JP3323369B2 - Development unit - Google Patents
Development unitInfo
- Publication number
- JP3323369B2 JP3323369B2 JP22782095A JP22782095A JP3323369B2 JP 3323369 B2 JP3323369 B2 JP 3323369B2 JP 22782095 A JP22782095 A JP 22782095A JP 22782095 A JP22782095 A JP 22782095A JP 3323369 B2 JP3323369 B2 JP 3323369B2
- Authority
- JP
- Japan
- Prior art keywords
- developer
- toner
- developing sleeve
- developing
- stirring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、複写機やプリンタ
等の電子写真装置における現像ユニットに関し、詳しく
は、二つの攪拌部材で現像剤を攪拌・搬送して現像スリ
ーブ、感光体へと供給する２軸攪拌スクリュータイプの
現像ユニットに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing unit in an electrophotographic apparatus such as a copying machine or a printer, and more specifically, to stir and convey a developer with two stirring members and supply it to a developing sleeve and a photosensitive member. The present invention relates to a two-shaft stirring screw type developing unit.
【０００２】[0002]
【従来の技術】この種の現像ユニットでは、感光体面上
にトナーを供給して現像するための現像スリーブが備え
られているとともに、この現像スリーブの軸線に沿って
二つの現像剤攪拌部材が並設されている。各現像剤攪拌
部材は回転軸と攪拌羽根とからなるスクリュー構造を有
し、互いに軸方向逆向きに現像剤を攪拌・搬送するよう
に構成されている。各現像剤攪拌部材の間には、軸方向
両端において現像剤の連絡通路を形成する仕切部材が設
けられており、これらの連絡通路を介して各現像剤攪拌
部材間での現像剤の受け渡しがなされるようになってい
る。従って、現像剤は各現像剤攪拌部材で攪拌されなが
らループ状に循環し、現像スリーブに近い現像剤攪拌部
材から現像スリーブ、感光体へと供給される。2. Description of the Related Art In a developing unit of this type, a developing sleeve for supplying and developing toner on the surface of a photoreceptor is provided, and two developer stirring members are arranged in parallel along the axis of the developing sleeve. Has been established. Each developer stirring member has a screw structure including a rotating shaft and a stirring blade, and is configured to stir and convey the developer in axially opposite directions. Partition members are formed between the developer stirring members to form developer communication passages at both ends in the axial direction, and transfer of the developer between the developer stirring members is performed through these communication passages. Is to be done. Therefore, the developer circulates in a loop while being stirred by the respective developer stirring members, and is supplied from the developer stirring member near the developing sleeve to the developing sleeve and the photosensitive member.
【０００３】[0003]
【発明が解決しようとする課題】ところで、この種の現
像ユニット内に収容される現像剤は、キャリアと呼ばれ
る小さな鉄球と、トナーよりなる二成分構成であり、攪
拌によるキャリアの摩擦帯電でキャリアに付着している
トナーの比電荷（Ｑ／Ｍ）を上げるようになっている
が、上述のような従来の現像剤攪拌構成では、トナーの
比電荷（Ｑ／Ｍ）の立ち上げ能力が十分ではない。この
ため、Ｑ／Ｍの不安定な（低い）トナーが残存し、これ
が感光体面上の地肌部に当たる所（本来トナーが付着し
てはならない所）に付着し、画像上にいわゆる「地肌汚
れ」が発生する、という問題があった。The developer contained in this type of developing unit has a two-component structure comprising a small iron ball called a carrier and toner, and the carrier is charged by frictional charging of the carrier by stirring. Although the specific charge (Q / M) of the toner attached to the toner is increased, the conventional developer stirring configuration as described above has a sufficient ability to raise the specific charge (Q / M) of the toner. is not. For this reason, unstable (low) toner of Q / M remains and adheres to a portion of the photoreceptor surface that hits a background portion (a portion where toner should not originally adhere). Occurs.
【０００４】本発明は、このような地肌汚れの発生を抑
制でき、画像品質の向上を図ることができる現像ユニッ
トの提供を、その目的とする。An object of the present invention is to provide a developing unit capable of suppressing the occurrence of such background contamination and improving image quality.
【０００５】[0005]
【課題を解決するための手段】本発明は、現像剤の循環
流れに圧縮率の高い部分を設けてトナー比電荷を上昇さ
せ、Ｑ／Ｍが十分に立ち上げられた現像剤を循環流れに
再び組み入れて現像剤の全体的な比電荷の立ち上がりを
得る、という考えに立っている。この考えの下、請求項
１記載の発明では、感光体面上へトナーを供給して現像
するための現像スリーブと、この現像スリーブの軸線方
向に沿って延び前後反対方向に現像剤を攪拌・搬送する
二つの現像剤攪拌部材を設け、現像スリーブに近い方を
第１の現像剤攪拌部材、遠い方を第２の現像剤攪拌部材
とするとともに、これら第１の現像剤攪拌部材と第２の
現像剤攪拌部材との間に、両端に現像剤の連絡通路を確
保する形状の仕切部材を設け、現像剤がループ状に循環
するように構成した現像ユニットにおいて、前記第２の
現像剤攪拌部材を、楕円板形状の搬送スクリュー部と、
羽根の外径が上記第１の現像剤攪拌部材へ現像剤を受け
渡す側の連絡通路に近づくにつれて全体としてテーパ状
に小さくなるテーパスクリュー部とからなる構成にし、
当該第２の現像剤攪拌部材を保持するケーシング内には
上記テーパスクリュー部の外径に沿って内径がテーパ状
に小さくなる筒状のガイド部材を配置する、という構成
を採っている。請求項２記載の発明では、請求項１記載
の構成において、前記第１の現像剤攪拌部材の現像剤搬
送速度を、前記第２の現像剤攪拌部材の現像剤搬送速度
より同等かそれ以上に設定する、という構成を採ってい
る。According to the present invention, a portion having a high compression ratio is provided in the circulating flow of the developer to increase the specific charge of the toner, and the developer having a sufficiently raised Q / M is formed in the circulating flow. It relies on the idea of re-incorporating it to get a rise in the overall specific charge of the developer. Based on this idea, according to the first aspect of the present invention, the developing sleeve for supplying and developing the toner on the surface of the photoreceptor, and agitating and transporting the developer in a direction extending in the axial direction of the developing sleeve in opposite directions. The first developer agitating member is provided near the developing sleeve, the second developer agitating member is provided farther from the developing sleeve, and the first developer agitating member and the second developer agitating member are provided near the developing sleeve. In the developing unit, a partition member having a shape for securing a communication passage for the developer is provided at both ends between the developer stirring member and the developer, and the developer is circulated in a loop. With an elliptical plate-shaped conveying screw part,
A taper screw portion which becomes smaller as a whole as the outer diameter of the blade approaches the communication passage on the side for delivering the developer to the first developer stirring member,
In the casing holding the second developer stirring member, a cylindrical guide member having an inner diameter tapered along the outer diameter of the tapered screw portion is disposed. According to a second aspect of the invention, in the configuration of the first aspect, the developer transport speed of the first developer stirring member is equal to or higher than the developer transport speed of the second developer stirring member. Configuration.
【０００６】[0006]
【実施例】以下、本発明の一実施例を図１乃至図５に基
づいて説明する。図１に示すように、感光体２に沿って
その表面上に現像用のトナーを供給する現像スリーブ４
が備えられ、この現像スリーブ４の上部には当該現像ス
リーブ４に供給された現像剤を一定の層厚にカットする
ドクターブレード５が軸線に沿って設けられている。ま
た、現像スリーブ４に沿って第１の現像剤攪拌部材６
と、第２の現像剤攪拌部材８とが並設されており、第２
の現像剤攪拌部材８の奥側には現像剤立上げ機構の要素
の一つである筒状のガイド部材１０が配置されている。
第１の現像剤攪拌部材６と第２の現像剤攪拌部材８との
間には、軸方向両端に現像剤の連絡通路１４，１６（図
４参照）を確保する形状の仕切部材１８が設けられてい
る。そして、上述の現像スリーブ４以下を主要部として
現像ユニットが構成されている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, a developing sleeve 4 for supplying toner for development along the photoreceptor 2 onto the surface thereof
A doctor blade 5 for cutting the developer supplied to the developing sleeve 4 into a certain layer thickness is provided along the axis on the upper portion of the developing sleeve 4. Further, the first developer stirring member 6 is arranged along the developing sleeve 4.
And a second developer stirring member 8 are provided side by side.
A cylindrical guide member 10, which is one of the elements of the developer rising mechanism, is disposed behind the developer stirring member 8 of the first embodiment.
Between the first developer agitating member 6 and the second developer agitating member 8, there are provided partition members 18 each having a shape for securing communication passages 14, 16 (see FIG. 4) for the developer at both axial ends. Have been. The developing unit is configured with the above-described developing sleeve 4 and below as main components.
【０００７】図１において、符号２０は帯電ローラ、２
２は転写ローラ、２４は除電針、２５はクリーニング装
置、２６はクリーニングブレード、２８はトナーリサイ
クルベルト、３０は透磁率測定センサをそれぞれ示す。
図１に基づいて作像系の基本的な動きについて説明す
る。まず、感光体２は図示しない除電部から照射される
除電光３２によって除電され、表面電位が０〜１５０Ｖ
の基準電位に平均化される。次に、感光体２は帯電ロー
ラ２０により帯電され、表面電位が−８５０Ｖ前後とな
る。そして、図示しない露光部より照射される光３４で
露光され、光３４が照射された部分（画像部分）は表面
電位が０〜２００Ｖとなる。現像スリーブ４には−６０
０Ｖ前後のバイアスがかけられているため、画像部分に
現像スリーブ４上のトナーが付着する。トナー像が形成
された感光体２は回転移動し、これに伴って、図示しな
い給紙部から用紙先端部と画像先端部とが転写ローラ２
２部位で一致するようなタイミングで用紙が送られる。
そして、転写ローラ２２部位で感光体２の表面のトナー
像が用紙へ転写される。転写後、用紙は図示しない定着
部へ送られ、熱と圧力でトナーが溶融して用紙に定着
し、コピーとして排出される。転写分離の際、用紙は除
電針２４で除電され、感光体２からの分離が助勢され
る。感光体２上に残った残留トナーは、クリーニングブ
レード２６により掻き落とされ、感光体２はトナーの無
い状態で再び次の作像工程へ移る。上記感光体２、帯電
ローラ２０、現像スリーブ４等で構成される現像ユニッ
ト、クリーニング装置２５等は、一体に形成された感光
体回りケース６０内に納められている（図５）。In FIG. 1, reference numeral 20 denotes a charging roller, 2
2 denotes a transfer roller, 24 denotes a static elimination needle, 25 denotes a cleaning device, 26 denotes a cleaning blade, 28 denotes a toner recycling belt, and 30 denotes a magnetic permeability measurement sensor.
The basic operation of the imaging system will be described with reference to FIG. First, the photoreceptor 2 is neutralized by static elimination light 32 emitted from a static elimination unit (not shown), and has a surface potential of 0 to 150 V.
Is averaged. Next, the photoconductor 2 is charged by the charging roller 20, and the surface potential becomes around -850V. Then, it is exposed to light 34 emitted from an exposure unit (not shown), and the portion (image portion) irradiated with the light 34 has a surface potential of 0 to 200V. -60 to the developing sleeve 4
Since a bias of about 0 V is applied, the toner on the developing sleeve 4 adheres to the image portion. The photoreceptor 2 on which the toner image has been formed is rotated, and accordingly, the leading end of the sheet and the leading end of the image are transferred from a feeding unit (not shown) to the transfer roller 2.
The paper is fed at such a timing that the two parts match.
Then, the toner image on the surface of the photoconductor 2 is transferred to the sheet at the transfer roller 22. After the transfer, the sheet is sent to a fixing unit (not shown), and the toner is melted by heat and pressure to be fixed on the sheet and discharged as a copy. At the time of transfer and separation, the sheet is discharged by the discharging needle 24, and separation from the photoconductor 2 is assisted. The residual toner remaining on the photoreceptor 2 is scraped off by the cleaning blade 26, and the photoreceptor 2 moves to the next image forming step again without toner. The developing unit including the photosensitive member 2, the charging roller 20, the developing sleeve 4, and the like, the cleaning device 25, and the like are housed in a photosensitive member surrounding case 60 integrally formed (FIG. 5).
【０００８】現像スリーブ４（アルミ円筒）の表面は、
無垢又は現像剤の搬送性を上げるために凹凸（例えばＶ
形溝）に形成されている。現像スリーブ４の内側には、
図３に示すように、円柱部材３６が設けられており、こ
の円柱部材３６には周方向に間隔をおいて５個の磁石Ｍ
1，Ｍ2，Ｍ3，Ｍ5，Ｍ6 が配設されている。これによっ
て、現像スリーブ４の円周上には磁力線Ｐ1，Ｐ2，
Ｐ3，Ｐ4，Ｐ5，Ｐ6 が存在し、一定の磁力分布が現れ
るようになっている。ドクターブレード５は、現像スリ
ーブ４に対して略法線方向に調整可能な構成となってい
る。現像スリーブ４の一端部（前端部又は手前側端部）
には、現像スリーブ４内に設けられた磁石Ｍの回転方向
を決める機能を有するとともにドクターブレード５を調
整可能に支持する支持部材３８が設けられており、他端
部には、現像スリーブ４の回転を受ける軸受の機能を有
するとともにドクターブレード５を調整可能に支持する
軸受が圧入された支持部材４０が設けられている（図
５）。ドクターブレード５が法線方向に調整可能に設け
られていることにより、ドクターブレード５の調整量
と、現像スリーブ４とドクターブレード５とのギャップ
Ｇは一対一で対応する。図３において、符号４２は入口
シール、４４は現像ケーシング部、６８は入口シールカ
バーをそれぞれ示す。The surface of the developing sleeve 4 (aluminum cylinder)
Solid or irregularities (e.g., V
Shaped groove). Inside the developing sleeve 4,
As shown in FIG. 3, a cylindrical member 36 is provided, and the cylindrical member 36 is provided with five magnets M at intervals in the circumferential direction.
1 , M 2 , M 3 , M 5 , M 6 are provided. As a result, the lines of magnetic force P 1 , P 2 ,
P 3 , P 4 , P 5 , P 6 are present, and a constant magnetic force distribution appears. The doctor blade 5 is configured to be adjustable in a substantially normal direction with respect to the developing sleeve 4. One end of the developing sleeve 4 (front end or front end)
Is provided with a support member 38 having a function of determining the rotation direction of the magnet M provided in the developing sleeve 4 and supporting the doctor blade 5 in an adjustable manner. A support member 40 having a bearing function for receiving rotation and press-fitted with a bearing for adjustingably supporting the doctor blade 5 is provided (FIG. 5). Since the doctor blade 5 is provided so as to be adjustable in the normal direction, the adjustment amount of the doctor blade 5 and the gap G between the developing sleeve 4 and the doctor blade 5 correspond one to one. In FIG. 3, reference numeral 42 denotes an inlet seal, 44 denotes a developing casing portion, and 68 denotes an inlet seal cover.
【０００９】第１の現像剤攪拌部材６は、図４及び図５
から明らかなように、それぞれ回転軸４６と、一部が切
り欠かれた楕円板形状の羽根５０とから成るスクリュー
形状に構成されている。一方、第２の現像剤攪拌部材８
は、回転軸４８と、楕円板形状の羽根５２とから成る基
本スクリュー形状の下、通常の搬送スクリュー部５３
と、羽根の外径が第１の現像剤攪拌部材６へ現像剤を受
け渡す側の連絡通路１６に近づくにつれて全体としてテ
ーパ状に小さくなるテーパスクリュー部５５とからなる
構成を有している。そして、テーパスクリュー部５５に
は、テーパスクリュー部５５の外径に沿って内径がテー
パ状に小さくなる筒状ガイド部材１０が嵌挿されてい
る。ガイド部材１０の外径は仕切部材１８とケーシング
側壁との間にフィットする大きさに設定されている。ま
た、第１の現像剤攪拌部材６は現像剤を手前方向（矢印
Ｆ方向）に、第２の現像剤攪拌部材８は現像剤を奥行方
向（矢印Ｂ方向）に攪拌しながら搬送するように構成・
設定されている。第１の現像剤攪拌部材６と第２の現像
剤攪拌部材８で攪拌・搬送される現像剤は、仕切部材１
８によって確保された連絡通路１４，１６においてそれ
ぞれ相手側に入り込み、これによって現像剤はループ状
に循環する。現像スリーブ４に供給された余分な現像剤
は第１の現像剤攪拌部材６で回収され、再び循環流に乗
せられる。現像剤はキャリアと呼ばれる小さな鉄球とト
ナーよりなる二成分構成である。現像剤中のトナー濃度
を透磁率測定センサ３０で検出し、トナーが不足してい
る場合には、検出信号に基づいてトナー補給部３１（図
４、但し、その他の図においては省略している。）より
現像ユニット内へ、具体的には第２の現像剤攪拌部材８
の端部へトナーが供給されるようになっている。図４に
おいて、符号３３は多数の穴が形成された補給用仕切
板、符号７０，７２，７４は回転伝達用の歯車をそれぞ
れ示す。The first developer stirring member 6 is shown in FIGS.
As is clear from FIG. 3, each is formed in a screw shape comprising a rotating shaft 46 and an elliptical plate-shaped blade 50 partially cut away. On the other hand, the second developer stirring member 8
Is an ordinary conveying screw 53 under a basic screw shape composed of a rotating shaft 48 and an elliptical blade 52.
And a tapered screw portion 55 that is tapered as a whole as the outer diameter of the blade approaches the communication passage 16 on the side that transfers the developer to the first developer stirring member 6. The cylindrical guide member 10 whose inner diameter is tapered along the outer diameter of the tapered screw portion 55 is fitted into the tapered screw portion 55. The outer diameter of the guide member 10 is set to a size that fits between the partition member 18 and the casing side wall. Further, the first developer stirring member 6 conveys the developer in the front direction (arrow F direction) and the second developer stirring member 8 conveys the developer in the depth direction (arrow B direction). Constitution·
Is set. The developer stirred and conveyed by the first developer stirring member 6 and the second developer stirring member 8 is separated from the partition member 1.
In the communication paths 14 and 16 secured by 8, each enters the other side, whereby the developer circulates in a loop. Excess developer supplied to the developing sleeve 4 is collected by the first developer stirring member 6, and is returned to the circulation flow. The developer has a two-component structure including a small iron ball called a carrier and toner. The toner concentration in the developer is detected by the magnetic permeability measurement sensor 30, and when the toner is insufficient, the toner supply unit 31 (FIG. 4, but omitted in other drawings) based on the detection signal. .) Into the developing unit, specifically, the second developer stirring member 8.
The toner is supplied to the end of. In FIG. 4, reference numeral 33 denotes a supply partition plate having a large number of holes, and reference numerals 70, 72, and 74 denote rotation transmitting gears.
【００１０】また、クリーニングブレード２６で掻き落
とされてクリーニング装置２５に回収された残留トナー
は、図示しないトナー搬送コイルで奥側より手前側へ搬
送され、リサイクルトナー搬送部５４へ送られる。リサ
イクルトナー搬送部５４は、図１及び図５に示すよう
に、駆動軸５６と、従動軸５８及びこれらの軸間に掛け
られた、送り羽根２８ａを有するトナーリサイクルベル
ト２８等から構成されており、奥側から送られてきたト
ナーは、トナーリサイクルベルト２８によって第２の現
像剤攪拌部材８の手前側端部へ送られ、トナーがリサイ
クルされる仕組みになっている。リサイクルトナー搬送
部５４も感光体回りケース６０と一体化されており、こ
れにより別体とした時の接合部でのトナー漏れの心配が
なく、また、これを防止するためのスポンジ部材の追加
等を行わなくてよい。また、一体化されているので、組
付性も向上する。The residual toner scraped off by the cleaning blade 26 and collected by the cleaning device 25 is conveyed from the back side to the front side by a toner conveying coil (not shown), and is sent to the recycled toner conveying section 54. As shown in FIGS. 1 and 5, the recycled toner transport section 54 includes a driving shaft 56, a driven shaft 58, and a toner recycling belt 28 having a feed blade 28a suspended between these shafts. The toner sent from the rear side is sent to the front end of the second developer stirring member 8 by the toner recycling belt 28, so that the toner is recycled. The recycled toner conveying section 54 is also integrated with the photoreceptor surrounding case 60, so that there is no risk of toner leakage at the joint when the separated toner conveying section 54 is separated, and a sponge member is added to prevent this. Need not be performed. In addition, since they are integrated, assemblability is also improved.
【００１１】次に、ガイド部材１０等によるトナー比電
荷の立ち上げ動作について説明する。第２の現像剤攪拌
部材８において、楕円板形状の羽根を有する搬送スクリ
ュー部５３で攪拌された現像剤は、テーパスクリュー部
５５とガイド部材１０との間を搬送されていく。この
時、現像剤は連絡通路１６側へ行くにつれて、テーパ形
状の特性によって密度の高い状態に圧縮されるので、こ
の高圧縮による摩擦によってキャリアが帯電し、キャリ
アに付着しているトナーのトナー比電荷（Ｑ／Ｍ）が上
昇する。このＱ／Ｍが十分に立ち上がった現像剤が第２
の現像剤攪拌部材８より連絡通路１６を介して第１の現
像剤攪拌部材６へ送られ、現像スリーブ４により感光体
２へ現像が行われる。実験の結果、地肌汚れの発生を抑
制できることが確認された。なお、この実施例において
は、図４に示すように、ガイド部材１０の奥側端部に径
大の空間部５７が形成されているとともに当該空間部５
７には径大の羽根５９が収容されており、連絡通路１６
における第１の現像剤攪拌部材６への現像剤の受け渡し
が円滑にできるようになっている。テーパスクリュー部
５５等のいわゆるトナー比電荷立上げ機構は、第２の現
像剤攪拌部材８の任意の位置に配置することができる
が、本実施例のように、Ｑ／Ｍが立ち上がっている現像
剤を直ちに、無駄なく正規の現像ルートへ移行させる観
点から、第１の現像剤攪拌部材６へ現像剤の受け渡しが
行われる連絡通路１６側へ配置して、最短距離供給の形
態とするのが望ましい。また、このトナー比電荷立上げ
機構では、ガイド部材１０により現像剤の搬送速度が増
すので、ガイド部材１０の中で現像剤詰まりをしないよ
うに、第１の現像剤攪拌部材６の現像剤搬送速度は第２
の現像剤攪拌部材８の現像剤搬送速度と同等かそれ以上
に設定されている。Next, the operation of raising the toner specific charge by the guide member 10 and the like will be described. In the second developer stirring member 8, the developer stirred by the transfer screw portion 53 having elliptical blades is transferred between the tapered screw portion 55 and the guide member 10. At this time, the developer is compressed to a high density state by the characteristics of the taper shape as it goes to the communication passage 16 side, so that the carrier is charged by the friction due to the high compression, and the toner ratio of the toner attached to the carrier is reduced. The charge (Q / M) increases. The developer whose Q / M has sufficiently risen is the second developer.
The developer is supplied from the developer stirring member 8 to the first developer stirring member 6 via the communication passage 16, and is developed on the photoconductor 2 by the developing sleeve 4. As a result of the experiment, it was confirmed that the generation of the background stain could be suppressed. In this embodiment, as shown in FIG. 4, a large-diameter space portion 57 is formed at the rear end of the guide member 10 and the space portion 5
A large-diameter blade 59 is housed in the communication passage 16.
The developer can be smoothly delivered to the first developer stirring member 6 in the above. The so-called toner specific charge raising mechanism such as the tapered screw portion 55 can be arranged at an arbitrary position of the second developer stirring member 8, but as in the present embodiment, the development in which the Q / M rises. From the viewpoint of immediately transferring the developer to the regular developing route without waste, it is preferable to dispose the developer on the side of the communication passage 16 where the developer is delivered to the first developer stirring member 6 so as to supply the shortest distance. desirable. Further, in this toner specific charge rising mechanism, since the transport speed of the developer is increased by the guide member 10, the developer transport of the first developer stirring member 6 is performed so that the developer is not clogged in the guide member 10. Speed is second
Is set to be equal to or higher than the developer conveying speed of the developer stirring member 8.
【００１２】[0012]
【発明の効果】請求項１記載の発明によれば、第２の現
像剤攪拌部材にテーパスクリュー部を設けるとともにこ
れをテーパ状の内面を有するガイド部材で覆う構成とし
たので、第２の現像剤攪拌部材の通常部分で攪拌された
現像剤がテーパスクリュー部で高密度に圧縮されてキャ
リアが摩擦帯電し、現像剤はトナーの比電荷を十分に立
ち上げられた状態で第１の現像剤攪拌部材へ送られる。
これによって、感光体面上の地肌部に当たる所（本来ト
ナーが付着してはならない所）にトナーが付着すること
が抑制され、画像上のいわゆる地肌汚れの抑制によって
画像品質の向上を図ることができる。請求項２記載の発
明によれば、第１の現像剤攪拌部材の現像剤搬送速度を
第２の現像剤攪拌部材の現像剤搬送速度と同等かそれ以
上に設定したので、テーパスクリュー部における搬送速
度増加による現像剤詰まりを防止して円滑な現像剤循環
流を形成することができる。According to the first aspect of the present invention, the second developer agitating member is provided with the tapered screw portion and is covered with the guide member having the tapered inner surface. The developer agitated in the normal portion of the developer agitating member is compressed at a high density by the tapered screw portion and the carrier is frictionally charged, and the developer is charged in a state where the specific charge of the toner is sufficiently raised. It is sent to the stirring member.
As a result, it is possible to suppress the toner from adhering to the portion of the photoreceptor surface that hits the background portion (the portion where the toner should not originally adhere), thereby improving the image quality by suppressing the so-called background stain on the image. . According to the second aspect of the present invention, the developer transport speed of the first developer stirring member is set to be equal to or higher than the developer transport speed of the second developer stirring member. It is possible to prevent developer clogging due to an increase in speed and to form a smooth developer circulation flow.
【図１】本発明の一実施例を示す現像ユニットの概要断
面図である。FIG. 1 is a schematic sectional view of a developing unit showing one embodiment of the present invention.
【図２】ケーシングの上蓋をした状態の現像ユニットの
概要断面図である。FIG. 2 is a schematic cross-sectional view of a developing unit in a state in which a casing has a top cover.
【図３】現像スリーブの磁力分布を示す要部断面図であ
る。FIG. 3 is a sectional view of a main part showing a magnetic force distribution of a developing sleeve.
【図４】上面側からみた一部省略の断面図である。FIG. 4 is a partially omitted cross-sectional view as viewed from the upper surface side.
【図５】一部省略の斜視図である。FIG. 5 is a partially omitted perspective view.
２ 感光体 ４ 現像スリーブ ６ 第１の現像剤攪拌部材 ８ 第２の現像剤攪拌部材 １０ ガイド部材 １４，１６ 連絡通路 １８ 仕切部材 ５３ 搬送スクリュー部 ５５ テーパスクリュー部 Reference Signs List 2 photoconductor 4 developing sleeve 6 first developer stirring member 8 second developer stirring member 10 guide member 14, 16 communication passage 18 partitioning member 53 transport screw 55 taper screw
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平４−204574（ＪＰ，Ａ) 特開 平４−254878（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G03G 15/08 G03G 15/09 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-204574 (JP, A) JP-A-4-254878 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) G03G 15/08 G03G 15/09
Claims (2)
めの現像スリーブと、この現像スリーブの軸線方向に沿
って延び前後反対方向に現像剤を攪拌・搬送する二つの
現像剤攪拌部材を設け、現像スリーブに近い方を第１の
現像剤攪拌部材、遠い方を第２の現像剤攪拌部材とする
とともに、これら第１の現像剤攪拌部材と第２の現像剤
攪拌部材との間に、両端に現像剤の連絡通路を確保する
形状の仕切部材を設け、現像剤がループ状に循環するよ
うに構成した現像ユニットにおいて、 前記第２の現像剤攪拌部材を、楕円板形状の搬送スクリ
ュー部と、羽根の外径が上記第１の現像剤攪拌部材へ現
像剤を受け渡す側の連絡通路に近づくにつれて全体とし
てテーパ状に小さくなるテーパスクリュー部とからなる
構成にし、当該第２の現像剤攪拌部材を保持するケーシ
ング内には上記テーパスクリュー部の外径に沿って内径
がテーパ状に小さくなる筒状のガイド部材を配置したこ
とを特徴とする現像ユニット。A developing sleeve for supplying toner to the surface of the photoreceptor to develop the toner; and two developer stirring members extending along the axial direction of the developing sleeve and stirring and transporting the developer in opposite directions. The first developer agitating member is closer to the developing sleeve, the second developer agitating member is farther from the developing sleeve, and is located between the first developer agitating member and the second developer agitating member. A developing member provided at both ends thereof with a partition member having a shape for securing a communication passage for the developer, wherein the developer is circulated in a loop. And a tapered screw portion whose overall diameter becomes smaller in a tapered manner as the outer diameter of the blade approaches the communication passage on the side for transferring the developer to the first developer stirring member. Agent stirring section A developing unit, wherein a cylindrical guide member having an inner diameter tapered along the outer diameter of the tapered screw portion is disposed in a casing holding the material.
度が、前記第２の現像剤攪拌部材の現像剤搬送速度より
同等かそれ以上に設定されていることを特徴とする請求
項１記載の現像ユニット。2. The developer conveying speed of the first developer stirring member is set to be equal to or higher than the developer conveying speed of the second developer stirring member. 2. The developing unit according to 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22782095A JP3323369B2 (en) | 1995-09-05 | 1995-09-05 | Development unit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22782095A JP3323369B2 (en) | 1995-09-05 | 1995-09-05 | Development unit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0973219A JPH0973219A (en) | 1997-03-18 |
| JP3323369B2 true JP3323369B2 (en) | 2002-09-09 |
Family
ID=16866895
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22782095A Expired - Fee Related JP3323369B2 (en) | 1995-09-05 | 1995-09-05 | Development unit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3323369B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6763214B2 (en) | 2001-08-07 | 2004-07-13 | Ricoh Company, Ltd. | Developing device and method for performing effective charging and mixing of developer and image forming apparatus using the developing device |
| JP4185727B2 (en) * | 2002-07-11 | 2008-11-26 | 株式会社リコー | Image forming apparatus |
| JP5303289B2 (en) * | 2009-01-29 | 2013-10-02 | 京セラドキュメントソリューションズ株式会社 | Toner transport device, cleaning device, and image forming apparatus |
-
1995
- 1995-09-05 JP JP22782095A patent/JP3323369B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0973219A (en) | 1997-03-18 |
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