JP2011141368A

JP2011141368A - Developing apparatus, process cartridge, and image forming apparatus

Info

Publication number: JP2011141368A
Application number: JP2010001174A
Authority: JP
Inventors: Yoshio Hattori; 服部良雄; Yoshiyuki Fukuda; 福田善行; Akira Asami; 浅見彰; Katsumi Masuda; 増田克己; Takamasa Ozeki; 尾関孝将; Keiichi Yoshida; 吉田圭一; Nobuyuki Taguchi; 田口信幸; Toshiki Hayashi; 林俊樹; Yuki Sato; 佐藤裕貴
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 2010-01-06
Filing date: 2010-01-06
Publication date: 2011-07-21

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing apparatus, process cartridge, and image forming apparatus where the dispersibility of supply toner is high and occurrence of scumming or toner scattering is suppressed. <P>SOLUTION: This developing apparatus 20 has a doctor blade 25 under a developing roller 22, and circulates a developer in one direction. The rotating direction of a first conveyance screw 28 is set to be the same as the rotating direction of the developing roller 22, and the rotating direction of a second conveyance screw 29 is set to be opposite to the rotating direction of the developing roller 22. On the other end side of a stirring conveying chamber 27, a toner supply port 30 is disposed on an upstream side in the developer conveying direction rather than a delivery section 31. A paddle 34 for feeding the developer upward is disposed at a position facing the delivery section 31 of the first conveyance screw 28. A projecting shape 36 is formed on the lower wall between a developing conveying chamber 26 and the stirring conveying chamber 27 in the delivery section 31. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、トナーとキャリアからなる現像剤を用いる現像装置と、該現像装置を用いるプロセスカートリッジ及び複写機、プリンタ、ファクシミリまたはそれらの少なくとも２つの機能を有する複合機等の画像形成装置に関するものである。 The present invention relates to a developing device using a developer composed of toner and a carrier, a process cartridge using the developing device, and an image forming apparatus such as a copying machine, a printer, a facsimile, or a multifunction machine having at least two functions thereof. is there.

上記形式の画像形成装置において、近年、トナーとキャリアからなる２成分現像方式の現像装置を採用するのが主流となっている。この種の現像装置の多くは特許文献２の図１９等に記載されているように、水平に配置した２のスクリューを並べて構成している。この２本のスクリューのうち感光体ドラムに近い方に位置する第１のスクリューは、現像剤担持体（現像スリーブ）に現像剤を供給し、現像部を通過した後の現像剤を回収するために用いられる。また、第２の搬送スクリューは、現像スリーブから回収された現像剤と新しく補給された現像剤とを混合撹拌するために用いられる。 In the image forming apparatus of the above type, in recent years, it has become the mainstream to employ a two-component developing type developing device composed of toner and carrier. Many developing devices of this type are configured by arranging two screws arranged horizontally as described in FIG. Of these two screws, the first screw located closer to the photosensitive drum supplies the developer to the developer carrying member (developing sleeve) and collects the developer after passing through the developing section. Used for. The second conveying screw is used for mixing and stirring the developer collected from the developing sleeve and the newly supplied developer.

一方、近年、複写機、プリンタ等の電子写真方式を用いた画像形成装置においては、省スペースを達成するために装置本体の小型化の要求が大きくなっており、特に、フルカラー方式の画像形成装置においては、現像装置を複数用いるため、モノクロの装置に比べて大型化するが、それを少しでも小型化することが要望されている。 On the other hand, in recent years, in an image forming apparatus using an electrophotographic system such as a copying machine or a printer, there has been an increasing demand for downsizing the apparatus main body in order to achieve space saving. However, since a plurality of developing devices are used, the size of the developing device is larger than that of a monochrome device. However, it is desired to reduce the size as much as possible.

この要望に答えるため、特許文献１には現像剤を撹拌・搬送し、現像容器内を循環させる循環手段である２本の搬送スクリューが上下に配置した現像装置が提案されている。この現像装置は、現像剤を収容した現像容器を備え、現像容器の感光体ドラムと対面した開口部に現像剤担持体である現像スリーブを有している。そして、現像容器内の開口部との反対側には隔壁によって区画された現像搬送室と撹拌搬送室が上下に形成されており、これらの現像搬送室と撹拌搬送室内には、循環手段である第１及び第２の搬送スクリューがそれぞれ設置されている。第１の搬送スクリューは現像搬送室内の現像剤を搬送し、また、第２の搬送スクリューはトナー補給口から撹拌搬送室内に第２の搬送スクリューの上流側に供給されるトナーと撹拌搬送室内に既にある現像剤とを撹拌しながら搬送し、現像剤のトナー濃度を均一化する。 In order to meet this demand, Patent Document 1 proposes a developing device in which two conveying screws, which are circulation means for agitating and conveying the developer and circulating in the developing container, are arranged up and down. This developing device includes a developing container containing a developer, and has a developing sleeve as a developer carrying member at an opening facing the photosensitive drum of the developing container. A developing transport chamber and a stirring transport chamber partitioned by a partition are formed vertically on the side opposite to the opening in the developing container. The developing transport chamber and the stirring transport chamber are circulating means. First and second conveying screws are respectively installed. The first conveying screw conveys the developer in the developing and conveying chamber, and the second conveying screw is supplied from the toner replenishing port into the agitating and conveying chamber and the toner supplied to the upstream side of the second conveying screw and the agitating and conveying chamber. The existing developer is conveyed while stirring to make the toner density of the developer uniform.

以上説明したような縦撹拌型の現像装置は、現像搬送室と撹拌搬送室とが鉛直方向上下に配置されているため、その水平方向の占有スペースが小さくて済み、例えば複数の現像装置を水平方向に並列搭載するタンデム方式等のカラー画像形成装置において装置の小型化に寄与する等の利点が得られる。 In the vertical agitation type developing device as described above, the development conveyance chamber and the agitation conveyance chamber are arranged vertically above and below, so that the space occupied in the horizontal direction can be small. For example, a plurality of development devices can be arranged horizontally. In a color image forming apparatus such as a tandem system that is mounted in parallel in the direction, advantages such as contributing to downsizing of the apparatus are obtained.

かかる縦撹拌型の現像装置における現像剤の流れについて説明すると、トナー消費に伴う補給トナーは撹拌搬送室の一部に設けられたトナー補給口から装置内に補給される。補給されたトナーは撹拌搬送室内に既存の現像剤とともに、第２の搬送スクリューによって撹拌・混合され、現像剤のトナー濃度が均一化される。トナー濃度が均一化された現像剤は、撹拌搬送室の現像剤搬送方向下流の送り込み部から現像搬送室に落下して移動し、第１の搬送スクリューによって搬送されつつ、内部に固定配置された磁気ロールの磁極により現像スリーブの全長に亘って汲み上げられる。汲み上げられた現像剤は現像剤規制部材によって付着量が規制され、最終的に現像スリーブに付着して現像領域に達しなかった現像剤は現像搬送室の現像剤搬送方向下流の受け渡し部から撹拌搬送室に戻される。また、現像スリーブに付着して現像領域に達しったが像担持体に移行せずに残留した現像剤は、剤離れ磁極によって現像スリーブから離れ上部の撹拌搬送室に戻される。 The flow of the developer in the vertical stirring type developing device will be described. Supply toner accompanying toner consumption is supplied into the device from a toner supply port provided in a part of the stirring conveyance chamber. The replenished toner is agitated and mixed by the second conveying screw together with the existing developer in the agitating and conveying chamber, and the toner concentration of the developer is made uniform. The developer having a uniform toner concentration is dropped and moved from the feeding portion of the agitating and conveying chamber downstream in the developer conveying direction to the developing and conveying chamber, and is fixedly arranged inside while being conveyed by the first conveying screw. It is pumped over the entire length of the developing sleeve by the magnetic pole of the magnetic roll. The amount of the developer that has been pumped up is regulated by the developer regulating member, and the developer that finally adheres to the developing sleeve and does not reach the development area is agitated and conveyed from the delivery section downstream in the developer conveying direction of the developer conveying chamber. Returned to the room. Further, the developer that has adhered to the developing sleeve and has reached the developing area but has not moved to the image carrier is separated from the developing sleeve by the agent separating magnetic pole and returned to the upper agitating and conveying chamber.

かくして、撹拌搬送室にはその上流側で現像搬送室からの受け渡しと、現像スリーブのほぼ全長からの剤離れによる戻しと、消費量に相当する量のトナー補給とがある。これらのトナーや現像剤が集まる撹拌搬送室内では、トナーの比重が現像剤よりも軽いので、新しく補給されたトナーが現像剤の上部に浮いて移動する、所謂上滑りという現象が発生してしまうと、トナー濃度が不均一になり、地汚れやトナー飛散を招くことがあった。さらに、新たに補給したトナーが撹拌搬送室をある程度纏まったまま分散されずに搬送されると、撹拌不足になり、撹拌不良まま現像搬送室に送り込まれるため、トナー濃度が安定せず上記した地汚れやトナー飛散の原因になった。 Thus, the agitating / conveying chamber includes a delivery from the developing / conveying chamber on the upstream side thereof, a return by separating the agent from almost the entire length of the developing sleeve, and a toner replenishment corresponding to the consumption amount. Since the specific gravity of the toner is lighter than that of the developer in the agitating and conveying chamber in which these toners and developers are collected, a so-called upslip phenomenon occurs in which newly supplied toner floats and moves above the developer. In some cases, the toner density becomes non-uniform, resulting in scumming or toner scattering. Furthermore, if newly replenished toner is transported without being dispersed to a certain extent in the agitation transport chamber, the agitation will be insufficient and the toner will not be stabilized and the toner density will not be stabilized. Caused dirt and toner scattering.

本発明は、上記した従来の問題を解消し、補給トナーの分散性が良好で、十分なる撹拌が可能となって地汚れやトナー飛散の発生を抑えられる、現像装置、プロセスカートリッジ及び画像形成装置を提供することを目的としている。 The present invention solves the above-described conventional problems, has a good replenisher toner dispersibility, can be sufficiently stirred, and can suppress the occurrence of background contamination and toner scattering, and a developing device, a process cartridge, and an image forming apparatus The purpose is to provide.

上記課題を解決するため、本発明は、静電潜像を担持する像担持体と対向配置され、磁界発生手段を内包する現像剤担持体と、該現像剤担持体の下方に位置し、供給するトナー及びキャリアを有する現像剤を当該現像剤担持体の回転軸線方向に沿って搬送する第１搬送部材を備えた現像搬送室と、前記現像剤担持体の下方に対向するように配設され、前記現像剤担持体に担持された現像剤の量を規制する現像剤規制部材と、前記像担持体と対向位置を過ぎた位置で、前記現像剤担持体上から離脱した現像剤を回収し、前記現像剤担持体の回転軸線方向に沿って撹拌しつつ前記第１搬送部材と逆方向に搬送する第２搬送部材を備えた撹拌搬送室とを有し、前記現像搬送室と前記撹拌搬送室とが隔壁で仕切られているとともに、前記撹拌搬送室が前記現像搬送室より上方に配置されており、前記撹拌搬送室の現像剤搬送方向下流側に前記現像搬送室へ現像剤を送り込む送り込み部が設けられ、前記現像搬送室の送り込み部よりも現像剤搬送方向上流側に前記撹拌搬送室へ現像剤を受け渡す受け渡し部が設けられている現像装置において、前記第１搬送部材の回転方向が前記現像剤担持体の回転方向と同一方向で、前記第２搬送部材の回転方向が前記現像剤担持体の回転方向と反対方向に設定されているとともに、前記撹拌搬送室には前記受け渡し部よりも現像剤搬送方向上流側にトナー補給部が設けられ、前記第１搬送部材の前記受け渡し部に対向する位置には、現像剤を上方へ送り出す部材が設けられているとともに、前記受け渡し部における前記現像搬送室と前記撹拌搬送室との間の下壁に凸形状が形成されていることを特徴とする現像装置を提案する。 In order to solve the above-described problems, the present invention provides a developer carrier that is disposed opposite to an image carrier that carries an electrostatic latent image and contains magnetic field generating means, and is located below the developer carrier and is supplied A developer carrying chamber having a first carrying member for carrying a developer having toner and a carrier to be conveyed along the rotation axis direction of the developer carrying body, and disposed below the developer carrying body. A developer regulating member that regulates the amount of developer carried on the developer carrying body, and a developer separated from the developer carrying body at a position past the image carrying body. And a stirring and conveying chamber having a second conveying member that conveys in the direction opposite to the first conveying member while stirring along the rotation axis direction of the developer carrying member, and the developing and conveying chamber and the agitating and conveying The stirring chamber is partitioned by a partition wall, The developer transport chamber is disposed above the developer transport chamber, and is provided with a feed portion that feeds the developer into the developer transport chamber on the downstream side in the developer transport direction of the agitating transport chamber, and is more developer than the feed portion of the developer transport chamber. In the developing device in which a delivery unit for delivering the developer to the agitation transport chamber is provided upstream in the transport direction, the rotation direction of the first transport member is the same as the rotation direction of the developer carrier, and the first 2 The rotation direction of the conveying member is set in the direction opposite to the rotation direction of the developer carrying member, and the agitation conveying chamber is provided with a toner replenishing portion upstream of the delivery portion with respect to the developer conveying direction, A member that feeds the developer upward is provided at a position facing the transfer portion of the first transfer member, and between the developing transfer chamber and the agitating transfer chamber in the transfer portion. Suggest developing apparatus is characterized in that convex shape is formed on the lower wall.

なお、本発明は、前記上方へ送り出す部材がパドルであり、該パドルが前記第１搬送部材の回転軸に等角度ごとに複数枚設けられていると有利である。 In the present invention, it is advantageous that the member sent out upward is a paddle, and a plurality of the paddles are provided on the rotating shaft of the first transport member at equal angles.

さらに、本発明は、前記凸形状は前記第１搬送部材と前記第２搬送部材の回転軸線を結ぶ直線よりも下側で、前記現像搬送室と前記撹拌搬送室を遮ると有利である。
さらにまた、本発明は、前記受け渡し部における、前記現像搬送室と前記撹拌搬送室の境界部の上壁が前記第１搬送部材及び前記第２搬送部材の回転軸線を結ぶ直線とはほぼ平行な直線であると有利である。 Further, according to the present invention, it is advantageous that the convex shape is below the straight line connecting the rotation axes of the first conveyance member and the second conveyance member, and the developing conveyance chamber and the agitation conveyance chamber are blocked.
Furthermore, the present invention is such that the upper wall of the boundary between the developing conveyance chamber and the agitation conveyance chamber in the transfer section is substantially parallel to a straight line connecting the rotation axes of the first conveyance member and the second conveyance member. A straight line is advantageous.

また、上記課題を解決するため、本発明は、画像形成装置の装置本体に対して着脱自在に設置されるプロセスカートリッジであって、請求項１ないし請求項４の何れかに記載の現像装置と前記像担持体とが一体化されたことを特徴とするプロセスカートリッジを提案する。 In order to solve the above-described problems, the present invention provides a process cartridge that is detachably installed on a main body of an image forming apparatus, and the developing device according to any one of claims 1 to 4. A process cartridge is proposed in which the image carrier is integrated.

さらにまた、上記課題を解決するため、本発明は、請求項１ないし請求項４の何れかに記載の現像装置と前記像担持体とを備えたことを特徴とする画像形成装置を提案する。 Furthermore, in order to solve the above-described problems, the present invention proposes an image forming apparatus comprising the developing device according to any one of claims 1 to 4 and the image carrier.

本発明によれば、縦撹拌型の現像装置における撹拌搬送室に設ける補給トナーが補給されるトナー補給口が現像搬送室の現像剤が戻される受け渡し部より現像剤搬送方向下流にあっても第２搬送部材の回転方向を現像剤担持体と反対方向とし、受け渡し部における前記現像搬送室と前記撹拌搬送室との間の下壁に凸形状を設けることによって、補給トナーを現像ケースにおける現像剤担持体と反対側への片寄せ、第１搬送部材の回転方向を現像担持体と同一方向にすることにより、受け渡し現像剤を片寄せられている補給トナーの上方から混入することで混合撹拌を効果的に行うことができる。 According to the present invention, the toner replenishing port for replenishing the replenishment toner provided in the agitating and conveying chamber in the vertical agitating type developing device is provided even if the toner replenishing port in the developing and conveying chamber is downstream in the developer conveying direction from the delivery portion where the developer is returned. 2 The direction of rotation of the conveying member is opposite to that of the developer carrying member, and a convex shape is provided on the lower wall between the developing conveying chamber and the agitating conveying chamber in the transfer section, whereby the replenishing toner is supplied to the developing agent in the developing case. The mixing developer is mixed and stirred by mixing the replenishing toner from above the replenished toner by shifting the first developer to the opposite side of the carrier and rotating the first conveying member in the same direction as the developer carrier. Can be done effectively.

本発明の実施の形態１における画像形成装置を示す全体構成図である。1 is an overall configuration diagram illustrating an image forming apparatus according to Embodiment 1 of the present invention. 作像部を示す構成図である。It is a block diagram which shows an image creation part. 現像装置を示す断面図である。It is sectional drawing which shows a developing device. 現像装置内の現像剤の流れを示す説明図である。It is explanatory drawing which shows the flow of the developer in a developing device. 現像装置の受け渡し部を示す断面説明図である。FIG. 10 is an explanatory cross-sectional view illustrating a transfer unit of the developing device.

以下、本発明の実施の形態について、添付図面を参照して詳細に説明する。
図１は、電子写真方式の画像形成装置の一例を示す垂直断面図であり、ここに示した画像形成装置は、装置本体１内に配置されたドラム状の感光体より成る第１ないし第４の像担持体２Ｙ，２Ｍ，２Ｃ，２Ｋと、同じく装置本体１内に配置された無端状の中間転写ベルト３として構成された中間転写体を有している。中間転写ベルト３は支持ローラ４，５，６，７に巻き掛けられて矢印Ａ方向に回転駆動される。 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a vertical cross-sectional view showing an example of an electrophotographic image forming apparatus. The image forming apparatus shown here includes first to fourth drum-shaped photoconductors arranged in an apparatus main body 1. And image transfer bodies 2Y, 2M, 2C, and 2K, and an intermediate transfer body configured as an endless intermediate transfer belt 3 that is also disposed in the apparatus main body 1. The intermediate transfer belt 3 is wound around the support rollers 4, 5, 6 and 7 and rotated in the direction of arrow A.

上記中間転写ベルト３は、各像担持体２Ｙないし２Ｋの上方に位置し、該中間転写ベルト３の下側の走行辺が各像担持体２Ｙないし２Ｋの周面に当接していて、各像担持体の表面にそれぞれ形成された互いに異なる色のトナー像が重ねて転写され得る転写材の一例を構成するものである。 The intermediate transfer belt 3 is positioned above the image carriers 2Y to 2K, and the lower running side of the intermediate transfer belt 3 is in contact with the peripheral surface of the image carriers 2Y to 2K. It constitutes an example of a transfer material on which toner images of different colors respectively formed on the surface of the carrier can be transferred.

第１ないし第４の各像担持体２Ｙ，２Ｍ，２Ｃ，２Ｋ上にトナー像を形成し、そのトナー像を中間転写ベルト３に転写する構成は、そのトナー像の色が異なるだけで、実質的に全て同一であるため、第１の像担持体２Ｙにトナー像を形成し、そのトナー像を中間転写ベルト３に転写する構成だけを説明する。なお、Ｙ、Ｍ、Ｃ、Ｋの添え字はイエロー、マゼンタ、シアン、ブラックの色を示しており、これら添え字は必要に応じて割愛する。 The configuration in which a toner image is formed on each of the first to fourth image carriers 2Y, 2M, 2C, and 2K and the toner image is transferred to the intermediate transfer belt 3 is substantially different only in the color of the toner image. Since all of them are the same, only a configuration in which a toner image is formed on the first image carrier 2Y and the toner image is transferred to the intermediate transfer belt 3 will be described. The subscripts Y, M, C, and K indicate yellow, magenta, cyan, and black colors, and these subscripts are omitted as necessary.

図２は、添え字「Ｙ」を割愛して示しているが、イエローに対応した像担持体２と、その像担持体２の表面にトナー像を形成するための各作像装置を示す拡大図である。像担持体２は図２における時計方向に回転駆動され、このとき帯電電圧を印加された帯電ローラ８より成る帯電装置によって像担持体２が所定の極性に帯電される。帯電後の像担持体２には、図示していない光書き込み装置から出射する光変調されたレーザビームＬが照射され、これによって像担持体２上に静電潜像が形成される。この静電潜像は、後に詳述する現像装置２０によってイエロートナー像として可視像化される。 Although FIG. 2 omits the suffix “Y”, the image carrier 2 corresponding to yellow and each image forming device for forming a toner image on the surface of the image carrier 2 are enlarged. FIG. The image carrier 2 is rotationally driven in the clockwise direction in FIG. 2, and at this time, the image carrier 2 is charged to a predetermined polarity by a charging device including a charging roller 8 to which a charging voltage is applied. The charged image carrier 2 is irradiated with a light-modulated laser beam L emitted from an optical writing device (not shown), whereby an electrostatic latent image is formed on the image carrier 2. The electrostatic latent image is visualized as a yellow toner image by the developing device 20 described in detail later.

中間転写ベルト３を挟んで、像担持体２と反対側に一次転写ローラ９が配置され、この一次転写ローラ９に転写電圧が印加されることにより、像担持体２上のトナー像が、矢印Ａ方向に回転する中間転写ベルト３上に一次転写される。トナー像転写後の像担持体２上に付着する転写残トナーはクリーニング装置１０によって除去される。また、像担持体２上に残留する電荷は図示していない除電装置に除去され次の作像に備える。 A primary transfer roller 9 is disposed on the side opposite to the image carrier 2 with the intermediate transfer belt 3 interposed therebetween, and a transfer voltage is applied to the primary transfer roller 9 so that the toner image on the image carrier 2 is changed to an arrow. Primary transfer is performed on the intermediate transfer belt 3 rotating in the A direction. The transfer residual toner adhering to the image carrier 2 after the toner image transfer is removed by the cleaning device 10. Further, the electric charge remaining on the image carrier 2 is removed by a static eliminator (not shown) to prepare for the next image formation.

上述したところと全く同様にして、図１に示した第２ないし第４の像担持体２Ｍ，２Ｃ，２Ｋ上にシアントナー像、マゼンタトナー像及びブラックトナー像がそれぞれ形成され、これらのトナー像がイエロートナー像の転写された中間転写ベルト３上に順次重ねて一次転写され、中間転写ベルト３上に合成トナー像が形成される。トナー像転写後の各像担持体２Ｍ，２Ｃ，２Ｋ上の転写残トナーがクリーニング装置１０により除去されることも第１の像担持体２Ｙの場合と変わりはない。 In exactly the same manner as described above, a cyan toner image, a magenta toner image, and a black toner image are respectively formed on the second to fourth image carriers 2M, 2C, and 2K shown in FIG. Are sequentially superposed on the intermediate transfer belt 3 to which the yellow toner image has been transferred, and are primarily transferred to form a composite toner image on the intermediate transfer belt 3. The transfer residual toner on each of the image carriers 2M, 2C, 2K after the toner image transfer is removed by the cleaning device 10 is not different from the case of the first image carrier 2Y.

一方、図１に示すように、装置本体１内の下部には、例えば転写紙より成る記録媒体Ｐを収容した給紙カセット１１と、給紙ローラ１２を有する給紙装置１３が配置され、給紙ローラ１２の回転によって最上位の記録媒体Ｐが矢印Ｂ方向に送り出される。送り出された記録媒体は、レジストローラ対１３によって、所定のタイミングで支持ローラ６に巻き掛けられた中間転写ベルト３の部分と、これに対置された二次転写ローラ１４との間に給送される。このとき、２次転写ローラ１４には所定の転写電圧が印加され、これによって中間転写ベルト３上の合成トナー像が記録媒体Ｐに二次転写される。 On the other hand, as shown in FIG. 1, a paper feed cassette 11 containing a recording medium P made of, for example, transfer paper and a paper feed device 13 having a paper feed roller 12 are arranged at the lower part in the apparatus main body 1. As the paper roller 12 rotates, the uppermost recording medium P is sent in the direction of arrow B. The fed recording medium is fed by a registration roller pair 13 between a portion of the intermediate transfer belt 3 wound around the support roller 6 at a predetermined timing and a secondary transfer roller 14 disposed on the intermediate transfer belt 3. The At this time, a predetermined transfer voltage is applied to the secondary transfer roller 14, whereby the composite toner image on the intermediate transfer belt 3 is secondarily transferred to the recording medium P.

合成トナー像を二次転写された記録媒体Ｐはさらに上方に搬送されて定着装置１５を通り、このとき記録媒体Ｐ上のトナー像が熱と圧力の作用により定着される。定着装置１５を通過した記録媒体Ｐは、排紙ローラ対１６によって、装置本体１の上部の排紙部１７に排出される。また、トナー像転写後の中間転写ベルト３上に付着する転写残トナーはクリーニング装置１８によって除去される。なお、図２に示した作像装置はプロセスカートリッジとして構成され、機器に搭載することもできる。 The recording medium P on which the composite toner image has been secondarily transferred is further conveyed upward and passes through the fixing device 15. At this time, the toner image on the recording medium P is fixed by the action of heat and pressure. The recording medium P that has passed through the fixing device 15 is discharged by a paper discharge roller pair 16 to a paper discharge unit 17 at the top of the apparatus main body 1. Further, the transfer residual toner adhering to the intermediate transfer belt 3 after the toner image transfer is removed by the cleaning device 18. 2 is configured as a process cartridge, and can be mounted on a device.

現像装置２０は、図３に示すように、ポリエステル樹脂を主成分とするトナー（５．８μｍ）と磁性微粒子であるキャリア（３５μｍ）を７ｗｔ％に均一混合した現像剤が一定量充填された現像ケース２１と、この現像ケース２１に回転自在に支持され、かつ該現像ケース２１に形成された開口を通して像担持体２に近接して対向配置された現像剤担持体としての現像ローラ２２とを有し、該現像ローラ２２は図２の反時計方向に回転する現像スリーブ２３と、該スリーブ内に固定されＰ１極〜Ｐ５極の５つの磁極が形成された磁気ロール２４とを備えている。図３には５つの磁極Ｐ１極〜Ｐ５極の磁力がピークになる位置を示している。現像ローラ２２の下部側には、現像ケース２１に支持された現像剤規制部材としてのドクターブレード２５が近接配置され、該ドクターブレード２５によって現像ローラ２２上の現像剤量が規制される。現像装置２０には、現像ローラ２２に対向して、その斜め下方の現像搬送室２６と、ほぼ水平で現像搬送室２６より上方の撹拌搬送室２７とが設けられている。現像搬送室２６内には現像剤搬送部材としての第１搬送スクリュ２８が、撹拌搬送室２７内には現像剤搬送部材としての第２搬送スクリュ２９がそれぞれ配置されている。第１及び第２搬送スクリュ２８，２９は、その軸線が現像ローラ２２の軸線と平行で、かつ、第１搬送スクリュ２８は軸線方向において現像ローラ２２の全長に亘って隣接しており、第１搬送スクリュ２８の軸線方向の長さは現像ローラ２２の長さと同等かそれよりも多少長い長さに設定されている。同じく、軸線方向において現像ローラ２２の全長に亘って隣接する第２搬送スクリュ２９も第１搬送スクリュ２８と同じ長さでもよいが、本実施形態は第２搬送スクリュ２９の長さが第１搬送スクリュ２８の長く設定されている。そして、第１及び第２搬送スクリュ２８，２９は６００〜８００ｒｐｍで回転させることによって現像剤を撹拌しつつ搬送し、トナーとキャリアの均一混合と帯電付与を行っている。 As shown in FIG. 3, the developing device 20 is a developing device in which a fixed amount of a developer in which toner (5.8 μm) containing a polyester resin as a main component and a carrier (35 μm) as magnetic fine particles are uniformly mixed to 7 wt% is filled. A case 21 and a developing roller 22 as a developer carrying member that is rotatably supported by the developing case 21 and that is opposed to the image carrier 2 through an opening formed in the developing case 21 are provided. The developing roller 22 includes a developing sleeve 23 that rotates counterclockwise in FIG. 2 and a magnetic roll 24 that is fixed in the sleeve and has five magnetic poles P1 to P5. FIG. 3 shows the positions where the magnetic forces of the five magnetic poles P1 to P5 are peaked. A doctor blade 25 as a developer restricting member supported by the developing case 21 is disposed close to the lower side of the developing roller 22, and the amount of developer on the developing roller 22 is regulated by the doctor blade 25. The developing device 20 is provided with a developing and conveying chamber 26 obliquely below the developing roller 22 and a stirring and conveying chamber 27 that is substantially horizontal and above the developing and conveying chamber 26. A first transport screw 28 as a developer transport member is disposed in the development transport chamber 26, and a second transport screw 29 as a developer transport member is disposed in the agitation transport chamber 27. The first and second conveying screws 28 and 29 have their axes parallel to the axis of the developing roller 22, and the first conveying screw 28 is adjacent to the entire length of the developing roller 22 in the axial direction. The length of the conveying screw 28 in the axial direction is set to be equal to or slightly longer than the length of the developing roller 22. Similarly, the second conveying screw 29 adjacent to the entire length of the developing roller 22 in the axial direction may be the same length as the first conveying screw 28. However, in this embodiment, the length of the second conveying screw 29 is the first conveying screw. The screw 28 is set to be long. The first and second conveying screws 28 and 29 are rotated at 600 to 800 rpm to convey the developer while stirring, thereby uniformly mixing the toner and the carrier and applying the charge.

図４は、本発明に係る現像装置内での現像剤の流れを示す展開説明図である。
図４において、現像装置２０内にはトナー濃度センサ（図示せず）が設けられ、該センサがトナー濃度不足を検知すると、撹拌搬送室２７の現像剤搬送方向上流側（図の左端）に設けられたトナー補給部としてのトナー補給口３０から消費された量に応じた量のトナーが補給される。撹拌搬送室２７には、このトナー補給口３０に続いて現像搬送室２６と撹拌搬送室２７とが通ずる受け渡し部３１が設けられ、この受け渡し部３１において現像搬送室２６内でドクターブレード２５に掻き落とされた現像剤等が送り込まれる。そして、受け渡し部３１を過ぎた撹拌搬送室２７には現像ローラ２２に担持されて現像領域に達したが現像に供されなかった現像剤が現像ケース２１に形成された回収ガイド３２を介して戻され、この戻し現像剤は現像ローラ２２のほぼ全長に亘り、そしてこれらの現像剤が第２搬送スクリュ２９の回転によって図の右方へ搬送される。 FIG. 4 is a development explanatory view showing the flow of the developer in the developing device according to the present invention.
In FIG. 4, a toner concentration sensor (not shown) is provided in the developing device 20. When the sensor detects that the toner concentration is insufficient, it is provided on the upstream side (left end in the figure) of the agitating and conveying chamber 27 in the developer conveying direction. An amount of toner corresponding to the amount consumed from the toner supply port 30 serving as the toner supply unit is supplied. The agitating / conveying chamber 27 is provided with a transfer portion 31 through which the developer conveying chamber 26 and the agitating / conveying chamber 27 communicate with each other after the toner supply port 30, and the transfer blade 31 scrapes the doctor blade 25 within the developing and conveying chamber 26. Dropped developer or the like is sent. The developer that has been carried on the developing roller 22 and reached the developing area but has not been developed is returned to the agitating / conveying chamber 27 that has passed the transfer section 31 via a collection guide 32 formed in the developing case 21. Then, the return developer covers almost the entire length of the developing roller 22, and these developers are conveyed to the right in the drawing by the rotation of the second conveying screw 29.

第２搬送スクリュ２９によって撹拌されつつ搬送されることで、トナー濃度が均一となった撹拌搬送室２７の現像剤はその搬送方向下流側に設けられた送り込み部３３から現像搬送室２６に送り込まれる。この送り込み部３３では撹拌搬送室２７が現像搬送室２６より上方にあるので、現像剤送り込みは自重落下によって行われる。なお、受け渡し部３１及び送り込み部３３の位置は現像ローラ２２の左端と右端をそれぞれ越えた位置に設けられている。 By being transported while being stirred by the second transport screw 29, the developer in the stirring transport chamber 27 in which the toner density becomes uniform is fed into the developing transport chamber 26 from a feeding portion 33 provided on the downstream side in the transport direction. . Since the agitating / conveying chamber 27 is located above the developing / conveying chamber 26 in the feeding portion 33, the developer is fed by its own weight drop. Note that the positions of the transfer portion 31 and the feeding portion 33 are provided at positions beyond the left end and the right end of the developing roller 22, respectively.

このように現像装置２０は、第１搬送スクリュ２８にて撹拌搬送を行いつつ現像ローラ２２に現像剤供給を行い、第２搬送スクリュ２９によってすべて回収する方式を取っているため、図４に示すように、現像搬送室２６及び撹拌搬送室２７内の現像剤の堆積状態が斜めになる（供給スクリュ中の現像剤量が下流方向に従って減少する）。第１搬送スクリュ２８の径、ピッチと回転数から求まる現像剤搬送量能力をＷｍとし、現像ローラ２２上の現像剤搬送量をＷｓとすると、両者の関係がＷｍ＞Ｗｓとなる場合に現像剤が一様に現像ローラ２２上に搬送されるようになる。この条件が成立しないと第１搬送スクリュ２８の下流側において現像剤が不足してしまい現像ローラ２２への現像剤の供給が不可能となってしまう。 As described above, the developing device 20 employs a system in which the developer is supplied to the developing roller 22 while being agitated and conveyed by the first conveying screw 28 and is collected by the second conveying screw 29. As described above, the developer accumulation state in the developing and conveying chamber 26 and the agitating and conveying chamber 27 becomes oblique (the amount of developer in the supply screw decreases in the downstream direction). When the developer conveyance amount capability obtained from the diameter, pitch and rotation speed of the first conveyance screw 28 is Wm, and the developer conveyance amount on the developing roller 22 is Ws, the developer is obtained when the relationship between the two becomes Wm> Ws. Are uniformly conveyed onto the developing roller 22. If this condition is not satisfied, the developer is insufficient on the downstream side of the first conveying screw 28, and the developer cannot be supplied to the developing roller 22.

このようにして現像剤が搬送される現像装置において、撹拌搬送室２７内ではトナーが現像剤よりも比重が軽いので、補給トナーが現像剤上を移動してしまう上滑りという現象が発生することがあり、上滑りが発生すると地汚れやトナー飛散を招くおそれがある。さらに、新たに補給したトナーがある程度纏まったままで分散されないと、撹拌搬送室２７内での撹拌が不十分の現像剤が現像搬送室２６に送り込まれ、地汚れやトナー飛散の原因になることは先に説明した。 In the developing device in which the developer is transported in this manner, the toner has a specific gravity lighter than that of the developer in the agitating / conveying chamber 27, so that a phenomenon of upslip that causes the replenished toner to move on the developer may occur. In addition, if an upper slip occurs, there is a risk of causing soiling or toner scattering. Furthermore, if the newly replenished toner is not collected and dispersed to some extent, the developer with insufficient agitation in the agitating / conveying chamber 27 is fed into the developing / conveying chamber 26, which may cause background contamination and toner scattering. As explained earlier.

そこで、本発明では、新しく補給したトナーが上滑りせず、受け渡し部３１で現像搬送室２６から受け渡された現像剤に十分に分散されるよう次のように措置を講じている。
図５において、本発明の受け渡し部３１における現像剤の受け渡し方法は、現像搬送室２６が撹拌搬送室２７よりも重力方向下側にあるため、現像剤を上方へ移動させねばならず、一般に知られている現像搬送室２６の搬送方向下流側で溜まった現像剤の圧力で押し上げる方法であると、現像剤に余計なストレスが加わるだけでなく、受け渡された現像剤への補給トナーの分散性も不十分である。 Therefore, in the present invention, the following measures are taken so that the newly replenished toner does not slide up and is sufficiently dispersed in the developer delivered from the development transport chamber 26 by the delivery unit 31.
In FIG. 5, the developer delivery method in the delivery unit 31 of the present invention is generally known because the developer transport chamber 26 is located below the stirring transport chamber 27 in the gravity direction, and the developer must be moved upward. In this method, the developer is pushed up by the pressure of the developer accumulated on the downstream side in the transport direction of the developing transport chamber 26. In addition to adding extra stress to the developer, the supply toner is dispersed to the transferred developer. The nature is also insufficient.

そこで、本実施形態では受け渡し部３１を次のように構成する。
受け渡し部３１は、図５に示すように、その縦断面形状において上辺側が第１搬送スクリュ２８と第２搬送スクリュ２９の軸芯を結ぶ直線Ｓと平行な直線３５に形成され、下辺側は第１搬送スクリュ２８と第２搬送スクリュ２９のほぼ同心円状に湾曲し、そのほぼ中央には第１搬送スクリュ２８と第２搬送スクリュ２９との領域を区切るような先の尖った凸形状３６が形成されている。なお、本実施形態の凸形状３６の高さは上記結ぶ直線Ｓより若干下側を遮蔽し、結ぶ直線Ｓの上側を開放するような高さに設定されている。そして、この受け渡し部３１には現像搬送室２６の現像剤を撹拌搬送室２７へ送り出す部材として、図４及び図５に示すようなパドル３４が設けられ、該パドル３４は第１搬送スクリュ２８の軸に固定して設けられている。 Therefore, in this embodiment, the delivery unit 31 is configured as follows.
As shown in FIG. 5, the transfer portion 31 is formed in a straight line 35 parallel to the straight line S connecting the axial centers of the first conveying screw 28 and the second conveying screw 29 in the vertical cross-sectional shape, and the lower side is the first side. The first conveying screw 28 and the second conveying screw 29 are curved substantially concentrically, and a sharp convex shape 36 is formed in the center of the first conveying screw 28 and the second conveying screw 29 so as to divide the region between the first conveying screw 28 and the second conveying screw 29. Has been. It should be noted that the height of the convex shape 36 of the present embodiment is set such that the lower side of the connecting straight line S is shielded slightly and the upper side of the connecting straight line S is opened. The transfer section 31 is provided with a paddle 34 as shown in FIGS. 4 and 5 as a member for sending the developer in the developing transport chamber 26 to the agitating transport chamber 27. The paddle 34 is connected to the first transport screw 28. It is fixed to the shaft.

このように構成される受け渡し部３１は、第１搬送スクリュ２８の軸に固定されているパドル３４が現像ローラ２２と同方向である図５の反時計方向に回転され、第２搬送スクリュ２９は現像ローラ２２と反対方向の図５の時計方向に回転される。第２搬送スクリュ２９が現像ローラ２２の時計方向に回転されると、受け渡し部３１より搬送方向上流側で補給された新たなトナーは受け渡し部３１に到達したときに、全体的には図中左側に偏った状態になっており、第１搬送スクリュ２８と第２搬送スクリュ２９の間の下辺側に凸形状３６を設けていることで、第１搬送スクリュ２８側への落下を防止している。 In the transfer section 31 configured in this manner, the paddle 34 fixed to the shaft of the first conveying screw 28 is rotated counterclockwise in FIG. 5, which is the same direction as the developing roller 22, and the second conveying screw 29 is It is rotated in the clockwise direction in FIG. 5 opposite to the developing roller 22. When the second conveying screw 29 is rotated in the clockwise direction of the developing roller 22, when the new toner replenished on the upstream side in the conveying direction from the delivery unit 31 reaches the delivery unit 31, the entire left side in the figure. Since the convex shape 36 is provided on the lower side between the first conveyance screw 28 and the second conveyance screw 29, the falling toward the first conveyance screw 28 side is prevented. .

かくして、第２搬送スクリュ２９の回転方向を現像ローラ２２と反対方向とすることと上記凸形状３６を設けることによって、補給トナーを現像ケース２１における現像ローラ２２と反対側への片寄せを効果的に行い、第１搬送スクリュ２８の回転方向を現像ローラ２２と同一方向にすることにより、受け渡し現像剤を片寄せられている補給トナーの上方から混入することで混合撹拌を効果的に行うことができる。
このとき、現像搬送室２６の現像剤は受け渡し部３１に設けたパドル３４によって平行直線３５に沿ってスムーズに移動し、そしてトナー補給口３０から補給された新トナーに対する上側からの現像剤混合が行われるので、トナーの分散が確実に促進される。なお、パドル３４は第１搬送スクリュ２８の軸に２枚以上配置と、補給トナーに受け渡し現像剤を適度に分けて混入されるので、よりトナーを分散撹拌された状態になる。 Thus, the rotation direction of the second conveying screw 29 is opposite to that of the developing roller 22 and the convex shape 36 is provided, so that the replenishment toner is effectively shifted to the opposite side of the developing roller 22 in the developing case 21. In this manner, the first conveying screw 28 is rotated in the same direction as that of the developing roller 22, so that the mixed developer can be effectively mixed by mixing the transferred developer from above the replenished toner that has been offset. it can.
At this time, the developer in the developing transport chamber 26 moves smoothly along the parallel straight line 35 by the paddle 34 provided in the transfer section 31, and the developer mixing from above with the new toner replenished from the toner replenishing port 30 is performed. As a result, toner dispersion is surely promoted. Two or more paddles 34 are disposed on the shaft of the first conveying screw 28, and the developer is transferred to the replenishing toner in an appropriate manner so that the toner is further dispersed and stirred.

なお、現像装置２０に設けるトナー濃度測定用のセンサ（図示せず）は、受け渡し部部３１で図５の第１搬送スクリュ２８右下に配置すると、補給トナーが第１搬送スクリュ２８への落下による濃度検知の誤差発生が防止でき、現像装置２０内のトナー濃度検知が正確かつ安定化する。 Note that a toner concentration measurement sensor (not shown) provided in the developing device 20 is disposed at the right lower portion of the first conveying screw 28 in FIG. Therefore, it is possible to prevent an error in density detection due to toner, and to accurately and stably detect the toner density in the developing device 20.

１画像形成装置本体（装置本体）、
２像担持体
２０現像装置
２２現像ローラ（現像剤担持体）、
２５ドクターブレード（現像剤規制部材）
２６現像搬送室
２７撹拌搬送室
２８第１搬送スクリュ（第１搬送部材）
２９第２搬送スクリュ（第２搬送部材）
３１受け渡し部、
３３送り込み部
３４パドル
３６凸形状 1 image forming apparatus body (apparatus body),
2 image carrier 20 developing device 22 developing roller (developer carrier),
25 Doctor blade (developer regulating member)
26 Developing transport chamber 27 Stirring transport chamber 28 First transport screw (first transport member)
29 Second conveying screw (second conveying member)
31 delivery section,
33 Feeding part 34 Paddle 36 Convex shape

特開平１１−１７４８１０号公報Japanese Patent Laid-Open No. 11-174810 特開２００８−２６４０８号公報JP 2008-26408 A

Claims

静電潜像を担持する像担持体と対向配置され、磁界発生手段を内包する現像剤担持体と、
該現像剤担持体の下方に位置し、供給するトナー及びキャリアを有する現像剤を当該現像剤担持体の回転軸線方向に沿って搬送する第１搬送部材を備えた現像搬送室と、
前記現像剤担持体の下方に対向するように配設され、前記現像剤担持体に担持された現像剤の量を規制する現像剤規制部材と、
前記像担持体と対向位置を過ぎた位置で、前記現像剤担持体上から離脱した現像剤を回収し、前記現像剤担持体の回転軸線方向に沿って撹拌しつつ前記第１搬送部材と逆方向に搬送する第２搬送部材を備えた撹拌搬送室とを有し、
前記現像搬送室と前記撹拌搬送室とが隔壁で仕切られているとともに、前記撹拌搬送室が前記現像搬送室より上方に配置されており、
前記撹拌搬送室の現像剤搬送方向下流側に前記現像搬送室へ現像剤を送り込む送り込み部が設けられ、前記現像搬送室の送り込み部よりも現像剤搬送方向上流側に前記撹拌搬送室へ現像剤を受け渡す受け渡し部が設けられている現像装置において、
前記第１搬送部材の回転方向が前記現像剤担持体の回転方向と同一方向で、前記第２搬送部材の回転方向が前記現像剤担持体の回転方向と反対方向に設定されているとともに、
前記撹拌搬送室には前記受け渡し部よりも現像剤搬送方向上流側にトナー補給部が設けられ、
前記第１搬送部材の前記受け渡し部に対向する位置には、現像剤を上方へ送り出す部材が設けられているとともに、
前記受け渡し部における前記現像搬送室と前記撹拌搬送室との間の下壁に凸形状が形成されていることを特徴とする現像装置。 A developer carrying body disposed opposite to an image carrying body carrying an electrostatic latent image and containing magnetic field generating means;
A developer transport chamber provided with a first transport member that is positioned below the developer carrier and transports a developer having toner and a carrier to be supplied along the direction of the rotation axis of the developer carrier;
A developer regulating member disposed to face the lower side of the developer carrying member and regulating the amount of developer carried on the developer carrying member;
At a position past the image carrier, the developer separated from the developer carrier is collected, and the developer is agitated along the rotation axis direction of the developer carrier and is opposite to the first conveying member. A stirring and conveying chamber provided with a second conveying member that conveys in the direction;
The developing and conveying chamber and the agitating and conveying chamber are partitioned by a partition, and the agitating and conveying chamber is disposed above the developing and conveying chamber,
A feeding portion for feeding the developer into the developing conveyance chamber is provided on the downstream side in the developer conveyance direction of the stirring conveyance chamber, and the developer is supplied to the stirring conveyance chamber on the upstream side in the developer conveyance direction from the feeding portion of the development conveyance chamber. In a developing device provided with a delivery section that delivers
The rotation direction of the first transport member is set in the same direction as the rotation direction of the developer carrier, and the rotation direction of the second transport member is set in a direction opposite to the rotation direction of the developer carrier.
In the agitating and conveying chamber, a toner replenishing portion is provided upstream of the delivery portion in the developer conveying direction,
At a position facing the delivery portion of the first conveying member, a member for sending the developer upward is provided,
A developing device, wherein a convex shape is formed on a lower wall between the developing conveyance chamber and the agitation conveyance chamber in the transfer section.

請求項１に記載の現像装置において、前記上方へ送り出す部材がパドルであり、該パドルが前記第１搬送部材の回転軸に等角度ごとに複数枚設けられていることを特徴とする現像装置。 2. The developing device according to claim 1, wherein the member to be sent upward is a paddle, and a plurality of the paddles are provided at equal angles on a rotation shaft of the first conveying member.

請求項１または２に記載の現像装置において、前記凸形状は前記第１搬送部材と前記第２搬送部材の回転軸線を結ぶ直線よりも下側で、前記現像搬送室と前記撹拌搬送室を遮ることを特徴とする現像装置。 3. The developing device according to claim 1, wherein the convex shape is below a straight line connecting a rotation axis of the first transport member and the second transport member, and blocks the development transport chamber and the agitation transport chamber. A developing device.

請求項１ないし３の何れか１つに記載の現像装置において、前記受け渡し部における、前記現像搬送室と前記撹拌搬送室の境界部の上壁が前記第１搬送部材及び前記第２搬送部材の回転軸線を結ぶ直線とはほぼ平行な直線であることを特徴とする現像装置。 4. The developing device according to claim 1, wherein an upper wall of a boundary between the developing conveyance chamber and the agitation conveyance chamber in the transfer portion is formed between the first conveyance member and the second conveyance member. A developing device characterized in that the developing device is a straight line substantially parallel to a straight line connecting the rotation axes.

画像形成装置の装置本体に対して着脱自在に設置されるプロセスカートリッジであって、
請求項１ないし請求項４の何れか１つに記載の現像装置と前記像担持体とが一体化されたことを特徴とするプロセスカートリッジ。 A process cartridge that is detachably installed on the main body of the image forming apparatus,
5. A process cartridge, wherein the developing device according to claim 1 and the image carrier are integrated.

請求項１ないし請求項４の何れか１つに記載の現像装置と前記像担持体とを備えたことを特徴とする画像形成装置。 An image forming apparatus comprising the developing device according to claim 1 and the image carrier.