JP2004361148A - Water content measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water content measuring instrument capable of measuring the water content of a material to be measured with high precision. <P>SOLUTION: The water content measuring instrument is equipped with a reflecting plate 20 for reflecting the irradiation light I emitted from a light source 1 toward a detector 4. The detector 4 detects not only the intensity of reflected light occurring from paper in a state that the paper is fed to the surface of the reflecting plate 20 but also the intensity of the irradiation light I reflected as reflected light RO by the reflecting plate 20 in a state that the paper is fed from the reflecting plate 20. By operating the water content of the paper on the basis of the detection result of reflected light and the detection result of the irradiation light I (reflected light RO), for example, when the intensity of the irradiation light I is changed with the elapse of time by the deterioration or the like of the light source 1, the intensity change of the irradiation light I is added to correct the water content Q of the paper. As a result, an operational precision is enhanced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００３９】
本実施の形態に係る含水量測定装置では、照射光Ｉを反射光Ｒ０としてディテクタ４へ向けて反射させる反射板２０を備え、ディテクタ４が反射光Ｒの強度と共に反射光Ｒ０の強度を検出する機能も兼ねるようにしたので、ディテクタ４において反射光Ｒ１，Ｒ０１の強度を検出し、その反射光Ｒ１，Ｒ０１の検出結果に基づいて含水量Ｑを演算することが可能になる。この場合には、照射光Ｉの強度を不変の定数として含水量Ｑを演算していた従来の含水量測定装置とは異なり、例えば光源１の劣化等に起因して照射光Ｉの強度が経時的に変化した場合に、その経時変化後の照射光Ｉの強度を実測した上で、反射光Ｒ１の強度と共に照射光Ｉの強度変化（反射光Ｒ０１の強度変化）を加味して紙Ｐの反射率ＲＤが演算される。したがって、本実施の形態では、照射光Ｉの強度変化の観点において含水量Ｑの測定精度に誤差を及ぼし得る要因が取り除かれ、その誤差が排除されるため、紙Ｐの含水量Ｑを高精度に測定することができる。
【００４０】
特に、本実施の形態では、紙Ｐの含水量Ｑの測定精度が向上する点に基づき、含水量測定装置を搭載しているコピー機やプリンタ等において、紙Ｐの含水量Ｑに応じて印画条件を制御することにより、印画品質の高品質化を図ることができる。
【００４１】
また、本実施の形態では、光源１から照射された照射光Ｉを反射散乱させることにより紙Ｐへ導く積分球２を備えるようにしたので、この積分球２の散乱面２Ｍにおいて反射散乱された照射光Ｉが紙Ｐへ等方的に照射される。この場合には、積分球２を備えておらず、照射光Ｉが紙Ｐへ等方的に照射されない場合とは異なり、反射光Ｒの強度がほぼ完全散乱面に基づく角度分布となり、すなわち紙Ｐに垂直な軸と反射光Ｒの進行方向との間の角度の余弦に対してその反射光Ｒの強度がほぼ比例するため、紙Ｐの反射率ＲＤとして絶対反射率を演算することが可能になる。したがって、本実施の形態では、反射光Ｒの強度の角度分布に起因する誤差が小さくなるため、この観点においても含水量Ｑの測定精度の向上に寄与することができる。この場合には、特に、光源１から照射された照射光Ｉが積分球２の内部に閉じ込められる結果、紙Ｐへ照射される照射光Ｉの照射効率が向上するため、ディテクタ４の検出強度を十分に確保することができる。
【００４２】
また、本実施の形態では、反射光Ｒ，Ｒ０を波長分離するフィルタ６を備えるようにしたので、このフィルタ６による波長分離作用を利用して、反射光Ｒ，Ｒ０のうち、含水量Ｑの測定に有用な１．８μｍ以上の波長域の光（反射光Ｒ１，Ｒ０１）が選択的にフィルタ６を通過し、ディテクタ４へ到達する。したがって、ディテクタ４において反射光Ｒ１，Ｒ０１の強度を安定かつ容易に検出することができる。
【００４３】
また、本実施の形態では、ガラス製のレンズ５を使用するようにしたので、ガラスの赤外線吸収特性、すなわち４．０μｍ以上の波長域の赤外線光を吸収する特性を利用して、反射光Ｒ，Ｒ０がレンズ５を通過する際に、それらの反射光Ｒ，Ｒ０のうちの４．０μｍ以上の波長域の赤外線光がレンズ５において吸収される。したがって、熱輻射に起因した演算誤差を誘発する不要な波長域の光を除いた反射光Ｒ，Ｒ０がフィルタ６へ導かれるため、この不要な赤外線光の存在に起因して含水量Ｑの演算結果に誤差が含まれることを防止することができる。
【００４４】
また、本実施の形態では、上記したフィルタ６の波長分離作用およびレンズ５の赤外線吸収特性に基づき、実質的に１．８μｍ以上４．０μｍ未満の比較的狭い範囲内の波長域の光（反射光Ｒ１，Ｒ０１）を利用して含水量Ｑが演算されるため、上記「従来の技術」の項において説明した２種類の波長域の赤外線光（被水吸収性の高い１μｍ以上の波長域の光および被水吸収性の低い１μｍ未満の波長域の光）を使用した従来の含水量測定装置と比較して、含水量Ｑの測定精度がより向上する。なぜなら、１μｍ以上の比較的広い範囲の波長域の光を利用した従来の場合には、水により吸収される光の波長域に対して全体の波長域が大きすぎるため、全体の波長域の反射光エネルギーに対して被水吸収性の波長域の反射光エネルギーが極めて小さくなり、その反射光強度の変化を検出しにくくなるのに対して、１．８μｍ以上４．０μｍ未満の比較的狭い範囲内の波長域の光を利用した本実施の形態の場合には、従来の場合と比較して、全体の波長域の反射光エネルギーに対して被水吸収性の波長域の反射光エネルギーが大きくなり、その反射光強度の変化を検出しやすくなるからである。
【００４５】
［第２の実施の形態］
次に、本発明の第２の実施の形態について説明する。
【００４６】
図４は、本実施の形態に係る含水量測定装置の概略構成を表している。なお、図４では、上記第１の実施の形態において説明した構成要素と同一の構成要素に同一の符号を付している。
【００４７】
この含水量測定装置は、上記第１の実施の形態と同様に、反射光Ｒの検出結果および照射光Ｉの検出結果に基づいて含水量Ｑを演算するものであり、例えば、図４に示したように、反射板２０を備えていない上、積分球２の側方に開口部２ＫＡと対向するように開口部２ＫＤが設けられ、この開口部２ＫＤに対応して照射光強度検出用のレンズ５１、フィルタ６１およびディテクタ４１（照射光強度検出手段）が配置されていると共に、積分球２に開口部２ＫＡを通じて他の積分球２１が連結され、その積分球２１内に光源１が配置されている点を除き、上記第１の実施の形態と同様の構成（図１〜図３参照）を有している。
【００４８】
積分球２１は、照射光Ｉを反射して散乱させることにより開口部２ＫＡを通じて積分球２へ導くものであり、例えば、積分球２と同様の構成を有し、すなわち球２１Ｇの内面に散乱面２１Ｍを構成する散乱膜２１Ｓが設けられた構成を有している。この積分球２１の寸法（例えば内径）は、例えば、積分球２の寸法よりも小さくなっている。この積分球２１の内部には、光源１と開口部２ＫＡとの間の位置にバフル７１が配置されている。
【００４９】
レンズ５１は、照射光Ｉを集光するものであり、例えば、レンズ５と同様の構成を有している。なお、レンズ５１を設けるか否かは自由に設定可能である。フィルタ６１は、照射光Ｉを波長分離するものであり、例えば、フィルタ６と同様の構成を有している。ディテクタ４１は、照射光Ｉの強度を検出するものであり、すなわち光源１から照射された照射光Ｉの強度を開口部２ＫＤを通じて直接的に検出するようになっている。ここでいう「直接的」とは、光源１から照射された照射光Ｉを反射板２０において反射光Ｒ０として反射させたのちに検出していた上記第１の実施の形態とは異なり、反射板２０において反射した反射光Ｒ０以外の光を検出する（照射光Ｉをそのまま検出する）という意味である。このディテクタ４１は、例えば、ディテクタ４と同様の構成を有している。
【００５０】
この含水量測定装置では、紙Ｐが搬送された状態において、光源１から照射光Ｉが照射されて反射光Ｒが生じると、図４に示したように、上記第１の実施の形態において説明した光学的原理に基づいて、フィルタ６の波長分離作用を利用して反射光Ｒのうちの１．８μｍ以上の波長域の光（反射光Ｒ１）がディテクタ４において検出されると共に、照射光Ｉが開口部２ＫＤを通じてレンズ５１を経由してフィルタ６１へ導かれることにより、上記した反射光Ｒと同様に、フィルタ６１の波長分離作用を利用して照射光Ｉのうちの１．８μｍ以上の波長域の光（照射光Ｉ１）がディテクタ４１において検出される。これにより、上記第１の実施の形態と同様の演算手順を経て、図３に示したコントローラ９により、ディテクタ４，４１の検出結果に基づいて含水量Ｑが演算される。
【００５１】
本実施の形態に係る含水量測定装置では、反射光Ｒ１の強度を検出するディテクタ４に加えて、照射光Ｉ１の強度を検出するディテクタ４１を備えるようにしたので、ディテクタ４において反射光Ｒ１の強度を検出すると共にディテクタ４１において照射光Ｉ１の強度を検出し、その反射光Ｒ１の検出結果と共に照射光Ｉ１の検出結果に基づいて含水量Ｑを演算することが可能になる。したがって、上記第１の実施の形態と同様の作用により、紙Ｐの含水量Ｑを高精度に測定することができる。
【００５２】
特に、本実施の形態では、積分球２に連結された積分球２１内に光源１を配置するようにしたので、積分球２に積分球２１を連結させずに、その積分球２内に光源１を配設した場合とは異なり、照射光Ｉの大部分が積分球２，２１において反射散乱されたのちにディテクタ４１へ入射する。したがって、照射光Ｉの強度の角度分布に起因する誤差を小さくすることが可能になるため、この観点においても含水量Ｑの測定精度の向上に寄与することができる。
【００５３】
なお、本実施の形態に係る含水量測定装置に関する上記以外の詳細な作用、動作および効果等は、上記第１の実施の形態と同様である。
【００５４】
［第３の実施の形態］
次に、本発明の第３の実施の形態について説明する。
【００５５】
図５および図６は、本実施の形態に係る含水量測定装置の概略構成を表しており、図５は反射光強度および透過光強度検出時の状態を示し、図６は照射光強度検出時の状態を示している。なお、図５および図６では、上記第１の実施の形態において説明した構成要素と同一の構成要素に同一の符号を付している。
【００５６】
この含水量測定装置は、反射光Ｒの検出結果および照射光Ｉの検出結果に基づいて含水量Ｑを演算していた上記第１の実施の形態とは異なり、反射光Ｒの検出結果および照射光Ｉの検出結果と共に透過光Ｔの検出結果に基づいて含水量Ｑを演算するものであり、非透過性の紙Ｐの含水量Ｑだけでなく、透過性（例えば薄厚や低密度）の紙Ｐの含水量Ｑも測定するために使用されるものである。この含水量測定装置は、例えば、図５および図６に示したように、反射板２０を備えていない上、積分球２の下方に配置され、上方に設けられた開口部２２ＫＡおよび側方に設けられた開口部２２ＫＢを有する積分球２２と、この開口部２２ＫＢに対応して配置された透過光強度検出用のレンズ５２、フィルタ６２およびディテクタ４２（透過光強度検出手段）とを新たに備えている点を除き、上記第１の実施の形態の含水量測定装置（図１〜図３参照）と同様の構成を有している。
【００５７】
積分球２２は、紙Ｐを透過した透過光Ｔと共に積分球２を経由して導かれた照射光Ｉを反射して散乱させることにより開口部２２ＫＢを通じてディテクタ４２へ導くものであり、例えば、積分球２と同様の構成を有し、すなわち球２２Ｇの内面に散乱面２２Ｍを構成する散乱膜２２Ｓが設けられた構成を有している。この積分球２２の寸法（例えば内径）は、例えば、積分球２の寸法とほぼ同様である。
【００５８】
レンズ５２は、透過光Ｔを集光するものであり、例えば、レンズ５と同様の構成を有している。フィルタ６２は、透過光Ｔと共に照射光Ｉを波長分離するものであり、例えば、フィルタ６と同様の構成を有している。ディテクタ４２は、透過光Ｔの強度と共に照射光Ｉの強度を検出するものであり、例えば、ディテクタ４と同様の構成を有している。
【００５９】
この含水量測定装置では、図５に示したように、積分球２，２２間の位置まで紙Ｐが搬送された状態において、光源１から照射光Ｉが照射されると、紙Ｐにおいて反射光Ｒおよび透過光Ｔが生じる。この反射光Ｒは、上記第１の実施の形態において説明した光学的原理に基づき、フィルタ６へ導かれて波長分離されるため、その反射光Ｒのうちの１．８μｍ以上の波長域の光（反射光Ｒ１）がディテクタ４において検出される。また、透過光Ｔは、開口部２２ＫＡを通じて積分球２２へ導かれ、その積分球２２の散乱面２２Ｍにおいて反射散乱されることにより開口部２２ＫＢを通じてレンズ５２を経由してフィルタ６２へ導かれたのち、そのフィルタ６２において波長分離されるため、上記した反射光Ｒと同様に、透過光Ｔのうちの１．８μｍ以上の波長域の光（透過光Ｔ１）がディテクタ４２において検出される。一方、図６に示したように、積分球２，２２間の位置から紙Ｐが搬送された状態において、光源１から照射光Ｉが照射されると、その照射光Ｉが積分球２を経由して積分球２２へ導かれるため、上記した透過光Ｔと同様に、照射光Ｉのうちの１．８μｍ以上の波長域の光（照射光Ｉ１）がディテクタ４２において検出される。
【００６０】
この場合には、図３に示したコントローラ９は、以下の動作手順により、ディテクタ４，４２の検出結果に基づいて含水量Ｑを演算する。すなわち、まず、ディテクタ４２において検出された照射光Ｉ１の強度とディテクタ４において検出された反射光Ｒ１の強度とに基づいて反射率ＲＤを演算する。続いて、照射光Ｉの強度とディテクタ４２において検出された透過光Ｔ１の強度とに基づいて透過率ＴＤを演算する。続いて、反射率ＲＤと透過率ＴＤとに基づいて、吸収率・散乱率比ＡＤ／ＳＤを演算する。最後に、メモリ８から検量線データＣを読み出し、この検量線データＣに基づいて吸収率・散乱率比ＡＤ／ＳＤに対応する含水量Ｑを特定する。これにより、ディテクタ４，４２の検出結果に基づいて含水量Ｑが演算される。
【００６１】
ここで、透過率ＴＤを考慮した場合のコントローラ９による吸収率・散乱率比ＡＤ／ＳＤの演算原理について説明する。すなわち、上記したＫｕｂｅｌｋａ−Ｍｕｎｋの散乱モデルに基づく式１を応用すれば、反射率ＲＤ、吸収率ＡＤ、散乱率ＳＤおよび透過率ＴＤの間に下記の式２の関係が成立する。式２中のＲ∞は、紙Ｐの厚さを無限大としたときの反射率であり、Ｒｇは積分球２２に応じた固有の反射率（既知）である。したがって、式２を利用すれば、反射率ＲＤと透過率ＴＤとに基づいて反射率Ｒ∞を演算することにより、その反射率Ｒ∞に基づいて吸収率・散乱率比ＡＤ／ＳＤを算出することが可能になるのである。なお、式２では、反射率ＲＤを簡略化して「Ｒ」と示し、透過率ＴＤを簡略化して「Ｔ」と示している。
【００６２】
【式２】

【００６３】
本実施の形態に係る含水量測定装置では、反射光Ｒ１の強度を検出するディテクタ４に加えて、透過光Ｔ１の強度および照射光Ｉ１の強度を検出するディテクタ４２を備えるようにしたので、ディテクタ４において反射光Ｒ１の強度を検出すると共にディテクタ４２において透過光Ｔ１の強度および照射光Ｉ１の強度を検出し、その反射光Ｒ１の検出結果と共に透過光Ｔ１の検出結果および照射光Ｉの検出結果に基づいて含水量Ｑを演算することが可能になる。この場合には、透過光Ｔ１の強度が無視できないほどに大きな紙Ｐの含水量Ｑを測定する際に、透過光Ｔ１の強度を加味せずに反射光Ｒ１の強度および照射光Ｉ１の強度のみに基づいて含水量Ｑを演算する場合と比較して、透過光Ｔ１の強度を加味した分だけ紙Ｐの厚さに対する反射率ＲＤの依存性が補正される。すなわち、上記した式２を利用し、透過率ＴＤを加味して反射率ＲＤを紙Ｐの厚さが十分に大きい場合に得られる反射率Ｒ∞に変換した上で、その反射率Ｒ∞に基づいて含水量Ｑが演算されるため、紙Ｐの厚さの影響が排除され、含水量Ｑの演算精度が向上する。したがって、本実施の形態では、非透過性の紙Ｐの含水量Ｑに加えて、透過光Ｔの影響が無視できないほどに大きな透過性の紙Ｐの含水量Ｑも高精度に測定することができる。
【００６４】
特に、本実施の形態では、透過光Ｔを反射散乱させる積分球２２を備えるようにしたので、積分球２２を備えていない場合と比較して透過光Ｔの捕捉率が高まり、透過光Ｔの強度の角度分布に起因する誤差が小さくなる。したがって、この観点においても含水量Ｑの測定精度の向上に寄与することができる。
【００６５】
なお、本実施の形態に係る含水量測定装置に関する上記以外の詳細な作用、動作および効果等は、上記第１の実施の形態と同様である。
【００６６】
［第４の実施の形態］
次に、本発明の第４の実施の形態について説明する。
【００６７】
図７は、本実施の形態に係る含水量測定装置の概略構成を表している。なお、図７では、上記第３の実施の形態において説明した構成要素と同一の構成要素に同一の符号を付している。
【００６８】
この含水量測定装置は、上記第３の実施の形態と同様に、反射光Ｒの検出結果および照射光Ｉの検出結果と共に透過光Ｔの検出結果に基づいて含水率Ｑを演算するものであり、例えば、図７に示したように、新たに積分球２，２２間に半透過反射板３２（選択的透過手段）を備えている点を除き、上記第３の実施の形態の含水量測定装置（図５，図６および図３参照）と同様の構成を有している。
【００６９】
半透過反射板３２は、紙Ｐを透過した光のうちの一部の光を透過光Ｔとして選択的に透過させることにより積分球２２を経由してディテクタ４２へ導くと共に、その紙Ｐを透過した光のうちの残りの光を反射させることにより積分球２を経由してディテクタ４へ導くものであり、例えば、ポリエチレンやフッ素系プラスチックにより構成されている。この半透過反射板３２の表面は粗面仕上げされており、その表面において光が散乱反射するように構成されているのが好ましく、あるいは半透過反射板３２が多孔質のプラスチック製であり、その内部で光が散乱反射するように構成されているのが好ましい。この半透過反射板３２の散乱率、反射率および厚さは既知である。
【００７０】
この含水量測定装置では、半透過反射板３２上に紙Ｐが搬送された状態において、光源１から照射光Ｉが照射されると、紙Ｐにおいて反射光Ｒおよび透過光Ｔが生じる。この透過光Ｔとは、紙Ｐを透過した光のうちの一部の光、すなわち半透過反射板３２を選択的に透過して積分球２２に導かれた光である。また、反射光Ｒとは、紙Ｐを透過した光のうちの残りの光、すなわち半透過反射板３２において反射されて再び紙Ｐを経由して積分球２に導かれた光と、紙Ｐにおいて反射した光との混合光である。この反射光Ｒは、上記第１の実施の形態において説明した光学的原理に基づき、フィルタ６へ導かれて波長分離されるため、その反射光Ｒのうちの１．８μｍ以上の波長域の光（反射光Ｒ１）がディテクタ４において検出される。一方、透過光Ｔは、上記第３の実施の形態において説明した光学的原理に基づき、フィルタ６２へ導かれて波長分離されるため、その透過光Ｔのうちの１．８μｍ以上の波長域の光（透過光Ｔ１）がディテクタ４２において検出される。なお、図示はしないが、この含水量測定装置では、半透過反射板３２上から紙Ｐが搬送された状態において、上記第３の実施の形態において図６を参照して説明した場合と同様に、照射光Ｉのうちの１．８μｍ以上の波長域の光（照射光Ｉ１）がディテクタ４２において検出される。これにより、上記第３の実施の形態と同様の演算手順を経て、図３に示したコントローラ９により、ディテクタ４，４２の検出結果に基づいて含水量Ｑが演算される。
【００７１】
本実施の形態に係る含水量測定装置では、紙Ｐを透過した光のうちの一部の光を透過光Ｔとして選択的に透過させる半透過反射板３２を備えるようにしたので、ディテクタ４２において透過光Ｔ１の強度および照射光Ｉの強度を検出すると共に、ディテクタ４において反射光Ｒ１の強度を検出し、反射光Ｒ１の検出結果と共に透過光Ｔ１の検出結果および照射光Ｉの強度に基づいて含水量Ｑを演算することが可能になる。したがって、この場合においても透過光Ｔの強度を加味して吸収率・散乱率比ＡＤ／ＳＤが演算され、この吸収率・散乱率比ＡＤ／ＳＤに基づいて含水量Ｑが演算されるため、上記第３の実施の形態と同様の作用により、紙Ｐの含水量Ｑを高精度に測定することができる。
【００７２】
なお、本実施の形態に係る含水量測定装置に関する上記以外の詳細な作用、動作および効果等は、上記第３の実施の形態と同様である。
【００７３】
［第５の実施の形態］
次に、本発明の第５の実施の形態について説明する。
【００７４】
図８および図９は、本実施の形態に係る含水量測定装置の概略構成を表しており、図８は紙Ｐの搬送前の状態を示し、図９は紙Ｐの搬送後の状態を示している。なお、図８および図９では、上記第３の実施の形態において説明した構成要素と同一の構成要素に同一の符号を付している。
【００７５】
この含水量測定装置は、紙Ｐの表裏面に関して反射光Ｒの強度および透過光Ｔの強度を検出し、上記第３の実施の形態と同様に、反射光Ｒの検出結果および照射光Ｉの検出結果と共に透過光Ｔの検出結果に基づいて含水量Ｑを演算するものである。この含水量測定装置は、例えば、図８および図９に示したように、上記第３の実施の形態において説明した含水量測定装置（図５，図６および図３参照）により構成された２つの含水量測定部１００Ａ，１００Ｂを備え、これらの２つの含水量測定部１００Ａ，１００Ｂが互いに上下反転された状態で紙Ｐの進行方向（矢印Ｙ）に沿って配列された構成を有している。
【００７６】
紙Ｐは、対向する一対の面ＰＸ（表面），ＰＹ（裏面）を有しており、例えば、裏面ＰＹに印画面Ｇを有している。この印画面Ｇは、例えば、コピー機やプリンタ等によりトナー等を使用して形成された文字や画像などである。この紙Ｐは、図示しない搬送機構を利用して、含水量測定部１００Ａに対応する位置ＴＡから含水量測定部１００Ｂに対応する位置ＴＢまで搬送されるようになっている。
【００７７】
この含水量測定装置に、印画面Ｇを有する裏面ＰＹが下方を向くように紙Ｐが投入された場合、位置ＴＡにおいて、含水量測定部１００Ａのディテクタ４は、紙Ｐの裏面ＰＹに関する反射光Ｒの強度を検出する機能を担い、ディテクタ４２は、紙Ｐの表面ＰＸ側に位置して透過光Ｔの強度を検出する機能を担う。一方、位置ＴＢにおいて、含水量測定部１００Ｂのディテクタ４は、紙Ｐの表面ＰＸに関する反射光Ｒの強度を検出する機能を担い、ディテクタ４２は、紙Ｐの裏面ＰＹ側に位置して透過光Ｔの強度を検出する機能を担う。
【００７８】
この含水量測定装置では、まず、図８に示したように、位置ＴＡに紙Ｐが搬送された状態において、含水量測定部１００Ａの光源１から照射光Ｉが照射されると、紙Ｐの裏面ＰＹにおいて生じた反射光Ｒがフィルタ６へ導かれて波長分離されるため、その反射光Ｒのうちの１．８μｍ以上の波長域の光（反射光Ｒ１）がディテクタ４において検出されると共に、紙Ｐを透過した透過光Ｔがフィルタ６２へ導かれて波長分離されるため、その透過光Ｔのうちの１．８μｍ以上の波長域の光（透過光Ｔ１）がディテクタ４２において検出される。続いて、図９に示したように、位置ＴＡから位置ＴＢまで紙Ｐが搬送された状態において、含水量測定部１００Ｂの光源１から照射光が照射されると、紙Ｐの表面ＰＸにおいて生じた反射光Ｒがフィルタ６へ導かれて波長分離されるため、その反射光Ｒのうちの１．８μｍ以上の波長域の光（反射光Ｒ１）がディテクタ４において検出されると共に、紙Ｐを透過した透過光Ｔがフィルタ６２へ導かれて波長分離されるため、その透過光Ｔのうちの１．８μｍ以上の波長域の光（透過光Ｔ１）がディテクタ４２において検出される。なお、図示はしないが、この含水量測定装置では、位置ＴＡから紙Ｐが搬送された状態において、上記第３の実施の形態において図６を参照して説明した場合と同様に、含水量測定部１００Ａのディテクタ４２において照射光Ｉのうちの１．８μｍ以上の波長域の光（照射光Ｉ１）が検出されると共に、位置ＴＢから紙が搬送された状態においても同様に、含水量測定部１００Ｂのディテクタ４２において照射光Ｉ１が検出される。
【００７９】
この場合には、図３に示したコントローラ９は、例えば、含水量測定部１００Ａにおいて検出したデータ、すなわち紙Ｐの裏面ＰＹに関する反射特性を考慮した反射光Ｒ１の強度、透過光Ｔ１の強度および照射光Ｉの強度と、含水量測定部１００Ｂにおいて検出したデータ、すなわち紙Ｐの表面ＰＸに関する反射特性を考慮した反射光Ｒ１の強度、透過光Ｔ１の強度および照射光Ｉの強度とに基づいて吸収率・散乱率比ＡＤ／ＳＤを演算したのち、この吸収率・散乱率比ＡＤ／ＳＤに基づいて検量線データＣを利用して含水量Ｑを特定する。
【００８０】
本実施の形態に係る含水量測定装置では、紙Ｐの裏面ＰＹ（印画面Ｇ）に関する反射特性を考慮した反射光Ｒ１の強度を検出する含水量測定部１００Ａと、紙Ｐの表面ＰＸに関する反射特性を考慮した反射光Ｒ１の強度を検出する含水量測定部１００Ｂとを備えるようにしたので、以下の理由により、裏面ＰＹに印画面Ｇを有する紙Ｐの含水量Ｑを高精度に測定することができる。
【００８１】
すなわち、近年のコピー機やプリンタ等の使用状況を考慮すると、未印画の紙に限らず、印画済みの紙を使用する場合も多い。これは、印画済みの紙を処分せずに再利用し、未印画面（印画面と反対側の面）に新たに印画することを目的としたものである。しかしながら、紙の一面に画像形成用のトナー等が存在すると、このトナー等の存在に起因して紙の散乱率や吸収率が変化し得るため、含水量を高精度に測定しにくくなる。
【００８２】
この点に関して、本実施の形態では、上記したように、含水量測定部１００Ａにおいて、紙Ｐの裏面ＰＹ（印画面Ｇ）に関する反射特性を考慮した反射光Ｒ１の強度を検出すると共に、含水量測定部１００Ｂにおいて、紙Ｐの表面ＰＸに関する反射特性を考慮した反射光Ｒ１の強度を検出し、これらの２つの反射光Ｒ１の強度を含んで含水量Ｑを演算するようにしたので、単に紙Ｐの一方の面（ＰＸまたはＰＹ）のみに関して含水量Ｑを演算する場合とは異なり、印画面Ｇの存在に起因する光の散乱率や吸収率の差異に起因する光学的誤差が補正され、含水量Ｑの演算精度が向上する。したがって、本実施の形態では、裏面ＰＹに印画面Ｇを有する紙Ｐの含水量Ｑを高精度に測定することが可能になるのである。
【００８３】
なお、上記では、裏面ＰＹに印画面Ｇを有する紙Ｐの含水量Ｑを測定するために本実施の形態の含水量測定装置を使用するようにしたが、必ずしもこれに限られるものではなく、例えば、いずれの面ＰＸ，ＰＹにも印画面Ｇを有しない紙Ｐ（未使用の紙）の含水量Ｑを測定するために本実施の形態の含水量測定装置を使用するようにしてもよい。この場合においても、紙Ｐの各面ＰＸ，ＰＹに関する反射特性の差異を考慮して、含水量Ｑを高精度に測定することができる。
【００８４】
本実施の形態に係る含水量測定装置に関する上記以外の作用、動作、効果および変形は上記第３の実施の形態と同様であるので、その説明を省略する。
【００８５】
［第６の実施の形態］
次に、本発明の第６の実施の形態について説明する。
【００８６】
図１０および図１１は、本実施の形態に係る含水量測定装置の概略構成を表しており、図１０は紙Ｐの反転前の状態を示し、図１１は紙Ｐの反転後の状態を示している。なお、図１０および図１１では、上記第３の実施の形態において説明した構成要素と同一の構成要素に同一の符号を付している。
【００８７】
この含水量測定装置は、上記第５の実施の形態と同様に、紙Ｐの表裏面に関して反射光Ｒの強度および透過光Ｔの強度を検出し、反射光Ｒの検出結果および照射光Ｉの検出結果と共に透過光Ｔの検出結果に基づいて含水量Ｑを演算するものであり、例えば、図１０および図１１に示したように、紙Ｐの表裏を反転させる反転機構３４を新たに備えている点を除き、上記第３の実施の形態の含水量測定装置（図５，図６および図３参照）と同様の構成を有している。この反転機構３４は、例えば、紙Ｐを搬送するための搬送用ローラや反転させるための反転用ローラなどを含んで構成されている。
【００８８】
この含水量測定装置では、図１０に示したように、印画面Ｇを有する裏面ＰＹが上方を向くように紙Ｐが搬送された状態において、光源１から照射光Ｉが照射されると、上記第３の実施の形態において説明した光学的原理に基づき、紙Ｐの裏面ＰＹにおいて生じた反射光Ｒがフィルタ６へ導かれて波長分離されるため、その反射光Ｒのうちの１．８μｍ以上の波長域の光（反射光Ｒ１）がディテクタ４において検出されると共に、紙Ｐを透過した透過光Ｔがフィルタ６２へ導かれて波長分離されるため、その透過光Ｔのうちの１．８μｍ以上の波長域の光（透過光Ｔ１）がディテクタ４２において検出される。続いて、図１１に示したように、反転機構３４により紙Ｐの表裏が反転され、印画面Ｇを有する裏面ＰＹが下方を向いた状態において光源１から照射光Ｉが照射されると、紙Ｐの表面ＰＸにおいて生じた反射光Ｒがフィルタ６へ導かれて波長分離されるため、その反射光Ｒのうちの１．８μｍ以上の波長域の光（反射光Ｒ１）がディテクタ４において検出されると共に、紙Ｐを透過した透過光Ｔがフィルタ６２へ導かれて波長分離されるため、その透過光Ｔのうちの１．８μｍ以上の波長域の光（透過光Ｔ１）がディテクタ４２において検出される。なお、図示はしないが、この含水量測定装置では、紙Ｐの搬送前の状態において、上記第３の実施の形態において図６を参照して説明した場合と同様に、照射光Ｉのうちの１．８μｍ以上の波長域の光（照射光Ｉ１）がディテクタ４２において検出される。
【００８９】
この場合には、図３に示したコントローラ９は、例えば、紙Ｐの反転前にディテクタ４，４２において検出したデータ、すなわち紙Ｐの裏面ＰＹに関する反射特性を考慮した反射光Ｒ１の強度、透過光Ｔ１の強度および照射光Ｉの強度と、紙Ｐの反転後に検出したデータ、すなわち紙Ｐの表面ＰＸに関する反射特性を考慮した反射光Ｒ１の強度、透過光Ｔ１の強度および照射光Ｉの強度とに基づいて吸収率・散乱率比ＡＤ／ＳＤを演算したのち、この吸収率・散乱率比ＡＤ／ＳＤに基づいて検量線データＣを利用して含水量Ｑを特定する。
【００９０】
本実施の形態に係る含水量測定装置では、紙Ｐの表裏を反転させる反転機構３４を備えるようにしたので、この反転機構３４を利用して、紙Ｐの裏面ＰＹに関する反射特性を考慮した反射光Ｒ１の強度と表面ＰＸに関する反射特性を考慮した反射光Ｒ１の強度とを検出し、これらの２つの反射光Ｒ１の強度を含んで含水量Ｑを演算することが可能になる。したがって、上記第５の実施の形態と同様の作用により含水量Ｑの演算精度が向上するため、裏面ＰＹに印画面Ｇを有する紙Ｐの含水量Ｑを高精度に測定することができる。
【００９１】
特に、本実施の形態では、反転機構３４による紙Ｐの反転機構を利用することにより、上記第５の実施の形態において説明したように実質的に２つの含水量測定装置（含水量測定部１００Ａ，１００Ｂ）を組み合わせて使用せずに、１つの含水量測定装置のみを使用して含水量Ｑを演算することが可能になる。したがって、上記第５の実施の形態と比較して、装置の小型化および低コスト化を図ることができる。
【００９２】
なお、本実施の形態に係る含水量測定装置に関する上記以外の効果および変形は上記第３の実施の形態と同様であるので、その説明を省略する。
【００９３】
以上、第１〜第６の実施の形態としていくつかの含水量測定装置について説明したが、含水量Ｑの測定精度を向上させることが可能な限り、各含水量測定装置の構成は自由に変更可能である。
【００９４】
具体的には、上記各実施の形態では、光源１として、１．８μｍ以上の波長域の赤外線光を含む照射光Ｉを照射するものを使用するようにしたが、必ずしもこれに限られるものではなく、例えば、その１．８μｍ以上の波長域の赤外線光のみを照射光Ｉとして照射するものを使用するようにしてもよい。この種の光源１としては、例えば、１．９μｍ近傍の波長域の赤外線光のみを照射可能なＬＥＤ（Ｌｉｇｈｔ Ｅｍｉｔｔｉｎｇ Ｄｉｏｄｅ）やＬＤ（Ｌａｓｅｒ Ｄｉｏｄｅ ）などが挙げられる。この場合においても、上記各実施の形態と同様の効果を得ることができる。
【００９５】
また、上記第１の実施の形態（図１および図２参照）では、反射光Ｒのうちの１．８μｍ以上の波長域の光（反射光Ｒ１）および反射光Ｒ０のうちの１．８μｍ以上の波長域の光（反射光Ｒ０１）を検出するディテクタ４のみを備え、そのディテクタ４の検出結果に基づいて含水量Ｑを演算するようにしたが、必ずしもこれに限られるものではなく、例えば、図１２および図１３に示したように、ディテクタ４に加えて、１．８μｍ未満の波長域の光（反射光Ｒ２，Ｒ０２）を検出するディテクタ４３を備えると共に、これらのディテクタ４，４３へ導かれる光（反射光Ｒ，Ｒ０）を１．８μｍ以上の波長域の光（反射光Ｒ１，Ｒ０１）と１．８μｍ未満の波長域の光（反射光Ｒ２，Ｒ０２）とに分離する光学的分離手段を備え、ディテクタ４，４３の双方の検出結果に基づいて含水量Ｑを演算するようにしてもよい。なお、上記した「反射光Ｒ，Ｒ０を１．８μｍ以上の波長域の光と１．８μｍ未満の波長域の光とに分離する」という表現は、１．８μｍの波長を基準（境界）として厳密に１．８μｍ以上の波長域の光と１．８μｍ未満の波長域の光とに分離する場合に限らず、全体中において１．８μｍ以上の波長域の光が占める割合が大きい光（１．８μｍ以上の波長域の光を大部分含み、１．８μｍ未満の波長域の光も僅かに含む光）と全体中において１．８μｍ未満の波長域の光が占める割合が大きい光（１．８μｍ未満の波長域の光を大部分含み、１．８μｍ未満の波長域の光も僅かに含む光）とに分離する場合も含む意味である。この旨は、後述する照射光Ｉ（Ｉ１，Ｉ２）および透過光Ｔ（Ｔ１，Ｔ２）についても同様である。このディテクタ４３は、例えば、シリコンフォトダイオード、ゲルマニウムフォトダイオード、インジウムガリウムヒ素合金フォトダイオードまたは熱起電力型素子などにより構成されている。また、光学的分離手段は、例えば、フィルタ６を傾けてハーフミラーとして使用したものである。なお、必要に応じて、ディテクタ４３と共に、例えば薄膜干渉フィルタ、バンドパスフィルタまたは回折格子などの波長制限用の分光手段を組み合わせて使用してもよい。
【００９６】
この含水量測定装置では、光源１から照射光Ｉが照射されると、図１２に示したように、反射光Ｒがフィルタ６へ導かれて波長分離され、その反射光Ｒのうちの被水吸収性の高い１．８μｍ以上の波長域の光（反射光Ｒ１）がディテクタ４において検出され、かつ被水吸収性の低い１．８μｍ未満の波長域の光（反射光Ｒ２）がディテクタ４３において検出されると共に、図１３に示したように、反射光Ｒと同様に反射光Ｒ０がフィルタ６へ導かれて波長分離され、その反射光Ｒ０のうちの１．８μｍ以上の波長域の光（反射光Ｒ０１）がディテクタ４において検出され、かつ１．８μｍ未満の波長域の光（反射光Ｒ０２）がディテクタ４３において検出される。なお、例えば、ディテクタ４３の分光感度特性によっては、そのディテクタ４３において１．８μｍ以上の波長域の光も検出され得るが、その場合には、ディテクタ４，４３の検出結果に基づいて、ディテクタ４３に対する１．８μｍ以上の波長域の光の強度の寄与分が演算されることにより、その演算結果に基づいてディテクタ４３の検出値が補正された上で、１．８μｍ未満の波長域の光の強度が算出される。
【００９７】
この場合には、以下の演算原理に基づき、散乱率ＳＤが既知でない場合においても紙Ｐの含水量を演算することが可能である。すなわち、上記したＫｕｂｅｌｋａ−Ｍｕｎｋの散乱モデルに基づく関係式が、１．８μｍ以上の波長域の光（反射光Ｒ１，Ｒ０１）に関してｆ（ＲＤ１）＝ＡＤ１／ＳＤ１と表され、一方、１．８μｍ未満の波長域の光（反射光Ｒ２，Ｒ０２）に関してｆ（ＲＤ２）＝ＡＤ２／ＳＤ２と表されるとする。これらのＲＤ２、ＡＤ２およびＳＤ２は、それぞれ紙Ｐ自体（水を除く）の反射率、吸収率および散乱率に相当する。この場合には、反射光Ｒ１，Ｒ２の双方に関して散乱率が等しく（ＳＤ１＝ＳＤ２）、かつ吸収率ＡＤ２が既知であれば、ｆ（ＲＤ１）／ｆ（ＲＤ２）＝ＡＤ１／ＡＤ２の関係に基づいて吸収率比ＡＤ１／ＡＤ２を演算した上、この吸収率比ＡＤ１／ＡＤ２に基づいて紙Ｐの含水量Ｑを特定することが可能になる。この場合には、被水吸収性の高い反射光Ｒ１，Ｒ０１の強度と被水吸収性の低い反射光Ｒ２，Ｒ０２の強度との間の差異に基づいて散乱率ＳＤの変動による影響が排除されるため、その吸収率比ＡＤ１／ＡＤ２の演算精度が向上する。したがって、紙Ｐの含水量Ｑを極めて高精度に測定することができる。なお、図１２および図１３に示した含水量測定装置に関する上記以外の特徴は、図１および図２に示した含水量測定装置と同様である。参考までに、例えば、紙Ｐに代えて、材質が一定なパルプなどの含水量Ｑを測定する場合には、上記した吸収率ＡＤ２は一定となるので、吸収率比ＡＤ１／ＡＤ２を含水量Ｑと直接対応づけることも可能である。
【００９８】
特に、図１２および図１３に示した含水量測定装置に関して、上記したように、１．８μｍ以上の波長域の赤外線光のみを照射光Ｉとして照射する光源１を使用した場合には、例えば、この光源１とは別個に、１．８μｍ未満の波長域の赤外線光のみを照射光Ｉとして照射する他の光源を使用するようにしてもよい。この「他の光源」としては、例えば、１．８μｍ未満の波長域の赤外線光のみを選択的に照射可能なＬＤ（Ｌａｓｅｒ Ｄｉｏｄｅ ）などが挙げられる。この場合においても、同様の効果を得ることができる。
【００９９】
なお、図１２および図１３に示した変形例は、上記第１の実施の形態に限らず、他の第２〜第６の実施の形態にも適用可能である。
【０１００】
具体的には、上記第２の実施の形態に適用した場合には、図１４に示したように、フィルタ６１を傾けてハーフミラーとして使用した上で、ディテクタ４１に加えて新たにディテクタ４４を備えるようにすれば、照射光Ｉのうちの１．８μｍ以上の波長域の光（照射光Ｉ１）がディテクタ４１において検出されると共に、１．８μｍ未満の波長域の光（照射光Ｉ２）がディテクタ４４において検出されるため、図１２および図１３に示した場合と同様の作用により、紙Ｐの含水量Ｑを極めて高精度に測定することができる。
【０１０１】
また、上記第３の実施の形態に適用した場合には、図１５および図１６に示したように、フィルタ６２を傾けてハーフミラーとして使用した上で、ディテクタ４２に加えて新たにディテクタ４５を備えるようにすれば、図１５に示したように、透過光Ｔの検出時に、その透過光Ｔのうちの１．８μｍ以上の波長域の光（透過光Ｔ１）がディテクタ４２において検出され、かつ１．８μｍ未満の波長域の光（透過光Ｔ２）がディテクタ４５において検出されると共に、図１６に示したように、照射光Ｉの検出時に、その照射光Ｉのうちの１．８μｍ以上の波長域の光（照射光Ｉ１）がディテクタ４２において検出され、かつ１．８μｍ未満の波長域の光（照射光Ｉ２）がディテクタ４５において検出される。したがって、図１２および図１３を参照して説明した反射光Ｒ１，Ｒ２と同様の作用により、透過光Ｔ１，Ｔ２間の強度および照射光Ｉ１，Ｉ２間の強度に基づいて吸収率・散乱率比ＡＤ１／ＳＤ，ＡＤ２／ＳＤが演算されたのちに吸収率比ＡＤ１／ＡＤ２が演算され、その誤差となる要因が排除された吸収率比ＡＤ１／ＡＤ２に基づいて含水量Ｑが特定されるため、紙Ｐの含水量Ｑを極めて高精度に測定することができる。
【０１０２】
また、上記第４の実施の形態に適用した場合には、図１７に示したように、透過光Ｔのうちの１．８μｍ以上の波長域の光（透過光Ｔ１）がディテクタ４２において検出されると共に、１．８μｍ未満の波長域の光（透過光Ｔ２）がディテクタ４５において検出されるため、図１５および図１６に示した場合と同様の作用により、紙Ｐの含水量Ｑを極めて高精度に測定することができる。
【０１０３】
また、図示はしないが、上記第５および第６の実施の形態に適用すれば、上記第２〜第４の実施の形態に適用した場合と同様に、含水量Ｑの測定精度を向上させることができる。
【０１０４】
また、上記第１の実施の形態（図１および図２参照）では、紙Ｐの含水量Ｑを測定する上で、紙Ｐが反射板２０上を搬送されるため、その反射板２０を固定するようにしたが、必ずしもこれに限られるものではなく、例えば、紙Ｐが反射板２０上を搬送されない場合、例えば紙Ｐがコピー機やプリンタ等のトレー内に保管されるものである場合には、紙Ｐに代えて、反射板２０を測定位置（図１および図２に示した反射板２０の位置）とその測定位置から離れた退避位置との間で移動させるようにしてもよい。この場合においても、必要に応じて反射板２０において照射光Ｉをディテクタ４へ向けて反射させることが可能になるため、同様の効果を得ることができる。
【０１０５】
また、上記第１の実施の形態では、光源１から照射された照射光Ｉを反射光Ｒ０としてディテクタ４へ向けて反射させる部材として反射板２０を使用するようにしたが、必ずしもこれに限られるものではなく、反射板２０と同様に照射光Ｉを反射し得る限り、その反射板２０を他の部材に置き換えてもよい。この「他の部材」としては、例えば、積分球２の開口部２ＫＢに対応した位置に開口部を有する他の積分球などが挙げられる。
【０１０６】
また、上記第２の実施の形態（図４参照）では、上記第１の実施の形態において説明した反射板２０を設けないようにしたが、必ずしもこれに限られるものではなく、例えば、反射板２０を設けるようにしてもよい。この場合の反射板２０は、照射光Ｉを反射光Ｒ０として反射させる機能を担っていた上記第１の実施の形態とは異なり、僅かながらでも紙Ｐが透過性を有する場合に、その紙Ｐを透過した光をディテクタ４へ向けて反射させる機能を担うものである。この場合には、紙Ｐの透過性の有無に関わらずに、ディテクタ４へ導かれる光の割合がほぼ一定に維持されるため、含水量Ｑの演算精度をより向上させることができる。
【０１０７】
また、上記第２の実施の形態では、積分球２のうち、開口部２ＫＡに対向する位置に開口部２ＫＤを設け、この開口部２ＫＤに対応してレンズ５１、フィルタ６１およびディテクタ４１を配置させるようにしたが、必ずしもこれに限られるものではなく、例えば、図１８に示したように、開口部２ＫＡに対向しない位置に開口部２ＫＤを設けた、この開口部２ＫＤに対応してレンズ５１、フィルタ６１およびディテクタ４１を配置させるようにしてもよい。この場合には、積分球２において反射された照射光Ｉに加えて、バフル７１において反射された照射光Ｉもディテクタ４１において検出し得る上記第２の実施の形態とは異なり、バフル７１において反射された割合を少なくし、積分球２において反射散乱された割合を多くした状態で照射光Ｉをディテクタ４１において検出することが可能になるため、含水量Ｑの演算精度をより向上させることができる。なお、図１８では、含水量測定装置の平面構成を模式的に表しており、図４に示した一連の構成要素のうちの光源１、積分球２，２１（開口部２ＫＡ，２ＫＤ）、ディテクタ４１、レンズ５１、フィルタ６１およびバフル７１のみを示している。
【０１０８】
また、上記第１〜第６の実施の形態において説明した含水量測定装置の構成および図１２〜図１８に示した変形例は、上記したようにそれぞれ単独で含水量測定装置に適用されるようにしてもよいし、あるいは適宜組み合わされて含水量測定装置に適用されるようにしてもよい。具体的には、例えば、図１９に示したように、第２の実施の形態において説明した構成（図４参照）と第３の実施の形態において説明した構成（図５参照）とを組み合わせるようにしてもよい。この場合においても、上記各実施の形態および各変形例と同様の効果を得ることができる。
【０１０９】
また、上記各実施の形態および各変形例では、本発明の含水量測定装置を使用して紙の含水量を測定する場合について説明したが、必ずしもこれに限られるものではなく、例えば、本発明の含水量測定装置を使用すれば、紙以外の他の被測定物の含水量を測定することも可能である。この「他の被測定物」としては、例えば、布や、土や、パンまたは麺などの生地や、海苔または茶などの食品等が挙げられる。この場合においても、上記各実施の形態と同様の効果を得ることができる。
【０１１０】
【実施例】
次に、本発明に関する具体的な実施例について説明する。
【０１１１】
本発明の一連の含水量測定装置を代表して、上記第１の実施の形態として図１および図２に示した含水量測定装置（以下、単に「本発明の第１の含水量測定装置」という。）を使用して紙Ｐの含水量Ｑを測定したところ、図２０に示した結果が得られ、第１の実施の形態に関する変形例として図１２および図１３に示した含水量測定装置（以下、単に「本発明の第２の含水量測定装置」という。）を使用して紙Ｐの含水量Ｑを測定したところ、図２１に示した結果が得られた。図２０は吸収率・散乱率比と含水量との相関を表しており、「横軸」はＫｕｂｅｌｋａ−Ｍｕｎｋの関数を利用して求められる吸収率・散乱率比ＡＤ／ＳＤを示し、「縦軸」は含水量Ｑ（質量％）を示している。また、図２１は吸収率比と含水量との相関を表しており、「横軸」はＫｕｂｅｌｋａ−Ｍｕｎｋの関数を利用して求められる吸収率比ＡＤ１／ＡＤ２を示し、「縦軸」は含水量Ｑ（質量％）を示している。図２０および図２１に示した「○」は、紙Ｐとして株式会社ＮＢＳリコー製のＭＹ ＲＥＣＹＣＬＥ ＰＡＰＥＲ １００Ｗ 商品Ｎｏ．９０２０１０ を使用した場合に関する結果を示し、「□」は、他の紙Ｐとしてプラス株式会社製のコピーペーパー（中性紙）ＣＲ−２２０を使用した場合に関する結果を示している。
【０１１２】
含水量測定装置としては、積分球２として微細な表面凹凸構造を有する球２Ｇの内面に金製の散乱膜２Ｓが設けられたものを使用すると共に、光源１としてフィラメント電球を使用した。含水量Ｑを測定する際には、光源１を稼働させた状態でディテクタ４，４３において検出された光の強度（反射光Ｒ１と背景輻射に起因する光とが混合された混合光の強度）と、光源１を停止させた状態でディテクタ４，４３において検出された光の強度（背景輻射に起因する光の強度）との差分を、背景輻射の影響分を除いた反射光Ｒ１の強度とすることにより、その背景輻射の影響を排除して含水量Ｑを演算した。
【０１１３】
図２０に示した結果から判るように、本発明の第１の含水量測定装置を使用して含水量Ｑを測定したところ、紙質の異なるいずれの紙Ｐに関しても、Ｋｕｂｅｌｋａ−Ｍｕｎｋの関数から求められた吸収率・散乱率比ＡＤ／ＳＤが増加するにしたがって含水量Ｑの実測値が増加した。この場合には、紙質によっては若干のばらつきが見られたものの、吸収率・散乱率比ＡＤ／ＳＤと含水量Ｑとの間にほぼ比例関係が認められた。このことから、本発明の第１の含水量測定装置を使用すれば、紙Ｐの含水量Ｑを高精度に測定可能であることが確認された。
【０１１４】
また、図２１に示した結果から判るように、本発明の第２の含水量測定装置を使用して含水量Ｑを測定したところ、いずれの紙Ｐに関しても吸収率比ＡＤ１／ＡＤ２が増加するにしたがって含水量Ｑの実測値が増加した。この場合には、紙質に関係せずに、吸収率比ＡＤ１／ＡＤ２と含水量Ｑとの間に十分な比例関係が認められた。このことから、本発明の第２の含水量測定装置を使用すれば、紙Ｐの含水量Ｑをより高精度に測定可能であることが確認された。
【０１１５】
【発明の効果】
以上説明したように、本発明に係る含水量測定装置によれば、光源から照射された照射光の強度を検出する照射光強度検出手段を備え、照射光強度検出手段の検出結果および反射光強度検出手段の検出結果に基づいて被測定物の含水量を演算するようにしたので、例えば光源の劣化等に起因する照射光の強度変化を加味して含水量が演算される。したがって、反射光の強度と共に照射光の強度変化も加味して被測定物の反射率が演算されるため、被測定物の含水量を高精度に測定することができる。
【０１１６】
また、上記の他、本発明に係る含水量測定装置では、光源から照射された照射光を反射して散乱させることにより被測定物へ導く反射散乱手段を備えるようにすれば、反射光の強度の角度分布の観点において含水量の測定精度に誤差を及ぼし得る要因が取り除かれ、その誤差が小さくなるため、被測定物の含水量をより高精度に測定することができる。
【０１１７】
また、本発明に係る含水量測定装置では、被測定物を透過した透過光の強度を検出する透過光強度検出手段を備え、照射光強度検出手段の検出結果および反射光強度検出手段の検出結果と共に透過光強度検出手段の検出結果に基づいて含水量を演算するようにすれば、その透過光の強度を加味した分だけ被測定物の厚さに対する反射率の依存性が補正され、含水量の演算精度が向上するため、透過光の影響が無視できないほどに大きな被測定物の含水量をより高精度に測定することができる。
【０１１８】
また、本発明に係る含水量測定装置では、照射光強度検出手段、反射光強度検出手段および透過光強度検出手段へ導かれる光のうちの１．８μｍ以上の波長域の光を選択的に透過させる光学フィルタを備えるようにすれば、この光学フィルタによる波長分離作用を利用して、照射光、反射光および透過光のうちの含水量の測定に有用な１．８μｍ以上の波長域の光が照射光強度検出手段、反射光強度検出手段および透過光強度検出手段へそれぞれ導かれるため、照射光、反射光および透過光の強度を安定かつ容易に検出することができる。
【０１１９】
また、本発明に係る含水量測定装置では、照射光強度検出手段、反射光強度検出手段および透過光強度検出手段へ導かれる光を１．８μｍ以上の波長域の光と１．８μｍ未満の波長域の光とに分離する光学的分離手段を備え、これらの照射光強度検出手段、反射光強度検出手段および透過光強度検出手段が、それぞれ１．８μｍ以上の波長域の光の強度と１．８μｍ未満の波長域の光の強度とを別個に検出するようにすれば、被水吸収性の高い１．８μｍ以上の波長域の光の強度と被水吸収性の低い１．８μｍ未満の波長域の光の強度との間の差異に基づいて散乱率の変動による影響が排除されることにより演算精度が向上するため、被測定物の含水量を極めて高精度に測定することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態に係る含水量測定装置の反射光強度検出時の概略構成を表す断面図である。
【図２】図１に示した含水量測定装置の照射光強度検出時の概略構成を表す断面図である。
【図３】図１および図２に示した含水量測定装置のブロック構成を表すブロック図である。
【図４】本発明の第２の実施の形態に係る含水量測定装置の概略構成を表す断面図である。
【図５】本発明の第３の実施の形態に係る含水量測定装置の反射光強度および透過光強度検出時の概略構成を表す断面図である。
【図６】図５に示した含水量測定装置の照射光強度検出時の概略構成を表す断面図である。
【図７】本発明の第４の実施の形態に係る含水量測定装置の概略構成を表す断面図である。
【図８】本発明の第５の実施の形態に係る含水量測定装置の紙搬送前の概略構成を表す断面図である。
【図９】図８に示した含水量測定装置の紙搬送後の概略構成を表す断面図である。
【図１０】本発明の第６の実施の形態に係る含水量測定装置の紙反転前の概略構成を表す断面図である。
【図１１】図１０に示した含水量測定装置の紙反転後の概略構成を表す断面図である。
【図１２】本発明の第１の実施の形態に係る含水量測定装置に関する変形例（反射光強度検出時）を説明するための断面図である。
【図１３】図１２に示した含水量測定装置（照射光強度検出時）を説明するための断面図である。
【図１４】本発明の第２の実施の形態に係る含水量測定装置に関する変形例を説明するための断面図である。
【図１５】本発明の第３の実施の形態に係る含水量測定装置に関する変形例（反射光強度および透過光強度検出時）を説明するための断面図である。
【図１６】図１５に示した含水量測定装置（照射光強度検出時）を説明するための断面図である。
【図１７】本発明の第４の実施の形態に係る含水量測定装置に関する変形例を説明するための断面図である。
【図１８】本発明の第２の実施の形態に係る含水量測定装置に関する他の変形例を説明するための平面図である。
【図１９】本発明の含水量測定装置に関する他の変形例を説明するための断面図である。
【図２０】本発明の含水量測定装置に関する吸収率・散乱率比と含水量との相関を表す図である。
【図２１】本発明の他の含水量測定装置に関する吸収率比と含水量との相関を表す図である。
【符号の説明】
１…光源、２，２１，２２…積分球、２ＫＡ〜２ＫＤ，２２ＫＡ，２２ＫＢ…開口部、２Ｇ，２１Ｇ，２２Ｇ…球、２Ｍ，２１Ｍ，２２Ｍ…散乱面、２Ｓ，２１Ｓ，２２Ｓ…散乱膜、４，４１〜４５…ディテクタ、５…レンズ、６，６１，６２…フィルタ、７，７１…バフル、８…メモリ、９…コントローラ、１０…アンプ、１１…Ａ／Ｄ変換器、２０…反射板、３２…半透過反射板、３４…反転機構、１００Ａ，１００Ｂ…含水量測定部、ＡＤ…吸収率、ＡＤ／ＳＤ…吸収率・散乱率比Ｃ…検量線データ、Ｉ（Ｉ１，Ｉ２）…照射光、Ｇ…印画面、Ｐ…紙、ＰＸ…表面、ＰＹ…裏面、Ｒ０（Ｒ０１，Ｒ０２），Ｒ（Ｒ１，Ｒ２）…反射光、ＲＤ…反射率、ＳＤ…散乱率、Ｔ（Ｔ１，Ｔ２）…透過光、Ｑ…含水量。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a water content measuring device used for measuring the water content of an object to be measured such as paper.
[0002]
[Prior art]
In recent years, a water content measuring device has been used to measure the water content of an object to be measured such as paper. As this water content measuring device, for example, the intensity of reflected light generated when irradiating an object to be measured is detected, and the water content is measured using the fact that the intensity of the reflected light changes according to the water content. What calculates is known.
[0003]
Specifically, for example, light in two wavelength ranges from the light source to the object to be measured is light having a high water absorbency of 1 μm or more and light having a low water absorbency of less than 1 μm. And by detecting the intensity of the reflected light using two types of detection means having detection sensitivity in each wavelength range, the intensity of the light in the two wavelength ranges included in the reflected light is detected. 2. Description of the Related Art A water content measuring device that calculates a water content based on a relationship is known (for example, see Patent Document 1). This water content measuring device does not require a mechanism (a turret-type selector having a plurality of optical filters) for wavelength-separating the light emitted from the light source.
[0004]
[Patent Document 1]
JP 2000-283916 A
[0005]
Also, for example, light of three wavelengths from the light source to the object to be measured, that is, light of one infrared absorption wavelength (light having a high water absorbability) and light of two infrared comparison wavelengths (light of an infrared absorption wavelength) (Light having low water absorbability corresponding to the shorter wavelength side or the longer wavelength side) and the intensity of the reflected light generated when the light is irradiated, and the three wavelengths of light included in the reflected light are detected. There is known a water content measuring device that calculates a water content by correcting an error (an error caused by factors other than light absorption by water) based on a relationship between the intensities (for example, see Patent Document 2). . Specifically, in this water content measuring device, after extrapolating the reflectance of the light of the infrared comparison wavelength to calculate the scattering of the light of the infrared absorption wavelength, the scattering and the reflection of the light of the infrared absorption wavelength are calculated. By calculating the absorption rate based on the rate, the water content of the measured object is specified based on the absorption rate. In this water content measuring device, an error caused by disturbance (surface roughness of the measured object, etc.) is corrected.
[0006]
[Patent Document 2]
JP-A-03-11538
[0007]
[Problems to be solved by the invention]
By the way, in order to measure the water content of an object to be measured with high accuracy using a water content measurement device, it is necessary to remove as much as possible a factor that may cause an error in the measurement accuracy of the water content and to reduce the error. There is. In this regard, the above-described conventional water content measurement device is useful, but it can be said that there is still room for improvement in the measurement accuracy of the water content measurement device in consideration of the need for further improvement in measurement accuracy. In particular, in the conventional water content measuring device, for example, when the water content is calculated after fixing the intensity of the light emitted from the light source as a constant, for example, the light intensity due to the deterioration of the light source, etc. If the water content decreases, the water content contains an error corresponding to the decrease in the light intensity, so that it becomes difficult to measure the water content with high accuracy.
[0008]
The present invention has been made in view of such a problem, and an object of the present invention is to provide a water content measuring device capable of measuring the water content of an object to be measured with high accuracy.
[0009]
[Means for Solving the Problems]
The water content measuring device according to the present invention includes a light source, an irradiation light intensity detecting unit that detects the intensity of irradiation light emitted from the light source to the object to be measured, and detects the intensity of light reflected by the object to be measured. The apparatus comprises a reflected light intensity detecting means, and a calculating means for calculating the water content of the measured object based on at least the detection result of the irradiation light intensity detecting means and the detection result of the reflected light intensity detecting means.
[0010]
In the water content measuring device according to the present invention, the irradiation light is irradiated from the light source to the object to be measured, and when the reflected light is generated in the object to be measured, the intensity of the irradiation light is detected by the irradiation light intensity detecting means, and the reflected light is reflected. The light intensity detecting means detects the intensity of the reflected light. Then, the calculating means calculates the water content of the measured object based on at least the detection result of the irradiation light intensity detecting means and the detection result of the reflected light intensity detecting means. The reflectance of the measured object is calculated in consideration of not only the intensity of the reflected light but also a change in the intensity of the irradiation light due to, for example, deterioration of the light source, and the accuracy of calculating the water content is improved.
[0011]
In the water content measuring device according to the present invention, the irradiation light intensity detecting means is different from the reflected light intensity detecting means, and the intensity of the irradiation light may be directly detected, or the irradiation light may be reflected. A reflection unit for reflecting the light toward the light intensity detection unit is provided.The reflection light intensity detection unit also functions as an irradiation light intensity detection unit, and indirectly detects the intensity of the irradiation light via the reflection unit. Is also good.
[0012]
In particular, the water content measuring device according to the present invention may be provided with a reflection / scattering unit that guides the irradiation light emitted from the light source to the object by reflecting and scattering the irradiation light, and the reflection / scattering unit includes an integrating sphere. It is preferred that Further, there is provided transmitted light intensity detecting means for detecting the intensity of transmitted light transmitted through the object to be measured, and the calculating means includes a transmitted light intensity detecting means together with a detection result of the irradiation light intensity detecting means and a detection result of the reflected light intensity detecting means. The water content of the object to be measured may be calculated based on the detection result.In this case, a part of the light transmitted through the object to be measured may be selectively transmitted as transmitted light. May be provided to selectively transmit light to the transmitted light intensity detecting means.
[0013]
Further, in the water content measuring device according to the present invention, of the light guided to the irradiation light intensity detecting means, the reflected light intensity detecting means and the transmitted light intensity detecting means, light having a wavelength range of 1.8 μm or more is selectively transmitted. An optical filter may be provided, and this optical filter is preferably made of germanium. Optical separation for separating light guided to the irradiation light intensity detection means, the reflected light intensity detection means, and the transmitted light intensity detection means into light in a wavelength range of 1.8 μm or more and light in a wavelength range of less than 1.8 μm. The irradiation light intensity detecting means, the reflected light intensity detecting means, and the transmitted light intensity detecting means, wherein the light intensity in the wavelength range of 1.8 μm or more and the wavelength range of less than 1.8 μm are separated by the optical separation means. And the optical intensity may be separately detected, and the optical separating means is preferably a half mirror.
[0014]
The expression “selectively transmitting light in a wavelength range of 1.8 μm or more of light” regarding the “optical filter” described above transmits only light in a wavelength range of strictly 1.8 μm or more ( Not only the case where light in a wavelength region of less than 1.8 μm is not transmitted at all), but also a light having a large proportion of light in a wavelength region of 1.8 μm or more in the entirety is transmitted (light in a wavelength region of 1.8 μm or more). Is transmitted largely and light in other wavelength ranges is also slightly transmitted). Similarly, the expression “separating light into light in a wavelength range of 1.8 μm or more and light in a wavelength range of less than 1.8 μm” regarding the above “optical separation means” is based on a wavelength of 1.8 μm. The ratio of light occupied by light in the wavelength region of 1.8 μm or more in the whole is not limited to the case where the light is strictly separated into light in the wavelength region of 1.8 μm or more and light in the wavelength region of less than 1.8 μm. The proportion of large light (light mostly including light in the wavelength range of 1.8 μm or more and slightly including light in the wavelength range of less than 1.8 μm) and light in the wavelength range of less than 1.8 μm in the whole is large. This also includes the case where the light is separated into light (light that mostly includes light in a wavelength range of less than 1.8 μm and slightly includes light in a wavelength range of less than 1.8 μm). Needless to say, the expression “the light intensity in the wavelength range of 1.8 μm or more and the light intensity in the wavelength range of less than 1.8 μm are separately detected” has the same meaning.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
[First Embodiment]
First, a configuration of a water content measuring device according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2 show a cross-sectional configuration of the water content measuring device according to the present embodiment. FIG. 1 shows a state when reflected light intensity is detected, and FIG. 2 shows a state when irradiated light intensity is detected. I have.
[0017]
This water content measuring device is mounted on, for example, a copying machine or a printer, and is used to measure the water content Q of paper P as an object to be measured, as shown in FIGS. 1 and 2. A light source 1, an integrating sphere 2 (reflection / scattering means) for guiding the reflected light I radiated from the light source 1 to the paper P by reflecting and scattering the light, and reflected light reflected on the paper P when the reflected light intensity is detected. A detector 4 (reflected light intensity detecting means) for detecting the intensity of R, a reflecting plate 20 (reflecting means) for reflecting the irradiation light I at the time of detecting the irradiation light intensity, a condensing lens 5, and a filter 6 for wavelength separation. (Optical filter). The integrating sphere 2 is provided with openings 2KA, 2KB and 2KC, for example, laterally, below and above, respectively, and inside the integrating sphere 2, a baffle 7 as a barrier is provided.
[0018]
The light source 1 emits irradiation light I including infrared light, specifically, light (infrared light) in a wavelength range of 1.8 μm or more. The light source 1 is formed of, for example, a filament light bulb, and is disposed in the opening 2KA of the integrating sphere 2.
[0019]
The integrating sphere 2 is a substantially spherical vessel for irradiating the irradiation light I on the paper P isotropically by confining the irradiation light I and causing it to be reflected and scattered. The integrating sphere 2 has, for example, an inner surface (scattering surface 2M) having a fine concavo-convex structure (for example, a surface roughness of about several tens μm) in order to enhance the reflection and scattering of the irradiation light I. Has a configuration in which a high-infrared reflective scattering film 2S constituting a scattering surface 2M is provided on the inner surface of a metal sphere 2G. The scattering film 2S is, for example, a metal plating film (for example, gold, silver, copper, chromium, or nickel), or a coating film (for example, fluororesin, polyethylene or An inorganic pigment), a metal oxide vapor-deposited film (for example, magnesium oxide), or a metal oxide film (for example, alumite) in which the inner surface of the sphere 2G (for example, aluminum) is anodized. When the scattering film 2S is made of a metal other than gold, for example, a gold plating film for corrosion protection may be further provided on the scattering film 2S.
[0020]
The reflecting plate 20 reflects the irradiation light I emitted from the light source 1 toward the detector 4 as reflected light R0, and is made of, for example, a fluorine resin or a fluorine resin in which graphite is dispersed. The reflection plate 20 is arranged corresponding to the opening 2KB of the integrating sphere 2, and its reflectance is known.
[0021]
The detector 4 has a detection sensitivity in an infrared wavelength range, and is constituted by, for example, a pyroelectric element. The detector 4 is arranged, for example, corresponding to the opening 2KC of the integrating sphere 2, and is arranged in a straight line with the lens 5 and the filter 6. In particular, the detector 4 has a function of detecting the intensity of the reflected light R0 (that is, the intensity of the irradiation light I) as well as a function of detecting the intensity of the reflected light R (irradiation light intensity detection means). The intensity of the irradiation light I is indirectly detected through the light source. The term "indirect" as used herein means that the irradiation light I emitted from the light source 1 is not detected without being reflected by the reflection plate 20, but is detected after being reflected by the reflection plate 20. .
[0022]
The lens 5 condenses the reflected lights R, R0 and the irradiation light I and guides them to the filter 6, and is made of, for example, glass. The lens 5 is designed such that the detection viewing angle of the detector 4 is included in an exposed area of the paper P (an area exposed corresponding to the opening 2KB of the integrating sphere 2).
[0023]
The filter 6 selectively transmits the light (reflected light R1, R01) in the wavelength range of 1.8 μm or more out of the reflected light R, R0 and guides the light to the detector 4. For example, the filter 6 is mainly 1.8 μm. It is made of germanium (for example, a germanium plate) having infrared absorption characteristics in a wavelength range of less than. Note that the expression “selectively transmitting light in the wavelength range of 1.8 μm or more of the reflected lights R and R0” is strictly transmitted only in the wavelength range of 1.8 μm or more (1 Not only the case where light in a wavelength range of less than 0.8 μm is not transmitted at all), but also the light having a large proportion of light in a wavelength range of 1.8 μm or more in the entirety is transmitted (light in a wavelength range of 1.8 μm or more). This means that the light is transmitted most of the light and light in a wavelength range of less than 1.8 μm is also slightly transmitted. The same is true for the filters 61 and 62 described later.
[0024]
The reason for transmitting the reflected lights R1 and R01 in the filter 6 is as follows. That is, as the wavelength range of the infrared light having high water absorbability, there are generally known three wavelength ranges of around 1.4 μm, around 1.9 μm, and around 3.0 μm. If infrared light is used, it is possible to measure the water content Q of the paper P based on a change in the intensity of the infrared light due to an absorption phenomenon by water. In this case, in particular, when measuring the water content Q, it is preferable to use infrared light in a wavelength range near 1.9 μm or 3.0 μm among infrared light in three wavelength ranges. This is because the infrared light in the wavelength region near 1.4 μm has a lower water absorbability than the infrared light in the other two wavelength regions, and the detector 4 detects the change in the intensity of the infrared light due to the water absorption. Because it is difficult. In this case, the light source 1 and the detector 4 having excellent monochromaticity are required, which is not preferable in reducing the cost of the water content measuring device.
[0025]
The filter 6 is not limited to a germanium plate, for example. Instead of the germanium plate, another filter material having infrared absorption characteristics mainly in a wavelength region of less than 1.8 μm, specifically, a diffraction grating, a thin film interference filter Alternatively, it may be constituted by a band-pass filter or the like. However, these other filter materials are generally expensive, and in particular, when a diffraction grating with insufficient light use efficiency is used, a high-output type light source 1 and a high-sensitivity type detector 4 are required, and the apparatus is required. To increase the cost, it is preferable to use an inexpensive germanium plate in order to reduce the cost of the apparatus. If this germanium plate is used as the filter 6, the reflected light R1 and R01 can be transmitted stably using the infrared absorption characteristics based on the transition between the bands of the germanium element.
[0026]
The baffle 7 prevents the irradiation light I from being directly irradiated onto the paper P without being reflected and scattered by the integrating sphere 2, and reflects the irradiation light I toward the paper P. The two openings 2KA and 2KB are arranged at positions between the two openings 2KA and 2KB. Whether or not the baffle 7 is provided can be freely set.
[0027]
The paper P as an object to be measured is supported by a transport mechanism (not shown) such as a transport roller mounted on a copier or a printer together with a water content measuring device, and passes over the reflection plate 20. And are conveyed sequentially.
[0028]
Next, a detailed configuration of the water content measuring device will be described with reference to FIGS. FIG. 3 shows a block configuration of the water content measuring device shown in FIGS. 1 and 2.
[0029]
This water content measuring device includes a memory 8 for storing various information, a series of components including the light source 1 and the detector 4 shown in FIGS. 1 and 2, a controller 9 for controlling the entire device, and a controller 9 (arithmetic means). An amplifier 10 amplifies an output signal of the detector 4 and an analog / digital (A / D) converter 11 for converting the output signal from an analog signal to a digital signal.
[0030]
The memory 8 stores information necessary for the controller 9 to perform the arithmetic processing of the water content Q. For example, a register, a random access memory (RAM), a read only memory (ROM), or an electrically erasable programmable read only memory (EEPROM) is stored. A storage device such as an “Only Memory”. In the memory 8, for example, calculation data including calibration curve data C representing the correlation between the absorption / scattering ratio AD / SD and the water content Q, which will be described later, is stored in advance as constants.
[0031]
The controller 9 reads necessary calculation data from the memory 8 at any time and calculates the water content Q based on the detection result of the detector 4. For example, the controller 9 controls a CPU (Central Processing Unit). Device.
[0032]
The controller 9 is provided with a detector as necessary to prevent the calculation result of the water content Q from containing an error due to unnecessary infrared light (background radiation) generated from a heat source other than the light source 1, for example. 4 has a function of correcting the detection intensity. Specifically, for example, at predetermined calculation intervals, the controller 9 detects the detection result of the detector 4 in the case where the light source 1 is operating and the irradiation light I is emitted, and the irradiation result when the light source 1 is stopped. By comparing the detection result of the detector 4 when the light I is not irradiated, the difference between the two detection results (the intensity of the mixed light in which the reflected light R1 and the light caused by the background radiation are mixed) is obtained. And the intensity of the light caused by the background radiation), and then calculates the reflected light R generated on the paper P when the irradiation light I is emitted from the light source 1 to the detector 4. It is determined as a detection result (that is, the intensity of the reflected light R1), and the water content Q is corrected based on the calculated value.
[0033]
Next, the operation of the water content measuring device will be described with reference to FIGS.
[0034]
In this water content measuring device, the following optical principle is established between the light source 1 and the detector 4. That is, as shown in FIG. 1, when the irradiation light I is emitted from the light source 1 in a state where the paper P is transported on the reflection plate 20, the irradiation light I is reflected on the scattering surface 2M of the integrating sphere 2. The light is guided to the paper P through the opening 2KB by being scattered, and is radiated to the paper P isotropically. The term “isotropic” means that the intensity of the irradiation light I is substantially proportional to the cosine of the angle between the axis perpendicular to the paper P and the irradiation direction of the irradiation light I. Then, when the reflected light R is generated on the paper P, only the component of the reflected light R that travels in the arrangement direction of the lens 5, the filter 6, and the detector 4 is guided to the lens 5 through the opening 2KC. After being collected, the light is further wavelength-separated in the filter 6. As a result, of the reflected light R, light in the wavelength range of 1.8 μm or more (reflected light R1) passes through the filter 6 and is detected by the detector 4. On the other hand, as shown in FIG. 2, when irradiation light I is emitted from the light source 1 in a state where the paper P is transported from above the reflection plate 20 along the arrow Y, the irradiation light I After being reflected as the reflected light R0, the light is guided to the filter 6 via the lens 5, so that the wavelength separation function of the filter 6 is used as in the case of the reflected light R described above. Light in the wavelength range of 1.8 μm or more (reflected light R01) is detected by the detector 4.
[0035]
The process of detecting the reflected light R01 by the detector 4 and the process of calculating the water content Q based on the intensity of the reflected lights R1 and R01 may be performed, for example, every time the water content Q is measured. Alternatively, the measurement may be performed at predetermined measurement intervals (for example, every ten measurements). In the latter case, normally, the intensity of the reflected light R1 and the intensity of the previously detected reflected light R01 (or calculated based on the reflected light R01 using an arithmetic expression reflecting the deterioration state of the light source 1). And the water content Q is calculated based on the intensity.
[0036]
The controller 9 calculates the water content Q based on the detection result of the detector 4 according to the following operation procedure. That is, first, the reflectance RD is calculated based on the intensities of the reflected lights R1 and R01 detected by the detector 4. Subsequently, an absorption / scattering ratio AD / SD is calculated based on the reflectance RD. Finally, the calibration curve data C is read from the memory 8, and the water content Q corresponding to the absorption / scattering ratio AD / SD is specified based on the calibration curve data C. Thereby, the water content Q is calculated based on the detection result of the detector 4.
[0037]
Here, the principle of calculating the absorption / scattering ratio AD / SD by the controller 9 will be described. That is, for example, when the transmittance of the paper P is so small as to be negligible, the relationship of the following equation 1 is established among the reflectance RD, the absorption AD, and the scattering SD based on the Kubelka-Munk scattering model. Then, the relationship between the absorption ratio AD and the scattering ratio SD is expressed as a function of the reflectance RD. Therefore, if the above-mentioned relational expression is used, when the scattering ratio SD is known, the reflectance RD is actually measured, and based on the reflectance RD, the absorption / scattering ratio AD / SD (absorption ratio AD and scattering Ratio SD) can be calculated.
[0038]
(Equation 1)

[0039]
The water content measuring device according to the present embodiment includes the reflector 20 that reflects the irradiation light I toward the detector 4 as the reflected light R0, and the detector 4 detects the intensity of the reflected light R0 together with the intensity of the reflected light R. Since the detector also has a function, the detector 4 can detect the intensity of the reflected light R1, R01, and calculate the water content Q based on the detection result of the reflected light R1, R01. In this case, unlike the conventional water content measuring device that calculates the water content Q using the intensity of the irradiation light I as an invariable constant, for example, the intensity of the irradiation light I changes with time due to deterioration of the light source 1 or the like. When the intensity of the irradiation light I changes with time, the intensity of the irradiation light I is measured, and then the intensity of the irradiation light I (the intensity change of the reflection light R01) is added to the intensity of the reflection light R1 together with the intensity of the reflection light R1. The reflectance RD is calculated. Therefore, in the present embodiment, a factor that may cause an error in the measurement accuracy of the water content Q in terms of a change in the intensity of the irradiation light I is removed, and the error is eliminated. Can be measured.
[0040]
In particular, in the present embodiment, based on the point that the measurement accuracy of the water content Q of the paper P is improved, printing is performed according to the water content Q of the paper P in a copying machine, a printer, or the like equipped with the water content measurement device. By controlling the conditions, it is possible to improve the print quality.
[0041]
In addition, in the present embodiment, since the integrating sphere 2 that guides the irradiation light I emitted from the light source 1 to the paper P by reflecting and scattering the light is provided, the reflected light is scattered and scattered on the scattering surface 2M of the integrating sphere 2. Irradiation light I is applied to the paper P isotropically. In this case, unlike the case where the integrating sphere 2 is not provided and the irradiation light I is not radiated to the paper P isotropically, the intensity of the reflected light R has an angular distribution based on a substantially perfect scattering surface. Since the intensity of the reflected light R is almost proportional to the cosine of the angle between the axis perpendicular to P and the traveling direction of the reflected light R, the absolute reflectance can be calculated as the reflectance RD of the paper P. become. Therefore, in the present embodiment, since the error due to the angular distribution of the intensity of the reflected light R is reduced, it is possible to contribute to the improvement of the measurement accuracy of the water content Q from this viewpoint. In this case, in particular, since the irradiation light I emitted from the light source 1 is confined inside the integrating sphere 2, the irradiation efficiency of the irradiation light I applied to the paper P is improved, so that the detection intensity of the detector 4 is reduced. It can be sufficiently secured.
[0042]
Further, in the present embodiment, since the filter 6 for separating the wavelength of the reflected light R and R0 is provided, the water content Q of the reflected light R and R0 is Light (reflected light R1, R01) in a wavelength range of 1.8 μm or more useful for measurement selectively passes through the filter 6 and reaches the detector 4. Therefore, the detector 4 can stably and easily detect the intensity of the reflected lights R1 and R01.
[0043]
Further, in the present embodiment, since the glass lens 5 is used, the reflected light R is utilized by utilizing the infrared absorption characteristic of glass, that is, the characteristic of absorbing infrared light in a wavelength region of 4.0 μm or more. , R0 pass through the lens 5, the infrared light in the wavelength range of 4.0 μm or more of the reflected light R, R0 is absorbed by the lens 5. Therefore, the reflected light R and R0 excluding light in an unnecessary wavelength range that induces a calculation error due to heat radiation are guided to the filter 6, and the water content Q is calculated due to the presence of the unnecessary infrared light. An error can be prevented from being included in the result.
[0044]
Further, in the present embodiment, light (reflection) in a wavelength range within a relatively narrow range of substantially 1.8 μm or more and less than 4.0 μm, based on the wavelength separation effect of the filter 6 and the infrared absorption characteristics of the lens 5 described above. Since the water content Q is calculated using the light R1, R01), the infrared light in the two wavelength ranges described in the above section of the “prior art” (the wavelength range of 1 μm or more having high water absorbability). Compared with a conventional water content measuring apparatus using light and light having a low water absorbency in a wavelength range of less than 1 μm, the measurement accuracy of the water content Q is further improved. This is because in the conventional case using light in a relatively wide range of wavelengths of 1 μm or more, the entire wavelength range is too large for the wavelength range of light absorbed by water. The reflected light energy in the wavelength range that is water-absorbable with respect to the light energy becomes extremely small, making it difficult to detect the change in the reflected light intensity. In the case of the present embodiment using light in the wavelength range within, compared with the conventional case, the reflected light energy in the water-absorbable wavelength range is larger than the reflected light energy in the entire wavelength range. This is because it becomes easy to detect the change in the reflected light intensity.
[0045]
[Second embodiment]
Next, a second embodiment of the present invention will be described.
[0046]
FIG. 4 shows a schematic configuration of the water content measuring device according to the present embodiment. In FIG. 4, the same components as those described in the first embodiment are denoted by the same reference numerals.
[0047]
This water content measuring device calculates the water content Q based on the detection result of the reflected light R and the detection result of the irradiation light I, as in the first embodiment. For example, as shown in FIG. As described above, the reflecting plate 20 is not provided, and the opening 2KD is provided on the side of the integrating sphere 2 so as to face the opening 2KA, and a lens for detecting the intensity of irradiation light corresponding to the opening 2KD. 51, a filter 61 and a detector 41 (irradiation light intensity detecting means) are arranged, another integrating sphere 21 is connected to the integrating sphere 2 through the opening 2KA, and the light source 1 is arranged in the integrating sphere 21. Except for this point, it has a configuration similar to that of the first embodiment (see FIGS. 1 to 3).
[0048]
The integrating sphere 21 reflects and scatters the irradiation light I to guide it to the integrating sphere 2 through the opening 2KA. For example, the integrating sphere 21 has the same configuration as the integrating sphere 2, that is, a scattering surface is provided on the inner surface of the sphere 21G. It has a configuration in which a scattering film 21S constituting 21M is provided. The dimension (for example, the inner diameter) of the integrating sphere 21 is smaller than, for example, the dimension of the integrating sphere 2. A baffle 71 is disposed inside the integrating sphere 21 at a position between the light source 1 and the opening 2KA.
[0049]
The lens 51 condenses the irradiation light I, and has, for example, the same configuration as the lens 5. Whether or not the lens 51 is provided can be freely set. The filter 61 separates the irradiation light I into wavelengths and has, for example, the same configuration as the filter 6. The detector 41 detects the intensity of the irradiation light I, that is, directly detects the intensity of the irradiation light I emitted from the light source 1 through the opening 2KD. The term "direct" here is different from the first embodiment in which the irradiation light I emitted from the light source 1 is detected after being reflected by the reflection plate 20 as the reflection light R0. This means that light other than the reflected light R0 reflected at 20 is detected (the irradiation light I is detected as it is). The detector 41 has, for example, a configuration similar to that of the detector 4.
[0050]
In this moisture content measuring device, when the irradiation light I is emitted from the light source 1 and the reflected light R is generated in a state where the paper P is transported, as shown in FIG. 4, the description will be given in the first embodiment. Based on the optical principle described above, the light in the wavelength range of 1.8 μm or more (reflected light R1) of the reflected light R is detected by the detector 4 by utilizing the wavelength separation action of the filter 6, and the irradiation light I Is guided to the filter 61 via the lens 51 through the opening 2KD, so that the wavelength of 1.8 μm or more of the irradiation light I is utilized by utilizing the wavelength separation effect of the filter 61 in the same manner as the reflected light R described above. Light in the region (irradiation light I1) is detected by the detector 41. Accordingly, the controller 9 shown in FIG. 3 calculates the water content Q based on the detection results of the detectors 4 and 41 through the same calculation procedure as that of the first embodiment.
[0051]
In the water content measuring device according to the present embodiment, in addition to the detector 4 for detecting the intensity of the reflected light R1, a detector 41 for detecting the intensity of the irradiation light I1 is provided. In addition to detecting the intensity, the detector 41 detects the intensity of the irradiation light I1 and the water content Q can be calculated based on the detection result of the irradiation light I1 together with the detection result of the reflected light R1. Therefore, the water content Q of the paper P can be measured with high accuracy by the same operation as in the first embodiment.
[0052]
In particular, in the present embodiment, since the light source 1 is arranged in the integrating sphere 21 connected to the integrating sphere 2, the integrating sphere 2 is not connected to the integrating sphere 2 and the light source Unlike the case where 1 is provided, most of the irradiation light I enters the detector 41 after being reflected and scattered by the integrating spheres 2 and 21. Therefore, it is possible to reduce an error caused by the angular distribution of the intensity of the irradiation light I, and from this viewpoint, it is possible to contribute to improvement of the measurement accuracy of the water content Q.
[0053]
In addition, other detailed actions, operations, effects, and the like regarding the water content measuring device according to the present embodiment are the same as those in the first embodiment.
[0054]
[Third Embodiment]
Next, a third embodiment of the present invention will be described.
[0055]
5 and 6 show a schematic configuration of the water content measuring apparatus according to the present embodiment. FIG. 5 shows a state at the time of detecting reflected light intensity and transmitted light intensity, and FIG. The state of is shown. In FIGS. 5 and 6, the same reference numerals are given to the same components as those described in the first embodiment.
[0056]
This water content measuring device is different from the first embodiment in which the water content Q is calculated based on the detection result of the reflected light R and the detection result of the irradiation light I, and the detection result of the reflected light R and the irradiation The water content Q is calculated based on the detection result of the transmitted light T together with the detection result of the light I. The water content Q of the non-transparent paper P as well as the transparent (for example, thin or low-density) paper The water content Q of P is also used for measuring. This water content measuring device, for example, as shown in FIGS. 5 and 6, is not provided with the reflecting plate 20, is disposed below the integrating sphere 2, and is provided with an opening 22KA provided above and laterally. An integrating sphere 22 having an opening 22KB provided therein, and a transmitted light intensity detecting lens 52, a filter 62, and a detector 42 (transmitted light intensity detecting means) arranged corresponding to the opening 22KB are newly provided. Except for this point, it has the same configuration as that of the water content measuring device of the first embodiment (see FIGS. 1 to 3).
[0057]
The integrating sphere 22 reflects the illuminating light I guided through the integrating sphere 2 together with the transmitted light T transmitted through the paper P, and scatters the illuminating light I to guide the illuminating light I to the detector 42 through the opening 22KB. It has a configuration similar to that of the sphere 2, that is, a configuration in which a scattering film 22S forming a scattering surface 22M is provided on the inner surface of the sphere 22G. The dimensions (for example, the inner diameter) of the integrating sphere 22 are substantially the same as, for example, the dimensions of the integrating sphere 2.
[0058]
The lens 52 collects the transmitted light T, and has, for example, the same configuration as the lens 5. The filter 62 separates the irradiation light I into wavelengths together with the transmitted light T, and has, for example, the same configuration as the filter 6. The detector 42 detects the intensity of the irradiation light I together with the intensity of the transmitted light T, and has, for example, a configuration similar to that of the detector 4.
[0059]
In this water content measuring device, as shown in FIG. 5, in a state where the paper P is transported to a position between the integrating spheres 2 and 22, when the irradiation light I is irradiated from the light source 1, the reflected light is reflected on the paper P. R and transmitted light T occur. Since the reflected light R is guided to the filter 6 and wavelength-separated based on the optical principle described in the first embodiment, the light in the wavelength range of 1.8 μm or more of the reflected light R is included. (Reflected light R1) is detected by the detector 4. The transmitted light T is guided to the integrating sphere 22 through the opening 22KA, is reflected and scattered on the scattering surface 22M of the integrating sphere 22, and is guided to the filter 62 via the lens 52 through the opening 22KB. Since the wavelength is separated by the filter 62, the light in the wavelength range of 1.8 μm or more (the transmitted light T1) of the transmitted light T is detected by the detector 42 in the same manner as the reflected light R. On the other hand, as shown in FIG. 6, when the irradiation light I is emitted from the light source 1 in a state where the paper P is transported from the position between the integrating spheres 2 and 22, the irradiation light I passes through the integrating sphere 2. As a result, the light (irradiation light I1) in the wavelength range of 1.8 μm or more of the irradiation light I is detected by the detector 42 in the same manner as the above-described transmitted light T.
[0060]
In this case, the controller 9 shown in FIG. 3 calculates the water content Q based on the detection results of the detectors 4 and 42 according to the following operation procedure. That is, first, the reflectance RD is calculated based on the intensity of the irradiation light I1 detected by the detector 42 and the intensity of the reflected light R1 detected by the detector 4. Subsequently, the transmittance TD is calculated based on the intensity of the irradiation light I and the intensity of the transmitted light T1 detected by the detector 42. Subsequently, an absorption / scattering ratio AD / SD is calculated based on the reflectance RD and the transmittance TD. Finally, the calibration curve data C is read from the memory 8, and the water content Q corresponding to the absorption / scattering ratio AD / SD is specified based on the calibration curve data C. Thus, the water content Q is calculated based on the detection results of the detectors 4 and 42.
[0061]
Here, the calculation principle of the absorption / scattering ratio AD / SD by the controller 9 in consideration of the transmittance TD will be described. That is, if the equation 1 based on the above-described Kubelka-Munk scattering model is applied, the following equation 2 is established among the reflectance RD, the absorption rate AD, the scattering rate SD, and the transmittance TD. In Formula 2, R∞ is a reflectance when the thickness of the paper P is infinite, and Rg is a unique reflectance (known) corresponding to the integrating sphere 22. Therefore, if Equation 2 is used, the reflectance R∞ is calculated based on the reflectance RD and the transmittance TD, and the absorption / scattering ratio AD / SD is calculated based on the reflectance R∞. It becomes possible. Note that, in Equation 2, the reflectance RD is simplified to be shown as “R”, and the transmittance TD is simplified to be shown as “T”.
[0062]
[Equation 2]

[0063]
The water content measuring apparatus according to the present embodiment includes the detector 42 for detecting the intensity of the transmitted light T1 and the intensity of the irradiation light I1 in addition to the detector 4 for detecting the intensity of the reflected light R1. 4, the intensity of the reflected light R1 is detected, and the intensity of the transmitted light T1 and the intensity of the irradiation light I1 are detected by the detector 42. The detection result of the transmitted light T1 and the detection result of the irradiation light I are detected together with the detection result of the reflected light R1. It is possible to calculate the water content Q based on the In this case, when measuring the water content Q of the paper P such that the intensity of the transmitted light T1 is not negligible, only the intensity of the reflected light R1 and the intensity of the irradiation light I1 are taken into account without considering the intensity of the transmitted light T1. , The dependency of the reflectance RD on the thickness of the paper P is corrected by an amount that takes into account the intensity of the transmitted light T1. That is, the reflectance RD is converted into a reflectance R∞ obtained when the thickness of the paper P is sufficiently large by taking into account the transmittance TD and using the above-described Expression 2, and then the reflectance R∞ is calculated. Since the water content Q is calculated based on the influence of the thickness of the paper P, the calculation accuracy of the water content Q is improved. Therefore, in the present embodiment, in addition to the water content Q of the non-transparent paper P, the water content Q of the transparent paper P that is so large that the influence of the transmitted light T cannot be ignored can be measured with high accuracy. it can.
[0064]
In particular, in the present embodiment, since the integrating sphere 22 for reflecting and scattering the transmitted light T is provided, the trapping rate of the transmitted light T is increased as compared with the case where the integrating sphere 22 is not provided, and the transmitted light T Errors due to the angular distribution of the intensity are reduced. Therefore, also from this viewpoint, it is possible to contribute to improvement of the measurement accuracy of the water content Q.
[0065]
In addition, other detailed actions, operations, effects, and the like regarding the water content measuring device according to the present embodiment are the same as those in the first embodiment.
[0066]
[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described.
[0067]
FIG. 7 shows a schematic configuration of the water content measuring device according to the present embodiment. In FIG. 7, the same components as those described in the third embodiment are denoted by the same reference numerals.
[0068]
This water content measuring device calculates the water content Q based on the detection result of the transmitted light T together with the detection result of the reflected light R and the detection result of the irradiation light I, similarly to the third embodiment. For example, as shown in FIG. 7, except that a semi-transmissive reflection plate 32 (selective transmission means) is newly provided between the integrating spheres 2 and 22, the water content measurement of the third embodiment is performed. It has a configuration similar to that of the device (see FIGS. 5, 6, and 3).
[0069]
The semi-transmissive reflection plate 32 selectively transmits a part of the light transmitted through the paper P as transmitted light T to guide the light to the detector 42 via the integrating sphere 22 and transmit the paper P. The reflected light is guided to the detector 4 via the integrating sphere 2 by reflecting the remaining light, and is made of, for example, polyethylene or fluoroplastic. The surface of the transflective plate 32 is roughened, and it is preferable that light is scattered and reflected on the surface. Alternatively, the transflective plate 32 is made of porous plastic. It is preferable that light is scattered and reflected inside. The scattering ratio, the reflectance, and the thickness of the transflective plate 32 are known.
[0070]
In the moisture content measuring device, when the light P is irradiated from the light source 1 in a state where the paper P is transported on the semi-transmissive reflection plate 32, the reflected light R and the transmitted light T are generated in the paper P. The transmitted light T is a part of the light transmitted through the paper P, that is, the light that is selectively transmitted through the semi-transmissive reflection plate 32 and guided to the integrating sphere 22. The reflected light R is the remaining light transmitted through the paper P, that is, the light reflected by the semi-transmissive reflection plate 32 and guided again to the integrating sphere 2 via the paper P, and the reflected light R Is a mixed light with the light reflected at. Since the reflected light R is guided to the filter 6 and wavelength-separated based on the optical principle described in the first embodiment, the light in the wavelength range of 1.8 μm or more of the reflected light R is included. (Reflected light R1) is detected by the detector 4. On the other hand, the transmitted light T is guided to the filter 62 and wavelength-separated based on the optical principle described in the third embodiment, so that the transmitted light T in the wavelength range of 1.8 μm or more of the transmitted light T Light (transmitted light T1) is detected by the detector 42. Although not shown, in this moisture content measuring device, in a state where the paper P is conveyed from above the semi-transmissive reflection plate 32, in the same manner as in the third embodiment described with reference to FIG. The light (irradiation light I1) in the wavelength range of 1.8 μm or more of the irradiation light I is detected by the detector 42. Accordingly, the controller 9 shown in FIG. 3 calculates the water content Q based on the detection results of the detectors 4 and 42 through the same calculation procedure as that of the third embodiment.
[0071]
The water content measuring device according to the present embodiment includes the semi-transmissive reflection plate 32 that selectively transmits part of light transmitted through the paper P as transmitted light T. In addition to detecting the intensity of the transmitted light T1 and the intensity of the irradiation light I, the detector 4 detects the intensity of the reflected light R1 and based on the detection result of the reflected light R1 and the detection result of the transmitted light T1 and the intensity of the irradiation light I. It is possible to calculate the water content Q. Therefore, also in this case, the absorption / scattering ratio AD / SD is calculated in consideration of the intensity of the transmitted light T, and the water content Q is calculated based on the absorption / scattering ratio AD / SD. By the same operation as in the third embodiment, the water content Q of the paper P can be measured with high accuracy.
[0072]
In addition, other detailed actions, operations, effects, and the like regarding the water content measuring device according to the present embodiment are the same as those in the third embodiment.
[0073]
[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described.
[0074]
8 and 9 show a schematic configuration of the water content measuring device according to the present embodiment, FIG. 8 shows a state before the paper P is conveyed, and FIG. 9 shows a state after the paper P is conveyed. ing. In FIGS. 8 and 9, the same reference numerals are given to the same components as those described in the third embodiment.
[0075]
This water content measuring device detects the intensity of the reflected light R and the intensity of the transmitted light T with respect to the front and back surfaces of the paper P, and detects the detection result of the reflected light R and the irradiation light I in the same manner as in the third embodiment. The water content Q is calculated based on the detection result of the transmitted light T together with the detection result. This water content measuring device is composed of, for example, the water content measuring device described in the third embodiment (see FIGS. 5, 6, and 3) as shown in FIGS. 8 and 9. It has a configuration in which two water content measurement units 100A and 100B are provided, and these two water content measurement units 100A and 100B are arranged along the traveling direction of the paper P (arrow Y) in a state where they are turned upside down. I have.
[0076]
The paper P has a pair of opposing surfaces PX (front surface) and PY (back surface). For example, the paper P has a printing screen G on the back surface PY. The printing screen G is, for example, a character or an image formed by using a toner or the like by a copier, a printer, or the like. The paper P is transported from a position TA corresponding to the water content measuring unit 100A to a position TB corresponding to the water content measuring unit 100B by using a transport mechanism (not shown).
[0077]
When the paper P is inserted into the water content measuring device such that the back surface PY having the printing screen G faces downward, at a position TA, the detector 4 of the water content measuring unit 100A causes the reflected light on the back surface PY of the paper P to be reflected. The detector 42 has a function of detecting the intensity of the R light, and the detector 42 has a function of detecting the intensity of the transmitted light T located on the surface PX side of the paper P. On the other hand, at the position TB, the detector 4 of the water content measuring unit 100B has a function of detecting the intensity of the reflected light R with respect to the front surface PX of the paper P, and the detector 42 is located on the back surface PY side of the paper P and transmits the transmitted light. It has the function of detecting the intensity of T.
[0078]
In this moisture content measuring device, first, as shown in FIG. 8, when the irradiation light I is emitted from the light source 1 of the moisture content measuring unit 100A in a state where the paper P is transported to the position TA, the paper P Since the reflected light R generated on the back surface PY is guided to the filter 6 and wavelength-separated, light (reflected light R1) in the wavelength range of 1.8 μm or more of the reflected light R is detected by the detector 4 and Since the transmitted light T transmitted through the paper P is guided to the filter 62 and wavelength-separated, the light in the wavelength range of 1.8 μm or more (the transmitted light T1) of the transmitted light T is detected by the detector 42. . Subsequently, as shown in FIG. 9, in a state where the paper P is transported from the position TA to the position TB, when irradiation light is emitted from the light source 1 of the water content measuring unit 100B, the light is generated on the surface PX of the paper P. Since the reflected light R is guided to the filter 6 and wavelength-separated, the light (reflected light R1) in the wavelength range of 1.8 μm or more of the reflected light R is detected by the detector 4 and the paper P is removed. The transmitted transmitted light T is guided to the filter 62 and wavelength-separated, so that the light in the wavelength range of 1.8 μm or more (the transmitted light T1) of the transmitted light T is detected by the detector 42. Although not shown, in this water content measuring device, in a state where the paper P is conveyed from the position TA, as in the case described in the third embodiment with reference to FIG. In the detector 42 of the unit 100A, the light (irradiation light I1) in the wavelength range of 1.8 μm or more of the irradiation light I is detected, and the water content measurement unit is similarly similarly in a state where the paper is conveyed from the position TB. The irradiation light I1 is detected by the detector 42 of 100B.
[0079]
In this case, for example, the controller 9 shown in FIG. 3 may control the data detected by the water content measuring unit 100A, that is, the intensity of the reflected light R1, the intensity of the transmitted light T1, and the intensity of the reflected light R1 in consideration of the reflection characteristics of the back surface PY of the paper P. Based on the intensity of the irradiation light I and the data detected by the water content measuring unit 100B, that is, the intensity of the reflected light R1, the intensity of the transmitted light T1, and the intensity of the irradiation light I in consideration of the reflection characteristics of the surface PX of the paper P. After calculating the absorption / scattering ratio AD / SD, the water content Q is specified using the calibration curve data C based on the absorption / scattering ratio AD / SD.
[0080]
In the water content measuring device according to the present embodiment, the water content measuring unit 100A that detects the intensity of the reflected light R1 in consideration of the reflection characteristics of the back surface PY (print screen G) of the paper P, and the reflection related to the front surface PX of the paper P Since the apparatus is provided with the water content measuring unit 100B that detects the intensity of the reflected light R1 in consideration of the characteristics, the water content Q of the paper P having the printing surface G on the back surface PY is measured with high accuracy for the following reason. be able to.
[0081]
In other words, in consideration of the recent usage of copiers and printers, not only unprinted paper but also printed paper is often used. This is for the purpose of reusing the printed paper without discarding it and reprinting it on an unprinted screen (the side opposite to the printed screen). However, if toner for image formation or the like is present on one side of the paper, the scattering or absorption of the paper may change due to the presence of the toner or the like, and it becomes difficult to measure the water content with high accuracy.
[0082]
In this regard, in the present embodiment, as described above, in the present embodiment, the water content measuring unit 100A detects the intensity of the reflected light R1 in consideration of the reflection characteristics of the back surface PY (printed screen G) of the paper P, and also detects the water content. Since the measuring unit 100B detects the intensity of the reflected light R1 in consideration of the reflection characteristics of the surface PX of the paper P and calculates the water content Q including the intensity of the two reflected lights R1, the paper content is simply calculated. Unlike the case where the water content Q is calculated with respect to only one surface (PX or PY) of P, an optical error caused by a difference in light scattering rate or absorption rate caused by the presence of the printing screen G is corrected, The calculation accuracy of the water content Q is improved. Therefore, in the present embodiment, the water content Q of the paper P having the printing screen G on the back surface PY can be measured with high accuracy.
[0083]
In the above description, the water content measuring device of the present embodiment is used to measure the water content Q of the paper P having the printing screen G on the back surface PY, but the present invention is not necessarily limited to this. For example, the water content measuring device of the present embodiment may be used to measure the water content Q of the paper P (unused paper) having no printing screen G on any of the surfaces PX and PY. . Also in this case, the water content Q can be measured with high accuracy in consideration of the difference between the reflection characteristics of each surface PX and PY of the paper P.
[0084]
The functions, operations, effects, and modifications of the water content measuring device according to the present embodiment other than those described above are the same as those of the third embodiment, and thus description thereof will be omitted.
[0085]
[Sixth Embodiment]
Next, a sixth embodiment of the present invention will be described.
[0086]
10 and 11 show a schematic configuration of the water content measuring device according to the present embodiment. FIG. 10 shows a state before the paper P is inverted, and FIG. 11 shows a state after the paper P is inverted. ing. In FIGS. 10 and 11, the same reference numerals are given to the same components as those described in the third embodiment.
[0087]
This water content measuring device detects the intensity of the reflected light R and the intensity of the transmitted light T on the front and back surfaces of the paper P in the same manner as in the fifth embodiment, and detects the detection result of the reflected light R and the irradiation light I. The water content Q is calculated based on the detection result of the transmitted light T together with the detection result. For example, as shown in FIGS. 10 and 11, a reversing mechanism 34 for reversing the front and back of the paper P is newly provided. Except for this point, it has the same configuration as the water content measuring device of the third embodiment (see FIGS. 5, 6 and 3). The reversing mechanism 34 includes, for example, a transport roller for transporting the paper P, a reversing roller for reversing the paper P, and the like.
[0088]
In this water content measuring device, as shown in FIG. 10, when the irradiation light I is emitted from the light source 1 in a state where the paper P is transported so that the back surface PY having the printing screen G faces upward, Based on the optical principle described in the third embodiment, the reflected light R generated on the back surface PY of the paper P is guided to the filter 6 and wavelength-separated, so that 1.8 μm or more of the reflected light R is used. (Reflected light R1) is detected by the detector 4 and the transmitted light T transmitted through the paper P is guided to the filter 62 and wavelength-separated, so that 1.8 μm of the transmitted light T Light in the above wavelength range (transmitted light T1) is detected by the detector 42. Subsequently, as shown in FIG. 11, when the irradiation light I is emitted from the light source 1 in a state where the paper P is turned upside down by the reversing mechanism 34 and the back surface PY having the printing screen G faces downward, the paper P Since the reflected light R generated on the surface PX of P is guided to the filter 6 and wavelength-separated, light (reflected light R1) in the wavelength range of 1.8 μm or more of the reflected light R is detected by the detector 4. At the same time, the transmitted light T transmitted through the paper P is guided to the filter 62 and wavelength-separated, so that the light in the wavelength range of 1.8 μm or more (transmitted light T1) of the transmitted light T is detected by the detector 42. Is done. Although not shown, in this moisture content measuring apparatus, in the state before the paper P is conveyed, as in the case of the third embodiment described with reference to FIG. Light (irradiation light I1) in a wavelength range of 1.8 μm or more is detected by the detector 42.
[0089]
In this case, the controller 9 shown in FIG. 3, for example, detects the data detected by the detectors 4 and 42 before the inversion of the paper P, that is, the intensity and transmission of the reflected light R1 in consideration of the reflection characteristics of the back surface PY of the paper P. The intensity of the light T1 and the intensity of the irradiation light I, and the data detected after reversing the paper P, that is, the intensity of the reflected light R1, the intensity of the transmitted light T1, and the intensity of the irradiation light I in consideration of the reflection characteristics of the surface PX of the paper P. After calculating the absorption / scattering ratio AD / SD based on the above, the water content Q is specified using the calibration curve data C based on the absorption / scattering ratio AD / SD.
[0090]
Since the water content measuring device according to the present embodiment includes the reversing mechanism 34 for reversing the front and back of the paper P, the reversing mechanism 34 is used to reflect the reflection characteristics of the paper P with respect to the back PY. It is possible to detect the intensity of the light R1 and the intensity of the reflected light R1 in consideration of the reflection characteristics related to the surface PX, and calculate the water content Q including the intensity of the two reflected lights R1. Therefore, the operation accuracy of the water content Q is improved by the same operation as in the fifth embodiment, so that the water content Q of the paper P having the imprint G on the back surface PY can be measured with high accuracy.
[0091]
In particular, in the present embodiment, by using the reversing mechanism of the paper P by the reversing mechanism 34, as described in the fifth embodiment, substantially two water content measuring devices (the water content measuring unit 100A) are used. , 100B) can be used to calculate the water content Q using only one water content measuring device. Therefore, the size and cost of the device can be reduced as compared with the fifth embodiment.
[0092]
Note that other effects and modifications of the water content measuring device according to the present embodiment are the same as those of the third embodiment, and thus description thereof will be omitted.
[0093]
As described above, several water content measuring devices have been described as the first to sixth embodiments. However, the configuration of each water content measuring device can be freely changed as long as the accuracy of measuring the water content Q can be improved. It is possible.
[0094]
Specifically, in each of the above-described embodiments, the light source 1 that emits the irradiation light I including the infrared light in the wavelength range of 1.8 μm or more is used, but the light source 1 is not necessarily limited to this. Instead, for example, a device that irradiates only the infrared light in the wavelength region of 1.8 μm or more as the irradiation light I may be used. Examples of this type of light source 1 include an LED (Light Emitting Diode) and an LD (Laser Diode) that can emit only infrared light in a wavelength range near 1.9 μm. In this case, the same effects as those of the above embodiments can be obtained.
[0095]
Further, in the first embodiment (see FIGS. 1 and 2), the light (reflected light R1) in the wavelength range of 1.8 μm or more of the reflected light R and the 1.8 μm or more of the reflected light R0 are used. Although only the detector 4 for detecting the light (reflected light R01) in the wavelength range is provided and the water content Q is calculated based on the detection result of the detector 4, the present invention is not necessarily limited to this. As shown in FIGS. 12 and 13, in addition to the detector 4, a detector 43 for detecting light (reflected light R2, R02) in a wavelength range of less than 1.8 μm is provided and guided to these detectors 4, 43. Optical separation that separates the light (reflected light R, R0) into light in the wavelength range of 1.8 μm or more (reflected light R1, R01) and light in the wavelength range less than 1.8 μm (reflected light R2, R02). Means, detector 4, The water content Q may be calculated on the basis of both the detection results. Note that the expression “separating the reflected light R, R0 into light in a wavelength range of 1.8 μm or more and light in a wavelength range of less than 1.8 μm” is based on the wavelength of 1.8 μm as a reference (boundary). It is not limited to the case where the light in the wavelength region of 1.8 μm or more is strictly separated from the light in the wavelength region of less than 1.8 μm. Light that largely includes light in the wavelength range of 0.8 μm or more and slightly includes light in the wavelength range of less than 1.8 μm) and light that largely occupies light in the wavelength range of less than 1.8 μm (1. This largely includes light in a wavelength range of less than 8 μm, and slightly includes light in a wavelength range of less than 1.8 μm). The same is true for the irradiation light I (I1, I2) and the transmitted light T (T1, T2) described later. The detector 43 is composed of, for example, a silicon photodiode, a germanium photodiode, an indium gallium arsenide alloy photodiode, or a thermoelectric element. Further, the optical separating means is, for example, one in which the filter 6 is tilted and used as a half mirror. If necessary, a spectral limiting means such as a thin-film interference filter, a band-pass filter, or a diffraction grating may be used in combination with the detector 43, for example.
[0096]
In this moisture content measuring device, when the irradiation light I is emitted from the light source 1, the reflected light R is guided to the filter 6 to be wavelength-separated, as shown in FIG. Light (reflected light R1) in a wavelength range of 1.8 μm or more with high absorptivity is detected by the detector 4, and light (reflected light R2) in a wavelength range of 1.8 μm or less with low water absorptivity is detected by the detector 43. As well as being detected, as shown in FIG. 13, the reflected light R0 is guided to the filter 6 to be wavelength-separated in the same manner as the reflected light R, and of the reflected light R0, light (1.8 μm or more in the wavelength range) The reflected light R01) is detected by the detector 4, and the light (reflected light R02) in the wavelength range of less than 1.8 μm is detected by the detector 43. For example, depending on the spectral sensitivity characteristics of the detector 43, light in a wavelength range of 1.8 μm or more can be detected by the detector 43. In this case, the detector 43 is detected based on the detection results of the detectors 4 and 43. Is calculated by calculating the contribution of the intensity of light in the wavelength region of 1.8 μm or more to the detection value of the light in the wavelength region of less than 1.8 μm. The intensity is calculated.
[0097]
In this case, the water content of the paper P can be calculated based on the following calculation principle even when the scattering rate SD is not known. That is, the relational expression based on the above-described Kubelka-Munk scattering model is expressed as f (RD1) = AD1 / SD1 for light (reflected light R1, R01) in a wavelength range of 1.8 μm or more, while 1.8 μm It is assumed that f (RD2) = AD2 / SD2 with respect to light (reflected light R2, R02) in a wavelength range of less than. These RD2, AD2 and SD2 correspond to the reflectance, absorption and scattering of the paper P itself (excluding water), respectively. In this case, if the scattering rates are equal for both the reflected lights R1 and R2 (SD1 = SD2) and the absorption rate AD2 is known, based on the relationship f (RD1) / f (RD2) = AD1 / AD2. After calculating the absorption ratio AD1 / AD2, the water content Q of the paper P can be specified based on the absorption ratio AD1 / AD2. In this case, the influence of the fluctuation of the scattering rate SD is excluded based on the difference between the intensity of the reflected light R1, R01 having high water absorbability and the intensity of the reflected light R2, R02 having low water absorbability. Therefore, the calculation accuracy of the absorption ratio AD1 / AD2 is improved. Therefore, the water content Q of the paper P can be measured with extremely high accuracy. The other features of the water content measuring device shown in FIGS. 12 and 13 are the same as those of the water content measuring device shown in FIGS. 1 and 2. For reference, for example, when measuring the water content Q of pulp or the like having a constant material instead of paper P, the above-described absorption rate AD2 is constant. It is also possible to directly associate with.
[0098]
In particular, with respect to the water content measuring device shown in FIGS. 12 and 13, as described above, when the light source 1 that irradiates only the infrared light in the wavelength range of 1.8 μm or more as the irradiation light I is used, for example, Apart from this light source 1, another light source that irradiates only infrared light in a wavelength range of less than 1.8 μm as irradiation light I may be used. As the “other light source”, for example, an LD (Laser Diode) capable of selectively irradiating only infrared light in a wavelength range of less than 1.8 μm is exemplified. In this case, the same effect can be obtained.
[0099]
Note that the modifications shown in FIGS. 12 and 13 are not limited to the first embodiment, and can be applied to the other second to sixth embodiments.
[0100]
Specifically, when applied to the second embodiment, as shown in FIG. 14, the filter 61 is tilted and used as a half mirror, and the detector 44 is newly added in addition to the detector 41. With this arrangement, the light in the wavelength range of 1.8 μm or more (irradiation light I1) of the irradiation light I is detected by the detector 41, and the light in the wavelength range of less than 1.8 μm (irradiation light I2) is detected. Since the water content Q is detected by the detector 44, the water content Q of the paper P can be measured with extremely high accuracy by the same operation as that shown in FIGS.
[0101]
When the third embodiment is applied, as shown in FIGS. 15 and 16, the filter 62 is tilted and used as a half mirror, and a detector 45 is newly added in addition to the detector 42. If provided, as shown in FIG. 15, when the transmitted light T is detected, of the transmitted light T, light in the wavelength range of 1.8 μm or more (transmitted light T1) is detected by the detector 42, and Light in a wavelength range of less than 1.8 μm (transmitted light T2) is detected by the detector 45, and when the irradiation light I is detected, as shown in FIG. Light in the wavelength range (irradiation light I1) is detected by the detector 42, and light (irradiation light I2) in the wavelength range less than 1.8 μm is detected by the detector 45. Therefore, by the same operation as that of the reflected lights R1 and R2 described with reference to FIGS. 12 and 13, based on the intensity between the transmitted lights T1 and T2 and the intensity between the irradiation lights I1 and I2, the absorptance / scattering ratio After calculating AD1 / SD and AD2 / SD, the absorption ratio AD1 / AD2 is calculated, and the water content Q is specified based on the absorption ratio AD1 / AD2 in which a factor causing the error is eliminated. The water content Q of the paper P can be measured with extremely high accuracy.
[0102]
In the case where the present invention is applied to the fourth embodiment, as shown in FIG. 17, light in the wavelength range of 1.8 μm or more (transmitted light T1) of the transmitted light T is detected by the detector 42. At the same time, since light in the wavelength range of less than 1.8 μm (transmitted light T2) is detected by the detector 45, the water content Q of the paper P is extremely high by the same operation as that shown in FIGS. It can be measured with high accuracy.
[0103]
Although not shown, when applied to the fifth and sixth embodiments, it is possible to improve the measurement accuracy of the water content Q in the same manner as when applied to the second to fourth embodiments. Can be.
[0104]
In the first embodiment (see FIGS. 1 and 2), since the paper P is transported on the reflection plate 20 in measuring the water content Q of the paper P, the reflection plate 20 is fixed. However, the present invention is not limited to this. For example, when the paper P is not transported on the reflection plate 20, for example, when the paper P is stored in a tray of a copier, a printer, or the like. Instead of the paper P, the reflection plate 20 may be moved between a measurement position (the position of the reflection plate 20 shown in FIGS. 1 and 2) and a retracted position away from the measurement position. Also in this case, it is possible to reflect the irradiation light I toward the detector 4 on the reflection plate 20 as necessary, so that the same effect can be obtained.
[0105]
In the first embodiment, the reflection plate 20 is used as a member that reflects the irradiation light I emitted from the light source 1 as reflected light R0 toward the detector 4. However, the present invention is not limited to this. However, as long as the irradiation light I can be reflected similarly to the reflection plate 20, the reflection plate 20 may be replaced with another member. The “other member” includes, for example, another integrating sphere having an opening at a position corresponding to the opening 2KB of the integrating sphere 2.
[0106]
In the second embodiment (see FIG. 4), the reflecting plate 20 described in the first embodiment is not provided. However, the present invention is not limited to this. 20 may be provided. In this case, the reflecting plate 20 is different from the first embodiment in which the irradiation light I is reflected as the reflected light R0. And has a function of reflecting the light transmitted through the detector 4 toward the detector 4. In this case, regardless of the presence or absence of the transparency of the paper P, the ratio of the light guided to the detector 4 is maintained substantially constant, so that the calculation accuracy of the water content Q can be further improved.
[0107]
In the second embodiment, the opening 2KD is provided in the integrating sphere 2 at a position facing the opening 2KA, and the lens 51, the filter 61, and the detector 41 are arranged corresponding to the opening 2KD. However, the present invention is not limited to this. For example, as shown in FIG. 18, an opening 2KD is provided at a position that does not face the opening 2KA. The filter 61 and the detector 41 may be arranged. In this case, unlike the second embodiment in which the irradiation light I reflected by the baffle 71 can be detected by the detector 41 in addition to the irradiation light I reflected by the integrating sphere 2, the reflection by the baffle 71 Since the irradiation light I can be detected by the detector 41 in a state in which the ratio of the reflected light and the scattering in the integrating sphere 2 is increased while the ratio of the reflected light is increased, the calculation accuracy of the water content Q can be further improved. . Note that FIG. 18 schematically illustrates a planar configuration of the moisture content measuring device, and includes a light source 1, an integrating sphere 2, 21 (opening portions 2KA, 2KD), a detector, and the like in a series of components illustrated in FIG. Only 41, lens 51, filter 61 and baffle 71 are shown.
[0108]
Further, the configuration of the moisture content measuring device described in the first to sixth embodiments and the modified examples shown in FIGS. 12 to 18 may be individually applied to the moisture content measuring device as described above. Or may be combined as appropriate and applied to a water content measuring device. Specifically, for example, as shown in FIG. 19, the configuration described in the second embodiment (see FIG. 4) and the configuration described in the third embodiment (see FIG. 5) are combined. It may be. In this case, the same effects as those of the above embodiments and modifications can be obtained.
[0109]
Further, in each of the above embodiments and modifications, the case where the moisture content of the paper is measured using the moisture content measuring device of the present invention has been described. However, the present invention is not necessarily limited to this. By using the water content measuring device described above, it is also possible to measure the water content of an object to be measured other than paper. Examples of the “other measured object” include cloth, soil, dough such as bread and noodles, and food such as laver and tea. In this case, the same effects as those of the above embodiments can be obtained.
[0110]
【Example】
Next, specific examples according to the present invention will be described.
[0111]
As a representative of a series of moisture content measuring devices of the present invention, the moisture content measuring device shown in FIGS. 1 and 2 as the first embodiment (hereinafter simply referred to as “first moisture content measuring device of the present invention”) The result shown in FIG. 20 was obtained when the water content Q of the paper P was measured using the above-described method, and the water content measuring device shown in FIGS. 12 and 13 as a modification of the first embodiment. When the water content Q of the paper P was measured using the “second water content measuring device of the present invention” (hereinafter simply referred to as “the second water content measuring device of the present invention”), the result shown in FIG. 21 was obtained. FIG. 20 shows the correlation between the absorption / scattering ratio and the water content. The “horizontal axis” indicates the absorption / scattering ratio AD / SD obtained using the Kubelka-Munk function, The "axis" indicates the water content Q (% by mass). FIG. 21 shows the correlation between the absorptance ratio and the water content. The “horizontal axis” indicates the absorptivity ratio AD1 / AD2 obtained using the Kubelka-Munk function, and the “vertical axis” indicates the abscissa. The amount of water Q (% by mass) is shown. “O” shown in FIG. 20 and FIG. 21 is MY RECYCLE PAPER 100W manufactured by NBS Ricoh Co., Ltd. 902010 is shown, and "□" is the result obtained when Plus Paper Co., Ltd. (neutral paper) CR-220 is used as the other paper P.
[0112]
As the water content measuring device, an integrating sphere 2 having a scattered film 2S made of gold on the inner surface of a sphere 2G having a fine surface unevenness structure was used, and a filament bulb was used as a light source 1. When measuring the water content Q, the intensity of the light detected by the detectors 4 and 43 while the light source 1 is operated (the intensity of the mixed light obtained by mixing the reflected light R1 and the light caused by the background radiation). The difference between the intensity of the light detected by the detectors 4 and 43 in the state where the light source 1 is stopped (the intensity of the light caused by the background radiation) is calculated as the intensity of the reflected light R1 excluding the influence of the background radiation. Thus, the water content Q was calculated while eliminating the influence of the background radiation.
[0113]
As can be seen from the results shown in FIG. 20, when the water content Q was measured using the first water content measuring device of the present invention, the water content Q was determined from the Kubelka-Munk function for any paper P having different paper quality. The measured value of the water content Q increased as the obtained absorption / scattering ratio AD / SD increased. In this case, although there was some variation depending on the paper quality, an almost proportional relationship was recognized between the absorption / scattering ratio AD / SD and the water content Q. From this, it was confirmed that the water content Q of the paper P can be measured with high accuracy by using the first water content measuring device of the present invention.
[0114]
Further, as can be seen from the results shown in FIG. 21, when the water content Q was measured using the second water content measurement device of the present invention, the absorption ratio AD1 / AD2 increased for any paper P. Accordingly, the measured value of the water content Q increased. In this case, a sufficient proportional relationship was recognized between the absorption ratio AD1 / AD2 and the water content Q, regardless of the paper quality. From this, it was confirmed that the water content Q of the paper P can be measured with higher accuracy by using the second water content measuring device of the present invention.
[0115]
【The invention's effect】
As described above, the water content measuring device according to the present invention includes the irradiation light intensity detecting means for detecting the intensity of the irradiation light emitted from the light source, the detection result of the irradiation light intensity detecting means, and the reflected light intensity. Since the water content of the object to be measured is calculated based on the detection result of the detection means, the water content is calculated in consideration of, for example, the intensity change of the irradiation light due to the deterioration of the light source or the like. Therefore, the reflectance of the object to be measured is calculated in consideration of the intensity change of the irradiation light as well as the intensity of the reflected light, so that the water content of the object to be measured can be measured with high accuracy.
[0116]
In addition, in addition to the above, the water content measuring device according to the present invention includes a reflection / scattering unit that guides the irradiation light emitted from the light source to the object by reflecting and scattering the irradiation light, so that the intensity of the reflected light is improved. From the viewpoint of the angle distribution, a factor that may cause an error in the measurement accuracy of the water content is removed, and the error is reduced, so that the water content of the measured object can be measured with higher accuracy.
[0117]
Further, the water content measuring apparatus according to the present invention includes transmitted light intensity detecting means for detecting the intensity of transmitted light transmitted through the object to be measured, the detection result of the irradiation light intensity detecting means and the detection result of the reflected light intensity detecting means. In addition, if the water content is calculated based on the detection result of the transmitted light intensity detecting means, the dependency of the reflectance on the thickness of the object to be measured is corrected by the amount including the transmitted light intensity, and the water content is calculated. Since the calculation accuracy of is improved, the water content of the object to be measured can be measured with higher accuracy so that the influence of transmitted light cannot be ignored.
[0118]
Further, in the water content measuring device according to the present invention, of the light guided to the irradiation light intensity detecting means, the reflected light intensity detecting means and the transmitted light intensity detecting means, light having a wavelength range of 1.8 μm or more is selectively transmitted. If an optical filter is provided, the light in the wavelength range of 1.8 μm or more useful for measuring the water content of the irradiation light, the reflected light, and the transmitted light is utilized by utilizing the wavelength separation effect of the optical filter. Since the light is guided to the irradiation light intensity detector, the reflected light intensity detector, and the transmitted light intensity detector, the intensity of the irradiation light, the reflected light, and the transmitted light can be detected stably and easily.
[0119]
Further, in the water content measuring device according to the present invention, the light guided to the irradiation light intensity detecting means, the reflected light intensity detecting means, and the transmitted light intensity detecting means is converted to light in a wavelength range of 1.8 μm or more and wavelength of less than 1.8 μm. And an optical separation means for separating the light into the light in the wavelength range of 1.8 μm or more, and the irradiation light intensity detection means, the reflected light intensity detection means, and the transmitted light intensity detection means. If the intensity of light in a wavelength range of less than 8 μm is separately detected, the intensity of light in a wavelength range of 1.8 μm or more with high water absorbability and the wavelength of less than 1.8 μm with low water absorbability are detected. Since the calculation accuracy is improved by eliminating the influence of the fluctuation of the scattering rate based on the difference between the light intensity of the region and the fluctuation, the water content of the measured object can be measured with extremely high accuracy.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a schematic configuration of a moisture content measuring device according to a first embodiment of the present invention when detecting reflected light intensity.
FIG. 2 is a cross-sectional view illustrating a schematic configuration of the water content measuring device illustrated in FIG. 1 when detecting irradiation light intensity.
FIG. 3 is a block diagram showing a block configuration of the water content measuring device shown in FIGS. 1 and 2.
FIG. 4 is a cross-sectional view illustrating a schematic configuration of a water content measuring device according to a second embodiment of the present invention.
FIG. 5 is a cross-sectional view illustrating a schematic configuration when detecting a reflected light intensity and a transmitted light intensity of the moisture content measuring device according to the third embodiment of the present invention.
6 is a cross-sectional view illustrating a schematic configuration of the moisture content measuring device illustrated in FIG. 5 when detecting irradiation light intensity.
FIG. 7 is a sectional view illustrating a schematic configuration of a water content measuring device according to a fourth embodiment of the present invention.
FIG. 8 is a cross-sectional view illustrating a schematic configuration of a moisture content measuring device according to a fifth embodiment of the present invention before paper conveyance.
FIG. 9 is a cross-sectional view illustrating a schematic configuration of the moisture content measuring device illustrated in FIG. 8 after paper conveyance.
FIG. 10 is a cross-sectional view illustrating a schematic configuration of a water content measuring device according to a sixth embodiment of the present invention before paper reversal.
11 is a cross-sectional view illustrating a schematic configuration of the water content measuring device illustrated in FIG. 10 after reversing the paper.
FIG. 12 is a cross-sectional view for explaining a modified example (at the time of detecting reflected light intensity) relating to the water content measuring device according to the first embodiment of the present invention.
13 is a cross-sectional view for explaining the water content measuring device (when detecting the irradiation light intensity) shown in FIG.
FIG. 14 is a cross-sectional view illustrating a modified example of the water content measuring device according to the second embodiment of the present invention.
FIG. 15 is a cross-sectional view for explaining a modified example (at the time of detecting the intensity of reflected light and the intensity of transmitted light) relating to the water content measuring device according to the third embodiment of the present invention.
FIG. 16 is a cross-sectional view for explaining the water content measuring device shown in FIG. 15 (when detecting irradiation light intensity).
FIG. 17 is a cross-sectional view for explaining a modification of the moisture content measuring device according to the fourth embodiment of the present invention.
FIG. 18 is a plan view for explaining another modified example of the water content measuring device according to the second embodiment of the present invention.
FIG. 19 is a cross-sectional view for explaining another modified example of the water content measuring device of the present invention.
FIG. 20 is a diagram showing the correlation between the absorption / scattering ratio and the water content for the water content measurement device of the present invention.
FIG. 21 is a diagram showing a correlation between an absorption ratio and a water content in another water content measuring device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Light source, 2, 21, 22 ... Integrating sphere, 2KA-2KD, 22KA, 22KB ... Opening, 2G, 21G, 22G ... Sphere, 2M, 21M, 22M ... Scattering surface, 2S, 21S, 22S ... Scattering film, 4, 41-45 detector, 5 lens, 6, 61, 62 filter, 7, 71 baffle, 8 memory, 9 controller, 10 amplifier, 11 A / D converter, 20 reflector , 32: transflector, 34: reversing mechanism, 100A, 100B: water content measuring part, AD: absorption rate, AD / SD: absorption / scattering ratio C: calibration curve data, I (I1, I2) ... Irradiation light, G: printing screen, P: paper, PX: front surface, PY: back surface, R0 (R01, R02), R (R1, R2): reflected light, RD: reflectance, SD: scattering ratio, T (T1) , T2): transmitted light, Q: water content.

Claims (13)

A light source,
Irradiation light intensity detecting means for detecting the intensity of irradiation light emitted from the light source to the object to be measured,
Reflected light intensity detecting means for detecting the intensity of the reflected light reflected on the object to be measured,
A water content measuring device comprising: a calculating means for calculating a water content of the measured object based on at least a detection result of the irradiation light intensity detecting means and a detection result of the reflected light intensity detecting means. 2. The water content measuring device according to claim 1, wherein the irradiation light intensity detecting means is different from the reflected light intensity detecting means and directly detects the intensity of the irradiation light. Further, a reflecting means for reflecting the irradiation light toward the reflected light intensity detecting means,
2. The water content measuring device according to claim 1, wherein the reflected light intensity detection unit also functions as the irradiation light intensity detection unit, and indirectly detects the intensity of the irradiation light via the reflection unit. 3. . 4. The apparatus according to claim 1, further comprising a reflection and scattering unit that guides the irradiation light emitted from the light source to the object by reflecting and scattering the irradiation light. 5. Water content measuring device. 5. The water content measuring device according to claim 4, wherein said reflection scattering means is an integrating sphere. Further, a transmitted light intensity detecting means for detecting the intensity of transmitted light transmitted through the object,
The calculating means calculates the water content of the measured object based on the detection result of the transmitted light intensity detecting means together with the detection result of the irradiation light intensity detecting means and the detection result of the reflected light intensity detecting means. The water content measuring device according to any one of claims 1 to 5, characterized in that: The apparatus further comprises a selective transmission unit that selectively transmits as a transmitted light a part of the light transmitted through the object to be transmitted to the transmitted light intensity detection unit. 6. The moisture content measuring device according to 6. 2. The optical filter according to claim 1, further comprising an optical filter for selectively transmitting light in a wavelength range of 1.8 μm or more out of the light guided to the irradiation light intensity detection means and the reflected light intensity detection means. A water content measuring device according to any one of claims 1 to 7. 9. The water content measuring device according to claim 8, further comprising an optical filter for selectively transmitting light in a wavelength range of 1.8 [mu] m or more out of the light guided to the transmitted light intensity detecting means. The water content measuring device according to claim 8, wherein the optical filter is made of germanium. An optical separation unit that separates light guided to the irradiation light intensity detection unit and the reflected light intensity detection unit into light having a wavelength range of 1.8 μm or more and light having a wavelength range of less than 1.8 μm;
The irradiation light intensity detection means and the reflected light intensity detection means separate the light intensity in the wavelength range of 1.8 μm or more and the light intensity in the wavelength range of less than 1.8 μm separated by the optical separation means. The water content measuring device according to any one of claims 8 to 10, wherein the water content is measured by the following method. Optical separation means for separating the light guided to the transmitted light intensity detection means into light in a wavelength range of 1.8 μm or more and light in a wavelength range of less than 1.8 μm;
The transmitted light intensity detection means separately detects the intensity of light in a wavelength range of 1.8 μm or more and the intensity of light in a wavelength range of less than 1.8 μm separated by the optical separation means. The water content measuring device according to claim 11, wherein 13. The water content measuring device according to claim 11, wherein the optical separating unit is a half mirror.

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