JP2018004731A

JP2018004731A - Image forming apparatus

Info

Publication number: JP2018004731A
Application number: JP2016127449A
Authority: JP
Inventors: 宏信大井; Hironobu Oi
Original assignee: Kyocera Document Solutions Inc
Current assignee: Kyocera Document Solutions Inc
Priority date: 2016-06-28
Filing date: 2016-06-28
Publication date: 2018-01-11
Anticipated expiration: 2036-06-28
Also published as: JP6524975B2

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can suppress a reduction in print image quality caused by lack of elimination of static electricity on image carriers, while suppressing an increase in size and cost of the apparatus.SOLUTION: An image forming apparatus comprises: image carriers that each carry a toner image; light sources that each emit light used for elimination of static electricity on the image carrier; and static elimination parts that each guide the light emitted from the light sources and made incident on one ends along the longitudinal direction and emit static elimination light toward the image carrier. The static elimination parts each emit, in a first area in the longitudinal direction of the light guide member, static elimination light with an intensity larger than that in a second area. The first area is an area where the toner contamination level is expected to be higher than that in the second area.SELECTED DRAWING: Figure 8

Description

本発明は、除電部を備える電子写真方式の画像形成装置に関する。 The present invention relates to an electrophotographic image forming apparatus including a static elimination unit.

電子写真方式の画像形成装置は、感光体ドラム等の像担持体の表面を除電する除電部を備える。前記除電部は、前記感光体ドラムの回転軸方向に沿って配置された長尺の導光部材と、前記導光部材の端部に向けて光を出射する光源とを備える場合がある。 An electrophotographic image forming apparatus includes a static eliminating unit that neutralizes the surface of an image carrier such as a photosensitive drum. The static elimination unit may include a long light guide member disposed along the rotation axis direction of the photosensitive drum and a light source that emits light toward an end of the light guide member.

前記導光部材は、その周辺要素である現像部、現像部に供給するトナーを収容したトナーコンテナ、これらの連結部分等から飛散したトナーにより汚染され得る。一方、前記導光部材がトナーの付着により汚染されると、前記導光部材からの出射光量が低下する。そのため、前記像担持体の表面の除電が不十分となり、これが印刷画質の劣化を引き起こす原因となる。そこで、トナー汚染による除電光の強度低下を抑制すべく、除電部を清掃することも提案されている（例えば、特許文献１参照）。 The light guide member may be contaminated by toner scattered from a developing unit which is a peripheral element thereof, a toner container containing toner to be supplied to the developing unit, and a connecting part thereof. On the other hand, when the light guide member is contaminated by the adhesion of toner, the amount of light emitted from the light guide member decreases. For this reason, the surface of the image carrier is not sufficiently neutralized, which causes a deterioration in print image quality. In view of this, it has been proposed to clean the static eliminating portion in order to suppress the intensity reduction of the static elimination light due to toner contamination (see, for example, Patent Document 1).

特開２００５−５５６７７号公報JP-A-2005-55677

しかしながら、除電部を清掃する構成を採用すると、装置構成の複雑化を招き、装置の大型化やコストアップの原因となる。また、装置構成によっては、清掃時に除電部が損傷する可能性がある。導光部材の損傷は、除電光量が低下する原因ともなりかねない。 However, adopting a configuration for cleaning the static elimination unit leads to complication of the device configuration, which causes an increase in size and cost of the device. In addition, depending on the device configuration, the static eliminator may be damaged during cleaning. Damage to the light guide member may also cause a reduction in the amount of static elimination light.

本発明の目的は、装置の大型化やコストアップを抑制しつつ、像担持体の除電不足に起因する印刷画質の低下を抑制できる画像形成装置を提供することにある。 An object of the present invention is to provide an image forming apparatus capable of suppressing a decrease in print image quality due to insufficient charge removal of an image carrier while suppressing an increase in size and cost of the apparatus.

本発明の一の局面に係る画像形成装置は、像担持体と、除電部とを備える。前記像担持体は、トナー像を担持する。前記除電部は、光源及び導光部材を有する。前記光源は、前記像担持体の除電に用いられる光を出射する。前記導光部材は、前記光源から一端に入射される光を長手方向に沿って導くと共に前記像担持体に向けて除電光を出射する。前記除電部は、前記導光部材における前記長手方向の第１領域において第２領域よりも大きい光量の除電光を出射する。前記第１領域は、前記第２領域よりもトナー汚染度が高くなることが予想される領域である。 An image forming apparatus according to one aspect of the present invention includes an image carrier and a charge removal unit. The image carrier carries a toner image. The static elimination unit includes a light source and a light guide member. The light source emits light used for neutralizing the image carrier. The light guide member guides light incident on one end from the light source along the longitudinal direction and emits static elimination light toward the image carrier. The static elimination unit emits a static elimination light having a larger light amount than the second area in the first area in the longitudinal direction of the light guide member. The first area is an area where the degree of toner contamination is expected to be higher than that of the second area.

本発明によれば、装置の大型化やコストアップを抑制しつつ、像担持体の除電不足に起因する印刷画質の低下を抑制できる画像形成装置を提供することが可能となる。 According to the present invention, it is possible to provide an image forming apparatus capable of suppressing a decrease in print image quality due to insufficient charge removal of an image carrier while suppressing an increase in size and cost of the apparatus.

図１は、本発明の実施形態に係る画像形成装置の構成図である。FIG. 1 is a configuration diagram of an image forming apparatus according to an embodiment of the present invention. 図２は、本発明の実施形態に係る画像形成装置が備える画像形成ユニットの一例の構成図である。FIG. 2 is a configuration diagram of an example of an image forming unit provided in the image forming apparatus according to the embodiment of the present invention. 図３は、画像形成ユニットの平面図である。FIG. 3 is a plan view of the image forming unit. 図４は、画像形成ユニットの除電部の一例を示す平面図である。FIG. 4 is a plan view illustrating an example of a charge removal unit of the image forming unit. 図５は、図４に示される導光部材におけるＶ−Ｖ切断線の部分の断面図である。FIG. 5 is a cross-sectional view of a VV cutting line portion in the light guide member shown in FIG. 4. 図６は、図４に示される導光部材におけるＶＩ−ＶＩ切断線の部分の断面図である。6 is a cross-sectional view of a VI-VI cutting line portion in the light guide member shown in FIG. 図７は、除電光量と、除電後の感光体ドラムの表面電位との関係を示すグラフである。FIG. 7 is a graph showing the relationship between the charge removal amount and the surface potential of the photosensitive drum after charge removal. 図８は、導光部材の長手方向における出射光量分布の一例を示すグラフである。FIG. 8 is a graph showing an example of the emitted light amount distribution in the longitudinal direction of the light guide member. 図９は、除電部の他の例の要部を示す断面図である。FIG. 9 is a cross-sectional view illustrating a main part of another example of the charge removal unit. 図１０は、除電部の他の応用例を示す断面図である。FIG. 10 is a cross-sectional view illustrating another application example of the charge removal unit. 図１１は、除電部の他の応用例を示す平面図である。FIG. 11 is a plan view illustrating another application example of the charge removal unit. 図１２は、除電部の他の応用例を示す平面図である。FIG. 12 is a plan view illustrating another application example of the charge removal unit. 図１３は、除電部の他の応用例を示す平面図である。FIG. 13 is a plan view illustrating another application example of the charge removal unit. 図１４は、除電部の他の応用例を示す断面図である。FIG. 14 is a cross-sectional view illustrating another application example of the charge removal unit. 図１５は、除電部の他の応用例を示す断面図である。FIG. 15 is a cross-sectional view illustrating another application example of the charge removal unit.

以下、添付図面を参照しながら、本発明の実施の形態について説明し、本発明の理解に供する。なお、以下の実施の形態は、本発明を具体化した一例であって、本発明の技術的範囲を限定する性格のものではない。 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. In addition, the following embodiment is an example which actualized this invention, Comprising: The thing of the character which limits the technical scope of this invention is not.

［第１の実施形態］
図１に示すように、画像形成装置１０は、複数の画像形成ユニット１１（１１Ｙ，１１Ｃ，１１Ｍ，１１Ｋ）、中間転写ベルト１２、光走査装置１３、二次転写ローラー１４、定着装置１５、排紙トレイ１６、給紙カセット１７、搬送経路１８及びトナーコンテナ１９等を備える。画像形成装置１０は、給紙カセット１７から搬送経路１８に沿って供給されるシートに、パーソナルコンピューター等の情報処理装置から入力される画像データに基づくカラー画像又はモノクロ画像を形成するカラープリンターである。また、ファクシミリー、コピー機、及び複合機等も、本発明に係る画像形成装置の一例である。 [First Embodiment]
As shown in FIG. 1, the image forming apparatus 10 includes a plurality of image forming units 11 (11Y, 11C, 11M, and 11K), an intermediate transfer belt 12, an optical scanning device 13, a secondary transfer roller 14, a fixing device 15, and a discharge device. A paper tray 16, a paper feed cassette 17, a transport path 18, a toner container 19 and the like are provided. The image forming apparatus 10 is a color printer that forms a color image or a monochrome image based on image data input from an information processing apparatus such as a personal computer on a sheet supplied from a sheet feeding cassette 17 along a conveyance path 18. . In addition, a facsimile machine, a copier, and a multifunction machine are examples of the image forming apparatus according to the present invention.

画像形成ユニット１１は、中間転写ベルト１２の進行方向Ｄ１に沿って並設されており、所謂タンデム方式によりシートに画像を形成する。具体的に、画像形成ユニット１１Ｙではイエロー色のトナー像が形成される。また、画像形成ユニット１１Ｃ，１１Ｍ，１１Ｂのそれぞれでは、シアン色のトナー像、マゼンタ色のトナー像、黒色のトナー像がそれぞれ形成される。例えば、中間転写ベルト１２の進行方向Ｄ１の上流側から順に、イエロー用の画像形成ユニット１１Ｙ、シアン色用の画像形成ユニット１１Ｃ、マゼンタ色用の画像形成ユニット１１Ｍ、及び黒色用の画像形成ユニット１１Ｋがその順番で一列に配置されている。なお、進行方向Ｄ１は、中間転写ベルト１２の下面が進む方向である。 The image forming units 11 are arranged in parallel along the traveling direction D1 of the intermediate transfer belt 12, and form an image on a sheet by a so-called tandem method. Specifically, a yellow toner image is formed in the image forming unit 11Y. In each of the image forming units 11C, 11M, and 11B, a cyan toner image, a magenta toner image, and a black toner image are formed. For example, the image forming unit 11Y for yellow, the image forming unit 11C for cyan, the image forming unit 11M for magenta, and the image forming unit 11K for black are sequentially arranged from the upstream side in the traveling direction D1 of the intermediate transfer belt 12. Are arranged in a line in that order. The traveling direction D1 is a direction in which the lower surface of the intermediate transfer belt 12 travels.

図２に示すように、画像形成ユニット１１は、感光体ドラム２、帯電部３、現像部４、除電部５、一次転写ローラー６、及びクリーニング部７を備える。 As shown in FIG. 2, the image forming unit 11 includes a photosensitive drum 2, a charging unit 3, a developing unit 4, a charge eliminating unit 5, a primary transfer roller 6, and a cleaning unit 7.

感光体ドラム２は、中間転写ベルト１２の進行方向Ｄ１に沿って並設されている。感光体ドラム２は、静電潜像及びトナー像を担持する像担持体であり、中間転写ベルト１２の下面に接触しつつ中間転写ベルト１２と共に回転する。 The photosensitive drums 2 are arranged in parallel along the traveling direction D1 of the intermediate transfer belt 12. The photosensitive drum 2 is an image carrier that carries an electrostatic latent image and a toner image, and rotates with the intermediate transfer belt 12 while being in contact with the lower surface of the intermediate transfer belt 12.

帯電部３は、不図示の電源から供給される電力により対応する感光体ドラム２を帯電させる帯電ローラー３１を有する。そして、帯電部３により帯電された感光体ドラム２に、光走査装置１３によってレーザー光が照射され、画像データに基づく静電潜像が感光体ドラム２の外周面に形成される。 The charging unit 3 includes a charging roller 31 that charges the corresponding photosensitive drum 2 with power supplied from a power source (not shown). The photosensitive drum 2 charged by the charging unit 3 is irradiated with laser light by the optical scanning device 13, and an electrostatic latent image based on the image data is formed on the outer peripheral surface of the photosensitive drum 2.

現像部４は、感光体ドラム２に形成された前記静電潜像をトナー（現像剤）により現像する現像ローラー４１を有する。現像部４には、感光体ドラム２の軸方向の一方の端部にトナー導入口４２が形成されており、各色に対応するトナーコンテナ１９（１９Ｙ，１９Ｃ，１９Ｍ，１９Ｋ）からトナーが補給される。なお、感光体ドラム２の軸方向は、後述の導光部材５２の長手方向Ｄ２に平行な方向である。 The developing unit 4 includes a developing roller 41 that develops the electrostatic latent image formed on the photosensitive drum 2 with toner (developer). In the developing unit 4, a toner introduction port 42 is formed at one end of the photosensitive drum 2 in the axial direction, and toner is supplied from the toner containers 19 (19 Y, 19 C, 19 M, and 19 K) corresponding to the respective colors. The The axial direction of the photosensitive drum 2 is a direction parallel to a longitudinal direction D2 of a light guide member 52 described later.

トナーコンテナ１９は、現像部４に供給する未使用のトナーを収容するものである。トナーコンテナ１９は、本体部１９１及び搬送部１９２を有する。本体部１９１は、前記トナーを収容しており、現像部４における長手方向Ｄ２の一方側の側方に配置されている。搬送部１９２は、スクリュー機構等の公知の機構により本体部１９１のトナーを現像部４に向けて搬送する。搬送部１９２は、トナー排出口１９３を有している。トナー排出口１９３は、現像部４における前記一方の端部よりの部位に設けられ、現像部４のトナー導入口４２に連結されている。即ち、トナー排出口１９３及びトナー導入口４２は、互いに結合され連結部９を構成する。トナーコンテナ１９では、本体部１９１に収容されたトナーが、搬送部１９２によりトナー排出口１９３まで搬送され、連結部９を介して現像部４に導入される。なお、トナーコンテナ１９は、現像部４に供給するトナーに加えて、クリーニング部７で回収された廃トナーを収容するものであってもよい。 The toner container 19 stores unused toner to be supplied to the developing unit 4. The toner container 19 includes a main body 191 and a transport unit 192. The main body 191 accommodates the toner, and is disposed on one side of the developing unit 4 in the longitudinal direction D2. The transport unit 192 transports the toner of the main body unit 191 toward the developing unit 4 by a known mechanism such as a screw mechanism. The transport unit 192 has a toner discharge port 193. The toner discharge port 193 is provided at a position from the one end portion of the developing unit 4 and is connected to the toner introduction port 42 of the developing unit 4. That is, the toner discharge port 193 and the toner introduction port 42 are connected to each other to form the connecting portion 9. In the toner container 19, the toner stored in the main body 191 is transported to the toner discharge port 193 by the transport unit 192 and introduced into the developing unit 4 through the connecting unit 9. The toner container 19 may contain waste toner collected by the cleaning unit 7 in addition to the toner supplied to the developing unit 4.

一次転写ローラー６は、感光体ドラム２に形成されたトナー像を中間転写ベルト１２の下面に転写する。中間転写ベルト１２は、画像形成ユニット１１の感光体ドラム２の上方を進行し、感光体ドラム２に形成された各色のトナー像が順次重ね合わせて転写されるものである。 The primary transfer roller 6 transfers the toner image formed on the photosensitive drum 2 to the lower surface of the intermediate transfer belt 12. The intermediate transfer belt 12 travels above the photosensitive drum 2 of the image forming unit 11, and the toner images of the respective colors formed on the photosensitive drum 2 are sequentially superimposed and transferred.

そして、中間転写ベルト１２のトナー像は、二次転写ローラー１４により、給紙カセット１７から搬送経路１８を経て搬送されるシートに転写される。その後、前記シートに転写されたトナー像は、定着装置１５で加熱されて前記シートに溶融定着する。 The toner image on the intermediate transfer belt 12 is transferred by the secondary transfer roller 14 to a sheet conveyed from the paper feed cassette 17 via the conveyance path 18. Thereafter, the toner image transferred to the sheet is heated and fixed on the sheet by the fixing device 15.

クリーニング部７は、一次転写ローラー６による前記トナー像の中間転写ベルト１２への転写後の感光体ドラム２の表面から残存トナーを除去するクリーニングローラー７１を有する。 The cleaning unit 7 includes a cleaning roller 71 that removes residual toner from the surface of the photosensitive drum 2 after the toner image is transferred to the intermediate transfer belt 12 by the primary transfer roller 6.

除電部５は、感光体ドラム２に形成された前記トナー像を中間転写ベルト１２に転写した後、感光体ドラム２の表面から残留電位を除電光Ｌ１の照射により除去するものである。除電部５は、感光体ドラム２の外周面における中間転写ベルト１２に接する転写位置と、クリーニング部７との間の除電領域２０に除電光Ｌ１を照射する。図３に示すように、除電部５は、ＬＥＤ等の光源５１、及び感光体ドラム２の軸方向に延びる長尺の導光部材５２を有する。 The neutralizing unit 5 transfers the toner image formed on the photosensitive drum 2 to the intermediate transfer belt 12, and then removes the residual potential from the surface of the photosensitive drum 2 by irradiation with the neutralizing light L1. The neutralization unit 5 irradiates the neutralization region 20 between the transfer position in contact with the intermediate transfer belt 12 on the outer peripheral surface of the photosensitive drum 2 and the cleaning unit 7 with the neutralization light L1. As shown in FIG. 3, the static elimination unit 5 includes a light source 51 such as an LED and a long light guide member 52 extending in the axial direction of the photosensitive drum 2.

なお、除電部５は、保持部材８を介してクリーニング部７に固定されている。そのため、除電部５は、進行方向Ｄ１の下流側の画像形成ユニット１１の現像部４に隣接した位置に配置されている。 The static elimination unit 5 is fixed to the cleaning unit 7 via a holding member 8. For this reason, the static eliminating unit 5 is disposed at a position adjacent to the developing unit 4 of the image forming unit 11 on the downstream side in the traveling direction D1.

光源５１は、感光体ドラム２の除電に用いられる光を出射する。光源５１は、光の出射面５１１が導光部材５２の一端面５２１に対向する向きで配置されている。ここで、一端面５２１は、導光部材５２の長手方向Ｄ２におけるトナーコンテナ１９側の一端である。即ち、光源５１は、導光部材５２における連結部９に近い側の一端に向けて光を出射する。 The light source 51 emits light used for neutralizing the photosensitive drum 2. The light source 51 is arranged such that the light emission surface 511 faces the one end surface 521 of the light guide member 52. Here, the one end surface 521 is one end of the light guide member 52 on the toner container 19 side in the longitudinal direction D2. That is, the light source 51 emits light toward one end of the light guide member 52 on the side close to the connecting portion 9.

光源５１から出射される光は、導光部材５２の長手方向Ｄ２の一端面５２１に入射する。そして、導光部材５２では、一端面５２１から入射される光が反射を繰り返して長手方向Ｄ２の他端面５２２に向けて導かれ、感光体ドラム２に向けて除電光が出射される。 The light emitted from the light source 51 enters the one end surface 521 of the light guide member 52 in the longitudinal direction D2. In the light guide member 52, light incident from the one end surface 521 is repeatedly reflected and guided toward the other end surface 522 in the longitudinal direction D 2, and discharge light is emitted toward the photosensitive drum 2.

なお、本実施形態では、導光部材５２の一端面５２１に対向して光源５１が設けられている場合を例に挙げて説明するが、導光部材５２の一端面５２１に対向する光源５１に加えて他端面５２２に対向して光源を設け、一端面５２１及び他端面５２２の両方から光が入射する構成も他の実施形態として考えられる。この場合、一端面５２１側の光源は、他端面５２２よりも強度の高い光を出射するものであることが好ましい。 In the present embodiment, a case where the light source 51 is provided facing the one end surface 521 of the light guide member 52 will be described as an example, but the light source 51 facing the one end surface 521 of the light guide member 52 is used. In addition, a configuration in which a light source is provided facing the other end surface 522 and light is incident from both the one end surface 521 and the other end surface 522 is also conceivable as another embodiment. In this case, the light source on the one end surface 521 side preferably emits light having a higher intensity than the other end surface 522.

図４〜図６に示すように、導光部材５２は、基部５２３及びレンズ部５２４を有している。導光部材５２は、例えば樹脂等の材料により、感光体ドラム２よりも長手方向Ｄ２の寸法が大きい断面略Ｄ字形状に形成されている。 As illustrated in FIGS. 4 to 6, the light guide member 52 includes a base portion 523 and a lens portion 524. The light guide member 52 is formed of a material such as resin, for example, in a substantially D-shaped cross section having a dimension in the longitudinal direction D2 larger than that of the photosensitive drum 2.

基部５２３は、導光部材５２における中間転写ベルト１２の進行方向Ｄ１の下流側に形成されている。基部５２３は、一定の厚みを有する部分であり、図５に示す導光部材５２における仮想線Ｂの右側の部分に相当する。基部５２３は、進行方向Ｄ１の下流側に長手方向Ｄ２に延びる長矩形状の傾斜面５２５を有する。 The base 523 is formed on the downstream side of the light guide member 52 in the traveling direction D1 of the intermediate transfer belt 12. The base 523 is a portion having a certain thickness, and corresponds to a portion on the right side of the virtual line B in the light guide member 52 shown in FIG. The base 523 has a long rectangular inclined surface 525 extending in the longitudinal direction D2 on the downstream side in the traveling direction D1.

傾斜面５２５は、上下方向Ｄ３に対して進行方向Ｄ１の下流側に傾斜している（図２参照）。傾斜面５２５の上下方向Ｄ３に対する傾斜角度は、例えば５°以上１５°以下である。また、傾斜面５２５には、導光部材５２の内部を長手方向Ｄ２に沿って進行する光を感光体ドラム２の除電領域２０に向けて反射する複数の凹部５２７が形成されている。導光部材５２では、複数の凹部５２７が等間隔で形成されている。 The inclined surface 525 is inclined to the downstream side in the traveling direction D1 with respect to the vertical direction D3 (see FIG. 2). The inclination angle of the inclined surface 525 with respect to the vertical direction D3 is, for example, not less than 5 ° and not more than 15 °. In addition, the inclined surface 525 is formed with a plurality of recesses 527 that reflect the light traveling in the light guide member 52 along the longitudinal direction D 2 toward the charge removal region 20 of the photosensitive drum 2. In the light guide member 52, a plurality of recesses 527 are formed at equal intervals.

凹部５２７は、長手方向Ｄ２に沿う断面が一様なＶ字状に形成され、底部から開口部に向かうに従い拡開している。そして、凹部５２７では、その表面５２８において導光部材５２の内部を進行する光を反射し、導光部材５２の内部を進行する光を進行方向Ｄ１の上流側に向けたものとする。なお、凹部５２７の断面形状が半円形等である他の実施形態も考えられる。 The recess 527 is formed in a V-shaped cross section along the longitudinal direction D2, and expands from the bottom toward the opening. In the concave portion 527, light traveling inside the light guide member 52 is reflected on the surface 528, and light traveling inside the light guide member 52 is directed upstream in the traveling direction D1. Other embodiments in which the cross-sectional shape of the recess 527 is semicircular or the like are also conceivable.

レンズ部５２４は、導光部材５２における基部５２３に対して進行方向Ｄ１の上流側に形成されている。なお、レンズ部５２４は、図５に示す導光部材５２における仮想線Ｂの左側の部分に相当する。 The lens portion 524 is formed on the upstream side in the traveling direction D1 with respect to the base portion 523 of the light guide member 52. The lens portion 524 corresponds to the left portion of the imaginary line B in the light guide member 52 shown in FIG.

レンズ部５２４における長手方向Ｄ２に直交する方向に沿う断面の形状は、一様に略半円状である。レンズ部５２４は、複数の凹部５２７で反射した光を集光すると共に除電光Ｌ１として除電領域２０に照射する。これにより、導光部材５２は、長手方向Ｄ２に沿った一様な光を除電光Ｌ１として除電領域２０に向けて出射する。 The shape of the cross section along the direction orthogonal to the longitudinal direction D2 in the lens portion 524 is uniformly substantially semicircular. The lens unit 524 collects the light reflected by the plurality of concave portions 527 and irradiates the static elimination region 20 as the static elimination light L1. Thereby, the light guide member 52 emits uniform light along the longitudinal direction D2 toward the charge removal region 20 as charge removal light L1.

レンズ部５２４の光軸Ｌ０の方向は、基部５２３の傾斜面５２５に直交又は略直交する方向である。ここで、略直交とは、直交方向に対する傾斜角度が±５°の範囲を意味する。そのため、レンズ部５２４の光軸Ｌ０は、傾斜面５２５の傾斜角度に対応し、中間転写ベルト１２の進行方向Ｄ１に対して、例えば５°以上１５°以下で上方に向けて傾斜している。即ち、レンズ部５２４からは、中間転写ベルト１２の進行方向Ｄ１に対して若干上向きに除電光Ｌ１が出射される。 The direction of the optical axis L0 of the lens portion 524 is a direction orthogonal or substantially orthogonal to the inclined surface 525 of the base portion 523. Here, “substantially orthogonal” means a range in which the inclination angle with respect to the orthogonal direction is ± 5 °. Therefore, the optical axis L0 of the lens unit 524 corresponds to the inclination angle of the inclined surface 525, and is inclined upward at, for example, 5 ° to 15 ° with respect to the traveling direction D1 of the intermediate transfer belt 12. That is, the neutralizing light L1 is emitted from the lens portion 524 slightly upward with respect to the traveling direction D1 of the intermediate transfer belt 12.

光軸Ｌ０は除電領域２０と交差している。即ち、中間転写ベルト１２の進行方向Ｄ１に対するレンズ部５２４の光軸Ｌ０の傾斜角度は、光軸Ｌ０が除電領域２０から外れない角度に設定されている。そのため、レンズ部５２４から除電領域２０に向けて出射される除電光Ｌ１のうち、光軸Ｌ０周辺の最も強度の大きな部分の光が、除電光Ｌ１として除電領域２０に直接照射される。これにより、感光体ドラム２の除電領域２０に照射される除電光Ｌ１の強度が十分に確保される。 The optical axis L0 intersects with the static elimination region 20. That is, the inclination angle of the optical axis L0 of the lens unit 524 with respect to the traveling direction D1 of the intermediate transfer belt 12 is set to an angle at which the optical axis L0 does not deviate from the charge removal region 20. Therefore, among the static elimination light L1 emitted toward the static elimination area 20 from the lens part 524, the light of the strongest part around the optical axis L0 is directly irradiated to the static elimination area 20 as the static elimination light L1. Thereby, the intensity | strength of the static elimination light L1 irradiated to the static elimination area | region 20 of the photosensitive drum 2 is fully ensured.

なお、レンズ部５２４の形状として、断面半円状に限らず、集光作用を有する他の形状を採用することも考えられる。また、導光部材５２が、断面が円形又は楕円形の部材であることも考えられる。 It should be noted that the shape of the lens portion 524 is not limited to a semicircular cross section, and other shapes having a condensing function may be employed. It is also conceivable that the light guide member 52 is a member having a circular or elliptical cross section.

図７は、感光体ドラム２の除電領域２０に照射される除電光Ｌ１の光量と、除電光Ｌ１を照射した後の感光体ドラムの除電領域２０の表面電位との関係を示すグラフである。 FIG. 7 is a graph showing the relationship between the amount of the neutralizing light L1 irradiated to the neutralizing region 20 of the photosensitive drum 2 and the surface potential of the neutralizing region 20 of the photosensitive drum after the neutralizing light L1 is irradiated.

図７に示すように、感光体ドラム２の除電領域２０に照射される除電光Ｌ１の光量は、除電光Ｌ１を照射した後の感光体ドラム２の除電領域２０の表面電位に影響を与える。具体的には、除電領域２０に照射する除電光Ｌ１の光量が小さいと、感光体ドラム２の残留電位を十分に低減できず表面電位の低下が十分に図れない。そして、感光体ドラム２の除電が不十分であると、ドラムゴースト等による印刷画質の低下が生じ得る。このような印刷画質の低下が生じ難い表面電位とするために必要な光量を、以下、最低除電光量ＱＮ１と称する。 As shown in FIG. 7, the amount of the neutralizing light L 1 applied to the static elimination region 20 of the photosensitive drum 2 affects the surface potential of the static elimination region 20 of the photosensitive drum 2 after the static elimination light L 1 is irradiated. Specifically, if the amount of the neutralizing light L1 applied to the neutralizing region 20 is small, the residual potential of the photosensitive drum 2 cannot be sufficiently reduced and the surface potential cannot be sufficiently lowered. If the charge removal of the photosensitive drum 2 is insufficient, the print image quality may be deteriorated due to drum ghost or the like. The amount of light necessary to obtain a surface potential that is unlikely to cause a decrease in print image quality is hereinafter referred to as a minimum charge removal amount QN1.

一方、導光部材５２では、レンズ部５２４に汚れが生じると、汚れにより除電光Ｌ１が減衰され、除電光Ｌ１の光量が低下する。そして、除電部５により感光体ドラム２に照射される除電光Ｌ１の光量が最低除電光量ＱＮ１を下回ると、感光体ドラム２の除電不足により印刷画質が低下し得る。 On the other hand, in the light guide member 52, when the lens portion 524 is soiled, the charge removal light L1 is attenuated by the stain, and the light amount of the charge removal light L1 is reduced. When the amount of the neutralizing light L1 applied to the photosensitive drum 2 by the neutralizing unit 5 is less than the minimum neutralizing light amount QN1, the print image quality may be deteriorated due to insufficient neutralization of the photosensitive drum 2.

導光部材５２に汚れが生じる主な原因としては、装置内を飛散するトナーが考えられる。導光部材５２には、例えばトナーコンテナ１９のトナー排出口１９３と現像部４のトナー導入口４２との連結部９、進行方向Ｄ１の下流側の画像形成ユニット１１における感光体ドラム２と現像部４との隙間、中間転写ベルト１２等から飛散するトナーが付着し得る。画像形成装置１０のように現像部４の側方にトナーコンテナ１９が配置される場合、連結部９から飛散するトナーが導光部材５２のレンズ部５２４に付着しやすい。そのため、導光部材５２のトナー汚染度は、連結部９に近い領域が連結部９から遠い領域に比べて高くなる。 As a main cause of the contamination of the light guide member 52, toner scattered in the apparatus can be considered. The light guide member 52 includes, for example, a connecting portion 9 between the toner discharge port 193 of the toner container 19 and the toner introduction port 42 of the developing unit 4, and the photosensitive drum 2 and the developing unit in the image forming unit 11 downstream in the traveling direction D1. 4, toner scattered from the intermediate transfer belt 12 and the like may adhere. When the toner container 19 is disposed on the side of the developing unit 4 as in the image forming apparatus 10, the toner scattered from the connecting unit 9 tends to adhere to the lens unit 524 of the light guide member 52. Therefore, the degree of toner contamination of the light guide member 52 is higher in the region near the connecting portion 9 than in the region far from the connecting portion 9.

導光部材５２における連結部９に近い領域は、本発明の「第２領域よりもトナー汚染度が高くなることが予想される領域」である第１領域の一例に相当する。具体的には、図３の導光部材５２では、レンズ部５２４における長手方向Ｄ２の光源５１に対向する一端面５２１側の部分が第１領域５３１である。 The region near the connecting portion 9 in the light guide member 52 corresponds to an example of a first region that is a “region where the degree of toner contamination is expected to be higher than that in the second region” of the present invention. Specifically, in the light guide member 52 of FIG. 3, the portion on the one end face 521 side that faces the light source 51 in the longitudinal direction D 2 in the lens portion 524 is the first region 531.

導光部材５２における連結部９に遠い領域は、本発明の第２領域の一例に相当する。具体的には、図３の導光部材５２では、レンズ部５２４における長手方向Ｄ２の一端面５２１とは反対の他端面５２２側の部分が第２領域５３２である。 The region far from the connecting portion 9 in the light guide member 52 corresponds to an example of the second region of the present invention. Specifically, in the light guide member 52 of FIG. 3, the portion on the other end surface 522 side opposite to the one end surface 521 in the longitudinal direction D2 in the lens portion 524 is the second region 532.

これに対し、画像形成装置１０の除電部５では、光源５１が導光部材５２における連結部９に近い側の一端面５２１に向けて光を出射し、導光部材５２の傾斜面５２５における複数の凹部５２７の間隔を等間隔としている。そのため、除電部５では、導光部材５２の一端面５２１に光源５１から光を入射させた場合、導光部材５２から出射される除電光Ｌ１の光量は、光源５１からの距離に依存する。 On the other hand, in the charge removal unit 5 of the image forming apparatus 10, the light source 51 emits light toward the one end surface 521 of the light guide member 52 on the side close to the connecting portion 9, and a plurality of light sources 51 on the inclined surface 525 of the light guide member 52. The intervals of the recesses 527 are equal. Therefore, in the static elimination unit 5, when light from the light source 51 is incident on the one end surface 521 of the light guide member 52, the light amount of the static elimination light L 1 emitted from the light guide member 52 depends on the distance from the light source 51.

具体的には、図８に一例を示すように、導光部材５２からの除電光Ｌ１の光量は、導光部材５２の光源５１に近い部分が大きくなり、光源５１から離れるほど小さくなる傾向を有する。換言すれば、導光部材５２からの除電光Ｌ１の光量は、長手方向Ｄ２において第１領域５３１に近づくに従って光量が大きくなる傾向の光量分布を有する。このように除電部５では、連結部９に近い第１領域５３１から出射される除電光の光量が、連結部９から遠い第２領域５３２から出射される除電光の光量よりも大きい。そのため、除電部５では、第２領域５３２よりもトナー汚染度が高くなることが予想される第１領域５３１において、第２領域５３２によりも大きい光量の除電光Ｌ１を出射する。これにより、除電部５では、導光部材５２から出射された除電光Ｌ１が付着トナーにより減衰され、除電光Ｌ１の光量が低下したとしても、除電光Ｌ１の光量を最低除電光量ＱＮ１以上に確保することが可能となる。その結果、画像形成装置１０では、感光体ドラム２の除電不足により印刷画質の低下を抑制できる。 Specifically, as shown in an example in FIG. 8, the light amount of the charge removal light L 1 from the light guide member 52 tends to increase as the portion near the light source 51 of the light guide member 52 increases and decreases as the distance from the light source 51 increases. Have. In other words, the light quantity of the static elimination light L1 from the light guide member 52 has a light quantity distribution in which the light quantity tends to increase as it approaches the first region 531 in the longitudinal direction D2. As described above, in the static elimination unit 5, the amount of static elimination light emitted from the first region 531 close to the connecting portion 9 is larger than the amount of static elimination light emitted from the second region 532 far from the coupling portion 9. For this reason, the charge removal unit 5 emits a larger amount of charge removal light L 1 than in the second area 532 in the first area 531 where the degree of toner contamination is expected to be higher than that in the second area 532. Thereby, in the static elimination part 5, even if the static elimination light L1 radiate | emitted from the light guide member 52 is attenuate | damped by adhesion toner and the light quantity of static elimination light L1 falls, the light quantity of static elimination light L1 is ensured more than the minimum static elimination light quantity QN1. It becomes possible to do. As a result, in the image forming apparatus 10, it is possible to suppress a decrease in print image quality due to insufficient neutralization of the photosensitive drum 2.

なお、導光部材５２の第１領域５３１での除電光Ｌ１の光量ＱＮ２は、例えば最低除電光量ＱＮ１の２倍以上、第２領域５３２での除電光Ｌ１の光量ＱＮ３の１．２倍以上１．６倍以下とされる。このような範囲に第１領域５３１での除電光Ｌ１の光量ＱＮ２を設定することで、出射強度が大きい高価な光源５１を用いることなく、導光部材５２の第１領域５３１での除電光Ｌ１の光量ＱＮ２を最低除電光量ＱＮ１以上に確保することが容易となる。また、導光部材５２の第２領域５３２での除電光Ｌ１の光量ＱＮ３が必要以上に低下してしまうことも抑制される。 Note that the light quantity QN2 of the static elimination light L1 in the first region 531 of the light guide member 52 is, for example, not less than twice the minimum static elimination light quantity QN1, and 1.2 times or more of the light quantity QN3 of the static elimination light L1 in the second area 532. .6 times or less. By setting the light quantity QN2 of the static elimination light L1 in the first area 531 within such a range, the static elimination light L1 in the first area 531 of the light guide member 52 can be used without using the expensive light source 51 having a high emission intensity. It is easy to secure the amount of light QN2 to be equal to or greater than the minimum amount of light QN1. Moreover, it is also suppressed that the light quantity QN3 of the static elimination light L1 in the second region 532 of the light guide member 52 is unnecessarily lowered.

このような効果は、除電部５において、導光部材５２における連結部９に近い側の一端面５２１に向けて光源５１からの光を出射させ、導光部材５２の傾斜面５２５における複数の凹部５２７の間隔を等間隔とすることで得られる。そのため、画像形成装置１０では、トナー汚染による感光体ドラム２の除電不足を抑制するために、装置の大型化やコストアップを招来することもない。 Such an effect is that, in the static elimination unit 5, the light from the light source 51 is emitted toward the one end surface 521 on the side of the light guide member 52 close to the connecting portion 9, and a plurality of concave portions on the inclined surface 525 of the light guide member 52. It is obtained by making the interval of 527 equal. Therefore, the image forming apparatus 10 does not cause an increase in size or cost of the apparatus in order to suppress insufficient charge removal of the photosensitive drum 2 due to toner contamination.

従って、画像形成装置１０は、装置の大型化やコストアップを抑制しつつ、感光体ドラム２の除電不足に起因する印刷画質の低下を抑制できる。 Therefore, the image forming apparatus 10 can suppress a decrease in print image quality due to insufficient neutralization of the photosensitive drum 2 while suppressing an increase in size and cost of the apparatus.

［他の実施形態］
以下、図９〜図１５を参照し、本発明の他の実施形態を説明する。なお、図９〜図１５では、トナーコンテナのトナー排出口と、現像部のトナー導入口との連結部が図示されていないが、以下の説明での連結部９は、図３等に示される第１の実施形態の連結部９と同様なものを意味する。 [Other Embodiments]
Hereinafter, another embodiment of the present invention will be described with reference to FIGS. 9 to 15 do not show the connecting portion between the toner discharge port of the toner container and the toner introducing port of the developing unit, but the connecting portion 9 in the following description is shown in FIG. The same thing as the connection part 9 of 1st Embodiment is meant.

図９〜図１２に示す除電部５Ａ〜５Ｄでは、第１領域５３１における長手方向Ｄ２の単位長さ当たりの複数の凹部５２７Ａ〜５２７Ｄの総内面積である単位凹面積が、第２領域５３２よりも大きい。即ち、除電部５Ａ〜５Ｄでは、連結部９に近いトナー汚染度が高いことが予想される第１領域５３１における複数の凹部の５２７Ａ〜５２７Ｄによる総反射面積が、連結部９から遠くトナー汚染度が第１領域５３１よりも低いことが予想される第２領域５３２よりも大きくされている。 In the static eliminators 5 A to 5 D illustrated in FIGS. 9 to 12, the unit concave area that is the total inner area of the plurality of concave portions 527 A to 527 D per unit length in the longitudinal direction D 2 in the first region 531 is greater than the second region 532. Is also big. In other words, in the charge removal units 5A to 5D, the total reflection area of the plurality of concave portions 527A to 527D in the first region 531 where the degree of toner contamination close to the connection unit 9 is expected to be high is far from the connection unit 9. Is larger than the second region 532, which is expected to be lower than the first region 531.

例えば、図９に示す除電部５Ａは、導光部材５２Ａの複数の凹部５２７Ａの深さが、光源５１及び連結部９に近い第１領域５３１のほうが、光源５１及び連結部９から遠い第２領域５３２よりも大きい。また、複数の凹部５２７Ａの深さは、長手方向Ｄ２に沿った方向において、光源５１から離れるに従い連続的に小さくなっている。 For example, in the static eliminator 5 A shown in FIG. 9, the depth of the plurality of concave portions 527 A of the light guide member 52 A is second in the first region 531 closer to the light source 51 and the connecting portion 9 and farther from the light source 51 and the connecting portion 9. Larger than region 532. Further, the depths of the plurality of recesses 527A are continuously reduced as the distance from the light source 51 increases in the direction along the longitudinal direction D2.

図１０に示す除電部５Ｂは、図９に示す除電部５Ａと同様に、複数の凹部５２７Ｂの深さが、光源５１及び連結部９に近い第１領域５３１のほうが、光源５１及び連結部９から遠い第２領域５３２よりも大きい。また、図１０に示す複数の凹部５２７Ｂの深さは、長手方向Ｄ２に沿った方向において、光源５１からから離れるに従い段階的に小さくなる。 10, in the first region 531 where the depth of the plurality of recesses 527B is closer to the light source 51 and the connection portion 9, the light source 51 and the connection portion 9 are similar to the charge removal portion 5 A illustrated in FIG. 9. It is larger than the second region 532 far from the center. Further, the depths of the plurality of recesses 527B shown in FIG. 10 gradually decrease as the distance from the light source 51 increases in the direction along the longitudinal direction D2.

図１１に示す除電部５Ｃは、導光部材５２Ｃの複数の凹部５２７Ｃの長さが、光源５１及び連結部９に近い第１領域５３１のほうが、光源５１及び連結部９から遠い第２領域５３２よりも大きい。また、複数の凹部５２７Ｃの長さは、光源５１から離れるに従い連続的に小さくなる。なお、複数の凹部５２７Ｃの長さは、長手方向Ｄ２に沿った方向において、トナーコンテナ１９から離れるに従い段階的に小さくなっていてもよい。 11C, the length of the plurality of concave portions 527C of the light guide member 52C is such that the first region 531 closer to the light source 51 and the connecting portion 9 is the second region 532 farther from the light source 51 and the connecting portion 9. Bigger than. In addition, the length of the plurality of recesses 527C continuously decreases as the distance from the light source 51 increases. Note that the lengths of the plurality of recesses 527C may gradually decrease in the direction along the longitudinal direction D2 as the distance from the toner container 19 increases.

図１２に示す除電部５Ｄは、導光部材５２Ｄの複数の凹部５２７Ｃの間隔が、光源５１及び連結部９に近い第１領域５３１のほうが、光源５１及び連結部９から遠い第２領域５３２よりも小さい。また、複数の凹部５２７Ｃの間隔は、長手方向Ｄ２に沿った方向において、光源５１から離れるに従い連続的に大きくなる。 In the static eliminator 5D shown in FIG. 12, the distance between the plurality of recesses 527C of the light guide member 52D is greater in the first region 531 closer to the light source 51 and the connecting portion 9 than in the second region 532 farther from the light source 51 and the connecting portion 9. Is also small. Further, the interval between the plurality of recesses 527C continuously increases as the distance from the light source 51 increases in the direction along the longitudinal direction D2.

図９〜図１２に示す除電部５Ａ〜５Ｄのように、光源５１及び連結部９に近い第１領域５３１では、連結部９から遠い第２領域５３２よりも、長手方向Ｄ２の単位長さ当たりの総反射面積が大きい。そのため、第１領域５３１での複数の凹部５２７Ａ〜５２７Ｃによる感光体ドラム２に向けた方向への反射光量が、第２領域５３２での前記反射光量よりも大きくなる。これにより、連結部９に近いトナー汚染度の高いことが予想される第１領域５３１での除電光Ｌ１の光量が、連結部９から遠い第２領域５３２よりも大きくされる。その結果、除電部５Ａ〜５Ｄでは、導光部材５２Ａ〜５２Ｄにおける連結部９に近い一端面５２１に光源５１からの光を入射させることに加え、前記単位凹面積を第２領域５３２よりも大きくすることで、第１領域５３１での除電光Ｌ１の光量ＱＮ２を最低除電光量ＱＮ１の２倍以上に確保することが容易となる。 In the first region 531 close to the light source 51 and the connecting portion 9 as in the charge eliminating portions 5A to 5D shown in FIGS. 9 to 12, per unit length in the longitudinal direction D2 than the second region 532 far from the connecting portion 9. The total reflection area is large. Therefore, the amount of reflected light in the direction toward the photosensitive drum 2 by the plurality of recesses 527A to 527C in the first region 531 is larger than the amount of reflected light in the second region 532. As a result, the amount of the charge removal light L1 in the first region 531 that is expected to have a high degree of toner contamination near the connecting portion 9 is made larger than that in the second region 532 far from the connecting portion 9. As a result, in the static eliminators 5A to 5D, in addition to making the light from the light source 51 incident on one end surface 521 of the light guide members 52A to 52D near the connecting portion 9, the unit concave area is made larger than that of the second region 532. By doing so, it becomes easy to secure the light quantity QN2 of the static elimination light L1 in the first region 531 at least twice the minimum static elimination light quantity QN1.

また、図１３に示す除電部５Ｅは、導光部材５２Ｅにおける連結部９に近い一端面５２１側に光源５１が配置される一方で、連結部９から遠い他端面５２２に反射部５２６Ｅが設けられたものである。 Further, in the static elimination unit 5E illustrated in FIG. 13, the light source 51 is disposed on the one end surface 521 side close to the connection unit 9 in the light guide member 52E, and the reflection unit 526E is provided on the other end surface 522 far from the connection unit 9. It is a thing.

反射部５２６Ｅは、導光部材５２Ｅの内部を他端面５２２に向けて進行する光を反射し、一端面５２１に向けて進行させる。反射部５２６Ｅは、例えばアルミ蒸着フィルム、白色フィルム等の反射フィルムの貼着、白色塗料の塗工により形成される。 The reflection portion 526E reflects the light traveling toward the other end surface 522 inside the light guide member 52E and proceeds toward the one end surface 521. The reflection part 526E is formed by sticking a reflective film such as an aluminum vapor deposition film or a white film or applying a white paint, for example.

第１領域５３１及び第２領域５３２では、複数の凹部５２７Ｅが等間隔に設けられている。これに対し、第１領域５３１と第２領域５３２との間に設けられた中間領域５３３では、複数の凹部５２７Ｅが第１領域５３１側から第２領域５３２側に向かうに従い小さくなる。そして、複数の凹部５２７Ｅの間隔は、図１２に示す除電部５Ｄとは逆に、光源５１及び連結部９に近い第１領域５３１のほうが連結部９から遠い第２領域５３２よりも大きい。また、中間領域５３３では、複数の凹部５２７Ｅの間隔が、第１領域５３１より小さく、第２領域５３２よりも大きい。即ち、導光部材５２Ｅでは、複数の凹部５２７Ｅの間隔が、第２領域５３２、中間領域５３３、及び第１領域５３１の順に小さく、この順で前記単位凹面積ひいては前記総反射面積が大きくなる。また、導光部材５２Ｅでは、中間領域５３３における複数の凹部５２７Ｅが、長手方向Ｄ２において第１領域５３１から第２領域５３２に向かうに従い前記単位凹面積が増大する。そして、中間領域５３３における長手方向Ｄ２の前記単位凹面積の変化率は、第１領域５３１及び第２領域５３２における前記単位凹面積の長手方向Ｄ２の変化率よりも大きい。 In the first region 531 and the second region 532, a plurality of recesses 527E are provided at equal intervals. On the other hand, in the intermediate region 533 provided between the first region 531 and the second region 532, the plurality of concave portions 527E become smaller from the first region 531 side toward the second region 532 side. And the space | interval of the some recessed part 527E is larger than the 2nd area | region 532 far from the connection part 9 in the 1st area | region 531 near the light source 51 and the connection part 9, contrary to the static elimination part 5D shown in FIG. In the intermediate region 533, the interval between the plurality of recesses 527 E is smaller than the first region 531 and larger than the second region 532. In other words, in the light guide member 52E, the interval between the plurality of recesses 527E decreases in the order of the second region 532, the intermediate region 533, and the first region 531. In this order, the unit recess area and thus the total reflection area increase. In the light guide member 52E, the unit concave area increases as the plurality of concave portions 527E in the intermediate region 533 move from the first region 531 to the second region 532 in the longitudinal direction D2. The rate of change of the unit concave area in the longitudinal direction D2 in the intermediate region 533 is greater than the rate of change in the longitudinal direction D2 of the unit concave area in the first region 531 and the second region 532.

除電部５Ｅでは、第１領域５３１からの除電光Ｌ１の光量が光源５１に近いことで確保される。一方、第２領域５３２からの除電光Ｌ１の光量は、複数の凹部５２７Ｅの間隔を小さくすることと、反射部５２６での戻り光を利用することで確保できる。そのため、除電部５Ｅでは、第２領域５３２側からの除電光Ｌ１が著しく小さくなること、即ち最低除電光量ＱＮ１よりも小さくなることを抑制できる。 In the charge removal unit 5 E, the amount of the charge removal light L 1 from the first region 531 is ensured by being close to the light source 51. On the other hand, the light quantity of the static elimination light L1 from the second region 532 can be ensured by reducing the interval between the plurality of recesses 527E and using the return light from the reflection part 526. Therefore, in the static elimination part 5E, it can suppress that the static elimination light L1 from the 2nd area | region 532 side becomes remarkably small, ie, smaller than the minimum static elimination light quantity QN1.

また、図１４に示す除電部５Ｆは、複数の凹部のうちの光源５１及び連結部９に近い第１領域５３１に形成される凹部５２７Ｆが、導光部材５２Ｆの短手方向Ｄ４に対する傾斜角度が異なる第１反射面５４Ｆ及び第２反射面５５Ｆを有する。なお、図面上は省略されているが、光源５１及び連結部９から遠い第２領域５３２の凹部は、凹部５２７Ｆと深さ及び長さが同じで、図６等に示された凹部５２７等と同様に、第１反射面５４Ｆと同じ傾斜角度の反射面のみで形成されたものである。 Further, in the charge removal portion 5F shown in FIG. 14, the concave portion 527F formed in the first region 531 near the light source 51 and the connecting portion 9 among the plurality of concave portions has an inclination angle with respect to the short direction D4 of the light guide member 52F. The first reflection surface 54F and the second reflection surface 55F are different. Although not shown in the drawing, the concave portion of the second region 532 far from the light source 51 and the connecting portion 9 has the same depth and length as the concave portion 527F, and the concave portion 527 shown in FIG. Similarly, the first reflecting surface 54F is formed only by a reflecting surface having the same inclination angle.

第１反射面５４Ｆは、凹部５２７Ｆの底部側領域５６Ｆを規定する傾斜面である。第２反射面５５Ｆは、凹部５２７Ｆの開口部側領域５７Ｆを規定し、第１反射面５３Ｆよりも導光部材５２Ｆの短手方向Ｄ４に対する傾斜角度が大きい傾斜面である。即ち、凹部５２７Ｆは、底部から開口部に向けて拡開し、その拡開率が底部側領域５６Ｆに比べて開口部側領域５７Ｆのほうが大きい。そのため、導光部材５２Ｆでは、第１反射面５３Ｆのみにより形成される凹部に比べて、開口部側での拡開率が大きいことにより凹部５２７Ｆの前記単位凹面積ひいては前記総反射面積が大きく確保される。これにより、導光部材５２Ｆでは、連結部９に近いトナー汚染度の高いと予想される第１領域５３１での除電光Ｌ１の光量が、連結部９から遠い第２領域５３２よりも大きくされる。その結果、導光部材５２Ｆでは、第１領域５３１での除電光Ｌ１の光量ＱＮ２を最低除電光量ＱＮ１の２倍以上に確保することが容易となる。 The first reflecting surface 54F is an inclined surface that defines the bottom side region 56F of the recess 527F. The second reflection surface 55F is an inclined surface that defines the opening side region 57F of the recess 527F and has a larger inclination angle with respect to the short direction D4 of the light guide member 52F than the first reflection surface 53F. That is, the concave portion 527F expands from the bottom toward the opening, and the expansion rate of the opening side region 57F is larger than that of the bottom side region 56F. Therefore, in the light guide member 52F, the expansion ratio on the opening side is larger than that of the recess formed only by the first reflecting surface 53F, so that the unit recess area of the recess 527F and thus the total reflection area are ensured to be large. Is done. As a result, in the light guide member 52F, the amount of charge removal light L1 in the first region 531 that is expected to have a high degree of toner contamination near the connecting portion 9 is made larger than that in the second region 532 far from the connecting portion 9. . As a result, in the light guide member 52F, it becomes easy to secure the light quantity QN2 of the static elimination light L1 in the first region 531 at least twice the minimum static elimination light quantity QN1.

なお、図１５に示す除電部５Ｇの導光部材５２Ｆように、光源５１及び連結部９に近い第１領域５３１の凹部５２７Ｇとして、図１４に示される傾斜面とされた第２反射面５５Ｆに代えて、曲面とされた第２反射面５９Ｇを採用してもよい。この第２反射面５９Ｇによっても凹部５２７Ｇの前記単位凹面積ひいては前記総反射面積を大きく確保できるため、除電部５Ｇは、図１４に示す除電部５Ｆと同様の効果を奏する。 In addition, as the light guide member 52F of the static elimination part 5G shown in FIG. 15, as the recessed part 527G of the 1st area | region 531 near the light source 51 and the connection part 9, it is on the 2nd reflective surface 55F made into the inclined surface shown in FIG. Instead, the curved second reflection surface 59G may be employed. The second reflection surface 59G can also secure the unit recess area of the recess 527G and thus the total reflection area, so that the charge removal portion 5G has the same effect as the charge removal portion 5F shown in FIG.

また、第１の実施形態及び他の実施形態では、トナーコンテナが現像部の一端側に配置され、導光部材の長手方向におけるトナーコンテナと同じ側に光源が配置されていたが、本発明はトナーコンテナ及び／又は光源が前記実施形態とは異なる位置に設けられる画像形成装置にも適用できる。即ち、本発明は、導光部材におけるトナー汚染度が高いことが予想される領域が、導光部材の一方の端部側とは異なる場合であっても適用できる。 In the first embodiment and other embodiments, the toner container is disposed on one end side of the developing unit, and the light source is disposed on the same side as the toner container in the longitudinal direction of the light guide member. The present invention can also be applied to an image forming apparatus in which a toner container and / or a light source is provided at a position different from that in the above embodiment. That is, the present invention can be applied even when the region of the light guide member that is expected to have a high degree of toner contamination is different from the one end side of the light guide member.

１０：画像形成装置
１９：トナーコンテナ
１９３：トナー排出口
２：感光体ドラム
４：現像部
４２：トナー導入口
５，５Ａ〜５Ｇ：除電部
５１：光源
５２，５２Ａ〜５２Ｇ：導光部材
５２３：基部
５２４：レンズ部
５２６：反射部Ｅ
５２７，５２７Ａ〜５２７Ｇ：凹部
５３１：第１領域
５３２：第２領域
５３３：中間領域
９：連結部 10: Image forming apparatus 19: Toner container 193: Toner discharge port 2: Photoreceptor drum 4: Developing unit 42: Toner introduction port 5, 5A to 5G: Neutralizing unit 51: Light source 52, 52A to 52G: Light guide member 523: Base 524: Lens 526: Reflector E
527, 527A to 527G: recessed portion 531: first region 532: second region 533: intermediate region 9: connecting portion

Claims

An image carrier for carrying a toner image;
A light source that emits light used for charge removal of the image carrier, and a light guide member that guides light incident on one end from the light source along the longitudinal direction and emits charge removal light toward the image carrier. A static eliminator,
With
The charge removal unit emits charge removal light having a larger light amount than the second region in the first region in the longitudinal direction of the light guide member,
The image forming apparatus, wherein the first area is an area where the degree of toner contamination is expected to be higher than that of the second area.

The image forming apparatus according to claim 1, wherein the charge removal unit emits the charge removal light having a light amount distribution in which the light amount tends to increase as the first region is approached in the longitudinal direction.

A developing unit for developing an electrostatic latent image formed on the surface of the image carrier into a toner image;
A toner container for storing toner to be supplied to the developing unit;
Further comprising
3. The image forming apparatus according to claim 1, wherein the first region is closer to the connecting portion between a toner discharge port of the toner container and a toner introduction port of the developing unit than the second region.

The light source emits light toward one end of the light guide member closer to the connection portion,
The light guide member has a plurality of recesses that reflect light traveling in the longitudinal direction inside the light guide member in a direction toward the image carrier,
The image forming apparatus according to claim 3, wherein the plurality of recesses are arranged at equal intervals along the longitudinal direction.

The light guide member has a plurality of recesses that reflect light traveling in the light guide member in a direction toward the image carrier,
The image formation according to claim 1, wherein the first region has a unit concave area that is a total inner area of the plurality of concave portions per unit length in the longitudinal direction larger than that of the second region. apparatus.

The image forming apparatus according to claim 5, wherein an interval between the plurality of concave portions is smaller in the first region than in the second region.

The image forming apparatus according to claim 5, wherein a depth of the plurality of concave portions is larger in the first area than in the second area.

The image forming apparatus according to claim 5, wherein a dimension of the plurality of concave portions in a direction intersecting the longitudinal direction is larger in the first area than in the second area.

The light source emits light toward one end of the light guide member closer to the connection portion,
A plurality of recesses for reflecting light traveling in the longitudinal direction inside the light guide member in a direction toward the image carrier;
The image formation according to claim 1, wherein the second region has a unit concave area that is a total inner area of the plurality of concave portions per unit length in the longitudinal direction larger than that of the first region. apparatus.

The first region is a region on the one end side of the light guide member,
The second region is a region on the other end side through an intermediate region between the first region and the first region,
The image forming apparatus according to claim 9, wherein the unit concave areas of the plurality of concave portions are larger in the order of the second region, the intermediate region, and the first region.

The plurality of recesses in the intermediate region increase in the unit recess area from the first region toward the second region in the longitudinal direction,
The image forming apparatus according to claim 10, wherein a change rate of the unit concave area in the longitudinal direction in the intermediate region is larger than a change rate in the longitudinal direction of the unit concave area in the first region and the second region. .

The image forming apparatus according to claim 11, wherein an interval between the plurality of concave portions is smaller in the order of the second region, the intermediate region, and the first region.

The image forming apparatus according to any one of claims 9 to 12, wherein the static elimination unit includes a reflection unit provided at the other end opposite to the longitudinal direction from the one end of the light guide member.

Each of the plurality of recesses is formed in a shape that expands from the bottom toward the opening,
In the one or more recesses in the plurality of recesses of the first region, the opening is formed in a shape that expands with a larger expansion rate than the bottom.
The image forming apparatus according to claim 4.

The said light guide member has a base part in which these recessed parts are formed, and the lens part which condenses the light reflected by these recessed parts, and radiate | emits the static elimination light. The image forming apparatus described in 1.