JP2000242825A - Document checker having inductive sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a document (paper money, for instance) checker having an inductive sensor. SOLUTION: The document checker has a document passage 12 through which a document is carried and the inductive sensor for detecting the features of the document. The sensor has a 1st inductive element 40 arranged on the 1st side of the plane of the document passage 12 and a 2nd inductive element 42 arranged on the 2nd side of the plane of the document passage. A circuit connected to the output of the sensor processes a signal related to judgment of at least one of the existence, authenticity and money sort of an inserted document. When a document such as paper money is carried along the document passage, the sensor is not required to physically come into contact with the document.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates generally to a document validator having an inductive sensor.

[0002]

BACKGROUND OF THE INVENTION Documents, such as banknotes, may contain magnetic or other metallic "signs" to help detect and prevent counterfeiting. For example, ink and dye having magnetic properties are printed on banknotes. Thus, the portrait appearing in the center of various US banknotes is printed exclusively with magnetic ink. Similarly, the engraving that forms the printed contour of the US banknote is printed with magnetic ink. The magnetic properties are controlled to generate a limited magnetic signature or pattern associated with the real note.

[0003] Such magnetic properties can be detected, for example, with a banknote or bill validator. Some bill validators detect a magnetic signature associated with a bill or other document inserted into the validator by pressing the inserted document against a magnetic head or sensor.
When the magnetic sensor contacts the document, the sensor detects the magnetic field created by the ink. The detected magnetic field is used to determine the validity of the inserted document.

[0004]

However, as a result of continuous contact with banknotes or other documents, dirt or other debris will stick to the magnetic head. The debris can contaminate the magnetic head and degrade the performance of the checker if the magnetic head is not cleaned regularly. Also, the ability of the validator to handle worn or damaged bills may be reduced if contact with documents is required to validate the bill. Further, when the bill is pressed against the sensor with too much force, the bill may be jammed in the passage of the checker.

While the use of non-contact magnetic sensors is desirable, the fact that the strength of the magnetic field decreases as the distance of the sensor from the bill increases increases the traditional use of non-contact magnetic sensors in banknotes or banknote validators. Had been restricted.

[0006]

SUMMARY OF THE INVENTION In general, in one aspect, a document validator includes a document path through which a document is conveyed, and an inductive sensor for detecting document characteristics. The sensor includes a first inductive element located on a first side of the plane of the document path and a second inductive element located on a second side of the plane of the document path. . Circuitry connected to the output of the inductive sensor processes signals related to the determination of at least one of the presence, authenticity and denomination of the inserted document.

In accordance with another aspect, a method for determining document characteristics includes transporting the document along a path and detecting the document characteristics using inductive sensors. The inductive sensor includes a first inductive element located on a first side of the plane of the passage and a second inductive element located on a second side of the plane of the passage. The signal from the output of the sensor is processed to determine at least one of the presence, authenticity and denomination of the document.

[0008] Various implementations may include one or more of the following features. Inductive sensors can include a transformer coupled oscillator. The first and second inductive elements can include a coil wound on a ferrite core such as a pot core. The sensor is a magnetic feature of the inserted document,
For example, magnetic ink, or conductive features of a document, such as security lines, can be detected. The oscillator can have a resonant frequency that allows the sensitivity of the sensor to be selected to take full advantage of either frequency or amplitude changes.

[0009] The inductive sensor is arranged to detect document features without physically touching the document. For example, the inductive element is located at least several tens of millimeters from the document path. Further, the inductive elements are located substantially opposite each other on each side of the document path. The verifier may include an upper housing and a lower housing. One inductive element is located in the upper housing and the other inductive element is located in the lower housing. The inductive element is arranged to detect magnetic or conductive features near a side edge of the document parallel to the direction of travel along the document path.

[0010] The circuit is configured to detect a change in the frequency or amplitude of the signal at the sensor output. Further, the verifier can include an automatic gain control circuit to control the bias voltage of the sensor.

A processor or other controller may compare the data obtained from the sensors with at least one statistically determined threshold to determine the authenticity of the document. The processor can also compare the data obtained from the sensors with one or more patterns. This pattern corresponds to a genuine document and is used to determine whether the document is genuine based on a comparison. In some embodiments, a binary magnetic pattern of a document can be detected. The detected pattern is compared with a stored pattern to determine the authenticity and denomination of the document.

[0012] In some embodiments, the data is:
The sensor obtains not only when there is a document in the document path but also when there is no document in the document path. An arithmetic operation using both data when there is no document and when there is a document is executed. At least one of the authenticity and the denomination of the document is determined based on a result of the calculation operation.

[0013] Two or more inductive sensors can be used in one validator. The details of the various inductive sensors, such as dimensions, oscillating frequency or other characteristics, may vary depending on the particular implementation.

[0014] Various embodiments provide one or more of the following advantages. Increased sensitivity to the magnetic and conductive properties of the document is achieved. The validator can detect used or damaged documents with improved accuracy. The magnetic and conductive features of a bill or other document can be detected without pressing the bill against the sensor and without requiring contact between the bill and the sensor. further,
Resonant circuits are relatively resistant to stray magnetic fields, such as the earth's magnetic field. The gap between the sensor and the bill passage can be increased to reduce the likelihood of the bill becoming jammed in the validator and to reduce sensor wear.

The sensor is tuned to detect a document such as a US banknote having magnetic material thereon, or to detect a document such as a European banknote having a conductive security wire embedded therein. Thus, a wide range of operating frequencies can be used. Further, the detection and processing circuitry detects changes in frequency, amplitude, or both,
Not only the presence of such a document in the bill passage of the validator, but also the authenticity and denomination of the document can be determined.

[0016] Other features and advantages will be apparent from the following description, drawings, and claims.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, an exemplary bill validator 2 includes a confirmation unit 4, a transfer and stacking unit 6, and a cassette unit 8. The passage of a bill or other document through the validator 2 is indicated by the dotted line 12. Various features and details of the validator 2 are described, for example, in U.S. Pat.
No. 2,367.

The transfer device on one side of the bill path 12, for example above the bill path, includes multiple pairs of drive rollers 16,18 connected to drive rollers 14 by respective belts 20,22. A pair of spring-biased rollers 24, 26, 28 on opposite sides of the passage 12 are pressed against drive rollers 18, 20 to pinch the side edges of the bill parallel to the direction of bill movement.

The bill 10 inserted in the confirmation section 4 of the confirmation device 2
Are engaged by rollers 18 and 24 and conveyed through a number of confirmation sensors. The bills 10 are rollers 16, 26
And then go up the bend 30 and roll
Proceed to Banknotes 10 are conveyed to rollers 14 if acceptable. The rollers 14 carry the notes 10 to a position for stacking in the cassette 8 at the end of the note passage 12. If the bill 10 cannot be accepted, a motor (not shown) controlled by a control and processing circuit such as a microprocessor rotates in the reverse direction, and the bill is removed.

The confirmation section 4 includes a lower housing 32 and an upper housing 34 that define a bill entrance 36. The housings 32 and 34 include a plurality of optical sensors for detecting the presence of the bill inserted into the validator 2 and detecting various characteristics of the bill used to determine the authenticity and the denomination of the bill. (Not shown).

The confirmation unit 4 includes an inductive sensor 38. The sensor 38 is arranged, for example, close to the light sensor, in other words between the rollers 18, 24 and 16, 26. As shown in FIG. 2, the inductive sensor 38 includes a transformer coupled oscillator. The oscillator comprises a first inductive element 40 on one side of the plane formed by the bill path 12,
Second inductive element 42 on the opposite side of the bill path plane
Consists of In the embodiment shown in FIG. 2, one end of the first inductive element 40 is connected to the base 46 of the transistor 44.
And the other end is connected to a bias voltage (V _BIAS ). The capacitive element 52 is connected in parallel with the first inductive element 40. One end of the second inductive element 42 is connected to the collector 48 of the transistor 44 via the resistance element 60 and the coaxial cable 61, and the other end is connected to the power supply (V _CC ). The emitter 50 of the transistor 44 is connected to the ground (GND) via the resistance element 62. Resistance element 62 sets a bias current of transistor 44. The output of sensor 38 is taken from line 58 which is connected to emitter 50 of transistor 44.

Generally, the inductive elements 40 and 42 are arranged to face each other, and several tens of inches are provided between each inductive element and the bill passage.
Each gap 5 on the order of millimeters or more
4, 56 are formed. In one embodiment, inductive element 42 includes lower housing 32 (shown in FIG. 1).
The inductive element 40 is disposed within the upper housing 34.
Is placed within. Inductive elements 40, 42 allow sensors 38 to detect magnetic or conducted information near the side edges of the bill parallel to the direction of travel of the bill within each housing as the bill is carried along path 12. Attached so that you can.

Other sensor electronics can be mounted on a printed circuit board located in the upper housing 34. By using the inductive sensor 38, the magnetic and conductive features of the bill or other document 10 can be used without forcing the bill against the inductive elements 40, 42 and without requiring the bill to contact the inductive sensors 40, 42. It is possible to be detected.

In operation, the electromagnetic coupling between the inductive elements 40, 42 provides positive feedback, resulting in an oscillating state. Banknotes or other documents with conductive or magnetic material 1
0 moves along the bill passage 12, and the inductive elements 40, 4
When passing between the two, a phase change in the magnetic field is induced in the transformer coupled oscillator. At the time of response, the oscillation amplitude and frequency change so as to compensate for the phase change and maintain the oscillation state. The measurement of frequency shift, amplitude change, or both, provides an indication of the conductive or magnetic characteristics of the document 10.
Measurement and processing circuitry is then used to process the signals representing the detected features and determine or confirm the presence, authenticity and / or denomination of the document 10 based on the frequency or amplitude changes.

The inductive elements 40 and 42 can take various forms including a coil wound around a bobbin and a ferrite core, for example. The shielding provided by the ferrite pot core can help reduce interference. However, other cores, such as U-core, C-core and E-core, can also be used. In one embodiment, 0.4 mm
6.5 turns of copper wire having a diameter of .about.7 mm were wound on a 7 mm ferrite pot core to provide an inductance of 90 nanohenries (nH). In general, the size of the core is chosen as a compromise between the size of the document feature to be detected and the distance between the pot cores. For example, in the case of US banknotes, if the core is too large, the sensor 38
Will detect a combination of magnetic and non-magnetic inks. If the cores are too small, the leakage flux across the poles of each core will be high compared to the flux across the gap between the pot cores, resulting in poor detection of banknote features.

In general, testing for resonance frequencies greater than about 1 megahertz (MHz) indicates that the magnitude of the frequency shift increases with increasing operating frequency, but the magnitude of the amplitude change decreases with increasing frequency. showed that. Thus, in one embodiment, the frequency shift of a document containing magnetic ink was just detectable using a frequency as low as about 14 MHz. If a document containing a conductive security line and magnetic ink is detected using a 7 mm ferrite core, the resonant frequency of about 25 MHz will be about 12 kHz (kHz) and 4 kHz, respectively.
Frequency shift. Also, resonance frequencies greater than 25 MHz can be used. Resonant frequencies below 14 MHz tended to give stronger amplitude responses to documents containing conductive security lines, such as those found in some European banknotes.

As shown in FIG. 3, the output of sensor 38 drives a frequency buffer 70, which converts a small oscillating signal from sensor output 58 to a digital level signal. The digital signal is then used to determine the frequency of the signal from sensor output 58. In one embodiment, for example, the first counter 72
Generates a counter gating period using a 16 MHz crystal, a 1.792 milliseconds (ms) counter gating period corresponding to approximately 3 samples per millimeter of bills traveling along the bill path 12, 2.048 ms Occurs every time. The second 16-bit counter 74 receives and counts the number of zero crossings that occurred during the counter gate period. The resulting count is transferred to a memory, for example, a random access memory (RAM) 76 during the subsequent 0.256 ms. In this embodiment, the maximum input frequency corresponding to the overflow of the 16-bit counter 74 is 36 with a resolution of 0.5 kHz.
MHz.

The idle count, or air value, is determined by determining the average number of cellocrossings that occur during the counter gate period when there is no paper near sensor 38. The bill is moved along the bill passage 12 by the sensor 38.
, The number of cellocrossings during each counter gate period is counted,
It is stored in the memory 76. Microprocessor 78 or other suitable processor or controller subtracts the idle count from each count measured when document 10 is present. The resulting difference is then converted to a corresponding frequency shift.

Microprocessor 78 is programmed using any of several known techniques to analyze the acquired data and compare it to the magnetic or conductive characteristics of acceptable bills or other documents. ing. For example, data obtained from the sensor 38 is compared to one or more statistically determined thresholds to determine the validity of the document. Similarly, the predetermined magnetic and conductive patterns of a genuine bill are electrically erasable in a programmable read only memory (EE).
(PROM) 82. Microprocessor 78
Uses a predetermined pattern and acquired data to determine whether the bill is genuine and, if so, the denomination of the bill. In one embodiment, sensor 38 detects a binary magnetic or conductive pattern of the bill, and the detected pattern is compared to a stored pattern to determine the authenticity, denomination, or both, of the bill. The binary pattern is formed, for example, by alternating the presence and absence of magnetic material along the edge of the bill. The bill is then accepted or rejected based on the result of the comparison. Also, other magnetic or conductive patterns can be used.

[0030] In another embodiment, the frequency measurement and processing circuit includes a synchronization acquisition loop. For example, the inductive sensor 38 is tuned with a varicap diode driven by a phase detector. The reference signal obtained from the crystal serves as the input to the phase detector, so that the idle frequency is synchronously captured by the crystal. When a bill having a magnetic or conductive material passes between the inductive elements 40 and 42, disturbance occurs in driving the varicap. Therefore, frequency modulation caused by magnetic or conductive materials is manifested as control voltage modulation. The disturbance is measured using, for example, an analog-to-digital (A / D) converter.

If the coupling between the inductive elements 40, 42 is relatively weak, slight disturbances in environmental changes, such as mechanical tolerances of circuit components or changes in ambient temperature, will change the operating state of the oscillator. Therefore, oscillation may no longer occur. To compensate for such an event, as shown in FIG. 3, an automatic gain control circuit is provided to control the bias voltage V _BIAS applied to the inductive element 40 to maintain the oscillation state. Specifically, the emitter 5
The sensor output 58 from 0 drives the amplitude detection circuit 64. The output of the amplitude detection circuit 64 is
Connected to. The output of the automatic gain control circuit 66 is connected to a low pass filter 68 to control the bias voltage of the transistor 44 to maintain a substantially constant peak-to-peak voltage of the emitter 50.

The output of the amplitude detector 64 is also connected to an amplitude processing circuit 80, which converts the received signal into a format suitable for subsequent processing by the microprocessor 78. Thus, the sensor 38
The change in the amplitude of the output of the microprocessor 7 is detected.
8 to determine the authenticity and denomination of the inserted bill. Amplitude change detection is used, for example, to detect some European banknote features, including conductive security lines. It has been found that an oscillation frequency of the sensor 38 in the range of about 1-2 MHz provides a strong amplitude response when some of these bills are examined.

FIG. 4 shows further details of various circuit components according to one embodiment. The inductive sensor 38 includes a transmitting coil L2, a receiving coil L1, resistors R1, R4, and R5.
, A capacitor C1 and an NPN transistor Q1. The coils L1 and L2 are wound around a ferrite pot core, are substantially equivalent, and are arranged on both sides of the plane of the bill passage 12. The driving side of the sensor 38 is connected to the collector of the transistor Q1, and the adjustment side is connected to the base of the transistor Q1. As shown in FIG. 4A, the output of sensor 38 is connected to frequency buffer 70 by transformer T1 and associated circuitry. Frequency buffer 70 includes a feedback resistor R17 and an inverter U3 with AC input coupling. Isolated power supplies are provided for the inductive sensor circuit and the frequency counting logic. The output of the frequency buffer 70 is connected to a frequency counting and processing circuit including counters 72 and 74, memories 76 and 82 and a microprocessor 78 as shown in FIG. In another embodiment, the output of frequency buffer 70 is the output of transistor Q1 or transistor Q1.
2 can be obtained directly.

The output of the sensor 38 is supplied to the amplitude detector 6
4 is also driven. Amplitude detector 64 includes a PNP emitter follower transistor Q2 and an active diode pump consisting of diode D1 and transistor Q3. The amplitude detector 64 also includes a PNP emitter follower transistor Q4 and a diode D2. The output of the amplitude detector 64 is connected to an additional amplitude processing circuit, which includes an A / D converter 86 (FIG. 4B) whose output is connected to a microprocessor 78. Thus, for example, if the amplitude of the oscillation of the sensor 38 decreases due to the presence of a bill containing a conductive material, the output voltage of the amplitude detector 64 decreases. The output voltage of the amplitude detector 64 is A
The digital signal is converted by the / D converter 86. The microprocessor 78 processes this digital signal,
Determine the change in amplitude. The amplitude changes corresponding to multiple points along the document are then used to assess the authenticity and denomination of the note.

The output of the amplitude detector 64 is also connected to an automatic gain control circuit 66. As shown in FIG. 4B, the automatic gain control circuit 66 includes an operational amplifier U1. The operational amplifier U1 amplifies an offset between the output of the amplitude detector 64 and the voltage set by the potentiometer VR1. The normal setting of automatic gain control circuit 66 provides a 2 volt bias to the base of transistor Q1 of inductive sensor 38. Therefore, for example, when the oscillation amplitude of the sensor 38 decreases due to the presence of a bill containing a conductive material, the output voltage of the amplitude detector 64 decreases and the output voltage of the automatic gain control circuit 66 increases. Then, the bias of the transistor Q1 of the inductive sensor circuit 38 increases, thereby increasing the oscillation amplitude and compensating for the original decrease.

As shown in FIG. 4B, the output of the automatic gain control circuit 66 is also connected to a disturbance detector 84, and a change in the output of the automatic gain control circuit 66 is monitored. The disturbance detector 84 enables the amplitude change of the output of the sensor 38 to be detected indirectly. Disturbance detector 84
Is used to detect the presence of a banknote with a conductive security line or magnetic ink. Thus, for example, if the output of automatic gain control circuit 66 increases, the instantaneous voltage on capacitor C8 remains constant, and the output of comparator U2 switches from a high signal to a low signal. Microprocessor 78 detects the low signal and interprets it as an indication that a document having conductive or magnetic characteristics is present in the bill path.

Typical values of the resistors R1 to R21, the capacitors C1 to C13, and the inductors L1 and L2 are shown in Table 1 below.

[Table 1]

For frequencies greater than about 10 MHz,
The resistor R1 can be omitted from the circuit. Thus, for example, using a value of 900 nH for L1 and L2 and a value of 22 pF for C1, the circuit becomes:
Resonates at about 36 MHz. For frequencies below about 10 MHz, a value of 33 pF is used as C1 and resistor R1 is included in the circuit.

Although many different devices are available to implement the particular circuit of FIG. 4, the LM358 devices manufactured by National Semiconductor are referred to as U1, U
2 and the Philips 1N4148 device can be used as diodes D1 and D2.
Similarly, a 74AC04 device manufactured by Motorola can be used as inverters U3 and U4 with a decoupling capacitor having a value of 47 nF connected between pins V _CC and GND. Transistors Q1, Q3
And Q4 can be implemented using a Motorola BC847B device, and transistor Q2 can be implemented using a Motorola ZN4403 device.

A plurality of inductive sensors similar to the sensor 38 can be incorporated in one document validator 2. For example, these inductive sensors may be positioned along the document path 12 to detect magnetic or conductive properties along two sides of the document as the document moves along the document path 12. it can. In one embodiment, as shown in FIG. 5, two inductive sensors 38 ', 38 ", each of which is the same as sensor 38, have a magnetic field near both sides of the bill parallel to the direction of travel of the bill. Or attached to the validator to allow detection of conduction information.The detection of magnetic or conductive features along both sides is based on the fact that this technique is independent of the direction of the bill when inserted into the validator. The sensors 38 ', 38 "can be substantially the same or different from one another in various ways. For example, the physical dimensions of the sensors 38 ', 38 ", such as the size of the inductive element, can be different from one another, with the larger sensor being positioned to detect features along one edge of the bill. ,
A smaller sensor is positioned to detect a feature along a second edge of the bill. Also, two sensors 3
Other details of the 8 ', 38 ", such as the oscillation frequency, can also be varied depending on the particular application.

Similarly, the set of inductive sensors described above comprises:
It can be arranged to detect features along one or both edges of the banknote. For example, in one embodiment, a large sensor and a small sensor are arranged to detect banknote features along one edge. In another embodiment, sensors having different oscillation frequencies can be arranged to detect banknote features along one of the edges parallel to the direction of travel of the banknote. In another embodiment, each set of sensors is arranged to detect banknote features along both edges of the banknote parallel to the direction of travel of the banknote. Each set may include, for example, a small sensor and a large sensor, or a plurality of sensors having different oscillation frequencies. In general, the number of inductive sensors located along a bill path need not be substantially the same, but in some situations it is advantageous to use substantially the same inductive sensors.

[0042] Other embodiments are within the following claims.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional side view of an exemplary document validator.

FIG. 2 is a block diagram showing an inductive sensor circuit used in a document validator.

FIG. 3 is a block diagram illustrating additional components of a verifier associated with an inductive sensor circuit.

FIG. 4A is a circuit diagram showing further details of the document validator.

FIG. 4B is a circuit diagram showing further details of the document validator.

FIG. 5 is a partial cross-sectional plan view of a document validator having a plurality of inductive sensors.

Continued on front page F term (reference) 2F063 AA50 BA30 BC09 BD17 DA01 DA05 DD03 GA01 GA29 LA04 LA05 3E041 AA02 AA03 AA04 BA09 BA20 BB07 CA01 CA02 CB02 CB03 CB08 EA01

Claims (48)

[Claims] 1. A document path in which a document is conveyed, an inductive sensor for detecting characteristics of the document, a first inductive element disposed on a first side of a plane of the document path, A sensor comprising a second inductive element disposed on a second side of the plane; and at least one of the presence, authenticity and denomination of an inserted document connected to the output of the inductive sensor. And a circuit for processing signals related to the document. 2. The document validator according to claim 1, wherein said inductive sensor comprises a transformer-coupled oscillator. 3. The document validator of claim 2, wherein the first and second inductive elements are disposed substantially opposite each other on each side of the document path. 4. The document validator according to claim 2, wherein the inductive sensor detects a characteristic of the document without physically contacting the document. 5. The document validator according to claim 2, wherein said first and second inductive elements comprise a coil wound around a ferrite core. 6. The document validator according to claim 2, wherein said first and second inductive elements comprise a coil wound around a ferrite pot core. 7. The document validator of claim 2, wherein the circuit is configured to detect a frequency change of a signal at the sensor output. 8. The document validator of claim 2, wherein the circuit is configured to detect a change in the amplitude of a signal at the sensor output. 9. The document validator according to claim 2, wherein the sensor detects a magnetic characteristic of the inserted document. 10. The document checker according to claim 9, wherein
The sensor is a document validator that detects magnetic ink on the document. 11. The document checker according to claim 2, wherein
The sensor is a document validator that detects a conductive feature of the document. 12. The document validator according to claim 11, wherein a conductive security line in the document is detected. 13. The document checker according to claim 2, wherein:
A document validator wherein the first and second inductive elements are located at least a few tens of millimeters from a document path. 14. The document checker according to claim 2, wherein
In addition, including an upper housing and a lower housing,
A document validator wherein the first inductive element is located in an upper housing and the second inductive element is located in a lower housing. 15. The document checker according to claim 2, wherein
A document validator, wherein the inductive element is arranged to detect a magnetic feature near a side edge of the document parallel to the direction of travel along the document path. 16. The document checker according to claim 2, wherein:
A document validator wherein the oscillator has a resonance frequency in the range of about 1-2 megahertz. 17. The document validator of claim 16, wherein the oscillator has a resonant frequency of about 25 megahertz. 18. The document checker according to claim 2, wherein
A document validator wherein the oscillator has a resonance frequency in the range of about 1-30 MHz. 19. The document checker according to claim 2, wherein
A document validator wherein the first inductive element is connected to a base of a transistor, the second inductive element is connected to a collector of the transistor, and the processing circuit is connected to an emitter of the transistor. 20. The document validator according to claim 19, further comprising an automatic gain control circuit for controlling a bias voltage of the transistor. 21. The document checker according to claim 1, wherein
A document validator including a processor programmed to compare data obtained from the sensors to at least one statistically determined threshold to determine the authenticity of the document. 22. The document checker according to claim 1, wherein:
A processor programmed to compare data obtained from the sensor with one or more predetermined patterns corresponding to a genuine document and to determine whether the document is genuine based on the comparison. Including a document validator. 23. The document checker according to claim 1, wherein
Document validation including a processor programmed to compare data obtained from the sensor with one or more predetermined patterns corresponding to a genuine document and determine the denomination of the document based on the comparison. vessel. 24. The document checker according to claim 1, wherein
Acquiring data from the sensor when the document is missing in the document path, acquiring data from the sensor when the document is present, performing an arithmetic operation using both the data acquired when the document is missing and when the document is present, and the result of the arithmetic operation A document validator comprising a processor programmed to determine at least one of the authenticity and the denomination of the document based on the document. 25. A document path in which a document is carried, and a plurality of inductive sensors for detecting a characteristic of the document, each sensor comprising a first inductive sensor disposed on a first side of a plane of the document path.
An inductive element, and a second inductive element disposed on a second side of the plane of the document path, and the presence of an inserted document connected to the output of the inductive sensor. A circuit for processing a signal related to a determination of at least one of gender and denomination. 26. The document validator according to claim 25, wherein the inductive sensor detects a characteristic of the document without physically touching the document. 27. The document validator of claim 26, wherein the inductive element of the first of the sensors is near a first side edge of the document parallel to its direction of travel along the document path. The inductive element of the second of the sensors is arranged to detect a magnetic feature, the inductive element of the second sensor detecting the magnetic feature near a second different side edge of the document parallel to its direction of travel along the document path. Document checker that is arranged to be. 28. The document validator of claim 27, wherein the first and second sensors have different dimensions. 29. The document validator according to claim 27, wherein said first and second sensors comprise transformer-coupled oscillators having different oscillation frequencies. 30. The document validator of claim 26, wherein the inductive element of at least some of the sensors has a first side edge of the document parallel to its direction of travel along the document path. A document validator located nearby to detect magnetic features. 31. The document validator of claim 30, wherein at least some of the sensors arranged to detect magnetic features near the first side edge of the document have different dimensions. Document checker to have. 32. The document validator of claim 30, wherein at least some of the sensors arranged to detect magnetic features near the first side edge of the document have different oscillations. A document validator that is a transformer coupled oscillator having a frequency. 33. The document validator of claim 26, wherein the inductive elements of the first set of sensors are magnetic near a first side edge of the document parallel to its direction of travel along the document path. The inductive element of the second set of sensors is arranged to detect a feature and is arranged to detect a magnetic feature near a second different side edge of the document parallel to the direction of travel. Document checker. 34. The document validator of claim 33, wherein at least some of the sensors in each set of sensors have dimensions that are different from dimensions of other sensors in the same set. 35. The document validator of claim 33, wherein at least some of the sensors in each set of sensors comprise a transformer coupled oscillator having an oscillation frequency that is different from the oscillation frequency of other sensors in the same set. Document checker. 36. A method for detecting a characteristic of a document, the method comprising: transporting a document along a path; a first inductive element disposed on a first side of a plane of the path; A second inductive element disposed on the side of the document to detect features of the document and process signals from the output of the sensor to determine the presence, authenticity or denomination of the document. Determining at least one of the following. 37. The method of claim 36, further comprising detecting a change in frequency of the output of the sensor. 38. The method according to claim 36, further comprising detecting a change in amplitude of the output of the sensor. 39. The method of claim 36, further comprising positioning the sensor with respect to the passage such that the sensor detects document features without physically contacting the document. 40. The method of claim 36, further comprising detecting a magnetic feature of the document. 41. The method of claim 36, further comprising detecting a conductive feature of the document. 42. The method of claim 36, further comprising controlling a bias voltage applied to the sensor. 43. The method of claim 36, further comprising comparing data obtained from the sensor to at least one statistically determined threshold to determine the authenticity of the document. 44. The method of claim 36, further comprising comparing the data obtained from the sensors to one or more predetermined patterns corresponding to the application document, and based on the comparison, A method comprising determining whether it is authentic. 45. The method of claim 36, further comprising comparing the data obtained from the sensors to one or more predetermined patterns corresponding to the application document, and based on the comparison, A method comprising determining a denomination. 46. The method of claim 36, wherein data is acquired from the sensor when a document is missing in the document path, data is acquired from the sensor when the document is present, and data acquired when the document is missing and present. A method for performing an arithmetic operation to be used in combination, and determining at least one of authenticity and denomination of a document based on a result of the arithmetic operation. 47. The method of claim 36, further comprising detecting a binary magnetic pattern on the document and comparing the detected pattern with a stored pattern to determine the authenticity of the document. 48. The method of claim 36, further comprising detecting a binary magnetic pattern on the document and comparing the detected pattern with a stored pattern to determine the denomination of the document.