DE102021121527A1 - Device and method for patterning a workpiece - Google Patents

Abstract

The invention relates to a device (1) for patterning a workpiece (2), which preferably consists at least partially of wood, wood materials, plastic or the like, comprising: at least one printing unit (10) for printing on a surface (2'), in particular a narrow surface , the workpiece (2), a conveyor device (4) for bringing about a relative movement between the workpiece (2) and the printing unit (10), and a feed unit (20) for feeding at least two print components to the printing unit (10), with upstream of the Printing unit (10), a mixing unit (30) for mixing the components supplied by means of the feed unit (20) and for delivering the mixture to the printing unit (10) is provided.

Description

technical field

The invention relates to a device and a method for sampling a workpiece, which preferably consists at least partially of wood, wood-based materials, plastic or the like.

State of the art

In the furniture and component industry, workpieces are often made of wood or wood-based materials, such as chipboard, which are coated and patterned on their surface. In this case, the coating itself can already be patterned, so that a separate patterning process can be dispensed with. On the other hand, it is also known to provide the coating with the desired decoration (e.g EP 1 867 488 A ).

This typically involves printheads that eject ink droplets of different colors and superimpose them to produce the desired color or pattern.

However, it has been shown that known printing units require a considerable amount of space. In addition, known printing units are mostly optimized for the application of complex patterns, but not for additional functions that are required in the furniture and construction element industry, such as variable adjustment of the physical and geometric properties of the printed layer. In addition, the well-known printing units are not ideal for printing solid colors.

Other printing methods are from EP 1 935 659 A1 and the EP 2 097 265 B1 known.

Presentation of the invention

The object of the invention is to provide a device and a method for patterning a workpiece, which preferably consists at least partially of wood, wood-based materials, plastic or the like, through which a variety of geometric and physical properties of the printed layer can be achieved with a small space requirement and also an improved Printing of solid colors can be achieved.

According to the invention, this object is achieved by a device for patterning a workpiece according to claim 1 and a method for patterning a workpiece according to claim 10 . Particularly preferred developments of the invention are specified in the dependent claims.

The invention is based on the idea of providing a completely different preparation of the printing material (for example an ink) when sampling workpieces. For this purpose, the device according to the invention initially has a feed unit for feeding at least two printing components to a printing unit, and upstream of the printing unit a mixing unit for mixing the components fed by means of the feeding unit and for delivering the mixture to the printing unit.

In this way, it is possible to provide a printed layer with the desired geometric and physical properties very specifically and individually, possibly even differently for each workpiece. At the same time, the number of printing units or printheads required can be reduced, since the targeted mixing of the components means that separate printheads are no longer required for specific overlay processes. Furthermore, the device according to the invention is particularly well suited for rapid and economical printing of uni colors, since the desired uni color can already be produced upstream of the printing unit. As a result, the device according to the invention opens up completely new and diverse possibilities for the sampling of workpieces in the furniture and component industry, which preferably consist at least in sections of wood, wood-based materials, plastic or the like.

In order to enable the most targeted, precise and variable supply of the printing components to the printing unit, a development of the invention provides that the supply unit has a plurality of pumps which are connected to at least one printing component container.

Within the scope of the invention, the pressure component containers can contain and provide a wide variety of components. According to a development of the invention, it is provided that at least one pressure component container has a master liquid. By providing a stock liquid, the basis is created to a certain extent for providing a very large variety of printing materials without already being committed to a specific type of ink or a specific ink base material. Furthermore, the mother liquid can also have neutral or even cleaning properties, so that it can be used to rinse or even clean certain areas of the device if necessary.

In addition, according to a development of the invention, it is provided that at least one printing component container contains dyes, such as in particular color pigments. In this way, any colored printing material can be produced, for example in combination with a parent liquid, resulting in an extremely wide range of possible printing colors. It is particularly advantageous that setting a desired color of the printing material upstream of the printing unit also results in a particularly high-quality, but also rapid and cost-effective single-color printing.

Alternatively or additionally, according to a development of the invention, it is provided that at least one pressure component container has at least one additive, the additive preferably being selected from physically changeable additives, matting additives, foamable additives, structure-forming additives and fluorescent additives. Thanks to these additives, it is possible to give the later printed layer on the workpiece a wide variety of physical and geometric properties. For example, structured surfaces, luminous surfaces, reflective surfaces, matte surfaces, particularly thick surfaces, particularly shock-resistant surfaces and many other surfaces can be created. At the same time, this effect is achieved in a flexible and variable manner with the invention, since the desired properties can be adjusted individually for the respective workpiece depending on the supply of the additives.

Within the scope of the invention, the mixing unit can be designed in different ways. However, a particularly rapid, effective and trouble-free mixing of the printing components results when the mixing unit has at least one movable mixing element according to a development of the invention, with at least one drive for driving the movable mixing element preferably being provided.

A further increased variety of achievable properties of the later printed layer results when the mixing unit is set up according to a development of the invention to temper the supplied components, in particular to heat them. By controlling the temperature of the mixing unit, not only can the mixing of the individual components be optimized, but certain substances and properties of the printing component can also be activated or their activation behavior can be time-controlled and optimized.

In this context, according to a development of the invention, the mixing unit can also be set up so that the supplied components are only output after a dwell time. Thus, the mixing unit can also serve as an intermediate buffer, in which the components are enabled to achieve optimal mixing over time and possibly also under the influence of temperature control and/or to develop additional properties, such as a special viscosity or strength or other physical properties .

In addition, according to a development of the invention, it is provided that at least one printing unit has a secondary circuit for circulating and, if necessary, buffering a supplied printing material mixture. In this way, the operation of the mixing unit and the printing unit can be at least partially decoupled from one another, which is advantageous, for example, in the event of interruptions in the printing operation or also during dwell times on the part of the mixing unit, and minimizes the waste of printing material.

Furthermore, according to a further development of the invention, it is provided that a plurality of printing units are provided for, in particular, sequential printing, with a plurality of printing units preferably being connected to a mixing unit. By providing several printing units, special optical and physical effects can be achieved, such as the provision of multi-layer printing, multiple partial surface printing to achieve special patterns, through to a layered structure in which each layer has different properties and fulfills functions.

The advantages mentioned above can be achieved particularly effectively with a method for patterning a workpiece according to claim 10. The advantages of the invention are particularly pronounced when the surface of the workpiece to be printed is made of plastic, at least in sections. Because the printing of plastics places particularly high demands on the printing process and the printing material used, with the invention also enabling particularly high-quality and diverse printing results here.

Furthermore, according to a development of the method according to the invention, it is provided that the printing unit and/or the mixing unit are cleaned by supplying a pressure component, in particular a parent liquid, by means of the supply unit. In this way, it is possible to actually use the high flexibility and variability of the invention for changing workpieces, without a complex and separate cleaning technique being required for this.

character list

• 1 FIG. 12 schematically shows a plan view of a device for patterning a workpiece according to an embodiment of the invention.

Description of Embodiments

Preferred embodiments of the invention are described below with reference to the accompanying drawings.

A device 1 for sampling a workpiece 2 is in 1 shown schematically in a plan view.

The device 1 is used for sampling workpieces 2, as they are used in the furniture and component industry, such as furniture fronts, body parts, door leaves, etc. These are usually made of wood or wood-based materials and are often in the area of their surface 2 'Coated with a top layer, which can consist, for example, of plastic or various composite materials, but also of paper or veneer. in 1 a plate-shaped workpiece 2 is shown as an example, which is to be printed in the area of its narrow surface 2`. A so-called edge can be glued to this narrow surface, for example. However, it should be noted that the device according to the invention can also be provided for patterning a wide area or any other surface 2' of the workpiece.

As in 1 As can be seen, the device 1 in the present embodiment comprises a conveyor device 4 in the form of a continuous device, which can have, for example, a conveyor belt, a conveyor chain or other suitable conveyor elements. However, it should be noted that other conveying concepts can also be used within the scope of the present invention, for example so-called stationary machines in which the workpiece 2 is stationary and components of the device are moved in relation to the workpiece 2; mixed forms of both concepts are also within the scope of the invention possible.

For patterning the surface 2' of the workpiece, the device 1 has a printing unit 10, which in the present embodiment is designed as a drop-on-demand printing unit. Thus, the printing unit 10 pushes as indicated by an arrow 10` in 1 illustrates, drops of ink onto the surface of the workpiece 2 to be patterned. Otherwise, however, other, optionally continuous, printing methods are also possible.

Upstream of the printing unit 10, the device 1 initially comprises a feed unit 20, which has a plurality of pressure component containers 24 and 26 in the present embodiment. These pressure component containers are connected via respective pumps 22 to a mixing unit 30 whose outlet is in turn connected to the pressure unit 10 .

In the present embodiment, the printing component container 24 has a stock liquid, which can be, for example, a water-based liquid or a liquid designed for later UV curing, which is suitable for holding colorants or additives. A water-based stock liquid can also contain solvents. A stock liquid designed for later UV curing may contain an acrylate monomer mixture.

Otherwise, the stock liquid has properties that are as neutral as possible and is preferably free of dyes or pigments, so that it alone is not suitable for producing permanent print surfaces. It can therefore also be used for rinsing or cleaning the mixing unit 30 or the printing unit 10, for example.

The print component containers 26 contain different dyes, such as color pigments or additives, as required. Examples of this are physically changeable additives (e.g. polymers), matting additives (e.g. lime), foamable additives (e.g. polyurethanes), structure-forming additives (e.g. granules) or fluorescent additives.

In the present embodiment, the mixing unit has, for example, a snail-shaped mixing element 32 which is provided in a cavity within the mixing unit and can be rotated about a longitudinal axis. In the present embodiment, the mixing element 32 is connected to a rotary drive 34 and can thus be driven in rotation about its longitudinal axis. Thanks to the snail shape of the mixing element, it can be used for mixing on the one hand, but also for conveying and dispensing the supplied print components on the other. As in 1 can be seen, these are then delivered to the printing unit 10 in order to be used from there for printing the workpiece 2 .

Although in 1 not shown, the mixing unit 30 in the present embodiment has a heating unit, by means of which the supplied components can be heated. Alternatively or additionally, a cooling unit would also be conceivable. Furthermore, the mixing unit 30 can also be a be aimed at mixing the supplied components and then only delivering them to the printing unit 10 after a certain dwell time. For this purpose, on the one hand, a closure can be provided at the outlet of the mixing unit 30 or other types of mixing elements or various other measures can also be used.

As in 1 can be seen, the 1 in addition, in the area of the printing unit 10, there is a secondary circuit 12 with a secondary pump 14, which is used to circulate and, if necessary, buffer a supplied printing material mixture. This can be advantageous, for example, if no workpiece is to be printed at the moment, but the mixing unit 30 continues to supply printing material. Furthermore, the auxiliary circuit 12 can temporarily supply the printing unit 10 with printing material if the mixing unit 30 is not supplying a printing material mixture--e.g. due to a dwell time.

Although in 1 not shown, the printing device 1 can also have a plurality of printing units 10 which are arranged sequentially along the conveyor device 4 . These can all be connected to the mixing unit 30 or to at least one separate mixing unit. In any case, the arrangement of a plurality of sequential printing units enables a multi-stage and possibly also multi-layer printing of the workpiece 2, as a result of which a wide variety of physical and optical properties of the surface can be achieved.

During operation of the device 1, the stock liquid from the pressure component container 24 and one or more colorants and/or additives from the pressure component container 26 are first fed to the mixing unit 30 and mixed there by means of the mixing element 32. The printing material mixture is then output to the printing unit 10 and used for printing on the surface 2` of the workpiece.

As soon as other surface properties of the workpiece are required or if the material composition of the workpiece or the surface of the workpiece has changed, either the printing material mixture can be continuously adjusted, or the printing operation can be stopped in order to shut down both the mixing unit 30 and the printing unit 10 rinse and clean as much as possible. For this purpose, for example, stock liquid is supplied from the container 24 by means of the pump and is discharged into a collection container on the printing unit 10 . A new mixture can then be defined on the basis of the changed requirements and made available by means of the mixing unit 30 .

In order to control the functions and components mentioned, the device can have a suitable control device.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited 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.

Patent Literature Cited

• EP1867488A [0002]
• EP 1935659 A1 [0005]
• EP 2097265 B1 [0005]

Claims (12)

Device (1) for patterning a workpiece (2), which preferably consists at least partially of wood, wood-based materials, plastic or the like, comprising: at least one printing unit (10) for printing a surface (2'), in particular a narrow surface, of the workpiece (2), a conveyor device (4) for bringing about a relative movement between the workpiece (2) and the printing unit (10), and a feed unit (20) for feeding at least two printing components to the printing unit (10), wherein upstream of the printing unit (10) there is a mixing unit (30) for mixing the components supplied by means of the feed unit (20) and for delivering the mixture to the printing unit (10). device after claim 1 , in which the feed unit (20) has a plurality of pumps (22), each of which is connected to at least one pressure component container (24, 26). device after claim 2 , wherein at least one pressure component container (24) has a parent liquid. device after claim 2 or 3 , in which at least one printing component container (26) has dyes, in particular color pigments, and/or at least one additive, the additive preferably being selected from physically changeable additives, matting additives, foamable additives, structure-forming additives, fluorescent additives. Device according to one of the preceding claims, in which the mixing unit (30) has at least one movable mixing element (32), at least one drive (34) for driving the movable mixing element (32) preferably being provided. Device according to one of the preceding claims, in which the mixing unit (30) is set up to control the temperature of the supplied components, in particular to heat them. Device according to one of the preceding claims, in which the mixing unit (30) is set up to discharge the supplied components only after a dwell time. Device according to one of the preceding claims, in which at least one printing unit (10) has a secondary circuit (12) for circulating and, if necessary, buffering a supplied printing material mixture. Device according to one of the preceding claims, in which a plurality of printing units are provided for, in particular, sequential printing, with a plurality of printing units preferably being connected to a mixing unit. Method for patterning a workpiece (2), which preferably consists at least partially of wood, wood materials, plastic or the like, using a device (1) according to one of the preceding claims, with the steps: bringing about a relative movement between the workpiece (2) and the printing unit (10) by means of the conveyor device (4), mixing components supplied by means of the supply unit (20) in the mixing unit (30) and delivering the mixture to the printing unit (10), and Printing a surface (2`), in particular a narrow surface, of the workpiece (2) by means of the printing unit (10). procedure after claim 10 , in which the surface (2') of the workpiece (2) to be printed consists at least in sections of plastic. procedure after claim 10 or 11 , in which the printing unit (10) and/or the mixing unit (30) are cleaned in that a printing component, in particular a parent liquid, is supplied by means of the supply unit (20).

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