Method for printing a decoration onto a carrier material

Abstract

The invention relates to a method for digitally printing a decoration onto a carrier material using at least one set of defined printing parameters. The method comprises the steps of i. providing an analogue decoration; ii. creating and saving at least one digital image of the analogue decoration in the form of digital decoration raw data in the RGB colour space; iii. digitally processing at least a part of the digital decoration raw data in the RGB colour space and creating processed digital decoration raw data; iv. providing at least one set of printing parameters; v. transferring the processed digital decoration raw data and the at least one set of printing parameters to colour management or RIP software and calculating colour-space-profiled production data for the at least one set of printing parameters from the processed digital decoration raw data; vi. calculating separation data from the colour-space-profiled production data calculated for the at least one set of printing parameters; vii. outputting a digital image of the analogue decoration with the calculated separation data onto a carrier material using a digital printer, wherein the digital printer is comprised by the at least one set of printing parameters for which the colour-space-profiled production data have been calculated.

Description

[0001] Method for printing a decoration on a carrier material

[0002] The invention relates to a method for digitally printing a decoration onto a carrier material using at least one set of defined printing parameters. The method comprises the steps of: i. providing an analog decoration; ii. generating and storing at least one digital image of the analog decoration in the form of digital decoration raw data in the RGB color space; iii. digitally processing at least part of the digital decoration raw data in the RGB color space and generating processed digital decoration raw data; iv. providing at least one set of printing parameters; v. transferring the processed digital decoration raw data and the at least one set of printing parameters to color management or RIP software and calculating color space-profiled production data for the at least one set of printing parameters from the processed digital decoration raw data; vi.Calculation of separation data from the color space profiled production data calculated for the at least one set of printing parameters; vii. Output of a digital image of the analogue decor with the calculated separation data by a digital printer onto a carrier material, wherein the digital printer is included in the at least one set of printing parameters for which the color space profiled production data was calculated. For the production of decors, in particular for floor panels, furniture components or worktops, printing cylinders are usually used in the gravure printing process. A printed decor is usually created from a digitized analogue decor which is available as a real material such as wood. The digital data of the analogue decor, i.e. its digital images, are usually created by scanning or digital photography. These images are recorded on a digital monitor thanks to the red / green / blue sensors in digital cameras orScanners capture and save the data in the RGB color space. The RGB color space is an additive color space that simulates color perception through the additive mixing of the primary colors red, green, and blue. To transfer this digital RGB decorative data set to a printing cylinder set with several individual colors, the data for the individual colors to be printed must be separated.

[0003] In addition to the historically developed gravure printing process, digital printing is now increasingly being used in decorative printing. With digital printing, the print pattern is transferred directly from a computer to a digital printer, such as a laser or inkjet printer. Therefore, static printing forms are not required in digital printing, eliminating limitations on the length and width of the print data. Digital printing thus offers a high degree of flexibility and variability in terms of print motifs and imposes no restrictions on the pattern repeat. In printing, pattern repeat refers to a constantly recurring, identical print pattern.

[0004] One of the most well-known color models is the CMYK color model, which uses the primary colors cyan, magenta, yellow, and black for printing. The CMYK color model is a subtractive color model, where the abbreviation CMYK stands for the three color components cyan, magenta, yellow, and the black component, the key, as the color depth. This color system can be used to represent a color space (gamut) that meets many requirements from a wide variety of areas. If a digital printer uses the CMYK color model, the digital printer has four color channels: one for cyan, one for magenta, one for yellow, and one for key.

[0005] According to the state of the art, the digital data is color space profiled. This involves determining the printing parameters relevant for printing, such as

[0006] • Type of printing system (including printing speed,

[0007] printhead properties, etc.);

[0008] • Color model to be used for printing (e.g. 4-color channel printing system, 5-color channel printing system, use of special colors, etc.);

[0009] • Temperature; • Humidity;

[0010] • Type / batch of printing ink;

[0011] • Type / batch of the carrier material being printed;

[0012] • Pretreatment of the substrate material (e.g. by priming) is taken into account.

[0013] The printing parameters determine the color space that can be displayed in print. The color space describes the totality of colors that can be displayed with the given printer parameters. The color space of the color-space-profiled production data, i.e., the digital data after color space profiling, is generally smaller than the RGB color space in which the digital data of the analog decor is available, because the color space is limited by the printing parameters.

[0014] The type of printing ink changes the appearance of the printed colors, for example due to the pigments it contains. In addition, different batches of the same printing ink can show differences in their printed appearance. The same applies to the substrate onto which the print is made. Under otherwise identical printing parameters, a print on a wood-based panel will have a different appearance than a print on glossy paper. Even when printing on paper, the appearance of the printed colors depends on the paper used, for example whether a white or yellow / brownish paper is used. Furthermore, papers from different manufacturers differ in terms of their base color. The substrate can also be pre-treated in a variety of ways, e.g. by priming.Priming changes the background during printing and thus the color effect of the print.

[0015] The choice of printing system already influences the color space in which printing can be done, as different printing systems have different printing speeds and / or printhead settings, among other things, which in turn influence the color space. Furthermore, different printers use different color models for printing.

[0016] Climatic conditions during printing also influence the color space; for example, the ink dries at different speeds during printing depending on temperature and humidity. The color space-profiled production data for different printing parameters therefore differ from one another and can represent color spaces of varying sizes depending on the printing parameters.

[0017] Separation data is calculated from the color space profiled production data for the digital printer used for printing. In print shops, the separated print data is usually also used for digital printing, similar to that used for gravure printing. For use in digital printing, the data of a digital image is converted using RIP (raster imaging process, RIP) software into a format that can be processed by a digital printer. The RIP software separates the color information contained in the digital image, among other things, into the color channels that are part of the color model of the digital printer to be used for printing. The digital print is then output via the digital printer using the corresponding color model. Separation data can be calculated, for example, using RIP software, color management software, or printer-internal software.

[0018] The separation data, like the profiled production data, therefore depend on the printing parameters. In particular, the separation data for printing a design will vary on different printing systems. Printing systems in this context include digital printers, either alone or in a system with additional devices, such as devices for priming and / or transporting substrates.

[0019] Traditionally, the separation data is calculated from the color-space-profiled production data for a print under defined printing parameters. This separation data is then digitally processed, for example, to make color adjustments to the decor or for retouching. In this process, the color information present in the color channels is processed and modified.

[0020] However, for the reasons already described, the separation data available for one set of printing parameters cannot simply be applied to other printing parameters. This means, in particular, that the separation data cannot simply be used for a different printing system. For each change in printing parameters, new color-space-profiled production data, and thus new separation data, must be calculated. This separation data must then be digitally processed to implement desired retouching, such as color adjustments to the decor.

[0021] EP 3 470 972 A1 relates to a method for the multiple use of digital print data to create optically and / or haptically high-quality print decorations on a substrate. In the method, separation data of a digital print motif is created, whereby the data of the individual color channels can subsequently be processed individually to retouch the digital print motif.

[0022] However, the current state of the art has numerous disadvantages. The manual separation of individual colors prior to printing using a defined set of printing parameters is time-consuming in the production process and thus increases production costs. While the digital data of the analog decoration is available in the extensive RGB color space after it has been created, the color space of the decoration after the calculation of the color-space-profiled production data and its separation is limited to colors and / or spot colors of the color model used in printing. The color-space-profiled production data and the separation data generated by the separation cover a significantly smaller color space than the original digital data of the analog decoration in the RGB color space. In particular, separation data for a second printing system cannot be obtained based on existing separation data for a first printing system.In this case, there would generally be a loss in the quality of the print image.

[0023] For example, if separation data is available for printing with a 4-color system, it cannot be used to calculate separation data for printing on a printing system with a 5-color system. In this case, data with a lower information content (for 4 color channels) would have to be used to generate data with a higher information content (for 5 color channels). This means that a consistently high quality standard in printing cannot be guaranteed.

[0024] The invention is therefore based on the object of providing a method for digitally printing decorations which can be carried out as flexibly as possible with different printing parameters, in particular different printing systems, and which eliminates the disadvantages of the methods known from the prior art.

[0025] For this purpose, the invention provides a method according to claim 1. Detailed description

[0026] According to the method according to the invention, an analogue decor is provided. Analogue decors can essentially be any material that exists in reality and whose appearance is suitable for decorating. In particular, wood, tile, and stone surfaces can serve as analogue decors. Analogue decors within the meaning of the present invention can also be templates produced using other printing techniques such as gravure printing, screen printing, or even manual techniques. These decors are particularly popular in the design of laminates used for floor, wall, and / or ceiling coverings.

[0027] In a preferred embodiment, the method according to the invention is preferably used for printing carrier materials for the production of floor laminates or wall and ceiling cladding elements.

[0028] Subsequently, at least one digital image in the form of digital raw decor data in the RGB color space is generated from the analog decor and stored. In one embodiment of the invention, the at least one digital image and thus the digital raw decor data of the analog decor are generated by photographing the analog decor with a digital camera or by scanning the analog decor with a scanner.

[0029] The RGB color space is the largest color space in which digital images can be processed and includes all color spaces in which digital printing can be used.

[0030] In one embodiment, multiple digital images of the analogue decor can be generated. For example, the analogue decor can be photographed or scanned from different angles, using different camera or scanner settings. A composite image can then be calculated from the different digital images. Software for scanners is also known from the prior art, in which an analogue decor is scanned in three different modes, i.e., under three different conditions (scanner settings, exposure, etc.), and a composite image is subsequently generated. In the method according to the invention, the digital composite image can then be further processed digitally. The digital composite image then represents the digital raw decor data within the meaning of the invention.

[0031] During photography or scanning, in one embodiment, special effects such as shading can be created by using special lighting techniques and varying the position of the camera or scanner over the analogue decor.

[0032] According to the method, at least a portion of the digital decor raw data is digitally processed in the RGB color space. During the digital processing of at least a portion of the digital decor raw data, at least a portion of the decor raw data can be retouched. According to the invention, this generates processed digital decor raw data. According to the invention, the processed digital decor raw data is still available in the RGB color space.

[0033] In one embodiment of the present invention, at least a portion of the digital decorative raw data is processed using Adobe Photoshop. In principle, however, any image editing or graphics editing program that allows for editing, particularly retouching, digital image data in the RGB color space is suitable. The editing of the digital decorative raw data can, for example, be performed by a user on a PC using suitable software, such as Adobe Photoshop.

[0034] Retouching is the subsequent image processing of the digital decorative raw data of a photographed or scanned analogue decoration.

[0035] • one or more color tones are changed; and / or

[0036] • the brightness is changed; and / or

[0037] • the saturation is changed; and / or

[0038] • the contrast can be changed; and / or

[0039] • the sharpness can be changed.

[0040] During retouching, the appearance of the digital image, which is described by the digital decoration raw data, can be altered as desired. The processing steps described below always refer to changing the appearance of the digital image, which is described by the digital decoration raw data. For this purpose, the digital decoration raw data is edited.

[0041] This way, for example, errors in the digital image can be corrected. Furthermore, dust that was present on the analogue decor during digitization can be removed as a visual appearance from the digital image and thus from the digital decor raw data. In the case of wood decors, for example, knots can be removed, added and / or changed, e.g. their size. Furthermore, repeat patterns can be created. In one embodiment, decors intended for floorboards are processed in such a way that the plank divisions are no longer visible in the digital image. This has the advantage that after digital printing in the repeat, planks of any width can be cut from the printed carrier material.

[0042] The sharpness of the digital image, or of specific areas of it, can be adjusted. Areas can be made sharper or blurrier. Furthermore, the color and saturation of highlights and midtones can be adjusted separately.

[0043] Retouching makes it possible to emphasize structures in the digital image of the analogue decor or to make them less prominent, for example by changing the color scheme in those areas. This allows, for example, pores in wood structures, knots, or similar patterns in decors to be emphasized or not emphasized. Adobe Photoshop, in particular, offers the option of working with multiply layers. Using this function, a decor layer can be copied in the software and placed on top of another decor layer. The upper decor layer can be displayed transparently, which advantageously makes the underlying decor layer appear visually more pronounced.

[0044] Retouching can also alter the color scheme. For example, different color ranges can be created in a monochromatic decor, giving the overall digital image of the analog decor more dynamism. Conversely, colors can be reduced or adjusted in particularly dynamic digital images of an analog decor, thus giving the digital image of the analog decor a more tranquil appearance.

[0045] Furthermore, it is possible to perform geometric operations such as rotations, reflections or even regrouping certain parts of the digital image.

[0046] The raw digital decor data can thus be optimally adapted to customer requirements. This processing is advantageously carried out in the largest possible color space available, namely the RGB color space. This ensures the maximum amount of data is available for processing.

[0047] In one embodiment of the method according to the invention, not just a portion of the raw decorative data is processed, but the entire raw decorative data. This makes it possible to perform retouching across the entire digital image or only for selected sub-areas of the digital image.

[0048] By processing the raw decor data, a processed digital image of the analogue decor is created, the appearance (optical impression) of which is different from the unprocessed digital image of the analogue decor, as created in process step ii.

[0049] According to the invention, at least one set of printing parameters is provided. According to the invention, printing parameters are selected from the group comprising:

[0050] • Type of printing system (including print speed, print head characteristics, etc.);

[0051] • Color model to be used for printing (e.g. 4-color channel printing system, 5-color channel printing system, use of special colors, etc.)

[0052] • Temperature;

[0053] • Humidity

[0054] • Type / batch of printing ink;

[0055] • Type / batch of the carrier material being printed;

[0056] • Pretreatment of the substrate material (e.g. by priming).

[0057] The properties of the printing parameters are state of the art and have already been described at the beginning. In this case, a set refers to a compilation of printing parameters, with each printing parameter having exactly one defined value or a defined variable. In one embodiment of the invention, a set of printing parameters comprises all of the named printing parameters or a selection thereof. In one embodiment of the present invention, several sets of printing parameters are provided. In principle, any number of sets of printing parameters can be provided. In one embodiment, 2 to 10, preferably 2 to 6, particularly preferably 2 to 4 sets of printing parameters are provided.

[0058] The processed digital decor raw data and the at least one set of printing parameters are transferred to a color management or RIP software and color space profiled production data for the at least one set of printing parameters are calculated from the processed digital decor raw data.

[0059] As already described, printing systems here are digital printers, either alone or in a system with additional devices, e.g., devices for priming and / or transporting substrates. The focus of the invention is on industrial-scale printing systems that operate with high volumes. On an industrial scale, systems at full capacity can easily print 10 million m 2 of substrates per year and more. Paper digital printing systems with a working width of 200 cm can produce 50 million m 2printed substrate or about 3,500 tons of paper per year and more. Digital plate printers produce at least 1 million m 2 printed substrate per year. Especially with such printing systems, it is important to minimize defective rejects as much as possible in order to save costs and thus increase the efficiency of the printing process. Furthermore, high-quality prints with high reproducibility are required.

[0060] The printing parameters determine, among other things, which digital printer should be used for printing. Different digital printers generally have different printing properties. In this step, a color space adjustment is carried out, whereby the color space-profiled production data is then no longer available in the RGB color space, but in a smaller, more restricted color space. When calculating the color space-profiled production data, the printing parameters take into account the color model used by the digital printer intended for printing. In one embodiment of the present invention, the color space-profiled production data is calculated in a color model selected from the group comprising CMYK, CRYK, 1-color, 5-color, 6-color, 7-color or 8-color color models. The color models can also contain spot colors.

[0061] The color space available during printing is also influenced by the other printing parameters mentioned above. This is known to those skilled in the art and has already been explained. By calculating the color-space-profiled production data, the influence of the printing parameters on the color space is taken into account. In this process step, the digital data is therefore clipped to the color space used in printing with a digital printer under defined printing parameters.

[0062] If multiple sets of printing parameters are provided, in one embodiment, color space-profiled production data is created for each set of printing parameters. According to the invention, the creation or calculation of the color space-profiled production data is based on the processed digital decor raw data. Consequently, the color space-profiled production data is always created based on the largest possible color space, namely the RGB color space.

[0063] According to the invention, separation data is calculated from the color-space-profiled production data calculated for the at least one set of printing parameters. The separation data is an assignment of the print data to the individual print heads of the digital printer. This procedure is known to those skilled in the art. In one embodiment, the separation data is calculated from the digital production data using color management, RIP software, or printer-internal software.

[0064] According to the invention, the processed digital image of the analogue decoration with the calculated separation data is output onto a carrier material by a digital printer, wherein the digital printer is comprised of the at least one set of printing parameters for which the colour space profiled production data were calculated.

[0065] According to the invention, a digital image of the analogue decoration with the separation data is output by at least one digital printer under the printing parameters defined in the at least one set of printing parameters. These printing parameters correspond to the printing parameters that formed the basis for calculating the color-space-profiled production data from which the separation data were calculated. The printing parameters that formed the basis for calculating the color-space-profiled production data and the separation data are therefore also used for printing.

[0066] According to the invention, the appearance of the printed decoration on the carrier material corresponds to the appearance of the processed digital image as represented by the processed raw decoration data.

[0067] In one embodiment of the invention, in method step vi., separation data are calculated from the color space-profiled production data calculated for each set of printing parameters, and in method step vii., a digital image of the analog decoration with the respectively calculated separation data is output onto a carrier material by a respective digital printer. In this case, each digital printer is included in the set of printing parameters for which the color space-profiled production data and the respective separation data were calculated. According to the invention, the color space-profiled production data and the separation data calculated therefrom are always calculated as belonging to a set of printing parameters, and a digital image is output using precisely those printing parameters and the calculated separation data.

[0068] Advantageously, this allows color-space-profiled production data and the resulting separation data to be calculated for printing with different printing parameters and thus for different digital printers. However, it is also possible, for example, to calculate color-space-profiled production data and the resulting separation data for printing with the same digital printer and color model, but on different substrates. The starting point in each case is the processed decorative raw data, which is available in the RGB color space. The color-space-profiled production data and the resulting separation data can thus always be calculated based on the largest possible color space.

[0069] According to the present invention, a graphics department can advantageously retouch the digital image of the analogue decor simply and quickly, thus saving costs, once in the RGB color space. There is no need to repeatedly edit the separation data, as is the case with prior art. Decor development times are thus shortened by several days to several weeks, which represents a tremendous competitive advantage. Furthermore, it enables faster response to customer requests.

[0070] Furthermore, the separation data no longer requires digital post-processing, as is common in the current state of the art. The raw digital decor data has already been digitally processed and thus already includes the desired retouching of the digital image of the analog decor. This can result in significant time savings and make the printing process more cost-effective.

[0071] In principle, any material suitable for applying a printing medium is suitable as a carrier material. The carrier material can have a smooth or rough surface onto which the printing medium is applied. In one embodiment of the invention, the carrier material according to the present invention is selected from a group comprising paper, glass, metal, foils, wood-based materials, plastics and combinations thereof, in particular medium-density fiberboard (MDF), high-density fiberboard (HDF), chipboard, oriented strand board (OSB), plywood and wood-plastic boards (WPG), veneers, lacquer layers, plastic boards, fiber-reinforced plastic, hard paper and inorganic carrier boards. In a preferred embodiment, the carrier material has at least one flat shape which can be printed with the printing plates according to the invention.Suitable substrates include laminates, furniture boards, furniture fronts, worktops, door panels, wallpaper, paper, and glass surfaces. The substrate can have a smooth or textured surface.

[0072] In one embodiment, the substrate can be pretreated. Pretreatment involves sanding the substrate and / or applying a primer. If the substrate is paper or wallpaper, pretreatment can also take the form of applying a primer.

[0073] In one embodiment of the present invention, at least one primer layer is applied to the side of the substrate to be printed prior to printing. Particularly when using wood-based panels as the substrate, in one embodiment of the present method, at least one primer layer comprising at least one resin and / or at least one varnish is applied to the side of the wood-based panel to be printed prior to printing with the digital image, which primer layer is then partially dried and / or partially cured.

[0074] Furthermore, the primer can contain at least one additive and / or at least one additive. Suitable additives are selected from the group consisting of hardeners, wetting agents (surfactants or mixtures thereof), and release agents. Suitable additives are selected from the group consisting of conductive substances and cellulose. The conductive substances can be selected from the group consisting of carbon black, carbon fibers, metal powder, and nanoparticles, in particular carbon nanotubes.

[0075] Preferably, the side of the substrate material to be printed, in particular a wood-based panel, is sanded before applying the primer.

[0076] For priming, an aqueous resin solution and / or a radiation-curable filler can be applied to the side of the substrate to be printed. Aqueous resin solutions such as melamine-formaldehyde resin, urea-formaldehyde resin, or melamine-urea-formaldehyde resin can be used as primers. It is also possible to pre-coat or prime the substrate with a 1K / 2K acrylic, UV, and / or EBH filler and then cure this primer layer accordingly.

[0077] Preferably, an aqueous resin solution is used for the pre-coating or priming of the carrier material, in particular a wood-based panel, which is an aqueous resin solution, in particular an aqueous solution of a melamine-formaldehyde resin, urea-formaldehyde resin or melamine-urea-formaldehyde resin.

[0078] The application quantity of liquid resin solution for priming can be between 10 and 80 g / m 2, preferably 20 and 50 g / m 2 The solids content of the aqueous resin solution is between 30 and 80%, preferably 40 and 60%, and particularly preferably 55%. The liquid resin may additionally contain suitable wetting agents, hardeners, release agents, and defoamers.

[0079] After applying the aqueous resin solution to the substrate for pre-coating or priming, the liquid resin is dried to a moisture content of 10%, preferably 6%, e.g. in a convection oven or near-infrared oven.

[0080] In another embodiment of the present method, the substrate material, in particular a wood-based panel, can be precoated or primed with a 1C / 2C acrylic and / or EBH filler. A UV filler advantageously consists essentially of UV-curable coating components, pigments, reactive thinners, and radical formers as chain initiators.

[0081] In this case, the amount of filler applied can be 50 to 150 g / m 2 , preferably 50 to 100 g / m 2 The quantities given refer to a 100% filler.

[0082] It is also possible that the filler used for priming is pigmented, which can vary or improve the printing result.

[0083] Particularly preferred according to the invention is the pre-coating of the carrier material with a transparent primer.

[0084] In a further embodiment of the present method, prior to printing on at least one side of the substrate material, in particular a wood-based panel, at least one layer of a pigmented primer, which is preferably water-based, is applied to the side of the substrate material to be printed. The pigmented primer can be applied either directly to the untreated surface of the substrate material or to the previous, preferably transparent, primer.

[0085] The water-based pigmented primer can also be applied in more than one layer (e.g., 3 to 10 layers, preferably 5 to 8 layers, particularly preferably 7 layers), with the pigmented primer being dried after each layer application, e.g., in a convection dryer or a near-infrared dryer. The water-based pigmented primer preferably contains at least one light-colored pigment, particularly preferably at least one white pigment.

[0086] White pigments are achromatic inorganic pigments with a high refractive index (greater than 1.8), which are primarily used to create optical whiteness in paints or as fillers in, for example, plastics. White pigments according to the invention can be selected from the group comprising titanium dioxide, lithopone, barium sulfate, zinc oxide, zinc sulfide, and calcium sulfate. Lithopone is a white pigment containing barium sulfate and zinc sulfide. According to the invention, titanium dioxide is preferably used as the white pigment in the water-based pigmented primer, since titanium dioxide has the highest refractive index and thus the highest hiding power among the known white pigments.

[0087] The substrate can therefore be primed before printing, and after printing, one or more protective layers, preferably one, two, or three, can optionally be applied. The at least one protective layer comprises abrasion-resistant particles, natural fibers, synthetic fibers, and / or other additives. Resins such as melamine-formaldehyde resin, urea-formaldehyde resin, acrylate resins, and polyurethane resins can be used as suitable binders.

[0088] The abrasion-resistant particles are preferably selected from the group consisting of aluminum oxides, corundum, boron carbide, silicon dioxide, silicon carbides, silanized corundum particles, and glass spheres. The application of abrasion-resistant particles and / or glass spheres can increase the wear resistance of a carrier material provided with a decoration and optionally a structure. Natural and / or synthetic fibers, in particular fibers selected from the group consisting of wood fibers, cellulose fibers, wool fibers, hemp fibers, and organic or inorganic polymer fibers, are used. Conductive substances, flame retardants, luminescent substances, and metals can be added as additives. The conductive substances can be selected from the group consisting of carbon black, carbon fibers, metal powder, and nanoparticles, in particular carbon nanotubes. Combinations of these substances can also be used.Phosphates, borates, especially ammonium polyphosphate, tris(tribromoneopentyl)phosphate, zinc borate, or boric acid complexes of polyhydric alcohols are preferred as flame retardants. Fluorescent and / or phosphorescent substances based on inorganic or organic materials, especially zinc sulfite and alkaline earth aluminates, are preferred as luminescent substances.

[0089] In one embodiment of the invention, paper is used as the carrier material. Paper suitable as a printing base paper is preferably white and has a weight of 60 to 90 g / m 2 , preferably 65 to 80 g / m 2 , particularly preferably 70 g / m 2 . In a further embodiment, the paper suitable as printing base paper is preferably white and has a weight of 50 to 90 g / m 2 , preferably 50 to 70 g / m 2 , particularly preferably 65 g / m 2 .

[0090] Before printing, the paper is coated with a primer to underline it. Suitable primers are known to those skilled in the art. In one embodiment, the primer comprises water as well as additives and / or additional substances. Preferably, the primer comprises up to 90% water. Suitable additives are selected from the group comprising hardeners, wetting agents (surfactants or mixtures thereof), and release agents. Suitable additives are selected from the group comprising conductive substances and cellulose. The conductive substances can be selected from the group comprising carbon black, carbon fibers, metal powder, and nanoparticles, in particular carbon nanotubes.

[0091] The application quantity of the primer is in one embodiment 3 to 20 g / m 2 , preferably 3 to 10 g / m 2 , particularly preferably 5 to 6 g / m 2 .

[0092] The present invention offers the advantage that the amount of primer used can be adapted to the decoration to be printed.

[0093] Printed decors are used, for example, in the production of flooring laminate or in the form of wall and ceiling paneling elements. In this case, the carrier material is preferably a wood-based panel. In one embodiment of the present invention, the carrier material is therefore a wood-based panel. In a further embodiment of the present process, the printed carrier material, optionally provided with a protective layer, in particular made of formaldehyde resins, is further processed or finished in a short-cycle press. In the short-cycle press, the resin layers are melted and the layer composite is cured to form a laminate. During further processing in the short-cycle press, surface structures can also be created in the surface of the carrier material, such as a wood-based panel, using a structured press plate. These structures can optionally be designed to match the decor (so-called decor-synchronous structure).In wood decors, the textures can take the form of pore structures that follow the grain. In many decors, the textures can be indentations or filling lines in the area of ​​joints encompassed by the decor.

[0094] In the following, the present invention is explained in more detail with reference to a figure and two exemplary embodiments.

[0095] Figure 1 shows a basic flow of the procedure.

[0096] Figure 1 illustrates a basic sequence of the method according to the invention. An analog decoration 10 is provided, of which a digital image is created by the device 20, which digital image is present in the form of raw decoration data 30. According to the invention, the device 20 can be, for example, a digital camera or a scanner. The digital raw decoration data 30 is processed and retouched on a PC 40, thereby producing processed raw decoration data 50. Three different sets of printing parameters 60-62 are provided. Color space profiled production data 70-72 are calculated from the processed raw decoration data 50 and a respective set of printing parameters 60-62. Separation data 80-82 are then calculated from the color space profiled production data 70-72, which are subsequently used for printing onto a carrier material 90-92.Printing takes place under the printing parameters used to calculate the color-space-profiled production data and the associated separation data. This means that the color-space-profiled production data 70 are calculated from the processed decor raw data 50 and the printing parameters 60. The separation data 80 are calculated from the color-space-profiled production data 70, and these separation data 80 are then used for printing on the carrier material 90 under the printing parameters 60. Advantageously, color-space-profiled production data 70-72 and separation data 80-82 can be generated for different sets of printing parameters 60-62, always starting from the processed decor raw data 50. The processed decor raw data 50 is available in the RGB color space and thus has the greatest possible information content after digitizing the analog decor 10.The color space profiled production data 70-72 and the separation data 80-82, however, are available for a color model such as the CMYK color model.

[0097] In the prior art, it is common practice to first generate separation data for specific printing parameters, which are then retouched, and then to calculate second separation data for other printing parameters from this first retouched separation data. The second separation data is derived from the first and is therefore also based on the color space in which the first separation data was calculated. The color space of the second printing parameters can therefore no longer be larger than the color space of the first printing parameters. This procedure can lead to losses in color information and thus in print quality if, for example, the first set of printing parameters includes a printer with a 4-color system and the second set of printing parameters includes a printer with a 5-color system.

[0098] Example 1

[0099] At a manufacturer of laminate flooring, decors were printed on three different digital printing systems for further processing into decorative panels. Thus, three different sets of printing parameters were available for printing on each of the three digital printing systems. First, a beechwood board was provided, of which a digital image was taken with a digital camera. The digital image was thus available in the form of digital raw decor data within the meaning of the invention. The digital raw decor data was retouched for sharpness and contrast, and processed raw decor data 50 was generated and calculated.

[0100] The three different digital printing systems included two identical paper digital printing systems for printing decorative paper rolls using a 4-color system (4-color printing). The third digital printing system was a digital printing system for printing primed wood-based panels using a 5-color system (5-color printing).

[0101] The color spaces were strongly influenced by the printing parameters. The white primer on the wood-based panels was significantly darker than the white paper, which meant that the color space for printing on the primed wood-based panel itself was initially smaller, even with otherwise identical printing parameters.

[0102] The substrate of the primed wood-based panel had a 3-4 lower L value than the white paper. This resulted in a color gamut that was at least approximately one-third smaller. The bright, vibrant colors would therefore not have been possible with a 4-color system (CYRK color system). To increase the color gamut, five colors (5-color system) were used when printing on the wood-based panel. The 5-color system used was C Y1 Y2 RK.

[0103] From the processed decor raw data 50, color space profiled production data 70-72 were calculated for the three different sets of print parameters 60-62, and thus for each of the three digital printing systems. The processed decor raw data and print parameters 60-62 were transferred to the RIP software of the respective digital printing systems. The color space profiled production data 70-72 for printing with the 4-color system were calculated based on the same digitally processed decor raw data as the color space profiled production data 70-72 for printing with the 5-color system.

[0104] The following are the three sets of printing parameters for which color space profiled production data 70-72 were calculated.

[0105] For printing, separation data 80-82 were calculated from the color-space-profiled production data 70-72. The printing of a digital image onto the substrate was carried out with high quality for all three sets of printing parameters. Furthermore, color-space-profiled production data 70-72 and the resulting separation data 80-82 for the various sets of printing parameters could be calculated quickly and efficiently. Changed printing parameters did not lead to delays in the calculation of the separation data, as these were always calculated based on the processed decorative raw data. As a result, the method according to the invention is more cost-effective than prior art methods.

[0106] If the separation data for printing with the 5-color system had been calculated from the separation data for printing with the 4-color system, as is common practice in the prior art, this would have been detrimental to the quality of the separation data for printing with the 5-color system. This would have been because the separation data would no longer have been calculated based on the largest possible color space (RGB color space, in which the digital production data is available), but rather based on a smaller color space.

[0107] Example 2

[0108] At a manufacturer of laminate flooring, decors were printed on two different digital printing systems for further processing into decorative panels. Two different sets of printing parameters were therefore available for printing on each of the two digital printing systems. First, a beechwood board was provided, of which a digital image was taken with a digital camera. The digital image was thus available in the form of digital raw decor data within the meaning of the invention. The digital raw decor data was retouched for sharpness and contrast, and processed raw decor data 50 was generated and calculated.

[0109] The two different digital printing systems comprised two identical paper digital printing systems on which rolls of decorative paper were printed using a 4-color system (4-color printing). White paper was used as the carrier material in each case, with a primer applied to the paper during one print run. The primer used was a primer containing 90% water and 10% additives and additives, with an application rate of 6 g / m². 2 used.

[0110] The color spaces were strongly influenced by the printing parameters. If the paper is printed without a primer, the printing ink penetrates unhindered into the rough surface of the paper. On the other hand, with primed paper, the additives and fillers in the primer prevent the printing ink from penetrating deeply into the surface of the paper. This allows a significantly wider color space to be reproduced, as the inks and their pigments adhere to the surface, thus enhancing the color impression, unlike if they were to sink into the paper.

[0111] From the processed decor raw data 50, color space profiled production data 70-72 were calculated for the two different sets of print parameters 60-62, and thus for each of the two digital printing systems. The processed decor raw data and print parameters 60-62 were transferred to the RIP software of the respective digital printing systems. The color space profiled production data 70-72 for printing with the 4-color system on the two digital printing systems were each calculated based on the same digitally processed decor raw data.

[0112] The following are the two sets of printing parameters for which color space profiled production data 70-72 were calculated.

[0113] For printing, separation data 80-82 were calculated from the color-space-profiled production data 70-72. Printing a digital image onto the substrate was performed with high quality for both sets of printing parameters. Furthermore, color-space-profiled production data 70-72 and the resulting separation data 80-82 for the various sets of printing parameters could be calculated quickly and efficiently. Changed printing parameters did not lead to delays in calculating the separation data, as these were always calculated based on the processed decorative raw data. As a result, the method according to the invention is more cost-effective than prior art methods. List of reference symbols

[0114] 10 analog decor

[0115] 20 Device for creating a digital image

[0116] 30 decorative raw data

[0117] 40 PC for retouching

[0118] 50 processed decorative raw data

[0119] 60-62 Set of printing parameters

[0120] 70-72 color space profiled production data

[0121] 80-82 Separation data

[0122] 90-92 carrier material

Claims

Claims 1. A method for digitally printing a decoration onto a substrate with at least one set of defined printing parameters, characterized in that the method comprises the steps: i. providing an analog decoration; ii. generating and storing at least one digital image in the form of digital decoration raw data in the RGB color space from the analog decoration; iii. digitally processing at least a part of the digital decoration raw data in the RGB color space and generating processed digital decoration raw data; iv. providing at least one set of printing parameters; v. transferring the processed digital decoration raw data and the at least one set of printing parameters to color management or RIP software and calculating color space-profiled production data for the at least one set of printing parameters from the processed digital decoration raw data; vi.Calculation of separation data from the color space-profiled production data calculated for the at least one set of printing parameters; vii. Output of a digital image of the analog decor with the calculated separation data by a digital printer onto a substrate, wherein the digital printer is included by the at least one set of printing parameters for which the color space-profiled production data were calculated; wherein the printing parameters in process step iv. include the type of printing equipment, the color model to be used for printing, the temperature, the humidity, the printing ink, and the type of substrate.

2. Method according to claim 1, characterized in that the carrier material is selected from a group comprising paper, glass, metal, foils, wood-based materials, plastics and combinations thereof.

3. Method according to one of the preceding claims, characterized in that in method step ii. the digital decor raw data are generated by photographing the analog decor with a digital camera or by scanning the analog decor with a scanner.

4. Method according to one of the preceding claims, characterized in that in method step iii. during the digital processing of at least a part of the decor raw data, these are retouched. The method according to claim 4, characterized in that during retouching • the color tone of at least part of the decor raw data is changed; and / or • the brightness of at least part of the decor raw data is changed; and / or • the saturation of at least part of the decor raw data is changed; and / or • the contrast of at least part of the decor raw data is changed; and / or • the sharpness of at least part of the decor raw data is changed. Method according to one of the preceding claims, characterized in that in process step iii, part or all of the decor raw data is digitally processed. Method according to one of the preceding claims, characterized in that the processing of at least part of the digital decor raw data in process step iii is carried out using Adobe Photoshop software. Method according to one of the preceding claims, characterized in that the printing parameters in process step iv further include the pretreatment of the substrate material. Method according to one of the preceding claims, characterized in that in process step v, color space-profiled production data is calculated for more than one set of printing parameters. Method according to claim 9, characterized in that in process step vi.Separation data is calculated from the color space-profiled production data calculated for each set of printing parameters, and in process step vii, the digital image of the analog decoration with the respective calculated separation data is output onto a substrate by a digital printer, wherein each digital printer is comprised of the set of printing parameters for which the color space-profiled production data and the respective separation data were calculated. A method according to one of the preceding claims, characterized in that the substrate is primed before printing. A method according to any one of the preceding claims, characterized in that the substrate material is provided with a protective layer after printing. A method according to any one of the preceding claims, characterized in that the substrate material is fed to a KT press after printing. A method according to claim 13, characterized in that the printed substrate material is provided with a surface structure in the KT press.

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