JP2007331909A - Double feed detector, its control method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double feed detector capable of avoiding the determination error of double feed in inexpensive constitution; to provide the control method of the double feed detector; and to provide a program. <P>SOLUTION: The double feed detector 12 detecting the presence or absence of double feed in the central part of a paper sheet 1 by detecting the thickness in the central part of the paper sheet 1 fed to a feeding passage with an ultrasonic wave is equipped with two or more thickness detecting means 5 arranged in the width direction almost perpendicularly intersecting with the feeding direction of the paper sheet 1; a reference thickness detecting means 4 detecting the thickness in the central part of the paper sheet 1 as reference thickness; an ultrasonic wave double feeding determination part 13 setting a double feeding detection level based on the reference thickness and the results of double feeding detection detected with ultrasonic waves; and a thickness double feeding determination part 14 detecting the double feeding of the paper sheet 1 based on the reference thickness, the thickness at a plurality of other positions and a double feeding detection level. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a multifeed detection device, a control method therefor, and a program, and more particularly to a multifeed detection device for detecting multifeed when separating and transporting a plurality of sheet-like members one by one using an ultrasonic sensor and The present invention relates to a control method and a program.

  Scanners, printers, copiers, printing machines, ATMs (Automated Teller Machines), and the like are equipped with a mechanism for separating and conveying sheet-like members one by one. However, there may be a possibility that a double feed is performed in which only one sheet-like member is conveyed while a part or the whole of two or more sheet-like members are overlapped. For this reason, the apparatus which conveys a sheet-like member needs the function to detect double feeding of a sheet-like member. Hereinafter, a multi-feed detection device that detects multi-feed of banknotes will be described using a banknote as an example of the sheet-like member.

  FIG. 5 is a diagram schematically showing a configuration of a conventional banknote double feed detection device using ultrasonic waves (see, for example, Patent Document 1).

  In FIG. 5, the multifeed detecting device 110 transmits an ultrasonic wave to the banknote 101 as a sheet-like member to be detected, and an ultrasonic wave received by the ultrasonic wave transmitting unit 102. And a sound wave receiving unit 103.

  As shown in FIG. 5, the ultrasonic wave receiving unit 103 is installed so as to face the ultrasonic wave transmitting unit 102 across the conveyance path of the banknote 101 so that the ultrasonic wave transmitted through the banknote 101 can be received.

  The multifeed detection device 110 further includes a control unit 104 that outputs a 200 kHz pulse signal as an ultrasonic transmission signal, and a drive unit 105 that amplifies the pulse signal output from the control unit 104 and outputs an ultrasonic transmission signal. Is provided. Thereby, the ultrasonic transmission means 102 transmits a 200 kHz ultrasonic wave based on an ultrasonic transmission signal.

  The double feed detection device 110 includes a signal amplifying unit 106 that amplifies the ultrasonic reception signal output from the ultrasonic receiving unit 103.

  When the bill 101 to be transported enters between the ultrasonic transmission unit 102 and the ultrasonic reception unit 103, the ultrasonic wave transmitted from the ultrasonic transmission unit 102 is attenuated before reaching the ultrasonic reception unit 103. The ultrasonic reception signal becomes a very weak signal. Therefore, this ultrasonic reception signal is amplified by the signal amplifying means 106 and raised to a signal voltage at which double feed detection can be determined.

  The double feed detection device 110 includes an AD converter 107 that converts the ultrasonic reception signal (analog signal) amplified by the signal amplification means 106 into a digital signal. Further, the double feed detection device 110 analyzes the digitized ultrasonic reception signal and outputs the analysis result to the control means 104, and a memory for holding each setting value of the double feed detection device 110. Means 109. As a result, the double feed detection device 110 performs a double feed detection operation using the set value held in the storage unit 109.

  Next, the operation of the double feed detection device 110 will be described.

  First, the ultrasonic wave transmitted from the ultrasonic wave transmitting means 102 hits the bill 101 and a part thereof is transmitted. The ultrasonic wave receiving means 103 receives the transmitted wave. The ultrasonic wave receiving means 103 outputs an ultrasonic wave reception signal having a voltage value corresponding to the received intensity of the received ultrasonic wave.

  Next, the signal amplification unit 106 amplifies the ultrasonic reception signal output from the ultrasonic reception unit 103. The A-D converter 107 converts the ultrasonic reception signal amplified by the signal amplification unit 106 into a digital signal, and outputs the digitized ultrasonic reception signal to the signal analysis unit 108. The signal analysis means 108 analyzes the digitized ultrasonic reception signal output from the A / D converter 107. When the control unit 104 determines that the double feed is based on the analysis result of the signal analysis unit 108, the control unit 104 notifies the control unit of the apparatus such as a scanner or the user of the apparatus that the double feed has occurred.

  Here, the double feed detection by the double feed detection device 110 is performed by analyzing the voltage change of the received ultrasonic reception signal by the signal analysis means 108 based on the level determination method. Specifically, first, a double feed determination threshold is set in advance. After that, the ultrasonic wave transmitted from the ultrasonic wave transmitted by the ultrasonic wave transmitting unit 102 and transmitted through the bill 101 is received, and the ultrasonic wave receiving unit 103 outputs an ultrasonic wave reception signal. Here, when the banknote 101 has been multi-fed, the voltage of the output ultrasonic reception signal is higher than the voltage of the ultrasonic reception signal when the banknotes 101 are normally conveyed one by one. The sound wave becomes smaller because it is further attenuated. That is, the voltage of the output ultrasonic reception signal is amplified by the signal amplifying unit 106, and the signal analysis unit 108 detects the double feeding of the bill 101 by comparing it with the above-described double feeding determination threshold.

  FIG. 6 is a diagram schematically showing a configuration of a conventional banknote double feed detection device using infrared rays (see, for example, Patent Document 2).

  In FIG. 6, the multifeed detection device 119 includes an infrared light emitting element 112 such as an infrared light emitting diode (infrared LED) that irradiates the bill 111 as a sheet-like member to be detected with infrared rays. The double feed detection device 119 includes an infrared light receiving element 113 such as an infrared phototransistor that receives infrared light emitted from the infrared light emitting element 112 and outputs an infrared light reception signal.

  As shown in FIG. 6, the infrared light receiving element 113 is installed so as to face the infrared light emitting element 112 with the banknote 111 interposed therebetween so that the infrared light transmitted through the banknote 111 can be received. Here, since the infrared light emitting element 112 and the infrared light receiving element 113 generally have large variations in light emission characteristics and light receiving characteristics, it is necessary to change the double feed determination condition due to individual differences in sensitivity or the like. .

  The double feed detection device 119 further includes a control unit 114 that outputs an analog signal for emitting infrared rays or an ON / OFF signal. The double feed detection device 119 includes a driving unit 115 that causes the infrared light emitting element 112 to emit light based on an analog signal output from the control unit 114 or an ON / OFF signal.

  The double feed detection device 119 includes an AD converter 116 that converts an infrared light reception signal (analog signal) into a digital signal. The double feed detection device 119 analyzes the infrared light reception signal digitized by the A-D converter 116 and outputs the analysis result to the control means 114, and each setting of the double feed detection device 119. Storage means 118 for holding values. As a result, the double feed detection device 119 performs the double feed detection operation using the set value held in the storage unit 118.

  Next, the operation of the double feed detection device 119 will be described.

  First, the infrared light emitted from the infrared light emitting element 112 hits the banknote 111, and a part thereof is transmitted. The infrared light receiving element 113 receives the transmitted light. The infrared light receiving element 113 outputs an infrared light receiving signal having a voltage value corresponding to the intensity of the received infrared light.

  Next, the AD converter 116 converts the infrared light reception signal into a digital signal, and outputs the digitized infrared light reception signal to the signal analysis means 117. The signal analysis unit 117 analyzes the digitized infrared light reception signal output from the A / D converter 116. When the control unit 114 determines that double feeding is performed based on the analysis result of the signal analysis unit 117, the control unit 114 notifies the control unit of the device such as a scanner or the user of the device that double feeding has occurred.

Here, the double feed detection by the double feed detection device 119 is performed by analyzing the change in the voltage of the received infrared light reception signal by the signal analysis means 117 based on the level determination method. Specifically, first, a double feed determination threshold is set in advance. Then, the infrared light receiving element 113 outputs an infrared light receiving signal based on the amount of infrared light transmitted through the bill 111 that has been conveyed among the infrared light emitted by the infrared light emitting element 112. Here, when the banknote 101 has been multi-fed, the voltage of the infrared reception signal that is output is further compared with the voltage of the infrared light reception signal when the banknote 111 is normally conveyed one by one. Decreases due to attenuation. Therefore, by comparing the voltage of the output infrared light reception signal with the above-described multifeed determination threshold in the signal analyzing unit 117, it is possible to detect the multifeed of the banknote 111. Here, the preset multifeed determination threshold value is changed depending on the thickness of the object to be conveyed because the thicker the bill, the more the infrared light is attenuated.
Japanese Patent Laying-Open No. 2005-104682 JP-A-8-48439

  However, the double feed detection method using the double feed detection devices 110 and 119 cannot detect double feed with high accuracy unless a plurality of locations on the bill 101 (111) are irradiated with ultrasonic waves or infrared rays. However, since the ultrasonic transmission means 102 and the ultrasonic reception means 103 are expensive, if a plurality of these pairs are installed in the double feed detection device 110, the cost is greatly increased. On the other hand, since the infrared light emitting element 112 and the infrared light receiving means are inexpensive, even if a plurality of these pairs are installed in the double feed detection device 119, the cost is not greatly increased. However, if multi-feed detection is performed using infrared rays, the multi-feed determination condition must be changed each time the thickness of the transport target medium changes. In particular, when a medium to be transported having various thicknesses is mixedly mounted, reliable double feed detection cannot be performed.

  An object of the present invention is to provide a double feed detection device, a control method thereof, and a program capable of avoiding erroneous determination of double feed with an inexpensive configuration.

  In order to achieve the above object, the double feed detection device according to claim 1 includes a conveying unit that conveys the sheet-like member, and an ultrasonic wave sending unit that emits an ultrasonic wave toward one position of the sheet-like member. The ultrasonic wave transmitting means is disposed opposite to the ultrasonic wave transmitting means across the conveyance path of the sheet-like member, receives the transmitted ultrasonic wave that has passed through the sheet-like member, and outputs an ultrasonic reception signal. In the double feed detecting device, comprising: an ultrasonic receiving means that performs detection; and an ultrasonic double feed detecting means that detects the presence or absence of double feed at the one position of the sheet-like member based on the output ultrasonic reception signal. A plurality of detection sensors arranged in a width direction substantially orthogonal to the conveying direction of the sheet-like member, and a thickness of the sheet-like member at or near the one position is determined as a reference thickness by one of the plurality of detection sensors; age Thickness detecting means for detecting the thickness of a plurality of other positions in the width direction of the sheet-like member by the other of the reference thickness detecting means for detecting and the plurality of detection sensors, the reference thickness and the one of the ones Based on the result of double feed detection at the position, double feed detection level setting means for setting a double feed detection level; based on the reference thickness, the thicknesses of the plurality of other positions, and the double feed detection level; And a double feed detecting means for detecting double feed of members.

  In order to achieve the above object, the double feed detection device according to claim 2 includes a conveying unit that conveys the sheet-like member, and an ultrasonic wave sending unit that emits an ultrasonic wave toward one position of the sheet-like member. The ultrasonic wave transmitting means is disposed opposite to the ultrasonic wave transmitting means across the conveyance path of the sheet-like member, receives the transmitted ultrasonic wave that has passed through the sheet-like member, and outputs an ultrasonic reception signal. In the double feed detecting device, comprising: an ultrasonic receiving means that performs detection; and an ultrasonic double feed detecting means that detects the presence or absence of double feed at the one position of the sheet-like member based on the output ultrasonic reception signal. A plurality of detection sensors arranged in a width direction substantially orthogonal to the conveyance direction of the sheet-like member, and the double-feed detection device is arranged to face the plurality of detection sensors across the conveyance path of the sheet-like member The sheet A light emitting unit configured to emit light toward the one position of the member or the vicinity thereof and the plurality of other positions, wherein the plurality of detection sensors include the light amount of the light emitted from the light emitting unit; A transmitted light amount detecting means for detecting a transmitted light amount through the sheet-like member, and a reference for detecting a transmitted light amount at or near the one position of the sheet-like member as a reference transmitted light amount by one of the plurality of detection sensors; Transmitted light amount detecting means for detecting transmitted light amounts at a plurality of other positions in the width direction of the sheet-like member by other ones of the plurality of detection sensors, the reference transmitted light amount and the super A double feed detection level setting means for setting a double feed detection level based on a result of double feed detection by the sonic double feed detection means; the reference transmitted light amount; the transmitted light amounts at the plurality of other positions; Based on the double feed detection level, characterized in that it comprises a multi-feed detecting means for detecting the double feed of the sheet-like member.

  In order to achieve the above object, a control method according to claim 7 includes: a conveying unit that conveys a sheet-like member; an ultrasonic wave sending unit that emits an ultrasonic wave toward one position of the sheet-like member; An ultrasonic wave that is disposed opposite to the ultrasonic wave transmitting means across the conveyance path of the sheet-like member, receives an ultrasonic wave transmitted through the sheet-like member, and outputs an ultrasonic reception signal. In a control method of a double feed detection device comprising: a sound wave receiving means; and an ultrasonic double feed detection means for detecting the presence or absence of double feed at the one position of the sheet-like member based on the output ultrasonic reception signal. The multi-feed detection device includes a plurality of detection sensors arranged in a width direction substantially orthogonal to a conveyance direction of the sheet-like member, and the control method includes the sheet-like member by one of the plurality of detection sensors. The one of A thickness detection that detects thicknesses at a plurality of other positions in the width direction of the sheet-like member by a reference thickness detection step for detecting a thickness at or near the device as a reference thickness and another of the plurality of detection sensors A multi-feed detection level setting step for setting a multi-feed detection level based on the reference thickness and the result of multi-feed detection at the one position; the reference thickness; the thicknesses of the plurality of other positions; And a double feed detection step of detecting double feed of the sheet-like member based on a double feed detection level.

  According to the present invention, the multi-feed detection device detects the presence or absence of multi-feed at one position of the sheet-like member conveyed by the conveying means by ultrasonic waves, and the width direction substantially orthogonal to the conveyance direction of the sheet-like member. A plurality of detection sensors arranged in a line, and one of the plurality of detection sensors detects the thickness at the one position or the vicinity thereof as a reference thickness, and the other of the plurality of detection sensors detects a sheet shape. Detect the thickness of a plurality of other positions in the width direction of the member, set the double feed detection level based on the reference thickness and the result of double feed detection by the ultrasonic wave, the reference thickness, the thickness of the plurality of other positions, Since the double-feed of the sheet-like member is detected based on the double-feed detection level, if it is determined that only a part of the sheet-like member overlaps, a seal-like member or sticky paper is intentionally pasted on the sheet-like member. Give deemed are, thereby, it is possible to avoid erroneous determination of the double feed inexpensive configuration.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram schematically showing a configuration of a double feed detection device according to an embodiment of the present invention.

  In FIG. 1, a double feed detection device 12 is a device that detects double feed of a paper 1 that has been transported to a transport path (not shown), and transmits ultrasonic waves toward the center of the paper 1. And an ultrasonic receiver 3 disposed opposite to the ultrasonic transmitter 2 across the paper 1 conveyance path. Thereby, the ultrasonic wave receiver 3 can receive the transmitted wave that has passed through the paper 1 among the ultrasonic waves transmitted from the ultrasonic wave transmitter 2.

  The ultrasonic receiver 3 outputs an output voltage (ultrasonic reception signal) that changes according to the received intensity of the received ultrasonic wave.

  In the present embodiment, the detection target of double feed is paper 1, but it is not limited to paper as long as it is conveyed after a plurality of sheet-like members are separated. For example, it may be a case where a film or banknote is conveyed instead of the paper 1.

  Further, when the paper 1 is transported to the transport path, the ultrasonic wave transmitted through the paper 1 is received by the ultrasonic receiver 3, but when the paper 1 is not transported to the transport path, the ultrasonic transmitter The ultrasonic wave transmitted by 2 is received by the ultrasonic receiver 3 as it is.

  The multi-feed detection device 12 is further arranged with a plurality of reference thickness detection means 4 for detecting the thickness of the central portion of the paper 1 and a direction substantially orthogonal to the conveyance direction of the paper 1 (hereinafter referred to as “width direction”). And thickness detecting means 5 for detecting the thickness of a plurality of locations on the paper 1.

  Here, the ultrasonic transmitter 2 transmits ultrasonic waves to the central portion of the paper 1, and the reference thickness detection means 4 is configured to detect the thickness of the central portion of the paper 1. However, if the location where the ultrasonic transmitter 2 transmits ultrasonic waves to the paper 1 is the same as or close to the location where the reference thickness detection means 4 detects the thickness, the location is limited to the central portion of the paper 1. is not. The voltage values of the reference thickness detection signal output from the reference thickness detection means 5 and the thickness detection signal output from the thickness detection means 6 are proportional to the thickness of the paper 1, but the present invention is limited to this. It is not a thing.

  In the present embodiment, the reference thickness detection means 4 and the thickness detection means 5 are sensors that detect a mechanical displacement that occurs in a member that contacts the paper 1, but may be sensors that can detect the thickness of the paper 1. It is not limited to this. For example, a sensor that uses reflected light on the paper 1 may be used.

  In addition, the double feed detection device 12 controls the entire device itself, generates a 200 KHz ultrasonic pulse signal, and amplifies the ultrasonic pulse signal generated by the control unit 6 to generate an ultrasonic transmission signal. And a drive means 7 for driving the ultrasonic transmitter 2 by outputting.

  Accordingly, the ultrasonic transmitter 2 transmits a 200 kHz ultrasonic wave based on the ultrasonic transmission signal. Here, the ultrasonic pulse signal generated by the control means 6 is a burst wave that transmits a pulse signal of 200 kHz for several cycles at a rate of once every several ms.

  Furthermore, the double feed detection device 12 includes a signal amplifying unit 8 that amplifies the ultrasonic reception signal output from the ultrasonic receiver 3.

  The ultrasonic wave transmitted from the ultrasonic transmitter 2 is greatly attenuated when passing through the paper 1 and becomes weak before reaching the ultrasonic receiver 3. That is, if the ultrasonic reception signal output from the ultrasonic receiver 3 is used as it is, the difference in signal intensity between when the paper 1 is conveyed by only one sheet and when the paper 1 is double-fed together with other paper is obtained. This is because amplification is necessary because it is small and cannot reliably detect double feeding.

  The double feed detection device 12 further includes an A / D converter 9 that converts a received analog signal into a digital signal, a signal analysis unit 10 that performs signal analysis of the digital signal converted by the A / D converter 9, and Storage means 11 for holding the set values.

  Here, the analog signal converted by the A / D converter 9 includes the ultrasonic reception signal amplified by the signal amplifying unit 8, the reference thickness detection signal from the reference thickness detection unit 4, and the thickness from the thickness detection unit 5. There is a detection signal.

  The storage unit 11 holds setting values such as the number of ultrasonic transmission pulses, the amplitude of the ultrasonic transmission signal, the ultrasonic transmission frequency, the ultrasonic reception signal acquisition time, the ultrasonic double feed detection level, and the thickness double feed detection level.

  Further, the control unit 6 transmits various setting values held in the storage unit 11 to the signal analysis unit 10, and the signal analysis unit 10 performs a multifeed detection process described later based on the transmitted various setting values. .

  Next, the double feed detection process in the signal analysis means 10 will be specifically described.

  The signal analysis unit 10 includes an ultrasonic double feed determination unit 13 and a thickness double feed determination unit 14.

  The ultrasonic double feed determination unit 13 determines the presence or absence of double feed in the central portion of the paper 1 based on the digitized ultrasonic reception signal. The thickness double feed determination unit 14 calculates the thickness of the paper 1 when the double feed is not performed based on the determination result and the digitized reference thickness detection signal, and the calculated thickness and digitized value. Based on the thickness detection signal, the presence / absence of double feeding in the width direction of the paper 1 is determined.

  Specifically, the ultrasonic double feed determination unit 13 is configured to detect the ultrasonic double feed detection level in which the voltage of the digitized ultrasonic reception signal is held in the storage unit 11 acquired via the control unit 6. When it is less than the value of (threshold value S1), it is detected that double feeding has occurred. On the other hand, when the voltage of the digitized ultrasonic reception signal is equal to or higher than the threshold value S1, it is detected that there is no double feed.

  Here, the first reception signal voltage when only one sheet 1 exists between the ultrasonic transmitter 2 and the ultrasonic receiver 3, and the paper between the ultrasonic transmitter 2 and the ultrasonic receiver 3. The second received signal voltage when two 1s are present is measured in advance at the time of factory shipment or the like. The measured average value of the first reception signal voltage value and the second reception signal voltage value is held in the storage unit 11 as the ultrasonic double feed detection level (threshold value S1).

  It should be noted that the second received signal voltage value is substantially the same as the value at the time of no signal regardless of the material and thickness of the paper 1 because the ultrasonic wave transmitted through two or more sheets is very weak. Sometimes it becomes. Therefore, in such a case, the value of the threshold value S1 is not the average value of the first received signal voltage value and the second received signal voltage value, but the second received signal is higher than the first received signal voltage value. When the value is closer to the voltage value, the double feed detection can be performed more reliably.

  Next, the thickness double feed determination unit 14 in the signal analysis unit 10 will be specifically described.

  FIG. 2 is a flowchart showing a procedure of double feed determination processing by the double feed detection device 12 of FIG.

  In FIG. 2, first, the thickness double feed determination unit 14 calculates a thickness double feed determination threshold based on the presence / absence of double feed in the ultrasonic double feed determination unit 13 and the voltage value of the digitized reference thickness detection signal. (Step S301).

  Specifically, when the ultrasonic double feed determination unit 13 determines that there is no double feed, a value obtained by multiplying the voltage value of the reference thickness detection signal by 1.5 is calculated as the thickness double feed determination threshold. On the other hand, when the ultrasonic double feed determination unit 13 determines that double feed has occurred, a value obtained by multiplying the voltage value of the reference thickness detection signal by 0.75 is calculated as the thickness double feed determination threshold.

  Here, in order to calculate the thickness double feed determination threshold, a value of 1.5 was used as a coefficient when no double feed occurred, and a value of 0.75 was used as a coefficient when double feed occurred. It is essential to use different coefficients depending on the presence or absence of double feeding, and the coefficients are not limited to these values.

  Returning to FIG. 2, the thickness double feed determination unit 14 next determines the overlap at multiple locations in the width direction of the paper 1 based on the thickness double feed determination threshold, the voltage value of the reference thickness detection signal, and the voltage value of the thickness detection signal. The presence or absence of sending is detected (step S302).

  Specifically, the thickness double feed determination unit 14 determines whether the detected voltage value of any thickness detection signal is equal to or greater than the thickness double feed determination threshold value at the position where the thickness detection unit 5 is installed. Judge that double feed is occurring. On the other hand, when the detected voltage value of each thickness detection signal is less than the value of the thickness double feed determination threshold value, it is determined that double feed has not occurred.

  Thereafter, the thickness double feed determination unit 14 holds the ratio (double feed determination ratio) of the locations where double feed has occurred as a result of the detection in the storage unit 11 acquired via the control unit 6. It is determined whether or not the thickness is higher than the thickness double feed detection level (threshold value S2) (step S303). As a result, when the double feed determination ratio is equal to or greater than the threshold value S2 (30%), it is determined that a double feed has actually occurred (step S304), and this process is terminated. On the other hand, as a result of this detection, when the double feed determination ratio is less than 30%, it is determined that a seal-like member or a sticky note paper is pasted on the paper 1 and that there is actually no double feed. (Step S305). Thereby, it is possible to avoid erroneous determination of double feeding with an inexpensive configuration.

  Here, in the present embodiment, the value of the threshold value S2 is set to 30%, but this is only an example and may be changed to another value. Further, as in the present embodiment, instead of determining the presence or absence of actual double feed using the double feed determination ratio, the double feed portion is determined based on the position information of the location where it is detected that double feed has occurred. The length may be obtained, and whether or not there is actual double feeding may be determined based on whether the length is larger than the threshold value S2.

  FIG. 3 is a diagram used for explaining the multi-feed determination process in FIG. 2 when the paper 1 on which the sticky note paper is intentionally pasted is conveyed.

  As shown in FIG. 3, the sticky note 15 is attached to the left end of the paper 1 as viewed in the drawing.

  In addition, since the width of the sticky note 15 is less than half the width of the paper 1, the ultrasonic double feed determination unit 13 determines the weight of the paper 1 based on the ultrasonic reception signal received by the ultrasonic receiver 3. Judge that there is no sending. Based on this determination result, the thickness double feed determination unit 14 calculates a value obtained by multiplying the voltage value of the reference thickness detection signal received by the reference thickness detection unit 4 by 1.5 as the thickness double feed determination threshold.

  In the present embodiment, four thickness detecting means 5 are arranged on both sides of the reference thickness detecting means 4 arranged at the center in the width direction. Also, as shown in FIG. 3, the thickness detection means 5 determines that the voltage of the received thickness detection signal is equal to or higher than the double feed determination threshold, because the sticky note 15 is attached to the paper 1. It is two which detects the thickness of a part. Further, there are six thickness detecting means 5 existing within the range of the paper width, and seven including the reference thickness detecting means 4 added thereto are effective.

  That is, in the example of FIG. 3, the above-described double feed determination ratio is about 28.6%, which is less than the threshold value S2 (30%). Judge that it has not occurred.

  FIG. 4 is a diagram schematically showing a configuration of a modified example of the multifeed detection device 12.

  The double feed detection device 19 of FIG. 4 is basically the same in configuration as the double feed detection device 12, and the same components are denoted by the same reference numerals and redundant description is omitted, and different components are described below. Will be described.

  In the double feed detection device 19 of FIG. 4, a plurality of reference transmitted light amount detection means 16 for detecting the thickness of the central portion of the paper 1 and a plurality of them in the width direction are arranged instead of the reference thickness detection means 4 and the thickness detection means 5 in FIG. 1. It has a transmitted light amount detection means 17 that is arranged and discriminates double feeding at a plurality of locations on the paper 1. In addition, the signal analysis unit 10 in FIG. 1 includes a transmitted light amount double feed determination unit 18 instead of the thickness double feed determination unit 14. The storage unit 11 holds a transmitted light amount double feed detection level (threshold) instead of the thickness double feed detection level.

  The reference transmitted light amount detection means 16 is similar to the thickness detection means 4 in that the ultrasonic wave transmitted from the ultrasonic wave transmitter 2 and received by the ultrasonic wave receiver 3 is transmitted in order to detect double feeding of the paper 1 or As long as the thickness in the vicinity is detected, the detection position is not limited to the central portion.

  The reference transmitted light amount detection means 16 and the transmitted light amount detection means 17 are infrared light receiving elements, and infrared light emitting elements 16a and 17a (not shown) are arranged at positions facing the paper 1 to be conveyed with the paper 1 being sandwiched therebetween. Thereby, infrared rays are emitted from the infrared light emitting elements 16a and 17a, and the infrared rays transmitted through the paper 1 are received by the reference transmitted light amount detecting means 16 and the transmitted light amount detecting means 17. The reference transmitted light amount detection means 16 and the transmitted light amount detection means 17 may be changed to a configuration that detects transmitted light other than infrared light.

  Further, the double feed detection device may be incorporated in an image reading device having an image reading unit including a line sensor and illumination. In this case, the reference transmitted light amount detection means 16 and the transmitted light amount detection means 17 are changed to those that receive visible light, and are installed on the opposite side of the image reading unit with the paper 1 to be image read in between. You may change to the structure which receives the transmitted light of this.

  In addition, the double feed detection device 19 may further include a cold cathode tube that irradiates the paper 1 on the opposite side of the reference transmitted light amount detection unit 16 and the transmitted light amount detection unit 17 with the paper 1 interposed therebetween. In this case, the reference transmitted light amount detection means 16 and the transmitted light amount detection means 17 may receive the transmitted light transmitted through the paper 1 out of the visible light irradiated from the cold cathode tube.

  In addition, the double feed detection device 19 is not shown as a pair on the same side as the reference transmitted light amount detection means 16 and the transmitted light amount detection means 17 as the infrared light receiving element with respect to the conveyed paper 1. Infrared light emitting elements 16b and 17b may be provided. In addition, infrared light receiving elements 16c and 17c (not shown) that are paired with the infrared light emitting elements 16a and 17a may be provided on the same side as the infrared light emitting elements 16a and 17a.

  In this case, of the infrared light emitted by the infrared light emitting elements 16 b and 17 b, the light reflected by the surface of the paper 1 is received by the reference transmitted light amount detecting means 16 and the transmitted light amount detecting means 17. As a result, the density of the surface of the paper 1 with respect to infrared rays is detected. Of the infrared light emitted by the infrared light emitting elements 16a and 17a, the light reflected by the back surface of the paper 1 is received by the infrared light receiving means 16c and 17c. As a result, the density of the back surface of the paper 1 with respect to infrared light is detected. Thereafter, the transmitted light amount detected by the reference transmitted light amount detection means 16 and the transmitted light amount detection means 17 is corrected based on the detected density of the front and back surfaces of the paper 1. Thereby, the value of the detected transmitted light amount can be appropriately corrected.

  Here, the light emission timings of the infrared light emitting elements 16a and 17a and the light emission timing of the infrared light emitting elements 16b and 17b emit light alternately. As a result, the reference transmitted light amount detection means 16 and the transmitted light amount detection means 17 are configured so that the amount of light transmitted through the paper 1 out of the light from the infrared light emitting elements 16a and 17a and the paper out of the light from the infrared light emitting elements 16b and 17b. Each of the amounts of light reflected by 1 can be reliably detected.

  Since the transmitted light amount is very small compared to the reflected light amount, only the infrared light emitting elements 16b and 17b are switched on / off, and the light amount acquired when the light is OFF is acquired when the transmitted light amount is ON. The amount of light may be acquired as the amount of reflected light.

  Next, the transmitted light amount multi-feed determining unit 18 of the signal analyzing unit 10 according to this modification will be specifically described.

  First, the transmitted light amount multi-feed determination unit 18 calculates a transmitted light amount multi-feed determination threshold based on the presence / absence of multi-feed in the ultrasonic multi-feed determination unit 13 and the voltage value of the digitized reference transmitted light amount detection signal. .

  Specifically, when the ultrasonic multifeed determination unit 13 determines that there is no multifeed, a value obtained by multiplying the voltage value of the reference transmitted light amount detection signal by 1.5 is calculated as the transmitted light amount multifeed determination threshold. On the other hand, when the ultrasonic multifeed determination unit 13 determines that multifeed has occurred, a value obtained by multiplying the voltage value of the reference transmitted light amount detection signal by 0.75 is calculated as the transmitted light amount multifeed determination threshold.

  Here, in order to calculate the transmitted light amount multi-feed determination threshold, a value of 1.5 was used as a coefficient when no multi-feed occurred, and a value of 0.75 was used as a coefficient when multi-feed occurs. However, it is essential to use different coefficients depending on the presence or absence of double feeding, and the coefficients are not limited to these values.

  Next, the transmitted light amount multi-feed determining unit 13 multi-feeds at a plurality of locations in the width direction of the paper 1 based on the transmitted light amount multi-feed determination threshold, the voltage value of the reference transmitted light amount detection signal, and the voltage value of the transmitted light amount detection signal. The presence or absence of is detected.

  Specifically, the transmitted light amount multi-feed determining unit 13 is provided with the transmitted light amount detecting means when the voltage value of any detected transmitted light amount detection signal is less than the transmitted light amount multi-feed determination threshold value. Detects that double feed occurs at the specified position. On the other hand, when the detected voltage value of each transmitted light amount detection signal is equal to or greater than the transmitted light amount double feed determination threshold value, it is detected that there is no double feed.

  Thereafter, the transmitted light amount multi-feed determination unit 13 holds the ratio (double feed determination ratio) of the locations where double feed has occurred as a result of the detection in the storage unit 11 acquired via the control unit 6. It is determined whether or not the transmitted light amount double feed detection level (threshold value S2 ′) is exceeded. As a result, when the double feed determination ratio is equal to or greater than the threshold S2 '(30%), it is determined that double feed has actually occurred. On the other hand, as a result of this detection, when the double feed determination ratio is less than 30%, it is determined that a seal-like member or a sticky note paper is pasted on the paper 1 and that there is actually no double feed. . This can prevent erroneous determination as double feeding.

  Here, in the present embodiment, the value of the threshold value S2 'is set to 30%, but this is only an example and may be changed to another value. Further, as in the present embodiment, instead of determining the presence or absence of actual double feed using the double feed determination ratio, the double feed portion is determined based on the position information of the location where it is detected that double feed has occurred. The length may be obtained, and whether or not there is actual double feeding may be determined based on whether or not the length is larger than the threshold value S2 ′.

  Another object of the present invention is to supply a storage medium storing software program codes for realizing the functions of the above-described embodiments to a system or apparatus, and the computer of the system or apparatus (or CPU, MPU, or the like). Is also achieved by reading and executing the program code stored in the storage medium.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code and the storage medium storing the program code constitute the present invention. .

  Examples of the storage medium for supplying the program code include a floppy (registered trademark) disk, a hard disk, a magneto-optical disk, a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, a DVD-RAM, and a DVD. An optical disc such as RW or DVD + RW, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used. Alternatively, the program code may be downloaded via a network.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (Operating System) running on the computer based on the instruction of the program code Includes a case where the functions of the above-described embodiments are realized by performing part or all of the actual processing.

  Furthermore, after the program code read from the storage medium is written to a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the expanded function is based on the instruction of the program code. This includes a case where a CPU or the like provided on the expansion board or the expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within the scope not departing from the gist of the present invention.

It is a figure which shows schematically the structure of the double feed detection apparatus which concerns on embodiment of this invention. It is a flowchart which shows the procedure of the double feed judgment process by the double feed detection apparatus of FIG. It is a figure used for demonstrating the double feed judgment process of FIG. 2 when the paper in which the sticky note paper was intentionally stuck is conveyed. It is a figure which shows roughly the structure of the modification of a double feed detection apparatus. It is a figure which shows roughly the structure of the conventional multifeed detection apparatus of the banknote using an ultrasonic wave. It is a figure which shows schematically the structure of the conventional multi-feed detection apparatus of the banknote using infrared rays.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Paper 2 Ultrasonic transmitter 3 Ultrasonic receiver 4 Reference | standard thickness detection means 5 Thickness detection means 6 Control means 7 Drive means 8 Signal amplification means 9 AD converter 10 Signal analysis means 11 Storage means 12 Double feed detection apparatus 13 Ultrasonic double feed determination unit 14 Thickness double feed determination unit 15 Sticky note 16 Reference transmitted light amount detection unit 17 Transmitted light amount detection unit 18 Transmitted light amount multiple feed determination unit 19 Double feed detection device

Claims (8)

A conveying means for conveying the sheet-like member, an ultrasonic wave transmitting means for sending an ultrasonic wave toward one position of the sheet-like member, and the ultrasonic wave sending means across the conveyance path of the sheet-like member. Ultrasonic wave receiving means for receiving the transmitted ultrasonic wave that has passed through the sheet-like member and outputting an ultrasonic wave reception signal, and the sheet based on the output ultrasonic wave reception signal In the double feed detection device comprising ultrasonic double feed detection means for detecting the presence or absence of double feed at the one position of the member,
A plurality of detection sensors arranged in a width direction substantially orthogonal to the conveying direction of the sheet-like member;
Reference thickness detection means for detecting the thickness of the sheet-like member at or near the one position as a reference thickness by one of the plurality of detection sensors;
Thickness detection means for detecting the thickness of a plurality of other positions in the width direction of the sheet-like member by another of the plurality of detection sensors;
Double feed detection level setting means for setting a double feed detection level based on the reference thickness and the result of double feed detection by the ultrasonic double feed detection means;
A double feed detection device comprising: double feed detection means for detecting double feed of the sheet-like member based on the reference thickness, the thicknesses of the plurality of other positions, and the double feed detection level. A conveying means for conveying the sheet-like member, an ultrasonic wave transmitting means for sending an ultrasonic wave toward one position of the sheet-like member, and the ultrasonic wave sending means across the conveyance path of the sheet-like member. An ultrasonic receiving means for receiving the transmitted ultrasonic wave transmitted through the sheet-like member and outputting an ultrasonic reception signal; and the sheet based on the output ultrasonic reception signal In the double feed detection device comprising ultrasonic double feed detection means for detecting the presence or absence of double feed at the one position of the member,
A plurality of detection sensors arranged in a width direction substantially orthogonal to the conveying direction of the sheet-like member;
The multi-feed detection device is arranged to face the plurality of detection sensors across a conveyance path of the sheet-like member, and is directed to the one position of the sheet-like member or the vicinity thereof and the plurality of other positions. Further comprising a light emitting means for emitting light,
The plurality of detection sensors are transmitted light amount detection means for detecting the amount of light transmitted through the sheet-like member out of the amount of light emitted by the light emitting means,
A reference transmitted light amount detecting means for detecting a transmitted light amount at or near the one position of the sheet-like member as a reference transmitted light amount by one of the plurality of detection sensors;
Transmitted light amount detection means for detecting transmitted light amounts at a plurality of other positions in the width direction of the sheet-like member by another of the plurality of detection sensors;
Double feed detection level setting means for setting a double feed detection level based on the result of double feed detection by the reference transmitted light amount and the ultrasonic double feed detection means;
A double feed detection device comprising: a double feed detection unit that detects double feed of the sheet-like member based on the reference transmitted light amount, the transmitted light amount of the plurality of other positions, and the double feed detection level. .   3. The multifeed detection apparatus according to claim 2, wherein the light emitting means is a cold cathode tube.   3. The multifeed detection device according to claim 2, wherein the light emitting means is a plurality of infrared light emitting elements, and the plurality of detection sensors are a plurality of infrared light receiving elements. A plurality of other infrared light receiving elements which are on the same side as the plurality of infrared light emitting elements with respect to the sheet-like member and are paired with each other, and the same side as the plurality of infrared light receiving elements with respect to the sheet-like member And further comprising a plurality of other infrared light emitting elements paired with each other,
Among the infrared rays emitted from the plurality of other infrared light emitting elements, the plurality of infrared light receiving elements receive light reflected by the surface of the conveyed sheet-like member, and the density of the surface of the sheet-like member is determined. First density detecting means for detecting;
Among the infrared light emitted from the plurality of infrared light emitting elements, the plurality of other infrared light receiving elements receive light reflected by the back surface of the conveyed sheet-like member, and the density of the back surface of the sheet-like member is determined. A second density detecting means for detecting;
5. The multifeed according to claim 4, further comprising: a correction unit that corrects a light amount detected by the transmitted light amount detection unit based on the detected surface density of the sheet-like member and the density of the back surface. Detection device.   The light emitting unit is an image reading unit that reads an image formed on the sheet-like member by irradiating light on the surface of the conveyed sheet-like member and receiving reflection of the light. The double feed detection device according to claim 2. A conveying means for conveying the sheet-like member, an ultrasonic wave transmitting means for sending an ultrasonic wave toward one position of the sheet-like member, and the ultrasonic wave sending means across the conveyance path of the sheet-like member. Ultrasonic wave receiving means for receiving the transmitted ultrasonic wave that has passed through the sheet-like member and outputting an ultrasonic wave reception signal, and the sheet based on the output ultrasonic wave reception signal In a control method of a double feed detection device comprising ultrasonic double feed detection means for detecting the presence or absence of double feed at the one position of the shaped member,
The multi-feed detection device includes a plurality of detection sensors arranged in a width direction substantially orthogonal to a conveyance direction of the sheet-like member,
The control method is:
A reference thickness detection step of detecting, by one of the plurality of detection sensors, a thickness of the sheet-like member at or near the one position as a reference thickness;
A thickness detecting step of detecting a thickness of a plurality of other positions in the width direction of the sheet-like member by another of the plurality of detection sensors;
Based on the result of double feed detection by the reference thickness and the ultrasonic double feed detection means, a double feed detection level setting step for setting a double feed detection level;
A control method comprising: a double feed detection step of detecting double feed of the sheet-like member based on the reference thickness, the thicknesses of the plurality of other positions, and the double feed detection level.   A program for causing a computer to execute the control method according to claim 7.

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