The width by which the first, second heads overlap each other cross-sectionally along the first direction is greater than the width by which the fifth, sixth heads overlap each other cross-sectionally along the first direction.

In some examples, a system detects an error in an printing device, and selects a combination of a medium advance error correction process to address a medium advance error and a faulty nozzle correction process to address a faulty nozzle, where the selecting of the combination is from a plurality of different combinations of the medium advance error correction process and the faulty nozzle correction process, and the selecting is based on a criterion relating to an interaction between the medium advance error and faulty nozzle correction processes.

A printing method for performing printing while complementing black with composite black, the printing method including: printing a test pattern having a plurality of patch images for which composite mode varies, this test pattern being printed for each dot size of the black to be complemented; causing a user to select a desired patch image from among the plurality of the patch images included in the printed test pattern, the selection being made for each of the dot size of the black ink to be complemented; and performing printing while complementing the black to be complemented with the composite black generated on a basis of the composite mode corresponding to the desired patch image selected correspondingly to the dot size of the black ink to be complemented.

The disclosed embodiments include a method to compensate for defective printer nozzles. The method can include detecting a defective printer nozzle and initiating a print job including image data of the defective printer nozzle for a pixel location of an image. The image is to be printed in accordance with a print mask that maps printer nozzles to pixel locations of the image. The method can include modifying the image to print the image data in a neighboring pixel location relative to the pixel location of the image and printing the modified image.

Disclosed is an industrial single-pass inkjet printer/press incorporating a line-scan camera. The line-scan camera enables system software to inspect every sheet for quality assurance purposes. These inspection results are tied back to a digital printer to take one or more of several possible actions. Actions include ensuring a particular number of acceptable prints are generated and sorted. Actions further include performing nozzle checks without pausing or interrupting production orders.

Print data is organized over rows and columns. The columns of each row are selectively assigned to calibration tables respectively corresponding to printheads of a pagewide array in accordance with a substrate advancement skew relative to the pagewide array. The calibration tables are applied to the columns of each row respectively assigned to the calibration tables. The columns of each row to which the calibration tables have been applied are printed using the printheads respectively corresponding to the calibration tables.

A liquid discharge apparatus includes circuitry and a memory. The circuitry generates density correction data corresponding to a reference printing condition, based on reference measurement data on a measurement result of a patch pattern printed under the reference printing condition, to control an image density. The memory stores difference data on a difference between measurement data of one or more printing conditions different from the reference printing condition and the reference measurement data. The circuitry generates density correction data corresponding to the one or more printing conditions different from the reference printing condition, based on the reference measurement data and the difference data stored in the memory.

An ink-jet recording apparatus includes a recording unit, a scanning unit, an acquisition unit, and a determination unit. In the recording unit, a plurality of nozzles to apply ink is arrayed. The scanning unit is configured to perform relative scanning with the recording unit on a recording medium. The acquisition unit is configured to acquire input image data that includes a bar code including a plurality of black bars and a plurality of white bars and having a length in a first direction that is greater than a length in a second direction crossing the first direction. The determination unit is configured to determine, based on lengths of the plurality of white bars in the second direction, an amount of ink to be applied to a black bar adjacent to a corresponding white bar in the second direction.

A liquid ejection apparatus is provided that includes a plurality of liquid ejection head units that are configured to eject liquid onto a conveyed object being conveyed; a detection unit that is provided with respect to each liquid ejection head unit of the plurality of liquid ejection head units and is configured to output a detection result indicating at least one of a position, a moving speed, and an amount of movement of the conveyed object with respect to a conveying direction of the conveyed object; and a control unit configured to control each liquid ejection head unit among the plurality of liquid ejection head units to eject liquid at a timing based on a plurality of the detection results of a plurality of the detection units.

An example of a printing system is disclosed. The example disclosed herein comprises a plurality of nozzles and a controller. The plurality of nozzles is to eject a printing agent on a substrate to print a print job. The controller is to receive the print job comprising an outline and a fill area to be printed. The controller is also to define a first subset of the plurality of nozzles as a first printing mode to print the outline. The controller is further to define a second subset of the plurality of nozzles as a second printing mode to print the fill area, wherein the second subset comprises more nozzles than the first subset. The controller is further to print the print job based on the first printing mode and the second printing mode.