GB2088051A

GB2088051A - Document Validating Apparatus

Info

Publication number: GB2088051A
Application number: GB8135401A
Authority: GB
Original assignee: Rowe International Inc
Current assignee: Rowe International Inc
Priority date: 1980-11-24
Filing date: 1981-11-24
Publication date: 1982-06-03
Also published as: CH649856A5; FR2494874A1; DE3146447A1; JPS57114988A; GB2088051B; FR2494874B1; CA1164100A

Abstract

A document validator in which a document is transported along a path from an entrance 12 past an array 68 of photoresponsive elements. In response to the arrival of the document at one or more predetermined positions 60 along the path, an area or areas thereof are illuminated and reflected light is directed to the photosensitive elements. A microprocessor extracts from the illuminated array the number of elements activated to a predetermined level and, compares this number with minimum and maximum numbers for an acceptable document and produces a validating signal when the number falls within the minimum and maximum limits but a rejecting signal when it falls without. The microprocessor may feed information to the memories carrying the minimum and maximum numbers in response to documents to cause the validator to "learn" a different document. Such validator is readily adapted to validate a plurality of documents of different types. <IMAGE>

Description

SPECIFICATION Document Validating Apparatus The present invention relates to apparatus for validating documents.

Many systems are known in the prior art for validating documents, and particularly for validating pieces of currency either to permit change to be given or to establish a credit for the sale of goods or services. These systems of the prior art operate generally on either one of or a combination of two different principles. First, light from a source may be directed toward the document to be validated and either reflected or transmitted light may be sensed to determine an optical characteristic of the document under test.

Alternatively and particularly with United States currency, magnetic properties of the ink with which the bill is printed may be sensed in the course of the validating operation. Combinations of the optical and magnetic arrangements may be employed.

While the arrangements of the prior art for validating documents operate more or less successfully, they suffer from a number of disadvantages. First, they are not as versatile as is desirable, in that most of them are limited to the validation of one particular type of document, such for example as United States one dollar bill, or a United States five dollar bill. Secondly, they are not as reliable as is desirable, in that many of them will reject what is a genuine document, while at the same time accepting a bogus document. A further defect of document validators of the prior art is that, once they are set up for validation of a document of a particular type, they cannot readily be altered to accept a document of a different type.

The present invention provides apparatus for validating documents comprising a plurality of radiation responsive elements, a source of said radiation, means for positioning a document to be validated so that radiation from said source is directed over a portion of the positioned document and thence to said elements, means for producing an indication corresponding to the number of said elements activated to a predetermined level in response to radiation from said portion of the document, means for comparing said indication with minimum and maximum limits respectively corresponding to minimum and maximum numbers of elements to be activated to said predetermined level in response to a valid document, and means responsive to said comparing means for indicating whether or not the document is valid.

A preferred embodiment of the invention is readily capable of validating a document of more than a single type, and can readily be changed to validate a document of a different type fromthat for which the validator was initially set.

The radiation used in the apparatus is preferably light.

In the preferred apparatus, a document is transported along a path from an entrance toward an exit past an array of a plurality of photoresponsive elements positioned at a predetermined location along the path. In response to the arrival of the document at one or more predetermined positions along the path, an area or areas thereof are illuminated and light from the illuminated area is directed over the array of photosensitive elements.A microprocessor unit extracts from the illuminated array pictures of the areas in terms of the number of elements thereof activated to a predetermined level and, for each picture, compares this element with a first stored number, corresponding to the minimum number of elements which must be illuminated for an acceptable document and with a second number corresponding to the maximum number of elements which should be illuminated for an acceptable document to produce a validating signal when the number of activated elements for each picture falls within the limits determined by the first and second numbers and for rejecting the document when the activated number of elements is outside the limits.The microprocessor unit of the document validator is preferably adapted to be set up to feed information to the memories carrying the first and second numbers in response to documents passed through the system to cause the validator to "learn" to validate a different type of document. Such universal document validator is therefore readily adapted to be set up selectively to validate a plurality of documents of different types.

In order that the present invention may be more readily understood, an embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which like reference characters are used to indicate like parts in the various views, and in which: Figure 1 is a sectional view of one embodiment of the document validator of the invention; Figure 2 is a block diagram illustrating the various components of the document validator; Figure 3 is a schematic view illustrating a portion of the microprocessor circuitry of the document validator; Figure 4 is a schematic view of a further portion of the microprocessor circuitry of the document validator; Figure 5 is a schematic view of a still further portion of the microprocessor circuitry of the document validator;; Figure 6 is a schematic view of the photosensitive array and associated circuitry of the document validator; Figure 7 is a schematic view of the keyboard and selection switch system of the document validator; Figure 8 is a flow chart illustrating the first part of the initial portion of the general program of the microprocessor in the document validator; Figure 9 is a flow chart illustrating the final part of the initial portion of the general program; Figure 10 is a flow chart illustrating the program subroutine of restoring the previous limits in the microprocessor; Figure 11 is a flow chart illustrating the "learning" program subroutine of the microprocessor; and Figure 12 is a flow chart illustrating the validating program subroutine of the microprocessor in the document validator.

Referring now to Figure 1 of the drawings, the universal document validate includes a housing 10 having an inlet mouth 12 leading into the space between an upper guide 14 and a lower guide 16. The base 18 of the housing 10 supports a reversible motor 20, the shaft of which carries a sprocket wheel 22 adapted to drive a pitch chain 24. Chain 24 engages a first sprocket wheel 26 adapted to drive the lower roller 28 of a first pair of rollers including a pressure roller 30 urged into engagement with roller 28. The chain 24 extends around an idler sprocket 32 supported on the housing 10 in such a manner as to permit adjustment of the tension in the chain in a manner known to the art to a sprocket wheel 34 adapted to drive an intermediate roller 36 having associated therewith another roller 38, resiliently urged into engagement with the roller 36.From sprocket wheel 34 a chain 24 passes to a sprocket wheel 40 adapted to drive a lower roller 42 associated with an upper roller 44 resiliently urged into engagement with the lower roller 42.

From sprocket wheel 42, chain 24 extends around sprocket wheel 46 and back to the wheel 22. Wheel 48 is adapted to drive a roller 48 having an upper roller 50 associated therewith.

In one form of my universal document validator the leading edge of a document to be validated is inserted into the mouth 12, so as to interrupt the passage of light from a source 52 toward a detector 54. In response to this action, motor'20 is energized in the forward direction to cause roller 28 to advance the bill along the passage formed by the upper guide 14 and the lower guide 16. When the bill arrives at a predetermined location along the transport path, light from a source 56 is prevented from energizing a photocell 58 to a level sufficient to initiate further operation of the machine. Stated otherwise, interruption of this light beam either by the leading edge of the bill itself over by the leading edge of printing initiates further operation of my universal bill acceptor.I so arrange my system as to cause this bill position sensing system to start the validating operation, for example, when a predetermined area of the bill is over a window 60 formed in the lower guide 1 6. Window 60 is normally closed by a shutter 62 adapted to be opened upon the energization of a solenoid 63, for example. Preferably the side of the shutter 62 which is exposed to light when the shutter is closed is provided with a reflective pattern for calibration purposes.

When the window 60 is open and the validation operation is to take place, light from a source 64 is adapted to illuminate the area of the document above the window 60. Light reflected from the document is focussed by a lens 66 on an imaging chip 68 having an array 70 of 128 individual photosensitive elements, for example.

The microprocessor circuitry which is responsive to the various input signals of the system may be housed in any suitable subhousing, such for example as the subhousing 72 indicated schematically in Figure 1. As will more fully be explained hereinbelow, the elements of the array 70 may be polled a number of times in the course of passage of a document through the validator to provide as many "pictures" of predetermined areas of the document as desirable or as required.

Referring now to the block diagram of Figure 2, my validator includes a power supply 74 adapted to provide the proper potentials for operating the drive motor and for the logic units of the system from a source of alternating current at the installation at which my validator is used. More specifically, the supply 74 provides power for the transport drive 20, for the document position sensor including the elements 52, 54, 56 and 58, for the light source 64, for the image sensor unit 68, for the clock pulse generator 76, for the transport device controller logic 78, for the temporary data storage unit 80, for the data manipulation unit 82, for the validation decision unit 84, for the synchronizing unit 86, for the image sensor drive logic 88, and for the buffer memory 90.Clock pulse generator 76 provides input clock pulses for the transport device controller 78, for the temporary data storage unit 80, for the data manipulation unit 82, for the validation decision unit 84, for the synchronizing unit 86, for theimage sensor drive logic 88, and for the buffer memory 90. When a bill enters the transport system, the document position sensors 52, 54 put out a signal which actuates the transport device controller 78 through a channel 92 to provide a transport drive 20 with a forward drive signal on a channel 94. When the leading edge of the bill, or the leading edge of the printing reaches the sensing system 56, 58 an input signal is provided on a channel 96 to the synchronizing system, which at the proper point in time provides a synchronzing signal to the image sensor drive logic 88, on a channel 95, and to the buffer memory 90, on a channel 97. This document position signal can also be used to energize solenoid 63 to open the shutter 62. When an area of the bill or document from which the "picture" is to be taken arrives at the window 60, the image sensor 68 is polled to feed output data to the buffer memory 90 on a channel 98. Each "picture" comprises 128 output signals, which are compared with a threshold voltage to produce logical output "1 's" which may, for example, be 5 volt DC pulses, or "owts" which may, for example, be 0 volts DC. In response to synchronizing signal on channel 96, the information is fed from the buffer memory 90 to the temporary data storage unit 80 along a channel 99. In addition to the synchronizing signals already identified, the unit 86 provides a synchronizing signal to the units 80, 82 and 84 on channels 100, 102 and 104.

Respective channels106 and 108 provide twoway communication between units 80 and 82 and between units 82 and 84. Channel 110 provides two-way communication between 80 and 84.

Once the picture has been fed to the control system in the manner described, the data manipulation circuitry adds up the number of high level bits contained in the picture and stores the sum in the temporary storage register 80. The value of the picture is dependent upon the amount of light being reflected from the document which, in turn, is a function of the type and condition of the paper and ink used, as well as of the image imprinted on the document at the location at which the picture is taken. The summing of bits in this manner reduces the effect of the image being out of position as when the document is not precisely registered.

It is contemplated that as many pictures as desired may be taken, so that after the desired number of pictures has been taken, each of the pictures is in its own temporary storage register.

At this point, the validation process takes place by considering the value of each picture individually, or by arithmetically combining two or more of the picture values. The resultant values are then checked to determine whether or not they fall within predetermined limits for a valid document of the type under consideration. As will be pointed out more fuliy hereinbelow, the validator may contain acceptable limits for several different documents, in which case the picture data is checked to see if it falls within the acceptable limits of any of the document. Should the documents be determined to be validthe controller puts out a "valid" pulse on a channel 11 2 and the document continues to travel through the validator until it leaves the exit, at which point it may be stacked, in a manner known to the art.If it is determined that the bill is not valid, the circuit 84 puts out a signal on channel 114 indicating that the bill does not fall within the acceptable limits, so that circuit 78 puts out a signal on channel 94 causing the transport drive 20 to reverse to return the bill to the customer.

Referring now to Figures 3 to 5, there is shown the schematic diagram of the computer portion of the system along with some of the circuits for controlling the image sensor, the transport motor, and so forth. For purposes of clarity the interconnections between Figures 3 and 4 have been designated by the respective reference characters a to mm in the two figures. In an analogous manner the interconnections between Figures 4 and 5 have been designated by reference characters nn to eee in the two figures.

In the arrangement shown in these figures, Z1 is the central processing unit, which may, for example, be an Intel 8085A microprocessor. Z2 is an Intel 8355 chip providing a combination of program memory (ROM) and 1 6 lines of input or output. Z3 is an Intel 8155 chip affording a combination of working memory (RAM) a timer, and 22 lines of input or output. These three chips along with Z8, which seiects the chip with the central processing unit Z1 communicates, form the brain of the system. The CPU shares the lower 8 bits of address with 8 bits of data. Z3 is provided with a "learn" switch and with switches SW1 and SW2 which determines the mode of operation thereof in a manner known to the art.

Z4 which may, for example, be an Intel 8212, 8 bit input-output port holds constant the address bits, so that Z5 and Z6 may operate properly.

Each of Z5 and Z6 may, for example, be an Intel 5101 chip providing a 256 x4 bit static MOS RAM. Both Z5 and Z6 are powered by a plus 5 volt DC potential when power is on, and with a 2.4 volt battery when the power fails. Chips Z5 and Z6 contain the "learned" limits from a document and they may be cleared and new limits learned from a different document, if and when this is desired. It is to be understood that where two or more documents or bill types are provided, pairs of similar chips to Z5 and Z6 must be added. These additional pairs would be wired in precisely the same manner as Z5 and Z6, except that the first extra pair would have their CE1 pins (pin 19) tied to pin 11 of Z8 and the second pair would have the corresponding pins tied to pin 10 of Z8.By way of example and to avoid repetition, such extra types have been indivated by B in a circle adjacent to pin 11 of Z8 and C in a circle adjacent to pin 10 of Z8.

If power is lost, it is necessary that Z5 and Z6 be disabled. Z7 functions to detect such a power loss and to disable Z5 and Z6 in that manner. This chip also provides the proper sequencing for power down and power up, thus protecting the limits which must not be altered as a result of power failure.

Z9 is a divide by 1 6 counter, which divides the central processing unit's clock to provide clock pulse for the said sensor and which also provides the clock input to the timer Z3.

Z10 and Z1 1 make up a digital to analogue converter which is controlled by the port line Z2 to permit the central processing unit continually to correct for video variations by adjusting the threshold voltage to the video comparator. Z1 2 and Z1 6 count the number of video pulses which exceed the threshold and the resultant 8-bit picture is available to Z1 through 8 lines of Z3, Z1 4 is a seven segment display driven by seven lines of Z3 through a Darlingtion array Z1 3, which adds current to the input. This display device Z14 provides an indication to the service man of the status of the validator.

Z15 isa package of four operational amplifiers, which may be used to create a pulse on the edge of printing in response to the sensor 58. This circuit includes a switch which may be thrown, so that timing would begin on the edge of the bill, rather than at the edge of printing. Preferably, the edge of printing signal is used, rather then the edge of the document to minimize the effects of misregistration of the edge of printing with the edge of the document.

Z1 8 is the video comparator, the output of which will be logic "1" if the video level from an element on the chip exceeds the threshold, which is the output of the digital to analogue converter formed by Z10 and 1.The output of 218 is buffered through a transistor, so that it will have the necessary drive capabilities and is used as the input to the video counters Z1 2 and Z16.

Referring now to Figure 6, as has been explained hereinbefore, the image sensor Z1 9 is a linear array of 1 28 individual photoresponsive elements. It will readily be appreciated that a planar rather than a linear array might be employed. The sensor is provided with plus 5 volt and minus 10 volt supply potentials, together with a clock input and a start signal. The clock is provided by Z9 of Figure 3, which clock is the CPU clock divided by 2,4, 8, or 16. By way of example, we have shown the clock signal as being divided by 4 in the drawing.The start pulse signal is generated by the use of 3 up counters Z20, Z2 1 and Z22, which count clock pulses from a preloaded number set at a loading time with a number determined by 12 connections indicated as W1 to WI 2 in Figure 6. These up counters operate until Z22 produces a carry, which reloads the preset number again and the process repeats itself. The number set by the jumpers W1 and W1 2 then determines the time between video readouts from the chip Z1 9. As is indicated in Figure 6, a portion of the start signal is controlled from two places. That is, it is controlled from Z22 and from a transistor illustrated in Figure 4, with the two places being OR wired.The carry signal from Z22 is a free running signal which is repetitive without any supervision from the central processing unit. The other signal coming into this circuit labeled "start" in Figure 6 is generated by a combination of the edge of printing detector Z1 7 and the CPU. Its purpose is to reload the counters, so that the count is in synchronism with the bill position. As a bill is inserted into the mechanism, it is transported eventually to the location of the edge detector 58, which provides a pulse to the flip-flop of Z1 7 and to the central process unit. The flip-flop output is driven high, which pulls the start signal down to cause the counters Z20 to Z22 to reload, regardless of their present count. The CPU takes action and clears the flip-flop, which in turn "releases" the start signal and the count is resumed.Thus, the array is in synchronism with the position of the document. This start signal is also shown in Figure 4 as returning to the other flip-flop of Z1 7 through a transistor, effectively to provide the CPU with a latched start pulse, which normally lasts only one clock period, thereby allowing some time for the CPU to recognize that the pulse has occurred.

The video information from the image sensor is available as a difference in voltage at 2 pins. Thus, a differential amplifier, such for example as Z23 may be used to create a video signal to useful amplitude. The output of amplifier Z23 provides the input to the microprocessor circuitry illustrated in Figures 3 to 5.

Referring now to Figure 7, a support 11 6 carries the usual push-button array, indicated generally by the reference character 11 8 providing the keyboard input to the microprocessor illustrated in Figures 3 to 5. This support 11 6 likewise includes a readout display indicated generally by the reference character 120. I also provide an assembly of three-positions switches indicated generally by the reference character 122 for setting up the microprocessor to provide particular operations in my application of the microprocessor. More specifically, a "mode" switch 124 is adapted to be moved among three positions. The first position labeled "RES" indicates a condition or mode in which the microprocessor will reset previous limits.The second position of the switch indicated by the legend "LRN" indicates a learn mode, in which one set of the memory units of the microprocessor are provided with a set of limits against which future documents of a particular type are to be judged. In the third mode indicated by the legend "VAL", the system is set to "validate" or to determine whether of not the video output provided by a particular document falls within the limits theretofore set for that particular type of bill. A second three-position switch 1 26 indicates the "type" of document A, B, or C for which the unit is set to learn.A third three-position switch 128 is provided for special functions, which can, for example, be "read" indicated by the legend "RD", "CLEAR" indicated by the legend "CLR", or a special function in which the present limits are modified, which position is indicated by the legend "NLIM" in the figure.

The operation of my universal bill or document validator can best be understood by reference to the flow charts of Figures 8 to 12. At the start of the program the condition is such that the transport motor is off, the shutter 62 is closed, and the calibration image on the back of the shutter is in place. In a first step of operation, lamp 10 may be illuminated and potential applied to the control system. The resultant picture which is focused on the array 70 is compared with a stored calibration value, and, if the value is correct, the program proceeds. If not, the threshold voltage is adjusted and the comparison again made until the correct value is reached. At this point, a decision is made of whether or not there is a special function required. If so, the particular function is detected and is performed and the system returns to the start. It there is no special function required, the next decision is whether or not there has been document or bill inserted into the validator. If not, the program returns to the start. If so, the motor is started and the solenoid 63 is energized and the shutter 62 is withdrawn.

I may, if desired, provide may validator with a backside test for making a simple test on the backside of the document in question. Since such a test, per se, forms no part of my invention, the details thereof have not been shown. If such a test is provided, the backside circuitry is enabled at this time.

Next, the unit waits for the detection of the leading edge of printing in the preferred form. If no edge is detected within a reasonable length of time, the motor is reversed to return whatever has been inserted and the system returns to the start of the program. If the edge has been detected, my arrangement automatically synchronizes the array with the edge, so that the proper area on the bill is examined. This may require an optional step of waiting for the area to reach the window 60.

When the area does reach the window, the array is polled and the required picture or pictures are acquired and stored. If the system is to operate to create arithmetic picture data other then the simple pictures obtained, this is the next step in the routine. When that has been done, the function switches are polled to determine what operation is next to be performed. If the arrangement is set merely to examine the document as in the case in which it is desired to know what data is at a particular location on the document, once this information has been read out, the document can be cleared and stacked and the program returned to start.

If the function switch is so set as to cause the previous limits to be restored, the program continues as indicated in Figure 10, in which the limits first are put in the proper place. Next, the pointer is set to the temporary limits and a pointer is set to the proper limit area as determined by the document type switch. Next, the data at the temporary pointer is moved to the limit pointed. A determination is made of whether or not all limits have been transferred. If not, both pointers are moved to the next address, until all limits have been transferred, at which time the document is pulled through and stacked and the program returns to start.

If, following the preliminary portion of the program illustrated in Figures 8 and 9, the system has been set to a "learn" routine, the program continues as indicated in Figure 11. Referring to Figure 11, in the learn mode the first step is to put the limits in the proper place. Next, the limits are put in the temporary storage register. The pointer is set to the first data picture, then a pointer is set to the first limit of the proper type. This first limit will be the low limit of particular type. A comparison is made of the picture data with the set limit. If the data is less than the set limit, the data is then put into the lower limit register and the program continues. If the data is equal to or greater than the set limit, the program continues without putting the data in lower limit register.In continuing the program, a pointer is set to the next or upper limit of the picture and a comparison of the data to the limit is made. If the data is greater than the set upper limit, it is placed in the upper limit register and the program continues. If the data is less than or equal to the upper limit, a decision is made as to whether or not all pictures have been tested. If so, the document is cleared and stacked and the program returns to the start. If not, the pointer is set to the next picture data for comparison with the lower limit and the program continues. This operation continues until sufficient information has been fed to the system to afford a basis for validation.

Ignoring, for purposes of simplicity, arithmetic picture data which could involve negative numbers, it will be clear that the minimum possible lower limit is 0, wherein all elements of the array are dark and the maximum possible upper limit would be equal to the number of elements in the array, wherein all elements were illuminated. Before a learn process is started, the special function "CLEAR LIMITS" is carried out, which routine sets all lower limits at the maximum possible values and the upper limits at the minimum possible value. After the data has been taken from the document to be "learned", the process begins. In the routine, the type switches are polled, if more than one type of document is to be handled by the system, so that the new limits can be put in the proper memory area.First, the data of the first picture is compared to the first or lower limit in the limit memory and if it is less than that limit, the data is placed in the limit location. Next, the data picture number one is compared to the next or upper limit, and if it is greater than that limit, then the data is placed in the limit location. This is carried out until all picture data has been learned. More specifically, assuming that the clear limit's function has been executed and that there are 100 elements in the array, the first and second limit memory registers would contain 100 and 0, respectively. Assume that the first picture of an inserted document has a value of 55.The learn routine would see that 55 is less than 100 and that 55 is greater than 0, so that, as a result, the first and second limit memory registers would be set to 55, 55. If the first picture of the next document produced the number 50, the registers would be set to 50, 55. If the next was 57, the registers would be set to 50, 57. If a document with a value of 52 were than passed through, the limits would remain unchanged.

Outlined below is a specific example carried out on a type "B" document, using the "output limits" routine to produce the print-out. A four picture system for each document is used in this example with maximum picture value of 127. The first print-out was carried out after "CLEAR LIMITS" was executed. The second print-out followed passage of the first "learned document", which obviously produced pictures having values of 49, 53, 56 and 60. As can be seen, the second document produced "learned data" which was lower at all locations, while the third document was higher than the two preceding documents at the locations tested. Again, when a representative number of documents of the type in question have been learned, the system is set for validation of documents of this type.

Learning Type B READOUT AFTER "CLEAR LIMITS" LOO 1=127:000 L002=127:000 L003=127:000 L004=127:000 00 OF THIS TYPE BILL HAVE BEEN LEARNED READOUT AFTER FIRST DOCUMENT.

LOO 1=049:049 L002=053:053 L003=056:056 L004=060:060 01 OF THIS TYPE BILL HAVE BEEN LEARNED READOUT AFTER SECOND DOCUMENT LOO 1=022:049 L002=023:053 L003=028:056 L004=027 :060 02 OF THIS TYPE BILL HAVE BEEN LEARNED READOUT AFTER THIRD DOCUMENT L00 1=022:056 L002=023:059 L003=028:061 L004=027:062 03 OF THIS TYPE BILL HAVE BEEN LEARNED Where my validator is to perform the validating function, it follows the routine set forth in Figure 12. First, the limit pointer is set at the first and lower limit of the first type. The data pointer is set at the first picture and a comparison is made of the data to the limit. If the data is less than the limit, a decision is made as to whether or not this is a reject of the last type of document to be tested by the validator.If not, the limit pointer is set at the first or lower limit of the next type and a comparison is made between the data and this limit. If the decision is that it is a reject of the last type of document to be tested by the machine, the motor is reversed, the document is returned to the customer and the program returns to the start.

If the data is equal to or greater than the lower limit, the limit pointer is set to the next or upper limit and the data is compared to this limit. If the data is greater than this limit, a decision is again made as to whether or not this is a reject of the last type of document to be tested by the validator. The results of this decision are the same as where the lower limit comparison indicated that the data was less than the lower limit. If the comparison between the data and the upper limit indicates that the data is equal to or less than the upper limit, a decision is made as to whether or not this is the-last picture to be tested. If not, the pointer is set at the next or lower limit and at the next picture.If the last picture has been tested and in the event that a backside sensor is employed, a decision is made as to whether or not the backside sensor produced the correct indication. If not, the motor reverses to return the document to the customer and the program returns to start. If the backside sensors produces a correct test, a valid document signal for that particular type is generated, the document is cleared and stacked and the program returns to the start.

It will be seen that I have accomplished the objects of my invention. I have provided a universal document validator, which is more accurate and more reliable than are validators of the prior art. My validator may validate more than one type of document. My validator may readily be altered, so as to change the type of types of documents to be validated.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of may claims without departing from the spirit of my invention. It is, therefore, to be understood that my invention is not to be limited to the specific details shown and described.

Claims

1. Apparatus for validating documents comprising a plurality of radiation responsive elements, a source of said radiation, means for positioning a document to be validated so that radiation from said source is directed over a portion of the positioned document and thence to said elements, means for producing an indication corresponding to the number of said elements activated to a predetermined level in response to radiation from said portion of the document, means for comparing said indication with minimum and maximum limits respectively corresponding to minimum and maximum numbers of elements to be activated to said predetermined level in response to a valid document, and means responsive to said comparing means for indicating whether or not the document is valid.

2. Apparatus according to claim 1 wherein said radiation is light and said elements are photoresponsive elements.

3. Apparatus according to claim 2 further including a generally closed document path for accepting a document to be validated, and means for transporting the document along said path.

4. Apparatus according to claim 3 further including a window along said path, said light source being arranged to illuminate said window.

5. Apparatus according to any preceding claim wherein said elements are arranged in an array and a picture of a predetermined region of the document is produced in terms of the number of said activated elements.

6. Apparatus according to any preceding claim further including first storage means for storing a first number corresponding to said minimum number of said activated elements, and second storage means for storing a second number corresponding to said maximum number of said activated elements, said numbers providing said minimum and maximum limits.

7. Apparatus according to claim 6 wherein said apparatus is arranged to validate documents of two different types, further comprising third and fourth storage means for storing means for storing respectively third and fourth numbers corresponding to respectively further minimum and maximum numbers of said activated elements, whereby said first-mentioned and further minimum and maximum numbers are compared in the comparing means with said indication corresponding to the number of activated elements, and said means responsive to said comparing means indicates whether said document is a valid document of one type or of the other type or an invalid document.

8. Apparatus according to any preceding claim wherein said positioning means is arranged to successively receive and position a series of documents to be validated.

9. Apparatus according to claim 8 as dependent on claim 6 or 7 further including means for feeding information of the number of said activated elements to said storage means, means for controlling the respective minimum number storage means to register the lowest number of said elements activated upon reception of successive documents by said positioning means and for controlling the respective maximum number storage means to register the highest number of said elements activated upon reception of successive documents by said positioning means.

10. Apparatus according to any preceding claim further including position sensing means for detecting the position of a document and means responsive to the position sensing means for polling the elements so as to provide said indication corresponding to the number of said activated elements.

11. Apparatus according to claim 10 as dependent on claim 3 wherein said polling means periodically polls the elements in the course of movement of said document along said path to provide a plurality of said indications corresponding to the number of said activated elements, said comparing means being arranged to compare said indications periodically with said minimum and maximum limits.

12. Apparatus according to any preceding claim further comprising means for setting said device to operate in a validate mode, and means for setting said device in a learning mode including means responsive to said comparing means for updating said minimum and maximum limits as successive valid documents are tested.

1 3. Apparatus for validating documents substantially as hereinbefore described with reference to Figures 1 to 7 of the accompanying drawings.

14. Apparatus for validating documents constructed to operate substantially as hereinbefore described with reference to Figures 8 to 12 of the accompanying drawings.

1 5. Apparatus for validating documents including in combination, means forming a generally closed document path a window along said path, means for transporting a document to be validated along said path and past said window, a source of light for illuminating said window, an array of photosensitive elements positioned adjacent to said path to receive light from an area of said document at said window in response to illumination of said window from said source, position sensing means for detecting the position of a document moving along said path, means responsive to said position detecting means for polling the elements of said array to generate a number corresponding to the number of said elements activated to a predetermined level in response to light received from said document area, means for storing a first number corresponding to the minimum number of said elements which must be activated to said predetermined level in response to a valid document, means for storing a second number corresponding to the maximum number of said elements which should be activated to said level, means for comparing the number of elements of said array activated to said degree in response to light from said area with said first and second numbers and means responsive to said comparing means for producing an indication of whether or not said document is valid.

1 6. A device for validating documents including in combination, means forming a document transport path having an entrance and an exit, an array of a plurality of photoresponsive elements positioned adjacent to said path, means for moving a document along said path in a direction from said entrance toward said exit, a source of light, means for directing light from said source over a predetermined region of a document positioned at a predetermined location along said path and from said region to said array, means responsive to illumination of said array by light from said region for producing a picture of the region in terms of the number of said elements activated to a predetermined level upon illumination thereof, first means for storing a first number corresponding to the minimum number of said elements which must be activated to said level for document to be acceptable, second means for storing a second number corresponding to the maximum number of said elements which should be activated to said degree for an acceptable document, means for comparing the number of activated elements with said first and second stored numbers, and means responsive to said comparing means for producing an indication of the validity of the document.

1 7. A device for validating documents including in combination, means forming a document transport path having an entrance and an exit, an array of a plurality of radiation responsive elements positioned adjacent to said path, means for moving a document along said path in a direction from said entrance toward said exit, a source of radiation, means for directing radiation from said source over a predetermined region of a document positioned at a predetermined location along said path and from said region to said array, means responsive to irradiation of said array by radiation from said region for producing a picture of the region in terms of the number of said elements activated to a predetermined level, first means for storing a first number corresponding to the minimum number of said elements which must be activated to said level for a document to be acceptable, second means for storing a second number corresponding to the maximum number of said elements which should be activated to said degree for an acceptable document, means for comparing the number of activated elements with said first and second stored numbers, and means responsive to said comparing means for producing an indication of the validity of the document.

1 8. In a device for validating documents, apparatus including means for positioning a document to be validated, an array of a plurality of radiation responsive elements, a source of radiation, means for directing radiation from said source over a predetermined region of a positioned document and from said region to said array, means responsive to irradiation of said array by radiation from said region for producing a picture of the region in terms of the number of elements activated to a predetermined level, first means for storing a first number representing the minimum number of said elements which must be activated to said level for a document to be acceptable, second means for storing a second number corresponding to the maximum number of said elements which should be activated to said degree for an acceptable document, means for comparing the number of activated elements with said first and second stored numbers and means responsive to said comparing means for producing in indication of whether or not a document is valid.

1 9. In a device for validating documents of two different types, apparatus including means for positioning a document to be validated, an array of a plurality of radiation responsive elements, a source of radiation, means for directing radiation from said source over a predetermined area of a positioned document and from said area over said array, means responsive to irradiation of said array by radiation from said source for producing a picture of the area in terms of the number of elements activated to a predetermined level, first means for storing a first number representing the minimum number of said elements which must be activated to said level for a document of a first type to be acceptable, second means for storing a second number representing the minimum number of said elements which must be activated to said level for a document of a second type to be acceptable third means for storing a third number representing the maximum number of said elements which should be activated to said degree by an acceptable document of the first type, fourth means for storing a fourth number representing the maximum number of said elements which should be activated to said degree by an acceptable document of the second type, means for comparing the number of activated elements with said stored first and second and third and fourth numbers, and means responsive to said comparing means for producing an indication of whether said document is a valid document of the first type of a valid document of the second type or an invalid document.

20. In a device for validating documents, including means for receiving and for positioning a series of valid documents of the type to be validated by said device, an array of a plurality of radiation responsive elements, a source of radiation, means for directing radiation from said source over a predetermined area of a positioned document and from said area over said array, means responsive to irradiation of said array from said source for producing picture signal information of the area in terms of the number of said elements activated to said predetermined level, first storage means adapted to store a first number in response to signal information fed thereto, second storage means adapted to store a second number in response to signal information fed thereto, means for feeding picture signal information produced by successive documents received by said positioning means to said first and second storage means, means for controlling said first storage means to register the lowest number of said elements activated upon the reception of successive documents by said positioning means, and means for controlling said second storage means to register the highest number of said elements activated upon the reception of successive documents by said positioning means.

21. Apparatus for validating documents including in combination means forming a document transport path, means for transporting a document to be validated along said path, a source of radiation, means for irradiation of an area along said path with radiation from said source, an array of a plurality of radiation responsive elements positioned adjacent said path to receive radiation from the portion of a document passing over said area, means for periodically polling the elements of said array in the course of movement of said document along said path to provide a plurality of pictures of respective areas of said document in terms of the number of elements activated beyond a predetermined level in the course of each polling operation, means for storing respective maximum and minimum number limits for document areas corresponding to said pictures, means for comparing said picture information with said limits, and means responsive to said comparing means for producing an indication of whether or not said document is valid.

22. In a device for validating documents, apparatus including means for positioning a document to be validated, an array of a plurality of radiation responsive elements, a source of radiation, means for directing radiation from said source over a predetermined region of a positioned document and from said region to said array, means responsive to irradiation of said array by radiation from said region for producing a picture of the region in terms of the number of elements activated to a predetermined level, first means for storing a first number representing the minimum number of said elements which must be activated to said level for a document to be acceptable, second means for storing a second number corresponding to the maximum number of said elements which should be activated to said degree for an acceptable document, means for comparing the number of activated elements with said first and second stored numbers, means for setting said device to operate in a validate mode including means responsive to said comparing means for producing an indication of the validity of a document being tested, and means for setting said device in a learning mode including means responsive to said comparing means for updating said storing means as successive valid documents are tested.