JP2000221819A - Fixing device and image forming device - Google Patents
Fixing device and image forming deviceInfo
- Publication number
- JP2000221819A JP2000221819A JP11026199A JP2619999A JP2000221819A JP 2000221819 A JP2000221819 A JP 2000221819A JP 11026199 A JP11026199 A JP 11026199A JP 2619999 A JP2619999 A JP 2619999A JP 2000221819 A JP2000221819 A JP 2000221819A
- Authority
- JP
- Japan
- Prior art keywords
- recording material
- bias
- fixing
- electrode
- image
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Fixing For Electrophotography (AREA)
- Control Or Security For Electrophotography (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、定着装置及び画像
形成装置に関し、例えば複写機、レーザープリンタ、フ
ァキシミリ等、電子写真プロセスを用いる画像形成装置
の定着装置に好適なものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device and an image forming apparatus, and is suitable for a fixing device of an image forming apparatus using an electrophotographic process, such as a copying machine, a laser printer, and a facsimile.
【０００２】[0002]
【従来の技術】上記周知の画像形成装置では、例えば感
光体面上を光走査して該面上の電位を変化させ、該電位
の変化による像、即ち静電潜像を形成し、この潜像の電
位に応じてトナーを付与し、トナー像を形成する。次い
で該感光体のトナー像形成部分と対向するように配置し
た転写部材と、該感光体との間（転写部）に記録材を導
入し、該転写部材側からトナーと異極性の転写バイアス
を印加してトナーを引き寄せ、該記録材上にトナー像を
静電的に担持させる。そして、該トナー像を担持した記
録材を定着装置に導入し、加熱及び加圧して該トナー像
を記録材に定着させている。2. Description of the Related Art In the above-mentioned known image forming apparatus, for example, an optical scanning is performed on a photoreceptor surface to change a potential on the surface, and an image due to the change in the potential, that is, an electrostatic latent image is formed. And a toner image is formed in accordance with the potential of the toner. Next, a recording material is introduced between a transfer member (transfer portion) arranged to face the toner image forming portion of the photoconductor and the photoconductor, and a transfer bias having a polarity different from that of the toner is applied from the transfer member side. The toner is attracted by the application, and the toner image is electrostatically carried on the recording material. Then, the recording material carrying the toner image is introduced into a fixing device, and the toner image is fixed on the recording material by applying heat and pressure.
【０００３】このような画像形成装置では、高温高湿環
境など、記録材の含水分量が多い状態であると、転写部
で記録材の裏面に供給される転写電荷が記録材沿面を伝
達してリークしやすく、記録材上に静電的に転写形成さ
れたトナー像の保持力を失いやすい。また含水分量が多
いと、定着ニップ部で発生する蒸気量が増え、特に横線
画像で尾びきと呼ばれる蒸気の圧力によるトナー飛散が
発生することがあった。In such an image forming apparatus, when the recording material has a high moisture content, such as in a high-temperature, high-humidity environment, the transfer charge supplied to the back surface of the recording material at the transfer unit is transmitted along the surface of the recording material. The toner easily leaks and easily loses the holding power of the toner image electrostatically transferred and formed on the recording material. Further, when the water content is large, the amount of steam generated in the fixing nip increases, and in particular, the toner may be scattered due to the pressure of the steam, which is called tailing in the horizontal line image.
【０００４】また、記録材裏面の転写電荷によるトナー
像の保持力が弱まるため、記録材に定着されずに定着フ
ィルムまたは定着ローラにトナーが付着するオフセット
現象が発生しやすく、これにより定着フィルムまたは定
着ローラの１回転後に付着していたトナーが記録材に定
着される画像不良が発生しやすかった。Further, since the holding power of the toner image due to the transfer charge on the back surface of the recording material is weakened, an offset phenomenon in which the toner adheres to the fixing film or the fixing roller without being fixed to the recording material easily occurs. An image defect in which toner adhered after one rotation of the fixing roller was fixed on the recording material was likely to occur.
【０００５】また、該オフセット現象により定着フィル
ムまたは定着ローラに付着したトナーが、この定着フィ
ルムまたは定着ローラに対向して圧接される加圧ローラ
に転移し、加圧ローラ汚れを発生させる要因となってい
た。Further, the toner adhered to the fixing film or the fixing roller due to the offset phenomenon is transferred to the pressing roller which is pressed against the fixing film or the fixing roller, thereby causing contamination of the pressing roller. I was
【０００６】そこで本発明者らは、以下のような定着装
置を提案した。Accordingly, the present inventors have proposed the following fixing device.
【０００７】すなわち、定着フィルムまたは定着ローラ
にトナーの帯電極性と同極性のバイアスを印加し、記録
材に接する接地電極を設ける。もしくは排紙ガイドまた
は定着入り口ガイドにバイアスを印加して定着フィルム
または定着ローラをアースする。これらの構成により定
着フィルムまたは定着ローラから記録材を介する電流経
路ができ、フィルムまたは定着ローラと記録材との間に
電圧降下が生じ、発生する電界がトナー保持力として働
く。トナー保持力は定着ニップで発生する蒸気の圧力、
定着フィルムとトナーとの間に発生するファンデルワー
ルス力、鏡像力などに打ち勝ってトナー像の定着効率を
向上させ、尾びきと呼ばれるトナー飛散、オフセットと
呼ばれる画像不良、加圧ローラ汚れを防止する。That is, a bias having the same polarity as the charged polarity of the toner is applied to the fixing film or the fixing roller, and a ground electrode is provided in contact with the recording material. Alternatively, a bias is applied to the paper ejection guide or the fixing entrance guide to ground the fixing film or the fixing roller. With these configurations, a current path is formed from the fixing film or the fixing roller through the recording material, a voltage drop occurs between the film or the fixing roller and the recording material, and the generated electric field acts as a toner holding force. The toner holding power is the pressure of steam generated in the fixing nip,
It overcomes van der Waals force and mirror image force generated between the fixing film and toner to improve the fixing efficiency of the toner image, and prevents toner scattering called tail tail, image defect called offset, and pressure roller contamination. .
【０００８】[0008]
【発明が解決しようとする課題】しかしながら上記構成
の定着装置では、上記バイアス印加手段から印加される
バイアスが、定電流でなされる場合、定着フィルムまた
は定着ローラや記録材の電気抵抗が高いとき、バイアス
印加手段に対する電圧負荷が大きくなる。However, in the fixing device having the above structure, when the bias applied from the bias applying means is a constant current, when the electric resistance of the fixing film or the fixing roller or the recording material is high, The voltage load on the bias applying means increases.
【０００９】また、印加されるバイアスが大きいと、定
着フィルムまたは定着ローラ表面の電位も大きくなる。
印加バイアスはトナーと同極性なので、前記表面電位が
適正範囲であれば、上記定着装置の設計意図通りとなる
が、前記表面電位が必要以上に大きいと、定着前のトナ
ーが、前記表面電位と同極性のため反発し、画像が乱れ
ることがある。When the applied bias is large, the potential on the surface of the fixing film or the fixing roller also increases.
Since the applied bias has the same polarity as that of the toner, if the surface potential is in an appropriate range, the fixing device is designed as intended.However, if the surface potential is larger than necessary, the toner before fixing has the same surface potential as the toner. Repulsion due to the same polarity may disturb the image.
【００１０】また、上記バイアス印加手段から印加され
るバイアスが、定電圧でなされる場合、定着フィルムま
たは定着ローラや記録材の電気抵抗が高いと、上記定着
器に通電される電流値が小さくなり、尾引きやオフセッ
トに対する効果が減少してしまう。Further, when the bias applied from the bias applying means is a constant voltage, if the electric resistance of the fixing film or the fixing roller or the recording material is high, the value of the current supplied to the fixing device becomes small. The effect on tailing and offset is reduced.
【００１１】そこで本発明は以上の点を鑑み、記録材を
介して流れる電流に応じてバイアスを印加することで、
環境変化によらずに最適なバイアスを印加することがで
き、トナー飛散や画像不良等を常に良好に防止すること
が可能な定着装置及び画像形成装置の提供を目的とす
る。In view of the above, the present invention applies a bias in accordance with a current flowing through a recording material,
An object of the present invention is to provide a fixing device and an image forming apparatus that can apply an optimal bias regardless of environmental changes and can always prevent toner scattering and image defects.
【００１２】[0012]
【課題を解決するための手段】〔１〕：互いに圧接して
定着ニップを形成する加熱部材と加圧部材を有し、前記
定着ニップで記録材を挟持搬送して記録材上のトナー像
を加熱・加圧して定着させる定着装置において、前記加
熱部材または前記加圧部材の少なくとも一方にバイアス
を印加するバイアス印加手段と、前記記録材に当接する
電極と、前記電極に流れる電流を検知する検知手段と、
を有し、前記記録材が前記定着ニップと前記電極との双
方に接触する位置に達したときの前記記録材を介して前
記電極に流れる電流を前記検知手段で検知し、この検知
結果に基づいて前記バイアス手段から前記加熱部材に印
加されるバイアスを変更することを特徴とする定着装
置。Means for Solving the Problems [1]: A heating member and a pressing member which press against each other to form a fixing nip are provided, and the recording material is nipped and conveyed by the fixing nip to form a toner image on the recording material. In a fixing device for fixing by heating and pressing, a bias applying means for applying a bias to at least one of the heating member and the pressing member, an electrode in contact with the recording material, and a detection for detecting a current flowing through the electrode Means,
A current flowing through the electrode through the recording material when the recording material reaches a position where the recording material comes into contact with both the fixing nip and the electrode. Wherein the bias applied from the bias unit to the heating member is changed.
【００１３】〔２〕：前記電極が接地されていることを
特徴とする〔１〕記載の定着装置。[2] The fixing device according to [1], wherein the electrode is grounded.
【００１４】〔３〕：互いに圧接して定着ニップを形成
する加熱部材と加圧部材を有し、前記定着ニップで記録
材を挟持搬送して記録材上のトナー像を加熱・加圧して
定着させる定着装置において、前記記録材に当接する電
極と、前記電極にバイアスを印加するバイアス印加手段
と、前記加熱部材に流れる電流を検知する検知手段と、
を有し、前記記録材が前記加熱部材と前記電極との双方
に接触したときの記録材を介して該電極から該加熱部材
にかけて流れる電流を前記検知手段で検知し、この検知
結果に基づいて前記バイアス手段から前記電極に印加さ
れるバイアスを変更することを特徴とする定着装置。[3]: A heating member and a pressing member which press against each other to form a fixing nip are provided. In the fixing device, an electrode that contacts the recording material, a bias applying unit that applies a bias to the electrode, and a detecting unit that detects a current flowing through the heating member,
Having the detecting member detect a current flowing from the electrode to the heating member via the recording material when the recording material comes into contact with both the heating member and the electrode by the detection means, and based on the detection result, A fixing device, wherein a bias applied from the bias unit to the electrode is changed.
【００１５】〔４〕：前記加熱部材が接地されているこ
とを特徴とする〔３〕記載の定着装置。[4] The fixing device according to [3], wherein the heating member is grounded.
【００１６】〔５〕：互いに圧接して定着ニップを形成
する加熱部材と加圧部材を有し、前記定着ニップで記録
材を挟持搬送して記録材上のトナー像を加熱・加圧して
定着させる定着装置において、前記加熱部材または前記
加圧部材の一方にバイアスを印加するバイアス印加手段
と、前記加熱部材または前記加圧部材のバイアスが印加
されていない方に流れる電流を検知する検知手段と、を
有し、前記記録材が前記定着ニップに導入されて前記加
熱部材と前記加圧部材の双方と接触したときの前記記録
材を介して前記加熱部材と前記加圧部材との間に流れる
電流を前記検知手段で検知し、この検知結果に基づいて
前記バイアス手段から前記加熱部材または前記加圧部材
に印加されるバイアスを変更することを特徴とする定着
装置。[5]: A heating member and a pressure member which press against each other to form a fixing nip are provided. The recording material is nipped and conveyed by the fixing nip, and the toner image on the recording material is heated and pressed to fix the toner image. A fixing unit configured to apply a bias to one of the heating member and the pressing member; and a detection unit configured to detect a current flowing to a side of the heating member or the pressing member to which no bias is applied. Wherein the recording material flows between the heating member and the pressing member via the recording material when the recording material is introduced into the fixing nip and comes into contact with both the heating member and the pressing member. A fixing device, wherein a current applied to the heating member or the pressing member is changed from the biasing unit based on the detection result.
【００１７】〔６〕：前記加熱部材が、ヒータと、該ヒ
ータを内包する回転部材からなることを特徴とする
〔１〕乃至〔５〕の何れか１項に記載の定着装置。[6] The fixing device according to any one of [1] to [5], wherein the heating member comprises a heater and a rotating member including the heater.
【００１８】〔７〕：前記電流を検知したときの記録材
を定着ニップで挟持搬送している途中又は前記電流を検
知した記録材の次の記録材を定着ニップに導入するとき
に前記バイアスの変更を行うことを特徴とする〔１〕乃
至〔６〕の何れか１項に記載の像加熱装置。[7]: When the recording material at the time when the current is detected is nipped and conveyed by the fixing nip, or when the recording material next to the recording material at which the current is detected is introduced into the fixing nip, the bias voltage is applied. The image heating apparatus according to any one of [1] to [6], wherein the change is performed.
【００１９】〔８〕：記録材上にトナー像を形成する像
形成手段と、該トナー像を加熱して記録材上に定着させ
る像定着手段とを有する画像形成装置において、該像定
着手段として〔１〕乃至〔７〕の何れか１項に記載の像
加熱装置を備えたことを特徴とする画像形成装置。[8] In an image forming apparatus having an image forming means for forming a toner image on a recording material and an image fixing means for heating the toner image and fixing the toner image on the recording material, An image forming apparatus comprising the image heating device according to any one of [1] to [7].
【００２０】〈作 用〉定着装置及び画像形成装置を以
上のような構成とすることにより、環境の変化によって
記録材を介して流れる電流が異なっても適正なバイアス
印加を行うことができ、常に設計意図通りにトナー飛散
や画像不良等を防止することができる。<Operation> By configuring the fixing device and the image forming apparatus as described above, an appropriate bias can be applied even if the current flowing through the recording material varies due to environmental changes. It is possible to prevent toner scattering, image defects, and the like as designed.
【００２１】[0021]
【発明の実施の形態】〈第一の実施形態〉図１に本発明
の定着装置としての実施形態の１例を示した。同図中、
１０２はヒータであり、セラミック基板上に導電ペース
トが印刷されている。導電ペースト部は不図示の電源に
より給電されて発熱し、ヒータが所望の温度になるよう
に制御されている。１０３は定着フィルムであり、３層
構造になっている。もっとも内側の層はベース層であ
り、定着フィルム１０３のねじれ強度、平滑性などの機
械的特性を担う層で、ポリイミドなどの樹脂でできてい
る。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> FIG. 1 shows an example of an embodiment as a fixing device of the present invention. In the figure,
Reference numeral 102 denotes a heater on which a conductive paste is printed on a ceramic substrate. The conductive paste portion is supplied with power from a power source (not shown) to generate heat, and the heater is controlled to a desired temperature. A fixing film 103 has a three-layer structure. The innermost layer is a base layer, which is responsible for mechanical properties such as torsional strength and smoothness of the fixing film 103, and is made of a resin such as polyimide.
【００２２】次の層は導電プライマ層であり、カーボン
ブラックなどの導電性粒子が分散された導電層で、第三
層目とベース層の接合を行う接着剤の役目も担ってい
る。最も外側の層がトップ層であり、１×１０8〜１×
１０13Ωｃｍ程度の比較的高抵抗で離型性の良いフッ素
樹脂が分散された厚さ１０μｍ程度のコート層である。The next layer is a conductive primer layer, in which conductive particles such as carbon black are dispersed, and also serves as an adhesive for bonding the third layer and the base layer. The outermost layer is the top layer, and 1 × 10 8 to 1 ×
It is a coating layer having a thickness of about 10 μm in which a fluororesin having a relatively high resistance of about 10 13 Ωcm and good releasability is dispersed.
【００２３】１０１はヒータホルダであり、ヒータ１０
２の支持部材であり、かつ定着フィルム１０３の円滑な
回転を促す案内部材としての役割も持つ。これらのヒー
タ１０２やヒータホルダー１０１、定着フィルム１０３
は、本例の加熱部材を構成している。Reference numeral 101 denotes a heater holder,
2 and also serves as a guide member for promoting smooth rotation of the fixing film 103. These heater 102, heater holder 101, fixing film 103
Constitutes the heating member of this example.
【００２４】１０４は加圧ローラであり、アルミ、鋳鉄
などで作られる芯金をシリコンゴムなど耐熱性がある絶
縁の弾性体で覆っている。加圧ローラ１０４の表層はト
ナーとの離型性があるフッ素樹脂などがコートされてい
る。A pressure roller 104 covers a metal core made of aluminum, cast iron, or the like with a heat-resistant insulating elastic material such as silicon rubber. The surface layer of the pressure roller 104 is coated with a fluororesin or the like having releasability from the toner.
【００２５】１０５は接地電極であり、アルミ基板１５
ａに導電性の繊維１５ｂを植毛処理してあり、該導電性
繊維１５ｂの先端が記録材Ｐと摺擦するよう配置され、
アルミ基板１５ａが１０ｋΩの抵抗１０７を介し接地さ
れている。Reference numeral 105 denotes a ground electrode, which is an aluminum substrate 15
a, a conductive fiber 15b is implanted in the hair, and the leading end of the conductive fiber 15b is arranged to rub against the recording material P;
The aluminum substrate 15a is grounded via a 10 kΩ resistor 107.
【００２６】定着フィルム１０３はバイアス印加手段と
しての高圧電源１０９によりトナーの帯電電荷と同極性
に帯電されている。本例においてトナーＴは負の帯電極
性を示すことから、定着フィルム１０３に印加される電
圧も負である。The fixing film 103 is charged to the same polarity as the charged charge of the toner by a high voltage power supply 109 as a bias applying means. In this example, since the toner T has a negative charging polarity, the voltage applied to the fixing film 103 is also negative.
【００２７】定着フィルム１０３に印加されたバイアス
により電流は、該フィルム１０３から記録材Ｐを伝わり
接地電極１０５を介してアースに流れる。この電流の電
界によってトナーＴに記録材Ｐへの拘束力が生じ、尾引
きやオフセットなどの画像不良を防止する。A current is transmitted from the film 103 to the recording material P by the bias applied to the fixing film 103, and flows to the ground via the ground electrode 105. The electric field of the current causes the toner T to have a binding force on the recording material P, thereby preventing image defects such as tailing and offset.
【００２８】１１０は該記録材Ｐを介して接地電極１０
５に流れる電流を抵抗１０７にかかる電圧値として検知
する検知手段である。Reference numeral 110 denotes a ground electrode 10 via the recording material P.
5 is a detecting means for detecting the current flowing through the resistor 5 as a voltage applied to the resistor 107.
【００２９】ここで、本例では定着フィルム１０３に印
加されるバイアスが、環境や記録材Ｐの変化によらず最
適になるよう制御される。すなわち記録材Ｐが搬送さ
れ、センサー１０８によって監視される記録材先端が接
地電極１０５を通過し、定着ニップＮに到達して、記録
材が定着ニップＮと接地電極１０５との双方に接したと
き、高圧電源１０９から１０μＡの定電流で印加され
る。この電流値は、２３℃／６０ＲＨ％の環境下におい
て、定着フィルムトップ層抵抗中心値及び記録材標準抵
抗値（標準的な記録材の抵抗値）に基づいて求めた尾引
き・オフセット防止のための適正電流値である。Here, in this embodiment, the bias applied to the fixing film 103 is controlled so as to be optimal regardless of the environment and the change of the recording material P. That is, when the recording material P is conveyed and the leading edge of the recording material monitored by the sensor 108 passes through the ground electrode 105 and reaches the fixing nip N, and the recording material contacts both the fixing nip N and the ground electrode 105. , From the high voltage power supply 109 at a constant current of 10 μA. This current value is for preventing tailing and offset obtained based on the center value of the resistance of the fixing film top layer and the standard resistance value of the recording material (the standard recording material resistance value) in an environment of 23 ° C./60 RH%. Is an appropriate current value.
【００３０】そして接地電極１０５に流れる漏れ電流
が、１０ｋΩの抵抗１０７にかかる電圧値Ｖ０として検
知手段１１０に検知されて不図示のＣＰＵにモニターさ
れ、その電圧値Ｖ０から最適なバイアス値Ｖｔを算出
し、記録材Ｐのページ内途中から、高圧電源１０９によ
り定電圧でバイアスＶｔが印加されるように制御する。The leakage current flowing through the ground electrode 105 is detected by the detection means 110 as a voltage value V0 applied to the 10 kΩ resistor 107 and monitored by a CPU (not shown), and an optimum bias value Vt is calculated from the voltage value V0. Then, control is performed so that the bias Vt is applied at a constant voltage by the high-voltage power supply 109 from the middle of the page of the recording material P.
【００３１】本実施例では、Ｖｔ値を下記の式から算出
するように制御した。In this embodiment, control is performed so that the Vt value is calculated from the following equation.
【００３２】 Ｖｔ ＝ １２０ ＋ ０．８Ｖ０ （Ｖ）・・・・（１） この式は、図５に示すようなグラフから求められる。す
なわち、定着フィルムトップ層の工程上発生する抵抗上
下限品、紙種による抵抗上下限品及びそれらの組み合わ
せを各環境（１０℃／１５ＲＨ％、２３℃／６０ＲＨ
％、３２℃／８０ＲＨ％）での電圧特性と画像特性を調
べる。外部バイアス入力により、各環境・各組み合わせ
で、１０μＡ通電したときの電圧値Ｖ０と、定着フィル
ム１０３にバイアスＶｉｎを印加するときの画像不良発
生領域から、バイアス適正領域を求め、その範囲を通る
式とした。式（１）は定着装置の構成によって適宜定め
られる。Vt = 120 + 0.8V0 (V) (1) This equation is obtained from a graph as shown in FIG. That is, the upper and lower resistance products generated in the process of the fixing film top layer, the upper and lower resistance products depending on the paper type, and the combination thereof are used in each environment (10 ° C./15 RH%, 23 ° C./60 RH
%, 32 ° C./80 RH%). By an external bias input, an appropriate bias area is obtained from a voltage value V0 when a current of 10 μA is applied and an image defect generation area when a bias Vin is applied to the fixing film 103 in each environment and each combination. And Equation (1) is appropriately determined depending on the configuration of the fixing device.
【００３３】このような制御により、定着フィルムトッ
プ層の抵抗値の製造上のバラ付きや紙種による記録材Ｐ
の抵抗値変化、また環境によるフィルムトップ層や記録
材Ｐの抵抗値変化などがあっても、定着フィルム１０３
に印加するバイアス値を常に最適な値に設定する事がで
き、該条件（抵抗値変化）に影響されることなく尾引き
・オフセットの発生を防止できる。さらに高圧電源に対
する負荷が大きくなることを防ぐことができる。By such control, the recording material P varies depending on the manufacturing variation of the resistance value of the fixing film top layer and the paper type.
Of the fixing film 103 even if the resistance of the film top layer or the recording material P changes due to the environment.
Can always be set to the optimum value, and tailing and offset can be prevented from being generated without being affected by the condition (resistance change). Further, it is possible to prevent the load on the high-voltage power supply from increasing.
【００３４】また１ページ目にＶ０を印加（１０μＡで
定電流制御）し、２ページ以降バイアスＶｔを印加する
ように制御しても構わない。Alternatively, V0 may be applied to the first page (constant current control at 10 μA), and control may be performed so as to apply the bias Vt from the second page.
【００３５】また、本例は、記録材上のトナーＴの拘束
手段としてのバイアスを制御することを目的とするの
で、バイアス通電経路の構成にとらわれない。従って図
２のように、電極１０５を介して記録材裏面にバイアス
を印加し、定着フィルム１０３を接地する構成でも同様
な効果がある。この場合バイアスの極性はトナーと逆極
性とする。また、定着入口ガイド４１にバイアスを印加
しても良い。Further, since the purpose of this embodiment is to control the bias as a means for restraining the toner T on the recording material, the configuration of the bias energizing path is not limited. Accordingly, a similar effect can be obtained by applying a bias to the back surface of the recording material via the electrode 105 and grounding the fixing film 103 as shown in FIG. In this case, the polarity of the bias is opposite to that of the toner. Further, a bias may be applied to the fixing entrance guide 41.
【００３６】なお、定着装置は、本例のようなフィルム
定着装置に限定されるものでなく、熱ローラ方式の定着
装置においても同様な効果が得られる。Note that the fixing device is not limited to the film fixing device as in the present embodiment, and a similar effect can be obtained in a fixing device of a heat roller type.
【００３７】〈第二の実施形態〉先に説明した形態で
は、定着装置にバイアスを印加するに当たり、定電流の
立ち上がりからＶｔが印加されるまでに、０．０１〜
０．１ｓｅｃの時間が必要である。<Second Embodiment> In the above-described embodiment, when a bias is applied to the fixing device, the time from the rising of the constant current to the application of Vt is 0.01 to 0.01.
A time of 0.1 sec is required.
【００３８】従って、記録材先端からの長さＬａ＝（定
着ニップから接地電極までの長さ）＋プロセススピード
×（０．０１〜０．１ｓｅｃ）としたとき、記録材上長
さＬａまでは、バイアスを最適に変更できない範囲とな
る。Therefore, when the length La from the leading end of the recording material = (the length from the fixing nip to the ground electrode) + the process speed × (0.01 to 0.1 sec), the length La on the recording material is , The bias cannot be optimally changed.
【００３９】そこで本例は、こうした問題を解決するた
め、図３のような構成とした。すなわち、加圧ローラ１
０６はアルミ芯金のまわりに導電性の粒子を分散させた
シリコンゴム等の弾性体で覆われており、表層には導電
性の離型層がコートされている。芯金から表層までは導
電性がある。定着フィルム１０３と加圧ローラ１０６は
別々に導通経路が設けられ、図３では加圧ローラ１０６
が抵抗１０７を介して接地され、定着フィルム１０３に
高圧電源１０９からのバイアスが印加されている。即
ち、前記形態で示した接地電極１０５を加圧ローラ１０
６が兼ねている構成となる。Therefore, in this embodiment, in order to solve such a problem, the configuration as shown in FIG. 3 is adopted. That is, the pressure roller 1
Numeral 06 is covered with an elastic material such as silicon rubber in which conductive particles are dispersed around an aluminum core bar, and a surface layer is coated with a conductive release layer. There is conductivity from the core metal to the surface layer. The fixing film 103 and the pressure roller 106 are provided with separate conduction paths, and in FIG.
Are grounded via a resistor 107, and a bias from a high voltage power supply 109 is applied to the fixing film 103. That is, the ground electrode 105 shown in the above embodiment is
6 also serves as a configuration.
【００４０】このように定着フィルム１０３にバイアス
が印加され、フィルム１０３のトップ層から、記録材Ｐ
と加圧ローラ１０６の導電ゴム層を介してアースヘの電
流経路ができ、記録材Ｐに対するトナー拘束力が発生す
る。As described above, the bias is applied to the fixing film 103, and the recording material P
Then, a current path to the ground is formed through the conductive rubber layer of the pressure roller 106, and a toner binding force to the recording material P is generated.
【００４１】ここでバイアスを印加するに当たり、セン
サー１０８によって監視される記録材先端が定着ニップ
Ｎに達したならば、高圧電源１０９から１０μＡの定電
流が印加される。このとき加圧ローラ１０６に流れる漏
れ電流が、１０ｋΩの抵抗１０７にかかる電圧値とし
て、不図示のＣＰＵにモニターされており、その電圧値
Ｖ０から最適なバイアスＶｔを前記形態と同様に算出す
る。In applying the bias, if the leading end of the recording material monitored by the sensor 108 reaches the fixing nip N, a constant current of 10 μA is applied from the high voltage power supply 109. At this time, a leakage current flowing through the pressure roller 106 is monitored by a CPU (not shown) as a voltage value applied to the resistor 107 of 10 kΩ, and an optimum bias Vt is calculated from the voltage value V0 in the same manner as in the above embodiment.
【００４２】上記構成により、バイアスを最適化できな
い領域を、前記形態と比べて定着ニップＮから接地電極
１０５までの長さ分、短縮することができる。また通常
のプリントでは、記録材先端部分数ミリは余白領域であ
るので、上記制御ならば画像にほとんど影響を与えな
い。以上から記録材全域に渡って尾引き画像、オフセッ
ト画像の発生を防止することができた。With the above configuration, the region where the bias cannot be optimized can be shortened by the length from the fixing nip N to the ground electrode 105 as compared with the above embodiment. Also, in normal printing, a few millimeters of the leading end portion of the recording material is a margin area, and thus the above control has almost no effect on the image. As described above, it was possible to prevent the occurrence of the trailing image and the offset image over the entire area of the recording material.
【００４３】また、記録材Ｐとフィルム１０３のプライ
マ層との間に電位差を設ける別の構成として図４に示す
ように定着フィルム１０３のプライマ層を接地し、加圧
ローラ１０６にバイアスを印加する構成であっても同様
の効果がある。As another configuration for providing a potential difference between the recording material P and the primer layer of the film 103, the primer layer of the fixing film 103 is grounded and a bias is applied to the pressure roller 106 as shown in FIG. The same effect is obtained even with the configuration.
【００４４】〈画像形成装置例〉図６は画像形成装置の
一例の概略構成図である。本例の画像形成装置は電子写
真プロセス利用のレーザービームプリンターである。<Example of Image Forming Apparatus> FIG. 6 is a schematic structural view of an example of the image forming apparatus. The image forming apparatus of this embodiment is a laser beam printer using an electrophotographic process.
【００４５】１１は第１の像担持体としての回転ドラム
型の電子写真感光体（以下、感光ドラムと記す）であ
る。Reference numeral 11 denotes a rotating drum type electrophotographic photosensitive member (hereinafter, referred to as a photosensitive drum) as a first image carrier.
【００４６】この感光ドラム１１は矢示の時計方向に所
定の周速度（プロセススピード）をもって回転駆動さ
れ、その回転過程で一次帯電器１２によりマイナスの所
定の暗電位ＶD に一様に帯電処理される。[0046] The photosensitive drum 11 is rotated in the clockwise direction of arrow at a predetermined peripheral speed (process speed), uniformly charged to a predetermined dark potential V D of the negative by a primary charger 12 in the rotation process Is done.
【００４７】１３はレーザービームスキャナであり、不
図示の画像読取装置・ワードプロセッサ・コンピュータ
等のホスト装置から入力される目的の画像情報の時系列
電気デジタル画像信号に対応して変調されたレーザービ
ームＬを出力し、前記の回転感光ドラム１１の一様帯電
処理面を走査露光する。Reference numeral 13 denotes a laser beam scanner, which is a laser beam L modulated according to a time-series electric digital image signal of target image information input from a host device such as an image reading device, a word processor, and a computer (not shown). And scans and exposes the uniformly charged surface of the rotating photosensitive drum 11.
【００４８】このレーザービーム走査露光により、回転
感光ドラム１１の一様帯電処理面の露光部分は電位絶対
値が小さくなって明電位ＶL となり、回転感光ドラム１
１面に目的の画像情報に対応した静電潜像が形成されて
いく。次いでその潜像は現像器１４によりマイナスに帯
電した粉体トナーで反転現像（感光ドラム面のレーザー
露光明電位ＶL 部にトナーが付着）されてトナー画像と
して顕像化される。As a result of this laser beam scanning exposure, the exposed portion of the uniformly charged surface of the rotating photosensitive drum 11 has a reduced absolute potential value to a bright potential VL ,
An electrostatic latent image corresponding to the target image information is formed on one surface. Next, the latent image is subjected to reversal development (toner is adhered to the laser exposure light potential VL portion of the photosensitive drum surface) with the negatively charged powder toner by the developing device 14 to be visualized as a toner image.
【００４９】現像器１４は回転駆動される現像スリーブ
１４ａを有し、この現像スリーブ外周面にマイナスに帯
電したトナーの薄層がコートされて感光ドラム１１面と
対向し、現像スリーブ１４ａには絶対値が感光ドラム１
１面の潜像の暗電位ＶD よりも小さく、明電位ＶL より
も大きい現像バイアス電圧ＶDCが印加されていること
で、現像スリーブ１４ａ上のトナーが感光ドラム１１面
の潜像の明電位ＶL の部分にのみ転移して潜像が顕像化
（反転現像）される。The developing device 14 has a developing sleeve 14a which is driven to rotate. The outer peripheral surface of the developing sleeve is coated with a thin layer of negatively charged toner and faces the surface of the photosensitive drum 11, and the developing sleeve 14a Value is photosensitive drum 1
Smaller than the dark potential V D of the latent image of one side, by the development bias voltage V DC is applied greater than the bright potential V L, light of the latent image of the toner on the developing sleeve 14a is photosensitive drum 11 surface The latent image is transferred only to the potential VL and the latent image is visualized (reversal development).
【００５０】一方、給紙トレイ１５上に積載セットされ
ている第２の像担持体としての記録材Ｐが、給紙ローラ
１６の駆動により１枚ずつ繰り出し給送され、搬送ガイ
ド１７ａ、レジストローラ対１８、転写ガイド１７ｂを
経由して、感光ドラム１１とこれに当接させて転写バイ
アスを印加した転写部材としての転写ローラ１９との圧
接部である転写ニップ部ｍへ感光ドラム１１の回転と同
期どりされた適切なタイミングをもって給送され、該給
送記録材Ｐの面に感光ドラム１１面側のトナー画像が順
次に転写されていく。On the other hand, a recording material P as a second image carrier loaded and set on the paper feed tray 15 is fed out one by one by the driving of the paper feed roller 16, and is fed by a transport guide 17a and a registration roller. The transfer of the photosensitive drum 11 to a transfer nip portion m, which is a pressure contact portion between the photosensitive drum 11 and a transfer roller 19 as a transfer member to which a transfer bias is applied by contact with the photosensitive drum 11 via a transfer guide 17b. The recording material P is fed at an appropriate synchronized timing, and the toner image on the surface of the photosensitive drum 11 is sequentially transferred onto the surface of the fed recording material P.
【００５１】転写ニップ部ｍを通った記録材Ｐは、回転
感光ドラム１１面から分離され、搬送ガイド１７ｃを経
由して前記第一又は二の実施形態に示した定着装置Ｒに
導入されてトナー画像の定着処理を受け、排紙ローラ２
０に搬送されて排紙トレイ２１上へ出力される。The recording material P that has passed through the transfer nip m is separated from the surface of the rotating photosensitive drum 11 and introduced into the fixing device R shown in the first or second embodiment via the conveyance guide 17c, and the toner P After receiving the image fixing process, the discharge roller 2
0 and is output onto the discharge tray 21.
【００５２】なお、記録材分離後の回転感光ドラム１１
面はクリーニング装置２２で転写残りトナー等の感光ド
ラム面残留物の除去を受けて清浄面化されて繰り返して
作像に供される。The rotating photosensitive drum 11 after the recording material is separated
The surface is cleaned by the cleaning device 22 to remove residual toner such as residual toner on the surface of the photosensitive drum, and is repeatedly subjected to image formation.
【００５３】[0053]
【発明の効果】以上説明したように、本発明によれば、
環境変化によらずに最適なバイアスを印加することがで
き、トナー飛散や画像不良等を常に良好に防止すること
が可能な定着装置及び画像形成装置を提供できる。As described above, according to the present invention,
It is possible to provide a fixing device and an image forming apparatus that can apply an optimal bias regardless of environmental changes and can always prevent toner scattering, image defects, and the like satisfactorily.
【図面の簡単な説明】[Brief description of the drawings]
【図１】 本発明に係る第一の実施形態の定着装置を説
明する図FIG. 1 is a diagram illustrating a fixing device according to a first embodiment of the present invention.
【図２】 本発明に係る第一の実施形態の定着装置を説
明する図FIG. 2 is a diagram illustrating a fixing device according to a first embodiment of the present invention.
【図３】 本発明に係る第二の実施形態の定着装置を説
明する図FIG. 3 is a diagram illustrating a fixing device according to a second embodiment of the present invention.
【図４】 本発明に係る第二の実施形態の定着装置を説
明する図FIG. 4 is a diagram illustrating a fixing device according to a second embodiment of the invention.
【図５】 各環境下での適正バイアスの説明図FIG. 5 is an explanatory diagram of an appropriate bias under each environment.
【図６】 本発明に係る画像形成装置を説明する図FIG. 6 is a diagram illustrating an image forming apparatus according to the present invention.
１１ 感光ドラム １２ 一次帯電器 １４ 現像器 １４ａ現像スリーブ １５ 給紙トレイ １５ａアルミ基板 １５ｂ繊維 １６ 給紙ローラ １７ 搬送ガイド １８ａ，１８ｂ レジストローラ対 １９ａ，１９ｂ 転写ガイド ２０ 転写ローラ ２１ 搬送ガイド ２２ 排紙トレイ ２３ クリーニング装置 ４１ 定着入口ガイド ５１ 排紙ガイド １０２ヒータ １０３定着フィルム １０４加圧ローラ １０５電極 １０６加圧ローラ １０７抵抗 １０８センサー １０９高圧電源 １１０検知手段 Ｌ レーザービーム Ｎ 定着ニップ Ｐ 記録材 Ｒ 定着装置 Ｔ トナー ｍ 転写ニップ部 REFERENCE SIGNS LIST 11 photosensitive drum 12 primary charger 14 developing device 14a developing sleeve 15 paper feed tray 15a aluminum substrate 15b fiber 16 paper feed roller 17 transport guides 18a, 18b registration roller pair 19a, 19b transfer guide 20 transfer roller 21 transport guide 22 paper discharge tray 23 Cleaning Device 41 Fixing Entrance Guide 51 Discharge Guide 102 Heater 103 Fixing Film 104 Pressure Roller 105 Electrode 106 Pressure Roller 107 Resistance 108 Sensor 109 High Voltage Power Supply 110 Detecting Means L Laser Beam N Fixing Nip P Recording Material R Fixing Device T Toner m Transfer nip
Claims (8)
部材と加圧部材を有し、前記定着ニップで記録材を挟持
搬送して記録材上のトナー像を加熱・加圧して定着させ
る定着装置において、 前記加熱部材または前記加圧部材の少なくとも一方にバ
イアスを印加するバイアス印加手段と、 前記記録材に当接する電極と、 前記電極に流れる電流を検知する検知手段と、 を有し、前記記録材が前記定着ニップと前記電極との双
方に接触する位置に達したときの前記記録材を介して前
記電極に流れる電流を前記検知手段で検知し、この検知
結果に基づいて前記バイアス手段から前記加熱部材に印
加されるバイアスを変更することを特徴とする定着装
置。An image forming apparatus comprising: a heating member and a pressure member that press against each other to form a fixing nip; and a fixing device that nips and conveys the recording material by the fixing nip and heats and presses the toner image on the recording material to fix the toner image. The apparatus, comprising: a bias applying unit that applies a bias to at least one of the heating member and the pressing member; an electrode that contacts the recording material; and a detecting unit that detects a current flowing through the electrode. When the recording material reaches a position where the recording material contacts both the fixing nip and the electrode, a current flowing through the electrode through the recording material is detected by the detection unit. A fixing device, wherein a bias applied to the heating member is changed.
る請求項１記載の定着装置。2. The fixing device according to claim 1, wherein said electrode is grounded.
部材と加圧部材を有し、前記定着ニップで記録材を挟持
搬送して記録材上のトナー像を加熱・加圧して定着させ
る定着装置において、 前記記録材に当接する電極と、 前記電極にバイアスを印加するバイアス印加手段と、 前記加熱部材に流れる電流を検知する検知手段と、を有
し、前記記録材が前記加熱部材と前記電極との双方に接
触したときの記録材を介して該電極から該加熱部材にか
けて流れる電流を前記検知手段で検知し、この検知結果
に基づいて前記バイアス手段から前記電極に印加される
バイアスを変更することを特徴とする定着装置。3. A fixing device comprising a heating member and a pressure member which press against each other to form a fixing nip, wherein the fixing nip holds and conveys the recording material and heats and presses the toner image on the recording material to fix the toner image. An apparatus, comprising: an electrode in contact with the recording material; a bias application unit configured to apply a bias to the electrode; and a detection unit configured to detect a current flowing through the heating member. A current flowing from the electrode to the heating member through the recording material when the electrode comes into contact with both of the electrodes is detected by the detection unit, and a bias applied from the bias unit to the electrode is changed based on the detection result. A fixing device.
とする請求項３記載の定着装置。4. The fixing device according to claim 3, wherein said heating member is grounded.
部材と加圧部材を有し、前記定着ニップで記録材を挟持
搬送して記録材上のトナー像を加熱・加圧して定着させ
る定着装置において、 前記加熱部材または前記加圧部材の一方にバイアスを印
加するバイアス印加手段と、 前記加熱部材または前記加圧部材のバイアスが印加され
ていない方に流れる電流を検知する検知手段と、 を有し、前記記録材が前記定着ニップに導入されて前記
加熱部材と前記加圧部材の双方と接触したときの前記記
録材を介して前記加熱部材と前記加圧部材との間に流れ
る電流を前記検知手段で検知し、この検知結果に基づい
て前記バイアス手段から前記加熱部材または前記加圧部
材に印加されるバイアスを変更することを特徴とする定
着装置。5. A fixing device comprising a heating member and a pressure member which press against each other to form a fixing nip, wherein the fixing nip holds and conveys a recording material to fix the toner image on the recording material by heating and pressing. In the apparatus, bias applying means for applying a bias to one of the heating member or the pressing member, and detecting means for detecting a current flowing to a side of the heating member or the pressing member to which no bias is applied, A current flowing between the heating member and the pressing member via the recording material when the recording material is introduced into the fixing nip and comes into contact with both the heating member and the pressing member. A fixing device, wherein the fixing unit detects the detection unit and changes a bias applied to the heating member or the pressing member from the bias unit based on a result of the detection.
包する回転部材からなることを特徴とする請求項１乃至
５の何れか１項に記載の定着装置。6. The fixing device according to claim 1, wherein the heating member includes a heater and a rotating member including the heater.
ップで挟持搬送している途中又は前記電流を検知した記
録材の次の記録材を定着ニップに導入するときに前記バ
イアスの変更を行うことを特徴とする請求項１乃至６の
何れか１項に記載の像加熱装置。7. The method according to claim 7, wherein the bias is changed while the recording material having detected the current is being nipped and conveyed by the fixing nip or when the recording material next to the recording material having detected the current is introduced into the fixing nip. The image heating apparatus according to claim 1, wherein the image heating is performed.
と、該トナー像を加熱して記録材上に定着させる像定着
手段とを有する画像形成装置において、 該像定着手段として請求項１乃至７の何れか１項に記載
の像加熱装置を備えたことを特徴とする画像形成装置。8. An image forming apparatus comprising: an image forming means for forming a toner image on a recording material; and an image fixing means for heating the toner image to fix the toner image on the recording material. An image forming apparatus comprising the image heating device according to any one of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11026199A JP2000221819A (en) | 1999-02-03 | 1999-02-03 | Fixing device and image forming device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11026199A JP2000221819A (en) | 1999-02-03 | 1999-02-03 | Fixing device and image forming device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000221819A true JP2000221819A (en) | 2000-08-11 |
Family
ID=12186819
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11026199A Pending JP2000221819A (en) | 1999-02-03 | 1999-02-03 | Fixing device and image forming device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000221819A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006195004A (en) * | 2005-01-11 | 2006-07-27 | Canon Inc | Image forming apparatus and its power supply control method |
| JP2017219790A (en) * | 2016-06-10 | 2017-12-14 | 京セラドキュメントソリューションズ株式会社 | Image forming apparatus |
-
1999
- 1999-02-03 JP JP11026199A patent/JP2000221819A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006195004A (en) * | 2005-01-11 | 2006-07-27 | Canon Inc | Image forming apparatus and its power supply control method |
| JP4592079B2 (en) * | 2005-01-11 | 2010-12-01 | キヤノン株式会社 | Image forming apparatus |
| JP2017219790A (en) * | 2016-06-10 | 2017-12-14 | 京セラドキュメントソリューションズ株式会社 | Image forming apparatus |
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