Abstract: Systems and methods are provided for compensating for streak defects in images formed by an image forming device, such as a digital printer. The systems and methods include using both modulation of a raster output scanner (ROS actuation) and spatially varying tone reproduction curve (STRC actuation) in a common control system for improving streak correction. Low spatial frequency large amplitude streak defects are corrected using ROS actuation and high spatial frequency streak defects, as well as any residual low frequency defects, are corrected using STRC actuation.

Abstract: A method for calibrating in situ a plurality of printheads in an imaging device has been developed. Firing signals operate a plurality of printheads to form ink test patterns on an image receiving member. Reflectance measurements of light reflected from the test patterns and optical density measurements for a portion of the patterns formed by only one printhead in the plurality of printheads are used to adjust the firing signals and enable the printheads to print within a predetermined range about an average reflectance value and a predetermined optical density.

Abstract: A method for operating a web printing system enables web and roller changes arising from temperature changes to be identified and used to adjust operation of the reflex registration system. The method includes identifying a temperature change for at least one roller in a web printing system, identifying a temperature change for a web moving through the web printing system at one or more locations in the web printing system, modifying web velocity computations for a reflex registration system with reference to the identified temperature change for the at least one roller and the identified temperature change for the web, and operating printheads to eject ink onto the web at positions identified with reference to the modified web velocity computations.

Abstract: A method of operating a printer enables compensation parameters to be generated and stored in association with system conditions detected at the time of the compensation parameter generation. Upon detection of corresponding system conditions at a later time, the printer is able to use the previously generated and stored compensation parameters to adjust the timing of printhead ejections to improve the registration in ink images formed by the system.

Abstract: A method for calibrating in situ a plurality of printheads in an imaging device has been developed. Firing signals operate a plurality of printheads to form ink test patterns on an image receiving member. Reflectance measurements of light reflected from the test patterns and optical density measurements for a portion of the patterns formed by only one printhead in the plurality of printheads are used to adjust the firing signals and enable the printheads to print within a predetermined range about an average reflectance value and a predetermined optical density.

Abstract: A method enables changes in the operation of a web printing system in response to web dimensional changes being detected. The method includes identifying a cross-process dimensional change in a web moving through a printing system, comparing the identified cross-process dimensional change to a predetermined threshold, and changing operation of a component in the web printing system in response to the cross-process dimensional change exceeding the predetermined threshold.

Abstract: A method for calibrating in situ a plurality of printheads in an imaging device has been developed. Firing signals operate a plurality of printheads to form ink test patterns on an image receiving member. Reflectance measurements of light reflected from the test patterns and optical density measurements for a portion of the patterns formed by only one printhead in the plurality of printheads are used to adjust the firing signals and enable the printheads to print within a predetermined range about an average reflectance value and a predetermined optical density.

Abstract: A method enables a printing system to be operated in one of two registration control modes. The method includes operating at least one marking station with reference to a first velocity measurement of a web moving along a web path in response to a first registration control mode being active, the first velocity measurement corresponding to an angular velocity signal obtained from only a first roller in a web path, and operating the at least one marking station with reference to a second velocity measurement of the web moving along the web path in response to a second registration control mode being active, the second velocity measurement corresponding to at least two angular velocity signals obtained from at least the first roller and a second roller in the web path.

Abstract: A computer-implemented method for performing color registration on template media having template markings thereon.

Abstract: A method of operating a printer enables printheads mounted on print bars to be operated to compensate for misalignment of printheads in the process direction. The method includes identifying a position in the process direction for each printhead in a plurality of printheads, selecting one of the identified printhead positions as a reference printhead position, identifying a printhead timing parameter for each printhead mounted to at least one print bar, generating a firing signal for the printheads mounted to the at least one print bar, and adjusting delivery of the firing signal by the identified printhead timing parameter for each corresponding printhead mounted to the at least one print bar to coordinate actuation of inkjet ejectors in the printheads mounted to the at least one print bar and compensate for misalignment of the printheads in the process direction.

Abstract: A method for operating a web printing system enables web and roller changes arising from temperature changes to be identified and used to adjust operation of the reflex registration system. The method includes identifying a temperature change for at least one roller in a web printing system, identifying a temperature change for a web moving through the web printing system at one or more locations in the web printing system, modifying web velocity computations for a reflex registration system with reference to the identified temperature change for the at least one roller and the identified temperature change for the web, and operating printheads to eject ink onto the web at positions identified with reference to the modified web velocity computations.

Abstract: A method enables a controller to align printheads in a printer. The method includes identifying a first cross-process position for each printhead in a plurality of printheads in a printer with reference to image data of a test pattern printed by the plurality of printheads on a media substrate, identifying a second cross-process position for each printhead in the plurality of printheads, calculating a printhead cross-process position error between the identified first cross-process position and the identified second cross-process position for each printhead, comparing a maximum printhead cross-process position error to a predetermined threshold, and operating a plurality of actuators with reference to the calculated printhead cross-process position errors to reposition the printheads in the plurality of printheads in response to the maximum printhead cross-process position error being equal to or less than the predetermined threshold.

Abstract: A method for operating a web printing system enables web and roller changes arising from temperature changes to be identified and used to adjust operation of the reflex registration system. The method includes identifying a temperature change for at least one roller in a web printing system, identifying a temperature change for a web moving through the web printing system at one or more locations in the web printing system, modifying web velocity computations for a reflex registration system with reference to the identified temperature change for the at least one roller and the identified temperature change for the web, and operating printheads to eject ink onto the web at positions identified with reference to the modified web velocity computations.

Abstract: A method of measuring and correcting the Young's Modulus inline to eliminate its impact on image length variation during print runtime. The method includes intentionally perturbing the nominal operating condition of the web printing system which is controlled by the double reflex printing controller. The perturbation creates misregistration in a control target printed image that is detectable by in-situ sensors, from which Young's Modulus is estimated. Specifically, the web tension before the print zone is set differently from the web tension in the print zone to create misregistration. The error is detected by the inline sensors, and it is used to calculate the actual Young's Modulus. The implementation of the method consists of measuring the Young's Modulus at various frequencies. The correct Young's Modulus in then incorporated into the double reflex printing algorithm.

Abstract: A method of operating a printer enables compensation parameters to be generated and stored in association with system conditions detected at the time of the compensation parameter generation. Upon detection of corresponding system conditions at a later time, the printer is able to use the previously generated and stored compensation parameters to adjust the timing of printhead ejections to improve the registration in ink images formed by the system.

Abstract: A method compensates for thermal expansion of rollers in a web print zone. The method includes receiving an angular velocity signal from a first encoder for a roller in a print zone of a moving web printing system, receiving a signal from a first temperature sensor corresponding to a temperature of the roller, modifying a first diameter for the first roller with a first predetermined distance in response to the temperature of the first roller being different than a first predetermined temperature, identifying a velocity of a moving web in the print zone of the moving web printing system with reference to the modified first diameter, and delivering a firing signal to a first printhead proximate the first roller to energize the inkjet nozzles in the first printhead and eject ink onto the web at a position corresponding to the identified moving web velocity.

Abstract: Methods and systems are provided to increase or optimize the illumination used with a sensor to measure printed ink colors on a substrate at high speed (up to 3 m/s) and high resolution. By modifying the number of light sources, their wavelengths and/or their relative intensities, the optical contrast can be increased or optimized to yield a higher signal-to-noise ratio and improved accuracy for the measurement of multiple colors. In one implementation, multiple LEDs with selected output peak wavelength may be used to achieve higher contrast imaging for each color.

Abstract: A method enables a controller to align printheads in a printer. The method includes identifying a first cross-process position for each printhead in a plurality of printheads in a printer with reference to image data of a test pattern printed by the plurality of printheads on a media substrate, identifying a second cross-process position for each printhead in the plurality of printheads, calculating a printhead cross-process position error between the identified first cross-process position and the identified second cross-process position for each printhead, comparing a maximum printhead cross-process position error to a predetermined threshold, and operating a plurality of actuators with reference to the calculated printhead cross-process position errors to reposition the printheads in the plurality of printheads in response to the maximum printhead cross-process position error being equal to or less than the predetermined threshold.

Abstract: A method of operating a printer enables printheads mounted on print bars to be operated to compensate for misalignment of printheads in the process direction. The method includes identifying a position in the process direction for each printhead in a plurality of printheads, selecting one of the identified printhead positions as a reference printhead position, identifying a printhead timing parameter for each printhead mounted to at least one print bar, generating a firing signal for the printheads mounted to the at least one print bar, and adjusting delivery of the firing signal by the identified printhead timing parameter for each corresponding printhead mounted to the at least one print bar to coordinate actuation of inkjet ejectors in the printheads mounted to the at least one print bar and compensate for misalignment of the printheads in the process direction.

Abstract: A method enables a printing system to be operated in one of two registration control modes. The method includes operating at least one marking station with reference to a first velocity measurement of a web moving along a web path in response to a first registration control mode being active, the first velocity measurement corresponding to an angular velocity signal obtained from only a first roller in a web path, and operating the at least one marking station with reference to a second velocity measurement of the web moving along the web path in response to a second registration control mode being active, the second velocity measurement corresponding to at least two angular velocity signals obtained from at least the first roller and a second roller in the web path.