Abstract: Radiation-curable compositions of Pigment Violet 23 are described which can be used advantageously in UV inks for inkjet printing machines. Soiling containing such UV inks, especially within inkjet printing machines, can be removed particularly easily in a contactless procedure with conventional cleaners. The radiation-curable compositions described contain at least one modified Pigment Violet 23 which carries at least one polar functional group of the formula (I): —X-E?? (I) where X is a bridging group and E is a polar molecule radical.

Abstract: A method pretreats a printing material used for ink printing to influence the spreading of ink print dots on the printing material. The spreading behavior is influenced in such a way that the ink print dots spread in an anisotropic way. The anisotropic spreading advantageously allows undesired quality losses in the print that are caused by a failed ink nozzle to be reduced or avoided. The influencing of the spreading behavior may be achieved by an anisotropic application of a liquid, in particular a primer or varnish, to the printing material, or by an anisotropic embossment or print on the printing material or by an anisotropic treatment of the printing material with charged particles, in particular by a plasma or a corona, or with electromagnetic radiation, in particular laser radiation.

Abstract: A sheet-fed printing machine contains a printing unit, a drier, and a sheet handling device for transporting or guiding print sheets. The sheet handling device has an opening disposed downstream of the drier in the direction of transport. A humidification device for rehumidifying the print sheets is disposed in such a way that it rehumidifies the print sheets through the opening. The sheet handling device may contain a guide plate or several guide plates.

Abstract: Radiation-curable compositions of Pigment Violet 23 are described which can be used advantageously in UV inks for inkjet printing machines. Soiling containing such UV inks, especially within inkjet printing machines, can be removed particularly easily in a contactless procedure with conventional cleaners. The radiation-curable compositions described contain at least one modified Pigment Violet 23 which carries at least one polar functional group of the formula (I): —X-E?? (I) where X is a bridging group and E is a polar molecule radical.

Abstract: A method prints and dries a substrate where ink containing water and pigment is printed onto the substrate in an inkjet printing process. The substrate has an initial moisture content and absorbs at least water of the ink, causing the moisture content of the substrate to rise. Radiation selectively acting on the water molecules is applied in a first drying step and then radiation selectively acting on the pigment is applied in a second drying step in such a way that after completion of the two drying steps, the water of the applied ink has essentially completely evaporated and the substrate has essentially reattained its initial moisture content. In this manner optimum drying of substrates to which ink has been applied occurs.

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 sheet-fed printing machine contains a printing unit, a drier, and a sheet handling device for transporting or guiding print sheets. The sheet handling device has an opening disposed downstream of the drier in the direction of transport. A humidification device for rehumidifying the print sheets is disposed in such a way that it rehumidifies the print sheets through the opening. The sheet handling device may contain a guide plate or several guide plates.

Abstract: A method for producing a printed product includes coating a preferably paper or cardboard substrate with a precoat or supplying a substrate that has been coated with a precoat, in which the precoat contains at least one acid, applying a water-based ink to image areas on the coated substrate by using at least one ink print head, and drying the printed substrate and/or the ink, preferably using IR radiation and/or heated air. The precoat includes a photobase generator or a photobase generator is applied at least locally to non-image areas on the substrate, the substrate is irradiated at least locally in non-image areas, preferably using UV radiation, to locally generate a base, and the printed substrate is varnished with a water-based varnish.

Abstract: A method prints and dries a substrate where ink containing water and pigment is printed onto the substrate in an inkjet printing process. The substrate has an initial moisture content and absorbs at least water of the ink, causing the moisture content of the substrate to rise. Radiation selectively acting on the water molecules is applied in a first drying step and then radiation selectively acting on the pigment is applied in a second drying step in such a way that after completion of the two drying steps, the water of the applied ink has essentially completely evaporated and the substrate has essentially reattained its initial moisture content. In this manner optimum drying of substrates to which ink has been applied occurs.

Abstract: A method corrects for defective printing nozzles in an ink jet printing machine via a computer. The defective printing nozzles are compensated for after the screening process by neighboring printing nozzles applying an increased amount of ink. The method includes precalculating different compensation halftones for different area coverages by the computer, printing the compensation halftones embedded in area coverage halftone areas, evaluating the printed compensation halftones via the computer, and selecting and saving, for every area coverage level, the compensation halftone that best matches the coloration of the original halftone in the respective area coverage halftone area. A defective printing nozzle is detected during production printing by the computer. The local area coverage is determined along the detected defective printing nozzle by the computer.

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 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 digital printing machine includes a first cylinder for transporting sheets, a second cylinder for transferring the sheets directly to the first cylinder, a third cylinder for transferring the sheets directly to the second cylinder, and at least one inkjet print head directed towards the first cylinder for printing on the sheets disposed thereon. At least one first sensor measures the temperature of the first cylinder, a second sensor measures the temperature of the sheets while being transported by the second cylinder or by the third cylinder, and at least one temperature control device controls the temperature of the sheets prior to their transfer to the first cylinder. A control element adapts the temperature of the sheets to the temperature of the first cylinder. The first sensor, the second sensor and the temperature control device are connected to the control element.

Abstract: A method prints on a printing material using inks and dampening fluids. An ink printing machine uses ink print heads to apply an image to a front side of the printing material and a dampening fluid print head to apply a dampening fluid image, thus reducing or avoiding water-related cockling of the printing material. The method includes: providing the image to be printed, calculating n different color separation matrices, calculating n ink amount matrices An from the color separation matrices, and calculating a total ink amount matrix A. For every element of the total ink amount matrix: calculating a matrix B as B=G*A, with a weighting matrix G and determining the maximum of the matrix B, calculating a dampening fluid matrix C, calculating the dampening fluid image from the dampening fluid image matrix C, and printing the ink image and the dampening fluid image.

Abstract: A printed product is produced by applying at least one colored and water-containing ink to image regions on a printing material in a drop-on-demand process, applying a substantially colorless and water-containing liquid a) to non-image regions and/or b) to image regions that have little ink in a drop-on-demand process and drying the printing material. In this case, the printing material has a coating with at least one acid. After applying ink and applying the liquid, a water-containing further liquid is applied both to image regions and to non-image regions of the printing material. The first-mentioned liquid and/or the further liquid contains at least one substance for at least partly neutralizing the acid. The undesired formation of crease waves or curls and glossiness fluctuations between varnished image areas and varnished non-image areas is thus advantageously avoided.

Abstract: A method for manufacturing printed products contains the steps of applying at least one colored and water-containing ink to image regions on a printing material in a drop-on-demand process. An essentially colorless and water-containing liquid is applied a) to non-image regions and/or b) to image regions that have only little ink in the drop-on-demand process. The printing material is dried. The printing material has a coating that contains at least one acid. After the application of ink and the application of a liquid, a water-containing further liquid, for instance a varnish, is applied both to image regions and to non-image regions of the printing material, and that the liquid and/or the further liquid contains at least one substance that at least partly neutralizes the acid. The undesired formation of waves and glossiness fluctuations between varnished image regions and varnished non-image regions may thus advantageously be avoided.

Abstract: A method corrects for defective printing nozzles in an ink jet printing machine via a computer. The defective printing nozzles are compensated for after the screening process by neighboring printing nozzles applying an increased amount of ink. The method includes precalculating different compensation halftones for different area coverages by the computer, printing the compensation halftones embedded in area coverage halftone areas, evaluating the printed compensation halftones via the computer, and selecting and saving, for every area coverage level, the compensation halftone that best matches the coloration of the original halftone in the respective area coverage halftone area. A defective printing nozzle is detected during production printing by the computer. The local area coverage is determined along the detected defective printing nozzle by the computer.

Abstract: A method pretreats a printing material used for ink printing to influence the spreading of ink print dots on the printing material. The spreading behavior is influenced in such a way that the ink print dots spread in an anisotropic way. The anisotropic spreading advantageously allows undesired quality losses in the print that are caused by a failed ink nozzle to be reduced or avoided. The influencing of the spreading behavior may be achieved by an anisotropic application of a liquid, in particular a primer or varnish, to the printing material, or by an anisotropic embossment or print on the printing material or by an anisotropic treatment of the printing material with charged particles, in particular by a plasma or a corona, or with electromagnetic radiation, in particular laser radiation.

Abstract: A method prints on a printing material using inks and dampening fluids. An ink printing machine uses ink print heads to apply an image to a front side of the printing material and a dampening fluid print head to apply a dampening fluid image, thus reducing or avoiding water-related cockling of the printing material. The method includes: providing the image to be printed, calculating n different color separation matrices, calculating n ink amount matrices An from the color separation matrices, and calculating a total ink amount matrix A. For every element of the total ink amount matrix: calculating a matrix B as B=G*A, with a weighting matrix G and determining the maximum of the matrix B, calculating a dampening fluid matrix C, calculating the dampening fluid image from the dampening fluid image matrix C, and printing the ink image and the dampening fluid image.