JP5927108B2 - Signal demodulation circuit and transmission circuit - Google Patents

Description

  The present invention relates to a signal demodulation circuit and a transmission circuit, and more particularly to a technique for adjusting a resonance frequency used for communication.

  For example, in an image forming apparatus, a toner cartridge is detachably attached to a developing device, but a reader / writer device on the image forming apparatus main body side has a wireless tag provided on the toner cartridge at a predetermined resonance frequency. A communication system is employed in which cartridge information such as the type and amount of toner stored in the toner cartridge is acquired from the wireless tag. In addition, as shown in Patent Document 1 below, when a correct temperature control is not performed on a fresh food product to which a wireless tag is attached, the temperature fuse reacts and the inductance or capacitance of the resonance circuit of the wireless tag There has also been proposed a communication system in which the resonance frequency is intentionally changed from normal to abnormal by detecting the inappropriateness of temperature management.

JP 2005-157485 A

  In the case of the image forming apparatus described above, if the resonance circuit in the reader / writer device or the wireless tag is affected by the surrounding environment or the like and the resonance frequency of the reader / writer device and the wireless tag is shifted, there is a possibility that inconvenience occurs in communication. . For this reason, it is desirable to provide a mechanism that can adjust the resonance circuit to a desired resonance frequency with a simple configuration and corresponding to the surrounding environment. The communication system disclosed in Patent Document 1 changes the resonance frequency from normal to abnormal by changing the inductance and capacitance by the reaction of the thermal fuse in response to the temperature change. It cannot be adjusted to the frequency.

  The present invention has been made to solve the above problems, and has an object to make it possible to adjust a resonance circuit to a desired resonance frequency with a simple configuration in accordance with the surrounding environment and the like.

The invention according to the first aspect of the present invention is a signal demodulation circuit that demodulates a signal received from the transmission circuit side,
A capacitor unit for coupling a carrier wave subjected to amplitude modulation by a subcarrier wave from the transmission circuit;
A multiple loop composed of a plurality of conductive loops is formed in a pattern, and includes a coil portion that is connected in parallel to the capacitor portion and forms a parallel resonance circuit with the capacitor portion,
The coil portion is formed with an adjustment pattern that crosses the plurality of conductive loops and is connected to the respective conductive loops, and an inductance adjustment in which a connection portion with the adjustment pattern in each of the conductive loops can be cut It has a part.

The invention according to the fourth aspect of the present invention is a transmission circuit for transmitting a signal to a signal demodulation circuit,
A capacitor unit for coupling a carrier wave subjected to amplitude modulation by a sub-carrier wave;
A multiple loop composed of a plurality of conductive loops is formed in a pattern, and is connected in parallel to the capacitor unit, and includes a coil that forms a parallel resonance circuit with the capacitor unit,
The coil portion is formed with an adjustment pattern that crosses the plurality of conductive loops and is connected to the respective conductive loops, and an inductance adjustment in which a connection portion with the adjustment pattern in each of the conductive loops can be cut It has a part.

  According to these inventions, in the inductance adjusting part of the coil part, it is necessary among the plurality of conductive loops constituting the coil part by cutting each conductive loop at the connection part with the adjustment pattern as necessary. Only a number of loops corresponding to the number of windings can be connected to the capacitor unit. For this reason, since the inductance can be changed by changing the number of turns of the coil portion according to the surrounding environment or the like by the cutting operation, a parallel resonance circuit in which the capacitor portion and the coil portion are connected to a desired resonance Easy to adjust to frequency.

The invention according to the second aspect of the present invention is a signal demodulation circuit that demodulates a signal received from the transmission circuit side,
A capacitor unit for coupling a carrier wave subjected to amplitude modulation by a subcarrier wave from the transmission circuit;
A coil unit connected in parallel to the capacitor unit and forming a parallel resonance circuit with the capacitor unit;
The capacitor unit includes a plurality of capacitors connected in parallel with each other by a wiring pattern, and includes a capacitance adjusting unit in which a wiring pattern portion connecting each capacitor can be cut.

The invention according to a fifth aspect of the present invention is a transmission circuit for transmitting a signal to a signal demodulation circuit,
A capacitor unit for coupling a carrier wave subjected to amplitude modulation by a sub-carrier wave;
A coil that is connected in parallel to the capacitor unit and forms a parallel resonant circuit with the capacitor unit;
The capacitor unit includes a plurality of capacitors connected in parallel with each other by a wiring pattern, and includes a capacitance adjusting unit in which a wiring pattern portion connecting each capacitor can be cut.

  According to these inventions, in the capacitance adjustment unit included in the capacitor unit, by cutting the wiring pattern portion connecting the capacitors, the number of capacitors corresponding to the required capacitance among the plurality of capacitors constituting the capacitor unit. Only the capacitor can be connected to the coil section. For this reason, it is possible to change the capacitance by changing the number of capacitors in the capacitor unit according to the surrounding environment or the like by the cutting operation, so that the parallel resonance circuit in which the capacitor unit and the coil unit are connected to the desired resonance Easy to adjust to frequency.

The invention according to a third aspect of the present invention is the signal demodulating circuit according to the second aspect of the present invention , wherein the coil section is formed by patterning a multiple loop composed of a plurality of conductive loops. And an inductance adjustment section that is formed with an adjustment pattern that crosses the plurality of conductive loops and is connected to the respective conductive loops, and a connection portion with the adjustment pattern in each of the conductive loops can be cut. It is what you have.

Further, the invention according to a sixth aspect of the present invention is the transmission circuit according to the fifth aspect of the present invention , wherein the coil is formed by patterning a multiple loop composed of a plurality of conductive loops, and the coil portion is An adjustment pattern that crosses the plurality of conductive loops to connect to the conductive loops is formed, and has an inductance adjustment unit that can cut a connection portion of the conductive loops with the adjustment pattern. It is.

  According to these inventions, in the inductance adjustment section of the coil section, only a number of loops corresponding to the required number of turns among the plurality of conductive loops can be connected to the capacitor section, and in the capacitance adjustment section of the capacitor section. Since only a number of capacitors corresponding to the required capacitance among the plurality of capacitors can be connected to the coil unit, the capacitor unit and the coil unit are connected in parallel in a wider range corresponding to the surrounding environment. The resonance circuit can be adjusted to a desired resonance frequency.

  According to the present invention, it is possible to easily adjust a parallel resonance circuit in which a capacitor unit and a coil unit are connected to a desired resonance frequency corresponding to the surrounding environment and the like.

1 is a cross-sectional view schematically illustrating an internal configuration of a printer that is an example of an image forming apparatus including a signal demodulation circuit and a transmission circuit according to the present invention. It is sectional drawing which shows the detailed structure of a image development part. FIG. 3 is a partially enlarged view of a range indicated by a symbol A of a developing unit in FIG. 2. It is explanatory drawing which shows schematic structure of a communication system. It is a figure which shows the part of the coil part and capacitor | condenser part in a reader / writer part. It is a figure which shows the state which maximized the number of the conductive loops which make the multiple loop of a coil part. It is a figure which shows the state which reduced the number of the conductive loops which make the multiple loop of a coil part 1 turn from the maximum number of turns. It is a figure which shows the state which reduced the number of the conductive loops which make the multiple loop of a coil part 2 times from the maximum number of turns. It is a figure which shows the state which maximized the number of capacitors of the capacitor | condenser part.

  Hereinafter, a signal demodulation circuit and a transmission circuit according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing an internal configuration of a printer 1 as an example of an image forming apparatus including a signal demodulation circuit and a transmission circuit according to the present invention.

  The printer 1 includes a paper feed unit 8, an image forming unit 2, a transfer unit 9, a fixing unit 11, a paper discharge tray 12, and the like.

  The image forming unit 2 includes a photosensitive drum 3, a charging unit 4, an exposure unit 5, a developing unit 6, a cleaning unit 7, and the like.

  The photosensitive drum 3 is an image carrier on which a toner image is formed. The charging unit 4 uniformly charges the photosensitive drum 3. The exposure unit 5 exposes the circumferential surface of the uniformly charged photoreceptor drum 3 to form an electrostatic latent image. The developing unit 6 visualizes the formed electrostatic latent image to create a toner image. The toner image produced in this way is transferred onto the recording paper by a transfer unit 9 described in detail later. The cleaning unit 7 cleans the toner remaining on the surface of the photosensitive drum 3 after the transfer is completed.

  The transfer unit 9 includes a transfer roller 91, and the toner image formed on the photosensitive drum 3 is transferred to the recording paper conveyed from the conveyance path 83 in a state where the transfer roller 91 is pressed against the photosensitive drum 3. Transfer.

  The paper feed unit 8 includes a paper feed cassette 81, a pickup roller 82, a transport path 83, a transport roller 84, and the like. The recording paper loaded on the paper feed cassette 81 is transferred to the image forming unit 2 and the transfer unit 9 side (downstream). Paper).

  The fixing unit 11 is provided on the downstream side of the image forming unit 2 and the transfer unit 9, and includes a heat roller 11a and a pressure roller 11b. The fixing unit 11 performs fixing processing of the toner image transferred to the recording paper.

  On the further downstream side of the fixing unit 11, a conveyance roller 86, a discharge roller 87, a conveyance path 85, and the like are provided, and the recording paper subjected to fixing processing by the fixing unit 11 further passes through the conveyance path 85 by these rollers. The paper is conveyed downstream and discharged to the paper discharge tray 12 at the top of the printer 1.

  FIG. 2 is a cross-sectional view showing a detailed configuration of the developing unit 6. The developing unit 6 includes a toner cartridge 61 formed of a container (container) for storing toner (developer), and a developing unit 62 including a developing roller 621 and the like. The pumping roller 622 and the supply roller 623 are driven to rotate. Thus, the toner in the toner cartridge 61 is supplied to the agitating unit, and the toner is supplied to the developing roller 621 by the rotational drive of the agitating roller 611 (agitation screw). A developing sleeve 6211 is provided on the outer peripheral portion of the developing roller 621, and a developing bias is applied to the developing sleeve 6211, and the toner charged positively by the agitating portion is used as the photosensitive drum 3 (FIG. 1). It is adsorbed on the exposed portion of the surface (the portion of the electrostatic latent image from which static electricity has been removed by exposure).

  The developing unit 6 is configured such that the toner cartridge 61 can be detachably attached to the developing unit 62.

  FIG. 3 is a partially enlarged view of a range indicated by a symbol A of the developing unit 6 in FIG. The configuration of the lower part of the mounted toner cartridge 61 is shown in detail.

  A wireless tag 101 is attached to one side wall portion of the toner cartridge 61. A reader / writer unit 102 is attached to one side wall of the developing unit 62. The communication system 100 includes the wireless tag 101 and the reader / writer unit 102, and performs RF-ID communication. When the toner cartridge 61 is mounted, the wireless tag 101 and the reader / writer unit 102 face each other with a predetermined distance (for example, about 5 mm).

  The wireless tag (transmission circuit) 101 performs wireless communication (communication) with the reader / writer unit 102. The wireless tag 101 includes a semiconductor chip (wireless IC chip) that can transmit and receive data using electromagnetic waves, generates electromotive force by electromagnetic waves from the reader / writer unit 102 (based on the principle of electromagnetic induction), and The circuit is driven by electric power, and the reader / writer unit 102 and control data (identification code) are exchanged.

  The reader / writer unit (signal demodulation circuit) 102 performs radio communication with the wireless tag 101 by outputting an electromagnetic wave having a predetermined frequency (for example, a resonance frequency of 13.56 MHz) with a predetermined communication output.

  As will be described in detail later, the wireless tag 101 and the reader / writer unit 102 can change the communication frequency.

  FIG. 4 is an explanatory diagram showing a schematic configuration of the communication system 100.

  The wireless tag 101 includes a memory 1011, a capacitor unit 1012, and a coil unit 1013.

  The memory 1011 is a memory in which information unique to the toner cartridge, for example, information such as a toner cartridge serial number, a model number, the number of times the toner cartridge is used, a characteristic (type) of toner in the container, and a remaining toner amount is stored. The reader / writer unit 102 reads the information stored in the toner cartridge from the wireless tag 101 by communication.

  The coil unit 1013 is an antenna including a coil and configured as a loop antenna. Wireless communication with the reader / writer unit 102 is performed via the coil unit 1013.

  The capacitor unit 1012 connected in parallel to the coil unit 1013 includes a capacitor, and constitutes a parallel resonance circuit 101f together with the coil unit 1013 unit. The parallel resonance circuit 101f functions as a filter that uses the input / output signal from the coil portion 1013 as a signal of the resonance frequency of the parallel resonance circuit 101f.

  The reader / writer unit 102 includes a coil unit 1021, a capacitor unit 1022, and a filter circuit 1023.

  The coil unit 1021 is an antenna including a coil having a configuration described later and configured as a loop antenna. Wireless communication with the wireless tag 101 is performed via the coil unit 1021.

  The coil unit 1021 has a chip capacitor C and capacitors C1, C2, and C3 connected in parallel to each other by a pattern formed on the substrate. The capacitor unit 1022 is connected in parallel to the coil unit 1021 to form a parallel resonance circuit 102f. That is, the parallel resonant circuit 102f is formed by the inductance of the coil portion 1021 and the combined capacitance of the chip capacitor C and the capacitors C1, C2, and C3. The parallel resonance circuit 102f functions as a filter that uses the input / output signal from the coil unit 1021 as a signal of the resonance frequency of the parallel resonance circuit 101f.

  The filter circuit 1023 detects the communication wave that has been converted to the resonance frequency signal by the parallel resonance circuit 102f, and further extracts a predetermined frequency component from the detected communication wave. Further, the filter circuit 1023 converts the communication wave after the extraction process into a digital code. This digital code is sent to a control circuit (not shown), and the control circuit extracts information (reception data for the reader / writer unit 102) that is to be transmitted by the wireless tag 101.

  The filter circuit 1023 generates a modulated wave based on the digital code converted by the control circuit. The generated modulated wave is converted into a communication wave having the resonance frequency by the parallel resonance circuit 102f, and is radiated from the coil unit 1021 to the wireless tag 101 by electromagnetic waves.

  Next, the configuration of the coil unit 1021 and the capacitor unit 1022 of the reader / writer unit 102 will be described. FIG. 5 is a diagram illustrating portions of the coil unit 1021 and the capacitor unit 1022 in the reader / writer unit 102.

  The coil unit 1021 includes a plurality of conductive loops Lo1, Lo2, and Lo3. In the initial state, the coil portion 1021 is a multiple loop Lo in which a plurality of conductive loops Lo1, Lo2, Lo3 are connected to one. The multiple loop Lo is patterned on the substrate as one loop by connecting a plurality of conductive loops. As shown in FIG. 5, the coil portion 1021 including the multiple loop Lo is connected in parallel to the capacitor portion 1022.

  The plurality of conductive loops Lo1, Lo2, Lo3 are formed with an adjustment pattern P1 that crosses the plurality of conductive loops Lo1, Lo2, Lo3 and connects to each of the conductive loops Lo1, Lo2, Lo3. Has been. Each conductive loop Lo1, Lo2, Lo3 can be cut at a portion connected to the adjustment pattern P1. The adjustment pattern P1 and each conductive loop portion formed so as to be cuttable (a connection portion with the adjustment pattern P1 in each conductive loop) constitutes an inductance adjustment portion 1025.

  As described above, the capacitor unit 1022 includes the chip capacitor C and the capacitors C1, C2, and C3 connected in parallel to each other. The printed wiring P2 on the substrate that connects the capacitors C1, C2, and C3 to each other can be cut. The printed wiring P2 includes a printed wiring P21 that connects the chip capacitor C and the capacitor C1, a printed wiring P22 that connects the capacitor C1 and the capacitor C2, and a printed wiring P23 that connects the capacitor C2 and the capacitor C3. Each of the wirings P21, P22, and P23 can be cut. The printed wiring P2 that can be cut off forms a capacitance adjustment unit 1026.

  In addition, the wiring part shown with a continuous line in FIG. 5 is formed on the substrate surface, and the wiring shown with a broken line is formed on the back surface of the substrate. These wirings formed on the front and back surfaces of the substrate are connected to each other on the front and back surfaces at a connection point Pt in FIG.

  Next, the inductance adjustment in the inductance adjustment unit 1025 of the coil unit 1021 will be described. FIG. 6 is a diagram showing a state in which the number of conductive loops forming the multiple loop Lo of the coil portion 1021 is maximized. FIG. 7 is a diagram showing a state in which the number of conductive loops forming the multiple loop Lo of the coil portion 1021 is reduced by one from the maximum number of turns. FIG. 8 is a diagram illustrating a state in which the number of conductive loops forming the multiple loop Lo of the coil portion 1021 is subtracted by 2 from the maximum number of turns.

  As shown in FIG. 5, in the initial state, the ends of the conductive loops Lo1, Lo2, Lo3 are short-circuited to form a single loop.

  When the reader / writer unit 102 is used with the maximum number of conductive loops, the adjustment pattern P1 is cut at portions P12 and P13 shown in FIG. That is, the state in which the conductive loops Lo1, Lo2, Lo3 are connected to each other by the adjustment pattern P1 is released, and as shown in FIG. 6, both ends of one loop made up of the conductive loops Lo1, Lo2, Lo3 are connected to the capacitor portion 1022. The coil portion 1021 composed of these conductive loops Lo1, Lo2, and Lo3 is connected to the capacitor portion 1022 in parallel.

  Further, when the reader / writer unit 102 is used with the number of conductive loops reduced by 1 from the maximum number of windings, the adjustment pattern P1 is cut at the P13 portion shown in FIG. Further, the conductive loop Lo1 portion connected to the adjustment pattern P1 is cut. That is, as shown in FIG. 7, the conductive loops Lo2 and Lo3 excluding the conductive loop Lo1 form one loop, and both ends of one loop formed by the conductive loops Lo2 and Lo3 are connected to the wiring of the capacitor portion 1022. Thus, the coil portion 1021 composed of the conductive loops Lo2 and Lo3 is connected to the capacitor portion 1022 in parallel. The conductive loop Lo1 in which the connection portion with the adjustment pattern P1 is cut becomes a loop in which both ends are opened.

  Further, when the reader / writer unit 102 is used in a state where the number of conductive loops is reduced from the maximum number of turns, the conductive loop Lo1 connected to the adjustment pattern P1 is cut, and further the adjustment pattern P1 The conductive loop Lo2 connected to is cut off. The adjustment pattern P1 is in an initial state. That is, as shown in FIG. 8, the conductive loop Lo3 excluding the conductive loops Lo1 and Lo2 constitutes one loop, and both ends of one loop formed by the conductive loop Lo3 are connected to the wiring of the capacitor portion 1022, The coil part 1021 formed of these conductive loops Lo3 is connected to the capacitor part 1022 in parallel. The conductive loops Lo1 and Lo2 in which the connection portion with the adjustment pattern P1 is cut are loops whose both ends are open.

  That is, in each of the above states, when the number of turns of the coil portion 1021 is reduced, the conductive loops Lo1 and Lo2 are connected to the adjustment pattern P1 by cutting the main points of the adjustment pattern P1 and the conductive loops Lo1 and Lo2. Or make an adjustment to cancel. As a result, the conductive loops Lo1 and Lo2 are not formed with a short-circuit winding and do not form a loop through which the magnetic flux of electromagnetic coupling penetrates, and are opened so as not to affect the resonance frequency. As described above, by changing the inductance by changing the number of turns of the coil portion 1021, the resonance frequency that resonates with the capacitance of the chip capacitor C + capacitor C1 + capacitor C2 + capacitor C3 can be varied. The resonant circuit can be easily adjusted to a desired resonant frequency.

  Next, capacitance adjustment by the capacitance adjustment unit 1026 of the capacitor unit 1022 will be described. FIG. 9 is a diagram illustrating a state where the number of capacitors in the capacitor unit 1022 is maximized. In FIG. 9, the illustration of the inductance adjusting unit 1025 is omitted for ease of explanation.

  When the reader / writer unit 102 is used with the maximum number of capacitors in the capacitor unit 1022, as shown in FIG. 9, the printed wirings P21, P22, and P23 on the substrate connecting the capacitors are not cut, and the chip capacitor C Assume that the capacitor C1, the capacitor C2, and the capacitor C3 are connected in parallel to each other.

  Further, when the reader / writer unit 102 is used with the number of capacitors reduced by one from the maximum number, the printed wiring P23 shown in FIG. 9 is cut so that the capacitor C3 is disconnected from other capacitors, and the chip capacitor C The capacitor C1 and the capacitor C2 are connected in parallel to each other.

  When the reader / writer unit 102 is used with the number of capacitors reduced by two from the maximum number, the printed wiring P22 shown in FIG. 9 is cut so that the capacitors C2 and C3 are separated from the other capacitors, It is assumed that the capacitor C and the capacitor C1 are connected in parallel to each other.

  Further, when the reader / writer unit 102 is used with the capacitor 1022 as the chip capacitor C only, the printed wiring P21 shown in FIG. 9 is cut so that the capacitors C1, C2 and C3 are separated from the other capacitors. The chip capacitor C constitutes the capacitor unit 1022, and only the chip capacitor C is connected to the coil unit 1021 in parallel.

  That is, in the pattern example described with reference to FIG. 5, four types of capacitance can be switched for the capacitor unit 1022.

  Although not specifically illustrated, as described above, the adjustment pattern P1 and the conductive loops Lo1, Lo2, Lo3 (connection portions with the adjustment pattern P1) of the inductance adjustment unit 1025 and the capacitance adjustment unit It is possible to adjust both the inductance of the coil portion 1021 and the capacitance of the capacitor portion 1022 by adjusting the degree of cutting with respect to the printed wiring P2 of 1026. Thereby, the parallel resonance circuit in which the capacitor portion and the coil portion are connected can be adjusted to a desired resonance frequency in a wider range corresponding to the surrounding environment.

  As described above, when the inductance is changed by changing the number of turns of the coil unit 1021 and the combined capacitance of the capacitors C, C1, C2, and C3 of the capacitor unit 1022 is adjusted to resonate, the number of turns of the coil unit 1021 is reduced, and the capacitor unit If the combined capacitance of 1022 is increased, the Q value, which is a value representing the resonance peak, can be lowered to achieve a wider pass frequency.

  That is, in this embodiment, since both the inductance of the coil unit 1021 and the capacitance of the capacitor unit 1022 can be adjusted, the resonance frequency and the Q value can be set to desired values.

  For example, when the toner in the toner cartridge 61 of the printer 1 is close to the antenna of the communication system 100, the toner affects the antenna as if it acts as a core in the electromagnetic coupling transformer. Even in this case, according to the communication system 100 according to the present embodiment, the communication between the toner in the toner cartridge 61 and the communication system 100 for each model of the printer by adjusting the inductance of the coil unit 1021 and the capacitance of the capacitor unit 1022 described above. The resonance frequency and the Q value can be adjusted to desired values in accordance with the distance to the antenna, etc., so that the substrate on which the communication system 100 is provided can be shared, and the cost of the communication system 100 can be reduced. It becomes possible.

  Note that the adjustment of the inductance of the coil unit 1021 and the capacitance of the capacitor unit 1022 is performed by connecting the multi-loop Lo (conductive loops Lo1, Lo2, Lo3 in the initial state shown in FIG. 9) and the reader / writer unit 102 in the initial state shown in FIG. 9 (in which the chip capacitor C and the capacitors C1, C2, and C3 are connected in parallel with each other), The inductance adjustment unit 1025 adjusts the inductance, and after the resonance frequency is measured in the adjustment process, the capacitance adjustment unit 1026 of the capacitor unit 1022 finely adjusts the capacitance. Since the adjustment for reducing the connected capacitors C1, C2, and C3 in the capacitance adjustment unit 1026 is to increase the resonance frequency, the above-mentioned adjustment is preferably set lower than the desired resonance frequency.

  Further, the wireless tag 101 also has a parallel resonance circuit including a coil portion 1013 and a capacitor portion 1012 having the same configuration as that described with reference to FIGS. Therefore, the resonance frequency can be adjusted also in the wireless tag 101 in the same manner as described with reference to FIGS.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. For example, in the above-described embodiment, both the wireless tag 101 and the reader / writer unit 102 of the communication system 100 are configured to be able to adjust the inductance and capacitance described above. The inductance / capacitance adjustment mechanism may be provided in only one of the reader / writer units 102.

  Furthermore, the wireless tag 101 and the reader / writer unit 102 do not have to have both the inductance adjustment mechanism and the capacitance adjustment mechanism, and may include only one of the adjustment mechanisms. .

  In addition, the number of turns of the coil unit 1021 and the number of capacitors of the capacitor unit 1022 shown in the above embodiment are merely examples, and the number of turns of the coil unit 1021 and the number of capacitors of the capacitor unit 1022 are not limited to the above.

  In the above embodiment, the communication system 100 is applied to an image forming apparatus using the printer 1 as an example. However, the communication system 100 can be widely applied to electrical devices other than the image forming apparatus. .

DESCRIPTION OF SYMBOLS 1 Printer 61 Toner cartridge 62 Developing unit 100 Communication system 101 Wireless tag 1011 Memory 1012 Capacitor part 1013 Coil part 101f Parallel resonance circuit 102 Writer part 1021 Coil part 1022 Capacitor part 1023 Filter circuit 1025 Inductance adjustment part 1026 Capacitance adjustment part 102f Parallel resonance circuit
C chip capacitor
C1, C2, C3 capacitors
Lo multiple loop
Lo1, Lo2, Lo3 conductive loop
P1 adjustment pattern
P2 printed wiring
P21, P22, P23 Printed wiring
Pt connection point

Claims (4)

A signal demodulation circuit that demodulates a signal received from the transmission circuit side,
A capacitor unit for coupling a carrier wave subjected to amplitude modulation by a subcarrier wave from the transmission circuit;
A multiple loop composed of a plurality of conductive loops is formed in a pattern, and includes a coil portion that is connected in parallel to the capacitor portion and forms a parallel resonance circuit with the capacitor portion,
The coil portion is formed with an adjustment pattern that crosses the plurality of conductive loops and is connected to the respective conductive loops, and an inductance adjustment in which a connection portion with the adjustment pattern in each of the conductive loops can be cut Department have a,
When the connection with the adjustment pattern is cut and the number of the plurality of conductive loops is reduced from the maximum number of turns by adjusting the inductance in the inductance adjustment unit, the adjustment among the plurality of conductive loops is performed. A signal demodulating circuit in which both ends of a conductive loop having a connection portion with a pattern for use are opened . A signal demodulation circuit that demodulates a signal received from the transmission circuit side,
A capacitor unit for coupling a carrier wave subjected to amplitude modulation by a subcarrier wave from the transmission circuit;
A coil unit connected in parallel to the capacitor unit and forming a parallel resonance circuit with the capacitor unit;
The capacitor unit includes a plurality of capacitors connected in parallel with each other by a wiring pattern, and includes a capacitance adjusting unit that can cut a wiring pattern part that connects each capacitor,
The coil portion is formed by patterning a multiple loop composed of a plurality of conductive loops, and the coil portion is formed with an adjustment pattern that crosses the plurality of conductive loops and is connected to the conductive loops. The connection portion with the adjustment pattern in each conductive loop has an inductance adjustment portion that can be cut,
When the connection with the adjustment pattern is cut and the number of the plurality of conductive loops is reduced from the maximum number of turns by adjusting the inductance in the inductance adjustment unit, the adjustment among the plurality of conductive loops is performed. A signal demodulating circuit in which both ends of a conductive loop having a connection portion with a pattern for use are opened . A transmission circuit for transmitting a signal to a signal demodulation circuit,
A capacitor unit for coupling a carrier wave subjected to amplitude modulation by a sub-carrier wave;
A multiple loop composed of a plurality of conductive loops is formed in a pattern, and is connected in parallel to the capacitor unit, and includes a coil that forms a parallel resonance circuit with the capacitor unit,
The coil portion is formed with an adjustment pattern that crosses the plurality of conductive loops and is connected to the respective conductive loops, and an inductance adjustment in which a connection portion with the adjustment pattern in each of the conductive loops can be cut Department have a,
When the connection with the adjustment pattern is cut and the number of the plurality of conductive loops is reduced from the maximum number of turns by adjusting the inductance in the inductance adjustment unit, the adjustment among the plurality of conductive loops is performed. A transmission circuit in which both ends of a conductive loop in which a connection portion with a pattern for use is cut are opened . A transmission circuit for transmitting a signal to a signal demodulation circuit,
A capacitor unit for coupling a carrier wave subjected to amplitude modulation by a sub-carrier wave;
A coil that is connected in parallel to the capacitor unit and forms a parallel resonant circuit with the capacitor unit;
The capacitor unit includes a plurality of capacitors connected in parallel with each other by a wiring pattern, and includes a capacitance adjusting unit that can cut a wiring pattern part that connects each capacitor,
The coil is formed by patterning multiple loops composed of a plurality of conductive loops, and the coil portion is formed with an adjustment pattern that crosses the plurality of conductive loops and is connected to the conductive loops. The connection portion with the adjustment pattern in the conductive loop has an inductance adjustment portion that can be cut,
When the connection with the adjustment pattern is cut and the number of the plurality of conductive loops is reduced from the maximum number of turns by adjusting the inductance in the inductance adjustment unit, the adjustment among the plurality of conductive loops is performed. A transmission circuit in which both ends of a conductive loop in which a connection portion with a pattern for use is cut are opened .