JP3867614B2 - Paper feeder - Google Patents

Description

【００４８】
尚、上記状態方程式及び出力方程式において、Ｒａ，Ｌａは、夫々、給紙モータ２０の電機子回路の抵抗，インダクタンスであり、Ｊｉ，Ｄｉは、夫々、給紙モータ２０の負荷となる給紙機構（詳しくはベルト１７や給紙ローラ１０等）の慣性モーメント，粘性抵抗であり、Ｋｔはトルク定数であり、Ｋｅは起電力定数である。
【００４９】
そして、上記のように記述される動的モデル及びこの動的モデルを基に状態推定器ＯＢＳを構築する具体的手法については、従来より知られている（例えば、（株）コロナ社発行、古田勝久著、「基礎システム理論」参照）ので、ここではこれ以上の説明は省略する。
【００５０】
次に、図４は、用紙４を給紙する際にＣＰＵ３０が行う給紙処理を表すフローチャートである。
図４に示すように、この給紙処理では、ＣＰＵ３０は、まずレジスタ群１１０の各レジスタに上述した各種パラメータをセットする（Ｓ１１０）。つまり、ＣＰＵ３０は、タイミング設定レジスタ１１２に演算時間ｔｏをセットし、目標設定レジスタ１１３に目標量ｒをセットし、第１ゲイン設定レジスタ１１５に積分ゲインＦ１をセットし、第２ゲイン設定レジスタ１１６に状態フィードバックゲインＦ２をセットする。
【００５１】
尚、このとき、ＣＰＵ３０は、目標量ｒ毎にあらかじめ決められた値の積分ゲインＦ１および状態フィードバックゲインＦ２を各レジスタ１１５、１１６にセットする。ここでは、目標量ｒの値が大きいほど、絶対値の大きな積分ゲインＦ１及び状態フィードバックゲインＦ２が各レジスタ１１５、１１６にセットされる。
【００５２】
次に、ＣＰＵ３０は、信号生成回路１００を起動させる（Ｓ１２０）。この処理においては、レジスタ群１１０を構成する起動設定レジスタ１１１への書き込みが行われ、これによって、信号生成回路１００全体が起動する。
このように信号生成回路１００が起動されると、制御信号生成部１３０が制御信号を生成し始め、同時にエラー検出部１６０も処理を開始する。そして、制御信号生成部１３０にて生成された制御信号（制御量ｕ）は、駆動信号生成部１４０にて駆動信号に変換されて、モータ駆動回路４０に入力され、モータ駆動回路４０が、その駆動信号に従い給紙モータ２０を駆動する。この結果、給紙ローラ１０が回転して、用紙載置板２に載置された用紙４が、搬送ローラ６へと搬送されることになる。
【００５３】
こうして信号生成回路１００を起動すると、ＣＰＵ３０は、給紙状態チェック部１２０の割込処理部１２３から停止割込信号が入力されたか否かを判断することにより停止割込信号が入力されるのを待ち（Ｓ１３０）、停止割込信号が入力されると、信号生成回路１００の作動を停止させ（Ｓ１４０）、当該給紙処理を終了する。
【００５４】
次に、図５は、信号生成回路１００の作動中（つまり用紙４の給紙時）にエラー検出部１６０が実行するエラー検出処理を表すフローチャートである。尚、エラー検出部１６０を含む信号生成回路１００は、いわゆるＡＳＩＣからなり、ハードウェアとして動作するものであるが、ここでは理解を容易にするため、ハードウェアの動作をフローチャートに置き換えて説明する。
【００５５】
図５に示すように、エラー検出部１６０は、起動直後には、紙無しエラー判定処理（Ｓ２１０〜Ｓ２３０）を実行する。
この紙無しエラー判定処理は、演算処理部１３１の状態推定器ＯＢＳから、状態推定器ＯＢＳにて推定された給紙モータ２０の電流値（推定電流）ｉを取得し（Ｓ２１０）、その取得した推定電流ｉの値と紙無しエラー判定用の第１判定値ｉａとを比較し（Ｓ２２０）、推定電流ｉが第１判定値ｉａ以下であれば（Ｓ２２０：ＮＯ）、当該紙無しエラー判定処理を開始してから所定の判定時間ｔ１が経過したか否かを判断し（Ｓ２３０）、判定時間ｔ１が経過していなければ（Ｓ２３０：ＮＯ）、再度Ｓ２１０に移行する、といった手順で実行される。
【００５６】
そして、この紙無しエラー判定処理にて、推定電流ｉが第１判定値ｉａよりも大きくなったと判断されると（Ｓ２２０：ＹＥＳ）、用紙載置板２に用紙４がセットされておらず、給紙モータ２０に通常時よりも大きな負荷が加わっている状態（つまり紙無しエラー状態）であるとして、給紙モータ２０の動作を停止するために、割込処理部１２３に対し作動停止指令を出力し（Ｓ２４０）、表示装置５０に、紙無しエラーに対するエラーメッセージ、例えば、「用紙を補給してください。」、を表示させ（Ｓ２５０）、当該処理を終了する。
【００５７】
次に、上記紙無しエラー判定処理にて、判定時間ｔ１が経過したと判断されると（Ｓ２３０：ＹＥＳ）、今度は、給紙ミスエラー判定処理（Ｓ２６０〜Ｓ２８０）を実行する。
この給紙ミスエラー判定処理は、演算処理部１３１の状態推定器ＯＢＳから推定電流ｉを取得し（Ｓ２６０）、その取得した推定電流ｉの値と給紙ミスエラー判定用の第２判定値ｉｂとを比較し（Ｓ２７０）、推定電流ｉが第２判定値ｉｂ以上であれば（Ｓ２７０：ＮＯ）、当該給紙ミスエラー判定処理を開始してから所定の判定時間ｔ２が経過したか否かを判断し（Ｓ２８０）、判定時間ｔ２が経過していなければ（Ｓ２８０：ＮＯ）、再度Ｓ２６０に移行する、といった手順で実行される。
【００５８】
そして、この給紙ミスエラー判定処理にて、推定電流ｉが第２判定値ｉｂよりも小さくなったと判断されると（Ｓ２７０：ＹＥＳ）、給紙ローラ１０が空転して給紙モータ２０に加わる負荷が通常時よりも小さくなっている状態（つまり給紙ミスエラー状態）であるとして、給紙モータ２０の動作を停止するために、割込処理部１２３に対し作動停止指令を出力し（Ｓ２９０）、表示装置５０に、給紙ミスエラーに対するエラーメッセージ、例えば、「用紙を再セットしてください。」、を表示させ（Ｓ２５０）、当該処理を終了する。
【００５９】
次に、上記給紙ミスエラー判定処理にて、判定時間ｔ２が経過したと判断されると（Ｓ２８０：ＹＥＳ）、今度は、ジャムエラー判定処理（Ｓ３１０〜Ｓ３３０）を実行する。
このジャムエラー判定処理は、演算処理部１３１の状態推定器ＯＢＳから推定電流ｉを取得し（Ｓ３１０）、その取得した推定電流ｉの値とジャムエラー判定用の第３判定値ｉｃとを比較し（Ｓ３２０）、推定電流ｉが第３判定値ｉｃ以下であれば（Ｓ３２０：ＮＯ）、レジセンサ１８の用紙検知出力がＯＮとなるか、カウンタ１２２によるカウント値が目標設定レジスタ１１３にセットされている目標量以上となって、用紙送りが完了したか否かを判断し（Ｓ３３０）、用紙送りが完了していなければ（Ｓ３３０：ＮＯ）、再度Ｓ３１０に移行する、といった手順で実行される。
【００６０】
そして、このジャムエラー判定処理にて、推定電流ｉが第３判定値ｉｃよりも大きくなったと判断されると（Ｓ３２０：ＹＥＳ）、給紙ローラ１０に用紙４が詰まり、給紙モータ２０に通常時よりも大きな負荷が加わっている状態（つまりジャムミスエラー状態）であるとして、給紙モータ２０の動作を停止するために、割込処理部１２３に対し作動停止指令を出力し（Ｓ３４０）、表示装置５０に、ジャムエラーに対するエラーメッセージ、例えば、「紙詰まりを取り除いてください。」、を表示させ（Ｓ３５０）、当該処理を終了する。
【００６１】
以上説明したように、本実施例の給紙装置においては、ＣＰＵ３０により信号生成回路１００が起動されて、紙送り動作を開始すると、エラー検出部１６０が、その紙送り動作の経過時間と状態推定器ＯＢＳにより推定された給紙モータ２０の電流値（推定電流）ｉとに基づき、紙無しエラー、給紙ミスエラー、及び、ジャムエラーを順に判定し、これら各エラーの何れかが発生していることを検出すると、割込処理部１２３からＣＰＵ３０へ停止割込信号を出力させて、給紙モータ２０の駆動を停止させると共に、表示装置５０に、エラー状態であることを報知するためのエラーメッセージを表示させる。
【００６２】
このため、本実施例の給紙装置によれば、上記各エラーを検出するための専用のセンサを設けることなく、上記各エラーを夫々高精度に検出することが可能となり、給紙装置（延いてはプリンタ）のコストアップを招くことなく、装置の信頼性を向上することができる。また、エラー検出時には、検出したエラーに対応するエラーメッセージを表示装置５０に表示するので、使用者は、給紙装置がエラー状態であることを認識して、正常状態に速やかに復帰させることができる。
【００６３】
尚、本実施例においては、給紙モータ２０，給紙ローラ１０等からなる図１に示した給紙機構が、本発明の紙送り手段に相当し、給紙ローラ１０の回転状態を検出するエンコーダ１２が、本発明の検出手段に相当する。また、制御量ｕを演算する演算処理部１３１は、本発明の制御手段に相当し、この演算処理部１３１に組み込まれた状態推定器ＯＢＳは、本発明の推定手段に相当する。また、エラー検出部１６０は、本発明のエラー検出手段に相当し、このエラー検出部１６０にて実行されるＳ２５０、Ｓ３００，Ｓ３５０の処理でエラーメッセージを表示するのに使用される表示装置５０は、本発明のエラー報知手段に相当する。
【００６４】
以上、本発明の一実施例について説明したが、本発明は上記実施例に限定されるものではなく、例えば、Ｓ２５０、Ｓ３００、Ｓ３５０におけるエラーメッセージの表示は、ＣＰＵ３０のソフトウェア処理によって実行するようにする等、種々の態様を採ることができる。［変形例１］
また、上記実施例では、エラー検出部１６０にて実行される給紙ミスエラー判定処理において、推定電流ｉが判定値ｉｂよりも小さくなった場合に、そのまま給紙ミスエラーが発生したと判断して、作動停止指令を出力するものとして説明したが、給紙ミスエラーは、一時的に発生しても、給紙ローラ１０の回転を継続させることによって、正常状態に復旧できることがある。
【００６５】
そこで、図５に示したＳ２６０〜Ｓ３００の手順で実現される給紙ミスエラー判定処理を、図６に示す手順で実行するように変更することで、給紙ミスエラー発生時に正常状態に自動復旧させることもできる。
即ち、図６に示す給紙ミスエラー判定処理では、Ｓ２７０にて、推定電流ｉが第２判定値ｉｂよりも小さくなったと判断されると、当該処理の開始時にリセット（値「０」）される給紙ミスエラー判定フラグＦがリセット状態であるか否かを判断する（Ｓ２８２）。そして、このフラグＦがリセット状態であれば、給紙ミスエラー判定処理の継続時間を計時する図示しないタイマＴ２の計時動作を一時的に停止し（Ｓ２８４）、給紙ミスエラー状態の経過時間を計時する図示しないタイマＴ３の計時動作を開始若しくは再開させ（Ｓ２８６）、フラグＦを値「１」にセットした後（Ｓ２８８）、Ｓ２８９に移行し、逆に、フラグＦがリセット状態であれば、Ｓ２８９にそのまま移行する。
【００６６】
そして、Ｓ２８９では、タイマＴ３による計時時間（給紙ミスエラー状態の経過時間）が予め設定された判定時間ｔ３に達したか否かを判断し、判定時間ｔ３に達していなければ、Ｓ２６０に移行し、逆に、判定時間ｔ３に達していれば、Ｓ２９０、Ｓ３００の処理を実行して、当該処理を終了する。
【００６７】
また、Ｓ２７０にて、推定電流ｉが第２判定値ｉｂ以上であると判断された場合には、給紙ミスエラー判定フラグＦがセットされているか否かを判断する（Ｓ２７２）。そして、このフラグＦがセットされていなければ、そのままＳ２８０に移行し、逆に、フラグＦがセットされていれば、タイマＴ３による給紙ミスエラー状態の経過時間の計時動作を一時的に停止し（Ｓ２７４）、タイマＴ２による給紙ミスエラー判定処理の継続時間の計時動作を開始若しくは再開させ（Ｓ２７６）、フラグＦをリセットした後（Ｓ２７８）、Ｓ２８０に移行する。
【００６８】
このように、図６に示す給紙ミスエラー判定処理では、推定電流ｉが第２判定値ｉｂよりも小さくなって、給紙ミスエラーを判定すると、タイマＴ３を用いて、給紙ミスエラー状態の経過時間を計時し、その経過時間が判定時間ｔ３に達する迄は、給紙ミスエラー判定処理を継続し、その経過時間が判定時間ｔ３に達した場合に、給紙ミスエラーからの自動復旧は困難であると判断して、Ｓ２９０、Ｓ３００の処理を実行する。
【００６９】
従って、この給紙ミスエラー判定処理によれば、推定電流ｉから給紙ミスエラーを判定しても、給紙ローラ１０を継続して駆動することにより、給紙ミスエラーから正常状態へと自動復旧させることが可能となり、給紙装置の信頼性及び使い勝手を向上できる。［変形例２］
また次に、上記実施例では、上記各エラーの判定を、状態推定器ＯＢＳにて推定された推定電流ｉを用いて行うものとして説明したが、図７に示すように、モータ駆動回路４０内に電流検出手段としての電流検出器４１が組み込まれている場合には、エラー検出部１６０において、図８に示すエラー検出処理を実行するようにしても、上記各エラーを検出することができる。
【００７０】
即ち、図８に示すエラー検出処理では、まず、演算処理部１３１の状態推定器ＯＢＳから推定電流ｉを取得すると共に、電流検出器４１から給紙モータ２０に実際に流れている電流（検出電流）ｉｓを取得する（Ｓ４１０）。
そして、その取得した検出電流ｉｓと推定電流ｉとの偏差の絶対値を電流偏差△ｉとして算出し（Ｓ４２０）、その算出した電流偏差△ｉと、予め設定されたエラー判定用の判定基準値△ｉｏとを比較する（Ｓ４３０）。
【００７１】
そして、電流偏差△ｉが判定基準値△ｉｏよりも大きい場合には（Ｓ４３０：ＹＥＳ）、上述した紙無しエラー、給紙ミスエラー、ジャムエラー、といった何らかのエラーが発生しているものと判断して、給紙モータ２０の動作を停止するために、割込処理部１２３に対し作動停止指令を出力し（Ｓ４５０）、表示装置５０にエラーメッセージを表示させ（Ｓ４６０）、当該処理を終了する。
【００７２】
また、電流偏差△ｉが判定基準値△ｉｏ以下である場合には（Ｓ４３０：ＮＯ）、エラーは発生していないものと判断して、Ｓ４４０に移行し、用紙送りが完了したか否かを判断する。そして、用紙送りが完了していなければ（Ｓ４４０：ＮＯ）、再度Ｓ４１０に移行し、逆に、用紙送りが完了していれば（Ｓ４４０：ＹＥＳ）、当該処理を終了する。
【００７３】
このように、給紙モータ２０に流れる電流を検出する電流検出器４１が備えられている場合には、その電流検出器４１にて検出された電流値（検出電流）ｉｓと状態推定器ＯＢＳにて推定された推定電流ｉとの偏差△ｉを求め、その電流偏差△ｉと判定基準値△ｉｏとを比較することによっても、エラー状態を検出できる。［変形例３］
一方、上記実施例及び変形例１，２では、状態推定器ＯＢＳにて推定された推定電流ｉを用いてエラー状態を検出するものとして説明したが、エラー状態の検出には、必ずしも推定電流ｉを用いる必要はなく、状態推定器ＯＢＳにて推定された給紙ローラ１０の回転角度（推定角度）θ若しくは角速度（推定角速度）ωを用いるようにしてもよい。
【００７４】
そして、状態推定器ＯＢＳにて推定された推定角度θを用いる場合には、エラー検出処理を図９に示す手順で実行し、状態推定器ＯＢＳにて推定された推定角速度ωを用いる場合には、エラー検出処理を図１０に示す手順で実行するようにすればよい。尚、図９、図１０に示すエラー検出処理は、基本的には、図８に示したエラー検出処理と同様であり、エラー判定に用いるパラメータが異なるだけである。
【００７５】
即ち、図９に示すエラー検出処理では、演算処理部１３１の状態推定器ＯＢＳから推定角度θを取得すると共に、エンコーダ１２からの検出信号に基づき得られる給紙ローラ１０の実際の回転角度（検出角度）θｓを取得する（Ｓ４１０′）。そして、その取得した検出角度θｓと推定角度θとの偏差の絶対値を角度偏差△θとして算出し（Ｓ４２０′）、その算出した角度偏差△θと、予め設定されたエラー判定用の判定基準値△θｏとを比較する（Ｓ４３０′）。
【００７６】
そして、角度偏差△θが判定基準値△θｏよりも大きい場合には（Ｓ４３０′：ＹＥＳ）、上述した紙無しエラー、給紙ミスエラー、ジャムエラー、といった何らかのエラーが発生しているものと判断して、Ｓ４５０、Ｓ４６０の処理を実行した後、当該処理を終了する。
【００７７】
また逆に、角度偏差△θが判定基準値△θｏ以下である場合には（Ｓ４３０′：ＮＯ）、エラーは発生していないものと判断して、Ｓ４４０に移行し、用紙送りが完了したか否かを判断する。そして、用紙送りが完了していなければ（Ｓ４４０：ＮＯ）、再度Ｓ４１０に移行し、用紙送りが完了していれば（Ｓ４４０：ＹＥＳ）、当該処理を終了する。
【００７８】
また次に、図１０に示すエラー検出処理では、演算処理部１３１の状態推定器ＯＢＳから推定角速度ωを取得すると共に、エンコーダ１２からの検出信号に基づき得られる給紙ローラ１０の実際の回転角速度（検出角速度）ωｓを取得する（Ｓ４１０″）。そして、その取得した検出角速度ωｓと推定角速度ωとの偏差の絶対値を角速度偏差△ωとして算出し（Ｓ４２０″）、その算出した角速度偏差△ωと、予め設定されたエラー判定用の判定基準値△ωｏとを比較する（Ｓ４３０″）。
【００７９】
そして、角速度偏差△ωが判定基準値△ωｏよりも大きい場合には（Ｓ４３０″：ＹＥＳ）、上述した紙無しエラー、給紙ミスエラー、ジャムエラー、といった何らかのエラーが発生しているものと判断して、Ｓ４５０、Ｓ４６０の処理を実行した後、当該処理を終了する。
【００８０】
また逆に、角速度偏差△ωが判定基準値△ωｏ以下である場合には（Ｓ４３０″：ＮＯ）、エラーは発生していないものと判断して、Ｓ４４０に移行し、用紙送りが完了したか否かを判断する。そして、用紙送りが完了していなければ（Ｓ４４０：ＮＯ）、再度Ｓ４１０に移行し、用紙送りが完了していれば（Ｓ４４０：ＹＥＳ）、当該処理を終了する。
【００８１】
このように、給紙装置には、給紙ローラ１０（延いては給紙モータ２０）の回転状態を検出するエンコーダ１２が備えられ、そのエンコーダ１２の出力から給紙ローラ１０の実際の回転角度θ及び回転角速度ωを得ることができるので、その検出値（検出角度θｓ、検出角速度ωｓ）と状態推定器ＯＢＳにて推定された推定値（推定角度θ、推定角速度ω）との偏差を求め、その偏差と判定基準値とを比較することによっても、エラー状態を検出できる。
【００８２】
そして、このように、給紙ローラ１０（若しくは給紙モータ２０）の回転角度θ若しくは回転角速度ωの推定値と実測値との偏差からエラー状態を検出する際には、状態推定器ＯＢＳにて、給紙モータ２０に流れる電流を推定しないシステムにも適用できることから、例えば、演算処理部１３１においてモータ電流を制御量ｕとして演算する電流制御型の給紙装置にも適用できることになる。
【００８３】
つまり、演算処理部１３１においてモータ電流を制御量ｕとして演算する電流制御型の給紙装置では、状態推定器ＯＢＳにてモータ電流が推定されないので、上記実施例或いは変形例１，２のように、状態推定器ＯＢＳにより得られる推定電流を用いてエラー検出を行うことはできないが、当該変形例３のように、エラー検出に給紙ローラ１０（若しくは給紙モータ２０）の回転角度θ若しくは回転角速度ωの推定値を用いる場合には、状態推定器ＯＢＳにてモータ電流を推定する必要がないので、電流制御型の給紙装置にもそのまま適用できるようになるのである。
【００８４】
尚、以上の説明では、検出手段として、給紙ローラ１０の回転量を検出するエンコーダ１２を用いるものとして説明したが、検出手段としては、給紙モータ２０の回転量を検出するエンコーダを用いるようにしてもよく、或いは、ポテンショメータ等の他のセンサを用いるようにしてもよい。
【図面の簡単な説明】
【図１】 実施例の給紙装置の概略構成を表す説明図である。
【図２】 実施例の給紙装置を駆動するモータ制御系の構成を表すブロック図である。
【図３】 実施例の演算処理部の制御系統を表すブロック図である。
【図４】 実施例のＣＰＵにて実行される給紙処理を表すフローチャートである。
【図５】 実施例のエラー検出部で実行されるエラー検出処理を表すフローチャートである。
【図６】 エラー検出部で実行される給紙ミスエラー判定処理の変形例を表すフローチャートである。
【図７】 実施例の給紙装置を駆動するモータ制御系の変形例を表すブロック図である。
【図８】 推定電流と検出電流とを用いてエラー検出を行うエラー検出処理を表すフローチャートである。
【図９】 推定角度と検出角度とを用いてエラー検出を行うエラー検出処理を表すフローチャートである。
【図１０】 推定角速度と検出角速度とを用いてエラー検出を行うエラー検出処理を表すフローチャートである。
【図１１】 正常状態での給紙装置の挙動を表す説明図である。
【図１２】 エラー状態での給紙装置の挙動を表す説明図である。
【符号の説明】
２…用紙載置板、４…用紙、６…搬送ローラ、８…支持部材、９…分離部材、１０…給紙ローラ、１２…エンコーダ、１８…レジセンサ、２０…給紙モータ、２０ａ…回転軸、
４０…モータ駆動回路、４１…電流検出器、５０…表示装置、５６…エンコーダ、１００…信号生成回路、１１０…レジスタ群、１２０…給紙状態チェック部、１３０…制御信号生成部、１３１…演算処理部、ＡＤＤ１…第１加算器、ＡＤＤ２…第２加算器、ＩＮＴ…積分器、ＭＵＬ１…第１ゲイン積算器、ＭＵＬ２…第２ゲイン積算器、ＯＢＳ…状態推定器、１４０…駆動信号生成部、１５０…クロック生成部、１６０…エラー検出部。[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a paper feeding device used for supplying paper to a transport device that transports paper as an image recording medium in an image forming apparatus such as a printer or a facsimile machine.
[0002]
[Prior art]
  2. Description of the Related Art Conventionally, an image forming apparatus such as a printer or a facsimile apparatus includes a sheet feeding device that separates and feeds sheets stacked on a tray or a cassette one by one in order to supply sheets to an image forming unit. Are known.
[0003]
  This type of feeding device includes a roller that contacts the paper and feeds the paper by frictional force, and a drive source such as a motor for rotationally driving the roller, and is brought into a predetermined state in accordance with an external operation command. The sheet feeding operation is performed by controlling the rotation amount of the roller.
[0004]
  Conventionally, in this paper feeding device, a step motor has been used as a drive source for rotationally driving a roller. However, the step motor is driven by a pulse signal, and the operation becomes stepwise. Therefore, generation of noise during operation is inevitable.
  In recent years, the demand for quietness in image forming apparatuses has increased, and therefore, as a drive source, the use of a DC motor whose operation sound is relatively quiet due to a linear operation is being studied. When adopting a DC motor in an image forming apparatus, feedback control using a state estimator capable of increasing the control accuracy of motor drive is employed.
[0005]
[Problems to be solved by the invention]
  In the paper feeding device, there may be an error state such as a jammed paper jammed in the roller. At this time, if the load on the motor becomes large, the stepping motor will simply step out, and the device will not be damaged.
[0006]
  However, when a DC motor is used, the current increases in proportion to the load of the DC motor, so heat generation in the DC motor and the drive circuit increases, and if this state continues, a situation of burning out may be caused. There is sex. In particular, in a stalled state where the DC motor stops completely, the maximum current that can be passed by the DC motor is dangerous, so this state must be avoided.
[0007]
  In order to prevent this, it is necessary to detect various error states such as a jam, a paper out, and a pick mistake during the paper feeding operation so that the operating state of the DC motor can be changed.
  On the other hand, in order to detect this error state, a method of determining by monitoring with various sensors such as detection of presence / absence of paper, detection of the position of paper, detection of motor current, etc. can be considered. From the situation, it is desired to eliminate the addition of parts as much as possible and further improve the reliability.
[0008]
  The present invention has been made in view of these problems, and it is possible to detect an error during paper feeding without adding a new sensor in a paper feeding device using a DC motor as a driving source. Objective.
[0009]
[Means for Solving the Problems]
The sheet feeding device according to claim 1, which has been made to achieve the above object, uses a DC motor to rotate a roller in contact with the paper to feed the paper and to detect the rotation amount of the DC motor or the roller. And a state quantity (rotation amount) indicating the operating state of the paper feed means based on the rotation amount detected by the detection means and the control amount input to the DC motor. And an error detecting means for detecting an error state of the paper feeding means by comparing a state quantity estimated by the estimating means with a predetermined determination condition during the paper feeding operation by the paper feeding means. WhenThe error detection means determines a paper out error that there is no paper to be fed in the first period after the paper feeding operation is started by the paper feeding means, and in the second period after the first period, A paper feed error error due to idling is determined, and a jam error that is in a paper jam state is determined in a third period after the second period elapses until the paper feed operation by the paper feed unit ends.
[0010]
  That is, if the paper feeding device in the present invention is in an error state that causes a malfunction during the paper feeding operation, some abnormal operation occurs in the operation of the paper feeding device, so this behavior is estimated from the operating state estimated by the estimating means, It is something to be detected.
[0011]
  Here, the estimation means is called a state estimator in the so-called modern control theory, and includes a control input u (here, a control amount for controlling the drive source) to the paper feeding means to be controlled, and a control output y ( Here, the state quantity x representing the internal state of the controlled object (paper feeding means) is estimated based on the detection result by the detection means.
[0012]
  Specifically, the operating state of the paper feeding means is represented by the following state equation:
  d · x (t) / dt = A · x (t) + B · u (t)
  y (t) = C · x (t) From the output y (t) at time t and the input u (t), the estimated change amount d · x (t) / dt of the estimated state quantity x is obtained and integrated. The state quantity x (t) is estimated.
[0013]
  Therefore, the state quantity x (t) obtained by the estimation means represents the actual behavior of the paper feeding means that is the control target.
  As a result, according to the sheet feeding device of the present invention, it is possible to detect an error based on the estimation result by the estimation unit without adding new parts compared to the conventional one. In addition, since there are no additional parts, cost increases are reduced and product reliability is improved.
[0014]
  By the way, in the error state where the paper feeding device malfunctions, the state of the load on the DC motor has changed, so the value of the current flowing through the DC motor is different from the value during normal operation.
  For example, FIG. 11A shows the change in the rotation amount of the roller when the paper feeding device is operating normally, and FIG. 11B shows the change in the current flowing through the DC motor during the normal operation. FIG. 12A shows a change in the rotation amount of the roller in a jam error state in which the paper is jammed during the paper feeding operation and the rotation of the roller is stopped. FIG. It represents a change in the current flowing through the DC motor in the jam error state.
[0015]
  As is apparent from these figures, the current flowing through the DC motor during normal operation of the paper feeding device once increases in the positive direction immediately after the start of paper feeding and then changes to the negative side. Although it converges to a very small current value near “0”, in the jam error state, the rotation of the roller stops with the occurrence of the jam error. Therefore, the current flowing through the DC motor is extremely small compared to the normal current value. It gets bigger.
[0016]
  Therefore, the error state of the paper feeding device can be accurately determined by using the relationship between the currents that are different between the normal operation of the paper feeding device and the time when an error occurs.
  Therefore, in order to detect an error that occurred during the paper feeding operation by the error detection means, for example,GuessThe determining means may be configured to estimate an estimated current that is a current flowing through the DC motor, and the error detecting means may detect an error state using the estimated current.
[0017]
  That is, in this way, the paper feeding device can detect the error state of the paper feeding device based on the current (estimated current) flowing through the DC motor estimated by the estimating means.
  By the way, as errors that may occur in the paper feeding device, there is no paper at the paper feeding source, so there is no paper feeding error, and there is a small contact area with the paper roller at the beginning of paper feeding. If the paper is not fed properly, the roller will run idle on the paper, or the paper will jam during the paper feeding operation. There are jam errors that cannot be done.
[0018]
  And in the paper out error state, since there is no paper, the roller is pressed against the bottom surface of the paper tray, cassette, etc., so that it can not rotate, so the current flowing through the DC motor becomes larger than normal, This state occurs immediately after the paper feeding operation by the paper feeding device is started.
[0019]
  In the jam error state, the paper jams and the rotation of the roller stops. Therefore, the current flowing through the DC motor is larger than that in the normal state or no paper error, and the jam error is caused by the paper feeding device. This occurs after the paper is actually fed out after the paper feeding operation is started.
[0020]
  On the other hand, in the paper feed error state, since the roller slips while sliding on the paper, the value of the current flowing through the DC motor becomes smaller than normal. The paper feed error is generated when the roller starts to slide on the paper after the paper feeding operation by the paper feeding device is started. Therefore, the occurrence timing is later than the paper out error and earlier than the jam error. Become.
[0021]
  Therefore, in order to be able to specify the content of an error (in other words, the type of error state) instead of simply detecting the error state of the paper feeding device by the operation of the error detection means, Term1In the first period after the start of the paper feeding operation by the paper feeding means, the error detecting means determines that there is no paper to be fed and in the second period after the first period has elapsed. The paper misfeed error due to the idling of the roller is determined, and a jam error that causes a paper jam is determined in the third period after the second period elapses until the paper feeding operation by the paper feeding unit is completed. That's fine.
[0022]
[0023]
[0024]
[0025]
[0026]
[0027]
[0028]
  Next, the claim2In the paper feeding device described, when the error detection means detects an error, the control means controls the paper feed means so that the drive state is in accordance with the detection result.
  As a result, when one error is detected in the paper feeding device, the driving state of the paper feeding device can be changed to a driving state corresponding to the error state as one of the measures against the error. For example, in the case of an error in which a large current continues to flow through the DC motor, there are measures such as preventing the current from flowing, and if the error can be recovered from, an operation for returning is performed.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments (examples) of the present invention will be described below with reference to the drawings. [Example]
  FIG. 1 is an explanatory diagram showing the configuration of a sheet feeding device according to an embodiment to which the present invention is applied.
[0030]
  For example, in the ink jet printer, the paper feeding device according to the present exemplary embodiment takes out the paper 4 placed on the paper placement plate 2 one by one and supplies the paper 4 to the conveyance roller 6 that supplies the paper 4 to the image forming unit. A sheet feeding roller 10 and a DC motor (hereinafter referred to as a sheet feeding motor) 20 that rotationally drives the sheet feeding roller 10.
[0031]
  The paper feed roller 10 is rotatably positioned and fixed in the printer via the support member 8, and the paper discharge side tip portion of the paper placement plate 2 is biased by a spring or the like on the roller surface. It is pressed by the member 2a. Further, the sheet feeding plate 10 is fed from the sheet loading plate 2 by the rotation of the sheet feeding roller 10 on the downstream side in the rotation direction of the sheet feeding roller 10 with respect to the contact position of the sheet loading plate 2 with the sheet feeding roller 10. A separating member 9 is provided for separating only the uppermost sheet in contact with the roller surface of the sheet feeding roller 10 among the sheets 4 and supplying the sheet 4 to the conveying roller 6 side.
[0032]
  Accordingly, the paper 4 placed on the paper placement plate 2 is supplied to the transport roller 6 one by one by the rotation of the paper feed roller 10 and transported from the transport roller 6 to an image forming unit (not shown) inside the printer. Will be.
  Next, the support member 8 also supports a rotary slit plate 12 a and a pulley 14 that rotate together with the paper feed roller 10. On the other hand, the drive pulley 16 is assembled to the rotating shaft 20a of the paper feed motor 20 directly or via a gear. The drive pulley 16 and the pulley 14 on the paper feed roller 10 side are connected via a power transmission belt 17.
[0033]
  The rotating slit plate 12a is formed with slits at predetermined intervals along the circumference, and a pulse signal is generated around the periphery of the rotating slit plate 12a that is detected by the rotation of the rotating slit plate 12a. A photo interrupter 12b is arranged. In other words, the sheet feeding device of this embodiment includes a rotary encoder that includes a rotating slit plate 12a and a photo interrupter 12b as a rotation sensor for detecting the rotation state of the sheet feeding roller 10, and thus the sheet feeding motor 20. (Hereinafter simply referred to as an encoder) 12 is provided.
[0034]
  A registration sensor 18 for detecting that the paper 4 has been conveyed to the conveyance roller 6 is provided on the front side of the conveyance roller 6 in the paper supply path from the paper supply roller 10 to the conveyance roller 6. The registration sensor 18 is a switch that is turned on and off by its own rotating operation. When the paper 4 is not in front of the transport roller 6, the registration sensor 18 is in a vertical position and protrudes onto the paper feed path of the paper 4. When the paper 4 is transported to the protruding position, the paper 4 is brought into contact with the leading end of the paper 4 and rotated by a predetermined angle to be turned on.
[0035]
  Next, FIG. 2 is a block diagram showing the configuration of a motor control system that drives the paper feed motor 20.
  As shown in FIG. 2, the control system of the paper feed motor 20 includes a CPU 30 that controls the operation of the entire printer, a motor drive circuit 40 that drives the paper feed motor 20, and a signal that generates a drive signal that is input to the motor drive circuit 40. The generation circuit 100 and a display device 50 that displays various operation states of the printer (including error states of the paper feeding device) are included.
[0036]
  The signal generation circuit 100 is a so-called ASIC (Application Specific Integrated Circuit), a register group 110 that stores various parameters used to control the paper feed motor 20, and a pulse signal (encoder signal) input from the encoder 12. The sheet feeding state check unit 120 that checks the sheet feeding state, the control signal generation unit 130 that generates a control signal for controlling the sheet feeding motor 20, and the motor drive circuit 40 that receives the control signal generated by the control signal generation unit 130. A drive signal generation unit 140 that converts a drive signal (for example, a PWM signal) to be generated, a clock generation unit 150 that generates a clock signal for operation of the signal generation circuit 100 and supplies the clock signal to the entire signal generation circuit 100, and the present invention Error detection unit 1 is the main part And a 0, and the like. The clock generator 150 generates a clock signal having a cycle shorter than at least the shortest cycle of the encoder signal input from the encoder 12.
[0037]
  Among these, the register group 110 includes an activation setting register 111 for activating the signal generation circuit 100 and an encoder signal corresponding to the rotation amount of the paper feed roller 10 (in other words, the feed amount of the paper 4 by the paper feed roller 10). A target setting register 113 for setting a target amount r (in other words, a target paper feed amount) indicating the number of, and an integral gain “−F1”, which will be described later, used when the control signal generation unit 130 generates a control signal. A first gain setting register 115 for setting, a second gain setting register 116 for setting a state feedback gain “−F2”, which will be described later, and the like.
[0038]
  The start setting register 111 among the registers is a register in which a command for starting the signal generation circuit 100 is written, and when the start setting register 111 is written, the signal generation circuit 100 as a whole is written. Starts.
  The paper feed state check unit 120 includes an encoder edge detection unit 121 that detects that an encoder signal is input from the encoder 12, a counter 122 that counts the number of encoder signals detected by the encoder edge detection unit 121, and a registration sensor 18. From a registration sensor detection unit 124 that detects a signal from the CPU 30 and an interrupt processing unit 123 that outputs a stop interrupt signal to the CPU 30 to stop the CPU 30 from driving the paper feed motor 20 by the signal generation circuit 100. Become.
[0039]
  The interrupt processing unit 123 is set in the target setting register 113 when the sheet detection output of the registration sensor 18 is turned on or the count value by the counter 122 (in other words, the rotation amount of the paper feed roller 10). When the amount exceeds the target amount, a stop interrupt signal is output to the CPU 30. The interrupt processing unit 123 also stops the CPU 30 from interrupting when the error detection unit 160 detects an error state of the sheet feeding device and an operation stop command is input from the error detection unit 160. Output a signal.
[0040]
  On the other hand, the control signal generator 130 calculates a control amount u (in this embodiment, the drive voltage Vo of the paper feed motor 20) for controlling the paper feed motor 20, and a clock generator 150. The timer 132 for measuring time etc. which measures time based on the clock signal produced | generated by this is comprised.
[0041]
  Here, as shown in FIG. 3, the arithmetic processing unit 131 compares the count value (rotation amount of the paper feed roller 10) y by the counter 122 with the target amount r set in the target setting register 113, and compares these values. A first adder ADD1 for calculating a deviation, an integrator INT for discretely integrating the deviation calculated by the first adder ADD1, and an integral gain set in the first gain setting register 115 to a calculated value of the integrator INT A first gain integrator MUL1 that multiplies “−F1”, and generates a first control signal for driving and controlling the paper feed motor 20 according to the deviation.
[0042]
  In addition, the arithmetic processing unit 131 is configured to supply a sheet feeding motor based on a control signal (control amount u) for motor control output from the control signal generation unit 130 to the drive signal generation unit 140 and the count value y of the counter 122. 20, a state estimator (so-called observer) OBS for estimating the state quantity x indicating the state of the paper feed mechanism shown in FIG. 1 and the state quantity x estimated by the state estimator OBS. A second gain integrator MUL2 for multiplying the state feedback gain “−F2” set in the second gain setting register 116, and a second for driving and controlling the paper feed motor 20 according to the internal state of the paper feed mechanism. Generate a control signal.
[0043]
  Then, the arithmetic processing unit 131 adds the first control signal and the second control signal calculated by each of the gain integrators MUL1 and MUL2 by the second adder ADD2, thereby controlling the control amount of the sheet feeding motor 20. u is obtained, and this control amount u is output to the drive signal generation unit 140, whereby a drive signal for controlling the paper feed motor 20 with the control amount u is output from the drive signal generation unit 140 to the motor drive circuit 40. Let
[0044]
  Here, the state estimator OBS models the paper feed mechanism that supplies the paper 4 by the paper feed motor 20 as a dynamic linear system, and controls the paper feed amount using the input voltage to the paper feed motor 20 as the operation amount. When considered as a servo system, calculations are performed to realize the state feedback control. The state variable to be selected at that time is not unique as described in the state feedback control manual and the like, so it is necessary to select it appropriately according to the control system.
[0045]
  Therefore, in the present embodiment, there is an encoder 56 that can detect the rotation angle θ of the rotation shaft of the paper feed roller 10 driven by the paper feed motor 20 as the control output y. The current value i of the paper feed motor 20, the rotation angle θ of the paper feed roller 10, and the rotational angular velocity ω of the paper feed roller 10 which are parameters characterized by dynamic behavior are selected as state variables, and paper feed is performed as a control input. By selecting the drive voltage Vo that is the control amount u of the motor 20, the rotation angle θ (control output y) detected by the encoder 56 and the drive voltage Vo (control input u) of the paper feed motor 20 are used. The state quantity x (that is, the current value i of the paper feed motor 20, the rotation angle θ of the paper feed roller 10, and the rotational angular velocity ω of the paper feed roller 10) is calculated.
[0046]
  That is, in this embodiment, as a dynamic model representing the behavior of the sheet feeding mechanism, for example, a dynamic model described by a state equation and an output equation such as the following equation is constructed, and the state equation and the output equation are used as a basis. In addition, a state estimator OBS that estimates the current value i of the paper feed motor 20, the rotation angle θ of the paper feed roller 10, and the rotation angular velocity ω of the paper feed roller 10 as the state quantity x is realized.
[0047]
[Expression 1]

[0048]
  In the above state equation and output equation, Ra and La are the resistance and inductance of the armature circuit of the paper feed motor 20, respectively, and Ji and Di are the paper feed mechanisms that are the loads of the paper feed motor 20, respectively. (In detail, the moment of inertia and viscous resistance of the belt 17, the paper feed roller 10, etc.), Kt is a torque constant, and Ke is an electromotive force constant.
[0049]
  The dynamic model described above and a specific method for constructing the state estimator OBS based on this dynamic model have been conventionally known (for example, Corona, Inc., Furuta, Inc.). Katsuhisa, see "Basic System Theory"), so further explanation is omitted here.
[0050]
  Next, FIG. 4 is a flowchart showing a paper feed process performed by the CPU 30 when paper 4 is fed.
  As shown in FIG. 4, in this paper feed process, the CPU 30 first sets the various parameters described above in each register of the register group 110 (S110). That is, the CPU 30 sets the computation time to in the timing setting register 112, sets the target amount r in the target setting register 113, sets the integral gain F1 in the first gain setting register 115, and sets the integration gain F1 in the second gain setting register 116. The state feedback gain F2 is set.
[0051]
  At this time, the CPU 30 sets the integral gain F1 and the state feedback gain F2 having predetermined values for each target amount r in the registers 115 and 116, respectively. Here, as the value of the target amount r is larger, the integral gain F1 and the state feedback gain F2 having larger absolute values are set in the registers 115 and 116, respectively.
[0052]
  Next, the CPU 30 activates the signal generation circuit 100 (S120). In this process, writing to the activation setting register 111 that constitutes the register group 110 is performed, whereby the entire signal generation circuit 100 is activated.
  When the signal generation circuit 100 is activated in this way, the control signal generation unit 130 starts to generate a control signal, and at the same time, the error detection unit 160 also starts processing. The control signal (control amount u) generated by the control signal generation unit 130 is converted into a drive signal by the drive signal generation unit 140 and input to the motor drive circuit 40. The motor drive circuit 40 The paper feed motor 20 is driven according to the drive signal. As a result, the paper feed roller 10 rotates and the paper 4 placed on the paper placement plate 2 is transported to the transport roller 6.
[0053]
  When the signal generation circuit 100 is activated in this way, the CPU 30 determines whether or not the stop interrupt signal has been input from the interrupt processing unit 123 of the paper feed state check unit 120. Waiting (S130), when a stop interrupt signal is input, the operation of the signal generation circuit 100 is stopped (S140), and the paper feed process is terminated.
[0054]
  Next, FIG. 5 is a flowchart showing an error detection process executed by the error detection unit 160 while the signal generation circuit 100 is operating (that is, when the paper 4 is being fed). The signal generation circuit 100 including the error detection unit 160 includes a so-called ASIC and operates as hardware. However, for the sake of easy understanding, the hardware operation will be described with a flowchart.
[0055]
  As shown in FIG. 5, the error detection unit 160 executes a paper-out error determination process (S210 to S230) immediately after activation.
  In this paper absence error determination process, the current value (estimated current) i of the paper feed motor 20 estimated by the state estimator OBS is acquired from the state estimator OBS of the arithmetic processing unit 131 (S210). The value of the estimated current i is compared with the first determination value ia for determining an out-of-paper error (S220). If the estimated current i is equal to or less than the first determination value ia (S220: NO), the out-of-paper error determination process. It is determined whether or not a predetermined determination time t1 has elapsed since the start of the process (S230). If the determination time t1 has not elapsed (S230: NO), the process proceeds to S210 again. .
[0056]
  If it is determined that the estimated current i has become larger than the first determination value ia in this paper absence error determination process (S220: YES), the paper 4 is not set on the paper placement plate 2, and In order to stop the operation of the paper feed motor 20 on the assumption that a larger load is applied to the paper feed motor 20 than usual (that is, no paper error state), an operation stop command is issued to the interrupt processing unit 123. Output (S240), an error message for the paper out error, for example, “please replenish paper” is displayed on the display device 50 (S250), and the process ends.
[0057]
  Next, if it is determined that the determination time t1 has elapsed in the paper out error determination process (S230: YES), a paper feed error error determination process (S260 to S280) is executed next time.
  In this paper feed error determination process, the estimated current i is acquired from the state estimator OBS of the arithmetic processing unit 131 (S260), the value of the acquired estimated current i and the second determination value ib for paper feed error error determination. (S270), and if the estimated current i is greater than or equal to the second determination value ib (S270: NO), whether or not a predetermined determination time t2 has elapsed since the paper feed error error determination process was started (S280), and if the determination time t2 has not elapsed (S280: NO), the process proceeds to S260 again.
[0058]
  If it is determined in this paper feed error error determination process that the estimated current i is smaller than the second determination value ib (S270: YES), the paper feed roller 10 is idled and applied to the paper feed motor 20. Assuming that the load is smaller than normal (that is, a paper feed error state), an operation stop command is output to the interrupt processing unit 123 to stop the operation of the paper feed motor 20 (S290). ), An error message for a paper feed error, for example, “Reload paper” is displayed on the display device 50 (S250), and the process is terminated.
[0059]
  Next, when it is determined that the determination time t2 has elapsed in the paper feed error error determination process (S280: YES), a jam error determination process (S310 to S330) is executed next time.
  In the jam error determination process, an estimated current i is acquired from the state estimator OBS of the arithmetic processing unit 131 (S310), and the acquired estimated current i value is compared with a third determination value ic for determining a jam error. (S320) If the estimated current i is equal to or smaller than the third determination value ic (S320: NO), the sheet detection output of the registration sensor 18 is turned on, or the count value by the counter 122 is set in the target setting register 113. A determination is made as to whether or not the sheet feed has been completed (S330). If the sheet feed has not been completed (S330: NO), the process proceeds to S310 again.
[0060]
  If it is determined in this jam error determination process that the estimated current i is larger than the third determination value ic (S320: YES), the sheet 4 is jammed in the sheet feed roller 10, and the sheet feed motor 20 is In order to stop the operation of the paper feed motor 20 assuming that a larger load than that is applied (that is, a jam miss error state), an operation stop command is output to the interrupt processing unit 123 (S340), An error message for a jam error, for example, “Please remove the paper jam”, is displayed on the display device 50 (S350), and the process ends.
[0061]
  As described above, in the paper feeding device of this embodiment, when the signal generation circuit 100 is activated by the CPU 30 and the paper feeding operation is started, the error detection unit 160 estimates the elapsed time and state of the paper feeding operation. Based on the current value (estimated current) i of the paper feed motor 20 estimated by the device OBS, a paper out error, a paper feed error error, and a jam error are determined in order, and any of these errors occurs. Is detected, the interrupt processing unit 123 outputs a stop interrupt signal to the CPU 30 to stop the driving of the paper feed motor 20 and to notify the display device 50 that the error state has occurred. Display a message.
[0062]
  For this reason, according to the paper feeding device of the present embodiment, each error can be detected with high accuracy without providing a dedicated sensor for detecting each error. In other words, the reliability of the apparatus can be improved without increasing the cost of the printer. Further, when an error is detected, an error message corresponding to the detected error is displayed on the display device 50, so that the user can recognize that the paper feeding device is in an error state and promptly return it to a normal state. it can.
[0063]
  In this embodiment, the paper feed mechanism shown in FIG. 1 comprising the paper feed motor 20 and the paper feed roller 10 corresponds to the paper feed means of the present invention and detects the rotational state of the paper feed roller 10. The encoder 12 corresponds to the detection means of the present invention. The arithmetic processing unit 131 that calculates the control amount u corresponds to the control unit of the present invention, and the state estimator OBS incorporated in the arithmetic processing unit 131 corresponds to the estimation unit of the present invention. The error detection unit 160 corresponds to the error detection unit of the present invention, and the display device 50 used for displaying an error message in the processing of S250, S300, and S350 executed by the error detection unit 160 is as follows. This corresponds to the error notification means of the present invention.
[0064]
  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, the display of error messages in S250, S300, and S350 is executed by software processing of the CPU 30. For example, various modes can be adopted. [Modification 1]
  Further, in the above embodiment, in the paper feed error error determination process executed by the error detector 160, when the estimated current i becomes smaller than the determination value ib, it is determined that a paper feed error has occurred as it is. In the above description, the operation stop command is output. However, even if a paper feed error occurs temporarily, the normal state may be recovered by continuing the rotation of the paper feed roller 10.
[0065]
  Therefore, the paper feed error error determination process realized by the procedure of S260 to S300 shown in FIG. 5 is changed to be executed according to the procedure shown in FIG. 6, so that the normal state is automatically restored when a paper feed error occurs. It can also be made.
  That is, in the paper feed error determination process shown in FIG. 6, if it is determined in S270 that the estimated current i has become smaller than the second determination value ib, it is reset (value “0”) at the start of the process. It is determined whether the paper feed error error determination flag F is in a reset state (S282). If this flag F is in the reset state, the timing operation of a timer T2 (not shown) that counts the duration of the paper feed error determination process is temporarily stopped (S284), and the elapsed time of the paper feed error error state is set. The timer T3 (not shown) for timing is started or restarted (S286), the flag F is set to the value “1” (S288), the process proceeds to S289, and conversely if the flag F is in the reset state, The process proceeds to S289 as it is.
[0066]
  In S289, it is determined whether the time measured by the timer T3 (elapsed time in the paper feed error state) has reached a preset determination time t3. If the determination time t3 has not been reached, the process proceeds to S260. On the contrary, if the determination time t3 has been reached, the processing of S290 and S300 is executed and the processing is terminated.
[0067]
  If it is determined in S270 that the estimated current i is greater than or equal to the second determination value ib, it is determined whether or not a paper feed error error determination flag F is set (S272). If the flag F is not set, the process proceeds to S280 as it is. If the flag F is set, the timer T3 temporarily stops counting the elapsed time of the paper feed error error state. (S274) The timer T2 starts or restarts the time keeping operation of the paper feed error error determination process (S276), resets the flag F (S278), and then proceeds to S280.
[0068]
  In this way, in the paper feed error determination process shown in FIG. 6, when the estimated current i becomes smaller than the second determination value ib and a paper feed error is determined, the timer T3 is used to make a paper feed error error state. The paper feed error error determination process is continued until the elapsed time reaches the determination time t3. When the elapsed time reaches the determination time t3, automatic recovery from the paper feed error is performed. Is determined to be difficult, and the processes of S290 and S300 are executed.
[0069]
  Therefore, according to this paper feed error determination process, even if a paper feed error is determined from the estimated current i, the paper feed roller 10 is continuously driven to automatically return from the paper feed error to the normal state. This makes it possible to restore and improve the reliability and usability of the sheet feeding device. [Modification 2]
  In the above embodiment, each error is determined using the estimated current i estimated by the state estimator OBS. However, as shown in FIG. When the current detector 41 as the current detecting means is incorporated in the error detecting section 160, each error can be detected even if the error detecting section 160 executes the error detecting process shown in FIG.
[0070]
  That is, in the error detection process shown in FIG. 8, first, the estimated current i is acquired from the state estimator OBS of the arithmetic processing unit 131, and the current actually flowing from the current detector 41 to the paper feed motor 20 (detected current). ) Is is acquired (S410).
  Then, the absolute value of the deviation between the acquired detected current is and the estimated current i is calculated as a current deviation Δi (S420), and the calculated current deviation Δi and a predetermined determination criterion value for error determination Δio is compared (S430).
[0071]
  If the current deviation Δi is larger than the determination reference value Δio (S430: YES), it is determined that some kind of error such as the above-mentioned no paper error, paper feed error, jam error has occurred. In order to stop the operation of the paper feed motor 20, an operation stop command is output to the interrupt processing unit 123 (S450), an error message is displayed on the display device 50 (S460), and the process ends.
[0072]
  If the current deviation Δi is equal to or smaller than the determination reference value Δio (S430: NO), it is determined that no error has occurred, the process proceeds to S440, and it is determined whether the paper feed is completed. To do. If the sheet feeding is not completed (S440: NO), the process proceeds to S410 again. Conversely, if the sheet feeding is completed (S440: YES), the process is terminated.
[0073]
  As described above, when the current detector 41 for detecting the current flowing through the paper feed motor 20 is provided, the current value (detected current) is detected by the current detector 41 and the state estimator OBS. The error state can also be detected by obtaining the deviation Δi from the estimated current i estimated in this way and comparing the current deviation Δi with the determination reference value Δio. [Modification 3]
  On the other hand, in the above-described embodiment and the first and second modifications, the error state is detected using the estimated current i estimated by the state estimator OBS. However, the error current is not necessarily detected by the estimated current i. The rotation angle (estimated angle) θ or the angular velocity (estimated angular velocity) ω of the paper feed roller 10 estimated by the state estimator OBS may be used.
[0074]
  When the estimated angle θ estimated by the state estimator OBS is used, error detection processing is executed according to the procedure shown in FIG. 9, and when the estimated angular velocity ω estimated by the state estimator OBS is used. The error detection process may be executed according to the procedure shown in FIG. Note that the error detection processing shown in FIGS. 9 and 10 is basically the same as the error detection processing shown in FIG. 8, and only the parameters used for error determination are different.
[0075]
  That is, in the error detection process shown in FIG. 9, the estimated angle θ is acquired from the state estimator OBS of the arithmetic processing unit 131 and the actual rotation angle (detection) of the paper feed roller 10 obtained based on the detection signal from the encoder 12 is detected. An angle) θs is acquired (S410 ′). Then, the absolute value of the deviation between the obtained detected angle θs and the estimated angle θ is calculated as an angle deviation Δθ (S420 ′), and the calculated angle deviation Δθ and a predetermined criterion for error determination are set. The value Δθo is compared (S430 ′).
[0076]
  When the angle deviation Δθ is larger than the determination reference value Δθo (S430 ′: YES), it is determined that some kind of error such as the above-described no-paper error, paper feed error, jam error has occurred. Then, after executing the processing of S450 and S460, the processing ends.
[0077]
  On the other hand, if the angle deviation Δθ is equal to or smaller than the determination reference value Δθo (S430 ′: NO), it is determined that no error has occurred, the process proceeds to S440, and whether or not the paper feed is completed. Determine whether. If the sheet feeding is not completed (S440: NO), the process proceeds to S410 again. If the sheet feeding is completed (S440: YES), the process is terminated.
[0078]
  Next, in the error detection process shown in FIG. 10, the estimated angular velocity ω is acquired from the state estimator OBS of the arithmetic processing unit 131 and the actual rotational angular velocity of the paper feed roller 10 obtained based on the detection signal from the encoder 12. (Detected angular velocity) ωs is acquired (S410 ″), and the absolute value of the deviation between the acquired detected angular velocity ωs and the estimated angular velocity ω is calculated as an angular velocity deviation Δω (S420 ″), and the calculated angular velocity deviation Δ ω is compared with a predetermined determination criterion value Δωo for error determination (S430 ″).
[0079]
  If the angular velocity deviation Δω is larger than the determination reference value Δωo (S430 ″: YES), it is determined that some kind of error such as the above-described no-paper error, paper feed error, or jam error has occurred. Then, after executing the processing of S450 and S460, the processing ends.
[0080]
  On the other hand, if the angular velocity deviation Δω is equal to or smaller than the determination reference value Δωo (S430 ″: NO), it is determined that no error has occurred, the process proceeds to S440, and whether or not the paper feed is completed. If the paper feed is not completed (S440: NO), the process proceeds to S410 again, and if the paper feed is completed (S440: YES), the process is terminated.
[0081]
  As described above, the sheet feeding device includes the encoder 12 that detects the rotation state of the sheet feeding roller 10 (and hence the sheet feeding motor 20), and the actual rotation angle of the sheet feeding roller 10 from the output of the encoder 12 is provided. Since θ and the rotational angular velocity ω can be obtained, the deviation between the detected value (detected angle θs, detected angular velocity ωs) and the estimated value (estimated angle θ, estimated angular velocity ω) estimated by the state estimator OBS is obtained. The error state can also be detected by comparing the deviation with the criterion value.
[0082]
  As described above, when the error state is detected from the deviation between the estimated value of the rotation angle θ or the rotation angular velocity ω of the paper feed roller 10 (or the paper feed motor 20) and the actual measurement value, the state estimator OBS Since the present invention can be applied to a system that does not estimate the current flowing through the paper feeding motor 20, it can be applied to, for example, a current control type paper feeding device that calculates the motor current as the control amount u in the arithmetic processing unit 131.
[0083]
  That is, in the current control type paper feeding device that calculates the motor current as the control amount u in the arithmetic processing unit 131, the motor current is not estimated by the state estimator OBS. Although error detection cannot be performed using the estimated current obtained by the state estimator OBS, the rotation angle θ or rotation of the paper feed roller 10 (or paper feed motor 20) is used for error detection as in the third modification. When the estimated value of the angular velocity ω is used, it is not necessary to estimate the motor current by the state estimator OBS, so that it can be directly applied to the current control type paper feeding device.
[0084]
  In the above description, the encoder 12 that detects the rotation amount of the paper feed roller 10 is used as the detection unit. However, an encoder that detects the rotation amount of the paper feed motor 20 is used as the detection unit. Alternatively, other sensors such as a potentiometer may be used.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating a schematic configuration of a sheet feeding device according to an embodiment.
FIG. 2 is a block diagram illustrating a configuration of a motor control system that drives the sheet feeding device according to the exemplary embodiment.
FIG. 3 is a block diagram illustrating a control system of an arithmetic processing unit according to the embodiment.
FIG. 4 is a flowchart illustrating a paper feed process executed by the CPU of the embodiment.
FIG. 5 is a flowchart illustrating an error detection process executed by an error detection unit according to the embodiment.
FIG. 6 is a flowchart illustrating a modified example of a paper feed error error determination process executed by an error detection unit.
FIG. 7 is a block diagram illustrating a modified example of a motor control system that drives the sheet feeding device according to the embodiment.
FIG. 8 is a flowchart showing an error detection process for performing error detection using an estimated current and a detected current.
FIG. 9 is a flowchart showing an error detection process for performing error detection using an estimated angle and a detected angle.
FIG. 10 is a flowchart showing an error detection process for performing error detection using an estimated angular velocity and a detected angular velocity.
FIG. 11 is an explanatory diagram illustrating the behavior of the sheet feeding device in a normal state.
FIG. 12 is an explanatory diagram illustrating the behavior of the sheet feeding device in an error state.
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 2 ... Paper mounting plate, 4 ... Paper, 6 ... Conveyance roller, 8 ... Supporting member, 9 ... Separation member, 10 ... Paper feed roller, 12 ... Encoder, 18 ... Registration sensor, 20 ... Paper feed motor, 20a ... Rotating shaft ,
DESCRIPTION OF SYMBOLS 40 ... Motor drive circuit, 41 ... Current detector, 50 ... Display apparatus, 56 ... Encoder, 100 ... Signal generation circuit, 110 ... Register group, 120 ... Paper feed state check part, 130 ... Control signal generation part, 131 ... Calculation Processing unit, ADD1 ... first adder, ADD2 ... second adder, INT ... integrator, MUL1 ... first gain integrator, MUL2 ... second gain integrator, OBS ... state estimator, 140 ... drive signal generator , 150... Clock generation unit, 160... Error detection unit.

Claims (2)

A paper feeding means for feeding paper by rotating a roller in contact with the paper using a DC motor;
Detecting means for detecting the amount of rotation of the DC motor or the roller;
A paper feeding device comprising:
Estimation means for estimating a state quantity (excluding the rotation quantity) representing the operating state of the paper feeding means based on the rotation amount detected by the detection means and the control amount input to the DC motor;
An error detecting means for detecting an error state of the paper feeding means by comparing the state quantity estimated by the estimating means and a preset determination condition during the paper feeding operation by the paper feeding means ;
The error detection means determines a paper-out error that there is no paper to be fed in a first period after the paper feeding operation is started by the paper feeding means, and in the second period after the first period, the roller the determined misfeeds error by idling, the rear second period of time, in the third period until the paper feeding operation by the paper feeding means is completed, characterized that you determine jam error as a paper jam state A paper feeder. Said error detection means, upon detecting an error condition, such as a driving state according to the result of said detection, supply of claim 1, wherein Rukoto a control means for controlling the paper feeding means Paper device.

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