PL178898B1 - Method of and apparatus for checking protected documents - Google Patents

Abstract

1. Method of checking secured documents using capacitive coupling between transmitters and receivers and transmitting energy between transmitters and receivers by bridging the electromagnetic field through electrically conductive strips, tapes, fibers securing documents or flat-shaped securing materials and receiving signals by an attached electronic evaluation system, characterized in that in the area of known optical sensors located in the machine, which are spatially located in accordance with the capacitive sensors operating in the machine and activate these inspection sensors, many of them located in one or more planes antennas acting as transmitting or receiving sensors create checking fields, and the tested object, depending on its geometric shape and/or its conductivity, moves in the field coupling these electromagnetic energy antennas, and moreover, many antennas are controlled at least in different phase positions, and the transmitted the energy is fed to selective amplifiers (14), and in order to reduce the interference energy and to suppress the basic conductivity of the tested objects, for example banknotes, a phase comparator and a special filter for suppressing the interference energy are connected after the selective amplifier (14). and external, as well as an evaluation unit, which are placed so that it is possible to classify electrically conductive strips, tapes, security fibers or flat-shaped security materials, with the tested object being forced through the field during the checking operation checking in an undefined side position. 9. Device for checking secured documents with capacitive coupling elements, transferring energy between transmitters and receivers by bridging an electromagnetic field through electrically conductive strips, tapes, security fibers or flat-shaped security materials and with an electronic evaluation system, characterized in that it has: known optical sensors existing in the machine for activating the capacitive checking sensors; check boxes that are made up of many located in one or ................................... .. P L 178898 B 1 Fig. 1 PL PL PL PL PL PL PL PL PL

Description

The invention relates to a method and devices for checking secure documents using capacitive coupling between transmitters and receivers and transmitting energy between transmitters and receivers by bridging an electromagnetic field through electrically conductive strips, tapes, document filaments or flat-shaped security materials and signal reception by an attached electronic system evaluation of the authenticity of documents.

There are many methods, devices, methods and systems of checking to establish the authenticity of secured documents. DE-PS 1223594 describes a device for capacitive reading of record carriers, in which the read capacitors consist of sensing electrodes arranged on both sides of the record carrier tape. The reliability of reading this device of inserted, pressed on or applied electrically conductive strips, tapes or similar particles in the documents checked has not been given.

DE-PS 1774290 describes a measuring system for automatically evaluating the characteristic of a banknote in a banknote validation device by means of a capacitive coupling of electrodes which are arranged in a mesh. This known measuring system, at the speeds required under the current conditions, does not allow the exact determination of the relevant characteristic and does not detect counterfeiting when using electrically conductive components, for example in banknotes.

DE-OS 2619457 measures the magnetic properties of a control strip contained in a banknote.

178 898

Checking the authenticity of ferromagnetic security fibers in securities by exposure to a magnetic field is described in DE-PS 2834287. These checking methods are too slow and require the precise alignment of the object to be checked or the strip to be checked.

DE-PS 2760165 describes a technically complex checking device in which, in particular in the second part of the checking, the authenticity of the banknotes is determined by measuring the difference in thickness and the fluorescent properties. Checking only these properties no longer corresponds to the status of counterfeits in circulation. Counterfeit money with watermarks and with fluorescent paper or ink can no longer be checked with this device other than with uncertainty.

Also, the reading heads described in DE-OS 3236373 and 3236374 and in others in machines, which together with the markings on secure documents form an electric capacitor, and by introducing ferroelectrics between the capacitive electrodes of such a reading head, a specific change in the capacitance value is not suitable for fast-acting machines and for checking European banknotes currently in circulation.

The testing of electrically conductive security fibers by detuning oscillators and oscillation circuits according to DE 2912712 is not carried out due to the low reliability of the evaluation and the high technical cost and the complex structure.

US 5 308 92 describes a measuring system composed of optical and capacitive sensors which, however, requires precise alignment of the strip to be checked. In order to increase the reliability and distinguish between different test objects (e.g. different currencies), it was additionally proposed to use a magnetic sensor, which makes the measurement system even more complicated and more expensive. After sorting the banknotes, the capacitive sensor only shows the existence of an electrically conductive security fiber.

Also known is a test system according to DE 4103932, by means of which capacitive and / or electro-optical sensors and / or millimeter wave sensors for the test are arranged longitudinally along the test section. The subject of this publication is, inter alia, the study of the electrical properties of banknotes.

DE 43 25 027 describes a method and system for validating bank notes, evaluating the change in field strength when a high-frequency field is bridged by metal security strips. Use in banknote counting machines is only possible at low speeds due to low sensitivity and low interference suppression. In addition, the tested objects are also considered to be weakly conductive and wet. Gaps in the metal strips of real banknotes are not detected, so the machine stops incorrectly. Due to the low sensitivity of the system, the distance between the electrodes and the metal security fibers of the banknotes must be very small, which makes it impossible to use it in high-speed banknote counting machines. The series placing of a plurality of such sensors is only possible with a relatively large distance, so that the sensors do not influence each other.

WO 94/22114 describes a device for recognizing metallic conductive security fibers. Here, too, low-conductive and wet test objects are considered true, as the electrical charging of the sensor electrodes is measured. It is not envisaged to classify differently sized security fibers. EP 0 204 574 describes a method for determining a magnetic print pattern by means of electromagnetic induction. Since the current copiers can already be equipped with magnetically conductive inks, this type of testing in its reliability is strongly limited with the current quality of counterfeits.

The disadvantages of these known checking methods and systems are, in the first place, the high technical costs and their insufficient reliability in finding counterfeits in the rapid throughput of banknotes in the machines. A disadvantage of the known measuring systems for testing capacitive properties is that a sufficiently low capacitive impedance is obtained only in the low frequency ranges of 10-22 kHz envisaged and only at very small intervals.

178 898 between the electrodes and the metal fibers. Moreover, in this frequency range, the influence of the dielectric change is still very great, i.e. a material with a high dielectric constant causes an increase in the capacitance and thus a reduction in the capacitive impedance between the antennas. For example, a wet fake is considered genuine. In practice, these systems have not proved successful so far, especially in machine truth-checking.

EP 5 89 195 A2 describes a method whereby an association code is obtained by means of an evidence signal obtained by examining a read area with highly transmissive magnetic elements and by means of a device with an excitation winding and a sensor winding, and the match code is confirmed to be true when the proof signal and the mapping code match. This method of testing is limited only to magnetic or magnetizable plastic cards, paper documents and is only applicable to a few non-European banknotes. Other methods of testing, such as those described in EP 204 574 A2, 553 402 A1 and 560 023 A1, where the geometric and / or physical properties of the test objects are classified by the comparative method, are suitable for use with only one type of test object, are very expensive and in practice they are not used due to the high speed required in the machines.

The object of the invention is to overcome the existing drawbacks of known test systems and methods and to propose a method that allows reliable recognition of a certain test characteristic, is applicable to many types of banknotes and currencies, also for example with wet or intentionally moistened and / or soiled test items. can distinguish them from each other, requires little technical effort, is suitable for use in existing machines and corresponds to the rapid traverse of the test objects in the machines. An electrically conductive fiber or security strip or a flat-bladed security marking on banknotes and securities is used as a test feature.

Moreover, it is a task to develop a test device for carrying out this method, so that before sorting by currency and type, a validation can already be carried out.

The object of the invention for carrying out the method is furthermore to provide a security document inspection apparatus having an electrically conductive web or fibrous strip as the security element for checking both electrically conductive continuous strips and those strips that include a plurality of electrically conductive areas insulated from each other. An example of such a security document are current US banknotes which have electrically conductive but isolated markings on their security fibers. In current practice, it is necessary to easily install such checking systems on machines, which not only recognize good-quality counterfeits but also genuine, diminished-quality documents, since in practice they occur quite frequently and cause false decisions that significantly disrupt the workflow of the machines.

The method of examining security documents according to the invention envisages, using the known capacitive coupling, that the electrical signals from the transmitting antennas are transferred by the electrically conductive security features of the examined documents to the receiving antennas and are amplified, and then evaluated in terms of the amplitude and time course and compared with the existing ones. waveforms, which are converted into signal waveforms having easily comparable parameters. For carrying out this method with its operating steps, which will be described in more detail, for banknotes, documents, securities, etc. with security stripes or fibers, or with a flat-shaped security feature using a capacitive coupling, a checking device is proposed, which can be used, for example, in a banknote processing machine, preferably a counter. A test sensor in the area of optical and / or magnetic sensors and / or format sensors is provided on the housing assembly. The machine feeds banknotes and / or securities to the checking device. The checking sensor is composed of many an

178 898 this and / or electrodes. These antennas and / or electrodes are arranged transversely to the transport direction of the tested objects that even with a certain lateral slack of the tested object and regardless of whether the tested object passes through the checking device with the front side facing upwards or with the rear side, in any case strips or the security fibers still sufficiently cover the antennas and / or electrodes. The antennas and / or electrodes of the checking unit are positioned in accordance with known guide devices, pinch rollers and / or conveyor belts, so that the documents to be checked during their rapid passing at the antennas are positioned at predetermined intervals and / or pressed against the electrodes. By arranging the checking device according to the invention in the area of optical and / or magnetic sensors and / or format sensors which usually operate to recognize geometric shape, position, color etc., the checking sensor is simultaneously activated.

One or more antennas and / or electrodes are supplied with high and / or low frequency energy and / or direct voltage and one or more antennas and / or electrodes back receive some of the radiated energy through a protective strip or fiber. As a result, the voltage at one or more receiving antennas and / or receiving electrodes changes.

In order to make it possible to issue comparable judgments on checking, for example, the authenticity, suitability for use of documents or banknotes, constant conditions of passage, such as speed, are necessary for the compared checked objects. Antennas and / or electrodes transmit a voltage signal to the electronic evaluation system. This electronic evaluation system produces an easily comparable voltage depending on the shape of the received voltage signal. Special filters and / or phase comparators can be used to suppress the interfering and external energy as well as the influence of the basic conductivity of the tested objects on the measurement result.

The electronic evaluation system output pulse is independent of the passing speed. In order to enable a specific selectivity of the checking device, an additional selective amplifier is coupled to the evaluation electronic circuit. This selective amplifier converts the voltage obtained from the check sensor into an easily comparable voltage, which depends on the amplitude waveform of the voltage received. When defining the electronic evaluation system depending on the category (electrically conductive security strips or security fibers, or any conductive markings), additional amplitude limits are set, the course of which lies so close to the amplitude deviation of the check signal that, based on the difference between the predetermined amplitude limit and the possible the greatest deviation of the amplitude of all the tested objects is marked as truthful. This means that even the most recent counterfeits, which give a signal normally accepted as an evaluation signal, will be designated by the electronic evaluation system according to the invention as a counterfeit.

A currency-specific definition by means of the electronic evaluation system according to the invention, e.g. for all country banknotes with similar security stripes, is achieved according to the invention by the fact that a time limit of the check signal amplitude is determined for the currency, e.g. by means of a controller, which differs on the duration of the amplitude waveform of all other currencies.

In the case of currencies with the same check signal amplitude duration, an additional check is performed, e.g. by color recognition and / or color differentiation and / or by a magnetic method and / or a format checking method. The recognition signals provided by, for example, photocells are combined with the signal of the checking sensor according to the invention and a machine-specific output signal is generated.

A variation of this method is that one or more pairs of transmit antennas are actuated with a phase shift to check secure documents. Due to the capacitive coupling between one of the transmit antennas, the electrically conductive marking on the security strip, and the receive antenna opposite the transmit antenna at the input of the amplifier, a truthfulness signal is generated. The second transmitting antenna, which is controlled in phase with the first, does not result in any capacitive coupling of the signal with the receiving antenna, because in the area of

There is no electrically conductive safety strip. In such an arrangement, it is already possible to check a continuous electrically conductive strip. With respect to these pairs of antennas, further pairs of transmitting and receiving antennas are positioned, whose dimensions and spacing are adapted to the electrically conductive markings of the security strip. By moving the object under test at a certain distance from the sensor that checks the characteristic amplitude and time signals, and thus the evaluable signals are transferred from the receiving antennas to the electronic evaluation system. In this way, an inspection is carried out that is able to recognize and adequately evaluate a plurality of electrically conductive marks that are isolated from each other. It is irrelevant whether the insulation between the electrically conductive marks is intended, e.g. in US banknotes, or whether the insulation is caused e.g. by cracks in electrically conductive security strips manufactured continuously, e.g. in German banknotes. The microcontroller can compare the number of such interrupts with the stored values. By arranging several pairs of transmit and receive antennas and the associated electronic evaluation circuits, a reliable statement about the truthfulness of the document is possible, since it works reliably despite possible lateral shifts when feeding the object to be checked to the checking device. If, according to the invention, the transmitting or receiving antennas are arranged over the entire working width of the machine, it is possible to position neutral checking of the security documents. It is irrelevant whether the document is fed on the front or back side and / or with the securing strips arranged on the left or on the right and / or shifted transversely to the transport direction. As a result, documents can be checked, which may differ both in format and in the positioning of the securing strip in relation to the direction of transport. Due to the different types of security strips, it is also possible not only to classify the truthfulness, but also to specifically allocate different documents, e.g. different currencies.

In the direction of banknote transport, a further checking sensor can be arranged upstream and / or downstream of the checking sensor according to the invention. In this case, the output of this sensor is combined with the output of the checking sensor according to the invention (double checking) without having to change the software for the machine in question, for example by equipping it with a testing device according to the method of the invention.

Advantageous features of the invention result, in addition to the patent claims, also from the description and the drawings, individual features always being shown separately or for several protectable embodiments in the sense of the subordinate combinations for which protection is claimed. Embodiments of the invention are shown in the drawing, in which Fig. 1 shows a block diagram of the evaluation system, Fig. 2 - curves obtained by passing the banknote at different speed of passage, Fig. 3 - obtained currency-specific curves, Fig. 4 - curves obtained for Fig. 5 - a block diagram of the double-checking evaluation system, Fig. 6 - a section through a schematic representation of a checking device, Fig. 7 - a checking sensor, Fig. 8 - a block diagram of a checking device, Fig. 9 - sensor placement checking machine.

The method described in more detail below on the basis of various devices and circuits essentially consists in carrying out the following steps: capacitively coupling the electrical signals from the transmitting antenna through electrically conductive protective materials to the receiving antenna, amplifying and processing received signals of differing amplitudes and time course into easily comparable signals and comparing them with the already existing waveforms of signals in order to demonstrate and assess in an appropriate form the truthfulness of the examined documents. The machine coupled to the checking device transports the banknotes or securities into the area of the checking device. Then the photocells trigger the checking sensors.

178 898

The transmitting antenna is powered by high-frequency energy. In the illustrated embodiment, 6 MHz. When the security strips or fibers pass through the test area, the receiving antenna takes back some of the radiated energy. The high-frequency voltage at the receiving antenna changes. The reason for this is known to be the capacitive coupling between the transmitting antenna and the receiving antenna caused by the electrical conductivity of the security strips or fibers. The high frequency conductivity varies between currencies. In order to be able to obtain currency-specific statements by means of the evaluation system, constant traversal conditions of all test subjects in one operation are necessary.

An electronic evaluation system consisting essentially of an analog-to-digital converter and a controller or integrator 15, a trigger system 16, a controller, a single-stable trigger 17 and possibly a gate 18 is connected to the testing unit and its testing sensors via shielded wires. the evaluation is shown as a block diagram of Fig. 1.

12 denotes a high-frequency transmitter, through 13 a high-frequency receiver that receives the energy radiated from the receiving antenna 9, amplifies it in the selective amplifier 14 as a currency-specific and / or truth-specific utility signal, 15 denotes an integrator, through 16 a trigger circuit, which in addition to of existing signals, it receives the evaluation circuit activation signals of the photocells 20 and transmits them as time-coordinating pulses through the toggle switch 17 as an output signal for test objects determined to be true. As can be seen in Fig. 4, the curves a and b do not result in output signals comparable to the outputs of the genuine banknotes when the banknotes pass from the counterfeit banknotes 26. The specific screening of the research sensors and the electronic evaluation system in relation to electric and electromagnetic fields and the placement of the research sensors in the area of photocells guarantee a high ratio of useful signal to disturbance and allow, in combination with forced guidance through belt conveyors in conjunction with a certain speed of passing banknotes, currency-specific selectivity of the device reviewer. A further advantage of this method according to the invention is that e.g. the moisture content and / or the degree of soiling of the test objects and / or banknotes and / or securities is no longer the main source of disturbance.

Figure 6 shows a schematic cross-section of the checking device. This device is used in a banknote checking machine, preferably in a calculating machine according to the above-described method. At the casing unit 1 there is a machine support 2, on the horizontal arm 3 of which is a checking sensor positioned in the area of the photocells 4, 5 on the non-conductive support material 6 of the arm 3. The support material 6 has cutouts and / or cuts 7 for transmitting light to the photocells 4 5. These cutouts and / or cuts 7 may be redundant if a glass-like support material 6 is used.

The checking sensor is composed of several strip sensors 8,9, in this example two, namely strip sensor 8, being the transmitting antenna, and strip sensor 9, being the receiving antenna. The strip sensors 8, 9 have a plane longitudinal dimension transverse to the transport direction of the banknotes 11 such that, even with a defined lateral play of the banknotes 11 and regardless of whether the banknote 11 passes through the checking device with its front side upwards or its rear side, in any case The security strips or fibers still sufficiently enclose the strip sensors 8, 9 and are guided underneath them through the checking device. Below the arm 3 and parallel to it, the conveyor belts 10 run at such a distance from the strip sensors 8 and 9 that the notes are pressed against the strip sensors 8 and 9 during their rapid passage.

Between the conveyor belts 11 there are photocells 4, 5 perpendicular to the direction of the banknotes passing.

The evaluation electronic system is also arranged in the screen area of the machine, in this embodiment preferably in the area of the housing where, for example, a device for setting the paper thickness is arranged.

178 898

The defined shielding of the check sensor and the electronic evaluation system against electric and electromagnetic fields and the placement of the check sensor in the area of the photocells 4,5 ensure a high useful signal to disturbance ratio and enable in combination with forced guidance through conveyor belts 10 and in combination with a specific currency-specific speed of the banknotes selectivity of the checking device. A further advantage of this testing device according to the invention is that e.g. the moisture content and / or the degree of contamination of the test objects are essentially not a source of disturbance. In the banknote transport direction, a further checking sensor, for example for a magnetic test, as shown in the block diagram in Figure 5, may be arranged upstream or downstream of the checking sensor according to the invention - in this example not shown - the output of this sensor is combined. with the output of the inventive testing sensor (double checking), whereby there is no need to change the software for the machine in question, e.g. when setting up with the inventive testing device.

The evaluation electronic circuit connected to the checking sensor and the photocells provides - as shown in Figs. 2 and 3 - a direct voltage dependent on the amplitude waveform of the received high frequency voltage. This transferred signal, represented by curve a, illustrates this in the mentioned figures.

Figure 2 shows the curves obtained by passing the banknote at different speeds. The curve a shows the transmitted signal and the curve b shows the output signal of the electronic evaluation system. vl corresponds to a pass of 500 banknotes per minute and v2 to pass 1800 banknotes per minute. Curve b further shows how the note recognition signal provided by the photocells is combined with the signal from the checking sensor to generate a machine-specific output pulse. This output pulse is independent of the traversing speed as it appears from the comparison of the b curves in Fig. 2.

Figure 3 shows the currency-specific curves obtained when passing notes of different currencies. Curve a again shows the transferred signal from the checking sensor, while curve b shows the evaluation signal of a selective amplifier which has additionally been coupled to an evaluation electronics to allow the currency specific selectivity of the checking device without additional sensors. In figure 3, DE stands for German currency, CH stands for Swiss currency, EG stands for Egyptian currency and CN stands for Chinese yuan since the 1990 series.

For banknotes of different currencies, clearly recognizable is the different amplitude waveform of the received high-frequency energy expressed by a different type of security strip and as captured by the electronic evaluation system. Should currency specific signal processing be required, then a signal additionally prepared by the evaluation electronic system for the purpose of currency classification, e.g. by means of a controller, is possible. Just as different currencies are distinguished by different security strips or fibers, counterfeits are also recognized if they have imitations of the security strips or fibers, or even just pieces of them. Figure 4 shows the curves for determining eleven banknotes in a banknote counter. Banknotes marked 21-25 and 27-31 are considered genuine. Test object No. 26 is a counterfeit intentionally introduced for trial purposes. Due to the lack of the security strip or due to the imitation of the security strip with sensors, the tester did not give any signal. In practice, in the absence of a signal or with a signal not specific to the banknote, the machine is stopped and the counterfeit or unusable document is removed or specially put away by machine.

If the testing unit is additionally connected to a further testing sensor, this machine-specific output pulse shows the recognition of the security strip or security fiber and is summed (I-gate) with the output of the additional testing machine test. If one of the two true signals is missing, the machine stops and the operator can remove the defective or counterfeit banknote.

178 898

A further possibility of using the electronic evaluation system with appropriate determination results from the evaluation signals of the selective amplifier, which are shown in FIG. is exceeded, then they will be considered at the speed v2 as real security strips or security fibers acting on the testing sensor. Each currency has a specific time t _k . To distinguish between different currencies, the times t _k = t _v ... t ₄ to t _{n have to} be defined specifically for currencies as you

For example, you select the German currency greater than t ₂ Swiss francs, or the t _f Swiss francs should be selected as greater than t ₃ Egyptian currency. Since you of the German currency have to be chosen as equal to those of currencies not shown in Fig. 3 as far as possible, a further currency-specific check is necessary with a known method of color recognition and / or format and / or magnetic machine testing method. The sorted, discrete currencies are arranged in the compartments or containers in a known manner.

Particularly for document testing of discontinuous electrically conductive release strips, the machines are provided with a checking sensor 54 as shown in Fig. 7 which is composed of a plurality of transmit and receive antennas all arranged mutually parallel and perpendicular to the direction. transportation. For the examination of banknotes, they are distributed throughout the passage of the machine, e.g. its length approximately transversely to the direction of transport. The transmitting antennas A2, A3 and the receiving antenna A1 are positioned opposite to each other. Several transmit antennas B2.i (i = 1..n) and several receive antennas BI .i form pairs of antennas. These pairs are offset to each other so as to suppress the coupling pass of the signal from one transmitting antenna Bl.i to the adjacent one, but not to suppress the corresponding receiving antenna Bl.k (k = l ... n, iok). Adjacent transmitting antennas B2.i, B2.i + 1 and associated receiving antennas B1.i, Bl.i + 1 are shifted by a predetermined distance, preferably by a distance between transmit antenna B2.i and the associated receiving antenna B1.i. In order to reduce the interference, the transmitting antennas A2, A3 and the receiving antenna A1 are preferably positioned at an oblique position between them.

Figure 8 shows a block diagram of the checking device according to the invention with the control of the checking sensor according to figure 7. After the document has been fed to the machine which comprises the checking device according to the invention, it is activated by photocells or similar position sensors. The frequency generator 41 controls the transmit antenna A2 and via the phase shifter 42 the receive antenna A3. Thanks to the phase shift control, interference from external energy sources is avoided and counterfeits are detected that do not have any difference in electrical conductivity. This also applies to banknotes whose properties have changed, for example, as a result of aging and / or mechanical damage and / or moisture. Simultaneously, the n number of transmit antennas B2.i (i = l .... n) is driven by the second frequency generator 43 and the second phase shifter 44. The transmitting antennas B2.i are always placed transversely to the transport direction, not in series, they are driven with a phase shift to reduce interference from external energy sources and to avoid capacitive coupling of the transmitting antenna B2.i with a non-corresponding receiving antenna Bl.k (k = l. ..n, iok). The signal frequencies of both generators are chosen so that one frequency is not a multiple of the other or a multiple of the difference between them, in order to avoid signal falsification at the receiving antennas.

During the check, the signal from the transmitting antenna A2 is capacitively coupled to the receiving antenna A1 through continuous electrically conductive protective strips, while the signal from the transmitting antenna A3 is not capacitively coupled to the receiving antenna A1. The shortest distance between the transmitting antenna A2 and the receiving antenna Al is shorter than the longest length of the electrically conductive safety strips in the smallest tested

178 898 document. If the safety strips are not at any time during the check in the area of operation of the transmitting antenna A2 and the receiving antenna A1, the security strips will be in the area of operation of the transmitting antenna A3 and receiving antenna A1, so that further functions are performed analogously to the above-mentioned . There is then a signal on the receiving antenna A1 which, by means of rectifier 45 and selective amplifier 46, supplies a signal to microcontroller 47 which causes a truth classification by comparing the signal of selective amplifier 46 with the signal stored in microcontroller 47, e.g. in the form of a special threshold. If this threshold value is exceeded, then the microcontroller 47 classifies the test object as having continuous electrically conductive security fibers, i.e. in the case of German banknotes as a genuine banknote. If electrically conductive markings are provided in the safety strips which, due to their length, are not picked up by the transmitting antenna A2 and the receiving antenna A1, their identification is possible by arranging transmitting antennas B2.ii of the associated receiving antennas B1. their spacing is many times smaller than the distance between the transmitting antenna A2 and the receiving antenna A1. If, for example, the length of the electrically conductive mark located parallel to the document transport direction is 1.5 mm, then the distance between the transmitting antenna B2. I and the receiving antenna B1. I should be selected, for example, 1.3 mm in order to ensure a reliable capacitive coupling. On inspection, the security document to be examined moves at a predetermined speed in the area of operation of the inspection sensor of the inspection device according to the invention. By positioning the transmit antennas B2.i and receive antennas B1.i with an offset, tolerance compensation is caused by an orthogonal shift of the note in the document transport direction. The signals existing on the receiving antennas Bl. I are fed to the microcontroller 47 through rectifiers 48-50 and selective amplifiers 51-53. Depending on the condition and position of the protection fiber in the document, the signals of selective amplifiers 46, 51-53 fed to the microcontroller 47 differ in terms of frequency and amplitude. Thus, it is possible to classify the document by the microcontroller 47 by comparing the frequency and / or comparing the threshold value with the setpoints and stored in the microcontroller 47. These values are determined by manual input, programming and / or comparison with values that have already been determined as parameters at the same time. classified comparative document. The microcontroller 47 generates a machine-specific signal that indicates that the banknotes are being checked. This classification signal of the microcontroller 47 is coupled to the associated indicator elements and / or fed for further processing to a suitable machine interface.

Just as different currencies are distinguished by different security strips or fibers, counterfeits are also recognized if they have counterfeit security strips or fibers, or even just pieces of them. Due to the compact design of the entire test device, in particular due to the sensors and evaluation electronics which form a single unit, and the additional shielding measures, further possibilities for reducing the influence of disturbances, which in practice are of increasing importance, have been created. The arrangement of the checking devices in the machine is such that the normal transport of the banknotes is not disturbed by the checking sensors.

Figure 9 shows how an inspection device according to the invention is integrated, for example, in an existing machine. For this purpose, the checking sensor 54 consisting of the transmitting antennas A2, A3, B2. I and receiving antennas A1, Bl. I is integrated in the existing steering device 56. The checking sensor 54 is in this case arranged tangentially to the steering device 56 or tangentially offset to the roller. transport 55 so that it additionally takes over its guiding function in the area of the checking sensor 54. The banknote to be checked is thus brought without additional pressing means into the area of operation of the sensors. The inspection sensor 54 is arranged tangentially to the existing guide device 56 such that the security document to be examined, driven by the transport rollers 55, is fed to the inspection sensor 54 at a predetermined distance and from the

178,898 specified speed. By means of suitable fastening means on the guide device 56, in particular screws, the defined distance between the transport roller 55 and the guide device 56 or the checking sensor 54 is controlled. The parameterization of the threshold values and the classifying values is carried out by switches not shown in the drawings or by the corresponding software of the microcontroller 47. this allows the user to change the ranking quantities to check other currencies by simply toggling. In practice, in the absence of a signal or a non-banknote specific signal, the machine stops and the counterfeit or unusable banknote is removed.

By arranging the antenna array along the entire width of the document, the effect of paper quality, aging, moisture, etc. on the genuineness classification is reduced. This also includes the ability to classify, for example, counterfeit, genuine and highly worn banknotes. Such classification is carried out by appropriate evaluation of the amplitude and time waveforms of the signals from the selective amplifiers 46, 51-53 and appropriate parameterization of the threshold values by the evaluating microcontroller 47. The calibration of the microcontroller 47 is performed manually, under software control, or by checking special calibration documents for which are known to have been classified as true. In the latter method, the calibration document is checked by an inspection device according to the invention as described above. Instead of comparing the signals at the outputs of the selective amplifiers 46, 51 to 53 with the signals stored in the microcontroller 47, they are stored in the microcontroller 47 as reference quantities.

The further location of the checking sensor 54 is shown in patent application 195 18 229.4. According to this invention, the checking sensor 54 can be arranged, for example, at the end of a guiding device 56 which forms an arc of a circle, as shown in FIG. 10. The necessary pressure devices for guiding the test objects to the checking device with a defined distance and / or contact are also omitted. These possibilities can be used when the above-mentioned tangentially shown mounting of the checking sensor 54 cannot be realized in the arc-shaped region of the steering device 56. Since, according to the invention, pressure elements such as e.g. springs, pressure rollers, also the test object itself under load it is less mechanically by the checking device.

The method according to the invention is elucidated on the basis of specific implementation variants of the checking sensor and of the evaluation electronic system in a banknote counter. It should be noted, however, that the present invention is not limited to the details of the description of the embodiments, as variations and changes are included within the scope of the patent claims. For example, various designs of the electronic evaluation circuit oriented to the special operation of the selective amplifier are possible.

Claims (21)

1. The method of checking secured documents with the use of capacitive coupling between transmitters and receivers and energy transmission between transmitters and receivers by bridging the electromagnetic field by electrically conductive strips, tapes, document security fibers or flat-shaped security materials and signal reception by the attached electronic evaluation system, characterized by in the fact that in the area of the known optical sensors placed in the machine, which are spatially arranged according to the capacitive checking sensors in the machine and activate this checking sensor, many antennas located in one or more planes acting as transmitting or receiving sensors create checking fields, and the tested the object, depending on its geometric shape and / or its conductivity, moves in the field coupling these electromagnetic energy antennas, and moreover, many antennas are steered at least in different positions phase energy, and the transferred energy is sent to selective amplifiers (14), and in order to reduce the interference energy and to suppress the basic conductivity of the tested objects, e.g. banknotes, a phase comparator and a special filter for energy suppression are connected downstream of the selective amplifier (14) interfering and external as well as an evaluation unit which is positioned so that electrically conductive strips, tapes, tethers or flat-shaped safety materials can be classified, with the test object being forced during the inspection operation through the inspection field in an undefined position side. 2. The method according to p. A method as claimed in claim 1, characterized in that the evaluation electronic circuit consists essentially of an analog-to-digital converter and a driver or integrator (15), a trigger circuit (16), a driver, a single-stage flip-flop (17) and / or a gate (18), and based on the waveform. of the signal at the output of the selective amplifier (14), the exceedance of the limit amplitude (A) and / or the time (t _k ) specific for the checked currency is determined. 3. The method according to p. The method as claimed in claim 1 or 2, characterized in that the veracity classification is carried out by means of the electronic evaluation system, wherein a limiting amplitude (A) for the veracity of the currencies to be checked is set. 4. The method according to p. A method according to claim 1 or 2, characterized in that the electronic evaluation system carries out a classification of various banknotes and / or securities, the currency-specific time (t _k ) preferably being determined by means of a controller and sorting the test objects over time t _P . "T ^, t _{k + 1} .... t _n . 5. The method according to p. 4. The method of claim 4, characterized in that for currencies with different times (t _k ), an additional check is performed after the validation. 6. The method according to p. Method according to claim 1 or 2, characterized in that the electronic evaluation system, preferably one or more controllers, provides a machine-specific signal for arranging the individual sorted objects into special compartments or containers through a time comparison and / or a voltage comparison. 7. The method according to p. A method according to claim 1 or 2, characterized in that the antennas and / or electrodes transverse to the transport direction of the tested objects have such a surface length dimension that even with a certain lateral play of the tested objects and regardless of whether the tested object is facing upwards with its front side or its side back, in either case, the safety strip or fiber tactile covers the antenna and / or electrode at a certain distance. 8. The method according to p. A method as claimed in claim 1 or 2, characterized in that an additional check is carried out and the result is connected by means of an I-gate with the signal of the electronic evaluation system without the need to change the software of the machine in question. 178 898 9. Device for checking security documents with elements for capacitive coupling, with energy transmission between transmitters and receivers by bridging the electromagnetic field through electrically conductive strips, tapes, security fibers or flat-shaped security materials and with an electronic evaluation system, characterized by the fact that it has: known optical sensors existing in the machine for activating the capacitive checking sensors; checking fields, which are constituted by a plurality of sensors located in one or more planes acting as transmitting or receiving antennas, a selective amplifier (14) and an downstream phase comparator; special filters for suppressing interfering and external energy and an electronic evaluation system, essentially consisting of an analog-to-digital converter and a controller or an integrating circuit (15), a trigger circuit (16), a driver, a single-stable trigger (17) and possibly an I gate (18), and furthermore, the test object is positioned in an undefined lateral position on the rollers in defined contact with the sensors and with the displacement when inspected at a predetermined speed by means of holders and / or conveyor belts (10) arranged therein. 10. The device according to claim 1 9. A method according to claim 9, characterized in that the sensors acting as transmitting or receiving antennas are made as strip sensors (8; 9) arranged in one plane or in two planes facing each other and / or symmetrically mirrored. 11. The device according to claim 1 9. The sensor according to claim 9 or 10, characterized in that the strip sensors (8; 9) have cutouts and / or cuts and / or windows (7) or such elements are located in the immediate vicinity of the strip sensors (8; 9). 12. The device according to claim 1, 9. The method according to claim 9 or 10, characterized in that the sensors in the checking units are mirrored symmetrically with the checking zones, i.e. stripes, fibers and / or security strips of the objects to be checked, preferably banknotes, securities and packages. 13.A device for checking security documents with capacitive coupling elements, transmitting energy between transmitters and receivers by bridging the electromagnetic field through electrically conductive strips, tapes, security fibers or flat-shaped security materials and with an electronic evaluation system, characterized in that a plurality of transmitting antennas ( A2, A3, B2.1-B2.n) and a plurality of receiving antennas (Al, Bl.l-Bl.n) are placed to form the checking sensor (54) so that both the electrically conductive continuous strips and those which have a plurality of electrically conductive but insulated areas within one securing strip, the checking sensor (54) being tangentially parallel to the arc-shaped steering device (56) or tangentially offset to the transport roller (55), and two more controlled in counter-phase by n high frequency or high frequency transmitting antennas (A2, A3) are placed perpendicular to the direction of the length of the security strip and perpendicular to the direction of movement of the checked document, and one or more receiving antennas (Al) are parallel to the transmitting antennas (A2, A3) opposite them, and between them there are many transmitting antennas (B2.1-B2.n) parallel to transmitting antennas (A2, A3) and many receiving antennas (Bl.l-Bl.n) parallel to transmitting antennas (B2.1-B2.n) ), wherein adjacent transmitting antennas (B2.i, B2.i + 1) and associated receiving antennas (BI.i, BI i + 1) are positioned offset by a predetermined dimension, preferably by the spacing between the transmitting antenna (B2.i) and the assigned receive antenna (BI.i), and the smallest distance of the transmitting antenna (B2.i) from the assigned receiving antenna (B1. i) is smaller than the smallest distance between the transmitting antennas (A2, A3) and the receiving antenna (A1). 14. The device according to claim 1, The device of claim 13, characterized in that the plurality of transmit antennas (A2, A3, B2.1-B2.n) and the plurality of receive antennas (A1, Bl.I-Bl.n) extend across the width of the document feeding into the machine. The device according to claim 1, 13 or 14, characterized in that the transmitting antennas and receiving antennas (Al, Bl.l-Bl.n) are positioned parallel to each other and offset in one plane, so that they occur independently of the side and edge-independent of the two 178 898 parallel edges of the document, position neutral checking of the authenticity of documents. 16. The device according to claim 1, The receiving antennas (BI, 1-B1, n) and transmitting antennas (B2.1-B2.n) are spaced apart from each other in such a way that each checked security feature is spaced apart according to claim 13, as claimed in claim 13, characterized in that it includes at least one receive antenna (B1-B1.n) and an associated transmit antenna (B2.1-B2.n), irrespective of where it is positioned in the document. 17. The device according to claim 1, 14. The apparatus of claim 13, wherein the longest side of the transmitting antenna (B2.i) and the longest side of the associated receiving antenna (B1.i) correspond to the width of the guiding security strip marking. 18. The device according to claim 1, The method of claim 13, characterized in that the operable or program controlled switching and setting elements, in particular the microcontroller (47), are so arranged downstream of the rectifiers (45, 48-50) and the selective amplifiers (46, 51-53) that the outputs of the selective amplifiers (46) , 51-53) can be combined or logically summed. 19. The device according to claim 1 13, characterized in that the operable or program-controlled switching and setting elements, in particular the microcontroller (47), are so arranged downstream of the rectifiers (45, 48-50) and the selective amplifiers (46, 51-53) that switching between different types, and degrees of document consumption occurs without changing the sensor system. 20. The device according to claim 1 13. The device according to claim 13, characterized in that the shortest distance between two transmitting antennas (B2.i) arranged in series is greater than the smallest distance between two electrically conductive, insulated security fiber markings, and the switch means are further arranged such that the antenna (A3 ) is used either as a transmit antenna or as a receiving antenna depending on the feed of the document under test. 21. The device according to claim 1, 12. The switch according to claim 13, characterized in that the software and / or manual switch means are arranged such that one or more transmit antennas (B2.i) and the respective receive antennas (BI.i) can be active or inactive as desired.