Abstract:
A paper sheet storage device comprises paper sheet transporting units  401  to  406  having a transport path  450  for paper sheets and for transporting the paper sheets; a paper sheet feeder  250  for feeding a paper sheet onto the transport path; sensors  301  to  303,  disposed on the transport path, for detecting passage of a paper sheet; a transport speed acquiring unit for acquiring the transport speed of a paper sheet based on detection by the sensors; and a controller  210  for controlling the paper sheet transport unit and the paper sheet feeder. In the event that the acquired transport speed of a paper sheet is slower than a prescribed speed, the controller causes the paper sheet feeder to halt the feeding of paper sheets, and operates in reverse a portion of the paper sheet transport unit that is situated closer to the paper sheet feeder than the slow moving paper sheet.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority from Japanese application JP2007-236327 filed on Sep. 12, 2007, the content of which is hereby incorporated by reference into this application. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a currency bill deposit/withdrawal device such as an automated teller machine or cash dispensing machine. 
         [0004]    2. Description of the Related Art 
         [0005]    Automated teller machines and cash dispensing machines handle bulk deposits and withdrawals of currency bills. If bills should overlap as they are conveyed through an automatic teller machine or cash dispensing machine, jamming may occur. One known means for preventing this is a chain correction mechanism which varies the speed of transport depending on the spacing between individual bills detected by a sensor. In this prior art, for paper currency bills which are being transported in succession, in the event that a following bill is transported at high speed such that it begins to overtake a leading bill, the following bill will be transported at slower speed; or in the event that a leading bill is slow and begins to be overtaken by a following bill, the leading bill will be transported at faster speed. 
         [0006]    However, in the prior art discussed above, paper currency transport speed cannot be faster than the speed of the transport unit, and thus under normal circumstances it will not be possible for a following bill is transported at high speed sufficient to overtake a leading bill. On the other hand, it is possible for a following bill to overtake a leading one in the event that, for example, slipping has occurred between the leading bill and the transport unit. So in relation to speed adjustment in the same direction, there are instances in which the transport speed of the leading bill cannot be increased. Accordingly, in the prior art, it was difficult to prevent the occurrence of jamming caused when a slow leading bill is overlapped by a following bill. 
       SUMMARY OF THE INVENTION 
       [0007]    An object of the present invention is to prevent or reduce jamming caused by overlapping paper currency bills. 
         [0008]    The present invention in a first aspect provides a paper sheet storage device. The device comprises a paper sheet transport unit having a transport path for paper sheets; a paper sheet feeder for feeding the paper sheets to the transport path; a sensor, disposed on the transport path, for detecting passage of the paper sheets; a transport speed acquiring unit for acquiring the transport speed of the paper sheet based on detection by the sensor; and a controller for controlling the paper sheet transport unit and the paper sheet feeder. In the event that the acquired transport speed of a paper sheet is slower than a prescribed speed, the controller causes the paper sheet feeder to halt the feeding of paper sheets, and operates in reverse a portion of the paper sheet transport unit that is situated closer to the paper sheet feeder than the slow moving paper sheet. According to this configuration, in the case a transport speed of a leading paper sheet will become slow, a following paper sheet will run to reverse. So a gap between the leading paper sheet and the following paper sheet becomes wide, and it is possible to prevent or reduce jamming caused by overlapping paper sheets. 
         [0009]    The device may include a plurality of sensors including first and second sensors that are disposed adjacently with each other; and the transport speed acquiring unit may acquire the speed of motion of a paper sheet based on a gap between first and second sensors, and a difference between a point in time that the paper sheet passes the first sensor and another point in time that the paper sheet passes the second sensor. According to this configuration, the transport speed of the paper sheets can be determined easily. 
         [0010]    The device may include the aforementioned plurality of the sensors including first and second sensors that are disposed adjacently with each other, and may further comprise an arrival time predicting unit for predicting, from a point in time that the paper sheet passes the first sensor, arrival time of the paper sheet at the second sensor. In the event that the paper sheet fails to arrive at the second sensor within a predetermined time interval starting from the predicted arrival time, the controller causes the paper sheet feeder to halt the feed of paper sheets, and operates in reverse a portion of the paper sheet transport unit, that is situated closer to the paper sheet feeder than the first sensor. According to this configuration, delayed transport of paper sheets can be detected and jamming can be prevented before it occurs. 
         [0011]    The present invention in a second aspect provides a method of controlling a paper sheet storage device. The method comprises the steps of: feeding paper sheets from a paper sheet feeder; using a paper sheet transport unit to transport paper sheets; using a sensor to detect passage of a paper sheet; determining the transport speed of the paper sheet from the paper sheet passage time; and in the event that the transport speed of a paper sheet is slower than a prescribed transport speed, halting the feed of paper sheets from the paper sheet feeder, and then reverse-feeding the following paper sheets to return to the paper sheet feeder. According to this aspect, jamming caused by overlapping paper sheets can be prevented before it occurs. 
         [0012]    The present invention in a third aspect provides a control program, stored on a computer readable medium, for a paper sheet storage device. The program accomplishes the functions of feeding paper sheets; transporting paper sheets; detecting passage of a paper sheet; determining the transport speed of the paper sheet from the passage time of the paper sheet; and in the event that the determined transport speed of a paper sheet is slower than a prescribed transport speed, halting feed of paper sheets by the paper sheet feeder, and then reverse-feeding the following paper sheets by the paper sheet transport unit to return to the paper sheet in the paper sheet feeder. According to this aspect, jamming caused by overlapping paper sheets can be prevented before it occurs. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    Preferred embodiments of the present invention will now be described in conjunction with the accompanying drawings, in which: 
           [0014]      FIG. 1  is an illustration depicting schematically the appearance of an ATM pertaining to Embodiment 1. 
           [0015]      FIG. 2  is an illustration depicting schematically the block configuration of an ATM pertaining to Embodiment 1. 
           [0016]      FIG. 3  is an illustration showing the control block of a paper currency handling unit  200 . 
           [0017]      FIG. 4  is an illustration depicting schematically the internal configuration of a paper currency handling unit  200 . 
           [0018]      FIG. 5  is a flowchart depicting operation of an ATM  10  when making a deposit. 
           [0019]      FIG. 6  is a flowchart depicting operation of an ATM  10  when making a withdrawal. 
           [0020]      FIG. 7  is an illustration showing in detail a path leading from a paper currency accepting/dispensing unit  250  to a paper currency discriminating unit  260 . 
           [0021]      FIG. 8  is a flowchart depicting transport control of paper currency. 
           [0022]      FIG. 9  is a flowchart depicting transport control of paper currency in a Modification Example. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    The configuration of an automated teller machine (hereinafter “ATM”) pertaining to Embodiment 1 will be described with reference to  FIGS. 1 and 2 .  FIG. 1  is an illustration depicting schematically the appearance of an ATM pertaining to Embodiment 1.  FIG. 2  is an illustration depicting schematically the block configuration of the ATM pertaining to Embodiment 1. The ATM  10  includes a main controller  100 , a card/statement processor  110 , a touch panel  120 , an administrator operation unit  130 , a network interface  140 , and a paper currency handling unit  200 , which are interconnected through an internal bus  150 . 
         [0024]    The main controller  100  controls the card/statement processor  110 , the touch panel  120 , the administrator operation unit  130 , the network interface  140 , and the paper currency handling unit  200 . The card/statement processor  110  includes a passbook printer  112  and a reader/writer  114 . The passbook printer  112  performs printing of transaction records or printing of passbook entries. The reader/writer  114  performs reading of data from or writing of data to a card. 
         [0025]    The touch panel  120  detects input from a customer. Here, “customer input” refers to an instruction to make a deposit or a withdrawal, for example. The detected input is transmitted from the touch panel  120  to the main controller  100 . The touch panel  120  has both an input detection function and a display function; it both detects customer input and displays messages from the ATM  10  to the customer. The administrator operation unit  130  detects operations performed by an administrator employee of the financial institution. The network interface  140  connects the ATM  10  to a network  20 . The ATM  10  is connected to a host computer (not shown) via the network  20 . 
         [0026]    The paper currency handling unit  200  performs discrimination of paper currency bills which have been deposited to the ATM  10 , and transmits the discrimination results to the main controller  100  as well as sorting the paper currency bills and placing them in an internal repository. Upon receiving an instruction from the main controller  100 , the paper currency handling unit  200  will retrieve and dispense paper currency bills from the internal repository. The paper currency handling unit  200  has both a paper currency accepting/dispensing unit  250  for accepting and dispensing paper currency, and a coin accepting/dispensing unit  252  for accepting and dispensing coins. 
         [0027]    The paper currency handling unit  200  will be described making reference to  FIGS. 3 and 4 .  FIG. 3  is an illustration showing the control block of the paper currency handling unit  200 .  FIG. 4  is an illustration depicting schematically the internal configuration of the paper currency handling unit  200 . 
         [0028]    The control block of the paper currency handling unit  200  includes a CPU  210  and a memory  220  which are interconnected by an internal bus  240 . The paper currency handling unit  200  is provided internally with a paper currency discriminating unit  260 , a paper currency escrow repository  270 , a counterfeit bill repository  272 , a walk-away recovery repository  274 , a paper currency recovery repository  276 , recycling repositories  278   a  to  278   e,  paper currency transport devices  301  to  322 , and switching gates  401  to  410 . 
         [0029]    The paper currency discriminating unit  260  scans the currency bills and acquires currency data for the purpose of discerning the genuineness and denomination of the currency bills. In the present embodiment, determination of genuineness and denomination of currency bills is carried out through execution by the CPU  210 , discussed later, of a paper currency discrimination program  224 , discussed later, and processing of the currency data acquired by the paper currency discriminating unit  260 . The paper currency escrow repository  270  provides temporary storage of genuine currency bills. The counterfeit bill repository  272  stores any counterfeit bills. The walk-away recovery repository  274  will store any currency bills that a customer has forgotten to retrieve when cash is dispensed or returned. The paper currency recovery repository  276  stores currency bills which are genuine but damaged to the point of being unsuitable for recirculation. The recycling repositories  278   a  through  278   e  store currency bills which are genuine and suitable for recirculation. In the present embodiment, five recycling repositories  278   a  through  278   e  are provided in association with different denominations. It would be acceptable to provide two or more of recycling repositories  278   a  through  278   e  for a single denomination. Where recycling repositories  278   a  through  278   e  are not distinguished in this way, they will be denoted as recycling repositories  278 . For security purposes the paper currency recovery repository  276  and the recycling repositories  278  are located within a safe  280 . 
         [0030]    The paper currency transport devices  301  to  322  are transport devices for transporting currency bills. In the present embodiment, the paper currency transport devices  301  to  322  use belts or rollers for example to transport the currency bills. The switching gates  401  to  410  are gates for switching the transport direction of currency bills. The switching gates  401  to  410  have transport devices in three or four directions, and will shunt a paper currency bill transported from one of these directions into any of the remaining two or three directions. 
         [0031]    The placement of the paper currency transport devices  301  to  322  and the switching gates  401  to  410  will be described with reference to  FIG. 4 . The paper currency transport device  301 , the switching gate  401 , the paper currency transport device  302 , the switching gate  402 , and the paper currency transport device  303  are situated between the paper currency accepting/dispensing unit  250  and the paper currency discriminating unit  260 . The paper currency transport device  304 , the switching gate  403 , and the paper currency transport device  305  are situated between the paper currency discriminating unit  260  and the paper currency escrow repository  270 . The paper currency transport device  306 , the switching gate  404 , and the paper currency transport device  307  are situated between the switching gate  403  and the paper currency accepting/dispensing unit  250 . The paper currency transport device  311  is situated between the switching gate  402  and the switching gate  404 . The paper currency transport device  308 , the switching gate  405 , and the paper currency transport device  309  are situated between the switching gate  403  and the counterfeit bill repository  272 . The paper currency transport device  310  is situated between the switching gate  405  and the walk-away recovery repository  274 . 
         [0032]    The paper currency transport device  312 , the switching gate  406 , the paper currency transport device  313 , the switching gate  407 , the paper currency transport device  314 , the switching gate  408 , the paper currency transport device  315 , the switching gate  409 , the paper currency transport device  316 , the switching gate  410 , and the paper currency transport device  317  are situated between the switching gate  401  and the paper currency recovery repository  276 . The paper currency transport devices  318  through  322  are situated respectively between the switching gates  406  through  410  and the recycling repositories  278   a - e.    
         [0033]    The CPU  210  controls the operation of the paper currency accepting/dispensing unit  250 , the paper currency discriminating unit  260 , the paper currency escrow repository  270 , the counterfeit bill repository  272 , the walk-away recovery repository  274 , the paper currency recovery repository  276 , the recycling repositories  278 , the paper currency transport devices  301  to  322 , and the switching gates  401  to  410 . The memory  220  has stored in memory therein a paper currency feed control program  222 , the paper currency discrimination program  224 , a transport speed acquisition program  226 , a paper currency arrival time prediction program  228 , a paper currency transport control program  230 , and a switching gate control program  232 . 
         [0034]    In the event that, for example, slowed transport speed of a currency bill has been detected, the paper currency feed control program  222  will perform control of feed of the currency bills by halting the feed of currency bills from the paper currency accepting/dispensing unit  250 , the paper currency escrow repository  270 , the recycling repositories  278 , and so on. The paper currency discrimination program  224  uses the currency bill data acquired from currency bills by the paper currency discriminating unit  260  to determine the genuineness and denomination of the currency bills. The transport speed acquisition program  226  uses the point in time that a currency bill arrived at a sensor (discussed later), which has been recorded in the memory  220 , and the distance between sensors, which is stored in memory  220 , to determine the transport speed of the currency bill. The paper currency arrival time prediction program  228  uses the time of arrival at a given sensor to predict the time of arrival at the next sensor. In general, when calculating the transport speed of a currency bill it will be necessary for the bill to pass sensors at two locations. However, if a currency bill fails to reach the next sensor within a prescribed time interval from the time at which it passed the first sensor, it can be detected that the currency bill transport speed has been slowed, even if the actual transport speed of the bill is not known. The paper currency transport control program  230  controls operations of the paper currency transport device  301  through  322 . For example, if slow transport speed is detected, it will control a prescribed paper currency transport device so as to reverse its direction of rotation. The switching gate control program  232  controls the direction of shunting of transported paper currency in the switching gates  401  through  410 . 
         [0035]    The operation of the ATM  10  will be described below with reference to  FIGS. 5 and 6 .  FIG. 5  is a flowchart depicting operation of an ATM  10  when making a deposit.  FIG. 6  is a flowchart depicting operation of an ATM  10  when making a withdrawal. Here, typical operations during an ATM  10  deposit and withdrawal will be described; the paper currency transport control which is a particular feature of the present embodiment will be discussed later. 
       Deposit Operation 
       [0036]    When an instruction to initiate a deposit is made on the touch panel  120  by the user, the main controller  100  will open the door of the paper currency accepting/dispensing unit  250  and wait for currency bills to be placed in the paper currency accepting/dispensing unit  250  (Step S 100 ). Upon receiving an instruction from the main controller  100 , the CPU  210  will switch the switching gates  401 ,  402  so that the currency bills are transported from the paper currency accepting/dispensing unit  250  to the paper currency discriminating unit  260 , and will then drive the paper currency transport devices  301  to  303  to feed the currency bills to the paper currency discriminating unit  260 , acquire paper currency data from the paper currency discriminating unit  260 , and determine the genuineness and denomination of the currency bills (Step S 110 ). In the event that a currency bill is found to be genuine, the CPU  210  will record the denomination in the memory  220 , switch the switching gate  403  so that the bill is transported to the paper currency escrow repository  270 , and drive the paper currency transport devices  304 ,  305  to transport the bill to the paper currency escrow repository  270 . In the event that a currency bill is found to be counterfeit, the CPU  210  will switch the switching gates  403 ,  405  so that the bill is transported to the counterfeit bill repository  272 , and drive the paper currency transport devices  304 ,  308 , and  309  to transport the bill to counterfeit bill repository  272  (Step S 120 ). 
         [0037]    The main controller  100  will then display on the touch panel  120  the total amount of the denominations of the deposited paper currency (Step S 130 ), and will wait for an instruction from the user. In the event that user input of an instruction to proceed with the deposit is detected (Step S 140 : Yes), the main controller  100  will instruct the paper currency handling unit  200  to transport the currency bills to the paper currency recovery repository  276  and the recycling repositories  278  (Step S 150 ). Specifically, upon receiving an instruction from the main controller  100 , the CPU  210  will switch the switching gate  403  so that the currency bills are transported to the paper currency discriminating unit  260 , and drive the paper currency transport devices  305 ,  304  to transport the bills to the paper currency discriminating unit  260 . The CPU  210  will then acquire the currency bill data from the paper currency discriminating unit  260  and re-check the paper currency denominations. On the basis of the paper currency denominations the CPU  210  will determine whether to transport the bills to the paper currency recovery repository  276  or the recycling repositories  278   a - e,  and perform the appropriate switching of the switching gates  402 ,  401 , and  406  through  410 . The CPU  210  will then drive the paper currency transport devices  303 ,  302 , and  312  through  322  to transport the bills to their determined transport destinations. 
         [0038]    In the event that user input of an instruction to cancel the deposit is detected (Step S 140 : No), the main controller  100  will instruct the paper currency handling unit  200  to transport the paper currency to the paper currency accepting/dispensing unit  250  (Step S 160 ) and return the bills to the user. Specifically, upon receiving an instruction from the main controller  100 , the CPU  210  will switch the switching gates  403 ,  404  so that the currency bills are transported to the paper currency accepting/dispensing unit  250 , and then drive the paper currency transport devices  305  through  307  to transport the bills to the paper currency accepting/dispensing unit  250 . 
       Withdrawal Operation 
       [0039]    When a withdrawal instruction is made on the touch panel  120  by the user (Step S 200 ), the main controller  100  will detect this, and instruct the paper currency handling unit  200  to transport paper currency to the paper currency accepting/dispensing unit  250 . 
         [0040]    Upon receiving an instruction from the main controller  100 , the CPU  210  will determine from which of the recycling repositories  278   a - e  to withdraw currency bills, and will switch the switching gates  406  through  410 ,  401 , and  402  so that the bills are transported from the prescribed recycling repositories  278   a - e  to the paper currency discriminating portion unit. The CPU  210  will then drive the paper currency transport devices  318  to  322 ,  312  to  316 ,  302 , and  303  to convey the bills to the paper currency discriminating unit  260 , where their denominations will be determined (Step S 210 ). In the event that the currency bill denominations were correct (Step S 220 : Yes), the CPU  210  will switch the switching gates  403 ,  404  so that the bills are transported to the paper currency accepting/dispensing unit  250 , drive the paper currency transport devices  304 ,  306 ,  307 , and transport the bills to the paper currency accepting/dispensing unit  250  (Step S 230 ). Once all of the bills for withdrawal have been transported to the paper currency accepting/dispensing unit  250 , the CPU  210  will dispense the bills to the user. In the event that a currency bill denomination is not correct (Step S 220 : No), the CPU  210  will switch the switching gate  403  so that the bill is transported to the paper currency escrow repository  270 , and drive the paper currency transport devices  304 ,  305  to transport the bill to the paper currency escrow repository  270 . Once the cash dispensing operation to the user has been completed, the main controller  100  will now transport bills that were transported to the paper currency escrow repository  270  to the paper currency recovery repository  276  and the recycling repositories  278  (the recycling repositories  278   a - e ) (Step S 240 ). This operation is identical to the operation of transporting bills from the paper currency escrow repository  270  to the paper currency recovery repository  276  and the recycling repositories  278  during a deposit, and will not be described. 
         [0041]    The sensors will now be described, taking the example of the path from the paper currency accepting/dispensing unit  250  to the paper currency discriminating unit  260 .  FIG. 7  is an illustration showing in detail the path leading from the paper currency accepting/dispensing unit  250  to the paper currency discriminating unit  260 . In the present embodiment, a paper currency transport path  350  is formed by the paper currency transport devices  301  to  303  between the paper currency accepting/dispensing unit  250  and the paper currency discriminating unit  260 ; and sensors  501  to  503  are positioned along the paper currency transport path  350 . The sensors  501  to  503  are respectively composed of light-emitting elements  501   a  to  503   a,  and photoreceptor elements  501   b  to  503   b.  In the present embodiment, the sensors  501  to  503  are transmission type sensors in which the light-emitting elements  501   a  to  503   a  and the photoreceptor elements  501   b  to  503   b  are disposed to either side of the paper currency transport path  350 ; however, it would also be acceptable to use reflection type sensors in which the light-emitting elements  501   a  to  503   a  and the photoreceptor elements  501   b  to  503   b  are disposed to the same side of the paper currency transport path  350 . Since the signals from the photoreceptor elements will change as currency bills block the light between the light-emitting elements and the photoreceptor elements, the CPU  210  will detect passage of bills by reading the values of the signals from the photoreceptor elements. In the present embodiment, three sensors have been provided between the paper currency accepting/dispensing unit  250  to the paper currency discriminating unit  260 , but the number of sensors is not limited to three, and may be a different number. 
         [0042]    Control of paper currency transport during deposit operations will now be described in more detail, taking the example of the path from the paper currency accepting/dispensing unit  250  to the paper currency discriminating unit  260 .  FIG. 8  is a flowchart depicting transport control of paper currency. When currency bills are deposited, they will be fed one at a time to the paper currency transport path  350  from the paper currency accepting/dispensing unit  250 . The bills will then be transported by the paper currency transport device  301 , and as they pass the location of the sensor  501  the value of the signal from the sensor  501  will change, whereby the CPU  210  will detect arrival of the bills at the sensor  501  (Step S 300 ). The CPU  210  will record the time t 1  of arrival of a bill at the sensor  501  in the memory  220  (Step S 305 ). The bill will then be transported forward by the paper currency transport devices  301 ,  302 . When a bill reaches the location of the sensor  502 , the signal from the sensor  502  will change, whereby the CPU  210  will detect arrival of bills at the sensor  502  (Step S 310 ). The CPU  210  will record the time t 2  of arrival of the bill at the sensor  502  in the memory  220  (Step S 315 ). 
         [0043]    Since the distance between the sensor  501  and the sensor  502  has been pre-stored in the memory  220 , the CPU  210  will be able to calculate the currency bill transport speed from the distance between the sensor  501  and the sensor  502 , and the difference between the time t 1  of arrival of a bill at the sensor  501  and the time t 2  of arrival of the bill at the sensor  502  (Step S 320 ). In the event that the calculated transport speed is smaller than a prescribed value (Step S 325 : Yes), the CPU  210  will halt feed of the bill from the paper currency accepting/dispensing unit  250  and rotate the paper currency transport device  301  backward in order to reverse the subsequently dispensed bill (hereinafter termed the “following bill”; in association therewith, the corresponding bill transported at slow speed at this time is termed the “leading bill.”) back into the paper currency accepting/dispensing unit  250  (Step S 330 ). 
         [0044]    The currency bill will then be transported forward by the paper currency transport devices  302 ,  303 . When a bill reaches the location of the sensor  503 , the signal from the sensor  503  will change, and thus the CPU  210  can detect that the bill has reached the sensor  503  (Step S 335 ). The CPU  210  will record the time t 3  of arrival of the bill at the sensor  503  in the memory  220  (Step S 340 ). 
         [0045]    Since the distance between the sensor  502  and the sensor  503  has been pre-stored in the memory  220 , the CPU  210  will be able to calculate the currency bill transport speed from the distance between the sensor  502  and the sensor  503 , and the difference between the time t 2  of arrival of the bill at the sensor  502  and the time t 3  of arrival of the bill at the sensor  503  (Step S 345 ). In the event that the calculated transport speed is smaller than a prescribed value (Step S 350 : Yes), the CPU  210  will halt feed of the bill from the paper currency accepting/dispensing unit  250  and rotate the paper currency transport devices  301 ,  302  in backward in order to reverse the following bill back into the paper currency accepting/dispensing unit  250  (Step S 330 ). 
         [0046]    In the preceding description, only control on the path leading up to the paper currency discriminating unit  260  was described; however, control on the path between the paper currency discriminating unit  260  and the paper currency escrow repository  270  would be carried out analogously. The CPU  210  will calculate the transport speed of currency bills from the distance between two adjacent sensors and the difference in arrival times, and in the event it detects a bill moving at transport speed slower than a prescribed transport speed, it will rotate in reverse the paper currency transport devices situated between the bill traveling at slow speed and the paper currency accepting/dispensing unit  250 . 
         [0047]    Through this control, following bills will be returned to and stored in the paper currency accepting/dispensing unit  250 , while transport of the leading bill will continue uninterrupted. In the event that the leading bill is stored at its storage destination, for example, in the paper currency escrow repository  270 , the CPU  210  will again dispense bills from the paper currency accepting/dispensing unit  250 , rotating the paper currency transport devices in the normal direction. The reason is that since the leading is in storage, there is no risk of overlap. It is not necessary that all of the following bills be returned to the paper currency accepting/dispensing unit  250  at this time. Subsequent operation will proceed analogously to the operation described above. In the event that the leading bill fails to be stored in the paper currency escrow repository  270  within a prescribed time period, the CPU  210  will for example issue an alert to financial institution service personnel to request repair of the ATM  10 . If jamming occurs due to overlapping bills, depending on the condition of the jam, recovery may be difficult; according to the present embodiment, however, leading bills will be conveyed forward while following bills will be conveyed backward, thus avoiding jams caused by overlap. Accordingly, it will be easier for service personnel to repair the ATM  10 . 
         [0048]    Verification of transport speed will be carried out for all paper currency bills which are fed from the paper currency accepting/dispensing unit  250 . For example, if the CPU  210  has detected that the third bill (leading bill) which was fed is being transported at slow speed, it will perform control such that the paper currency transport device reached by the fourth bill (following bill), as well as the paper currency transport device lying towards the paper currency accepting/dispensing unit  250  side of this device, now rotate in reverse. 
         [0049]    In the preceding discussion, transport of bills from the paper currency accepting/dispensing unit  250  to the paper currency escrow repository  270  during deposit was described taking the example of the path from the paper currency accepting/dispensing unit  250  to the paper currency discriminating unit  260 ; however, the process would be similar in the case of transport of bills from the paper currency escrow repository  270  to the a paper currency recovery repository  276  or to the recycling repositories  278  for the purpose of storage, or of transport of bills from the paper currency escrow repository  270  to the paper currency accepting/dispensing unit  250  for the purpose of returning cash. Since description of these identical processes would be redundant they will not be described here. The process of transporting bills from the recycling repositories  278  to the paper currency accepting/dispensing unit  250  during withdrawal is also analogous to the above. Specifically, if the CPU  210  detects slow transport speed from a sensor signal, it will halt the feed of the bills, and perform control to rotate in reverse the paper currency transport device which is situated towards the feed side from the bill which was detected to be transported at slow speed. 
         [0050]    According to the embodiment above, if the CPU  210  detects a bill transported at slow speed, it will perform control to rotate in reverse the paper currency transport device which is situated towards the feed side from the detected bill, thereby preventing the leading bill and the following bill from overlapping and causing jamming. 
       MODIFICATION EXAMPLE 
       [0051]    The Modification Example will be described below with reference to  FIG. 9 .  FIG. 9  is a flowchart depicting transport control of paper currency in a Modification Example. The configuration of the Modification Example is the same as the configuration of the embodiment, so the configuration will not be discussed. 
         [0052]    Currency bills are fed one at time from the paper currency accepting/dispensing unit  250  to the paper currency transport path  350 . The bills will then be transported by the paper currency transport device  301 . As a bill passes the location of the sensor  501 , the value of the signal from the sensor  501  will change, whereby the CPU  210  will detect the arrival of the bill at the sensor  501  (Step S 400 ). The CPU  210  will record the time t 1  of arrival of the bill at the sensor  501  in the memory  220  (Step S 405 ). 
         [0053]    The CPU  210  will then predict the time at which the bill will reach the sensor  502  (Step S 410 ) and record this value to the memory  220  (Step S 415 ). The distance between the sensor  501  and the sensor  502  is a known value, and since the transport speed by the paper currency transport devices  301 ,  302  is also known, if the time t 1  of arrival of a bill at the sensor  501  is known it will be a simple matter to predict the time of arrival t 2   a  at the sensor  502 . 
         [0054]    The CPU  210  will then wait for the bill to reach the sensor  502  (Step S 420 ). If before the bill reaches the sensor  502  (Step S 420 : No) the elapsed time has passed t 2   a  (Step S 425 : Yes), the CPU  210  will detect that delayed transport of the bill has occurred (Step S 430 ). The CPU  210  will then halt the feed of bills from the paper currency accepting/dispensing unit  250  and reverse the following bills back into the paper currency accepting/dispensing unit  250  (Step S 435 ). Specifically, the CPU  210  will rotate the paper currency transport device  301  in reverse. 
         [0055]    If the CPU  210  detects that the bill has reached the sensor  502  (Step S 420 : Yes), it will record the time t 2  of arrival of the bill at the sensor  502  in the memory  220  (Step S 440 ). The CPU  201  will then predict the time at which the bill will reach the sensor  503  (Step S 445 ), and record this value to the memory  220  (Step S 450 ). The distance between the sensor  502  and the sensor  503  is a known value, and since the transport speed by the paper currency transport devices  302 ,  303  is also known, if the time t 2  of arrival of a bill at the sensor  502  is known it will be a simple matter to predict the time of arrival t 3   a  at the sensor  503 . 
         [0056]    The CPU  210  will then wait for the bill to reach the sensor  503  (Step S 455 ). If before the bill reaches the sensor  503  (Step S 455 : No) the elapsed time has passed t 3   a  (Step S 460 : Yes), the CPU  210  will detect that delayed transport of the bill has occurred (Step S 430 ). The CPU  210  will then halt the feed of bills from the paper currency accepting/dispensing unit  250  and reverse the following bills back into the paper currency accepting/dispensing unit  250  (Step S 435 ). Specifically, the CPU  210  will rotate the paper currency transport devices  301 ,  302  in reverse. 
         [0057]    If the CPU  210  detects that the bill has reached the sensor  503  (Step S 455 : Yes), it will record the time t 3  of arrival of the bill at the sensor  503  in the memory  220  (Step S 465 ). The time t 3  will be used to predict the time t 4   a  of arrival of the bill at the next sensor. The subsequent process is a repeat of the above and will not be described. 
         [0058]    According to the Modification Example, the CPU  210  can detect delayed transport of currency bills even before a bill reaches the next sensor. Accordingly, it will be possible to prevent jamming caused by overlapping paper currency bills in the event that, for example, the transport speed of a bill slows markedly for some reason during transport, or where it ceases to move at all. 
         [0059]    In the preceding embodiment, if transport delay of a leading bill is detected, the CPU  210  will carry out control in such a way as to reverse the rotation of the paper currency transport devices so that the following bill will be conveyed in the reverse direction. However, it would also be possible, for example, to slow down the rotation speed of the paper currency transport devices so that the transport speed of the following bill becomes slower than the transport speed of the leading bill. 
         [0060]    In the preceding description, there was no particular discussion of the spacing between currency bills as they are fed, but the CPU  210  may wait until a fed bill has reached the initial sensor  501  before feeding the next bill. This can prevent jamming caused by overlap of bills before reaching the initial sensor  501 . The CPU  210  may also feed and control the transport of bills in such a way that two or more bills will never be present between neighboring sensors. This can prevent jamming caused by overlapping bills. 
         [0061]    In the embodiment, sensors are positioned midway along the paper currency transport devices, but the sensors could instead be positioned between two neighboring paper currency transport devices. Since currency bill transport speed can be changed in before or after sensors, jamming caused by overlapping bills can be prevented. 
         [0062]    With regard to sensors, the embodiment and the Modification Example described three sensors positioned between the paper currency accepting/dispensing unit  250  and the paper currency discriminating unit  260 ; however, it would be possible for example to position multiple sensors on other paper currency transport paths, such as that between the paper currency discriminating unit  260  to the paper currency escrow repository  270 , that between the paper currency escrow repository  270  and the paper currency accepting/dispensing unit  250 , or that between the paper currency escrow repository  270  and the paper currency recovery repository  276  or the recycling repositories  278 . 
         [0063]    In the embodiment, a leading bill transported at slow speed will continue be transported forward, but it would be possible for the leading bill to be returned to the feed source as well. When returning bills to the feed source, return may take place at a slower transport speed than normal. 
         [0064]    While the invention has been shown herein based on certain preferred embodiments, the embodiments of the invention set forth herein are intended to facilitate understanding of the invention and should not be construed as limiting of the invention in any way. The intention is to cover all modifications and improvements falling within the spirit and scope of the invention as defined by the appended claims.