JPH0844155A - Image forming device - Google Patents

Image forming device

Info

Publication number
JPH0844155A
JPH0844155A JP6174092A JP17409294A JPH0844155A JP H0844155 A JPH0844155 A JP H0844155A JP 6174092 A JP6174092 A JP 6174092A JP 17409294 A JP17409294 A JP 17409294A JP H0844155 A JPH0844155 A JP H0844155A
Authority
JP
Japan
Prior art keywords
image
transfer
charging
area
transfer material
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.)
Withdrawn
Application number
JP6174092A
Other languages
Japanese (ja)
Inventor
Shigeo Kimura
木村　　茂雄
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Priority to JP6174092A priority Critical patent/JPH0844155A/en
Publication of JPH0844155A publication Critical patent/JPH0844155A/en
Withdrawn legal-status Critical Current

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  • Discharging, Photosensitive Material Shape In Electrophotography (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
  • Control Or Security For Electrophotography (AREA)

Abstract

PURPOSE:To make a boundary between the image area and the blank area of a transfer material sharp by previously imparting the same specified potential to a 1st area and a 2nd area on an image carrier corresponding to the blank area by an electrifying member. CONSTITUTION:Transfer bias impressed on a transfer roller 108A is -4kV when the transfer material P exists at a transfer position, and +2kV is impressed as cleaning bias in order to transfer toner from the roller 108A to a photoreceptor 102 while the transfer material P does not exist at the transfer position. The center of electrifying bias to form the blank area on the trailing edge side of the transfer material P and the center of the electrifying bias to prevent the occurrence of memory in the case of impressing the cleaning bias on the roller 108A are the same -300V. Therefore, in the area on the image carrier 102 where the toner is removed from the roller 108A and the area of the image carrier 102 corresponding to the blank area, the center of bias previously impressed on the electrifying member 103 while passing a primary electrifying position is -300V and the center of bias need not be switched.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、複写機レーザビームプ
リンタ等の画像形成装置に係り、詳しくは、感光体や誘
電体のような像担持体上に形成したトナー像を転写材に
転写する方式の画像形成装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a laser beam printer for a copying machine, and more specifically, it transfers a toner image formed on an image carrier such as a photoconductor or a dielectric to a transfer material. System image forming apparatus.

【０００２】[0002]

【背景技術】複写機、レーザビームプリンタ等の画像形
成装置において、転写部に給送され、像担持体表面に密
着されて画像転写を受けた転写材は、転写部を通過して
像担持体表面かに順次に分離されて画像定着手段へ搬送
されていくが、 （１）例えば、定着ローラ等の定着手段を用いた場合、
転写材先端部分が、定着ローラから容易に分離するよう
にするための効果的手段の１つとして、転写材先端部の
例えば５ｍｍ幅程度の面領域を非画像領域（余白部）に
する。すなわち、転写材先端部の上述の非画像領域に対
応する像担持体部分には、可転写画像（トナー像）を形
成させない処理構成とすることが挙げられる。2. Description of the Related Art In an image forming apparatus such as a copying machine or a laser beam printer, a transfer material that is fed to a transfer unit and comes into close contact with the surface of an image carrier to receive an image is passed through the transfer unit and passes through the image carrier. The surface is sequentially separated and conveyed to the image fixing unit. (1) For example, when a fixing unit such as a fixing roller is used,
As one of effective means for easily separating the leading edge of the transfer material from the fixing roller, the surface area of the leading edge of the transfer material, for example, having a width of about 5 mm is set as a non-image area (margin portion). That is, it is possible to adopt a processing configuration in which the transferable image (toner image) is not formed on the image carrier portion corresponding to the above-mentioned non-image area of the transfer material front end portion.

【０００３】（２）転写手段として転写ローラ等の転写
材の裏側に接触する接触転写手段を採択している場合、
転写材面の後端まで画像を形成させると、像担持体面の
現像剤（トナー）が飛散するため転写ローラが現像剤汚
れしやすい。転写ローラの現像剤汚れは転写剤の裏汚れ
等のトラブルを発生させることになるので、転写ローラ
をクリーニングするための複雑な手段の付加が必要とな
ってくる。(2) When the contact transfer means that contacts the back side of the transfer material such as a transfer roller is adopted as the transfer means,
When an image is formed up to the rear end of the transfer material surface, the developer (toner) on the surface of the image carrier scatters, so that the transfer roller is easily soiled with the developer. Since the developer stain on the transfer roller causes troubles such as stain on the back side of the transfer agent, it is necessary to add a complicated means for cleaning the transfer roller.

【０００４】転写ローラ現像剤汚れを防止もしくは低減
するための効果的手段の１つとして、転写材後端部の例
えば５ｍｍ幅程度の面領域を非画像領域（余白部）にす
る。すなわち、転写材後端の上述の非画像領域が対応す
る像担持体部分には可転写画像（トナー像）を形成させ
ない処置構成とすることが挙げられる。As one of effective means for preventing or reducing the contamination of the transfer roller developer, the surface area of the rear end portion of the transfer material, for example, having a width of about 5 mm is made a non-image area (margin area). That is, it is possible to adopt a treatment configuration in which a transferable image (toner image) is not formed on the image carrier portion corresponding to the above-mentioned non-image area at the rear end of the transfer material.

【０００５】（３）また、原稿を縮小して、画像形成す
るとき等は、転写材の先端部から後端部へ至るまでの任
意の位置に任意幅をもって非画像領域部（マスキング
部）を形成したい場合もある。(3) When a document is reduced to form an image, a non-image area portion (masking portion) having an arbitrary width is provided at an arbitrary position from the leading edge to the trailing edge of the transfer material. You may want to form it.

【０００６】上述（１）のように転写材の像担持体面か
らの分離を容易・スムーズにする、（２）のように転写
ローラの現像剤汚れを防止・低減する、（３）のように
マスキング処置をする等のために転写材面の先端部、後
端部、任意中間部を非画像領域化する手段として、従来
は、例えば電子写真装置の場合は帯電処置した像担持体
たる感光体面の所要領域を露光処置して現像剤が付着し
ない非画像領域（非帯電領域）にする方式がとられてい
た。As described in (1) above, the separation of the transfer material from the surface of the image bearing member is facilitated and smoothed, as in (2), the contamination of the transfer roller with the developer is prevented and reduced, and as in (3). In the past, for example, in the case of an electrophotographic apparatus, as a means for making the front end portion, rear end portion, and arbitrary intermediate portion of the transfer material surface into a non-image area for masking treatment, for example, in the case of an electrophotographic apparatus, a photoreceptor surface as an image bearing member has been charged. The required area is subjected to an exposure treatment to form a non-image area (non-charged area) where the developer does not adhere.

【０００７】しかし、露光処理による方式は、装置が複
雑かつ大型になる欠点を有していた。However, the exposure processing method has a drawback that the apparatus becomes complicated and large in size.

【０００８】これを改善する方式として、一次帯電器と
しての帯電ローラ等の接触帯電手段の帯電幅が狭いこと
を積極的に利用して、転写材にブランク領域を形成する
ために接触帯電部材に対する印加電圧をシフト制御する
方式が本出願人によって特開平２−３０１７７８号公報
に提案されている。As a method of improving this, a narrow charging width of a contact charging means such as a charging roller as a primary charging device is positively utilized, and a contact charging member is formed to form a blank area on a transfer material. A method of controlling the applied voltage shift has been proposed by the present applicant in Japanese Patent Laid-Open No. 2-301778.

【０００９】しかしながら、接触帯電部材に対する印加
電圧をシフト制御する方式においても、シフト制御の切
換え時間Ｔが長い場合、 （１）画像先端部及び後端部がシャープにならない。す
なわち、画像濃度が徐々に変化した画像先後端になって
しまう。 （２）また、高濃度部と中間調部で、画像先端部及び後
端部がズレてしまう。すなわち、画像先端部において、
シフト制御したときの像担持体電位は、図３７のＤのよ
うになるが、ある程度露光を受ける中間調部は、Ｈのよ
うになる。However, even in the method of controlling the shift of the voltage applied to the contact charging member, if the shift control switching time T is long, (1) the leading edge portion and the trailing edge portion of the image are not sharp. That is, the leading and trailing edges of the image are those where the image density has gradually changed. (2) Further, the leading edge portion and the trailing edge portion of the image are deviated between the high density portion and the halftone portion. That is, at the image tip,
The image carrier potential when the shift control is performed is as shown by D in FIG. 37, but the halftone portion which is exposed to a certain extent becomes as shown by H.

【００１０】したがって、図３に示すようにほとんど露
光されない高濃度部の現像開始部（Ａ）とある程度露光
される中間調の原稿開始部（Ｂ）に時間差が生じるため
に、画像開始部が画像濃度によって異なるという現象が
生じる。後端部も同様である。Therefore, as shown in FIG. 3, there is a time difference between the developing start portion (A) of the high density portion which is hardly exposed and the original start portion (B) of the halftone which is exposed to some extent, so that the image start portion is an image. The phenomenon that it varies depending on the concentration occurs. The same applies to the rear end.

【００１１】なお、ここで切換え時間Ｔとは、シフト前
電圧から所定のシフト後電圧にシフトさせたとき、シフ
ト電圧分の９０％シフトするのに要する時間とする。ま
た、印加電圧が振動電圧の場合、シフト制御とは、該振
動電圧の中心のシフト制御である。The switching time T is the time required to shift 90% of the shift voltage when the pre-shift voltage is shifted to the predetermined post-shift voltage. When the applied voltage is an oscillating voltage, shift control is shift control of the center of the oscillating voltage.

【００１２】上記、（１）、（２）のような画像は、プ
ロセススピードが速いほど、また、切換え時間Ｔが長い
ほど悪くなる。The images of the above (1) and (2) become worse as the process speed becomes faster and the switching time T becomes longer.

【００１３】一方、シフト制御の切換え時間を極めて短
くすることは、 （１）切換え時に、オーバーシュートが生じやすい。 （２）ノイズが生じ故障の原因となる。 等の問題が生じ、これら（１）、（２）の対策が電源に
必要となるために、装置が複雑かつ大型化してしまう。 （３）また、急激な電圧変化はラッシュ電流が生じ接触
帯電部材や像担持体にダメージを与え、耐久寿命が短く
なる。 などの問題が生じるので必要以上に切換え時間を短くす
るべきではない。On the other hand, if the shift control switching time is made extremely short, (1) overshoot is likely to occur at the time of switching. (2) Noise is generated and causes a failure. As a result, problems such as (1) and (2) are required for the power supply, so that the device becomes complicated and large. (3) In addition, a rapid voltage change causes a rush current to damage the contact charging member and the image carrier, resulting in a shorter life. Since such problems occur, the switching time should not be shortened more than necessary.

【００１４】一方、転写ローラに付着したトナーを像担
持体である感光体に戻すために転写ローラにトナー極性
と同極性（一次帯電器の帯電極性と逆極性）の電圧を印
加すると感光体にメモリが生じる問題があった。このメ
モリによって次に画像形成を行うときに電位が低くなる
ので画像ボケを生じることがあった。このメモリの発生
を防止するために転写ローラのトナーが戻される感光体
のクリーニング領域をあらかじめ一次帯電器で帯電する
ことが知られている。しかしながら、既述したように転
写材の端部にブランク領域を形成するためにブランク領
域に対応する感光体の領域をあらかじめ一次帯電器で帯
電しないようにすると、感光体のクリーニング領域と、
ブランク領域に対応する感光体の領域と、で異なる電位
となるために一次帯電器に印加する電圧の切換え制御が
複雑になってしまう。On the other hand, in order to return the toner adhering to the transfer roller to the photosensitive member which is the image carrier, a voltage having the same polarity as the toner polarity (the opposite polarity to the charging polarity of the primary charger) is applied to the transfer roller. There was a problem with memory. Due to this memory, the potential becomes low when the image is formed next time, so that image blur may occur. In order to prevent the occurrence of this memory, it is known that the cleaning area of the photoconductor on which the toner of the transfer roller is returned is charged in advance by the primary charger. However, as described above, if the area of the photoconductor corresponding to the blank area is not charged in advance by the primary charger to form the blank area at the end of the transfer material, the cleaning area of the photoconductor,
Since the potential of the photoconductor region corresponding to the blank region is different from that of the photoconductor region, control of switching the voltage applied to the primary charger becomes complicated.

【００１５】[0015]

【発明の目的】本発明の目的は、転写材上の画像領域と
ブランク領域との境界がシャープとなる画像形成装置を
提供することである。SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus having a sharp boundary between an image area and a blank area on a transfer material.

【００１６】本発明の他の目的は、画像の高濃度部の端
部と画像の中間濃度部の端部とのズレを低減させること
ができる画像形成装置を提供することである。Another object of the present invention is to provide an image forming apparatus capable of reducing the deviation between the edge of the high density portion of the image and the edge of the intermediate density portion of the image.

【００１７】本発明の他の目的は、転写メモリの発生を
防止した画像形成装置を提供することである。Another object of the present invention is to provide an image forming apparatus which prevents the occurrence of a transfer memory.

【００１８】本発明の他の目的は、帯電部材に印加する
電位の切換えにより転写材上にブランク領域を形成する
画像形成装置を提供することである。Another object of the present invention is to provide an image forming apparatus for forming a blank area on a transfer material by switching the potential applied to the charging member.

【００１９】[0019]

【発明の構成】上記目的を達成するために、本発明は画
像を担持する像担持体と、上記像担持体を帯電する帯電
部材であって、この帯電部材による帯電を用いて上記像
担持体にはトナー像が形成される帯電部材と、上記トナ
ー像を上記像担持体から転写材へ転写する転写手段であ
って、この転写手段は、転写材の、上記像担持体の側と
は、逆側に接する転写部材を有し、転写位置に転写材な
しで、上記像担持体の第１領域が通過する間、上記転写
部材には上記帯電部材の帯電極性と逆極性の電圧が印加
される転写手段と、上記像担持体の移動方向において転
写材の端部を含むブランク領域を形成するために上記帯
電材に印加する電位を切り換え制御する制御手段と、を
する画像形成装置において、上記第１領域と、上記ブラ
ンク領域に対応する上記像担持体の第２領域と、はあら
かじめ上記帯電部材によって同じ所定電位が付与される
ことを特徴とするものである。SUMMARY OF THE INVENTION To achieve the above object, the present invention comprises an image bearing member carrying an image and a charging member for charging the image bearing member, wherein the image bearing member is charged by charging by the charging member. Is a charging member on which a toner image is formed, and transfer means for transferring the toner image from the image carrier to a transfer material. The transfer means is a transfer material on the image carrier side. A voltage having a polarity opposite to the charging polarity of the charging member is applied to the transfer member while the transfer member is in contact with the opposite side and the first region of the image carrier passes without the transfer material at the transfer position. And a control means for switching and controlling the electric potential applied to the charging material to form a blank area including the end portion of the transfer material in the moving direction of the image carrier. It corresponds to the first area and the blank area. A second region of said image bearing member, is characterized in that the same predetermined potential is applied in advance by the charging member.

【００２０】[0020]

【実施例】以下、本発明の実施例を図面に基づいて説明
する。Embodiments of the present invention will be described below with reference to the drawings.

【００２１】図１に、本発明に係る画像形成装置の構成
の概略を示す。FIG. 1 shows a schematic structure of an image forming apparatus according to the present invention.

【００２２】同図において、１０１は装置本体、１０２
は像担持体としてのドラム型の電子写真感光体（以下単
に「感光体」という。）であり、支軸１０２ａを中心に
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る。本実施例では、感光体は負帯電
極性の有機光導電層を用いている。In the figure, 101 is the main body of the apparatus, and 102
Is a drum type electrophotographic photosensitive member (hereinafter simply referred to as “photosensitive member”) as an image bearing member, which is rotationally driven around the support shaft 102a in a clockwise direction indicated by an arrow at a predetermined peripheral speed (process speed). It In this embodiment, the photoconductor uses an organic photoconductive layer having a negative charging polarity.

【００２３】１０３は感光体１０２の周面をマイナスに
均一帯電する手段（一次帯電器）としての接触帯電部材
である。本例の接触帯電部材１０３は導電性ゴム等から
なるローラタイプのもので、感光体１０２表面に対して
所定の一定圧で押圧接触させ従動回転するようにしてい
る。１０４は接触帯電部材１０３に対する電圧印加源で
あり、本実施例では交流電圧と、帯電電位を規定する直
流電圧を重畳した振動電圧を印加しており、具体的には
ピーク間電圧１８００Ｖの交流電圧ＡＣと、−６００Ｖ
の直流電圧ＤＣを重畳した振動電圧（ＡＣ＋ＤＣ）を印
加している。直流電圧ＤＣが振動電圧の中心となる。感
光体１０２はこの電圧を印加した帯電部材１０３の接触
により回転に伴いその周面が所定の電位に順次に均一に
帯電し処理される。上記振動電圧のピーク間電圧は、感
光体の斑点状帯電むらを防止するために、感光体の帯電
開始電圧の２倍以上であることが望ましい。上記帯電開
始電圧は、感光体と接触帯電部材との間に仮にＤＣ電圧
を印加した場合、感光体の帯電が開始するときの印加Ｄ
Ｃ電圧である。振動電圧の波形は、正弦波、三角波、矩
形波等用いることができるが、振動電圧は直流電源のオ
ンオフを繰り返して形成される、ＡＣ電圧とＤＣ電圧と
の重畳電圧の形状でも良い。Reference numeral 103 denotes a contact charging member as a means (primary charger) for uniformly negatively charging the peripheral surface of the photoconductor 102. The contact charging member 103 of this example is of a roller type made of conductive rubber or the like, and is pressed and brought into contact with the surface of the photoconductor 102 at a predetermined constant pressure so as to be driven to rotate. Reference numeral 104 denotes a voltage application source for the contact charging member 103. In the present embodiment, an oscillating voltage obtained by superimposing an AC voltage and a DC voltage defining the charging potential is applied, and specifically, an AC voltage having a peak-to-peak voltage of 1800V. AC and -600V
The oscillating voltage (AC + DC) superposed with the DC voltage DC is applied. The DC voltage DC becomes the center of the oscillating voltage. Due to the contact of the charging member 103 to which the voltage is applied, the photosensitive member 102 is sequentially and uniformly charged to a predetermined potential on its peripheral surface as it rotates and processed. The peak-to-peak voltage of the oscillating voltage is preferably at least twice the charging start voltage of the photoconductor in order to prevent uneven charging of the photoconductor. The charging start voltage is applied D when the charging of the photoconductor starts when a DC voltage is applied between the photoconductor and the contact charging member.
C voltage. The waveform of the oscillating voltage may be a sine wave, a triangular wave, a rectangular wave, or the like, but the oscillating voltage may be in the form of a superimposed voltage of the AC voltage and the DC voltage, which is formed by repeatedly turning on and off the DC power supply.

【００２４】帯電部材１０３により均一帯電処理された
感光体１０２表面は、次いで露光部１０５において後述
するように原稿画像のスリット露光１０６を順次に受け
る。これにより感光体１０２面に露光光像パターンに対
応した静電潜像が順次に形成させていく。その静電潜像
は次いで現像装置１０７により正帯電極性のトナーで順
次にトナー像として顕像（現像）され、転写用帯電器
（転写用ローラ）１０８Ａと感光体１０２とのニップ部
である転写部へ至る。The surface of the photosensitive member 102, which has been uniformly charged by the charging member 103, is then sequentially subjected to slit exposure 106 of the original image in the exposure section 105 as described later. Thereby, electrostatic latent images corresponding to the exposure light image pattern are sequentially formed on the surface of the photoconductor 102. The electrostatic latent image is subsequently visualized (developed) as a toner image with toner of positively charged polarity in order by the developing device 107, and the transfer is performed at the nip portion between the transfer charger (transfer roller) 108A and the photoconductor 102. To the department.

【００２５】一方、給紙部にセットした用紙カセット１
１５内の転写材Ｐが給紙ローラ１１６と分離部材との協
働で１枚宛装置本体１０１内へ搬送され、ガイド１１
７、搬送ローラ対１１８、ガイド１１９、タイミングロ
ーラ対（レジストローラ対）１２０、ガイド１２１を経
由して、負の電圧が印加された転写用帯電器１０８Ａと
感光体１０２との対向部である転写部に感光体１０２の
回転と同期取りされて給送され、この転写材Ｐの表面
に、感光体１０２表面のトナー像が順次に転写されてい
く。On the other hand, the paper cassette 1 set in the paper feeding section
The transfer material P in 15 is conveyed into the apparatus main body 101 for one sheet by the cooperation of the paper feed roller 116 and the separation member, and the guide 11
7, a transfer roller pair 118, a guide 119, a timing roller pair (registration roller pair) 120, and a guide 121, which is a transfer portion which is a facing portion of the transfer charger 108A and the photoconductor 102 to which a negative voltage is applied. The toner image on the surface of the photoconductor 102 is sequentially transferred to the surface of the transfer material P while being synchronized with the rotation of the photoconductor 102.

【００２６】転写部を通過した転写材Ｐは感光体１０２
表面から分離され、搬送装置１０９により定着装置１１
２へ導入されて画像定着を受け、搬出口１１３から排紙
トレイ１１４へ出力される。The transfer material P that has passed through the transfer portion is the photosensitive member 102.
The fixing device 11 is separated from the surface and is fixed by the conveying device 109.
Then, the image is fixed to the sheet, and the image is fixed, and the sheet is output from the carry-out port 113 to the sheet discharge tray 114.

【００２７】転写材分離後の感光体１０２表面はクリー
ニング装置１１０で転写残りトナー等の付着汚染物の除
去、全面露光器１１１等の除電器による残留電荷消去を
受けて洗浄面化され、繰り返して画像形成の実行に供さ
れる。After the transfer material is separated, the surface of the photosensitive member 102 is cleaned by a cleaning device 110 to remove adhered contaminants such as transfer residual toner and erase residual charges by a static eliminator such as a full-face exposure device 111, and is repeatedly cleaned. It is used to execute image formation.

【００２８】複写開始信号により原稿台ガラス１５１
は、図１の左右方向に往復移動するように駆動され、ス
リット露光部１０５を通過していく過程で原稿台ガラス
１５１上のセット原稿Ｄの下向き画像面が照明ランプ１
３０により一辺側から他辺側に順次に照明され、その照
明光の原稿面反射光が短焦点レンズアレイ１３１によ
り、前記帯電ローラ３による帯電処理後の感光ドラム１
０２表面に結像露光１０５されることで、感光体１０２
表面に原稿画像に対応した静電潜像が形成される。この
形成潜像は次いで現像装置１０７１０７によりトナー現
像される。The original platen glass 151 according to a copy start signal
Is driven so as to reciprocate in the left-right direction in FIG. 1, and in the process of passing through the slit exposure section 105, the downward image surface of the set original D on the original table glass 151 is illuminated by the illumination lamp 1.
30 is sequentially illuminated from one side to the other side, and the reflected light from the original surface of the illumination light is irradiated by the short focus lens array 131 by the photosensitive roller 1 after the charging process by the charging roller 3.
02 image formation exposure 105 on the surface of the photoconductor 102
An electrostatic latent image corresponding to the original image is formed on the surface. The formed latent image is then toner-developed by the developing device 107107.

【００２９】本実施例の画像形成装置は、プロセススピ
ードＶPSが１００ｍｍ／ｓｅｃであるが、振動電圧の中
心電圧（直流電圧ＤＣ分）を、非画像領域形成時には０
Ｖ、画像形成時には−６００Ｖに制御回路１４０によっ
て制御し、これらの印加電圧の切換えを転写材Ｐの搬送
に同期させて、切換え時間Ｔ＝５０ｍｓｅｃで行うこと
で、転写材先端部５ｍｍ幅、及び転写材後端部５ｍｍ幅
の非画像領域（ブランク領域）を形成させている。先端
の非画像領域を形成することで転写装置１１２の定着ロ
ーラ通過後の転写材Ｐの分離を容易にでき、また、後端
の非画像領域を形成することで転写材後端部転写時の現
像剤飛散による転写ローラ１０８Ａの汚れを防ぐことが
できる。なおこの非画像形成領域とは、原稿の任意の画
像情報に対してトナー像が形成されない領域である。In the image forming apparatus of this embodiment, the process speed V PS is 100 mm / sec, but the center voltage of the oscillating voltage (DC voltage component) is 0 when the non-image area is formed.
V, at the time of image formation, the control circuit 140 controls the voltage to be −600 V, and switching of these applied voltages is performed in synchronization with the transfer of the transfer material P at a switching time T = 50 msec. A non-image area (blank area) having a width of 5 mm at the rear end of the transfer material is formed. By forming the non-image area at the front end, the transfer material P can be easily separated after passing through the fixing roller of the transfer device 112, and by forming the non-image area at the rear end, the rear end portion of the transfer material is transferred. It is possible to prevent the transfer roller 108A from being contaminated due to scattering of the developer. The non-image forming area is an area in which a toner image is not formed with respect to arbitrary image information of a document.

【００３０】電圧制御シーケンスをさらに詳しく説明す
ると、給紙部から転写材Ｐが搬送されるのを給紙センサ
（フォトセンサ）Ｓ１が検知し、感光体１０２が回転駆
動を始め、原稿Ｄも走査される。接触帯電部材１０３に
は交流電圧ＡＣ（ピーク間電圧１８００Ｖ）のみが、す
なわち、中心電圧０Ｖが印加され、その後タイミングロ
ーラ対１２０と同期し転写材Ｐの先端部５ｍｍ以降から
画像形成するタイミングで中心電圧を０Ｖから−６００
Ｖまで５０ｍｓｅｃでシフトさせ、感光体１０２を帯電
し始める。The voltage control sequence will be described in more detail. The feeding sensor (photosensor) S1 detects that the transfer material P is conveyed from the feeding portion, the photosensitive member 102 starts to rotate, and the original D is also scanned. To be done. Only the AC voltage AC (peak-to-peak voltage of 1800V), that is, the center voltage of 0V is applied to the contact charging member 103, and then the center is synchronized with the timing roller pair 120 and at the timing of forming an image from the tip 5 mm or later of the transfer material P. Voltage from 0V to -600
The voltage is shifted to V in 50 msec and the photoconductor 102 starts to be charged.

【００３１】帯電部材１０３に対する印加電圧を、直流
電圧を０Ｖにし、交流電圧ＡＣのみを印加したときは感
光体１０２表面は除電され表面電位０Ｖとなり、トナー
像は形成されない。帯電部材に直流電圧ＤＣを加えると
感光体１０２表面の帯電が開始される。When the DC voltage is 0 V and only the AC voltage AC is applied to the charging member 103, the surface of the photosensitive member 102 is neutralized and the surface potential becomes 0 V, and no toner image is formed. When a DC voltage DC is applied to the charging member, the surface of the photoconductor 102 starts to be charged.

【００３２】つまり転写材Ｐが対応する感光体表面領域
の先端部５ｍｍだけ内側以降から接触帯電部材１０３に
よる感光体１０２面の帯電処理が開始されるように接触
帯電部材１０３に対する電圧印加を制御するシーケンス
にしてあり、これにより転写部を通過して像転写を受け
感光体１０２表面に密着している転写材Ｐはその先端部
５ｍｍ幅の領域はトナー像のない非画像領域部分（余白
部）となる。That is, the voltage application to the contact charging member 103 is controlled so that the charging process of the surface of the photosensitive member 102 by the contact charging member 103 is started from the inside of the tip portion 5 mm of the corresponding surface area of the photosensitive member to which the transfer material P is located. The transfer material P, which is arranged in a sequence and which is transferred to the surface of the photoconductor 102 by the image transfer and is in close contact with the surface of the photoconductor 102, has a non-image area portion (margin portion) having no toner image in the area of the tip portion of 5 mm width. Becomes

【００３３】ここで、プロセススピードＶPS＝１００ｍ
ｍ／ｓｅｃに対して、シフト制御の切換え時間Ｔを５０
ｍｓｅｃにすることで、画像先端部が、濃度がだんだん
濃くなるようなぼやけた先端になることなく、シャープ
で、かつ、ベタ黒やライン部のような高濃度部（ＶD
部）と中間調部（ＶH 部）のズレ量も、１〜２ｍｍと問
題ない程度の画像が得られる。Here, the process speed V PS = 100 m
The shift control switching time T is set to 50 with respect to m / sec.
By setting it to msec, the leading edge of the image does not become a blurry leading edge where the density becomes gradually darker, and is sharp, and the high density portion (V D
The amount of misalignment between the image portion) and the halftone portion ( VH portion) is 1 to 2 mm, and an image with no problem can be obtained.

【００３４】同様に転写材後端をセンサＳ１で検知し、
転写材後端部５ｍｍから非画像領域を形成するタイミン
グで中心電圧を−６００Ｖから０Ｖに切換え時間Ｔ＝５
ｍｓｅｃでシフトさせることで、シャープな画像後端部
を形成する。Similarly, the rear end of the transfer material is detected by the sensor S1,
The central voltage is changed from -600V to 0V at the timing of forming the non-image area from the rear end portion of the transfer material 5 mm. Time T = 5
By shifting in msec, a sharp image trailing edge portion is formed.

【００３５】本出願人らの実験によると、プロセススピ
ードＶSP＝１００ｍｍ／ｓｅｃの画像形成装置において
は、現像のバイアス値にもよるが、通常のバイアス値で
は、シフト制御の切換え時間Ｔが１００ｍｓｅｃより大
きいと、画像先後端部に濃度の薄いぼやけた領域が形成
されてしまった。また、高濃度部と中間調部が混在した
画像を形成したときには、高濃度部の画像先後端部と、
中間濃度部の画像後端部が５ｍｍ以上ズレるために、エ
ッジが凹凸した見苦しい画像となった。According to the experiments by the applicants, in an image forming apparatus having a process speed V SP = 100 mm / sec, the shift time T of switching control is 100 msec at a normal bias value, although it depends on the bias value of development. If it is larger, a blurry region having a low density is formed at the front and rear edges of the image. Also, when forming an image in which the high density portion and the halftone portion are mixed, the image front and rear end portions of the high density portion,
Since the trailing edge of the image in the middle density portion is displaced by 5 mm or more, the image is unsightly with uneven edges.

【００３６】また、シフト制御の切換え時間Ｔを短くす
ると、画像先後端部のシャープ性は良くなり、高濃度部
と中間調濃度部のズレ量は低減するが、切換え時間Ｔが
２０ｍｓｅｃ以下では、それ以上シャープ性は良くなら
なかった。本実施例の装置において像担持体１０２及び
帯電ローラ１０３を非回転状態（停止状態）で電圧を一
瞬印加して像担持体を帯電した後、像担持体１０２を回
転させ、帯電された領域を現像する。このとき感光体移
動方向における現像幅を測定すると感光体移動方向にお
いて帯電部材による帯電開始位置から帯電終了位置まで
の距離Ｘ（図２参照）を求めることができる。本実施例
では距離Ｘは２ｍｍであり、距離Ｘを感光体が通過する
時間よりも切換え時間Ｔが短くしていってもブランク領
域と画像領域との境界のシャープ性は、変わらないこと
がわかった。When the switching time T of the shift control is shortened, the sharpness of the front and rear edges of the image is improved and the shift amount between the high density portion and the halftone density portion is reduced, but when the switching time T is 20 msec or less, Sharpness did not improve any further. In the apparatus of the present embodiment, the image carrier 102 and the charging roller 103 are non-rotated (stopped state), a voltage is momentarily applied to charge the image carrier, and then the image carrier 102 is rotated to remove the charged area. develop. At this time, by measuring the developing width in the photosensitive member moving direction, the distance X (see FIG. 2) from the charging start position to the charging end position of the charging member in the photosensitive member moving direction can be obtained. In this embodiment, the distance X is 2 mm, and it is found that the sharpness of the boundary between the blank area and the image area does not change even if the switching time T is shorter than the time required for the photoconductor to pass the distance X. It was

【００３７】また、切換え時間Ｔを短くするにつれて切
換え時の電圧オーバーショートの発生を防ぐのが困難に
なり、画像の先後端部の感光体１０２が過剰帯電し、濃
度ムラが発生してしまうことがあった。また、切換え時
間Ｔのラッシュ電流により、感光体１０２にダメージを
与えてしまうこともあった。Further, as the switching time T is shortened, it becomes difficult to prevent the occurrence of voltage over-short circuit at the time of switching, and the photoconductors 102 at the front and rear end portions of the image are excessively charged and uneven density occurs. was there. Further, the rush current during the switching time T may damage the photoconductor 102.

【００３８】上述と同様の実験をプロセススピードＶPS
＝２００ｍｍ／ｓｅｃの画像形成装置で、行ったとこ
ろ、切換え時間Ｔ＝５０ｍｓｅｃ以下で先後端に良好な
非画像領域が形成でき、また、１０ｍｓｅｃ以下ではそ
れ以上良くならなかった。An experiment similar to that described above was performed at the process speed V PS.
= 200 mm / sec, an excellent non-image region was formed at the front and rear edges when the switching time T was 50 msec or less, and it did not improve further when 10 msec or less.

【００３９】本発明者の実験の結果、距離Ｘ［ｍｍ］、
プロセススピードＶPS［ｍｍ／ｓｅｃ］、ブランク領域
を形成するために帯電部材に印加する電圧の切換え時間
Ｔ［ｓｅｃ］との間にＸ≦Ｔ・ＶPS≦１０［ｍｍ］が成
立するようにすることによって転写材上に良好なブラン
ク領域を形成することができる。なお距離Ｘは、図２に
示すように帯電部材１０３と感光体１０２とのニップの
幅Ｎと、このニップよりも感光体移動方向上流側の帯電
部材の放電幅ＣＩと、ニップよりも感光体移動方向下流
側の帯電部材の放電幅Ｃ２と、の和である。As a result of the experiment by the present inventor, the distance X [mm],
X ≦ T · V PS ≦ 10 [mm] is satisfied between the process speed V PS [mm / sec] and the switching time T [sec] of the voltage applied to the charging member to form the blank area. By doing so, a good blank area can be formed on the transfer material. The distance X is, as shown in FIG. 2, the width N of the nip between the charging member 103 and the photoconductor 102, the discharge width CI of the charging member on the upstream side of the nip in the photoconductor moving direction, and the photoconductor than the nip. It is the sum of the discharge width C2 of the charging member on the downstream side in the moving direction.

【００４０】上述の実施例では、帯電部材１０３への印
加電圧を画像形成時に−６００Ｖ非画像領域形成時には
０Ｖとし現像バイアスはシフトしないようにしたが、本
実施例は、非画像形成時に０Ｖにせず、例えば−３００
Ｖにシフトさせ、それに同期させて、現像バイアスをト
ナーが現像されないバイアス、例えば、−３５０Ｖにシ
フトさせることで、非画像領域を形成するものである。In the above-described embodiment, the voltage applied to the charging member 103 is set to -600V during image formation and 0V during non-image area formation so that the developing bias is not shifted. However, in this embodiment, the voltage may be set to 0V during non-image formation. No, for example, -300
The non-image area is formed by shifting the developing bias to V, and in synchronism therewith, shifting the developing bias to a bias at which the toner is not developed, for example, −350V.

【００４１】図４のタイミングチャートに示すように、
帯電中心電圧は転写材先端部５ｍｍから画像が形成され
るタイミングｔ1 で、−３００Ｖから−６００Ｖにシフ
トされ、現像バイアスも転写材先端部５ｍｍから画像が
形成されるタイミングｔ2 で、−３５０Ｖから、最適濃
度の画像が形成される電圧（可変）、例えば−２００Ｖ
にシフトされる。（ｔ2 −ｔ1 ）は、感光体１０２が帯
電部から現像部まで移動するのにかかる時間である。画
像後端部は同様に、逆にシフトさせることで非画像領域
部が形成される。As shown in the timing chart of FIG.
Charging center voltage at the timing t 1 an image is formed from the leading edge of the transfer material portion 5 mm, it is shifted from -300V to -600 V, in the developing time t 2 to bias even image is formed from the leading edge of the transfer material portion 5 mm, -350 V From the voltage (variable) at which an image of optimum density is formed, for example, -200V
Is shifted to. (T 2 −t 1 ) is the time required for the photoconductor 102 to move from the charging section to the developing section. Similarly, the rear end portion of the image is reversely shifted to form a non-image area portion.

【００４２】また、図４に転写材後端部にブランク領域
が形成されるように、帯電中心電圧はタイミングｔ3 で
−６００Ｖから−３００Ｖにシフトされ、上記ブランク
領域が形成されるように現像バイアスはタイミングｔ4
で−２００Ｖから−３５０Ｖにシフトされる。（ｔ4 −
ｔ3 ）は（ｔ2 −ｔ1 ）に等しい。Further, as shown in FIG. 4, the charging center voltage is shifted from -600V to -300V at timing t 3 so that a blank area is formed at the trailing end of the transfer material, and development is performed so that the blank area is formed. Bias is timing t 4
It shifts from -200V to -350V. (T 4 −
t 3) is equal to (t 2 -t 1).

【００４３】図４に示した帯電バイアス中心及び現像バ
イアス中心に加えて転写バイアス中心を加えたタイミン
グチャートを図５に示す。図５においては図４と異な
り、感光体の移動時間を省略している。即ち、図５にお
いて感光体の一次帯電位置から現像位置までの移動時間
及び感光体の現像位置から転写位置までの移動時間は省
略されている。図５においては、画像形成装置に対して
コピーボタン等により画像形成開始信号が入力された
後、転写材２枚を連続コピーするシーケンスを示す。ま
た、原稿と転写材は同じサイズであるが、原稿の画像を
縮少して転写材上に形成しているために転写材の後端側
のブランク領域は、転写材の先端側のブランク領域より
も大きくなっている。図５において図４と同様に画像形
成するために帯電バイアス中心は−６００Ｖ、現像バイ
アスは−２００Ｖ、転写材上にブランク領域を形成する
ために帯電バイアス中心は−３００Ｖ、現像バイアスは
−３５０Ｖとしている。転写ローラ１０８Ａに印加され
る転写バイアスは少なくとも転写位置に転写材があると
きに−４ｋＶであり、転写位置に転写材がない間の少な
くとも一部で転写ローラから感光体へトナーを移すため
にクリーニングバイアスとして＋２ｋＶを印加する。転
写ローラにクリーニングバイアスとして＋２ｋＶを印加
した場合、転写位置における感光体の電位が０Ｖである
と感光体にメモリが発生し易くなる。したがって、この
メモリを防止するために図５に示すように転写ローラに
クリーニングバイアスとして＋２ｋＶを印加した場合、
転写位置における感光体の電位は−３００Ｖ（帯電部材
によって感光体が帯電される電位は帯電バイアス中心と
ほぼ同じである。）となっている。したがって、感光体
がプラスに帯電されるのを防止できる。図５に示すよう
に転写材の後端側にブランク領域を形成するための帯電
バイアス中心と、転写ローラにクリーニングバイアスが
印加される場合にメモリの発生を防止する帯電バイアス
中心は同じ−３００Ｖとしている。したがって、本実施
例によれば転写ローラからトナーがクリーニングされる
像担持体の領域と、ブランク領域に対応する像担持体の
領域と、があらかじめ一次帯電位置を通過する間帯電部
材に印加されるバイアス中心は−３００Ｖでバイアス中
心を切換えなくて良い。FIG. 5 shows a timing chart in which the transfer bias center is added in addition to the charging bias center and the developing bias center shown in FIG. Unlike FIG. 4, the moving time of the photoconductor is omitted in FIG. That is, in FIG. 5, the moving time from the primary charging position of the photoconductor to the developing position and the moving time from the developing position of the photoconductor to the transfer position are omitted. FIG. 5 shows a sequence in which two transfer materials are continuously copied after an image formation start signal is input to the image forming apparatus by a copy button or the like. Although the original and the transfer material have the same size, the blank area on the trailing end side of the transfer material is smaller than the blank area on the leading end side of the transfer material because the image of the original is shrunk and formed on the transfer material. Is also getting bigger. In FIG. 5, the charging bias center is −600 V, the developing bias is −200 V for forming an image as in FIG. 4, the charging bias center is −300 V and the developing bias is −350 V for forming a blank area on the transfer material. There is. The transfer bias applied to the transfer roller 108A is −4 kV at least when the transfer material is present at the transfer position, and cleaning is performed to transfer the toner from the transfer roller to the photoconductor at least at a part while the transfer material is not present at the transfer position. +2 kV is applied as a bias. When +2 kV is applied as a cleaning bias to the transfer roller, if the potential of the photoconductor at the transfer position is 0 V, memory is likely to occur on the photoconductor. Therefore, when +2 kV is applied as a cleaning bias to the transfer roller as shown in FIG. 5 in order to prevent this memory,
The potential of the photoconductor at the transfer position is -300 V (the potential at which the photoconductor is charged by the charging member is almost the same as the center of the charging bias). Therefore, the photoconductor can be prevented from being positively charged. As shown in FIG. 5, the center of the charging bias for forming a blank area on the rear end side of the transfer material and the center of the charging bias for preventing the occurrence of memory when the cleaning bias is applied to the transfer roller are the same −300V. There is. Therefore, according to the present embodiment, the area of the image carrier on which the toner is cleaned from the transfer roller and the area of the image carrier corresponding to the blank area are applied to the charging member while passing through the primary charging position in advance. The bias center is -300 V, and it is not necessary to switch the bias center.

【００４４】なお、本実施例においても、良好な画像先
後端を形成するには、Ｘ≦Ｔ・ＶPS≦１０ｍｍの切換え
時間が必要である。Also in this embodiment, in order to form a good image front / rear edge, a switching time of X ≦ T · V PS ≦ 10 mm is required.

【００４５】本実施例では、以下の利点がある。This embodiment has the following advantages.

【００４６】（１）非画像形成時と画像形成時の帯電部
材に印加される電圧差が小さいので、切換え時のオーバ
ーショートやラッシュ電流を低減できる。(1) Since the voltage difference applied to the charging member during non-image formation and during image formation is small, over-shorting and rush current at the time of switching can be reduced.

【００４７】（２）現像バイアスを帯電バイアスに同期
させてシフトさせることによって、よりシャープな画像
先後端が転写材に形成できる。(2) By shifting the developing bias in synchronism with the charging bias, sharper image front and rear edges can be formed on the transfer material.

【００４８】（３）転写ローラ等の接触方式の転写手段
を用いる場合。(3) When using a contact type transfer means such as a transfer roller.

【００４９】転写材が転写位置に存在しないとき（紙間
など）に、トナーの帯電極性と同極性の電圧を転写部材
に印加しても、像担持体がメモリを発生するのを防ぐこ
とができる。It is possible to prevent the image carrier from generating a memory even when a voltage having the same polarity as the toner charging polarity is applied to the transfer member when the transfer material is not present at the transfer position (such as between sheets). it can.

【００５０】また、以上の実施例において転写材の先
端、または後端を含むブランク領域を形成しているが、
これに限られず以下の実施例では、図１と同様な簡易な
画像形成装置において、複雑な装置なしで任意の位置に
非画像領域を形成（マスキング処置）することを可能と
したものである。In the above embodiment, the blank area including the leading end or the trailing end of the transfer material is formed.
The present invention is not limited to this, and in the following simple image forming apparatus similar to FIG. 1, it is possible to form a non-image area (masking treatment) at an arbitrary position without a complicated apparatus.

【００５１】すなわち、原稿の先端からＬｍｍの部分か
らＬ′ｍｍの部分まで非画像領域とする場合、あらかじ
めＬとＬ′を制御回路部（マイコン）１４０（図３９参
照）に入力する。原稿Ｄを原稿ガラス１５１へ搬送する
ときに原稿センサ（例えばフォトセンサ、不図示）によ
って原稿先端を検知し、先端からＬｍｍからＬ′ｍｍに
あたる部分のときに非画像領域を形成するように印加電
圧中心をシフトさせることにより、原稿Ｄの先端Ｌｍｍ
からＬ′ｍｍにあたる部分の画像形成を禁止することが
できる。That is, when the non-image area is formed from the portion Lmm to the portion L'mm from the leading edge of the document, L and L'are input in advance to the control circuit unit (microcomputer) 140 (see FIG. 39). When the document D is conveyed to the document glass 151, a document sensor (for example, a photo sensor, not shown) detects the document front end, and an applied voltage is applied so as to form a non-image area at a portion from Lmm to L'mm from the front end. By shifting the center, the leading edge Lmm of the document D
It is possible to prohibit the image formation of a portion corresponding to L'mm.

【００５２】（２）また、原稿Ｄを縮小して画像形成を
する場合などは、画像長さが転写材長よりも短いことが
多く、この場合は、露光走査に所定に同期させて、帯電
部材１０３に対する印加電圧をシフト制御する。(2) When the original D is reduced to form an image, the image length is often shorter than the transfer material length. In this case, charging is performed in synchronization with the exposure scanning in a predetermined manner. The voltage applied to the member 103 is shift-controlled.

【００５３】これら（１）、（２）の場合には画像先後
端部が転写材Ｐの端部付近になるときは限らず転写材の
中央付近になることもあり、この部分についても、より
シャープでかつ、高濃度部と中間調部のズレを小さくす
るべきである。この場合も、前述と同様、 ｘ≦Ｔ・ｖPS≦１０ｍｍ を満たすようにするとよい。さらに好ましくは、 ｘ≦Ｔ・ｖPS≦８ｍｍ とするとよい。In these cases (1) and (2), the image front / rear end portion is not always near the end portion of the transfer material P but may be near the center of the transfer material P. It should be sharp and the deviation between the high density area and the halftone area should be small. Also in this case, it is preferable to satisfy x ≦ T · v PS ≦ 10 mm, as described above. More preferably, x ≦ T · v PS ≦ 8 mm.

【００５４】以上に示した実施例は、帯電部材に印加す
る振動電圧の振動中心をシフト制御するものであるが、
帯電部材１０３に直流電圧ＤＣを印加し、これをシフト
させてもよい。直流電圧ＤＣ印加のときには、印加電圧
と帯電開始電圧の差電位に感光体が帯電される。したが
って、例えば１０２や帯電部材１０３の特性によって決
まる帯電開始電圧が５５０Ｖの場合、 （１）画像形成時には、−１１５０Ｖ、非画像形成時に
は−５５０Ｖにシフト制御する。 （２）また、例えば、非画像形成時に−８５０Ｖ印加
し、実施例２のように感光体１０２を中間電位（−３０
０Ｖ）に帯電させ、現像バイアスを同期させて、例え
ば、−３５０Ｖにシフトさせることにより、非画像領域
を形成させてもよい。In the above-described embodiment, the vibration center of the vibration voltage applied to the charging member is shift-controlled,
A DC voltage DC may be applied to the charging member 103 to shift it. When the DC voltage DC is applied, the photoconductor is charged to the potential difference between the applied voltage and the charging start voltage. Therefore, for example, when the charging start voltage determined by the characteristics of 102 and the charging member 103 is 550V, (1) shift control is performed to -1150V during image formation and -550V during non-image formation. (2) Further, for example, −850 V is applied at the time of non-image formation, and the photoconductor 102 is applied with an intermediate potential (−30 V) as in the second embodiment.
Alternatively, the non-image area may be formed by charging to 0 V), synchronizing the developing bias, and shifting to −350 V, for example.

【００５５】なお、前述した例は、ローラ形状の帯電部
材で説明したが、本発明はこれに限らず、例えば、ブレ
ードタイプ、ブラシ形状タイプ等、他の接触タイプの帯
電手段を適用することも可能である。In the above example, the roller-shaped charging member has been described, but the present invention is not limited to this, and other contact type charging means such as a blade type and a brush type may be applied. It is possible.

【００５６】[0056]

【発明の効果】以上説明したように、本発明によれば、
転写部材の汚れを防止し、転写メモリを発生を生じるこ
となく、転写材上にシャープなブランク領域を形成する
ことができる。また、像担持体を帯電する帯電部材に印
加する電圧を複雑に切換え制御しなくて良い。As described above, according to the present invention,
It is possible to prevent the transfer member from being soiled and form a sharp blank area on the transfer material without generating a transfer memory. Further, the voltage applied to the charging member for charging the image bearing member need not be complicatedly switched and controlled.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明の画像形成装置の概略を示す断面図。FIG. 1 is a sectional view showing the outline of an image forming apparatus of the present invention.

【図２】帯電部材による帯電領域を示す断面図。FIG. 2 is a cross-sectional view showing a charging region by a charging member.

【図３】画像先端近傍における高濃度部と中間濃度部の
感光体電位を示すグラフを示す図。FIG. 3 is a diagram showing a graph showing the photoconductor potentials of a high density portion and an intermediate density portion in the vicinity of the leading edge of an image.

【図４】画像形成装置の帯電器、現像器のタイミングチ
ャート。FIG. 4 is a timing chart of a charging device and a developing device of the image forming apparatus.

【図５】画像形成装置の帯電器、現像器及び転写帯電器
のタイミングチャート。FIG. 5 is a timing chart of a charging device, a developing device, and a transfer charging device of the image forming apparatus.

【符号の説明】[Explanation of symbols]

１０２ 感光体 １０３ 帯電部材 １０８Ａ 転写部材 102 Photoconductor 103 Charging Member 108A Transfer Member

Claims (6)

【特許請求の範囲】[Claims] 【請求項１】 画像を担持する像担持体と、 上記像担持体を帯電する帯電部材であって、この帯電部
材による帯電を用いて上記像担持体にはトナー像が形成
される帯電部材と、 上記トナー像を上記像担持体から転写材へ転写する転写
手段であって、この転写手段は、転写材の、上記像担持
体の側とは、逆側に接する転写部材を有し、転写位置に
転写材なしで、上記像担持体の第１領域が通過する間、
上記転写部材には上記帯電部材の帯電極性と逆極性の電
圧が印加される転写手段と、 上記像担持体の移動方向において転写材の端部を含むブ
ランク領域を形成するために上記帯電材に印加する電位
を切り換え制御する制御手段と、を有する画像形成装置
において、 上記第１領域と、上記ブランク領域に対応する上記像担
持体の第２領域と、はあらかじめ上記帯電部材によって
同じ所定電位が付与されることを特徴とする画像形成装
置。1. An image carrier for carrying an image, a charging member for charging the image carrier, and a charging member for forming a toner image on the image carrier by charging by the charging member. A transfer means for transferring the toner image from the image carrier to a transfer material, the transfer means having a transfer member in contact with a side of the transfer material opposite to the image carrier side, While the first region of the image carrier passes without the transfer material in position,
A transfer unit to which a voltage having a polarity opposite to the charging polarity of the charging member is applied to the transfer member, and the charging member is formed to form a blank area including an end portion of the transfer material in the moving direction of the image carrier. In the image forming apparatus having a control unit for switching and controlling the applied potential, the same predetermined potential is previously set by the charging member in the first region and the second region of the image carrier corresponding to the blank region. An image forming apparatus characterized by being provided. 【請求項２】 上記装置は、上記帯電部材による帯電を
用いて、上記像担持体をトナーで現像する現像手段を有
し、上記ブランク領域を形成するために上記現像手段に
印加される電位は切り換えられることを特徴とする請求
項１の画像形成装置。2. The apparatus has a developing means for developing the image carrier with toner by using charging by the charging member, and a potential applied to the developing means for forming the blank area is The image forming apparatus according to claim 1, wherein the image forming apparatus is switched. 【請求項３】 上記ブランク領域に対応する、上記像担
持体の領域は、転写材上の画像領域に対応する、上記像
担持体の領域よりもあらかじめ上記帯電部材によって低
い電位とされ、かつＯＶでない電位とされることを特徴
とする請求項１又は２の画像形成装置。3. The area of the image carrier corresponding to the blank area is set to a lower potential by the charging member in advance than the area of the image carrier corresponding to the image area on the transfer material, and OV. The image forming apparatus according to claim 1, wherein the image forming apparatus has a non-potential. 【請求項４】 上記帯電部材の帯電極性とは逆極性の電
圧は、上記トナー像の帯電極性と同極性であることを特
徴とする請求項１乃至３の画像形成装置。4. The image forming apparatus according to claim 1, wherein the voltage having a polarity opposite to the charging polarity of the charging member has the same polarity as the charging polarity of the toner image. 【請求項５】 上記転写位置に上記第１領域が通過する
間、上記転写部材に付着したトナーは、上記像担持体へ
移されることが可能であることを特徴とする請求項４の
画像形成装置。5. The image forming method according to claim 4, wherein the toner adhering to the transfer member can be transferred to the image carrier while the first region passes to the transfer position. apparatus. 【請求項６】 上記帯電部材は、上記像担持体を帯電す
るために、上記像担持体に接触可能であることを特徴と
する請求項１乃至５の画像形成装置。6. The image forming apparatus according to claim 1, wherein the charging member is capable of contacting the image carrier to charge the image carrier.
JP6174092A 1994-07-26 1994-07-26 Image forming device Withdrawn JPH0844155A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6174092A JPH0844155A (en) 1994-07-26 1994-07-26 Image forming device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6174092A JPH0844155A (en) 1994-07-26 1994-07-26 Image forming device

Publications (1)

Publication Number Publication Date
JPH0844155A true JPH0844155A (en) 1996-02-16

Family

ID=15972519

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6174092A Withdrawn JPH0844155A (en) 1994-07-26 1994-07-26 Image forming device

Country Status (1)

Country Link
JP (1) JPH0844155A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010079260A (en) * 2008-08-29 2010-04-08 Canon Inc Image forming apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010079260A (en) * 2008-08-29 2010-04-08 Canon Inc Image forming apparatus

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