JP2004259322A - Apparatus and method for writing magnetic information - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the leakage of written information caused by a change in current consumption. <P>SOLUTION: Information is read from a plurality of tracks of a magnetic card and stored into a memory. After the reception of the written information from a host device, determination is made as to whether the received written information is information to be written in one track or not. If the written information is not information to be written in one track, the written information is written in a plurality of writing target track at the same time. If the written information is information to be written in one track, on the other hand, the written information is written in a writing target track, and simultaneously the original information of the track stored in the memory is rewritten in a track which is not a writing target. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnetic information writing device and a magnetic information writing method for writing information to a magnetic recording medium such as a magnetic card, and more particularly to a device for preventing write information from leaking due to a change in current consumption when writing information. It is.
[0002]
[Prior art]
A magnetic card reader / writer is known as a magnetic information writing device for writing information on a magnetic recording medium such as a magnetic card. Generally, when a magnetic card is inserted, the magnetic card reader / writer writes information on the magnetic card by a magnetic head while transporting the magnetic card inside. At this time, a write current corresponding to the write information to be written on the magnetic card is supplied to the magnetic head, whereby the magnetization of the magnetic material of the magnetic stripe of the magnetic card is reversed at predetermined intervals to magnetically record the write information. Some magnetic card reader / writers simultaneously write different information on a plurality of tracks formed on a magnetic stripe of a magnetic card. This is because a magnetic head is provided with a plurality of cores corresponding to each track of a magnetic card, and a write current according to write information is supplied to a coil wound around each core, so that a plurality of tracks can be simultaneously applied to a plurality of tracks. Write different information.
[0003]
On the other hand, there is a magnetic card in which a magnetic stripe is formed of a magnetic material having high coercive force so that recorded magnetic information is not changed even when the magnetic card is brought close to a magnet or a television in a bag. A magnetic card reader / writer that writes information on such a high coercivity type magnetic card writes information by passing a large write current of about 200 to 400 mA to the magnetic head. On the other hand, in the case of writing information on a low coercivity type magnetic card, a small write current of about 20 to 30 mA flows through the magnetic head. However, when information is written to a magnetic card with a large write current of about 200 to 400 mA, the change in current consumption of the entire magnetic card reader / writer increases, and the write information is transmitted to a third party from the change in current consumption as described below. There is a problem of leakage. The magnitude of the write current flowing through the magnetic head to write information on the magnetic card is large or small according to the characteristics of the magnetic head. Nevertheless, a larger write current must be applied to the magnetic head when writing information to a high coercivity type magnetic card than when writing information to a low coercivity type magnetic card.
[0004]
11 and 12 are diagrams for explaining the above problem. FIG. 11 shows a magnetic card reader / writer used in an information processing apparatus, and FIG. 12 shows a write current and a current consumption in the magnetic card reader / writer. Shows the change over time. In FIG. 11, a magnetic card reader / writer 51 installed in an information processing device 50 such as an automatic cash transaction processing device is supplied with current from a power supply unit 54 of the information processing device 50 via a lead L4. . When writing information to a high coercivity type magnetic card 52 used as a credit card or a cash card, the magnetic card reader / writer 51 transfers the write information from the control unit 53 of the information processing device 50 via the lead line L3. Receive. “1” and “0” shown in FIG. 12A are the write information received at this time.
[0005]
The magnetic card reader / writer 51 uses the F2F (Two Frequency Coherent Phase Encoding) recording method to magnetically record the received write information on the magnetic stripe of the magnetic card 52 as shown in FIG. 12C, a write current (I = about 200 to 400 mA) having a pulse waveform as shown in FIG. 12C is applied to a magnetic head (not shown). At this time, every time the polarity (+ and-) of the write current changes, the current consumption consumed by the entire magnetic card reader / writer 51 changes as shown in FIG. For this reason, when a current meter is connected to a lead wire L4 shown in FIG. 11 and a change in the current consumption is measured by a third party who attempts to illegally acquire the information of the card, the change in the current consumption is calculated as follows. As shown in FIG. 12 (e), the information of “1” and “0” is read, such as “1” when the interval of the fluctuation of the consumption current is narrow, and “0” when the interval is wide, and writes it on the magnetic card 52. However, there arises a problem that the written information is leaked to a third party. Further, there is a problem that information unique to the magnetic card 52 such as a credit card number and a bank account number is restored from the leaked write information.
[0006]
Japanese Patent Application Laid-Open No. H11-163873 discloses that an integrator is mounted in an IC card as a device for changing the current consumption consumed by the entire IC card, thereby erasing and averaging fluctuations in the current consumption. There is described a technique for preventing a third party from restoring information written in a memory in a card. However, erasing and averaging the fluctuation of the current consumption can be performed only because the IC card has a very small write current of about 200 μA and a small fluctuation of the current consumption. Is very large, about 200 to 400 mA, and the fluctuation of the current consumption is large. It is very difficult to eliminate and average the fluctuation of the current consumption.
[0007]
[Patent Document 1]
JP 2002-508549 A
[0008]
[Problems to be solved by the invention]
The present invention solves the above problems, and an object of the present invention is to provide a magnetic information writing device and a magnetic information writing method capable of preventing write information from leaking due to a change in current consumption. Is to do.
[0009]
[Means for Solving the Problems]
A magnetic information writing apparatus according to the present invention includes a magnetic head capable of simultaneously writing different information on a plurality of tracks provided on a magnetic recording medium, and a receiving unit that receives write information to be written on the magnetic recording medium from a higher-level device. Determining means for determining whether or not the write information received by the receiving means is information to be written to only one track; and determining that the write information is not information to be written to only one track by the determining means. The magnetic head is controlled to write the write information to a plurality of tracks to be written at the same time. If the determination unit determines that the write information is information to be written to only one track, the magnetic head is controlled to control the magnetic head. At the same time as writing information to the track, It is provided with a writing means for writing the different information and viewing information.
[0010]
In the magnetic information writing method according to the present invention, after receiving the write information to be written to the magnetic recording medium from the host device, it is determined whether the received write information is information to be written to only one track. If it is determined that the write information is not information to be written to only one track, the magnetic head is controlled to simultaneously write the write information to a plurality of tracks to be written. On the other hand, if it is determined that the write information is information to be written into only one track, the magnetic head is controlled to write the write information to the write target track, and at the same time, the write information is different from the write information to the non-write target track. Write information.
[0011]
As described above, if different information is always written to a plurality of tracks of the magnetic recording medium at the same time, write currents having different waveforms flow through the magnetic head when writing information, so that the current consumption is affected each time the polarity of each write current changes. Accordingly, the variation in current consumption becomes complicated. For this reason, it is possible to prevent write information from leaking due to a change in current consumption.
[0012]
Further, in the present invention, the magnetic head can read information from a plurality of tracks of the magnetic recording medium, and controls the magnetic head to write the information to the plurality of tracks of the magnetic recording medium before the writing unit writes the information. There is provided reading means for reading information from the track and storing the read information in a memory. In this case, the writing unit writes information read from the track by the reading unit and stored in the memory as information different from the above-described write information. When the information originally recorded on the track not to be written is thus written back, the information on the track is not changed before and after writing, and the originally recorded information is not lost.
[0013]
In addition, in the present invention, typically, the receiving unit individually receives write information from the higher-level device for each track, and the determining unit determines whether the write unit has received write information for a plurality of tracks. It is determined that the information is not information to be written to only one track, and when the receiving unit receives the write information for one track, it is determined that the write information is information to be written to only one track. As described above, when it is determined whether or not the write information is information to be written into only one track based on the reception status of the write information by the receiving unit, for example, the write information is collectively received from a higher-level device, and Compared to the case where it is determined from the data length or the like whether or not the write information is information to be written to only one track, the determination can be easily made without performing a complicated operation.
[0014]
In addition, a magnetic information writing apparatus according to another embodiment of the present invention includes a magnetic head capable of simultaneously writing different information on a plurality of tracks provided on a magnetic recording medium, and a write current that is substantially equal to a write current flowing through the magnetic head. Or a noise generating means for generating noise by consuming a predetermined current larger than that, a receiving means for receiving write information to be written to the magnetic recording medium from a higher-level device, and the write information received by the receiving means being stored in one track. Determining means for determining whether the information to be written is only the information to be written into the plurality of tracks; The write information is written simultaneously, and the write information is written to only one track by the determination means. If it is determined that the writing information is provided with writing means for writing the write data to the track to be written by controlling the magnetic head in the state that caused the noise by the noise generating means.
[0015]
In the magnetic information writing method according to another embodiment of the present invention, after receiving write information to be written on a magnetic recording medium from a higher-level device, it is determined whether the received write information is information to be written into only one track. judge. If it is determined that the write information is not information to be written to only one track, the magnetic head is controlled to simultaneously write the write information to a plurality of tracks to be written. On the other hand, when it is determined that the write information is information to be written into only one track, a state in which noise is generated by consuming a predetermined current equal to or larger than the write current flowing to the magnetic head. The magnetic head is controlled to write the write information on the track to be written.
[0016]
In this way, when different information is simultaneously written to a plurality of tracks of the magnetic recording medium, write currents having different waveforms flow through the magnetic head, so that the current consumption is affected each time the polarity of each write current changes. Fluctuates, and changes in current consumption become complicated. Further, when information is written to only one track of the magnetic recording medium, noise is generated by the noise generating means, and the generated noise is superimposed on the current consumption, thereby complicating the change in the current consumption. Therefore, it is possible to prevent write information from leaking due to a change in current consumption, regardless of the number of tracks on which information is written.
[0017]
Further, in the magnetic information writing device according to the other embodiment, in order to write the write information to the track by the F2F recording method, a write current control means for controlling a write current flowing to the magnetic head is provided. In this case, the noise generation unit generates noise at a timing at which the current control unit controls the write current to write the information of the logic “1” of the F2F recording method. This makes it impossible to read the information of logic "0" of the F2F recording method due to the change in the current consumption, and it is possible to more reliably prevent the write information from leaking.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a diagram illustrating a magnetic card reader / writer used in an information processing apparatus. In FIG. 1, reference numeral 20 denotes an information processing apparatus such as an automatic cash transaction processing apparatus, 1 denotes a magnetic card reader / writer installed in the information processing apparatus 20, and 2 denotes a high coercive force type used as a credit card or a cash card. Magnetic card. Reference numeral 3 denotes a roller for transporting the magnetic card 2 inserted into the magnetic card reader / writer 1 from the insertion slot 1a in the F or B direction, and reference numeral 4 denotes a photosensor (for detecting the position of the magnetic card 2 to be transported). Hereinafter, referred to as a sensor). Reference numeral 5 denotes a magnetic head according to the present invention, which writes or reads information in contact with the magnetic card 2 to be conveyed. Reference numeral 21 denotes a control unit of the information processing device 20, which transmits an operation instruction to the magnetic card reader / writer 1 and write information for writing to the magnetic card 2. L1 is a communication lead for the control unit 21 and the magnetic card reader / writer 1 to communicate with each other. Reference numeral 22 denotes a power supply unit for supplying a current to each unit of the information processing apparatus 20, and reference numeral 23 denotes a power supply plug for connecting the power supply unit 22 to an external AC outlet. L2 is a power supply lead wire for supplying a current from the power supply unit 22 to the magnetic card reader / writer 1. In the above, the magnetic card reader / writer 1 constitutes the magnetic information writing device of the present invention, the information processing device 20 constitutes the host device of the present invention, and the magnetic card 2 constitutes the magnetic recording medium of the present invention.
[0019]
FIG. 2 is a diagram showing the outer shape of the magnetic card 2 and the structure of the magnetic head 5. In FIG. 2, reference numeral 2a denotes a front end of the magnetic card 2 when inserted into the magnetic card reader / writer 1, and 2b denotes a rear end. Reference numeral 2c denotes a magnetic stripe provided on a surface of the magnetic card 2 which is in contact with the magnetic head 5, and is formed with three tracks T1 to T3. Hereinafter, T1 is a first track, T2 is a second track, and T3 is a third track. Each of these tracks T1 to T3 is formed of a magnetic material having a high coercive force. On the other hand, the magnetic head 5 is provided with three cores 5a to 5c so as to be in contact with the three tracks T1 to T3 of the magnetic stripe 2c, respectively. When writing information on the magnetic card 2, if a large write current of about 200 to 400 mA is applied to a coil (not shown) wound around each of the cores 5 a to 5 c in accordance with the information to be written, three tracks T 1 to T 3 Different information can be written at the same time. Further, when reading information from the magnetic card 2, if a change in magnetic force of each of the tracks T <b> 1 to T <b> 3 is detected by the three cores 5 a to 5 c, information can be read from the three tracks T <b> 1 to T <b> 3 at the same time. The magnetic head 5 can write or read information on one track by one core, or write or read information on two tracks at the same time by two cores. it can.
[0020]
FIG. 3 is a block diagram showing an electrical configuration of the magnetic card reader / writer 1. In FIG. 3, reference numeral 6 denotes a CPU for controlling each unit of the magnetic card reader / writer 1, reference numeral 7 denotes a memory composed of a ROM, RAM, and EEPROM, and reference numeral 8 denotes a memory for mutually communicating with the control unit 21 (FIG. 1) of the information processing apparatus 20. Communication section. The communication unit 8 receives operation instructions and write information for writing to the magnetic card 2 transmitted from the control unit 21. In the present embodiment, the control unit 21 adds track information for designating a track to be written to the write information, transmits the information individually for each of the tracks T1 to T3 of the magnetic card 2, and the communication unit 8 Such information is individually received for each of the tracks T1 to T3. When the communication section 8 receives the write information, the CPU 6 determines whether or not the write information is information to be written to only one track of the magnetic card 2. In this embodiment, when the communication unit 8 receives write information for a plurality of tracks, the CPU 6 determines that the write information is not information to be written to only one track, and the communication unit 8 transmits the write information for one track. When received, it is determined that the write information is information to be written to only one track. In addition to this, for example, the communication unit 8 collectively receives write information from the control unit 21, and the CPU 6 determines whether the write information is information to be written to only one track based on the data length or the like of the information. However, as in the present embodiment, it is more complicated to determine whether the write information is information to be written into only one track based on the reception status of the write information by the communication unit 8. Can be easily determined without performing the above. The communication unit 8 forms a receiving unit in the present invention, and the CPU 6 forms a determining unit in the present invention.
[0021]
Reference numeral 9 denotes a write control unit which controls a write current flowing through the cores 5a to 5c (FIG. 2) of the magnetic head 5 according to the information to be written when writing information to the tracks T1 to T3 of the magnetic card 2. In the present embodiment, writing of information to the magnetic card 2 is performed by an F2F (Two Frequency Coherent Phase Encoding) recording method. This method is sometimes called an FM (Frequency Modulation) recording method. The CPU 6 controls the magnetic head 5 by the write control unit 9 to write the write information received by the communication unit 8 on the tracks T1 to T3 of the magnetic card 2. Reference numeral 10 denotes a read control unit which, when reading information from the tracks T1 to T3 of the magnetic card 2, generates information from a change in magnetization of the tracks T1 to T3 detected by the cores 5a to 5c of the magnetic head 5. The CPU 6 controls the magnetic head 5 by the read control unit 10 to read information from the tracks T1 to T3 of the magnetic card 2. Then, the read information is transmitted to the information processing device 20 by the communication unit 8 or stored in the memory 7. After that, the CPU 6 controls the magnetic head 5 by the write control unit 9 to write back the information stored in the memory 7 to the read tracks T1 to T3. The CPU 6 and the writing control unit 9 constitute a writing unit in the present invention, and the CPU 6 and the reading control unit 10 constitute a reading unit in the present invention. The information read from the tracks T1 to T3 and stored in the memory 7 is "information different from write information" in the present invention.
[0022]
Reference numeral 11 denotes a motor control unit that controls the rotation direction and the number of rotations of the motor 12. The CPU 6 drives the motor 12 to rotate forward or reverse by the motor control unit 11 to rotate the roller 3 (FIG. 1) to convey the magnetic card 2 in the F direction or the B direction. Reference numeral 13 denotes a rotary encoder (hereinafter, referred to as an encoder) that detects the number of rotations of the motor 12. Reference numeral 14 denotes a card position detecting unit which detects the position of the magnetic card 2 based on the switching signal of the sensor 4 (FIG. 1). Further, the card position detecting unit 14 is adapted to switch the magnetic card 2 to a magnetic card reader / writer based on a switching signal of a sensor (not shown) provided in the vicinity of the roller 3 closest to the direction B among the plurality of rollers 3 shown in FIG. 1 is detected. Reference numeral 15 denotes a power supply unit, which sends a current supplied from the power supply unit 22 (FIG. 1) of the information processing apparatus 20 to the respective units of the magnetic card reader / writer 1 via the above-described power supply lead line L2 (FIG. 1).
[0023]
FIG. 4 is a flowchart showing a procedure of a write operation of the magnetic card reader / writer 1, and each process is executed by the CPU 6. In FIG. 4, when the magnetic card 2 is inserted into the magnetic card reader / writer 1, the CPU 6 drives the motor 12 to take the magnetic card 2 inside. While the magnetic card 2 is being conveyed, the read control unit 10 controls the magnetic head 5 to read information from a plurality of tracks T1 to T3 of the magnetic card 2 and stores the read information in the memory 7 for each track T1 to T3. It is stored (step S11). At this time, the read information is sent to the control unit 21 of the information processing device 20 by the communication unit 8 at the same time. When the communication unit 8 receives the write instruction from the control unit 21 (step S12: YES), the communication unit 8 subsequently receives the write information from the control unit 21 for each of the tracks T1 to T3 (step S13). .
[0024]
When the write information is received, it is determined whether the write information is information to be written into only one track of the magnetic card 2 (step S14). If the communication section 8 has received the write information for one track in step S13, it is determined that the write information is information to be written to only one track (step S14: YES), and the write information is written to the write control section 9 To prepare for writing the information on one track to be written by the magnetic head 5 (step S15). Subsequently, the information of the track not to be written, which is stored in the memory 7 in step S11, is sent to the write controller 9, and the magnetic head 5 prepares to write the information on the track (step S16). That is, a preparation is made so that the information originally recorded on the track not to be written is rewritten (overwritten) on the same track. When the preparation for writing the respective information is completed in this way, the magnetic head 5 is controlled by the writing control unit 9 while the motor 12 is driven and the magnetic card 2 is conveyed, and the information is simultaneously written on the plurality of tracks T1 to T3 (step S1). S18). As a result, the write information received from the control unit 21 is written to the track to be written (for example, track T1), and the originally recorded information is written back to the tracks that are not to be written (for example, tracks T2 and T3). When the writing is completed, the communication unit 8 notifies the control unit 21 that the writing is completed, and ends the processing.
[0025]
On the other hand, if the communication unit 8 has received the write information for a plurality of tracks in step S13, it is determined in step S14 that the write information is not information to be written to only one track (step S14: NO), and each write is performed. The information is sent to the write control unit 9, and the magnetic head 5 prepares to write the information on a plurality of tracks to be written (step S17). Then, while driving the motor 12 to convey the magnetic card 2, the write control unit 9 controls the magnetic head 5 to write information on a plurality of tracks simultaneously (step S18). As a result, the write information received from the control unit 21 is written to the plurality of tracks to be written. When the writing is completed, the communication unit 8 notifies the control unit 21 that the writing is completed, and ends the processing.
[0026]
FIG. 5 is a diagram showing a temporal change in the write current and the current consumption of the magnetic card reader / writer 1 when the write information is information to be written into only one track. In FIG. 5, "1" and "0" shown in (a) are write information to be written to one track to be written. Here, the track to be written is the first track T1. In order to write the write information shown in (a) on the first track T1, a write current having a pulse waveform as shown in (b) is applied to the core 5a (FIG. 2) of the magnetic head 5 corresponding to the first track T1. Flow 1 ▼. When a write current (1) having such a waveform is passed and information is written only on the first track T1 as in the prior art, every time the polarity (+ and-) of the write current (1) changes, (c) As shown in ()), the current consumption consumed by the entire magnetic card reader / writer 1 changes in accordance with the write current, and when this change in current consumption is acquired by a third party, the write information shown in (a) becomes Will leak.
[0027]
On the other hand, in the procedure described with reference to FIG. 4, the write information is written to the first track T1, and at the same time, the information originally recorded on the tracks not to be written, here the second track T2 and the third track T3, is written. return. For this purpose, write currents (2) and (3) having different pulse waveforms as shown in (d) and (e) are applied to the cores 5b and 5c (FIG. 2) of the magnetic head 5 corresponding to the tracks T2 and T3, respectively. Shed. As described above, when the write currents (1) to (3) having different waveforms are applied to the respective cores 5a to 5b of the magnetic head 5 to simultaneously write information on the plurality of tracks T1 to T3, the respective write currents Each time the polarity (+ and-) of (1) to (3) changes, the current consumption is affected and fluctuates as shown in (f), and the change in current consumption becomes complicated. That is, a change due to the write currents (2) and (3) is superimposed on the change in the current consumption shown in (c). For this reason, even if the change in the current consumption is acquired by a third party, it is possible to prevent the write information from leaking due to the change in the current consumption. As a result, the problem that information unique to the magnetic card 2 such as a credit card number and a bank account number is restored from the written information does not occur.
[0028]
Also, by writing back the information originally recorded on the tracks T2 and T3 which are not the writing targets, the information on the tracks T2 and T3 is not changed before and after the writing, and the originally recorded information is lost. Not even.
[0029]
Further, in Patent Literature 1, a device including a resistor and a random number signal generator is mounted in an IC card, and a current is randomly flowed by flowing or not flowing a current to the resistor by the random number signal generator. Although the current consumption is changed to prevent a third party from restoring the information written in the memory in the IC card, if a device that consumes such a random current is provided in a magnetic card reader / writer, At the time of writing information to the card, current is always consumed in a random manner, and the current consumption of the entire magnetic card reader / writer increases. When writing information to one track of the magnetic card, there is no problem even if the current consumption increases as described above. However, when writing information to a plurality of tracks of the magnetic card simultaneously, the information flows to each core of the magnetic head. Since the current consumption is extremely large due to the writing current, if the current consumption is large as described above, the temperature of the entire magnetic card reader / writer becomes high, and the heat causes the coils of the cores of the magnetic head to be disconnected. Or the magnetic card in contact with the magnetic head may be melted. However, according to the above-described embodiment, it is not necessary to provide a special device in the magnetic card reader / writer 1 as in Patent Document 1, so that when information is simultaneously written to a plurality of tracks T1 to T3, current consumption increases. Therefore, the temperature of the entire magnetic card reader / writer 1 does not become high, and the heat does not cause the coils of the cores 5a to 5c of the magnetic head 5 to be disconnected or the magnetic card 2 in contact with the magnetic head 5 to be melted.
[0030]
6 to 9 are diagrams for explaining another embodiment of the present invention. First, FIG. 6 is a block diagram illustrating an electrical configuration of a magnetic card reader / writer 1 according to another embodiment. In the figure, the same parts as those in FIG. 3 are denoted by the same reference numerals. 6, the magnetic card reader / writer 1 of the present embodiment includes a noise generator 16 in addition to the configuration described in FIG. FIG. 7 shows an example of a specific configuration of the noise generator 16. In FIG. 7, reference numeral 17 denotes a bridge circuit including transistors TR1 to TR4, a resistor R, a coil L, and capacitors C1 and C2. Reference numeral 18 denotes a pulse generator that outputs a pulse signal. Reference numeral 19 denotes a switch control circuit which controls switching of the four transistors TR1 to TR4 of the bridge circuit 17 between an ON state and an OFF state by a pulse signal input from the pulse generator 18.
[0031]
When the switch control circuit 19 turns on the transistors TR1 and TR4 and turns off the transistors TR2 and TR3, a current flows in the bridge circuit 17 in the X direction. When the switch control circuit 19 turns on the transistors TR2 and TR3 and turns off the transistors TR1 and TR4, a current flows through the bridge circuit 17 in the Y direction. When the direction in which the current flows is switched in this manner, the circuit consumption current consumed in the bridge circuit 17 changes, and noise occurs in the magnetic card reader / writer 1. The magnitude of the circuit consumption current is set to be equal to or larger than the write current flowing through the magnetic head 5 by adjusting the capacitance of the capacitor C1, and the magnitude of the noise is determined by the circuit consumption current. According to the size of The switching of the transistors TR <b> 1 to TR <b> 4 by the switch control circuit 19 controls the write current flowing to the magnetic head 5 for writing the information of logic “1” by the write control unit 9 (FIG. 6) by the F2F recording method, as described later. It is performed at the timing of performing. Therefore, the circuit current consumption changes at that timing, and noise occurs. The noise generator 16 constitutes a noise generator in the present invention, and the write controller 9 constitutes a current controller in the present invention.
[0032]
FIG. 8 is a flowchart showing a procedure of a write operation by the magnetic card reader / writer 1 of FIG. 6, and each process is executed by the CPU 6. 8, when the magnetic card 2 is inserted into the magnetic card reader / writer 1, the CPU 6 drives the motor 12 to take the magnetic card 2 into the inside. Then, while transporting the magnetic card 2, the read control unit 10 controls the magnetic head 5 to read information from a plurality of tracks T1 to T3 of the magnetic card 2 (step S21). At this time, the read information is sent to the control unit 21 of the information processing device 20 by the communication unit 8. When the communication unit 8 receives the write instruction from the control unit 21 (step S22: YES), the communication unit 8 subsequently receives the write information from the control unit 21 for each of the tracks T1 to T3 (step S23). .
[0033]
When the write information is received, it is determined whether the write information is information to be written into only one track of the magnetic card 2 (step S24). If the communication unit 8 has received the write information for one track in step S23, it is determined here that the write information is information to be written to only one track (step S24: YES), and the write information is written. The information is sent to the control unit 9 and is prepared so that the information can be written on one track to be written by the magnetic head 5 (step S25). Then, generation of noise is started by the noise generation unit 16 (step S26), and the magnetic head 5 is controlled by the write control unit 9 while driving the motor 12 and transporting the magnetic card 2 in a state where the noise is generated. Then, write information is written to one track to be written (step S27). When the writing is completed, the noise generation unit 16 stops generating noise (step S30), and the communication unit 8 notifies the control unit 21 that the writing has been completed, and ends the processing.
[0034]
On the other hand, if the communication unit 8 has received write information for a plurality of tracks in step S23, it is determined in step S24 that the write information is not information to be written to only one track (step S24: NO), and each write The information is sent to the write control unit 9, and the magnetic head 5 prepares to write the information on a plurality of tracks to be written (step S28). Then, while the magnetic card 2 is being conveyed by driving the motor 12, the write control unit 9 controls the magnetic head 5 to simultaneously write the write information on a plurality of tracks (step S29). When the writing is completed, the communication unit 8 notifies the control unit 21 that the writing is completed, and ends the processing.
[0035]
FIG. 9 is a diagram illustrating a temporal change in the write current, the circuit current consumption, and the current consumption of the magnetic card reader / writer 1 when the write information is information to be written into only one track. In FIG. 9, information is written to the magnetic card 2 by the F2F recording method. In the F2F recording method, the case where the magnetization reversal occurs on the magnetic stripe 2c within the section of the fixed period t is defined as logic “1”, and the case where it does not occur is defined as logic “0”. M0 is a timing at which the write control unit 9 controls the write current flowing to the magnetic head 5 at a constant period t. M1 is the timing at which the write control unit 9 controls the write current flowing through the magnetic head 5 to write the information of the logic "1", and is at the midpoint of the constant period t. “1” and “0” in (a) indicate write information to be written to one track to be written. Here, one track to be written is a first track T1. (B) shows a write current flowing through the core 5a (FIG. 2) of the magnetic head 5 to write the write information on the first track T1. Conventionally, information was written only on the first track T1 by merely passing such a write current having a pulse waveform. Therefore, the current consumed by the entire magnetic card reader / writer 1 was reduced as shown in FIG. If the power consumption changes in accordance with the information and the change in current consumption is acquired by a third party, the write information shown in FIG.
[0036]
On the other hand, in the procedure described with reference to FIG. 8, the write information is written to the first track T1 in a state where the noise is generated by the noise generator 16. Therefore, in the noise generation unit 16, the switch control circuit 19 controls the switching of the transistors TR1 to TR4 at the timing M1 at which the write control unit 9 controls the write current to write the information of logic “1”. Therefore, the circuit current consumption changes at a constant frequency as shown in (d) according to the timing M1, and the noise in the magnetic card reader / writer 1 changes as shown in (e) with the change in the circuit current consumption. At timing M1. When information is written to the first track T1 in a state where noise is generated as described above, the noise shown in (e) is superimposed on the current consumption shown in (c), and the current consumption becomes (f). The changes are complicated as shown.
[0037]
On the other hand, if the write information is information to be written on a plurality of tracks, different information is simultaneously written on the plurality of tracks T1 to T3, so that different waveforms are applied to the cores 5a to 5c of the magnetic head 5 as described with reference to FIG. Therefore, each time the polarity (+ and-) of each write current changes, the current consumption is affected and fluctuates, which complicates the change of the current consumption. Therefore, even if the change in the current consumption is acquired by a third party, it is possible to prevent the write information from leaking due to the change in the current consumption, regardless of the number of tracks T1 to T3 in which the information is written. As a result, the problem that information unique to the magnetic card 2 such as a credit card number and a bank account number is restored from the written information does not occur.
[0038]
In addition, the noise generation unit 16 generates noise at the timing M1 at which the write control unit 9 controls the write current to write the information of the logic “1”, so that the change in the consumption current in FIG. The information "0" cannot be read, and the leakage of the written information can be more reliably prevented.
[0039]
Further, when information is simultaneously written to a plurality of tracks T1 to T3, noise is not generated by the noise generating unit 16, so that the current consumption increases as in the above-mentioned Patent Document 1 and the temperature of the entire magnetic card reader / writer 1 becomes high. The heat does not cause the coils of the cores 5a to 5c of the magnetic head 5 to be disconnected or the magnetic card 2 in contact with the magnetic head 5 to be melted.
[0040]
In the above-described embodiment, the case where information is written or read on the magnetic card 2 in which three tracks T1 to T3 are formed on the magnetic stripe 2c is taken as an example. It is not limited to. In addition, a magnetic card having two or four or more tracks formed on a magnetic stripe may be used. Further, the magnetic recording medium in the present invention is not limited to a magnetic card, but may be a passbook provided with a magnetic recording unit used in a financial institution or the like, or a magnetic ticket used in a railway or the like.
[0041]
In the embodiment shown in FIG. 5, the write information is written on the track T1 to be written, and at the same time, the information originally recorded on the two tracks T2 and T3 not to be written is written back. Information originally recorded on one of the tracks T2 and T3 may be written back. Alternatively, dummy information may be stored in the memory 7 in advance, and when no information is recorded on a track that is not a write target, the dummy information may be read from the memory 7 and written on a track that is not a write target.
[0042]
In the embodiment shown in FIG. 4, the process of reading information from the magnetic card 2 and storing the information in the memory 7 (step S11) is executed before writing information is received from the information processing device 20 (step S13). This process may be performed between the time when the write information is received (step S13) and the time when the information of the track not to be written is prepared so as to be written (step S16). In this way, since the track to be written can be known from the received write information, the information of the track to be written is not read, and only the information of the track not to be written can be read. In addition, it is possible to store only information of a track that is not a writing target in the memory 7.
[0043]
In the embodiment shown in FIG. 9, the switch control circuit 19 controls the switching of the transistors TR1 to TR4 at a constant frequency so as to generate noise each time at the timing M1 at which the information of logic "1" is written. The transistors TR1 to TR4 may be switched and controlled so as to generate noise only once in several times. Further, the noise generation unit 16 generates a pulse waveform in which a plurality of frequencies are combined as shown in FIG. 10A, a pulse waveform with a random frequency as shown in FIG. The transistors TR <b> 1 to TR <b> 4 may be switched and controlled such that noise is generated based on the current consumption of the circuit. Further, the switching control may be performed such that noise is generated based on a circuit current consumption having a waveform such as a triangular wave shown in (d) or a sine wave shown in (e). That is, the switching control of the transistors TR1 to TR4 may be performed so as to generate noise at a predetermined timing and complicate the change in the current consumption of the entire magnetic card reader / writer 1.
[0044]
【The invention's effect】
According to the present invention, when information is written to one of a plurality of tracks of a magnetic recording medium, different information is simultaneously written to other tracks, or information is written in a state where noise is generated. Since the change in current consumption is complicated, it is possible to prevent the write information from leaking due to the change in current consumption.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a magnetic card reader / writer used in an information processing apparatus.
FIG. 2 is a diagram showing the outer shape of a magnetic card and the structure of a magnetic head.
FIG. 3 is a block diagram illustrating an electrical configuration of a magnetic card reader / writer.
FIG. 4 is a flowchart showing a write operation of the magnetic card reader / writer.
FIG. 5 is a diagram showing a temporal change of a write current and a consumption current.
FIG. 6 is a block diagram of another embodiment.
FIG. 7 is a diagram illustrating an example of a specific configuration of a noise generation unit according to another embodiment.
FIG. 8 is a flowchart illustrating a write operation according to another embodiment.
FIG. 9 is a diagram illustrating a temporal change in a write current, a circuit consumption current, and a consumption current according to another embodiment.
FIG. 10 is a waveform chart showing another example of the circuit consumption current in the noise generation unit.
FIG. 11 is a diagram showing a conventional example.
FIG. 12 is a diagram for explaining a problem of a conventional example.
[Explanation of symbols]
1 Magnetic card reader / writer
2 Magnetic card
5 Magnetic head
6 CPU
7 Memory
8 Communication section
9 Write control unit
10 Reading control unit
16 Noise generator
20 Information processing device
M1 Timing of writing information of logic "1"
T1 truck
T2 truck
T3 truck

Claims (7)

A magnetic head capable of simultaneously writing different information on a plurality of tracks provided on a magnetic recording medium,
Receiving means for receiving write information to be written to a magnetic recording medium from a higher-level device;
Determining means for determining whether or not the write information received by the receiving means is information to be written into only one track;
When the determination unit determines that the write information is not information to be written to only one track, the magnetic head is controlled to simultaneously write the write information to a plurality of tracks to be written. When it is determined that the information is information to be written to only one track, the magnetic head is controlled to write the write information to the track to be written, and at the same time, information different from the write information is written to the track not to be written. A magnetic information writing device, comprising: writing means for writing. The magnetic information writing device according to claim 1,
The magnetic head is capable of reading information from a plurality of tracks on a magnetic recording medium,
Before the writing unit performs writing of information, the reading unit that reads information from a plurality of tracks of a magnetic recording medium by controlling a magnetic head and stores the read information in a memory,
The magnetic information writing apparatus according to claim 1, wherein the writing unit writes information read from the track and stored in the memory as information different from the writing information. The magnetic information writing device according to claim 1 or 2,
The receiving means individually receives the write information from the host device for each of the tracks,
When the receiving unit receives write information for a plurality of tracks, the determination unit determines that the write information is not information to be written to only one track, and the receiving unit receives the write information for one track. In this case, it is determined that the write information is information to be written into only one track. A magnetic head capable of simultaneously writing different information on a plurality of tracks provided on a magnetic recording medium,
Noise generating means for generating noise by consuming a predetermined current that is equal to or greater than the write current flowing through the magnetic head;
Receiving means for receiving write information to be written to a magnetic recording medium from a higher-level device;
Determining means for determining whether or not the write information received by the receiving means is information to be written into only one track;
When the determination unit determines that the write information is not information to be written to only one track, the magnetic head is controlled to simultaneously write the write information to a plurality of tracks to be written. Writing means for controlling the magnetic head in a state where noise is generated by the noise generating means and writing the write information to a track to be written, when it is determined that the information is information to be written to only one track; , A magnetic information writing device. The magnetic information writing device according to claim 4,
A write current control unit that controls a write current flowing through the magnetic head in order to write the write information on the track by an F2F recording method;
The magnetic information writing apparatus according to claim 1, wherein the noise generation means generates noise at a timing at which the current control means controls the write current in order to write information of logic "1" of the F2F recording method. A magnetic information writing method for writing magnetic information by a magnetic head capable of simultaneously writing different information on a plurality of tracks provided on a magnetic recording medium,
After receiving write information to be written to the magnetic recording medium from the host device, it is determined whether the received write information is information to be written to only one track,
If it is determined that the write information is not information to be written to only one track, the magnetic head is controlled to simultaneously write the write information to a plurality of tracks to be written,
If it is determined that the write information is information to be written to only one track, the magnetic head is controlled to write the write information to the track to be written, and at the same time, information different from the write information is written to the track not to be written. Writing magnetic information. A magnetic information writing method for writing magnetic information by a magnetic head capable of simultaneously writing different information on a plurality of tracks provided on a magnetic recording medium,
After receiving write information to be written to the magnetic recording medium from the host device, it is determined whether the received write information is information to be written to only one track,
If it is determined that the write information is not information to be written to only one track, the magnetic head is controlled to simultaneously write the write information to a plurality of tracks to be written,
When it is determined that the write information is information to be written into only one track, the magnetic head generates noise by consuming a predetermined current that is substantially equal to or larger than the write current flowing through the magnetic head. And writing the write information on a track to be written.

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