EP3874475B1 - Magnetic testing of valuable documents - Google Patents

Description

The invention relates to a method and a testing device for the magnetic testing of valuable documents, such as banknotes, checks, cards, tickets, coupons, as well as a valuable document processing device.

It is known from the prior art to equip valuable documents with security elements, such as security strips or security threads, which contain magnetic material. The magnetic material can be applied to the security element either continuously or only in certain areas, for example in the form of a code. For example, a specific sequence of magnetic and non-magnetic areas, which is characteristic of the document of value, is used to magnetically encode a security element. It is also known to use different magnetic materials for magnetic coding, for example with different coercive field strengths. In some magnetic codings, two different coercive magnetic materials are used, from which low-coercive and high-coercive magnetic areas are formed, which are arranged on the security element.

It is also known to mechanically check banknotes with security threads that have a magnetic coding made of different coercive materials. In order to be magnetized, the banknotes are transported through one or more magnetic field areas, whereby they first pass through a strong magnetic field that magnetizes both the high and low coercive magnetic areas. The banknotes then pass through a weaker magnetic field that only changes the direction of magnetization of the low-coercivity magnetic areas, while the high-coercivity magnetic areas remain magnetized in the same way. The resulting magnetization is checked by one or more magnetic detectors arranged according to the magnetic field areas. Magnetoresistive detectors, AMR elements, GMR elements, TMR elements or Hall elements, which require little space, are usually used as magnetic detectors. These are arranged in large numbers or density transversely to the transport direction of the document of value in order to enable a high spatial resolution, so that even finely structured magnetic codes (with short magnetic areas) can be read. However, such magnetic detectors are very complex to manufacture. Such a test method with a corresponding device is, for example, from DE 10 2009 039588 A1 known.

In addition, inductive magnetic detectors are known, which usually only have a few measurement tracks transverse to the transport direction of the document of value and offer a spatial resolution that is too low to read finely structured magnetic codes. Inductive magnetic detectors are therefore often only used to detect the presence of a magnetic security element. It is also known to replace an inductive magnetic detector with two or more of the other detector elements mentioned above, for example with GMR elements, and to electronically interconnect these detector elements in such a way that their magnetic signal is similar to that of an inductive magnetic detector. Advantageously, their magnetic signal can then be subjected to the same evaluation that can also be used for the magnetic signal of the inductive magnetic detector.

The invention is therefore based on the object of proposing an evaluation for the magnetic signal of a magnetic detector, in particular an inductive magnetic detector, generated by a security element, through which the magnetic coding of a security element can be checked.

This task is solved by the subject matter of the independent claims. Advantageous developments and refinements of the invention are specified in claims dependent thereon.

The valuable document to be checked has a security element with one or more magnetic areas. The magnetic areas include, for example, one or more low-coercive magnetic areas made of a low-coercive magnetic material with a first coercive field strength and one or more high-coercive magnetic areas made of a high-coercive magnetic material with a second coercive field strength that is greater than the first coercive field strength, and optionally one or more combined magnetic areas, which have both the high coercivity and the low coercivity magnetic material. Depending on the type of security element, it can have both high and low coercive magnetic areas, but it can also only have one type of these magnetic areas.

To check the document of value, the document of value or the security element of the document of value is magnetized by a first magnetic field region whose magnetic field strength is greater than the first and than the second coercive field strength. The magnetization of the high-coercivity magnetic material (a high-coercivity and possibly a combined magnetic region) and the magnetization of the low-coercivity magnetic material (a low-coercivity and possibly a combined magnetic region) are aligned uniformly in a first magnetization direction. The document of value or the security element is then magnetized by a second magnetic field region, the magnetic field strength of which is greater than the first coercive field strength, but smaller than the second coercive field strength. The second magnetic field region is oriented such that the magnetization of the low-coercivity magnetic material (a low-coercivity and possibly a combined magnetic area) is aligned in a second magnetization direction that is different from the first magnetization direction. The magnetization of the high-coercivity magnetic material (a high-coercivity and possibly a combined magnetic region) remains aligned in the first magnetization direction during the second magnetization.

The first and second magnetization of the security element by the first and second magnetic field region results in the magnetization of one or more low-coercivity magnetic regions possibly present on the security element being aligned in a different magnetization direction than the magnetization of one or more high-coercivity magnetic regions possibly present on the security element . The first and second magnetic field regions may be spatially different regions of the same magnetic field generated by the same magnet(s). But they can also be generated by the magnetic fields of several magnets. The first and second magnetic field areas can be provided by the testing device itself or by a value document processing device in which the testing device is contained. However, the first and second magnetization can also be carried out outside of such devices, for example by a magnetization device, into the magnetic field areas of which the valuable documents are introduced manually or mechanically for magnetization.

For a fully automatic test, the first and second magnetic field areas as well as a (in particular inductive) magnetic detector are provided along a transport path of the document of value, along which the document of value is transported. The document of value with the security element first passes through the first magnetic field area first magnetic field strength pointing in the first magnetic field direction, which is greater than the coercive field strength of the two magnetic materials, and then the second magnetic field region of a second magnetic field strength pointing in a different, second magnetic field direction, which is greater than the coercive field strength of the low-coercivity magnetic material, but is smaller than the coercive field strength of the high-coercivity magnetic material. Accordingly, when the document of value is transported along the transport path, both magnetic materials are first magnetized in the first magnetic field area and then only the low-coercivity magnetic material is re-magnetized in the second magnetic field area, whereas the magnetization of the high-coercivity magnetic material generated by the first magnetic field area remains. The two magnetic materials are then magnetized in different magnetization directions.

After the first and second magnetization, the valuable document with the security element is transported along a transport direction past an inductive magnetic detector, which has several measuring tracks transverse to the transport direction of the valuable document. In the measurement tracks, the magnetic detector (at least in the area of the security element) detects a magnetic signal as a function of time, ie as a function of the position along the transport direction of the document of value transported past the magnetic detector. Instead of an inductive magnetic detector, magnetoresistive elements, AMR, GMR, TMR or Hall elements can also be used, which are electronically connected to one another in a differential manner or whose magnetic signals are subtracted from one another in such a way that the resulting magnetic signal is similar to that of an inductive magnetic detector.

The magnetic signals of the security element detected by the individual measurement tracks are evaluated. The strongest two local minima of the respective magnetic signal are determined for several or all measurement tracks, which the respective magnetic signal of the respective measurement track has as a function of time or as a function of the position along the transport direction in the area of the security element. Alternatively or additionally, the strongest two local maxima of the respective magnetic signal can also be determined, which the respective magnetic signal of the respective measurement track has as a function of time or as a function of the position along the transport direction in the area of the security element. In the case of minima evaluation, a Miruma comparison value of the respective measurement track is determined for several of the measurement tracks by comparing the amplitude of the magnetic signal in the second strongest local minimum with the amplitude of the magnetic signal in the strongest local minimum. In the case of maxima evaluation, a maxima comparison value of the respective measurement track is determined for several of the measurement tracks by comparing the amplitude of the magnetic signal in the second strongest local maximum with the amplitude of the magnetic signal in the strongest local maximum. The magnetic coding of the security element is checked based on the minimum comparison values of several or all measurement tracks and/or based on the maximum comparison values of several or all measurement tracks. An evaluation of not all, but only several (preferably adjacent) measurement tracks can be sufficient if the magnetic coding is repeated along the security element. Furthermore, those measurement tracks that detect the edge of the security element can be ignored when checking the magnetic coding.

A local minimum/maximum of the respective magnetic signal is the point of the magnetic signal at which the amplitude of the magnetic signal is as As a function of time or as a function of position along the transport direction, a local minimum/local maximum occupies. The (second) strongest local minimum is the local minimum of the respective magnetic signal at which the amplitude of the magnetic signal of all local minima has the (second) largest distance from the zero point or from the negative offset of the magnetic signal. The (second) strongest local maximum is the local maximum of the respective magnetic signal at which the amplitude of the magnetic signal of all local maxima has the (second) largest distance from the zero point/offset of the magnetic signal to the positive.

Based on the minimum comparison values and/or based on the maximum comparison values of the respective measurement track, it can be checked whether the security element in the respective section of the security element (viewed transversely to the transport direction of the document of value), whose magnetic signal has detected the respective measurement track, has a low coercivity or a has a high-coercivity magnetic area or possibly a combined magnetic area. Each magnetic area can be identified either as a combined magnetic area or as a high-coercivity or low-coercivity magnetic area. The magnetic coding can also be checked using the minimum comparison values and/or the maximum comparison values to determine whether the magnetic coding has magnetic areas of different coercive field strengths (different magnetic materials) or only magnetic areas of the same coercive field strength (made of the same magnetic material).

When comparing the two strongest minima or the two strongest maxima, for example, their difference (the difference) or their ratio is calculated. The minimum comparison value is, for example, the minimum difference u=m2-m1 or u=m1-m2 between the amplitude m2 of the magnetic signal im second strongest local minimum and the amplitude m1 of the magnetic signal in the strongest local minimum. Analogously, the maximum comparison value is, for example, the maximum difference U=M2-M1 or U=M1-M2 between the amplitude M2 of the magnetic signal in the second strongest local maximum and the amplitude M1 of the magnetic signal in the strongest local maximum.

Alternatively, the minimum comparison value can be the minimum ratio v=m2/m1 or v=m1/m2 between the amplitude m2 of the magnetic signal in the second strongest local minimum and the amplitude m1 of the magnetic signal in the strongest local minimum, and the maximum comparison value can be the maximum -Ratio V=M2/M1 or V=M1/M2 between the amplitude M2 of the magnetic signal in the second strongest local maximum and the amplitude M1 of the magnetic signal in the strongest local maximum.

The absolute amount of the strongest local minimum (global minimum) of the respective magnetic signal or the absolute amount of the strongest local maximum (global maximum) of the respective magnetic signal, which represents the respective magnetic signal of the respective measurement track as a function of time or as a function of the position along the transport direction in the area of the security element can be compared with an insignificance threshold. If the insignificance threshold is exceeded, it can be concluded that the security element in the respective section (transverse to the transport direction), whose magnetic signal has detected the respective measurement track, has a (eg high-coercivity or low-coercivity or possibly combined) magnetic area. Preferably, only when the insignificance threshold is exceeded is it evaluated whether the security element in the respective section whose magnetic signal has detected the respective measurement track has a high-coercivity or a low-coercivity (or possibly a combined) magnetic area. If the value falls below This evaluation is not carried out when the insignificance threshold is exceeded, but from falling below it it is concluded that the security element in the respective section, whose magnetic signal has detected the respective measurement track, has no low-coercivity and no high-coercivity magnetic area (and also no combined magnetic area).

For example, for one or more measurement tracks of the magnetic detector, the respective minimum comparison value or the respective maximum comparison value is compared with a first threshold (and possibly also further thresholds). Based on whether the minimum comparison values of the individual measurement tracks exceed or fall below the first threshold or based on whether the maximum comparison values of the individual measurement tracks fall below or exceed the first threshold, information about the magnetic coding of the security element can be obtained. For example, depending on whether the minimum comparison value of the respective measurement track exceeds or falls below the first threshold and/or depending on whether the maximum comparison value of the respective measurement track falls below or exceeds the first threshold, a decision can be made as to whether the security element in the respective section, whose magnetic signal has detected the respective measurement track, has a high-coercivity (or possibly a combined) magnetic area or has a low-coercivity magnetic area.

The shape of the inductive magnetic signal depends on the order in which the two inductive measuring heads of the inductive magnetic detector are differentially connected to one another. If the order of the differential circuit is reversed, the positive and negative amplitude of the magnetic signal are reversed, causing the maximum and minimum to be swapped. Therefore, the evaluation logic must be adapted depending on That is, depending on the order selected for the differential switching, a decision must be made as to whether a magnetic area is identified as a low-coercivity or a high-coercivity magnetic area when the first threshold is exceeded or fallen below.

If, for example, an inductive sensor like in the example Fig. 1 is used, in the case when the minimum comparison value of the respective measurement track exceeds the first threshold and/or when the maximum comparison value of the respective measurement track falls below the first threshold, it is decided that the security element in the respective section whose magnetic signal corresponds to the respective one The measurement track has detected a highly coercive (or possibly a combined) magnetic area. And in the case when the minimum comparison value of the respective measurement track falls below the first threshold and/or when the maximum comparison value of the respective measurement track exceeds the first threshold, it is decided that the security element in the respective section whose magnetic signal detects the respective measurement track has a low coercive magnetic region.

However, if an inductive sensor with a reverse differential circuit is used or the first and second magnetization directions are swapped, in the case when the minimum comparison value of the respective measurement track falls below the first threshold and/or when the maximum comparison value of the respective measurement track exceeds the first threshold exceeds, decided that the security element in the respective section, whose magnetic signal has detected the respective measurement track, has a highly coercive (or possibly a combined) magnetic area. And in the case when the minimum comparison value of the respective measurement track exceeds the first threshold and/or when the maximum comparison value of the respective measurement track falls below the first threshold, it is decided that the security element in the respective section, whose magnetic signal has detected the respective measurement track, has a low-coercivity magnetic area.

When checking the magnetic coding of the security element, a decision can be made based on the minimum comparison values and/or on the basis of the maximum comparison values of several measurement tracks whether the security element is assigned to a first or a second security element category. The first security element category includes, for example, those security elements that also have high-coercivity magnetic material, e.g. have one or more high-coercivity magnetic areas and/or one or more combined magnetic areas. The first security element category is referred to, for example, as a “multicode security element”. The second category of security elements includes those security elements that do not have a high-coercivity magnetic material, e.g. that only have low-coercivity magnetic areas. The second security element category is referred to, for example, as “no multicode security element”.

The security element is, for example, assigned to the first security element category if, with a minimum number n (natural number n) of measurement tracks, the minimum comparison value calculated for the respective measurement track exceeds the first threshold and/or with a minimum number n of measurement tracks, that for the respective measurement track calculated maximum comparison value falls below the first threshold. Otherwise (if neither the respective minimum comparison value exceeds the first threshold for the minimum number of measurement tracks nor does the respective maximum comparison value fall below the first threshold for the minimum number of measurement tracks), the security element is assigned to the second security element category. This is the case, for example, when exceeding or falling below the limit is not observed in any of the measurement tracks or if the number of measurement tracks in which the first threshold is exceeded or undershot is less than the minimum number n.

In the case of an inductive sensor with reverse differential switching, the security element is assigned to the first category of security elements if, with a minimum number n of measurement tracks, the minimum comparison value calculated for the respective measurement track falls below the first threshold and/or with a minimum number n of measurement tracks, the minimum comparison value for the The maximum comparison value calculated for each measurement track exceeds the first threshold. Otherwise, the security element is assigned to a second category of security elements.

The category assignment of the security element is possible by comparing it with the first threshold. As an alternative to comparing with a threshold, the category assignment could also be based on the spread or standard deviation of the results of the minima comparison along the security element. If the standard deviation is large, the security element would be assigned to a first security element category ("security element with different coercive magnetic areas") and if the standard deviation is small, the security element would be assigned to a second security element category ("security element with only one type of magnetic area").

Optionally, for one or more measurement tracks of the magnetic detector, the respective minimum comparison value and/or the respective maximum comparison value can additionally be compared with a second threshold. In the case when the minimum comparison value of the respective measurement track and/or the maximum comparison value of the respective measurement track is between lies between the first and second thresholds, it can be concluded that the security element has a combined magnetic area in the respective section whose magnetic signal has detected the respective measurement track. If the magnetic coding of the security element is checked based on the minimum comparison values of several of the measurement tracks, a second threshold is used that is above the first threshold. And if the magnetic coding of the security element is checked based on the maximum comparison values of several of the measurement tracks, a second threshold is selected that is below the first threshold.

The high-coercivity and the low-coercivity magnetic materials of the combined magnetic area are, for example, arranged on top of each other. Alternatively, the combined magnetic region has the high-coercivity and the low-coercivity magnetic material in the form of a mixture. The combined magnetic region may have the same or different amounts of the high-coercivity and low-coercivity magnetic materials. It can be designed such that the high-coercivity magnetic material of the combined magnetic region and the low-coercivity magnetic material of the combined magnetic region have essentially the same remanent flux density, wherein the combined magnetic region can in particular contain equal amounts of the high-coercivity and the low-coercivity magnetic material.

The invention also relates to a testing device which is set up to test the above-mentioned document of value, which is transported along a transport direction past a magnetic detector, in particular an inductive magnetic detector, of the testing device. The testing device has the (in particular inductive) magnetic detector, which has a plurality of measuring tracks transverse to the transport direction of the document of value and is set up in each of the measuring tracks (at least in the area of the security element). to detect a magnetic signal as a function of time or as a function of position along the transport direction of the document of value. For each measurement track, the magnetic detector has an inductive measuring head with two measuring coils, which are arranged one after the other in the transport direction of the document of value. The two measuring coils are preferably connected in a difference to one another and the difference signal of the two measuring coils is used as the magnetic signal of the respective measuring track. Alternatively, instead of one measuring coil, two magnetoresistive elements, AMR, GMR, TMR or Hall elements can be used, which are connected to each other in a differential manner or whose magnetic signals are subtracted from one another in such a way that the shape of the resulting magnetic signal corresponds to the shape of the magnetic signal resembles a single measuring coil of an inductive magnetic detector.

Before the magnetic signals were detected by the magnetic detector, the security element was magnetized by the above-mentioned first magnetic field region, the magnetic field strength of which is greater than the first and second coercive field strength, and then magnetized by the above-mentioned second magnetic field region, the magnetic field strength of which is greater than the first coercive field strength but is smaller than the second coercive field strength, wherein the security element was magnetized by the second magnetic field region in a different direction than by the first magnetic field region. The testing device also has an evaluation device (connectable or connected to the magnetic detector) which is set up to evaluate the magnetic signals of the security element detected in the individual measurement tracks. The testing device can be intended to be installed in a device for processing valuable documents. The value document processing device has a transport device for Documents of value, which are designed to transport documents of value one after the other along the transport direction past the (in particular inductive) magnetic detector of the testing device.

For the first and second magnetization of the security element, the testing device or the valuable document processing device can have one or more magnets which, along the transport path of the valuable document, provide the above-mentioned first magnetic field region for first magnetizing the security element and (along the transport path behind the first magnetic field region) the above-mentioned second magnetic field region second magnetization of the security element. Viewed along a transport path of the valuable document through the checking device or through the valuable document processing device, the first magnetic field region is arranged in front of the second magnetic field region and the magnetic detector is arranged after the second magnetic field region. The magnetic field direction of the second magnetic field region is different than that of the first magnetic field region, for example essentially anti-parallel thereto. The magnetic field strength of the first magnetic field region is greater than the second coercive field strength. The first magnetic field region is designed to align the magnetization of the low-coercivity magnetic material and the magnetization of the high-coercivity magnetic material in a first magnetization direction for a security element transported through the first magnetic field region. The second magnetic field region is designed to align the magnetization of the low-coercivity magnetic material in a second magnetization direction that is different from the first magnetization direction, for example essentially antiparallel to the first magnetization direction, in the security element transported through the second magnetic field region, but with the magnetization of the high-coercivity magnetic material in the first Direction of magnetization remains aligned.

The evaluation device has evaluation software which is set up to determine the strongest two local minima of the respective magnetic signal and/or the strongest two local maxima of the respective magnetic signal for several or all of the measurement tracks, which determine the respective magnetic signal of the respective measurement track as a function the time or as a function of the position along the transport direction of the document of value in the area of the security element. Furthermore, the software of the evaluation device is set up to determine a minimum comparison value of the respective measurement track by comparing the amplitude of the magnetic signal in the second strongest local minimum with the amplitude of the magnetic signal in the strongest local minimum and / or to determine a maximum comparison value of the respective measurement track Comparing the amplitude of the magnetic signal in the second strongest local maximum with the amplitude of the magnetic signal in the strongest local maximum. And the software of the evaluation device is set up to check a magnetic coding of the security element based on the minimum comparison values of several of the measurement tracks and / or based on the maximum comparison values of several of the measurement tracks.

For example, the software of the evaluation device is set up to decide, when checking the magnetic coding of the security element, based on the minimum comparison values and/or based on the maximum comparison values of the individual measurement tracks, whether the security element is assigned to a first or a second security element category, and/ or to check whether the security element in the respective section (transverse to the transport direction of the valuable document), whose magnetic signal has detected the respective measurement track, has a low-coercivity or a high-coercivity magnetic area (or, if necessary, a combined magnetic area).

Fig. 1

eine Wertdokumentbearbeitungsvorrichtung mit einer Magnetisierungseinrichtung, einem Magnetdetektor und einer Auswerteeinrichtung,

Fig. 2

den Verlauf der Magnetfeldlinien für die Magnetisierungseinrichtung aus Fig. 1,

Fig. 3a-d

Magnetsignale des induktiven Magnetdetektors: für einen niederkoerzitiven Magnetbereich (Fig. 3a), für einen hochkoerzitiven Magnetbereich (Fig. 3b), für einen kombinierten Magnetbereich (Fig. 3c), für eine in der Nähe der Magnetbereiche des Sicherheitselements liegende Messspur (Fig. 3d),

Fig. 4a-d

ein erstes Beispiel für ein Sicherheitselement (Fig. 4a, 4c) und das für dieses entlang des Sicherheitselements ermittelte Minima-Verhältnis v (Fig. 4b) und Maxima-Verhältnis V (Fig. 4d),

Fig. 5a-d

ein zweites Beispiel für ein Sicherheitselement (Fig. 5a, 5c) und das für dieses entlang des Sicherheitselements ermittelte Minima-Verhältnis v (Fig. 5b) und Maxima-Verhältnis V (Fig. 5d).

The invention is explained below by way of example using the following figures. Show it:

Fig. 1

a value document processing device with a magnetization device, a magnetic detector and an evaluation device,

Fig. 2

the course of the magnetic field lines for the magnetization device Fig. 1 ,

Fig. 3a-d

Magnetic signals of the inductive magnet detector: for a low-coercivity magnetic range ( Fig. 3a ), for a high-coercivity magnetic range ( Fig. 3b ), for a combined magnetic range ( Fig. 3c ), for a measurement track located near the magnetic areas of the security element ( Fig. 3d ),

Fig. 4a-d

a first example of a security element ( Fig. 4a , 4c ) and the minimum ratio v determined for this along the security element ( Fig. 4b ) and maxima ratio V ( Fig. 4d ),

Fig. 5a-d

a second example of a security element ( Fig. 5a , 5c ) and the minimum ratio v determined for this along the security element ( Fig. 5b ) and maxima ratio V ( Fig. 5d ).

Figure 1 shows schematically a section of a valuable document processing device, which is set up to check a magnetizable security element 31 of a valuable document 30. The valuable document processing device contains a testing device 100, which has an inductive magnetic detector 50 and an evaluation device 60, and possibly other elements (not shown), such as input and output devices for valuable documents and operating elements. The value document processing device has a transport device 17 and a magnetization device 10 made of two opposing magnets 11, 12, which is arranged along the transport path of the valuable document in front of the inductive magnetic detector 50 and away from it.

In this example, the security element 31 has a low-coercivity magnetic material with a first, low coercivity and a high-coercivity magnetic material with a second, larger coercivity, which are contained in several sections of the security element transverse to the transport direction (y-direction). Thus, a high-coercivity magnetic region h of the security element 31 only has the high-coercivity magnetic material, but not the low-coercivity magnetic material, and a low-coercivity magnetic region 1 of the security element 31 only has the low-coercivity magnetic material, but not the high-coercivity magnetic material. Alternatively, the security element 31 can also have only one type of these magnetic materials. If necessary, a combined magnetic region k can also be present, which has both of the aforementioned magnetic materials. The existing magnetic areas h or 1 or h, 1 or h, k, 1 form a magnetic coding of the security element 31.

The valuable document 30 with the security element 31 is transported along a transport direction T by means of the transport device 17 of the valuable document processing device. In Figure 1 Two upper and two lower transport belts are shown as examples, between which the document of value 30 is clamped and transported. The transport device 17 can also include transport rollers. Before the security element 31 is tested, it is magnetized by the two magnets 11, 12 in such a way that the magnetization directions of the high and low coercive magnetic areas h, 1 differ from one another. In the example of Fig. 1 the magnetization directions are at least approximately antiparallel to one another. The magnetization device provides this along the transport area a first magnetic field area 15 and a second magnetic field area 16 downstream of the first magnetic field area in the transport direction T, cf. Fig. 2 .

The two previously described magnetic field areas 15, 16 are generated by means of two bar magnets 11, 12, which lie opposite each other with both their north poles N and their south poles S. In the present exemplary embodiment, the magnetic axes 13 and 14 of the two magnets 11, 12 are aligned parallel to one another and to the transport direction T, but they can also be opposite to the transport direction T. By using two magnets arranged in this way to generate the two magnetic field areas 15, 16, antiparallel magnetization of the high and low coercive magnetic areas is achieved with little effort.

The magnetic field lines of the magnetic field generated by such a magnetization device 10 are in Figure 2 shown schematically, these magnetic field lines in one to the x and z axes of Figure 1 shows a parallel plane that intersects the two magnets 11 and 12 in the middle. Accordingly, viewed in the z direction, there is a magnetic field aligned in the transport direction T (first magnetic field region 15) exactly in the middle between the magnets and viewed in the x direction between the poles N, S of the magnets 11, 12. Seen in the transport direction T, downstream of it and behind the two magnets 11, 12 there is a magnetic field (second magnetic field region 16) with a lower magnetic field strength, which is aligned opposite to the transport direction T. In the present example, the magnetic field directions are oriented parallel or anti-parallel to the transport direction of the document of value. However, one or both can also be different, for example perpendicular to the transport direction T of the document of value (parallel or anti-parallel to the in Fig. 1 y-direction or z-direction shown) or oriented obliquely to these directions.

Alternatively, the two magnetic areas 15, 16 can also be generated by a single magnet 11 or 12 or by two or four magnets whose magnetic axes are perpendicular to the transport direction (z direction), e.g. which are arranged above and/or below the document of value and face each other with their magnetic poles of the same name. Instead of the anti-parallel alignment, other angles to one another can also be selected for the two magnetic field directions.

A first magnetization is achieved through the first magnetic field region 15, in which both the magnetization of the low-coercivity magnetic region 1 and that of the high-coercivity magnetic region h are aligned along the transport direction T. In the second magnetic field region 16, only the magnetization of the low-coercivity magnetic region 1 is changed in the opposite direction to the transport direction T. Since the magnetic field strength of the second magnetic field region 16 is lower than the second coercive field strength, the high-coercivity magnetic region h is not remagnetized by the second magnetic field region 16. However, the magnetization of the low-coercivity magnetic region 1 is aligned approximately anti-parallel to the transport direction T by the second magnetization.

In this example, the combined magnetic region k is designed such that the low-coercive magnetic material of the combined magnetic region and the high-coercive magnetic material of the combined magnetic region have at least approximately the same remanent flux density. In this case, if the low-coercivity magnetic material of the combined magnetic region is antiparallel to the high-coercivity through the second magnetic field Magnetic material of the combined magnetic area is magnetized, ideally a vanishing resulting magnetization of the respective combined magnetic area k is achieved.

After the first and second magnetization in the two magnetic field areas 15, 16, magnetic signals of the security element are detected by the inductive magnetic detector 50 and the magnetic signals are evaluated in order to check the magnetic coding of the security element. The inductive magnetic detector 50 has several measuring tracks L (in Fig. 1 four), each of which has an inductive measuring head. Each of the inductive measuring heads has two measuring coils 51 with a soft magnetic core and a magnet 52 in between to generate a magnetic field that is constant over time. During the detection of the magnetic signals, the magnetic field generated by the respective magnet 52 acts on the security element 31. To generate the time-constant magnetic field, a single appropriately sized magnet can also be used for all measurement tracks. When a magnetized security element 31 is transported past, a current is induced in the respective measuring coil 51. The measuring coils 51 generate corresponding signals, which are referred to as magnetic signals. The two measuring coils 51 of the respective measuring head are preferably switched in a difference to one another, so that the difference signal of the two measuring coils 51 is generated as a magnetic signal for each measuring track L. Through this differential circuit, external magnetic influences acting on both measuring coils 51 at the same time can be minimized, since the electrical signals of the measuring coils 51 approximately cancel each other out when connected in opposite directions. For further processing, the magnetic signals M of each measurement track L can be amplified with a separate amplifier. The magnetic signals M generated in this way are then evaluated by means of the evaluation device 60 in order to check the magnetic coding of the security element.

For example, to check the magnetic coding, the magnetic signals are only evaluated to assign the security element to one (of two or more) security element categories. For this purpose, it may be sufficient to determine whether the magnetic signal of a high-coercivity magnetic area h (or possibly also a combined magnetic area k) was detected in any of the measurement tracks L along the security element (multi-code security element) or whether only other magnetic signals were detected (no multi-code -Security element).

To check the magnetic coding, the magnetic signals of the security element can be evaluated with regard to the presence of the individual previously described magnetic areas h, 1 (and possibly also k) on the security element. If the spatial resolution of the magnetic detector 50 is correspondingly large compared to the length of the magnetic areas of the magnetic coding, the magnetic signals can also be evaluated to identify each individual magnetic area and the sequence and arrangement of the magnetic areas on the security element in order to check the magnetic coding of the security element 31.

In Figure 3a For example, the magnetic signal M ₁ is shown, which the respective inductive measuring head of the magnetic detector 50 generates as a function of time t or as a function of the position x along the document of value transported past (at the magnetic detector 50) when a low-coercivity magnetic region 1 is transported past it (differential circuit of the two measuring coils 51). In Figure 3b the corresponding magnetic signal M _h is shown, which the respective inductive measuring head generates when a high-coercivity Magnetic area h is transported past it. In Figure 3c the corresponding magnetic signal M _k is shown, which the respective inductive measuring head generates when a combined magnetic region k is transported past it. And in Fig. 3d the corresponding magnetic signal M ₀ is shown, which is detected in a measurement track L that lies outside the magnetic areas of the security element (offset in the y direction), but in the vicinity of the magnetic areas.

The exact form of the magnetic signals from the individual magnetic areas depends on the type of magnetic detector used. In the Fig. 3a-d The magnetic signals shown in the magnetic areas 1, h and k have a complex structure made up of several minima and maxima. The complexity of these magnetic signals is due to the measurement technology used, in which two inductive measuring heads are connected in a differential manner. The difference between the magnetic signal M ₁ of the low-coercivity magnetic region 1 compared to the magnetic signal M _h of the high-coercivity magnetic region h is essentially based on its reverse magnetization (generated by the magnetic field region 16).

However, the magnetic field of the magnet 52 located between the measuring heads also influences the shape of the magnetic signals, since this magnetic field leads to a remagnetization of the low-coercive magnetic material during the detection process or between the detection processes of the two measuring coils 51. This applies in particular to the magnetic signal M _k of the combined magnetic region k, which is magnetized by the second magnetic field region 16 in such a way that its magnetization resulting from the first and second magnetization almost disappears. Before the start of the measurement of the first measuring coil 51, there is hardly any magnetization of the combined magnetic area k, but after the first measuring coil 51, the magnet 52 generates a resulting magnetization through the above-mentioned magnetization reversal of the low-coercive magnetic material between the detection processes of the two measuring coils 51.

The magnetic signal M ₀ also has maxima and minima, but has a significantly lower amplitude than the other magnetic signals in which the respective magnetic area has exactly hit the respective measurement track in the y-direction. In order to exclude a misjudgment of the (too) low maxima and minima of the magnetic signal M ₀ , the absolute value of the strongest maximum or the strongest minimum of the respective magnetic signal is compared with an insignificance threshold g, cf. Fig. 3a-d . The magnetic detector 50 or the evaluation device 60 can carry out the comparison. If the insignificance threshold g is undershot, as is the case here with the magnetic signal M ₀ , the magnetic signal of the respective measurement track L is ignored for further evaluation. When the insignificance threshold g is exceeded, as is the case here with the magnetic signals Mi, M _h and M _k , the respective magnetic signal is used to check the coding of the security element.

The evaluation device 60, which is programmed with appropriate evaluation software, determines, for example, the strongest two local minima m1, m2 of the respective magnetic signal (the local minima with the largest absolute value) for these magnetic signals Mi, M _h and M _k , which correspond to the respective magnetic signal the respective measurement track L as a function of the position x or the time t in the area of the security element. By comparing the amplitude of the magnetic signal in the second strongest local minimum m2 with the amplitude of the magnetic signal in the strongest local minimum m1, the evaluation device 60 determines a minimum comparison value of the respective measurement track, for example a minimum ratio v=m2/m1 or v=m1/m2 or a minima difference u=m1-m2 or u=m2-m1. In order to check the magnetic coding of the security element, the minimum comparison values v or u of several measurement tracks L are evaluated.

Alternatively or in addition to the minima evaluation, the evaluation device can also carry out a maxima evaluation, in which it determines the strongest two local maxima M1, M2 of the respective magnetic signal (the local maxima with the largest absolute value) and by comparing the amplitude of the magnetic signal in second strongest local maximum M2 with the amplitude of the magnetic signal in the strongest local maximum M1 determines a maximum comparison value of the respective measurement track L, e.g. a maximum ratio V = M2 / M1 or V = M1 / M2 or a maximum difference U = M1-M2 or U=M2-M1. In order to check the magnetic coding of the security element, the maximum comparison values V or U of several measurement tracks L can be evaluated alone or can be evaluated in addition to the minimum comparison values u or v. If necessary, both can also be offset against each other.

In Figure 4a an example of a security element 31 is shown, the magnetic coding of which exclusively has two low-coercive magnetic areas 1. In Figure 4b the minima comparison values v=m2/m1 are shown, which the evaluation device determines from the magnetic signals of an inductive magnetic detector 50 with eight measurement tracks L1-L8 for the security element 31, cf. Fig. 1 . The magnetic signals of the measurement tracks L2, L3 and L6 have minimum comparison values v around 0.25, as expected for low-coercive magnetic areas 1. The magnetic signals of the remaining measurement tracks are below the insignificance threshold g. The minimum comparison values v=m2/m1 of the measurement tracks L2, L3, and L6 are compared with a first threshold t1 stored in the evaluation device 60, which is, for example, about 0.35. Due to the fall below the first threshold t1, it is concluded that the security element has low-coercivity magnetic regions 1 in the (y) sections whose magnetic signals have detected the measurement tracks L2, L3 and L6. The security element 31 Fig. 4a is therefore assigned to a first category, which is designated, for example, "magnetic coding without high-coercive magnetic material" or "no multicode security element".

Fig. 4c is with Fig. 4a identical. In Fig. 4d are for the security element 31 Fig. 4a , c the corresponding maxima comparison values V=M2/M1 are shown, which were determined for the magnetic signals of the measurement tracks L2, L3 and L6. The maxima comparison values V of these measurement traces are in the range 0.7 and thus above a first threshold t1 = 0.55 (differently chosen for the maxima evaluation) with which they are compared. Due to the exceeding of the first threshold t1, it is also concluded in the maxima evaluation that the magnetic signals detected in the measurement tracks L2, L3 and L6 were generated by low-coercive magnetic areas. The security element 31 Fig. 4a , c is therefore also assigned to the first category by the Maxima evaluation ("magnetic coding without a high-coercivity magnetic area" or "no multicode security element").

In Figure 5a (identical with Fig. 5c ) another example of a security element 31 is shown, the magnetic coding of which has two high-coercivity magnetic areas h as well as a low-coercivity magnetic area 1 and a combined magnetic area k. Based on Fig. 5b its minima evaluation and based on Fig. 5d its maxima evaluation is shown.

From the magnetic signals (cf. Fig. 3a-c ) of a magnetic detector 50 with 8 measuring tracks L1-L8 determines the evaluation device 60 for the security element 31 out Fig. 5a , c the minimum comparison values v=m2/m1, cf. Fig. 5b . A minimum comparison value v of approximately 0.25 is determined only for the magnetic signal of the measurement track L3, as is expected for a low-coercive magnetic region 1. Significantly larger minima comparison values v in the range 0.85 are determined for the magnetic signals of the measurement tracks L5 and L7. A minimum comparison value v of approximately 0.45 is determined for the magnetic signal of the measurement track L2 and the magnetic signals of the remaining measurement tracks are below the insignificance threshold g. The minima comparison values v=m2/m1 of the measurement tracks L2, L3, L5 and L7 are also compared here with the first threshold t1=0.35, which is stored in the evaluation device 60 for the minima evaluation. Due to the exceeding of the first threshold t1 in the measurement tracks L2, L5 and L7, it is concluded that the magnetic signal detected there was not generated by low-coercivity magnetic areas, but that the security element must have sections with high-coercivity magnetic material. The security element 31 off Fig. 5a , c is therefore assigned to a second category, which is referred to, for example, as “magnetic coding with high-coercive magnetic material” or “multicode security element”.

The assignment of the security element 31 to the second category can be linked to the condition that the first threshold t1 must be exceeded for the minimum comparison values of at least n measurement traces L so that the security element 31 is assigned to the second category ("multicode security element") becomes. For example, n=2, so that the minimum comparison values must have exceeded the first threshold t1 on at least two of the measurement tracks L so that the security element 31 is assigned to the second category. If, on the other hand, the first threshold t1 is only exceeded on a single measurement track L (ie less than n = 2), the security element 31 - like the security elements without high coercivity Magnetic material - assigned to the first category ("not a multicode security element"). The minimum number n>1 (instead of n=1) is preferably used for testing security elements whose magnetic coding is known to have more than one high-coercivity or combined magnetic region h, k or one or more long magnetic regions h or k. Because n>1 then ensures that a single magnetic signal whose minimum comparison value exceeds the first threshold t1 does not yet lead to the security element being classified as a “multicode security element”, but only when this occurs in at least n measurement tracks L der case is.

If the evaluation device is also to be set up to differentiate between combined magnetic areas k and high-coercivity magnetic areas, a second threshold t2 can be stored in the software with which the minimum comparison values v or the maximum comparison values V are compared. The second threshold t2 is above the first threshold t1 for the minima evaluation, for example at approximately t2=0.65, and below the first threshold t1 for the maximum evaluation, for example at approximately t2=0.4. With the security element off Fig. 5a , c a magnetic signal is detected in the measurement track L2, the minimum comparison value v of which is approximately 0.45 and is therefore above the first threshold t1 and below the second threshold t2, while the minimum comparison value v for the measurement tracks L5 and L7 also exceeds the second threshold exceed t2, cf. Fig. 5b . Based on the determination that a minimum comparison value lying between the two thresholds t1 and t2 is determined for at least one measurement track (here only L2), the security element can be assigned to a third category that may be used ("multicode security element with combined magnetic area"). A corresponding categorization of the security element Fig. 5a , c can also be done using the maxima evaluation, based on the maximum comparison value of approximately 0.45, which also lies between the two thresholds t1 and t2, while the maximum comparison values V for the measurement tracks L5 and L7 fall below the second threshold t2, cf. Fig. 5d .

For a more precise check of the magnetic coding, it can be concluded from falling below the first threshold t1 in the case of the minima evaluation that the security element is out Fig. 4a in the y-sections, which correspond to the measurement tracks L2, L3 and L6, has one or more low-coercivity magnetic areas 1 and in the remaining measurement tracks there is no magnetic material (ie gap areas of the magnetic coding). For the security element Fig. 5a In the case of minima evaluation, it can be concluded from exceeding the first threshold t1 in the measurement tracks L2, L5 and L7 that the security element has one or more high-coercivity or combined magnetic areas in the y-sections that correspond to the measurement tracks L2, L5 and L7 k and - based on the fall below the first threshold t1 in the measurement tracks L3 - that the security element has a low-coercivity magnetic region 1 in the y-section that corresponds to the measurement track L3. The relative or absolute y positions of the low-coercivity magnetic areas 1, the high-coercivity magnetic areas h (and possibly the combined magnetic areas k) of the security element can be compared for a more precise check with reference data which are stored in the evaluation device 60 for several known security elements. Based on this comparison, the magnetic coding can also be checked with regard to the sequence and/or arrangement of the different magnetic areas.

Claims (15)

1. A method for testing a value document (30) comprising a security element (31) having at least one low coercivity magnetic region (1) and/or at least one high coercivity magnetic region (h), the low coercivity magnetic region (1) comprising a low coercivity magnetic material having a first coercivity, and the high--coercivity magnetic region (h) comprising a high-coercivity magnetic material having a second coercivity greater than the first coercivity, the method comprising the steps of:

   - first magnetizing the safety element (31) by a first magnetic field region (15), the magnetic field strength of which is greater than the second coercive field strength, so that the magnetization of the low-coercive magnetic material, if present, and the magnetization of the high-coercive magnetic material, if present, are aligned in a first magnetization direction (x),

   - second magnetization of the safety element (31) by a second magnetic field region (16), the magnetic field strength of which is greater than the first coercive field strength but less than the second coercive field strength, the magnetic field direction of the second magnetic field region being oriented in such a way that the magnetization of the optionally present low-coercive magnetic material is aligned by the second magnetization in a second magnetization direction different from the first magnetization direction,

   - transporting the value document (31) along a transport direction (T) past a magnetic detector (50), which has a plurality of measurement tracks (L) transverse to the transport direction of the value document, in which the magnetic detector in each case detects a magnetic signal (M) as a function of time, wherein

   - the magnetic detector (50) is an inductive magnetic detector, which has, for each measuring track (L), an inductive measuring head with two measuring coils, which are arranged one after the other in the transport direction of the value document and are connected in difference with one another, the difference signal of the two measuring coils being used as the magnetic signal of the respective measuring track, or

   - magnetoresistive elements, AMR, GMR, TMR, or Hall elements are used instead of an inductive magnetic detector, which are electronically connected to each other in difference or whose magnetic signals are subtracted from each other in such a way that the resulting magnetic signal resembles that of an inductive magnetic detector,

   - evaluation of the magnetic signals (M) of the safety element detected by the individual measuring tracks (L), wherein for several of the measuring tracks in each case

   - the strongest two local minima (m1, m2) of the respective magnetic signal and/or the strongest two local maxima (M1, M2) of the respective magnetic signal are determined, which the respective magnetic signal of the respective measuring track has as a function of time,

   - a minimum comparison value (u, v) of the respective measurement track (L) is determined by comparing the amplitude of the magnetic signal in the second strongest local minimum (m2) with the amplitude of the magnetic signal in the strongest local minimum (m1) and/or a maximum comparison value (U, V) of the respective measurement track (L) is determined by comparing the amplitude of the magnetic signal in the second strongest local maximum (M2) with the amplitude of the magnetic signal in the strongest local maximum (M1), and

   - checking a magnetic coding of the safety element using the minimum comparison values (u, v) of several of the measuring tracks (L) and/or using the maximum comparison values (U, V) of several of the measuring tracks (L).
2. The method according to claim 1, characterized in that, when checking the magnetic coding of the safety element for several of the measuring tracks, it is checked in each case on the basis of the minimum comparison value (u, v) and/or on the basis of the maximum comparison value (U, V) of the respective measuring track (L), whether the safety element has a low-coercivity magnetic region or a high-coercivity magnetic region in the respective section whose magnetic signal the respective measuring track has detected.
3. The method according to claim 1 or 2, characterized in that, when checking the magnetic coding of the safety element, a decision is made on the basis of the minimum comparison values (u, v) and/or on the basis of the maximum comparison values (U, V) of a plurality of measuring tracks (L) as to whether the safety element is assigned to a first or a second safety element category.
4. The method according to claim 3, characterized in that the safety element is assigned to a first safety element category if, with a minimum number (n) of measurement traces, the minimum comparison value (u, v) calculated for the respective measurement track exceeds the first threshold (t1) and/or, for a minimum number (n) of measurement tracks, the maximum comparison value (U, V) calculated for the respective measurement track falls below the first threshold (t1), and otherwise the safety element is assigned to a second safety element category.
5. The method according to any of the preceding claims, characterized in that the absolute value of the strongest local minimum (m1) of the respective magnetic signal or the absolute value of the strongest local maximum (M1) of the respective magnetic signal, which the respective magnetic signal of the respective measuring track has as a function of time, is compared with a negligibility threshold (g) and, if the negligibility threshold is exceeded, it is concluded that the safety element has a magnetic region in the respective section of the safety element whose magnetic signal the respective measurement track has detected.
6. The method according to any of the preceding claims, characterized in that the minima comparison value of the respective measurement track (L) is a minima difference (u) between the amplitude of the magnetic signal in the second strongest local minimum (m2) and the amplitude of the magnetic signal in the strongest local minimum (m1) or vice versa, or in that the minima comparison value of the respective measurement track (L) is a minima ratio (v) between the amplitude of the magnet signal in the second strongest local minimum (m2) and the amplitude of the magnet signal in the strongest local minimum (m1) or vice versa.
7. The method according to any of the preceding claims,
   characterized in that the maxima comparison value of the respective measurement track (L) is a maxima difference (U) between the amplitude of the magnetic signal in the second strongest local maximum (M2) and the amplitude of the magnetic signal in the strongest local maximum (M1) or vice versa, or in that the maxima comparison value is a maxima ratio (V) between the amplitude of the magnet signal in the second strongest local maximum (M2) and the amplitude of the magnet signal in the strongest local maximum (M1) or vice versa.
8. The method according to any of the preceding claims, characterized in that for one or more measuring tracks of the magnetic detector, the respective minimum comparison value (u, v) and/or the respective maximum comparison value (U, V) is/are compared with a first threshold (t1), wherein the magnetic coding of the safety element is checked in particular based on whether the minimum comparison value(s) of the respective measurement track (L) exceeds/falls below the first threshold and/or based on whether the maximum comparison value(s) (V) of the respective measurement track falls below/exceeds the first threshold.
9. The method according to claim 8, characterized in that, as a function of whether the minimum comparison value of the respective measurement track exceeds or falls below the first threshold and/or as a function of whether the maximum comparison value (V) of the respective measurement track falls below or exceeds the first threshold, a decision is made as to whether the safety element in the respective section whose magnetic signal has detected the respective measurement track has a high-coercivity or a low-coercivity magnetic region.
10. The method according to claim 8 or 9, characterized in that for one or more measuring tracks of the magnetic detector, the respective minima comparison value (u, v) and/or the respective maxima comparison value (U, V) is/are additionally compared with a second threshold (t2), and in the case that the respective minima comparison value(s) (u, v) and/or the respective maxima comparison value(s) (V) of the respective measuring track lies between the first threshold (t1) and that of the second threshold (t2), it is decided that the safety element in the respective section whose magnetic signal the respective measuring track has detected has a combined magnetic area comprising both the high-coercivity and the low-coercivity magnetic material.
11. A test device for testing a value document (30), which has a security element (31) with at least one low-coercivity magnetic region (1) and/or with at least one high-coercivity magnetic region (h), the high-coercivity magnetic region (h) containing a high-coercivity magnetic material with a second coercivity, the magnetization of which is aligned in a first direction of magnetization, and the low-coercivity magnetic region (1) contains a low-coercivity magnetic material having a first coercivity that is smaller than the second coercivity, the magnetization of the high-coercivity magnetic material being oriented in a first magnetization direction and the magnetization of the low-coercivity magnetic material being oriented in a second magnetization direction that is different from the first magnetization direction,

    wherein the test device (100) comprises:

    - a magnetic detector (50), which is set up to detect magnetic signals of the value document transported past the magnetic detector (50) along a transport direction, the magnetic detector (50) having a plurality of measurement tracks (L) transverse to the transport direction of the value document and being set up to detect a magnetic signal (M) in each of the measurement tracks as a function of time, wherein

    - the magnetic detector (50) is an inductive magnetic detector which has, for each measuring track (L), an inductive measuring head with two measuring coils, which are arranged one after the other in the transport direction of the value document and are connected in difference with one another, the difference signal of the two measuring coils being used as the magnetic signal of the respective measuring track, or

    - magnetoresistive elements, AMR, GMR, TMR, or Hall elements are used instead of an inductive magnetic detector, which are electronically connected to each other in difference or whose magnetic signals are subtracted from each other in such a way that the resulting magnetic signal resembles that of an inductive magnetic detector,

    - an evaluation device (60), which is set up to evaluate the magnetic signals (M) of the safety element, which the magnetic detector (50) detects in the individual measurement tracks (L), the evaluation device being set up for a plurality of the measurement tracks (L) in each case

    - to determine the strongest two local minima (m1, m2) of the respective magnetic signal and/or the strongest two local maxima (M1, M2) of the respective magnetic signal, which determine the respective magnetic signal of the respective measuring track as a function of time, and

    - to determine a minima comparison value (u, v) of the respective measuring track (L) by comparing the amplitude of the magnetic signal in the second strongest local minimum (m2) with the amplitude of the magnetic signal in the strongest local minimum (m1) and/or to determine a maxima comparison value (U, V) of the respective measuring track (L) by comparing the amplitude of the magnetic signal in the second strongest local maximum (M2) with the amplitude of the magnetic signal in the strongest local maximum (M1), and

    wherein the evaluation device (60) is set up to check a magnetic coding of the safety element on the basis of the minima comparison values (u, v) of a plurality of the measurement tracks (L) and/or on the basis of the maxima comparison values (U, V) of a plurality of the measurement tracks (L).
12. The test device (100) according to claim 11, characterized in that the evaluation device (60) is set up, when testing the magnetic coding of the security element for a plurality of the measuring tracks (L), in each case on the basis of the minima comparison value (u, v) and/or on the basis of the maxima comparison value (U, V) of the respective measuring track (L)

    - to decide whether the security element is assigned to a first or a second security element category, and/or

    - to check whether the safety element has a low-coercivity or a high-coercivity magnetic range in the respective section whose magnetic signal has detected the respective measuring track.
13. The test device (100) according to claim 11 or 12, characterized in that the testing device comprises one or more magnets (11, 12) providing a first magnetic field region (15) for first magnetizing of the security element (31) and a second magnetic field region (16) for second magnetizing of the security element (31), which is arranged downstream of the first magnetic field region and upstream of the magnetic detector (50) as viewed along a transport path of the value document through the testing apparatus, wherein the magnetic field strength of the first magnetic field region is greater than that of the second magnetic field region and wherein the magnetic field direction of the second magnetic field region is different from that of the first magnetic field region.
14. A value document processing device comprising

    - a test device (100) according to any of Claims 11 to 13, and

    - a transport device (17) for transporting the value document (31) past the magnetic detector (50) along a transport direction (T).
15. The value document processing device according to claim 14, comprising a test device (100) according to Claim 13, characterized in that the magnets (11, 12) of the test device providing the first and second magnetic field regions (15, 16) are arranged along the transport path of the value document through the value document processing device remote from the magnetic detector (50).

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