DE102019207277A1 - Method for producing a decorative surface, in particular a wooden workpiece - Google Patents

Abstract

A method for producing a decorative surface on a workpiece (1) is disclosed, comprising the following steps: feeding the workpiece (1), the surface of which has wood or wood fibers at least in some areas, to a cover substance application unit (10) and / or to a liquid application unit (20); - at least partial application of a cover substance (3) to the surface of the workpiece (1), the cover substance (3) being designed to at least partially cover the surface of the workpiece (1) at the points where it was applied to be sealed, the cover substance (3) preferably being designed to be digitally printable; and- applying a liquid (4) to the surface of the workpiece (1), wherein the liquid (4) is preferably colored and preferably contains dyes and / or color pigments and / or has the properties of a stain. Furthermore, a device for performing the method disclosed.

Description

The present invention relates to a method for producing a decorative surface of a workpiece and a device for carrying out the method.

State of the art:

According to the current state of the art, both solid wood floorboards and a so-called engineered floor, i.e. a multi-layer parquet or an artificial parquet, which is created by gluing a thin layer of wood, sometimes less than 1 mm, to a carrier board, become different colors by applying pigmented ones Liquids ("stain") generated.

These pickling liquids are brushed into the wood pores with so-called expeller rollers in order to also reach deeper points in the wood structure. According to the typical state of the art, pickling liquids are pigmented in such a way that they are at least partially transparent and the wood look underneath can still be seen.

With this method, for example, a so-called "smoked oak" is optically produced from a light-colored plank.

However, this manufacturing process only allows the entire surface of the workpiece to be treated.

According to a further state of the art, there are high-quality floors that are laid as light-colored real wood and in which certain patterns are then produced on site by pickling liquids, e.g. Checkerboard pattern or something similar. With this technique, after the floor has been laid, the installer has to mask it with adhesive tape (comparable to painter's tape) and leave certain areas open. The open areas are then soaked with pickling liquid, and the pickling is removed again after a certain exposure time.

This obviously very complex process then leads to certain patterns on the real wood that achieve a desired look in an interior. A similar manual procedure is also possible for furniture surfaces or table surfaces made of solid wood or a wood veneer or engineered wood (multi-layer parquet or multi-layer real wood, pressed wood).

This wood stained in this way with the above-mentioned possible pattern is produced according to the current state of the art either over the full surface of the wood or with manual masking and a great deal of manual effort.

The idea behind the method according to the invention is therefore to use a very cheap wood, e.g. a birch veneer to create an optical "mahogany look veneer".

The object of the present invention or of the method according to the invention is to find a simple and industrially feasible possibility of nevertheless generating certain desired patterns on a real wood surface without manual masking and thereby significantly reducing the time and costs per square meter.

This object is achieved by the subjects of the independent claims. Advantageous further developments are the subject of the subclaims.

• - Zuführen des Werkstückes, dessen Oberfläche zumindest in Teilbereichen Holz oder Holzfasern aufweist, zu einer Decksubstanzaufbringungseinheit und/oder zu einer Flüssigkeitsaufbringungseinheit;
• - mindestens teilweises Aufbringen einer Decksubstanz auf die Oberfläche des Werkstückes, wobei die Decksubstanz dazu ausgebildet ist, die Oberfläche des Werkstückes an den Stellen an denen sie aufgebracht wurde, mindestens teilweise zu versiegeln, wobei die Decksubstanz vorzugsweise digital verdruckbar ausgebildet ist; und
• - Aufbringen einer Flüssigkeit auf die Oberfläche des Werkstückes bzw. auf die Decksubstanz, wobei die Flüssigkeit vorzugsweise eingefärbt ist und vorzugsweise Farbstoffe und/oder Farbpigmente enthält und/oder Eigenschaften einer Beize aufweist.

According to the invention, a method for producing a decorative surface on a workpiece is provided with the following steps:

• - Feeding the workpiece, the surface of which has wood or wood fibers at least in some areas, to a cover substance application unit and / or to a liquid application unit;
• - At least partial application of a cover substance to the surface of the workpiece, the cover substance being designed to at least partially seal the surface of the workpiece at the points where it was applied, the cover substance preferably being digitally printable; and
• - Application of a liquid to the surface of the workpiece or to the covering substance, the liquid preferably being colored and preferably containing dyes and / or colored pigments and / or having the properties of a stain.

The interaction of the covering substance with the wood substrate is preferably limited to physical adhesion. The resulting attachment force of the covering substance on the surface of the workpiece is sufficient for the subsequent pickling process. The permeability of the liquid through the cover substance can preferably be controlled by the printed application amount of the cover substance. With a high application rate, the wood surface is almost completely sealed, with a lower application only partial masking; Wood pores, medullary rays and exposed areas are increasingly colored.

The control of the application amount of the covering substance is possible in terms of process technology. This can be implemented, for example, in a correspondingly designed cover substance application unit his. The cover substance application unit uses digital and / or analog printing technology for this purpose.

The surface adhesion of the acidic liquid on the wood is preferably also based on physical adhesion. A characteristic of this is preferably the inadequate weathering resistance of dye stains, which is why the wood surface is usually still oiled or given a top coat.

After the step of at least partially applying the covering substance, a step for drying and / or fixing the covering substance is preferably carried out. This is preferably done by supplying heat and / or by radiation curing the cover substance. The supply of heat to the cover substance can preferably take place by means of hot air and / or by means of infrared radiation. For radiation curing, UV radiation can preferably be radiated onto the cover substance. For this purpose, the covering substance is preferably fixed on the surface of the workpiece. As a result of the fixation, the covering substance is connected to the surface of the workpiece, so that there is an increased adhesive force between the covering substance and the surface of the workpiece. The drying and / or fixing is preferably equivalent to a partial, particularly preferably a complete, hardening of the covering substance.

After the step of applying the liquid, a further step is preferably carried out in which the liquid is expelled by distributing the liquid, preferably mechanically, particularly preferably with a expeller unit, into the wood pores. This preferably ensures better absorption of the liquid by the surface of the workpiece. The liquid is actively expelled into the wood pores, a portion of the liquid preferably being removed again from the surface of the workpiece. This portion is preferably not absorbable by the workpiece, since the workpiece is already saturated by absorbing the liquid. The expulsion takes place preferably by means of a brush, particularly preferably by means of a roller brush.

Preferably, after the step of applying the liquid and / or expelling the liquid, a further step is carried out by which the liquid is dried. The drying takes place preferably by means of supply of heat and / or radiation curing. The supply of heat to the liquid can preferably take place by means of hot air and / or by means of infrared radiation. For radiation curing, UV radiation can preferably be radiated onto the cover substance.

A further step is preferably carried out in which the covering substance is removed again. This is preferably done by grinding the surface of the workpiece, particularly preferably also removing material of the workpiece, which advantageously creates a uniformly treated surface of the workpiece.

The covering substance is preferably at least partially applied using an at least partially transparent ink. A highly transparent ink which does not contain any pigments is particularly preferably used for this purpose.

The at least partial application of the cover substance is preferably carried out according to a digital template. This is preferably done in such a way that after the liquid has been applied, it is only accepted by the underlying wooden surface of the workpiece in the non-printed areas or is accepted less strongly in the printed areas than in the non-printed areas. The covering substance advantageously acts as a seal for the surface of the workpiece against the liquid. The cover substance can therefore advantageously be applied to the surface of the workpiece in any pattern, so that the surface can be masked in any pattern. Subsequently, at least one unmasked, that is to say exposed, area of the surface of the workpiece can be brought into contact with the liquid, the liquid optically changing the surface of the workpiece in this area. Specifying a masking pattern using a digital template in particular has the advantage of being able to switch quickly between different patterns, so that a large number of different patterns or even completely individual, non-repetitive representations can be generated in a short time.

The wood surface underneath is preferably not completely covered in color by the liquid at the points at which the surface of the workpiece is not covered with the covering substance. Instead, the underlying wood pores, knotholes or other wood optics can preferably still be seen through a partially transparent layer of the liquid.

The liquid preferably allows the wood grain to stand out more clearly on the entire surface of the workpiece, with the resulting color differences between open-pore and closed-pore parts of the wood surface being greater in the masked areas than in the non-masked areas.

The at least partial application of the covering substance and / or the application of the liquid to the surface of the workpiece are / is preferably carried out at least one more time. In this case, an optical influence or change in the surface of the workpiece can advantageously be achieved in that the liquid is applied several times at some points. The covering substance can also be applied in a second pass to previously unmasked areas of the surface of the workpiece, so that the masking is changed before the liquid is applied a second time. As a result, it is advantageously achieved that areas on the surface of the workpiece come into contact with the liquid less often than others, since these are now sealed by the cover substance applied later when the liquid is applied again.

A further application could preferably also consist in coloring the wood or the wood fibers of the workpiece over the entire surface right at the beginning and then removing the excess, preferably then slightly sanding it if necessary. Only then is the cover substance applied according to the desired masking pattern and colored a second time. The overall color impression obtained is preferably a lower contrast between strong and less pronounced pigmentation.

In a second application, the liquid is preferably exchanged for another liquid with a different composition with regard to dyes and / or color pigments and / or stain properties.

The application of the liquid to the surface of the workpiece is preferably carried out at least one more time, the liquid being identical to the previous application each time, at least in terms of the dyes and / or color pigments it contains, the application at least to one point on the surface of the workpiece done several times. In this way, a more intensive optical change of the workpiece surface can be achieved. It is particularly preferable for the workpiece or the liquid to be dried between two application steps.

The step of applying the liquid is preferably carried out at least once before the at least partial application of the covering substance. In this way, the surface of the workpiece can be changed by the liquid in partial areas or also over the entire area before the covering substance is applied.

Before applying the liquid, a step is preferably carried out in which the surface of the workpiece is roughened at least partially, preferably over the entire area, the roughening preferably being carried out mechanically and / or chemically. The mechanical roughening is preferably carried out with a rubbing and / or grinding device. The chemical roughening is preferably carried out with a chemical which is designed to detach constituents of the wood fibers or even entire wood fibers from the workpiece. This is done, for example, by means of etching. The roughening has the advantageous effect that the capacity of the workpiece, at least on its surface, for the liquid is increased, so that the liquid or components contained therein, e.g. Color pigments, can more easily penetrate the workpiece.

The covering substance is preferably at least partially applied by means of digital printing technology and / or by means of analog printing technology. Digital printing technology is preferably to be understood as meaning inkjet or digital print heads which, particularly preferably, can be arranged over the entire width of the workpiece in order to be able to reach the entire surface of the workpiece as far as possible. Analogous printing technology is preferably to be understood as a printing roller which is designed to apply the covering substance by rolling it onto the surface of the workpiece according to a specific pattern.

The underlying cover substance is preferably applied between 1 g / m ² and 10 g / m ² , particularly preferably between 3 g / m ² and 8 g / m ² .

A further step is preferably carried out in which at least the liquid and / or the covering substance is removed from the surface of the workpiece. The removed liquid is preferably excess liquid which can no longer be absorbed by the workpiece, since it is already saturated. The liquid and / or the covering substance can preferably be actively removed. Active removal can in particular be understood to mean mechanical removal of the covering substance and / or the liquid with a brush and / or with a plane and / or with a grinding device. Particularly preferably, the material of the workpiece is also removed. This can also be understood to mean heating and / or evaporation of the covering substance and / or the liquid. A heat source such as e.g. a heater and / or a fan, which is designed to deliver hot air, and / or an infrared radiator can be used.

The liquid is preferably applied over the entire surface of the workpiece.

• - eine Decksubstanzaufbringungseinheit, die dazu ausgebildet ist, eine Decksubstanz mindestens teilweise auf die Oberfläche des Werkstücks aufzubringen, wobei die Decksubstanz dazu ausgebildet ist, die Oberfläche des Werkstücks an den Stellen an denen sie aufgebracht wurde, zu versiegeln;
• - eine Flüssigkeitsaufbringungseinheit, die dazu ausgebildet ist, eine Flüssigkeit auf die Oberfläche des Werkstücks aufzubringen, wobei die Flüssigkeit vorzugsweise eingefärbt ist und vorzugsweise Farbstoffe und/oder Farbpigmente enthält und/oder Eigenschaften einer Beize aufweist;
• - eine Steuereinheit, die dazu ausgebildet ist, die Vorrichtung entsprechend anzusteuern, um eine Durchführung des Verfahrens wie oben beschrieben zu bewirken.

According to the invention, a device for performing the method according to one of the preceding claims is also provided, comprising:

• a covering substance application unit which is designed to apply a covering substance at least partially to the surface of the workpiece, the covering substance being designed to seal the surface of the workpiece at the locations where it was applied;
• a liquid application unit which is designed to apply a liquid to the surface of the workpiece, the liquid preferably being colored and preferably containing dyes and / or color pigments and / or having the properties of a stain;
• a control unit which is designed to control the device accordingly in order to carry out the method as described above.

The device preferably also has a fixing unit which is designed to dry the cover substance and / or the liquid, the fixing unit preferably having a fan and / or a heat source and / or a UV radiation source for this purpose.

The device preferably also has a preparation unit which is designed to prepare, in particular roughen the surface of the workpiece, the preparation unit preferably having a roughening roller and / or a grinding device and / or a dispensing device for dispensing a roughening substance, such as a grinding paste . A sandblasting device or the like can also be provided.

The device preferably also has a distributor unit which is designed to distribute the liquid on the surface of the workpiece, the distributor unit preferably having a brush for this purpose.

Preferably, the device also has a post-processing unit which is designed to post-process the workpiece at least after the application of the covering substance and / or the liquid, the post-processing unit preferably having a grinding and / or planing device for this purpose.

Preferably, the device also has a coating unit which is designed to coat the surface of the workpiece. The coating can take place, for example, with a sealing lacquer layer, which is preferably applied to the workpiece in a last working step. For this purpose, the coating unit preferably has a casting device which is designed to form a lacquer curtain through which the workpiece is guided. Alternatively or additionally, the coating unit has an application roller which rolls off the surface of the workpiece and applies the paint there. Alternatively or additionally, the coating unit has an immersion tank, the workpiece being at least partially immersed in this immersion tank for coating with paint. As an alternative or in addition, the coating unit has digital printing technology which is designed to seal the workpiece by applying lacquer.

The device preferably also has a transport unit which is designed to feed the workpiece to at least some of the individual units, as described above. For this purpose, the transport unit preferably has a transport belt.

The transport unit is preferably designed to feed the workpiece at least one more time to at least one of the individual units described above. In this way, method steps can be carried out several times with a single unit without having to provide a further unit for the same method step.

The device preferably has at least one of the units described above a second time. In this way, it is possible to carry out a method step a second time at a later point in time of the method by providing a further unit.

• 1a bis 1c eine Ausführungsform des erfindungsgemäßen Verfahrens,
• 2a bis 2c Möglichkeiten, die Decksubstanz bzw. die Flüssigkeit aufzubringen, und
• 3 eine prinzipielle Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens.

The invention is explained in more detail below with reference to the accompanying drawings. Show it:

• 1a to 1c an embodiment of the method according to the invention,
• 2a to 2c Possibilities of applying the covering substance or the liquid, and
• 3 a basic device for performing the method according to the invention.

1a to 1c show a first embodiment of the method according to the invention.

In 1a is a workpiece 1 Shown in the side view, here as a plate-shaped workpiece 1 is trained. The workpiece 1 contains at least in parts of the surface real wood or wood fibers.

On the upward facing surface of this workpiece 1 becomes a cover substance 3 applied. The application of the covering substance 3 takes place in such a way that at least parts of the surface of the workpiece 1 from the covering substance 3 are covered. The result of this application is in 1b shown. This is where the covering substance works 3 on the surface of the workpiece 1 as a sealer so that the surface of the workpiece 1 at the areas where the covering substance 3 applied, is sealed. The surface is thus masked for the next work step, ie there are partial areas of the surface of the workpiece 1 still free.

In a further step, a liquid is now made 4th on the surface of the masked workpiece 1 upset. The liquid 4th only comes with the exposed, i.e. not masked, areas of the surface of the workpiece 1 in contact. The one through the covering substance 3 sealed areas of the surface of the workpiece 1 however, do not come with the liquid 4th in contact. This result is in 1c shown.

In an alternative embodiment, the surface of the workpiece is masked 1 through the covering substance 3 not completely given ("open pores"), so that the liquid 4th can partially penetrate at the masked areas, but reduced in amount compared to the unmasked areas.

The liquid 4th is designed to be the surface of the workpiece 1 , especially in interaction with the real wood or with the wood fibers of the surface, to change at least optically upon contact. This interaction or optical change occurs only in the areas where the fluid is active 2 based on the areas of the surface of the workpiece 1 that with the liquid 4th are in contact in the workpiece 1 extend into it. In this way, the workpiece can be visually changed 1 can be achieved as such.

In an alternative embodiment, in the other areas of the surface (not in the liquid effective areas 2 ) an interaction with the liquid 4th take place, but in a vs. the places 2 reduced dimensions.

In a special embodiment, the covering substance penetrates 3 also partially in the workpiece 1 one.

2a to 2c show alternative possibilities in the 1a to 1c to achieve the intermediate results shown.

The application of the covering substance 3 takes place in the embodiment shown in the form of droplets 3a , which are marked here with a dashed border. This can be done, for example, using digital printing technology such as a digital print head 11 , respectively. Thus, the droplet delivery, in particular with regard to the delivery volume of the droplets 3a actively influenced. The masking of the surface of the workpiece 1 the cover substance is thus characterized by a high variability of the masking pattern. The cover substance 3 is designed here, for example, as a digitally printable ink or digitally printable paint.
Alternatively or additionally, the application of the covering substance can be used 3 can also be done using analog printing technology, as in 2 B shown. The cover substance 3 can, for example, as ink or lacquer, by means of an application roller 12 on the surface of the workpiece 1 be applied. The order role 12 rolls on the surface of the workpiece 1 and leaves the covering substance 3 on the surface to mask them.

In summary, the covering substance can preferably be applied using printing techniques. Ideally, but not necessarily, digital printing technology is used for more complex masking.

The application of the liquid 4th can be done over a large or full area, for example. In 2c is an example of a pouring device 21st shown making a curtain made up of the liquid 4th generated by the one with the covering substance 3 masked workpiece 1 is conveyed through. The pouring device 21st has a reservoir in which the liquid 4th is stored and from which this, for example by means of a pump or as shown by means of a conveyor roller, on the surface of the workpiece 1 is promoted.

Another option (not shown) is the liquid 4th to apply, can be realized by a plunge pool in which the workpiece 1 is immersed at least with the masked surface.

In a further embodiment (not shown) the liquid 4th applied to the masked surface by a roller application process.

3 shows a basic device for performing the method according to the invention.

It is a top coat application unit 10 shown, which is designed to be the cover substance 3 on a workpiece 1 as in the 1a to 2c shown to apply. For this purpose, the cover substance application unit 10 for example a digital print head 11 , as in 2a shown, or an order roll 12 , as in 2 B shown on.

The cover substance application unit 10 downstream is a liquid application unit 20th provided, which is designed to the liquid 4th on the surface of the workpiece 1 to raise. For this purpose, the liquid application unit 20th for example a pouring device 21st , as in 2c shown, or a plunge pool, or a roller application unit.

There is also a fixation unit 40 shown between the cover substance application unit 10 and the liquid application unit 20th is provided. The fixation unit 40 is designed to dry the cover substance 3 perform before the liquid 4th is applied. To this end, the fixing unit 40 for example a nozzle channel, the hot air on the surface of the workpiece 1 or on the covering substance 3 lets flow. Alternatively or additionally, a heat source in the form of an infrared radiation source or a heater can also be provided around the cover substance 3 to dry. The fixation unit 40 can also have a UV radiation source in order to harden the cover substance or on the surface of the workpiece 1 to fix.

In front of the cover substance application unit 10 is a preparatory unit 50 provided, which is designed to the surface of the workpiece 1 to prepare for the further procedural steps. For example, a roughening roller or a grinding device can be provided here, which is used to mechanically roughen the surface of the workpiece 1 are trained. Alternatively or in addition, a dispensing device can also be provided here, which is designed to apply a cleaning agent, for example a chemical substance such as an acid, to the surface of the workpiece 1 to raise. For example, the cleaning agent interacts with the wood fibers of the workpiece 1 achieved that these change accordingly that the surface of the workpiece 1 becomes rougher, so that in particular an absorption of the liquid 4th is facilitated.

The liquid application unit 20th is a distributor unit 60 downstream, which is designed, the liquid 4th on the surface of the workpiece 1 to expel or into the surface of the workpiece 1 to incorporate. The distributor unit 60 can do this mechanically, for example. To this end, the distributor unit 60 for example a brush or roller brush that touches the surface of the workpiece 1 comes into contact and the liquid moves relative to it 4th distributes or incorporates. The distributor unit 60 can also be designed in the form of several rotary brushes (with an axis perpendicular to the surface of the workpiece). Further alternative embodiments are also conceivable.

After the distributor unit 60 is a post-processing unit 70 provided, which is designed to rework the surface of the workpiece. This can be done mechanically, for example. For this purpose, a grinding device can be provided which is designed to treat the surface of the workpiece 1 , especially the covering substance on it 3 and / or liquid 4th , to remove. The material of the workpiece is also preferably used 1 even removed to the optical change of the workpiece 1 moving through the liquid 4th has set in deeper layers to expose.

Furthermore, a coating unit 80 be provided, which is designed to the surface of the workpiece 1 to coat. This can be done, for example, with a varnish that is applied over the entire surface, whereby this preferably results in a final sealing of the workpiece 1 is made so that the optically modified surface of the workpiece 1 is protected. The lacquer for sealing is therefore at least partially transparent. Acrylate-containing UV-curing lacquers as well as oils or waxes can be used as sealing materials. Water-based paint systems with subsequent thermal drying are also conceivable.

All units listed here 10 , 20th , 30th , 40 , 50 , 60 , 70 , 80 are by a transport unit 90 connected to each other in such a way that the workpiece 1 can be transported to the individual units. The transport unit 90 for example a conveyor belt, with the units 10 , 20th , 30th , 40 , 50 , 60 , 70 , 80 are arranged on the conveyor belt.

The device also has a control unit 30th on to the individual units 10 , 20th , 30th , 40 , 50 , 60 , 70 , 80 and the transport unit 90 to be controlled so that the method according to the invention can be carried out with the device. The control unit 30th for example a control means in the form of a control device which is designed by means of program code to carry out the method according to the invention.

The fixation unit 40 , the preparatory unit 50 , the distributor unit 60 , the post-processing unit 70 , the coating unit 80 and the transport unit 90 are only available as Understand optional units that can also be omitted. The device obtained in this way then only has the cover substance application unit 10 , the liquid application unit 20th as well as the control unit 30th on. The process steps essential to the invention can also be carried out with such a device.

A feed of the workpiece 1 to the individual units 10 , 20th , 30th , 40 , 50 , 60 , 70 , 80 through the transport unit 90 is also not absolutely necessary, as the units 10 , 20th , 30th , 40 , 50 , 60 , 70 , 80 can be designed, for example, to the workpiece 1 to move.

Also is the order of the units shown 10 , 20th , 30th , 40 , 50 , 60 , 70 , 80 not absolutely necessary. Rather, other arrangements can also be provided here. The fixation unit 40 can for example be behind the liquid application unit 20th be provided. So it is not only capable of covering the substance 3 but also the liquid 4th , or just the liquid 4th to fix, as explained above.

Can also be in front of the cover substance application unit 10 a liquid application unit 20th be provided to the liquid 4th also on the unmasked surface of the workpiece 1 to raise.

The trigger for the present invention was the surprising finding that ink, which was applied to partial areas of a workpiece made of real wood, then acts as a covering substance against a liquid, here a stain or a pigmented liquid. In particular, a surprisingly positive effect of the printed ink was that the fiber structure of the wood surface underneath was not completely lost. This means that even in the areas of the surface masked by the ink, the wood structure was more clearly visible due to partial penetration of the stain than before the stain was applied. Thus, despite the partial masking of the surface as a whole, the wood structure became much clearer, which was a very desirable effect.

Therefore, for a more detailed understanding of the invention, specific embodiments of the invention are finally described with reference to the drawings explained above, which are to be assigned to this specific application.

In a special embodiment of the invention, a workpiece 1 , the surface of which consists at least partially of real wood, fed to a printing station in which the surface of the workpiece 1 in whole or in part with a covering substance 3 is printed in the form of a digitally printable ink. A pigmented liquid is then applied to this printed surface 4th applied, the pigmented liquid 4th in particular comes into contact with areas that are not with the covering substance 3 are printed. Between the first printing with the cover substance 3 and the application of the pigmented liquid 4th Drying can be carried out using hot air, infrared and / or radiation curing. The pigmented liquid applied after possible drying 4th is mechanically inserted into the pores of the real wood on the surface of the workpiece with a distributor brush 1 brought in. The pigmented liquid applied in this way can then be used 4th , which preferably has caustic properties, are dried. In a further step, the surface of the workpiece produced in this way can 1 be sanded in such a way that the printed cover substance 3 is removed again and only the color pigments that have penetrated deeper into the wood structure remain, which creates a printed image.

In a further embodiment, a second application of a liquid can 4th also using a liquid 4th in the form of a highly transparent ink without any pigments.

In a further embodiment, the pigmented liquid can 4th in the places where the wood surface does not interfere with the covering substance 3 has been commissioned to only partially cover the wood surface underneath, so that the wood pores, knotholes and other wood optics can still be seen through a transparent layer.

The process steps for paint and liquid application are repeated several times, but at least twice, with the pigmented liquid 4th in the second application step with another pigmented liquid 4th be exchanged with other color pigments so that a multi-colored or at least two-tone image is created.

In a further embodiment, the process steps for applying paint and liquid are repeated several times, but at least twice, with the pigmented liquid 4th contains the same color pigments as those of the previous process steps and so other color shades can be achieved in some places by double application.

The liquid 4th has as a stain in a specific embodiment a vapor pressure at 20 ° C of 23 hPA, a density at 20 ° C of 1.01 g / cm ³ , a kinematic viscosity at 20 ° C of 12 s (according to DIN 53211/4). It also contains 1.8% organic solvents, 92.7% water and the solids content is 5.4%.

The cover substance 3 is designed in a specific embodiment as Himalia03 ™ ink.

This has a density at 20 ° C of 1.09 g / cm ³ , a surface tension of 16 to 39 dynes / cm, a kinematic viscosity at 20 ° C of 16 s (after DIN 53211/4 ) on.

The nominal volume of the droplets 3a from this cover substance 3 is 6 to 42 pL (using an Xaar GS6 ™ printhead). Depending on the working window, this volume can be increased to 8 to 56 pL.

The main components are: <40 wt% 2- (2-ethoxyethoxy) ethylene acrylate, <40 wt% trimethylolpropane, ethoxylated, esterified with acrylic acid, <40 wt% dipentaerythritol hexaacrylate. Furthermore, it contains no organic solvents, no water, no pigment or dye.

The covering substance is applied using digital printing technology 3 (Density 1.09 g / L at 20 ° C) from 1.3 g / m ² (Level1) to 8.9 g / m ² (Level7). In this case, the level specification relates to a control of print heads in a digital application device.

In a special version, the covering substance also penetrates 3 due to the low viscosity (kinematic viscosity 16 s, DIN 53211/4, 20 ° C) and the pronounced capillary action of the wood fibers in the wood substrate.

The beginning of the boiling of the covering substance 3 in is at 101 ° C and, according to the standard, does not hold any UV initiators. The covering substance 3 However, it is compatible with the addition of a UV initiator and capable of photopolymerization. With a completely crosslinked cover substance, the scratch hardness is not greater than 3 N.

List of reference symbols

1

workpiece

2

Fluid range

3

Cover substance

3a

droplet

4th

liquid

10

Cover substance application unit

11

Digital print head

12

Order role

20th

Liquid application unit

21st

Pouring device

30th

Control unit

40

Fixation unit

50

Preparation unit

60

Distributor unit

70

Post-processing unit

80

Coating unit

90

Transport unit

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Non-patent literature cited

• DIN 53211/4 [0081]

Claims (20)

Method for producing a decorative surface on a workpiece (1) with the following steps: - Feeding the workpiece (1), the surface of which has wood or wood fibers at least in partial areas, to a cover substance application unit (10) and / or to a liquid application unit (20); - At least partial application of a cover substance (3) to the surface of the workpiece (1), the cover substance (3) being designed to at least partially seal the surface of the workpiece (1) at the points where it was applied, wherein the cover substance (3) is preferably designed to be digitally printable; and - Application of a liquid (4) to the surface of the workpiece (1), the liquid (4) preferably being colored and preferably containing dyes and / or color pigments and / or having the properties of a stain. Procedure according to Claim 1 , wherein after the step of at least partial application of the cover substance (3), a step of drying the cover substance (3) is carried out, preferably by means of heat supply and / or radiation curing of the cover substance (3). Method according to one of the above claims, wherein after the step of applying the liquid (4) a further step is carried out in which the liquid (4) is expelled by the liquid (4), preferably mechanically, with a expeller unit (60) is distributed into the pores of the wood, thus ensuring better absorption of the liquid (4) through the surface of the workpiece (1). Method according to one of the above claims, wherein after the step of applying the liquid (4) and / or expelling the liquid (4) after Claim 3 a further step is carried out by means of which the liquid (4) is dried, preferably by means of supply of heat and / or radiation curing. Method according to one of the above claims, wherein a further step is carried out in which the covering substance (3) is removed again, preferably by grinding the surface of the workpiece (1). Method according to one of the above claims, wherein the at least partial application of the covering substance (3) is carried out using an at least partially transparent ink, preferably using a highly transparent ink which does not contain any pigments. Method according to one of the above claims, wherein the at least partial application of the covering substance (3) takes place according to a digital template, preferably in such a way that after the application of the liquid (4) it is only removed from the underlying wooden surface of the workpiece ( 1) is accepted, or is accepted less strongly in the printed areas than in the unprinted areas. Method according to one of the above claims, wherein the liquid (4) does not completely cover the underlying wood surface in color at the places where the surface of the workpiece (1) is not covered with the covering substance (3) Method according to one of the above claims, wherein the liquid (4) on the entire surface of the workpiece (1) allows the wood grain to emerge more clearly, the resulting color differences between the open-pore and closed-pore parts of the wood surface (1) in the masked areas are larger than in the non-masked areas. Method according to one of the above claims, wherein the at least partial application of the cover substance (3) and / or the application of the liquid (4) to the surface of the workpiece (1) are / is carried out at least one more time, preferably the liquid (4) in the event of a second application, it is exchanged for a different liquid with a different composition with regard to dyes and / or color pigments. Method according to one of the above claims, wherein the application of the liquid (4) to the surface of the workpiece (1) is carried out at least one more time, and the liquid (4) is carried out each time at least with regard to the dyes and / or color pigments contained is identical to the previous application, the application being carried out several times at least at one point on the surface of the workpiece (1). Method according to one of the above claims, wherein the step of applying the liquid (4) is also carried out at least once before the at least partial application of the covering substance (3). Method according to one of the above claims, wherein before the application of the liquid (4) a step is carried out which roughen the surface of the workpiece (1) at least partially, preferably over the entire area, the roughening preferably being done mechanically and / or chemically. Method according to one of the above claims, wherein the at least partial application of the cover substance (3) takes place by means of digital printing technology and / or by means of analog printing technology. Method according to one of the above claims, wherein a further step is carried out in which the liquid (4) and / or the covering substance (3) is removed from the surface of the workpiece (1). Method according to one of the above claims, wherein the liquid (4) is applied over the entire surface of the workpiece (1). Device for carrying out the method according to one of the preceding claims, comprising: a cover substance application unit (10) which is designed to apply a cover substance (3) at least partially to the surface of the workpiece (1), the cover substance (3) designed to do so is to seal the surface of the workpiece (1) in the places where it was applied; - A liquid application unit (20) which is designed to apply a liquid (4) to the surface of the workpiece (1), the liquid (4) preferably being colored and preferably containing dyes and / or color pigments and / or properties of a stain having; - A control unit (30) which is designed to control the device accordingly in order to carry out the method according to one of the Claims 1 to 15th to effect. Device according to Claim 17 , further comprising: a fixation unit (40) which is designed to dry the cover substance (3) and / or the liquid (4), the fixation unit (40) for this purpose preferably being a fan and / or a heat source and / or has a source of UV radiation; and / or - a preparation unit (50) which is designed to prepare, in particular roughen the surface of the workpiece (1), the preparation unit (50) preferably having a roughening roller and / or a grinding device and / or a dispensing device for dispensing a Has rough substance; and / or - a distributor unit (60) which is designed to distribute the liquid (4) on the surface of the workpiece (1), the distributor unit (60) preferably having a brush for this purpose; and / or - a post-processing unit (70) which is designed to post-process the workpiece (1) at least after the application of the covering substance (3) and / or the liquid (4), the post-processing unit (70) preferably having a grinding and / or has planing device; and / or - a coating unit (80) which is designed to coat the surface of the workpiece (1); and / or - a transport unit (90) which is designed to feed the workpiece (1) to the individual units (10, 20, 30, 40, 50, 60, 70, 80), the transport unit (90) preferably for this purpose has a conveyor belt. Device according to Claim 18 , the transport unit (90) being designed to feed the workpiece (1) to at least one of the individual units (10, 20, 30, 40, 50, 60, 70, 80) at least one more time. Device according to one of the Claims 17 to 19th wherein the device has at least one of the units (10, 20, 30, 40, 50, 60, 70, 80) one more time.

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