A method for compensating for failed printing nozzles in an inkjet printing machine uses a computer to provide an increased ink drop volume of adjacent nozzles. All existing printing nozzles are measured regarding print failure and deviation of a printed dot beyond a specific threshold, so that the printing nozzles are marked either as functioning, failed, or printing a dot deviating in a direction transverse to the printing direction, and the results are saved on the computer. The computer hides all functioning printing nozzles and marks all remaining isolated printing nozzles as failed nozzles. The computer groups adjacent remaining printing nozzles by marking nozzles printing a dot deviating in a direction transverse to the printing direction as functioning printing nozzles contributing to the compensation or as failed printing nozzles in accordance with a rule, and the computer compensates for all printing nozzles having been marked as failed.

A printing device comprising a printing head including a plurality of nozzles configured to discharge ink to a printing medium are arranged, and a control unit configured to control discharge of the ink. The printing head is configured to discharge the ink along with scanning that is a relative movement in a predetermined direction with respect to the printing medium, and in test printing for printing a TP on the printing medium, the control unit performs control such that the ink of a first discharge amount is discharged from the nozzles when a color difference between the TP and the printing medium is greater than a predetermined threshold value, and the ink of a second discharge amount that is greater than the first discharge amount is discharged when the color difference between the TP and the printing medium is equal to or smaller than the threshold value.

According to one example of the present invention there is provided a method of printing, with a printer, an image on a substrate, the printer comprising a substrate support. The method comprises obtaining an image to be printed, determining an offset position of a substrate positioned on the substrate support relative to a predetermined reference printing position, and controlling the printer to print the image to be printed at the determined offset position.

A printing apparatus includes a printing head provided with a first nozzle row and a second nozzle row arranged shifted from the first nozzle row in a nozzle alignment direction, and a control unit configured to control ejection of ink from nozzles included in the printing head onto a medium based on print data. The control unit is configured to set an image to be complemented as a partial region of an image to be printed on the medium in accordance with a boundary portion between the first nozzle row and the second nozzle row, assign print data for printing the image to be completed to at least one of a first adjacent nozzle that is a nozzle in the first nozzle row and adjacent to the boundary portion and a second adjacent nozzle that is a nozzle in the second nozzle row and adjacent to the boundary portion, and complement the image to be complemented by ink ejection from at least one of the first adjacent nozzle and the second adjacent nozzle.

There is provided a liquid discharge apparatus including: a head having nozzles; a conveyer; and a controller. The controller is configured to carry out a conveyance process of conveying a recording medium in a conveyance direction, and a discharge process of discharging a liquid from the nozzles to the recording medium. The discharge process includes a plurality of discharge steps carried out to a unit area of the recording medium based on data obtained by decomposing an image data into complementary patterns. In at least one of the discharge steps corresponding to the unit area, a function of a discharge duty of the nozzles has an ascending portion or a descending portion. The controller is configured to carry out before the discharge process: a detection process of detecting a defect nozzle in the nozzles; and in a case that the defect nozzle is detected, a change process of changing the function.

A method of controlling a printer is disclosed, the printer including a number of print heads extending across a print zone, and each print head including at least one nozzle array extending in a direction of a print head axis. Each nozzle array comprises a center section of nozzles and side sections of nozzles, wherein the side sections of neighboring nozzle arrays overlap defining an overlap region and the center sections of the nozzle arrays define non-overlap regions. The method includes: printing a test pattern using at least two nozzle arrays, the test pattern comprising an interferential-type pattern printed by the side sections of the nozzle arrays in the overlap region and a reference pattern printed by the center sections of the nozzle arrays in the non-overlap regions; detecting characteristics of the printed test pattern; comparing the characteristics of the printed test pattern in the overlap region and in the non-overlap region; and deriving information concerning the alignment of nozzle arrays from the comparison

In a method and device for ascertaining print data for a print image to be printed, the print data is adapted and/or determined such that the time curve of the ink flow quantity, exhibits no quantity changes or flow rates due to which ink ejection errors might be produced, in particular nozzle failures. The device includes: a communication interface configured to receive the print data; and processing circuitry that ascertains, based on the print data, a time curve of an ink flow quantity of ink that, during the printing of the print image, flows in the print bar and/or is ejected from the one or more nozzles of the print bar; and determine, based on the time curve of the ink flow quantity, whether an ink ejection error will be produced.

A method of operating a printer analyzes a printed test pattern in a low-contrast printing configuration. The method includes forming a printed test pattern having a plurality of rows of negative marks on an image receiving member, each negative mark in the plurality of rows of negative marks being surrounded by ink from at least a portion of the plurality of inkjets. The method further includes generating scanned image data of the test pattern and identifying a plurality of locations in the cross-process direction for the negative marks in at least one row of negative marks in the scanned image data of the test pattern.

An inkjet printhead includes a two-dimensional array of drop ejectors arranged as a plurality of columns, each column including a plurality of banks, and each bank including a plurality of groups that each include a plurality of drop ejectors. The drop ejectors in each group are substantially aligned along a first direction. The groups in each bank are spaced from each other along the first direction and are offset from each other along a second direction. The banks in each column are spaced from each other along the first direction and are offset from each other along the second direction. The columns are offset from each other along the second direction. The two-dimensional array has a width W along the first direction and a length L greater than W along the second direction. Each drop ejector includes a nozzle, an ink inlet, a pressure chamber and an actuator

A liquid ejecting head includes driving elements and electrodes each extending a second direction for ejecting liquid of pressure chambers through nozzles. The driving elements are classified into a first element group and a second element group. The electrodes are arranged along a first direction intersecting the second direction and are classified into a first electrode group electrically connected to the first element group, a second electrode group electrically connected to the second element group and a third electrode group not contribute to the ejecting liquid.