METHOD AND APPARATUS FOR COATING A NARROW SIDE OF A PLATE-SHAPED WORKPIECE

Abstract

The invention relates to a method for coating a narrow side (1) of a plate-shaped workpiece (2) with a coating material (3), in particular a strip-shaped or band-shaped coating material (3), using a coating apparatus, wherein, before being applied to the narrow side (1) of the workpiece (2), the coating material (3) is colored with a basic color (4) at least in a peripheral area (5), which is assigned to an adhesive surface (6) of the coating material (3), or the coating material (3) is entirely colored with the basic color (4), wherein the basic color (4) is color-matched to a shade and/or pattern and/or decoration of a surface (8) of the workpiece (2) such that, after the coating material (3) has been applied to the narrow side (1) of the workpiece (2), a matched color transition between the colored coating material (3) and the shade and/or pattern and/or decoration of the surface (8) of the workpiece (2) is formed, and to a coating apparatus carrying out such a method.

Claims

1. Method for coating a narrow side (1) of a plate-shaped workpiece (2) with a coating material (3), in particular a strip-shaped or band-shaped coating material (3), using a coating apparatus, characterized in that before being applied to the narrow side (1) of the workpiece (2), the coating material (3) is colored with a basic color (4) at least in a peripheral area (5), which is assigned to an adhesive surface (6) of the coating material (3), or the coating material (3) is entirely colored with the basic color (4), wherein the basic color (4) is color-matched to a shade and/or pattern and/or decoration of a surface (8) of the workpiece (2) such that, after the coating material (3) has been applied to the narrow side (1) of the workpiece (2), a homogeneous color transition between the colored coating material (3) and the shade and/or pattern and/or decoration of the surface (8) of the workpiece (2) is formed.

2. Method according to claim 1, characterized in that before being fed to the coating apparatus, the coating material (3) is colored with the basic color (4) or the coating material (3) is colored with the basic color (4) by a coloring device of the coating apparatus.

3. Method according to claim 1, characterized in that the coating apparatus is provided with a plurality of coating materials (3) colored with different basic colors (4), wherein one of the coating materials (3) whose basic color (4) is color-matched to the shade and/or pattern and/or decoration of the surface (8) of the workpiece (2) is fed to the coating apparatus for coating the narrow side (1) of the workpiece (2).

4. Method according to claim 1, characterized in that after application to the narrow side (1) of the workpiece (2), the coating material (3), in particular a narrow surface (10) opposite the adhesive surface (6) and extending along the coating material (3) and/or at least one transition area (11) of the coating material (3) extending along the narrow surface (10), is printed with a printing device (13) having at least one printing stage.

5. Method according to claim 4, characterized in that the coating material (3) is printed inline in the coating device with the printing device (13) and an active drying process of the printing dyes (12) applied to the coating material (3) occurs preferably after each printing stage.

6. Method according to claim 1, characterized in that the shade and/or pattern and/or decoration of the surface (8) of the workpiece (2) is detected by a sensor device, and a coating material (3) with a color-matched basic color (4) is automatically fed to the coating apparatus based on the detected shade and/or pattern and/or decoration, and/or the printing device (13) is controlled by the sensor device such that the coating material (3) is printed with a pattern and/or decoration which is matched to the detected shade and/or pattern and/or decoration.

7. Coating apparatus for coating a narrow side (1) of a plate-shaped workpiece (2) with a coating material (3), in particular a strip-shaped or band-shaped coating material (3), using a feeding device for feeding the coating material (3) to the narrow side (1) of the workpiece (2) and a coating unit for applying the coating material (3) to the narrow side (1) of the workpiece (2), characterized in that the coating apparatus carries out the method according to claim 1.

Description

[0014] The invention and further advantageous embodiments and further developments thereof will be described and explained in more detail below on the basis of the examples shown in the drawings. The features that are apparent from the description and the drawings can be applied individually or jointly in any combination in accordance with the invention. The drawings show the following:

[0015] FIG. 1 shows a flow chart of a method for coating a narrow side of a workpiece with a coating material,

[0016] FIG. 2 shows a sectional view of a workpiece coated with the coating material,

[0017] FIG. 3 shows a sectional view of an alternative embodiment of a workpiece coated with the coating material,

[0018] FIG. 4 shows a schematic representation of the coated workpiece during a printing process, and

[0019] FIG. 5 shows an exemplary representation of the printed coating material in various printing stages of the printing method.

[0020] FIG. 1 shows a flow chart of a method for coating a narrow side 1 of a plate-shaped workpiece 2 with a coating material 3. In particular, the narrow side 1 of the workpiece 2 is coated with a strip-shaped or band-shaped coating material 3. Preferably, the coating material 3 is an edge material formed, for example, of a plastic material, wood material or a composite material. The workpiece 2 consists in particular of a wood material, for example a chipboard material.

[0021] In a first method step, the plate-shaped workpiece 2 is first brought to a predetermined format, in particular cut or sawed, in a coating apparatus not shown in detail. It can also be provided that a workpiece 2, which has previously been brought to a predetermined format, is fed to the coating apparatus.

[0022] Then the coating material 3 is applied to the narrow side 1 of the workpiece 2, wherein a permanent bond between the coating material 3 and the workpiece 2 is formed preferably by an adhesive. Various coating apparatuses and methods are already known for applying the coating material 3 to the workpiece 2. For instance, DE 10 2015 206 010 A1 describes a coating apparatus and a method, by means of which a high-quality coating of the narrow side of the workpiece is made possible.

[0023] In the method according to the invention, a coating material 3, which was previously colored with a basic color 4, is fed to the coating apparatus for application to the narrow side 1 of the workpiece 2. The coating material 3 can be entirely colored with the basic color 4, as schematically shown in FIG. 2. Colored means that the basic color 4 is not only applied to the surface of the coating material 3, but that the body of the coating material 3 is at least partially penetrated or colored through by the basic color 4. Likewise, it may be provided that the coating material 3 is colored only in a peripheral area 5 provided adjacent to an adhesive surface 6 of the coating material 3. In particular, side areas 7 of the coating material 3—which are in the visible area when the coating material 3 is applied to the narrow side 1—as a result have the basic color 4. This coloring of the peripheral area 5 is shown in FIG. 3.

[0024] The basic color 4 is matched to a shade and/or pattern or decoration of a surface 8 of the workpiece 2. After the coating material 3 has been applied to the narrow side 1 of the workpiece 2, a visually imperceptible or only minimally perceptible color change can thus be formed between the shade and/or pattern and/or decoration of the surface 8 of the workpiece 2 and the basic color 4 of the colored coating material 3, in particular the colored side areas 7 of the coating material 3.

[0025] The coating apparatus can be provided with a plurality of coating materials 3 that are colored with different basic colors 4. The basic colors 4 can each be matched, for example, to different shades and/or patterns and/or decorations of workpieces 2 that are processed in the coating apparatus. It may be provided that a coating material 3 having a basic color 4 is used for several shades and/or patterns and/or decorations of the surface 8 of the workpieces 2, which are similar in color or differ only slightly. In this way, a small number of different coating materials 3 with different basic colors 4 can be provided, for example ten different basic colors 4, which can be applied to a plurality of workpieces 2 with different shades and/or patterns and/or decorations. As a result, reduced storage of coating materials 3 can be achieved.

[0026] If the coating apparatus is configured to process several coating materials 3, an automated feeding device can be provided which automatically feeds the corresponding coating material 3 to the coating apparatus depending on the shade and/or pattern and/or decoration of the workpiece 2. For example, the coating apparatus may have an optical sensor unit. This detects a shade and/or a pattern and/or decoration of the workpiece 2, so that on the basis of the detected color signal an automated selection is made from the provided coating materials 3 with the suitable basic color 4 and the corresponding coating material 3 is fed to the coating apparatus.

[0027] After the coating material 3 has been applied to the narrow side 1 of the workpiece 2, an additional processing or finishing step may be provided in a further method step to form a high-quality coating of the narrow side 1 of the workpiece 2.

[0028] In a subsequent method step, the coating material 3 is printed, as shown schematically in FIG. 4. Printing with one or more printing dyes 12 is carried out in particular on a narrow surface 10, which is opposite the adhesive surface 6 of the coating material 3, and on a transition area 11 extending along the narrow surface 10, which merges into one of the side areas 7 of the coating material 3. The transition area 11 can be rounded or chamfered, for example. In particular, a transition area 11 may be provided along both sides of the narrow surface 10.

[0029] Before the coating material 3 is printed, pretreatment of the coating material 3, in particular the narrow surface 10 and transition areas 11 to be printed, can occur. This pretreatment may include, for example, cleaning and/or priming, for example applying a primer, of the coating material 3. This allows a durable and visually high-quality dye application to be achieved.

[0030] In a further method step, printing of the coating material 3 is carried out by a printing device 13 shown schematically in FIG. 4. The printing device 13 may have a plurality of printing stages, each printing stage comprising a plurality of printing dyes 12. For example, the printing dyes 12 cyan, magenta, yellow and a black component can be provided in each printing stage. Other color gradations, for example light shades, and/or a white printing dye 12 can also be provided. The printing device 13 can either be provided as a separate unit downstream of the coating apparatus or as part of the coating apparatus. This means that printing can take place “inline” in the coating process.

[0031] FIG. 5 shows three exemplary illustrations of different printing stages of a printing process on the basis of a fully colored coating material 3. The illustrations each show a top view of the narrow surface 10 of the coating material 3. Before printing, the coating material 3 has the basic color 4 with which the coating material 3 is colored. In the first printing stage, the coating material 3, in particular the narrow surface 10 and, if applicable, the transition areas 11 adjacent to the narrow surface 10, is printed with a first printing dye 12 in several individual printing areas 14. Preferably, the coating material 3 is first printed with the white printing dye 12. If necessary, a different opacity of the printing dye 12 can be provided in the individual areas. This allows different shades or gradations of color to be achieved. Within the first printing stage, this printing process can be repeated with the further printing dyes 12. Advantageously, printing is carried out in several steps, with lighter printing dyes 12 being printed first and progressively darker printing dyes 12 being printed in each of the subsequent steps. Printing with the individual printing dyes 12 in one printing stage can be carried out both step by step, i.e. one after the other, and simultaneously. It may be provided that the various printing dyes 12 at least partially overlap in the printing areas 14.

[0032] In the subsequent printing stages, this printing process can be repeated with the respective printing dyes 12, preferably with printing dyes 12 becoming darker in each printing stage. This provides a multi-layer dye application on the coating material 3. In this way, the coating material 3 can be printed with any pattern and/or decoration, for example a representation of a wood structure. An example of such a wood decoration is shown in the lowest illustration according to FIG. 5. The wood decoration printed on the coating material 3 corresponds in particular to a wood decoration which the surface 8 of the workpiece 2 also has.

[0033] Within a printing stage and/or between the individual printing stages, an active drying process can also be provided. This enables rapid drying of the printed printing dyes 12.

[0034] After printing, the coating material 3 is varnished, at least the narrow surface 10 and/or peripheral areas 11 that are printed with printing dye 12 are varnished. One or more layers of varnish are applied to the coating material 3. The varnish layer or layers can be applied, for example, by a printing process. It may also be provided that the varnishing creates a structured surface. Insofar as the coating material 3 is printed with the representation of a wood structure (cf. FIG. 5), both a visual appearance and a haptic impression of a natural wood surface can be reinforced or created by such a structured varnishing. The varnishing can be followed by another active drying process.

[0035] As shown in FIG. 4, the printing device 13 or a print jet 15 of the printing device 13 is advantageously aligned perpendicular to the narrow side 1 of the workpiece 2. Thus, the dye is applied in particular to the narrow surface 10 and the adjacent transition areas 11 of the coating material 3. Since the side areas 7 are arranged parallel to the printing device 13 or the print jet 15, no printing with the printing dyes 12 takes place on the side areas 7. The unprinted side areas 7 of the coating material 3 as a result have the basic color 4 also after the narrow surface 10 and the transition areas 11 have been printed. Since this basic color 4 is color-matched to the shade of the pattern and/or decoration printed on the coating material 3 and/or the surface 8 of the workpiece 2, no color difference or only a slight color difference can be perceived between the coating material 3 and the surface 8 of the workpiece 2. Thus, the method forms a visually smooth or seamless color transition from the coating material 3 to the surface 8 of the workpiece 2. This conveys the visual impression that the workpiece 2 is formed from a uniform material, e.g. solid wood. Full printing of the coating material 3 by the printing device 13, i.e. of the narrow surface 10, the transition areas 11 as well as the side areas 7, is therefore not necessary in this coating method. An additional multi-axis adjustment mechanism for the printing device 13 can thus be omitted.

LIST OF REFERENCE NUMBERS

[0036] 1. Narrow side [0037] 2. Workpiece [0038] 3. Coating material [0039] 4. Basic color [0040] 5. Peripheral area [0041] 6. Adhesive surface [0042] 7. Side area [0043] 8. Surface [0044] 10. Narrow surface [0045] 11. Transition area [0046] 12. Printing dye [0047] 13. Printing device [0048] 14. Printing area [0049] 15. Print jet