Method of manufacturing decorative panel

Abstract

The invention relates to a method for manufacturing a decorative panel. A method of manufacturing a decorative panel and a system for manufacturing a decorative panel comprising the steps of: inkjet printing a first decorative layer (301) in a web inkjet printing system for a first period of time; and in a second time period, inkjet printing a second decorative layer in the web inkjet printing system (302); hot-pressing the first decorative layer (301) into a decorative panel (331) on a first hot press (401); and hot-pressing the second decorative layer (302) into another decorative panel (332) on a second hot press (402); and wherein the first time period and the second time period overlap.

Description

[0001] This application is a divisional application of parent application number 201980018284.8. The parent application was filed on February 25, 2019; the invention is entitled "Method for Manufacturing Decorative Panels". Technical Field

[0002] This invention relates to the manufacture of decorative panels, wherein a decorative image (such as a wood pattern) is printed on a substrate using a roll-to-roll inkjet printing system to form a decorative layer, and then the decorative layer is thermopressed together with one or more other layers using a thermosetting resin to form a decorative panel; it can be cut into multiple decorative laminates. Such decorative panels and decorative laminates are primarily used for decorative flooring, decorative wall elements, and decorative furniture. Background Technology

[0003] Gravure, offset, and flexographic printing are increasingly being replaced by industrial inkjet printing systems for various applications. These industrial inkjet printing systems have now proven their flexibility in use, such as variable data printing, which enables short production runs and personalized products, as well as their enhanced reliability, which allows for integration into production lines.

[0004] Inkjet technology has also been implemented by manufacturers of decorative panels such as laminate flooring. A historical overview and specific case studies of roll-to-roll inkjet printing systems used to print decorative images on decorative paper to manufacture decorative panels are published. Patrik Lutz Chapter 44, "Industrial Inkjet Printing in Decorative Web Print Applications," and Aliasgar Eranpurwala Chapter 48, “Hymmen Digital Décor Printing: Empowering the Laminate Industry,” in “Handbook of Industrial Inkjet Printing: A Full System Approach,” edited by Werner Zapka (published by Wiley-VCH Verlag GmbH & Co., 22 / 11 / 2017, 984 pages).

[0005] Multi-pass inkjet printers are also used as roll-to-roll inkjet printing systems for manufacturing decorative panels. This is disclosed, for example, in the following published European patent application EP2905145 A1 (UNILIN BVBA), in which a multi-pass inkjet system for manufacturing decorative panels is disclosed in paragraph

[0024] .

[0006] Some decorative panels must be manufactured using a hot press with a specific construction (e.g., dimensions, embossing, heating temperature, addition of extra layers such as a protective layer), while other decorative panels must be manufactured using a hot press with a different construction. To avoid switching between constructions, more than one hot press can be used in the decorative panel production line.

[0007] To prevent decorative layers containing inkjet-printed patterns from being incorrectly manufactured due to improper construction of the hot press, a solution is needed that avoids such waste and downtime caused by such incorrect allocation of the hot press. Similarly, a solution is needed to prevent, for example, decorative layers from being assigned to incompatible hot presses due to their dimensions.

[0008] One solution is to have more than one roll-to-roll inkjet printing system available in the decorative panel production line. However, this is an uneconomical solution. For example, Hymmen uses CMYK inkjet inks. TM The Jupiter JPT-W printer contains over 200 inkjet printheads to cover a width of 2.20 m, making it a very expensive machine. In addition, there are additional room space requirements, higher energy costs, greater need for additional exhaust gas extraction capabilities, and operator requirements for each roll-to-roll inkjet printing system, among others.

[0009] Due to the new possibilities of personalized decorative panels, very short turnaround times are expected, making such solutions more necessary than ever before. Such hot presses can be located far from the roll-to-roll inkjet printing system, and therefore, misassignment of such hot presses should be avoided to prevent limiting the manufacturing time of decorative panels, especially for personalized panels, such as those with printed company names and logos, or on-demand decorative panels, which are for single or small-batch orders, requiring a fast and smooth production process. Summary of the Invention

[0010] It has been found that the aforementioned problems can be overcome by using a web-based inkjet printing system for inkjet printing a first decorative layer and a second decorative layer in an overlapping time period, and for assigning the first decorative layer to a first hot press and the second decorative layer to a second hot press. By printing the first and second decorative layers in an overlapping time period (e.g., simultaneously or partially simultaneously), the manufacturing time of the decorative panels (331, 332) can be shortened, and this is achieved using only one economically viable web-based inkjet printing system.

[0011] A preferred embodiment of the present invention has been implemented using the decorative panel manufacturing method as defined in claim 1. A preferred embodiment of the present invention has been implemented using the decorative panel production line as defined in claim 9. Attached Figure Description

[0012] Figure 1 This section describes a production line for a decorative panel as a preferred embodiment of the present invention. This section relates to inkjet printing of a first decorative layer (301) and a second decorative layer (302) as described in the present invention. A roll-to-roll inkjet printing system is illustrated as a side view (I) and a corresponding cross-section (II). The roll-to-roll inkjet system is part of a production line, which is not fully described, comprising a first roll of paper substrate on a first unwinding roller (101) and a second roll of paper substrate on a second unwinding roller (102). The second unwinding roller (102) is not visible in the side view of the roll-to-roll inkjet system. Both unwinding rollers are attached to a shaft (95) that rotates while conveying the two rolls of paper substrate below an inkjet printhead unit (500). A decorative image is formed on the first roll of paper substrate and another decorative image is formed on the second roll of paper substrate by spraying ink droplets (505) onto the first and second rolls of paper substrate. The two decorative images are printed in overlapping time periods. During transport and printing, the first and second rolls of paper substrate are supported by a printing table (200). A first decorative layer (301) is wound around a first winding roller (701), and a second decorative layer (302) is wound around a second winding roller (702). The two winding rollers are rotatably attached to separate shafts (95). Arc-shaped arrows indicate the direction of rotation of the rollers.

[0013] Figure 2 This section describes a production line for a decorative panel as a preferred embodiment of the present invention. This section relates to inkjet printing of a first decorative layer (301) and a second decorative layer (302) as described in the present invention. A roll-to-roll inkjet printing system is illustrated as a side view (I) and a corresponding cross-section (II). The roll-to-roll inkjet system is part of a production line, which is not fully described, comprising a roll-to-roll substrate on a unwinding roller (101). The unwinding roller is attached to a shaft (95) that rotates while conveying the roll-to-roll substrate below an inkjet printhead unit (500). A decorative image is formed on the roll-to-roll substrate by spraying ink droplets (505) onto the second roll-to-roll substrate, and another decorative image is formed on the roll-to-roll substrate. The two decorative images are printed in overlapping time periods. The roll-to-roll substrate is supported by a printing table (200) during both conveying and printing. A roll of paper substrate is cut into strips by a slitter (600, symbol for scissors) to form a first roll of paper substrate with a first decorative layer (301) and a second roll of paper substrate with a second decorative layer (302). The first decorative layer (301) is wound on a first winding roller (701), and the second decorative layer (302) is wound on a second winding roller (702). The two winding rollers are rotatably attached to separate shafts (95). Arc arrows indicate the direction of rotation of the rollers.

[0014] Figure 3 Explanation in Figure 1 or Figure 2 This is part of the production line following section (1000) described in the diagram. The first winding roller (701) containing the first decorative layer (301) is... (a1) Unwound; (b1) Impregnated with resin by a resin impregnation machine (800); (c1) The first sheet-shaped resin-impregnated decorative layer (311) is cut by a sheet cutter (605); (d1) The core layer (321) is supplied to the first sheet-like resin-impregnated decorative layer; (e1) Hot pressing is performed by the first hot press (401); (f1) After hot pressing, a decorative panel (331) containing a first decorative layer (301) is formed: (g1) A panel cutting machine (850) cuts a decorative panel (311) into multiple decorative laminates (341).

[0015] The second winding roller (702) containing the second decorative layer (302) is (a2) unwound; (b2) Impregnated with resin by another resin impregnation machine (800); (c2) Cut into a second sheet-like resin-impregnated decorative layer (312) by a sheet cutter (605); (d2) The core layer (322) is supplied to the second sheet-like resin-impregnated decorative layer; (e2) Hot pressing is performed using a second hot press (402); (f2) After hot pressing, a decorative panel (332) containing a second decorative layer (302) is formed: The dashed arrows indicate several steps in the production line from (a1) to (g1) or from (a2) to (f2). The first hot press (401) has a certain size, and the length of the thick arrow indicates the pressure during hot pressing, while the second hot press (402) has a different size because the second decorative layer (302) has a different width / length than the first decorative layer (301) and the pressure during hot pressing is lower. The curved arrows indicate the direction of rotation of the rollers.

[0016] Figure 4 This is the preferred implementation scheme, which does not use, for example Figure 1 , Figure 2 and Figure 3 The winding rollers (701, 702) in the middle. Figure 4This describes a production line for a decorative panel as a preferred embodiment of the present invention. This part includes inkjet printing of a first decorative layer (301) and a second decorative layer (302) as in the present invention. The roll-to-roll inkjet printing system is illustrated only by side view (I). Cross-sections are derived from the preceding views and are therefore not shown. The roll-to-roll inkjet system is part of a production line, which is not fully described, that includes a first roll-to-roll substrate on a first unwinding roller (101) and a second roll-to-roll substrate on a second unwinding roller (102). The second unwinding roller (102) is not visible in the side view of the roll-to-roll inkjet system. Both unwinding rollers are attached to a shaft (95) that rotates while conveying the two roll-to-roll substrates below the inkjet printhead unit (500). A decorative image is formed on the first roll-to-roll substrate and another decorative image is formed on the second roll-to-roll substrate by spraying ink droplets (505) onto the first and second roll-to-roll substrates. The two decorative images are printed in overlapping time periods. During transport and printing, the first and second rolls of paper substrate are supported by the printing table (200). The first roll of paper substrate, which includes the first decorative layer, is... (b1) Impregnated with resin by a resin impregnation machine (800); (c1) The first sheet-shaped resin-impregnated decorative layer (311) is cut by a sheet cutter (605); (d1) The core layer (321) is supplied to the first sheet-like resin-impregnated decorative layer; (e1) Hot pressing is performed by the first hot press (401); (f1) After hot pressing, a decorative panel (331) containing a first decorative layer (301) is formed: (g1) A panel cutting machine (850) cuts a decorative panel (311) into multiple decorative laminates (341).

[0017] The second roll paper substrate containing the second decorative layer is (b2) Impregnated with resin by another resin impregnation machine (800); (c2) Cut into a second sheet-like resin-impregnated decorative layer (312) by a sheet cutter (605); (d2) The core layer (322) is supplied to the second sheet-like resin-impregnated decorative layer; (e2) Hot pressing is performed using a second hot press (402); (f2) After hot pressing, a decorative panel (332) containing a second decorative layer (302) is formed: The dashed arrows indicate several steps in the production line from (a1) to (g1) or from (a2) to (f2). The first hot press (401) has a certain size, and the length of the thick arrow indicates the pressure during hot pressing, while the second hot press (402) has a different size because the second decorative layer (302) has a different width / length than the first decorative layer (301) and the pressure during hot pressing is lower. The curved arrows indicate the direction of rotation of the rollers. Detailed Implementation

[0018] This invention includes the following embodiments: A method for manufacturing decorative panels (331, 332) includes the following steps: —During the first time period, the first decorative layer (301) is inkjet printed in the roll-to-roll inkjet printing system; and —During the second time period, a second decorative layer (302) is inkjet printed in the web inkjet printing system; and —The first decorative layer (301) is hot-pressed into a decorative panel (331) on a first hot press (401); and —The second decorative layer (302) is hot-pressed into another decorative panel 332 on a second hot press (402); and The first time period and the second time period overlap.

[0019] The roll-to-roll inkjet printing system can be operated by only one person per transfer. It has also been found that by using the method of the present invention, there is less waste of unprinted roll-to-roll substrate on which decorative images are printed to form the first decorative layer and / or the second decorative layer (302). The substrates of the first decorative layer (301) and the second decorative layer (302) can be different, for example: the first decorative layer (301) for high-end decorative panels and the second decorative layer (302) for low-end decorative panels, wherein, for example, a cheaper roll-to-roll substrate or a roll-to-roll substrate with a less thick primer is used. If demand is low, the roll-to-roll inkjet printing system can still be used by inkjet printing only one decorative layer in a given cycle with lower requirements. The present invention makes the roll-to-roll inkjet printing system versatile and easy to integrate, resulting in the manufacturing method of the present invention becoming universal in its use. It can be applied to many different methods of manufacturing decorative panels (331, 332) and to many different sizes of decorative panels (331, 332). This results in more than two decorative layers, and correspondingly more than two hot presses.

[0020] The inkjet printing of the first and second decorative layers (302) is performed by a web-based inkjet printing system. In this printing method, the web-based inkjet printing system ejects ink droplets from an inkjet printhead onto a web-based substrate, thereby forming a decorative image from the ejected ink. Decorative imagesDecorative patterns are preferred, such as wood patterns, stone patterns, or imaginative repeating patterns, but wood patterns (e.g., hardwood patterns, oak patterns, teak patterns) are most preferred. Decorative images are also preferred. oligochromatic images An image having a few (= few, ὀλίγοι) colors (color). Therefore, it is not a monochrome image (which is an image having one (= monochrome) color), and therefore not a multicolor image (which is an image having multiple colors, such as a photographic image with natural landscape content). The decorative layer may contain multiple copies of the same decorative image and / or at least one or more copies of two decorative images. These copies are preferably arranged according to a template, also called a layout or arranged by a nesting method, as disclosed in WO 2015 / 117944 (AGFA GRAPHICS NV, UNILIN BVBA). Typically, one or more decorative images (whether or not the same decorative image) used for printing the decorative layer are stored in the printing job, thereby storing, for example, the number of copies, and the memory allocation of one or more decorative images.

[0021] Web paper refers to the rolls (or "web paper") used to supply substrate to the printing press. The substrate, also known as web paper substrate, becomes a decorative layer (301, 302) once the decorative image is inkjet printed on it. This decorative layer can be heat-pressed with other layers (e.g., core layer (321, 322); protective layer, balancing layer) to form a decorative panel. Pressing is preferably performed at up to 25 bar or up to 100 N / cm. 2 The pressure and preferably temperature up to 200°C are applied. The hot press is, for example, a short-cycle press, such as those manufactured by Wemhoener. TM Surface Technologies GmbH & Co. KG (http: / / www.wemhoener.de / en / systems / short-cycle-press-lines) manufactures or dual-belt presses such as Hymmen. TM MFC Double BeltPress.

[0022] Before supplying one or more sheets to the hot press, the first decorative layer and / or the second decorative layer (301, 302) can be cut into one or more sheets, a method known as the roll-to-sheet method, or more preferably, they can be rolled up again as output rolls before being supplied to the hot press (where they are unrolled), a method known as the roll-to-roll method. Figure 3One or more sheets or output rolls may be supplied to the first hot press (401) and the second hot press (402), respectively. Most preferably, the first decorative layer and / or the second decorative layer may also be supplied directly from the web inkjet printing system to the first hot press (401) and the second hot press (402), respectively, regardless of whether they are first cut into sheets.

[0023] The location of the first hot press / second hot press (401, 402) may be different or remote from the following: web-based inkjet printing system and / or second hot press / first hot press (401, 402). Remote location means that the first hot press (401) is located at another address, such as a street further away, another city, or even another country.

[0024] In a preferred embodiment, the web-based inkjet printing system is Multi-pass inkjet printing system for roll paper This means that the decorative image contained in the first / second decorative layer (301, 302) is printed on the substrate in multiple passes from one or more inkjet printheads, preferably three or four passes, and most preferably two passes. Existing single-pass inkjet printing systems still suffer from major and minor operational failures. The major operational failure is when the single-pass inkjet printing system cannot print due to technical malfunction, and the production line for the decorative panels (331, 332) must be stopped. The minor operational failure is when some nozzles from the inkjet printhead fail to eject ink, resulting in line artifacts in the printed image and material waste after hot pressing by the cumbersome removal of these defective decorative panels (331, 332). Another problem is that despite the potential for infinitely variable printing in inkjet printing, issues arise with data flow to single-pass inkjet printing systems. The variable images to be printed require such high computational power that limitations on image variability must be implemented.

[0025] The reason why some decorative layers must be hot-pressed by one hot press rather than another may be due to the construction differences between the two hot presses, such as the size of the hot press, the maximum size of the layer that can be hot-pressed in the hot press, the inclusion of embossed plates with specific reliefs in the hot press, the minimum / maximum heat temperature of the hot press, the addition of additional layers (such as protective layers) at the hot press, the location of the hot press, and so on.

[0026] The appropriate hot press allocation for a decorative layer can depend on the content of the decorative image and / or its metadata, including, for example, the size of the decorative image, the type of embossed structure, or even the address of the requester manufacturing the decorative panel. For instance, spraying a dark decorative image with a large amount of ink may cause delamination after hot pressing at a certain temperature (<t0). If the first hot press (401) is unable to generate such a temperature during hot pressing, but the second hot press (402) has additional heat power to achieve a higher temperature (greater than t0) during hot pressing, it is preferable to allocate it to a decorative layer containing a dark decorative image to avoid subsequent delamination during the manufacture of the decorative panel. Another example is the allocation of a small, elongated decorative image to a hot press capable of hot pressing a small, elongated decorative layer containing such an image. Allocating a hot press that is too large may waste too much heat energy and should be avoided for both economic and ecological reasons.

[0027] In a preferred embodiment, the web-based inkjet printing system is Twin roll paper printing press It includes a first roll paper substrate for inkjet printing a first decorative layer (301) and a second roll paper substrate for inkjet printing a second decorative layer (302). Figure 1 , Figure 4 The preferred roll-to-roll inkjet printing system uses a first roller and a second roller, the first roller being used to inkjet print a first decorative layer (301) by supplying a first substrate from the first roller, and the second roller being used to inkjet print a second decorative layer (302) by supplying a second substrate from the second roller.

[0028] In another preferred embodiment, after inkjet printing, the web inkjet printing system cuts the web substrate into strips comprising a first web substrate including a first decorative layer (301) and a second web substrate including a second decorative layer (302). Figure 2 Cutting is performed using a slitting machine. Such a slitting machine contains razor blades or circular blades. An advantage of such a slitting machine is that it can be positioned according to the width of the decorative layer. In such a roll-to-roll inkjet printing system, the width of the decorative layer or roll-to-roll substrate is determined along a direction perpendicular to the transport direction of the roll-to-roll substrate and the decorative layer. The roll-to-roll substrate can be cut (also called slitting) into multiple smaller roll-to-roll substrates of variable width. Each cut smaller roll-to-roll substrate can be supplied to another thermopress, which is capable of processing (=thermally pressing) the smaller roll-to-roll substrates according to the dimensions (width and length) of the decorative layer. For example, in flooring, not only flooring elements are used, but also very small bases are used, thereby allowing small, elongated decorative layers to be printed as intermediate products during the manufacturing process. Depending on the roll-to-roll substrate, a laser-based slitting system can also be used.

[0029] The present invention also includes Roll-to-roll inkjet printing system for manufacturing decorative panels The implementation plan includes: —Multiple printheads for inkjet printing water-based coloring inkjet inks and / or coloring free radical-curable inks; and A first and a second roll of paper substrates have one or more ink-receiving layers on their surfaces to be printed with water-based inkjet inks. The first and second rolls of paper substrates are preferably paper, more preferably paper with a porosity between 8 and 20 seconds according to the Gurley method (DIN 53120). In this invention, previously disclosed preferred embodiments of the roll-to-paper inkjet printing system are also preferred embodiments of this roll-to-paper inkjet printing system. The roll-to-paper inkjet printing system is preferably controlled by a workflow system, such as for managing printing jobs, driving inkjet printheads, controlling the temperature at the printheads, controlling the drying performance of the roll-to-paper inkjet printing system, etc. Multiple printheads may be included in the inkjet printing unit. The inkjet ink is preferably part of an inkjet ink kit.

[0030] The present invention also includes Workflow system for manufacturing decorative panels Another embodiment of a workflow method for manufacturing decorative panels (331, 332) executed by this workflow system includes the following steps: managing multiple printing jobs for printing decorative images via a web-based inkjet printing system; wherein the multiple printing jobs comprise: —A first printing operation, the first printing operation comprising identifying a first decorative image and a first position, to heat-press a printed copy of the first decorative image at the first position into a first decorative panel; and —A second printing operation, the second printing operation including the identification of a second decorative image and a second position, to heat-press a printed copy of the second decorative image into a second decorative panel at the second position. The first position and / or the second position is preferably a remote position.

[0031] The printed copy of the first printing operation is the first decorative layer (301) of the present invention in the method for manufacturing decorative panels (331, 332). The printed copy of the second printing operation is the second decorative layer (302) of the present invention in the method for manufacturing decorative panels (331, 332).

[0032] Prior to the hot pressing step, it is preferable to add one or more layers (e.g., core layers (321, 322); protective layers, balancing layers) to the decorative layer, which are then hot-pressed together in a hot press to form a decorative panel. Such a workflow system is further disclosed and explained in more detail in the section on "Deco Workflow System".

[0033] The management process preferably includes the following additional steps: —Assigning the first printing job to the first printing area on the web inkjet printing system; and —Assign the second printing job to the second printing zone on the web inkjet printing system; and —In a first cycle, inkjet print a first print job in a first printing area, and in a second cycle overlapping with the first cycle, inkjet print a second print job in a second print job; and more preferably, additional steps: —Supplying a printed copy from a first inkjet printing job to a first position; and supplying a printed copy from a second inkjet printing job to a second position. The supply may include the step of conveying or delivering the printed copy to a position. The inkjet printing of the first and second printing jobs may be multi-pass inkjet printing, wherein the web-based inkjet printing system is a web-based multi-pass inkjet printing system.

[0034] The first printing area preferably does not overlap with the second printing area to prevent the two printing operations from being printed on top of each other. The size of the printing area can be adjusted according to the size of the decorative panel (331, 332) and / or the size of the hot press (401, 402).

[0035] In this invention, the previously disclosed preferred embodiments for the manufacture of decorative panels (331, 332) are also preferably embodiments for the aforementioned workflow system. The workflow system preferably controls the web-based inkjet printing system, not only managing the printing operation but also driving the inkjet printhead, controlling the temperature at the printhead, controlling the slitter in the printing system (e.g., changing its position via a driver), controlling the drying performance of the printing system, and so on.

[0036] The dimensions (width and / or length) of the printing zone depend on the dimensions of the assigned hot press, thus ensuring that inkjet printing jobs are dimensionally correct for supply to the assigned hot press. The printing zone is not a separate support for the roll paper substrate. The support can be divided into multiple virtual printing zones, one for a first printing job and another for a second printing job. For example, a printing job can be assigned to a specific printing zone by managing the printing job to allocate the correct hot press, based on the printing job's metadata. The length of the printing zone is measured parallel to the transport direction of the roll paper substrate. The width of the printing zone is measured perpendicular to the transport direction of the roll paper substrate.

[0037] The first and / or second printing jobs may also include identifying how the decorative panel must be cut or how the decorative panel must be embossed, regardless of whether it is digital embossing. The printing jobs may also include content representing an image of the relief used in the digital embossing system. WO16050372 (AGFA GRAPHICS NV) discloses a method for manufacturing digitally embossed panels for manufacturing decorative panels (331, 332).

[0038] The workflow system preferably includes calculation steps for determining the availability of web paper substrates in a web inkjet printing system.

[0039] Roll-to-roll inkjet printing system The roll-to-roll inkjet printing system includes means for conveying roll-to-roll paper substrate, on which multiple inkjet printheads are used to print decorative images. The multiple inkjet printheads are preferably contained in an inkjet printhead unit (500), and more preferably include an inkjet ink kit for printing color decorative images, which are preferably oligochrome images, and more preferably wood patterns.

[0040] The web-based inkjet printing system includes means for conveying more than one web substrate for printing multiple decorative layers. The more than one web substrate can be a strip of printed web substrate, more preferably unwound, and is thus supported at the input of the web-based inkjet printing system at each of the rollers from the substrate.

[0041] Rolls containing the paper roll substrate are mounted on a paper roll supply, which executes one or more spindles. The spindles are rotated by a drive mechanism that distributes torque from the drive shafts. The spindles are coaxial shafts used to hold the rolls containing the paper roll substrate. The spindles are also referred to as shafts (95).

[0042] It is preferable to use more than one spindle (one spindle per roll of paper substrate) to easily load and unload the rollers containing the rolls of paper substrate individually. The operator of the roll-to-roll inkjet printing system can then load one roller on each spindle. The more than one spindle can be connected to each other via a differential known in the automotive industry. Such a differential is a gear train with three shafts, having the property that the rotational speed of one shaft is the average speed of the other shafts or a fixed multiple of that average speed. The drive mechanism is preferably a motor that rotates the power transmission system within the spindle. Goldenrod TM The Corporation provides such equipment for winding and unwinding substrates on and from rollers. Such processing of shafts and rollers is known in the prior art.

[0043] Web-based inkjet printing systems preferably include a drying unit for drying the decorative images printed by the inkjet printing. The drying unit, such as a radiation curing unit or an infrared dryer, depends on the type of ink kit used in the web-based inkjet printing system.

[0044] The decorative layer can be conveyed to the first or second hot press (402) via one or more connection stations and / or one or more conveyor tables and / or one or more conveyor modules, up to the assigned hot press. The decorative layer can be supplied in the fully automated laying area before it enters, regardless of whether other layers, such as core layers (321, 322), are present. After hot pressing, the decorative panels can be supplied to the stacking area.

[0045] Web-based inkjet printing systems preferably include web guiding and / or web substrate unfolding devices for providing linear transport beneath multiple inkjet printheads. Due to poor color registration, web substrate wobbling and web movement can cause color deviations in the decorative layer.

[0046] The ability to rapidly change between printing jobs and to prioritize them among them allows the roll-to-roll inkjet printing system of this invention to be used as a proofing machine for decorative panels (331, 332) before mass production can begin using conventional printing systems (gravure printing, offset printing, and flexographic printing). Decorators and decorative image designers now have the possibility of quickly obtaining samples of newly created decorative panels.

[0047] A web-based inkjet printing system includes a printing table (200) for supporting the web-based substrate without wrinkling beneath the inkjet printhead unit. The printing table (200) can be a vacuum table for better holding the web-based substrate during printing in a multi-pass web-based inkjet printing system. The printing table (200) can also be a conveyor belt, thereby supporting the web-based substrate and preferably pressing it under vacuum. When vacuum power is used to press the web-based substrate, the conveyor belt is also called a vacuum belt. The principles of conveyor belts, vacuum belts, printing tables (200), and vacuum tables are known to those skilled in the art.

[0048] Production line for decorative panels The roll-to-roll inkjet printing system is preferably part of a production line for decorative panels (331, 332); thus, the production line for decorative panels (331, 332) includes: —A web-based inkjet printing system for manufacturing decorative panels (331, 332), comprising a plurality of printheads for inkjet printing using a water-based coloring inkjet ink cartridge; and a first web substrate and a second web substrate having one or more ink receiving layers on their surfaces to be inkjet printed with water-based coloring inkjet ink; and —A first resin impregnation machine (800) for impregnating a first decorative layer (301) with resin, the first decorative layer comprising a first roll paper substrate and a first decorative image ejected through a plurality of printheads; and a first hot press (401) for hot pressing the first decorative layer (301); —A second resin impregnation machine (800) for impregnating a second decorative layer (302) with resin, the second decorative layer comprising a second roll paper substrate and a second decorative image ejected through a plurality of printheads; and a second hot press (402) for hot pressing the second decorative layer (302); Preferably, one or more ink receiving layers include an outermost ink receiving layer, which is free of inorganic pigments or contains a smaller amount of inorganic pigments than the ink receiving layer between the web substrate and the outermost ink receiving layer.

[0049] The first resin impregnation machine (800) preferably uses a resin selected from melamine-formaldehyde resin, urea-formaldehyde resin and phenol-formaldehyde resin to impregnate the first decorative layer (301).

[0050] The preferred ink kit includes red inkjet inks containing pigments selected from CI Pigment Red 254, CI Pigment Red 176 and CI Pigment Red 122 or mixtures thereof.

[0051] Preferably, the first decorative layer (301) is hot-pressed together with the core layer (321, 322) and the protective layer to form a decorative panel; wherein the core layer (321, 322) is selected from MDF, HDF or OSB.

[0052] The present invention also includes the following embodiments: A method for manufacturing decorative panels (331, 332) includes the following steps: —During the first time period, the first decorative layer (301) is inkjet printed in the roll-to-roll inkjet printing system; and —During the second time period, a second decorative layer (302) is inkjet printed in the web inkjet printing system; and —The first decorative layer (301) is impregnated with resin using a first resin impregnation machine (800); and —The second decorative layer (302) is hot-pressed by a second resin impregnation machine (800); and The first time period and the second time period overlap. Therefore, the decorative layer (301, 302) preferably comprises a paper substrate as defined below in "Paper Substrate for Decorative Panels".

[0053] The resin is preferably selected from melamine-formaldehyde resin, urea-formaldehyde resin, and phenol-formaldehyde resin. This preferred embodiment has the same inventive concept as the manufacturing process achieved by the first and second hot presses. This is a solution to the same problem in the manufacturing method utilizing the first and second hot presses.

[0054] Similarly, the roll-to-roll inkjet printing system can be operated by only one person per transfer. It has also been found that by using the method of the present invention, there is less waste of unprinted roll-to-roll substrate on which decorative images are printed to form the first decorative layer and / or the second decorative layer (302). The substrates of the first decorative layer (301) and the second decorative layer (302) can be different, for example: the first decorative layer (301) for high-end decorative panels and the second decorative layer (302) for low-end decorative panels, wherein, for example, a cheaper roll-to-roll substrate or a roll-to-roll substrate with a less thick primer is used. If demand is low, the roll-to-roll inkjet printing system can still be used by inkjet printing only one decorative layer in a given cycle with lower requirements. The present invention makes the roll-to-roll inkjet printing system versatile and easy to integrate, resulting in the manufacturing method of the present invention becoming universal in its use. It can be applied to many different methods of manufacturing decorative panels (331, 332) and to many different sizes of decorative panels (331, 332). This results in more than two decorative layers, and correspondingly more than two resin impregnation machines. When applying resin in the resin impregnation machine (800), the resin thickness can be varied by controlling the resin impregnation machine (800), for example, by applying an impregnation roller with greater pressure towards the paper substrate. For example, for decorative panels in which a post-forming step is applied, less resin is used in the impregnation step.

[0055] The reason why some decorative layers must be impregnated by resin rather than by another resin impregnation machine (800) may be due to the construction differences between the two resin impregnation machines, such as the size of the resin impregnation machine, the maximum size of the layer that can be impregnated in the resin impregnation machine, the minimum / maximum applicable thickness of the resin impregnation machine, the addition of additional layers (such as another resin), the location of the resin impregnation machine, etc.

[0056] Methods of resin impregnating decorative layers with resin are well known in the art, as exemplified by WO2012 / 126816 (VITS) and EP 966641 (VITS).

[0057] Web paper refers to the roll (or "web paper") used to supply substrate to the printing press. The substrate, also known as web paper substrate, becomes a decorative layer (301, 302) once the decorative image is inkjet printed on it. In this preferred embodiment, this decorative layer is impregnated by a resin impregnation machine. The method of resin impregnation, using a type of resin impregnation machine or a type of resin, can vary depending on the type of decorative panel; for example, using less resin during resin impregnation, completely impregnating the decorative layer, etc.

[0058] Before supplying one or more sheets to the resin impregnation machine, the first decorative layer and / or the second decorative layer (301, 302) can be cut into one or more sheets, referred to as the roll-to-sheet method, or more preferably, they can be rolled up again as output rolls before being supplied to the hot press (where they are unrolled), referred to as the roll-to-roll method. Figure 3 One or more sheets or output rolls can be supplied to the first resin impregnation machine and the second resin impregnation machine, respectively. Most preferably, the first decorative layer and / or the second decorative layer can also be supplied directly from the web inkjet printing system to the first resin impregnation machine and the second resin impregnation machine, respectively, regardless of whether they are first cut into sheets.

[0059] The location of the first resin impregnation machine / second resin impregnation machine may differ from or be remotely connected to the following: a web-based inkjet printing system and / or a second resin impregnation machine / first resin impregnation machine. Remote location means that the first resin impregnation machine is located at another address, such as a street further away, another city, or even another country.

[0060] Decorative panels (331, 332) Decorative panels are preferably selected from kitchen panels, floor panels, furniture panels, ceiling panels, and wall panels.

[0061] Decorative panels (331, 332) are constructed together for large flat surfaces (see http: / / www.unilin.com / en / flooring), such as floors or walls, or for cabinets or side panels that comprise one or more large flat surfaces (see http: / / www.unilin.com / en / panels).

[0062] The manufacturing method of the present invention preferably includes a paper substrate in the first decorative layer and the second decorative layer (301, 302), the paper substrate having one or more ink receiving layers on its surface printed by water-based coloring inkjet ink. The outermost ink receiving layer from the one or more ink receiving layers is free of inorganic pigments or contains a smaller amount of inorganic pigments than the ink receiving layer between the paper substrate and the outermost ink receiving layer. The outermost ink receiving layer is the layer that first receives droplets from the inkjet printhead. Prior to hot pressing, the paper substrate is preferably impregnated with a thermosetting resin.

[0063] The decorative panel can also be a decorative vinyl sheet. A method for manufacturing such a decorative vinyl sheet is further disclosed. The manufacturing method of the present invention preferably includes a thermoplastic substrate inkjet-printed with UV-curable coloring inkjet ink in the first and second decorative layers (301, 302).

[0064] a) Manufacturing decorative panels (331, 332) The method of manufacturing the decorative panels (331, 332) of the present invention involves hot-pressing a first decorative layer (301) onto the top of a core layer (321, 322) (preferably a wood-based layer). Prior to the inkjet printing step, the roll paper substrate for the first decorative layer and / or the second decorative layer (302) can be impregnated with a thermosetting resin, or the substrate can be inkjet-printed prior to the hot-pressing steps via a first hot press and a second hot press (401 and 402), thereby impregnating the first and second decorative layers (301, 302) with a thermosetting resin.

[0065] Various industry standards are available specifically for high-pressure decorative panels (331, 332), such as European standard EN438 (all parts) and international standard ISO 4586-1.

[0066] The thermosetting resin is preferably selected from melamine-formaldehyde resin, urea-formaldehyde resin and phenol-formaldehyde resin; and the inkjet receiving layer preferably contains inorganic pigment P and polymer binder B; and wherein pigment P is selected from hydrated alumina, alumina, aluminum hydroxide, aluminum silicate and silicon dioxide.

[0067] In a preferred embodiment of the method for manufacturing decorative panels (331, 332), the decorative panels include tenons and grooves enabling a minimally glued mechanical joint between the decorative panels (331, 332). Such tenons and grooves are applied to the decorative panels primarily by drilling methods (e.g., by milling cutters or helical wicks). The decorative panels can be cut into smaller decorative panels (850, 341). Significant variations in panel format exist prior to cutting into smaller decorative panels. For example, Arpa Industriale... TM The following sizes are manufactured in its production: 2440×1220, 3050×1300, 4200×1300, 4200×1600, 4300×1850, defined in mm, with thicknesses varying between 0.6 and 30 mm. For each size, an additional hot press may be required.

[0068] A circular saw can be used to cut smaller decorative panels, such as decorative laminates. Recommended specifications for a circular saw include a tooth pitch of 10-15 mm, a cutting speed of 3000-4000 rpm, and a feed speed of 15-30 m / min. The blades should not be too thin. If their thickness is less than 2 mm, they lose rigidity and then vibrate, making the cut less precise.

[0069] The preferred manufacturing method is part of the DPL method, wherein the decorative layer is contained in a stack to be pressed together with the core layer (321, 322) and the protective layer, and preferably also with the balancing layer. It is not excluded that the method of the present invention may be part of the CPL (Compact Laminate) or HPL (High Pressure Laminate) method, wherein the decorative layer is hot-pressed with at least a plurality of resin-impregnated core paper layers, such as so-called kraft paper, to form the substrate beneath the decorative layer, and in the case of HPL, wherein the resulting pressed and cured laminate layer or laminate board is glued to other substrates, such as particleboard, MDF, or HDF board.

[0070] In a preferred embodiment, a protective layer containing a thermosetting resin is applied to the first decorative layer and / or the second decorative layer (301, 302), respectively, wherein the thermosetting resin may be a colored thermosetting resin to reduce the amount of inkjet ink to be printed. The preferred ink kit is a colored water-based inkjet ink kit, rather than a colored radical UV-curable ink kit, because the colored radical UV-curable ink kit is not very compatible with the use of thermosetting resins in this method.

[0071] The method of manufacturing the decorative panel preferably includes providing an embossed design in at least a protective layer, more preferably by a short-cycle embossing machine, and most preferably by a digital embossing machine. Embossing preferably occurs simultaneously with the core layer (321, 322), the first decorative layer (301), and the protective layer, and preferably one or more balancing layers, being hot-pressed together. The embossing in the protective layer preferably corresponds to a decorative image depicted from the first decorative layer (301). The same applies to the second decorative layer (302) of the invention.

[0072] The decorative panel may have tongue and groove joints and preferably includes at least a core layer (321, 322), a first decorative layer (301) containing a decorative image, and a protective layer. To protect the color image of the first decorative layer (301) from wear, a protective layer is applied on top of the decorative layer. A balancing layer may also be applied to opposite sides of the core layers (321, 322) to limit or prevent possible bending of the decorative panel. Assembling the balancing layer, core layer (321, 322), decorative layer, and protective layer into the decorative panel is preferably carried out in the same hot-pressing process using the preferred DPL method (Direct Pressure Laminate). The same applies to the second decorative layer (302) of the invention.

[0073] The types of tenons and grooves can also be incorporated into the printing process.

[0074] In a preferred embodiment of the decorative panel, the tongue and groove contours are ground into the sides of the individual decorative panels, allowing them to slide into each other. In the case of floor panels, the tongue and groove engagement ensures a robust floor structure and protects the floor from moisture penetration.

[0075] The upper surface of the decorative panel is preferably provided with an embossing that matches the decorative image, such as to highlight wood grain, cracks, and nuts in the decorative image. Embossing techniques for achieving such embossing are known, for example, as disclosed in EP 1290290 A (FLOORING IND), US 2006144004 (UNILIN), EP 1711353 A (FLOORING IND) and US2010192793 (FLOORING IND).

[0076] b) Core layer of decorative panel The core layer (321, 322) is preferably made of a wood-based material, such as particleboard, MDF or HDF (medium-density fiberboard or high-density fiberboard), oriented strand board (OSB), etc. It can also be made of composite materials or water-cured boards (e.g., cement board). In a particularly preferred embodiment, the core layer (321, 322) is MDF or HDF board. Wood chip laminate, plywood, or even solid wood can also be used as the core layer (321, 322). Solid wood is not preferred as the core layer (321, 322) because it may shrink and cause ripples on the surface of the decorative panel, especially for certain decorative panel requirements, for which wood chip laminate and plywood are most preferred, such as stability, flatness, rigidity, mechanical properties, thickness uniformity, water and moisture resistance, and fire resistance.

[0077] The core layers (321, 322) may also be assembled from at least a plurality of paper sheets or other carrier sheets impregnated with a thermosetting resin, as disclosed in WO 2013 / 050910 (UNILIN). Preferred paper sheets include so-called kraft paper obtained by a chemical pulping method (also known as the kraft paper method, for example, as described in US 4952277 (BET PAPERCHEM)). The core layers may also be impregnated with resin.

[0078] In another preferred embodiment, the core layer (321, 322) is a board material substantially composed of wood fibers bonded together by a condensation adhesive, wherein the condensation adhesive forms 5-20% by weight of the board material, and at least 40% by weight of the wood fibers are derived from recycled wood. Suitable examples are disclosed in EP 2374588 A (UNILIN).

[0079] Instead of a wood-based core layer, synthetic core layers, such as those disclosed in US 2013062006 (FLOORINGIND), may also be used. In a preferred embodiment, the core layer (321, 322) comprises a foamed synthetic material, such as foamed polyethylene or foamed polyvinyl chloride.

[0080] Other preferred core layers (321, 322) and their manufacture are disclosed in US 2011311806 (UNILIN) and US6773799 (DECORATIVE SURFACES).

[0081] The thickness of the core layer (321, 322) is preferably between 2 and 12 mm, more preferably between 5 and 10 mm.

[0082] c) Paper substrate for decorative panels The first decorative layer and / or the second decorative layer, and preferably a protective layer and / or optional balancing layer, comprise paper as the substrate. In this invention, the substrate is a roll paper substrate supplied to the rollers of a roll-to-roll inkjet printing system. The substrate included in the first decorative layer (301) of this invention may differ from the substrate included in the second decorative layer (302) of this invention. The possibility of supplying different substrates in a roll-to-roll inkjet printing system makes this invention user-friendly, versatile, easy to manage, and usable on production lines with several hot presses of different configurations.

[0083] Paper with a preferred weight of less than 150 g / m 2 This is because heavier paper sheets are difficult to impregnate with thermosetting resin over their entire thickness. Preferably, the paper weight (i.e., without considering the resin applied thereto) is 50-100 g / m². 2 Between, and possibly as high as 130 g / m 2 The weight of the paper cannot be too high, otherwise the amount of resin required to fully impregnate the paper will be too high, and it will become very impractical to reliably further process the printed paper during the pressing operation.

[0084] According to Gurley's method (DIN 53120), the preferred porosity of the paper is between 8 and 20 seconds. Such porosity allows for even greater than 150 g / m³. 2 Thick sheets are easier to impregnate with a relatively large amount of resin.

[0085] Suitable paper has high porosity, and its manufacture is also disclosed in US 6709764 (ARJO WIGGINS).

[0086] The paper used for the first and / or second decorative layers is preferably white paper and may include one or more whitening agents, such as titanium dioxide, calcium carbonate, etc. The presence of whitening agents helps to mask color differences on the core layers (321, 322), which can cause undesirable color effects on the decorative image.

[0087] Alternatively, the paper for the decorative layer is preferably body-colored paper, which includes one or more colored dyes and / or colored pigments. Besides masking color differences on the core layers (321, 322), using colored paper also reduces the amount of inkjet ink required to depict the decorative image. For example, light brown or gray paper can be used to depict the decorative image to reduce the amount of inkjet ink needed.

[0088] In a preferred embodiment, unbleached kraft paper is used as the brownish paper in the decorative layer. The low lignin content of the kraft paper results in high tensile strength. A preferred type of kraft paper is 40-135 g / m³ with high porosity. 2 It is an absorbent kraft paper, and is made of clean, low-κ hardwood kraft paper with good uniformity.

[0089] If the protective layer includes paper, then paper that becomes transparent or translucent after resin impregnation is used, so that the decorative images in the decorative layer can be seen.

[0090] The paper described above can also be used for the balancing layer.

[0091] d) Ink receiving layer of decorative panel One or more ink acceptor layers may be present on the paper substrate of the decorative layer to enhance image quality.

[0092] One or more ink acceptor layers may be pure polymer-based ink acceptor layers, but preferably contain inorganic pigments and polymer binders. The inorganic pigments may be a single type of inorganic pigment or a variety of different inorganic pigments. The polymer binders may be a single type of polymer binder or a variety of different polymer binders.

[0093] In a preferred embodiment, the total dry weight of one or more ink receiving layers is 2.0 g / m³. 2 Up to 10.0 g / m 2 More preferably, 3.0-6.0 g / m 2 between.

[0094] In a particularly preferred embodiment, one or more ink receiving layers comprise a polymer binder, preferably a water-soluble polymer binder (>1 g / L water at 25°C), having hydroxyl groups as hydrophilic structural units, such as polyvinyl alcohol.

[0095] Inorganic pigments are preferably selected from hydrated alumina, alumina, aluminum hydroxide, aluminum silicate, and silicon dioxide.

[0096] Particularly preferred inorganic pigments are silica particles, colloidal silica, alumina particles, and pseudoboehmite, because they form a better porous structure. When used herein, the particles can be primary particles used directly as is, or they can form secondary particles. Preferably, the average primary particle size is 2 µm or less, and more preferably 200 nm or less.

[0097] Another preferred type of inorganic pigment is silica, which can be used either in its anionic form or as is after cationic modification. Silica can be selected from different types, such as crystalline silica, amorphous silica, precipitated silica, pyrolytic silica, silica gel, spherical and non-spherical silica.

[0098] In a further preferred embodiment, the ink accepting layer may be further crosslinked. Any suitable crosslinking agent known in the art can be used. Boric acid is particularly preferred as a crosslinking agent for the ink accepting layer according to the invention.

[0099] One or more ink acceptor layers may include other additives, such as colorants, surfactants, biocides, antistatic agents, abrasion-resistant hard particles, elastomers, UV absorbers, organic solvents, plasticizers, light stabilizers, pH adjusters, antistatic agents, whitening agents, matting agents, etc.

[0100] One or more ink acceptor layers may consist of a single layer, or even two, three, or more layers with different compositions. One or more ink acceptor layers can be applied to the support side of the substrate using any conventional coating technique, such as dip coating, blade coating, extrusion coating, spin coating, hopper coating, and curtain coating. Alternatively, one or more ink acceptor layers can also be applied using printing techniques, such as flexographic printing, screen printing, and inkjet printing techniques, such as valve jet printheads.

[0101] The thickness of the ink receiving layer was found to affect the quality of the decorative image contained in the decorative panel; the temperature and pressure of the hot pressing also affect the quality of the image. Therefore, for an ink receiving layer of a certain thickness, a different temperature / pressure setting is required. Switching between these settings can take too long, so another heating method can be used, and this invention provides a solution.

[0102] e) Thermosetting resin for decorative panels The thermosetting resin used in this invention is preferably selected from melamine-formaldehyde resin, urea-formaldehyde resin and phenol-formaldehyde resin.

[0103] The preferred thermosetting resin is melamine-formaldehyde resin, which is commonly referred to in the art simply as "melamine (based) resin".

[0104] The preferred formaldehyde-to-melamine ratio in melamine-formaldehyde resin is 1.4-2. Such melamine-based resins are those that undergo condensation polymerization when exposed to heat during pressing. The condensation reaction produces water as a byproduct. This invention is particularly concerned with these types of thermosetting resins, i.e., those that produce water as a byproduct. Prior to pressing, the water produced, and any water residue in the thermosetting resin, must largely leave the hardened resin layer before being trapped, resulting in a loss of transparency in the hardened layer. Available ink layers can hinder the diffusion of vapor foam to the surface, leading to adhesion problems.

[0105] The paper preferably contains 40-250% thermosetting resin by weight relative to the dry weight of the resin. Experiments have shown that this range of resin application provides adequate impregnation of the paper, which largely prevents separation and significantly stabilizes the paper's dimensions.

[0106] The paper preferably contains such a quantity of thermosetting resin that at least the paper core meets the resin requirement. This level of satisfaction can be achieved when the amount of resin provided is at least 1.5 times or at least 2 times the weight of the paper.

[0107] Preferably, the resin provided on the paper is in what is called stage B. Stage B exists when the thermosetting resin is not fully cross-linked.

[0108] Preferably, the relative humidity of the resin provided on the paper is less than 15%, and more preferably 10% by weight or less.

[0109] The preferred step of providing the thermosetting resin to the paper involves applying a mixture of water and resin onto the paper. Applying the mixture may involve immersing the paper in a mixture bath and / or spraying or jetting the mixture. Preferably, the resin is provided in a metered manner, for example, by using one or more squeeze rollers and / or scrapers to set the amount of resin added to the paper layer.

[0110] The method of resin impregnating paper substrates with resin is well known in the art, as exemplified in WO 2012 / 126816 (VITS).

[0111] f) Decorative layer of decorative panel The decorative layer comprises a substrate, such as paper, and a decorative image printed using inkjet technology. In the assembled decorative panel, the inkjet-printed decorative image is located on the side of the paper opposite to the side facing the core layer (321, 322). The paper may be impregnated with a thermosetting resin after the decorative image is printed, or the paper may be impregnated with a thermosetting resin before the decorative image is printed.

[0112] Decorative panels, such as flooring panels, preferably have a decorative layer on one side of the core layer (321, 322) and a balancing layer on the other side of the core layer (321, 322). However, the decorative layer can be applied to both sides of the core layer (321, 322). The latter is particularly desirable in the case of laminated material panels used for furniture. In such cases, a protective layer is also preferably applied to both decorative layers present on both sides of the core layer (321, 322).

[0113] A printed decorative image is obtained by spraying and drying one or more water-based inkjet inks from a water-based inkjet ink kit onto one or more ink receiving layers.

[0114] g) Protective layer of decorative panel Apply a protective layer to the depicted wood pattern, for example by a covering layer (i.e., a carrier for the resin) or a liquid coating, preferably while the decorative layer is loosely or already attached or adhered to it on the core layer (321, 322).

[0115] In a preferred embodiment, the carrier of the cover layer is paper impregnated with a thermosetting resin that becomes transparent or translucent after hot pressing in the DPL method. A preferred method for manufacturing such a cover layer is described in US 2009208646 (DEKOR-KUNSTSTOFFE).

[0116] The liquid coating preferably comprises a thermosetting resin, but may also be another type of liquid, such as a UV-curable varnish or an EB-curable varnish. In a particularly preferred embodiment, the liquid coating comprises melamine resin and hard particles, such as corundum.

[0117] The protective layer is preferably the outermost layer, but in another embodiment, a thermoplastic or elastomer surface layer may be applied to the protective layer, preferably made of a pure thermoplastic or elastomer material. In the latter case, a layer based on a thermoplastic or elastomer material is also preferably applied to the other side of the core layer (321, 322).

[0118] The step of providing a protective layer of thermosetting resin on the printed image preferably involves a pressing process. Preferably, a temperature above 150°C, more preferably between 180-220°C, and a pressure greater than 20 bar, more preferably between 35-40 bar, are applied during the pressing process.

[0119] h) Balancing layer of decorative panel The primary purpose of one or more balancing layers is to compensate for tension by layers on opposite sides of the core layers (321, 322), thereby obtaining a substantially flat decorative panel. Such balancing layers are preferably thermosetting resin layers, which may include one or more carrier layers, such as paper sheets.

[0120] As explained above regarding furniture panels, one or more balancing layers can be decorative layers, optionally supplemented by protective layers.

[0121] Instead of one or more transparent balancing layers, an opaque balancing layer can also be used, which gives the decorative panel a more attractive look by concealing surface irregularities. Additionally, it can contain text or graphic information, such as company logos or other text messages.

[0122] i) Post-forming Manufacturing decorative panels can include a post-forming step on a curved core layer to produce decorative panels without sharp corners. Sharp corners can be areas where water or dust can accumulate; these are prevented during hot pressing on the curved core layer. Such decorative panels are sometimes called thermoformed post-formed decorative panels. Therefore, the temperature of the hot press is controlled very precisely to prevent cracking, separation, delamination, or blistering from occurring on or within the decorative panel.

[0123] If the metadata of the print job / decorative image contains information for manufacturing such thermoformed decorative panels, the correct hot press and / or the printing area for the correct hot press can be assigned from that metadata.

[0124] Monitoring and controlling temperature is crucial in the manufacturing process of such decorative panels. Specifically, the temperature depends on the radius of curvature, the thickness of the decorative layer, the pressure applied to the decorative layer by the hot press, the coverage of the decorative image on the layer, and the humidity of the decorative layer. Temperature monitoring can be achieved, for example, using an infrared detector.

[0125] The hot pressing step can be performed using infrared equipment, a heating plate, a heating rod, or a heated metal tube, and is similar to the hot pressing step in the embodiments and preferred embodiments of the present invention.

[0126] The preferred decorative layer is first formed and then bonded to the core layer or other layers by hot pressing.

[0127] Decorative vinyl board The manufacture of decorative vinyl panels is an example of the decorative panels of the present invention, wherein images are drawn in detail by inkjet technology as disclosed in WO2016188745 (AGFA GRAPHICS).

[0128] Water resistance is therefore important, for example, in personalized decorative flooring in bathrooms. The paper substrate from the aforementioned decorative panel manufacturing methods is preferably replaced by a thermoplastic substrate based on materials selected from: polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), and thermoplastic polyurethane (TPU), and combinations thereof. PVC is most preferred as the thermoplastic substrate. Conventional decorative laminate panels made of PVC are known in the industry as LVT, an abbreviation for luxury vinyl board. In a preferred embodiment, one or more free-radical UV-curable inkjet inks are used instead of solvent-based inkjet inks for inkjet printing decorative images, as this not only offers economic and environmental advantages but also improves image quality due to UV curing freezing the inkjet image.

[0129] Decorative vinyl panels are assembled together for use on large, flat surfaces such as floors or walls.

[0130] The advantage of decorative vinyl panels is that they can be used in damp environments such as bathrooms, floors, and walls.

[0131] a) Manufacturing decorative vinyl boards In a preferred embodiment, the method of manufacturing the decorative panel of the present invention further includes the step of hot-pressing a first decorative layer and / or a second decorative layer (301, 302) and other substrates, wherein the other substrates and decorative layers are thermoplastic foils. The preferred ink kit is a kit of free-radical UV-curable inks, rather than a kit of colored water-based inkjet inks, because the adhesion of such inkjet inks to the thermoplastic foil cannot be guaranteed and may lead to delamination.

[0132] The preferred method for manufacturing decorative vinyl sheets includes the following steps in sequence: a) By spraying one or more coloring free radical UV-curable inkjet inks onto a first thermoplastic foil as a substrate and UV curing it, a decorative image is inkjet printed on the first thermoplastic foil to form a first decorative layer and / or a second decorative layer (302). b) Applying a second thermoplastic foil to the depicted decorative image, the second thermoplastic foil carrying a layer containing a vinyl chloride-vinyl acetate-vinyl alcohol copolymer, wherein the decorative layer faces the inkjet-printed decorative image on the first thermoplastic foil; and c) Hot-pressing a first thermoplastic foil and a second thermoplastic foil into a decorative panel; wherein at least one of the first thermoplastic foil and the second thermoplastic foil is a transparent thermoplastic foil; and wherein one or more coloring free radical UV-curable inkjet inks contain a polymerizable composition having: 30-90% by weight of one or more compounds having one olefinic unsaturated polymerizable group; 10-70% by weight of one or more compounds having two olefinic unsaturated polymerizable groups; and 0-10% by weight of one or more compounds having three or more olefinic unsaturated polymerizable groups, wherein all weight percentages are based on the total weight of the polymerizable composition.

[0133] The method described above includes an additional step d): cutting the decorative panel into one or more decorative vinyl sheets. The method of the present invention can also be used to manufacture wide decorative surfaces (e.g., vinyl rollers), but is preferred for manufacturing decorative panels because the latter does not require experienced workers to apply them and remove all furniture from the room.

[0134] The foils are thermoplastic, allowing them to be fused together during hot pressing. The hot pressing is preferably performed by preheating the first and second thermoplastic foils to a temperature preferably above 130°C, more preferably between 140-170°C, and then preferably using a cold press to fuse them into a decorative panel. Alternatively, the press containing the first and second thermoplastic foils can be heated to a temperature above 130°C, followed by cooling, to fuse the first and second thermoplastic foils into a decorative panel. The pressure used in both methods is preferably greater than 10 bar, more preferably between 15-40 bar.

[0135] Thermoplastic foil is preferably selected from polyvinyl chloride (PVC), polyolefins (such as polyethylene (PE) and polypropylene (PP)), polyamide (PA), polyurethane (PU), polystyrene (PS), acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyetheretherketone (PEEK), or mixtures or copolymers thereof.

[0136] In a preferred embodiment, the first and second thermoplastic foils are polyvinyl chloride (PVC) foils. The PVC foils are preferably rigid types containing less than 10% by weight of plasticizer, more preferably containing 0-5% by weight of plasticizer. The plasticizer may be a phthalate plasticizer, but for health reasons, a non-phthalate plasticizer is preferred.

[0137] Preferred non-phthalate plasticizers include diisononyl cyclohexane-1,2-dicarboxylate (DINCH), dipropylene glycol dibenzoate (DGD), diethylene glycol dibenzoate (DEGD), triethylene glycol dibenzoate (TEGD), acetylated monoglycerides of fully hydrogenated castor oil (COMGHA), isosorbide dimethyl terephthalate (DITT), and vegetable oil-based plasticizers such as Ecolibrium from DOW. TM , and their blends.

[0138] In a preferred embodiment, a decorative image is inkjet printed using a kit of coloring UV-curable inkjet inks, the inks being cured by a UV source, preferably one or more UV LEDs. Many light sources exist in UV radiation, including high-pressure or low-pressure mercury lamps, cold cathode tubes, black light, UV LEDs, UV lasers, and flash lamps. Preferred sources are those exhibiting a relatively long wavelength UV contribution with a dominant wavelength of 300-400 nm. In particular, UV-A light sources are preferred because their reduced light scattering leads to more efficient internal curing. One or more such light sources can be included in a web-based inkjet printing system.

[0139] b) First thermoplastic foil for decorative vinyl sheet The first thermoplastic foil includes a thermoplastic foil and a decorative image drawn on it using inkjet technology.

[0140] Preferably, the thickness of the first thermoplastic foil is at least 80 µm. When the inkjet image is drawn on the transparent thermoplastic foil used as a protective outer layer for the decorative panel, its thickness is preferably greater than 100 µm, more preferably 200-700 µm, and most preferably 300-500 µm.

[0141] If the first thermoplastic foil is used as a protective outer layer for a decorative panel, it may include additional finishing layers on its surface as described below with respect to the second thermoplastic foil.

[0142] c) Second thermoplastic foil for decorative vinyl sheets The second thermoplastic foil preferably carries a layer containing a vinyl chloride-vinyl acetate-vinyl alcohol copolymer. Such a layer ensures optimal adhesion to the depicted decorative image while maximizing flexibility through the use of coloring radical-curable UV-curable inkjet inks containing a large number of compounds with a single olefinic unsaturated polymerizable group in the polymerizable composition of the inkjet ink. This layer preferably comprises a vinyl chloride-vinyl acetate-vinyl alcohol copolymer containing more than 80% by weight of vinyl chloride and 1-15% by weight of vinyl alcohol based on the total weight of the copolymer. Another advantage of including vinyl alcohol in a particular vinyl chloride-vinyl acetate copolymer is that the layer becomes non-sticky, and the second thermoplastic foil can be stored as a roll without causing stickiness problems.

[0143] The application of a layer containing a vinyl chloride-vinyl acetate-vinyl alcohol copolymer is preferably performed using a coating technique selected from spraying, dip coating, blade coating, extrusion coating, spin coating, hopper coating, and curtain coating.

[0144] A layer containing a vinyl chloride-vinyl acetate-vinyl alcohol copolymer is applied to have a dry weight preferably of 1-10 g / m³. 2 More preferably 2-7 g / m 2 The optimal value is 3-6 g / m 2 Less than 1 g / m 2 It does not provide good adhesion, and is greater than 10 g / m 2 Then the problems of adhesion and stickiness can be observed again. When using 2-6 g / m³... 2 When dry-coating, very consistent quality is obtained.

[0145] The coating solution for the vinyl chloride-vinyl acetate-vinyl alcohol copolymer is preferably prepared using an organic solvent with a boiling point not exceeding 95°C under normal pressure. The organic solvent used for the vinyl chloride-vinyl acetate-vinyl alcohol copolymer is preferably selected from methyl ethyl ketone or ethyl acetate to minimize the risk of explosion.

[0146] The second thermoplastic foil is preferably used as an outer layer in the decorative panel, thus forming a transparent protective layer for the visible depiction of decorative images. However, an additional finishing layer may be applied to the protective layer.

[0147] In a particularly preferred embodiment, the decorative panel has a polyurethane finishing layer on the protective layer.

[0148] The second thermoplastic foil preferably has a thickness of at least 80 µm. When the second thermoplastic foil is used as a protective outer layer of a decorative panel, its thickness is preferably greater than 100 µm, more preferably 200-700 µm, and most preferably 300-500 µm.

[0149] d) Base layer of decorative vinyl board In a preferred embodiment, the decorative panel includes a base layer. The base layer provides sufficient rigidity to the decorative panel so that the panel will not break when, for example, a long rectangular decorative panel bends under its own weight. For this reason, the base layer is preferably fiber-reinforced.

[0150] In the decorative panel, the base layer is attached to the side of the opaque thermoplastic foil of the first thermoplastic foil and the second thermoplastic foil, or if both the first thermoplastic foil and the second thermoplastic foil are transparent thermoplastic foils, the base layer is attached to the side of the transparent thermoplastic foil.

[0151] In a preferred embodiment, the base layer comprises essentially polyvinyl chloride and reinforcing fibers. More preferably, the base layer comprises essentially polyvinyl chloride and glass fibers.

[0152] The base layer can consist of two foils, preferably polyvinyl chloride foil, with glass fiber strands inserted.

[0153] The base layer may contain minerals. Talc or calcium carbonate (chalk), alumina, and silica are particularly suitable in this study. The base layer may include flame retardants.

[0154] The base layer can also be a so-called wood-plastic composite (WPC), preferably comprising one or more polymers or copolymers selected from polypropylene, polyethylene and polyvinyl chloride.

[0155] ink Decorative images are printed using inkjet printing with one or more inks, preferably inkjet inks with different colors (M types of inks, I...). 1..M This refers to a variety of inkjet inks used in inkjet printing. The inkjet inkjet inkjet inkjet kit can be a standard CMYK inkjet kit, but a CRYK inkjet inkjet kit is preferred, in which magenta (M) ink is replaced by red (R) inkjet ink. The use of red inkjet ink enhances the color gamut of the decorative image. The decorative image primarily has a brown background. Using red (R) inkjet inkjet ink is preferred over magenta inkjet ink to save more ink.

[0156] Inkjet ink kits can be further expanded with additional inks such as brown (BR), magenta (M), red (R), green (GR), blue (BL), and / or orange (OR) to broaden the color gamut. Inkjet ink kits can also be expanded by combining full-density inkjet inks with light-density inkjet inks. Such combinations of dark and light inks and / or black and gray inks improve image quality by reducing grain.

[0157] Inkjet ink kits can be kits of coloring free radical UV-curable inks or kits of coloring water-based inkjet inks.

[0158] a) Coloring free radical UV-curable ink In a preferred embodiment, the M types of inks (I) of the present invention 1..M (This refers to a variety of coloring radical UV-curable inks that can be used in inkjet technology, also known as coloring radical UV-curable inkjet inks.) Decorative images are drawn using one or more coloring radical UV-curable inkjet inks, wherein the ink preferably contains a polymerizable composition having 30-90% by weight of one or more compounds having one olefinic unsaturated polymerizable group; 10-70% by weight of one or more compounds having two olefinic unsaturated polymerizable groups; and... 0-10% by weight of one or more compounds having three or more olefinically unsaturated polymerizable groups, wherein all weight percentages (%) are based on the total weight of the polymerizable composition.

[0159] In a particularly preferred embodiment, the amount of one or more compounds having an olefinic unsaturated polymerizable group is greater than 72% by weight, more preferably greater than 80% by weight, wherein the weight percentage (wt%) is based on the total weight of the polymerizable composition.

[0160] In a preferred embodiment, the polymerizable compound consists of more than 80% by weight, preferably more than 90% by weight, of acrylate and optionally N-vinyl lactam, wherein the weight percentages are based on the total weight of the polymerizable composition. Such inkjet inks exhibit high curing speeds and are particularly suitable for UV LED curing.

[0161] In the most preferred embodiment, the inkjet ink does not contain intentionally added water or organic solvents, but may contain a very small amount of water, typically less than 5% by weight, based on the total weight of the ink. This water is not intentionally added but enters the formulation as a contaminant through other components, such as polar organic solvents. Higher water contents than 5% by weight based on the total weight of the ink generally destabilize the inkjet ink; preferably, the water content is less than 1% by weight based on the total weight of the ink, and most preferably, water is not present at all.

[0162] In a less preferred embodiment, the colorable UV-curable inkjet ink contains 20-60% by weight of organic solvent, based on the total weight of the inkjet ink. In such a case, an additional drying device for solvent evaporation becomes necessary in addition to the UV curing apparatus.

[0163] b) Polymerizable compounds The polymerizable compound is preferably present in the colorable UV-curable inkjet ink in an amount of at least 60% by weight, more preferably at least 70% by weight, wherein the weight percentage is based on the total weight of the inkjet ink.

[0164] Any monomer and oligomer capable of free radical polymerization can be used as a polymerizable compound. The viscosity of UV-curable inkjet inks can be adjusted by changing the ratio between the monomer and oligomer. The polymerizable compound can be any monomer and / or oligomer found in PolymerHandbook, Volumes 1+2, 4th Edition, edited by J. BRANDRUP et al., Wiley-Interscience, 1999.

[0165] c) Coloring agents Colored pigments can be black, cyan, magenta, yellow, red, orange, purple, blue, green, brown, or mixtures thereof. Colored pigments can be selected from those disclosed in HERBST, Willy et al., Industrial Organic Pigments, Production, Properties, Applications. 3rd ed. Wiley - VCH, 2004. ISBN 3527305769.

[0166] The preferred pigment for cyan inkjet inks is copper phthalocyanine pigment, more preferably CI Pigment Blue 15:3 or CI Pigment Blue 15:4.

[0167] Particularly preferred pigments for use in red or magenta inkjet inks are CI Pigment Violet 19, CI Pigment Red 254, CI Pigment Red 176, CI Pigment Red 202 and CI Pigment Red 122, and their mixtures.

[0168] Particularly preferred pigments for use in yellow inkjet inks are CI Pigment Yellow 150, CI Pigment Yellow 155, CI Pigment Yellow 120 and CI Pigment Yellow 180, and their mixtures.

[0169] For black inks, suitable pigment materials include carbon black, such as Regal from Cabot Co. TM 400R, Mogul TM L, Elftex TM 320, or CI Pigment Black 7 and CI Pigment Black 11.

[0170] Based on the total weight of the colored inkjet ink, the amount of pigment in the inkjet ink is preferably 0.1-20% by weight, more preferably 1-10% by weight, and most preferably 2-6% by weight. A pigment concentration of at least 2% by weight is preferred to reduce the amount of inkjet ink required to produce the decorative image, while a pigment concentration of more than 5% by weight reduces the color gamut of the decorative image printed using a printhead with a nozzle diameter of 20-50 µm.

[0171] d) Polymer dispersants Colored inkjet inks preferably contain a dispersant, and more preferably a polymeric dispersant for dispersing pigments.

[0172] Typical polymer dispersants are copolymers of two monomers, but may contain three, four, five or even more monomers. The performance of a polymer dispersant depends on both the properties of the monomers and their distribution in the polymer. Suitable polymer dispersants are listed in the "Dispersants" section of EP 1911814 A (AGFA GRAPHICS), more specifically

[0064] to

[0070] and

[0074] to

[0077] .

[0173] The polymer dispersant preferably has a number-average molecular weight (Mn) of 500-30000, more preferably 1500-10000. The polymer dispersant preferably has a weight-average molecular weight (Mw) of less than 100,000, more preferably less than 50,000, and most preferably less than 30,000. The polymer dispersant preferably has a polydispersity (PD) of less than 2, more preferably less than 1.75, and most preferably less than 1.5. Based on the weight of the pigment, the amount of polymer dispersant is preferably 2-600% by weight, more preferably 5-200% by weight, and most preferably 50-90% by weight.

[0174] e) Photoinitiation system A photoinitiation system is used to initiate the polymerization of polymerizable compositions in inkjet inks. A photoinitiation system includes one or more photoinitiators and optionally one or more co-initiators.

[0175] Photoinitiators are free radical initiators. Free radical photoinitiators are compounds that polymerize monomers and oligomers by forming free radicals when exposed to photochemical radiation.

[0176] To further enhance photosensitivity, UV-curable inkjet inks may additionally contain a co-initiator. A preferred co-initiator is an aminobenzoate.

[0177] f) Polymerization inhibitors UV-curable inkjet inks may contain polymerization inhibitors. Suitable polymerization inhibitors include phenolic antioxidants, hindered amine light stabilizers, phosphorescent antioxidants, hydroquinone monomethyl ether (commonly used for (meth)acrylate monomers), and may also include hydroquinone, tert-butylcatechol, and pyrogallol.

[0178] Since adding excessive amounts of these polymerization inhibitors will reduce the ink's sensitivity to curing, it is preferable to determine the amount that can prevent polymerization before blending. Based on the total weight of the inkjet ink, the amount of polymerization inhibitor is preferably less than 2% by weight.

[0179] g) Surfactants Surfactants are used in inkjet inks to reduce the surface tension of the ink, for example, to reduce the contact angle on thermoplastic foil, i.e., to improve the wetting of the foil by the ink. On the other hand, inkjet inks must meet stringent performance standards for high accuracy, reliability, and full jetting performance over extended periods. To achieve both ink wetting of the substrate and high jetting performance, one or more surfactants are typically added to reduce the surface tension of the ink. However, in the case of UV-curable inkjet inks, the surface tension of the inkjet ink is determined not only by the amount and type of surfactant, but also by the polymerizable compounds, polymer dispersants, and other additives in the ink composition.

[0180] One or more surfactants may be anionic, cationic, nonionic or amphoteric, and are typically added in a total amount of less than 20% by weight based on the total weight of the inkjet ink, and particularly less than 10% by weight based on the total weight of the inkjet ink.

[0181] Silicone surfactants are generally preferred for curable inkjet inks, especially reactive silicone surfactants, which can polymerize with polymerizable compounds during the curing step.

[0182] h) Preparation of UV-curable inks with coloring free radicals The preparation of colorable UV-curable inkjet inks is well known to those skilled in the art. Preferred preparation methods are disclosed in paragraphs

[0076] to

[0085] of WO 2011 / 069943 (AGFA).

[0183] i) Coloring Water-Based Inkjet Ink Kit The preferred embodiment of the coloring water-based inkjet ink kit according to the present invention comprises: a) Cyan water-based inkjet ink containing copper phthalocyanine pigment, preferably β-copper phthalocyanine pigment; b) Red water-based inkjet ink containing red pigments selected from CI Pigment Red 254, CI Pigment Red 122, CI Pigment Red 176 and their mixtures. c) Yellow water-based inkjet ink containing pigment CI Pigment Yellow 150 or a mixture thereof; and d) Black water-based inkjet ink containing carbon black pigment; wherein the water-based inkjet ink contains surfactant.

[0184] In addition to specific color pigments, inkjet inks also contain surfactants, preferably fluorinated surfactants. Surfactants allow for spreading on decorative paper, which also indirectly enhances conditional isochromatic properties. In a preferred embodiment of the coloring water-based inkjet ink kit, the coloring water-based inkjet ink has a static surface tension at 25°C between 19.0 mN.m and 27.0 mN.m for good spreading on decorative paper.

[0185] The color angle H* of red inkjet inks is typically in the range of 15° to 65°. To provide good reproduction of wood color images, the color angle H* of the red inkjet inks in this invention is preferably between 15° and 50°, more preferably between 20° and 40°. In a preferred embodiment of the coloring water-based inkjet ink kit, the red pigment is CI Pigment Red 254 or a mixture thereof. The color angle H* in the CIE Lab color space is calculated by the following formula: tan⁻¹(b* / a*) (°), where a* and b* are chromaticity coordinates in the CIE Lab color space.

[0186] The color angle of yellow inkjet inks is typically in the range of 75° to 110°. To provide good reproduction of wood color images, the color angle H* of the yellow inkjet ink in this invention is preferably between 80° and 105°, more preferably between 85° and 95°. In a preferred embodiment of the coloring water-based inkjet ink kit, the color angle H* of the yellow water-based inkjet ink is greater than 85°, more preferably between 86° and 98°, and most preferably between 87° and 95°.

[0187] The coloring water-based inkjet inks in the ink kit should preferably have a color chroma C* of at least 50.

[0188] Water-based coloring inks may contain biocides and / or at least one pH adjuster, such as NaOH, KOH, NET3, NH3, or HCl. Preferred pH adjusters are triethanolamine, NaOH, and H2SO4.

[0189] j) Preparation of coloring water-based inks One or more water-based inkjet inks can be prepared by precipitating or grinding colored pigments in a dispersion medium in the presence of a polymeric dispersant, or simply by mixing self-dispersible colored pigments into the ink. Mixing equipment may include pressure kneaders, open kneaders, planetary mixers, dissolvers, and Dalton universal mixers. Suitable grinding and dispersing equipment includes ball mills, bead mills, and colloid mills.

[0190] If the inkjet ink contains more than one pigment, the colored ink can be prepared using a separate dispersion for each pigment, or alternatively, several pigments can be mixed and co-milled during dispersion preparation. The dispersion process can be carried out in a continuous, intermittent, or semi-intermittent manner. The milling time can vary widely and depends on the pigment, the selected machinery and residence conditions, the initial and desired final particle size, etc. In this invention, pigment dispersions with an average particle size of less than 100 nm can be prepared.

[0191] After grinding, conventional separation techniques, such as filtration or sieving, are used to separate the grinding media from the ground particulate products (in the form of a dry or liquid dispersion).

[0192] k) Polymer latex adhesives One or more water-based inkjet inks may contain a polymer latex binder, preferably a polyurethane-based latex. It has been observed that polyurethane-based latex causes less damage to adhesion in floor laminates than acrylic latex binders.

[0193] There are no particular restrictions on polymer latex binders, as long as they have stable dispersibility in the ink composition. There are also no restrictions on the backbone of water-insoluble polymers.

[0194] In a preferred embodiment, the polymer latex is a polyurethane latex, more preferably a self-dispersing polyurethane latex. Due to its compatibility with thermosetting resins, when used in the manufacture of decorative panels (331, 332), the polymer latex binder in one or more water-based inkjet inks is preferably a polyurethane-based latex binder.

[0195] The latex binder polymer particles preferably have a glass transition temperature (Tg) of 30°C or higher. The minimum film-forming temperature (MFT) of the polymer latex is preferably from -25°C to 150°C, more preferably from 35°C to 130°C.

[0196] l) Injection viscosity and injection temperature The jet viscosity is determined by measuring the liquid viscosity at the jetting temperature. Jetting viscosity can be measured using various types of viscometers, such as the Brookfield DV-II+ viscometer at the jetting temperature and 12 rpm using a CPE 40 spindle (equivalent to 90 s). -1 (shear rate) or using a HAAKE Rotovisco 1 rheometer with a C60 / 1 Ti sensor at 1000 s -1 Determined at shear rate.

[0197] In a preferred embodiment, the spray viscosity is 10 mPa·s-200 mPa·s, more preferably 25 mPa·s-100 mPa·s, and most preferably 30 mPa·s-70 mPa·s.

[0198] The spray temperature can be measured using various types of thermometers. The spray temperature can be measured at the outlet of the nozzle in the printhead during spraying, or it can be determined by measuring the temperature of the liquid in the liquid channel or nozzle as it passes through the nozzle. In a preferred embodiment, the spray temperature is from 10°C to 100°C, more preferably from 20°C to 60°C, and most preferably from 30°C to 50°C.

[0199] Inkjet printhead unit (500) The roll-to-roll inkjet printing system includes an inkjet printhead unit (500) for printing decorative images using an ink cartridge.

[0200] An inkjet printhead unit (500) is a unit comprising multiple inkjet printheads. A printhead is a device for jetting liquid onto a substrate through nozzles. Nozzles may be contained in a nozzle plate attached to the printhead. Multiple nozzles in the printhead form one or more nozzle rows. The inkjet printhead unit (500) of this invention is attached to a roll-to-roll inkjet printing system to mark decorative images on a substrate using inkjet technology. The roll-to-roll inkjet printing system is preferably capable of marking substrates with widths between 1 meter and 5 meters, and if the substrate is not roll paper but sheet paper, the roll-to-roll inkjet printing system is preferably capable of marking substrates with heights between 1 meter and 10 meters. More information on inkjet technology, including the integration of the printhead into an inkjet printhead unit (500) and a web-based inkjet printing system using inkjet technology, is disclosed in STEPHEN F. POND. Inkjet Technology and Product Development Strategies. USA: Torrey Pines Research, 2000 and in Handbook of Industrial Inkjet Printing: A Full System Approach, edited by Werner Zapka (published by Wiley-VCH Verlag GmbH & Co., 22 / 11 / 2017, 984 pages).

[0201] The printhead preferably has multiple nozzles and one or more nozzle rows, which may be contained in a nozzle plate. A set of liquid channels contained in the printhead corresponds to the nozzles of the printhead, meaning that in the drawing method, liquid in this set of liquid channels can exit the corresponding nozzle. The liquid is preferably ink, more preferably a coloring radical UV-curable ink or a coloring water-based inkjet ink. The liquid used for jetting is also called a jettable liquid or inkjet ink. A high-viscosity jetting method using UV-curable inkjet ink is called a high-viscosity UV-curable jetting method. A high-viscosity jetting method using water-based inkjet ink is called a high-viscosity water-based jetting method.

[0202] Typically, the jet viscosity of jettable liquids in the prior art ranges from 3 mPa·s to 15 mPa·s. The jet viscosity of inkjet inks used in the aforementioned fields, such as commercial / trade inkjet printing or wide-format inkjet printing, does not exceed 15 mPa·s. The increased inkjet viscosity, due to a wider selection of raw materials, can allow for improved adhesion to several ink acceptors, such as textiles or glass. This formulation range of jettable liquids allows for the inclusion of oligomers and / or polymers and / or pigments, for example, in higher quantities. This results in a wider range of accessible acceptors; reduced odor and migration, and improved curing speed for UV-curable jettable liquids; environmental, health, and safety (EH&S) benefits; physical performance benefits; reduced raw material costs; and / or reduced ink consumption for higher pigment loadings.

[0203] The method of integrating the printhead into the inkjet printhead unit (500) is well known to those skilled in the art, but is also disclosed in STEPHEN F. POND. Inkjet Technology and Product Development Strategies. USA: Torrey Pines Research, 2000.

[0204] In this invention, the decorative image is preferably drawn in multiple printing processes using inkjet technology. This is because drawing the decorative image in a single process using inkjet technology is prone to operational failures in the routine production of decorative panels, such as nozzle malfunctions in the inkjet printhead unit (500), resulting in "empty" lines in the drawn decorative image and causing material waste by cumbersome removal of these defective decorative panels after hot pressing. These roll-to-roll inkjet printing systems contain a large number of inkjet printheads in the inkjet printhead unit (500) to cover the entire width of the substrate, making them very expensive machines.

[0205] The printhead can be any type of inkjet printhead, such as valve printhead, piezoelectric inkjet printhead, thermal inkjet printhead, continuous inkjet printhead, electrostatic drip-on-demand inkjet printhead, acoustic drip-on-demand inkjet printhead, or page-width inkjet printhead array, also known as page-width inkjet array.

[0206] Preferably, the printhead includes a set of main outlets to perform liquid recirculation through the printhead. Recirculation can occur before the droplet forming apparatus, but more preferably it occurs within the printhead itself, i.e., a so-called through-flow printhead. The continuous flow of liquid in the through-flow printhead removes air bubbles and aggregated particles from the liquid channels of the printhead, thereby avoiding clogged nozzles that would prevent liquid jetting.

[0207] The printhead of the present invention is preferably suitable for spraying liquids with a viscosity of 8 mPa·s to 3000 mPa·s. A preferred printhead is suitable for spraying liquids with a viscosity of 20 mPa·s to 200 mPa·s; and more preferably suitable for spraying liquids with a viscosity of 50 mPa·s to 150 mPa·s.

[0208] piezoelectric inkjet printhead A preferred printhead of the present invention is a piezoelectric inkjet printhead. A piezoelectric inkjet printhead, also known as a piezoelectric inkjet printhead, is based on the movement of a piezoelectric ceramic transducer contained within the printhead when a voltage is applied thereto. The application of voltage alters the shape of the piezoelectric ceramic transducer to create a void in a liquid channel, which is then filled with liquid. When the voltage is removed again, the ceramic expands back to its original shape, ejecting droplets from the liquid channel.

[0209] The droplet forming apparatus of a piezoelectric inkjet printhead controls a set of piezoelectric ceramic transducers to change the shape of the piezoelectric ceramic transducers by applying a voltage. The droplet forming apparatus can be a squeeze-mode actuator, a bending-mode actuator, a push-mode actuator, a shear-mode actuator, or another type of piezoelectric actuator.

[0210] The suitable commercial piezoelectric inkjet printhead is from TOSHIBA TEC. TM TOSHIBA TEC (http: / / www.toshibatec.com / en / products / industrial / inkjet / products / ) TM CK1 and CK1L, and information obtained from XAAR TM (http: / / www.xaar.com / en / products / )XAAR TM 2001.

[0211] The liquid channel in a piezoelectric inkjet printhead is also called a pressure chamber. Between the liquid channel and the main inlet of the piezoelectric inkjet printhead, there is a connecting manifold to store liquid for supply to the liquid channel assembly.

[0212] The piezoelectric inkjet printhead is preferably a flow-through piezoelectric inkjet printhead. In a preferred embodiment, the recirculation of liquid in the flow-through piezoelectric inkjet printhead occurs between a set of liquid channels and the nozzle inlet, wherein the set of liquid channels corresponds to the nozzle.

[0213] In a preferred embodiment of the piezoelectric inkjet printhead, the minimum droplet size of a single ejected droplet is 0.1 pL to 300 pL; in a more preferred embodiment, the minimum droplet size is 1 pL to 30 pL; and in the most preferred embodiment, the minimum droplet size is 1.5 pL to 15 pL. By using grayscale inkjet printhead technology, multiple single droplets can be formed into a larger droplet size.

[0214] In a preferred embodiment, the piezoelectric inkjet printhead has an inherent printing resolution of 25 DPI to 2400 DPI; in a more preferred embodiment, the inherent printing resolution of the piezoelectric inkjet printhead is 50 DPI to 2400 DPI; and in the most preferred embodiment, the inherent printing resolution of the piezoelectric inkjet printhead is 150 DPI to 3600 DPI. DPI is an abbreviation for dots per inch, a well-known measure of spatial printing, specifically the number of individual dots that can be placed in a line within a span of 1 inch (i.e., 2.54 cm).

[0215] In a preferred embodiment of the piezoelectric inkjet printhead, the jet viscosity is from 8 mPa.s to 200 mPa.s, more preferably from 25 mPa.s to 100 mPa.s, and most preferably from 30 mPa.s to 70 mPa.s.

[0216] In a preferred embodiment of the piezoelectric inkjet printhead, the jetting temperature is 10°C to 100°C, more preferably 20°C to 60°C, and most preferably 30°C to 50°C.

[0217] Drying equipment A dryer may be included in a web-based inkjet printing system for removing at least a portion of the inkjet ink used for printing decorative images, such as the water-based medium of water-based inkjet inks. Suitable dryers include devices for circulating hot air, ovens, and devices using air extraction.

[0218] The drying apparatus may include heat conduction devices, such as hot plates or heated drums. A preferred heated drum is an induction heating drum.

[0219] Drying devices may include infrared radiation sources. The maximum emission of effective infrared radiation sources is between 0.8 and 1.5 µm. Such infrared radiation sources are sometimes called NIR radiation sources or NIR dryers.

[0220] NIR radiation can rapidly penetrate deep into the inkjet ink layer and remove water and solvents from the entire layer thickness, while conventional infrared and hot air energy are mainly absorbed on the surface and slowly conducted into the ink layer, which usually results in slower removal of water and solvents.

[0221] In a preferred embodiment, the NIR radiation source is in the form of an NIR LED, which can be easily installed on the shuttle system of multiple inkjet printheads in a multi-pass web inkjet printing system.

[0222] Another preferred drying device uses carbon infrared radiation (CIR).

[0223] UV curing device The UV curing device emits UV radiation, which is absorbed by a photoinitiator or photoinitiation system to polymerize the polymerizable compound in the core. Such a UV curing device is attached to the web inkjet printing system of the present invention if a decorative image is printed on a substrate using a coloring radical UV-curable ink to form a first or second decorative layer (301, 302).

[0224] UV curing apparatus may include high-pressure mercury lamps or low-pressure mercury lamps, but preferably include or consist of UV LEDs.

[0225] The UV curing unit can be arranged in combination with and travel with the inkjet printhead or printhead unit (500) of a web-based inkjet printing system, so that curing radiation is applied very shortly after jetting. Preferably, such a curing unit consists of one or more UV LEDs, because in such an arrangement, it may be difficult to provide other types of curing units small enough to be connected to and travel with the printhead. Alternatively, a static, fixed radiation source, such as a curing UV light source, can be used, connected to the radiation source via a flexible radiation conduction device, such as a fiber optic bundle or an internal reflective flexible tube, or via a mirror arrangement including mirrors on the printhead.

[0226] However, it is not necessary to connect the UV light source to the printhead. The UV radiation source can also be, for example, an elongated radiation source extending laterally across the substrate to be cured. It can be adjacent to the lateral path of the printhead, such that subsequent lines of the decorative image formed by the printhead pass under the radiation source step by step or continuously.

[0227] Any ultraviolet light source can be used as a radiation source, as long as some of the emitted light can be absorbed by a photoinitiator or photoinitiator system, such as high-pressure or low-pressure mercury lamps, cold cathode tubes, black lights, ultraviolet LEDs, ultraviolet lasers, and flash lamps. Preferred light sources are those exhibiting a relatively long wavelength ultraviolet contribution with a dominant wavelength of 300-400 nm. In particular, UV-A light sources are preferred due to their reduced light scattering, leading to more efficient internal curing.

[0228] UV radiation is typically classified as UV-A, UV-B, and UV-C as follows: • UV-A: 400 nm to 320 nm • UV-B: 320 nm to 290 nm • UV-C: 290 nm to 100 nm.

[0229] In a preferred embodiment, the web-based inkjet printing system contains one or more UV LEDs with a wavelength greater than 360 nm, preferably one or more UV LEDs with a wavelength greater than 380 nm, and most preferably a UV LED with a wavelength of about 395 nm.

[0230] Furthermore, two light sources with different wavelengths or illuminances can be used continuously or simultaneously to cure images. For example, a first UV source rich in UV-C can be selected, particularly in the 260 nm to 200 nm range. The second UV source can be rich in UV-A, such as a gallium-doped lamp, or a different lamp with high levels of both UV-A and UV-B. The use of two UV sources has been found to have advantages, such as faster curing speed and higher curing intensity.

[0231] To facilitate curing, web-based inkjet printing systems typically include one or more oxygen-consuming units. These units contain a cover layer of nitrogen or other relatively inert gases (such as CO2) with adjustable position and concentration to reduce the oxygen concentration in the curing environment. Residual oxygen levels are typically kept as low as 200 ppm, but are generally in the range of 200 ppm to 1200 ppm.

[0232] Decoration Workflow System To manage printing operations for manufacturing decorative panels, this could include depicting decorative images by one or more digital drawing devices in a method of manufacturing the decorative panels. This implementation could be performed by a decorative workflow system, which, for example, performs tasks such as determining the decorative image, color conversion of the decorative image, imposing or nesting multiple decorative images on a substrate, and / or digitally cutting the decorative panel containing the depicted decorative image. Workflow systems for depicting images on inkjet printers are known, for example, from Agfa. TM Asanti TM It is a complete, automated marking and display production center, characterized by the integration of Agfa Graphics' award-winning color management solution with the latest version of Adobe PDF Print Engine (APPE), highly specific features (e.g., nesting, proofing support), and fast, automated pre-flighting. A decorative workflow system could be similar, but more extensive for the manufacture of decorative panels.

[0233] The painting process includes the following steps: halftoning the image and transferring the halftoned image to a web-based inkjet printing system, where the transferred halftoned image is marked by the web-based inkjet printing system. Halftoning, sometimes called screening, is the conversion of a continuous-tone bitmap into a halfton (dot pattern). Therefore, the decoration workflow system includes a halftoning processing unit for halftoning and preferably includes a RIP (raster image processor) for rasterizing vector graphics. It also includes a color management system for converting the decorative image into the colors of the inks from the web-based inkjet printing system. The decoration workflow system preferably includes a management information system (MIS) to provide the information needed for the manufacture of decorative panels, to manage them efficiently and effectively, and to analyze and facilitate strategic and operational activities.

[0234] The decorating workflow system operating procedure. Part or all of the decorating workflow system and / or its functional units or blocks can be implemented in one or more loops or circuits (e.g., one or more integrated circuits or as LSIs (Large-Scale Integration)). Each functional unit or block of the decorating workflow system can be fabricated individually as an integrated circuit chip. Alternatively, some or all of the functional units or blocks can be integrated and fabricated as an integrated circuit chip.

[0235] The program operating in the decoration workflow system according to various preferred embodiments of the present invention is a program that controls the processor to implement the functions according to various preferred embodiments of the present invention. Therefore, during processing, information processed by the decoration workflow system is temporarily accumulated in RAM. Subsequently, the information can be stored in various types of circuits in the form of ROM and HDD, and can be read out by circuits within the decoration workflow system when necessary, or included in combination with the decoration workflow system, and modified or written to it. As the recording medium for storing the program, any of the following can be used: semiconductor media (e.g., ROM, non-volatile memory cards, etc.), optical recording media (e.g., DVD, MO, MD, CD, BD, etc.), and magnetic recording media (e.g., magnetic tape, floppy disk, etc.). Furthermore, by executing the loaded program, not only are the functions of the various preferred embodiments of the present invention realized, but also by processing the loaded program in combination with an operating system or other application programs based on program-based instructions, the functions of the preferred embodiments of the present invention can be realized. In the present invention, the decoration image is stored in the memory of the decoration workflow system, similar to the program described above.

[0236] Furthermore, in the case of market distribution, the program can be distributed by storing it on a portable recording medium, or the program can be sent to a server computer connected via a network (such as the Internet). In this case, the storage device of the server computer is also included in the present invention. Additionally, a portion or the entirety of a terminal device, wireless base station, host system, or other device can be implemented as an LSI, which is typically an integrated circuit. Each functional unit or block of the decoration workflow system can be individually chipped, or it can be partially or entirely chipped through integration. When the functional blocks or units are integrated circuits, an integrated circuit controller that controls the integrated circuits is added.

[0237] Finally, it should be noted that descriptions involving "loop" or "circuit" are not in any way limited to hardware implementations only, and as those skilled in the art will know and understand, such descriptions and representations of "loop" or "circuit" include combined hardware and software implementations in which the loop or circuit is operable to perform functions and operations based on machine-readable programs, software, or other instructions of any form that can be used to operate the loop or circuit.

[0238] Printing jobs and corresponding decorative images for the first printing area and the first decorative layer (301), as well as printing jobs and corresponding decorative images for the second printing area and the second decorative layer (302), can be transferred separately from the web-based inkjet printing system to the inkjet printhead unit. However, it is preferable to merge the two printing jobs together first by merging the scan lines of the decorative images before transferring them from the web-based inkjet printing system to the inkjet printhead unit. A scan line is a line or row of the decorative image. Such merging can be performed by a CPU, such as an Intel Xeon w3550 with 4 cores at 3.06 GHz, but a graphics processing unit is more preferred. The advantage of such merging is that the first and second time periods in the present invention are more likely to overlap. The number of copies in the printing job allocated to the first printing area may always be different from the number of copies in the printing job allocated to the second printing area. Moreover, the start times between the two printing jobs may be different.

[0239] The preferred components of a decoration workflow system include: —Color management software to separate decorative images into colors from inkjet ink sets from web-based inkjet printing systems; and / or —Input controller: Enables the decorative image to be read by the inkjet printhead in a web-based inkjet printing system, and also separates the decorative image according to the printing mode (e.g., two passes); and / or —Print Manager: Software that communicates with the entire web-based inkjet printing system and also triggers the image data stream to the inkjet printhead: and / or —Printhead Controller: Controls the inkjet printhead and ensures data is sent to each and all nozzles in a timely manner. Data transmission can be performed at the printing speed, for example, between 1000-20000 Hz in single-pass inkjet printing.

[0240] The decoration workflow system may also have software programs, including a database to manage data records or printing jobs, a customized MRP interface or user interface to connect to machine controls, and a camera system for customized tasks in the manufacturing room.

[0241] Printing producers or brand owners may preferably submit printing jobs for their decorative layers and panels to a submission portal via an online store. In this invention, an online store specifically designed for manufacturing decorative panels is referred to as a decorative storefront.

[0242] Submitting a print job preferably involves providing at least the following information: • A roll-to-roll inkjet printing system on which printing operations are to be performed; • The roll paper substrate on which the printing operation is to be performed; • The quality level of the printing job to be printed; • The number of items to be printed, also known as the number of copies; • A content file describing one or more decorative images to be printed.

[0243] All submitted data together define a print job. Multiple print jobs together define a print job list.

[0244] The submission portal preferably includes a first pre-output pre-check tool. This pre-output pre-check tool checks whether all constraints for printing jobs on a web-based inkjet printing system and the selected web-based substrate are met, and generates warnings or applies fixes in case of inconsistencies.

[0245] For productivity purposes, print producers or brand owners can use product templates with pre-set information, and can also edit multiple variables and data.

[0246] The submission portal has a backend that preferably enables the submission portal operator to perform the following operations: • Obtain an overview of the submitted print jobs in the job list (105); • Manage submitted jobs: preview them, edit them, approve them, change their order, delete them, etc.; • Manage and design product templates; • Perform many administrative tasks, such as creating or deleting online stores, print producer accounts, administrator accounts, etc.

[0247] Portal operators can be print producers or brand owners. These operators can only see jobs created in their associated online decor store. Alternatively, portal operators can be super users with privileges to access all jobs submitted to the portal by various front-end users.

[0248] For printing jobs, you can choose from CIP4. TM The organization's JDF framework. A JDF worksheet is an open, extensible, XML-based specification (www.cip4.org) that includes all production steps to create a printed product. The JDF worksheet in this invention includes production data information about the product specifications, as well as administrative data about the online store and print producers.

[0249] JDDF job sheets provide proprietary XML formatted data. In this invention, this feature can be used to embed a "job XML file." Such a job XML file provides tools that support proprietary instructions for driving proprietary output devices. By embedding the job XML file into the JDDF job sheet, data that would otherwise be unsuitable or not belong to the JDDF job sheet can be stored at the submission portal level.

[0250] JDF job sheets and content files can be optionally packaged in ASCII-encoded container files, such as in MIME files.

[0251] The printing operation preferably also includes the type of hot press, more preferably the type of hot press and / or the specific configuration of the hot press (e.g., temperature, pressure, etc.), so that the correct hot press is correctly assigned to the decorative layer, and the correct printing area of ​​the present invention is supplied with the correct printing operation. Other information in such a printing operation may also be provided, such as how the decorative panel must be cut, what type of mechanical joint must be ground, which other layers must be supplied, etc. All this information is sometimes referred to as metadata. Metadata can also be embedded in the decorative image.

[0252] The more metadata in a printing job, the easier it is to automate the entire manufacturing process of the decorative panel. Metadata can expose several settings: from color management settings and halftone settings to printing mode settings, hot press settings, and cutting settings. Throughout the manufacturing process of the decorative panel, the printing job can be followed, also known as a tracking printing job. Post-processing of the decorative layer containing the inkjet-printed decorative image, such as hot-pressing the decorative layer with other layers into a decorative panel, applying an embossed structure to the decorative panel if not done in the hot-pressing step, cutting the decorative panel into decorative laminates, and grinding mechanical joints, such as tongues and grooves, on the decorative laminates, can be done remotely for economic and ecological reasons, bringing these post-processing steps closer to the consumer and thus minimizing transport distances and emissions from the final product being transported to the consumer. This is therefore an advantage of tracking machinery for such printing jobs.

[0253] Another advantage is that accurate color conversion can be achieved regardless of whether the hot press is allocated through analysis of the printing job. It has been found that when heat-setting to the decorative panel, the type and specific construction of the hot press, such as a particular temperature setting, can affect the color of the decorative layer. The decorative workflow system can provide a color management system that takes into account the allocation of hot presses.

[0254] The type and / or specific construction of the hot press can be determined by analyzing the printing job. For example, the printing job may also contain details of the sender (such as a brand owner or printer), thereby allowing the decoration workflow system to analyze which type of hot press should be used based on the sender's known wishes. This analysis of the hot press type and / or specific construction is then incorporated into the decoration workflow system. Another example is analyzing the content of the decorative image to be printed, thereby allowing the decoration workflow system to determine the type and / or specific construction of the hot press. This analysis of the hot press type and / or specific construction is then incorporated into the decoration workflow system. An example of analysis of the decorative image (such as image analysis) could include the total coverage of the decorative image. Darker decorative images typically require higher pressure, and hot pressing involves decorative layers of such images. Analysis (such as image analysis) can be performed in pre-output inspection tools.

[0255] An overview of image analysis methods that can be performed through the decorative workflow system is published in PRATT, William K. Digital Image Processing: PIKS Scientific Inside. 4th ed. John Wiley, Part 5, “Image Analysis” [pp. 419-678].

[0256] Preferred image analysis methods included in the analysis of decorative image methods include: —Edge detection; and / or —Image segmentation; and / or —Shape analysis; and / or —Texture analysis.

[0257] Other examples of analysis of decorative images / printing jobs: —The size is determined, thereby assigning the correct type of hot press capable of hot pressing such a size.

[0258] —Delivery addresses for one or more decorative panels are determined, and these addresses are subsequently disclosed in the printing job. Based on the delivery addresses, the nearest hot press is assigned to the printing job, thus reducing production time and transport costs. After analyzing the delivery addresses, the identification of the locations for the hot presses is later incorporated into the printing job. Location identification can be determined from a database connected to a decorative workflow system containing the locations of several hot presses.

[0259] The structural settings determined from the analysis or added in the printing operation can be marked on the decorative layer by text or, more preferably, by an identification code (such as a barcode or QR code). An identification code reader connected to the hot press can read the identification code, and the controller can configure the hot press according to the content of the identification code. The identification code is preferably applied via the web-based inkjet printing system of the present invention, and more preferably via the inkjet printhead included in the inkjet printhead unit (500), and thus applied together with one of the inks in the ink kit of the web-based inkjet printing system.

[0260] The printing operation preferably also includes the type of resin impregnation machine, more preferably the type of resin impregnation machine and / or the specific configuration of the resin impregnation machine (e.g., temperature, resin type, pressure, etc.), so that the correct resin impregnation machine is correctly assigned to the decorative layer, and the correct printing area of ​​the present invention is also supplied with the correct printing operation. Other information in such a printing operation may also be provided, such as how the decorative panel must be cut, what type of mechanical joint must be ground, which other layers must be supplied, etc. All this information is sometimes referred to as metadata. Metadata can also be embedded in the decorative image.

[0261] The more metadata in the printing job, the easier it is to automate the entire manufacturing process of the decorative panel. Metadata can expose several settings: from color management settings and halftone settings to printing mode settings, resin impregnation machine settings, and cutting settings. Throughout the manufacturing process of the decorative panel, the printing job can be followed, also known as a print job tracking process. Post-processing of the decorative layer containing the inkjet-printed decorative image, such as resin impregnating the decorative layer along with other layers onto the decorative panel (if not performed in the resin impregnation step), applying an embossed structure to the decorative panel, cutting the decorative panel into decorative laminates, and grinding mechanical joints, such as tongues and grooves, on the decorative laminates, can be performed remotely for economic and ecological reasons, bringing these post-processing steps closer to the consumer and thus minimizing transport distances and emissions from the final product delivered to the consumer. This is an advantage of having a print job tracking system.

[0262] Another advantage is that accurate color conversion can be achieved regardless of whether the resin impregnation machine is assigned through analysis of the printing job. It has been found that when heat-setting decorative panels, the type and specific construction of the resin impregnation machine, such as a particular temperature setting, can affect the color of the decorative layer. The decorative workflow system can provide a color management system that takes into account the assignment of the resin impregnation machine.

[0263] The type and / or specific construction of the resin impregnation machine can be determined by analyzing the printing job. For example, the printing job may also contain details of the sender (such as a brand owner or printer), thereby allowing the decoration workflow system to analyze which type of resin impregnation machine should be used based on the sender's known wishes or predetermined user requirements. This analysis of the resin impregnation machine's type and / or specific construction is then incorporated into the decoration workflow system. Another example is analyzing the content of the decorative image to be printed, thereby allowing the decoration workflow system to determine the type and / or specific construction of the resin impregnation machine. This analysis of the resin impregnation machine's type and / or specific construction is then incorporated into the decoration workflow system. An example of analyzing decorative images (such as image analysis) could include the total coverage of the decorative image. Darker decorative images typically require a thicker resin layer, and resin impregnation includes a decorative layer for such images. This analysis (such as image analysis) can be performed in a pre-output inspection tool.

[0264] An overview of image analysis methods that can be performed through the decorative workflow system is published in PRATT, William K. Digital Image Processing: PIKS Scientific Inside. 4th ed. John Wiley, Part 5, “Image Analysis” [pp. 419-678].

[0265] Preferred image analysis methods included in the analysis of decorative image methods include: —Edge detection; and / or —Image segmentation; and / or —Shape analysis; and / or —Texture analysis.

[0266] Other examples of analysis of decorative images / printing jobs: —The size is determined, thereby assigning the correct type of resin impregnation machine capable of impregnating such a size.

[0267] —Delivery addresses for one or more decorative panels are determined, and these addresses are subsequently disclosed in the printing job. Based on the delivery address, the nearest resin impregnation machine is assigned to the printing job, thus reducing production time and transport costs. After analyzing the delivery addresses, the identification of the locations for resin impregnation is later incorporated into the printing job. Location identification can be determined from a database connected to a decorative workflow system containing the locations of several resin impregnation machines.

[0268] The structural settings determined from the analysis or incorporated into the printing operation can be marked on the decorative layer by text or, more preferably, by an identification code (such as a barcode or QR code). An identification code reader connected to the resin impregnation machine can read the identification code, and the controller can configure the resin impregnation machine according to the content of the identification code. The identification code is preferably applied via the web-based inkjet printing system of the present invention, and more preferably via the inkjet printhead included in the inkjet printhead unit (500), and thus applied together with one of the inks in the ink kit of the web-based inkjet printing system.

[0269] Decoration shop In a preferred embodiment, the cloud-based roll-to-roll painting solution can be incorporated into a decoration workflow system, enabling decorative panel service providers or purchasers to create and manage an online storage of decorative panels containing painted decorative images for manufacturing. Such a solution is referred to as a decorative storefront.

[0270] Preferably, the storefront is sold as a hosted cloud service, thus eliminating the need for high initial investments in servers, software, databases, or expensive symmetric internet connections. This reduces the cost of deploying storage and improves time-to-market.

[0271] The storefront can have an easily managed storage center that serves as the hub for establishing and tracking orders. Its dashboard ideally provides real-time feedback on the status of incoming and ongoing orders.

[0272] Decorative storefronts preferably include an online editor, where decorative panel service providers or editors can design or edit decorative images. This gives decorative panel service providers the ability to create innovative ways to personalize decorative panels.

[0273] Integrating decoration storefronts into a decoration workflow system can improve efficiency by saving time, for example, by automatically downloading and processing orders for decoration panels that contain depicted decoration images.

[0274] Graphics processing unit The drawing steps in the decoration workflow system are preferably performed by one or more graphics processing units (GPUs). These have been used for drawing computer graphics for many years. Today, due to their highly parallel architecture, they are also used for general-purpose tasks, making them more efficient than central processing units (CPUs). The GPU in this invention is an advantage, used not only for drawing decorative images but also for image analysis of decorative images and images captured from optical scanning systems. GPUs can be combined with CPUs to achieve even greater performance. In this way, the serial portion of the code runs on the CPU, while the parallel portion runs on the GPU. While CPUs with multiple cores are available for every new computer and allow for parallel computing, these are concentrated on having a few high-performance cores. GPUs, on the other hand, have an architecture consisting of thousands of lower-performance cores, making them particularly useful when large amounts of data must be processed.

Claims

1. A method for manufacturing decorative panels (331, 332), comprising the following steps: —In the first time period, inkjet printing is performed in a roll paper inkjet printing system to form a first decorative layer (301); as well as —The first decorative layer (301) is assigned to the first hot press (401); —During the second time period, inkjet printing is performed in the same roll-to-roll inkjet printing system to form a second decorative layer (302); and —The second decorative layer (302) is applied to the second hot press (402); —The first decorative layer (301) is hot-pressed into a decorative panel (331) on the first hot press (401); and —The second decorative layer (302) is hot-pressed into another decorative panel (332) on the second hot press (402); and The first time period and the second time period overlap; and The first hot press (401) and the second hot press (402) have different configurations, the different configurations being selected from: the size of the hot press, the maximum size of the layers that can be hot-pressed in the hot press, the inclusion of an embossed plate with a specific relief in the hot press, the minimum / maximum hot-pressing temperature of the hot press, the addition of an additional layer such as a protective layer at the hot press, and the location of the hot press; the method is adaptable to a variety of different methods for manufacturing decorative panels (331, 332) and to a variety of different sizes of decorative panels (331, 332). And the first and second decorative layers are printed in overlapping time periods using only a roll-to-roll inkjet printing system to shorten the manufacturing time of the decorative panels (331, 332).

2. The manufacturing method according to claim 1, wherein the first roll paper substrate and the second roll paper substrate are paper substrates, and each of the paper substrates has one or more ink receiving layers on its surface suitable for inkjet printing with water-based coloring inkjet inks.

3. The manufacturing method according to claim 2, wherein the outermost ink receiving layer is free of inorganic pigments or contains an inorganic pigment content less than that of the ink receiving layer between the paper substrate and the outermost ink receiving layer.

4. The manufacturing method according to claim 2, wherein the paper substrate is impregnated with a thermosetting resin before hot pressing.

5. The manufacturing method according to claim 3, wherein the paper substrate is impregnated with a thermosetting resin prior to hot pressing.

6. The manufacturing method according to claim 1, wherein the first roll paper substrate and the second roll paper substrate are thermoplastic substrates suitable for inkjet printing with UV-curable coloring inkjet inks.

7. The manufacturing method according to claim 4, wherein the thermosetting resin is selected from melamine-formaldehyde resin, urea-formaldehyde resin and phenol-formaldehyde resin.

8. The manufacturing method according to claim 7, wherein the water-based coloring inkjet ink comprises red inkjet ink containing a pigment selected from CI Pigment Red 254, CI Pigment Red 176 and CI Pigment Red 122 or a mixture thereof.

9. The manufacturing method according to claim 8, wherein, The first decorative layer (301) and / or the second decorative layer (302) are hot-pressed together with the core layer (321, 322) and the protective layer to form a decorative panel; wherein the core layer (321, 322) is selected from MDF, HDF or OSB.

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