JP6111466B2 - Magnetic information processing equipment - Google Patents

Description

  The present invention relates to a magnetic information processing apparatus and a magnetic information processing method for performing processing such as reproducing recorded information on a magnetic recording medium such as a magnetic card.

As a card that is used in a financial institution such as a bank and realizes cashless, personal authentication, etc., there is a magnetic card in which a magnetic stripe is formed on the surface of a plastic substrate.
Recording and reproduction of magnetic information with respect to the magnetic card is performed by a magnetic card reader (including a magnetic card reader / writer) which is a magnetic information processing apparatus.

  The magnetic card reader reads / writes magnetic information recorded on the magnetic card or writes new magnetic information on the magnetic card by contacting / sliding the magnetic head on the magnetic stripe on the surface of the magnetic card.

By the way, in a magnetic card reader, there are cases where external magnetic noise, motor noise or the like adversely affects the magnetic head as magnetic noise and magnetic information cannot be read accurately.
More specifically, the external magnetic noise is an electric signal output from the magnetic head when the magnetic head is not reading magnetic information formed on the magnetic card.
Therefore, Patent Document 1 describes a technique for detecting whether or not the external magnetic noise exceeds a predetermined amount and transmitting information on whether or not the reading process cannot be performed accurately to the host device.

Magnetic card readers include a manual type in which a magnetic card is manually scanned, and a motor type as a method of conveying a magnetic card.
In the motor-type magnetic card reader, the motor is driven to take in the magnetic card, and noise is generated from the motor in accordance with this driving.
In particular, when a PWM control method is employed as a motor control method, for example, noise increases and is easily affected by magnetic noise, which may cause a read error by the magnetic head.

  Patent Document 2 has a PWM drive control circuit that receives a control signal from a control circuit and drives the drive motor by PWM control using a predetermined PWM carrier signal, while the drive motor carries a magnetic card. By changing the frequency of the PWM carrier signal, for example, 2000 Hz from 2000 Hz to, for example, 8000 Hz based on the control signal from the control circuit, the motor noise can be reduced as compared with a mechanical motor noise countermeasure such as a magnetic shield. The technology that can do is described.

JP 2000-298713 A JP 2006-179060 A

  However, in the technique described in Patent Document 1, since only (external) magnetic noise is detected, it is not a fundamental measure against a reading error.

Moreover, in the technique described in Patent Document 2, although it is possible to reduce motor noise as compared with mechanical motor noise countermeasures such as a magnetic shield, it is difficult to reduce noise or the like during conveyance of a magnetic card, It is difficult to sufficiently improve the reading performance against magnetic noise.
Even when the magnetic card is not conveyed, there is a problem that the magnetic head erroneously determines magnetic noise as magnetic information.

  An object of the present invention is to provide a magnetic information processing apparatus and a magnetic information processing method that are less susceptible to magnetic noise due to external magnetic noise, motor noise, and the like and that can suppress reading errors caused by a magnetic head.

A magnetic information processing apparatus of the present invention includes a magnetic head for reading magnetic information recorded on a magnetic recording medium, an amplifying unit capable of amplifying different magnetic signals detected by the magnetic head, and an output from the amplifying unit. A magnetic information reading unit for reading and demodulating magnetic information recorded on the magnetic recording medium from a magnetic signal detected by the magnetic head, and a reading for reading the magnetic information recorded on the magnetic recording medium by the magnetic head A switching unit that switches the gain of the amplifying unit between the range and the reading range; a transport path in which the magnetic head is disposed; and the presence and position of the magnetic recording medium in the transport path A detection sensor for detecting the magnetic recording medium, and the conveyance of the magnetic recording medium can be controlled according to a detection result of the detection sensor, and the detection sensor detects the magnetic recording medium. It has a controllable controller sensitivity is at a level which detects that issued, wherein the amplifying section, when the magnetic head is within the range reading reads magnetic information recorded on the magnetic recording medium A first gain capable of demodulating the magnetic information; and a second gain outside a reading range in which the magnetic head reads the magnetic information recorded on the magnetic recording medium. The second gain from the magnetic head Ri gain der to level the magnetic signal output is not processed by the magnetic information reading section, wherein the control unit, the gain of the amplifying unit previously fixed to the first gain, the magnetic recording medium is a magnetic When the magnetic recording medium is outside the reading range of the magnetic information of the head, the detection sensitivity, which is a level for detecting the magnetic recording medium conveyed on the conveying path, is higher than the first sensitivity when the magnetic recording medium is within the reading range of the magnetic head. There is controlled to the second sensitivity.

  According to the magnetic information processing apparatus of the present invention, the magnetic information processing apparatus has a second gain other than when the magnetic head reads (demodulates) the magnetic information recorded on the magnetic recording medium at the switching unit. Since switching is performed (variable), it is difficult to be affected by magnetic noise, and reading errors caused by the magnetic head can be suppressed.

  Further, in the magnetic information processing apparatus of the present invention, the magnetic head is disposed, and includes a conveyance path through which the magnetic recording medium is conveyed, and a detection sensor that detects a position of the magnetic recording medium in the conveyance path, The switching unit preferably switches the gain of the amplifying unit according to the detection result of the detection sensor.

  According to the present invention, since the magnetic information processing apparatus can detect the reading range of the magnetic head by detecting the position of the magnetic information recording medium, the magnetic information processing apparatus is hardly affected by the magnetic noise and the reading error by the magnetic head. Can be reliably suppressed.

  In addition, when the magnetic signal is out of the reading range, the magnetic signal output from the magnetic head is processed with the second gain. Therefore, the magnetic signal is less affected by magnetic noise, and reading errors caused by the magnetic head can be more reliably suppressed. it can.

  Furthermore, in the magnetic information processing apparatus of the present invention, it is preferable that the magnetic information processing apparatus includes a drive unit that transports the magnetic recording medium along the transport path.

  According to the present invention, in the magnetic information processing apparatus, the switching unit switches (varies) to the second gain other than when the magnetic head reads and demodulates the magnetic information recorded on the magnetic recording medium. The reading error by the magnetic head can be suppressed without being affected by the magnetic noise generated from the magnetic head.

  According to the present invention, the magnetic information processing apparatus is at a level at which the control unit detects the magnetic recording medium conveyed along the conveyance path when the magnetic recording medium is outside the region passing through the arrangement position of the magnetic head. The detection sensitivity is controlled to the second sensitivity by lowering the detection sensitivity from the first sensitivity in the region where the magnetic recording medium passes through the magnetic head arrangement position. As a result, when the magnetic recording medium is out of the reading range of the magnetic head, the magnetic recording medium is difficult to be detected and recognized at an incorrect position or timing. As a result, the drive unit, the magnetic head, and the like are driven with high precision and accuracy other than when they are in the region passing through the arrangement position, and thus are less susceptible to magnetic noise and suppress reading errors caused by the magnetic head. be able to.

A magnetic information processing method according to an aspect of the present invention reads magnetic information recorded on a magnetic recording medium conveyed along a conveyance path with a magnetic head disposed in the conveyance path, and amplifies a magnetic signal detected by the magnetic head. A magnetic information processing method for amplifying with a gain designated by a unit and reading and demodulating magnetic information recorded on the magnetic recording medium from a magnetic signal detected by the magnetic head output from the amplification unit, A switching step for switching the gain of the amplifying unit between a reading range in which the magnetic head reads the magnetic information recorded on the magnetic recording medium and outside the reading range, and detecting the presence and position of the magnetic recording medium in the transport path The conveyance of the magnetic recording medium can be controlled according to the detection result of the detection sensor to detect the level at which the detection sensor detects the magnetic recording medium. Has a control step capable of controlling the sensitivity is, the, in the switching step, the reading range reads magnetic information of the magnetic head is recorded on the magnetic recording medium, the possible demodulates the magnetic information The gain is switched to 1 gain and outside the reading range where the magnetic head reads the magnetic information recorded on the magnetic recording medium, the gain is switched to the second gain at which the magnetic signal output from the magnetic head cannot be read and demodulated. In the control step, the gain of the amplifying unit is fixed to the first gain, and when the magnetic recording medium is outside the magnetic information reading range of the magnetic head, the magnetic material conveyed on the conveyance path is used. The detection sensitivity, which is a level for detecting the recording medium, is controlled to a second sensitivity lower than the first sensitivity when the magnetic recording medium is within the reading range of the magnetic head .

  According to the magnetic information processing method of the present invention, in the switching step, the magnetic head is switched (varied) to the second gain other than when reading (demodulating) the magnetic information recorded on the magnetic recording medium. It is difficult to be affected by magnetic noise, and reading errors due to the magnetic head can be suppressed.

  In the magnetic information processing method of the present invention, the position of the magnetic recording medium in a transport path in which the magnetic head is disposed and the magnetic recording medium is transported is detected by a detection sensor, and the detection sensor is It is preferable to switch the gain of the amplifying unit according to the detection result.

  According to the present invention, the magnetic information processing method can detect the reading range of the magnetic head by detecting the position of the magnetic information recording medium. Can be reliably suppressed.

  In addition, when the magnetic signal is out of the reading range, the magnetic signal output from the magnetic head is processed with the second gain. Therefore, the magnetic signal is less affected by magnetic noise, and reading errors caused by the magnetic head can be more reliably suppressed. it can.

  Furthermore, in the magnetic information processing method of the present invention, it is preferable that the magnetic recording medium is transported along the transport path by a driving unit.

  According to the present invention, in the magnetic information processing method, in the switching step, the magnetic head switches (varies) to the second gain other than when reading and demodulating the magnetic information recorded on the magnetic recording medium. The reading error by the magnetic head can be suppressed without being affected by the magnetic noise generated from the magnetic head.

  According to the present invention, it is difficult to be affected as magnetic noise, and it is possible to suppress reading errors caused by the magnetic head.

It is a block diagram which shows the structural example of the magnetic card reader as a magnetic information processing apparatus which concerns on embodiment of this invention. It is a figure which shows the signal processing waveform of the principal part of the magnetic card reader of FIG. It is a plane sectional view showing simply the structure of the magnetic card reader concerning the embodiment of the present invention. It is FIG. 1 which shows a mode that a magnetic card actually moves along a card conveyance path. It is FIG. 2 which shows a mode that a magnetic card actually moves along a card conveyance path. It is FIG. 3 which shows a mode that a magnetic card actually moves along a card conveyance path. FIG. 4 is a fourth diagram showing how the magnetic card actually moves along the card conveyance path. FIG. 5 is a fifth diagram showing how the magnetic card actually moves along the card conveyance path. FIG. 6 is a first flowchart for explaining gain control of a differential amplifier circuit related to detection signals of respective sensors accompanying card conveyance in the magnetic card reader according to the present embodiment. It is a 2nd flowchart for demonstrating the gain control of the differential amplifier circuit relevant to the detection signal of each sensor accompanying card conveyance in the magnetic card reader which concerns on this embodiment. It is a conceptual diagram which shows the format of the magnetic information recorded on a magnetic stripe. It is a figure which shows each code | cord | chord and the waveform level pattern corresponding to this.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In this embodiment, a magnetic card reader (including a magnetic card reader / writer) that reproduces or records magnetic information recorded on a magnetic card or the like as a magnetic recording medium will be described as an example of the magnetic information processing apparatus.
In this embodiment, an example will be described in which F and 2F signals corresponding to “0” and “1” signals magnetically recorded by the frequency modulation method are read and reproduced.
However, the present technology is not limited to the F2F method, and various methods such as the F3F method, the NRZI method, and the MFM method can be applied.

In the following, first, an outline of the configuration and functions of a signal processing system and a drive system that perform gain adjustment of the amplification unit accompanying the characteristic magnetic card conveyance of the magnetic card reader according to the present embodiment will be described, and then the magnetic card reader A specific structure of the card transport system and the like will be described. Then, the gain control of the amplifier related to this signal processing system and structure will be described.
In this case, the magnetic card reader is used. However, in addition to the magnetic information reproducing function, there may be a magnetic information recording function.

[Outline of signal processing system of magnetic card reader]
FIG. 1 is a block diagram showing a configuration example of a magnetic card reader as a magnetic information processing apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing signal processing waveforms of the main part of the magnetic card reader of FIG.
FIG. 3 is a plan sectional view schematically showing the structure of the magnetic card reader 10 according to the embodiment of the present invention.

As shown in FIG. 1, the magnetic card reader 10 includes a magnetic head 11, a differential amplifier circuit 12 as an amplifier, a magnetic information reader 13, a card transport path 14, and a magnetic stripe mp as a magnetic recording medium. A card transport unit 15 that transports the card MC along the card transport path 14 and a drive motor (M) 16 as a drive unit that drives the card transport unit 15 are provided.
Further, the magnetic card reader 10 includes a detection sensor group 17 for detecting the presence / absence of the magnetic card MC in the card transport path 14 and a card transport position, a control unit 18 such as a CPU, and an interface circuit 19. Yes.

In the magnetic card reader 10 of the present embodiment, the control unit 18 switches the gain of the differential amplifier circuit 12 between when the magnetic head 11 reads magnetic information recorded on the magnetic card MC and when the magnetic head 11 does not read the magnetic information. 181.
The differential amplifier circuit 12 receives the first gain G1 that can demodulate the magnetic information when the magnetic head 11 reads the magnetic information recorded on the magnetic card MC, and the magnetic information that the magnetic head 11 records on the magnetic card MC. And a second gain G2 other than the case of reading (switching is controlled).
That is, the switching unit 181 switches the gain of the differential amplifier circuit 12 to the first gain G1 or the second gain G2 depending on whether or not the magnetic information is being read under the control of the control unit 18.
In other words, the switching unit 181 determines whether or not the gain of the differential amplifier circuit 12 is in a state of reading magnetic information according to the detection result of the detection sensor group 17 under the control of the control unit 18. Depending on the determination, the first gain G1 or the second gain G2 is switched.
The second gain G2 is a gain at which the magnetic signal output from the magnetic head 11 cannot be processed by the magnetic information reading unit 13.

As shown in FIG. 2A, for example, the magnetic head 11 reads magnetic recording information recorded on the magnetic card MC, which is a magnetic recording medium, by the F2F modulation method as an analog signal S11.
The analog signal S11 of the magnetic recording information read by the magnetic head 11 is supplied to the differential amplifier circuit 12.

The differential amplifier circuit 12 is composed of an operational amplifier, and amplifies the analog signal S11 read and reproduced by the magnetic head 11 to an appropriate level under the gain control of the control unit 18, and is shown in FIG. An amplified analog signal (amplified signal) S12 as shown is output to the magnetic information reading unit 13.
In the differential amplifier circuit 12, for example, an intermediate value VM of the output analog signal S12 is set based on a reference voltage Vref supplied by a reference voltage circuit (not shown).
The differential amplifier circuit 12 performs gain control so that the amplitude of the signal is set to 1/4 of the full range, for example.
In this case, the gain of the differential amplifier circuit 12 is controlled by the control unit 18 to the first gain G1 that can output a first level signal that can be properly processed by the magnetic information reading unit 13 at the subsequent stage. Is done.
Before and after reading the read waveform in FIG. 2B, the gain of the differential amplifier circuit 12 is controlled to a lower second gain G2 by the first gain G1. The output of the differential amplifier circuit 12 at the second gain G2 is at a level in the VM or in the vicinity thereof and cannot be recognized as a signal, or the magnetic analog signal S11 output from the magnetic head 11 is a magnetic information reading unit. 13 is a signal of a level that cannot be processed, and it is possible to reduce the magnetic noise during the period excluding reading by the magnetic head 11.

That is, the gain of the differential amplifier circuit 12 is controlled by the control unit 18 as follows.
When the magnetic card MC is outside the range in which the magnetic information of the magnetic head 11 can be read, the differential amplifier circuit 12 is controlled to decrease the amplification gain until it is within the range.
The range in which magnetic information can be read includes a range in which the magnetic head 11 can sense magnetic information as a signal.
In the present embodiment, for example, the magnetic head 11 can be a section corresponding to the magnetic stripe of the magnetic card MC. However, the entire magnetic stripe is not limited to a readable range, and a range (area) in which a signal to be read is recorded can be defined as a readable range.

In the present embodiment, specifically, in order to facilitate understanding, the differential amplifier circuit 12 is slid magnetically by the control unit 18 while the magnetic head 11 is in contact with the magnetic card MS (the magnetic stripe). When the information is out of the reading range (hereinafter referred to as “reading range”), the gain is controlled to be lowered until the information is within the reading range.
In other words, the differential amplifier circuit 12 includes the first gain G1 that can demodulate the magnetic information when the magnetic head 11 reads the magnetic information recorded on the magnetic card MC (when it is within the reading range), and the magnetic head 11. Includes a second gain G2 other than when reading magnetic information recorded on the magnetic card MC (outside of the reading range).

  In the present embodiment, specifically, the reading range is a range in which the magnetic card MC is detected by either the photosensor PD3 of FIG. 3 and the photosensor PD4 described later, that is, in FIG. When the MC is inserted from the left side (insertion slot) and conveyed toward the right side (back), the photosensor PD3 detects the leading edge of the magnetic card MC, and the trailing edge of the magnetic card MC is detected by the photosensor PD4. Between.

In the present embodiment, the gain of the differential amplifier circuit 12 is controlled to a second gain G2 that is lower than the first gain G1 that can maintain a signal level that allows signal processing when the gain is outside the reading range.
In the present embodiment, the second gain G2 lower than the first gain G1 includes the gain G0, that is, the gain when the amplifier circuit is not passed.
In order to realize this gain G0, it is possible to adopt a configuration in which switching between the case of passing through the amplifier circuit and the case of not passing through the amplifier circuit is possible by the control signal from the control unit 18.
Hereinafter, when the gain of the differential amplifier circuit 12 is outside the reading range, the gain is switched to a second gain G2 lower than the first gain G1 capable of maintaining a signal level that can be processed by the switching unit 181 of the control unit 18. It will be described as being controlled.

In the present embodiment, the first gain G1 and the second gain G2 are defined as follows.
As described above, the second gain G2 is lower than the first gain G1, and can be expressed as follows using an inequality.
First gain G1> second gain G2

The first gain G1 is a level at which the magnetic head 11 outputs magnetic information recorded in the magnetic stripe as a magnetic analog signal and is amplified until the output signal is demodulated.
On the other hand, the second gain G2 is a value that is not easily affected by magnetic noise, that is, a level at which an output signal from the magnetic head 11 cannot be processed (recognized) by the peak detection circuit 131.
The first gain G1 and the second gain G2 are set based on the characteristics of the magnetic head 11, and are set based on calculations, experiments, and the like.

More specifically, the gain of the differential amplifier circuit 12 is controlled by the control unit 18 to the second gain G2 until, for example, the magnetic card MC reaches the reading range, and to the first gain G1 while passing through the reading range. The second gain G2 is controlled after passing through the reading range.
In other words, the gain of the differential amplifier circuit 12 is controlled by the control unit 18 so that when the signal is within the reading range, the amplified signal is controlled to a first level that allows signal processing, and when the gain is outside the reading range. The second level is controlled to be lower than the first level.

  The differential amplifier circuit 12 can also be configured to have an automatic gain control (AGC) function.

The magnetic information reading unit 13 has a function of reading and demodulating magnetic information recorded on the magnetic card MC from a magnetic signal detected by the magnetic head 11 output from the differential amplifier circuit 12.
The magnetic information reading unit 13 in FIG. 1 shows the simplest configuration example, but various modes are possible. It is also possible to configure the differential amplifier circuit 12 as included in the magnetic information reading unit 13.

  The magnetic information reading unit 13 of FIG. 1 includes a peak detection circuit 131 and a demodulation circuit 132.

The peak detection circuit 131 receives the output signal of the differential amplifier circuit 12 through, for example, a band pass filter.
For example, as shown in FIG. 2C, the peak detection circuit 131 inverts the output at the peak point of the amplified signal, obtains a rectangular wave signal S131, and supplies it to the demodulation circuit 132.
This rectangular wave signal S131 is a frequency-modulated (F2F modulated) signal.
The demodulating circuit 132 performs digital signal processing on the rectangular wave signal S131 and, for example, a read clock signal (clock pulse for sampling demodulated data) output at bit breaks or a read data signal (demodulated) indicating the bit data. Data) is output to the control unit 18 and the interface circuit 19.

For the peak detection circuit 131, for example, various circuits such as a differentiation circuit, an integration circuit, and a digital system can be applied.
The demodulation circuit 132 can employ various methods such as a so-called one-shot method, a multiple interval method, and a pattern matching method.

  In the card transport path 14, the magnetic head 11 is disposed, and the magnetic card MC is transported by the card transport unit 15 toward the position where the magnetic head 11 is disposed or away from the position where the magnetic head 11 is disposed.

  The card transport unit 15 transports the magnetic card MC along the card transport path 14 by driving of a drive motor 16 as a drive unit.

The drive motor 16 is driven and controlled by the control unit 18 and drives the card transport unit 15 to transport the magnetic card MC.
As a motor control method, for example, a PWM control method is adopted, and the drive motor 16 is subjected to PWM control by the control unit 18.

When this PWM control method is adopted, noise tends to increase, and it is easily affected by external magnetic noise, which may cause a reading error by the magnetic head.
Specifically, when the drive motor is operated to take in the magnetic card MC, noise is generated from the drive motor. When the drive motor control method is the PWM method, noise increases, and noise of several k to several tens of kHz is generated.
Since the frequency of the magnetic data signal is several hundred Hz to several kHz and is close to the motor noise frequency, it is easily affected by motor noise.

Therefore, in this embodiment, as will be described later, in order to minimize the influence of noise, the drive motor 16, the differential amplifier circuit 12, and the magnetic information reading unit 13 are separated with the magnetic head 11 interposed therebetween. Placed in position.
The differential amplifier circuit 12 and the magnetic information reading unit 13 are mounted on a circuit board 30. The circuit board 30 is attached to one side plate on the magnetic head side in the example of FIG.
In the example of FIG. 3, the drive motor 16 is disposed on the other side plate side, and as is apparent from the figure, the drive motor 16, the differential amplifier circuit 12, and the magnetic information reading unit 13 sandwich the magnetic head 11. It is arranged at a separated position.

In this embodiment, it is difficult to be affected as magnetic noise, and reading errors by the magnetic head 11 can be suppressed. In other words, the magnetic noise during the period except when the magnetic head 11 is reading the magnetic information recorded on the magnetic stripe is reduced, and the reading performance of the magnetic recording medium in the environment where the magnetic noise is generated is improved. Is possible.
Therefore, the magnetic card reader 10 determines the gain of the differential amplifier circuit 12 as the first gain while recognizing the position of the magnetic card MC in the card transport path 14 detected by each detection sensor of the detection sensor group 17. The second gain G2 is controlled to be lower than G1 or the first gain G1.

  The detection sensor group 17 includes a prehead (PH), a switch (SW), a plurality of photosensors (photosensors) (PD1 to PD5) arranged along the card transport path 14, as will be described later in association with the mechanism. It is comprised including.

  The control unit 18 recognizes the presence and position of the magnetic card MC in the card transport path 14 detected by each detection sensor of the detection sensor group 17, and sets the gain of the differential amplifier circuit 12 to the first gain G1 or the first gain. The second gain G2 is controlled to be lower than G1.

When the magnetic card MC is outside the reading range, the control unit 18 performs control so that the gain of the differential amplifier circuit 12 is decreased until the magnetic card MC is within the reading range.
In this embodiment, a value that is not easily affected by magnetic noise, that is, a signal that is output from the magnetic head (here, magnetic noise) cannot be recognized as a magnetic analog signal, or is output from the magnetic head. The second gain G2 is set to a level at which the magnetic analog signal cannot be processed by the magnetic information reading unit.
Specifically, the control unit 18 controls the gain of the differential amplifier circuit 12 to a second gain G2 that is lower than the first gain G1 that can maintain a signal level that allows signal processing when the gain is outside the reading range. .
More specifically, the control unit 18 controls the gain of the differential amplifier circuit 12 to the second gain G2 until the magnetic card MC reaches the reading range, and controls to the first gain G1 while passing through the reading range. Then, after passing through the reading range, the second gain G2 is controlled.
In other words, the control unit 18 sets the gain of the differential amplifier circuit 12 to the first level at which the amplified signal can be processed normally when the magnetic card MC is within the reading range of the magnetic information of the magnetic head 11. When it is outside the reading range, control is performed so that the second level is lower than the first level.
Thus, since the magnetic card reader 10 reduces the second gain G2 (value thereof) by the first gain G1, even when magnetic noise is detected by the magnetic head 11, the output magnetic analog signal is magnetic. Even if the information is input to the information reading unit 13, the output value is small, so that it cannot be processed in the magnetic information reading unit 13. As a result, magnetic noise is not erroneously processed as a magnetic analog signal, so that it is less susceptible to magnetic noise.

As will be described later, in the present embodiment, the control unit 18 is generally configured such that the photosensors PD3 and PD4 are arranged in the vicinity of the magnetic head 11, and these photosensors are turned on (ON) or off (OFF). ) To determine whether it is within the reading range or outside the reading range.
More specifically, the control unit 18 determines whether the detection signal DT of the photosensor is at a high level indicating ON or at a low level indicating OFF, and is within the reading range or outside the reading range. to decide.

  Note that the control unit 18 can also be configured to have a function of reading and recognizing magnetic card information based on output data of the demodulation circuit 132 of the magnetic information reading unit 13.

The magnetic card reader 10 is connected to a host device (not shown) via an interface circuit 19 and a communication line (not shown), and transmits demodulated data to the host device, for example.
As the interface circuit 19, in order to establish communication between the host device and the magnetic card reader 10, various communication methods such as the RS232C method, the parallel port method, and the USB (Universal Serial Bus) connection method are adopted.

The outline of the configuration and functions of the signal processing system and the drive system for adjusting the gain of the amplifier circuit in the magnetic card reader 10 according to the present embodiment has been described above.
Next, a specific structure such as a magnetic card transport system of the magnetic card reader will be described with reference to FIG.

[Magnetic card reader structure]
As described above, FIG. 3 is a plan sectional view schematically showing the structure of the magnetic card reader 10 according to the embodiment of the present invention. Specifically, it is a diagram showing the arrangement of magnetic heads and detection sensor groups in the block diagram of the magnetic card reader shown in FIG.

In FIG. 3, the magnetic card reader 10 according to the embodiment of the present invention has a card insertion slot 20 for taking the magnetic card MC to be inserted into the magnetic card reader 10 into the card transport path 14.
The magnetic card reader 10 includes a pre-head (PH) 171 that transmits a signal that triggers driving of the drive motor 16, a lever 172 that protrudes from the card transport path side plate 141 into the card transport path 14, and a lever 172 machine. A micro switch (SW) 173 for detecting a typical movement.
The magnetic card reader 10 is a photo arranged to face a photodiode (not shown) for the purpose of confirming the position of the magnetic card MC in the card transport path 14 and detecting the length of the magnetic card MC. Sensors 174 to 178 (PD1 to PD5) are included.
These pre-head 171, lever 172, microswitch 173, and photosensors 174 to 178 form a detection sensor group 17.
The magnetic card reader 10 records and reproduces magnetic information to and from the magnetic card MC near the arrangement position of the photosensors 176 (PD3) and 177 (PD4) in the central portion of the card conveyance path 14 in the longitudinal direction. A magnetic head 11 is arranged.
In the magnetic card reader 10, the drive motor 16 is paired with the transmission belts 151 a and 151 b and the follower rollers 153 a to 153 c forming the card transport unit 15 and rotationally drives the drive rollers 153 d to 53 f via the drive shaft. In addition, various mechanical parts and electric parts (not shown) are arranged and arranged (in the broken line frame in FIG. 3).

The pre-head (PH) 171 detects the presence or absence of magnetic information recorded in the magnetic stripe mp and detects that the magnetic card MC has been inserted.
When the magnetic card MC inserted from the card insertion slot 20 is taken in, the pre-head 171 detects the fact and transmits a signal that triggers driving the drive motor 16 to the control unit 18.
Then, the control unit 18 that has received this signal transmits a drive signal to the drive motor 16, whereby the inserted magnetic card MC is drawn (conveyed).
Thereafter, the inserted magnetic card MC is driven to the back of the card transport path 14 (rightward in FIG. 3) by the drive rollers 153d to 153f forming the card transport unit 15 and the driven rollers 153a, 153b, 153c paired with the drive rollers. ).

The lever 172 and the micro switch 173 are an example of a “magnetic card position detection sensor” that detects the position of the inserted magnetic card MC, and function as a card insertion detection switch. The lever 172 and the micro switch 173 detect the width of the magnetic card MC.
In general, as shown in FIG. 3 and the like, in the magnetic card reader, in order to accurately read and write the magnetic stripe mp of the magnetic card MC and the magnetic head 11, the inserted magnetic card MC is inserted by a biasing member (not shown). The card is conveyed while being urged to the reference side on the card conveyance path 14 (the side opposite to the position where the magnetic head is disposed).
Because of the above configuration, the lever 172 and the micro switch 173 as the card detection switch are installed on the side opposite to the reference side. The lever 172 and the micro switch 173 have a structure that turns on when the magnetic card MC to be inserted is pressed in the lateral direction and turns off when the magnetic card MC is separated from the lever, and thus has a function of urging the magnetic card MC to the reference side. Have.
Further, since the lever 172 and the micro switch 173 as the card detection switch are installed on the side opposite to the reference side, for example, both the pre-head 171 and the lever 172 and the micro switch 173 as the card detection switch operate. When it is detected that the magnetic card MC has been inserted, it is determined that the inserted magnetic card MC is a card having a predetermined width or more, and the setting is made so that the card is taken into the magnetic card reader (by operating the shutter). be able to.
The lever 172 is mechanically installed on the card conveying surface, and the insertion of the magnetic card MC is detected by the lever 172 being pushed.
As described above, the pre-head 171 and the lever 172 and the micro switch 173 as the card detection switch are installed for the insertion, entry and mischief prevention of dust and foreign matters other than the magnetic card into the card transport path 14.

When the magnetic card MC inserted from the card insertion slot 20 is taken in, the lever 172 partially protruding into the card transport path 14 comes into contact with the inserted magnetic card MC, and the lever 172 moves downward in FIG. In response to the displacement, the microswitch 173 detects the mechanical movement of the lever 172.
Then, the microswitch 173 transmits a detection signal indicating that the mechanical movement of the lever 172 has been detected to the control unit 18, and based on this detection signal, the control unit 18 detects the magnetic card MC inserted. Detect (recognize) existence.
The lever 172 and the micro switch 173 can also detect the length of the inserted magnetic card.

The photosensors 174 to 178 (PD1 to PD5) are optical sensors each composed of a combination of a light emitting element and a light receiving element, and in this embodiment, a space between the light emitting element and the light receiving element (that is, the card transport path 14). When the magnetic card MC passes, the light from the light emitting element is blocked by the magnetic stripe mp formed on the surface thereof, so that the presence of the magnetic card can be detected.
As the photosensors 174 to 178, a magnetic sensor or an ultrasonic sensor can be considered. However, since the sensitivity of the former is easily influenced by the surrounding magnetic environment, the sensitivity of the latter is easily influenced by the ambient temperature and humidity. Therefore, it is preferable to use an optical sensor that does not depend on these.
An infrared sensor may be used as the detection sensor. The photosensors 174 to 178 function as an example of a “magnetic card position detection sensor” that detects the position of the inserted magnetic card MC.
Further, only the photosensors 174 to 178 may be an example of the “magnetic card position detection sensor”.

As described above, the magnetic card reader 10 is configured to transport the magnetic card MC in the card transport path 14 by the drive rollers 153d to 153f and the driven rollers 153a to 153c that are rotationally driven by the drive motor 16.
Such a magnetic card reader 10 includes, for example, a first measurement function unit for obtaining a temporary card length of the magnetic card MC, a second measurement function unit for obtaining a slip amount of the driving roller, and a temporary measurement performed by the first measurement function unit. An arithmetic function unit that subtracts the slip amount measured by the second measurement function unit from the card length to obtain the true card length of the magnetic card MC. The arithmetic function unit is configured by the control unit 18.
The card length refers to the length of the side along the conveyance direction of the magnetic card MC.

The first measurement function unit includes a photosensor 176 (PD3), a photosensor 177 (PD4), and a control unit 18, and the magnetic card MC based on the detection results of the photosensor 176 (PD3) and the photosensor 177 (PD4). Find the temporary card length.
In the first continuation function unit, the photosensor PD4 arranged on the downstream side in the card conveying direction detects the leading edge MCa of the magnetic card MC, and the photosensor PD3 arranged on the upstream side in the conveying direction is the trailing edge MCb of the magnetic card MC. Is detected.
The second measurement function unit includes a photosensor 177 (PD4), a photosensor 178 (PD5), and a control unit 18, and based on the detection results of the photosensor 177 (PD4) and the photosensor 178 (PD5), Find the slip amount.
The second measurement function unit detects either the front end MCa or the rear end MCb of the magnetic card MC by the two photosensors PD4 and PD5.
In the present embodiment, the photo sensor disposed on the downstream side in the transport direction of the first measurement function unit and the photo sensor disposed on the upstream side in the transport direction of the second measurement function unit are shared.

In the present embodiment, the interval between the photosensor PD3 and the photosensor PD4 is configured to be shorter than the card length of the magnetic card MC.
In the present embodiment, the distance between the photosensor PD3 and the photosensor PD5 is also shorter than the card length of the magnetic card MC.
However, the distance between the photosensor PD3 and the photosensor PD5 may be the same as or longer than the card length of the magnetic card MC. The pre-head 171 and the photosensors PD1 to PD5 as insertion detection sensors are arranged so as to detect the position of the magnetic card MC inserted into the magnetic card reader 10 and not to lose sight of the position of the conveyed magnetic card MC. .

The magnetic head 11 includes at least a pair of magnetic cores arranged to face each other with a magnetic gap (gap spacer) interposed therebetween. One magnetic core has a reproducing coil and the other magnetic core is wound with a recording coil. The head moves in contact with the card that has been slid.
Thereby, the magnetic head 11 can read (reproduce) magnetic information stored in the inserted magnetic card MC, and write (record) new magnetic information on the inserted magnetic card MC. It becomes.

In FIG. 3, drive rollers 153d to 153f that are driven to rotate by the drive motor 16 are paired with driven rollers 153a to 153c in order to sandwich the inserted magnetic card.
That is, the driven rollers 153a to 153c are urged toward the drive rollers 153d to 153f, respectively.
Specifically, each of the driven rollers 153a to 153c is urged toward the drive rollers 153d to 153f from the upper side of the card transport path 14 so as to be able to contact the upper surface of the inserted magnetic card. ing.

Here, in general, the magnetic information read and written by the magnetic head 11 described above is recorded in a magnetic stripe mp printed on the surface of the magnetic card MC to be inserted. The magnetic stripe mp and the magnetic head 11 face each other.
In the magnetic card reader 10 according to the present embodiment, as shown in FIG. 3, the photosensors 174, 175, and 178 are arranged on a straight line with the magnetic head 11 in the card transport direction.
Therefore, the photosensors 174, 175, and 178 are arranged at positions where the magnetic stripe mp passes in the card transport path 14.
Thereby, for example, even when a non-standard transparent card is inserted into the magnetic card reader 10, since the magnetic stripe is formed on the surface thereof, the photosensors 174, 175, and 178 detect the magnetic stripe. Thus, the position of the magnetic card MC can be detected.
Furthermore, even if the magnetic card MC is a non-standard transparent card, even if the magnetic card MC is inserted into the magnetic card reader 10, the sensor can detect the magnetic stripe, and the position of the magnetic card MC Can be accurately detected.

Among the lever 172 and the photosensors 174 to 178 cited as the “magnetic card position detection sensor”, the photosensors 174 and 175 are located on the side of the card insertion slot 20 into which the magnetic card is inserted using the position of the magnetic head 11 as a reference. Has been placed.
On the other hand, the photosensor 178 is arranged on the downstream side of the magnetic head 11 in the transport direction (right side in FIG. 3) with respect to the position of the magnetic head 11.
In the present embodiment, by arranging the magnetic card position detection sensor, it is possible to reliably detect the position where the magnetic card MC slides while contacting the magnetic head 11. When the magnetic card MC is in contact with the magnetic head 11 and slides, it can be determined that the magnetic analog signal output from the magnetic head 11 is a legitimate magnetic signal, and conversely, the magnetic card MC is magnetic. If it is not in the vicinity of the head 11, it can be determined that it is magnetic noise. As a result, the magnetic card reader 10 is less susceptible to magnetic noise and can reliably suppress reading errors caused by the magnetic head 11.

In the magnetic card reader 10 according to the present embodiment having the above-described configuration, first, as a premise, magnetic information is reproduced or recorded by the magnetic head 11 in the magnetic stripe mp on the magnetic card MC inserted from the card insertion slot 20.
The magnetic card reader 10 conveys the magnetic card MC inserted using the drive rollers 153d to 153f driven by the drive motor 16 in the card conveyance path 14, and a plurality of photosensors provided in the card conveyance path 14 Based on the detection signals from 174 to 178, the controller 18 detects the position of the magnetic card MC inserted and controls the conveyance.
At this time, in the magnetic card reader 10 of the present embodiment, the magnetic card reader 10 is less susceptible to magnetic noise and suppresses reading errors caused by the magnetic head. In other words, the magnetic noise during the period except when the magnetic head 11 is reading the magnetic information recorded on the magnetic stripe is reduced, and the magnetic card MC that is a magnetic recording medium in the environment where the magnetic noise is generated is read. The following processing is performed to improve the performance.
That is, while the control unit 18 recognizes the position of the magnetic card MC in the card transport path 14 detected by each detection sensor of the detection sensor group 17, the gain of the differential amplifier circuit 12 is set to the first gain G1 or the first gain G1. Control to a lower second gain G2.
Only when magnetic information is actually read from the magnetic card MC by the magnetic head 11, amplification is performed with the normal first gain G1.
When the magnetic head 11 does not actually read the magnetic information from the magnetic card MC, the gain of the differential amplifier circuit 12 is changed from the first gain G1 to the first gain G1 so that the amplified data does not make sense as processed data. Decrease to 2 gain G2.
This control is also performed by the control unit 18 according to the detection result of each sensor of the detection sensor group 17.

In the present embodiment, the photosensors 174 to 178 include photosensors 174, 175, and 178 disposed at positions where the magnetic stripe mp of the magnetic card MC passes, and photosensors 176 and 177 disposed in the vicinity of the magnetic head 11. And is composed of.
In the present embodiment, for example, using the detection signal of either the magnetic head 11 or the photosensors 176 and 177 arranged in the vicinity of the magnetic head 11, it is determined that the inserted magnetic card is a normal magnetic card. It is also possible to make a determination and continue the processing.
In this case, when it is determined that the inserted magnetic card is a normal magnetic card, the magnetic card reader 10 brings the magnetic head 11 into contact with and slides on the magnetic stripe mp on the surface of the inserted card. The magnetic data stored in the magnetic card is read or new magnetic data is written to the card.

[Timing when detection signal of each sensor is turned on and actual movement of magnetic card]
Next, the timing when the detection signal of each sensor of the detection sensor group according to the present embodiment is turned ON and the state in which the magnetic card actually moves in the card transport path 14 will be described with reference to FIGS. .

  4 to 8 are diagrams showing how the magnetic card actually moves along the card transport path.

First, consider a case where a normal magnetic card MC is inserted as shown in FIG.
When the pre-head 171, the lever 172 as a card detection switch and the micro switch 173 detect that the magnetic card has been inserted into the insertion slot 20, the magnetic card MC is taken into the magnetic card reader 10 (Backward direction: FIG. 4) (toward the right side of 4), the drive motor 16 starts to drive the drive roller, and is further conveyed as shown in FIG. 5, and the detection signals DT1 and DT2 of the photosensors PD1 and PD2 are ON (high level in the figure). Thus, the presence of the inserted magnetic card MC is detected.
In this case, assuming that the magnetic card MC is out of the reading range, the control unit 18 controls the gain of the differential amplifier circuit 12 to be lowered from the normal first gain G1 to the second gain G2 lower than the normal first gain G1.

As shown in FIG. 5, when the tip MCa of the magnetic card MC passes the photosensor PD3, the detection signal DT3 of the photosensor PD3 in the vicinity of the magnetic head 11 is turned on (for example, high level), and the position of the photosensor PD3 is changed. Assuming that the magnetic card MC is within the reading range from the position (position) determined to have passed, the control unit 18 increases the gain of the differential amplifier circuit 12 from a low second gain G2 to a higher first gain G1. To be controlled.
Then, as shown in FIGS. 6 and 7, the magnetic head 11 starts taking in (reading) the magnetic signal, and the magnetic card inserted at the position of the photosensor PD4 and further the photosensor PD5 arrives and reaches the specified value. After running for a minute, the acquisition and conveyance of magnetic information is completed.
Thus, the passage of the magnetic card MC inserted in the photosensors PD3 and PD4 can be detected.
As described above, while the detection signals DT3 and DT4 of the photosensors PD3 and PD4 are ON (high level in the figure), the control unit 18 changes the gain of the differential amplifier circuit 12 from the low second gain G2 to the first higher than that. Control is performed to increase (return) the gain G1.
Then, as shown in FIG. 8, when the detection signal of the photo sensor PD3 is turned off (low level), or when the detection signal of the photo sensor PD4 is turned off after a predetermined period, the magnetic card MC has moved out of the reading range. As a result, the control unit 18 controls the gain of the differential amplifier circuit 12 to be lowered from the first gain G1 to the second gain G2 lower than the first gain G1.

  In general, the card length of the inserted magnetic card is calculated using the lever 172, the photosensors PD3 and PD4, and the card conveyance amount. For example, the lever 172 (switch SW1) and the magnetic head 11 are calculated. The card length of the card may be calculated using the fact that the card has reached the head portion of the magnetic head 11 and the amount of card transport based on the magnetic signal from.

  Next, a correspondence relationship between each detection signal and gain control of the differential amplifier circuit 12 when the inserted magnetic card MC is detected by each sensor will be described with reference to FIGS.

In order, the lever 172 (hereinafter referred to as switch SW1) is turned on at the first timing shown in FIG. 4, and the photosensor PD1 corresponding to the photosensor 174 is turned on at the predetermined second timing in FIG. At a third timing, the photosensor PD2 corresponding to the photosensor 175 is turned on.
The switch SW1 is turned off at the fourth timing, the photosensor PD3 corresponding to the photosensor 176 is turned on at the fifth timing, and the PD4 corresponding to the photosensor 177 is turned on at the sixth timing shown in FIG.
The photosensor PD1 is turned off at the predetermined seventh timing in FIG. 6, the photosensor PD2 is turned off at the eighth timing, and the PD5 corresponding to the photosensor 178 is turned on at the ninth timing in FIG.
Then, the photosensor PD3 is turned off at the tenth timing in FIG. 8, and the photosensor PD4 is turned off at the eleventh timing.

Here, in FIGS. 5, 6, and 7, it is a period in which one or both of the photosensors PD <b> 3 and PD <b> 4 in the vicinity of the magnetic head 11 is ON.
For example, during a predetermined period selected including this period, the gain of the differential amplifier circuit 12 is increased from the second gain G2 lower than normal to the normal first gain G1 by the control unit 18 assuming that it is within the reading range. To be controlled.
During the other period, the control unit 18 controls the gain of the differential amplifier circuit 12 to be lowered from the normal first gain G1 to the second gain G2 lower than that, assuming that the period is outside the reading range.

Note that the period within the reading range is not necessarily the period shown in FIGS. 5 to 7, and it is possible to select a period during which magnetic information can be reliably read.
For example, assuming that the period shown in FIGS. 5 to 8, the period shown in FIGS. 6 to 8, etc. are also within the reading range, the control unit 18 sets the gain of the differential amplifier circuit 12 from the second gain G <b> 2 lower than normal. It is also possible to configure such that control is performed to return (increase) the first gain G1.

  The gain control of the differential amplifier circuit 12 has been described with respect to an example in which the magnetic card MC is conveyed in the right direction (forward direction) in FIGS. 4 to 8, but the magnetic card MC in the left direction (reverse direction). The same control can be performed when transporting.

[Operation of card transport by magnetic card reader]
Next, the operation of the magnetic card reader 10 according to the present embodiment will be described focusing on the gain control of the differential amplifier circuit 12 related to the detection signal of each sensor accompanying card conveyance.

FIG. 9 and FIG. 10 are flowcharts for explaining the gain control of the differential amplifier circuit related to the detection signal of each sensor accompanying card conveyance in the magnetic card reader according to the present embodiment.
Here, the period within the reading range is a period in which either or both of the photosensors PD3 and PD4 in the vicinity of the magnetic head 11 are ON.

First, the control unit 18 of the magnetic card reader 10 determines whether or not the switch SW1 (lever 172) is turned on in order to determine whether or not the customer's magnetic card MC has been inserted (step ST11).
When the switch SW1 (lever 172) is turned from OFF to ON (step ST11: Yes, see FIG. 4), the drive motor 16 is driven and controlled by the control unit 18 as a trigger (trigger), and the transport roller (drive roller) Driving of 153d to 153f is started (step ST12).
At the start of driving, the control unit 18 is assumed to be outside the reading range, and is controlled by the control unit 18 to lower the gain of the differential amplifier circuit 12 from the normal first gain G1 to the second gain G2 lower than that. (Step ST13).
When the magnetic card MC is further inserted into the back of the magnetic card reader 10 and the photo sensor PD1 is turned on (step ST14: Yes), the card conveyance starts, and the control unit 18 sets a timer TM1 (not shown) to 2 for example. Seconds are set (step ST15).

  When the card conveyance is started, the conveyance distance of the inserted magnetic card can be calculated from the number of encoder pulses engraved by the rotation of the conveyance rollers (drive rollers) 153d to 153f. In terms of mechanism, the distances from the switch SW1 (lever 172) to the photosensor PD1, the photosensors PD1 to PD3, and the photosensors PD3 to PD5 are known.

Note that the gain control in step ST13 may be configured to be performed after detecting that the photosensor PD1 is turned on in step ST14.
In this embodiment, in order to reduce the influence of magnetic noise as much as possible, the motor is driven and the control unit 18 lowers the gain of the differential amplifier circuit 12 from the normal first gain G1 to a lower second gain G2. To be controlled.

Here, if it is detected that the photosensor PD2 is turned on (step ST16: Yes), the photosensor PD3 on the upstream side of the card conveyance path disposed in the vicinity of the magnetic head 11 is next detected in the control unit 18. It is determined whether or not it is turned on (step ST17).
If it is not determined in step ST17 that the photosensor PD3 has been turned on, the determination process is performed until the timer TM1 becomes 0 (step ST18: No).
If it is not determined in step ST17 that the photosensor PD3 is turned on and the timer TM1 set in step ST15 (for example, 2 seconds) is 0 (step S18: Yes), a jam (JAM) occurs. As a result (step ST19), the capturing operation is terminated.

Various processes can be considered for the process after the capture operation is completed through step ST19.
For example, the magnetic card may be forcibly ejected, or the magnetic card may be left in the magnetic card reader 10 until the service person arrives, or may be taken into the host device through the magnetic card reader 10. Good.

In step ST17, when the control unit 18 determines that the photosensor PD3 is in the ON state, the process proceeds to step ST20 in FIG.
In step ST20, assuming that the signal has reached the reading range, the control unit 18 increases (returns) the gain of the differential amplifier circuit 12 from the second gain G2 lower than normal to the normal first gain G1 higher than that. To be controlled).

Next, a timer TM2 (not shown) is set by the control unit 18 (step ST21).
Then, until the timer TM2 becomes 0 (step ST24), the photosensor PD4 is turned on (see step ST22, FIG. 5), and it is further determined whether or not the photosensor PD5 is turned on. (See step ST23, FIG. 6).
When the photosensor PD5 is not turned on (step ST23: No, and step ST24: Yes), it is assumed that a phenomenon (so-called JAM) that does not move near the center in the apparatus occurs (step ST25). , End the capture operation.
The processing after the capture operation is completed is the same as described above.

On the other hand, when the photosensor PD5 is turned on before the timer TM2 becomes 0 (step ST23: Yes), the photosensor PD3 disposed in the vicinity of the magnetic head 11 is then turned off. Is determined (step ST26).
If it is determined in step ST26 that the photosensor PD3 has been turned off (step ST26: Yes), the control unit 18 determines that it has passed through the readable range, and the control unit 18 performs differential operation. Control is performed so that the gain of the amplifier circuit 12 is lowered from the first gain G1 to the second gain G2 lower than the first gain G1 (step ST27).

Next, the transport distance is set (step ST28), and the inserted magnetic card MC is moved by a predetermined distance.
Then, when the magnetic card MC is transported for a predetermined distance (step ST29: Yes), the drive motor 16 is stopped (step ST30) and the card taking is finished (step ST31), assuming that the card transport is finished.

  In FIGS. 9 and 10, the above-described conveyance and gain control can be performed using three photosensors PD1 or PD2, PD3, and PD5.

[Effect of the embodiment]
As described above, in the card reader 10 of the present embodiment, the magnetic noise during a period other than during reading by the magnetic head 11 is reduced, and the reading performance of the magnetic card MC that is a magnetic recording medium in an environment where magnetic noise is generated. The following processing is performed in order to improve.
That is, while the control unit 18 recognizes the position of the magnetic card MC in the card transport path 14 detected by each detection sensor of the detection sensor group 17, the gain of the differential amplifier circuit 12 is set to the first gain G1 or the first gain G1. Control to a lower second gain G2.
Only when magnetic information is actually read from the magnetic card MC by the magnetic head 11, amplification is performed with the first gain.
When the magnetic information is not actually read from the magnetic card MC by the magnetic head 11, the gain of the differential amplifier circuit 12 is changed from the first gain G1 so that the gain does not make sense as processed data even if amplified. Lower to the second gain G2.
This control is performed by the control unit 18 according to the detection result of each sensor of the detection sensor group 17.
When the card reader 10 is out of the reading range, the magnetic signal output from the magnetic head 11 is processed with the second gain G2, so that the card reader 10 is less susceptible to magnetic noise and more reliably suppresses reading errors caused by the magnetic head 11. can do.

Therefore, according to the present embodiment, the following effects can be obtained.
The magnetic card reader according to the present embodiment can reduce magnetic noise during a period other than during reading by the magnetic head, and can greatly reduce the influence of external magnetic noise.
In this embodiment, motor noise can be reduced compared to mechanical motor noise countermeasures such as a magnetic shield, as well as noise during card transport other than reading by a magnetic head can be reduced. Can sufficiently improve the reading performance.
That is, according to the present embodiment, it is possible to reduce magnetic noise during a period other than during reading by the magnetic head, and it is possible to improve the reading performance of the magnetic recording medium in an environment where magnetic noise occurs.

[Other Embodiments]
In the present application, since the second gain (value) is lowered, even if the magnetic noise is detected by the magnetic head, the output value is small even if the output magnetic signal is input to the magnetic information reading unit. Cannot be processed in the magnetic information reader.
For example, even when the magnetic noise is large and the magnetic gain is lowered to the second gain, it is conceivable that the magnetic signal output from the magnetic head can be processed as it is by the magnetic information reading unit. When the second gain is used, the magnetic signal output from the magnetic head is determined not to be a legitimate magnetic signal, and the magnetic information reading unit may perform processing so as not to demodulate.
Further, in a state where the second gain is selected by the switching unit, even if magnetic noise enters the magnetic head, it is out of the reading range, so that it is not determined as a read signal at the magnetic head, and demodulation processing is performed. By not doing so, it is possible to provide a magnetic card reader that is less susceptible to magnetic noise.

In the embodiment described above, a motor type magnetic card reader having a drive motor has been described as an example. However, the present invention is not limited to a manual type magnetic card reader without a motor. This is effective when there is a device that generates electrical noise such as equipment.
Normally, in the case of a manual magnetic card reader, since a sensor for detecting the card position is not arranged, the initial gain before reading the magnetic card is set low, and a specific pattern (0 of the magnetic information (magnetic signal) head) is set. The gain may be increased when it is detected that the continuation continues for several bits, and the gain may be decreased when the data pattern of the end of the magnetic information is detected.

  The magnetic stripe mp formed on the magnetic card MC includes information indicating the start (start) and end (end) of magnetic information.

[Start code judgment processing]
FIG. 11 is a conceptual diagram showing an example of a recording format of one block (one row) of magnetic information of the magnetic stripe mp.
FIG. 12 is a diagram illustrating each code and a waveform level pattern corresponding to the code.

In the recording format of FIG. 11, PR indicates a preamble and is composed of at least 10 “0” data.
SS indicates a start code which is information indicating the start (start), and hexadecimal 0BH is assigned thereto, and its waveform level pattern 11110110 is recorded.
DT indicates data, and transaction information and other data are recorded.
ES indicates an end code which is information indicating end (end).
Subsequently, LRC indicates a check code, and PS indicates a postamble.

In this case, the control unit 18 starts searching for the start code SS after finding, for example, 10 consecutive 0 data, that is, after confirming the preamble PR, based on the data from the demodulation circuit 132. The search for the start code SS is performed, for example, by collating with the waveform level pattern shown in FIG.
Basically, when the start code SS is detected, the control unit 18 controls the gain of the differential amplifier circuit 12 to an appropriate (normal) first gain G1.
Then, the control unit 18 searches for the end code ES. When the end code ES is detected, the control unit 18 performs control to reduce the gain of the differential amplifier circuit 12 to an appropriate first gain to the second gain G2.
More specifically, the control unit 18 controls the gain of the differential amplifier circuit 12 to the second gain G2 before the start code SS is detected, and the first gain G1 when the start code SS is detected. When the end code ES is detected, the second gain G2 is controlled.

  Also in such an embodiment, the same effect as that of the above-described embodiment can be obtained.

In another embodiment, the card detection sensitivity (threshold value) may be changed instead of changing the gain.
That is, the sensitivity is lowered before the head passes, the sensitivity is increased while the head passes, and the sensitivity is lowered after the head passes.

In this case, the control unit 18 fixes the gain of the differential amplifier circuit (amplifier unit) 12 to the first gain G1, and when the magnetic card MC is outside the reading range of the magnetic information of the magnetic head 11, the magnetic unit MC The detection sensitivity of the card MC is controlled to a second sensitivity lower than the first sensitivity when the card MC is within the reading range.
More specifically, the control unit 18 controls the sensitivity of the differential amplifier circuit 12 to the second sensitivity until the magnetic card MC reaches the reading range, and controls the sensitivity to the first sensitivity while passing through the range. After passing the range, the second sensitivity is controlled.
In other words, the control unit 18 fixes the gain of the differential amplifier circuit 12 to the first gain G1, and when the magnetic card MC is outside the region passing the arrangement position of the magnetic head 11, the transport path is set. The detection sensitivity, which is a level for detecting the magnetic card MC being conveyed, is controlled to a second sensitivity that is lower than the first sensitivity when the magnetic card is in a region passing through the position where the magnetic head 11 is disposed.

  According to this example, this makes it difficult for the magnetic card MC to be detected and recognized at an incorrect position or timing when the magnetic card MC is outside the reading range of the magnetic head 11. As a result, the drive motor, the magnetic head, and the like are driven with high precision and accuracy other than when the magnetic head 11 is in an area that passes through the position where the magnetic head 11 is disposed. Errors can be suppressed.

When the sensitivity can be changed at the threshold level, the control unit 18 controls as follows.
The controller 18 controls the first threshold when the first sensitivity is set, and controls the second threshold higher than the first threshold when the second sensitivity is set.

  Even in such a configuration, it is possible to obtain the same effect as that of the above-described embodiment.

  Each embodiment described above can be applied to other magnetic cards.

  DESCRIPTION OF SYMBOLS 10 ... Magnetic card reader (magnetic information processing apparatus), 11 ... Magnetic head, 12 ... Differential amplification circuit (amplification part), 13 ... Magnetic information reading part, 131 ... Peak detection circuit , 132 ... demodulation circuit, 14 ... card transport path, 15 ... card transport section, 16 ... drive motor, 17 ... detection sensor group, 18 ... control section, 181 ... Switching unit, 19 ... interface circuit, 20 ... card insertion slot, G1 ... first gain, G2 ... second gain, MC ... magnetic card (magnetic recording medium), mp ... Magnetic stripe.

Claims (1)

A magnetic head for reading magnetic information recorded on a magnetic recording medium;
An amplification unit capable of different gain amplification of the magnetic signal detected by the magnetic head;
A magnetic information reading unit that reads and demodulates magnetic information recorded on the magnetic recording medium from a magnetic signal detected by the magnetic head output from the amplification unit;
A switching unit that switches the gain of the amplifying unit between a reading range in which the magnetic head reads the magnetic information recorded on the magnetic recording medium and outside the reading range;
A transport path in which the magnetic head is disposed and the magnetic recording medium is transported;
A detection sensor for detecting the presence and position of the magnetic recording medium in the transport path;
A control unit capable of controlling the conveyance of the magnetic recording medium according to the detection result of the detection sensor, and capable of controlling the sensitivity that is a level at which the detection sensor detects that the magnetic recording medium has been detected. ,
The amplification unit is
A first gain capable of demodulating the magnetic information when the magnetic head is within a reading range for reading the magnetic information recorded on the magnetic recording medium;
A second gain outside a reading range for reading the magnetic information recorded on the magnetic recording medium by the magnetic head,
The second gain is
The gain is a level at which the magnetic signal output from the magnetic head cannot be processed by the magnetic information reading unit,
The controller is
The gain of the amplifying unit is fixed to the first gain, and when the magnetic recording medium is outside the magnetic information reading range of the magnetic head, it is a level for detecting the magnetic recording medium conveyed on the conveyance path. A magnetic information processing apparatus, wherein the detection sensitivity is controlled to a second sensitivity lower than the first sensitivity when the magnetic recording medium is within the reading range of the magnetic head.

Images