EP3130473B1 - Method for producing decorative prints with identical quality independently from the applied printing method and an apparatus for carrying out the method - Google Patents

Description

The present invention relates to a method for producing decorative prints according to claim 1.

description

Decorated backing materials, e.g. Engineered wood panels are typically used as floor coverings or to cover walls and ceilings. For this purpose, the wood-based panels used as support materials were usually coated in the past with a decorative paper, the variety of differently patterned decorative papers were no limits or are.

As an alternative to the use of decorative papers on wood-based panels in the past, the direct printing of wood-based panels has developed as support materials, as a printing of paper and its subsequent lamination or direct coating accounts for the wood-based panel.

The printing techniques mainly used here are gravure printing and digital printing. The gravure printing process is a printing technique in which the elements to be imaged are in the form of depressions in a printing form which is inked before printing. The ink is primarily in the recesses and is due to contact pressure of the printing plate and adhesive forces on the object to be printed such. transfer a carrier material. In digital printing, on the other hand, the print image is transferred directly from a computer to a printing press such as a press. transferred to a laser printer or inkjet printer. This eliminates the use of a static printing form.

However, in the context of the technical development of printing technology for a wide variety of substrates, digital printing is becoming more and more important. While digital printing processes were initially used mainly in the graphics industry, such as advertising agencies, advertising manufacturers or printers, it is now becoming apparent that digital printing processes are also more common in other industries. There are many reasons for this, but there are two main arguments to let. Thus, digital printing enables the production of a print image with a particularly high quality through a higher resolution and also allows a wider range of applications with high flexibility. For example, in the WO 2011/029539 A1 describes a method of printing plastic films using a stationary head digital printer for small lot size production jobs.

The disadvantage of increased costs of digital printing technology per print, in particular in comparison with conventional printing processes such as gravure printing or offset printing, is increasingly becoming less important.

Despite the many advantages, the technically better and more demanding digital printing also poses problems that are particularly noticeable when desired or undesired combinations with other printing processes occur on products.

This can lead to irritation even in the first production stages, for example, when a customer selects or selects a suitable decoration. Namely, when a decor at a roll engraver or in a design studio initially as a digital printing with a correspondingly high resolution of 600 dpi (dots per inch) decommissioned and presented and for this decor then an engraved decor pressure roller for the role play only a resolution of about 60 to about 80 dpi, the two prints will show significant differences in a visual comparison.

One approach to solving this problem has been in the EP 1 858 244 presented. The method described here makes it possible to produce a same decoration on two different carrier materials using a uniform starting data record, wherein the decor is first printed on a first carrier material as a pattern print with an inkjet printer in a first printing line in digital printing and parallel or subsequently the same decor is printed on a second carrier material by means of a pressure roller in the gravure printing method in a second printing line. Accordingly, a digital printer is used for the withdrawal or production of a pattern print, and at least one identical digital output data record is used for the engraving of print rolls.

Digital printing today is performed almost exclusively using the CMYK color system. The CMYK color model is a subtractive color model, where the abbreviation CMYK stands for the three color components cyan, mangenta, yellow (yellow) and the black component Key as color depth. With this color system a color space (gamut) can be represented, which satisfies many requirements from most different areas. Nevertheless, the CMYK color space is a compromise, which means that certain colors can either not be created at all or the use of additional colors is necessary. This can result in color variations when converting a decor from a digital printing process to a gravure printing process, although the same dataset is used for both digital printing and gravure engraving. This problem is particularly evident where printing requires the production of a great deal of yellow and brown tones, such as the reproduction of wood decors in the furniture or laminate flooring industry. This can be countered by using the same pigments for the digital printer and for gravure printing. For the manufacturers of decorative wood-based panels this represents an unsolved problem.

Furthermore, products should be cheaper on the one hand through mass production and on the other hand customers expect a greater diversity, which is reflected, for example, in an almost infinite variety of décor. A significant problem is a prediction that a manufacturer z. B. has to make of decorative surfaces for everyday objects such as laminate flooring, as to the question of which new decors are accepted by customers and which are not.

When redesigning a collection, a decorative board manufacturer must remove a minimum amount of printed decor paper or printed finish film from each decor. The minimum amount of paper is usually about one ton, which is about 15,000 m ² . This decor paper must then be impregnated, pressed onto carrier plates and further processed. If exactly this décor does not succeed on the market, residual amounts are created at all stages of the value chain that can no longer be used. The resulting economic damage is significant. In addition, the color of the decor was set for at least one ton of paper.

One way to solve this problem would be to produce all decors exclusively as digital printing. However, this then has the serious disadvantage that these decors are considerably more expensive in terms of printing costs. In addition, the higher could be As a result of the higher resolution of digital printing, the quality level of the decors deviates from other non-digitally printed decors and thus leads to a loss of sales of conventionally printed substrates.

A further increasing trend is the ever smaller lot sizes. In principle, digital printing technology can also take this trend into account. Due to the high flexibility of digital printing, it is not only possible to print on paper or film webs, but also to directly print directly on carrier plates such as wood fiber boards. This can be skipped on the way to finishing on semi-finished or finished products, such as furniture panels, laminate floors or facade panels some value added levels, resulting in a further flexibility and simplification of manufacturing processes.

A particular challenge lies in a combination of different printing methods, because so far visible differences in a desired or unwanted combination of higher-quality digital prints in comparison with other printing processes. These are then often regarded as a quality defect and claimed.

The technical problem underlying the invention was therefore to offer a method for the production of decorative prints on substrates with the same quality or comparable quality appearance, regardless of whether the decor was created digitally or analogously.

This object is achieved by a method having the features of claim 1.

Accordingly, a method for the production of decorative prints of the same quality is provided on at least two substrates, the quality of the decorative prints is independent of the printing methods used, in particular regardless of the question of whether the applied printing method to a digital printing or a analog printing, such as gravure.

1. a) Bereitstellen von mindestens einem Druckmotiv;
2. b) Umwandeln des mindestens einen Druckmotivs in mindestens einen hochaufgelösten elektronischen Datensatz mit einer Auflösung von bis zu 1.200 dpi, bevorzugt 1.000 dpi, durch mindestens eine bildbearbeitende Software;
   b1) Anpassen des hochaufgelösten Datensatzes des Druckmotivs an Änderungen betreffend Dekor und/oder Farbe, wobei Schneide- und Identifizierungsmarkierungen als Verarbeitungsmittel für die zu bedruckenden Trägermaterialien in das Dekor eingebracht werden, und Elemente zur Individualisierung in den Datensatz integriert werden,
3. c) Reduzierung der Auflösung des mindestens einen hochaufgelösten elektronischen Datensatz auf bis zu 100 dpi, bevorzugt 60 bis 80 dpi, durch mindestens eine bildbearbeitende Software,
4. d) Erstellen von mindestens einem ersten Druckdekor auf mindestens einem ersten Trägermaterial unter Verwendung von mindestens einem Digitaldrucker mit dem mindestens einen auflösungsreduzierten elektronischen Datensatz;
5. e) Erstellen von mindestens einer Druckwalze für ein Tiefdruckverfahren unter Verwendung von mindestens einem auflösungsreduzierten elektronischen Datensatz, und
6. f) Erstellen von mindestens einem zweiten Druckdekor auf mindestens einem zweiten Trägermaterial unter Verwendung der mindestens einen Druckwalze.

The present inventive method comprises the steps

1. a) providing at least one print motif;
2. b) converting the at least one print motif into at least one high-resolution electronic data record with a resolution of up to 1200 dpi, preferably 1000 dpi, by at least one image-editing software;
   b1) adapting the high-resolution data set of the print motif to changes in decor and / or color, wherein cutting and identification marks are introduced as a processing means for the substrates to be printed in the decor, and elements for customization are integrated into the record,
3. c) reduction of the resolution of the at least one high-resolution electronic data record to up to 100 dpi, preferably 60 to 80 dpi, by at least one image-editing software,
4. d) creating at least a first printed decor on at least one first substrate using at least one digital printer having the at least one resolution reduced electronic data set;
5. e) preparing at least one printing roll for a gravure printing process using at least one resolution-reduced electronic data record, and
6. f) creating at least one second printing decor on at least one second carrier material using the at least one pressure roller.

The software used in steps b) and c) is preferably identical.

The present method thus employs an electronic data set reduced in resolution both for controlling a digital printer and for producing a printing roller / set of printing rollers and their use in a gravure printing process for decor-coating another substrate. Accordingly, the resolution and possibly the color of the prints is adapted starting from a same digital data record.

Preferably, the first printed decor applied by digital printing and the second low-pressure printed decor are identical, so that a direct comparison the print quality is given. Thus, it is possible to present a sample pattern with a specific decor made in digital printing to a customer and to convict after customer approval of this printing decor by means of the lower-cost printing without loss of quality in mass production.

As mentioned above, a print motif is first provided, typically using various designs as print motifs such as e.g. Veneers are used with wood grain, tile patterns, parquet imitations or fantasy patterns.

In a variant of the present method, the at least one print motif with the at least one image-processing software is not only converted into an electronic dataset, but also simultaneously edited to match the subject's initial and motivational end to form an endless motif.

The elements of the individualizations introduced in step b1) are preferably knotholes or cracks for wood decors, fossils or inclusions for stone decors or figures or toys for fantasy decors.

It is also possible to adapt the high-resolution data set of the printing motif or printing decoration and / or color changes. Thus, e.g. Markers as processing aids, e.g. Non-visible ink cutting or identification markers, such as IR ink, which are readable by means of appropriate detection devices. Of course, other changes or adjustments of the print motif under changes or additions to the record can be made.

The high-resolution electronic data record produced in step b) can be used for digital printing and includes data for controlling the digital printing. Use of such a high resolution data set in an analog method, e.g. the gravure printing method would not be possible.

Accordingly, it is therefore necessary to reduce the resolution of the at least one high-resolution electronic data set in accordance with step c) using at least one image-processing software, so that the data set can be used for the engraving of printing rolls.

The at least one first carrier material and the at least one second carrier material used in the present process may be identical or different and may be selected from a group comprising paper, glass, metal, films, wood-based materials, in particular MDF or HDF boards, veneers, lacquer layers , Plastic plates and inorganic carrier plates.

In a preferred embodiment of the present method, the number of pixels per unit area applied to the first substrate by digital printing is equal to the number of pixels per unit area applied to the second substrate by means of gravure printing. Accordingly, it is preferred that the number of pixels applied to the substrate per unit area be independent of the printing process used, i. It makes no difference whether digital printing or gravure printing is used.

In a further variant of the present method, the printing decor created by means of digital printing and the printing decor created by gravure printing using the printing roller are printed on uniformly pre-primed carrier materials.

The carrier materials may e.g. be pretreated by primer layer of a resin and / or a lacquer. In this case, an aqueous resin solution and / or a radiation-curable filler may be applied to the primer to be printed on the side of the substrate. As a primer, e.g. aqueous formaldehyde-containing resin solutions such as melamine-formaldehyde resin, urea-formaldehyde resin or melamine-urea-formaldehyde resin can be used. It is also possible to pre-coat or prime the backing material with UV filler and / or ESH filler and then cure this primer coat accordingly.

In a further preferred variant of the present method, as described, first of all a data set with reduced resolution is used for both the digital printing and for generating the set of rolls as a so-called standard data set. Subsequently, the decorate record can be provided with customizations electronically, e.g. for wood decors with knotholes or cracks, for stone decors with fossils or inclusions or for fantasy decors with figures or toys.

This individualized decorate record can be used in either a high resolution or a reduced resolution for digital printing. The question with which Resolution of the individualized record is essentially dependent on how the collections are positioned or whether through customization may be achievable a higher sales revenue. Thus, the customer could be offered the added benefit of higher resolution with a higher sales revenue. On the other hand, if the product is to be offered as cheaply as possible, a reduced resolution of the data set is preferably selected. At higher resolution, the performance of the printer drops significantly.

In the production line it is then possible to produce mixed print designs. Thus, a predetermined number of plates e.g. five plates are printed using the standard data set at low pressure, and a subsequent number of further plates, e.g. two plates, using the individualized data set to be printed in digital printing. So you can respond to customer requests and achieve better prices with the individualized decors.

In a further variant of the present method, the printing fluids used for digital printing and for deep printing have identical pigments, wherein solvents and binders of the printing fluids used can be different. The inks for the gravure printing process and the inks for the digital printing process have correspondingly the same pigment base, which leads to comparable or identical results in printing.

It is also possible to apply to the decor or decors at least one protective layer, in particular a layer comprising abrasion-resistant particles, natural fibers, synthetic fibers and / or other additives, wherein resins such as melamine-formaldehyde resin, or urea-formaldehyde resin , Acrylate resins and polyurethane resins can be used as suitable binders.

The abrasion-resistant particles are preferably selected from the group consisting of aluminum oxides, corundum, boron carbides, silicon dioxides, silicon carbides and glass beads. As natural and / or synthetic fibers in particular fibers are selected from the group containing wood fibers, cellulose fibers, wool fibers, hemp fibers and organic or inorganic polymer fibers are used.

As additives, conductive substances, flame retardants, luminescent substances and metals may be added. In this case, the conductive substances may be selected from the group comprising carbon black, carbon fibers, metal powder and nanoparticles, in particular Carbon nanotubes. It is also possible to use combinations of these substances. As flame retardants phosphates, borates, in particular ammonium polyphosphate, tris (tri-bromneopentyl) phosphate, zinc borate or boric acid complexes of polyhydric alcohols are preferably used. As luminescent substances are preferably fluorescent and / or phosphorescent substances on an inorganic or organic basis, in particular zinc sulfide and alkaline earth aluminates.

In a further embodiment of the present method, the printed substrate material which may be provided with a protective layer is further processed or finished in a short-cycle (KT) press. In the KT press, the resin layers are melted and the laminate is cured to a laminate. During further processing in the KT press, surface structures of the surface of the carrier material, such as a wood-based panel, can also be produced using a structured press plate, which optionally can be designed to match the décor (so-called decorsynchronous structure). For wood decors, the structures may be in the form of pore structures that follow the grain. For tile decors, the structures may be depressions in the area of joint fill lines enclosed by the decor.

The present method offers a number of advantages. Thus, the samples or selected substrates provided with printing decors can be presented to the customer immediately. It is possible to create any colors and to introduce a digital rework. Also, the decors or products can be produced with the appropriate decors in any amount and a fast delivery is possible without pressure roller production. It is also possible to use the master data record for premium products using the data record with the highest resolution, and residual stocks at different stages of the production process are avoided.

The method described here has the advantage that a rapid provision of color-matched products is possible and only later, depending on the market success of the product, the most favorable production method can be selected. The disadvantage of higher costs is limited to poorly performing decors or initial productions. The development of decors within the product life cycle can also be better taken into account. For example, a small amount is printed digitally for samples or samples, and the resulting large quantities are subsequently produced in gravure printing. At the end of the life cycle of a product, small quantities can be generated digitally. Another advantage is that in a production line, which has both the possibilities of low and digital printing, a decor can be processed individually and mixed non-individualized.

• mindestens ein Mittel, z.B. eine bildbearbeitende Software, zum Umwandeln von mindestens einem Druckmotiv in mindestens einen hochaufgelösten elektronischen Datensatz mit einer Auflösung von bis zu 1.200 dpi, bevorzugt 1.000 dpi;
• mindestens ein Mittel, z.B. eine bildbearbeitende Software, zum Reduzieren der Auflösung des mindestens hochaufgelösten elektronischen Datensatzes auf bis zu 100 dpi, bevorzugt 60 bis 80 dpi,
• mindestens eine erste Druckstraße mit einem Digitaldrucker zum Erstellen von mindestens einem ersten Druckdekor auf mindestens einem ersten Trägermaterial und der Verwendung des mindestens einen auflösungsreduzierten elektronischen Datensatzes, und
• mindestens eine zweite Druckstraße mit einer Druckwalze für ein Tiefdruckverfahren zum Erstellen von mindestens einem zweiten Druckdekor auf mindestens einem zweiten Trägermaterial, wobei die mindestens eine Druckwalze unter Verwendung von mindestens einem auflösungsreduzierten elektronischen Datensatz erstellt wurde, und wobei der auflösungsreduzierte elektronische Datensatz gleich oder verschieden sein kann von dem für den Digitaldruck in der ersten Druckstraße verwendeten auflösungsreduzierten elektronischen Datensatz.

The present method is carried out in a device for producing decorative prints of the same quality on at least two carrier materials from an original data set, the device comprising the following elements:

• at least one means, eg image processing software, for converting at least one print motif into at least one high-resolution electronic data set with a resolution of up to 1200 dpi, preferably 1000 dpi;
• at least one means, eg image processing software, for reducing the resolution of the at least high-resolution electronic data set to up to 100 dpi, preferably 60 to 80 dpi,
• at least one first printing line with a digital printer for creating at least a first printed decor on at least one first carrier material and the use of the at least one resolution-reduced electronic data set, and
• at least one second printing line having a printing roll for a gravure printing method for creating at least a second printing decor on at least one second substrate, wherein the at least one printing roller has been created using at least one resolution-reduced electronic record, and wherein the resolution-reduced electronic record may be the same or different from the resolution-reduced electronic data set used for digital printing in the first printing line.

As already described for the process, the support materials used may be the same or different.

Also, in the first and second printing lines, printing liquids having the same pigment base can be used for gravure printing and digital printing, that is, the printing fluids used can have identical pigments.

In a further variant, the present device comprises at least one means for applying a protective layer to the substrate provided with the respective printing decor. This means or device for applying a protective layer is preferably arranged after the first printing line or second printing line.

In a preferred embodiment, the present device comprises at least one short-cycle press for pressing the carrier material provided with the printing decor and the protective layer arranged thereon. In this case, each printing line can be assigned at least one short-cycle press or it is also conceivable that the carrier materials issuing from the first and second printing lines and each provided with a printing decor are fed to a single short-cycle press.

The invention will be explained in more detail below with reference to an embodiment.

embodiment

A veneer (1400 x 2070 mm) is scanned in a scanner with a resolution of 1000 dpi.

By aligning with image editing software, the transition at the beginning and end of the decor can be adjusted to create an endless decoration.

There are z. As well as editing the wood grains are made or integrated elements for customization such as knotholes, cracks, etc.

Furthermore, cutting, identification marks or other processing aids are applied. These can be realized in the case of digital printing with non-visible inks (IR ink), which are read later with corresponding detection devices.

Subsequently, the electronic data set is reduced by the image processing software to a resolution that is suitable for the engraving of printing rollers (60-80 dpi).

With this data set, first failure patterns are then created on a digital printer, which can be color-adjusted after consultation. Paper, foil, wood materials, veneers, lacquer layers, plastic plates, inorganic carrier plates, etc. can serve as carrier materials for the prints.

At the same time, rolls are used for the production of the decoration in the gravure printing process.

Later, decors that can be realized using gravure and digital printing will be printed on uniformly pre-primed substrates. It can also be a mixed pressure when using carrier plates. The standard data set is created in gravure printing and the individualized data set is produced with the digital printer. This makes it possible for. B. from a floor for a customer to produce a floor of a mixture of standard and individual planks.

The method is not limited to the production of wood reproductions. Any template can be digitized, edited and printed on a variety of substrates or pressed

Claims (11)

1. Method for producing decorative prints with identical quality on at least two carrier materials,
   comprising the steps

   a) providing at least one printing motif;

   b) converting the at least one printing motif into at least one high-resolution electronic data set with a resolution of up to 1200 dpi, preferably 1000 dpi, by at least one piece of image-processing software,

   b1) adapting the high-resolution data set of the printing motif to changes relating to decor and/or colour, cutting and identification markings being introduced into the decor as processing means for the carrier materials to be printed, and elements for individualisation being integrated into the data set,

   c) reducing the resolution of the at least one high-resolution electronic data set to up to 100 dpi, preferably 60 to 80 dpi, by means of at least one piece of image processing software,

   (d) creating at least one first printed decoration on at least one first carrier material by using at least one digital printer with the at least one resolution-reduced electronic data set,

   (e) creating at least one printing roll for a gravure printing process using at least one resolution-reduced electronic data set; and

   f) creating at least one second printed decoration on at least one second carrier material by using the at least one printing roll.
2. Method according to claim 1, characterized in that the at least one printing motif is processed with at least one piece of image-processing software for aligning the motif start and motif end forming an endless motif.
3. Method according to claim 1 or 2, characterized in that the introduced elements of the individualizations are knotholes or cracks for wood decors.
4. Method according to one of the preceding claims, characterized in that the at least one first carrier material and the at least one second carrier material are the same or different.
5. Method according to one of the preceding claims, characterized in that the first and second carrier materials are selected from a group comprising paper, glass, metal, foils, wood materials, in particular MDF or HDF boards, veneers, lacquer layers, plastic boards and inorganic carrier boards.
6. Method according to one of the preceding claims, characterized in that the number of image points per unit area applied to the first carrier material by means of digital printing is equal to the number of image points per unit area applied to the second carrier material by means of gravure printing.
7. Method according to one of the preceding claims, characterized in that the printed decoration produced by means of digital printing and the printed decoration produced by means of gravure printing by using the printing roll are printed onto uniformly pre-primed carrier materials.
8. Method according to one of the preceding claims, characterized in that an electronic standard data set is produced for the gravure printing using the printing roll, and an electronic individualized data set is produced for the digital printing.
9. Method according to one of the preceding claims, characterized in that the printing liquids used have identical pigments.
10. Method according to one of the preceding claims, characterized in that a protective layer is applied to the printed decoration or the printed decorations.
11. Method according to one of the preceding claims, characterized in that the carrier material that is printed and possibly provided with a protective layer is fed to a short-cycle press for further processing, in particular including structuring.