Abstract: A printing device comprises a print head, imaging member, and a moveable sensor array. The print head is configured to deliver marking material to the imaging member as it moves in a process direction. The linear sensor array comprises a plurality of photo sensors configured to scan the imaging member. The photo detectors of the linear sensor array define a sensor axis that is substantially perpendicular to the process direction. The linear sensor array is configured to move along the sensor axis between a first position where the sensor array scans one portion of the imaging member and a second position where the sensor array scans another portion of the imaging member. If a fault is detected during calibration of the sensor array, the moveable sensor array may be used to determine whether the source of the fault rests with the imaging member or the sensor array.

Abstract: A printing apparatus has a substantially shiny photoreceptor imaging surface, and a photosensor array disposed to receive specularly-reflected light from the imaging surface. A quantity of toner is placed on the imaging surface, and data is derived based on light reflected from the imaging surface. The reflected light is filtered to a color effectively complementary to the toner color. The system avoids noise caused by diffusely-reflected light from powdered toner.

Abstract: Systems and methods are provided for calibrating a sensory array to ensure a robust cross-process registration measurement. The calibration is implemented using a calibration step that determines the signature error amount of a given image reading sensor. The signature error amount for the sensor is stored in a signature error look-up table. When the sensors are used to sense print head alignment, the correction may be implemented by accessing the signature error look-up table for the given sensor when calibrating the print heads. The signature error look-up table provides an amount of offset for each sensor that is used in determining the appropriate head position of a given print head to calibrate the print heads for the signature error associated with the given sensor.

Abstract: Systems and methods are provided for detecting intermittent, weak or missing jets of a printer. The detection is implemented using a test pattern. Detected failed jets may be confirmed using a verification target. A printhead containing nozzles corresponding to detected failed jets may be wiped or purged.

Abstract: Systems and methods are provided for calibrating a sensory array to ensure a robust cross-process registration measurement. The calibration is implemented using a calibration step that determines the signature error amount of a given image reading sensor. The signature error amount for the sensor is stored in a signature error look-up table. When the sensors are used to sense print head alignment, the correction may be implemented by accessing the signature error look-up table for the given sensor when calibrating the print heads. The signature error look-up table provides an amount of offset for each sensor that is used in determining the appropriate head position of a given print head to calibrate the print heads for the signature error associated with the given sensor.

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: 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 printing device comprises a print head, imaging member, and a moveable sensor array. The print head is configured to deliver marking material to the imaging member as it moves in a process direction. The linear sensor array comprises a plurality of photo sensors configured to scan the imaging member. The photo detectors of the linear sensor array define a sensor axis that is substantially perpendicular to the process direction. The linear sensor array is configured to move along the sensor axis between a first position where the sensor array scans one portion of the imaging member and a second position where the sensor array scans another portion of the imaging member. If a fault is detected during calibration of the sensor array, the moveable sensor array may be used to determine whether the source of the fault rests with the imaging member or the sensor array.

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: This invention relates to a method for the calibration of linear array photo sensors operating in a specular reflection mode. Errors may be introduced when a highly diffused image is measured by the linear array photosensor that was calibrated in a specular mode. These errors result in artifacts such as streaks in the captured image. The method measures non-uniformity errors using a highly diffuse white reflective surface, and then applies an appropriate scaled pixel-wise correction factor to the image when the sensor is used in the specular mode.

Abstract: A method for detecting a defect in an inkjet print head for printing a substantially clear ink includes including an ultraviolet or infrared sensitive material in the substantially clear ink, marking a test image on a substrate by jetting the substantially clear ink through one or more jets of the inkjet print head to be evaluated, exposing the test image to activating radiation having a wavelength to which the included ultraviolet or infrared sensitive material responds. During or following the exposing, the test image is evaluated with an image sensor, and whether the inkjet print head or any one of the one or more jets thereof being evaluated is defective is then determined based on the evaluation. A system for the method is also set forth.

Abstract: A method for detecting a defect in an inkjet print head for printing a substantially clear ink includes including an ultraviolet or infrared sensitive material in the substantially clear ink, marking a test image on a substrate by jetting the substantially clear ink through one or more jets of the inkjet print head to be evaluated, exposing the test image to activating radiation having a wavelength to which the included ultraviolet or infrared sensitive material responds. During or following the exposing, the test image is evaluated with an image sensor, and whether the inkjet print head or any one of the one or more jets thereof being evaluated is defective is then determined based on the evaluation. A system for the method is also set forth.

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: 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: This invention relates to a method for the calibration of linear array photo sensors operating in a specular reflection mode. Errors may be introduced when a highly diffused image is measured by the linear array photosensor that was calibrated in a specular mode. These errors result in artifacts such as streaks in the captured image. The method measures non-uniformity errors using a highly diffuse white reflective surface, and then applies an appropriate scaled pixel-wise correction factor to the image when the sensor is used in the specular mode.

Abstract: A lead edge and/or trail edge sheet curl sensing and constraint method and system. First and second light emitters and detector pairs are aligned such that the light beams from the first light emitter and second light emitter cross at the transport media sheet substrate path, which constitutes the path of a media sheet substrate with zero curl. A media sheet substrate with either positive or negative curl on the lead edge of the sheet substrate interrupts light beams from the first and second light emitters, as detected by first and second light detectors. A similar approach can be used to detect the trail edge curl. The time delay between the light beam interruptions is proportional to the sheet substrate curl, and the order of interruptions indicates whether the sheet substrate curl is positive or negative. A first pair and a second pair of substrate constraint rollers can also be provided in the paper path upstream and downstream of the sensing system.

Abstract: A lead edge sheet curl sensor apparatus and method are disclosed. In general, a first and a second light emitter are aligned wherein the light beams from the first light emitter and second light emitter cross. The first and second light emitter beams cross at the transport media sheet substrate path wherein the transport media sheet substrate path is the path of a media sheet substrate with zero curl. First and second light detectors are aligned to receive the light beams from the first and second light emitters. A media sheet substrate with either positive or negative curl on the lead edge of the sheet substrate interrupts light beams from first and second light emitters, as detected at first and second light detectors. The time delay between the light beam interruptions is proportional to the sheet substrate curl, and the order of interruptions indicates whether the sheet substrate curl is positive or negative.

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 printing apparatus has a substantially shiny photoreceptor imaging surface, and a photosensor array disposed to receive specularly-reflected light from the imaging surface. A quantity of toner is placed on the imaging surface, and data is derived based on light reflected from the imaging surface. The reflected light is filtered to a color effectively complementary to the toner color. The system avoids noise caused by diffusely-reflected light from powdered toner.

Abstract: Systems and methods are provided for detecting intermittent, weak or missing jets of a printer. The detection is implemented using a test pattern. Detected failed jets may be confirmed using a verification target. A printhead containing nozzles corresponding to detected failed jets may be wiped or purged.