JP2002244445A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device where the generation of an image failure such as a transfer disabling at edge parts can be surely prevented by easily recovering the initial high resistance even when a lowering in surface resistance is generated due to an abnormal discharge when transferring in a recording material carrier, paper non-passing part of an intermediate transfer body or a part where release oil is stuck. SOLUTION: In the device, a one side image forming function where image is formed on one side of recording material and a both sides image forming function where images are formed on both sides of the recording material are provided. In this case, the ratio between the surface polishing time or the polishing frequency of the recording material carrier 130 by a polishing means 70 when forming the both side images and the surface polishing time or the polishing frequency of the recording material carrier 130 by the polishing means 70 when forming the one side image are varied.

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、像担持体上のトナ
ー像を直接若しくは中間転写体を介して記録材に転写し
て、記録材に画像を形成する画像形成装置に関し、例え
ば記録材担持体或いは中間転写体として無端搬送ベルト
を使用した画像形成装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for transferring a toner image on an image carrier to a recording material directly or via an intermediate transfer member to form an image on the recording material. The present invention relates to an image forming apparatus using an endless conveyance belt as a member or an intermediate transfer member.

【０００２】[0002]

【従来の技術】従来、複数の画像形成部を備え、各画像
形成部でそれぞれ色の異なった複数色のトナー像を形成
し、そのトナー像を同一記録材上に順次重ね合わせて転
写して、記録材にカラー画像を形成する画像形成装置が
種々提案され、中でも高速記録に、ベルト状の記録材担
持体、即ち、記録材搬送ベルト（転写ベルト）を使用し
た多色電子写真方式のカラー複写機が用いられている。2. Description of the Related Art Conventionally, a plurality of image forming units are provided, and a plurality of toner images of different colors are formed in each image forming unit, and the toner images are sequentially superimposed and transferred onto the same recording material. Various image forming apparatuses for forming a color image on a recording material have been proposed, and among them, a multicolor electrophotographic color using a belt-shaped recording material carrier, that is, a recording material transport belt (transfer belt), for high-speed recording. Copiers are used.

【０００３】又、複数色のトナー像を一度、ベルト状の
中間転写体、即ち、中間転写ベルト上に転写し、次いで
記録材に一度に転写して、記録材にカラー画像を形成す
る中間転写方式の画像形成装置も種々提案されている。In addition, a plurality of color toner images are once transferred onto a belt-like intermediate transfer member, that is, an intermediate transfer belt, and then once transferred onto a recording material to form a color image on the recording material. Various types of image forming apparatuses have been proposed.

【０００４】これらの転写ベルトや中間転写ベルトに
は、ポリカーボネイト等の樹脂シートの両端をつなぎ合
わせたシームベルトを使用しているものがあるが、この
シームベルトは長期間使用していくと、継ぎ目の破断な
どが発生する問題があった。Some of these transfer belts and intermediate transfer belts use a seam belt in which both ends of a resin sheet made of polycarbonate or the like are connected. However, if this seam belt is used for a long period of time, a seam belt is formed. There was a problem that breakage etc. occurred.

【０００５】そこで最近では、ポリイミド（抵抗調整の
ためカーボン等を添加することがある）の樹脂シートの
シームレス（継ぎ目無し）ベルトからなる転写ベルトや
中間転写ベルトが出てきており、これらベルトの長寿命
化が進んでいる。[0005] Recently, transfer belts and intermediate transfer belts made of a seamless (seamless) belt made of a resin sheet of polyimide (carbon may be added for resistance adjustment) have recently emerged. The service life is progressing.

【０００６】[0006]

【発明が解決しようとする課題】しかしながら、上記従
来の転写ベルトや中間転写ベルトを用いた画像形成装置
には、次のような問題点があった。However, the image forming apparatus using the above-mentioned conventional transfer belt or intermediate transfer belt has the following problems.

【０００７】画像形成部の転写部において、転写ベルト
を挟んで像担持体と対向した転写手段に転写バイアスを
印加して、像担持体上のトナー像を転写ベルト上の記録
材に転写する際、記録材の載っている部分と記録材の載
っていない部分の電気的抵抗の違いにより、記録材端部
で回り込み電流が転写ベルト側に流れ込み、過剰な転写
電流が転写ベルトに流入する。このため、転写ベルトを
介して対向した転写手段と像担持体の間で異常放電が発
生して、転写ベルトの表面が放電劣化し、転写ベルトの
表面抵抗が著しく低下することがある。これは、小サイ
ズの記録材の連続画像形成を行う場合に特に発生しやす
い。In the transfer section of the image forming section, a transfer bias is applied to transfer means facing the image carrier with the transfer belt interposed therebetween to transfer the toner image on the image carrier to the recording material on the transfer belt. Due to the difference in electrical resistance between the portion where the recording material is placed and the portion where the recording material is not placed, the sneak current flows to the transfer belt side at the end of the recording material, and excessive transfer current flows into the transfer belt. For this reason, abnormal discharge may occur between the transfer unit and the image carrier that are opposed to each other via the transfer belt, and the surface of the transfer belt may be deteriorated by discharge and the surface resistance of the transfer belt may be significantly reduced. This is particularly likely to occur when a continuous image is formed on a small-sized recording material.

【０００８】一般に、転写ベルトに小サイズ記録材を担
持した方が、大サイズ記録材を担持したときよりも、転
写ベルトの非通紙部の面積が大きいため、抵抗の低い非
通紙部に流れる転写電流がより多くなり、記録材への十
分なトナー像の転写を得るためには、高い転写電流が必
要である。そのため、小サイズ記録材を多数枚通紙して
画像形成すると、転写ベルトに高い転写電流が長い時間
流されることになり、転写ベルトの非通紙部に放電劣化
が起こり、表面抵抗の低下を起こす。In general, when a small-size recording material is carried on a transfer belt, the area of the non-paper passing portion of the transfer belt is larger than when a large-size recording material is carried. A larger transfer current flows, and a high transfer current is required to obtain a sufficient transfer of the toner image to the recording material. Therefore, when a large number of small-size recording materials are passed through to form an image, a high transfer current is applied to the transfer belt for a long time, and discharge deterioration occurs in the non-paper passing portion of the transfer belt, thereby reducing the surface resistance. Wake up.

【０００９】その後に、大サイズ記録材（例えばフルサ
イズ記録材）への画像形成で、転写ベルトに大サイズ記
録材を担持して転写を行うと、小サイズ記録材での非通
紙部に当たる大サイズ記録材の端部で転写ベルト抵抗が
低下していることから、大サイズ記録材の端部に過剰な
電流が流れて、像担持体上のトナー像が記録材に転写さ
れずに、所謂「転写強抜け」と呼ぶ現象が発生し、記録
材に良好な画像を得ることができない。[0009] Thereafter, when an image is formed on a large-size recording material (for example, a full-size recording material) and the transfer is performed while the large-size recording material is carried on a transfer belt, the non-sheet passing portion of the small-size recording material is hit. Since the transfer belt resistance is reduced at the end of the large-size recording material, excessive current flows at the end of the large-size recording material, and the toner image on the image carrier is not transferred to the recording material. A phenomenon called so-called "strong transfer loss" occurs, and a good image cannot be obtained on a recording material.

【００１０】以上とは別に、記録材の両面へ画像形成を
行なう場合にも、転写ベルトの表面抵抗の低下による転
写の強抜けの問題が生じる。これは、記録材の１面目の
画像形成における定着工程で、記録材の１面目に離型性
オイルが付着し、記録材の２面目の画像形成時に、転写
ベルトの表面と記録材の１面目が接触した際、付着して
いる離型性オイルが転写ベルトの表面に転移することが
あるからである。[0010] Apart from the above, when images are formed on both sides of a recording material, the problem of strong transfer loss due to a decrease in the surface resistance of the transfer belt occurs. This is because, in the fixing step in the image formation of the first side of the recording material, the release oil adheres to the first side of the recording material, and when the image of the second side of the recording material is formed, the surface of the transfer belt and the first side of the recording material This is because when they come into contact with each other, the attached releasing oil may transfer to the surface of the transfer belt.

【００１１】離型性オイルが付着した転写ベルトに対
し、上記のように転写工程で高い転写電流が流れると異
常放電が発生し、転写ベルトの表面は離型性オイルが付
着していない状態よりも早く放電劣化し、表面抵抗の低
下が加速する。このため両面画像形成時には、転写ベル
トの低抵抗化がより早く発生し、それに伴う画像の強抜
けなどの画像不良も一層早く発生していた。When a high transfer current flows in the transfer step to the transfer belt to which the release oil has adhered, abnormal discharge occurs, and the surface of the transfer belt is in a state where the release oil is not adhered. Also, the discharge deteriorates quickly, and the decrease in surface resistance is accelerated. For this reason, at the time of double-sided image formation, the resistance of the transfer belt is reduced earlier, and the image defects such as the strong omission of the image are caused earlier.

【００１２】以上のような転写ベルトについてと同じよ
うな問題は、像担持体上のトナー像を一旦中間転写ベル
ト上に一次転写し、次いで中間転写ベルト上のトナー像
を中間転写ベルトに搬送された記録材に二次転写して、
記録材に画像を得る画像形成装置でも、中間転写ベルト
に対し同様に生じる。A problem similar to that of the transfer belt described above is that the toner image on the image carrier is temporarily transferred onto the intermediate transfer belt once, and then the toner image on the intermediate transfer belt is conveyed to the intermediate transfer belt. Secondary transfer to the recording material
In an image forming apparatus that obtains an image on a recording material, the same occurs for an intermediate transfer belt.

【００１３】従って、本発明の目的は、記録材担持体や
中間転写体の非通紙部や離型性オイル付着部に、転写時
の異常放電による表面抵抗の低下が発生しても、容易に
初期の高い抵抗を回復して、転写強抜け等の画像不良の
発生を確実に防止することを可能とした画像形成装置を
提供することである。Accordingly, an object of the present invention is to provide a recording medium carrier and an intermediate transfer body which can easily handle a non-sheet-passing portion or a releasable oil-adhered portion even if the surface resistance is reduced due to abnormal discharge during transfer. Another object of the present invention is to provide an image forming apparatus capable of recovering an initial high resistance and reliably preventing occurrence of image defects such as strong transfer omission.

【００１４】[0014]

【課題を解決するための手段】上記目的は本発明に係る
画像形成装置にて達成される。要約すれば、第１の本発
明によれば、トナー像が形成される像担持体と、前記像
担持体上のトナー像が直接に或いは中間転写体を介して
転写される記録材を担持搬送するベルト状の記録材担持
体と、前記記録材担持体の前記記録材を担持する表面を
研磨する研磨手段と、を有する画像形成装置において、
前記記録材の片面に画像形成する片面画像形成機能と、
前記記録材の両面に画像形成する両面画像形成機能とを
有し、両面画像形成時の前記研磨手段による前記記録材
担持体の表面の研磨時間又は研磨頻度と、片面画像形成
時の前記研磨手段による前記記録材担持体の表面の研磨
時間又は研磨頻度との比率を変えることを特徴とする画
像形成装置が提供される。一実施態様によれば、前記研
磨手段による前記記録材担持体の表面の研磨時間又は研
磨頻度は、片面画像形成時に比べて両面画像形成時の方
が、比率が高くされる。又、他の実施態様によれば、両
面画像形成時の前記研磨手段による前記記録材担持体の
表面の研磨は、常時行なう。The above object is achieved by an image forming apparatus according to the present invention. In summary, according to the first aspect of the present invention, an image bearing member on which a toner image is formed, and a recording material on which the toner image on the image bearing member is transferred directly or via an intermediate transfer member are transported. A belt-shaped recording material carrier, and polishing means for polishing a surface of the recording material carrier that carries the recording material,
A single-sided image forming function for forming an image on one side of the recording material,
A double-sided image forming function for forming an image on both sides of the recording material, a polishing time or a polishing frequency of the surface of the recording material carrier by the polishing means during double-sided image formation, and the polishing means during single-sided image formation Wherein the ratio of the polishing time or the polishing frequency of the surface of the recording material carrier is changed. According to one embodiment, the ratio of polishing time or polishing frequency of the surface of the recording material carrier by the polishing means is higher in double-sided image formation than in single-sided image formation. According to another embodiment, the surface of the recording material carrier is polished by the polishing means during double-sided image formation at all times.

【００１５】第２の本発明によれば、トナー像が形成さ
れる像担持体と、前記像担持体上のトナー像が直接に或
いは中間転写体を介して転写される記録材を担持搬送す
るベルト状の記録材担持体と、前記記録材担持体の前記
記録材を担持する表面を研磨する研磨手段と、を有する
画像形成装置において、前記研磨手段による前記記録材
担持体の表面の研磨を、前記記録材の搬送方向と直角方
向の幅に応じて研磨時間又は研磨頻度の比率を変えるこ
とを特徴とする画像形成装置が提供される。一実施態様
によれば、前記研磨手段による前記記録材担持体の表面
の研磨は、前記記録材の搬送方向と直角方向の幅が少な
いほど、時間を長く若しくは頻度を多くして行なわれ
る。According to the second aspect of the present invention, an image bearing member on which a toner image is formed and a recording material on which the toner image on the image bearing member is transferred directly or via an intermediate transfer member are carried and conveyed. In an image forming apparatus having a belt-shaped recording material carrier and a polishing unit for polishing a surface of the recording material carrier that supports the recording material, polishing the surface of the recording material carrier by the polishing unit An image forming apparatus is characterized in that a polishing time or a polishing frequency ratio is changed according to a width of the recording material in a direction perpendicular to a conveying direction. According to one embodiment, the polishing of the surface of the recording material carrier by the polishing means is performed with a longer time or with a higher frequency as the width of the recording material in the direction perpendicular to the conveying direction is smaller.

【００１６】第３の本発明によれば、トナー像が形成さ
れる像担持体と、前記像担持体上のトナー像が転写され
るベルト状の中間転写体と、前記中間転写体のトナー像
を担持する表面を研磨する研磨手段と、を有し、前記中
間転写体上のトナー像は記録材に転写される画像形成装
置において、前記記録材の片面に画像形成する片面画像
形成機能と、前記記録材の両面に画像形成する両面画像
形成機能とを有し、両面画像形成時の前記研磨手段によ
る前記中間転写体の表面の研磨時間又は研磨頻度と、片
面画像形成時の前記研磨手段による前記中間転写体の表
面の研磨時間又は研磨頻度との比率を変えることを特徴
とする画像形成装置が提供される。一実施態様によれ
ば、前記研磨手段による前記中間転写体の表面の研磨時
間又は研磨頻度は、片面画像形成時に比べて両面画像形
成時の方が、比率が高くされる。他の実施態様によれ
ば、両面画像形成時の前記研磨手段による前記中間転写
体の表面の研磨は、常時行なう。According to the third aspect of the present invention, an image bearing member on which a toner image is formed, a belt-shaped intermediate transfer member onto which the toner image on the image bearing member is transferred, and a toner image on the intermediate transfer member A polishing means for polishing the surface carrying the, the toner image on the intermediate transfer body is transferred to a recording material, in an image forming apparatus, a single-sided image forming function to form an image on one side of the recording material, A double-sided image forming function for forming an image on both sides of the recording material, and a polishing time or a polishing frequency of the surface of the intermediate transfer body by the polishing unit at the time of forming a double-sided image; An image forming apparatus is provided, wherein the ratio of the polishing time or the polishing frequency of the surface of the intermediate transfer member is changed. According to one embodiment, the polishing time or the polishing frequency of the surface of the intermediate transfer body by the polishing means is higher in the double-sided image formation than in the single-sided image formation. According to another embodiment, the surface of the intermediate transfer body is polished by the polishing means during double-sided image formation at all times.

【００１７】第４の本発明によれば、トナー像が形成さ
れる像担持体と、前記像担持体上のトナー像が転写され
るベルト状の中間転写体と、前記中間転写体のトナー像
を担持する表面を研磨する研磨手段と、を有し、前記中
間転写体上のトナー像は記録材に転写される画像形成装
置において、前記研磨手段による前記中間転写体の表面
の研磨を、前記記録材の搬送方向と直角方向の幅に応じ
て研磨時間又は研磨頻度の比率を変えることを特徴とす
る画像形成装置が提供される。一実施態様によれば、前
記研磨手段による前記中間転写体の表面の研磨は、前記
記録材の搬送方向と直角方向の幅が少ないほど、時間を
長く若しくは頻度を多くして行なわれる。According to the fourth aspect of the present invention, an image bearing member on which a toner image is formed, a belt-shaped intermediate transfer member onto which the toner image on the image bearing member is transferred, and a toner image of the intermediate transfer member A polishing means for polishing a surface carrying the toner, wherein the toner image on the intermediate transfer body is transferred to a recording material, wherein the polishing of the surface of the intermediate transfer body by the polishing means, An image forming apparatus is provided in which the ratio of the polishing time or the polishing frequency is changed according to the width of the recording material in the direction perpendicular to the conveying direction. According to one embodiment, the polishing of the surface of the intermediate transfer body by the polishing means is performed with a longer time or with a higher frequency as the width of the recording material in the direction perpendicular to the conveying direction is smaller.

【００１８】上記各本発明にて、他の実施態様によれ
ば、前記研磨手段は、前記記録材担持体の記録材を担持
する表面或いは前記中間転写体の前記トナー像を担持す
る表面に接離自在とされ且つ回転可能な研磨部材と、前
記記録材担持体或いは前記中間転写体を挟んで前記研磨
部材と対向する、前記記録材担持体或いは前記中間転写
体の裏面に接触した支持部材とを備える。このとき、前
記研磨部材は、表面が砥粒面とされるローラにて形成す
ることができる。又、前記研磨部材は、前記記録材担持
体の記録材を担持搬送する方向或いは前記中間転写体の
移動方向と順方向に駆動することができる。According to another embodiment of the present invention, the polishing means contacts the surface of the recording material carrier for supporting the recording material or the surface of the intermediate transfer member for supporting the toner image. A polishing member that is detachable and rotatable, and a support member that is in contact with the polishing member with the recording material carrier or the intermediate transfer member interposed therebetween, and is in contact with the back surface of the recording material carrier or the intermediate transfer member. Is provided. At this time, the polishing member can be formed by a roller whose surface is an abrasive surface. Further, the polishing member can be driven in a direction in which the recording material of the recording material carrier is carried and transported, or in a forward direction with respect to a moving direction of the intermediate transfer body.

【００１９】他の実施態様によれば、前記研磨手段は、
前記記録材担持体或いは前記中間転写体から前記記録材
を分離した後の前記記録材担持体或いは前記中間転写体
の位置に設置される。According to another embodiment, the polishing means comprises:
It is installed at the position of the recording material carrier or the intermediate transfer member after the recording material is separated from the recording material carrier or the intermediate transfer member.

【００２０】更に他の実施態様によれば、像担持体を複
数有し、前記複数の像担持体上に複数色のトナー像が形
成される。According to still another embodiment, a plurality of image carriers are provided, and a plurality of color toner images are formed on the plurality of image carriers.

【００２１】[0021]

【発明の実施の形態】以下、本発明に係る画像形成装置
を図面に則して更に詳しく説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

【００２２】実施例１ 図１は、本発明に係る画像形成装置の一実施例を示す構
成図、図２は、図１の画像形成装置の転写ベルト周辺を
示す拡大図である。本実施例の画像形成装置は、多重転
写方式のカラー画像形成装置に構成とされる。Embodiment 1 FIG. 1 is a structural view showing an embodiment of an image forming apparatus according to the present invention, and FIG. 2 is an enlarged view showing a periphery of a transfer belt of the image forming apparatus of FIG. The image forming apparatus of the present embodiment is configured as a multi-transfer type color image forming apparatus.

【００２３】図１及び図２に示すように、画像形成装置
内には、第１、第２、第３、第４の画像形成部Ｐａ、Ｐ
ｂ、Ｐｃ、Ｐｄが配置され、各画像形成部で帯電、潜像
形成、現像及び転写のプロセスをへて、記録材上にシア
ン、マゼンタ、イエロー、ブラックの４色の現像像、即
ち、トナー像を重畳したカラー画像が形成される。As shown in FIGS. 1 and 2, first, second, third, and fourth image forming units Pa, P are provided in the image forming apparatus.
b, Pc, and Pd are arranged, and each of the image forming units undergoes a charging, latent image forming, developing, and transferring process, and a developed image of four colors of cyan, magenta, yellow, and black on a recording material, that is, a toner A color image on which the images are superimposed is formed.

【００２４】画像形成部Ｐａ、Ｐｂ、Ｐｃ、Ｐｄは、そ
れぞれ専用の像担持体、本例では感光ドラム（ドラム状
電子写真感光体）３ａ、３ｂ、３ｃ、３ｄを具備し、各
感光ドラム３ａ、３ｂ、３ｃ、３ｄ上に各色のトナー像
が形成される。感光ドラム３ａ、３ｂ、３ｃ、３ｄに隣
接してベルト状記録材担持体、即ち、転写ベルト１３０
が設置され、感光ドラム３ａ、３ｂ、３ｃ、３ｄ上に形
成された各色のトナー像が、転写ベルト１３０上に担持
して搬送される記録材Ｐ上に重ねて転写される。この各
色のトナー像が転写された記録材Ｐは、分離帯電器３２
により転写ベルト１３０から離脱され、定着装置９で加
熱及び加圧によりトナー像が定着された後、記録画像と
して装置外に排出される。Each of the image forming sections Pa, Pb, Pc, and Pd includes a dedicated image carrier, in this example, photosensitive drums (drum-shaped electrophotographic photosensitive members) 3a, 3b, 3c, and 3d. , 3b, 3c and 3d, toner images of respective colors are formed. A belt-shaped recording material carrier, that is, a transfer belt 130 is adjacent to the photosensitive drums 3a, 3b, 3c, and 3d.
Is provided, and the toner images of the respective colors formed on the photosensitive drums 3a, 3b, 3c, and 3d are transferred onto the recording material P carried on the transfer belt 130 in a superimposed manner. The recording material P on which the toner images of each color have been transferred is separated from the separation charger 32.
After the toner image is released from the transfer belt 130 and the fixing device 9 fixes the toner image by applying heat and pressure, the toner image is discharged out of the apparatus as a recording image.

【００２５】又、両面画像形成時には、定着装置９でト
ナー像が定着された記録材Ｐを両面パスＤに進入し、両
面パスＤ内で記録材の後端から退出させて、記録材を再
び転写ベルト１３０上に供給して、記録材裏面に対し記
録材表面と同様に画像形成を行う。When forming a double-sided image, the recording material P on which the toner image has been fixed by the fixing device 9 enters the double-sided path D, exits from the trailing end of the recording material in the double-sided path D, and returns the recording material again. The recording material is supplied onto the transfer belt 130 to form an image on the back surface of the recording material in the same manner as on the front surface of the recording material.

【００２６】感光ドラム３ａ、３ｂ、３ｃ、３ｄの外周
には、それぞれ、ドラム帯電器２ａ、２ｂ、２ｃ、２
ｄ、電位センサー１１３ａ、１１３ｂ、１１３ｃ、１１
３ｄ、現像器１ａ、１ｂ、１ｃ、１ｄ、転写帯電器２４
ａ、２４ｂ、２４ｃ、２４ｄ、及びクリーナー４ａ、４
ｂ、４ｃ、４ｄが設けられ、装置の上方部には、更に図
示しない光源装置及びポリゴンミラー１１７が設置され
ている。On the outer periphery of the photosensitive drums 3a, 3b, 3c and 3d, drum chargers 2a, 2b, 2c and 2
d, potential sensors 113a, 113b, 113c, 11
3d, developing devices 1a, 1b, 1c, 1d, transfer charger 24
a, 24b, 24c, 24d and cleaners 4a, 4
b, 4c, and 4d are provided, and a light source device and a polygon mirror 117 (not shown) are further provided above the device.

【００２７】感光ドラム３ａ、３ｂ、３ｃ、３ｄは、帯
電器２ａ、２ｂ、２ｃ、２ｄにより表面が所定電位に帯
電された後、光源装置から発せられたレーザー光をポリ
ゴンミラー１１７を回転して走査し、その走査光の光束
を反射ミラーによって偏向し、図示しないｆθレンズに
より感光ドラム３ａ、３ｂ、３ｃ、３ｄの母線上に集光
して露光することにより、感光ドラム３ａ、３ｂ、３
ｃ、３ｄの表面上に各色の画像信号に応じた静電潜像が
形成される。After the surfaces of the photosensitive drums 3a, 3b, 3c and 3d are charged to a predetermined potential by the chargers 2a, 2b, 2c and 2d, the polygon mirror 117 rotates laser light emitted from the light source device. It scans, deflects the light beam of the scanning light by a reflection mirror, and condenses and exposes the light on the generatrix of the photosensitive drums 3a, 3b, 3c, and 3d by an fθ lens (not shown) to expose the photosensitive drums 3a, 3b, and 3d.
An electrostatic latent image corresponding to the image signal of each color is formed on the surfaces c and 3d.

【００２８】現像器１ａ、１ｂ、１ｃ、１ｄには、現像
剤としてそれぞれシアン、マゼンタ、イエロー、ブラッ
クのトナーが、図示しない供給装置により所定量充填さ
れている。現像器１ａ、１ｂ、１ｃ、１ｄは、それぞれ
感光ドラム３ａ、３ｂ、３ｃ、３ｄ上の潜像を現像し
て、シアントナー像、マゼンタトナー像、イエロートナ
ー像、ブラックトナー像として可視化する。The developing devices 1a, 1b, 1c and 1d are filled with a predetermined amount of cyan, magenta, yellow and black toners, respectively, as a developer by a supply device (not shown). The developing devices 1a, 1b, 1c, and 1d develop the latent images on the photosensitive drums 3a, 3b, 3c, and 3d, respectively, and visualize the latent images as cyan, magenta, yellow, and black toner images.

【００２９】記録材Ｐは記録材カセット１０に収容され
ており、そこから複数の搬送ローラ及びレジストローラ
１２を経て転写ベルト１３０上に供給され、転写ベルト
１３０上に担持される。転写ベルト１３０上に担持され
た記録材Ｐは、転写ベルト１３０の回転にともない搬送
されて、感光ドラム３ａ、３ｂ、３ｃ、３ｄと対向した
転写部に順次送られる。The recording material P is stored in a recording material cassette 10, is supplied to the transfer belt 130 via a plurality of transport rollers and registration rollers 12, and is carried on the transfer belt 130. The recording material P carried on the transfer belt 130 is conveyed with the rotation of the transfer belt 130, and is sequentially sent to a transfer unit facing the photosensitive drums 3a, 3b, 3c, and 3d.

【００３０】転写ベルト１３０は、ポリエチレンテレフ
タレート樹脂（ＰＥＴ樹脂）や、ポリフッ化ビニリデン
樹脂、ポリウレタン樹脂などの誘電体樹脂のシートから
なっており、その両端部を互いに重ね合わせて接合し、
エンドレス形状にしたものか、或いは継ぎ目を有しない
（シームレス）ベルトが用いられている。本実施例で
は、カーボンを添加して表面抵抗を１０¹³〜１０¹⁵Ω／
□に調節したポリイミド樹脂の厚さ８０μｍのベルトを
使用した。The transfer belt 130 is made of a sheet of a dielectric resin such as a polyethylene terephthalate resin (PET resin), a polyvinylidene fluoride resin, or a polyurethane resin.
Endless or seamless (seamless) belts are used. In this embodiment, the surface resistance is set to 10 ¹³ to 10 ¹⁵ Ω / by adding carbon.
An 80 μm thick belt of a polyimide resin adjusted to □ was used.

【００３１】転写ベルト１３０は、駆動ローラ１３での
駆動により矢印方向に回転し、レジストローラ１２から
送り出された記録材Ｐを担持して、第１画像形成部Ｐａ
の転写部へ向けて搬送する。これと同時に画像書き出し
信号がオンとなり、それを基準としてあるタイミングで
第１画像形成部Ｐａの感光ドラム３ａに対し画像形成を
行なう。そして感光ドラム３ａの下側の転写部で転写帯
電器２４ａが電界又は電荷を付与することにより、感光
ドラム３ａ上に形成された第１色目のトナー像が記録材
Ｐ上に転写される。この転写により記録材Ｐは転写ベル
ト１３０上に静電吸着力でしっかりと保持され、第２画
像形成部Ｐｂ以降に搬送される。転写と同時に記録材Ｐ
を転写ベルト１３０上に静電吸着するのではなく、転写
前に吸着帯電器５を設けてもよい。The transfer belt 130 is rotated in the direction of the arrow by the driving of the driving roller 13, and carries the recording material P sent from the registration roller 12 to the first image forming unit Pa.
Is conveyed to the transfer section. At the same time, the image writing signal is turned on, and an image is formed on the photosensitive drum 3a of the first image forming unit Pa at a certain timing based on the signal. Then, the transfer charger 24a applies an electric field or electric charge in the lower transfer section of the photosensitive drum 3a, so that the first color toner image formed on the photosensitive drum 3a is transferred onto the recording material P. Due to this transfer, the recording material P is firmly held on the transfer belt 130 by electrostatic attraction, and is conveyed to the second image forming portion Pb and thereafter. Recording material P at the same time as transfer
Instead of electrostatically adhering to the transfer belt 130, an adsorption charger 5 may be provided before transfer.

【００３２】転写帯電器２４（２４ａ、２４ｂ、２４
ｃ、２４ｄ）は、導電性のブレード、ローラ、ブラシ等
の帯電部材を用いた接触帯電器を用いる。接触帯電器
は、オゾンレスで温湿度環境変動の影響を受けにくく、
高画質等のメリットがある。The transfer charger 24 (24a, 24b, 24
For c and 24d), a contact charger using a charging member such as a conductive blade, a roller, or a brush is used. The contact charger is ozone-less and is less susceptible to temperature and humidity changes.
There are advantages such as high image quality.

【００３３】第２〜第４画像形成部Ｐｂ〜Ｐｄでの画像
形成、転写も第１画像形成部Ｐａと同様に行われ、この
ようにして記録材Ｐ上に４色のトナー像が重ねて転写さ
れる。次いで、記録材Ｐは、転写ベルト１３０の搬送方
向下流部で分離帯電器３２により除電して、静電吸着力
を減衰させることにより、転写ベルト１３０の末端から
離脱する。特に、低湿環境では記録材も乾燥して電気抵
抗が高くなるため、転写ベルト１３０との静電吸着力が
大きくなり、分離帯電器３２の効果は大きくなる。通
常、分離帯電器３２は、トナー像未定着の状態で記録材
Ｐに帯電するため、非接触帯電器が用いられる。Image formation and transfer in the second to fourth image forming units Pb to Pd are performed in the same manner as in the first image forming unit Pa. In this manner, four color toner images are superimposed on the recording material P. Transcribed. Next, the recording material P is removed from the end of the transfer belt 130 by removing electricity by the separation charger 32 at a downstream portion of the transfer belt 130 in the transport direction and attenuating the electrostatic attraction force. In particular, in a low-humidity environment, the recording material also dries and the electrical resistance increases, so that the electrostatic attraction force with the transfer belt 130 increases, and the effect of the separation charger 32 increases. Usually, the separation charger 32 charges the recording material P in a state where the toner image is not fixed, so that a non-contact charger is used.

【００３４】記録材Ｐの転写ベルト１３０からの離脱位
置より転写ベルト進行方向下流には、転写ベルト１３０
表面に付着した飛散トナー等をクリーニングするブレー
ド２０が常時転写ベルトに当接され、又、その下流に転
写ベルトクリーニングウェブ１９が備えられている。The transfer belt 130 is located downstream of the position where the recording material P is separated from the transfer belt 130 in the traveling direction of the transfer belt.
A blade 20 for cleaning scattered toner and the like attached to the surface is constantly in contact with the transfer belt, and a transfer belt cleaning web 19 is provided downstream of the blade.

【００３５】分離した記録材Ｐは定着装置９へと搬送さ
れ、定着によりトナー像の混色及び記録材Ｐへの固定が
行われ、フルカラーのコピー画像に形成された後、排紙
トレイ６３に排出される。The separated recording material P is conveyed to the fixing device 9, where the toner image is mixed and fixed to the recording material P by fixing to form a full-color copy image, and then discharged to the discharge tray 63. Is done.

【００３６】定着装置９は、定着ローラ５１、加圧ロー
ラ５２と、それらのクリーニング部材５４、５５と、ロ
ーラ５１、５２内に設置された加熱ヒータ５６、５７
と、定着ローラ５１にジメチルシリコーンオイル等の離
型性オイルを塗布する塗布ローラ５０と、そのオイルを
溜めておくオイル溜めトレイ５３と、加圧ローラ５２の
表面の温度を検知して定着温度を制御するサーミスタ５
８などから構成されている。The fixing device 9 includes a fixing roller 51, a pressure roller 52, cleaning members 54 and 55 thereof, and heaters 56 and 57 installed in the rollers 51 and 52.
An application roller 50 for applying a release oil such as dimethyl silicone oil to the fixing roller 51; an oil storage tray 53 for storing the oil; and a temperature of the surface of the pressure roller 52 to detect the fixing temperature. Thermistor 5 to control
8 and the like.

【００３７】さて、前述したように、転写ベルト１３０
には、非通紙部や離型性オイルの付着部における転写時
の異常放電に起因した放電劣化が生じ、表面抵抗の低下
が発生する。そこで、本発明では、表面抵抗の低下が発
生したときに容易に初期の高い抵抗を回復できるように
するために、研磨手段７０を設置して転写ベルト１３０
の表面を研磨するようにした。Now, as described above, the transfer belt 130
In this case, discharge deterioration occurs due to abnormal discharge at the time of transfer in the non-sheet passing portion or the portion where the release oil is attached, and the surface resistance decreases. Therefore, in the present invention, in order to easily recover the initial high resistance when the surface resistance is reduced, the polishing means 70 is provided and the transfer belt 130 is provided.
Was polished.

【００３８】本実施例によれば、研磨手段７０は、転写
ベルト１３０の表面を研磨する研磨ローラ７１と、転写
ベルト１３０を挟んで対向した、転写ベルト１３０の裏
面をバックアップする部材８１とを備えており、この研
磨手段７０を転写ベルト１３０の進行方向上、記録材離
脱位置の下流で吸着位置の上流側の間の位置に配置し
た。According to the present embodiment, the polishing means 70 includes the polishing roller 71 for polishing the front surface of the transfer belt 130 and the member 81 for backing up the back surface of the transfer belt 130 with the transfer belt 130 interposed therebetween. The polishing means 70 is disposed at a position downstream of the recording material separation position and upstream of the suction position in the traveling direction of the transfer belt 130.

【００３９】研磨ローラ７１は表面に砥粒面を有するロ
ーラとされ、本例では、図３に示すように、アルミパイ
プ７２を基材とし、その表面に研磨シート７３を巻き付
けて構成されている。研磨シート７３は、ラッピングフ
ィルム（３Ｍ社製）＃６００を使用した。このラッピン
グフィルムは、樹脂シートの表面上に研磨剤としてアル
ミナ粒子を一様に糊着したものである。研磨ローラ７１
の直径Ｄ１は２０ｍｍ、長手方向の長さＬ１は３３０ｍ
ｍに設定した。研磨ローラ７１は、図４に示すように、
図示しない偏心カムによる揺動で転写ベルト１３０に対
し接離自在、且つ図示しないモータによってその中心軸
線の回りに回転可能に構成した。The polishing roller 71 is a roller having an abrasive surface on its surface. In this embodiment, as shown in FIG. 3, an aluminum pipe 72 is used as a base material, and a polishing sheet 73 is wound around the surface thereof. . As the polishing sheet 73, a wrapping film (manufactured by 3M) # 600 was used. This wrapping film is obtained by uniformly gluing alumina particles as an abrasive on the surface of a resin sheet. Polishing roller 71
Has a diameter D1 of 20 mm and a longitudinal length L1 of 330 m.
m. The polishing roller 71 is, as shown in FIG.
The transfer belt 130 is configured to be freely movable toward and away from the transfer belt 130 by swinging by an eccentric cam (not shown) and to be rotatable around its central axis by a motor (not shown).

【００４０】バックアップ部材８１は、図５に示すよう
に、板金８２を基材とし、その表面にスポンジ８３を貼
り付け、スポンジ８３の表面にバックアップシート８４
を貼り付けて構成されており、シート８４側で転写ベル
ト１３０の裏面に接触して、転写ベルト表面の研磨時の
転写ベルトの支持をする。バックアップ部材８１の板金
８２及びバックアップシート８４の端部は、転写ベルト
１３０とは反対側に折り曲げられている。スポンジ８３
は、研磨時の研磨ローラ７１の転写ベルト１３０への当
接の不均一を防止するために設けられ、厚さ２ｍｍに設
定されている。バックアップシート８４は高密度ポリエ
チレンのシートからなり、その中でも滑り性の高いもの
を使用した。これは、転写ベルト１３０の走行時の駆動
負荷を軽減するためである。As shown in FIG. 5, the backup member 81 is made of a sheet metal 82 as a base material, a sponge 83 is attached to the surface thereof, and a backup sheet 84 is attached to the surface of the sponge 83.
The sheet 84 is in contact with the back surface of the transfer belt 130 to support the transfer belt when polishing the surface of the transfer belt. The ends of the sheet metal 82 and the backup sheet 84 of the backup member 81 are bent to the side opposite to the transfer belt 130. Sponge 83
Is provided to prevent uneven contact of the polishing roller 71 with the transfer belt 130 during polishing, and is set to a thickness of 2 mm. The backup sheet 84 is made of a high-density polyethylene sheet, and among them, a sheet having high slip properties is used. This is to reduce the driving load when the transfer belt 130 runs.

【００４１】本実施例の研磨手段７０による転写ベルト
１３０の研磨動作について説明する。本実施例におい
て、転写ベルト１３０の走行速度２００ｍｍ／秒に対
し、研磨ローラ７１を総圧８００ｇｆ（７．８４Ｎ）で
転写ベルト１３０当接し、転写ベルト１３０の移動方向
ａと同方向に表面が移動する向きの順方向ｂに、研磨ロ
ーラ７１を転写ベルト１３０の速度の２．４倍の周速度
４８０ｍｍ／秒（回転速度４５０ｒｐｍ）で回転させ
た。研磨ローラ７１を順方向に回転させるのは、研磨動
作時の転写ベルト１３０の駆動負荷を減らすためであ
る。この条件で転写ベルト１３０の表面を研磨したとこ
ろ、転写ベルト１３０の表面粗さは全体的に１０点平均
粗さＲｚで１〜３μｍが得られた。The operation of polishing the transfer belt 130 by the polishing means 70 of this embodiment will be described. In this embodiment, the polishing roller 71 is brought into contact with the transfer belt 130 at a total pressure of 800 gf (7.84 N) at a traveling speed of the transfer belt 130 of 200 mm / sec, and the surface moves in the same direction as the movement direction a of the transfer belt 130. In the forward direction b, the polishing roller 71 was rotated at a peripheral speed of 480 mm / sec (a rotational speed of 450 rpm) 2.4 times the speed of the transfer belt 130. The reason for rotating the polishing roller 71 in the forward direction is to reduce the driving load of the transfer belt 130 during the polishing operation. When the surface of the transfer belt 130 was polished under these conditions, the surface roughness of the transfer belt 130 was 1 to 3 μm in terms of 10-point average roughness Rz as a whole.

【００４２】転写ベルト１３０の新品状態時の表面粗さ
は、粗し処理により１０点平均粗さＲｚ＝２μｍ程度で
ある。新品状態時の転写ベルト１３０の表面抵抗率は１
〜５×１０¹⁵Ω／□（２３℃、６０％環境下、１ｋＶ印
加で測定）である。The surface roughness of the transfer belt 130 in a new state is about 10 points average roughness Rz = 2 μm due to the roughening treatment. The surface resistivity of the transfer belt 130 in a new state is 1
５5 × 10 ¹⁵ Ω / □ (measured by applying 1 kV under an environment of 23 ° C. and 60%).

【００４３】この転写ベルト１３０を表面研磨すること
なく使用して、小サイズ記録材の画像形成や記録材両面
の画像形成動作を繰り返して行くと、転写時に転写ベル
ト表面が放電劣化し、転写ベルト１３０の表面抵抗が徐
々に低下して、転写ベルト１３０の表面低効率が１×１
０¹²Ω／□程度まで低下した辺りで、転写強抜けが発生
し、画像不良となって現れた。When the transfer belt 130 is used without polishing the surface, and the image forming operation of the small-sized recording material and the image forming operation on both sides of the recording material are repeated, the surface of the transfer belt is deteriorated by discharge during the transfer, and the transfer belt is deteriorated. 130, the surface resistance of the transfer belt 130 is reduced by 1 × 1
0 ¹² Ω / □ in the neighborhood was reduced to a degree, transfer a little omission occurs and appears as a poor image.

【００４４】図６に、転写ベルト１３０に対する表面研
磨を行わずに画像形成したときの、画像形成枚数と転写
ベルト１３０の表面抵抗率の変化の関係を示す。グラフ
（Ａ）はフルサイズ（Ａ４サイズ）記録材の片面画像形
成時、グラフ（Ｂ）は小サイズ（Ｂ５Ｒサイズ）記録材
の片面画像形成時、グラフ（Ｃ）は小サイズ（Ｂ５Ｒサ
イズ）記録材の両面画像形成時ものである。これらの画
像形成は連続通紙で行なっており、全て表面抵抗率は、
Ｂ５Ｒサイズ記録材（送り方向前後端が短辺となる送り
のＢ５サイズ記録材）のスラスト方向端部位置（転写ベ
ルト中央部から１０ｃｍの位置）を測定している。FIG. 6 shows the relationship between the number of images formed and the change in the surface resistivity of the transfer belt 130 when an image is formed without polishing the surface of the transfer belt 130. Graph (A) shows a single-sided image formation of a full-size (A4 size) recording material, graph (B) shows a single-sided image formation of a small-size (B5R size) recording material, and graph (C) shows a small-size (B5R size) recording. This is the case when forming a double-sided image of the material. These images are formed by continuous paper passing, and the surface resistivity is all
The end position in the thrust direction (position 10 cm from the center of the transfer belt) of the B5R size recording material (feeding B5 size recording material whose front and rear ends are short sides) is measured.

【００４５】図６に示されるように、フルサイズ片面
（図６のＡ）では、画像形成により表面抵抗率の低下が
起きないのに対し、小サイズ片面（Ｂ）では、約５万枚
で転写強抜けが発生する表面抵抗率１０¹²Ω／□に達
し、小サイズ両面（Ｃ）では、約６千枚で達してしま
う。その後、大サイズ（フルサイズ）の記録材に画像形
成を行なうと画像不良が発生する。As shown in FIG. 6, the surface resistivity does not decrease due to image formation on one side of the full size (A in FIG. 6), whereas about 50,000 sheets on the small side (B). The surface resistivity reaches 10 ¹² Ω / □, at which strong transfer occurs, and reaches about 6,000 sheets for the small-sized double-sided (C). Thereafter, when an image is formed on a large-size (full-size) recording material, an image defect occurs.

【００４６】これは、小サイズ記録材では、大サイズ記
録材に比べ、転写ベルト側に転写電流が流れ込みやすい
ために、トナー像の十分な転写を得るには高い転写電流
が必要であり、それだけ異常放電による放電劣化が発生
しやすいからであり、放電劣化により転写ベルト１３０
の表面抵抗の低下が容易に起こる。一方、両面画像形成
では、一旦定着装置を通過して記録材表面に付着した離
型性オイルが、記録材裏面の画像形成時に転写ベルト１
３０に転移し、これが放電劣化を発生させやすいからで
ある。This is because, in the case of the small-size recording material, the transfer current is more likely to flow into the transfer belt side than in the case of the large-size recording material, so that a high transfer current is required to obtain a sufficient transfer of the toner image. This is because discharge deterioration due to abnormal discharge is likely to occur.
Easily reduces the surface resistance. On the other hand, in double-sided image formation, the releasable oil that has once passed through the fixing device and adhered to the surface of the recording material removes the transfer belt 1 during image formation on the back surface of the recording material.
This is because it is likely to cause discharge deterioration.

【００４７】いずれの場合も、転写ベルト１３０の低抵
抗化する部分は表面側、すなわち記録材を担持する側だ
けであり、表面の低抵抗化した部分を削り取れば、転写
ベルト１３０に初期と同じ高抵抗の面が現れる。そこ
で、本実施例では、上記したように、バックアップ部材
８１により転写ベルト１３０を支持しながら、研磨ロー
ラ７１により転写ベルト１３０の表面を研磨するように
した。In any case, the portion of the transfer belt 130 where the resistance is reduced is only the surface side, that is, the side on which the recording material is carried. The same high resistance surface appears. Thus, in the present embodiment, as described above, the surface of the transfer belt 130 is polished by the polishing roller 71 while the transfer belt 130 is supported by the backup member 81.

【００４８】この転写ベルト１３０の表面研磨は非画像
動作中に行う。画像形成中に研磨動作に入ると、研磨ロ
ーラ７１が転写ベルト１３０に接する衝撃で、色ズレの
ような重大な画像不良が発生する。装置本体は、研磨動
作中、待機状態に入り、画像形成動作が行なえないよう
にしておくことが好ましい。The surface polishing of the transfer belt 130 is performed during the non-image operation. When a polishing operation is started during image formation, a serious image defect such as color shift occurs due to an impact of the polishing roller 71 contacting the transfer belt 130. It is preferable that the apparatus main body enters a standby state during the polishing operation so that the image forming operation cannot be performed.

【００４９】表面研磨の頻度は、両面画像形成時は常時
とし、片面画像形成時は定期的とする。片面画像形成時
にも常時研磨を行なえば、転写ベルト表面の抵抗回復に
は最良であるが、長時間の研磨による転写ベルト１３０
の厚さ減少や、転写ベルト１３０の研磨クズで研磨ロー
ラ７１が目詰まりし、研磨能力が低下するので、これを
防ぐために片面時は定期的とする。The frequency of the surface polishing is set to be constant during double-sided image formation, and to be constant during single-sided image formation. If the polishing is always performed during the one-sided image formation, it is best to recover the resistance of the surface of the transfer belt.
The polishing roller 71 is clogged due to a decrease in the thickness of the transfer belt 130 due to a reduction in the thickness of the transfer belt 130, and the polishing ability is reduced.

【００５０】表面研磨を実施するタイミングは、前回の
研磨動作から転写ベルト１３０の回転時間が６０分を越
えた時点で、画像形成動作の終了時とする。又、転写ベ
ルト１３０に対する表面研磨は、転写ベルト１３０の１
周分以上とする。The surface polishing is performed at the end of the image forming operation when the rotation time of the transfer belt 130 exceeds 60 minutes from the previous polishing operation. The surface polishing of the transfer belt 130 is performed by the
It should be longer than the circumference.

【００５１】本実施例の一例を示せば、転写ベルト１３
０の回転時間が６０分に達した時点で、転写ベルト２周
分（転写ベルト１回転の時間が６．８秒）の１３．６秒
間、研磨を行った。その結果、転写ベルト１３０の表面
抵抗率を、初期の１０¹⁵〜５×１０¹⁵Ω／□に対し遜色
のない１０¹⁴〜１０¹⁵Ω／□に維持でき、表面抵抗の低
下に伴う転写強抜け等のない良好な画像を得ることがで
きた。As an example of this embodiment, the transfer belt 13
When the rotation time of 0 reached 60 minutes, the polishing was performed for 13.6 seconds for two rotations of the transfer belt (the time for one rotation of the transfer belt was 6.8 seconds). As a result, the surface resistivity of the transfer belt 130, the initial ^{10 15 ~5 × 10 15 Ω /} □ in no way inferior 10 ¹⁴ ~10 ¹⁵ Ω / □ can be maintained in contrast, transfer void strong with decreasing surface resistance And a good image without the like could be obtained.

【００５２】上記では、片面画像形成時と両面画像形成
時とで研磨頻度、従って、研磨時間を変えるようにした
が、研磨ローラ７１の周速度を変更可能に構成して、両
面時の研磨速度を片面時よりも速くするようにしてもよ
い。周速度を速くすれば、転写ベルト表面の単位面積当
りの研磨量が増えるので、研磨時間を長くしたのと同様
な効果が得られる。In the above description, the polishing frequency and therefore the polishing time are changed between when forming a single-sided image and when forming a double-sided image. May be made faster than in the case of one side. If the peripheral speed is increased, the polishing amount per unit area of the transfer belt surface is increased, so that the same effect as that of the polishing time is obtained.

【００５３】以上説明したように、本実施例によれば、
転写ベルト１３０の非通紙部や両面画像形成時の離型性
オイル付着部に、転写時の異常放電による表面抵抗の低
下が発生しても、研磨手段７０により転写ベルト１３０
の表面を研磨して抵抗低下部を除去するので、初期と同
じ高い抵抗を容易に回復して維持することができ、その
結果、転写強抜け等の画像不良の発生を確実に防止する
ことができる。As described above, according to the present embodiment,
Even if the surface resistance of the transfer belt 130 is reduced due to abnormal discharge during transfer on the non-sheet passing portion of the transfer belt 130 or the release oil attaching portion during double-sided image formation, the transfer belt 130 is
Since the surface of the substrate is polished to remove the reduced resistance portion, the same high resistance as in the initial stage can be easily recovered and maintained, and as a result, occurrence of image defects such as strong transfer omission can be reliably prevented. it can.

【００５４】実施例２ 本実施例は、実施例１において、記録材Ｐの片面、両面
への画像形成に関わらず、記録材Ｐの進行方向と垂直方
向の幅（スラスト幅）に応じて、研磨時間を変化させる
ように変更した。Embodiment 2 This embodiment is different from Embodiment 1 in that, regardless of whether images are formed on one side or both sides of the recording material P, the width (thrust width) of the recording material P in the direction perpendicular to the traveling direction is determined. The polishing time was changed to change.

【００５５】図７に、本実施例で行った、記録材Ｐのス
ラスト幅に応じて時間を変えて研磨を行うときの記録材
スラスト幅と１回の研磨動作時間の関係を示す。例え
ば、画像形成を行なう記録材がＡ４サイズであるとき、
記録材のスラスト幅は２９７ｍｍである。このサイズの
記録材のみに画像形成を行なったとき、転写ベルト１３
０の回転時間が６０分を超えた時点の画像形成動作終了
時に、６．８秒間（転写ベルト１周）の研磨動作を行な
うようにした。FIG. 7 shows the relationship between the recording material thrust width and the time for one polishing operation when polishing is performed in this embodiment with changing the time according to the thrust width of the recording material P. For example, when the recording material on which an image is formed is A4 size,
The thrust width of the recording material is 297 mm. When an image is formed only on a recording material of this size, the transfer belt 13
At the end of the image forming operation when the rotation time of 0 exceeds 60 minutes, the polishing operation is performed for 6.8 seconds (one round of the transfer belt).

【００５６】一方、画像形成を行なう記録材がハガキで
あるとき、記録材Ｐのスラスト幅は１００ｍｍである。
この記録材のみに画像形成を行なったとき、転写ベルト
１３０の回転時間が６０分を超えた時点の画像形成動作
終了時に、２０．４秒間（転写ベルト３周）の研磨動作
を行なうようにした。On the other hand, when the recording material on which an image is to be formed is a postcard, the thrust width of the recording material P is 100 mm.
When an image is formed only on this recording material, the polishing operation is performed for 20.4 seconds (3 rounds of the transfer belt) at the end of the image forming operation when the rotation time of the transfer belt 130 exceeds 60 minutes. .

【００５７】前記したように、小サイズ記録材の方が転
写ベルト１３０の非通紙部面積が大きく、非通紙部に流
れる転写電流がそれだけ増すので、十分なトナー像の転
写を得るために高い転写電流が必要になって、小サイズ
記録材の多数枚通紙の画像形成をすると、高い転写電流
が長い時間流されて非通紙部に放電劣化が起こり、表面
抵抗の低下を起こすからである。そこで、上記のよう
に、画像形成する記録材Ｐのサイズが小さくなるほど、
転写ベルト表面の研磨時間を長くした。As described above, since the non-sheet-passing portion area of the transfer belt 130 is larger in the small-size recording material and the transfer current flowing in the non-sheet-passing portion increases accordingly, it is necessary to obtain a sufficient toner image transfer. When a high transfer current is required and an image is formed on a large number of small-size recording materials, a high transfer current flows for a long time, causing discharge deterioration in the non-sheet passing portion and lowering the surface resistance. It is. Therefore, as described above, as the size of the recording material P on which an image is formed becomes smaller,
Polishing time of the transfer belt surface was increased.

【００５８】多種類のサイズの記録材Ｐに対し画像形成
を行なう場合には、各記録材のスラスト幅に対する転写
ベルト回転時間を全種類で積算して、これに基づき研磨
動作時間を決定して、転写ベルト１３０の回転時間が６
０分を超えた時点で、その時間だけ転写ベルト１３０の
表面を研磨する。When forming images on recording materials P of various sizes, the transfer belt rotation time with respect to the thrust width of each recording material is integrated for all types, and the polishing operation time is determined based on this. The rotation time of the transfer belt 130 is 6
When the time exceeds 0 minutes, the surface of the transfer belt 130 is polished for the time.

【００５９】本実施例では、このように、記録材Ｐのス
ラスト幅に応じて研磨時間を変えて、転写ベルト１３０
の表面を研磨した。その結果、様々なサイズの記録材に
対し画像形成を行なっても、転写ベルト１３０の表面抵
抗率を、初期の１０¹⁵〜５×１０¹⁵Ω／□に対し同等の
１０¹⁴〜１０¹⁵Ω／□に維持でき、転写ベルト１３０の
表面抵抗の低下に伴う転写強抜け等のない良好な画像を
得ることができた。In this embodiment, as described above, the polishing time is changed according to the thrust width of the recording material P, and
Was polished. As a result, even when an image is formed on recording materials of various sizes, the surface resistivity of the transfer belt 130 is changed from 10 ^{15 to} 5 × 10 ¹⁵ Ω / □, which is equivalent to 10 ¹⁴ to 10 ¹⁵ Ω / square. □, and a good image without strong transfer loss due to a decrease in the surface resistance of the transfer belt 130 could be obtained.

【００６０】実施例３ 図８は、本発明の画像形成装置の更に他の実施例を示す
概略図である。本実施例は、中間転写方式の画像形成装
置に適用した。図８において図１に付した符号と同一の
符号は同一の部材を示す。Embodiment 3 FIG. 8 is a schematic diagram showing still another embodiment of the image forming apparatus of the present invention. This embodiment is applied to an intermediate transfer type image forming apparatus. 8, the same reference numerals as those shown in FIG. 1 indicate the same members.

【００６１】本画像形成装置を概略的に説明すると、感
光ドラム３ａ、３ｂ、３ｃ、３ｄ上に各色のトナー像を
形成し、各感光ドラム３ａ、３ｂ、３ｃ、３ｄ上の各色
のトナー像を感光ドラム３ａ、３ｂ、３ｃ、３ｄに隣接
して設置されたベルト状の中間転写体としての中間転写
ベルト２０１上に、一次転写ローラ２０２ａ、２０２
ｂ、２０２ｃ、２０２ｄにより重ねて一次転写し、次い
で中間転写ベルト２０１上の４色のトナー像を、給紙カ
セット１０から中間転写ベルト２０１の二次転写部に搬
送された記録材Ｐ上に、二次転写ローラ２０４及び対向
ローラ２０５により一括して二次転写する。４色のトナ
ー像が転写された記録材Ｐは、定着装置９で加熱及び加
圧によりトナー像が定着される。The image forming apparatus will be described briefly. Toner images of each color are formed on photosensitive drums 3a, 3b, 3c, and 3d, and toner images of each color on photosensitive drums 3a, 3b, 3c, and 3d are formed. Primary transfer rollers 202a, 202 are placed on an intermediate transfer belt 201 as a belt-like intermediate transfer member installed adjacent to the photosensitive drums 3a, 3b, 3c, 3d.
b, 202c, and 202d to superimpose the primary transfer, and then transfer the four color toner images on the intermediate transfer belt 201 onto the recording material P conveyed from the paper supply cassette 10 to the secondary transfer unit of the intermediate transfer belt 201. The secondary transfer is performed collectively by the secondary transfer roller 204 and the opposing roller 205. The recording material P on which the four color toner images have been transferred is heated and pressed by the fixing device 9 to fix the toner images.

【００６２】片面画像形成を行うときは、定着後、記録
材Ｐを記録画像として装置外に排出すればよい。両面画
像形成を行うときは、定着された記録材Ｐを両面パスＤ
に進入し、両面パスＤ内で記録材の後端から退出させ
て、記録材を再び中間転写ベルト２０１の二次転写部に
供給して、記録材表面と同様、記録材裏面に対し中間転
写ベルト２０１上のトナー像を二次転写して画像形成す
る。When a one-sided image is formed, the recording material P may be discharged outside the apparatus as a recorded image after fixing. When performing double-sided image formation, the fixed recording material P is passed through a double-sided pass D
, And exits from the rear end of the recording material in the double-sided path D, and supplies the recording material to the secondary transfer portion of the intermediate transfer belt 201 again. The toner image on the belt 201 is secondarily transferred to form an image.

【００６３】本実施例でも、中間転写ベルト２０１に対
し研磨手段７０を設置した。研磨手段７０は、中間転写
ベルト２０１の進行方向上、二次転写部の下流側の位置
に配置した、中間転写ベルト２０１の表面を研磨する研
磨ローラ７１と、中間転写ベルト２０１を挟んで対向し
た、中間転写ベルト２０１の裏面を支持するバックアッ
プ部材８１とを備えて構成される。実施例１と同様、研
磨ローラ７１は、揺動手段により中間転写ベルト２０１
に接離自在、且つ図示しないモータにより中間転写ベル
ト２０１と順方向に回転可能になっている。Also in this embodiment, the polishing means 70 is provided for the intermediate transfer belt 201. The polishing means 70 is disposed at a position downstream of the secondary transfer portion in the traveling direction of the intermediate transfer belt 201, and is opposed to a polishing roller 71 for polishing the surface of the intermediate transfer belt 201 with the intermediate transfer belt 201 interposed therebetween. And a backup member 81 that supports the back surface of the intermediate transfer belt 201. As in the case of the first embodiment, the polishing roller 71 is rotated by the swinging means.
And is rotatable in the forward direction with the intermediate transfer belt 201 by a motor (not shown).

【００６４】中間転写ベルト２０１を用いた画像形成装
置においても、大サイズ記録材に比べて小サイズ記録材
の方が、二次転写時に中間転写ベルト２０１側に二次転
写ローラ２０４から二次転写電流が流れ込みやすいため
に、記録材Ｐにトナー像を十分に二次転写するには、高
い二次転写電流が必要である。このため、二次転写部で
中間転写ベルト２０１に異常放電が発生して放電劣化
し、表面抵抗の低下が起きる。Also in the image forming apparatus using the intermediate transfer belt 201, the secondary transfer roller 204 transfers the small-size recording material to the intermediate transfer belt 201 side during the secondary transfer from the secondary transfer roller 204 as compared with the large-size recording material. Since the current easily flows, a high secondary transfer current is required to sufficiently secondary transfer the toner image onto the recording material P. For this reason, abnormal discharge occurs in the intermediate transfer belt 201 in the secondary transfer portion, and the discharge is deteriorated, and the surface resistance is reduced.

【００６５】又、記録材Ｐの両面画像形成時には、一度
定着装置を通過して記録材表面に付着した離型性オイル
が、裏面の画像形成時に二次転写ローラ２０４に転移
し、それが非通紙時に中間転写ベルト２０１に転着す
る。中間転写ベルト２０１に離型性オイルが付着する
と、二次転写部において放電劣化を更に発生させやす
く、より表面抵抗の低下を起こしやすい。Further, at the time of forming a double-sided image of the recording material P, the release oil once passing through the fixing device and adhering to the surface of the recording material is transferred to the secondary transfer roller 204 at the time of forming the image on the back surface, and the non-removable oil becomes non-transferable. The sheet is transferred to the intermediate transfer belt 201 when the sheet is passed. When the releasable oil adheres to the intermediate transfer belt 201, discharge deterioration is more likely to occur in the secondary transfer portion, and the surface resistance is more likely to decrease.

【００６６】本実施例において、研磨ローラ７１により
中間転写ベルト２０１の表面を研磨して、放電劣化した
表面の抵抗低下部を除去した。その結果、中間転写ベル
ト２０１の表面抵抗率を、初期の１０¹¹Ω／□に対し同
等の１０¹⁰〜１０¹¹Ω／□に維持でき、中間転写ベルト
の表面抵抗の低下に伴う転写強抜け等のない良好な画像
を得ることができた。In the present embodiment, the surface of the intermediate transfer belt 201 was polished by the polishing roller 71 to remove a portion of the surface which had been discharged and deteriorated by resistance reduction. As a result, the surface resistivity of the intermediate transfer belt 201 can be maintained at 10 ¹⁰ to 10 ¹¹ Ω / □, which is equivalent to the initial value of 10 ¹¹ Ω / □. And a good image with no image was obtained.

【００６７】実施例４ 図９は、本発明の画像形成装置の更に他の実施例を示す
概略図である。本画像形成装置は、図８に示した実施例
３の画像形成装置において、中間転写ベルト２０１の他
に記録材担持体としての転写ベルト２１１を備えた構成
とされる。図９において、図８に示した符号と同一の符
号は同一の部材を示す。Embodiment 4 FIG. 9 is a schematic diagram showing still another embodiment of the image forming apparatus of the present invention. This image forming apparatus has a configuration in which a transfer belt 211 as a recording material carrier is provided in addition to the intermediate transfer belt 201 in the image forming apparatus of the third embodiment shown in FIG. 9, the same reference numerals as those shown in FIG. 8 indicate the same members.

【００６８】この転写ベルト２１１は、二次転写ローラ
２０４を含む２つのローラに掛け回して、中間転写ベル
ト２０１の二次転写部と定着装置９との間に設けられ、
二次転写時、二次転写ローラ２０４が転写ベルト２１１
を介して中間転写ベルト２０１に当接される。そして二
次転写部に搬送された記録材上に中間転写ベルト２０１
上の４色のトナー像が、二次転写ローラ２０４により転
写されるともに、記録材が転写ベルト２１１に静電吸着
され、定着装置９に搬送されて定着を受ける。The transfer belt 211 is wound around two rollers including the secondary transfer roller 204 and provided between the secondary transfer portion of the intermediate transfer belt 201 and the fixing device 9.
At the time of the secondary transfer, the secondary transfer roller 204 is
Through the intermediate transfer belt 201. Then, the intermediate transfer belt 201 is placed on the recording material conveyed to the secondary transfer section.
The upper four color toner images are transferred by the secondary transfer roller 204, and the recording material is electrostatically attracted to the transfer belt 211, conveyed to the fixing device 9, and fixed.

【００６９】上記の二次転写時、中間転写ベルト２０１
だけでなく、転写ベルト２１１も異常放電により表面抵
抗が低下する。そこで、中間転写ベルト２０１だけでな
く、転写ベルト２１１にも研磨ローラ７１とバックアッ
プ部材８１とを設置して、それぞれの研磨ローラ７５に
より中間転写ベルト２０１、転写ベルト２１１の表面を
研磨した。During the secondary transfer, the intermediate transfer belt 201
In addition, the surface resistance of the transfer belt 211 decreases due to abnormal discharge. Therefore, the polishing roller 71 and the backup member 81 are provided not only on the intermediate transfer belt 201 but also on the transfer belt 211, and the surfaces of the intermediate transfer belt 201 and the transfer belt 211 are polished by the respective polishing rollers 75.

【００７０】本実施例では、これにより、ベルト２０
１、２１１のいずれも表面抵抗の低下をなくすことがで
き、その結果、良好な画像を得ることができた。In the present embodiment, the belt 20
In both Examples 1 and 211, a reduction in surface resistance could be eliminated, and as a result, a good image could be obtained.

【００７１】[0071]

【発明の効果】以上説明したように、本発明によれば、
画像形成装置の記録材担持体や中間転写体の非通紙部や
離型性オイル付着部に、転写時の異常放電により表面抵
抗の低下が発生しても、研磨手段を設置して記録材担持
体の表面や中間転写体の表面を研磨して抵抗低下部を除
去する構成とし、特に、片面画像形成時と両面画像形成
時で研磨手段による研磨時間或いは研磨頻度の比率を変
える構成とするか、又は、記録材の搬送方向と直角方向
の幅により研磨手段による研磨時間或いは研磨頻度の比
率を変える構成とされるので、これら表面に容易に初期
の高い抵抗を回復して、転写強抜け等の画像不良を確実
に防止でき、良好な画像を得ることができる。As described above, according to the present invention,
Even if the surface resistance is reduced due to abnormal discharge during transfer on the non-sheet passing portion of the recording material carrier of the image forming apparatus or the intermediate transfer member or the portion where the releasable oil is attached, a polishing means is installed to set the recording material. The surface of the carrier or the surface of the intermediate transfer body is polished to remove the reduced resistance portion. In particular, the ratio of the polishing time or the polishing frequency by the polishing means is changed between single-sided image formation and double-sided image formation. Alternatively, the ratio of the polishing time or the polishing frequency by the polishing means is changed depending on the width of the recording material in the direction perpendicular to the conveying direction. And other image defects can be reliably prevented, and a good image can be obtained.

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

【図１】本発明の画像形成装置の一実施例を示す構成図
である。FIG. 1 is a configuration diagram showing an embodiment of an image forming apparatus of the present invention.

【図２】図１の装置の転写ベルト周辺を示す拡大図であ
る。FIG. 2 is an enlarged view showing the periphery of a transfer belt of the apparatus of FIG.

【図３】図１の装置に設置した研磨手段の１つの構成要
素の研磨ローラを示す斜視図である。FIG. 3 is a perspective view showing a polishing roller as one component of the polishing means installed in the apparatus of FIG. 1;

【図４】図３の研磨ローラが転写ベルトに対し離接自在
且つ回転可能であることを示す断面図である。FIG. 4 is a cross-sectional view showing that the polishing roller of FIG. 3 is rotatable and rotatable with respect to a transfer belt.

【図５】研磨手段の他の構成要素であるバックアップ部
材を示す断面図である。FIG. 5 is a sectional view showing a backup member which is another component of the polishing means.

【図６】転写ベルト表面の研磨を行わないときの画像形
成枚数とベルトの表面抵抗率の変化の関係を示す説明図
である。FIG. 6 is an explanatory diagram showing the relationship between the number of formed images and the change in the surface resistivity of the belt when the surface of the transfer belt is not polished.

【図７】本発明の他の実施例で行った研磨での記録材ス
ラスト幅と１回の研磨動作時間の関係を示す説明図であ
る。FIG. 7 is an explanatory diagram showing a relationship between a recording material thrust width in polishing performed in another embodiment of the present invention and a single polishing operation time.

【図８】本発明の画像形成装置の更に他の実施例を示す
概略図である。FIG. 8 is a schematic diagram showing still another embodiment of the image forming apparatus of the present invention.

【図９】本発明の画像形成装置の更に他の実施例を示す
概略図である。FIG. 9 is a schematic view showing still another embodiment of the image forming apparatus of the present invention.

【符号の説明】[Explanation of symbols]

３ａ〜３ｄ 感光ドラム（像担持体） ２４ａ〜２４ｄ 転写帯電器 ７０ 研磨手段 ７１ 研磨ローラ ７３ 研磨シート ８１ バックアップ部材 １３０ 転写ベルト（記録材担持
体） ２０１ 中間転写ベルト（中間転写
体） ２０４ 二次転写ローラ ２１１ 転写ベルト（記録材担持
体）3a to 3d Photosensitive Drum (Image Carrier) 24a to 24d Transfer Charger 70 Polishing Means 71 Polishing Roller 73 Polishing Sheet 81 Backup Member 130 Transfer Belt (Recording Material Carrier) 201 Intermediate Transfer Belt (Intermediate Transfer Body) 204 Secondary Transfer Roller 211 Transfer belt (recording material carrier)

フロントページの続き (72)発明者 葛見 徹 東京都大田区下丸子３丁目30番２号 キヤ ノン株式会社内 Ｆターム(参考） 2H027 DA39 DA41 FA11 FA35 HB02 HB19 2H028 BB02 2H030 AB02 AD06 BB42 BB44 BB46 BB56 2H032 AA05 AA15 BA09 BA18 BA30 CA04 CA13 Continuation of the front page (72) Inventor Toru Katsumi 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H027 DA39 DA41 FA11 FA35 HB02 HB19 2H028 BB02 2H030 AB02 AD06 BB42 BB44 BB46 BB56 2H032 AA05 AA15 BA09 BA18 BA30 CA04 CA13

Claims (20)

【特許請求の範囲】[Claims] 【請求項１】 トナー像が形成される像担持体と、前記
像担持体上のトナー像が直接に或いは中間転写体を介し
て転写される記録材を担持搬送するベルト状の記録材担
持体と、前記記録材担持体の前記記録材を担持する表面
を研磨する研磨手段と、を有する画像形成装置におい
て、 前記記録材の片面に画像形成する片面画像形成機能と、
前記記録材の両面に画像形成する両面画像形成機能とを
有し、両面画像形成時の前記研磨手段による前記記録材
担持体の表面の研磨時間又は研磨頻度と、片面画像形成
時の前記研磨手段による前記記録材担持体の表面の研磨
時間又は研磨頻度との比率を変えることを特徴とする画
像形成装置。An image carrier on which a toner image is formed, and a belt-shaped recording material carrier for carrying and transporting a recording material on which the toner image on the image carrier is transferred directly or via an intermediate transfer member. A polishing means for polishing a surface of the recording material carrier that supports the recording material; and a single-sided image forming function of forming an image on one surface of the recording material,
A double-sided image forming function for forming an image on both sides of the recording material, a polishing time or a polishing frequency of the surface of the recording material carrier by the polishing means during double-sided image formation, and the polishing means during single-sided image formation An image forming apparatus, wherein the ratio of the polishing time or the polishing frequency of the surface of the recording material carrier is changed. 【請求項２】 前記研磨手段による前記記録材担持体の
表面の研磨時間又は研磨頻度は、片面画像形成時に比べ
て両面画像形成時の方が、比率が高いことを特徴とする
請求項１の画像形成装置。2. The polishing apparatus according to claim 1, wherein a polishing time or a polishing frequency of the surface of the recording material carrier by the polishing means is higher in double-sided image formation than in single-sided image formation. Image forming device. 【請求項３】 両面画像形成時の前記研磨手段による前
記記録材担持体の表面の研磨は、常時行なうことを特徴
とする請求項１又は２の画像形成装置。3. The image forming apparatus according to claim 1, wherein the surface of the recording material carrier is polished by the polishing means during double-sided image formation. 【請求項４】 トナー像が形成される像担持体と、前記
像担持体上のトナー像が直接に或いは中間転写体を介し
て転写される記録材を担持搬送するベルト状の記録材担
持体と、前記記録材担持体の前記記録材を担持する表面
を研磨する研磨手段と、を有する画像形成装置におい
て、 前記研磨手段による前記記録材担持体の表面の研磨を、
前記記録材の搬送方向と直角方向の幅に応じて研磨時間
又は研磨頻度の比率を変えることを特徴とする画像形成
装置。4. A belt-shaped recording material carrier for carrying a recording material on which a toner image is formed and a recording material on which the toner image is transferred directly or via an intermediate transfer member. An image forming apparatus comprising: a polishing unit configured to polish a surface of the recording material carrier that supports the recording material; and polishing the surface of the recording material carrier by the polishing unit.
An image forming apparatus, wherein a ratio of a polishing time or a polishing frequency is changed in accordance with a width of the recording material in a direction perpendicular to a conveying direction. 【請求項５】 前記研磨手段による前記記録材担持体の
表面の研磨は、前記記録材の搬送方向と直角方向の幅が
少ないほど、時間を長く若しくは頻度を多くして行うこ
とを特徴とする請求項４の画像形成装置。5. The polishing of the surface of the recording material carrier by the polishing means is performed with a longer time or a higher frequency as the width of the recording material in the direction perpendicular to the conveying direction is smaller. The image forming apparatus according to claim 4. 【請求項６】 前記研磨手段は、前記記録材担持体の前
記記録材を担持する表面に接離自在とされ且つ回転可能
な研磨部材と、前記記録材担持体を挟んで前記研磨部材
と対向する、前記記録材担持体の裏面に接触した支持部
材とを備えることを特徴とする請求項１〜５のいずれか
の項に記載の画像形成装置。6. A polishing member, which is rotatable and rotatable on a surface of the recording material carrier that supports the recording material, and is rotatable, and opposes the polishing member with the recording material carrier interposed therebetween. The image forming apparatus according to claim 1, further comprising: a support member that contacts a back surface of the recording material carrier. 【請求項７】 前記研磨部材は、表面が砥粒面とされる
ローラにて形成されることを特徴とする請求項６の画像
形成装置。7. The image forming apparatus according to claim 6, wherein the polishing member is formed by a roller whose surface is an abrasive surface. 【請求項８】 前記研磨部材は、前記記録材担持体の前
記記録材を担持搬送する移動方向と順方向に駆動される
ことを特徴とする請求項６又は７の画像形成装置。8. The image forming apparatus according to claim 6, wherein the polishing member is driven in a forward direction with respect to a moving direction of the recording material carrier to carry and convey the recording material. 【請求項９】 前記研磨手段は、前記記録材担持体から
前記記録材を分離した後の前記記録材担持体の位置に設
置されることを特徴とする請求項１〜８のいずれかの項
に記載の画像形成装置。9. The polishing apparatus according to claim 1, wherein said polishing means is provided at a position of said recording material carrier after separating said recording material from said recording material carrier. An image forming apparatus according to claim 1. 【請求項１０】 像担持体を複数有し、前記複数の像担
持体上に複数色のトナー像が形成されることを特徴とす
る請求項１〜９のいずれかの項に記載の画像形成装置。10. The image forming apparatus according to claim 1, wherein a plurality of image carriers are provided, and a plurality of color toner images are formed on the plurality of image carriers. apparatus. 【請求項１１】 トナー像が形成される像担持体と、前
記像担持体上のトナー像が転写されるベルト状の中間転
写体と、前記中間転写体のトナー像を担持する表面を研
磨する研磨手段と、を有し、前記中間転写体上のトナー
像は記録材に転写される画像形成装置において、 前記記録材の片面に画像形成する片面画像形成機能と、
前記記録材の両面に画像形成する両面画像形成機能とを
有し、両面画像形成時の前記研磨手段による前記中間転
写体の表面の研磨時間又は研磨頻度と、片面画像形成時
の前記研磨手段による前記中間転写体の表面の研磨時間
又は研磨頻度との比率を変えることを特徴とする画像形
成装置。11. An image bearing member on which a toner image is formed, a belt-shaped intermediate transfer member onto which the toner image is transferred on the image bearing member, and a surface of the intermediate transfer member bearing the toner image. A polishing unit, wherein the toner image on the intermediate transfer body is transferred to a recording material, an image forming apparatus, wherein a single-sided image forming function of forming an image on one side of the recording material;
A double-sided image forming function for forming an image on both sides of the recording material, and a polishing time or a polishing frequency of the surface of the intermediate transfer body by the polishing unit at the time of forming a double-sided image; An image forming apparatus, wherein the ratio of the polishing time or the polishing frequency of the surface of the intermediate transfer member is changed. 【請求項１２】 前記研磨手段による前記中間転写体の
表面の研磨時間又は研磨頻度は、片面画像形成時に比べ
て両面画像形成時の方が、比率が高いことを特徴とする
請求項１１の画像形成装置。12. The image according to claim 11, wherein a polishing time or a polishing frequency of the surface of the intermediate transfer body by the polishing means is higher in double-sided image formation than in single-sided image formation. Forming equipment. 【請求項１３】 両面画像形成時の前記研磨手段による
前記中間転写体の表面の研磨は、常時行なうことを特徴
とする請求項１１又は１２の画像形成装置。13. The image forming apparatus according to claim 11, wherein the polishing of the surface of the intermediate transfer body by the polishing means during double-sided image formation is always performed. 【請求項１４】 トナー像が形成される像担持体と、前
記像担持体上のトナー像が転写されるベルト状の中間転
写体と、前記中間転写体のトナー像を担持する表面を研
磨する研磨手段と、を有し、前記中間転写体上のトナー
像は記録材に転写される画像形成装置において、 前記研磨手段による前記中間転写体の表面の研磨を、前
記記録材の搬送方向と直角方向の幅に応じて研磨時間又
は研磨頻度の比率を変えることを特徴とする画像形成装
置。14. An image bearing member on which a toner image is formed, a belt-shaped intermediate transfer member onto which the toner image is transferred on the image bearing member, and a surface of the intermediate transfer member bearing the toner image. Polishing means for transferring the toner image on the intermediate transfer body to a recording material, wherein the polishing of the surface of the intermediate transfer body by the polishing means is perpendicular to the conveying direction of the recording material. An image forming apparatus wherein a ratio of a polishing time or a polishing frequency is changed according to a width in a direction. 【請求項１５】 前記研磨手段による前記中間転写体の
表面の研磨は、前記記録材の搬送方向と直角方向の幅が
少ないほど、時間を長く若しくは頻度を多くして行うこ
とを特徴とする請求項１４の画像形成装置。15. The polishing of the surface of the intermediate transfer body by the polishing means is performed with a longer time or with a greater frequency as the width of the recording material in the direction perpendicular to the conveying direction is smaller. Item 15. The image forming apparatus according to Item 14. 【請求項１６】 前記研磨手段は、前記中間転写体の前
記トナー像を担持する表面に接離自在とされ且つ回転可
能な研磨部材と、前記中間転写体を挟んで前記研磨部材
と対向する、前記中間転写体の裏面に接触した支持部材
とを備えることを特徴とする請求項１１〜１５のいずれ
かの項に記載の画像形成装置。16. A polishing member, which is rotatable and rotatable on a surface of the intermediate transfer member carrying the toner image and is rotatable, and faces the polishing member with the intermediate transfer member interposed therebetween. The image forming apparatus according to claim 11, further comprising: a support member that contacts a back surface of the intermediate transfer body. 【請求項１７】 前記研磨部材は、表面が砥粒面とされ
るローラにて形成されることを特徴とする請求項１６の
画像形成装置。17. The image forming apparatus according to claim 16, wherein the polishing member is formed by a roller whose surface is an abrasive surface. 【請求項１８】 前記研磨部材は、前記中間転写体の移
動方向と順方向に駆動されることを特徴とする請求項１
６又は１７の画像形成装置。18. The apparatus according to claim 1, wherein the polishing member is driven in a forward direction with respect to a moving direction of the intermediate transfer body.
The image forming apparatus according to 6 or 17. 【請求項１９】 前記研磨手段は、前記中間転写体から
前記記録材を分離した後の前記中間転写体の位置に設置
されることを特徴とする請求項１１〜１８のいずれかの
項に記載の画像形成装置。19. The apparatus according to claim 11, wherein said polishing means is provided at a position of said intermediate transfer member after separating said recording material from said intermediate transfer member. Image forming apparatus. 【請求項２０】 像担持体を複数有し、前記複数の像担
持体上に複数色のトナー像が形成されることを特徴とす
る請求項１１〜１９のいずれかの項に記載の画像形成装
置。20. The image forming apparatus according to claim 11, wherein a plurality of image carriers are provided, and a plurality of color toner images are formed on the plurality of image carriers. apparatus.