WO2002093505A1

WO2002093505A1 - Sheet handling apparatus

Info

Publication number: WO2002093505A1
Application number: PCT/GB2002/002122
Authority: WO
Inventors: David Alan Brooks
Original assignee: De La Rue International Limited
Priority date: 2001-05-11
Filing date: 2002-05-09
Publication date: 2002-11-21
Also published as: GB0111586D0

Abstract

Sheet handling apparatus comprises an input hopper (2); one or more output hoppers (105); a transport system (15, 19, 24) for conveying sheets singly from the input hopper to the or one of the output hoppers; and a detection system (50) passed which the sheets are conveyed for detecting one or more characteristics of the sheets. A microphone (220) is arranged to respond to noise produced by a sheet as it is being bent around a roller (19) of the transport system. A control system is connected to the detection system (50) for controlling operation of the transport system. The roller (19) has a substantially constant radius so that the curvature imparted to the sheet by the roller is substantially constant along the dimension of the sheet parallel to the axis of the roller, the control system being connected to the microphone (220) to determine the stiffness of the sheet.

Description

SHEET HANDLING APPARATUS

The invention relates to sheet handling apparatus and is particularly suitable for use in handling documents of value such as banknotes .

A variety of banknote counting devices have been developed over the last few years which are able to discriminate between different denominations of banknotes using pattern recognition or size detection techniques and provide high speed counting and evaluation of mixed denomination or single denomination batches of banknotes. Examples include the De La Rue 2700 and 2800 counters. These apparatus also need to include note condition detectors. A note condition detector that has been used on large scale sorting equipment and the like determines the stiffness of sheets by detecting the noise produced by a sheet as it is being bent. This technique is described in more detail in EP-A-0073133. The problem with incorporating this technique in to banknote counters is that, as described in EP-A-0073133, a special roller or drum has been required so as to impart a lateral corrugation in the banknote while it is being bent in the feed direction. Since the banknote counting apparatus mentioned above is desirably made as small and as simple as possible, any attempt to incorporate the audio detector will increase its complexity and size and therefore cost.

In accordance with the present invention, sheet handling apparatus comprises an input hopper; one or more output hoppers; a transport system for conveying sheets singly from the input hopper to the or one of the output hoppers; a detection system passed which the sheets are conveyed for detecting one or more characteristics of the sheets; a microphone arranged to respond to noise produced by a sheet as it is being bent around a roller of the transport system; and a control system connected to the detection system for controlling operation of the transport system and is characterised in that the roller has a substantially constant radius so that the curvature imparted to the sheet by the roller is substantially constant along the dimension of the sheet parallel to the axis of the roller, the control system being connected to the microphone to determine the stiffness of the sheet.

We have found surprisingly that it is not necessary to impart a lateral corrugation to the sheet, typically a banknote, the noise generated by simply bending the sheet in the feed direction being sufficient to determine its stiffness and hence condition. This has enabled us to incorporate this condition sensing technique into simple sheet counting apparatus without having to increase the size and complexity of that apparatus.

In conventional sheet or banknote counting apparatus, there are several rollers which impart a bend on the sheets as they are conveyed by the transport system. A substantial bend is commonly caused by a roller which forms part of a separation system located adjacent the input hopper and in the preferred approach therefore the microphone is located adjacent this roller. However, other rollers such as double detect rollers could also be used.

The invention is particularly suited for use with apparatus having a single output hopper and also with apparatus having only two output hoppers . In the latter case, the transport system will include a diverter to enable the sheets to be conveyed to one or other of the output hoppers as decided by the control system.

The detection system may take a variety of forms all known in the art. For example, it could simply detect the passage of sheets to enable them to be counted. In a more sophisticated approach, the dimensions of the sheets could be monitored to confirm authenticity and/or to determine denomination. In a further alternative, the detection system could comprise an optical or other radiation scanning system for scanning the sheets as they pass to detect pattern or other characteristics of the sheets for comparison with prestored master patterns so as to identify denominations in the case of banknotes.

The control system will control the transport system in a variety of ways depending upon the form of the apparatus. If a single output hopper only is provided then the control system can arrange to stop operation of the transport system and thus further transport of the sheets to enable a sheet which does not meet the required criteria to be extracted. For example, a sheet whose denomination does not match a desired denomination or a sheet considered not to be authentic. In the case of a dual output hopper apparatus, the control system could operate a diverter of the transport system in accordance with the outcome of the detection system and stiffness data with an additional option of stopping the transport system.

Some examples of sheet handling apparatus according to the present invention will now be described with reference to the accompanying drawings, in which: -

Figure 1 is a schematic diagram showing the primary transport components of a first example;

Figure 2 is a view similar to Figure 1 but of a second example;

Figure 3 is a block diagram illustrating the processing components for either of the examples of Figures 1 and 2;

Figure 4 illustrates the noise generated by a mint banknote ; and,

Figure 5 illustrates the noise generated by a limp banknote , Figure 1 illustrates a banknote counter 100 having an input hopper 2 mounted beneath an inlet opening 3 in an enclosure 1 which comprises upper and lower parts la, lb normally screwed together. Contained within the enclosure 1 is an internal chassis assembly (not shown for clarity) which itself has side members between which the sheet feeding and transport components to be described herein, are mounted. Two conventional feed wheels 5 are non-rotatably mounted on a shaft 7, which is rotatably mounted to the chassis assembly, and have radially outwardly projecting bosses 6 which, as the feed wheels rotate, periodically protrude through slots in the base of the hopper 2.

A pair of stripper wheels 15 are non-rotatably mounted on a drive shaft 16 which is rotatably mounted in the chassis assembly. Each stripper wheel 15 has an insert 17 of rubber in its peripheral surface. Shaft 16 is driven clockwise by a motor 200 (Figure 3) to feed notes individually from the bottom of a stack of notes placed in the hopper 2.

Transversely in alignment with, and driven from the circumferential peripheral surface of the stripper wheels 15, are pressure rollers 30 which are rotatably mounted on shafts 31 spring biased towards the stripper wheels 15. Downstream of the wheels 15 is a pair of transport rollers 19 non-rotatably mounted on a shaft 20 rotatably mounted in the chassis assembly. Each roller 19 has a cylindrical form with a constant radius along its axis. Shaft 20 is driven clockwise from a second motor (not shown) to transport the note in the transport arrangement, in conjunction with pairs of pinch rollers 21,23 into stacking wheels 27 and hence output hopper 105. Pinch rollers 21, rotatably mounted on shafts 22 spring biased towards the transport rollers 19, transversely align with rollers 19 and are driven by the peripheral surface of the rollers 19. The rollers 23, rotatably mounted on shafts 24 are in alignment with the transport rollers 19, and are essentially caused to rotate by the note passing between the adjacent peripheral surfaces of the rollers 19 and 23. Situated between the pressure rollers 30 and pinch rollers 21 are separator roller pair 25, non-rotatably mounted on shaft 26 adjustably fixed to a top moulding assembly 32, having a circumferential peripheral surface which is nominally in alignment with the peripheral circumferential surface of, but transversely separated from, the stripper wheels 15.

Also forming part of the top moulding assembly 32, is a curved guide surface 8 extending partly around the circumference of the rollers 15, 19 which, when the top moulding is lifted allows the operator access to the note feed and transport path so that a note jam can be cleared. A surface 37 provides note guiding from the end of the curved guide surface 8 to the conventional stacking wheels 27.

The drive shaft 16 is continuously driven, and this, via a belt and pulley arrangement from shaft 16, causes the auxiliary drive shaft 7 rotating the feed wheel 5 also to be driven. Drive shaft 20, rotating the transport rollers 19, is driven by the other drive motor. A further pulley and belt arrangement (not shown) between shaft 20 and shaft 28, on which the stacking wheels 27 are non-rotatably mounted, provides the drive to the stacking wheels 27.

A guide plate 9 extends as a continuation of the base of the hopper 2 towards the nips formed between the transport rollers 19 and the rollers 23.

A pattern recognition system including a linear photodiode array and front end processing 50 is mounted adjacent to the transport path. The array extends across the full length of the banknotes (transverse to the feed direction) , so as to detect light originating with a light source 50A transmitted through the banknotes as they pass beneath the detector. (Other known detectors could be used which, for example, only scan a portion or portions of the banknotes.) The system 50 is coupled with a control processor 210 which samples the photodiode outputs regularly.

Sampled photodiode output signals are digitized and stored and then compared with a set of prestored images. Where the counter 100 is to count a single denomination then the prestored images will correspond to the appearance of that denomination in all possible orientations. If the counter 100 is to form a "value balancing" count of mixed currency then the prestored images will define the appearance of each currency in all its orientations .

A microphone 220 is positioned adjacent the roller 19 so as to record the noise of a note as it is bent around the roller during its passage through the counter. The microphone 220 is connected to the processor 210.

The microprocessor 210 will convert the received signals from the microphone 220 into digital form and then compare them with suitable thresholds to determine whether or not the sound heard by the microphone corresponds to a banknote of the required condition. In some cases, the sound will vary depending upon the denomination of the banknote and so in those cases, the microprocessor 210 will select a threshold appropriate to the denomination already determined via the system 50. The microphone 220 is positioned upstream of the system 50 in the example although it could be provided downstream.

The processor 210 will determine whether or not the note is of the expected denomination (in the case of single denomination counting) or one of the expected denominations

(in the case of mixed denomination counting) and also whether the stiffness sensed by the microphone corresponds to a banknote of the required condition and if these tests are satisfied will increment a count accordingly. The count will typically be a count of the total value of the notes being counted although in some cases it could simply represent the number of notes .

If the microprocessor 210 determines an unacceptable condition such as a corrupted image, an indefinable image, a note of incorrect stiffness, or the like then it will cause at least the drive motor 220 to stop so that the unacceptable note or notes will be stacked at or near the top of the stack formed in the output hopper 105 and no further notes will be drawn out of the input hopper 2. The entire stack can then be refed or the operator, in some cases, can adjust the count either to decrement it if the notes are to be removed or to increment it as necessary if the notes are, in fact, acceptable.

The counter 100 shown in Figure 1 has a single output hopper 105. The invention is also applicable, however, to counters/sorters having multiple output hoppers and Figure 2 illustrates such an example with two output hoppers. The Figure 2 counter 300 has an input hopper 401 having a base 402 with an aperture 403, through which a high friction portion 404 of a nudger wheel 405 can project, the wheel 405 being driven by a motor 200. The base 402 optionally has a second aperture 406 in alignment with a barcode reader 407 for reading data on note separators. Bank notes are supported in a stack on the base 402 against a front wall 426, and are fed intermittently by rotation of the nudger roller 405 into a nip 408, between a high friction feed roller 409 and a separator, counter rotating roller

410. The nudger 405 and roller 409 are driven by a motor 200 (not shown) . The documents pass through pinch rollers

411, 412 (the pinch roller (s) 411 having a cylindrical form) into a pattern detection region 413 in which a sensor of a transmission pattern recognition system 414A,414B (414B indicating a radiation source) scans the bank note as it is fed and passes information back to a microprocessor 210 (Figure 3) . Each bank note is then fed through pinch rollers 416, 417 onto a drive belt 418 which conveys the bank note around various rollers 419 to a diverter 420. The position of the diverter 420 is controlled by the microprocessor 210, so that bank notes are guided either towards an output pocket 421, where they are stacked using a rotating stacking wheel 422 in a conventional manner, or to a reject bin 423.

As can be seen, the bank notes are stacked on the base 402 and are urged forward against the front wall 426. A small gap 427 is provided at the base of the front wall, through which individual bank notes and separators can be nudged. A microphone 220 is located adjacent the roller 411 to pick up the noise of the notes as they are bent around the roller 411.

The pattern recognition system 414A,414B operates on the detected image data in an exactly similar way to the system 50 of the previous example. In this case, however, instead of stopping the transport when an unsatisfactory condition is determined such as a double note feed, unrecognised denomination, unsatisfactory stiffness or the like, the diverter 420 is operated by the microprocessor 210 so that the unacceptable notes are fed to the reject bin 43.

Figures 4 and 5 illustrate the manner in which the noise of a sheet being bent around the roller and picked up by the microphone 220 in any of the examples, can be used to authenticate the sheet as a valid banknote. Figure 4 illustrates that the noise of the valid, fit note being bent has a much larger intensity than that for the unfit note. Thus, by setting a suitable threshold, a valid note is only passed as fit if noise which exceeds that threshold is detected. In the same way, the threshold eliminates background noise from being misinterpreted.

Claims

1. Sheet handling apparatus comprising an input hopper; one or more output hoppers ; a transport system for conveying sheets singly from the input hopper to the or one of the output hoppers; a detection system passed which the sheets are conveyed for detecting one or more characteristics of the sheets; a microphone arranged to respond to noise produced by a sheet as it is being bent around a roller of the transport system; and a control system connected to the detection system for controlling operation of the transport system characterised in that the roller has a substantially constant radius so that the curvature imparted to the sheet by the roller is substantially constant along the dimension of the sheet parallel to the axis of the roller, the control system being connected to the microphone to determine the stiffness of the sheet.

2. Apparatus according to claim 1, wherein the roller forms part of a separation system located adjacent the input hopper so as to. receive sheets from the input hopper and feed them singly towards the detection system.

3. Apparatus according to claim 1 or claim 2, the apparatus having a single output hopper.

4. Apparatus according to claim 1 or claim 2, the apparatus having only two output hoppers, and wherein the transport system includes a diverter to enable sheets to be fed to one or other of the output hoppers .

5. Apparatus according to any of the preceding claims, wherein the detection system includes a scanning system for detecting pattern information on the sheets.

6. Apparatus according to any of the preceding claims, the control system being adapted to control the transport system in accordance with information received from one or both of the detection system and microphone.

7. Apparatus according to claim 6, wherein the sheets comprise banknotes, the control system being adapted to determine the denomination of the banknotes from information received from the detection system and to determine the fitness of the banknotes from the stiffness information.