AU705402B2

AU705402B2 - Process for printing an article, and floor covering obtainable thereby

Info

Publication number: AU705402B2
Application number: AU61876/96A
Authority: AU
Inventors: Erhard Lorch
Original assignee: DLW AG
Current assignee: DLW AG
Priority date: 1995-06-26
Filing date: 1996-06-26
Publication date: 1999-05-20
Anticipated expiration: 2016-06-26
Also published as: JP2000500078A; ATE185325T1; HUP9802870A3; PL324037A1; EP0835184B1; DE59603290D1; DK0835184T3; AU6187696A; WO1997001445A1; EP0835184A1; HUP9802870A2; DE19523188C2; CA2227730A1; ES2140104T3; DE19523188A1

Abstract

A process is proposed for printing an object using chromatic components from a three- or four-colour set of a printing pattern. The neutral parts of the chromatic components of the three-colour set are reduced to produce a neutral component and correspondingly modified chromatic components. The object is printed using the modified chromatic components and a special colour based on the neutral component.

Description

TRANSLATION

from: during proof matching, all three or four color separations have to be altered, since a desired alteration to the result is as a rule not achievable by altering only one color separation. In addition, a large number of items of data have to be stored in order to make later reprints possible.

Added to this is the further problem that, precisely in the field of floor coverings, it is often desirable to obtain from one design a plurality of different colorations in the sense of a series of colors, which ideally can further be combined with one another. Of course, these requirements potentially lead to the problems cited at the beginning in the setting-up of the color separation. This is because each color separation in the special color space is selected in accordance with the optical color impressions and is worked on until there is the closest possible approximation to the draft design. In this case, the special colors must be exchangeable in relation to the respective color separations (setting up a series of colors), and a register difference induced by the operation and the material must be possible (for example if a 400 cm wide product web wanders longitudinally and laterally in an uncontrolled manner because of material distortion, thickness differences, etc.). As a result of the fact that the special colors are separated empirically, the result in the superimposed print is often LAWYERS' AND MERCHANTS' TRANSLATION BUREAU INC.

Legal, Financial, Scientific, Technical and Patent Translations 12) 344-2930/2931 11 BROADWAY, NEW YORK, NY 10004 Fax: (212) 422-6877 Itant Founded in 1903 by V. BERTSCHE, CH.E., A.C.S. CARL V. BERTSCHE

TRANSLATION

from: unpredictable superimpositions in the surface, which lead to images in the surface.

A further production problem which arises is that, in the case of each colour setting, as a rule all the individual colors of the respective printing units have to be changed.

In this case, given a product width of 400 cm, for each inking unit at least fifty kilograms of residual ink are produced, which have to be emptied and stored for further processing.

Against this background, the problem on which the invention is based is that of specifying a simpler process for printing articles.

This problem is solved by means of a process for printing an article in accordance with claim 1.

Using the process according to the invention, the entire process, from working on the repro recordings to setting up the series of colors, is substantially simplified. For the reduction of the neutral components of the color separations of the three-color set, producing a neutral separation, recourse can be made to known processes. For example, it is known from offset printing to reduce the colored inks in LAWYERS' AND MERCHANTS' TRANSLATION BUREAU INC.

L' Legal, Financial, Scientific, Technical and Patent Translations (212) 344-2930/2931 11 BROADWAY, NEW YORK, NY 10004 Fax: (212) 422-6877 O sultant Founded in 1903 by WM. BERTSCHE, CH.E., A.C.S. CARL V. BERTSCHE

TRANSLATION

-4from: terms of the three-color depths (secondary color reduction) in order to achieve a saving in ink and hence more rapid running of the machine. In the case of the invention, preference is given to the so-called polychromatic color reduction (PCR), in which the neutral components in the color separations are replaced by a black separation. In other words, all the gray values from light to dark are built up not by means of complementary color addition but exclusively using the black printing ink.

This process, known per se, is now preferably used in the invention in order to print the article to be printed using a special color. Within the context of the present invention, special colors are in this case in general understood as all colors and color mixtures excluding the three colors of the three-color set from the printing original. In this case, firstly a three-color or four-color set is set up from the repro picture (printing original), which preferably has the color separations of the primary colors, magenta, cyan and yellow. This has the advantage, in particular, that the color management is considerably simplified on the basis of standardized color spaces CIELAB), in particular when using digital technology.

LAWYERS' AND MERCHANTS' TRANSLATION BUREAU INC.

Legal, Financial, Scientific, Technical and Patent Translations -7 o (212) 344-2930/2931 11 BROADWAY, NEW YORK, NY 10004 Fax: (212) 422-6877 onsultant Founded in 1903 by WM. BERTSCHE, CH.E., A.C.S. CARL V. BERTSCHE

TRANSLATION

from. Since it is possible to operate with the same primary colors, with the exception of the one special color to be printed on the basis of the neutral separation, it is generally possible, by means of suitable proofing processes (for example by means of a high-resolution ink-jet printer), to set up data sets ready for engraving a cylinder, even without greater knowledge of the technical boundary conditions of gravure printing. It has further been shown that, by varying only the one special color, any desired series of colors can be set up on the basis of the same design, and match one another.

For later reprints, storage of the appropriate printing data, which requires a relatively small outlay on storage, is possible.

The neutral separation preferably results from the sum of the differences between the original and the altered color separations of the three-color set. This is implemented, for example, using polychromatic color reduction (PCR, see above).

Furthermore, it has been shown that the best results are achieved if, in order to produce the neutral separation, the original color separations are altered in such a way that the LAWYERS' AND MERCHANTS' TRANSLATION BUREAU INC.

Legal, Financial, Scientific, Technical and Patent Translations 344-2930/2931 11 BROADWAY, NEW YORK, NY 10004 Fax: (212) 422-6877 sultant Founded in 1903 by WM. BERTSCHE, CH.E., A.C.S. CARL V. BERTSCHE

TRANSLATION

from.: -6maximum possible area coverage reduction is established.

The article to be printed is preferably printed not only on the basis of the neutral separation and the altered color separations, but in addition on the basis of a skeleton black separation, which is produced by the neutral separation being attenuated. The skeleton black produces the "drawing" and thus generates the impression of a greater "depth".

The skeleton black separation is preferably attenuated by to 90% with respect to the neutral separation, with the result that the article to be printed is printed with 50% to of the deepest black. Particularly preferred is an attenuation by 70 to 85% of the neutral separation, with the result that the article to be printed is printed with 30 to percent of the deepest black.

Furthermore, it has been shown that the overall impression can be improved still further if the skeleton black separation is made sharper. Sharpening is to be understood in this context as the masking out of the gray values that are present. Ideally, the skeleton black separation is made sharper to the maximum, with the result that this separation exhibits only black and while components.

SLAWYERS' AND MERCHANTS' TRANSLATION BUREAU INC.

Legal, Financial, Scientific, Technical and Patent Translations Tel (212) 344-2930/2931 11 BROADWAY, NEW YORK, NY 10004 Fax: (212) 422-6877 /sultant Founded in 1903 by '4 BERTSCHE, CH.E., A.C.S. CARL V. BERTSCHE

TRANSLATION

from: Finally, it has been shown that, in order to adapt the primary colors (of the three colors of the three-color set) to the actual printing conditions, the saturation of the altered color separations is adapted for the respective printing operation. In this way, ideal fixing of the middle tone in relation to depth and light can be achieved.

For the reduction of register problems (color shifts), the altered color separations are advantageously made less sharp.

The invention is described below using an exemplary embodiment with reference to the single figure.

In order to set up data sets ready for engraving a cylinder for the printing of plastic floorcoverings using gravure printing, the procedure according to one embodiment of the invention is as follows.

The starting point is a digital four-color set C 1

M

1 YK from a printing original, which is defined within the context of a standard color space CIELAB). This digital four-color set, comprising one separation in each case for cyan, magenta, yellow and black, can be obtained in the most diverse ways. On the one hand, the four-color set can be obtained by means of digital recording of an artificial draft

RA

LAWYERS' AND MERCHANTS' TRANSLATION BUREAU INC.

,1 Legal, Financial, Scientific. Technical and Patent Translations 12) 344-2930/2931 11 BROADWAY. NEW YORK, NY 10004 Fax: (212) 422-6877 sultant Founded in 1903 by M. BERTSCHE, CH.E., A.C.S. CARL V. BERTSCHE

TRANSLATION

-8from: or a natural original (for example a marble slab). The widest possible range of manipulations, such as positioning, retouching, setting up repeats, etc. can be performed on this digital recording by means of electronic image processing.

The data manipulated in this way are then converted into the CIELAB color space, obtaining the color separations CMYK.

Alternatively, a design can also be generated directly on the computer, without reproduction, and finally converted into the CIELAB color space. Examples of a fourcolor set CMYK obtained in this way in the CIELAB color space are illustrated on the left-hand side of the figure.

Next, an algorithm for the polychromatic color reduction (PCR) is applied to the color separations CjM 1 Yj of the four-color set, in which algorithm the neutral parts of the individual color separations (if appropriate, also only one color separation, in the event that the other color separations do not contain any neutral components) are "extracted" and combined into a neutral separation K2. The neutral separation K2 thus represents the sum of the differences between the original color separations CM 1 Yl and the altered color separations CM 2

Y

2 The neutral separation K2 is then attenuated, producing a skeleton black separation Kl. Finally, the color separations -0 L! LAWYERS' AND MERCHANTS' TRANSLATION BUREAU INC.

Legal, Financial, Scientific, Technical and Patent Translations 12) 344-2930/2931 11 BROADWAY, NEW YORK. NY 10004 Fax: (212) 422-6877 nsultant Founded in 1903 by WM. BERTSCHE, CH.E., A.C.S. CARL V. BERTSCHE

TRANSLATION

from:

C

2

M

2

Y

2 are made much less sharp, and the neutral separation K2 and the skeleton black separation K1 are made sharper.

The separation C 2

M

2 YKIK2 obtained in this way are illustrated on the right-hand side of the figure.

The proof adaptation is then performed by means of a suitable proofing machine, for example an ink-jet printer (IRIS).

Proofing is performed for the separations C 2

M

2

Y

2 and K1 using the colors cyan, magenta, yellow and black; for the separation K2, a special color which leads to the best possible reduction of the design originally aimed at is ascertained empirically.

Thus, by means of the variation of only one special color, a desired design can easily be ascertained. The data sets obtained in this way can be stored in defined formats (e.g.

TIFF) and subsequently used as the basis for the widest range of printing processes, such as gravure printing, offset printing but also for direct printing (digital printing).

In order to set up series of colors, that is to say a series of designs on the basis of the same basic design, but having different colorations ("colorits"), the procedure is precisely the same as during the proof adaptation in order to LAWYERS' AND MERCHANTS' TRANSLATION BUREAU INC.

Legal, Financial, Scientific, Technical and Patent Translations -12) 344-2930/2931 11 BROADWAY, NEW YORK, NY 10004 Fax: (212) 422-6877 onsultant Founded in 1903 by WM. BERTSCHE, CH.E., A.C.S. CARL V. BERTSCHE

TRANSLATION

from.: ascertain the ideal reproduction. The special color that is suitable for the respective coloration is ascertained empirically. The setting-up of a series of colors with various colorations, which "match one another", is extremely simple by virtue of altering only one parameter (the special color). The storage of the necessary data for any reprint is also possible with a low outlay on storage (cf. above).

It should further be mentioned that, during the proof adaptation in order to ascertain the ideal reproduction, and also to ascertain the "colorits", the color separations C 2

M

2

Y

2 that have been altered on the basis of the neutral component reduction can be altered in terms of their saturation, in order to be able to undertake adaptations to the actual printing conditions.

The data sets ascertained in this way (the respectively digitally stored color separations C 2

M

2

Y

2 K1K2 and the respectively defined special color) are data sets "ready for engraving", that is to say that it is possible to use these data sets directly for the engraving of gravure printing cylinders for the printing of plastic floor covering webs. It goes without saying that it is also possible to use these data sets for other printing processes, in particular for the direct printing (digital printing) which will gain in significance in the future.

LAWYERS' AND MERCHANTS' TRANSLATION BUREAU INC.

Legal, Financial, Scientific, Technical and Patent Translations T o el: (212) 344-2930/2931 11 BROADWAY, NEW YORK, NY 10004 Fax: (212)422-6877 Consultant Founded in 1903 by WM. BERTSCHE, CH.E., A.C.S. CARL V. BERTSCHE 11 THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1 A process for printing an article in accordance with color separations

(C

1

M

1

Y

1 of a three-color or four-color set from a printing original, having the steps: reducing the neutral components of the color separations

(C

1 MiY) of the color set, whilst producing a neutral separation (K2) and correspondingly altered color separations

(C

2

M

2

Y

2 printing the article to be printed on the basis of the altered color separations

(C

2

M

2

Y

2 and printing the article to be printed, using a special color different from black, on the basis of the neutral separation (K2).

2 The process as claimed in claim 1, wherein the neutral separation (K2) represents the sum of the differences between the original (C 1

M

i

Y

1 and the altered (C 2

M

2

Y

2 color separations of the three-color set.

3 The process as claimed in claim 1 or 2, wherein, in order to produce the neutral separation the original color separations (CiM 1

Y

1 are altered in such a way that the maximum possible area coverage reduction is established.

.*S

4 The process as claimed in any one of claims 1 to 3, wherein the neutral separation (K2) is attenuated, producing a skeleton black separation (K1), and the article to be printed is printed using black on the basis of the skeleton black separation (K1).

5 The process as claimed in claim 4, wherein the skeleton black separation (K1) is attenuated by 50% 90% with respect to the neutral separation (K2), *with the result that the article to be printed is printed with 50% 10% of the deepest black.