JP6291958B2

JP6291958B2 - Developing device and image forming apparatus using the same

Info

Publication number: JP6291958B2
Application number: JP2014066329A
Authority: JP
Inventors: 倉本　新一; 新一倉本; 稲葉　繁; 繁稲葉; 由高中島; 良太冨士
Original assignee: Fuji Xerox Co Ltd; Fujifilm Business Innovation Corp
Current assignee: Fujifilm Business Innovation Corp
Priority date: 2014-03-27
Filing date: 2014-03-27
Publication date: 2018-03-14
Anticipated expiration: 2034-03-27
Also published as: JP2015191021A

Description

本発明は、現像装置及びこれを用いた画像形成装置に関する。 The present invention relates to a developing device and an image forming apparatus using the developing device.

従来この種の現像装置としては特許文献１〜３に記載のものが既に知られている。
特許文献１には、現像スリーブ及び永久磁石からなる現像剤担持体と、これに対向する磁性体からなる現像剤規制部材である丸棒と、を備え、永久磁石と丸棒とによって協働して形成される磁場について、現像スリーブと丸棒との最近接部の間隙の中点における長手方向の磁束密度が、丸棒の両端部近傍において極大値を持つように構成する現像装置が開示されている。
特許文献２には、円筒部材及び磁石部材を有する現像剤保持体と、現像剤保持体に対向して設けられ磁性材料製の円筒状の層厚規制部材と、を備え、円筒部材の直径をＤ、層厚規制部材を円筒部材に投影した差異の投影幅をＷとし、角度α＝１８０×Ｗ／（Ｄ×π）とした場合に、層厚規制部材よりも円筒部材回転方向下流側の角度αの領域外に、層厚保規制部材の円筒部材回転方向下流側で層厚規制部材に最も近い位置に配置された磁極の法線方向磁束密度分布の極大位置が配置される現像装置が開示されている。
特許文献３には、現像剤層規制部材が非磁性の金属丸棒から成り、現像剤層規制部材が弾性部材により付勢されて現像スリーブに圧接し、現像スリーブ上の現像剤搬送量を規制する現像装置が開示されている。 Conventionally, as this type of developing device, those described in Patent Documents 1 to 3 are already known.
Patent Document 1 includes a developer carrying member composed of a developing sleeve and a permanent magnet, and a round bar that is a developer regulating member made of a magnetic material facing the developing sleeve, and cooperates with the permanent magnet and the round bar. A developing device is disclosed in which the magnetic flux density in the longitudinal direction at the midpoint of the gap between the closest portions of the developing sleeve and the round bar has a maximum value in the vicinity of both ends of the round bar. ing.
Patent Document 2 includes a developer holding body having a cylindrical member and a magnet member, and a cylindrical layer thickness regulating member made of a magnetic material provided to face the developer holding body, and the diameter of the cylindrical member is D, when the projected width of the difference between the projection of the layer thickness regulating member onto the cylindrical member is W and the angle α = 180 × W / (D × π), the cylindrical member rotating direction downstream side of the layer thickness regulating member Disclosed is a developing device in which the maximum position of the magnetic flux density distribution in the normal direction of the magnetic pole arranged at the position closest to the layer thickness regulating member on the downstream side in the rotation direction of the cylindrical member of the layer thickness keeping regulating member is disposed outside the area of the angle α. Has been.
In Patent Document 3, the developer layer restricting member is made of a nonmagnetic metal round bar, and the developer layer restricting member is urged by an elastic member to come into pressure contact with the developing sleeve, thereby restricting the developer conveyance amount on the developing sleeve. A developing device is disclosed.

特開平８−２１１７４５号公報（実施例，図１）Japanese Patent Laid-Open No. 8-21745 (Example, FIG. 1) 特開２００８−２７５７１９号公報（発明を実施するための最良の形態，図６）JP 2008-275719 A (Best Mode for Carrying Out the Invention, FIG. 6) 特開平１１−２６５１１７号公報（発明の実施の形態，図３）Japanese Patent Laid-Open No. 11-265117 (Embodiment of the Invention, FIG. 3)

本発明が解決しようとする技術的課題は、層規制部材へのトナーの経時付着を抑制し、現像剤の層厚を正確に規制することにある。 The technical problem to be solved by the present invention is to suppress the adhesion of toner to the layer regulating member with time and regulate the developer layer thickness accurately.

請求項１に係る発明は、中空状の現像回転体、及び、前記現像回転体内に固定的に設けられ且つ周囲に複数の磁極が配列される磁石部材を有し、前記現像回転体を回転させることで前記磁石部材による磁力にて前記現像回転体上にトナー及び磁性キャリアが含まれる現像剤を保持する現像剤保持体と、この現像剤保持体より下方に設けられ、前記現像剤保持体に対して前記現像剤を供給する現像剤供給部材と、前記現像剤保持体と非接触となるように間隙を介して対向配置され、少なくとも現像剤保持体に向かって突出する断面円弧状の曲面部を有し、前記現像剤保持体上に保持される現像剤の層厚を規制する層規制部材と、この層規制部材と前記現像剤供給部材との間に設けられ、前記現像剤供給部材から供給される現像剤のうち層規制部材に向かう経路をせき止めるせき止め部材と、を備え、前記せき止め部材は、前記現像剤供給部材の外周部のうち層規制部材側端を通る鉛直線位置から前記現像剤供給部材側に突出し、前記現像剤供給部材の中心を通る鉛直線位置には至らない範囲で前記現像剤供給部材の外周部を覆い、せき止めた現像剤を前記現像剤保持体側に案内する案内部を有し、前記案内部の前記現像剤保持体側には前記層規制部材から前記現像剤保持体による現像剤の搬送方向上流側に突出して前記現像剤保持体に対向する対向面を形成することを特徴とする現像装置である。 The invention according to claim 1 includes a hollow developing rotator, and a magnet member fixedly provided in the developing rotator and having a plurality of magnetic poles arranged around it, and rotates the developing rotator. Thus, a developer holder that holds the developer containing toner and magnetic carrier on the developing rotator by the magnetic force of the magnet member, and a developer holder that is provided below the developer holder, the developer holder On the other hand, a developer supply member that supplies the developer and a curved surface portion having an arcuate cross section that is disposed so as to be in contact with the developer holding body through a gap so as to be in non-contact with the developer holding body. A layer regulating member that regulates the layer thickness of the developer held on the developer holder, and is provided between the layer regulating member and the developer supply member, and from the developer supply member Of the supplied developer, the layer control section A damming member that dams a path toward the developer, the damming member projecting toward the developer supply member from a vertical line position passing through a layer regulating member side end of the outer periphery of the developer supply member, and a range that does not lead to a vertical line position passing through the center of the supply member covers the outer peripheral portion of the developer supplying member, a cough developer has a guide portion for guiding the developer holder side, the said guide portion The developing device is characterized in that an opposing surface is formed on the developer holding member side so as to protrude from the layer regulating member to the upstream side of the developer conveying direction by the developer holding member and to face the developer holding member .

請求項２に係る発明は、請求項１に係る現像装置において、前記対向面には、前記層規制部材側に向かって水平面よりも斜め上方に傾斜する傾斜面を有することを特徴とする現像装置である。
請求項３に係る発明は、請求項１又は２に係る現像装置において、前記案内部は、前記現像剤保持体の中心を通る鉛直線位置を越えない範囲で形成されていることを特徴とする現像装置である。
請求項４に係る発明は、請求項１乃至３のいずれかに係る現像装置において、前記現像剤保持体は、前記層規制部材に対応する部位に層規制磁極を備え、当該層規制磁極により前記層規制部材に作用する磁力が５０ｍＴ以上であることを特徴とする現像装置である。
請求項５に係る発明は、請求項１乃至４のいずれかに係る現像装置において、前記層規制部材の曲面部はＲａが０．２以上の表面粗さを有していることを特徴とする現像装置である。
請求項６に係る発明は、静電潜像が保持される像保持体と、この像保持体上の静電潜像を対応する現像剤にて現像する請求項１乃至５のいずれかに係る現像装置と、を備えたことを特徴とする画像形成装置である。 According to a second aspect of the present invention, in the developing device according to the first aspect, the opposing surface has an inclined surface that is inclined obliquely upward from the horizontal plane toward the layer regulating member side. It is.
According to a third aspect of the present invention, in the developing device according to the first or second aspect , the guide portion is formed within a range not exceeding a vertical line position passing through a center of the developer holding body. It is a developing device.
According to a fourth aspect of the present invention, in the developing device according to any one of the first to third aspects, the developer holder includes a layer regulating magnetic pole at a portion corresponding to the layer regulating member, and the layer regulating magnetic pole is used to The developing device is characterized in that the magnetic force acting on the layer regulating member is 50 mT or more.
According to a fifth aspect of the present invention, in the developing device according to any one of the first to fourth aspects, the curved surface portion of the layer regulating member has a surface roughness Ra of 0.2 or more. It is a developing device.
Invention relates the image carrier on which an electrostatic latent image is maintained, in any one of claims 1 to 5 for developing an electrostatic latent image on the image carrier by the corresponding developer according to claim 6 An image forming apparatus comprising: a developing device.

請求項１に係る発明によれば、層規制部材へのトナーの経時付着を抑制することができる。
請求項２に係る発明によれば、本構成を有さない態様に比べて、層規制部材へ向かう傾斜面に沿って現像剤を案内することができる。
請求項３に係る発明によれば、本構成を有さない態様に比べて、現像剤保持体に現像剤を安定的に供給することができる。
請求項４に係る発明によれば、本構成を有さない態様に比べて、層規制部材へのトナーの経時付着をより抑制することができる。
請求項５に係る発明によれば、本構成を有さない態様に比べて、層規制部材にて層規制される現像剤の搬送量の経時安定性を向上することができる。
請求項６に係る発明によれば、層規制部材へのトナーの経時付着を抑制することが可能な現像装置を含む画像形成装置を提供することができる。 According to the first aspect of the present invention, it is possible to suppress the adhesion of toner to the layer regulating member over time.
According to the invention which concerns on Claim 2, compared with the aspect which does not have this structure, a developer can be guided along the inclined surface which goes to a layer control member.
According to the invention which concerns on Claim 3 , compared with the aspect which does not have this structure, a developer can be stably supplied to a developer holding body.
According to the fourth aspect of the present invention, it is possible to further prevent the toner from adhering to the layer regulating member over time as compared with the aspect not having this configuration.
According to the invention which concerns on Claim 5 , compared with the aspect which does not have this structure, the temporal stability of the conveyance amount of the developer by which a layer control member controls a layer can be improved.
According to the sixth aspect of the present invention, it is possible to provide an image forming apparatus including a developing device capable of suppressing the adhesion of toner to the layer regulating member over time.

本発明が適用された現像装置を含む画像形成装置の実施の形態の概要を示す説明図である。1 is an explanatory diagram showing an outline of an embodiment of an image forming apparatus including a developing device to which the present invention is applied. 実施の形態１に係る画像形成装置の全体構成を示す説明図である。1 is an explanatory diagram illustrating an overall configuration of an image forming apparatus according to a first embodiment. 実施の形態１で用いられるプロセスカートリッジの構成を示す説明図である。FIG. 3 is an explanatory diagram showing a configuration of a process cartridge used in the first embodiment. 実施の形態１で用いられる現像装置の要部を示す説明図である。FIG. 2 is an explanatory diagram showing a main part of a developing device used in Embodiment 1. 実施の形態１で用いられる現像装置の現像剤の搬送挙動を示す説明図である。FIG. 4 is an explanatory diagram illustrating a developer transport behavior of the developing device used in the first embodiment. （ａ）は層規制ロールと現像ロールとの間の磁力線パターン例を示す説明図、（ｂ）は層規制ロールと現像剤による磁気ブラシとの関係を示す説明図である。(A) is explanatory drawing which shows the example of a magnetic force line pattern between a layer control roll and a developing roll, (b) is explanatory drawing which shows the relationship between the layer control roll and the magnetic brush by a developing agent. 比較の形態１で用いられる現像装置の要部及びその現像剤の搬送挙動を示す説明図である。It is explanatory drawing which shows the principal part of the image development apparatus used by the form 1 of a comparison, and the conveyance behavior of the developer. 実施例１，２及び比較例１〜３における現像剤搬送量差（ΔＭＯＳ）を調べた説明図である。It is explanatory drawing which investigated the developer conveyance amount difference ((DELTA) MOS) in Example 1, 2 and Comparative Examples 1-3. 層規制磁極（Ｔ極）の磁力及びせき止めブロックによるトナー痕への影響を示すグラフ図、（ｂ）は（ａ）中のＩの条件でのトナー痕の発生状態を模式的に示す説明図、（ｃ）は（ａ）中のＩＩの条件でのトナー痕の発生状態を模式的に示す説明図である。FIG. 7 is a graph showing the influence of the magnetic force of the layer-regulating magnetic pole (T pole) on the toner mark due to the blocking block, and (b) is an explanatory view schematically showing the state of occurrence of the toner mark under the condition I in (a). (C) is an explanatory view schematically showing the state of occurrence of toner marks under the condition II in (a). （ａ）は実施例３における作像枚数の増加に伴う数現像剤搬送量の変化を示す説明図、（ｂ）は比較例３における作像枚数の増加に伴う数現像剤搬送量の変化を示す説明図である。(A) is explanatory drawing which shows the change of the number developer conveyance amount accompanying the increase in the number of image formation in Example 3, (b) is the change of the number developer conveyance amount accompanying the increase in the number of image formation in Comparative Example 3. It is explanatory drawing shown.

◎実施の形態の概要
図１は本発明が適用された現像装置を含む画像形成装置の実施の形態の概要を示す。
同図において、画像形成装置は、静電潜像が保持される像保持体１１と、この像保持体１１上の静電潜像を対応する現像剤にて現像する現像装置１２と、を備えている。
そして、本例においては、現像装置１２は、中空状の現像回転体２、及び、前記現像回転体２内に固定的に設けられ且つ周囲に複数の磁極４（例えば４ａ〜４ｅ）が配列される磁石部材３を有し、現像回転体２を回転させることで磁石部材３による磁力にて現像回転体２上にトナー及び磁性キャリアが含まれる現像剤を保持する現像剤保持体１と、この現像剤保持体１より下方に設けられ、現像剤保持体１に対して現像剤を供給する現像剤供給部材５と、現像剤保持体１と非接触となるように間隙を介して対向配置され、少なくとも現像剤保持体１に向かって突出する断面円弧状の曲面部７ａを有し、現像剤保持体１上に保持される現像剤の層厚を規制する層規制部材７と、この層規制部材７と現像剤供給部材５との間に設けられ、現像剤供給部材５から供給される現像剤のうち層規制部材７に向かう経路をせき止めるせき止め部材８と、を備え、せき止め部材８は、現像剤供給部材５の外周部のうち層規制部材７側端を通る鉛直線位置Ｌ１から現像剤供給部材５側に突出し、現像剤供給部材５の中心を通る鉛直線位置Ｌ２には至らない範囲で前記現像剤供給部材５の外周部を覆い、せき止めた現像剤を現像剤保持体１側に案内する案内部９を有し、案内部９の現像剤保持体１側には層規制部材７から現像剤保持体１による現像剤の搬送方向上流側に突出して現像剤保持体１に対向する対向面を形成したものである。
尚、符号１３は現像剤保持体１、現像剤供給部材５、撹拌搬送部材６、層規制部材７、せき止め部材８が収容される現像容器である。 Outline of Embodiment FIG. 1 shows an outline of an embodiment of an image forming apparatus including a developing device to which the present invention is applied.
In FIG. 1, the image forming apparatus includes an image carrier 11 that holds an electrostatic latent image, and a developing device 12 that develops the electrostatic latent image on the image carrier 11 with a corresponding developer. ing.
In this example, the developing device 12 is provided with a hollow developing rotator 2, and a plurality of magnetic poles 4 (for example, 4a to 4e) arranged around the developing rotator 2 in a fixed manner. A developer holding body 1 that holds a developer containing toner and a magnetic carrier on the developing rotator 2 by rotating the developing rotator 2 by the magnetic force of the magnet member 3, A developer supply member 5 that is provided below the developer holder 1 and that supplies the developer to the developer holder 1 is opposed to the developer holder 1 via a gap so as to be in non-contact with the developer holder 1. A layer regulating member 7 which has at least a curved surface portion 7a having an arcuate cross section projecting toward the developer holding body 1 and regulates the layer thickness of the developer held on the developer holding body 1; Provided between the member 7 and the developer supply member 5, A clogging member 8 that clogs a path toward the layer regulating member 7 among the developer supplied from the member 5, and the clogging member 8 passes through the end of the developer supplying member 5 on the side of the layer regulating member 7. The developer that covers the outer periphery of the developer supply member 5 and prevents the developer from projecting to the developer supply member 5 side from the vertical line position L1 and not reaching the vertical line position L2 passing through the center of the developer supply member 5 is provided. The guide 9 has a guide portion 9 that guides to the developer holding body 1 side, and the developer holding body 1 side of the guide portion 9 projects from the layer regulating member 7 to the upstream side in the developer transport direction by the developer holding body 1. A facing surface facing the agent holding body 1 is formed .
Reference numeral 13 denotes a developing container in which the developer holding body 1, the developer supplying member 5, the stirring and conveying member 6, the layer regulating member 7, and the damming member 8 are accommodated.

このような技術的手段において、像保持体１１は静電潜像を保持するものであれば感光体、誘電体など適宜選定して差し支えない。また、現像装置１２としては、像保持体１１上の静電潜像を現像剤にて現像するものであれば適宜選定して差し支えない。
ここで、現像剤保持体１は、現像回転体２と磁石部材３とを有し、所謂磁気ブラシ現像を実施するものであればよい。
また、現像剤供給部材５は、現像剤保持体１よりも下方に位置していればよく、現像剤を撹拌搬送する撹拌搬送部材６を兼用してもよいし、現像剤の撹拌搬送部材６とは別に設けても差し支えない。
更に、層規制部材７は断面円形のロール状部材が代表的であるが、これに限らず、少なくとも現像剤保持体１に対向する部分が断面円弧状の曲面部７ａを有するものであればよい。また、層規制部材７は磁性、非磁性を問わないが、磁性を有する方が層規制部材７に作用する磁力を大きく出来る点で好ましい。
更にまた、せき止め部材８は、層規制部材７と現像剤供給部材５との間に設けられ、現像剤供給部材５からの現像剤が直接層規制部材７に向かうのをせき止めるものであればよい。但し、せき止めた現像剤を現像剤保持体１側に導くために所定の案内部９を有することが必要である。
せき止め部材８がないと、現像剤供給部材５から供給される現像剤の一部が直接層規制部材７に到達し、層規制部材７にトナーが経時付着する。このため、層規制部材７を通過する現像剤の搬送量が変化してしまい、その分、現像剤の層厚が変化してしまう懸念があるが、本例では、せき止め部材８の存在でこのようなトナーの経時付着が抑制される。 In such technical means, the image carrier 11 may be appropriately selected from a photoconductor and a dielectric as long as it holds an electrostatic latent image. The developing device 12 may be appropriately selected as long as the electrostatic latent image on the image carrier 11 is developed with a developer.
Here, the developer holding body 1 has only to have a developing rotator 2 and a magnet member 3 and performs so-called magnetic brush development.
Further, the developer supply member 5 only needs to be positioned below the developer holder 1, and may also serve as the agitation transport member 6 that stirs and transports the developer, or the developer agitation transport member 6. It can be provided separately.
Furthermore, the layer regulating member 7 is typically a roll-shaped member having a circular cross section, but is not limited thereto, and any member may be used as long as at least a portion facing the developer holding body 1 has a curved surface portion 7a having an arc-shaped cross section. . The layer regulating member 7 may be either magnetic or non-magnetic, but it is preferable that the layer regulating member 7 has magnetism from the viewpoint that the magnetic force acting on the layer regulating member 7 can be increased.
Furthermore, the damming member 8 may be any member as long as it is provided between the layer regulating member 7 and the developer supply member 5 and blocks the developer from the developer feeding member 5 directly toward the layer regulating member 7. . However, it is necessary to have a predetermined guide portion 9 in order to guide the blocked developer to the developer holding body 1 side.
Without the damming member 8, a part of the developer supplied from the developer supply member 5 reaches the layer regulating member 7 directly, and the toner adheres to the layer regulating member 7 with time. For this reason, there is a concern that the developer transport amount passing through the layer regulating member 7 changes, and the layer thickness of the developer changes accordingly, but in this example, the presence of the damming member 8 Such adhesion of toner over time is suppressed.

次に、本実施の形態に係る現像装置の好ましい態様について説明する。
先ず、案内部９の好ましい態様としては、現像剤保持体１の中心を通る鉛直線位置Ｌ３を越えない範囲で形成されている態様が挙げられる。本態様では、現像剤供給部材５から供給された現像剤はせき止め部材８の案内部９に沿って現像剤保持体１に向かうが、案内部９の先端が現像剤保持体１の最下端付近に位置するため、現像剤は現像剤保持体１の最下端付近に集中して供給される点で好ましい。
また、層規制部材７に作用する磁力の好ましい態様としては、現像剤保持体１は、層規制部材７に対応する部位に層規制磁極（本例では４ｂ）を備え、当該層規制磁極４ｂにより層規制部材７に作用する磁力が５０ｍＴ以上である態様が挙げられる。本態様では、層規制部材７を通過する領域で５０ｍＴ以上の磁力があれば、その磁気ブラシの腰が強くなり、層規制部材７の表面を強く摺擦することから、層規制部材７の表面にトナーが付着しようとしても、当該トナーは磁気ブラシにより掻き取られると推測される。
更に、層規制部材７の好ましい態様としては、層規制部材７の曲面部７ａはＲａが０．２以上の表面粗さを有している態様が挙げられる。ここで、層規制部材７の表面特性として、Ｒａを０．２未満にすると、層規制部材７の表面が平滑過ぎて現像剤が層規制部材７によって層規制される規制部位で現像剤保持体１の回転方向に沿って移動しやすいのに対し、０．２以上にすると、規制部位で現像剤保持体１の回転方向に沿って移動することを抑制し、現像剤の搬送量を略均一に規制することができるものと推測される。 Next, a preferable aspect of the developing device according to the present embodiment will be described.
First, as a preferable aspect of the guide portion 9, an aspect in which the guide portion 9 is formed in a range not exceeding the vertical line position L <b> 3 passing through the center of the developer holding body 1 can be given. In this embodiment, the developer supplied from the developer supply member 5 is directed to the developer holding body 1 along the guide portion 9 of the dampening member 8, but the tip of the guide portion 9 is near the lowermost end of the developer holding body 1. Therefore, the developer is preferable in that it is concentrated and supplied in the vicinity of the lowermost end of the developer holder 1.
Further, as a preferable aspect of the magnetic force acting on the layer regulating member 7, the developer holder 1 includes a layer regulating magnetic pole (4b in this example) at a portion corresponding to the layer regulating member 7, and the layer regulating magnetic pole 4b The aspect which the magnetic force which acts on the layer control member 7 is 50 mT or more is mentioned. In this aspect, if there is a magnetic force of 50 mT or more in the region passing through the layer regulating member 7, the magnetic brush becomes strong and rubs the surface of the layer regulating member 7 strongly. Even if the toner tries to adhere to the toner, it is assumed that the toner is scraped off by the magnetic brush.
Furthermore, as a preferable aspect of the layer restricting member 7, an aspect in which the curved surface portion 7a of the layer restricting member 7 has a surface roughness Ra of 0.2 or more can be mentioned. Here, if Ra is less than 0.2 as the surface characteristic of the layer regulating member 7, the surface of the layer regulating member 7 is too smooth, and the developer holding body is in a regulated region where the developer is layer regulated by the layer regulating member 7. 1 is easy to move along the rotation direction of 1. However, if it is 0.2 or more, the movement of the developer holding body 1 along the rotation direction of the regulating portion is suppressed, and the developer transport amount is substantially uniform. It is estimated that it can be regulated.

以下、添付図面に示す実施の形態に基づいて本発明をより詳細に説明する。
◎実施の形態１
＜画像形成装置の全体構成＞
図２は本発明が適用された画像形成装置の実施の形態１を示す説明図である。
同図において、画像形成装置２０は、装置筐体２１内に四つの色（本実施の形態ではブラック、イエロ、マゼンタ、シアン）の画像形成部２２（具体的には２２ａ〜２２ｄ）を横方向に配列し、その上方には各画像形成部２２の配列方向に沿って循環搬送される中間転写ベルト２３０が含まれる転写モジュール２３を配設する一方、装置筐体２１の下方には用紙等の記録材が収容される記録材供給装置２４を配設すると共に、この記録材供給装置２４からの記録材搬送路２５を略鉛直方向に配置したものである。 Hereinafter, the present invention will be described in more detail based on embodiments shown in the accompanying drawings.
Embodiment 1
<Overall configuration of image forming apparatus>
FIG. 2 is an explanatory view showing Embodiment 1 of the image forming apparatus to which the present invention is applied.
In the figure, an image forming apparatus 20 arranges image forming units 22 (specifically, 22a to 22d) of four colors (black, yellow, magenta, and cyan in this embodiment) in an apparatus casing 21 in the horizontal direction. A transfer module 23 including an intermediate transfer belt 230 that is circulated and conveyed along the arrangement direction of the image forming units 22 is disposed above the image forming unit 22. A recording material supply device 24 that accommodates the recording material is disposed, and a recording material conveyance path 25 from the recording material supply device 24 is disposed in a substantially vertical direction.

本実施の形態において、各画像形成部２２（２２ａ〜２２ｄ）は、中間転写ベルト２３０の循環方向上流側から順に、例えばブラック用、イエロ用、マゼンタ用、シアン用（配列は必ずしもこの順番とは限らない）のトナー像を形成するものであり、感光体３１と、この感光体３１を予め帯電する帯電装置（本例では帯電ロール）３２と、この帯電装置３２にて帯電された各感光体３１に静電潜像を書き込む露光装置３３（本例では各画像形成部２２に共通の露光装置を使用）と、感光体３１上に形成された静電潜像を対応する色トナー（本実施の形態では例えば負極性）で現像する現像装置３４と、感光体３１上の残留物を清掃する清掃装置３５と、を備えている。
ここで、露光装置３３は、露光筐体４１内に例えば四つの半導体レーザ（図示せず）、一つのポリゴンミラー４２、結像レンズ（図示せず）及び各感光体に対応するそれぞれミラー（図示せず）を格納し、各色成分の半導体レーザからの光をポリゴンミラー４２で偏向走査し、結像レンズ、ミラーを介して対応する感光体３１上の露光ポイントに光像を導くようにしたものである。
尚、符号３６（３６ａ〜３６ｄ）は各現像装置３４に各色成分トナーを補給するためのトナーカートリッジである。
また、本実施の形態において、転写モジュール２３は、例えば一対の張架ロール（一方が駆動ロール）２３１，２３２間に中間転写ベルト２３０を掛け渡したものであり、各画像形成部２２の感光体３１に対応した中間転写ベルト２３０の裏面には一次転写装置（本例では一次転写ロール）５１が配設され、この一次転写装置５１にトナーの帯電極性と逆極性の電圧を印加することで、感光体３１上のトナー像を中間転写ベルト２３０側に静電的に転写するようになっている。
更に、中間転写ベルト２３０の最下流画像形成部２２ｄの下流側の張架ロール２３２に対応した部位には二次転写装置５２が配設されており、中間転写ベルト２３０上の一次転写像を記録材に二次転写（一括転写）するようになっている。 In the present embodiment, the image forming units 22 (22a to 22d) are, for example, for black, yellow, magenta, and cyan in order from the upstream side in the circulation direction of the intermediate transfer belt 230. (Not limited to) a toner image, a photoreceptor 31, a charging device (charging roll in this example) 32 that charges the photoreceptor 31 in advance, and each photoreceptor charged by the charging device 32. An exposure device 33 that writes an electrostatic latent image on 31 (in this example, a common exposure device is used for each image forming unit 22), and a corresponding color toner (this embodiment) that forms an electrostatic latent image formed on the photoreceptor 31. In this embodiment, a developing device 34 that develops with negative polarity, for example, and a cleaning device 35 that cleans the residue on the photoreceptor 31 are provided.
Here, the exposure apparatus 33 includes, for example, four semiconductor lasers (not shown), one polygon mirror 42, an imaging lens (not shown), and mirrors corresponding to the respective photoreceptors (see FIG. (Not shown), the light from the semiconductor laser of each color component is deflected and scanned by the polygon mirror 42, and the light image is guided to the exposure point on the corresponding photoreceptor 31 through the imaging lens and mirror. It is.
Reference numeral 36 (36a to 36d) denotes a toner cartridge for replenishing each developing device 34 with each color component toner.
Further, in the present embodiment, the transfer module 23 is, for example, a structure in which an intermediate transfer belt 230 is stretched between a pair of stretch rolls (one is a drive roll) 231 and 232, and the photoreceptor of each image forming unit 22. A primary transfer device (primary transfer roll 51 in this example) 51 is disposed on the back surface of the intermediate transfer belt 230 corresponding to 31, and a voltage having a polarity opposite to the charging polarity of the toner is applied to the primary transfer device 51, The toner image on the photoreceptor 31 is electrostatically transferred to the intermediate transfer belt 230 side.
Further, a secondary transfer device 52 is disposed at a portion corresponding to the tension roll 232 on the downstream side of the most downstream image forming unit 22d of the intermediate transfer belt 230, and a primary transfer image on the intermediate transfer belt 230 is recorded. Secondary transfer (collective transfer) is performed on the material.

本実施の形態では、二次転写装置５２は、中間転写ベルト２３０のトナー像保持面側に圧接配置される二次転写ロール５２１と、中間転写ベルト２３０の裏面側に配置されて二次転写ロール５２１の対向電極をなすバックアップロール（本例では張架ロール２３２を兼用）とを備えている。
そして、例えば二次転写ロール５２１が接地されており、また、バックアップロール（張架ロール２３２）にはトナーの帯電極性と同極性のバイアスが印加されている。
更にまた、中間転写ベルト２３０の最上流画像形成部２２ａの上流側にはベルト清掃装置５３が配設されており、中間転写ベルト２３０上の残留トナーを除去するようになっている。 In the present embodiment, the secondary transfer device 52 includes a secondary transfer roll 521 arranged in pressure contact with the toner image holding surface side of the intermediate transfer belt 230, and a secondary transfer roll disposed on the back side of the intermediate transfer belt 230. A backup roll (in this example, also serving as a stretching roll 232) is provided.
For example, the secondary transfer roll 521 is grounded, and a bias having the same polarity as the charging polarity of the toner is applied to the backup roll (stretching roll 232).
Furthermore, a belt cleaning device 53 is disposed on the upstream side of the most upstream image forming portion 22a of the intermediate transfer belt 230 so as to remove residual toner on the intermediate transfer belt 230.

また、記録材供給装置２４には記録材を供給する供給ロール６１が設けられ、この供給ロール６１の直後には記録材を搬送する搬送ロール６２が配設されると共に、二次転写部位の直前に位置する記録材搬送路２５には記録材を所定のタイミングで二次転写部位へ供給する位置決めロール（レジストレーションロール）６３が配設されている。
一方、二次転写部位の下流側に位置する記録材搬送路２５には定着装置６６が設けられ、この定着装置６６は、図２に示すように、図示外の加熱ヒータが内蔵された加熱定着ロール６６ａと、これに圧接配置されて追従回転する加圧定着ロール６６ｂとを備えている。
また、定着装置６６の下流側には記録材排出装置６７が設けられている。この記録材排出装置６７は装置筐体２１内の記録材を排出する対構成の排出ロール６７ａ，６７ｂからなり、記録材を挟持搬送して排出し、装置筐体２１の上部に形成された記録材収容受け６８に記録材を収容するようになっている。
更に、本実施の形態では、装置筐体２１の側方には手差し供給装置（ＭＳＩ）７１が設けられており、この手差し供給装置７１上の記録材は供給ロール７２にて記録材搬送路２５に向かって供給されるようになっている。
更にまた、装置筐体２１には両面記録モジュール７３が付設されており、この両面記録モジュール７３は、記録材の両面に画像記録を行う両面モード選択時に、記録材排出装置６７を逆転させ、かつ、入口手前の案内ロール７４にて片面記録済みの記録材を内部に取り込み、適宜数の搬送ロール７７にて内部の記録材戻し搬送路７６に沿って記録材を搬送し、再度位置決めロール６３側へと供給するものである。 Further, the recording material supply device 24 is provided with a supply roll 61 for supplying a recording material. A transport roll 62 for transporting the recording material is disposed immediately after the supply roll 61 and immediately before the secondary transfer site. A positioning roll (registration roll) 63 for supplying the recording material to the secondary transfer portion at a predetermined timing is disposed in the recording material conveyance path 25 positioned at the position.
On the other hand, a fixing device 66 is provided in the recording material conveyance path 25 located on the downstream side of the secondary transfer site. As shown in FIG. 2, the fixing device 66 is a heat fixing in which a heater (not shown) is incorporated. A roll 66a and a pressure fixing roll 66b that is arranged in pressure contact with the roll 66 and rotates following the roll 66a are provided.
A recording material discharge device 67 is provided on the downstream side of the fixing device 66. The recording material discharge device 67 includes paired discharge rollers 67 a and 67 b for discharging the recording material in the apparatus housing 21. The recording material is sandwiched and conveyed to be discharged, and is formed on the upper portion of the apparatus housing 21. A recording material is accommodated in the material accommodating receptacle 68.
Further, in the present embodiment, a manual feed device (MSI) 71 is provided on the side of the apparatus housing 21, and the recording material on the manual feed device 71 is supplied by the supply roll 72 to the recording material conveyance path 25. It is to be supplied towards.
Furthermore, a double-sided recording module 73 is attached to the apparatus housing 21. The double-sided recording module 73 reverses the recording material discharging device 67 when selecting the double-sided mode in which image recording is performed on both sides of the recording material, and Then, the recording material on which one-side recording has been performed is taken into the inside by the guide roll 74 before the entrance, the recording material is conveyed along the internal recording material return conveyance path 76 by an appropriate number of conveyance rolls 77, and the positioning roll 63 side again. To supply.

−プロセスカートリッジ−
本実施の形態では、各画像形成部２２は、図３に示すように、感光体３１、帯電装置３２、現像装置３４及び清掃装置３５を一体化したプロセスカートリッジ１００として構成され、装置筐体２１の組立体受部Ｕに対して着脱可能に装着されるようになっている。
特に、本例では、プロセスカートリッジ１００は、感光体３１が組み込まれる感光体組立体１０１と、この感光体組立体１０１に対向するように設けられ、現像装置３４が組み込まれる現像組立体１０２と、を有し、感光体組立体１０１及び現像組立体１０２が装置筐体２１の対応する組立体受部Ｕに着脱されるが、本例では、感光体組立体１０１及び現像組立体１０２の寿命の違いを考慮し、感光体組立体１０１及び現像組立体１０２が組立体受部Ｕに対し個々に挿抜可能に装着されるようになっている。例えばプロセスカートリッジ１００の感光体組立体１０１のみを交換する場合には、装置筐体２１の組立体受部Ｕに現像組立体１０２を残したまま、感光体組立体１０１を引き抜いた後、新しい感光体組立体１０１を挿入するようにすればよい。 -Process cartridge-
In the present embodiment, each image forming unit 22 is configured as a process cartridge 100 in which a photosensitive member 31, a charging device 32, a developing device 34, and a cleaning device 35 are integrated as shown in FIG. The assembly receiving portion U is detachably mounted.
In particular, in this example, the process cartridge 100 includes a photoconductor assembly 101 in which the photoconductor 31 is incorporated, a developing assembly 102 that is provided to face the photoconductor assembly 101 and in which the developing device 34 is incorporated, The photosensitive member assembly 101 and the developing assembly 102 are attached to and detached from the corresponding assembly receiving portion U of the apparatus housing 21, but in this example, the lifetime of the photosensitive member assembly 101 and the developing assembly 102 is reduced. In consideration of the difference, the photosensitive member assembly 101 and the developing assembly 102 are attached to the assembly receiving portion U so as to be individually insertable and removable. For example, when only the photoconductor assembly 101 of the process cartridge 100 is replaced, after the photoconductor assembly 101 is pulled out with the developing assembly 102 remaining in the assembly receiving portion U of the apparatus housing 21, a new photosensitivity is obtained. The body assembly 101 may be inserted.

＜感光体組立体＞
本例では、感光体組立体１０１は、図３に示すように、感光体３１が収容される収容容器１１０を有し、この収容容器１１０内の感光体３１の周囲には帯電装置３２及び清掃装置３５を配設したものである。
ここで、感光体３１はその回転軸両端部が収容容器１１０の両端に回転自在に支持されており、感光体組立体１０１装着時には感光体３１の回転軸の一端が図示外の駆動機構に駆動連結されるようになっている。
また、帯電装置３２は、収容容器１１０の一部に帯電容器部１１１を設け、この帯電容器部１１１内に感光体３１の表面に接触若しくは近接する帯電ロール１１２及びこの帯電ロール１１２に給電する給電ロール１１３を設けたものである。
更に、清掃装置３５は、収容容器１１０の一部に清掃容器部１１４を設け、この清掃容器部１１４の開口縁には感光体３１表面の残留トナーが掻き取られる板状の清掃部材１１５を設けると共に、この清掃容器部１１４内には清掃部材１１５で掻き取られた残留トナーが図示外の回収容器に向けて搬送される回収搬送部材（例えば回転軸の周囲に螺旋状羽根を付した態様）１１６を配設したものである。 <Photoreceptor assembly>
In this example, as shown in FIG. 3, the photoreceptor assembly 101 includes a housing container 110 in which the photoreceptor 31 is housed, and a charging device 32 and a cleaning device are disposed around the photoreceptor 31 in the housing container 110. A device 35 is provided.
Here, both ends of the rotating shaft of the photosensitive member 31 are rotatably supported by both ends of the container 110. When the photosensitive member assembly 101 is mounted, one end of the rotating shaft of the photosensitive member 31 is driven by a driving mechanism (not shown). It is designed to be connected.
In addition, the charging device 32 includes a charging container portion 111 provided in a part of the housing container 110, a charging roll 112 that is in contact with or close to the surface of the photoreceptor 31 in the charging container portion 111, and power feeding that supplies power to the charging roll 112. A roll 113 is provided.
Further, the cleaning device 35 is provided with a cleaning container portion 114 in a part of the storage container 110, and a plate-shaped cleaning member 115 that scrapes residual toner on the surface of the photoreceptor 31 is provided at the opening edge of the cleaning container portion 114. At the same time, a recovery conveyance member (for example, a spiral blade around the rotation shaft) in which the residual toner scraped off by the cleaning member 115 is conveyed toward the recovery container (not shown) in the cleaning container portion 114. 116 is disposed.

＜現像組立体＞
現像組立体１０２は、図３に示すように、感光体３１に向かって開口し且つトナー及びキャリアが含まれる二成分現像剤が収容される現像容器１２０を有し、この現像容器１２０の開口に面した部位には現像剤が保持搬送される現像ロール１２１を配設すると共に、現像容器１２０内の現像ロール１２１の背面側には現像剤が撹拌搬送される一対の撹拌搬送部材１２２，１２３を配設し、更に、現像ロール１２１の現像部位よりも回転方向上流側には現像ロール１２１に保持される現像剤の層厚が規制される層規制部材（本例では層規制ロール）１２４を設けたものである。
更に、本例では、現像ロール１２１の両端には現像ロール１２１径よりも僅かに大きい位置調整用のトラッキングロール（図示せず）が設けられ、このトラッキングロールを感光体３１表面に接触させることで現像ロール１２１と感光体３１との間のギャップが予め決められた所定量に調整されるようになっている。そして、現像組立体１０２は、その長手方向の両端付近において夫々付勢バネ（図示せず）によって感光体組立体１０１側に付勢され、トラッキングロールが感光体３１に接触した状態で感光体組立体１０１との位置関係を保つようになっている。 <Development assembly>
As shown in FIG. 3, the developing assembly 102 has a developing container 120 that opens toward the photosensitive member 31 and contains a two-component developer containing toner and a carrier. A developing roll 121 that holds and conveys the developer is disposed on the facing portion, and a pair of agitating and conveying members 122 and 123 that agitate and convey the developer are provided on the back side of the developing roll 121 in the developing container 120. Furthermore, a layer regulating member (in this example, a layer regulating roll) 124 that regulates the layer thickness of the developer held by the developing roll 121 is provided upstream of the developing portion of the developing roll 121 in the rotation direction. It is a thing.
Furthermore, in this example, a position adjusting tracking roll (not shown) slightly larger than the diameter of the developing roll 121 is provided at both ends of the developing roll 121, and the tracking roll is brought into contact with the surface of the photoreceptor 31. The gap between the developing roll 121 and the photoconductor 31 is adjusted to a predetermined amount. The developing assembly 102 is urged toward the photoconductor assembly 101 by an urging spring (not shown) in the vicinity of both ends in the longitudinal direction, and the photoconductor assembly is in a state where the tracking roll is in contact with the photoconductor 31. The positional relationship with the solid 101 is maintained.

−現像装置の代表的要素−
＜現像ロール＞
現像ロール１２１は、図４に示すように、例えばアルミニウム製の円筒状の現像スリーブ１３１と、この現像スリーブ１３１内に固定的に設けられ、周囲に複数（本例では５つ）の磁極が配列される磁石ロール１３２とを備えている。本例では、磁石ロール１３２の磁極としては、現像スリーブ１３１の周囲に現像剤を吸着する吸着磁極（Ｐ極）と、層規制ロール１２４に対応した部位に設けられて層規制ロール１２４との間に現像剤の層厚を規制するための磁力が形成可能な層規制磁極（Ｔ極）と、感光体３１と対向する現像位置に設けられて感光体３１上の静電潜像を現像する現像磁極（Ｄ極）と、現像位置に対して現像スリーブ１３１の回転方向の下流側に設けられる搬送磁極（Ｕ極）と、この搬送磁極（Ｕ極）と吸着磁極（Ｐ極）との間に設けられ、現像スリーブ１３１上の現像剤を剥離する剥離磁極（Ｈ極）と、を有している。
本例では、吸着磁極（Ｐ極）、層規制磁極（Ｔ極）、現像磁極（Ｄ極）及び搬送磁極（Ｕ極）は隣り合う磁極が異なる極性に着磁され、剥離磁極（Ｈ極）が搬送磁極（Ｕ極）と同極性に着磁されている。
なお、現像スリーブ１３１には図示外の現像電圧が印加され、感光体３１と現像スリーブ１３１との間に所定の現像電界が形成されるようになっている。 -Typical elements of development equipment-
<Development roll>
As shown in FIG. 4, the developing roll 121 is provided with a cylindrical developing sleeve 131 made of aluminum, for example, and a fixed inside of the developing sleeve 131, and a plurality of (in this example, five) magnetic poles are arranged around it. The magnet roll 132 is provided. In this example, the magnetic pole of the magnet roll 132 is between the adsorption magnetic pole (P pole) that adsorbs the developer around the developing sleeve 131 and the layer regulation roll 124 provided at a portion corresponding to the layer regulation roll 124. And a layer regulating magnetic pole (T pole) capable of forming a magnetic force for regulating the developer layer thickness, and a development for developing an electrostatic latent image on the photoreceptor 31 provided at a development position facing the photoreceptor 31. A magnetic pole (D pole), a transport magnetic pole (U pole) provided on the downstream side in the rotation direction of the developing sleeve 131 with respect to the developing position, and between the transport magnetic pole (U pole) and the attracting magnetic pole (P pole) And a peeling magnetic pole (H pole) that peels off the developer on the developing sleeve 131.
In this example, the attracting magnetic pole (P pole), the layer regulating magnetic pole (T pole), the developing magnetic pole (D pole), and the transporting magnetic pole (U pole) are magnetized with different polarities, and the separation magnetic pole (H pole). Are magnetized in the same polarity as the carrier magnetic pole (U pole).
A developing voltage (not shown) is applied to the developing sleeve 131 so that a predetermined developing electric field is formed between the photosensitive member 31 and the developing sleeve 131.

＜撹拌搬送部材＞
本例では、現像容器１２０の現像剤収容室１３４は仕切り壁１３５を介して二室１３４ａ，１３４ｂに区分され、一方の現像剤収容室１３４ａには現像ロール１２１及び一方の撹拌搬送部材１２２が収容され、他方の現像剤収容室１３４ｂには他方の撹拌搬送部材１２３が収容されている。そして、仕切り壁１３５の長手方向の両端付近に通過口（図示せず）が開設され、現像剤収容室１３４の二室で対構成の撹拌搬送部材１２２，１２３が回転することで現像剤収容室１３４内の現像剤が二室に分かれて通過口を通じて循環して搬送するようになっている。
本例では、撹拌搬送部材１２２，１２３は、いずれも回転軸１３６の周囲に螺旋状羽根１３７を付した態様のものであり、一方の撹拌搬送部材１２２は現像ロール１２１の略直下に配設されており、撹拌搬送部材１２２で撹拌搬送されている現像剤が現像ロール１２１側に向けて供給されることから、現像ロール１２１への現像剤供給部材として機能している。 <Agitating and conveying member>
In this example, the developer accommodating chamber 134 of the developing container 120 is divided into two chambers 134a and 134b via a partition wall 135, and the developing roll 121 and one agitating and conveying member 122 are accommodated in one developer accommodating chamber 134a. Then, the other agitation transport member 123 is accommodated in the other developer accommodating chamber 134b. Passing ports (not shown) are opened near both ends in the longitudinal direction of the partition wall 135, and the developer conveying chambers 122 and 123 rotate in the two chambers of the developer accommodating chamber 134 so that the developer accommodating chamber is rotated. The developer in 134 is divided into two chambers and is circulated and conveyed through the passage port.
In this example, the agitating / conveying members 122 and 123 are both in a form in which a spiral blade 137 is attached around the rotation shaft 136, and one agitating / conveying member 122 is disposed substantially immediately below the developing roll 121. Since the developer stirred and conveyed by the agitating / conveying member 122 is supplied toward the developing roll 121, it functions as a developer supply member to the developing roll 121.

＜層規制ロール＞
本例では、層規制部材１２４は丸棒状の層規制ロールとして構成されており、層規制ロール１２４は現像容器１２０に予め形成された層規制受部１４０に受け止められ、その両端部を現像容器１２０の両側板に固定することで現像容器１２０に取り付けられている。
特に、本例では、層規制ロール１２４は磁性体にて構成されており、例えば層規制磁極（Ｔ極）の磁力によって磁化し、現像ロール１２１との間に所定の磁場を形成するようになっている。更に、本例では、層規制磁極（Ｔ極）は層規制ロール１２４と現像ロール１２１との最近接部位よりも現像スリーブ１３１の回転方向下流側に変位して配置されており、層規制磁極（Ｔ極）により層規制ロール１２４の磁化領域を広く確保し、層規制ロール１２４表面へのトナー付着を抑制し、層規制ロール１２４による現像剤の層規制作用域を十分に確保できるようになっている。
また、本例では、層規制ロール１２４は、現像ロール１２１の中心位置から鉛直方向に延びる鉛直線位置Ｌ３よりも感光体３１側に変位して配置されており、更に、撹拌搬送部材１２２の外周部のうち感光体３１側との水平方向距離が最も接近する部位での鉛直線位置Ｌ１よりも感光体３１側に変位して配置されている。
更に、本実施の形態では、図５に示すように、層規制ロール１２４の表面粗さδは算術平均粗さＲａで０．２以上に設定されている。 <Layer regulation roll>
In this example, the layer restricting member 124 is configured as a round bar-shaped layer restricting roll, and the layer restricting roll 124 is received by a layer restricting receiving portion 140 formed in advance in the developing container 120, and both ends thereof are developed in the developing container 120. It is attached to the developing container 120 by being fixed to both side plates.
In particular, in this example, the layer regulating roll 124 is made of a magnetic material, and is magnetized by, for example, the magnetic force of the layer regulating magnetic pole (T pole) to form a predetermined magnetic field with the developing roll 121. ing. Furthermore, in this example, the layer regulating magnetic pole (T pole) is disposed to be displaced downstream in the rotation direction of the developing sleeve 131 from the closest portion between the layer regulating roll 124 and the developing roll 121, and the layer regulating magnetic pole (T (T pole) ensures a wide magnetization region of the layer regulating roll 124, suppresses toner adhesion to the surface of the layer regulating roll 124, and sufficiently secures a layer regulating action area of the developer by the layer regulating roll 124. Yes.
Further, in this example, the layer regulating roll 124 is disposed so as to be displaced toward the photoconductor 31 side from the vertical line position L3 extending in the vertical direction from the center position of the developing roll 121, and further, the outer periphery of the stirring and conveying member 122 The vertical line position L1 at the part where the horizontal distance from the photosensitive member 31 side is closest is displaced to the photosensitive member 31 side.
Furthermore, in the present embodiment, as shown in FIG. 5, the surface roughness δ of the layer regulating roll 124 is set to 0.2 or more in terms of arithmetic average roughness Ra.

＜せき止めブロック＞
本例では、現像容器１２０のうち、層規制ロール１２４と撹拌搬送部材１２２との間にはせき止めブロック１５０が設けられている。
このせき止めブロック１５０は、非磁性の材料（例えばＡＢＳ樹脂）を用いて一体的に構成されており、現像容器１２０の底部に予め形成された例えば断面Ｌ字状のブロック受部１４１に支持され、図示外の止め具にて現像容器１２０の底部及び両側板に固定されている。
本例において、せき止めブロック１５０は撹拌搬送部材１２２で撹拌して搬送される現像剤のうち、層規制ロール１２４に直接向かうものをせき止める機能を有している。
具体的には、せき止めブロック１５０は、ブロック受部１４１に受け止められるブロック本体１５１を有し、このブロック本体１５１の層規制ロール１２４側には層規制ロール１２４の周囲が保持される湾曲状保持部１５２を一体的に突出して形成し、一方、ブロック本体１５１の撹拌搬送部材１２２側には撹拌搬送部材１２２から撹拌搬送される現像剤が現像ロール１２１の最下端付近に向けて案内する案内部１５５を一体的に形成したものである。 <Cough block>
In this example, a damming block 150 is provided between the layer regulating roll 124 and the stirring and conveying member 122 in the developing container 120.
The damming block 150 is integrally formed using a nonmagnetic material (for example, ABS resin), and is supported by a block receiving portion 141 having, for example, an L-shaped cross section formed in advance at the bottom of the developing container 120, It is fixed to the bottom and both side plates of the developing container 120 by a stopper (not shown).
In this example, the damming block 150 has a function of damping the developer that is directly agitated and conveyed by the agitating and conveying member 122 toward the layer regulating roll 124.
Specifically, the damming block 150 has a block main body 151 that is received by the block receiving portion 141, and a curved holding portion that holds the periphery of the layer restricting roll 124 on the layer restricting roll 124 side of the block main body 151. On the other hand, on the side of the stirring and conveying member 122 of the block main body 151, a guide portion 155 that guides the developer stirred and conveyed from the stirring and conveying member 122 toward the lowermost end of the developing roll 121. Are integrally formed.

ここで、案内部１５５は、ブロック本体１５１から撹拌搬送部材１２２の外周面のうち最も感光体３１側に接近した部位を通る鉛直線位置Ｌ１よりも撹拌搬送部材１２２側に突出して形成されており、撹拌搬送部材１２２の外周部を覆うように当該外周部に沿って湾曲する湾曲面１５６を有している。また、本例では、案内部１５５の突出端１５７は、撹拌搬送部材１２２の中心を通る鉛直線位置Ｌ２には至らない範囲で選定されている。これは、仮に、案内部１５５の突出端が鉛直線位置Ｌ２に至ってしまうと、撹拌搬送部材１２２の回転によって撹拌して搬送される現像剤が案内部１５５の湾曲面１５６に衝突して当該湾曲面１５６に沿って案内されるが、撹拌搬送部材１２２の最上端位置に至る場合には、撹拌搬送部材１２２による現像剤の搬送方向が略水平方向ないしは水平よりも斜め下方に向いてしまい、現像ロール１２１側に現像剤を供給し得ないことによる。
特に、本例では、案内部１５５の突出端１５７は、現像ロール１２１の中心を通る鉛直線位置Ｌ３の近傍に選定されており、更に、撹拌搬送部材１２２の回転軸１３６の周面のうち感光体３１との水平方向距離が最も接近した部位を通る鉛直線位置Ｌ４の近傍に選定されている。
また、本例では、案内部１５５の現像ロール１２１側面は、略水平方向に延びる水平面１５８と、この水平面１５８から層規制ロール１２４側に向かって斜め上方に傾斜する傾斜面１５９とを有している。
そして、案内部１５５の突出端１５７と層規制ロール１２４の現像ロール１２１との対向部位との間を結ぶ接線ｍは案内部１５５の水平面１５８に対して角度θ（例えば４０〜６０°）だけ傾斜配置されるようになっている。 Here, the guide portion 155 is formed to protrude toward the stirring and conveying member 122 from the vertical line position L1 passing through the portion of the outer peripheral surface of the stirring and conveying member 122 closest to the photoreceptor 31 side from the block main body 151. The curved surface 156 is curved along the outer peripheral portion so as to cover the outer peripheral portion of the stirring and conveying member 122. In this example, the protruding end 157 of the guide portion 155 is selected within a range that does not reach the vertical line position L2 that passes through the center of the stirring and conveying member 122. This is because, if the protruding end of the guide portion 155 reaches the vertical line position L2, the developer that is stirred and conveyed by the rotation of the stirring and conveying member 122 collides with the curved surface 156 of the guide portion 155, and the curved portion. Although guided along the surface 156, when reaching the uppermost end position of the agitating / conveying member 122, the developer conveying direction by the agitating / conveying member 122 is directed to the substantially horizontal direction or obliquely downward from the horizontal. This is because the developer cannot be supplied to the roll 121 side.
In particular, in this example, the protruding end 157 of the guide portion 155 is selected in the vicinity of the vertical line position L3 that passes through the center of the developing roll 121, and further, the photosensitive surface is exposed on the peripheral surface of the rotating shaft 136 of the agitating and conveying member 122. The horizontal distance from the body 31 is selected in the vicinity of the vertical line position L4 passing through the closest part.
Further, in this example, the side surface of the developing roll 121 of the guide portion 155 has a horizontal plane 158 extending in a substantially horizontal direction and an inclined plane 159 that is inclined obliquely upward from the horizontal plane 158 toward the layer regulating roll 124 side. Yes.
A tangent line m connecting the projecting end 157 of the guide part 155 and the facing part of the developing roller 121 of the layer regulating roll 124 is inclined by an angle θ (for example, 40 to 60 °) with respect to the horizontal plane 158 of the guide part 155. It is arranged.

−現像装置の作動−
次に、現像装置３４の作動について説明する。
今、現像容器１２０内の現像剤は撹拌搬送部材１２２，１２３によって撹拌搬送され、現像に供される上で十分な帯電特性を有している。
この状態において、撹拌搬送部材１２２は現像ロール１２１に向けて現像剤を供給するが、この現像剤の供給過程においては、現像剤はせき止めブロック１５０の案内部１５５によって案内された後に現像ロール１２１へと供給される。
一方、現像ロール１２１は、吸着磁極（Ｐ極）にて現像剤Ｇを吸着して保持し、現像スリーブ１３１の回転に伴って搬送される。この後、現像剤Ｇ１は撹拌搬送部材１２２からせき止めブロック１５０を介して供給された現像剤Ｇ２と合流し、合流した現像剤Ｇ３が層規制ロール１２４を経て層規制され、予め決められた搬送量の現像剤が現像位置へと搬送される。 -Operation of the developing device-
Next, the operation of the developing device 34 will be described.
Now, the developer in the developing container 120 is agitated and conveyed by the agitating / conveying members 122 and 123, and has sufficient charging characteristics for use in development.
In this state, the agitating / conveying member 122 supplies the developer toward the developing roll 121. In the developer supplying process, the developer is guided to the developing roll 121 after being guided by the guide portion 155 of the blocking block 150. Supplied with.
On the other hand, the developing roll 121 attracts and holds the developer G with the attracting magnetic pole (P pole), and is conveyed along with the rotation of the developing sleeve 131. Thereafter, the developer G1 merges with the developer G2 supplied from the agitating and conveying member 122 via the damming block 150, and the merged developer G3 is subjected to layer regulation via the layer regulating roll 124, and a predetermined conveyance amount. Developer is conveyed to the developing position.

＜せき止めブロックの作用＞
このような現像装置３４の作動において、せき止めブロック１５０の作用について詳述すると以下の通りである。
（１）現像剤のせき止め作用
撹拌搬送部材１２２にて撹拌して搬送された現像剤はせき止めブロック１５０のブロック本体１５１及び案内部１５５にせき止められ、現像剤のうち層規制ロール１２４へ直接的に向かうものは除去される。
（２）現像剤の案内作用
せき止めブロック１５０は、せき止めた現像剤を案内部１５５にて案内し、現像ロール１２１へと案内する。
このとき、撹拌搬送部材１２２にて撹拌搬送された現像剤は、せき止めブロック１５０の案内部１５５の湾曲面１５６に沿って案内され、案内部１５５の突出端１５７を乗り越えた位置で、現像ロール１２１側に向かって撹拌搬送部材１２２により押し上げられる。
特に、本例では、案内部１５５の突出端１５７が撹拌搬送部材１２２の回転軸１３６周面の鉛直線位置Ｌ４の近傍に配置されていることから、撹拌搬送部材１２２の螺旋状羽根１３７にて搬送されている略全ての現像剤が案内部１５５を乗り越えた段階で現像ロール１２１側へと供給される点で好ましい。更に、本例では、案内部１５５を乗り越えた現像剤Ｇ２は現像ロール１２１の吸着磁極（Ｐ極）に吸着後に搬送されている現像剤Ｇ１と合流し、合流した現像剤Ｇ３が層規制ロール１２４へと向かう。 <Operation of damming block>
The operation of the damming block 150 in the operation of the developing device 34 will be described in detail as follows.
(1) Damping action of developer The developer stirred and conveyed by the agitating and conveying member 122 is blocked by the block main body 151 and the guide portion 155 of the blocking block 150, and directly to the layer regulating roll 124 of the developer. Anything going is removed.
(2) Guide Action of Developer The damming block 150 guides the damped developer by the guide portion 155 and guides it to the developing roll 121.
At this time, the developer agitated and conveyed by the agitating and conveying member 122 is guided along the curved surface 156 of the guide portion 155 of the anti-blocking block 150, and at the position over the protruding end 157 of the guide portion 155. It is pushed up by the agitating and conveying member 122 toward the side.
In particular, in this example, since the protruding end 157 of the guide portion 155 is disposed in the vicinity of the vertical line position L4 on the circumferential surface of the rotation shaft 136 of the stirring and conveying member 122, the spiral blade 137 of the stirring and conveying member 122 It is preferable in that almost all the developer being conveyed is supplied to the developing roll 121 side when it has passed over the guide portion 155. Furthermore, in this example, the developer G2 that has passed over the guide portion 155 merges with the developer G1 conveyed after being attracted to the attracting magnetic pole (P pole) of the developing roll 121, and the joined developer G3 is the layer regulating roll 124. Head to.

（３）層規制ロール１２４の直前部における現像剤挙動
前述したように、現像ロール１２１上には合流した現像剤Ｇ３が現像スリーブ１３１の移動速度に相当する速い流速領域αで移動する。
これに対し、層規制ロール１２４の入口直前では層規制ロール１２４の周囲に滞留する現像剤により遅い流速領域βが生ずる。
そして、現像剤の流速の速い領域αと流速の遅い領域βとが接触し合う領域γでは渦状の領域γが生ずる。
このとき、層規制ロール１２４の入口直前の遅い流速領域βの現像剤は渦状の領域γへと引き込まれることから、層規制ロール１２４の周辺に現像剤が滞留したままの状態は回避される。このため、滞留した現像剤のトナーが層規制ロール１２４の入口直前に経時的に付着する事態は回避される。
一方、現像剤の渦状の領域γは、現像ロール１２１に保持される速い流速領域αの現像剤Ｇ３に対して現像剤Ｇの搬送力が抑制されるブレーキ作用につながり、その分、現像剤の搬送量を下げる要因にはなるが、渦状の領域γの現像剤の一部が速い流速領域αの現像剤Ｇに引き込まれることから、現像剤の搬送量は補填されるものと推測される。 (3) Developer Behavior at the Immediate Front of the Layer Regulating Roll 124 As described above, the joined developer G3 moves on the developing roll 121 in a high flow velocity region α corresponding to the moving speed of the developing sleeve 131.
On the other hand, immediately before the entrance of the layer regulating roll 124, the developer staying around the layer regulating roll 124 causes a slow flow velocity region β.
Then, in the region γ where the region α where the flow rate of the developer is fast and the region β where the flow rate is slow contact, a spiral region γ is generated.
At this time, the developer in the slow flow velocity region β immediately before the entrance of the layer regulating roll 124 is drawn into the spiral region γ, so that the state where the developer remains around the layer regulating roll 124 is avoided. Therefore, it is possible to avoid a situation in which the staying developer toner adheres with time immediately before the entrance of the layer regulating roll 124.
On the other hand, the spiral region γ of the developer leads to a braking action in which the conveying force of the developer G is suppressed with respect to the developer G3 in the fast flow velocity region α held by the developing roll 121. Although this is a factor for reducing the transport amount, a part of the developer in the spiral region γ is drawn into the developer G in the fast flow velocity region α, so that the developer transport amount is estimated to be compensated.

＜層規制ロールの作用＞
層規制ロール１２４は、図７（ａ）に示すように、現像ロール１２１の層規制磁極（Ｔ極）、吸着磁極（Ｐ極）とで形成される磁場によって磁化され、現像ロール１２１との間に所定の磁力線分布からなる磁力を作用させる。
このとき、図６（ｂ）に示すように、層規制ロール１２４と現像ロール１２１との最近接部における磁力Ｍ（Ｔ）は、層規制磁極（Ｔ極）の磁束密度に応じて増減するが、この磁力Ｍ（Ｔ）が予め決められた値（例えば５０ｍＴ以上）であれば、現像剤Ｇによる磁気ブラシＢＨの腰の強さが大きく設定される。
このため、例えば層規制ロール１２４にトナーによるトナー痕１６０が経時付着したとしても、現像剤Ｇによる腰の強い磁気ブラシＢＨによって付着したトナー痕１６０が掻き取られ、層規制ロール１２４が清掃される。 <Action of layer regulating roll>
The layer regulating roll 124 is magnetized by a magnetic field formed by the layer regulating magnetic pole (T pole) and the attracting magnetic pole (P pole) of the developing roll 121 as shown in FIG. A magnetic force having a predetermined magnetic field line distribution is applied to.
At this time, as shown in FIG. 6B, the magnetic force M (T) at the closest portion between the layer regulating roll 124 and the developing roll 121 increases or decreases according to the magnetic flux density of the layer regulating magnetic pole (T pole). If the magnetic force M (T) is a predetermined value (for example, 50 mT or more), the waist strength of the magnetic brush BH by the developer G is set large.
For this reason, for example, even if the toner trace 160 due to toner adheres to the layer regulation roll 124 over time, the toner trace 160 adhered by the stiff magnetic brush BH due to the developer G is scraped off and the layer regulation roll 124 is cleaned. .

◎比較の形態１
次に、本実施の形態に係る現像装置の性能を評価する上で、比較の形態１に係る現像装置について説明する。
比較の形態１に係る現像装置３４’は、図７に示すように、実施の形態１と略同様な現像ロール１２１、撹拌搬送部材１２２，１２３及び層規制ロール１２４を備えているが、実施の形態１と異なり、せき止めブロック１５０（図４参照）を備えていない。
本比較の形態にあっては、現像ロール１２１は、吸着磁極（Ｐ極）にて現像剤Ｇ１を保持し、現像スリーブ１３１の移動に伴って現像剤Ｇ１を保持搬送する。
また、撹拌搬送部材１２２は現像剤Ｇ２を撹拌搬送した後に現像ロール１２１側に供給する。
このとき、撹拌搬送部材１２２と層規制ロール１２４との間にせき止めブロック１５０が設けられていないため、撹拌搬送部材１２２からの現像剤Ｇの一部が直接層規制ロール１２４に向かって供給される。このため、層規制ロール１２４の入口直前の領域Ｗでは、層規制ロール１２４に現像剤Ｇ２の一部が強く衝突する事態が経時的に起こり、この現像剤Ｇ２の一部のたたきつけの繰り返しに伴って層規制ロール１２４にはトナーの付着によるトナー痕が層規制ロール１２４の軸方向に沿って形成される事態が見られる。
このようなトナー痕が層規制ロール１２４に経時的に付着すると、これに伴って、現像ロール１２１上の現像剤Ｇ１が層規制ロール１２４を通過するに際し、現像ロール１２１上の現像剤が層規制ロール１２４にて層厚を規制するとき、層規制ロール１２４のトナー痕が現像剤の層規制動作を損ない、トナー痕の存在する部位にて現像剤の搬送量を低下させる懸念がある。 ◎ Comparison form 1
Next, when evaluating the performance of the developing device according to the present embodiment, the developing device according to Comparative Embodiment 1 will be described.
As shown in FIG. 7, the developing device 34 ′ according to the comparative embodiment 1 includes a developing roll 121, agitating and conveying members 122 and 123, and a layer regulating roll 124 that are substantially the same as those of the first embodiment. Unlike the first embodiment, the damming block 150 (see FIG. 4) is not provided.
In this comparative embodiment, the developing roll 121 holds the developer G1 with the attracting magnetic pole (P pole), and holds and conveys the developer G1 as the developing sleeve 131 moves.
The agitating and conveying member 122 supplies the developer G2 to the developing roll 121 side after agitating and conveying it.
At this time, since the damming block 150 is not provided between the stirring and conveying member 122 and the layer regulating roll 124, a part of the developer G from the stirring and conveying member 122 is directly supplied toward the layer regulating roll 124. . For this reason, in the region W immediately before the entrance of the layer regulating roll 124, a situation occurs in which a part of the developer G2 strongly collides with the layer regulating roll 124 with time, and with the repeated knocking of a part of the developer G2. Thus, it can be seen that toner marks are formed on the layer regulating roll 124 along the axial direction of the layer regulating roll 124 due to toner adhesion.
When such toner marks adhere to the layer regulation roll 124 over time, the developer G1 on the development roll 121 passes through the layer regulation roll 124 and the developer on the development roll 121 becomes layer regulation. When the layer thickness is regulated by the roll 124, there is a concern that the toner mark on the layer regulating roll 124 impairs the layer regulating operation of the developer, and the transport amount of the developer is reduced at the site where the toner mark exists.

◎実施例１
実施例１は実施の形態１に係る現像装置を具現化したもので、図８に示すように、せき止めブロック（図８ではBlock（BL）と表記）を設置し、層規制磁極（Ｔ極）を４５ｍＴ、吸着磁極（Ｐ）極を６０ｍＴとした。
◎実施例２
実施例２は実施の形態１に係る現像装置を具現化したもので、図８に示すように、せき止めブロックを設置し、層規制磁極（Ｔ極）を５８ｍＴ、吸着磁極（Ｐ）極を６０ｍＴとした。なお、層規制磁極（Ｔ極）は層規制ロールと現像ロールとの最近接位置に対し感光体側に１０度変位したものとした。以下の実施例２，比較例１〜３についても同様である。
◎比較例１
比較例１は比較の形態１に係る現像装置（但し、磁極数は４）を具現化したもので、図８に示すように、せき止めブロックを用いずに、層規制磁極（Ｔ極）を５５ｍＴ、吸着磁極（Ｐ）極を３０ｍＴとした。
◎比較例２
比較例２は比較の形態１に係る現像装置（磁極数は５）を具現化したもので、図８に示すように、せき止めブロックを用いずに、層規制磁極（Ｔ極）を４５ｍＴ、吸着磁極（Ｐ）極を６０ｍＴとした。
◎比較例３
比較例３は比較の形態１に係る現像装置（磁極数は５）を具現化したもので、図８に示すように、せき止めブロックを用いずに、層規制磁極（Ｔ極）を７５ｍＴ、吸着磁極（Ｐ）極を６０ｍＴとした。 Example 1
Example 1 is an embodiment of the developing device according to the first embodiment. As shown in FIG. 8, a blocking block (indicated as Block (BL) in FIG. 8) is installed, and a layer regulating magnetic pole (T pole) is provided. Was 45 mT, and the attracting magnetic pole (P) pole was 60 mT.
Example 2
Example 2 is an embodiment of the developing device according to the first embodiment. As shown in FIG. 8, a blocking block is installed, the layer regulating magnetic pole (T pole) is 58 mT, and the attracting magnetic pole (P) pole is 60 mT. It was. The layer-regulating magnetic pole (T-pole) was displaced 10 degrees toward the photoreceptor with respect to the closest position between the layer-regulating roll and the developing roll. The same applies to Example 2 and Comparative Examples 1 to 3 below.
◎ Comparative Example 1
Comparative Example 1 embodies the developing device according to Comparative Embodiment 1 (however, the number of magnetic poles is 4). As shown in FIG. 8, the layer regulating magnetic pole (T pole) is set to 55 mT without using a blocking block. The adsorption magnetic pole (P) pole was set to 30 mT.
◎ Comparative Example 2
Comparative Example 2 embodies the developing device (the number of magnetic poles is 5) according to Comparative Example 1. As shown in FIG. 8, the layer-regulating magnetic pole (T pole) is attracted by 45 mT without using the blocking block. The magnetic pole (P) pole was 60 mT.
◎ Comparative Example 3
Comparative Example 3 embodies the developing device (the number of magnetic poles is 5) according to Comparative Example 1. As shown in FIG. 8, the layer-regulating magnetic pole (T pole) is adsorbed to 75 mT without using a blocking block. The magnetic pole (P) pole was 60 mT.

実施例１，２によれば、図９（ａ）のＩ（実施例１），ＩＩ（実施例２）の領域及び同図（ｂ）に示すように、層規制ロールに形成されるトナー痕１６０の幅ｗ０は０．５ｍｍ以下に抑えられる。
そして、本例では、層規制ロールによる層規制動作に伴う現像剤搬送量（ＭＯＳ：Mass on the sleeveの略）に大きさ差は見られなかった。
ここで、層規制磁極（Ｔ極）を５０ｍＴ、好ましくは５５ｍＴ以上にした場合に、これ未満の態様に比べて、トナー痕１６０の幅が良好に少なく抑えられ、これに伴って現像剤搬送量（ＭＯＳ）が安定化させられることが理解される。
これに対し、比較例１〜３、例えば比較例２によれば、図９（ａ）のＩＩの領域及び動ず（ｃ）に示すように、層規制ロールに形成されるトナー痕１６０の幅ｗ１は１ｍｍ程度のものが生ずる。
このようなトナー痕１６０が生ずる場合には、図８に示すように、層規制ロールによる層規制動作に伴う現像剤搬送量（ＭＯＳ）には１００〜２００ｇ／ｍ^２の程度の差が見られた。 According to Examples 1 and 2, as shown in the regions I (Example 1) and II (Example 2) of FIG. 9A and the toner mark formed on the layer regulating roll as shown in FIG. The width w0 of 160 is suppressed to 0.5 mm or less.
In this example, there was no difference in the developer conveyance amount (abbreviation of MOS: Mass on the sleeve) accompanying the layer regulation operation by the layer regulation roll.
Here, when the layer regulating magnetic pole (T pole) is set to 50 mT, preferably 55 mT or more, the width of the toner mark 160 is suppressed to a smaller value than that of the mode less than this, and the developer transport amount is accordingly increased. It is understood that (MOS) can be stabilized.
On the other hand, according to Comparative Examples 1 to 3, for example, Comparative Example 2, the width of the toner mark 160 formed on the layer regulating roll as shown in the region II in FIG. 9A and the movement (c). w1 is about 1 mm.
When such a toner mark 160 occurs, as shown in FIG. 8, a difference of about 100 to 200 g / m ² is observed in the developer conveyance amount (MOS) accompanying the layer regulating operation by the layer regulating roll. It was.

また、実施例１と比較例３とを用い、現像装置の経時使用（作像枚数ｐｖに相当）に伴う現像剤搬送量（ＭＯＳ）の変化を調べることにした。本例では、現像ロールのうち長手方向の奥側領域に所定の画像を繰り返し形成し、当該領域での現像剤搬送量の変化を調べた。
結果を図１０（ａ）（ｂ）に示す。
図１０（ａ）は実施例２の結果を示し、現像装置を経時使用しても、現像剤搬送量（ＭＯＳ）は約６００ｇ／ｍ^２以上確保されていることが理解される。
また、図１０（ｂ）は比較例３の結果を示し、現像剤搬送量（ＭＯＳ）は、初期において約４７０ｇ／ｍ^２程度であったものが、現像装置を経時使用した場合、約３５０ｇ／ｍ^２程度まで低下していることが確認された。
このように、実施例２と比較例３とを対比すると、現像剤搬送量（ＭＯＳ）を安定化させるにはせき止めブロックを用いることが有効であることが理解される。 Further, using Example 1 and Comparative Example 3, it was decided to examine the change in the developer conveyance amount (MOS) with the use of the developing device over time (corresponding to the number of image forming sheets pv). In this example, a predetermined image was repeatedly formed on the inner side of the developing roll in the longitudinal direction, and changes in the developer conveyance amount in the region were examined.
The results are shown in FIGS. 10 (a) and 10 (b).
FIG. 10 (a) shows the result of Example 2, and it is understood that the developer transport amount (MOS) is secured at about 600 g / m ² or more even when the developing device is used over time.
FIG. 10B shows the result of Comparative Example 3. The developer transport amount (MOS) was about 470 g / m ² in the initial stage, but it was about 350 g / m when the developing device was used over time. It was confirmed that it had dropped to about m ² .
Thus, when Example 2 and Comparative Example 3 are compared, it is understood that the use of a damming block is effective for stabilizing the developer conveyance amount (MOS).

１…現像剤保持体，２…現像回転体，３…磁石部材，４（４ａ〜４ｅ）…磁極，４ｂ…層規制磁極，５…現像剤供給部材，６…撹拌搬送部材，７…層規制部材，７ａ…曲面部，８…せき止め部材，９…案内部，１１…像保持体，１２…現像装置，１３…現像容器 DESCRIPTION OF SYMBOLS 1 ... Developer holding body, 2 ... Development rotary body, 3 ... Magnet member, 4 (4a-4e) ... Magnetic pole, 4b ... Layer regulation magnetic pole, 5 ... Developer supply member, 6 ... Agitation conveyance member, 7 ... Layer regulation Member 7a ... Curved surface part 8 Damping member 9 Guide part 11 Image carrier 12 Development device 13 Developer container

Claims

A hollow developing rotator, and a magnet member that is fixedly provided in the developing rotator and has a plurality of magnetic poles arranged around it, and rotating the developing rotator to counteract the magnetic force generated by the magnet member. A developer holding body for holding a developer containing toner and magnetic carrier on the developing rotator,
A developer supply member provided below the developer holder, and supplying the developer to the developer holder;
A curved surface portion having an arcuate cross section that protrudes toward the developer holding body and is opposed to the developer holding body through a gap so as to be in non-contact with the developer holding body, and is held on the developer holding body. A layer regulating member that regulates the layer thickness of the developer;
A dam member provided between the layer regulating member and the developer supplying member, and blocking a path toward the layer regulating member among the developer supplied from the developer supplying member;
The dam member protrudes from the vertical line position passing through the layer regulating member side end of the outer periphery of the developer supply member to the developer supply member side and reaches the vertical line position passing through the center of the developer supply member. A guide portion that covers the outer peripheral portion of the developer supply member within a range and guides the clogged developer to the developer holding body side, and the developer holding body side of the guide portion includes the layer regulating member from the layer regulating member. A developing apparatus, characterized in that a developing surface is formed to protrude upstream in the transport direction of the developer by the developer holder and to face the developer holder .

The developing device according to claim 1,
The developing device according to claim 1, wherein the opposing surface has an inclined surface that is inclined obliquely upward from a horizontal plane toward the layer regulating member side.

The developing device according to claim 1 or 2 ,
The developing device according to claim 1, wherein the guide portion is formed in a range not exceeding a vertical line position passing through a center of the developer holder.

In the developing device according to any one of claims 1 to 3 ,
The developing device, wherein the developer holding body includes a layer regulating magnetic pole at a portion corresponding to the layer regulating member, and a magnetic force acting on the layer regulating member by the layer regulating magnetic pole is 50 mT or more.

In the developing device according to any one of claims 1 to 4 ,
The developing device according to claim 1, wherein the curved surface portion of the layer regulating member has a surface roughness Ra of 0.2 or more.

An image carrier for holding an electrostatic latent image;
An image forming apparatus characterized by comprising a developing device according to any one of claims 1 to 5 for developing an electrostatic latent image on the image carrier by the corresponding developer.