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 device may be configured to check, via evaluation of resistance data of a cleaning sensor arranged on a print bar of an inkjet printing device, whether a cleaner for cleaning the one or more print heads of the print bar exhibits a negative effect. The state of a cleaner may be reliably and efficiently monitored via the installation of a cleaning sensor in a print bar.

Abstract: 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.

Abstract: In a method and system for increasing print quality, activation pulses are activated with which a nozzle of an inkjet printing device to print dots on a recording medium. The activation pulses may be adapted based on sensor data with respect to already printed dots. The method and system can further include an automatic adaptation of the activation pulses to increase print quality even given the presence of soiling at the nozzle.

Abstract: In a method for adjusting a setup for an encoder for printing to a recording medium of unknown thickness with a multi-row inkjet print head in a printing system, a continuous test line is printed onto the recording medium, transversal to a feed direction of said recording medium, a varied width of the test line is measured, and the adjustment of the setup is modified to minimize the width of the test line.

Abstract: An ink supply system for a print bar of an inkjet printing device includes two supply lines that travel along the longitudinal axis of the print bar and direct ink with opposite flow direction. The print heads of the print bar are respectively connected to both supply lines via a connecting line in order to supply ink to said print heads. A uniform mean hydraulic pressure is produced in all print heads via the opposite flow directions in the two supply lines.

Abstract: In order to determine the nip between a print head and a printing substrate in an ink printing apparatus, ink droplets of a first and second size are simultaneously fired toward the printing substrate by different nozzles of a nozzle row of the print head given a predetermined feed velocity of the printing substrate, whereby print dots of a first size are generated on the printing substrate in a first two print dot row and print dots of a second size are generated on the printing substrate in a second two print dot row. The clearance of the first two print dot row from the second two print dot row is subsequently measured, and the size of the nip is determined from the measured clearance.

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: In a method for adjusting a setup for an encoder for printing to a recording medium of unknown thickness with a multi-row inkjet print head in a printing system, a continuous test line is printed onto the recording medium, transversal to a feed direction of said recording medium, a varied width of the test line is measured, and the adjustment of the setup is modified to minimize the width of the test line.

Abstract: A device for supplying a print bar (10) with ink has a distributor tank (16) that is connected with all print heads (12). Degassed and tempered ink is supplied to the distributor tank (16). In the distributor tank (16), a ring line (36) extends through which flows ink at the nominal temperature, and the ink (19) in the distributor tank (16) is thereby tempered. In addition to this, the distributor tank (16) has a supply line (38) via which fresh ink may be fed into the distributor tank (16). A changeover switch (42) switches between the two lines depending on the negative pressure in the distributor tank (16).

Abstract: A closed supply container that is filled with air and ink is associated with a print head in a one-to-one association. During a printing process, ink is drawn from the supply container into the print head via a connecting line, such that a negative pressure in the supply container is increased. A sensor in the supply container measures the negative pressure and transmits a measurement value to a controller that switches a valve associated with the supply container so that ink is conveyed from an ink storage container into the supply container of the measurement value falls below a predetermined first lower limit value of the pressure such that the fluid pressure in the supply container increases.

Abstract: An ink supply system for a print bar of an inkjet printing device comprises two supply lines that travel along the longitudinal axis of the print bar and direct ink with opposite flow direction. The print heads of the print bar are respectively connected to both supply lines via a connecting line in order to supply ink to said print heads. A uniform mean hydraulic pressure is produced in all print heads via the opposite flow directions in the two supply lines.

Abstract: A device for supplying a print bar (10) with ink has a distributor tank (16) that is connected with all print heads (12). Degassed and tempered ink is supplied to the distributor tank (16). In the distributor tank (16), a ring line (36) extends through which flows ink at the nominal temperature, and the ink (19) in the distributor tank (16) is thereby tempered. In addition to this, the distributor tank (16) has a supply line (38) via which fresh ink may be fed into the distributor tank (16). A changeover switch (42) switches between the two lines depending on the negative pressure in the distributor tank (16).

Abstract: In order to determine the nip between a print head and a printing substrate in an ink printing apparatus, ink droplets of a first and second size are simultaneously fired toward the printing substrate by different nozzles of a nozzle row of the print head given a predetermined feed velocity of the printing substrate, whereby print dots of a first size are generated on the printing substrate in a first two print dot row and print dots of a second size are generated on the printing substrate in a second two print dot row. The clearance of the first two print dot row from the second two print dot row is subsequently measured, and the size of the nip is determined from the measured clearance.

Abstract: A regeneration device having a planiform separating element that, to shield between the nozzle plate of a print head and a recording medium, may be moved so that the regeneration of the print head may be implemented directly above the recording medium.

Abstract: In preparation for an ejection pulse for printing a dot in a subsequent line, the actuator of a nozzle of an inkjet printer is activated in a current line with an excitation pulse via which no ink ejection is produced although an oscillation of ink in the nozzle is produced. The oscillation that is produced by the excitation pulse is thereby matched to the ejection pulse such that the ink droplets that are ejected by the ejection pulse in the subsequent line at least approximately has a defined target droplet velocity. The droplet velocity of the ejected ink droplets, and thus the droplet positioning, may thus be made uniform via the use of excitation pulses.

Abstract: A closed supply container that is filled with air and ink is associated with a print head in a one-to-one association. During a printing process, ink is drawn from the supply container into the print head via a connecting line, such that a negative pressure in the supply container is increased. A sensor in the supply container measures the negative pressure and transmits a measurement value to a controller that switches a valve associated with the supply container so that ink is conveyed from an ink storage container into the supply container of the measurement value falls below a predetermined first lower limit value of the pressure such that the fluid pressure in the supply container increases.

Abstract: A method for printing waveforms, such as overlong waveforms, can be used to enable the printing of large ink droplets. The method can include determining whether the first waveform is longer than the duration and inducing the continued activation of a nozzle arrangement with the first waveform at a second activation point in time based on the determination that the first waveform is longer than the duration. The method can include the suppression of a new activation of the nozzle arrangement to ensure the execution of the first waveform (e.g., an overlong waveform).

Abstract: A method for printing waveforms, such as overlong waveforms, can be used to enable the printing of large ink droplets. The method can include determining whether the first waveform is longer than the duration and inducing the continued activation of a nozzle arrangement with the first waveform at a second activation point in time based on the determination that the first waveform is longer than the duration. The method can include the suppression of a new activation of the nozzle arrangement to ensure the execution of the first waveform (e.g., an overlong waveform).

Abstract: Described are a system and a method to activate an actuator for a first nozzle of a plurality of nozzles of an inkjet printing system. The inkjet printer system can be configured to generate triggers with a frequency for printing of a respective line of pixels by the plurality of nozzles. The frequency of the triggers can depend on a print speed of the inkjet printing system, and the print speed can be modifiable. A time period between two successive triggers can correspond to a total duration available to the first nozzle for an ink firing for printing of a pixel of the line. An indicator for a current print speed of the inkjet printing system can be determined. Depending on the indicator for the current print speed, a waveform for activation of an actuator can be defined to produce an ink firing for printing of the pixel of the line on the recording medium by the first nozzle within the total duration available at the current print speed.