JP3993366B2

JP3993366B2 - Foreign matter detection device for paper sheets

Info

Publication number: JP3993366B2
Application number: JP2000174056A
Authority: JP
Inventors: 政夫小浜
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 2000-06-09
Filing date: 2000-06-09
Publication date: 2007-10-17
Anticipated expiration: 2020-06-09
Also published as: JP2001351141A

Description

【０００１】
【発明の属する技術分野】
本発明は、たとえば、搬送される紙葉類に付着するテープや紙片などの異物を検知する紙葉類の異物検知装置に関する。
【０００２】
【従来の技術】
従来、たとえば、ベルトに挟持して搬送される紙葉類の異物検知では、軸を固定した固定ローラと上下移動が可能な支持構造の可動ローラとを対向させて一対として搬送路に配設し、両ローラ間を紙葉類が通過するときの可動ローラの変位量を厚みとして検知し、厚みの部分的な変化を異物としている。
【０００３】
また、紙葉類の幅方向の異物を検知するには、搬送方向に対して直交方向に複数のローラ対を並設して厚みの分布を検知し、幅方向の厚み変化から異常な厚み部分を異物として検知している。
【０００４】
さらに、超音波などの音波を発生する送波器と音波を受ける受波器とを紙葉類の搬送路を挟んで配設し、紙葉類を透過する音波の量を受波器で検知し、紙葉類の厚みに応じた透過音波量よりも小さくなった場合を異物として検知したり、紙葉類の複数枚重なりの検知をしている。
【０００５】
【発明が解決しようとする課題】
ところが、可動ローラの変位によって紙葉類の厚さを検知する方式では、可動ローラがある程度の重量を持つため、走行する紙葉類の先端突入や後端の抜け、あるいは、テープを貼付したような急激な変化に対する追従性が悪く、検知速度に限界がある。
【０００６】
また、ローラ対を複数個並べて紙葉類の幅方向の厚み分布を検知する場合には、ローラ支持部材などのためにローラ対を密着して設置することができず、紙葉類の幅方向の分解能をあげることが難しい。
【０００７】
さらには、紙葉類が走行中に厚み方向に揺動すると、その揺動を可動ローラの変位量として測定するため、精度が悪くなるなどの問題がある。また、製造上からは、ローラやローラ支持部材の加工精度をあげて、ローラ回転時のがたを小さく押さえて測定精度を確保するため、製造価格が高価となる。
【０００８】
一方、超音波などの音波を用いる方式では、送波器から出力される音波はその進行方向に広がりを持つため、単位面積当たりの音波量は小さくなる。そのため、受波器の出力信号も小さくなってＳ／Ｎが低下し、異物の検知限界を上げることができない。
【０００９】
音波の広がりを小さくするために、送波器と受波器とを近接して設置すると、紙葉類に対して直角に音波を照射することになる。紙葉類に対して直角に音波を当てると、紙葉類からの反射音波と送波器からの照射音波とが干渉し、紙葉類が揺動して搬送されると、送波器との距離が変化するため、干渉波に強弱が生じ、紙葉類の表面に到達する音波にも強弱が生じるため、安定した透過音波を得ることができない。
【００１０】
このような干渉を避けるため、たとえば、特開平６−７２５９１号公報の超音波式２枚検知方法では、紙葉類の厚みが１枚か２枚かを検知する手段として、紙葉類に対して斜めに音波を照射することにより、紙葉類からの反射音波が送波器に入射しないようにしているが、斜めに音波を照射することにより、送波器と受波器との間の距離が長くなるため、音波の広がりは避けられず、単位面積当たりの音波エネルギは小さくなる。したがって、この方式を異物検知に適用した場合、異物の検知限界が下がり、より小さな異物を検知することが困難である。
【００１１】
そこで、本発明は、搬送される紙葉類に非接触で異物を検知でき、異物の検知限界を向上させるとともに、紙葉類の幅方向に分布する異物の検知をも可能とし、紙葉類の厚み方向の揺動による影響を受けることなく、安定して異物検知できる紙葉類の異物検知装置を提供することを目的とする。
【００１２】
【課題を解決するための手段】
上記目的を達成するため、本発明においては、音波の送波器と受波器とを搬送される紙葉類を挟むように配設し、送波器および受波器、あるいは、送波器のみに対して音波ガイドを設けるもので、この音波ガイドは紙葉類に対向する端部の断面形状が扁平状をなしており、その端部の長径部を紙葉類の幅方向（搬送方向と直交方向）と平行にして設置するものであり、さらに、送波器は紙葉類の一方の面に対して斜め方向から音波を照射するように設け、受波器は送波器と直接対向しないように紙葉類の他方の面に対して直交する方向に設けるものである。
【００１３】
送波器から出力された音波は音波ガイドに沿って収束され、扁平状の音波束として紙葉類の表面に照射される。紙葉類に照射された音波束の一部は紙葉類の表面で反射され、一部は紙葉類を透過する。紙葉類に照射する音波束は、上述したように音波ガイドの先端で扁平状に絞っているため、紙葉類の表面からの反射音波が送波器に逆進入してくる量が少なくなり、紙葉類の揺動による干渉が小さくなる。
【００１４】
紙葉類を透過した音波は、紙葉類の繊維によって乱反射するため、音波束の進行線上を中心にある広がりを持つ。したがって、この紙葉類を透過した散乱音波を受波器で捉えることにより、透過音波の強弱を知ることができる。
【００１５】
受波器で透過音波を受ける場合、送波器と同じように受波器に音波ガイドを設置して、送波器の音波ガイドの先端部に対向して中心線を概略合わせて設置すれば、限られた面積の透過音波を捉えるため、紙葉類上の異物による透過音波の変化を感度よく捉えることができる。
【００１６】
また、受波器に音波ガイドを設けずに紙葉類のより近くに設置して、空中での透過音波の減衰を小さくして散乱音波を検知してもよい。この場合、音波が透過する近傍に、紙葉類に対して直角に向い合わせて設置してもよい。
【００１７】
このように構成した本発明に係る紙葉類の異物検知装置では、送波器からの音波を音波ガイドによって収束して紙葉類に照射するため、音波ガイドの先端扁平部の端辺の長さにより小さい異物に対しても感度よく音波の減衰を検知することができる。また、音波ガイドにより音波を収束しているため、送波器を並べて複数個設置する場合、隣接するお互いの送波器からの音波の干渉が小さく、近接させることができる。したがって、紙葉類の幅方向に送波器と受波器との対を複数設置して幅全体の異物検知を行なう場合、装置全体の小形化が可能となる。
【００１８】
このようにして非接触、高感度、小形の紙葉類の異物検知装置が実現できるものである。
【００１９】
【発明の実施の形態】
以下、本発明の実施の形態について図面を参照して説明する。
【００２０】
まず、第１の実施の形態について説明する。
【００２１】
図１は、第１の実施の形態に係る紙葉類の異物検知装置の構成を概略的に示すものである。図１において、１は紙葉類であり、図示しない搬送ベルトなどにより挟持されて図示矢印Ｂ方向に搬送されるものとする。Ｑは紙葉類１に付着したテープや紙片などの異物である。２は紙葉類１に対して超音波を照射する送波器、３は紙葉類１を透過した音波を受ける受波器であり、これらは搬送される紙葉類１を間にして相対向配設されている。この場合、送波器２および受波器３は、搬送される紙葉類１の表面に対して斜め方向から音波を照射し、その透過音波を受けるように相対向して設置されている。４は送波器２から照射される音波をガイドする音波ガイド、５は紙葉類１を透過した音波を受波器３へガイドする音波ガイドである。ここに、送波器２から照射される音波をＡ、紙葉類１の表面で反射する音波をＡ１、紙葉類１を透過して散乱する音波をＡ２とする。
【００２２】
音波ガイド４，５は、たとえば、図２に示すような断面形状をなしている。すなわち、音波ガイド４の送波器２側のＸ１−Ｘ１線に沿う断面形状は図２（ａ）のようにほぼ円形状、音波ガイド４の紙葉類１側（先端部）のＸ２−Ｘ２線に沿う断面形状は図２（ｂ）のように扁平状となっており、その扁平部の長径部が紙葉類１の幅方向（搬送方向Ｂと直交方向）と平行になるように、音波ガイド４が設置されている。なお、受波器３側の音波ガイド５も同様の構造および配置となっている。
【００２３】
図３は、上記のように構成された異物検知装置の電気回路を示すものである。２１は発振回路で、たとえば、２０ｋＨｚ〜５０ｋＨｚの帯域を持った交流電圧を発生する。２２はパワーアンプで、発振回路２１からの交流電圧を増幅し、その増幅出力で送波器２を駆動する。２３はアンプで、受波器３の出力信号を増幅する。２４は発振回路２１の周波数を中心周波数とするバンドパスフィルタ（ＢＰＦ）で、アンプ２３の出力信号から雑音成分を除去する。２５は整流回路で、バンドパスフィルタ２４の出力信号を直流信号に変換する。２６は比較回路で、整流回路２５の出力信号を比較基準設定回路２７で設定された比較基準値と比較することにより、異物有無信号を出力する。
【００２４】
このような構成において、発振回路２１から出力される交流電圧はパワーアンプ２２で増幅され、その増幅出力で送波器２が駆動される。紙葉類１を透過した音波は、受波器３で電気信号に変換されて透過音波信号となり、アンプ２３で増幅されてバンドパスフィルタ２４に送られ、ここで雑音成分を除去された後、整流回路２５で直流信号に変換され、比較回路２６に送られる。比較回路２６は、整流回路２５の出力信号を比較基準設定回路２７で設定された比較基準値と比較し、整流回路２５の出力信号が比較基準値よりより低い電圧値になったとき、異物が有りとして異物有り信号を出力するものである。
【００２５】
次に、作用について説明する。
【００２６】
図１に示すように、送波器２を紙葉類１に対し音波の送波軸が斜めになるように設置し、送波器２に音波ガイド４を取付けて音波Ａを照射すると、音波Ａは紙葉類１の表面で反射されて反射音波Ａ１として進み、紙葉類１を透過した音波は紙葉類１内で散乱して透過音波Ａ２として分散する。紙葉類１を間にして送波器２と対向して設置された受波器３に音波ガイド５が取付けられる。送波器２の音波ガイド４の先端部と受波器３の音波ガイド５の先端部とはほぼ向き合う状態で対向しており、送波器２と受波器３との対向軸周辺部の透過音波Ａ２を受波器３で捕捉検出することができる。
【００２７】
紙葉類１が矢印Ｂ方向に移動して異物Ｑが音波ガイド４の先端部にきた場合、送波器２からの音波Ａは、反射音波Ａ１が増えて、透過音波Ａ２が減少する。音波ガイド４，５の先端部は、図２（ｂ）のように扁平状に絞られているため、小さな異物に対しても透過音波Ａ２は感度よく変化する。
【００２８】
次に、第２の実施の形態について説明する。
【００２９】
第２の実施の形態は、紙葉類１の幅方向（搬送方向Ｂと直交する方向）に、図１に示したような送波器２と受波器３との対７を複数個並設した場合で、この場合における音波ガイド４，５の先端部の配置状態を図４に示す。この例の場合、複数の送波器２と受波器３との対７を２列に交互配列したものである。
【００３０】
このように、たとえば、紙葉類１の幅が広い場合は、送波器２と受波器３との対を複数個並設して、図４に示すように音波ガイド４，５の先端部を幅方向に隙間なく配置することにより、感度よく幅広く異物検知を行なうことができる。
【００３１】
次に、第３の実施の形態について説明する。
【００３２】
第３の実施の形態は、図５に示すように、受波器３をその軸線が紙葉類１に対してほぼ直角になるよう設置したものであり、その他は図１と同じである。このように、第３の実施の形態は、受波器３と音波ガイド５の配置の変形例であり、透過音波Ａ２は紙葉類１を透過する際には散乱するため、受波器３を紙葉類１に対し概略直角方向に配置しても透過音波Ａ２を検知することができる。
【００３３】
次に、第４の実施の形態について説明する。
【００３４】
第４の実施の形態は、図６に示すように、受波器３をその軸線が紙葉類１に対してほぼ直角になるよう近接設置し、かつ、受波器３の音波ガイド５を削除したものであり、その他は図１と同じである。このように、第４の実施の形態は、受波器３を音波ガイド５をつけないで紙葉類１に接近して概略直角に設置したものであり、透過音波Ａ２が空中で減衰するのを避ける効果があり、透過音波Ａ２をより多く捕捉することができる。
【００３５】
次に、第５の実施の形態について説明する。
【００３６】
第５の実施の形態は、図７に示すように、受波器３の音波ガイド５を削除し、かつ、受波器３を紙葉類１に対して近接設置したものであり、その他は図１と同じである。このように、第５の実施の形態は、受波器３の音波ガイド５を除き送波器２の対向軸上に受波器３の軸を概略合わせて紙葉類１に近接して配置したものであり、音波の空中減衰を小さくして、透過音波Ａ２を強度の強い対向軸上で捕捉することができる。
【００３７】
次に、第６の実施の形態について説明する。
【００３８】
第６の実施の形態は、図８に示すように、送波器２をその軸線を紙葉類１に対して概略直角に設置するとともに、受波器３も送波器２と軸線を概略合わせて設置し、かつ、受波器３の音波ガイド５を削除したものであり、その他は図１と同じである。このように、第６の実施の形態は、送波器２と受波器３との対向軸を紙葉類１に対して概略直角に設置し、音波ガイド４の先端と受波器３を紙葉類１に近接させたものであり、音波ガイド４の先端を扁平状に絞ってあるため、紙葉類１からの反射波Ａ１が送波器２へ入射する量が減少する。したがって、紙葉類１の揺動による干渉波が生じにくく、異物の検知ができる。
【００３９】
次に、第７の実施の形態について説明する。
【００４０】
第７の実施の形態は、送波器２における音波ガイド４の別の構成例を示す。すなわち、図９に示すように、ブロック状の金属あるいはプラスチックで構成される音波ガイドブロック１０は、送波器２を固定するとともに音波ガイド４としての形状空間４ａを有している。また、金属あるいはプラスチック製の支持ブロック１１は、受波器３を固定支持している。このように、第７の実施の形態は、音波ガイドそのものを送波器２の支持ブロックとしたもので、作用は図８の場合と同様である。
【００４１】
次に、第８の実施の形態について説明する。
【００４２】
第８の実施の形態は、送波器２における音波ガイド４の更に別の構成例を示す。すなわち、図１０に示すように、ブロック状の金属あるいはプラスチックで構成される音波ガイドブロック１２は、送波器２を斜めに固定するとともに音波ガイド４としての形状空間４ａを有し、さらに、送波器２の支持台を兼ねている。また、金属あるいはプラスチック製の支持ブロック１３は、受波器３を固定支持している。このように、第８の実施の形態は、音波ガイドそのものを送波器２の支持ブロックとするとともに、送波器２の支持台を兼ねるもので、作用は図６の場合と同様である。
【００４３】
次に、第９の実施の形態について説明する。
【００４４】
図１１は、第９の実施の形態に係る紙葉類の異物検知装置の構成を概略的に示している。図１１において、送波器２００は、紙葉類１の幅方向（搬送方向と直交方向）の全面に対し超音波を照射できる超音波出力機能および寸法を有している。音波ガイド４０は、前記音波ガイド４と同様に紙葉類１側の断面形状が扁平状に形成されていて、送波器２００から発生する音波を扁平状に絞って紙葉類１上に照射する。
【００４５】
複数（本例では５個）の受波器３０１〜３０５は、紙葉類１を透過した音波を受けるものであり、音波ガイド４０と対向して一列に配設されている。複数（本例では５個）の音波ガイド５１〜５５は、紙葉類１を透過した音波を紙葉類１の幅方向に分割して受波器３０１〜３０５にそれぞれ導くものであり、受波器３０１〜３０５と対向して一列に配設されている。なお、音波ガイド５１〜５５は、前記音波ガイド５と同様な形状に構成されている。
【００４６】
このような構成により、紙葉類１の幅方向全面にわたり異物検知が可能となる。また、多数の音波ガイドを設置して紙葉類１の幅方向の分割を細かくし、分割数分の受波器を設置すれば、より小さな異物の検知が可能となる。さらに、送波器を１個にすることにより、受波器側においては、隣接する受波器間の音波による干渉がなく、近接して受波器およびその音波ガイドを設置することができる。
【００４７】
【発明の効果】
以上詳述したように本発明によれば、搬送される紙葉類に非接触で異物を検知でき、異物の検知限界を向上させるとともに、紙葉類の幅方向に分布する異物の検知をも可能とし、紙葉類の厚み方向の揺動による影響を受けることなく、安定して異物検知できる紙葉類の異物検知装置を提供できる。
【図面の簡単な説明】
【図１】第１の実施の形態に係る紙葉類の異物検知装置の構成を概略的に示す側面図。
【図２】音波ガイドの形状を説明する図。
【図３】紙葉類の異物検知装置の電気回路の構成を概略的に示すブロック図。
【図４】第２の実施の形態に係る紙葉類の異物検知装置における音波ガイドの配置状態を示す平面図。
【図５】第３の実施の形態に係る紙葉類の異物検知装置の構成を概略的に示す側面図。
【図６】第４の実施の形態に係る紙葉類の異物検知装置の構成を概略的に示す側面図。
【図７】第５の実施の形態に係る紙葉類の異物検知装置の構成を概略的に示す側面図。
【図８】第６の実施の形態に係る紙葉類の異物検知装置の構成を概略的に示す側面図。
【図９】第７の実施の形態に係る紙葉類の異物検知装置の構成を概略的に示す側面図。
【図１０】第８の実施の形態に係る紙葉類の異物検知装置の構成を概略的に示す側面図。
【図１１】第９の実施の形態に係る紙葉類の異物検知装置の構成を概略的に示す正面図。
【符号の説明】
１……紙葉類
２，２００……送波器
３，３０１〜３０５……受波器
４，５，４０，５１〜５５……音波ガイド
４ａ……形状空間（音波ガイド）
１０，１２……音波ガイドブロック
１１，１３……支持ブロック
２１……発振回路
２２……パワーアンプ
２３……アンプ
２４……バンドパスフィルタ
２５……整流回路
２６……比較回路
２７……比較基準設定回路[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a foreign matter detection device for a paper sheet that detects foreign matter such as a tape or a piece of paper adhering to a conveyed paper sheet.
[0002]
[Prior art]
Conventionally, for example, when detecting foreign matter on a paper sheet that is nipped and conveyed by a belt, a fixed roller with a fixed shaft and a movable roller having a support structure that can move up and down are opposed to each other and arranged as a pair in the conveyance path. The displacement amount of the movable roller when a paper sheet passes between both rollers is detected as the thickness, and a partial change in thickness is regarded as a foreign matter.
[0003]
In addition, in order to detect foreign matter in the width direction of a paper sheet, a plurality of roller pairs are arranged in a direction perpendicular to the transport direction to detect the thickness distribution, and an abnormal thickness portion is detected from the thickness change in the width direction. Is detected as a foreign object.
[0004]
Furthermore, a transmitter that generates a sound wave such as an ultrasonic wave and a receiver that receives the sound wave are arranged across the paper path, and the amount of the sound wave that passes through the paper sheet is detected by the wave receiver. However, the case where the amount of transmitted sound waves is smaller than the amount of transmitted sound wave according to the thickness of the paper sheet is detected as a foreign object, or the overlap of a plurality of paper sheets is detected.
[0005]
[Problems to be solved by the invention]
However, in the method of detecting the thickness of the paper sheet by the displacement of the movable roller, since the movable roller has a certain weight, it seems that the leading edge of the traveling paper sheet, the trailing edge is pulled out, or the tape is stuck. The follow-up to a sudden change is poor and the detection speed is limited.
[0006]
Also, when detecting the thickness distribution in the width direction of a paper sheet by arranging a plurality of roller pairs, the roller pair cannot be installed in close contact due to a roller support member or the like, and the width direction of the paper sheet It is difficult to increase the resolution.
[0007]
Furthermore, if the paper sheet is swung in the thickness direction during traveling, the rocking movement is measured as the displacement amount of the movable roller. Further, from the viewpoint of manufacturing, the processing accuracy of the roller and the roller support member is increased, and the measurement accuracy is ensured by suppressing the backlash when the roller is rotated.
[0008]
On the other hand, in a method using a sound wave such as an ultrasonic wave, the sound wave output from the transmitter spreads in the traveling direction, so the sound wave amount per unit area becomes small. For this reason, the output signal of the receiver is also reduced, the S / N is lowered, and the foreign matter detection limit cannot be raised.
[0009]
If the transmitter and the receiver are installed close to each other in order to reduce the spread of the sound wave, the sound wave is irradiated at right angles to the paper sheet. When a sound wave is applied at right angles to the paper sheet, the reflected sound wave from the paper sheet and the irradiation sound wave from the transmitter interfere with each other, and when the paper sheet is oscillated and conveyed, Therefore, the intensity of the interference wave is increased, and the intensity of the sound wave reaching the surface of the paper sheet is also increased, so that a stable transmitted sound wave cannot be obtained.
[0010]
In order to avoid such interference, for example, in the ultrasonic two-sheet detection method disclosed in Japanese Patent Laid-Open No. 6-72591, as a means for detecting whether the thickness of a sheet is one or two, By irradiating the sound wave obliquely, the reflected sound wave from the paper sheet is prevented from entering the transmitter, but by irradiating the sound wave obliquely, the sound wave between the transmitter and the receiver Since the distance becomes longer, the spread of the sound wave is inevitable, and the sound wave energy per unit area becomes smaller. Therefore, when this method is applied to foreign object detection, the detection limit of foreign objects is lowered, and it is difficult to detect smaller foreign objects.
[0011]
Therefore, the present invention can detect foreign matter in a non-contact manner with the paper sheet being conveyed, improves the detection limit of the foreign material, and also enables detection of foreign matter distributed in the width direction of the paper sheet. It is an object of the present invention to provide a paper sheet foreign matter detection device that can stably detect foreign matter without being affected by fluctuations in the thickness direction of the paper.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, a sound wave transmitter and a wave receiver are arranged so as to sandwich a sheet to be conveyed, and the wave transmitter and wave receiver, or the wave transmitter This sonic guide has a flat cross-sectional shape at the end facing the paper sheet, and the long diameter part of the end is the width direction of the paper sheet (conveying direction). perpendicular direction) and all SANYO be installed in parallel, further wave transmitter is disposed so as to irradiate sound waves from an oblique direction with respect to one surface of the paper sheet, the wave receiver is a wave transmitter It is provided in a direction orthogonal to the other surface of the paper sheet so as not to face directly.
[0013]
The sound wave output from the transmitter is converged along the sound wave guide, and is irradiated onto the surface of the paper sheet as a flat sound wave bundle. A part of the sound wave bundle irradiated on the paper sheet is reflected on the surface of the paper sheet, and a part of the sound wave is transmitted through the paper sheet. As described above, the sound wave bundle irradiated on the paper sheet is narrowed flat at the tip of the sound wave guide, so that the amount of the reflected sound wave from the surface of the paper sheet reversely enters the transmitter is reduced. The interference caused by the swinging of the paper sheets is reduced.
[0014]
The sound wave transmitted through the paper sheet is diffusely reflected by the fiber of the paper sheet, and therefore has a spread centering on the traveling line of the sound wave bundle. Therefore, the intensity of the transmitted sound wave can be known by capturing the scattered sound wave transmitted through the paper sheet with a wave receiver.
[0015]
When receiving a transmitted sound wave in a receiver, install a sound guide in the receiver as in the case of a transmitter, and install it so that the center line is roughly aligned facing the tip of the sound guide of the transmitter. Since a transmitted sound wave of a limited area is captured, a change in the transmitted sound wave due to a foreign matter on the paper sheet can be captured with high sensitivity.
[0016]
Alternatively, the receiver may be installed closer to the paper sheet without providing a sound wave guide, and the scattered sound wave may be detected by reducing the attenuation of the transmitted sound wave in the air. In this case, the sound wave may be installed near the paper sheet at right angles to the paper sheet.
[0017]
In the foreign matter detection device for a paper sheet according to the present invention configured as described above, since the sound wave from the transmitter is converged by the sound wave guide and applied to the paper sheet, the length of the end side of the tip flat portion of the sound wave guide is long. It is possible to detect the attenuation of sound waves with high sensitivity even for smaller foreign objects. In addition, since the sound waves are converged by the sound wave guide, when a plurality of transmitters are installed side by side, the interference of sound waves from adjacent transmitters is small and can be brought close to each other. Therefore, when a plurality of pairs of transmitters and receivers are installed in the width direction of the paper sheet to detect foreign matter over the entire width, the entire apparatus can be reduced in size.
[0018]
In this way, a non-contact, high-sensitivity, small-sized paper sheet foreign matter detection apparatus can be realized.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0020]
First, the first embodiment will be described.
[0021]
FIG. 1 schematically shows the configuration of a foreign matter detection apparatus for paper sheets according to a first embodiment. In FIG. 1, reference numeral 1 denotes paper sheets, which are sandwiched by a conveyance belt (not shown) and conveyed in the direction of the arrow B shown in the figure. Q is a foreign matter such as a tape or a piece of paper attached to the paper sheet 1. 2 is a transmitter for irradiating the paper sheet 1 with ultrasonic waves, 3 is a receiver for receiving the sound wave transmitted through the paper sheet 1, and these are relative to each other with the conveyed paper sheet 1 in between. It is arranged in the direction. In this case, the transmitter 2 and the receiver 3 are installed facing each other so as to irradiate the surface of the paper sheet 1 to be conveyed with sound waves obliquely and receive the transmitted sound waves. A sound wave guide 4 guides the sound wave emitted from the transmitter 2, and a sound wave guide 5 guides the sound wave transmitted through the paper sheet 1 to the wave receiver 3. Here, it is assumed that the sound wave irradiated from the transmitter 2 is A, the sound wave reflected on the surface of the paper sheet 1 is A1, and the sound wave transmitted through the paper sheet 1 and scattered is A2.
[0022]
The sonic guides 4 and 5 have, for example, a cross-sectional shape as shown in FIG. That is, the cross-sectional shape along the X1-X1 line on the transmitter 2 side of the sonic guide 4 is substantially circular as shown in FIG. 2A, and X2-X2 on the paper sheet 1 side (tip portion) of the sonic guide 4. The cross-sectional shape along the line is flat as shown in FIG. 2 (b), and the long diameter portion of the flat portion is parallel to the width direction of the paper sheet 1 (perpendicular to the conveying direction B). A sonic guide 4 is installed. The sound wave guide 5 on the receiver 3 side has the same structure and arrangement.
[0023]
FIG. 3 shows an electric circuit of the foreign object detection apparatus configured as described above. An oscillation circuit 21 generates an AC voltage having a band of 20 kHz to 50 kHz, for example. A power amplifier 22 amplifies the AC voltage from the oscillation circuit 21 and drives the transmitter 2 with the amplified output. An amplifier 23 amplifies the output signal of the receiver 3. Reference numeral 24 denotes a bandpass filter (BPF) having the frequency of the oscillation circuit 21 as a center frequency, and removes a noise component from the output signal of the amplifier 23. A rectifier circuit 25 converts the output signal of the bandpass filter 24 into a DC signal. A comparison circuit 26 compares the output signal of the rectification circuit 25 with the comparison reference value set by the comparison reference setting circuit 27, and outputs a foreign substance presence / absence signal.
[0024]
In such a configuration, the AC voltage output from the oscillation circuit 21 is amplified by the power amplifier 22, and the transmitter 2 is driven by the amplified output. The sound wave transmitted through the paper sheet 1 is converted into an electric signal by the receiver 3 to become a transmitted sound wave signal, amplified by the amplifier 23 and sent to the bandpass filter 24, where the noise component is removed, It is converted into a DC signal by the rectifier circuit 25 and sent to the comparison circuit 26. The comparison circuit 26 compares the output signal of the rectifier circuit 25 with the comparison reference value set by the comparison reference setting circuit 27. When the output signal of the rectification circuit 25 becomes a voltage value lower than the comparison reference value, the foreign matter is detected. A foreign matter presence signal is output as being present.
[0025]
Next, the operation will be described.
[0026]
As shown in FIG. 1, when the wave transmitter 2 is installed so that the wave transmission axis of the sound wave is inclined with respect to the paper sheet 1, and the sound wave guide 4 is attached to the wave transmitter 2 and the sound wave A is irradiated, A is reflected on the surface of the paper sheet 1 and proceeds as a reflected sound wave A1, and the sound wave transmitted through the paper sheet 1 is scattered in the paper sheet 1 and dispersed as a transmitted sound wave A2. A sound wave guide 5 is attached to a wave receiver 3 installed opposite to the wave transmitter 2 with the paper sheet 1 in between. The tip of the sound wave guide 4 of the transmitter 2 and the tip of the sound wave guide 5 of the receiver 3 are opposed to each other so as to face each other. The transmitted sound wave A2 can be captured and detected by the receiver 3.
[0027]
When the paper sheet 1 moves in the direction of the arrow B and the foreign matter Q comes to the tip of the sound wave guide 4, the sound wave A from the transmitter 2 increases the reflected sound wave A1 and decreases the transmitted sound wave A2. Since the tip portions of the sound wave guides 4 and 5 are narrowed as shown in FIG. 2B, the transmitted sound wave A2 changes with high sensitivity even for a small foreign object.
[0028]
Next, a second embodiment will be described.
[0029]
In the second embodiment, a plurality of pairs 7 of the transmitter 2 and the receiver 3 as shown in FIG. 1 are arranged in parallel in the width direction of the paper sheet 1 (direction orthogonal to the conveyance direction B). FIG. 4 shows an arrangement state of the tip portions of the sound wave guides 4 and 5 in this case. In the case of this example, pairs 7 of a plurality of transmitters 2 and receivers 3 are alternately arranged in two rows.
[0030]
Thus, for example, when the width of the paper sheet 1 is wide, a plurality of pairs of the transmitter 2 and the receiver 3 are arranged in parallel, and as shown in FIG. By arranging the portions in the width direction without any gaps, it is possible to detect a wide range of foreign matters with high sensitivity.
[0031]
Next, a third embodiment will be described.
[0032]
In the third embodiment, as shown in FIG. 5, the receiver 3 is installed so that the axis thereof is substantially perpendicular to the paper sheet 1, and the rest is the same as FIG. As described above, the third embodiment is a modified example of the arrangement of the wave receiver 3 and the sound wave guide 5, and the transmitted sound wave A 2 is scattered when passing through the paper sheet 1. The transmitted sound wave A2 can be detected even if the sound wave is arranged in a direction substantially perpendicular to the paper sheet 1.
[0033]
Next, a fourth embodiment will be described.
[0034]
In the fourth embodiment, as shown in FIG. 6, the receiver 3 is installed close to each other so that the axis thereof is substantially perpendicular to the paper sheet 1, and the sound wave guide 5 of the receiver 3 is provided. The other parts are the same as in FIG. As described above, in the fourth embodiment, the receiver 3 is installed at a substantially right angle close to the paper sheet 1 without attaching the sound wave guide 5, and the transmitted sound wave A2 is attenuated in the air. Can be captured and more transmitted sound waves A2 can be captured.
[0035]
Next, a fifth embodiment will be described.
[0036]
In the fifth embodiment, as shown in FIG. 7, the sound wave guide 5 of the wave receiver 3 is deleted, and the wave receiver 3 is installed close to the paper sheet 1, and the others are The same as FIG. As described above, in the fifth embodiment, the axis of the wave receiver 3 is roughly aligned on the opposite axis of the wave transmitter 2 except for the sound wave guide 5 of the wave receiver 3 and is arranged close to the paper sheet 1. Therefore, the transmitted sound wave A <b> 2 can be captured on the opposed axis having a high intensity by reducing the attenuation of the sound wave in the air.
[0037]
Next, a sixth embodiment will be described.
[0038]
In the sixth embodiment, as shown in FIG. 8, the transmitter 2 is installed so that its axis is substantially perpendicular to the paper sheet 1, and the receiver 3 also has an axis similar to that of the transmitter 2. In addition, the sound wave guide 5 of the receiver 3 is omitted, and the rest is the same as FIG. As described above, in the sixth embodiment, the opposed axes of the transmitter 2 and the receiver 3 are installed at a substantially right angle with respect to the paper sheet 1, and the tip of the sound wave guide 4 and the receiver 3 are connected. Since the tip of the sound wave guide 4 is narrowed in a flat shape, the amount of the reflected wave A1 from the paper sheet 1 entering the transmitter 2 is reduced. Therefore, an interference wave due to the swing of the paper sheet 1 is hardly generated, and foreign matter can be detected.
[0039]
Next, a seventh embodiment will be described.
[0040]
The seventh embodiment shows another configuration example of the sound wave guide 4 in the transmitter 2. That is, as shown in FIG. 9, the sonic wave guide block 10 made of block-shaped metal or plastic has a shape space 4 a as the sonic wave guide 4 while fixing the transmitter 2. A support block 11 made of metal or plastic fixes and supports the wave receiver 3. Thus, in the seventh embodiment, the sound wave guide itself is used as the support block of the transmitter 2, and the operation is the same as in the case of FIG.
[0041]
Next, an eighth embodiment will be described.
[0042]
The eighth embodiment shows still another configuration example of the sound wave guide 4 in the transmitter 2. That is, as shown in FIG. 10, the sonic wave guide block 12 made of block-shaped metal or plastic has a shape space 4a as the sonic wave guide 4 while fixing the transmitter 2 diagonally, and further, Also serves as a support for the waver 2. A support block 13 made of metal or plastic fixes and supports the wave receiver 3. Thus, in the eighth embodiment, the sound wave guide itself is used as a support block for the transmitter 2 and also serves as a support for the transmitter 2, and the operation is the same as in the case of FIG.
[0043]
Next, a ninth embodiment will be described.
[0044]
FIG. 11 schematically shows the configuration of a foreign matter detection apparatus for paper sheets according to a ninth embodiment. In FIG. 11, the wave transmitter 200 has an ultrasonic output function and dimensions capable of irradiating ultrasonic waves on the entire surface of the paper sheet 1 in the width direction (direction orthogonal to the transport direction). The sonic guide 40 is formed in a flat cross-sectional shape on the side of the paper sheet 1 like the sonic wave guide 4, and the sound wave generated from the transmitter 200 is squeezed into the flat shape and irradiated onto the paper sheet 1. To do.
[0045]
A plurality (five in this example) of the receivers 301 to 305 receive the sound wave transmitted through the paper sheet 1 and are arranged in a row facing the sound wave guide 40. The plurality of (5 in this example) sound wave guides 51 to 55 divide the sound wave transmitted through the paper sheet 1 in the width direction of the paper sheet 1 and guide it to the wave receivers 301 to 305, respectively. It is arranged in a row so as to face the wave devices 301 to 305. The sound wave guides 51 to 55 are configured in the same shape as the sound wave guide 5.
[0046]
With this configuration, foreign matter can be detected over the entire width of the paper sheet 1. Further, if a large number of sound wave guides are installed to finely divide the paper sheet 1 in the width direction, and a number of receivers are installed, smaller foreign objects can be detected. Furthermore, by using one transmitter, there is no interference due to sound waves between adjacent receivers on the receiver side, and the receiver and its sound guide can be installed close to each other.
[0047]
【The invention's effect】
As described above in detail, according to the present invention, foreign matter can be detected in a non-contact manner on the conveyed paper sheet, the detection limit of the foreign matter is improved, and foreign matter distributed in the width direction of the paper sheet is also detected. It is possible to provide a foreign matter detection device for paper sheets that can be stably detected without being affected by the swinging of the thickness direction of the paper sheets.
[Brief description of the drawings]
FIG. 1 is a side view schematically showing a configuration of a paper sheet foreign matter detection apparatus according to a first embodiment.
FIG. 2 is a view for explaining the shape of a sound wave guide.
FIG. 3 is a block diagram schematically showing a configuration of an electric circuit of a foreign matter detection apparatus for paper sheets.
FIG. 4 is a plan view showing an arrangement state of sound wave guides in the foreign matter detection apparatus for paper sheets according to the second embodiment.
FIG. 5 is a side view schematically showing a configuration of a foreign matter detection apparatus for paper sheets according to a third embodiment.
FIG. 6 is a side view schematically showing a configuration of a paper sheet foreign matter detection apparatus according to a fourth embodiment.
FIG. 7 is a side view schematically showing the configuration of a paper sheet foreign matter detection apparatus according to a fifth embodiment.
FIG. 8 is a side view schematically showing the configuration of a paper sheet foreign matter detection apparatus according to a sixth embodiment.
FIG. 9 is a side view schematically showing a configuration of a paper sheet foreign matter detection apparatus according to a seventh embodiment.
FIG. 10 is a side view schematically showing a configuration of a paper sheet foreign matter detection apparatus according to an eighth embodiment.
FIG. 11 is a front view schematically showing a configuration of a paper sheet foreign object detection device according to a ninth embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Paper sheets 2,200 ... Transmitter 3, 301-305 ... Receiver 4, 5, 40, 51-55 ... Sonic guide 4a ... Shape space (Sonic guide)
10, 12... Sonic wave guide blocks 11 and 13... Support block 21... Oscillation circuit 22... Power amplifier 23. Setting circuit

Claims

A wave transmitter that emits sound waves from an oblique direction to one side of the conveyed paper sheet;
This guides the sound wave emitted from the transmitter to the paper sheet, and the cross-sectional shape of the end facing the paper sheet is flat in the direction perpendicular to the transport direction of the paper sheet. A sonic guide,
A wave receiver provided in a direction orthogonal to the other surface of the paper sheet, receiving a sound wave irradiated from the transmitter and transmitted through the paper sheet;
A foreign matter detection device for paper sheets, comprising:

A wave transmitter that emits sound waves from an oblique direction to one side of the conveyed paper sheet;
This guides the sound wave emitted from the transmitter to the paper sheet, and the cross-sectional shape of the end facing the paper sheet is flat in the direction perpendicular to the transport direction of the paper sheet. A first sonic guide,
A wave receiver provided in a direction orthogonal to the other surface of the paper sheet, receiving a sound wave irradiated from the transmitter and transmitted through the paper sheet;
The sound wave transmitted through the paper sheet is guided to the receiver, and the cross-sectional shape of the end portion facing the paper sheet is flat in a direction perpendicular to the conveyance direction of the paper sheet. Two sonic guides,
A foreign matter detection device for paper sheets, comprising:

A plurality of transmitters arranged in a direction orthogonal to the transport direction of the transported paper sheets and irradiating sound waves from an oblique direction on one surface of the transported paper sheets;
Each of the sound waves emitted from the plurality of transmitters to the paper sheet is guided, and the cross-sectional shape of the end facing the paper sheet is perpendicular to the conveying direction of the paper sheet. A plurality of flat acoustic guides,
In a direction orthogonal to the other surface of the transported paper sheet, it is arranged in a direction orthogonal to the transport direction of the paper sheet, irradiated from the plurality of transmitters, and transmitted through the paper sheet A plurality of receivers for receiving each sound wave;
A foreign matter detection device for paper sheets, comprising:

A plurality of transmitters arranged in a direction orthogonal to the transport direction of the transported paper sheets and irradiating sound waves from an oblique direction on one surface of the transported paper sheets;
Each of the sound waves emitted from the plurality of transmitters to the paper sheet is guided, and the cross-sectional shape of the end facing the paper sheet is perpendicular to the conveying direction of the paper sheet. A plurality of first sonic guides that are flat;
In a direction orthogonal to the other surface of the transported paper sheet, it is arranged in a direction orthogonal to the transport direction of the paper sheet, irradiated from the plurality of transmitters, and transmitted through the paper sheet A plurality of receivers for receiving each sound wave;
Each sound wave transmitted through the paper sheet is guided to the plurality of receivers, and a cross-sectional shape of an end portion facing the paper sheet is flat in a direction orthogonal to the conveyance direction of the paper sheet. A plurality of second sonic guides,
A foreign matter detection device for paper sheets, comprising:

A single transmitter for irradiating sound waves from one direction to one side of the conveyed paper sheet;
Guides the sound wave emitted from the single transmitter to the paper sheet, and the cross-sectional shape of the end facing the paper sheet is flat in the direction orthogonal to the transport direction of the paper sheet. A sonic wave guide,
Arranged in a direction orthogonal to the other surface of the paper sheet to be transported , orthogonal to the transport direction of the paper sheet, irradiated from the single transmitter, and transmitted through the paper sheet A plurality of receivers that receive the received sound waves,
A foreign matter detection device for paper sheets, comprising:

A single transmitter for irradiating sound waves from one direction to one side of the conveyed paper sheet;
Guides the sound wave emitted from the single transmitter to the paper sheet, and the cross-sectional shape of the end facing the paper sheet is flat in the direction orthogonal to the transport direction of the paper sheet. A first sonic guide in a shape;
Arranged in a direction orthogonal to the other surface of the paper sheet to be transported , orthogonal to the transport direction of the paper sheet, irradiated from the single transmitter, and transmitted through the paper sheet A plurality of receivers that receive the received sound waves,
Each of the sound waves transmitted through the paper sheet is guided to the plurality of receivers, and a cross-sectional shape of an end portion facing the paper sheet is flat in a direction perpendicular to the conveyance direction of the paper sheet. A plurality of second sonic guides,
A foreign matter detection device for paper sheets, comprising:

Wherein the single wave transmitter is claim 5 or claim and then irradiating sound waves from an oblique direction with respect to the width the entire surface of the conveying direction and the perpendicular direction of the one surface of the paper sheet to be the transport 6. The foreign matter detection apparatus for paper sheets according to 6 .