude, wherein the first print head is axially spaced apart from the second print head along the process direction.

Abstract: A method evaluates image quality in an ink printing system and generates data values for altering the operation of the ink printing system. The method includes generating an ink image on an ink image receiving member that corresponds to a digital image stored in the ink printing system, generating a scanned image signal corresponding to the ink image, generating firing signal waveform adjustments and image data adjustments with reference to the scanned image signal corresponding to the ink image, and operating a printhead in an ink imaging system with reference to the firing signal waveform adjustments and the image data adjustments.

Abstract: Engine response curves (RCs) can be used for streak compensation for printed documents. A feedback control paradigm can be included to effect RC compensation. Singular Value Decomposition (SVD) can be used to represent each RC in the collection of spatial RC data as a linear combination of basis vectors. RCs are approximated by selecting the first few basis vectors, the approximation aiding in noise rejection and reducing computation in the controller by reducing dimensionality of the RC data from gray levels to the number of SVD bases selected. An optimal subset of RCs is selectable from the set of approximated RCs by clustering the SVD weights, the clustered SVD weights producing TRCs that span all engine response RCs generated by a printer. Compensation RCs are constructible using reduced number of bases and clustered SVD weights.

Abstract: Systems and methods are provided for detecting process direction registration errors in a printer. The errors are detected by analyzing a metric of a dash minimum response obtained from a test pattern. The test pattern contains dashes. At least one dash is shifted in the process direction in relation to another dash.

Abstract: A system and method for controlling the cross-process position of ink print heads including identifying a first roll error frequency related to a circumference of a first roll, identifying a first roll error phase with respect to a reference location along a process path, identifying a first roll error amplitude of cross-process motion, identifying a second roll error frequency related to a circumference of a second roll, identifying a second roll error phase with respect to the reference location, identifying a second roll error amplitude of cross-process motion, and controlling the cross-process position of a first and second print head based upon the identified first roll error frequency, first roll error phase, first roll error amplitude, second roll error frequency, second roll error phase, and second roll error amplitude, wherein the first print head is axially spaced apart from the second print head along the process direction.

Abstract: Defects in an image forming system may give rise to visible streaks, or one-dimensional defects in an image that run parallel to the process direction. One known method for compensating for streaks introduces a separate tone reproduction curve for each pixel column in the process direction. A compensation pattern according to this invention has alignment marks before and after a halftone compensation region. The alignment marks provide alignment between the printer pixel grid and a scanning pixel grid. The line width of each alignment mark and the gray level in each pixel column of each gray level portion is measured and analyzed to produce a local tone reproduction curve for each pixel column and associated line width. The line widths of the alignment marks can be remeasured to adjust the local tone reproduction curves to compensate for the streak defect when printing.

Abstract: Disclosed is a method and system for compensating for printer cross-process nonuniformity. The method and system provide a means to offset a cross-process uniformity profile associated with an image output device, such as a printer, where process direction noise is measured and the cross-process uniformity profile is adjusted accordingly to provide a better representation of the image output device cross-process uniformity profile.

Abstract: Multiple input patches are received on an output media, which patches are characterized by print density representing a document processing system's response to different input grayscale values over a potential response space. Values associated with the print density of each input grayscale value are measured. Reference Engine Response Curves are determined from the measured print density values and input gray scale values. A variance data representative of a difference between each measured print density value and a respective reference Engine Response Curve is determined. The variance data is transformed into individual components. Based at least on one selected individual component, a set of calibration compensating Tone Reproduction Curves is determined. The determined calibration compensating Tone Reproduction Curves are applied to input grayscale values.

Abstract: A registration system for use with an imaging device includes sensors for detecting a web speed and a web tension of a moving web and a control system configured to generate a first timing offset for at least one marking station based on the detected web speed and web tension. An image sensor is configured to generate a signal indicative of a position of a marking material applied to the moving web by at least one of the marking stations. The control system is configured to generate a second timing offset for the at least one marking station based on the position of the marking material indicated by the third signal, and to adjust an actuation time for the at least one marking station using the first timing offset and the second timing offset.

Abstract: A method and system for monitoring a print drum maintenance system of an image producing machine is disclosed herein in various embodiments. A test pattern is printed on the print drum, and imaged with an image-on-drum detector to determine a printed pattern response. The print drum is then cleaned again imaged with the image-on-drum detector to determine a cleaned print drum response. A cleaning efficiency is computed by comparing the imaged test pattern response to the imaged cleaned print drum response and determining if a failure condition exists by comparing the computed cleaning efficiency to predetermined limits. A corrective process is performed if the failure condition does exist, the corrective process including changing parameters of the drum maintenance system according to the computed cleaning efficiency. The changed parameters are compared to predetermined thresholds and, if not exceeding the thresholds, the cleaning is repeated after the parameters are changed.

Abstract: Systems and methods are provided for monitoring jets of an image device. The detection is implemented using a data processor that monitors information sent to a jet and using an image sensor that monitors an image being printed or an image after being printed. A detector detects the difference between the image being printed and/or the image after printing to the information sent to the jet, and identifies a faulty jet based on the difference detected.

Abstract: A method of aligning a printhead is described herein. The method includes accelerating a media along a process path, controlling a first printhead to form a first mark upon the accelerating media, detecting the first mark on the accelerating media, comparing a first mark detection data with first printhead desired alignment data, determining a first correction based upon the comparison of the first mark detection data, and modifying an alignment of the first printhead based upon the determined first correction.

Abstract: Xerographic machines can print documents that have unintentional streaking parallel to the process direction. There are many possible source of the streaking. Currently, the streaking is minimized by using a cross process direction dependent modulation, called a profile, to modulate a modulated light beam being scanned across the photoreceptor. The profile is purely a function of cross process direction position. The profile can minimize, and often eliminate, streaking for any one area coverage, but only for that one area coverage. Different profiles can be produced that work best for different area coverages. Choosing a profile from a group of profiles for use with each scan line can minimize parallel streaking for a wider range of area coverages.

Abstract: What is disclosed is a novel system and method for reducing process color banding due to printhead non-uniformities in a direct marking device. In one example, a first measurement of a printhead spatial non-uniformity is obtained along a first line in a color space which produces a spatial uniformity when a target primary color is printed alone. A first spatial tone reproduction curve is generated. A second measurement of the printhead spatial non-uniformity is obtained along a second line in color space in a coverage area of a process color which maximally changes a halftone structure of the target primary color. A second spatial TRC is generated. The first and second spatial TRCs are combined using a weighted average which balances the primary and process colors. A modified spatial TRC is generated. The printhead is adjusted at a location of the target primary color according to the modified spatial TRC.

Abstract: An apparatus prints on a continuous web moving in a process direction. A fiducial marker prints on a portion of the web a repeating pattern of fiducial marks at a predetermined spacing along the process direction. At least two printing stations are operatively disposed downstream of the fiducial marker, each printing station including a printhead for placing marking material suitable for a partial image on the web. A photosensor reads a fiducial mark on the web moving relative to the printing station.

Abstract: A method for processing input document data uses a drop mass history for ink jets in a print head to adjust other document data processing. The method includes ejecting ink in a plurality of patterns onto an image substrate from a plurality of ink jets, each drop in a pattern corresponding to one drop mass history in a plurality of drop mass histories, identifying a relationship between drop masses for the drops in an ejected pattern and a reflectance parameter for the ejected pattern, measuring a reflectance value for each pattern ejected onto the image substrate, and identifying a drop mass value for each drop mass history in the plurality of drop mass histories, each drop mass value being identified from the measured reflectance value for each pattern and the identified relationships between the drop masses and the reflectance parameter for each pattern.