JP6892628B2

JP6892628B2 - Belt device and image forming device

Info

Publication number: JP6892628B2
Application number: JP2017030652A
Authority: JP
Inventors: 拓也秋山; 坂下　武司; 武司坂下; 目黒　雄二; 雄二目黒
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 2017-02-22
Filing date: 2017-02-22
Publication date: 2021-06-23
Anticipated expiration: 2037-02-22
Also published as: JP2018136436A

Description

この発明は、中間転写ベルト、転写搬送ベルト、感光体ベルト、定着ベルト等のベルト部材が所定方向に走行されるベルト装置と、それを備えた複写機、プリンタ、ファクシミリ、又は、それらの複合機等の画像形成装置と、に関するものである。 The present invention relates to a belt device in which belt members such as an intermediate transfer belt, a transfer transfer belt, a photoconductor belt, and a fixing belt travel in a predetermined direction, and a copying machine, a printer, a facsimile, or a combination machine thereof provided with the belt device. Etc., and the image forming apparatus.

従来から、複写機やプリンタ等の画像形成装置では、中間転写ベルト（ベルト部材）のベルト寄りを防止するために、中間転写ベルトの表面を押さえ部材（弾性部材）によって押圧する技術が知られている（例えば、特許文献１参照。）。 Conventionally, in image forming devices such as copiers and printers, a technique of pressing the surface of an intermediate transfer belt (belt member) with a pressing member (elastic member) has been known in order to prevent the intermediate transfer belt (belt member) from approaching the belt. (See, for example, Patent Document 1).

詳しくは、特許文献１において、押さえ部材（弾性部材）は、スポンジやフェルトなどの弾性材料で形成されていて、ホルダ（保持部材）に保持されている。そして、押さえ部材は、所定方向に走行する中間転写ベルトの表面に画像領域外で摺接するように設置されている。 Specifically, in Patent Document 1, the pressing member (elastic member) is formed of an elastic material such as sponge or felt, and is held by a holder (holding member). The pressing member is installed so as to be in sliding contact with the surface of the intermediate transfer belt traveling in a predetermined direction outside the image region.

上述した特許文献１の画像形成装置は、ベルト部材（中間転写ベルト）に摺接することによって、弾性部材（押さえ部材）が変形して、弾性部材の上流側端部がベルト部材に巻き込まれてしまう不具合が生じる可能性があった。そして、そのような不具合が生じてしまうと、弾性部材が保持部材（ホルダ）から剥がれて破損してしまったり、剥がれた弾性部材によってベルト部材が破損してしまったりすることになる。 In the image forming apparatus of Patent Document 1 described above, the elastic member (holding member) is deformed by sliding contact with the belt member (intermediate transfer belt), and the upstream end portion of the elastic member is caught in the belt member. There was a possibility of malfunction. If such a defect occurs, the elastic member may be peeled off from the holding member (holder) and damaged, or the belt member may be damaged by the peeled elastic member.

この発明は、上述のような課題を解決するためになされたもので、ベルト部材に摺接する弾性部材がベルト部材に巻き込まれてしまう不具合が生じにくい、ベルト装置、及び、画像形成装置を提供することにある。 The present invention has been made to solve the above-mentioned problems, and provides a belt device and an image forming device that are less likely to cause a problem that an elastic member that is in sliding contact with the belt member is caught in the belt member. There is.

この発明におけるベルト装置は、所定の走行方向に走行するベルト部材と、前記ベルト部材のベルト寄りを規制するために前記ベルト部材の表面に当接する弾性部材と、前記弾性部材を保持する保持部材と、を備え、前記弾性部材は、前記走行方向の上流側端部が前記ベルト部材の表面に当接しないように、Ｃ面状の面取り部が形成されたものである。 The belt device according to the present invention includes a belt member that travels in a predetermined traveling direction, an elastic member that abuts on the surface of the belt member in order to regulate the belt deviation of the belt member, and a holding member that holds the elastic member. The elastic member is formed with a C-plane chamfered portion so that the upstream end portion in the traveling direction does not abut on the surface of the belt member.

本発明によれば、ベルト部材に摺接する弾性部材がベルト部材に巻き込まれてしまう不具合が生じにくい、ベルト装置、及び、画像形成装置を提供することができる。 According to the present invention, it is possible to provide a belt device and an image forming device that are less likely to cause a problem that an elastic member that is in sliding contact with the belt member is caught in the belt member.

この発明の実施の形態における画像形成装置を示す全体構成図である。It is an overall block diagram which shows the image forming apparatus in embodiment of this invention. 中間転写ベルト装置を示す構成図である。It is a block diagram which shows the intermediate transfer belt apparatus. 中間転写ベルト装置の要部を図２のＡ視方向にみた概略図である。It is the schematic which looked at the main part of the intermediate transfer belt apparatus in the A viewing direction of FIG. 中間転写ベルト装置の要部を図３のＢ視方向にみた概略拡大図である。It is a schematic enlarged view which looked at the main part of the intermediate transfer belt apparatus in the B view direction of FIG. 比較例としての、中間転写ベルト装置の要部を示す概略拡大図である。It is a schematic enlarged view which shows the main part of the intermediate transfer belt apparatus as a comparative example. 変形例としての、中間転写ベルト装置の要部を示す概略拡大図である。It is a schematic enlarged view which shows the main part of the intermediate transfer belt apparatus as a modification. 比較例と実施例１〜４との実験結果を示す表図である。It is a chart which shows the experimental result of a comparative example and Examples 1 to 4.

以下、この発明を実施するための形態について、図面を参照して詳細に説明する。なお、各図中、同一又は相当する部分には同一の符号を付しており、その重複説明は適宜に簡略化ないし省略する。 Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and the duplicated description thereof will be appropriately simplified or omitted.

まず、図１にて、画像形成装置１００における全体の構成・動作について説明する。
図１に示すように、画像形成装置本体１００の中央には、ベルト装置としての中間転写ベルト装置１５が設置されている。また、中間転写ベルト装置１５の中間転写ベルト８（ベルト部材）に対向するように、各色（イエロー、マゼンタ、シアン、ブラック）に対応したプロセスカートリッジ６Ｙ、６Ｍ、６Ｃ、６Ｋが並設されている。 First, FIG. 1 describes the overall configuration and operation of the image forming apparatus 100.
As shown in FIG. 1, an intermediate transfer belt device 15 as a belt device is installed in the center of the image forming apparatus main body 100. Further, process cartridges 6Y, 6M, 6C, and 6K corresponding to each color (yellow, magenta, cyan, and black) are arranged side by side so as to face the intermediate transfer belt 8 (belt member) of the intermediate transfer belt device 15. ..

図１を参照して、ブラックに対応したプロセスカートリッジ６Ｋは、感光体ドラム１Ｋ（感光体）と、感光体ドラム１Ｋの周囲に配設された帯電装置４（帯電部）、現像装置５（現像部）、クリーニング装置２（クリーニング部）、除電部（不図示である。）等と、が１つのユニットとして画像形成装置本体１００に対して着脱可能（交換可能）に構成されている。そして、感光体ドラム１Ｋの表面で、作像プロセス（帯電工程、露光工程、現像工程、転写工程、クリーニング工程）がおこなわれて、感光体ドラム１Ｋの表面にブラック画像が形成されることになる。すなわち、プロセスカートリッジ６Ｋは、１次転写ローラ９Ｋ（転写部材）などとともに、作像部を構成している。 With reference to FIG. 1, the process cartridge 6K corresponding to black includes a photoconductor drum 1K (photoreceptor), a charging device 4 (charging unit) arranged around the photoconductor drum 1K, and a developing device 5 (development). A unit), a cleaning device 2 (cleaning unit), a static elimination unit (not shown), and the like are configured to be removable (replaceable) with respect to the image forming apparatus main body 100 as one unit. Then, an image forming process (charging step, exposure step, developing step, transfer step, cleaning step) is performed on the surface of the photoconductor drum 1K, and a black image is formed on the surface of the photoconductor drum 1K. .. That is, the process cartridge 6K constitutes an image-creating unit together with the primary transfer roller 9K (transfer member) and the like.

なお、他の３つのプロセスカートリッジ６Ｙ、６Ｍ、６Ｃ（作像部）も、使用されるトナーの色が異なる以外は、ブラックに対応したプロセスカートリッジ６Ｋ（作像部）とほぼ同様の構成となっていて、それぞれのトナー色に対応した画像が形成される。以下、他の３つのプロセスカートリッジ６Ｙ、６Ｍ、６Ｃ（作像部）の説明を適宜に省略して、ブラックに対応したプロセスカートリッジ６Ｋ（作像部）のみの説明をおこなうことにする。 The other three process cartridges 6Y, 6M, and 6C (image forming part) have almost the same configuration as the process cartridge 6K (image forming part) corresponding to black, except that the color of the toner used is different. An image corresponding to each toner color is formed. Hereinafter, the description of the other three process cartridges 6Y, 6M, and 6C (image forming section) will be omitted as appropriate, and only the process cartridge 6K (image forming section) corresponding to black will be described.

図１を参照して、感光体ドラム１Ｋは、メインモータによって時計方向に回転駆動される。そして、帯電装置４（帯電ローラ）の位置で、感光体ドラム１Ｋの表面が一様に帯電される（帯電工程である。）。
その後、感光体ドラム１Ｋの表面は、露光部７（光書込ヘッド）から発せられた露光光の照射位置に達して、この位置での露光走査によってブラックに対応した静電潜像が形成される（露光工程である。）。 With reference to FIG. 1, the photoconductor drum 1K is rotationally driven clockwise by the main motor. Then, the surface of the photoconductor drum 1K is uniformly charged at the position of the charging device 4 (charging roller) (the charging step).
After that, the surface of the photoconductor drum 1K reaches the irradiation position of the exposure light emitted from the exposure unit 7 (optical writing head), and an electrostatic latent image corresponding to black is formed by exposure scanning at this position. (It is an exposure process).

その後、感光体ドラム１Ｋの表面は、現像装置５との対向位置（現像ニップ）に達して、この位置で静電潜像が現像されて、ブラックのトナー像が形成される（現像工程である。）。
その後、感光体ドラム１Ｋの表面は、中間転写ベルト８及び１次転写ローラ９Ｋとの対向位置に達して、この位置で感光体ドラム１Ｋ上のトナー像が中間転写ベルト８（ベルト部材）上に転写される（１次転写工程である。）。このとき、感光体ドラム１Ｋ上には、僅かながら未転写トナーが残存する。 After that, the surface of the photoconductor drum 1K reaches a position facing the developing device 5 (development nip), and the electrostatic latent image is developed at this position to form a black toner image (development step). .).
After that, the surface of the photoconductor drum 1K reaches a position facing the intermediate transfer belt 8 and the primary transfer roller 9K, and at this position, the toner image on the photoconductor drum 1K is placed on the intermediate transfer belt 8 (belt member). It is transferred (it is a primary transfer step). At this time, a small amount of untransferred toner remains on the photoconductor drum 1K.

その後、感光体ドラム１Ｋの表面は、クリーニング装置２との対向位置に達して、この位置で感光体ドラム１Ｋ上に残存した未転写トナーがクリーニングブレードによってクリーニング装置２内に回収される（クリーニング工程である。）。
最後に、感光体ドラム１Ｋの表面は、除電部との対向位置に達して、この位置で感光体ドラム１Ｋ上の残留電位が除去される。
こうして、感光体ドラム１Ｋ上でおこなわれる、一連の作像プロセスが終了する。 After that, the surface of the photoconductor drum 1K reaches a position facing the cleaning device 2, and the untransferred toner remaining on the photoconductor drum 1K at this position is collected in the cleaning device 2 by the cleaning blade (cleaning step). It is.).
Finally, the surface of the photoconductor drum 1K reaches a position facing the static elimination portion, and the residual potential on the photoconductor drum 1K is removed at this position.
In this way, a series of image forming processes performed on the photoconductor drum 1K is completed.

なお、上述した作像プロセスは、他のプロセスカートリッジ６Ｙ、６Ｍ、６Ｃ（作像部）でも、ブラック用のプロセスカートリッジ６Ｋ（作像部）と同様におこなわれる。すなわち、作像部の上方に配設された露光部から、画像情報に基いた露光光が、各プロセスカートリッジ６Ｙ、６Ｍ、６Ｃの感光体ドラム１Ｙ、１Ｍ、１Ｃ上に向けて照射される。
その後、現像工程を経て各感光体ドラム１Ｙ、１Ｍ、１Ｃ、１Ｋ上に形成した各色のトナー像を、中間転写ベルト８上に重ねて転写する。こうして、中間転写ベルト８上にカラー画像が形成される。 The above-mentioned image forming process is also performed on the other process cartridges 6Y, 6M, and 6C (image forming section) in the same manner as on the black process cartridge 6K (image forming section). That is, the exposure light based on the image information is emitted from the exposure unit arranged above the image-creating unit toward the photoconductor drums 1Y, 1M, and 1C of the process cartridges 6Y, 6M, and 6C.
Then, the toner images of each color formed on the photoconductor drums 1Y, 1M, 1C, and 1K through the developing process are superimposed and transferred on the intermediate transfer belt 8. In this way, a color image is formed on the intermediate transfer belt 8.

ここで、図２を参照して、中間転写ベルト装置１５は、ベルト部材としての中間転写ベルト８、４つの転写部材としての１次転写ローラ９Ｙ、９Ｍ、９Ｃ、９Ｋ、ローラ部材としての駆動ローラ１０、従動ローラ１１、テンションローラ１２、等で構成される。中間転写ベルト８は、複数のローラ（駆動ローラ１０と従動ローラ１１と１次転写ローラ９Ｙ、９Ｍ、９Ｃ、９Ｋとである。）によって張架・支持されるとともに、駆動モータ４０による駆動ローラ１０の回転駆動によって図１、図２の矢印方向（反時計方向）に無端移動される。 Here, referring to FIG. 2, the intermediate transfer belt device 15 includes an intermediate transfer belt 8 as a belt member, four primary transfer rollers 9Y, 9M, 9C, 9K as transfer members, and a drive roller as a roller member. 10. It is composed of a driven roller 11, a tension roller 12, and the like. The intermediate transfer belt 8 is stretched and supported by a plurality of rollers (driving roller 10, driven roller 11, and primary transfer roller 9Y, 9M, 9C, 9K), and the driving roller 10 is driven by the drive motor 40. Is moved endlessly in the direction of the arrows (counterclockwise) in FIGS. 1 and 2 by the rotational drive of.

１次転写ローラ９Ｙ、９Ｍ、９Ｃ、９Ｋは、それぞれ、中間転写ベルト８を各感光体ドラム１Ｙ、１Ｍ、１Ｃ、１Ｋとの間に挟み込んで１次転写ニップ部（転写位置）を形成している。そして、１次転写ローラ９Ｙ、９Ｍ、９Ｃ、９Ｋに、それぞれ、トナーの極性とは逆の転写電圧（１次転写バイアス）が印加される。
そして、中間転写ベルト８は、矢印方向に走行して、各１次転写ローラ９Ｙ、９Ｍ、９Ｃ、９Ｋの１次転写ニップ部を順次通過する。こうして、各感光体ドラム１Ｙ、１Ｍ、１Ｃ、１Ｋの表面に形成された各色のトナー像が、中間転写ベルト８上に重ねて１次転写される。 The primary transfer rollers 9Y, 9M, 9C, and 9K each sandwich the intermediate transfer belt 8 between the photoconductor drums 1Y, 1M, 1C, and 1K to form a primary transfer nip portion (transfer position). There is. Then, a transfer voltage (primary transfer bias) opposite to the polarity of the toner is applied to the primary transfer rollers 9Y, 9M, 9C, and 9K, respectively.
Then, the intermediate transfer belt 8 travels in the direction of the arrow and sequentially passes through the primary transfer nip portions of the primary transfer rollers 9Y, 9M, 9C, and 9K, respectively. In this way, the toner images of each color formed on the surfaces of the photoconductor drums 1Y, 1M, 1C, and 1K are superposed on the intermediate transfer belt 8 and first-order transferred.

その後、各色のトナー像が重ねて転写された中間転写ベルト８は、２次転写ローラ１９（２次転写部材）との対向位置に達する。この位置では、駆動ローラ１０が、２次転写ローラ１９との間に中間転写ベルト８を挟み込んで２次転写ニップ部を形成している。そして、中間転写ベルト８上に形成された４色のトナー像は、この２次転写ニップ部の位置に搬送された転写紙等のシートＰ上に転写される（２次転写工程である。）。このとき、中間転写ベルト８には、シートＰに転写されなかった未転写トナーが残存する。 After that, the intermediate transfer belt 8 on which the toner images of each color are superimposed and transferred reaches a position facing the secondary transfer roller 19 (secondary transfer member). At this position, the drive roller 10 sandwiches the intermediate transfer belt 8 with the secondary transfer roller 19 to form a secondary transfer nip portion. Then, the four-color toner images formed on the intermediate transfer belt 8 are transferred onto a sheet P such as transfer paper conveyed to the position of the secondary transfer nip portion (this is a secondary transfer step). .. At this time, untransferred toner that has not been transferred to the sheet P remains on the intermediate transfer belt 8.

その後、中間転写ベルト８は、中間転写クリーニング装置１６（中間転写クリーニングブレード）の位置に達する。そして、この位置で、中間転写ベルト８上の未転写トナーが、中間転写ベルト８に圧接する中間転写クリーニングブレード（中間転写クリーニング装置１６）によって機械的に除去される。なお、中間転写クリーニングブレードは、ウレタンゴム等の弾性材料で形成された略板状部材であって、中間転写ベルト８に対して所定の当接圧及び当接角で当接している。
こうして、中間転写ベルト８上でおこなわれる、一連の転写プロセスが終了する。
なお、中間転写クリーニング装置１６の位置を通過した中間転写ベルト８の位置には、テンションローラ１２が中間転写ベルト８の外周面に当接するように設置されている。 After that, the intermediate transfer belt 8 reaches the position of the intermediate transfer cleaning device 16 (intermediate transfer cleaning blade). Then, at this position, the untransferred toner on the intermediate transfer belt 8 is mechanically removed by the intermediate transfer cleaning blade (intermediate transfer cleaning device 16) that press-contacts the intermediate transfer belt 8. The intermediate transfer cleaning blade is a substantially plate-shaped member made of an elastic material such as urethane rubber, and is in contact with the intermediate transfer belt 8 at a predetermined contact pressure and contact angle.
In this way, a series of transfer processes performed on the intermediate transfer belt 8 is completed.
The tension roller 12 is installed at the position of the intermediate transfer belt 8 that has passed the position of the intermediate transfer cleaning device 16 so as to come into contact with the outer peripheral surface of the intermediate transfer belt 8.

ここで、図１を参照して、２次転写ニップの位置に搬送されるシートＰは、装置本体１００の下方に配設された給紙部２６から、給紙ローラ２７やレジストローラ２８（タイミングローラ）等を経由して搬送されるものである。
詳しくは、給紙部２６には、用紙等のシートＰが複数枚重ねて収納されている。そして、給紙ローラ２７が図１の反時計方向に回転駆動されると、一番上のシートＰがレジストローラ２８のローラ間に向けて給送される。 Here, referring to FIG. 1, the sheet P conveyed to the position of the secondary transfer nip is a paper feed roller 27 or a resist roller 28 (timing) from the paper feed unit 26 arranged below the apparatus main body 100. It is transported via a roller) or the like.
Specifically, a plurality of sheets P such as paper are stacked and stored in the paper feed unit 26. Then, when the paper feed roller 27 is rotationally driven in the counterclockwise direction of FIG. 1, the top sheet P is fed between the rollers of the resist roller 28.

レジストローラ２８の位置に搬送されたシートＰは、回転駆動を停止したレジストローラ２８のローラニップの位置で一旦停止する。そして、中間転写ベルト８上のカラー画像にタイミングを合わせて、レジストローラ２８が回転駆動されて、シートＰが２次転写ニップ部に向けて搬送される。こうして、シートＰ上に、所望のカラー画像が転写される。 The sheet P conveyed to the position of the resist roller 28 temporarily stops at the position of the roller nip of the resist roller 28 that has stopped the rotational drive. Then, the resist roller 28 is rotationally driven to match the timing with the color image on the intermediate transfer belt 8, and the sheet P is conveyed toward the secondary transfer nip portion. In this way, the desired color image is transferred onto the sheet P.

その後、２次転写ニップ部の位置でカラー画像が転写されたシートＰは、定着装置２０の位置（定着ニップ）に搬送される。そして、この位置で、定着ベルト２１（定着部材）及び加圧ローラ２２（加圧部材）による熱と圧力とにより、表面に転写されたカラー画像（トナー像）がシートＰ上に定着される（定着工程である。）。
その後、シートＰは、排紙ローラ対によって装置外へと排出される。排紙ローラ対によって装置外に排出されたシートＰは、出力画像として、スタック部（本体カバー１１０）上に順次スタックされる。
こうして、画像形成装置における、一連の画像形成プロセスが完了する。 After that, the sheet P on which the color image is transferred at the position of the secondary transfer nip portion is conveyed to the position (fixing nip) of the fixing device 20. Then, at this position, the color image (toner image) transferred to the surface is fixed on the sheet P by the heat and pressure of the fixing belt 21 (fixing member) and the pressure roller 22 (pressurizing member). It is a fixing process.).
After that, the sheet P is discharged to the outside of the device by the paper ejection roller pair. The sheets P discharged to the outside of the device by the paper ejection roller pair are sequentially stacked on the stack portion (main body cover 110) as an output image.
In this way, a series of image forming processes in the image forming apparatus is completed.

以下、本実施の形態における中間転写ベルト装置１５（画像形成装置１００）において、特徴的な構成・動作について詳述する。
先に図２等を用いて説明したように、ベルト装置としての中間転写ベルト装置１５には、所定の走行方向（図２、図４の矢印方向である。）に走行するベルト部材としての中間転写ベルト８が設置されている。
ここで、図３、図４に示すように、本実施の形態では、中間転写ベルト装置１５（ベルト装置）に、弾性部材３１と保持部材３２とが設けられている。
弾性部材３１は、中間転写ベルト８（ベルト部材）のベルト寄りを規制するために中間転写ベルト８の表面に当接するものである。また、保持部材３２は、弾性部材３１を保持するものである。 Hereinafter, the characteristic configuration and operation of the intermediate transfer belt device 15 (image forming device 100) according to the present embodiment will be described in detail.
As described above with reference to FIG. 2 and the like, the intermediate transfer belt device 15 as a belt device has an intermediate as a belt member traveling in a predetermined traveling direction (in the direction of arrows in FIGS. 2 and 4). A transfer belt 8 is installed.
Here, as shown in FIGS. 3 and 4, in the present embodiment, the intermediate transfer belt device 15 (belt device) is provided with the elastic member 31 and the holding member 32.
The elastic member 31 comes into contact with the surface of the intermediate transfer belt 8 in order to regulate the belt deviation of the intermediate transfer belt 8 (belt member). Further, the holding member 32 holds the elastic member 31.

詳しくは、弾性部材３１は、フェルト、スポンジ、ゴムなどの弾性材料で形成された略直方体の部材であって、樹脂材料などからなる保持部材３２に接着剤を介して接着されている。図３に示すように、弾性部材３１は、従動ローラ１１に張架された中間転写ベルト８の外周面に、画像領域の領域外で圧接するように設置されている。すなわち、弾性部材３１は、従動ローラ１１との間に中間転写ベルト８を挟むように、中間転写ベルト８に圧接している。
一方、保持部材３２は、剛性を有する樹脂材料や金属材料で形成されていて、中間転写ベルト８の走行を妨げないように中間転写ベルト装置１５の筐体に固定して設置されている。 Specifically, the elastic member 31 is a substantially rectangular parallelepiped member made of an elastic material such as felt, sponge, or rubber, and is adhered to a holding member 32 made of a resin material or the like via an adhesive. As shown in FIG. 3, the elastic member 31 is installed so as to be in pressure contact with the outer peripheral surface of the intermediate transfer belt 8 stretched on the driven roller 11 outside the region of the image region. That is, the elastic member 31 is in pressure contact with the intermediate transfer belt 8 so as to sandwich the intermediate transfer belt 8 with the driven roller 11.
On the other hand, the holding member 32 is made of a rigid resin material or a metal material, and is fixedly installed in the housing of the intermediate transfer belt device 15 so as not to hinder the running of the intermediate transfer belt 8.

このような構成により、弾性部材３１は、所定の走行方向に走行する中間転写ベルト８に摺接しながら、中間転写ベルト８を従動ローラ１１に向けて押圧することになる。これにより、中間転写ベルト８を張架・支持するローラ部材の軸心の傾きなどによって、中間転写ベルト８が幅方向（図２の紙面垂直方向であって、図３の左右方向である。）に移動（ベルト寄り）しそうになっても、弾性部材３１によって中間転写ベルト８が従動ローラ１１に押し付けられているため、そのようなベルト寄りの発生を軽減することができる。 With such a configuration, the elastic member 31 presses the intermediate transfer belt 8 toward the driven roller 11 while sliding contact with the intermediate transfer belt 8 traveling in a predetermined traveling direction. As a result, the intermediate transfer belt 8 is in the width direction (the direction perpendicular to the paper surface in FIG. 2 and the left-right direction in FIG. 3) due to the inclination of the axial center of the roller member that stretches and supports the intermediate transfer belt 8. Since the intermediate transfer belt 8 is pressed against the driven roller 11 by the elastic member 31, even if it is about to move (close to the belt), it is possible to reduce the occurrence of such movement toward the belt.

なお、本実施の形態では、中間転写ベルト８のベルト寄りをさらに軽減するために、従動ローラ１１の幅方向両端部に、それぞれ、従動ローラ１１のローラ部よりも大きな外径を有するフランジ１１ａが形成されている。
また、本実施の形態において、中間転写ベルト８に対する弾性部材３１の摺動抵抗を減ずるために、少なくとも弾性部材３１の接触面３１ａ（中間転写ベルト８に接触する面である。）を低摩擦材料で形成することが好ましい。 In the present embodiment, in order to further reduce the belt deviation of the intermediate transfer belt 8, flanges 11a having an outer diameter larger than that of the roller portion of the driven roller 11 are provided at both ends of the driven roller 11 in the width direction. It is formed.
Further, in the present embodiment, in order to reduce the sliding resistance of the elastic member 31 with respect to the intermediate transfer belt 8, at least the contact surface 31a of the elastic member 31 (the surface that contacts the intermediate transfer belt 8) is made of a low friction material. It is preferable to form with.

ここで、本実施の形態において、弾性部材３１は、図４に示すように、走行方向の上流側端部（中間転写ベルト８の走行方向に対して上流側に位置する端部である。）が中間転写ベルト８の表面に当接しないように、面取り部３１ｂが形成されている。詳しくは、面取り部３１ｂは、図４に示すように、幅方向にわたってＣ面状に形成されていて、弾性部材３１の上流側端部が中間転写ベルト８に接触しないように逃げ部（非接触部）として機能する。そして、弾性部材３１は、面取り部３１ｂが形成された上流側端部を除く範囲が接触面３１ａとして中間転写ベルト８に接触するように構成されている。 Here, in the present embodiment, as shown in FIG. 4, the elastic member 31 is an upstream end portion in the traveling direction (an end portion located on the upstream side with respect to the traveling direction of the intermediate transfer belt 8). The chamfered portion 31b is formed so that the surface of the intermediate transfer belt 8 does not come into contact with the surface of the intermediate transfer belt 8. Specifically, as shown in FIG. 4, the chamfered portion 31b is formed in a C-plane shape over the width direction, and is a relief portion (non-contact) so that the upstream end portion of the elastic member 31 does not come into contact with the intermediate transfer belt 8. It functions as a part). The elastic member 31 is configured so that the range excluding the upstream end on which the chamfered portion 31b is formed comes into contact with the intermediate transfer belt 8 as the contact surface 31a.

また、本実施の形態において、弾性部材３１は、中間転写ベルト８に接触する接触面３１ａと面取り部３１ｂとに対向する対向面（接触面３１ａに対して平行な面であって、接着面３１ｃである。）が、保持部材３２の第１対向面３２ａ１に接着されている。
なお、本実施の形態（又は、後述する変形例）では、弾性部材３１を保持部材３２に対して接着剤を介して接着したが、弾性部材３１を保持部材３２に対して両面テープを介して貼着しても良い。 Further, in the present embodiment, the elastic member 31 is a facing surface (a surface parallel to the contact surface 31a and an adhesive surface 31c) facing the contact surface 31a in contact with the intermediate transfer belt 8 and the chamfered portion 31b. Is adhered to the first facing surface 32a1 of the holding member 32.
In the present embodiment (or a modification described later), the elastic member 31 is adhered to the holding member 32 via an adhesive, but the elastic member 31 is attached to the holding member 32 via double-sided tape. You may stick it.

このように、本実施の形態では、弾性部材３１の上流側端部に面取り部３１ｂを形成しているため、中間転写ベルト８に摺接することによって弾性部材３１が変形して、弾性部材３１の上流側端部が中間転写ベルト８に巻き込まれてしまう不具合が生じにくくなる。
すなわち、図５に比較例として示す弾性部材１３１のように、上流側端部に面取り部が形成されずに、上流側から下流側に至る全範囲が中間転写ベルト８に接触するように形成されている場合には、中間転写ベルト８に摺接することによって弾性部材１３１が変形して、弾性部材１３１の上流側端部（図５にて破線で囲んだ角部である。）が中間転写ベルト８に巻き込まれてしまう不具合が生じやすい。そして、そのように弾性部材１３１の上流側端部が中間転写ベルト８に巻き込まれてしまうと、弾性部材１３１が保持部材３２から剥がれて破損してしまったり、剥がれた弾性部材１３１によって中間転写ベルト８が破損してしまったりすることになる。
これに対して、本実施の形態では、中間転写ベルト８に摺接することによって弾性部材３１が変形してしまったとしても、その上流側端部には面取り部３１ｂが形成されているため、その部分が中間転写ベルト８に巻き込まれてしまうことはない。したがって、弾性部材１３１が保持部材３２から剥がれて破損してしまう不具合や、剥がれた弾性部材１３１によって中間転写ベルト８が破損してしまう不具合も生じにくくなる。 As described above, in the present embodiment, since the chamfered portion 31b is formed at the upstream end portion of the elastic member 31, the elastic member 31 is deformed by sliding contact with the intermediate transfer belt 8 to form the elastic member 31. The problem that the upstream end is caught in the intermediate transfer belt 8 is less likely to occur.
That is, unlike the elastic member 131 shown as a comparative example in FIG. 5, the chamfered portion is not formed at the upstream end portion, and the entire range from the upstream side to the downstream side is formed so as to contact the intermediate transfer belt 8. In this case, the elastic member 131 is deformed by sliding contact with the intermediate transfer belt 8, and the upstream end portion (the corner portion surrounded by the broken line in FIG. 5) of the elastic member 131 is the intermediate transfer belt. The problem of getting caught in 8 is likely to occur. If the upstream end of the elastic member 131 is caught in the intermediate transfer belt 8 in this way, the elastic member 131 may be peeled off from the holding member 32 and damaged, or the peeled elastic member 131 may cause the intermediate transfer belt to be damaged. 8 will be damaged.
On the other hand, in the present embodiment, even if the elastic member 31 is deformed by sliding contact with the intermediate transfer belt 8, the chamfered portion 31b is formed at the upstream end portion thereof, so that the elastic member 31 is deformed. The portion is not caught in the intermediate transfer belt 8. Therefore, the problem that the elastic member 131 is peeled off from the holding member 32 and is damaged, and the problem that the intermediate transfer belt 8 is damaged by the peeled elastic member 131 are less likely to occur.

ここで、本実施の形態において、保持部材３２は、図４に示すように、下流側が上流側（矢印で示す中間転写ベルト８の走行方向に対する上流・下流である。）に比べて中間転写ベルト８との対向距離が短くなるように段差部３２ｄが形成されている。すなわち、保持部材３２は、上流側の第１対向面３２ａ１に比べて、下流側の第２対向面３２ａ２が中間転写ベルト８に近い位置に形成されていて、第１対向面３２ａ１と第２対向面３２ａ２との境界部が段差部３２ｄとなっている。
そして、弾性部材３１は、走行方向の下流側端面（図４の右方の端面である。）が、保持部材３２の段差部３２ｄに突き当たるように設置されている。
このように構成することにより、中間転写ベルト８との摺接によって中間転写ベルト８の走行方向に沿うように変形する力が弾性部材３１に作用しても、その力の一部を段差部３２ｄで受けることになるため、弾性部材３１の変形を軽減することができる。したがって、先に説明した弾性部材３１が中間転写ベルト８に巻き込まれるのを防止する効果が、さらに発揮されることになる。 Here, in the present embodiment, as shown in FIG. 4, the holding member 32 has an intermediate transfer belt on the downstream side as compared with the upstream side (upstream / downstream with respect to the traveling direction of the intermediate transfer belt 8 indicated by the arrow). The step portion 32d is formed so that the facing distance from 8 is shortened. That is, in the holding member 32, the second facing surface 32a2 on the downstream side is formed at a position closer to the intermediate transfer belt 8 than the first facing surface 32a1 on the upstream side, and the first facing surface 32a1 and the second facing surface 32a1 face each other. The boundary portion with the surface 32a2 is a stepped portion 32d.
The elastic member 31 is installed so that the downstream end surface in the traveling direction (the right end surface in FIG. 4) abuts on the stepped portion 32d of the holding member 32.
With this configuration, even if a force that deforms along the traveling direction of the intermediate transfer belt 8 due to sliding contact with the intermediate transfer belt 8 acts on the elastic member 31, a part of the force acts on the step portion 32d. Therefore, the deformation of the elastic member 31 can be reduced. Therefore, the effect of preventing the elastic member 31 described above from being caught in the intermediate transfer belt 8 is further exerted.

＜変形例＞
図６（Ａ）〜（Ｃ）は、それぞれ、変形例としての中間転写ベルト装置１５の要部を示す概略拡大図であって、いずれも本実施の形態における図４に対応する図である。
図６（Ａ）に示す第１の変形例では、弾性部材３１の面取り部３１ｂが、Ｒ面状（曲面状）に形成されている。このように構成した場合には、中間転写ベルト８との摺接によって弾性部材３１が変形して面取り部３１ｂに応力がかかったときに、その応力が一か所に集中することなく分散されやすくなる。そのため、弾性部材３１が保持部材３２からさらに剥がれにくくなる。 <Modification example>
6 (A) to 6 (C) are schematic enlarged views showing a main part of the intermediate transfer belt device 15 as a modified example, and all of them are views corresponding to FIG. 4 in the present embodiment.
In the first modification shown in FIG. 6A, the chamfered portion 31b of the elastic member 31 is formed in an R-plane shape (curved surface shape). In this configuration, when the elastic member 31 is deformed by the sliding contact with the intermediate transfer belt 8 and stress is applied to the chamfered portion 31b, the stress is easily dispersed without being concentrated in one place. Become. Therefore, the elastic member 31 is more difficult to peel off from the holding member 32.

図６（Ｂ）に示す第２の変形例では、弾性部材３１は、保持部材３２において、中間転写ベルト８に対向する面（第１対向面３２ａ１である。）に加えて、走行方向の上流側端面３２ｂにも、接着（又は、貼着）されている。すなわち、弾性部材３１は、略Ｌ字状に形成されて、その第１接着面３１ｃが保持部材３２の第１対向面３２ａ１に接着され、その第２接着面３１ｄが保持部材３２の上流側端面３２ｂに接着されている。
このように構成した場合には、保持部材３２に対する弾性部材３１の接着面積が広くなるとともに、弾性部材３１の上流側端部を跨ぐように保持部材３２に対して弾性部材３１が接着されることになるため、弾性部材３１が保持部材３２からさらに剥がれにくくなる。 In the second modification shown in FIG. 6B, the elastic member 31 is the holding member 32 upstream in the traveling direction in addition to the surface facing the intermediate transfer belt 8 (the first facing surface 32a1). It is also adhered (or affixed) to the side end surface 32b. That is, the elastic member 31 is formed in a substantially L shape, the first adhesive surface 31c is adhered to the first facing surface 32a1 of the holding member 32, and the second adhesive surface 31d is the upstream end surface of the holding member 32. It is adhered to 32b.
In this configuration, the area of adhesion of the elastic member 31 to the holding member 32 is widened, and the elastic member 31 is adhered to the holding member 32 so as to straddle the upstream end of the elastic member 31. Therefore, the elastic member 31 is less likely to be peeled off from the holding member 32.

図６（Ｃ）に示す第３の変形例では、弾性部材３１は、第２の変形例のものに対して、保持部材３２において第１対向面３２ａ１（対向する面）に対して反対側の面であって上流側端面３２ｂに繋がる面（上面３２ｃである。）にも接着（又は、貼着）されている。すなわち、弾性部材３１は、略Ｕ字状（又は、略「コ」の字状）に形成されて、その第１接着面３１ｃが保持部材３２の第１対向面３２ａ１に接着され、その第２接着面３１ｄが保持部材３２の上流側端面３２ｂに接着され、その第３接着面３１ｅが保持部材３２の上面３２ｃに接着されている。
このように構成した場合には、保持部材３２に対する弾性部材３１の接着面積がさらに広くなるとともに、弾性部材３１の上流側端部を跨ぐように保持部材３２に対して弾性部材３１がさらに強固に接着されることになるため、弾性部材３１が保持部材３２からさらに剥がれにくくなる。
なお、第２の変形例や第３の変形例において、弾性部材３１は、厚さが一定の１枚のシート状のものを、保持部材３２を覆うように接着（又は、貼着）することで構成することもできる。その場合、保持部材３２の角部（第１対向面３２ａ１と上流側端面３２ｂとが交差する部分である。）にならうように、弾性部材３１にＲ面状の面取り部３１ｂが形成されることになるため、弾性部材３１の製造費が低廉化されることになる。 In the third modification shown in FIG. 6C, the elastic member 31 is on the opposite side of the holding member 32 from the first facing surface 32a1 (opposing surface) with respect to that of the second modification. It is also adhered (or attached) to a surface (the upper surface 32c) that is connected to the upstream end surface 32b. That is, the elastic member 31 is formed in a substantially U shape (or a substantially "U" shape), and its first adhesive surface 31c is adhered to the first facing surface 32a1 of the holding member 32, and the second adhesive surface 31c thereof is adhered to the first facing surface 32a1. The adhesive surface 31d is adhered to the upstream end surface 32b of the holding member 32, and the third adhesive surface 31e is adhered to the upper surface 32c of the holding member 32.
In this configuration, the adhesive area of the elastic member 31 to the holding member 32 is further increased, and the elastic member 31 is further strengthened to the holding member 32 so as to straddle the upstream end portion of the elastic member 31. Since they are adhered to each other, the elastic member 31 is more difficult to peel off from the holding member 32.
In the second modification and the third modification, the elastic member 31 is formed by adhering (or sticking) one sheet having a constant thickness so as to cover the holding member 32. It can also be configured with. In that case, an R-plane chamfered portion 31b is formed on the elastic member 31 so as to follow the corner portion of the holding member 32 (the portion where the first facing surface 32a1 and the upstream end surface 32b intersect). Therefore, the manufacturing cost of the elastic member 31 is reduced.

以下、図７を用いて、本発明の効果を確認するためにおこなった実験と、その実験結果と、について説明する。
実験は、５つ（比較例、実施例１〜４）の形状の異なる弾性部材を用いたときの、実機における弾性部材（又は、中間転写ベルト）の破損の有無を、通紙枚数５０００枚ごとに目視で確認したものである。弾性部材は、スポンジ材料で形成されたものを用いて、引張強度が０．７７Ｍｐａであって引裂強度が２．４Ｎ／ｍｍにて接着したものを用いている。また、図７において、「比較例」に用いた弾性部材は図５に示したものであって、「実施例１」に用いた弾性部材は図４に示したものであって、「実施例２」に用いた弾性部材は図６（Ａ）に示したものであって、「実施例３」に用いた弾性部材は図６（Ｂ）に示したものであって、「実施例４」に用いた弾性部材は図６（Ｃ）に示したものである。
図７において、「○」は弾性部材（又は、中間転写ベルト）の破損が生じていない状態であって、「×」は弾性部材（又は、中間転写ベルト）の破損が生じている状態である。
図７に示す実験結果からも、弾性部材３１の上流側端部に面取り部３１ｂを形成することにより、弾性部材３１（又は、中間転写ベルト８）の破損が生じにくくなることがわかる。また、面取り部３１ｂの形状は、Ｃ面状であるよりもＲ面状である方が、弾性部材３１（又は、中間転写ベルト８）の破損が生じにくくなることがわかる。さらに、弾性部材３１の接着面は、第１接着面３１ｃのみであるよりも、第２接着面３１ｄ、第３接着面３１ｅと接着面が増加するほど、弾性部材３１（又は、中間転写ベルト８）の破損が生じにくくなることがわかる。 Hereinafter, with reference to FIG. 7, an experiment conducted for confirming the effect of the present invention and the result of the experiment will be described.
In the experiment, when five elastic members having different shapes (Comparative Examples, Examples 1 to 4) were used, the presence or absence of damage to the elastic members (or intermediate transfer belts) in the actual machine was checked every 5000 sheets of paper. It was confirmed visually. As the elastic member, a member made of a sponge material is used, and a member having a tensile strength of 0.77 Mpa and a tear strength of 2.4 N / mm is used. Further, in FIG. 7, the elastic member used in "Comparative Example" is the one shown in FIG. 5, and the elastic member used in "Example 1" is the one shown in FIG. The elastic member used in "2" is shown in FIG. 6 (A), and the elastic member used in "Example 3" is shown in FIG. 6 (B), and is shown in "Example 4". The elastic member used in is shown in FIG. 6 (C).
In FIG. 7, “◯” indicates that the elastic member (or intermediate transfer belt) has not been damaged, and “x” indicates that the elastic member (or intermediate transfer belt) has not been damaged. ..
From the experimental results shown in FIG. 7, it can be seen that the elastic member 31 (or the intermediate transfer belt 8) is less likely to be damaged by forming the chamfered portion 31b at the upstream end portion of the elastic member 31. Further, it can be seen that when the chamfered portion 31b has an R-plane shape rather than a C-plane shape, the elastic member 31 (or the intermediate transfer belt 8) is less likely to be damaged. Further, as the adhesive surface of the elastic member 31 increases as the number of the adhesive surfaces with the second adhesive surface 31d and the third adhesive surface 31e increases, the elastic member 31 (or the intermediate transfer belt 8) has more adhesive surfaces than only the first adhesive surface 31c. ) Is less likely to be damaged.

以上説明したように、本実施の形態における中間転写ベルト装置１５（ベルト装置）は、中間転写ベルト８（ベルト部材）のベルト寄りを規制するために中間転写ベルト８の表面に当接する弾性部材３１が、保持部材３２に保持されている。そして、弾性部材３１は、その上流側端部が中間転写ベルト８の表面に当接しないように、面取り部３１ｂが形成されている。
これにより、中間転写ベルト８に摺接する弾性部材３１が中間転写ベルト８に巻き込まれてしまう不具合を生じにくくすることができる。 As described above, the intermediate transfer belt device 15 (belt device) in the present embodiment is an elastic member 31 that comes into contact with the surface of the intermediate transfer belt 8 in order to regulate the belt deviation of the intermediate transfer belt 8 (belt member). Is held by the holding member 32. The elastic member 31 is formed with a chamfered portion 31b so that its upstream end does not come into contact with the surface of the intermediate transfer belt 8.
As a result, it is possible to prevent the problem that the elastic member 31 that is in sliding contact with the intermediate transfer belt 8 is caught in the intermediate transfer belt 8.

なお、本実施の形態では、ベルト部材としての中間転写ベルト８が設置されたベルト装置（中間転写ベルト装置１５）に対して本発明を適用したが、本発明の適用はこれに限定されることはない。例えば、転写搬送ベルト、感光体ベルト、定着ベルト等のベルト部材が設けられたベルト装置に対しても、ベルト部材のベルト寄りを防止するための弾性部材が設置されたものであれば、本発明を適用することができる。
そして、そのような場合にも、本実施の形態のものと同様の効果を得ることができる。 In the present embodiment, the present invention is applied to a belt device (intermediate transfer belt device 15) in which the intermediate transfer belt 8 as a belt member is installed, but the application of the present invention is limited to this. There is no. For example, even in a belt device provided with a belt member such as a transfer transfer belt, a photoconductor belt, and a fixing belt, the present invention is provided as long as an elastic member for preventing the belt member from approaching the belt is installed. Can be applied.
Then, even in such a case, the same effect as that of the present embodiment can be obtained.

なお、本発明が本実施の形態に限定されず、本発明の技術思想の範囲内において、本実施の形態の中で示唆した以外にも、本実施の形態は適宜変更され得ることは明らかである。また、前記構成部材の数、位置、形状等は本実施の形態に限定されず、本発明を実施する上で好適な数、位置、形状等にすることができる。 It is clear that the present invention is not limited to the present embodiment, and the present embodiment may be appropriately modified in addition to the suggestions in the present embodiment within the scope of the technical idea of the present invention. is there. Further, the number, position, shape, etc. of the constituent members are not limited to the present embodiment, and can be a suitable number, position, shape, etc. for carrying out the present invention.

なお、本願明細書等において、弾性部材に形成される「面取り部」は、その製造方法を特定するものではないものと定義する。したがって、「面取り部」は、２次的な加工としておこなわれる面取り加工によって形成されるものに限らず、成型加工など種々の製造方法で形成され得るものである。 In the specification of the present application and the like, the "chamfered portion" formed on the elastic member is defined as not specifying the manufacturing method thereof. Therefore, the "chamfered portion" is not limited to the one formed by the chamfering process performed as a secondary process, but can be formed by various manufacturing methods such as a molding process.

８中間転写ベルト（ベルト部材）、
１０駆動ローラ（ローラ部材）、
１１従動ローラ（ローラ部材）、
１５中間転写ベルト装置（ベルト装置）、
３１弾性部材（押え部材）、
３１ａ接触面、
３１ｂ面取り部（逃げ部、非接触部）、
３１ｃ接着面（対向面）、
３１ｄ第２接着面、３１ｅ第３接着面、
３２保持部材（ホルダ）、
３２ａ１第１対向面、３２ａ２第２対向面（被接着面）、
３２ｂ上流側端面、３２ｃ上面、
３２ｄ段差、
１００画像形成装置（画像形成装置本体）、Ｐシート（記録媒体）。 8 Intermediate transfer belt (belt member),
10 Drive roller (roller member),
11 Driven roller (roller member),
15 Intermediate transfer belt device (belt device),
31 Elastic member (pressing member),
31a contact surface,
31b Chamfered part (relief part, non-contact part),
31c Adhesive surface (opposing surface),
31d 2nd adhesive surface, 31e 3rd adhesive surface,
32 Holding member (holder),
32a1 first facing surface, 32a2 second facing surface (bonded surface),
32b upstream end face, 32c top surface,
32d step,
100 Image forming apparatus (image forming apparatus main body), P sheet (recording medium).

特許第５０１７６８４号公報Japanese Patent No. 5017684

Claims

A belt member that travels in a predetermined traveling direction and
An elastic member that comes into contact with the surface of the belt member in order to regulate the belt deviation of the belt member, and
A holding member that holds the elastic member and
With
The elastic member is a belt device characterized in that a C-plane chamfered portion is formed so that the upstream end portion in the traveling direction does not abut on the surface of the belt member.

The belt device according to claim 1, wherein the elastic member has a contact surface in contact with the belt member and an opposing surface facing the chamfered portion, which are attached or adhered to the holding member.

The belt according to claim 1 or 2, wherein the elastic member is attached or adhered to the upstream end surface in the traveling direction in addition to the surface of the holding member facing the belt member. apparatus.

The belt according to claim 3, wherein the elastic member is attached or adhered to a surface of the holding member that is opposite to the facing surface and is connected to the upstream end surface. apparatus.

The holding member is formed with a step portion so that the downstream side in the traveling direction has a shorter facing distance from the belt member than the upstream side.
The belt device according to any one of claims 1 to 4, wherein the elastic member is installed so that the downstream end surface in the traveling direction abuts on the step portion of the holding member.

A belt member that travels in a predetermined traveling direction and
An elastic member that comes into contact with the surface of the belt member in order to regulate the belt deviation of the belt member, and
A holding member that holds the elastic member and
With
The elastic member has a chamfered portion formed so that the upstream end portion in the traveling direction does not come into contact with the surface of the belt member.
The elastic member is a belt device characterized in that a contact surface in contact with the belt member and an opposing surface facing the chamfered portion are attached or adhered to the holding member.

A belt member that travels in a predetermined traveling direction and
An elastic member that comes into contact with the surface of the belt member in order to regulate the belt deviation of the belt member, and
A holding member that holds the elastic member and
With
The elastic member has a chamfered portion formed so that the upstream end portion in the traveling direction does not come into contact with the surface of the belt member.
The belt device is characterized in that the elastic member is attached or adhered to the upstream end surface in the traveling direction in addition to the surface of the holding member facing the belt member.

The belt according to claim 7, wherein the elastic member is attached or adhered to a surface of the holding member that is opposite to the facing surface and is connected to the upstream end surface. apparatus.

A belt member that travels in a predetermined traveling direction and
An elastic member that comes into contact with the surface of the belt member in order to regulate the belt deviation of the belt member, and
A holding member that holds the elastic member and
With
The elastic member has a chamfered portion formed so that the upstream end portion in the traveling direction does not come into contact with the surface of the belt member.
The holding member is formed with a step portion so that the downstream side in the traveling direction has a shorter facing distance from the belt member than the upstream side.
The elastic member is a belt device characterized in that the downstream end surface in the traveling direction is installed so as to abut against the stepped portion of the holding member.

An image forming apparatus comprising the belt apparatus according to any one of claims 1 to 9.