JP2008078965A - Non-contact communication system, non-contact communication method, and image forming device using non-contact communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply provide a non-contact communication system that allows to execute stable communications corresponding to a communication distance between an IC tag and a reader/writer, a non-contact communication method, and an image forming device using the non-contact communication system. <P>SOLUTION: The non-contact communication system is provided with the reader/writer 20, which executes non-contact communications by a prescribed communication carrier wave, the IC tag 10, whose resonance frequency is set to a first resonance frequency R<SB>1</SB>higher than a transmission frequency of the reader/writer 20, and a resonance-frequency reduction means that reduces the resonance frequency of the IC tag 10 from the first resonance frequency R<SB>1</SB>to a second resonance frequency R<SB>2</SB>almost equal to the transmission frequency of the reader/writer 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a non-contact communication system and a non-contact communication method, and more particularly to improvement of a non-contact communication system and a non-contact communication method applicable to an image forming apparatus.

JP 2003-179526 A

  In recent years, a non-contact IC tag (also referred to as an RFID (Radio Frequency IDentification) tag) that operates using power obtained from a received high-frequency signal as a power source has been used as a non-contact type information storage medium. Supply of power to the non-contact IC tag and reading / writing of information are performed by a reader / writer via a wireless space.

  In such a non-contact communication system, when expanding the communication range between the IC tag and the reader / writer, (1) the magnetic field generated from the reader / writer antenna is increased. (2) The resonance frequency of the IC tag is adjusted to increase the strength of the return signal from the IC tag. (3) There is a method such as adding an auxiliary antenna sheet (see, for example, Patent Document 1).

  Here, Patent Document 1 discloses a non-contact communication system that enables vertical communication between an IC tag and a reader / writer using an auxiliary antenna sheet.

  In general, in such a contactless communication system, in contactless communication (RFID) using a batteryless IC tag, the IC tag uses a communication carrier wave (hereinafter also referred to as a carrier wave) transmitted from an antenna of a reader / writer as power. Therefore, the closer the resonance frequency of the IC tag is to the frequency of the carrier wave, the better the reception sensitivity and the operation of the IC tag is possible even with a small magnetic field strength. However, in order for the reader / writer to reliably receive the reply signal from the IC tag, for example, when the communication distance is about 10 cm, it is not sufficient to increase the magnetic field generated from the reader / writer antenna. It is necessary to adjust the resonance frequency of the tag to increase the strength of the return signal from the IC tag.

  By the way, when the resonance frequency of the IC tag is adjusted as described above and the strength of the return signal from the IC tag is increased, the reception sensitivity of the IC tag is lowered, and the minimum magnetic field strength (required for the operation of the IC tag) Hereinafter, since the minimum operating magnetic field is deteriorated (more magnetic field is required), an IC tag having a higher resonance frequency and a small antenna whose antenna output is not so high (for example, the Japan Radio Law's weak radio) When combined with a station or high-frequency equipment), stable communication may occur.

  Specifically, in proximity communication at a distance of about 1 cm, if the IC tag has obtained the minimum operating magnetic field necessary for operation, the return signal is generally strong enough because both are close to each other. Communication errors often occur due to insufficient magnetic field strength (antenna power) on the reader / writer side. On the other hand, in remote communication at a distance of about 10 cm, even if the IC tag obtains a minimum operating magnetic field, the reader / writer cannot receive a reply signal from the IC tag (due to insufficient strength of the reply signal), resulting in a communication error. Many.

  In particular, in the case of reader / writers using small antennas, the antenna output is often limited to the last minute in order to make it easy to obtain approval of the radio law of each country on the assumption that it will be used in various countries around the world. When non-contact communication is performed by combining such a small antenna and an IC tag, deterioration (increase) of the minimum operating magnetic field of the IC tag tends to immediately lead to instability of non-contact communication.

  Accordingly, the present invention has been made in view of the above-described problems of the prior art, and is a non-contact communication system and non-contact communication capable of stable communication according to the communication distance between the IC tag and the reader / writer. It is an object of the present invention to simply provide a communication method and an image forming apparatus using the communication method.

  In order to achieve the above object, a non-contact communication system according to the present invention includes a reader / writer that performs non-contact communication using a predetermined communication carrier wave, and a first resonance whose resonance frequency is higher than a transmission frequency of the reader / writer. An IC tag set to a frequency and, in a predetermined case, resonance frequency reduction means for reducing the resonance frequency of the IC tag from the first resonance frequency to a second resonance frequency substantially equal to the transmission frequency of the reader / writer Are provided.

  In general, from the viewpoint of improving the minimum operating magnetic field of the IC tag and realizing stable non-contact communication, it is desirable to set the resonance frequency of the IC tag to be equal to the transmission frequency of the reader / writer. However, when the communication distance between the IC tag and the reader / writer exceeds a predetermined distance (for example, 1 cm), the resonance frequency of the IC tag is shifted higher than the transmission frequency of the reader / writer, It has been found that increasing the strength of the return signal can contribute to the expansion of the maximum communication distance, that is, the realization of more stable non-contact communication.

  Therefore, in the non-contact communication system according to the present invention, when an IC tag whose resonance frequency is set in advance higher than the transmission frequency of the reader / writer is used and the communication distance with the IC tag exceeds a predetermined distance. In addition to increasing the strength of the reply signal from the IC tag, for non-contact communication within a predetermined distance, the resonance frequency reducing means reduces the resonance frequency of the IC tag to be substantially equal to the transmission frequency of the reader / writer. In this way, the minimum operating magnetic field is improved, thereby enabling optimal non-contact communication according to the communication distance.

  Further, the resonance frequency reducing means includes an auxiliary antenna that reduces the resonance frequency of the IC tag substantially equal to the transmission frequency when the communication distance between the reader / writer and the IC tag is a predetermined distance or less. It can comprise by opposingly arranging.

  When configured in this way, in the case of proximity communication, the resonance frequency of the IC tag is reduced to improve its minimum operating magnetic field, thereby contributing to stabilization of non-contact communication. Can be easily realized.

  Further, the first resonance frequency may be set higher than the transmission frequency of the reader / writer by about the frequency of the return signal from the IC tag to the reader / writer.

  In this case, since the first resonance frequency is set to be higher than the transmission frequency of the reader / writer by the frequency of the response signal from the IC tag to the reader / writer, the response strength from the IC tag to the reader / writer is set. Can be optimally increased.

  An image forming apparatus according to the present invention includes the non-contact communication system and image forming means for forming a predetermined image on a recording medium, and the reader / writer is fixedly installed in the apparatus housing, and the IC tag Is provided on a replacement part that can be attached to and detached from the apparatus casing, and in the mounted state of the replacement part, the IC tag is arranged to face the reader / writer, and the auxiliary antenna is connected to the replacement part. The auxiliary antenna is provided so as to be detachable with respect to a component, and is disposed so as to face the reader / writer with the IC tag sandwiched in the mounted state. In a state in which contactless communication with the IC tag is performed without using the antenna and the replacement part is attached to the apparatus housing, the IC tag and the reader are connected through the auxiliary antenna. It is characterized in that perform non-contact communication with the writer.

  In the image forming apparatus according to the present invention configured as described above, in a state where the replacement part is removed from the image forming apparatus, for example, in the shipping stage in the factory / warehouse, the image forming apparatus is provided in the factory / warehouse without using the auxiliary antenna. In addition, since a large antenna having a large output can be used to read / write an IC tag provided on a replacement part immediately before shipment, it is possible to reduce the inventory of the replacement part and optimize the inventory.

  On the other hand, in a state where the replacement part is attached to the image forming apparatus, the resonance frequency of the IC tag is made equal to the transmission frequency of the reader / writer by performing non-contact communication with a reader / writer fixed in the apparatus via the auxiliary antenna. The minimum operating magnetic field is reduced to a certain extent, thereby preventing the occurrence of communication errors in near field communication, enabling accurate reading / writing of information necessary for ensuring image quality, and the device The degree of freedom of device layout in the housing can be increased.

  In the non-contact communication method according to the present invention, the reader / writer that performs non-contact communication using a predetermined communication carrier wave and the resonance frequency thereof are set to a first resonance frequency that is higher than the transmission frequency of the reader / writer. When an IC tag is used and a communication distance with the IC tag is within a predetermined distance, an auxiliary antenna that reduces the first resonance frequency to a second resonance frequency substantially equal to the transmission frequency is provided as the IC tag. A reader having a large antenna is disposed near the tag and performs non-contact communication with the IC tag using a reader / writer having a small antenna, and the communication distance with the IC tag exceeds a predetermined distance. Non-contact communication with the IC tag is performed at the first resonance frequency using a writer.

  Here, a small antenna is one that is set to a level of radio wave intensity that can be handled with relative ease in each country's radio wave law (for example, a radio station or high-frequency equipment in the Japanese radio wave law). That fall under this category). On the other hand, a large antenna is one that has a transmission circuit that can output a stronger radio wave intensity than a small antenna so that the antenna size is increased so that the magnetic field strength reaches about 10 cm (for example, the Japanese Radio Law. In other words, it shall have a radio wave intensity at a level that requires type authentication and registration as a specific radio equipment).

  In addition, the reader / writer is a general term for all communication devices having an electric circuit such as a transmission / reception circuit and a control circuit and an antenna as schematically shown in FIG.

  According to such a non-contact communication method according to the present invention, by using an auxiliary antenna within a predetermined communication distance, the resonance frequency of the IC tag is reduced to a level equivalent to the transmission frequency of the reader / writer. For example, it is easy to apply a small antenna that is easy to obtain approval under the Radio Law, and when exceeding a predetermined communication distance, increase the strength of the return signal of the IC tag without using an auxiliary antenna. It is possible to easily establish optimal non-contact communication according to the communication distance by increasing the communication distance and compensating for the deterioration of the minimum operating magnetic field by using a large antenna.

  Furthermore, the auxiliary antenna may be disposed opposite to the IC tag on the side opposite to the reader / writer via the IC tag.

  In this case, since the auxiliary antenna is disposed opposite to the IC tag on the side opposite to the reader / writer via the IC tag, the IC is compared with the case where the auxiliary antenna is disposed between the IC tag and the reader / writer. It is possible to substantially increase the communication distance of non-contact communication while increasing the layout flexibility of the tag and the reader / writer.

  According to the present invention, it is possible to easily realize a non-contact communication system, a non-contact communication method, and an image forming apparatus using the same that enable stable communication according to the communication distance between the IC tag and the reader / writer. .

  Embodiments according to the present invention will be described below with reference to the drawings.

  First, a schematic configuration of a non-contact communication apparatus according to an embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1 (a), a non-contact communication system 1 according to the present invention sandwiches an IC tag 10, a reader / writer 20 disposed opposite to the IC tag 10, and a predetermined case. The auxiliary antenna 30 is disposed on the opposite side of the reader / writer 20 from the IC tag 10.

  A conventionally known IC tag can be used as the IC tag 10. An antenna coil, a transmission / reception circuit, a modulation / demodulation circuit, a power supply circuit, a non-volatile memory, and the like are mounted on the substrate, and the reader / writer 20 received by the antenna coil. Based on the transmitted wave from the power source, the power supply circuit secures the operating power supply, and the demodulation circuit demodulates the received signal to extract the control signal. Based on the control signal, for example, the content stored in the memory is read out. / Write is performed, and the result is modulated by the modulation circuit and returned to the reader / writer 20.

  Similarly, the reader / writer 20 can also adopt a conventionally known configuration. A loop antenna, a transmission / reception circuit, a modulation / demodulation circuit, and the like are mounted on the substrate, and a control signal to the IC tag 10 is, for example, ASK modulated ( (Amplitude Shift keying) is transmitted, and a reply signal from the IC tag 10 is demodulated to extract predetermined information.

  Further, in the present embodiment, the auxiliary antenna 30 constituting the resonance frequency reducing means has an equivalent circuit as shown in FIG. 1B, for example, in which a coil pattern is formed on a substrate and a capacitor is mounted. A set of coil patterns and a capacitor are connected in series to perform series resonance.

  By the way, generally, when performing non-contact communication using such an IC tag 10 and a reader / writer 20, the IC tag 10 transmits a communication (transmission) carrier wave (hereinafter referred to as a carrier wave) transmitted from an antenna of the reader / writer 20. 2) is used as electric power, and as shown in FIG. 2A, the closer the resonance frequency of the IC tag 10 is to the frequency of the carrier wave, the better the reception sensitivity and the operation is possible even with a small magnetic field strength. Here, FIG. 2A is a diagram schematically showing the relationship between the minimum operating magnetic field of the IC tag 10 and the resonance frequency. From FIG. 2A, in the vicinity of the frequency of the carrier wave (13.56 MHz in this example). It is understood that the minimum operating magnetic field (A / m) is minimized and the IC tag 10 operates most efficiently.

  On the other hand, the strength of the reply signal of the IC tag 10 is returned in a form in which the frequency of the reply signal (hereinafter also referred to as subcarrier wave) is added to the carrier wave, as shown in FIG. When the resonance frequency of the IC tag 10 is higher than the frequency of the carrier wave by approximately the frequency of the subcarrier wave, the strength (mV) of the return signal increases. Here, FIG. 2 (b) is a diagram schematically showing the relationship between the strength (mV) of the return signal of the IC tag 10 and the resonance frequency of the IC tag 10. From FIG. In this example, it is understood that the reply strength of the IC tag becomes maximum in the vicinity of 14.40 MHz obtained by adding the frequency of the subcarrier wave (in this example, 0.84 MHz) to 13.56 MHz.

  From the above relationship, the cause of communication errors is mainly due to insufficient magnetic field strength (antenna power) of the reader / writer 20 in non-contact communication at a distance of about 1 cm, whereas in non-contact communication at a distance of about 10 cm. Insufficient response signal is the main factor.

  That is, for example, when the IC tag 10 and the reader / writer 20 perform non-contact communication with each other in a state in which the IC tag 10 and the reader / writer 20 are arranged close to each other (for example, a distance of about 1 cm), the IC tag 10 and the reader / writer 20 are close to each other. Therefore, the reply signal has a sufficient strength, but a communication error often occurs due to insufficient antenna power (magnetic field) on the reader / writer 20 side. Therefore, making the resonance frequency of the IC tag 10 equal to the transmission frequency of the reader / writer 20 and improving (decreasing) the minimum operating magnetic field of the IC tag 10 contributes to stable non-contact communication.

  On the other hand, when performing non-contact communication in a state separated from the IC tag 10 (for example, a distance of about 10 cm), the reader / writer 20 cannot receive a reply signal even if the IC tag 10 obtains the minimum operating magnetic field. Since communication errors often occur, shifting the resonance frequency of the IC tag 10 to the high frequency side to increase the strength of the return signal contributes to stable non-contact communication.

  Therefore, in the non-contact communication method according to the present invention, appropriate non-contact communication according to the separation distance between the IC tag 10 and the reader / writer 20 is enabled as follows. The non-contact communication method according to the present invention will be described below.

First, the resonance frequency of the IC tag 10 is set to a _first resonance frequency R ₁ that is higher than the transmission frequency of the reader / writer 20. Specifically, the resonance frequency of the IC tag 10 and R _1, the transmission frequency f ₀ of the reader writer 20 (e.g., 13.56 MHz), the return signal frequency of IC tag 10 f ₁ (e.g., 0.84MHz) and Then, the resonance frequency R ₁ is set so that R ₁ ≈f ₀ + f ₁ . In this way, by shifting the resonance frequency R ₁ of the IC tag 10 to a higher frequency region than the frequency f _{0 of the} carrier wave, the strength of the return signal from the IC tag 10 is increased.

When close proximity communication is performed with a communication distance between the IC tag 10 and the reader / writer 20 of about 1 cm, the auxiliary antenna 30 and the small antenna (for example, the weak radio of the Radio Law) as shown in FIG. Non-contact communication is performed using a reader / writer 20 having a station or a high-frequency equipment). Specifically, the auxiliary antenna 30 is disposed on the opposite side of the reader / writer 20 via the IC tag 10 so as to face the IC tag 10, and non-contact communication between the IC tag 10 and the reader / writer 20 is performed. Do. As a result, the resonance frequency of the IC tag 10 is reduced to a _second resonance frequency R ₂ that is substantially equal to the frequency of the carrier wave to improve the minimum operating magnetic field, thereby realizing stable non-contact communication in proximity communication. For example, when the IC tag 10 or the reader / writer 20 is attached to a device constituting the image forming apparatus or the like to perform non-contact communication, the auxiliary antenna 30 is arranged between the IC tag 10 and the reader / writer 20. In comparison, the degree of freedom in layout of the device can be increased.

On the other hand, when remote communication is performed with a communication distance of about 10 cm between the IC tag 10 and the reader / writer 20, communication is performed using the reader / writer 20A having a large antenna. That is, the minimum operating magnetic field of the IC tag 10 in which the resonance frequency R ₁ is set higher than the frequency f _{0 of the} carrier wave by performing communication using a large antenna considering non-contact communication at a distance of about 10 cm from the beginning. Even if the deterioration occurs, stable non-contact communication in remote communication can be realized by increasing the magnetic field intensity generated from the large antenna of the reader / writer 20A.

  As described above, according to the communication distance to the IC tag 10, the transmission / reception by the small antenna + auxiliary antenna 30 or the transmission / reception by the large antenna is properly used, so that the optimum between the IC tag 10 and the reader / writer 20 according to the communication conditions. Non-contact communication is possible.

  Next, the verification result of the maximum communication distance by the non-contact communication method described above will be further described with reference to FIGS. Here, FIG. 3 is a diagram showing the verification result of the maximum communication distance when only the small antenna is used without using the auxiliary antenna, and FIG. 4 is the maximum communication distance when the small antenna + auxiliary antenna is used. It is a figure which shows the verification result. FIG. 5 is a diagram showing a verification result of the maximum communication distance when a large antenna is used.

  As can be understood from FIG. 3, when non-contact communication is performed using the reader / writer 20 using a small antenna, the resonance frequency of the IC tag 10 is higher than the frequency of the carrier wave (for example, 13.56 MHz). It can be seen that the communicable distance is reduced if it is misaligned. This is considered to be because the magnitude of the minimum operating magnetic field has a greater influence on the stability of contactless communication than the strength of the return signal of the IC tag 10 when performing proximity communication. It can be seen that the communication distance tends to decrease as the resonance frequency of the tag 10 shifts to the high frequency side.

  On the other hand, when the auxiliary antenna 30 according to the present invention is used, the resonance frequency of the IC tag 10 is reduced. Therefore, even if the IC tag 10 has a high resonance frequency as shown in FIG. It can be seen that the communication distance is improved.

Specifically, for example, as shown in FIG. 3, the resonance frequency of the IC tag 10 is set substantially equal to the transmission frequency of the reader / writer 20 (carrier wave frequency f ₀ : 13.56 MHz), and the auxiliary antenna 30 is set. When non-contact communication is performed without using, the maximum communication distance is about 17 mm, whereas when the resonance frequency of the IC tag 10 is shifted to the high frequency side (for example, 14.6 MHz), The maximum communication distance is reduced to about 11 mm.

  On the other hand, as shown in FIG. 4, the resonance frequency of the IC tag 10 is shifted to the high frequency side (for example, 14.2 MHz), and the auxiliary antenna 30 whose resonance frequency is 15.07 MHz is connected to the IC tag 10. When the distance d is 10 to 15 mm, the maximum communication distance is 17 to 18 mm. That is, even when the resonance frequency of the IC tag 10 is shifted to the high frequency side, by using the auxiliary antenna 30, the maximum communication distance is equivalent to the maximum communication distance (about 17 mm) when the auxiliary antenna 30 is not used. It is understood that the above is improved ((4) 14.2 MHz tag +15.07 MHz in the figure). Similarly, when the resonance frequency of the IC tag 10 is set to 14.2 MHz, the resonance frequency of the auxiliary antenna 30 is set to 14.35 MHz, and the separation distance d from the IC tag 10 is 10 to 15 mm (in the drawing) (3) 14.2 MHz tag + 14.35 MHz), the maximum communication distance is 17 to 18 mm, which is improved to be equal to or greater than the maximum communication distance of about 17 mm when the auxiliary antenna 30 is not used.

  On the other hand, when the resonance frequency of the IC tag 10 is set to 14.2 MHz and the resonance frequency of the auxiliary antenna is set to 12.96 MHz ((1) 14.2 MHz tag + 12.96 MHz in the figure), and the resonance of the IC tag 10 When the frequency is set to 14.2 MHz and the resonance frequency of the auxiliary antenna is set to 13.72 MHz ((2) 14.2 MHz tag + 13.72 MHz in the figure), the maximum communication distance is set to the auxiliary antenna. It can be seen that it cannot be improved to the same extent as the maximum communication distance (about 17 mm) when 30 is not used.

  That is, the improvement effect of the maximum communication distance varies depending on the resonance frequency of the auxiliary antenna 30 and the separation distance d (see FIG. 1) between the auxiliary antenna 30 and the IC tag 10, but the resonance frequency is set to 14 to 15 MHz. It has been found that a good communication distance can be obtained when the auxiliary antenna 30 is arranged at a separation distance d of 10 to 15 mm.

Next, when only the large antenna is used without using the auxiliary antenna 30, as shown in FIG. 5, the resonance frequency of the IC tag 10 is higher than the carrier wave frequency f ₀ (13.56 MHz in this example). Stable communication performance can be obtained in the higher frequency region, and the maximum communication is achieved especially when the frequency shifts to the higher frequency region by approximately the frequency f ₁ of the subcarrier wave (14.40 MHz in this example). It is understood that distance can be obtained.

This is because when non-contact communication is performed using a large antenna, it is more stable for non-contact communication to increase the return signal from the IC tag 10 than to increase the operating magnetic field of the IC tag 10. In particular, when the resonance frequency of the IC tag 10 is shifted to a frequency region higher than the carrier wave frequency f ₀ by approximately the frequency f ₁ of the subcarrier wave, the response signal of the IC tag 10 It is considered that the strength is optimally increased and the effect of improving the communication distance is high.

  As described above, when the non-contact communication method according to the present invention is used, the IC tag 10 whose resonance frequency is set to be shifted to a higher frequency side than the transmission frequency of the reader / writer 20, and the reader / writer 20 having a small antenna, When performing close proximity communication (for example, a distance of about 1 cm), the auxiliary antenna 30 is arranged in the vicinity of the IC tag 10 to 10 to 15 mm to improve the minimum operating magnetic field and transmit the reader / writer 20. The maximum communication distance equivalent to that of the IC tag 10 having the resonance frequency equivalent to the frequency can be obtained, and in the case of remote communication farther than this, the use of a large antenna can increase the strength of the return signal. It is possible to perform stable non-contact communication by compensating for the deterioration of the minimum operating magnetic field while maintaining. That is, optimal non-contact communication according to the separation distance can be realized for the same IC tag 10.

  In general, large antennas are assumed to be used for production and inventory management in limited places such as factories and warehouses. Since it suffices to deal with only in the area, the setting of the magnetic field strength (antenna power) has a high degree of freedom and enables flexible setting.

  On the other hand, in the case of small antennas, it is assumed that they are mass-produced, incorporated into products such as copiers, and shipped to various countries and regions. It is necessary to comply with different laws and certification procedures in each country and region, and it is necessary to narrow down the magnetic field strength (antenna power) to the minimum necessary in response to a request to respond to various regulations as easily as possible. Therefore, the magnetic field strength (antenna power) cannot be easily increased.

  From the standpoint of responding to the approval under the Radio Law, according to the non-contact communication system and non-contact communication method of the present invention, it is possible to properly use large antennas and small antennas according to the use, Stable contactless communication in each case is possible.

  Next, an image forming apparatus to which the non-contact communication system according to the present invention is applied will be described with reference to FIGS. Here, FIG. 6 is a schematic diagram showing a schematic configuration of an image forming apparatus to which the non-contact communication system according to the present invention is applicable, and FIG. 7 shows an example of attaching an auxiliary antenna to a toner cartridge as a replacement part. It is a schematic diagram.

  In FIG. 6, an image forming apparatus 50 according to the present embodiment employs an electrophotographic system. For example, color image information of a color original read by an image reading apparatus (not shown), a personal computer or image data (not shown). Color image information sent from an input device or the like is input, and based on the input image information, a recording medium is recorded by a conventionally known image forming means including a photosensitive drum, an exposure unit, a developing unit, a fixing unit, and the like. Image formation is performed on the top.

  For example, the image forming apparatus main body 50 includes a plurality of toner cartridges 60 (represented by one toner cartridge for the sake of simplicity) for each color, which are detachably provided from the toner cartridge 60. A desired image is formed on a recording medium by an image forming unit (not shown) using the supplied toner. Here, the IC tag 10 is attached to the toner cartridge 60, and the auxiliary antenna 30 is also detachably attached to the toner cartridge 60. The reader / writer 20 has a small antenna portion (for example, 23 mm × 17 mm) in a substantially rectangular substrate (for example, 23 mm × 45 mm), is fixedly installed on the main body side of the image forming apparatus 50, and It is connected to the device controller 70, and performs non-contact communication with the IC tag 10 based on a control command from the device controller 70. Further, in the present embodiment, the IC tag 10 and the reader / writer 20 are arranged to face each other with an interval of about 1 cm with the toner cartridge 60 attached to the image forming apparatus main body 50. Yes.

  Next, a configuration example of the toner cartridge 60 in which the auxiliary antenna 30 according to the present invention is detachably incorporated will be further described with reference to FIG. In this example, for convenience, a cylindrical toner cartridge 60 is used, the IC tag 10 is attached to the peripheral surface of the cylindrical toner cartridge 60, and the reader / writer 20 is close to the IC tag 10. It shall be attached to the position which opposes.

  As shown in FIG. 7A, a recess 60b having a slit-like opening and extending in the longitudinal direction of the toner cartridge is formed on one side surface 60a of the cylindrical toner cartridge 60. Then, as shown in FIG. 7B, the auxiliary antenna 30 can be attached to and detached from the toner cartridge 60 by inserting or pulling out the auxiliary antenna 30 into the recess 60b. The concave portion 60b is formed so that the auxiliary antenna 30 and the IC tag 10 face each other substantially in parallel with the auxiliary antenna 30 attached (inserted), and the toner cartridge 60 is connected to the image forming apparatus 50. For example, in the shipping stage where the toner cartridge 60 that is a replacement part is packed as a unit, the auxiliary antenna 30 is in a removed state, and the toner cartridge 60 is removed from the packing box to form an image. When the apparatus 50 is mounted, the auxiliary antenna 30 is mounted on the toner cartridge 60.

  Note that the above-described configuration example of the toner cartridge 60 is merely an example, and the auxiliary antenna 30 does not function when the toner cartridge 60 is removed, and the toner cartridge 60 is attached to the image forming apparatus 50. What is necessary is just to be comprised so that the antenna 30 may function. For example, as shown in FIG. 8C, the auxiliary antenna 30 is embedded in the toner cartridge 60 in advance, and the shield metal foil is peelable so as to cover the auxiliary antenna 30 in the vicinity of the auxiliary antenna 30. (For example, an aluminum foil) 31 may be arranged and the shield metal foil 31 may be peeled off when attached to the image forming apparatus 50.

  Further, the target to which the IC tag 10 is attached is not limited to the toner cartridge 60 described above. For example, replacement parts such as a photosensitive drum, a developing unit, and a fixing unit, or these are integrated into a unit. Of course, it can also be applied to an exchange unit.

  In the image forming apparatus 50 to which such a non-contact communication system is applied, for example, at the product shipment stage, the auxiliary antenna 30 is not attached in a factory or a warehouse, and the toner is in a packaging box. By performing non-contact communication with a replacement unit such as a cartridge 60 or other replacement parts (for example, a photosensitive drum cartridge) using a large antenna, data that differs depending on the delivery destination from the outside of the packing box immediately before shipment ( For example, the company code of the delivery destination can be written.

  On the other hand, since the resonance frequency of the IC tag was adjusted in consideration of the communication performance when using a small antenna, the communication distance does not increase even if a large antenna is used, and data is written from the outside of the packing box. I couldn't. That is, for example, for the toner cartridge 60 and the like, since it is necessary to write necessary data before storing it in the packing box, even if the toner cartridge itself is the same, data must be created and managed for each delivery destination. Inventory for each supplier was required.

  On the other hand, according to the present invention, since the communication distance when a large antenna is used can be extended, even if the data to be written differs for each delivery destination, the data from the outside of the packing box immediately before shipment. By writing, it becomes unnecessary to have a stock for each delivery destination, and it is possible to greatly reduce the amount of stock and contribute to the realization of proper stock management.

  On the other hand, in a use state where the toner cartridge 60 to which the auxiliary antenna 30 is attached or the exchange unit is attached to the image forming apparatus, non-contact communication is performed via the auxiliary antenna 30, whereby the small size mounted on the image forming apparatus 50. The reader / writer 20 having an antenna can stably read the tag ID stored and held in the IC tag 10 mounted on the toner cartridge 60, for example. In this way, by reading information necessary for ensuring image quality from the toner cartridge 60 and other consumables (replacement unit such as a photosensitive drum cartridge), the device can be made to function properly.

  That is, in the image forming apparatus to which the non-contact communication system according to the present invention is applied, a small antenna that is installed in an apparatus such as the image forming apparatus 50 and adjusted to minimize the antenna power is used in a factory, a warehouse, or the like. The large-sized antenna installed in the system enables appropriate and stable non-contact communication with one type of IC tag 10, such as transmission / reception of data necessary to ensure image quality in use and realization of an appropriate inventory amount at the shipping stage, Various functions can be realized according to the application. In particular, the small antenna provided in the image forming apparatus 50 has the magnetic field strength reduced to the minimum, and the antenna and the IC tag 10 are attached after a replacement part such as the toner cartridge 60 is mounted on the apparatus. Since the mutual positional relationship is fixed, various functions by non-contact communication can be stably realized in a wide range by applying the non-contact communication system and the non-contact communication method according to the present invention.

(A) is a schematic diagram which shows the structure of the non-contact communication apparatus which concerns on this invention, (b) is a figure which shows the equivalent circuit of the auxiliary antenna which concerns on this invention. (A) is a figure which shows the relationship between the resonant frequency of an IC tag, and the minimum operating magnetic field, (b) is a figure which shows the relationship between the resonant frequency of an IC tag, and a reply intensity | strength. It is a figure which shows the verification result of the maximum communication distance at the time of using only a small antenna without using an auxiliary antenna. It is a figure which shows the verification result of the maximum communication distance at the time of using a small antenna + auxiliary antenna. It is a figure which shows the verification result of the maximum communication distance at the time of using a large antenna. 1 is a schematic diagram illustrating an image forming apparatus to which a non-contact communication system according to the present invention is applicable. FIG. 4 is a schematic view illustrating the configuration of a toner cartridge in which an auxiliary antenna according to the present invention is incorporated. It is a typical conceptual diagram which shows the structure of the reader / writer based on this invention.

Explanation of symbols

1: contactless communication system, 10: IC tag, 20: reader / writer, 30: auxiliary antenna, 31: metal foil for shielding, 50: image forming apparatus, 60: toner cartridge, 60b: recess, 70: apparatus controller, d : Separation distance, f ₀ : carrier wave frequency, f ₁ : subcarrier wave frequency, R ₁ : first resonance frequency, R ₂ : second resonance frequency

Claims (6)

A reader / writer that performs non-contact communication using a predetermined communication carrier;
An IC tag whose resonance frequency is set to a first resonance frequency higher than the transmission frequency of the reader / writer;
Resonance frequency reduction means for reducing the resonance frequency of the IC tag from the first resonance frequency to a second resonance frequency substantially equal to the transmission frequency of the reader / writer in a predetermined case. Contact communication system.   The resonance frequency reducing means opposes an auxiliary antenna that reduces the resonance frequency of the IC tag substantially equal to the transmission frequency when the communication distance between the reader / writer and the IC tag is a predetermined distance or less. The contactless communication system according to claim 1, wherein the contactless communication system is configured by arranging.   3. The non-resonance according to claim 1, wherein the first resonance frequency is set to be higher than the transmission frequency of the reader / writer by approximately the frequency of the return signal from the IC tag to the reader / writer. Contact communication system. The non-contact communication system according to claim 2 or 3, and an image forming means for forming a predetermined image on a recording medium,
The reader / writer is fixedly installed in the apparatus housing,
The IC tag is provided in a replacement part that can be attached to and detached from the apparatus housing, and the IC tag is disposed so as to face the reader / writer when the replacement part is mounted.
The auxiliary antenna is provided so as to be detachable from the replacement part, and is disposed so as to face the reader / writer with the IC tag interposed therebetween in the mounted state.
In a state where the replacement part is removed from the apparatus housing, non-contact communication with the IC tag is performed without using the auxiliary antenna,
An image forming apparatus comprising: a contactless communication between the IC tag and the reader / writer via the auxiliary antenna when the replacement part is attached to the apparatus housing. Using a reader / writer that performs non-contact communication with a predetermined communication carrier wave, and an IC tag whose resonance frequency is set to a first resonance frequency higher than the transmission frequency of the reader / writer,
When the communication distance with the IC tag is within a predetermined distance, an auxiliary antenna that reduces the first resonance frequency to a second resonance frequency substantially equal to the transmission frequency is disposed in the vicinity of the IC tag. In addition, non-contact communication with the IC tag is performed using a reader / writer having a small antenna,
When a communication distance with the IC tag exceeds a predetermined distance, contactless communication with the IC tag is performed at the first resonance frequency using a reader / writer having a large antenna. Contactless communication method.   6. The non-contact communication method according to claim 5, wherein the auxiliary antenna is disposed opposite to the IC tag on the side opposite to the reader / writer via the IC tag.

Images