JPH03177993A - Magnetic card reader - Google Patents

Abstract

PURPOSE:To surely detect an abnormal operation even when someone performs an operation to prevent a residual display hole being punched by providing a circuit which judges whether or not a punch performs a normal punching operation based on a current waveform conducted to the coil of an electromagnetic plunger. CONSTITUTION:A resistor 29 to take out a current conducted to the coil 16 as a voltage value is provided, and a taken-out voltage is stored in a capacitor 32 via a rectifier element 31, then, a voltage with peak value is held. Also, the voltage changing from time to time out of the voltages taken out at the resistor 29 is supplied to a voltage comparator 33 via a terminal 33a, and is compared with a peak voltage, and when a voltage difference arrives at a prescribed value, a pulse signal 34 is issued from the voltage comparator 33. The electromagnetic plunger is operated normally while the signal is issued, and it is judged that abnormality occurs in the operation of the electromagnetic plunger when it is not issued. In such a way, the abnormal operation can be surely detected even when the operation to prevent to the residual display hole being punched on a magnetic card is performed by someone.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic card reading device, and more particularly to a magnetic card reading device having a function of preventing abnormal operations by a card user.

[Conventional technology]

FIG. 5 shows a schematic configuration of a conventional magnetic card reading device. 1 is an insertion port. When a magnetic card 2 such as a telephone card is inserted into this insertion slot 1, it is inserted into the magnetic sensor 3.
is detected and the gate 4 is opened. This gate 4 is normally biased in the closing direction by a coil spring 5. The gate 4 is connected to the iron core 6, and when a current is passed through the coil 7, the iron core 6 is drawn upward as shown by the dotted line in the figure, and the gate 4 is opened. Iron core 6 and coil 7 constitute an electromagnetic plunger.

After the signal from the magnetic card 2 passes through the gate 4, it is read by the magnetic head 8. During this time, the magnetic card 2 is transported by rollers 10 to 12, and the rear roller 1
A punch 13 for drilling is arranged between the roller 1 and the roller 12. An iron core 14 is fixed to the punch 13, and this iron core 14 is normally urged upward by a coil spring 15. When a current is passed through the electromagnetic coil 16, the iron core 14 is attracted as shown by the dotted line in the figure, and the punch 13 at the tip protrudes downward, as shown in FIG.
Display hole 1 for displaying the remaining power at a predetermined position on the magnetic card 2
8 is perforated.

[Problem to be solved by the invention]

By the way, some card users of this type intentionally leave the gate 4 open by inserting a foreign object into the insertion slot 1 as a prank or the like, but even in this case, the above-mentioned reading device cannot read the card. Execute the action as is. However, this leaves gate 4 open after use, so
There is a problem in that rainwater, dust, etc. enter through the insertion port 1 and damage internal equipment.

Furthermore, some card users do not like the display hole 18 to be punched in the magnetic card 2 such as a telephone card. For example, as shown in FIG. Some people use it by pasting it on the upper surface of the planned position, so that even if the punch 13 protrudes downward, it will not be punctured. Even in such a case, the above-mentioned reading device performs the reading operation and the remaining power of the telephone card decreases, but
After use, a card without the display hole 18 being punched comes out of the reading device, so there is a problem in that it is visually indistinguishable from an unused card.

In any of these cases, when current is passed through,
This phenomenon occurs when the iron cores 6 and 14 that make up the electromagnetic plunger do not move up and down, so conventionally, a sensor is provided to detect whether or not the iron cores 6 and 14 move up and down based on the distance traveled.
A device has been proposed that uses detection by this sensor to prevent abnormal operations by the user. but,
This requires an extra sensor, increases the size of the structure, and complicates the configuration.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a magnetic card reading device which solves the problems of the above-mentioned conventional techniques and which has a simple configuration and can prevent abnormal operations by a card user.

[Means to solve the problem]

In order to achieve the above object, the invention according to claim 1,
In a magnetic reading device that has a punch that is driven by an electromagnetic plunger and punches a hole for displaying the remaining amount of usage in a magnetic card, the current waveform leading to the coil of the electromagnetic plunger is detected, and the punch operates normally based on changes in this current waveform. The apparatus is characterized in that it includes a determination circuit that determines whether or not a drilling operation has been performed.

Further, the invention according to claim 2 provides a magnetic card reading device having a gate driven by an electromagnetic plunger to open and close a magnetic card insertion slot, in which a current waveform leading to a coil of the electromagnetic plunger is detected, and a change in the current waveform is detected. The present invention is characterized in that it includes a determination circuit that determines whether the gate has opened and closed normally based on the following.

[For production]

According to the invention set forth in claim 1, if someone operates the magnetic card so that the remaining amount display hole is not punched, an abnormality appears in the current waveform leading to the coil of the electromagnetic plunger. According to the invention, if someone intentionally inserts a foreign object into the insertion port, an abnormality will appear in the current waveform leading to the coil of the electromagnetic plunger, and the abnormality appearing in the current waveform will be detected by the judgment circuit. It will be judged and definitely detected.

〔Example〕

Hereinafter, an embodiment of the magnetic card reading device according to the present invention will be described with reference to FIGS. 1 to 4, in which the same parts as in FIG. 5 are denoted by the same reference numerals.

FIG. 1 shows a drive circuit for vertically moving a punch 13 for punching a card. In the figure, reference numeral 13 indicates a punch for punching a card, and this punch 13 is fixed to an iron core 14. This iron core 14 is normally urged upward by a coil spring 15. A coil 16 is arranged around the iron core 14, and this coil 16 is connected to an ammeter 23,
It is connected in series to a switch 24 and a power source 25, and a capacitor 26 and a voltmeter 27 are connected in parallel to this power source 25. The iron core 14 and the coil 16 constitute an electromagnetic plunger.

When the switch 24 is closed and current is passed through the coil 16, a magnetic field is generated and the iron core 14 is attracted downward, and the punch 13 at the tip is lowered and positioned directly below it (not shown here). A display hole is punched in a predetermined position of the telephone card to display the remaining capacity. On the other hand, switch 2
4 opens, the coil spring 15 urges the iron core 14 upward. This switch 24 is a switch that turns on and off instantaneously.

FIG. 2 shows changes in the voltage V and current I generated in the drive circuit. The horizontal axis is time T.

When the switch 24 is closed, the change in the voltage V appearing on the voltmeter 27 of the drive circuit takes on the pulse waveform shown in FIG.

Next, assuming that the iron core 14 constituting the electromagnetic plunger does not move even when current is applied, the change in the current I appearing on the ammeter 23 of the drive circuit has a waveform as shown in FIG. However, when the iron core 14 moves, the change in the current I takes on a waveform as shown in FIG. As the iron core 14 moves, the impedance temporarily increases, the current value once drops near code 28, and when the iron core 14 stops moving, the current value rises again, and then changes to a constant value. It is. Note that when the switch 24 is opened, the current value instantaneously becomes zero.

According to this embodiment, FIGS. 2(b) and (C
) is used to determine whether or not there is vertical movement of the iron core 14.

FIG. 3 shows a judgment circuit according to this embodiment.

According to this judgment circuit, a resistor 29 is provided for extracting the current flowing through the coil 16 as a voltage value.

30 is the internal resistance of the coil 16.

The voltage V taken out by the above-mentioned resistor 29 is directly proportional to the current I flowing through the coil 16, and when the value of the current flowing through the coil 16 decreases, the voltage value taken out also drops.

The voltage V taken out by this resistor 29 is stored in a capacitor 32 through a rectifying element 31, and only the peak value voltage (2) is held here. Further, the voltage V which changes from time to time out of the voltage (1) taken out by the resistor 29 is applied to the voltage comparator 33 through the terminal 33a, where it is compared with the above-mentioned peak voltage V applied through the terminal 33b. Then, when the voltage difference ΔV here reaches a predetermined value, a pulse signal 34 is transmitted from the voltage comparator 33.

When this pulse signal 34 is transmitted, as will be described later, the electromagnetic plunger is operating normally, and when this pulse signal 34 is not transmitted, an abnormality has occurred in the operation of the electromagnetic plunger. Therefore, an abnormality in the operation of the electromagnetic plunger is detected by the presence or absence of the pulse signal 34.

Next, the operation of the judgment circuit will be explained.

In FIG. 4, the vertical axis shows voltage V, and the horizontal axis shows time T. When current flows through the coil 16 and the iron core 14 that makes up the plunger moves, the impedance increases,
- Over time, the value of the current I passing through the coil 16 decreases. This decrease in current (2) appears as a drop in voltage V in the drive circuit of FIG. That is, the voltage ■ of the drive circuit is curve 41
It rises as shown by , drops once near time t1, and then rises again. At this time, the voltage ■ which changes from time to time appears at the terminal 33a of the voltage comparator 33. on the other hand,
As shown by a curve 42, the voltage V appearing at the terminal 33b rises slightly later than the curve 41, and is held at the first peak, that is, near time t2. Rise.

According to this, the voltage ■ appearing at the terminal 33b is the voltage at the terminal 33a.
Near time t3, it is lower by about ΔV' than the voltage ■ appearing at , and on the contrary, near time t1, it is higher by about Δ■.

On the other hand, if the iron core 14 constituting the plunger does not move even when current flows through the coil 16, the voltage ■ appearing at the terminal 33a of the voltage comparator 33 changes from time to time, and the curve 4
It becomes as shown in 3. At this time, as shown by a curve 44, the voltage V appearing at the terminal 33b rises slightly later than the curve 43, and rises almost the same as the curve 43 while maintaining a slight voltage difference.

As is clear from these, current flows through the coil 16,
When the iron core 14 constituting the plunger moves and the punch 13 performs a normal drilling operation, a large voltage difference ΔV occurs near time tl, and on the other hand, even if current flows through the coil 16, the punch 13 does not perform the drilling operation. In case of large voltage difference Δ
V does not occur.

Further, in the former case, the curve 41 and the curve 42 intersect, whereas in the latter case, the curve 43 and the curve 44 do not intersect.

Therefore, if the voltage comparator 33 is configured to oscillate a pulse when a voltage difference ΔV occurs or when the curves intersect, the punch 13 will operate normally when the pulse oscillates. Therefore, it is possible to reliably judge whether or not there is a normal drilling operation. In addition, if an alarm is connected to the voltage comparator 33, an alarm can be sounded if the punch 13 does not perform the punching operation, and if a card collection mechanism is added, if an abnormality is detected, the alarm will sound. It is also possible to collect the magnetic card 2 such as a telephone card, thereby preventing crimes caused by abnormal operations. Although the curve 45 indicates the end of the pulse, it is necessary to reset the voltage comparator 33 before the end of the pulse to prevent the voltage comparator 33 from malfunctioning.

The determination circuit for determining whether or not the punch 13 has performed a normal drilling operation has been described above.
A determination circuit for determining whether the opening/closing operation has been performed normally can be configured in the same manner. In this case, in FIG. 3, the punch 13 may be replaced with the gate 4. Accordingly, it is possible to reliably determine whether the gate 4 has opened and closed normally.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a judgment circuit is provided which detects the current waveform flowing through the coil of the electromagnetic plunger and determines whether or not the punch has performed a normal drilling operation based on a change in the current waveform. Therefore, even if someone operates the magnetic card so that the remaining amount display hole is not punched, the abnormal operation can be reliably detected.

In addition, according to another invention, the device is equipped with a judgment circuit that detects the current waveform flowing through the coil of the electromagnetic plunger and judges whether or not the gate has opened and closed normally based on changes in the current waveform. Even if someone intentionally puts a foreign object in their mouth, the abnormal operation can be reliably detected.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a magnetic card reading device according to the present invention, FIGS. 2(a) to (c) are diagrams showing voltage and current waveforms flowing through the coil of the electromagnetic plunger, and FIG. Similarly, FIG. 4 is a circuit diagram showing the judgment circuit, and FIG.
The figure shows the constituent countries of a conventional magnetic card reading device, and FIG. 6 is a plan view showing the magnetic card. 1...Insertion slot, 2...Magnetic card, 4...Gate, 6゜14...Iron core, 7.16...Coil, 13.
... Punch, 18... Remaining amount display hole, 41.42...
Voltage waveform at normal time, 43.44... Voltage waveform at abnormal time.

Claims (1)

[Scope of Claims] 1. In a magnetic card reading device having a punch driven by an electromagnetic plunger to punch a hole indicating the remaining amount of usage in a magnetic card, a current waveform flowing through the coil of the electromagnetic plunger is detected, and the current waveform is detected. A magnetic card reading device comprising a determination circuit that determines whether a punch has performed a normal punching operation based on a change in waveform. 2. In a magnetic card reader having a gate driven by an electromagnetic plunger to open and close a magnetic card insertion slot, the current waveform flowing through the coil of the electromagnetic plunger is detected, and the gate opens and closes normally based on changes in this current waveform. A magnetic card reader characterized in that it is equipped with a determination circuit that determines whether or not it has operated.