Abstract: A controller for operating a print head is described, which controller is designed to shift the activation points in time of the print head for printing of different lines of a print image on a recording medium relative to the line signal points in time, said line signal points in time being dependent on the transport velocity of the recording medium, such that the print head is operated with quantized operating frequencies from a set of predefined quantized operating frequencies. The print quality of the print head may thus be increased.

Abstract: 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.

Abstract: In a device for regenerating a print head of an inkjet printing device, a fluid is applied onto the nozzle plate of the print head. The one or more nozzles of the print head can be subsequently operated with one or more no-ejection pulses to produce the effect that fluid is drawn from the nozzle plate into the one or more nozzles and mixes with the ink in the one or more nozzles that the viscosity of the ink in the one or more nozzles is reduced.

Abstract: A method for cleaning an ink jet imaging device, the ink jet imaging device including a main ink supply channel including an entrance side for supplying ink, a first ink channel including a first pressure chamber fluidly connected to a first nozzle; a first actuator associated with the first pressure chamber, the first ink channel being in fluid connection with the main ink supply channel and defining a first ink path from the entrance side of the main ink supply channel to the first nozzle and having a first length L1; a second ink channel including a second pressure chamber fluidly connected to a second nozzle; and a second actuator associated with the second pressure chamber, the second ink channel being in fluid connection with the main ink supply channel and defining a second ink path from the entrance side of the main ink supply channel to the second nozzle and having a second length L2, wherein L2>L1.

Abstract: The present invention relates to an aqueous pre-treatment liquid for use in ink jet printing, the pre-treatment liquid comprising water and magnesium-disulfamate. Such pre-treatment composition is and yellowing and crystal-free and shows good jetting properties. These properties are retained even when a solid co-solvent is added to the composition for anti-curl improvement. Therefore, the present invention enables providing non-yellowing pre-treatment liquids with good jetting properties and anti-curl behavior.

Abstract: During flipping sheets may fold upon themselves under the influence of gravity. To prevent a sheet stacker is provided with a support device for supporting an inner surface of the sheet during flipping, the support device comprising a plurality of flexible fingers elements of different length, each configured to support a different inner area of the sheet during its flipping motion.

Abstract: During flipping sheets may fold upon themselves under the influence of gravity. To prevent a sheet stacker is provided with a holding device for releasably holding at least a portion of the sheet at least partially during the flipping of the sheet by a sheet flipping device, wherein the holding device is configured for movement of the held portion of the sheet in a first direction perpendicular to the flipping axis.

Abstract: A flatbed printer and a method for a flatbed printer are disclosed. The flatbed printer includes a print controller configured to receive a digital image intended to be printed by the flatbed printer, to receive position information entered by a parameter window of the user interface of the position of the image on the flatbed area, to receive an indication entered by the parameter window that the image has to be positioned on the media piece, to open the parameter window for entry of a set of parameters allowing to define a size of the media piece and a position of the media piece on the flatbed surface, and the image position relative to the media piece, to receive the entered set of parameters, to show the media piece and the image on the flatbed area in the preview window, and, when moving the media piece or the image over the flatbed area in the preview window, the relative position of the image with respect to the media piece is preserved.

Abstract: 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.

Abstract: 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.

Abstract: An arrangement for supplying ink to a print bar with small pressure fluctuations may include an ink reservoir and a damping vessel. The print bar may include at least two print heads and is connected with the ink reservoir via a supply line. Each of the print heads is connected with the damping vessel via at least one damping line. The damping vessel is connected with a discharge line. The end of the damping line ends at a first height in the damping vessel. The end of the discharge line ends at a second height above the first height in the damping vessel. The arrangement may supply ink to the print bar with small gas fraction in the ink.

Abstract: A controller for a print head of an inkjet printing device is described that is configured to generate a virtual timing signal during a printing pause of the printing device, and to use the virtual timing signal for the generation of pre-ejection pulses in order to produce a reliable regeneration of the nozzles of the print head during the printing pause.

Abstract: A method of handling a sheet defect error in a duplex print process, wherein media sheets are successively supplied along a feed path and are moved past a print engine where a first image is printed on a first side of each sheet in a first print pass, the sheets are then returned, via a duplex loop that contains a sheet flipping mechanism, to the feed path upstream of the print engine so that a second image can be printed on a second side of each sheet in a second print pass, the finished sheets being then discharged in a predetermined page sequence, and wherein, when a sheet defect is found a first print pass of a sheet, the defective sheet is diverted into an eject path downstream of the print engine, and a print pass for an immediate successor of the defective sheet is skipped.

Abstract: An aqueous ink composition includes a film-forming retardation additive, which enhances the pigment efficiency in the ink composition. A method for making such an ink and a method of printing with such an ink are also disclosed.

Abstract: In a device and a method for improving the print image uniformity, at least one print image is printed by a printer with at least one print bar that has at least one print head with a plurality of print nozzles. An image detector having a plurality of dot/image detection regions detects at least one value profile of measured inking intensities. A comparator compares the value profile with at least one reference value, and generates correction values dependent thereon.

Abstract: An attachment device for attaching an electronic assembly to a base module (e.g. print head) of a printing device can include a carrier plate of the assembly and a support body of the base module that has a groove into which the carrier plate may be inserted and arrested by means of a latch that engages in a recess of the carrier plate. The attachment device advantageously enables an efficient and reliable attachment of the assembly to the base module.

Abstract: In a method and a device for synchronizing a first printing device with a second component (e.g. second printing device), based on a property of a print image printed by the first printing device, which the property is detected by an optical sensor, a first print image is printed and at least one part of the first print image is detected using the optical sensor to generate a corresponding sensor signal. A virtual sensor signal is determined based on first print data and a known position of the optical sensor. The virtual sensor signal is compared with a curve of the sensor signal and a position signal is generated based on the result of the comparison. A second component is started depending on the position signal.

Abstract: A printing device may include two printers for printing to the front side and the back side of a recording medium. The physical page length of at least one print image applied onto the front side of the recording medium is determined. The required page length of at least one print image to be applied onto the back side of the recording medium is adapted to the determined page length. At least one print line of the print image for the back side is printed repeatedly if the required page length for application of the rear print page onto the back side of the recording medium is smaller than the determined page length.

Abstract: In a method and a printing device for influencing an optical property of a varnish layer to be applied onto a printed recording medium, a coating substance is applied onto the recording medium by digital printing before the printing of at least one color separation of the print image on said recording medium. The quantity of the coating substance applied per area unit may be adjusted depending on the desired optical property of the varnish layer to be applied later.

Abstract: A fixation unit for use in a printing apparatus includes a substantially closed box for enclosing a heated space, the substantially closed box including an entry opening and an exit opening for enabling transport of a print substrate through the substantially closed box, a heating element arranged for heating the heated space enclosed by the substantially closed box, and a transport mechanism for engaging a sheet of the print substrate from the entry opening to the exit opening of the substantially closed box. The transport mechanism includes a nip of two belts that are pressed together and run concurrently and in the same direction, the belts being impermeable to any ink component. A printer includes such a fixation unit and a printing method uses such a fixation unit.