JP6415664B1

JP6415664B1 - Image forming apparatus

Info

Publication number: JP6415664B1
Application number: JP2017186696A
Authority: JP
Inventors: 慎也北郷
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2017-09-27
Filing date: 2017-09-27
Publication date: 2018-10-31
Anticipated expiration: 2037-09-27
Also published as: JP2019061138A

Abstract

【課題】ベルトユニットに回動可能な把手部を取り付ける構成において、ベルトユニットの大型化を抑制しながら把手部とベルトの距離を確保する。更に、少ない部品点数で把手部を取り付け可能なベルトユニットを提供する。【解決手段】把手部を回動可能に支持する軸は、大径部と小径部を備え、把手部に設けられた貫通穴は、小径部が嵌合する第一穴部と、第一穴部と軸線方向直交方向で連通され、大径部が挿入可能な第二穴部と、を備える。第一穴部と第二穴部の間に突起部が形成され、突起部が形成する隙間は、小径部の外径よりも狭い。軸は、突起部が形成する隙間よりも狭いＤカット部を備え、Ｄカット部が隙間と対向するときに軸が第一穴部と第二穴部の間を移動可能に構成される。軸が装着位置にあるときは、軸部は突起部により第一穴部と第二穴部の間の移動が規制される。【選択図】図９PROBLEM TO BE SOLVED: To secure a distance between a handle portion and a belt while suppressing an increase in size of the belt unit in a configuration in which a rotatable handle portion is attached to the belt unit. Furthermore, a belt unit capable of attaching a handle with a small number of parts is provided. A shaft that rotatably supports a handle includes a large-diameter portion and a small-diameter portion, and a through hole provided in the handle portion includes a first hole portion into which the small-diameter portion is fitted, and a first hole. And a second hole portion which is communicated with the portion in the direction orthogonal to the axial direction and into which the large diameter portion can be inserted. A protrusion is formed between the first hole and the second hole, and the gap formed by the protrusion is narrower than the outer diameter of the small diameter portion. The shaft includes a D-cut portion that is narrower than the gap formed by the protrusion, and the shaft is configured to be movable between the first hole portion and the second hole portion when the D-cut portion faces the gap. When the shaft is in the mounting position, the movement of the shaft portion between the first hole portion and the second hole portion is restricted by the protruding portion. [Selection] Figure 9

Description

本発明は、電子写真方式や静電記録方式を用いた複写機、プリンタ、ファクシミリ装置などの画像形成装置に関するものである。 The present invention relates to an image forming apparatus such as a copying machine, a printer, or a facsimile apparatus using an electrophotographic system or an electrostatic recording system.

プリンタや複写機等の画像形成装置には小型・高機能が求められており、それに伴い、装置内部の各ユニットには省スペースな設計が求められる。一方で、安定した画像をユーザーに提供し続けるために、装置内部の各ユニットの定期的なメンテナンス・交換を行っている。そのため、操作性の観点からユニットには把手部材が備えられ、ユーザーやサービスマンは把手部材を支持してユニットの持ち運びを行うため作業性が良い。 Image forming apparatuses such as printers and copiers are required to have a small size and high functionality. Accordingly, each unit in the apparatus is required to have a space-saving design. On the other hand, in order to continue providing a stable image to the user, each unit in the apparatus is regularly maintained and replaced. For this reason, the unit is provided with a handle member from the viewpoint of operability, and the user and the service person support the handle member and carry the unit, so that the workability is good.

特開２０１７−４５０１４号公報Japanese Unexamined Patent Publication No. 2017-45014

従来、例えば、特許文献１では、軸部材に、ベルトユニットを把手するための把手部材を取り付ける構成が提案されている。 Conventionally, for example, Patent Document 1 proposes a configuration in which a handle member for gripping a belt unit is attached to a shaft member.

軸部材に把手部材を組付ける構成として、把手部材に備えられた円筒穴に軸部材を通過させるものが考えられる。しかし、ユニットの小型化のために、周回搬送されるベルト部材と上述した軸部材が近接して配置される構成では、軸部材に備えられた把手部材がベルト部材と接触する懸念がある。把手部材とベルト部材が接触するとベルト部材に傷を付け、ベルト部材の傷が付いた個所において転写されるトナー像が乱れ画像不良を発生させる。そこで、把手部材とベルト部材の距離をできるだけ離間させることが望まれる。把手部材とベルト部材の距離を小さくするには、把手部材の肉厚を最低限確保した上で、軸部材の軸径を極力小さくすればよい。しかしながら、軸部材全体を小径化してしまうと、軸部材の強度が低下してしまい、撓んでしまう。そこで、把手部材が取り付けられる領域のみを小径化し、把手部材を小径部分に取り付ける構成が考えられる。このように、軸径が異なる軸部材を把手部材に挿入させる構成を採用した場合、把手部材に軸部材を通過させる貫通穴として、以下のような形状が考えられる。まず、軸部材の大径部を挿入させるための大径部用の孔部を設ける。そして、軸部材の小径部が把手部材の貫通穴に挿入された後に、軸部材の小径部と嵌合する小径部用の穴部を設けることが考えられる。このとき、軸部材の小径部が小径部用の穴部から外れないように軸部材を把手部材に固定する固定部材が必要となる。このため、部品点数が増加してしまう問題があった。 As a configuration for assembling the handle member to the shaft member, a configuration in which the shaft member is passed through a cylindrical hole provided in the handle member is conceivable. However, in order to reduce the size of the unit, the grip member provided on the shaft member may come into contact with the belt member in the configuration in which the belt member that is circulated and the shaft member described above are arranged close to each other. When the handle member and the belt member come into contact with each other, the belt member is damaged, and the toner image transferred at the damaged portion of the belt member is disturbed to cause an image defect. Therefore, it is desirable to keep the distance between the handle member and the belt member as far as possible. In order to reduce the distance between the handle member and the belt member, it is only necessary to minimize the shaft diameter of the shaft member while ensuring the minimum thickness of the handle member. However, if the diameter of the entire shaft member is reduced, the strength of the shaft member is reduced and the shaft member is bent. Therefore, a configuration is conceivable in which only the region to which the handle member is attached is reduced in diameter, and the handle member is attached to the small diameter portion. Thus, when the structure which inserts the shaft member from which a shaft diameter differs in a handle member is employ | adopted, the following shapes can be considered as a through-hole which lets a shaft member pass a handle member. First, a hole for a large diameter portion for inserting the large diameter portion of the shaft member is provided. And after the small diameter part of a shaft member is inserted in the through-hole of a handle member, it is possible to provide the hole part for small diameter parts fitted with the small diameter part of a shaft member. At this time, a fixing member for fixing the shaft member to the handle member is necessary so that the small diameter portion of the shaft member does not come out of the hole for the small diameter portion. For this reason, there was a problem that the number of parts will increase.

そこで、本発明の目的は、ベルトユニットに設けられた軸部材に対して把手部材を取り付ける画像形成装置において、大型化を抑制しながら少ない部品点数で把手部材を取り付け可能な画像形成装置を提供することにある。 SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming apparatus in which a handle member can be attached with a small number of parts while suppressing an increase in size in an image forming apparatus in which a handle member is attached to a shaft member provided in a belt unit. There is.

本発明の画像形成装置は、画像を担持する像担持体と、装置本体に着脱可能に設けられ、前記像担持体が担持するトナー像が転写されるベルトを備えたベルトユニットと、前記ベルトユニットに回動可能に設けられ、前記ベルトユニットを装置本体から取り出す際に前記ベルトユニットを把手するための把手部と、前記ベルトユニットに設けられ、前記把手部に設けられた貫通穴に挿入されて前記把手部を回動可能に支持する軸と、を備えた画像形成装置であって、前記軸は、第一の軸部と、前記第一の軸部よりも太い第二の軸部と、を備え、前記貫通穴は、前記第一の軸部が嵌合可能な第一穴部と、前記軸の軸線方向と直交する方向に関して前記第一穴部とは異なる位置に設けられ、前記第二の軸部が挿入可能な第二穴部と、前記第一穴部と前記第二穴部を連通させる連通部と、を備え、前記把手部が前記ベルトユニットに装着されているときに前記第一の軸部と対向する位置に設けられ、前記連通部の間隙が前記第一の軸部の外径よりも狭くなるように前記貫通穴の内面から突出する突起部を備え、前記軸は、前記軸の軸線方向と直交する所定方向の厚みが前記第一の軸部よりも小さく、前記軸の軸線方向の長さが前記突起部よりも長い第三の軸部を備え、前記第三の軸部が前記突起部と対向する位置にあるとき、前記軸が前記連通部を通過可能に構成されている、ことを特徴とする。 An image forming apparatus according to the present invention includes an image carrier that carries an image, a belt unit that is detachably provided on the apparatus main body and onto which a toner image carried by the image carrier is transferred, and the belt unit. And a handle part for gripping the belt unit when the belt unit is taken out from the main body of the apparatus, and a through hole provided in the handle part. An image forming apparatus comprising: a shaft that rotatably supports the handle portion, wherein the shaft includes a first shaft portion and a second shaft portion that is thicker than the first shaft portion; The through hole is provided at a position different from the first hole portion with respect to a first hole portion into which the first shaft portion can be fitted and a direction orthogonal to the axial direction of the shaft, A second hole part into which the second shaft part can be inserted, and the first hole part A communication portion for communicating the second hole portion, and the handle portion is provided at a position facing the first shaft portion when the handle unit is attached to the belt unit, and the gap of the communication portion is the A projection that protrudes from the inner surface of the through-hole so as to be narrower than the outer diameter of the first shaft, and the shaft has a thickness in a predetermined direction perpendicular to the axial direction of the shaft; A third shaft portion that is smaller than the protrusion portion and has a length in the axial direction of the shaft that is longer than the protrusion portion, and the shaft is in communication with the communication portion when the third shaft portion is in a position facing the protrusion portion. It is configured to be able to pass through the section.

本発明によれば、ベルトユニットに設けられた軸部材に対して把手部材を取り付ける画像形成装置において、大型化を抑制しながら少ない部品点数で把手部材を取り付け可能な画像形成装置を提供することができる。 According to the present invention, in the image forming apparatus in which the handle member is attached to the shaft member provided in the belt unit, it is possible to provide an image forming apparatus in which the handle member can be attached with a small number of parts while suppressing an increase in size. it can.

画像形成装置の概略断面図Schematic sectional view of the image forming apparatus 画像形成時における中間転写ベルトユニットの概略断面図Schematic sectional view of the intermediate transfer belt unit during image formation 第一の状態における中間転写ベルトユニットの概略断面図Schematic sectional view of the intermediate transfer belt unit in the first state 第二の状態における中間転写ベルトユニットの概略断面図Schematic sectional view of the intermediate transfer belt unit in the second state 中間転写ベルトユニットを持ち運ぶ際の状態の概略斜視図Schematic perspective view of the state when carrying the intermediate transfer belt unit 中間転写ベルトユニットの把手部材周辺の概略斜視図Schematic perspective view around the grip member of the intermediate transfer belt unit 把手部材の概略斜視図Schematic perspective view of the handle member Ｄカット部周辺部の概略断面図Schematic cross-sectional view around the D-cut part 軸部材と把手部材近傍の概略斜視図および概略断面図Schematic perspective view and schematic sectional view in the vicinity of the shaft member and the handle member 把手部材組み付け時の概略斜視図および概略断面図Schematic perspective view and schematic sectional view when assembling the handle member 把手部材（実施例２）の概略斜視図Schematic perspective view of handle member (Example 2) 把手部材（実施例２）組み付け時の概略斜視図および概略断面図Schematic perspective view and schematic sectional view when assembling the handle member (Example 2) 把手部材（従来構成）の概略斜視図Schematic perspective view of handle member (conventional configuration) 軸部材と把手部材（従来構成）近傍の概略斜視図および概略断面図Schematic perspective view and schematic sectional view of the vicinity of the shaft member and the handle member (conventional configuration) 把手部材（従来例）組み付け時の概略斜視図および概略断面図Schematic perspective view and schematic sectional view when assembling the handle member (conventional example)

［実施例１］
以下に図面を参照して、本発明の好適な実施の形態を例示的に詳しく説明する。ただし、この実施の形態に記載されている構成部品の寸法や材質、形状、その相対配置などは、特に特定的な記載がない限り、この発明の範囲をそれらのみに限定する主旨のものではない。 [Example 1]
Exemplary embodiments of the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

＜画像形成装置の全体的な構成及び動作＞
図１は本発明が適用された画像形成装置１００として、４つの画像形成部を有する中間転写方式のタンデム型カラーデジタルプリンタを正面から見た概略断面図である。まず、画像形成装置１００の概略について説明する。 <Overall Configuration and Operation of Image Forming Apparatus>
FIG. 1 is a schematic cross-sectional view of an intermediate transfer type tandem color digital printer having four image forming units as viewed from the front, as an image forming apparatus 100 to which the present invention is applied. First, an outline of the image forming apparatus 100 will be described.

画像形成装置１００は、その中段位置に中間転写ベルト１７を張架支持した中間転写ベルトユニット１０を備えている。また中間転写ベルトユニット１０の下には、中間転写ベルト１７にそれぞれイエロー、マゼンタ、シアン、ブラックのトナー像を形成する画像形成部１０６ａ〜１０６ｄが備えられる。画像形成部１０６ａ〜１０６ｄには、それぞれ像担持体として感光体ドラム１０１ａ〜１０１ｄを備え、帯電ローラ１０２ａ〜１０２ｄにより表面を一様な電荷に帯電される。レーザスキャナ１０３ａ〜１０３ｄにはそれぞれイエロー、マゼンタ、シアン、ブラックの画像信号が入力され、画像信号に応じて感光体ドラム１０１ａ〜１０１ｄの表面をレーザ光で照射し、電荷を中和して静電潜像を形成する。静電潜像はそれぞれ現像器１０４ａ〜１０４ｄによって各色のトナー像として顕在化された後、中間転写ベルト１７へ順に１次転写され、中間転写ベルト１７上にフルカラーのトナー像が形成される。また感光体ドラム１０１ａ〜１０１ｄ上に残存したトナー剤はドラムクリーナ１０５ａ〜１０５ｄにより回収される。 The image forming apparatus 100 includes an intermediate transfer belt unit 10 in which an intermediate transfer belt 17 is stretched and supported at a middle position. Under the intermediate transfer belt unit 10, image forming units 106 a to 106 d for forming yellow, magenta, cyan, and black toner images on the intermediate transfer belt 17 are provided. The image forming units 106a to 106d are respectively provided with photosensitive drums 101a to 101d as image carriers, and the surfaces are charged with uniform charges by the charging rollers 102a to 102d. Image signals of yellow, magenta, cyan, and black are input to the laser scanners 103a to 103d, respectively, and the surfaces of the photosensitive drums 101a to 101d are irradiated with laser light in accordance with the image signals to neutralize charges and electrostatically A latent image is formed. The electrostatic latent images are visualized as toner images of respective colors by the developing devices 104 a to 104 d, respectively, and then primary transferred sequentially to the intermediate transfer belt 17 to form a full color toner image on the intermediate transfer belt 17. The toner agent remaining on the photosensitive drums 101a to 101d is collected by the drum cleaners 105a to 105d.

一方、給送部１１１、１１２もしくは手差し給送部１１３のいずれかから給紙された紙等の被転写材Ｐが給紙ローラ１１０、フィードローラ１１４およびリタードローラ１１５を介して一枚ずつレジストローラ対１１６へと送られる。停止しているレジストローラに対して被転写材Ｐの先端が突き当たるとループを形成し、中間転写ベルト１７上のトナー像と同期してレジストローラを回転開始させる。 On the other hand, the transfer material P such as paper fed from any of the feeding units 111 and 112 or the manual feeding unit 113 is fed one by one through the feeding roller 110, the feed roller 114, and the retard roller 115. Sent to pair 116. When the leading edge of the transfer material P comes into contact with the stopped registration roller, a loop is formed, and the registration roller is started to rotate in synchronization with the toner image on the intermediate transfer belt 17.

中間転写ベルト１７上のトナー像は、被転写材Ｐに２次転写外ローラ１０８と中間転写ベルト１７が形成する２次転写部１０７で転写され、定着装置１０９で熱及び圧力により定着される。その後、被転写材Ｐは排紙部１１７ａもしくは１１７ｂから機外の排紙トレイ１１８ａ、１１８ｂへと排出される。また、２次転写部１０７において転写されず、中間転写ベルト１７上に残存したトナー剤は、中間転写ベルトクリーナ５０により回収される。 The toner image on the intermediate transfer belt 17 is transferred to the transfer material P by the secondary transfer outer roller 108 and the secondary transfer portion 107 formed by the intermediate transfer belt 17 and fixed by the fixing device 109 by heat and pressure. Thereafter, the transfer material P is discharged from the paper discharge unit 117a or 117b to the paper discharge trays 118a and 118b outside the apparatus. Further, the toner agent that is not transferred in the secondary transfer unit 107 and remains on the intermediate transfer belt 17 is collected by the intermediate transfer belt cleaner 50.

＜中間転写ベルトユニット＞
次に、図２〜図６を使用して中間転写ベルトユニット１０について説明する。図２はフルカラー画像形成時における中間転写ベルトユニット１０の概略断面図である。図３はモノクロ画像形成時（第一の状態）における中間転写ベルトユニット１０の概略断面図である。図４は、ベルト交換等のメンテナンス時に位置される、第二の状態における中間転写ベルトユニット１０の概略断面図である。図５は中間転写ベルトユニット１０を持ち運ぶ際の状態を表した概略斜視図、図６は中間転写ベルトユニット１０の把手部材周辺の構成を表した概略斜視図を表している。 <Intermediate transfer belt unit>
Next, the intermediate transfer belt unit 10 will be described with reference to FIGS. FIG. 2 is a schematic cross-sectional view of the intermediate transfer belt unit 10 during full color image formation. FIG. 3 is a schematic cross-sectional view of the intermediate transfer belt unit 10 during monochrome image formation (first state). FIG. 4 is a schematic cross-sectional view of the intermediate transfer belt unit 10 in the second state, which is located during maintenance such as belt replacement. FIG. 5 is a schematic perspective view showing a state when the intermediate transfer belt unit 10 is carried, and FIG. 6 is a schematic perspective view showing a configuration around the grip member of the intermediate transfer belt unit 10.

図２〜４に示すように、ポリイミド等を用いた中間転写ベルト１７は、２次転写内ローラ１１、ステアリングローラ１２、テンションローラ１３、補助ローラ１４およびアイドラローラ１５の５本のローラにより張架されている。これらのローラ１１〜１５は両端で軸受（不図示）により回転可能に支持される。なお、本実施形態においてステアリングローラ１２は駆動ローラとしての機能も兼ねており、同じ符号を付して説明する。ただし、必ずしもステアリングローラ１２を駆動ローラとする必要はなく、例えば図２においてアイドラローラ１５や２次転写内ローラ１１を駆動ローラとした場合にも有効である。 2 to 4, the intermediate transfer belt 17 using polyimide or the like is stretched by five rollers including a secondary transfer inner roller 11, a steering roller 12, a tension roller 13, an auxiliary roller 14, and an idler roller 15. Has been. These rollers 11 to 15 are rotatably supported by bearings (not shown) at both ends. In this embodiment, the steering roller 12 also functions as a driving roller, and will be described with the same reference numerals. However, it is not always necessary to use the steering roller 12 as a driving roller. For example, the idler roller 15 or the secondary transfer inner roller 11 shown in FIG.

駆動ローラ１２の表面は、中間転写ベルト１７を滑り無く搬送するために、摩擦係数の高いゴム層で形成されている。また、中間転写ベルト１７は、テンションローラ１３によってベルト内面から加圧されることでテンションが付与される。駆動ローラを兼ねるステアリングローラ１２が回転駆動することで、中間転写ベルト１７は反時計回り（図２の矢印２００参照）に周回搬送される。 The surface of the driving roller 12 is formed of a rubber layer having a high friction coefficient so as to convey the intermediate transfer belt 17 without slipping. The intermediate transfer belt 17 is applied with tension by being pressed from the inner surface of the belt by the tension roller 13. The intermediate transfer belt 17 is conveyed in a counterclockwise direction (see an arrow 200 in FIG. 2) when the steering roller 12 also serving as a driving roller is rotationally driven.

中間転写ベルト１７を張架するアイドラローラ１５と補助ローラ１４との間には、各色の感光体ドラム１０１ａ〜１０１ｄと対向する位置に１次転写ローラ１６ａ〜１６ｄが配置される。１次転写ローラ１６ａ〜１６ｄは、各両端を軸受（不図示）によって回転可能に支持されるとともに、弾性部材（不図示）により中間転写ベルト２２を内面から加圧する。これにより、中間転写ベルト１７は、１次転写ローラ１６ａ〜１６ｄと感光ドラム１０１ａ〜１０１ｄで挟持される（図２参照）。 Between the idler roller 15 and the auxiliary roller 14 that stretch the intermediate transfer belt 17, primary transfer rollers 16 a to 16 d are disposed at positions facing the photosensitive drums 101 a to 101 d of the respective colors. The primary transfer rollers 16a to 16d are rotatably supported at both ends by bearings (not shown), and pressurize the intermediate transfer belt 22 from the inner surface by elastic members (not shown). Thus, the intermediate transfer belt 17 is sandwiched between the primary transfer rollers 16a to 16d and the photosensitive drums 101a to 101d (see FIG. 2).

＜感光ドラムの離間機構＞
中間転写ベルトユニット１０は、中間転写ベルト１７と少なくとも一つの感光体ドラムが接触した第一の状態と、中間転写ベルト１７と全ての感光体ドラムが離間した第二の状態とに切替可能に構成される。第一の状態と第二の状態の切替は、中間転写ベルトユニット１０に回動可能に備えられた軸部材２０の回動によって行われる。即ち、軸部材２０が回転することで、中間転写ベルト１７と感光体ドラムの当接及び離間可能に構成されている。本実施形態では、軸部材２０の回転は、軸部材２０に固定されたレバーを操作者が回すことで第一の状態から第二の状態の切り替えが行われるように構成されている。尚、本実施形態では、第一の状態から第二の状態へ切替を行う場合を説明したが、これに限定されない。例えば、図２のように、各色の感光ドラム１０１を中間転写ベルト１７に当接する状態（全当接状態）から第二の状態への切り替えを軸部材２０で行う構成にも適用できる。中間転写ベルトユニット１０の第一の状態と第二の状態との切替の動作について、以下にさらに詳しく説明する。中間転写ベルトユニット１０には、画像形成装置正面から見て左端に配置されるイエローの１次転写ローラ１６ａの左外側部に張架ローラの軸線方向と略平行に支持軸２７が備えられる。支持軸２７にはフレームユニット１８に備えられた支持部材２８の収納部２８ａが係合し、フレームユニット１８は支持部材２８を介して支持軸２７を回動中心に回動可能である。また、中間転写ベルトユニット１０には、張架ローラの軸線方向と略平行に軸部材２０が両端部近傍を回動可能に支持されるよう備えられ、さらにその両端部近傍には移動部材２５が固定される。移動部材２５には案内溝２５ａが備えられ、案内溝２５ａは曲面形状であり、軸部材２０からの距離が移動部材２５の回動角度に応じて徐々に変化するカムとなっている。一方で、画像形成装置正面から見てベルトフレームユニット１８の前側と奥側の両側面部には、その外側に突出した案内軸２６が備えられ、案内軸２６は案内溝２５ａと係合するよう構成されている（図３参照）。中間転写ベルトユニット１０の第一の状態において、軸部材２０を画像形成装置正面から見て反時計回り方向に回動させると、それに連動して移動部材２５および案内溝２５ａが軸部材２０を回動中心に反時計回り方向に回動する。この時、案内溝２５ａにはフレームユニット１８の案内軸２６が係合しており、案内軸２６は軸部材２０の回動によって案内溝２５ａの曲面に接触しながら略重力方向上方に移動する。これにより、フレームユニット１８は支持軸２７を回動中心に、案内軸２６の移動を介して反時計回り方向に回動する。軸部材２０の回動動作が完了すると、フレームユニット１８に備えられた中間転写ベルト１７と全ての感光体ドラム１０１ａ〜１０１ｄが離間し中間転写ベルトユニット１０は第二の状態となる（図４参照）。 <Photosensitive drum separation mechanism>
The intermediate transfer belt unit 10 is configured to be switchable between a first state in which the intermediate transfer belt 17 and at least one photosensitive drum are in contact with each other and a second state in which the intermediate transfer belt 17 and all the photosensitive drums are separated from each other. Is done. Switching between the first state and the second state is performed by rotation of a shaft member 20 that is rotatably provided to the intermediate transfer belt unit 10. That is, when the shaft member 20 rotates, the intermediate transfer belt 17 and the photosensitive drum can be brought into contact with and separated from each other. In the present embodiment, the rotation of the shaft member 20 is configured such that the operator switches the first state to the second state by turning a lever fixed to the shaft member 20. In addition, although this embodiment demonstrated the case where it switches from a 1st state to a 2nd state, it is not limited to this. For example, as shown in FIG. 2, the shaft member 20 can also be applied to switch from a state in which the photosensitive drum 101 of each color is in contact with the intermediate transfer belt 17 (all contact state) to the second state. The operation of switching between the first state and the second state of the intermediate transfer belt unit 10 will be described in more detail below. The intermediate transfer belt unit 10 is provided with a support shaft 27 on the left outer side of the yellow primary transfer roller 16a disposed at the left end when viewed from the front of the image forming apparatus, substantially parallel to the axial direction of the stretching roller. The support shaft 27 engages with a storage portion 28 a of a support member 28 provided in the frame unit 18, and the frame unit 18 can rotate around the support shaft 27 via the support member 28. Further, the intermediate transfer belt unit 10 is provided with a shaft member 20 supported so as to be rotatable in the vicinity of both end portions substantially parallel to the axial direction of the stretching roller, and further, a moving member 25 is provided in the vicinity of both end portions. Fixed. The moving member 25 is provided with a guide groove 25a. The guide groove 25a has a curved surface, and is a cam whose distance from the shaft member 20 gradually changes according to the rotation angle of the moving member 25. On the other hand, both front and back side surface portions of the belt frame unit 18 as viewed from the front of the image forming apparatus are provided with guide shafts 26 protruding outward, and the guide shafts 26 are configured to engage with the guide grooves 25a. (See FIG. 3). In the first state of the intermediate transfer belt unit 10, when the shaft member 20 is rotated counterclockwise as viewed from the front of the image forming apparatus, the moving member 25 and the guide groove 25a rotate the shaft member 20 in conjunction with the rotation. It rotates counterclockwise about the center of movement. At this time, the guide shaft 26 of the frame unit 18 is engaged with the guide groove 25a, and the guide shaft 26 moves substantially upward in the gravitational direction while contacting the curved surface of the guide groove 25a by the rotation of the shaft member 20. As a result, the frame unit 18 rotates counterclockwise around the support shaft 27 via the movement of the guide shaft 26. When the rotation of the shaft member 20 is completed, the intermediate transfer belt 17 provided in the frame unit 18 and all the photosensitive drums 101a to 101d are separated from each other, and the intermediate transfer belt unit 10 is in the second state (see FIG. 4). ).

中間転写ベルトユニット１０は、中間転写ベルト１７と全ての感光体ドラムが離間する第二の状態となっているときに装置本体から着脱可能に構成されている。中間転写ベルトユニット１０を第二の状態にすると、中間転写ベルト１７と感光体ドラム１０１ａ〜１０１ｄや中間転写ベルトユニット１０の重力方向下方に備えられる構成部品との距離が確保される。このため、画像形成装置主本体部から中間転写ベルトユニット１０を着脱する際に作業性が良い。本実施形態における中間転写ユニット１０の画像形成装置主本体部に対する着脱方向は、画像形成装置正面から見て前側に引き出す方向である。即ち、中間転写ベルトユニット１０は、感光体ドラム１０１ａ〜１０１ｄの軸線方向と直交する側面に設けられた開口部を通じて、着脱可能である。中間転写ベルトユニット１０を画像形成装置主本体部から引き出した後は、中間転写ベルトユニット１０に備えられた把手部材２１と把手部１９を支持し、中間転写ベルトユニット１０の持ち運びを容易にする（図５参照）。 The intermediate transfer belt unit 10 is configured to be detachable from the apparatus main body when in the second state in which the intermediate transfer belt 17 and all the photosensitive drums are separated. When the intermediate transfer belt unit 10 is in the second state, the distance between the intermediate transfer belt 17 and the photosensitive drums 101a to 101d and components provided below the intermediate transfer belt unit 10 in the gravity direction is secured. Therefore, workability is good when the intermediate transfer belt unit 10 is attached to and detached from the main body of the image forming apparatus. In the present embodiment, the attachment / detachment direction of the intermediate transfer unit 10 with respect to the main body of the image forming apparatus is a direction in which the intermediate transfer unit 10 is pulled out to the front side when viewed from the front of the image forming apparatus. That is, the intermediate transfer belt unit 10 is detachable through an opening provided on a side surface orthogonal to the axial direction of the photosensitive drums 101a to 101d. After the intermediate transfer belt unit 10 is pulled out from the main body of the image forming apparatus, the handle member 21 and the handle portion 19 provided in the intermediate transfer belt unit 10 are supported to facilitate the carrying of the intermediate transfer belt unit 10 ( (See FIG. 5).

＜ベルトユニットの把手部材＞
図５に示すように、把手部１９は、中間転写ベルト１７の鉛直方向上方に配置されている。把手部１９は、軸部材２０の軸線方向と直交する方向からみたとき、中間転写ベルト１７と重なる位置に設けられている。把手部材２１は、軸部材２０を回動中心として回動可能に軸部材２０に備えられる。軸部材２０には、軸部材２０と把手部材２１とが係合する位置に第一の軸部２０ａが備えられ、その他の位置に第二の軸部２０ｂが備えられる。即ち、軸部材２０は、把手部材２１が中間転写ベルトユニット１０に装着されているときに、貫通穴の内部に位置される第一の軸部２０ａを有する。また、軸部材２０は、把手部材２１が中間転写ベルトユニット１０に装着されているときに、貫通穴の外部に位置される第二の軸部２０ｂを有する。第一の軸部２０ａの外径は第二の軸部２０ｂよりも小さい形状であり、そのため、第一の軸部２０ａに係合する把手部材２１の外形の小型化が可能となる。第一の軸部２０ａに対する把手部材２１のラジアル方向の位置決めの詳しい構成は後述する。また、中間転写ベルトユニット１０には、軸部材２０両端部を回動可能に支持するフレーム部材２３が備えられ、フレーム部材２３には把手部材２１を収納可能な収納部２３ａが備えられる。把手部材２１の軸部材２０軸線方向における位置は、収納部２３ａに備えられた位置規制部２３ｂ、２３ｃと把手部材２１の側面部２１ｄ、２１ｅとが当接することによって規制される。軸部材２０には弾性部材２４が係合し、把手部材２１は弾性部材２４によって収納部２３ａに収納される方向（軸部材２０の周方向）に弾性付勢されている（図６参照）。これにより、中間転写ベルトユニット１０を持ち運ぶ際には、把手部材２１は軸部材２０を回動中心にして、弾性部材２４による弾性力に抗して持ち上げられる。それ以外では、把手部材２１は収納部２３ａに常に収納されるため、中間転写ベルトユニット１０の小型化を実現できる。 <Belt unit handle member>
As shown in FIG. 5, the handle portion 19 is disposed above the intermediate transfer belt 17 in the vertical direction. The handle portion 19 is provided at a position overlapping the intermediate transfer belt 17 when viewed from a direction orthogonal to the axial direction of the shaft member 20. The handle member 21 is provided in the shaft member 20 so as to be rotatable about the shaft member 20 as a rotation center. The shaft member 20 includes a first shaft portion 20a at a position where the shaft member 20 and the handle member 21 are engaged, and a second shaft portion 20b at other positions. That is, the shaft member 20 has the first shaft portion 20a positioned inside the through hole when the handle member 21 is attached to the intermediate transfer belt unit 10. Further, the shaft member 20 has a second shaft portion 20 b positioned outside the through hole when the handle member 21 is attached to the intermediate transfer belt unit 10. The outer diameter of the first shaft portion 20a is smaller than that of the second shaft portion 20b. Therefore, the outer shape of the handle member 21 that engages with the first shaft portion 20a can be reduced. A detailed configuration of the radial positioning of the handle member 21 with respect to the first shaft portion 20a will be described later. Further, the intermediate transfer belt unit 10 is provided with a frame member 23 that rotatably supports both end portions of the shaft member 20, and the frame member 23 is provided with a storage portion 23 a in which the handle member 21 can be stored. The position of the handle member 21 in the axial direction of the shaft member 20 is restricted by the position restricting portions 23b and 23c provided in the storage portion 23a and the side surface portions 21d and 21e of the handle member 21 coming into contact with each other. An elastic member 24 is engaged with the shaft member 20, and the handle member 21 is elastically urged by the elastic member 24 in a direction in which the handle member 21 is stored in the storage portion 23a (a circumferential direction of the shaft member 20) (see FIG. 6). Thus, when carrying the intermediate transfer belt unit 10, the handle member 21 is lifted against the elastic force of the elastic member 24 with the shaft member 20 as the rotation center. In other cases, the handle member 21 is always stored in the storage portion 23a, so that the intermediate transfer belt unit 10 can be downsized.

＜把手部材の組み付け及び位置決め＞
次に、図７〜１０を使用して、本実施形態の構成における軸部材２０に対する把手部材２１の組み付けとラジアル方向の位置決めについて説明する。図７は把手部材の概略斜視図である。図８は軸部材２０のＤカット部２０ｄ周辺部の概略斜視図である。 <Assembly and positioning of handle members>
Next, assembly of the handle member 21 with respect to the shaft member 20 and positioning in the radial direction in the configuration of the present embodiment will be described with reference to FIGS. FIG. 7 is a schematic perspective view of the handle member. FIG. 8 is a schematic perspective view of the periphery of the D-cut portion 20 d of the shaft member 20.

図９（ａ）は軸部材２０に対して把手部材２１が組付けられた状態の概略斜視図である。図９（ｂ）は図９（ａ）の状態においての平面部２０ｃに平行な面の断面を表した概略断面図である。図９（ｃ）は図９（ａ）の状態での把手部材２１係合部の概略断面図である。 FIG. 9A is a schematic perspective view of a state in which the handle member 21 is assembled to the shaft member 20. FIG. 9B is a schematic cross-sectional view showing a cross section of a plane parallel to the planar portion 20c in the state of FIG. 9A. FIG.9 (c) is a schematic sectional drawing of the handle member 21 engaging part in the state of Fig.9 (a).

図１０（ａ−１）は本実施形態での組み立てにおいて第二の貫通穴２１ｂ内に第二の軸部２０ｂが通過している様子を表した概略斜視図である。図１０（ａ−２）は図１０（ａ−１）の状態において平面部２０ｃに平行な面の断面を表した概略断面図である。 FIG. 10A-1 is a schematic perspective view showing a state where the second shaft portion 20b passes through the second through hole 21b in the assembly according to the present embodiment. FIG. 10A-2 is a schematic cross-sectional view showing a cross section of a plane parallel to the plane portion 20c in the state of FIG.

図１０（ｂ−１）は第一の軸部２０ａのＤカット部２０ｄ（図８参照）と突起部２１ｃが対向している状態の概略斜視図である。図１０（ｂ−２）は図１０（ｂ−１）の状態において平面部２０ｃに平行な面の断面を表した概略断面図である。 FIG. 10B-1 is a schematic perspective view of a state in which the D-cut portion 20d (see FIG. 8) of the first shaft portion 20a faces the protrusion 21c. FIG. 10B-2 is a schematic cross-sectional view showing a cross section of a plane parallel to the plane portion 20c in the state of FIG.

図１０（ｃ−１）は第一の貫通穴２１ａに第一の軸部２０ａが移動した様子を表した概略斜視図である。図１０（ｃ−２）は図１０（ｃ−１）の状態において平面部２０ｃに平行な面の断面を表した概略断面図である。図１０（ｃ−３）は、図１０（ｃ−１）の状態における把手部材２１係合部の概略断面図である。 FIG. 10C-1 is a schematic perspective view showing a state where the first shaft portion 20a has moved to the first through hole 21a. FIG. 10C-2 is a schematic cross-sectional view showing a cross section of a plane parallel to the plane portion 20c in the state of FIG. FIG.10 (c-3) is a schematic sectional drawing of the handle member 21 engaging part in the state of FIG.10 (c-1).

軸部材２０は、軸部材２０の軸線方向において把手部材２１が係合する位置に第一の軸部２０ａ、係合する位置よりも外側である他の位置に第二の軸部２０ｂを備える。第一の軸部２０ａの外径は第二の軸部２０ｂの外径よりも小さい。また、第一の軸部２０ａには、平面部２０ｃを含むＤカット部２０ｄが備えられる。Ｄカット部２０ｄは、所定方向の厚みが第一の軸部２０ａの軸径よりも小さい。Ｄカット部２０ｄは、軸部材２０の軸線を中心とした円弧部と、軸部材２０の軸線と平行の平面部２０ｃとを有する。把手部材２１には軸部材２０の軸線方向に向かって貫通穴が備えられ、軸部材２０が挿入可能に構成されている。貫通穴には、把手部材２１が装着されたときに軸部材２０の第一の軸部２０ａに嵌合可能な第一の貫通穴２１ａ（第一穴部）と、第二の軸部２０ｂが通過可能な第二の貫通穴２１ｂ（第二穴部）を有する。第一の貫通穴２１ａと第二の貫通穴２１ｂは、軸部材２０の軸線方向と直交する方向で互いに連通している。即ち、第一の貫通穴２１ａと第二の貫通穴２１ｂの間に連通部が形成されている。第一の貫通穴２１ａと第二の貫通穴２１ｂの間には、突起部２１ｃが備えられる。第一の貫通穴２１ａと突起部２１ｃで囲われた貫通穴は、第一の軸部２０ａが嵌合する大きさである。 The shaft member 20 includes a first shaft portion 20a at a position where the handle member 21 is engaged in the axial direction of the shaft member 20, and a second shaft portion 20b at another position outside the engaging position. The outer diameter of the first shaft portion 20a is smaller than the outer diameter of the second shaft portion 20b. Further, the first shaft portion 20a is provided with a D-cut portion 20d including a flat surface portion 20c. The D cut portion 20d has a thickness in a predetermined direction smaller than the shaft diameter of the first shaft portion 20a. The D-cut portion 20 d has an arc portion centered on the axis of the shaft member 20 and a plane portion 20 c parallel to the axis of the shaft member 20. The handle member 21 is provided with a through hole in the axial direction of the shaft member 20 so that the shaft member 20 can be inserted. The through hole has a first through hole 21a (first hole portion) that can be fitted into the first shaft portion 20a of the shaft member 20 when the handle member 21 is mounted, and a second shaft portion 20b. It has the 2nd through-hole 21b (2nd hole part) which can pass. The first through hole 21 a and the second through hole 21 b communicate with each other in a direction orthogonal to the axial direction of the shaft member 20. That is, a communication portion is formed between the first through hole 21a and the second through hole 21b. A protrusion 21c is provided between the first through hole 21a and the second through hole 21b. The through hole surrounded by the first through hole 21a and the protrusion 21c has a size that allows the first shaft portion 20a to be fitted.

即ち、本実施例では、貫通穴の内面は、第一の貫通穴２１ａと第二の貫通穴２１ｂの間で、貫通穴の間隙が狭くなるように貫通穴の内面から突出する突起部２１ｃが形成されている。 That is, in the present embodiment, the inner surface of the through hole has a protrusion 21c protruding from the inner surface of the through hole so that the gap between the through holes is narrowed between the first through hole 21a and the second through hole 21b. Is formed.

突起部２１ｃは、軸部材２０の軸線方向における幅がＤカット部２０ｄの溝幅（平面２０ｃの軸線方向長さ）よりも小さい幅である。第一の貫通穴２１ａと突起部２１ｃで形成された隙間Ｈ１の距離は、平面部２０ｃと第一の軸部２０ａの外径部との厚みＨ２よりも大きい関係となっている（図７〜９参照）。 The protrusion 21c has a width in the axial direction of the shaft member 20 that is smaller than the groove width of the D-cut portion 20d (length in the axial direction of the flat surface 20c). The distance between the gap H1 formed by the first through hole 21a and the protrusion 21c is larger than the thickness H2 between the flat portion 20c and the outer diameter portion of the first shaft portion 20a (FIGS. 7 to 7). 9).

また、第一の貫通穴２１ａと突起部２１ｃで形成された隙間Ｈ１の距離は、第一の軸部２０ａの外径よりも小さい。ここで、隙間Ｈ１の距離が広すぎると、把手部材２１を軸部材２０に取り付けた後に、軸部材２０が第二の貫通穴２１ｂ側に外れてしまう。一方、隙間Ｈ１の距離が狭すぎると、Ｄカット部２０ｄの厚みＨ２が小さくなりすぎてしまう。そこで、本実施例では、隙間Ｈ１の距離は、第一の軸部２０ａの外径−１ｍｍと第一の軸部２０ａの外径×６０％の間としている。好ましくは、隙間Ｈ１の距離は、第一の軸部２０ａの外径−１．５ｍｍと第一の軸部２０ａの外径−２．５ｍｍの間である。言い換えれば、隙間Ｈ１の距離と第一の軸部２０ａの外径との差分は、１ｍｍよりも大きく、第一の軸部２０ａの外径の４０未満であることが好ましい。また、隙間Ｈ１の距離と第一の軸部２０ａの外径との差分は、１．５ｍｍよりも大きく、２．５ｍｍ未満がより好ましい。 Moreover, the distance of the clearance gap H1 formed of the 1st through-hole 21a and the projection part 21c is smaller than the outer diameter of the 1st axial part 20a. Here, if the distance of the gap H <b> 1 is too large, the shaft member 20 comes off to the second through hole 21 b side after the handle member 21 is attached to the shaft member 20. On the other hand, when the distance of the gap H1 is too narrow, the thickness H2 of the D-cut portion 20d becomes too small. Therefore, in the present embodiment, the distance of the gap H1 is between the outer diameter of the first shaft portion 20a −1 mm and the outer diameter of the first shaft portion 20a × 60%. Preferably, the distance of the gap H1 is between the outer diameter of the first shaft portion 20a -1.5 mm and the outer diameter of the first shaft portion 20a -2.5 mm. In other words, the difference between the distance of the gap H1 and the outer diameter of the first shaft portion 20a is preferably greater than 1 mm and less than 40 of the outer diameter of the first shaft portion 20a. The difference between the distance of the gap H1 and the outer diameter of the first shaft portion 20a is greater than 1.5 mm and more preferably less than 2.5 mm.

次に、軸部材２０と把手部材２１の組付けについて説明する。まず、把手部材２１の第二の貫通穴２１ｂ内に軸部材２０の第二の軸部２０ｂを軸方向に通過させる。本実施形態における軸部材２０通過の方向は、画像形成装置正面から見て奥側から前側に向かう方向である（図１０（ａ）参照）。第二の貫通穴２１ｂに第二の軸部２０ｂを軸方向に通過させていくと第一の軸部２０ａのＤカット部２０ｄと突起部２１ｃが対向する（図１０（ｂ）参照）。この状態から第一の軸部２０ａは、平面部２０ｃと第一の軸部２０ａの外径部との厚みＨ２が第一の貫通穴２１ａと突起部２１ｃで形成された隙間Ｈ１を通過して、第二の貫通穴２１ｂから第一の貫通穴２１ａに移動する（図１０（ｃ）参照）。第一の軸部２０ａが第一の貫通穴２１ａ内に移動した後、さらに第一の軸部２０ａを第一の貫通穴２１ａに対して軸部材２０の軸線方向に通過させる。なお、その通過の方向は、画像形成装置正面から見て奥側から前側に向かう方向である。第一の軸部２０ａを第一の貫通穴２１ａに対して軸部材２０の軸線方向に通過させ、Ｄカット部２０ｃと突起部２１ｃが対向する位置でなくなると、第一の軸部２０ａは、貫通穴２１ａと突起部２０ｃによって囲われた貫通穴に嵌合した状態となる。これにより、把手部材２１は軸部材２０に対してラジアル方向の位置決めがなされ、軸部材２０を回動中心に回動することが可能になる（図９参照）。 Next, assembly of the shaft member 20 and the handle member 21 will be described. First, the second shaft portion 20b of the shaft member 20 is passed through the second through hole 21b of the handle member 21 in the axial direction. The direction of passage of the shaft member 20 in the present embodiment is a direction from the back side to the front side when viewed from the front of the image forming apparatus (see FIG. 10A). When the second shaft portion 20b passes through the second through hole 21b in the axial direction, the D-cut portion 20d and the projection portion 21c of the first shaft portion 20a face each other (see FIG. 10B). From this state, in the first shaft portion 20a, the thickness H2 between the flat surface portion 20c and the outer diameter portion of the first shaft portion 20a passes through the gap H1 formed by the first through hole 21a and the protruding portion 21c. Then, the second through hole 21b moves to the first through hole 21a (see FIG. 10C). After the first shaft portion 20a moves into the first through hole 21a, the first shaft portion 20a is further passed in the axial direction of the shaft member 20 with respect to the first through hole 21a. The direction of the passage is a direction from the back side to the front side when viewed from the front of the image forming apparatus. When the first shaft portion 20a is passed through the first through hole 21a in the axial direction of the shaft member 20, and the D-cut portion 20c and the protruding portion 21c are not at positions facing each other, the first shaft portion 20a is It will be in the state fitted to the through hole enclosed by the through hole 21a and the projection part 20c. As a result, the grip member 21 is positioned in the radial direction with respect to the shaft member 20, and can be rotated around the shaft member 20 (see FIG. 9).

また、本実施形態では、第二の貫通穴２１ｂ内に第二の軸部２０ｂを通過させる方向と第一の貫通穴２１ａ内に第一の軸部２０ａを通過させる方向とが同じである。上述の通過方向が同じでないと、同じである時と比較して、第二の貫通穴２１ｂ内に第二の軸部２０ｂを通過させる移動量が大きくなる。軸部材２０の移動量が大きくなると、中間転写ベルトユニット１０に組み付けられる他の構成部品の配置に制限が掛かり、装置の複雑化や大型化をもたらす。本実施形態では、上述の通過方法を同じにすることで、装置の複雑化や大型化を抑制している。 In the present embodiment, the direction in which the second shaft portion 20b passes through the second through hole 21b and the direction in which the first shaft portion 20a passes through the first through hole 21a are the same. If the above-mentioned passing directions are not the same, the amount of movement for allowing the second shaft portion 20b to pass through the second through hole 21b becomes larger than when the passing directions are the same. When the amount of movement of the shaft member 20 is increased, the arrangement of other components assembled to the intermediate transfer belt unit 10 is restricted, resulting in a complicated and large apparatus. In this embodiment, complication and enlargement of the apparatus are suppressed by using the same passing method.

ここで、本実施形態における把手部材２１に設けられる第一の貫通穴２１ａと第二の貫通穴２１ｂと中間転写ベルト１７との位置関係について、説明する。本実施形態では、把手部材２１と軸部材２０を第一の貫通穴２１ａで嵌合支持された場合における把手部材２１と中間転写ベルト１７の距離は、第１距離に設定されている。この第１距離は、把手部材２１と軸部材２０（第二の軸部２０ｂ）を第二の貫通穴２１ｂで嵌合させたときの把手部材２１と中間転写ベルト１７の第２距離よりも大きい関係となっている。このため、第一の軸部２０ａと第一の貫通穴２１ａを嵌合させることで把手部材２１と中間転写ベルト１７との距離を広げることができ、装置の大型化を抑制することができる。 Here, the positional relationship among the first through hole 21a, the second through hole 21b, and the intermediate transfer belt 17 provided in the handle member 21 in the present embodiment will be described. In the present embodiment, the distance between the handle member 21 and the intermediate transfer belt 17 when the handle member 21 and the shaft member 20 are fitted and supported by the first through hole 21a is set to the first distance. The first distance is larger than the second distance between the handle member 21 and the intermediate transfer belt 17 when the handle member 21 and the shaft member 20 (second shaft portion 20b) are fitted in the second through hole 21b. It has become a relationship. For this reason, the distance between the handle member 21 and the intermediate transfer belt 17 can be increased by fitting the first shaft portion 20a and the first through hole 21a, and the size of the apparatus can be suppressed.

具体的に本実施形態では、把手部材２１が収納部２３ａに収納されたときにおいて、第一の貫通穴２１ａと第二の貫通穴２１ｂの中間転写ベルト１７に対する位置関係は以下のように設定されている。即ち、中間転写ベルト１７を軸部材２０の鉛直方向下方に配置している。更に、把手部材２１が収納部２３ａに収納されたときの第一の貫通穴２１ａの最下点位置と、第二の貫通穴２１ｂの最下点位置を略同じ高さに設定している。こうすることで、把手部材２１を取り付けた際の把手部材２１と中間転写ベルト１７の距離を第一の軸部２０ａと第二の軸部２０ｂの軸径の差分だけ広げることができる。尚、本実施例では、把手部材２１が収納部２３ａに収納されたときの第一の貫通穴２１ａの最下点位置と、第二の貫通穴２１ｂの最下点位置の高さを同じ位置としたが、これに限定されない。本実施形態のように中間転写ベルトが下方に位置する場合であれば、第一の貫通穴２１ａの最下点位置が、第二の貫通穴２１ｂの最下点位置よりも下方もしくは上方であってもよい。第一の貫通穴２１ａの最下点位置が、第二の貫通穴２１ｂの最下点位置よりも上方に位置する場合は、最下点位置の高低差が第一の軸部２０ａと第二の軸部２０ｂの軸径の差分以下に設定される。こうすれば把手部材２１と中間転写ベルト１７の距離を広げる効果を得ることができる。また、本実施例では、軸部材２０の下方に中間転写ベルト１７が配置される場合を例に説明したがこれに限定されない。把手部材２１が収納部２３ａに収納されているときの第一の貫通穴２１ａと中間転写ベルト１７との最近接距離をＬ１とする。また、第二の貫通穴２１ｂと中間転写ベルト１７との最近接距離をＬ２とする。また、第一の軸部２０ａと第二の軸部２０ｂの軸径の差分をＬ３とする。このとき、Ｌ１＜Ｌ２＋Ｌ３を満たすように構成すれば把手部材２１と中間転写ベルト１７の距離を広げることができる。 Specifically, in the present embodiment, when the handle member 21 is stored in the storage portion 23a, the positional relationship between the first through hole 21a and the second through hole 21b with respect to the intermediate transfer belt 17 is set as follows. ing. That is, the intermediate transfer belt 17 is disposed below the shaft member 20 in the vertical direction. Furthermore, the lowest point position of the first through hole 21a and the lowest point position of the second through hole 21b when the handle member 21 is stored in the storage part 23a are set to substantially the same height. By doing so, the distance between the handle member 21 and the intermediate transfer belt 17 when the handle member 21 is attached can be increased by the difference between the shaft diameters of the first shaft portion 20a and the second shaft portion 20b. In this embodiment, the height of the lowest point position of the first through hole 21a and the lowest point position of the second through hole 21b when the handle member 21 is stored in the storage portion 23a are the same position. However, it is not limited to this. If the intermediate transfer belt is positioned downward as in the present embodiment, the lowest point position of the first through hole 21a is lower or higher than the lowest point position of the second through hole 21b. May be. When the lowest point position of the first through hole 21a is located higher than the lowest point position of the second through hole 21b, the difference in height of the lowest point position is the first shaft portion 20a and the second shaft part 20a. It is set to be equal to or less than the difference in the shaft diameter of the shaft portion 20b. In this way, the effect of increasing the distance between the grip member 21 and the intermediate transfer belt 17 can be obtained. In this embodiment, the case where the intermediate transfer belt 17 is disposed below the shaft member 20 has been described as an example, but the present invention is not limited to this. Let L1 be the closest distance between the first through hole 21a and the intermediate transfer belt 17 when the handle member 21 is stored in the storage portion 23a. The closest distance between the second through hole 21b and the intermediate transfer belt 17 is L2. Further, the difference between the shaft diameters of the first shaft portion 20a and the second shaft portion 20b is L3. At this time, if it is configured to satisfy L1 <L2 + L3, the distance between the handle member 21 and the intermediate transfer belt 17 can be increased.

また、本実施形態では、中間転写ベルトユニット１０を持ち運ぶ際における軸部材２０は、平面部２０ｃが重力方向と略平行になる回動位相としている。即ち、軸部材２０の位相が、第二の状態（中間転写ベルト１７と全ての感光体ドラムが離間した状態）に対応する位相のときに、平面部２０ｃと重力方向のなす角が２０°以内に設定されている。即ち、軸部材２０の位相が、中間転写ベルトユニット１０が装置本体から着脱可能となるときの位相のときに、平面部２０ｃと重力方向のなす角が２０°以内に設定されている。また、より好ましくは、軸部材２０の位相が、中間転写ベルトユニット１０が装置本体から着脱可能となるときの位相のときに、平面部２０ｃと重力方向なす角が１０°以内に設定されている。把手部材２１を介して軸部材２０に与えられる中間転写ユニット１０の重量による負荷は略重力方向上向きとなる。これにより、軸部材２０に負荷が与えられる箇所の曲げに対する断面２次モーメントが比較的大きくなり、変形・破断に対する許容力の低下を抑制している。 In the present embodiment, the shaft member 20 when carrying the intermediate transfer belt unit 10 has a rotational phase in which the flat portion 20c is substantially parallel to the direction of gravity. That is, when the phase of the shaft member 20 is a phase corresponding to the second state (the state where the intermediate transfer belt 17 and all the photosensitive drums are separated), the angle formed by the flat surface portion 20c and the gravitational direction is within 20 °. Is set to That is, when the phase of the shaft member 20 is a phase when the intermediate transfer belt unit 10 is detachable from the apparatus main body, the angle formed by the flat surface portion 20c and the gravitational direction is set within 20 °. More preferably, when the phase of the shaft member 20 is a phase when the intermediate transfer belt unit 10 is detachable from the apparatus main body, the angle formed by the flat surface portion 20c and the gravitational direction is set within 10 °. . The load due to the weight of the intermediate transfer unit 10 applied to the shaft member 20 via the handle member 21 is substantially upward in the gravitational direction. Thereby, the cross-sectional secondary moment with respect to the bending of the place where the load is applied to the shaft member 20 becomes relatively large, and the reduction of the allowable force against deformation and fracture is suppressed.

本実施形態によれば、把手部材２１の貫通穴に設けられた突起部２１ｃと、軸部材２０に設けられたＤカット部２０ｄの位置が軸線方向でずれた位置で、軸部材２０と把手部材２１が組み付けられる。こうすることで、把手部材２１を取り付けた後に、軸部材２０が第一の貫通穴２１ａから外れて第二の貫通穴２１ｂに移動してしまうことを抑制できる。また、軸部材２０が第一の貫通穴２１ａから外れて第二の貫通穴２１ｂに移動してしまうことを抑制すべく、新たな部品を必要としないため、部品点数の増加を抑制することができる。 According to the present embodiment, the shaft member 20 and the handle member are located at positions where the positions of the protrusion 21c provided in the through hole of the handle member 21 and the D-cut portion 20d provided on the shaft member 20 are shifted in the axial direction. 21 is assembled. By carrying out like this, after attaching the handle member 21, it can suppress that the shaft member 20 remove | deviates from the 1st through-hole 21a, and moves to the 2nd through-hole 21b. Moreover, since it does not require a new component in order to suppress that the shaft member 20 remove | deviates from the 1st through-hole 21a, and moves to the 2nd through-hole 21b, it can suppress the increase in a number of parts. it can.

＜参考例＞
ここで、参考例として、第一の軸部２０ａと第一の貫通穴２１ａとの嵌合が外れないように別途固定部材を設けて、把手部材のスラスト位置決めを行う構成について図１３〜１５を使用して説明する。図１３は把手部材２２１の概略斜視図である。図１４（ａ）は軸部材２２０に対して把手部材２２１が組付けられた状態の概略斜視図である。図８（ｂ）は図１４（ａ）の状態での把手部材２２１係合部の概略断面図である。図１５（ａ）は組み立てにおいて第二の貫通穴２２１ｂ内に第二の軸部２２０ｂが通過している様子を表した概略斜視図である。図１５（ｂ）は第二の貫通穴２２１ｂ内に第一の軸部２２０ａが通過している様子を表した概略斜視図である。図１５（ｃ）は第一の貫通穴２２１ａに第一の軸部２２０ａが移動し固定部材２２２を組み付ける時の様子を表した概略斜視図である。 <Reference example>
Here, as a reference example, FIGS. 13 to 15 show a configuration in which a separate fixing member is provided so that the fitting between the first shaft portion 20a and the first through hole 21a is not removed and the handle member is thrust-positioned. Use and explain. FIG. 13 is a schematic perspective view of the handle member 221. FIG. 14A is a schematic perspective view of a state in which the handle member 221 is assembled to the shaft member 220. FIG. 8B is a schematic cross-sectional view of the handle member 221 engaging portion in the state of FIG. FIG. 15A is a schematic perspective view showing a state where the second shaft portion 220b passes through the second through hole 221b during assembly. FIG. 15B is a schematic perspective view showing a state where the first shaft portion 220a passes through the second through hole 221b. FIG. 15C is a schematic perspective view showing a state when the first shaft portion 220a moves to the first through hole 221a and the fixing member 222 is assembled.

軸部材２２０は、軸部材２２０の軸線方向において把手部材２２１が係合する位置に第一の軸部２２０ａ、その他の位置に第二の軸部２２０ｂを備え、第一の軸部２２０ａの外径は第二の軸部２２０ｂの外径よりも小さい。把手部材２２１には軸部材２２０が貫通する貫通穴が備えられ、貫通穴には軸部材２２０の第一の軸部２２０ａに嵌合する幅の第一の貫通穴２２１ａと第二の軸部２２０ｂが通過可能な第二の貫通穴２２１ｂが備えられる。第一の貫通穴２２１ａと第二の貫通穴２２１ｂは、それらの間を第一の軸部２２０ａが移動可能になるよう連結している。さらに、把手部材２２１には、固定部材２２２が係合する固定部材係合部２２１ｃ、２２１ｄが備えられる。把手部材２２１に固定部材２２２が係合した状態では、第一の貫通穴２２１ａと第二の貫通穴２２１ｂの間は固定部材２２２によって仕切られ、第一の貫通穴２２１ａと固定部材２２２で囲われた貫通穴は、第一の軸部２２０ａが嵌合する大きさである（図１３、図１４参照）。 The shaft member 220 includes a first shaft portion 220a at a position where the handle member 221 engages in the axial direction of the shaft member 220, and a second shaft portion 220b at other positions, and the outer diameter of the first shaft portion 220a. Is smaller than the outer diameter of the second shaft portion 220b. The handle member 221 is provided with a through hole through which the shaft member 220 passes, and the through hole has a first through hole 221a and a second shaft portion 220b having a width that fits the first shaft portion 220a of the shaft member 220. Is provided with a second through hole 221b. The first through hole 221a and the second through hole 221b are connected so that the first shaft part 220a can move between them. Further, the handle member 221 is provided with fixing member engaging portions 221c and 221d with which the fixing member 222 is engaged. When the fixing member 222 is engaged with the handle member 221, the first through hole 221 a and the second through hole 221 b are partitioned by the fixing member 222, and are surrounded by the first through hole 221 a and the fixing member 222. The through hole has a size with which the first shaft portion 220a is fitted (see FIGS. 13 and 14).

次に、軸部材２２０と把手部材２２１の組付けについて説明する。まず、把手部材２２１の第二の貫通穴２２１ｂ内に軸部材２２０の第二の軸部２２０ｂを軸線方向に通過させる（図１５（ａ）参照）。第二の貫通穴２２１ｂに第二の軸部２２０ｂを軸線方向に通過させていくと第二の貫通穴２２１ｂ内に第一の軸部２２０ａが通過する（図１５（ｂ）参照）。第二の貫通穴２２１ｂ内に第一の軸部２２０ａが通過する状態において、第一の軸部２２０ａは第二の貫通穴２２１ｂから第一の貫通穴２２１ａに移動する。ここで、固定部材２２２を把手部材２２１の固定部材係合部２２１ｃ、２２１ｄに組み付けると、第一の軸部２２０ａは、第一の貫通穴２２１ａと固定部材２２２とで囲われた貫通穴内に嵌合する状態となる（図１４、図１５（ｃ）参照）。これにより、把手部材２２１は軸部材２２０に対してラジアル方向の位置決めがなされ、軸部材２２０を回動中心に回動することが可能になる。また、第一の軸部２２０ａと第二の軸部２２０ｂの外径差分だけ把手部材２２１の外形を小さくし把手部材２２１をベルト部材から離すことができるため、機能を損なうことなくユニットの小型化と操作性を兼ね備えることができる。 Next, assembly of the shaft member 220 and the handle member 221 will be described. First, the second shaft portion 220b of the shaft member 220 is passed through the second through hole 221b of the handle member 221 in the axial direction (see FIG. 15A). When the second shaft portion 220b passes through the second through hole 221b in the axial direction, the first shaft portion 220a passes through the second through hole 221b (see FIG. 15B). In a state where the first shaft portion 220a passes through the second through hole 221b, the first shaft portion 220a moves from the second through hole 221b to the first through hole 221a. Here, when the fixing member 222 is assembled to the fixing member engaging portions 221c and 221d of the handle member 221, the first shaft portion 220a is fitted in the through hole surrounded by the first through hole 221a and the fixing member 222. (See FIGS. 14 and 15 (c)). Thereby, the grip member 221 is positioned in the radial direction with respect to the shaft member 220, and can be rotated about the shaft member 220 as a rotation center. Further, since the outer shape of the handle member 221 can be reduced by the difference in outer diameter between the first shaft portion 220a and the second shaft portion 220b and the handle member 221 can be separated from the belt member, the size of the unit can be reduced without impairing the function. And operability.

しかし、上述の構成では軸部材２２０と把手部材２２１の他に、位置決めのための固定部材２２２が必要となり部品点数が増えコストが高くなる問題がある。 However, the above-described configuration requires a fixing member 222 for positioning in addition to the shaft member 220 and the handle member 221, and there is a problem that the number of parts increases and the cost increases.

［実施例２］
実施例１に対して、把手部材２１の貫通穴の形状が異なるものである。本実施形態は、実施例１における軸部材２０に対する把手部材２１の組み立て性を良くするものである。図１１、１２を使用して、本実施形態の構成について詳しく説明する。 [Example 2]
The shape of the through hole of the handle member 21 is different from that of the first embodiment. This embodiment improves the assemblability of the handle member 21 with respect to the shaft member 20 in the first embodiment. The configuration of this embodiment will be described in detail with reference to FIGS.

図１１は、本実施形態における把手部材２１の概略斜視図である。図１２（ａ）は第一の貫通穴２１ａに第一の軸部２０ａが移動した様子を表した概略斜視図、図１２（ｂ）は、図１２（ａ）の状態における把手部材２１係合部の概略断面図である。 FIG. 11 is a schematic perspective view of the handle member 21 in the present embodiment. FIG. 12A is a schematic perspective view showing a state in which the first shaft portion 20a has moved to the first through hole 21a, and FIG. 12B shows the engagement of the handle member 21 in the state of FIG. It is a schematic sectional drawing of a part.

把手部材２１には軸部材２０の軸線方向に向かって貫通穴が備えられ、貫通穴には軸部材２０の第一の軸部２０ａに嵌合する幅の第一の貫通穴２１ａ（第１の形状部）と第二の軸部２０ｂが通過可能な第二の貫通穴２１ｂ（第２の形状部）を有する。第一の貫通穴２１ａと第二の貫通穴２１ｂの間には、突起部２１ｃが備えられる。第一の貫通穴２１ａと突起部２１ｃで囲われた貫通穴は、第一の軸部２０ａが嵌合する大きさである。 The handle member 21 is provided with a through hole in the axial direction of the shaft member 20, and the through hole has a first through hole 21 a having a width that fits the first shaft portion 20 a of the shaft member 20 (first And a second through hole 21b (second shape part) through which the second shaft part 20b can pass. A protrusion 21c is provided between the first through hole 21a and the second through hole 21b. The through hole surrounded by the first through hole 21a and the protrusion 21c has a size that allows the first shaft portion 20a to be fitted.

突起部２１ｃは、軸部材２０の軸線方向における幅がＤカット部２０ｄの溝幅よりも小さい幅である。突起部２１ｃの対向面側には突起部２１ｆが備えられ、突起部２１ｃと突起部２１ｆで形成された隙間Ｈ３の距離は、平面部２０ｃと第一の軸部２０ａの外径部との厚みＨ２よりも小さい関係となっている（図１１参照）。 The protrusion 21c has a width in the axial direction of the shaft member 20 that is smaller than the groove width of the D-cut portion 20d. A protruding portion 21f is provided on the opposite surface side of the protruding portion 21c, and the distance of the gap H3 formed by the protruding portion 21c and the protruding portion 21f is the thickness between the flat surface portion 20c and the outer diameter portion of the first shaft portion 20a. The relationship is smaller than H2 (see FIG. 11).

軸部材２０に対する把手部材２１の組み付けにおいて、第一の軸部２０ａが第二の貫通穴２１ｂから第一の貫通穴２１ａに移動する際は、Ｄカット部２０ｄが突起部２１ｃと突起部２１ｆで形成された隙間Ｈ３を通過する。そのため、第一の軸部２０ａは第一の貫通穴２１ａ内に突起部２１ｆによって仮止めされた状態となる。これにより、第一の軸部２０ａが第一の貫通穴２１ａから第二の貫通穴２１ｂに戻る方向に移動することを抑制する。したがって、次の組み立て動作である第一の貫通穴２１ａに対して第一の軸部２０ａを通過させる際に、Ｄカット部２１ｄの平面部２１ｃに直交して形成される側面部が突起部２１ｃの側面に当接し作業の障害となることを抑制できる。このため、作業性が良くなる（図１２参照）。 In assembling the handle member 21 to the shaft member 20, when the first shaft portion 20a moves from the second through hole 21b to the first through hole 21a, the D-cut portion 20d is formed by the protrusion portion 21c and the protrusion portion 21f. It passes through the formed gap H3. Therefore, the first shaft portion 20a is temporarily fixed in the first through hole 21a by the protrusion 21f. Thereby, it is suppressed that the 1st axial part 20a moves to the direction which returns to the 2nd through-hole 21b from the 1st through-hole 21a. Accordingly, when the first shaft portion 20a is passed through the first through hole 21a which is the next assembling operation, the side surface portion formed perpendicular to the flat surface portion 21c of the D-cut portion 21d is the projection portion 21c. It can suppress that it contacts the side surface of this and becomes an obstacle of work. For this reason, workability | operativity improves (refer FIG. 12).

本実施例では、第一の貫通穴２１ａと突起部２１ｃで形成された隙間Ｈ１の距離は、平面部２０ｃと第一の軸部２０ａの外径部との厚みＨ２よりも大きい関係となっている例で説明したが、これに限定されない。上記隙間Ｈ１は、上記厚みＨ２よりも小さい関係であっても、Ｄカット部２１ｄが隙間Ｈ１を移動可能な範囲であればよい。例えば、隙間Ｈ１と厚みＨ２の差分が１ｍｍ以下であれば、Ｄカット部２１ｄが隙間Ｈ１を移動可能とすることができる。 In the present embodiment, the distance of the gap H1 formed by the first through hole 21a and the protruding portion 21c is larger than the thickness H2 between the flat surface portion 20c and the outer diameter portion of the first shaft portion 20a. However, the present invention is not limited to this. Even if the gap H1 has a smaller relationship than the thickness H2, it is sufficient that the D-cut portion 21d can move within the gap H1. For example, if the difference between the gap H1 and the thickness H2 is 1 mm or less, the D-cut portion 21d can move the gap H1.

本実施例では、第一の軸部２０ａと第二の軸部の断面は、いずれも円形を例に説明したが、必ずしもこれに限定されない。例えば、軸と直交する断面を楕円形状としてもよい。 In the present embodiment, the first shaft portion 20a and the second shaft portion have a circular cross section as an example, but the present invention is not necessarily limited thereto. For example, the cross section orthogonal to the axis may be elliptical.

１０中間転写ベルトユニット
１１２次転写内ローラ
１２ステアリングローラ（駆動ローラ）
１３テンションローラ
１４補助ローラ
１５アイドラローラ
１６ａ〜１６ｄ１次転写ローラ
１７中間転写ベルト
２０軸部材
２０ａ第一の軸部
２０ｂ第二の軸部
２０ｃ平面部
２０ｄＤカット部
２１把手部材
２１ａ第一の貫通穴
２１ｂ第二の貫通穴
２１ｃ突起部
２１ｄ、２１ｅ側面部
２１ｆ突起部
１００画像形成装置
２００ベルト周回方向
２２０軸部材
２２０ａ第一の軸部
２２０ｂ第二の軸部
２２１把手部材
２２１ａ第一の貫通穴
２２１ｂ第二の貫通穴
２２１ｃ固定部材係合部
２２１ｄ固定部材係合部
２２２固定部材
Ｈ１第一の貫通穴と突起部２１ｃの隙間
Ｈ２平面部と第一の軸部の外径部との厚み
Ｈ３突起部２１ｃと突起部２１ｆで形成された隙間 10 Intermediate transfer belt unit 11 Secondary transfer inner roller 12 Steering roller (drive roller)
13 Tension roller 14 Auxiliary roller 15 Idler rollers 16a to 16d Primary transfer roller 17 Intermediate transfer belt 20 Shaft member 20a First shaft portion 20b Second shaft portion 20c Planar portion 20d D cut portion 21 Handle member 21a First penetration Hole 21b Second through hole 21c Protruding part 21d, 21e Side face part 21f Protruding part 100 Image forming apparatus 200 Belt circumferential direction 220 Shaft member 220a First shaft part 220b Second shaft part 221 Handle member 221a First through hole 221b Second through hole 221c Fixing member engaging part 221d Fixing member engaging part 222 Fixing member H1 A gap between the first through hole and the protruding part 21c H2 Thickness between the flat part and the outer diameter part of the first shaft part H3 The gap formed by the protrusion 21c and the protrusion 21f

Claims

画像を担持する像担持体と、
装置本体に着脱可能に設けられ、前記像担持体が担持するトナー像が転写されるベルトを備えたベルトユニットと、
前記ベルトユニットに回動可能に設けられ、前記ベルトユニットを装置本体から取り出す際に前記ベルトユニットを把手するための把手部と、
前記ベルトユニットに設けられ、前記把手部に設けられた貫通穴に挿入されて前記把手部を回動可能に支持する軸と、を備えた画像形成装置であって、
前記軸は、第一の軸部と、前記第一の軸部よりも太い第二の軸部と、を備え、
前記貫通穴は、前記第一の軸部が嵌合可能な第一穴部と、前記軸の軸線方向と直交する方向に関して前記第一穴部とは異なる位置に設けられ、前記第二の軸部が挿入可能な第二穴部と、前記第一穴部と前記第二穴部を連通させる連通部と、を備え、
前記把手部が前記ベルトユニットに装着されているときに前記第一の軸部と対向する位置に設けられ、前記連通部の間隙が前記第一の軸部の外径よりも狭くなるように前記貫通穴の内面から突出する突起部を備え、
前記軸は、前記軸の軸線方向と直交する所定方向の厚みが前記第一の軸部よりも小さく、前記軸の軸線方向の長さが前記突起部よりも長い第三の軸部を備え、前記第三の軸部が前記突起部と対向する位置にあるとき、前記軸が前記連通部を通過可能に構成されている、
ことを特徴とする画像形成装置。 An image carrier for carrying an image;
A belt unit including a belt that is detachably provided in the apparatus main body and onto which a toner image carried by the image carrier is transferred;
A handle portion provided rotatably on the belt unit, for gripping the belt unit when the belt unit is removed from the apparatus main body;
An image forming apparatus comprising: a shaft provided in the belt unit and inserted into a through hole provided in the handle portion and rotatably supporting the handle portion;
The shaft includes a first shaft portion and a second shaft portion thicker than the first shaft portion,
The through hole is provided at a position different from the first hole portion with respect to a first hole portion into which the first shaft portion can be fitted and a direction orthogonal to the axial direction of the shaft, and the second shaft A second hole part into which the part can be inserted, and a communication part for communicating the first hole part and the second hole part,
The grip portion is provided at a position facing the first shaft portion when the handle unit is attached to the belt unit, and the gap of the communication portion is narrower than the outer diameter of the first shaft portion. Protruding from the inner surface of the through hole,
The shaft includes a third shaft portion whose thickness in a predetermined direction orthogonal to the axial direction of the shaft is smaller than that of the first shaft portion, and whose length in the axial direction of the shaft is longer than that of the protruding portion, When the third shaft portion is at a position facing the protrusion, the shaft is configured to pass through the communication portion.
An image forming apparatus.

前記突起部により前記連通部に形成される隙間と前記第一の軸部の軸径との差は、１．５ｍｍよりも大きく、２．５ｍｍよりも小さい、ことを特徴とする請求項１に記載の画像形成装置。 The difference between the gap formed in the communication portion by the protrusion and the shaft diameter of the first shaft portion is larger than 1.5 mm and smaller than 2.5 mm. The image forming apparatus described.

前記突起部により前記連通部に形成される隙間Ｈ１は、前記第三の軸部の前記所定方向の厚さＨ２よりも大きいことを特徴とする請求項１または２に記載の画像形成装置。 3. The image forming apparatus according to claim 1, wherein a gap H <b> 1 formed in the communication portion by the protrusion is larger than a thickness H <b> 2 of the third shaft portion in the predetermined direction.

前記軸が回転することで前記ベルトと前記像担持体が当接、離間可能に構成されており、前記第三の軸部は、前記軸の軸線方向に平行の平面部と、前記軸の軸線を中心とした円弧部と、を備え、前記軸の位相が、前記ベルトユニットが装置本体から着脱可能となる位相にあるとき、前記平面部と重力方向のなす角は、２０°以内であることを特徴とする請求項１乃至３の何れか１項に記載の画像形成装置。 The belt and the image carrier can be contacted and separated by rotating the shaft, the third shaft portion includes a plane portion parallel to the axial direction of the shaft, and the axis of the shaft. And when the phase of the shaft is in a phase that allows the belt unit to be attached to and detached from the apparatus main body, the angle formed by the plane portion and the gravitational direction is within 20 °. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

前記像担持体の軸線方向と直交する側面に設けられた開口部を備え、前記ベルトユニットは、前記開口部を通じて装置本体から着脱可能に設けられていることを特徴とする請求項１乃至４の何れか１項に記載の画像形成装置。 5. The apparatus according to claim 1, further comprising an opening provided on a side surface orthogonal to the axial direction of the image carrier, wherein the belt unit is detachably provided from the apparatus main body through the opening. The image forming apparatus according to claim 1.

前記把手部は、前記ベルトの鉛直方向上方で、前記軸の軸線方向と直交する方向からみたとき、ベルトと重なる位置に設けられていることを特徴とする請求項１乃至５の何れか１項に記載の画像形成装置。 The said handle | steering-wheel part is provided in the position which overlaps with a belt when it sees from the direction orthogonal to the axial direction of the said axis | shaft above the perpendicular direction of the said belt. The image forming apparatus described in 1.

前記軸線方向に直交する断面において、前記第一穴部と前記ベルトとの最近接距離をＬ１とし、前記第二穴部と前記ベルトとの最近接距離をＬ２とし、前記第一の軸部と前記第二の軸部の外径の差分をＬ３としたとき、Ｌ１＜Ｌ２＋Ｌ３を満たすことを特徴とする請求項１乃至６の何れか１項に記載の画像形成装置。 In the cross section perpendicular to the axial direction, the closest distance between the first hole and the belt is L1, the closest distance between the second hole and the belt is L2, and the first shaft is The image forming apparatus according to claim 1, wherein L1 <L2 + L3 is satisfied, where L3 is a difference in outer diameter of the second shaft portion.

前記軸の軸線方向に関して、前記第一の軸部及び前記第三の軸部は、前記第二の軸部に挟まれる位置に設けられている、ことを特徴とする請求項１乃至７の何れか１項に記載の画像形成装置。 8. The axial direction of the shaft, wherein the first shaft portion and the third shaft portion are provided at a position sandwiched between the second shaft portions. The image forming apparatus according to claim 1.