Patent Publication Number: US-8973916-B2

Title: Medium accumulating device with accumulation table detector

Description:
TECHNICAL FIELD 
     The present invention relates to a medium accumulating device and, for example, a medium accumulating device advantageously applied to automatic transaction devices disposed in financial facilities. 
     BACKGROUND ART 
     In recent years, automatic transaction devices typified by automated teller machines (ATM) in financial facilities have been installed in various sites such as banks, station premises and convenience stores. Customers can make various operations on the display screen displayed on an automatic transaction device under a variety of situations to make transactions including making money deposit and withdraw and inquiring balances. 
     Such an automatic transaction device is provided with a bill storing/discharging depository that stores and discharges bills. A bill accumulating mechanism in the conventional bill storing/discharging depository is generally provided with a transfer path such that bills are transferred onto a bill accumulation table in the horizontal direction. The bills transferred over the transfer path in the horizontal direction are vertically accumulated on the bill accumulation table in the horizontal position thereof. 
     Japanese Patent Laid-Open Publication No. 2010-128536 proposes a bill accumulating mechanism in which a bill accumulation table has an inclined surface provided, on which bills will be accumulated in the inclined position thereof. The accumulation of bills in the inclined position allows the length of the bill storage in the direction of the width of bills to be shorter than the length of a side of the bills in the direction of transferring the bills, thereby reducing the thickness of the bill storage. 
     In the bill accumulating mechanism according to the conventional art, the stage, i.e. accumulation table, for accumulating bills thereon is vertically moved by means of a driving belt or spring. Therefore, in order to detect whether or not a bill is put on the accumulation table, it is necessary to provide an assembly of light emitter-optical sensor that forms an optical path in the same direction as the moving direction of the accumulation table such that a bill can be sensed whatever position the accumulation table may occupy. 
     However, if the accumulation table is adapted for moving a longer distance, the light emitter and optical sensor are separated accordingly by a longer distance, which requires an expensive, higher-sensitive sensor, resulting in an increase in costs. By contrast, if the optical sensor is provided so as to form its optical path in a direction different from the moving direction of the accumulation table, it does not require such a longer distance between the light emitter and the optical sensor that accords to the moving distance of the accumulation table. However, the accumulation table may take its position such that the accumulation table does not interfere with the optical path of the sensor, thus the sensor failing to sense the accumulation table, which is a disadvantage. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a new and improved medium accumulating device. 
     It is another object of the present invention to provide a medium accumulating device with a simple configuration, which can determine whether or not a medium such as a bill is accumulated on an accumulation table whatever position the accumulation table may occupy. 
     In accordance with the present invention, a medium accumulating device includes an accumulation table having a surface at least partially supporting an accumulated medium, an elastic member movably supporting the accumulation table in an accumulating direction of the medium, and an accumulation table detector detecting lowering of the accumulation table. 
     In that case, the accumulation table detector may be configured to detect whether or not the accumulation table lowers below a predetermined position. 
     The accumulation table may have a surface inclined with respect to a lifting and lowering direction of the accumulation table. 
     The medium accumulating device may further include a medium detector that can detect whether or not the medium is accumulated on the accumulation table when the accumulation table is located above the predetermined position. In that case, the medium accumulating device may further include a determiner using a detection result of the accumulation table detector and a detection result of the medium detector to determine whether or not the medium is accumulated on the accumulation table. In that case further, the determiner may be configured to determine that the medium is accumulated on the accumulation table when the accumulation table lowers below the predetermined position or it is detected that the medium is accumulated on the accumulation table. 
     The determiner may be configured to determine that no medium is accumulated when the accumulation table is located above the predetermined position and it is detected that no medium is accumulated on the accumulation table. 
     The accumulation table detector may include a first set of light-emitter and optical sensor that form an optical path in a direction intersecting the lifting and lowering direction of the accumulation table, and the medium detector may include a second set of light-emitter and optical sensor that form an optical path in the direction intersecting the lifting and lowering direction of the accumulation table. In that case, the accumulation table detector and the medium detector may be provided on one side with respect to the accumulation table, and the medium accumulating device may further include a first light-guiding member guiding a first optical path to the optical sensor of the first set, and a second light-guiding member guiding a second optical path to the optical sensor of the second set. 
     The accumulation table may include a light-blocking member blocking the first optical path when the accumulation table is located above the predetermined position. 
     The accumulation table may include a light-guiding member guiding a first optical path to the optical sensor of the first set when the accumulation table is located above the predetermined position. 
     The accumulation table detector may include a set of light-emitter and optical sensor that form an optical path in a direction intersecting a lifting and lowering direction of the accumulation table, and the medium accumulating device may include a light-blocking member lowering to a position where the light-blocking member blocks the optical path as the accumulation table lowers. In that case, the accumulation table detector may be configured to detect whether or not the optical path passes a medium accumulating area of the accumulation table and the medium is accumulated on the accumulation table. 
     The medium accumulating device may further include a determiner using a detection result of the accumulation table detector to determine whether or not a medium is accumulated on the accumulation table. 
     According to the present invention, it is possible to provide a medium accumulating device which is simpler in configuration and capable of determining whether or not media such as bills are accumulated whatever position the accumulation table may occupy. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects and features of the present invention will become more apparent from consideration of the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a schematic perspective appearance view of an automatic transaction device in accordance with an embodiment of the present invention; 
         FIG. 2  is a functional block diagram schematically showing the configuration of the automatic transaction device in accordance with the embodiment of the present invention shown in  FIG. 1 ; 
         FIG. 3  is a schematic functional block diagram showing the configuration of a bill inlet/outlet port in accordance with the embodiment shown in  FIG. 2 ; 
         FIGS. 4A and 4B  are schematic vertical sectional views showing the configuration of a reject cassette in accordance with Comparative Example 1; 
         FIGS. 5A and 5B  are schematic vertical sectional views showing the configuration of a reject cassette in accordance with Comparative Example 2; 
         FIGS. 6A and 6B  are schematic vertical sectional views showing the configuration of a reject cassette in accordance with Comparative Example 3; 
         FIGS. 7A and 7B  are schematic vertical sectional views showing the configuration of a reject cassette in accordance with Comparative Example 4; 
         FIGS. 8A and 8B  are schematic vertical sectional views showing the configuration of a reject cassette in accordance with Comparative Example 5; 
         FIG. 9  is a schematic vertical sectional view showing the configuration of a reject cassette in accordance with Comparative Example 6; 
         FIG. 10  is a schematic vertical sectional view showing the configuration of a reject cassette in accordance with the first embodiment of the present invention; 
         FIGS. 11A ,  11 B and  11 C are schematic vertical sectional views showing a state transition during accumulation of bills in the reject cassette shown in  FIG. 10 ; 
         FIG. 12  is a schematic perspective view showing the reject cassette shown in  FIG. 10 ; 
         FIG. 13  is a schematic perspective view showing a state where bills are accumulated in the reject cassette shown in  FIG. 10 ; 
         FIG. 14  shows a combination of logics of sensing results of sensors in the first embodiment for use in a determiner determining whether or not bills are accumulated; 
         FIG. 15  is a schematic vertical sectional view showing the configuration of a reject cassette in accordance with the second embodiment of the present invention; 
         FIGS. 16A ,  16 B and  16 C are schematic vertical sectional views showing a state transition during accumulation of bills in the reject cassette shown in  FIG. 15 ; 
         FIG. 17  is a schematic perspective view showing the reject cassette in a case where an additional bill sensor is arranged in the embodiment shown in  FIG. 15 ; 
         FIG. 18  is a schematic perspective view showing a state where bills are accumulated in the reject cassette shown in  FIG. 17 ; 
         FIG. 19  is a schematic vertical sectional view showing the configuration of a reject cassette in accordance with the third embodiment of the present invention; 
         FIGS. 20A ,  20 B and  20 C are schematic vertical sectional views showing a state transition during accumulation of bills in the reject cassette shown in  FIG. 19 ; 
         FIG. 21  is a schematic perspective view showing the reject cassette shown in  FIG. 19 ; 
         FIG. 22  is a schematic vertical sectional view showing the configuration of a reject cassette in accordance with the fourth embodiment of the present invention; 
         FIG. 23  is a diagrammatic elevation view showing bills accumulated in the horizontal position; and 
         FIG. 24  is a diagrammatic elevation view showing bills accumulated in the inclined position. 
     
    
    
     BEST MODE FOR IMPLEMENTING THE INVENTION 
     Next, embodiments of a medium accumulating device according to the present invention will be described in detail with reference to appended figures. In the present application, like constituents are given the same reference numerals and repetitive description thereon will be avoided. 
     In this application, a plurality of constituents having substantially the same functional configuration may be distinguished from each other by adding different subscripts to the same reference numeral. For example, as described later,  FIG. 3  shows three bill storage cassettes  34  having substantially the same functional configuration, which it is necessary to distinguish them from one another, they are designated with reference numerals, e.g.  34 A,  34 B and  34 C. If they need not be distinguished from each other, they are designated with the bill storage cassette  34  without subscript. 
     With the embodiments of the invention that will be described below, media to be accumulated on an accumulation table are bills, which are merely an example and the present invention is not to be limited to the embodiments. For example, media to be accumulated on the accumulation table may be magnetic cards or IC (Integrated Circuit) cards such as cash cards or credit cards, bankbooks, securities, or tickets for transport or events such as railway tickets, boat tickets, boarding tickets or coupons. 
     Referring first to  FIGS. 1 and 2 , the configuration of an automatic transaction device in accordance with an embodiment of the present invention will be described.  FIG. 1  is a schematic perspective appearance view of the automatic transaction device in accordance with the embodiment of the present invention. As shown in the figure, the automatic transaction device  1  includes an operation/display  10 , a card/statement handler  11 , a bankbook handler  12 , a bill inlet/outlet port  13  and a coin inlet/outlet port  14 . 
     The automatic transaction device  1  is installed in various spots such as banks and stations, and in this embodiment, is a terminal device connected to a central processing system such as a server or a host computer of a financial facility over a telecommunications network  501 ,  FIG. 2 , to make transactions required from the customer. Specifically, the operation/display  10  of the automatic transaction device  1  includes functions of presenting a display screen of guiding an operation to the customer and of accepting entries by a customer&#39;s manual operation. As the function of accepting the operating input, the operation/display  10  may be implemented by, for example, a touch panel that senses touches on the screen to accept input. 
     The card/statement handler  11  is a functional section that receives or discharges a magnetic card or an IC card, such as a cash card, that is, a plastic card, not shown, for use in transaction, and discharges a paper strip, i.e. statement, not shown also, on which details of transaction are recorded. The bankbook handler  12  is a functional section that receives or discharges a bankbook, not shown, for use in transaction. The bill inlet/outlet port  13  is a functional section that receives or ejects bills. The coin inlet/outlet port  14  is a functional section that receives or ejects coins. The bill inlet/outlet port  13  and the coin inlet/outlet port  14  are provided with respective shutters, both not shown, which are driven by a driver or drivers to mechanically shield against the outside. 
       FIG. 2  is a schematic functional block diagram showing the configuration of the automatic transaction device  1  in accordance with the embodiment shown in  FIG. 1 . As shown in the figure, the automatic transaction device  1  includes, in addition to the operation/display  10 , card/statement handler  11 , bankbook handler  12 , bill inlet/outlet port  13  and coin inlet/outlet port  14 , a controller  15 , a hard disc device (HDD)  16 , a maintenance console  17 , a vein authenticator  18  and a communicator  19 . 
     The operation/display  10  includes a display section that displays a display screen guiding operations to the customer, and a customer operating section that detects the customer&#39;s manipulation. The function of the display section is implemented by, for example, a cathode ray tube (CRT) display device, a liquid crystal display (LCD) device or an organic light-emitting diode (OLED) device. The function of the customer operating section is implemented by, for example, a touch panel or a mechanical button, not shown. In the automatic transaction device  1  in the instant embodiment, the functions of the display section and the customer operating section are integrated with each other, but the functions of the display section and the customer operating section may be separated from each other. 
     The card/statement handler  11  is a functional section that reads data from a magnetic card or IC card, such as a cash card the customer presents, and prints transaction details on a paper strip to issues and discharge it as a transaction statement. The bankbook handler  12  is a functional section that prints the content of the transaction made by the automatic transaction device  1  on a bankbook inserted by the customer. 
     The bill inlet/outlet port  13  is a functional section that counts bills to be returned to the customer or bills to be withdrawn on a withdrawal transaction according to the denominations of bill, and transfers bills to the position where the customer can take the bills. The bill inlet/outlet port  13  also has a function to inspecting bills entered by the customer on a deposit transaction, and counting the bills according to the denominations of bill to store the bills in the automatic transaction device  1 . 
     The coin inlet/outlet port  14  is a functional section that inspects coins entered by the customer on a deposit transaction, and counts the coins according to the denominations of coin to store the coins in the automatic transaction device  1 . The coin inlet/outlet port  14  also has a function of counting coins to be withdrawn on a withdrawal transaction, and transfers the coins to the position where the customer can take the coins. 
     The controller  15  has an overall control function of generally controlling operations of the entire automatic transaction device  1 . The controller  15  includes, for example, functions of a communication control that controls communication between the communicator  19  and a host computer, not shown, and a display control that controls display screens to be displayed on the operation/display  10 . The controller  15  further includes a determiner  20 , which is a functional section that is responsive to sensor results of an accumulation table sensor  37  and a medium sensor  38 , described later,  FIG. 3  to determine whether or not a bill is put on an accumulation table  164 ,  FIG. 10 , in a reject cassette  35 . Details of the determiner  20  will be described later with reference to  FIG. 14 . 
     The hard disc drive (HDD)  16  is a storage device that stores control program sequences, files and the like, which are necessary for operating the automatic transaction device  1 . 
     The maintenance console  17  is an interface for the clerk, and has the functions of displaying information such as failures and troubles of the respective sections of this device, and of accepting a clerk&#39;s operation for addressing the failures or troubles of those sections. 
     The vein authenticator  18  is an authenticator for confirming personal identification. In the instant embodiment, the customer is identified by reading a vein pattern of a customer&#39;s palm and comparing the read vein pattern with a vein pattern recorded in advance on the IC chip, not shown, of a cash card inserted into the card/statement handler  11  by the customer. 
     The communicator  19  is an interface with a host computer for transmitting and receiving information necessary for transaction to and from the host computer over a telecommunications line  501 . The information necessary for transaction includes, for example, customer information such as an account number, a password and a balance in account of the customer, and information on transaction content, such as the deposited or withdrawn amount of money. 
     Subsequently, referring to  FIG. 3 , description will be made on the schematic configuration of the bill inlet/outlet port  13  of the automatic transaction device  1 .  FIG. 3  is a schematic functional block diagram showing an example of the configuration of the bill inlet/outlet port  13 . As can be seen from the figure, the bill inlet/outlet port  13  includes a customer serving section  31 , a discriminator  32 , a temporary storage  33 , bill storage cassettes  34 A,  34 B and  34 C, a reject cassette  35 , a left bill depository  36 , an accumulation table sensor  37 , and a bill sensor  38 . 
     The customer serving section  31  functions as an inlet section that separates bills put by the customer one by one on a deposit transaction and transfers the bills to, for example, the discriminator  32 . The customer serving section  31  collects bills to be returned to the customer or bills to be delivered to the customer on a withdrawal transaction. 
     The discriminator  32  determines the real/counterfeit, denomination and damage of bills transferred from the customer serving section  31 , as well as detects a transfer failure and counts the bills whose denomination has been established. In the context, the denomination of bill is directed to the denomination of bills predominantly circulating in one region, such as 1000-yen, 5000-yen and 10000-yen bills. 
     The temporary storage  33  is a functional section that temporarily holds a bill discriminated to be acceptable by the discriminator  32  on a deposit transaction until the deposit is established. 
     The bill storage cassettes  34 A,  34 B and  34 C are storages that store bills entered in the customer serving section  31  by the customer. Bills to be withdrawn to the customer are also stored in the bill storage cassettes  34 A,  34 B and  34 C to be taken out therefrom. 
     The reject cassette  35  is a storage section that stores bills which would the discriminator  32  has determined not be fed to the customer on a withdrawal or deposit transaction but to be collected. For example, the discriminator  32  may be configured to discriminate bills of denomination unfixed, specified denomination, damaged or dirtied as bills to be collected. The bills stored in the reject cassette  35  will be taken out and collected by the operator. Such a reject cassette  35  and the automatic transaction device  1  having such a reject cassette  35  are specific to automated teller machines, which are adapted to accumulate bills as media, and are a mere example of medium accumulating device according to the present invention. 
     The left bill depository  36  is a storage that stores bills left by the customer on a withdrawal or deposit transaction. 
     The accumulation table sensor  37  is an optical sensor that senses the accumulation table  164 ,  FIG. 10 , in the reject cassette  35 , on which bills will be accumulated. The bill sensor  38  is an optical sensor that detects whether or not a bill is accumulated on the accumulation table  164  in the reject cassette  35 . 
     A specific configuration that detects whether or not a bill is put on the accumulation table  164  in the reject cassette  35  will be described in comparison with comparative examples. First, the reject cassette that accumulates a medium in its horizontal position will be described with reference to  FIGS. 4A to 5B . 
       FIG. 4A  is a schematic vertical sectional view showing the configuration of a reject cassette  100  in accordance with Comparative Example 1. The reject cassette  100  includes a driving roller  101 , an idle roller  102 , an accumulation table  104 , and a stage spring  103 . In order to determine whether or not bills  301  are accumulated in the reject cassette  100 ,  FIG. 4B , there are provided outside the reject cassette  100  a residue detector  201  in the form of an assembly of light-emitter  201   a  and optical sensor  201   b , and a residue detector  202  in the form of an assembly of light-emitter  202   a  and optical sensor  202   b.    
     Since the reject cassette  100  is a cassette that is dedicated for accumulation as described above and would not feed out accumulated bills, no electrical component is provided in a medium accumulation space  105  but as shown in  FIG. 4A , the residue detectors  201  and  202  are provided outside the reject cassette  100 . Since the reject cassette  100  may store a bent bill, it is necessary to provide such a plurality of residue detectors  201  and  202  so as to monitor plural spots on the accumulation table  104 . 
     In the reject cassette  100  in Comparative Example 1, the bills  301  are drawn from the transfer path, not shown, by the driving roller  101  and the idle roller  102  into the cassette  100  to be accumulated on the accumulation table  104 . The accumulation table  104  is supported by the stage spring  103 , and guided by a sliding groove and a shaft, not shown, to be lowered in the direction of an arrow  107  by the self-weight of the accumulated bills  301 ,  FIG. 4B . 
     The residue detectors  201  and  202  provided in the reject cassette  100  form respective optical paths  109  and  111  in substantially the same direction as the moving direction of the accumulation table  104 , and are arranged so that the optical paths  109  and  111  pass respective, optically transparent holes  113  and  115 , which are provided in the accumulation table  104 . Accordingly, when the accumulation table  104  is located at any position in a vertical direction  107 , that is, at any height, the optical path  109  or  111  is blocked while the bills  301  are accumulated on the accumulation table  104 , so that it can be determined that the bills  301  exist in the cassette  100 . 
       FIG. 5A  is a schematic vertical sectional view showing the configuration of a reject cassette  110  in accordance with Comparative Example 2. In the case where the distance between a residue detector  211  including a light-emitter  211   a  and an optical sensor  211   b  and the accumulation table  104  is small, and the sensitivity of the residue detector  211  is sufficient, an optical prism  112  that refracts and guides the optical path  109  as shown in the figure may be provided in the accumulation table  104  such that the optical path  109  is blocked by the bills  301  as shown in  FIG. 5B . This can reduce the number and mounting space of the sensors, thereby miniaturizing the device. 
     In the reject cassettes  100  and  110  in the above-mentioned comparative examples, the width of the reject cassette, which corresponds to the side of the bill  301  in the transfer direction, when viewed from the accumulating direction  107  of the bills  301 , that is, from above in the figures, needs to be equivalent to the sum of the width of the transfer path, larger one of the widths of the driving roller and the idle roller, and the width of the bill storing section (accumulation table), which would restrict the miniaturization. 
     By contrast, in Comparative Example 3, an accumulation table  124  has its bill accumulating surface inclined as shown in  FIG. 6A , and the bills  301  transferred on a transfer path, not shown, provided above a reject cassette  120  are accumulated vertically in the inclined position thereof along the inclined surface as shown in  FIG. 6B . That allows that width of the reject cassette  120  which corresponds to the side of the bill in the transfer direction to be decreased with less restriction, thereby implementing the thinner cassette. 
     In this Comparative Example, a residue detector  221  including a light-emitter  221   a  and an optical sensor  221   b  as well as a residue detector  222  including a light-emitter  222   a  and an optical sensor  222   b  are provided so as to form the respective optical paths  109  and  111  in the same direction as the moving, that is, lifting and lowering direction  107  of the accumulation table  124 . Thus, as in Comparative Example 1, when the accumulation table  104  is located at any position in the vertical direction  107 , the optical path  109  or  111  is blocked while the bills  301  are accumulated on the accumulation table  124 , so that it can be determined that the bills  301  exist in the cassette  120 . 
     In a reject cassette  130  in Comparative Example 4, as shown in  FIG. 7A , where the distance between residue detector  231  including a light-emitter  231   a  and an optical sensor  231   b  and an accumulation table  134  is small, and the sensitivity of the residue detector  231  is sufficient, an optical prism  131  that refracts and guides the optical path  109  is provided in the accumulation table  134  such that the optical path  109  is blocked by the bills  301  as shown in  FIG. 7B . This can reduce the number and mounting space of the sensors, thereby miniaturizing the device. 
     The thin reject cassettes  130  and  140  in Comparative Examples 3 and 4 are configured so as to accumulate the bills  301  in the inclined position thereof. Such accumulation in the inclined position can decrease the required width of the accumulation space  105 , implementing the thinner reject cassette. Now, the height of the accumulation space  105 , which is required for the accumulation in the inclined position, will be described as compared to the height required for the accumulation in the horizontal position. 
     First, the height of the accumulation space, which is required for the accumulation in the horizontal position, will be described with reference to  FIG. 23 . As can be seen from the figure, the height of the accumulation space, which is required to accumulate the bills  301  in the horizontal position, is of course equal to the height H where the bills  301  are accumulated. 
     The height of the accumulation space  105 , which is required when the same number of bills  301  as the example shown in  FIG. 23  are accumulated in the inclined position, will be described with reference to  FIG. 24 . As can be seen from the figure, the height of the accumulation space, which is required when the bills  301  are accumulated at an inclination angle θ, is found according to the following expression (1).
 
[Expression 1]
 
 B  sin θ+ H /cos θ,  (1)
 
where 0≦θ≦90°, 0&lt;sin θ&lt;1 and 0&lt;cos θ&lt;0.
 
     Thus, with the thin reject cassettes  120  and  130  that accumulate the bills  301  in the inclined position, as the angle θ of the bills  301  is larger, the width of the accumulation space  105  can be smaller, but the height of the accumulation space  105  needs to be larger. Accordingly, with the thin reject cassette  120  that is shorter in the width direction and longer in the height direction, the distance between the light-emitter and the optical sensor on each of the optical paths  109  and  111  formed by the residue detectors  221  and  222 , respectively, is longer than that in the example shown in  FIG. 4A  by the lengths represented by broken lines  109   a  and  111   a  in  FIG. 6A . This requires an expensive high-sensitive sensor, thus problematically leading to an increase in costs. Further, since a driving roller  121  and an idle roller  122  exist between the light-emitter  221   a  and the optical sensor  221   b , the positional arrangement of the light-emitter  221   a  and the optical sensor  221   b  that form the optical path  109  is disadvantageously restricted. 
     Thus, in Comparative Example 5 shown in  FIG. 8A , the above-mentioned problem is solved by arranging a residue detector  241  so as to form the optical path  109  from a light-emitter  241   a  to an optical sensor  241   b  in a direction that is different from the moving, that is, lifting and lowering direction  107  of an accumulation table  144 ,  FIG. 8B . In the reject cassette  140 , when the optical path  109  formed by the residue detector  241  is not blocked by the bills  301 , it is determined that no bill exists. However, depending on the weight and thickness of the bills  301  accumulated on the accumulation table  144 , the accumulation table  144  may lower across a length exceeding a designed value, so that the bills  301 , although accumulated as shown in  FIG. 8B , fail to interrupt the optical path  109  to be determined as no bill existing. 
     Now, a reject cassette  150  in accordance with Comparative Example 6 shown in  FIG. 9  has a plurality of optical paths  109 ,  111 ,  118  and  119  formed in a distance over which the accumulation table  144  moves to thereby detect whether or not the bills  301  are accumulated whatever position the accumulation table  144  may occupy. 
     Alternatively, an actuator, not shown, that raises and lowers the accumulation table  144  may be added, and the upper surface of the uppermost accumulated bills  301  may be controlled in height so as to fall within the optical path  109  formed by the residue detector. 
     However, any of the above-mentioned configurations in Comparative Example 6 disadvantageously cause an increase in costs and space of the device. 
     Thus, taking account of those circumstances, the Inventor made the present invention. In accordance with embodiments of the present invention, it is detected an accumulation table on which bills are accumulated is lowered, thereby making it possible to determine whether or not media are accumulated on the accumulation table. Embodiments of the present invention will be described in detail. 
       FIG. 10  is a schematic vertical sectional view showing the configuration of a reject cassette  35 - 1  in accordance with the first embodiment of the present invention.  FIG. 12  is a schematic perspective view of the reject cassette  35 - 1  in accordance with the embodiment shown in  FIG. 10 . As can be seen from  FIGS. 10 and 12 , the reject cassette  35 - 1  in accordance with the instant embodiment includes a driving roller  161 , an idle roller  162 , a stage spring  163 , an accumulation table  164  and a stage detector  165 . 
     Outside the reject cassette  35 - 1 , there is provided a bill sensor  38  including a set of light-emitter  38   a  and optical sensor  38   b , which forms an optical path  109  in a direction intersecting the moving direction  107  of the accumulation table  164  and detects whether or not bills  301  are accumulated. Outside of the reject cassette  35 - 1 , there is also provided an accumulation table sensor  37  including a set of light-emitter  37   a  and optical sensor  37   b , which also detects the lowering of the accumulation table  164 . Constituents of the reject cassette  35 - 1  will be described below. 
     The driving roller  161  and the idle roller  162  are feeder members that draw the bills  301  from the transfer path, not shown. The stage spring  163  is an elastic member that supports the accumulation table  164 . Although  FIG. 10  shows one stage spring  163  as an example of the elastic member, the present invention is not limited to this example. For example, a plurality of springs may be provided as elastic members supporting the accumulation table  164 . In addition, although  FIG. 10  exemplarily shows the spring as an elastic member, an elastic member elastically deformable depending on the load of bills may be used. 
     The accumulation table  164  has its inclined surface  164   a  inclined with respect to the lifting and lowering direction  107  of the accumulation table  164 . The inclined surface  164   a  may be sufficient to at least partially support the accumulated bills  301 ,  FIG. 11A , that is, may be partially opened or reticulated. Preferably, the inclined surface  164   a  forms a flat plane. The bills  301 ,  FIG. 13 , drawn by the driving roller  161  and the idle roller  162  are accumulated on the inclined surface  164   a . As the bills  301  are accumulated on the accumulation table  164 , the stage spring  163  is compressed by the weight of the accumulated bills  301 . More specifically, as the bills  301  are accumulated on the accumulation table  164 , the accumulation table  164  supported by the stage spring  163  lowers in the direction of the arrow  107  with the compression of the stage spring  163 . 
     As shown in  FIG. 12 , the stage detector  165  is fixed on the accumulation table  164  at such a position, outside the region where the bills  301  will be accumulated, as not to interfere with the optical path  109  formed by the bill sensor  38 . Thus, the stage detector  165  moves in the lifting and lowering direction  107  together with the accumulation table  164 . The stage detector  165  is provided at a position where an optical path  117  formed by the accumulation table sensor  37  is blocked by the accumulation table  164 , when lifted above a predetermined height, i.e. predetermined position in the lifting and lowering direction  107 , of the accumulation table  164 . The predetermined position may be, for example, a home position of the accumulation table  164 , or a height taken when the bills  301  are hardly accumulated. 
     As described above, the reject cassette  35 - 1  in accordance with the present embodiment is arranged, as shown in  FIG. 12 , such that, when the accumulation table  164  lifts above the predetermined position, the stage detector  165  provided on the accumulation table  164  blocks the optical path  117  formed by the accumulation table sensor  37 . By contrast, when the accumulation table  164  lowers below the predetermined position, the stage detector  165  lowers together with the accumulation table  164 , resulting in that the optical path  117  formed by the accumulation table sensor  37  is not blocked by the stage detector  165 . As described above, depending on whether or not the optical path  117  formed by the accumulation table sensor  37  is blocked by the stage detector  165 , it can be determined whether or not the accumulation table  164  lowers below the predetermined position. 
     The bill sensor  38  includes, as described above, the light-emitter  38   a  and the optical sensor  38   b . The light-emitter  38   a  and the optical sensor  38   b  are, as shown in  FIG. 12 , opposed to each other across the accumulation table  164 . As can be seen from the figure, when no bill  301  is accumulated on the accumulation table  164 , which is located at its uppermost position in the lifting and lowering distance, that is, home position, the optical path  109  formed from the light-emitter  38   a  toward the optical sensor  38   b  passes through an optical slit  113  formed in the accumulation table  164 . By contrast, as shown in  FIG. 13 , when the bills  301  are accumulated on the accumulation table  164 , the optical path  109  formed from the light-emitter  38   a  toward the optical sensor  38   b  is blocked by the bills  301  as long as the accumulation table  164  is located above the predetermined position. As described above, the reject cassette  35 - 1  is configured such that when the stage detector  165  blocks the optical path  117  formed by the accumulation table sensor  37 , the bill sensor  38  can detect that the bills  301  are accumulated on the accumulation table  164 . Although the accumulation table  164  has at least its part, that is, the optical slit  113  in the present embodiment, optically transparent, the entire accumulation table  164  may be transparent. 
     In the embodiment shown in  FIG. 2 , the determiner  20  uses the detection results of the accumulation table sensor  37  and the medium sensor  38  to determine whether or not the bills  301  are accumulated on the accumulation table  164  of the reject cassette  35 - 1 . Referring to  FIG. 14 , the determination function of the determiner  20  will be specifically described below. 
       FIG. 14  shows the detection results of the accumulation table sensor  37  and the bill sensor  38  and determination logics of the determiner  20 . In the instant embodiment, since the sensors  37  and  38  are optical sensors, when light beams  109  and  111  emitted from the light-emitters  37   a  and  38   a , respectively, are received by the optical sensors  37   b  and  38   b , the detection results show “bright”, and when the optical paths  109  and  111  are blocked by the bills  301  and the stage detector  165 , respectively, the detection results show “dark”. 
     As can be seen from  FIG. 14 , the determiner  20  determines that the bills  301  are accumulated on the accumulation table  164  when the detection result of the accumulation table sensor  37  shows “bright” or the detection result of the bill sensor  38  shows “dark”. In other words, the determiner  20  determines that the bills  301  are accumulated on the accumulation table  164  when the accumulation table sensor  37  senses that the accumulation table  164  lowers below the predetermined position, or the bill sensor  38  senses that the bills  301  are accumulated. 
     By contrast, when the detection results of the accumulation table sensor  37  and bill sensor  38  shows “dark” and “bright”, respectively, the determiner  20  determines that no bill  301  is accumulated on the accumulation table  164 . In other words, when the accumulation table sensor  37  senses that the accumulation table  164  is located above the predetermined position, and the bill sensor  38  does not sense that the bills  301  are accumulated, the determiner  20  determines that no bill  301  is accumulated on the accumulation table  164 . 
     Subsequently, referring to  FIGS. 11A ,  11 B and  11 C, description will be made on a state transition during the accumulation of the bills  301  in the reject cassette  35 - 1 , that is, a process of lowering the accumulation table  164  will be described. Those figures are schematic, vertical sectional view specifically showing the state transition during the accumulation of the bills  301  in the reject cassette  35 - 1 . 
     When no bill  301  is accumulated on the accumulation table  164  of the reject cassette  35 - 1 , as shown in  FIG. 10 , the accumulation table  164  is raised to its home position by the stage spring  163 . After that, when the bills  301  are accumulated on the accumulation table  164 , as shown in  FIG. 11A , the optical path  109  formed by the bill sensor  38  is blocked by the bills  301 . If the accumulation table  164  lowers more or less due to the weight of the accumulated bills  301 , as long as the accumulation table  164  resides above the predetermined position, the optical path  109  formed by the accumulation table sensor  37  is then blocked by the stage detector  165 . At this time, since the detection results of both accumulation table sensor  37  and bill sensor  38  show “dark”, the determiner  20  determines that the bills  301  are accumulated on the accumulation table  164  according to the logical relationship shown in FIG.  14 . 
     Then, as shown in  FIG. 11B , when the bills  301  are further accumulated on the accumulation table  164 , the accumulation table  164  lowers due to the weight of the bills  301 , and the optical path  117  formed by the accumulation table sensor  37  becomes not blocked by the stage detector  165  provided in the accumulation table  164 , whereas the optical path  109  formed by the bill sensor  38  is still blocked by the bills  301 . Thus, since the detection results of the accumulation table sensor  37  and bill sensor  38  show “bright” and “dark”, respectively, the determiner  20  determines that the bills  301  are accumulated on the accumulation table  164  according to the logical relationship shown in  FIG. 14 . 
     However, depending on the weight or thickness of the bills  301 , for example, when the bills  301  are wet, as shown in  FIG. 11C , the accumulation table  164  may be lowered further from the normal position, and thus the optical path  109  formed by the bill sensor  38  may become not blocked by the bills  301 . However, in this case, since the detection results of both of the accumulation table sensor  37  and the bill sensor  38  show “bright”, the determiner  20  determines that the bills  301  are accumulated on the accumulation table  164  according to the logical relationship shown in  FIG. 14 . 
     However, when the operator removes all of the bills  301  from the reject cassette  35 - 1 , the bill weight becomes zero, and the accumulation table  164  is raised to a stopper, not shown, by the repulsive force of the stage spring  163  and returns to its home position. At the home position, as shown in  FIG. 10 , the optical path  117  formed by the accumulation table sensor  37  is blocked by the stage detector  165 . However, the optical path  109  formed by the bill sensor  38  is not blocked by the bills  301 . Thus, since the detection result of the accumulation table sensor  37  and bill sensor  38  show “dark” and “bright”, respectively, the determiner  20  determines that no bill  301  is accumulated on the accumulation table  164  according to the logical relationship shown in  FIG. 14 . 
     In summary, in the instant embodiment, it is detected whether or not the accumulation table  164  lowers below the predetermined position depending on whether or not the optical path  117  formed by the accumulation table sensor  37  is blocked by the stage detector  165 . In the embodiment, when the accumulation table  164  lowers below the predetermined position, the determiner  20  determines that the bills exist in any case. Depending on the weight of the bills  301 , however, when the accumulation table  164  does not lower below the predetermined position, the bills  301  may be accumulated on the accumulation table  164  as shown in  FIG. 11A . Thus, the bill sensor  38  is configured so as to determine whether or not the bills  301  are accumulated on the accumulation table  164  at least when the accumulation table  164  is located above the predetermined position. It can thus be determined more correctly whether or not the bills  301  are accumulated. 
     In the instant embodiment, the optical paths  109  and  111  of the sensors  37 ,  38  may be formed in a direction that is different from the lifting and lowering direction  107  of the accumulation table  164 , in which case the determiner  20  can correctly determine whether or not the bills  301  are accumulated, irrespective of the position of the accumulation table  164  or the bill accumulation state. 
     In accordance with the present embodiment, whether or not the accumulated bills  301  are accumulated on the accumulation table  164  can be correctly determined with a small number of sensors without providing, as in Comparative Example 6 shown in  FIG. 9 , plural sensors  251  in the lifting and lowering direction  107  of the accumulation table  144 , thus reducing costs of the entire device. 
     In the present embodiment, since the optical path  109  of the sensor need not be parallel to the lifting and lowering, that is, moving direction  107  of the accumulation table  164 , the sensors may be applied to the thin cassette  120 ,  FIG. 6A , as in Comparative Example 3 in which the bills are accumulated in the inclined position, the distance between the sensors will not be extended. Therefore, an inexpensive sensor can be used instead of an expensive long-distance sensor. 
     In the instant embodiment, since the optical path  109  of the sensor can be formed in a direction that is different from the lifting and lowering direction  107  of the accumulation table  164 , the sensor optical path is not affected by the driving roller  161  and the idle roller  162 , and therefore, the sensor can be freely arranged in position. 
     Well,  FIG. 15  is a schematic vertical sectional view showing the configuration of a reject cassette  35 - 2  in accordance with the second embodiment of the present invention. As shown in the figure, the reject cassette  35 - 2  in accordance with the instant embodiment has first and second prisms  171  and  173  in addition to the driving roller  161 , the idle roller  162 , the stage spring  163 , the accumulation table  164  and the stage detector  165 . 
     On one side of the reject cassette  35 - 2 , that is, on the left side in  FIG. 15 , a bill sensor  38  including a set of light-emitter  38   a  and optical sensor  38   b  is provided to form the optical path  109  in the direction intersecting with the moving direction  107  of the accumulation table  164  to detect whether or not bills  301  are accumulated. Outside the reject cassette  35 - 1 , the accumulation table sensor  37  is provided which includes a set of light-emitter  37   a  and an optical sensor  37   b  to sense the accumulation table  164  being lowered. The constituents will be described below. 
     Since the driving roller  161 , the idle roller  162 , the stage spring  163 , the accumulation table  164  and the stage detector  165  may be the same as the first embodiment, the description thereof will not be repeated. 
     The first prism  171  is an optical element which has its side shaped as illustrated and refracts the light beam  109  emitted from the light-emitter  38   a  of the bill sensor  38  to guide the latter to the optical sensor  38   b . The second prism  173  is also an optical element that has its side shaped as illustrated and refracts the light beam  111  from the light-emitter  37   a  of the accumulation table sensor  37  to guides the latter to the optical sensor  37   b . The prisms  171  and  173  may be fixedly provided at a position that does not move with movement of the accumulation table  164 , for example, on the housing of the cassette  35 - 2 . 
     As described above, in the instant embodiment, the provision of the prisms  171  and  173  that guide the light beams  109  and  111 , respectively, renders both of the sensors  37  and  38  arranged on one side of the reject cassette  35 - 2 . That makes the mounting space for the sensors  37  and  38  decreased approximately half as much as the first embodiment, further reducing the size of the entire device. The bill sensor  38 , thus including the first prism  171 , alone causes the two optical paths  109  to be formed so as to intersect with the moving direction  107  of the accumulation table  164 . This can further reduce the number of sensors, thereby reducing costs of the entire device. 
     The determiner  20  shown in  FIG. 2  uses detection results of the accumulation table sensor  37  and the medium sensor  38  to determine whether or not the bills  301  are accumulated on the accumulation table  164  of the reject cassette  35 - 2 . The logical relationship shown in  FIG. 14  is applied to the determination logic of the determiner  20  as it is. 
     Subsequently, a state transition during the accumulation of the bills  301  in the reject cassette  35 - 2 , that is, lowering of the accumulation table  164  will be described with reference to  FIGS. 16A ,  16 B and  16 C. Those figures are schematic vertical sectional views specifically showing the state transition during the accumulation of the bills  301  in the reject cassette  35 - 2 . When no bill is accumulated, the accumulation table  164  of the reject cassette  35 - 2  is raised to its home position by the stage spring  163  as shown in  FIG. 15 . 
     Then, as shown in  FIG. 16A , when the bills  301  are accumulated on the accumulation table  164 , the optical path  109  formed by the bill sensor  38  is blocked by the bills  301 . When the accumulation table  164  lowers more or less due to the weight of the accumulated bills  301 , and remains above the predetermined position, the optical path  117  formed by the accumulation table sensor  37  is blocked by the stage detector  165 . At this time, since the detection results of both accumulation table sensor  37  and bill sensor  38  show “dark”, the determiner  20  determines that the bills  301  are accumulated on the accumulation table  164  according to the logical relationship shown in  FIG. 14 . 
     After that, as shown in  FIG. 16B , when the bills  301  are further accumulated on the accumulation table  164 , the accumulation table  164  lowers due to the weight of the bills  301 , and the optical path  117  formed by the accumulation table sensor  37  becomes unblocked by the stage detector  165  provided on the accumulation table  164 . However, as shown in the figure, the optical path  109  formed by the bill sensor  38  is still blocked by the bills  301 . Thus, the detection results of the accumulation table sensor  37  and the bill sensor  38  show “bright” and “dark”, respectively, so that the determiner  20  determines that the bills are accumulated on the accumulation table  164  according to the logical relationship shown in  FIG. 14 . 
     As in the earlier-described embodiment, depending on the weight or thickness of the bills  301 , for example, when the bills  301  are wet, as shown in  FIG. 16C , the accumulation table  164  may be lowered further from the normal position, and thus the optical path  109  formed by the bill sensor  38  may become not blocked by the bills  301 . However, in this case, since the detection results of both accumulation table sensor  37  and bill sensor  38  show “bright”, the determiner  20  determines that the bills are accumulated on the accumulation table  164  according to the logical relationship shown in  FIG. 14 . 
     Now, when the operator removes all of the bills  301  from the reject cassette  35 - 2 , the bill weight becomes zero, and the accumulation table  164  is raised to the stopper, not shown, by the repulsive force of the stage spring  163  and returns to its home position. At the home position, as shown in  FIG. 15 , the optical path  117  formed by the accumulation table sensor  37  is blocked by the stage detector  165  whereas the optical path  109  formed by the bill sensor  38  is not blocked by the bills  301 . Thus, the detection result of the accumulation table sensor  37  shows “dark”, or the detection result of the bill sensor  38  shows “bright”, so that the determiner  20  determines that no bill is accumulated on the accumulation table  164  according to the logical relationship shown in  FIG. 14 . 
     In summary, in the present embodiment, the provision of the prisms  171  and  173  that guide the optical paths  109  and  117 , respectively, allows the sensors  38  and  37  to be arranged in one side of the reject cassette  35 - 2 . That makes the sensor mounting space to be decreased about half as much as the earlier-describe embodiment, enabling further reduction of the device in size. 
     Although the embodiment shown in  FIGS. 15 and 16  has the prisms  171  and  173  that refract or reflect the light beams  105  and  117 , respectively, this is merely an example, and the present invention is not limited to such an example. In place of the prisms, other light-guiding members that reflect and guide light, such as reflective plates and optical fibers, may be applied. 
     In the instant embodiment, the bill sensor  38  may be provide in plural so as to form a plurality of optical paths corresponding to the size of the bills  301  to be sensed. For example, as shown in  FIG. 17 , the reject cassette  35 - 2  is provided with two sets of bill sensors  38  to form four optical paths  109 . 
     In the example shown in  FIG. 17 , the optical paths  109  passing through the accumulation table  164  are provided at heights different from each other. Thus, as shown in  FIG. 18 , even when a broken or bent bill  301   a  is placed on the accumulation table  164 , the bill  301   a  can be sensed once at least one of the optical paths  109  formed by the bill sensor  38  is interrupted. 
       FIG. 19  is a schematic vertical sectional view showing the configuration of a reject cassette  35 - 3  in accordance with a third embodiment of the present invention.  FIG. 21  is a schematic perspective view of the reject cassette  35 - 3  in accordance with this embodiment. As can be seen from  FIGS. 19 and 21 , the reject cassette  35 - 3  has a prism  181  in addition to the driving roller  161 , the idle roller  162 , the stage spring  163  and the accumulation table  164 . The driving roller  161 , idle roller  162 , stage spring  163  and accumulation table  164  may be the same as in the above-mentioned embodiments. 
     The prism  181  is configured so as to refract the light beam  117  emitted from the light-emitter  37   a  of the accumulation table sensor  37  and guide the latter to the optical sensor  37   b , and is fixedly provided at a point that does not move with the movement of the accumulation table  164 , for example, the housing of the cassette  35 - 3 . 
     In the instant embodiment, between the reject cassette  35 - 3  and the accumulation table sensor  37  a shutter  182  is provided. The shutter  182  is generally made of an optically opaque, light-blocking material that blocks the optical path  117 , but has its part cut into an optical through hole  182   a  that allows the optical path  117  formed by the accumulation table sensor  37  to pass therethrough. 
     The shutter  182  is arranged so as to engage with the accumulation table  164  to lift and lower together with the accumulation table  164 . The shutter  182  may be configured to lift and lower along a sliding groove, not shown, or rotate about its rotational axis. In any case, as shown in  FIG. 21 , when the accumulation table  164  is located above the predetermined position, the shutter  182  is raised by the accumulation table  164 . In this state, the optical path  117  formed by the accumulation table sensor  37  passes through the hole  182   a  provided in the shutter  182  and a slit  113  provided in the accumulation table  164 . When the bills  301  are accumulated on the accumulation table  164 , the optical path  117  passing through the hole  182   a  provided in the shutter  182  is blocked by the bills  301 . As described above, the accumulation table sensor  37  in the present embodiment also functions as the bill sensor  38 . 
     When the accumulation table  164  lowers due to the self-weight of the accumulated bills  301 , the shutter  182  also lowers together with the accumulation table  164  to a position where the shutter blocks the optical path  117 , and will cease there. Specifically, as shown in  FIG. 21 , the shutter  182  is provided with a protrusion  183 , and when the shutter  182  lowers together with the accumulation table  164 , the protrusion  183  engages with a stopper  401 . This prevents further lowering of the shutter  182 . 
     The determiner  20  shown in  FIG. 2  uses the detection result of the accumulation table sensor  37  having the above-mentioned configuration to determine whether or not the bills  301  are accumulated on the accumulation table  164  of the reject cassette  35 - 3 . Since the sensor  37  in the instant embodiment is the optical sensor, when the light beam  117  emitted from the light-emitter  37   a  is received by the optical sensor  37   b , the detection result shows “bright”, whereas when the optical path  117  is blocked by the bills  301  or the shutter  182 , the detection result shows “dark”. 
     Thus, when the detection result of the accumulation table sensor  37  shows “bright”, the determiner  20  determines that no bill  301  is accumulated on the accumulation table  164 . That is the case where the accumulation table sensor  37  detects that the accumulation table  164  is located above the predetermined position, or fails to detect the accumulation of the bills  301 . In either case, the determiner  20  will determine that no bill is accumulated on the accumulation table  164 . 
     By contrast, when the detection result of the accumulation table sensor  37  shows “dark”, the determiner  20  determines that the bills  301  are accumulated on the accumulation table  164 . That is the case where the accumulation table sensor  37  detects that the accumulation table  164  lowers below the predetermined position, or senses the bills  301  accumulated. In either case, the determiner  20  will determine that the bills are accumulated on the accumulation table  164 . 
     Subsequently, a state transition while the bills  301  are accumulated in the reject cassette  35 - 3  and the cassette  35 - 3  lowers will be described with reference to  FIGS. 20A ,  20 B and  20 C. Those figures are schematic, vertical sectional views specifically showing the state transition during accumulation of the bills  301  in the reject cassette  35 - 3 . 
     When no bills  301  are accumulated on the accumulation table  164  of the reject cassette  35 - 3 , as shown in  FIG. 19 , the accumulation table  164  is raised to its home position by the stage spring  163 . After that, when the bills  301  are accumulated on the accumulation table  164 , as shown in  FIG. 20A , the optical path  117  formed by the accumulation table sensor  37  is blocked by the bills  301 . At this time, since the accumulation table sensor  37  shows “dark”, the determiner  20  determines that bills  301  are accumulated on the accumulation table  164 . 
     Then, as shown in  FIG. 20B , when the bills  301  are further accumulated on the accumulation table  164 , the accumulation table  164  lowers due to the weight of the bills  301 , and the shutter  182  also lowers together with the accumulation table  164 . That causes the optical path  117  formed by the accumulation table sensor  37  to be blocked by the shutter  182 . At this time, since the detection result of the accumulation table sensor  37  shows “dark”, the determiner  20  determines that bills  301  are accumulated on the accumulation table  164 . 
     Now, as shown in  FIG. 20C , depending on the weight or thickness of the bills  301   a , for example, when the bills are wet, the accumulation table  164  may further be lowered from the normal position shown in  FIG. 20B . In this case, although the shutter  182  also lowers together with the accumulation table  164 , the protrusion  183  provided on the shutter  182  engages with the stopper  401  as described above, so that the shutter  182  stops lowering at a height where the shutter  182  blocks the optical path  117  formed by the accumulation table sensor  37 . Accordingly, as shown in  FIG. 20C , the optical path  117  formed by the accumulation table sensor  37  is blocked by the shutter  182 . At this time, since the accumulation table sensor  37  shows “dark”, the determiner  20  determines that bills  301   a  are accumulated on the accumulation table  164 . 
     Then, when the operator entirely removes the bills  301  from the reject cassette  35 - 3 , the bill weight becomes zero, and the accumulation table  164  is raised to its home position by the stage spring  163  again. At the home position, as shown in  FIG. 19 , the optical path  117  formed by the accumulation table sensor  37  is not blocked. At this time, since the detection result of the accumulation table sensor  37  shows “bright”, the determiner  20  determines that no bill  301  is accumulated on the accumulation table  164 . 
     In summary, in the instant embodiment, the shutter  182  working with the accumulation table  164  is arranged. That allows the single optical sensor  37  to be used to more correctly determine whether or not the bills  301  are accumulated. Thus, the number of the sensors is reduced, enabling the interconnections and the size of circuit boards to be reduced, thereby implementing a device entirely reduced in size and cost. 
     In the first and second embodiments described earlier, when the detection result of the accumulation table sensor  37  shows “dark”, the determiner  20  determines that the accumulation table  164  is located above the predetermined position. However, the present invention is not limited to those specific embodiments. For example, depending on the configuration of the reject cassette  35 , the determiner  20  may determine that the accumulation table  164  is located above the predetermined position when the detection result of the accumulation table sensor  37  shows “bright”. Thus, a fourth embodiment will be shown in  FIG. 22 , in which the prism  191  may be attached to the accumulation table  164  so that the determiner  20  determines that the accumulation table  164  is located above the predetermined position when the detection result of the accumulation table sensor  37  shows “bright”. 
     Referring to  FIG. 22 , a reject cassette  35 - 4  in accordance with the fourth embodiment has a prism  191  in addition to the driving roller  161 , the idle roller  162 , the stage spring  163  and the accumulation table  164 . The driving roller  161 , idle roller  162 , stage spring  163  and accumulation table  164  may be the same as in the above-mentioned embodiments. 
     The prism  191  refracts the light beam  117  emitted from the light-emitter  37   a  of the accumulation table sensor  37  to guide the latter to the optical sensor  37   b . The prism  191  is attached to the accumulation table  164  so as to move with the movement of the accumulation table  164  at a position where the prism  191  guides the light beam  117  emitted from the light-emitter  37   a  to the optical sensor  37   b  when the accumulation table  164  is located above the predetermined position. 
     Since the sensor  37  in accordance with the fourth embodiment is an optical sensor, when the light beam  117  emitted from the light-emitter  37   a  is received by the optical sensor  37   b , the detection result of the sensor  37  shows “bright”, whereas when the light beam  117  is not received, the detection result of the sensor  37  shows “dark”. Thus, in the reject cassette  35 - 4  in accordance with the fourth embodiment, when the accumulation table  164  is located above the predetermined position, the prism  191  guides the light beam  117  emitted from the light-emitter  37   a  to the optical sensor  37   b , so that the detection result of the accumulation table sensor  37  shows “bright”. The detection result of the accumulation table sensor  37  thus showing “bright” causes the determiner  20  to determine that the accumulation table  164  is located above the predetermined position. 
     While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention. 
     For example, in the above-described embodiments, the optical sensors are used as the accumulation table sensor  37  and the bill sensor  38 . However, the present invention is not limited to this example. In place of or in addition to the optical sensors, sensors relying upon other operating principles, such as contact sensors or magnetic sensors, may be used as the accumulation table sensor  37  and the bill sensor  38 . 
     Although one set of bill sensors  38  are provided in the embodiments, the present invention is not limited to this example. For example, a required number of bill sensors, for example, two or three sets of bill sensors, may be arranged according to the size and shape of target bills. 
     Although the sensors are arranged outside of the reject cassette in the embodiments, such sensors may be provided within the reject cassette. 
     In the embodiments, the accumulation table  164  has the inclined surface, on which bills are accumulated in the inclined position. However, the present invention is not limited to this example. For example, the accumulation surface may be formed horizontal, on which bills may be vertically accumulated in the horizontal position. Also in this case, the accumulation table being lowered can be sensed to determine whether or not bills are accumulated on the accumulation table. 
     The entire disclosure of Japanese patent application No. 2010-189233 filed on Aug. 26, 2010, including the specification, claims, accompanying drawings and abstract of the disclosure, is incorporated herein by reference in its entirety.