DE102024131525A1 - Object with a security imprint, system and method for forming a security imprint - Google Patents

Abstract

An object (2, 10) comprises a security print which has a print arranged or formed on the object (2, 10) and which includes at least one CMY element formed by printing from a predetermined composition consisting solely of the printing inks cyan (C), magenta (M), and yellow (Y) with a predetermined print density, predetermined mixing ratio, and predetermined color position, such that it is perceived as black or dark in the spectral range visible to the human eye and is transparent in a spectral range invisible to the human eye. The CMY element interacts with another element arranged on or formed with the object (2, 10) which is perceptible in the spectral range visible to the human eye and is absorbent in the predetermined invisible spectral range.

Description

The present invention relates to an object with a security imprint and a method for applying a security imprint to an object. The invention further relates to a system comprising a container and a security imprint applied thereto.

Labels can serve for authorization or proof of origin and are used wherever it is necessary to identify or verify objects. For example, labels are used to mark objects to indicate their authenticity. In some cases, it may be desirable to store information discreetly and, for example, to establish a secure proof of authenticity. In such cases, it is desirable to be able to store such information securely and cost-effectively.

The invention aims to provide a security feature that enables information to be stored reliably and securely in a simple, flexible and cost-effective manner.

The problem is solved by the features of the independent patent claims. Advantageous further developments are specified in the respective dependent claims.

According to one aspect of the invention, an object comprises a security imprint having at least one imprint arranged or formed on the object, and comprising at least one CMY element formed from a predetermined composition consisting solely of the printing inks cyan, magenta, and yellow. The printing inks cyan, magenta, and yellow, with a predetermined ink density, mixing ratio, and color position, form the CMY element by means of printing such that it is perceived as black or dark in the spectral range visible to the human eye and is transparent in a spectral range invisible to the human eye, in particular an infrared and/or ultraviolet spectral range. The CMY element is configured in conjunction with a further element arranged on or formed with the object, which is perceptible in the spectral range visible to the human eye and is absorbent or opaque in the predetermined invisible spectral range.

The described security printing on the object allows for the implementation of a security feature that enables the reliable and secure storage of information in a simple and cost-effective manner. In particular, the CMY element can be used as an overprint on a designated part of the object, creating a visual barrier that appears black or dark to the naked eye, but which is transparent when examined using tools such as an infrared or ultraviolet camera, revealing underlying information. This information can be a print, a marking, a relief, a colored element, or something similar, and can be partially or completely covered by the CMY element, thus forming the security feature.

The CMY element accordingly has a color coordinate that can be described as black. Alternatively, the CMY element can also be configured to have a color coordinate that can be described, for example, as dark blue, dark green, or dark red. The CMY element can thus be configured with a desired dark color coordinate and transparently reproduce any dark IR-absorbing color. The CMY element is configured to match a color coordinate of the other element with which it is intended to interact as a security print. For example, the CMY element can be configured as a dark blue print that interacts with a dark blue element. In the following description, the invention is primarily described using a black CMY element. However, this is not to be understood as limiting and can also be applied to other dark or tinted colors.

The item can be designed as a container on which the security markings are applied or printed. Alternatively, the item can be, for example, a cardboard or carton package on which the security markings are applied or printed. In particular, the item can be designed as a security label and have one or more label layers on which the security markings are printed. Such a security label provides a reliable means of concealing information. Additionally, the security label can include one or more functional layers, such as barrier layers against the unwanted passage of a specified gas, molecular substance, UV light, and/or other electromagnetic radiation. Furthermore, the security label can include predefined cuts, die-cuts, or perforations, a sealing function, and/or a void layer, which can contribute to increased security.

According to a preferred embodiment, the CMY element interacts with one or more other printing elements, which realize the other element. The printing on the object can, in particular, include a K element formed from black printing ink, such that it is perceived as black in the visible spectral range and is absorbent or opaque in the infrared spectral range. The color and/or brightness appearance of the CMY element and the K element, as perceived by the human eye, are coordinated.

The CMY element, like the K element, can represent a single letter, a word mark, a symbol, a textured or solid area, and/or a desired print. The CMY element can be illuminated using an infrared or ultraviolet sensor, for example, in the form of an IR or UV camera, and/or, in security printing, it can be omitted during viewing, so that only the elements that are absorbing in the corresponding spectral ranges remain visible against a reflective background. The CMY element does not necessarily have to be completely or 100% transparent in an IR or UV range, but rather sufficiently transparent to allow the desired transparency and a clear difference compared to viewing with the naked eye. For example, it may be sufficient for the CMY element to be printed in such a way that it is at least 50% transparent in an infrared or ultraviolet spectral range compared to viewing in the visible spectral range. Preferably, the CMY element is configured to have a transparency of over 75% or even over 90% in a predefined non-visible spectral range, thus becoming almost invisible compared to viewing in the visible spectral range. Furthermore, multiple CMY elements can be configured with different transparency properties, appearing as black or a predetermined dark in the visible spectral range and exhibiting different dark color points. For example, three CMY elements can be provided, one of which is 100% or nearly 100% transparent in a predefined IR range. The second CMY element might then be, for example, only 80% transparent in the IR range, and the third CMY element, for example, only 50% transparent.

The same applies to the absorption of the K element, meaning it doesn't have to be 100% infrared or ultraviolet absorbing, but must at least exhibit a value sufficient for clear differentiation from the transparent CMY element. Typically, the black (K) color in an inkjet printer contains a predetermined carbon black content, which is infrared-absorbing. The chromatic colors cyan (C), magenta (M), and yellow (Y) in an inkjet printer generally contain no carbon black, making them infrared-transparent.

Furthermore, the CMY element is not necessarily transparent across the entire infrared or ultraviolet spectral range. The spectral range typically visible to humans extends, for example, from 400–800 nm or 380–780 nm, encompassing the colors violet through blue, green, yellow, and red. The infrared spectral range then extends above 780 nm down to, for example, 3 µm. The CMY element can, for instance, be designed to be transparent in a near-infrared range of 800–1000 nm or 900–1200 nm. The ultraviolet spectral range is typically set below 380 nm and extends, for example, down to 200 nm. Beyond this, other wavelength ranges can also be considered for a non-visible spectral range, allowing for evaluation using assistive devices.

As an alternative to the described limits and spectral ranges, other values for the corresponding wavelengths of electromagnetic radiation can also be specified. For example, there are infrared cameras that have two different operating modes, one at approximately 850 nm and a second at approximately 950 nm. Accordingly, the security feature could be designed to have a specific appearance in the visible spectrum and up to a limit of 900 nm, while exhibiting a different appearance above 900 nm. However, the visible spectral range is always perceptible to the human eye, while the invisible range is not and therefore requires visual aids. In the following description, the invention is primarily described in connection with a CMY element that is transparent in an infrared spectral range. However, the properties and features are transferable to other ranges invisible to the human eye.

According to further training, with reference to a given color space, such as the Lab color space, a CMY color point is assigned to the CMY element and a K color point is assigned to the K element. A mixing ratio of the printing inks cyan, magenta, and yellow for creating the CMY element is specified such that the CMY color point and the K color point coincide within a predefined tolerance range. Alternatively or additionally, A droplet size and/or droplet density of the black printing ink is specified to form the K element such that the CMY color coordinates and the K color coordinates match within a specified tolerance range.

Especially when the black CMY element and K element (in the visible spectral range) interact in security printing to create a reliable and secure security feature, it is beneficial to coordinate and adjust their color and/or brightness appearance. This is particularly advantageous when the CMY and K elements are positioned next to each other from a given viewing angle and, for example, form a shared print such as text or an address. Ideally, the black of the CMY element and the black of the K element should be identical or at least so similar that they are indistinguishable to the human eye. Thus, for example, text such as "Original" can be concealed within an address, provided the address already contains the corresponding letters. The letters of the word "Original" are then designed as K element(s), while the remaining letters are designed as CMY element(s). In the visible spectrum, the entire address can be read; when viewed in the infrared spectrum, only the word "Original" is recognizable or at least clearly distinguishable from the other elements. This allows for secure and reliable verification of the item.

Alternatively or additionally, a symbol or character string with predefined CMY and K elements can be printed. For example, dots can be printed as K elements along a line or predefined gradient and overprinted and hidden by one or more CMY elements. Within the dot structure and the overprinted structure, an object-specific or static code can be implemented, depending on the sequence and number of IR-transparent and IR-absorbing elements.

Even if the CMY element and the K element are arranged one above the other, either alternatively or additionally, relative to a given viewing angle of the object, these elements are preferably coordinated and adapted to each other with regard to their color and/or brightness appearance. This is preferably the case when the K element is formed beneath the CMY element and thus positioned between a surface of the object and the CMY element. The CMY element can completely or partially cover the K element. For example, the K element is printed in black as the word "Original" and is infrared-absorbing. Alternatively, the CMY element can be formed as a solid black area and completely covers the K element. The two black values, or the corresponding color coordinates of the CMY element and the K element, should then be designed such that the K element is not darker or deeper black and does not show through the CMY element. The security printing can then be carried out entirely using digital printing, for example, by first printing the black ink to form the K element in a predetermined printing sequence, followed by printing the cyan, magenta and yellow inks to form the CMY element.

According to a further development of the object, with respect to a viewing direction of the object, the printing colors cyan, magenta and yellow of the CMY element are aligned relative to each other and printed on top of each other, so that they have a registration structure deviation of one pixel or less relative to each other.

According to a preferred embodiment, the label is designed as a security label and has at least one label layer on which the security printing is applied. The colors of a CMY element are then printed on the label layer, in particular in direct contact with each other. Alternatively, the colors of a CMY element can be printed separately on the label layer or on different layers of the security label.

The security label, for example, is multi-layered and designed to wrap around a container multiple times, for example, three times. The process colors cyan, magenta, and yellow are printed at predetermined intervals on the label layer, so that the CMY element is partially formed on one or more layers of the security label in such a way that, after the security label is properly applied to a substrate or the outer surface of the container, the CMY elements combine to form a single, unified CMY element. When the security label is wrapped around the container, for example, cyan is printed on the bottom layer facing the container, magenta on the middle layer, and yellow on the top layer facing away from the container. These overlapping elements together form the CMY element. The process colors can also overlap in a different predetermined sequence. Thus, the overlap of the three process colors, which do not directly contact each other due to the label layer, allows for the creation of a single, unified CMY element. The infrared-transparent CMY element can be formed. In this way, information printed at a customer's site can be covered with an infrared-transparent area or part thereof, or the content of the information can be specifically modified, and only after the infrared-transparent area is removed as a removable part can the true or intended information or an alternative second piece of information be made accessible.

According to a further aspect of the invention, a system comprises a vessel, such as a syringe, vial, or injection bottle, with a vessel closure and a vessel body, and an embodiment of the previously described object in the form of a security label arranged on the vessel. The security label can be affixed to the vessel body and/or the vessel closure and may partially or completely wrap around them. The security label can therefore be designed as a wraparound or over-wrap label. Since the described system comprises an embodiment of the previously described object, the described properties and features of the object and the security imprint are also disclosed for the system, and vice versa.

According to a further aspect of the invention, a method for forming a security imprint on an object comprises providing the object and forming the security imprint on the object by applying a print. The print has at least one CMY element, which is formed by printing from a predetermined composition consisting solely of the printing inks cyan, magenta, and yellow with a predetermined print density, predetermined mixing ratio, and predetermined color position, such that it is perceived as black in the spectral range visible to the human eye and is transparent in a spectral range invisible to the human eye, in particular an infrared or ultraviolet spectral range. The CMY element interacts with a further element that is arranged on or formed with the object and that is perceptible in the spectral range visible to the human eye and is absorbent in the predetermined invisible spectral range.

The described method is specifically designed for manufacturing a version of the previously described object with the security printing. Therefore, the described properties and characteristics of the object and the security printing are also disclosed for the method, and vice versa.

According to a further development of the procedure, the formation of the security printing includes forming the printing and/or a further printing which includes a K-element formed from the printing ink black, so that it is perceived as black in the spectral range visible to the human eye and is set to be absorbent in the spectral range not visible to the human eye, wherein a color appearance and/or brightness appearance of the CMY element and the K-element, perceptible to the human eye, are set to be coordinated with each other.

According to a further development of the method, the training of the security print comprises determining a color coordinate of the K-element with respect to a predefined color space, and adjusting a mixing ratio of the cyan, magenta, and yellow printing inks for the CMY element depending on the determined color coordinate of the K-element, such that a color coordinate of the CMY element and the color coordinate of the K-element coincide within a predefined tolerance range. Alternatively or additionally, the method can be configured such that the training of the security print comprises determining a color coordinate of the CMY element with respect to a predefined color space, and adjusting a droplet size and/or droplet density of the black printing ink for the K-element depending on the determined color coordinate of the CMY element, such that the color coordinate of the CMY element and a color coordinate of the K-element coincide within a predefined tolerance range.

According to a further development of the procedure, the formation of the security printing includes forming the K-element by printing with the printing ink black, and subsequently forming the CMY-element by printing with the printing inks cyan, magenta and yellow, so that, with respect to a viewing direction on the object, the K-element is formed under the CMY-element.

According to a further development of the process, the training of the security printing includes determining the registration structure accuracy of the printing inks cyan, magenta, and yellow relative to each other, and aligning the respective printing positions of the printing inks cyan, magenta, and yellow depending on the determined registration structure accuracy. The process further includes training the CMY element by printing with the aligned printing inks cyan, magenta, and yellow, such that when printed on top of each other, they exhibit a registration structure deviation of less than one pixel.

By means of the described security printing on the object and the corresponding manufacturing process, a security feature can be implemented, for example by printing the infrared-absorbing black K-element and the infrared-transparent CMY element together in an inkjet print.

It is a finding related to the present invention that the conventional black printing ink, abbreviated with the letter K, is absorbing in the near-infrared range by industrial inkjet printheads, and therefore not transparent. Using the CMY element, black text in the visible spectrum can be produced that is not created with conventional black inkjet ink K, but rather from a precisely defined mixture of the three other process colors cyan, magenta, and yellow, abbreviated with the letters C, M, and Y. The black CMY element thus created has the property of being transparent in the infrared.

Another finding related to the present invention is that, in practice, it is not usually possible to change the inkjet printing inks in an inkjet printing press. To use an infrared-transparent black inkjet printing ink in a series production product, an additional inkjet printhead would be required on the corresponding inkjet printing press. This is very costly, firstly due to the additional purchase costs. Secondly, it also presents challenges in practical operation. An infrared-transparent ink is a special ink that is complex to produce and is only needed for creating this particular infrared-transparent feature, and is therefore not used regularly. However, if an inkjet printhead is not used regularly, the risk of individual nozzles becoming clogged increases significantly. This represents a serious disadvantage and leads to increased maintenance costs.

Using the described security printing technique and the CMY element it contains, a visible black ink can be created cost-effectively, flexibly, and with minimal effort from a mixture of the three existing process colors: cyan, magenta, and yellow. This ink also possesses the property of being transparent in the near-infrared, offering serialization capabilities and contributing to increased security. The black ink, or rather the CMY element, is therefore not produced with conventional black inkjet ink, but can be used effectively in conjunction with such ink and the resulting CMY element.

When working together, particular attention must be paid to coordinating and adjusting the color and brightness appearance of the CMY and K elements. In practice, printing on an object often includes not only the infrared-transparent black built from CMY, but also one or more K elements, which are created using regular K inkjet printing ink. To ensure that the difference between these two variants—CMY and K—is not noticeable, it is beneficial to harmonize their appearance in terms of both color and brightness. This can be done through testing, for example, by initially printing two black areas onto a layer and comparing them. The first black area represents the K element, which can be assigned a red-green-blue (RGB) color code, such as 34/35/32. A black area printed with inkjet process ink K then has approximately equal color components R=34, G=35, and B=32 in a photograph. According to this example, the second black area forms the CMY element, which is composed of the inkjet process inks CMY. In contrast to the first area, the color component G=37 initially dominates, for example, compared to R=20 and B=26.

Verification can also be performed with a colorimeter and assessed according to an assigned color space. The Lab color space, derived from the CIEXYZ color space, is suitable for this purpose. The Lab color space is standardized and structured so that the degree of perceived brightness (L) is perpendicular to a color plane (a, b). For example, a black CMY element can initially be created with the RGB values specified above. When printed with all three process colors at maximum ink density, this element, with values of L=10.6, a=-15.6, and b=4.1, is not as color-neutral as the pure inkjet process color (K) with L=4.1, a=-2.7, and b=0.3. In comparison, a white reference film has the values L=84.8, a=-0.8, and b=-2.1.

Accordingly, in a next step, the printing properties of the CMY element colors and/or the printing properties of the K element color can be adjusted to design the black area resulting from the combined printing of CMY ink so that its appearance is as identical as possible to that of the inkjet process color K. This can be achieved by adjusting the print density or the mixing ratio of the CMY components. In the present example, the color locus for the CMY black area is located with a=- 15.6 and b=4.1 in an ab-plane in the upper left with respect to the centrally located gray point. In the ab-plane, yellow points upwards, magenta to the right, and cyan downwards and to the left. Therefore, it is beneficial to reduce the cyan and yellow components appropriately to shift the color coordinates of the CMY area from a=-15.5 and b=4.1 towards the color coordinates of the K-plane with a=-2.7 and b=0.3. Reducing the cyan component corresponds to a color shift upwards and to the right in the ab-plane. Reducing the yellow component corresponds to a color shift downwards in the ab-plane.

In general, any color shift in the color plane of the Lab color space can be corrected by adjusting two of the three process colors, CMY and MY. Color neutrality can be achieved by specifically adjusting the CMY color combination. For example, a yellow tint can be eliminated by reducing the yellow component. Compared to the black K area, the black CMY area, for instance, exhibits a color shift of Δa = -15.6 - (-2.7) = -11.9 and Δb = 4.1 - 0.3 = +3.8. This color shift points to the upper left in the ab color plane of the Lab color space. Accordingly, the color shift can be corrected by appropriately reducing the yellow and cyan components. Similarly, the black of the CMY element can be adjusted to match the black of the K element so that there is no apparent color difference.

Furthermore, the perceived brightness, specified in the Lab color space by the L value, must be considered. For example, the black area formed by the inkjet process color K is initially darker (L=4.1) than the black area formed by the combined CMY (L=10.6). To make the CMY area darker, the ink density of the colors can be increased. However, the CMY process colors can only be printed at their maximum ink density, and if this is insufficient, the printing properties for the K element can be adjusted to match the two black areas. For instance, adjusting the combined CMY printing to match the brightness of the inkjet process color K can be achieved by reducing the ink density of the K. This can be accomplished, for example, by setting a smaller droplet size for the K. For example, an inkjet printhead with a maximum droplet size of 14 pl allows for a printed black K area with an L value of 4.8. A minimum droplet size of 3 pl with this inkjet printhead allows for a printed black K area with an L value of 39.8. Accordingly, the black of the K element can be adjusted to the L value of 10.6 for the black of the CMY element, so that there is no apparent difference in brightness. Droplet size is specified, for example, as volume in pico-liters (pl). Such drops have a diameter of approximately a few pico-meters, and upon impact with a printing substrate, the droplet spreads out in a predetermined manner over the area of a print pixel.

Alternatively or additionally, the inkjet process color K's print intensity can be reduced by selectively printing dots within the black K area with a smaller droplet size, or even eliminating or omitting them entirely. Reducing the droplet size of, for example, every second dot creates a print pattern with a higher luminance L. From a solid area to a checkerboard pattern and beyond, the brightness of the black K element to be printed with the inkjet process color K can be adjusted by regularly changing (i.e., the modified print pixels are arranged regularly to ensure uniformity of appearance) the desired number of dots. This adjustment allows the brightness to match that of the black CMY element built from the process colors CMY. Accordingly, the desired brightness can first be determined, and then a gray value with the corresponding brightness can be selected based on a color or grayscale calibration. Alternatively or additionally, a series of test areas can be printed based on the inkjet process color K with different shades of gray in order to identify the best possible shade of gray based on the match (or by interpolation between the two best matching test areas).

When the two black components, the CMY element and the K element, interact, it is therefore advantageous for secure and reliable security printing to design the respective color areas so that they have an appearance as identical as possible to each other in terms of both color and brightness. Furthermore, the CMY element and the K element can be coordinated with regard to a desired motif, thus enabling a wide variety of design options for security printing.

1. 1. Es kann eine Unterdruckung ausgeführt werden, die optional auch serialisiert einrichtbar ist. Bei einer solchen Unterdruckung wird das K-Element unter einer Deckschicht gedruckt bzw. angeordnet, welche durch das CMY-Element realisiert ist. Im sichtbaren Spektralbereich ist das CMY-Element blickdicht, während es im infraroten Spektralbereich transparent ist und eine Betrachtung des darunter befindlichen K-Elements ermöglicht. Das Erscheinungsbild eines Druckmusters weist dann im Sichtbaren zum Beispiel schwarz erscheinende Flächen auf, die bei Betrachtung im Infraroten transparent sind und dementsprechend verschwinden. Eine darunter befindliche Schrift, die im Sichtbaren überdeckt und daher nicht sichtbar war, kommt dann bei Betrachtung im infraroten Spektralbereich zum Vorschein, weil sie Infrarot-absorbierend ausgeführt ist. Dieser Unterschied zwischen dem Erscheinungsbild im sichtbaren Spektralbereich und dem Erscheinungsbild im nicht sichtbaren infraroten Spektralbereich stellt ein verstecktes und zuverlässiges Sicherheitsmerkmal bereit, das bei Bedarf geprüft werden und zum Beispiel eine Originalität verifizieren kann. Die infrarotabsorbierende Schrift unter der infrarottransparenten Überdruckung kann serialisiert ausgeführt werden. Alternativ oder zusätzlich kann auch die infrarottransparente Deckschicht in serialisierter Weise ausgeführt werden.
2. 2. Eine solche Unterdruckung des K-Elements kann auch in Form einer Mikroschrift ausgebildet sein, die beispielsweise bei einer Druckauflösung von 600 dpi und einer Schriftartgröße von 5 Pixeln in einer Schrifthöhe von ca. 212 µm oder bei einer Druckauflösung von 1200 dpi sogar nur halb so hoch, also mit einer Schrifthöhe von 106 µm ausbildbar ist und sicher und zuverlässig versteckt bzw. überdeckt werden kann. Die Überdruckung mit dem CMY-Element ist hinsichtlich einer Höhe oder Dicke entsprechend abgestimmt auf die Höhe bzw. Dicke des K-Elements auszubilden, sodass das K-Element versteckt in dem CMY-Element eingebettet ist und sich zum Beispiel nicht durch Erhebungen nach oben abzeichnet.
3. 3. Einzelne Motivelemente können als schwarze und IR-transparente CMY-Elemente gedruckt werden, die zusammen mit weiteren schwarzen und IR-absorbierenden K-Elementen eine Bedruckung einrichten. Die CMY- und K-Elemente können zum Beispiel nebeneinander angeordnet eine gemeinsame Bedruckung in Form einer Adresse einrichten, sodass bevorzugt die Schwärze des Drucks mit der K-Inkjet-Tinte an das etwas grauere Erscheinungsbild des Schwarz der CMY-Elemente angepasst ist. Dies kann, wie zuvor beschrieben, unter anderem durch die Verwendung kleinerer Tropfengrößen und/oder einer vorgegebenen Rasterung erreicht werden, bei der gezielt Druckpunkte in einer Fläche eliminiert oder kleiner ausgeführt sind als benachbarte.

There are several ways to shape the areas or elements made from the printing ink K and the printing inks CMY so that they can be used effectively as a security feature in the form of printing:

1. 1. Underprinting can be performed, which can optionally be set up for serialization. In such underprinting, the K-element is printed or positioned under a cover layer, which is realized by the CMY element. In the visible spectral range, the CMY element is opaque, while in the infrared spectral range it is transparent and allows the underlying K-element to be viewed. The appearance of a printed pattern then shows, for example, black areas in the visible spectrum, which are transparent when viewed in infrared and therefore disappear. Text underneath, which was covered and therefore not visible in the visible spectrum, then becomes visible when viewed in the infrared spectral range because it is infrared-absorbing. This difference between the appearance in the visible spectral range and the appearance in the invisible infrared spectral range provides a hidden and reliable security feature that can be checked if necessary and, for example, verify authenticity. The infrared-absorbing text beneath the infrared-transparent overprint can be serialized. Alternatively or additionally, the infrared-transparent top layer can also be serialized.
2. 2. Such underprinting of the K element can also be designed as micro-text, which, for example, at a print resolution of 600 dpi and a font size of 5 pixels, can be produced with a font height of approximately 212 µm, or at a print resolution of 1200 dpi, even only half that height, i.e., with a font height of 106 µm, and can be reliably and securely hidden or covered. The overprinting with the CMY element must be designed with a height or thickness appropriate to that of the K element, so that the K element is hidden within the CMY element and does not, for example, show through raised areas.
3. 3. Individual motif elements can be printed as black and IR-transparent CMY elements, which, together with other black and IR-absorbing K elements, create a print. The CMY and K elements can, for example, be arranged side by side to create a common print in the form of an address, so that the blackness of the print with the K inkjet ink is preferably adapted to the slightly grayer appearance of the black of the CMY elements. As described above, this can be achieved, among other things, by using smaller droplet sizes and/or a predefined halftone screen in which print dots in an area are selectively eliminated or made smaller than neighboring ones.

Especially with partial coverage, there will always be a border around the printed K and CMY elements. Therefore, the following considerations regarding registration accuracy should be applied to all three previously mentioned design variants. High registration accuracy can be particularly important for K and CMY elements printed side-by-side, as this is crucial for creating a reliable security feature. When implementing CMY combination printing in the form of letters or other small graphic elements, there are relatively many border areas where an imperfect combination of the CMY process colors can be noticeable. For a hidden security feature, it is beneficial to avoid a conspicuous border. For this purpose, registration test structures can be used to check the print positions of the process colors cyan, magenta, and yellow and, if necessary, align them. For example, cyan, as one of the three inkjet process colors, can be printed as a reference, perhaps as a line one pixel wide. Using the other two inkjet process colors, magenta and yellow, lines one print pixel wide are then printed above and below this line, extending it in a series such that these lines are shifted laterally or perpendicularly to the reference inkjet process color line by -2, -1, 0, +1, and +2 print pixels, respectively. If the printed inkjet process colors are not correctly aligned with each other, this will be noticeable in the printed image because the yellow and magenta lines will no longer align with the cyan reference lines at position 0 in the print template, but will instead align at one of the other positions -2, -1, +1, or +2, depending on the misalignment. A scale can then be used to read the existing misalignment and correct the adjustable alignment of the inkjet process colors relative to each other.

A corresponding analogous alignment can be performed in the opposite direction, so that, when viewing a piece of paper or a print, both the horizontal and vertical alignment of the three process colors cyan, magenta, and yellow can be checked and corrected if necessary. After successful alignment, a margin of the superimposed colors is aligned, ensuring the formation of the black CMY element. ments from the three colorful process colors are particularly reliably hidden.

Using the described security printing technique, a security feature can be created without requiring an additional inkjet printing unit to produce a black, infrared-transparent special color. The readily available process colors cyan, magenta, and yellow can be used cost-effectively and with minimal effort to create a black, infrared-transparent appearance, which, especially in combination with the black, infrared-absorbing process color K, can be used as a security feature. This avoids acquisition costs and also helps to prevent the higher maintenance costs associated with such a special color compared to standard CMYK printing colors. These maintenance costs would arise because an infrared-transparent special color is not used regularly and therefore more frequently causes problems with clogged inkjet print nozzles.

• 1-9 Ausführungsbeispiele einer Sicherheitsbedruckung an einem Gegenstand in verschiedenen Ansichten,
• 10-13 schematische Druckprozesse zum Ausbilden einer Sicherheitsbedruckung, und
• 14 ein Ablaufdiagramm für ein Verfahren zum Ausbilden einer Sicherheitsbedruckung an einem Gegenstand.

The following are exemplary embodiments of the invention explained with reference to schematic drawings. These show:

• 1-9 Examples of security printing on an object from different views,
• 10-13 schematic printing processes for creating a security print, and
• 14 A flowchart for a procedure for applying a security imprint to an object.

Elements or features of the same construction or function are identified across all figures using the same reference symbols. For clarity, not all depicted elements or features may be identified with their corresponding reference symbols in every figure.

The 1 to 9 Figure 1 shows exemplary embodiments of security printing on an object 2, 10. The object can, in particular, be implemented as a security label 10, which, for example, is affixed to a predetermined substrate for identification purposes. Such a security label 10 can be designed according to 9 attached to a vessel 2 and, for example, glued to a vessel closure 3 and a vessel body 4 of the vessel 2.

The security label 10 according to 1 The security label 10 features a security print comprising a print 11 and optionally one or more further prints, which are printed on a label layer 13. The security label 10 can be single- or multi-layered and preferably includes an adhesive layer on one underside so that it can be easily and reliably adhered to a substrate. The print 11 comprises one or more CMY elements, each formed by printing from a predefined composition consisting solely of the printing inks cyan (C), magenta (M), and yellow (Y) with a predefined print density, predefined mixing ratio, and predefined color location (sa). 13 The respective CMY element is printed in such a way that it is perceived as black in the spectral range visible to the human eye and is transparent in a spectral range invisible to the human eye. The spectral range invisible to the human eye is, for example, implemented as a near-infrared spectral range.

The print 11 further comprises one or more K elements, each formed from the printing ink black K, such that it is perceived as black in the spectral range visible to the human eye and is absorbent in the spectral range invisible to the human eye. The CMY element and the K element interact in the print 11, and a color appearance and/or brightness appearance of the CMY element and the K element perceptible to the human eye is coordinated in the visible spectral range. The hatched line element on the right of the label layer 13 in 1 It is intended to represent another CMY element and show that the printed elements can also be spaced apart from each other and represent a symbol or something similar.

The 1 The security label 10 shows a representation intended to depict the visible spectral range. The spectral range visible to the human eye is approximately in the wavelength range of 380 nm to 780 nm. 2 The security label shows 10 after 1 in a representation intended to depict observations in the non-visible infrared spectral range. For example, the near-infrared spectral range, invisible to the human eye, is roughly in the wavelength range of 800 nm to 1000 nm.

The print 11 can consist of a continuous print or a print with several spaced elements. The individual characters can each be designed as CMY elements or K elements and considered as separate elements. Alternatively, the CMY elements and the K elements can be combined into a single CMY component or K component, respectively. These are referred to as nente, which then has several spaced-apart sections. According to the 1 and 2 The letters A, C, E, and G, as well as the digits 1, 2, 4, 5, 7, and 8, are designed as K elements or K components. Against a light or reflective background, the K elements appear as dark printed characters in both the visible and infrared spectral ranges. The remaining letters B, D, F, and H, as well as the digits 3, 6, and 9, are CMY elements. In the visible spectral range, they appear as black printed characters, but they are transparent in the infrared spectral range and therefore disappear when viewed under such conditions, for example, with an infrared camera. The following discussion will primarily focus on a single K or CMY element, as its properties and characteristics also apply to the other K or CMY elements or are transferable to the K or CMY components.

Based on the 2 It can be seen that information can be hidden in the security printing, which is only visible when viewed with an infrared camera. The respective CMY elements disappear under such viewing conditions, and the printing 11 remains partially visible with the K elements, which now, for example, reveal a specific piece of information. The CMY element and the K element are arranged side by side and work together to form a security feature. According to this design, it is advantageous to align and adjust the black values or the corresponding color coordinates of the K element and the CMY element so that no difference exists or is perceptible in terms of color and brightness when viewed in the visible spectral range.

The deepest and darkest black used to render the K element is typically richer and darker than the deepest and darkest black used to render the CMY element. To achieve this, the mixing ratio and ink density of the process colors cyan (C), magenta (M), and yellow (Y) can be adjusted so that the CMY element appears as dark or black as possible. The K element can then be modified with regard to its blackness by not printing it as deep a black as possible, but rather by adapting it to the capabilities of the CMY element. For example, the droplet size and/or droplet density of an ink, which are adjustable in inkjet, laser, or digital printing, can be reduced. This allows the K element and the CMY element to be rendered as indistinguishable blacks in the visible spectral range for the human eye. Using forensic tools such as a magnifying glass or microscope, the K element and the CMY element can be distinguished, particularly based on their edge sharpness. For example, in relation to a top view, each K element has perfect edge sharpness or edge sharpness that is distinguishable from the imperfect edge sharpness of a CMY element.

The 3 and 4 Figure 1 shows another embodiment of the security label 10 in a schematic top view. The printing 11 again comprises K elements and CMY elements that work together to establish a reliable security print. 3 Security label 10 is shown again in a representation intended to depict a view in the visible spectral range. 4 The security label shows 10 after 3 in a representation intended to depict observation in the non-visible infrared spectral range. The print 11 comprises numerous inscriptions of the word "Original," arranged in rows and each designed as a K-element. In every second row, these inscriptions are covered by a solid black area, each designed as a CMY element, i.e., in the visible spectral range (see...). 3 ) can be seen in the invisible infrared spectral range (see 4 ) but are not visible, thus allowing a view of the text underneath. Alternatively, instead of the word "Original", another term or symbol, such as a correction checkmark, a company logo, or an emblem can be used, which is hidden by a CMY element.

The color coordinates of the respective K and CMY elements are aligned, and preferably their print height or thickness is also coordinated, so that an overprinted K element does not show through or appear raised as a relief. For example, the CMY element is designed to be slightly taller than the font height of the K element, so that the latter is completely embedded within the CMY element. Infrared viewing reveals the overprinted K elements, as they are infrared-absorbing, while the solid CMY elements are infrared-transparent. Such an embodiment can be described as underprinting, since K elements are printed beneath the CMY elements. This can be achieved, for example, using digital printing in the form of an inkjet printing process, where the printhead sequence is predefined as K-CMY (see...). 12 ), as an alternative to the usual CMYK sequence.

The safety feature according to the embodiment as described in the 3 and 4 This therefore includes sections with two printed layers on top of each other. The upper layer features full-surface CMY elements. The upper layer consists of elements that are black in the visible spectrum but transparent to infrared light and can be printed using inkjet printing with the standard CMY colors. The lower layer comprises K-elements in the form of lettering, which are recognizable as black in the visible and infrared spectral ranges and are printed with the K color available in inkjet printing.

The 5 and 6 Figure 1 shows a further embodiment of the security label 10 as well as coding variants that are made possible by the security printing of the security label 10. 5 Security label 10 is shown in a representation intended to depict viewing in the visible spectral range. In print 11, the letters B, E, G, and J are transparent in the infrared spectral range as CMY elements, while the remaining letters A, C, D, F, H, and I are infrared-absorbing K elements and therefore still visible in the infrared spectral range.

6 Tabular illustration of possible coding variants for security label 10 5 The first line lists the characters or letters. The second line shows their respective representation in the infrared spectral range. The third line indicates the type of the corresponding letter, where, for example, the letters A and D are infrared-absorbing ("abs.") and the letters B and E are infrared-transparent ("transp."). The fourth line indicates a binary assignment, with the value 1 assigned to K elements and the value 0 to CMY elements. The fifth line indicates the position of each letter, starting with the first letter A at position 0. The sixth line shows the power of 2 corresponding to that position. The last line lists the powers of 2 assigned to the K elements. The table at the bottom right shows the sum of the powers of 2 for the K elements.

Accordingly, a sequence of letters can also represent a binary number using the IR-transparent CMY elements or the IR-absorbing K elements. If a fixed number of letters is chosen (e.g., block size 8), then an integer covering a range from 0 to 255 can be represented. Using a code (e.g., ASCII encoding), this number can stand for any character. Instead of the string "ABCDEFGHIJ", as in 5 Any code text could be chosen. Spaces between words can be ignored. The IR-absorbing letters A, C, D, F, H, and I are identified with the binary digit 1, but could alternatively be assigned the binary value 0. The same applies to the remaining IR-transparent letters B, E, G, and J. This results in the digit sequence 1011010110. Conveniently, the lowest place value is assigned to the first letter, A, because the lowest place value always exists, regardless of the size of the binary number or the block size. Within a block, the place values of the IR-absorbing letters are added together to obtain the total value of the represented binary number, which, according to this example, is 429. The previously mentioned sequence of digits in reverse order, 110101101 (i.e., with two leading ones), represents the standard binary representation with the most significant bit first. This binary number corresponds exactly to the value 429. The binary number has a reversed sequence of digits because, in binary numbers, the most significant bit is always given first. In this way, any information can be stored with the described security feature, for example, in the form of ASCII codes for any sequence of characters.

The 7 and 8 Figure 1 shows another embodiment of the security label 10 in a schematic top view. The print 11 again comprises K elements and CMY elements, which interact when printed side by side. The print 11 can include a list of ingredients and/or a manufacturer's address, with certain characters being designed as K elements and others as CMY elements. 7 Security label 10 is shown again in a representation intended to depict a view in the visible spectral range. 8 The security label shows 10 after 7 in a representation intended to depict viewing in the non-visible infrared spectral range. For example, in print 11, the letters of the word "Original" are not connected but spaced apart, so that these letters are printed as K elements and the remaining letters, numbers, or characters as CMY elements. When viewed in the visible spectral range (see... 7 ) it then appears as if simply an address or a table of contents is printed on it. When viewed in the invisible infrared spectral range (see... 8 The word "Original" then remains, so that the authenticity of the marked item can be verified easily and cost-effectively using the security feature. This could, for example, apply to a pharmaceutical container 2 to which the security label 10 is affixed (see figure). 9 ).

The 10 to 13 schematically show printing processes or setting variants for creating the security printing on the security label 10. 10 schematically illustrates that the three colored printing process colors are cyan (C), magenta (M), and Yellow and Y should preferably be aligned to each other to create a reliable security print. For this purpose, a registration pattern deviation can be checked and corrected if necessary in an inkjet printer. For example, cyan (C), one of the three colored inkjet process colors, is printed as a reference in the form of a one-pixel-wide line. Then, similar one-pixel-wide lines are printed above and below it using the other two inkjet process colors, magenta (M) and yellow (Y). 10 It is indicated that the printing inks Cyan (C), Magenta (M), and Yellow (Y) are not optimally aligned and are laterally shifted relative to each other. If the printing of the colored inkjet process colors is therefore not correctly aligned, this will be noticeable in the printed image because the yellow and magenta lines no longer coincide with the cyan reference line at position 0 in the print template, but are shifted to the right or left according to the misalignment. This can be corrected in the printing device so that the printing inks Cyan (C), Magenta (M), and Yellow (Y) are on a single line. Consequently, the CMY element can be produced with a particularly clean and perfectly aligned edge of the printing inks Cyan (C), Magenta (M), and Yellow (Y).

The 11 and 12 Figure 1 schematically shows how the security feature or security print can be applied to label layer 13. P1 represents a first print, which is set up to form the K-element. This can be done, for example, according to... 11 The security marking can be applied in a separate printing process based on conventional printing, such as flexographic or screen printing. In a second printing process, P2, the CMY element is created using the process colors cyan (C), magenta (M), and yellow (Y) via digital printing, such as inkjet, laser, electrostatic, and/or thermal printing. Security marking can therefore be applied using a hybrid printing process that combines conventional and digital printing. During digital printing, the CMY elements to be printed can be serialized and easily modified with regard to their printed image.

In 12 It is indicated that the first print P1 and the second print P2 can be executed as pure digital printing. Accordingly, the K elements and the CMY elements can be serialized and easily modified with regard to their printed image. With regard to underprinting according to the 3-4 is then the in 12 The illustrated print sequence must be taken into account so that the printhead or printing unit for black (K) is printed before the printing unit for cyan (C), magenta (M), and yellow (Y). If the K elements and the CMY elements are printed side by side, as shown in the 1-2 and 7-8 As shown, both the K elements and the CMY elements can be serialized. Accordingly, no change in the printing sequence is required. The security feature in the form of imprint 11 can therefore be produced exclusively using digital printing, so no additional production effort is incurred. If the K elements are to be covered or overprinted with corresponding CMY elements, a different printing sequence than usual must be considered in pure digital printing, but such a configuration enables the serialization of the security imprint with the IR-absorbing K elements under the IR-transparent CMY elements.

13 Figure 20 shows a schematic representation of the Lab color space to illustrate the targeted definition of the color coordinates of the CMY element. In Lab color space 20, the color values a and b are plotted against each other. The gray point 21, which represents the origin of the coordinate system (a=0 and b=0), is indicated in the center. Green (G) is positioned at the left end of the a-axis (a=-128). Red (R) is positioned at the right end of the a-axis (a=+127). Yellow (Y) is positioned at the top of the b-axis (b=+127). Blue (B) is positioned at the bottom of the b-axis (b=-128).

When the CMY element interacts with the K element, especially when they are to be printed side by side, it is beneficial to align and adjust the color and brightness appearance of the CMY and K elements to ensure that any difference between the two variants is not visually apparent. This alignment of the color coordinates of the CMY and K elements can be achieved through testing. For example, two black areas—one K area and one CMY area—can be printed on the same layer and compared. The K area, for instance, could have a brightness or luminance of L=4.1 and color coordinates of a=-2.7 and b=0.3 in the Lab color space. The CMY area, for example, with all three process colors at maximum printing intensity in the Lab color space 20, has a brightness or luminance L=10.6 and color coordinates a=-15.6 and b=4.1.

Accordingly, in a next step, the printing properties of the colors of the CMY element and/or the printing properties of the printing color of the K element can be adjusted to shape the black area. The goal is to print the CMY composite ink in such a way that its appearance is as identical as possible to that of the inkjet process color K. This can be achieved by adjusting the print density or the mixing ratio of the CMY components. In the present example, the color coordinates for the CMY black area with a = -15.6 and b = 4.1 are located in the upper left corner of the Lab color space 20 relative to the centrally located gray point 21. Therefore, it is beneficial to reduce both the cyan component (C) and the yellow component (Y) appropriately to shift the color coordinates of the CMY area closer to those of the K area with a = -2.7 and b = 0.3. Reducing the cyan component corresponds to a color shift to the upper right and lower right in the Lab color space 20. Reducing the yellow component corresponds to a color shift downwards in the Lab color space 20. Reducing the magenta component corresponds to a leftward color shift in Lab color space 20. Therefore, a shift of the color position of the CMY component by Δa = (-2.7) - (-15.6) = +11.9 and Δb = 0.3 - (+4.1) = -3.8 can be established. This color shift points downwards and to the right in Lab color space 20. Adjusting the L-value can be achieved, for example, by modifying the droplet size and/or droplet density of the K-element.

The 14 shows a flowchart for a process for forming a security print, for example on label layer 13.

In step S1, a starting label or a label blank with the label layer 13 is provided. Furthermore, one or more printing devices are provided, which have corresponding printing inks to form the K element and the CMY element in the form of the print 11.

In step S2, the security printing is formed by applying the printing 11 to the label layer 13. The printing 11 comprises at least one CMY element, which is formed by printing from a predefined composition consisting solely of the printing inks cyan (C), magenta (M), and yellow (Y) with a predefined print density, predefined mixing ratio, and predefined color position, such that it is perceived as black in the spectral range visible to the human eye and transparent in a spectral range invisible to the human eye, in particular the infrared spectral range.

In step S3, the K element is created by printing a character or string from the black ink K, either conventionally or digitally, so that it is perceived as black in the spectral range visible to the human eye and is absorbent in the spectral range invisible to the human eye. The sequence of steps S2 and S3 is not mandatory. If the K element is to be hidden beneath the CMY element, the creation of the K element must be performed before the CMY element.

In addition to steps S1-S3, one or more adjustment steps can be performed, as indicated by the optional step S4. This can involve aligning the colored printing inks cyan (C), magenta (M), and yellow (Y) according to... 10 include and/or an adjustment of the color coordinates a and b and/or the brightness L according to 13 The sequence of steps S1-S4 must then be adjusted accordingly, so that an adjustment according to step S4 is usually made before forming the final K element and the CMY element according to steps S2 and S3.

Reference symbol list

1

system

2

Object / Vessel

3

Vessel closure

4

Vascular bodies

10

Item / Security Label

11

Oppression

13

Label layer

20

schematic Lab color space

21

Grey point

B

Blue

C

Cyan

G

Green

K

Black

M

magenta

P1

first printing

P2

second print

R

Red

Y

Yellow

S(i)

Steps of a procedure for forming a security label

Claims (19)

Article (2, 10) with a security imprint, wherein the security imprint comprises an imprint (11) which is applied to the article (2, 10) is arranged or formed and which has at least one CMY element formed by printing from a predetermined composition consisting solely of the printing inks cyan (C), magenta (M) and yellow (Y) with a predetermined printing density, predetermined mixing quantity and predetermined color position, such that it is perceived as black or dark in the spectral range visible to the human eye and is configured to be transparent in a spectral range not visible to the human eye, wherein the CMY element interacts with another element which is arranged on or formed with the object (2, 10) and which is perceptible in the spectral range visible to the human eye and is configured to be absorbent in the predetermined non-visible spectral range. Subject (2, 10) according to Claim 1 , in which the CMY element is set to be transparent in an infrared and/or ultraviolet spectral range that is not visible to the human eye. Object (2, 10) according to one of the preceding claims, wherein the printing (11) comprises a K-element which provides the further element and which is formed from the printing ink black (K) such that it is perceived as black in the spectral range visible to the human eye and is configured to be absorbent in the spectral range not visible to the human eye, wherein a color appearance and/or brightness appearance of the CMY element and the K-element in the visible spectral range are arranged to be coordinated with each other. Subject (2, 10) according to Claim 3 , in which, with reference to a given color space, a CMY color point is assigned to the CMY element and a K color point is assigned to the K element, wherein a mixing ratio of the composition of the printing inks cyan (C), magenta (M) and yellow (Y) of the CMY element is specified such that the CMY color point and the K color point coincide within a given tolerance range. Subject (2, 10) according to Claim 3 or 4 , in which, with reference to a given color space, a CMY color location is assigned to the CMY element and a K color location is assigned to the K element, wherein a droplet size and/or a droplet density of the printing ink black (K) of the K element is specified such that the CMY color location and the K color location coincide within a given tolerance range. Item (2, 10) according to one of the Claims 3 until 5 , in which, with reference to a viewing direction towards the object (2, 10), the K element is formed below the CMY element. Item (2, 10) according to one of the Claims 3 until 6 , in which, with reference to a viewing direction towards the object (2, 10), the K element and the CMY element are formed next to each other and establish a common printing (11). Object (2, 10) according to one of the preceding claims, wherein, with respect to a viewing direction on the object (2, 10), the printing inks cyan (C), magenta (M) and yellow (Y) of the CMY element are aligned relative to each other and printed on top of each other and have a registration structure deviation of one pixel or less. Subject matter according to one of the preceding claims, wherein the security printing is designed as a pure digital print with a predetermined printing sequence of the printing inks black (K), cyan (C), magenta (M) and yellow (Y). Article according to one of the preceding claims, wherein the article is designed as a security label (10) and has a label layer (13) on which the security printing is formed. Subject according to Claim 10 , in which the CMY element is designed to be proportionally spaced apart from each other so that the portions of the CMY element act together as a common CMY element after the security label (10) has been applied to a substrate in accordance with operational procedures. System (1), comprising: - a vessel (2) with a vessel closure (3) and a vessel body (4), and - an object according to Claim 10 or 11 , which is arranged on the vessel (2). Method for forming a security imprint on an object (2, 10) according to one of the Claims 1 until 11 , comprising: - providing the object (2, 10), and - forming the security imprint on the object (2, 10) by applying a print (11), wherein the print (11) has at least one CMY element which is formed by printing from a predetermined composition consisting solely of the printing inks cyan (C), magenta (M) and yellow (Y) with a predetermined print density, predetermined mixing ratio and predetermined color position, such that it is perceived as black or dark in the spectral range visible to the human eye and is transparent in a spectral range not visible to the human eye, wherein the CMY element ment interacts with another element that is arranged on or formed with the object (2, 10) and that is perceptible in the spectral range visible to the human eye and is configured to absorb in the specified non-visible spectral range. Procedure according to Claim 13 , where the formation of the security printing includes: forming the CMY element with a predetermined composition consisting solely of the printing inks cyan (C), magenta (M) and yellow (Y), such that it is set up to be transparent in an infrared and/or ultraviolet spectral range that is not visible to the human eye. Procedure according to Claim 13 or 14 , in which the formation of the security printing comprises: forming the printing (11) with a K element that sets up the further element and which is formed from the printing ink black (K) so that it is perceived as black in the spectral range visible to the human eye and is set up to be absorbing in the spectral range not visible to the human eye, wherein a color appearance and/or brightness appearance of the CMY element and the K element are set up to be coordinated with each other. Procedure according to Claim 15 , in which the formation of the security printing includes: - Determining a color location of the K-element in relation to a specified color space, and - Adjusting a mixing ratio of the composition of the printing inks cyan (C), magenta (M) and yellow (Y) for the CMY element depending on the determined color location of the K-element, so that a color location of the CMY element and the color location of the K-element match within a specified tolerance range. Procedure according to Claim 15 or 16 , in which the formation of the security printing includes: - Determining a color location of the CMY element based on a specified color space, and - Adjusting a droplet size and/or a droplet density of the printing ink black (K) for the K element depending on the determined color location of the CMY element, so that the color location of the CMY element and a color location of the K element match within a specified tolerance range. Procedure according to one of the claims Claim 15 until 17 , in which the formation of the security printing comprises: - forming the K element by printing with the printing ink black (K), and subsequently - forming the CMY element by printing with the printing inks cyan (C), magenta (M) and yellow (Y), so that with respect to a viewing direction on the object (2, 10) the K element is formed below the CMY element. Procedure according to one of the claims Claim 15 until 18 , in which the formation of the security printing includes: - Determining a registration structure accuracy of the printing inks cyan (C), magenta (M) and yellow (Y) relative to each other, - Aligning the respective printing position of the printing inks cyan (C), magenta (M) and yellow (Y) depending on the determined registration structure accuracy, and - Forming the CMY element by printing with the aligned printing inks cyan (C), magenta (M) and yellow (Y) so that when printed on top of each other they have a registration structure deviation of one pixel or less.