Patent Publication Number: US-8522949-B2

Title: Paper sheet processing apparatus

Description:
FIELD OF THE INVENTION 
     The present invention relates to a paper sheet processing apparatus which judges an authenticity of a bill, a gift certificate, a coupon ticket, and so on (hereafter, these are collectively referred to as a paper sheet). 
     BACKGROUND ART 
     In general, a bill processing apparatus, which handles a bill as one of the embodiments of the paper sheet, is incorporated into a service device such as a game medium rental machine installed in a game hall, a vending machine or a ticket-vending machine installed in a public space, or the like which judges the authenticity of the bill inserted from a bill insertion slot by a user and provides various types of products and services in accordance with a value of the bill having been judged as authentic. 
     Generally, in a bill authenticity judgment process, for example as disclosed in Patent Reference 1, a bill moving along the bill travelling route is irradiated with light, and the transmitted light and reflected light from the bill are detected by a light receiving sensor and compared with reference data stored in dictionary data. More specifically, the transmitted light data and reflected light data from the conveyed bill are acquired, converted for example to brightness information, and compared with normal data.
     [Patent Reference 1] Japanese unexamined patent application publication No. H6-60242   

     DISCLOSURE OF THE INVENTION 
     Problem to be Solved by the Invention 
     The above transmitted light data and reflected light data may have a difference in brightness depending on the bill&#39;s condition. This may occur, for example, when the fibrous bill surface is wet, in other words when the fibrous, rough surface the bills generally have is optically smoothed. In such a case, diffuse reflection is presumably reduced on the smoothed part. In other words, when a bill is wet and its surface is smoothed, diffuse reflection on the bill surface is reduced and more light is transmitted through the bill; the transmitted light data present increased brightness (light intensity). On the other hand, the reflected light data present decreased brightness (light intensity) because diffuse reflection on the bill surface is reduced and more light is transmitted through the bill. 
     Consequently, when a wet bill is subject to a bill authenticity judgment process, the bill may not match the dictionary data because of a difference in brightness resulting from a changed amount of light obtained by the light receiving sensor even if the bill is a legitimate bill. In such a case, the bill may be identified to be a forged bill. 
     The present invention provides a paper sheet processing apparatus capable of preventing reduction in the accuracy of authenticity judgment even if paper sheets have some state change, such as being wet. 
     Means to Solve the Problem 
     In order to achieve the above purpose, the paper sheet processing apparatus comprises: a light emitting part which irradiates a paper sheet with light; a light receiving part which receives transmitted light through the paper sheet and reflected light from the paper sheet, the paper sheet being irradiated by the light emitting part; a converter which converts the transmitted light and reflected light received by the light receiving part into data including color information having brightness per pixel of a predetermined size as a unit; a storage part which stores a transmitted light image constituted of a plurality of pixels converted by the converter from the transmitted light received by the light receiving part and a reflected light image constituted of a plurality of pixels converted by the converter from the reflected light received by the light receiving part; an authenticity judgment processing part which judges an authenticity of the paper sheet based on each image stored by the storage part; and a determining part which excludes a predetermined area from an object for an authenticity judgment based on a comparison result between brightness of pixels in the predetermined area of the transmitted image and brightness of pixels of the reflected image corresponding to the predetermined area of the transmitted image. 
     Further features of the present invention, its nature, and various advantages will be more apparent from the accompanying drawings and the following description of the preferred embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing an entire structure to illustrate a configuration of a bill processing apparatus of this embodiment. 
         FIG. 2  is a perspective view showing the bill processing apparatus in a state that an open/close member is opened for a main body frame of an apparatus main body. 
         FIG. 3  is a right side view schematically showing a traveling route of a bill to be inserted from an insertion slot. 
         FIG. 4  is a right side view showing a schematic configuration of a power transmission mechanism for driving the presser plate arranged in a bill housing part. 
         FIG. 5  is a left side view showing a schematic configuration of a driving source and a driving force transmission mechanism to drive a bill conveyance mechanism. 
         FIG. 6  is a block diagram showing a configuration of control means which controls driving of driving members such as a bill conveyance mechanism, bill reading means, and the like. 
         FIG. 7  shows a flowchart (part one) illustrating processing operations for processing the bill in the bill processing apparatus of this embodiment. 
         FIG. 8  shows a flowchart (part two) illustrating processing operations for processing the bill in the bill processing apparatus of this embodiment. 
         FIG. 9  shows a flowchart (part three) illustrating processing operations for processing the bill in the bill processing apparatus of this embodiment. 
         FIG. 10  shows a flowchart illustrating processing operations of a traveling route opening process. 
         FIG. 11  shows a flowchart illustrating processing operations of a skew correction operating process. 
         FIG. 12  shows a flowchart illustrating processing operations of a traveling route closing process. 
         FIG. 13  shows a flowchart illustrating processing operations of a bill authenticity judgment process. 
         FIG. 14  is a schematic diagram of a reflected light image of a bill, which is divided into small areas. 
         FIG. 15  is a schematic diagram of a transmitted light image of a bill. 
         FIG. 16  is a schematic diagram of a reflected light image of a bill. 
         FIG. 17  illustrates examples of brightness data of pixels in an area including a predetermined area of a bill. 
     
    
    
     DESCRIPTION OF NOTATIONS 
     
         
           1  bill processing apparatus 
           2  apparatus main body 
           3  bill traveling route 
           5  bill insertion slot 
           6  bill conveyance mechanism 
           8  bill reading means 
           10  skew correction mechanism 
           80   a  first light emitting part 
           81  light receiving/emitting unit 
           81   a  light receiving part 
           81   b  second light emitting part 
           200  control means 
       
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 
       FIGS. 1 to 5  are diagrams showing a configuration of a bill processing apparatus according to this embodiment.  FIG. 1  is a perspective view showing a general configuration thereof;  FIG. 2  is a perspective view showing a state that an open/close member is opened for a main body frame of an apparatus main body; FIG.  3  is a right side view showing schematically a traveling route for a bill inserted from an insertion slot;  FIG. 4  is a right side view showing schematically a power transmission mechanism for driving a presser plate installed in a bill housing part; and  FIG. 5  is a left side view showing a schematic configuration of a driving source and a driving force transmission mechanism to drive a bill conveyance mechanism. 
     A bill processing apparatus  1  of this embodiment is so configured that it can be incorporated into, for example, various types of gaming machines such as a slot machine and the like, and the bill processing apparatus  1  includes an apparatus main body  2  and a housing part (e.g., stacker or cashbox)  100  which is provided to the apparatus main body  2  and is capable of stacking and housing a great number of bills. Here, the housing part  100  may be mountable to and demountable from the apparatus main body  2 , and it is possible, for example, to remove it from the apparatus main body  2  by pulling a handle  101  provided on the front face thereof in a state that a lock mechanism (not shown) is unlocked. 
     As shown in  FIG. 2 , the apparatus main body  2  has a main frame body  2 A and an open/close member  2 B being configured to be opened and closed for the main body frame  2 A by rotating around an axis positioned at one end thereof as a rotating center. Then, as shown in  FIG. 3 , the frame  2 A and the open/close member  2 B are configured to form a space (bill traveling route  3 ) through which a bill is conveyed such that both face each other across the space when the open/close member  2 B is closed for the main body frame  2 A, and to form a bill insertion slot  5  such that front exposed faces of both are aligned and that the bill traveling route  3  exits at the bill insertion slot  5 . In addition, the bill insertion slot  5  is a slit-like opening from which a short side of a bill can be inserted into the inside of the apparatus main body  2 . 
     Also, in the apparatus main body  2 , a bill conveyance mechanism  6  that conveys a bill along a bill traveling route  3 ; an insertion detecting sensor  7  that detects the bill inserted into the bill insertion slot  5 ; bill reading means  8  that is installed on a downstream side of the insertion detecting sensor  7  and reads out information on the bill in a traveling sate; a skew correction mechanism  10  that accurately positions and conveys the bill with respect to the bill reading means  8 ; a movable piece passage detecting sensor  12  that detects that the bill passes through a pair of movable pieces constituting the skew correction mechanism; and a discharge detecting sensor  18  that detects that the bill is discharged into a bill housing part  100  are provided. 
     Hereafter, the respective components described above will be described in detail. The bill traveling route  3  extends from the bill insertion slot  5  toward the inside, and comprises a first traveling route  3 A and a second traveling route  3 B extending from the first traveling route  3 A toward the downstream side and being inclined downwardly at a predetermined angle to the first traveling route  3 A. The second traveling route  3 B is bent in a vertical direction on the downstream side and a discharge slot  3   a  from which the bill is discharged into the bill housing part  100  is formed at an end portion on the downstream side such that the bill discharged from the discharge slot  3   a  is fed into a feed port (receiving port)  103  of the bill housing part  100  in the vertical direction. 
     The bill conveyance mechanism  6  is a mechanism capable of conveying the bill inserted from the bill insertion slot  5  along the insertion direction, and of conveying back the bill in an insertion state toward the bill insertion slot  5 . The bill conveyance mechanism  6  comprises a motor  13  (refer to  FIG. 5 ) serving as a driving source installed in the apparatus main body  2 ; and conveyor roller pairs ( 14 A and  14 B), ( 15 A and  15 B), ( 16 A and  16 B), and ( 17 A and  17 B) which are installed with predetermined intervals along the bill traveling direction in the bill traveling route  3 , and are driven to rotate by the motor  13 . 
     The conveyor roller pairs are installed so as to be partially exposed on the bill traveling route  3 , and all the pairs are constituted of driving rollers of the conveyor rollers  14 B,  15 B,  16 B, and  17 B installed on the underside of the bill traveling route  3  driven by the motor  13 ; and pinch-rollers of the conveyor rollers  14 A,  15 A,  16 A, and  17 A installed on the upperside and driven by the these driving rollers. In addition, the conveyor roller pair ( 14 A and  14 B) to first nip and hold therebetween the bill inserted from the bill insertion slot  5 , and to convey the bill toward the back side, as shown in  FIG. 2 , is installed in one portion of the center position of the bill traveling route  3 , and a couple of the conveyor roller pairs ( 15 A and  15 B), ( 16 A and  16 B), or ( 17 A and  17 B) being disposed in this order on the downstream side thereof are respectively installed in a couple of portions with a predetermined interval in the lateral direction of the bill traveling route  3 . 
     Further, the conveyor roller pair ( 14 A and  14 B) disposed in the vicinity of the bill insertion slot  5  is usually in a state that the upper conveyor roller  14 A is spaced from the lower conveyor roller  14 B, and the upper conveyor roller  14 A is driven to move toward the lower conveyor roller  14 B to nip and hold the inserted bill therebetween when insertion of the bill is detected by the insertion detecting sensor  7 . 
     Thus, the upper conveyor roller  14 A is controllably driven to be pressed against or spaced from the lower conveyor roller  14 B by a motor  70  (refer to  FIG. 6 ) for an up-and-down movement of the roller as a driving source. In this case, when a process (skew correction process) for positioning the bill with respect to the bill reading means  8  by eliminating inclination of the inserted bill is executed by the skew correction mechanism  10 , the upper conveyor roller  14 A is spaced from the lower conveyor roller  14 B so as to release the load on the bill, and when the skew correction process is completed, the upper conveyor roller  14 A is driven to move toward the lower conveyor roller  14 B again to hold (or nip) the bill therebetween. Here, the driving source may be constituted of a solenoid or the like instead of a motor. 
     Further, the skew correction mechanism  10  comprises a pair of right and left movable pieces  10 A (only one side is shown) such that the pair of right and left movable pieces  10 A are moved to get closer with each other by driving a motor  40  for a skew driving mechanism, whereby the skew correction process is performed for the bill. 
     The conveyor rollers  14 B,  15 B,  16 B and  17 B installed on the underside of the bill traveling route  3  are, as shown in  FIG. 5 , driven to rotate via the motor  13  and pulleys  14 C,  15 C,  16 C, and  17 C installed at the ends of the driving shafts of the respective conveyor rollers. That is, a driving pulley  13 A is installed on the output shaft of the motor  13 , and a driving belt  13 B is wrapped around between the pulleys  14 C,  15 C,  16 C, and  17 C installed at the ends of the driving shafts of the respective conveyor rollers and the driving pulley  13 A. In addition, tension pulleys are engaged in places with the driving belt  13 B, which prevents the driving belt  13 B from loosening. 
     In accordance with the configuration described above, when the motor  13  is driven to normally rotate, the conveyor rollers  14 B,  15 B,  16 B, and  17 B are driven to normally rotate in synchronization therewith to convey the bill toward the insertion direction. When the motor  13  is driven to reversely rotate, the conveyor rollers  14 B,  15 B,  16 B, and  17 B are driven to reversely rotate in synchronization therewith to convey back the bill toward the bill insertion slot  5  side. 
     The insertion detecting sensor  7  is to generate a detection signal when a bill inserted into the bill insertion slot  5  is detected. And when the detection signal is generated, the motor  13  is driven in a normal direction and the bill is conveyed in the insertion direction. The insertion detecting sensor  7  of this embodiment is installed between the pair of conveyor rollers ( 14 A and  14 B) and the skew correction mechanism  10  and comprises, for example, an optical sensor such as a regressive reflection type photo sensor. However, the insertion detecting sensor  7  may comprise a mechanical sensor other than the optical sensor. 
     Further, the movable piece passage detecting sensor  12  is to generate a detection signal when it is detected that a front end of the bill passes through a pair of right and left movable pieces  10 A constituting the skew correction mechanism  10 , and when the detection signal is generated, the driving by the motor  13  is stopped such that the skew correction is made. The movable piece passage detecting sensor  12  of this embodiment is disposed on the upstream side from the bill reading means  8  and also comprises an optical sensor or a mechanical sensor in the same way as mentioned before with respect to the insertion detecting sensor. 
     Further, the discharge detecting sensor  18  is to detect a trailing end of the bill passing through such that it is detected that the bill is discharged into the bill housing part  100 . The discharge detecting sensor  18  is disposed just in front of the receiving port  103  of the bill housing part  100  on the downstream side of the second traveling route  3 B. When the detection signal is transmitted from the discharge detecting sensor  18 , the driving by the motor  13  is stopped and the conveyance processing of the bill is terminated. The discharge detecting sensor  18  also comprises an optical sensor or a mechanical sensor in the same way as the aforementioned insertion detecting sensor. 
     The bill reading means  8  reads bill information on the bill conveyed in a state that the skew is eliminated by the skew correction mechanism  10 , and determines the validity (authenticity). In this embodiment, the bill reading means  8 , which is installed in the above-mentioned first traveling route  3 A, comprises a line sensor which irradiates the bill being conveyed from top and bottom sides thereof with light such that a transmitted light and a reflected light thereof are detected by a light receiving part so as to perform reading. 
     Here, the configuration of above-mentioned reading means  8  will be described in detail with reference to  FIGS. 2 and 3 . 
     The abovementioned bill reading means  8  has a light emitting unit  80  which is installed on the side of the open/close member  2 B and provided with a first light emitting part  80   a  capable of irradiating the upper side of the bill to be conveyed with the infrared light and the red light, and a light receiving/emitting unit  81  which is installed on the side of the main body frame  2 A. 
     The light receiving/emitting unit  81  has a light receiving part  81   a  which is provided with a light receiving sensor facing the first light emitting part  80   a  across the bill (bill traveling route) and second light receiving parts  81   b  which are installed adjacently on the both sides of the light receiving part  81   a  along the bill traveling direction and are capable of irradiating the object with the infrared light and the red light. 
     The first light emitting part  80   a  disposed to face the light receiving part  81   a  works as a light source for the transmissive light. This first light emitting part  80   a  is, as shown in  FIG. 2 , comprised of a rectangular bar-like body made of synthetic resin which emits the light guided through a light guiding body  80   c  provided inside from an LED element  80   b  fixed to one end of the bar-like body. The first light emitting part having such a configuration is linearly installed in parallel with the light receiving part  81   a  (light receiving sensor) so as to be capable of entirely and equally irradiating the entire (or whole) range in the width direction of the traveling route of the bill to be conveyed although the configuration is simple. 
     The light receiving part  81   a  of the light receiving/emitting unit  81  is formed in a thin-walled plate shape having a band shape extending in a lateral direction of the bill traveling route  3  and having a width to an extent that the sensitivity of the light receiving sensor (not shown) provided in the light receiving part  81   a  is not affected. In addition, the light receiving sensor is configured as a so-called line sensor in which a plurality of CCDs (Charge Coupled Devices) are provided linearly at the center in the thickness direction of the light receiving part  81   a , and a GRIN lens array  81   c  is disposed linearly above these CCDs so as to collect the transmitted light and the reflected light. 
     The second light emitting part  81   b  of the light receiving/emitting unit  81  works as a light source for the reflection light. This second light emitting part  81   b  is, in a similar manner as the first emitting part  80   a , comprised of a rectangular bar-like body made of synthetic resin which emits the light guided through a light guiding body  81   e  provided inside from an LED element  81   d  fixed to one end of the bar-like body. The second light emitting part  81   b  is also configured to be linearly installed in parallel with the light receiving part  81   a  (line sensor). 
     The second light emitting parts  81   b  are capable of irradiating the bill with the light at an elevation angle of 45 degrees, for example, and are so installed that the light receiving part  81   a  may receive the reflected light from the bill. In this case, the lights irradiated to the bill by the second light emitting parts  81   b  are to be made incident at 45 degrees onto the light receiving part  81   a , but the incident angle is not limited to 45 degrees such that the arrangement may be re-arranged as appropriate as long as the lights are irradiated evenly to the surface of the bill. Therefore, the arrangement of the second light emitting parts  81   b  and the light receiving part  81   a  may be appropriately changed in design in accordance with the structure of the bill processing apparatus. 
     Further, the second light emitting parts  81   b  are disposed on the both sides of the light receiving part  81   a  so as to be disposed across the light receiving part  81   a  and irradiate the bill with the respective lights at respective incident angles of 45 degrees. This is because, in the case where the surface of the bill has scratches or folded wrinkles, and in the case where the light is irradiated only from one side to an uneven surface generated by these scratches or folded wrinkles, it is unavoidable to make some portions shaded to cause shadow in the uneven surface. Therefore, it is prevented that the shadow is made in the portion of the uneven surface by irradiating the bill with the lights from the both sides, whereby the image data to be acquired can have a higher degree of accuracy than that of the single side irradiation. As a matter of course, the apparatus may comprise only one second light emitting part  81   b  installed on either side, and the configuration, the arrangement, and the like of the light emitting unit  80  and the light receiving/emitting unit  81  as described above are not limited to those described in this embodiment, and may be modified as appropriate. 
     An authenticity judgment process is conducted by comparing image data obtained by reflected light (irradiated light by the second light emitting part  81   b ) and transmitted light (irradiated light by the first light emitting part  80   a ) from the bill which are acquired by the above-mentioned light receiving part  81   a  with the image data of the legitimate bill. In this case, since the legitimate bill has some area from which different image data are acquired depending on the wavelengths of the lights (for example, visible light or infrared light) irradiated to the area, in the authenticity judgment process in this embodiment, a plurality of light sources, in consideration of this view point, irradiate different lights of different wavelengths (in this embodiment, a red light and an infrared light are irradiated) to the bill and a transmitted light therethrough and a reflected light thereon are detected such that the authenticity identification accuracy may be improved. That is, since the red light and the infrared light have different wavelengths, transmitted-light data and reflected-light data from a plurality of lights of different wavelengths may be utilized for the bill authenticity judgment whereby the judgment may use the nature that the transmittance of the transmitted light transmitted through the specific area and the reflectance of the reflected light reflected on the specific area in the legitimate bill are different from those of the counterfeit bill. Therefore, in the above-mentioned light emitting part (first light emitting part  80   a  and second light emitting part  81   b ), an attempt is made to further improve the bill authenticity identification accuracy by employing light sources where a plurality of wavelengths are available. 
     Here, since it is possible to acquire various kinds of received-light data (transmitted-light data and reflected-light data) depending on the wavelengths of the irradiated lights to the bill and the irradiated areas of the bill, although a concrete bill authenticity identification method will not be written in detail, the image appears greatly different depending on the lights in a watermark area of the bill, for example, if an image on the area is viewed with the lights of different wavelengths. Therefore, it can be considered that the bill to become an identification object is identified as the legitimate bill or the counterfeit bill by setting this portion as the specified area, acquiring transmitted-light data and reflected-light data from the specified area, and comparing such data with legitimate data from the same specified area of the legitimate bill having been stored in advance in storage means such as ROM. At this time, provided that specified areas are predetermined according to the kinds of the bills, and that predetermined weighting may be applied to the transmitted-light data and the reflected-light data from this specified area, the authenticity identification accuracy may be improved. 
     In addition, the above-mentioned light emitting part (first light emitting part  80   a  and second light emitting part  81   b ) is controlled to light with a predetermined interval and transmitted light and reflected light are detected by the light receiving part (line sensor)  81   a  when the bill passes. The light receiving part (line sensor)  81   a  can acquire contrasting density data (a plurality of pixel data per a predetermined size as a unit which include brightness) in accordance with the brightness and it is also possible to generate two-dimensional image from such pixel data. 
     That is, the pixel data acquired by the line sensor is converted into data including color information having brightness for each pixel by a converter which will be described later. Here, the color information of each pixel having brightness to be converted by the converter is what is represented by a numerical value from 0 to 255 (e.g., 0: black to 255: white) assigned to each pixel according to the brightness. 
     Therefore, in the authenticity judgment process as described above, the predetermined area of the bill may be extracted; the color information per each pixel having brightness included in the area and color information per each pixel having brightness of the same area of a legitimate bill may be used; then a coefficient of correlation is calculated by an appropriate correlation formula as such information is plugged therein; and it is possible to identify the authenticity of the bill by the coefficient of correlation. Or, in addition to the above description, analog waveforms, for example, may be generated from the transmitted-light data and the reflected-light data, and the respective shapes of those waveforms may be compared with each other, whereby the authenticity identification may be conducted by such comparison. Moreover, a process in which the length of a printing area of the bill is detected and the authenticity thereof is identified by utilizing the length information, may also be provided. 
     Before executing the above authenticity judgment process, a predetermined area is set up in a bill to be inserted. With regard to the predetermined area, comparison is made between a transmitted image consisting of multiple pixels converted by a converter from the transmitted light received by the light receiving part  81   a  and a reflected image consisting of multiple pixels converted by the converter from the reflected light received by the light receiving part  81   a  and, based on the comparison results, a process of excluding the predetermined area from the authenticity judgment (the authenticity judgment exclusion process) is executed. 
     The authenticity judgment exclusion process will be described hereafter. 
     As described above, in the bill authenticity judgment process, a conveyed bill is irradiated with light from the light emitting part and the transmitted light and reflected light are received by the light receiving part, photoelectrically-converted, and converted by the converter to image date (transmitted image data and reflected image data) containing color information including brightness on the basis of pixels. The information of each pixel converted by the converter corresponds to brightness (luminance value) and a value ranging from 0 to 255 (for example, 0 for black and 255 for white) is assigned to each pixel according to the brightness. This is compared with the pixel data regarding legitimate bills and stored in advance. 
     Therefore, when a bill inserted by the user has some state change (mainly being wet or pierced), the transmitted image data present higher brightness than the reflected image data in the part having the state change (pixels have higher brightness). In this regard, the transmitted image data do not present higher brightness than the reflected image data if a bill does not have such state change. Therefore, a bill having such state change is identified as a forged bill as a result of comparison with pixel data regarding legitimate bills in the conventional authenticity judgment process. 
     In other words, when a bill has some state change such as being wet or pierced, even a legitimate bill may be identified as a forged bill as a result of comparison on the conditionally changed part, which may cause some inconvenience to the user. 
     Therefore, in the present invention, a predetermined area is set up on the bill to be inserted in advance and, even if the bill has the above-described state change on that part, the bill is not immediately assumed to be a forged bill and other parts are used for comparison in the authenticity judgment process. In other words, the pixel data of a predetermined area are acquired and, if the transmitted image data present higher brightness than the reflected image data in the predetermined area, it is assumed that the bill simply has some state change; then, the authenticity judgment process is conducted for other areas. 
     In this regard, it is assumed that the bill simply has some state change as a result of comparison between the transmitted image data and reflected image data of a predetermined area, for example, when the following mathematical equation (Equation 1) is satisfied provided that numerical values 0 to 255 (0 for black and 255 for white) are assigned according to the brightness of the pixels of the transmitted image data and reflected image data.
 
Σ aij −Σ bij ≧0  [Formula 1]
 
     Here, a is a numerical value assigned to a pixel of the transmitted image and (i, j) are the coordinates on the bill. A predetermined area is defined using the coordinates in advance and the total value of the pixels of the transmitted image of the predetermined area is derived. On the other hand, b is a numerical value assigned to a pixel of the reflected image and the total value of the pixels of the reflected image of the predetermined area is similarly derived. 
     As in the above mathematical equation, if the total (or possibly average) brightness of the transmitted image is higher than that of the reflected image in a predetermined area, it is assumed that the transmitted image is brighter in the predetermined area and some state change (being wet or pierced) has occurred; then, the predetermined area is excluded from the actual authenticity judgment process. 
     In this embodiment, the above predetermined area is set up in an area other than areas where irradiation with light of different wavelengths from a light emitting part leads to different image information (such an area is termed a characteristic area). In other words, since the areas where irradiation with light of different wavelengths from a light emitting part (a first light emitting part  80   a  and a second light emitting part  81   b ) leads to different image information are considered to be important for the actual bill authenticity judgment, other areas are excluded from the actual authenticity judgment as the above predetermined area. For this reason, if the total (or possibly average) brightness of the transmitted image is higher than that of the reflected image in a characteristic area, that characteristic area is not excluded from the authenticity judgment process. 
     This is because it is less likely that the above state change in a non-characteristic area (a predetermined area) particularly affects the authenticity judgment. Such non-characteristic areas are assigned to the above predetermined area so as to prevent reduction in the accuracy of authenticity judgment. 
     Here, the above characteristic areas of a bill can be, for example, areas where a watermarked image is formed. Furthermore, in the event that a characteristic area of a bill is wet, in other words that the total (or possibly average) brightness of the transmitted image is higher than that of the reflected image in a characteristic area, the bill can immediately be discharged. 
     Then, in the actual authenticity judgment process, comparison is made between reference pixel data regarding a legitimate bill and stored in advance in a ROM and the like and pixel data obtained by irradiating the printed area on the surface of a conveyed bill with light of a given wavelength from a light emitting part (a first light emitting part  80   a  and a second light emitting part  81   b ) and consisting of the transmitted light data from light transmitted through the bill and the reflected light data from light reflected by the bill. As described above, even if the above equation is satisfied for the predetermined area at the previous step to the authenticity judgment process, it is assumed that the state change has occurred to a legitimate bill and the predetermined area is excluded from the comparison with reference data (reference data from which the predetermined area is excluded in advance) in the actual authenticity judgment process. 
     Next, the bill housing part  100  that stacks and houses sequentially bills thus-identified authentic by the bill reading means  8  will be explained. 
     As shown in  FIGS. 3 to 5 , the main body frame  100 A constituting the bill housing part  100  is formed into a substantially rectangular parallelepiped (or cuboid) shape, and one end of bias means (e.g., bias spring)  106  is attached to an interior side of a front wall  102   a  thereof, and a placing plate  105  on which bills to be fed via the above-described receiving port  103  are sequentially stacked is provided to the other end thereof. Therefore, the placing plate  105  is in a state that it is pressed toward the presser plate  115 , which will be described later, by the bias means  106 . 
     In the main body frame  100 A, a press standby part  108  that keeps a dropping bill as it falls is provided so as to continuously communicate with the receiving port  103 . A pair of regulatory members  110  are disposed on both sides of the press standby part  108 , respectively, the regulatory members  110  extending in a vertical direction. An opening is formed between the pair of regulatory members  110  such that the presser plate  115  passes through the opening as bills are successively stacked onto the placing plate  105 . 
     Further, the presser plate  115  that presses toward the placing plate  105  a bill falling into the press standby part  108  from the receiving port  103  is installed in the main body frame  100 A. The presser plate  115  is formed in such a size that it may be capable of reciprocating through an opening formed between the pair of regulatory members  110 , and gets into the opening so as to be driven to reciprocate between a position where the bills are pressed against the placing plate  105  (a pressing position) and another position where the press standby part  108  is opened (an initial position). In this case, the bill passes through the opening as being flexibly bent in a pressing operation of the presser plate  115  and is then placed on the placing plate  105 . 
     The presser plate  115  is driven to reciprocate as described above via a presser plate driving mechanism  120  installed in the main body frame  100 A. The presser plate driving mechanism  120  comprises a pair of link members  115   a  and  115   b  having respective ends thereof supported pivotally by the presser plate  115  so as to allow the presser plate  115  to reciprocate in an arrow A direction in  FIGS. 3 and 4 , and these link members  115   a  and  115   b  are connected in a shape of letter “X”, and the other ends opposite to the respective ends are supported pivotally by a movable member  122  installed movably in a vertical direction (an arrow B direction). A rack is formed in the movable member  122 , and a pinion constituting the presser plate driving mechanism  120  is geared (engaged) with the rack. 
     As shown in  FIG. 4 , a housing part side gear train  124  constituting the presser plate driving mechanism  120  is connected to the pinion. For this case, as shown in  FIG. 4 , in this embodiment, a driving source (a motor  20 ) and a main body side gear train  21  sequentially engaged with the motor  20  are installed in the above-described apparatus main body  2 , and when the bill housing part  100  is mounted to the apparatus main body  2 , the main body side gear train  21  is to be connected to the housing part side gear train  124 . That is, the housing part side gear train  124  comprises a gear  124 B installed on the same axis of the pinion and gears  124 C,  124 D to be engaged sequentially with the gear  124 B, and when the bill housing part  100  is mounted to and demounted from the apparatus main body  2 , the gear  124 D is configured to be engaged with and disengaged from a final gear  21 A of the main body side train  21 . 
     As a result therefrom, the presser plate  115  is driven to reciprocate in the arrow A direction as the motor  20  installed in the apparatus main body  2  is driven to rotate so as to drive the main body side train  21  and in turn the presser plate driving mechanism  120  (the housing part side gear train  124 , the rack installed onto the movable member  122 , and the link members  115   a ,  115   b , etc.). 
     Conveyor members  150  which are capable of touching the bill conveyed-in from the receiving port  103  are installed in the main body frame  100 A. The conveyor members  150  take their own role to contact the bill conveyed-in so as to stably guide the bill to an appropriate position in the press standby part  108  (position where the bill can be stably pressed without causing the bill to be moved to the right or left side when the bill is pressed by the presser plate  115 ). In this embodiment, the conveyor members are constituted of belt-like members (hereafter called belts  150 ) installed so as to face the press standby part  108 . 
     In this case, the belts  150  are installed so as to extend along the conveying-in direction with respect to the bill, and are wrapped around the pair of pulleys  150 A and  150 B supported rotatably on both ends in the conveying-in direction. Further, the belts  150  contact a conveyor roller  150 C extending in an axis direction which is supported rotatably in the region of the receiving port  103 , and the belts  150  and the conveyor roller  150 C nip and hold the bill conveyed-in the receiving port  103  therebetween to guide the bill directly to the press standby part  108 . Moreover, in this embodiment, the pair of belts  150  are provided on the right and left sides, respectively, across the above-described presser plate  115  in order to be capable of contacting the surface on left and right sides of the bill. Here, the belts  150  may be prevented from loosening by not only being wrapped around the pulleys  150 A and  150 B at the both ends, but also causing tension pulleys to push the belts  150  at the intermediate positions, respectively. 
     The pair of belts  150  are configured to be driven by the motor  13  that drives the above-described plurality of conveyor rollers installed in the apparatus main body  2 . In detail, as shown in  FIG. 5 , the above-described driving belt  13 B driven by the motor  13  is wrapped around a pulley  13 D for the driving force transmission, and a gear train  153  installed at the end of the spindle of the pulley  150 A supported rotatably on the receiving port  103  side is engaged with a gear train  13 E for the power transmission sequentially installed onto the pulley  13 D. That is, when the bill housing part  100  is mounted to the apparatus main body  2 , an input gear of the gear train  153  is configured to be engaged with a final gear of the gear train  13 E, and the pair of belts  150  are configured to be driven to rotate in a synchronized manner with the above-described conveyor rollers  14 B,  15 B  16 B, and  17 B for conveying the bill by driving the motor  13  to rotate. 
     As described above, when the bill is inserted into the inside via the bill insertion slot  5 , the bill is moved inside the bill traveling route  3  by the bill conveyance mechanism  6 . The bill traveling route  3  is extended from the bill insertion slot  5  toward the back side, as shown in  FIG. 3 , and comprises a first traveling route  3 A and a second traveling route  3 B which is extended from the first traveling route  3 A toward downstream side and is inclined at a predetermined angle to the first traveling routes  3 A. 
     Further, a pull-out preventing member (shutter member)  170  that prevents the bill from being conveyed toward the bill insertion slot  5  is installed in the second traveling route  3 B. The pull-out preventing member  170  is biased to rotate in the arrow direction of  FIG. 3  (a direction in which the second traveling route  3 B is closed) via a spindle  170   a , and when the bill moves toward the side of the bill housing part  100 , the pull-out preventing member  170  is rotated so as to open the second traveling route against the biasing force, and when the bill once passes through the second traveling route, the pull-out preventing member  170  is rotated in the arrow direction to close the second traveling route  3 B. That is, when the rear end of the bill passes through the pull-out preventing member  170 , the second traveling route  3 B is closed by the pull-out preventing member  170 , not to allow the bill to be drawn out. 
     In addition, such pull-out preventing members may be installed at a plurality of places along the traveling route on the downstream side of the bill reading means  8 . Further, their installing positions may be on the side downstream from the position at which the bill is stopped at the time of carrying out the bill authenticity judgment process (an escrow position; a position on the downstream side by approximately 13 mm from the bill reading means  8  in this embodiment). 
     Next, control means  200  that controls the driving of the bill conveyance mechanism  6 , the bill reading means  8  and the like as mentioned above will be described with reference to a block diagram of  FIG. 6 . 
     The control means  200  as shown in a block diagram of  FIG. 6  comprises a control board  210  which controls the operations of the above-described respective drive units, and a CPU (Central Processing Unit)  220  controlling driving of each drive unit and constituting the bill identification means, a ROM (Read Only Memory)  222 , a RAM (Random Access Memory)  224 , and an authenticity judging part  230  are implemented on the control board  210 . 
     In the ROM  222 , permanent data such as various types of programs such as a multi-feed judging program for judging a double feed or a folded feed at a leading end portion of the bill; an authenticity judgment program by the authenticity judging part  230 , operation programs for the respective drive units such as the motor  13  for the bill conveyance mechanism, the motor  20  for the presser plate, the motor  40  for the skew correction mechanism, and the roller up-and-down motor  70  for lifting up and down rollers; and the like are stored. 
     The CPU  220  operates according to the programs stored in the ROM  222 , and carries out input and output of the signals with respect to the respective drive units described above via an I/O port  240 , so as to perform the entire operational control of the bill processing apparatus. That is, the motor  13  for the bill conveyance mechanism, the motor  20  for the presser plate, the motor  40  for the skew correction mechanism, and the roller up-and-down motor  70  are connected to the CPU  220  via the I/O port  240 , and the operations of these drive units are controlled by control signals transmitted from the CPU  220  in accordance with the operation programs stored in the ROM  222 . Further, the CPU  220  is so configured that detection signals from the insertion detecting sensor  7 , the movable piece passage detecting sensor  12 , and the base part detecting sensor  18  are input into the CPU  220  via the I/O port  240 , and the driving of the respective drive units is controlled based on these detection signals. 
     Moreover, the CPU  220  is so configured that a detection signal based on the transmitted light and the reflected light of the light which is irradiated to the bill as the identification object is input into the CPU  220  via the I/O port  240  from the light receiving part  81   a  in the bill reading means  8  as described. The first light emitting part  80   a  and the second light emitting parts  81   b  in the bill reading means  8  are controlled through a light emission control circuit  260  by a control signal from the CPU  220  in accordance with the operation programs stored in the abovementioned ROM  222  such that the lighting interval and the turning-off are controlled. 
     The RAM  224  temporarily stores data and programs used for the CPU  220  to operate, and also acquires and temporarily stores the received light data of the bill serving as the identification object. Furthermore, the RAM  224  stores transmitted image data consisting of multiple pixels converted by a converter  231  described later from the transmitted light received by the light receiving part  81   a  and reflected image data consisting of multiple pixels converted by the converter  231  from the reflected light received by the light receiving part  81   a.    
     The authenticity judgment processing part  230  judges whether the conveyed bill is illegitimate. The authenticity judgment processing part  230  comprises a converter  231  converting the received light data of an identification object that are stored in the RAM  224  to pixel information containing color information (density value) including brightness on the basis of pixels, an image data processing part  232  acquiring image data based on the pixel information converted by the converter  231 , and a determining part  233  comparing the brightness of the pixels of the transmitted image of the above predetermined area with the brightness of the pixels of the reflected image corresponding to the predetermined area of the transmitted image and, based on the comparison results, excluding the predetermined area from the authenticity judgment. Therefore, when the determining part  233  determines that the brightness of the transmitted image of the predetermined area is higher than the brightness of the reflected image of the same predetermined area based on the above mathematical equation, the image data processing part  232  receives image data from which the image data from the transmitted light and image data from the reflected light that are obtained in the predetermined area are excluded. 
     Further, the bill determination processing part  230  comprises: a reference data storage part  234  in which the reference data of the legitimate bill (pixel data of the legitimate bill) is stored, and a comparison judgment part  235  which compares the image data (pixel data) of the bill acquired by the image data processing part  232  with the reference data (reference pixel data) stored in the reference data storage part  234 , and carries out the determination process to determine whether the bill being conveyed is legitimate or not. 
     In this case, the reference data storage part  234  stores image data about the legitimate bill to be used, when the above-mentioned authenticity judgment process is carried out, and image data relating the legitimate bill excluding the predetermined area as mentioned above. In other words, although reference data include image data of a predetermined area in the conventional authenticity judgment process, the determining part  233  uses the reference data consisting of image data excluding the predetermined area when the predetermined area is excluded. The reference data storage part  234  further stores various reference data used for the authenticity judgment on the basis of money classes such as reference values on print lengths regarding legitimate bills. 
     Here, data which can be the reference data is stored in the dedicated reference data storage part  234 . However, the data may be stored in the above-mentioned ROM  222 . 
     The actual authenticity judgment process in the above-mentioned authenticity judgment processing part  230  is performed by irradiating a printing area on the surface of the bill being conveyed with light of a predetermined wavelength from the light emitting part (first light emitting part  80   a  and second light emitting part  81   b ), converting the reflected light data of the light reflected and the transmitted light data of the light transmitted from the bill into a plurality of pixel data having the brightness data per a predetermined size as the unit in the converter  231 , and comparing such data with the reference pixel data of the legitimate bill stored in advance with the reference data storage part  234 . In addition, when the determining part  233  determines that the state change is made in the predetermined area of the bill as described above, the authenticity judgment process is executed as the image data of the bill excluding the predetermined areas is acquired. 
     Next, the bill processing operation in the bill processing apparatus  1  executed by the control means  200  will be described according to the flowcharts of  FIGS. 7 to 13 . 
     When an operator inserts a bill into the bill insertion slot  5 , the conveyor roller pair ( 14 A and  14 B) installed in the vicinity of the bill insertion slot is in a state that the rollers are spaced from each other in an initial stage (refer to ST 18  and ST 58  to be described later). Further, with respect to the presser plate  115 , the pair of link members  115   a  and  115   b  driving the presser plate  115  are located at the press standby part  108 , and the presser plate  115  is positioned in the standby position such that the bill cannot be conveyed-in the press standby part  108  from the receiving port  103  by the pair of link members  115   a  and  115   b . That is, in this state, the presser plate  115  is brought into the opening formed between the pair of regulatory members  110  such that the condition is so made as to prevent the bills stored in the bill housing part from being drawn out through the opening. 
     Moreover, the pair of movable pieces  10 A constituting the skew correction mechanism  10  located on the downstream side of the conveyor roller pair ( 14 A,  14 B) are in a state that the pair of movable pieces  10 A are moved to leave the minimum open width therebetween (for example, an interval between the pair of movable pieces  10 A is 52 mm; refer to ST 15  and ST 57  to be described later) so as to prevent the bill from being drawn out in the initial stage. 
     In the initial state of the above-described pair of conveyor rollers ( 14 A and  14 B), it is possible for the operator to easily insert even a bill having wrinkles into the paper sheet insertion slot  5 . Then, when insertion of the bill is detected by the insertion detecting sensor  7  (ST 01 ), the driving motor  20  of the above-described presser plate  115  is driven to rotate reversely for a predetermined amount (ST 02 ) to move the presser plate  115  to the initial position. That is, the presser plate  115  is in a state that the presser plate  115  is moved and remains in the opening formed between the pair of regulatory members  110  such that it is so arranged that the bill cannot pass through the opening until the insertion of another bill is detected by the insertion detecting sensor  7 . 
     When the presser plate  115  is moved from the standby position to the initial position, the press standby part  108  becomes in an open state (refer to  FIG. 4 ) such that the apparatus is in a state that the bill can be conveyed into the bill housing part  100 . That is, by driving the motor  20  to rotate reversely for a predetermined amount, the presser plate  115  is moved from the standby position to the initial position via the main body side gear train  21  and the presser plate driving mechanism  120  (the housing part side gear train  124 , the rack formed on the movable member  122 , and the link members  115   a ,  115   b ). 
     Further, the above-described roller up-and-down motor  70  is driven to move the upper conveyor roller  14 A so as to make a contact with the lower conveyor roller  14 B. In accordance therewith, the inserted bill is nipped and held therebetween by the pair of conveyor rollers ( 14 A and  14 B) (ST 03 ). 
     Next, a traveling route opening process is conducted (ST 04 ). The opening process is conducted by driving the pair of movable pieces  10 A to move in separating directions so as to become apart with each other as the motor  40  for the skew correction mechanism is driven to rotate reversely as shown in the flow chart of  FIG. 10  (ST 100 ). At this time, when it is detected that the pair of movable pieces  10 A have moved to the predetermined positions (the maximum open width positions) by the movable piece detecting sensor (ST 101 ), the driving operation to rotate the motor  40  reversely is stopped (ST 102 ). This traveling route opening process makes the skew correction mechanism in such a condition as to allow the paper sheet to enter between the pair of movable pieces  10 A. In addition, in the previous step of ST 04 , the bill traveling route  3  is in a closed state by a traveling route closing process (ST 15 , ST 57 ) to be described later. Thus, the bill traveling route  3  is closed in this way before an insertion of the bill so as to prevent an element such as a line sensor from being broken by, for example, inserting a plate-like member from the bill insertion slot for illicit purposes or the like. 
     Next, the bill conveyor motor  13  is driven to rotate normally (ST 05 ). The bill is conveyed into the inside of the apparatus by the conveyor roller pair ( 14 A and  14 B), and when the movable piece passage detecting sensor  12  installed on the downstream side from the skew correction mechanism  10  detects the leading end of the bill, the bill conveyor motor  13  is stopped (ST 06  and ST 07 ). At this time, the bill is located between the pair of movable pieces  10 A constituting the skew correction mechanism  10 . 
     Subsequently, the above-described roller up-and-down motor  70  is driven to allow the conveyor roller pair ( 14 A and  14 B) holding the bill therebetween to become apart from each other (ST 08 ). At this time, the bill is in a state that no load is applied. 
     Then, a skew correction operating process is executed as the paper sheet remains in this state (ST 09 ). The skew correction operating process is conducted by driving the motor  40  for the skew correction mechanism to rotate normally to drive the pair of movable pieces  10 A to get closer with each other. That is, in this skew correction operating process, as shown in the flowchart of  FIG. 11 , the motor  40  described above is driven to rotate normally to move the pair of movable pieces  10 A in respective directions such that the pair of movable pieces  10 A get closer with each other (ST 110 ). The movement of the movable pieces is continued until the distance therebetween becomes the minimum width (for example; width of 62 mm) of the bill registered in the reference data storage part in the control means. And the skew is corrected by the movable pieces  10 A touching both sides of the bill such that the bill may be positioned at the accurate center position. 
     When the skew correction operating process as described above is completed, a traveling route opening process is subsequently executed (ST 10 ). This process is conducted by moving the pair of movable pieces  10 A in separating directions as the above-described motor  40  for the skew correction mechanism is driven to rotate reversely (refer to ST 100  to ST 102  of  FIG. 10 ). 
     Subsequently, the above-described roller up-and-down motor  70  is driven to move the upper conveyor roller  14 A to contact the lower conveyor roller  14 B, and the bill is nipped and held between the pair of conveyor rollers ( 14 A and  14 B) (ST 11 ). Thereafter, the bill conveyor motor  13  is driven to rotate normally to convey the bill into the inside of the apparatus, and when the bill passes through the bill reading means  8 , a reading process of the bill is executed (ST 12  and ST 13 ). 
     Then, when the bill to be conveyed passes through the bill reading means  8 , and the trailing end of the bill is detected by the movable piece detecting sensor  12  (ST 14 ), a process for closing the bill traveling route  3  is executed (ST 15 ). In this process, first, as shown in the flowchart of  FIG. 12 , after the trailing end of the bill is detected by the movable piece detecting sensor  12 , the above-described motor  40  is driven to normally rotate to move the pair of movable pieces  10 A in the directions that they get closer to each other (ST 130 ). Next, when it is detected by the movable piece detecting sensor that the movable pieces  10 A move to the predetermined positions (minimum open width positions: for example, width of 52 mm) (ST 131 ), the driving operation of the normal rotation of the motor  40  is stopped (ST 132 ). 
     With this traveling route closing process, the pair of movable pieces  10 A are moved to the positions of the minimum open width (width of 52 mm) narrower than the width of any bill allowed to be inserted, thereby effectively preventing the bill from being drawn out. That is, by executing such a bill traveling route closing process, an opening distance between the movable pieces  10 A is made shorter than the width of the inserted bill, thereby enabling the effective prevention of an action of drawing-out the bill in the direction toward the insertion slot by the operator for illicit purposes. 
     In succession to the traveling route closing process described above (ST 15 ), a conveyor roller pair spacing process in which the driving source  70  is driven to allow the conveyor roller pair ( 14 A and  14 B) coming to hold the paper sheet therebetween to be spaced from one another is executed (ST 16 ). By executing the conveyor roller pair spacing process, even if the operator additionally inserts (double insertion) another bill by mistake, the bill is not subject to a feeding operation by the conveyor roller pair ( 14 A and  14 B) and hits front ends of the pair of movable pieces  10 A in a closed state according to ST 15  such that it is possible to reliably prevent the operation of bill double-insertion. 
     Along with the bill traveling route closing process as mentioned above, when the bill reading means  8  reads the data up to the trailing end of the bill, the bill conveyor motor  13  is driven for a predetermined amount and stops the bill in a predetermined position (an escrow position; a position where the bill is conveyed toward the downstream by 13 mm from the center position of the bill reading means  8 ), and at this time, an authenticity judgment process of the bill is executed in the comparison judgment part  234  by referring to the reference data stored in the reference data storage part  233  in the bill determination processing part  230  of the aforementioned control means  200  (ST 17  to ST 20 ). 
     In the authenticity judgment process, first, as shown in the flowchart of  FIG. 13 , the determining part  233  compares the brightness of the pixels of the transmitted image of a predetermined area of a bill with the brightness of the pixels of the reflected image corresponding to the predetermined area of the transmitted image and determines whether the predetermined area has some state change (ST 150 ). This determination is made by comparing the total brightness of the transmitted image of the predetermined area and the total brightness of the reflected image of the same predetermined area based on the above mathematical equation. Then, if it is determined that there is no state change (ST 150 ; No), the image data processing part  232  acquires image data including the predetermined area and the comparison judgment part  235  compares them with the reference data stored in the reference data storage part  234  (ST 152 ). On the other hand, if the determining part  233  determines that the predetermined area has some state change (ST 150 ; Yes), the image data processing part  232  acquires image data excluding the predetermined area (ST 151 ) and the comparison judgment part  235  compares them with the reference data (reference data excluding the predetermined area) stored in the reference data storage part  234  (ST 152 ). 
     Then, in the bill authenticity judgment process at ST 20  as described above, when the bill is judged as a legitimate bill (ST 21 ; Yes), the motor  13  for the bill conveyance is rotated normally (ST 22 ). While the bill is conveyed, the bill conveyor motor  13  is driven to rotate normally until the back end of the bill is detected by the discharge detecting sensor  18  (ST 23 ), and after the back end of the bill is detected by the discharge detecting sensor  18 , the bill conveyor motor  13  is driven to rotate normally by the predetermined amount (ST 24  and ST 25 ). 
     The process for driving the bill conveyor motor  13  to rotate normally in ST 24  and ST 25  corresponds to a driving amount for which the bill is conveyed in the receiving port  103  of the bill housing part  100  from the discharge slot  3   a  on the downstream side of the bill traveling route  3  of the apparatus main body  2  so that the pair of belts  150  contact the surface on both sides of the conveyed-in bill to guide the bill stably to the press standby part  108 . That is, by further driving the bill conveyor motor  13  to rotate normally for a predetermined amount after the trailing end of the bill is detected by the discharge detecting sensor  18 , the pair of belts  150  contact the bill conveyed-in and are driven in the bill feeding direction so as to guide the bill in a stable state to the press standby part  108 . 
     Then, after the above-described bill conveyor motor  13  is stopped, the process for driving the presser plate  115  is executed (ST 26 ) such that the bill is placed on the placing plate  105 . And, after the pressing process is completed, the presser plate  115  is again moved to the standby position and stopped to the position. 
     Also, in the process of ST 21  as described above, when the inserted bill is judged as a non-legitimate bill (ST 21 ; No), a traveling route opening process is executed (ST 51 , refer to ST 100  to ST 102  of  FIG. 10 ), then, the bill conveyor motor  13  is driven to rotate reversely, and the conveyor roller pair ( 14 A and  14 B) are brought into contact with each other such that the bill waiting at the escrow position is conveyed toward the bill insertion slot  5  (ST 52  and ST 53 ). Then, when the insertion detecting sensor  7  detects the trailing end of the bill to be returned toward the bill insertion slot  5 , the driving to reversely rotate the bill conveyor motor  13  is stopped, and above-described roller up-and-down motor  70  is driven to make the conveyor roller pair ( 14 A and  14 B) in a state of nipping and holding the bill therebetween separate from each other (ST 54  to ST 56 ). After that, the traveling route closing process is executed (refer to ST 57 , and ST 130  to ST 132  in  FIG. 12 ) and the driving motor  20  for the presser plate  115  is driven to rotate normally (ST 58 ) such that the presser plate  115  positioned at the initial position is driven to move to the standby position, and then a series of processes are completed. 
     In the bill processing apparatus having the above configuration, when a bill that is legitimate but has some state change in a predetermined area is inserted, first, the determining part determines whether there is some state change (being wet or defective, such as being pierced) and, when there is some state change, excludes the predetermined area from the authenticity judgment. In this way, it is less likely that a legitimate bill will be judged to be a forged bill because of its state change and the accuracy of authenticity judgment can be improved. 
     Particularly, in this embodiment, a predetermined area of a bill is set up in areas other than the characteristic areas where irradiation with light of different wavelengths from the light emitting part constituting the bill reading means leads to different pixel information (the areas important for judging the authenticity of a bill). Even if the above state change has occurred in the predetermined area, it is less likely that the state change affects the authenticity judgment, preventing reduction in the accuracy of authenticity judgment. 
     Furthermore, in the above-described embodiment, the light receiving part is composed of a line sensor reading a bill across the entire width. Then, the above predetermined area and characteristic area s can precisely be identified, further improving the accuracy of authenticity judgment. 
     In an embodiment, the above predetermined area can be an area situated at a given position in the printed area excluding the watermarked parts and having a given size. In an image from the reflected light of a bill as shown in  FIG. 14 , the given position is at a distance L 1  from the left end and at a distance W 1  from the top end of the printed area. In other words, the given size is L 1 ×W 1 . This area can be treated as a monetary amount display area based on which the bill class is easily identified. Particularly, it is not always necessary to have characteristics such as light wavelength-dependent reflectance or transmittance. Conversely, there is no inconvenience in treating this area as a visually identifiable money class data area. Then, the reference data for authenticity judgment can be extracted based on the money class data. Similarly, the given position can be at a distance L 3  from the right end and at a distance W 3  from the bottom end of the printed area. Alternatively, the predetermined area can be at these two positions (multiple positions). In  FIG. 14 , it is seen that these areas are wet and the intensity of reflected light is lower. However, it is satisfactory that the money class,  100 , is identified from these areas. These areas can be excluded from the subsequent authenticity judgment process. 
     In regard to reading a bill as described above, more specific bill conditions will be described in another embodiment.  FIGS. 15 and 16  schematically show wet bills.  FIG. 15  schematically shows an image from the light transmitted through a bill M 1  and  FIG. 16  schematically shows an image from the light reflected by a bill M 2 . Here, both figures are top views of the bills seen from above (in the direction of the incident light). In other words, the transmitted light is viewed after it is reflected by a reflecting plate. In this way, the transmitted light image can be superimposed on the reflected light image for easier composition. 
     The bill has a watermarked part  202  or  212  nearly in the center (the above characteristic area) as an important part for authenticity judgment and a portrait  202  or  214  to the right thereof, which allows for intuitive authenticity judgment by so-called reflected light identification. However, the wet parts  206  and  208  allow light to easily transmit and appear as white in  FIG. 15 . On the other hand, the reflected light shows similarly wet parts  216  and  218  as blackish, subdued parts because diffuse reflection is reduced on their surfaces. For this reason, the transmitted light is brighter in such parts and the identification based on the brightness of images may not be conducted adequately. The watermarked parts  202  and  212  are not non-characteristic parts and, therefore, not excluded from the authenticity judgment. Furthermore, when it is determined that such wetting has caused state change, the discharging process can immediately be conducted before the subsequent detailed review process starts. Assuming that the areas of the portraits  204  and  214  are non-characteristic area s, it is preferable that these parts are excluded from the authenticity judgment. 
     In discussion on the principle, presumably, the incident light energy Ei yields reflected light energy Er upon reflection on the surface of a bill, transmitted light energy Et upon transmission through the bill, or optically absorbed energy Ea absorbed by the bill. In other words, an equation Ei=Er+Et+Ea is generally satisfied. Here, Ea is increased as the pixels are darker in color (closer to 255). The value of a pixel is presented by V (0 to 255). On the other hand, the optically absorbed energy Ea presumably does not greatly change by wetting; then, Ea=αEi (0&lt;α=k·V&lt;1). Next, the reflected light energy Er is generally larger than the transmitted light energy Et; then, presumably Et=βEr (0&lt;β&lt;1) in general. However, this relationship is inverted where it is wet; then, presumably Et=γEr (0&lt;γ&lt;1). Hence, Ei=αEi+βEr+Er. Then, Er=(1−α)/(1+β)×Ei. Furthermore, Et=βEr. Ei is presumably constant. The reflected light energy Er is determined by the absorptance and the ratio of transmission/reflection. On the other hand, in the wet parts, Er=(1−α)/(1+1/γ)×Ei and then Et=1/γ×Er. 
     Here, assuming that k=2.7×10 −3 , β=0.50, and γ=0.67, Er=(1−2.7×10 −3 ×V)/(1+0.5)×Ei. Then, Et=βEr=β×(1−2.7×10 −3 ×V)/(1+0.5)×Ei. On the other hand, in the wet parts, Er=(1−2.7×10 −3 ×V)/(1+1.5)×Ei. Then, Et=1/γ×Er=(1−2.7×10 3 ×V)/(1+1.5)/0.67×Ei. This matter is shown in the table of  FIG. 17  in more specific numbers. The pixel position (x, y) is given by the column and row numbers. In the figure, a wet part  226  where the reflection and transmission trade places is enclosed by solid lines. As seen from the figure, the subtraction of transmitted light from reflected light yields a negative value and the transmitted light is more intense in the wet part  226 . Such an area can be a predetermined area. Alternatively, a preset area including such an area can be a predetermined area (x=1 to 4, y=3 to 10). When the number of pixels in the area  226  (x=2 to 3, y=4 to 8) where the inversion has occurred has reached a given rate or higher (for example, 10/32 or higher), it can be assumed that the predetermined area has some state change. For example, in the above-described embodiment, some state change is assumed when the equation (1) is satisfied. Here, the number of pixels constituting a predetermined area (for example more than half the number) is used as a criterion. Furthermore, although a predetermined area can be a preset area such as empirically particularly often wet parts, a predetermined area can also be set up by determining the number of pixels constituting a predetermined area (continuous area) in advance with or without determining a shape such as a square in advance, and shifting the area where the above criterion is satisfied (more than half the number of pixels, satisfying the equation 1) little by little. 
     In the paper sheet processing apparatus having the above configuration, the determining part can determine whether the paper sheet has some state change (mainly being wet or defected such as pierced) based on the brightness of the pixels of the transmitted image of a predetermined area of the paper sheet and the brightness of the pixels of the reflected image corresponding to the predetermined area of the reflected image. When the paper sheet has some state change in the predetermined area, the predetermined area is excluded from the authenticity judgment and the possibility of a legitimate bill being judged to be a forged bill is reduced, improving the accuracy of authenticity judgment. 
     Furthermore, in the invention relating to the above embodiment, the predetermined area is characteristically set up in areas other than the characteristic areas where irradiation with light of different wavelengths from the light emitting part leads to different pixel information. 
     In the paper sheet processing apparatus having the above configuration, since the area where irradiation with light of different wavelengths from a light emitting part leads to different pixel information is an area presenting characteristics (characteristic area) in judging the authenticity of a paper sheet, the predetermined area is set up in other areas so as to be excluded from the authenticity judgment. In other words, if there is some state change in an area that is not a characteristic area (a non-characteristic area), it is less likely that the authenticity judgment is particularly affected. Therefore, the predetermined area is set up in such a non-characteristic area to prevent reduction in the accuracy of authenticity judgment. In this regard, the characteristic area of a paper sheet corresponds for example to a watermarked image as formed on a bill. 
     Furthermore, the light receiving part can consist of a line sensor reading a paper sheet across the entire width. 
     The paper sheet processing apparatus having the above configuration can acquire image information of the paper sheet across the entire width by the line sensor and the predetermined area and characteristic area are precisely identified, further improving the accuracy of authenticity judgment. 
     Furthermore, a paper sheet processing apparatus that is a possible embodiment of the present invention can comprises a light emitting part emitting light to a paper sheet, a light receiving part receiving transmitted light and reflected light that are light emitted from the light emitting part and transmitted through/reflected by the paper sheet, a processor capable of controlling the light emitting part and light receiving part, and a storage part connected to the processor. Here, the processor can numerically express the transmitted light and reflected light received by the light receiving part based on their brightness on the basis of pixels containing color information including brightness and having a given unit size, and store them in the storage part in association with the position of the pixel on the bill. Furthermore, it can compare the reflected light and transmitted light at each pixel position and, when they have a given relationship, store in the storage part the position in association with a marker for not using the pixel data at that position in the authentication process. Then, among the pixel data stored in the storage part, the pixel data at the position associated with the marker are excluded in judging the authenticity of paper sheets. The marker can be, for example, a so-called flag or additional attribute data. Preferably, the position and brightness of a pixel can be extracted using the marker. 
     Furthermore, the processor may be allowed to judge the authenticity of paper sheets using only the pixel data for a given position of the bill among the pixel data. The pixel data for a given position may be, for example, data relating a part capable of providing different information depending on the wavelength of irradiation light such as a watermarked part. The part at a given position is not a part at a position associated with a marker as described above. 
     Then, the processor can divide the bill into small divisions and, when the number of pixels corresponding to a position associated with a marker in a small division has reached a given rate, exclude all pixel data for that small division from the authentication process. The small division can be an area consisting of a given number of pixels. For example, it can be a money class display area. However, the small area does not belong to a so-called characteristic area. 
     An authenticity judgment method for judging the authenticity of a paper sheet by irradiating the paper sheet with light and analyzing images from the reflected light and transmitted light can be provided, wherein the method comprises the following steps: irradiating the paper sheet with light; acquiring the reflected light along with the positional information of the paper sheet; acquiring the transmitted light along with the positional information of the paper sheet; determining the presence/absence of some state change in a predetermined area based on the reflected light and transmitted light data of the predetermined area at a predetermined position; and excluding the predetermined area from the area for authenticity judgment when the presence of some state change is assumed. The presence of some state change can be assumed when the difference in brightness between the reflected light and transmitted light is equal to or larger than a threshold as a result of comparison with reference data stored in advance. 
     The predetermined area belongs to a non-characteristic area. Furthermore, a step of determining the money class based on the reflected light or transmitted light data of the predetermined area can be included. 
     As mentioned above, the embodiment of the present invention is described. However, the present invention is not limited to the above-described embodiments, and various modifications of the present invention can be implemented. 
     For example, the predetermined area that is excluded from the authenticity judgment when it has some state change can be set up at multiple positions on a bill and its area can be changed as appropriate. In addition, the present invention is characterized in that the authenticity judgment process is executed, when a state change occurs in a predetermined area, by excluding the predetermined area, and the other configuration is not limited to the above-described embodiments, but various modifications may be made to. For example, a configuration, arrangement, etc. of the of the bill reading mean  8  may be appropriately modified. 
     The present invention can provide a paper sheet processing apparatus capable of improving the accuracy of authenticity judgment even if the paper sheet is wet and has some state change. 
     The present invention can be applied not only to the bill processing apparatus, but also to a device which provides various kinds of products and services when the paper sheet such as a service ticket and a coupon ticket, for example, is inserted.