EP1776674B1 - Data carrier with security element and method for the production thereof - Google Patents

Description

The invention relates to a data carrier, in particular a document of value, such as a banknote, an identity card and the like, with a security element having a printed image and a laser marking at least partially overlapping the printed image. The invention further relates to a method for producing such a data carrier, a method for producing a data carrier with a security element with two printed images and a method for producing a plurality of individual benefits of data carriers on a sheet or a roll.

Data carriers in the context of the present invention are in particular security or value documents, such as banknotes, passports, identity documents, check forms, shares, certificates, stamps, vouchers, air tickets and the like, as well as labels, seals, packaging and other elements for product assurance. The term "data carrier" in the following includes all such documents and product securing means.

Identity cards, such as credit cards or identity cards, have long been personalized by laser engraving. In personalization by laser engraving, the optical properties of the substrate material are irreversibly changed by suitable guidance of a laser beam in the form of a desired marking. Such a laser marking makes it possible to combine the individualization of the data carriers with security elements and to integrate them more freely into the printed image than in conventional individualizations, for example in the case of known indexing methods.

From the publication US-A-4,234,214 is a banknote with a readable code of letters and numbers known, which is used for clear identification the banknote comprises a serial number. The readable code is applied at a first position of the banknote in positive form and at a second position in negative form with a multicolored background. The negative form of the code can be generated by ablating a previously applied ink layer with a suitably controlled laser beam.

Since the same paper run as in a printing press is used in the laser marking of previously applied printing layers, register fluctuations of the same order of magnitude occur as between conventional printing methods. The register variations arise, for example, due to production tolerances in the production of masters, printing plates or printing screens, due to spacing variations of the printing area from the edges of the preprinted substrate in a machine change between different printing processes, such as screen printing, simultaneous printing, intaglio printing, ciphering, or because the substrate and the Change plates in the printing process, for example in a Auswalzschritt, or the associated operations, such as a drying step in their dimensions. The register variations can be up to +/- 3.5 mm in unfavorable cases. In general, security printing is expected to have subsurface and intaglio printing with fluctuations of +/- 1.5 mm, between background and screen printing with fluctuations of +/- 2 mm. Foil elements can be applied with fluctuations of +/- 1.5 mm relative to a background pressure.

Such register variations are especially noticeable in the case of round or rounded printing elements, which are marked along a concentric or rounding path.

Out WO 00/43216 A is a tamper-proof document with a security feature in the form of a perforation known. The image formed by the perforation pattern corresponds to another image created, in particular, by laser ablation. Both images, ie both the perforation pattern and the laser ablation, coincide exactly

Proceeding from this, the present invention seeks to provide a data carrier of the type mentioned and a manufacturing method with which the disadvantages of the prior art are overcome. In particular, register fluctuations between two printed images or between a printed image and a laser marking should be avoided or rendered largely invisible on visual inspection.

This object is achieved by the data carrier with the features of the main claim. A method for its production, a method for producing a data carrier with a security element with two printed images printed are given in the independent claims. Further developments of the invention are the subject of the dependent claims.

According to a first aspect of the invention, the security element of a generic data carrier on the print image at least partially overlapping laser modification area, which stands in the register to the laser marking and in the overlap region with the printed image, the visual appearance of the printed image is modified by the action of a laser beam, wherein the laser marking and the laser modification range does not coincide.

In this aspect, the invention is based on the idea of permitting register fluctuations between the printed image and the laser marking, and of modifying the visual appearance of the printed image in a subarray in the register for laser marking in such a way that registration fluctuations between the printed image and the laser marking are visible to the viewer Background and instead the (perfect) register between the laser marking and the modification area dominates the visual appearance of the security element.

According to the invention, the laser modification region forms an outline of a predetermined width which surrounds the edge of the printed image. The width of the circumferential contour is matched to the size of the register fluctuations between the printed image and the laser marking, so that all typically occurring register fluctuations can be compensated.

The print image of the security element can be embodied, for example, in screen printing, offset printing, indirect high-pressure, high-pressure, digital printing, color-guiding or blind embossing intaglio printing. Of course, combinations of printing methods can be used.

As printing inks any printing inks can be used, but preferably effect colors are used, which give the printed image due to their physical properties an additional protection against counterfeiting and are difficult to imitate. The printed effect layer may in particular consist of metal, a metallic color or a color containing interference layer pigments and be bronze, copper, silver or gold.

A color mixture which has a mixture component which absorbs the laser radiation and a mixture component transparent to the laser radiation can also be used as the printing ink. The laser marking of the printed image is then visually recognizable due to a laser-induced irreversible change in the optical properties of the color mixture. In particular, under the action of the laser radiation, the absorbent mixture component can be bleached, vaporized, changed in its reflection properties or converted by a chemical reaction into a material having different optical properties.

In particular, optically variable liquid-crystal pigments and, for the absorbing mixture component, optically variable interference-layer pigments are suitable as the mixture component transparent to the laser radiation. Other color components that are irreversible in their optical properties, such as an intaglio printing ink, a metallic effect ink or metallic pigments, a luminescent color or luminescent pigments, luster pigments or a thermochromic color, are also suitable for the absorbing mixture component.

The printed image can also consist of several superposed color layers, wherein at least one of the color layers for the laser radiation is absorbent or contains absorbing components. The visual design of the printed image can thereby be decoupled from the requirements of the laser beam absorption.

The layers arranged above an absorbing ink layer can be removed during laser marking. In the printed image, for example, a liquid crystal layer over an infrared-absorbing Be provided pressure layer. The IR-transparent liquid crystal layer is then removed together with the IR-absorbing background layer at the laser-exposed areas.

The printed image may also contain a liquid crystal layer over a thermochromic ink layer, wherein the thermochromic ink layer is irreversibly blackened at the laser-exposed areas, so that a clearly visible dark mark is formed within the optically variable printed image.

In a particular embodiment, the printed image is oval or circular, and executed in particular in the form of a coin representation. This printed image design is preferably combined with metallic-appearing printing inks, a film patch element or a blind embossing. It makes sense that the laser marking by typical elements, such as a centered portrait or peripheral pattern, font or number representations, the coin character receives and amplified.

In other equally advantageous embodiments, the print image forms a pattern, in particular a line pattern, such as a guilloche pattern of regularly interlaced lines. Other fine-structured patterns, such as those often used in security printing, come into consideration.

The laser marking of the security element may be in the form of patterns, characters or codes. In particular, the mark can consist of alphanumeric characters, as they are usually used for serial numbers of value documents, or form a barcode, so a pattern sequence of bars and gaps, which usually a represent binary sequence of numbers. Also, two-dimensional codes that provide a particularly highly condensed record can be used. In addition, the laser marking may contain any symbols or graphic representations that may be distributed virtually without restrictions on the surface of the data carrier.

Within the laser marking or the laser modification area different laser parameters can be used to achieve different effects or different effect sizes. For example, the stroke width of a line marker or the spot size of a raster marker can be changed by focusing the laser beam. A motorized beam widening in front of the scan head or by so-called liquid lenses, the focus can be changed at the required high speed. Due to different laser power, semitransparent areas can be created next to areas with completely eroded ink. With appropriate laser power and a foaming of the substrate is possible, which can lead to an easily recognizable tactility. The modulation frequency of the laser or the pulse train in pulse mode can also be varied.

As already explained, its visual appearance is advantageously modified by the action of the laser beam in the overlapping area of laser marking and printed image. In at least one of the overlapping areas of the laser marking and the laser modification area with the printed image, its printing ink can be partially or completely removed by the action of the laser beam. For example, a partial erosion can lead to brightened, bleached or semi-transparent areas within the printed image with reduced thickness of the ink layer. The partial ablation can also be in the introduction of a feinziselierten Pattern exist, for example, forms a decorative edge around the printed image. Likewise, the optical properties of the printed image in at least one of the overlapping regions can be irreversibly changed.

According to the invention, the data carrier is not changed visually outside the overlapping area of the laser modification area and printed image. The effect of the laser modification is then limited to the area of the printed image. Alternatively, the laser parameters can be adjusted in the modification so that a tactile marking with a relief structure is generated in the data carrier outside the overlapping region of the laser modification region and printed image.

In one embodiment of the invention, below the printed image, a color layer, in particular a security color layer, is provided, which is exposed, activated or deactivated by the action of the laser beam in at least one of the overlapping areas. For the security color layer, for example, up-conversion substances, phosphorescent, fluorescent or other luminescent substances, magnetic colors, thermoelectric electroluminescent colors, but also colors that absorb outside of the visible spectral range are possible. In this way, machine-readable features can be introduced individually together with the laser marking or the laser modification. The security colors can be used to further check if the element is a laser-marked security element.

1. a) ein Druckbild auf ein Datenträgersubstrat aufgedruckt wird,
2. b) durch Einwirkung eines Laserstrahls eine das Druckbild zumindest teilweise überlappende Lasermarkierung erzeugt wird, und
3. c) durch Einwirkung eines Laserstrahls passerhaltig mit der Lasermarkierung ein das Druckbild zumindest teilweise überlappender Lasermodifikationsbereich erzeugt wird, in dessen Überlappungsbereich mit dem Druckbild das visuelle Erscheinungsbild des Druckbilds modifiziert wird.

The invention further includes a method for producing a data carrier with a security element, in which

1. a) a printed image is printed on a data carrier substrate,
2. b) by the action of a laser beam, the print image is at least partially overlapping laser mark is generated, and
3. c) by the action of a laser beam passerhaltig with the laser marking a print image at least partially overlapping laser modification region is generated in the overlap region with the printed image, the visual appearance of the printed image is modified.

The laser modification region is generated in the form of a circumferential contour of predetermined width around the edge of the printed image. The laser marking is produced in step b) with certain register variations between the printed image and the laser marking, and the laser modification region is generated in step c) with a predetermined width of the circumferential contour that is matched to the size of the register fluctuations.

Laser marking and the laser modification area are advantageously produced in the same operation with the same laser marker so that they are in perfect register with each other.

The laser marking and the laser modification area can be generated in any order. In some embodiments, however, it is advantageous if initially the laser modification region is generated, and the laser marking is then formed at least partially within the laser modification region.

The laser marking and the laser modification region are preferably generated for a plurality of individual uses on data carriers on a sheet or a roll.

1. a) ein erstes Druckbild auf ein Datenträgersubstrat aufgedruckt wird,
2. b) ein zweites Druckbild auf das Datenträgersubstrat aufgedruckt wird, wobei die beiden Druckbilder gewisse Passerschwankungen aufweisen, und
3. c) durch Einwirkung eines Laserstrahls ein die beiden Druckbilder zumindest teilweise überlappender Lasermodifikationsbereich erzeugt wird, in dessen Überlappungsbereich mit den Druckbildern das visuelle Erscheinungsbild des jeweiligen Druckbilds modifiziert wird.

The invention further includes a method for producing a data carrier with a security element, in which

1. a) a first printed image is printed on a data carrier substrate,
2. b) a second printed image is printed on the data carrier substrate, wherein the two printed images have certain Passerschwankungen, and
3. c) the action of a laser beam generates a laser modification region which at least partially overlaps the two printed images and in whose overlapping region with the printed images the visual appearance of the respective printed image is modified.

The laser modification region in step c) is generated in this case with a shape and size that is matched to the size of the register variations, according to claim 15.

For the purposes of the invention, the first or second printed image can be produced by any suitable printing method, in particular with the above-mentioned, under a printed image also a blind embossing, preferably generated in non-inked intaglio, should be understood.

1. a) ein Gesamtdruckbild auf den Bogen oder die Rolle aufgedruckt wird, das die Druckbilder mehrerer Einzelnutzen umfasst,
2. b) die Position der Druckbilder auf dem Bogen oder der Rolle erfasst wird, und
3. c) auf Grundlage der erfassten Position der Druckbilder durch Einwirkung eines Laserstrahls Lasermarkierungen in den Einzelnutzen erzeugt werden.

In a further aspect, the application includes a method for producing a plurality of individual data carriers on a sheet or a roll, in which

1. a) an overall print image is printed on the sheet or roll comprising the print images of a plurality of individual uses,
2. b) the position of the printed images on the sheet or roll is detected, and
3. c) on the basis of the detected position of the printed images by the action of a laser beam laser markings are generated in the single-use.

In a preferred embodiment of the method, register marks, in particular pass lines or register marks, are printed on the sheet or roll in step a) together with the printed images whose positions in step b) are recorded as a measure of the position of the printed images.

In one variant, an associated registration mark is printed for each printed image, the position of which is detected in step b) as a measure of the position of the associated printed image. The detection can be done only in one spatial direction, such as the direction of movement of the sheet or the role, or in two spatial directions. In the latter case, passport marks are advantageously used as pass marks, in the first case pass lines suffice.

According to another variant, an associated registration mark is printed in each case for a group of printed images, for example for a payload line, whose position in step b) is used as a measure of the position of the printed images of the assigned Group is detected. The lower cost, however, is faced with a lower detection accuracy.

The position of the registration marks in step b) can advantageously also be detected by imaging sensors, in particular by line scan cameras or area cameras.

Alternatively, in step b), the imaging sensors can also detect the positions of the printed images from characteristic features of the printed images, ie without the use of registration marks. In this case, in addition, data of the print images can be read by the imaging sensors in step b) and the information content of the laser marking can be determined on the basis of these data. In step c), laser markings with information content determined in this way are then generated in the individual components.

As laser source for the marking or modification of the printed image, an infrared laser in the wavelength range of 0.8 .mu.m to 3 .mu.m, in particular a Nd: YAG laser is used with advantage. In order to account for the high processing speeds in the printing of securities, the laser beam in marking becomes expedient at a speed of more than 1000 mm / s, preferably more than 2000 mm / s, more preferably about 4000 mm / s or more over the backing substrate guided.

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 nach einem Ausführungsbeispiel der Erfindung, die mit einem Sicherheitselement in Form einer Münze versehen ist,

Fig. 2

in (b) ein erfindungsgemäßes Sicherheitselement in schematischer Darstellung und in (a) einen Zwischenschritt bei seiner Herstellung,

Fig. 3 bis 5

weitere Ausführungsbeispiele erfindungsgemäßer Sicherheitselemente mit perfektem Passer zwischen Druckbild und Lasermarkierung,

Fig. 6

einen Bogen mit einer Mehrzahl an Einzelnutzen und eingezeichneten Abständen der geplanten Lasermarkierungen, zur Erläuterung eines erfindungsgemäßen Verfahrens,

Fig. 7

in (a) bis (c) drei Schritte beim Ausgleich der Passerschwankungen zweier Druckbilder eines Sicherheitselements mithilfe eines Lasermodifikationsbereichs,

Fig. 8

ein Blockschaltbild zur Erläuterung eines erfindungsgemäßen Verfahrens, beim welchem die Positionen der Druckbilder sensorisch erfasst werden,

Fig. 9

eine schematische Darstellung eines Vektor-Laserbeschrifters zur Erläuterung dessen Arbeitsprinzips,

Fig. 10

eine schematische Darstellung eines Vektor-Laserbeschrifters zur Beschriftung eines Wertpapierbogens,

Fig. 11

einen Ausschnitt eines Wertpapierbogens mit einer Mehrzahl an Einzelnutzen und mit Passlinien bei jeder Nutzenzeile, und

Fig. 12

einen Ausschnitt eines Wertpapierbogens wie in Fig. 11 mit Passkreuzen an jedem Einzelnutzen.

Show it:

Fig.1

a schematic representation of a banknote according to an embodiment of the invention, which is provided with a security element in the form of a coin,

Fig. 2

in (b) a security element according to the invention in a schematic representation and in (a) an intermediate step in its manufacture,

Fig. 3 to 5

further embodiments of security elements according to the invention with perfect registration between print image and laser marking,

Fig. 6

a sheet with a plurality of individual uses and marked distances of the planned laser markings, to explain a method according to the invention,

Fig. 7

in (a) to (c) three steps in the compensation of the register fluctuations of two printed images of a security element by means of a laser modification area,

Fig. 8

a block diagram for explaining a method according to the invention, in which the positions of the printed images are detected by sensors,

Fig. 9

a schematic representation of a vector laser marker for explaining its working principle,

Fig. 10

a schematic representation of a vector laser marker for labeling a security sheet,

Fig. 11

a section of a security sheet with a plurality of individual benefits and with pass lines for each pay line, and

Fig. 12

a section of a security sheet as in Fig. 11 with registration marks on each individual use.

The invention will now be explained using the example of a banknote. Fig. 1 shows a schematic representation of a banknote 10, which is provided with a security element 12 in the form of a coin. The security element 12 has a circular printed image 14, which is printed by means of screen printing technique with a metallic color, such as a silver color, on the banknote substrate.

The security element 12 is further provided with a laser marking 16, for example a serial number, which runs along the curve of the printed image 14. In order to increase the coin character of the security element 12, it is typically provided with additional graphic motifs or alphanumeric elements which are incorporated in US Pat Fig.1 are not shown. The laser-generated motifs of the coin 12 can be repeatedly applied to the banknote to increase the security against counterfeiting with other techniques, for example as a steel engraving motif or as a watermark.

In visual appearance, the printed image 14 and the laser marking 16 are in perfect register with each other. The invention provides two ways to achieve this Passerhaltigkeit.

First, the procedure according to the first aspect of the invention with reference to the FIGS. 2 to 6 explained. Fig. 2 shows in (a) a security element 20 with an oval printed image 22, which is provided with a laser marking 24. Because of the above-described register fluctuations between the print image and the laser marking, the alphanumeric marking 24 does not exactly follow the rounding of the print image 22. Although the magnitude of the deviation in Fig. 2 (a) is shown exaggerated for illustration, the human eye is very sensitive to such deviations, especially in round or rounded elements, so that even relatively small deviations can emerge disturbing.

According to the invention, therefore, the security element, as in Fig. 2 (b) shown, additionally provided with a print image partially overlapping laser modification region 26, which forms a peripheral edge of the print image 22 contour. In the overlap region 28 of the laser modification region 26 with the printed image 22, the printing ink of the printed image is removed or converted into a transparent modification. The laser modification region 26 stands in the perfect register to the laser marking 24, since it is generated with this in the same operation by the same laser marker and controlled by the same computer. The removal of the ink can be done by the laser beam is directed directly to the ink and from the side on which the ink is applied. Alternatively, the laser beam can also act on the rear side, ie on the surface of the substrate facing away from the printing ink, and achieve the desired effects on the side of the substrate on which the printing ink is located.

When considering the completed security element 20 of the Fig. 2 (b) visually gives the impression of a perfect laser marking passport 24 and the still visible part of the printed image 22. Such a perfect passport with rounded elements is a for forgers very difficult to overcome hurdle and forms, precisely because of the mentioned sensitivity of the human eye for small Passerschwankungen, a security element of high security against counterfeiting.

The order in which the laser marking 24 and the laser modification region 26 are generated is basically arbitrary. As explained below, it may be advantageous, depending on the desired effect, first to generate the laser marking 24 or first the laser modification region 26.

The print image 22 to be provided with the laser marking can be exposed or surrounded by adjacent print images. In the latter case, it is advantageous if the printing inks of the adjacent printed images for the laser radiation are transparent, so that depending on the laser parameters used in the generation of the laser modification region 26 there is no or a tactile mark.

The FIGS. 3 to 5 show further embodiments of security elements according to the invention with perfect registration between print image and laser marking. Like the embodiment of Fig. 3 shows, in the same reference numerals as in Fig. 2 Denote the same elements, the principle described can also be applied to security elements 20 with complicated shapes. Instead of removing the printing ink completely in the overlapping area 28, a decorative edge 28 can also be generated around the printed image 22 by suitable control of the laser writer. Visually dominates the full-surface interior of the printed image, so that here too the impression 22 of a perfect pass between printing image and laser marking.

The laser marking 24 can, as in the embodiment of the Fig. 4 also be led beyond the edge of the printed image 22, where it causes a marking effect in the data carrier substrate, such as a blackening 30. As a result, special contrast effects can be generated. For example, the overlapping with the print image 22 marking part 32, in which only the ink is removed and the remaining laser energy is not sufficient to blacken the substrate, white against the silver or gold-colored background of the print image 22, while the laser action outside the print image 22 to a Blackening 30 of the otherwise bright substrate material leads.

In designs having laser markings extending beyond the edge of the print image, the laser modification region is advantageously first created to ensure that the location of the contrast or color change coincides with the edge of the remaining print image.

At the in Fig. 5 represented further variant of the invention, the impression of a registration of printed image and laser marking is created by the fact that in the print image or in the substrate of the data carrier with a first parameter set of the laser writer a two-dimensional change is created, and then in the thus generated laser modification region with a second parameter set passerhaltig a laser marking is produced with a different from the area change effect. The planar change may, for example, consist in a removal of paint or color components, a whitening or bleaching. In the in Fig. 5 (a) In the exemplary embodiment shown, the line pressure pattern 40 is lightened in the laser modification region 42 and, in the register, a tactile marking 44 is produced at a significantly higher laser intensity. Like the embodiment of Fig. 5 (b) shows the planar change 42 in the print pattern 40 can also leave a print image area 46, in which then the laser marking 44 is generated.

As already under Fig. 2 explained, the laser beam can be performed on the front as well as on the back of the substrate.

Regarding Fig. 6 For example, in the manufacture of a plurality of individual bins 10 on a sheet 50 or roll, the laser process is initiated once per sheet or roll. If the start signal is given at the upper left corner of the arc, the distances 52 (in the x-direction) and 56 (in the y-direction) lead to the security element of the first banknote to be marked. In a signature, the distances 54-i, i = 1 ... 3 (in the x-direction) and 58-j, j = 1 ... 6 (in the y-direction) between the security elements to be marked are constant, the generation The laser markings and the laser modification areas then take place at predetermined fixed distances 54 and 58, respectively. The accuracy of the lasering in relation to the printed image is of the same order of magnitude as in a conventional digitization. However, since the laser marking is placed visually in relation to the laser modification area generated in the same working step, practically no register fluctuations can be recognized by the viewer.

For the trained eye or with the help of optical devices, however, it can be proved beyond doubt, for example by means of binder residues, that the security element has been provided with a laser-generated register is. Also, substances that are invisible to the human eye can be introduced into the print layer or an underlying layer. The presence or absence of a laser modification can thus serve as an additional security feature.

If necessary, the coordinates of the elements to be marked can also be detected more accurately. For example, the distances 54-1, 54-2, 54-3 ... (in the x-direction) and 58-1, 58-2, 58-3 ... (in the y-direction) between the elements to be marked of the sheet are determined individually on the quiescent sheet and entered into the laser scribe control unit to compensate for changes in the length and / or width of the sheet 50. The position measurement can be carried out individually for rows and rows or even for each benefit, whereby spacings 52-i, 54-i1, 54-i2, 54-i3,..., For the i-th payload line in x- Direction, and distances 56-j, 58-j1, 58-j2, 58-j3, ..., for the j-th benefit series in y-direction.

The procedure described above can also be used according to the invention for producing a data carrier with a security element having two print images, in which the two print images initially have certain register fluctuations.

Fig. 7 shows in (a) two successively printed on a data carrier substrate printed images 60 and 62 with Passerschwankungen 64. By the action of a laser beam, the two print images 60, 62 overlapping laser modification region 66 is generated in its overlap region 68 with the print images, the ink of the respective print image 60th or 62 is removed, as in Fig. 7 (b) shown. The laser parameters are chosen so that the data carrier substrate outside the overlap area 68 is not changed. Remains thus in the Fig. 7 (c) It will be understood that this method can also be applied to more than two printed images. The printed images can be applied to the front and / or back.

In the further aspect, registration variations between the printed images of a sheet or a roll and the respective laser marks are avoided by sensing the positions of the printed images or certain elements of the printed images, and generating the laser marks based on the detected positions.

The basic procedure is in the block diagram of Fig. 8 illustrated. The process begins at reference numeral 80, where sheet feeding into the machine occurs. The sheets 82, each containing a plurality of individual utilities on data carriers, are processed at a given web or bow speed 84. For example, the speed is about 10,000 sheets / hour, which, depending on the embodiment, corresponds to web speeds of 2 m / s to about 3.5 m / s. Such web speeds are also achieved when processing web-shaped materials. The coordinates of preprinted registration marks or specific locations in the printed image of the individual items are detected (reference numeral 86) and forwarded to a computing unit 88 for determining the marking positions. The arithmetic unit 88 drives a laser scribe 90, described in more detail below, to apply the laser marks in the correct positions within the print image of each individual use. Lastly, the marked sheets are output at reference numeral 92.

Fig. 9 schematically shows the scan head 100 of a vector laser marker, with which the security element 102 of a single use with a laser marking 104 is provided. An infrared laser beam 106 is deflected by two movable mirrors 108, one of the mirrors producing the deflection in the x direction, the other mirror generating the deflection in the y direction. A plan field lens 110 focuses the laser beam 106 onto the security element 102, where it generates the laser marking 104 and optionally also a laser modification region in the manner described above.

The security element 102 with the data carrier substrate moves at a certain speed v during the marking process. This speed is detected by sensors (reference numeral 84 in FIG Fig. 8 ) and to the computer 88 ( Fig. 8 ) to control the movement of the mirrors 108 to compensate for the substrate velocity v in the label. The marking method can therefore be used particularly advantageously for contactless identification of documents of value, which are processed at high speeds, as usual in printing shops.

The security elements 102 of a sheet can, for example, also be marked by means of a matrix of punctiform emerging laser beams or by means of beams of larger cross-section, which are partially covered by a template. Such templates can be executed automatically changeable. If entrainment of the radiation in accordance with the substrate speed is not possible or undesirable, identification of moving substrates is also possible by selecting a short exposure time. Also the beam guidance by polygon mirror is possible.

Depending on the substrate used, sources of radiation include CO ₂ lasers, Nd: YAG lasers or other laser types in the wavelength range from UV to to the far infrared in question, the laser often work also advantageous with frequency doubling or tripling. Preferably, however, laser sources are used in the near infrared, since this wavelength range fits well with the absorption properties of the data carrier substrates and printing inks used. Depending on the application, the spot size of the laser radiation can be varied from a few micrometers to a few millimeters, for example by changing the distance between the plane field lens 110 and the security element 102. Spot sizes of around 100 μm are preferably used.

The continuous power of the laser inscribers used is typically between a few watts and a few 100 watts. Nd: YAG lasers can be operated with laser diodes for lower overall power with smaller dimensions and high beam quality, or with pump lamps for high output. In order not to reduce the speeds of an industrial production line of value documents, the laser markings or laser modifications are advantageously carried out with very fast moving galvanometers, which guide the beam at more than 1000 mm / s, preferably up to 4000 mm / s and more across the substrate can. At these marking speeds, only a small proportion of energy is deposited per distance in the substrate or the security element 102, so that advantageous lamp-pumped Nd: YAG lasers with a power of about 100 watts are used.

By varying the labeling parameters, such as the laser power, exposure time, spot size, labeling speed, working mode of the laser, etc., the marking results can be varied widely. Thus, by the laser in addition to the partial or complete removal or the partial or complete modification of color or effect layers also other markings, such as blackening in the data carrier substrate, or even tactile markings are generated with a relief structure. Such tactile markings preferably have a height of 30 to 100 microns.

The markings are made, for example, with an Nd: YAG laser whose fundamental wavelength is 1064 nm and which has an average power of 26 W and a modulation frequency of 8 kHz. The diameter of the laser beam on the substrate (spot size) is about 100 microns and the travel speeds of the laser beam over the substrate 250 to 4000 mm / s.

Fig. 10 shows a laser marker 120 in which a sheet 122 is provided with a plurality of lasers simultaneously with a laser mark and a laser modification area. In the example shown, the sheet 122 has six columns and six rows, so that 36 single-use 124 are arranged on bills or other data carriers on this sheet. For each column, a laser tube 126 is arranged above the printed sheet 122 and, together with the associated scanning head 128, generates the laser markings or modifications in the individual slots 124 arranged in this column. By this arrangement, the throughput can be greatly increased, since not a single laser beam must be moved over the entire sheet, but only a scan field between the columns of the sheet is applied. The application of the individual benefits takes place as with Fig. 9 described about the deflection of the laser radiation by means contained in the scan heads 128 mirrors.

An embodiment for detecting the position of the print images of the single-use will now be with reference to Fig. 11 explained. For the following description For example, the y-coordinate along the row direction of the single-use, the x-coordinate along the row direction is selected.

As in Figure 11 1, an associated registration line 136 is printed on the sheet 130 for each row of single-use 132 with print images 134 to be marked. A print mark or contrast mark sensor detects pass line 136 before laser marking and controls the y coordinate of the mark accordingly. The pass line 136 is printed in the printing process to be appropriately lasered so that it is subjected to the same registration variations as the print images 134 of the utility line. If the print sheet is changed in the row direction in its length, for example by drying or rolling, this can be taken into account and compensated for by the detection of the position of the pass lines 136 for the associated print images 134.

In this case, an assigned pass line can also be printed for each individual benefit. The pass lines can then be individually recorded and evaluated for each benefit row, whereby a higher accuracy is achieved in non-uniform change of the y-coordinate over the row direction x, for example by non-uniform drying or trapezoidal Auswalzung.

Instead of the pass lines, it is often possible to use prominent locations in the print image of the data carriers for the acquisition. The individual benefits can then be arranged space-saving on the sheet.

Fig. 12 shows a sheet 140, in which for each individual use 142 an associated registration cross 146 is printed. This allows the position of the print images 144 in the row direction x to be determined in addition to the y coordinate. In order to be able to use a contrast mark sensor here as well, the scanning light beam can be guided, for example, by means of a polygon wheel transversely to the direction of movement of the sheet, the smallest possible trajectories are selected to avoid inaccuracies.

The scanning in the x-direction, but also in the y-direction, can also be carried out with the aid of imaging sensors, for example with a CCD or CMOS line scan camera. The image refresh rate of such sensors is high enough to be able to record each individual benefit despite the high web speeds. For the detection of registration marks 146 or significant points in the print image 144, one row per benefit row is advantageously used, as indicated by the dashed line scan cameras 150 in FIG Fig. 12 indicated.

The read-out single lines can either be processed directly, or assembled into pictures with the aid of a clock, which is determined by the speed measurement of the sheets, and then evaluated. The evaluation is done with special hardware and / or software, in particular digital signal processors and PGA (Programmable Gate Array) - modules are suitable. Because of the short shutter speeds required, it is advisable to have very bright and well-adjusted lighting, such as flashlamps, synchronized with the image input.

Instead of line scan cameras 150 it is also possible to use surface cameras which receive two-dimensional information. In this way, the printed image of the overall appearance can be detected. In order to achieve a high resolution and thus a good accuracy of the registration, it also makes sense here to use a surface camera per benefit row. In particular, here offer CMOS cameras, as these at high resolution achieve high repetition rates and support fast signal processing well. Otherwise, the above statements apply with regard to the signal processing and the illumination.

Since area cameras capture the entire print image, less prominent points can be found in the print image and used as a basis for determining the position. The downstream data processing is then easier to realize. In addition, the captured images can serve to quality control previous print runs.

In the variants in which imaging sensors are used for position determination, they can additionally read data of the printed image, which determine or co-determine the information content of the laser marking.

For example, a camera may read a letter-printed number sequence of the print image and the read data may be used to generate a corresponding matrix code of equal information content and to introduce it as a laser mark into the print image of that single benefit. Also, the information content of the laser mark can only be derived from the read information content, and for example, represent a check digit for the read digit, or repeat part of the read digit.

Claims (23)

1. A data carrier having a security element (20) that exhibits a print image (22) and a laser marking (24) at least partially overlapping the print image, certain register variations existing between the print image and the laser marking, characterized in that the security element exhibits, in addition to the laser marking, at least partially overlapping the print image, a laser modification area (26) that is in register with the laser marking and in whose overlap area (28) with the print image the visual appearance of the print image is modified by the action of a laser beam, wherein the data carrier is not visually changed outside of the overlap area of the laser modification area, wherein the print image and the laser marking and the laser modification area do not coincide, the laser modification area forming a contour of predefined width surrounding the edge of the print image, and where the predefined width of the surrounding contour is matched to the size of the register variations between the print image and the laser marking, such that all typically occurring register variations can be compensated for and when the finished security element is viewed, the visual impression of perfect register of the laser marking and the still visible portion of the print image results.
2. The data carrier according to claim 1, characterized in the print image is imprinted by means of screen printing, offset printing or relief printing.
3. The data carrier according to claim 1 or 2, characterized in that the print image is an effect layer.
4. The data carrier according to claim 3, characterized in that the effect layer consists of metal, a metallic ink or an ink containing interference layer pigments.
5. The data carrier according to claim 3 or 4, characterized in that that the effect layer is bronze, copper, silver or gold colored.
6. The data carrier according to at least one of claims 1 to 5, characterized in that the print image is designed as an oval or circle, especially in the form of a coin likeness.
7. The data carrier according to at least one of claims 1 to 6, characterized in that the print image forms a pattern, especially a line pattern, such as a Guilloché pattern.
8. The data carrier according to at least one of claims 1 to 7, characterized in that the laser marking is designed in the form of patterns, characters or codes.
9. The data carrier according to at least one of claims 1 to 8, characterized in that, in the overlap area of the laser marking and the print image, the visual appearance of the print image is modified by the action of a laser beam.
10. The data carrier according to at least one of claims 1 to 9, characterized in that in at least one of the overlap areas of the laser marking and the laser modification area with the print image, the printing ink of the print image is partially or completely ablated by the action of a laser beam.
11. The data carrier according to claim 10, characterized in that the print image is lightened or bleached in at least one of the overlap areas.
12. The data carrier according to claim 10 or 11, characterized in that the optical properties of the print image are irreversibly changed in at least one of the overlap areas.
13. The data carrier according to at least one of claims 1 to 12, characterized in that, outside the overlap area of the laser modification area and the print image, the data carrier exhibits a tangible marking having a relief structure.
14. The data carrier according to at least one of claims 1 to 13, characterized in that below the print image is provided an ink layer, especially a security ink layer, that is exposed, activated or deactivated in at least one of the overlap areas by the action of the laser beam.
15. A method for manufacturing a data carrier having a security element (20), in which

    a) a print image (22) is imprinted on a data carrier substrate,

    b) a laser marking (24) at least partially overlapping the print image is created by the action of a laser beam, certain register variations existing between the print image and the laser marking, and

    c) in addition to the laser marking, by the action of a laser beam is produced, in register with the laser marking, a laser modification area (26) at least partially overlapping the print image and in whose overlap area (28) with the print image the visual appearance of the print image is modified, wherein the data carrier is not visually changed outside of the overlap area of the laser modification area and the print image, wherein the laser marking and the laser modification area do not coincide,

    wherein the laser modification area is produced in the form of a surrounding contour of predefined width around the edge of the print image, and wherein the laser marking is produced in step b) having certain register variations between the print image and the laser marking, and the laser modification area is produced in step c) having a characteristic dimension that is matched to the size of the register variations, such that all typically occurring register variations can be compensated for and when the finished security element is viewed, the visual impression of perfect register of the laser marking and the still visible portion of the print image results.
16. The method according to claim 15, characterized in that the print image is imprinted by means of screen printing, offset printing or relief printing.
17. The method according to claim 15 or 16, characterized in that the laser marking and the laser modification area are produced in the same operation with the same laser marker.
18. The method according to at least one of claims 15 to 17, characterized in that the laser marking and/or the laser modification area are produced with varying laser beam parameters such that different effects or different effect intensities are achieved.
19. The method according to at least one of claims 15 to 18, characterized in that the laser modification area is first produced, and the laser marking is then produced at least partially within the laser modification area.
20. The method according to at least one of claims 15 to 19, characterized in that the laser marking and the laser modification area are produced for a plurality of individual ups of data carriers on a sheet or a roll.
21. A method for manufacturing a data carrier having a security element, in which

    a) a first print image (60) is imprinted on a data carrier substrate,

    b) a second print image (62) is imprinted on the data carrier substrate, the two print images exhibiting certain register variations (64), and

    c) by the action of a laser beam, a laser modification area (66) at least partially overlapping the two print images is created in whose overlap area (68) with the print images the visual appearance of each print image is modified, wherein the data carrier substrate is not visually changed outside of the overlap area of the laser modification area and the print images, the laser modification area running alongside the edge of the two print images, with the laser modification area having been produced having a shape and size that are matched to the size of the register variations, such that a registered transition between the two print images results.
22. The method according to at least one of claims 15 to 21, characterized in that, to produce the laser marking and/or the laser modification area, an infrared laser in the wavelength range from 0.8 µm to 3 µm, especially a Nd:YAG laser, is used.
23. The method according to at least one of claims 15 to 22, characterized in that, for marking, the laser beam is guided across the data carrier material at a speed of more than 1000 mm/ s, preferably of more than 2000 mm/ s, particularly preferably of 4000 mm/s or more.

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