Patent ID: 12246555

DESCRIPTION OF THE INVENTION

FIG.1shows an example of a process according to the invention in a flow chart. First, a first component with a first decor is provided, wherein the first decor is applied to the first component, for example, by direct printing or via a printed decor paper. The first component is to be combined with a second component, wherein the colour change of the decor combination is coordinated.

In action2, colour measurements are carried out under at least two different illuminants on the first decor of the first component. For this purpose, for example, at least one colour measurement is carried out at each measuring point of the first decor under the standard illuminants D65, A and F11. A hyperspectral colour measurement is used here.

The first decor is a multi-coloured or discontinuous decor. In order to obtain representative colour measurement values for the first decor, the colour measurements are carried out under at least two different illuminants on several (spatially spaced) sections of the first decor. On the first decor, measurement points are distributed over a grid with a measurement length of 220 mm, using a resolution of at least 100 dpi and in particular at least 200 dpi. The procedure can also be carried out for plain decors.

When the illuminant is changed, a colour shift of the first decor typically occurs. For this purpose,FIG.2schematically shows colour measurement values at a single measuring point of the first decor under different illuminants. The colour measurement values are expressed as colour channels in the CIELAB colour space, wherein the colour measurement is based on a CIE-1964 standard observer. As an example,FIG.2shows the colour channels L* (luminance), C* (chromaticity) and hab(chromaticity angle) and their dependence on the illuminant.

For each measured section of the first decor, colour measurement values for the colour channels can be obtained depending on the illuminant and measurement curves analogous toFIG.2. In action4fromFIG.1, colour measurement values of the colour measurements from several sections of the first decor are grouped. Here, similar colour measurement values are grouped to each other, wherein in particular a colour distance such as at least one of E, L*, a*, b* and/or habof the colour measurement values is used as a criterion for the grouping.

Based on the colour measurement values, a reference colour change of the first decor under the change between the at least two different illuminants is determined in action6. For this purpose, the grouped colour measurement values from action4are subjected to a statistical evaluation. In one embodiment, the colour changes of the sections are averaged to obtain an averaged colour change as a reference colour change. Alternatively, for the grouped colourimetric values or for the sections of the first decor whose colourimetric values are each assigned to a group of colourimetric values, a selection and/or compilation of inks is made in each case, as described below.

Printing of the second decoration on the second component is carried out by digital printing and can also be carried out by direct printing and/or by printing on a decorative paper. Printing is performed with the predetermined ink types for C, M, Y and K, wherein at least one further ink type selected from C″, M″, Y″ and K″ is provided. The further ink types C″, M″, Y″ and/or K″ have a different colour change to the respective corresponding predefined ink type C, M, Y and K. The colour change is determined by the ink type. For the individual ink types, for example, measurement curves similar to those shown inFIG.2are known in advance or are determined during the process, wherein an expected colour change of the second decoration to be printed can be modelled on the basis of these colour measurement values for the ink types.

For printing the second decoration, it is determined whether the predetermined ink type, the corresponding other ink type or a mixture of these ink types is used to match the colour change of the second decoration to the reference colour change. For example, in action8, the ink types Y and Y″ are selected or the ink types are mixed in a ratio depending on which of the two yellow tones Y and Y″ can replicate the reference colour change as closely as possible in a print of the second decoration.

The at least two different types of ink are mixed in separate containers and, for example, before printing and applied via a single print head in action10. Alternatively, one print head is provided for each of the at least two different ink types, allowing the ink types to be printed independently of each other. In this case, the quantity ratios and/or the printed pixel size of the respective ink type can be varied in such a way that the colour change of the second decoration is aligned with the reference colour change.

FIG.3further shows a schematic representation of a decor combination with a first component12and a second component14for furniture parts and/or interior fittings. The first component12comprises a plate-shaped material which is formed, for example, by a wood-based material board such as a chipboard or fiberboard. The first component12has a first decoration16in the form of a decorative layer which is formed, for example, by coating with a printed decorative paper or by direct printing on the visible surface of the first component12.

A second component14comprising an edge profile for the plate-shaped material of the first component12is arranged on the narrow side of the first component12. The second component14has a second decoration18printed on a visible surface by the method described, which together with the first decoration16forms a decoration combination. With the method according to the invention, it is possible to easily match or coordinate the colour changes of the first decoration16and the second decoration18. A control device20adapted to perform a determination of a reference colour change of the first decoration under the change between the at least two different illuminants is shown.