JPS63221494A - Magnetic card reader - Google Patents

Abstract

PURPOSE:To prevent an unauthorized use by adding a weak magnetic field before recording information is read. CONSTITUTION:At the core 24 of a magnetic head 20, a coil 26 for reading card recording information exists and the obtained detecting signal is sent through an amplifying circuit 28 to a differentiating circuit 30 for detecting a peak. For the differentiating signal of the circuit 30, the reading signal of card recording information is obtained through a demodulating circuit 32. For the amplifying signal of the circuit 28, a timer signal is supplied through a waveform shaping circuit 34 via a timer circuit 36 to a timer circuit 38. A bias coil 42 is conducted through a bias circuit 40 by the timer of the circuit 38. By the conducting, a weak magnetic field is added to a magnetic card. Thus, since the unfair information is erased by the weak magnetic field during the reading of the recording information, the unauthorized use can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a magnetic card reader that uses a magnetic head to read information recorded on a magnetic card.

(Summary of the Invention) In the present invention, a weak magnetic field is applied to the magnetic card before the information recorded in the high magnetic force layer of the card is read by a magnetic head.

(Background of the Invention) In a card such as a prepaid card in which the card itself has value because of magnetically recorded information, it is desired to prevent the recorded information from being erased by a magnet or the like.

For this reason, in the past, information was recorded on a magnetic layer of a magnetic card with high coercive force, and the recorded information was protected from external magnetic fields.

However, since it is possible to transfer recorded information from a high coercive force magnetic card to a low coercive force layer of another magnetic card, for example, recorded information can be magnetically copied from a prepaid card to a magnetic card used as a commuter pass. However, there was a problem that unauthorized use of this card could not be prevented.

(Object of the invention) The present invention has been made in view of the above-mentioned conventional problems, and
The purpose is to provide a magnetic card reader that can reliably prevent unauthorized use of magnetic cards due to magnetic copying of recorded information.

(Structure and Effects of the Invention) In order to achieve the above object, the present invention provides a magnetic card reader that uses a magnetic head to read information recorded on a high coercive force card, and that before the recorded information on the card is read by the magnetic head. The card is characterized in that a means for applying a weak magnetic field to the card is provided.

According to the present invention, since a weak magnetic field is applied to the magnetic card before the recorded information is read by the magnetic head, the recorded information by the magnetic copy of the fraudulent card is erased by the weak magnetic field, thus preventing unauthorized use of the card. It can definitely be prevented.

(Description of Embodiments) Hereinafter, preferred embodiments of the magnetic card reader according to the present invention will be described based on the drawings.

FIG. 1 shows the main structure of the first embodiment, and FIG. 2 shows its overall structure. In FIG. 2, the magnetic card 10 is inserted into the slot 12.

This magnetic card 10 has a coercive force of 2750 oersted and 105 bpi (maximum bit spacing is approximately 240A1m).
A high coercive force card (e.g. prepaid card) with FM recording of The magnetic card 10 inserted into the slot 12 is moved to the right end by the conveyor belt 16.degree. 18 of the card transport mechanism 14 and returned to the slot 12 again.

A magnetic head 20 is provided in the transport path of the magnetic card 10, and the recorded information on the magnetic card 10 is read by the magnetic head 20 when the magnetic card 10 is inserted.

Further, a magnetic head 22 is provided downstream of the magnetic head 20 in the transport path of the magnetic card 10.
When 0 is returned, the recorded information is rewritten by the magnetic head 22, and the recorded contents are checked by the magnetic head 20.

In FIG. 1, a coil 26 for reading card recorded information is wound around the core 24 of the magnetic head 20, and a detection signal obtained by the reading coil 26 is sent through an amplifier circuit 28 to a differential signal for peak detection. It is supplied to the circuit 30.

The differential signal from the differentiating circuit 30 is supplied to a demodulating circuit 32, and the demodulating circuit 32 obtains a reading signal for the card recorded information.

Further, the amplified signal of the amplifier circuit 28 is supplied to the timer circuit 36 via the waveform shaping circuit 34, and the timer signal of the timer circuit 36 is supplied to the timer circuit 38.

The timer signal of this timer circuit 38 is supplied to a bias circuit 40, which supplies the bias coil 4.
2 is energized.

The bias coil 42 is also wound around the core 24 of the magnetic head 20, and when the bias coil 42 is energized, a weak magnetic field is applied to the magnetic card 10.

Here, the maximum bit interval is about 240 μm and the information is FM.
When a recorded magnetic card 10e with high coercive force or a fraudulent one obtained by magnetically copying the magnetic card 10e is inserted into the slot 12, the magnetic card 10 is moved by the conveyor belt 16, 18 of the card conveyance mechanism 14 as shown in FIG. When the magnetic head 20 is transported to the right side, the reading coil 26 or the amplifier circuit 28 of the magnetic head 20 obtains a signal having the waveform shown in FIG. 3(A).

The signal has a period T1 as a half cycle, and the waveform shaping circuit 34 obtains a pulse signal with a period T1 shown in FIG. 3(B).

Furthermore, the timer 36 obtains a timer signal that rises at the first pulse input of the waveform shaping circuit 34 as shown in FIG. 3(C), and its time-up time T4 (see FIG. 4) is set longer than the period TI. There is.

Therefore, the timer signal of the timer circuit 36 remains raised as shown in FIG. 3(C).

The timer signal of the timer circuit 38 rises after the timer signal of the timer circuit 36 rises and when the timer circuit 38 times out after the period T2 has elapsed as shown in FIG. At 40, bias coil 42 is energized.

Therefore, a weak magnetic field is applied to the magnetic card 10 by the bias coil 42 from the magnetic head 20 while the magnetic card 10 is being read.

Therefore, if an unauthorized magnetic card 10 made by magnetic copying is inserted into the slot 12, the information is erased by a weak magnetic field while reading the recorded information, and as a result, unauthorized use of the magnetic card 10 is prevented. be done.

In addition, a regular magnetic card 1 as a commuter pass is inserted into the slot 12.
When 0 is inserted, a signal with a half period T3 shown in FIG. 4(A) is obtained by the reading coil 26 or the amplifier circuit 28, and the time-up time T4 of the timer circuit 36 shown in FIG. 4(C) is obtained. The waveform shaping circuit 34 outputs a waveform shaping pulse having a longer period.

Therefore, the timer circuit 38 does not time up, and therefore the bias coil 42 is not energized by the bias circuit 40, and as a result, the stored contents of the regular magnetic card 10, such as a commuter pass, are erased by the magnetic head 20. It can be read as is without any problem.

As explained above, according to this embodiment, the magnetic card 10
When the card is inserted into the slot 12, a weak magnetic field is applied from the magnetic head 20 to the magnetic card 10 while reading the recorded information, so that the recorded information of only the fraudulent magnetic card 10 due to magnetic copying is erased, and therefore it is not a legitimate magnetic card. Unauthorized use of the magnetic card 10 can be reliably prevented without erasing the recorded information on the magnetic card 10.

Further, according to this embodiment, a high coercive force card such as a prepaid card and a resistive magnetic force card such as a commuter pass are automatically distinguished, and a regular magnetic resistive force card 10 is inserted into the slot 10. If the magnetic head 2
Since a weak magnetic field is not applied from zero, erroneous erasure of the recorded information can be prevented, and therefore both high coercive force cards and resistive magnetic force cards can be handled with one magnetic card reader.

FIG. 5 shows the main configuration of the second embodiment, and in this embodiment, the signal from the demodulation circuit 32 is supplied to the control circuit 44.

The control circuit 44 performs the process shown in the flowchart of FIG. 6, and the bias circuit 40 is controlled by the control circuit 44.

In this way, the waveform shaping circuit 34 of the first embodiment. It is also possible to configure a magnetic card reader by replacing the timer circuits 36 and 38 with the control circuit 44.

FIG. 7 shows the overall configuration of a third embodiment, and in this embodiment, a magnetic head 46 is newly provided on the input port 12 side of the magnetic heads 20, 22.

The magnetic head 20 has a bias coil 42 shown in FIG.
The bias coil 42 is provided in the magnetic head 46.

Therefore, in this embodiment, before the high coercive force magnetic card 10 inserted into the slot 12 reaches the magnetic head 20,
It passes through a magnetic head 46, to which a weak magnetic field is applied in advance.

According to this embodiment, the reading coil 26 and the bias coil 4
Since the magnetic heads 20 and 2 are provided separately in the magnetic heads 20 and 46, fluctuations in the magnetic field due to noise in the bias coil 42 are not detected by the reading coil 26, and therefore, measures to prevent noise from entering the bias coil 42 are taken. There is no need to take it.

A fourth embodiment is shown in FIG. 8, in which a permanent magnet 48 and a solenoid 50 are used in place of the magnetic head 46 of FIG.

The permanent magnet 48 is driven forward and backward with respect to the transport path of the magnetic card 10 by a solenoid 50, and the permanent magnet 48 is driven close to the magnetic card 10 during transport.
8 gives a weak magnetic field.

According to this embodiment, since a strong magnetic field is not generated in the permanent magnet 48 as in the core cap of a magnetic head, the recorded information near the surface of the high coercive force card will not be erased.

As a result, the reading level of the high coercive force card does not decrease, and therefore it is no longer necessary to accurately determine the distance to the magnetic card 10 that applies a weak magnetic field, unlike in the case of a magnetic head, and the mechanism can be simplified. becomes.

[Brief explanation of the drawing]

Figure 1- is a block diagram showing the configuration of the main parts of the first embodiment, Figure 2 is a schematic diagram explaining the configuration of the first embodiment, and Figures 3 and 4 show the signals provided in each part of the first embodiment. A waveform diagram, FIG. 5 is a block diagram showing the main configuration of the second embodiment, FIG. 6 is a flowchart explaining the operation of the control circuit in the second embodiment, and FIG. 7 is a configuration explanation of the third embodiment. 8 are explanatory diagrams of the configuration of the fourth embodiment. 10...Magnetic card 14...Card transport mechanism 20...Magnetic head 26...Reading coil 28...Amplification circuit 34...Waveform shaping circuit 36.38...Timer circuit 40... Bias circuit 42...Bias coil 44...Control circuit 46...Magnetic head 48...Permanent magnet 50...Solenoid Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] (1) A magnetic card reader that uses a magnetic head to read information recorded on a high coercive force card is provided with means for applying a weak magnetic field to the card before the magnetic head reads the information recorded on the card. A magnetic card reader featuring: