JPH0962114A - Transfer device - Google Patents

Transfer device

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Publication number
JPH0962114A
JPH0962114A JP21728195A JP21728195A JPH0962114A JP H0962114 A JPH0962114 A JP H0962114A JP 21728195 A JP21728195 A JP 21728195A JP 21728195 A JP21728195 A JP 21728195A JP H0962114 A JPH0962114 A JP H0962114A
Authority
JP
Japan
Prior art keywords
transfer
pressure
toner
recording paper
belt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP21728195A
Other languages
Japanese (ja)
Inventor
Tomoki Kato
知己 加藤
Masafumi Kadonaga
雅史 門永
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.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
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 Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP21728195A priority Critical patent/JPH0962114A/en
Publication of JPH0962114A publication Critical patent/JPH0962114A/en
Pending legal-status Critical Current

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  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)

Abstract

PROBLEM TO BE SOLVED: To perform the transfer only in a transfer nip part, for making the image quality high, and to make an applied voltage for forming a transfer electric field low, for preventing an unwanted discharge by providing a pressure conductive member for transferring toner from an electrostatic charge image carrier to an intermediate transfer body. SOLUTION: The pressure conductive member 25 provided in the transfer nip part is pressed on a photoreceptor 21 by a pressure member 26, to come into contact with the photoreceptor 21 at a transfer position and a voltage having a polarity opposite to that of the charge of the toner stuck to the photoreceptor 21 from a developing means is applied to the pressure member 26 from a power source 27, to form the transfer electric field between the pressure conductive member 25 and the photoreceptor 21. The conductive member 25 is made of, for instance, silicone rubber where conductive metal grains and carbon black are uniformly dispersed, so that a great change in resistance is made by the application of pressure. When a recording paper 23 passes through between the photoreceptor 21 and the conductive member 25, a toner image on the photoreceptor 21 is transferred to the recording paper 23 by the transfer electric field.

Description

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

【０００１】[0001]

【発明の属する技術分野】本発明は複写機、ファクシミ
リ、プリンタ等の画像形成装置における転写装置に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer device in an image forming apparatus such as a copying machine, a facsimile and a printer.

【０００２】[0002]

【従来の技術】電子写真技術を利用した複写機、ファク
シミリ、プリンタ等の画像形成装置における画像形成プ
ロセスでは、感光体からなる静電像担持体に対して均一
な初期帯電を行った後に初期帯電を部分的に消去して静
電荷のパターンを形成し、該静電荷のパターンをトナー
により現像してトナー像とし、このトナー像を転写装置
により転写電界で記録紙上に転写している。2. Description of the Related Art In an image forming process in an image forming apparatus such as a copying machine, a facsimile or a printer, which uses electrophotography, a uniform initial charging is performed on an electrostatic image carrier, which is a photoconductor, and then an initial charging is performed. Is partially erased to form an electrostatic charge pattern, the electrostatic charge pattern is developed with toner to form a toner image, and the toner image is transferred onto a recording paper by a transfer electric field by a transfer device.

【０００３】この転写装置としては、従来から主にコロ
ナチャージャが使用されてきた。特開平６ー３３２３２
１号公報には、コロナチャージャにより感光体上のトナ
ー像を記録紙に転写し、転写後に記録紙の裏面をＡＣ除
電して剥離放電を防止するものが記載されている。しか
し、コロナチャージャは、コロナ放電によりオゾンを多
量に発生するので、昨今問題となっている。そこで、転
写装置は、オゾン発生量が少ない方式として、ベルトや
ローラを感光体に接触させて転写を行う方式が主流にな
りつつある。As the transfer device, a corona charger has been mainly used conventionally. Japanese Patent Laid-Open No. 6-33232.
Japanese Unexamined Patent Publication (Kokai) No. 1 describes that a toner image on a photoconductor is transferred to a recording sheet by a corona charger, and after the transfer, the back surface of the recording sheet is subjected to AC discharge to prevent peeling discharge. However, since the corona charger generates a large amount of ozone by corona discharge, it has become a problem these days. Therefore, as a transfer device, a system in which a belt or a roller is brought into contact with a photoconductor to perform transfer is becoming mainstream as a system in which a small amount of ozone is generated.

【０００４】この方式としては、中間転写ベルトからな
る中間転写体における転写部の裏側にゴムローラを設
け、このゴムローラに転写バイアスを印加して感光体か
ら中間転写ベルトにトナーを転写する方式が特開平６ー
３０１２９７号公報に記載されている。また、感光体に
導電性弾性転写ローラを加圧接触させて感光体から記録
紙にトナーを転写する方式が特開平６ー１６１３０４号
公報に記載され、転写ローラに加圧導電シートを装着し
てものが特開平７ー１３４４７号公報に記載されてい
る。これらの方式は、いずれも、中抵抗部材に電源から
高電圧を印加して転写電界を得ている。As this method, there is a method in which a rubber roller is provided on the back side of a transfer portion in an intermediate transfer member composed of an intermediate transfer belt, and a transfer bias is applied to this rubber roller to transfer toner from a photosensitive member to the intermediate transfer belt. No. 6-301297. Further, a method of transferring a toner from a photosensitive member to a recording paper by bringing a conductive elastic transfer roller into pressure contact with the photosensitive member is described in Japanese Patent Laid-Open No. 161304/1994, and a pressure conductive sheet is attached to the transfer roller. Those described in JP-A-7-13447. In all of these methods, a high voltage is applied from a power source to the medium resistance member to obtain a transfer electric field.

【０００５】図９は転写ローラを用いた転写装置の一例
を示す。転写ローラ３は芯金３ａに中抵抗の樹脂層３ｂ
を設けた構成になっており、芯金３ａには転写電界を生
成するための高電圧が電源６から印加される。また、転
写ローラ３は図示しない加圧機構により適当な加圧力で
感光体１に接触し、その接触部は図１０に示すようにあ
る幅のニップ部ｂを有する接触状態となっている。記録
紙２は、感光体１と転写ローラ３との間を通過する時に
感光体１からトナー４が転写され、ガイド板５により案
内されて定着装置へ送られる。FIG. 9 shows an example of a transfer device using a transfer roller. The transfer roller 3 includes a core metal 3a and a resin layer 3b having a medium resistance.
A high voltage for generating a transfer electric field is applied from the power source 6 to the core metal 3a. Further, the transfer roller 3 is brought into contact with the photosensitive member 1 by an appropriate pressing force by a pressure mechanism (not shown), and the contact portion is in a contact state having a nip portion b having a certain width as shown in FIG. When the recording paper 2 passes between the photoconductor 1 and the transfer roller 3, the toner 4 is transferred from the photoconductor 1, guided by the guide plate 5, and sent to the fixing device.

【０００６】また、画像形成装置において、記録紙を安
定に搬送する技術は、重要な技術の１つである。現在最
も安定性の高い記録紙搬送方式としては、記録紙をベル
トで静電的に吸着して搬送するベルト搬送方式がある。
この方式では、記録紙全体がベルトに吸着されるので、
感光体上のトナーを記録紙に転写する転写部などで記録
紙が感光体などに巻き付いてしまうなどのトラブルがな
く、高速に安定して記録紙を搬送することが可能であ
る。したがって、ベルトに記録紙を吸着させた状態でト
ナーを感光体から記録紙に転写するベルト転写方式は、
高速に高品位な画像が得られる優れた転写方式である。Further, in the image forming apparatus, the technique of stably conveying the recording paper is one of the important techniques. As the most stable recording paper conveyance method at present, there is a belt conveyance method in which recording paper is electrostatically adsorbed by a belt and conveyed.
In this method, the entire recording paper is attracted to the belt, so
It is possible to stably convey the recording paper at high speed without any trouble such as the recording paper being wound around the photosensitive body at a transfer portion or the like for transferring the toner on the photosensitive body to the recording paper. Therefore, the belt transfer method, in which the toner is transferred from the photoconductor to the recording paper while the recording paper is attracted to the belt,
It is an excellent transfer method that can obtain high-quality images at high speed.

【０００７】図１１はベルトを用いた転写装置の１例を
示す。転写搬送ベルト１１は摩擦係数の大きな素材で被
覆された駆動ローラ１２とテンションローラ１３に張架
されて駆動ローラ１２により回転駆動され、コロナ帯電
器１４は電源１５から高電圧が印加されてコロナ放電に
より転写搬送ベルト１１の裏面を帯電させる。記録紙１
６は、転写搬送ベルト１１により静電的に吸着されて搬
送され、感光体１７と転写搬送ベルト１１とにより形成
される転写ニップ部を通過する時に感光体１７上のトナ
ー像が転写される。FIG. 11 shows an example of a transfer device using a belt. The transfer / conveyance belt 11 is stretched between a driving roller 12 and a tension roller 13 which are covered with a material having a large friction coefficient, and is rotationally driven by the driving roller 12, and a high voltage is applied to a corona charger 14 from a power supply 15 to cause corona discharge. Thus, the back surface of the transfer / transport belt 11 is charged. Chart paper 1
6 is electrostatically attracted and conveyed by the transfer / conveyance belt 11, and a toner image on the photoreceptor 17 is transferred when passing through a transfer nip portion formed by the photoreceptor 17 and the transfer / conveyance belt 11.

【０００８】[0008]

【発明が解決しようとする課題】上記オゾン発生量が少
ない方式は、いずれも、中抵抗部材に電源から高電圧を
印加して転写電界を得ているので、電源のコストが高く
なる。また、電源から印加する高電圧の大きさによって
は、感光体と中間転写体との転写ニップ部以外の部分で
も転写電界が存在するので、感光体と記録紙との間の広
い空隙でトナーの移動が起こってしまい、画像劣化の原
因となる。In any of the above-mentioned methods that generate a small amount of ozone, a high voltage is applied from a power source to the medium resistance member to obtain a transfer electric field, so that the cost of the power source increases. In addition, depending on the magnitude of the high voltage applied from the power source, a transfer electric field exists even in a portion other than the transfer nip portion between the photoconductor and the intermediate transfer member. This causes movement, which causes image deterioration.

【０００９】また、上述した図９に示す転写装置では、
感光体１上のトナー４がニップ部ｂにおいてのみ記録紙
２に転写されることが画質の点から理想的であるが、転
写ローラ３の表面は転写ニップ部ｂ以外の部分ａ、ｃで
も高電圧になっているので、転写ニップ部ｂより前側の
部分ｃの空隙で、感光体１と記録紙２とが接触する前に
感光体１上のトナー４が記録紙２に転写されてしまうこ
とが生ずる。このような転写は画質劣化に結び付いてし
まう。Further, in the transfer device shown in FIG.
It is ideal from the viewpoint of image quality that the toner 4 on the photoconductor 1 is transferred to the recording paper 2 only at the nip portion b, but the surface of the transfer roller 3 is high at the portions a and c other than the transfer nip portion b. Since the voltage is applied, the toner 4 on the photoconductor 1 is transferred onto the recording paper 2 before the photoconductor 1 and the recording paper 2 come into contact with each other in the gap c on the front side of the transfer nip portion b. Occurs. Such transfer leads to deterioration of image quality.

【００１０】また、電源６から転写ローラ３に印加され
る電圧が高いので、記録紙の裏面が転写ローラ３の表面
との間の放電によって帯電してしまう。その結果、記録
紙２はガイド板５との接近による激しい放電によって未
定着の不安定なトナー像が乱れてしまう可能性がある。
したがって、この放電を防ぐために、転写後に記録紙２
の裏面を除電する除電手段を必要としていた。Further, since the voltage applied from the power source 6 to the transfer roller 3 is high, the back surface of the recording paper is charged by the discharge between the front surface of the transfer roller 3 and the recording paper. As a result, the unfixed and unstable toner image may be disturbed on the recording paper 2 due to the intense discharge due to the approach to the guide plate 5.
Therefore, in order to prevent this discharge, the recording paper 2 is
There was a need for a charge removing means for removing the charge on the back surface of the.

【００１１】また、上述した図１１に示す転写装置で
は、転写搬送ベルト１１として絶縁性ベルトを用いた場
合には電源１５からコロナ帯電器１４に印加される電圧
が大きくなり、消費電力の増加や不要な放電によるノイ
ズの発生、電源１５の大型化といった不具合が生ずる。
また、転写搬送ベルト１１として中抵抗または低抵抗の
ベルトを用いた場合には、電流が転写ニップ部以外に転
写搬送ベルト１１の周方向へ流れてしまい、消費電力の
増加を招いてしまう。また、感光体１７と転写搬送ベル
ト１１との間で不要な放電が発生し、転写チリの原因と
なるなどの不具合が発生してしまう。In the transfer device shown in FIG. 11 described above, when an insulating belt is used as the transfer / conveying belt 11, the voltage applied from the power source 15 to the corona charger 14 becomes large, and the power consumption increases. Problems such as generation of noise due to unnecessary discharge and upsizing of the power supply 15 occur.
Further, when a medium resistance belt or a low resistance belt is used as the transfer / conveyance belt 11, a current flows in the circumferential direction of the transfer / conveyance belt 11 other than the transfer nip portion, resulting in an increase in power consumption. Further, unnecessary discharge occurs between the photoconductor 17 and the transfer / conveyance belt 11, which causes a problem such as transfer dust.

【００１２】本発明は、転写ニップ部においてのみ転写
を行うことができて高画質化を図ることができ、転写電
界を作り出すための印加電圧を小さくすることができ、
不要な放電を防止することができる転写装置を提供する
ことを目的とする。According to the present invention, the transfer can be performed only in the transfer nip portion, the image quality can be improved, and the applied voltage for generating the transfer electric field can be reduced.
It is an object of the present invention to provide a transfer device capable of preventing unnecessary discharge.

【００１３】[0013]

【課題を解決するための手段】上記目的を達成するた
め、請求項１記載の発明は、静電像担持体に対して均一
な初期帯電を行った後に部分的に初期帯電を消去して静
電荷のパターンを形成し、該静電荷のパターンをトナー
により現像して記録紙あるいは中間転写体に転写する画
像形成装置の転写装置において、前記静電像担持体に押
圧されて前記トナーの帯電極性とは逆の極性の電圧が印
加され、前記静電像担持体との間に介在する前記記録紙
あるいは前記中間転写体に前記静電像担持体からトナー
を転写させる加圧導電性部材を備えたものである。In order to achieve the above object, the invention according to claim 1 statically erases the static charge by partially initializing the static charge on the electrostatic image bearing member. In a transfer device of an image forming apparatus that forms a pattern of electric charges, develops the pattern of electrostatic charges with toner, and transfers the electrostatic charge pattern onto recording paper or an intermediate transfer member, the charging polarity of the toner is pressed by the electrostatic image carrier. And a pressure conductive member that is applied with a voltage having a polarity opposite to that of the above and transfers the toner from the electrostatic image carrier to the recording paper or the intermediate transfer medium that is interposed between the voltage and the electrostatic image carrier. It is a thing.

【００１４】請求項２記載の発明は、請求項１記載の転
写装置において、前記加圧導電性部材は金属ローラの表
面に設けてローラ形状としたものである。According to a second aspect of the present invention, in the transfer device according to the first aspect, the pressure conductive member is provided on the surface of a metal roller and has a roller shape.

【００１５】請求項３記載の発明は、静電像担持体に対
して均一な初期帯電を行った後に部分的に初期帯電を消
去して静電荷のパターンを形成し、該静電荷のパターン
をトナーにより現像して記録紙に転写する画像形成装置
の転写装置において、前記記録紙を搬送する転写搬送ベ
ルトと、この転写搬送ベルトの裏側に前記記録紙が前記
静電像担持体と接触する位置付近で接触し前記トナーの
帯電極性とは逆の極性の電圧が印加されて前記静電像担
持体から前記記録紙へトナーを転写させる加圧導電性部
材を備えたものである。According to a third aspect of the present invention, after the initial charging is uniformly performed on the electrostatic image bearing member, the initial charging is partially erased to form an electrostatic charge pattern, and the electrostatic charge pattern is formed. In a transfer device of an image forming apparatus that develops with toner and transfers it to recording paper, a transfer conveyor belt for conveying the recording paper, and a position on the back side of the transfer conveyor belt where the recording paper comes into contact with the electrostatic image carrier. It is provided with a pressure conductive member which comes into contact with in the vicinity and is applied with a voltage having a polarity opposite to the charging polarity of the toner to transfer the toner from the electrostatic image carrier to the recording paper.

【００１６】請求項４記載の発明は、静電像担持体に対
して均一な初期帯電を行った後に部分的に初期帯電を消
去して静電荷のパターンを形成し、該静電荷のパターン
をトナーにより現像して記録紙に転写する画像形成装置
の転写装置において、加圧導電性部材で構成され前記記
録紙を搬送する転写搬送ベルトと、この転写搬送ベルト
の裏側に前記記録紙が前記静電像担持体と接触する位置
付近で接触し前記トナーの帯電極性とは逆の極性の電圧
が印加されて前記静電像担持体から前記記録紙へトナー
を転写させる加圧部材とを備えたものである。According to a fourth aspect of the present invention, after the initial charging is uniformly performed on the electrostatic image bearing member, the initial charging is partially erased to form an electrostatic charge pattern, and the electrostatic charge pattern is formed. In a transfer device of an image forming apparatus that develops with toner and transfers the recording paper to a recording paper, a transfer conveyor belt configured by a pressure conductive member for conveying the recording paper, and the recording paper on the back side of the transfer conveyor belt. And a pressing member that is brought into contact with the electrophotographic image carrier in the vicinity thereof and is applied with a voltage having a polarity opposite to the charging polarity of the toner to transfer the toner from the electrostatic image carrier to the recording paper. It is a thing.

【００１７】請求項５記載の発明は、請求項１、３また
は４記載の転写装置において、前記画像形成装置の非画
像形成時に当該転写装置を前記静電像担持体に対して非
接触状態とする手段を備えたものである。According to a fifth aspect of the present invention, in the transfer device according to the first, third or fourth aspect, the transfer device is brought into a non-contact state with the electrostatic image carrier at the time of non-image formation of the image forming apparatus. It is equipped with a means to do.

【００１８】請求項６記載の発明は、請求項１、３また
は４記載の転写装置において、当該転写装置の前記静電
像担持体との接触面側に高抵抗層を設けたものである。According to a sixth aspect of the present invention, in the transfer device according to the first, third or fourth aspect, a high resistance layer is provided on the contact surface side of the transfer device with the electrostatic image carrier.

【００１９】請求項７記載の発明は、静電像担持体に対
して均一な初期帯電を行った後に部分的に初期帯電を消
去して静電荷のパターンを形成し、該静電荷のパターン
をトナーにより現像して記録紙に転写する画像形成装置
の転写装置において、前記記録紙を搬送する感圧導電性
ベルトと、この感圧導電性ベルトの裏側を転写位置付近
で押圧しバイアスが印加されて転写電界を形成させるこ
とにより前記静電像担持体上のトナーを前記記録紙に転
写せしめる転写部材とを備え、この転写部材を弾性層を
含むローラ構造としたものである。According to a seventh aspect of the present invention, after the initial charging is uniformly performed on the electrostatic image bearing member, the initial charging is partially erased to form an electrostatic charge pattern, and the electrostatic charge pattern is formed. In a transfer device of an image forming apparatus that develops with toner and transfers it to recording paper, a pressure-sensitive conductive belt that conveys the recording paper and the back side of the pressure-sensitive conductive belt are pressed near a transfer position to apply a bias. A transfer member for transferring the toner on the electrostatic image carrier to the recording paper by forming a transfer electric field by the transfer member, and the transfer member has a roller structure including an elastic layer.

【００２０】請求項８記載の発明は、静電像担持体に対
して均一な初期帯電を行った後に部分的に初期帯電を消
去して静電荷のパターンを形成し、該静電荷のパターン
をトナーにより現像して記録紙に転写する画像形成装置
の転写装置において、前記記録紙を搬送する感圧導電性
ベルトと、この感圧導電性ベルトの裏側を転写位置付近
で押圧しバイアスが印加されて転写電界を形成させるこ
とにより前記静電像担持体上のトナーを前記記録紙に転
写せしめる転写部材とを備え、前記静電像担持体と前記
感圧導電性ベルトが形成するニップ幅をｔ１、前記感圧
導電性ベルトと前記転写部材が形成するニップ幅をｔ２
としたとき、ｔ１＞ｔ２としたものである。According to the present invention, the electrostatic image bearing member is uniformly pre-charged, and then the initial charging is partially erased to form an electrostatic charge pattern, and the electrostatic charge pattern is formed. In a transfer device of an image forming apparatus that develops with toner and transfers it to recording paper, a pressure-sensitive conductive belt that conveys the recording paper and the back side of the pressure-sensitive conductive belt are pressed near a transfer position to apply a bias. A transfer member for transferring the toner on the electrostatic image carrier to the recording paper by forming a transfer electric field by the transfer member, and the nip width formed by the electrostatic image carrier and the pressure-sensitive conductive belt is t1. , The nip width formed by the pressure-sensitive conductive belt and the transfer member is t2.
Then, t1> t2.

【００２１】[0021]

【発明の実施の形態】図１は本発明の第１実施形態例乃
至第４実施形態例の基本構成を示す。この実施形態例は
複写機、ファクシミリ、プリンタ等の画像形成装置にお
ける転写装置の例である。この実施形態例を用いた画像
形成装置は、例えば電子写真技術を利用した画像形成装
置であって、駆動部により回転駆動されるドラム状の感
光体からなる静電像担持体２１に対して、帯電手段によ
り均一な初期帯電を行った後に露光手段にて画像信号に
応じて変調された光信号の照射による画像露光を行うこ
とで初期帯電を部分的に消去して静電荷のパターンを形
成し、該静電荷のパターンを現像手段でトナーにより現
像してトナー像とし、このトナー像を本実施形態例の転
写装置２２により転写電界で記録紙２３に転写し、定着
手段により記録紙２３上のトナー像２４を定着させる。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the basic construction of the first to fourth embodiment examples of the present invention. This embodiment is an example of a transfer device in an image forming apparatus such as a copying machine, a facsimile, and a printer. An image forming apparatus using this embodiment is an image forming apparatus using, for example, an electrophotographic technique, and an electrostatic image carrier 21 composed of a drum-shaped photoconductor that is rotationally driven by a drive unit is used. After performing uniform initial charging by the charging means, the exposure means performs image exposure by irradiating an optical signal modulated according to the image signal to partially erase the initial charge and form a static charge pattern. The electrostatic charge pattern is developed with toner by developing means to form a toner image, and the toner image is transferred onto the recording paper 23 by a transfer electric field by the transfer device 22 of the present embodiment, and is fixed on the recording paper 23 by the fixing means. The toner image 24 is fixed.

【００２２】本実施形態例においては、加圧導電性部材
２５は加圧部材２６により感光体２１に押し付けられて
転写位置（もしくはその付近）で感光体２１に接触し、
現像手段から感光体２１へ付着されるトナーの帯電極性
とは逆の極性の電圧が電源２７から加圧部材２６に印加
されて転写電界が加圧導電性部材２５と感光体２１との
間に形成される。加圧導電性部材２５は、導電性金属粒
子やカーボンブラックが均一に分散したシリコーンゴム
など、圧力が加えられることにより大きな抵抗変化が生
ずるものである。記録紙２３は、感光体２１と加圧導電
性部材２５との間を通過する時に転写電界により感光体
２１上のトナー像が記録紙２３に転写される。In this embodiment, the pressure conductive member 25 is pressed against the photoconductor 21 by the pressure member 26 and comes into contact with the photoconductor 21 at the transfer position (or in the vicinity thereof).
A voltage having a polarity opposite to the charging polarity of the toner adhered to the photoconductor 21 from the developing means is applied from the power source 27 to the pressure member 26 so that a transfer electric field is applied between the pressure conductive member 25 and the photoconductor 21. It is formed. The pressure conductive member 25 is a member such as a silicone rubber in which conductive metal particles and carbon black are uniformly dispersed, which causes a large resistance change when pressure is applied. When the recording paper 23 passes between the photoconductor 21 and the pressure conductive member 25, the toner image on the photoconductor 21 is transferred to the recording paper 23 by the transfer electric field.

【００２３】図２は感光体２１と加圧導電性部材２５と
により形成される転写ニップ部を拡大して示す。転写ニ
ップ部における感光体２１と加圧導電性部材２５との間
の圧力の分布は、感光体２１と加圧部材２６の形状によ
って決まり、図３に示すような分布になる。つまり、転
写ニップ部における感光体２１と加圧導電性部材２５と
の間の圧力は、転写ニップ部の中央ａが最も大きくな
り、その両側ｂ、ｃが小さくなる。FIG. 2 is an enlarged view of a transfer nip portion formed by the photoconductor 21 and the pressure conductive member 25. The pressure distribution between the photoconductor 21 and the pressure conductive member 25 in the transfer nip portion is determined by the shapes of the photoconductor 21 and the pressure member 26, and has a distribution as shown in FIG. In other words, the pressure between the photoconductor 21 and the pressure conductive member 25 in the transfer nip portion becomes maximum at the center a of the transfer nip portion and becomes smaller on both sides b and c thereof.

【００２４】したがって、加圧導電性部材２５の抵抗分
布は感光体２１と加圧導電性部材２５との間の圧力に応
じて図４に示すように転写ニップ部の中央ａが最も小さ
くなり、その両側ｂ、ｃが大きくなる。このため、転写
電界は転写ニップ部の中央ａに集中し、感光体２１と記
録紙２３との非接触部でトナーが転写されることはな
い。したがって、画質が劣化することなく転写が行われ
る。また、転写電界が転写ニップ部の中央ａに集中する
ので、加圧導電性部材２５から記録紙２３の裏面への放
電による記録紙２３の裏面の帯電を回避することがで
き、オゾンの発生もない。更に、加圧導電性部材２５
は、転写ニップ部で抵抗が小さくなるので、電源２７に
よる印加電圧が小さくてもよい。Therefore, the resistance distribution of the pressure conductive member 25 becomes the smallest at the center a of the transfer nip portion according to the pressure between the photosensitive member 21 and the pressure conductive member 25, as shown in FIG. Both sides b and c become large. Therefore, the transfer electric field concentrates on the center a of the transfer nip portion, and the toner is not transferred at the non-contact portion between the photoconductor 21 and the recording paper 23. Therefore, the transfer is performed without deteriorating the image quality. In addition, since the transfer electric field is concentrated on the center a of the transfer nip portion, it is possible to avoid charging of the back surface of the recording paper 23 due to discharge from the pressure conductive member 25 to the back surface of the recording paper 23, and ozone is also generated. Absent. Further, the pressure conductive member 25
Since the resistance at the transfer nip portion becomes small, the voltage applied by the power supply 27 may be small.

【００２５】図５は本発明の第１実施形態例を示す。こ
の第１実施形態例は、請求項１、２、５記載の発明の実
施形態例である。第１実施形態例では、図１に示した実
施形態例において、転写ローラ２８は芯金２８ａの外周
に加圧導電性部材２５を設けた構成とした。転写ローラ
２８の芯金２８ａには現像手段から感光体２１へ付着さ
れるトナーの帯電極性とは逆の極性の転写バイアス電圧
が電源２７から印加され、転写ローラ２８と感光体２１
との間に転写電界が形成される。記録紙２３は、転写ロ
ーラ２８と感光体２１との間を通過する時に転写電界に
より感光体２１上のトナー像２４が転写され、ガイド板
２９により案内されて図示しない定着装置によりトナー
像が定着される。FIG. 5 shows a first embodiment of the present invention. The first embodiment is an embodiment of the invention described in claims 1, 2, and 5. In the first embodiment, in the embodiment shown in FIG. 1, the transfer roller 28 has a structure in which the pressure conductive member 25 is provided on the outer periphery of the cored bar 28a. A transfer bias voltage having a polarity opposite to the charging polarity of the toner attached to the photoconductor 21 from the developing means is applied to the core metal 28a of the transfer roller 28 from the power source 27, and the transfer roller 28 and the photoconductor 21 are charged.
A transfer electric field is formed between and. When the recording paper 23 passes between the transfer roller 28 and the photoconductor 21, the toner image 24 on the photoconductor 21 is transferred by the transfer electric field, is guided by the guide plate 29, and the toner image is fixed by a fixing device (not shown). To be done.

【００２６】加圧導電性部材２５としては、横浜ゴム
（株）製のＹＣＲＴＭ３０００を用いた。また、転写ロ
ーラ２８は加圧手段により約１［ｋｇｆ］の力で静電像
担持体としての感光体２１に圧接した。この圧接力の最
適値は、転写ローラ２８の硬度や感光体２１の直径、転
写ローラ２８の直径等によって異なるが、本実施形態例
の場合にはφ６０の感光体２１とφ１２の転写ローラ２
８を用いて約１［ｋｇｆ］の力で転写ローラ２８を感光
体２１に圧接したところ、約１［ｍｍ］の転写ニップ幅
が得られた。良好に転写を行うためには、転写ニップ幅
が０．２［ｍｍ］以上あることが好ましい。その理由
は、転写ニップ幅を０．２［ｍｍ］以下にした場合に
は、本装置２２の振動等で転写ローラ２８と感光体２１
との接触状態が不安定になることにある。As the pressure conductive member 25, YCRTM3000 manufactured by Yokohama Rubber Co., Ltd. was used. Further, the transfer roller 28 was pressed against the photosensitive member 21 as an electrostatic image bearing member with a force of about 1 [kgf] by the pressing means. The optimum value of the pressure contact force varies depending on the hardness of the transfer roller 28, the diameter of the photoconductor 21, the diameter of the transfer roller 28, etc., but in the present embodiment, the photoconductor 21 of φ60 and the transfer roller 2 of φ12 are used.
When the transfer roller 28 was pressed against the photoconductor 21 with a force of about 1 [kgf] using No. 8, a transfer nip width of about 1 [mm] was obtained. For good transfer, the transfer nip width is preferably 0.2 [mm] or more. The reason is that when the transfer nip width is set to 0.2 [mm] or less, the transfer roller 28 and the photoconductor 21 are damaged by vibration of the apparatus 22 or the like.
The contact state with is unstable.

【００２７】転写電界を生成するために、７００［Ｖ］
の電圧を電源２７から芯金２８ａに印加したところ、画
質劣化がなく転写ができた。また、オゾンはほとんど発
生しなかった。しかし、高温高湿環境下にて本装置２２
を停止状態で２週間放置したところ、感光体２１に加圧
導電性部材２５の材料がしみ出して感光体２１の表面が
汚染されてしまうという不具合が生じた。In order to generate a transfer electric field, 700 [V]
When the voltage of 2 was applied from the power source 27 to the cored bar 28a, transfer was possible without deterioration of image quality. Moreover, almost no ozone was generated. However, under the high temperature and high humidity environment, the device 22
When the sheet was left standing for 2 weeks in a stopped state, the material of the pressure conductive member 25 exudes to the photoconductor 21 and the surface of the photoconductor 21 is contaminated.

【００２８】そこで、本装置２２の運転時のみ転写ロー
ラ２８を感光体２１に接触させ、本装置２２の非運転時
には転写ローラ２８を感光体２１に対して非接触状態と
する転写ローラ接離機構を設けたところ、感光体２１が
汚染してしまうという不具合がなくなった。通常の環境
であれば、本装置２２を長時間放置しても問題は生じな
いので、特に転写ローラ接離機構を設けなくてもよい
が、上述した理由により転写ローラ接離機構を設けた方
が好ましい。この第１実施形態例は感光体２１から記録
紙２３にトナー像を転写する例であるが、記録紙ではな
くて中間転写体に感光体２１からトナー像を転写する場
合には請求項１、２記載の発明を同様に適用することが
可能である。Therefore, a transfer roller contact / separation mechanism that brings the transfer roller 28 into contact with the photoconductor 21 only when the apparatus 22 is in operation, and brings the transfer roller 28 into non-contact with the photoconductor 21 when the apparatus 22 is not in operation. However, the problem that the photoconductor 21 is contaminated disappears. In a normal environment, there is no problem even if the apparatus 22 is left for a long time. Therefore, it is not necessary to provide the transfer roller contact / separation mechanism. However, the transfer roller contact / separation mechanism is provided for the above reason. Is preferred. In the first embodiment, the toner image is transferred from the photoconductor 21 to the recording paper 23. However, when the toner image is transferred from the photoconductor 21 to the intermediate transfer body instead of the recording paper, the first embodiment The invention described in 2 can be similarly applied.

【００２９】このように、第１実施形態例は、請求項１
記載の発明の実施形態例であって、静電像担持体として
の感光体２１に対して均一な初期帯電を行った後に部分
的に初期帯電を消去して静電荷のパターンを形成し、該
静電荷のパターンをトナーにより現像して記録紙（ある
いは中間転写体）に転写する画像形成装置の転写装置に
おいて、静電像担持体２１に押し付けられて前記トナー
の帯電極性とは逆の極性の電圧が印加され、静電像担持
体２１との間に介在する記録紙２３（あるいは中間転写
体）に静電像担持体２１からトナーを転写させる加圧導
電性部材２５を備えたので、転写電界を転写ニップ部に
集中して発生させることができて転写ニップ部において
のみ転写を行うことができ、高画質を図ることができ
る。また、転写ニップ部においては抵抗が小さいので、
転写電界を作り出すための印加電圧を小さくすることが
できる。As described above, the first embodiment is characterized by claim 1.
In the embodiment of the invention described, the photosensitive body 21 as an electrostatic image carrier is subjected to uniform initial charging, and then the initial charging is partially erased to form an electrostatic charge pattern. In a transfer device of an image forming apparatus that develops an electrostatic charge pattern with a toner and transfers the electrostatic charge pattern onto a recording paper (or an intermediate transfer body), the electrostatic charge pattern is pressed against an electrostatic image carrier 21 and has a polarity opposite to that of the toner. Since a voltage-applied conductive member 25 for transferring the toner from the electrostatic image carrier 21 to the recording paper 23 (or intermediate transfer member) interposed between the electrostatic image carrier 21 and the electrostatic image carrier 21, the transfer is performed. The electric field can be concentratedly generated in the transfer nip portion, and the transfer can be performed only in the transfer nip portion, so that high image quality can be achieved. Also, since the resistance at the transfer nip is small,
The applied voltage for creating the transfer electric field can be reduced.

【００３０】また、第１実施形態例は、請求項２記載の
発明の実施形態例であって、請求項１記載の転写装置に
おいて、加圧導電性部材２５は金属ローラ２８ａの表面
に設けてローラ形状としたので、構成が簡易で、感光体
２１への負荷が大きくならない。Further, the first embodiment is an embodiment of the invention described in claim 2, and in the transfer device described in claim 1, the pressure conductive member 25 is provided on the surface of the metal roller 28a. Since the roller shape is adopted, the structure is simple and the load on the photoconductor 21 does not increase.

【００３１】また、第１実施形態例は、請求項５記載の
発明の実施形態例であって、請求項１記載の転写装置に
おいて、画像形成装置の非画像形成時に当該転写装置を
静電像担持体２１に対して非接触状態とする手段として
の転写ローラ接離機構を備えたので、加圧導電性部材２
５の材料が静電像担持体２１に溶着することがなくな
り、耐久性を向上させることができる。The first embodiment is an embodiment of the invention described in claim 5, and in the transfer device according to claim 1, when the image forming apparatus is not forming an image, the transfer device is electrostatically imaged. Since the transfer roller contact / separation mechanism is provided as means for bringing the carrier 21 into a non-contact state, the pressure conductive member 2
The material of No. 5 will not be welded to the electrostatic image carrier 21, and the durability can be improved.

【００３２】図６は本発明の第２実施形態例を示す。こ
の第２実施形態例は請求項３記載の発明の実施形態例で
ある。第２実施形態例では、図１に示した実施形態例に
おいて、転写搬送ベルト３０は駆動ローラ３１とテンシ
ョンローラ３２に張架されて駆動ローラ３１により回転
駆動される。転写ローラ２８は第１実施形態例と同様に
芯金２８ａの外周に加圧導電性部材２５を設けて構成さ
れる。FIG. 6 shows a second embodiment of the present invention. The second embodiment is an embodiment of the invention according to claim 3. In the second embodiment, in the embodiment shown in FIG. 1, the transfer / conveyance belt 30 is stretched between a driving roller 31 and a tension roller 32 and is rotationally driven by the driving roller 31. The transfer roller 28 is configured by providing the pressure conductive member 25 on the outer periphery of the cored bar 28a, as in the first embodiment.

【００３３】加圧導電性部材２５は転写搬送ベルト３０
の裏側に対して記録紙２３と感光体２１とが接触する位
置（もしくはその付近）で接触し、トナーの帯電極性と
は逆の極性の電圧が電源２７から印加されて感光体２１
と転写搬送ベルト３０との間に転写電界が形成される。
記録紙２３は、転写搬送ベルト３０により静電的に吸着
されて搬送され、感光体２１と転写搬送ベルト３０とに
より形成される転写ニップ部を通過する時に感光体２１
上のトナー像２４が転写される。The pressure conductive member 25 is the transfer / transport belt 30.
The recording paper 23 and the photoconductor 21 make contact with the back side of the photoconductor 21 at a position (or in the vicinity thereof), and a voltage having a polarity opposite to the charging polarity of the toner is applied from the power supply 27 to the photoconductor 21.
A transfer electric field is formed between the transfer transfer belt 30 and the transfer transfer belt 30.
The recording paper 23 is electrostatically adsorbed and conveyed by the transfer / conveyance belt 30, and when the recording paper 23 passes through a transfer nip portion formed by the photoreceptor 21 and the transfer / conveyor belt 30,
The upper toner image 24 is transferred.

【００３４】転写搬送ベルト３０は、厚さ５００［μ
ｍ］のエピクロルヒドリンゴム製であり、転写ローラ２
８は加圧手段により約１［ｋｇｆ］の力で転写搬送ベル
ト３０を介してφ６０の感光体２１に押し付けられる。
その結果、感光体２１と転写搬送ベルト３０とにより形
成される転写ニップ部の幅は約２［ｍｍ］であった。こ
の第２実施形態例では、記録紙２３を転写搬送ベルト３
０により静電的に吸着して搬送するので、第１実施形態
例よりも高速かつ安定に記録紙を搬送できた。The transfer / transport belt 30 has a thickness of 500 [μ
m] made of epichlorohydrin rubber, the transfer roller 2
The pressing unit 8 is pressed against the photosensitive member 21 having a diameter of 60 via the transfer / conveying belt 30 with a force of about 1 [kgf] by the pressing unit.
As a result, the width of the transfer nip portion formed by the photoconductor 21 and the transfer conveyance belt 30 was about 2 [mm]. In the second embodiment, the recording paper 23 is transferred onto the transfer / transport belt 3
Since 0 is electrostatically adsorbed and conveyed, the recording sheet can be conveyed at a higher speed and more stably than in the first embodiment.

【００３５】記録紙２３の線速が１００［ｍｍ／ｓ］の
時に、転写ローラ２８の芯金２８ａには電源２７から約
２［ｋＶ］の電圧を印加したところ、良好な転写性能が
得られた。しかし、記録紙２３の線速を１５０［ｍｍ／
ｓ］にしたところ、感光体２１にトナーが残ってしまっ
た。そこで、転写ローラ２８の芯金２８ａに電源２７か
ら印加する電圧を３［ｋＶ］としたところ、良好な転写
結果が得られた。この記録紙２３の速い線速に対して
は、転写ローラ２８の芯金２８ａに電源２７から印加す
る電圧が２［ｋＶ］のままであっても、転写ニップ部の
幅が３［ｍｍ］になるように上記加圧手段の加圧力を調
整することによって良好に対処できた。When the linear velocity of the recording paper 23 is 100 [mm / s], a voltage of about 2 [kV] is applied to the core metal 28a of the transfer roller 28 from the power source 27, and good transfer performance is obtained. It was However, the linear velocity of the recording paper 23 is 150 [mm /
[s], the toner remained on the photoconductor 21. Therefore, when the voltage applied from the power source 27 to the cored bar 28a of the transfer roller 28 was set to 3 [kV], a good transfer result was obtained. With respect to the high linear velocity of the recording paper 23, even if the voltage applied from the power source 27 to the cored bar 28a of the transfer roller 28 remains 2 [kV], the width of the transfer nip portion becomes 3 [mm]. It was possible to satisfactorily cope with this by adjusting the pressure applied by the above-mentioned pressurizing means.

【００３６】この第２実施形態例は、請求項３記載の発
明の実施形態例であって、静電像担持体としての感光体
２１に対して均一な初期帯電を行った後に部分的に初期
帯電を消去して静電荷のパターンを形成し、該静電荷の
パターンをトナーにより現像して記録紙２３に転写する
画像形成装置の転写装置において、記録紙２３を搬送す
る転写搬送ベルト３０と、この転写搬送ベルト３０の裏
側に記録紙２３が静電像担持体２１と接触する位置付近
で接触しトナーの帯電極性とは逆の極性の電圧が印加さ
れて静電像担持体２１から記録紙２３へトナーを転写さ
せる加圧導電性部材２５を備えたので、記録紙の搬送が
安定化し、記録紙の高速搬送が可能となる。また、転写
が静電像担持体と記録紙とのニップ部でのみ行われ、画
質劣化がない。The second embodiment is an embodiment of the present invention as set forth in claim 3, and is partially initialized after uniform initial charging is performed on the photoconductor 21 as an electrostatic image carrier. In a transfer device of an image forming apparatus that erases electric charge to form an electrostatic charge pattern, develops the electrostatic charge pattern with toner, and transfers the electrostatic charge pattern onto the recording paper 23, a transfer conveyor belt 30 that conveys the recording paper 23, The recording paper 23 comes into contact with the back side of the transfer / transport belt 30 in the vicinity of a position where the recording paper 23 comes into contact with the electrostatic image carrier 21, and a voltage having a polarity opposite to the charging polarity of the toner is applied to the recording paper 23 from the electrostatic image carrier 21. Since the pressurizing conductive member 25 for transferring the toner to the recording sheet 23 is provided, the conveyance of the recording paper is stabilized and the recording paper can be conveyed at a high speed. Further, the transfer is performed only at the nip portion between the electrostatic image carrier and the recording paper, and the image quality is not deteriorated.

【００３７】なお、第２実施形態例では、転写ローラ２
８を用いたが、転写搬送ベルト３０の駆動力が十分に大
きい場合には、例えば図７に示すように加圧導電性部材
２５をローラ形状にせず、スプリング等の加圧手段３３
で加圧導電性部材２５を転写搬送ベルト３０を介して感
光体２１に押し付け、加圧導電性部材２５に電源２７か
らトナーの帯電極性とは逆の極性の電圧を印加するよう
に構成することも可能である。この構成は、簡易である
が、転写搬送ベルト３０や加圧導電性部材２５が摩耗し
てしまう点で好ましくない。In the second embodiment, the transfer roller 2
However, when the driving force of the transfer / conveying belt 30 is sufficiently large, the pressing conductive member 25 is not formed into a roller shape as shown in FIG.
The pressing conductive member 25 is pressed against the photoconductor 21 via the transfer / conveying belt 30, and a voltage having a polarity opposite to the charging polarity of the toner is applied from the power supply 27 to the pressing conductive member 25. Is also possible. Although this structure is simple, it is not preferable because the transfer / conveying belt 30 and the pressure conductive member 25 are worn.

【００３８】また、本発明の第３実施形態例は、請求項
５記載の発明の実施形態例であって、上記第２実施形態
例において、本装置２２の運転時のみ転写ローラ２８を
転写搬送ベルト３０を介して感光体２１に押し付け、本
装置２２の非運転時にはその押し付けを解除することで
転写ローラ２８を転写搬送ベルト３０に対して非接触状
態として転写搬送ベルト３０を感光体２１に対して非接
触状態とする接離機構を設けたものである。この第３実
施形態例では、感光体２１に加圧導電性部材２５の材料
がしみ出して転写搬送ベルト３０や感光体２１が汚染さ
れてしまうという不具合がなくなり、耐久性が向上す
る。The third embodiment of the present invention is an embodiment of the invention described in claim 5, and in the second embodiment, the transfer roller 28 is transferred and conveyed only when the apparatus 22 is in operation. The transfer roller 28 is pressed against the photoconductor 21 via the belt 30, and when the device 22 is not in operation, the pressing is released so that the transfer roller 28 is not in contact with the transfer transport belt 30 and the transfer transport belt 30 is moved against the photoconductor 21. A contacting / separating mechanism is provided to bring them into non-contact state. In the third embodiment, the problem that the material of the pressure conductive member 25 exudes to the photoconductor 21 to contaminate the transfer / transport belt 30 and the photoconductor 21 is eliminated, and the durability is improved.

【００３９】図８は本発明の第４実施形態例を示す。こ
の第４実施形態例は、請求項４、６記載の発明の実施形
態例であり、上記第２実施形態例において、転写搬送ベ
ルト３０の代りに、加圧導電性部材を厚さ１［ｍｍ］の
ベルト状に構成した転写搬送ベルト３４を用い、加圧ロ
ーラ３５を転写搬送ベルト３４の裏側に記録紙２３が感
光体２１と接触する位置（もしくはその付近）で接触さ
せたものである。加圧ローラ３５は転写バイアスを供給
する機能を兼ねていて金属で構成され、電源２７から加
圧ローラ３５にトナーの帯電極性とは逆の極性の電圧が
印加されて感光体２１と転写搬送ベルト３０との間に転
写電界が形成される。FIG. 8 shows a fourth embodiment of the present invention. The fourth embodiment is an embodiment of the invention described in claims 4 and 6, and in the second embodiment, instead of the transfer / conveying belt 30, a pressure conductive member having a thickness of 1 [mm] is used. ], The pressure roller 35 is brought into contact with the back side of the transfer / conveyor belt 34 at the position (or in the vicinity) where the recording paper 23 comes into contact with the photoconductor 21. The pressure roller 35 also has a function of supplying a transfer bias and is made of metal. A voltage having a polarity opposite to the charging polarity of the toner is applied from the power source 27 to the pressure roller 35 to apply the voltage to the photoconductor 21 and the transfer conveyance belt. A transfer electric field is formed between 30 and 30.

【００４０】加圧ローラ３５は電源２７から１．５［ｋ
Ｖ］の電圧が印加され、記録紙２３の線速を１５０［ｍ
ｍ／ｓ］とした。その結果、初期的には良好な転写性能
を得ることができた。しかし、耐久試験を行ったとこ
ろ、感光体２１にピンホールが生じた際に転写ニップ部
で過大な電流が流れ、第４実施形態例を用いたシステム
が停止してしまった。The pressure roller 35 receives 1.5 [k] from the power source 27.
V] is applied and the linear velocity of the recording paper 23 is 150 [m
m / s]. As a result, good transfer performance could be obtained initially. However, as a result of the durability test, when a pinhole was generated in the photoconductor 21, an excessive current flowed in the transfer nip portion, and the system using the fourth embodiment stopped.

【００４１】そこで、表面抵抗が約１０12［Ω／ｃ
ｍ2］、厚さが１０［μｍ］の薄い高抵抗層を転写搬送
ベルト３４の表面に被覆した。その結果、感光体２１に
ピンホールがあっても第４実施形態例を用いたシステム
が停止することがなく、良好に転写を行うことができ
た。また、第４実施形態例では、転写搬送ベルト３４を
加圧導電性部材で構成したことにより、第２実施形態例
よりも低電圧で転写を行うことができた。Therefore, the surface resistance is about 10 12 [Ω / c
m 2 ], and a thin high-resistance layer having a thickness of 10 μm was coated on the surface of the transfer / conveying belt 34. As a result, even if the photoconductor 21 had a pinhole, the system using the fourth embodiment did not stop, and good transfer could be performed. Further, in the fourth embodiment, since the transfer / conveying belt 34 is composed of the pressure conductive member, the transfer can be performed at a lower voltage than that in the second embodiment.

【００４２】このように、第４実施形態例は、請求項４
記載の発明の実施形態例であって、静電像担持体として
の感光体２１に対して均一な初期帯電を行った後に部分
的に初期帯電を消去して静電荷のパターンを形成し、該
静電荷のパターンをトナーにより現像して記録紙２３に
転写する画像形成装置の転写装置において、加圧導電性
部材で構成され記録紙２３を搬送する転写搬送ベルト３
４と、この転写搬送ベルト３４の裏側に記録紙２３が静
電像担持体２１と接触する位置付近で接触しトナーの帯
電極性とは逆の極性の電圧が印加されて静電像担持体２
１から記録紙２３へトナーを転写させる加圧部材として
の加圧ローラ３５とを備えたので、より低い電圧で転写
を行うことができる。As described above, the fourth embodiment is characterized by claim 4.
In the embodiment of the invention described, the photosensitive body 21 as an electrostatic image carrier is subjected to uniform initial charging, and then the initial charging is partially erased to form an electrostatic charge pattern. In a transfer device of an image forming apparatus that develops an electrostatic charge pattern with toner and transfers it to the recording paper 23, a transfer conveyor belt 3 configured by a pressure conductive member to convey the recording paper 23.
4 and the back side of the transfer / conveying belt 34 near the position where the recording paper 23 contacts the electrostatic image carrier 21, and a voltage having a polarity opposite to the charging polarity of the toner is applied to the electrostatic image carrier 2.
Since the pressure roller 35 as a pressure member for transferring the toner from the recording paper 1 to the recording paper 23 is provided, the transfer can be performed at a lower voltage.

【００４３】また、第４実施形態例は、請求項６記載の
発明の実施形態例であって、当該転写装置２２の静電像
担持体２１との接触面側（転写搬送ベルト３４の表面）
に高抵抗層を設けたので、静電像担持体にピンホールが
ある場合にも、過大電流が流れてシステムダウンしたり
転写不良を起こしたりすることがない。Further, the fourth embodiment is an embodiment of the invention described in claim 6, and the contact surface side of the transfer device 22 with the electrostatic image carrier 21 (the surface of the transfer / transport belt 34).
Since the high resistance layer is provided in the above, even if there is a pinhole in the electrostatic image carrier, an excessive current does not flow to cause system down or transfer failure.

【００４４】なお、第４実施形態例において、本装置２
２の運転時のみ転写ローラ３５を転写搬送ベルト３０を
介して感光体２１に押し付け、本装置２２の非運転時に
はその押し付けを解除することで転写ローラ３５を転写
搬送ベルト３０に対して非接触状態として転写搬送ベル
ト３０を感光体２１に対して非接触状態とする接離機構
を設けてもよい。また、上記第１実施形態例や上記第２
実施形態例において、当該転写装置２２の静電像担持体
２１との接触面側（転写ローラ２８、転写搬送ベルト３
０の表面）に高抵抗層を設けるようにしても、静電像担
持体にピンホールがある場合に過大電流が流れてシステ
ムがダウンしたり転写不良を起こしたりすることがなく
なる。In the fourth embodiment, the device 2 is used.
The transfer roller 35 is pressed against the photoconductor 21 via the transfer / transport belt 30 only during the second operation, and is released when the apparatus 22 is not in operation, so that the transfer roller 35 is not in contact with the transfer / transport belt 30. Alternatively, a contact / separation mechanism for bringing the transfer / transport belt 30 into non-contact with the photoconductor 21 may be provided. In addition, the first embodiment and the second embodiment described above.
In the embodiment, the contact surface side of the transfer device 22 with the electrostatic image carrier 21 (transfer roller 28, transfer conveyance belt 3
Even if the high resistance layer is provided on the surface (0), an excessive current will not flow and the system will not go down or a transfer failure will not occur if the electrostatic image carrier has a pinhole.

【００４５】図１２は本発明の第５実施形態例を示す。
この第５実施形態例は、請求項７、８記載の発明の実施
形態例であり、複写機、ファクシミリ、プリンタ等の画
像形成装置における転写装置の例である。この第５実施
形態例を用いた画像形成装置は、例えば電子写真技術を
利用した画像形成装置であって、駆動部により回転駆動
されるドラム状の感光体からなる静電像担持体４１に対
して、帯電手段により均一な初期帯電を行った後に露光
手段にて画像信号に応じて変調された光信号の照射によ
る画像露光を行うことで初期帯電を部分的に消去して静
電荷のパターンを形成し、該静電荷のパターンを現像手
段でトナーにより現像してトナー像とし、このトナー像
を本実施形態例の転写装置４２により転写電界で記録紙
４３に転写し、定着手段により記録紙４３上のトナー像
を定着させる。FIG. 12 shows a fifth embodiment of the present invention.
The fifth embodiment is an embodiment of the invention described in claims 7 and 8 and is an example of a transfer device in an image forming apparatus such as a copying machine, a facsimile, or a printer. The image forming apparatus using the fifth embodiment is an image forming apparatus using, for example, an electrophotographic technique, and an electrostatic image carrier 41 composed of a drum-shaped photoconductor that is rotationally driven by a drive unit is used. Then, the charging unit uniformly performs initial charging, and then the exposing unit performs image exposure by irradiating an optical signal modulated according to the image signal, thereby partially erasing the initial charging to form an electrostatic charge pattern. The electrostatic charge pattern is formed by a developing means with a toner to form a toner image. The toner image is transferred to a recording paper 43 by a transfer electric field by the transfer device 42 of the present embodiment, and is fixed by the fixing means. Fix the upper toner image.

【００４６】本実施形態例においては、転写搬送ベルト
４４は駆動ローラ４５とテンションローラ４６に張架さ
れて駆動ローラ４５により回転駆動される。この転写搬
送ベルト４４は感圧導電性材料で形成された感圧導電性
ベルトである。感圧導電性材料とは、通常は中〜高抵抗
材料であるが、厚さ方向に圧力を加えると、その方向の
電気抵抗が低下して導電性を示すものである。In the present embodiment, the transfer / conveying belt 44 is stretched between the driving roller 45 and the tension roller 46 and is rotationally driven by the driving roller 45. The transfer / transport belt 44 is a pressure-sensitive conductive belt made of a pressure-sensitive conductive material. The pressure-sensitive conductive material is usually a medium to high resistance material, but when pressure is applied in the thickness direction, the electrical resistance in that direction decreases and the material exhibits conductivity.

【００４７】転写部材４７は図示しないバネ等の弾性体
からなる加圧手段による加圧で感圧導電性ベルト４４の
裏側を転写位置（もしくはその付近）で感光体４１へ押
圧し、上記現像手段により感光体４１上に付着されるト
ナーの帯電極性と逆極性の転写バイアスが電源４８から
転写部材４７に印加されて転写電界が感光体４１と感圧
導電性ベルト４４との間に形成される。記録紙４３は感
光体４１と感圧導電性ベルト４４との間を通過する時に
転写電界により感光体４１上のトナーが転写される。The transfer member 47 presses the back side of the pressure-sensitive conductive belt 44 to the photoconductor 41 at the transfer position (or in the vicinity thereof) by applying pressure by an unillustrated elastic member such as a spring, and the above-mentioned developing means. As a result, a transfer bias having a polarity opposite to the charging polarity of the toner deposited on the photoconductor 41 is applied from the power source 48 to the transfer member 47, and a transfer electric field is formed between the photoconductor 41 and the pressure-sensitive conductive belt 44. . When the recording paper 43 passes between the photoconductor 41 and the pressure-sensitive conductive belt 44, the toner on the photoconductor 41 is transferred by the transfer electric field.

【００４８】転写部材４７はローラ形状のものを用いて
いる。この転写部材４７は、必ずしもローラ形状である
必要はないが、感圧導電性ベルト４４との摩擦や密着性
の点からローラ形状が好ましい。転写部材４７は、感圧
導電性ベルト４４との密着性をさらに挙げるために、多
層構造とし、芯金４７ａの上に少なくとも１つの弾性層
４７ｂを設けてある。The transfer member 47 has a roller shape. The transfer member 47 does not necessarily have a roller shape, but a roller shape is preferable in terms of friction and adhesion with the pressure-sensitive conductive belt 44. The transfer member 47 has a multi-layer structure in order to further improve the adhesiveness to the pressure-sensitive conductive belt 44, and at least one elastic layer 47b is provided on the cored bar 47a.

【００４９】この弾性層４７ｂは、適宜軟化剤が添加さ
れ、硬度（ＪＩＳ−Ａ）で１０〜４０のものが理想的で
ある。また、弾性層４７ｂの抵抗は、低抵抗であるほど
効率がよいが、転写バイアスで転写電界を調整すること
が可能であるため、中抵抗であってもよい。転写部材４
７の表面には、感圧導電性ベルト４４との摩耗を避ける
ために、厚さ５μｍ以上の保護層を設けてもよい。この
保護層は、ナイロンやウレタンゴム等でよい。Ideally, the elastic layer 47b has a hardness (JIS-A) of 10 to 40 to which a softening agent is appropriately added. Further, the resistance of the elastic layer 47b is more efficient as the resistance is lower, but may be medium resistance because the transfer electric field can be adjusted by the transfer bias. Transfer member 4
A protective layer having a thickness of 5 μm or more may be provided on the surface of 7 in order to avoid abrasion with the pressure-sensitive conductive belt 44. This protective layer may be nylon, urethane rubber or the like.

【００５０】感圧導電性ベルト４４は、圧力が加わらな
いときはできるだけ高抵抗であり、圧力が加わると低抵
抗になるゴム材料等が好ましい。このようなゴム材料
は、例えばシリコーンゴムに導電性金属粒子を混合する
ことによって形成される。また、応答性が良く、反復加
圧に対しての劣化の少ない感圧導電性材料を形成するに
は、シリコーンゴムに架橋材、架橋触媒を加え、さらに
金属粒子を加えた後に、ジアルキルチタネート化合物及
び／又はトリアルキルチタネート化合物を添加して可
熱、架橋すると良いことが知られている。The pressure-sensitive conductive belt 44 is preferably made of a rubber material or the like which has a resistance as high as possible when no pressure is applied and has a low resistance when pressure is applied. Such a rubber material is formed, for example, by mixing conductive rubber particles with silicone rubber. Further, in order to form a pressure-sensitive conductive material having good responsiveness and little deterioration with repeated pressurization, a dialkyl titanate compound is added after adding a crosslinking agent and a crosslinking catalyst to silicone rubber and further adding metal particles. It is known that it is preferable to add a trialkyl titanate compound and / or to heat and crosslink.

【００５１】ジアルキルチタネート化合物、トリアルキ
ルチタネート化合物は全組成物の０．１〜３体積パーセ
ントが好ましい。これらのチタネート化合物は、シリコ
ーンゴムを、感圧導電性ベルト４４に添加される導電性
物質の分散に適した粘度にするとともに、導電下での変
形に対して迅速に元の形状に戻る構造に架橋すると思わ
れる。導電性金属粒子としては、従来用いられているも
のが使用できるが、銅、銀、ニッケル、ステンレス、ア
ルミニウム、チタン等及びこれらの合金が好ましい。The dialkyl titanate compound and the trialkyl titanate compound are preferably 0.1 to 3 volume percent of the total composition. These titanate compounds make the silicone rubber have a viscosity suitable for dispersion of the conductive substance added to the pressure-sensitive conductive belt 44, and have a structure that quickly returns to its original shape when deformed under conductivity. It seems to crosslink. As the conductive metal particles, those conventionally used can be used, but copper, silver, nickel, stainless steel, aluminum, titanium and the like and alloys thereof are preferable.

【００５２】導電性金属粒子の粒子径は０．１〜１５０
μｍ程度が好ましい。導電性金属粒子は、粒子径が１５
０μｍ以上になると、ゴムから離脱しやすく、０．１μ
ｍ以下であると、酸化されやすく、混合時の粘度が大き
くなってしまう。導電性金属粒子の混合量は弾性層４７
ｂに所望の導電性を付与するために８〜３５体積パーセ
ントが好ましい。シリコーンゴムには、この他に適宜顔
料、劣化防止剤、充填剤等を含有させてもよい。このよ
うにして作成した感圧導電性ベルト４４は、非加圧時に
は体積抵抗で１０6〜１０12Ωｃｍ、２ｋｇ／ｃｍ2加圧
時には１０3〜１０5Ωｃｍとなる。また、反復加圧に対
しての劣化も少なく、本転写装置に好適な材料となる。The particle size of the conductive metal particles is 0.1 to 150.
About μm is preferable. The conductive metal particles have a particle size of 15
If it is more than 0 μm, it easily separates from the rubber,
If it is m or less, it is easily oxidized and the viscosity at the time of mixing increases. The mixing amount of the conductive metal particles is the elastic layer 47.
8 to 35 volume percent is preferred to give b the desired conductivity. In addition to these, the silicone rubber may appropriately contain a pigment, a deterioration inhibitor, a filler, and the like. The pressure-sensitive conductive belt 44 thus produced has a volume resistance of 10 6 to 10 12 Ωcm when not pressed, and a pressure of 10 3 to 10 5 Ωcm when pressed at 2 kg / cm 2 . Further, it is less likely to deteriorate due to repeated pressurization, and is a material suitable for the present transfer device.

【００５３】図１３に示すように感光体４１と感圧導電
性ベルト４４とが形成するニップ幅をｔ１、感圧導電性
ベルト４４と転写部材４７とが形成するニップ幅をｔ２
とすると、ｔ１＞ｔ２であるから、感圧導電性ベルト４
４は、転写部材４７とニップを形成する幅ｔ２の部分４
４ａが転写部材４７による加圧で低抵抗となり、図１４
の実線で示すような電位分布となる。このため、感光体
４１と感圧導電性ベルト４４との間での放電が発生しに
くくなり、これによって転写チリが抑えられることを期
待できる。As shown in FIG. 13, the nip width formed by the photosensitive member 41 and the pressure-sensitive conductive belt 44 is t1, and the nip width formed by the pressure-sensitive conductive belt 44 and the transfer member 47 is t2.
Then, since t1> t2, the pressure-sensitive conductive belt 4
4 is a portion 4 having a width t2 that forms a nip with the transfer member 47.
4a has a low resistance due to the pressure applied by the transfer member 47.
The potential distribution is as shown by the solid line. For this reason, discharge is less likely to occur between the photoconductor 41 and the pressure-sensitive conductive belt 44, which can be expected to suppress transfer dust.

【００５４】なお、図１４の破線は転写搬送ベルト４４
として感圧導電性ではない中抵抗ベルトを用いた場合の
転写搬送ベルト４４の転写部材４７とのニップ部近傍の
電位分布である。ただし、転写バイアスは感圧導電性ベ
ルトの場合と中抵抗ベルトの場合とでピーク値が同じに
なるように調整してある。また、図１４においてＸは転
写搬送ベルト４４の記録紙搬送方向位置を示し、Ｖは転
写搬送ベルト４４の電位を示す。The broken line in FIG. 14 indicates the transfer / transport belt 44.
Is a potential distribution in the vicinity of a nip portion between the transfer / transport belt 44 and the transfer member 47 when a medium resistance belt that is not pressure-sensitive conductive is used. However, the transfer bias is adjusted so that the peak values are the same for the pressure sensitive conductive belt and the medium resistance belt. Further, in FIG. 14, X indicates the position of the transfer / transport belt 44 in the recording paper transport direction, and V indicates the potential of the transfer / transport belt 44.

【００５５】中抵抗ベルトの場合は、転写部材４７との
ニップ部の入口及び出口で感光体４１との間に大きな電
位差が生ずるので、放電によるチリが発生する恐れがあ
る。また、感圧導電性ベルトの場合も、仮にｔ１＜ｔ２
とすれば、中抵抗ベルトの場合と同様に図１４の破線の
ような電位分布になることが予想され、この場合にも放
電が発生する恐れがある。In the case of the medium resistance belt, a large potential difference is generated between the transfer member 47 and the photosensitive member 41 at the entrance and the exit of the nip portion, so that dust may be generated due to discharge. In the case of a pressure-sensitive conductive belt, t1 <t2
If so, it is expected that the potential distribution will be as shown by the broken line in FIG. 14 as in the case of the medium resistance belt, and in this case as well, discharge may occur.

【００５６】このように、第５実施形態例は、請求項７
記載の発明の実施形態例であって、静電像担持体として
の感光体４１に対して均一な初期帯電を行った後に部分
的に初期帯電を消去して静電荷のパターンを形成し、該
静電荷のパターンをトナーにより現像して記録紙４３に
転写する画像形成装置の転写装置において、記録紙４３
を搬送する感圧導電性ベルト４４と、この感圧導電性ベ
ルト４４の裏側を転写位置付近で押圧しバイアスが印加
されて転写電界を形成させることにより静電像担持体４
１上のトナーを記録紙４３に転写せしめる転写部材４７
とを備え、この転写部材４７を弾性層４７ｂを含むロー
ラ構造としたので、感圧導電性ベルト４４と転写部材４
７との間の摩耗を少なくできて感圧導電性ベルト４４や
転写部材４７の摩耗を抑えることができ、装置の高寿命
化を実現することができる。また、弾性層４７ｂにより
感圧導電性ベルト４４と転写部材４７との密着性を向上
させて転写部材４７から感圧導電性ベルト４４へ効率良
く圧力を加えることができ、記録紙４３が感圧導電性ベ
ルト４４と転写部材４７とのニップ部から排出されたと
きの静電像担持体４１への衝撃を少なくして静電像担持
体４１の劣化を防ぐことができる。As described above, the fifth embodiment is characterized by claim 7.
In the embodiment of the invention described, the photosensitive body 41 as an electrostatic image bearing member is subjected to uniform initial charging, and then the initial charging is partially erased to form an electrostatic charge pattern. In a transfer device of an image forming apparatus that develops an electrostatic charge pattern with toner and transfers it to the recording paper 43,
The pressure-sensitive conductive belt 44 that conveys the electrostatic image bearing member 4 and the back side of the pressure-sensitive conductive belt 44 are pressed near the transfer position and a bias is applied to form a transfer electric field.
A transfer member 47 for transferring the toner on the recording paper 43 onto the recording paper 43.
Since the transfer member 47 has a roller structure including the elastic layer 47b, the pressure-sensitive conductive belt 44 and the transfer member 4 are provided.
The wear between the pressure sensitive conductive belt 44 and the transfer member 47 can be suppressed, and the life of the apparatus can be extended. Further, the elastic layer 47b improves the adhesion between the pressure-sensitive conductive belt 44 and the transfer member 47 so that pressure can be efficiently applied from the transfer member 47 to the pressure-sensitive conductive belt 44. It is possible to prevent the electrostatic image carrier 41 from deteriorating by reducing the impact on the electrostatic image carrier 41 when discharged from the nip portion between the conductive belt 44 and the transfer member 47.

【００５７】また、第５実施形態例は、請求項８記載の
発明の実施形態例であって、静電像担持体としての感光
体４１に対して均一な初期帯電を行った後に部分的に初
期帯電を消去して静電荷のパターンを形成し、該静電荷
のパターンをトナーにより現像して記録紙４３に転写す
る画像形成装置の転写装置において、記録紙４３を搬送
する感圧導電性ベルト４４と、この感圧導電性ベルト４
４の裏側を転写位置付近で押圧しバイアスが印加されて
転写電界を形成させることにより静電像担持体４１上の
トナーを記録紙４３に転写せしめる転写部材４７とを備
え、静電像担持体４１と感圧導電性ベルト４４が形成す
るニップ幅をｔ１、感圧導電性ベルト４４と転写部材４
７が形成するニップ幅をｔ２としたとき、ｔ１＞ｔ２と
したので、静電像担持体４１と感圧導電性ベルト４４と
の間の不要な放電を防止して転写チリを抑制することが
でき、高画質化を図ることができる。Further, the fifth embodiment is an embodiment of the invention described in claim 8 and is partially conducted after uniform initial charging is performed on the photosensitive member 41 as an electrostatic image bearing member. In a transfer device of an image forming apparatus that erases initial charge to form an electrostatic charge pattern, develops the electrostatic charge pattern with toner, and transfers the electrostatic charge pattern onto the recording paper 43, a pressure-sensitive conductive belt that conveys the recording paper 43. 44 and this pressure-sensitive conductive belt 4
And a transfer member 47 for transferring the toner on the electrostatic image bearing member 41 to the recording paper 43 by pressing the back side of the No. 4 near the transfer position and applying a bias to form a transfer electric field. 41, the nip width formed by the pressure-sensitive conductive belt 44 and the pressure-sensitive conductive belt 44 is t1.
When the nip width formed by 7 is t2, t1> t2. Therefore, unnecessary discharge between the electrostatic image carrier 41 and the pressure-sensitive conductive belt 44 can be prevented and transfer dust can be suppressed. Therefore, high image quality can be achieved.

【００５８】次に、請求項７、８記載の発明の第１実施
例について説明する。この第１実施例では、上記第５実
施形態例において、シリコーンゴム７９ｖｏｌ％、ジア
ルキルチタネート化合物１ｖｏｌ％、金属粒子２０ｖｏ
ｌ％、の組成で厚さ５００μｍのベルトを作成し、その
表面（表、裏の両面）にナイロンに水溶性エポキシ樹脂
を添加した溶液を１０μｍ厚に塗布し、１５０℃で１５
分間加熱、架橋し、感圧導電性ベルト４４を作成した。Next, a first embodiment of the invention described in claims 7 and 8 will be described. In the first embodiment, in the fifth embodiment, 79 vol% of silicone rubber, 1 vol% of dialkyl titanate compound, and 20 vo of metal particles are used.
A belt having a composition of 1% and a thickness of 500 μm is prepared, and a solution of water-soluble epoxy resin added to nylon is applied on the surface (both front and back) to a thickness of 10 μm, and the belt is applied at 150 ° C. for 15 minutes.
The pressure-sensitive conductive belt 44 was prepared by heating and crosslinking for minutes.

【００５９】この感圧導電性ベルト４４は、２つのロー
ラ１２、１３間に張られ、有機感光体ドラムからなる静
電像担持体４１に密着される。転写部材４７は、半径６
ｍｍのローラが用いられて約１ｋｇ重のバネによる圧力
で感圧導電性ベルト４４の裏面に押し当てられる。この
ローラ４７は、１０7Ωｃｍのエピクロルヒドリンゴム
で形成されており、硬度がＪＩＳ−Ａで３５度であり、
表面には表面抵抗１０8Ω／□のナイロンからなる保護
層が設けられている。The pressure-sensitive conductive belt 44 is stretched between the two rollers 12 and 13 and is brought into close contact with the electrostatic image carrier 41 composed of an organic photosensitive drum. The transfer member 47 has a radius of 6
mm roller is used and pressed against the back surface of the pressure-sensitive conductive belt 44 by the pressure of a spring having a weight of about 1 kg. The roller 47 is made of epichlorohydrin rubber of 10 7 Ωcm and has a hardness of 35 degrees according to JIS-A.
A protective layer made of nylon having a surface resistance of 10 8 Ω / □ is provided on the surface.

【００６０】感光体４１上に上述のようにトナー像を形
成し、このトナー像を記録紙４３上に転写してトナーの
転写率、電源４８から供給される電流値を測定した。図
１５は本実施例における電源４８から転写部材４７に印
加する転写バイアス電圧と、トナーの転写率、電源４８
から転写部材４７への電流値を測定した結果を示す。ま
た、本実施例において、体積抵抗１０8Ωｃｍのクロロ
ブレンゴムにウレタンをコートしたベルトを転写搬送ベ
ルト４４として用いるようにした比較例１について、同
様にトナーの転写率、電源４８から供給される電流値を
測定した。また、本実施例において、表面層のない感圧
導電性ゴムを転写搬送ベルト４４として用いるようにし
た比較例２について、同様にトナーの転写率、電源４８
から供給される電流値を測定した。A toner image was formed on the photoconductor 41 as described above, this toner image was transferred onto the recording paper 43, and the toner transfer rate and the current value supplied from the power source 48 were measured. FIG. 15 shows the transfer bias voltage applied from the power source 48 to the transfer member 47, the toner transfer rate, and the power source 48 in this embodiment.
The result of measuring the current value from the to the transfer member 47 is shown. Further, in Comparative Example 1 in which a belt formed by coating urethane on chlorobrene rubber having a volume resistance of 10 8 Ωcm is used as the transfer / conveying belt 44 in this embodiment, the toner transfer rate is similarly supplied from the power source 48. The current value was measured. Further, in Comparative Example 2 in which the pressure-sensitive conductive rubber having no surface layer is used as the transfer / conveying belt 44 in this embodiment, the toner transfer rate and the power source 48 are similarly set.
The electric current value supplied from was measured.

【００６１】クロロブレンゴムにウレタンをコートした
ベルトを転写搬送ベルト４４として用いるようにした比
較例１では、転写搬送ベルトの厚さ方向の抵抗が感圧導
電性ベルトの厚さ方向の抵抗に比べて大きいので、十分
な転写電界を確保するためには、電源４８から高電圧を
転写部材４７に印加する必要があった。また、表面層の
ない感圧導電性ゴムを転写搬送ベルト４４として用いる
ようにした比較例２では、電源４８から転写部材４７に
印加する電圧が低電圧であっても十分な転写電界が形成
されるが、感圧導電性ゴムの周方向に電流が流れてしま
い、電源４８から転写部材４７への電流値が大きくなっ
てしまうという結果が得られた。表面に保護層を有する
感圧導電性ゴムからなるベルトを転写搬送ベルト４４と
して用いるようにした本実施例では、転写バイアスが少
なくても９０％以上の転写率を確保でき、電源４８から
転写部材４７への電流値が少なくて済んで省電力化を図
ることができることが分かった。In Comparative Example 1 in which a belt formed by coating chlorobrene rubber with urethane was used as the transfer / transport belt 44, the resistance in the thickness direction of the transfer / transport belt was compared with the resistance in the thickness direction of the pressure-sensitive conductive belt. Therefore, in order to secure a sufficient transfer electric field, it is necessary to apply a high voltage from the power source 48 to the transfer member 47. Further, in Comparative Example 2 in which the pressure-sensitive conductive rubber having no surface layer is used as the transfer / transport belt 44, a sufficient transfer electric field is formed even if the voltage applied from the power source 48 to the transfer member 47 is low. However, the result is that a current flows in the circumferential direction of the pressure-sensitive conductive rubber and the current value from the power source 48 to the transfer member 47 increases. In the present embodiment in which a belt made of pressure-sensitive conductive rubber having a protective layer on its surface is used as the transfer / conveying belt 44, a transfer rate of 90% or more can be secured even with a small transfer bias, and the transfer member from the power supply 48 can be secured. It was found that the current value to 47 was small and power saving could be achieved.

【００６２】次に、請求項７、８記載の発明の第２実施
例について説明する。この第２実施例では、上記第１実
施例において、感光体４１、感圧導電性ベルト４４、転
写部材４７の配置を変えるようにした。この第２実施例
では感光体４１、感圧導電性ベルト４４、転写部材４７
の配置を変えることでｔ１、ｔ２を変えて転写の様子を
確認したところ、図１６に示すような結果が得られた。
ここに、電源４８から転写部材４７に印加する転写バイ
アス電圧は＋８００Ｖとした。この結果から、ｔ１＞ｔ
２としたことにより、静電像担持体４１と感圧導電性ベ
ルト４４との間の不要な放電を防止して転写チリを抑制
することができ、高画質化を計ることができることが分
かる。Next, a second embodiment of the invention described in claims 7 and 8 will be described. In the second embodiment, the arrangement of the photoconductor 41, the pressure-sensitive conductive belt 44, and the transfer member 47 in the first embodiment is changed. In the second embodiment, the photoconductor 41, the pressure-sensitive conductive belt 44, the transfer member 47.
When the transfer state was confirmed by changing the arrangement of and changing t1 and t2, the results shown in FIG. 16 were obtained.
Here, the transfer bias voltage applied from the power source 48 to the transfer member 47 was set to + 800V. From this result, t1> t
By setting the value to 2, it is understood that unnecessary discharge between the electrostatic image carrier 41 and the pressure-sensitive conductive belt 44 can be prevented, transfer dust can be suppressed, and high image quality can be achieved.

【００６３】[0063]

【発明の効果】以上のように請求項１記載の発明によれ
ば、静電像担持体に対して均一な初期帯電を行った後に
部分的に初期帯電を消去して静電荷のパターンを形成
し、該静電荷のパターンをトナーにより現像して記録紙
あるいは中間転写体に転写する画像形成装置の転写装置
において、前記静電像担持体に押し付けられて前記トナ
ーの帯電極性とは逆の極性の電圧が印加され、前記静電
像担持体との間に介在する前記記録紙あるいは前記中間
転写体に前記静電像担持体からトナーを転写させる加圧
導電性部材を備えたので、転写電界を転写ニップ部に集
中して発生させることができて転写ニップ部においての
み転写を行うことができ、高画質を図ることができる。
また、転写ニップ部においては抵抗が小さくなり、転写
電界を作り出すための印加電圧を小さくすることができ
る。As described above, according to the first aspect of the invention, after the uniform initial charging is performed on the electrostatic image bearing member, the initial charging is partially erased to form an electrostatic charge pattern. Then, in a transfer device of an image forming apparatus that develops the electrostatic charge pattern with toner and transfers the electrostatic charge pattern onto recording paper or an intermediate transfer member, the polarity is opposite to the charging polarity of the toner when pressed against the electrostatic image carrier. Is provided with a pressure conductive member for transferring toner from the electrostatic image carrier to the recording paper or the intermediate transfer medium that is interposed between the electrostatic image carrier and the electrostatic image carrier. Can be generated in a concentrated manner at the transfer nip portion, transfer can be performed only at the transfer nip portion, and high image quality can be achieved.
Further, the resistance is reduced in the transfer nip portion, and the applied voltage for creating the transfer electric field can be reduced.

【００６４】請求項２記載の発明によれば、請求項１記
載の転写装置において、前記加圧導電性部材は金属ロー
ラの表面に設けてローラ形状としたので、構成が簡易
で、静電像担持体への負荷が大きくならない。According to the second aspect of the invention, in the transfer device according to the first aspect, the pressure conductive member is provided on the surface of the metal roller and has a roller shape, so that the structure is simple and the electrostatic image is formed. The load on the carrier does not increase.

【００６５】請求項３記載の発明によれば、静電像担持
体に対して均一な初期帯電を行った後に部分的に初期帯
電を消去して静電荷のパターンを形成し、該静電荷のパ
ターンをトナーにより現像して記録紙に転写する画像形
成装置の転写装置において、前記記録紙を搬送する転写
搬送ベルトと、この転写搬送ベルトの裏側に前記記録紙
が前記静電像担持体と接触する位置付近で接触し前記ト
ナーの帯電極性とは逆の極性の電圧が印加されて前記静
電像担持体から前記記録紙へトナーを転写させる加圧導
電性部材を備えたので、記録紙の搬送が安定化し、記録
紙の高速搬送が可能となる。また、転写が静電像担持体
と記録紙とのニップ部でのみ行われ、画質劣化がない。According to the third aspect of the present invention, the initial charge is uniformly applied to the electrostatic image bearing member, and then the initial charge is partially erased to form an electrostatic charge pattern. In a transfer device of an image forming apparatus that develops a pattern with toner and transfers it to recording paper, a transfer conveyance belt that conveys the recording paper, and the recording paper contacts the electrostatic image carrier on the back side of the transfer conveyance belt. Since a pressure conductive member for contacting near the position where the electrostatic charge of the toner is applied to transfer the toner from the electrostatic image carrier to the recording paper is provided, Conveyance is stabilized, and recording paper can be conveyed at high speed. Further, the transfer is performed only at the nip portion between the electrostatic image carrier and the recording paper, and the image quality is not deteriorated.

【００６６】請求項４記載の発明によれば、静電像担持
体に対して均一な初期帯電を行った後に部分的に初期帯
電を消去して静電荷のパターンを形成し、該静電荷のパ
ターンをトナーにより現像して記録紙に転写する画像形
成装置の転写装置において、加圧導電性部材で構成され
前記記録紙を搬送する転写搬送ベルトと、この転写搬送
ベルトの裏側に前記記録紙が前記静電像担持体と接触す
る位置付近で接触し前記トナーの帯電極性とは逆の極性
の電圧が印加されて前記静電像担持体から前記記録紙へ
トナーを転写させる加圧部材とを備えたので、より低い
電圧で転写を行うことができる。According to the fourth aspect of the present invention, the uniform electrostatic charge is applied to the electrostatic image carrier, and then the electrostatic charge is partially erased to form an electrostatic charge pattern. In a transfer device of an image forming apparatus that develops a pattern with toner and transfers it to recording paper, a transfer conveyor belt configured by a pressure conductive member for conveying the recording paper, and the recording paper on the back side of the transfer conveyor belt. A pressing member that contacts the electrostatic image bearing member in the vicinity thereof and is applied with a voltage having a polarity opposite to the charging polarity of the toner to transfer the toner from the electrostatic image bearing member to the recording sheet. Since it is provided, the transfer can be performed at a lower voltage.

【００６７】請求項５記載の発明によれば、請求項１、
３または４記載の転写装置において、前記画像形成装置
の非画像形成時に当該転写装置を前記静電像担持体に対
して非接触状態とする手段を備えたので、加圧導電性部
材の材料が溶着することがなくなり、耐久性が向上す
る。According to the invention of claim 5, claim 1,
In the transfer device according to 3 or 4, since a means for bringing the transfer device into a non-contact state with the electrostatic image carrier when the image forming device is not forming an image is provided, the material of the pressure conductive member is No welding occurs and durability is improved.

【００６８】請求項６記載の発明によれば、請求項１、
３または４記載の転写装置において、当該転写装置の前
記静電像担持体との接触面側に高抵抗層を設けたので、
静電像担持体にピンホールがある場合にも、過大電流が
流れてシステムがダウンしたりや転写不良が生じたりす
ることがなくなる。According to the invention of claim 6, claim 1,
In the transfer device according to 3 or 4, since the high resistance layer is provided on the contact surface side of the transfer device with the electrostatic image carrier,
Even if there is a pinhole on the electrostatic image carrier, an excessive current will not flow and the system will not go down or a transfer failure will not occur.

【００６９】請求項７記載の発明によれば、静電像担持
体に対して均一な初期帯電を行った後に部分的に初期帯
電を消去して静電荷のパターンを形成し、該静電荷のパ
ターンをトナーにより現像して記録紙に転写する画像形
成装置の転写装置において、前記記録紙を搬送する感圧
導電性ベルトと、この感圧導電性ベルトの裏側を転写位
置付近で押圧しバイアスが印加されて転写電界を形成さ
せることにより前記静電像担持体上のトナーを前記記録
紙に転写せしめる転写部材とを備え、この転写部材を弾
性層を含むローラ構造としたので、感圧導電性ベルトと
転写部材との間の摩耗を少なくできて感圧導電性ベルト
や転写部材の摩耗を抑えることができ、装置の高寿命化
を実現することができる。また、転写部材の弾性層によ
り感圧導電性ベルトと転写部材との密着性を向上させて
転写部材から感圧導電性ベルトへ効率良く圧力を加える
ことができ、記録紙が感圧導電性ベルトと転写部材との
ニップ部から排出されたときの静電像担持体への衝撃を
少なくして静電像担持体の劣化を防ぐことができる。According to the invention described in claim 7, after the initial charging is uniformly performed on the electrostatic image bearing member, the initial charging is partially erased to form an electrostatic charge pattern. In a transfer device of an image forming apparatus that develops a pattern with toner and transfers it to recording paper, a pressure-sensitive conductive belt that conveys the recording paper and the back side of the pressure-sensitive conductive belt are pressed near a transfer position to apply a bias. A transfer member for transferring the toner on the electrostatic image bearing member to the recording paper by applying a transfer electric field is formed. The transfer member has a roller structure including an elastic layer. The wear between the belt and the transfer member can be reduced, the wear of the pressure-sensitive conductive belt and the transfer member can be suppressed, and the life of the apparatus can be extended. In addition, the elastic layer of the transfer member improves the adhesion between the pressure-sensitive conductive belt and the transfer member, so that pressure can be efficiently applied from the transfer member to the pressure-sensitive conductive belt. It is possible to prevent the electrostatic image bearing member from deteriorating by reducing the impact on the electrostatic image bearing member when discharged from the nip portion between the transfer member and the transfer member.

【００７０】請求項８記載の発明によれば、静電像担持
体に対して均一な初期帯電を行った後に部分的に初期帯
電を消去して静電荷のパターンを形成し、該静電荷のパ
ターンをトナーにより現像して記録紙に転写する画像形
成装置の転写装置において、前記記録紙を搬送する感圧
導電性ベルトと、この感圧導電性ベルトの裏側を転写位
置付近で押圧しバイアスが印加されて転写電界を形成さ
せることにより前記静電像担持体上のトナーを前記記録
紙に転写せしめる転写部材とを備え、前記静電像担持体
と前記感圧導電性ベルトが形成するニップ幅をｔ１、前
記感圧導電性ベルトと前記転写部材が形成するニップ幅
をｔ２としたとき、ｔ１＞ｔ２としたので、静電像担持
体と感圧導電性ベルトとの間の不要な放電を防止して転
写チリを抑制することができ、高画質化を計ることがで
きる。According to the eighth aspect of the present invention, after the uniform initial charging is performed on the electrostatic image bearing member, the initial charging is partially erased to form an electrostatic charge pattern. In a transfer device of an image forming apparatus that develops a pattern with toner and transfers it to recording paper, a pressure-sensitive conductive belt that conveys the recording paper and the back side of the pressure-sensitive conductive belt are pressed near a transfer position to apply a bias. A transfer member for transferring the toner on the electrostatic image carrier to the recording paper by forming a transfer electric field when applied, and a nip width formed by the electrostatic image carrier and the pressure-sensitive conductive belt. Where t1 and t2 are the nip widths formed by the pressure-sensitive conductive belt and the transfer member, t1> t2. Therefore, unnecessary discharge between the electrostatic image carrier and the pressure-sensitive conductive belt occurs. Prevent and suppress transfer dust Door can be, it is possible to measure the image quality.

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

【図１】本発明の第１実施形態例乃至第４実施形態例の
基本構成を示す概略図である。FIG. 1 is a schematic diagram showing a basic configuration of first to fourth exemplary embodiments of the present invention.

【図２】同実施形態例における感光体と加圧導電性部材
とにより形成される転写ニップ部を拡大して示す正面図
である。FIG. 2 is an enlarged front view showing a transfer nip portion formed by a photosensitive member and a pressure conductive member in the embodiment.

【図３】同実施形態例の転写ニップ部における感光体と
加圧導電性部材との間の圧力の分布を示す図である。FIG. 3 is a diagram showing a pressure distribution between a photoconductor and a pressure conductive member in a transfer nip portion of the embodiment.

【図４】同実施形態例における加圧導電性部材の抵抗分
布を示す図である。FIG. 4 is a diagram showing a resistance distribution of the pressure conductive member according to the embodiment.

【図５】本発明の第１実施形態例を示す概略図である。FIG. 5 is a schematic view showing a first embodiment example of the present invention.

【図６】本発明の第２実施形態例を示す概略図である。FIG. 6 is a schematic view showing a second embodiment example of the present invention.

【図７】本発明の他の実施形態例を示す概略図である。FIG. 7 is a schematic view showing another embodiment example of the present invention.

【図８】本発明の第４実施形態例を示す概略図である。FIG. 8 is a schematic diagram showing a fourth exemplary embodiment of the present invention.

【図９】従来の転写ローラを用いた転写装置の一例を示
す概略図である。FIG. 9 is a schematic view showing an example of a transfer device using a conventional transfer roller.

【図１０】同転写装置の一部を示す正面図である。FIG. 10 is a front view showing a part of the transfer device.

【図１１】従来のベルトを用いた転写装置の１例を示す
概略図である。FIG. 11 is a schematic view showing an example of a transfer device using a conventional belt.

【図１２】本発明の第５実施形態例を示す概略図であ
る。FIG. 12 is a schematic view showing a fifth exemplary embodiment of the present invention.

【図１３】同第５実施形態例の一部を拡大して示す正面
図である。FIG. 13 is an enlarged front view showing a part of the fifth embodiment.

【図１４】同第５実施形態例の感圧導電性ベルトと比較
例の中抵抗ベルトの電位分布を示す図である。FIG. 14 is a diagram showing potential distributions of the pressure-sensitive conductive belt of the fifth embodiment and the medium resistance belt of the comparative example.

【図１５】本発明の第１実施例の実験結果を示す図であ
る。FIG. 15 is a diagram showing experimental results of the first example of the present invention.

【図１６】本発明の第２実施例の実験結果を示す図であ
る。FIG. 16 is a diagram showing experimental results of the second example of the present invention.

【符号の説明】[Explanation of symbols]

２１、４１ 感光体 ２２、４２ 転写装置 ２３、４３ 記録紙 ２５ 加圧導電性部材 ２６ 加圧部材 ２７、４８ 電源 ２８ 転写ローラ ３０、３４、４４ 転写搬送ベルト ３５ 加圧ローラ ４７ 転写部材 ４７ｂ 弾性層 21, 41 Photoreceptor 22, 42 Transfer Device 23, 43 Recording Paper 25 Pressure Conductive Member 26 Pressure Member 27, 48 Power Supply 28 Transfer Roller 30, 34, 44 Transfer Conveyor Belt 35 Pressure Roller 47 Transfer Member 47b Elastic Layer

Claims (8)

【特許請求の範囲】[Claims] 【請求項１】静電像担持体に対して均一な初期帯電を行
った後に部分的に初期帯電を消去して静電荷のパターン
を形成し、該静電荷のパターンをトナーにより現像して
記録紙あるいは中間転写体に転写する画像形成装置の転
写装置において、前記静電像担持体に押し付けられて前
記トナーの帯電極性とは逆の極性の電圧が印加され、前
記静電像担持体との間に介在する前記記録紙あるいは前
記中間転写体に前記静電像担持体からトナーを転写させ
る加圧導電性部材を備えたことを特徴とする転写装置。1. A uniform initial charge is applied to an electrostatic image bearing member, and then the initial charge is partially erased to form an electrostatic charge pattern, and the electrostatic charge pattern is developed with a toner for recording. In a transfer device of an image forming apparatus that transfers to paper or an intermediate transfer member, a voltage having a polarity opposite to the charging polarity of the toner is applied by being pressed against the electrostatic image carrier, A transfer device comprising a pressure conductive member for transferring toner from the electrostatic image carrier to the recording paper or the intermediate transfer body interposed therebetween. 【請求項２】請求項１記載の転写装置において、前記加
圧導電性部材は金属ローラの表面に設けてローラ形状と
したことを特徴とする転写装置。2. The transfer device according to claim 1, wherein the pressure conductive member is provided on the surface of a metal roller and has a roller shape. 【請求項３】静電像担持体に対して均一な初期帯電を行
った後に部分的に初期帯電を消去して静電荷のパターン
を形成し、該静電荷のパターンをトナーにより現像して
記録紙に転写する画像形成装置の転写装置において、前
記記録紙を搬送する転写搬送ベルトと、この転写搬送ベ
ルトの裏側に前記記録紙が前記静電像担持体と接触する
位置付近で接触し前記トナーの帯電極性とは逆の極性の
電圧が印加されて前記静電像担持体から前記記録紙へト
ナーを転写させる加圧導電性部材を備えたことを特徴と
する転写装置。3. An electrostatic image carrier is uniformly pre-charged, and then the initial charge is partially erased to form an electrostatic charge pattern, and the electrostatic charge pattern is developed with a toner for recording. In a transfer device of an image forming apparatus that transfers to a paper, a transfer conveyor belt that conveys the recording paper and the toner that contacts the back side of the transfer conveyor belt near the position where the recording paper contacts the electrostatic image carrier. 2. A transfer device comprising a pressure conductive member for applying a voltage having a polarity opposite to the charging polarity of No. 1 to transfer toner from the electrostatic image carrier to the recording paper. 【請求項４】静電像担持体に対して均一な初期帯電を行
った後に部分的に初期帯電を消去して静電荷のパターン
を形成し、該静電荷のパターンをトナーにより現像して
記録紙に転写する画像形成装置の転写装置において、加
圧導電性部材で構成され前記記録紙を搬送する転写搬送
ベルトと、この転写搬送ベルトの裏側に前記記録紙が前
記静電像担持体と接触する位置付近で接触し前記トナー
の帯電極性とは逆の極性の電圧が印加されて前記静電像
担持体から前記記録紙へトナーを転写させる加圧部材と
を備えたことを特徴とする転写装置。4. A uniform initial charge is applied to an electrostatic image bearing member, and then the initial charge is partially erased to form an electrostatic charge pattern, and the electrostatic charge pattern is developed with toner and recorded. In a transfer device of an image forming apparatus for transferring onto paper, a transfer / transport belt composed of a pressure conductive member for transporting the recording paper, and the recording paper contacting the electrostatic image carrier on the back side of the transfer / transport belt. And a pressurizing member that is contacted near the position to apply a voltage having a polarity opposite to the charging polarity of the toner to transfer the toner from the electrostatic image carrier to the recording sheet. apparatus. 【請求項５】請求項１、３または４記載の転写装置にお
いて、前記画像形成装置の非画像形成時に当該転写装置
を前記静電像担持体に対して非接触状態とする手段を備
えたことを特徴とする転写装置。5. The transfer device according to claim 1, 3 or 4, further comprising means for bringing the transfer device into a non-contact state with the electrostatic image carrier when the image forming device is not forming an image. Transfer device characterized by. 【請求項６】請求項１、３または４記載の転写装置にお
いて、当該転写装置の前記静電像担持体との接触面側に
高抵抗層を設けたことを特徴とする転写装置。6. The transfer device according to claim 1, 3 or 4, wherein a high resistance layer is provided on a contact surface side of the transfer device with the electrostatic image carrier. 【請求項７】静電像担持体に対して均一な初期帯電を行
った後に部分的に初期帯電を消去して静電荷のパターン
を形成し、該静電荷のパターンをトナーにより現像して
記録紙に転写する画像形成装置の転写装置において、前
記記録紙を搬送する感圧導電性ベルトと、この感圧導電
性ベルトの裏側を転写位置付近で押圧しバイアスが印加
されて転写電界を形成させることにより前記静電像担持
体上のトナーを前記記録紙に転写せしめる転写部材とを
備え、この転写部材を弾性層を含むローラ構造としたこ
とを特徴とする転写装置。7. A uniform initial charge is applied to an electrostatic image bearing member, and then the initial charge is partially erased to form an electrostatic charge pattern, and the electrostatic charge pattern is developed with a toner for recording. In a transfer device of an image forming apparatus for transferring to a paper, a pressure-sensitive conductive belt that conveys the recording paper and a back side of the pressure-sensitive conductive belt are pressed near a transfer position to apply a bias to form a transfer electric field. And a transfer member configured to transfer the toner on the electrostatic image carrier onto the recording paper, and the transfer member has a roller structure including an elastic layer. 【請求項８】静電像担持体に対して均一な初期帯電を行
った後に部分的に初期帯電を消去して静電荷のパターン
を形成し、該静電荷のパターンをトナーにより現像して
記録紙に転写する画像形成装置の転写装置において、前
記記録紙を搬送する感圧導電性ベルトと、この感圧導電
性ベルトの裏側を転写位置付近で押圧しバイアスが印加
されて転写電界を形成させることにより前記静電像担持
体上のトナーを前記記録紙に転写せしめる転写部材とを
備え、前記静電像担持体と前記感圧導電性ベルトが形成
するニップ幅をｔ１、前記感圧導電性ベルトと前記転写
部材が形成するニップ幅をｔ２としたとき、ｔ１＞ｔ２
としたことを特徴とする転写装置。8. A uniform initial charge is applied to an electrostatic image bearing member, and then the initial charge is partially erased to form an electrostatic charge pattern, and the electrostatic charge pattern is developed with a toner and recorded. In a transfer device of an image forming apparatus for transferring to a paper, a pressure-sensitive conductive belt that conveys the recording paper and a back side of the pressure-sensitive conductive belt are pressed near a transfer position to apply a bias to form a transfer electric field. A transfer member for transferring the toner on the electrostatic image bearing member to the recording paper, and the nip width formed by the electrostatic image bearing member and the pressure sensitive conductive belt is t1, and the pressure sensitive conductivity is When the nip width formed by the belt and the transfer member is t2, t1> t2
The transfer device characterized in that
JP21728195A 1995-08-25 1995-08-25 Transfer device Pending JPH0962114A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP21728195A JPH0962114A (en) 1995-08-25 1995-08-25 Transfer device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP21728195A JPH0962114A (en) 1995-08-25 1995-08-25 Transfer device

Publications (1)

Publication Number Publication Date
JPH0962114A true JPH0962114A (en) 1997-03-07

Family

ID=16701686

Family Applications (1)

Application Number Title Priority Date Filing Date
JP21728195A Pending JPH0962114A (en) 1995-08-25 1995-08-25 Transfer device

Country Status (1)

Country Link
JP (1) JPH0962114A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006106255A (en) * 2004-10-04 2006-04-20 Sumitomo Rubber Ind Ltd Intermediate transfer member
JP2006189614A (en) * 2005-01-06 2006-07-20 Fuji Xerox Co Ltd Image forming apparatus
JP2011070040A (en) * 2009-09-26 2011-04-07 Konica Minolta Business Technologies Inc Transfer pad, transfer belt unit, and image forming apparatus

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006106255A (en) * 2004-10-04 2006-04-20 Sumitomo Rubber Ind Ltd Intermediate transfer member
JP4536475B2 (en) * 2004-10-04 2010-09-01 住友ゴム工業株式会社 Intermediate transfer member
JP2006189614A (en) * 2005-01-06 2006-07-20 Fuji Xerox Co Ltd Image forming apparatus
JP4649991B2 (en) * 2005-01-06 2011-03-16 富士ゼロックス株式会社 Image forming apparatus
JP2011070040A (en) * 2009-09-26 2011-04-07 Konica Minolta Business Technologies Inc Transfer pad, transfer belt unit, and image forming apparatus

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