EP2868483A1 - Method for making a security element - Google Patents

Abstract

The invention relates to a method for producing a security element (12) for security papers, value documents and other data carriers, in which a substrate (20) is provided with at least two visually distinguishable color areas (12A, 12B) by means of a first screen-printing cylinder (31), the substrate (20) is provided by means of a second screen-printing cylinder (32) with at least one third color region (12C) visually distinguishable from the at least two other color regions, - Wherein the color areas (12A, 12B, 12C) by means of first and second screen printing cylinder (31, 32) are applied in a printing pass and with a positional accuracy of less than 0.3 mm relative to each other on the substrate (20).

Description

The invention relates to a method for producing a security element for security papers, value documents and other data carriers. The invention also relates to a security element, which is produced by such a method, a data carrier, in particular a security paper or a valuable article, with such a security element and a device for carrying out said method.

Data carriers, such as Value documents have long been provided with colored imprints. The imprint takes place depending on the value document with suitable printing methods. In the past, in addition to the intaglio printing process, the offset printing process and the screen printing process have proven themselves for the mass production of documents of value and, in particular, of banknotes.

The screen printing process is a printing process in which the ink is transferred with a doctor blade through a fine-meshed fabric (screen) through the material to be printed. The sieve can be clamped on a cylindrical frame. It is then spoken of a so-called screen-printing cylinder.

A disadvantage of the value documents printed by such screen printing methods is, in particular, the fact that the motifs that can be displayed on the value document with only one screen printing ink do not offer any good protection against counterfeiting or imitation.

Proceeding from this, the object of the invention is an advantageous method for producing a security element of the aforementioned Specify type and avoid the disadvantages of the prior art.

This object is solved by the features of the independent claims. Further developments of the invention are the subject of the dependent claims.

• ein Substrat mittels eines ersten Siebdruckzylinders mit wenigstens zwei visuell unterscheidbaren Farbbereichen versehen wird,
• das Substrat mittels eines zweiten Siebdruckzylinders mit wenigstens einem dritten, von den
• wenigstens zwei anderen Farbbereichen visuell unterscheidbaren Farbbereich versehen wird,
• wobei die Farbbereiche mittels erstem und zweitem Siebdruckzylinder in einem Druckgang und mit einer Positionsgenauigkeit von kleiner 0,3 mm relativ zueinander auf dem Substrat aufgebracht werden.

According to the invention, in a method for producing a security element for security papers, value documents and other data carriers, it is provided that

• a substrate is provided with at least two visually distinguishable color areas by means of a first screen-printing cylinder,
• the substrate by means of a second screen printing cylinder with at least a third, of the
• providing at least two other color areas visually distinguishable color range,
• wherein the color areas are applied by means of first and second screen printing cylinder in a printing pass and with a positional accuracy of less than 0.3 mm relative to each other on the substrate.

The method according to the invention therefore provides for applying at least two and, by means of a second screen-printing cylinder, at least one third color area on the substrate to be printed by means of a first screen-printing cylinder.

As will be explained in more detail below, the application of the color areas on the substrate in a printing pass, i. The substrate to be printed is provided in a suitable device in the region of a so-called impression cylinder first with the provided by the first screen printing cylinder and visually distinguishable screen inks and immediately thereafter with the at least one further and provided by the second screen printing cylinder screen printing ink. Between the application of the screen printing inks of the first screen printing cylinder and the at least one further screen printing ink of the second screen printing cylinder, the substrate is thus not removed from the device, so that with a correspondingly precise positioning of the two screen printing cylinders relative to each other and the color regions applied to the substrate a very high positional accuracy relative to each other. In contrast to the screen printing methods known from the prior art in which a plurality of screen printing inks are applied to the substrate in a plurality of printing passes, the inventive method substantially increases the positional accuracy of the screen printing inks on the substrate. Also, the inventive method is much more economical than the application of multiple color areas in several printing passes, because this is required for each printing a screen printing machine with a Siebdruck- and impression cylinder.

The achieved with the inventive method position accuracy of the color ranges relative to each other of less than 0.3 mm means over the prior art much better protection against forgery provided with a security element according to the invention value document because such a high positional accuracy of screen-applied color ranges of a counterfeiter with simple means can not be adjusted. In addition to the increased protection against counterfeiting due to the high positional accuracy the color ranges relative to each other, the inventive method also has the advantage over the counterfeit protection by the fact that very complex multicolor motifs can be applied by screen printing. Such complex multicolor motifs, which are produced by means of screen printing technology, also present the counterfeiter with insurmountable hurdles, so that the counterfeit protection of the value document is also increased by this measure. Apart from that, multi-color motifs have a very high recognition value among the users of the value documents, in particular the banknotes, which as a result also improves the counterfeit protection of the respective value document.

The color areas applied to the substrate by means of the method according to the invention are visually distinguishable. In the context of the present invention, two color regions are considered to be visually distinguishable if and only if at least one optical property of the two color regions is different in the visible wavelength range. It is understood that the visual distinctiveness depends strongly on the respective observer and his subjective perception of the color areas. Therefore, in the context of the present invention, two color areas are understood to be visually distinguishable if and only if they are formed by printing inks having different optical properties in the visible wavelength range. The different optical properties of the color areas must be given after application to the substrate and, if appropriate, after carrying out suitable process steps, such as the drying of the color areas, and be measurable using suitable measuring methods, suitable measuring methods for measuring the optical properties being known to the person skilled in the art. The visible wavelength range extends in the context of the present invention from about 380 nm to about 780 nm.

For various reasons, the color regions may have different optical properties in the visible wavelength range. The optical properties of a color range are understood to be, in particular, the properties of a color perceived by humans as fundamental, namely hue, brightness and color saturation. The quality of the color effect on a viewer of a color range can also be described by values such as chroma, color (color intensity), chromaticity, color depth, brilliance and gray tone. Furthermore, the color ranges of the security elements and data carriers according to the invention can also be characterized by further optical properties, e.g. by their reflectivity.

It should also be noted that two color regions that are visually distinguishable according to the definition given above need not differ over the entire visible wavelength range from about 380 nm to about 780 nm with respect to an optical property. Rather, the two color regions at a first wavelength in the visible wavelength range may differ with respect to a first optical property and at a second wavelength different from the first wavelength may differ in a second optical property different from the first optical property. It is also conceivable that changing the viewing angle between a color area and the viewer produces a change in the optical properties of the color area. This is the case, for example, with security elements or data carriers according to the invention having a color range which is optically variable. That is to say, one of the above-mentioned optical properties, in particular the hue, the brightness, the color saturation or the reflectivity of the considered color range, changes in the visible wavelength range with the viewing angle. For two according to the invention visually distinguishable It is therefore possible for color areas to differ with respect to a first optical property at a first viewing angle and with respect to a second optical property at a second viewing angle.

As a result, therefore, two color regions in the context of the present invention are precisely visually distinguishable if they differ in at least one wavelength in the abovementioned visible wavelength range from about 380 nm to about 780 nm in at least one optical property.

As for the positional accuracy of the color ranges of smaller than 0.3 mm in the relative to each other on the substrate, the measurement of this positional accuracy will be explained in detail below with reference to the figures.

According to a preferred variant of the method, the substrate is provided by means of the first screen-printing cylinder with two visually distinguishable color areas and by means of the second screen-printing cylinder with two further color areas visually distinguishable from the first two color areas. That is, with the first screen-printing cylinder two and with the second screen-printing cylinder two further distinct color ranges are applied to the substrate, so that a total of four distinguishable color ranges are present on the substrate. It has been found that by means of four visually distinguishable color areas, extremely complex motifs can already be produced which, for the counterfeiter, can not be imitated relative to one another in view of the high position accuracy of the color areas. In addition, motifs and representations of four colors for a viewer of the subject or the designated have Data carrier a very high recognition value, which also leads to an increase in counterfeit security. Incidentally, the method according to the invention with two screen printing cylinders and in each case two color areas applied to the screen printing cylinders on the substrate can be economically advantageous, ie cost-effective, with only one device according to the invention.

The visually distinguishable color regions can advantageously be applied to one another in precise position adjacent to one another on the substrate, which makes possible the production of a multiplicity of very different and at the same time very tamper-proof security elements.

In order to further increase the security against counterfeiting, provision may also be made for at least one color area to be applied in exact position at least partially over another color area. In such a case, the at least partially superposed arrangement of the color regions makes the viewer of an overlapping region aware of a mixed color which, with suitable selection of the screen printing inks provided for the overlapping color regions, can not or only to a very limited extent be produced by a single color. These embodiments are characterized by high counterfeit security and a very high recognition value.

When applying the color areas and in particular when applying a color area at least partially over another color area, it is preferred to dry or harden at least one of the color areas at least partially with a drying device. By (partial) drying in particular screen printing inks with low viscosity can be applied to the substrate better and contour sharper.

Also, a second screen printing ink to be arranged above this screen printing ink can be applied with a sharper contour. The contour sharpness together with the positionally accurate application of the color areas is an essential prerequisite for the production of a particularly tamper-proof security element according to the present invention.

Further, it is preferred if at least one color region with a layer thickness is applied to the substrate, which differs from the layer thickness of the other color regions. The layer thickness of a color area is determined in particular by the mesh width present in the screen of the screen printing cylinder. If the layer thicknesses of two color areas differ sufficiently strongly, then the two color areas can also be distinguished by a viewer by feeling, which represents a further security feature for the security elements or data carriers according to the invention provided with the color areas. Incidentally, in providing a screen having two different mesh sizes, it is possible to apply colors having large pigment particle sizes and high layer thicknesses as well as colors having small pigment particle sizes and small layer thicknesses to the substrate with only one screen, which is particularly economical.

In a particularly advantageous variant of the method, the color regions are applied relative to each other with a positional accuracy of less than 0.2 mm and preferably of less than 0.1 mm on the substrate. Such an extremely high position accuracy of the color areas relative to each other presents the counterfeiter with insurmountable obstacles. In addition, even very complex subjects with such a high position accuracy of the color ranges can be made relative to each other, that the viewer the subject and thus secured disk readily recognizes, which also increases the counterfeit security for the disk as a result.

• ein Substrat, das mit wenigstens drei visuell unterscheidbaren Farbbereichen versehen ist,
• wobei wenigstens zwei Farbbereiche mittels eines ersten und wenigstens ein dritter Farbbereich mittels eines zweiten Siebdruckzylinders in einem Druckgang und mit einer Positionsgenauigkeit von kleiner 0,3 mm relativ zueinander auf dem Substrat aufgebracht sind.

The invention also includes a security element for securing security papers, documents of value and other data carriers, which is produced by the method described above. The security element contains

• a substrate provided with at least three visually distinguishable color areas,
• wherein at least two color areas are applied by means of a first and at least one third color area by means of a second screen printing cylinder in a printing pass and with a positional accuracy of less than 0.3 mm relative to each other on the substrate.

In an advantageous development of the invention, the security element has four visually distinguishable color areas. As already mentioned, complex visuals with high recognition value and very high counterfeit protection can be produced with four visually distinguishable color areas.

Furthermore, a security element is preferred, in which the visually distinguishable color regions are arranged in exact position adjacent to one another on the substrate.

Alternatively, it is of course also conceivable that in the security element at least one color region is arranged with exact position and at least partially over another color region. As already mentioned, are the mixing colors that can be produced thereby are provided with a high recognition value for a viewer, and it is virtually impossible for a counterfeiter to reproduce a specific mixed color by means of only one printing ink.

The security element advantageously has at least one color region whose layer thickness differs from the layer thickness of the other color regions. Such a security element is tactile detectable with a sufficiently large layer thicknesses and a suitably high deviation of the layer thicknesses of the color regions among one another for a person.

In addition, a security element in which the color regions are arranged relative to one another with a positional accuracy of less than 0.2 mm and particularly preferably of less than 0.1 mm on the substrate is particularly preferred. Security elements with such a great position accuracy of the color regions relative to one another are advantageously extremely forgery-proof.

The invention further comprises a data carrier with a security element of the type described. The security element may be part of the data carrier by providing the substrate of the security element, or the security element may be applied with its substrate on a separate data carrier. The data carrier may in particular be a banknote, in particular a paper banknote, preferably a cotton paper banknote, a polymer banknote or a film-paper composite banknote. The latter preferably has a layer sequence foil / paper / foil or paper / foil / paper. The data carrier can also be an identification card, in particular a credit card, a Bank card, cash card, authorization card, identity card, passport or passport personalization page.

• einem ersten Siebdruckzylinder mit wenigstens zwei durch einen Trennbereich getrennten Siebbereichen zur Aufbringung zweier visuell unterscheidbarer Farbbereiche auf einem Substrat,
• einem zweiten Siebdruckzylinder mit wenigstens einem Siebbereich zur Aufbringung wenigstens eines dritten Farbbereichs auf dem Substrat,
• einem Gegendruckzylinder, und
• Mitteln zur Positionierung des ersten und zweiten Siebdruckzylinders relativ zueinander mit einer Positionsgenauigkeit von kleiner 0,3 mm.

Finally, the invention also encompasses a device for carrying out the method described

• a first screen-printing cylinder having at least two screen areas separated by a separation area for applying two visually distinguishable color areas on a substrate,
• a second screen-printing cylinder having at least one screen area for applying at least one third color area to the substrate,
• an impression cylinder, and
• Means for positioning the first and second screen printing cylinder relative to each other with a positional accuracy of less than 0.3 mm.

In this case, a device is preferred in which the separating region of the first screen-printing cylinder has a separating ring arranged in the interior of the screen-printing cylinder, in particular an elastic separating ring.

Advantageously, the separating ring has a width of less than 20 mm, preferably less than 15 mm. As a result, the width of the third color area applied to the substrate with the second screen-printing cylinder can be reduced to less than 20 mm, preferably less than 15 mm.

In a further preferred embodiment, it is provided that the first and / or second screen-printing cylinder has a screen with at least two different mesh sizes. This allows the generation at least two differently thick and visually distinguishable color areas with only one screen printing cylinder.

Furthermore, a device which has at least one drying device for at least partial drying of at least one color region is preferred, since in particular contour-sharper color regions can be produced on the substrate.

To produce the visually distinguishable color areas suitable screen printing inks are used. The screen printing inks advantageously contain dyes and pigments to produce a specific color. In particular, the screen printing inks comprise effect pigments, in particular pigments with an optically variable impression which depends on the viewing direction. These effect pigments are advantageously based on liquid crystalline polymers prepared pigments or so-called pearlescent pigments, such as those sold by the company Merck KGaA under the designation Iriodin ^® or Colorcrypt silver-white, gold luster or metal luster pigments. Both pigments based on liquid-crystalline material and pearlescent pigments are translucent on their own. In other, likewise advantageous embodiments of the invention, the first effect pigments are formed by interference layer pigments. Such interference layer pigments typically have a thin-film structure which expediently contains at least one reflection layer, one absorber layer and a dielectric spacer layer arranged between the reflection layer and the absorber layer. Interfacial layer pigments can be translucent per se, although opaque interference layer pigments are also known.

In the context of the present description, "translucent" means translucent in the sense of a certain or complete translucency and thus also includes transparency. A translucent layer makes it possible to perceive the objects behind or below it, even if the brightness of the objects can be reduced by the translucent layer and / or the color of the objects can be changed. On the other hand, if the light transmission of a layer is so low that the objects behind or underneath it are no longer recognizable, it is no longer translucent but is called opaque or opaque.

Further exemplary embodiments and advantages of the invention are explained below with reference to the figures, in the representation of which a representation true to scale and proportion has been dispensed with in order to increase the clarity.

Fig. 1

eine schematische Darstellung einer Banknote mit einem erfindungsgemäßen Sicherheitselement,

Fig. 2

das Sicherheitselement der Fig. 1 schematisch im Querschnitt entlang der Linie B-B in Fig.1,

Fig. 3

eine schematische Darstellung der erfindungsgemäßen Vorrichtung zur Erläuterung deren Arbeitsprinzips bei der Durchführung eines erfindungsgemäßen Verfahrens,

Fig. 4

eine Ausführungsform des erfindungsgemäßen Sicherheitselements in (a) Aufsicht und in (b) im Querschnitt entlang der Linie B-B,

Fig. 5

eine weitere Ausführungsform eines erfindungsgemäßen Sicherheitselements mit überlappenden Farbbereichen in (a) Aufsicht und in (b) im Querschnitt entlang der Linie B-B,

Fig. 6.

eine weitere Ausführungsform mit sich überlappenden Farbbereichen in einer Querschnittsdarstellung,

Fig. 7

eine schematische Darstellung eines im erfindungsgemäßen Verfahren eingesetzten Siebdruckzylinders mit zwei unterschiedlichen Maschenweiten, und

Fig. 8

eine Querschnittsdarstellung eines erfindungsgemäßen Sicherheitselements zur Erläuterung der Bestimmung der Positionsgenauigkeit der Farbbereiche relativ zueinander.

Show it:

Fig. 1

a schematic representation of a banknote with a security element according to the invention,

Fig. 2

the security element of Fig. 1 schematically in cross section along the line BB in Fig.1 .

Fig. 3

a schematic representation of the device according to the invention for explaining the working principle in carrying out a method according to the invention,

Fig. 4

an embodiment of the security element according to the invention in (a) top view and in (b) in cross section along the line BB,

Fig. 5

a further embodiment of a security element according to the invention with overlapping color regions in (a) top view and in (b) in cross section along the line BB,

Fig. 6.

a further embodiment with overlapping color areas in a cross-sectional representation,

Fig. 7

a schematic representation of a screen printing cylinder used in the process according to the invention with two different mesh sizes, and

Fig. 8

a cross-sectional view of a security element according to the invention for explaining the determination of the positional accuracy of the color regions relative to each other.

The invention will now be explained using the example of security elements for banknotes and other value documents. Fig.1 shows in plan a schematic representation of a banknote 10, which is provided with a security element 12 according to the invention. The security element 12 has three visually distinguishable color areas 12A, 12B and 12C, which are arranged in exact position adjacent to one another on the substrate 20. The color areas 12A, 12B and 12C are arranged in the lower region of the banknote 10 in the form of an elongate strip which extends substantially parallel to the long side 14, ie transversely to the short side 15 of the banknote 10. During the color range 12C as a full-surface screen printing layer is applied to the substrate 20, the color regions 12A and 12B each have a recess 18A and 18B in the color region, which in accordance with Fig.1 the denomination "100" corresponds to the banknote. Through the non-printed areas 18A and 18B, the viewer can recognize the bank note substrate 20 lying behind the color areas from its viewing direction. Since the banknote substrate has a much lighter color than the color areas 12A and 12B, the viewer can very well perceive the denomination "100" formed by the recesses 18A and 18B and otherwise compare it with the further denomination indication 19, which is produced, for example, by another printing method the substrate 20 has been printed.

To produce the color areas 12A, 12B and 12C, screen printing inks with optically variable pigments were used, the color areas visually differing from one another. This can be done, for example, by the screen printing inks used to produce the ink areas 12A, 12B and 12C comprising optically variable pigments which differ greatly in their color in a particular viewing direction. For example, it can act ^® pigments located in the pigments used in the printing ink of the color range 12A pearlescent pigments, in particular Iriodin that give the color area 12A in plan a green color, while the corresponding Iriodin ^® pigments in the areas 12B and 12C the color area give a red or blue color. Of course, it is also possible to use all the other screen printing inks, dyes and pigments mentioned above, in particular interference layer pigments, as long as they impart different colors and thus different optical properties to the color regions 12A to 12C at least for viewing from a viewing direction.

For further explanation shows Fig. 2 the security element 12 of Fig.1 schematically in cross section. On the paper substrate 20 of the banknote 10, the security element 12 is applied in the form of the three color areas 12A, 12B and 12C, wherein the color areas 12A, 12B and 12C are arranged relative to each other positionally accurate. That is, the color areas 12A to 12C do not overlap, but are, as in Fig. 2 shown abutting on the substrate 20 without impact from each other. It is understood that due to the viscosity of the screen printing inks required for application in screen printing, the color areas 12A to 12C have in practice not so sharply defined edges and not as uniform layer thicknesses as in US Pat Fig. 2 is shown in idealized form. However, the process parameters, in particular the viscosity of the screen printing inks must always be chosen so that a positional accuracy of the ink areas 12A to 12C relative to each other of less than 0.3 mm can be achieved.

If necessary, further layers, in particular dark color layers, can be arranged between the substrate 20 and the security element 12, which change the optical properties, in particular the color of the color regions 12A to 12C arranged above such layers and make them easier to detect for the viewer. Instead of such in Fig. 2 Not further illustrated layers, in particular printed layers, between substrate 20 and security element 12 may also be arranged, for example, film elements, in particular film elements with full-surface and / or partial metal coating. Also conceivable are elongated film elements, in particular security threads, which are arranged at least partially on the surface of the substrate 20 in the region of the security element 12. To simplify the illustration, the above-mentioned security threads or foil elements are in Fig. 2 not shown.

The manufacturing process will now be with reference to Fig. 3 explained in more detail, which schematically shows a device 30 according to the invention. The apparatus 30 comprises a first screen-printing cylinder 31 having a plurality of screen areas separated by separating areas for applying two visually distinguishable color areas to a substrate. In detail, the first screen-printing cylinder 31 has a screen with screen areas 33A and 33B, which are separated from one another by the separation areas 34. The separating regions 34 have separating rings 35, which are arranged in the interior of the screen-printing cylinder, for effective separation of the screen regions 33A, 33B of the screen-printing cylinder 31. In the present embodiment, the separating rings 35 are formed with a width of about 15 mm elastic, since they are essentially formed by an elastic plastic material. The screen 33 of the first screen printing cylinder 31 further comprises screen areas 2A and 2B, through which the screen printing ink for forming the color areas 12A and 12B on the substrate by means disposed in the interior of the screen printing cylinder and not further in the Fig. 3 is shown applied doctor blade. This is done by the substrate sheet 200 having a plurality of still to be separated banknotes 10 is passed between the screen printing cylinder 31 and the impression cylinder 38 and thereby with the pushed through the screen areas 2A and 2B and on the substrate with the reference numerals 12A and 12B designated color areas. In the present case, the screen-printing cylinder 31 has three pairs of screen areas 2A and 2B in a direction transverse to the transport direction 39 of the sheet 200, so that a total of three banknote substrates 20 are provided in a direction transverse to the transport direction 39 with the two visually distinguishable color areas 12A and 12B can. It is understood that this is a greatly simplified representation and the screen printing cylinder in practice for printing a much larger number of individual banknote substrates 20 in a direction transverse to the transport direction of the sheet 200 are designed. Also, it is understood that the screen printing cylinder in the transport direction 39 more in Fig. 3 For simplicity, not shown further Siebbereiche 2A and 2B, in order to apply in the transport direction 39 more color areas 12A and 12B on banknote substrates.

The inventive device 30 according to Fig. 3 further comprises the second screen printing cylinder 32, the screen 36 of which comprises screen areas 36C which enable the color areas 12C to be applied to the banknote substrate 20 by means of the screen areas 2C permeable to the screen printing ink. Also for the screen-printing cylinder 32, it is understood that in the transport direction 39 and transversely to the transport direction 39 of the substrate sheet 200 it has in practice a significantly larger number of screen areas 2C.

As Fig. 3 can be seen, the areas 2A and 2B or 2C of the first and second screen printing cylinder are arranged positionally accurate to each other, so that the application of the color regions 12A to 12C on the substrate 20 can also be done positionally accurate, as Fig.1 and Fig. 2 can be seen and based on Fig. 8 will be explained in more detail. The substrate sheet 200 having a multiplicity of individual banknote substrates 20 is passed according to the invention in a printing pass between the first screen-printing cylinder 31 and the impression cylinder 38 or between the second screen-printing cylinder 32 and the impression cylinder 38. The provision of means for positioning the first and second screen printing cylinders 31 and 32 relative to one another therefore enables the ink areas 12A to 12C to be arranged relative to each other on the substrate with a positional accuracy of less than 0.3 mm. In Fig. 3 the means for positioning the first and second screen printing cylinder are not shown for the sake of clarity. It may be, for example, a mechanical device act, which allows the screen printing cylinder 31 and 32 in the transport direction 39 and transversely to the transport direction 39 relative to each other and also positionally accurate with respect to the substrate sheet 200 to align.

Particularly in the case of the overlapping arrangement of color areas, the color areas first applied to the substrate are expediently dried or hardened at least partially by means of a drying apparatus. As a drying device, e.g. a UV lamp, an LED dryer or any alternative device can be used.

The inventive method using the device according to the invention is of course not limited to the generation of three visually distinguishable color areas 12A, 12B and 12C on a data carrier. In particular, it is readily possible in accordance with the embodiment Fig. 3 for the application of only one color region 12C per substrate 20 provided screen printing cylinder 32 to modify according to the screen printing cylinder 31 and to provide by providing separation areas, the application of two or more color areas. In particular, it is preferred for economic reasons to provide a device with two screen printing cylinders, wherein each screen printing cylinder is designed for applying two visually distinguishable color areas, so that four positionally precisely arranged and visually distinguishable color areas can be produced on a data carrier, in particular a banknote , With technically greater effort, in particular a larger number of screening areas and separation areas, in addition with two screen printing cylinders but also five, six or more color ranges can be applied positionally accurate to each other on a disk.

The inventive method is characterized for all variants by a very high production rate of about 8,000 to 10,000 substrate sheets per hour, which is an economic advantage of the invention.

In Fig. 4 a further embodiment of the security element according to the invention is shown. The security element 12 is four color areas 12A to 12D arranged in exactly the same position, each having the shape of an arrow and complementing one another to form an elongated and larger arrow, which corresponds, for example, to the security element in FIG Fig.1 essentially along the long side of a data carrier, in particular a banknote, may be arranged (see Fig. 4 (a) ). For the preparation of the security element 12 according to the embodiment according to Fig. 4 the method according to the invention was used on a device 30 according to the invention, wherein the first and second screen-printing cylinders 31 and 32 of the device (see Fig. 3 ) each having two separated by a separation region screen areas, so that by means of the first and second screen printing cylinders 31, 31 each two visually distinguishable color areas can be applied to the substrate. In particular, by means of the first in Fig. 3 shown screen printing cylinder 31, the color areas 12A and 12B applied and by means of the second screen printing cylinder 32, the color areas 12C and 12D. For example, the color areas 12A and 12B can have a yellow or red color, which is caused by a corresponding selection of dyes or pigments in the screen printing inks used to produce the area 12A and 12B. In a corresponding manner, to produce the color regions 12C and 12D, which have, for example, a blue or green color, screen printing inks with corresponding dyes or pigments are used.

As the cross-sectional view according to Fig. 4 (b) can be removed, the layer thicknesses of the four color regions differ from each other, which is caused in particular by the provision of different mesh sizes in the first and second screen printing cylinder. In the illustrated embodiment, the ink areas 12A and 12B are formed by a first screen printing cylinder 31 having screen areas 2A and 2B, the mesh width of the area 2A being 180 mesh and the area 2B being 230 mesh. The mesh size is given in the context of the present invention in the widespread in the screen printing Anglo-American unit of measurement "mesh". A value of 180 mesh corresponds to a screen with 180 meshes per inch (25.4 mm).

It should be mentioned at this point that the mesh size only corresponds approximately to the layer thickness that can be achieved on the substrate, since the screen meshes are usually additionally calendered and provided with a galvanic layer. Thus, under certain circumstances, even with screens of the same mesh count, at least to a certain extent different layer thicknesses of the color areas can be produced on the substrate.

Accordingly, the ink areas 12C and 12D were formed with a second screen cylinder having 275 mesh and 165 mesh mesh areas 2C and 2D, respectively. Thus, for example, screen printing inks with large pigment particle sizes and large layer thicknesses, and visually distinguishable screen printing inks with smaller pigment particle sizes and smaller layer thicknesses on the substrate, can be produced with a screen-printing cylinder. The security element 12 with accurately positioned color regions 12A, 12C, 12B and 12D is tactile detectable for the user and due to the provision of four visually distinguishable due to the different layer thicknesses of the color regions dA, dC, dB and dD Colors are also equipped with a high recognition value for the viewer. The tactile detectable color ranges are thus suitable, for example, with a layer thickness of typically up to 120 μm, in order to produce braille (Braille) on the data carrier to be secured with the security element. Due to the inventive positionally accurate arrangement of the color areas is in Fig. 4 shown security element 12 thus characterized by a very high security against counterfeiting. It should be noted that the security element 12 of Fig. 4 nor that in color areas with a relatively large area and the associated relatively high consumption of screen printing inks, at least for the large color areas inexpensive screen printing inks of similar color can be used, and for the color areas with smaller area more expensive screen printing inks can be used. It is known that screen printing inks with effect pigments with, for example, a three-layer thin-film structure and effect pigments with a multilayer thin-film structure and at least one magnetic layer are relatively expensive. On the one hand, it is possible to magnetically align the thin-film pigments with an additional magnetic layer by means of a suitable magnetization unit for generating three-dimensionally acting motifs before the curing of the screen printing ink and to generate an additional security feature. However, these effect pigments are very expensive, so that the use of color ranges of similar color, but lower material costs, as is the case for example with screen printing inks with Iriodinen ^® offers.

In addition, it is possible accordingly Fig. 4 (a) provide four color areas, which have further safety-relevant properties by using suitable feature substances. For example, the color areas 12A to 12D may comprise, as additional feature substances, thermochromic materials which change color at a certain triggering temperature.

Thus, the color areas 12A, 12C, 12B and 12D of the Fig. 4 (a) For example, thermochromic materials having a triggering temperature of, for example, 18 ° C, 25 ° C, 30 ° C and 35 ° C and thus a security element are provided, which in addition to the advantages already explained by a viewer can also be recognized particularly well, because the four color areas at different trigger temperatures change their color. The very high recognition value of such a security element contributes to an extremely large protection against counterfeiting of the security element and the data carrier marked with it.

The additional security features provided in the color areas may, in addition to the above-described magnetic and thermochromic materials, e.g. also in the form of fluorescent visible in the visible or non-visible wavelength range materials. Furthermore, the color regions may contain microcapsules which have alignable magnetic pigments by means of an external magnetic field. For example, the magnetic field of the permanent magnet of a portable audio player, mobile phone or goods security system can be used to align the magnetic pigments in the microcapsules and thus cause a certain, predetermined change in the optical properties of the color region having these microcapsules, so that another security feature for verification of the security element.

In Fig. 5 a further embodiment of the security elements according to the invention is shown. This in Fig. 5 (a) The security element 50 shown in plan view includes the color areas 52A to 52D. The colors of the color areas 52A to 52D are visually different from each other, with the color areas 52A and 52B being defined by a first screen printing cylinder and the color areas 52C and 52D were applied to the substrate 54 by a second screen printing cylinder. In contrast to the previously described embodiments are in the embodiment according to Fig. 5 not all color areas exactly next to each other, but also partially arranged one above the other. While the color areas 52A, 52C and 52B are arranged positionally exactly next to one another, the color area 52D is positioned exactly above the color area 52A or 52B. This is possible in the above-described use of two screen printing cylinders and leads to the in Fig. 5 (b) If the screen printing inks provided for producing the ink areas 52A to 52C have a relatively low viscosity, the ink areas 52A to 52C applied to the substrate are at least partially dried by means of a dryer before the color area 52D is over the color area 52A and 52B, respectively. This can be one in the description too Fig. 3 mentioned drying device can be used.

An observer viewing the security element 50 in a top view can perceive a mixed color in the area where the color area 52D is located above the color areas 52A and 52B, respectively, because the screen ink used for the color area 52D is sufficiently translucent, to make the colors of the color areas 52A and 52B recognizable as mixed colors for the viewer. As a result, in the region of the color region 52D, the viewer thus sees the mixed colors resulting from the inherent colors of the regions 52D and 52A, and 52D and 52B. These mixed colors perceivable by the viewer give the security element 50 a very high recognition value and, moreover, enable the production of very complex multicolored motifs, which represent an almost insurmountable obstacle for a counterfeiter. An increase in complexity results for the in Fig. 5 Moreover, the embodiment shown in FIG. 8 also has the color areas 52D arranged above the color areas 52A and 52B having different colors. The areas 52C and the in Fig. 5 two color areas 52D shown then have three different colors, so that the viewer in the provision of translucent screen inks for the areas 52D again perceives corresponding mixed colors. On the other hand, if two different and opaque colors are used for the color areas 52D, the observer can only perceive their own color for the color areas 52D. In any case, the arrangement of color areas over other color areas allows the creation of multi-colored motifs with large layer thicknesses and associated good tactile detectability.

A still further embodiment of the security element according to the invention is in Fig. 6 shown in cross section. In this case, the security element 60 comprises the color areas 62A to 62D arranged with exact position on the substrate 64. In this case, the color areas 62A, 62B and 62C are applied by means of a first screen-printing cylinder, while the color areas 62D and 62E are applied by means of the second screen-printing cylinder. The color areas 62A and 62C may have the same or a different intrinsic color. In a corresponding manner, the color areas 62D and 62E applied with a translucent color can be of the same color or different colors. Also in this embodiment, the color areas are arranged relative to each other positionally exactly next to each other and partly on top of each other. As Fig. 6 As can be seen, the color regions 62A and 62C have a smaller layer thickness dA and dC on the substrate 64, while the color regions 62D, 62E and 62B have a significantly greater layer thickness dD, dE and dB. The security element 60 is thus an extremely tamper-proof security element, what about it In addition, due to the multicolor for the viewer has a great recognition value, which also contributes to the protection against counterfeiting of the security element or the marked with the security element data carrier.

In Fig. 7 There is shown a screen printing cylinder 70 having a screen with screen areas 71A and 71B separated by the schematically illustrated separation areas 74. The screen areas 71 A have the required for the passage of a screen printing ink screen areas 2A with a first mesh size of eg 180 mesh. In a corresponding manner, the screen areas 71B for the passage of the second screen printing ink have a screen area 2B with a mesh width of, for example, 230 mesh. Alternatively, the screen areas 2A could have a mesh size of eg 275 mesh and the screen areas 2B could have a mesh size of eg 165 mesh. A screen printing cylinder with mesh sizes 180 mesh and 230 mesh could thus be used to produce the color areas 12A and 12B in FIG Fig. 4 while a 275 mesh and 165 mesh screen printing cylinder is used in the screen areas 2A and 2B to form the color areas 12C and 12D of the embodiment of FIG Fig. 4 could be used. Although the provision of two screen areas with different mesh size per screen printing cylinder is economically particularly interesting, it is of course also possible to provide a screen printing cylinder with three or four screen areas, each with different mesh size, so as in the manner described above, three or four visually distinguishable color areas of different layer thickness position accurate on a substrate.

The screen printing inks used in the present invention contain in addition to the components typically used for screen printing inks a proportion of about 15 wt .-% to 25 wt .-% of dyes or pigments.

A method of determining the positional accuracy of the color areas relative to each other will now be described Fig. 8 explained.

The security element according to Fig. 8 points according to the security element of Fig. 2 three color areas 12A to 12C, which in the Fig. 3 explained method of the invention were applied in a printing pass on the substrate 20. In order to determine the positional accuracy of the color regions, the regions in which the color regions 12A and 12C as well as 12C and 12B, ideally adjoin one another in an abutting manner, have now been examined in more detail by means of microscope images not shown here. How out Fig. 8 is shown schematically, results for the region 16, a small overlap D1 of the color regions 12A and 12C, while the region 17 has a pressure-free region D2 between the color regions 12C and 12B. The amount of the overlap D1 of the color areas 12A and 12C in the area 16 and the amount of the distance D2 of the color areas 12C and 12B in the area 17 are measured by means of microscope images. If the measured value for the amount of overlap or the distance is below 0.3 mm, the feature of the positionally accurate arrangement of the color ranges for the measured security element is fulfilled. The color areas are then applied with a positional accuracy of less than 0.3 mm relative to each other on the substrate.

How out Fig. 8 It can also be seen that the layer thickness of the screen printing layer in the region of the overlap 16 is higher by the amount d1 than in the region of the non-overlapping color regions 12A to 12C, where the layer thickness in each case has the value d.

Claims (18)

Method for producing a security element for security papers, value documents and other data carriers, in which a substrate is provided with at least two visually distinguishable color areas by means of a first screen-printing cylinder, the substrate is provided by means of a second screen-printing cylinder with at least a third color region visually distinguishable from the at least two other color regions, - Wherein the color areas are applied by means of first and second screen printing cylinder in a printing pass and with a positional accuracy of less than 0.3 mm relative to each other on the substrate. A method according to claim 1, characterized in that the substrate is provided by means of the first screen printing cylinder with two visually distinguishable color areas and by means of the second screen printing cylinder with two further color regions visually distinguishable from the first two color areas. A method according to claim 1 or 2, characterized in that the visually distinguishable color regions are applied positionally exactly adjacent to each other on the substrate. A method according to at least one of claims 1 to 3, characterized in that at least one color range is applied positionally accurate and at least partially over another color range. Method according to at least one of claims 1 to 4, characterized in that at least one color region with a layer thickness is applied to the substrate, which differs from the layer thickness of the other color ranges. Method according to at least one of claims 1 to 5, characterized in that the color regions are applied relative to each other with a position accuracy of less than 0.2 mm, preferably of less than 0.1 mm on the substrate. Security element for securing security papers, documents of value and other data carriers, produced according to one of claims 1 to 6, with, a substrate provided with at least three visually distinguishable color areas, - Wherein at least two color areas are applied by means of a first and at least a third color range by means of a second screen printing cylinder in a printing pass and with a positional accuracy of less than 0.3 mm relative to each other on the substrate. Security element according to claim 7, characterized in that it has four visually distinguishable color areas. A security element according to claim 7 or 8, characterized in that the visually distinguishable color areas are arranged in exact position adjacent to each other on the substrate. A security element according to at least one of claims 7 to 9, characterized in that at least one color region is arranged with exact position and at least partially over another color region. Security element according to at least one of claims 7 to 10, characterized in that at least one color region has a layer thickness which differs from the layer thickness of the other color regions. Security element according to at least one of claims 7 to 11, characterized in that the color regions are arranged relative to one another with a positional accuracy of less than 0.2 mm, preferably of less than 0.1 mm on the substrate. Data carrier, in particular security paper or value document with a security element according to one of claims 1 to 12. Apparatus for carrying out the method according to one of claims 1 to 6, with a first screen-printing cylinder having at least two screen areas separated by a separation area for applying two visually distinguishable color areas on a substrate, a second screen-printing cylinder having at least one screen area for applying at least one third color area to the substrate, - an impression cylinder, and - Means for positioning the first and second screen printing cylinder relative to each other with a position accuracy of less than 0.3 mm. Apparatus according to claim 14, characterized in that the separating region of the first screen-printing cylinder has a separating ring arranged in the interior of the screen-printing cylinder, in particular elastic separating ring. Apparatus according to claim 14 or 15, characterized in that the separating ring has a width of less than 20 mm, preferably less than 15 mm. Device according to at least one of claims 14 to 16, characterized in that the first and / or second screen-printing cylinder has a screen with at least two different mesh sizes. Device according to at least one of claims 14 to 17, characterized in that at least one drying device is provided for at least partially drying at least one color region.

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