A printer comprises a print carriage, a line sensor, a processor and a controller. The print carriage is configured to print a calibration plot onto print media. The line sensor is configured to emit light onto the calibration plot across the width of the calibration plot and measure the intensity of light reflected from the calibration plot. The processor is configured to determine a correction factor according to a position of a peak in the measured intensity corresponding to a position in the printed calibration plot in which a portion of a first printed mark overlaps a portion of a second printed mark. The controller is configured to adjust the distance by which print media is advanced according to the correction factor. A method for automatically calibrating the advance of print media in a printer comprises printing a calibration plot onto print media, scanning the printed media with a line sensor, determining a correction factor based on a signal from the sensor indicating light intensity across a width of the printed calibration plot and adjusting the advance based on the correction factor.

The present disclosure relates to methods and devices for performing print control. In an example there is disclosed a control method. The control method may comprise programming a print mask to instruct printhead nozzles on a moveable carriage to deposit a first line of print material on a medium, wherein the print mask controls the depositing so that an edge of an area of the medium on which material is deposited defines a pattern which is repeated along a scan axis of the carriage and which differs in a direction of movement of the medium. The control method may further comprise scanning the first line of print material. The control method may further comprise performing control of subsequent print material depositing or medium advancement, based on the scan.

Provided are an inspection method, a program, an inspection device, and a printing device capable of realizing a uniform inspection in a defect inspection of a printed article using a special substrate. A method includes an imaging data acquisition step (S14) of acquiring imaging data (48) of a printed article using a special substrate, a non-printing region positional information acquisition step (S16) of acquiring information (44) for specifying a position of a non-printing region in the imaging data, the non-printing region corresponding to a substrate region of the printed article on which a pattern and a background of the pattern are not printed, an inspection step (S20) of specifying the non-printing region, analyzing the imaging data by applying a predetermined inspection rule (46), and performing an inspection of the printed article, and a notification step (S22) of performing a notification of an inspection result (50) and not performing a notification of an inspection result indicating that a defect is present in the substrate region of the printed article corresponding to the non-printing region.

A method for determining print defects in a printing operation carried out on an inkjet printing machine for processing a print job includes using a camera system to record and digitize printed products generated during the printing operation, feeding the camera image having been thus generated to a detection algorithm on the computer, alerting a machine control unit when print defects are found, and ejecting the printed product through a waste ejector if necessary. The detection algorithm separates color separations of the camera images, detects the print defects in the color separations, links images of the individual color separations to form a candidate image, filters the candidate image, enters the remaining detected print defects into a list, and forwards the list to the machine control unit of the printing machine.

A method of printing improved printed products using defect-free printing machine nozzles and compensated defective nozzles includes printing products and a test chart with test fields onto a transported substrate, the test fields having tonal values, every test field including an unprinted line from a nonactivated, nonprinting nozzle compensated by a neighboring nozzle having a compensation value, pairs of tonal value and compensation value being specified and used for the chart, recording an image of the chart, computer-analyzing the image and determining the compensation value. Every pair of tonal value and compensation value is used multiple times in the chart and a corresponding number of spaced apart test fields is created. A characteristic value representing test field homogeneity and determining compensation value quality is assigned to every measuring field. The best characteristic value regarding a specified criterion and the compensation value is determined for every tonal value.

A print medium having a calibration pattern printed thereon for generating alignment data for a printhead. The calibration pattern contains rows of spaced apart fiducials, each fiducial having a plurality of concentric shapes representing a Barker code.

A method for correcting in-track position errors in a digital printing system includes determining a non-linear in-track position correction function responsive to measured in-track position errors, wherein the in-track position corrections are quantized to integer in-track position corrections. A representation of the in-track position correction function is stored in a digital memory, wherein the representation of the in-track position correction function includes the cross-track positions and transition direction of transitions in the in-track position correction function. Digital image data for a digital image to be printed is received, and corrected image lines are determined by resampling the digital image data responsive to the stored representation of the in-track position correction function. The corrected image lines are modified to provide anti-aliasing pixels at cross-track positions adjacent to transitions in the in-track position correction function.

Systems and methods are provided for. One embodiment is a system that includes an interface configured to receive an image of media printed on with print data, and memory configured to store defect reference data of nozzles belonging to printheads of a printer. The system also includes a print defect controller configured to detect a nozzle defect in the image based on a comparison of the image with the print data, and to determine a type of the nozzle defect based on a comparison of the nozzle defect with the defect reference data.

A liquid droplet ejecting apparatus comprises a liquid droplet ejecting head which has a nozzle array composed of a plurality of nozzles arranged in a first direction, a relative movement mechanism which relatively moves the liquid droplet ejecting head and a recording medium in the first direction, and a controller. The controller controls the liquid droplet ejecting head and the relative movement mechanism to record, on the recording medium, a nonuniformity correction pattern in order to correct any dispersion in a liquid droplet ejection amount among the plurality of nozzles. The controller is configured, in order to record the nonuniformity correction pattern, such that the liquid droplet ejecting head is allowed to eject liquid droplets from at least the first nozzle to thereby record a first pattern group, the relative movement mechanism is allowed to relatively move the liquid droplet ejecting head and the recording medium in the first direction by a predetermined distance, and the liquid droplet ejecting head is allowed to eject the liquid droplets from at least the second nozzle to thereby record a second pattern group.

A system for aligning print-heads in a printing-press, which includes a print-head array which includes a plurality of print-head-rows. Each print-head-row includes a plurality of print-heads and prints print a color associated with therewith. Each print-head includes an array-of-nozzles, which includes a plurality of nozzle-lines. The system includes an imager and a processor. The imager includes at least one imaging-sensor. The imager is configured to acquire an image of a printed first-alignment-pattern and further configured to acquire an image of a printed second-alignment-pattern. The processor is configured to receive the image of the first-alignment-pattern and the image of the second-alignment-pattern and to determine alignment of reference print-heads in at least a reference-row of print-heads from the image of the first-alignment-pattern. The processor is also configured to determine alignment of color print-heads in rows other than the reference-row of print-heads, relative to the reference print-heads, from the image of the second-alignment-pattern.