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 register images printed by two printers accurately. The method includes operating at least one marking station in a first printer with reference to a low frequency component and a high frequency of a velocity measurement for a web in the first printer, printing fiducial marks on the web with a marking station in the first printer, detecting the fiducial marks with a fiducial mark sensor in a second printer, generating a velocity measurement for the web as the web moves along a web path in the second printer that corresponds with the detected fiducial marks, and operating at least one marking station in the second printer with reference to a low frequency component and a high frequency component of the velocity measurement of the web moving along a web path in the second printer.

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 printer includes a plurality of a plurality of printheads and a plurality of rolls positioned opposite the printheads along a media path in the printer. Print media contact and move over the rolls as the printheads eject ink onto the print media moving along the media path. A controller is configured to generate a signal to operate a printhead with reference to an angular position of a roll positioned opposite to the printhead that receives the signal to compensate for flight time errors due to backer roll eccentricity.

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 for adjusting tension to a media web in a printing system includes identifying a tension level between the media web and at least one roll that is in contact with the media web. The tension level is identified with reference to a slip condition between the media web and the at least one roll. The identified tension is stored in a memory in the printing system.

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 for compensating a charge retentive imaging surface for a photoreceptor in a toner image processing machine, the surface including a plurality of panels, each panel including a document printing zone (DPZ) and an interdocument zone (IDZ), and the machine including at least one specially programmed computer, at least one sensor, and charging members for charging the surface, including: measuring for each panel, using the sensor, first density values for a plurality of points in the DPZ, the DPZ in a printing region of the photoreceptor; measuring for each panel, using the sensor, a second density value for the IDZ; determining for each IDZ, using a processor in the computer, a respective compensated IDZ density value; and modifying operation of the charging members according to the compensated IDZ density values, such that the first density values for each panel are substantially centered with a desired density value.

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 runout errors in a web printing system. The method includes identifying runout error at a first roller driving a web of printable media, generating a runout compensation value corresponding to the identified runout error, identifying a velocity of the moving web with reference to encoder output corresponding to an angular velocity of the first roller and the generated runout compensation value, and delivering a firing signal to a print head proximate the first roller to energize the inkjet nozzles in the print head and eject ink onto the web at a position corresponding to the computed web velocity.

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: A fusing apparatus includes a fuser roll and a pressure roll which define a nip therebetween. An internal heat source is disposed within a interior of the fuser roll. An external heat source is disposed adjacent the fuser roll for heating an outer surface of the fuser roll. One or both of the internal heat source and the external heat source is controlled during a print job such that the thermal gradient across the fuser roll is adjusted. As a result, a temperature overshoot which generally occurs after the print job is finished can be reduced. The influence of subsequent jobs on the fuser roll surface temperature can also be accommodated.

Abstract: A method enables a printing system to register images printed by two printers accurately. The method includes operating at least one marking station in a first printer with reference to a low frequency component and a high frequency of a velocity measurement for a web in the first printer, printing fiducial marks on the web with a marking station in the first printer, detecting the fiducial marks with a fiducial mark sensor in a second printer, generating a velocity measurement for the web as the web moves along a web path in the second printer that corresponds with the detected fiducial marks, and operating at least one marking station in the second printer with reference to a low frequency component and a high frequency component of the velocity measurement of the web moving along a web path in the second printer.

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 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 system suited to scheduling print jobs for a printing system includes a first processing component which identifies preliminary attributes of print jobs to be printed on sheets. A job scheduler receives the preliminary attributes and assigns each of the print jobs to one of a plurality of job queues in time order for printing. Print jobs spanning the same time are scheduled for printing contemporaneously. In one mode of operation, the assignment of the print jobs to the job queues is based on their preliminary attributes and on the application of at least one constraint which affects contemporaneous printing of at least two of the plurality of print jobs. A second processing component identifies detailed attributes of the print jobs. A sheet scheduler receives information on the assignments of the print jobs and their detailed attributes and forms an itinerary for each sheet to be printed.

Abstract: According to aspects of the embodiments, there is provided methods and systems that incorporate a model predictive controller (MPC) in an image reproduction machine with known disturbance information. The MPC uses the control action at a current time in order to minimize the impact of an impending disturbance as well as to maximize current control performance. The impending disturbance is used by the MPC to determine an incremental change that combines steady state and transient state impact on the image reproduction machine. Disturbance such as print media type, image content type, physical dimension of the print media, weight of the print media, and print job data can be employed. Further, control of the image reproduction machine is generated in real time over a receding horizon, for the purpose of minimizing a cost function indicative of image variation, energy consumption, or the like.

Abstract: A method enables linear web velocities generated with reference to angular velocity signals generated by encoders at different rollers in a double reflex printing registration system to be equalized. The method includes identifying a low frequency component of a first linear velocity of a moving web, identifying a high frequency component of a second linear velocity of the moving web, and computing a linear velocity for the moving web at a roller in a print zone with reference to the identified high frequency component of the second linear velocity and the identified low frequency component of the first linear velocity.

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.