CZ267097A3 - Process and apparatus for the control of protected documents - Google Patents

Abstract

The invention concerns a method and devices for checking security documents. According to this process which uses known capacitive coupling, electrical signals are transmitted by transmitting antennae via electrically conductive security features to receiving antennae and amplified. The amplitude responses and time characteristics of the electrical signals are then evaluated and compared with existing signal responses, by being converted into signal responses having easily comparable parameters. In order to enable the testing arrangement to be specifically selective, a selective amplifier is additionally coupled to the evaluation electronics. Currency-specific definition by means of the evaluation electronics according to the invention is attained in that, for a given currency, a time limit of the test signal amplitude can be determined by means of controllers, for example, this time limit differing from the duration of the amplitude response of all the other currencies.

Description

Technical field

BACKGROUND OF THE INVENTION The present invention relates to a method of controlling protected documents using a capacitive coupling between a transmitter and a receiver, and transmitting power between a transmitter and a receiver by bridging the electromagnetic field with electrically conductive protective strips, tapes or fibers. The invention also relates to a device for checking protected documents with capacitive coupling elements, transmitting energy between a transmitter and a receiver by bridging the electromagnetic field with electrically conductive protective strips, tapes or fibers or by providing a protective area with the aid of evaluation electronics.

BACKGROUND OF THE INVENTION

A number of methods, devices, methods and control systems are known for verifying the authenticity of protected documents, for determining their applicability, for determining their position in processing facilities, as well as for determining their type and counting. For example, DE-PS 1223594 discloses an apparatus for capacitively sensing record carriers in which sensing capacitors consist of sensing electrodes which are arranged on both sides of the path of the record carriers. This device does not allow reliable detection of inserted, pressed-in or deposited electrically conductive strips, tapes or other elements.

DE-PS 1774290 discloses a measuring device for automatically evaluating a feature of a banknote in a banknote authentication device based on a capacitive coupling of lattice-arranged electrodes. This known measuring device

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Even at the currently required high banknote processing speeds, it is not possible to precisely determine the characteristic in question, and even in a slow inspection, only the presence of such a feature is detected. Thus, in the current state of counterfeiting banknotes using electrically conductive security features, the device does not meet current requirements.

DE-OS 2619457 describes the measurement of the magnetic properties of a security strip on a banknote.

DE-PS 2834287 discloses the verification of the authenticity of ferromagnetic protective fibers in a security document by means of a magnetic field. These inspection methods are too slow and require precise positioning of the object to be inspected, possibly with a protective strip.

DE-PS 2760165 describes a technically sophisticated inspection device in which a second inspection area is tested for the authenticity of banknotes by measuring the thickness differences and the fluororescence properties. Checking only these characteristics no longer corresponds to the state of the counterfeits in circulation. Counterfeit banknotes with a watermark and flouroscopic paper or paint can no longer be recognized by this device.

DE-OS 3236373 and 3236374 also disclose, inter alia, readheads in document processing machines which, with protective elements on protected documents, form an electrical capacitor and by introducing ferroelectrics between the capacitor electrodes of the reader, a defined change in the capacity value is defined. These read heads are not suitable for fast-working document processing equipment and for checking the European currency currently in circulation.

DE 2912712 describes the demonstration electrically

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Even conductive protective fibers by tuning oscillators and resonant circuits, which, due to low reliability of evaluation and high technical demands and complex design, did not succeed.

US 5,308,992 discloses a measuring device that includes optical and capacitive sensors and requires precise positioning of the object to be inspected. In order to increase the reliability of the measurements and to allow different objects to be detected, for example different currencies, the additional use of magnetic sensors is proposed, which further complicates and increases the cost of the construction of the measuring device. The capacitive sensor only indicates the presence of an electrically conductive protective thread after the banknotes have been sorted.

DE 4103832 furthermore discloses a control device in which capacitive and / or electro-optical and / or microwave sensors operating in the millimeter wave region are arranged along the control path for measurement. The measurement also includes a check of the dielectric properties of the banknotes.

DE 43 25 027 describes a method and an apparatus for checking the authenticity of banknotes, whereby the field strength variations resulting from the bridging of the high-frequency field by metal protective strips are evaluated. Due to its low sensitivity and low interference suppression, the use of this device in banknote counting devices is limited to slow-running banknote counting devices. In addition, surface conductive and damp inspected objects are misunderstood as true. It is not possible to discern the breakage of the metal strips in the genuine banknotes, so the whole device is unnecessarily stopped. Due to the low sensitivity, the distance between the electrodes and the metal banknote of the banknote must be very small, preventing this control device from being used in fast-working banknote processing machines.

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The inclusion of several such sensors is possible only at a considerable distance from one another so that the sensors do not interfere with one another.

WO 94/22114 discloses an apparatus for recognizing metal conductive protective strips. Also in this case, surface-conductive and damp inspected objects are also recognized as true because the measurement is carried out on the basis of the electrical charge of the sensor electrodes. It is not possible to classify protective strips of different sizes.

EP 0204 574 describes a method for detecting a magnetic pattern by electromagnetic induction. Since already available copiers can be equipped with a magnetically conductive ink, the reliability of this inspection method at the current level of counterfeits is greatly limited.

The disadvantages of these known control methods and devices are, first of all, their high technical demands and their lack of reliability in the detection of counterfeits during the rapid passage of banknotes in banknote handling machines. A disadvantage of the known capacitance measuring devices is that a sufficiently small capacitance is achieved only in the low frequency range used from 10 to 220 kHz and at very short distances between the electrodes and the metal fibers. Moreover, in the said frequency range, there is a very large effect of the dielectric change, which means that a material with a high dielectric constant causes an increase in capacitance and thus a decrease in capacitance between the antennas. This leads to the fact that, for example, a damp counterfeit would be found as a genuine banknote. In practice, these devices, in particular for machine authenticity testing, have not yet proved their worth.

EP 589 195 A2 discloses a method in which, based on a signal to verify the authenticity of objects, obtained by sensing a sensing area with high-permeability magnetic elements,

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I obtains an assignment code by means of a device with an excitation coil and a sensing coil and the authenticity is confirmed by the match of the proof signal and this assignment code. The method described is applicable only to magnetic or magnetic elements bearing plastic cards, some documents and only some non-European banknotes.

Further control methods are described in EP 204 574 A2, 553 402A1 and 560 023 A1 according to which the geometric and / or physical properties of the objects to be inspected are classified by the comparative method. The methods are always applicable to only one type of object to be inspected, are very costly and, in practice, have not succeeded as the only way of checking authenticity in banknote handling machines with the required high working speed.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the existing shortcomings of known control devices and methods and to find a method that will reliably recognize a characteristic security feature that will be applicable to multiple kinds of banknotes and currencies. The method and apparatus of the present invention are intended to enable the objects to be distinguished from each other, to be technically undemanding, and to be able to equip them with banknote processing machines which operate with rapid passage of the objects to be inspected. An electrically conductive security strip or strip or a flat area in banknotes and securities is used as a characteristic control feature. Another object of the invention is to construct an apparatus for carrying out the method according to the invention in such a way that this can be upstream, i.e., that the authenticity of the banknotes can be checked before sorting by type and currency.

It is a further object of the present invention to provide an apparatus for carrying out the method of the present invention which allows to check the authenticity of protected documents that include a strip or fiber electrically conductive strip as a security element, both when the strip is electrically conductive. if it consists of electrically conductive but mutually insulated sections.

An example of such a protected document is the current US banknotes whose protective thread is comprised of electrically conductive but isolated sections from each other. For current practice, it is necessary to incorporate in banknote handling machines such control systems that recognize as such not only high quality counterfeits, but also genuine documents of lower quality, as these occur very frequently in practice and lead to error messages that interferes with the operation of banknote and protected document processing equipment in general.

SUMMARY OF THE INVENTION

The problem is solved and the deficiencies of known analogous methods are largely eliminated by the method of controlling protected documents using capacitive coupling between the transmitter and receiver and transmitting energy between the transmitter and receiver by bridging the electromagnetic field with electrically conductive strips, tapes or fibers or according to the invention, characterized in that in the field of optical sensors and / or magnetic and / or format sensors known per se, the spatial correspondence of the capacitive scanning system in the document processing system is activated by the capacitive scanning system. sensor array, one or more control fields are formed in one or more planes with antennas acting as transmitters or receivers and e transmits electromagnetic energy by antennas depending on its geometry and / or conductivity, whereby the antennas are excited with different phases and the transmitted energy is fed to a connected selective amplifier to which it is connected to suppress the interfering energies and the basic conductivity of the objects a phase comparison circuit, special filters for suppressing disturbing and extraneous energies, and an evaluation unit that are arranged to allow the classification of electrically conductive protective strips, tape, fibers, or surface protection zones, with the object being controlled guided by these inspection points field in undefined side position.

It is preferred that the evaluation electronics, consisting essentially of a digital / analog converter and a controller or an integrated circuit, a trigger circuit, a controller, a monostable flip-flop, and / or a product gate, determine from the waveform at the selective amplifier output currency of a specific time interval.

The evaluation of the authenticity is carried out by means of the evaluation electronics preferably by determining the limit amplitude for the authenticity of the currency to be checked.

The classification of the various banknotes and / or securities is carried out by means of the evaluation electronics such that, preferably by means of a controller, a time-specific currency is determined and the objects to be inspected are sorted according to time intervals.

For currencies with the same time intervals, an additional authenticity check is preferably performed.

A special evaluation unit, preferably one or more controllers, provides a signal to the device for storing individual classified objects in special compartments or column containers based on a comparison of time intervals and / or voltages.

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The antennas and / or electrodes have transverse dimensions to the direction of transport of the objects to be inspected such that the protective strip or the fiber, even with a defined lateral clearance of the objects to be inspected and regardless of whether the object to be inspected, the antennas and / or electrodes it touches pass at a defined distance.

Furthermore, it is advantageous if an additional check is performed and the result thereof is mixed with the signal from the evaluation electronics by means of a product gate without having to change the software of the protected document processing device in question.

The invention also relates to a device for checking protected documents by means of capacitive coupling elements, energy transfer between a transmitter and a receiver by bridging an electromagnetic field by electrically conductive protective strips, tapes or fibers or by means of protected areas using evaluation electronics according to the invention. that the device comprises known in the document processing apparatus arranged optical sensors for the activation of capacitive control sensors, test fields which are formed in one or more planes by arranged sensors acting as transmit or receive antennas, a selective amplifier and a circuit for it connected to it Phase comparison, special filters for suppression of interfering and foreign energy and evaluation unit, consisting essentially of an analog / digital converter and a controller or an integrated circuit , the trigger circuit, the controller, the monostable flip-flop and / or the product gate, wherein the object to be inspected is arranged in an undefined lateral position such that it is guided around the control sensors by brushes and / or pressure elements and / or conveyor belts arranged there. , rollers, clamps and the like at a defined speed and in contactless contact.

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The sensors, acting as transmit or receive antennas, are arranged as strip sensors in one plane or opposite and / or mirror-symmetrical in two planes.

The band sensors are preferably provided with cut-outs or openings or windows, or the cut-outs or openings or windows are provided in the immediate vicinity of the band sensors.

The sensors of the control unit are preferably arranged mirror-symmetrically to the control zones and / or the security strips, security threads and / or security strips of the objects to be inspected, in particular banknotes, securities and packages.

The invention also relates to a device for the control of protected documents with capacitive coupling elements, energy transfer between a transmitter and a receiver by bridging an electromagnetic field with electrically conductive protective strips, tapes or fibers or surface protection areas and evaluation electronics according to the invention. The transducer antennas and the receiving antennas forming the control sensor together are arranged in such a way that both the electrically conductive protective strips and the protective strips consisting of a plurality of electrically conductive but insulated sections can be inspected, the control sensor being arranged tangentially with a parallel displacement relative to the arc guiding device or tangentially with a parallel displacement relative to the transport roller and two counter-frequency low or high frequency driven transmit antennas j are arranged perpendicular to the larger dimension of the security strip and perpendicular to the direction of movement of the document to be inspected, one or more receiving antennas are disposed parallel to the transmitting antennas, and multiple transmitting antennas are arranged parallel to the transmitting antennas, and multiple receive antennas the adjacent transmitting antennas and respective receiving antennas are displaced by a defined distance, preferably a distance between the transmitting antenna and the respective receiving antenna, and the smallest distance from the transmitting antenna to the respective receiving antenna is less than the smallest distance between one of the transmitting antennas and receiving antenna.

The transmitting antennas and the receiving antennas are preferably arranged over the entire width of document retrieval in the document processing device.

The transmitting antennas and the receiving antennas are arranged side-by-side, parallel and offset, preferably in a plane such that the authenticity of the documents is performed independently of the side and the edge of the document between the two edges of the document.

Advantageously, the receiving antennas and the transmitting antennas disposed parallel to and / or in a line transverse to the transport direction are arranged such that each of the security elements to be inspected, independently of their arrangement on the document, travels at least one receiving antenna and the respective transmitting antenna.

Preferably, the longer side of the transmitting antenna and the longer side of the respective receiving antenna correspond to the width of the conductive security element of the security strip.

The switching or adjusting elements controlled by the operator or software, in particular the microprocessor, the rectifier and the selective amplifier, are preferably arranged such that the output signals of the selective amplifiers can be combined or logically combined.

The operating or software-controlled switching and adjusting elements, in particular the microprocessor, the rectifier and the selective amplifier, are preferably arranged in such a way that switching between the different types and types of documents and their degree of wear is possible without changing the sensor arrangement.

Preferably, the smallest distance between two transmit antennas arranged in a row is greater than the smallest distance between two electrically conductive, insulated guard thread elements and the switch elements are arranged such that the antenna is usable either as a transmit or receive antenna depending on the feed of the document to be inspected.

The software and / or manually controlled switching elements are preferably arranged such that one or more transmitting antennas and respective receiving antennas can optionally be activated or deactivated.

Using the known capacitive coupling, the method of controlling protected documents according to the invention assumes that the electrical signals from the transmitting antennas are transmitted to the receiving antennas via the electrically conductive protective elements and subsequently amplified, then evaluated according to the amplitude and time course and compared to existing waveforms. signal by converting it into waveforms containing easily comparable parameters. For carrying out this method, the steps of which will be described in more detail below, a control device is provided for banknotes, documents, securities and the like, which are provided with security strips or fibers or flat security elements using a capacitive coupling, which can be used, for example in a banknote processing machine, in particular in a banknote counting machine. A set of sensors is arranged on the housing of the sensor in the area of optical and / or magnetic and / or format sensors. The device guides banknotes and / or securities around the control device. The sensor assembly comprises multiple antennas and / or electrodes. The antennas and / or electrodes have a surface area in the direction transverse to the direction of transport of the objects to be inspected such that, even at a defined lateral clearance and irrespective of whether the object to be inspected faces upwards with its front or rear side, in any case, sufficiently traverse the antennas and / or electrodes. The control unit antennas and / or electrodes correspond to known sliding guides, thrust rollers and / or conveyor belts, so that the objects to be inspected can be guided at a defined distance around the antennas and / or pressed against the electrodes when they pass rapidly. By arranging the control unit according to the invention in the field of optical and / or magnetic and / or format sensors, which are usually used to recognize geometry, position, color or the like, it is simultaneously ensured that the control unit is activated.

One or more of the antennas and / or electrodes are supplied with high and / or low frequency energy, and one or more of the antennas and / or electrodes again sense a portion of the radiated energy through the protective strip. Thus, the voltage at one or more of the receiving antennas and / or electrodes varies.

In order to achieve comparable control results, for example in terms of authenticity, usability of documents or currency of banknotes, it is necessary to ensure constant passage conditions for the objects being compared, for example the speed of the passage. The antennas and / or electrodes supply voltage to the evaluation electronics. The evaluation electronics generate well-comparable signals based on this voltage. Special filters and / or phase comparison circuits may be used to suppress the influence of interfering and extraneous energies as well as the effect of the basic conductivity of the inspected objects on the measurement result.

The output pulse of the evaluation electronics is independent of the speed of the object. In order to achieve specific selectivity of the monitoring device, it is additional to the evaluation electronics

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I connected a selective amplifier. The selective amplifier converts the voltage supplied from the sensing unit to an easily comparable voltage which depends on the amplitude of the incoming voltage. When defining the evaluation electronics by category (electrically conductive protective strips or protective fibers or any conductive protective elements), additionally, the amplitudes are determined whose course is so close to the amplitude of the control signal that the authenticity can be determined by the difference between the defined limit amplitude and the permissible the largest amplitude amplitude of all the objects inspected. This means that even newly occurring counterfeits which give a signal that would otherwise be interpreted as a signal of their authenticity are recognized as counterfeit by the evaluation electronics according to the invention.

The recognition of different currencies, for example all currencies of individual states with similar protective strips, is achieved by the evaluation electronics according to the invention such that for each currency, for example, a driver can determine an amplitude time limit which differs from that of all other currencies.

For currencies with the same amplitude of the control signal amplitude, an additional check is performed, for example by determining and / or color resolution and / or according to magnetic properties and / or format. The distinguishing signals supplied, for example, by light barriers, are associated with a signal from the evaluation electronics according to the invention, and a signal is generated from the resulting signal for controlling the entire device.

One variation of the method according to the invention is that in order to check the protected documents, one or more pairs of transmit antennas are excited with phase shift. Due to the capacitive coupling between each of the transmitting antennas, the electrically conductive protective strip element and the receiving antenna opposite to the transmitting antenna,

I input an amplifier signal that tells the authenticity of the object being checked. There is no signal bonding to the receiving antenna from another transmitting antenna which is excited with phase shift relative to the first transmitting antenna because there is no electrically conductive guard strip in the area of application. Thus, in this embodiment, it is already possible to inspect the electrically conductive protective strip. Offset with respect to this pair of antennas, further pairs of transmitting and receiving antennas are provided, which are dimensioned and spaced apart by electrically conductive elements of the security strip. When the object to be inspected is transported at a defined distance from the control sensor, signals with characteristic amplitudes and time intervals are obtained. These evaluable signals are then fed from the receiving antennas to the evaluation electronics. Thus, a check is carried out which is capable of recognizing and evaluating accordingly a plurality of electrically conductive protective elements which are insulated from each other. It is immaterial whether the insulation between the electrically conductive security elements is deliberate, as is the case with US banknotes, for example, or whether the formation of insulated spots has been caused, for example, by an interruption of the originally produced continuous electrically conductive security strip. The number of these interrupts can be compared with the stored values in the microprocessor. The use of multiple pairs of transmit and receive antennas and the associated evaluation electronics makes it possible to obtain a reliable statement of the authenticity of the document to be checked, since the inspection device operates reliably despite possible lateral displacements when the inspected document is fed to the inspection device. If the transmitting or receiving antennas according to the invention are arranged over the entire working width of the document processing device, authentication is possible independently of the position of the protected document. Consequently, it does not matter whether the document is fed upwards by the front or back side and / or with the left or right side of the security strip and / or laterally displaced transversely to the transport direction. This makes it possible to check documents that may differ from each other both in size and arrangement of the security strip in the transport direction. Thanks to different types of security strips, it is not only possible to classify the authenticity of documents, but also to allow special assignment of different documents, such as the classification of different currencies.

A further monitoring sensor may be provided upstream and / or downstream of the monitoring sensor according to the invention. In this case, the output signal of the control sensor is associated with the output signal of the control sensor according to the invention, so that a double control is achieved without having to change the software of the document processing device concerned, for example when retrofitted with the control device according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS The invention is further elucidated with reference to the accompanying drawings, in which: FIG.

FIG. 1 shows a block diagram of an evaluation circuit,

- Fig. 2 shows the curves taken as the banknote passes at different speeds,

- in Figure 3, the sensing curves specific to different currencies,

- the scanned curves of several banknotes and counterfeit in FIG.

FIG. 5 is a block diagram of an evaluation circuit in double inspection;

- Fig. 7 control sensors,

FIG. 8 is a block diagram of a control device,

FIG. 9 shows the arrangement of inspection sensors in a document processing machine, and

FIG. 10 shows another possibility of arranging the control sensors in the device.

DETAILED DESCRIPTION OF THE INVENTION

The method described below in more detail on the basis of various devices and systems consists essentially in performing the following steps: capacitively transmitting electrical signals from transmit antennas via electrically conductive protected materials to receiving antennas, amplifying and converting received signals of different amplitudes and timing into easily comparable signals; comparing these signals with pre-existing waveforms to indicate and evaluate the authenticity of the documents to be checked in an appropriate form. Banknotes or securities are transported through the control device by a transport device that is coupled to the control device. The control sensors are activated by light barriers accordingly.

The transmitting antenna is supplied with high-frequency energy, the frequency of which in the present embodiment is 6 MHz. As the protective strip or fiber passes through the control field, some of the radiated energy is again sensed by the receiving antenna. The RF voltage on the receiving antenna is changing. The reason is, as is known, a capacitive coupling between the transmitting and receiving antenna due to the electrical conductivity of the protective strip or fibers. The high-frequency conductivity varies between currencies. In order to obtain a currency-specific response using the evaluation circuit, they are needed

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Even constant conditions of the passage of all object-controlled objects.

The control unit with its control sensors is operatively interconnected with shielded cables to the evaluation electronics, which essentially consists of an analog / digital converter and a controller or integration circuit 15, a trigger circuit 16, a monostable flip-flop 17 and / or a product gate 18. is shown in block 1 in FIG.

The evaluation circuit further comprises a radio frequency transmitter 12 and a radio receiver 13 which senses the voltage at the receiving antenna 9, which in the selective amplifier 14 amplifies into a signal that is specific to the currency and / or authenticity of the document. The evaluation circuit further comprises an integration circuit 15 and a trigger circuit 16 which, in addition to the signals present, senses the signals for activating the evaluation circuit from the light barriers 20. and outputs them via a monostable flip-flop 17 as time coordinated pulses have been found genuine. As can be seen from the curves a and b in Fig. 4, which describe the passage of banknotes, no output signals are generated when passing the counterfeit 26 that are comparable to the output signals of the banknotes found to be genuine.

The high mutual distance of the useful signal from the interfering signals is ensured by the defined shielding of the control sensors and the evaluation circuit against the electric and electromagnetic fields, and also by the arrangement of the control sensors in the area of the light curtains. In conjunction with the controlled passage of the controlled objects, which is secured by the conveyor belts, and the defined rate of passage of the banknotes, the selectivity of the control device against the currency is ensured. A further advantage of the process according to the invention is that the moisture content and / or the degree of

I dirty objects and / or banknotes and / or securities.

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FIG. 6 is a cross-sectional view of a control device used in the banknote processing machine, in particular a banknote counting machine, by the method of the invention. On the cover 1 there is arranged a support frame 2, on whose horizontal arm 3 there are arranged control sensors, which are located on the non-conductive material 6 of the horizontal arm 3 in the region of the light barriers 4, 5. These recesses and / or openings 2 may be omitted when a transparent carrier material 6 is used.

The control sensors consist of a plurality of band sensors 8, 9, in this case two, i.e. a band sensor 2 representing the transmitting antenna and a band sensor 9 representing the receiving antenna. These strip sensors 8, 9 have a surface area in the direction transverse to the transport direction of the banknotes 11 such that, even with a defined lateral clearance of the banknotes 11 and irrespective of whether the banknote 11 passes through the control device with the front or rear facing upwards or the thread on the banknote 11 is still sufficiently passed over by the band sensors 8, 9, i.e. the protective strip or the thread on the banknote 11 is always guided under these band sensors 8, 9 through the control device. 3 conveyor belts run parallel to this horizontal arm 10, at such a distance from the band sensors 8, 9 that the banknotes 11 are pressed against the band sensors 8, 9 during their rapid passage.

Between the conveyor belts 10, light barriers 4, 5 are arranged perpendicular to the direction of passage of the banknotes 11.

The evaluation electronics are also arranged in a shielded one

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Also in the area of the banknote processing device 11, in this exemplary embodiment preferably in the housing area, where, for example, a device for adjusting to the thickness of the paper is arranged.

The high mutual distance of the useful signal from the interfering signals is ensured by the defined shielding of the control sensors and the evaluation circuit against the electric and electromagnetic fields and also by the arrangement of the control sensors in the area of the light curtains. In conjunction with the controlled passage of the inspected objects, which is secured by the conveyor belts 10, and the defined rate of passage of the banknotes 11, the selectivity of the control device against the currency is ensured. A further advantage of the method according to the invention is that the moisture content and / or the degree of soiling of the objects and / or the banknotes 11 and / or the securities are no longer a prominent factor, for example.

In the direction of transport of the banknotes 11, other, not shown control sensors, not shown in this example, may be upstream and / or connected, for example for magnetic control, as indicated in the block diagram of FIG. 5.

The output signal of these additional control sensors is in this case combined with the control sensor signal according to the invention, so that this double check does not have to modify the software of the respective banknote processing machine 11, for example when it is equipped with the control device according to the invention.

The evaluation electronics or circuit, which is connected to the control sensors and photocells, generates, as shown in Figs. 2 and 3, a DC voltage that depends on the amplitude of the received RF voltage. In Figures 2 and 3, the transmitted signals are indicated by curves.

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FIG. 2 shows the sensed curves as the banknote 11 passes at different speeds. Curve a shows the transmitted signal and curve b the output signal of the evaluation electronics. The rate v1 corresponds to the passage of 500 banknotes 11 per minute and the rate v2 corresponds to the passage of 1800 banknotes 11 per minute. In addition, curve b illustrates how the signal from the control sensors is associated with the signal for detecting banknotes 11 from the light barriers 4, 5 and j, thus producing a device-specific output pulse. As can be seen from the comparison of the curves b in FIG. 2, this output pulse is independent of the rate of passage of the banknotes 11.

Fig. 3 shows currency-specific sensing curves as banknotes of different currencies pass through. Curve a again shows the transmitted signal from the control sensors, while curve b evaluated the signal from the selective amplifier, which is additionally connected to the evaluation electronics, in order to achieve selectivity to different currencies without the need for additional sensors. The DE symbol in Fig. 3 denotes German currency, CH Swiss currency, EG Egyptian currency and CN Chinese Yuan since 1990 series.

In the case of banknotes of different currencies, the variation in the amplitude of the received RF energy is clearly evident, which is conditioned by the different types of security strips and is thus detectable by the evaluation electronics. If it is necessary to process signals depending on the currency, the signal generated by the evaluation electronics can additionally be used to distinguish currencies, for example by means of a controller. As different currencies can be distinguished from each other according to different security strips or fibers, counterfeits are also recognizable as long as they are provided with imitated security strips or fibers or only parts thereof. Fig. 4 shows the scanned curves of eleven banknotes in a banknote counting machine. Banknotes 21, 22, 23, 24, 25 and 27, 28, 29, 30, 31 were recognized as genuine banknotes. A fake 26 was intentionally included in this series for comparison.

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Due to the absence of a security strip or a simulated security strip, the control sensors did not generate any signal. In practice, in the absence of a signal or the occurrence of a signal not corresponding to the banknote, the banknote handling device is stopped and the counterfeit or unusable banknote is removed or sorted by machine.

If the control unit is additionally coupled to other control sensors, this machine-specific output pulse indicates the recognition of the security thread or thread and is logically associated with the output signal of the additional banknote processing device. If one of these authenticity signals is missing, the unit will stop and the operator may remove the faulty or false banknote.

A further possibility of use arises from the evaluation of the selective amplifier signals, as shown in FIG. 3, when the evaluation electronics are appropriately defined. If the larger amplitude banknote processing machines, which are also used for sorting different currencies, exceed the limit amplitude A for all As shown in FIG. 3, these banknotes are recognized at a rate v2 as banknotes provided with a genuine security thread or thread to which the control sensors respond. Each currency is assigned a specific time interval tk. In order to distinguish individual currencies from one another, the time intervals tk = tl ... t4 to tn must be defined as tf according to the currency. For example, the tf value of the German currency must be chosen greater than t2 Swiss francs, or the tf value of the Swiss francs must be chosen greater than t3 of the Egyptian currency. Since the tf value of the German currency must optionally be chosen to be equal to the tf value of the currencies not shown in FIG. 3, a further check of the currency-specific features is required in the banknote processing machine, for example known color and / or format and / or magnetic properties. Individual categorized in this way

Even currencies are stored in a well-known manner in compartments or column stacks.

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In particular, banknote and document processing devices are provided with control sensors 54 as shown in FIG. . The banknotes, when inspected through the entire banknote processing device, such as a banknote counting device, reach the transport device such that the security thread or thread contained in the banknote is oriented approximately parallel to the transport direction, e.g. the German banknote lies approximately transverse to the transport direction. The transmitting antennas A2, A3 and the receiving antenna A1 are aligned with each other. Against this offset sets of transmitting antennas B2. i (i = 1..n) and a plurality of receiving antennas B1. i are always arranged as pairs of antennas. These pairs are offset from each other in order to suppress the binding of the signal from the transmitting antenna B1 to an adjacent but not relevant receiving antenna B1. k (k = 1..n, i <> k). Adjacent transmitting antennas (B2.i, B2.i + 1) and respective receiving antennas (Bl.i, B1, i + 1) are aligned with each other with a defined offset, preferably equal to the distance between the transmitting antenna (B2.i). and an appropriate receiving antenna (B1.1). In order to reduce the interference, pairs of antennas that are offset diagonally from one another are preferably arranged between the transmitting antennas A2, A3 and the receiving antenna A1.

FIG. 8 is a block diagram of a control device according to the invention for controlling the control sensors of FIG. 7. When a document is loaded into a device containing the control device according to the invention, the control device is activated by light barriers or other position sensors. First Generator 41

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Also, the high frequency oscillations drive the transmitting antenna A2 and through the first phase shift circuit 42 also the transmitting antenna A3. Phase-shifted excitation avoids disturbance by foreign energies and also recognizes counterfeits that have no differences in electrical conductivity. This also applies to banknotes whose properties have changed, for example due to aging and / or mechanical damage and / or moisture. A plurality of transmit antennas B2, i (i = 1.n) are simultaneously excited by the second high frequency oscillator 43 and the second phase shift circuit 44. Transmitting antennas B2.i that do not lie transverse to the direction of transport in the line are driven by phase shift bridges to suppress interference with foreign energies and to avoid capacitive coupling between the transmit antenna B2.i and the unsuitable receiving antenna B1.k (k = l. n, i <> k). The frequency of the signals from the two high-frequency oscillators 41, 43 is selected such that one of the frequencies is not a multiple of the other or a multiple of the difference between these frequencies in order to prevent false signals from being received on the receiving antennas A1, B1.

In the inspection, the signal from the transmitting antenna A2 is capacitively coupled to the receiving antenna A1 through a pass-through electrically conductive security strip in the banknote, while the transmitting antenna signal A3 is not capacitively transmitted to the receiving antenna A1. The smallest distance between the transmitting antenna A2 and the receiving antenna A1 is less than the largest length of the electrically conductive security strip in the smallest document inspected. If, at any time during the inspection, the security strip is not in the area of operation of the transmitting antenna A2 and the receiving antenna A1, then the security strip is in the area of operation of the transmitting antenna A3 and the receiving antenna A1, so that other functions are analogous to the above. At the receiving antenna A1 there is a signal which is routed through the rectifier 45 and the selective amplifier 46 to the microprocessor 47, which compares the signal from the selective amplifier 46 to the signal stored in the microprocessor 47, for example with a special threshold

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Even by value, it will classify the authenticity of the document being checked. If the threshold is exceeded, the object to be inspected by the microprocessor 47 is evaluated as having an electrically conductive protective filament, i.e. in the case of German banknotes, as an authentic banknote. If there are electrically conductive markings in the security strip which, due to their dimensions, cannot be captured by the transmitting antenna A2 and the receiving antenna A1, they are enabled by the array of transmitting antennas B2, i and the corresponding receiving antennas B1. according to the invention, since their mutual distances are many times smaller than the distance between the transmitting antenna A2 and the receiving antenna A1. For example, if the dimension of the electrically conductive mark parallel to the document transport direction is 1.5 mm, the distance between the transmitting antenna B2 is required. 1 and the receiving antenna B1.1 can be chosen, for example, 1.3 mm in order to ensure a reliable coupling. The protected document to be inspected is transported at a defined speed through the area of application of the control sensors in the control device according to the invention. The offset arrangement of the transmit antennas B2, i and the receive antennas B1.i defines the compensation of the tolerances when the document is moved in a direction perpendicular to the document transport direction. The signals received by the receiving antennas B1.1 are fed to the microprocessor 47 via rectifiers 48, 49, 50 and selective amplifiers 51, 52, 53. The signals coming to the microprocessor 47 from the selective amplifiers 46, 51, 52, 53 vary in their frequency and amplitude, depending on the nature and position of the security thread in the document. As a result, microprocessor 4 7 is a possible classification of the document, which is done by comparing frequencies and / or threshold values with predetermined values that are stored in microprocessor 47. These values are entered manually, programmatically and / or by values determined on the basis of a classified comparative document. The microprocessor 47 generates a device-specific signal to indicate the authenticity of the banknote being checked. This classification signal from the microprocessor 47 is fed to the respective display elements and / or for further processing

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Also into the appropriate interface of the banknote handling machine. Just as different currencies can be recognized on the basis of different security threads or threads, counterfeits can also be recognized if they contain imitated security threads or even sections of these security threads. The compact design of the entire monitoring device, in particular the single-unit sensor and the evaluation electronics, together with the additional shielding, allow interference suppression, which is of increasing importance in practice. The design of the banknote processing machine can be designed in such a way that the control sensors do not interfere with the normal banknote transport.

FIG. 9 shows an example of incorporating a control device according to the invention into an existing banknote processing machine. A control sensor 54, which consists of transmit antennas A2, A3, B2. The control sensor 54 is arranged tangentially to the guide device 56, respectively tangentially and displaced relative to the transport roller 55, so that it additionally assumes the function of a bank note guide in this area. Thus, the inspected banknote enters the area of the inspector 54 without the need for additional pressure means. The control sensor 54 is arranged tangential to the existing guide 56 so that the protected document to be inspected, which is transported by the transport rollers 55, is guided around the control sensor 54 at a defined speed at a defined distance. By means of suitable fastening means on the guide device 56, in particular the set screws, a defined distance between the transport roller 55 and the guide device 56 or the control sensor 54 is adjustable. The parameterization of the thresholds and the classification quantities is carried out by means of switches (not shown) in the drawings, or by means of the corresponding software in the microprocessor 47. Thus, the user can change these classification quantities simply by switching over, for example to check other currencies. In practice, the process takes place in the absence of a signal

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Even with a non-banknote signal, the banknote processing machine stops and the counterfeit or unusable banknote is removed.

By dimensioning the array of antennas across the width of the document, affecting the classification of authenticity by factors such as paper quality, age, humidity, and the like is reduced. This includes the possibility of classifying, for example, counterfeit, genuine and high-wear banknotes. This classification is performed by the evaluating microprocessor 47 based on a corresponding evaluation of the amplitudes and time courses of the signals from the selective amplifiers 46, 51, 52, 53 and the respective threshold parameter parameters. The calibration of the microprocessor 47 is carried out manually, controlled by software or by checking special calibration documents, the classification of which is known. In the latter case, the calibration document is checked with the inspection device according to the invention as described above. Instead of comparing the signals at the outputs of the selective amplifiers 46, 51, 52, 53 with the existing signals in the microprocessor 47, these signals are stored in the microprocessor 47 as reference values.

Another possible location for the installation of the control sensor 54 is shown in German Patent Application No. 195 18 229.4. According to the present invention, the inspection sensor 54 may be incorporated, for example, at the end of the arch guide 56 as shown in FIG. 10. Also, there are no additional pressure devices for guiding the inspected objects at a defined distance from and / or in contact with the test device. testing equipment.

This solution is used when the above-described tangentially offset installation of the control sensor 54 in the arc region of the guide device 56 cannot be realized. Since pressure means such as springs or pressure rollers are omitted according to the invention, the test object itself is also a test item.

Even less stressed by the equipment.

The method according to the invention has been described on the basis of specific exemplary embodiments of control sensors and evaluation electronics in a banknote counting device. It should be noted, however, that the present invention is not limited to the details set forth in the description of the exemplary embodiments, as many modifications and variations are within the scope of the appended claims. For example, various evaluation electronics are possible which are related to the special function of the selective amplifier.

Represented by:

Ing.J.Chlustina

22.08.97 (i, 6/7 // 'PV & - μ - 97

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Claims (21)

PATENT CLAIMS 1. A method of controlling protected documents using a capacitive coupling between a transmitter and a receiver and transmitting power between a transmitter and a receiver by bridging an electromagnetic field by electrically conductive protective strips, tapes or fibers or by means of shielded areas by means of connected evaluation electronics. The optical sensors and / or magnetic and / or format sensors known per se, which in the document processing device spatially correspond to and activate the capacitive scanning sensor system, have one or more planar antennas acting as transmitting or the receiving sensors create one or more control fields and electromagnetic energy is transmitted through the object to be inspected by the antennas depending on its geometry and / or conductivity, whereby the antennas They are fed with different phases and the transmitted energy is fed to a connected selective amplifier (14) to which a phase comparison circuit, special filters for suppressing interfering and foreign energy are connected to suppress the interfering energies and the basic conductivity of the objects to be inspected, e.g. an evaluation unit which is arranged to allow the classification of electrically conductive protective strips, strips, fibers, or surface protection zones, wherein the inspected object is guided in a controlled manner during the inspection by these inspection fields in an undefined lateral position. Method according to claim 1, characterized in that the evaluation electronics consists essentially of a digital / analog converter and a controller or an integration Also, the circuit (15), the trigger circuit (16), the controller, the monostable flip-flop (17) and / or the product gate (18) determine from the waveform at the output of the selective amplifier (14) the limit amplitude (A) currency of a specific time interval (tk). Method according to claim 1 or 2, characterized in that the authenticity classification is carried out by means of the evaluation electronics such that a limit amplitude (A) is determined for the authenticity of the currency to be checked. Method according to claim 1 or 2, characterized in that the classification of the various banknotes and / or securities is carried out by means of the evaluation electronics such that a currency-specific time interval (tk) is determined by means of a controller and sorted objects are sorted according to time intervals (tl..tk-1, tk + 1..tn). Method according to claim 4, characterized in that an additional authenticity check is performed for currencies with the same time intervals. Method according to claim 1 or 2, characterized in that the evaluation electronics, preferably one or more controllers, provide a signal to the device for storing individual classified objects in special compartments or column containers by comparing time intervals and / or voltages. Method according to claim 1 or 2, characterized in that the antennas and / or electrodes have a surface area that is transverse to the direction of transport of the objects to be inspected such that the protective strip or the fiber, even at a defined lateral play AND AND AND AND AND AND AND AND AND AND AND AND AND AND AND AND AND AND AND In any case, the antennas and / or electrodes to which they are inspected also travel at a defined distance, irrespective of whether the object to be inspected passes through its front or rear side. Method according to claim 1 or 2, characterized in that an additional check is carried out and the result thereof is mixed with the signal from the evaluation electronics by means of a product gate without having to change the software of the protected document processing device in question. Apparatus for checking protected documents with capacitive coupling elements, transmitting energy between a transmitter and a receiver by bridging an electromagnetic field by electrically conductive protective strips, tapes or fibers or by means of protection areas, using evaluation electronics, for carrying out the method according to claim 1, characterized by comprising, in itself, document readers arranged optical sensors for activating capacitive control sensors, test fields which are formed in one or more planes by arranged sensors acting as transmitting or receiving antennas, a selective amplifier (14) and associated thereto a phase comparison circuit, special filters for suppressing disturbing and extraneous energies, and an evaluation unit consisting essentially of an analog / digital converter and a controller or an integration circuit (15), a trigger circuit du (16), a controller, a monostable flip-flop (17) and / or a product gate (18), the object being inspected in an undefined lateral position such that it is guided around the control sensors by brushes and / or pressure elements and / or conveyor belts (10), rollers, clamps and the like Even at a defined speed and in contactless contact. Apparatus according to claim 9, characterized in that the sensors acting as transmitting or receiving antennas are arranged as strip sensors (8, 9) in one plane or opposite and / or mirror-symmetrical in two planes. Device according to claim 9 or 10, characterized in that the strip sensors (8, 9) are provided with cut-outs or openings or windows (7) or are provided in the immediate vicinity of the strip sensors (8) , 9). Device according to one or more of the preceding claims 9 to 11, characterized in that the sensors of the control unit are arranged mirror-symmetrically to the control zones and / or protective strips, protective threads and / or protective strips of the objects to be inspected, in particular banknotes, securities. and packaging. Apparatus for checking protected documents having capacitive coupling elements, transmitting power between a transmitter and a receiver by bridging an electromagnetic field by electrically conductive protective strips, tapes or fibers or by surface protection areas and with evaluation electronics, for carrying out the method according to claim 1, characterized in that that the transmitting antennas (A2, A3, B2.1..B2.n) and the receiving antennas (A1, ΒΙ.Ι, .ΒΙ.η), forming together the control sensor (54), are arranged in such a way that it is possible to control both the through electrically conductive protective strips as well as those consisting of a plurality of electrically conductive but insulated sections, the control sensor (54) being arranged tangentially with a parallel displacement relative to the arc guide device (56) or tangentially with a parallel displacement relative to the transport roller (55) and two in counter-phase low or low o high frequency excited transmit antennas (A2, A3) are arranged perpendicular to the larger dimension of the security strip and perpendicular to the direction of movement of the document to be inspected, one or more receive antennas (A1) are aligned opposite to and between transmit antennas (A2, A3) a plurality of transmit antennas (B2.1..B2n) are arranged parallel to the transmit antennas (A2, A3) and multiple transmit antennas (B1.1..B1) are arranged parallel to the transmit antennas (B2.1..B2.n) wherein the adjacent transmit antennas (B2.i, B2.I + 1) and the respective reception antennas (B1.1, B1.i + 1) are arranged offset by a defined distance, preferably a distance between the transmit antenna (B2 .i) and the respective receiving antenna (B1.i) and the minimum distance from the transmitting antenna (B2.i) to the respective receiving antenna (B1.i) is less than the smallest distance between one of the transmitting antennas (A2, A3) and the receiving antenna antenna (Al). Apparatus according to claim 13, characterized in that the transmitting antennas (A2, A3, B2.1..B2.n) and the receiving antennas (A1, ΒΙ.Ι, .ΒΙ.η) are arranged over the entire document retrieval width. in a document processing facility. Device according to claim 13 or 14, characterized in that the transmitting antennas (A2, A3, B2.1..B2.n) and the receiving antennas (A1, ΒΙ.Ι, .ΒΙ.η) are side by side, parallel to each other. and offset in a plane such that the authenticity check of documents is performed between the two edges of the document independently of the side and edge of the document. Apparatus according to claim 13, characterized in that the receiving antennas (B1.1..Bl.n) and the transmitting antennas (B2.1..B2.n) parallel to the transport direction are spaced such that each of the inspected security elements, independently of their arrangement on the document, travels at least one receiving antenna (B1.B.n.n) and the respective transmitting antenna (B2.1..B2.n). Device according to claim 13, characterized in that the longer side of the transmitting antenna (B2.i) and the longer side of the respective receiving antenna (B1.i) correspond to the width of the conductive security element of the security strip. Device according to claim 13, characterized in that the switching or adjusting elements, in particular the microprocessor (47), the rectifier (45, 48, 49, 50) and the selective amplifier (46, 51, 52, 53) are controlled by the operator or software. are arranged such that the output signals of the selective amplifiers (46, 51, 52, 53) can be combined or logically coupled. Device according to claim 13, characterized in that the switching or adjusting elements, in particular the microprocessor (47), the rectifier (45, 48, 49, 50) and the selective amplifier (46, 51, 52, 53) are controlled by the operator or software. are arranged in such a way that it is possible to switch between different types and types of documents and their degree of wear without changing the sensor arrangement. Device according to claim 13, characterized in that the smallest distance between two transmitting antennas (B2.i) arranged in a row is greater than the smallest distance between two electrically conductive insulating protective fiber elements and the switching elements are arranged such that the antenna (A3) can be used as either a transmitting or receiving antenna, depending on the feed of the document being checked. Apparatus according to claim 13, characterized in that the software and / or the manually controlled switching elements are arranged such that one or more transmit antennas (B2.i) and respective receive antennas (B1.i) can be optionally activated or deactivated. .