JP2012027243A - Developing device and image forming device equipped therewith - Google Patents

Developing device and image forming device equipped therewith Download PDF

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JP2012027243A
JP2012027243A JP2010165904A JP2010165904A JP2012027243A JP 2012027243 A JP2012027243 A JP 2012027243A JP 2010165904 A JP2010165904 A JP 2010165904A JP 2010165904 A JP2010165904 A JP 2010165904A JP 2012027243 A JP2012027243 A JP 2012027243A
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developer
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supply port
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JP5323012B2 (en
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Hikaru Tomitaku
光 富宅
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Kyocera Document Solutions Inc
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Kyocera Mita Corp
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Abstract

PROBLEM TO BE SOLVED: To provide a developing device in which a developer just supplied from a developer supply port is discharged from a developer discharge port and an imaging forming device equipped therewith.SOLUTION: A developing device 14 comprises a stirring member 23 which is rotatably pivoted to a developing container 22 and stirs and conveys a developer, a developer supplying port 22g for supplying a developer in the developing container 22, a magnetic roller 52 which is disposed facing the developer supplying port 22g from the outside of the developing container 22 and conveys a developer from the developer supplying port 22g into the developing container 22 and a developer discharging port 22h in which an excessive developer in the developing container 22 is discharged. The developer discharging port 22h is formed in a longitudinal direction of the developing container 22. The developer supplying port 22g is formed in the vicinity of the lower side of the developer discharging port 22h. A stirring member 23 rotates toward the side of the developer supplying port 22g from the side of the developer discharging port 22h. The magnetic roller 52 rotates in the same direction of the stirring member 23.

Description

本発明は、電子写真方式を利用した複写機、プリンタ、ファクシミリ、それらの複合機等の画像形成装置に用いる現像装置及びそれを備えた画像形成装置に関し、特に、トナーとキャリアとからなる2成分現像剤の補給を行うとともに余剰現像剤を排出する現像装置及びそれを備えた画像形成装置に関するものである。   BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, or a composite machine using an electrophotographic system, and an image forming apparatus including the developing device. The present invention relates to a developing device that replenishes developer and discharges excess developer, and an image forming apparatus including the developing device.

画像形成装置においては、感光体等からなる像担持体上に形成した潜像を、現像装置により現像しトナー像として可視化することを行っている。このような現像装置の一つとして、2成分現像剤を用いる2成分現像方式が採用されている。この種の現像装置は現像容器内に磁性キャリアとトナーとからなる現像剤を収容し、像担持体に現像剤を供給する現像ローラが配設されるとともに、現像容器内の現像剤を搬送撹拌しながら現像ローラへと供給する撹拌部材が配設されている。   In an image forming apparatus, a latent image formed on an image carrier made of a photoreceptor or the like is developed by a developing device and visualized as a toner image. As one of such developing devices, a two-component developing system using a two-component developer is employed. This type of developing device contains a developer composed of a magnetic carrier and toner in a developing container, and a developing roller for supplying the developer to the image carrier is disposed, and the developer in the developing container is conveyed and stirred. A stirring member for supplying the developing roller is provided.

この現像装置では、現像動作によってトナーは消費されていく一方キャリアは消費されずに現像装置内に残る。従って、現像容器内でトナーとともに撹拌されるキャリアは撹拌頻度が多くなるにつれて劣化し、その結果トナーに対するキャリアの帯電付与性能が徐々に低下してしまう。   In this developing device, the toner is consumed by the developing operation, while the carrier is not consumed and remains in the developing device. Accordingly, the carrier stirred together with the toner in the developing container deteriorates as the stirring frequency increases, and as a result, the charge imparting performance of the carrier to the toner gradually decreases.

そこで、現像容器内にキャリアを含む現像剤を補給するとともに、余剰となった現像剤を排出することで、帯電性能の低下を抑制するようにした現像装置が提案されている。   In view of this, there has been proposed a developing device in which a developer containing a carrier is replenished in a developing container and a surplus developer is discharged to suppress a decrease in charging performance.

例えば、特許文献1では、現像剤補給口が現像容器の上壁に設けられ、現像剤排出口が現像剤補給口に対して現像剤搬送方向の下流側に設けられ、更に撹拌部材はスクリューにて現像剤を撹拌、搬送する。撹拌部材のスクリューのピッチ幅が現像剤排出口近傍で狭くなっており、これによって現像剤が現像剤排出口近傍で滞留するようになっている。現像容器内の現像剤量が増加した場合に、現像剤排出口近傍で現像剤の嵩が高くなり、余剰の現像剤が現像剤排出部から現像容器外に溢れ出ることになる。   For example, in Patent Document 1, the developer supply port is provided on the upper wall of the developer container, the developer discharge port is provided on the downstream side in the developer transport direction with respect to the developer supply port, and the stirring member is provided on the screw. Stir and transport the developer. The pitch width of the screw of the stirring member is narrow in the vicinity of the developer discharge port, so that the developer stays in the vicinity of the developer discharge port. When the amount of developer in the developer container increases, the volume of the developer increases near the developer discharge port, and excess developer overflows from the developer discharge portion to the outside of the developer container.

また、特許文献2では、現像容器内に二つの撹拌部材が設けられ、撹拌部材が回転することにより、現像剤が現像容器内を循環する。現像剤補給口が一方の撹拌部材の端部に隣接して設けられ、現像剤排出口が他方の撹拌部材の端部に隣接して設けられる。現像剤補給口から現像剤が補給され、現像容器内を循環した現像剤が現像剤排出部から排出される。   In Patent Document 2, two agitating members are provided in the developing container, and the developer circulates in the developing container by rotating the agitating member. A developer supply port is provided adjacent to the end of one stirring member, and a developer discharge port is provided adjacent to the end of the other stirring member. Developer is supplied from the developer supply port, and the developer circulated in the developer container is discharged from the developer discharge portion.

特開2001−142301号公報(段落[0031]〜[0033]、第3図)JP 2001-142301 (paragraphs [0031] to [0033], FIG. 3) 特開平9−274385号公報(段落[0014]〜[0016]、第1図)Japanese Patent Laid-Open No. 9-274385 (paragraphs [0014] to [0016], FIG. 1)

しかしながら、上述した特許文献1、2では、現像剤を現像剤排出口から排出するときに、現像剤補給口から供給されたばかりの帯電性能が良好な現像剤も含んで現像剤排出口から排出されるという不都合があった。   However, in Patent Documents 1 and 2 described above, when the developer is discharged from the developer discharge port, it is discharged from the developer discharge port including the developer having a good charging performance just supplied from the developer supply port. There was an inconvenience.

本発明は、上記のような課題を解決するためになされたものであり、現像剤補給口から供給されたばかりの現像剤が現像剤排出口から排出されることを抑えた現像装置及びそれを備えた画像形成装置を提供することを目的とする。   The present invention has been made to solve the above-described problems, and includes a developing device that suppresses the developer just supplied from the developer supply port from being discharged from the developer discharge port, and the same. Another object of the present invention is to provide an image forming apparatus.

上記目的を達成するために第1の発明の現像装置は、現像剤を収容する現像容器と、前記現像容器に回転可能に軸支され前記現像容器内の現像剤を撹拌、搬送する撹拌部材と、前記現像容器内に現像剤を供給する現像剤補給口と、前記現像容器の外側から前記現像剤補給口に対向して配置され前記現像剤補給口から前記現像容器内に現像剤を搬送する補給搬送部材と、前記現像容器内の余剰の現像剤が排出される現像剤排出口とを備え、前記現像剤排出口は前記現像容器の長手方向の側壁に形成され、前記現像剤補給口は前記現像剤排出口の下側近傍に形成され、前記撹拌部材は前記現像剤排出口側から前記現像剤補給口側に向けて回転し、前記補給搬送部材は前記撹拌部材と同じ方向に回転することを特徴としている。   In order to achieve the above object, a developing device according to a first aspect of the present invention includes: a developing container that contains a developer; and a stirring member that is rotatably supported by the developing container and that stirs and conveys the developer in the developing container. A developer replenishing port for supplying the developer into the developing container, and a developer replenishing port that is disposed to face the developer replenishing port from the outside of the developing container and conveys the developer into the developing container from the developer replenishing port. A replenishment conveyance member; and a developer discharge port through which excess developer in the developer container is discharged. The developer discharge port is formed in a side wall in a longitudinal direction of the developer container, and the developer supply port is Formed near the lower side of the developer discharge port, the stirring member rotates from the developer discharge port side toward the developer supply port side, and the supply transport member rotates in the same direction as the stirring member. It is characterized by that.

また、第2の発明では、上記の現像装置において、前記補給搬送部材は表面に磁界を発生させる磁気ローラからなることを特徴としている。   According to a second aspect of the present invention, in the above developing device, the replenishment transport member is a magnetic roller that generates a magnetic field on the surface.

また、第3の発明では、上記の現像装置において、前記現像剤補給口の上端縁と前記磁気ローラとの隙間は前記磁気ローラ上に形成される磁気ブラシの高さと略等しく、前記現像剤補給口の下端縁と前記磁気ローラとの隙間は前記磁気ブラシの高さよりも大きいことを特徴としている。   According to a third aspect of the present invention, in the above developing device, the gap between the upper edge of the developer supply port and the magnetic roller is substantially equal to the height of the magnetic brush formed on the magnetic roller, and the developer supply A gap between the lower edge of the mouth and the magnetic roller is larger than the height of the magnetic brush.

また、第4の発明では、上記の現像装置において、前記現像剤補給口は、前記現像剤排出口に対して前記撹拌部材の現像剤搬送方向の下流側に配置されることを特徴としている。   According to a fourth aspect of the present invention, in the above developing device, the developer replenishing port is disposed downstream of the stirring member in the developer transport direction with respect to the developer discharge port.

また、第5の発明では、上記の現像装置において、前記現像剤補給口は、前記現像剤排出口に対して前記撹拌部材の現像剤搬送方向で同じ位置に配置されることを特徴としている。   According to a fifth aspect of the present invention, in the above developing device, the developer replenishing port is disposed at the same position in the developer transport direction of the stirring member with respect to the developer discharge port.

また、第6の発明では、上記の構成の現像装置が搭載された画像形成装置である。   According to a sixth aspect of the invention, there is provided an image forming apparatus equipped with the developing device having the above configuration.

第1の発明によれば、現像剤が現像剤補給口から現像容器内に供給されるときに、撹拌部材が現像剤排出口側から現像剤補給口側に向けて回転するために、供給された現像剤は現像容器内で現像剤補給口側から撹拌部材に対して現像剤補給口の反対側に搬送され、更に、撹拌部材の回転にともない現像容器の長手方向に搬送される。このように現像剤補給口から供給された現像剤は現像剤排出口に直ちに搬送されることはない。また、現像容器内の現像剤補給口の上側近傍では、撹拌部材と補給搬送部材とが対向面において互いに逆方向に移動し、つまり補給搬送部材が現像剤補給口側から現像剤排出口側に向かって回転することによって、現像容器内の現像剤補給口の上側近傍では現像剤が上側に持ち上がり、現像剤補給口の上側に配置される現像剤排出口の現像剤の嵩が高くなる。この嵩が高くなった現像剤は、撹拌部材によって搬送方向の上流側から搬送されるものであり、現像剤排出口から余剰現像剤として排出される。従って、現像剤補給口から供給されたばかりの現像剤が現像剤排出口から排出されることを抑えることができる。   According to the first invention, when the developer is supplied from the developer supply port into the developer container, the stirring member is supplied to rotate from the developer discharge port side toward the developer supply port side. The developer is conveyed from the developer replenishing port side to the side opposite to the developer replenishing port in the developing container, and further conveyed in the longitudinal direction of the developing container as the agitating member rotates. As described above, the developer supplied from the developer supply port is not immediately conveyed to the developer discharge port. Further, in the vicinity of the upper side of the developer supply port in the developer container, the agitating member and the supply transport member move in opposite directions on the opposing surface, that is, the supply transport member moves from the developer supply port side to the developer discharge port side. By rotating toward the upper side, the developer is lifted upward in the vicinity of the upper side of the developer supply port in the developer container, and the volume of the developer at the developer discharge port disposed above the developer supply port is increased. The developer having increased bulk is transported from the upstream side in the transport direction by the stirring member, and is discharged as an excess developer from the developer discharge port. Therefore, it is possible to suppress the developer just supplied from the developer supply port from being discharged from the developer discharge port.

また、第2の発明によれば、補給搬送部材が磁気ローラからなるので、補給搬送部材の表面に磁気ブラシが形成され、この磁気ブラシにて現像剤補給口から現像容器に供給された現像剤が現像剤補給口内に戻ることを防止している。   According to the second invention, since the replenishing and conveying member is made of a magnetic roller, a magnetic brush is formed on the surface of the replenishing and conveying member, and the developer supplied from the developer replenishing port to the developing container by this magnetic brush. Is prevented from returning into the developer supply port.

また、第3に記載の発明によれば、現像剤補給口の上端縁と磁気ローラとの隙間が磁気ブラシの高さと略等しいので、現像容器に供給された現像剤が現像剤補給口内に戻ることを確実に防止するとともに、現像剤補給口の下端縁と磁気ローラとの隙間が磁気ブラシの高さよりも大きいので、現像剤補給口から現像容器内に現像剤を十分に供給することができる。   According to the third aspect of the invention, since the gap between the upper end edge of the developer supply port and the magnetic roller is substantially equal to the height of the magnetic brush, the developer supplied to the developer container returns into the developer supply port. The gap between the lower edge of the developer replenishing port and the magnetic roller is larger than the height of the magnetic brush, so that the developer can be sufficiently supplied from the developer replenishing port into the developing container. .

また、第4に記載の発明によれば、現像剤補給口が現像剤排出口に対して撹拌部材の現像剤搬送方向の下流側に配置されるので、現像剤補給口から現像容器内に供給された現像剤は、現像剤排出口に直ちに搬送されることがなく、撹拌部材の回転にともない現像容器の長手方向に確実に搬送される。   According to the fourth aspect of the present invention, the developer supply port is disposed downstream of the developer discharge port in the developer transport direction with respect to the developer discharge port, so that the developer supply port supplies the developer into the developer container. The developed developer is not immediately conveyed to the developer discharge port, but is reliably conveyed in the longitudinal direction of the developing container as the stirring member rotates.

また、第5に記載の発明によれば、現像剤補給口が現像剤排出口に対して撹拌部材の現像剤搬送方向で同じ位置に配置されるので、現像剤補給口の上側に配置される現像剤排出口の現像剤の嵩が十分に高くなり、余剰現像剤を現像剤排出口から確実に排出させることができる。   According to the fifth aspect of the invention, since the developer supply port is disposed at the same position in the developer transport direction of the stirring member with respect to the developer discharge port, the developer supply port is disposed above the developer supply port. The bulk of the developer at the developer discharge port becomes sufficiently high, and the excess developer can be reliably discharged from the developer discharge port.

また、第6に記載の発明によれば、現像剤補給口から供給されたばかりの現像剤が現像剤排出口から排出されることを抑えた現像装置を備え、現像剤の帯電性能の低下による画像不良を効果的に防止可能な画像形成装置にすることができる。   According to the sixth aspect of the present invention, the image forming apparatus is provided with a developing device that suppresses the developer just supplied from the developer replenishing port from being discharged from the developer discharging port, and is caused by a decrease in the charging performance of the developer. An image forming apparatus capable of effectively preventing defects can be obtained.

本発明の第1実施形態に係る現像装置を搭載した画像形成装置の概略構成を示す図1 is a diagram showing a schematic configuration of an image forming apparatus equipped with a developing device according to a first embodiment of the present invention. 第1実施形態に係る現像装置の概略構成を示す側面断面図Side surface sectional drawing which shows schematic structure of the developing device which concerns on 1st Embodiment. 第1実施形態に係る現像装置における撹拌部の断面を示す上平面図An upper plan view showing a cross section of a stirring unit in the developing device according to the first embodiment. 第1実施形態に係る撹拌部における現像剤補給口と現像剤排出口との配置を模式的に示す平面図The top view which shows typically arrangement | positioning of the developer supply port and developer discharge port in the stirring part which concerns on 1st Embodiment. 第1実施形態に係る撹拌部の現像剤補給口から現像剤を供給している状態を示す断面側面図Sectional side view which shows the state which has supplied the developer from the developer supply port of the stirring part which concerns on 1st Embodiment. 第1実施形態に係る撹拌部の現像剤補給口を示す断面側面図Sectional side view which shows the developer supply port of the stirring part which concerns on 1st Embodiment 比較例に係る現像装置おける撹拌部を模式的に示す平面図The top view which shows typically the stirring part in the image development apparatus concerning a comparative example 第1実施形態と比較例との排出現像剤の帯電量を示す図The figure which shows the charge amount of the discharge developer of 1st Embodiment and a comparative example. 第2実施形態に係る現像装置における撹拌部を模式的に示す平面図The top view which shows typically the stirring part in the developing device which concerns on 2nd Embodiment.

以下に本発明の実施形態について図面を参照して説明するが、本発明は、この実施形態に限定されない。また発明の用途やここで示す用語等はこれに限定されるものではない。   Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Further, the use of the invention and the terms shown here are not limited thereto.

(第1実施形態)
図1は、本発明の実施形態に係る現像装置を搭載した画像形成装置の概略構成を示す図である。画像形成装置1は、その下部に配設された給紙部2と、この給紙部2の側方に配設された用紙搬送部3と、この用紙搬送部3の上方に配設された画像形成部4と、この画像形成部4よりも排出側に配設された定着部5と、画像形成部4及び定着部5の上方に配設された画像読取部6と、ホッパー110とを備えている。
(First embodiment)
FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus equipped with a developing device according to an embodiment of the present invention. The image forming apparatus 1 is provided with a sheet feeding unit 2 disposed in a lower portion thereof, a sheet conveying unit 3 disposed on a side of the sheet feeding unit 2, and an upper side of the sheet conveying unit 3. An image forming unit 4, a fixing unit 5 disposed on the discharge side of the image forming unit 4, an image reading unit 6 disposed above the image forming unit 4 and the fixing unit 5, and a hopper 110. I have.

給紙部2は、用紙9を収容する複数の給紙カセット7を備えており、給紙ローラ8の回転により、複数の給紙カセット7のうち選択された給紙カセット7から用紙9を1枚ずつ用紙搬送部3に送り出す。   The paper feed unit 2 includes a plurality of paper feed cassettes 7 for containing paper 9, and the paper 9 from the paper feed cassette 7 selected from among the plurality of paper feed cassettes 7 by rotating the paper feed roller 8. Each sheet is sent out to the sheet transport unit 3.

用紙搬送部3に送られた用紙9は、用紙搬送経路10を経由して画像形成部4に向けて搬送される。画像形成部4は、電子写真プロセスによって、用紙9にトナー像を形成するものであり、図1の矢印方向に回転可能に支持された感光体11と、この感光体11の周囲にその回転方向に沿って、帯電部12、露光部13、現像装置14、転写部15、クリーニング部16、及び除電部17を備えている。   The paper 9 sent to the paper transport unit 3 is transported toward the image forming unit 4 via the paper transport path 10. The image forming unit 4 forms a toner image on a sheet 9 by an electrophotographic process. The image forming unit 4 is a photoconductor 11 supported so as to be rotatable in the direction of an arrow in FIG. A charging unit 12, an exposure unit 13, a developing device 14, a transfer unit 15, a cleaning unit 16, and a charge eliminating unit 17 are provided.

帯電部12は、高電圧を印加される帯電ワイヤを備えており、この帯電ワイヤからのコロナ放電によって感光体11表面に所定電位を与えると、感光体11表面が一様に帯電させられる。そして、画像読取部6によって読み取られた原稿の画像データに基づく光が、露光部13により感光体11に照射されると、感光体11の表面電位が選択的に減衰され、感光体11表面に静電潜像が形成される。   The charging unit 12 includes a charging wire to which a high voltage is applied. When a predetermined potential is applied to the surface of the photoconductor 11 by corona discharge from the charging wire, the surface of the photoconductor 11 is uniformly charged. Then, when light based on the image data of the original read by the image reading unit 6 is irradiated to the photoconductor 11 by the exposure unit 13, the surface potential of the photoconductor 11 is selectively attenuated, and the surface of the photoconductor 11 is irradiated. An electrostatic latent image is formed.

次いで、現像装置14が感光体11表面の静電潜像を現像し、感光体11表面にトナー像が形成される。このトナー像が転写部15によって感光体11と転写部15との間に供給された用紙9に転写される。   Next, the developing device 14 develops the electrostatic latent image on the surface of the photoconductor 11, and a toner image is formed on the surface of the photoconductor 11. This toner image is transferred by the transfer unit 15 to the paper 9 supplied between the photoconductor 11 and the transfer unit 15.

トナー像が転写された用紙9は、画像形成部4の用紙搬送方向の下流側に配置された定着部5に向けて搬送される。定着部5では、加熱部材18及び加圧ローラ19によって、用紙9が加熱加圧され、用紙9上にトナー像が溶融定着される。次いで、トナー像が定着された用紙9は、排出ローラ対20によって排出トレイ21上に排出される。   The sheet 9 on which the toner image has been transferred is conveyed toward the fixing unit 5 disposed on the downstream side of the image forming unit 4 in the sheet conveying direction. In the fixing unit 5, the sheet 9 is heated and pressed by the heating member 18 and the pressure roller 19, and the toner image is melted and fixed on the sheet 9. Next, the sheet 9 on which the toner image is fixed is discharged onto the discharge tray 21 by the discharge roller pair 20.

転写部15による転写後、感光体11表面に残留しているトナーは、クリーニング部16により除去され、また感光体11表面の残留電荷は除電部17により除去される。そして、感光体11は帯電部12によって再び帯電され、以下同様にして画像形成が行われる。そして、現像装置14の現像剤が所定量以下になると、ホッパー110から現像装置14に現像剤が供給される。   After the transfer by the transfer unit 15, the toner remaining on the surface of the photoconductor 11 is removed by the cleaning unit 16, and the residual charge on the surface of the photoconductor 11 is removed by the charge eliminating unit 17. Then, the photosensitive member 11 is charged again by the charging unit 12, and image formation is performed in the same manner. When the developer in the developing device 14 becomes a predetermined amount or less, the developer is supplied from the hopper 110 to the developing device 14.

次に、現像装置について図2に基づいて説明する。図2は画像形成装置1に用いられる現像装置の概略構成の断面を示す側面図である。   Next, the developing device will be described with reference to FIG. FIG. 2 is a side view showing a cross section of a schematic configuration of a developing device used in the image forming apparatus 1.

現像装置14は、トナーと磁性キャリアからなる2成分現像剤を収容する現像容器22と、この現像剤を撹拌する第1及び第2撹拌部材23、24と、現像ローラ27、及び規制部材28とを備えている。   The developing device 14 includes a developing container 22 that stores a two-component developer composed of toner and a magnetic carrier, first and second stirring members 23 and 24 that stir the developer, a developing roller 27, and a regulating member 28. It has.

現像容器22は、現像装置14の外郭を構成し、その下部で仕切り部22bによって第1搬送路22cと第2搬送路22dに仕切っている。第1搬送路22c及び第2搬送路22dには、磁性キャリアとトナーからなる現像剤が収容される。また、現像容器22は、第1及び第2撹拌部材23、24と現像ローラ27を回転可能に保持している。更に、現像容器22には、現像ローラ27を感光体11に向けて露出させる開口が形成されている。   The developing container 22 constitutes an outline of the developing device 14, and is partitioned into a first transport path 22c and a second transport path 22d by a partitioning portion 22b at a lower portion thereof. The first transport path 22c and the second transport path 22d contain a developer composed of a magnetic carrier and toner. Further, the developing container 22 holds the first and second stirring members 23 and 24 and the developing roller 27 rotatably. Further, the developing container 22 has an opening that exposes the developing roller 27 toward the photoconductor 11.

第2撹拌部材24が現像ローラ27の右下方で、第2搬送路22d内に設けられ、第1撹拌部材23が第2撹拌部材24の右方に隣接して、第1搬送路22c内に設けられる。   The second stirring member 24 is provided in the second conveyance path 22d at the lower right of the developing roller 27, and the first stirring member 23 is adjacent to the right side of the second stirring member 24 and in the first conveyance path 22c. Provided.

第1及び第2撹拌部材23、24は現像剤を撹拌して現像剤中のトナーを所定のレベルに帯電させる。これによりトナーは磁性キャリアに保持される。また、第1搬送路22cと第2搬送路22dを仕切る仕切り部22bの長手方向(図2の紙面の表裏方向)の両端部分には、連通部(図略)が設けられており、第1撹拌部材23が回転すると、帯電した現像剤が仕切り部22bに設けた一方の連通部から第2搬送路22dに搬送され、現像剤が第1搬送路22c内と第2搬送路22d内とを循環する。そして、第2撹拌部材24から現像ローラ27に現像剤が供給される。   The first and second stirring members 23 and 24 stir the developer to charge the toner in the developer to a predetermined level. Thus, the toner is held on the magnetic carrier. Further, communication portions (not shown) are provided at both end portions in the longitudinal direction (front and back direction of the paper surface of FIG. 2) of the partition portion 22b that partitions the first transport path 22c and the second transport path 22d. When the agitating member 23 rotates, the charged developer is transported from one communicating portion provided in the partition 22b to the second transport path 22d, and the developer passes through the first transport path 22c and the second transport path 22d. Circulate. Then, the developer is supplied from the second stirring member 24 to the developing roller 27.

現像ローラ27は、固定磁石体25と現像スリーブ26とを備える。現像スリーブ26は、円筒状の非磁性材からなり、第2撹拌部材24に隣接する位置で現像容器22に回転可能に支持される。固定磁石体25は、現像スリーブ26内に固設される永久磁石からなり、現像スリーブ26に向けて磁界を発生する。また、現像ローラ27は、現像容器22の開口から露出し、像担持体である感光体11に一定の間隔を隔てて対向している。この対向する領域は、現像スリーブ26上に担持されている現像剤を感光体11に向けて供給するための現像領域Dとなっている。更に、現像スリーブ26には、トナーを感光体11に供給するために、直流に交流を重畳した現像バイアス29が印加される。   The developing roller 27 includes a fixed magnet body 25 and a developing sleeve 26. The developing sleeve 26 is made of a cylindrical nonmagnetic material and is rotatably supported by the developing container 22 at a position adjacent to the second stirring member 24. The fixed magnet body 25 is a permanent magnet fixed in the developing sleeve 26 and generates a magnetic field toward the developing sleeve 26. Further, the developing roller 27 is exposed from the opening of the developing container 22 and faces the photosensitive member 11 that is an image carrier at a predetermined interval. This facing area is a developing area D for supplying the developer carried on the developing sleeve 26 toward the photoreceptor 11. Further, a developing bias 29 in which alternating current is superimposed on direct current is applied to the developing sleeve 26 in order to supply toner to the photoreceptor 11.

規制部材28は、現像スリーブ26表面に担持される現像剤を所定の層厚に規制するものであり、ブレード状をなし現像スリーブ26の略上方で現像スリーブ26表面との間に所定間隔を設けて、現像容器22に取り付けられる。   The regulating member 28 regulates the developer carried on the surface of the developing sleeve 26 to a predetermined layer thickness. The regulating member 28 has a blade shape and has a predetermined interval between the developing sleeve 26 and the surface of the developing sleeve 26. And attached to the developing container 22.

現像スリーブ26内の固定磁石体25の磁力により、第2撹拌部材24から供給された現像剤が現像スリーブ26表面に担持される。担持された現像剤は、規制部材28により所定の層厚に規制され、現像スリーブ26の矢印方向の回転により、現像流域Dに向けて搬送される。現像スリーブ26に現像バイアス29が印加されることにより、現像領域Dにおいて現像スリーブ26と感光体11との間に電位差が発生し、現像スリーブ26上のトナーは感光体11に供給され、感光体11上の静電潜像はトナー像に現像される。   The developer supplied from the second stirring member 24 is carried on the surface of the developing sleeve 26 by the magnetic force of the fixed magnet body 25 in the developing sleeve 26. The carried developer is regulated to a predetermined layer thickness by the regulating member 28, and is conveyed toward the developing flow area D by the rotation of the developing sleeve 26 in the arrow direction. When a developing bias 29 is applied to the developing sleeve 26, a potential difference is generated between the developing sleeve 26 and the photoconductor 11 in the developing region D, and the toner on the developing sleeve 26 is supplied to the photoconductor 11 and the photoconductor. The electrostatic latent image on 11 is developed into a toner image.

次に、図3を用いて現像装置の撹拌部について詳しく説明する。図3は撹拌部の断面を上側から見た現像装置の平面図である。   Next, the stirring unit of the developing device will be described in detail with reference to FIG. FIG. 3 is a plan view of the developing device as seen from above the cross section of the stirring unit.

現像容器22には、前述のように第1搬送路22cと、第2搬送路22dと、仕切り部22bと、連通部22e、22fが形成され、その他に、現像剤補給口22g(図4も参照)と、現像剤排出口22h(図4参照)が形成されている。   As described above, the developer container 22 is formed with the first transport path 22c, the second transport path 22d, the partition 22b, and the communication sections 22e and 22f. In addition, the developer supply port 22g (see FIG. 4). And a developer discharge port 22h (see FIG. 4).

現像容器22の仕切り部22bは、現像容器22の長手方向に延びて第1搬送路22cと第2搬送路22dを並列させるように仕切っている。仕切り部22bの長手方向の両端部分には、連通部22e、22fが設けられており、現像剤は、第1搬送路22cと、連通部22eと、第2搬送路22d、及び連通部22f内を循環することが可能である。   The partition 22b of the developing container 22 extends in the longitudinal direction of the developing container 22 and partitions the first transport path 22c and the second transport path 22d in parallel. Communication portions 22e and 22f are provided at both end portions in the longitudinal direction of the partition portion 22b, and the developer is contained in the first conveyance path 22c, the communication section 22e, the second conveyance path 22d, and the communication section 22f. It is possible to circulate.

第1搬送路22c内には第1撹拌部材23が配設され、第2搬送路22d内には第2撹拌部材24が配設されている。   A first stirring member 23 is disposed in the first transport path 22c, and a second stirring member 24 is disposed in the second transport path 22d.

第1撹拌部材23は、回転軸23bと、第1螺旋羽根23aと、撹拌リブ23cと、逆螺旋羽根23dとを有する。   The 1st stirring member 23 has the rotating shaft 23b, the 1st spiral blade 23a, the stirring rib 23c, and the reverse spiral blade 23d.

回転軸23bは現像容器22の側壁に回転可能に軸支されている。第1螺旋羽根23aは、回転軸23bに一体に設けられ、回転軸23bの軸方向に一定のピッチで螺旋状に形成されている。また、第1螺旋羽根23aは、第1搬送路22cの長手方向に延び、連通部22fに対向して設けられている。撹拌リブ23cは、平板状をなして各第1螺旋羽根23aの間に配置され、回転軸23bに一体に設けられる。この撹拌リブ23cによって、現像剤は、第1搬送路22c内を搬送される間に一層良く撹拌される。逆螺旋羽根23dは、第1螺旋羽根23aとは逆方向の位相を有する羽根で少なくとも1ピッチ分形成され、連通部22eに対向して回転軸23bに一体に設けられる。逆螺旋羽根23dが回転すると、第1搬送路22c内で下流側(図3の右側)に搬送された現像剤は、連通部22eから第2搬送路22dに搬送されることになる。   The rotation shaft 23 b is rotatably supported on the side wall of the developing container 22. The first spiral blades 23a are provided integrally with the rotation shaft 23b, and are formed in a spiral shape at a constant pitch in the axial direction of the rotation shaft 23b. The first spiral blade 23a extends in the longitudinal direction of the first transport path 22c and is provided to face the communication portion 22f. The stirring rib 23c is formed between the first spiral blades 23a in a flat plate shape, and is provided integrally with the rotating shaft 23b. By this stirring rib 23c, the developer is further stirred while being transported in the first transport path 22c. The reverse spiral blade 23d is a blade having a phase opposite to that of the first spiral blade 23a and is formed at least by one pitch, and is provided integrally with the rotation shaft 23b so as to face the communication portion 22e. When the reverse spiral blade 23d rotates, the developer conveyed to the downstream side (right side in FIG. 3) in the first conveyance path 22c is conveyed from the communication portion 22e to the second conveyance path 22d.

第2撹拌部材24は、回転軸24bと、第2螺旋羽根24aと、逆螺旋羽根24dとを有する。   The second stirring member 24 has a rotating shaft 24b, a second spiral blade 24a, and a reverse spiral blade 24d.

回転軸24bは、回転軸23bと並列して配置され、現像容器22の側壁に回転可能に軸支されている。第2螺旋羽根24aは、回転軸24bに一体に設けられ、回転軸24bの軸方向に一定のピッチで螺旋状に形成されている。また、第2螺旋羽根24aは、第2搬送路22d内で現像ローラ27の軸方向長さ以上に延びて設けられ、更に連通部22eに対向して設けられている。逆螺旋羽根24dは、第2螺旋羽根24aとは逆方向の位相を有する羽根で少なくとも1ピッチ分形成され、連通部22fに対向して回転軸24bに一体に設けられる。逆螺旋羽根24dが回転すると、第2搬送路22d内で下流側(図3の左側)に搬送された現像剤は、連通部22fから第1搬送路22cに搬送されることになる。   The rotating shaft 24b is disposed in parallel with the rotating shaft 23b and is rotatably supported on the side wall of the developing container 22. The second spiral blades 24a are provided integrally with the rotary shaft 24b, and are formed in a spiral shape at a constant pitch in the axial direction of the rotary shaft 24b. The second spiral blade 24a is provided so as to extend beyond the axial length of the developing roller 27 in the second conveyance path 22d, and is provided to face the communication portion 22e. The reverse spiral blade 24d is a blade having a phase opposite to that of the second spiral blade 24a, and is formed for at least one pitch, and is provided integrally with the rotating shaft 24b so as to face the communication portion 22f. When the reverse spiral blade 24d rotates, the developer conveyed to the downstream side (left side in FIG. 3) in the second conveyance path 22d is conveyed from the communication portion 22f to the first conveyance path 22c.

従って、現像時に、図示しないモータ、歯車列等の駆動源によって、回転軸23bが回転すると、回転軸23bとともに第1螺旋羽根23aが回転し、第1螺旋羽根23aは第1搬送路22c内の現像剤を矢印P方向に搬送する。回転軸23bと連動して、回転軸24bが回転軸23bと同じ回転速度で逆回転すると、第2螺旋羽根24aは第2搬送路22d内の現像剤を矢印Q方向に搬送し、現像剤は、第1搬送路22cから、順に連通部22e、第2搬送路22d、及び連通部22fと循環しながら撹拌される。そして、第2搬送路22dから現像剤が現像ローラ27の軸方向に均一に供給される。   Accordingly, when the rotating shaft 23b is rotated by a driving source such as a motor or a gear train (not shown) during development, the first spiral blade 23a rotates together with the rotating shaft 23b, and the first spiral blade 23a is in the first transport path 22c. The developer is conveyed in the direction of arrow P. When the rotary shaft 24b is reversely rotated at the same rotational speed as the rotary shaft 23b in conjunction with the rotary shaft 23b, the second spiral blade 24a transports the developer in the second transport path 22d in the direction of the arrow Q. From the first transport path 22c, stirring is performed while circulating through the communication portion 22e, the second transport path 22d, and the communication portion 22f in order. Then, the developer is uniformly supplied from the second transport path 22d in the axial direction of the developing roller 27.

次に、新たな現像剤の補給と余剰現像剤の排出について図3〜図6を用いて説明する。図4は撹拌部における現像剤補給口と現像剤排出口との上下方向の配置を模式的に示す平面図であり、図5は現像剤補給口から現像剤を供給している状態を示す断面側面図であり、図6は、現像剤補給口を示す断面側面図である。   Next, replenishment of new developer and discharge of excess developer will be described with reference to FIGS. FIG. 4 is a plan view schematically showing the vertical arrangement of the developer supply port and the developer discharge port in the agitation section, and FIG. 5 is a cross section showing a state where the developer is supplied from the developer supply port. FIG. 6 is a side view, and FIG. 6 is a cross-sectional side view showing a developer supply port.

図3に示すように、新たな現像剤の補給と余剰現像剤の排出とを行うために、現像容器22の周辺には、現像剤補給口22gと、現像剤排出口22h(図4、図5参照)と、補給搬送部材である磁気ローラ52と、搬送スクリュー51と、搬送パイプ53が設けられる。   As shown in FIG. 3, in order to supply a new developer and discharge a surplus developer, a developer supply port 22g and a developer discharge port 22h (FIG. 4, FIG. 5), a magnetic roller 52 which is a replenishment conveying member, a conveying screw 51, and a conveying pipe 53 are provided.

現像剤補給口22gは、現像容器22内に新たな現像剤を供給するための開口であり、第1搬送路22cの上流側(図3の左側)で現像容器22の長手方向の側壁22pに形成される。   The developer supply port 22g is an opening for supplying a new developer into the developer container 22, and is provided on the side wall 22p in the longitudinal direction of the developer container 22 on the upstream side (left side in FIG. 3) of the first transport path 22c. It is formed.

現像剤排出口22h(図5参照)は、現像剤の補給によって現像容器22内で余剰となった現像剤を排出するための開口であり、現像容器22の長手方向の側壁22pに形成され、更に、現像剤補給口22gの近傍に形成される(図4参照)。   The developer discharge port 22h (see FIG. 5) is an opening for discharging the developer remaining in the developer container 22 due to replenishment of the developer, and is formed on the side wall 22p in the longitudinal direction of the developer container 22. Further, it is formed in the vicinity of the developer supply port 22g (see FIG. 4).

図4に示すように、現像剤排出口22hは第1撹拌部材23の回転軸23bより上側に配置され、現像剤補給口22gは、現像剤排出口22hに対して下側で現像剤搬送方向(図4の矢印方向)の下流側の近傍位置に配置される。尚、現像剤搬送方向において、現像剤補給口22gの開口幅は現像剤排出口22hの開口幅と略同じ大きさに形成されている。   As shown in FIG. 4, the developer discharge port 22h is arranged above the rotation shaft 23b of the first stirring member 23, and the developer supply port 22g is below the developer discharge port 22h and in the developer transport direction. It is arranged at a position near the downstream side (in the direction of the arrow in FIG. 4). In the developer transport direction, the opening width of the developer supply port 22g is formed to be approximately the same as the opening width of the developer discharge port 22h.

図3に戻り、搬送パイプ53は、ホッパー110(図1参照)と現像剤補給口22gとを連結し、ホッパー110から現像剤補給口22gに現像剤を通す管であり、搬送スクリュー51と磁気ローラ52とを回転可能に軸支している。   Returning to FIG. 3, the transport pipe 53 is a pipe that connects the hopper 110 (see FIG. 1) and the developer supply port 22 g and passes the developer from the hopper 110 to the developer supply port 22 g. The roller 52 is rotatably supported.

搬送スクリュー51は、回転軸に一体に設けられその軸方向に一定のピッチで螺旋状に形成された羽根を有し、回転するとホッパー110の現像剤を撹拌しながら磁気ローラ52側に搬送する。   The conveyance screw 51 is provided integrally with the rotation shaft and has blades formed in a spiral shape at a constant pitch in the axial direction. When the conveyance screw 51 rotates, the developer in the hopper 110 is conveyed to the magnetic roller 52 side while stirring.

磁気ローラ52は、現像剤補給口22gを介して搬送パイプ53内の現像剤を現像容器22内に搬送するものであり、搬送スクリュー51の回転軸と一体に設けられ、永久磁石等の磁性体からなる。従って、磁気ローラ52の外周面には磁界が生成され、搬送スクリュー51から磁気ローラ52に現像剤が搬送されると、磁気ローラ52の外周面に現像剤が付着し磁気ブラシを形成する。また、磁気ローラ52は現像剤補給口22gの近くで対向して配置される。磁気ローラ52が回転すると、磁気ローラ52上の現像剤が現像剤補給口22g側に搬送されるとともに、磁気ローラ52上の磁気ブラシにて現像容器22内の現像剤が現像剤補給口22gから搬送パイプ53に戻るのが防止される。   The magnetic roller 52 transports the developer in the transport pipe 53 into the developing container 22 through the developer supply port 22g, and is provided integrally with the rotating shaft of the transport screw 51, and is a magnetic material such as a permanent magnet. Consists of. Accordingly, a magnetic field is generated on the outer peripheral surface of the magnetic roller 52, and when the developer is transported from the transport screw 51 to the magnetic roller 52, the developer adheres to the outer peripheral surface of the magnetic roller 52 to form a magnetic brush. Further, the magnetic roller 52 is disposed oppositely near the developer supply port 22g. When the magnetic roller 52 rotates, the developer on the magnetic roller 52 is conveyed to the developer supply port 22g side, and the developer in the developer container 22 is transferred from the developer supply port 22g by the magnetic brush on the magnetic roller 52. Returning to the transport pipe 53 is prevented.

図5を用いて現像剤の補給と排出について詳しく説明する。前述のように、現像剤補給口22gは現像剤排出口22hの下側に配置される。第1撹拌部材23は矢印K方向に回転し、磁気ローラ52は第1撹拌部材23と同じく矢印M方向に回転する。   The developer replenishment and discharge will be described in detail with reference to FIG. As described above, the developer supply port 22g is disposed below the developer discharge port 22h. The first stirring member 23 rotates in the direction of arrow K, and the magnetic roller 52 rotates in the direction of arrow M, like the first stirring member 23.

磁気ローラ52の矢印M方向に回転によって、搬送パイプ53内の現像剤は現像剤補給口22gの下側から現像容器22内に向けて搬送される。そして、磁気ローラ52にて現像容器22内に向けて搬送された現像剤は、第1撹拌部材23が矢印K方向に回転することにより、第1撹拌部材23の下側を通って(矢印Z方向を通って)第1撹拌部材23に対して現像剤補給口22gの反対側の第1搬送路22cに搬送される。また、第1撹拌部材23の矢印K方向の回転により、現像剤は第1搬送路22c内で現像剤搬送方向の下流側(図3の矢印P方向側)に搬送され、更に、連通部22e(図3参照)から第2搬送路22dへ搬送され、現像ローラ27に供給される。   By the rotation of the magnetic roller 52 in the arrow M direction, the developer in the transport pipe 53 is transported from the lower side of the developer supply port 22g toward the developer container 22. Then, the developer conveyed toward the developing container 22 by the magnetic roller 52 passes under the first stirring member 23 (arrow Z) as the first stirring member 23 rotates in the arrow K direction. (Through the direction), the first agitating member 23 is conveyed to the first conveying path 22c opposite to the developer supply port 22g. Further, the rotation of the first agitating member 23 in the direction of arrow K causes the developer to be transported downstream (in the direction of arrow P in FIG. 3) in the developer transport direction within the first transport path 22c, and further to the communication portion 22e. (Refer to FIG. 3) is conveyed to the second conveyance path 22d and supplied to the developing roller 27.

また、磁気ローラ52が第1撹拌部材23と同じ方向に回転することで、磁気ローラ52と第1撹拌部材23とが対向する現像剤補給口22g近傍では、磁気ローラ52と第1撹拌部材23とが対向面において互いに逆方向に移動する。つまり、磁気ローラ52は現像剤補給口22g側から現像剤排出口22h側に向かって回転することなり、これによって、第1搬送路22cの現像剤補給口22gの上側近傍では現像剤が上側に持ち上がり、現像剤補給口22gの上側に配置される現像剤排出口22hの現像剤の嵩が高くなる。この現像剤は、第1撹拌部材23にて第1搬送路22c内の上流側、つまり第2搬送路22d(図3参照)側から搬送され現像に供されたものを多く含むものであり、余剰現像剤として現像剤排出口22hを乗り越えて排出パイプ58に排出される。そして、排出パイプ58内に回転可能に設けられた排出スクリュー56にて図示しない現像剤回収部に搬送される。   Further, when the magnetic roller 52 rotates in the same direction as the first stirring member 23, the magnetic roller 52 and the first stirring member 23 are in the vicinity of the developer supply port 22g where the magnetic roller 52 and the first stirring member 23 face each other. Move in opposite directions on the facing surface. In other words, the magnetic roller 52 rotates from the developer supply port 22g side toward the developer discharge port 22h side, so that the developer is moved upward in the vicinity of the upper side of the developer supply port 22g of the first conveyance path 22c. As a result, the developer becomes bulky at the developer discharge port 22h disposed above the developer supply port 22g. This developer contains a large amount of developer that is conveyed from the upstream side in the first conveyance path 22c by the first agitating member 23, that is, from the second conveyance path 22d (see FIG. 3) side and used for development. As a surplus developer, the developer passes over the developer discharge port 22h and is discharged to the discharge pipe 58. Then, the toner is conveyed to a developer recovery unit (not shown) by a discharge screw 56 rotatably provided in the discharge pipe 58.

図6に示すように、現像剤が搬送スクリュー51(図3参照)から磁気ローラ52に搬送されると、磁気ローラ52表面に現像剤が付着し磁気ブラシBが形成される。ここで、現像剤補給口22gと磁気ローラ52との隙間は磁気ローラ52の上側と下側で均等ではなく、偏っている。つまり、磁気ローラ52に対して現像剤補給口22gの下側の隙間(磁気ローラ52の法線方向における磁気ローラ52の外周面と現像剤補給口22gとの長さY)を比較的に大きくし、現像剤が十分に通過できるようにしておく。   As shown in FIG. 6, when the developer is transported from the transport screw 51 (see FIG. 3) to the magnetic roller 52, the developer adheres to the surface of the magnetic roller 52 and the magnetic brush B is formed. Here, the gap between the developer supply port 22g and the magnetic roller 52 is not uniform on the upper side and the lower side of the magnetic roller 52 but is biased. That is, the gap below the developer supply port 22g with respect to the magnetic roller 52 (the length Y between the outer peripheral surface of the magnetic roller 52 and the developer supply port 22g in the normal direction of the magnetic roller 52) is relatively large. The developer is allowed to pass sufficiently.

一方、磁気ローラ52に対して現像剤補給口22gの上側の隙間(磁気ローラ52の法線方向における磁気ローラ52の外周面と現像剤補給口22gとの長さX)を磁気ブラシBの高さ相当の長さとしておくことによって、磁気ローラ52の矢印M方向の回転に伴い、第1搬送路22c内の現像剤が搬送パイプ53に逆流しないようにしている。   On the other hand, the gap above the developer supply port 22g with respect to the magnetic roller 52 (the length X between the outer peripheral surface of the magnetic roller 52 and the developer supply port 22g in the normal direction of the magnetic roller 52) is set to the height of the magnetic brush B. By setting the length to an appropriate length, the developer in the first transport path 22 c does not flow backward to the transport pipe 53 as the magnetic roller 52 rotates in the direction of arrow M.

つまり、磁気ローラ52が矢印M方向に回転すると、搬送パイプ53内の現像剤は現像剤補給口22gの下側から現像容器22内に向けて搬送される。また、磁気ローラ52が矢印M方向に回転すると、磁気ローラ52の回転にともない、第1搬送路22c内における現像剤補給口22gの近傍の現像剤は現像剤補給口22gから搬送パイプ53内に戻ろうとするが、この現像剤は磁気ブラシBにて阻止され第1搬送路22c内から搬送パイプ53内に戻ることはない。   That is, when the magnetic roller 52 rotates in the direction of arrow M, the developer in the transport pipe 53 is transported from the lower side of the developer supply port 22g toward the developer container 22. When the magnetic roller 52 rotates in the direction of arrow M, the developer near the developer supply port 22g in the first transport path 22c moves into the transport pipe 53 from the developer supply port 22g as the magnetic roller 52 rotates. Although the developer tries to return, the developer is blocked by the magnetic brush B and does not return from the first transport path 22 c into the transport pipe 53.

次に、本実施形態において現像剤排出口22hから排出される現像剤の帯電量を比較例とともに評価する。   Next, the charge amount of the developer discharged from the developer discharge port 22h in this embodiment is evaluated together with a comparative example.

図7は比較例に係る撹拌部を模式的に示す平面図である。比較例の第1撹拌部材23、現像剤排出口22hの配置、構成、及び開口幅は図4に示す本実施形態と同じであり、現像剤は図7の矢印方向に搬送される。また比較例では、現像剤排出口22hと同じサイズの開口を有する現像剤補給口22gが現像剤排出口22hに対して現像剤搬送方向の下流側に配置され、また、現像剤排出口22hと同じ高さ(第1搬送路22cの底面から同じ高さ)に配置される。また、比較例には磁気ローラ52が配設されていない。   FIG. 7 is a plan view schematically showing a stirring unit according to a comparative example. The arrangement, configuration, and opening width of the first stirring member 23 and the developer discharge port 22h of the comparative example are the same as those of the present embodiment shown in FIG. 4, and the developer is conveyed in the direction of the arrow in FIG. In the comparative example, a developer supply port 22g having an opening of the same size as the developer discharge port 22h is disposed on the downstream side of the developer discharge port 22h in the developer transport direction, and the developer discharge port 22h It arrange | positions at the same height (the same height from the bottom face of the 1st conveyance path 22c). In the comparative example, the magnetic roller 52 is not provided.

本実施形態及び比較例の構成において、夫々、印字率4%の原稿を100×103枚印字した後に、新しい現像剤を現像剤補給口22gから現像容器22内に供給し第1及び第2撹拌部材23、24を回転させる。そして現像剤排出口22hから溢れ出た現像剤を採取し、帯電量分布測定装置(イースパートアナライザ、ホソカワミクロン社製)にて帯電量分布を測定した。 In the configuration of this embodiment and the comparative example, after printing 100 × 10 3 originals with a printing rate of 4%, new developer is supplied into the developer container 22 from the developer supply port 22g, and the first and second developers are supplied. The stirring members 23 and 24 are rotated. The developer overflowing from the developer discharge port 22h was collected, and the charge amount distribution was measured with a charge amount distribution measuring device (Espert Analyzer, manufactured by Hosokawa Micron Corporation).

その測定結果を図8に示す。図8のグラフでは、横軸に帯電量(単位;nC/m)、縦軸に各帯電量における現像剤が発生する頻度(単位;%)を取っている。図8において、帯電量が0nC/m以下である現像剤が発生する頻度を本実施形態と比較例とで比較してみると、比較例ではその頻度が5.7%であるのに対して、本実施形態ではその頻度が28.7%であった。   The measurement results are shown in FIG. In the graph of FIG. 8, the horizontal axis represents the charge amount (unit: nC / m), and the vertical axis represents the frequency (unit:%) at which the developer is generated at each charge amount. In FIG. 8, when comparing the frequency of occurrence of the developer having a charge amount of 0 nC / m or less between this embodiment and the comparative example, the frequency in the comparative example is 5.7%. In this embodiment, the frequency is 28.7%.

つまり本実施形態では、帯電量が0nC/m以下、つまり帯電性能が劣化している現像剤を比較例に対して多く排出し、良好な現像剤の排出が抑えられていることになる。   That is, in this embodiment, a large amount of developer with a charge amount of 0 nC / m or less, that is, with a deteriorated charging performance, is discharged relative to the comparative example, and the discharge of good developer is suppressed.

上記第1実施形態によれば、現像装置14は、現像剤を収容する現像容器22と、この現像容器22に回転可能に軸支され現像容器22内の現像剤を撹拌、搬送する撹拌部材23と、現像容器22内に現像剤を供給する現像剤補給口22gと、現像容器22の外側から現像剤補給口22gに対向して配置され現像剤補給口22gから現像容器22内に現像剤を搬送する磁気ローラ52(補給搬送部材)と、現像容器22内の余剰の現像剤が排出される現像剤排出口22hとを備える。現像剤排出口22hは現像容器22の長手方向の側壁22pに形成され、現像剤補給口22gは現像剤排出口22hの下側近傍に形成され、撹拌部材23は現像剤排出口22h側から現像剤補給口22g側に向けて回転し、磁気ローラ52は撹拌部材23と同じ方向に回転する。   According to the first embodiment, the developing device 14 includes the developing container 22 that stores the developer, and the stirring member 23 that is rotatably supported by the developing container 22 and stirs and conveys the developer in the developing container 22. A developer replenishing port 22g for supplying the developer into the developing container 22, and a developer replenishing port 22g that is arranged to face the developer replenishing port 22g from the outside of the developing container 22, and the developer is supplied into the developing container 22 A magnetic roller 52 (a replenishment conveyance member) for conveyance and a developer discharge port 22h for discharging excess developer in the developer container 22 are provided. The developer discharge port 22h is formed in the longitudinal side wall 22p of the developer container 22, the developer supply port 22g is formed near the lower side of the developer discharge port 22h, and the stirring member 23 is developed from the developer discharge port 22h side. The magnetic roller 52 rotates in the same direction as the stirring member 23. The magnetic roller 52 rotates toward the agent supply port 22g.

この構成によると、現像剤が現像剤補給口22gから現像容器22内に供給されるときに、撹拌部材23が現像剤排出口22h側から現像剤補給口22g側に向けて回転するために、供給された現像剤は現像容器22内で現像剤補給口22g側から撹拌部材23に対して現像剤補給口22gの反対側に搬送され、更に、撹拌部材23の回転にともない現像容器22の長手方向に搬送される。このように現像剤補給口22gから供給された現像剤は現像剤排出口22hに直ちに搬送されることはない。また、現像容器22内の現像剤補給口22gの上側近傍では、撹拌部材23と磁気ローラ52とが対向面において互いに逆方向に移動し、つまり磁気ローラ52が現像剤補給口22g側から現像剤排出口22h側に向かって回転することによって、現像容器22内の現像剤補給口22gの上側近傍では現像剤が上側に持ち上がり、現像剤補給口22gの上側に配置される現像剤排出口22hの現像剤の嵩が高くなる。この嵩が高くなった現像剤は、撹拌部材23によって搬送方向の上流側から搬送されるものであり、現像剤排出口22hから余剰現像剤として排出される。従って、現像剤補給口22gから供給されたばかりの現像剤が現像剤排出口22hから排出されることを抑えることができる。   According to this configuration, when the developer is supplied into the developer container 22 from the developer supply port 22g, the stirring member 23 rotates from the developer discharge port 22h side toward the developer supply port 22g side. The supplied developer is conveyed in the developing container 22 from the developer supply port 22g side to the side opposite to the developer supply port 22g with respect to the stirring member 23. Further, as the stirring member 23 rotates, the length of the developer container 22 is increased. Conveyed in the direction. Thus, the developer supplied from the developer supply port 22g is not immediately conveyed to the developer discharge port 22h. Further, in the vicinity of the upper side of the developer supply port 22g in the developer container 22, the stirring member 23 and the magnetic roller 52 move in opposite directions on the opposing surface, that is, the magnetic roller 52 moves from the developer supply port 22g side to the developer. By rotating toward the discharge port 22h, the developer is lifted upward in the vicinity of the developer supply port 22g in the developer container 22, and the developer discharge port 22h disposed above the developer supply port 22g. The bulk of the developer increases. The developer having increased bulk is transported from the upstream side in the transport direction by the stirring member 23, and is discharged as an excess developer from the developer discharge port 22h. Therefore, it is possible to prevent the developer just supplied from the developer supply port 22g from being discharged from the developer discharge port 22h.

また、上記第1実施形態によれば、現像剤補給口22gの上端縁と磁気ローラ52との隙間Xは磁気ローラ52上に形成される磁気ブラシの高さと略等しく、現像剤補給口22gの下端縁と磁気ローラとの隙間Yは磁気ブラシの高さよりも大きい。   Further, according to the first embodiment, the gap X between the upper end edge of the developer supply port 22g and the magnetic roller 52 is substantially equal to the height of the magnetic brush formed on the magnetic roller 52, and the developer supply port 22g The gap Y between the lower edge and the magnetic roller is larger than the height of the magnetic brush.

この構成によると、現像剤補給口22gの上端縁と磁気ローラ52との隙間Xが磁気ブラシの高さと略等しいので、現像容器22に供給された現像剤が現像剤補給口22g内に戻ることを確実に防止するとともに、現像剤補給口22gの下端縁と磁気ローラとの隙間Yが磁気ブラシの高さよりも大きいので、現像剤補給口22gから現像容器22内に現像剤を十分に供給することができる。   According to this configuration, since the gap X between the upper end edge of the developer supply port 22g and the magnetic roller 52 is substantially equal to the height of the magnetic brush, the developer supplied to the developer container 22 returns into the developer supply port 22g. Since the gap Y between the lower edge of the developer supply port 22g and the magnetic roller is larger than the height of the magnetic brush, the developer is sufficiently supplied into the developer container 22 from the developer supply port 22g. be able to.

また、上記第1実施形態によれば、現像剤補給口22gは、現像剤排出口22hに対して下側で且つ撹拌部材23の現像剤搬送方向の下流側に配置される。これによって、現像剤補給口22gから現像容器22内に供給された現像剤は、現像剤排出口22hに直ちに搬送されることがなく、撹拌部材23の回転にともない現像容器22の長手方向に確実に搬送される。   Further, according to the first embodiment, the developer supply port 22g is disposed below the developer discharge port 22h and downstream of the stirring member 23 in the developer transport direction. As a result, the developer supplied into the developer container 22 from the developer supply port 22g is not immediately conveyed to the developer discharge port 22h, and the developer container 22 is reliably moved in the longitudinal direction as the stirring member 23 rotates. It is conveyed to.

(第2実施形態)
図9は、第2実施形態に係る撹拌部を模式的に示す平面図である。第2実施形態では、現像剤排出口22hは第1撹拌部材23の回転軸23bより上側に配置され、現像剤補給口22gは、現像剤排出口22hに対して下側で現像剤搬送方向(図4の矢印方向)で同じ位置に配置される。図示しない磁気ローラ52は、第1実施形態と同様に、搬送パイプ53(図6参照)内で現像剤補給口22g近傍に回転可能に配設され、また、現像剤補給口22gは磁気ローラ52との隙間を上下方向に対して偏らせて形成されている。尚、現像剤搬送方向において、現像剤補給口22gの開口幅は現像剤排出口22hの開口幅よりも長く形成され、現像剤補給口22gは現像剤排出口22hよりも現像剤搬送方向の下流側に延在するように形成されている。
(Second Embodiment)
FIG. 9 is a plan view schematically showing a stirring unit according to the second embodiment. In the second embodiment, the developer discharge port 22h is disposed above the rotation shaft 23b of the first stirring member 23, and the developer supply port 22g is below the developer discharge port 22h in the developer transport direction ( (In the direction of the arrow in FIG. 4). The magnetic roller 52 (not shown) is rotatably disposed in the vicinity of the developer supply port 22g in the transport pipe 53 (see FIG. 6), as in the first embodiment, and the developer supply port 22g is provided in the magnetic roller 52. The gap is formed so as to be biased with respect to the vertical direction. In the developer transport direction, the opening width of the developer supply port 22g is formed longer than the opening width of the developer discharge port 22h, and the developer supply port 22g is downstream of the developer discharge port 22h in the developer transport direction. It is formed to extend to the side.

この構成によると、磁気ローラ52が現像剤補給口22g側から現像剤排出口22h側に向かって回転することによって、現像容器22内の現像剤補給口22gの上側近傍では現像剤が上側に持ち上がり、現像剤補給口22gの上側に配置される現像剤排出口22hの現像剤の嵩が十分に高くなり、余剰現像剤を現像剤排出口22hから確実に排出させることができる。   According to this configuration, when the magnetic roller 52 rotates from the developer supply port 22g side toward the developer discharge port 22h side, the developer is lifted upward in the vicinity of the developer supply port 22g in the developer container 22. The bulk of the developer at the developer discharge port 22h disposed on the upper side of the developer supply port 22g becomes sufficiently high, and the excess developer can be reliably discharged from the developer discharge port 22h.

尚、上記第1及び第2実施形態では、補給搬送部材を磁気ローラ52にて構成したが、本発明はこれに限らず、搬送パイプ53内に配設した搬送スクリュー51を現像剤補給口22gに対向する位置にまで延ばし、この搬送スクリュー51にて補給搬送部材を構成するようにしてもよい。また、補給搬送部材は回転軸の周りにパドル状の羽根を有するように構成してもよい。これらの場合も上記第1及び第2実施形態と同様に、現像剤補給口22gから供給されたばかりの現像剤が現像剤排出口22hから排出されることを抑えることができる。   In the first and second embodiments, the replenishing and conveying member is configured by the magnetic roller 52. However, the present invention is not limited to this, and the conveying screw 51 disposed in the conveying pipe 53 is connected to the developer supply port 22g. The supply screw 51 may be configured by the conveyance screw 51. Further, the replenishment conveying member may be configured to have paddle-shaped blades around the rotation axis. In these cases, similarly to the first and second embodiments, it is possible to prevent the developer just supplied from the developer supply port 22g from being discharged from the developer discharge port 22h.

また、上記第1及び第2実施形態では、現像剤補給口22g及び現像剤排出口22hを第1搬送路22cの上流側に配置する構成を示したが、本発明はこれに限らず、現像剤補給口22g及び現像剤排出口22hを第1搬送路22cの下流側または中央に配置する構成にしてもよいし、また、第2搬送路22dに配置する構成にしてもよい。これらの場合も上記第1及び第2実施形態と同様の効果を奏する。   In the first and second embodiments, the developer supply port 22g and the developer discharge port 22h are arranged on the upstream side of the first transport path 22c. However, the present invention is not limited to this, and the development is performed. The agent supply port 22g and the developer discharge port 22h may be arranged downstream or in the center of the first conveyance path 22c, or may be arranged in the second conveyance path 22d. In these cases, the same effects as those of the first and second embodiments are obtained.

また、上記第1及び第2実施形態では、モノクロ複写機に適用した例を示したが、本発明はこれに限らず、カラー複写機、またはカラープリンタの各色の現像装置に適用してもよい。   In the first and second embodiments, an example is shown in which the present invention is applied to a monochrome copying machine. However, the present invention is not limited to this, and may be applied to a developing device for each color of a color copying machine or a color printer. .

本発明は、電子写真方式を利用した複写機、プリンタ、ファクシミリ、それらの複合機等の画像形成装置に用いる現像装置及びそれを備えた画像形成装置に利用することができ、特に、トナーとキャリアとからなる2成分現像剤の補給を行うとともに余剰現像剤を排出する現像装置及びそれを備えた画像形成装置に利用することができる。   INDUSTRIAL APPLICABILITY The present invention can be used for a developing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, and a composite machine using the electrophotographic method, and an image forming apparatus including the developing device. Can be used for a developing device that replenishes the two-component developer and discharges excess developer and an image forming apparatus equipped with the developing device.

1 画像形成装置
11 感光体(像担持体)
14 現像装置
22 現像容器
22c 第1搬送路
22g 現像剤補給口
22h 現像剤排出口
22p 側壁
23 第1撹拌部材(撹拌部材)
24 第2撹拌部材
27 現像ローラ
51 搬送スクリュー(補給搬送部材)
52 磁気ローラ(補給搬送部材)
53 搬送パイプ
56 排出スクリュー
58 排出パイプ
DESCRIPTION OF SYMBOLS 1 Image forming apparatus 11 Photosensitive body (image carrier)
14 Developing Device 22 Developing Container 22c First Conveying Path 22g Developer Supply Port 22h Developer Discharge Port 22p Side Wall 23 First Stirring Member (Stirring Member)
24 Second stirring member 27 Developing roller 51 Conveying screw (replenishment conveying member)
52 Magnetic roller (replenishment conveying member)
53 Conveying pipe 56 Discharge screw 58 Discharge pipe

Claims (6)

現像剤を収容する現像容器と、前記現像容器に回転可能に軸支され前記現像容器内の現像剤を撹拌、搬送する撹拌部材と、前記現像容器内に現像剤を供給する現像剤補給口と、前記現像容器の外側から前記現像剤補給口に対向して配置され前記現像剤補給口から前記現像容器内に現像剤を搬送する補給搬送部材と、前記現像容器内の余剰の現像剤が排出される現像剤排出口とを備え、
前記現像剤排出口は前記現像容器の長手方向の側壁に形成され、前記現像剤補給口は前記現像剤排出口の下側近傍に形成され、前記撹拌部材は前記現像剤排出口側から前記現像剤補給口側に向けて回転し、前記補給搬送部材は前記撹拌部材と同じ方向に回転することを特徴とする現像装置。
A developer container for containing the developer; a stirring member that is rotatably supported by the developer container and agitates and conveys the developer in the developer container; and a developer replenishing port that supplies the developer into the developer container; A replenishment conveying member disposed opposite to the developer replenishing port from the outside of the developing container and transporting the developer into the developing container from the developer replenishing port, and excess developer in the developing container is discharged A developer discharge port,
The developer discharge port is formed in a side wall in the longitudinal direction of the developer container, the developer supply port is formed near the lower side of the developer discharge port, and the stirring member is connected to the developer from the developer discharge port side. The developing device, wherein the developing device rotates toward the agent replenishing port, and the replenishment conveying member rotates in the same direction as the stirring member.
前記補給搬送部材は表面に磁界を発生させる磁気ローラからなることを特徴とする請求項1に記載の現像装置。   The developing device according to claim 1, wherein the replenishing and conveying member includes a magnetic roller that generates a magnetic field on a surface thereof. 前記現像剤補給口の上端縁と前記磁気ローラとの隙間は前記磁気ローラ上に形成される磁気ブラシの高さと略等しく、前記現像剤補給口の下端縁と前記磁気ローラとの隙間は前記磁気ブラシの高さよりも大きいことを特徴とする請求項2に記載の現像装置。   The gap between the upper edge of the developer supply port and the magnetic roller is substantially equal to the height of the magnetic brush formed on the magnetic roller, and the gap between the lower edge of the developer supply port and the magnetic roller is the magnetic field. The developing device according to claim 2, wherein the developing device is larger than a height of the brush. 前記現像剤補給口は、前記現像剤排出口に対して前記撹拌部材の現像剤搬送方向の下流側に配置されることを特徴とする請求項1〜請求項3のいずれかに記載の現像装置。   4. The developing device according to claim 1, wherein the developer replenishing port is disposed downstream of the stirring member in a developer transport direction with respect to the developer discharge port. 5. . 前記現像剤補給口は、前記現像剤排出口に対して前記撹拌部材の現像剤搬送方向で同じ位置に配置されることを特徴とする請求項1〜請求項3のいずれかに記載の現像装置。   The developing device according to claim 1, wherein the developer supply port is disposed at the same position in the developer transport direction of the stirring member with respect to the developer discharge port. . 請求項1〜請求項5のいずれかに記載の現像装置が搭載された画像形成装置。   An image forming apparatus on which the developing device according to claim 1 is mounted.
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JP2015011288A (en) * 2013-07-01 2015-01-19 富士ゼロックス株式会社 Powder conveying device, developing device, and image forming apparatus

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JP2001290352A (en) * 2000-04-07 2001-10-19 Ricoh Co Ltd Developing device, process cartridge and image forming device
JP2006259166A (en) * 2005-03-16 2006-09-28 Ricoh Co Ltd Developing device, image forming apparatus, and image forming method
JP2010139924A (en) * 2008-12-15 2010-06-24 Konica Minolta Business Technologies Inc Developing device and image forming apparatus

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Publication number Priority date Publication date Assignee Title
JP2001290352A (en) * 2000-04-07 2001-10-19 Ricoh Co Ltd Developing device, process cartridge and image forming device
JP2006259166A (en) * 2005-03-16 2006-09-28 Ricoh Co Ltd Developing device, image forming apparatus, and image forming method
JP2010139924A (en) * 2008-12-15 2010-06-24 Konica Minolta Business Technologies Inc Developing device and image forming apparatus

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015011288A (en) * 2013-07-01 2015-01-19 富士ゼロックス株式会社 Powder conveying device, developing device, and image forming apparatus

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