JP2610863B2 - Magnetic card reader - Google Patents

Description

The present invention relates to a magnetic card reader for reading information recorded on a magnetic card with a magnetic head.

<< Summary of the Invention >> In the present invention, a weak magnetic field is applied to a magnetic card before the information recorded on the high magnetic layer is read by a magnetic head.

<< Background of the Invention >> In the case of a prepaid card, which is magnetically recorded information whose value itself is recognized, it is desired to prevent erasure of recorded information by a magnet or the like.

Therefore, conventionally, information is recorded on a magnetic layer of the magnetic card having a high coercive force, and the recorded information is protected from an external magnetic field.

However, since recorded information can be transferred from a magnetic card having a high coercive force to a low coercive force layer of another magnetic card, for example, the recorded information is magnetically copied from a prepaid card to a magnetic card used as a commuter pass. Thus, there is a problem that unauthorized use of this card cannot be prevented.

<< Object of the Invention >> The present invention has been made in view of the above-mentioned conventional problems, and has as its object to ensure that the magnetic information of a high coercive force card can be reliably obtained without adversely affecting the information recorded on a regular resistive magnetic force card. An object of the present invention is to provide a magnetic card reader capable of preventing unauthorized use by copying.

<< Structure and Effect of the Invention >> In order to achieve the above object, the present invention relates to a magnetic card reader for reading FM recorded information recorded on a magnetic card with a magnetic head, wherein the magnetic card reader is inserted based on a read signal from the magnetic head. Discriminating means for judging whether or not the repetition frequency of FM recording of the magnetic card is for recording a high coercive force card; and the repetition frequency of FM recording of the magnetic card inserted by the discriminating means has a high coercive force. If it is determined that the information is for card recording, a magnetic field for erasing low coercive force information is applied before the magnetic head reads the information on the magnetic card, and the FM recording on the magnetic card is repeated. A magnetic field applying unit that does not apply a magnetic field for erasing the low coercive force information when the frequency is determined to be for recording a low coercive force card. .

Thus, according to the present invention, the inserted magnetic card
If it is determined that the repetition frequency of the FM recording is for recording a high coercive force card, a magnetic field for erasing the low coercive force information is applied before the magnetic head completes reading the recorded information on the magnetic card. On the other hand, if the repetition frequency of FM recording of the magnetic card is determined to be for low coercivity card recording, the magnetic field for erasing the low coercivity information was not applied, so that illegal information was If it is recorded, the illegal information is erased, and the illegal use of the magnetic card on which the illegal information is recorded can be prevented.

<< Description of Embodiments >> Preferred embodiments of a magnetic card reader according to the present invention will be described below with reference to the drawings.

FIG. 1 shows the main structure of the first embodiment, and FIG. 2 shows the entire structure thereof. 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 105b
High coercivity card (for example, a prepaid card) with FM recording of pi (maximum bit interval of about 240 μm), or 300 oersted coercive force and minimum bit interval of 1.2 mn
A low coercivity card (for example, a commuter pass) recorded as NMZ1. The magnetic card 10 inserted into the slot 12 is moved to the right end by the conveyor belts 16 and 18 of the card transport mechanism 14 and returned to the slot 12 again. Is done.

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

A magnetic head 22 is provided on the downstream side of the magnetic head 20 in the transport path of the magnetic card 10, and when the magnetic card 10 is returned, the recording information is rewritten by the magnetic head 22, and the recorded contents are changed by the magnetic head. Checked by 20.

In FIG. 1, a coil 26 for reading card recording information is wound around a core 24 of the magnetic head 20, and a detection signal obtained by the reading coil 26 is passed through an amplification circuit 28 to a differential signal for peak detection. The circuit 30 is provided.

The differentiated signal of the differentiating circuit 30 is supplied to a demodulation circuit 32, and the demodulation circuit 32 obtains a read signal of card record information.

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.

Here, the waveform shaping circuit 34, the timer circuit 36, and the timer circuit 38 constitute a recording density judging means of the present invention, and the recording information of the inserted magnetic card 10
When read by 20, it is determined whether or not the recording density of the recording information of the inserted magnetic card is equal to or more than a specified value based on the read signal through the amplifier circuit 28, and when the recording density is equal to or more than the specified value. If it is determined, the inserted magnetic card can be said to be a high coercivity magnetic card or a magnetic card on which illegal information is recorded by magnetic copying.
Only in this case, a timer signal is supplied from the timer circuit 38 to the bias circuit 40, as described later, so that the bias circuit 40 energizes the bias coil 42 as the magnetic field applying means.

The bias coil 42 is wound around the core 24 of the magnetic head 20, and is energized by the bias circuit 40 so that the read coil 26 is illegally copied to the magnetic card 10 by magnetic copying before the reading of the magnetic information is completed. A weak magnetic field is applied to erase important information.

The low coercive force card such as a magnetic card type commuter pass and the high coercive force card such as a prepaid card are standardized not only in size but also in recording density of recording information. The card is classified into a low coercive force card and a high coercive force card according to the specified value of the density, so it is determined whether the card is a low coercive force card or a high coercive force card based on this specified value. Thus, the recording information is not erased to the resistive magnetic force card inserted by mistake without applying a weak magnetic field for erasing illegal information.

Next, a description will be given of a process in a case where a legitimate or illegal magnetic card is inserted into the magnetic card reader configured as described above.

First, when a regular magnetic card 10 having a high coercive force and information recorded by FM with a maximum bit interval of about 240 nm and an illegal one obtained by magnetic copying is inserted into the slot 12, the card transport mechanism 14 When the magnetic card 10 is transported to the right in FIG. 2 by the transport belts 16 and 18, the read coil 26 or the amplifier circuit 28 of the magnetic head 20 obtains a signal having the waveform shown in FIG. Can be

The signal is of a duration T ₁ and a half period, the waveform shaping circuit
In 34 a pulse signal of period T ₁ shown in FIG. 3 (B) is obtained.

Further, the timer 36 has a waveform shaping circuit as shown in FIG.
A timer signal that rises at the first pulse input of 34 is obtained, and its time-up time T ₄ (see Fig. 4)
It is set to be longer than T _1.

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

Then, the timer signal of the timer circuit 38 has a period as shown in FIG. 3D after the timer signal of the timer circuit 36 rises.
T ₂ has elapsed is risen when the timer circuit 38 has timed the bias circuit 40 by the rising
, The bias coil 42 is energized.

Therefore, while reading the magnetic card 10, the magnetic card
A weak magnetic field is obtained from the magnetic head 20 to the bias coil by the bias coil.

For this reason, unauthorized magnetic card 10 by magnetic copying
When inserted into the memory card, the information is erased from the middle with a weak magnetic field while the recorded information is being read.
Note abuse 10 is prevented, when the inlet 12 is normal, low coercive force magnetic card 10 as commuter ticket is inserted, the half period T ₃ of the signals shown in FIG. 4 (A) Is the reading coil 26 or the amplification circuit 28
Obtained in a long waveform shaped pulse periodicity than the time-up time T ₄ of the timer circuit 36 shown in FIG. (C) is obtained by the waveform shaping circuit 34.

Therefore, the timer circuit 38 does not time-up, so that the bias coil 42 is not energized by the bias circuit 40. As a result, the stored contents of the legitimate magnetic card 10 such as a commuter pass are erased by the magnetic head 20. Without being read.

As described above, according to the present embodiment, instead of unconditionally applying a magnetic field for erasing unauthorized information to the magnetic card 10 inserted into the insertion slot 12, the inserted magnetic card
Only when it is determined that 10 is a high coercivity magnetic card 10 or a magnetic card 10 on which illegal information by magnetic copying has been recorded, before the recording information of the magnetic card 10 is read by the read coil 26, Bias coil of magnetic head 20
A magnetic field for erasing unauthorized information recorded on the magnetic card 10 is applied by 42, and the magnetic field is not applied in the case of a regular low coercive force magnetic card. The illegal information on the magnetic card 10 on which the illegal information has been recorded can be erased without any adverse effect such as erroneous erasure of the recorded information, and the illegal use of such a magnetic card can be reliably prevented.

For this reason, according to the present embodiment, the repetition frequency of FM recording of a magnetic card such as a prepaid card has a high coercive force card recording and the FM recording of a magnetic card such as a
It is possible to use a single magnetic card reader to handle both low repetition frequency recording and coercivity card recording.

FIG. 5 shows the overall configuration of the second embodiment. In this embodiment, the magnetic heads 4
6 is newly provided.

The magnetic head 20 is not provided with the bias coil 42 shown in FIG.
46 are provided.

Therefore, in the present embodiment, before the magnetic card 10 having a high coercive force inserted into the slot 12 reaches the magnetic head 20, it passes through the magnetic head 46, and a weak magnetic field is applied thereto from the magnetic head 46 in advance.

According to the present embodiment, the reading coil 26 and the bias coil 42
Are provided separately for the magnetic heads 20 and 46, so that the fluctuation of the magnetic field due to the noise of the bias coil 42
In the bias coil 42
It is not necessary to take measures to prevent noise from entering the system.

In the second embodiment, as in the first embodiment, the waveform shaping circuit 34, the timer circuit 36, and the timer circuit 38
This constitutes a recording density determination unit described in the claims.

FIG. 6 shows a third embodiment. In this embodiment, a permanent magnet 48 and a solenoid 50 are provided by a magnetic head 46 shown in FIG.
Is used instead of

And the permanent magnet 48 is a magnetic card by the solenoid 5
The magnetic card 10 is driven forward and backward with respect to the transport path 10, and a weak magnetic field is applied to the magnetic card 10 from the permanent magnet 48 which is driven close to the transport path during transport.

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

For this reason, the reading level of the high coercive force card does not decrease, so that it is not necessary to accurately determine the distance from the magnetic card 10 that applies a weak magnetic field as in the case of a magnetic head, and the mechanism can be simplified. Becomes

In the third embodiment, similarly to the first embodiment, the waveform shaping circuit 34, the timer circuit 36 and the timer circuit 38 are used.
This constitutes a recording density determination unit described in the claims.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of the first embodiment, and FIG.
FIG. 3 is a schematic explanatory view of the configuration of the first embodiment, FIGS. 3 and 4 are waveform diagrams of signals in respective parts of the first embodiment, and FIG.
FIG. 6 is an explanatory diagram of the configuration of the third embodiment, and FIG. 6 is an explanatory diagram of the configuration of the third embodiment. 10 magnetic card 14 card transport mechanism 20 magnetic head 26 reading coil 28 amplifying circuit 34 waveform shaping circuit 36, 38 timer circuit 40 bias circuit 42 bias coil 46 …… Magnetic head 48 …… Permanent magnet 50 …… Solenoid

Claims (1)

(57) [Claims] 1. A magnetic card reader for reading FM recording information recorded on a magnetic card by a magnetic head, wherein a repetition frequency of FM recording of the magnetic card inserted based on a read signal from the magnetic head has a high coercive force. Judging means for judging whether or not it is for recording, if the repetition frequency of FM recording of the magnetic card inserted by the judging means is judged to be for high coercivity card recording, A magnetic field for erasing low coercive force information is applied before the magnetic head completes reading the information recorded on the magnetic card, while the repetition frequency of FM recording on the magnetic card is determined to be for low coercive force card recording. And a magnetic field applying unit that does not apply the magnetic field for erasing the low coercive force information when the magnetic card reader performs the above operation.