DE102015005083A1 - Method for producing a security element with a register between printing element and watermark - Google Patents

Abstract

The invention relates to a printing method for producing a security element (1), wherein a substrate (2) has a watermark (5) which modulates the opacity of the substrate (2). On a front side (3), a printing element (9) is applied, which at least partially covers the watermark (5) and which contains at least a first and a second color layer (9, 22), the first color layer (9) being determined by means of the first Radiation (10) is ablatierbar and the second (22) not. The substrate (2) is irradiated from the backside (4) with the particular radiation (10) and the first color layer (9) is ablated from the particular radiation (10), the watermark (5) being used as an intensity mask to form the printing element in the register to modify the watermark (5). The first color layer (9) is a remitter colorant and the second color layer (22) is a luminescent colorant, the first color layer (9) covering the second (22). By ablating the first color layer (9) using the watermark (5) as a mask from the specific radiation (10), the second color layer (22) is exposed at some points (46) so that its luminescence effect at these points (FIG. 46) is stronger.

Description

The invention relates to a method for producing a security element, wherein a substrate is provided, which has a front and a back, at least for certain radiation is translucent and has a watermark, which modulates the opacity of the substrate is applied to the front of a printing element which at least partially covers the watermark and which contains at least a first and a second colorant, wherein the first colorant is ablatable by the first specific radiation and the second is not and the substrate irradiates from the backside with the particular radiation and the first colorant of the first predetermined radiation is ablated, the watermark being used as a mask to modify the printing element in the register to the watermark.

Such a method is from the DE 10 2012 003 601 A1 known.

To increase the security against forgery of protected objects, for example banknotes, watermarks are known. They are usually introduced in the production of the substrate from which the security element is made, usually a paper. Watermarks are easily recognizable when the security element is viewed through transmitted light, since they modify the opacity of the substrate. As a rule, in the production of the paper, the thickness of the substrate is varied, so that a reduction in thickness leads to an opacity reduction. However, other approaches to generating a watermark are also known, for example using so-called watermark colors, which also locally modify the opacity of the substrate.

Since watermarks are usually formed in the substrate in the production of the starting material for the security element, for example in the production of a banknote paper, it is fundamentally difficult in later printing to arrange printed elements in an exact position relative to the watermark, that is to pass. This problem arises regardless of the specific design of the printing element, not only when printing with different inks, but also during coating or application with printing elements, when applying transfer films or laminating or when applying a window suture.

The aforementioned DE 10 2012 003 601 A1 Therefore proposes to use the locally varying opacity of the watermark as a mask to modify a previously applied surface pressure element in the register to the watermark by means of laser radiation. As an example of the modification, ablation is mentioned. It is also apparent from the document that the pressure element may contain a mixture of substances that are modifiable and that are not modifiable. It is also known to make the printing ink visually visible or invisible. The watermark serves as a mask which modulates the intensity of the transmitted radiation, whereby the printing element is modified, for example ablated. As a result of the system, a perfect registration between the laser structuring, which is introduced into the printing element, and the watermark is achieved.

Based on this prior art, the invention is based on the object to provide a manufacturing method for a security element whose security against counterfeiting is increased again.

This object is achieved according to the invention with a method for producing a security element, wherein a substrate is provided which has a front and a back, at least for certain radiation is translucent and has a watermark, which modulates the opacity of the substrate, on the front Printing element is applied, which at least partially covers the watermark and which contains at least a first and a second colorant, wherein the first colorant is ablatable by the first particular radiation and the second is not, and the substrate is irradiated from the backside with the particular radiation and the first colorant is ablated from the particular radiation, the watermark being used as a mask to attenuate the intensity of the particular radiation; to modify the printing element in the register to the watermark, wherein the first colorant is a colorant remitting colorant and is disposed in a first color layer, and the second colorant is a luminescent colorant and is arranged in a second color layer, the first color layer the second and wherein the second colorant is exposed in places by ablating the first colorant using the watermark as a mask from the first specific radiation or changed in terms of the color effect.

The object is also achieved according to the invention with a method for producing a security element, wherein a substrate is provided which has a front and a back, at least for certain radiation is translucent and has a watermark, which modulates the opacity of the substrate, on the front a printing element is applied which at least partially covers the watermark and which contains at least a first and a second colorant, wherein the first colorant is ablatierbar by means of the first specific radiation and the second not, and the substrate from the back irradiated with the particular radiation, and the first colorant is ablated from the particular radiation, wherein the watermark is used as a mask to attenuate the intensity of the particular radiation to modify the print element in the register to the watermark, the first colorant being a remittant colorant having a color rbeffekt and the second colorant is a luminescent colorant, the first colorant and the second colorant are arranged in a common color layer and the second colorant is exposed in places by the first colorant using the watermark as a mask from the first specific radiation in terms Color effect is changed.

The second colorant is exposed in both variants mentioned (colorant in separate color layers or in a common color layer) by changing the color effect of the first colorant and thus repealed. This can be done by completely or partially removing the first colorant from the corresponding color layer. Alternatively, it is also possible that only the optical properties of the colorant are changed so that it no longer shows the color effect. This is possible, for example, by breaking bonds in the colorant, for example in pigments. It is therefore possible according to the invention to change the colorant with regard to the color effect, both by removing it from the layer (ablation) and, while it remains in the layer, but is modified there. As far as the option of ablation is described below, this is to be understood as an example only, and the corresponding description also refers to the variant that the first colorant is modified.

The luminescent image in the register for the see-through or supervisory image, the invention achieved either by providing the first colorant in a first color layer and the second colorant in a second color layer and the two color layers are arranged so that the first color layer on the second color layer, or that both colorants are in a common color layer. In the separate color layers, the first colorant is removed / modified by ablating / modifying the first color layer, and the second colorant in the second color layer is exposed. As a result, the brilliance of the second colorant is particularly large. If the colorants in a common color layer, the production is easier. The first colorant is then ablated / modified from the color layer so that the effect of the second colorant thus increases in the color layer.

The invention thus forms that in the DE 10 2012 003 601 A1 The concept disclosed by radiation to modify a previously applied flat printing element using the watermark as a mask to attenuate the intensity of the radiation, further implies that the particular radiation ablates only one of two colorants. Thus, at the locations where the first colorant is removed, the second luminescent colorant is exposed, which also means that the concentration of the second colorant in the layer system increases. When viewed normally, the security element provides a sight as seen from the DE 10 2012 003 601 A1 is known. When viewed under illumination that excites the luminescence of the second colorant, a luminescent image is displayed which is negative to the supervisory image under normal illumination and to the see-through image. The images are in perfect register with each other, since the second colorant is exposed there and gives off strongly the luminescent radiation, where the first colorant was removed.

Due to the design of the watermark, a multi-level or even continuous variation of the opacity of the watermark and thus a corresponding multi-level or uniform variation of the ablation / modification of the first colorant is possible. Also in these cases, the exposure of the second colorant and thus the intensity of the image recognizable in luminescence is inverse to the color impression, which is mediated in a plan view or in a view through the first colorant.

In a further education it sees the DE 10 2012 003 601 A1 in that the pressure element cooperates with an additional layer, the visual effect of which depends on the prior modification of the pressure element. Thus, it is known, for example, for optically variable layers that they are particularly clearly recognizable on a dark or black background in incident light. After the printing element has been provided with a contrast structure by the specific radiation, it is possible to apply an optically variable layer, ie without registration requirements, whose visual effect, due to the precise registration of the printing element acting as background, then automatically lies in the register with the watermark, although the optically variable one Layer itself was applied without Passeranforderungen. In this multilayer system, a part of the layer system is applied and illuminated with the specific irradiation. Another part of the layer system is then applied only after the exposure.

The physical removal of the first colorant can be done directly or indirectly. In the latter case, the particular radiation removes an element which in turn removes all or part of the first color layer or colorant. For example, a layer which influences the adhesion of the first color layer to the second color layer can be modified by means of the specific radiation. After the modification of this adhesion-influencing layer, in a further step the first color layer is then removed in those areas where the adhesion was modified (or not modified in the inverse case). The procedure is similar to the principle of the so-called wash color.

Another possibility is an indirect modification of a developer layer which, in cooperation with a developer or fixing medium, modifies the first color layer at those points at which the developer layer has been suitably exposed. Indirect influence is also possible in a two-stage process if the printing element has an adhesive layer for the first color layer, which is applied to the front side and exposed from the rear side with the participation of the watermark as a mask. In a second step, the first ink layer of the printing element can then be applied, which adheres only to those places where the exposure took place. Optionally, the exposed adhesive layer can also be acted upon here in an intermediate step so that it remains only in those areas in which a suitable exposure took place (positive effect) or remains in those areas in which no suitable exposure took place (negative effect).

In the context of this description, the term "pressure element" is understood to mean an element applied to a substrate, which optionally, after further processing, realizes a visually or mechanically evaluable element. Of course, most widely used are printing elements based on printing inks. As far as this description speaks of a printing ink, this is to be understood by way of example for a printing element.

As far as is spoken in this specification and in particular in the claims thus of "printing element" or "printing ink" and the application of this printing element is mentioned on the front over the watermark, it is also included that applied by a printing element layer system, only a part of the layer system and is exposed to the specific radiation; the other part is then applied after these steps and interacts with the exposed portion of the layer system to create a printed image in the watermark to the watermark.

Colorants or coloring substances are known to be subdivided into dyes and color pigments. Dyes are colorants that are soluble in the application medium, whereas color pigments are colorants that are insoluble in the application medium.

The terms "colorant" and "color" are not limited to a colorful sensory impression with respect to the remittant colorant. An achromatic effect, for example by black or metallic colorants, is possible for the remittant colorant. The remittant colorant may in particular achromatic pigments, such as. As black or silver pigments, colored pigments, effect color pigments or color-shift pigments.

The watermark can be generated by varying the thickness of the substrate at a constant density, by varying the density of the substrate with a constant thickness or by a so-called watermark color. The latter are also referred to as "spurious" watermarks. The watermark can binarise the opacity of a substrate, i. H. it produces a structure which can be seen in the transparency in that at individual points the substrate is less opaque or more translucent than at other points. But there are also watermarks in the sense of a gray scale modulation possible, which modulate the opacity or translucency between two maximum values. In the transmitted light view, one then recognizes a grayscale image. Both types of watermarks are equally suitable for the present printing process. In the case of a watermark which is designed in the manner of a gray-scale image, it is, of course, particularly advantageous to use an ink whose modifiability goes beyond a simple threshold modification, the modification of which thus knows more than two states. The multi-level modulation by the watermark is then converted into a corresponding multi-stage modification of the printing element.

The first color layer or colorant and the particular radiation are matched to one another such that the particular radiation is capable of ablating / modifying the first colorant, the watermark modulating the opacity of the substrate being used as a mask to modulate the colorant Intensity of the particular radiation is used. The term "certain radiation" expresses this. The ablation / modification is achieved when the particular radiation at the front has a suitable intensity. The watermarked opacity modulation modulates the intensity of the radiation on the front face on which the printing element is located. The radiation intensity on the back is therefore so adjusted that the opacity modulation caused by the watermark on the front side results in a radiation modulation which modulates the modification / ablation effect. In other words, the radiation intensity on the back side is chosen so that where the watermark causes the lowest opacity in the substrate, the greatest effect occurs where the watermark causes the highest opacity of the substrate no or only a very small ablation / modification is achieved. Thus, the watermark serves as an intensity mask when the substrate is irradiated with the particular radiation.

The exposed second luminescent colorant shows in the luminescent image, which is recognizable, for example, when viewed under UV-containing illumination, a main pattern, which is defined by the structure of the exposed second colorant. If the particular radiation is applied so that the first colorant is either completely or completely removed, the luminescence image corresponds to a pure black and white image without tints. Equally, it is also possible to adjust the ablation by the watermark so that a partial ablation of the first colorant takes place. This partial ablation weakens the absorbing action of the first colorant such that at the partially ablated sites in the luminescent image there is an intensity intermediate between that obtained upon complete exposure of the second colorant and that present with unaffected first colorant. Alternatively and additionally, of course, a grayscale representation by half or multi-tone screening is possible, as is known in the gray scale representation by screened image representation. Finally, the watermark is then patterned accordingly to provide the appropriate variation of opacity as an intensity mask for the effect of the particular radiation on the first colorant.

Since ablation usually requires a comparatively high radiation intensity, it is advantageous to use a beam that is scanned over the back of the substrate. The beam may be in the form of a laser beam, for example. It is then not only easy to provide the required radiation intensity, also the intensity adjustment can be done easily, since it is less effort to adjust a beam in its intensity, as to effect a homogeneous intensity adjustment of a fanned light beam. Nevertheless, for certain embodiments, a far field irradiation of the particular radiation is possible.

The use of a rasterized beam has the advantage that the intensity of the particular radiation can be varied in addition to using the watermark as a mask to effect additional patterning according to a first auxiliary pattern. Of course, this additional pattern is not in the register for the watermark. It is therefore provided in a development that the specific radiation is structured or modulated so that a first additional pattern is omitted, that is not irradiated, in which then consequently the first colorant is not ablated. As a result, in this first additional pattern, the intensity of the luminescence radiation from the second colorant remains further attenuated due to the non-ablated first colorant, which makes the first additional pattern clearly recognizable in the luminescence image.

In a development, a second additional pattern is formed with the second colorant. This development can be combined with the training that forms the first pattern. The second additional pattern is produced by also removing the second colorant in the exposed areas with another radiation. In the luminescence image, the second additional pattern can then be recognized by locations of no luminescence. In the region of the second additional pattern not only the first colorant is removed, but also the second luminescent colorant. This embodiment can be realized particularly simply by the fact that the specific radiation and the further radiation originate from the same laser source, for example by the laser source emitting pulsed laser radiation to provide the specific radiation, ie ablating the first colorant and continuous wave radiation to the second colorant ablate.

In another development, which can be combined with those of the first and / or second additional pattern, a third additional pattern in the form of a recess in the color layer is provided when applying the first and second color layer. The effect of this third additional pattern is substantially the same as that of the second additional pattern, however, this third additional pattern can be placed completely independent of the variation of opacity by the watermark, since no color layer removal is necessary in the structure of the third motif. It is also possible in areas outside the watermark.

As a second color coat, in particular metallic pigments come into question. They achieve an additional protection against counterfeiting, since in addition a gloss effect is perceptible, which at those points, at which the first color layer was ablated completely or partially, fails or is reduced accordingly.

The first color layer and the second color layer are selected such that in a wavelength range in which the particular radiation is located, the first color layer absorbs more strongly than the second color layer. Preferably, infrared radiation is used as the specific radiation, and the second color layer is transparent in this area. A particularly preferred spectral range of the infrared radiation is the spectral range between 1000 nm and 1100 nm.

The term ink used here stands out for the printing effect achieved by the watermark-masked and radiation-based modification. Of course, the ink itself can also include structures that go beyond conventional printing systems, such as a foil coating or metallization.

Items to be protected within the scope of this description may include, for example, security papers, identity and value documents (such as banknotes, passports, passports, shares, bonds, certificates, vouchers, checks, tickets, etc.) as well as product security elements such as security items. As labels, seals, packaging, where a watermark is possible.

The term security paper is understood here to mean, in particular, the precursor that can not yet be processed to a document of value (eg a banknote) which, in addition to the printing produced according to the invention, can also have other authenticity features (such as luminescent substances provided in the volume, for example). Under value documents here on the one hand from security papers produced documents, eg. B. banknotes understood. On the other hand, value documents can also be other documents and articles that are processed with the printing method according to the invention, so that the value documents have non-copyable authenticity features, whereby an authenticity check is possible and at the same time unwanted copies are prevented.

The substrate is particularly preferably made of paper made of cotton fibers, as used for example for banknotes. Preferably, the substrate can also be made of paper of other natural fibers, also preferably of synthetic fibers, d. H. a mixture of natural and synthetic fibers. Further preferably, the substrate consists of a combination of at least two superimposed and interconnected different substrates, a so-called hybrid. It may be, for example, a combination of plastic film paper or even a three-layer composite, such as plastic film-paper-plastic film, d. H. a substrate of paper is covered on either side by a plastic film, or paper plastic film paper, d. H. a substrate made of a plastic film is covered on each of its two sides by a paper substrate.

Optionally, the substrate consists of an at least partially transparent plastic film. The watermark is generated in this case by a color which is applied to one side of the substrate and whose hue is at least similar to the hue of the substrate. Such a watermark is for example off DE 10 2009 056 462 A1 known.

Under translucency or translucent in this description, the partial translucency of a body understood, so the property of transmitting light scattering. Translucency is u. a. in contrast to the transparency (= image or view permeability) to see. The reciprocal property of translucency is opacity. As far as there is talk here that a watermark modulates the opacity, it can equally be said that it inversely modulates the translucency.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the specified combinations but also in other combinations or alone, without departing from the scope of the present invention.

The invention will be explained in more detail by way of example with reference to the accompanying drawings, which also disclose features essential to the invention. Show it:

1a and 1b a schematic representation of a substrate in a sectional view ( 1a ) or in plan view ( 1b ) to illustrate the opacity modulation by the watermark,

2a and 2 B Schematic representations of the substrate of the 1 for generating a watermarked printed image,

3a and 3b a schema representation similar to the 1a and 1b relating to an embodiment in which the watermark is generated by a watermark color,

4 a representation similar to the 2 for the substrate of 3a and 3b .

5a a schema representation similar to the 2 for an embodiment in which a non-modifiable coating is provided on the front side of the substrate,

5b and 5c Views of the substrate of the 5a from the back or the front after a modification,

6 Views of nine pictures showing the security element of the 1 to 2 during manufacture and in different viewing conditions, and

7 to 9 Representations similar to the 6 for various modifications and developments of the security element.

1a shows in a sectional view a security element 1 , wherein for simplicity only one substrate 2 is drawn. The substrate 2 has a front 3 on (which is arranged in the figures below without further restriction) and a rear side 4 , In the substrate 2 is a watermark 5 incorporated the thickness of the substrate 2 and thus modulates its opacity. This opacity modulation is in 1b shown, which is a view from the front 3 of the substrate 2 schematically shows. There are areas 6 with high opacity in places where the substrate 2 has the maximum (not diminished) thickness. In areas 7 in which the thickness is reduced by an average amount, the substrate has 2 a medium opacity. In one area 8th in which the thickness is greatly reduced, the substrate has 2 a low opacity or a high translucency.

To create a printed image that has been adapted to the watermark, it is printed on the front side 3 an ink layer 9 applied, whose remittierendes colorant is ablatierbar by means of laser radiation or modifiable in terms of a color effect. Under the ink layer 9 there is a fluorescent color layer 22 containing a luminescent colorant. 2a and 2 B show the substrate 2 with on the front 3 applied ink layer 9 and fluorescent dye layer 22 , They are (still) not further structured in this state, but at least partially cover the area where the watermark is 5 in the substrate 2 is available. Here are in 2 B the ink layer and the fluorescent ink layer in a common color layer 64 which contains both the remitting and the luminescent colorant.

From the front 3 now becomes a laser beam 10 guided over the substrate. He radiates through the substrate 2 , The wavelength of the laser beam is such that the remitting colorant is absorbed by the radiation and modified or ablated. The laser beam 10 will depend on the opacity of the substrate 2 which by the watermark 5 modulated, attenuated. At a position 10a where the substrate has high opacity by the watermark becomes the laser beam 10 strongly weakened. At a position 10b where the substrate has the least opacity, the laser beam is least attenuated. In 2a and b is this schematically by the thickness of the laser beam 10 illustrated. In fact, of course, only the intensity of the laser beam 10 but not its radiation cross section when passing through the substrate 2 weakened.

The intensity of the laser beam 10 is set so that the watermark intensity mask as a modulation of the effect on the remittant colorant z. B. the ink layer 9 causes the laser beam 10 on the front 3 applied ink layer 9 or color layer 64 has: in the area 8th with low opacity, the remittant colorant is at most ablated or modified, in areas 7 with medium opacity to a lesser degree, and in areas 6 with maximum opacity, the least or possibly even no ablation / modification occurs. Of course, this only applies insofar as the ink layer 9 / the color layer 64 on the front side 3 the area covered in the watermark 5 in the substrate 2 is trained. The fluorescent colorant is from the laser beam 10 not ablated / modified, z. B. for the laser beam 10 transparent.

The described embodiment can be modified such that instead of a watermark which modulates the opacity by a thickness variation of the substrate, a so-called "false" or printed watermark occurs, that is to say a watermark which is deposited on the substrate 2 was generated by a so-called watermark color.

The 3a and 3b schematically show the provision of such a printed watermark. On the back 4 of the substrate 2 becomes a watermark color 11 printed. The watermark color 11 penetrates accordingly 3b in the substrate 2 and causes after drying or other suitable processing, a translucency increase 12 in the substrate 2 in the places where the watermark color 11 was printed.

Press now, as in 4 , which by way of example only have two layers of paint 9 and 22 shows, but also with a common color layer 64 can be realized, shown, the substrate 2 with the printed watermark 12 with the laser beam 10 , in turn, gives the effect that the laser beam 10 at positions 10a in which the watermark or the watermark color the translucency of the substrate 2 increased, less attenuated in intensity than at positions 10b where the watermark does not have this effect. Again, ablation / modification of the remitter colorant in the exact register to the watermark is obtained without the application of the ink layer 9 , Paint layer 64 this passer had been set.

The 5a to 5c relate to a third embodiment, in addition to the front 3 one not by the laser radiation 10 Modifiable coating 13 was applied to the laser radiation 10 is transparent and thus does not weaken it. Again, a purely exemplary system with two layers 3 and 22 shown. A common color layer 64 is equally possible.

5a shows a sectional view similar to the 2 , wherein now in some areas, the not modifiable by the laser radiation, but still absorbing coating 13 is applied. 5b shows a plan view of the back 4 with the coating 13 ,

5c shows a plan view of the front 3 after irradiation with the laser radiation 10 , Due to the different opacity of the substrate in the area of the watermark 2 becomes the ink layer 9 different degrees of laser radiation 10 influenced, so that the different areas 14 . 15 and 16 result. In the area 16 is the ink layer 9 almost unaffected, because the energy of the laser beam due to the opacity of the substrate 2 is greatly attenuated. In the area 14 is the ink layer 9 due to average laser energy dissipation through the substrate due to the average opacity of the substrate 2 modified in a moderate Maßse, for example, ablated. The laser beam had a strong effect on the ink layer 9 in the area 15 because there is the substrate 2 has a low opacity and weakened the laser beam only slightly.

The variant of 5 can also be designed so that the coating 13 not the laser radiation absorbed, but a luminescent ink layer is on the back of the substrate in transmitted light additive color mixing with the luminescent colorant, which was exposed differently on the front as described by means of the laser radiation.

Of course, the described embodiments can also be realized with a watermark that was generated by a watermark color and not by a thickness modulation.

Of course, it is basically possible for all embodiments to use a combination of watermark color and thickness modulation. A watermark ink is available, for example, from Sun Chemical under the designation 669440 Vernes UVSP (art.No .: JV 40000009).

Of course, the approaches described here can also be carried out on both sides of a substrate, wherein the color layers are then applied alternately on front and back of the substrate, so that they do not overlap.

In addition, two different ink layers can be used, which can be modified by radiation of different spectral ranges. This makes it possible to work with different intensity profiles for these two radiations or to print on the front and back the same area with radiation-modified ink layers in the register to the watermark. For this purpose, a first ink layer is applied to the front and a second ink layer on the back. Subsequently, these ink layers are exposed and modified by laser radiation from the back side (for the ink layer located on the front side) or the back side (for the ink layer located on the front side).

For the ink layers, three examples are described below:

Example 1:

A black, call-based offset color was printed over the area of a watermark after a fluorescent ink layer had been printed. The paint was dried for several days and then ablated by an ND vanadate laser from the back of the color on the front. In areas of low paper thickness, i. H. maximum translucent watermark was 80% to 95% of the color removed. In areas of maximum paper thickness, i. H. minimal translucency of the watermark, only 10% to 30% of the color was ablated.

Example 2:

The area of a watermark on the front side was overprinted by means of an OVI screen printing ink WP from the manufacturer SICPA. The paint dried out for several days. Subsequently, the color on the front side was ablated by means of a Nd: Yag laser from the rear side. In areas of low paper thickness, 80% to 95% of the paint was removed. In areas of maximum paper thickness, 10% to 30% of the paint was ablated.

Example 3:

Using a magnetic OVMI screen-printing ink from manufacturer SICPA, the area of a watermark on the front side was overprinted after a fluorescent ink layer had been printed. The paint dried out for several days. Subsequently, the color on the front side was ablated by means of a Nd: Yag laser from the rear side. In areas of low paper thickness, 80% to 95% of the color except a yellow colorant was removed. In areas of maximum paper thickness, 10% to 30% of the paint was ablated.

The 6 to 9 show different images of the security element during different stages of manufacturing. For the 6 to 9 the following applies in principle:
The upper lines of the Fig. Shows the view of the security element before applying the color layers 9 and 22 , The middle lines show the views after application of the color layers 9 and 22 but before the modification by the radiation. Finally, the bottom lines show the completed security element. The left columns show the views that result from normal top view of the security element. The middle columns show the respective see-through image and the right columns show the luminescence image after excitation with UV radiation.

The in the 6 to 9 Hatches used are assigned to the individual views / functions. A vertical bar is used for the brightness of the background of the respective images, with increasing baring indicating a decreasing brightness. A vertical hatch denotes the brightness of elements in the see-through image. Crosshatching denotes the brightness of elements in the supervisory image. A vertical hatch denotes the brightness of structures in the luminescence image. The hatching or hatching distance symbolizes the brightness. A wider-meshed hatching or stroke therefore illustrates a lighter structural element, a closer meshing or brightness a darker element.

Stronger hatched sections are therefore darker in the respective view than less densely hatched sections.

Outlines of corresponding elements are entered in all pictures. This was done solely for better recognizability of the images. In fact, there are no separate outline boundaries in the images.

Dashed lines illustrate an area over which the particular radiation is applied. They are not visible in the views, but entered only to illustrate the application of the laser radiation.

To simplify the illustration, only one black-and-white representation is used in the exemplary embodiments

6 shows a first embodiment of the manufacturing method of a security element with Passer between printing element and watermark. image 23 shows the security element before applying the pressure element in supervision. Unsurprisingly, there is a white area 32 to see. image 24 shows the same manufacturing status in review. In front of a gray area 33 the watermark stands out, coming from a recumbent bright rectangle 37 and a contrast darker rectangle 36 is formed. Both rectangles 37 are brighter than the gray area 33 , image 25 Finally, the fluorescence image shows a black area due to fluorescence colorants not yet present in this production state 34 is. It is assumed here that the substrate of the security element does not fluoresce.

images 26 to 28 show again in plan view (picture 26 ), Review (pic 27 ) and fluorescence view (Fig 28 ) the state of the security element after applying a printed image 38 , The printing element comprises a metallic silver pigment which is a remitter colorant. Furthermore, the printing element has a fluorescent ink layer 22 which has a luminescent colorant and is built up under an overlying ink layer containing the remittant colorant. The colorants may alternatively (not shown) also lie in a common color layer.

In the picture 26 the print image rises 38 black in front of the white area 32 from. Additionally, in the picture 26 another irradiated area 60 marked by a dashed line. This is the area where laser radiation will subsequently be applied. In the picture 27 As seen at this stage of production, the watermark consisting of the standing rectangle 36 and the lying rectangle 37 , in front of the gray area 33 , covered by a black ellipse 49 passing through the print image 38 is formed. In the fluorescence view the picture shows 28 against a black background through the black area 34 , a darkened fluorescence image 39 , which results from the fact that the underlying fluorescence color layer 22 from the overlying ink layer 9 is covered and only to a very limited extent fluorescence radiation penetrates to the surface.

images 29 to 31 show top view, see-through and fluorescence images after applying the laser radiation in the irradiated area 60 , wherein the watermark is used as an intensity mask, as based on the 1 to 5 previously explained.

For the ablation / modification of the printed image 38 The watermark, consisting of the rectangles, acts 36 and 37 , as an intensity mask. This arrives in the area of the lying rectangle 37 a maximum radiation intensity on the printed image 38 and in the background area a minimum intensity. In the area of the standing rectangle 36 becomes the print image 38 with a mean intensity, which lies between the two extreme values applied. This causes the printed image 48 is structured in three areas, the perfect passport to the watermark 5 lie. An unchanged section 42 lies in those areas of the printed image 38 that do not cover the watermark, so are illuminated by the radiation with the minimum intensity. A gray section 40 lies in the areas of the printed image 38 which the standing rectangle 36 cover. A bright section 41 is finally through those areas of the print image 38 formed the rectangle lying 37 cover. This breakdown and patterning of the printed image 38 is in the picture 27 , which shows the supervision of the finished structured security element, clearly recognizable.

In the transparent picture 30 affects the structured pressure element 38 in superposition with the intensity modulation by the watermark, namely the rectangles 36 and 37 , out. The unchanged section 42 of the supervisory picture leads to a black area 45 in the transparency, because there the translucency of the security element through the unchanged layer structure of the printed image 38 continues to be completely reduced. In a bright area 44 , the bright section 41 corresponds, adjusts a brightness of the transparent image, which is opposite to the lying rectangle 37 is reduced. This reduction is due to the small remaining residual thickness of the visible absorption layer structure of the printed image 38 caused. A dark area 43 is according to the gray section 40 educated. Here is the translucency with respect to the standing rectangle 36 reduced, but not as strong as in the black area 45 ,

In the ablation of the printed image 38 is, as already described above, only the remittant colorant, but not the luminescent colorant removed, removed, reduced or modified. This results in the fluorescence image 31 a darkened region 48 whose fluorescence intensity is the darkened fluorescence image 39 equivalent. According to the effect on the remittant colorant to get further a bright region 46 and a dark region 47 in location and location the gray section 40 / dark area 43 or bright section 41 / bright area 44 correspond.

7 shows a development of the manufacturing process in a view similar to the 6 , Identical elements are provided with the same reference numerals. The main difference to the embodiment of 6 is that the irradiated area 60 a recess 61 in which the particular radiation is not applied. This is dashed in the picture 26 indicated. The recess 61 leads to the fact that in the supervision picture 29 another unchanged section 50 according to the outlines of the recess 61 is formed. Also in the transparent picture 30 you get in this way another black area 51 with the same dimensions. In the fluorescence image 31 there is another darkened region 52 also with the same dimensions and outlines. In this way it is possible to provide a first additional pattern in the security element.

8th shows a further modification, wherein now in the irradiated area 60 a diamond-shaped spot in the example 62 is irradiated with additional radiation, which is designed so that it also the fluorescent color 22 away. The result is obtained in the supervisory picture 29 a diamond-shaped surface 53 in which no printed image 38 more is available. In the illustration of FIG. 29 This is illustrated by the diamond-shaped surface 53 with the dashed line of the background crying surface 32 , usually a banknote paper, is provided. The rhombic surface 53 However, due to the original printing, the degree of gloss may be different from the background, so that the diamond-shaped surface 53 shows a different gloss when viewed obliquely than the background of the white area 32 ,

In the transparent picture 30 The diamond-shaped surface is divided into two triangular parts 54 . 55 split, because the stain 62 the two rectangles 36 . 37 , which have different transmissions, covered. The two triangular parts 54 and 55 each have in the see through the brightness of the underlying standing rectangle 36 respectively. 37 , This is due to the location of the stain 62 certainly. At another location of the spot 62 results in a different or no division in the transparency.

Finally, the fluorescence image also shows a diamond-shaped surface 56 where the fluorescent color layer 22 In this diamond-shaped area, the fluorescence intensity of the background, ie a black area, is present.

9 shows a further embodiment, which as a result of the 8th comes very close. Here is not a spot 62 irradiated with additional laser radiation, but it is when applying the printed image 38 a pressure relief 63 intended. It results in terms of the transparency 30 and the fluorescence image 31 same conditions. Also the supervisory picture 29 shows a representation which, when viewed vertically, substantially the image of the supervisory 8th equivalent. However, because in the diamond-shaped area 56 from the beginning no printed image 38 was present, is also the gloss level, ie the impression at an oblique view in the diamond-shaped surface 59 no different than in the background, ie in the white area 32 ,

Of course, the developments according to the 7 to 9 can be combined arbitrarily. So it's possible the recess 61 of the irradiated area 60 with the additional irradiation of the spot 62 to combine. Also a combination with the pressure relief 63 is possible. Similarly, using a separately irradiated spot 62 with the pressure relief 63 be combined. Of course, all three measures, so the use of a recess 61 in the irradiated area 60 , a separately irradiated spot 62 and a pressure relief 63 , be combined.

The embodiments shown above see a two-level watermark with the rectangles 36 . 37 in front. This was chosen because of the clarity of the description. Of course, a single-level watermark and a multi-level or even an opacity continuously varying watermark may be used. The described principles apply equally.

In the described embodiments, simple geometric figures for the structures used were shown. Of course, this is purely exemplary. It is also possible to use complex geometric figures or image representations. Of course, this also applies to the developments according to 7 to 9 , Here motifs or alphanumeric representations, in particular banknote values, currency information or information about the publisher of a banknote or a security element can be coded accordingly.

In particular, the invention can also be realized by the following embodiment:
The print motif is applied with at least one printing ink which has at least the following substances: Laser markable (IRA), preferably metallic pigments and UV-transparent, visibly luminescent, IR transparent pigments (preferably in the range 1000 nm to 1100 nm). IR transparent pigments and / or colorants may also be included, among others. In this case, the luminescence of excitable under UV radiation pigments by the z. B. weakened metallic pigments.

The print motif is at least partially printed over the watermark, preferably on the substrate screen side (rougher than the felt side). The print motif can consist of a closed surface and / or additional ornaments and / or be screened.

There is a laser marking from the opposite side of the substrate - through the substrate, whereby the laser beam is attenuated accordingly due to the modulated paper thickness or opacity in the lighter areas of the watermark.

The laser should be adjusted so that the full thickness of the paper (outside the watermark area) will not cause any marking or ablation. At the same time, it must be ensured that the contrast in the sub-region modulated by the laser through the opposite substrate side over the watermark is to be kept as high as possible.

The area to be marked with the laser must be selected so that the tolerances between printing and laser marking are maintained. The size of the surface results from the desired machine speed, but may not be less than 1.5 cm ² in the rule.

Decisive for the effect is the laser operating mode. In order to achieve a modulated ablation of IRA, preferably metallic pigments, pulse operation should be selected.

In continuous wave operation, the entire pigment is destroyed in the present case, whereas in pulsed operation only the optical properties of a metallic pigment are changed due to non-linear effects, for example, bonds are broken, so that the color effect emanating from the unmodified metallic pigment is changed or fails. The following laser parameters are possible: 10 W maximum power in continuous wave mode, 30 kHz to 50 kHz pulse frequency, 5 ns to 50 ns, preferably 8 ns to 15 ns pulse length, 0.2 mm to 0.8 mm spot diameter (depending on the area to be exposed or Machine speed), 100 W maximum total energy (typically 50 W for silver pigments).

Due to the modulated ablation IRA, preferably metallic pigments are pulsed at the same time the pigments "luminescent" under UV radiation are "exposed". This produces a modulated luminescent motif perceptible under UV light. As a result, the part of the watermark marked by the laser is visible under UV radiation as a modulated motif, the non-marked areas also luminescing weakly and complementing the motif. At the same time, this motif is also recognizable under visual light as a modulated motif, which preferably has a metallic effect. This motif is perfectly matched with the watermark in the review.

For the further education of 7 can apply:
In the area to be marked in pulse mode (main motif), a preferably alphanumeric motif is left out negatively (motif 1, not marked). As a result, in this region (motif 1), the luminescence power of the pigments excitable under UV radiation continues to be weakened by the non-ablated metallic pigments, and thus the motif 1 can be recognized under UV light. At the same time, this motif 1 is also recognizable under visual light as an alphanumeric motif, which has the full metallic effect. This motif 1 is visible in the transparency due to its low opacity - appears darker than its surroundings.

For the further education of 8th can apply:
In the area to be marked in pulse mode (main motif), a preferably alphanumeric motif is marked in cw mode (motif 2, cw laser marking). As a result, not only the metallic pigments but also the pigments which are luminescent under UV radiation are ablated in this region (motif 2) - thus the motif 2 is recognizable under UV light as a black or dark motif (non-luminous) , Under visual light in the top view, the subject 2 remains invisible. In the tilted state, on the other hand, the motif 2 can be recognized as a latent motif (no color difference, only gloss difference). This motif 2 is not visible in the review, since the opacity of the color (lasered in pulse mode compared to the cw operation) has not changed.

In general, the particular radiation is to be chosen so that the substrate as little or no absorption of the radiation occurs, which would lead to a change in the substrate. Both continuous wave lasers and pulsed lasers are possible for this purpose. An example of a suitable CW laser is the model Innoslab, IS8I-E, manufactured by Edge-Wave GmbH, which is a Nd: YVO ₄ -based laser at a wavelength of 1064 nm. It provides a power of 100 watts in continuous wave mode. At a scan speed of 2.5 m / s to 5 m / s, the ablation of a soot-based color can be performed.

If an IR-modifiable color is used as the ink layer, there is the advantage that the printed image and the verification of the register can be machine-based by means of infrared measurement. The same applies to the use of a luminescent in the UV range colorant.

Transmitted light is for the purposes of this invention, when an illumination of the substrate from the side opposite to the viewer, d. H. the illumination through the substrate takes place. Incident light is in the sense of this invention, when a lighting of the substrate from the side of the viewer is made.

The watermark may be a multi-level modulated 3D, a two-level highlight, or a high resolution pixel watermark that modulates the opacity of the substrate by thickness variation. A combination of the different types of watermarks is also possible, especially if the main watermark motif is a portrait that can not be overprinted.

LIST OF REFERENCE NUMBERS

1

security element

2

substratum

3

front

4

back

5

watermark

6, 7, 8

Area

9

Ink layer

10

laser beam

10a, 10b

position

11

Watermark Color

12

Transluzenzerhöhung

13

coating

14, 15, 16

Area

17

window thread

18, 19

Area

20, 21

section

22

Fluorescent ink layer

23-31

image

32

white area

33

gray area

34

black area

35

watermark

36

standing rectangle

37

lying rectangle

38

print image

39

darkened fluorescence image

40

gray section

41

bright section

42, 50

unchanged section

43

dark area

44

bright area

45, 51

black area

46

bright region

47

dark region

48, 52

darkened region

49

black ellipse

53, 56, 59

diamond-shaped surface

54, 55, 57, 58

triangular part

60

irradiated area

61

recess

62

spot

63

pressure recess

64

coat of paint

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102012003601 A1 [0002, 0005, 0011, 0011, 0013]
• DE 102009056462 A1 [0033]

Claims (10)

Method for producing a security element ( 1 ), wherein - a substrate ( 2 ), which has a front and a back ( 3 . 4 ), at least for certain radiation ( 10 ) is translucent and a watermark ( 5 ), which reduces the opacity of the substrate ( 2 ), - on the front ( 3 ) a printing element ( 9 ), the watermark ( 5 ) at least partially and containing at least a first and a second colorant, wherein the first colorant by means of the first specific radiation ( 10 ) ablatierbar and the second is not, and - the substrate ( 2 ) from the back ( 4 ) with the particular radiation ( 10 ) and the first colorant of the particular radiation ( 10 ) is ablated, the watermark ( 5 ) is used as a mask to attenuate the intensity of the particular radiation to the pressure element ( 9 ) in the register to the watermark ( 5 ), characterized in that - the first colorant is a colorant remitting colorant and in a first colorant layer ( 9 ) and the second colorant is a luminescent colorant and in a second color layer ( 22 ), - the first color layer ( 9 ) the second ( 22 ) and - the second colorant in places ( 46 ) is exposed by using the first colorant using the watermark ( 5 ) as a mask of the first specific radiation ( 10 ) in terms of the color effect or from the first color layer ( 9 ) Will get removed. Method for producing a security element ( 1 ), wherein - a substrate ( 2 ), which has a front and a back ( 3 . 4 ), at least for certain radiation ( 10 ) is translucent and a watermark ( 5 ), which reduces the opacity of the substrate ( 2 ), - on the front ( 3 ) a printing element ( 9 ), the watermark ( 5 ) at least partially and containing at least a first and a second colorant, wherein the first colorant by means of the first specific radiation ( 10 ) ablatierbar and the second is not, and - the substrate ( 2 ) from the back ( 4 ) with the particular radiation ( 10 ) and the first colorant of the particular radiation ( 10 ) is ablated, the watermark ( 5 ) is used as a mask to attenuate the intensity of the particular radiation to the pressure element ( 9 ) in the register to the watermark ( 5 ), characterized in that - the first colorant is a colorant-effecting colorant and the second colorant is a luminescent colorant, - the first colorant and the second colorant are in a common colorant layer ( 64 ) and - the second colorant in places ( 46 ) is exposed by using the first colorant using the watermark ( 5 ) as a mask of the first specific radiation ( 10 ) is changed in terms of its color effect or removed from the ink layer. Method according to claim 1 or 2, characterized in that the first specific radiation ( 10 ) is structured or modulated in such a way that a first additional pattern ( 50 ) is left out, in which the first colorant is not changed or removed. Method according to one of claims 1 to 3, characterized in that the second colorant is ablatierbar by means of a further radiation or changeable in terms of its color effect and the second colorant at portions of the exposed locations by irradiation of the further radiation ( 22 ) ablated / changed according to a second additional pattern. Method according to claim 4, characterized in that the particular radiation ( 10 ) is pulsed laser radiation and the further radiation is cw laser radiation, preferably the same laser. Method according to one of the preceding claims, characterized in that the pressure element ( 9 ) is applied so that it is above the watermark ( 5 ) a recess ( 56 ) according to a third additional pattern. Method according to one of the above claims, characterized in that the remittierende colorant has metallic pigments, effect color pigments or color-shift pigments. Method according to one of the above claims, characterized in that the luminescent second colorant has pigments which are transparent in the IR spectral range, preferably in the spectral range from 1000 nm to 1100 nm. Method according to one of the preceding claims, characterized in that the first colorant is removed by ablating it. Method according to one of claims 1 to 9, characterized in that the pressure element comprises a coating, transfer film, laminating film and / or a window thread.

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