Method and device for checking a value document containing a security element comprising at least one magnetic region

Abstract

The invention describes a method for checking a value document transported in a direction of transport and containing a security element that comprises at least one composite magnetic region comprising a hard-magnetic subregion containing hard magnetic material and an adjacent soft-magnetic subregion containing soft magnetic material, the subregions being separated by a strip or adjoining one another along a line, at least part of which strip or line runs obliquely or orthogonally with respect to the direction of transport. The method comprises first magnetization of the composite magnetic region in a first magnetization direction using a first magnetic field, the strength of which is greater than the coercive field strength of the hard magnetic material, and second magnetization of the composite magnetic region in a second magnetization direction using a second magnetic field, the strength of which is less than the coercive field strength of the hard magnetic material, the second magnetization direction differing from the first magnetization direction and preferably being directed counter to the first magnetization direction. During the second magnetization, a magnetic signal of the composite magnetic region is detected by means of a magnetic detector. The magnetic signal is evaluated, this involving checking whether the magnetic signal corresponds to two oppositely magnetized subregions.

Description

[0001] Method and apparatus for testing a security document with a security element having at least one magnetic area

[0002] The invention relates to a method and a device for testing a security document with a security element that has at least one magnetic area.

[0003] Such security features, especially security threads, are used, among other things, in valuables. Valuables are understood to be sheet-like items that represent, for example, a monetary value or an entitlement and should therefore not be easily produced by unauthorized persons. They thus possess features that are not easily manufactured, especially copied, and whose presence is an indication of authenticity, i.e., production by an authorized entity. Important examples of such valuables or types of valuables are chip cards, coupons, vouchers, checks, and especially banknotes.

[0004] To enable automated verification of valuable documents, security features are often designed to be machine-readable; in some cases, security features can only be precisely verified using appropriate sensors. Security features, particularly security threads with machine-readable magnetic areas that can be detected by a suitable sensor, have long been used. The sensor readings can then be used for authenticity verification.

[0005] Based on this, the invention aims to provide a method and a device for testing security features of the type mentioned above, with which valuable documents with such security features can be tested.

[0006] The safety elements to be tested include at least one composite magnetic area comprising a hard magnetic sub-area with hard magnetic material and an adjacent soft magnetic sub-area with soft magnetic material, separated by a line or strip. The sub-areas may be separated by a strip that has no magnetic properties or only very weak magnetic properties. This strip should preferably be narrow, particularly narrower than 0.5 mm, and more preferably narrower than 0.1 mm. However, it is also possible for the sub-areas to border directly on each other along a line. The line is to be considered an idealization; due to manufacturing constraints, both magnetic materials may be present in the area near the line. Preferably, this area is narrower than 0.5 mm, particularly preferably narrower than 0.2 mm, and even better, narrower than 0.1 mm.

[0007] For the purposes of this description, a hard magnetic material is understood to be a magnetic material that exhibits a clearly defined hysteresis curve when exposed to a magnetic field. Preferably, the material displays high remanence and a moderate coercive field strength. Moderate coercive field strength, as used in this description, means in particular that the hard magnetic material has a coercive field strength between 100 Oe (8 kA / m) and 500 Oe (40 kA / m), preferably between 150 Oe (12 kA / m) and 400 Oe (32 kA / m), and most preferably between 200 Oe (16 kA / m) and 300 Oe (24 kA / m). The remanence of the hard magnetic material is expediently between 80% and 20%, and advantageously between 60% and 30% of the saturation magnetization. In the following, a sub-area referred to as hard magnetic is understood to be a sub-area that contains hard magnetic material or magnetic material.

[0008] For the purposes of this description, a soft magnetic material is understood to be a magnetizable material whose hysteresis curve passes through the origin or at least approximately through the origin, such that the coercive field strength and remanence of the soft magnetic material are low. Specifically, the soft magnetic material advantageously has a coercive field strength below 50 Oe (4 kA / m), preferably below 30 Oe (2.4 kA / m), and particularly preferably below 20 Oe (1.6 kA / m). The remanence of the soft magnetic material is advantageously below 30%, preferably below 20%, and particularly preferably below 10% of the remanence of the hard magnetic material used. In the following, a section referred to as soft magnetic is understood to be a section that contains soft magnetic material or magnetic material.The problem is solved by a first method having the features of claim 1 and in particular a method for checking a security document transported in a transport direction with a security element having at least one composite magnetic area comprising a hard magnetic sub-area with hard magnetic magnetic material and an adjacent soft magnetic sub-area with soft magnetic magnetic material, wherein the sub-areas are separated by a strip or adjoin each other along a line, whichwhich runs at least partially obliquely or orthogonally to the transport direction, comprising the following steps: A first magnetization of the composite magnetic area in a first magnetization direction with a first magnetic field whose strength is greater than the coercive field strength of the hard magnetic magnet material, and then a second magnetization of the composite magnetic area in a second magnetization direction with a second magnetic field whose strength is less than the coercive field strength of the hard magnetic magnet material, wherein the second magnetization direction differs from the first magnetization direction and is preferably directed opposite to the first magnetization direction. During the second magnetization, a magnetic signal of the composite magnetic area is detected by means of a magnetic detector.The magnetic signal is then evaluated by checking whether it corresponds to two oppositely magnetized sub-areas.

[0009] The problem is also solved by a first device having the features of claim 14, and in particular a device for testing a valuable document transported in a transport direction, having a security element comprising at least one composite magnetic area comprising a hard magnetic sub-area with hard magnetic magnetic material and an adjacent soft magnetic sub-area with soft magnetic magnetic material, wherein the sub-areas are separated by a strip or adjoin each other along a line which is at least partially oblique or orthogonal to the transport direction, wherein the device successively comprises, along the transport direction of the valuable document: a first magnetizing device for providing a first magnetic field for first magnetizing the composite magnetic area in a first magnetization direction,wherein the magnetic field strength used for the first magnetization is greater than the coercive field strength of the hard magnetic material, a second magnetization device for providing a second magnetic field for the second magnetization of the composite magnetic area in a second magnetization direction with a second magnetic field whose strength is less than the coercive field strength of the hard magnetic material, wherein the second magnetization direction differs from the first magnetization direction and is preferably directed opposite to the first magnetization direction, and a magnetic detector for detecting magnetic signals from the safety element. The device further comprises an evaluation device configured to perform the evaluation step of a first method according to the invention. The first device can preferably be configured to carry out the first method by means of this evaluation device.

[0010] In the first method, two different magnetization processes are carried out. For this purpose, the device includes a first and a second magnetization unit, which provide the first and second magnetic fields, respectively, and each may contain at least one permanent magnet and / or one electromagnet. These are arranged sequentially along a transport path for the valuable document, so that a transported valuable document first passes through the first magnetization unit and then through the second magnetization unit.

[0011] The first magnetization can be carried out using the first magnetization device. This first magnetization can also be referred to as pre-magnetization, since after magnetization with the first magnetic field, which exceeds the coercive field strength of the hard magnetic material, only the hard magnetic portion remains magnetized. Preferably, the first magnetization is performed such that the resulting magnetization of the hard magnetic portion is aligned at least approximately parallel to the transport direction. The first magnetization can be carried out using the first magnetization device, which is designed accordingly.

[0012] The second magnetization process creates a magnetization pattern, but this pattern persists only as long as the second magnetic field acts on the soft magnetic component. Since the strength of the second magnetic field is lower than the coercive field strength of the hard magnetic material, its direction does not change. The soft magnetic material, however, is magnetized in the second magnetization direction, which differs from the first. Preferably, it is oriented opposite to the first magnetization direction, with the angle between the magnetization directions being between 90° and 270°, preferably between 170° and 190°, and particularly preferably between 175° and 185°. The second magnetization process can be carried out using a second magnetization device, which is designed accordingly. In particular, it is arranged downstream of the first magnetization device when viewed in the direction of transport.

[0013] During the second magnetization, and thus while the soft magnetic sub-area is magnetized, a magnetic signal of the composite magnetic area is detected by means of the magnetic detector, thereby generating a corresponding magnetic detector signal.

[0014] The magnetic detector can be inductive or magnetosensitive. A magnetosensitive magnetic detector is one that is sensitive to a static magnetic field or magnetic flux density, and not solely to changes in the magnetic field or magnetic flux density being measured. In particular, a magnetosensitive magnetic detector is not an inductive sensor or detector. Magnetosensitive magnetic detectors can be based on magnetosensitive elements such as magnetoresistive elements, AMR, GMR, TMR, or Hall elements; that is, they incorporate and utilize such elements for detection. The use of magnetosensitive magnetic detectors has the advantage that their orientation and the boundaries of the magnetic sub-areas can be largely independent of each other, yet detection is still possible.A magnetic detector used according to the invention does not directly detect the magnetization in the sub-areas, but rather magnetic fields or magnetic flux densities influenced or generated by this magnetization, or, in the case of inductive sensors, their changes at a distance from the magnetic area specified by the magnetic detector, or certain properties of these fields at that distance. This distance is preferably greater than 1 mm.

[0015] The magnetic signal can, in particular, be a time-dependent variation of a magnetic field strength or magnetic flux density. For a given transport speed, this results in a spatial variation. The magnetic detector signal depends on the magnetic signal and the type of magnetic detector used. In a magnetosensitive magnetic detector, the magnetic detector signal is preferably a monotonic function of the magnetic fields or magnetic flux densities. In an inductive magnetic detector, on the other hand, it is a monotonic function of the derivative of the magnetic signal with respect to time or space. The time dependence corresponds to a space dependence, with both dependencies being related via the transport speed. Therefore, they will not be distinguished in more detail below. Whenever a signal or magnetic signal is mentioned at a specific location below, this means that the signal was detected at and for that location.

[0016] Preferably, the second magnetic field is selected such that the magnitudes of the magnetization of the hard magnetic area and the soft magnetic area are large enough that the corresponding magnetic fields emanating from the magnetized areas can still be reliably detected. However, the magnitude of the magnetization of the soft magnetic area can be smaller than that of the hard magnetic area.

[0017] The detected magnetic signal is then evaluated to determine whether it corresponds to two oppositely magnetized sub-areas. An evaluation signal can then be generated and output or stored, representing the result of the evaluation, particularly the testing. The evaluation can be performed using the evaluation unit of the first device, which may include a processor and memory containing instructions for a computer program. The execution of this program performs the evaluation step.

[0018] One advantage of the first method is that oppositely magnetized areas can be easily and reliably detected. It is also possible to distinguish between magnetic areas that contain magnetic material with the same magnetic properties distributed across the surface. Another advantage is that magnetic signals only need to be detected by a single magnetic detector, meaning the device itself can be correspondingly simple in design.

[0019] The evaluation, and in particular the checking of whether the magnetic signal corresponds to two opposite magnetized sub-areas, can be done in different ways.

[0020] In a first preferred embodiment of the first method, a reference signal profile for the magnetic signal or a magnetic detector signal representing the magnetic signal is provided for testing the contiguous magnetic area. This reference signal profile depends on adjustable parameters, and during testing, the reference signal profile is adapted to the detected magnetic signal or magnetic detector signal by changing the parameters. In particular, the parameters could be adjusted so that the difference between the reference signal profile and the magnetic signal or magnetic signal profile is reduced as much as possible, preferably minimized. The remaining difference between the adapted reference signal profile and the magnetic signal can then be compared with a predetermined limit value to determine whether two oppositely magnetized sub-areas are present.This occurs when the limit value is not exceeded. The evaluation signal can then be generated accordingly.

[0021] In a preferred further development of the first embodiment of the first method, the adapted comparison signal profile or the corresponding parameters are checked to determine whether the composite sub-area has the hard magnetic sub-area at the front in the transport direction or not. Alternatively, a corresponding check can also be performed for the soft magnetic sub-area. Depending on the result, the orientation of the composite area can also be determined as a result of the evaluation, i.e., the sequence of the sub-areas viewed in the transport direction. This enables an even more precise differentiation, even of composite magnetic areas consisting of a hard magnetic and a soft magnetic sub-area.

[0022] In a second preferred embodiment, local extrema of the magnetic signal can be determined during evaluation. It can then be checked whether two local extrema of the same type exist, and preferably whether an extremum of an inverted type lies between the extrema of the same type, and particularly preferably whether the magnitude of the extremum of the inverted type is greater than the magnitudes of the extrema of the same type.

[0023] A local extremum of a signal is understood to be a specific local shape or waveform of the signal. The type of local extremum can be a maximum (peak) or a minimum (trough). An extremum of the inverse type is a minimum (maximum) and a maximum (minimum). The type of extremum—minimum or maximum—depends, among other things, on the direction of the initial magnetization. Extrema of the same type occur at the ends of the composite magnetic region if it contains oppositely magnetized subregions. Therefore, it can also be checked whether the extrema at the ends of the composite magnetic regions lie in a direction parallel to the direction of transport.The extremum of the inverted type, on the other hand, lies in between, as it is caused by the sudden transition from hard magnetic material magnetized in the first magnetization direction to soft magnetic material magnetized in the second magnetization direction in the region of the line or strip. The presence of the extremum between those at the ends is therefore a reliable additional criterion for verifying the presence of a composite magnetic region. Additionally, it can be checked whether the magnitude of the extremum is greater than the magnitudes of extrema of the same type. If this is the case, it is further evidence of the presence of two adjacent, oppositely magnetized sub-regions. This embodiment may require less effort to evaluate than the first embodiment.

[0024] In the second embodiment, the evaluation can preferably further determine which of the extrema of the same type corresponds to a magnetization in the first magnetization direction and / or which of the extrema of the same type corresponds to a magnetization in the second magnetization direction. Depending on the result, an orientation of the composite area can be determined. This orientation can be understood as a sequence of the sub-areas in the transport direction. This allows for an even more precise differentiation of various magnetic areas composed of a hard magnetic and a soft magnetic sub-area. The evaluation result, and thus the evaluation signal, can include the determined orientation.

[0025] In a preferred embodiment, the safety element can have at least one further magnetic area with a high-coercive magnetic material and / or one further magnetic area with a low-coercive magnetic material. Then, in the first method, when evaluating the magnetic signals, it can be checked whether these characteristics or extrema of an inverted type are present at locations corresponding to the ends of the at least one magnetic area, indicating a unidirectional magnetization of the magnetic area, and preferably whether these characteristics or extrema indicate the presence of a magnetic area with a high-coercive magnetic material or an indication of the presence of a magnetic area with a low-coercive magnetic material.The problem is also solved by a second method with the features of claim 6 and, in particular, a method for testing a security document transported in a transport direction with a security element comprising at least one composite magnetic area comprising a hard magnetic sub-area with hard magnetic magnetic material and an adjacent soft magnetic sub-area with soft magnetic magnetic material, wherein the sub-areas are separated by a strip or adjoin each other along a line which is at least partially oblique or orthogonal to the transport direction, comprising the following steps: A first magnetizing orPre-magnetizing the composite magnetic area in a magnetization direction with a first magnetic field whose strength is greater than the coercive field strength of the hard magnetic material, followed by the detection of a first magnetic signal from the pre-magnetized magnetic area by means of a first magnetic detector, a further or second magnetization of the composite magnetic area in a magnetization direction parallel to the magnetization direction during pre-magnetization or first magnetization, preferably in the same magnetization direction as during pre-magnetization or first magnetization, with a magnetic field whose strength is chosen such that the magnetizations of the magnetic sub-areas differ by less than a predetermined maximum value, and during the further magnetization, the detection of a second magnetic signal from the composite magnetic area by means of a second magnetic detector.The next step involves evaluating the first and second magnetic signals, including comparing the extents of the pre-magnetized section of the composite magnetic area and the section magnetized by further magnetization, as a function of the magnetic signals. An evaluation signal can then be generated and output or stored, representing the result of the evaluation, particularly the testing. The phrase "two magnetization directions are parallel" can be understood to mean that the direction encloses an angle of less than 10°, preferably less than 5°, and most preferably less than 2°.

[0026] The problem is also solved by a second device having the features of claim 15, and in particular a device for checking a valuable document transported in a transport direction with a security element having at least one composite magnetic area comprising a hard magnetic sub-area with hard magnetic magnetic material and an adjacent soft magnetic sub-area with soft magnetic magnetic material, wherein the sub-areas are separated by a strip or adjoin each other along a line which runs at least partially obliquely or orthogonally to the transport direction.The device comprises, along a transport direction of the security document, a first magnetizing device for providing a first magnetic field for pre-magnetizing the composite magnetic area in a magnetization direction with a first magnetic field strength greater than the coercive field strength of the hard magnetic material, and a first magnetic detector for detecting magnetic signals from the pre-magnetized security element. It further comprises a second magnetizing device for providing a second magnetic field for further magnetizing the composite magnetic area in a magnetization direction parallel to the magnetization direction during pre-magnetization or first magnetization, preferably in the same magnetization direction as during pre-magnetization or first magnetization.The device comprises a first magnetizing device, a second magnetic field whose strength is selected such that the magnetizations of the sub-areas differ by less than a predetermined maximum value, and at least one second magnetic detector for detecting second magnetic signals of the safety element, wherein the second magnetizing device and the second magnetic detector are arranged and configured such that the second magnetic field acts on the safety element during the detection of the second magnetic signals. Furthermore, the device includes an evaluation device configured to perform the step of evaluating a second method according to the invention. The second device can preferably be configured to perform the second method using the second device.The fact that two magnetization directions run parallel can be understood to mean that the direction includes an angle of less than 10°, preferably less than 5°, and particularly preferably less than 2°.

[0027] The second method involves two sequences of magnetization and detection of magnetic signals. However, this method does not generate opposing magnetizations of the hard and soft magnetic sub-areas.

[0028] In the second method, two different magnetizations are performed.

[0029] The device includes a first and a second magnetization unit, which provide the first and second magnetic fields, respectively, and each may contain at least one permanent magnet and / or one electromagnet. These are arranged sequentially along a transport path for the valuable document, so that a transported valuable document first passes through the first magnetization unit and then the second.

[0030] The pre-magnetization or initial magnetization process is carried out as in the first method; the explanations regarding this process also apply accordingly to the second method discussed here. After pre-magnetization or initial magnetization, the hard magnetic section is magnetized in the first magnetization direction, while the soft magnetic section remains essentially unmagnetized. The explanations regarding the initial magnetization device of the first apparatus also apply to the initial magnetization device of the second apparatus.

[0031] In contrast to the first method, the second device uses a first magnetic detector to detect initial magnetic signals from the composite magnetic area magnetized by the initial magnetization or premagnetization, and thus from the hard magnetic area. The second device therefore has this first magnetic detector, which can be located along the transport path between the magnetizing units. The descriptions of the magnetic detector, magnetic signals, and magnetic detector signals from the first method and the first device apply accordingly to the first magnetic detector, the magnetic signals detected by it, and the corresponding magnetic detector signals.

[0032] After the initial magnetic signals are detected, the composite magnetic area is exposed to a second magnetic field during the subsequent magnetization process. This field causes a second magnetization of the composite magnetic area, in which the hard magnetic and soft magnetic sub-areas exhibit the same magnetization direction. The magnetization direction is essentially parallel to the magnetization direction during pre-magnetization or the first magnetization; preferably, it can be the same as during pre-magnetization or the first magnetization. Furthermore, the strength of the second magnetic field is selected such that the magnetizations of the sub-areas differ by less than a predetermined maximum value. The subsequent magnetization can be carried out using the second magnetization device, in particular the second apparatus, which is designed accordingly.In particular, it is arranged downstream of the first magnetizing device and the first magnetic detector when viewed in the direction of transport. Advantageously, the hard magnetic material and the soft magnetic material of the corresponding magnetic sub-areas are matched to each other such that the magnetization of the hard magnetic sub-areas and the soft magnetic sub-areas of a composite magnetic area is essentially the same at a magnetic field strength HB, which is preferably either between 900 Oe (72 kA / m) and 1500 Oe (120 kA / m), particularly around 1200 Oe (96 kA / m), or between 50 Oe (4 kA / m) and 500 Oe (40 kA / m), preferably between 50 Oe (4 kA / m) and 250 Oe (20 kA / m).

[0033] Such a tuning eliminates the otherwise present signal peak at the interface between the hard magnetic sub-area and the soft magnetic sub-area when the magnetic signal is detected in a magnetic field of strength HB.

[0034] During further magnetization, a second magnetic detector is used to detect second magnetic signals from the magnetized composite magnetic area, and thus from the hard magnetic area and the soft magnetic sub-area, which is also magnetized in the same direction. The second device includes this second magnetic detector. The descriptions of the magnetic detector, magnetic signals, and magnetic detector signals of the first method and the first device apply accordingly to the second magnetic detector, the magnetic signals detected by it, and the corresponding magnetic detector signals.

[0035] In principle, the two sequences of magnetizing and detecting are interchangeable; therefore, the claim does not define an order by using the terms "first" and "second." Furthermore, in the device, the order of the section "first magnetizing device and first magnetic detector" and the section "further magnetizing device and second magnetic detector" is interchangeable. This claim also therefore does not define an order.

[0036] In the following evaluation of the first and second magnetic signals, the extent of a pre-magnetized section of the continuous magnetic region, typically the hard magnetic sub-region, is compared with the extent of the section of the continuous magnetic region magnetized by further magnetization, typically the hard and soft magnetic sub-regions. Since the sub-regions border the strip or line, which runs at least partially obliquely or orthogonally to the direction of transport, the magnetized section of the combined magnetic region is essentially determined by the two sub-sections, while the pre-magnetized section of the combined magnetic region is essentially determined only by the extent of the hard magnetic region.If a significant difference is detected, an indication of the presence of a composite magnetic area with a hard magnetic and a soft magnetic sub-area is generated; otherwise, no such indication is given. An evaluation signal can then be generated and output or stored, representing the result of the evaluation, particularly the testing. The evaluation can be performed using the evaluation unit of the second device, which may include a processor and memory containing instructions for a computer program. The execution of this program performs the evaluation step of the second method.

[0037] The evaluation of the magnetic signals can be done in different ways.

[0038] In a first preferred embodiment of the second method, the extent of the premagnetized section of the composite magnetic area is determined from the first magnetic signal and the extent of a magnetized section of the composite magnetic area is determined from the second magnetic signal, and the determined extents are compared.

[0039] During evaluation, a distance between extrema of inverted type can preferably be determined to ascertain their extents, and this distance can then be used as the extent for comparison. The explanations regarding the terms "extrema" and "inverted type" from the first method also apply here.

[0040] Preferably, the hard magnetic material and the soft magnetic material of the respective sub-areas are matched such that the magnetization of the hard magnetic sub-areas and the soft magnetic sub-areas of a composite magnetic area is substantially the same at a magnetic field strength HB, which is preferably either between 900 Oe (72 kA / m) and 1500 Oe (120 kA / m), particularly around 1200 Oe (96 kA / m), or between 50 Oe (4 kA / m) and 500 Oe (40 kA / m), more preferably between 50 Oe (4 kA / m) and 250 Oe (20 kA / m). The two magnetizations differ, in particular, by less than a predetermined maximum value. "Substantially the same" means, in particular, that the difference between the two magnetizations at the magnetic field strength HB is less than 20%, preferably less than 10%, of the larger magnetization value.Such a tuning means that when the composite magnetic area is detected in a magnetic field of strength HB, a magnetic signal peak that would otherwise be present at the line or strip between the hard magnetic and soft magnetic sections is either completely absent or barely perceptible. The strength of the second magnetic field can then be selected accordingly.

[0041] In the second method, it is then preferably possible to check during evaluation whether the second magnetic signal between the mutually inverted extrema is essentially structureless. An essentially structureless course is understood to mean that the magnetic signal has no or only weakly pronounced, immediately adjacent or overlapping mutually inverted extrema with a maximum magnitude of less than 30%, preferably 20%, of the magnitudes of the mutually inverted extrema. This further development has the advantage that not only can the presence of a soft magnetic sub-region be checked, but also whether the magnetic properties of the sub-regions are so well matched that a substantially uniform magnetization results throughout the composite sub-region.

[0042] In another embodiment, during evaluation, a comparison signal profile for the magnetic signal or a magnetic detector signal reproducing the magnetic signal can be specified for the contiguous magnetic area with consistently uniform magnetization. This profile depends on adjustable parameters, and during testing, the comparison signal profile is compared with the detected magnetic signal or magnetic detector signal by adjusting the parameters to adapt the comparison signal profile to the magnetic signal or magnetic detector signal, and the magnitude of any remaining deviation between the adapted comparison signal profile and the magnetic signal or magnetic detector signal is compared with a predetermined maximum value.If the deviation remains below this maximum value, it is recognized that no further structure exists between the extrema of the inverted type and that there is an indication of the presence of a magnetic area composed of a hard magnetic sub-area and a soft magnetic sub-area.

[0043] In a preferred further development of the two methods, the previously described process steps can be carried out for parallel tracks that are spaced apart perpendicular to the direction of transport. In particular, the magnetic signals, i.e., the first and, if detected, second magnetic signals, can be detected for locations along parallel tracks perpendicular to the direction of transport. Magnetization is carried out in the same way for these tracks. This has the advantage that the position of the security feature in a direction perpendicular to the direction of transport does not need to be defined within narrow limits. Furthermore, it makes it possible to check for the presence and type of magnetic areas for each of the tracks and to determine from the result whether detected magnetic areas represent a predefined code. Under a code, or...In this context, a coding is understood to mean the presence of a predetermined sequence of predetermined magnetic areas, for example by the type of magnetic areas and their relative position to each other, preferably with a predetermined orientation in the case of composite magnetic areas.

[0044] Preferably the tracks have a spacing of less than 15 mm, preferably less than 2 mm.

[0045] In these devices, the first and, if present, the second magnetic detector can be configured to detect magnetic signals for several tracks running parallel to and perpendicular to the transport direction, and for this purpose preferably comprise several inductive or, more preferably, magnetosensitive elements spaced apart from each other perpendicular to the transport direction. The inductive or, more preferably, magnetosensitive elements can be arranged at a distance of less than 15 mm, preferably less than 2 mm, from each other perpendicular to the transport direction.

[0046] In a further development of the method, the security element can further comprise at least one high-coercive and / or at least one low-coercive magnetic area, spaced apart from each other transversely to the transport direction. The relative position of the detected magnetic areas transversely to the transport direction, and preferably, in the case of composite magnetic areas, their orientation, can then be compared with predefined code information. Depending on the comparison, a comparison signal is generated and emitted, indicating the presence of a code defined by the code information. This further development allows valuable documents to be detected based on a code on the security element using magnetic areas, in particular composite and low- and / or high-coercive magnetic areas.This advanced training has the advantage that valuable documents, where the magnetic areas are arranged along a direction perpendicular to a longitudinal direction of the document, can be checked even at high transport speeds, and the position of the security element in the given orientation does not need to be precisely defined. The evaluation unit of the devices must then be designed to also perform this process step.

[0047] In another refinement of the method, the security element can further comprise at least one high-coercive and / or at least one low-coercive magnetic area, and the relative position of the detected magnetic areas parallel to the transport direction, and preferably in the case of composite magnetic areas, their orientation, can be compared with predefined code information. Depending on the comparison, a comparison signal can then be generated and emitted, indicating the presence of a code defined by the code information. This refinement also allows valuable documents to be detected based on a code on the security element using magnetic areas, in particular composite and low- and / or high-coercive magnetic areas.It is particularly suitable for valuables where the magnetic areas are arranged at least approximately parallel to the longitudinal direction of the valuables, and which are transported during inspection with their longitudinal direction perpendicular to the transport direction, i.e., in transverse transport. This has the advantage that, depending on the arrangement of the security elements, only a few magnetic detectors are needed. The evaluation unit of the devices can then be designed to also perform this process step.

[0048] The invention will be explained in more detail below with reference to the drawings. Figure 1 shows a schematic representation of a section of a security document with a

[0049] Safety feature in the form of a safety thread with different magnetic areas;

[0050] Fig. 2 A,E> schematic representations of a first example of an arrangement with a transport device and a test device for testing the magnetic areas of the security feature of the security document transported with the transport device in Fig. 1 in side view and top view;

[0051] Fig. 3 shows a rough schematic flow diagram of a first example of a method for testing magnetic areas using the device in Fig. 2A,B;

[0052] Fig. 4A, 4B shows a schematic representation of the magnetization of the composite magnetic area in Fig. 1 after the first and second magnetization, respectively.

[0053] Fig. 5A, B schematic representations of magnetic signals of the composite magnetic area in Fig. 4A and 4B, that is, before and during the second magnetization, respectively.

[0054] Fig. 6 shows a schematic representation of the magnetization of a high-coercivity magnetic area during the second magnetization.

[0055] Fig. 7 shows a schematic representation of magnetic signals from the magnetic range in Fig. 6.

[0056] Fig. 8 shows a schematic representation of the magnetization of a low-coercive magnetic region during the second magnetization.

[0057] Fig. 9 shows a schematic representation of magnetic signals from the magnetic range in Fig. 6.

[0058] Fig. 10A, B schematic representations of a second example of an arrangement with a transport device and a test device for checking the magnetic areas of the security feature of the valuable document transported by the transport device in Fig. 1 in side view and top view, Fig. 11 a rough schematic flow diagram of a second example of a method for checking magnetic areas using the device in Fig. 10A, B,

[0059] Figs. 12A, 12B show a schematic representation of the magnetization of the composite magnetic area in Fig. 1 after the first and second magnetization, respectively.

[0060] Figs. 13A, 13B schematic representations of magnetic signals of the composite magnetic area in Figs. 12A and 12B, that is, before and during the second magnetization, respectively.

[0061] Fig. 14 shows a rough schematic flowchart of a third example of a method for testing magnetic areas using the device in Fig. 2A, B.

[0062] A security document 2, only partially shown in Fig. 1, has a security element 6, in this example a security thread, on or in a substrate 4. The security thread 6 has at least one composite magnetic area 8 with two adjacent sub-areas 10 and 12 made of magnetic material with different magnetic properties. The security thread 6 runs transversely to a longitudinal edge L of the security document 2. In addition to the composite magnetic area 8 with two sub-areas, the security element or security thread also has further magnetic areas that are not divided into sub-areas but each have essentially uniformly distributed magnetic materials over their surface and thus the same magnetization properties. In this example, the further magnetic areas comprise a high-coercivity magnetic area 13 and a low-coercivity magnetic area 15.

[0063] The composite magnetic region 8 comprises two adjacent subregions 10 and 12, one of which, hereinafter referred to as the hard magnetic region 12, comprises hard magnetic material distributed over a surface, and the other, hereinafter referred to as the soft magnetic region 10, comprises soft magnetic material distributed over a surface. In this example, the hard magnetic material has a coercive field strength between 100 Oe (8 kA / m) and 500 Oe (40 kA / m), preferably between 150 Oe (12 kA / m) and 400 Oe (32 kA / m), and particularly preferably between 200 Oe (16 kA / m) and 300 Oe (24 kA / m). As can be seen in Fig. 1, the subregions are bordered by a line Z. In other embodiments, the sub-areas can be separated by a strip that has no magnetic properties and is in particular narrower than 0.5 mm, preferably narrower than 0.1 mm.In the present case, line Z runs straight and at an angle of approximately 45° to the edges of the magnetic area 8; however, in other embodiments, the angle can be larger or smaller. It is also possible that the line does not run straight.

[0064] The security document 2 in Fig. 1 can be tested using an arrangement roughly schematically illustrated in Figs. 2A and 2B. Fig. 2A shows the arrangement schematically in a view transverse to the transport direction and parallel to a transport plane along which a security document is transported. Fig. 2B, on the other hand, shows the same arrangement in a view orthogonal to the transport plane. The arrangement comprises a transport device 18 for transporting individual or isolated security documents 2 along a transport path 20 in a transport direction T. The transport device 18 is configured for transporting security documents in longitudinal transport, i.e., in an orientation in which a longer edge L of the security document is parallel to the transport direction T, and thus, in this example, the security element 6 is oriented transversely to the transport direction T.In the area of ​​the transport path, a device 22 for checking a security document with a security element 6 with at least one composite magnetic area, which includes adjacent sub-areas with hard magnetic and soft magnetic material, for example of the security document 2 in Fig. 1, is arranged.

[0065] The test device 22 comprises, along the transport path 20 and the transport direction T, a first magnetizing device 24, a second magnetizing device 26 and a magnetic detector 28. The test device 22 further comprises an evaluation device 30, which is connected to the magnetic detector 28 via a signal connection in order to detect and evaluate magnetic detector signals generated and emitted by the latter.

[0066] The transport device 18 has, in this example, at least two, here three, transport belts 31, between which a valuable document can be clamped and then transported, corresponding rollers 32 for guiding the transport belts, and a drive (not shown) that drives one of the rollers 32. The first magnetizing device 24 serves to provide a first magnetic field, which is designed to magnetize a magnetic area, in this example the composite magnetic area 8 and thus the magnetic material of the sub-areas 10 and 12, in a first magnetization direction Mi. For this purpose, it generates, at least in the area of ​​a corresponding section of the transport path, a first magnetic field 34 in the direction of the transport direction T with a magnetic field strength that is greater than the coercive field strength of the hard magnetic material. After passing the first magnetizing device, as shown in Fig.Figure 4A illustrates the magnetization of the hard magnetic sub-area 12, but the magnetization of the soft magnetic sub-area 10 disappears.

[0067] The second magnetizing device 26 serves to provide a second magnetic field 36, which is used to magnetize the magnetic area, in this example the composite magnetic area 8, and also the soft magnetic material, in a second magnetization direction M2. The second magnetization direction is oriented opposite to the first magnetization direction Mi. For this purpose, the second magnetizing device generates a magnetic field 36, at least in the region of a corresponding section of the transport path, with a direction opposite to that of the magnetic field 34 of the first magnetizing device 24 and with a magnetic field strength that is less than the coercive field strength of the hard magnetic material. For this reason, the second magnetizing device does not change the direction of magnetization of the hard magnetic material, and in particular of the magnetic sub-area 12.The soft magnetic sub-area 10, on the other hand, is magnetized in a direction opposite to the magnetization direction of the hard magnetic sub-area.

[0068] The magnetizing devices 24 and 26 are designed to generate magnetic fields across the entire width of the security document 2 and the length of the security feature 6, respectively. In this example, they contain permanent magnets; in other examples, electromagnets could also be used.

[0069] The magnetic detector 28 serves to detect magnetic signals of the safety feature 6 and, in particular, the magnetic areas of the safety feature after passing through the first and second magnetizing devices 24 and 26, respectively, and thus after the first and second magnetization by means of the corresponding magnetizing devices 24 and 26. The magnetic detector 28 is a magnetosensitive magnetic detector which, in this embodiment, has several magnetosensitive elements 38, in this example Hall elements, arranged along a direction transverse to the transport direction T. These are designed and arranged such that they are sensitive to components of magnetic fields or magnetic flux densities that are at least approximately orthogonal to the transport plane in which the section of the safety feature 6 detected by the magnetic detector 28 is located during detection.When a valuable document 2 is transported along transport path 20 in transport direction T past the magnetic detector 28, magnetic signals are detected along tracks parallel to the transport direction. Each of these tracks corresponds to one of the magnetosensitive elements 38 and is therefore spaced apart in a direction transverse to the transport direction. The magnetosensitive elements are arranged at a distance of approximately 1 mm in this example, resulting in a corresponding track spacing of approximately 1 mm. Unlike the figures shown, the magnetic detector 28 in this example is designed to detect magnetic signals across the entire width of the valuable document 2 and thus the length of the security element 6. For this purpose, it has a corresponding number of magnetosensitive elements 28. The magnetic signal is a temporal profile of a component of the magnetic flux density generated by the magnetized security element, detected by the element.The magnetic detector emits magnetic detector signals for detected magnetic signals. These signals are a monotonic function of the component's magnitude and thus reflect the component's behavior. The time dependence corresponds to a spatial dependence, with both dependencies related via the transport velocity. Therefore, they will not be distinguished in more detail below.

[0070] The evaluation unit 30 is designed to perform evaluation steps of the procedure described below for checking a security document moving in a transport direction, which has a security element, preferably a security thread, with magnetic areas. For this purpose, the evaluation unit 30 is connected to the magnetic detector 28 via a data connection for transmitting magnetic detector signals and has at least one processor 44 and a memory 46 in which at least one computer program for evaluating signals or data from the magnetic detector 28 is stored. When the computer program is executed, corresponding evaluation steps of the procedure described below are carried out.

[0071] In the procedure roughly schematically illustrated in Fig. 3, the valuable document is transported by the transport device 18 along the transport path 20 in a transport direction T or in a transport plane at a predetermined transport speed.

[0072] In step S10, a first and a second magnetization of the security feature 6, in particular of a magnetic area of ​​the security feature, in this example the composite magnetic area, are carried out, resulting in a magnetization pattern in which areas with hard magnetic material are magnetized in a different direction than areas with soft magnetic material. The process is illustrated in Figures 4A and 4B, where arrows in the magnetic areas or magnetic sub-areas 10, 12 indicate the direction of magnetization.

[0073] Initially, a first magnetization occurs through a first magnetic field whose field strength is greater than the coercive field strength of the hard magnetic material, thus aligning the magnetization of the hard magnetic material in a first magnetization direction. For this purpose, the magnetic area is exposed to the first magnetic field by transporting the valuable document past the first magnetization device. This magnetization of the hard magnetic material in a first direction occurs. The soft magnetic portion is also magnetized but loses its magnetization again when it is transported out of the area of ​​the first magnetic field. After the first magnetization, only the hard magnetic portion, as illustrated in Fig. 4A, exhibits magnetization in the first direction Mi.

[0074] After the valuable document is transported further, it undergoes a second magnetization by a second magnetic field generated by the magnetizing device 26. This second magnetic field strength is lower than the coercive field strength of the hard magnetic material. The second magnetic field magnetizes the soft magnetic section 12. The second magnetic field is oriented such that the magnetization of the soft magnetic material is oriented opposite to, preferably antiparallel to, the first magnetization direction. The direction of magnetization of the hard magnetic material remains essentially unchanged, as the coercive field strength necessary for a change in direction is not reached. Therefore, as illustrated by arrows in Fig. 4B, the sections exhibit opposite magnetization.The following step S12 involves detecting the first magnetic signals of at least one magnetic area 8 using the magnetic detector 28, while the second magnetization is still ongoing, and while at least the soft magnetic sub-area 10 is still exposed to the second magnetic field. When the security feature 6 passes the magnetic detector 28 during transport of the valuable document 2, the detector detects the first magnetic signals. Given a known transport speed, the corresponding spatial profile of the magnetic signal is derived from its temporal progression. The corresponding magnetic detector signals are then transmitted to the evaluation unit 30.

[0075] The magnetization of magnetic sub-areas 10 and 12, respectively, generates a magnetic field for whose components orthogonal to plane E and the plane of the security document, respectively, within the area of ​​the security feature, the magnetic detector 28 is sensitive. The magnetic signal for a trace is schematically illustrated in Fig. 5B, assuming that the trace runs in the center of magnetic area 8. Fig. 5 shows the magnetic signal m as a function of location x, where m and x are given in arbitrary units. These locations correspond to the locations of sub-areas 10 and 12 in Fig. 4B.

[0076] In Fig. 5B, the magnetic signal is illustrated in a highly idealized form. At locations corresponding to the ends Ei and E2 of the magnetic region 8, parallel to the transport direction T and thus to the corresponding ends of the magnetic subregions, the magnetic signal exhibits characteristics of the same type, namely in the form of local extrema, in this example a minimum and a trough 50. The magnitude of the characteristic is described, in the case of local extrema, by the magnitude of the extremum value, and in the case of a maximum or minimum, by the magnitude of the maximum or minimum value, respectively, as a parameter of the characteristic. The magnitude or parameter, i.e., the respective values ​​of the minima and their magnitudes, of the two subregions can differ because the magnetizations in the subregions are different.Between the two characteristics, and thus the aforementioned ends, a third characteristic of a different type is found at a location C corresponding to line Z. This third characteristic is inverted from the type of the two characteristics corresponding to the ends and takes the form of a local extremum, namely a local maximum or peak. 52 The corresponding parameter of the third characteristic, i.e., the magnitude of the highest value, is significantly larger than the parameters of the characteristics at the ends, i.e., the magnitude of the lowest values ​​or minima. Step S14 involves evaluating the magnetic signals. In a first check, it is determined whether these characteristics of the same type, namely local extrema, are present at a first or second location Ei or E2, respectively, corresponding to the ends of at least one magnetic region.

[0077] The presence of the characteristics can be verified by comparing magnetic signal values. However, it is also possible to fit parameters of a suitable function of position—in the example of an extremum, for instance, a parabola—to the shape of the magnetic signal and thus determine the parameter describing the characteristic. In this way, the presence of the characteristic and its location can be determined. In the example, two extrema of the same type, namely minima, are found, which is interpreted as an indication of the presence of a magnetic region composed of a hard magnetic and a soft magnetic material.

[0078] Furthermore, an optional second test determines whether these magnetic signals exhibit a third characteristic, in this case a local extremum, at a third location situated between the first and second locations. In this embodiment, it is specifically checked whether the type of characteristic is inverted compared to that of the characteristics at the ends: If the characteristics at the ends are minima, the type of the third characteristic must be a maximum. It can also be optionally determined whether this location lies near the line where the magnetic sub-regions meet. In the example, a peak 52 is found between the minima 50, which is considered confirmation of the result from the previous step.

[0079] Furthermore, it is optionally determined whether the extrema 50 at the ends are minima or maxima. Given a specific transport direction T and the arrangement and orientation of the first and second magnetizing devices 24 and 26, respectively, the direction of magnetization at the ends depends on whether the front section in the transport direction T, i.e., the section that first passes the magnetizing devices 24 and 26 and the magnetic detector 28, is the hard magnetic or the soft magnetic section. Alternatively, or additionally, it can be determined whether the third characteristic is a maximum or a minimum. If the presence of the divided magnetic section is detected, the result of the evaluation also includes the sequence of the magnetic sections parallel to the transport direction or the orientation of the combined magnetic section. In the present example in Fig.4B would therefore recognize that the hard magnetic sub-area is located after the soft magnetic sub-area in the transport direction.

[0080] Depending on the results of the testing and comparison, an evaluation signal is generated that represents the result. In principle, the result of the first test is sufficient to indicate the presence of a composite magnetic area. Preferably, however, the result of the second test is also used, whereby both tests must confirm the presence of the divided magnetic area to obtain overall confirmation of the existence of such a magnetic area. As already explained, if a composite magnetic area is detected, the evaluation signal can additionally indicate the orientation found. Furthermore, the evaluation signal can represent the relative position of the detected magnetic area, for example, by specifying the track for which it was detected.

[0081] Basically optional, since it is not absolutely necessary for the detection of a composite magnetic area, in this example, when evaluating the first magnetic signals in step S16, it can be checked whether the safety feature 6 has a magnetic area that has the same low- or high-coercive magnetic material distributed over the area, i.e., a high-coercive or a low-coercive magnetic area.

[0082] For a high-coercive magnetic region 13, this is illustrated in Figures 6 and 7, corresponding to the representations in Figures 4B and 5B. Since the magnetic region is high-coercive, its magnetization retains the first magnetization direction after passing through the first and second magnetizing devices 24 and 26 (see Fig. 6). The corresponding magnetic signal is illustrated in Fig. 7. Figures 8 and 9 show the magnetization and the magnetic signal accordingly for a low-coercive magnetic region 15. At the ends of the magnetic regions, characteristics of an inverted type appear, in the example as a maximum at the front end E2 of the magnetic region and a minimum at the rear end Ei for a high-coercive magnetic region 13, and as a minimum at the front end E2 of the magnetic region and a maximum at the rear end Ei of the magnetic region for a low-coercive magnetic region 15.During evaluation, it is determined whether the detected magnetic signals exhibit characteristics, specifically extrema, of an inverted type at locations corresponding to the ends of at least one magnetic region. Although this can generally be performed independently of step S14, in this embodiment, step S16 is only carried out if step S14 did not reveal that the first magnetic signals of the investigated traces exhibit characteristics, specifically extrema, of the same type at locations corresponding to the ends of at least one magnetic region.

[0083] The presence and expression of the characteristics can be determined analogously to that in step S14.

[0084] These inverted characteristics indicate a unidirectional magnetization of the magnetic region. The evaluation can then show that a magnetic region with essentially homogeneous magnetic material is present. Additionally, it can be determined whether these characteristics indicate the presence of a magnetic region with a high-coercive magnetic material or a low-coercive magnetic material. Given a specific transport direction and the arrangement and orientation of the first and second magnetization devices, the direction of magnetization at the ends depends on whether the magnetic region is high-coercive and thus magnetized in the first direction, or low-coercive and thus magnetized in the second direction. The direction of magnetization is also correlated with whether a maximum or minimum is present at the front end.The coercivity can therefore be determined through appropriate testing. Alternatively or additionally, the magnitude of the characteristic can be used, since the magnitude of the magnetic signal is greater for a high-coercive region than for a low-coercive region. This magnitude can then be compared to a predefined limit value.

[0085] The evaluation result can then indicate that a high-coercive or low-coercive magnetic region has been found. The evaluation signal can then be generated to reflect this result. Another example of a method for checking a security document with a security feature, roughly schematically illustrated in Fig. 11, differs from the previously described method in that, although two magnetizations are also performed, the first and second magnetic signals are recorded after the first magnetization and during the second magnetization, respectively, and then evaluated. Accordingly, a modified arrangement is used. An example of such an arrangement is illustrated in Figs. 10A and 10B.2A and 2b correspond, wherein the test device 22 is replaced by a test device 22'.

[0086] The test device 22' differs from the test device 22 in that the second magnetizing device 26 is replaced by a second magnetizing device 40, which is arranged in the transport direction T after the magnetic detector 28, and that a second magnetic detector 42 is arranged in the influence area of ​​the magnetic field of the second magnetizing device 40.

[0087] The first magnetizing device 24 is designed to provide a first magnetic field for premagnetizing the composite magnetic area in a magnetizing direction with a first magnetic field whose strength is greater than the coercive field strength of the hard magnetic magnetic material: It is unchanged compared to the first embodiment, it is designated by the same reference numeral and the descriptions relating to it also apply here accordingly.

[0088] Along the transport path, the first magnetic detector 28 follows, for detecting magnetic signals from the safety element pre-magnetized by the first magnetizing device 24. Except for its arrangement with respect to the magnetizing devices, it is designed like the magnetic detector of the first embodiment. It is designated by the same reference numeral, and the descriptions of the first embodiment apply accordingly.

[0089] A second magnetization device 40, shown only schematically in the figures, is shown below. It provides a second magnetic field for further magnetizing the composite magnetic area in the same magnetization direction as during pre-magnetization or initial magnetization. It can comprise at least one permanent magnet and / or one electromagnet. The strength of the second magnetic field thus provided is selected such that the resulting magnetizations of the hard and soft magnetic sub-areas 12 and 10, respectively, differ by less than a predetermined maximum value. The strength can therefore be chosen depending on the hysteresis properties or magnetic susceptibility of the hard and soft magnetic materials. In this example, the maximum value is 20% of the magnetization of the hard magnetic area.

[0090] Furthermore, the test device 22' has a second magnetic detector 42 for detecting second magnetic signals from the safety element. In this example, the magnetic detector is designed like the first magnetic detector and, in particular, has the same number of identically designed detector elements, which are arranged to detect magnetic signals along the tracks provided by the magnetic detector 28.

[0091] The second magnetizing device 40 and the second magnetic detector 42 are designed and arranged such that the second magnetic field acts on the safety element during the detection of the second magnetic signals.

[0092] Evaluation unit 30 has been replaced by evaluation unit 30'. The latter is connected to the two magnetic detectors and is constructed like evaluation unit 30, but has an additional interface for connection to the second magnetic detector 42. Furthermore, instructions for a computer program are stored, the execution of which performs the step of evaluating the first and second magnetic signals described below.

[0093] In step S30, a first magnetization or pre-magnetization takes place using a first magnetic field whose magnetic field strength is greater than the coercive field strength of the hard magnetic material, thus aligning the magnetization of the hard magnetic material in a first magnetization direction. For this purpose, the magnetic area is exposed to the first magnetic field by transporting the valuable document past the first magnetization device. This magnetization of the hard magnetic material in a first direction is achieved. The soft magnetic portion is also magnetized but loses its magnetization again when it is transported out of the area of ​​the first magnetic field. After the first magnetization, only the hard magnetic portion, as illustrated in Fig. 4A and the corresponding Fig. 12A, exhibits magnetization in the first direction Mi.

[0094] In step S32, the first magnetic detector detects the first magnetic signal of the premagnetized magnetic region, of which only the hard magnetic subregion is magnetized at this stage. The resulting magnetic signal is illustrated in Fig. 13A. It has two local extrema 54 of mutually inverted types at the ends of the hard magnetic subregion: a maximum or peak in the region of line Z in Fig. 12A and a minimum or trough at the end Ei. The soft magnetic subregion is no longer significantly magnetized after the first magnetization or premagnetization is complete.

[0095] After the valuable document is transported further, a second magnetization occurs in step S34 by a second magnetic field generated by the magnetizing device 40. This second magnetic field strength is lower than the coercive field strength of the hard magnetic material. The second magnetic field magnetizes the soft magnetic section 10. This second magnetic field is oriented such that the magnetization of the soft magnetic material occurs in the same direction as the first magnetization direction. The direction of magnetization of the hard magnetic material remains essentially unchanged, as the coercive field strength necessary for a change in direction is not reached. Therefore, as illustrated by arrows in Fig. 12B, the sections exhibit the same or at least substantially the same magnetization.The resulting magnetic field generated by magnetization therefore corresponds to that of a magnetic area of ​​the same size with only one magnetic material.

[0096] In step S36, the second magnetic detector 42 detects second magnetic signals of the composite magnetic area while magnetization continues and thus while the second magnetic field acts on the soft magnetic magnetic material.

[0097] The magnetic signals produced by the sub-areas are illustrated in Fig. 13B. As already noted, the magnetic signals essentially correspond to those of a magnetic area with only one magnetized magnetic material and therefore exhibit extrema 56 of an inverted type at the ends Ei and E2, with a minimum at Ei and a maximum at E2 in Fig. 13B. Ideally, the magnetic signal between these extrema is essentially linear, but if the magnetizations of the hard and soft magnetic sub-areas are not perfectly matched, it can also exhibit a structure 58, which, however, has only very small magnetic signal values. Such a structure is illustrated by a dashed line in Fig. 13B.

[0098] In step S36, the first and second magnetic signals are evaluated, whereby an evaluation signal representing the result of the evaluation is generated, stored and output.

[0099] During evaluation, the extents of the pre-magnetized section of the composite magnetic area and the section magnetized by further magnetization are compared as a function of the first and second magnetic signals.

[0100] In this example, the first magnetic signal is used to determine the extent of the pre-magnetized section of the composite magnetic area, and the second magnetic signal is used to determine the extent of a magnetized section of the composite magnetic area. These extents are then compared. For example, it can be checked whether the magnitude of the difference between the extents is greater than a predefined minimum value, or whether the ratio of the smaller to the larger extent is less than another predefined minimum value. The minimum values ​​can be predefined depending on the extents of the sub-areas or the magnetic area as a whole; for example, the minimum value for the magnitude of the difference could be 5% of the specified length of the composite magnetic area used in its manufacture.

[0101] In this example, when evaluating the dimensions, a distance between extrema of inverted type is determined and used as the dimension for comparison. In Fig. 13A and Fig. 13B, the dimension of the hard magnetic area would be given by the distance from C to Ei, and the dimension of the section of the magnetic area magnetized during the second magnetization by the distance from E2 to Ei. In this example, the difference between these dimensions would correspond to approximately 50% of the desired length of the magnetic area during its production. If the dimensions differ sufficiently, this is considered an indication of the presence of a magnetic area formed from a hard magnetic and an adjacent soft magnetic sub-area, and is thus considered a valid evaluation result.

[0102] Optionally, it can also be checked whether the second magnetic signal between the mutually inverted extrema is essentially structureless, meaning it exhibits no or only weakly pronounced, immediately adjacent or overlapping mutually inverted extrema with a maximum value of less than 30%. For this check, the magnetic signal values ​​between the extrema can be examined accordingly. If the absence of a structure is detected, this is considered further evidence of the presence of a magnetic region formed from a hard magnetic and an adjacent soft magnetic subregion. However, if a structure is found, the evaluation result, regardless of the first result, indicates the absence of a magnetic region formed from a hard magnetic and an adjacent soft magnetic subregion.

[0103] To verify a security document with a security feature comprising at least one composite magnetic area, at least one high-coercive and / or at least one low-coercive magnetic area, the methods described above can additionally include a further, generally optional, step S24, in which the presence of a code formed by the magnetic areas is verified. An example of such a method, as a variant of the first method in Fig. 3, is shown schematically in Fig. 14, where identical steps are marked with the same reference numerals. While the evaluation steps in the previously described examples can be performed track by track, in step S24 these results are combined for the tracks. In step S24, the relative position and, if applicable, orientation of the magnetic areas identified as present, perpendicular to the transport direction, are compared with predefined code information.The relative level is determined by the position of the tracks where a respective magnetic area was detected. Depending on the result of the comparison, a comparison signal is generated and emitted, indicating the presence of a code defined by the code information.

[0104] Variants of the procedure need not include steps S16 to S20; the code is then given by the sequence and orientation of the combined magnetic areas. Another example of a procedure for verifying a security document with a security feature comprising at least one magnetic area differs from the previously described example in that the security document is transported in an orientation where the security element is aligned parallel to the transport direction T. The traces then run parallel to the longitudinal direction of the security element 6.

[0105] One or more magnetic areas of the security element 6 are then detected sequentially. For each of the magnetic areas, one of the previously described examples of a method for checking a security document with a security feature having at least one magnetic area is carried out. In a preferred embodiment, the relative position, given by the sequence and, if applicable, orientation of the detected magnetic areas parallel to the transport direction, is compared with predefined code information.

[0106] If the types of magnetic regions found, their relative positions (determined by the sequence), and, preferably in one variant, their orientation, match the specified code information, it is recognized that the code has been found. Depending on the comparison, a comparison signal is then generated and emitted, indicating the presence of a code defined by the code information.

[0107] Another example of a device for verifying a security document with a security feature having at least one magnetic area differs from the previously described embodiments in that the magnetic signals are detected by means of an inductive magnetic detector, and the evaluation in step S14 is replaced by a correspondingly modified evaluation in step S14'. An example of such a device differs from the previously described devices in that the magnetosensitive magnetic detector(s) are replaced by inductive magnetic detectors.

[0108] Valuable document

[0109] substrate

[0110] Safety element / safety thread, composite magnetic area, hard magnetic magnetic section, soft magnetic magnetic section, high-coercive magnetic area, low-coercive magnetic area, combined magnetic area, transport device, transport path, test device, first magnetizing device, second magnetizing device, magnetic detector, evaluation device

[0111] T transport belt rollers first magnetic field second magnetic field magnetosensitive elements second magnetization device second magnetic detector

[0112] processor

[0113] memory

[0114] characteristic

[0115] Characteristic E level

[0116] L Long edge

[0117] My first magnetization direction

[0118] M2 second magnetization direction

[0119] T Transport direction

[0120] Z line

Claims

Patent claims 1. Method for checking a security document transported in a transport direction with a security element comprising at least one composite magnetic area comprising a hard magnetic sub-area with hard magnetic magnetic material and an adjacent soft magnetic sub-area with soft magnetic magnetic material, wherein the sub-areas are separated by a strip or adjoin each other along a line which is at least partially oblique or orthogonal to the transport direction, comprising the steps: - first magnetization of the composite magnetic area in a first magnetization direction with a first magnetic field whose strength is greater than the coercive field strength of the hard magnetic magnetic material, - second magnetization of the composite magnetic area in a second magnetization direction with a second magnetic field whose strength is smaller than the coercive field strength of the hard magnetic magnetic material, wherein the second magnetization direction differs from the first magnetization direction and is preferably directed opposite to the first magnetization direction, - during the second magnetization, a magnetic signal of the composite magnetic area is detected using a magnetic detector, and - Evaluating the magnetic signal includes checking whether the magnetic signal corresponds to two oppositely magnetized sub-areas.

2. Method according to claim 1, wherein, for testing the contiguous magnetic area, a comparison signal profile for the magnetic signal or a magnetic detector signal reproducing the magnetic signal is specified from two oppositely magnetized sub-areas, which depends on adjustable parameters, and during testing, the comparison signal profile is adapted to the detected magnetic signal or magnetic detector signal by changing the parameters.

3. The method of claim 1, wherein local extrema of the magnetic signal are determined during evaluation, and it is checked whether two local extrema of the same type are present and preferably an extremum of an inverted type lies between the extrema of the same type and particularly preferably the magnitude of the extremum of the inverted type is greater than the magnitudes of the extrema of the same type.

4. Method according to claim 1, wherein during evaluation it is checked which of the extrema of the same type corresponds to a magnetization in the first magnetization direction and / or which of the extrema of the same type corresponds to a magnetization in the second magnetization direction, and depending on the result an orientation of the composite area is determined.

5. A method according to one of the preceding claims, wherein the safety element comprises at least one further magnetic area with a high-coercive magnetic material and / or one further magnetic area with a low-coercive magnetic material, wherein, when evaluating the magnetic signals, it is checked whether these extrema of an inverted type have locations corresponding to the ends of the at least one magnetic area that indicate a unidirectional magnetization of the magnetic area, and preferably whether these extrema indicate the presence of a magnetic area with a high-coercive magnetic material or the presence of a magnetic area with a low-coercive magnetic material.

6. Method for checking a security document transported in a transport direction with a security element comprising at least one composite magnetic area comprising a hard magnetic sub-area with hard magnetic magnetic material and an adjacent soft magnetic sub-area with soft magnetic magnetic material, wherein the sub-areas are separated by a strip or adjoin each other along a line which is at least partially oblique or orthogonal to the transport direction, comprising the steps: - Premagnetizing the composite magnetic area in one magnetization direction with a first magnetic field whose strength is greater than the coercive field strength of the hard magnetic magnet material, - Detection of a first magnetic signal from the premagnetized magnetic area using a first magnetic detector, - further magnetization of the composite magnetic area in a magnetization direction parallel to the magnetization direction during pre-magnetization, preferably the same magnetization direction as during pre-magnetization, with a second magnetic field whose strength is selected such that the magnetizations of the sub-areas differ by less than a predetermined maximum value, and during the further magnetization, detection of a second magnetic signal of the composite magnetic area by means of a second magnetic detector, and - Evaluation of the first and second magnetic signals comprising a comparison of the extents of the pre-magnetized section of the composite magnetic area and the section of the composite magnetic area magnetized by further magnetization as a function of the magnetic signals.

7. Method according to claim 6, wherein, when evaluating the first magnetic signal, an extent of the premagnetized section of the composite magnetic area is determined and an extent of a magnetized section of the composite magnetic area is determined from the second magnetic signal, and the determined extents are compared.

8. Method according to claim 7, wherein, during evaluation to determine the extents, a distance between extrema of inverted type is determined and this is used as the extent for comparison.

9. Method according to claim 8, wherein during evaluation it is checked whether the second magnetic signal between the extrema of mutually inverted type is essentially structureless.

10. The method of claim 6, wherein, for the purpose of evaluation, a reference signal profile for the magnetic signal or a magnetic detector signal reproducing the magnetic signal is specified for the contiguous magnetic area with continuous uniform magnetization, which depends on adjustable parameters, and wherein, during testing, the reference signal profile is compared with the detected magnetic signal or magnetic detector signal by adjusting the parameters to adapt the reference signal profile to the magnetic signal or magnetic detector signal and the magnitude of any remaining deviation A comparison is made between an adapted reference signal curve and a magnetic signal or magnetic detector signal with a maximum value.

11. Method according to one of the preceding claims, wherein the magnetic signals are detected for locations along parallel tracks spaced apart from each other transversely to the direction of transport, preferably having a distance of less than 15 mm, particularly preferably less than 2 mm.

12. Method according to claim 11, wherein the safety element further comprises at least one high-coercive and / or at least one low-coercive magnetic area spaced apart from each other transversely to the transport direction, and the relative position of the magnetic areas detected transversely to the transport direction and preferably their orientation is compared with predetermined code information, and depending on the comparison a comparison signal is generated and emitted which indicates the presence of a code defined by the code information.

13. Method according to any one of claims 1 to 11, wherein the safety element further comprises at least one high-coercive and / or at least one low-coercive magnetic area spaced apart from each other parallel to the transport direction, wherein magnetic signals for the magnetic areas are detected, and the relative position of the magnetic areas detected parallel to the transport direction and preferably their orientation is compared with predetermined code information, and depending on the result of the comparison, a comparison signal is generated and emitted which indicates the presence of a code defined by the code information.

14. Device for checking a valuable document transported in a transport direction, comprising a security element having at least one composite magnetic area comprising a hard magnetic sub-area with hard magnetic magnetic material and an adjacent soft magnetic sub-area with soft magnetic magnetic material, wherein the sub-areas are separated by a strip or adjoin each other along a line which is at least partially oblique or orthogonal to the The device, which runs along the transport direction of the valuable document, comprises successively: a first magnetizing device for providing a first magnetic field for the first magnetization of the composite magnetic area in a first magnetization direction, wherein the magnetic field strength used for the first magnetization is greater than the coercive field strength of the hard magnetic material; a second magnetizing device for providing a second magnetic field for the second magnetization of the composite magnetic area in a second magnetization direction with a second magnetic field whose strength is less than the coercive field strength of the hard magnetic material, wherein the second magnetization direction differs from the first magnetization direction and is preferably directed opposite to the first magnetization direction.a magnetic detector for detecting magnetic signals of the safety element, and an evaluation device configured to perform the step of evaluating a method according to one of the preceding claims.

15. Device for checking a valuable document transported in a transport direction with a security element comprising at least one composite magnetic area comprising a hard magnetic sub-area with hard magnetic magnetic material and an adjacent soft magnetic sub-area with soft magnetic magnetic material, wherein the sub-areas are separated by a strip or adjoin each other along a line, whichwhich runs at least partially obliquely or orthogonally to the transport direction, wherein the device comprises successively along a transport direction of the security document: a first magnetizing device for providing a first magnetic field for pre-magnetizing the composite magnetic area in a magnetization direction with a first magnetic field whose strength is greater than the coercive field strength of the hard magnetic material, a first magnetic detector for detecting magnetic signals of the pre-magnetized security element, a second magnetizing device for providing a second magnetic field for further magnetizing the composite magnetic area in a magnetization direction parallel to the magnetization direction during pre-magnetization, preferably in. of the same magnetization direction as in premagnetization, with a magnetic field whose strength is selected such that the magnetizations of the sub-areas differ by less than a predetermined maximum multiplier, and at least one second magnetic detector for detecting second magnetic signals of the safety element, wherein the second magnetizing device and the second magnetic detector are arranged and configured such that the second magnetic field acts on the safety element during the detection of the second magnetic signals, and an evaluation device configured to perform the step of evaluating a method according to one of claims 6 to 13.

16. Device according to one of claims 14 or 15, wherein the first and, if present, second magnetic detector are configured to detect magnetic signals for several tracks running parallel and transverse to the transport direction, and preferably comprise several inductive or preferably magnetosensitive elements spaced apart from each other transversely to the transport direction.

Images