Abstract: A device for imaging and/or varnishing the surfaces of objects or vehicles, etc. includes adapting a time lag between an application of fluid and further treatment thereof, such as drying ink or varnish, to a spreading behavior of the fluid during the application thereof. The fluid may be applied to the surface of the object in sections, firstly drying the fluid in individual sections before applying it to the next section.

Abstract: A method for reducing the effect of defective printing nozzles in a multicolor printing process on an inkjet printing machine. A computer creates a color transformation table that, for every process color of the inkjet printing machine, includes a replacement combination of the respective other process colors with a minimum color distance to the process color in question. The color transformation table is used to compensate for a defective printing nozzle. The color transformation table is created by printing and measuring a test chart with all process colors and interpolated by the computer. The color transformation table is then optimized to avoid undesired transitions between supporting points of the color transformation table and the resultant color transformation table accordingly contains process color combinations with minimum sensitivity to defective printing nozzles and the optimized table is used to carry out the multicolor printing operation on the inkjet printing machine.

Abstract: A belt conveyor for printing sheets includes an outer belt on which the printing sheets rest during transport. The belt conveyor also includes an inner belt. A chain is disposed between the inner belt and the outer belt. The inner belt drives the chain and the chain drives the outer belt.

Abstract: A device for adjusting print heads, in particular inkjet print heads of an inkjet printing machine, on a print bar includes motors disposed in a row and supported for joint movement. Every motor carries a motor gearwheel and every motor gearwheel is successively engageable with at least two respective adjustment gearwheels.

Abstract: A method for alternately operating an inkjet printing machine applying a plurality of inks to a printing material in accordance with a print image, includes conveying the printing material at a conveying speed. A switch is made between the following two modes, a 1st mode of printing an n-color first print job at a first conveying speed and at a print resolution using n inks, i.e. using black ink and n?1 different chromatic inks; and a 2nd mode of printing a reduced-color second print job at a second conveying speed greater than the first conveying speed and at the same print resolution using the n inks. The printing speed and thus the number of prints produced per unit of time in a machine can therefore advantageously be increased.

Abstract: A printing machine for printing on a web includes a first roller and a second roller between which the web forms a loop. A trough for pneumatically guiding the loop equidistantly to the major part of the length of curvature of the trough is provided between the first roller and the second roller.

Abstract: A method for compensating for defective printing nozzles in an inkjet printing machine by way of a computer. Defective printing nozzles are compensated for by an increased ink drop volume of neighboring printing nozzles and the real positions of the print dots of all printing nozzles are determined and, to compensate for a printing nozzle failure, the required ink drop volumes of the respective neighboring printing nozzles are calculated for every printing nozzle as a function of the real positions of the print dots of the respective neighboring printing nozzles. In addition to increased ink drop volumes of the respective neighboring printing nozzles, reduced ink drop volumes are calculated for the respective next but one printing nozzles and all ink drop volumes are calculated based on the print dots of the respective printing nozzles.

Abstract: A method for inkjet printing machine color control includes color transformation of print data from first color space to process color space in a first stage using a computer transforming print data from the first to an intermediate color space while keeping special colors, and a second stage transforming corrected print data including special colors from intermediate to process color space. The computer uses print data corrected after the first stage as second stage starting values. Print data transformed into the process color space are printed. First color space corresponds to CMYK, flexographic printing or RGB color space with special colors, intermediate color space corresponds to CMYK color space with special colors, process color space corresponds to CMYK color space with additional process colors. The computer corrects CMY, not K print data or special not transformed colors, when correcting print data in the intermediate color space after the first stage.

Abstract: A printing device includes an ink jet print head having individually controllable nozzles for jetting ink drops. An ink line connected to a chamber has a feed and/or return line for the print head. The print head, ink line and chamber move jointly relative to printing material. The ink line is part of a circulation ink supply system for the print head. A mass element associated with the chamber has a position and/or shape relative to the chamber changing as a function of the joint movement so that the chamber volume is a function of the position and/or shape of the mass element to compensate for pressure fluctuations and/or movements of the ink and avoid problems in the ink supply system for a print head in industrial, high-performance ink jet printing and in cooperation with circulation ink supply systems conveying large volumes of ink.

Abstract: A print bar for inkjet printing includes a crossbar carrier, a row of head mounts carried by the crossbar carrier, and print heads held by the head mounts. Every head mount has lateral guide profiles for linearly guiding the head mounts. The guide profiles of respective adjacent or neighboring head mounts engage in one another.

Abstract: A method detects defective printing nozzles in an inkjet printing machine having a computer. The method includes printing a multi-row nozzle test chart for detection purposes, the test chart contains a number of horizontal rows of equidistant vertical lines printed periodically and disposed underneath one another. Wherein in every row of the nozzle test chart periodically only those respective printing nozzles of the print head contribute to the first element of the nozzle test chart that correspond to the specified number of the horizontal rows. An area coverage element geometrically associated with the nozzle test chart is printed. Both elements are recorded by an image sensor and both elements are evaluated by the computer. Defective printing nozzles are identified by evaluating the recorded nozzle test chart by the computer. Defects are allocated in the area coverage element to the printing nozzles in the nozzle test chart by the computer.

Abstract: A mounting device for a print head and a printing system allows print heads to be easily changed and easily and reliably adjusted. The mounting device includes a rigid mount and a frame for receiving a print head. The frame is releasably fixed to the rigid mount and includes an adjustment device for adjusting the print head relative to the rigid mount. The adjustment device of the frame includes two solid body joints and two actuators for adjusting the print head in two degrees of freedom, namely in a sliding movement along the rigid mount and a rotary movement about the vertical axis.

Abstract: A method for detecting and compensating for defective print heads in an inkjet printing machine uses a computer to analyze printing nozzle test charts and/or area coverage elements to obtain characteristic values of individual printing nozzles in a print head, to calculate the failure probabilities of these printing nozzles on the basis of thresholds, and to compensate for a printing nozzle that exceeds a specified failure probability. The computer uses the individual failure probabilities of the individual printing nozzles in a print head to calculate the failure probability of the print head and initiates compensation measures as a function of the calculation. The thresholds correspond to a multi-dimensional characteristic value threshold based on which the computer calculates the failure probability of a printing nozzle by using an algorithm including kernel density estimation through a multidimensional distribution function.

Abstract: A method for image inspection of printed products in a printing material processing machine includes using an image sensor to capture and digitize printed products during image inspection by an image capture system, using a computer to carry out a comparison of captured digital printed images with a digital reference image, examining a result of the comparison for image regions with blurry regions in the captured digital printed image, calculating suitable smoothing factors for the blurry image regions, and then carry out smoothing of the digital reference image with the calculated, suitable smoothing factors for the blurry image regions, causing the digital reference image to have a blurriness comparable to the captured digital printed image in the image regions. Printed products detected as faulty are removed upon an occurrence of deviations of the captured digital printed image from the digital reference image.

Abstract: A method for printing tracks on bodies by using inkjet printing provides printed images with a homogeneous appearance on the bodies, in particular when printing large single-color areas. The homogeneous appearance is obtained by reducing the intensity of the UV radiation from at least one inkjet print head when pinning in track connection regions.

Abstract: A method for detecting defective printing nozzles in an inkjet printing machine includes printing a multi-row printing nozzle test chart formed of horizontal rows of equidistant vertical lines periodically underneath one another, with only printing nozzles in a print head contributing to every row of the test chart corresponding to the horizontal rows. An area coverage element geometrically associated with the test chart is printed, both elements are recorded by an image sensor and analyzed by the computer. The computer analyzes the recorded area coverage element to detect print defects and allocates defects to a region of geometrically close printing nozzles. An analysis of the test chart in the region identifies nozzles causing the defect. Defective printing nozzles are detected based on thresholds, the detected printing nozzles are then compensated, and in the analysis of the recorded area coverage element, influences of the sensor are eliminated by shading correction.

Abstract: A method detects defective print nozzles in an inkjet printing machine by a computer. In a first phase within the context of a print job, print nozzle test patterns are printed beside a subject on a printing substrate. These print nozzle test patterns are then digitized by an image sensor and sent to the computer, where they are analyzed by the computer to determine the current state of the print nozzles, including defective print nozzles. After the first phase, the print nozzle test patterns are modified by the computer on the basis of the current state of the print nozzles and, in a second phase, the modified print nozzle test patterns are printed, digitized and evaluated by the computer with regard to the determination of the current state of the print nozzles and defective print nozzles.

Abstract: A method for modifying color density values in a dot-based printing system uses a control unit. The control unit implements the modification of the color density values after a raster image has been created and modifies the number and/or size of print dots to be applied to a printing substrate in order to attain pre-defined color density target values.

Abstract: A method for detecting and compensating for defective printing nozzles in an ink jet printing machine by using a computer includes printing printing nozzle test charts next to an actual print in a production run, subsequently recording and digitizing the printed printing nozzle test charts by using at least one image sensor, evaluating recorded test charts and, based thereon, defining characteristic values for all printing nozzles contributing to the printed printing nozzle test charts by using the computer, calculating a failure probability for every contributing printing nozzle based on the determined characteristic values by applying a statistical prediction model using the computer, and switching off and compensating for all printing nozzles exceeding a first defined threshold for the calculated failure probability. A printing operation is then carried out on the ink jet printing machine with printing nozzle compensation.

Abstract: A method for detecting printing nozzle errors in an inkjet printing machine provides a high degree of robustness in the detection of errors by printing a nozzle test pattern in the inkjet printing machine. The test pattern is then digitalized by using a camera and transmitted to a computer for evaluation. There, the recorded test pattern is investigated by using methods of digital image processing, such as a Fourier analysis, and evaluated in the frequency range with regard to specific anticipated printing nozzle errors. Specific printing nozzle errors can be detected especially on the basis of amplitude, phase and variance errors in the signal in the frequency range. Moreover, by using the phase error, it is possible to evaluate whether the two print heads are disposed in an incorrect adjustment position relative to one another by calculating displacements of the phase error in transition regions of two print heads.