Abstract:
Provided is a card insertion unit for a card reader which, without weakening a magnetic field generated by a magnetic field generating device in order to prevent reading of magnetic data by a magnetic head for skimming, is capable of reducing the effect of the magnetic field upon the reading of the magnetic data by way of the magnetic head for data reading. This card insertion unit ( 4 ) is provided with a notch ( 4   c ) formed at a point at which a magnetic stripe ( 2   a ) passes at insertion time of the card ( 2 ), a projecting portion ( 4   b ) which projects toward the upstream side of the insertion direction of the card ( 2 ), and a magnetic field generating device ( 14 ) disposed in the interior of the projecting portion ( 4   b ). The magnetic field generating device ( 14 ) is provided with a core ( 15 ) and a coil ( 16 ), and is disposed so that magnetic lines of force representing the magnetic field generated by the magnetic field generating device ( 14 ) pass through the position passed through by the magnetic stripe ( 2   a ) at insertion time of the card ( 2 ), and the direction in which the magnetic lines of force leave the end surfaces of the core ( 15 ) and the direction in which the magnetic lines of force enter the end surfaces of the core ( 15 ) are tilted with respect to the insertion direction of the card ( 2 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a card insertion part for a card reader into which a card having a magnetic stripe is inserted, and a card reader provided with the card insertion part. 
       BACKGROUND ART 
       [0002]    Conventionally, a card reader structured to read magnetic data on a card and/or record magnetic data on a card has been widely utilized. In an industry of the financial institutions where the card reader is utilized, a so-called skimming has conventionally become a serious problem in which a criminal attaches a magnetic head to a card insertion part of the card reader to illegally acquire magnetic data of a card by using the magnetic head. In order to prevent this problem, a card reader has been proposed which is provided with a disturbing magnetic field generator for preventing reading of magnetic data by using a magnetic head for skimming (hereinafter, referred to as a “skimming magnetic head” (see, for example, Patent Literature 1). 
         [0003]    In the card reader described in Patent Literature 1, at the time of card insertion when a card is to be inserted into the card reader, a disturbing magnetic field generator is driven for a predetermined time period to generate a disturbance magnetic field. Therefore, even when a skimming magnetic head is attached to a card insertion part, it is possible that illegal acquisition of magnetic data is prevented by preventing appropriate reading of magnetic data through the skimming magnetic head. 
       CITATION LIST 
     Patent Literature 
       [0004]    [PTL 1] Japanese Patent No. 3936496 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0005]    The card reader described in Patent Literature 1 is provided with a disturbance magnetic field generator and thus, as described above, reading of magnetic data by a skimming magnetic head can be prevented. However, in the card reader, the magnetic field generated by the disturbing magnetic field generator may affect reading of magnetic data by a magnetic head for data reading which is arranged in an inside of the card reader. In order to reduce the problem, it is conceivable that the disturbing magnetic field generated by the disturbing magnetic field generator is reduced, or that generation of the disturbing magnetic field is stopped at the time of reading of magnetic data by the magnetic head for data reading. However, according to these measures, it may be difficult to prevent reading of magnetic data by a skimming magnetic head. 
         [0006]    In view of the problem described above, an objective of the present invention is to provide a card insertion part for a card reader which is capable of reducing influence of a magnetic field generated by a magnetic field generation device on reading of magnetic data by a magnetic head for reading of magnetic data disposed in an inside of the card reader without reducing the magnetic field generated by the magnetic field generation device for preventing reading of magnetic data by a skimming magnetic head or without stopping generation of the magnetic field at the time of reading of magnetic data by the magnetic head for reading of magnetic data for preventing reading of magnetic data by a skimming magnetic head. Further, another objective of the present invention is to provide a card reader provided with the card insertion part. 
       Solution to Problem 
       [0007]    To achieve the above objective, the present invention provides a card insertion part for a card reader into which a card having a magnetic stripe is to be inserted, including a cut-off part which is formed at least at a portion where the magnetic stripe passes when the card is inserted, a protruded part which is adjacent to the cut-off part in a widthwise direction of the card which is substantially perpendicular to an inserting direction of the card and is protruded toward an upstream side in the inserting direction of the card, and a magnetic field generation device which is disposed in an inside of the protruded part and is structured to generate a magnetic field. The magnetic field generation device includes a core formed of magnetic material and a coil wound around the core, and the magnetic field generation device is disposed so that magnetic lines of force indicating the magnetic field generated by the magnetic field generation device are passed through a position where the magnetic stripe is passed when the card is inserted and so that a direction of the magnetic lines of force coming out from an end face of the core and/or a direction of the magnetic lines of force entering into an end face of the core are inclined with respect to the inserting direction of the card. 
         [0008]    In the card insertion part in accordance with the present invention, the magnetic field generation device is disposed so that, when a card is inserted, the magnetic lines of force generated by the magnetic field generation device pass the position where its magnetic stripe is passed. A skimming magnetic head is attached to a position where the magnetic stripe is passed and thus, according to the present invention, for example, reading of magnetic data by the skimming magnetic head is prevented by utilizing a magnetic field generated by the magnetic field generation device, or it can be detected that a skimming magnetic head has been attached to a front face side of the card insertion part. 
         [0009]    Further, in the present invention, the magnetic field generation device is disposed so that a direction of the magnetic lines of force coming out from an end face of the core and/or a direction of the magnetic lines of force entering into an end face of the core are inclined with respect to the inserting direction of the card. Therefore, the magnetic field generated by the magnetic field generation device does not easily affect on a magnetic head for reading data which is disposed in an inside of the card reader on a downstream side in the inserting direction of a card. Accordingly, influence of a magnetic field generated by the magnetic field generation device on reading of magnetic data by a magnetic head for reading of magnetic data is reduced without reducing the magnetic field generated by the magnetic field generation device or without stopping generation of the magnetic field at the time of reading of magnetic data by the magnetic head for reading data. 
         [0010]    Further, in the present invention, the cut-off part is formed at a portion where the magnetic stripe is passed when a card is inserted and thus, a criminal easily attaches a skimming magnetic head to the cut-off part. In other words, an attaching position of a skimming magnetic head is easily specified. Therefore, according to the present invention, a magnetic field for preventing reading of magnetic data by a skimming magnetic head is easily generated toward the skimming magnetic head, and it is easily detected that a skimming magnetic head is attached to the front face side of the card insertion part. 
         [0011]    Further, in the present invention, the magnetic field generation device is disposed in the inside of the protruded part which is required to form a cut-off part in which a part of a card is exposed so that a user is capable of holding the part of the card exposed in the cut-off part for taking out the card from the card insertion part. Therefore, the magnetic field generation device can be disposed in an inside of the protruded part which is usually formed as a dead space. Accordingly, in the present invention, a space for disposing the magnetic field generation device is not required to separately provide in the card insertion part and thus the size of the card insertion part can be reduced. 
         [0012]    In the present invention, the phrase of that “a direction of the magnetic lines of force coming out from an end face of the core and/or a direction of the magnetic lines of force entering into an end face of the core are inclined with respect to the inserting direction of the card” means that a direction of the magnetic lines of force coming out from an end face of the core and/or a direction of the magnetic lines of force entering into an end face of the core are not parallel to the inserting direction of the card, and that a direction of the magnetic lines of force coming out from an end face of the core and/or a direction of the magnetic lines of force entering into an end face of the core are inclined so as to cross the inserting direction of the card. This case may include that a direction of the magnetic lines of force coming out from an end face of the core and/or a direction of the magnetic lines of force entering into an end face of the core are substantially parallel to the widthwise direction of the card. 
         [0013]    In the present invention, it is preferable that the magnetic field generation device is disposed so that, when viewed in a thickness direction of the card which is substantially perpendicular to the inserting direction of the card and the widthwise direction of the card, the direction of the magnetic lines of force coming out from an end face of the core and/or the direction of the magnetic lines of force entering into an end face of the core are substantially parallel to the widthwise direction of the card. In other words, in the present invention, for example, it is preferable that the core is disposed with the widthwise direction of the card as a direction of a center axis of the core when viewed in a thickness direction of the card which is substantially perpendicular to the inserting direction of the card and the widthwise direction of the card, and the coil is wound around with the center axis of the core as a center. According to this structure, even when a distance between a magnetic head for reading data and the magnetic field generation device is small in the inserting direction of the card, influence of the magnetic field generated by the magnetic field generation device is hard to be applied to the magnetic head for reading data. Therefore, while influence of the magnetic field generated by the magnetic field generation device on reading of magnetic data by the magnetic head for reading data is reduced, a distance between the magnetic head for reading data and the magnetic field generation device can be shortened in the inserting direction of a card and, as a result, the size of the card reader to which the card insertion port is attached can be reduced. 
         [0014]    In the present invention, for example, the magnetic field generation device is structured to generate a disturbing magnetic field for disturbing reading of magnetic data recorded in the magnetic stripe by a skimming magnetic head which is attached to a front face side of the card insertion part. In this case, reading of magnetic data by a skimming magnetic head is prevented by a disturbing magnetic field which is generated by the magnetic field generation device. 
         [0015]    In the present invention, it is preferable that a part of the magnetic field generation device is disposed on a downstream side in the inserting direction of the card with respect to a downstream side end face of the cut-off part in the inserting direction of the card. Further, in the present invention, it is preferable that the center axis of the core is disposed in the inserting direction of the card at the same position as a downstream side end face of the cut-off part in the inserting direction of the card, or the center axis of the core is disposed on a downstream side with respect to the downstream side end face of the cut-off part. In a case that the position of the center axis of the core is coincided with the center position of a skimming magnetic head in the inserting direction of a card, even when a disturbing magnetic field is generated by the magnetic field generation device, the disturbing magnetic field does not act on the skimming magnetic head as a disturbing magnetic field. In other words, in a case that the position of the center axis of the core and the center position of a skimming magnetic head are coincided with each other in the inserting direction of a card, even when a disturbing magnetic field is generated by the magnetic field generation device, noise for disturbing reading of data is not added to magnetic data read by the skimming magnetic head. 
         [0016]    In a case that a part of the magnetic field generation device is disposed on a downstream side with respect to the downstream side end face of the cut-off part in the inserting direction of a card, the center position of a skimming magnetic head and the position of the center axis of the core are easily prevented from being coincided with each other in the inserting direction of a card. Therefore, in this case, reading of magnetic data by a skimming magnetic head is prevented by a disturbing magnetic field generated by the magnetic field generation device with a higher degree of probability. Further, when the center axis of the core is disposed in the inserting direction of a card at the same position as the downstream side end face of the cut-off part in the inserting direction of the card, or on a downstream side with respect to the downstream side end face of the cut-off part, the center position of the skimming magnetic head and the position of the center axis of the core are prevented from being coincided with each other in the inserting direction of a card. Therefore, in this case, reading of magnetic data by a skimming magnetic head is surely prevented by a disturbing magnetic field generated by the magnetic field generation device. 
         [0017]    In the present invention, it is preferable that the magnetic field generation device includes a cable structured to supply an electric current to the coil, and the cable is disposed and routed in a vicinity of the downstream end face of the cut-off part. According to this structure, for example, when a criminal cuts and removes a downstream end face of the cut-off part toward a downstream side for setting the position of the center axis of the core and the center position of a skimming magnetic head to coincide with each other in the inserting direction of a card, the cable may be disconnected. Therefore, for example, when disconnection of the cable is detected, it may be detected that a criminal has performed a trick for setting the position of the center axis of the core and the position of the center position of the skimming magnetic head to coincide with each other in the inserting direction of a card. 
         [0018]    The card insertion part in accordance with the present invention may be used in a card reader having a magnetic head structured to read magnetic data recorded in a magnetic stripe. In the card reader, influence of a magnetic field generated by the magnetic field generation device on reading of magnetic data by a magnetic head for reading magnetic data is reduced without reducing a magnetic field generated by the magnetic field generation device, or without stopping generation of the magnetic field when magnetic data are to be read by the magnetic head for reading data. 
       Advantageous Effects of Invention 
       [0019]    As described above, according to the card insertion part and the card reader in accordance with the present invention, influence of a magnetic field generated by the magnetic field generation device on reading of magnetic data by a magnetic head for reading of magnetic data is reduced without reducing a magnetic field generated by the magnetic field generation device or without stopping generation of the magnetic field at the time of reading of magnetic data by the magnetic head for reading data. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0020]      FIG. 1  is a perspective view showing a card reader in accordance with an embodiment of the present invention. 
           [0021]      FIG. 2  is a schematic cross-sectional view showing a front face side of the card reader in  FIG. 1 . 
           [0022]      FIG. 3  is an explanatory schematic plan view showing a structure of the front face side of the card reader shown in  FIG. 1 . 
           [0023]      FIG. 4  is an explanatory view showing a structure of a magnetic field generation device shown in  FIG. 3 . 
           [0024]      FIGS. 5(A) through 5(D)  are views for explaining advantageous effects of the card reader shown in  FIG. 1 . 
           [0025]      FIG. 6  is an explanatory view showing a structure of a magnetic field generation device in accordance with another embodiment of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0026]    Embodiments of the present invention will be described below with reference to the accompanying drawings. 
       (Schematic Structure of Card Reader) 
       [0027]      FIG. 1  is a perspective view showing a card reader  1  in accordance with an embodiment of the present invention.  FIG. 2  is a schematic cross-sectional view showing a front face side of the card reader  1  in  FIG. 1 . 
         [0028]    A card reader  1  in this embodiment is a device which is structured to perform reading of magnetic data recorded on a card  2  and/or recording of magnetic data on a card  2 , and is, for example, mounted and used in a predetermined host apparatus such as an ATM. The card reader  1  is, as shown in  FIGS. 1 and 2 , provided with a card insertion part  4  formed with an insertion port  3  into which a card  2  is inserted, and a main body part  6  in which a card feeding passage  5  for feeding the card  2  is formed. An inside of the main body part  6  is disposed with a magnetic head  7  for performing reading of magnetic data and/or recording of magnetic data, and a drive roller  8  and a pad roller  9  for feeding the card  2 . 
         [0029]    In this embodiment, a card  2  is fed in an “X” direction shown in  FIG. 1  and the like. Specifically, a card  2  is inserted in an “X1” direction and the card  2  is ejected in an “X2” direction. In other words, the “X1” direction is an inserting direction of a card  2  and the “X2” direction is an ejecting direction of a card  2 . Further, the “X1” direction side is a downstream side in the inserting direction of a card  2  and the “X2” direction side is an upstream side in the inserting direction of a card  2 . In addition, a “Z” direction in  FIG. 1  and the like which is substantially perpendicular to the “X” direction is a thickness direction of a card  2 , and a “Y” direction in  FIG. 1  and the like which is substantially perpendicular to the “X” direction and the “Z” direction is a widthwise direction (short widthwise direction) of a card  2 . In the following descriptions, the “X1” direction side is referred to as a “back” (rear) side, the “X2” direction side is referred to as a “front” side, a “Y1” direction side is a “right” side, a “Y2” direction side is a “left” side, a “Z1” direction side is an “upper” side, and a “Z2” direction side is a “lower” side. 
         [0030]    A card  2  is, for example, a rectangular card made of vinyl chloride whose thickness is about 0.7-0.8 mm. A magnetic stripe  2   a  (see  FIG. 3 ) in which magnetic data are recorded is formed on a rear face (under face) of the card  2 . In accordance with an embodiment of the present invention, an IC chip may be fixed on a surface of a card  2  and an antenna for communication may be incorporated in a card  2 . Further, the card  2  may be a PET (polyethylene terephthalate) card whose thickness is about 0.18-0.36 mm or may be a paper card having a predetermined thickness. 
         [0031]    The card insertion part  4  is attached to a front end face of the main body part  6 . A detailed structure of the card insertion part  4  will be described below. 
         [0032]    A magnetic head  7  is disposed so that its gap part faces the card feeding passage  5  from a lower side. Further, the magnetic head  7  is disposed at a position so as to be capable of contacting with a magnetic stripe  2   a  of a card  2 . An opposite roller  10  is disposed on an upper side of the magnetic head  7  and faces the magnetic head  7  in an upper and lower direction. The drive roller  8  is disposed so as to face the card feeding passage  5  from a lower side. A pad roller  9  faces the drive roller  8  on an upper side with respect to the drive roller  8  and is urged toward the drive roller  8 . 
       (Structure of Card Insertion Part) 
       [0033]      FIG. 3  is an explanatory schematic plan view showing a structure of the front face side of the card reader  1  shown in  FIG. 1 .  FIG. 4  is an explanatory view showing a structure of a magnetic field generation device  14  shown in  FIG. 3 . 
         [0034]    The card insertion part  4  is provided with a fixed part  4   a  which is fixed to the main body part  6  and a protruded part  4   b  which protrudes toward a front side from the fixed part  4   a . The protruded part  4   b  is not formed over the entire area in the right and left direction of the card insertion part  4 . Specifically, the protruded part  4   b  is formed in a predetermined area from a left end of the card insertion part  4  toward its right end side and the right side of the protruded part  4   b  is formed as a cut-off part  4   c  where a portion protruding from the fixed part  4   a  toward the front side is not existed. In other words, the protruded part  4   b  and the cut-off part  4   c  are adjacent to each other in the right and left direction. 
         [0035]    The protruded part  4   b  is formed in a hollow shape. Further, the protruded part  4   b  is provided with an upper side protruded part  4   d  and a lower side protruded part  4   e  which are disposed so as to interpose the insertion port  3  therebetween in the upper and lower direction. A magnetic field generation device  14  structured to generate a magnetic field is disposed in an inside of the lower side protruded part  4   e  which is disposed on a lower side with respect to the insertion port  3 . The cut-off part  4   c  is, as shown in  FIG. 3 , formed at a position where the magnetic head  7  is disposed in the right and left direction. In other words, the cut-off part  4   c  is formed at a portion where a magnetic stripe  2   a  of a card  2  is passed. In this embodiment, the protruded part  4   b  is disposed with a card detector (not shown) for detecting that a card  2  is inserted into the insertion port  3 . 
         [0036]    The magnetic field generation device  14  is provided with a core  15  formed of magnetic material and a coil  16  for excitation which is wound with a center axis “CL” of the core  15  as a center. The core  15  is formed in a substantially rectangular solid bar shape. The coil  16  is wound around at a center position of the core  15 . Each of both end parts of the coil  16  is connected with a terminal not shown. One of the terminals is connected with a power supply not shown through a predetermined cable and the other of the terminals is grounded through a predetermined cable. In this embodiment, the cable connected with the terminal with which the end part of the coil  16  is connected is disposed and routed in an inside of the fixed part  4   a  on a back side of a back end face  4   f  of the cut-off part  4   c . The back end face  4   f  in this embodiment is a downstream side end face of the cut-off part  4   c  in an inserting direction of a card  2 . 
         [0037]    As shown in  FIG. 3 , the core  15  is disposed with the right and left direction as an axial direction of its center axis “CL”. In other words, the core  15  is disposed in an inside of the protruded part  4   b  so that its center axis “CL” is parallel to the right and left direction. A part of the core  15  is disposed on a back side with respect to the back end face  4   f  of the cut-off part  4   c  in the front and rear direction. Further, the center axis “CL” of the core  15  is disposed on a back side with respect to the back end face  4   f  of the cut-off part  4   c  in the front and rear direction. Specifically, the center axis “CL” of the core  15  is disposed on a slightly back side with respect to the back end face  4   f  of the cut-off part  4   c  in the front and rear direction. 
         [0038]    The magnetic field generation device  14  in this embodiment functions as a disturbing magnetic field generation device structured to generate a disturbing magnetic field for disturbing reading of magnetic data of a card  2  by a skimming magnetic head  20  which is attached to the front face side of the card insertion part  4 . Therefore, the magnetic field generation device  14  is disposed so that magnetic lines of force “ML” (see  FIG. 4 ) representing a magnetic field generated from the magnetic field generation device  14  are passed through at an attaching position of the skimming magnetic head  20 . In other words, the magnetic field generation device  14  is disposed so that the magnetic lines of force “ML” pass through the position where the magnetic stripe  2   a  of a card  2  is passed at the time of insertion of the card  2 . It is considered that a skimming magnetic head  20  is attached to the cut-off part  4   c  where a skimming magnetic head  20  is easily attached and thus, in this embodiment, the magnetic field generation device  14  is disposed so that the magnetic lines of force “ML” pass the cut-off part  4   c . In  FIG. 4 , one magnetic line of force “ML” is shown for convenience but actually, the magnetic field generated by the magnetic field generation device  14  is formed of a large number of magnetic lines of force “ML”. 
         [0039]    In the magnetic field generation device  14 , the coil  16  is excited to generate a magnetic field for disturbance. As shown in  FIG. 4 , in the magnetic lines of force “ML” representing the magnetic field generated by the magnetic field generation device  14 , its direction entering into the center of one end face (end face in the center axis “CL” direction) of the core  15  and its direction coming out from the center of the other end face of the core  15  are substantially coincided with the axial direction of the center axis “CL” of the core  15 . In other words, in this embodiment, the direction of the magnetic lines of force “ML” entering into the center of one end face of the core  15  and the direction of the magnetic lines of force “ML” coming out from the center of the other end face of the core  15  are substantially parallel to the right and left direction. 
       (Schematic Operation of Card Reader) 
       [0040]    In the card reader  1  structured as described above, the card feeding passage  5  is closed by a shutter member not shown in a standby state when a card  2  is not inserted and a card  2  is unable to be inserted into the card reader. In this state, when a card detector disposed at the card insertion part  4  detects that a card  2  is inserted into the insertion port  3 , the card feeding passage  5  is opened and the card  2  is taken into the inside of the card reader  1 . Further, when the card detector detects that a card  2  is inserted, the magnetic field generation device  14  generates a magnetic field for disturbance. For example, the magnetic field generation device  14  generates a magnetic field for disturbance until a card  2  inserted from the insertion port  3  and taken into the inside of the card leader  1  is ejected. Alternatively, the magnetic field generation device  14  generates a magnetic field for disturbance during that feeding of a card  2  is performed from a time that the card  2  is inserted from the insertion port  3  and taken into the inside of the card leader  1  and until the card is ejected. 
         [0041]    A front end of the card  2  ejected by the drive roller  8  and the pad roller  9  is located on a front side with respect to the back end face  4   f  of the cut-off part  4   c  but is located on a back side with respect to the front end face of the protruded part  4   b . In other words, the front end side of the card  2  ejected by the drive roller  8  and the pad roller  9  is exposed in the cut-off part  4   c . When the card  2  is ejected from the card reader  1 , a user holds the front end side of the card  2  exposed in the cut-off part  4   c  and takes out the card  2  from the card reader  1 . The protruded part  4   b  is provided for forming the cut-off part  4   c  where a card  2  is capable of being held when the card  2  is to be taken out from the card reader  1 . 
         [0000]    (Principal Effects in this Embodiment) 
         [0042]    As described above, in this embodiment, the magnetic field generation device  14  is disposed so that its magnetic lines of force “ML” pass a position where a magnetic stripe  2   a  of a card  2  is passed at the time of insertion of the card  2  (in other words, the position where it is considered that a skimming magnetic head  20  is attached). Therefore, even when a skimming magnetic head  20  is attached to the front face side of the card insertion part  4 , reading of magnetic data by a skimming magnetic head  20  is prevented by magnetic field for disturbance generated by the magnetic field generation device  14 . 
         [0043]    Further, in this embodiment, the core  15  is disposed so that its center axis “CL” is parallel to the right and left direction, and the direction of the magnetic lines of force “ML” entering into the center of one end face of the core  15  and the direction of the magnetic lines of force “ML” coming out from the center of the other end face of the core  15  are parallel to the right and left direction. Therefore, the magnetic field for disturbance generated by the magnetic field generation device  14  is hard to affect the magnetic head  7  which is disposed on the back side with respect to the magnetic field generation device  14 . Accordingly, in this embodiment, without reducing the magnetic field generated by the magnetic field generation device  14  or, without stopping generation of the magnetic field at the time of reading of magnetic data by the magnetic head  7 , influence of the magnetic field generated by the magnetic field generation device  14  on reading of magnetic data by the magnetic head  7  is reduced. 
         [0044]    Especially, in this embodiment, the center axis “CL” of the core  15  is parallel to the right and left direction. Therefore, even when a distance between the magnetic head  7  and the magnetic field generation device  14  is short in the front and rear direction, influence of the magnetic field for disturbance generated by the magnetic field generation device  14  is hard to affect the magnetic head  7 . Accordingly, in this embodiment, while influence of the magnetic field generated by the magnetic field generation device  14  which affects reading of magnetic data by the magnetic head  7  is reduced, a distance between the magnetic head  7  and the magnetic field generation device  14  can be shortened in the front and rear direction and, as a result, the size of the card reader  1  can be reduced. 
         [0045]    In this embodiment, the cut-off part  4   c  is formed at a portion where the magnetic stripe  2   a  passes at the time of insertion of a card  2 . Therefore, a criminal may easily attach a skimming magnetic head  20  to the cut-off part  4   c . Accordingly, in this embodiment, an attaching position of a skimming magnetic head  20  is easily determined and, as a result, a magnetic field for preventing reading of magnetic data by a skimming magnetic head  20  is easily generated toward the skimming magnetic head  20 . Further, in this embodiment, the front end side of a card  2  ejected by the drive roller  8  and the pad roller  9  is exposed in the cut-off part  4   c  and a user holds the front end side of the card  2  exposed in the cut-off part  4   c  and takes out the card  2  from the card reader  1 . Therefore, the user easily notices that a skimming magnetic head  20  is attached to the cut-off part  4   c.    
         [0046]    In this embodiment, the magnetic field generation device  14  is disposed in the inside of the protruded part  4   b  which is required to form the cut-off part  4   c  for holding the front end side of a card  2  exposed in the cut-off part  4   c  and for taking out the card  2  from the card reader  1 . Therefore, the magnetic field generation device  14  can be disposed by utilizing an inside of the hollow-shaped protruded part  4   b  which is usually formed as a dead space. Accordingly, in this embodiment, a space for disposing the magnetic field generation device  14  is not required to be provided separately in the card insertion part  4  and thus, the size of the card insertion part  4  is reduced. 
         [0047]    In this embodiment, as shown in  FIGS. 5(C) and 5(D) , in a case that the position of the center axis “CL” of the core  15  and the position of the center “CL1” of a skimming magnetic head  20  are coincided with each other in the front and rear direction, even though a magnetic field for disturbance is generated by the magnetic field generation device  14 , the magnetic field does not act on the skimming magnetic head  20  as a magnetic field for disturbance. In other words, in a case that the skimming magnetic head  20  is provided with a core  21  and a coil  22  wound around the core  21 , and the core  21  is provided with a first core part  21   a  and a second core part  21   b  facing each other in the front and rear direction through a magnetic gap  20   a , when the position of the center axis “CL” of the core  15  and the center “CL1” of the skimming magnetic head  20  are coincided with each other in the front and rear direction, a direction of magnetic lines of force “ML1” indicating a magnetic field generated in the first core part  21   a  due to influence of the magnetic field generated by the magnetic field generation device  14  is opposite to a direction of magnetic lines of force “ML2” indicating a magnetic field generated in the second core part  21   b  due to influence of the magnetic field generated by the magnetic field generation device  14  and, in addition, the density of the magnetic lines of force “ML1” and the density of the magnetic lines of force “ML2” are equal to each other. Therefore, a magnetic field generated in the first core part  21   a  and a magnetic field generated in the second core part  21   b  are balanced with each other due to influence of the magnetic field generated by the magnetic field generation device  14  and thus an electric current due to influence of the magnetic field generated by the magnetic field generation device  14  does not flow the coil  22  and noise for disturbance is not applied to magnetic data which are read by the skimming magnetic head  20 . 
         [0048]    In this embodiment, the center axis “CL” of the core  15  is disposed on the back side with respect to the back end face  4   f  of the cut-off part  4   c  in the front and rear direction. Therefore, the position of the center “CL1” of the skimming magnetic head  20  which is attached to the front face side of the card insertion part  4  is not coincided with the position of the center axis “CL” of the core  15  in the front and rear direction. Accordingly, as shown in  FIGS. 5(A) and 5(B) , the density of the magnetic lines of force “ML1” indicating the magnetic field generated in the first core part  21   a  due to influence of the magnetic field generated by the magnetic field generation device  14  is different from the density of the magnetic lines of force “ML2” indicating the magnetic field generated in the second core part  21   b  due to influence of the magnetic field generated by the magnetic field generation device  14 . Therefore, due to the influence of the magnetic field generated by the magnetic field generation device  14 , the magnetic field generated in the first core part  21   a  and the magnetic field generated in the second core part  21   b  are not balanced with each other and thus, an electric current due to influence of the magnetic field generated by the magnetic field generation device  14  flows the coil  22  and noise for disturbance is applied to magnetic data which are read by the skimming magnetic head  20 . As a result, according to this embodiment, reading of magnetic data by the skimming magnetic head  20  is surely prevented by magnetic field for disturbance generated by the magnetic field generation device  14 . 
         [0049]    In this embodiment, a cable connected with terminals with which end parts of the coil  16  of the magnetic field generation device  14  are connected are disposed and routed in an inside of the fixed part  4   a  and the like on the back side of the back end face  4   f  of the cut-off part  4   c . Therefore, for example, when a criminal cuts and removes the back end face  4   f  toward the back side for setting the position of the center axis “CL” of the core  15  and the position of the center “CL1” of the skimming magnetic head  20  to coincide with each other in the front and rear direction, the cable may be disconnected. Accordingly, for example, when it is structured so that disconnection of the cable is detected, it may be detected that a criminal has performed a trick for setting the position of the center axis “CL” of the core  15  and the position of the center “CL1” of the skimming magnetic head  20  to coincide with each other in the front and rear direction. 
       (Modified Example of Magnetic Field Generation Device) 
       [0050]      FIG. 6  is an explanatory view showing a structure of a magnetic field generation device  34  in accordance with another embodiment of the present invention. 
         [0051]    Instead of using the magnetic field generation device  14  in the embodiment described above, a magnetic field generation device  34  shown in  FIG. 6  may be disposed in an inside of the lower side protruded part  4   e . The magnetic field generation device  34  is provided with a core  35  formed of magnetic material, a pair of coils  36  and  37  for excitation and a coil  38  for detection which are wound around with the center axis “CL” of the core  35  as a center, terminals (not shown) with which end parts of the coils  36  and  37  are connected, and terminals (not shown) with which end parts of the coil  38  are connected. 
         [0052]    The core  35  is formed in a thin plate shape whose thickness direction is a direction perpendicular to the paper surface in  FIG. 6 . The core  35  is structured of a center core part  35   a  which is disposed at a substantially center in an axial direction of the center axis “CL”, a pair of axial end core parts  35   b  which are disposed on respective both end sides of the center core part  35   a  in the axial direction of the center axis “CL”, and flange parts  35   c  which are disposed between the center core part  35   a  and the axial end core parts  35   b . A width of the center core part  35   a  is wider than a width of the axial end core part  35   b . Further, a width of the flange part  35   c  is wider than the width of the center core part  35   a.    
         [0053]    The coil  38  is wound around the center core part  35   a . Each of both end parts of the coil  38  is connected to the terminal. One end part of a predetermined cable is connected with the terminal and the other end part of the cable is connected with a control circuit board of the card reader  1 . 
         [0054]    The coils  36  and  37  are respectively wound around a pair of the axial end core parts  35   b . One end parts of the coils  36  and  37  are connected with terminals. The terminal is connected with one end part of a predetermined cable and the other end part of the cable is connected with an AC power source  40  through a variable resistor  39  which is mounted on the control circuit board of the card reader  1 . The other end parts of the coils  36  and  37  are connected with one end part of a conducting wire  41 . The other end part of the conducting wire  41  is connected with a terminal. The terminal is connected with one end part of a predetermined cable and the other end part of the cable is grounded. In this case, the cable connected with the terminals with which the end parts of the coils  36  and  37  for excitation are connected is disposed and routed in the inside of the fixed part  4   a  and the like on the back side with respect to the back end face  4   f  of the cut-off part  4   c.    
         [0055]    Similarly to the embodiment described above, the core  35  is disposed with the right and left direction as an axial direction of the center axis “CL”. Further, a part of the core  35  is disposed on the back side with respect to the back end face  4   f  of the cut-off part  4   c  in the front and rear direction. In addition, the center axis “CL” of the core  35  is disposed on the back side with respect to the back end face  4   f  of the cut-off part  4   c  in the front and rear direction. 
         [0056]    The magnetic field generation device  34  is provided with a function as a disturbing magnetic field generation device, which generates a disturbing magnetic field for disturbing reading of magnetic data of a card  2  by a skimming magnetic head  20  attached to the front face side of the card insertion part  4 , and a function as a magnetic sensor which is structured so that variation of a magnetic field generated by the coils  36  and  37  is detected by the coil  38  to detect attachment of the skimming magnetic head  20  to the front face side of the card insertion part  4 . Therefore, the magnetic field generation device  34  is disposed so that magnetic lines of force “ML11” indicating a magnetic field generated by the coil  36  or magnetic lines of force “ML12” indicating a magnetic field generated by the coil  37  pass an attaching position of the skimming magnetic head  20 . 
         [0057]    In a case that the magnetic field generation device  34  functions as a disturbing magnetic field generation device, the coils  36  and  37  are excited and a magnetic field for disturbance is generated. For example, a magnetic field for disturbance is generated so that magnetic lines of forces “ML11” and “ML12” are entered into the end faces of the axial end core parts  35   b . As shown in  FIG. 6 , the directions of the magnetic lines of forces “ML11” and “ML12” which enter into the centers of the end faces of the axial end core parts  35   b  are substantially coincided with the axial direction of the center axis “CL” of the core  35 . In accordance with an embodiment of the present invention, in the magnetic field generation device  34 , a magnetic field for disturbance may be generated so that magnetic lines of forces “ML11” and “ML12” come out from the end faces of the axial end core parts  35   b.    
         [0058]    Further, in a case that the magnetic field generation device  34  functions as a magnetic sensor, the coils  36  and  37  are excited so that, when no skimming magnetic head  20  is provided in a detectable area of the magnetic field generation device  34  (area where magnetic lines of force “ML11” or “ML12” passes), a density of the magnetic lines of force “ML11” indicating a magnetic field generated by the coil  36  and a density of the magnetic lines of force “ML12” indicating a magnetic field generated by the coil  37  are substantially equal to each other and, in addition, a direction of the magnetic lines of force “ML11” and a direction of the magnetic lines of force “ML12” are opposite to each other. In other words, when a skimming magnetic head  20  is not provided in a detectable area of the magnetic field generation device  34 , the variable resistor  39  is adjusted so that the magnetic field generated by the coil  36  and the magnetic field generated by the coil  37  are balanced with each other and thus, when a skimming magnetic head  20  is not provided in a detectable area of the magnetic field generation device  34 , a voltage is not generated between both end parts of the coil  38 . 
         [0059]    Therefore, when a skimming magnetic head  20  is attached in a detectable area of the magnetic field generation device  34 , a magnetic field generated by the coil  36  and a magnetic field generated by the coil  37  are not balanced with each other due to the influence of the skimming magnetic head  20  and thus a voltage is generated between both end parts of the coil  38 . As described above, the magnetic field generation device  34  detects the skimming magnetic head  20  by detecting a voltage generated between both end parts of the coil  38 . In a case that the magnetic field generation device  34  functions as a magnetic sensor, an exciting current supplied to the coils  36  and  37  is set to be smaller than an exciting current supplied to the coils  36  and  37  when the magnetic field generation device  34  functions as a disturbing magnetic field generation device. 
         [0060]    As described above, when the magnetic field generation device  34  is disposed instead of using the magnetic field generation device  14 , for example, the magnetic field generation device  34  functions as a magnetic sensor in a standby state when a card  2  is not inserted. Further, in a standby state, the card feeding passage  5  is closed by a shutter member and the like and thus a card  2  is unable to be inserted into the card reader  1 . In this state, when a metal member such as a skimming magnetic head  20  is detected by the magnetic field generation device  34 , the state that the card feeding passage  5  is closed is maintained and the state that a card  2  is unable to be inserted into the card reader  1  is maintained for preventing skimming. 
         [0061]    Further, in a standby state that a card  2  is not inserted and, in a state that the magnetic field generation device  34  does not detect a metal member such as a skimming magnetic head  20 , when a card detector disposed in the card insertion part  4  detect that a card  2  is inserted into the insertion port  3 , the magnetic field generation device  34  functions as a disturbing magnetic field generation device. In other words, when it is detected that a card  2  is inserted into the insertion port  3 , the magnetic field generation device  34  generates a magnetic field for disturbance. For example, the magnetic field generation device  34  generates a magnetic field for disturbance from the time when a card  2  is inserted into the insertion port  3  until the card  2  taken into the inside of the card reader  1  is ejected. 
         [0062]    As described above, when the magnetic field generation device  34  is disposed in the inside of the lower side protruded part  4   e  instead of the magnetic field generation device  14 , in a case that the magnetic field generation device  34  functions as a disturbing magnetic field generation device, reading of magnetic data by a skimming magnetic head  20  is prevented by a magnetic field for disturbance generated by the magnetic field generation device  34 , and alternatively, in a case that the magnetic field generation device  34  functions as a magnetic sensor, the magnetic field generation device  34  detects that a skimming magnetic head  20  is attached to the front face side of the card insertion part  4 . Further, without reducing the magnetic field generated by the magnetic field generation device  34 , or without stopping generation of the magnetic field at the time of reading of magnetic data by the magnetic head  7 , the effects similar to the embodiment described above can be obtained, for example, influence of the magnetic field generated by the magnetic field generation device  34  on reading of magnetic data by the magnetic head  7  is reduced. 
         [0063]    In accordance with an embodiment of the present invention, the magnetic field generation device  34  may have a function only as a magnetic sensor. Further, the magnetic field generation device  34  may generate a magnetic field for disturbance only when the magnetic field generation device  34  detects a metal member such a skimming magnetic head  20 . Further, the magnetic field generation device  34  may be structured of a core and a coil which is wound around the core and is used for both of excitation and detection. 
       Other Embodiments 
       [0064]    Although the present invention has been shown and described with reference to a specific embodiment, various changes and modifications will be apparent to those skilled in the art from the teachings herein. 
         [0065]    In the embodiment described above, the center axis “CL” of the core  15  is parallel to the right and left direction. However, the present invention is not limited to this embodiment. For example, in a case that the center axis “CL” of the core  15  is parallel to the right and left direction when viewed in the upper and lower direction, the center axis “CL” of the core  15  may be inclined with respect to the right and left direction when viewed in the front and rear direction. In this case, the magnetic field generation device  14  may be disposed in the inside of the lower side protruded part  4   e  or may be disposed in the inside of the upper side protruded part  4   d.    
         [0066]    Further, in the embodiment described above, the center axis “CL” of the core  15  is parallel to the right and left direction. However, under a condition that the center axis “CL” of the core  15  is not parallel to the front and rear direction (in other words, under a condition that the center axis “CL” is inclined with respect to the front and rear direction), the center axis “CL” of the core  15  may be inclined with respect to the right and left direction when viewed in the upper and lower direction. Also in this case, a magnetic field generated by the magnetic field generation device  14  is hard to affect the magnetic head  7 . Therefore, without reducing the magnetic field generated by the magnetic field generation device  14 , or without stopping generation of the magnetic field at the time of reading of magnetic data by the magnetic head  7 , influence of the magnetic field generated by the magnetic field generation device  14  on reading of magnetic data by the magnetic head  7  is reduced. 
         [0067]    In the embodiment described above, the center axis “CL” of the core  15  is disposed on the back side with respect to the back end face  4   f  of the cut-off part  4   c  in the front and rear direction. However, the present invention is not limited to this embodiment. For example, the center axis “CL” of the core  15  may be disposed at the same position as the back end face  4   f  of the cut-off part  4   c  in the front and rear direction. Further, the center axis “CL” of the core  15  may be disposed on the front side with respect to the back end face  4   f  of the cut-off part  4   c  when the center axis “CL” of the core  15  is disposed on the back side with respect to the center “CL1” of a skimming magnetic head  20 , or when the center axis “CL” of the core  15  is disposed on a front side with respect to the center “CL1” of a skimming magnetic head  20  (in other words, the position of the center axis “CL” of the core  15  and the position of the center “CL1” of a skimming magnetic head  20  are displaced from each other in the front and rear direction). Further, in the embodiment described above, a part of the core  15  is disposed on the back side with respect to the back end face  4   f  of the cut-off part  4   c  in the front and rear direction. However, the entire core  15  may be disposed on a front side with respect to the back end face  4   f  of the cut-off part  4   c  in the front and rear direction when the center axis “CL” of the core  15  is disposed on the back side with respect to the center “CL1” of a skimming magnetic head  20 , or when the center axis “CL” of the core  15  is disposed on the front side with respect to the center “CL1” of a skimming magnetic head  20 . 
         [0068]    In the embodiment described above, the protruded part  4   b  is formed over a predetermined area from a left end of the card insertion part  4  toward its right end side and the right side with respect to the protruded part  4   b  is formed as the cut-off part  4   c  where no protruding portion is formed from the fixed part  4   a  to the front side. However, the present invention is not limited to this embodiment. For example, the protruded part  4   b  may be structured of a first protruded part, which is formed over a predetermined area from the left end of the card insertion part  4  toward its right end side, and a second protruded part formed over a predetermined area from the right end of the card insertion part  4  toward its left end side, and a portion between the first protruded part and the second protruded part is formed as the cut-off part  4   c  where no protruding portion is formed from the fixed part  4   a  to the front side. As described above, it is sufficient that the cut-off part  4   c  is formed in the right and left direction at least at a portion where the magnetic head  7  is disposed. 
         [0069]    In the embodiment described above, the card reader  1  is a card feeding type card reader provided with the drive roller  8  and the pad roller  9 . However, a card reader to which the structure of the present invention is applied may be a manual type card reader in which reading and/or recording of magnetic data are performed while manually moving a card  2  by a user. For example, a card reader to which the structure of the present invention is applied may be a so-called dip type card reader in which reading and/or recording of magnetic data are performed when a card  2  is inserted into the card reader or when a card  2  is taken out from the card reader. 
       REFERENCE SIGNS LIST 
       [0000]    
       
         
           
               1  card reader 
               2  card 
               2   a  magnetic stripe 
               4  card insertion part 
               4   b  protruded part 
               4   c  cut-off part 
               4   f  back end face (downstream side end face) 
               7  magnetic head 
               14 ,  34  magnetic field generation device 
               15 ,  35  core 
               16 ,  36 ,  37  coil 
               20  skimming magnetic head 
             “CL” center axis 
             “ML” magnetic lines of force 
             “X1” inserting direction of card 
             “Y” widthwise direction of card 
             “Z” thickness direction of card