EP2295248A1 - Method and device for finding the specific ink transfer behaviour of a ink transfer roller - Google Patents

Abstract

The method involves comparing the test data with the data for color transporting properties of a color transporting roller by a control unit, and applying the data as data for the color transport of the arbitrary roller. The extrapolation data is represented as a standardization function, which is also a scaling factor. An independent claim is also included for a device for determining specific color transporting properties of a color transporting roller for a printing ink.

Description

The invention relates to an apparatus and a method for determining the specific color transport behavior of a color-transporting roller for a printing ink, which has a certain pigment composition.

Methods of the generic type are known. The knowledge of the color transport behavior of a color-transporting roller is of great interest in order to be able to select the right rollers for a print job and to actually achieve the desired print result with the rollers once selected. In many printing processes, ink is transported by one or more ink-transporting rollers before the ink reaches the substrate. The ink rollers include smooth rollers and especially anilox rollers.

The printing inks usually consist of a mixture or a solution of color-active substances, waste and solvents. Cuttings here are a liquid component of the color without color pigments. The addition of waste to the color pigments thus changes the color impression of the printed image, but not the viscosity. If, however, solvents are added to the color pigments and the blend, both the color impression of the print image (since the proportion of color pigments decreases overall) and the viscosity of the color change.

The ink transport adhesion of different inking rollers is different with respect to the different color components, so that the selection of the rollers has a significant influence on the color impression that the viewer has perceived. Thus, different rollers take on different color volumes and transfer these color components in different ways again to the substrate or other rolls and machine components. The latter process is often referred to by the term color split.

The physical reason for this different behavior of the rollers lies in their differently shaped surfaces, which have different adhesion properties. A significant influence - especially with anilox rollers - also has the surface structure. Among other things, for this reason, the rollers may change their color transporting properties during their lifetime due to wear.

Since it comes in a print job to cause a certain color impression with certain inks, not inconsiderable effort is operated for determining the Farbtransportvefialtens a color-transporting roller and the subsequent adjustment of the printed image.

For every basic color of a color series or a color assortment and for the different substrates, the common types of rolls must be tested. It should be noted that even printers who set when selecting rolls, for example, on a manufacturer, different types of ink rollers require. For example, with the use of anilox rolls in printing shops, it is customary to stockpile and also use anilox rolls with at least three distinctly different volumes. Only in this way can print images that require a different inking be printed with high quality.

Transport properties of an inking roller are determined by determining the layer thickness of the ink application on the substrate. The application of paint or the layer thickness can be characterized by a density measurement - which is carried out with a densitometer - in the absorption range of the remission spectrum of the ink. The densitometer is used to determine a value for the color density. The color density is proportional to the layer thickness of the paint applied to the substrate, so that from the Color density value, the layer thickness of the color can be calculated or calculated. Alternatively, the reflectance spectrum of the color can be detected with a spectrophotometer. From the reflectance spectrum, the density or extinction spectrum, which characterizes the spectral absorbance, can be determined with a color model. In order to be able to calculate a color recipe for a particular color value, a so-called blend series must be created. Such a blend series comprises measurements of the spectral intensity of the light reflected from a printed image at a plurality of blend concentrations of a printing ink. In this context, the characteristic element of a printing ink is the color pigments contained in the printing ink and, if appropriate, in the case of several pigment types, their mixing ratio with one another.

Such a series of cuts could be recorded by successively printing a printing machine of a differently diluted color using the roller to be tested and measuring the printed images accordingly.

In order to reduce the associated machine downtime and Druckmiftelverbrauch, you print in the rule, however, with the press for testing purposes initially only with a waste concentration.

The printed image produced in this way is compared with a printed image printed in a test stand (test printing unit) with the same color and combination of blanks. The test stand or the test printing unit is often referred to by the expert as a proofing device.

In the test stand is printed with a gravure cylinder having areas with different surface engravings. The area which has the printing image which is the most similar to the machine pressure serves as a pattern for the surface of a new gravure cylinder. With this new gravure cylinder color is then transferred in the test stand with different waste concentrations on the substrate and thus determines the Verschnittreihe. This blend series is the basis for a so-called color assortment, which is needed for recipe calculation with a color recipe software. A color assortment consists of a series of blanks for each primary color on a particular substrate.

Alternative test stands are also known in which a printing material is unrolled over a stationary gravure printing plate. All of these test stands and sample printing devices are referred to for the purposes of this document as a test printing unit, since their function as in a printing or inking unit is just printing on substrate.

Against the background and in knowledge of the waste series recorded as described above, the color pigment, blend and solvent concentration for the printing ink is now determined, with which the actual printing process is to be carried out. From the above description it is clear that the described process of determining the Verschnittreihe is very complex even when using the test stand. If the printer determines after printing that the printed image does not live up to its expectations, it has the option of modifying print parameters and "trying" settings that better meet their expectations. Even the latter process, which produces print image changes and thus waste during the actual printing process, is laborious.

Therefore, the object of the present invention is to facilitate the cost of the entire process from the test of the color transport properties of the roller to achieve the desired color impression in the actual printing process and thus to reduce the cost of this process. The object is achieved by the method claim 1 and the device claim 15.

Here, the method according to the invention proceeds from the above-described method for determining the specific ink transport behavior of a ink-transporting roller for a printing ink which has a certain pigment composition.

In these methods, the roller to be tested is used in a printing unit and printing substrate printed with ink of this pigment composition. The printing unit can be a complete printing unit of the printing press and / or to be a test stand. It is important that a printed image can be produced there using the roller to be tested under similar conditions as in the printing press.

The pressure is carried out at least with a number N of mixing ratios of the pigment composition to waste. As a rule, one or two mixing ratios are sufficient for the roller to be tested. At least a part of the printed image, which is produced using the roller to be tested, is examined in an optical measuring device. The part of the printed image can be a partial area or the whole area. Examining brands in addition to the actual print motif is also possible here. The measurement should be performed in an area containing the solid surface of the color mixture.

The optical measuring device obtains by their measurements data that - as they were obtained using the roller to be tested - are called test data in the present context.

The known method is further developed in that a control device compares the test data with data on the color transport behavior of an arbitrary roller. The arbitrary roller is usually another ink-transporting roller, which may have a different surface texture or different inking volume compared to the roller to be tested.

As data for color transport of the arbitrary roller data are used, which were carried out on the basis of the pressure with at least a number M of mixing ratios of the color to waste, which is greater than the number N. This ensures that the data for color transport of the arbitrary roll allow statements to more mixing ratios of the particular pigment composition than the N measurements with the roller to be tested. As a rule, one or two measurements on the ink transport behavior of the roller to be tested (with different proportion of waste in the color) are compared with measurements for a complete blend series to the arbitrary roll (often measurements at eight to twelve color blend concentrations). Here, the measurements of the blend series with the methods of the prior art or by the Extrapolation according to the invention has come about. It is advantageous if the measurements relating to the ink transport behavior of the arbitrary roller have a relation to the same printing press or to the same inking unit, that is, if at least one of the measurements underlying the measurement series has been made there.

Extrapolation data is obtained from the comparison of the data. This is already possible in an advantageous manner by obtaining a normalization factor. The normalization factor is determined in such a way that the course of the spectral intensity of the remitted light with the smaller number of measurements N with the roller to be tested is readjusted with the course of the spectral intensity of the remitted light in the measurements with or with respect to the arbitrary roller can. In this case, measurements should be made at the same or similar waste concentration. By or with respect to any roll means that in addition to true measurements, extrapolated or with a similar roll (such as the aforementioned gravure roll having a comparable surface area) measurements can be used. As already mentioned, measurements can be made in the same printing or inking unit and / or in a test inking unit.

From the ratio of the light intensities, a normalization factor can be obtained. For example, if a measurement of the light intensity in a spectral range with respect to the roller to be tested at a waste concentration of 25% results in a lower light intensity than the corresponding measurement of the desired roller, it can be assumed that the roller to be tested, for example, at 21% waste comparable result as the arbitrary roller produces at 25%. This assumption can be based on a whole series of blends. The assumptions may be based on empirical values or simply estimates.

The use of a color formulation software (often referred to as Ink Formulation Software) in this context offers favorable opportunities to calculate such normalization factors - so-called layer thickness factors. The mentioned color formulation software products provide the ability to control the spectral light intensities of the reflected light that they have be assigned by suitable sensors, the various influencing factors, such as different pigment types, the substrate or the like to assign.

For this assignment, the color recipe software requires the spectral data of the colors from a color assortment that was generated with the desired roller (reference roller) or with the corresponding test stand. The typical field of application of these software products in the field of the printing industry is the control of the resulting print images. Thus, these software products can detect deviations from a desired color location and suggest corrective measures (mixture of a correction color).

For this purpose, the software should at least "know" the type of optical activity of the correction color (the course of the spectral light intensity of the reflected light is stored in the software's access).

In the present context, it is possible, with the basic possibilities that such a software offers, to better allocate the causes of a deviation in the color impression between the test roller and the desired roller. Thus, a deviation, especially in certain wavelength ranges, is due either to the pigments which are optically active in these regions or to a substrate which is optically active in this region. In the latter case, the blending or color transport behavior of the roller is an important influencing factor. In the former case, different color pigments are transported differently. More complex normalization functions offer the opportunity to optimally address all of these different causes of deviation. So it is better possible to better match the color mixture to be printed and the ink transfer rollers

An advantageous possibility to use the method according to the invention is to test the roller to be tested immediately in the printing press, which is to process a print job with the printing ink having the specific pigment composition. It is advantageous here, first a relatively small amount of color with a blend / pigment mixture ratio, which can cause the desired color impression, in the printing press too place. In this way, there is more scope for the subsequent corrections.

After examining the printed image produced on the machine, it can be compared with the data on the color transport behavior of any given roller. As already mentioned, it is advantageous if this data takes into account at least one measurement made with the arbitrary roller in the same printing or inking unit.

As a rule, the comparison of the test data and the data on the arbitrary roller will reveal differences which can be remedied by suitable measures on the printing machine. On the basis of the calculated normalization factor (layer thickness factor), a recipe software is able to adjust the concentration of the color pigments and the blend.

The printing speed also has an influence on the color transport behavior and can be used in this context. In printing processes such as gravure printing and flexographic printing, the thickness of the ink application can also be influenced by the relative position of the rollers involved in ink transport. An increase in the thickness of the paint job has a similar effect as a reduction in the proportion of waste in the paint. In other printing processes such as offset printing, the adjustment of the zone screw has a similar role, which influences the thickness of the ink application.

Notwithstanding the above, it is advantageous to first adjust the inking by the aforementioned mechanical measures (adjustment of the relative positions of ink involved rollers and / or the zone screw) before the test data is recorded. Advantageous methods to regulate the relative position on the inking rollers involved go from the EP 12 493 46 B1 and the DE 101 15 134 A1 out. Accordingly, the relative position can be adjusted by means of optical measurements of the printed image. For this purpose, it is proposed, inter alia, to record the course of the spectral intensity of the remitted light, while the rollers are pressed against each other during the printing. If a certain course of the light intensity sets in, then the optimal position is reached. Similar results can also be achieved if the captured print images are compared with target images or setpoints. It has been shown that for the purposes of these automatic roll setting methods, densitometric measured values can be used simply and advantageously. These can be obtained either by scanning the printed image with a densitometer or by reducing, for example, spectrophotometrically to densitometric measured values.

The significance of the test data can also be increased by, inter alia, varying the already mentioned pressure parameters between at least two measurements.

An apparatus for determining the specific color transport behavior of a ink-transporting roller for a printing ink, which has a certain pigment composition, requires an interface via which data can be fed to the device of an optical measuring device.

As far as the prior art blend series have been visualized by means of computers, such devices should also be state of the art.

• dass die Vorrichtung so eingestellt ist, dass sie Testdaten mit Daten zum Farbtransport einer beliebigen Walze vergleicht,
• wobei die Testdaten auf optischen Messungen an zumindest N Druckbildern beruhen, die unter Verwendung der zu testenden Walze mit einer Anzahl N von Mischungsverhältnissen der Pigmentzusammensetzung zu Verschnitt in der Druckfarbe hergestellt wurden,
• wobei die Daten zum Farbtransport einer beliebigen Walze auf optischen Messungen an zumindest M Druckbildern beruhen, die unter Verwendung der beliebigen Walze mit einer Anzahl M von Mischungsverhältnissen der Pigmentzusammensetzung zu Verschnitt in der Druckfarbe hergestellt wurden,
• wobei die Anzahl M größer ist als die Anzahl N von Testmessungen,
• und wobei die Vorrichtung so eingestellt ist, dass sie auf der Grundlage des Vergleichs Extrapoiationsdaten gewinnt, die das Farbtransportverhalten der zu testenden Walze extrapolieren.

Such a device is further developed according to the invention,

• that the device is set up to compare test data with ink transport data of any roller,
• the test data being based on optical measurements on at least N printed images produced using the roller to be tested with a number N of mixing ratios of the pigment composition to blends in the ink,
• the color transport data for any given roll being based on optical measurements on at least M printed images produced using the optional roll with a number M of mixing ratios of the pigment composition to blends in the ink,
• wherein the number M is greater than the number N of test measurements,
• and wherein the device is adjusted to obtain extrapolation data based on the comparison that extrapolates the ink transport performance of the roller being tested.

The adjustment may be to program a suitable controller of a printing press or independent computer with sufficient hardware requirements. In general, the implementation of the method steps described above with a computer-like device set in this way is advantageous. In this case, preference is given to a control device of a printing press, since these can generally also adjust further printing parameters-such as the relative positions of rollers involved in the ink transport-directly.

Further embodiments of the invention will become apparent from the description and the claims.

Fig. 1

Eine Seitenansicht eines Flexodruckfarbwerkes

Fig. 2

Eine Veranschaulichung des Arbeitsablaufes beim Erstellen einer Verschnittreihe nach dem Stand der Technik

Fig. 3

Eine Veranschaulichung des Arbeitsablaufes beim Erstellen einer Verschnittreihe nach der Erfindung

Fig. 4

Ein Diagramm mit den Graphen 105 und 106

Fig. 5

Ein Diagramm mit dem Graphen 106

The individual figures show:

Fig. 1

A side view of a flexo inking unit

Fig. 2

An illustration of the workflow in creating a blend series of the prior art

Fig. 3

An illustration of the workflow when creating a blend series according to the invention

Fig. 4

A diagram with graphs 105 and 106

Fig. 5

A graph with the graph 106

In FIG. 1 An inking unit 8 of a central cylinder flexographic printing machine 2 is shown. This example is intended to illustrate some terms used, such as the color-transporting roller 41a.

Zentralzylinderflexodruckmaschinen 2 are used inter alia in packaging printing and often have eight to twelve such inking. 8

The scope of the functional components of the inking unit 8 is indicated by the rectangle 44. The application of the teaching of the present document to such a Zentralzylinderflexodruckmaschine 2 is advantageous. In general, it can be said that the adjustment of the printed image 9 after a change of a color-conveying roller 41, 41a plays a role, above all in the areas of the printing industry, in which low-viscosity inks 11 are printed.

These paints 11 are generally mixtures or solutions of color-active substances - usually color pigments - waste and solvents. Based on FIG. 1 can the color transport of a paint reservoir, the color is supplied from outside the printing press - here the paint bucket 10 - sketch to the substrate 6.

The color lines 13 establish the connection between the paint bucket 10 and the doctor chamber 40. In a paint conduit, paint 11 is directed to the doctoring chamber (as indicated by arrow 46) and in the other conduit 13 from doctoring chamber 40 to bucket 10 (as indicated by arrow 47). The ink flow in the ink ducts 13 of the printing press from and to the bucket 10 is therefore often referred to as a color cycle, but this is ambiguous, as well as color from the doctor chamber to the anilox roller 41, which rotates in the direction indicated by the arrow C, is delivered. The anilox roller 41 delivers the ink to the plate 43 of the plate roller 42, which rotates in the direction indicated by the arrow B. The printing substrate 6 is printed with the cliché while it passes through the printing gap 48 defined by the cliché roller 42 and counter-pressure cylinder 45.

The printing material is further promoted in the direction of rotation A of the impression cylinder, runs past the guide roller 49, is lifted from the impression cylinder 45 and examined by the optical measuring device 4. The light cone 7 represents the remitted from the printed image 9 light.

For the purpose of weighing or determining the color mass or the color volume of the relevant ink 11 on the printing machine 2 is in FIG. 4 only the weighing device 12, which monitors the weight of the bucket 10 shown. The color lines 13 could also be weighed. It seems more appropriate to determine their volume and thus to estimate or calculate the volume of the paint in the pipes. The doctor chamber 40 contains appreciable color volumes and therefore could also be weighed. In view of the vibrations prevailing in an inking unit, however, a weighing device was dispensed with at this point and moved in the same way as the volume determination in the color lines.

The color located on the rollers 41, 42 or the cliché in the broadest sense also belongs to the color contained in a color supply system. However, only a fraction of the paint once on one of the rollers returns to the paint bucket 10, so that the volume of this paint need not be taken into account, or only slightly, for example, to conclude the color composition of the paint after a color correction.

In the present context, both the cliché roller 42 and the anilox roller 41 could be referred to as a color-transporting roller, since both rollers 41, 42 transport color to the printing substrate 6. In reality, however, only blending rows to anilox rollers 41 play a role.

FIG. 2 is intended to clarify a method already described above for determining a series of blends. In a processing step I. is in an inking unit 8, which in principle the in FIG. 1 printed inking unit 8 is similar printed substrate 6 with the aid of the cliché roller 42a and the anilox roller 41 a printed. The anilox roller 41a is the test roller 11 transporting roller. As a rule, the cliché roller supplies a full-tone image for these test purposes and is equipped with a corresponding cliché 43. It would be possible to print 8 to 12 consecutive times with different blend concentrations on a printing press 2 in another even more elaborate method of the prior art, wherein the color 11 different waste concentration would have arrived on the klichee each time the measurements take place. This is already avoided today as the amount of waste, unusable ink and machine downtime would be too high as a result of the tests.

Instead, it is known, in a second processing step, to cut off a part of the printing material 58 and to examine it in a spectrophotometric measuring station 60 by means of a spectrophotometer 54. Here, the color location reached in the printed image 9 is detected.

In a third processing step, a test inking unit 100, which is constructed here not by the flexographic printing principle but by the gravure printing principle, is printed with a test gravure cylinder 101. The gravure printing cylinder 101 has very high surface areas different engraving. For printing, the same color and the same amount of waste as in processing step 1 are selected.

The resulting printing substrate 6 (or the printed images 9) is examined. The area of the printing material (along the working width) in which the color impression most closely matches the color impression of the first working step (using the roller 41a to be tested) is selected. The area of the test gravure cylinder 101 which has printed this area is determined.

Another special gravure cylinder 102 is made which has the surface properties of this area of the test gravure cylinder.

The test gravure printing unit 100 is equipped with the special gravure cylinder 102, and it is printed with the color having different waste concentration (processing step V.). The investigation of the resulting printing material sections 58 in the measuring station 60 now provides a series of cuts, which is based on at least one measurement on the actual printing or inking unit 8 and thus on the printing machine 2.

FIG. 3 shows the sequence of an embodiment of a method according to the invention. Again, in a first processing step I. printed in a flexographic inking unit. Again, the roller to be tested is the anilox roller 41 a. The printed image is examined, whereby the color location is determined. The investigation can also be made on-line if a suitable spectrophotometer 54 is used for this, or if spectrophotometric data are approximated with densitometric data. This is for example in the still unpublished German patent applications with the application numbers 102007059176 . 102007059175 and 102007059177 as well as in the still unpublished application PCT / EP 2008/000992 described. The relevant passages of these documents are hereby expressly referred to and they are included in the scope of the present document.

The measurement results are transmitted to a suitable computer-like device 3, which may also be the control device 3 of a printing machine 2. This apparatus 3 is known a waste series, which was made for any anilox roller 41b, preferably on the same printing unit, preferably at the same color (pigment composition). Based on these data, the computer-like device 3 extrapolates the blend row for the roller 41 a to be tested.

FIG. 5 FIG. 10 shows a diagram 103 in which the intensity value I _{R of} the reflected light was recorded and plotted over the wavelength λ. As mentioned, a series of blends consists of a plurality of such graphs which were taken up at different blending concentrations (blending ratio blending into color-active substances or pigments) of the same color. In FIG. 4 is symbolized that a theoretical spectral course graph 105 is extrapolated on the basis of a symbolized by the graph 106 real spectral course (measured values).

Corrections of the color composition of the ink 11 in the paint bucket 10 can be made, as in the aforementioned yet unpublished German patent applications with the application numbers 102007059176 . 102007059175 and 102007059177 as well as in the likewise still unpublished PCT / EP 2008/000992 is described. The relevant passages of these documents are hereby expressly referred to and they are included in the scope of the present document.

This applies in particular to the passages which describe and claim a color correction with a decentralized, advantageously mobile color mixing device. Reference list Oak 2 press 3 Control device of the printing press 4 Optical measuring device 5 control line 6 substrate 7 light cone 8th Printing / inking 9 print image 10 paint bucket 11 Color / color mixing 12 weighing device 13 paint line 40 blade chamber 41 anilox roller 42 cliché roller 43 cliche 44 rectangle 45 Impression cylinder 46 Arrow (color conveying direction) 47 Arrow (color conveying direction) 48 nip 49 guide roll 54 spectrophotometer 58 Section of the substrate 60 Station for spectrophotometric examination 61 Color supply system 100 Test inking 101 Test gravure roll 102 Special gravure roll 103 Graph / Chart 104 square 105 Graph / diagram (theoretical spectral distribution, extrapolated values) 106 Graph / diagram (real spectral history, measured values) 41 a Anilox roller to be tested 41 b Any anilox roller 42 a Impression cylinder / die cylinder (for test purposes) A Arrow (direction of rotation of impression cylinder) B Arrow (direction of rotation of the cliché roller) C Arrow (direction of rotation of anilox roller) z Arrow (conveying direction of the printing substrate 6) I _R Intensity of the remitted light λ Wavelength of the remitted light

Claims (13)

Method for determining the specific color transport behavior of a color-transporting roller (41a) for a printing ink (11) which has a specific pigment composition, - In which the roller to be tested (41 a) in a printing unit (8,101) is used and printing substrate printed with ink of this pigment composition in which the pressure is carried out at least at a number N of mixing ratios of the pigment composition to waste, - And in which at least a part of the printed image (9), which is generated using the roller to be tested (41 a) is examined with an optical measuring device (4), wherein test data are obtained, characterized - that a control device (3) compares the test data with data on the ink transport behavior of any roller (41b) in that, as data for the color transport of the arbitrary roller (41a), data are used which have been carried out on the basis of the pressure with at least a number M of mixing ratios of the pigment composition to waste, which is greater than the number N. and that extrapolation data is extrapolated from the comparison, which extrapolates the ink transport behavior of the roller (41a) to be tested. Process according to the preceding claim
characterized in that
the extrapolation data represents a normalization function, which may also be a normalization factor. Process according to the preceding claim
characterized in that
at least a part of the data for color transport of the arbitrary roller (41 b) are obtained on the basis of measurements of printing material (6) printed with a test printing unit (100). Method according to one of the preceding claims
characterized in that
at least some of the test data are obtained on the basis of measurements of printing material (6) printed with a printing press (2). Process according to the preceding claim
characterized in that
from the extrapolation data control commands to devices and / or recommendations to the operator are obtained, which relate to printing parameters that affect the density of the ink application to the printing machine (2). Method according to one of the two preceding claims
characterized in that
the printing parameters, which influence the density of the ink application on the printing machine (2) and for which control commands or recommendations to the operating personnel are obtained, comprise at least one of the following variables, the concentration of the color-active substances and the solvents in the paint (11), the relative position of at least two rollers (41, 41a, 42, 42a) of an inking unit (8, 100) involved in the color transport to the printing substrate, - the adjustment of zone screws, with which the color transport in the direction is controlled to the place of action of the roller to be tested (41 a), - The speed at which the substrate (6) during printing by the printing press (2) is performed. Method according to one of the preceding claims
characterized in that - The print image (9) in a printing machine (2), in which the color transport is also controlled by a change in the relative position of at least two on the color transport to the substrate (6) rollers (41,41a, 42,42a) is controlled, such as in a flexographic printing (2) or gravure printing machine, - And that the relative position is at least preset before the measurement of the comparison data takes place. Process according to the preceding claim
characterized in that
the relative position of at least two rollers (41, 41a, 42, 42a) involved in the color transport to the printing material (6) is adjusted against the background of optical, preferably densitometric, measured values. Method according to one of the preceding claims
characterized in that
the test data comprise color intensity values (I _R ) from the visible wavelength range and are preferably based on a spectrophotometric measurement or a densitometric measurement with which the results are approximated by a spectrophotometric measurement. Method according to one of the preceding claims
characterized in that
the test data is obtained from a plurality of (M) individual measurements. Process according to the preceding claim
characterized in that
At least two of the individual measurements, which are based on the test data and / or the data on the color transport behavior of the arbitrary Walxes (41 b), take place at varied pressure parameters. Process according to the preceding claim
characterized in that
at least one of the following variables belongs to the varied pressure parameters: the concentration of the color-active substances and the solvents in the paint (11), the relative position of at least two rollers (41, 41a, 42, 42a) of an inking unit (8, 100) involved in the color transport to the printing substrate, - The adjustment of zone screws, with which the color transport in the direction of the place of action of the roller to be tested (41 a) is controlled - The speed at which the substrate (6) during printing by the printing press (2) is performed. Apparatus (3) for determining the specific color transport behavior of a ink-transporting roller (41a) for a printing ink (11) having a specific pigment composition,
which has an interface through which the device data of an optical measuring device (54) can be fed
characterized, - that the device (3) is set to compare test data with data for color transport of any roller (41 b), - wherein the test data on optical measurements are based on at least N print images using the test roller (41 b) were prepared by a number N of mixing ratios of the pigment composition to blend in the printing ink (11), - wherein the data for color transport of any roller (41 b) based on optical measurements on at least M printed images, using the roller to be tested (41 b) with a number M of mixing ratios of the pigment composition to blend in the ink (11) were produced, wherein the number M is greater than the number N of test measurements, and wherein the device is set to obtain, based on the comparison, extrapolation data extrapolating the ink transport behavior of the roller to be tested.

Images