JPH0752083B2 - Paper thickness detector - Google Patents
Paper thickness detectorInfo
- Publication number
- JPH0752083B2 JPH0752083B2 JP2035571A JP3557190A JPH0752083B2 JP H0752083 B2 JPH0752083 B2 JP H0752083B2 JP 2035571 A JP2035571 A JP 2035571A JP 3557190 A JP3557190 A JP 3557190A JP H0752083 B2 JPH0752083 B2 JP H0752083B2
- Authority
- JP
- Japan
- Prior art keywords
- paper
- circuit
- series
- detection
- tuning
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、静電センサ装置を用いた紙厚検出装置に関す
るものである。The present invention relates to a paper thickness detection device using an electrostatic sensor device.
複写機や紙幣識別装置等では、紙が２枚送りされると、
様々な支障が生じる。このことから、これらの装置には
紙厚検出装置が設けられ、紙が２枚送りされたときに
は、これを検出して装置を停止させたり、あるいは、そ
の２枚送りされた紙を排出する等の手段が設けられてい
る。In a copying machine or a bill validator, when two sheets of paper are fed,
Various troubles occur. Therefore, these devices are provided with a paper thickness detecting device, and when two sheets of paper are fed, it is detected and the device is stopped, or the two fed sheets are discharged. Means are provided.
第７図には前記複写機や紙幣識別装置等に使用されてい
る一般的な紙厚検出装置が示されている。この装置は、
紙１の走行通路領域２上にポテンショメータ３を配置す
ることにより構成されている。このポテンショメータ３
は回転軸3aに接触針3bを装着し、この接触針3bの先端を
常時紙１側に付勢して紙１に接触させるようにしてお
き、紙圧の変化に伴って接触針3bを矢印方向に回転さ
せ、この接触針3bの回転角を電圧変化に変換して取り出
すものである。FIG. 7 shows a general paper thickness detecting device used in the copying machine and the bill validator. This device
It is configured by arranging a potentiometer 3 on the traveling passage area 2 of the paper 1. This potentiometer 3
Attaches the contact needle 3b to the rotating shaft 3a, and always keeps the tip of the contact needle 3b urged toward the paper 1 so as to contact the paper 1. The rotation angle of the contact needle 3b is converted into a voltage change and taken out.
しかしながら、従来のポテンショメータを用いた装置で
は、接触針3bを紙１に接触した状態で紙厚を検出してい
るため、紙の走行速度が速くなると、接触針3bの動きが
これに追従できず、紙の走行速度が制限されるという問
題がある。However, in the device using the conventional potentiometer, the thickness of the paper is detected while the contact needle 3b is in contact with the paper 1. Therefore, when the traveling speed of the paper increases, the movement of the contact needle 3b cannot follow this. However, there is a problem that the traveling speed of paper is limited.
また、複写用紙や紙幣等の薄紙の変化を接触針3bの回転
角により検出するものであるため、２枚送り時の紙厚の
変化等に対する接触針3bの回転角の変化が極めて小さ
く、紙圧の変化を正確に検出するためにはポテンショメ
ータ３を超高精度なものにしなければならず、装置構成
も複雑になり、装置コストも高価になるという問題があ
る。Further, since the change in the thin paper such as copy paper or bills is detected by the rotation angle of the contact needle 3b, the change in the rotation angle of the contact needle 3b with respect to the change in the paper thickness when feeding two sheets is extremely small. In order to accurately detect the change in pressure, the potentiometer 3 must be made extremely highly accurate, which complicates the device configuration and raises the cost of the device.
本発明は上記従来の課題を解決するためになされたもの
であり、その目的は、紙の走行速度を高速にしても、紙
厚の変化を高精度のもとに検出することができる装置構
成の簡易な厚紙検出装置を提供することにある。The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is an apparatus configuration capable of detecting a change in paper thickness with high accuracy even when the traveling speed of paper is high. To provide a simple cardboard detection device.
本発明は上記目的を達成するために、つぎの様に構成さ
れている。すなわち、本発明の紙厚検出装置は、紙の走
行通路領域に前後させ、かつ、紙に対して非接触状態で
設けられる第１および第２の２系列の検出電極と；固定
の発振周波数を発振出力する１個の発振回路と；前記発
振回路とは別個独立の共振器を備え、前記第１の系列の
検出電極によって検出される静電容量の変化を受けて前
記発振回路の固定の発振周波数に対する共振周波数の同
調点を変化させ、この同調点の変化に対応した検出信号
を出力する第１の系列の同調回路と；前記発振回路およ
び第１の系列の同調回路とは別個独立の共振器を備え、
前記第２の系列の検出電極によって検出される静電容量
の変化を受けて前記発振回路の固定の発振周波数に対す
る共振周波数の同調点を変化させ、この同調点の変化に
対応した検出信号を出力する第２の系列の同調回路
と。；前記第１の系列の同調回路からの検出信号と第２
の系列の同調回路からの検出信号との差の信号を出力す
る出力回路と；を有することを特徴として構成されてい
る。The present invention is configured as follows to achieve the above object. That is, the paper thickness detection device of the present invention includes first and second two series of detection electrodes which are provided in front of and behind the paper passage area and are in non-contact with the paper; One oscillation circuit that oscillates and outputs; a resonator that is independent of the oscillation circuit, and has a fixed oscillation of the oscillation circuit in response to a change in capacitance detected by the detection electrode of the first series. A tuning circuit of a first series that changes a tuning point of a resonance frequency with respect to a frequency and outputs a detection signal corresponding to the change of the tuning point; and a resonance independent of the oscillation circuit and the tuning circuit of the first series. Equipped with a vessel,
The tuning point of the resonance frequency with respect to the fixed oscillation frequency of the oscillation circuit is changed in response to the change of the capacitance detected by the detection electrode of the second series, and the detection signal corresponding to the change of the tuning point is output. And a second series of tuning circuits. A detection signal from the tuning circuit of the first series and a second signal
And an output circuit that outputs a signal of a difference from the detection signal from the tuning circuit of the series.
本発明において、例えば、走行通路領域の上流側に第１
の系列の検出電極が、それよりも下流側に第２の系列の
検出電極が配置されているとき、走行通路領域に沿って
紙が第１の系列の検出電極の位置に来ると、第１の系列
の検出電極の検出領域の静電容量の変化として、検出さ
れ、その検出結果は第１の系列の同調回路へ加えられ
る。同様に、紙が第２の系列の検出電極に至ると、この
第２の系列の検出電極の検出領域の静電容量の変化とし
て検出され、その検出結果は第２の系列の同調回路へ加
えられる。前期第１の系列の同調回路および第２の系列
の同調回路は対応する検出電極から加えられる静電容量
の変化を受けて共振周波数を偏倚させ、発振回路の固定
の発振周波数に対する共振周波数の同調点を変化させ、
この同調点の変化に対応した紙厚の検出信号を出力回路
へ加える。出力回路は、第１の系列の同調回路側から加
えられる検出信号と第２の系列の同調回路側から加えら
れる検出信号との差を取り、その差動信号を紙厚等を演
算する所望の信号処理回路へ加えるのである。In the present invention, for example, the first
When the second series of detection electrodes are arranged on the downstream side of the first series of detection electrodes and the paper comes to the position of the first series of detection electrodes along the traveling path region, This is detected as a change in the capacitance of the detection area of the detection electrode of the first series, and the detection result is added to the tuning circuit of the first series. Similarly, when the paper reaches the detection electrode of the second series, it is detected as a change in the capacitance of the detection area of the detection electrode of the second series, and the detection result is added to the tuning circuit of the second series. To be The tuning circuit of the first series and the tuning circuit of the second series bias the resonance frequency in response to a change in the capacitance applied from the corresponding detection electrode, and tune the resonance frequency to the fixed oscillation frequency of the oscillation circuit. Change the points,
A paper thickness detection signal corresponding to the change in the tuning point is applied to the output circuit. The output circuit takes the difference between the detection signal applied from the first series tuning circuit side and the detection signal applied from the second series tuning circuit side, and calculates the paper thickness and the like of the differential signal. It is added to the signal processing circuit.
以下、本発明の一実施例を図面に基づいて説明する。な
お、本明細書で紙とは、紙幣や複写機の用紙はもちろ
ん、それ以外の紙、カード、プラスチックのフィルムや
シート等を含む広い概念で使用されている。An embodiment of the present invention will be described below with reference to the drawings. In this specification, paper is used in a broad concept including paper money, paper for copying machines, and other paper, cards, plastic films and sheets, and the like.
第１図には本発明に係る紙厚検出装置の一実施例のブロ
ック図が示されている。本実施例の装置は、一個の発振
回路６と、分配器16と、第１の系列のセンサ回路11a
と、第２の系列のセンサ回路11bと、出力回路としての
差動増幅器17と、第１の系列の電極検出器8aと、第２の
系列の電極検出部8bとからなる。第１の系列の電極検出
器8aは検出電極14aと接地電極15とかなり、第２の系列
の電極検出器8bは検出電極14bと接地電極15からなる。
接地電極15と検出電極14a,14bは紙１の走行通路領域２
を挟んで、つまり、紙１の通過間隙を介して対向配置さ
れており、検出電極14aは検出電極14bに対して上流側に
配置されている。前記第１の系列のセンサ回路11aと第
２の系列のセンサ回路11bとは同一の回路構成となって
おり、第２図には発振回路６と、分配器16と、第１の系
列のセンサ回路11aと、第１の系列の電極検出部8aとを
抜き出した具体的な回路例が示されている。FIG. 1 is a block diagram of an embodiment of the paper thickness detecting device according to the present invention. The device of this embodiment includes one oscillator circuit 6, a distributor 16, and a first series sensor circuit 11a.
A second series sensor circuit 11b, a differential amplifier 17 as an output circuit, a first series electrode detector 8a, and a second series electrode detector 8b. The first series of electrode detectors 8a comprises a detection electrode 14a and a ground electrode 15, and the second series of electrode detectors 8b comprises a detection electrode 14b and a ground electrode 15.
The ground electrode 15 and the detection electrodes 14a and 14b are used for the traveling passage area 2 of the paper 1.
, That is, they are arranged opposite to each other with a passage gap of the paper 1 interposed therebetween, and the detection electrode 14a is arranged upstream of the detection electrode 14b. The first series sensor circuit 11a and the second series sensor circuit 11b have the same circuit configuration, and in FIG. 2, the oscillation circuit 6, the distributor 16, and the first series sensor are shown. A specific circuit example in which the circuit 11a and the first series of electrode detection units 8a are extracted is shown.
前記発振回路６には1GHz〜10GHzの範囲内の固定された
一定の超高周波の発振周波数、本実施例では1GHZの発振
周波数を発振するセラミック共振器10が用いられてい
る。この発振回路６は前記高周波の発振周波数信号を発
振し、これを高インピーダンス変換回路6aを介して分配
器16に加える。分配器16はこの発振周波数信号を分配し
て第１の系列のセンサ回路11aと第２の系列のセンサ回
路11bへ加える。センサ回路11aは同調回路（第１の系列
の同調回路）7aと、検波回路4aと、AFC回路（自動利得
制御回路）9aと、増幅回路5aとからなる。同調回路7aは
セラミック共振器12によって構成され、このセラミック
共振器12の信号入力側には電極検出部8aの検出電極14a
が接続されている。なお、接地電極15はセラミック共振
器12のグランド側（接地側）にそれぞれ接続されてい
る。Fixed fixed VHF oscillation frequency in the range of 1GHz~10GHz to the oscillation circuit 6, is used a ceramic resonator 10 which oscillates the oscillation frequency of 1GH Z in this embodiment. The oscillating circuit 6 oscillates the high-frequency oscillating frequency signal and applies it to the distributor 16 via the high impedance converting circuit 6a. The distributor 16 distributes this oscillation frequency signal and adds it to the first series sensor circuit 11a and the second series sensor circuit 11b. The sensor circuit 11a includes a tuning circuit (first series tuning circuit) 7a, a detection circuit 4a, an AFC circuit (automatic gain control circuit) 9a, and an amplifier circuit 5a. The tuning circuit 7a is composed of a ceramic resonator 12, and the signal input side of the ceramic resonator 12 has a detection electrode 14a of an electrode detection unit 8a.
Are connected. The ground electrode 15 is connected to the ground side (ground side) of the ceramic resonator 12, respectively.
セラミック共振器12は第３図に示すような共振周波数特
性を有しており、このセラミック共振器12の共振周波数
f2に対して発振回路６の固定発振周波数foscはわずかに
ずらした位置に設定される。セラミック共振器12の共振
周波数f2は電極検出部8aによって検出される電極14a,15
間の静電容量の変化に応じて偏倚し、例えば、静電容量
Ｃが＋ΔＣだけ変化すると共振周波数f2はf1に偏倚す
る。発振回路６の発振周波数はfoscに固定されているか
ら、静電容量変化がないときにはセラミック共振器12か
ら固定発振周波数foscと共振周波数f2の共振周波数との
同調点A2におけるV2の出力電圧が送出されるが、静電容
量変化が＋ΔＣになったときには共振周波数f1に偏倚
し、同調点がA2からA1に変化してセラミック共振器12か
らV1の出力電圧が送出される。このように、電極14a,15
間の静電容量の変化に応じてセラミック共振器12の共振
周波数が偏倚し、これに伴い、セラミック共振器12から
静電容量変化に対応する同調点変化の出力電圧Ｖが送出
されるのである。The ceramic resonator 12 has a resonance frequency characteristic as shown in FIG.
The fixed oscillation frequency f osc of the oscillator circuit 6 is set at a position slightly shifted with respect to f 2 . The resonance frequency f 2 of the ceramic resonator 12 is the electrodes 14a, 15 detected by the electrode detection unit 8a.
The capacitance fluctuates in accordance with the change in the capacitance between them, and for example, when the capacitance C changes by + ΔC, the resonance frequency f 2 is biased to f 1 . Since the oscillation frequency of the oscillation circuit 6 is fixed to f osc , V 2 at the tuning point A 2 between the fixed oscillation frequency f osc and the resonance frequency of the resonance frequency f 2 from the ceramic resonator 12 when the capacitance does not change. , But when the capacitance change becomes + ΔC, it is biased to the resonance frequency f 1 , the tuning point changes from A 2 to A 1, and the output voltage of V 1 from the ceramic resonator 12 changes. Sent out. In this way, the electrodes 14a, 15
The resonance frequency of the ceramic resonator 12 is deviated in accordance with the change of the electrostatic capacitance between them, and accordingly, the output voltage V of the tuning point change corresponding to the electrostatic capacitance change is sent from the ceramic resonator 12. .
検波回路4aは結合コンデンサ25を介してセラミック共振
器12に接続されており、この検波回路4aはインダクタン
ス素子21と、ダイオード22と、コンデンサ23と、抵抗器
24とによって構成されており、前記セラミック共振器12
からの出力信号は結合コンデンサ25を介して検波回路4a
に加えられるようになっている。前記ダイオード22と、
コンデンサ23と、抵抗器24は検波回路4aの検波部を構成
しており、また、インダクタンス素子21とコンデンサ25
は高インピーダンス化回路として機能している。この検
波回路4aはセラミック共振器12から出力される超高周波
の出力信号（画像信号）を包絡線検波し、紙厚検出の信
号帯域の信号に変換して増幅回路5aとAFC回路9aへ加え
る。The detection circuit 4a is connected to the ceramic resonator 12 via a coupling capacitor 25. This detection circuit 4a includes an inductance element 21, a diode 22, a capacitor 23, and a resistor.
24 and the ceramic resonator 12
The output signal from the detection circuit 4a passes through the coupling capacitor 25.
To be added to. The diode 22;
The capacitor 23 and the resistor 24 form a detection unit of the detection circuit 4a, and the inductance element 21 and the capacitor 25
Functions as a high impedance circuit. The detection circuit 4a performs envelope detection of an ultra-high frequency output signal (image signal) output from the ceramic resonator 12, converts it into a signal in a signal band for paper thickness detection, and applies it to the amplification circuit 5a and the AFC circuit 9a.
増幅回路5aはトランジスタ27と抵抗器等の素子を用いて
構成され、この増幅回路5aは検波回路4aから加えられる
信号を増幅し差動増幅器に供給する。The amplifier circuit 5a is configured by using a transistor 27 and elements such as a resistor, and the amplifier circuit 5a amplifies the signal applied from the detection circuit 4a and supplies it to the differential amplifier.
AFC回路9aは、紙１のしわや破れ等の外乱によって同調
点が紙厚検出の設定利得領域からはずれるのを防止し、
紙１に破れやしわがあっても紙厚を正確に検出できるよ
うにするものである。The AFC circuit 9a prevents the tuning point from deviating from the set gain area for paper thickness detection due to disturbances such as wrinkles and tears on the paper 1.
Even if the paper 1 is torn or wrinkled, the paper thickness can be accurately detected.
本実施例は、前述したように、第１の系列のセンサ回路
11aと同一構成の第２の系列のセンサ回路11bが設けら
れ、この第２の系列のセンサ回路11bも、分配器16から
発振回路６の発振周波数信号の分配供給を受けて、前期
第１の系列のセンサ回路と同様に回路動作を行うもので
ある。As described above, this embodiment is based on the first series of sensor circuits.
A second series sensor circuit 11b having the same configuration as that of 11a is provided, and the second series sensor circuit 11b also receives the distributed supply of the oscillation frequency signal of the oscillation circuit 6 from the distributor 16 and receives the first-term The circuit operates similarly to the series sensor circuit.
本発明は以上説明したように構成されており、以下、紙
厚検出動作について説明する。The present invention is configured as described above, and the paper thickness detection operation will be described below.
検出電極14a,14bと接地電極15との間に紙１の通過がな
い状態で、第３図に示すように、セラミック共振器12の
共振周波数（同調周波数）f2に対して発振回路６の固定
発振周波数fOSCはわずかに外れた位置に設定される。こ
のとき、セラミック共振器12からV2の一定電圧が出力さ
れる。この状態で、紙１の通過経路（走行通路領域）２
から１枚の紙１（Ｎ＝１の紙,Nは紙の枚数）が電極14a,
15の間にその先端が入ると、検出電極14aと接地電極15
間の静電容量が変化する。この静電容量の微小変化によ
り、発振回路６の発振周波数fOSCに対して第１の系列の
同調回路7a側のセラミック共振器12の共振周波数がf2か
らf1に偏倚し、固定発振周波数fOSCと同調回路7a側の共
振周波数との同調点がA2からA1に移行し、セラミック共
振器12からV1の電圧が出力される。同様に、通過経路２
を通る紙１が２枚重なって電極14a,15間に入り込むと、
電極14a,15間の静電容量がさらに変化し、セラミック共
振器12の共振周波はf0に偏倚し、同調点がA1からA0に移
行し、セラミック共振器12からV0の電圧が出力される。As shown in FIG. 3, in the state where the paper 1 does not pass between the detection electrodes 14a and 14b and the ground electrode 15, the oscillation frequency of the oscillation circuit 6 is different from the resonance frequency (tuning frequency) f 2 of the ceramic resonator 12. The fixed oscillation frequency f OSC is set to a position slightly off. At this time, the ceramic resonator 12 outputs a constant voltage of V 2 . In this state, the passage path (running passage area) 2 of the paper 1
From 1 sheet of paper 1 (N = 1 sheet of paper, N is the number of sheets of paper) to electrode 14a,
When the tip enters between 15, the detection electrode 14a and the ground electrode 15
The capacitance between them changes. Due to this small change in capacitance, the resonance frequency of the ceramic resonator 12 on the tuning circuit 7a side of the first series is deviated from f 2 to f 1 with respect to the oscillation frequency f OSC of the oscillation circuit 6, and the fixed oscillation frequency. The tuning point between f OSC and the resonance frequency on the tuning circuit 7a side shifts from A 2 to A 1 , and the ceramic resonator 12 outputs the voltage of V 1 . Similarly, passage route 2
When two sheets of paper 1 passing through are overlapped between the electrodes 14a and 15,
The capacitance between the electrodes 14a and 15 is further changed, the resonance frequency of the ceramic resonator 12 is biased to f 0 , the tuning point shifts from A 1 to A 0, and the voltage of V 0 from the ceramic resonator 12 changes. Is output.
同様に、紙１が検出電極14bと接地電極15との間を通過
するときには、この紙１の通過に伴う静電容量の変化が
第２の系列の電極検出部8bで検出され、その検出結果が
第２の系列の同調回路7b側のセラミック共振器12へ加え
られ、同共振器12から紙厚に対応する出力電圧が出力さ
れる。第１の系列および第２の系列のセラミック共振器
12はこれら紙厚に対応する出力電圧の変化からAM変調波
を作り出し、これを検出信号として対応する検波回路4
a,4bに加える。すなわち、第１の系列のセラミック共振
器12は発振周波数fOSCと検出電極14aで検出される紙厚
の変化に対応する共振周波数の変化成分Δｆとの掛け算
を行い、AM変調波を得る。同様に、第２の系列のセラミ
ック共振器12は発振周波数fOSCと検出電極14bで検出さ
れる紙厚の変化に対応する共振周波数の変化成分Δｆと
の掛け算を行い、AM変調波を得る。本実施例では、発振
周波数fOSCは1GHZであるので、変調波としての検出信号
は1GHZを中心とし、紙厚の変化に対応した帯域福を持っ
た超高周波の信号になり、この超高周波の信号が各系列
のセラミック共振器12から対応する検波回路4a,4bに加
えられるものである。Similarly, when the paper 1 passes between the detection electrode 14b and the ground electrode 15, the change in the capacitance due to the passage of the paper 1 is detected by the electrode detection unit 8b of the second series, and the detection result is obtained. Is applied to the ceramic resonator 12 on the side of the second series tuning circuit 7b, and the resonator 12 outputs an output voltage corresponding to the paper thickness. First series and second series of ceramic resonators
12 produces an AM modulated wave from changes in the output voltage corresponding to these paper thicknesses, and uses this as a detection signal for the corresponding detection circuit 4
Add to a, 4b. That is, the first series ceramic resonator 12 multiplies the oscillation frequency f OSC by the resonance frequency change component Δf corresponding to the change in the paper thickness detected by the detection electrode 14a to obtain an AM modulated wave. Similarly, the second series ceramic resonator 12 multiplies the oscillation frequency f OSC by the resonance frequency change component Δf corresponding to the change in the paper thickness detected by the detection electrode 14b to obtain an AM modulated wave. In this embodiment, the oscillation frequency f OSC is a 1GH Z, a detection signal of the modulated wave is centered 1GH Z, becomes very high frequency signal having a bandwidth Fu corresponding to a change in paper thickness, the ultra A high frequency signal is applied from the ceramic resonator 12 of each series to the corresponding detection circuit 4a, 4b.
検波回路4a、4bではこの超高周波信号を包絡線検波を行
って紙厚検出の信号帯域（本実施例では3MHzの信号）に
変換する。この帯域変換された信号の一部は次の増幅回
路5a,5bによって増幅され、差動増幅器17に送られ、他
の一部の信号はAFC回路9a,9bに分岐供給される。AFC回
路9a,9bは例えば、紙１のしわや破れ等の外乱によって
同調点が紙厚検出の設定利得範囲から外れるのを補正
し、同調点を共振周波数曲線のゲーンの高い直線領域の
最適位置に調整する。The detection circuits 4a and 4b perform envelope detection on the ultra high frequency signal and convert it to a signal band for detecting the paper thickness (a signal of 3 MHz in this embodiment). A part of the band-converted signal is amplified by the next amplifier circuits 5a and 5b and sent to the differential amplifier 17, and another part of the signal is branched and supplied to the AFC circuits 9a and 9b. The AFC circuits 9a and 9b correct, for example, that the tuning point deviates from the set gain range of paper thickness detection due to disturbance such as wrinkles and tears of the paper 1, and the tuning point is set to the optimum position in the straight line area of the high gain of the resonance frequency curve. Adjust to.
作動増幅器17は各系列の増幅回路5a,5bから加えられる
信号の差を求め、その差動出力を図示されていない所望
の信号処理回路に加える。The operational amplifier 17 finds the difference between the signals applied from the amplifier circuits 5a and 5b of each series, and applies the differential output to a desired signal processing circuit (not shown).
第４図には差動増幅器17によって得られた差動出力の波
形例が示されており、これについて説明すると、例え
ば、第１図の実線で示す様に、走行通路領域２に１枚の
紙１が走行してきたとき、その紙１の先端Ａが検出電極
14aの直下に来たとき、検出電極14aと接地電極15との間
の静電容量の変化が電極検出部8aで検出され、電極検出
部8bでは静電容量の変化が検出されないから、第１の系
列の信号と第２の系列の信号との差動出力は、第４図
（ａ）に示すように、負の方向に突出するピークS1とし
て現れる。すなわち、第５図に示すように、検出電極14
a,14bと接地電極15間の幅をＬとし、１枚の紙の厚味を
ｌとすると、検出電極14a,14bと接地電極15間の静電容
量Ｃは、空間誘電率Ｅと紙の誘電率E1、および紙の厚味
nl（ｎは整数）と空間幅Ｌ−nlによって定められる。次
に、紙１の先端Ａが検出電極14bの直下に来ると、同様
に、電極検出部8bによって静電容量の変化が検出される
が、この静電容量の変化成分は電極検出部8aで検出され
る静電容量の変化成分と同一となるので、その差動出力
は０になり、パルスS1が正の方向に立ち下がる。さら
に、紙１が走行方向に移動して紙１の後端Ｃが検出電極
14aを通り過ぎると、電極検出部8aで検出される静電容
量が変化し、差動増幅器17での差動出力は第４図（ａ）
のS2のパルス波形として現れる。このパルス波形のS1と
S2のピーク電圧を分析することにより、紙厚が求めら
れ、また、パルス波形S1とS2との時間幅を分析すること
により紙の長さを求めることができる。FIG. 4 shows an example of the waveform of the differential output obtained by the differential amplifier 17, which will be explained. For example, as shown by the solid line in FIG. When the paper 1 is running, the leading edge A of the paper 1 is the detection electrode.
When it comes directly below 14a, a change in capacitance between the detection electrode 14a and the ground electrode 15 is detected by the electrode detection unit 8a, and no change in capacitance is detected by the electrode detection unit 8b. The differential output of the signal of the series and the signal of the second series appears as a peak S 1 protruding in the negative direction, as shown in FIG. That is, as shown in FIG.
When the width between a and 14b and the ground electrode 15 is L and the thickness of one sheet of paper is l, the electrostatic capacitance C between the detection electrodes 14a and 14b and the ground electrode 15 is the space permittivity E and the paper Dielectric constant E 1 , and paper thickness
It is defined by nl (n is an integer) and the space width L-nl. Next, when the leading edge A of the paper 1 comes directly under the detection electrode 14b, the change in the electrostatic capacitance is detected by the electrode detection unit 8b in the same manner. The change component of the electrostatic capacitance is detected by the electrode detection unit 8a. Since it is the same as the detected electrostatic capacitance change component, its differential output becomes 0, and the pulse S 1 falls in the positive direction. Further, the paper 1 moves in the traveling direction, and the rear end C of the paper 1 becomes the detection electrode.
When it passes 14a, the electrostatic capacitance detected by the electrode detection unit 8a changes, and the differential output of the differential amplifier 17 is shown in FIG. 4 (a).
Appears as the pulse waveform of S 2 . S 1 of this pulse waveform
By analyzing the peak voltage of the S 2, the sheet thickness is obtained, also, it is possible to determine the length of the paper by analyzing the time width of the pulse waveform S 1 and S 2.
次に、第１図の破線で示すように、紙１が２枚重なって
紙送りされたときには、第４図（ｂ）で示すように、ま
ず、紙の先端Ａが検出電極14aを通るときに、差動増幅
器17はSAのパルスの信号を出力し、紙の先端Ａが検出電
極14bに至ると差動出力は０になり、パルスSAは正の方
向に立ち下がる。そして、重なった紙の前端Ｂが検出電
極14aを通過するときに、SBのパルス波形が現れ、その
紙の先端Ｂが検出電極14bに至ると差動出力は０にな
り、パルスSBは立ち下がる。次に、紙の後端Ｃが検出電
極14aに来ると、SCのパルス波形が上方に突出して現れ
る。そして、紙の後端Ｃが検出電極14bに来ると差動出
力は０になり、パルスSCは下方に立ち下がる。次に、重
なった紙の後端Ｄが検出電極14aを過ぎ去るときに、SD
のパルス波形が現れる。パルス波形の高さは、紙の厚味
nl、正確には紙の厚味ｌを同一とすると、その枚数の影
響を受けて決まる。すなわち、第６図に示すように、静
電容量と紙の厚味は反比例の関係にあり、検出電極14a,
14bと接地電極15の間に紙がない場合l0の静電容量C0に
対し、紙が１枚のときC1、２枚のときC2となる。差動増
幅器17からのこれらの差動信号を分析することにより、
紙２枚送りの有無、紙厚、紙の乾湿状態、紙の長さおよ
び紙が２枚送りされたときの紙のずれ量等の検出を行う
ことができる。すなわち、紙の２枚送りの状態はパルス
波形SAに対してより大きなパルス波形SBが現れることに
より、検出される。またパルス波形SAとSBとのピーク値
の差VABを求めることにより紙厚が検出され、しかも、
このVABの大きさを分析することにより紙の乾湿状態を
見分けることができる。また、パルス波形SAとSCとの時
間幅により紙１の長さが求められる。また、パルス波形
SAとSBとの時間幅に基づいて２枚送りされる紙のずれ量
を求めることができる。この紙のずれ量の検出に際して
は、検出電極14aと14bとの間隔を接近させ、しかも、検
出電極14a,14bの電極面積を非常に小さくすれば、２枚
送りされる紙の微小ずれ量を高精度で求めることができ
る。Next, as shown by the broken line in FIG. 1, when two sheets of paper 1 are overlapped and fed, as shown in FIG. 4 (b), first, when the front end A of the paper passes through the detection electrode 14a. In addition, the differential amplifier 17 outputs a signal of pulse S A , and when the leading edge A of the paper reaches the detection electrode 14b, the differential output becomes 0, and the pulse S A falls in the positive direction. Then, when the front end B of the overlapped paper passes the detection electrode 14a, a pulse waveform of S B appears, and when the front end B of the paper reaches the detection electrode 14b, the differential output becomes 0, and the pulse S B becomes Get down. Next, when the trailing edge C of the paper reaches the detection electrode 14a, the pulse waveform of S C appears to project upward. Then, when the trailing edge C of the paper comes to the detection electrode 14b, the differential output becomes 0, and the pulse S C falls downward. Next, when the trailing edge D of the overlapped paper passes the detection electrode 14a, S D
The pulse waveform of appears. The height of the pulse waveform is the thickness of the paper
If nl, to be exact, the thickness l of the paper is the same, it is determined by the influence of the number of sheets. That is, as shown in FIG. 6, the capacitance and the thickness of the paper are in inverse proportion to each other.
When there is no paper between 14b and the ground electrode 15, the electrostatic capacity C 0 is l 0 , whereas when there is one paper, it is C 1 , and when it is two , it is C 2 . By analyzing these differential signals from the differential amplifier 17,
It is possible to detect the presence / absence of feeding two sheets of paper, the thickness of the paper, the dry / wet state of the paper, the length of the paper, and the amount of deviation of the paper when two sheets of paper are fed. That is, the two-sheet feeding state is detected by the appearance of a larger pulse waveform S B with respect to the pulse waveform S A. Also, the paper thickness is detected by obtaining the difference V AB between the peak values of the pulse waveforms S A and S B , and
By analyzing the size of this V AB , the dry and wet state of the paper can be identified. Further, the length of the paper 1 is obtained from the time width between the pulse waveforms S A and S C. Also, the pulse waveform
It is possible to obtain the amount of misalignment between the two sheets fed based on the time width between S A and S B. When detecting the deviation amount of the paper, if the distance between the detection electrodes 14a and 14b is made close and the electrode area of the detection electrodes 14a and 14b is made very small, the minute deviation amount of the two sheets fed will be small. It can be obtained with high accuracy.
本実施例によれば、走行通路領域２を通る紙１の紙厚を
非接触状態で検出するものであるから、紙１の走行速度
を高速にしてもこれに確実に追従して紙厚の変化や紙の
重なり等を正確に検出することが可能となる。According to the present embodiment, since the paper thickness of the paper 1 passing through the traveling passage area 2 is detected in a non-contact state, even if the traveling speed of the paper 1 is made high, the paper thickness is surely followed to detect the paper thickness. It is possible to accurately detect changes and paper overlaps.
また、本実施例は、検出電極14a,14bと接地電極15との
間を紙が通過することによる静電容量の微小変化を検出
し、発振回路６の発振周波数信号に対する同調回路7a,7
bの同調点の変化を利用して紙厚を検出するものである
から、装置構成を簡易とするにもかかわらず、高精度の
もとで目的とする紙厚の検出が可能となる。しかも、本
実施例では、第１の系列の同調回路7a側の検出信号と第
２の系列の同調回路7b側の検出信号との差の信号により
紙厚等の検出を行うものであるから、温度や湿度等の環
境変化の外乱成分がキャンセルされて取り除かれること
となり、S/N比の高い、かつ、信頼性の高い紙厚等の検
出が可能となる。Further, in the present embodiment, the minute changes in the electrostatic capacitance due to the paper passing between the detection electrodes 14a, 14b and the ground electrode 15 are detected, and the tuning circuits 7a, 7b for the oscillation frequency signal of the oscillation circuit 6 are detected.
Since the paper thickness is detected by utilizing the change in the tuning point of b, the target paper thickness can be detected with high accuracy despite the simplification of the device configuration. Moreover, in the present embodiment, the paper thickness and the like are detected by the signal of the difference between the detection signal of the first series tuning circuit 7a side and the detection signal of the second series tuning circuit 7b side. Disturbance components due to environmental changes such as temperature and humidity are canceled and removed, and it becomes possible to detect paper thickness and the like with a high S / N ratio and high reliability.
さらに、本実施例では、発振回路６の共振器と、同調回
路7a,7bの共振器とを共にセラミック共振器10,12により
構成しているから、Ｑを大きな値にすることが可能とな
る。しかも、セラミック共振器12の周囲部の回路、つま
り、インピーダンス変換回路6aと、インダクタンス素子
21とコンデンサ25の共振回路とを高インピーダンス回路
により構成しているから、セラミック共振器の動作時に
Ｑダンプを生じさせることがなく、高感度のもとで静電
容量の微小変化を検出することが可能となる。Further, in this embodiment, since the resonator of the oscillation circuit 6 and the resonators of the tuning circuits 7a and 7b are both constituted by the ceramic resonators 10 and 12, Q can be set to a large value. . Moreover, the circuit around the ceramic resonator 12, that is, the impedance conversion circuit 6a and the inductance element
Since the 21 and the resonance circuit of the capacitor 25 are composed of a high impedance circuit, it is possible to detect a minute change in the capacitance with high sensitivity without causing Q dump during the operation of the ceramic resonator. Is possible.
さらに、共振器をストリップラインを使用せずにセラミ
ック共振器10,12により構成したから、装置の超小型が
可能となる。Further, since the resonator is composed of the ceramic resonators 10 and 12 without using the strip line, the device can be made extremely compact.
なお、本発明は上記実施例に限定されることはなく、様
々な実施の態様を採り得る。例えば、上記実施例では、
発振回路６の共振器と同調回路7a,7bの共振器とを共に
セラミック共振器10,12により構成したが、これら一方
の共振器または両方の共振器をストリップラインで構成
することも可能である。これらの共振器に関し、発振回
路６の共振器と同調回路7a,7bの共振器とを温度特性の
同じ材料で構成すれば、温度安定性の良い紙厚検出装置
が得られることになる。The present invention is not limited to the above embodiments, and various modes of implementation can be adopted. For example, in the above embodiment,
The resonator of the oscillation circuit 6 and the resonators of the tuning circuits 7a and 7b are both ceramic resonators 10 and 12, but one or both of these resonators may be formed by strip lines. . With respect to these resonators, if the resonator of the oscillation circuit 6 and the resonators of the tuning circuits 7a and 7b are made of materials having the same temperature characteristics, a paper thickness detecting device having good temperature stability can be obtained.
本発明は、紙の走行通路領域に紙と非接触状態で前後方
向に一対の電極検出部を配置し、この電極検出部を紙が
非接触状態で通ることによる電極検出領域の静電容量の
変化を利用して紙厚等を検出するものであるから、紙の
走行速度を高速にしても、これに確実に追従して紙厚を
検出することができる。According to the present invention, a pair of electrode detection units are arranged in the front-rear direction in a non-contact state with the paper in a traveling path region of the paper, and electrostatic capacitance of the electrode detection region due to the paper passing through the electrode detection units in the non-contact state Since the change is used to detect the paper thickness and the like, even if the traveling speed of the paper is high, the paper thickness can be reliably detected by following this.
また、本発明は、紙厚の変化に対応する静電容量の変化
を利用して発振回路の固定の発振周波数に対して同調回
路の共振周波数の同調点を偏倚させて紙厚の検出信号を
得る方式であるから、装置構成を簡易にするにもかかわ
らず微小紙厚の変化を高精度のもとで正確に検出するこ
とができ、その上、装置コストも安価にできる。しか
も、紙厚の検出を、第１の系列と第２の系列の各同調回
路から得られる信号の差動出力によって求める方式であ
るから、外乱成分がキャンセルされて取り除かれること
となり、これにより、紙厚、紙の重なり、紙の長さ、紙
の乾湿状態、重なった紙のずれ量等の情報を高感度、高
精度、かつ、高信頼性のもとで検出することができ、技
術的価値は非常に大きい。さらに、本発明は、１個の発
振回路から第１の系列と第２の系列の各同調回路に固定
の発振周波数を加えるようにしているので、第１の系列
の同調回路の共振周波数が同調する固定周波数と第２の
系列の同調回路の共振周波数が同調する固定周波数とは
ずれがなく同一の値となり、これにより、第１の系列と
第２の系列の各同調回路の同調基準となる固定周波数の
確実な整合をとることができ、両同調回路から出力され
る検出信号の差によって得られる紙厚検出信号の精度お
よび信頼性を格段に高めることができる。Further, according to the present invention, by utilizing the change in capacitance corresponding to the change in paper thickness, the tuning point of the resonance frequency of the tuning circuit is biased with respect to the fixed oscillation frequency of the oscillation circuit to detect the paper thickness detection signal. Since it is a method of obtaining, it is possible to accurately detect a change in the minute paper thickness with high accuracy in spite of the simplification of the apparatus configuration, and further, the apparatus cost can be reduced. Moreover, since the paper thickness is detected by the differential output of the signals obtained from the tuning circuits of the first series and the second series, the disturbance component is canceled and removed. It is possible to detect information such as paper thickness, paper overlap, paper length, paper dry / wet condition, and misaligned amount of overlapped paper with high sensitivity, high accuracy, and high reliability. The value is enormous. Further, according to the present invention, since a fixed oscillation frequency is applied to each tuning circuit of the first series and the second series from one oscillation circuit, the resonance frequency of the tuning circuit of the first series is tuned. Fixed frequency and the resonance frequency of the tuning circuit of the second series are the same as the fixed frequency to be tuned and have the same value. As a result, a fixed reference frequency for tuning circuits of the first series and the second series. The frequency can be surely matched, and the accuracy and reliability of the paper thickness detection signal obtained by the difference between the detection signals output from both tuning circuits can be significantly improved.
第１図は本発明に係る紙厚検出装置の一実施例を示すブ
ロック図、第２図は同実施例装置の具体的な一系列の回
路図、第３図は同実施例における紙厚検出作用の説明
図、第４図は同実施例における紙厚検出の差動出力の波
形説明図、第５図は紙厚変化と静電容量の変化の関係を
示す説明図、第６図は静電容量と紙厚の関係を示す説明
図、第７図は従来の一般的な紙厚検出装置の説明図であ
る。 １……紙、２……走行通路領域、３……ポテンショメー
タ、3a……回転軸、3b……接触針、4a,4b……検波回
路、5a,5b……増幅回路、６……発振回路、7a,7b……同
調回路、8a,8b……電極検出部、9a,9b……AFC回路、10
……セラミック共振器、11a,11b……センサ回路、12…
…セラミック共振器、13……トランジスタ、14a,14b…
…検出電極、15……接地電極、16……分配器、17……差
動増幅器、21……インダクタンス素子、22……ダイオー
ド、23……コンデンサ、24……抵抗器、25……結合コン
デンサ、27……トランジスタ。FIG. 1 is a block diagram showing an embodiment of the paper thickness detecting device according to the present invention, FIG. 2 is a specific circuit diagram of the device of the embodiment, and FIG. 3 is a paper thickness detecting device in the same embodiment. FIG. 4 is an explanatory diagram of a differential output waveform of paper thickness detection in the same embodiment, FIG. 5 is an explanatory view showing a relation between paper thickness change and capacitance change, and FIG. FIG. 7 is an explanatory view showing the relationship between the capacitance and the paper thickness, and FIG. 7 is an explanatory view of a conventional general paper thickness detecting device. 1 ... Paper, 2 ... Traveling passage area, 3 ... Potentiometer, 3a ... Rotating shaft, 3b ... Contact needle, 4a, 4b ... Detection circuit, 5a, 5b ... Amplification circuit, 6 ... Oscillation circuit , 7a, 7b ...... Tuning circuit, 8a, 8b ...... Electrode detector, 9a, 9b ...... AFC circuit, 10
...... Ceramic resonator, 11a, 11b …… Sensor circuit, 12…
… Ceramic resonator, 13… Transistor, 14a, 14b…
… Detection electrode, 15 …… Grounding electrode, 16 …… Distributor, 17 …… Differential amplifier, 21 …… Inductance element, 22 …… Diode, 23 …… Capacitor, 24 …… Resistor, 25 …… Coupling capacitor , 27 …… Transistor.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭61−116603（ＪＰ，Ａ) 特開 昭61−209361（ＪＰ，Ａ) 実開 昭54−3976（ＪＰ，Ｕ) ─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-61-116603 (JP, A) JP-A-61-209361 (JP, A) Actually developed JP-A-54-3976 (JP, U)
Claims (1)
対して非接触状態で設けられる第１および第２の２系列
の検出電極と；固定の発振周波数を発振出力する１個の
発振回路と；前記発振回路とは別個独立の共振器を備
え、前記第１の系列の検出電極によって検出される静電
容量の変化を受けて前記発振回路の固定の発振周波数に
対する共振周波数の同調点を変化させ、この同調点の変
化に対応した検出信号を出力する第１の系列の同調回路
と；前記発振回路および第１の系列の同調回路とは別個
独立の共振器を備え、前記第２の系列の検出電極によっ
て検出される静電容量の変化を受けて前記発振回路の固
定の発振周波数に対する共振周波数の同調点を変化さ
せ、この同調点の変化に対応した検出信号を出力する第
２の系列の同調回路と；前記第１の系列の同調回路から
の検出信号と第２の系列の同調回路からの検出信号との
差の信号を出力する出力回路と；を有する紙厚検出装
置。1. A first and a second series of detection electrodes, which are provided in front of and behind a traveling path region of the paper and are in a non-contact state with the paper; and one for oscillating and outputting a fixed oscillation frequency. An oscillating circuit; a resonator independent of the oscillating circuit, tuning the resonant frequency with respect to a fixed oscillating frequency of the oscillating circuit in response to a change in capacitance detected by the first series of detection electrodes A first series tuning circuit for changing a point and outputting a detection signal corresponding to the change of the tuning point; a resonator independent of the oscillation circuit and the first series tuning circuit; A tuning point of the resonance frequency with respect to the fixed oscillation frequency of the oscillation circuit is changed in response to a change in the capacitance detected by the detection electrodes of the second series, and a detection signal corresponding to the change of the tuning point is output. 2 series tuning circuit Sheet thickness detecting device having: detection signal and an output circuit for outputting a signal of a difference between the detection signal from the tuning circuit of the second series from the tuning circuit of the first series.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2035571A JPH0752083B2 (en) | 1990-02-16 | 1990-02-16 | Paper thickness detector |
| US07/654,425 US5198777A (en) | 1990-02-14 | 1991-02-12 | Paper thickness detecting apparatus having a resonator with a resonance point set by a capacitance detecting unit |
| EP91301173A EP0442727B1 (en) | 1990-02-14 | 1991-02-13 | Paper thickness detecting apparatus |
| DE69122895T DE69122895T2 (en) | 1990-02-14 | 1991-02-13 | Apparatus for determining the paper thickness |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2035571A JPH0752083B2 (en) | 1990-02-16 | 1990-02-16 | Paper thickness detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03238303A JPH03238303A (en) | 1991-10-24 |
| JPH0752083B2 true JPH0752083B2 (en) | 1995-06-05 |
Family
ID=12445446
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2035571A Expired - Fee Related JPH0752083B2 (en) | 1990-02-14 | 1990-02-16 | Paper thickness detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0752083B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8028990B2 (en) | 2007-07-26 | 2011-10-04 | Fujitsu Limited | Paper thickness detecting apparatus with applying electrodes |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2481002B (en) * | 2010-06-04 | 2015-01-14 | Plastic Logic Ltd | Determining layer thickness |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS543976U (en) * | 1977-06-13 | 1979-01-11 | ||
| JPS61116603A (en) * | 1984-11-12 | 1986-06-04 | Fujitsu Ltd | Detector |
| JPS61209361A (en) * | 1985-03-13 | 1986-09-17 | Nec Corp | Method for measuring electrostatic capacity |
-
1990
- 1990-02-16 JP JP2035571A patent/JPH0752083B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8028990B2 (en) | 2007-07-26 | 2011-10-04 | Fujitsu Limited | Paper thickness detecting apparatus with applying electrodes |
| US20110309572A1 (en) * | 2007-07-26 | 2011-12-22 | Fujitsu Limited | Paper thickness detecting apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03238303A (en) | 1991-10-24 |
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| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |