JP2005044298A - Tag information reading method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tag information reading method and device that can detect information about a tag nearby and at a distance with high accuracy and low power consumption. <P>SOLUTION: A filter selectively removes pulse signals from a detection signal including pulse signals generated when the application of a given alternating field to a tag formed from magnetic members causes pole inversions of the tag-forming magnetic members, and a differential amplifier amplifies the difference between the detection signal after pulse signal removal and the detection signal before pulse signal removal. Information about the tag is read according to the output of the differential amplifier. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a tag information reading method and apparatus, and more particularly, to information on a tag formed of a magnetic material applied to a medium for preventing information leakage, maintaining confidentiality, or managing a document due to magnetic characteristics of the magnetic material. The present invention relates to a tag information reading method and apparatus capable of being detected in the vicinity of and remotely from a tag with high accuracy with a simple analog-based configuration based on a signal generated, suppressing power consumption.

  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 that detects the status of these tags with a 1-bit ON / OFF when they pass the tag detection device, thereby judging whether the product has been settled and preventing shoplifting theft. Yes.

  In such a system, RFID (= Radio Frequiency IDentification) tags and tags using magnetic materials are used as the types of tags to be affixed to products and the like. Various tag detection devices that can be detected are also provided.

  As this type of detection device, a transmitting coil that transmits a predetermined alternating magnetic field and a receiving coil that detects the alternating magnetic field are provided facing each other, and a magnetic tag moves between the two coils. The change of the alternating magnetic field transmitted from the transmission coil by the tag is detected by the reception coil, and based on the detection result, it is determined that the tag is moved, that is, the product attached with the tag is moved. Products that are capable of preventing theft of goods etc. are well known and well known.

  By the way, in such an apparatus using magnetism, since the receiving coil also detects the movement of a magnetic body other than the predetermined tag attached to the product etc., the predetermined tag and the other magnetic body It is desired to provide a highly reliable apparatus that reliably identifies, has a low probability of misidentification, and has a high accurate detection probability.

  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.

JP-A-11-025369

  In the proposed tag detection method and article monitoring apparatus, in order to remove extraneous noise signals other than the predetermined tag generated in the receiving coil, the noise signal of the in-phase component is input to both ends of the receiving coil as a differential amplifier. Configured to remove.

  That is, the fundamental wave due to the alternating magnetic field frequency in which the in-phase component signal is reduced by the differential amplifier is further reduced by the notch filter, and digitized and then processed so as to improve the S / N ratio by a cyclic operation.

  Therefore, in the proposed tag detection method and article monitoring apparatus, in the cyclic operation after the received signal detected by the receiving coil is digitized, the effect of reducing noise below the LSB at the time of analog / digital conversion is reduced. Is small.

  Also, in a cyclic operation, when a non-periodic noise signal is input, the effect of reducing this noise signal is great, but when a periodic noise signal is input, the effect of reducing this noise signal is I can't expect much.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a tag information reading method and apparatus capable of detecting tag information in the vicinity and remotely with high accuracy and low power consumption.

  In order to achieve the above object, the invention according to claim 1 is a detection including a pulse signal generated at the time of magnetization reversal of the magnetic member forming the tag by applying a predetermined alternating magnetic field to the tag formed of the magnetic member. In the tag information reading method for reading the tag information based on the signal, the pulse signal is selectively removed from the detection signal by a filter, the detection signal from which the pulse signal is removed, and the detection signal before the pulse signal is removed Are differentially amplified by a differential amplifier, and the tag information is read based on the output of the differential amplifier.

  According to a second aspect of the present invention, in the first aspect of the present invention, the filter is a notch filter having a notch frequency set to a frequency approximately 3 to 9 times the frequency of the alternating magnetic field.

  According to a third aspect of the present invention, in the first aspect of the invention, the output of the differential amplifier is counted for a predetermined period, and the information on the tag is obtained from the relationship between the counted number of the pulse signals and the frequency of the alternating magnetic field. It is characterized by identifying.

  The invention of claim 4 is characterized in that, in the invention of claim 3, the alternating magnetic field is intermittently transmitted, and the transmission of the alternating magnetic field and the counting are performed in synchronization.

  According to a fifth aspect of the present invention, the tag is formed based on a detection signal including a pulse signal generated at the time of magnetization reversal of the magnetic member forming the tag by applying a predetermined alternating magnetic field to the tag formed of the magnetic member. In the tag information reading device that reads the information, a filter that selectively removes the pulse signal from the detection signal, a differential amplifier that differentially amplifies the detection signal and the output of the filter, and Tag information reading means for reading the tag information based on the output is provided.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the filter is a notch filter having a notch frequency set to a frequency approximately 3 to 9 times the frequency of the alternating magnetic field.

  According to a seventh aspect of the invention, in the fifth aspect of the invention, the tag information reading means includes a counting means for counting the output of the differential amplifier for a predetermined period, and the number of the pulse signals counted by the counting means. Tag information identifying means for identifying information on the tag from the relationship with the frequency of the alternating magnetic field.

  According to an eighth aspect of the present invention, in the fifth aspect of the present invention, the alternating magnetic field is intermittently transmitted to the tag formed of the magnetic member, and the counting by the counting means is synchronized with the transmission of the alternating magnetic field. It is characterized by performing.

  According to this invention, by applying a predetermined alternating magnetic field to a tag formed of a magnetic member, the pulse signal is filtered out from a detection signal including a pulse signal generated at the time of magnetization reversal of the magnetic member forming the tag. The detection signal selectively removed and the detection signal from which the pulse signal has been removed and the detection signal before the removal of the pulse signal are differentially amplified by a differential amplifier, and the tag information is read based on the output of the differential amplifier With this configuration, it is possible to detect tag information with high accuracy with little phase delay from the transmitted alternating magnetic field waveform.

  In addition, since the detection in practice is possible even if the detection cycle is repeatedly detected intermittently, the power consumption can be suppressed as compared with the method of always driving the detection circuit.

  Furthermore, no digital operation is required to detect the pulse signal generated when the magnetization of the magnetic member is reversed, so an analog / digital converter, memory, CPU, etc. are not required, and it can be realized with a simple analog-only configuration. There is an effect.

  The tag information reading method and apparatus according to the present invention provide identification information from a printing sheet to which a tag of magnetic material formed according to identification information unique to the printing sheet is provided for information leakage prevention, confidentiality protection, or document management. Tag information that can prevent unintentional document disclosure of content such as documents from the correspondence between content such as documents and identification information, and prevent leakage of confidential information due to inadvertent copying, etc. Method and apparatus.

  That is, content such as a document printed by a printing apparatus to which the tag information reading method and apparatus is applied is a confidential document in which the content such as the document is legitimate from the correspondence between the content of the document and identification information unique to the printing paper. If you try to copy the content of this document to other printing paper, the correspondence between the content of the document and the identification information of the printing paper cannot be maintained. It is possible to prevent leakage of confidential information due to inadvertent copying.

  FIG. 1 is a block diagram showing a configuration of a main part of an embodiment in which a tag information reading method and apparatus according to the present invention are applied to a printing apparatus.

  As shown in FIG. 1, the printing apparatus 100 feeds paper feed trays 50 a and 50 b in which printing papers having different paper sizes are accumulated and feeds the printing paper accumulated in the paper feed trays 50 a and 50 b. Tag information reading according to the present invention disposed between the rollers 51a and 51b, the carry-in rollers 60a and 60b for carrying the fed printing paper 10 into the printing unit 30, and the carry-in rollers 60a and 60b and the printing unit 30 An apparatus 40; a printing unit 30 that prints content on the printing paper 10; carry-out rollers 61a and 61b that discharge printed output paper on which the content is printed by the printing unit 30; and a control unit 20 that controls the entire printing apparatus 100. It has.

  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.

  The identification information unique to the printing paper 10 given to the printing paper 10 is read by the tag information reading device 40 while the fed printing paper 10 is being conveyed to the printing unit 30 by the carry-in rollers 60a and 60b.

  The printing paper 10 conveyed to the printing unit 30 is printed with desired content on the printing paper 10 in the printing unit 30 and discharged by the carry-out rollers 61a and 61b, and the control unit 20 uses the tag information reading device 40. The identification information of the read printing paper 10 and the content are associated with each other and stored and managed in a management table (not shown) of the server 70.

  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.

  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 is previously attached, and a tag for reading the identification information of the printing paper 10. An information reading device 40 is provided.

  FIG. 2 is a diagram illustrating an example of a print sheet to which tags formed of a plurality of magnetic members are attached according to identification information.

  As shown in FIG. 2, a plurality of magnetic materials 2L202 and 5L205 formed in thin lines having different lengths representing identification information 210 that can identify the printing paper 200 are attached to or printed on the printing paper 200. Yes.

  The magnetic members 2L202 and 5L205 are formed of a magnetic member such as ferrite or amorphous. When the magnetic member such as amorphous gives a predetermined alternating magnetic field from the outside, a steep pulse signal is generated at the time of magnetization reversal due to the large Barkhausen effect. It is a magnetic material having such characteristics as to emit.

  When an alternating magnetic field having a predetermined frequency is applied to a magnetic member having such characteristics, a steep magnetization reversal occurs due to the large Barkhausen effect when the magnetic member receives an alternating magnetic field greater than the coercive force of the magnetic member. A steep pulse signal is emitted.

  The magnetic field strength of the alternating magnetic field in which the magnetic member undergoes steep magnetization reversal due to the large Barkhausen effect varies depending on the coercive force of the magnetic member, and this coercive force varies depending on the length of the magnetic member.

  The magnetic members 2L202 and 5L205 formed on the printing paper 200 shown in FIG. 2 are magnetic members having a large Barkhausen effect such as amorphous as described above, and the magnetic member 2L202 has a length of 2L and the magnetic member 5L205. Has a length of 5L longer than the magnetic member 2L202.

  Therefore, the transmitting antenna and the receiving antenna are arranged to face each other, and the printing paper 200 to which the tags formed of the magnetic members 2L202 and 5L205 are attached is arranged between the antennas, and the alternating frequency of the predetermined frequency is transmitted from the transmitting antenna. When a magnetic field is transmitted and the transmitted alternating magnetic field is received by the receiving antenna, the magnetic members 2L202 and 5L205 forming the tag receive the alternating magnetic field and undergo magnetization reversal in addition to the transmitted alternating magnetic field waveform signal. This steep pulse signal is also detected.

  That is, when the magnetic field strength of the alternating magnetic field becomes equal to or greater than the respective coercive force of each of the magnetic members 2L202 and 5L205, the magnetic members 2L202 and 5L205 are each reversed in magnetization by the large Barkhausen effect, and each magnetic member emitted at that time 2L202 and 5L205 unique pulse signals are detected.

  FIG. 3 is a diagram showing a transmission signal waveform and a reception signal waveform of an alternating magnetic field transmitted to the printing paper 200 to which a tag formed by the magnetic members 2L202 and 5L205 is attached.

 FIG. 3A is a diagram illustrating a state in which the printing paper 200 is disposed between the transmitting antenna 301 and the receiving antenna 302 facing each other, and FIG. 3B is a transmission of an alternating magnetic field transmitted from the transmitting antenna 301. FIG. 3C is a diagram showing a signal waveform, and FIG. 3C is a diagram showing a received signal waveform received by the receiving antenna 302.

  As shown in FIG. 3 (a), when an alternating magnetic field of a transmission signal waveform 310 having a predetermined frequency as shown in FIG. 3 (b) is transmitted via a transmission antenna 301 using a detection device (not shown), a transmission signal is transmitted. Each of the magnetic members 2L202 and 5L205 forming the tag that receives the alternating magnetic field of the waveform 311 emits a steep pulse signal at the time of magnetization reversal according to the coercive force of each of the magnetic members 2L202 and 5L205 due to the large Barkhausen effect. A received signal waveform 311 as shown in FIG. 3C is detected.

  According to the received signal waveform 311 shown in FIG. 3 (c), the magnetic member 2L202 undergoes magnetization reversal when the time is “t1” and the magnetic field strength of the alternating magnetic field is “H2”, and the pulse signal “A” is generated at that time. When the time is “t3” and the magnetic field strength of the alternating magnetic field is “−H2”, the magnetization is reversed and a pulse signal “C” is generated.

  Further, the magnetic member 5L205 generates a pulse signal “B” by reversing the magnetization when the time is “t2” and the strength of the alternating magnetic field is “H5”, and the strength of the alternating magnetic field is “−H5” at the time “t4”. At this time, magnetization is reversed and a pulse signal “D” is generated.

  The unique pulse signals “A”, “B”, “C”, and “D” generated by the magnetic members 2L202 and 5L205 at the time of magnetization reversal can be continuously detected while the alternating magnetic field is transmitted. it can.

  Therefore, a tag combining a plurality of magnetic members having different coercive forces according to the identification information is applied to the printing paper, an alternating magnetic field having a predetermined frequency is transmitted to the printing paper, and each magnetic material forming the tag is switched to By detecting a unique pulse signal generated when the magnetization is reversed by the large Barghausen effect in response to a magnetic field, it is possible to identify the magnetic member that forms the tag applied to the printing paper.

  Further, by preparing a plurality of magnetic members having different coercive forces (lengths) in advance and setting identification information corresponding to the combination of each magnetic member, a magnetic member that forms a tag attached to the printing paper is provided. It is possible to identify and read identification information corresponding to the identified combination of magnetic members.

  However, when detecting a unique pulse signal generated at the time of magnetization reversal of the magnetic member due to such a large Barghausen effect, the transmission signal depends on various conditions such as the position, size, and noise signal of the magnetic members 2L202 and 5L205. There are problems such as the ratio of the received signal waveform 311 with respect to the waveform 310 being different and the noise signal being greatly affected.

  Therefore, in the tag information reading method and apparatus according to the present invention, even when various conditions such as the position, size, and noise signal of the magnetic member are different, the identification formed on the printing paper based on the received signal of the alternating magnetic field. For example, the following method is used so that a tag of a predetermined magnetic member corresponding to information can be reliably identified from other magnetic members and noise signals, and the tag of the predetermined magnetic member can be identified with high accuracy. It is configured to detect.

  FIG. 4 shows that the tag of the predetermined magnetic member corresponding to the identification information formed on the printing paper, the other magnetic material, the noise signal, etc. can be reliably identified, and the tag of the predetermined magnetic member can be identified with high accuracy. FIG. 5 is a diagram schematically illustrating a configuration circuit diagram of a main part configured as described above, and FIG. 5 is a diagram illustrating signal waveforms input or output in the circuit diagram illustrated in FIG. 4.

  A method for reliably identifying a tag of a predetermined magnetic member, a magnetic member other than that, a noise signal, etc., and identifying a tag of the predetermined magnetic member with high accuracy will be described with reference to FIGS.

  For convenience of explanation, the case where an alternating magnetic field having a transmission signal waveform 310 is transmitted to the printing paper 200 provided with the magnetic members 2L202 and 5L205 shown in FIG.

  As shown in the configuration circuit diagram 400 of FIG. 4, first, an alternating magnetic field of the transmission signal waveform 310 is applied to the magnetic members 2L202 and 5L205 forming the tag attached to the printing paper 200 and received via the reception antenna 302. The received signal (not shown) is amplified by the amplifier 401, and the in-phase noise component is removed through the filters of the low-pass filter 402 and the high-pass filter 403.

  If the setting frequency fL of the low-pass filter 402 is, for example, the transmission frequency of the alternating magnetic field is f0, fL = 30 × f0, which is approximately 30 times the transmission frequency f0, and the setting frequency fH of the high-pass filter 403 is, for example, the transmission frequency of the alternating magnetic field It is set as fH = 1/3 × f0, which is approximately one third of f0.

  When the low-pass filter 402 and the high-pass filter 403 remove noise components having the same phase as the alternating magnetic field from the received signal (not shown) based on the frequencies fL and fH set in this way and amplify them by the amplifier 404, the result shown in FIG. A received signal waveform 510 as shown is obtained.

In this received signal waveform 510, the magnetic member 2L202 forming the tag applied to the printing paper 200 receives an alternating magnetic field and receives the intrinsic pulse signals “A” and “C” when the magnetization is reversed by the large Barkhausen effect, The intrinsic pulse signals “B” and “D” at the time of magnetization reversal of the member 5L205 are included and detected.
When the received signal waveform 510 is input to the notch filter 405, the pulse signal “A”, “B”, “C”, and “D” components are removed from the received signal waveform 510, and a sine waveform as shown in FIG. 511 is output.

  In order to extract the sine waveform 511 by removing the pulse signal “A”, “B”, “C”, and “D” components from the received signal waveform 510, the set frequency of the notch filter 405 is set to, for example, the transmission frequency of the alternating magnetic field. The pulse signal “A”, “B”, “C”, and “D” components are removed from the received signal waveform 510 by setting within a range of about 3 to 9 times f0, that is, 3 × f0 to 9 × f0. As a result, a sine waveform 511 is output.

  When the received signal waveform 510 and the sine waveform 511 from which the pulse signals “A”, “B”, “C”, and “D” are removed by the notch filter 405 are input to the differential amplifier 406, the received signal waveform 510 is sine. The waveform 511 component is removed and a received pulse signal waveform 512 as shown in FIG. 5C is output.

  The pulse signals “A”, “B”, “C”, and “D” of the received pulse signal waveform 512 are pulse signals generated when the magnetic members 2L202 and 5L205 forming the tag attached to the printing paper are reversed in magnetization. It is a waveform signal.

  The detected pulse signal of the received pulse signal waveform 512 is counted for a predetermined time, and a magnetic member 2L202 that forms a tag attached to the printing paper 200 based on the correspondence between the counted number of pulses per predetermined time and the frequency of the alternating magnetic field. And 5L205 can be specified.

  Therefore, an alternating magnetic field having a predetermined frequency is applied to the tag applied to the printing paper, the pulse signal detected when the magnetic member forming the tag is reversed in magnetization, and the number of pulses per predetermined time of the detected pulse signal is counted, Based on the counted number of pulses and the frequency of the alternating magnetic field, the magnetic member forming the tag attached to the printing paper can be specified.

  In this way, the identification information and the combination of the types of magnetic members are managed in association with each other, and the identification corresponding to the combination of the types of magnetic members applied to the printing paper by detecting the magnetic member applied to the printing paper. Information can be read.

  FIG. 6 is a block diagram illustrating a configuration of a main part of the tag information reading device 40 of the printing apparatus 100 illustrated in FIG. 1.

  In FIG. 6, the same parts as those of the printing apparatus 100 shown in FIG. 1 are denoted by the same reference numerals as those used in FIG.

  As illustrated in FIG. 6, the tag information reading device 40 includes a transmission unit 600 that generates and transmits an alternating magnetic field, a reception unit 610 that receives the alternating magnetic field transmitted from the transmission unit 600, a transmission unit 600, and a reception unit 610. A transmission / reception effective period controller 620 that performs control to synchronize with the tag information, and a tag information reading control unit 640 that performs overall control of the entire tag information reading device 40.

  As described above, the plurality of magnetic members forming the tag attached to the printing paper 630 are formed in a thin line shape with a magnetic material that reverses magnetization by the large Barghausen effect such as amorphous, and the identification information includes Accordingly, a plurality of magnetic members 631 having different coercive forces are applied to the printing paper 630.

  The transmission unit 600 intermittently transmits an alternating magnetic field that is a sine wave having a predetermined frequency to the printing paper 630, and the reception unit 610 receives the transmitted alternating magnetic field in synchronization with the transmission unit 600.

  The predetermined frequency of the alternating magnetic field transmitted from the transmission unit 600 differs depending on the size and shape of the coil that is the transmission antenna 605 of the transmission unit 600 as described later, and the size and shape of the coil of the transmission antenna 605 are different. Depending on the frequency, a frequency in the range of approximately 500 Hz to 10 KHz is selected.

  When the magnetic member 631 applied to the printing paper 630 receives the alternating magnetic field transmitted from the transmission unit 600, the magnetization is reversed according to the coercive force of each magnetic member of the magnetic member 631, and a unique pulse signal at that time To emit.

  The receiving unit 610 receives each unique pulse signal emitted from each magnetic member of the magnetic member 631 and forms each tag attached to the printing paper 630 based on this received signal. Is detected.

  The transmission / reception effective period controller 620 controls the synchronization control for the reception unit 610 to detect the reception signal in synchronization with the transmission unit 600 that intermittently transmits an alternating magnetic field having a predetermined frequency.

  The transmission unit 600 includes a transmission frequency controller 601 that supplies an operating voltage of a voltage controlled oscillator (VCO = Voltage Controlled Oscillator) 602, and a voltage controlled oscillator that generates a waveform signal corresponding to the voltage controlled by the transmission frequency controller 601. 602, a frequency conversion for synthesizing a sine waveform signal of a predetermined frequency generated by the voltage controlled oscillator 602 and a synchronization control signal for synchronizing the transmission unit 600 and the reception unit 610 by the transmission / reception effective period controller 620 603, a transmitter 604 that amplifies the power of the sine waveform signal synchronously controlled from the frequency converter 603 and outputs the amplified signal to the transmission antenna 605, and a transmission that transmits an alternating magnetic field of the sine waveform signal input from the transmitter 604 An antenna 605 is provided.

  The receiving unit 610 receives the alternating magnetic field transmitted from the transmitting antenna 605, and a limiter 612 that limits the frequency band of a signal (hereinafter referred to as “received signal”) input via the receiving antenna 611. And a low-pass filter (LPF = Low Pass Filter) 613 that removes high-frequency noise components in the received signal limited by the limiter 612 and a high-pass filter (HPF = High Pass Filter) 614 that removes low-frequency noise components. A filter, a notch filter 615 that removes a unique pulse signal component emitted from each magnetic member of the magnetic member 631 from the received signal that has been narrowed by filtering, and a magnetic signal generated by the notch filter 615. A sinusoidal signal from which each unique pulse signal component is Differential amplifier 616 that differentially amplifies the received signal that has been filtered and narrowed by the high-pass filter 613 and the high-pass filter 614, and the differential amplifier 616 extracts each unique pulse signal emitted from each magnetic member. A detector 617 for detecting the amplified pulse signal, and a detection counter 618 for counting the pulse signal detected by the detector 617 for a predetermined time and counting the number of pulses per predetermined period are provided.

  Note that the transmission antenna 605 and the reception antenna 611 are formed in a coil shape, and the frequency of the alternating magnetic field transmitted through the transmission antenna 605 differs depending on the size and shape of the coil of the transmission antenna 605. A frequency in the range of approximately 500 Hz to 10 KHz is selected according to the size and shape of the.

The low-pass filter 613 and the high-pass filter 614 are configured to band-limit the reception frequency corresponding to the transmission frequency of the transmission unit 600. For example, the frequency fL of the low-pass filter 613 is approximately 30 times the transmission frequency f0. FL = 30 × f0, and the frequency fH of the high-pass filter 614 is set to fH = 1/3 × f0, which is approximately one third of the transmission frequency f0, and the band is limited. Remove noise components.
An operation in which the tag information reading device 40 reads the identification information 631 given to the printing paper 630 will be described.

  7 and 8 are diagrams for explaining the operation of the tag information reading device 40 when the tag information reading device 40 shown in FIG. 6 reads the identification information 631 given to the printing paper 630.

  The operation when the tag information reading device 40 reads the identification information of the printing paper will be described with reference to FIGS.

  FIG. 7 is a diagram illustrating an example of the printing paper 630 to which a tag 631 formed by combining a plurality of magnetic members having different coercive forces according to the identification information of the printing paper 630 is provided.

  As shown in FIG. 7, a plurality of magnetic members 2M702, 5M705, and 7M707 formed in thin lines having different lengths for forming tags representing identification information are encased in the printing paper 630. The members have coercivity of magnitudes H2, H5, and H7 (H2 <H5 <H7) in the order of magnetic members 2M702, 5M705, and 7M707.

  First, the tag information reading device 40 uses the transmission antenna 605 and the reception antenna 605 as a printing paper 630 provided with a tag 631 formed of a plurality of magnetic members 2M702, 5M705, and 7M707 between the transmission antenna 605 and the reception antenna 611. The transmission unit 600 transmits an alternating magnetic field having a predetermined frequency via the transmission antenna 605, and the transmitted alternating magnetic field is received by the reception antenna 611 of the reception unit 610.

  The alternating magnetic field transmitted via the transmission antenna 605 provides the voltage controlled oscillator 602 with an operating voltage that allows the transmission frequency controller 601 to generate a sine wave having a predetermined frequency based on an instruction from the tag information reading control unit 640, for example. Then, the voltage controlled oscillator 602 generates a transmission signal waveform 810 having a predetermined frequency as shown in FIG. 8A, and the generated sine wave alternating magnetic field is intermittently transmitted by the transmission / reception effective period controller 620 and the frequency converter 603. The transmission is controlled through the transmitter 604 and the transmission antenna 605.

  The alternating magnetic field transmitted from the transmission unit 600 is received by the reception antenna 611, and the received reception signal is filtered and amplified by the limiter 612, the low-pass filter 613, and the high-pass filter 614, as shown in FIG. 8B. A received signal waveform 811 is extracted.

  The low-pass filter 612 and the high-pass filter 613 remove high frequency noise component and low frequency noise component signals in the vicinity of the transmission frequency corresponding to the transmission frequency of the alternating magnetic field transmitted from the transmission unit 600.

  The extracted reception signal waveform 811 is transmitted by the magnetic members 2M702, 5M705, and 7M707 constituting the tag 631 attached to the printing paper 630 in addition to the signal of the transmission signal waveform 810 transmitted through the transmission antenna 605. By receiving the alternating magnetic field of the signal waveform 810, pulse signals “E”, “F”, “G”, “H”, “I” at the time of magnetization reversal according to the coercive force of each magnetic member 2M702, 5M705, 7M707. , “J” signal waveforms are included.

  The extracted reception signal waveform 811 is input to the notch filter 615, and the pulse signals “E”, “F”, “G”, “" generated from the reception signal waveform 811 when the magnetic members 2M702, 5M705, and 7M707 are magnetized. The signal components “H”, “I”, and “J” are removed to extract a sine waveform 812 as shown in FIG.

  The extracted sine waveform 812 (see FIG. 8C) and the received signal waveform 811 (FIG. 8B) are input to the differential amplifier 616, and the magnetic members 2M702, 5M705 as shown in FIG. , 7M707 extracts signal waveforms 813 of pulse signals “E”, “F”, “G”, “H”, “I”, and “J” generated when the magnetization is reversed.

  The pulse signal waveform 813 extracted by the differential amplifier 616 is detected by the detector 617, the number of pulse signals detected by the detector 617 per predetermined time is counted by the detection counter 618, and the count per predetermined time is counted. Are input to the tag information reading control unit 640.

  The tag information reading control unit 640 identifies the magnetic members 2M702, 5M705, and 7M707 that form the tag applied to the printing paper 630 based on the input number of pulses per predetermined time and the frequency of the alternating magnetic field. Identification information corresponding to the identified combination of the magnetic members 2M702, 5M705, and 7M707 is recognized as identification information of the printing paper 630 and output to the control unit 20.

  For example, a storage table (not shown) stores and manages a reference table in which the number of pulses per predetermined time corresponding to the combination of magnetic members forming the tag, the frequency of the alternating magnetic field, and identification information are associated with each other. The tag information reading control unit 640 refers to the reference table and recognizes the identification information based on the number of pulses per predetermined time input from the detection counter 618 and the transmitted frequency of the alternating magnetic field and outputs the identification information to the printing unit 20. To do.

  FIG. 9 is a flowchart showing a tag information reading method according to the present invention.

The tag information reading method will be described with reference to FIG.
First, a printing paper to which a tag formed of a plurality of magnetic members is attached is disposed between the transmitting antenna and the receiving antenna that are arranged to face each other, and an alternating magnetic field having a predetermined frequency is transmitted from the transmitting antenna. Transmit (step 900).

  The transmitted alternating magnetic field and the pulse signal generated at the time of magnetization reversal by the magnetic member forming the tag applied to the printing paper by the alternating magnetic field are received via the receiving antenna (step 901), and the in-phase of the received received signals Noise components are removed by a low-pass filter and a high-pass filter (step 902).

  A received signal from which the in-phase noise component has been removed by the low-pass filter and the high-pass filter (hereinafter referred to as “received signal A”) is input to the notch filter, and a sine signal from which the pulse signal component due to magnetization reversal of the magnetic member forming the tag is removed. An alternating magnetic field component of the waveform (hereinafter referred to as “reception signal B”) is extracted (step 903).

  Only the pulse signal due to the magnetization reversal of the magnetic member that forms the tag by differentially amplifying the reception signal A from which the in-phase noise component has been removed by the low-pass filter and the high-pass filter and the reception signal B of the sine waveform extracted by the notch filter is formed. Extract (step 904).

  The extracted pulse signal is counted for a predetermined time (step 905), and the tag of the magnetic member applied to the printing paper is specified from the counting result and the frequency of the alternating magnetic field (step 906).

  Identification information corresponding to the specified combination of types of magnetic members is read (step 907).

  In this way, an alternating magnetic field having a predetermined frequency is applied to the tag applied to the printing paper, the pulse signal generated when the magnetic member forming the tag is reversed in magnetization, and the number of pulses per predetermined time of the detected pulse signal is counted. Then, based on the counted number of pulses and the frequency of the alternating magnetic field, the identification information corresponding to the combination of the types of magnetic members specified by specifying the magnetic members forming the tag attached to the printing paper can be read. it can.

  In this embodiment, the tag information reading method and apparatus according to the present invention can prevent inadvertent document disclosure of contents such as documents and can prevent leakage of confidential information due to inadvertent copying or the like. However, 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. .

FIG. 1 is a block diagram showing a configuration of a main part of an embodiment in which a tag information reading method and apparatus according to the present invention are applied to a printing apparatus. It is a figure which shows an example of the printing paper to which the tag formed with the several magnetic member according to the identification information was provided. It is a figure which shows the transmission signal waveform of the alternating magnetic field transmitted with respect to the printing paper 200 to which the magnetic members 2L202 and 5L205 were provided, and the received signal waveform of the received alternating magnetic field. It is a figure which shows the structure circuit diagram of the principal part comprised so that the tag of the predetermined magnetic material formed in the printing paper could be identified with high precision. FIG. 5 is a diagram showing each signal waveform input or output in the circuit diagram shown in FIG. 4. FIG. 2 is a block diagram illustrating a configuration of a main part of a tag information reading device 40 of the printing apparatus 100 illustrated in FIG. 1. It is a figure which shows an example of the printing paper 630 to which the identification information 631 formed with the several magnetic member was provided. It is a figure which shows an example of each signal waveform for demonstrating operation | movement of the tag information reading apparatus. It is a flowchart which shows the method for the tag information reader 40 concerning this invention shown in FIG. 6 to read the information of the tag which consists of several magnetic members provided to the printing paper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,630 Printing paper 20 Control part 30 Printing part 40 Tag information reading apparatus 50a, 50b Paper feed tray 51a, 51b Paper feed roller 60a, 60b Carry-in roller 61a, 61b Carry-out roller 70 Server 80 Printing instruction terminal 90 Network 100 Printing apparatus 600 Transmission unit 601 Transmission frequency controller 602 Voltage controlled oscillator 603 Frequency converter 604 Transmitter 605 Transmission antenna 610 Reception unit 611 Reception antenna 612 Limiter 613 Low pass filter 614 High pass filter 615 Notch filter 616 Differential amplifier 617 Detector 618 Detection counter 631 Magnetic member 640 Tag information reading control unit

Claims (8)

In a tag information reading method of reading information on a tag based on a detection signal including a pulse signal generated at the time of magnetization reversal of the magnetic member forming the tag by applying a predetermined alternating magnetic field to the tag formed of the magnetic member ,
Selectively removing the pulse signal from the detection signal by a filter;
The detection signal from which the pulse signal is removed and the detection signal before the pulse signal is removed are differentially amplified by a differential amplifier,
A tag information reading method, wherein information on the tag is read based on an output of the differential amplifier.   2. The tag information reading method according to claim 1, wherein the filter is a notch filter having a notch frequency set to a frequency approximately 3 to 9 times the frequency of the alternating magnetic field.   2. The tag information reading according to claim 1, wherein the output of the differential amplifier is counted for a predetermined period, and the tag information is identified from the relationship between the counted number of the pulse signals and the frequency of the alternating magnetic field. Method.   4. The tag information reading method according to claim 3, wherein the alternating magnetic field is intermittently transmitted, and the alternating magnetic field is transmitted in synchronization with the counting. In a tag information reader that reads information on a tag based on a detection signal including a pulse signal generated at the time of magnetization reversal of the magnetic member forming the tag by applying a predetermined alternating magnetic field to the tag formed of the magnetic member ,
A filter that selectively removes the pulse signal from the detection signal;
A differential amplifier for differentially amplifying the detection signal and the output of the filter;
Tag information reading device, comprising: tag information reading means for reading information on the tag based on an output of the differential amplifier. The filter is
The tag information reading device according to claim 5, wherein the tag information reading device is a notch filter having a notch frequency set to a frequency approximately 3 to 9 times the frequency of the alternating magnetic field. The tag information reading means includes
Counting means for counting the output of the differential amplifier for a predetermined period;
6. The tag information reader according to claim 5, further comprising tag information identification means for identifying information on the tag from the relationship between the number of the pulse signals counted by the counting means and the frequency of the alternating magnetic field. . The tag information reader according to claim 5, wherein an alternating magnetic field is intermittently transmitted to the tag formed of the magnetic member, and the counting by the counting means is performed in synchronization with the transmission of the alternating magnetic field. .

Images