EP2315669B1 - Data carrier comprising a printed magnetic security feature - Google Patents

Description

The invention relates to a data carrier with a printing technology applied, magnetic security feature and a manufacturing method for such a disk.

To ward off counterfeiting attempts is for media of any kind, such as banknotes, stocks, bonds, certificates, vouchers, checks, lottery tickets, high-quality tickets, passports, ID cards and other counterfeit papers, and card-shaped media, especially smart cards, a constant need for new security features ,

In the WO 2006/053685 A2 a banknote is described with a banknote-specific code not visible to the viewer. This is, for example, a barcode printed with an ink visible only in the infrared. The banknote-specific code is derived from a measurable characteristic of the banknote, for example from a pattern introduced by means of a laser or from another deliberately varied or random feature of the banknote, such as from a gravure printing element printed on the banknote.

Likewise describes the WO 2007/110155 A1 a security element, which is only visible in the infrared and therefore not visible to a viewer. The banknote described therein comprises an upper protective layer which does not absorb infrared laser light and a lower marker layer which absorbs the laser light. By means of short IR laser pulses, information which is not visible to the observer can thereby be written into the lower marking layer without destroying the upper covering layer.

Out DE 10 2007 055 112 A1 is a so-called "washing process" is known in which in a coating in incident light recognizable characters are introduced by applying a printing ink under the coating, which consists of a mixture of a binder and reactive components. Upon contact with water and / or by irradiation, the reactive components are activated and break up the coating. It is further stated that, together with the printing ink , the overlying coating or all coatings lying above the printing ink are also removed.

Object of the present invention is to provide an alternative method for producing a data carrier with a non-visible to the viewer, machine-readable security feature and a corresponding disk.

This object is achieved by a method and a data carrier having the features of the independent claims. The dependent claims and the following description relate to preferred embodiments and further developments.

The present invention relates to inks with a magnetic component and is based, inter alia, on the recognition that the amount of magnetic substance in such a printing ink can be reduced after printing on a data carrier. Both the amount by which the amount of the magnetic substance is reduced, as well as the affected spatial area can be specifically selected.

The security feature is thus generated by printing a printing ink on the data carrier which contains a selected amount of a magnetic substance in a first step. In a further step, the amount of the magnetic substance of the printing ink is reduced in at least a portion of the printed ink.

The ink comprises, mixed with a base ink for the applied printing process, such as high-pressure, gravure, offset, screen, digital, indirect, flexo, thermal, laser, ink jet, dot matrix, magnetic paste with para and / or ferromagnetic particles. The ink is thus magnetizable and generates in the case of ferro-magnetic particles magnetization, which persists even without external magnetic field and produces a so-called remanence flux density. The magnetic particles may be hard or soft magnetic. The magnetization can be detected mechanically by magnetic sensors.

The printed ink covers the disk at least partially, that is, the disk is partially or completely printed with the security feature.

Following the printing of the magnetic printing ink, the amount of the magnetic substance contained therein is at least partially reduced by removing or extinguishing the magnetic particles. This reduces the magnetic polarizability, that is the achievable magnetization, in the corresponding subregion. In the case of ferromagnetic particles thus the remanence flux density is reduced. Preferably, the amount of the magnetic substance is reduced to 10 to 50% of the original amount. The amount of magnetic substance is thus, after reducing, both from the amount of the magnetic substance before reducing and from zero different, wherein these different amounts of the magnetic substance can be measured with appropriate sensors each. The data carrier produced by the production method according to the invention accordingly has an altered magnetic structure, which is subsequently detectable. As a result of this partial change of the magnetic property in at least one subregion of the printed magnetic printing ink, a clearly distinguishable machine-readable security feature is thus created.
The thickness of the print job of the printed ink is preferably not changed by reducing the amount of the magnetic substance.
The printed magnetic ink may be in the form of a single printing element or in the form of a plurality of spatially separated printing elements. The one or more printing elements can be formed over the entire surface or as a grid. The subregion in which the amount of magnetic substance is reduced can then be a subarea of such a printing element or, in the case of a plurality of printing elements, can comprise one or more printing elements completely. As a result, an altered magnetic structure, for example in the form of alphanumeric characters and / or graphic elements, can be created on the data carrier. Through this form of intelligent magnetic coding, the security feature of the data carrier can be marked and individualized.

The production method according to the invention thus provides a machine-readable security feature for a data carrier whose presence is not recognizable to the viewer and thus also to a potential forger, and which consequently lacks in forgeries. The security feature can be, however, with suitable test equipment, which at least in Banks or even at a point-of-sale, such as a cash register, are present, check.

Another advantage of the magnetic properties used according to the invention is that they are not influenced by contamination of the data carrier and are therefore superior to optical security features.

The magnetic ink can be printed directly on the disk or, for example, on a carrier film to produce a transfer element, which is then applied to the disk.

In an advantageous embodiment of the manufacturing method according to the invention, the reduction of the amount of the magnetic substance takes place by interaction of the printed ink with the radiation of an electromagnetic radiation source, in particular with the radiation of a laser. The magnetic particles of the magnetic paste, which is part of the ink, are highly suitable for being removed from the printed ink using such electromagnetic radiation. By the action of the electromagnetic radiation, the magnetic particles are preferably evaporated and / or thrown out. This happens even with a very low radiation or laser power.

Preferably, the base color and the wavelength of the laser are chosen such that the base color is transparent to light of the wavelength of the laser, so that the base color does not or only to a small extent absorb the laser light. This allows the magnetic particles using the laser are targeted, while the base color in the print order is not or only slightly changed.

The radiation source used is preferably short-time pulse lasers, such as Nd: YAG or Nd: YVO ₄ lasers with a wavelength of 1.064 μm, which deliver pulse lengths in the range from 1 to 50 nanoseconds. The use of pulsed short-term lasers helps to avoid unwanted changes to the security feature and also to the data carrier. By using a laser to reduce the amount of magnetic substance in the printed ink, high spatial resolution of the portions having the changed magnetic property can be obtained. This spatial resolution is determined by the size of the interaction region of the electromagnetic radiation and preferably corresponds to the size of the laser focus.

wobei gilt ΔL = L₁ - L₂, ΔA = A₁ - A₂ und ΔB = B₁ - B₂. In diesem wahrnehmungsangepassten Farbraum steht ein bestimmter Farbabstand ΔE für einen bestimmten subjektiv durch einen Betrachter empfundenen farblichen Unterschied zweier Farbtöne.The change in the magnetic properties may be accompanied by a color change that should remain as inconspicuous as possible. The color change or the color change of the subarea with the changed magnetic property can be characterized by means of the perception-adapted LAB color space. Each hue is assigned a unique value triplet L, A, B , with the L value between 0 and 100 and the A and B values between -128 and +127, respectively. The color difference .DELTA.E of two colors (L _1, A _1, B ₁₎ and (L _2, A _2, B ₂₎ is calculated from the Euclidean distance measure $\sqrt{\mathrm{\Delta }{L}^{}}$$\sqrt{{}^2+\mathrm{<figure-callout\; id="2"\; label="\Delta \; A"\; filenames="imgf0001.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{A}^{}{}^2+\mathrm{<figure-callout\; id="2"\; label="\Delta \; B"\; filenames="imgf0001.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{B}^{}{}^2}.$

where ΔL = L ₁ -L ₂ , ΔA = A ₁ -A ₂ and ΔB = B ₁ -B ₂ . In this perception-adapted color space, a specific color difference ΔE stands for a specific subjectively perceived by a viewer color difference between two shades.

Preferably, by reducing the amount of the magnetic substance, the hue of the ink changes by a color distance of less than 25, preferably less than 15, 5, 2, or 1. With such a small color difference, the color change in the partial area in which the amount falls of the magnetic substance was reduced visually only slightly, so that the color change for the viewer, even in comparison with areas where the amount of the magnetic substance has not been reduced, hardly or not visible.

The color change can be reduced by a suitable choice of the parameters of the printing ink and / or the electromagnetic radiation source. In general, the color change in reducing the amount of the magnetic substance is small when the color tone of the magnetic paste has only a slight color difference from the base color.

In an advantageous embodiment, the printed security feature and / or the sub-area in which the amount of the magnetic substance has been reduced, laminated by patterns and / or structures in the background printing. Furthermore, the subarea can also be overprinted in a further processing step, for example with effect pigments. Such lamination is advantageous especially at higher color distances and / or if the visual perceptibility of the partial area with the changed magnetic structure is to be reduced.

In a further advantageous embodiment of the invention, a tactile perceptible element is generated by printing the ink on the disk.

The printing is done preferably in gravure printing, such as the intaglio printing, in which the engravings are introduced by means of a manually or mechanically guided stylus in the printing plate, or the screenprint, in which recesses are etched into the printing plate. The generated gravure elements are easy to check tactile without tools, but technically difficult to imitate. With gravure printing, many degrees of freedom are available to specifically influence the tactile perceptibility as well as the magnetic properties of the printed gravure element. The engraving in the printing plate for receiving the magnetic paste of the printing inks are optimized in view of the necessary signal strength of the magnetic sensors used, for example, by a sufficient dimensioning of the engraving in the printing plate in terms of depth and / or width. The smallest dimension of the engraving is at least 10 x 10 μm. The engraving preferably has a width of more than 100 μm, more preferably 1 to 3 mm. The smallest distance of several engravings in the pressure plate can be 0 μm. It is preferably 500 .mu.m, more preferably 1 to 10 mm. The flank angle of the engraving in the printing plate is preferably 40 ° (compared to the surface normal of the printing plate surface), so that the engraving depth is about half of the engraving width. The flank angle is determined for example by the corresponding angle of the stylus to produce the engraving. The engraving depths are between 0 and 250 microns, preferably between 0 and 120 microns and more preferably between 30 and 70 microns. In this case, different thickness print jobs, resulting from different deep engraving, interact differently with the laser used to reduce the amount of magnetic material. Because the near-surface magnetic particles of a thick print job are more affected by the incident laser radiation than the lower-lying particles. To increase the tactile perceptibility of the security feature has its tactile area a line structure with tactile perceptible lines in the amount of example 100 microns.

The use of the line gravure printing to produce the security feature allows the realization of integrated in the printing element tactile elements, especially in the edge region of the printing element. The provision of tactile elements increases the security against forgery, since these elements are difficult to copy, in particular not by means of a (color) photocopier, and also can be easily checked by the sense of touch.

In a further advantageous embodiment of the invention, at least one further printing ink is printed on the data carrier in order to generate a further part of the security feature. The further printing ink differs from the first printing ink in the amount of the magnetic substance which contains the further printing ink in the printing, in the hue of the printing ink and / or in the thickness of the print job.

The further printing ink differs from the first printing ink, for example in the mixing ratio of base color and magnetic paste used or in the base color used and / or the magnetic paste itself, the latter having, for example, magnetic particles with different magnetic properties. In particular, when printing in gravure printing, the thickness of the print job can be easily varied over the engraving depth of the printing plate. In addition, several magnetic pastes can be combined in one printing ink. Thus, a variety of degrees of freedom are available to impart the desired hue and magnetic properties to the printed ink. In particular, the thickness of the print job already influences the print job area-related amount of the magnetic substance in the security element and thus the magnetization or the (remanent) flux density of the print job. Since gravure paints are usually used in gravure printing, the tonal value can also be set via the ink layer thickness.

The printing of the other ink can be done in one step together with the printing of the first ink. In particular, a multicolored print is possible. In this case, the further printing ink can not only have different magnetic properties from the first printing ink, but it is also possible to omit the addition of a magnetic paste as a whole, so that a structuring of the magnetic properties of the security element is already possible when printing the various printing inks. Preferably, structures can be printed which are alternately magnetic and non-magnetic.

In a further advantageous embodiment, the magnetic properties of the various printed printing inks are characterized in that the amount of the magnetic substance is also reduced in at least one subarea of the further printing ink.

This results in further degrees of freedom for the individualization of the data carrier and for the design of the desired security feature. Preferably, the hue and / or the amount of the magnetic substance of the plurality of printed inks chosen such that after individualizing areas with different magnetizations (in terms of strength and / or type of magnetization), but same shades result, so that the areas with measurable different magnetic properties are visually hardly or indistinguishable.

Advantageously, the contours of the region of the printing ink and / or of the subregion in which the amount of the magnetic substance is reduced are selected such that the region of the ink and / or the subregion can be detected by machine with a magnetic sensor to a desired extent. A magnetic sensor generates a detection signal at the transition between regions of different magnetic flux density, for example, at the transition between a region without magnetic substance and a magnetic substance region, or between the region of the ink and a portion with a reduced amount of the magnetic substance. The strength of the detection signal depends on the time-related gradient of the magnetic flux density at the magnetic sensor, so that a stronger detection signal is generated when the security feature is moved past the magnetic sensor, for example at a higher speed, and especially if a sharp or sharp on the security feature or there is rapid transition between regions of different magnetization, in other words, if there is a strong localized gradient of the amount of magnetic material on the medium. Such a sharp transition is generated, for example, by straight edge contours of the different regions of the security element, which preferably extend transversely to the detection direction, ie transverse to the direction in which the data carrier in the detection of the magnetic properties, for example in a test method against a magnetic sensor of a corresponding Tester is moved. This detection direction is generally already known in the production of the data carrier and is generally equal to the direction of one of the edges of the data carrier or the security element. Such an orientation of the edges leads to a high detection signal in the magnetic sensor and thus reduces on the one hand the necessary amount of magnetic particles in the ink and on the other hand the necessary Detection sensitivity of the magnetic sensor, whereby the security feature and its various areas can be detected with little effort and high detection reliability.

If, on the other hand, the lowest possible detection signal of the magnetic sensor is desired in the transition between regions with different magnetization, a slow transition, that is a broad transition region with a small localized gradient of the amount of magnetic substance at the transition, is preferably generated and the transition is obscured, for example by the intensity of the electromagnetic radiation with which the amount of magnetic substance in the subregion is reduced is changed continuously or stepwise in the edge region of the subregion. As a result, during the step of reducing the amount of the magnetic substance, for example via the intensity of the electromagnetic radiation, the strength of the later detection signal of the magnetic sensor can be changed and thus the security feature of the data carrier can be further individualized. The individualization is preferably supported by a suitable choice of the contour of the area or the areas of the ink with the magnetic particles.

Advantageously, the amount of the magnetic substance in the at least one subregion is not reduced over the entire surface but only in a grid-like manner. The basic idea here is that the location-related resolution of the magnetic sensor is usually lower than the location-related resolution of the electromagnetic radiation used to reduce the amount of the magnetic substance, for example the laser focus. As a result, it is possible, for example, to generate a sharp transition which is easily detectable for the magnetic sensor, while the hue of the printing ink in the partial region is not changed visually or only slightly perceptibly. This is the Width of the interaction region of the electromagnetic radiation is preferably selected so that within the subregion a visually barely perceptible raster pattern is generated. The grid preferably comprises points or lines with a suitably chosen pattern, in particular with variable grid spacings and / or grid intensities. In a particularly preferred embodiment, the subarea has raster lines which lie in the direction of the detection direction, since thus the position of the raster lines during the detection relative to the magnetic sensor does not change and therefore the emergence of an undesired detection signal is excluded.

In a further advantageous embodiment, the amount of the magnetic substance is not reduced in the entire print order of the printing ink but only on its upper side. As a result, the amount of the magnetic substance is reduced only in a small segment of the print job, whereby the hue of the applied ink changes visually only slightly. Such reduction of the amount of the magnetic substance in only a near-surface region can be carried out very easily on a gravure printing element with a significant amount of the print job, in particular on a tactile element. Advantageously, this near-surface reduction is performed at the same time raster-like, which further reduces the visual distinctness of the portion of the area of the ink with unreduced amount of magnetic substance.

Preferably, the laser used to reduce the amount of the magnetic substance is also used for introducing further markings, for example individualizing codes, in at least one further security feature, for example in a foil element and / or a security thread, of the data carrier.

By means of the method described above, a data carrier with an imprinted security feature can be produced, which has a first and a second subregion with the same print layer thickness and the same printed ink, wherein the first subregion contains a first quantity of a magnetic substance and the second subregion contains a second, lower, contains reduced amount of the magnetic substance relative to the first portion. Other portions of the security feature may include other print layer thicknesses, other hues, other inks, and / or other types of magnetic materials or amounts.

The security feature may, as mentioned, be designed as a spatially continuous, continuous inking, that is, as a single printing element. The first and second subregions then form subregions of the individual printing element. The security feature may also consist of several spatially separated printing elements. In this case, for example, the first and second partial areas completely comprise partial areas of the different pressure elements or preferably one or more different pressure elements.

The various subregions of the security feature can be made with a single pressure step. With the aid of a suitable post-processing step, preferably in the form of a laser action, the magnetic properties of the printed ink can be selectively changed in certain regions. Thus, a volume can be created with an individualized security feature.

Fig.1

eine Banknote mit einem gedruckten Sicherheitsmerkmal in Form einer individualisierten Matrix;

Fig. 2

eine Banknote mit einem gedruckten Sicherheitsmerkmal, umfassend ein alphanumerisches Zeichen;

Fig. 2A-C

ein gedrucktes Sicherheitsmerkmal, umfassend eine Nummerierung, die mit von Fig. 2A bis Fig. 2C zunehmender Laserleistung gelasert wurde;

Fig. 3A, 3B

ein gedrucktes Sicherheitsmerkmal in Form einer Matrix;

Fig. 4A, 4B

das Verschleiern einer zuvor ausgeprägten Kante;

Fig. 5

das Ausprägen einer zuvor verschleierten Kante;

Fig. 6A, 6B, 6C

verschiedene Rastermuster zum Reduzieren der Magnetpigmentmenge

Fig. 7

ein magnetisches Detektionssignal; und

Fig. 8

eine perspektivische Ansicht eines Tiefdruckelements.

Further embodiments and advantages of the invention are explained below by way of example with reference to the figures. Show it:

Fig.1

a banknote with a printed security feature in the form of an individualized matrix;

Fig. 2

a banknote having a printed security feature comprising an alphanumeric character;

Fig. 2A-C

a printed security feature comprising a numbering number specified by Fig. 2A to Fig. 2C laser power was lasered;

Fig. 3A, 3B

a printed security feature in the form of a matrix;

Fig. 4A, 4B

the obscuring of a previously pronounced edge;

Fig. 5

the stamping of a previously veiled edge;

Figs. 6A, 6B, 6C

different raster patterns for reducing the amount of magnetic pigment

Fig. 7

a magnetic detection signal; and

Fig. 8

a perspective view of a gravure printing element.

The invention will now be explained in more detail using the example of a banknote. To show the Figures 1 and 2 schematically a banknote 1 with two security features: a security strip 2 and a printed security feature. 3

• Magnetpigment BASF 345 (Harteisen)   35,0 %;
• Bindemittel Stichdruck 67 0109/16 (GSI)   37,0 %;
• Kreide (nicht gecoated)   10,0 %;
• Anti-Ablegepaste 67 0113 (GSI)   6,0 %;
• Anti-Ablegepaste 67 0114 (GSI)   6,0 %;
• Mineralöl 190 - 240°C SB   2,0 %;
• Mikronisiertes PE-Wachs   2,0 %; und
• Trockenstoff 67 0141 (GSI)   2,0 %.

In a preferred embodiment of the manufacturing method, the security feature 3 is printed by stitch printing on the disk. The ink to be printed is composed of a known intaglio printing ink as a base color and of a magnetic paste or another type of magnetic printing ink which forms a proportion of 10 to 60% of the printing ink to be printed on. In the preferred embodiment, the magnetic base ink consists of the following components:

• Magnetic pigment BASF 345 (hard iron) 35.0%;
• Binder Stichdruck 67 0109/16 (GSI) 37.0%;
• Chalk (not coated) 10.0%;
• Anti-Slip Paste 67 0113 (GSI) 6.0%;
• Anti-Slip Paste 67 0114 (GSI) 6.0%;
• Mineral oil 190-240 ° C SB 2.0%;
• Micronized PE wax 2.0%; and
• Dry matter 67 0141 (GSI) 2.0%.

In the printed ink, the proportion of the magnetic pigment, that is, the amount of the magnetic substance, is thus between 5% and 20%. The quantities are based on the weight (weight percent).

The magnetic pigment, the binder and the chalk constitute the abrasive portion of the magnetic paste. The remaining components form the so-called mixing proportion of the magnetic paste. The scrubbing portion is dispersed by means of a three-roll chair or a bead mill.

The coercivity of the magnetic pigment should be between 18 and 40 kA / m. Preferably, the isometric magnetic pigment BASF 345, which has a coercive force of 21 kA / m (= 265 Oe).

As the base ink for the printing ink, a yellow gravure ink is used in the preferred embodiment. However, it can also be used intaglio with any other hue, as long as the intaglio ink is suitable for mixing with magnetic paste. In general, the intaglio and the magnetic magnetic paste have different hues, so that not only the magnetic properties of the imprinted ink but also the hue thereof can be influenced by their mixing ratio. In the preferred embodiment, the intaglio ink is yellow and the magnetic paste is olive, so that as the proportion of magnetic paste increases, the resulting ink becomes increasingly dark. Furthermore, the magnetic paste may be changed in accordance with the requirements of the magnetic properties, and a plurality of different magnetic pastes may be mixed with a gravure ink to a printing ink.

It is also possible to use magnetic pastes which are not olive-colored, dark-colored or black, but which are as light as possible or white. This has the advantage that they do not or only slightly change the hue of a bright spot ink. Particularly preferably, the magnetic pastes are transparent to electromagnetic radiation in the infrared wavelength range.

Subsequently, the security element with the selected magnetic properties, in particular with the selected amount of the magnetic pigment, printed on the disk. The remanence flux density obtainable by the imprint can be below the magnitude of the natural geomagnetic field (about 50 μT) and be, for example, 10 μT. The necessary flux density of the print job is determined by the test method, in particular the sensitivity of the magnetic sensors used therein.

For example, a gravure coating of about 8 g / m ² can be produced.

Subsequently, the printed ink is processed with a laser. In the preferred embodiment, an Nd: YAG or Nd: YVO ₄ short-time laser is used with a continuous wave power in the range of 1 to 10 watts, for example 6 watts, a pulse frequency of up to 100 kHz and a power per unit area of 1 up to 5 J / cm ² . The pulse length of the laser pulses is less than 50 ns, preferably less than 20 ns, or even less than 1 ns.

The laser types mentioned have a wavelength of approximately 1064 nm, which is not absorbed by the yellow intaglio ink of the printing ink. When using other intaglio printing inks, another laser wavelength may need to be selected so that it is within a range where the intaglio printing ink does not or only slightly absorb. As a result, the laser interacts over the entire layer thickness of the ink applied, which can be detected at high laser power by traces of smoke on the top and bottom of the printed ink.

The laser parameters, such as power, pulse length, pulse frequency, interaction duration and spot size of the laser, ie its focus, are matched to the various components of the printed ink as well as to the desired result.

Fig. 3A shows a printed security feature consisting of a matrix of 7 x 3 similarly printed printing elements. These may be printed elements printed over the entire surface or printed as a raster, for example a line screen printed in line gravure printing. In the matrix, the left column as well as the upper and lower rows of the printing elements were excluded from the laser treatment, that is, the printing elements which are outside the area A. The printing elements lying in region A were processed with a laser after printing, in which line-by-line printing elements were processed identically. All printing elements within area A have been processed with the same laser power, but the interaction time with the laser within one column increases progressively from top to bottom. To the right of the column, the color difference resulting from the laser treatment is given to an unprocessed printing element. How out Fig. 3A As can be seen, the color difference increases with increasing interaction duration, that is, with the number of laser pulses which have acted on the printing element. In other words, with the amount of the removed magnetic substance, not only the difference in magnetizability and / or remanence flux density over an untreated printing element but also the color difference increases. Similar results are obtained when working with different laser power and the same number of laser pulses.

Typically, the amount of magnetic pigment in the print job is reduced to 10 to 50% of the original value by the laser treatment, such that the remanence flux density decreases, for example, from 10 μT to between 1 and 5 μT, for example, 2.3 or 4 μT.

In Fig. 3B Another security feature is shown, which has the same spatial matrix structure as in Fig. 3A has shown security feature. However, the applied ink differs in the mixing ratio of the intaglio printing ink used and the magnetic paste. The proportion of the olive magnetic paste was reduced here compared to the yellow intaglio ink, resulting in a lighter color tone of the initially printed ink compared to the inks Fig. 3A shown embodiment results. In the in Fig. 3B In addition, a laser factor increased by a factor of 4 was used, it being possible to remove different proportions of the magnetic particles in the print job by means of different laser powers Fig. 3B In the embodiment shown, a detectable difference between the magnetic signal of a processed and an unprocessed printing element already at a smaller color difference than in Fig. 3A shown embodiment generated.

With the in the FIGS. 3A and 3B As shown in FIG. 2, codings and / or individualizations can be introduced into security features consisting of multiple printing elements, as shown in FIG Fig. 1 outlined. Alternatively, other markings, such as alphanumeric characters and / or graphic symbols, may also be introduced into a continuous printing area, as shown in FIG Fig. 2 outlined. In the Fig. 1 and 2 the reference character B designates in each case the partial regions processed by the laser.

The introduced individualization can refer, for example, to a given pattern, can serve for numbering coding or denote a denomination, for example a banknote.

The FIGS. 2A to 2C show a particularly preferred embodiment, in which the security feature 3 consists of a chromatic color, in which a certain amount of a magnetic pigment has been mixed. In this security feature 3, a reference number B is introduced in the form of a numbering with a laser. The reference symbol B is in this case designed as negative writing, ie the laser acts on a large area over a region of the security feature 3, wherein the numbering is generated by reducing or switching off the laser power. FIGS. 2A to 2C show here in each upper part of the security feature 3 with incorporated reference numeral B and in each lower part the reference numeral B, which is introduced only in the substrate of the banknote 1.

• in Fig. 2A die Laserleistung derart gering gewählt, dass der Laser das Substrat der Banknote 1 nicht oder kaum erkennbar verändert bzw. schwärzt (Fig. 2A unten). Trifft der Laser mit der gleichen Laserleistung auf das Sicherheitsmerkmal 3, werden jedoch die magnetischen Pigmente verändert bzw. aufgehellt, so dass der mit dem Laser beaufschlagte Bereich des Sicherheitsmerkmals 3 hell im Vergleich zu den nicht durch den Laser beaufschlagten Bereichen erscheint (Fig. 2A oben). Die Nummerierung erscheint im Farbton der nicht durch den Laser beaufschlagten Bereiche und ist somit als dunkle Schrift gegenüber den mit dem Laser beaufschlagten hellen Bereichen zu erkennen, d.h. die Nummerierung wirkt als Positivschrift.
• in Fig. 2B die Laserleistung derart gewählt, dass der Laser das Substrat der Banknote 1 erkennbar verändert bzw. schwärzt (Fig. 2B unten). Trifft der Laser mit der gleichen Laserleistung auf das Sicherheitsmerkmal 3, werden die magnetischen Pigmente zwar ebenso wie in Fig. 2A verändert bzw. aufgehellt, die Laserleistung ist jedoch so angepasst, dass durch die gleichzeitige Veränderung bzw. Schwärzung des Substrats der mit dem Laser beaufschlagte Bereich des Sicherheitsmerkmals 3 ebenso hell erscheint wie die nicht durch den Laser beaufschlagten Bereiche (Fig. 2B oben). Dies bedeutet, dass sich die Änderung der magnetischen Pigmente und die durch die Farbe hindurchscheinende Änderung des Substrats für einen Betrachter gegenseitig aufheben. Der mit dem Laser beaufschlagte Bereich ist somit ebenso wie die Nummerierung im Sicherheitsmerkmal 3 nicht zu erkennen.
• in Fig. 2C die Laserleistung so hoch gewählt, dass der Laser das Substrat der Banknote 1 stark verändert bzw. schwärzt (Fig. 2B unten). Trifft der Laser mit der gleichen Laserleistung auf das Sicherheitsmerkmal 3, werden zwar ebenso wie in Fig. 2A oder Fig. 2B die magnetischen Pigmente verändert bzw. aufgehellt, durch die gleichzeitige starke Veränderung bzw. Schwärzung des Substrats erscheint jedoch der mit dem Laser beaufschlagte Bereich des Sicherheitsmerkmals 3 dunkler bzw. schwarz im Vergleich zu den nicht durch den Laser beaufschlagten Bereichen (Fig. 2C oben). Dies bedeutet, dass die durch die Farbe hindurchscheinende Änderung bzw. Schwärzung des Substrats die Änderung der magnetischen Pigmente überwiegt. Die Nummerierung erscheint im Farbton der nicht durch den Laser beaufschlagten Bereiche und ist somit als helle Schrift gegenüber den mit dem Laser beaufschlagten dunklen Bereichen zu erkennen, d.h. sie wirkt als Negativschrift.

In the selected embodiment, the applied laser power of Fig. 2A to Fig. 2C towards. Here is:

• in Fig. 2A the laser power is chosen so small that the laser does not change or blacken the substrate of the banknote 1 barely recognizable ( Fig. 2A below). If the laser hits the security feature 3 with the same laser power, however, the magnetic pigments are changed or lightened so that the area of the security feature 3 applied to the laser appears bright compared to the areas not acted on by the laser ( Fig. 2A above). The numbering appears in the color of the areas not acted upon by the laser and can thus be recognized as a dark font with respect to the bright areas exposed to the laser, ie the numbering acts as positive writing.
• in Fig. 2B the laser power is selected such that the laser recognizably changes or blackens the substrate of the banknote 1 ( Fig. 2B below). If the laser hits the security feature 3 with the same laser power, the magnetic pigments, just as in Fig. 2A changed However, the laser power is adjusted in such a way that due to the simultaneous change or blackening of the substrate, the area of the security feature 3 acted upon by the laser appears to be just as bright as the areas not acted on by the laser (FIG. Fig. 2B above). This means that the change in the magnetic pigments and the color change in the substrate will cancel each other out for a viewer. The area acted upon by the laser is therefore not identifiable as well as the numbering in the security feature 3.
• in Fig. 2C the laser power is chosen so high that the laser greatly alters or blackens the substrate of the banknote 1 ( Fig. 2B below). If the laser hits the security feature 3 with the same laser power, then as well as in Fig. 2A or Fig. 2B the magnetic pigment changes or lightens, however, due to the simultaneous strong change or blackening of the substrate, the region of the security feature 3 applied with the laser appears darker or black compared to the areas not acted on by the laser ( Fig. 2C above). This means that the change or blackening of the substrate that transpires through the color outweighs the change of the magnetic pigments. The numbering appears in the color of the not acted upon by the laser areas and is thus recognizable as a light font compared to the acted upon by the laser dark areas, ie it acts as negative writing.

In a further preferred embodiment, both the printed ink and its laser-processed sections integrate into the rest of the design of the data carrier, for example in a background printing or in a subsequent overprinting, whereby the security feature and in particular its portions machined with the laser are laminated.

In the FIGS. 4A and 4B Two variants show the obscuring of a transition between two areas of a security element. For this purpose, a spatially slow change in the amount of magnetic pigment between a region C with applied ink with magnetic pigments and a portion B is produced with a reduced amount of magnetic pigments. In the upper part of the two figures, a plan view of the security feature is shown in each case, in which the portion B is formed rectangular in the surrounding area C. In the lower part of the two figures, the intensity of the laser radiation used to reduce the amount of magnetic pigments is sketched. The respective left edge of the subregions B is a so-called resolved edge or a veiled transition, which should produce no or only a small signal in the detection with the magnetic sensor, wherein the detection direction is parallel to the x direction here. For this purpose, the full intensity of the laser radiation, which is necessary for reducing the magnetic pigments to the desired amount, only at a certain distance from the left edge of the portion B is set. In between, the intensity of the laser radiation increases with increasing distance from the edge of the subarea B ( Fig. 4A ) or gradual ( Fig. 4B ), resulting in the desired spatially slow change in the amount of magnetic pigment in the x-axis direction.

With the same technique of changing the intensity of the laser radiation with increasing distance from an edge can also be an initially sharp edge or a spatially rapid transition, as it arises, for example, in a directly adjacent printing of two inks with different amounts of magnetic pigment in a blurred, fogged edge With be converted to a wide transition region which produces no or only a small detection signal.

In Fig. 5 the opposite case is shown. Here an area C is printed with ink with a curved edge. As a result, the printing produces a blurred, fogged edge, that is to say the magnetic pigments contained in the printing ink produce only a small detection signal, since the average amount of magnetic pigment increases only slowly, depending on the position on the x-axis within the region of the curved edge. This blurred, fogged edge can be converted to a sharp, distinct edge with a strong detection signal by using laser radiation in the area of the curved edge to adjust the amount of magnetic pigments in region C to the amount of magnetic pigments in the surrounding region. In the simplest case, no magnetic pigments are present in the surrounding area and in the region of the curved edge of area C, the magnetic pigments are completely removed to produce the sharp edge.

In the Figures 6A, 6B and 6C schematically different types of rasters are shown, as they can be used to produce a portion B with reduced amount of magnetic pigment. The illustrated grid points and grid lines represent the interaction region of the laser radiation. The interaction region is ideally very narrow. The raster pattern, the grid spacings and the raster strengths are selected according to the requirements and can vary over the subarea B.

In the upper part of Fig. 7 schematically a plan view of a security element is shown. This has a region C with an applied printing ink with magnetic pigments and a portion B with the same ink, but with a reduced amount of magnetic pigment on, the amount of magnetic pigment was reduced using a line grid. In the lower area, the detection signal U of a magnetic sensor is shown, wherein the detection direction is in the x direction. The grid spacings of the line grid in subarea B are below the spatial resolution of the magnetic sensor, which is despite the screening and thus not full-scale reduction of the amount of magnetic pigment in area B, at the boundary line D between area C and section B is a sharp edge, which is a strong detection signal of the magnetic sensor generated. Another sharp edge is located on the right boundary line E of region C. This embodiment is suitable for the case of a small amount of ink per area and is particularly suitable for bright printing inks.
In Fig. 8 a gravure printing element is shown in perspective view, which consists of a printing ink with magnetic pigments. In this case, only in a near-surface portion B, the amount of magnetic pigment is reduced. In the remaining area C of the gravure element, the amount of magnetic pigment is not reduced. A possible color change of the printing ink of the gravure printing element can only take place in the small subregion B, which greatly reduces its visual perceptibility.

In addition to the gravure printing element 3, the laser can also be used to produce other security features such as those in the Figures 1 and 2 schematically represented security thread 2, other film elements and other suitable for laser processing security features are processed.

Claims (19)

1. A method for the manufacturing of a data carrier (1) having a printed security feature (3), comprising the step of

   (1) printing printing ink onto the data carrier (1) for the production of at least a part of the security feature (3), wherein the printing ink contains a quantity of a magnetic substance, by the printing ink mixed with a base ink comprising a magnetic paste with para- and/or ferro-magnetic particles,

   characterized by the further step of

   (2) reducing the quantity of the magnetic substance in at least a partial area (A, B) of the printed printing ink, by at least a part of the magnetic particles being removed or erased.
2. The method according to claim 1, characterized in that the reduction of the quantity of the magnetic substance is effected by interaction with the radiation of an electromagnetic radiation source, in particular of a laser, preferably with pulse lengths of less than 50 ns.
3. The method according to any of the preceding claims, characterized in that by the reduction of the quantity of the magnetic substance the shade of the printing ink of the partial area (A, B) changes by a color difference of less than 25, preferably less than 15, 5, 2 or 1.
4. The method according to any of the preceding claims, characterized in that the partial area (A, B) is concealed by an underprint and/or overprint.
5. The method according to any of the preceding claims, characterized in that the printing of the printing ink onto the data carrier (1) produces a tactilely perceptible element, the application is preferably effected by a gravure printing and further preferably in the partial area an application of ink of 8 g/m² is applied.
6. The method according to any of the preceding claims, characterized by the further step of

   - printing further printing ink onto the data carrier (1) for the production of a further part of the security feature, wherein the further part of the security feature differs from the part applied in step (1) in the quantity of the magnetic substance which the further printing ink contains upon printing, in the shade of the printing ink, and/or in the thickness of the applied print.
7. The method according to claim 6, characterized by the further step of

   - reducing the quantity of the magnetic substance in at least a partial area (A, B) of the further printed printing ink.
8. The method according to any of the preceding claims, characterized in that the contour of the area of the printing ink and/or of the partial area (A, B) has a rectilinear edge lying transverse to a direction of detection, a curved edge lying transverse to the direction of detection and/or an edge lying transverse to the direction of detection and having a wide transition region.
9. The method according to any of the preceding claims, characterized in that the quantity of the magnetic substance in the at least one partial area (A, B) is reduced in a grid-like manner.
10. The method according to any of the preceding claims, characterized in that the quantity of the magnetic substance is reduced in the at least one partial area (A, B) only at the surface of the printing ink.
11. The method according to any of claims 2 to 10, characterized by the further step of

    - introducing a coding into a further security feature (2) of the data carrier (1), preferably into a foil element and/or a security thread, through interaction with the electromagnetic radiation.
12. A data carrier (1) having a printed security feature (3), wherein the security feature (3) has a first (C) and a second partial area (A, B) with the same print layer thickness and the same printed printing ink, said printing ink mixed with a base ink comprising a magnetic substance in the form of a magnetic paste with para- and/or ferro-magnetic particles, and the first partial area (C) contains a first quantity of the magnetic substance, characterized in that the second partial area (A, B) has a second quantity of the magnetic substance that is reduced compared to the first partial area (C), at least a part of the magnetic particles being removed or erased.
13. The data carrier (1) according to claim 12, characterized in that the color difference between the shade of the first partial area (C) and the shade of the second partial area (A, B) amounts to less than 25, preferably less than 15, 5, 2 or 1.
14. The data carrier (1) according to any of claims 12 to 13, characterized in that the first (C) and/or second partial area (A, B) is concealed by an underprint and/or overprint.
15. The data carrier (1) according to any of claims 12 to 14, characterized in that the security feature (3) forms a tactilely perceptible print element, preferably is a gravure print element, and further preferably the application of ink in the first (C) and second partial area (A, B) of the security feature (3) amounts to 8 g/m².
16. The data carrier (1) according to any of claims 12 to 15, characterized in that the printed security feature (3) comprises a further partial area printed with magnetic printing ink, which differs from the first partial area of the security feature in the quantity of the magnetic substance in the printing ink, in the shade of the printing ink, and/or in the thickness of the applied print.
17. The data carrier (1) according to any of claims 12 to 16, characterized in that the contour of at least one of the partial areas of the security feature (3) has a rectilinear edge lying transverse to a direction of detection, a curved edge lying transverse to the direction of detection and/or an edge lying transverse to the direction of detection and having a wide transition region.
18. The data carrier (1) according to any of claims 12 to 17, characterized in that the quantity of the magnetic substance in the second partial area (A, B) is reduced in a grid-like manner.
19. The data carrier (1) according to any of claims 12 to 18, characterized in that the amount of the magnetic substance in the second partial area (A, B) is reduced only at the surface of the printing ink.

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