JP2017182852A - Magnetic head and card reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic head that can detect a change in magnetic field when a magnetic recording medium such as a magnetic card makes relative movements even in a jamming magnetic field.SOLUTION: A prehead 15 of a card reader 1 has: a first head main body 29 that includes a first core 32 equipped with a first gap 31 and a first coil 34 wound around the first core 32; a second head main body 30 that includes a second core 52 equipped with a second gap 51 and a second coil 54 wound around the second core 52; and a head case 21 that houses the first head main body 29 and the second head main body 30. The first head main body 29 and the second head main body 30 are arranged so that the first gap 31 and the second gap 51 are lined in a forward/rearward direction X (movement direction of a magnetic card 3). The prehead 15 is configured to output a differential signal serving as a difference between a first signal from the first coil 34 and a second signal from the second coil 54, in which in the differential signal, an influence of a jamming magnetic field 17 is cancelled.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a magnetic head that detects a change in a magnetic field when a magnetic recording medium such as a magnetic card passes. The present invention also relates to a card reader that detects whether or not a magnetic card has been inserted into a card insertion slot using a magnetic head.

  A card reader for reading magnetic information from a magnetic card having a magnetic track is described in Patent Document 1. The card reader of the literature includes a card insertion slot, a magnetic head, a card conveyance path extending from the card insertion slot via a reading position by the magnetic head, and a conveyance mechanism for conveying the magnetic card along the card conveyance path. . The card reader also includes a pre-head that magnetically detects that a magnetic card has been inserted into the card insertion slot. The detection position by the pre-head is set between the card insertion slot and the reading position.

  When it is detected that the magnetic card is inserted into the card insertion slot based on the output from the pre-head, the card reader drives the transport mechanism to transport the magnetic card along the card transport path. The card reader acquires magnetic information of the magnetic card based on the output from the magnetic head when the magnetic card passes through the reading position.

JP 2010-205187 A

  In recent years, there has been a problem of skimming in which a magnetic head is attached in the vicinity of a card insertion slot for illegal purposes and magnetic information is acquired from a magnetic card inserted into the card transport path from the card insertion slot.

  For skimming, a measure may be taken to generate a disturbing magnetic field in the vicinity of the card insertion slot and prevent reading of magnetic information by a magnetic head attached for illegal purposes. However, when a disturbing magnetic field is generated in the vicinity of the card insertion slot, the pre-head is affected by the disturbing magnetic field, which causes a problem that the insertion of the magnetic card into the card insertion slot cannot be accurately detected.

  In view of the above problems, an object of the present invention is to provide a magnetic head capable of detecting a change in a magnetic field when a magnetic recording medium such as a magnetic card relatively moves among disturbing magnetic fields. Another object is to provide a card reader using such a magnetic head as a pre-head.

  In order to solve the above problems, the present invention provides a magnetic head for detecting a change in a magnetic field when a magnetic recording medium relatively moves, and an even number of heads including a core having a gap and a coil wound around the core. A main body and a head case that houses the even number of head main bodies, and the even number of head main bodies are arranged such that the gaps of the head main bodies are aligned in the relative movement direction of the magnetic recording medium, The even number of coils are connected in series, and are paired for each of the two coils, and are connected so that a signal difference between the two coils is output. And outputs signals from both ends of a circuit composed of an even number of coils connected in series.

  According to the present invention, the magnetic head detects a change in the magnetic field when the magnetic recording medium relatively moves in each gap of the even number of head bodies arranged in the relative movement direction. Here, when the magnetic head is located in the disturbing magnetic field, a signal caused by the disturbing magnetic field is superimposed on each of the signals from the coils of the even number of head bodies. On the other hand, in the magnetic head, an even number of coils are connected in series, and two coils are paired, and are connected so that a difference between the two coils is output. ing. Therefore, between the two coils in the set, the signal caused by the disturbing magnetic field superimposed on the signal from one coil and the signal caused by the disturbing magnetic field superimposed on the signal from the other coil are canceled. . Therefore, if a signal is output from both ends of a circuit composed of an even number of coils connected in series, the magnetic head can change the magnetic field when the magnetic recording medium moves relatively, even in a disturbing magnetic field. It can be detected accurately. Further, the signal output from the magnetic head does not output the change in the magnetic field as the magnetic recording medium moves relative to the signal. Therefore, even if an attempt is made to acquire the magnetic information carried on the magnetic recording medium by taking out the signal output from the magnetic head by unauthorized means, it is difficult to acquire the magnetic information.

  In the present invention, it is desirable that the gaps of the even number of head bodies overlap when viewed from the relative movement direction of the magnetic recording medium. In this way, when the magnetic recording medium is a magnetic card or the like having a magnetic stripe, a change in the magnetic field due to the movement of the magnetic card (magnetic stripe) can be detected by an even number of head bodies.

  In the present invention, as the head body, a first head body including a first core including a first gap and a first coil wound around the first core, a second core including a second gap, and the second core. A second head body including a second coil wound around a core, and the first coil and the second coil are connected in series with the winding direction being opposite. be able to. In this way, the difference between the first signal from the first coil and the second signal from the second coil is obtained from both ends of the circuit composed of the first coil and the second coil connected in series. A differential signal is output. In the difference signal, since the signal caused by the disturbing magnetic field superimposed on the signal from the first coil and the signal caused by the disturbing magnetic field superimposed on the signal from the second coil are canceled, the magnetic head Even in the case, it is possible to accurately detect a change in the magnetic field when the magnetic recording medium relatively moves.

  In the present invention, it is desirable that the first core and the second core are the same member, and the first coil and the second coil are the same member with the winding direction being the reverse direction.

  In this case, the first core and the second core have the same shape and material, and the first coil and the second coil have the same coil wire thickness and the same number of turns. it can. If it does in this way, the difference signal which canceled the signal resulting from a disturbance magnetic field from the both ends of the 1st coil and the 2nd coil connected in series can be outputted.

  In the present invention, it is desirable that the first head body and the second head body are joined with a nonmagnetic member interposed therebetween. In this way, the positional relationship between the first head body and the second head body does not collapse in the head case.

In the present invention, each of the first core and the second core has a flat plate-like first arm portion extending in the orthogonal direction perpendicular to the relative movement direction with the thickness direction in the relative movement direction. A winding portion extending in the relative movement direction from one end portion of the first arm portion in the orthogonal direction and wound around the first coil or the second coil; and the first arm portion in the first arm portion. A facing portion that is opposed to the other end portion in the orthogonal direction by opening the first gap or the second gap, and a connecting portion that is connected to an end of the winding portion opposite to the first arm portion. The first head body and the second head body include the first arm part of the first core and the first arm part of the second core in the relative movement direction. And the two opposing firsts It is desirable that the are joined across the non-magnetic member between the portions. If it does in this way, since a 1st arm part and a 2nd arm part are arrange | positioned in the position which adjoins via a nonmagnetic member, a 1st gap and a 2nd gap are arrange | positioned in the position comparatively close. Here, if the first gap and the second gap for detecting the change of the magnetic field are close to each other, a signal caused by the disturbing magnetic field superimposed on the first signal output from the first coil, and the second coil The signal resulting from the disturbing magnetic field superimposed on the output second signal is the same. Therefore, it is easy to cancel a signal caused by the disturbing magnetic field in the differential signal.

  In the present invention, a plurality of head body groups each having the first head body and the second head body are provided, and the plurality of head body groups are arranged in a direction intersecting the relative movement direction. It can be. In this way, the magnetic head has the number of magnetic field reading channels corresponding to the number of sets of the head main body group.

  Next, a card reader of the present invention includes a card insertion slot into which a magnetic card having a magnetic track is inserted, a magnetic head for reading magnetic information for reading magnetic information from the magnetic track, and the magnetic insertion from the card insertion slot. A card conveyance path extending via a reading position by an information reading magnetic head, a detection position set between the card insertion slot and the reading position, and a magnetic field change by the magnetic card moving the detection position And a pre-head that detects that the magnetic card has been inserted into the card insertion slot, and the pre-head includes an even number of heads including a core having a gap and a coil wound around the core. A main body and a head case that houses the even number of head main bodies. Are arranged so as to be aligned in the relative movement direction of the magnetic card, and the even number of coils are connected in series, and are grouped for every two coils, and between the two coils that are grouped Is connected so that a difference between the signals is output, and signals from both ends of a circuit composed of an even number of coils connected in series are output.

  In the card reader of the present invention, even when a disturbing magnetic field is generated in the vicinity of the card insertion slot, a signal due to the disturbing magnetic field can be canceled for a signal output from the pre-head. Therefore, the pre-head can accurately detect the insertion of the magnetic card into the card insertion slot even in the disturbing magnetic field. Furthermore, the signal output from the pre-head does not output the change in the magnetic field when the magnetic card passes the detection position. Therefore, even if it is attempted to acquire the magnetic information carried on the magnetic recording medium by taking out the signal output from the pre-head by an unauthorized means, it is difficult to acquire the magnetic information.

  In the present invention, a magnetic field generator that generates a magnetic field in a region including the card insertion slot and the detection position can be provided. In this way, a disturbing magnetic field (magnetic field) can be generated in the vicinity of the card insertion slot. Therefore, even when a magnetic head for reading magnetic information is attached in the vicinity of the card insertion slot for illegal purposes, it is possible to prevent magnetic information from being read by the magnetic head for reading magnetic information.

  According to the present invention, the magnetic head can accurately detect a change in the magnetic field when the magnetic recording medium relatively moves even in the disturbing magnetic field. Therefore, a card reader equipped with the magnetic head of the present invention as a pre-head can accurately detect the insertion of the magnetic card into the card insertion slot.

It is explanatory drawing of the card reader of embodiment of this invention, and explanatory drawing of a magnetic card. It is the bottom view and side view of the pre-head of the card reader shown in FIG. It is sectional drawing of the pre head in the CC line | wire of FIG. It is sectional drawing of the pre head of a modification.

  Hereinafter, a magnetic head according to an embodiment of the present invention and a card reader on which the magnetic head is mounted as a pre-head will be described with reference to the drawings.

(overall structure)
FIG. 1A is an explanatory diagram of a card reader according to an embodiment of the present invention, and FIG. 1B is an explanatory diagram of a magnetic card from which magnetic information is read by the card reader. The card reader 1 according to this embodiment reads a magnetic card (magnetic recording medium) 3 including a magnetic stripe 2 and acquires magnetic information carried on the magnetic stripe 2. The card reader 1 is inserted into the card insertion slot 5, the magnetic information reading magnetic head 6, the card transport path 7 extending from the card insertion slot 5 via the reading position A by the pre-head 15, and the card insertion slot 5. A transport mechanism 8 for transporting the magnetic card 3 along the card transport path 7 is provided. The magnetic head 6 for reading magnetic information is arranged with the sensor surface 6a facing the card transport path 7 side. The transport mechanism 8 includes two pairs of transport rollers 9 that transport the magnetic card 3 between them. Each pair of transport roller pairs 9 is arranged on the upstream side and the downstream side of the reading position A, respectively. Further, the transport mechanism 8 includes a transport motor 10 as a drive source for the transport roller pair 9.

  Further, the card reader 1 confirms that the magnetic card 3 has been inserted into the card insertion slot 5 at the detection position B set between the card insertion slot 5 and the reading position A in the card transport path 7 and the detection position B. A pre-head (magnetic head of the present invention) 15 for magnetic detection and a magnetic field generator 16 for generating a disturbing magnetic field between the card insertion slot 5 and the reading position A in the card transport path 7 are provided. The detection position B is set closer to the card insertion slot 5 than the reading position A. The pre-head 15 is arranged with its sensor surface 15a facing the card transport path 7 side.

  When the card reader 1 detects that the magnetic card 3 has been inserted into the card insertion slot 5 based on the output from the pre-head 15, the card reader 1 drives the transport motor 10 to operate the transport mechanism 8. As a result, the magnetic card 3 is transported along the card transport path 7 and passes through the reading position A. When the magnetic card 3 passes the reading position A, the magnetic stripe 2 comes into sliding contact with the sensor surface 6a of the magnetic head 6 for reading magnetic information. Thus, the magnetic information reading magnetic head 6 detects a change in the magnetic field when the magnetic card 3 moves on the sensor surface 6a, and outputs the magnetic information carried on the magnetic card 3.

  The magnetic field generator 16 is installed as a countermeasure against skimming. That is, the magnetic field generator 16 generates a disturbing magnetic field 17 in an area including the card insertion slot 5 and the detection position B. As a result, the card reader 1 receives magnetic information from the magnetic card 3 inserted into the card transport path 7 from the card insertion port 5 by a magnetic information reading magnetic head attached in the vicinity of the card insertion port 5 for an illegal purpose. Prevent it from being acquired.

(Prehead)
2A is a bottom view when the pre-head 15 is viewed from the sensor surface 15a side, and FIG. 2B is a side view when the pre-head 15 is viewed from the passing direction through which the magnetic card 3 passes. . In FIG. 2B, the pre-head 15 is viewed from the second direction X2. FIG. 3 is a cross-sectional view of the pre-head taken along line CC in FIG. In the following description, as shown in FIG. 1, the posture in which the sensor surface 15a faces downward is defined as the reference posture of the pre-head 15, and the vertical direction in the reference posture is the vertical direction (orthogonal direction) Z of the pre-head 15. To do. Further, the passing direction in which the magnetic card 3 transported along the card transport path 7 passes through the sensor surface 15a of the pre-head 15 in a direction orthogonal to the up-down direction Z is defined as the front-rear direction (relative movement direction) X of the magnetic sensor. To do. Further, a direction orthogonal to the up-down direction Z and the front-rear direction X (the relative movement direction of the magnetic card 3 and the pre-head 15) is defined as the width direction (direction intersecting the passing direction) Y of the pre-head 15. In addition, one side of the pre-head 15 in the front-rear direction X is a first direction X1, and the other side is a second direction X2. For example, the first direction X1 is the direction in which the card insertion slot 5 is located, and the second direction X2 is the direction in which the magnetic head 6 for reading magnetic information is located.

  The pre-head 15 is a two-channel magnetic head that detects two of the three magnetic tracks 11 formed on the magnetic stripe 2 of the magnetic card 3. As shown in FIG. 2, the pre-head 15 includes a head case 21 and two head main body sets 22 that detect a change in magnetic field when each magnetic track 11 moves in the detection position B. The two head main body sets 22 are arranged in the width direction Y.

  The head case 21 is made of a soft magnetic material such as permalloy. The head case 21 includes a rectangular bottom plate portion 25 that defines the sensor surface 15a, and a rectangular tube portion 26 that extends from the outer peripheral edge of the bottom plate portion 25 upward Z2. The bottom plate portion 25 has a curved shape in which a central portion in the front-rear direction X projects outward. Two sensor surface openings 27 are provided in the center portion of the bottom plate portion 25 in the front-rear direction X. The two sensor surface openings 27 are elongated holes extending in the front-rear direction X, and are arranged in the width direction Y. An end (upper end) of the rectangular tube portion 26 opposite to the bottom plate portion 25 is an opening 28 for inserting the two head main body sets 22 into the head case 21.

  As shown in FIG. 3, each head body set 22 includes a nonmagnetic member 23, and a first head body 29 and a second head body 30 that are joined in the front-rear direction X with the nonmagnetic member 23 interposed therebetween.

  The nonmagnetic member 23 is a plate-like member having a constant thickness, and the thickness direction is directed to the front-rear direction X. The nonmagnetic member 23 is, for example, an aluminum plate. The first head body 29 is located on the non-magnetic member 23 in the first direction X1, and the second head body 30 is located on the non-magnetic member 23 in the second direction X2.

  The first head body 29 includes a first core 32 having a first gap 31, a first coil 34 wound around the first core 32 via a first coil bobbin 33, and a first direction of the first coil 34. A first one-side terminal 35 connected to the end of X1 and a first other-side terminal 36 connected to the end of the first coil 34 in the second direction X2 are provided.

  The first core 32 extends in the first direction X1 from a flat plate-like first arm portion 38 extending in the vertical direction Z with the thickness direction directed in the front-rear direction X, and the upper end portion of the first arm portion 38. A winding portion 39 around which the first coil 34 is wound, a lower arm portion of the first arm portion 38 and a first arm portion 38 in the winding portion 39 and an opposing portion 40 that is opposed to the first gap portion 31. Comprises a second arm portion 42 having a connecting portion 41 connected to the opposite end (end in the first direction X1). The winding part 39 is rod-shaped and has a rectangular cross-sectional shape. The second arm portion 42 includes a first extending portion 43 extending in the downward direction Z1 from the end portion in the first direction X1 of the winding portion 39, and a second extending portion extending in the second direction X2 from the lower end portion of the first extending portion 43. The projecting portion 44, the third extending portion 45 extending in the downward direction Z1 from the end portion in the second direction X2 of the second extending portion 44, and the protrusion projecting in the second direction X2 from the lower end portion of the third extending portion 45 Part 46 is provided. The upper end portion of the first extending portion 43 is the connecting portion 41, and the protruding portion 46 is the facing portion 40.

The first coil 34 is wound around the winding portion 39 via the first coil bobbin 33. The first coil 34 has its central axis oriented in the front-rear direction X. The first one-side terminal 35 is fixed to the end of the first coil bobbin 33 in the first direction X1. The first other side terminal 36 is fixed to the end of the first coil bobbin 33 in the second direction X2. The first one-side terminal 35 and the first other-side terminal 36 are parallel, and the first one-side terminal extends longer in the upper Z2 than the first other-side terminal.

  The second head body 30 includes a second core 52 having a second gap 51, a second coil 54 wound around the second core 52 via a second coil bobbin 53, and a first direction of the second coil 54. A second one-side terminal 55 connected to the end of X1 and a second other-side terminal 56 connected to the end of the second coil 54 in the second direction X2 are provided.

  The second core 52 has a flat plate-like first arm portion 58 extending in the up-down direction Z with the thickness direction directed in the front-rear direction X, and extends from the upper end of the first arm portion 58 toward the second direction X2. The winding portion 59 around which the second coil 54 is wound, the opposite portion 60 facing the lower end portion of the first arm portion 58 with a gap therebetween, and the opposite side of the first arm portion 58 in the winding portion 59. A second arm portion 62 having a connection portion 61 connected to the end (end in the second direction X2) is provided. The winding part 59 is rod-shaped and has a rectangular cross-sectional shape. The second arm portion 62 includes a first extending portion 63 extending in the downward direction Z1 from the end portion in the second direction X2 of the winding portion 59, and a second extending portion extending in the first direction X1 from the lower end portion of the first extending portion 63. The projecting portion 64, the third extending portion 65 extending in the downward direction Z1 from the end portion in the first direction X1 of the second extending portion 64, and the protrusion projecting in the first direction X1 from the lower end portion of the third extending portion 65 A portion 66 is provided. The upper end portion of the first extending portion 43 is a connecting portion 61, and the protruding portion 66 is a facing portion 60.

  The second coil 54 is wound around the winding portion 59 via the second coil bobbin 53. The second coil 54 has its central axis oriented in the front-rear direction X. The winding direction of the second coil 54 is opposite to the winding direction of the first coil 34 of the first head body 29. The second one-side terminal 55 is fixed to the end of the second coil bobbin 53 in the first direction X1. The second other-side terminal 56 is fixed to the end of the second coil bobbin 53 in the second direction X2. The second one-side terminal 55 and the second other-side terminal 56 are parallel, and the second other-side terminal 56 extends longer than the second one-side terminal 55 in the upper Z2.

  The first head body 29 and the second head body 30 are configured such that the first arm portion 38 of the first core 32 and the first arm portion 58 of the second core 52 face each other in the front-rear direction X, The non-magnetic member 23 is sandwiched between the first arm portions 58 and joined. Thereby, the first head body 29 and the second head body 30 are arranged side by side in the front-rear direction X. Accordingly, when viewed from the front-rear direction X (the relative movement direction of the magnetic card 3 and the pre-head 15), the first gap 31 of the first head body 29 and the second gap 51 of the second head body 30 overlap. Further, the first gap 31 of the first head body 29 and the second gap 51 of the second head body 30 are arranged side by side in a relatively close position in the front-rear direction X.

  The first other side terminal 36 of the first head body 29 and the second one side terminal 55 of the second head body 30 are electrically connected by a lead wire 70. Thereby, the 1st coil 34 and the 2nd coil 54 are connected in series in the state which made the winding direction the opposite direction. From the pre-head 15, signals are output from both ends of a circuit 50 including a first coil 34 and a second coil 54 connected in series.

  As shown in FIG. 2, the two head main body sets 22 are arranged in the width direction Y in the head case 21. Thus, the first gap 31 and the second gap 51 of each head body set 22 are exposed to the outside of the head case 21 from each sensor surface opening 27 provided in the bottom plate portion 25 of the head case 21. The inside of the head case 21 is filled with resin.

(Detection of magnetic card by pre-head)
As shown in FIG. 1, when the magnetic card 3 is inserted into the card insertion slot 5, the magnetic stripe 2 comes into sliding contact with the sensor surface 15 a of the pre-head 15 at the detection position B. When the magnetic stripe 2 moves on the sensor surface 15a, the pre-head 15 detects a change in the magnetic field when the magnetic stripe 2 passes through the first gap 31 and the second gap 51 of each head body set 22, and each head body Detection signals are output from the first one-side terminal 35 and the second other-side terminal 56 of the set 22.

  When the detection signal is output, the card reader 1 determines whether or not the magnetic card 3 has been inserted into the card insertion slot 5 based on the detection signal. When the card reader 1 determines that the magnetic card 3 has been inserted, the card reader 1 drives the transport motor 10. As a result, the magnetic card 3 is transported along the card transport path 7 via the reading position A. The magnetic information reading magnetic head 6 acquires a magnetic information from the magnetic track 11 by detecting a change in the magnetic field when the magnetic card 3 passes the reading position A.

  Here, in this example, the magnetic field generator 16 generates the disturbing magnetic field 17 in an area including the card insertion slot 5 and the detection position B. Therefore, if the detection signal output from the pre-head 15 includes a signal due to the disturbing magnetic field 17, it is accurately determined whether or not the magnetic card 3 has been inserted based on the detection signal from the pre-head 15. The problem that it becomes impossible to occur.

  In response to such a problem, the pre-head 15 includes a first head main body 29 and a second head in which the change in the magnetic field when the magnetic card 3 moves at the detection position B is arranged in the moving direction of the magnetic card 3 (front-rear direction X). It is detected by the main body 30. Further, the winding direction of the first coil 34 wound around the first core 32 of the first head body 29 and the winding direction of the second coil 54 wound around the second core 52 of the second head body 30 Is the reverse direction, and the first coil 34 and the second coil are connected in series. Therefore, the first one-side terminal 35 connected to the opposite end of the first coil 34 to the second coil 54 and the second one of the second coil 54 connected to the opposite end of the first coil 34. 2 The detection signal output from the other terminal 56 is the difference between the first signal from the first coil 34 of the first head body 29 and the second signal from the second coil 54 of the second head body 30. It becomes a differential signal.

  Here, when the pre-head 15 is located in the disturbing magnetic field 17, a signal due to the disturbing magnetic field 17 is superimposed on each of the first signal from the first coil 34 and the second signal from the second coil 54. However, the detection signal output from the pre-head 15 is a differential signal that is the difference between the first signal and the second signal. Accordingly, in the detection signal (difference signal) output from the pre-head, the signal caused by the disturbing magnetic field 17, that is, the signal superimposed on both the first signal and the second signal is canceled. Therefore, the pre-head 15 can accurately detect a change in the magnetic field when the magnetic card 3 moves in the detection position B even in the disturbing magnetic field 17. Accordingly, the card reader 1 can accurately determine whether or not the magnetic card 3 has been inserted into the card insertion slot 5.

  The detection signal (difference signal) output from the pre-head 15 is the difference between the first signal and the second signal, and does not output the change in the magnetic field when the magnetic card 3 moves the detection position B as it is. Absent. Therefore, even if the detection signal output from the pre-head 15 is taken out by unauthorized means to acquire the magnetic information carried on the magnetic card 3, it is difficult to acquire the magnetic information.

Furthermore, in this example, the first head main body 29 and the second head main body 30 constituting each head main body set 22 are configured using the same core and the same coil. Further, the first gap 31 of the first head body 29 and the second gap 51 of the second head body 30 are disposed at relatively close positions. Here, if the first head body 29 and the second head body 30 are configured using the same core and the same coil, the first signal from the first coil 34 and the second signal from the second coil 54 are used. Is the same signal. Further, if the first gap 31 and the second gap 51 for detecting the change in the magnetic field are close to each other, a signal caused by the disturbing magnetic field 17 superimposed on the first signal output from the first coil 34, and the second The signal resulting from the disturbing magnetic field 17 superimposed on the second signal output from the coil 54 is a similar signal. Therefore, if the difference between the first signal output from the first coil 34 and the second signal output from the second coil 54 is taken, the signal caused by the disturbing magnetic field 17 can be canceled.

  In this example, the first head body 29 and the second head body 30 are joined with the nonmagnetic member 23 interposed therebetween. Therefore, the positional relationship between the first head main body 29 and the second head main body 30 in the head case 21 does not collapse.

  Here, the nonmagnetic member 23 may be a ceramic plate. In this case, the wear resistance of the pre-head 15 can be improved as compared with the case where an aluminum plate is used as the nonmagnetic member 23.

  In the above example, each head main body set 22 includes two head main bodies (first head main body 29 and second head main body 30), but each head main body set 22 accommodated in the head case 21 includes four head main body sets 22. The even number of head bodies may be provided.

  FIG. 4 is a cross-sectional view of a pre-head in which the head main body set 22 includes four head main bodies. The pre-head 80 of this example includes a third head body 83 and a fourth head body 84 arranged in the front-rear direction X between the first head body 29 and the second head body 30 in the front-rear direction (relative movement direction) X. Prepare.

  The third head body 83 includes a third core 86 having a third gap 85, a third coil 88 wound around the third core 86 via a third coil bobbin 87, and a first direction of the third coil 88. A third one-side terminal 89 connected to the end of X1 and a third other-side terminal 90 connected to the end of the third coil 88 in the second direction X2 are provided. The fourth head body 84 includes a fourth core 92 having a fourth gap 91, a fourth coil 94 wound around the fourth core 92 via a fourth coil bobbin 93, and a first direction of the fourth coil 94. A fourth one-side terminal 95 connected to the end of X1 and a fourth other-side terminal 96 connected to the end of the fourth coil 94 in the second direction X2 are provided. When viewed from the front-rear direction X (the relative movement direction of the magnetic card 3 and the pre-head 15), the first gap 31 of the first head body 29, the second gap 51 of the second head body 30, and the first gap of the third head body 83. The third gap 85 and the fourth head body 84 overlap the fourth gap 91.

  The third core 86 and the fourth core 92 are the same member. That is, the third core 86 and the fourth core 92 are made of the same magnetic material. The third core 86 and the fourth core 92 have the same shape. Moreover, the 3rd coil 88 and the 4th coil 54 are the same members which made the winding direction the reverse direction. That is, the third coil 88 and the fourth coil 54 have the same coil wire thickness and the same number of turns.

Here, the third one-side terminal 89 of the third head body 83 is electrically connected to the first other-side terminal 36 of the first head body 29 by the lead wire 70. The third other side terminal 90 of the third head main body 83 and the fourth first side terminal 95 of the fourth head main body 84 are electrically connected by a lead wire 70. Further, the fourth other-side terminal 96 of the fourth head body 84 is electrically connected to the second one-side terminal 55 of the second head body 30 by the lead wire 70. That is, the coils 34, 54, 88, 94 of the four head bodies 29, 30, 83, 84 are connected in series. In addition, the first coil 34 of the first head body 29 and the second coil 54 of the second head body 30 are paired, and a signal difference between the two coils 34 and 54 is output. Connected so that. That is, the first coil 34 and the second coil 54 are connected in series with the winding direction being reversed. Similarly, the third coil 88 of the third head main body 83 and the coil 94 of the fourth head main body 84 are set as a pair so that a difference in signal between the two coils 88 and 94 is output. It is connected. That is, the third coil 88 and the fourth coil 94 are connected in series with the winding direction being reversed. The pre-head 80 includes a first one-side terminal 35 of the first head body 29 that is the both ends of a circuit 98 composed of the first coil 34, the second coil 54, the third coil 88, and the fourth coil 64. A signal is output from the second other side terminal 56 of the head body 30.

  Also in this example, a signal from one coil is transmitted between the two coils in the set (between the first coil 34 and the second coil 54 and between the third coil 88 and the fourth coil 94). The signal caused by the superimposed disturbance magnetic field and the signal caused by the disturbance magnetic field superimposed on the signal from the other coil are canceled. Therefore, if a signal is output from both ends of the circuit 98 composed of a plurality of coils 34, 54, 88, 94 connected in series, the pre-head 15 moves relative to the magnetic card 3 even in the disturbing magnetic field. The change in the magnetic field can be accurately detected.

  In the pre-head 80, if the winding direction of the first coil 34 and the second coil 54 is opposite and the winding direction of the third coil 88 and the fourth coil 64 is opposite, the first coil 34 and the second coil The winding direction of the three coils 88 may be the same direction or the reverse direction. Therefore, for example, in the pre-head 80 described above, the first other side terminal 36 of the first head main body 29 and the third other side terminal 90 of the third head main body 83 are connected, and the third one side of the third head main body 83 is connected. The terminal 89 and the fourth one side terminal 95 of the fourth head body 84 are connected, the fourth other side terminal 96 of the fourth head body 83 and the second other side terminal 56 of the second head body 30 are connected, Signals can also be output from the first one-side terminal 35 of the first head body 29 and the second one-side terminal 55 of the second head body 30.

1 ... card reader 3 ... magnetic card (magnetic recording medium)
5 ... Card insertion slot 6 ... Magnetic information reading magnetic head 7 ... Card transport path 11 ... Magnetic track 15, 80 ... Pre-head (magnetic head)
16 ... Magnetic field generator 21 ... Head case 22 ... Head body assembly 23 ... Non-magnetic member 29 ... First head body 30 ... Second head body 31 ... First gap 32 ... 1st core 34 ... 1st coil 38 ... 1st arm part 39 ... Winding part 40 ... Opposing part 41 ... Connection part 42 ... 2nd arm part 50 98 ... Circuit 51 ... Second gap 52 ... Second core 54 ... Second coil 83 ... Third head body 84 ... Fourth head body 88 ... Third coil 94 ... 4th coil A ... reading position B ... detection position X ... front-back direction (relative movement direction)

Claims (10)

In a magnetic head that detects a change in a magnetic field when a magnetic recording medium moves relatively,
An even number of head bodies comprising a core with a gap and a coil wound around the core;
A head case that houses the even number of head bodies,
The even number of head bodies are arranged so that the gaps of the head bodies are aligned in the relative movement direction of the magnetic recording medium,
The even number of coils are connected in series, and are paired for each of the two coils, and are connected so that a signal difference between the two coils is output. And
A magnetic head which outputs signals from both ends of a circuit composed of an even number of coils connected in series. In claim 1,
The magnetic head, wherein the gaps of the even number of head bodies overlap when viewed from the relative movement direction of the magnetic recording medium. In claim 2,
As the head main body, a first core including a first core including a first gap and a first coil wound around the first core, and a second core including a second gap and the second core wound around the second core. A second head body comprising a second coil,
The magnetic head according to claim 1, wherein the first coil and the second coil are connected in series with the winding direction being opposite. In claim 3,
The first core and the second core are the same member,
The magnetic head according to claim 1, wherein the first coil and the second coil are the same member whose winding direction is the reverse direction. In claim 4,
The first core and the second core have the same shape and material,
The magnetic head characterized in that the first coil and the second coil have the same coil wire thickness and the same number of turns. In claim 4 or 5,
The magnetic head according to claim 1, wherein the first head main body and the second head main body are joined with a nonmagnetic member interposed therebetween. In claim 6,
Each of the first core and the second core has a flat plate-like first arm portion extending in an orthogonal direction perpendicular to the relative movement direction with the thickness direction in the relative movement direction, and the first arm. A winding portion extending in the relative movement direction from one end portion of the portion in the orthogonal direction, and the other portion of the first arm portion in the orthogonal direction extending around the first coil or the second coil A second portion provided with a facing portion that is opposed to the end portion of the winding portion by opening the first gap or the second gap, and a connecting portion that is connected to an end of the winding portion opposite to the first arm portion. With arm parts,
The first head main body and the second head main body are configured to cause the first arm portion of the first core and the first arm portion of the second core to face each other in the relative movement direction, and A magnetic head, wherein the non-magnetic member is sandwiched between the first arm portions. In any one of claims 3 to 7,
A plurality of head body groups each including the first head body and the second head body;
The plurality of sets of head body groups are arranged in a direction crossing the relative movement direction. A card insertion slot into which a magnetic card having a magnetic track is inserted;
A magnetic head for reading magnetic information for reading magnetic information from the magnetic track;
A card transport path extending from the card insertion opening via a reading position by the magnetic information reading magnetic head;
A detection position set between the card insertion slot and the reading position;
A pre-head that detects a change in a magnetic field by the magnetic card that moves the detection position and detects that the magnetic card is inserted into the card insertion slot,
The pre-head includes an even number of head main bodies including a core having a gap and a coil wound around the core, and a head case that houses the even number of head main bodies, and the even number of head main bodies are The gaps of the respective head bodies are arranged so as to be aligned in the relative movement direction of the magnetic card, and the even number of the coils are connected in series and are set as a set every two coils. Further, the two coils are connected so as to output a difference between each other, and signals from both ends of a circuit composed of an even number of coils connected in series are output. Card reader. In claim 9,
A card reader, comprising: a magnetic field generator for generating a magnetic field in an area including the card insertion slot and the detection position.

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