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 test pattern is written using multiple image beams in a non image zone at set time intervals. The test pattern is sensed and a profile of each beam is determined from the multiple image beams. A minimum reflectance of the profile is determined from the test pattern of each beam thereby providing an exposure of each respective beam. A centroid of a profile is determined from the test pattern of each beam thereby providing a position of each respective beam. At least one of the following is then determined: frequency, amplitude and phase of banding, which is inherent in a printing device, based on the sensed test pattern. A plurality of groups of image beams intensity changes is combined wherein each group is separated by a set displacement. A banding profile is determined from the group beam intensities. At least one banding compensation metric is determined based at least on one of the determined frequency, amplitude and phase of banding. Beam intensity changes are adjusted based on the determined banding compensation metric to compensate the banding inherent in the printing device.
Abstract:
Systems and methods are provided for determining registration errors in the cross process direction of a printer. A first straight line is obtained by detecting line centers of a first plurality of dashes in a test pattern. A second straight line is obtained by detecting a line center positions of a second plurality of dashes in the test pattern. A difference between the off-set of the first straight line and the off-set of the second straight line is used in determining registration errors.
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.
Abstract:
A system that extends the operational effectiveness of an image reproduction machine without requiring downtime for service by personnel includes a detection subsystem that monitors components of an image reproduction system for detecting a banding defect in the image reproduction system and an automated compensation subsystem for modifying operation of the image reproduction system to compensate for the detected banding defect so that the image reproduction system continues to generate images at an acceptable quality level. The automated compensation subsystem adjusts components and/or data used by image reproduction system to compensate for the identified banding defect without requiring immediate operator or service personnel intervention. This compensation may successfully attenuate the banding defect so that the image reproduction system continues to produce acceptable images without downtime while awaiting service by personnel. The system may also include a diagnostic subsystem for determining causes for a detected banding defect to further enhance the operation of the compensation system or to facilitate a repair action by a person.
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:
Systems and methods are provided for determining registration errors in the cross process direction of a printer. A first straight line is obtained by detecting line centers of a first plurality of dashes in a test pattern. A second straight line is obtained by detecting a line center positions of a second plurality of dashes in the test pattern. A difference between the off-set of the first straight line and the off-set of the second straight line is used in determining registration errors.
Abstract:
Systems and methods provide calibration for a linear array sensor. A test pattern having a plurality of lines is used. Comparison between expected and measured spacing between a pair of neighboring lines is used to determine sensor position displacement.
Abstract:
A document reproduction machine having an optical component which is coated with a low surface energy transparent coating to reduce the adhesion of particles on the optical component. During the forming of the coating the lateral conductivity of the coating is modified so as to dissipate electrical charge build up on the coating.