JPH1124452A - Image forming device - Google Patents

Image forming device

Info

Publication number
JPH1124452A
JPH1124452A JP9189257A JP18925797A JPH1124452A JP H1124452 A JPH1124452 A JP H1124452A JP 9189257 A JP9189257 A JP 9189257A JP 18925797 A JP18925797 A JP 18925797A JP H1124452 A JPH1124452 A JP H1124452A
Authority
JP
Japan
Prior art keywords
image carrier
transfer
image
cam
rotation
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
JP9189257A
Other languages
Japanese (ja)
Inventor
Takeo Suda
武男 須田
Hiroshi Yoshinaga
洋 吉永
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 JP9189257A priority Critical patent/JPH1124452A/en
Publication of JPH1124452A publication Critical patent/JPH1124452A/en
Pending legal-status Critical Current

Links

Landscapes

  • Cleaning In Electrography (AREA)
  • Electrophotography Configuration And Component (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)

Abstract

PROBLEM TO BE SOLVED: To enable the contact/uncontact of transfer member with the surface of an image carrier, without using an exclusive motor by separating the transfer member from the surface of the image carrier with its rotation, at the time of rotating the image carrier in a second direction. SOLUTION: A transfer roller 11 is supported to enable the contact/uncontact with the surface of a photoreceptor 5 and when it is rotated in the second direction, the transfer roller 11 is separated from the photoreceptor 5 by using this rotation as a drive source. In other words, a cam 38 is attached to the roller shaft 28 of the roller 11 and a one-way clutch 39 is interposed between the cam 38 and the roller shaft 28. When the photoreceptor 5 is rotated in the second direction, after an image forming operation is completed, the rotation of the roller shaft 28 of the roller 11 rotated in the second direction is transmitted to the cam 38 and when this can 38 is turned, it is engaged with an end member 22 on the side of the photoreceptor 5, so that the transfer roller 11 is separated from the surface of the photoreceptor 5, against the workings of springs 33 and 34.

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、第１の方向に回転
駆動されつつ表面にトナー像を形成される像担持体と、
転写材を介して像担持体表面に当接しながら像担持体表
面に形成されたトナー像を転写材に転写するための転写
部材と、トナー像転写後の像担持体表面に付着する転写
残トナーを像担持体表面から除去して当該像担持体表面
を清掃するクリーニング部材とを具備し、前記像担持体
は、前記第１の方向とは逆の第２の方向にも回転可能で
ある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 carrier having a surface on which a toner image is formed while being driven to rotate in a first direction;
A transfer member for transferring the toner image formed on the surface of the image carrier to the transfer material while contacting the surface of the image carrier via the transfer material; and a transfer residual toner adhered to the surface of the image carrier after the transfer of the toner image And a cleaning member for cleaning the surface of the image carrier by removing the image carrier from the surface of the image carrier, wherein the image carrier is rotatable also in a second direction opposite to the first direction. The present invention relates to a forming apparatus.

【０００２】[0002]

【従来の技術】複写機、プリンタ、ファクシミリ、或い
はこれらの少なくとも２つの機能を備えた複合機などと
して構成される画像形成装置においては、像担持体と転
写部材との間に位置する転写材上に像担持体表面に形成
されたトナー像が転写される。転写部材は、転写材を介
し、又は直に像担持体表面に当接するのであるが、その
両者の当接が、非画像形成動作時にも維持されたまま長
時間放置されると、像担持体表面に転写部材の当接跡が
残り、これによって異常画像が発生するおそれがある。
また、転写部材が像担持体表面に長時間当接することに
よって、その転写部材が永久歪みを起こし、その変形に
よって、像担持体から転写材へトナー像を転写するとき
の転写不良が発生することもある。従って、非画像形成
動作時には、転写部材を像担持体表面から離間させるこ
とが望ましい。2. Description of the Related Art In an image forming apparatus such as a copier, a printer, a facsimile, or a multifunction machine having at least two of these functions, a transfer material positioned between an image carrier and a transfer member is provided. The toner image formed on the surface of the image carrier is transferred to the image carrier. The transfer member abuts on the surface of the image carrier via the transfer material or directly, but if the abutment of both is left for a long time while being maintained even during the non-image forming operation, the image carrier Contact marks of the transfer member remain on the surface, which may cause an abnormal image.
Further, when the transfer member is in contact with the surface of the image carrier for a long time, the transfer member causes permanent distortion, and the deformation causes a transfer failure when the toner image is transferred from the image carrier to the transfer material. There is also. Therefore, it is desirable to separate the transfer member from the surface of the image carrier during the non-image forming operation.

【０００３】このような観点から、転写部材を像担持体
表面に対して接離させるべく、その転写部材を駆動する
モータを設けた画像形成装置が提案されている（特開平
３−１０７１８０号公報参照）。この構成によれば、転
写部材が像担持体表面に長期に亘って当接したままとな
ることを阻止でき、異常画像や転写不良の発生を阻止す
ることができる。ところが、この提案に係る画像形成装
置では、転写部材を像担持体表面に対して接離させるた
めのモータが必要となるため、画像形成装置の構造が複
雑となるばかりか、そのコストが上昇する欠点も免れな
い。[0003] From such a viewpoint, there has been proposed an image forming apparatus provided with a motor for driving the transfer member in order to move the transfer member toward and away from the surface of the image carrier (Japanese Patent Laid-Open No. 3-107180). reference). According to this configuration, it is possible to prevent the transfer member from staying in contact with the surface of the image carrier for a long period of time, and it is possible to prevent the occurrence of an abnormal image or transfer failure. However, in the image forming apparatus according to this proposal, a motor for moving the transfer member toward and away from the surface of the image carrier is required, which not only complicates the structure of the image forming apparatus but also increases its cost. There are some disadvantages.

【０００４】[0004]

【発明が解決しようとする課題】本発明は、上記認識に
基づきなされたものであって、その目的とするところ
は、専用のモータを用いることなく、像担持体部材を像
担持体表面に対して接離させることのできる冒頭に記載
した形式の画像形成装置を提供することにある。SUMMARY OF THE INVENTION The present invention has been made based on the above recognition, and an object of the present invention is to move an image carrier member to an image carrier surface without using a dedicated motor. An object of the present invention is to provide an image forming apparatus of the type described at the beginning, which can be brought into contact with and separated from the image forming apparatus.

【０００５】[0005]

【課題を解決するための手段】本発明は、上記目的を達
成するため、冒頭に記載した形式の画像形成装置におい
て、前記転写部材を像担持体表面に対して接離可能に支
持すると共に、前記像担持体が第２の方向に回転すると
き、その回転によって駆動され、像担持体表面に当接し
ていた転写部材を像担持体表面から離間させ、かつ像担
持体が第１の方向に回転したとき、その回転によって駆
動され、像担持体表面から離間していた転写部材を像担
持体表面に当接させる転写部材接離手段を設けたことを
特徴とする画像形成装置を提案する（請求項１）。SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an image forming apparatus of the type described at the beginning, wherein the transfer member is supported so as to be able to approach and separate from the surface of the image carrier. When the image carrier rotates in the second direction, the image carrier is driven by the rotation to separate the transfer member that has been in contact with the image carrier surface from the image carrier surface, and the image carrier moves in the first direction. An image forming apparatus is proposed in which a transfer member contacting / separating means is provided which, when rotated, is driven by the rotation and makes the transfer member separated from the surface of the image carrier abut on the surface of the image carrier. Claim 1).

【０００６】その際、前記転写部材接離手段が、転写部
材側に設けられていて、像担持体が第２の方向に回転し
たとき、その回転によって駆動され退避位置から作動し
て像担持体側に係合することにより、転写部材を像担持
体表面から離間させ、像担持体が第１の方向に回転した
とき、その回転によって駆動されて退避位置に戻り転写
部材を像担持体表面に当接させるカムを有していると有
利である（請求項２）。At this time, the transfer member contacting / separating means is provided on the transfer member side, and when the image carrier rotates in the second direction, it is driven by the rotation and operates from the retreat position to operate on the image carrier side. When the image carrier is rotated in the first direction, the transfer member is driven by the rotation to return to the retracted position, and the transfer member is brought into contact with the surface of the image carrier. It is advantageous to have a cam to contact (claim 2).

【０００７】また、上記請求項２に記載の画像形成装置
において、前記転写部材接離手段が、前記カムと転写部
材との間に介設され、像担持体が第１の方向に回転する
とき、その像担持体の回転をカムに伝えず、像担持体が
第２の方向に回転したとき、前記カムが像担持体側に係
合するように、像担持体の回転を前記カムに伝えるクラ
ッチを有していると有利である（請求項３）。In the image forming apparatus according to the second aspect, when the transfer member contacting / separating means is interposed between the cam and the transfer member, and the image carrier rotates in the first direction. A clutch for transmitting the rotation of the image carrier to the cam so that the cam engages with the image carrier when the image carrier rotates in the second direction without transmitting the rotation of the image carrier to the cam. Is advantageous (claim 3).

【０００８】さらに、上記請求項１乃至３のいずれかに
記載の画像形成装置において、転写部材が、伝動手段を
介して、像担持体に駆動連結され、像担持体の回転が転
写部材に伝達されて当該転写部材が回転駆動され、転写
部材が像担持体表面から離間したときも、像担持体から
転写部材に回転が伝えられるように、前記伝動手段を構
成すると有利である（請求項４）。Further, in the image forming apparatus according to any one of claims 1 to 3, the transfer member is drivingly connected to the image carrier via a transmission means, and the rotation of the image carrier is transmitted to the transfer member. When the transfer member is rotated and driven, and the transfer member is separated from the surface of the image carrier, it is advantageous to configure the transmission means so that rotation is transmitted from the image carrier to the transfer member. ).

【０００９】また、上記請求項１に記載の画像形成装置
において、前記転写部材が、像担持体表面に接離可能で
あり、かつ像担持体の回転に連動して第１方向又は第２
方向に回転する転写ローラより成り、前記転写部材接離
手段が、転写ローラに付設されたカムと、該カムと転写
ローラとの間に介設されたクラッチとを具備し、該クラ
ッチは、像担持体が第１の方向に回転し、これに連動し
て転写ローラが像担持体表面に当接しながら第１方向に
回転するとき、前記カムが退避位置に保持されるよう
に、転写ローラの回転を前記カムに伝えず、像担持体が
第２の方向に回転し、これに連動して転写ローラが第２
方向に回転するとき、前記カムが像担持体側に係合して
転写ローラが像担持体表面から離間するように、転写ロ
ーラの回転をカムに伝えるワンウェイクラッチとして構
成されていると有利である（請求項５）。Further, in the image forming apparatus according to the first aspect, the transfer member can be brought into contact with and separated from the surface of the image carrier, and the first member or the second member can be moved in conjunction with the rotation of the image carrier.
The transfer member contacting / separating means includes a cam attached to the transfer roller, and a clutch interposed between the cam and the transfer roller. When the carrier rotates in the first direction, and when the transfer roller rotates in the first direction while abutting on the surface of the image carrier, the cam is held at the retracted position. The image carrier rotates in the second direction without transmitting the rotation to the cam.
It is advantageous if the cam is engaged as a one-way clutch for transmitting the rotation of the transfer roller to the cam so that the cam is engaged with the image carrier and the transfer roller is separated from the surface of the image carrier. Claim 5).

【００１０】さらに、上記請求項５に記載の画像形成装
置において、前記転写ローラが、弾性体より成るローラ
本体と、該ローラ本体を固定支持する剛体より成るロー
ラ軸とを有し、前記カムが前記ワンウェイクラッチを介
してローラ軸に支持されていると有利である（請求項
６）。Further, in the image forming apparatus according to claim 5, the transfer roller has a roller body made of an elastic body, and a roller shaft made of a rigid body fixedly supporting the roller body. Advantageously, it is supported on the roller shaft via the one-way clutch (claim 6).

【００１１】また、上記請求項６に記載の画像形成装置
において、前記ローラ本体が像担持体表面に圧接するよ
うに、ローラ軸の軸方向各端部を加圧する加圧部材を有
していると有利である（請求項７）。The image forming apparatus according to claim 6, further comprising a pressing member for pressing each end of the roller shaft in the axial direction such that the roller body is pressed against the surface of the image carrier. (Claim 7).

【００１２】さらに、上記請求項５乃至７に記載の画像
形成装置において、前記像担持体の回転を転写ローラに
伝える伝動手段を有し、転写ローラが像担持体表面から
離間したときも、像担持体側から転写ローラに回転が伝
えられるように、前記伝動手段を構成すると有利である
（請求項８）。The image forming apparatus according to any one of claims 5 to 7, further comprising a power transmitting means for transmitting the rotation of the image carrier to a transfer roller, so that the image is transferred even when the transfer roller is separated from the surface of the image carrier. It is advantageous to configure the transmission means so that the rotation is transmitted from the carrier to the transfer roller (claim 8).

【００１３】また、上記請求項１に記載の画像形成装置
において、前記転写部材が、複数の転写部材用プーリに
巻き掛けられ、かつ像担持体表面に接離可能であり、像
担持体の回転に連動して第１方向又は第２方向に回転
し、像担持体表面に当接しながら第１方向に回転すると
き、像担持体表面のトナー像が転写される転写材を担持
して搬送する転写ベルトより成り、前記転写部材接離手
段が、前記複数の転写部材用プーリのうち、前記転写ベ
ルトを介して像担持体に対向する対向プーリに付設され
たカムと、該カムと前記対向プーリとの間に介設された
クラッチとを具備し、該クラッチは、像担持体が第１の
方向に回転し、これに連動して前記対向プーリと転写ベ
ルトが第１方向に回転するとき、前記カムが退避位置に
保持されるように対向プーリの回転を前記カムに伝え
ず、像担持体が第２の方向に回転し、これに連動して対
向プーリと転写ベルトが第２方向に回転するとき、前記
カムが像担持体側に係合して転写ベルトが像担持体表面
から離間するように、対向プーリの回転をカムに伝える
ワンウェイクラッチとして構成すると有利である（請求
項９）。Further, in the image forming apparatus according to claim 1, the transfer member is wound around a plurality of transfer member pulleys and is capable of coming into contact with and separating from the surface of the image carrier. When the image bearing member rotates in the first direction or the second direction in conjunction with the image carrier and rotates in the first direction while abutting on the surface of the image carrier, it carries and conveys a transfer material onto which the toner image on the surface of the image carrier is transferred. A transfer belt, wherein the transfer member contacting / separating means is provided on a facing pulley of the plurality of transfer member pulleys that faces the image carrier via the transfer belt; and the cam and the facing pulley. And a clutch interposed between the transfer belt and the opposing pulley and the transfer belt rotating in the first direction when the image carrier rotates in the first direction. So that the cam is held in the retracted position. When the rotation of the pulley is not transmitted to the cam, the image carrier rotates in the second direction, and the cam engages with the image carrier when the opposing pulley and the transfer belt rotate in the second direction. Advantageously, the transfer belt is configured as a one-way clutch for transmitting the rotation of the opposing pulley to the cam so that the transfer belt is separated from the surface of the image carrier.

【００１４】さらに、上記請求項９に記載の画像形成装
置において、前記像担持体側の回転を前記対向プーリに
伝える伝動手段を有し、転写ベルトが像担持体表面から
離間したときも、像担持体側から対向プーリに回転が伝
えられるように、前記伝動手段を構成すると有利である
（請求項１０）。The image forming apparatus according to claim 9, further comprising a transmission means for transmitting the rotation of the image carrier to the opposed pulley, so that the image carrier is maintained even when the transfer belt is separated from the surface of the image carrier. It is advantageous to configure the transmission means so that the rotation is transmitted from the body side to the opposing pulley (claim 10).

【００１５】また、上記請求項１に記載の画像形成装置
において、前記転写部材が、像担持体表面に接離可能で
あり、かつ像担持体の回転に連動して第１方向又は第２
方向に回転し、像担持体表面に当接しながら第１方向に
回転するとき、像担持体表面のトナー像が転写される転
写材を表面に巻き付けて搬送する転写ドラムより成り、
前記転写部材接離手段が、転写ドラムに付設されたカム
と、該カムと転写ドラムとの間に介設されたクラッチと
を具備し、該クラッチは、像担持体が第１の方向に回転
し、これに連動して転写ドラムが第１方向に回転すると
き、前記カムが退避位置に保持されるように転写ドラム
の回転を前記カムに伝えず、像担持体が第２の方向に回
転し、これに連動して転写ドラムが第２方向に回転する
とき、前記カムが像担持体側に係合して転写ドラムが像
担持体表面から離間するように、転写ドラムの回転をカ
ムに伝えるワンウェイクラッチとして構成されていると
有利である（請求項１１）。Further, in the image forming apparatus according to the first aspect, the transfer member can be brought into contact with or separated from the surface of the image carrier, and the first member or the second member can be moved in conjunction with the rotation of the image carrier.
A transfer drum that winds and transfers a transfer material onto which the toner image on the image carrier surface is transferred when rotating in the first direction while contacting the image carrier surface,
The transfer member contacting / separating means includes a cam attached to the transfer drum, and a clutch interposed between the cam and the transfer drum, wherein the clutch rotates the image carrier in a first direction. When the transfer drum rotates in the first direction in conjunction therewith, the rotation of the transfer drum is not transmitted to the cam so that the cam is held at the retracted position, and the image carrier rotates in the second direction. When the transfer drum rotates in the second direction in conjunction therewith, the rotation of the transfer drum is transmitted to the cam such that the cam engages with the image carrier and the transfer drum separates from the surface of the image carrier. Advantageously, it is configured as a one-way clutch (claim 11).

【００１６】さらに、上記請求項１１に記載の画像形成
装置において、前記像担持体側の回転を前記転写ドラム
に伝える伝動手段を有し、転写ドラムが像担持体表面か
ら離間したときも、像担持体側から転写ドラムに回転が
伝えられるように、前記伝動手段を構成すると有利であ
る（請求項１２）。The image forming apparatus according to claim 11, further comprising a power transmitting means for transmitting the rotation of the image bearing member to the transfer drum, so that the image bearing member can rotate even when the transfer drum is separated from the surface of the image bearing member. It is advantageous to configure the transmission means so that the rotation is transmitted from the body side to the transfer drum (claim 12).

【００１７】また、上記請求項５乃至１２のいずれかに
記載の画像形成装置において、前記カムが像担持体側に
係合して転写部材が像担持体表面から離間した状態で、
像担持体が第１の方向に回転したとき、カムが、像担持
体側から受ける力によって退避位置に戻り、転写部材が
像担持体表面に当接するように構成すると有利である
（請求項１３）。The image forming apparatus according to any one of claims 5 to 12, wherein the cam is engaged with the image carrier and the transfer member is separated from the surface of the image carrier.
Advantageously, when the image carrier rotates in the first direction, the cam returns to the retracted position by the force received from the image carrier side, and the transfer member comes into contact with the surface of the image carrier. .

【００１８】さらに、上記請求項２乃至１３に記載の画
像形成装置において、退避位置へ戻るカムの縁部が係合
する係合溝が像担持体側に形成されていると有利である
（請求項１４）。Further, in the image forming apparatus according to any one of the second to thirteenth aspects, it is advantageous that an engaging groove for engaging an edge of the cam returning to the retracted position is formed on the image carrier side. 14).

【００１９】また、上記請求項２乃至１４のいずれかに
記載の画像形成装置において、前記像担持体が像担持ド
ラムより成り、該像担持ドラムが第２の方向に回転した
とき、前記カムが像担持ドラムの軸方向端部に固定され
た端部材に係合して転写部材を像担持ドラム表面から離
間させるように構成すると有利である（請求項１５）。The image forming apparatus according to any one of claims 2 to 14, wherein the image bearing member comprises an image bearing drum, and when the image bearing drum rotates in the second direction, the cam is moved. It is advantageous that the transfer member is separated from the surface of the image bearing drum by engaging with an end member fixed to the axial end of the image bearing drum.

【００２０】さらに、上記請求項２乃至１４に記載の画
像形成装置において、前記像担持体が複数の像担持体用
プーリに巻き掛けられて第１又は第２の方向に回転する
像担持ベルトより成り、前記カムが、前記複数の像担持
体用プーリのうち、像担持ベルトを介して転写部材に対
向した像担持体用プーリに係合して転写部材を像担持ベ
ルト表面から離間させるように構成すると有利である
（請求項１６）。The image forming apparatus according to any one of claims 2 to 14, wherein the image carrier is wound around a plurality of image carrier pulleys and is rotated in the first or second direction. The cam is engaged with an image carrier pulley facing the transfer member via the image carrier belt among the plurality of image carrier pulleys so as to separate the transfer member from the surface of the image carrier belt. It is advantageous to configure (claim 16).

【００２１】また、上記請求項１乃至１６のいずれかに
記載の画像形成装置において、像担持体表面の転写残ト
ナーをクリーニング部材によって除去し終えた後、像担
持体が第２の方向に回転するように構成すると有利であ
る（請求項１７）。Further, in the image forming apparatus according to any one of claims 1 to 16, after the transfer residual toner on the surface of the image carrier is completely removed by the cleaning member, the image carrier rotates in the second direction. It is advantageous if it comprises so that it may carry out (claim 17).

【００２２】さらに、上記請求項１７に記載の画像形成
装置において、前記クリーニング部材が、像担持体表面
に圧接してその表面に付着する転写残トナーを掻き取る
クリーニングブレードであると有利である（請求項１
８）。Further, in the image forming apparatus according to the present invention, it is advantageous that the cleaning member is a cleaning blade which presses against the surface of the image carrier to scrape off the transfer residual toner adhered to the surface. Claim 1
8).

【００２３】また、上記請求項１７又は１８に記載の画
像形成装置において、前記像担持体が第２の方向に回転
し始め、その回転に伴って転写部材が像担持体表面から
離間し、次いで像担持体が回転を停止するまでに、像担
持体表面上の一点がその表面に沿って移動する距離が、
転写部材が像担持体表面に当接する当接点から、クリー
ニング部材が像担持体表面に当接する当接点までの像担
持体表面に沿う距離よりも短かく設定されていると有利
である（請求項１９）。Further, in the image forming apparatus according to claim 17 or 18, the image carrier starts to rotate in the second direction, and the transfer member separates from the surface of the image carrier as the image carrier rotates. By the time the image carrier stops rotating, the distance that a point on the image carrier surface moves along the surface is
It is advantageous if the distance between the contact point where the transfer member contacts the image carrier surface and the contact point where the cleaning member contacts the image carrier surface is shorter than the distance along the image carrier surface. 19).

【００２４】さらに、上記請求項１乃至１９のいずれか
に記載の画像形成装置において、像担持体を、静電潜像
が形成され、その静電潜像がトナー像として可視像化さ
れる潜像担持体として構成することもできる（請求項２
０）。Further, in the image forming apparatus according to any one of claims 1 to 19, an electrostatic latent image is formed on the image carrier, and the electrostatic latent image is visualized as a toner image. It may be configured as a latent image carrier.
0).

【００２５】同様に、上記請求項１乃至１９のいずれか
に記載の画像形成装置において、像担持体を、潜像担持
体からトナーを転写される中間転写体として構成するこ
ともできる（請求項２１）。Similarly, in the image forming apparatus according to any one of claims 1 to 19, the image carrier may be configured as an intermediate transfer member to which toner is transferred from the latent image carrier. 21).

【００２６】[0026]

【発明の実施の形態】以下、本発明の実施形態例を図面
に従って詳細に説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

【００２７】図１は本発明一実施形態例の画像形成装置
の内部を正面側から示した概略断面図であり、その画像
形成装置本体１には作像ユニット２が着脱可能に装着さ
れている。ここに示した画像形成装置は複写機として構
成され、この複写機にプリンタやファクシミリなどの機
能をもたせることもできる。作像ユニット２は画像形成
装置本体１の手前側から画像形成装置本体に対して着脱
される。FIG. 1 is a schematic sectional view showing the inside of an image forming apparatus according to an embodiment of the present invention from the front side. An image forming unit 2 is detachably mounted on the main body 1 of the image forming apparatus. . The image forming apparatus shown here is configured as a copying machine, and the copying machine may have functions such as a printer and a facsimile. The image forming unit 2 is attached to and detached from the image forming apparatus main body from the near side of the image forming apparatus main body 1.

【００２８】図２は作像ユニット２と転写ユニット３と
を正面側から見たときの拡大断面図であり、この図と図
１に示すように、作像ユニット２はユニットケース４を
有し、このケース４の内部には像担持体の一例であるド
ラム状の感光体５と、帯電装置の一例である帯電ローラ
６がそれぞれ回転自在に組付けられている。FIG. 2 is an enlarged sectional view of the image forming unit 2 and the transfer unit 3 as viewed from the front side. As shown in FIG. 2 and FIG. 1, the image forming unit 2 has a unit case 4. Inside the case 4, a drum-shaped photoconductor 5 as an example of an image carrier and a charging roller 6 as an example of a charging device are rotatably mounted.

【００２９】画像形成動作時に感光体５は図示していな
い駆動装置によって図２に実線矢印で示した時計方向に
回転駆動され、このとき除電光Ｌ１によって感光体表面
が基準電位に除電される。このときの感光体の回転方向
が第１の方向である。帯電ローラ６は感光体５の表面に
圧接しながら従動回転し、感光体表面を所定の極性に一
様に帯電する。このように帯電された感光体５の表面部
分には、原稿からの光像又は光変調されたレーザＬ２が
照射され、これによって感光体５上に所定の静電潜像が
形成される。At the time of the image forming operation, the photosensitive member 5 is driven to rotate clockwise as indicated by a solid arrow in FIG. 2 by a driving device (not shown). At this time, the photosensitive member surface is neutralized by the neutralizing light L1 to the reference potential. The rotation direction of the photoconductor at this time is the first direction. The charging roller 6 is driven to rotate while being in pressure contact with the surface of the photoreceptor 5, and uniformly charges the surface of the photoreceptor to a predetermined polarity. The surface of the photoconductor 5 charged in this way is irradiated with a light image from a document or a light-modulated laser L2, whereby a predetermined electrostatic latent image is formed on the photoconductor 5.

【００３０】一方、ユニットケース４には、図２に示す
ように現像装置７の現像ローラ８が回転自在に支持さ
れ、ユニットケース４の一部によって構成された現像ケ
ース９には、現像剤Ｄが収容され、この現像剤Ｄは、反
時計方向に回転駆動される現像ローラ８上に担持されて
搬送される。かかる搬送現像剤が感光体５と現像ローラ
８との間に至ったとき、現像剤中の帯電したトナーが感
光体５に形成された静電潜像に静電的に移行し、その潜
像がトナー像として可視像化される。On the other hand, a developing roller 8 of a developing device 7 is rotatably supported on the unit case 4 as shown in FIG. 2, and a developing agent 9 is formed on a developing case 9 constituted by a part of the unit case 4. The developer D is carried and conveyed on a developing roller 8 which is driven to rotate counterclockwise. When the transported developer reaches between the photoconductor 5 and the developing roller 8, the charged toner in the developer is electrostatically transferred to an electrostatic latent image formed on the photoconductor 5, and the latent image is transferred. Is visualized as a toner image.

【００３１】転写ユニット３は、転写部材の一例である
転写ローラ１１と、除電装置１２と、これらを保持する
保持体１３とを有し、転写ローラ１１は感光体５に対し
て平行に延びている。除電装置１２は、感光体５に対し
て平行に延びる除電針１４と、これを保持するホルダ１
５とを有している。画像形成動作時に転写ローラ１１は
感光体５の表面に対向して圧接した作動位置を占め、反
時計方向に回転駆動される。The transfer unit 3 has a transfer roller 11, which is an example of a transfer member, a charge eliminator 12, and a holder 13 for holding the same. The transfer roller 11 extends in parallel with the photosensitive member 5. I have. The static eliminator 12 includes a static elimination needle 14 extending in parallel with the photoconductor 5 and a holder 1 for holding the needle.
5 is provided. During the image forming operation, the transfer roller 11 occupies the operating position pressed against the surface of the photoconductor 5 and is driven to rotate counterclockwise.

【００３２】一方、図１に示した複数の給紙装置１６，
１７，１８，１９のうちの選択された給紙装置から、転
写材の一例である転写紙Ｐが感光体５と転写ローラ１１
の間の転写領域２０へ矢印Ａで示すように搬送される。
そして、転写紙Ｐが転写領域２０を通過するとき、転写
ローラ１１に印加された転写電圧の作用によって、感光
体５の表面に形成されたトナー像が転写紙Ｐ上に転写さ
れる。転写ローラ１１は、転写紙Ｐを介して感光体５の
表面に当接しながら回転し、このときこの転写ローラ１
１には、感光体５上のトナーと逆極性の転写電圧が印加
される。On the other hand, the plurality of paper feeders 16 shown in FIG.
Transfer paper P, which is an example of a transfer material, is supplied from a selected one of the paper feeders 17, 18 and 19 to the photoconductor 5 and the transfer roller 11.
Are transported to the transfer area 20 as indicated by the arrow A.
When the transfer paper P passes through the transfer area 20, the toner image formed on the surface of the photoconductor 5 is transferred onto the transfer paper P by the action of the transfer voltage applied to the transfer roller 11. The transfer roller 11 rotates while abutting on the surface of the photoconductor 5 via the transfer paper P.
1, a transfer voltage having a polarity opposite to that of the toner on the photoconductor 5 is applied.

【００３３】一方、除電装置１２の除電針１４から感光
体５の表面に向けて発生する放電の作用によって、転写
紙Ｐは感光体５から分離される。感光体５を離れて矢印
Ｂ方向に搬送される転写紙Ｐは、定着装置１２１を通
り、このとき転写紙上のトナー像が熱と圧力の作用によ
って転写紙上に定着される。次いで、この転写紙Ｐは、
トナー像より成る記録画像の形成されたコピー紙として
画像形成装置本体外のトレイ１２２上に排出される。On the other hand, the transfer paper P is separated from the photoreceptor 5 by the action of a discharge generated from the charge eliminating needle 14 of the charge eliminating device 12 toward the surface of the photoreceptor 5. The transfer paper P conveyed in the direction of arrow B leaving the photoconductor 5 passes through the fixing device 121, and at this time, the toner image on the transfer paper is fixed on the transfer paper by the action of heat and pressure. Next, this transfer paper P is
The sheet is discharged onto a tray 122 outside the main body of the image forming apparatus as a copy sheet on which a recording image formed of a toner image is formed.

【００３４】トナー像転写後に感光体５上に残留してい
るトナーは、クリーニング装置２３のクリーニング部材
２４によって感光体表面から除去され、ユニットケース
４の一部によって構成されたクリーニングケース２５内
に落下する。The toner remaining on the photoreceptor 5 after the transfer of the toner image is removed from the surface of the photoreceptor by a cleaning member 24 of a cleaning device 23 and falls into a cleaning case 25 constituted by a part of the unit case 4. I do.

【００３５】図３は、図１及び図２に示した感光体５と
転写ローラ１１とを示す斜視図であり、感光体５の軸方
向奥側の端部と手前側の端部には、一般にフランジと称
せられている端部材２１，２２が固定され、その各端部
材２１，２２の中心部に位置する軸部２６，２７が、ユ
ニットケース４（図２）に回転自在に支持されている。
このように本例では感光体５がユニットケース４を介し
て画像形成装置本体に支持されているが、感光体５を直
に画像形成装置本体に回転自在に支持することもでき
る。FIG. 3 is a perspective view showing the photoreceptor 5 and the transfer roller 11 shown in FIGS. 1 and 2. The photoreceptor 5 has an axially deep end and a near end. End members 21 and 22 generally called flanges are fixed, and shaft portions 26 and 27 located at the center of each end member 21 and 22 are rotatably supported by the unit case 4 (FIG. 2). I have.
As described above, in this embodiment, the photoconductor 5 is supported by the image forming apparatus main body via the unit case 4, but the photoconductor 5 can be directly rotatably supported by the image forming apparatus main body.

【００３６】転写ローラ１１は、感光体５に対して平行
に位置し、導電性の剛体より成るローラ軸２８と、この
ローラ軸２８に固定支持された弾性体より成る円筒状の
ローラ本体２９より成り、このローラ本体２９は、例え
ば１０7乃至１０9Ωcm程の抵抗率の発泡体やゴムなどに
よって構成される。ローラ軸２８の軸方向各端部は、こ
れらに相対回転自在に嵌合したすべり軸受３０，３１に
それぞれ支持され、これらの軸受３０，３１は、図２に
示すように保持体１３の凹溝状の収容部３２に、感光体
５に対して接近又は離隔する方向に摺動自在に嵌合して
いる。また、各軸受３０，３１と保持体１３の収容部３
２の底壁との間には、加圧部材の一例である圧縮スプリ
ング３３，３４が圧装され、これによって転写ローラ１
１のローラ本体２９が感光体５の表面に圧接する。圧縮
スプリング３３，３４を圧縮させれば、転写ローラ１１
を感光体５の表面から離間させることができる。本例で
は転写ローラ１１が保持体１３を介して画像形成装置本
体に支持されているが、転写ローラ１１を直に画像形成
装置本体に回転自在に支持することもできる。The transfer roller 11 includes a roller shaft 28 made of a conductive rigid body and a cylindrical roller body 29 made of an elastic body fixedly supported on the roller shaft 28 and positioned in parallel with the photoreceptor 5. The roller body 29 is made of, for example, foam or rubber having a resistivity of about 10 7 to 10 9 Ωcm. Each end of the roller shaft 28 in the axial direction is supported by slide bearings 30 and 31 respectively rotatably fitted thereto, and these bearings 30 and 31 are formed in the grooves of the holding body 13 as shown in FIG. It is slidably fitted in the accommodating portion 32 in a direction approaching or separating from the photoconductor 5. In addition, each bearing 30, 31 and the accommodation portion 3 of the holding body 13
The compression rollers 33 and 34, which are examples of a pressure member, are press-fitted between the transfer roller 1 and the bottom wall of the transfer roller 1.
The first roller body 29 is pressed against the surface of the photoconductor 5. If the compression springs 33 and 34 are compressed, the transfer roller 11
Can be separated from the surface of the photoconductor 5. In this embodiment, the transfer roller 11 is supported by the main body of the image forming apparatus via the holding member 13. However, the transfer roller 11 can be directly rotatably supported by the main body of the image forming apparatus.

【００３７】感光体５の奥側端部に固定された端部材２
１の周面にはギア３５が形成され、このギアが画像形成
装置本体側に支持された駆動ギア（図示せず）に噛み合
い、これらのギアを介して図示していないモータによっ
て、感光体５が第１の方向、すなわち図２及び図３に実
線矢印で示した方向に回転駆動される。また感光体５
は、後述するように、上述のギアとモータとによって、
第１の方向と逆の第２の方向、すなわち図２及び図３に
破線矢印で示した方向にも回転することができる。End member 2 fixed to the rear end of photoconductor 5
A gear 35 is formed on a peripheral surface of the photoconductor 5. The gear 35 meshes with a driving gear (not shown) supported on the image forming apparatus main body side, and a motor (not shown) drives the photosensitive member 5 via these gears. Are driven to rotate in a first direction, that is, a direction indicated by a solid arrow in FIGS. 2 and 3. Photoconductor 5
As described later, by the above-described gear and motor,
It is also possible to rotate in a second direction opposite to the first direction, that is to say in the direction indicated by the dashed arrows in FIGS.

【００３８】また感光体５の手前側に固定された端部材
２２の周面にもギア３６が形成され、このギア３６は、
転写ローラ１１のローラ軸２８に固設されたギア３７に
噛み合っており、画像形成動作時に感光体５が前述の如
く第１の方向に回転すると、その回転は、ギア３６，３
７より成る伝動手段を介して転写ローラ１１に伝えられ
る。このときの転写ローラ１１の回転方向は、その転写
ローラ１１と感光体５との当接部において、両者の表面
が同一方向に移動する向き、すなわち感光体５の回転方
向に対して順方向の向きとなる。感光体５が第１の方向
に回転したとき、これに連動して回転する転写ローラ１
１の回転方向を第１方向、感光体５が第２の方向に回転
したとき、これに連動して回転する転写ローラ１１の回
転方向を第２方向と称することにする。A gear 36 is also formed on the peripheral surface of the end member 22 fixed to the front side of the photoreceptor 5.
When the photoreceptor 5 rotates in the first direction as described above during the image forming operation, the rotation is performed by the gears 36 and 3.
The power is transmitted to the transfer roller 11 via a power transmission means composed of the transfer roller 7. At this time, the rotation direction of the transfer roller 11 is a direction in which the surfaces of the transfer roller 11 and the photoconductor 5 move in the same direction at the contact portion between the transfer roller 11 and the photoconductor 5, that is, a forward direction with respect to the rotation direction of the photoconductor 5. Orientation. When the photoconductor 5 rotates in the first direction, the transfer roller 1 rotates in conjunction with the rotation.
The rotation direction of the transfer roller 11 that rotates when the photosensitive member 5 rotates in the first direction and the photosensitive member 5 rotates in the second direction is referred to as the second direction.

【００３９】上述のように、本例の画像形成装置は、第
１の方向に回転駆動されつつ表面にトナー像を形成され
る感光体５より成る像担持体と、転写紙Ｐより成る転写
材を介して像担持体表面に当接しながら像担持体表面に
形成されたトナー像を転写材に転写するための転写ロー
ラ１１として構成された転写部材と、トナー像転写後の
像担持体表面に付着する転写残トナーを像担持体表面か
ら除去して当該像担持体表面を清掃するクリーニング部
材２４とを具備している。As described above, the image forming apparatus according to the present embodiment includes an image carrier composed of the photoreceptor 5 on which a toner image is formed while being rotated in the first direction, and a transfer material composed of the transfer paper P. A transfer member configured as a transfer roller 11 for transferring a toner image formed on the image carrier surface to a transfer material while contacting the image carrier surface via A cleaning member 24 for removing the transfer residual toner adhered from the surface of the image carrier and cleaning the surface of the image carrier.

【００４０】画像形成動作を終了すると、感光体５は回
転を停止する。すなわち、感光体表面の転写残トナーを
クリーニング部材２４が除去し終えた直後、又はその所
定時間後に感光体５は停止する。ここで本例の画像形成
装置においては、感光体より成る像担持体の表面の転写
残トナーをクリーニング部材２４によって除去し終えた
後、その像担持体が第２の方向に回転するように構成さ
れている。感光体５が図２及び図３に破線矢印で示す第
２の方向に所定の角度だけ回転するのである。このよう
に本例の画像形成装置では、感光体５より成る像担持体
が、前述の第１の方向とは逆の第２の方向にも回転可能
となっている。When the image forming operation is completed, the rotation of the photosensitive member 5 is stopped. That is, the photosensitive member 5 stops immediately after the cleaning member 24 has finished removing the transfer residual toner on the surface of the photosensitive member or after a predetermined time. Here, in the image forming apparatus of the present embodiment, after the transfer residual toner on the surface of the image carrier made of the photoconductor has been removed by the cleaning member 24, the image carrier is rotated in the second direction. Have been. The photoreceptor 5 rotates by a predetermined angle in the second direction indicated by the broken arrow in FIGS. As described above, in the image forming apparatus according to the present embodiment, the image carrier including the photoconductor 5 is also rotatable in the second direction opposite to the above-described first direction.

【００４１】クリーニング部材２４は、感光体表面に付
着した転写残トナーを除去するものであるが、このよう
な清掃作業が行われるとき、そのクリーニング部材２４
が感光体５の表面に当接した部分に、トナーや紙粉が溜
ることがある。これを放置したまま、次の画像形成動作
を行うと、感光体に対するクリーニング不良が発生し、
次に形成されるトナー像に地汚れが発生するおそれがあ
る。特に、クリーニング部材２４が、図２に示すよう
に、像担持体表面に先端エッジ部を圧接してその表面に
付着する転写残トナーを掻き取るクリーニングブレード
であるときは、その先端エッジ部の部位にトナーや紙粉
が溜りやすい。The cleaning member 24 removes transfer residual toner adhering to the surface of the photosensitive member. When such a cleaning operation is performed, the cleaning member 24 is removed.
May accumulate on the surface of the photoreceptor 5 where toner and paper dust accumulate. If the next image forming operation is carried out while leaving this as it is, cleaning failure occurs on the photoconductor,
The toner image formed next may be stained. In particular, as shown in FIG. 2, when the cleaning member 24 is a cleaning blade that presses the leading edge to the surface of the image carrier to scrape off the untransferred toner adhering to the surface, the portion of the leading edge is used. Easily accumulates toner and paper dust.

【００４２】そこで、クリーニング部材２４によって感
光体５上の転写残トナーを除去し終えた後、感光体５を
所定角度だけ第２の方向に回転させ、クリーニング部材
２４の先端エッジ部に溜ったトナーや紙粉をそのエッジ
部から排出し、次の画像形成動作時に、感光体に付着し
た紙粉やトナーをクリーニング部材２４によって除去す
るのである。Then, after removing the transfer residual toner on the photosensitive member 5 by the cleaning member 24, the photosensitive member 5 is rotated by a predetermined angle in the second direction, and the toner collected on the leading edge of the cleaning member 24 is removed. Paper dust and paper dust are discharged from the edge portion, and the paper dust and toner attached to the photoconductor are removed by the cleaning member 24 at the time of the next image forming operation.

【００４３】上述した構成自体は従来より公知であり、
またこの構成は後に説明する各実施形態例にも採用され
るものである。The above configuration itself is conventionally known,
This configuration is also adopted in each embodiment described later.

【００４４】ところで、感光体５が停止した後も、転写
ローラ１１が感光体５の表面に当接したままであると、
先にも説明したように、感光体表面に転写ローラの当接
跡が残って異常画像の発生原因となったり、転写ローラ
１１のローラ本体２９に永久歪みを生じ、転写不良が発
生する原因となる。そこで従来は、感光体が停止した後
の非画像形成動作時に、転写ローラが感光体の表面から
離間するように、その転写ローラをモータによって駆動
していた。ところが、この構成によると画像形成装置の
構造が複雑化し、またそのコストが上昇する。By the way, if the transfer roller 11 is kept in contact with the surface of the photosensitive member 5 even after the photosensitive member 5 stops,
As described above, contact marks of the transfer roller remain on the surface of the photoreceptor and cause an abnormal image, or cause permanent deformation of the roller body 29 of the transfer roller 11 and cause transfer failure. Become. Therefore, conventionally, during a non-image forming operation after the photosensitive member is stopped, the transfer roller has been driven by a motor such that the transfer roller is separated from the surface of the photosensitive member. However, according to this configuration, the structure of the image forming apparatus is complicated, and the cost is increased.

【００４５】そこで本例の画像形成装置においては、前
述の如く、転写ローラ１１より成る像担持体部材が、感
光体５より成る像担持体の表面に対して接離可能に支持
されていると共に、像担持体が第２の方向に回転すると
き、その回転を駆動源として、転写部材を像担持体表面
から離間させ、再び像担持体が第１の方向に回転したと
きも、その回転を駆動源として、転写部材を像担持体表
面に当接させる転写部材接離手段が設けられている。そ
の具体的構成は以下の通りである。Therefore, in the image forming apparatus of this embodiment, as described above, the image carrier member composed of the transfer roller 11 is supported so as to be able to contact and separate from the surface of the image carrier composed of the photoreceptor 5. When the image carrier rotates in the second direction, the rotation is used as a drive source to separate the transfer member from the surface of the image carrier, and when the image carrier rotates again in the first direction, the rotation is also performed. A transfer member contacting / separating means for bringing the transfer member into contact with the surface of the image carrier is provided as a driving source. The specific configuration is as follows.

【００４６】図３に示すように、転写ローラ１１のロー
ラ軸２８には、カム３８が付設され、そのカム３８とロ
ーラ軸２８との間にワンウェイクラッチ３９が介設され
ている。このワンウェイクラッチ３９は、画像形成動作
時に感光体５が第１の方向に回転し、これに連動して、
転写ローラ１１が、感光体表面に当接しながら第１方向
に回転しているとき、そのカム３８が、図３及び図４に
示すように、感光体５の回転を阻害しない退避位置に保
持されるように、そのローラ軸２８の回転がカム３８に
伝えられず、画像形成動作を終え、感光体５が第２の方
向に回転するときは、第２方向に回転する転写ローラ１
１のローラ軸２８の回転がカム３８に伝えられるように
構成されている。このようにしてカム３８が回転する
と、当該カム３８は、図５に示す如く感光体５の側の端
部材２２に係合し、これによって転写ローラ１１は、ス
プリング３３，３４の作用に抗して、感光体５の表面か
ら離間する。ローラ軸２８の中心からカム３８の先端ま
での長さが、転写ローラ１１の半径よりも大きく設定さ
れ、カム３８の先端が図５に示すように感光体５の側に
係合することによって、転写ローラ１１が感光体表面か
ら離れるのである。As shown in FIG. 3, a cam 38 is attached to the roller shaft 28 of the transfer roller 11, and a one-way clutch 39 is interposed between the cam 38 and the roller shaft 28. The one-way clutch 39 rotates the photoconductor 5 in the first direction during the image forming operation,
When the transfer roller 11 is rotating in the first direction while abutting on the surface of the photoreceptor, the cam 38 is held at a retracted position that does not hinder the rotation of the photoreceptor 5 as shown in FIGS. As described above, when the rotation of the roller shaft 28 is not transmitted to the cam 38 and the image forming operation is completed and the photosensitive member 5 rotates in the second direction, the transfer roller 1 rotating in the second direction
The rotation of one roller shaft 28 is transmitted to the cam 38. When the cam 38 rotates in this manner, the cam 38 engages with the end member 22 on the side of the photoconductor 5 as shown in FIG. 5, whereby the transfer roller 11 opposes the action of the springs 33 and 34. To separate from the surface of the photoconductor 5. The length from the center of the roller shaft 28 to the tip of the cam 38 is set to be larger than the radius of the transfer roller 11, and the tip of the cam 38 engages with the photoconductor 5 side as shown in FIG. This is because the transfer roller 11 is separated from the photoconductor surface.

【００４７】このように転写ローラ１１が感光体表面か
ら離れたところで、感光体５の第２の方向への回転が停
止し、転写ローラ１１が感光体表面から離れた状態で画
像形成装置が作動を停止する。このように、画像形成装
置の停止時に転写ローラ１１が感光体表面に当接するこ
とはないため、感光体表面に転写ローラの当接跡が残さ
れたり、転写ローラ１１に局部的な外力が長い時間作用
してこれが永久歪みを起こす不具合を阻止できる。As described above, when the transfer roller 11 is separated from the photosensitive member surface, the rotation of the photosensitive member 5 in the second direction is stopped, and the image forming apparatus is operated with the transfer roller 11 separated from the photosensitive member surface. To stop. As described above, since the transfer roller 11 does not come into contact with the surface of the photoconductor when the image forming apparatus is stopped, the contact mark of the transfer roller is left on the surface of the photoconductor, and the local external force on the transfer roller 11 is long. The effect of time action can be prevented from causing permanent distortion.

【００４８】画像形成装置の電源がオンされ、画像形成
動作が開始されると、感光体５は図５における時計方
向、すなわち第１の方向に回転する。このときの感光体
５の回転がギア３６，３７を介して転写ローラ１１のロ
ーラ軸２８に伝えられ、ローラ軸２８が第１方向、すな
わち図５における反時計方向に回転する。このときのロ
ーラ軸２８の回転はカム３８に伝えられないが、カム２
８は感光体５と一体の端部材２２に係合しているので、
両者の間の摩擦力によって、カム３８は図４に示した退
避位置、すなわち感光体５の回転を阻害しない位置に回
転して静止する。これによって、転写ローラ１１は、ス
プリング３３，３４による加圧作用によって感光体５の
表面に圧接する。このように、画像形成動作の開始に伴
って転写ローラ１１は支障なく感光体５に当接し、前述
のように転写紙Ｐ上に感光体表面のトナー像を転写する
用をなす。When the power of the image forming apparatus is turned on and the image forming operation is started, the photosensitive member 5 rotates clockwise in FIG. 5, that is, in the first direction. The rotation of the photoconductor 5 at this time is transmitted to the roller shaft 28 of the transfer roller 11 via the gears 36 and 37, and the roller shaft 28 rotates in the first direction, that is, the counterclockwise direction in FIG. The rotation of the roller shaft 28 at this time is not transmitted to the cam 38,
8 is engaged with the end member 22 integral with the photoreceptor 5,
Due to the frictional force between the two, the cam 38 rotates to the retracted position shown in FIG. As a result, the transfer roller 11 is pressed against the surface of the photoconductor 5 by the pressing action of the springs 33 and 34. In this manner, the transfer roller 11 abuts the photoconductor 5 without any trouble at the start of the image forming operation, and transfers the toner image on the photoconductor surface onto the transfer paper P as described above.

【００４９】カム３８が図５に示したように感光体５の
側の端部材２２に係合し、転写ローラ１１が感光体５の
表面から離れたときも、感光体５の側のギア３６と転写
ローラ１１の側のギア３７は、互いに噛み合った状態を
維持できるように、両ギア３６，３７の中心軸間距離が
設定されている。これにより、感光体５の第２の方向へ
の回転によって確実にカム３８を感光体側に係合させる
ことができ、感光体５の第１の方向への回転開始に伴っ
て、その回転を支障なく転写ローラ１１に伝達し、これ
を回転駆動することができる。When the cam 38 engages with the end member 22 on the side of the photosensitive member 5 as shown in FIG. 5 and the transfer roller 11 is separated from the surface of the photosensitive member 5, the gear 36 on the side of the photosensitive member 5 The distance between the central axes of the two gears 36 and 37 is set so that the gear 37 and the gear 37 on the side of the transfer roller 11 can be maintained in a state of meshing with each other. Accordingly, the cam 38 can be reliably engaged with the photoconductor by the rotation of the photoconductor 5 in the second direction, and the rotation of the cam 38 is hindered when the rotation of the photoconductor 5 in the first direction starts. The rotation can be transmitted to the transfer roller 11 and rotated.

【００５０】以上のように、上述した転写部材接離手段
は、像担持体が第２の方向に回転するとき、その回転に
よって駆動され、像担持体表面に当接していた転写部材
を像担持体表面から離間させ、かつ像担持体が第１の方
向に回転したとき、その回転によって駆動され、像担持
体表面から離間していた転写部材を像担持体表面に当接
させるように構成されている。As described above, the transfer member contacting / separating means is driven by the rotation of the image carrier when the image carrier rotates in the second direction, and transfers the transfer member, which has been in contact with the surface of the image carrier, to the image carrier. When the image carrier is rotated in the first direction while being separated from the body surface, the image carrier is driven by the rotation, and the transfer member that has been separated from the image carrier surface is brought into contact with the image carrier surface. ing.

【００５１】しかも、この転写部材接離手段は、転写部
材側に設けられていて、像担持体が第２の方向に回転し
たとき、その回転によって駆動されて退避位置から作動
して像担持体側に係合することにより、転写部材を像担
持体表面から離間させ、像担持体が第１の方向に回転し
たとき、その回転によって駆動されて退避位置に戻り、
転写部材を像担持体表面に当接させるカム３８を有して
いる。Further, the transfer member contacting / separating means is provided on the transfer member side, and when the image carrier rotates in the second direction, is driven by the rotation and operates from the retracted position to operate from the image carrier side. By engaging with, the transfer member is separated from the surface of the image carrier, and when the image carrier rotates in the first direction, the image carrier is driven by the rotation to return to the retracted position,
There is a cam 38 for bringing the transfer member into contact with the surface of the image carrier.

【００５２】さらに、この転写部材接離手段は、上記カ
ム３８と転写部材との間に介設され、像担持体が第１の
方向に回転するとき、その像担持体の回転をカム３８に
伝えず、像担持体が第２の方向に回転したとき、カム３
８が像担持体側に係合するように、像担持体の回転を前
記カム３８に伝えるクラッチ３９を有している。Further, the transfer member contacting / separating means is provided between the cam 38 and the transfer member. When the image carrier rotates in the first direction, the rotation of the image carrier is transmitted to the cam 38. When the image carrier rotates in the second direction without transmitting,
A clutch 39 for transmitting the rotation of the image carrier to the cam 38 so that the clutch 8 engages with the image carrier.

【００５３】しかも、転写部材が、ギア３６，３７より
成る伝動手段を介して、像担持体に駆動連結され、像担
持体の回転が転写部材に伝達されて当該転写部材が回転
駆動され、転写部材が像担持体表面から離間したとき
も、像担持体から転写部材に回転が伝えられるように伝
動手段が構成されている。これにより、カム３８を確実
に像担持体側に係合させ、また像担持体が第１の方向へ
回転を開始したとき、転写部材を確実に所定の方向（第
１方向）に回転させることができる。Further, the transfer member is drive-coupled to the image carrier via transmission means including gears 36 and 37, and the rotation of the image carrier is transmitted to the transfer member, whereby the transfer member is driven to rotate and the transfer member is rotated. The transmission means is configured to transmit the rotation from the image carrier to the transfer member even when the member is separated from the surface of the image carrier. This ensures that the cam 38 is engaged with the image carrier, and that when the image carrier starts rotating in the first direction, the transfer member is surely rotated in the predetermined direction (first direction). it can.

【００５４】また、本例の画像形成装置において、転写
部材が、像担持体表面に接離可能であり、かつ像担持体
の回転に連動して第１方向又は第２方向に回転する転写
ローラ１１より成り、転写部材接離手段が、転写ローラ
１１に付設されたカム３８と、該カム３８と転写ローラ
１１との間に介設されたクラッチ３９とを具備し、該ク
ラッチは、像担持体が第１の方向に回転し、これに連動
して転写ローラ１１が像担持体表面に当接しながら第１
方向に回転するとき、カム３８が退避位置に保持される
ように、転写ローラ１１の回転をカム３８に伝えず、像
担持体が第２の方向に回転し、これに連動して転写ロー
ラ１１が第２方向に回転するとき、カム３８が像担持体
側に係合して転写ローラ１１が像担持体表面から離間す
るように、転写ローラ１１の回転をカム３８に伝えるワ
ンウェイクラッチ３７として構成されている。Further, in the image forming apparatus of the present embodiment, the transfer roller is capable of coming into contact with and separating from the surface of the image carrier and rotating in the first direction or the second direction in conjunction with the rotation of the image carrier. The transfer member contacting / separating means includes a cam 38 attached to the transfer roller 11 and a clutch 39 interposed between the cam 38 and the transfer roller 11, and the clutch is provided with an image bearing member. The body rotates in a first direction, and in conjunction with this, the transfer roller 11
When the image carrier rotates in the second direction, the rotation of the transfer roller 11 is not transmitted to the cam 38 so that the cam 38 is held at the retracted position, and the image carrier rotates in the second direction. Is configured as a one-way clutch 37 that transmits the rotation of the transfer roller 11 to the cam 38 so that the cam 38 engages with the image carrier side and separates the transfer roller 11 from the surface of the image carrier when the roller rotates in the second direction. ing.

【００５５】さらに、本例の画像形成装置においては、
転写ローラ１１が、弾性体より成るローラ本体２９と、
該ローラ本体２９を固定支持する剛体より成るローラ軸
２８とを有していて、前述のカム３８がワンウェイクラ
ッチ３９を介してローラ軸２８に支持されている。Further, in the image forming apparatus of this embodiment,
A transfer roller 11 having a roller body 29 made of an elastic material;
And a roller shaft 28 made of a rigid body for fixedly supporting the roller body 29. The cam 38 is supported by the roller shaft 28 via a one-way clutch 39.

【００５６】また、本例の画像形成装置では、転写ロー
ラ１１のローラ本体２９が像担持体表面に圧接するよう
に、ローラ軸２８の軸方向各端部を加圧するスプリング
３３，３４より成る加圧部材を有しており、これによっ
て画像形成動作時に、転写ローラ１１を感光体５の表面
に均一な圧力で押圧させることができ、転写紙Ｐ上に高
品質なトナー像を転写することができる。In the image forming apparatus of this embodiment, the springs 33 and 34 press the axial ends of the roller shaft 28 so that the roller body 29 of the transfer roller 11 is pressed against the surface of the image carrier. The transfer roller 11 can be pressed against the surface of the photoreceptor 5 with a uniform pressure during the image forming operation, so that a high-quality toner image can be transferred onto the transfer paper P. it can.

【００５７】さらに、本例の画像形成装置は、像担持体
の回転を転写ローラ１１に伝えるギア３６，３７より成
る伝動手段を有し、転写ローラ１１が像担持体表面から
離間したときも、像担持体側から転写ローラ１１に回転
が伝えられるように、前記伝動手段が構成されている。Further, the image forming apparatus of this embodiment has a transmission means comprising gears 36 and 37 for transmitting the rotation of the image carrier to the transfer roller 11, and when the transfer roller 11 is separated from the surface of the image carrier. The transmission means is configured so that rotation is transmitted from the image carrier side to the transfer roller 11.

【００５８】また、本例の画像形成装置においては、先
に説明したように、カムが像担持体側に係合して転写部
材が像担持体表面から離間した状態で、像担持体が第１
の方向に回転したとき、カムが、像担持体側から受ける
力によって退避位置に戻り、転写部材が像担持体表面に
当接する。かかる構成は、後述する各実施形態例におい
ても同様である。In the image forming apparatus of this embodiment, as described above, the image carrier is moved to the first position with the cam engaged with the image carrier and the transfer member being separated from the surface of the image carrier.
When the cam rotates in the direction of, the cam returns to the retracted position by the force received from the image carrier, and the transfer member contacts the surface of the image carrier. Such a configuration is the same in each embodiment described later.

【００５９】さらに、本例の画像形成装置では、像担持
体がトナー像を担持するドラムにより構成されている。
すなわち、像担持体が像担持ドラムより成り、この像担
持ドラムが第２の方向に回転したとき、カム３８が像担
持ドラムの軸方向端部に固定された端部材２２に係合し
て転写部材を像担持ドラム表面から離間させるように構
成されている。この構成も、像担持体が像担持ドラムよ
り成る後述の画像形成装置に適用できるものである。Further, in the image forming apparatus of the present embodiment, the image carrier is constituted by a drum for carrying a toner image.
That is, when the image bearing member is formed of an image bearing drum, and the image bearing drum rotates in the second direction, the cam 38 engages with the end member 22 fixed to the axial end of the image bearing drum to transfer the image. The member is configured to be separated from the surface of the image bearing drum. This configuration can also be applied to an image forming apparatus described below in which the image carrier includes an image bearing drum.

【００６０】また、図３に示すように、感光体側の端部
材２２には、その周方向に配列された多数の係合溝４０
が形成されており、これらの係合溝４０はカム３８の先
端に対峙する位置に設けられている。今、カム３８が、
図５に示すように、感光体５の側の端部材２２に係合し
た状態から、感光体５が第１の回転方向に回転を開始す
ると、カム３８はその端部材２２との摩擦力によって図
４に示した退避位置へ回動する。このとき、端部材２２
に形成されたいずれかの係合溝３０に、カム３８の先端
側のコーナエッジ部３８Ａが係合し、これによって端部
材２２とカム３８の係合力が高められ、カム３８は確実
に図４に示した退避位置に回動することができる。As shown in FIG. 3, the end member 22 on the photoreceptor side has a plurality of engagement grooves 40 arranged in the circumferential direction thereof.
These engagement grooves 40 are provided at positions facing the tip of the cam 38. Now, the cam 38
As shown in FIG. 5, when the photoconductor 5 starts rotating in the first rotation direction from the state in which the cam 38 is engaged with the end member 22 on the side of the photoconductor 5, the cam 38 is moved by the frictional force with the end member 22. It rotates to the retracted position shown in FIG. At this time, the end member 22
The engaging edge 30A of the distal end of the cam 38 is engaged with one of the engaging grooves 30 formed in the cam 38, whereby the engaging force between the end member 22 and the cam 38 is increased. Can be turned to the retracted position shown in FIG.

【００６１】このように、本例の画像形成装置において
は、退避位置へ戻るカム３８が係合する係合溝４０が像
担持体側に形成され、これによりカム３８を確実に退避
位置に戻すことができる。この構成も、後述する各実施
形態例に対しても適用できるものである。As described above, in the image forming apparatus of the present embodiment, the engaging groove 40 is formed on the image carrier side for engaging the cam 38 returning to the retracted position, thereby ensuring that the cam 38 is returned to the retracted position. Can be. This configuration is also applicable to each embodiment described later.

【００６２】ところで、本例の画像形成装置において
は、感光体表面の転写残トナーをクリーニング部材２４
によって除去し終えた後、感光体５を第２の方向に回転
させ、このときの感光体５の回転を利用して転写ローラ
１１を感光体表面から離間させているのであるが、この
ように感光体５が第２の方向へ回転するとき、クリーニ
ング部材２４の先端エッジ部に溜っていた紙粉やトナー
が感光体表面に付着したまま、その感光体５と共に転写
ローラ１１に近づく。その際、図５に示すように転写ロ
ーラ１１が感光体５から離間し終える前に、感光体表面
に付着したトナーや紙粉が転写ローラ１１へ至ったとす
ると、そのトナーや紙粉が転写ローラ１１の表面に付着
する。このように転写ローラが汚れると、次の画像形成
動作時に、転写ローラ１１に付着したトナーや紙粉が転
写紙Ｐの裏面に付着し、その転写紙を汚してしまうおそ
れがある。In the image forming apparatus of this embodiment, the transfer residual toner on the surface of the photoreceptor is cleaned by the cleaning member 24.
After the removal, the photoconductor 5 is rotated in the second direction, and the rotation of the photoconductor 5 at this time is used to separate the transfer roller 11 from the surface of the photoconductor. When the photoreceptor 5 rotates in the second direction, the paper dust and toner accumulated at the leading edge of the cleaning member 24 approach the transfer roller 11 together with the photoreceptor 5 while adhering to the surface of the photoreceptor. At this time, assuming that toner or paper dust adhering to the surface of the photoconductor reaches the transfer roller 11 before the transfer roller 11 is completely separated from the photoconductor 5, as shown in FIG. 11 adheres to the surface. If the transfer roller becomes dirty in this manner, there is a possibility that the toner or paper dust that has adhered to the transfer roller 11 will adhere to the back surface of the transfer paper P during the next image forming operation, and will stain the transfer paper.

【００６３】そこで、本例の画像形成装置においては、
感光体５が回転を停止した後、この感光体５が第２の方
向に回転を開始してから、転写ローラ１１が感光体５表
面から離間して感光体５が停止するまでに、感光体５が
回転する角度が、クリーニング部材２４が感光体５に接
する点と、転写ローラ１１が感光体５に接する点のなす
角度θ（図４）よりも小さく設定されている。すなわ
ち、像担持体が第２の方向に回転し始め、その回転に伴
って転写部材が像担持体表面から離間し、次いで像担持
体が回転を停止するまでに、像担持体表面上の一点がそ
の表面に沿って移動する距離が、転写部材が像担持体表
面に当接する当接点から、クリーニング部材が像担持体
表面に当接する当接点までの像担持体表面に沿う距離よ
りも短かく設定されているのである。この構成も、後述
する各実施形態胆にも適用できるものである。かかる構
成によれば、感光体５が第２の方向に回転し始め、次い
でこれが停止するまでに、クリーニング部材２４の先端
エッジ部に溜っていたトナーや紙粉が転写ローラ１１の
ところまで至ることはなく、よってそのトナーや紙粉に
よって転写ローラが汚される不具合を阻止できる。Therefore, in the image forming apparatus of this embodiment,
After the photoreceptor 5 stops rotating, the photoreceptor 5 starts rotating in the second direction until the transfer roller 11 separates from the surface of the photoreceptor 5 and stops. The rotation angle of the rotating member 5 is set smaller than the angle θ (FIG. 4) formed by the point at which the cleaning member 24 contacts the photosensitive member 5 and the point at which the transfer roller 11 contacts the photosensitive member 5. That is, the image carrier starts to rotate in the second direction, the transfer member separates from the surface of the image carrier with the rotation, and then a point on the surface of the image carrier until the image carrier stops rotating. Is shorter than the distance along the surface of the image carrier from the contact point where the transfer member contacts the image carrier surface to the contact point where the cleaning member contacts the image carrier surface. It is set. This configuration can also be applied to each embodiment described below. According to this configuration, the toner and paper dust accumulated at the leading edge of the cleaning member 24 reach the transfer roller 11 before the photoconductor 5 starts rotating in the second direction and then stops. Therefore, it is possible to prevent the transfer roller from being stained by the toner or paper dust.

【００６４】以上説明した例では、転写部材が転写ロー
ラ１１として構成されているが、転写部材が、像担持体
表面に接離可能であって、画像形成動作時に、転写材を
介し、又は直に像担持体表面に当接する転写ブラシ、転
写ブレード、転写ベルト或いは転写ドラムなどから構成
される画像形成装置にも本発明を適用できる。In the above-described example, the transfer member is configured as the transfer roller 11, but the transfer member can be brought into contact with and separated from the surface of the image carrier, and can be directly or interposed between the transfer members during the image forming operation. The present invention is also applicable to an image forming apparatus including a transfer brush, a transfer blade, a transfer belt, a transfer drum, and the like, which are in contact with the surface of the image carrier.

【００６５】図６及び図７は、転写部材が転写ベルト４
１より成る画像形成装置の一例を示す概略図である。こ
こに示した転写ベルト４１は、複数の、図の例では２個
の転写部材プーリ４２，４３に巻き掛けられている。こ
れらのプーリ４２，４３の中心軸４５，４６は、共通の
フレーム４４に回転自在に支持され、ドラム状の感光体
５より成る像担持体から離れた側のプーリ４３の中心軸
４６を中心として、フレーム４４が揺動可能に支持され
ている。またフレーム４４の自由端側は、圧縮スプリン
グ４７より成る加圧部材によって付勢され、これによっ
て、画像形成動作時には、図６に示したように感光体５
に対向したプーリ４２が転写ベルト４１を介して感光体
表面に圧接する。FIGS. 6 and 7 show that the transfer member is the transfer belt 4.
FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus including an image forming apparatus; The transfer belt 41 shown here is wound around a plurality of, in the illustrated example, two transfer member pulleys 42 and 43. The center axes 45, 46 of these pulleys 42, 43 are rotatably supported by a common frame 44, and are centered on the center axis 46 of the pulley 43, which is away from the image carrier composed of the drum-shaped photoreceptor 5. , The frame 44 is swingably supported. Further, the free end side of the frame 44 is urged by a pressing member formed of a compression spring 47, so that during the image forming operation, as shown in FIG.
The pulley 42 opposing the surface contacts the photoreceptor surface via the transfer belt 41.

【００６６】図５及び図６に示した感光体５にも、図３
に示したギア３６に相当するギア（図示せず）が一体に
付設され、同じく感光体５に対向したプーリ（以下これ
を対向プーリという）４２にも、図３に示したギア３７
に相当するギア（同じく図示せず）が一体に付設されて
いて、両ギアは互いに噛み合い、感光体５側の回転を対
向プーリ４２に伝える伝動手段を構成している。従っ
て、画像形成動作時に感光体５が図６に実線矢印で示し
た第１の方向に回転駆動されると、この回転が対向プー
リ４２に伝えられ、これによって転写ベルト４１が同じ
く図６に実線矢印で示した第１方向に回転駆動される。
また対向プーリ４２には、図３に示したカムと同様なカ
ム３８が、先に説明したワンウェイクラッチと同様に構
成されたワンウェイクラッチを介して支持されている。The photosensitive member 5 shown in FIG. 5 and FIG.
A gear (not shown) corresponding to the gear 36 shown in FIG. 3 is integrally provided, and a pulley 42 (hereinafter referred to as an opposed pulley) also facing the photoreceptor 5 is provided with a gear 37 shown in FIG.
(Also not shown) are integrally provided, and the two gears mesh with each other to constitute transmission means for transmitting the rotation of the photoconductor 5 to the opposing pulley 42. Accordingly, when the photoconductor 5 is driven to rotate in the first direction shown by the solid line arrow in FIG. 6 during the image forming operation, this rotation is transmitted to the opposing pulley 42, whereby the transfer belt 41 is similarly moved to the solid line in FIG. It is driven to rotate in the first direction indicated by the arrow.
A cam 38 similar to the cam shown in FIG. 3 is supported on the opposing pulley 42 via a one-way clutch configured similarly to the one-way clutch described above.

【００６７】画像形成動作時には、感光体５は第１の方
向に回転し、このとき、図２を参照して先に説明した例
と全く同様にして、感光体表面にトナー像が形成され
る。その際、転写ベルト４１は、感光体表面に当接しな
がら第１方向に回転する。一方、図示していない給紙装
置から給送された転写紙Ｐより成る転写材は、所定のタ
イミングで感光体５と転写ベルト４１との間に送り込ま
れる。このとき、転写ベルト４１の裏面に当接したバイ
アスローラ４８に印加された転写電圧の作用によって、
感光体上のトナー像が転写紙Ｐ上に転写される。During the image forming operation, the photosensitive member 5 rotates in the first direction. At this time, a toner image is formed on the surface of the photosensitive member in exactly the same manner as in the example described above with reference to FIG. . At that time, the transfer belt 41 rotates in the first direction while abutting on the photoconductor surface. On the other hand, a transfer material composed of transfer paper P fed from a paper feeding device (not shown) is fed between the photoconductor 5 and the transfer belt 41 at a predetermined timing. At this time, the transfer voltage applied to the bias roller 48 in contact with the back surface of the transfer belt 41 causes
The toner image on the photoconductor is transferred onto the transfer paper P.

【００６８】感光体５から離れた転写紙は引き続き転写
ベルト４１に担持されて図示していない定着装置へ搬送
され、ここで転写されたトナー像が転写紙Ｐ上に定着さ
れる。感光体５に付着する転写残トナーはクリーニング
部材２４によって除去される。このとき、対向プーリ４
２の回転がカム３８に伝えられることはない。The transfer paper separated from the photoreceptor 5 is subsequently carried on a transfer belt 41 and conveyed to a fixing device (not shown), where the transferred toner image is fixed on the transfer paper P. The transfer residual toner adhered to the photoconductor 5 is removed by the cleaning member 24. At this time, the opposed pulley 4
The second rotation is not transmitted to the cam 38.

【００６９】ここで、感光体５上の転写残トナーの除去
を終了すると、感光体が図６に破線矢印で示した第２の
方向に所定量だけ回転駆動され、これによって対向プー
リ４２も破線矢印で示す方向に回転して転写ベルト４１
が破線矢印で示す第２方向に回転する。この対向プーリ
４２の回転はカム３８に伝えられ、当該カムが回転し
て、図７に示すように感光体５の端部材（図示せず）に
係合し、転写ベルト４１が感光体５から離間する。Here, when the removal of the transfer residual toner on the photosensitive member 5 is completed, the photosensitive member is driven to rotate by a predetermined amount in the second direction indicated by the broken line arrow in FIG. The transfer belt 41 rotates in the direction indicated by the arrow
Rotate in the second direction indicated by the dashed arrow. The rotation of the opposing pulley 42 is transmitted to a cam 38, which rotates and engages with an end member (not shown) of the photoconductor 5 as shown in FIG. Separate.

【００７０】感光体５が第１の方向への回転を再開する
と、カム３８は感光体側から受ける力によって、図６に
示した退避位置に戻り、転写ベルト４１が感光体表面に
当接し、画像形成動作が実行される。When the photosensitive member 5 resumes rotation in the first direction, the cam 38 returns to the retracted position shown in FIG. 6 by the force received from the photosensitive member side, and the transfer belt 41 comes into contact with the photosensitive member surface, and A forming operation is performed.

【００７１】上述のように、図６及び図７に示した画像
形成装置においては、転写部材が、複数の転写部材用プ
ーリ４２，４３に巻き掛けられ、かつ感光体５より成る
像担持体表面に接離可能であり、像担持体の回転に連動
して第１方向又は第２方向に回転し、像担持体表面に当
接しながら第１方向に回転するとき、像担持体表面のト
ナー像が転写される転写紙Ｐより成る転写材を担持して
搬送する転写ベルト４１より成り、転写部材接離手段
が、複数の転写部材用プーリ４２，４３のうち、転写ベ
ルト４１を介して像担持体に対向する対向プーリ４２に
付設されたカム３８と、該カム３８と対向プーリ４２と
の間に介設されたクラッチとを具備し、該クラッチは、
像担持体が第１の方向に回転し、これに連動して前記対
向プーリと転写ベルトが第１方向に回転するとき、カム
３８が退避位置に保持されるように対向プーリ４２の回
転をカム３８に伝えず、像担持体が第２の方向に回転
し、これに連動して対向プーリ４２と転写ベルト４１が
第２方向に回転するとき、カム３８が像担持体側に係合
して転写ベルト４１が像担持体表面から離間するよう
に、対向プーリ４２の回転をカム３８に伝えるワンウェ
イクラッチとして構成されている。As described above, in the image forming apparatus shown in FIGS. 6 and 7, the transfer member is wound around the plurality of transfer member pulleys 42 and 43, and the surface of the image carrier made of the photosensitive member 5 is formed. When the image carrier rotates in the first direction or the second direction in conjunction with the rotation of the image carrier and rotates in the first direction while contacting the surface of the image carrier, the toner image on the surface of the image carrier is And a transfer belt 41 that carries and conveys a transfer material made of transfer paper P to which the image is transferred. The transfer member contacting / separating means is an image bearing member via the transfer belt 41 among the plurality of transfer member pulleys 42 and 43. The cam includes a cam 38 attached to an opposing pulley 42 facing the body, and a clutch interposed between the cam 38 and the opposing pulley 42.
When the image carrier rotates in the first direction and the opposing pulley and the transfer belt rotate in the first direction in conjunction therewith, the rotation of the opposing pulley 42 is controlled so that the cam 38 is held at the retracted position. 38, the image carrier rotates in the second direction, and in conjunction therewith, when the opposing pulley 42 and the transfer belt 41 rotate in the second direction, the cam 38 engages with the image carrier and transfers the image. It is configured as a one-way clutch that transmits the rotation of the opposing pulley 42 to the cam 38 so that the belt 41 is separated from the surface of the image carrier.

【００７２】他の構成は、図１乃至図５に示したところ
と変りはなく、像担持体側の回転を前記対向プーリ４２
に伝えるギアより成る伝動手段を有し、転写ベルト４１
が像担持体表面から離間したときも、像担持体側から対
向プーリ４２に回転が伝えられるように、前記伝動手段
が構成されている点も変りはない。この構成により、カ
ムを確実に感光体５の側に係合させ、かつ感光体５の第
１の方向への回転時に対向プーリ４２、ひいては転写ベ
ルト４１を第１方向に確実に回転させることができる。The other structure is the same as that shown in FIGS. 1 to 5, and the rotation on the image carrier side is
Transfer means comprising a gear for transmitting to the transfer belt 41
There is no change in the point that the transmission means is configured so that the rotation is transmitted from the image carrier side to the opposing pulley 42 even when is separated from the image carrier surface. With this configuration, the cam can be reliably engaged with the photoconductor 5 side, and the opposing pulley 42, and thus the transfer belt 41, can be surely rotated in the first direction when the photoconductor 5 rotates in the first direction. it can.

【００７３】図８は、転写部材が転写ドラム４９として
構成された実施形態例を示す。画像形成動作時に、転写
ドラム４９に転写紙より成る転写材が巻き付けられて保
持される。当該転写ドラム４９とドラム状の感光体５よ
り成る像担持体には、図３を参照して説明したギア３
６，３７と同様のギア（図８には図示せず）が固定さ
れ、これが互いに噛み合って感光体５の回転を転写ドラ
ム４９に伝える伝動手段を構成している。転写ドラム４
９は感光体５に対して接離可能に支持されている。FIG. 8 shows an embodiment in which the transfer member is configured as a transfer drum 49. During the image forming operation, a transfer material made of transfer paper is wound around and held by the transfer drum 49. The image bearing member including the transfer drum 49 and the drum-shaped photoconductor 5 has the gear 3 described with reference to FIG.
Gears (not shown in FIG. 8) similar to the gears 6 and 37 are fixed, and mesh with each other to constitute transmission means for transmitting the rotation of the photoconductor 5 to the transfer drum 49. Transfer drum 4
9 is supported so as to be able to contact and separate from the photoconductor 5.

【００７４】画像形成動作時に感光体５は実線矢印で示
した第１の方向に回転し、これに連動して転写ドラム４
９も、感光体５の表面に当接しながら実線矢印で示した
第１方向に回転駆動される。これによって転写ドラム４
９の表面に保持された転写紙が搬送される。感光体５の
表面には、先に説明した実施形態例と同様にして、トナ
ー像が形成され、このトナー像が、転写ドラム４９の内
側に設けられた図示していないコロナ放電器又はローラ
からの電圧印加により、転写紙上に転写される。この例
では、感光体５上に順次異なった色のトナー像を形成
し、これを順次転写紙上に転写することもできる。トナ
ー像転写後に、転写紙は転写ドラム４９から分離されて
定着装置へ搬送される。During the image forming operation, the photosensitive member 5 rotates in a first direction indicated by a solid arrow, and in conjunction therewith, the transfer drum 4 rotates.
9 is also driven to rotate in the first direction indicated by the solid arrow while being in contact with the surface of the photoconductor 5. Thereby, the transfer drum 4
The transfer paper held on the surface of No. 9 is conveyed. A toner image is formed on the surface of the photoreceptor 5 in the same manner as in the embodiment described above, and the toner image is formed by a corona discharger or roller (not shown) provided inside the transfer drum 49. Is transferred onto the transfer paper by applying the voltage of. In this example, toner images of different colors can be sequentially formed on the photoreceptor 5 and sequentially transferred onto transfer paper. After the transfer of the toner image, the transfer paper is separated from the transfer drum 49 and transported to the fixing device.

【００７５】転写ドラム４９には、先に説明したカムと
同様なカム（図示せず）が同じく先に説明したクラッチ
と同様なワンウェイクラッチを介して支持されている。A cam (not shown) similar to the above-described cam is supported on the transfer drum 49 via a one-way clutch similar to the above-described clutch.

【００７６】各トナー像の転写後に感光体表面に付着す
る転写残トナーは、図８には示していないクリーニング
部材によって除去される。その感光体清掃動作を終えた
後、感光体５は破線矢印で示す第２の方向に所定角度だ
け回転する。これによって、転写ドラム４９が破線で示
した第２方向に回転し、この回転がカムに伝えられ、そ
れまで退避位置を占めていたカムが回転して感光体５の
側に係合し、転写ドラム４９が感光体５から離間する。The transfer residual toner adhering to the surface of the photosensitive member after the transfer of each toner image is removed by a cleaning member not shown in FIG. After the photoconductor cleaning operation is completed, the photoconductor 5 rotates by a predetermined angle in the second direction indicated by the dashed arrow. As a result, the transfer drum 49 rotates in the second direction shown by the broken line, and this rotation is transmitted to the cam, and the cam which has occupied the retracted position until then rotates and engages with the photoreceptor 5 to transfer. The drum 49 is separated from the photoconductor 5.

【００７７】感光体５が第１の方向への回転を開始する
と、カムは退避位置に戻り、転写ドラム４９が感光体５
に当接する。When the photosensitive member 5 starts rotating in the first direction, the cam returns to the retracted position, and the transfer drum 49 moves to the photosensitive member 5.
Abut.

【００７８】上述のように、図８に示した画像形成装置
においては、転写部材が、感光体５より成る像担持体表
面に接離可能であり、かつ像担持体の回転に連動して第
１方向又は第２方向に回転し、像担持体表面に当接しな
がら第１方向に回転するとき、像担持体表面のトナー像
が転写される転写紙より成る転写材を表面に巻き付けて
搬送する転写ドラム４９より成り、転写部材接離手段
が、転写ドラム４９に付設されたカムと、該カムと転写
ドラム４９との間に介設されたクラッチとを具備し、該
クラッチは、像担持体が第１の方向に回転し、これに連
動して転写ドラム４９が第１方向に回転するとき、カム
が退避位置に保持されるように転写ドラム４９の回転を
カムに伝えず、像担持体が第２の方向に回転し、これに
連動して転写ドラム４９が第２方向に回転するとき、カ
ムが像担持体側に係合して転写ドラム４９が像担持体表
面から離間するように、転写ドラムの回転をカムに伝え
るワンウェイクラッチとして構成されている。他の構成
は、図１乃至図５に示したところと変りはなく、像担持
体側の回転を前記転写ドラムに伝える伝動手段を有し、
転写ドラムが像担持体表面から離間したときも、像担持
体側から転写ドラム４９に回転が伝えられるように、伝
動手段が構成されている点も変りはない。As described above, in the image forming apparatus shown in FIG. 8, the transfer member can be brought into contact with and separated from the surface of the image bearing member composed of the photosensitive member 5, and the transfer member can be moved in conjunction with the rotation of the image bearing member. When rotating in one direction or the second direction and rotating in the first direction while abutting on the surface of the image carrier, a transfer material made of a transfer paper on which the toner image on the surface of the image carrier is transferred is wound around the surface and conveyed. The transfer member contacting / separating means includes a transfer drum 49, and a cam provided on the transfer drum 49, and a clutch interposed between the cam and the transfer drum 49. Rotates in the first direction, and when the transfer drum 49 rotates in the first direction in conjunction therewith, the rotation of the transfer drum 49 is not transmitted to the cam so that the cam is held at the retracted position. Rotates in the second direction, and in conjunction with this, the transfer drum When 9 is rotated in the second direction, the cam is configured to transfer drum 49 engages the image carrier-side is separated from the image bearing member surface, the rotation of the transfer drum as a one-way clutch for transmitting the cam. The other configuration is the same as that shown in FIGS. 1 to 5 and has a transmission unit for transmitting the rotation of the image carrier to the transfer drum,
Even when the transfer drum is separated from the surface of the image carrier, the transmission means is configured so that the rotation is transmitted to the transfer drum 49 from the image carrier side.

【００７９】以上説明した実施形態例では、像担持体が
トナー像を担持する像担持ドラムにより構成されている
が、図９に示すように、像担持体が複数の像担持体用プ
ーリ５１，５２，５３に巻き掛けられて、前述の第１又
は第２の方向に回転する像担持ベルト５０より成るとき
も本発明を適用できる。この場合には、複数の像担持体
のプーリ５１，５２，５３のうち、１つのプーリ５１
が、像担持ベルト５０を介して例えば転写ローラ１１よ
り成る転写部材に対向し、この転写ローラ１１のローラ
軸に図示していないワンウェイクラッチを介してカム
（図示せず）が支持される。この場合も、実線矢印で示
した第１の方向へ回転する像担持ベルト５０上に前述の
実施形態例と同じくトナー像が形成され、プーリ５１に
固定されたギアと、このギアに噛み合い、かつ転写ロー
ラ１１に固定されたギアとによって、像担持ベルト５０
の回転が転写ローラ１１に伝えられ、両者の間を搬送さ
れる転写紙Ｐ上に、像担持ベルト上に形成されたトナー
像が形成される。その像担持ベルト上に付着した転写残
トナーが図示していないクリーニング部材によって除去
され終ると、像担持ベルト５０が破線矢印で示した第２
の方向に回転駆動され、これによって転写ローラ１１も
破線矢印で示した第２方向に回転し、このときその回転
がワンウェイクラッチを介してカムに伝えられ、それま
で退避位置を占めていたカムが回動してプーリ５１に係
合し、転写ローラ１１が像担持ベルト５０から離間す
る。像担持ベルト５０の第１の方向への回転に伴ってカ
ムはプーリ５１から受ける力によって退避位置に戻り、
転写ローラ１１が像担持ベルト５０に当接する。このよ
うに、この例では、像担持体が複数の像担持体用プーリ
に巻き掛けられて第１又は第２の方向に回転する像担持
ベルトより成り、転写部材に付設されたカムが、複数の
像担持体用プーリ５１，５２，５３のうち、像担持ベル
ト５０を介して転写部材に対向した像担持体用プーリ５
１に係合して転写部材を像担持ベルト表面から離間させ
る。他の構成と作用は、先に説明した各実施形態例と変
りはない。In the embodiment described above, the image carrier is constituted by an image carrier drum for carrying a toner image. However, as shown in FIG. 9, the image carrier comprises a plurality of image carrier pulleys 51, The present invention can also be applied to a case where the image bearing belt 50 is wound around 52 and 53 and rotates in the above-described first or second direction. In this case, one of the pulleys 51, 52, 53 of the plurality of image carriers is
Is opposed to a transfer member including, for example, the transfer roller 11 via the image carrying belt 50, and a cam (not shown) is supported on a roller shaft of the transfer roller 11 via a one-way clutch (not shown). Also in this case, a toner image is formed on the image bearing belt 50 that rotates in the first direction indicated by the solid arrow similarly to the above-described embodiment, and meshes with a gear fixed to the pulley 51 and this gear, and The image holding belt 50 is moved by the gear fixed to the transfer roller 11.
Is transmitted to the transfer roller 11, and the toner image formed on the image carrying belt is formed on the transfer paper P conveyed between the two. When the transfer residual toner adhered to the image carrying belt is completely removed by a cleaning member (not shown), the image carrying belt 50 is moved to the second position indicated by the broken arrow.
, Whereby the transfer roller 11 also rotates in the second direction indicated by the dashed arrow. At this time, the rotation is transmitted to the cam via the one-way clutch. The transfer roller 11 is rotated and engaged with the pulley 51, and the transfer roller 11 is separated from the image carrying belt 50. With the rotation of the image carrying belt 50 in the first direction, the cam returns to the retracted position by the force received from the pulley 51,
The transfer roller 11 comes into contact with the image carrying belt 50. As described above, in this example, the image carrier is wound around a plurality of image carrier pulleys, and is formed of an image carrier belt that rotates in the first or second direction, and a plurality of cams attached to the transfer member are provided. Among the image carrier pulleys 51, 52, 53, the image carrier pulley 5 facing the transfer member via the image carrier belt 50.
1 to separate the transfer member from the surface of the image bearing belt. Other configurations and operations are the same as those of the embodiments described above.

【００８０】以上説明した各実施形態例では、像担持体
が、静電潜像を形成され、その静電潜像がトナー像とし
て可視像化される潜像担持体として構成されている。こ
れに対し、図１０に示した例では、像担持体が、潜像担
持体からトナーを転写される中間転写体として構成され
ており、かかる画像形成装置にも本発明を適用できる。In each of the embodiments described above, the image carrier is formed as a latent image carrier on which an electrostatic latent image is formed and the electrostatic latent image is visualized as a toner image. On the other hand, in the example shown in FIG. 10, the image carrier is configured as an intermediate transfer member to which the toner is transferred from the latent image carrier, and the present invention can be applied to such an image forming apparatus.

【００８１】図１０に示した例では、ドラム状の感光体
５より成る潜像担持体の表面に順次色の異なるトナー像
が形成され、この各トナー像が複数のプーリに巻き掛け
られたベルトより成る中間転写体５４に順次一次転写さ
れ、その重ね合せトナー像が転写ローラ１１より成る転
写部材によって、転写紙Ｐ上に二次転写される。かかる
中間転写体５４と転写ローラ１１として、前述した各構
成を採用して画像形成装置を構成することができる。In the example shown in FIG. 10, toner images of different colors are sequentially formed on the surface of a latent image carrier composed of a drum-shaped photoreceptor 5, and these toner images are wound around a plurality of pulleys. The toner image is sequentially primary-transferred onto the intermediate transfer member 54, and the superimposed toner image is secondarily transferred onto the transfer paper P by the transfer member including the transfer roller 11. As the intermediate transfer member 54 and the transfer roller 11, the image forming apparatus can be configured by adopting the respective configurations described above.

【００８２】以上説明した例では１つのカム３８を用い
たが、複数のカムを用いてもよい。例えば図３に示した
ローラ軸２８の他端側にも、ワンウェイクラッチを介し
てもう１つのカムを設けることもできる。In the example described above, one cam 38 is used, but a plurality of cams may be used. For example, another cam may be provided on the other end side of the roller shaft 28 shown in FIG. 3 via a one-way clutch.

【００８３】また像担持体の表面をクリーニング部材に
よって清掃し終えた後、像担持体を第２の方向に回転さ
せて転写部材を像担持体表面から離間させたが、他のタ
イミングで像担持体を第２の方向に回転させ、転写部材
を像担持体から離すように構成することもできる。After the surface of the image carrier has been cleaned by the cleaning member, the image carrier is rotated in the second direction to separate the transfer member from the surface of the image carrier. The transfer member may be separated from the image carrier by rotating the body in the second direction.

【００８４】本発明は複写機以外の画像形成装置にも広
く適用できるものである。The present invention can be widely applied to image forming apparatuses other than copying machines.

【００８５】[0085]

【発明の効果】請求項１乃至２１に記載の構成によれ
ば、転写部材が常に像担持体に当接することを阻止で
き、像担持体表面に転写部材の跡が残ったり、転写部材
に永久歪みができることを防止できる。しかも、像担持
体が第２の方向に回転するとき、その回転動作を利用し
て転写部材を像担持体から離間させ、また像担持体が第
１の方向に回転するとき、その回転を利用して転写部材
を像担持体表面に当接させるので、転写部材を像担持体
表面に対して接離させるための専用の駆動装置を必要と
せず、画像形成装置のコストを低減できる。According to the first to twenty-first aspects of the present invention, the transfer member can be prevented from constantly abutting on the image carrier, leaving traces of the transfer member on the surface of the image carrier, or permanent transfer to the transfer member. Distortion can be prevented. Moreover, when the image carrier rotates in the second direction, the transfer member is separated from the image carrier by using the rotation operation, and when the image carrier rotates in the first direction, the rotation is used. Then, since the transfer member is brought into contact with the surface of the image carrier, a dedicated driving device for moving the transfer member toward and away from the surface of the image carrier is not required, and the cost of the image forming apparatus can be reduced.

【００８６】また請求項７に記載の画像形成装置によれ
ば、転写ローラを像担持体表面に均一な圧力で当接させ
ることができる。According to the image forming apparatus of the present invention, the transfer roller can be brought into contact with the surface of the image carrier with a uniform pressure.

【００８７】さらに、請求項８、１０及び１２に記載の
構成によれば、転写部材をより確実に像担持体表面から
離間させ、かつ像担持体が第１の方向に回転し始めたと
き、より確実に転写部材を像担持体表面に当接させるこ
とができる。Further, according to the configuration of the eighth, tenth and twelfth aspects, when the transfer member is more reliably separated from the surface of the image carrier and the image carrier starts to rotate in the first direction, The transfer member can be more reliably brought into contact with the surface of the image carrier.

【００８８】請求項１４に記載の構成によれば、像担持
体が第１の方向に回転し始めたとき、カムをより確実に
退避位置に戻すことができる。According to the structure described in claim 14, when the image carrier starts to rotate in the first direction, the cam can be more reliably returned to the retracted position.

【００８９】請求項１７及び１８に記載の構成によれ
ば、クリーニング部材に溜ったトナーや紙粉を除去する
ために像担持体を第２の方向に回転する時間を利用し
て、転写部材を像担持体表面から離間させることができ
る。According to the constructions of the seventeenth and eighteenth aspects, the time required to rotate the image carrier in the second direction in order to remove the toner and paper dust accumulated on the cleaning member is utilized. It can be separated from the image carrier surface.

【００９０】請求項１９に記載の構成によれば、クリー
ニング部材に溜ったトナーや紙粉が転写部材に付着する
不具合を防止できる。According to the configuration of the nineteenth aspect, it is possible to prevent a problem that toner and paper dust accumulated in the cleaning member adhere to the transfer member.

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

【図１】画像形成装置の全体構成を示す概略断面図であ
る。FIG. 1 is a schematic sectional view showing the overall configuration of an image forming apparatus.

【図２】図１の一部を拡大して示す断面図である。FIG. 2 is an enlarged sectional view showing a part of FIG. 1;

【図３】感光体、転写ローラ及びカムの相対位置を説明
する斜視図である。FIG. 3 is a perspective view illustrating relative positions of a photoconductor, a transfer roller, and a cam.

【図４】感光体が第１の方向に回転しているときのカム
の位置を示す説明図である。FIG. 4 is an explanatory diagram showing a position of a cam when the photoconductor is rotating in a first direction.

【図５】カムが感光体側に係合して転写ローラが感光体
から離れたときの様子を示す説明図である。FIG. 5 is an explanatory diagram illustrating a state in which a cam is engaged with a photoconductor and a transfer roller is separated from the photoconductor;

【図６】転写部材が転写ベルトより成る画像形成装置を
示す説明図である。FIG. 6 is an explanatory diagram illustrating an image forming apparatus in which a transfer member includes a transfer belt.

【図７】図６に示したカムが感光体側に係合して転写ベ
ルトが感光体表面から離間した様子を示す説明図であ
る。FIG. 7 is an explanatory view showing a state in which the cam shown in FIG. 6 is engaged with the photoconductor and the transfer belt is separated from the surface of the photoconductor.

【図８】転写部材が転写ドラムより成る画像形成装置の
概略説明図である。FIG. 8 is a schematic explanatory view of an image forming apparatus in which a transfer member includes a transfer drum.

【図９】感光体がベルトにより構成された例を示す概略
説明図である。FIG. 9 is a schematic explanatory view showing an example in which a photoconductor is constituted by a belt.

【図１０】感光体上のトナー像を中間転写体に転写する
形式の画像形成装置の概略を示す説明図である。FIG. 10 is an explanatory view schematically showing an image forming apparatus of a type in which a toner image on a photosensitive member is transferred to an intermediate transfer member.

【符号の説明】[Explanation of symbols]

１１ 転写ローラ ２２ 端部材 ２４ クリーニング部材 ２８ ローラ軸 ２９ ローラ本体 ３８ カム ３９ ワンウェイクラッチ ４０ 係合溝 ４１ 転写ベルト ４２ プーリ ４３ プーリ ４９ 転写ドラム ５０ 像担持ドラム ５１ プーリ ５２ プーリ ５３ プーリ ５４ 中間転写体 REFERENCE SIGNS LIST 11 transfer roller 22 end member 24 cleaning member 28 roller shaft 29 roller body 38 cam 39 one-way clutch 40 engagement groove 41 transfer belt 42 pulley 43 pulley 49 transfer drum 50 image carrying drum 51 pulley 52 pulley 52 pulley 53 pulley 54 intermediate transfer body

Claims (21)

【特許請求の範囲】[Claims] 【請求項１】 第１の方向に回転駆動されつつ表面にト
ナー像を形成される像担持体と、転写材を介して像担持
体表面に当接しながら像担持体表面に形成されたトナー
像を転写材に転写するための転写部材と、トナー像転写
後の像担持体表面に付着する転写残トナーを像担持体表
面から除去して当該像担持体表面を清掃するクリーニン
グ部材とを具備し、前記像担持体は、前記第１の方向と
は逆の第２の方向にも回転可能である画像形成装置にお
いて、 前記転写部材を像担持体表面に対して接離可能に支持す
ると共に、前記像担持体が第２の方向に回転するとき、
その回転によって駆動され、像担持体表面に当接してい
た転写部材を像担持体表面から離間させ、かつ像担持体
が第１の方向に回転したとき、その回転によって駆動さ
れ、像担持体表面から離間していた転写部材を像担持体
表面に当接させる転写部材接離手段を設けたことを特徴
とする画像形成装置。An image carrier having a toner image formed on the surface thereof while being driven to rotate in a first direction, and a toner image formed on the image carrier surface while being in contact with the image carrier surface via a transfer material A transfer member for transferring the toner image onto the transfer material, and a cleaning member for removing the transfer residual toner adhered to the surface of the image carrier after transferring the toner image from the image carrier surface and cleaning the image carrier surface. An image forming apparatus wherein the image carrier is rotatable also in a second direction opposite to the first direction, while supporting the transfer member so as to be able to approach and separate from a surface of the image carrier; When the image carrier rotates in the second direction,
When the image carrier rotates in a first direction, the transfer member driven by the rotation of the image carrier separates from the surface of the image carrier, and is driven by the rotation. An image forming apparatus provided with a transfer member contacting / separating means for contacting the transfer member separated from the image carrier with the surface of the image carrier. 【請求項２】 前記転写部材接離手段が、転写部材側に
設けられていて、像担持体が第２の方向に回転したと
き、その回転によって駆動され退避位置から作動して像
担持体側に係合することにより、転写部材を像担持体表
面から離間させ、像担持体が第１の方向に回転したと
き、その回転によって駆動されて退避位置に戻り、転写
部材を像担持体表面に当接させるカムを有している請求
項１に記載の画像形成装置。2. The image forming apparatus according to claim 1, wherein the transfer member contacting / separating means is provided on the transfer member side, and when the image carrier rotates in a second direction, is driven by the rotation and operates from a retracted position to move to the image carrier side. The engagement causes the transfer member to be separated from the surface of the image carrier, and when the image carrier rotates in the first direction, the image carrier is driven by the rotation to return to the retracted position, and the transfer member contacts the surface of the image carrier. The image forming apparatus according to claim 1, further comprising a cam that is in contact with the image forming apparatus. 【請求項３】 前記転写部材接離手段が、前記カムと転
写部材との間に介設され、像担持体が第１の方向に回転
するとき、その像担持体の回転をカムに伝えず、像担持
体が第２の方向に回転したとき、前記カムが像担持体側
に係合するように、像担持体の回転を前記カムに伝える
クラッチを有している請求項２に記載の画像形成装置。3. The transfer member contacting / separating means is interposed between the cam and the transfer member. When the image carrier rotates in a first direction, the rotation of the image carrier is not transmitted to the cam. The image according to claim 2, further comprising a clutch for transmitting rotation of the image carrier to the cam so that the cam engages with the image carrier when the image carrier rotates in the second direction. Forming equipment. 【請求項４】 転写部材が、伝動手段を介して、像担持
体に駆動連結され、像担持体の回転が転写部材に伝達さ
れて当該転写部材が回転駆動され、転写部材が像担持体
表面から離間したときも、像担持体から転写部材に回転
が伝えられるように、前記伝動手段を構成した請求項１
乃至３のいずれかに記載の画像形成装置。4. A transfer member is drivingly connected to an image carrier via a transmission means, and rotation of the image carrier is transmitted to the transfer member to rotate the transfer member. The transmission means is configured such that rotation is transmitted from the image carrier to the transfer member even when the transfer member is separated from the transfer member.
An image forming apparatus according to any one of claims 1 to 3. 【請求項５】 前記転写部材が、像担持体表面に接離可
能であり、かつ像担持体の回転に連動して第１方向又は
第２方向に回転する転写ローラより成り、前記転写部材
接離手段が、転写ローラに付設されたカムと、該カムと
転写ローラとの間に介設されたクラッチとを具備し、該
クラッチは、像担持体が第１の方向に回転し、これに連
動して転写ローラが像担持体表面に当接しながら第１方
向に回転するとき、前記カムが退避位置に保持されるよ
うに、転写ローラの回転を前記カムに伝えず、像担持体
が第２の方向に回転し、これに連動して転写ローラが第
２方向に回転するとき、前記カムが像担持体側に係合し
て転写ローラが像担持体表面から離間するように、転写
ローラの回転をカムに伝えるワンウェイクラッチとして
構成されている請求項１に記載の画像形成装置。5. The image forming apparatus according to claim 1, wherein the transfer member includes a transfer roller that is capable of coming into contact with and separating from the surface of the image carrier and that rotates in a first direction or a second direction in conjunction with rotation of the image carrier. The separating means includes a cam attached to the transfer roller, and a clutch interposed between the cam and the transfer roller, wherein the clutch rotates the image carrier in a first direction. When the transfer roller rotates in the first direction while being in contact with the surface of the image carrier, the rotation of the transfer roller is not transmitted to the cam so that the cam is held at the retracted position, and the image carrier is moved When the transfer roller rotates in the second direction in conjunction with this, when the transfer roller rotates in the second direction, the cam is engaged with the image carrier and the transfer roller is separated from the surface of the image carrier. Claims configured as a one-way clutch that transmits rotation to the cam Item 2. The image forming apparatus according to Item 1. 【請求項６】 前記転写ローラが、弾性体より成るロー
ラ本体と、該ローラ本体を固定支持する剛体より成るロ
ーラ軸とを有し、前記カムが前記ワンウェイクラッチを
介してローラ軸に支持されている請求項５に記載の画像
形成装置。6. The transfer roller has a roller body made of an elastic body, and a roller shaft made of a rigid body fixedly supporting the roller body, and the cam is supported by the roller shaft via the one-way clutch. The image forming apparatus according to claim 5. 【請求項７】 前記ローラ本体が像担持体表面に圧接す
るように、ローラ軸の軸方向各端部を加圧する加圧部材
を有する請求項６に記載の画像形成装置。7. The image forming apparatus according to claim 6, further comprising a pressing member that presses each end of the roller shaft in the axial direction such that the roller body comes into pressure contact with the surface of the image carrier. 【請求項８】 前記像担持体の回転を転写ローラに伝え
る伝動手段を有し、転写ローラが像担持体表面から離間
したときも、像担持体側から転写ローラに回転が伝えら
れるように、前記伝動手段を構成した請求項５乃至７の
いずれかに記載の画像形成装置。8. A transmission device for transmitting rotation of the image carrier to a transfer roller, wherein the rotation is transmitted from the image carrier to the transfer roller even when the transfer roller is separated from the surface of the image carrier. The image forming apparatus according to claim 5, wherein the image forming apparatus comprises a transmission unit. 【請求項９】 前記転写部材が、複数の転写部材用プー
リに巻き掛けられ、かつ像担持体表面に接離可能であ
り、像担持体の回転に連動して第１方向又は第２方向に
回転し、像担持体表面に当接しながら第１方向に回転す
るとき、像担持体表面のトナー像が転写される転写材を
担持して搬送する転写ベルトより成り、前記転写部材接
離手段が、前記複数の転写部材用プーリのうち、前記転
写ベルトを介して像担持体に対向する対向プーリに付設
されたカムと、該カムと前記対向プーリとの間に介設さ
れたクラッチとを具備し、該クラッチは、像担持体が第
１の方向に回転し、これに連動して前記対向プーリと転
写ベルトが第１方向に回転するとき、前記カムが退避位
置に保持されるように対向プーリの回転を前記カムに伝
えず、像担持体が第２の方向に回転し、これに連動して
対向プーリと転写ベルトが第２方向に回転するとき、前
記カムが像担持体側に係合して転写ベルトが像担持体表
面から離間するように、対向プーリの回転をカムに伝え
るワンウェイクラッチとして構成されている請求項１に
記載の画像形成装置。9. The transfer member is wound around a plurality of transfer member pulleys and is detachable from the surface of the image carrier, and is moved in the first direction or the second direction in conjunction with the rotation of the image carrier. A transfer belt that carries and conveys a transfer material onto which the toner image on the image carrier is transferred when rotating and rotating in the first direction while abutting on the surface of the image carrier; A cam attached to an opposing pulley facing the image carrier via the transfer belt among the plurality of transfer member pulleys; and a clutch interposed between the cam and the opposing pulley. When the image carrier rotates in the first direction and the opposing pulley and the transfer belt rotate in the first direction in conjunction therewith, the clutch is opposed so that the cam is held at the retracted position. The rotation of the pulley is not transmitted to the cam, and the image carrier When the opposing pulley and the transfer belt rotate in the second direction in conjunction with this, the cam engages with the image carrier and the transfer belt separates from the image carrier surface. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured as a one-way clutch that transmits rotation of a pulley to a cam. 【請求項１０】 前記像担持体側の回転を前記対向プー
リに伝える伝動手段を有し、転写ベルトが像担持体表面
から離間したときも、像担持体側から対向プーリに回転
が伝えられるように、前記伝動手段を構成した請求項９
に記載の画像形成装置。10. A transmission means for transmitting the rotation of the image carrier to the opposing pulley, wherein the rotation is transmitted from the image carrier to the opposing pulley even when the transfer belt is separated from the surface of the image carrier. 10. The power transmission device according to claim 9, wherein:
An image forming apparatus according to claim 1. 【請求項１１】 前記転写部材が、像担持体表面に接離
可能であり、かつ像担持体の回転に連動して第１方向又
は第２方向に回転し、像担持体表面に当接しながら第１
方向に回転するとき、像担持体表面のトナー像が転写さ
れる転写材を表面に巻き付けて搬送する転写ドラムより
成り、前記転写部材接離手段が、転写ドラムに付設され
たカムと、該カムと転写ドラムとの間に介設されたクラ
ッチとを具備し、該クラッチは、像担持体が第１の方向
に回転し、これに連動して転写ドラムが第１方向に回転
するとき、前記カムが退避位置に保持されるように転写
ドラムの回転を前記カムに伝えず、像担持体が第２の方
向に回転し、これに連動して転写ドラムが第２方向に回
転するとき、前記カムが像担持体側に係合して転写ドラ
ムが像担持体表面から離間するように、転写ドラムの回
転をカムに伝えるワンウェイクラッチとして構成されて
いる請求項１に記載の画像形成装置。11. The transfer member is detachable from the surface of the image carrier, and rotates in a first direction or a second direction in conjunction with rotation of the image carrier, and contacts the surface of the image carrier. First
A transfer material onto which a toner image on the surface of the image carrier is transferred when the toner image is transferred in the direction of rotation, and a transfer member contacting / separating means provided on the transfer drum; And a clutch interposed between the transfer drum and the transfer drum. The clutch is provided when the image bearing member rotates in a first direction and the transfer drum rotates in a first direction in conjunction with the rotation. When the rotation of the transfer drum is not transmitted to the cam so that the cam is held at the retracted position, the image carrier rotates in the second direction, and when the transfer drum rotates in the second direction in conjunction with the rotation, The image forming apparatus according to claim 1, wherein the image forming apparatus is configured as a one-way clutch that transmits rotation of the transfer drum to the cam so that the cam engages with the image carrier and the transfer drum separates from the surface of the image carrier. 【請求項１２】 前記像担持体側の回転を前記転写ドラ
ムに伝える伝動手段を有し、転写ドラムが像担持体表面
から離間したときも、像担持体側から転写ドラムに回転
が伝えられるように、前記伝動手段を構成した請求項１
１に記載の画像形成装置。12. A transfer device for transmitting rotation of the image carrier to the transfer drum, wherein the rotation is transmitted from the image carrier to the transfer drum even when the transfer drum is separated from the surface of the image carrier. 2. The power transmission device according to claim 1,
2. The image forming apparatus according to 1. 【請求項１３】 前記カムが像担持体側に係合して転写
部材が像担持体表面から離間した状態で、像担持体が第
１の方向に回転したとき、カムが、像担持体側から受け
る力によって退避位置に戻り、転写部材が像担持体表面
に当接する請求項５乃至１２のいずれかに記載の画像形
成装置。13. When the image carrier rotates in a first direction in a state where the cam is engaged with the image carrier and the transfer member is separated from the surface of the image carrier, the cam receives from the image carrier. The image forming apparatus according to claim 5, wherein the transfer member returns to the retracted position by force, and the transfer member contacts the surface of the image carrier. 【請求項１４】 退避位置へ戻るカムの縁部が係合する
係合溝が像担持体側に形成されている請求項２乃至１３
のいずれかに記載の画像形成装置。14. An image bearing member, wherein an engagement groove with which an edge of the cam returning to the retracted position is engaged is formed on the image carrier side.
The image forming apparatus according to any one of the above. 【請求項１５】 前記像担持体が像担持ドラムより成
り、該像担持ドラムが第２の方向に回転したとき、前記
カムが像担持ドラムの軸方向端部に固定された端部材に
係合して転写部材を像担持ドラム表面から離間させる請
求項２乃至１４のいずれかに記載の画像形成装置。15. The image bearing member comprises an image bearing drum, and when the image bearing drum rotates in a second direction, the cam engages with an end member fixed to an axial end of the image bearing drum. The image forming apparatus according to claim 2, wherein the transfer member is separated from the surface of the image bearing drum. 【請求項１６】 前記像担持体が複数の像担持体用プー
リに巻き掛けられて第１又は第２の方向に回転する像担
持ベルトより成り、前記カムが、前記複数の像担持体用
プーリのうち、像担持ベルトを介して転写部材に対向し
た像担持体用プーリに係合して転写部材を像担持ベルト
表面から離間させる請求項２乃至１４のいずれかに記載
の画像形成装置。16. The image carrier comprises an image carrier belt that is wound around a plurality of image carrier pulleys and rotates in a first or second direction, and wherein the cam includes the plurality of image carrier pulleys. 15. The image forming apparatus according to claim 2, wherein the transfer member is separated from the surface of the image carrying belt by engaging with a pulley for the image carrier facing the transfer member via the image carrying belt. 【請求項１７】 像担持体表面の転写残トナーをクリー
ニング部材によって除去し終えた後、像担持体が第２の
方向に回転する請求項１乃至１６のいずれかに記載の画
像形成装置。17. The image forming apparatus according to claim 1, wherein the image carrier rotates in the second direction after the transfer residual toner on the surface of the image carrier has been removed by the cleaning member. 【請求項１８】 前記クリーニング部材が、像担持体表
面に圧接してその表面に付着する転写残トナーを掻き取
るクリーニングブレードである請求項１７に記載の画像
形成装置。18. The image forming apparatus according to claim 17, wherein the cleaning member is a cleaning blade that presses against the surface of the image carrier to scrape off the untransferred toner attached to the surface. 【請求項１９】 前記像担持体が第２の方向に回転し始
め、その回転に伴って転写部材が像担持体表面から離間
し、次いで像担持体が回転を停止するまでに、像担持体
表面上の一点がその表面に沿って移動する距離が、転写
部材が像担持体表面に当接する当接点から、クリーニン
グ部材が像担持体表面に当接する当接点までの像担持体
表面に沿う距離よりも短かく設定されている請求項１７
又は１８に記載の画像形成装置。19. The image carrier according to claim 1, wherein said image carrier starts to rotate in a second direction, the transfer member separates from the surface of the image carrier with the rotation, and then the image carrier stops rotating. The distance along which the point on the surface moves along the surface is the distance along the surface of the image carrier from the contact point where the transfer member contacts the image carrier surface to the contact point where the cleaning member contacts the image carrier surface. 18. It is set shorter than
Or the image forming apparatus according to 18. 【請求項２０】 前記像担持体が、静電潜像を形成さ
れ、その静電潜像がトナー像として可視像化される潜像
担持体として構成された請求項１乃至１９のいずれかに
記載の画像形成装置。20. The latent image carrier according to claim 1, wherein the image carrier is formed with an electrostatic latent image, and the electrostatic latent image is visualized as a toner image. An image forming apparatus according to claim 1. 【請求項２１】 前記像担持体が、潜像担持体からトナ
ーを転写される中間転写体として構成された請求項１乃
至１９のいずれかに記載の画像形成装置。21. The image forming apparatus according to claim 1, wherein said image bearing member is configured as an intermediate transfer member to which toner is transferred from a latent image bearing member.
JP9189257A 1997-06-30 1997-06-30 Image forming device Pending JPH1124452A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP9189257A JPH1124452A (en) 1997-06-30 1997-06-30 Image forming device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9189257A JPH1124452A (en) 1997-06-30 1997-06-30 Image forming device

Publications (1)

Publication Number Publication Date
JPH1124452A true JPH1124452A (en) 1999-01-29

Family

ID=16238277

Family Applications (1)

Application Number Title Priority Date Filing Date
JP9189257A Pending JPH1124452A (en) 1997-06-30 1997-06-30 Image forming device

Country Status (1)

Country Link
JP (1) JPH1124452A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006189614A (en) * 2005-01-06 2006-07-20 Fuji Xerox Co Ltd Image forming apparatus
JP2007286455A (en) * 2006-04-19 2007-11-01 Canon Inc Process cartridge, electrophotographic image forming apparatus, and method of manufacturing and remanufacturing process cartridge
JP2007298545A (en) * 2006-04-27 2007-11-15 Canon Inc Image forming apparatus
JP2015090402A (en) * 2013-11-05 2015-05-11 キヤノン株式会社 Image forming apparatus

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
JP2007286455A (en) * 2006-04-19 2007-11-01 Canon Inc Process cartridge, electrophotographic image forming apparatus, and method of manufacturing and remanufacturing process cartridge
US7865115B2 (en) 2006-04-19 2011-01-04 Canon Kabushiki Kaisha Process cartridge, electrophotographic image forming apparatus, method of manufacturing a process cartridge, and method of remanufacturing a process cartridge
JP2007298545A (en) * 2006-04-27 2007-11-15 Canon Inc Image forming apparatus
US7702254B2 (en) 2006-04-27 2010-04-20 Canon Kabushiki Kaisha Image forming apparatus having mechanism for reducing pressing force between image bearing member and transferring member
JP2015090402A (en) * 2013-11-05 2015-05-11 キヤノン株式会社 Image forming apparatus

Similar Documents

Publication Publication Date Title
JP3542731B2 (en) Image forming device
JP4649893B2 (en) Image forming apparatus
US20140153957A1 (en) Cleaning device, intermediate transfer unit including the same, and image forming apparatus including the same
JP3596531B2 (en) Image forming device
JP2003057964A (en) Image forming device
JPH1124452A (en) Image forming device
JP2007093780A (en) Image forming apparatus and image forming method therefor
US11209742B1 (en) Image carrier unit and image forming apparatus including the same
JPH1010939A (en) Image forming device
JP2001356619A (en) Transfer device
JP2003131479A (en) Developing device, process cartridge and image forming device
JP3398317B2 (en) Color image forming equipment
JP2006119311A (en) Image forming apparatus
JP2022066812A (en) Photoreceptor unit
JP7237562B2 (en) photoreceptor unit
JP4078506B2 (en) Driving device and image forming apparatus using the same
JP3417518B2 (en) Image forming device
JP3696780B2 (en) Image forming apparatus and image carrier unit mounted thereon
JP2001343838A (en) Image forming device and cleaning device
JP4400155B2 (en) Image forming apparatus
JPH10282752A (en) Electrophotographic image forming device and process cartridge
JP2001272865A (en) Cleaning device, and image forming apparatus
JP2679304B2 (en) Image forming apparatus and process cartridge
JPH05188738A (en) Contact electrifier
JPH05323835A (en) Cleaning device for image forming device