JP2005031432A

JP2005031432A - Electrophotographic process unit

Info

Publication number: JP2005031432A
Application number: JP2003196667A
Authority: JP
Inventors: Yoshihiko Tanaka; 好彦田中; Hiroshi Emori; 弘江森; Seizo Kitagawa; 清三北川; Tadashi Asakawa; 唯志浅川; Takeshi Kumagai; 健熊谷
Original assignee: Fuji Electric Imaging Device Co Ltd
Current assignee: Fuji Electric Imaging Device Co Ltd
Priority date: 2003-07-14
Filing date: 2003-07-14
Publication date: 2005-02-03

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic process unit provided with a toner sealing structure which hardly causes toner leakage without imparting strong pressing force to the peripheral surfaces of both end parts of a developing roller, then, enables an inexpensive motor having low torque to be used. <P>SOLUTION: In the electrophotographic process unit provided with the toner sealing structure where the developing roller feeding toner to the surface of a photoreceptor while being rotated is fixed to a frame body disposed so as to be opposed to the peripheral surfaces of both end parts of the roller and which is pressed by and is brought into slidable contact with a napped sealing member 9b provided with ground fabric 9b-3 and a napped fiber group 9b-1 to which hair fall-down working is performed, the napped sealing member 9b is fixed to the frame body so that an assumed cross angle 7c between the hair fall-down direction C of the napped fiber group 9b-1 and the rotating direction A of the developing roller 7 is set so as to make the direction of force that the toner receives by the napped fiber group and the rotation of the roller coincide with a direction including axial direction moment directed in the center part direction of the roller. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、電子写真方式の画像形成装置に搭載されるプロセスユニットにおけるトナーのシール構造に関する。
【０００２】
【従来の技術】
電子写真方式の画像形成装置は、電子写真感光体ドラムの外周面近傍に配置された帯電、露光、現像、転写、クリーニング、除電等の電子写真プロセス部材と紙に転写された画像を定着して出力する部材を少なくとも備えている。前記各電子写真プロセス部材は、たとえば、ドラムユニットと現像ユニット等の各ユニット内およびその周辺部に纏められて配設されることにより、修理や部品交換の際の取り付け、取り外し作業を容易にしている。このようなドラムユニットと現像ユニットの概略断面図を図３に示す。図３でドラムユニット５０と現像ユニット１００とは下記説明の感光体ドラム１と現像ローラ７間で分けられる。
【０００３】
前記電子写真プロセスによる画像形成は図３に示す前記ドラムユニット５０内の感光体ドラム１の表面を均一に帯電し、この帯電面を目的の画像に対応するパターンで露光部材２により露光することにより感光体ドラム１表面上に静電潜像（不図示）を形成し、この潜像を現像ユニット１００のトナー３により現像して可視像化し、転写部材４により用紙（不図示）に転写して定着する（不図示）ことにより行なわれる。前記現像に関し、トナ―３として、非磁性一成分トナーを用いる場合について詳述すると、現像ユニット１００のトナー収容部５に収納される非磁性一成分トナー３は、現像ユニット１００を構成する供給ローラ６を経て現像ローラ７へ搬送され、現像ローラ７上で帯電と薄層化された後、現像ローラ７の回転と共に前記ドラムユニット５０内の感光体ドラム１表面へ搬送されて、前述のように潜像を可視像化する。この際、感光体ドラム１の表面領域へ搬送されるべきトナー３は、前記表面領域以外には現像ユニット１００の外部に漏れないようにトナーシールが施される必要がある。この従来のトナーシール構造の概略を図６の斜視図に示す。このトナーシール構造は現像ローラ７の両端部周面８に起毛シール部材９ａを押圧する構造である。ただし、このようなトナーシールを施しても、現状ではトナー漏れは充分に防ぐことが難しい。
【０００４】
前述のように、現像ローラ７の両端部周面８からトナー漏れがあると、このトナー３は、まだ、ほとんど帯電されていない段階のトナー３のため、特に反転現像では、均一帯電された感光体１の感光層１０の両端部周面の未露光部にも付着する（帯電されたトナーは付着しない）。さらにこの付着が繰り返されて表面の保持力以上に蓄積されると、用紙搬送路上に落下して用紙端部にトナー３が付着する等の結果となり、画像欠陥となる。
【０００５】
このトナー漏れについては、特に、トナーの収容部５から供給ローラ６と現像ローラ７の表面を介してトナー３を感光体１表面へ搬出する際に現像ローラ７の両端部周面８から外部へ特に漏れ易いので、その両端部にトナーシールが施される必要がある。通常このシールは現像ローラ７の両端部周面８に所定の間隔で対向する枠体（ハウジング）の内面に起毛シール部材９ａを接着等により固着させて、回転する現像ローラ７に起毛部を押圧して摺接させることにより、ローラ７中央の機能領域にあるトナー３が両端部周面８から外部へ漏れ出ないようにシールしている。
【０００６】
このようなトナーのシールに用いられるシール部材は、スポンジ等に裏打ちされた基材に植毛された起毛繊維、または基材となる布に織り込まれたカットパイル繊維等を利用して回転部材に押圧してなるシール部材が知られている（特許文献１、２、３、４、７）。さらに基材上に植毛により起毛シール部材を形成する方法および前記基材または起毛繊維群についても、既によく知られている（特許文献２）。さらに、前記シール部材の起毛繊維には、平行な繊維群の並び列を有するものや高密度の繊維群が互いに絡み合ってフェルト状になったものが知られている（特許文献５、６）。
【０００７】
【特許文献１】
実開平６−１６９６３号公報
【特許文献２】
特開平９−２６９６５６号公報
【特許文献３】
登録実用新案第３０６５１３６号公報
【特許文献４】
特開２００２−１３２０４３号公報
【特許文献５】
特開２００１−１９４９０２号公報
【特許文献６】
特開２００１−１９４９０５号公報
【特許文献７】
特開平１１−６１１０１号公報
【０００８】
【発明が解決しようとする課題】
しかしながら、前記フェルト状のシール部材は繊維が高密度であって、互いに絡み合っているため、フェルト状のシール部材の中に入り込んだトナーはシール部材を通過して外部に漏出することは少ないが、逆にトナーがフェルト内に蓄積され易く、その場合、トナーが過剰に蓄積されたフェルトはシール効果の低下により漏れが生じることがあり、シール効果の長期持続性に問題がある。
【０００９】
また、図６に示す従来のトナーシール構造では、起毛シール部材９ａの起毛繊維側を上側にした図７の斜視図に示すように、スポンジ９ａ−２に裏打ちされた基布９ａ−３に植毛された起毛繊維群９ａ−１は現像ローラ７の回転方向Ａに平行な毛倒し方向Ａを有するので、毛倒し方向Ａに沿ってトナー３が取り込まれて移動し易く、取り込まれてもフェルトのように蓄積することは少ないが、現像ローラ７の回転と共にトナー３が線状に漏れて、漏れたトナーが対向する感光体ドラム１の表面に首輪（リング）１１状に未帯電トナーが付着することがある。この付着トナーが用紙上に落下して用紙を汚すことになり、問題となる。さらに、図６では供給ローラ６と現像ローラ７と感光体ドラム１の概略位置関係およびそれらの回転方向をそれぞれ矢印で示し、不図示のハウジングに固着される起毛シール部材９ａについては、（円弧状の起毛シール部材９ａの内面側にある）起毛繊維群の矢印方向の毛倒し方向を固着側（図面の手前側）から透視的（実際には基布およびスポンジ基材が不透明のため、固着側から毛倒し方向は見えない）に示すために点線で示した。この起毛シール部材９ａは現像ローラ７の両端部周面８に押圧される。図中にはまた、この結果漏れ出たトナー３が感光体ドラム１の対向する両端部に首輪状１１に付着することを示した。
【００１０】
このように従来のトナーシール構造では、比較的トナーが漏れ出やすいので押圧力を強くする必要がある。ところが、このトナー漏れを防ぐために強い押圧力で起毛シール部材を現像ローラに摺接させると、ローラ回転用の駆動モーターに大きい負荷がかかるので、高価な高トルクモーターが必要となり、コストの面で問題となる。
【００１１】
本発明は、以上述べた点に鑑みてなされたものであり、現像ローラの両端部周面に強い押圧力をかけなくても、トナー漏れの生じることが少なく、低トルクモーターを使うことのできるトナーシール構造を備える電子写真用プロセスユニットを提供することを目的とする。
【００１２】
【課題を解決するための手段】
請求項１記載の本発明によれば、前記目的は、トナーを感光体表面へ、回転しながら搬送する現像ローラが、このローラの両端部周面に対向するように配設された枠体に固着され、基布と、この基布に植毛され、予め毛倒し加工された起毛繊維群を備える起毛シール部材による押圧および摺接を受けてなるトナーシール構造を備える電子写真用プロセスユニットにおいて、毛倒し加工された起毛繊維群の毛倒し方向と前記現像ローラの回転方向との想定交差角度を、前記毛倒し加工された起毛繊維群と前記ローラの回転とによりトナーの受ける力の方向が前記ローラの中央部方向に向かう軸方向モーメントを含む方向となるように設定にして、前記起毛シール部材が前記枠体に固着されている電子写真用プロセスユニットとすることにより、達成される。
【００１３】
請求項２記載の本発明によれば、前記想定交差角度を１５度乃至６０度のいずれかの角度に設定した前記起毛シール部材を枠体に固着したトナーシール構造を備える請求項１記載の電子写真用プロセスユニットとすることが好ましい。
【００１４】
請求項３記載の本発明によれば、起毛繊維群がフッ素系繊維である請求項１または２記載の電子写真用プロセスユニットとすることが望ましい。
【００１５】
【発明の実施の形態】
以下、本発明の電子写真感光体に関し、図を用いて詳細に説明する。本発明はその要旨を超えない限り、以下、説明する実施例に限定されるものではない。
【００１６】
図１は本発明にかかる電子写真用プロセスユニットに用いられるトナーシール構造の要部を示す斜視図であり、図２は本発明にかかるトナーシール構造に使われる起毛シール部材の起毛繊維を上側にした要部斜視図、図４は現像ユニット中において、現像ローラの両端部にトナーシール部材が押圧されてなるトナーシール構造を軸方向から見た側方断面図、図５は現像ユニット中の現像ローラのトナーシール構造をローラの軸に垂直で上方から見た要部断面図、図８は起毛シール部材の厚さ方向の拡大断面図である。
【００１７】
なお、本発明で言う電子写真用プロセスユニットの概念は、前述の電子写真プロセスのうち、少なくとも現像プロセスを構成する部材を含むプロセスユニットを意味するので、現像ユニットはもちろんプロセスユニットに含まれるが、例えば、前記ドラムユニットと現像ユニットとが一体になったユニット等も本発明で言う電子写真用プロセスユニットの概念に含まれる。
【００１８】
そのような本発明にかかる電子写真用プロセスユニットは、前記図３に示す従来の電子写真用プロセスユニットの概略断面図と図示しない細部を除けば、ほぼ同じであるので、同じ部材は同符号を用いて本発明にかかる電子写真用プロセスユニットを説明する。供給ローラ６は、回転によりトナー収容部５のトナー３を現像ローラ７に供給する機能を持ち、現像ローラ７と同方向に接触回転するので、接触部での回転方向は互いに逆方向となる。現像ローラ７に搬送されたトナー３は、ローラ７上で層厚規制部材により帯電を受けながら、回転により感光体ドラム１の表面に搬送されて、ドラム１表面の静電潜像を現像する。図１に示す現像ローラ７と供給ローラ６が現像ユニット１００に含まれ、感光体ドラム１がドラムユニット５０に属する場合の構成は、前述した図３とトナーシール構造以外は同じであってよい。
【００１９】
図１に示すように、本発明にかかるトナーシール構造の一方の端部を示す斜視図では、矢印方向に回転する感光体１と、接触部において同方向回転する現像ローラ７の矢印で示す回転方向に対して、このローラ７の一方の端部周面８に押圧されることになる円弧状の起毛シール部材９ｂを押圧部から離した状態を示す。この起毛シール部材９ｂでは円弧の内面側に設けられている起毛繊維群９ｂ−１が、図示の矢印Ｃで示す斜め方向に向けた状態で、予め毛倒し加工されていることを示す。起毛シール部材９ｂの円弧の外面側は不図示の枠体（ハウジング）に接着されることになる。この起毛シール部材９ｂのユニット中における実際の装着状態は後述の図５で示す。また、このシール構造では動作中（ローラの回転中）の起毛シール部材９ｂにトナー３が接触すると、前記斜め方向に向けて毛倒し加工された起毛繊維群９ｂ−１により、常にトナー３はローラ７の軸７ａの方向Ｂ、すなわち、ローラの中央方向に向かう力のモーメントを受けるので、起毛シール部材９ｂから外部へトナー３の漏出することが少なくなり、前述した従来のトナーシール構造（図６）のように感光体１表面の両端部に首輪状１１にトナー３が付着して、画像欠陥となる問題が解消される。
【００２０】
図１に示す起毛シール部材９ｂでは、斜め方向Ｃを向いた起毛繊維群９ｂ−１の毛倒し加工の状態がわかりにくいので、図２に起毛シール部材９ｂを起毛繊維群９ｂ−１の毛倒し加工側から拡大して見た要部斜視図を示す。図２は、基布９ｂ−３に植毛または織り込まれた起毛繊維群９ｂ−１の毛倒し方向Ｃが現像ドラム７に押圧された時にローラ７の回転方向Ａに対して、１５度乃至６０度の角度のいずれかの角度となるように設定されている。この角度を図１では矢印Ａと矢印Ｃとの想定交差角７ｃとして示す。起毛繊維の材料として、公知の繊維材を使うことができるが、非磁性一成分正帯電トナーの場合は、起毛繊維による摩擦帯電系列を考慮すると、フッ素系高分子材料が好ましい。繊維の長さは２〜４ｍｍが好ましい。なお、以下の説明では、植毛された起毛繊維には、織り込まれたものを含むものとする。
【００２１】
図４の本発明にかかるトナーシール構造を示す側方断面図は、トナーシール構造を除いて、前記図３に示す従来の現像ユニット１００とほぼ同じ断面構造を持ち、現像ローラ７の両端部周面８のところの断面と、供給ローラ６の任意のところの断面とを、前述の図１で説明した現像ローラ７の軸７ａの方向Ｂから見た拡大断面図である。現像ローラ７の両端部周面８は、この周面８に所定の間隔で対向するハウジング（枠体）１３の内側に接着された本発明にかかる起毛シール部材９ｂによる押圧を受けて回転するので、現像ローラ７の両端部周面からトナーが漏れ出ることがほとんど無くなる。符号５はトナー収容部、符号３はトナー、符号１４はトナー収容部５と供給ローラ６とを分ける仕切り板をそれぞれ示す。
【００２２】
図５のトナーシール構造を示す上方（ローラの軸７ａ方向Ｂに直交する方向）から見た模式的要部断面図は、現像ユニット１００におけるトナー収容部５と現像ローラ７と供給ローラ６とドラムユニット中の感光体ドラム１の端部との位置関係および起毛シール部材の押圧する両端部周面８との関係を示す。トナー収容部５中のトナー３は供給ローラ６側の仕切り板１４を超えて供給ローラ６に達すると、供給ローラ６の回転により、現像ローラ７に搬送される。現像ローラ上のトナー３は両端部周面８において、起毛シール部材９ｂによる押圧を受けると、トナー３に中央部に戻す方向の力のモーメントが働くように、起毛繊維群の毛倒し加工の方向が設定されているので、トナーが現像ユニット外部に漏れ出ることが少なくなる。
【００２３】
前記起毛シール部材９ｂは、図８の要部断面図に示すように、コットン、ポリエステル、ポリプロピレン、アクリル、ポリアミドなどの繊維からなる平織り布などを基布９ｂ−３として、テトラフルオロエチレンなどのフッ素系繊維９ｂ−１の６〜１５デニールのものをパイル糸密度４〜８万本／（インチ）^２で立毛（植毛）し、さらに１００〜１５０℃に加熱したヒートローラで、基布９ｂ−３の面方向に押圧して立毛を寝かせると共に、さらにローラの回転方向に対して所定の角度となるように毛倒し加工したものである。前記ローラの回転方向に対して所定の角度となるように毛倒し加工することを除く毛倒し加工の方法自体については、前記特許文献７の３頁に詳細が記載されている方法を採用することができる。本発明との比較のために、前記特許文献７の記載のような毛倒し加工した従来の起毛シール部材９ａの斜視図を図７に示す。このシール部材９ａでは毛倒し方向Ａはローラの回転方向と平行であり、さらに、起毛シール部材９ａでは起毛繊維群９ａ−１が基布９ａ−３に植毛され、さらにスポンジなどのクッション材９ａ−２に裏打ちされている。
【００２４】
ただし、前記特許文献７には、毛倒し方向を本発明のように、ローラの回転方向に対して、所定の角度付けを設けることに対する記載や示唆は見当たらない。本発明にかかる毛倒し加工の際の方向づけについては、基布面の直交する織り糸の織り目を基準に、角度付けして毛倒しする方法と、一旦基布の前記織り目に平行に毛倒しした後に、本発明にかかる起毛シール部材として、所要の寸法に切断する際に、前記毛倒し方向が角度付けされるように、基布の前記織り目に対して基布を斜めに切断することにより、毛倒し方向の角度付けを施す方法がある。
【００２５】
一方、本発明にかかる起毛シール部材９ａは前記のようなクッション材を裏打ちされていない。スポンジのような裏打ちがされると、スポンジ中に取り込まれたトナーが時間と共に増加してトナー漏れの発生源になることが分かったためである。
【００２６】
（実験例）
次に本発明にかかるプロセスユニットのトナーシール構造における起毛シール部材の起毛繊維群の毛倒しの方向に関する効果を確認するために下記のような実験を行った。
【００２７】
布基材に織り込まれたテトラフッ化エチレンからなる３ｍｍ長の起毛繊維群（１５ｍｇ／ｃｍ^２）の毛倒しの方向をローラの回転方向との交差角度が０度、１０度、１５度、３０度、４５度、６０度、７５度、９０度とした各起毛シール部材（５ｍｍ幅）を用いたトナーシール構造を備えるプロセスユニットを元の３分の２のトルクにした低トルクモーターに変更した市販の電子写真方式のプリンターを改造し、起毛繊維によるシールの押圧力を元のシールの押圧力の２分の１に下げて組み込み、３万枚の連続耐刷試験を行い、３万枚後の印字画像を、トナー漏れによる用紙端部の汚れの有無により評価した。その結果を下記表１に示す。
【００２８】
【表１】

【００２９】
表１から、起毛繊維群の毛倒しの方向とローラの回転方向との交差角度を０度または９０度の角度としたとき、トナー漏れがひどく、画像の状態も非常に悪いが、起毛繊維群の並び列を現像ローラの回転方向に対して、前述のように本発明にかかる方向の斜め角度とすると本発明の効果により、トナー漏れが急激に少なくなり、７５度以下、１０度以上では、画像評価から見て問題がない角度と言える。さらに６０度以下、１５度以上の交差角度範囲ではトナーによる画像汚れが認められず、良好な画像となり、特に好ましい角度範囲であることが分かる。
【００３０】
【発明の効果】
本発明によれば、トナーを感光体表面へ、回転しながら搬送する現像ローラが、このローラの両端部周面に対向するように配設された枠体に固着され、基布と基布の織り目に植毛され、予め毛倒し加工された起毛繊維群を備える起毛シール部材による押圧および摺接を受けてなるトナーシール構造を備える電子写真用プロセスユニットにおいて、予め、毛倒し加工された起毛繊維群の毛倒し方向と前記現像ローラの回転方向との想定交差角度を、前記毛倒し加工された起毛繊維群と前記ローラの回転とによりトナーの受ける力の方向が前記ローラの中央部方向に向かう軸方向モーメントを含む方向となるような設定で、前記起毛シール部材が前記枠体に固着されている電子写真用プロセスユニットとしたので、現像ローラの両端部周面に強い押圧力をかけなくても、トナー漏れの生じることが少なく、安価な低トルクモーターを使うことのできるトナーシール構造を備える電子写真用プロセスユニットを提供することができる。
【図面の簡単な説明】
【図１】本発明の電子写真用プロセスユニットに用いられるトナーシール構造の要部斜視図
【図２】本発明にかかるトナーシール構造に使われる起毛シール部材の要部斜視図
【図３】従来の電子写真用プロセスユニットの概略断面図
【図４】本発明にかかる現像ユニット中の現像ローラのトナーシール構造を示す側方断面図
【図５】本発明にかかる現像ユニット中の現像ローラのトナーシール構造を示す上方から見た断面図
【図６】従来のトナーシール構造の概略斜視図
【図７】従来の起毛シール部材の要部斜視図
【図８】本発明にかかる起毛シール部材の断面図
【符号の説明】
１感光体ドラム
３トナー
５トナー収容部
６供給ローラ
７現像ローラ
７ａ現像ローラの軸
７ｃ回転方向と毛倒し方向との交差角度
８両端部周面
９ｂ起毛シール部材
９ｂ−１起毛繊維群
９ｂ−３基布
１３ハウジング（枠体）
１００現像ユニット
Ａ現像ローラの回転方向
Ｂ現像ローラの軸方向
Ｃ起毛繊維群の毛倒し方向[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner seal structure in a process unit mounted on an electrophotographic image forming apparatus.
[0002]
[Prior art]
An electrophotographic image forming apparatus fixes an image transferred on paper and an electrophotographic process member such as charging, exposure, development, transfer, cleaning, and static elimination disposed near the outer peripheral surface of the electrophotographic photosensitive drum. At least a member for outputting is provided. Each of the electrophotographic process members is, for example, arranged in each unit such as a drum unit and a developing unit and in the periphery thereof, thereby facilitating attachment and detachment when repairing or replacing parts. . A schematic sectional view of such a drum unit and a developing unit is shown in FIG. In FIG. 3, the drum unit 50 and the developing unit 100 are divided between the photosensitive drum 1 and the developing roller 7 described below.
[0003]
In the image formation by the electrophotographic process, the surface of the photosensitive drum 1 in the drum unit 50 shown in FIG. 3 is uniformly charged, and the charged surface is exposed by the exposure member 2 in a pattern corresponding to the target image. An electrostatic latent image (not shown) is formed on the surface of the body drum 1, this latent image is developed with the toner 3 of the developing unit 100 to be visualized, and transferred to a sheet (not shown) by the transfer member 4. This is done by fixing (not shown). Regarding the development, the case where a nonmagnetic one-component toner is used as the toner 3 will be described in detail. The nonmagnetic one-component toner 3 accommodated in the toner accommodating portion 5 of the developing unit 100 is a supply roller constituting the developing unit 100. 6 is transferred to the developing roller 7, charged and thinned on the developing roller 7, and then transferred to the surface of the photosensitive drum 1 in the drum unit 50 as the developing roller 7 rotates. Visualize the image. At this time, the toner 3 to be transported to the surface area of the photosensitive drum 1 needs to be sealed so that it does not leak outside the developing unit 100 except for the surface area. An outline of this conventional toner seal structure is shown in the perspective view of FIG. This toner seal structure is a structure in which the raised seal member 9 a is pressed against the peripheral surface 8 at both ends of the developing roller 7. However, even if such a toner seal is applied, it is difficult to sufficiently prevent toner leakage at present.
[0004]
As described above, if toner leaks from the peripheral surface 8 at both ends of the developing roller 7, the toner 3 is the toner 3 at a stage where it is hardly charged. It also adheres to the unexposed portions on the peripheral surfaces of both ends of the photosensitive layer 10 of the body 1 (the charged toner does not adhere). Furthermore, if this adhesion is repeated and accumulated more than the holding force of the surface, it will fall on the paper conveyance path and the toner 3 will adhere to the edge of the paper, resulting in image defects.
[0005]
With regard to this toner leakage, in particular, when the toner 3 is carried out from the toner container 5 to the surface of the photosensitive member 1 through the surfaces of the supply roller 6 and the developing roller 7, the peripheral surface 8 at both ends of the developing roller 7 is exposed to the outside. Since it is particularly easy to leak, toner seals must be applied to both ends thereof. Usually, this seal is fixed by adhering a raised seal member 9a to the inner surface of a frame (housing) facing the circumferential surface 8 at both ends of the developing roller 7 at a predetermined interval, and presses the raised portion against the rotating developing roller 7. Thus, the toner 3 in the functional area at the center of the roller 7 is sealed so as not to leak out from the peripheral surface 8 at both ends.
[0006]
The seal member used for sealing the toner is pressed against the rotating member by using raised fibers planted on a base material backed by a sponge or the like, or cut pile fibers woven into a base material cloth. A sealing member is known (

Patent Documents

1, 2, 3, 4, 7). Furthermore, a method for forming a brushed seal member by flocking on a base material and the base material or the raised fiber group are already well known (Patent Document 2). Further, the raised fibers of the seal member are known to have a parallel arrangement of fiber groups or a high density fiber group intertwined into a felt shape (Patent Documents 5 and 6).
[0007]
[Patent Document 1]
Japanese Utility Model Publication No. 6-16963 [Patent Document 2]
JP-A-9-269656 [Patent Document 3]
Registered Utility Model No. 3065136 [Patent Document 4]
JP 2002-132043 A [Patent Document 5]
JP 2001-194902 A [Patent Document 6]
JP 2001-194905 A [Patent Document 7]
JP-A-11-61101 [0008]
[Problems to be solved by the invention]
However, since the felt-like seal member has a high density of fibers and is entangled with each other, the toner that has entered the felt-like seal member rarely leaks outside through the seal member. On the contrary, the toner easily accumulates in the felt. In this case, the felt in which the toner is excessively accumulated may cause leakage due to a decrease in the sealing effect, which causes a problem in the long-term durability of the sealing effect.
[0009]
Further, in the conventional toner seal structure shown in FIG. 6, as shown in the perspective view of FIG. 7 in which the raised fiber side of the raised seal member 9a is on the upper side, flocking is performed on the base fabric 9a-3 lined with the sponge 9a-2. Since the raised fiber group 9a-1 has a hair fall direction A parallel to the rotation direction A of the developing roller 7, the toner 3 is easily taken in and moved along the hair fall direction A. However, the toner 3 leaks linearly as the developing roller 7 rotates, and the uncharged toner adheres in the form of a collar 11 to the surface of the photosensitive drum 1 facing the leaked toner. Sometimes. This adhering toner falls on the paper and soils the paper, which causes a problem. Further, in FIG. 6, the schematic positional relationship between the supply roller 6, the developing roller 7, and the photosensitive drum 1 and their rotation directions are indicated by arrows, and the raised seal member 9 a fixed to the housing (not shown) The raising side in the direction of the arrow of the raised fiber group (on the inner surface side of the raised seal member 9a) is transparent from the fixing side (front side of the drawing) (actually, the base fabric and the sponge base material are opaque, so the fixing side) The direction of hair fall is not visible). The raised seal member 9 a is pressed against the peripheral surface 8 at both ends of the developing roller 7. In the drawing, it is also shown that the toner 3 leaked as a result adheres to the collar 11 at both opposite ends of the photosensitive drum 1.
[0010]
Thus, in the conventional toner seal structure, it is necessary to increase the pressing force because the toner is relatively easily leaked. However, if the raised seal member is slidably contacted with the developing roller with a strong pressing force in order to prevent this toner leakage, a large load is applied to the driving motor for rotating the roller, so that an expensive high torque motor is required. It becomes a problem.
[0011]
The present invention has been made in view of the above points, and it is possible to use a low-torque motor with less toner leakage without applying strong pressing force to the peripheral surfaces of both ends of the developing roller. An object of the present invention is to provide an electrophotographic process unit having a toner seal structure.
[0012]
[Means for Solving the Problems]
According to the first aspect of the present invention, the object is to provide a frame in which a developing roller that conveys toner to the surface of the photoreceptor while rotating is disposed so as to face the peripheral surfaces of both ends of the roller. In an electrophotographic process unit comprising a toner seal structure, which is fixed and subjected to pressure and sliding contact with a raised sealing member comprising a raised fabric group that has been planted and previously brushed and planted on the base fabric. The assumed intersection angle between the direction of the fallen raised fiber group and the direction of rotation of the developing roller is the same as the direction of the force applied to the toner by the rotation of the raised fiber group and the roller. By setting it to be a direction including an axial moment toward the center of the electrophotographic process unit in which the raised seal member is fixed to the frame, It is made.
[0013]
According to a second aspect of the present invention, there is provided a toner seal structure in which the raised seal member in which the assumed intersection angle is set to any one of 15 to 60 degrees is fixed to a frame. A photographic process unit is preferred.
[0014]
According to the third aspect of the present invention, it is desirable to use the electrophotographic process unit according to the first or second aspect, wherein the raised fiber group is a fluorinated fiber.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the electrophotographic photoreceptor of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the examples described below as long as the gist thereof is not exceeded.
[0016]
FIG. 1 is a perspective view showing a main part of a toner seal structure used in an electrophotographic process unit according to the present invention, and FIG. 2 is a diagram showing a raised fiber of a raised seal member used in the toner seal structure according to the present invention on the upper side. FIG. 4 is a side sectional view of the toner seal structure in which the toner seal member is pressed against both ends of the developing roller in the developing unit as viewed from the axial direction, and FIG. 5 is the developing in the developing unit. FIG. 8 is an enlarged cross-sectional view of the brush seal member in the thickness direction, with the toner seal structure of the roller viewed from the top perpendicular to the roller axis.
[0017]
Note that the concept of the electrophotographic process unit in the present invention means a process unit including at least a member constituting the developing process among the above-described electrophotographic processes, so that the developing unit is of course included in the process unit. For example, a unit in which the drum unit and the developing unit are integrated is also included in the concept of the electrophotographic process unit referred to in the present invention.
[0018]
Such an electrophotographic process unit according to the present invention is substantially the same except for the schematic sectional view of the conventional electrophotographic process unit shown in FIG. The process unit for electrophotography according to the present invention will be described. The supply roller 6 has a function of supplying the toner 3 in the toner storage portion 5 to the developing roller 7 by rotation and rotates in contact with the developing roller 7 in the same direction, so that the rotation directions at the contact portion are opposite to each other. The toner 3 conveyed to the developing roller 7 is conveyed to the surface of the photosensitive drum 1 by rotation while being charged by the layer thickness regulating member on the roller 7 and develops the electrostatic latent image on the surface of the drum 1. The configuration in the case where the developing roller 7 and the supply roller 6 shown in FIG. 1 are included in the developing unit 100 and the photosensitive drum 1 belongs to the drum unit 50 may be the same except for the toner seal structure shown in FIG.
[0019]
As shown in FIG. 1, in the perspective view showing one end portion of the toner seal structure according to the present invention, the photosensitive member 1 rotating in the arrow direction and the rotation indicated by the arrow of the developing roller 7 rotating in the same direction at the contact portion. The state where the arc-shaped raised seal member 9b to be pressed against one end peripheral surface 8 of the roller 7 is separated from the pressing portion with respect to the direction is shown. In the raised seal member 9b, the raised fiber group 9b-1 provided on the inner surface side of the arc is shown in FIG. The outer surface side of the arc of the raised seal member 9b is bonded to a frame (housing) (not shown). The actual mounting state of the raised seal member 9b in the unit is shown in FIG. In this seal structure, when the toner 3 comes into contact with the raised seal member 9b in operation (during rotation of the roller), the raised fiber group 9b-1 that has been subjected to the slanting process in the oblique direction causes the toner 3 to always be a roller. 7, the moment of the force toward the direction B of the shaft 7 a, that is, the central direction of the roller is received, so that the leakage of the toner 3 from the brushed seal member 9 b is reduced to the outside, and the conventional toner seal structure described above (FIG. 6). ), The toner 3 adheres to the collar 11 at both ends of the surface of the photosensitive member 1 to eliminate the problem of image defects.
[0020]
In the raised seal member 9b shown in FIG. 1, since the state of the hair fall processing of the raised fiber group 9b-1 facing in the oblique direction C is difficult to understand, the raised seal member 9b is turned down in the raised fiber group 9b-1 in FIG. The principal part perspective view expanded and seen from the process side is shown. FIG. 2 shows 15 degrees to 60 degrees with respect to the rotation direction A of the roller 7 when the hair fall direction C of the raised fiber group 9b-1 planted or woven into the base fabric 9b-3 is pressed against the developing drum 7. It is set to be one of the angles. This angle is shown as an assumed crossing angle 7c between the arrow A and the arrow C in FIG. A known fiber material can be used as the material for the raised fibers, but in the case of a non-magnetic one-component positively charged toner, a fluorine-based polymer material is preferable in consideration of a frictional charge series by the raised fibers. The fiber length is preferably 2 to 4 mm. In the following description, it is assumed that the planted raised fibers include woven ones.
[0021]
4 is a side sectional view showing the toner seal structure according to the present invention, except for the toner seal structure, which has substantially the same sectional structure as the conventional developing unit 100 shown in FIG. FIG. 2 is an enlarged cross-sectional view of a cross section at a surface 8 and a cross section at an arbitrary position of a supply roller 6 as viewed from the direction B of the shaft 7a of the developing roller 7 described above with reference to FIG. Since the peripheral surface 8 at both ends of the developing roller 7 is rotated by receiving pressure from the raised seal member 9b according to the present invention adhered to the inside of the housing (frame body) 13 facing the peripheral surface 8 at a predetermined interval. The toner hardly leaks from the peripheral surfaces of both end portions of the developing roller 7. Reference numeral 5 denotes a toner container, reference numeral 3 denotes toner, and reference numeral 14 denotes a partition plate that separates the toner container 5 and the supply roller 6.
[0022]
FIG. 5 is a schematic cross-sectional view of the main part viewed from above (a direction orthogonal to the roller shaft 7a direction B) illustrating the toner seal structure of FIG. 5. The toner container 5, the developing roller 7, the supply roller 6 and the drum unit in the developing unit 100. The positional relationship with the edge part of the inside photoconductive drum 1 and the relationship with the both-ends peripheral surface 8 which a raising seal member presses are shown. When the toner 3 in the toner container 5 reaches the supply roller 6 beyond the partition plate 14 on the supply roller 6 side, the toner 3 is conveyed to the developing roller 7 by the rotation of the supply roller 6. When the toner 3 on the developing roller is pressed by the raised seal member 9b on the peripheral surface 8 at both ends, the direction of the fallen processing of the raised fiber group is performed so that a moment of force is applied to the toner 3 in the direction of returning to the center. Is set, toner is less likely to leak out of the developing unit.
[0023]
As shown in the cross-sectional view of the main part in FIG. 8, the raised seal member 9b is made of a plain woven fabric made of fibers of cotton, polyester, polypropylene, acrylic, polyamide, or the like as a base fabric 9b-3, and fluorine such as tetrafluoroethylene. The base fabric 9b-3 is a heat roller in which fiber fibers 9b-1 having a denier of 6 to 15 denier are piled at a pile yarn density of 40 to 80,000 yarns / (inch) ² and heated to 100 to 150 ° C. In addition, the nap is laid down by pressing in the surface direction, and further, the hair is laid down so as to have a predetermined angle with respect to the rotation direction of the roller. The method described in detail on page 3 of the above-mentioned Patent Document 7 is adopted for the method of the hair-falling process itself, except that the hair-falling process is performed so as to have a predetermined angle with respect to the rotation direction of the roller. Can do. For comparison with the present invention, FIG. 7 shows a perspective view of a conventional raised seal member 9a that has been subjected to a hair fall process as described in Patent Document 7. In this seal member 9a, the hair fall direction A is parallel to the rotation direction of the roller. Further, in the raised seal member 9a, the raised fiber group 9a-1 is planted on the base fabric 9a-3, and further, a cushion material 9a- Backed by 2.
[0024]
However, in the above-mentioned Patent Document 7, there is no description or suggestion for providing a predetermined angle with respect to the rotation direction of the roller as in the present invention. Regarding the orientation at the time of the tumbling process according to the present invention, the method of angling and declining on the basis of the weaves of the weaving yarns orthogonal to the base fabric surface, and after tumbling once parallel to the weave of the base fabric As the raised seal member according to the present invention, when cutting to a required dimension, the base fabric is cut obliquely with respect to the weave of the base fabric so that the hair fall direction is angled. There is a method of making an angle in the direction of tilt.
[0025]
On the other hand, the raised seal member 9a according to the present invention is not lined with the cushion material as described above. This is because it has been found that when a backing like a sponge is applied, the toner taken into the sponge increases with time and becomes a source of toner leakage.
[0026]
(Experimental example)
Next, the following experiment was conducted in order to confirm the effect of the raised fiber group of the raised sealing member in the toner seal structure of the process unit according to the present invention in terms of the direction of hair fall.
[0027]
The crossing angle of the 3 mm long raised fiber group (15 mg / cm ² ) made of tetrafluoroethylene woven into the cloth substrate and the rotation direction of the roller is 0 degree, 10 degrees, 15 degrees, 30 degrees , 45 °, 60 °, 75 °, 90 °, a commercial unit in which a process unit having a toner seal structure using brushed seal members (5 mm width) is changed to a low-torque motor with two-thirds of the original torque. The electrophotographic printer was remodeled, and the seal pressing force by the brushed fiber was reduced to one half of the pressing force of the original seal, and 30,000 continuous printing tests were conducted. The printed image was evaluated by the presence or absence of stains on the edge of the paper due to toner leakage. The results are shown in Table 1 below.
[0028]
[Table 1]

[0029]
From Table 1, when the crossing angle between the direction in which the raised fibers are laid down and the rotation direction of the roller is 0 degree or 90 degrees, the toner leakage is severe and the image state is very bad. Is an oblique angle in the direction according to the present invention with respect to the rotation direction of the developing roller as described above, the toner leakage is drastically reduced by the effect of the present invention. It can be said that there is no problem in view of image evaluation. Furthermore, in the crossing angle range of 60 degrees or less and 15 degrees or more, no image smear due to the toner is observed, and a favorable image is obtained, which indicates that the angle range is particularly preferable.
[0030]
【The invention's effect】
According to the present invention, the developing roller that conveys the toner to the surface of the photosensitive member while rotating is fixed to the frame disposed so as to face the peripheral surfaces of both ends of the roller, and the base cloth and the base cloth are In a process unit for electrophotography having a toner seal structure subjected to pressure and sliding contact by a raised seal member having a raised fiber group that is planted in a weave and pre-tipped, the raised fiber group that has been tumble-processed in advance The assumed crossing angle between the direction of the hair tumbling and the direction of rotation of the developing roller is an axis in which the direction of the force applied to the toner by the tumbled fiber group and the rotation of the roller is directed toward the center of the roller. Since the brushed sealing member is set to a direction including a directional moment and the electrophotographic process unit is fixed to the frame, it is strong against the peripheral surfaces of both ends of the developing roller. Without applying pressure, less likely to occur with the toner leak, it is possible to provide an electrophotographic process unit comprising a toner seal structure capable of using inexpensive low-torque motors.
[Brief description of the drawings]
FIG. 1 is a perspective view of a main part of a toner seal structure used in an electrophotographic process unit of the present invention. FIG. 2 is a perspective view of a main part of a raised seal member used in the toner seal structure according to the present invention. FIG. 4 is a side sectional view showing a toner seal structure of the developing roller in the developing unit according to the present invention. FIG. 5 is a toner of the developing roller in the developing unit according to the present invention. FIG. 6 is a schematic perspective view of a conventional toner seal structure. FIG. 7 is a perspective view of a main part of a conventional brushed seal member. FIG. 8 is a cross section of the brushed seal member according to the present invention. Figure [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Photosensitive drum 3 Toner 5 Toner accommodating part 6 Supply roller 7 Developing roller 7a Developing roller shaft 7c Crossing angle 8 of rotation direction and hair fall direction Peripheral surface 9b of both ends Brushed seal member 9b-1 Brushed fiber group 9b-3 Base fabric 13 Housing (frame)
100 Developing unit A Rotating direction of developing roller B Axing direction of developing roller C Pulling direction of raised fiber group

Claims

A developing roller that conveys the toner to the surface of the photoreceptor while rotating is fixed to a frame disposed so as to face the peripheral surfaces of both ends of the roller, and is fixed to the base cloth and the base cloth. In a process unit for electrophotography having a toner seal structure subjected to pressing and sliding contact by a raised seal member having a raised fiber group that has been subjected to a hair fall process, the direction of the fall of the raised fiber group that has been subjected to the hair fall process and the developing roller The direction of the force that the toner receives due to the fluffed raised fiber group and the rotation of the roller is a direction that includes an axial moment toward the central portion of the roller. The electrophotographic process unit is characterized in that the raised seal member is fixed to the frame.

2. The process unit for electrophotography according to claim 1, further comprising a toner seal structure in which a raised seal member in which the assumed intersection angle is set to any one of 15 degrees to 60 degrees is fixed to a frame.

The electrophotographic process unit according to claim 1, wherein the raised fiber group is a fluorine-based fiber.