JP2005025452A - Tag information reading method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tag information reading method and device that senses information on a tag formed with magnetostrictive elements attached to paper or a medium other than the paper, near and away from the tag, thereby not only sensing one-bit information on existence not of the magnetostrictive elements but also sensing multiple bit information. <P>SOLUTION: A varying alternating field of a specific frequency is intermittently applied to the tag formed of the plurality of magnetostrictive elements attached to a medium. Magnetostrictive residual vibration which occurs in the magnetostrictive elements after the stop of the alternating field is detected. Based on the detected pattern of the magnetostrictive residual vibration, information on the tag is read. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tag information reading method and apparatus, and more particularly, to a tag information reading method and apparatus for detecting and reading tag information formed by magnetostrictive elements applied to paper or a medium other than paper in the vicinity and remotely of the tag. About.
[0002]
[Prior art]
In recent years, in stores handling merchandise such as goods, a tag is affixed to the merchandise goods in order to prevent theft of the merchandise, and the merchandise with the tag attached is installed in a gate shape near the entrance of the store A system has been proposed in which the state of these tags is detected by ON / OFF of 1 bit when passing through the tag detection device, and whether or not it has been settled to prevent shoplifting theft.
[0003]
Here, RFID (= Radio Frequency IDentification) tags, tags using magnetic materials, and the like are used as types of tags attached to products, etc., and these tags can be accurately detected near or remotely from the tags. Various tag detection devices are also provided.
[0004]
For example, as disclosed in Patent Document 1, it is possible to reliably extract only a signal generated due to the magnetic characteristics of a predetermined magnetic member with respect to a tag formed of a magnetic member, thereby increasing the probability of erroneous identification of the tag. A low-reliability tag detection method and article monitoring apparatus having a high and accurate detection probability have been proposed.
[0005]
[Patent Document 1]
JP-A-11-025369
[Problems to be solved by the invention]
However, since the proposed tag detection method and article monitoring apparatus are configured to detect a tag having the magnetic characteristic by using the magnetic characteristic of a predetermined magnetic member used as a tag, unnecessary tags other than the tag are required. A metal piece or the like is also detected, and the detected metal piece or the like acts as a noise signal.
[0006]
Further, since the tag detection method and the article monitoring apparatus proposed above can only detect 1-bit information indicating whether or not a tag has been detected, it cannot be applied to other systems that require multiple bits of information. .
[0007]
Therefore, the present invention detects not only the information of a tag formed by a magnetostrictive element attached to paper or a medium other than paper, in the vicinity and remotely of the tag, but also detects 1-bit information indicating the presence or absence of the magnetostrictive element. An object of the present invention is to provide a tag information reading method and apparatus capable of reading a plurality of bits of information.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 is directed to a tag information reading method for reading information on a tag formed by a plurality of magnetostrictive elements applied to a medium, and an alternating magnetic field having a specific frequency that sequentially changes with respect to the tag. The magnetostrictive residual vibration generated in the magnetostrictive element after the alternating magnetic field is stopped is detected, and the tag information is read based on the detection pattern of the magnetostrictive residual vibration.
[0009]
The invention of claim 2 is characterized in that, in the invention of claim 1, the specific frequency of the alternating magnetic field is changed from a low frequency to a high frequency or from a high frequency to a low frequency at predetermined time intervals.
[0010]
According to a third aspect of the present invention, in the first or second aspect of the present invention, the specific frequency is a frequency that substantially matches at least a self-resonant frequency of a magnetostrictive element forming the tag.
[0011]
According to a fourth aspect of the present invention, in any one of the first to third aspects of the invention, the detection of the residual magnetostrictive vibration is performed based on whether or not the number of residual magnetostrictive vibrations is equal to or greater than a predetermined number. And
[0012]
According to a fifth aspect of the present invention, in the first to third aspects of the invention, the residual magnetostrictive vibration is detected based on whether the level of the residual magnetostrictive vibration is equal to or higher than a predetermined value. And
[0013]
According to a sixth aspect of the present invention, in a tag information reading device that reads information on a tag formed by a plurality of magnetostrictive elements applied to a medium, an alternating magnetic field having a specific frequency that changes sequentially with respect to the tag is intermittently applied. An alternating magnetic field generating means for applying, a magnetostrictive residual vibration detecting means for detecting a residual magnetostrictive vibration generated in the magnetostrictive element after stopping the alternating magnetic field generated by the alternating magnetic field generating means, and the magnetostrictive residual vibration detecting means Tag information reading means for reading information on the tag based on a detection pattern of presence or absence of residual magnetostrictive vibration is provided.
[0014]
The invention according to claim 7 is the invention according to claim 6, wherein the alternating magnetic field generating means generates an alternating magnetic field of a specific frequency that changes from a low frequency to a high frequency or from a high frequency to a low frequency at a predetermined time interval. Features.
[0015]
The invention of claim 8 is characterized in that, in the invention of claim 6 or 7, the specific frequency is a frequency that substantially matches at least a self-resonant frequency of a magnetostrictive element forming the tag.
[0016]
The invention according to claim 9 provides the magnetostrictive residual vibration detecting means according to any one of claims 6 to 8, wherein the magnetostrictive residual vibration detecting means detects the residual magnetostrictive vibration based on whether or not the number of residual magnetostrictive vibrations is equal to or greater than a predetermined number. The presence or absence is detected.
[0017]
The tenth aspect of the present invention provides the magnetostrictive residual vibration detecting means according to any of the sixth to eighth aspects, wherein the magnetostrictive residual vibration detecting means determines whether the magnetostrictive residual vibration level is equal to or higher than a predetermined value. The presence or absence is detected.
[0018]
According to an eleventh aspect of the present invention, in any one of the sixth to tenth aspects, the magnetostrictive residual vibration detecting means is the alternating magnetic field generating means based on an electric signal generated based on the magnetostrictive residual vibration generated in the magnetostrictive element. And a filter circuit that selectively detects a frequency component corresponding to the specific frequency generated in (1).
[0019]
According to a twelfth aspect of the invention, in any one of the sixth to eighth aspects, the magnetostrictive residual vibration detecting means logarithmically amplifies an electric signal generated based on the magnetostrictive residual vibration generated in the magnetostrictive element. It is characterized by having.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0021]
FIG. 1 is a block diagram showing a configuration of a main part of a printing apparatus 100 according to an embodiment in which the tag information reading method and apparatus according to the present invention are applied to a printing apparatus.
[0022]
In FIG. 1, a printing apparatus 100 to which a tag information reading method and apparatus according to the present invention is applied includes a magnetostrictive element formed according to identification information unique to a printing paper for the purpose of preventing information leakage, maintaining confidentiality, or managing documents. The identification information is read from the printing paper to which the tag is attached, and the correspondence between the content such as the document and the identification information is used to prevent inadvertent disclosure of the content such as the document. This is a printing apparatus capable of preventing leakage.
[0023]
That is, the content such as a document printed by the printing apparatus 100 can compensate that the content such as the document is a legitimate confidential document from the correspondence between the content such as the document and the identification information unique to the printing paper. If the content such as this document is copied to another printing paper, the correspondence between the content such as the document and the identification information of the printing paper cannot be maintained. It becomes possible to prevent leakage of confidential information.
[0024]
As shown in FIG. 1, the printing apparatus 100 feeds paper feed trays 50a and 50b in which printing papers having different paper sizes are accumulated and the printing paper accumulated in the paper feeding trays 50a and 50b. According to the present invention, the paper feed rollers 51a and 51b to be carried out, the carry-in rollers 60a and 60b for carrying the fed printing paper 10 into the printing unit 40, and the carry-in rollers 60a and 60b and the printing unit 40 are arranged. The tag information reading device 30, a printing unit 40 that prints content on the printing paper 10, carry-out rollers 61 a and 61 b that discharge printed output paper on which content is printed by the printing unit 40, and the entire printing device 100 are controlled. A control unit 20 is provided.
[0025]
In this printing apparatus 100, when a user (not shown) designates a desired content, a print paper size, and the like from the print instruction terminal 80, a signal of information such as the content and the print paper size is printed via the network 90. The control unit 20 selects one of the paper feed trays 50a and 50b based on the input information input to the control unit 20 of the apparatus 100, and the paper feed roller 51a of one of the selected paper feed trays 50a and 50b. , 51b feeds the printing paper 10 to the carry-in rollers 60a, 60b.
[0026]
The identification information unique to the printing paper 10 given to the printing paper 10 is read by the tag information reading device 30 while the fed printing paper 10 is being conveyed to the printing unit 40 by the carry-in rollers 60a and 60b.
[0027]
The printing paper 10 conveyed to the printing unit 40 is printed with the desired content printed on the printing paper 10 by the printing unit 40 and discharged by the carry-out rollers 61 a and 61 b and read by the tag information reading device 30. 10 identification information and contents are associated with each other and stored and managed in a management table (not shown) of the server 70.
[0028]
With this configuration, it is possible to prevent inadvertent disclosure of the content such as the document from the correspondence between the content such as the document and the identification information unique to the printing paper 10, and leakage of confidential information due to inadvertent copying or the like. Can be prevented.
[0029]
By the way, the printing apparatus 100 according to this embodiment is configured to use a dedicated paper to which a tag representing identification information unique to the printing paper 10 has been assigned in advance, and for reading the identification information of the printing paper 10. A tag information reader 30 is provided.
[0030]
FIG. 2 is a diagram illustrating an example of a print sheet to which a tag representing identification information is attached.
[0031]
As shown in FIG. 2A, the printing paper 200 is made up of a plurality of magnetostrictive elements 1L201 and 2L202 formed in the shape of thin thin foils having different lengths that represent the identification information 210 that can identify the printing paper 200. It is included.
[0032]
The magnetostrictive elements 1L201 and 2L202 are formed of magnetostrictive elements such as ferrite and amorphous. The magnetostrictive elements such as amorphous have a so-called magnetostrictive characteristic that causes a dimensional change of the magnetostrictive element when a magnetic field is applied from the outside. is doing.
[0033]
When an alternating magnetic field having a predetermined frequency is transmitted to a magnetostrictive element having such magnetostrictive characteristics, the magnetostrictive element resonates with the frequency of the alternating magnetic field and vibrates magnetostrictively.
[0034]
Since the frequency at which the magnetostrictive element vibrates depends on the size and shape of the magnetostrictive element, the magnetostrictive element has a specific magnetostrictive vibration frequency (hereinafter referred to as “self-resonant frequency”) according to the size and shape of the magnetostrictive element. .)
[0035]
This magnetostrictive vibration is sustained while converging for a short time even if transmission of the alternating magnetic field transmitted to the magnetostrictive element is stopped.
[0036]
Here, for convenience of explanation, the magnetostrictive element receives an alternating magnetic field in the vicinity of the self-resonant frequency of the magnetostrictive element and vibrates magnetostrictively. After the magnetostrictive vibration, the alternating magnetic field transmitted to the magnetostrictive element is stopped for a short time. The vibration in which the magnetostrictive vibration of the magnetostrictive element is maintained is called “residual vibration”.
[0037]
Conversely, when a magnetostrictive element having magnetostrictive characteristics is subjected to a change in size by applying an external force, the magnetization state of the magnetostrictive element changes, so an alternating magnetic field having a frequency near the self-resonant frequency of the magnetostrictive element is changed. When the magnetostrictive vibration is transmitted to the magnetostrictive element, an electromagnetic wave corresponding to the magnetostrictive vibration frequency is emitted from the magnetostrictive element that is magnetostrictively vibrated.
[0038]
In the printing paper 200 shown in FIG. 2A, the magnetostrictive elements 1L201 and 2L202 are ferromagnetic materials having magnetostrictive characteristics such as amorphous as described above, and each has its own self-resonant frequency f1 (magnetostrictive element). 1L201) and f2 (magnetostrictive element 2L202).
[0039]
In the example of the printing paper 200, the self-resonant frequencies f1 and f2 are assumed to be f1 <f2.
[0040]
2B and 2C are diagrams showing magnetostrictive vibration and residual vibration of the magnetostrictive elements 1L201 and 2L202 applied to the printing paper 200. FIG.
[0041]
As shown in FIGS. 2B and 2C, the magnetostrictive elements 1L201 and 2L202 applied to the printing paper 200 have their own self-resonant frequencies f1 (magnetostrictive element 1L201) and f2 (magnetostrictive element 2L202), respectively. Therefore, when the alternating magnetic field having the frequency f1 is transmitted to the printing paper 200, the magnetostrictive element 1L201 performs the magnetostrictive vibration 220 having the frequency f1 as shown in FIG. 2B, and the alternating magnetic field having the frequency f2 is transmitted to the printing paper 200. Then, the magnetostrictive element 2L202 performs a magnetostrictive vibration 222 having a frequency f2 as shown in FIG.
[0042]
The magnetostrictive element 1L201 receives the alternating magnetic field having the frequency f1, undergoes magnetostrictive vibration 220, and after that, even if transmission of the alternating magnetic field having the frequency f1 is stopped, the residual vibration 221 as shown in FIG. Similarly, after the magnetostrictive element 2L202 receives the alternating magnetic field of frequency f2 and magnetostrictive vibration 222, the residual vibration 223 as shown in FIG.
[0043]
In this way, the electromagnetic waves generated by the respective magnetostrictive vibrations of the plurality of magnetostrictive elements 1L201 and 2L202 applied to the printing paper 200 by transmitting while changing the frequency of the alternating magnetic field to the printing paper 200 are received and magnetostrictive. The presence / absence of the elements 1L201 and 2L202 can be detected.
[0044]
Therefore, a plurality of magnetostrictive elements having different self-resonance frequencies according to the identification information are combined and applied to the printing paper, transmitted to the printing paper while changing the frequency of the alternating magnetic field, and the frequency of the transmitted alternating magnetic field is By detecting the presence or absence of the magnetostrictive element, identification information unique to the printing paper 200 can be read.
[0045]
Therefore, the tag information reader 30 according to the present invention generates an alternating magnetic field having a predetermined frequency that is linearly changed from a low frequency to a high frequency with respect to a plurality of magnetostrictive elements having different self-resonance frequencies representing identification information unique to printing paper. Identification information corresponding to the presence or absence of a plurality of magnetostrictive elements having different self-resonant frequencies applied to the printing paper by detecting electromagnetic waves generated by magnetostrictive vibration of each magnetostrictive element for each frequency of the transmitted alternating magnetic field. It is configured to read.
[0046]
FIG. 3 is a block diagram illustrating a configuration of a main part of the tag information reading device 30 of the printing apparatus 100 illustrated in FIG. 1.
[0047]
In FIG. 3, the tag information reading device 30 has a predetermined frequency that is linearly changed from a low frequency to a high frequency with respect to the printing paper 330 provided with a plurality of magnetostrictive elements 331 having different self-resonance frequencies corresponding to identification information. By transmitting an alternating magnetic field and detecting an electromagnetic wave generated by magnetostrictive vibration of the magnetostrictive element 331 with respect to each frequency of the transmitted alternating magnetic field, the identification information given to the printing paper 330 is read.
[0048]
In FIG. 3, the same parts as those of the printing apparatus 100 shown in FIG.
[0049]
As shown in FIG. 3, the tag information reader 30 generates a transmission unit 300 that generates and transmits an alternating magnetic field to a plurality of magnetostrictive elements 331 that form identification information given to the printing paper 330, and the printing paper 330. A plurality of applied magnetostrictive elements 331 receive an alternating magnetic field transmitted from the transmitting unit 300 and undergo magnetostrictive vibration, and a receiving unit 310 that detects electromagnetic waves emitted by the magnetostrictive vibration, and synchronization between the transmitting unit 300 and the receiving unit 310 A transmission / reception effective period controller 320 that performs control for controlling the tag information, and a tag information reading control unit 340 that performs overall control of the entire tag information reading device 30.
[0050]
As described above, the plurality of magnetostrictive elements 331 provided on the printing paper 330 are made of a ferromagnetic material having magnetostrictive characteristics such as amorphous and are formed in a thin foil shape or a shino shape. A plurality of magnetostrictive elements 331 having different resonance frequencies are applied to the printing paper 330.
[0051]
The transmission unit 300 transmits an alternating magnetic field having a predetermined frequency to the printing paper 330 for a predetermined time, and then stops transmitting the alternating magnetic field. During the next predetermined time, the receiving unit 310 causes the plurality of magnetostrictive elements 331 to be transmitted. The electromagnetic wave emitted by the residual vibration of any one of the magnetostrictive elements 331 is detected.
[0052]
The control of stopping the transmission of the alternating magnetic field after transmitting the alternating magnetic field of a predetermined frequency to the printing paper 330 for a predetermined time is affected by the alternating magnetic field transmitted from the transmitting unit 300 to the receiving unit 310. This is performed to facilitate reception of electromagnetic waves emitted from any one of the plurality of magnetostrictive elements 331 applied to the printing paper 330.
[0053]
Synchronous control that synchronizes transmission and reception such that an alternating magnetic field having a predetermined frequency is transmitted during the predetermined time and an electromagnetic wave generated from any one of the plurality of magnetostrictive elements 331 is received during the predetermined time is The transmission / reception effective period controller 320 controls the transmission / reception validity period.
[0054]
The transmitting unit 300 provides an operating voltage of a voltage controlled oscillator (VCO = Voltage Controlled Oscillator) 302 to generate an alternating magnetic field having a frequency near the self-resonant frequency of each of the plurality of magnetostrictive elements 331 applied to the printing paper 330. Transmission frequency controller 301, voltage-controlled oscillator 302 that generates a waveform signal having a frequency according to the voltage controlled by transmission frequency controller 301, waveform signal having a frequency generated by voltage-controlled oscillator 302, and transmission / reception effective A frequency converter 303 that combines a synchronization control signal for synchronizing transmission and reception by the period controller 320; a transmitter 304 that amplifies the waveform signal input from the frequency converter 303 and outputs the amplified signal to the transmission antenna 305; , Alternating magnetic field of waveform signal input from transmitter 304 And a transmission antenna 305 for transmitting to the printing paper 330.
The receiving unit 310 is generated by residual vibration of one of the plurality of magnetostrictive elements 331 applied to the printing paper 330 by an alternating magnetic field having a predetermined frequency transmitted from the transmitting antenna 305 of the transmitting unit 300. A receiving antenna 311 that receives electromagnetic waves, a limiter 312 that limits a frequency band of a signal input through the receiving antenna 311 (hereinafter referred to as a “detection signal”), and a detection signal that is limited by the limiter 312. A low-pass filter (LPF = Low Pass Filter) 313 that removes high-frequency noise components and a high-pass filter (HPF = High Pass Filter) 314 that removes low-frequency noise components, and a detection signal that has been filtered and narrowed Amplifier that amplifies the signal to a digitizable level 315, a detector 316 that detects the detection signal amplified by the amplifier 315 and extracts the frequency component of the electromagnetic wave emitted by the residual vibration, and counts the frequency of the frequency component of the residual vibration detected by the detector 316. A detection counter 317 and a display 318 for displaying a count value counted by the detection counter 317 are provided. The low-pass filter 313 and the high-pass filter 314 have a reception frequency band corresponding to a change in the transmission frequency of the transmission unit 300. Restrict.
[0055]
The detection signal limited by the limiter 312 is based on a voltage signal of a predetermined frequency input from the reception frequency controller 319 corresponding to the voltage signal generated by the transmission frequency controller 301 of the transmission unit 300, and the high-pass filter 313. The filter 314 limits the band near the transmission frequency.
[0056]
The processing for the detection signal performed by each of the low-pass filter 313, the high-pass filter 314, the amplifier 315, the detector 316, and the detection counter 317 is based on the transmission / reception synchronization control signal generated by the transmission / reception effective period controller 320. Done.
[0057]
The residual vibration count value counted by the detection counter 317 is displayed on the display 318 and input to the tag information reading control unit 340, and the magnetostrictive element 331 having the self-resonance frequency of the frequency is applied to the printing paper 330. It is determined whether or not it has been done.
[0058]
The tag information reading control unit 340 determines whether the magnetostrictive element 331 applied to the printing paper 330 is present or not. If the count value input from the detection counter 317 of the receiving unit 310 is equal to or greater than a predetermined value, the frequency of the alternating magnetic field transmitted. If the count value input from the detection counter 317 is not equal to or greater than a predetermined value, it is determined that there is no magnetostrictive element 331 corresponding to the frequency of the transmitted alternating magnetic field.
[0059]
Note that the tag information reading device 30 in this embodiment shown in FIG. 3 is an example in which the transmission antenna 305 of the transmission unit 300 and the reception antenna 311 of the reception unit 310 are arranged to face each other with the printing paper 330 interposed therebetween. As shown, when the transmitting antenna 305 and the receiving antenna 311 are used as a single antenna and an alternating magnetic field of a predetermined frequency generated by the transmitting unit 300 is transmitted, the antenna is switched to the transmitting unit 300 and connected to the magnetostrictive element. When receiving the electromagnetic wave emitted by the residual vibration 331, the antenna may be switched and connected to the receiving unit 310.
[0060]
Further, in the detection counter 317, a log (= Log) amplifier may be used in order to increase the number of times of residual vibration to be detected.
[0061]
FIG. 4 is a diagram for explaining the operation of the tag information reading device 30 when the tag information reading device 30 shown in FIG. 3 reads the identification information given to the printing paper.
[0062]
The operation when the tag information reading device 30 reads the identification information of the printing paper will be described with reference to FIGS.
[0063]
FIG. 4A is a diagram illustrating an example of a printing paper 400 in which a plurality of magnetostrictive elements having different self-resonant frequencies are combined to form 8-bit identification information and applied to the printing paper.
[0064]
As shown in FIG. 4A, the printing paper 400 includes a plurality of magnetostrictive elements 1M401, 2M402, 3M403, 4M404, 5M405, 6M406 formed in the shape of thin thin foils having different lengths representing the identification information 410, 7M407 and 8M408 are inserted, and each magnetostrictive element is in the order of magnetostrictive elements 1M401, 2M402, 3M403, 4M404, 5M405, 6M406, 7M407, 8M408, f1, f2, f3, f4, f5, f6, f7, f8, respectively. Has a self-resonant frequency.
[0065]
The tag information reading device 30 transmits, to the printing paper 400, eight predetermined alternating magnetic fields of f2, f3, f4, f5, f6, f7 and high frequency f8 in order from the low frequency f1 to the predetermined frequency. 8-bit information is detected by a combination of the presence or absence of a magnetostrictive element having a self-resonant frequency corresponding to each frequency of the alternating magnetic field.
[0066]
Therefore, it is possible to read the information as a desired number of bits by increasing or decreasing the number of steps of the alternating magnetic field transmitted to the printing paper 400 according to the number of bits forming information.
[0067]
The level of each self-resonant frequency is assumed to be f1 <f2 <f3 <f4 <f5 <f6 <f7 <f8.
[0068]
The tag information reading control unit 340 of the tag information reading device 30 transmits an alternating magnetic field having a predetermined frequency that is linearly changed from the low frequency f1 to the high frequency f8 to the printing paper 400 shown in FIG. The instruction signal is input to the transmission frequency controller 301 of the transmission unit 300.
[0069]
FIG. 4B is a diagram showing the frequency change of the waveform signal generated by the voltage controlled oscillator 302 by the voltage supplied from the transmission frequency controller 301 based on the instruction of the tag information reading control unit 340.
[0070]
As shown in FIG. 4B, the tag information reading control unit 340 inputs an instruction signal for generating an alternating magnetic field having a low frequency f1 for Δt420 for a predetermined time to the transmission frequency controller 301 of the transmission unit 300 for transmission. The frequency controller 301 supplies an operating voltage to the voltage controlled oscillator 302 based on an instruction from the tag information reading control unit 340, and the voltage controlled oscillator 302 generates a waveform signal having a frequency f1 for Δt420 for a predetermined time.
[0071]
The waveform signal of the frequency f1 generated by the voltage controlled oscillator 302 is input to the frequency converter 303, and the frequency converter 303 receives the waveform signal input from the voltage controlled oscillator 302 from the transmission / reception effective period controller 320. Output to the transmitter 304 based on the synchronization control signal for synchronizing transmission and reception, and the transmitter 304 amplifies the waveform signal input from the frequency converter 303 and transmits the waveform signal having the frequency f1 via the transmission antenna 305. An alternating magnetic field is transmitted to the printing paper 400 for a predetermined time Δt.
[0072]
When an alternating magnetic field having a frequency f1 is transmitted to the printing paper 400, the magnetostrictive element having the self-resonant frequency f1 among the plurality of magnetostrictive elements 1M401, 2M402, 3M403, 4M404, 5M405, 6M406, 7M407, and 8M408 representing the identification information 410. 1M401 vibrates magnetostrictively, and the magnetostrictive vibration of the magnetostrictive element 1M401 remains vibrated for a short time even when transmission of the alternating magnetic field of frequency f1 is stopped.
[0073]
Since the electromagnetic wave is emitted from the magnetostrictive element 1M401 while the magnetostrictive element 1M401 is undergoing magnetostrictive vibration and residual vibration, the receiving unit 310 transmits the electromagnetic wave emitted by the residual vibration of the magnetostrictive element 1M401 via the receiving antenna 311 for a predetermined time. Detect during Δt.
[0074]
The synchronization control for synchronizing the transmission and reception is transmitted to Δt 420 during the time when the waveform signal of the frequency f1 is generated by the voltage controlled oscillator 302, for example, as shown in FIGS. 3 (c) and 3 (d). / The reception valid period controller 320 performs control such that Δts 430 is transmitted for a predetermined time as shown in the transmission interval of FIG. 3C, and during the predetermined time as shown in the reception interval of FIG. Control is performed so as to receive the electromagnetic wave emitted by the residual vibration of the frequency f1 of the magnetostrictive element 1M401 by Δtr440.
[0075]
An electromagnetic wave signal (hereinafter referred to as “detection signal”) emitted by the residual vibration of the magnetostrictive element 1M401 input via the receiving antenna 311 is input to the limiter 312 and band-limited, and transmitted from the transmission unit 300. The high-frequency noise component and the low-frequency noise component are removed by the low-pass filter 313 and the high-pass filter 314 corresponding to the change in the transmission frequency to be input to the amplifier 315.
[0076]
The amplifier 315 power-amplifies the detection signal filtered in the vicinity of the transmission frequency by the low-pass filter 313 and the high-pass filter 314 and inputs it to the detector 316, and the residual vibration frequency component of the magnetostrictive element 1M401 is extracted by the detector 316.
[0077]
The signal of the residual vibration frequency component of the magnetostrictive element 1M401 extracted by the detector 316 is counted by the detection counter 317, and the counted value is input to the display 318 and the tag information reading control unit 340.
[0078]
Based on the count value input from the detection counter 317, the tag information reading control unit 340 causes the magnetostrictive element 1M401 having the self-resonant frequency f1 to be applied to the sheet 400 when the count value indicates a residual vibration that is greater than or equal to a predetermined value. If it is determined that it is present and converted into information “1” and the count data does not indicate a residual vibration greater than or equal to a predetermined value, it is determined that the magnetostrictive element 1M401 having the self-resonant frequency f1 does not exist on the sheet 400. It is converted into information “0”.
[0079]
As shown in FIGS. 4B and 4C, when an alternating magnetic field having a frequency f1 is transmitted to the printing paper 400 for a predetermined time via the transmission antenna 305 of the transmission unit 300, Δts 430 is transmitted to the printing paper 400. Since the electromagnetic wave is emitted by the magnetostrictive vibration of the applied magnetostrictive element 1M401, the electromagnetic wave emitted by the residual vibration of the magnetostrictive element 1M401 is detected and detected at Δtr440 during a predetermined time in the receiving section of FIG. Based on the result, the tag information reading control unit 340 converts the detection information into “1” 450 as shown in FIG.
[0080]
Similar to the above-described operation, when an alternating magnetic field having the frequency f2 is transmitted to the printing paper 400 via the transmitting antenna 305 of the transmitting unit 300 for a predetermined time Δts431, when transmitted, the magnetostriction having a predetermined time Δtr441 and a self-resonant frequency f2 is obtained. The reception unit 310 detects the electromagnetic wave emitted from the element 2M402 via the reception antenna 311 and converts the detection information into information “1” 451.
[0081]
By repeating this operation in the same manner until the frequency of the alternating magnetic field reaches f8, it corresponds to the presence or absence of each magnetostrictive element 1M401, 2M402, 3M403, 4M404, 5M405, 6M406, 7M407, 8M408 applied to the printing paper 400. The detected detection information is converted into “1”, “1”, “1”, “1”, “1”, “1”, “1”, “1” as shown in FIG. The identification information 400 is output from the information reading control unit 340 to the control unit 20 as “11111111”.
[0082]
When the frequency of the alternating magnetic field reaches f8, a waveform signal of frequency f1 is generated again and the same operation is repeated.
[0083]
In the printing paper 400 shown in FIG. 4A, an example is shown in which each magnetic body 1M401, 2M402, 3M403, 4M404, 5M405, 6M406, 7M407, and 8M408 are arranged in a line. Each magnetic body may be arranged at an arbitrary position in the printing paper 400.
[0084]
FIG. 5 is a flowchart showing how the tag information reading device 30 according to the present invention shown in FIG. 3 reads identification information made up of a plurality of magnetostrictive elements applied to a printing paper, and FIG. This identification information is a diagram showing an example of a printing paper to which other identification information is assigned.
[0085]
A method of reading the identification information 610 given to the printing paper 600 will be described with reference to FIGS.
In the printing paper 600 shown in FIG. 6A, for convenience of explanation, 1M401 of the plurality of magnetostrictive elements 1M401, 2M402, 3M403, 4M404, 5M405, 6M406, 7M407, and 8M408 shown in the printing paper 400 of FIG. An example in which identification information 610 formed by 2M402, 4M404, 5M405, 6M406, and 7M407 excluding 3M403 and 8M408 is given will be described.
[0086]
The magnetostrictive elements 2M402, 4M404, 5M405, 6M406, and 7M407 representing the identification information 610 of the printing paper 600 have self-resonant frequencies f2, f4, f5, f6, and f7, respectively, as described above with reference to FIG. .
[0087]
Therefore, in order to detect the presence / absence of a plurality of magnetostrictive elements having different self-resonance frequencies applied to the printing paper 600, the frequency of the alternating magnetic field transmitted to the printing paper 600 is linearly changed from low to high. Change and send.
[0088]
Note that, as described above, the tag information reading device 30 in this embodiment has eight stages of f2, f3, f4, f5, f6, f7 and high frequency f8 in order from the low frequency f1. An alternating magnetic field is transmitted to the printing paper 600, and 8-bit information is detected by a combination of the presence or absence of a magnetostrictive element having a self-resonant frequency corresponding to each frequency of the transmitted alternating magnetic field.
[0089]
First, the transmission unit 300 generates an alternating magnetic field having a low frequency f1 and transmits it to the printing paper 600 for a predetermined time (step 500).
If a magnetostrictive element having the self-resonant frequency of f1 exists in the magnetostrictive elements 2M402, 4M404, 5M405, 6M406, and 7M407 forming the identification information of the printing paper 600, the magnetostrictive element vibrates.
[0090]
Then, the magnetostrictive vibration causes residual vibration even after transmission of the alternating magnetic field having the frequency f1 is stopped, and electromagnetic waves are emitted by the residual vibration.
[0091]
Therefore, in order to detect this residual vibration, after the transmission of the alternating magnetic field having the frequency f1 is stopped, the receiving unit 310 receives electromagnetic waves emitted from the printing paper 600 for a predetermined time.
[0092]
In order to remove a noise signal or the like from the received electromagnetic wave signal (detection signal), the signal fr corresponding to the frequency f1 of the transmitted alternating magnetic field is set in the reception filter, and the noise component is removed from the detection signal (step 501). Then, the detection signal from which the noise component is removed is detected to extract a residual vibration component signal (step 502).
[0093]
If a predetermined number or more of residual vibrations can be detected based on the residual vibration component signal extracted from the detection signal (YES in step 503), a magnetostrictive element having a self-resonant frequency of f1 exists on the printing paper 600. Then, the information is converted into information “1” (step 504), and if a predetermined number of residual vibrations cannot be detected (NO in step 503), a magnetostrictive element having a self-resonant frequency of f1 exists on the printing paper 600. It is judged not to be converted into information “0” (step 505).
[0094]
In the example of the printing paper 600, since there are no magnetostrictive elements having the self-resonant frequency f1 among the plurality of magnetostrictive elements M402, 4M404, 5M405, 6M406, and 7M407 forming the identification information 610, the information “0” is displayed. Converted.
[0095]
FIGS. 6B, 6C, and 6D show detection of a predetermined number or more of residual vibrations corresponding to the frequencies f1 to f8 (FIG. 6B) transmitted to the printing paper 600. FIG. It is a figure which shows the presence or absence (FIG.6 (c)) and the detection information (FIG.6 (d)) corresponding to this detection result.
[0096]
When the detection of the received signal when the alternating magnetic field with the transmission frequency f1 is transmitted to the printing paper 600 is completed, the frequency of the alternating magnetic field to be transmitted next is changed to f2 = f1 + Δf, which is increased by Δf, and the above step 500 is started. The same processing is sequentially performed.
[0097]
If the frequency of the alternating magnetic field to be transmitted is changed to f2, the signal fr corresponding to this transmission frequency f2 is set in the reception filter (NO in step 506, step 507). When the frequency of the alternating magnetic field transmitted to the printing paper 600 is f2, the magnetostrictive element 2M402 applied to the printing paper 600 undergoes magnetostrictive vibration and residual vibration. Therefore, the electromagnetic wave emitted by the residual vibration of the magnetostrictive element 2M402 is reduced. It is detected that the magnetostrictive element 2M402 having the self-resonant frequency of f2 is present on the printing paper 600, and is converted into information “1”.
[0098]
Further, the frequency of the alternating magnetic field to be transmitted is changed from f2 to f3 increased by Δf, the same processing as described above is performed, and it is determined whether or not the printing paper 600 has a magnetostrictive element having the self-resonant frequency f3, The process is repeated until the frequency of the alternating magnetic field that is converted into either information “0” or “1” according to the determination result and transmitted to the printing paper 600 reaches f8 (step 507).
[0099]
As described above, the alternating magnetic field is transmitted while linearly changing from the low frequency f1 to the high frequency f8, and emitted by the residual vibrations of the magnetostrictive elements 2M402, 4M404, 5M405, 6M406, and 7M407 applied to the printing paper 600. By detecting the electromagnetic wave generated, detection information “0”, “1”, “0”, “1”, “1”, “1”, “1”, “0” as shown in FIG. ”Is detected, and identification information“ 0101110 ”of the printing paper 600 as shown in FIG.
[0100]
In this embodiment, the tag information reading method and apparatus according to the present invention can prevent inadvertent document disclosure of content such as documents and prevent leakage of confidential information due to inadvertent copying or the like. Although the example applied to a possible printing apparatus has been shown, the tag information reading method and apparatus according to the present invention may be applied to a copying machine, a warning device, etc. to prevent leakage of confidential information or prevent theft of goods, etc. Good.
[0101]
【The invention's effect】
As described above, according to the present invention, an alternating magnetic field having a specific frequency that sequentially changes is applied to the tag intermittently, and after detecting the magnetostrictive residual vibration generated in the magnetostrictive element after the alternating magnetic field is stopped, Since the information of the tag is read based on the detection pattern of the magnetostrictive residual vibration, a multi-bit signal is detected without detecting an unnecessary noise signal other than the signal generated by the magnetostrictive vibration of the magnetostrictive element or the like forming the tag. There is an effect that it is easy to read information.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a main part of a printing apparatus 100 according to an embodiment in which a tag information reading method and apparatus according to the present invention are applied to a printing apparatus.
FIG. 2 is a diagram illustrating an example of a print sheet to which a tag representing identification information is attached.
3 is a block diagram illustrating a configuration of a main part of a tag information reading device 30 of the printing apparatus 100 illustrated in FIG. 1. FIG.
4 is a diagram for explaining the operation of the tag information reading device 30 when the tag information reading device 30 shown in FIG. 3 reads the identification information given to the printing paper.
FIG. 5 is a flowchart showing a method of reading identification information composed of a plurality of magnetostrictive elements applied to a printing paper by the tag information reading device 30 according to the present invention shown in FIG. 3;
6 is a diagram illustrating an example of a printing paper to which identification information other than the identification information of the printing paper 400 illustrated in FIG. 4 is assigned. FIG.
[Explanation of symbols]
10, 330 Printing paper
20 Control unit
30 Tag information reader
40 Printing department
50a, 50b Paper feed tray
51a, 51b Paper feed roller
60a, 60b Loading roller
61a, 61b Unloading roller
70 servers
80 Printing instruction terminal
90 network
100 printing device
300 Transmitter
301 Transmission frequency controller
302 Voltage controlled oscillator
303 Frequency converter
304 transmitter
305 Transmitting antenna
310 Receiver
311 Receive antenna
312 Limiter
313 Low-pass filter
314 High-pass filter
315 amplifier
316 detector
317 Detection counter
318 indicator
320 Transmit / Receive Validity Controller
331 Identification information
340 Tag information reading control unit

Claims (12)

In a tag information reading method for reading information of a tag formed by a plurality of magnetostrictive elements applied to a medium,
Intermittently applying an alternating magnetic field of a specific frequency that sequentially changes to the tag,
Detecting the magnetostrictive residual vibration generated in the magnetostrictive element after stopping the alternating magnetic field;
A tag information reading method, wherein information of the tag is read based on a detection pattern of the magnetostrictive residual vibration. The tag information reading method according to claim 1, wherein the specific frequency of the alternating magnetic field is changed from a low frequency to a high frequency or from a high frequency to a low frequency at predetermined time intervals. The specific frequency is
3. The tag information reading method according to claim 1, wherein the tag information reading frequency is at least substantially equal to a self-resonant frequency of a magnetostrictive element forming the tag. The detection of the magnetostrictive residual vibration is
4. The tag information reading method according to claim 1, wherein the tag information reading method is performed based on whether or not the number of residual magnetostrictive vibrations is a predetermined number or more. The detection of the magnetostrictive residual vibration is
4. The tag information reading method according to claim 1, wherein the tag information reading method is performed based on whether the level of the magnetostrictive residual vibration is equal to or higher than a predetermined value. In a tag information reading device that reads information of a tag formed by a plurality of magnetostrictive elements applied to a medium,
Alternating magnetic field generating means for intermittently applying an alternating magnetic field of a specific frequency that sequentially changes to the tag;
Magnetostrictive residual vibration detecting means for detecting magnetostrictive residual vibration generated in the magnetostrictive element after stopping the alternating magnetic field generated by the alternating magnetic field generating means;
A tag information reading device comprising tag information reading means for reading information on the tag based on a detection pattern of presence or absence of magnetostrictive residual vibration detected by the magnetostrictive residual vibration detecting means. The alternating magnetic field generating means includes
7. The tag information reader according to claim 6, wherein an alternating magnetic field having a specific frequency that changes from a low frequency to a high frequency or from a high frequency to a low frequency is generated at predetermined time intervals. The specific frequency is
8. The tag information reading device according to claim 6, wherein the tag information reading device has a frequency substantially equal to at least a self-resonant frequency of a magnetostrictive element forming the tag. The magnetostrictive residual vibration detecting means is
9. The tag information reading device according to claim 6, wherein presence or absence of the magnetostrictive residual vibration is detected based on whether or not the number of the magnetostrictive residual vibrations is equal to or greater than a predetermined number. The magnetostrictive residual vibration detecting means is
9. The tag information reading method according to claim 6, wherein presence / absence of the magnetostrictive residual vibration is detected based on whether the level of the magnetostrictive residual vibration is equal to or higher than a predetermined value. The magnetostrictive residual vibration detecting means is
7. A filter circuit for selectively detecting a frequency component corresponding to a specific frequency generated by the alternating magnetic field generating means from an electric signal generated based on a magnetostrictive residual vibration generated in the magnetostrictive element. The tag information reading device according to any one of 1 to 10. The magnetostrictive residual vibration detecting means is
9. The tag information reading method according to claim 6, further comprising a log amplifier that logarithmically amplifies an electric signal generated based on a magnetostrictive residual vibration generated in the magnetostrictive element.

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