JP4623922B2 - Image forming apparatus - Google Patents

Description

【００５９】
回転方向をカウンター方向に切り替える条件は前記実施形態７および１５のようにして、クリーニングブラシを駆動しているモーターの起動電流値を所定通紙枚数（例えば５００枚）時毎に検知し、残留トナー入力要の基準値（図３）あるいは閾値（図４）であるかどうかを判断し、前記クリーニングブラシをカウンター方向の回転に切り替える場合のみ、前記残留トナー入力要の連続検出回数に応じて、クリーニングブラシの回転数を制御してフィルミング物質を除去するようにする。
例えば、前記表１のようにモーター回転数倍率を制御した場合、ジョブ枚数に対する像担持体表面削れ量、ジョブ枚数に対する消費トナー重量の関係は、それぞれ図８、図９のようになる。回転数倍率制御を行うことにより、実施形態７および１５の動作の時よりも像担持体表面削れ量は減少し、像担持体高寿命化に繋がるほか、トナー消費重量も減少し、効率よく像担持体表面に付着したフィルミング物質が除去できる。
【００６０】
実施形態１７の実施の形態を以下に示す。
前記実施形態１〜１６において、トナー入力は必要最小限に制御されて行われるが、入力された画像域外での残留トナーはいずれにしても消費されることになるのでトナーイールドが低下する。
このため、前記画像形成装置のクリーニング手段（クリーニングブラシ、クリーニングブレードを有する）にトナーリサイクル手段を設けることにより、トナー消費量の低減を図るようにした。図１０にトナーリサイクル手段を備えた画像形成装置の部分概略模式図を示す。
【００６１】
図１０において画像形成装置には、クリーニング手段２４に装着されたクリーニングブラシ２１、クリーニングブレード２２および回収コイル２３によって、像担持体２０上から回収されたトナーを、現像フィルタ２６、搬送スクリュー２７、攪拌ローラ２８、パドルローラ２９、スリーブ３０、３１等の機構を内臓した現像手段３２に搬送する移送機構（例えばスクリューコンベア等）を有するトナーリサイクル手段３３が設けられている。なお、トナーリサイクル手段３３には、トナーの分級機能などが含まれていてもよい。
このようなトナーリサイクル手段３３によって、回収された残留トナーをリサイクルし、再使用することができるため無駄な消費が避けられ、トナーイールドの低下を抑制して像担持体２０鏡面のフィルミング物質の除去を実施することが可能となる。
【００６２】
【実施例】
以下、実施例により本発明を更に詳細に説明する。ただし、本発明はなんら実施例に限定されるものではない。なお、実施例１〜３，８〜１０は参考例である。
【００６３】
実施例１（前記実施形態１および２に係る実施例）
本実施例では、前記図１に示した各手段を有し、前記図１０の部分概略模式図に示す構成からなる画像形成装置（リコー製Ｉｍａｇｉｏ ＭＦ８５７０を改造した装置）を用いてトナー入力量に関する評価試験を行った。
なお、本実施例で用いた図１０に示す像担持体２０には、感光耐表層にオーバーコートを施し、耐磨耗性を向上した直径１００ｍｍの感光体を使用し、クリーニング手段２４に装備のクリーニングブラシ２１としては、下記表２に示す諸元のものを用いた。
【００６４】
【表２】

【００６５】
上記表２に示した諸元のクリーニングブラシ２１による評価の結果、スタート時、すなわち像流れの原因となるフィルミング物質が像担持体２０に付着していない状態でのクリーニングブラシ２１起動時の静トルク値は、０．４０８ｋｇｆ・ｃｍ（０．０４０Ｎ・ｍ）であった。一方、転写動作によってフィルミング物質が付着した時の静トルク値は、０．３２３ｋｇｆ・ｃｍ（０．０３２Ｎ・ｍ）であり、前未付着時と比べて０．０８５ｋｇｆ・ｃｍ（０．００８Ｎ・ｍ）の変化を生じることが分かった。
【００６６】
上記静トルク値の変化に対するクリーニングブラシ２１の起動時の駆動電流値（起動電流値）を測定した結果、図１１に示すような関係が得られた。図１１から明らかなように、静トルク値と起動電流値は比例関係にあり、このことから静トルク値の変化を起動電流値に変換して捉えることができ、この起動電流値の検知によってトナー入力の判断、制御が可能であることが確認された。
【００６７】
また、上記図１１の関係からフィルミングしない場合の起動電流値０・３８と、フィルミングした場合の起動電流値０．３４との平均値０．３６を求め、これを基準値に設定して（図１２参照）、転写紙の通紙５００枚毎にフィルミング物質の付着状態を起動電流値検知によって行いながら、トナー入力量の制御・供給をジョブ終了時に行ったところ、像流れなどの発生率が低減した高画質の画像を連続して得ることができた。
なお、上記トナーの入力制御は、検知した起動電流値が基準値と比較して、大きい場合はトナー入力を行わず、基準値と比較して小さい場合に通常の半分の光量で書きこみ、幅３００ｍｍ、長さ９０ｍｍ、トナー量約０．５ｍｇ／ｃｍ^２の条件でトナーの入力をジョブ終了時に行った。
【００６８】
実施例２（前記実施形態３に係る実施例）
上記ジョブ後終了後のトナー入力に代えて連続通紙の通紙間にトナー入力を行い、かつ通紙間に入力されたトナーが転写ベルトユニット（前記図１の転写ベルトユニット９に相当）を通過する時は、転写ベルトユニットが像担持体（前記図１の像担持体１に相当）から離れるように制御した他は、実施例１と同じようにして前記基準値（０．３６Ａ）により転写紙の通紙５００枚毎に起動電流を検知しながらコピーを実行した。その結果、更に効率良くフィルミング物質の除去ができ、画像流れのない高品質の画像が得られた。
【００６９】
実施例３（前記実施形態４に係る実施例）
実施例２において、通紙間に入力されたトナーが転写ベルトユニットを通過する時は、転写ベルトユニットが像担持体から「離れる」ように（転写状態が解除されるように）制御したのに代えて、転写ベルトユニットが像担持体から「離れず」に転写状態が維持されるようにしつつ、連続通紙のまま前記転写電流値を低下させて転写残トナー量を増やす方法とした他は、実施例２と同じようにして転写紙の通紙５００枚毎に起動電流を検知しながらコピーを実行した。その結果、更に時間消費を無駄にすることなく効率良くフィルミング物質の除去ができ、画像流れのない高品質の画像が得られた。
【００７０】
実施例４（前記実施形態５および１３に係る実施例）
通常の画像形成における動作条件として、現像ポテンシャル：約５００Ｖ、転写電流値：１２０μＡに設定した画像形成装置で、トナー入力の制御・供給を要する場合み、現像ポテンシャルを６００Ｖに上げると共に、転写電流を５０μＡに下げて通紙状態のままで残留トナーを供給するように制御した。得られた転写紙上の画像濃度は約１．４であり、転写濃度が低下するようなことはなく、通常と同様に良好な画像が得られた。また、フィルミング物質も効率的に除去することができた。
【００７１】
実施例５（前記実施形態６および１４に係る実施例）
フィルミング物質が強固に固着して除去が難しい条件（画像面積率６％チャート使用）でコピーを行い、前記クリーニングブラシ加圧機構を設けた場合（有り）と、設けない場合（無し）について、それぞれトナー消費量を評価した。得られたジョブ枚数（通紙枚数）と消費トナー重量との関係を図１３に示す。
図１３に示すようにジョブ約１０００００枚で像担持体表面にフィルミング物質が付着し始め、クリーニングブラシ加圧機構無しの場合には、１０００００枚以降において通常のジョブでのトナー消費量に加えてさらに補給分のトナーが消費されている。
クリーニング加圧機構有りの場合には、クリーニング加圧機構無しに較べてトナー補給回数が少なくなりトナー補給量も低減し、しかもフィルミング物質も除去されている。ジョブ３０００００枚ではトナー消費量は約９００ｇも低減されることが分かった。すなわち、必要最低限のトナー消費でフィルミング物質を通常よりもより多く除去することができた。
【００７２】
実施例６（前記実施形態７および１５に係る実施例）
前記実施の形態７および１５におけるクリーニングブラシの回転方向を切り替え可能とした場合について評価した。
図１４にクリーニングブラシの回転方向をトレーリング方向に固定した場合、カウンター方向に固定した場合、および前記のように検知起動電流値変動が残留トナーの入力を要しない場合と入力を要する場合とにおいて、トレーリング方向とするかあるいはカウンター方向の回転方向とするかそれぞれで切り替えて制御した時（本発明）のジョブ枚数に対する像担持体表面の削れ量を示す。本発明の動作を行うことにより、像担持体の削れ量はトレーリング方向とカウンター方向のほぼ中間値となった。本発明の制御により、効率よく像担持体表面に付着したフィルミング物質を除去することができた。また、クリーニングブラシを像担持体に対しカウンター方向に回転した時よりも像担持体表面の削れ量が減少し、像担持体高寿命化にも繋がった。
【００７３】
実施例７（前記実施形態８および１６に係る実施例）
前記実施例の形態において示した表１のようにモーター回転数倍率を制御した結果、像担持体表面削れ量はジョブ３０００００枚では０．２μｍ減少し、トナー消費重量は約９５０ｇ減少した。本発明により、効率良くより少ないトナー消費で像担持体表面に付着したフィルミング物質を除去し、かつ、実施形態７，１５の動作よりも像担持体表面の削れ量が減少し、像担持体高寿命化にも繋がった。
【００７４】
実施例８（前記実施形態９および１０に係る実施例）
図１５に０〜３００Ｋ枚までのコピー経時における転写画像の像流れが発生しない場合と、像流れが発生する場合とにそれぞれ対応する起動電流値の変化を調べた結果を示す。
この試験結果から、通紙枚数（コピー枚数）と起動電流値とをそれぞれ下記表３に示す閾値区分に分けて、トナー入力量を設定した。この設定値を基準にして転写紙の通紙５００枚毎に起動電流を検値しながらコピーを実行した結果、予めトナーの消費効率が小となるようにクリーニングブラシへの残留トナー入力量が設定されているため、必要以上のトナーを消費することなく、効率良くフィルミング物質の除去ができ、画像流れのない高品質の画像が得られた。なお、上記トナー入力は通常の半分の光量で約０．５ｍｇ／ｃｍ^２のトナー入力をジョブ終了時に行った。
【００７５】
【表３】

【００７６】
実施例９（前記実施形態１１に係る実施例）
上記ジョブ後終了後のトナー入力に代えて連続通紙の通紙間にトナー入力を行い、かつ通紙間に入力されたトナーが転写ベルトユニット（前記図１の転写ベルトユニット９に相当）を通過する時は、転写ベルトユニットが像担持体（前記図１の像担持体１に相当）から離れるように制御した他は、実施例４と同じようにして前記基準値（０．３６Ａ）により転写紙の通紙５００枚毎に起動電流を検知しながらコピーを実行した。その結果、必要以上のトナーを消費することなく、更に効率良くフィルミング物質の除去ができ、画像流れのない高品質の画像が得られた。
【００７７】
実施例１０（前記実施形態１２に係る実施例）
実施例９において、通紙間に入力されたトナーが転写ベルトユニットを通過する時は、転写ベルトユニットが像担持体から「離れる」ように（転写状態が解除されるように）制御したのに代えて、転写ベルトユニットが像担持体から「離れず」に転写状態が維持されるようにしつつ、連続通紙のまま前記転写電流値を低下させて転写残トナー量を増やす方法とした他は、実施例９と同じようにして転写紙の通紙５００枚毎に起動電流を検知しながらコピーを実行した。その結果、必要以上のトナーを消費することなく、更に無駄な時間を費やすことなく更に効率良くフィルミング物質の除去ができ、画像流れのない高品質の画像が得られた。
【００７８】
実施例１１（前記実施形態１７に係る実施例）
前記実施形態１〜１６においては、フィルミング物質の除去に際して画像域外でのトナー入力量を増加させるものであるため、基本的にはトナーの消費を伴うものであるが、従来単に廃トナーとしていたものを再利用したため、トナーリサイクル手段３３を作動させた場合には非作動の場合に対してトナー消費量が低減し、トナーイールドの低下を招くことなくフィルミング物質の除去が可能になった。
【００７９】
【発明の効果】
請求項１の画像形成装置によれば、クリーニングブラシ駆動モータの静トルク値に連動して変化する起動電流値を検知し、必要に応じて残留トナー入力量を増やす制御を行うことにより、像担時体に付着したフィルミング物質が除去されるため、像流れ、トナー像のかすれ、あるいは地汚れ等の発生が解消されて不具合のない安定した画像が得られる。また、転写状態解除のために要する転写動作が簡便化され、無駄な時間を費やすことなく必要最低限の動作によって像担持体に付着したフィルミング物質が除去され、連続通紙でも像流れ等の不具合が発生せずに画像濃度を維持した高品位の画像が安定して得られる。
【００８０】
請求項２の画像形成装置によれば、像担持体表面のフィルミング物質を通常よりも多く、早く除去することにより、連続通紙でも像流れ等の不具合が発生せずに高品位の画像が安定して得られる。
【００８１】
請求項３の画像形成装置によれば、像担持体表面の研磨を低減し、かつ必要最小限の残留トナー入力で効率的にフィルミング物質を除去することができるため、連続通紙でも像流れ等の不具合が発生せずに高品位の画像が安定して得られる。
【００８２】
請求項４の画像形成装置によれば、像担持体表面の研磨を低減すると共に、効率的にフィルミング物質を除去することができるため、連続通紙でも像流れ等の不具合が発生せずに高品位の画像が安定して得られる。
【００８３】
請求項５の画像形成装置によれば、画像形成装置に残留トナーのリサイクル手段を備えることによってトナーの消費量を低減し、トナーイールドの低下を招くことなくフィルミング物質を除去することができ、更に無駄を省くことが可能となる。
【図面の簡単な説明】
【図１】実施の形態において本発明に係る画像形成装置を説明するための主要構成例を示す概略模式図である。
【図２】実施の形態において本発明のトナー入力制御に適用するクリーニングブラシ駆動モータの起動電流値と静トルク値との関係を模式的に示す概念図である。
【図３】実施の形態においてフィルミングした場合としない場合の起動電流値から基準値を設定してトナー入力の制御をする関係を模式的に示す概念図である。
【図４】実施の形態において像流れの発生、非発生をパラメータとし通紙累積枚数と起動電流値とを閾値化してトナー入力量を設定する一例を示す概念図である。
【図５】実施の形態において転写電流値と現像ポテンシャルを制御する場合の像担持体上トナー量と転写紙上画像濃度との関係を示す図である。
【図６】実施の形態において転写電流値と現像ポテンシャルを制御する場合の現像ポテンシャルと像担持体上トナー量との関係を示す図である。
【図７】実施の形態において像担持体に対するクリーニングブラシの圧接力を制御するクリーニングブラシ加圧機構を説明するための概略構成を示す模式図である。
【図８】実施の形態においてクリーニングブラシの回転方向および回転数を制御する場合のジョブ枚数と像担持体削れ量との関係を示す図である。
【図９】実施の形態においてクリーニングブラシの回転方向および回転数を制御する場合のジョブ枚数と消費トナー重量との関係を示す図である。
【図１０】実施の形態および実施例におけるトナーリサイクル手段を備えた画像形成装置（リコー製Ｉｍａｇｉｏ ＭＦ８５７０を改造）の部分概略模式図である。
【図１１】本発明の実施例における起動電流値と静トルク値との関係を示す図である。
【図１２】本発明の実施例におけるトナー入力制御のための基準値をフィルミングした場合としない場合の起動電流値から設定する関係を示す図である。
【図１３】本発明の実施例におけるクリーニングブラシを圧接した場合としない場合のジョブ枚数と消費トナー重量との関係を示す図である。
【図１４】本発明の実施例におけるクリーニングブラシの回転方向を制御した場合のジョブ枚数と像担持体削れ量との関係を示す図である。
【図１５】本発明の実施例における像流れ発生時と非発生時の起動電流値と累積通紙枚数との関係を示す図である。
【符号の説明】
１ 像担持体
２ 帯電手段
３ 現像手段
４ 転写手段
５ クリーニングブラシ
６ クリーニングブレード
７ クリーニング手段
８ 除電手段
９ 転写ベルトユニット
２０ 像担持体
２１ クリーニングブラシ
２２ クリーニングブレード
２３ 回収コイル
２４ クリーニング手段
２６ 現像フィルタ
２７ 搬送スクリュー
２８ 攪拌ローラ
２９ パドルローラ
３０ スリーブ
３１ スリーブ
３２ 現像手段
３３ トナーリサイクル手段
４１ 像担持体
４２ クリーニングブラシ
４３ 揺動腕
４４ 加圧スプリング
４５ 加圧ソレノイド[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an image forming apparatus having means for cleaning residual toner on an image carrier with a cleaning brush, and more particularly to an image forming apparatus having a function of removing a filming substance formed on an image carrier.
[0002]
[Prior art]
  Conventionally, an image forming apparatus of a type in which an electrostatic latent image is formed on an image carrier and visualized with toner, and the toner image is transferred to a transfer material (transfer paper) and the image carrier is repeatedly used. Is well known. Such an image forming apparatus is configured as, for example, an electrophotographic copying machine, a printer, or a facsimile. By the way, in this type of image forming apparatus, NO_xIn other words, a so-called filming phenomenon occurs in which a nitric acid compound, a toner wax (WAX) component, paper dust, or the like adheres to the surface of the image carrier. When this filming phenomenon occurs, the toner image becomes blurred, the image flows, the background is stained, and the like, leading to a deterioration in the image quality of the toner image.
[0003]
  Many methods for removing this filming have been proposed. There are known methods such as removing filming while polishing the surface of the image carrier with an abrasive or a polishing brush, or scraping filming by pressing a blade or brush against the image carrier. It is well known that when a blade or brush is brought into pressure contact with an image carrier and the image carrier is polished, the ability to remove filming is improved by using toner.
  That is, when the image area ratio is low, filming on the image carrier is easy. On the other hand, when the toner input amount is large, the filming material is scraped off by acting as a toner abrasive and a cleaning effect is exhibited.
[0004]
  As a method for utilizing such an effect, a method for managing the humidity and temperature affecting the generation of filming, that is, used for polishing and rubbing according to the temperature and humidity sensor signals provided in the electrophotographic apparatus. A method for controlling the toner amount and time has been proposed (Japanese Patent Laid-Open No. 2002-014589). However, this method has the disadvantage of increasing the cost because each sensor must be equipped.
[0005]
  Further, when polishing the image carrier by pressing the cleaning brush against the image carrier, it has been known that the filming removal capability is improved by rotating the cleaning brush in the counter direction with respect to the moving direction of the image carrier. It has been. However, there is a problem that the life of the image carrier is shortened due to wear due to pressure contact. On the other hand, when the cleaning brush is rotated in the trailing direction with respect to the image carrier, the life is increased, but the polishing ability is lowered. Therefore, there is a demand for an improvement in cleaning conditions for the cleaning brush that can cope with a long life of the image carrier.
[0006]
  In order to remove the filming material on the image carrier, cleaning is performed for each predetermined number of copies by a cleaning brush provided at a position around the image carrier and pressed against the image carrier by a support mechanism movable. A method has been proposed (Japanese Patent Laid-Open No. 5-80683). However, this method cannot detect how much filming material has adhered to the image carrier and cannot determine whether cleaning is necessary or not. There is a problem that the life of the body is reduced because the body surface is shaved by pressure welding.
[0007]
[Problems to be solved by the invention]
  The present invention has been made in view of the above problems, and the object thereof is to perform filming material removal by performing the minimum necessary toner input and the minimum necessary operation, and image flow, It is another object of the present invention to provide an image forming apparatus that is free from toner image fading or background smearing and that provides excellent image quality.
[0008]
[Means for Solving the Problems]
  In order to solve the above problems, an image forming apparatus having means for cleaning residual toner on an image carrier with a motor-driven cleaning brush according to the present invention is provided with a cleaning brush in conjunction with fluctuations in starting current value.To supplyResidual tonerofControl is performed to increase the amount (residual toner input amount), and the filming material formed on the image carrier when a predetermined number of sheets of transfer paper passes (number of copies) is supplied with the minimum necessary toner (also referred to as input). By providing the function of removing with the minimum necessary operation, it is possible to prevent the occurrence of image flow, toner image fading, background stains, etc., and to realize a toner image with excellent image quality. Hereinafter, the present invention will be specifically described.
[0009]
  The invention according to claim 1 includes an image carrier made of a rotating photoreceptor, and charging means for charging the image carrier, and exposing the charged image carrier to the image carrier. An exposure unit that forms an electrostatic latent image, and a toner that is supplied to the image carrier and development that is a difference between a charging potential of the charging unit on the image carrier and a potential of the electrostatic latent image A developing unit that develops a toner image corresponding to the potential; a transfer unit that conveys the transfer paper and applies a charge to the transfer paper to transfer the toner image on the image carrier; and after the transfer to the transfer paper Cleaning means for removing residual toner, which is toner remaining on the image carrier, by at least a cleaning brush that is driven by a drive motor, on the image carrier in this order in the rotation direction of the image carrier. In an image forming device, When a predetermined number of sheets pass, the starting current value of the drive motor is between the starting current value when the filming material adheres to the image carrier and the starting current value when the filming material does not adhere. If it is larger than the standard value,in frontWhen control for increasing the residual toner input amount, which is the amount of residual toner supplied to the cleaning means, is not performed, and the starting current value of the drive motor is smaller than the reference value,in frontIt has a function of increasing the residual toner input amount and removing a filming substance formed on the image carrier. The control of increasing the residual toner input amount is performed by the transfer means on the transfer paper. While maintaining the transfer state in which the toner image on the carrier is transferred, control is performed to reduce the transfer current value related to the charge application to the transfer paper, and the development is performed so that the image density of the transfer paper does not decrease. An image forming apparatus that controls a potential.
[0010]
  The image forming apparatus according to claim 1, wherein a predetermined number of sheets to be transferred (the number of copies) according to the necessity of the transfer paper in conjunction with a starting current value that changes in response to a change in the static torque value of the cleaning brush drive motor.)TimeBy controlling to increase the residual toner input amount, the filming material adhering to the image bearing member is removed, so that the occurrence of image flow, toner image fading, background smearing, etc. is eliminated, and there is no problem. A stable image can be obtained.
  Note that simply lowering the transfer current value and increasing the amount of residual toner on the image carrier may be inconvenient because the transfer efficiency tends to decrease and the image density tends to decrease. For this reason, in the image forming apparatus according to the first aspect, by controlling the development potential, that is, by increasing the control potential, the amount of toner supplied to the image carrier increases, the transfer current value at the time of transfer decreases, and the transfer efficiency decreases. However, the image density can be maintained. In addition, the filming material adhering to the image carrier is removed by the minimum necessary operation without spending the time required to cancel the transfer state, the transfer operation is simplified, and the image flow etc. High-quality images can be stably obtained without any defects.
[0011]
  Also,Control to increase the residual toner input amount at the end of the jobAboveTranscription meansAboveToner on image carrierimageTheOn transfer paperThe image forming apparatus according to claim 1, wherein the transfer state, which is a transfer state, is canceled.May be.
[0012]
  According to thisSince the time when the job is finished, the transfer state is canceled, that is, transfer of the transfer paper by the transfer unit is stopped, and the electric field applied so that the toner on the image carrier is copied onto the transfer paper is turned off. The transfer current does not flow. The transfer means is separated from the image carrier. In the transfer state, a charge is applied to the transfer paper by the transfer current of the transfer means, and the toner on the image carrier is electrostatically copied onto the transfer paper.
  In the environment where the transfer state is released as described above, there is no toner movement to the transfer paper, and all the input toner is directly used for cleaning and the filming substance is removed. Thereby, a high quality image is obtained.
[0013]
  Also,Control to increase the residual toner input amount,AboveBetween transfer paper passesThe aboveTranscription meansAboveOn transfer paperAboveToner on image carrierimageThe image forming apparatus according to claim 1, wherein the transfer state, which is a state in which the toner is transferred, is canceled.May be.
[0014]
  According to this, Control to increase the amount of residual toner input between consecutive transfer sheets, etc. during the continuous sheet passing (until the next transfer sheet is conveyed for each transfer sheet that is sequentially conveyed: when the conveyed sheet is not transported) Therefore, the filming substance can be removed by effectively using time. As a result, a high-quality image that does not cause problems such as image flow even in continuous paper feeding can be stably obtained.
[0015]
  Also, Control to increase the residual toner input amountAs aboveTranscription meansAboveOn transfer paperAboveToner on image carrierimageControl is performed to reduce the transfer current value related to the charge application to the transfer paper while maintaining the transfer state, which is the state to transfer the toner.And control the transfer current value from the high-voltage power supply, that is, control the transfer current value to lower and transfer efficiency to increase the residual toner on the image carrier, while maintaining the transfer state to the transfer paper Residual toner is supplied to the cleaning means (also referred to as residual toner input). In the state where the transfer paper is conveyed by the transfer means and the transfer current flows so that the toner on the image bearing member is copied onto the transfer paper (electric field on state), the residual toner is kept passing through the transfer paper continuously. Therefore, the filming substance adhering to the image carrier is removed by a necessary minimum operation without consuming unnecessary time required for releasing the transfer state. As a result, the transfer operation is simplified, and high-quality images can be stably obtained without causing problems such as image flow even with continuous paper feeding.
[0016]
  Claim2According to the invention, the pressing force of the cleaning brush against the image carrier is variable, and the starting current value of the drive motor for each predetermined number of passing sheets of transfer paper isAboveWhen the case where the residual toner needs to be supplied to the cleaning means is smaller than the reference value, the pressure contact force is controlled so as to increase according to the number of times of continuous control for increasing the residual toner input amount. The image forming apparatus according to claim 1, wherein the filming substance firmly fixed is removed by performing control to increase a residual toner input amount.
[0017]
  Claim2In this image forming apparatus, when the filming substance is firmly fixed, the starting current value of the drive motor for each predetermined number of sheets passed isAboveIn order to avoid such a problem, the pressure contact force of the cleaning brush with respect to the image carrier can be varied. (A cleaning brush pressure mechanism is provided).
  For example, residual toner supply is requiredAboveWhen the reference value is detected, control is performed to increase the pressure contact force by increasing the amount of biting of the cleaning brush into the image carrier by the cleaning brush pressurizing mechanism simultaneously with the supply of residual toner after a predetermined predetermined number of times (for example, three times). By removing more filming material on the surface of the image carrier faster than usual, a high-quality image can be stably obtained without causing problems such as image flow even with continuous paper feeding.
[0018]
  Claim3The invention according toDrivemotorByDriveDoThe rotation direction of the cleaning brush can be switched to the trailing direction or the counter direction with respect to the moving direction of the image carrier.AboveBased on the result of comparison with the reference value, the rotation is controlled in the trailing direction when supply of residual toner to the cleaning unit is not required, and in the counter direction when supply of residual toner to the cleaning unit is required. 2. The image forming apparatus according to claim 1, wherein the filming substance is removed.
[0019]
  Claim3In the case of the image forming apparatus, the cleaning brush rotation direction with respect to the moving direction of the image carrier is different from that in the case where supply of residual toner is not required and supply is required, that is, depending on the adhesion state of the filming substance. By rotating in the ring direction or rotating in the counter direction, polishing of the surface of the image carrier can be reduced, and the filming substance can be efficiently removed with a minimum amount of toner supply. However, high-quality images can be stably obtained without causing problems such as image flow.
[0020]
  Claim4In the invention according to the present invention, only when the cleaning brush is switched to the counter direction rotation, the cleaning brush rotation number is increased and controlled according to the continuous number of times of performing the control to increase the residual toner input amount, and the filming substance is removed. Claims made to do so3The image forming apparatus described in the above.
[0021]
  Claim4In this image forming apparatus, only when the cleaning brush is switched to the counter rotation, the cleaning is performed according to the number of continuous times of increasing the residual toner input amount, that is, when the filming substance is firmly attached. The brush rotation speed was increased and controlled to speed up removal.
  As a result, the polishing of the surface of the image carrier can be reduced and the filming substance can be removed efficiently, so that a high-quality image can be stabilized without causing problems such as image flow even in continuous paper feeding. can get.
[0028]
  Claim5The invention according to claim 1 further comprises a recycling means for collecting and reusing the residual toner.4The image forming apparatus according to any one of the above.
[0029]
  Claim5In the image forming apparatus described in the above, it is possible to reduce the toner consumption by providing the residual toner recycling means, to remove the filming substance without causing a decrease in toner yield, and to further reduce waste. It becomes possible.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of the present invention will be described below.
  The present invention will be further described with reference to a schematic diagram showing a main configuration as an example of the image forming apparatus of the present invention in FIG. Note that the image forming apparatus of the present invention is not limited to the following embodiments, and can take other configurations without departing from the gist of the present invention.
[0031]
  The image forming apparatus according to the present invention includes a charging unit 2, a developing unit 3, a transfer unit 4, and a cleaning brush 5 driven by a motor (not shown) around an image carrier 1 formed of a photosensitive member as illustrated in FIG. And a cleaning means 7 having a cleaning blade 6 and a discharging means 8 are provided.
[0032]
  That is, an electrostatic latent image is formed by an exposure unit (not shown) on the image carrier 1 charged by the charging unit 2, and the toner image obtained by developing by the developing unit 3 is transferred to the transfer paper by the transfer unit 4. An image is formed by fixing. The developing toner is supplied from the developing means 3 in accordance with the difference between the charging potential on the image carrier 1 and the potential of the electrostatic latent image formed by exposure with laser light, that is, the developing potential (potential), and then transferred. The means 4 applies an electric field to the transferred transfer paper so that the toner on the image carrier 1 is copied onto the transfer paper, that is, the transfer paper is charged by the transfer current, and electrostatically the image carrier. The toner on 1 is copied onto the transfer paper. The print density is affected by the development potential and the transfer current.
  During this image formation, toner remaining on the image carrier 1, so-called residual toner, is removed and cleaned by a cleaning means 7 having a motor-driven cleaning brush 5 and a cleaning blade 6 that rub the surface of the image carrier 1. Is done. Then, after cleaning, the image carrier 1 is neutralized by the neutralization means 8, and a preparation state for the next charging is completed.
[0033]
  In the image formation, filming substances such as wax (WAX) component contained in the toner, cellulose (such as paper powder) of transfer paper, NO_xNitric acid-based compounds or the like adhere (filming phenomenon), and the surface friction coefficient of the image carrier 1 decreases. That is, the surface friction coefficient of the image carrier 1 to which the filming substance is attached is reduced as compared with the surface friction coefficient of the image carrier 1 to which the filming substance is not attached.
[0034]
  When the surface friction coefficient of the image carrier 1 is lowered, the torque value of the cleaning brush 5 that is rotationally driven by a motor that rubs the surface of the image carrier 1 is also lowered. The change in the surface friction coefficient, that is, the torque value (static torque value) of the cleaning brush 5 at the start reflects the filming state, and this torque value is the material, thickness, and length of the brush of the cleaning brush 5. Depending on the density and the like, the starting current value of the drive motor of the cleaning brush 5 changes in conjunction with the amount of change in the static torque value as shown in the conceptual diagram of FIG.
[0035]
  From the relationship shown in FIG. 2, when the starting current value of the cleaning brush 5 at the start is detected and it is determined that the filming state is progressing, control is performed to increase the amount of toner input having a polishing function. Thus, it is possible to remove the filming substance on the surface of the image carrier 1.
[0036]
  EmbodimentIn order to input toner to the image carrier 1 in accordance with the toner input amount control / supply operation in 1 and 2, that is, the starting current value of the brush drive motor that drives the cleaning brush 5 alone, the following is performed. Do.
  For example, as shown in the conceptual diagram of FIG. 3, first, when the activation current value of the cleaning brush 5 with respect to the image carrier 1 does not film (current value: aA) and when filming occurs (current value: bA). An intermediate value (current value: (a + b) / 2) is set as a reference value. The toner input is controlled by determining whether the detected starting current value is large or small around this reference value.
[0037]
  That is, the current value at the time of starting the drive motor of the cleaning brush 5 is detected before starting the predetermined job, and if the detected value is larger than the reference value (a + b) / 2, toner input is not performed. If the detected value is smaller than the reference value, it is determined that filming is about to occur, and the developing unit 3 drops the amount of toner input pattern on the image carrier 1 (half the normal light amount). Control is performed to increase the amount of toner input to the writing and cleaning means 7, and toner input is performed at the end of the job.
  Since the toner input is performed at the end of the job, the transfer state is released, that is, the transfer unit 4 stops transporting the transfer paper, and no transfer current flows (electric field off state) (transfer unit). The developed toner on the image carrier 1 is directly input to the cleaning means 7 (4 is away from the image carrier 1).
[0038]
  By increasing the amount of toner input to the image carrier 1, the amount of toner input to the cleaning brush 5 and the cleaning blade 6 increases, and the toner acts as an abrasive to scrape off the filming material attached to the image carrier 1. be able to. In this way, the filming substance that causes the image flow is scraped off, so that high-quality image formation can be continued.
The start-up current detection and toner input operations are performed as necessary, but can be performed for each predetermined number of transfer sheets (for example, about 500 sheets).
[0039]
  Next, the aboveEmbodimentIn 1 and 2, the toner supply is controlled in consideration of the case where the cleaning brush has changed over time.EmbodimentEmbodiments 9 and 10 are shown below.
  If the surface of the image carrier 1 is rubbed with the motor-driven cleaning brush 5 and the residual toner is removed repeatedly, the brush may fall over time. When such a change over time causes the brush to fall down and the starting current value decreases, it is mistakenly recognized that filming has occurred by detecting this starting current value decrease, and filming has occurred. However, there is a problem that toner input is executed despite the absence.
[0040]
  If you do not consider the change in starting current over time (for example, the effect of brush fall, etc.)EmbodimentThe average value of the starting current values when filming occurs and when filming does not occur as shown in FIG. 1 is used as a reference value (see FIG. 3), and toner input is executed or not executed with this reference value as a boundary. However, in consideration of brush falling, it is necessary to devise toner input from the viewpoint of reducing toner consumption (consumption efficiency is low).
[0041]
  That is, from the above viewpoint, the remaining toner input amount to the cleaning brush is set by thresholding the cumulative number of transfer paper sheets and the starting current value so that the toner consumption is small (consumption efficiency is small) in advance. The toner input amount is controlled and supplied based on this set value, and the filming substance is efficiently removed without consuming more toner than necessary.
[0042]
  The conceptual diagram of FIG. 4 shows the relationship between the change in the starting current value associated with the accumulation of the number of sheets of transfer paper (number of copies) and the occurrence of image flow (corresponding to filming) or non-occurrence.
  In FIG. 4, the toner input amount (mg) is, for example, the image flow for each of the accumulated transfer sheet number x, y, z (K sheets) and the starting current values m, n, s (A) that are thresholded. According to the occurrence and non-occurrence, A, B, C, and D (mg) are set, respectively, and the toner input amount is controlled and supplied according to the set value according to each detected starting current value. By such control, cleaning can be performed with a minimum amount of toner supply without misidentifying the starting current value that decreases with the change in wear over time as filming substance adhesion. Note that the threshold classification shown in FIG. 4 is an example, and can be arbitrarily set without departing from the gist of the present invention.
[0043]
  The toner input operation described above is performed as follows.
  That is, when it is determined that the toner input is performed on the basis of the setting conditions for the number of sheets to be passed and the threshold value of the starting current shown in FIG. The toner input is performed at the end of the job. Since the toner input is performed at the end of the job, the transfer unit 4 is in a state in which the transfer state is released, and thus the developed toner on the image carrier 1 is directly input to the cleaning unit 7.
  Further, since the toner input amount is set to be different depending on the threshold value, the toner input is performed by changing the toner input area on the image carrier 1.
[0044]
  As an example, when the toner input amount is set to 110 mg, writing is performed with a light amount half of a normal amount, and the image carrier 1 has, for example, a width of 300 mm, a length of 73 mm, and a toner amount of about 0.5 mg / cm.²Input after the job under the conditions. Such activation current detection / toner input operation is performed with an appropriate number of sheets to be passed (the number of copies). For example, by performing the operation every about 500 sheets, the surface of the image carrier 1 is consumed without excessive consumption of toner. It is possible to remove the filmed material.
[0045]
  EmbodimentEmbodiments 3 and 11 are shown below.
  SaidEmbodimentIn the operations in 1, 2, 9, and 10, when the residual toner input is controlled / supplied by detecting the starting current value, if toner input is performed after the job, it causes trouble in continuous paper feeding and the work efficiency is poor. There is a case.
  Therefore, as a toner input method, as described above, the transfer paper is sequentially transported by the transfer means 4 and the next transfer paper is transported when the transfer paper is not transported (between paper passing). As a result, work efficiency was improved. In this case, when the toner input between the sheets passes through the transfer belt unit 9 provided in the transfer means 4 shown in FIG. 1, the transfer state is controlled so as to cancel the transfer state (the transfer belt unit 9 is an image). Away from the carrier 1). At that time, writing is performed with a normal light amount (for example, about 1 mg / cm within 10 mm within the width of the maximum transfer paper that can be passed with a width of 300 mm).²The input is sequentially performed between the first sheet and the next conveyed sheet (between sheets). In this case, the amount of toner input during one paper pass is 30 mg.
[0046]
  In the above case, taking FIG. 4 as an example, if A = 120 mg, B = 150 mg, C = 180 mg, and D = 210 mg, the toner input amount changes from 120 to 210 mg depending on the threshold value of the number of copies and the starting current value. When the toner input amount is 30 mg between one paper pass, the number of times of input to the paper interval is 4 to 7 times.
  Here, for example, in the case of 120 mg toner input, the number of times of input between sheets is four, but when the number of sheets passed through the job is four or less, toner input cannot be completed between sheets, so the uninputted amount is , Input after the job. The same applies to a toner input amount of 150 to 210 mg.
[0047]
  The start current detection / toner input operation is performed with an appropriate number of sheets to be passed (the number of copies) in the same manner as described above. For example, when the operation is performed about every 500 sheets, the image carrier 1 can be efficiently processed without interruption. It becomes possible to remove the material filmed on the surface.
[0048]
  EmbodimentExamples of 4 and 12 are shown below.
  SaidEmbodimentIn the toner input operations 3 and 11, when the toner input between the transfer paper passes through the transfer belt unit 9 provided in the transfer means 4, the transfer state is controlled to be released. That is, transfer of the transfer paper by the transfer means is stopped and the transfer current does not flow (the transfer belt unit 9 is separated from the image carrier).
  In order to eliminate the time loss caused by the operation for canceling the transfer state, the transfer residual toner amount is increased by controlling the transfer current value (lowering the transfer current value) while maintaining the transfer state in the toner input operation, The toner input to the cleaning brush 5 is increased.
[0049]
  By controlling as described above, there is no need to release the transfer state between the transfer sheets, and the interval between the transfer sheets can be shortened, so that the productivity of the image forming apparatus is not lowered. .
  The start-up current detection and toner input operations are performed at an appropriate number of sheets to be passed (for example, about every 500 sheets), so that the operation is not interrupted and the filming is performed on the surface of the image carrier 1 without reducing productivity. The removed material can be removed.
[0050]
  EmbodimentEmbodiments 5 and 13 are shown below.
  SaidEmbodimentBy controlling the transfer current value (lowering the transfer current value) while maintaining the transfer states 4 and 12, useless time can be saved. However, there is a concern that an inconvenience that the image density is lowered by lowering the transfer current.
  For example, as shown in the relationship between the toner amount (M / A) on the image carrier and the image density in FIG. 5, when the transfer current value is 120 μA (current), the image density on the transfer paper is about 1.4. Transfer is performed at a specified density. In this case, the developing potential is controlled to about 500 V, and the toner amount (M / A) applied on the image carrier is about 0.6 mg / cm.²The transfer is performed on the transfer paper. However, the same conditions (developing potential: about 500 V, toner amount on image carrier (M / A): about 0.6 mg / cm²), The transfer efficiency is lowered when the transfer current is lowered to 50 μA, for example, and the image density on the transfer paper is reduced to about 1.3.
[0051]
  In order to eliminate such an inconvenience, the relationship between the developing potential and the toner amount on the image carrier (M / A) shown in FIG. 6 is used only when the transfer current value is lowered and the residual toner input amount is controlled and supplied. Based on this, a method for controlling the development potential to be high was applied.
  For example, when the development potential is 600 V in FIG. 6, the toner amount (M / A) on the image bearing member is about 0.8 mg / cm.²Thus, in the case of this toner amount, it can be seen from FIG. 5 that the image density on the transfer paper of 1.4 can be secured even if the transfer current is lowered to 50 μA. That is, even if the transfer current value is lowered as described above in order to increase the residual toner amount, the problem of decrease in image density on the transfer paper can be solved by setting the developing potential to about 600 V or more.
[0052]
  That is, the toner input operation is not performed between transfer paper passes, but the development potential is controlled (increased in potential) while the paper is passed, and the transfer current is decreased to increase residual toner. It is efficient because the filming substance can be removed.
  The start current detection / toner input operation is performed with an appropriate number of sheets to be passed (the number of copies) in the same manner as described above. For example, when the operation is performed about every 500 sheets, the image carrier 1 can be efficiently processed without interruption. It becomes possible to remove the material filmed on the surface.
[0053]
  EmbodimentEmbodiments 6 and 14 are shown below.
  On the other hand, when the filming substance is firmly fixed, fluctuations in the detection starting current value, that is, the reference value (FIG. 3) or the threshold value (FIG. 4) may be a condition that requires the input of residual toner. Conceivable. In such a case, toner input is performed every predetermined number of sheets, for example, every 500 copies, and the amount of toner consumption increases.
  Therefore, when the detection start-up current value changes continuously when the number of transfer sheets passes, and it is necessary to input residual toner, the cleaning brush is pressed against the image carrier in accordance with the number of times that the residual toner needs to be input. Control to increase the power. That is, a mechanism (cleaning brush pressurizing mechanism) that makes the pressure contact force of the cleaning brush against the image carrier variable is provided. For example, when a starting current threshold value or a reference value for performing toner input twice in succession is detected, 3 At the time of the input detection after the first time, while the pressure contact force of the cleaning brush to the image carrier is increased simultaneously with the toner input, the amount of residual toner input is controlled and supplied to remove the firmly fixed filming substance.
[0054]
  An example of a schematic configuration of a support mechanism capable of varying the pressure contact force of the cleaning brush to the image carrier is shown in the schematic diagram of FIG.
  In FIG. 7, one end of the pressure spring 44 is locked to the end of the swing arm 43, and when a starting current threshold value or a reference value for performing toner input at a preset number of consecutive times is detected, the pressure solenoid 45 is turned on. When the cleaning brush 42 is moved to a position where the pressure contact force further increases from the normal position, the surface of the image carrier 41 is rubbed with a larger rubbing force than during the normal cleaning operation. Try to remove more material faster than usual.
  Here, the normal position is a predetermined position adjusted so that the cleaning brush 42 is pressed against the surface of the image carrier 41 with a predetermined amount of biting in a normal cleaning operation. The operation is performed by moving the cleaning brush 42 in the direction of increasing the amount of biting into the surface of the image carrier 41 by 45.
[0055]
  EmbodimentEmbodiments 7 and 15 are shown below.
  If the rotation direction of the cleaning brush is fixed in the trailing direction as described above, the ability to polish the image carrier is lower than that in the counter direction, leading to a longer life of the image carrier, but the ability to remove the filming material is counter direction. Low compared to On the other hand, if the rotation direction of the cleaning brush is fixed in the counter direction, the polishing ability of the surface of the image carrier is superior to that of the trailing direction, and the filming substance removal ability is improved, but the surface of the image carrier itself is also polished. This will lead to reduced life.
  Therefore, the rotation direction of the motor for driving the cleaning brush can be switched to the trailing direction or the counter direction with respect to the moving direction of the image carrier, and the detection starting current value fluctuation when a predetermined number of transfer papers are fed is input to the residual toner. The filming substance is removed by controlling the rotation in the trailing direction when no toner is required, and rotating in the counter direction when the residual toner is required.
[0056]
  That is, the following control is performed. When the job starts, the cleaning brush starts rotating in the trailing direction with respect to the image carrier. If the reference value or threshold value that requires the residual toner input is applied to detect the starting current for every 500 sheets, the next starting current is detected. The cleaning brush is switched to rotation in the counter direction with respect to the image bearing member up to 500 sheets. Then, it is not necessary to perform toner input with subsequent startup current detection (residual toner input is not required). If the threshold value startup current threshold value is met, the cleaning brush is imaged up to 500 sheets with the next startup current detection. Switch to the trailing direction with respect to the bearing itself. By performing such an operation, the scraping amount of the image carrier can be set to an intermediate value between the trailing direction only and the counter direction only, and the filming substance can be effectively removed. Can do.
[0057]
  EmbodimentEmbodiments 8 and 16 are shown below.
  SaidEmbodimentIn the operations 7 and 15, when the rotation direction of the cleaning brush with respect to the image carrier is switched to the counter direction, the rotation number of the cleaning brush is simultaneously controlled by a motor capable of changing the rotation number. For example, as shown in Table 1 below, as shown in Table 1 below, the motor rotation number (the number of rotations of the cleaning brush) is set for the number of continuous detections of the starting current value that requires residual toner input, and control is performed based on this setting condition. Thus, the filming substance attached to the surface of the image carrier can be efficiently removed with less toner consumption. Table 1 is an example, and the present invention is not limited to this.
[0058]
[Table 1]

[0059]
  The conditions for switching the rotation direction to the counter direction are as described above.EmbodimentAs in 7 and 15, the starting current value of the motor driving the cleaning brush is detected every predetermined number of sheets (for example, 500 sheets), and a reference value (FIG. 3) or threshold ( 4), only when the cleaning brush is switched to counter rotation, the filming substance is controlled by controlling the number of rotations of the cleaning brush according to the number of continuous detections of the residual toner input required. Try to remove it.
  For example, when the motor rotation speed magnification is controlled as shown in Table 1, the relationship between the image carrier surface scraping amount with respect to the number of jobs and the consumed toner weight with respect to the number of jobs is as shown in FIGS. By controlling the rotation rate magnification,EmbodimentCompared to the operations of 7 and 15, the image carrier surface scraping amount is reduced, leading to a longer life of the image carrier, and the toner consumption weight is also reduced, so that the filming substance adhering to the surface of the image carrier can be efficiently removed. .
[0060]
  EmbodimentSeventeen embodiments are shown below.
  The embodimentIn 1 to 16, toner input is controlled to the minimum necessary, but the residual toner outside the input image area is consumed anyway, so the toner yield is lowered.
  Therefore, the toner consumption is reduced by providing toner recycling means in the cleaning means (having a cleaning brush and a cleaning blade) of the image forming apparatus. FIG. 10 is a partial schematic diagram of an image forming apparatus provided with toner recycling means.
[0061]
  In FIG. 10, in the image forming apparatus, the toner collected from the image carrier 20 by the cleaning brush 21, the cleaning blade 22, and the collection coil 23 attached to the cleaning unit 24 is supplied to the developing filter 26, the conveyance screw 27, and the agitation. There is provided a toner recycling means 33 having a transfer mechanism (for example, a screw conveyor) for transporting to a developing means 32 incorporating mechanisms such as a roller 28, a paddle roller 29, and sleeves 30 and 31. The toner recycling unit 33 may include a toner classification function.
  By such toner recycling means 33, the collected residual toner can be recycled and reused, so that wasteful consumption can be avoided and the decrease in toner yield can be suppressed, and the filming material on the mirror surface of the image carrier 20 can be prevented. Removal can be performed.
[0062]
【Example】
  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.In addition, Examples 1-3 and 8-10 are reference examples.
[0063]
  Example 1 (The embodimentExample according to 1 and 2)
  This embodiment relates to the amount of toner input using the image forming apparatus (apparatus modified from Ricoh's Imagio MF8570) having the means shown in FIG. 1 and having the configuration shown in the partial schematic diagram of FIG. An evaluation test was conducted.
  The image bearing member 20 shown in FIG. 10 used in this embodiment is a photosensitive member having a diameter of 100 mm that has an overcoated photosensitive surface layer and improved wear resistance. As the cleaning brush 21, those shown in Table 2 below were used.
[0064]
[Table 2]

[0065]
  As a result of the evaluation by the cleaning brush 21 having the specifications shown in Table 2 above, as a result of the start, that is, when the cleaning brush 21 is activated when the filming substance that causes image flow is not attached to the image carrier 20. The torque value was 0.408 kgf · cm (0.040 N · m). On the other hand, the static torque value when the filming substance is adhered by the transfer operation is 0.323 kgf · cm (0.032 N · m), which is 0.085 kgf · cm (0.008 N · m It was found that a change in m) occurred.
[0066]
  As a result of measuring the driving current value (starting current value) at the time of starting of the cleaning brush 21 with respect to the change of the static torque value, the relationship as shown in FIG. 11 was obtained. As is apparent from FIG. 11, the static torque value and the starting current value are in a proportional relationship. Therefore, the change in the static torque value can be converted into the starting current value, and the toner can be detected by detecting the starting current value. It was confirmed that input can be judged and controlled.
[0067]
  Further, from the relationship shown in FIG. 11, an average value 0.36 of the starting current value 0 · 38 when filming is not performed and the starting current value 0.34 when filming is obtained is set as a reference value. (Refer to FIG. 12) When the transfer amount of toner is controlled and supplied at the end of the job while detecting the start-up current value while the filming substance is adhered to every 500 sheets of transfer paper, image flow or the like occurs. High-quality images with a reduced rate could be obtained continuously.
  In the toner input control, when the detected starting current value is larger than the reference value, toner input is not performed. When the detected starting current value is smaller than the reference value, writing is performed with half the normal light amount. 300 mm, length 90 mm, toner amount about 0.5 mg / cm²The toner was input at the end of the job under the conditions of
[0068]
  Example 2 (The embodimentExample according to 3)
  Instead of the toner input after the end of the job, the toner is input between the continuous paper passes, and the toner input between the paper passes the transfer belt unit (corresponding to the transfer belt unit 9 in FIG. 1). In the same manner as in Example 1, except that the transfer belt unit is controlled to be separated from the image carrier (corresponding to the image carrier 1 in FIG. 1) when passing, the reference value (0.36A) is used. Copying was performed while detecting the starting current for every 500 sheets of transfer paper. As a result, the filming substance can be removed more efficiently, and a high-quality image without image flow was obtained.
[0069]
  Example 3 (The embodimentExample according to 4)
  In the second embodiment, when the toner input between the sheets passes through the transfer belt unit, the transfer belt unit is controlled to be “separated” from the image carrier (transfer state is released). Instead, the transfer belt unit is maintained in a transfer state “without being separated” from the image bearing member, and the transfer current value is decreased and the transfer residual toner amount is increased while continuously passing the paper. In the same manner as in Example 2, copying was executed while detecting the starting current for every 500 sheets of transfer paper. As a result, the filming substance can be efficiently removed without wasting time, and a high-quality image without image flow was obtained.
[0070]
  Example 4 (The embodimentExamples according to 5 and 13)
  As an operation condition in normal image formation, in the case where an image forming apparatus set with a developing potential of about 500 V and a transfer current value of 120 μA requires toner input control / supply, the developing potential is increased to 600 V and the transfer current is increased. The toner was controlled to be reduced to 50 μA and the residual toner was supplied while the paper was passing. The image density on the obtained transfer paper was about 1.4, and the transfer density did not decrease, and a good image was obtained as usual. In addition, the filming substance could be removed efficiently.
[0071]
  Example 5 (The embodimentExamples according to 6 and 14)
  When the filming substance is firmly fixed and difficult to remove (using an image area ratio of 6% chart), copying is performed and the cleaning brush pressurization mechanism is provided (present) and not provided (none). Each toner consumption was evaluated. FIG. 13 shows the relationship between the obtained number of jobs (number of sheets to be passed) and consumed toner weight.
  As shown in FIG. 13, the filming substance starts to adhere to the surface of the image carrier after about 100,000 jobs, and when there is no cleaning brush pressurizing mechanism, in addition to the amount of toner consumed in normal jobs after 100,000 sheets Further, toner for replenishment is consumed.
  When the cleaning pressurizing mechanism is provided, the number of toner replenishment times is reduced as compared to the case without the cleaning pressurizing mechanism, the toner replenishment amount is reduced, and the filming substance is also removed. It was found that the toner consumption was reduced by about 900 g for 300,000 jobs. That is, the filming substance could be removed more than usual with the minimum necessary toner consumption.
[0072]
  Example 6 (The embodimentExamples according to 7 and 15)
  The case where the rotation direction of the cleaning brush in Embodiments 7 and 15 can be switched was evaluated.
  In FIG. 14, when the rotation direction of the cleaning brush is fixed in the trailing direction, when it is fixed in the counter direction, and when the detection starting current value fluctuation does not require the input of the residual toner as described above, and when the input is required. The amount of scraping of the surface of the image carrier with respect to the number of jobs (in the present invention) when switching between the trailing direction and the counter direction is controlled. By performing the operation of the present invention, the scraping amount of the image bearing member becomes almost an intermediate value between the trailing direction and the counter direction. By the control of the present invention, the filming substance adhering to the surface of the image carrier can be removed efficiently. In addition, the amount of abrasion on the surface of the image carrier is reduced compared to when the cleaning brush is rotated in the counter direction with respect to the image carrier, leading to a longer life of the image carrier.
[0073]
  Example 7 (The embodimentExamples according to 8 and 16)
  As a result of controlling the motor speed magnification as shown in Table 1 in the embodiment, the image carrier surface scraping amount was reduced by 0.2 μm for 300,000 jobs and the toner consumption weight was reduced by about 950 g. According to the present invention, the filming substance adhering to the surface of the image carrier is efficiently removed with less toner consumption, andEmbodimentThe amount of scraping on the surface of the image carrier was reduced as compared with the operations of Nos. 7 and 15, leading to a longer life of the image carrier.
[0074]
  Example 8 (The embodimentExamples according to 9 and 10)
  FIG. 15 shows the result of examining the change in the starting current value corresponding to the case where the image flow of the transferred image does not occur during the time of copying from 0 to 300K sheets and the case where image flow occurs.
  From the test results, the toner input amount was set by dividing the number of sheets to be passed (number of copies) and the starting current value into threshold categories shown in Table 3 below. Based on this set value, the residual toner input amount to the cleaning brush is set in advance so that the toner consumption efficiency becomes small as a result of executing copying while checking the starting current for every 500 sheets of transfer paper. Therefore, the filming substance can be efficiently removed without consuming more toner than necessary, and a high-quality image without image flow was obtained. The toner input is about 0.5 mg / cm with half the normal light quantity.²Toner input was performed at the end of the job.
[0075]
[Table 3]

[0076]
  Example 9 (The embodiment11)
  Instead of the toner input after the end of the job, the toner is input between the continuous paper passes, and the toner input between the paper passes the transfer belt unit (corresponding to the transfer belt unit 9 in FIG. 1). In the same manner as in Example 4, except that the transfer belt unit is controlled to be separated from the image carrier (corresponding to the image carrier 1 in FIG. 1) when passing, the reference value (0.36A) is used. Copying was performed while detecting the starting current for every 500 sheets of transfer paper. As a result, the filming substance can be removed more efficiently without consuming more toner than necessary, and a high-quality image without image blur was obtained.
[0077]
  Example 10The embodiment12)
  In the ninth embodiment, when the toner input during the sheet passing passes through the transfer belt unit, the transfer belt unit is controlled to “leave” from the image carrier (transfer state is released). Instead, the transfer belt unit is maintained in a transfer state “without being separated” from the image bearing member, and the transfer current value is decreased and the transfer residual toner amount is increased while continuously passing the paper. In the same manner as in Example 9, copying was performed while detecting the starting current for every 500 sheets of transfer paper. As a result, the filming substance can be removed more efficiently without consuming more toner than necessary, and without wasting time, and a high-quality image without image flow was obtained.
[0078]
  Example 11 (The embodimentExample according to 17)
  The embodimentIn Nos. 1 to 16, since the amount of toner input outside the image area is increased when removing the filming substance, the toner consumption is basically accompanied. Therefore, when the toner recycling means 33 is operated, the toner consumption is reduced as compared with the case where the toner recycling means 33 is not operated, and the filming substance can be removed without causing a decrease in toner yield.
[0079]
【The invention's effect】
  According to the image forming apparatus of the first aspect, by detecting the starting current value that changes in conjunction with the static torque value of the cleaning brush drive motor and performing control to increase the residual toner input amount as necessary, Since the filming substance adhering to the body is removed, the occurrence of image flow, toner image fading, or background smudge is eliminated, and a stable image free from defects can be obtained.In addition, the transfer operation required for releasing the transfer state is simplified, and the filming material adhering to the image carrier is removed by the minimum necessary operation without wasting time. A high-quality image that maintains the image density without causing defects can be stably obtained.
[0080]
  According to the image forming apparatus of claim 2,By removing more filming material on the surface of the image carrier faster than usual, high-quality images can be stably obtained without causing problems such as image flow even with continuous paper feeding.
[0081]
  According to the image forming apparatus of claim 3,Since the filming material can be efficiently removed with the minimum necessary residual toner input, the surface of the image bearing member can be reduced, and even if continuous paper is passed, there is no problem such as image flow. Images can be obtained stably.
[0082]
  According to the image forming apparatus of claim 4,Since the polishing of the surface of the image carrier can be reduced and the filming substance can be efficiently removed, high-quality images can be stably obtained without causing problems such as image flow even with continuous paper feeding.
[0083]
  According to the image forming apparatus of claim 5,By providing the residual toner recycling means in the image forming apparatus, the amount of toner consumption can be reduced, the filming substance can be removed without causing a reduction in toner yield, and waste can be eliminated.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a main configuration example for explaining an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a conceptual diagram schematically showing a relationship between a starting current value and a static torque value of a cleaning brush drive motor applied to toner input control of the present invention in the embodiment.
FIG. 3 is a conceptual diagram schematically illustrating a relationship in which toner input is controlled by setting a reference value from a starting current value when filming is performed and when filming is not performed in the embodiment.
FIG. 4 is a conceptual diagram illustrating an example of setting a toner input amount by thresholding an accumulated sheet passing number and a starting current value with occurrence and non-occurrence of image flow as parameters in the embodiment.
FIG. 5 is a diagram showing the relationship between the toner amount on the image carrier and the image density on the transfer paper when controlling the transfer current value and the development potential in the embodiment.
FIG. 6 is a diagram illustrating a relationship between a development potential and a toner amount on an image carrier when controlling a transfer current value and a development potential in the embodiment.
FIG. 7 is a schematic diagram showing a schematic configuration for explaining a cleaning brush pressurizing mechanism for controlling the pressing force of the cleaning brush against the image carrier in the embodiment.
FIG. 8 is a diagram showing the relationship between the number of jobs and the amount of image carrier scraping when controlling the rotation direction and the number of rotations of the cleaning brush in the embodiment.
FIG. 9 is a diagram showing the relationship between the number of jobs and the toner consumption weight when controlling the rotation direction and rotation speed of the cleaning brush in the embodiment.
FIG. 10 is a partial schematic diagram of an image forming apparatus (modified from Ricoh's Imagio MF8570) provided with toner recycling means in the embodiment and examples.
FIG. 11 is a diagram showing a relationship between a starting current value and a static torque value in an example of the present invention.
FIG. 12 is a diagram illustrating a relationship set from a starting current value when a reference value for toner input control in the embodiment of the present invention is not filmed and when it is not filmed.
FIG. 13 is a diagram illustrating a relationship between the number of jobs and the toner consumption weight when the cleaning brush is pressed and not pressed according to the embodiment of the present invention.
FIG. 14 is a diagram showing the relationship between the number of jobs and the amount of image carrier scraping when the rotation direction of the cleaning brush is controlled in the embodiment of the present invention.
FIG. 15 is a diagram illustrating a relationship between a starting current value at the time of occurrence and non-occurrence of an image flow and a cumulative number of sheets passed in an embodiment of the present invention.
[Explanation of symbols]
  1 Image carrier
  2 Charging means
  3 Development means
  4 Transfer means
  5 Cleaning brush
  6 Cleaning blade
  7 Cleaning means
  8 Static elimination means
  9 Transfer belt unit
  20 Image carrier
  21 Cleaning brush
  22 Cleaning blade
  23 Recovery coil
  24 Cleaning means
  26 Development filter
  27 Conveying screw
  28 Stirrer roller
  29 Paddle Roller
  30 sleeves
  31 sleeve
  32 Developing means
  33 Toner recycling means
  41 Image carrier
  42 Cleaning brush
  43 Swing arm
  44 Pressure spring
  45 Pressurized solenoid

Claims (5)

An image carrier comprising a rotating photoconductor, a charging means for charging the image carrier, and exposure for exposing the charged image carrier to form an electrostatic latent image on the image carrier And supplying toner to the image carrier to develop a toner image corresponding to a development potential which is a difference between the charging potential of the charging means on the image carrier and the potential of the electrostatic latent image. Developing means for transferring, transferring means for conveying the transfer paper and applying a charge to the transfer paper to transfer the toner image on the image carrier, and remaining on the image carrier after transfer to the transfer paper In the image forming apparatus having, on the image carrier in this order in the rotation direction of the image carrier, cleaning means for removing at least a residual toner as a toner by a cleaning brush driven by a drive motor,
When a predetermined number of sheets of transfer paper are passed, the starting current value of the drive motor is determined by the starting current value when the filming material is attached to the image carrier and the starting current value when the filming material is not attached. If greater than the reference value is a value between the previous SL without the residual increase residual toner input quantity is the amount of the toner control supplied to the cleaning unit, the starting current value of the drive motor, the reference value If smaller than the performs control to increase the pre-Symbol residual toner input variables, a function of removing filming material formed on the image bearing member,
The control for increasing the residual toner input amount is a transfer current related to charge application to the transfer paper while maintaining the transfer state in which the transfer means transfers the toner image on the image carrier to the transfer paper. An image forming apparatus, wherein the image forming apparatus controls the developing potential so as to prevent the image density of the transfer paper from being lowered while performing control to lower the value.   The pressure contact force of the cleaning brush to the image carrier is variable, and the starting current value of the drive motor is smaller than the reference value for every predetermined number of sheets of transfer paper to supply residual toner to the cleaning means. When necessary cases are continuously generated, the pressure contact force is controlled to increase according to the number of consecutive times of performing the control to increase the residual toner input amount, and the control to increase the residual toner input amount is performed to firmly fix. The image forming apparatus according to claim 1, wherein the filming material is removed.   The rotation direction of the cleaning brush driven by the drive motor can be switched to the trailing direction or the counter direction with respect to the moving direction of the image carrier, and the starting current value of the drive motor and the reference value when a predetermined number of transfer sheets are used According to the comparison result, the rotation is controlled in the trailing direction when supply of the residual toner to the cleaning unit is not required, and the counter direction is rotated when supply of the residual toner to the cleaning unit is required. 2. The image forming apparatus according to claim 1, wherein the mingling material is removed.   Only when the cleaning brush is switched to rotation in the counter direction, the cleaning brush rotation speed is increased in accordance with the number of consecutive times of performing the control to increase the residual toner input amount, and the filming substance is removed. The image forming apparatus according to claim 3. The image forming apparatus according to any one of claims 1 to 4, characterized in that it comprises recycling means for recycling and recovering the residual toner.

Images