JPH07271213A - Image forming device - Google Patents
Image forming deviceInfo
- Publication number
- JPH07271213A JPH07271213A JP6157794A JP6157794A JPH07271213A JP H07271213 A JPH07271213 A JP H07271213A JP 6157794 A JP6157794 A JP 6157794A JP 6157794 A JP6157794 A JP 6157794A JP H07271213 A JPH07271213 A JP H07271213A
- Authority
- JP
- Japan
- Prior art keywords
- transfer
- transfer belt
- image
- image forming
- charge
- 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.)
- Granted
Links
Landscapes
- Electrostatic Charge, Transfer And Separation In Electrography (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、電子写真プロセスを
用いたレ−ザプリンタ等の光プリンタ，複写機，フアク
シミリ装置等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 an optical printer such as a laser printer using an electrophotographic process, a copying machine, and a facsimile machine.
【０００２】[0002]
【従来の技術】レ−ザプリンタ等の電子写真方式の画像
形成装置においては、ドラム状又はベルト状の感光体
（像担持体）の表面を帯電器によって帯電した後、露光
装置により露光して静電潜像を形成し、その潜像を現像
装置からの現像剤により顕像化した後、それを転写装置
を用いて給紙装置からの転写材（転写紙，ＯＨＰシ−ト
等）上に転写し、定着装置によって定着するようにして
いる。2. Description of the Related Art In an electrophotographic image forming apparatus such as a laser printer, the surface of a drum-shaped or belt-shaped photosensitive member (image carrier) is charged by a charger and then exposed by an exposure device. An electrostatic latent image is formed, the latent image is visualized with a developer from a developing device, and then the latent image is transferred onto a transfer material (transfer paper, OHP sheet, etc.) from a paper feeding device using a transfer device. It is then transferred to and fixed by a fixing device.
【０００３】このような画像形成装置における転写装置
として従来よりコロナ転写帯電器が用いられている。コ
ロナ転写帯電器による転写プロセスを詳述すると、コロ
ナ放電によって転写材に電荷が付与されることにより、
転写材と像担持体表面との間に電界が作られ、その電界
により電荷をもった現像剤（トナ−）が転写材側に引き
付けられて転写される。A corona transfer charger is conventionally used as a transfer device in such an image forming apparatus. The transfer process by the corona transfer charger will be described in detail. By applying a charge to the transfer material by corona discharge,
An electric field is created between the transfer material and the surface of the image carrier, and the developer (toner) having a charge is attracted to the transfer material side by the electric field and transferred.
【０００４】そして、コロナ転写帯電器による転写プロ
セスにおいては転写材に付与された電荷により転写材が
像担持体に静電的に吸着されるため、転写後に転写材を
像担持体から分離するために転写材の電荷を適度に除去
する除電装置が必要となる。この除電プロセスは転写材
の電荷を除去し過ぎるとトナ−を吸引する力が弱くなっ
て転写不良を発生し、逆に電荷の除去が少な過ぎると転
写材の分離を行うことができなくなる。ところが、コロ
ナ転写帯電器によって転写材に付与される電荷量が環境
等によって変化するため、常に適切な除電を行うことは
困難であり、除電プロセスのバラツキにより分離不良あ
るいは転写不良が発生していた。In the transfer process using the corona transfer charger, the transfer material is electrostatically adsorbed to the image carrier by the charge applied to the transfer material, so that the transfer material is separated from the image carrier after the transfer. In addition, a static eliminator that appropriately removes the charge of the transfer material is required. In this static elimination process, if the charge of the transfer material is removed too much, the force of attracting the toner becomes weak and transfer failure occurs. On the contrary, if the charge is removed too little, the transfer material cannot be separated. However, since the amount of electric charge applied to the transfer material by the corona transfer charger changes depending on the environment and the like, it is difficult to always perform proper charge removal, and due to variations in the charge removal process, separation defects or transfer defects occurred. .
【０００５】上記問題点を解決するために、近年電圧が
印加された中抵抗の転写ベルトにより転写紙を搬送しつ
つ感光ドラム表面に接触させて転写を行うベルト転写方
式が用いられるようになった。図２に、ベルト転写方式
を採用した従来の画像形成装置の一例を示す。図２にお
いて、転写紙１０は、搬送ロ−ラ対１１によって入り口
ガイド板１２、１３にガイドされつつ搬送され、感光体
ドラム１と転写ベルト２の接触部近傍へ至る。そして、
転写紙１０は矢印方向Ａへ回転する感光体ドラム１と、
中抵抗の材質により形成され駆動ロ−ラ３と従動ロ−ラ
４に巻装されて矢印Ｂ方向へ回動する転写ベルト２に挟
まれて感光体ドラム１の表面と接触する。In order to solve the above problems, in recent years, a belt transfer system has been used in which transfer is performed by a transfer belt having a medium resistance to which a voltage is applied and the transfer paper is brought into contact with the surface of the photosensitive drum to perform transfer. . FIG. 2 shows an example of a conventional image forming apparatus adopting a belt transfer method. In FIG. 2, the transfer paper 10 is conveyed while being guided by the entrance guide plates 12 and 13 by the conveyance roller pair 11, and reaches the vicinity of the contact portion between the photosensitive drum 1 and the transfer belt 2. And
The transfer paper 10 is a photosensitive drum 1 that rotates in the direction of arrow A,
It is made of a medium resistance material, is wound around a driving roller 3 and a driven roller 4, and is sandwiched by a transfer belt 2 which rotates in the direction of arrow B, and comes into contact with the surface of the photosensitive drum 1.
【０００６】この時、バイアス印加ロ−ラ５には電源２
０によって電圧が印加されている。従って、転写紙１０
は感光ドラム１との接触部において転写ベルト２の有す
る電荷が発生する電界によってトナ−の転写を受ける。
ここで、転写紙１０の転写ベルト２に接触する面は転写
ベルト２の有する電荷により誘電分極していて転写紙１
０が転写ベルト２に静電的に吸着されているため、何ら
特別な手段を設けること無く転写紙１０は感光ドラム１
から容易に分離される。従って、このような中抵抗の転
写ベルトを備えたベルト転写方式を採用した画像形成装
置においては、感光ドラム１からの転写紙１０の分離性
は非常に良好である。At this time, the bias applying roller 5 has a power supply 2
A voltage is applied by 0. Therefore, the transfer paper 10
Is transferred by the toner by the electric field generated by the electric charge of the transfer belt 2 at the contact portion with the photosensitive drum 1.
Here, the surface of the transfer paper 10 in contact with the transfer belt 2 is dielectrically polarized by the electric charge of the transfer belt 2 and
Since 0 is electrostatically adsorbed on the transfer belt 2, the transfer paper 10 is transferred to the photosensitive drum 1 without providing any special means.
Easily separated from. Therefore, in the image forming apparatus adopting the belt transfer system having such a medium resistance transfer belt, the separability of the transfer paper 10 from the photosensitive drum 1 is very good.
【０００７】そして、転写を受けた転写紙１０は転写ベ
ルト２によって吸着されつつ搬送され駆動ロ−ラ３の位
置で転写ベルト２から分離される。ここで、バイアス印
加ロ−ラ５と駆動ロ−ラ３の間の転写ベルト２の内周面
には電源２０に接続された金属板であるフィ−ドバック
板６が接触配置されていて、駆動ロ−ラ３近傍の転写ベ
ルト２の電位は低電位となっているため、転写紙１０は
転写ベルト２から容易に分離される。そして、転写紙１
０は出口ガイド板１４、１５にガイドされて定着ロ−ラ
対１６に搬送され転写紙１０上のトナ−画像は定着され
る。Then, the transfer paper 10 having undergone the transfer is conveyed while being attracted by the transfer belt 2 and separated from the transfer belt 2 at the position of the driving roller 3. Here, a feed back plate 6 which is a metal plate connected to a power source 20 is disposed in contact with the inner peripheral surface of the transfer belt 2 between the bias applying roller 5 and the driving roller 3 for driving. Since the electric potential of the transfer belt 2 near the roller 3 is low, the transfer paper 10 is easily separated from the transfer belt 2. And the transfer paper 1
0 is guided by the exit guide plates 14 and 15 and conveyed to the fixing roller pair 16 so that the toner image on the transfer paper 10 is fixed.
【０００８】[0008]
【発明が解決しようとする課題】しかしながら、従来の
ベルト転写方式を採用した画像形成装置においては、黒
ポチ状や水玉状の異常画像が発生するという問題があっ
た。これは、転写紙１０が感光ドラム１から分離すると
きに、転写ベルト２の有する電荷により感光ドラム１と
転写紙１０との間に剥離放電が発生して転写紙１０のト
ナ−像担持面側に電荷が付与される。そして、転写紙１
０の転写部下流の搬送過程において転写紙１０のトナ−
像非担持面が導電性のガイド板等に接触したときに、転
写紙１０のトナ−像担持面側の電荷が放電する。この時
の電荷の移動によりトナ−が移動して上述のような異常
画像が発生するものと考えられる。However, the image forming apparatus adopting the conventional belt transfer system has a problem in that a black spot-like or polka dot-like abnormal image occurs. This is because when the transfer paper 10 is separated from the photosensitive drum 1, peeling discharge occurs between the photosensitive drum 1 and the transfer paper 10 due to the electric charge of the transfer belt 2, and the toner image bearing surface side of the transfer paper 10 is generated. Is charged. And the transfer paper 1
Toner of the transfer paper 10 in the conveying process downstream of the transfer unit 0
When the image non-bearing surface contacts a conductive guide plate or the like, the charge on the toner image bearing surface side of the transfer paper 10 is discharged. It is considered that the toner moves due to the movement of the electric charges at this time and the abnormal image as described above is generated.
【０００９】この発明は上記の点に鑑みてなされたもの
であり、転写材の像担持体からの分離性が良好であっ
て、画像品質が向上した画像形成装置を提供することを
目的とする。The present invention has been made in view of the above points, and an object of the present invention is to provide an image forming apparatus in which the separation property of the transfer material from the image carrier is good and the image quality is improved. .
【００１０】[0010]
【課題を解決するための手段】この発明は上記の目的を
達成するため、電気抵抗が中抵抗である材料により形成
され、転写部を通過するように転写材を担持搬送し、像
担持体上に形成された画像を印加された電圧によって静
電的に転写材に転写させる転写ベルトを備えた画像形成
装置において、上記転写ベルトの移動方向に関して上記
転写部の下流に配設され、上記転写ベルトの転写材担持
面に向けて帯電を行う直流電圧が印加された帯電手段を
設けたものである。In order to achieve the above-mentioned object, the present invention is made of a material having an electric resistance of medium resistance, and carries and conveys a transfer material so as to pass through the transfer portion, and In an image forming apparatus including a transfer belt for electrostatically transferring an image formed on a transfer material to a transfer material by an applied voltage, the transfer belt is disposed downstream of the transfer unit in the moving direction of the transfer belt. The charging means is provided with a direct current voltage for charging the transfer material carrying surface.
【００１１】上記画像形成装置において、上記帯電手段
はスコロトロン帯電器で構成すると良い。また、上記直
流電圧の極性は、上記転写ベルトに印加される電圧の極
性と同極性にすると良い。In the image forming apparatus, the charging means may be a scorotron charger. The polarity of the DC voltage may be the same as the polarity of the voltage applied to the transfer belt.
【００１２】[0012]
【作用】この発明によれば、転写ベルトによってトナ−
像の転写を受けた転写材のトナ−像担持面の電荷の分布
が不均一であっても、直流電圧が印加された帯電手段に
よりこれが一様とされるため、転写後の搬送途中で転写
材のトナ−像担持面に付与された電荷が放電しても、異
常画像となることが防止される。According to the present invention, the toner is transferred by the transfer belt.
Even if the charge distribution on the toner image bearing surface of the transfer material that has received the image transfer is non-uniform, the charge is made uniform by the charging means to which a DC voltage is applied. Even if the electric charge applied to the toner image bearing surface of the material is discharged, an abnormal image is prevented.
【００１３】また、この発明によれば、帯電手段がスコ
ロトロン帯電手段であるため、その特性により転写材の
トナ−像担持面に付与された電荷は良好に一様とされ、
転写後の搬送途中で転写材のトナ−像担持面に付与され
た電荷が放電しても、異常画像となることが防止され
る。Further, according to the present invention, since the charging means is the scorotron charging means, the charge imparted to the toner image bearing surface of the transfer material is made uniform due to its characteristics.
Even if the charge applied to the toner image bearing surface of the transfer material is discharged during the transportation after the transfer, an abnormal image is prevented.
【００１４】また、この発明によれば、帯電手段に印加
される直流電圧の極性が、転写ベルトに印加される電圧
の極性と同極性であり、転写材のトナ−像担持面に付与
された電荷と逆極性であるため、転写材のトナ−像担持
面に付与された電荷は良好に一様とされ、転写後の搬送
途中で転写材のトナ−像担持面に付与された電荷が放電
しても、異常画像となることが防止される。Further, according to the present invention, the polarity of the DC voltage applied to the charging means is the same as the polarity of the voltage applied to the transfer belt, and the polarity is applied to the toner image bearing surface of the transfer material. Since the polarity is opposite to that of the charge, the charge applied to the toner image bearing surface of the transfer material is made uniform, and the charge applied to the toner image bearing surface of the transfer material is discharged during conveyance after transfer. Even if it is, an abnormal image is prevented.
【００１５】[0015]
【実施例】以下、この発明の実施例を添付図面に基づい
て具体的に説明する。図１は、この発明の画像形成装置
の一実施例を示す要部構成図であり、図２と同じ部分に
は同一符号を付している。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 is a main part configuration diagram showing an embodiment of an image forming apparatus of the present invention, and the same parts as those in FIG. 2 are designated by the same reference numerals.
【００１６】図１において、光導電性の感光体ドラム１
は像担持体であり、転写されるべきトナ−画像を周面に
保持して矢印Ａ方向へ回転する。転写ベルト２は二層構
造であって、感光体ドラム１と接触する側の表面層は電
気抵抗が１×１０9Ω〜１×１０12Ωの材料で、バイア
ス印加ロ−ラ５と接触する側の裏面層は電気抵抗が１×
１０9Ω〜１×１０12Ωの材料で構成されている。そし
て、転写ベルト２は駆動ロ−ラ３と従動ロ−ラ４とに巻
装され、駆動ロ−ラ３により反時計回りに（矢印Ｂ方
向）に回動される。In FIG. 1, a photoconductive photosensitive drum 1 is shown.
Is an image carrier, which holds the toner image to be transferred on the peripheral surface and rotates in the direction of arrow A. The transfer belt 2 has a two-layer structure, and the surface layer on the side in contact with the photosensitive drum 1 is made of a material having an electric resistance of 1 × 10 9 Ω to 1 × 10 12 Ω, and contacts the bias applying roller 5. Side back layer has an electrical resistance of 1 ×
It is made of a material of 10 9 Ω to 1 × 10 12 Ω. The transfer belt 2 is wound around the driving roller 3 and the driven roller 4, and is rotated counterclockwise (in the direction of arrow B) by the driving roller 3.
【００１７】駆動ロ−ラ３は金属ロ−ラの外周面に、転
写ベルト２との摩擦係合を高めるためのゴム層を形成さ
れ、図示しない駆動機構により反時計回りに回転され
る。従動ロ−ラ４は金属ロ−ラである。The drive roller 3 has a rubber layer formed on the outer peripheral surface of the metal roller for enhancing frictional engagement with the transfer belt 2, and is rotated counterclockwise by a drive mechanism (not shown). The driven roller 4 is a metal roller.
【００１８】バイアス印加ロ−ラ５は金属ロ−ラであっ
て、感光体ドラム１と転写ベルト２との接触部から駆動
ロ−ラ３側へ所定距離ずれた位置において転写ベルト２
の内周面に当接し、転写ベルト２の回動に従動して回転
する。フィ−ドバック板６は金属板であって、バイアス
印加ロ−ラ５と駆動ロ−ラ３との間で転写ベルト２の内
周面に接触している。バイアス印加ロ−ラ５およびフィ
−ドバック板６は共に電源２０に接続されている。The bias applying roller 5 is a metal roller, and is located at a position displaced from the contact portion between the photosensitive drum 1 and the transfer belt 2 toward the drive roller 3 by a predetermined distance.
It contacts the inner peripheral surface of the transfer belt 2 and rotates following the rotation of the transfer belt 2. The feedback plate 6 is a metal plate, and is in contact with the inner peripheral surface of the transfer belt 2 between the bias applying roller 5 and the driving roller 3. The bias applying roller 5 and the feedback plate 6 are both connected to the power source 20.
【００１９】トナ−画像転写時には、反時計方向へ回動
する転写ベルト２の従動ロ−ラ４側から転写紙１０が給
紙される。即ち、転写紙１０は搬送ロ−ラ対１１によっ
て入り口ガイド板１２、１３に沿って転写部である感光
体ドラム１と転写ベルト２の接触部近傍へ搬送される。
そして、転写紙１０は感光体ドラム１と転写ベルト２に
挟まれて両者の回転に伴って図中左方へ搬送される。転
写時には、電源２０からバイアス印加ロ−ラ５に電圧が
印加され、電流Ｉ1が流れる。この電流Ｉ1 の一部は電
気抵抗が中抵抗である転写ベルト２中を右方へ流れて転
写電流Ｉ2 となり、感光体ドラム１上のトナ−画像を転
写紙１０に転写させる。電流Ｉ1 の残りの部分Ｉ3 は転
写ベルト２中を流れてフィ−ドバック板６から電源２０
へ戻る。During toner image transfer, the transfer paper 10 is fed from the driven roller 4 side of the transfer belt 2 which rotates counterclockwise. That is, the transfer paper 10 is transported by the transport roller pair 11 along the entrance guide plates 12 and 13 to the vicinity of the contact portion between the photosensitive drum 1 and the transfer belt 2, which is the transfer portion.
Then, the transfer paper 10 is sandwiched between the photosensitive drum 1 and the transfer belt 2, and is conveyed to the left in the drawing as the two rotate. At the time of transfer, a voltage is applied to the bias applying roller 5 from the power source 20 and a current I 1 flows. A part of this current I 1 flows rightward through the transfer belt 2 having an electric resistance of medium resistance and becomes a transfer current I 2 , and the toner image on the photosensitive drum 1 is transferred onto the transfer paper 10. The remaining portion I 3 of the current I 1 flows through the transfer belt 2 and is fed from the feedback plate 6 to the power source 20.
Return to.
【００２０】このようなベルト転写方式においては、バ
イアス印加ロ−ラ５に印加する電圧を一定に保った場
合、環境変動による転写ベルト２，転写紙１０の抵抗値
の変化、転写ベルト２自体の抵抗ムラ、転写紙１０の種
類、感光ドラム１上に形成される画像部の面積等により
バイアス印加ロ−ラ５と感光ドラム１との間の抵抗値が
変化するため、感光ドラム１へ流れる転写電流Ｉ2 が変
化する。感光ドラム１へ流れる転写電流が変化するとこ
れに伴い転写効率が変化して安定した画像の形成を行う
ことができなくなる。In such a belt transfer system, when the voltage applied to the bias applying roller 5 is kept constant, a change in the resistance value of the transfer belt 2 and the transfer paper 10 due to environmental changes, and the transfer belt 2 itself. Since the resistance value between the bias applying roller 5 and the photosensitive drum 1 changes depending on the resistance unevenness, the type of the transfer paper 10, the area of the image portion formed on the photosensitive drum 1, etc., the transfer to the photosensitive drum 1 is performed. The current I 2 changes. When the transfer current flowing to the photosensitive drum 1 changes, the transfer efficiency changes accordingly, and stable image formation cannot be performed.
【００２１】従って、電源から流れ出る電流Ｉ1 とフィ
−ドバック板６から電源２０へ流れる電流Ｉ3 との差が
一定となるように電源２０の電圧を制御することが従来
より行われている。これによって、感光ドラム１へ流れ
る転写電流Ｉ2 を一定に保つことができ、所定の転写効
率を維持することができる。本実施例においては、トナ
−の極性はプラス極性であって、転写電流Ｉ2 が−５０
μＡとなるように設定されているTherefore, it has been conventionally practiced to control the voltage of the power source 20 so that the difference between the current I 1 flowing from the power source and the current I 3 flowing from the feedback plate 6 to the power source 20 becomes constant. As a result, the transfer current I 2 flowing to the photosensitive drum 1 can be kept constant, and a predetermined transfer efficiency can be maintained. In this embodiment, the toner has a positive polarity and the transfer current I 2 is -50.
It is set to be μA
【００２２】こうして、転写部においてトナ−画像の転
写を受けた転写紙１０は転写ベルト２によって搬送され
駆動ロ−ラ３の位置に至る。このとき、上述のようにバ
イアス印加ロ−ラ５と駆動ロ−ラ３の間の転写ベルト２
の内周面には電源２０に接続された金属板であるフィ−
ドバック板６が接触配置されていて、駆動ロ−ラ３近傍
の転写ベルト２の電位は低電位となっているため、転写
紙１０は転写ベルト２から容易に分離される。そして、
転写紙１０は出口ガイド板１４、１５にガイドされて定
着ロ−ラ対１６に搬送され転写紙１０上のトナ−画像は
定着される。In this way, the transfer paper 10 having the toner image transferred at the transfer portion is conveyed by the transfer belt 2 and reaches the position of the drive roller 3. At this time, as described above, the transfer belt 2 between the bias applying roller 5 and the driving roller 3
A metal plate connected to the power source 20 is provided on the inner peripheral surface of the fuse.
Since the duck back plate 6 is arranged in contact with the transfer belt 2 in the vicinity of the driving roller 3 and the electric potential of the transfer belt 2 is low, the transfer paper 10 is easily separated from the transfer belt 2. And
The transfer paper 10 is guided by the exit guide plates 14 and 15 and conveyed to the fixing roller pair 16 so that the toner image on the transfer paper 10 is fixed.
【００２３】そして、このような装置においては、前述
のように転写紙１０の転写部下流の搬送時において、転
写紙１０のトナ−像担持面側の電荷が放電して異常画像
が発生する。これを解消するためには、転写紙１０のト
ナ−像担持面側の電荷を除電することが考えられるが、
完全にこの電荷を除去すべく除電するには大きな電圧を
必要とする。In such an apparatus, when the transfer paper 10 is conveyed downstream of the transfer portion as described above, the charge on the toner image bearing surface side of the transfer paper 10 is discharged and an abnormal image is generated. In order to eliminate this, it is conceivable to eliminate the charge on the toner image bearing surface side of the transfer paper 10.
A large voltage is needed to completely eliminate this charge.
【００２４】上記放電現象に関して実験を重ねたとこ
ろ、異常画像の程度は転写紙１０のトナ−像担持面側の
電荷の総量よりも、その電荷の分布の均一性に密接な関
係があることが判った。即ち、転写紙１０のトナ−像担
持面側の電荷の総量が多い場合でもその電荷の分布が均
一である場合には異常画像の程度は低く、その電荷の総
量が少ない場合であってもその電荷の分布が不均一であ
ると異常画像の程度が高い。As a result of repeated experiments on the above-mentioned discharge phenomenon, the degree of the abnormal image is more closely related to the uniformity of the electric charge distribution than the total amount of electric charges on the toner image bearing surface side of the transfer paper 10. understood. That is, even if the total amount of charges on the toner image bearing surface side of the transfer paper 10 is large, the degree of abnormal image is low if the distribution of the charges is uniform, and even if the total amount of charges is small, If the charge distribution is not uniform, the degree of abnormal image is high.
【００２５】従って、本実施例においては、転写ベルト
２の移動方向に関して転写部の下流側に、転写ベルト２
の外周面に向けてコロナチャ−ジャ２１が配設されてい
る。そして、転写紙１０がコロナチャ−ジャ２１の作用
部に到達したときに、転写紙１０のトナ−画像担持面の
電荷を一様にすべく−６ｋＶの直流電圧が印加され転写
紙１０に電荷が付与される。これによって、転写紙１０
の表面に発生した電荷は一様とされ、この電荷によって
引き起こされる異常画像の発生が解消される。Therefore, in this embodiment, the transfer belt 2 is provided on the downstream side of the transfer portion in the moving direction of the transfer belt 2.
The corona charger 21 is arranged toward the outer peripheral surface of the. Then, when the transfer paper 10 reaches the operating portion of the corona charger 21, a DC voltage of −6 kV is applied so that the charge on the toner image bearing surface of the transfer paper 10 is evenly applied, and the transfer paper 10 is charged. Granted. As a result, the transfer paper 10
The charges generated on the surface of the are uniformized, and the occurrence of an abnormal image caused by the charges is eliminated.
【００２６】ところで、コロナチャ−ジャ２１は転写紙
１０のトナ−画像担持面の電荷を一様にするものである
から、そのような特性を顕著に有するスコロトロン帯電
器であることが好ましい。また、コロナチャ−ジャ２１
に印加される電圧の極性は、転写紙１０のトナ−画像担
持面の電荷を一様にするという点で転写紙１０上のトナ
−や剥離放電によって付与された電荷と同極性であって
も効果を有するが、逆極性である方がその効果は大き
い。従って、コロナチャ−ジャ２１に印加される電圧の
極性は、転写ベルト２に印加される電圧の極性と同極性
であることが好ましい。By the way, since the corona charger 21 serves to make the charge on the toner image carrying surface of the transfer paper 10 uniform, it is preferable to use a scorotron charger having such characteristics remarkably. Also, Corona Charger 21
The polarity of the voltage applied to the transfer paper 10 is the same as that applied by the toner on the transfer paper 10 or the peeling discharge in that the charge on the toner image bearing surface of the transfer paper 10 is made uniform. It has an effect, but the effect is greater when the polarity is opposite. Therefore, the polarity of the voltage applied to the corona charger 21 is preferably the same as the polarity of the voltage applied to the transfer belt 2.
【００２７】[0027]
【発明の効果】以上説明したように、この発明によれ
ば、転写ベルトによってトナ−像の転写を受けた転写材
のトナ−像担持面の電荷の分布が不均一であっても、直
流電圧が印加された帯電手段によりこれが一様とされる
ため、転写後の搬送途中で転写材のトナ−像担持面に付
与された電荷が放電しても、異常画像となることが防止
される。従って、転写材の像担持体からの分離性が良好
であって、画像品質が向上した画像形成装置を提供でき
る。As described above, according to the present invention, even if the charge distribution on the toner image bearing surface of the transfer material having the toner image transferred by the transfer belt is non-uniform, a DC voltage is applied. Since this is made uniform by the charging means to which is applied, it is possible to prevent an abnormal image even if the charge applied to the toner image bearing surface of the transfer material is discharged during the transportation after the transfer. Therefore, it is possible to provide the image forming apparatus in which the transfer material has a good separability from the image carrier and the image quality is improved.
【００２８】また、この発明によれば、帯電手段がスコ
ロトロン帯電手段であるため、その特性により転写材の
トナ−像担持面に付与された電荷は良好に一様とされ、
転写後の搬送途中で転写材のトナ−像担持面に付与され
た電荷が放電しても、異常画像となることが防止され
る。従って、転写材の像担持体からの分離性が良好であ
って、画像品質が向上した画像形成装置を提供できる。Further, according to the present invention, since the charging means is the scorotron charging means, the charge imparted to the toner image bearing surface of the transfer material can be made uniform due to its characteristics.
Even if the charge applied to the toner image bearing surface of the transfer material is discharged during the transportation after the transfer, an abnormal image is prevented. Therefore, it is possible to provide the image forming apparatus in which the transfer material has a good separability from the image carrier and the image quality is improved.
【００２９】また、この発明によれば、帯電手段に印加
される直流電圧の極性が、転写ベルトに印加される電圧
の極性と同極性であり、転写材のトナ−像担持面に付与
された電荷と逆極性であるため、転写材のトナ−像担持
面に付与された電荷は良好に一様とされ、転写後の搬送
途中で転写材のトナ−像担持面に付与された電荷が放電
しても、異常画像となることが防止される。従って、転
写材の像担持体からの分離性が良好であって、画像品質
が向上した画像形成装置を提供できる。According to the present invention, the polarity of the DC voltage applied to the charging means is the same as the polarity of the voltage applied to the transfer belt and is applied to the toner image bearing surface of the transfer material. Since the polarity is opposite to that of the charge, the charge applied to the toner image bearing surface of the transfer material is made uniform, and the charge applied to the toner image bearing surface of the transfer material is discharged during conveyance after transfer. Even if it is, an abnormal image is prevented. Therefore, it is possible to provide the image forming apparatus in which the transfer material has a good separability from the image carrier and the image quality is improved.
【００３０】[0030]
【図１】この発明の第１の実施例を示す要部構成図であ
る。FIG. 1 is a main part configuration diagram showing a first embodiment of the present invention.
【図２】従来のベルト転写方式を採用した画像形成装置
の一例を示す要部構成図である。FIG. 2 is a main part configuration diagram showing an example of an image forming apparatus adopting a conventional belt transfer system.
１ 像担持体 ２ 転写ベルト ３ 駆動ロ−ラ ４ 従動ロ−ラ ５ バイアス印加ロ−ラ ６ フィ−ドバック板 １０ 転写紙 ２１ 帯電器 1 image carrier 2 transfer belt 3 driving roller 4 driven roller 5 bias applying roller 6 feed back plate 10 transfer paper 21 charger
Claims (3)
され、転写部を通過するように転写材を担持搬送し、像
担持体上に形成された画像を印加された電圧によって静
電的に転写材に転写させる転写ベルトを備えた画像形成
装置において、上記転写ベルトの移動方向に関して上記
転写部の下流に配設され、上記転写ベルトの転写材担持
面に向けて帯電を行う直流電圧が印加された帯電手段を
設けたことを特徴とする画像形成装置。1. A transfer material is formed of a material having an electric resistance of medium resistance, carries a transfer material so as to pass through a transfer portion, and electrostatically forms an image formed on an image carrier by an applied voltage. In an image forming apparatus equipped with a transfer belt for transferring to a transfer material, a DC voltage is applied which is arranged downstream of the transfer section in the moving direction of the transfer belt and charges the transfer material carrying surface of the transfer belt. An image forming apparatus, which is provided with an electrified charging unit.
上記帯電手段はスコロトロン帯電器であることを特徴と
する画像形成装置。2. The image forming apparatus according to claim 1, wherein
The image forming apparatus, wherein the charging means is a scorotron charger.
って、上記直流電圧の極性は、上記転写ベルトに印加さ
れる電圧の極性と同極性であることを特徴とする画像形
成装置。3. The image forming apparatus according to claim 1, wherein the polarity of the DC voltage is the same as the polarity of the voltage applied to the transfer belt.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06157794A JP3366419B2 (en) | 1994-03-30 | 1994-03-30 | Image forming device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06157794A JP3366419B2 (en) | 1994-03-30 | 1994-03-30 | Image forming device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07271213A true JPH07271213A (en) | 1995-10-20 |
| JP3366419B2 JP3366419B2 (en) | 2003-01-14 |
Family
ID=13175126
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP06157794A Expired - Fee Related JP3366419B2 (en) | 1994-03-30 | 1994-03-30 | Image forming device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3366419B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005301184A (en) * | 2004-04-16 | 2005-10-27 | Konica Minolta Business Technologies Inc | Image forming apparatus |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7184678B2 (en) | 2003-12-19 | 2007-02-27 | Ricoh Company, Limited | Image forming apparatus with improved separatability of transfer material |
-
1994
- 1994-03-30 JP JP06157794A patent/JP3366419B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005301184A (en) * | 2004-04-16 | 2005-10-27 | Konica Minolta Business Technologies Inc | Image forming apparatus |
| JP4608930B2 (en) * | 2004-04-16 | 2011-01-12 | コニカミノルタビジネステクノロジーズ株式会社 | Image forming apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3366419B2 (en) | 2003-01-14 |
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