JPH08146677A - Image forming method - Google Patents
Image forming methodInfo
- Publication number
- JPH08146677A JPH08146677A JP6289899A JP28989994A JPH08146677A JP H08146677 A JPH08146677 A JP H08146677A JP 6289899 A JP6289899 A JP 6289899A JP 28989994 A JP28989994 A JP 28989994A JP H08146677 A JPH08146677 A JP H08146677A
- Authority
- JP
- Japan
- Prior art keywords
- image forming
- charging
- current
- image
- constant voltage
- 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.)
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- Developing For Electrophotography (AREA)
- Electrostatic Charge, Transfer And Separation In Electrography (AREA)
- Control Or Security For Electrophotography (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、電子写真装置、レーザ
ービームスプリンター、普通紙ＦＡＸ等の、直接帯電を
用いる電子写真応用分野に広く用いることができる画像
形成方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method which can be widely used in electrophotographic application fields using direct charging, such as electrophotographic apparatuses, laser beam sprinters, and plain paper FAX.
【０００２】[0002]
【従来の技術】電子写真プロセスを用いる画像形成方法
において、帯電手段としては、従来、コロナ放電装置が
一般的であった。しかしながら最近においては、電源の
低圧化が図れる、オゾンの発生が極めて微量である等の
長所も有していることから、ローラ型やブラシ型の導電
部材を感光体に接触させる直接帯電装置が採用されつつ
ある。2. Description of the Related Art In an image forming method using an electrophotographic process, a corona discharge device has been generally used as a charging means. However, in recent years, the direct charging device for contacting a roller-type or brush-type conductive member with the photoconductor has been adopted because it has advantages such as low power supply voltage and extremely small amount of ozone generation. Is being done.
【０００３】ここで、印加する高圧をＤＣ成分のみとす
るか、あるいはそれにＡＣ成分を重畳させる方法があ
る。Here, there is a method in which the high voltage to be applied is only a DC component or an AC component is superposed on it.
【０００４】ＡＣを重畳させる系では、感光体への流れ
込み電流が飛躍的に増加することによる感光体表面の摩
耗、トナーの付着といった画像劣化の問題、また、ＡＣ
成分が感光体や周辺部材を振動させることにより耳触り
ノイズが発生するといった問題がある。また、画像露光
部を現像剤にて可視化する現像方法、いわゆる反転現像
においては、感光体の膜厚が摩耗して薄くなった時にカ
ブリが生じやすいという問題があった。In a system in which AC is superimposed, the problem of image deterioration such as abrasion of the surface of the photosensitive member and adhesion of toner due to a dramatic increase in current flowing into the photosensitive member, and AC
There is a problem in that the components vibrate the photoconductor and peripheral members to cause noise to the ear. Further, in the developing method in which the image-exposed area is visualized with a developer, that is, so-called reversal development, there is a problem that fogging is likely to occur when the film thickness of the photoconductor is worn and thinned.
【０００５】一方、ＤＣ成分のみを印加する系では、Ａ
Ｃ成分を重畳させる場合に比べて表面の摩耗、トナー付
着の程度は小さいが、反転現像時のカブリにおける感光
体膜厚のラチチュードがより狭いという問題があった。On the other hand, in a system in which only the DC component is applied, A
The degree of surface abrasion and toner adhesion is smaller than when the C component is superposed, but there is a problem that the latitude of the photoconductor film thickness due to fogging during reversal development is narrower.
【０００６】[0006]
【発明が解決しようとする課題】本発明は、上述したよ
うな直接帯電、特にＤＣ成分のみを印加する場合に発生
する画像カブリを防止する、常に安定して高画質の得ら
れる画像形成方法を提供することを目的としている。SUMMARY OF THE INVENTION The present invention provides an image forming method capable of always obtaining stable and high image quality, which prevents image fog which occurs when direct charging as described above, especially when only DC component is applied. It is intended to be provided.
【０００７】[0007]
【課題を解決するための手段】すなわち本発明は、少な
くとも感光体に直接帯電部材を当接して該感光体を帯電
させる帯電工程、該感光体の画像露光部を現像剤にて可
視化する現像工程を有する画像形成方法において、該帯
電部材が感光体の非画像形成領域に対応している時に該
帯電部材を直流定電圧制御し、その時の感光体膜厚に応
じた直流電流量を検知し、該帯電部材が感光体の画像形
成領域に対応している時は上記検知した直流電流量に応
じた直流電圧で該帯電部材を直流定電圧制御して感光体
の膜厚減少に伴って表面電位を徐々に下げていくと共
に、現像剤供給体への印加電圧も下げていくように制御
する、ことを特徴とする画像形成方法である。That is, the present invention provides a charging step of charging a photosensitive member by directly contacting at least a charging member to the photosensitive member, and a developing step of visualizing an image-exposed portion of the photosensitive member with a developer. In the image forming method having the above, when the charging member corresponds to the non-image forming region of the photoconductor, the charging member is subjected to DC constant voltage control, and the amount of DC current according to the photoconductor film thickness at that time is detected, When the charging member corresponds to the image forming area of the photosensitive member, the charging member is controlled to a constant DC voltage with a DC voltage corresponding to the detected amount of DC current, and the surface potential is gradually increased as the film thickness of the photosensitive member is reduced. The image forming method is characterized in that the voltage applied to the developer supplying body is controlled so as to be lowered as well.
【０００８】以下、本発明を詳しく説明する。The present invention will be described in detail below.
【０００９】ＤＣ印加の直接帯電においては、帯電部材
と感光体の接点近傍に形成される微小ギャップで起こる
放電により、帯電が行われる。この時の感光体表面電位
Ｖｄは、 Ｖｄ＝ＶDC−ＶTH で表される。ここでＶDCは帯電部材への直流印加電圧、
ＶTHは放電開始電圧である。In DC direct charging, charging is performed by discharge occurring in a minute gap formed near the contact point between the charging member and the photosensitive member. The photoconductor surface potential Vd at this time is represented by Vd = V DC −V TH . Where V DC is the DC voltage applied to the charging member,
V TH is the discharge start voltage.
【００１０】一方、感光体は耐久使用により表面が摩耗
し、膜厚が薄くなっていくが、これに伴って感光体への
流れ込み電流が大きくなり、表面電位が上昇するという
現象がある。On the other hand, the surface of the photoconductor is worn down due to long-term use, and the film thickness is reduced. As a result, the current flowing into the photoconductor is increased and the surface potential is increased.
【００１１】このため従来技術として、帯電部材が感光
体の非画像形成領域に対応している時に帯電部材を直流
定電圧制御し、その時の感光体膜厚に応じた直流電流量
を検知し、帯電部材が感光体の画像形成領域に対応して
いる時は上記検知した直流電流量に応じた直流電圧で帯
電部材を直流定電圧制御することにより、感光体が膜厚
減少しても表面電位を一定に保つ手段が提案されてい
る。For this reason, as a conventional technique, when the charging member corresponds to the non-image forming area of the photoconductor, the charging member is subjected to DC constant voltage control, and the amount of DC current according to the film thickness of the photoconductor at that time is detected to charge. When the member corresponds to the image forming area of the photoconductor, the surface potential is kept constant even if the film thickness of the photoconductor is reduced by controlling the charging member with a constant DC voltage with the DC voltage corresponding to the detected DC current amount. A means of keeping it at is proposed.
【００１２】しかしながら、このような条件下では前述
したように感光体に帯電直後に高い電圧がかかること、
及び、耐久使用により表面に微細な荒れを生じ、その局
所的に膜厚が薄い部分の電位が高くなることにより、基
板からのキャリアの注入を受けやすくなる。However, under such conditions, as described above, a high voltage is applied to the photoconductor immediately after charging,
Further, due to durable use, the surface becomes finely roughened, and the potential of the locally thin portion becomes high, so that carriers are easily injected from the substrate.
【００１３】このため、反転現像プロセスを用いた場合
に白地部のカブリを生じやすい。特に、耐久使用によっ
て感光体の膜厚が減少した時にカブリが生じやすくなる
ため、感光体の寿命を著しく短縮させてしまう結果とな
る。Therefore, when the reversal development process is used, the fog in the white background portion is likely to occur. In particular, fogging is likely to occur when the film thickness of the photoconductor is reduced due to durable use, resulting in a marked shortening of the life of the photoconductor.
【００１４】これを防止するために感光体の初期膜厚を
必要以上に厚くしてもよいが、その場合、解像度の低
下、膜の均一性、製造コスト等の不具合が生じ、好まし
くない。In order to prevent this, the initial film thickness of the photoconductor may be made thicker than necessary, but in that case, problems such as deterioration of resolution, film uniformity, and manufacturing cost occur, which is not preferable.
【００１５】このような点に鑑み、本発明においては膜
厚が減少した時のキャリアの注入を抑えるために、電界
強度の上昇をなくす、もしくは極めて小さく抑える点に
特徴がある。In view of such a point, the present invention is characterized in that the increase of the electric field strength is eliminated or suppressed to be extremely small in order to suppress the carrier injection when the film thickness is reduced.
【００１６】すなわち、直接帯電部材が感光体の非画像
形成領域に対応している時に該帯電部材を直流定電圧制
御し、その時の感光体膜厚に応じた直流電流量を検知す
る。ここで電流量から推定される膜厚に対応し、適切な
電界強度で、且つ必要十分な電位コントラストが得られ
る程度までの表面電位をあらかじめ設定しておき、上記
電流量との対応を装置制御部にメモリーとして持たせ
る。That is, when the direct charging member corresponds to the non-image forming area of the photosensitive member, the charging member is subjected to direct current constant voltage control, and the amount of direct current corresponding to the film thickness of the photosensitive member at that time is detected. Here, the surface potential is set in advance corresponding to the film thickness estimated from the amount of electric current, with an appropriate electric field strength, and to the extent that a necessary and sufficient potential contrast can be obtained, and the device is controlled to correspond to the above amount of electric current. Have a part as a memory.
【００１７】次に該帯電部材が感光体の画像形成領域に
対応している時は上記対応にもとずいた直流電流量にて
該帯電部材を直流定電圧制御することにより感光体の膜
厚減少に伴って表面電位を徐々に下げていくことができ
る。Next, when the charging member corresponds to the image forming area of the photosensitive member, the film thickness of the photosensitive member is reduced by controlling the charging member with a constant DC voltage with the amount of direct current based on the above correspondence. With this, the surface potential can be gradually lowered.
【００１８】一方、表面電位を下げることにより暗部電
位と現像バイアスとのコントラストが小さくなり、カブ
リを生じやすくなってしまう。従って、本発明において
は、現像バイアスも表面電位と共に下げていくように制
御する。On the other hand, by lowering the surface potential, the contrast between the dark part potential and the developing bias becomes small, and fog is likely to occur. Therefore, in the present invention, the developing bias is controlled so as to decrease with the surface potential.
【００１９】これに伴って、当然のことながら明部電位
との現像コントラストも小さくなるが、これに関して
は、元々画像濃度の現像コントラストに対する依存性が
小さい領域であり、さらに初期の段階で十分に余裕のあ
るコントラスト設定とすることで弊害を回避することが
できる。Along with this, naturally, the development contrast with the bright portion potential also decreases, but in this respect, the dependence of the image density on the development contrast is originally small, and it is sufficient in the initial stage. The adverse effect can be avoided by setting the contrast with a margin.
【００２０】[0020]
【実施例】以下の実施例１乃至同４は前記特許請求の範
囲の請求項１に記載の発明の画像形成装置についての実
施例である。EXAMPLES Examples 1 to 4 below are examples of the image forming apparatus of the invention described in claim 1 of the appended claims.
【００２１】〈実施例１〉（図１〜図１０） （１）画像形成装置例 図１は本発明に従う画像形成装置の一例の概略構成を示
している。<Embodiment 1> (FIGS. 1 to 10) (1) Example of Image Forming Apparatus FIG. 1 shows a schematic structure of an example of an image forming apparatus according to the present invention.
【００２２】１は被帯電体としての像担持体であり、本
例のものはアルミニウム等の導電性基体層１ｂと、その
外周面に形成した光導電層１ａを基本構成層とするドラ
ム型の電子写真感光体である。支軸１ｄを中心に図面上
時計方向に所定の周速度（プロセススピード）をもって
回転駆動される。本実施例では、１０５ｍｍ／ｓｅｃで
ある。Reference numeral 1 denotes an image bearing member as a member to be charged, and this embodiment is of a drum type having a conductive base layer 1b such as aluminum and a photoconductive layer 1a formed on the outer peripheral surface thereof as a basic constituent layer. It is an electrophotographic photoreceptor. It is rotationally driven around the support shaft 1d at a predetermined peripheral speed (process speed) in the clockwise direction in the drawing. In this embodiment, it is 105 mm / sec.
【００２３】２はこの感光体１面に接して感光体面を所
定の極性・電位に一様に一次帯電処理する接触帯電部材
であり、本例はローラタイプのもの（帯電ローラ）であ
る。帯電ローラ２は中心芯金２ｃと、その外周に形成し
た導電層２ｂと、更にその外周に順次形成した２層の抵
抗層２ａ2 ・２ａ1 とから成り、芯金２ｃの両端部を不
図示の軸受部材に回転自由に軸受させてドラム型の感光
体１に並行に配置して不図示の押圧手段で感光体１面に
対して所定の押圧力をもって圧接され、感光体１の回転
駆動に伴い従動回転する。Reference numeral 2 denotes a contact charging member which is in contact with the surface of the photosensitive member 1 and which uniformly performs a primary charging process on the surface of the photosensitive member so as to have a predetermined polarity and potential. In this example, a contact type charging member is a roller type. The charging roller 2 consists of a center core metal 2c, a conductive layer 2b formed on its outer periphery, further formed successively the two layers of the resistive layer 2a 2 · 2a 1 Tokyo on its outer circumference, not shown to opposite ends of the core metal 2c The bearing member is rotatably rotatably arranged in parallel with the drum type photoconductor 1 and is pressed against the surface of the photoconductor 1 by a pressing means (not shown) with a predetermined pressing force to rotate the photoconductor 1. Along with the rotation.
【００２４】而して、電源３から摺動接点３ａを介して
芯金２ｃに所定の直流（ＤＣ）バイアスが印加されるこ
とで回転感光体１の周面が所定の極性・電位に接触帯電
（一次帯電）される。Then, a predetermined direct current (DC) bias is applied from the power source 3 to the core metal 2c through the sliding contact 3a, so that the peripheral surface of the rotating photoconductor 1 is contact-charged to a predetermined polarity and potential. (Primary charging).
【００２５】帯電部材２で均一に帯電処理を受けた感光
体１面は次いで露光手段１０により目的画像情報の露光
Ｌを受けることで、その周面に目的の画像情報に対応し
た静電潜像が形成される。The surface of the photosensitive member 1 which has been uniformly charged by the charging member 2 is then subjected to the exposure L of the target image information by the exposure means 10, so that an electrostatic latent image corresponding to the target image information is formed on the peripheral surface thereof. Is formed.
【００２６】本例装置における露光手段１０は、レーザ
ービーム走査露光である。１６の反射ミラーにてレーザ
ービームが感光体に照射される。The exposure means 10 in the apparatus of this embodiment is a laser beam scanning exposure. The laser beam is applied to the photoconductor by the 16 reflecting mirrors.
【００２７】感光体１面の形成潜像は次いで現像手段１
１によりトナー画像として順次に可視像化されていく。
１１ａはトナー、１１ｂは表面にトナー層を形成しバイ
アス電圧を印加することで対向する感光体１にトナー現
像を行うトナー供給体である。本例では画像露光部にト
ナー現像を行う、いわゆる反転現像が適用される。この
トナー画像は、次いで、転写手段１２により不図示の給
紙手段部から感光体１の回転と同期どりされて適正なタ
イミングをもって感光体１と転写手段１２との間の転写
部へ搬送された転写材１４の面に順次に転写されてい
く。本例の転写手段１２は転写ローラであり、転写材１
４の裏からトナーと逆極性の帯電を行なうことで感光体
１面側のトナー画像が転写材１４の表面側に転写されて
いく。The latent image formed on the surface of the photosensitive member 1 is then developed by the developing means 1.
By 1, the toner images are sequentially visualized.
Reference numeral 11a is a toner, and 11b is a toner supply member that forms a toner layer on the surface and applies a bias voltage to develop the toner on the opposing photoconductor 1. In this example, so-called reversal development, in which toner development is performed on the image exposure portion, is applied. The toner image is then conveyed from the sheet feeding section (not shown) by the transfer section 12 to the transfer section between the photoreceptor 1 and the transfer section 12 at an appropriate timing in synchronization with the rotation of the photosensitive body 1. The images are sequentially transferred onto the surface of the transfer material 14. The transfer means 12 of this example is a transfer roller, and the transfer material 1
The toner image on the surface of the photoconductor 1 is transferred to the surface of the transfer material 14 by charging the opposite polarity of the toner from the back side of 4.
【００２８】トナー画像の転写を受けた転写材１４は感
光体１面から分離されて不図示の像定着手段へ搬送され
て像定着を受け、画像形成物として出力される。或いは
裏面にも像形成するものでは転写部への再搬送手段へ搬
送される。The transfer material 14 to which the toner image has been transferred is separated from the surface of the photosensitive member 1 and is conveyed to an image fixing means (not shown) to be subjected to image fixing and output as an image formed product. Alternatively, when the image is formed on the back side, the image is conveyed to the re-conveying unit to the transfer unit.
【００２９】像転写後の感光体１面はクリーニング手段
１３で転写残りトナー等の付着汚染物の除去を受けて清
浄面化され、更に除電露光装置１５により除電されて、
繰り返して作像に供される。After the image transfer, the surface of the photosensitive member 1 is cleaned by the cleaning means 13 to remove adhering contaminants such as untransferred toner, and is then cleaned by the discharging exposure device 15 to remove the charge.
It is repeatedly used for image formation.
【００３０】なお、本発明においては反転現像であるた
め、転写後の感光体表面は少くとも帯電電位より低くな
っており、従って除電露光１５は省略させることも可能
である。In the present invention, since the reversal development is performed, the surface of the photoconductor after transfer is at least lower than the charging potential, and therefore, the static elimination exposure 15 can be omitted.
【００３１】（２）帯電部材２の各種形態例 ローラタイプの帯電部材２は面移動駆動される被帯電体
としての感光体１に従動回転させてもよいし、非回転の
ものとさせてもよいし、感光体１の面移動方向に順方向
又は逆方向に所定の周速度をもって積極的に回転駆動さ
せるようにしてもよい。(2) Various Embodiments of Charging Member 2 The roller-type charging member 2 may be driven to rotate according to the photosensitive member 1 as a member to be charged which is driven to move, or may not be rotated. Alternatively, the photosensitive member 1 may be positively rotationally driven in the forward or reverse direction of the surface moving direction at a predetermined peripheral speed.
【００３２】帯電部材２はローラタイプ以外にも、ブレ
ード状タイプ・ブロック状タイプ・ブラシ状タイプ・ロ
ッド状タイプ・ベルト状タイプなどの形態に構成でき
る。In addition to the roller type, the charging member 2 can be configured in a blade type, a block type, a brush type, a rod type, a belt type or the like.
【００３３】（３）シーケンス 図２は図１の装置の動作シーケンス例である。本例は２
枚連続プリントの場合を示している。(3) Sequence FIG. 2 shows an example of an operation sequence of the apparatus shown in FIG. This example is 2
The case of continuous printing on one sheet is shown.
【００３４】．プリント（コピー）開始信号にもとづ
き、それまでスタンバイ状態にある装置の感光体１（以
下、ドラムと記す）の回転駆動が開始されて前回転期間
が開始される。このドラム１の回転開始と同時に除電露
光１５がＯＮとなり、区間Ａ１においてドラム１の一周
面以上が除電される。.. Based on the print (copy) start signal, the rotation drive of the photosensitive member 1 (hereinafter, referred to as a drum) of the apparatus which has been in the standby state until then is started to start the pre-rotation period. At the same time when the rotation of the drum 1 is started, the static elimination exposure 15 is turned on, and static electricity is discharged from one peripheral surface or more of the drum 1 in the section A1.
【００３５】．次に接触帯電部材である帯電ローラ２
に対する一次帯電バイアスであるＤＣバイアスがＯＮと
なる。.. Next, the charging roller 2 which is a contact charging member
The DC bias, which is the primary charging bias for, is turned on.
【００３６】．この一次帯電バイアスは始めに区間Ｂ
１で定電圧制御され、その間にＤＣ電流の検知がなさ
れ、次に該検知したＤＣ電流に対応した帯電ローラＤＣ
定電圧制御がなされる。.. This primary charging bias begins with section B
1, constant voltage control is performed, DC current is detected during that period, and then charging roller DC corresponding to the detected DC current is detected.
Constant voltage control is performed.
【００３７】画像形成が始まるまでがドラム１の前回転
期間であり、その間のドラム１面は非画像形成領域面で
あり、従って帯電ローラ２はドラム１の非画像形成領域
面に対応している前回転期間の区間Ｂ１において帯電ロ
ーラＤＣ定電圧制御がなされ、このときのＤＣ電流の検
知と一次電圧補正（帯電ローラ２に対する一次帯電バイ
アス補正）がなされる。The period before the image formation starts is the pre-rotation period of the drum 1, and the surface of the drum 1 during that period is the non-image forming area surface, and therefore the charging roller 2 corresponds to the surface of the non-image forming area of the drum 1. The charging roller DC constant voltage control is performed in the section B1 of the pre-rotation period, and the DC current at this time is detected and the primary voltage correction (primary charging bias correction for the charging roller 2) is performed.
【００３８】．一次補正電圧で帯電ローラＤＣ定電圧
制御が始まったら画像露光画像信号に応じたレーザー露
光による１枚目の画像形成が行なわれる。帯電ローラ２
はドラム１の画像形成領域面に対応しており、該ドラム
１面をＤＣ定電圧制御状態にて帯電処理している。.. When the charging roller DC constant voltage control is started with the primary correction voltage, the first image is formed by laser exposure according to the image exposure image signal. Charging roller 2
Corresponds to the surface of the image forming area of the drum 1, and the surface of the drum 1 is charged in the DC constant voltage control state.
【００３９】．同時にトナー供給体へ印加するバイア
ス電圧のＤＣ成分も、で検知したＤＣ電流に対応した
補正電圧でＤＣ定電圧制御がなされる。.. At the same time, the DC component of the bias voltage applied to the toner supplier is also subjected to DC constant voltage control with a correction voltage corresponding to the DC current detected by.
【００４０】．１枚目のプリントについての画像形成
が終了し、次の２枚目のプリントについての画像形成が
開始されるまでの間の所謂紙間のドラム面は非画像形成
領域面であり、本実施例ではこの紙間でも再び帯電ロー
ラ２のＤＣ定電圧制御・ＤＣ電流検知・ＤＣ定電圧制御
を実行させている。.. A so-called drum surface between sheets until the image formation for the first print is completed and the image formation for the next second print is started is a non-image formation area surface. Then, the DC constant voltage control, the DC current detection, and the DC constant voltage control of the charging roller 2 are executed again during this sheet interval.
【００４１】即ち、１枚目のプリントが終了したら一次
帯電バイアスを紙間の区間Ｂ２において再び帯電ローラ
ＤＣ定電圧制御となし、ＤＣ電流検知を実行させ、次い
でその検知ＤＣ電流に応じた帯電ローラ定電圧制御を実
行させて２枚目のプリントについての画像形成を実行さ
せている。That is, when the printing of the first sheet is completed, the primary charging bias is again set to the charging roller DC constant voltage control in the section B2 between the sheets, the DC current detection is executed, and then the charging roller corresponding to the detected DC current. The constant voltage control is executed and the image formation for the second print is executed.
【００４２】３枚以上の連続プリントのときも各紙間に
おいて同様に帯電ローラＤＣ定電圧制御・ＤＣ電流検知
・ＤＣ定電圧制御のシーケンスを行なう。Even when three or more sheets are continuously printed, the charging roller DC constant voltage control / DC current detection / DC constant voltage control sequence is similarly performed between the respective sheets.
【００４３】．最終枚目のプリントの画像形成が終了
したらドラム１は後回転期間に入り、この後回転期間の
区間Ａ２においてドラム１の一周面以上の除電露光１５
がなされて除電され、ドラム１の回転と除電露光がＯＦ
Ｆとなり、装置は次のプリント開始信号の入力までスタ
ンバイ状態に入る。.. When the image formation of the final print is completed, the drum 1 enters the post-rotation period, and in the section A2 of the post-rotation period, the static elimination exposure 15 on one circumferential surface or more of the drum 1 is performed.
Is removed and the charge is removed, and the rotation of the drum 1 and the charge removal exposure are OF
The status becomes F, and the apparatus enters the standby state until the next print start signal is input.
【００４４】上記の構成において、耐久によってドラム
表面が削れて感光体膜厚が薄くなった場合には帯電ロー
ラ２がドラム１の非画像形成領域面に対応しているとき
になされているＤＣ定電圧制御期間Ｂ１やＢ２の検知Ｄ
Ｃ電流が高くなり、その検知ＤＣ電流に応じた低下補正
電圧での帯電ローラＤＣ定電圧制御のもとでドラム１の
画像形成領域面に対する帯電処理が帯電ローラ２により
なされて画像形成が実行される。かつ、検知ＤＣ電流に
応じた低下補正電圧でのトナー供給体へのトナー現像が
実行される。In the above structure, when the surface of the drum is scraped due to the durability and the film thickness of the photoconductor becomes thin, the DC constant performed when the charging roller 2 corresponds to the surface of the non-image forming area of the drum 1. Detection D of voltage control period B1 or B2
The C current becomes high, and the charging roller 2 performs a charging process on the image forming area surface of the drum 1 under the constant voltage control of the charging roller DC with a decrease correction voltage according to the detected DC current, and image formation is executed. It At the same time, the toner development on the toner supply body is executed with the lowered correction voltage according to the detected DC current.
【００４５】（４）電圧補正方法 感光体１としては負極性ＯＰＣドラムを用いた。具体的
には半導体レーザー光源に感度を有するアゾ顔料を樹脂
に分散したＣＧＬ（キャリア発生層）と、トリフェニル
アミン系化合物を樹脂に溶解したＣＴＬ（キャリア輸送
層）とを積層したものである。(4) Voltage Correction Method As the photoreceptor 1, a negative polarity OPC drum was used. Specifically, it is a laminate of CGL (carrier generation layer) in which an azo pigment having sensitivity to a semiconductor laser light source is dispersed in resin, and CTL (carrier transport layer) in which a triphenylamine compound is dissolved in resin.
【００４６】帯電ローラ２は、図１に層構成模型を示し
たように、芯金２ｃの上にＥＰＤＭ等の１０4 〜１０5
Ωｃｍの導電ゴム層２ｂを設け、その上にヒドリンゴム
等からなる１０7 〜１０9 Ωｃｍ程度の中抵抗層２ａ2
を設け、その上にトレジン（注：帝国化学（株）の商
標）等のナイロン系物質からなる１０7 〜１０10Ωｃｍ
のブロッキング層２ａ1 を表層として設けた、硬度がＡ
ｓｋｅｒ−Ｃ測定で５０°〜７０°程度のものを用い
た。そしてこの帯電ローラ２を感光ドラム１に総圧１６
００ｇで当接させ、従動回転させて帯電を行った。As shown in the layer structure model in FIG. 1, the charging roller 2 has 10 4 to 10 5 of EPDM or the like on the core metal 2c.
The conductive rubber layer 2b of the [Omega] cm is provided, the resistance layer 2a 2 in the order of 10 7 to 10 9 [Omega] cm made of hydrin or the like thereon
Is provided, and 10 7 to 10 10 Ωcm made of nylon-based material such as resin (Note: trademark of Teikoku Kagaku Co., Ltd.)
With a blocking layer 2a 1 as a surface layer having a hardness of A
The one having a sker-C measurement of about 50 ° to 70 ° was used. The charging roller 2 is applied to the photosensitive drum 1 with a total pressure of 16
It was contacted at 00 g and was driven to rotate for charging.
【００４７】この感光体のＣＴＬの膜厚を変えて、１４
５０Ｖの直接電圧を印加した時の表面電位、及び電流を
図３に示す。このようにＣＴ膜厚が減少すると共に直流
電流が増加し、表面電位も上昇する。By changing the thickness of the CTL of this photoconductor,
FIG. 3 shows the surface potential and current when a direct voltage of 50 V was applied. Thus, as the CT film thickness decreases, the direct current increases and the surface potential also increases.
【００４８】本実施例では、感光体の初期ＣＴ膜厚を２
６μとし、表面電位を７５０Ｖになるように設定した。In this embodiment, the initial CT film thickness of the photoconductor is set to 2
The surface potential was set to 750 V and 6 μ.
【００４９】さらに耐久使用により膜厚が減少した時の
制御電位を図４に示すように変化させる。この時にそれ
ぞれの膜厚において必要な直流電流値も図４に示す。Further, the control potential when the film thickness is reduced by durable use is changed as shown in FIG. The DC current value required for each film thickness at this time is also shown in FIG.
【００５０】すなわち、特定定電圧印加のみの場合は表
面電位は図３のように推移するが、本発明の定電圧印加
時の直流電流量を検知し、その電流量に応じて印加電圧
を補正して、より表面電位を下げることで過度の電界強
度を抑えることができる。なお、図５に本実施例におけ
る通紙プリント耐久でＣＴの膜厚がどのように変化する
かを示した。That is, when only a specific constant voltage is applied, the surface potential changes as shown in FIG. 3, but the amount of direct current when the constant voltage of the present invention is applied is detected, and the applied voltage is corrected according to the amount of current. By further lowering the surface potential, excessive electric field strength can be suppressed. It is to be noted that FIG. 5 shows how the film thickness of CT changes with the durability of the paper-passing print in this embodiment.
【００５１】一方、トナー現像における印加バイアスの
ＤＣ成分も、前記検知電流に応じて補正され定電圧制御
される。その具体例を図６に示す。On the other hand, the DC component of the applied bias in the toner development is also corrected according to the detected current and is subjected to constant voltage control. A specific example thereof is shown in FIG.
【００５２】このように、本実施例では６万枚までの耐
久プリントテストを行ったが、カブリの発生もなく良好
な画像を維持していた。上記の表面電位、現像印加バイ
アスや画像の推移などをまとめて表１に示す。As described above, in this embodiment, the durable print test was performed up to 60,000 sheets, but a good image was maintained without causing fog. The above surface potential, development applied bias, image transition, etc. are summarized in Table 1.
【００５３】[0053]
【表１】 [Table 1]
【００５４】（比較例１）実施例１と同様の装置を用
い、感光体の表面電位を耐久中一定に保つような制御を
行った。現像バイアスについても変化させなかった。(Comparative Example 1) Using the same apparatus as in Example 1, control was performed so that the surface potential of the photosensitive member was kept constant during the endurance. The developing bias was not changed either.
【００５５】その結果、３万枚付近から感光体表面の微
細な摺刷傷を反映したカブリが画像に現われるようにな
った。As a result, from around 30,000 sheets, fogging reflecting fine scratches on the surface of the photoconductor appeared in the image.
【００５６】（比較例２）実施例１と同様の装置を用
い、感光体の表面電位を耐久と共に下げていく制御を行
うが、現像バイアスについては変化させなかった。(Comparative Example 2) Using the same apparatus as in Example 1, the surface potential of the photosensitive member was controlled to decrease with durability, but the developing bias was not changed.
【００５７】その結果、５万枚付近から反転カブリが生
じはじめると共に、転写の影響を次の帯電で十分に消去
できないことから生ずるゴースト画像も見られた。As a result, reversal fog started to occur from around 50,000 sheets, and a ghost image caused by the fact that the influence of transfer could not be sufficiently erased by the next charging was also observed.
【００５８】（実施例２）実施例１のシーケンスに対
し、帯電ローラのＤＣ定電圧制御、ＤＣ電流検知を感光
体の前回転にのみ行い、連続プリントにおける紙間での
制御は省略した。(Embodiment 2) In the sequence of Embodiment 1, the DC constant voltage control of the charging roller and the DC current detection are performed only for the pre-rotation of the photosensitive member, and the control between the sheets in the continuous printing is omitted.
【００５９】（実施例３）実施例１と同様の装置及び制
御を行う。ただし帯電部材としてローラのかわりにブラ
シ形状のものを用いた。帯電ブラシとしては、一般に用
いられている繊維に導電材を分散させて抵抗調整された
ものが用いられる。(Embodiment 3) The same apparatus and control as in Embodiment 1 are performed. However, a brush-shaped charging member was used instead of the roller. As the charging brush, a commonly used fiber having a resistance adjusted by dispersing a conductive material is used.
【００６０】繊維としては、一般に知られている繊維が
使用可能であり、例えばナイロン、アクリル、レーヨ
ン、ポリカーボネート、ポリエステル等が挙げられる。As the fibers, generally known fibers can be used, and examples thereof include nylon, acrylic, rayon, polycarbonate and polyester.
【００６１】また導電材としては、これも一般に知られ
ている導電材が使用可能であり、銅、ニッケル、鉄、ア
ルミニウム、金、銀等の金属あるいは酸化鉄、酸化亜
鉛、酸化スズ、酸化アンチモン、酸化チタン等の金属酸
化物、さらにはカーボンブラック等の導電粉が挙げられ
る。なおこれら導電粉は必要に応じ疎水化、抵抗調整の
目的で表面処理が施されていてもよい。使用に際して
は、繊維との分散性や生産性を考慮して選択して用い
る。As the conductive material, a generally known conductive material can also be used. Metals such as copper, nickel, iron, aluminum, gold and silver or iron oxide, zinc oxide, tin oxide and antimony oxide can be used. , Metal oxides such as titanium oxide, and conductive powder such as carbon black. If necessary, these conductive powders may be surface-treated for the purpose of making them hydrophobic and adjusting their resistance. At the time of use, it is selected and used in consideration of dispersibility with fibers and productivity.
【００６２】また本発明に用いられる帯電ブラシの形状
としては帯電特性や耐久性等の点から繊維の太さが１デ
ニール（１．１×１０-7ｋｇ／ｍ）〜２０デニール
（２．２×１０-6ｋｇ／ｍ）、ブラシの繊維の長さは１
〜１５ｍｍ、ブラシ密度は１平方メーター当たり１．５
５×１０7 フィラメント〜４．６５×１０8 フィラメン
ト（１平方インチ当たり１万〜３０万フィラメント）の
ものが用いられる。本実施例の帯電ブラシは、導電性レ
ーヨン繊維をパイル地にしたテープを金属製の支持台に
はりつけたものである。ブラシ密度は１フィラメント当
たり６デニール（６．７×１０-7ｋｇ／ｍ）であり、１
平方メーター当たり１．５５×１０8 フィラメント（１
平方インチ当たり１０万フィラメント）であり、ブラシ
の抵抗値は１×１０5 Ωである（なお測定方法は金属製
の直径φ３０のドラムにニップ幅３ｍｍで当接させ、１
００Ｖの電圧を印加したときに流れる電流値から求め
た）。The shape of the charging brush used in the present invention has a fiber thickness of 1 denier (1.1 × 10 −7 kg / m) to 20 denier (2.2) in view of charging characteristics and durability. × 10 -6 kg / m), the fiber length of the brush is 1
~ 15mm, brush density 1.5 per square meter
The filaments used are 5 × 10 7 filaments to 4.65 × 10 8 filaments (10,000 to 300,000 filaments per square inch). In the charging brush of this embodiment, a tape made of a conductive rayon fiber as a pile material is attached to a metal support. The brush density is 6 denier per filament (6.7 × 10 -7 kg / m), and
1.55 x 10 8 filaments per square meter (1
It is 100,000 filaments per square inch, and the resistance value of the brush is 1 × 10 5 Ω (measurement method is as follows: a metal drum having a diameter of φ30 is brought into contact with a nip width of 3 mm to
It was determined from the value of the current flowing when a voltage of 00V was applied).
【００６３】また、表１に示すようにＶｄと現像バイア
スの制御値も設定を変えた。Further, as shown in Table 1, the control values of Vd and developing bias were also changed.
【００６４】この実施例においても、耐久の全期間中に
おいて良好な画像が維持された。Also in this example, a good image was maintained during the entire durability period.
【００６５】（実施例４）実施例１と同様な装置を用い
る。ただし帯電方法としてＤＣ成分にＡＣ成分を重畳さ
せた。ＤＣ成分は−７５０Ｖ、ＡＣ成分は周波数１ＫＨ
ｚ、１．２ｍＡの定電流で制御し、ＤＣ成分に対して本
発明に基づく補正制御を行った。これらの結果も表１に
示す。(Embodiment 4) An apparatus similar to that of Embodiment 1 is used. However, as a charging method, the AC component was superimposed on the DC component. DC component is -750V, AC component is frequency 1KH
The constant current of z and 1.2 mA was used for control, and the DC component was subjected to correction control based on the present invention. These results are also shown in Table 1.
【００６６】[0066]
【発明の効果】以上のように本発明によれば、像担持体
としての被帯電体の帯電処理を接触帯電手段を用いて行
う画像形成装置、更にはその帯電処理した被帯電体面に
画像情報を含んだ光像を照射する工程を含む作像プロセ
スを適用して画像形成を実行する画像形成装置につい
て、耐久による被帯電体の膜厚変化にかかわらずカブリ
の発生がなく常に充分な画像濃度と画質を維持させるこ
とができる。As described above, according to the present invention, an image forming apparatus for charging a charged body as an image carrier by using a contact charging means, and further, image information on the charged body surface An image forming apparatus that performs image formation by applying an image forming process that includes a step of irradiating a light image containing And the image quality can be maintained.
【図１】本発明の実施例１の画像形成装置の概略構成図FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment of the present invention.
【図２】上記画像形成装置の動作シーケンス図FIG. 2 is an operation sequence diagram of the image forming apparatus.
【図３】帯電能膜厚依存性を示すグラフFIG. 3 is a graph showing chargeability film thickness dependence.
【図４】本発明の実施例１の電位制御を行うための直流
電流値を示すグラフFIG. 4 is a graph showing a DC current value for performing potential control according to the first embodiment of the present invention.
【図５】本発明の実施例１の耐久枚数と膜厚の推移を示
すグラフFIG. 5 is a graph showing changes in the number of durable sheets and the film thickness in Example 1 of the present invention.
【図６】本発明の実施例１の電位制御を示すグラフFIG. 6 is a graph showing potential control of Example 1 of the present invention.
１…像担持体 ２…帯電部材 ３…電源 １０…露光手段 １１…現像手段 １２…転写手段 １３…クリーニング手段 １４…転写材 １５…除電露光装置 DESCRIPTION OF SYMBOLS 1 ... Image carrier 2 ... Charging member 3 ... Power supply 10 ... Exposure means 11 ... Developing means 12 ... Transfer means 13 ... Cleaning means 14 ... Transfer material 15 ... Eliminating exposure apparatus
Claims (1)
して該感光体を帯電させる帯電工程、該感光体の画像露
光部を現像剤にて可視化する現像工程を有する画像形成
方法において、 該帯電部材が感光体の非画像形成領域に対応している時
に該帯電部材を直流定電圧制御し、その時の感光体膜厚
に応じた直流電流量を検知し、該帯電部材が感光体の画
像形成領域に対応している時は上記検知した直流電流量
に応じた直流電圧で該帯電部材を直流定電圧制御して感
光体の膜厚減少に伴って表面電位を徐々に下げていくと
共に、現像剤供給体への印加電圧も下げていくように制
御する、ことを特徴とする画像形成方法。1. An image forming method comprising at least a charging step of directly contacting a charging member with a photosensitive member to charge the photosensitive member, and a developing step of visualizing an image-exposed portion of the photosensitive member with a developer, When the member corresponds to the non-image forming area of the photoconductor, the charging member is subjected to DC constant voltage control, and the amount of DC current according to the thickness of the photoconductor at that time is detected. In the case of the above, the constant voltage of the charging member is controlled by a direct current voltage according to the detected direct current amount to gradually decrease the surface potential as the film thickness of the photoconductor is reduced, and the developer is supplied. An image forming method characterized by controlling so that the applied voltage to the body is also lowered.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6289899A JPH08146677A (en) | 1994-11-24 | 1994-11-24 | Image forming method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6289899A JPH08146677A (en) | 1994-11-24 | 1994-11-24 | Image forming method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08146677A true JPH08146677A (en) | 1996-06-07 |
Family
ID=17749217
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6289899A Pending JPH08146677A (en) | 1994-11-24 | 1994-11-24 | Image forming method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08146677A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006106692A (en) * | 2004-09-10 | 2006-04-20 | Canon Inc | Image forming apparatus, cartridge, and storage medium |
| JP2015111215A (en) * | 2013-12-06 | 2015-06-18 | 三星電子株式会社Ｓａｍｓｕｎｇ Ｅｌｅｃｔｒｏｎｉｃｓ Ｃｏ．，Ｌｔｄ． | Image forming apparatus |
| US9671712B2 (en) | 2015-08-25 | 2017-06-06 | Canon Kabushiki Kaisha | Image forming apparatus |
-
1994
- 1994-11-24 JP JP6289899A patent/JPH08146677A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006106692A (en) * | 2004-09-10 | 2006-04-20 | Canon Inc | Image forming apparatus, cartridge, and storage medium |
| US7430378B2 (en) | 2004-09-10 | 2008-09-30 | Canon Kabushiki Kaisha | Image forming apparatus setting an image forming condition based on characteristics of a cartridge, cartridge used in the image forming apparatus, and storage medium mounted on the cartridge |
| JP2015111215A (en) * | 2013-12-06 | 2015-06-18 | 三星電子株式会社Ｓａｍｓｕｎｇ Ｅｌｅｃｔｒｏｎｉｃｓ Ｃｏ．，Ｌｔｄ． | Image forming apparatus |
| US9671712B2 (en) | 2015-08-25 | 2017-06-06 | Canon Kabushiki Kaisha | Image forming apparatus |
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