Abstract: In a method to clean nozzles and ink channels of at least one ink print head with a flushing medium in an ink printing apparatus, a necessary flushing quantity of the flushing medium that is to be provided and which is necessary for flushing of the ink print head in a flushing process is determined from either a predetermined flushing quantity predetermined depending on a print duration of the ink printing apparatus or from a drive flushing quantity derived from a flushing quantity curve that indicates a dependency of the flushing quantity on an elapsed time for an ink used in printing, the necessary flushing quantity being either said predetermined flushing quantity or the derived flushing quantity, whichever is greater. The determined necessary flushing quantity is used to flush the ink print head.

Abstract: In a method to determine particle mass concentration in a dispersion having particles and fluid, the dispersion in a measurement cell is exposed to an alternating field of variable frequency to set the particles into oscillation to generate sound pressure waves. Amplitudes of the sound pressure waves are measured depending on the frequency so that a maximum amplitude of the sound pressure waves is established and a frequency associated with the amplitude is determined as a resonance frequency of the sound pressure wave. The mass concentration of the particles in the dispersion is established from the resonance frequency.

Abstract: In an arrangement to supply ink to a print head unit having a print head, an input, and an output, a back-pressure tank having ink is provided and connected with the input of the print head unit. A degassing unit for ink and having an input and an output is also provided. A first selector valve is connected to the degassing unit input, the first selector valve in a first position establishing a connection of the degassing unit with the output of the print head unit. A second selector valve is connected to the degassing unit output, the second selector valve in a first position establishing a connection of the degassing unit with the back-pressure tank.

Abstract: In a method to output document data divided into pages at an output printing apparatus, a print file encoded in a page description language is provided with per-page variable document data and bin command data, the bin command data referring to at least one page input tray of a reference printing apparatus for page-shaped recording material. The page input tray is provided to accept form pages with at least one pre-print image. At least one macro data set is created that contains a group of commands of the page description language and pre-print image data with which the pre-print image can be reproduced as a rastered image. Association data are generated for an association between the bin command data and the macro data set. The print file is sent as a data stream from a document data computer to a controller. In the controller the variable document data are merged and rastered with the pre-print image data using the bin command data and the association data.

Abstract: In a method to adjust hue of a print images by toner layer thickness a photoconductor element is charged to a charge potential. A potential image of the print image made up of image points is generated via exposure and discharge of the photoconductor element. The potential image is inked by charged toner via a developer element at a BIAS potential. With a character generator, generating a potential of an individual image point of the print image via local discharge of the photoconductor element, the potential of the image point lying between the BIAS potential and a potential established by a maximum achievable discharge depth of the photoconductor element, and so that the individual image points have same or different potentials, depending on the exposure, so that the exposed area overall has a resulting potential, and a depositing of toner on this area and therefore the toner layer thickness on this area is proportional to the resulting potential.

Abstract: In a method or system to operate a digital printer for double-side printing to a recording medium with toner particles applied with a liquid developer, the digital printer prints first and second sides of the recording medium in succession. Electrophoretic mobility of toner particles of a first toner image on the first side is reduced after application of said first toner image and before application of the second toner image on the second side of the recording medium. The electrophoretic mobility is reduced by drying the first toner image along a drying route in an airflow generated by a blower such that carrier fluid is thus removed from the first toner image. After the application of the second toner image on the second side of the recording medium, both the first and second toner images are simultaneously fixed.

Abstract: In a method to execute a printing interruption in a printing operation of an ink printing system in which a printing substrate is printed with at least one print head during the printing interruption in which a feed speed of the printing substrate web comes to a standstill, at least one vibration pulse is sent to the at least one print head to trigger vibration oscillations before a print controller loads print data into the at least one print head. Thereafter a print-start signal is sent to the at least one print head.

Abstract: In a digital printer comprising a developer station using liquid developer, the developer station has an application unit via which liquid developer is transported to a charge image carrier. The supply system adjacent and lateral to the application unit supplies liquid developer to the application unit. A pre-chamber and an electrode segment are provided, the pre-chamber being filled with liquid developer and open towards the application unit. The pre-chamber is open at a top such that a compensation volume of liquid developer with an open surface is created past which the application unit passes. The electrode segment is arranged adjacent to the pre-chamber and to a side of the application unit such that it forms a gap with the application unit through which the liquid developer is directed, the electrode segment being at an electrical potential such that toner of the liquid developer transfers to the application unit in the gap.

Abstract: In a method or digital printer to print a recording material with toner particles applied with a liquid developer, toner concentration of the liquid developer is determined via measurement with aid of ultrasonic pulses. At least one ultrasonic pulse is generated by discharging an ultrasound emitter charged with a charge voltage. The ultrasonic pulse permeates the liquid developer and is received by an ultrasound receiver which generates a reception signal corresponding to the received ultrasonic pulse. With a control device, the charge voltage is regulated to a value such that a representative value of the reception signal corresponds to a predetermined desired value. The toner concentration is determined from the regulated charge voltage.

Abstract: When cleaning inkjet print heads, a first cleaning fluid is provided which includes at least one cellulase or a catalytically active derivative thereof. A contaminated and/or blocked inkjet print head (12) is cleaned using this first cleaning fluid.

Abstract: In a method to execute a pause function in an inkjet printing system with at least one printing apparatus, the pause function is triggered to reduce a feed speed of the printing substrate web from a speed during printing operation to a predetermined speed for a predetermined duration. The duration is selected so that the printing substrate has suitable properties with regard to at least one of the elements selected from the group consisting of moisture and temperature under the printing unit of the printing apparatus at an end of the pause function. After ending the pause function, the printing substrate web is accelerated again to the speed during the printing operation.

Abstract: In a method or system for printing of a recording medium, potential images of images to be printed are generated on a potential image carrier. The potential images are developed into an image film comprising image regions and non-image regions on the potential image carrier via application of a liquid developer comprising a polymerizable carrier fluid with dye particles suspended therein. The image film is transferred onto the recording medium. The image film is fixed on the recording medium via a cross-linking reaction of the carrier fluid such that the dye particles of the image regions are embedded in a fixed polymer matrix and the carrier fluid hardens into a transparent film that permanently bonds with the recording medium. The cross-linking reaction of the carrier fluid is started, accelerated, or extended by at least one component.

Abstract: In a method to execute a pause in an ink printing system printing operation in which a printing substrate web is printed with print bars having print heads, with aid of a take-up roller moving the printing substrate web at printing speed past the print bars in a transfer printing zone in order to generate print images. Upon triggering the pause, a strain state of the printing substrate web is measured at a beginning of the pause and stored as a desired strain state. During the pause, the strain state of the printing substrate web is measured as a real strain state at selectable points in time, and the real strain state is compared with desired strain state. Given a deviation of the real strain state from the desired strain state, at the selectable points in time the take-up roller is controlled so that the strain state of the printing substrate web assumes the desired strain state at the beginning of the pause.

Abstract: To activate a processing device which processes a surface of a moving work piece at regular intervals, wherein a predetermined time duration passes between an activation signal of the processing device and the processing on the surface, the movement of the work piece is sensed with a sensor that generates work pulses. A respective control pulse is generated if a predetermined number of work pulses has been generated. A number of the work pulses is repeatedly detected in a respective time interval that corresponds to the predetermined time duration. The activation signals are each generated at each control pulse of a series, and the activation signals are offset forward in time relative to the respective control pulse corresponding to the number of work pulses that have been detected in the respective time interval. The activation signals are output to the processing device.

Abstract: In a system or method for supplying print bars with a plurality of print heads with ink in an inkjet printer, a pressure source is activated in a flushing procedure in order to exert an excess pressure to the ink in intermediate tanks supplying ink to the print bars such that the ink is flushed through jets of a print head to be flushed in the respective print bar. The pressure source is shut off when printing. The ink in the intermediate tanks is transported to the print heads by means by hydrostatic pressure. In the event of an overflow of the intermediate tanks, overflowing ink is transported into an overflow container via a respective pressure line connecting the overflow container to the respective intermediate container.

Abstract: In a method or device to control at least one property of a print image printed on a substrate, a first evaluation period is defined. A measurement value is determined with aid of an optical sensor which measures at least one determination point on the substrate within the first evaluation period, and also determining a position of the determination point within the first evaluation period. The determined measurement value is compared with a preset reference value. Depending on a result of the comparison, an inking of the substrate is controlled for the print image in at least one subsequent second evaluation period at a point within the second evaluation period which has a position within the second evaluation period that corresponds to said position of the determination point in said first evaluation period.

Abstract: In a method for printing recording media successively supplied to a printing unit, and wherein a sheet gap is provided from a preceding recording medium, document print data are subjected to a rastering process. A predetermined nominal number of lines is respectively provided for the document print data of a page. The raster print data are successively stored line by line in a print data memory region of an electronic memory. A blank line memory region for a blank line that is not to be filled with print data is provided in the memory. The raster print data are successively read out per line from the print data memory region of the memory and are supplied to the printing unit. After the read out of the nominal number of lines from the print data memory region, the blank line memory region is then read out a number of times, said number of times being a whole number greater than or equal to zero and being dependent on the sheet gap.

Abstract: In a method to operate a digital printer having multiple developer stations operated with liquid developer, and wherein a number of the developer stations participating in printing is dependent on a respective print operating mode, liquid developer is supplied from a mixing container to at least one of the developer stations. With a regulatory device a fill level of liquid developer in the mixing container is kept substantially constant depending on the print operating mode. A desired different operating value is provided for the fill level for the regulatory device depending on the operating mode.

Abstract: In a method to execute a print interruption, a printing substrate is printed to with a printing unit with at least one print head. With aid of a sensor, print clock pulses are generated that are supplied to a print controller depending on a feed of the printing substrate. With triggering of the print interruption, a feed speed of the printing substrate is reduced from a print speed in the printing operation to a predetermined speed according to a deceleration ramp. After the print interruption the printing substrate is accelerated again to the print speed according to an acceleration ramp. Given occurrence of a print clock pulse during at least one of the ramps, the print controller sends at least one vibration pulse to the at least one print head so that at least one cycle of vibration oscillations is implemented at the print head. The at least one vibration pulse is generated if a time interval of the print clock pulses relative to one another reaches a predetermined value.

Abstract: In a method to execute a pause function of an ink printing system wherein a printing substrate web is printed with a printing unit with print bars having print heads, a real value of a web tension of the printing substrate web is measured with a web tension sensor. In a printing operation the real value of the web tension is regulated to a predetermined desired operating value of the web tension. With triggering of the pause function, the web tension is further regulated by modifying the desired value of the web tension so that the printing substrate web assumes a position at the print heads after an end of the pause function that it had before a beginning of the pause function. After the end of the pause function, the real value of the web tension is regulated again to the desired operating value of the web tension.