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 droplet velocities of the nozzles of different groups of nozzles of a print head of an inkjet printing device are determined for different line clock rates. An optimized operating line clock rate is then determined for the operation of the printing device, where the deviation between the droplet velocities of the nozzles of the different groups is reduced (e.g. minimized). The droplet positioning along the transport direction of a recording medium may be advantageously homogenized via the convergence of the droplet velocities.

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 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: 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 inkjet printer having at least one print head in which at least one edge region nozzle at the edge of the print head is not activated for the printing of a print image, but nevertheless is activated at least temporarily with non-ejection pulses without ink ejection. Intensity fluctuations of the dots of a print image that are printed by the remaining nozzles of the print head may be reduced via the activation of an edge region nozzle with non-ejection pulses.

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: 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: 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 degassing device can include one or more passive components, such as a gas-permeable membrane. The passive components may not directly be monitored. The state (e.g. the permeability) of the passive components may be reliably determined via evaluation of pressure information with regard to the pressure (e.g. negative pressure) in the degassing device.

Abstract: The droplet velocities of the nozzles of different groups of nozzles of a print head of an inkjet printing device are determined for different line clock rates. An optimized operating line clock rate is then determined for the operation of the printing device, where the deviation between the droplet velocities of the nozzles of the different groups is reduced (e.g. minimized). The droplet positioning along the transport direction of a recording medium may be advantageously homogenized via the convergence of the droplet velocities.

Abstract: A method to increase the print quality of a printer can include determining sensor data corresponding to a print image printed by a print head of the at least one print head of the printer onto the recording medium; determining, based on the sensor data, undulation information corresponding to unevenness of the recording medium, a distance between the one or more nozzles of the print head of the printer and the recording medium varying due to the unevenness; and printing, based on the undulation information, a subsequent print image with the print head of the printer. The printer can include at least one print head including one or more nozzles that are configured to fire ink droplets onto a recording medium to generate a print image on the recording medium.

Abstract: In a method to active print nozzles of an inkjet printer including a print head having print nozzles and respective actuators associated with each of the print nozzles, one or more conveying pulses are generated to eject respective droplets of ink from the respective print nozzle; and the actuator is activated with one or more intermediate pulses having an amplitude and/or a duration that is less than an amplitude and/or a duration of the one or more conveying pulses. The one or more intermediate pulses can be configured such that no ink is ejected from the respective print nozzle with the one or more intermediate pulses.

Abstract: A degassing device can include one or more passive components, such as a gas-permeable membrane. The passive components may not directly be monitored. The state (e.g. the permeability) of the passive components may be reliably determined via evaluation of pressure information with regard to the pressure (e.g. negative pressure) in the degassing device.

Abstract: An inkjet printer having at least one print head in which at least one edge region nozzle at the edge of the print head is not activated for the printing of a print image, but nevertheless is activated at least temporarily with non-ejection pulses without ink ejection. Intensity fluctuations of the dots of a print image that are printed by the remaining nozzles of the print head may be reduced via the activation of an edge region nozzle with non-ejection pulses.

Abstract: In a method to check a fixative print head for nozzle failures, a reference mark is printed by the nozzles of a colored ink print head and a test mark is printed via overprinting of the colored ink by the nozzles of the colored ink print head and of a fixative by the nozzles of the fixative print head onto a printing substrate web. The test mark and the reference mark are compared with one another. If the reference mark and the test mark correspond to one another (e.g., at least in part), this indicates that nozzles of the fixative print head are operating incorrectly. If operating incorrectly, the nozzles have, for example, failed entirely or eject the fixative at too great an angular deviation.

Abstract: A method for reducing a locally increased viscosity of ink in an ink print head of an ink printer during printing operation includes: a determination of a printing pause with the aid of a pixel preview; an application of a first sequence of pulses for measurement of the activation current of a piezoelement of the ink print head; and an application of a second sequence of pulses for vibration of the ink meniscus at the exit of a nozzle if the ink print head to intermix the ink having locally increased viscosity with ink having the initial viscosity given a threatened failure of the nozzle.

Abstract: In a method to active print nozzles of an inkjet printer including a print head having print nozzles and respective actuators associated with each of the print nozzles, one or more conveying pulses are generated to eject respective droplets of ink from the respective print nozzle; and the actuator is activated with one or more intermediate pulses having an amplitude and/or a duration that is less than an amplitude and/or a duration of the one or more conveying pulses. The one or more intermediate pulses can be configured such that no ink is ejected from the respective print nozzle with the one or more intermediate pulses.

Abstract: A method to increase the print quality of a printer can include determining sensor data corresponding to a print image printed by a print head of the at least one print head of the printer onto the recording medium; determining, based on the sensor data, undulation information corresponding to unevenness of the recording medium, a distance between the one or more nozzles of the print head of the printer and the recording medium varying due to the unevenness; and printing, based on the undulation information, a subsequent print image with the print head of the printer. The printer can include at least one print head including one or more nozzles that are configured to fire ink droplets onto a recording medium to generate a print image on the recording medium.

Abstract: In a method for an inkjet printing system, substantially parallel lines are printed in the transport direction with nozzles at different longitudinal positions along the transport direction of the recording medium. Based on the variations of the transversal distance of corresponding image points of the substantially parallel lines, the transversal movement of the recording medium may be detected and a dimension of the transversal movement may be determined.