To predict more accurately whether ink dots formed on the surface of paper by two nozzles arranged in a nozzle row and located at positions close to each other overlap. A luminance amount for each unit area surrounding each chart is derived from scanned data obtained by reading results of printing a plurality of charts (two-dot line chart corresponding to a nozzle pair of a nozzle of interest and a neighboring nozzle thereof among the plurality of nozzles) associated with a plurality of nozzles respectively. Then, based on the luminance amount for each unit area, the dot formation state in a dot formation line by the plurality of nozzles is determined.

There are provided a printing system, a method of generating a halftone processing rule, a method of acquiring a characteristic parameter, image processing device and method, a halftone processing rule, a halftone image, a method of manufacturing a printed material, an ink jet printing system, and a program which are capable of reducing an operation load of a user and acquiring a halftone processing rule appropriate for the printing system. A characteristic parameter acquisition chart including a pattern for acquiring characteristic parameters related to characteristics of the printing system is output, and the output characteristic parameter acquisition chart is read by image reading means. The characteristic parameters are acquired by analyzing the read image of the characteristic parameter acquisition chart, and halftone processing rules that define the processing contents of halftone processes used in the printing system are generated based on the acquired characteristic parameters.

The invention relates to a method for detecting a failing ejection unit in an array of ejection units during printing of a digital image with liquid ink in a printer wherein a medium is transported relative to the array. The printed image is captured to density values on print positions of the printed image. The invented method comprises a step of adapting a halftone mask that is used in preparation of the digital image, such that from a variation in the image density around the line shaped defect the exact nozzle number associated with the failing ejection unit can be determined.

A redundantly printed security-enhanced document, printing method and system ensure the meaning of the information imparted by variable indicia printed by redundant printing on the document with removable scratch-off coatings. By printing the variable indicia with multiple colors, redundancy and integrity of the intended indicia is achieved. Additionally, inverted color indicia countermeasures to pinprick attacks are also disclosed. The redundantly printed document, methods and systems enhance the overall appearance of the redundantly printed document, and reduce possible consequences resulting from misprinted variable indicia. The resultant printed process color indicia maintains a grayscale equivalent level of a process color greater than or equal to the measured grayscale equivalent level of the substrate surface plus an additional contrast delta of 15%.

A digital printer and a method of controlling the digital printer having a print head with an array of printing elements and a failure detection system arranged to detect malfunctioning printing elements. When, during printing, a malfunctioning printing element is detected, a switch from the current print strategy to another print strategy is arranged during printing which leaves the number of passes per swatch constant, i.e. the print quality is not affected by the switch.

A printing apparatus includes a head including a plurality of nozzles configured to discharge liquid to a medium, an abnormal nozzle detection unit configured to detect an abnormal nozzle having a discharging defect among the plurality of nozzles, a contact detection unit configured to detect contact between the head and the medium, a suction unit configured to perform an ejection operation of ejecting the liquid from the plurality of nozzles, and a control unit. The control unit executes a suction operation when the abnormal nozzle is detected and the contact between the head and the medium is detected, and the control unit executes a printing of complementing the abnormal nozzle when the abnormal nozzle is detected and the contact between the head and the medium is not detected.

A printing system is disclosed. The printing system includes at least one physical memory device to store nozzle correction logic and one or more processors coupled with at least one physical memory device to execute the nozzle correction logic to receive a uniformity compensated transfer function for each of a plurality of pel forming elements, receive an average missing neighbor transfer function, receive a defective nozzles list including one or more of the plurality of pel forming elements indicated as defective during print production; and perform missing neighbor processing by applying the average missing neighbor transfer function associated with the pel forming element determined to be a neighbor of a defective pel forming element.

A method of printing, the method comprising: monitoring operation of first nozzles of a first nozzle array, and if malfunction of a number of first nozzles of the first nozzle array is detected, setting a number of second nozzles of a second nozzle array to a compensation mode. Monitoring operation of the number of second nozzles in the compensation mode and, in response to detecting that a printing parameter of the number of second nozzles differs from a reference printing parameter, adjusting an operation mode parameter of a subset of second nozzles.

In an example, a printing apparatus includes a controller, wherein the controller may be to compare a historic usage of a first printhead nozzle with a historic usage of a second printhead nozzle which is located on a same printhead as the first nozzle. The controller may be to determine that the historic usage of the first nozzle is higher than the historic usage of the second nozzle, and in response identify a currently operational third printhead nozzle, for which the second nozzle is able to compensate; and turn off the third nozzle, and operate the second nozzle at a higher firing frequency to compensate for the third nozzle.

A controller for an inkjet printing device is configured to predict a remaining time period until a failure of the nozzle on the basis of a time curve of offset measurement values with regard to the offset of the ink droplets ejected by said nozzle. A compensation measure may be introduced promptly, before the actual failure of the nozzle on the basis of the prediction in order to have the effect that the compensation measure takes effect at latest at the point in time of the failure of the nozzle, and thus an interruption of the print quality may be prevented.