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JP4520071B2 - Paper feeding device and image forming apparatus - Google Patents

Paper feeding device and image forming apparatus Download PDF

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Publication number
JP4520071B2
JP4520071B2 JP2001135095A JP2001135095A JP4520071B2 JP 4520071 B2 JP4520071 B2 JP 4520071B2 JP 2001135095 A JP2001135095 A JP 2001135095A JP 2001135095 A JP2001135095 A JP 2001135095A JP 4520071 B2 JP4520071 B2 JP 4520071B2
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paper
sheet
friction member
sheet feeding
feeding device
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JP2002326732A (en
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隆 宮城
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Tohoku Ricoh Co Ltd
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Tohoku Ricoh Co Ltd
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Description

【０００１】
【発明の属する技術分野】
本発明は、給紙装置およびこれを有する画像形成装置に関し、さらに詳しくは、用紙等のシート状記録媒体に対し補助分離機構を有する給紙装置における分離装置および画像形成装置に関する。
【０００２】
【従来の技術】
画像形成装置のうちの印刷装置の一例としての孔版印刷装置では、製版されたマスタ（以下、単に「マスタ」という）を巻装した版胴に対して、給紙装置から所定のタイミングで送られてくるシート状記録媒体としての用紙をプレスローラや圧胴等の押圧手段で押し付け、このときの押圧作用により版胴内部から供給されるインキをマスタの穿孔部分から滲み出させて用紙上に転移させることによって、印刷画像を用紙に形成するものである。
複写装置やプリンタ等では、給紙装置から所定のタイミングで送られてくる用紙に像担持体上に形成されたトナー像を転写手段により転写して画像を形成することが行われている。
【０００３】
印刷装置、複写装置、プリンタ等の画像形成装置に連結したり内蔵したりして使用される給紙装置では、昇降可能な給紙台（給紙トレイ）または給紙カセットに複数枚の用紙が積載・収容されており、その最上の用紙にピックアップローラを接触させて送り出すと共に、ピックアップローラにより複数枚重なった状態で送り出される用紙を分離部における給紙ローラおよび分離パッド（分離部材）との協働作用により１枚ずつ分離して送り出するようになっている。このような用紙の分離は、重なり合った用紙間の摩擦力よりも分離パッドと用紙間の摩擦力を大きくすることによって、下層の用紙は残されて最上の用紙だけが送り出されるもので、摩擦分離方式と呼ばれている。
取り分け印刷装置の中でも孔版印刷装置においては、多種多様な用紙が使用されている。一般に、用紙は、標準紙、薄紙、厚紙に分類されているが、さらに細かくは標準紙、更紙、薄紙、厚紙、特殊に分類することができる。このように細分類したものの具体的な用途例を挙げると以下のようである。すなわち、標準紙としては上質紙（上質５５ｋｇ紙、孔版上質紙等）、中質紙、再生紙等がある。薄紙としては薄手ののし紙や上質４５ｋｇ紙等があり、厚紙としては上質１３５ｋｇ以上の紙、画用紙、ハガキ等があり、特殊紙（以下、単に「特殊」というときがある）としては封筒（角形、長形）等がある。
【０００４】
このような給紙装置の分離部において、例えば特開昭５９−１２４６３３号公報で開示されているように、分離パッドの両脇に摩擦部材を設け、その摩擦部材を用紙の裏側に接触させることにより、用紙を略Ｕ字形に変形させて用紙分離を行う分離装置はすでに知られている（以下、「前者の技術」という）。
【０００５】
また、例えば特開２０００−２９６９３３号公報で開示されているように、分離パッド（捌き部材）の前方に設けた用紙ガイド部材において、給紙ローラの左右端部から所定の距離の所に摩擦部材を設け、前者の技術における前記分離装置と同様に用紙を略Ｕ字形に変形させて用紙分離のアシスト動作を行うようにした給紙装置も提案されている（以下、「後者の技術」という）。
【０００６】
【発明が解決しようとする課題】
しかしながら、前者の技術では、給紙される用紙にある程度の腰が無いと用紙の左右側縁部が持ち上げられるだけで、２枚目以降の用紙に対しては十分に分離力が作用しにくく、特に高温・高湿時などで用紙先端部にウエーブ（波打ち）が発生している場合は、その用紙先端部が分離パッド両脇の摩擦部材に十分に接触せずに分離力が作用しなくなって、複数枚の用紙を重なった状態で同時に給送する重送が発生する。これとは逆に、腰が強い厚紙等の用紙では、給紙負荷が大きくなるために不送りになりやすいという問題点がある。
【０００７】
後者の技術では、腰が強い厚紙や、用紙先端部に下方向のカールがあったり、波打ちがある用紙の通紙時においては、やはり不送りの発生や分離部でジャムになるという問題点がある。
【０００８】
したがって、本発明は、前記事情に鑑みてなされたものであって、用紙の厚さや腰の強弱に拘らず、また用紙先端部に発生したウエーブやカールの有無に拘らず用紙（シート状記録媒体）を確実に分離するための機構を備えた給紙装置および画像形成装置を提供することを目的とする。
【０００９】
【課題を解決するための手段】
本発明は、上述した課題を解決すると共に前記目的を達成するために、各請求項毎の発明においては以下のような特徴ある手段・構成を採っている。
請求項１記載の発明は、複数枚のシート状記録媒体が積載される昇降可能な給紙台と、該給紙台上のシート状記録媒体を最上のものから１枚ずつ捌いて順に給紙方向に送り出す給送分離部とを具備する給紙装置において、前記給紙方向と直交する幅方向において所定の間隔をもって設けられ前記給紙台上の最上のシート状記録媒体に接触してこれを給紙方向に送り出す２つの給紙部材と、前記各給紙部材に対向してその下方に配置され前記各給紙部材に向けて接触すべく押圧される２つの第１摩擦部材と、前記各第１摩擦部材を保持し、かつ、前記各給紙部材と前記各第１摩擦部材との接点よりも前記給紙方向の上流側において前記各給紙部材と非接触である位置でシート状記録媒体の先端部を前記各第１摩擦部材に案内するための形状を備えた第１保持部材と、前記各第１摩擦部材の前記幅方向の間に配設されていて、その基端側が前記接点近傍における前記上流側からその下流側までに至る前記各第１摩擦部材上の前記給紙方向の何れかの位置で交差する交差位置を占め、その自由端が前記接点よりも前記下流側に位置する下流位置を占め、かつ、前記交差位置と前記下流位置との間の部分が前記各給紙部材の前記幅方向の間で該給紙部材の外周面よりも該給紙部材の軸に近づく向きに突出して形成された第２摩擦部材と、第２摩擦部材の前記基端側を保持する第２保持部材とを有することを特徴とする。
ここで、第１摩擦部材の前記幅方向の寸法は、第１摩擦部材の摩擦抵抗（分離力）をシート状記録媒体に有効に働かせるという点から、前記各給紙部材における前記幅方向の寸法よりも大きく形成されていることが好ましい。
【００１０】
請求項２記載の発明は、請求項１記載の給紙装置において、第２摩擦部材の幅方向寸法は、前記各第１摩擦部材の前記幅方向の保持間隔よりも小さく形成されていることを特徴とする。
【００１１】
請求項３記載の発明は、請求項１または２記載の給紙装置において、第２摩擦部材は、前記給紙方向に細長い薄板状をなすことを特徴とする。
【００１２】
請求項４記載の発明は、請求項１、２または３記載の給紙装置において、第２摩擦部材は、弾性を有することを特徴とする。
ここで、「第２摩擦部材の有する弾性」とは、第２摩擦部材の前記突出した部分（前記交差位置と前記下流位置との間の部分）が、搬送されてきたシート状記録媒体と接触するときに弾性的に略下方に撓み変形し得る程度の弾性を意味するものであって、ひいては第２摩擦部材の摩擦抵抗（分離力）がシート状記録媒体に適度に作用して、シート状記録媒体を確実に分離する（捌く）ことができるようになることを意味するものである。
【００１３】
請求項５記載の発明は、請求項１ないし４の何れか一つに記載の給紙装置において、第２保持部材は、弾性を有することを特徴とする。
【００１４】
請求項６記載の発明は、請求項１、２または３記載の給紙装置において、第２摩擦部材は、実質的に剛体からなり、第２保持部材は、弾性を有することを特徴とする。
【００１５】
請求項５や６等において、「第２保持部材の有する弾性」とは、第２摩擦部材の前記突出した部分（前記交差位置と前記下流位置との間の部分）に、搬送されてきたシート状記録媒体と接触するときの押圧が加えられたときに、第２摩擦部材の前記押圧に連動して第２保持部材が適度に弾性的に変位し得る程度の弾性を意味するものであって、ひいては第２摩擦部材の摩擦抵抗（分離力）がシート状記録媒体に適度に作用して、シート状記録媒体を確実に分離する（捌く）ことができるようになることを意味するものである。
【００１６】
請求項７記載の発明は、請求項１ないし６の何れか一つに記載の給紙装置において、捌きにくいシート状記録媒体の場合、第２摩擦部材の前記交差位置は前記接点と一致する位置から前記接点より前記上流側までの何れかの位置にあり、捌きやすいシート状記録媒体または第２摩擦部材に接触すると給紙不良が発生しやすい場合、第２摩擦部材の前記交差位置は前記接点と一致する位置から前記接点より前記下流側までの何れかの位置にあることを特徴とする。
【００１７】
請求項８記載の発明は、請求項１ないし７の何れか一つに記載の給紙装置において、前記各給紙部材における前記下流側に配設され前記各給紙部材により送り出されたシート状記録媒体をさらに前記下流側に搬送する搬送部材と、前記各給紙部材により送り出されたシート状記録媒体を前記給紙方向に案内するための、前記下流側に延びた逃げを備えた案内部材とを有し、第２摩擦部材の前記自由端側は、前記案内部材における前記下流側の前記逃げの下方に潜り込んでおり、第２摩擦部材の前記自由端側は、略上下方向に変位可能であり、第２摩擦部材の前記自由端側の変位を前記案内部材の前記下流側で略上下方向に規制する変位規制手段を有することを特徴とする。
【００１８】
請求項９記載の発明は、請求項８記載の給紙装置において、前記変位規制手段は、第２摩擦部材の前記自由端側および前記案内部材の前記下流側の何れか一方に形成された凹部と、第２摩擦部材の前記自由端側および前記案内部材の前記下流側の何れか他方に形成され前記凹部に嵌入する凸部とを有することを特徴とする。
【００１９】
請求項１０記載の発明は、請求項１ないし９の何れか一つに記載の給紙装置において、前記交差位置と前記下流位置との間の第２摩擦部材の突出部分が前記各給紙部材と前記各第１摩擦部材とで形成されるシート状記録媒体の搬送面よりも下方になるように、第２保持部材を退避させる退避手段を有することを特徴とする。
請求項１０記載の給紙装置においては、前記退避手段を最も簡単な構成でかつ安価に構成するという点から、前記退避手段は、第２保持部材の上下方向に形成された溝と、この溝に嵌入して第２保持部材を前記上下方向に調整し保持する調整ネジとを有することが好ましい。
【００２０】
請求項１１記載の発明は、請求項１、２または３記載の給紙装置において、第２摩擦部材および第２保持部材は、共に実質的に剛体からなり、前記交差位置と前記下流位置との間の第２摩擦部材の突出部分が下方に変位するように、第２保持部材を自動的に変位させる変位手段を有することを特徴とする。
【００２１】
請求項１２記載の発明は、請求項４記載の給紙装置において、第２保持部材は、実質的に剛体からなり、前記交差位置と前記下流位置との間の第２摩擦部材の突出部分が下方に変位するように、第２保持部材を自動的に変位させる変位手段を有することを特徴とする。
ここで、請求項１１または１２記載の給紙装置において、前記変位手段を簡単な構成でかつ安価に構成するという点から、前記変位手段は、第２保持部材を略上下方向に案内する案内手段と、第２保持部材を略上方向に付勢する付勢手段とを有することことが好ましい。
また、請求項１ないし１２の何れか一つに記載の給紙装置において、各給紙部材を簡単な構成でかつ安価に構成するという点から、各給紙部材は、給紙ローラであることが好ましい。
【００２２】
請求項１３記載の発明は、請求項１ないし１２の何れか一つに記載の給紙装置において、前記各給紙部材は、給紙ローラであり、前記給送分離部は、前記給紙ローラ周りに揺動自在かつ給紙圧調整可能に支持され前記給紙台上の最上のシート状記録媒体に接触してピックするピックアップローラと、該ピックアップローラにより搬送されてきたシート状記録媒体を前記給紙方向に送り出す前記給紙ローラとを有することを特徴とする。
【００２３】
請求項１４記載の発明は、給送されてきたシート状記録媒体に画像形成を行う画像形成装置において、請求項１ないし１３の何れか一つに記載の給紙装置を有することを特徴とする。
【００２４】
【発明の実施の形態】
以下、図を参照して実施例を含む本発明の実施の形態（以下、「実施形態」という）を説明する。本発明の実施形態を適用する従来例および各実施形態等に亘り、同一の機能や形状等を有する部材や構成部品等の構成要素については、同一符号を付すことによりその説明を省略する。図および説明の簡明化を図るため、図に表されるべき構成要素であっても、その図において特別に説明する必要がない構成要素は適宜断わりなく省略することがある。
まず、図１０を参照して、本発明を適用するデジタル感熱式の感熱孔版印刷装置２００の概略的な全体構成と共に、その動作について簡単に説明する。感熱孔版印刷装置２００は、給送されてきたシート状記録媒体に画像形成としての印刷を行う画像形成装置のうちの印刷装置の一例である。
【００２５】
図１０において、符号１５０は、感熱孔版印刷装置２００の骨組みをなす装置本体フレームを示す。装置本体フレーム１５０の上部にある、符号８０で示す部分は原稿読取装置を構成し、その下方の符号９０で示す部分は製版給版装置、その左側に符号１００で示す部分は多孔性の印刷ドラム１０１が配置された印刷ドラム装置、その左の符号７０で示す部分は排版装置、製版給版装置９０の下方の符号１１０で示す部分は給紙装置、印刷ドラム１０１の下方の符号１２０で示す部分は印圧装置、装置本体フレーム１５０の左下方の符号１３０で示す部分は排紙装置を、それぞれ示している。
【００２６】
給紙装置１１０は、複数枚のシート状記録媒体としての用紙Ｐが積載される昇降可能な給紙台５１と、給紙台５１上の用紙Ｐを最上のものから１枚ずつ捌いて順に給紙方向Ｘ４に送り出す給送分離部１１５と、給送分離部１１５から送り出された用紙Ｐを所定のタイミングを取って印刷ドラム１０１と印圧装置１２０との間に給送する上下一対のレジストローラ５５ａ，５５ｂとから主に構成されている。給送分離部１１５は、後述するように、ピックアップローラ１１、給紙ローラ１１２および分離パッド１１３から主に構成されている。
【００２７】
先ず、原稿読取装置８０の上部に配置された原稿載置台（図示せず）に、印刷すべき画像を持った原稿６０を載置し、図示しない操作パネルに配設されている製版スタートキー（図示せず）を押す。この製版スタートキーの押下に伴い、先ず排版工程が実行される。すなわち、この状態においては、印刷ドラム装置１００における版胴とも呼ばれる印刷ドラム１０１の外周面に前回の印刷で使用された使用済マスタ６１ｂが装着されたまま残っている。
【００２８】
先ず、印刷ドラム１０１が反時計回り方向に回転し、印刷ドラム１０１外周面の使用済マスタ６１ｂの後端部が排版剥離ローラ対７１ａ，７１ｂに近づくと、同ローラ対７１ａ，７１ｂは回転しつつ一方の排版剥離ローラ７１ａで使用済マスタ６１ｂの後端部をすくい上げ、排版剥離ローラ対７１ａ，７１ｂの左方に配設された排版コロ対７３ａ，７３ｂと排版剥離ローラ対７１ａ，７１ｂとの間に掛け渡された排版搬送ベルト対７２ａ，７２ｂで矢印Ｘ１方向へ搬送されつつ排版ボックス７４内へ排出され、使用済マスタ６１ｂが印刷ドラム１０１の外周面から引き剥がされ排版工程が終了する。このとき印刷ドラム１０１は反時計回り方向への回転を続けている。剥離排出された使用済マスタ６１ｂは、その後、圧縮板７５により排版ボックス７４の内部で圧縮される。
【００２９】
排版工程と並行して、原稿読取装置８０では原稿読取が行われる。すなわち、図示しない原稿載置台に載置された原稿６０は、分離ローラ８１、前原稿搬送ローラ対８２ａ，８２ｂおよび後原稿搬送ローラ対８３ａ，８３ｂのそれぞれの回転により矢印Ｘ２からＸ３方向に搬送されつつ露光読み取りに供される。このとき、原稿６０が多数枚あるときは、分離ブレード８４の作用でその最下部の原稿のみが搬送される。原稿６０の画像読み取りは、コンタクトガラス８５上を搬送されつつ、蛍光灯８６により照明された原稿６０の表面からの反射光を、ミラー８７で反射させレンズ８８を通して、ＣＣＤ（電荷結合素子）からなる画像センサ８９に入射させることにより行われる。すなわち、原稿６０の読み取りは、公知の「縮小式の原稿読取方式」で行われ、その画像が読み取られた原稿６０は原稿トレイ８０Ａ上に排出される。画像センサ８９で光電変換された電気信号は、装置本体フレーム１５０内の図示しないアナログ／デジタル（Ａ／Ｄ）変換基板に入力されデジタル画像信号に変換される。
【００３０】
一方、この画像読み取り動作と並行して、デジタル信号化された画像情報に基づき製版および給版工程が行われる。すなわち、製版給版装置９０の所定部位にセットされたマスタ６１は、ロール状に巻かれたロール状態から引き出され、サーマルヘッド９１にマスタ６１を介して押圧しているプラテンローラ９２、および送りローラ対９３ａ，９３ｂの回転により搬送路の下流側に搬送される。このように搬送されるマスタ６１に対して、サーマルヘッド９１にライン状に並んだ複数個の微小な発熱素子とも呼ばれる発熱部が、Ａ／Ｄ変換基板（図示せず）から送られてくるデジタル画像信号に応じて各々選択的に発熱し、発熱した発熱部に接触しているマスタ６１の熱可塑性樹脂フィルムが溶融穿孔される。このように、画像情報に応じたマスタ６１の位置選択的な溶融穿孔により、画像情報が穿孔パターンとして書き込まれる。マスタ６１としては、多孔性支持体である和紙または合成繊維上に厚さ：１〜５μｍのポリエステル系の熱可塑性樹脂フィルムを貼り合わせたトータルの厚さ：１０〜４０μｍのものが、通常用いられる。
【００３１】
画像情報が書き込まれた製版済マスタ６１ａの先端は、給版ローラ対９４ａ，９４ｂにより印刷ドラム１０１の外周部側へ向かって送り出され、図示しないガイド部材により進行方向を下方へ変えられ、図示する給版位置状態にある印刷ドラム１０１の拡開したマスタクランパ１０２（仮想線で示す）へ向かって垂れ下がる。このとき印刷ドラム１０１は、排版工程により使用済マスタ６１ｂを既に除去されている。
【００３２】
そして、製版済マスタ６１ａの先端が、一定のタイミングでマスタクランパ１０２によりクランプされると、印刷ドラム１０１は図中Ａ１方向（時計回り方向）に回転しつつ外周面に製版済マスタ６１ａを徐々に巻きつけていく。製版済マスタ６１ａの後端部はカッタ９５により一定の長さに切断される。
【００３３】
一版の製版済マスタ６１ａが印刷ドラム１０１の外周面に巻装されると製版および給版工程が終了し、印刷工程が開始される。先ず、給紙装置１１０の給紙モータ３９が所定のタイミングで回転駆動されることによって、ピックアップローラ１１が時計回り方向に回転して給紙台５１上の最上の用紙Ｐをピック（拾い上げ・取り出）すると共に、ピックアップローラ１１により搬送されてきた用紙Ｐの最上の１枚が、給紙ローラ１１２および分離パッド１１３との協働作用により分離されてレジストローラ対５５ａ，５５ｂに向けて矢印Ｘ４方向である給紙方向Ｘ４に送り出される。さらに、レジストモータ４０が所定のタイミングで回転駆動されることにより、用紙Ｐの先端はレジストローラ対５５ａ，５５ｂの回転によって印刷ドラム装置１００における印刷ドラム１０１の回転と同期した所定のタイミングで印圧装置１２０に送られる。送り出された用紙Ｐが、印刷ドラム１０１と押圧手段としてのプレスローラ１０３との間にくると、印刷ドラム１０１の外周面下方に離間していたプレスローラ１０３が上方に移動されることにより、印刷ドラム１０１の外周面に巻装された製版済マスタ６１ａに押圧される。こうして、印刷ドラム１０１の多孔部分および製版済マスタ６１ａの穿孔パターン部分（共に図示せず）からインキが滲み出し、この滲み出たインキが用紙Ｐの表面に転移されて、印刷画像が形成される。
【００３４】
このとき、印刷ドラム１０１の内周側では、インキ供給管１０４からインキローラ１０５とドクターローラ１０６との間に形成されたインキ溜まり１０７にインキが供給され、印刷ドラム１０１の回転方向と同一方向に、かつ、印刷ドラム１０１の回転速度と同期して回転しながら内周面に転接するインキローラ１０５により、インキが印刷ドラム１０１の内周側に供給される。
【００３５】
印圧装置１２０において印刷画像が形成された用紙Ｐは、排紙剥離爪１１４により印刷ドラム１０１から剥がされ、吸着用ファン１１８に吸着されつつ、吸着排紙入口ローラ１１５および吸着排紙出口ローラ１１６に掛け渡された搬送ベルト１１７の反時計回り方向の回転により、矢印Ｘ５のように排紙装置１３０へ向かって搬送され、排紙台５２上に順次排出積載される。このようにして所謂版付け印刷とも呼ばれている試し刷りが終了する。
【００３６】
次に、前記操作パネルに配設されている図示しないテンキーで印刷枚数をセットし、図示しない印刷スタートキーを押下すると上記試し刷りと同様の工程で、給紙、印刷および排紙の各工程がセットした印刷枚数分繰り返して行われ、孔版印刷の全工程が終了する。
【００３７】
説明が前後するが、給紙分離部１１５の給紙手段（ピックアップローラ１１および給紙ローラ１１２）の駆動は、従来の給紙手段の駆動方式であるカムやセクタギヤ等を用いた方式に代えて、図３にも示されているように、印刷ドラム１０１を回転駆動する図示しないメインモータの回転駆動力とは独立した給紙モータ３９で回転駆動する給紙手段独立駆動方式を採用している。
レジストローラ対５５ａ，５５ｂの駆動は、従来の駆動方式であるカムやセクタギヤ方式に代えて、前記メインモータの回転駆動力とは独立したレジストモータ４０で回転されるレジストローラ独立駆動方式を採用している。
上述した各給紙手段独立駆動方式やレジストローラ独立駆動方式は、押圧手段として、搬送されてくる用紙Ｐの先端部を保持する保持手段（例えば用紙クランパ）を備え印刷ドラム１０１の外径と略同径の圧胴を採用した場合に顕著な効果を奏するものであることを付記しておく。それ故に、給紙分離部１１５の給紙手段（ピックアップローラ１１および給紙ローラ１１２）やレジストローラ対５５ａ，５５ｂの駆動は、従来の給紙手段の駆動方式であるカムやセクタギヤ等を用いた方式であっても勿論構わない。
（実施形態１）
図１ないし図７を参照して、実施形態１を説明する。
この実施形態１は、図１０に示した感熱孔版印刷装置２００と比較して、給紙装置１１０に代えて、図１等に示す給紙装置６０を有することのみ相違する。実施形態１の給紙装置６０は、図１０に示した給紙装置１１０と比較して、給送分離部１１５に代えて、給送分離部５０を有することが主に相違する。給送分離部５０は、給紙台５１上の用紙Ｐを最上のものから１枚ずつ捌いて（換言すれば１枚ずつ分離して）順に給紙方向Ｘ４に送り出す給紙手段としての構成・機能を有する。
【００３８】
給送分離部５０は、図１、図２および図６に示すように、後述する２つの給紙ローラ１２，１２の軸１２ｂの周りに揺動自在かつ給紙圧調整可能に支持され給紙台５１（図３参照）上の最上の用紙Ｐに接触してピックするピックアップローラ１１と、給紙方向Ｘ４と直交する用紙幅方向Ｙにおいて所定の間隔をもって設けられピックアップローラ１１により搬送されてきた用紙Ｐを給紙方向Ｘ４に送り出す２つの給紙部材としての給紙ローラ１２，１２と、各給紙ローラ１２，１２に対向してその下方に配置され各給紙ローラ１２，１２に向けて接触すべく押圧される２つの第１摩擦部材１，１と、各第１摩擦部材１，１を下側から保持し、かつ、各給紙ローラ１２，１２と各第１摩擦部材１，１との接点１５よりも給紙方向Ｘ４の上流側において各給紙ローラ１２，１２の外周面と非接触である位置で用紙Ｐの先端部を各第１摩擦部材１，１に案内するためのガイド形状８を備えた第１保持部材１４と、各給紙ローラ１２，１２の用紙幅方向Ｙの間に配設されていて、その基端側２ｂが接点１５よりも給紙方向Ｘ４の上流側の各第１摩擦部材１，１の上面で交差する交差位置１６−１を占め、その自由端２ｃが接点１５よりも給紙方向Ｘ４の下流側に位置する下流位置を占め、かつ、交差位置１６−１と下流位置（自由端２ｃ）との間の部分が各給紙ローラ１２，１２の用紙幅方向Ｙの間で該各給紙ローラ１２，１２の外周面よりも図２に示す軸１２ｂに近づく向きに突出して形成された第２摩擦部材２と、第２摩擦部材２の基端側２ｂをその下側から保持する第２保持部材５とから主に構成されている。
【００３９】
以下、給紙装置６０における給送分離部５０周りの構成を詳述する。
給紙台５１は、例えば実公平５−１８３４２号公報の第３図および第８図に示されている自動間欠上昇機構と同様の構成を備えた昇降機構を採用していて、複数枚の用紙Ｐを積載して昇降可能になされている。給紙台５１は、前記昇降機構により、積載された用紙Ｐの最上が常にピックアップローラ１１に所定の給紙圧（用紙Ｐが搬送可能な押圧力）をもって接触する給紙位置を占めるように昇降駆動制御される。
なお、給紙台５１の昇降機構は、前記したものに限定されず、例えば特開昭５９−１２４６３３号公報の第１図に示されているようなワイヤー等を用いた機構も用いられる。
【００４０】
給紙台５１には、図３に示すように、用紙サイズに応じて用紙Ｐの両側端を位置決め揃えるための一対のサイドフェンス５２ａ，５２ｂが用紙幅方向Ｙに移動自在に配設されている。
【００４１】
ピックアップローラ１１は、芯金１１ａと一体的に形成された軸１１ｂの周りに一体的に固着されていて、軸１１ｂと共に回転自在になされた周知のもの、あるいは軸１１ｂと芯金１１ａとの間にワンウェイクラッチ（図示せず）を設けて、非駆動時には軸１１ｂに対してフリーに回転するように支持したものである。ピックアップローラ１１の外周表面を含む外周部には、用紙Ｐと接触したときに容易にピックできるようにゴム等の軟質の高摩擦材料が用いられている。また、ピックアップローラ１１の外周表面部は、図１に詳しく示されているように、摩擦抵抗を増大するために正面視で略鋸刃状の突起が全周に形成されている。
各給紙ローラ１２，１２は、芯金１２ａと一体的に形成された軸１２ｂの周りに一体的に固着されていて、軸１２ｂと共に回転自在になされているか、あるいはピックアップローラ１１と同様の支持方法を取る場合もある。各給紙ローラ１２，１２は、図３および図６に詳しく示されているように、各給紙ローラ１２，１２の間に幅方向寸法Ｄを有する第２摩擦部材２を臨ませることができるように用紙幅方向Ｙにおいて所定の間隔をもって設けられている。各給紙ローラ１２，１２の外周表面を含む外周部には、ピックアップローラ１１と同様に用紙Ｐと接触したときにこれを容易に給紙方向Ｘ４に送り出すことができるようにゴム等の軟質の高摩擦材料が用いられている。また、各給紙ローラ１２，１２の外周表面部は、図１に詳しく示されているように、摩擦抵抗を増大するために正面視で略鋸刃状の突起が全周に形成されている。
ピックアップローラ１１および各給紙ローラ１２，１２の外周部に用いられている高摩擦材料としては、例えばエチレン・プロピレンゴム（ＥＰＤＭ）でＪＩＳ−ＡスケールでＨｓ２５〜３５のかたさの物が好ましく用いられる。
【００４２】
図１ないし図３を参照して、ピックアップローラ１１および各給紙ローラ１２，１２の給紙駆動手段３０周りの構成を説明する。
図２に示すように、各給紙ローラ１２，１２と軸１２ｂとの間およびピックアップローラ１１と軸１１ｂとの間には、ワンウェイクラッチ３１がそれぞれ介装されている。各給紙ローラ１２，１２の軸１２ｂには歯付きのプーリ３３が、ピックアップローラ１１の軸１１ｂには歯付きのプーリ３２がそれぞれ取り付けられている。プーリ３３およびプーリ３２には、タイミングベルト３４が掛け渡されていて、ピックアップローラ１１と各給紙ローラ１２，１２とはタイミングベルト３４および各ワンウェイクラッチ３１を介して駆動力伝達関係にある。各ワンウェイクラッチ３１のクラッチロック方向（回転駆動力の接続方向）は、ピックアップローラ１１と各給紙ローラ１２，１２とが用紙Ｐを分離して給送するために回転される図中矢印で示されている時計回り方向に設定されている。これにより、ピックアップローラ１１と各給紙ローラ１２，１２とは、時計回り方向のみに回転可能となっている。
【００４３】
ピックアップローラ１１の軸１１ｂおよび各給紙ローラ１２，１２の軸１２ｂは、図２および図３に示すように、共に転がり軸受２２を介して、下側に開口を有するコ字状をなす給紙アーム２１に回転自在に取り付けられている。ピックアップローラ１１は、各給紙ローラ１２，１２の軸１２ｂを中心として自重、給紙アーム２１の重さ、および給紙アーム２１の図２の左上端に取り付けられたバネ２４（引張バネ）の付勢力により、給紙アーム２１の自由端側と共に所定角度揺動自在になされていて、適度の給紙圧が付与されるようになっている。各給紙ローラ１２，１２の軸１２ｂは、図３に示すように、本体側板５９の外側に延び、転がり軸受２２を介して本体側板５９に回転自在に支持されている。本体側板５９の外側に延びた軸１２ｂの端部には、歯付きの駆動プーリ３６が固設されている。バネ２４は、その一端が給紙アーム２１の図２の左上端に、その他端が本体側板５９側に、それぞれ取り付けられている。
【００４４】
給紙モータ３９は、ステッピングモータからなり、各給紙ローラ１２，１２およびピックアップローラ１１を回転する給紙駆動手段としての機能を有する。給紙モータ３９は、本体側板５９にネジを介して取り付け固定されたモータブラケット３８に固設されている。給紙モータ３９の出力軸には、歯付きのモータプーリ３５が固設されている。駆動プーリ３６とモータプーリ３５との間には、タイミングベルト３７が掛け渡されていて、駆動力伝達関係にある。
【００４５】
ここで、説明の便宜上から給紙駆動手段３０の詳細な動作を説明しておく。給紙の場合には、給紙モータ３９を図３において時計回り方向に正転させることで、給紙モータ３９の回転駆動力が、モータプーリ３５から、タイミングベルト３７、駆動プーリ３６、軸１２ｂへと伝達され、次いでワンウェイクラッチ３１のクラッチロック作用によって各給紙ローラ１２，１２が時計回り方向に回転する。これと同時に、軸１２ｂからプーリ３３へ伝達された給紙モータ３９の回転駆動力が、タイミングベルト３４を介してプーリ３２、軸１１ｂへと伝達され、次いでワンウェイクラッチ３１のクラッチロック作用によってピックアップローラ１１が時計回り方向に回転する。これにより、各給紙ローラ１２，１２およびピックアップローラ１１が共に時計回り方向に回転し、給紙台５１上に積載された最上の用紙Ｐがレジストローラ対５５ａ，５５ｂに向けて給送されることとなる。
【００４６】
バネ２４取り付け側の給紙アーム２１の図２における左前端には、遮光板２５が給紙方向Ｘ４に突出して取り付けられている。遮光板２５近傍の本体側板５９側に配設された図示しない不動部材には、遮光板２５を選択的に挟む態様で給紙位置を検知するための給紙位置検知センサ２６が固設されている。給紙位置検知センサ２６は、透過型フォトセンサである。
【００４７】
バネ２４の上側には、バネ２４の付勢力（引張力）を調整することにより、ピックアップローラが給紙台５１上の最上の用紙Ｐに接触するときの給紙圧を調整するための図示しない給紙圧調整機構が配設されている。
前記給紙圧調整機構としては、例えば特開平７−１２５８５５号公報（特願平５−２７３９０５号）の図２および図５に示されている給紙圧調整機構（１５０）と同様の構成を具備している。
【００４８】
各第１摩擦部材１，１は、各給紙ローラ１２，１２における図６に示す用紙幅方向Ｙの幅寸法Ａよりも大きい幅寸法Ｂをもって形成されていて、矩形の板状をなしている。各第１摩擦部材１，１は、例えば用紙Ｐに対して高摩擦であるウレタンゴム（Ｕ）でできていて、ＪＩＳ−ＡスケールでＨｓ７０〜７５のかたさの物が好ましく用いられる。各第１摩擦部材１，１は、各給紙ローラ１２，１２の図６に示す用紙幅方向Ｙの寸法Ａよりも大きい幅寸法Ｂで形成されている。各第１摩擦部材１，１は、第１保持部材１４の上部に例えば接着剤塗布により固定・保持されている。
【００４９】
各第１摩擦部材１，１の用紙Ｐに対する摩擦係数は、用紙Ｐの種類にもよるが、標準紙等に対応した摩擦係数の高いものでμ＝１．２位の物から厚紙に対応したμ＝０．８位の物までが用いられる。
なお、各第１摩擦部材１，１の材料は、ウレタンゴム系のものに限らず、例えばエチレン・プロピレンゴム（ＥＰＤＭ）系の物等を用いてもよい。
【００５０】
第１保持部材１４は、実施例的に言えば、用紙Ｐとの接触による耐摩耗性を重視して、例えばポリカーボネート樹脂（ＰＣ）で一体的に成形されている。第１保持部材１４には、図１にのみ示すように、第２摩擦部材２および第２保持部材５を組み入れ・収納するためにくり抜かれたトンネル状の空洞部１４ａが形成されている。
第１保持部材１４には、図２、図４および図５に示すように、各第１摩擦部材１，１および第１保持部材１４を略上下方向に変位可能に案内するための、断面半円状の案内溝１４ｂ（紙面の奥側は省略されている）が紙面の手前側および奥側に形成されている。一方、本体側板５９側の前記不動部材には、各案内溝１４ｂと緩く係合する断面半円状の図示しない案内部材が設けられている。第１保持部材１４の各案内溝１４ｂおよび前記各案内部材により、第１保持部材１４および各第１摩擦部材１，１を略上下方向に変位可能に案内する案内手段が構成されている。
【００５１】
また、第１保持部材１４には、各第１摩擦部材１，１を各給紙ローラ１２，１２に接触する向き、すなわち略上方向に付勢する加圧手段としての加圧バネ（圧縮バネ）１７（紙面の奥側は省略されている）が紙面の手前側および奥側に設けられている。各加圧バネ１７の一端は、第１保持部材１４の内部において紙面の手前側および奥側に形成されたホルダ部（図示せず）に、その他端は本体側板５９側の前記不動部材に、それぞれ係止されている。
【００５２】
加圧バネ１７の下側には、加圧バネ１７の付勢力を調整する図示しない分離圧調整機構が設けられている。この分離圧調整機構としては、例えば特開２０００−２９６９３３号公報の図３に示されているように、バネ（４３）の下端を押し上げる押上桿（４５）および押上桿（４５）を上下動させるカム（４６）を備えた調整ダイヤル（４７）から構成される
ここで、各加圧バネ１７の付勢力により、各給紙ローラ１２，１２と各第１摩擦部材１，１とは押圧されて、給紙方向Ｘ４において所定の長さのニップ部を形成するが、上述した「接点１５」とは、前記ニップ部における給紙方向Ｘ４の上流端を指すものとする。
第１保持部材１４のガイド形状８は、用紙Ｐの先端部を各第１摩擦部材１，１に確実に案内すべく、その表面が滑らかで用紙Ｐの引っ掛かりやその搬送を阻害しないなだらかな形状となっている。
【００５３】
第２摩擦部材２は、例えば用紙Ｐに対して高摩擦でかつ弾性を有する材料であるウレタンゴム（Ｕ）でできていて、ＪＩＳ−ＡスケールでＨｓ７０〜８０のかたさの物が好ましく用いられる。第２摩擦部材２の材料は、ウレタンゴム系のものに限らず、例えばエチレン・プロピレンゴム（ＥＰＤＭ）系の物を用いてもよい。
第２摩擦部材２の用紙Ｐに対する摩擦係数は、用紙Ｐの種類にもよるが、標準紙等に対応した摩擦係数の高いものでμ＝１．２位の物から厚紙に対応したμ＝０．８位の物までが用いられる。
第２摩擦部材２は、図６に示す幅方向寸法Ｄを各第１摩擦部材１，１の用紙幅方向Ｙの保持間隔寸法Ｃよりも小さく形成されている。
【００５４】
後述するように第２摩擦部材２および各第１摩擦部材１，１の作用により、用紙Ｐが略逆Ｕ字形に矯正されたときに、用紙先端部において生じた波打ちによって用紙Ｐの前記略逆Ｕ字形が左右非対称になっても、第２摩擦部材２が図７に詳しく示されているように給紙方向Ｘ４に細長い薄板状をなしていて適度の弾性を有していることにより、給紙方向Ｘ４に沿って若干のねじれが可能であるので、第２摩擦部材２は、より用紙Ｐに追従することができる。
【００５５】
図１、図２および図４に示されている第２摩擦部材２の配置位置（図８では符号２−１で示す）は、後述する図８に示されている交差位置１６−１と同様の位置を占めるように配設されている。第２摩擦部材２の自由端２ｃ側は、略上下方向に弾性的に撓んで変位可能となっており、その自由端２ｃ側は後述するように用紙ガイド板１０の下方に潜り込むように配設されている。第２摩擦部材２の自由端２ｃ側には、凹部としての孔２ａが貫通形成されている。
【００５６】
図６に示されているように、各給紙ローラ１２，１２の幅寸法Ａ、各第１摩擦部材１，１の幅寸法Ｂ、各第１摩擦部材１，１の保持間隔寸法Ｃ、第２摩擦部材２の幅寸法Ｄの大小関係をまとめると、Ｂ＞Ａ、Ｃ＞Ｄという関係にある。第１保持部材１４の用紙幅方向Ｙの寸法は、２Ｂ＋Ｃ＋αであり、例えば用紙幅方向Ｙの寸法の比較的小さい用紙Ｐの代表例としてハガキを挙げた場合に、そのハガキの用紙幅方向Ｙの寸法よりは少し小さめに設定されている。図６において、符号１３は、各給紙ローラ１２，１２がその軸１２ｂから抜け出すのを規制する止め輪を示す。
【００５７】
また、各給紙ローラ１２，１２と最上の用紙Ｐとの間の摩擦抵抗（Ｆ１）と、最上の用紙Ｐとその直ぐ下の用紙Ｐとの間の摩擦抵抗（Ｆ２）と、第２摩擦部材２と接触している下側の用紙Ｐとの間の摩擦抵抗（Ｆ３）と、各第１摩擦部材１，１と接触している下側の用紙Ｐとの間の摩擦抵抗（Ｆ４）との摩擦抵抗（摩擦係数）の大小関係をまとめると、（Ｆ１）＞（Ｆ４）＞（Ｆ３）＞（Ｆ２）という関係にあり、最上の用紙Ｐとその直ぐ下の用紙Ｐとの間の摩擦抵抗（Ｆ２）が最も小さくなる（摩擦分離方式）。
【００５８】
各給紙ローラ１２，１２とレジストローラ対５５ａ、５５ｂとの間の搬送路には、図１等に示すように、各給紙ローラ１２，１２により送り出された用紙Ｐを給紙方向Ｘ４に案内する案内部材としての上下一対の用紙ガイド板１０，１０Ａが設けられている。各用紙ガイド板１０，１０Ａは、板金でできていて、本体側板５９側に取り付け固定されている。
上側の用紙ガイド板１０Ａは、レジストローラ対５５ａ、５５ｂのニップ部直前の部位に突き当たった用紙Ｐの先端部に上方に湾曲した適度のタワミを形成すべく、その上流側が上方に湾曲して形成されていて、その下流側が上側のレジストローラ５５ａに至る部位まで延在している。
【００５９】
下側の用紙ガイド板１０は、給紙方向Ｘ４の上流側において、給紙台５１上に積載された用紙Ｐの先端を突き当て揃えるための給紙前面壁１０ｅを形成すべく上下方向に延び、第１保持部材１４のガイド形状８の下方近傍で曲げられここを通って下側のレジストローラ５５ｂに至る部位まで略直線状に延在している。
用紙ガイド板１０には、図７にも示されているように、第２摩擦部材２の自由端２ｃを用紙ガイド板１０の下方に潜り込ませるための、給紙方向Ｘ４の下流側に延びた逃げとしての逃げ窓１０ａが形成されている。図１、図４および図７に示されている逃げ窓１０ａ近傍の用紙ガイド板１０左側の部分は、用紙ガイド板１０の平面部分に対して右側斜め下方に延びていて、下流側淵１０ｂを形成している。用紙ガイド板１０における給紙方向Ｘ４下流側の下流側淵１０ｂには、第２摩擦部材２の孔２ａに緩く嵌入する下方に向けて突出した凸部としての爪１０ｃが一体的に形成されている。
【００６０】
上述したように、第２摩擦部材２の自由端２ｃ側の変位を下側の用紙ガイド板１０の給紙方向Ｘ４下流側で略上下方向に規制する変位規制手段は、第２摩擦部材２側の孔２ａおよび用紙ガイド板１０側の爪１０ｃから構成されている。
なお、前記変位規制手段は、前記の組み合わせに限らず、例えば第２摩擦部材２の自由端２ｃ側において下方に向けて突出して一体的に形成された凸部としての爪（図示せず）と、用紙ガイド板１０における給紙方向Ｘ４下流側の下流側淵１０ｂにおいて第２摩擦部材２の前記爪を緩く嵌入すべく下方に向けて突出した凹部としての長孔を備えた筒状部材との組み合わせでもよい（請求項９参照）。
【００６１】
用紙ガイド板１０は、給紙方向Ｘ４の上流側において、給紙台５１上に積載された用紙Ｐの先端を突き当て揃えるための給紙前面壁１０ｅを形成すべく上下方向に延び、第１保持部材１４のガイド形状８の下方近傍で曲げられてここを通って下側のレジストローラ５５ｂに至る部位まで略直線状に延在している。
【００６２】
用紙ガイド板１０の給紙前面壁１０ｅ側には、図５のみに示すように、後述する調整ネジ９を調整・操作するための逃げ孔１０ｄが開けられている。また、用紙ガイド板１０の逃げ窓１０ａは、第１保持部材１４のガイド形状８および各第１摩擦部材１，１の部分を用紙ガイド板１０から上方に突出して臨ませるべく、前記したように給紙方向Ｘ４の下流側淵１０ｂから給紙方向Ｘ４の上流側に延びて形成されている。
【００６３】
第２保持部材５は、例えば適度の弾性を有する板バネまたはステンレススチール製の薄板でできている。第２保持部材５の一端部（図１、図２および図４等の上端部）は、第２摩擦部材２の基端側２ｂを例えば接着剤塗布によりその下側から保持・固定しており、第２保持部材５の他端部（図１、図２および図４等の下端部）は、図１、図２および図４等ではその図示が省略されているが、図５のみに詳しく示す退避手段１９によって上下方向に移動自在に保持できるようになされている。なお、図１、図２および図４等では、第２保持部材５の他端部が、第２摩擦部材２および第２保持部材５を図示の配置形状となるように保持・固定されている。
【００６４】
第２保持部材５の下端部側には、図５に詳しく示すように、上下方向に長く形成された溝としての長孔５ａが開けられている。一方、用紙ガイド板１０の逃げ孔１０ｄに対向した第２保持部材５の下端部側には、第２保持部材５の下端部を挟む態様で、取付部材６が図示しないネジで用紙ガイド板１０に締結・固定されている。取付部材６は、例えば板金でできていて、用紙ガイド板１０の逃げ孔１０ｄに対向した位置に調整ネジ９と螺合可能な雌ネジを切られている。調整ネジ９は、段付きネジである。
【００６５】
上述したとおり、図５においてそれぞれ実線で示す第２摩擦部材２および第２保持部材５を、各給紙ローラ１２，１２と各第１摩擦部材１，１とで形成される用紙Ｐの搬送面１８よりも図５においてそれぞれ二点鎖線で示すように下方に退避させる退避手段１９は、第２保持部材５の長孔５ａおよびこの長孔５ａに嵌入して第２保持部材５を上下方向に調整し保持する調整ネジ９とから主に構成されている。
【００６６】
図５において、用紙ガイド板１０の給紙前面壁１０ｅ側の逃げ孔１０ｄおよび第２保持部材５の長孔５ａから調整ネジ９を挿入し、重送や不送り等の給紙ミスが発生しないように、用紙Ｐの種類に応じて第２摩擦部材２の配置位置を適宜調整した上で、取付部材６の前記雌ネジに調整ネジ９を螺合させることで第２保持部材５の下端部を調整し固定・保持することができる。なお、用紙Ｐの種類に応じて、第２摩擦部材２の配置位置を調整する内容については、図８を参照して後述する。
【００６７】
レジストローラ対５５ａ，５５ｂは、各給紙ローラ１２，１２の配置位置よりも給紙方向Ｘ４の下流側に配設されていて、給送分離部５０の各給紙ローラ１２，１２から送り出された用紙Ｐをさらに下流側に搬送する搬送部材としての機能も有する。
【００６８】
次に、給紙装置６０の動作について、図１０を参照して説明した給版工程終了後の給紙工程（給紙動作）と相違する点を中心に詳述する。給紙動作は、図示しない制御装置からの指令の下に行われる。まず、給紙台５１上には用紙Ｐとして厚紙（画用紙やハガキ）や中質紙あるいは薄紙ほどではない比較的薄い用紙Ｐが積載されている場合の給紙動作について説明する。
【００６９】
先ず、前記した実公平５−１８３４２号公報の第３図および第８図に示されている自動間欠上昇機構（以下、「前記公報の上昇機構」という）と同様の昇降用の図示しない駆動モータ（前記公報の上昇機構では駆動モータ３０）が回転駆動されることにより、前記公報と同様の上昇機構（前記公報の上昇機構ではウオーム３１、ウオームホイール２８、ピニオン２９、ラック２４、ガイド板２５、ガイドピン２６、ガイド溝２７）が作動して、給紙台５１が上昇すると、給紙台５１上の最上の用紙Ｐがピックアップローラ１１に接触する。
【００７０】
これにより、図２に示されているピックアップローラ１１と給紙アーム２１の自由端側とは、各給紙ローラ１２，１２の軸１２ｂを中心として反時計回りに揺動・上昇され、これに伴い遮光板２５が給紙位置検知センサ２６の光路を閉じる。このとき、給紙位置検知センサ２６から出力された信号が前記制御装置に入力され、給紙台５１上の最上の用紙Ｐがピックアップローラ１１に接触して適度な給紙圧が付与され給紙可能な給紙位置に臨んだことが前記制御装置で判断されることにより、該制御装置から出力される指令信号に基づいて前記駆動モータの回転駆動が停止されて、給紙台５１の上昇が停止する。
【００７１】
次いで、前記制御装置からの指令により、給紙モータ３９が所定のタイミングで回転駆動されることによって、ピックアップローラ１１が時計回り方向に回転して給紙台５１上の最上の用紙Ｐをピック（拾い上げ・取り出し）して各給紙ローラ１２，１２に向けて搬送する。ピックアップローラ１１の用紙Ｐの前記ピック動作に伴って給紙台５１上の用紙Ｐが減ると、上述したように給紙台５１が上昇し、常に給紙台５１上の最上の用紙Ｐが給紙位置を占めるように昇降制御される。
【００７２】
ピックアップローラ１１によってピックされた最上の用紙Ｐは、図４に示すように、その下の何枚かの用紙Ｐと重なるようにして搬送され、それぞれの先端Ｐａが第１保持部材１４のガイド形状８に接触・案内されつつ搬送される。このとき、ガイド形状８が用紙Ｐの進行方向に対して上方に傾斜していてなだらかな曲面を有するため、各用紙Ｐは最上の用紙Ｐの先端Ｐａから順に先行するように搬送される。先行した最上の用紙Ｐの先端Ｐａは、先ずピックアップローラ１１の回転と同時に時計回り方向に回転している各給紙ローラ１２，１２に接触し、これに前後して交差位置１６−１を占めている第２摩擦部材２と接触する。
この際、最上の用紙Ｐおよびその下の用紙Ｐの複数枚が一緒に、各給紙ローラ１２，１２と第２摩擦部材２の間、および各給紙ローラ１２，１２と各第１摩擦部材１，１との間のニップに進入しても、複数枚の用紙Ｐが第２摩擦部材２の幅方向Ｙの両側において各第１摩擦部材１，１と各給紙ローラ１２，１２とのニップで押えられていることにより、各給紙ローラ１２，１２と各第１摩擦部材１，１との協働作用による最上の用紙Ｐおよびその下の用紙Ｐの分離に加えて、比較的薄い用紙Ｐに対しても第２摩擦部材２の摩擦抵抗（分離力）が有効に働くので、確実な分離が行える。
このとき、腰の強い厚紙等の用紙Ｐに対しては、共に適度な弾性を有する第２摩擦部材２および第２保持部材５は、図４に二点鎖線で示すように下方に撓むように弾性的に変形することにより、用紙Ｐに無理な力が働かないので、不送りが発生しにくくなる。
【００７３】
こうして、各給紙ローラ１２，１２の送り力が最上の用紙Ｐのみに大きく与えられ、かつ、第２摩擦部材２および各第１摩擦部材１，１の各摩擦抵抗により、最上の用紙Ｐとその下の用紙Ｐとの間の摩擦抵抗が減少されたことにより、最上の用紙Ｐの１枚だけが下の用紙Ｐから分離され捌かれてレジストローラ対５５ａ，５５ｂに向けて給紙方向Ｘ４に送り出される。これ以降の動作は、図１０を参照して上述したと同様に行われるためその説明を省略する。
【００７４】
次に、給紙台５１上には用紙Ｐとして例えば薄紙（上質４５ｋｇ等）が積載されている場合の給紙動作を説明する。
用紙Ｐとして薄紙を使用する場合は、用紙Ｐ（薄紙）への第２摩擦部材２の摩擦抵抗を小さくして用紙Ｐのシワや破れ発生を防止する上から、前記製版スタートキーを押下する前に、図５に示した退避手段１９を操作する。
【００７５】
すなわち、図５に示されている退避手段１９の調整ネジ９を緩めて、同図において実線で示されている第２摩擦部材２および第２保持部材５の配置位置から、同図に二点鎖線線で示されている第２摩擦部材２’および第２保持部材５’の配置位置となるように、すなわち交差位置１６−１と自由端２ｃ’との間の第２摩擦部材２’の逆Ｕ字形の突出部分が各給紙ローラ１２，１２と各第１摩擦部材１，１とで形成される用紙Ｐの搬送面１８よりも下方になるように、第２保持部材５’の長孔５ａに対する調整ネジ９の締結位置を調整して、同ネジ９を取付部材６に締め付けて第２保持部材５を取付部材６に固定する。
【００７６】
この後、前記製版スタートキーを押下すると、上述したと同様に図示しない前記駆動モータが回転駆動されてから、図５では省略されているピックアップローラ１１が最上の用紙Ｐをピックして、最上の用紙Ｐが第１保持部材１４のガイド形状８に接触・案内されつつ搬送されるまでは、上述したと同様に行われる。
各用紙Ｐは最上の用紙Ｐの先端Ｐａから順に先行するように搬送されると共に、図５に二点鎖線で示されているように第２摩擦部材２’の逆Ｕ字形の突出部分が用紙Ｐの搬送面１８よりも下方に位置するので、用紙Ｐの裏面が第２摩擦部材２’に接触することがない。先行した最上の用紙Ｐの先端Ｐａは、ピックアップローラ１１の回転と同時に時計回り方向に回転している各給紙ローラ１２，１２に接触し、これに前後して各第１摩擦部材１，１と接触する。
【００７７】
この際、最上の用紙Ｐおよびその下の用紙Ｐの複数枚が一緒に、各給紙ローラ１２，１２と各第１摩擦部材１，１との間のニップに進入しても、複数枚の用紙Ｐが第２摩擦部材２の幅方向Ｙの両側において各第１摩擦部材１，１と各給紙ローラ１２，１２とのニップで押えられることにより、各第１摩擦部材１，１の摩擦抵抗（分離力）のみが有効に働くので、各給紙ローラ１２，１２と各第１摩擦部材１，１との協働作用により最上の用紙Ｐおよびその下の用紙Ｐの分離が確実に行える。
【００７８】
したがって、実施形態１の給紙装置６０によれば、従来の給紙装置のように給紙される用紙Ｐの腰が比較的弱い薄い用紙Ｐであっても、また２枚目以降の用紙Ｐに対しても、第２摩擦部材２による分離力（摩擦抵抗）が有効に働くと共に、連続的に、各第１摩擦部材１，１による分離力が作用するので、重送や不送りの発生によってジャム等の給紙不良を未然に防止することができる。
【００７９】
特に高温・高湿時などで用紙Ｐ先端部にウエーブ（波打ち）が発生していて左右非対称になっている場合でも、第２摩擦部材２が給紙方向Ｘ４に長く形成されていて若干のねじれが可能であるので、より用紙Ｐに追従してその分離力を作用させることができる。
また、用紙Ｐが腰の強い厚紙であっても、第２摩擦部材２と共に第２保持部材５が用紙Ｐの搬送面１８側に弾性的に撓むので、用紙Ｐに無理な力が働かず不送りが発生しにくくなる。
また、退避手段１９を操作することにより、かなりの薄紙に対して、第２摩擦部材２の摩擦抵抗を小さくすることが可能となるため、用紙Ｐのシワや破れを無くすことができる。
また、前記変位規制手段を有することにより、仮に、各給紙ローラ１２，１２とこの下流側のレジストローラ対５５ａ，５５ｂとの間の給紙路でジャムが発生した場合に、各給紙ローラ１２，１２側にそのジャムした用紙Ｐを引き出すときに、そのジャムした用紙Ｐと共に第２摩擦部材２が引っ張り出されることがないので、ジャム処理時の操作性が向上すると共に、第２摩擦部材２に対して損傷を与えたりすることもない。
【００８０】
従来の給紙装置１１０を搭載した感熱孔版印刷装置２００と、上述した本発明を適用した給紙装置６０を搭載した感熱孔版印刷装置とについて、重送において特に不安定であった用紙Ｐ、すなわち中質紙および更紙を使用して実際に給紙を行う実験（それぞれ用紙サイズＡ４の用紙Ｐで１０００枚の通紙実験）をし、その給紙評価を行った結果を下表１に示す。
従来の給紙装置１１０を搭載した感熱孔版印刷装置２００としては、株式会社リコー製のＶＴ１２２０を使用し、本発明を適用した給紙装置６０を搭載した感熱孔版印刷装置は、前記ＶＴ１２２０の給紙装置１１０に代えて、給紙装置６０を搭載したことのみ相違する。
各第１摩擦部材１，１としては、ウレタンゴム（Ｕ）製で、ＪＩＳ−ＡスケールでＨｓ７０のかたさの物を用いた。第２摩擦部材２としては、ウレタンゴム（Ｕ）製で、ＪＩＳ−ＡスケールでＨｓ７０のかたさの物を用いた。
【００８１】
【表１】

Figure 0004520071
【００８２】
表１から直ちに分かるように、本発明を適用した給紙装置６０での給紙結果は、中質紙および更紙の両方の用紙Ｐで重送発生が全くなく良好な通紙結果を得られた。これに対して、従来の給紙装置１１０では、中質紙通紙時に重送が多く発生し、また更紙通紙時においても重送が時々発生するというように、本発明を適用した給紙装置６０と比較して明確な有意差があった。
【００８３】
上述した技術事項から、図８を参照して直ちに以下のことが言える。
すなわち、捌き（分離し）にくい用紙Ｐを使用する場合には、第２摩擦部材２の配置位置２−２，２−１は、その交差位置が接点１５と一致する交差位置１６−２から接点１５より各第１摩擦部材１，１の上流側までの何れかの交差位置１６−１にあればよい。また、捌き（分離し）やすい用紙Ｐまたは第２摩擦部材２に接触すると給紙不良が発生しやすい用紙Ｐを使用する場合には、第２摩擦部材２の配置位置２−２，２−３は、その交差位置が接点１５と一致する交差位置１６−２から接点１５より各第１摩擦部材１，１の下流側までの何れかの交差位置１６−３にあればよい（請求項７参照）。
【００８４】
図８および上述した技術事項から、第２摩擦部材２の配置位置２−１，２−２，２−３は、その交差位置１６−１，１６−２，１６−３に表されているように、用紙Ｐの先端部と接触するタイミングを給紙方向Ｘ４で変えていると共に、第２摩擦部材２の摩擦抵抗が用紙Ｐの先端部の裏面に対して有効に働く範囲・大きさも変えているとみることができる。すなわち、第２摩擦部材２は、その配置位置２−１，２−２，２−３を変えることにより、各第１摩擦部材１，１により用紙Ｐの先端部の裏面に作用する摩擦抵抗に加えて、その摩擦抵抗の作用する時機および大きさを調節して第２摩擦部材２の摩擦抵抗を用紙Ｐの先端部の裏面に作用させることができるものである。
（実施形態１の変形例１）
実施形態１の変形例１は、実施形態１と比較して、適度の弾性を有する第２摩擦部材２に代えて、第２摩擦部材２を実質的に剛体で構成したことのみが相違する。（請求項６参照）。
【００８５】
第２摩擦部材２は、例えば如何なる腰の強い用紙Ｐとの接触によっても変形しない程度の剛性を有する変形しにくい材料、例えば第２保持部材５のそれよりも板厚の比較的厚いステンレススチールの板や板金材であってもよく、すなわち実質的に剛体であればよい。そして、適度の摩擦抵抗を与えるために、ステンレススチールの板や板金材で形成された第２摩擦部材２の用紙Ｐとの接触する上面に、格子目状の凹凸模様を一体的に形成したり、あるいは適度の摩擦抵抗を有するかたさの高いウレタンゴム等の別体を適宜の接着剤等により貼着してもよい。
第２摩擦部材２の基端側は、第２保持部材５によってその下側から例えば溶接や植え込みネジによって固定・保持されている。第２保持部材５は、実施形態１と同様に、弾性を有する板バネまたはステンレススチール製の薄板で形成してもよいが、用紙Ｐに対する第２摩擦部材２の摩擦抵抗を図４に示したと略同様にするためには、第２保持部材５の弾性力および形状を適宜調整する必要のあることを付記しておく。
（実施形態１の変形例２）
図９に、実施形態１の変形例２における給紙装置６０Ａの給送分離部５０Ａを示す。
変形例２の給送分離部５０Ａは、実施形態１の給送分離部５０と比較して、適度の弾性を有する第２摩擦部材２に代えて、実質的に剛体で構成した第２摩擦部材２Ａを有すること、適度の弾性を有する第２保持部材５に代えて、実質的に剛体で構成した第２保持部材５Ａを有すること、および交差位置１６−１と下流位置（自由端２Ａｃ）との間の第２摩擦部材２Ａの突出部分が下方に変位するように、第２保持部材５Ａを自動的に変位させる変位手段４９を有することが主に相違する（請求項１１参照）。
【００８６】
第２摩擦部材２Ａは、変形例１と同様に、例えば如何なる腰の強い用紙Ｐとの接触によっても変形しない程度の剛性を有する変形しにくい材料、例えば実施形態１の第２保持部材５のそれよりも板厚の比較的厚いステンレススチールの板や板金材であってもよく、すなわち実質的に剛体であればよい。そして、適度の摩擦抵抗を与えるために、第２摩擦部材２Ａの用紙Ｐとの接触する上面に、格子目状の凹凸模様を一体的に形成したり、あるいは適度の摩擦抵抗を有するかたさの高いウレタンゴム等の別体を適宜の接着剤等により貼着してもよい。
第２保持部材５Ａは、第２摩擦部材２Ａの下方の変位によって変形しない程度の、例えば実施形態１の第２保持部材５のそれよりも板厚の比較的厚いステンレススチールの板や板金材であってもよく、すなわち実質的に剛体であればよい。第２摩擦部材２Ａの基端側は、第２保持部材５Ａによってその下側から例えば溶接や植え込みネジによって固定・保持されている。
【００８７】
変位手段４９は、第２保持部材５Ａの基端側を略上下方向に案内する案内手段としてのスライドホルダ４６と、第２保持部材５Ａを略上方向に付勢する付勢手段としてのバネ４７（圧縮バネ）とから主に構成されている。第２保持部材５Ａの基端側は、断面矩形状をなすスライド部材４５が形成されている。スライド部材４５は、摺動による抵抗が小さく、かつ、耐久性のある例えばポリカーボネート樹脂（ＰＣ）やポリアミド樹脂（ＰＡ）で、第２保持部材５Ａの基端側と一体的にインサート成形されている。スライドホルダ４６も、同様の理由からスライド部材４５と同様の樹脂を選択して使用している。
【００８８】
次に、給紙装置６０Ａの動作について、実施形態１と相違する点を中心に詳述する。
先ず、実施形態１と同様に図示しない前記駆動モータが回転駆動されてから、図９では省略されているピックアップローラ１１が最上の用紙Ｐをピックして、最上の用紙Ｐが第１保持部材１４のガイド形状８に接触・案内されつつ搬送されるまでは、実施形態１と同様に行われる。
【００８９】
先行した最上の用紙Ｐの先端Ｐａは、各給紙ローラ１２，１２に接触し、これに前後して交差位置１６−１を占めている第２摩擦部材２と接触する。
この際、最上の用紙Ｐおよびその下の用紙Ｐの複数枚が一緒に、各給紙ローラ１２，１２と第２摩擦部材２の間、および各給紙ローラ１２，１２と各第１摩擦部材１，１との間のニップに進入しても、複数枚の用紙Ｐが第２摩擦部材２の幅方向Ｙの両側において各第１摩擦部材１，１と各給紙ローラ１２，１２とのニップで押えられていることにより、各給紙ローラ１２，１２と各第１摩擦部材１，１との協働作用による最上の用紙Ｐおよびその下の用紙Ｐの分離に加えて、比較的薄い用紙Ｐに対しても第２摩擦部材２の摩擦抵抗（分離力）が有効に働くので、確実な分離が行える。
このとき、腰の強い厚紙等の用紙Ｐに対しては、図９に二点鎖線で示すように、第２摩擦部材２Ａ’および第２保持部材５Ａ’は、スライド部材４５がスライドホルダ４６に滑らかに案内されながらバネ４７の付勢力に抗して、全体的に下方に変位する。これにより、用紙Ｐに無理な力が働かないので、各給紙ローラ１２，１２による用紙Ｐの送り出し時の不送り等の障害とならない。図９に二点鎖線で示す第２摩擦部材２Ａ’および第２保持部材５Ａ’の下方への全体的な変位の大小は、用紙Ｐの種類に応じて、すなわち主として用紙Ｐの腰の強弱の程度に応じて異なるものである。なお、変位手段４９の配置位置は、図示の簡明化を図るために用紙ガイド板１０の給紙前面壁１０ｅ側に固定して配置したが、第２摩擦部材２Ａ’および第２保持部材５Ａ’が下方へスムーズに変位するように、加圧バネ１７と同様の位置に配設した方がよいことを付記しておく。
【００９０】
上述したように、各給紙ローラ１２，１２の送り力が最上の用紙Ｐのみに大きく与えられ、かつ、第２摩擦部材２Ａおよび各第１摩擦部材１，１の各摩擦抵抗により、最上の用紙Ｐとその下の用紙Ｐとの間の摩擦抵抗が減少されたことにより、最上の用紙Ｐの１枚だけが下の用紙Ｐから分離され捌かれてレジストローラ対５５ａ，５５ｂに向けて給紙方向Ｘ４に送り出される。これ以降の動作は、上述したと同様に行われるためその説明を省略する。
したがって、変形例２によれば、実施形態１の退避手段１９を有することによる利点を除き、実施形態１と略同様の利点を得ることができる。
（実施形態１の変形例３）
実施形態１の変形例３は、変形例２における給紙装置６０Ａの給送分離部５０Ａと比較して、実質的に剛体で構成した第２摩擦部材２Ａに代えて、実施形態１と同様に適度の弾性を有する第２摩擦部材２を有することが主に相違する（請求項１２参照）。
【００９１】
変形例３の給紙動作は、変形例３における図９に二点鎖線で示した第２摩擦部材２Ａ’および第２保持部材５Ａ’の下方への変位と比較して、第２摩擦部材２が実施形態１と同様に弾性的な変形を受けながら、第２保持部材５Ａ’と共に下方へ変位することのみが相違する。したがって、変形例３によれば、変形例２と略同様の利点を得ることができる。
【００９２】
なお、本発明の実施形態は、上述したものに限らず、実施形態１等のピックアップローラ１１を設けたことによる後述する効果をそれ程望まなくてもよいのであれば、例えば実施形態１のピックアップローラ１１を除去しこれに代えて、給紙ローラ１２，１２を給紙台５１上の最上の用紙Ｐに接触してこれを給紙方向Ｘ４に送り出すように配置した２つの給紙部材としての給紙ローラ１２，１２を具備するものであってもよい（請求項１と請求項１３とを比較参照）。
また、各第１摩擦部材は、図７等に示した矩形パッド状の各第１摩擦部材１，１に限らず、例えば２つの分離ローラであってもよい。
【００９３】
以上述べたとおり、本発明を実施例を含む特定の実施形態や変形例等について説明したが、本発明の構成は、上述した実施形態や変形例等に限定されるものではなく、これらを適宜組み合わせて構成してもよく、本発明の範囲内において、その必要性および目的・用途等に応じて種々の実施形態や実施例を構成し得ることは当業者ならば明らかである。
例えば、用紙Ｐの種類や給紙・印刷条件に応じて、第２摩擦部材２を例えば図８に示した各配置位置とするために、略上下方向および／または給紙方向Ｘ４の上流側ないし下流側に自動的に移動・変位させるように制御したり、これに加えて、例えば特開２０００−２４７４６７号公報に開示されているような技術とを組み合わせて適用するようなこと、あるいは実施形態１等における各第１摩擦部材１，１の配置位置に代えて、１つの第１摩擦部材１の両脇に２つの第２摩擦部材２，２を配設するようなことは、本発明から直接的かつ容易に想到できる技術的事項に過ぎない。
【００９４】
【発明の効果】
以上述べたように、本発明によれば、上述したような従来装置の有する諸問題点を解決して新規な給紙装置および画像形成装置を提供することができる。請求項毎の効果を挙げれば次のとおりである。
請求項１ないし３記載の発明によれば、前記構成により、給紙台上の最上のシート状記録媒体が複数枚給送分離部のニップに進入しても、シート状記録媒体が第２摩擦部材の幅方向の両側において第１摩擦部材と給紙部材とに押えられていることにより、比較的薄いシート状記録媒体に対しても第２摩擦部材の分離力（摩擦抵抗）が有効に働くので、確実な分離が行える。
シート状記録媒体の種類によっては、各第１摩擦部材の各給紙部材への押し付け力（摩擦抵抗）を弱くして、第２摩擦部材によってシート状記録媒体の先端部を若干逆Ｕ字形にした方が給紙ミスが少ない場合があるが、このような調整も可能となる。
例えば、特に高温・高湿時などでシート状記録媒体先端部にウエーブ（波打ち）が発生していて左右非対称になっている場合でも、第２摩擦部材が例えば給紙方向に細長い薄板状をなしていることにより若干のねじれが可能であるので、よりシート状記録媒体に追従してその分離力を作用させることができる。
【００９５】
請求項４記載の発明によれば、第２摩擦部材は、弾性を有することにより、シート状記録媒体が例えば腰の強い厚紙であっても、第２摩擦部材が各給紙部材と各第１摩擦部材とで形成されるシート状記録媒体の搬送面側に弾性的に撓むので、請求項１、２または３記載の発明の効果に加えて、シート状記録媒体に無理な力が働かず不送りが発生しにくくなる。
【００９６】
請求項５記載の発明によれば、第２保持部材は、弾性を有することにより、シート状記録媒体が例えば腰の強い厚紙であっても、第２摩擦部材の基端側を保持している第２保持部材が各給紙部材と各第１摩擦部材とで形成されるシート状記録媒体の搬送面側に弾性的に撓むので、請求項１ないし４の何れか一つに記載の発明の効果に加えて、シート状記録媒体に無理な力が働かず不送りが発生しにくくなる。
【００９７】
請求項６記載の発明によれば、第２摩擦部材は、実質的に剛体からなり、第２保持部材は、弾性を有することにより、シート状記録媒体が例えば腰の強い厚紙であっても、第２摩擦部材の基端側を保持している第２保持部材が各給紙部材と各第１摩擦部材とで形成されるシート状記録媒体の搬送面側に弾性的に撓むので、請求項１、２または３記載の発明の効果に加えて、シート状記録媒体に無理な力が働かず不送りが発生しにくくなる。
【００９８】
請求項７記載の発明によれば、捌きにくいシート状記録媒体の場合、第２摩擦部材の交差位置は接点と一致する位置から接点より上流側までの何れかの位置にあり、捌きやすいシート状記録媒体または第２摩擦部材に接触すると給紙不良が発生しやすい場合、第２摩擦部材の交差位置は接点と一致する位置から接点より下流側までの何れかの位置にあることにより、請求項１ないし６の何れか一つに記載の発明の効果に加えて、シート状記録媒体の性状に応じて、第２摩擦部材を適切に配置することが可能となる。
【００９９】
請求項８記載の発明によれば、第２摩擦部材の自由端側は、案内部材における下流側の逃げの下方に潜り込んでおり、変位規制手段により、第２摩擦部材の自由端側の変位が案内部材の下流側で略上下方向に規制されているので、請求項１ないし７の何れか一つに記載の発明の効果に加えて、仮に、各給紙部材とこの下流側の搬送部材との間でジャムが発生した場合に、各給紙部材側にそのジャムしたシート状記録媒体を引き出すときに、そのジャムしたシート状記録媒体と共に第２摩擦部材が引っ張り出されることがないので、ジャム処理時の操作性が向上すると共に、第２摩擦部材に対して損傷を与えたりすることもない。
【０１００】
請求項９記載の発明によれば、変位規制手段は、第２摩擦部材の自由端側および案内部材の下流側の何れか一方に形成された凹部と、第２摩擦部材の自由端側および案内部材の下流側の何れか他方に形成され凹部に嵌入する凸部とを有することにより、請求項８記載の発明の効果に加えて、変位規制手段を簡単な構成でかつ安価にできる。
【０１０１】
請求項１０記載の発明によれば、交差位置と下流位置との間の第２摩擦部材の突出部分が各給紙部材と各第１摩擦部材とで形成されるシート状記録媒体の搬送面よりも下方になるように、第２保持部材を退避させる退避手段を有することにより、請求項１ないし９の何れか一つに記載の発明の効果に加えて、退避手段を操作することにより、かなりの薄紙に対して、第２摩擦部材の摩擦抵抗を小さくすることが可能となるため、シート状記録媒体のシワや破れを無くすことができる。
【０１０２】
請求項１１記載の発明によれば、第２摩擦部材および第２保持部材は、共に実質的に剛体からなり、変位手段により、例えば主としてシート状記録媒体の腰の強弱に応じて、交差位置と下流位置との間の第２摩擦部材の突出部分が下方に変位するので、請求項１、２または３記載の発明の効果に加えて、シート状記録媒体に無理な力が働かず不送りが発生しにくくなる。
【０１０３】
請求項１２記載の発明によれば、第２保持部材は、実質的に剛体からなり、変位手段により、例えば主としてシート状記録媒体の腰の強弱に応じて、交差位置と下流位置との間の第２摩擦部材の突出部分が下方に変位するので、請求項４記載の発明の効果に加えて、シート状記録媒体に無理な力が働かず不送りが発生しにくくなる。
【０１０４】
請求項１３記載の発明によれば、請求項１ないし１２の何れか一つに記載の発明の効果に加えて、ピックアップローラにより、給紙台上の最上のシート状記録媒体がピックされて各第１摩擦部材に搬送されると共に、第２摩擦部材の摩擦抵抗に対する各給紙ローラの搬送力は、シート状記録媒体に対する給紙圧を調整することでアシスト可能となる。
【０１０５】
請求項１４記載の発明によれば、給送されてきたシート状記録媒体に画像形成を行う、例えば印刷装置や複写装置等を含む画像形成装置において、請求項１ないし１３の何れか一つに記載の給紙装置を有するので、請求項１ないし１３の何れか一つに記載の発明の効果を奏する。
【図面の簡単な説明】
【図１】本発明が適用された実施形態１の給紙装置を示す、図７のＳ１−Ｓ１線断面を含む一部断面正面図である。
【図２】実施形態１の給紙装置における給送分離部周りの一部断面正面図である。
【図３】実施形態１の給紙装置における給紙駆動手段周りの要部の平面図である。
【図４】実施形態１の給紙装置における給送分離部周りの要部の拡大正面図である。
【図５】実施形態１の給紙装置における給送分離部および退避手段周りを拡大して示す一部断面正面図である。
【図６】実施形態１の給紙装置における給送分離部の各第１摩擦部材、第２摩擦部材および各給紙ローラの各幅寸法を説明するための給紙方向の上流側から見た側面図である。
【図７】実施形態１の給紙装置における給送分離部の変位規制手段周りの一部を破断して示す斜視図である。
【図８】実施形態１の給紙装置における給送分離部の第２摩擦部材の取り得る配置位置を説明した概略的な正面図である。
【図９】変形例２の給紙装置における給送分離部および変位手段周りを拡大して示す一部断面正面図である。
【図１０】本発明を適用する感熱孔版印刷装置の概略的な正面図である。
【符号の説明】
１ 第１摩擦部材
２，２Ａ 第２摩擦部材
２ａ 変位規制手段を構成する凹部としての孔
５，５Ａ 第２保持部材
５ａ 退避手段を構成する溝としての長孔
８ ガイド形状
９ 退避手段を構成する調整ネジ
１０ 案内部材としての用紙ガイド板
１０ａ 逃げとしての逃げ窓
１０ｃ 変位規制手段を構成する凸部としての爪
１１ ピックアップローラ
１２ 給紙部材としての給紙ローラ
１２ｂ 給紙ローラの軸
１４ 第１保持部材
１５ 接点
１６−１，１６−２，１６−３ 交差位置
１８ 搬送面
１９ 退避手段
３０ 給紙駆動手段
４５ 案内手段としてのスライドホルダ
４７ 付勢手段としてのバネ
４９ 変位手段
５０，５０Ａ 給送分離部
５１ 給紙台
５５ａ，５５ｂ 搬送部材としてのレジストローラ対
６０，６０Ａ 給紙装置
Ａ 給紙ローラの幅寸法
Ｂ 第１摩擦部材の幅寸法
Ｃ 各第１摩擦部材の保持間隔寸法
Ｄ 第２摩擦部材の幅寸法
Ｐ シート状記録媒体としての用紙
Ｘ４ 給紙方向
Ｙ 用紙幅方向[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a paper feeding device and an image forming apparatus having the same, and more particularly to a separation device and an image forming apparatus in a paper feeding device having an auxiliary separation mechanism for a sheet-like recording medium such as paper.
[0002]
[Prior art]
In a stencil printing apparatus as an example of a printing apparatus among image forming apparatuses, a stencil master (hereinafter simply referred to as “master”) is sent at a predetermined timing from a sheet feeding device to a plate cylinder around which a master is wound. The sheet as the sheet-shaped recording medium is pressed by pressing means such as a press roller or an impression cylinder, and the ink supplied from the inside of the plate cylinder oozes out from the perforated portion of the master by the pressing action at this time and is transferred onto the sheet. By doing so, a printed image is formed on a sheet.
In a copying apparatus, a printer, or the like, an image is formed by transferring a toner image formed on an image carrier onto a sheet sent from a sheet feeding device at a predetermined timing by a transfer unit.
[0003]
In a paper feeding device that is connected to or built in an image forming device such as a printing device, a copying device, or a printer, a plurality of sheets are placed on a paper feed tray (paper feed tray) or paper feed cassette that can be raised and lowered. The pickup roller is brought into contact with the uppermost sheet and sent out, and the paper fed out in a state where a plurality of sheets are overlapped by the pickup roller is cooperated with the paper feed roller and the separation pad (separation member) in the separation unit. They are separated and sent out one by one by working action. In this type of paper separation, the friction force between the separation pad and the paper is made larger than the friction force between the overlapping papers, so that the lower layer paper is left and only the uppermost paper is sent out. It is called a method.
In the stencil printing apparatus among the special printing apparatuses, a wide variety of sheets are used. In general, paper is classified into standard paper, thin paper, and thick paper, but can be further classified into standard paper, renewal paper, thin paper, thick paper, and special. Specific examples of applications of the sub-classification are as follows. That is, the standard paper includes high quality paper (high quality 55 kg paper, stencil high quality paper, etc.), medium quality paper, recycled paper, and the like. Thin paper includes thin paper and high-quality 45 kg paper, thick paper includes high-quality paper of 135 kg or more, drawing paper, postcards, etc. Special paper (hereinafter sometimes simply referred to as “special”) is an envelope (square, Long).
[0004]
In such a separation unit of the paper feeding device, for example, as disclosed in Japanese Patent Application Laid-Open No. 59-124633, friction members are provided on both sides of the separation pad, and the friction members are brought into contact with the back side of the paper. Therefore, a separation apparatus that performs sheet separation by deforming a sheet into a substantially U shape has been already known (hereinafter referred to as “the former technique”).
[0005]
Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-296933, in a paper guide member provided in front of a separation pad (spreading member), a friction member is provided at a predetermined distance from the left and right ends of the paper feed roller. There is also proposed a paper feeding device that performs a paper separation assist operation by deforming paper into a substantially U shape in the same manner as the separation device in the former technique (hereinafter referred to as “the latter technique”). .
[0006]
[Problems to be solved by the invention]
However, in the former technique, if the paper to be fed does not have a certain amount of stiffness, the left and right side edges of the paper are only lifted, and the separation force is not sufficiently exerted on the second and subsequent sheets. In particular, when a wave (waving) occurs at the leading edge of the paper at high temperatures and high humidity, the leading edge of the paper does not fully contact the friction members on both sides of the separation pad, and the separation force does not act. Then, multiple feeding occurs in which a plurality of sheets are simultaneously fed in a stacked state. Contrary to this, there is a problem that a stiff paper such as thick paper is likely to be unfed because the paper feeding load increases.
[0007]
With the latter technique, there is a problem that non-feeding or jamming occurs at the separation part when the thick paper is stiff, the curl of the paper is curled downward, or when the paper is wavy. is there.
[0008]
Accordingly, the present invention has been made in view of the above circumstances, and is not limited to the sheet (sheet-like recording medium) regardless of the thickness of the sheet, the strength of the waist, and the presence or absence of the wave or curl generated at the leading end of the sheet. It is an object of the present invention to provide a sheet feeding device and an image forming apparatus having a mechanism for reliably separating the above-mentioned components.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the above object, the present invention employs the following characteristic means / configurations in the invention of each claim.
According to the first aspect of the present invention, the sheet feeding medium that can be moved up and down on which a plurality of sheet-like recording media are stacked, and the sheet-like recording medium on the sheet feeding board are fed one by one from the top, and fed in order. A sheet feeding device including a feeding separation unit that feeds in a direction, and is provided at a predetermined interval in a width direction orthogonal to the sheet feeding direction and contacts an uppermost sheet-like recording medium on the sheet feeding table. Two sheet feeding members that feed in the sheet feeding direction, two first friction members that are disposed below and face each sheet feeding member and pressed toward each sheet feeding member, The sheet-like recording is performed at a position that holds the first friction member and is not in contact with each sheet feeding member on the upstream side in the sheet feeding direction from the contact point between each sheet feeding member and each first friction member. A shape for guiding the front end of the medium to each of the first friction members is provided. The first friction member disposed between the first holding member and the first friction member in the width direction, the base end side of the first friction member extending from the upstream side to the downstream side in the vicinity of the contact. It occupies an intersecting position that intersects at any position in the sheet feeding direction above, and its free end occupies a downstream position located on the downstream side of the contact point, and between the intersecting position and the downstream position A second friction member formed so as to protrude from the outer peripheral surface of the paper feed member toward the axis of the paper feed member between the width directions of the paper feed members, and a second friction member And a second holding member for holding the base end side.
Here, the dimension in the width direction of the first friction member is the dimension in the width direction in each of the sheet feeding members because the frictional resistance (separation force) of the first friction member is effectively applied to the sheet-like recording medium. It is preferable that it is formed larger.
[0010]
According to a second aspect of the present invention, in the paper feeding device according to the first aspect, the width direction dimension of the second friction member is formed smaller than the holding interval in the width direction of the first friction member. Features.
[0011]
According to a third aspect of the present invention, in the paper feeding device according to the first or second aspect, the second friction member has a thin plate shape elongated in the paper feeding direction.
[0012]
According to a fourth aspect of the present invention, in the paper feeding device according to the first, second, or third aspect, the second friction member has elasticity.
Here, “elasticity of the second friction member” means that the protruding portion of the second friction member (the portion between the intersecting position and the downstream position) is in contact with the conveyed sheet-like recording medium. Means a degree of elasticity that can be elastically bent and deformed substantially downward. As a result, the frictional resistance (separation force) of the second friction member acts on the sheet-like recording medium appropriately, and the sheet-like shape. This means that the recording medium can be reliably separated (wound).
[0013]
According to a fifth aspect of the present invention, in the paper feeding device according to any one of the first to fourth aspects, the second holding member has elasticity.
[0014]
According to a sixth aspect of the present invention, in the paper feeding device according to the first, second, or third aspect, the second friction member is substantially made of a rigid body, and the second holding member has elasticity.
[0015]
7. The sheet having been conveyed to the protruding portion (the portion between the intersecting position and the downstream position) of the second friction member according to claim 5 or 6, etc. Means that the second holding member can be elastically displaced moderately in conjunction with the pressing of the second friction member when a pressing force is applied when contacting the recording medium. As a result, the frictional resistance (separation force) of the second friction member acts appropriately on the sheet-like recording medium, which means that the sheet-like recording medium can be reliably separated (wrinkled). .
[0016]
According to a seventh aspect of the present invention, in the sheet feeding device according to any one of the first to sixth aspects, in the case of a sheet-like recording medium that is difficult to roll, the crossing position of the second friction member coincides with the contact point. If the sheet is liable to feed when contacted with a sheet-like recording medium or the second friction member that is easy to roll, the crossing position of the second friction member is the contact point. It is in any position from the position that coincides with the contact point to the downstream side from the contact point.
[0017]
According to an eighth aspect of the present invention, in the sheet feeding device according to any one of the first to seventh aspects, a sheet-like shape that is disposed on the downstream side of the respective sheet feeding members and is fed out by the respective sheet feeding members. A conveying member for further conveying the recording medium to the downstream side, and a guide member provided with a relief extending to the downstream side for guiding the sheet-like recording medium sent out by the respective sheet feeding members in the sheet feeding direction. And the free end side of the second friction member is submerged below the relief on the downstream side of the guide member, and the free end side of the second friction member can be displaced in a substantially vertical direction. And a displacement restricting means for restricting the displacement of the second friction member on the free end side in the substantially vertical direction on the downstream side of the guide member.
[0018]
According to a ninth aspect of the present invention, in the paper feeding device according to the eighth aspect, the displacement regulating means is a recess formed on one of the free end side of the second friction member and the downstream side of the guide member. And a convex portion formed on the other end of the free end side of the second friction member and the downstream side of the guide member and fitted into the concave portion.
[0019]
According to a tenth aspect of the present invention, in the sheet feeding device according to any one of the first to ninth aspects, the protruding portion of the second friction member between the intersecting position and the downstream position is the each sheet feeding member. And a retracting means for retracting the second holding member so as to be lower than the conveying surface of the sheet-like recording medium formed by the first friction member.
The sheet feeding device according to claim 10, wherein the retracting unit includes a groove formed in a vertical direction of the second holding member, and the groove, from the viewpoint that the retracting unit is configured with the simplest and low cost. It is preferable to have an adjustment screw that fits into and adjusts and holds the second holding member in the vertical direction.
[0020]
According to an eleventh aspect of the present invention, in the paper feeding device according to the first, second, or third aspect, both the second friction member and the second holding member are substantially rigid bodies, and the intersection position and the downstream position are Displacement means for automatically displacing the second holding member is provided so that the protruding portion of the second friction member in the middle is displaced downward.
[0021]
According to a twelfth aspect of the present invention, in the paper feeding device according to the fourth aspect, the second holding member is substantially formed of a rigid body, and a protruding portion of the second friction member between the intersecting position and the downstream position is provided. Displacement means for automatically displacing the second holding member so as to be displaced downward is provided.
Here, in the sheet feeding device according to claim 11 or 12, the displacement means is a guide means for guiding the second holding member in a substantially vertical direction from the viewpoint that the displacement means is configured simply and inexpensively. And an urging means for urging the second holding member substantially upward.
Further, in the sheet feeding device according to any one of claims 1 to 12, each sheet feeding member is a sheet feeding roller from the viewpoint that each sheet feeding member is configured simply and inexpensively. Is preferred.
[0022]
A thirteenth aspect of the invention is the paper feeding device according to any one of the first to twelfth aspects, wherein each of the paper feeding members is a paper feeding roller, and the feeding separation unit is the paper feeding roller. A pickup roller that is supported so as to be swingable around and capable of adjusting the paper feed pressure and picks up the uppermost sheet-like recording medium on the paper feed table, and a sheet-like recording medium conveyed by the pickup roller And a paper feed roller that feeds in a paper feed direction.
[0023]
According to a fourteenth aspect of the present invention, in an image forming apparatus for forming an image on a fed sheet-like recording medium, the sheet feeding device according to any one of the first to thirteenth aspects is provided. .
[0024]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention including examples will be described with reference to the drawings. In the conventional example to which the embodiment of the present invention is applied and each embodiment, components such as members and components having the same function and shape are denoted by the same reference numerals, and description thereof is omitted. In order to simplify the drawings and the description, even if the components are to be represented in the drawings, the components that do not need to be specifically described in the drawings may be omitted as appropriate.
First, with reference to FIG. 10, the operation of the digital heat-sensitive thermal stencil printing apparatus 200 to which the present invention is applied and its operation will be briefly described. The thermal stencil printing apparatus 200 is an example of a printing apparatus among image forming apparatuses that perform printing as image formation on a fed sheet-like recording medium.
[0025]
In FIG. 10, reference numeral 150 denotes an apparatus main body frame that forms the framework of the thermal stencil printing apparatus 200. The part indicated by reference numeral 80 on the upper part of the apparatus main body frame 150 constitutes a document reading apparatus, the part indicated by reference numeral 90 below the plate making and feeding apparatus, and the part indicated by reference numeral 100 on the left side thereof is a porous printing drum. 101 is a printing drum device, a portion denoted by reference numeral 70 on the left is a plate discharging device, a portion denoted by reference numeral 110 below the plate making and feeding device 90 is a sheet feeding device, and a portion denoted by reference numeral 120 below the printing drum 101 Indicates a printing pressure device, and a portion denoted by reference numeral 130 on the lower left side of the apparatus main body frame 150 indicates a paper discharge device.
[0026]
The paper feeding device 110 feeds the paper P as a plurality of sheet-like recording media, which can be moved up and down, and the paper P on the paper feeding base 51 one by one from the top one by one. A sheet feeding / separating unit 115 that feeds in the paper direction X4, and a pair of upper and lower registration rollers that feed the sheet P fed from the feeding / separating unit 115 between the printing drum 101 and the printing pressure device 120 at a predetermined timing. 55a and 55b. The feeding / separating unit 115 mainly includes a pickup roller 11, a paper feeding roller 112, and a separation pad 113, as will be described later.
[0027]
First, a document 60 having an image to be printed is placed on a document placing table (not shown) disposed at the top of the document reading device 80, and a plate making start key (not shown) arranged on an operation panel (not shown). Press (not shown). Along with the pressing of the plate making start key, a plate removing process is first executed. That is, in this state, the used master 61b used in the previous printing remains attached to the outer peripheral surface of the printing drum 101, which is also called a plate cylinder in the printing drum apparatus 100.
[0028]
First, when the printing drum 101 rotates counterclockwise and the rear end portion of the used master 61b on the outer peripheral surface of the printing drum 101 approaches the pair of plate release rollers 71a and 71b, the pair of rollers 71a and 71b is rotating. One discharge plate peeling roller 71a scoops up the rear end of the used master 61b, and between the discharge plate roller pair 73a, 73b and the discharge plate peeling roller pair 71a, 71b disposed on the left side of the discharge plate peeling roller pair 71a, 71b. Is discharged into the discharge plate box 74 while being conveyed in the direction of the arrow X1 by the discharge plate conveying belt pair 72a and 72b that is stretched over, the used master 61b is peeled off from the outer peripheral surface of the printing drum 101, and the discharge process is completed. At this time, the printing drum 101 continues to rotate counterclockwise. The used master 61 b that has been peeled and discharged is then compressed inside the plate discharging box 74 by the compression plate 75.
[0029]
In parallel with the plate removal process, the document reader 80 reads the document. That is, the document 60 placed on a document placing table (not shown) is transported in the directions of the arrows X2 to X3 by the rotation of the separation roller 81, the front document transport roller pair 82a and 82b, and the rear document transport roller pair 83a and 83b. It is used for exposure reading. At this time, when there are a large number of documents 60, only the lowermost document is conveyed by the action of the separating blade 84. When reading the image of the original 60, the reflected light from the surface of the original 60 illuminated by the fluorescent lamp 86 while being conveyed on the contact glass 85 is reflected by the mirror 87 and passes through the lens 88 and is made of a CCD (Charge Coupled Device). This is performed by being incident on the image sensor 89. That is, the document 60 is read by a known “reduction-type document reading method”, and the document 60 from which the image has been read is discharged onto the document tray 80A. The electrical signal photoelectrically converted by the image sensor 89 is input to an analog / digital (A / D) conversion board (not shown) in the apparatus main body frame 150 and converted into a digital image signal.
[0030]
On the other hand, in parallel with this image reading operation, plate making and plate feeding processes are performed based on the digital signalized image information. That is, the master 61 set at a predetermined portion of the plate-making and feeding apparatus 90 is pulled out from the roll state wound in a roll shape, and a platen roller 92 and a feed roller that are pressed against the thermal head 91 via the master 61. The pair 93a, 93b is transported to the downstream side of the transport path. A plurality of minute heating elements, also called minute heating elements arranged in a line on the thermal head 91, are sent from an A / D conversion board (not shown) to the master 61 thus conveyed. The thermoplastic resin film of the master 61 that selectively generates heat according to the image signal and is in contact with the generated heat generating portion is melt-pierced. In this way, image information is written as a drilling pattern by position-selective melt drilling of the master 61 according to the image information. As the master 61, one having a total thickness of 10 to 40 [mu] m in which a polyester-based thermoplastic resin film having a thickness of 1 to 5 [mu] m is bonded to a Japanese paper or synthetic fiber as a porous support is usually used. .
[0031]
The leading end of the master-making master 61a in which the image information is written is sent out toward the outer peripheral side of the printing drum 101 by the pair of feeding rollers 94a and 94b, and the traveling direction is changed downward by a guide member (not shown). The printing drum 101 in the plate feeding position state hangs down toward the expanded master clamper 102 (indicated by a virtual line). At this time, the used master 61b has already been removed from the printing drum 101 by the plate discharging process.
[0032]
When the leading end of the master-making master 61a is clamped by the master clamper 102 at a fixed timing, the printing drum 101 gradually rotates the master-making master 61a on the outer peripheral surface while rotating in the A1 direction (clockwise direction) in the figure. I will wrap it around. The rear end portion of the master-making master 61a is cut into a fixed length by a cutter 95.
[0033]
When one plate-made master 61a is wound around the outer peripheral surface of the printing drum 101, the plate-making and plate-feeding processes are finished, and the printing process is started. First, when the sheet feeding motor 39 of the sheet feeding device 110 is driven to rotate at a predetermined timing, the pickup roller 11 rotates in the clockwise direction to pick up (pick up and pick up) the uppermost sheet P on the sheet feeding table 51. And the uppermost sheet P conveyed by the pickup roller 11 is separated by the cooperative action of the paper feed roller 112 and the separation pad 113 and is directed to the registration roller pair 55a and 55b by the arrow X4. The sheet is fed in the sheet feeding direction X4. Further, when the registration motor 40 is driven to rotate at a predetermined timing, the leading edge of the paper P is printed at a predetermined timing synchronized with the rotation of the printing drum 101 in the printing drum apparatus 100 by the rotation of the registration roller pair 55a and 55b. Sent to device 120. When the fed paper P comes between the printing drum 101 and the press roller 103 as the pressing means, the press roller 103 that has been separated below the outer peripheral surface of the printing drum 101 is moved upward, so that printing is performed. The prepress master 61a wound around the outer peripheral surface of the drum 101 is pressed. In this way, ink oozes out from the perforated part of the printing drum 101 and the perforated pattern part (both not shown) of the pre-printed master 61a, and the oozed ink is transferred to the surface of the paper P to form a printed image. .
[0034]
At this time, on the inner peripheral side of the printing drum 101, ink is supplied from the ink supply pipe 104 to the ink reservoir 107 formed between the ink roller 105 and the doctor roller 106, and is in the same direction as the rotation direction of the printing drum 101. Ink is supplied to the inner peripheral side of the printing drum 101 by the ink roller 105 that is in contact with the inner peripheral surface while rotating in synchronization with the rotation speed of the printing drum 101.
[0035]
The paper P on which the printing image is formed in the printing pressure device 120 is peeled off from the printing drum 101 by the paper discharge peeling claw 114 and is adsorbed by the suction fan 118, while the suction paper discharge inlet roller 115 and the suction paper discharge outlet roller 116. As a result of the counterclockwise rotation of the conveyor belt 117 that is stretched around the sheet, the sheet is conveyed toward the sheet discharge device 130 as indicated by an arrow X5 and sequentially discharged and stacked on the sheet discharge table 52. In this way, the trial printing, also called so-called plate printing, is completed.
[0036]
Next, when the number of prints is set with a numeric keypad (not shown) provided on the operation panel and a print start key (not shown) is pressed, the steps of paper feeding, printing, and paper ejection are performed in the same process as the trial printing. The process is repeated for the set number of printed sheets, and all the processes of stencil printing are completed.
[0037]
Although the explanation will be mixed, the drive of the paper feed means (pickup roller 11 and paper feed roller 112) of the paper feed separation unit 115 is replaced with a conventional system using cams, sector gears or the like as a drive system of the paper feed means. As shown in FIG. 3, a paper feed means independent drive system is employed in which the paper drum is rotated by a paper feed motor 39 independent of the rotational drive force of a main motor (not shown) that drives the print drum 101 to rotate. .
The registration roller pair 55a, 55b is driven by a registration roller independent drive system that is rotated by a registration motor 40 that is independent of the rotational driving force of the main motor, instead of the conventional cam or sector gear system. ing.
Each of the paper feed means independent drive system and the registration roller independent drive system described above includes a holding means (for example, a paper clamper) that holds the leading end portion of the conveyed paper P as the pressing means, and is substantially the same as the outer diameter of the printing drum 101. It should be noted that when an impression cylinder of the same diameter is employed, a remarkable effect is achieved. Therefore, the sheet feeding means (pickup roller 11 and sheet feeding roller 112) of the sheet feeding separation unit 115 and the pair of registration rollers 55a and 55b are driven using cams, sector gears, etc., which are conventional sheet feeding means driving methods. Of course, it does not matter even if it is a system.
(Embodiment 1)
The first embodiment will be described with reference to FIGS.
The first embodiment is different from the heat-sensitive stencil printing apparatus 200 shown in FIG. 10 only in that it has a paper feeding device 60 shown in FIG. The paper feeding device 60 of the first embodiment is mainly different from the paper feeding device 110 shown in FIG. 10 in that it has a feeding separation unit 50 instead of the feeding separation unit 115. The sheet feeding / separating unit 50 is configured as a sheet feeding unit that feeds the sheets P on the sheet feeding table 51 one by one from the top (in other words, separates the sheets one by one) and sequentially feeds them in the sheet feeding direction X4. It has a function.
[0038]
As shown in FIGS. 1, 2, and 6, the feed separation unit 50 is supported and swingable around shafts 12 b of two feed rollers 12 and 12, which will be described later, and feed pressure can be adjusted. Pickup roller 11 that contacts and picks up the uppermost sheet P on the table 51 (see FIG. 3) and has been conveyed by the pickup roller 11 provided at a predetermined interval in the sheet width direction Y orthogonal to the sheet feeding direction X4. The paper feed rollers 12 and 12 serving as two paper feed members for feeding the paper P in the paper feed direction X4 and the paper feed rollers 12 and 12 are disposed below and opposed to the paper feed rollers 12 and 12, respectively. The two first friction members 1, 1 pressed to be in contact with each other, the first friction members 1, 1 are held from the lower side, and the paper feed rollers 12, 12 and the first friction members 1, 1 are held. On the upstream side in the paper feeding direction X4 from the contact 15 with A first holding member 14 having a guide shape 8 for guiding the leading edge of the paper P to each first friction member 1, 1 at a position that is not in contact with the outer peripheral surface of each paper feed roller 12, 12; The base roller 2b is disposed between the paper feed rollers 12 and 12 in the paper width direction Y, and the base end side 2b is on the upper surface of each first friction member 1 and 1 upstream of the contact point 15 in the paper feed direction X4. It occupies an intersecting position 16-1, and its free end 2c occupies a downstream position located downstream of the contact point 15 in the paper feeding direction X4, and the intersecting position 16-1 and the downstream position (free end 2c) 2 is formed so as to protrude from the outer peripheral surface of each paper feed roller 12, 12 toward the shaft 12 b shown in FIG. 2 between the paper width directions Y of each paper feed roller 12, 12. A friction member 2, and a second holding member 5 for holding the base end side 2b of the second friction member 2 from below. It is configured in La main.
[0039]
Hereinafter, the configuration around the feeding separation unit 50 in the sheet feeding device 60 will be described in detail.
The paper feed table 51 employs a lifting mechanism having the same configuration as the automatic intermittent lifting mechanism shown in FIGS. 3 and 8 of Japanese Utility Model Publication No. 5-18342, for example. It can be moved up and down with P loaded. The paper feed platform 51 is lifted and lowered by the lift mechanism so that the top of the stacked paper P always occupies a paper feed position in contact with the pickup roller 11 with a predetermined paper feed pressure (pressing force capable of transporting the paper P). Drive controlled.
The raising / lowering mechanism of the paper feed tray 51 is not limited to the one described above, and for example, a mechanism using a wire or the like as shown in FIG. 1 of Japanese Patent Application Laid-Open No. 59-124633 is also used.
[0040]
As shown in FIG. 3, a pair of side fences 52 a and 52 b for positioning and aligning both side edges of the paper P according to the paper size are disposed on the paper feed stand 51 so as to be movable in the paper width direction Y. .
[0041]
The pickup roller 11 is integrally fixed around a shaft 11b formed integrally with the core metal 11a, and is a known one that is rotatable together with the shaft 11b, or between the shaft 11b and the core metal 11a. A one-way clutch (not shown) is provided to support the shaft 11b so as to rotate freely when not driven. A soft high-friction material such as rubber is used for the outer peripheral portion including the outer peripheral surface of the pickup roller 11 so that the pick-up roller 11 can be easily picked when it contacts the paper P. Further, as shown in detail in FIG. 1, the outer peripheral surface portion of the pickup roller 11 is formed with substantially saw-tooth-like protrusions on the entire circumference in front view in order to increase the frictional resistance.
Each of the paper feed rollers 12 and 12 is integrally fixed around a shaft 12b formed integrally with the core metal 12a, and is rotatable together with the shaft 12b or the same support as the pickup roller 11 Sometimes take a way. As shown in detail in FIGS. 3 and 6, each paper feed roller 12, 12 can face the second friction member 2 having a width direction dimension D between each paper feed roller 12, 12. Thus, they are provided at a predetermined interval in the paper width direction Y. The outer peripheral portion including the outer peripheral surface of each of the paper feeding rollers 12 and 12 is made of a soft material such as rubber so that it can be easily fed out in the paper feeding direction X4 when it comes into contact with the paper P like the pickup roller 11. High friction material is used. Further, as shown in detail in FIG. 1, the outer peripheral surface portion of each of the paper feed rollers 12 and 12 is formed with a substantially saw-toothed projection on the entire circumference in front view in order to increase the frictional resistance. .
As the high friction material used for the outer peripheral portion of the pickup roller 11 and each of the paper feed rollers 12, 12, for example, ethylene / propylene rubber (EPDM) having a hardness of Hs 25 to 35 on the JIS-A scale is preferably used. .
[0042]
With reference to FIGS. 1 to 3, the configuration around the paper feed driving means 30 of the pickup roller 11 and the paper feed rollers 12 and 12 will be described.
As shown in FIG. 2, a one-way clutch 31 is interposed between each of the paper feed rollers 12, 12 and the shaft 12b and between the pickup roller 11 and the shaft 11b. A toothed pulley 33 is attached to the shaft 12 b of each paper feed roller 12, 12, and a toothed pulley 32 is attached to the shaft 11 b of the pickup roller 11. A timing belt 34 is stretched between the pulley 33 and the pulley 32, and the pickup roller 11 and the paper feed rollers 12 and 12 are in a driving force transmission relationship via the timing belt 34 and the one-way clutch 31. The clutch locking direction of each one-way clutch 31 (the direction in which the rotational driving force is connected) is indicated by an arrow in the figure in which the pickup roller 11 and the paper feeding rollers 12 and 12 are rotated to separate and feed the paper P. Is set in the clockwise direction. As a result, the pickup roller 11 and the paper feed rollers 12 and 12 can rotate only in the clockwise direction.
[0043]
As shown in FIGS. 2 and 3, the shaft 11b of the pickup roller 11 and the shaft 12b of each of the paper feeding rollers 12 and 12 are both fed via a rolling bearing 22 to form a U-shape having an opening on the lower side. The arm 21 is rotatably attached. The pickup roller 11 has its own weight around the shaft 12b of each paper feed roller 12, 12, the weight of the paper feed arm 21, and a spring 24 (tensile spring) attached to the upper left end of the paper feed arm 21 in FIG. By the urging force, the sheet feeding arm 21 is swingable by a predetermined angle together with the free end side so that an appropriate sheet feeding pressure is applied. As shown in FIG. 3, the shaft 12 b of each paper feed roller 12, 12 extends outside the main body side plate 59 and is rotatably supported by the main body side plate 59 via the rolling bearing 22. A toothed drive pulley 36 is fixed to the end of the shaft 12b extending to the outside of the main body side plate 59. One end of the spring 24 is attached to the upper left end of the paper feeding arm 21 in FIG. 2 and the other end is attached to the main body side plate 59 side.
[0044]
The paper feed motor 39 is composed of a stepping motor and has a function as a paper feed driving means for rotating the paper feed rollers 12 and 12 and the pickup roller 11. The paper feed motor 39 is fixed to a motor bracket 38 that is fixedly attached to the main body side plate 59 via screws. A toothed motor pulley 35 is fixed to the output shaft of the paper feed motor 39. A timing belt 37 is stretched between the driving pulley 36 and the motor pulley 35 and is in a driving force transmission relationship.
[0045]
Here, for the convenience of explanation, the detailed operation of the paper feed driving unit 30 will be described. In the case of paper feeding, by rotating the paper feeding motor 39 in the clockwise direction in FIG. 3, the rotational driving force of the paper feeding motor 39 is transferred from the motor pulley 35 to the timing belt 37, the driving pulley 36, and the shaft 12b. Then, the paper feed rollers 12 and 12 are rotated in the clockwise direction by the clutch locking action of the one-way clutch 31. At the same time, the rotational driving force of the sheet feeding motor 39 transmitted from the shaft 12b to the pulley 33 is transmitted to the pulley 32 and the shaft 11b via the timing belt 34, and then the pickup roller is driven by the clutch locking action of the one-way clutch 31. 11 rotates clockwise. As a result, both the paper feed rollers 12 and 12 and the pickup roller 11 rotate clockwise, and the uppermost paper P stacked on the paper feed table 51 is fed toward the registration roller pair 55a and 55b. It will be.
[0046]
A light shielding plate 25 is attached to the left front end in FIG. 2 of the paper feed arm 21 on the spring 24 attachment side so as to protrude in the paper feed direction X4. A non-illustrated immovable member disposed on the main body side plate 59 in the vicinity of the light shielding plate 25 is fixedly provided with a paper feeding position detection sensor 26 for detecting the paper feeding position in a manner in which the light shielding plate 25 is selectively sandwiched. Yes. The paper feed position detection sensor 26 is a transmissive photosensor.
[0047]
On the upper side of the spring 24, by adjusting the urging force (tensile force) of the spring 24, the sheet feeding pressure when the pickup roller contacts the uppermost sheet P on the sheet feeding table 51 is not shown. A paper feed pressure adjusting mechanism is provided.
The paper feed pressure adjusting mechanism has the same configuration as the paper feed pressure adjusting mechanism (150) shown in FIGS. 2 and 5 of Japanese Patent Application Laid-Open No. 7-125855 (Japanese Patent Application No. 5-273905), for example. It has.
[0048]
Each first friction member 1, 1 is formed with a width dimension B larger than the width dimension A in the sheet width direction Y shown in FIG. 6 in each of the paper feed rollers 12, 12, and has a rectangular plate shape. . Each of the first friction members 1 and 1 is made of, for example, urethane rubber (U) having high friction with respect to the paper P, and a material having a hardness of 70 to 75 on the JIS-A scale is preferably used. Each first friction member 1, 1 is formed with a width dimension B larger than the dimension A in the sheet width direction Y shown in FIG. The first friction members 1 and 1 are fixed and held on the top of the first holding member 14 by, for example, applying an adhesive.
[0049]
The friction coefficient of each first friction member 1, 1 with respect to the paper P depends on the type of the paper P, but it has a high friction coefficient corresponding to standard paper, etc., and corresponds to a thick paper from μ = 1.2. Up to μ = 0.8 is used.
The materials of the first friction members 1 and 1 are not limited to urethane rubber materials, and for example, ethylene / propylene rubber (EPDM) materials may be used.
[0050]
For example, the first holding member 14 is integrally formed of polycarbonate resin (PC), for example, with an emphasis on wear resistance due to contact with the paper P. As shown only in FIG. 1, the first holding member 14 is formed with a tunnel-like cavity portion 14 a that is hollowed out to incorporate and store the second friction member 2 and the second holding member 5.
As shown in FIGS. 2, 4 and 5, the first holding member 14 has a cross-sectional half for guiding the first friction members 1, 1 and the first holding member 14 so as to be displaceable in a substantially vertical direction. Circular guide grooves 14b (the back side of the paper is omitted) are formed on the front side and the back side of the paper. On the other hand, the stationary member on the main body side plate 59 side is provided with a guide member (not shown) having a semicircular cross section that is loosely engaged with each guide groove 14b. The guide grooves 14b of the first holding member 14 and the guide members constitute guide means for guiding the first holding member 14 and the first friction members 1 and 1 so that they can be displaced substantially in the vertical direction.
[0051]
Further, the first holding member 14 is provided with a pressure spring (compression spring) as a pressure means for urging each first friction member 1, 1 in a direction contacting the paper feed rollers 12, 12, that is, substantially upward. ) 17 (the back side of the page is omitted) is provided on the front side and the back side of the page. One end of each pressure spring 17 is in the holder portion (not shown) formed on the front side and the back side of the paper surface inside the first holding member 14, and the other end is on the stationary member on the main body side plate 59 side, Each is locked.
[0052]
A separation pressure adjustment mechanism (not shown) that adjusts the urging force of the pressure spring 17 is provided below the pressure spring 17. As this separation pressure adjusting mechanism, for example, as shown in FIG. 3 of Japanese Patent Laid-Open No. 2000-296933, the push-up rod (45) and the push-up rod (45) that push up the lower end of the spring (43) are moved up and down. Consists of an adjustment dial (47) with a cam (46)
Here, due to the urging force of each pressure spring 17, each paper feed roller 12, 12 and each first friction member 1, 1 are pressed to form a nip portion having a predetermined length in the paper feed direction X4. However, the above-described “contact 15” refers to the upstream end of the nip portion in the sheet feeding direction X4.
The guide shape 8 of the first holding member 14 is a gentle shape that has a smooth surface and does not obstruct the catching or conveyance of the paper P in order to reliably guide the leading edge of the paper P to the first friction members 1, 1. It has become.
[0053]
The second friction member 2 is made of, for example, urethane rubber (U) which is a material having high friction and elasticity with respect to the paper P, and a material having a hardness of 70 to 80 on the JIS-A scale is preferably used. The material of the second friction member 2 is not limited to a urethane rubber type material, and for example, an ethylene / propylene rubber (EPDM) type material may be used.
Although the friction coefficient of the second friction member 2 with respect to the paper P depends on the type of the paper P, it has a high friction coefficient corresponding to standard paper or the like, and μ = 0 corresponding to a thick paper from a thing of μ = 1.2. Up to 8th place is used.
The second friction member 2 is formed such that the width direction dimension D shown in FIG. 6 is smaller than the holding interval dimension C of the first friction members 1, 1 in the sheet width direction Y.
[0054]
As will be described later, when the paper P is corrected to a substantially inverted U shape by the action of the second friction member 2 and each of the first friction members 1, 1, the substantially reverse of the paper P due to the undulation generated at the leading edge of the paper. Even if the U-shape is left-right asymmetric, the second friction member 2 has a thin and thin plate shape in the paper feeding direction X4 as shown in detail in FIG. Since the slight twist is possible along the paper direction X4, the second friction member 2 can follow the paper P more.
[0055]
The arrangement position (indicated by reference numeral 2-1 in FIG. 8) of the second friction member 2 shown in FIGS. 1, 2 and 4 is the same as the intersection position 16-1 shown in FIG. It is arrange | positioned so that the position of may be occupied. The free end 2c side of the second friction member 2 can be displaced by being elastically bent in a substantially vertical direction, and the free end 2c side is disposed so as to sink under the sheet guide plate 10 as will be described later. Has been. On the free end 2c side of the second friction member 2, a hole 2a as a recess is formed through.
[0056]
As shown in FIG. 6, the width dimension A of each paper feed roller 12, the width dimension B of each first friction member 1, 1, the holding distance dimension C of each first friction member 1, 1, 2 When the magnitude relationship of the width dimension D of the friction member 2 is put together, they are in a relationship of B> A and C> D. The dimension of the first holding member 14 in the sheet width direction Y is 2B + C + α. For example, when a postcard is given as a representative example of the sheet P having a relatively small dimension in the sheet width direction Y, the post of the postcard in the sheet width direction Y It is set slightly smaller than the dimensions. In FIG. 6, reference numeral 13 denotes a retaining ring that restricts the sheet feeding rollers 12 and 12 from coming off the shaft 12 b.
[0057]
Further, the frictional resistance (F1) between each of the paper feeding rollers 12, 12 and the uppermost sheet P, the frictional resistance (F2) between the uppermost sheet P and the sheet P immediately below it, and the second friction Friction resistance (F3) between the lower paper P in contact with the member 2 and friction resistance (F4) between the lower paper P in contact with the first friction members 1 and 1 Summarizing the magnitude relationship of the frictional resistance (friction coefficient) with the relationship (F1)>(F4)>(F3)> (F2), there is a relationship between the uppermost sheet P and the sheet P immediately below it. The frictional resistance (F2) is the smallest (friction separation method).
[0058]
As shown in FIG. 1 and the like, the paper P fed by the paper feed rollers 12 and 12 is fed in the paper feed direction X4 on the transport path between the paper feed rollers 12 and 12 and the pair of registration rollers 55a and 55b. A pair of upper and lower paper guide plates 10 and 10A are provided as guide members for guiding. Each of the paper guide plates 10 and 10A is made of a sheet metal, and is attached and fixed to the main body side plate 59 side.
The upper sheet guide plate 10A is formed with its upstream side curved upward so as to form a moderately curved upper edge at the leading end of the sheet P that hits the portion immediately before the nip portion of the registration roller pair 55a, 55b. Further, the downstream side extends to a portion reaching the upper registration roller 55a.
[0059]
The lower paper guide plate 10 extends in the vertical direction to form a paper feed front wall 10e for abutting and aligning the leading ends of the paper P stacked on the paper feed tray 51 on the upstream side in the paper feed direction X4. The first holding member 14 is bent in the vicinity of the lower portion of the guide shape 8 and extends substantially linearly to a portion reaching the lower registration roller 55b.
As shown also in FIG. 7, the paper guide plate 10 extends downstream in the paper feeding direction X <b> 4 for allowing the free end 2 c of the second friction member 2 to enter under the paper guide plate 10. A relief window 10a as a relief is formed. 1, 4, and 7, the left portion of the paper guide plate 10 near the escape window 10 a extends obliquely downward to the right with respect to the flat portion of the paper guide plate 10, and the downstream flange 10 b Forming. A claw 10c is integrally formed on the downstream side flange 10b on the downstream side of the paper feed direction X4 in the paper guide plate 10 as a convex portion protruding downward and loosely fitted into the hole 2a of the second friction member 2. Yes.
[0060]
As described above, the displacement regulating means for regulating the displacement of the second friction member 2 on the free end 2c side in the substantially vertical direction on the downstream side in the paper feeding direction X4 of the lower paper guide plate 10 is the second friction member 2 side. And a claw 10c on the paper guide plate 10 side.
The displacement restricting means is not limited to the combination described above, and for example, a claw (not shown) as a convex portion integrally formed by projecting downward on the free end 2c side of the second friction member 2. A cylindrical member provided with a long hole as a concave portion protruding downward to loosely fit the claw of the second friction member 2 in the downstream side flange 10b downstream of the paper feed direction X4 in the paper guide plate 10. A combination may be used (see claim 9).
[0061]
The paper guide plate 10 extends in the vertical direction to form a paper feed front wall 10e for abutting and aligning the leading ends of the paper P stacked on the paper feed tray 51 on the upstream side in the paper feed direction X4. The holding member 14 is bent in the vicinity of the lower side of the guide shape 8 and extends substantially linearly to a portion reaching the lower registration roller 55b.
[0062]
As shown in FIG. 5 only, a relief hole 10d for adjusting / operating an adjusting screw 9 described later is formed on the paper feed front wall 10e side of the paper guide plate 10. Further, the escape window 10a of the paper guide plate 10 has the guide shape 8 of the first holding member 14 and the portions of the first friction members 1 and 1 protruding upward from the paper guide plate 10 as described above. It is formed to extend from the downstream side ridge 10b in the paper feeding direction X4 to the upstream side in the paper feeding direction X4.
[0063]
The second holding member 5 is made of, for example, a leaf spring having moderate elasticity or a thin plate made of stainless steel. One end of the second holding member 5 (upper end in FIGS. 1, 2, 4, etc.) holds and fixes the base end side 2 b of the second friction member 2 from below by, for example, applying an adhesive. The other end of the second holding member 5 (the lower end in FIGS. 1, 2 and 4 etc.) is not shown in FIGS. 1, 2 and 4 etc., but only in FIG. The retracting means 19 shown can be held so as to be movable in the vertical direction. In FIG. 1, FIG. 2, FIG. 4, etc., the other end of the second holding member 5 holds and fixes the second friction member 2 and the second holding member 5 so as to have the illustrated arrangement shape. .
[0064]
As shown in detail in FIG. 5, a long hole 5 a as a groove that is long in the vertical direction is opened on the lower end side of the second holding member 5. On the other hand, the attachment member 6 is screwed to the paper guide plate 10 with a screw (not shown) so that the lower end portion of the second holding member 5 is sandwiched between the lower end portion of the second holding member 5 facing the escape hole 10d of the paper guide plate 10. It is fastened and fixed to. The attachment member 6 is made of, for example, a sheet metal, and a female screw that can be screwed with the adjustment screw 9 is cut at a position facing the escape hole 10 d of the paper guide plate 10. The adjusting screw 9 is a stepped screw.
[0065]
As described above, the second friction member 2 and the second holding member 5, which are indicated by solid lines in FIG. 5, are transported on the paper P formed by the paper feed rollers 12, 12 and the first friction members 1, 1. As shown by the two-dot chain line in FIG. 5, the retracting means 19 retracts downward from 18 in the long hole 5 a of the second holding member 5 and fits in the long hole 5 a to move the second holding member 5 in the vertical direction. It is mainly composed of an adjusting screw 9 for adjusting and holding.
[0066]
In FIG. 5, the adjusting screw 9 is inserted from the escape hole 10d on the paper feed front wall 10e side of the paper guide plate 10 and the long hole 5a of the second holding member 5, so that paper feed errors such as double feed and non-feed do not occur. Thus, after adjusting the arrangement position of the 2nd friction member 2 according to the kind of the paper P suitably, the lower end part of the 2nd holding member 5 is made by screwing the adjustment screw 9 in the said internal thread of the attachment member 6. Can be adjusted and fixed and held. The content of adjusting the arrangement position of the second friction member 2 according to the type of the paper P will be described later with reference to FIG.
[0067]
The registration roller pairs 55a and 55b are disposed downstream of the sheet feeding rollers 12 and 12 in the sheet feeding direction X4, and are sent out from the sheet feeding rollers 12 and 12 of the sheet feeding separation unit 50. It also has a function as a conveying member that conveys the sheet P further downstream.
[0068]
Next, the operation of the sheet feeding device 60 will be described in detail with a focus on differences from the sheet feeding process (sheet feeding operation) after the plate feeding process described with reference to FIG. The paper feeding operation is performed under a command from a control device (not shown). First, a paper feeding operation in the case where a relatively thin paper P not as thick as a thick paper (drawing paper or postcard), medium quality paper, or thin paper is loaded on the paper feed tray 51 will be described.
[0069]
First, a drive motor (not shown) for raising and lowering similar to the automatic intermittent raising mechanism (hereinafter referred to as “the raising mechanism of the publication”) shown in FIGS. 3 and 8 of the above-mentioned Japanese Utility Model Publication No. 5-18342. (The drive motor 30 in the raising mechanism of the publication is rotated), so that the same raising mechanism as in the publication (the worm 31, the worm wheel 28, the pinion 29, the rack 24, the guide plate 25, When the guide pin 26 and the guide groove 27) are operated to raise the paper feed tray 51, the uppermost paper P on the paper feed tray 51 comes into contact with the pickup roller 11.
[0070]
As a result, the pickup roller 11 and the free end side of the paper feed arm 21 shown in FIG. 2 are swung and raised counterclockwise about the shaft 12b of the paper feed rollers 12 and 12, respectively. Accordingly, the light shielding plate 25 closes the optical path of the paper feed position detection sensor 26. At this time, a signal output from the paper feed position detection sensor 26 is input to the control device, and the uppermost paper P on the paper feed tray 51 comes into contact with the pickup roller 11 so that an appropriate paper feed pressure is applied and the paper is fed. When the control device determines that a possible paper feed position has been reached, the drive of the drive motor is stopped based on a command signal output from the control device, and the paper feed platform 51 is raised. Stop.
[0071]
Next, in response to a command from the control device, the paper feed motor 39 is driven to rotate at a predetermined timing, whereby the pickup roller 11 rotates in the clockwise direction to pick the uppermost paper P on the paper feed tray 51 ( Picked up and taken out) and conveyed toward the paper feed rollers 12 and 12. When the paper P on the paper feed tray 51 decreases with the picking operation of the paper P of the pickup roller 11, the paper feed tray 51 rises as described above, and the uppermost paper P on the paper feed tray 51 is always fed. The elevation is controlled so as to occupy the paper position.
[0072]
As shown in FIG. 4, the uppermost sheet P picked up by the pickup roller 11 is conveyed so as to overlap some of the sheets P below it, and each leading end Pa is a guide shape of the first holding member 14. 8 is conveyed while being contacted and guided by 8. At this time, since the guide shape 8 is inclined upward with respect to the traveling direction of the paper P and has a gentle curved surface, each paper P is transported in order from the leading edge Pa of the uppermost paper P. The leading edge Pa of the preceding uppermost sheet P first contacts the sheet feeding rollers 12 and 12 rotating in the clockwise direction simultaneously with the rotation of the pickup roller 11, and occupies the intersecting position 16-1 before and after this. In contact with the second friction member 2.
At this time, the uppermost sheet P and a plurality of sheets P below it are put together between the sheet feeding rollers 12 and 12 and the second friction member 2 and between the sheet feeding rollers 12 and 12 and the first friction member. 1 and 1, even if the sheet P enters the nip between the first friction members 1 and 1 and the paper feed rollers 12 and 12 on both sides in the width direction Y of the second friction member 2. By being pressed by the nip, in addition to the separation of the uppermost sheet P and the sheet P therebelow by the cooperative action of the sheet feeding rollers 12, 12 and the first friction members 1, 1, the sheet P is relatively thin. Since the frictional resistance (separation force) of the second friction member 2 works effectively on the paper P, reliable separation can be performed.
At this time, the second friction member 2 and the second holding member 5 both having moderate elasticity are elastic so as to bend downward as shown by a two-dot chain line in FIG. Due to the deformation, no excessive force is applied to the paper P, so that non-feeding is less likely to occur.
[0073]
Thus, the feeding force of each of the paper feed rollers 12 and 12 is given to only the uppermost paper P, and the uppermost paper P and the uppermost paper P are fed by the respective frictional resistances of the second friction member 2 and the first friction members 1 and 1. Since the frictional resistance with the lower sheet P is reduced, only one of the uppermost sheets P is separated from the lower sheet P and is fed toward the registration roller pair 55a and 55b in the sheet feeding direction X4. Sent out. Subsequent operations are performed in the same manner as described above with reference to FIG.
[0074]
Next, a description will be given of a paper feeding operation in the case where, for example, thin paper (high quality 45 kg or the like) is loaded as the paper P on the paper feed tray 51.
When thin paper is used as the paper P, the frictional resistance of the second friction member 2 to the paper P (thin paper) is reduced to prevent the paper P from being wrinkled or torn, and before pressing the plate making start key. In addition, the retracting means 19 shown in FIG. 5 is operated.
[0075]
That is, the adjustment screw 9 of the retracting means 19 shown in FIG. 5 is loosened, and two points are shown in the figure from the arrangement positions of the second friction member 2 and the second holding member 5 shown by solid lines in FIG. The second friction member 2 ′ and the second holding member 5 ′ indicated by the chain line are arranged at positions, that is, the second friction member 2 ′ between the intersection position 16-1 and the free end 2c ′. The length of the second holding member 5 ′ is such that the inverted U-shaped protruding portion is below the transport surface 18 of the paper P formed by the paper feed rollers 12, 12 and the first friction members 1, 1. The fastening position of the adjusting screw 9 with respect to the hole 5 a is adjusted, and the second holding member 5 is fixed to the mounting member 6 by tightening the screw 9 to the mounting member 6.
[0076]
Thereafter, when the plate making start key is pressed, the drive motor (not shown) is driven to rotate in the same manner as described above, and then the pickup roller 11 (not shown in FIG. Until the paper P is conveyed while being brought into contact with and guided by the guide shape 8 of the first holding member 14, the same process as described above is performed.
Each sheet P is conveyed so as to precede the leading edge Pa of the uppermost sheet P, and the inverted U-shaped protruding portion of the second friction member 2 ′ is the sheet as shown by a two-dot chain line in FIG. Since it is located below the transport surface 18 of P, the back surface of the paper P does not come into contact with the second friction member 2 ′. The leading edge Pa of the preceding uppermost sheet P contacts each sheet feeding roller 12, 12 rotating in the clockwise direction simultaneously with the rotation of the pickup roller 11, and before and after this, each first friction member 1, 1. Contact with.
[0077]
At this time, even if the uppermost sheet P and the plurality of sheets P thereunder enter the nip between the sheet feeding rollers 12 and 12 and the first friction members 1 and 1, The sheet P is pressed by the nip between each first friction member 1, 1 and each sheet feeding roller 12, 12 on both sides in the width direction Y of the second friction member 2, whereby the friction of each first friction member 1, 1 is achieved. Since only the resistance (separation force) works effectively, the uppermost paper P and the paper P below it can be reliably separated by the cooperative action of the paper feed rollers 12 and 12 and the first friction members 1 and 1. .
[0078]
Therefore, according to the paper feeding device 60 of the first embodiment, even if the paper P to be fed is a thin paper P that is relatively weak like the conventional paper feeding device, the second and subsequent paper P However, the separation force (friction resistance) by the second friction member 2 works effectively, and the separation force by the first friction members 1 and 1 acts continuously, so that double feed and non-feed occur. Therefore, it is possible to prevent paper feeding defects such as jams.
[0079]
In particular, even when a wave (waving) is generated at the leading end of the sheet P due to high temperature and high humidity, and the like, the second friction member 2 is formed long in the sheet feeding direction X4 and slightly twisted. Therefore, the separation force can be caused to follow the paper P more.
Even if the paper P is a thick thick paper, the second holding member 5 together with the second friction member 2 is elastically bent toward the transport surface 18 side of the paper P, so that an excessive force is not applied to the paper P. Non-feeding is less likely to occur.
Further, by operating the retracting means 19, it is possible to reduce the frictional resistance of the second friction member 2 with respect to a considerably thin paper, so that the paper P can be prevented from being wrinkled or torn.
Further, by providing the displacement regulating means, if a jam occurs in the paper feed path between the paper feed rollers 12 and 12 and the pair of registration rollers 55a and 55b on the downstream side, the paper feed rollers When the jammed paper P is pulled out to the 12th and 12th sides, the second friction member 2 is not pulled out together with the jammed paper P, so that the operability during the jam processing is improved and the second friction member. 2 is not damaged.
[0080]
Regarding the heat-sensitive stencil printing apparatus 200 equipped with the conventional paper feeding device 110 and the heat-sensitive stencil printing apparatus equipped with the paper feeding device 60 to which the present invention is applied, the paper P that was particularly unstable in double feeding, that is, Table 1 below shows the results of an experiment in which paper feeding is actually performed using medium-size paper and renewal paper (an experiment of passing 1000 sheets of paper P of paper size A4). .
As the thermal stencil printing device 200 equipped with the conventional paper feeding device 110, a VT1220 manufactured by Ricoh Co., Ltd. is used, and the thermal stencil printing device equipped with the paper feeding device 60 to which the present invention is applied is used for feeding the VT 1220. The only difference is that a paper feeding device 60 is installed instead of the device 110.
Each of the first friction members 1 and 1 is made of urethane rubber (U) and has a hardness of Hs70 on a JIS-A scale. The second friction member 2 is made of urethane rubber (U) and has a hardness of Hs70 on the JIS-A scale.
[0081]
[Table 1]
Figure 0004520071
[0082]
As can be seen immediately from Table 1, the paper feeding result obtained by the paper feeding device 60 to which the present invention is applied is such that there is no occurrence of double feeding on both the medium-sized paper and the renewed paper P, and a good paper passing result can be obtained. It was. On the other hand, in the conventional paper feeding device 110, a large number of double feeds occur when a medium-size paper is passed, and a multi-feed sometimes occurs when a paper is passed. There was a clear significant difference compared to the paper device 60.
[0083]
From the technical matters described above, the following can be said immediately with reference to FIG.
That is, when using paper P that is difficult to roll (separate), the positions 2-2 and 2-1 of the second friction member 2 are contact points from the intersection position 16-2 where the intersection position coincides with the contact point 15. 15 to any one of the intersecting positions 16-1 from the first friction members 1, 1 to the upstream side. In addition, when using the paper P that is likely to be separated (separated) or the paper P that is liable to cause a paper feeding failure when it is in contact with the second friction member 2, the arrangement positions 2-2 and 2-3 of the second friction member 2 are used. May be at any intersection position 16-3 from the intersection position 16-2 where the intersection position coincides with the contact point 15 to the downstream side of each first friction member 1, 1 from the contact point 15 (see claim 7). ).
[0084]
From FIG. 8 and the technical matter described above, the arrangement positions 2-1, 2-2, 2-3 of the second friction member 2 are represented by the intersection positions 16-1, 16-2, 16-3. In addition, the timing of contact with the front end of the paper P is changed in the paper feeding direction X4, and the range and size in which the frictional resistance of the second friction member 2 is effectively applied to the back surface of the front end of the paper P is also changed. Can be seen. That is, the second friction member 2 changes its placement positions 2-1, 2-2, and 2-3, thereby reducing the frictional resistance that acts on the back surface of the leading end of the paper P by each first friction member 1. In addition, the frictional resistance of the second friction member 2 can be applied to the back surface of the front end portion of the paper P by adjusting the timing and size of the frictional resistance.
(Modification 1 of Embodiment 1)
The first modification of the first embodiment is different from the first embodiment only in that the second friction member 2 is substantially made of a rigid body instead of the second friction member 2 having appropriate elasticity. (See claim 6).
[0085]
The second friction member 2 is made of, for example, a material that is hard to be deformed and has a rigidity that is not deformed by contact with any stiff paper P, for example, a stainless steel that is relatively thicker than that of the second holding member 5. It may be a sheet or sheet metal material, that is, it may be substantially rigid. And in order to give moderate frictional resistance, a grid-like uneven pattern is integrally formed on the upper surface of the second friction member 2 formed of a stainless steel plate or sheet metal material and in contact with the paper P. Alternatively, a separate body such as urethane rubber having moderate friction resistance and high hardness may be attached with an appropriate adhesive or the like.
The base end side of the second friction member 2 is fixed and held by the second holding member 5 from the lower side, for example, by welding or a planting screw. Similarly to the first embodiment, the second holding member 5 may be formed of an elastic leaf spring or a thin plate made of stainless steel, but the friction resistance of the second friction member 2 against the paper P is shown in FIG. It should be noted that it is necessary to appropriately adjust the elastic force and shape of the second holding member 5 in order to make substantially the same.
(Modification 2 of Embodiment 1)
FIG. 9 illustrates a feeding separation unit 50A of the sheet feeding device 60A according to the second modification of the first embodiment.
The second feeding member 50A according to the second modified example is substantially a second friction member made of a rigid body instead of the second friction member 2 having appropriate elasticity as compared with the feeding separation unit 50 according to the first embodiment. 2A, in place of the second holding member 5 having moderate elasticity, the second holding member 5A having a substantially rigid body, and the crossing position 16-1 and the downstream position (free end 2Ac) The main difference is that it has a displacement means 49 that automatically displaces the second holding member 5A so that the protruding portion of the second friction member 2A in between is displaced downward (see claim 11).
[0086]
As in the first modification, the second friction member 2A is, for example, a material that is not easily deformed and has a rigidity that does not deform due to contact with any stiff paper P, such as that of the second holding member 5 of the first embodiment. It may be a stainless steel plate or a sheet metal material having a relatively thick plate thickness, that is, it may be substantially rigid. And in order to give moderate frictional resistance, on the upper surface which contacts the paper P of 2nd friction member 2A, a lattice-like uneven | corrugated pattern is formed integrally, or it has high hardness with moderate frictional resistance. A separate member such as urethane rubber may be attached with an appropriate adhesive or the like.
The second holding member 5A is, for example, a stainless steel plate or a sheet metal material that is relatively thicker than that of the second holding member 5 of the first embodiment, so as not to be deformed by the downward displacement of the second friction member 2A. It may be present, that is, it may be substantially rigid. The base end side of the second friction member 2A is fixed and held by the second holding member 5A from the lower side thereof, for example, by welding or a planting screw.
[0087]
The displacement means 49 includes a slide holder 46 as a guide means for guiding the proximal end side of the second holding member 5A in a substantially vertical direction, and a spring 47 as a biasing means for biasing the second holding member 5A in a substantially upward direction. (Compression spring). A slide member 45 having a rectangular cross section is formed on the base end side of the second holding member 5A. The slide member 45 has a small resistance due to sliding and is durable, for example, polycarbonate resin (PC) or polyamide resin (PA), and is insert-molded integrally with the base end side of the second holding member 5A. . The slide holder 46 also selects and uses the same resin as the slide member 45 for the same reason.
[0088]
Next, the operation of the sheet feeding device 60A will be described in detail with a focus on differences from the first embodiment.
First, after the drive motor (not shown) is rotationally driven as in the first embodiment, the pickup roller 11 (not shown in FIG. 9) picks the top sheet P, and the top sheet P is the first holding member 14. The process is performed in the same manner as in the first embodiment until the sheet is conveyed while being in contact with and guided by the guide shape 8.
[0089]
The leading edge Pa of the preceding uppermost sheet P is in contact with each of the paper feed rollers 12 and 12 and is in contact with the second friction member 2 occupying the intersection position 16-1 before and after this.
At this time, the uppermost sheet P and a plurality of sheets P below it are put together between the sheet feeding rollers 12 and 12 and the second friction member 2 and between the sheet feeding rollers 12 and 12 and the first friction member. 1 and 1, even if the sheet P enters the nip between the first friction members 1 and 1 and the paper feed rollers 12 and 12 on both sides in the width direction Y of the second friction member 2. By being pressed by the nip, in addition to the separation of the uppermost sheet P and the sheet P therebelow by the cooperative action of the sheet feeding rollers 12, 12 and the first friction members 1, 1, the sheet P is relatively thin. Since the frictional resistance (separation force) of the second friction member 2 works effectively on the paper P, reliable separation can be performed.
At this time, for the paper P such as thick paper, such as thick paper, the second friction member 2A ′ and the second holding member 5A ′ have the slide member 45 connected to the slide holder 46 as shown by a two-dot chain line in FIG. While being guided smoothly, the spring 47 is entirely displaced against the urging force of the spring 47. As a result, an excessive force does not act on the paper P, so that there is no trouble such as non-feeding when the paper P is fed by the paper feed rollers 12 and 12. The magnitude of the overall downward displacement of the second friction member 2A ′ and the second holding member 5A ′ indicated by a two-dot chain line in FIG. 9 depends on the type of the paper P, that is, mainly the strength of the waist of the paper P. It depends on the degree. The disposing position of the displacing means 49 is fixedly disposed on the paper feed front wall 10e side of the paper guide plate 10 for simplification of illustration, but the second friction member 2A ′ and the second holding member 5A ′. It should be noted that it is better to arrange at the same position as the pressurizing spring 17 so that is smoothly displaced downward.
[0090]
As described above, the feeding force of each of the paper feeding rollers 12 and 12 is greatly applied only to the uppermost sheet P, and the highest frictional force of the second friction member 2A and each of the first friction members 1 and 1 is the highest. By reducing the frictional resistance between the paper P and the paper P below it, only one of the uppermost paper P is separated from the lower paper P and fed toward the pair of registration rollers 55a and 55b. It is sent out in the paper direction X4. Since the subsequent operations are performed in the same manner as described above, the description thereof is omitted.
Therefore, according to the second modification, the same advantages as those of the first embodiment can be obtained except for the advantages of having the retracting means 19 of the first embodiment.
(Modification 3 of Embodiment 1)
The third modification of the first embodiment is similar to the first embodiment in place of the second friction member 2A configured substantially as a rigid body as compared with the feeding separation unit 50A of the paper feeding device 60A in the second modification. The main difference is that the second friction member 2 has moderate elasticity (see claim 12).
[0091]
In the third embodiment, the sheet feeding operation is compared with the downward displacement of the second friction member 2A ′ and the second holding member 5A ′ shown by the two-dot chain line in FIG. However, only the second holding member 5A ′ is displaced downward while undergoing elastic deformation as in the first embodiment. Therefore, according to the third modification, substantially the same advantages as those of the second modification can be obtained.
[0092]
The embodiment of the present invention is not limited to the above-described one. For example, the pickup roller according to the first embodiment may be used as long as the effects described below due to the provision of the pickup roller 11 according to the first embodiment are not so much desired. 11 is removed, and instead of this, the feeding rollers 12 and 12 are fed as two sheet feeding members arranged so as to contact the uppermost sheet P on the sheet feeding table 51 and feed it in the sheet feeding direction X4. It may be provided with paper rollers 12 and 12 (refer to claim 1 and claim 13 for comparison).
The first friction members are not limited to the rectangular pad-shaped first friction members 1 and 1 shown in FIG. 7 and the like, and may be, for example, two separation rollers.
[0093]
As described above, the present invention has been described with respect to specific embodiments and modifications including examples. However, the configuration of the present invention is not limited to the above-described embodiments and modifications, and these may be appropriately selected. It will be apparent to those skilled in the art that various embodiments and examples may be configured in accordance with the necessity, purpose and application within the scope of the present invention.
For example, depending on the type of the paper P and the paper feeding / printing conditions, the second friction member 2 may be arranged at the positions shown in FIG. Embodiments in which control is performed so as to automatically move and displace downstream, and in addition to this, for example, a technique such as disclosed in Japanese Patent Laid-Open No. 2000-247467 is applied in combination, or an embodiment It is from the present invention that two second friction members 2, 2 are disposed on both sides of one first friction member 1 instead of the arrangement positions of the first friction members 1, 1 in 1 etc. It is just a technical matter that can be conceived directly and easily.
[0094]
【The invention's effect】
As described above, according to the present invention, it is possible to solve the various problems of the conventional apparatus as described above and provide a novel sheet feeding apparatus and image forming apparatus. The effects for each claim are as follows.
According to the first to third aspects of the present invention, with the above configuration, even if the uppermost sheet-like recording medium on the sheet feeding table enters the nip of the plural sheet feeding / separating unit, the sheet-like recording medium is in the second friction state. Since the first friction member and the paper feed member are pressed on both sides in the width direction of the member, the separation force (friction resistance) of the second friction member works effectively even on a relatively thin sheet-like recording medium. Therefore, reliable separation can be performed.
Depending on the type of the sheet-like recording medium, the pressing force (friction resistance) of each first friction member against each sheet feeding member is weakened, and the leading end of the sheet-like recording medium is slightly U-shaped by the second friction member. However, there are cases where there are fewer paper feed errors, but such adjustment is also possible.
For example, even when a wave (waving) is generated at the leading edge of the sheet-like recording medium, particularly at high temperatures and high humidity, the second friction member has a thin plate shape that is elongated in the sheet feeding direction, for example. Therefore, a slight twist is possible, so that the separating force can be applied following the sheet-like recording medium.
[0095]
According to a fourth aspect of the present invention, the second friction member has elasticity, so that even if the sheet-like recording medium is, for example, a thick cardboard, the second friction member is connected to each paper feed member and each first paper. In addition to the effect of the invention of claim 1, 2, or 3, an excessive force is not applied to the sheet-like recording medium. Non-feeding is less likely to occur.
[0096]
According to the fifth aspect of the present invention, the second holding member has elasticity, so that the base end side of the second friction member is held even if the sheet-like recording medium is, for example, stiff cardboard. The invention according to any one of claims 1 to 4, wherein the second holding member is elastically bent toward the conveying surface side of the sheet-like recording medium formed by each of the paper feeding members and each of the first friction members. In addition to the above effect, unreasonable force does not act on the sheet-like recording medium, and non-feeding is less likely to occur.
[0097]
According to the invention of claim 6, the second friction member is substantially made of a rigid body, and the second holding member has elasticity, so that even if the sheet-like recording medium is, for example, a thick cardboard, Since the second holding member holding the base end side of the second friction member is elastically bent toward the conveyance surface side of the sheet-like recording medium formed by each sheet feeding member and each first friction member, In addition to the effect of the invention of item 1, 2, or 3, an excessive force does not act on the sheet-like recording medium, and non-feeding is less likely to occur.
[0098]
According to the seventh aspect of the present invention, in the case of a sheet-like recording medium that is difficult to roll, the intersecting position of the second friction member is at any position from the position that coincides with the contact point to the upstream side of the contact point. If the paper feeding failure is likely to occur when contacting the recording medium or the second friction member, the intersecting position of the second friction member is located at any position from the position coincident with the contact to the downstream side of the contact. In addition to the effect of the invention described in any one of 1 to 6, the second friction member can be appropriately arranged according to the properties of the sheet-like recording medium.
[0099]
According to the eighth aspect of the present invention, the free end side of the second friction member sinks below the downstream escape of the guide member, and the displacement restricting means causes the displacement of the free end side of the second friction member. Since it is regulated in the substantially vertical direction on the downstream side of the guide member, in addition to the effect of the invention according to any one of claims 1 to 7, temporarily, each sheet feeding member and the downstream conveying member When the jam occurs between the sheet, the second friction member is not pulled out together with the jammed sheet-like recording medium when the jammed sheet-like recording medium is pulled out to each paper feeding member side. The operability during processing is improved and the second friction member is not damaged.
[0100]
According to the ninth aspect of the present invention, the displacement regulating means includes a recess formed on one of the free end side of the second friction member and the downstream side of the guide member, and the free end side of the second friction member and the guide. In addition to the effect of the invention of claim 8, the displacement restricting means can be made simple and inexpensive, by having a convex portion that is formed on either one of the downstream sides of the member and fits into the concave portion.
[0101]
According to the tenth aspect of the present invention, the protruding portion of the second friction member between the intersecting position and the downstream position is from the conveyance surface of the sheet-like recording medium formed by each paper feed member and each first friction member. In addition to the effects of the invention according to any one of claims 1 to 9, by operating the retracting means, the retracting means for retracting the second holding member so that the second holding member is retracted can be considerably reduced. Since the frictional resistance of the second friction member can be reduced with respect to the thin paper, wrinkles and tears of the sheet-like recording medium can be eliminated.
[0102]
According to the eleventh aspect of the present invention, the second friction member and the second holding member are substantially made of a rigid body, and are moved by the displacing means, for example, mainly according to the strength of the waist of the sheet-like recording medium. Since the projecting portion of the second friction member between the downstream position and the downstream position is displaced downward, in addition to the effects of the first, second, or third aspect, an unreasonable force does not act on the sheet-like recording medium, and non-feeding occurs. Less likely to occur.
[0103]
According to the twelfth aspect of the present invention, the second holding member is substantially made of a rigid body, and is displaced between the intersecting position and the downstream position by the displacing means, for example, mainly depending on the strength of the waist of the sheet-like recording medium. Since the protruding portion of the second friction member is displaced downward, in addition to the effect of the invention of claim 4, an unreasonable force does not act on the sheet-like recording medium, and non-feeding is less likely to occur.
[0104]
According to the invention described in claim 13, in addition to the effect of the invention described in any one of claims 1 to 12, the uppermost sheet-like recording medium on the sheet feeding table is picked up by the pickup roller, and While being conveyed to the first friction member, the conveyance force of each sheet feeding roller with respect to the frictional resistance of the second friction member can be assisted by adjusting the sheet feeding pressure with respect to the sheet-like recording medium.
[0105]
According to a fourteenth aspect of the present invention, in an image forming apparatus including a printing apparatus, a copying apparatus, or the like, which forms an image on a fed sheet-like recording medium, for example, according to any one of the first to thirteenth aspects. Since the paper feeding device is provided, the effect of the invention according to any one of claims 1 to 13 is achieved.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional front view including a cross section taken along line S1-S1 of FIG. 7, showing a paper feeding apparatus according to a first embodiment to which the present invention is applied.
FIG. 2 is a partial cross-sectional front view around a feeding separation unit in the paper feeding device according to the first exemplary embodiment.
FIG. 3 is a plan view of a main part around a paper feed driving unit in the paper feed apparatus according to the first embodiment.
FIG. 4 is an enlarged front view of a main part around a feeding separation unit in the paper feeding apparatus according to the first embodiment.
FIG. 5 is a partial cross-sectional front view showing an enlargement of the periphery of a feeding separation unit and a retracting unit in the paper feeding device according to the first embodiment.
FIG. 6 is a view from the upstream side in the paper feed direction for explaining the width dimensions of the first friction member, the second friction member, and the paper feed rollers of the feed separation unit in the paper feed device according to the first embodiment. It is a side view.
FIG. 7 is a perspective view showing a part of the periphery of the displacement regulating means of the feeding separation unit in the sheet feeding device of Embodiment 1 in a cutaway manner.
FIG. 8 is a schematic front view illustrating possible arrangement positions of a second friction member of a feeding separation unit in the sheet feeding device according to the first embodiment.
FIG. 9 is a partial cross-sectional front view showing an enlarged view of a periphery of a feeding separation unit and a displacement unit in a sheet feeding device according to a second modification.
FIG. 10 is a schematic front view of a heat-sensitive stencil printing apparatus to which the present invention is applied.
[Explanation of symbols]
1 First friction member
2,2A Second friction member
2a Hole as a concave part constituting the displacement regulating means
5,5A Second holding member
5a Long hole as a groove constituting the retracting means
8 Guide shape
9 Adjustment screw that constitutes the retracting means
10 Paper guide plate as guide member
10a Retreat window as escape
10c Claw as a convex portion constituting displacement regulating means
11 Pickup roller
12 Paper feed roller as paper feed member
12b Feed roller shaft
14 First holding member
15 contacts
16-1, 16-2, 16-3 Crossing position
18 Transport surface
19 Evacuation means
30 Paper feed drive means
45 Slide holder as guide means
47 Spring as a biasing means
49 Displacement means
50, 50A Feed separation unit
51 Paper feeder
55a, 55b A pair of registration rollers as conveying members
60,60A paper feeder
A Width of paper feed roller
B Width of first friction member
C Holding interval dimension of each first friction member
D Width of second friction member
P Paper as sheet-like recording medium
X4 paper feed direction
Y Paper width direction

Claims (14)

複数枚のシート状記録媒体が積載される昇降可能な給紙台と、該給紙台上のシート状記録媒体を最上のものから１枚ずつ捌いて順に給紙方向に送り出す給送分離部とを具備する給紙装置において、
前記給紙方向と直交する幅方向において所定の間隔をもって設けられ前記給紙台上の最上のシート状記録媒体に接触してこれを給紙方向に送り出す２つの給紙部材と、
前記各給紙部材に対向してその下方に配置され前記各給紙部材に向けて接触すべく押圧される２つの第１摩擦部材と、
前記各第１摩擦部材を保持し、かつ、前記各給紙部材と前記各第１摩擦部材との接点よりも前記給紙方向の上流側において前記各給紙部材と非接触である位置でシート状記録媒体の先端部を前記各第１摩擦部材に案内するための形状を備えた第１保持部材と、
前記各第１摩擦部材の前記幅方向の間に配設されていて、その基端側が前記接点近傍における前記上流側からその下流側までに至る前記各第１摩擦部材上の前記給紙方向の何れかの位置で交差する交差位置を占め、その自由端が前記接点よりも前記下流側に位置する下流位置を占め、かつ、前記交差位置と前記下流位置との間の部分が前記各給紙部材の前記幅方向の間で該給紙部材の外周面よりも該給紙部材の軸に近づく向きに突出して形成された第２摩擦部材と、
第２摩擦部材の前記基端側を保持する第２保持部材と、
を有することを特徴とする給紙装置。A sheet feeding base that can be moved up and down on which a plurality of sheet-like recording media are stacked, and a sheet feeding / separating unit that sequentially feeds the sheet-like recording media on the sheet feeding base one by one from the top and sequentially feeds them in the paper feeding direction. In a paper feeding device comprising:
Two sheet feeding members that are provided at a predetermined interval in the width direction orthogonal to the sheet feeding direction and contact the uppermost sheet-like recording medium on the sheet feeding table and feed it in the sheet feeding direction;
Two first friction members which are disposed below and face each of the sheet feeding members and pressed to contact each of the sheet feeding members;
The sheet is held at a position that holds each first friction member and is not in contact with each sheet feeding member on the upstream side in the sheet feeding direction from the contact point between each sheet feeding member and each first friction member. A first holding member having a shape for guiding the tip portion of the recording medium to each first friction member;
The first friction member is disposed between the first friction member in the width direction, and the base end side of the first friction member extends from the upstream side to the downstream side in the vicinity of the contact point in the sheet feeding direction. It occupies an intersecting position that intersects at any position, its free end occupies a downstream position located on the downstream side of the contact point, and a portion between the intersecting position and the downstream position is the respective sheet feeding A second friction member formed so as to protrude in a direction closer to the axis of the paper feed member than the outer peripheral surface of the paper feed member between the width directions of the member;
A second holding member for holding the base end side of the second friction member;
A sheet feeding device comprising: 請求項１記載の給紙装置において、
第２摩擦部材の幅方向寸法は、前記各第１摩擦部材の前記幅方向の保持間隔よりも小さく形成されていることを特徴とする給紙装置。The paper feeding device according to claim 1.
The width direction dimension of a 2nd friction member is formed smaller than the holding | maintenance space | interval of the said width direction of each said 1st friction member, The paper feeder characterized by the above-mentioned. 請求項１または２記載の給紙装置において、
第２摩擦部材は、前記給紙方向に細長い薄板状をなすことを特徴とする給紙装置。The sheet feeding device according to claim 1 or 2,
The paper feeding device, wherein the second friction member has a thin plate shape elongated in the paper feeding direction. 請求項１、２または３記載の給紙装置において、
第２摩擦部材は、弾性を有することを特徴とする給紙装置。In the paper feeding device according to claim 1, 2, or 3,
The paper feeding device, wherein the second friction member has elasticity. 請求項１ないし４の何れか一つに記載の給紙装置において、
第２保持部材は、弾性を有することを特徴とする給紙装置。In the paper feeding device according to any one of claims 1 to 4,
The sheet feeding device, wherein the second holding member has elasticity. 請求項１、２または３記載の給紙装置において、
第２摩擦部材は、実質的に剛体からなり、
第２保持部材は、弾性を有することを特徴とする給紙装置。In the paper feeding device according to claim 1, 2, or 3,
The second friction member is substantially made of a rigid body,
The sheet feeding device, wherein the second holding member has elasticity. 請求項１ないし６の何れか一つに記載の給紙装置において、
捌きにくいシート状記録媒体の場合、第２摩擦部材の前記交差位置は前記接点と一致する位置から前記接点より前記上流側までの何れかの位置にあり、
捌きやすいシート状記録媒体または第２摩擦部材に接触すると給紙不良が発生しやすい場合、第２摩擦部材の前記交差位置は前記接点と一致する位置から前記接点より前記下流側までの何れかの位置にあることを特徴とする給紙装置。In the paper feeding device according to any one of claims 1 to 6,
In the case of a sheet-like recording medium that is difficult to roll, the intersecting position of the second friction member is at any position from the position that coincides with the contact point to the upstream side from the contact point,
In the case where a paper feeding failure is likely to occur when the sheet-like recording medium or the second friction member is easily contacted, the intersection position of the second friction member is any position from the position that coincides with the contact point to the downstream side from the contact point. A paper feeder characterized by being in position. 請求項１ないし７の何れか一つに記載の給紙装置において、
前記各給紙部材における前記下流側に配設され前記各給紙部材により送り出されたシート状記録媒体をさらに前記下流側に搬送する搬送部材と、
前記各給紙部材により送り出されたシート状記録媒体を前記給紙方向に案内するための、前記下流側に延びた逃げを備えた案内部材とを有し、
第２摩擦部材の前記自由端側は、前記案内部材における前記下流側の前記逃げの下方に潜り込んでおり、
第２摩擦部材の前記自由端側は、略上下方向に変位可能であり、
第２摩擦部材の前記自由端側の変位を前記案内部材の前記下流側で略上下方向に規制する変位規制手段を有することを特徴とする給紙装置。The sheet feeding device according to any one of claims 1 to 7,
A conveying member that is disposed on the downstream side of each of the sheet feeding members and further conveys the sheet-like recording medium sent out by each of the sheet feeding members to the downstream side;
A guide member provided with a relief extending to the downstream side for guiding the sheet-like recording medium sent out by each of the paper feed members in the paper feed direction,
The free end side of the second friction member is submerged below the relief on the downstream side of the guide member,
The free end side of the second friction member is displaceable in a substantially vertical direction,
A sheet feeding device comprising displacement regulating means for regulating displacement of the second friction member on the free end side in a substantially vertical direction on the downstream side of the guide member. 請求項８記載の給紙装置において、
前記変位規制手段は、第２摩擦部材の前記自由端側および前記案内部材の前記下流側の何れか一方に形成された凹部と、第２摩擦部材の前記自由端側および前記案内部材の前記下流側の何れか他方に形成され前記凹部に嵌入する凸部とを有することを特徴とする給紙装置。The paper feeding device according to claim 8.
The displacement restricting means includes a recess formed on one of the free end side of the second friction member and the downstream side of the guide member, the free end side of the second friction member, and the downstream side of the guide member. And a convex portion that is formed on any one of the sides and fits into the concave portion. 請求項１ないし９の何れか一つに記載の給紙装置において、
前記交差位置と前記下流位置との間の第２摩擦部材の突出部分が前記各給紙部材と前記各第１摩擦部材とで形成されるシート状記録媒体の搬送面よりも下方になるように、第２保持部材を退避させる退避手段を有することを特徴とする給紙装置。The sheet feeding device according to any one of claims 1 to 9,
The protruding portion of the second friction member between the intersecting position and the downstream position is below the conveyance surface of the sheet-like recording medium formed by each of the sheet feeding members and each of the first friction members. A sheet feeding device having a retracting means for retracting the second holding member. 請求項１、２または３記載の給紙装置において、
第２摩擦部材および第２保持部材は、共に実質的に剛体からなり、
前記交差位置と前記下流位置との間の第２摩擦部材の突出部分が下方に変位するように、第２保持部材を自動的に変位させる変位手段を有することを特徴とする給紙装置。In the paper feeding device according to claim 1, 2, or 3,
The second friction member and the second holding member are both substantially rigid bodies,
A sheet feeding apparatus comprising: a displacement unit that automatically displaces the second holding member so that a protruding portion of the second friction member between the intersecting position and the downstream position is displaced downward. 請求項４記載の給紙装置において、
第２保持部材は、実質的に剛体からなり、
前記交差位置と前記下流位置との間の第２摩擦部材の突出部分が下方に変位するように、第２保持部材を自動的に変位させる変位手段を有することを特徴とする給紙装置。The sheet feeding device according to claim 4, wherein
The second holding member is substantially made of a rigid body,
A sheet feeding apparatus comprising: a displacement unit that automatically displaces the second holding member so that a protruding portion of the second friction member between the intersecting position and the downstream position is displaced downward. 請求項１ないし１２の何れか一つに記載の給紙装置において、
前記各給紙部材は、給紙ローラであり、
前記給送分離部は、前記給紙ローラ周りに揺動自在かつ給紙圧調整可能に支持され前記給紙台上の最上のシート状記録媒体に接触してピックするピックアップローラと、該ピックアップローラにより搬送されてきたシート状記録媒体を前記給紙方向に送り出す前記給紙ローラとを有することを特徴とする給紙装置。The sheet feeding device according to any one of claims 1 to 12,
Each of the sheet feeding members is a sheet feeding roller,
The feed separation unit is supported so as to be swingable around the paper feed roller and capable of adjusting the paper feed pressure, and picks up a roller that contacts and picks up the uppermost sheet-like recording medium on the paper feed table, and the pickup roller And a sheet feeding roller that feeds the sheet-like recording medium conveyed by the sheet feeding direction in the sheet feeding direction. 給送されてきたシート状記録媒体に画像形成を行う画像形成装置において、
請求項１ないし１３の何れか一つに記載の給紙装置を有することを特徴とする画像形成装置。In an image forming apparatus that forms an image on a fed sheet-shaped recording medium,
An image forming apparatus comprising the paper feeding device according to claim 1.
JP2001135095A 2001-05-02 2001-05-02 Paper feeding device and image forming apparatus Expired - Fee Related JP4520071B2 (en)

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