JP4568510B2 - Communication control device and communication control method - Google Patents

Description

  The present invention radiates a carrier wave modulated by a logic signal transmitted from a control part of a machine as a radio wave, demodulates a signal received as a radio wave, generates a logic signal, and transmits it to a control part of the machine, etc. In particular, the present invention relates to a communication control device or the like in which a part where a logic signal flows is lengthened and a part where a carrier wave flows is shortened.

  In recent years, in an image forming apparatus such as a copying machine or a printer, a non-contact communication system including an RFID tag and a reader / writer is sometimes used to capture information of an exchange unit on the machine side in order to improve image quality. That is, an RFID tag including a first loop antenna and a non-volatile memory is mounted on an exchange unit or the like in the image forming apparatus, and the second loop antenna is placed at a position facing the RFID tag on the main body side of the image forming apparatus. A reader / writer including a transmission / reception circuit is provided. With this configuration, non-contact communication is performed between the RFID tag and the reader / writer, whereby information is exchanged between the exchange unit and the image forming apparatus main body. Specifically, the function of the machine can be improved by managing information such as toner consumption and remaining amount, and various information necessary for maintaining and improving image quality.

Information management using such a non-contact communication system is not limited to an image forming apparatus, but can be performed by other general machines. Conventionally, as a communication control apparatus mounted on a machine side, The thing of composition was adopted. Here, a case where there are three antennas will be described.
A first conventional example is shown in FIG. The first conventional example includes a CPU 60, non-contact communication circuits 70a to 70c, and antennas 80a to 80c. The non-contact communication circuits 70a to 70c output the carrier waves modulated by the logic signals sent from the CPU 60 to the antennas 80a to 80c, respectively, and demodulate the signals sent from the antennas 80a to 80c to the CPU 60. To communicate.
In this conventional example, the CPU 60 is mounted on the main board 91, and the non-contact communication circuit 70a and the antenna 80a, the non-contact communication circuit 70b and the antenna 80b, the non-contact communication circuit 70c and the antenna 80c are respectively an antenna board. 92a, 92b, 92c. The main board 91 and the antenna board 92a, the main board 91 and the antenna board 92b, and the main board 91 and the antenna board 92c are connected by harnesses 93a, 93b, and 93c, respectively.

However, the provision of the non-contact communication circuits 70 as many as the number of antennas as shown in FIG. 8 has the problem that the structure is complicated and the cost is increased, and thus several inventions have been made in the past ( For example, see Patent Documents 1 and 2.) A configuration common to these inventions is shown in FIG. 9 as a second conventional example. This second conventional example includes a non-contact communication circuit 70 in which the non-contact communication circuits 70a to 70c of FIG. 8 are combined into one, and an analog switch 71 for switching and selecting the antennas 80a to 80c. .
The CPU 60 is mounted on the main board 94, the non-contact communication circuit 70 and the analog switch 71 are mounted on the non-contact communication module board 95, and the antennas 80a, 80b, and 80c are connected to the antenna boards 96a, 96b, and 96c, respectively. It is installed. The main board 94 and the non-contact communication module board 95 are connected by a harness 97, and the non-contact communication module board 95 and the antenna board 96a, the non-contact communication module board 95 and the antenna board 96b, and the non-contact communication module. The board 95 and the antenna board 96c are connected by harnesses 98a, 98b, and 98c, respectively.
That is, in this conventional example, communication data is superposed on a carrier (carrier wave) by the non-contact communication circuit 70, and the signal can be oscillated from the antenna as it is and distributed to each antenna. For this reason, the signal of the extended portion (portions of the harnesses 98a to 98c) is an amplified and modulated carrier.

JP 2000-251027 (page 3, Fig. 1) JP 2001-052124 A (page 3-4, FIG. 1)

However, in the second conventional example, if only the antenna portion is extended, the portion where the modulated carrier flows becomes long. As a result, impedance matching is difficult, and there is radiation from other than the antenna. There is a problem that the communication distance and the layout are limited, which is disadvantageous to the conformity of the system.
Therefore, neither of the first and second conventional examples increases the degree of freedom of layout in the machine while reducing the cost.

  The present invention has been made to solve the technical problems as described above, and its object is to radiate a carrier wave modulated by a logic signal transmitted from a control part of a machine as a radio wave and In a communication control apparatus that demodulates a received signal to generate a logic signal and transmits the logic signal to a control part of the machine, the cost is reduced and the degree of layout freedom in the machine is increased.

Generally, when a contactless communication system mounted on a machine is electrically classified, (1) a main circuit for controlling the entire machine, (2) a contactless communication circuit (including a logic unit and a transmission / reception unit), ( 3) It can be divided into three antennas.
In the present invention, in order to achieve the above-described object, the part (2) is divided into an RF control unit (non-contact communication logic IC) and an RF transmission / reception unit (RF transmission / reception circuit), which are mounted on different substrates. . That is, the first communication control device of the present invention includes an RF control circuit board that generates a logic signal representing transmission data to the transponder, and a logic signal that is connected to the RF control circuit board and generated by the RF control circuit board. A signal line for transmission and an antenna substrate connected to the signal line and radiating a carrier wave modulated by a logic signal transmitted through the signal line as a radio wave are provided.
In addition, as many RF transmitters and antennas as necessary on the system are arranged for one RF controller. The main control circuit (1) and the RF control unit (part of (2)) may be separated from each other or mounted on the same substrate.

  The present invention can also be understood as a communication control method for emitting radio waves using the first substrate and the second substrate connected to the signal line. In that case, the communication control method of the present invention includes a step of generating a logic signal representing transmission data for the transponder by the first substrate, and a step of transmitting the generated logic signal to the second substrate through the signal line. And radiating a carrier wave modulated by the transmitted logic signal as an electric wave from an antenna provided on the second substrate.

  According to the present invention, a communication control device that radiates a carrier wave modulated by a logic signal transmitted from a control part of a machine as a radio wave, demodulates a signal received as the radio wave, generates a logic signal, and transmits the logic signal to the control part of the machine However, it is possible to increase the degree of freedom of layout in the machine while reducing the cost.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the following description, it is assumed that a non-contact communication system generally called RFID (Radio Frequency Identification) is used.
Here, RFID is a unit in which a first loop antenna is combined with a non-volatile memory capable of non-contact communication such as FeRAM (Ferroelectric Random Access Memory) and EEROM (Electronically Erasable Read Only Memory), and independent of this. And a unit in which the second loop antenna is connected to a transmission / reception circuit. When the first loop antenna and the second loop antenna are opposed to each other, an electromagnetic wave in which data is superimposed on a carrier wave radiated from the second loop antenna is nonvolatile via the first loop antenna. It is a system that propagates to the memory, the non-volatile memory receives power, and transmits and receives data. In general, a unit composed of a nonvolatile memory and a first loop antenna is called a transponder, and a unit composed of a second loop antenna and a transmission / reception circuit is called a reader / writer or a transmission / reception device. The frequency band used is generally 125 KHz or 13.56 MHz.

FIG. 1 shows the configuration of the present embodiment. This embodiment can also be applied to communication with any transponder (including cards and sheets processed and called IC cards and tags, as well as coins and cylinders). Below, the case where it applies to communication with an RFID tag is demonstrated. Here, a case where there are three antennas will be described.
The present embodiment includes a CPU (Central Processing Unit) 10, a non-contact communication logic IC 20, RF transmission / reception circuits 30a to 30c, and antennas 40a to 40c. The RF transmission / reception circuits 30a, 30b, and 30c are respectively And an oscillation circuit 31a, a modulation circuit 32a, a demodulation circuit 33a, an oscillation circuit 31b, a modulation circuit 32b, a demodulation circuit 33b, an oscillation circuit 31c, a modulation circuit 32c, and a demodulation circuit 33c. In this configuration, the CPU 10 and the non-contact communication logic IC 20, and the non-contact communication logic IC 20 and each circuit in the RF transmission / reception circuits 30 a to 30 c are connected by a signal line through which a logic signal flows, The modulation circuits 32a to 32c and the demodulation circuits 33a to 33c in the RF transmission / reception circuits 30a to 30c and the antennas 40a to 40c are connected by a signal line that transmits a carrier.
In the present embodiment, the extension portion is constituted by the signal line through which the logic signal flows, and the signal line for transmitting the carrier is constituted by a short length. Therefore, at least the non-contact communication logic IC 20 and the RF transceiver circuit 30 are separated. The RF transceiver circuit 30 and the antenna 40 are preferably mounted on the same substrate.

Here, each configuration shown in FIG. 1 will be described.
The CPU 10 controls the entire machine, and controls non-contact communication such as data transmission / reception and antenna selection as necessary.
The non-contact communication logic IC 20 has a function of issuing data and commands necessary for non-contact communication and selecting an antenna based on information from the CPU 10 or the like. The data received from the nonvolatile memory (tag) side is reconverted and sent to the main board side. Since this IC has no analog circuit portion, the function can be simplified and the cost can be reduced.
The oscillation circuits 31a to 31c in the RF transmission / reception circuits 30a to 30c generate carriers. The modulation circuits 32a to 32c superimpose signals received from the non-contact communication logic IC 20 on the carriers generated by the oscillation circuits 31a to 31c and send the signals to the antennas 40a to 40c. The demodulation circuits 33a to 33c demodulate the carriers received by the antennas 40a to 40c and send them to the non-contact communication logic IC 20.
The antennas 40a to 40c radiate signals transmitted from the RF transmission / reception circuits 30a to 30c as radio waves. Adjust the resonance frequency according to the frequency band to be used.

Next, a specific configuration example of the present embodiment will be described.
FIG. 2 shows a first configuration example of the present embodiment, in which the CPU 10 and the non-contact communication logic IC 20 are mounted on different substrates. That is, the CPU 10 is mounted on the main board 51, the non-contact communication logic IC 20 is mounted on the RF control circuit board 52, the RF transmission / reception circuit 30a and the antenna 40a, the RF transmission / reception circuit 30b and the antenna 40b, the RF transmission / reception circuit 30c and the antenna 40c. Are mounted on antenna substrates 53a, 53b, and 53c, respectively. Further, as a signal line for connecting the main board 51 and the RF control circuit board 52, for example, a harness 54 is used, and the RF control circuit board 52 and the antenna board 53a, the RF control circuit board 52, the antenna board 53b, and the RF control circuit are used. For example, harnesses 55a, 55b, and 55c are used as signal lines that connect the substrate 52 and the antenna substrate 53c, respectively. If the RF control circuit board 52 on which the contactless communication logic IC 20 is mounted is provided separately from the main board 51 as in the first configuration example shown in FIG. 2, the RF control circuit board 52, the antenna board 53, However, only one set is required for connection between the main board 51 and the RF control circuit board 52. For this reason, a rational layout is possible if it is separated from the main board and placed at a convenient position of the machine.

  FIG. 3 shows a second configuration example of the present embodiment, in which the CPU 10 and the non-contact communication logic IC 20 are packaged on the same substrate. That is, the CPU 10 and the non-contact communication logic IC 20 are mounted on the main board 56, and the RF transceiver circuit 30a and the antenna 40a, the RF transceiver circuit 30b and the antenna 40b, the RF transceiver circuit 30c and the antenna 40c are respectively connected to the antenna boards 57a and 57b. , 57c. For example, harnesses 58a, 58b, and 58c are used as signal lines that connect the main board 56 and the antenna board 57a, the main board 56 and the antenna board 57b, and the main board 56 and the antenna board 57c, respectively. Note that the number of antenna substrates 57 and the arrangement location can be determined according to the shape and function of the machine side to which the antenna substrate 57 is attached. However, the actual number of connections is limited to the number of ports of the contactless communication logic IC 20 or less.

  In this embodiment, since the contactless communication logic IC 20 and the RF transmission / reception circuit 30 are separated from each other, portions that are extended by a harness or the like (54, 55a to 55c in FIG. 2, 58a to 58c in FIG. 3). The three signals are transmission data, a signal for controlling ON / OFF of radio wave output, and reception data, all of which are unmodulated logic signals (however, in addition to these three signal lines, (There is a line for GND).

In the present embodiment, the RF transceiver circuit 30 and the antenna 40 are mounted on the antenna substrate, and each of the RF transceiver circuits 30 includes the oscillation circuit 31, so that a radio wave test can be performed with the antenna alone. Yes.
However, since the RF transceiver circuit 30 is normally connected to the non-contact communication logic IC 20, it does not operate unless operation information is transmitted from the non-contact communication logic IC 20. When there are a plurality of antennas, which antenna is operated is determined by a signal from the logic IC 20 for non-contact communication.

Furthermore, in the present embodiment, a plurality of I / O circuits (FIFO and the like) of the non-contact communication logic IC 20 are provided as necessary to enable simultaneous communication with the plurality of antennas 40.
In the above description, the number of antennas is three. However, the same configuration can be adopted in the case of one antenna, two antennas, and four or more antennas.

As described above, in the present embodiment, the portion of the modem that controls communication with the RFID tag is divided into the non-contact communication logic IC 20 and the RF transmission / reception circuit 30.
FIG. 4 shows only this part focusing on information exchange. 2 is a diagram in the case where the configuration shown in FIG. 2 is adopted. The non-contact communication logic IC 20 is mounted on the RF control circuit board 52, and the modulation circuit 32 and the demodulation circuit 33 are mounted on the antenna board 53. Has been. Further, the modem portion is divided into the non-contact communication logic IC 20 and the RF transmission / reception circuit 30, so that each has a different oscillator (oscillator A and oscillator B). As the oscillator A and the oscillator B, specifically, a crystal oscillator can be used, and this is indicated in the RF control circuit board 52 as “XTALI (crystal, input meaning)”. As shown.

When the contactless communication logic IC 20 transmits a transmission data signal to the antenna substrate 53 at 106 kbps, the modulation circuit 32 of the antenna substrate 53 performs ASK (Amplitude Shift Keying) modulation. Specifically, this received signal is superimposed on a 13.56 MHz carrier wave and transmitted to the RFID tag.
The response from the RFID tag (tag response) is a BPSK (Binary Phase Shift Keying) signal in units of 8 waves of 847 KHz subcarrier signal as shown in FIG. Further, the demodulation circuit 33 of the antenna substrate 53 demodulates the BPSK signal as it is into a digital signal and is non-contacted as a reception data signal A (a logic signal generated by demodulating the reception signal) as shown in FIG. Transmit to the communication logic IC 20.

The non-contact communication logic IC 20 takes in the reception data signal A at a reception rate of 106 kbps. Here, the oscillation frequency of the oscillator A and the oscillator B is 13.56 MHz. However, since an oscillation frequency deviation of about 200 ppm is allowed, there may be a difference between the oscillation frequency of the oscillator A and the oscillation frequency of the oscillator B. When the reception data signal A is received in a state where there is a deviation in the oscillation frequency in this way, “1” and “0” can be correctly recognized from the reception data signal A while the number of received pulses is small. If the number increases, there is a problem that “1” and “0” may be erroneously recognized.
Therefore, in the present embodiment, as shown in FIG. 6, a non-contact communication logic IC 20 is provided with a DPLL (Digital Phase Locked Loop) 21, and when receiving the received data signal A, errors are accumulated at a predetermined timing. Configured to reset.

Hereinafter, this error reset will be described in detail.
The tag response is defined in the format of FIG. When this tag response is received, it is divided by 1 etu (one bit time, in this case, 1/106 k second), and the waveform received in each divided period is “0” shown in FIG. Or “1” is recognized by determining whether the waveform represents “1” or “1”.
Here, in the tag response format, there is a period in which “0” and “1” are fixed. “Preamble”, “SOF”, start bit / stop bit of “data”, and “EOF” correspond to this.

The BPSK phase determination circuit 22 of the non-contact communication logic IC 20 receives a data signal received from the antenna substrate during a period in which “1” of the “preamble” is continuously received (period indicated by light shading in FIG. 7). A reference signal synchronized with A is generated and phase locked. Thereafter, the BPSK phase determination circuit 22 determines the subsequent correction timing at the timing when the first “0” of “SOF” is received. That is, if the reference signal of the DPLL 21 is fixed as it is, the frequency shift of the transmitter is accumulated and the phase change determination is easy to make an error. Therefore, the period known to be “1” (the dark network in FIG. 7). In the period indicated by multiplication), DPLL phase correction is performed to reset the error accumulation.
With such a configuration, the received data signal B (demodulated data signal) in which “0” and “1” are correctly recognized is finally passed to the CPU 10.
In the above description, the modulation circuit 32 performs ASK modulation. However, for example, other modulation methods such as FSK (Frequency Shift Keying) modulation may be employed. Although it is assumed that the tag response is BPSK-modulated, a phase determination error due to a deviation in oscillation frequency can be corrected by a similar method even when other PSK modulation is performed. .

Finally, the effect brought about by the communication control system in the present embodiment will be described.
(1) Resistant to external noise In the present embodiment, only control signals and data signals are exchanged at locations other than between the RF transceiver circuit 30 and the antenna 40. That is, a logic signal that is much slower than the carrier wave flows in a harness or the like that connects other than between the RF transceiver circuit 30 and the antenna 40. For this reason, it is not necessary to give special consideration to impedance matching in this portion. In addition, the risk of malfunction due to external noise can be reduced.
In the conventional technique, since the carrier wave generated in the non-contact communication circuit 70 is transmitted by a harness or the like, there is a concern about malfunction due to external noise.

(2) Noise radiation can be suppressed In this embodiment, since the RF transceiver circuit 30 and the antenna 40 are close to each other, unnecessary radiation at this portion can be prevented. In the conventional technique, this portion is long like a harness, and extra radiation is generated.

(3) There are few layout restrictions If there are a plurality of nonvolatile memories in one machine, it is necessary to arrange the same number of antenna substrates on which the RF transceiver circuit 30 and the antenna 40 are mounted. Since such an antenna board is designed so that the communication distance is 12 to 13 mm at the maximum, the mounting position, direction, angle, and the like are determined in accordance with the antenna distance. At that time, since a relatively low-speed logic signal flows between the antenna substrate and the RF control circuit substrate, it is easy to lengthen the harness or the like. Prolonging the part where the logic signal flows is advantageous because there are few secondary obstacles due to extension, and there are few restrictions on the layout.
In the conventional technology, when placing in a machine, the part where the modulated carrier (carrier wave) flows is lengthened, so there is a concern about radio wave radiation and waveform quality, and it is necessary to pay special attention to impedance matching. There were some problems.

(4) Easy noise test In this embodiment, each RF transceiver circuit 30 has an oscillation circuit 31. Therefore, the power is supplied to the antenna substrate, and a part of the circuit is pulled up and pulled down. But it can oscillate. For this reason, the radio wave test can be performed only with the antenna alone (module including the RF transceiver circuit 30), and the degree of freedom in use is increased. In other words, it is not necessary to take the test every time the configuration or combination changes. In addition, since only the RF transmission / reception circuit 30 and the antenna 40 are required for the test, there is no longer a plurality of objects to be measured as in the conventional technique. For this reason, the variation in the amount of radio wave radiation for each object to be evaluated in the radio wave test is reduced, and quality control is facilitated.

(5) Simultaneous communication is possible In this embodiment, by providing a plurality of I / O circuits (such as FIFO) of the non-contact communication logic IC 20 as necessary, communication can be performed simultaneously with a plurality of antennas 40. It was. In a system configuration in which a plurality of antennas 40 and non-volatile memories are combined, it is important that the machine side can know which non-volatile memory communicated via which antenna 40 during simultaneous communication. . In the present embodiment, since the antenna 40 has a function of selecting, the antenna 40 can be discriminated from the CPU 10 (non-contact communication logic IC 20) side, there is no problem in information management, and the efficiency is high.

(6) Good communication efficiency (power supply is not interrupted)
In the present embodiment, the non-contact communication logic IC 20 and the RF transmission / reception circuit 30 are connected by the three signal lines described above, and the RF transmission / reception circuit 30 transmits radio waves from the non-contact communication logic IC 20 side. You can decide whether to put it out or not. Further, an unmodulated carrier (carrier wave) can be continuously output as necessary. For this reason, unlike the case where the changeover switch is used, the power supply to the nonvolatile memory can be prevented from being interrupted even when it is not selected. Since the non-volatile memory is prevented from returning to the reset state due to the interruption of the power supply, when resuming the next data communication, the first process necessary for establishing the communication can be omitted, and the communication efficiency is good. The overall communication time can be shortened, or more information can be exchanged at the same time.

(7) CPU load can be reduced In this embodiment, when a command to transmit / receive data to / from the nonvolatile memory is transmitted from the main board to the RF control circuit board, non-contact communication on the RF control circuit board The logic IC 20 performs data conversion necessary for non-contact communication. Since data conversion is performed in this part, the load on the CPU 10 can be reduced.

It is the block diagram which showed the function structure of embodiment of this invention. It is the figure which showed the 1st structural example of embodiment of this invention. It is the figure which showed the 2nd structural example of embodiment of this invention. It is a block diagram which paid its attention to the exchange of information between RF control circuit board and antenna board of an embodiment of the invention. It is the figure which showed the waveform received by the antenna board in embodiment of this invention, and the waveform transmitted to an RF control circuit board from an antenna board. It is the block diagram which showed the internal structure of the logic IC for non-contact communication in embodiment of this invention. It is the figure which showed the format of the tag response received by the logic IC for non-contact communication in embodiment of this invention. It is the figure which showed the 1st prior art example. It is the figure which showed the 2nd prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... CPU, 20 ... Logic IC for non-contact communication, 21 ... DPLL, 22 ... BPSK phase determination circuit, 30 ... RF transmission / reception circuit, 31 ... Oscillation circuit, 32 ... Modulation circuit, 33 ... Demodulation circuit, 40 ... Antenna

Claims (6)

An RF control circuit board that generates a logic signal representing transmission data to the transponder and selects an antenna used for transmitting the logic signal;
A signal line connected to the RF control circuit board and transmitting the logic signal generated by the RF control circuit board;
A modulation circuit that is connected to the signal line and generates a carrier wave by modulating with the logic signal transmitted by the signal line, and a plurality of antenna boards that are mounted with one antenna that radiates the carrier wave as a radio wave ;
The antenna substrate is
A first oscillator that determines a timing for sending the generated logic signal to the signal line;
The RF control circuit board is
A second oscillator that determines the timing for extracting received data from the transmitted logic signal;
When receiving the PSK (Phase Shift Keying) modulated logic signal, the logic signal is caused by a difference in oscillation frequency between the first oscillator and the second oscillator at a timing according to the format of the received data. A communication control apparatus comprising: a PLL (Phase Locked Loop) circuit that corrects an error in extracting the received data from the receiver .   The communication control apparatus according to claim 1, wherein the antenna substrate includes an oscillation circuit that generates a carrier wave modulated by the logic signal.   The communication control apparatus according to claim 1, wherein the antenna substrate continuously radiates an unmodulated carrier wave according to an instruction from the RF control circuit substrate.   The communication control apparatus according to claim 1, wherein the RF control circuit board includes a plurality of input / output circuits. The antenna substrate demodulates a signal received as a radio wave from a transponder to generate a logic signal,
The signal line transmits the logic signal generated by the antenna board to the RF control circuit board,
The communication control apparatus according to claim 1, wherein the RF control circuit board extracts received data from the logic signal transmitted through the signal line. An image forming apparatus main body;
A unit attached to the image forming apparatus main body,
The unit includes a transponder having a memory storing information of the unit,
The image forming apparatus main body includes a communication control device that performs transmission and reception with respect to the transponder of the unit,
The communication control device includes:
An RF control circuit board for generating a logic signal representing transmission data for the transponder and selecting an antenna used for transmitting the logic signal;
A signal line connected to the RF control circuit board and transmitting the logic signal generated by the RF control circuit board;
A modulation circuit that is connected to the signal line and generates a carrier wave by modulating with the logic signal transmitted by the signal line, and a plurality of antenna boards that are mounted with one antenna that radiates the carrier wave as a radio wave;
The antenna substrate is
A first oscillator that determines a timing for sending the generated logic signal to the signal line;
The RF control circuit board is
A second oscillator that determines the timing for extracting received data from the transmitted logic signal;
When receiving the PSK (Phase Shift Keying) modulated logic signal, the logic signal is caused by a difference in oscillation frequency between the first oscillator and the second oscillator at a timing according to the format of the received data. A PLL (Phase Locked Loop) circuit for correcting an error in extracting the received data from
An image forming apparatus comprising:

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