JP4945034B2 - Developing device, process cartridge, and image forming apparatus - Google Patents

Description

【００２４】

【００２５】

【００２６】
（１）第１の実施の形態…請求項１に対応
第１の実施の形態を説明する。
通常、本プロセスカートリッジ（現像装置）ＧＳを水平状態にし、現像剤プリセットシール３１を引き抜くと、現像剤プリセットケース３０内の現像剤はすべて現像剤収容室７内に移動する。このとき、プリセットケース内にセットされているトナー濃度が５ｗｔ％で、現像剤量は６４ｇである。
図２（Ａ）〜（Ｃ）に示すように、現像剤プリセットケース３０と現像剤収容室７との間を仕切るための、「現像剤滞留高さ規制手段」である現像剤収容室規制シール３２を配置する。このようにすれば、プロセスカートリッジが傾斜していても、現像剤プリセットシール３１を開封作業後に、現像装置ＧＳの傾斜の影響で、現像剤３ａが現像剤プリセットケース３０内へ落下することによる、現像剤収容室７内における現像剤の高さの大きな変化を規制することができる（図２（Ｂ））。
【００２７】
即ち、現像剤プリセットシール３１を引き抜く以前は図2（Ａ）に示す状態であり、現像剤３ａは該シール３１の上方に収納されている。次いで、図２（Ｂ）に示すように、現像剤プリセットシール３１を半分ほど引き抜くと、収納された現像剤３ａの半分ほどが下方に落下し、更に該シール３１を引き抜くと残りの現像剤３ａが落下する。従って、図２（Ｃ）に示すように、現像装置ＧＳが傾斜していた場合であっても、現像剤３ａは現像剤収容室７にほぼ均一に落下する。
また、具体的には図３（Ａ），（Ｂ）に示すように、現像剤プリセットケース３０の内部は６つに仕切られているので、現像剤プリセットケース３０内での現像剤３ａの移動は規制され、それぞれの仕切りないの現像剤３ａは、ほぼ真下の現像剤収容室７に落下する。
【００２８】
（２）第２の実施の形態…請求項２に対応
第２の実施の形態を説明する。
現像剤３ａを現像剤収容室７に落下させた後に（図１参照）、例えば現像装置ＧＳを傾斜させると、現像剤３ａも斜めになってしまい、従来技術で説明したように、画像濃度不足やひどい場合にはキャリア付着のような不具合を起こす場合がある。本実施の形態は、かかる事態を防止する。
【００２９】
この防止手段としては、図４に示すように、プリセットケース３０の下面側と現像剤収容室７の上部側との間に、現像剤収容室７の空間部を規制する空間規制手段としての現像剤プリセットシール３２を配置すればよい。
即ち、図５（Ａ），（Ｂ），（Ｃ）に示すように、ロール状に巻いた現像剤収容室規制シール３２の先端部と、現像剤プリセットシール３１の折り返し部とを糸状部材３４で連結し、現像剤プリセットシール３１の引き抜き動作と同時に現像剤収容室７の上部側に現像剤収容室規制シール３２が介在するようにする。
このようにすれば、現像装置を画像形成装置にセットする際に、シール開封と現像剤滞留高さ規制とを、ワンアクション（一回の動作）で終了させることができる。また、現像装置ＧＳあるいは画像形成装置（図示省略）を傾斜させた場合であっても、現像剤３ａが斜めになるのを防止することができ、従って、画像濃度不足等の不具合を防止できる。
また、現像剤収容室規制シール３２は現像剤プリセットシール３１の引き抜き側と反対側に配置しておくことが望ましい。このようにすれば、ユーザが該シール３１の引き抜き時に、引き抜き側を上げて操作することができ、操作性が良くなる。
【００３０】
（３）第３の実施の形態…請求項３に対応第３の実施の形態を説明する。前記第２の実施の形態では、現像剤プリセットシール３１と現像剤収容室規制シール３２とを別体に構成していた（図５における現像剤プリセットケース３１と現像剤プリセットシール３２）。これに対し本実施の形態は、現像剤プリセットケースと現像剤収容室規制シールとを一体に構成した場合である。図６（Ａ）に示すように、現像剤プリセットケース３０の長手方向周囲に、ベルト状の現像剤プリセットシール３５を回転自在に巻回配置する。現像剤プリセットケース３５の一部に現像剤落下口３６を形成する。
【００３１】
そして、図６（Ｂ）に示すように、現像剤プリセットシール３５を回転させることにより、現像剤３ａを現像剤収容室７に落下させると同時に、現像剤収容室７の上部側を規制することができる（図４参照）。なお、現像剤プリセットケース３０と現像剤収容室７の間は、該ケースと現像剤収容室の対向部分がガード（位置決め）の役割をするので、現像剤プリセットシール３５がずれることはない。
【００３２】
（４）第４の実施の形態…請求項４に対応
第４の実施の形態を説明する。
図７に画像形成装置にセットする本発明の現像装置（プロセスカ−トリッジ）の要部構成を示す。
図７において、符号２１は帯電手段、２２は現像手段（図１の現像部Ｇ）、２３はクリーニング手段である。
本実施の形態においては、感光体ドラム１、帯電装置手段２１、現像手段２２及びクリ−ニング手段２３等の構成要素のうち、複数のものをプロセスカ−トリッジとして一体に結合して構成し、このプロセスカ−トリッジを複写機やプリンタ−等の画像形成装置本体に対して着脱可能に構成する。
【００３３】
かかるプロセスカ−トリッジをセットした画像形成装置は、感光体ドラム１が所定の周速度で回転駆動される。感光体ドラム１は回転過程において、帯電手段２１によりその周面に正または負の所定電位の均一帯電を受け、次いで、スリット露光やレ−ザ−ビ−ム走査露光等の像露光手段（図示省略）からの画像露光光を受け、感光体ドラム１の周面に静電潜像が順次形成され、形成された静電潜像は、現像手段２２によりトナ−現像される。現像されたトナ−像は、給紙部（図示省略）から感光体ドラム１と転写手段（図示省略）との間に感光体ドラム１の回転と同期されて給送された転写材に、転写手段により順次転写されていく。
【００３４】
像転写を受けた転写材は感光体ドラム面から分離されて像定着手段（図示省略）へ導入されて像定着され、複写物（コピ−）として装置外へプリントアウトされる。像転写後の感光体ドラム１の表面は、クリ−ニング手段２３によって転写残りトナ−の除去を受けて清浄面化され、更に除電された後、繰り返し画像形成に使用される。
【００３５】
（５）第５の実施の形態…請求項５に対応
第５の実施の形態を説明する。
本実施の形態は画像の解像度を向上させる場合である。現像剤の重量平均径が４〜１５μｍであれば、得られる画像の解像度が向上する。
重量平均径の測定方法は、以下の手順にて行う。
まず、電解水溶液１００〜１５０ｍｌ中に分散剤として界面活性剤（好ましくはアルキルベンゼンスルフォン酸塩）を０．１〜５ｍｌ加える。ここで、電解液とは１級塩化ナトリウムを用いて約１％ＮａＣｌ水溶液を調製したもので、例えばＩＳＯＴＯＮ−ＩＩ（コールター社製）が使用できる。
【００３６】
ここで、更に測定試料を２〜２０ｍｇ加える。試料を懸濁した電解液は、超音波分散器で約１〜３分間分散処理を行ない、前記測定装置により、アパーチャーとして１００μｍアパーチャーを用いて、トナー粒子又はトナーの体積、個数を測定して、体積分布と個数分布を算出する。得られた分布から、トナーの重量平均粒径（Ｄ４）、個数平均粒径を求めることができる。
【００３７】
チャンネルとしては、2.00〜2.52μｍ未満；2.52〜3.17μｍ未満；3.17〜4.00μｍ未満；4.00〜5.04μｍ未満；5.04〜6.35μｍ未満；6.35〜8.00μｍ未満；8.00〜10.08μｍ未満；10.08〜12.70μｍ未満；12.70〜16.00μｍ未満；16.00〜20.20μｍ未満；20.20〜25.40μｍ未満；25.40〜32.00μｍ未満；32.00〜40.30μｍ未満の１３チャンネルを使用し、粒径2.00μｍ以上乃至40.30μｍ未満の粒子を対象とする。
【００３８】
「現像剤を構成する材料」
一成分、二成分いずれにも通じる記載とする。トナーを構成する結着樹脂や着色剤などの材料を挙げる。
トナー全体に占める割合は、結着樹脂が７５％〜９３％、着色剤が３％〜１０％、離型剤が３％〜８％、その他の成分は１％〜７％である。
使用される結着樹脂としては、例えば、ポリスチレン、ポリ−ｐ−クロルスチレン、ポリビニルトルエンの如きスチレン及びその置換体の単重合体；スチレン−ｐ−クロルスチレン共重合体、スチレン−ビニルトルエン共重合体、スチレン−ビニルナフタリン共重合体、スチレン−アクリル酸エステル共重合体、スチレン−メタクリル酸エステル共重合体、スチレン−α−クロルメタクリル酸メチル共重合体、スチレン−アクリロニトリル共重合体、スチレン−ビニルメチルエーテル共重合体、スチレン−ビニルエチルエーテル共重合体、スチレン−ビニルメチルケトンなどが挙げられる。
【００３９】
着色剤としては、従来より知られている無機又は有機の染料／顔料が使用可能であり、例えば、カーボンブラック、アニリンブラック、アセチレンブラック、ナフトールイエロー、ハンザイエロー、ローダムンレーキ、アリザリンレーキ、ベンガラ、フタロシアニンブルー、インダスレンブルーがあげられる。
【００４０】
必要に応じて着色剤として磁性材料を用いることも可能である。
磁性材料としては、マグネタイト、γ−酸化鉄、フェライト鉄、過剰型フェライトの如き酸化鉄；鉄、コバルト、ニッケルの如き磁性金属；酸化鉄又は磁性金属と、コバルト、スズ、チタン、銅、鉛、亜鉛、マグネシウム、マンガン、アルミニウム、珪素の如き金属との複合金属酸化物合金又は、混合物が挙げられる。
これら磁性粒子は、平均粒径が0.05乃至1.0μｍの範囲内であることが好ましく、より好ましくは0.1乃至0.6μｍの範囲内、さらに好ましくは、0.1乃至0.4μｍの範囲内であることが良い。
これらの磁性粒子は、窒素吸着法によるＢＥＴ比表面積が好ましくは１乃至２０ｍ² ／ｇの範囲内、特に２．５乃至１２ｍ² ／ｇの範囲内であることが良く、更にモース硬度が５〜７の範囲内であることが良い。
【００４１】
磁性粒子の形状としては、８面体、６面体、球形、針状、鱗片状があるが、８面体、６面体、球形の異方性の少ないものが好ましい。"
磁性トナーとして用いる場合、磁性材料を含有する磁性トナー粒子は、結着樹脂１００質量部に対し１０〜１５０質量部、好ましくは２０〜１２０質量部磁性材料を含有することが良い。
【００４２】
本発明のトナーには、実質的な悪影響を与えない範囲内で添加剤を少量用いることができる。
この添加剤としては、例えばテフロン粉末、ステアリン酸亜鉛粉末、ポリフッ化ビニリデン粉末の如き滑剤粉末；酸化セリウム粉末、炭化硅素粉末、チタン酸ストロンチウム粉末の如き研磨剤；例えば酸化チタン粉末、酸化アルミニウム粉末の如き流動性付与剤又はケーキング防止剤；例えばカーボンブラック粉末、酸化亜鉛粉末、酸化スズ粉末の如き導電性付与剤；及び逆極性の有機微粒子又は無機微粒子が挙げられる。
【００４３】
また、定着性などを改善するために離型剤を添加することもできる。
離型剤としては、パラフィンワックス及びその誘導体、マイクロクリスタリンワックス及びその誘導体、フィッシャートロプシュワックス及びその誘導体、ポリオレフィンワックス及びその誘導体、カルナバワックス及びその誘導体が挙げられる。誘導体は、酸化物、ビニル系モノマーとのブロック共重合体、ビニル系モノマーのグラフト変性物を含む。
その他、アルコール、脂肪酸、酸アミド、エステル、ケトン、硬化ヒマシ油及びその誘導体、植物系ワックス、動物性ワックス、鉱物系ワックス、ペトロラクタムも利用できる。
【００４４】
そして、トナーを負荷電性に制御する荷電制御剤としては、例えば有機金属錯体、キレート化合物が有効であり、モノアゾ金属錯体、アセチルアセトン金属錯体、芳香族ハイドロキシカルボン酸系金属錯体、芳香族ダイカルボン酸系金属錯体があげられる。他には、芳香族ハイドロキシカルボン酸、芳香族モノ及びポリカルボン酸及びその金属塩、その無水物、そのエステル類、ビスフェノールの如きフェノール誘導体類がある。
【００４５】
トナーを正荷電性に制御する荷電制御剤としては、ニグロシン及び脂肪酸金属塩による変性物；トリブチルベンジルアンモニウム−１−ヒドロキシ−４−ナフトスルフォン酸塩、テトラブチルアンモニウムテトラフルオロボレートの如き四級アンモニウム塩、及びこれらの類似体であるホスホニウム塩の如きオニウム塩及びこれらのレーキ顔料、トリフェニルメタン染料及びこれらのレーキ顔料（レーキ化剤としては、燐タングステン酸、燐モリブデン酸、燐タングステンモリブデン酸、タンニン酸、ラウリン酸、没食子酸、フェリシアン化物、フェロシアン化物）が挙げられる。
この微粒子状の荷電制御剤の個数平均粒径は好ましくは、４μｍ以下、より好ましくは、３μｍ以下が良い。
【００４６】
これらの荷電制御剤をトナー粒子中に内添する場合には、トナー粒子は、結着樹脂１００質量部に対して好ましくは、０．１〜２０質量部、より好ましくは、０．２〜１０質量部含有することが良い。
これらのトナーは、必要に応じて、一般に広く使用されているトナー用の添加剤、例えばコロイダルシリカのような流動化剤、酸化チタン、酸化アルミニウム等の金属酸化物や、炭化ケイ素等の研磨剤、脂肪酸金属塩などの滑剤等を含有させてもよい。
【００４７】
無機微粉体はトナーに対して０．１〜２重量％使用されるのが好ましい。０．１重量％未満では、トナー凝集を改善する効果が乏しくなり、２重量％を超える場合は、細線間のトナー飛び散り，機内の汚染，感光体の傷や摩耗等の問題が生じやすい傾向がある。
添加剤をトナーに混合する方法としては、従来公知の方法でよく、ヘンシェルミキサー、スピードニーダー等の装置により混合することができる。
トナー混練・冷却後のトナー粉の製造方法としては、従来公知の方法でよく、例えば混練・冷却した後、これをジェットミルで粉砕し、分級して得られる。
【００４８】
このようにして製造される静電荷像現像用トナーは、乾式一成分現像及び乾式二成分現像剤として使用できる。
二成分現像剤として用いる場合、トナーとキャリアとの混合割合は、一般にキャリア１００重量部に対しトナー０．５〜６．０重量部程度が適当である。
乾式二成分現像剤として使用する場合、キャリア並びに本発明のトナーの使用量としては、トナー粒子がキャリア粒子のキャリア表面に付着して、その表面積の３０〜９０％を占める程度に両粒子を混合するのが好ましい。
【００４９】
本発明に用いる現像剤を構成するキャリアの核体粒子としては、従来より公知のものでよく例えば鉄、コバルト、ニッケル等の強磁性金属；マグネタイト、ヘマタイト、フェライトなどの合金や化合物；前記強磁性体微粒子と樹脂との複合体等が挙げられる。
これら本発明で用いられるキャリアはより耐久性を長くする目的で、表面を樹脂で被覆することが好ましい。
【００５０】
被覆層を形成する樹脂としては、例えばポリエチレン、ポリプロピレン、塩素化ポリエチレン、クロロスルホン化ポリエチレン等のポリオレフィン系樹脂；ポリスチレン、アクリル（例えばポリメチルメタクリレート）、ポリアクリロニトリル、ポリビニルアセテート、ポリビニルアルコール、ポリビニルブチラール、ポリ塩化ビニル、ポリビニルカルバゾール、ポリビニルエーテル、ポリビリケトン等のポリビニル及びポリビニリデン系樹脂；塩化ビニル−酢酸ビニル共重合体；；オルガノシロキサン結合からなるシリコーン樹脂またはその変成品（例えばアルキッド樹脂、ポリエステル樹脂、エポキシ樹脂、ポリウレタン等による変成品）；ポリテトラフルオロエチレン、ポリ弗化ビニル、ポリ弗化ビニリデン、ポリクロロトリフルオロエチレン等の弗素樹脂；ポリアミド；ポリエステル；ポリウレタン；ポリカーボネート；尿素−ホルムアルデヒド樹脂等のアミノ樹脂；エポキシ樹脂等が挙げられる。
中でもトナースペントを防止する点で好ましいのはシリコーン樹脂またはその変成品、弗素樹脂、特にシリコーン樹脂またはその変成品である。
【００５１】
被覆層の形成法としては、従来と同様、キャリア核体粒子の表面に被覆層形成液を噴霧法、浸漬法等の手段で塗布すればよい。
被覆層の厚さは０．１〜２０μmが好ましい。
具体例
二成分現像剤としての製造例

上記組成の混合物を、溶融混練し、その後、粉砕、分級した。
【００５２】
さらに、母体着色粒子１００重量部に対して、疎水性シリカ０．３重量部を混合し、平均粒径９．０μｍのトナーを得た。
また、湿式法により作成したマグネタイト１００重量部に対してポリビニルアルコール２重量部、水６０重量部をボールミルに入れ１２時間混合してマグネタイトのスラリーを調整した。
このスラリーをスプレードライヤーにて噴霧造粒し、球形粒子とした。
この粒子を窒素雰囲気中で１０００℃の温度で３時間焼成後冷却し核体粒子１を得た。

上記混合物をホモミキサーで２０分間分散し、被覆層形成液１を調整した。
この被覆層形成液を流動床型コーティング装置を用いて核体粒子１を１０００重量部の表面にコーティングして、シリコーン樹脂被覆キャリアを得た。
上記磁性キャリアを97.5重量部に対し、トナー2.5重量部の割合で混合し、二成分現像剤を作成した。
【００５３】
（６）第６の実施の形態…請求項６に対応
第６の実施の形態を説明する。
図８において、現像時、現像スリーブ４には、電源２６により現像バイアスとして、直流電圧に交流電圧を重畳した振動バイアス電圧が印加される。背景部電位と画像部電位は、上記振動バイアス電位の最大値と最小値の間に位置している。これによって現像手段２４に向きが交互に変化する交互電界が形成される。この交互電界中で現像剤のトナーとキャリアが激しく振動し、トナーが現像スリーブ４およびキャリアへの静電的拘束力を振り切って感光体ドラム１に飛翔し、感光体ドラム１の潜像に対応して付着する。
【００５４】
振動バイアス電圧の最大値と最小値の差(ピーク間電圧)は、0.5〜５ｋＶが好ましく、周波数は１〜１０ｋＨｚが好ましい。振動バイアス電圧の波形は、矩形波、サイン波、三角波等が使用できる。振動バイアスの直流電圧成分は、上記したように背景部電位と画像部電位の間の値であるが、画像部電位よりも背景部電位に近い値である方が、背景部電位領域へのかぶりトナーの付着を防止する上で好ましい。
【００５５】
振動バイアス電圧の波形が矩形波の場合、デューティ比を50％以下とすることが望ましい。ここでデューティ比とは、振動バイアスの1周期中でトナーが感光体に向かおうとする時間の割合である。このようにすることにより、トナーが感光体に向かおうとするピーク値とバイアスの時間平均値との差を大きくすることができるので、トナーの運動がさらに活発化し、トナーが潜像面の電位分布に忠実に付着してざらつき感や解像力を向上させることができる。またトナーとは逆極性の電荷を有するキャリアが感光体に向かおうとするピーク値とバイアスの時間平均値との差を小さくすることができるので、キャリアの運動を沈静化し、潜像の背景部にキャリアが付着する確率を大幅に低減することができる。
【００５６】
【発明の効果】
以上説明したように本発明によれば、以下の効果を発揮することができる。請求項１によれば、現像剤収容室に落下した現像剤の高さが規制され、初期セットアップ操作時に現像装置が衝撃や誤操作等を受けても現像剤が偏ることがなくなり、地汚れや画像濃度低下のない画像が得られる。また、現像装置を画像形成装置にセットする際に、シール開封と現像剤滞留高さ規制とを、ワンアクション（一回の動作）で終了させることができる。
【００５７】
請求項２によれば、例えば、現像剤プリセットケースの外周部に円環状の現像剤プリセットシールを配置することにより、現像剤の封止機能と現像剤滞留高さ規制機能とを一つの部材で達成することができるので、コストダウンおよび自然環境の保護に寄与することができる。請求項３によれば、画像形成装置本体にセットして使用する現像剤およびトナーを備えた現像装置に、感光体と帯電手段とクリ−ニング手段の内の少なくとも何れか１つを一体に構成するので、部品点数が減少し、ユーザの操作性を向上させることができる。
【００５８】
請求項４によれば、現像剤の重量平均径が４〜１５μｍなので、得られる画像の解像度が向上する。請求項５によれば、現像装置によって像担持体上の潜像を現像する際に、直流電圧に交流電圧を重畳した振動バイアス電圧が印加するので、ざらつきのない高精細な画像が得られる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態の側断面図である。
【図２】同第１の実施の形態の作用を説明する図であって、（Ａ）は現像剤プリセットケースを斜めにした状態、（Ｂ）は現像剤プリセットシールを半分引き抜いた状態、（Ｃ）は現像剤プリセットシールを全て引き抜いた状態である。
【図３】同第１の実施の形態において、（Ａ）は現像剤プリセットケースの内部を６つに仕切った側断面図、（Ｂ）は現像剤プリセットシールを半分引き抜いた状態を示す側断面図である。
【図４】同第２の実施の形態において、現像剤滞留高さ規制の原理を示す側断面図である。
【図５】同第３の実施の形態における図であって、（Ａ）は現像剤プリセットシールを半分引き抜いた状態の側断面図、（Ｂ）は現像剤プリセットシールと現像剤収容室規制シールとを連結した状態の斜視図、（Ｃ）は前記連結状態の平面図である。
【図６】同第３の実施の形態における別の例の図であって、（Ａ）は環状のプリセットシールの側断面図、（Ｂ）は環状のプリセットシールを回転させて現像剤の一部を落下させる際の側断面図である。
【図７】同第４の実施の形態の側断面図である。
【図８】同第５の実施の形態の側断面図である。
【図９】従来例の側断面図である。
【図１０】従来例の正常な作用を示す図であって、（Ａ）は現像剤プリセットケースを水平状態に保った側断面図、（Ｂ）は前記水平状態で現像剤を落下させた側断面図である。
【図１１】従来例の不具合な作用を示す図であって、（Ａ）は現像剤プリセットケースが斜めの状態の側断面図、（Ｂ）は斜めの状態で現像剤プリセットシールを引き抜いた場合に、落下した現像剤に偏りが生じる状態を示す側断面図である。
【図１２】従来例の不具合を説明する図であって、（Ａ）は落下した現像剤の偏りを示す側断面図および正面図、（Ｂ）は現像スリーブの周方向における現像剤量を示すグラフ、（Ｃ）は現像スリーブの周方向におけるトナー濃度を示すグラフである。
【符号の説明】
Ａ …現像剤収容部
Ｇ …現像部
ＧＳ…現像装置
Ｋ …感光体
１ …感光体ドラム
２ …現像ケーシング
３ａ…現像剤
３ｂ…現像剤滞留部
４ …現像スリーブ
５ …マグネットローラ
５ａ…磁極
６ａ…現像ドクタ
６ｂ…プレドクタ
７ …現像剤収容室
８ …トナーホッパ
８ａ…トナー補給口
９ …アジテータ
１１ａ…トナー
１３…攪拌部材
２１…帯電手段
２２…現像手段
２３…クリーニング手段
２６…電源
３０…現像剤プリセットケース
３１…現像剤プリセットシール
３２…現像剤収容室規制シール
３４…糸状部材
３５…環状現像剤プリセットケース[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a developing device, a process cartridge integrally provided with the developing device, and an image forming apparatus to which the developing device is applied. In particular, when a developer preset case is set in the developing device, development at an initial setup operation is performed. The present invention relates to a developing device that eliminates unevenness of the agent.
[0002]
[Prior art]
Conventionally, a two-component development method is known as one of methods for developing an electrostatic latent image using toner. In the two-component development method, the toner is held on the surface of the magnetic carrier by the electrostatic force generated by the friction between the relatively large magnetic carrier contained in the developer and the minute toner, and when approaching the electrostatic latent image, The attracting force in the direction of the electrostatic latent image with respect to the toner by the electric field formed by the electrostatic latent image overcomes the coupling force between the toner and the magnetic carrier, and the toner is attracted and adhered to the electrostatic latent image by electrostatic force. The latent image is visualized. The developer used in this two-component development method is repeatedly used while replenishing the toner consumed by the development.
[0003]
FIG. 9 is a side sectional view of a developing device GS using a conventional two-component developing method, and FIGS. 10A and 10B are side sectional views of a developer preset case applied to the developing device.
In the conventional developing device GS, as shown in FIGS. 9, 10A and 10B, the user pulls out the seal 31 of the developer preset case 30 installed on the upper side of the developer accommodating chamber 7, and the developer. The developer 3 a is dropped into the storage chamber 7. Next, the developing device GS is set in a main body (not shown) of an image forming apparatus such as a copying machine, a FAX, or a printer, and when driven, the developer 3a in the developer containing chamber 7 is transferred to the developing sleeve 4 by the developing doctor ( It passes through the doctor blade 6a and is conveyed on the developing sleeve 4. Then, it stays upstream of the pre-doctor 6b, the formation of the developer retaining portion 3b begins, and the control of the image forming apparatus begins.
Here, reference numeral 1 is a photosensitive drum, 2 is a developing casing, 11a is toner, 13 is a stirring member, 21 is a charging means, and 23 is a cleaning means.
[0004]
10A shows a state when the developer preset seal 31 is pulled out from the developer preset case 30 (pulled in the direction of the arrow), and FIG. 10B shows the developer 3a after the seal 31 is pulled out. The state of is shown.
In this developing device GS, it is necessary to stabilize the toner concentration (mixing ratio of the magnetic carrier and the toner) by limiting the replenishment of the toner 11a by forming the developer retaining portion 3b. When the preset seal 31 is pulled out (see FIG. 10A), the developer 3a is uniformly set in the developer storage chamber 7 (see FIG. 10B).
[0005]
[Problems to be solved by the invention]
However, as shown in FIG. 11A, when the seal pull-out operation is performed by raising one side so as to incline in the longitudinal direction of the developer preset case 30, as shown in FIG. The developer storage chamber 7 is biased toward the lower side.
When the initial operation of the developing device is executed in this state, as shown in FIG. 12A, the developer amount in the developer accommodating chamber 7 and the upstream portion of the predoctor 6b are formed in the longitudinal direction of the developer preset case 30. The developer amount in the developer retaining part 3b is greatly biased. In such a state, the toner density of the developer on the developing sleeve 4 is largely biased. As a result, as shown in the graphs of FIGS. 12B and 12C, the toner density decreases on the lower side in the longitudinal direction of the developing sleeve 4, and when the image density is insufficient or severe, problems such as carrier adhesion occur. It will be generated.
[0006]
On the other hand, on the higher side in the longitudinal direction, the developer is insufficient, and a sufficient developer retaining portion 3b cannot be formed in front of the predoctor 6b. Therefore, the toner concentration increases, and if it is severe, scumming occurs. If the angle θ is about 20 to 30 degrees, it is almost unaffected and is made almost uniform in the developer accommodating chamber during the initial set-up operation. The problem occurs.
[0007]
Accordingly, an object of the present invention is to provide a developing device that eliminates the bias of the developer during the initial setup operation when the developer preset case is set in the developing device, a process cartridge integrally provided with the developing device, and An object of the present invention is to provide an image forming apparatus to which the developing device is applied.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the invention of claim 1 includes a developer storage chamber in which a developer preset case in which a developer has been sealed in advance is disposed above, and a hopper that supplies toner to the developer storage chamber. After the developer in the developer preset case has been dropped into the developer storage chamber, the toner supplied from the hopper is mixed and carried on the surface of the developer carrying member, and then the static on the photosensitive member. In a developing device for developing an electrostatic latent image with toner and then transferring the toner image onto a transfer sheet, a preset seal for previously closing an opening provided in the preset case, and closing the opening A developer retention height restriction seal that can be set, and the developer retention height restriction seal is connected to the preset seal, and the developer retention height restriction seal is connected in the same direction as the movement direction of the preset seal. Image agent retaining height regulating seal movable, performs a movement also the developer retaining height regulating seal in accordance with the movement of the preset seal, The developer retention height restriction seal moves to the position where the opening can be closed, An opening through which the developer can drop is provided between the preset seal and the developer retention height regulation seal.
[0009]
If you do this , The height of the developer dropped in the developer storage chamber is regulated, and even if the developing device is subjected to impact or misoperation during the initial setup operation, the developer will not be biased, and an image free from background stains and image density reduction will be obtained. It is done.
[0010]
Also , When the developing device is set in the image forming apparatus, the seal opening and the developer retention height restriction can be completed with one action (one operation).
[0011]
Claims The invention of 2 Since the developer sealing function and the developer retention height regulating function can be achieved with a single member, cost reduction and protection of the natural environment (for example, wasteful waste such as a seal with only a sealing function) Can not contribute).
[0012]
Claims 3 According to the present invention, at least one of a photoconductor, a charging unit, and a cleaning unit used for image formation is provided. Or 2 Described in of A process cartridge which is integrated with a developing device and is detachable from a main body of an image forming apparatus. According to this configuration, at least one of the photosensitive member, the charging unit, and the cleaning unit is integrally configured in the developing device that includes the developer and toner that is set and used in the main body of the image forming apparatus. As a result, the number of parts is reduced, and user operability can be improved.
[0013]
Claims 4 The invention of claim 1 Or 2 The weight average diameter of the developer applied to the developing device described in 4) is 4 to 15 μm. In this way, the resolution of the image obtained can be improved by setting the weight average diameter of the developer to 4 to 15 μm.
[0014]
Claims 5 The invention of claim 1, 2, Or 4 An image forming apparatus to which the developing device according to any one of the above is applied, wherein an alternating electric field is applied when an electrostatic latent image is developed on the photoconductor. In this way, when developing the latent image on the photosensitive member by the developing device, the vibration bias voltage obtained by superimposing the AC voltage on the DC voltage is applied, so that a high-definition image without roughness can be obtained.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on the illustrated embodiments.
FIG. 1 is a schematic diagram of a developing device GS according to the present embodiment. The difference between FIG. 1 and FIG. 9 is whether or not the seal of the developer preset case is pulled out, and the mechanical configuration of the developing device GS itself is the same.
[0016]
As shown in FIG. 1, the developing device GS includes a developing unit G and a photoconductor unit K.
The developing unit G is disposed on the side of the photosensitive drum 1 constituting the photosensitive unit K, and a part of the developing unit G is formed inside the developing casing 2 in which an opening is formed toward the photosensitive drum 1 from the opening. A developing sleeve 4 made of a non-magnetic material as a developer carrying member carrying a developer 3a made of toner and a magnetic carrier on the surface, and a magnet roller as a magnetic field generating means fixedly disposed inside the developing sleeve 4 5. A doctor blade 6a as a developer regulating member for regulating the amount of developer carried and conveyed on the developing sleeve 4, a developer accommodating chamber 7, a toner hopper 8 as a toner accommodating portion, and the like.
The photosensitive member K is unnecessary for the cylindrical photosensitive drum 1 which is a latent image carrier used in a copying machine (image forming apparatus), charging means 21 for charging the photosensitive drum 1, and unnecessary on the photosensitive drum 1. And a cleaning means 23 for removing objects.
[0017]
The developer accommodating chamber 7 is located between the developing sleeve 4 and the developer accommodating portion A that accommodates the developer that is not supplied to the developing position opposite to the photosensitive drum 1 and is prevented from advancing by the doctor blade 6a. (See FIG. 9). In the magnet roller 5 fixedly arranged inside the developer sleeve 4, the developer 3 a in the developer accommodating chamber 7 is carried on the developing sleeve 4 at a position facing the developer accommodating portion A. The magnetic pole 5a for this is arrange | positioned.
[0018]
Further, the toner hopper 8 has a toner replenishing port 8a facing the surface of the developing sleeve 4 adjacent to the upstream side of the developer accommodating portion A in the developer transport direction, and in a space adjacent to the toner replenishing port 8a. An agitator 9 is disposed as a toner stirring member that feeds the toner 11a in the toner hopper 8 while stirring the toner 11a toward the toner supply port 8a. The agitator 9 is set so that the position of the rotating shaft and the length of the wings are adjusted so that the outermost orbit of the agitator does not touch the developer.
[0019]
In the developing device GS having the above-described configuration, the developer 3a carried on the developing sleeve 4 moves on the sleeve toward the doctor blade 6a as the developing sleeve 4 rotates in the direction of arrow a (counterclockwise) in the drawing. It is transported and regulated by the doctor blade 6a to be thinned. The thinned developer 3a is conveyed to a developing region facing the photosensitive drum 1 rotating in the direction of arrow b (clockwise) in the drawing. In the developing area, the toner 11a is supplied to the electrostatic latent image formed on the photosensitive drum 1 in contact or non-contact, and the electrostatic latent image is visualized.
[0020]
Thereafter, with the rotation of the developing sleeve 4, the developer 3 a is transported on the sleeve to the side of the predoctor blade 6 b as a developer second restricting member as a developer supply port, and is sent out by the agitator 9 in the toner hopper 8. After taking in the new toner 11a supplied from the toner supply port 8a, the process returns to the developer accommodating portion A. The developer 3a containing the new toner 11a is increased in internal pressure at the restricting portion by the doctor blade 6a, and the toner of the developer 3a is frictionally charged. As described above, the toner in the developer 3a on the developing sleeve 4 can be charged by the internal pressure of the developer in the developer accommodating portion A. Therefore, a paddle, a screw or the like for charging or stirring the developer is used. A complicated stirring and conveying mechanism is not required.
[0021]
On the other hand, a part of the developer 3a not progressed by the doctor blade 6a without being supplied to the developing area is partly supplied to the toner replenishing port of the toner hopper 8 by the internal pressure and gravity of the developer 3a itself in the developer accommodating portion A. Move towards 8a. The developer 3a that has moved to the vicinity of the toner supply port 8a is attracted to the developing sleeve 4 side by the magnetic force of the magnetic pole 5a, and is conveyed to the doctor blade 6a side as the developing sleeve 4 rotates, thereby containing the developer. Circulate in part A. Further, in order to activate the stirring of the developer 3a in the developer container A, a stirring member 13 is provided in the developer container A. Since the stirring member 13 also serves as a developer regulating member on the developing sleeve 4, it is in the same rotational direction (counterclockwise) as the developing sleeve.
[0022]
In the developing device GS having the above configuration, when the toner replenished to the developer 3a increases and the toner density increases, the volume of the developer 3a increases accordingly. It overflows from the inside of the developer storage chamber 7 and closes the predoctor blade 6b. For this reason, the amount of the developer 3a on the developing sleeve 4 is reduced. Due to the reduction of the toner intake amount, the toner concentration of the developer 3a is always kept below a certain concentration.
On the contrary, when the toner concentration of the developer 3a is lowered, the volume of the developer 3a is reduced, so that the developer 3a does not block the predoctor blade 6b, so that a predetermined amount of toner is applied to the developer 3a on the developing sleeve 4. The toner density of the developer 3a is always kept at a certain density or higher. Thus, since the toner density can be controlled within a substantially constant range, complicated toner density control using a toner density sensor or a replenishing member is not necessary.
[0023]
Specific examples of development conditions of this development system are shown below.

[0024]

[0025]

[0026]
(1) First embodiment ... corresponding to claim 1
A first embodiment will be described.
Normally, when the process cartridge (developing device) GS is set in a horizontal state and the developer preset seal 31 is pulled out, all the developer in the developer preset case 30 moves into the developer accommodating chamber 7. At this time, the toner concentration set in the preset case is 5 wt%, and the developer amount is 64 g.
As shown in FIGS. 2A to 2C, a developer storage chamber regulation seal that is a “developer retention height regulating means” for partitioning between the developer preset case 30 and the developer storage chamber 7. 32 is arranged. In this way, even if the process cartridge is inclined, after the developer preset seal 31 is opened, the developer 3a falls into the developer preset case 30 due to the influence of the inclination of the developing device GS. A large change in the height of the developer in the developer storage chamber 7 can be regulated (FIG. 2B).
[0027]
That is, before the developer preset seal 31 is pulled out, it is in the state shown in FIG. 2 (A), and the developer 3 a is stored above the seal 31. Next, as shown in FIG. 2B, when the developer preset seal 31 is pulled out about half, about half of the stored developer 3a falls downward, and when the seal 31 is further pulled out, the remaining developer 3a. Falls. Therefore, as shown in FIG. 2C, even when the developing device GS is inclined, the developer 3a falls almost uniformly into the developer accommodating chamber 7.
Specifically, as shown in FIGS. 3A and 3B, the developer preset case 30 is partitioned into six parts, so that the developer 3a moves in the developer preset case 30. The developer 3a that is not partitioned falls into the developer accommodating chamber 7 almost directly below.
[0028]
(2) Second embodiment ... corresponding to claim 2
A second embodiment will be described.
After the developer 3a is dropped into the developer storage chamber 7 (see FIG. 1), for example, when the developing device GS is tilted, the developer 3a is also tilted, and the image density is insufficient as described in the prior art. In severe cases, problems such as carrier adhesion may occur. This embodiment prevents such a situation.
[0029]
As this prevention means, as shown in FIG. 4, development as a space restriction means for regulating the space portion of the developer accommodating chamber 7 between the lower surface side of the preset case 30 and the upper side of the developer accommodating chamber 7. An agent preset seal 32 may be disposed.
That is, as shown in FIGS. 5A, 5 </ b> B, and 5 </ b> C, the tip of the developer storage chamber restriction seal 32 wound in a roll shape and the folded portion of the developer preset seal 31 are connected to the thread-like member 34. And the developer accommodating chamber regulating seal 32 is interposed on the upper side of the developer accommodating chamber 7 simultaneously with the pulling-out operation of the developer preset seal 31.
In this way, when the developing device is set in the image forming apparatus, the opening of the seal and the restriction of the developer retention height can be completed with one action (one operation). Further, even when the developing device GS or the image forming apparatus (not shown) is tilted, it is possible to prevent the developer 3a from being inclined, and thus it is possible to prevent problems such as insufficient image density.
Further, it is desirable that the developer storage chamber restriction seal 32 be disposed on the side opposite to the drawing side of the developer preset seal 31. In this way, when the user pulls out the seal 31, the user can operate with the pulling side raised, and the operability is improved.
[0030]
(3) Third Embodiment A third embodiment corresponding to claim 3 will be described. In the second embodiment, the developer preset seal 31 and the developer storage chamber restriction seal 32 are configured separately (the developer preset case 31 and the developer preset seal 32 in FIG. 5). In contrast, the present embodiment is a case in which the developer preset case and the developer storage chamber regulation seal are configured integrally. Figure 6 As shown in (A), a belt-like developer preset seal 35 is rotatably wound around the periphery of the developer preset case 30 in the longitudinal direction. A developer dropping port 36 is formed in a part of the developer preset case 35.
[0031]
And figure 6 As shown in (B), by rotating the developer preset seal 35, the developer 3a can be dropped into the developer accommodating chamber 7 and at the same time the upper side of the developer accommodating chamber 7 can be regulated (FIG. 4). Note that the developer preset seal 35 is not displaced between the developer preset case 30 and the developer storage chamber 7 because the facing portion of the case and the developer storage chamber serves as a guard (positioning).
[0032]
(4) Fourth embodiment ... corresponding to claim 4
A fourth embodiment will be described.
FIG. 7 shows a main configuration of the developing device (process cartridge) of the present invention set in the image forming apparatus.
In FIG. 7, reference numeral 21 denotes a charging unit, 22 denotes a developing unit (developing unit G in FIG. 1), and 23 denotes a cleaning unit.
In the present embodiment, among the constituent elements such as the photosensitive drum 1, the charging device means 21, the developing means 22, and the cleaning means 23, a plurality of them are integrally coupled as a process cartridge, The process cartridge is configured to be detachable from an image forming apparatus main body such as a copying machine or a printer.
[0033]
In the image forming apparatus in which such a process cartridge is set, the photosensitive drum 1 is rotationally driven at a predetermined peripheral speed. In the rotating process, the photosensitive drum 1 is uniformly charged with a predetermined positive or negative potential on the peripheral surface thereof by the charging unit 21, and then image exposure unit (illustrated) such as slit exposure or laser beam scanning exposure. The electrostatic latent images are sequentially formed on the peripheral surface of the photosensitive drum 1 in response to the image exposure light (not shown), and the formed electrostatic latent images are toner developed by the developing means 22. The developed toner image is transferred to a transfer material fed in synchronization with the rotation of the photosensitive drum 1 between the photosensitive drum 1 and a transfer unit (not shown) from a paper feeding unit (not shown). It is sequentially transferred by means.
[0034]
The transfer material that has received the image transfer is separated from the surface of the photosensitive drum, introduced into an image fixing means (not shown), fixed on the image, and printed out as a copy (copy). The surface of the photosensitive drum 1 after the image transfer is cleaned by removing the transfer residual toner by the cleaning means 23, and after being further neutralized, it is repeatedly used for image formation.
[0035]
(5) Fifth embodiment ... corresponding to claim 5
A fifth embodiment will be described.
This embodiment is a case where the resolution of an image is improved. When the weight average diameter of the developer is 4 to 15 μm, the resolution of the obtained image is improved.
The weight average diameter is measured by the following procedure.
First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used.
[0036]
Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. Volume distribution and number distribution are calculated. From the obtained distribution, the weight average particle diameter (D4) and the number average particle diameter of the toner can be obtained.
[0037]
As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6.35 to less than 8.00 μm; Less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; less than 20.20 to less than 25.40 μm; less than 25.40 to less than 32.00 μm; using 13 channels less than 32.00 to less than 40.30 μm, and particles having a particle size of 2.00 μm to less than 40.30 μm set to target.
[0038]
"Materials that make up the developer"
It is a description that leads to both one component and two components. Materials such as a binder resin and a colorant constituting the toner are listed.
The proportion of the total toner is 75% to 93% for the binder resin, 3% to 10% for the colorant, 3% to 8% for the release agent, and 1% to 7% for the other components.
Examples of the binder resin to be used include homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene, and substituted products thereof; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer Polymer, styrene-vinyl naphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl Examples thereof include a methyl ether copolymer, a styrene-vinyl ethyl ether copolymer, and a styrene-vinyl methyl ketone.
[0039]
As the colorant, conventionally known inorganic or organic dyes / pigments can be used. For example, carbon black, aniline black, acetylene black, naphthol yellow, Hansa Yellow, Rhodamun Lake, Alizarin Lake, Bengala, Examples include phthalocyanine blue and indanthrene blue.
[0040]
If necessary, a magnetic material can be used as a colorant.
Magnetic materials include magnetite, γ-iron oxide, ferritic iron, iron oxide such as excess ferrite; magnetic metal such as iron, cobalt and nickel; iron oxide or magnetic metal and cobalt, tin, titanium, copper, lead, Examples thereof include a composite metal oxide alloy or a mixture with a metal such as zinc, magnesium, manganese, aluminum, and silicon.
These magnetic particles preferably have an average particle diameter in the range of 0.05 to 1.0 μm, more preferably in the range of 0.1 to 0.6 μm, and still more preferably in the range of 0.1 to 0.4 μm.
These magnetic particles preferably have a BET specific surface area by nitrogen adsorption method of 1 to 20 m. ² / G, especially 2.5 to 12 m ² / G is preferable, and the Mohs hardness is preferably in the range of 5-7.
[0041]
The shape of the magnetic particles includes octahedrons, hexahedrons, spheres, needles, and scales, but octahedrons, hexahedrons, and spheres with less anisotropy are preferred. "
When used as a magnetic toner, the magnetic toner particles containing the magnetic material may contain 10 to 150 parts by mass, preferably 20 to 120 parts by mass of the magnetic material, based on 100 parts by mass of the binder resin.
[0042]
In the toner of the present invention, a small amount of an additive can be used within a range that does not have a substantial adverse effect.
Examples of the additives include lubricant powders such as Teflon powder, zinc stearate powder and polyvinylidene fluoride powder; abrasives such as cerium oxide powder, silicon carbide powder and strontium titanate powder; for example, titanium oxide powder and aluminum oxide powder. Examples of such fluidity-imparting agents or anti-caking agents; conductivity-imparting agents such as carbon black powder, zinc oxide powder and tin oxide powder; and organic or inorganic fine particles having opposite polarity.
[0043]
Further, a release agent can be added to improve the fixing property.
Examples of the release agent include paraffin wax and derivatives thereof, microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, polyolefin wax and derivatives thereof, and carnauba wax and derivatives thereof. Derivatives include oxides, block copolymers with vinyl monomers, and graft modified products of vinyl monomers.
In addition, alcohols, fatty acids, acid amides, esters, ketones, hydrogenated castor oil and derivatives thereof, plant waxes, animal waxes, mineral waxes, and petrolactams can also be used.
[0044]
As the charge control agent for controlling the toner to be negatively charged, for example, organometallic complexes and chelate compounds are effective, and monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acid metal complexes, aromatic dicarboxylic acids. -Based metal complexes. Others include aromatic hydroxycarboxylic acids, aromatic mono and polycarboxylic acids and their metal salts, their anhydrides, their esters, and phenol derivatives such as bisphenol.
[0045]
Examples of charge control agents for controlling the toner to be positively charged include modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate. And onium salts such as phosphonium salts which are analogs thereof, and lake pigments thereof, triphenylmethane dyes and lake pigments thereof. Acid, lauric acid, gallic acid, ferricyanide, ferrocyanide).
The number average particle diameter of the particulate charge control agent is preferably 4 μm or less, more preferably 3 μm or less.
[0046]
When these charge control agents are internally added to the toner particles, the toner particles are preferably 0.1 to 20 parts by weight, more preferably 0.2 to 10 parts by weight with respect to 100 parts by weight of the binder resin. It is good to contain a mass part.
These toners are generally used as toner additives, for example, fluidizing agents such as colloidal silica, metal oxides such as titanium oxide and aluminum oxide, and abrasives such as silicon carbide. Further, a lubricant such as a fatty acid metal salt may be contained.
[0047]
The inorganic fine powder is preferably used in an amount of 0.1 to 2% by weight based on the toner. If it is less than 0.1% by weight, the effect of improving toner aggregation is poor, and if it exceeds 2% by weight, problems such as toner scattering between fine wires, contamination in the machine, scratches and abrasion of the photoreceptor tend to occur. is there.
As a method of mixing the additive with the toner, a conventionally known method may be used, and the additive may be mixed by an apparatus such as a Henschel mixer or a speed kneader.
As a method for producing toner powder after toner kneading and cooling, a conventionally known method may be used. For example, kneading and cooling may be followed by pulverizing with a jet mill and classification.
[0048]
The electrostatic image developing toner thus produced can be used as a dry one-component developer and a dry two-component developer.
When used as a two-component developer, the mixing ratio of toner and carrier is generally about 0.5 to 6.0 parts by weight of toner with respect to 100 parts by weight of carrier.
When used as a dry two-component developer, the carrier and toner of the present invention are used in such a manner that the toner particles adhere to the carrier surface of the carrier particles and occupy 30 to 90% of the surface area. It is preferable to do this.
[0049]
The carrier core particles constituting the developer used in the present invention may be those conventionally known, such as ferromagnetic metals such as iron, cobalt and nickel; alloys and compounds such as magnetite, hematite and ferrite; And a composite of fine body particles and a resin.
The carrier used in the present invention is preferably coated with a resin for the purpose of increasing durability.
[0050]
Examples of the resin that forms the coating layer include polyolefin resins such as polyethylene, polypropylene, chlorinated polyethylene, and chlorosulfonated polyethylene; polystyrene, acrylic (eg, polymethyl methacrylate), polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, Polyvinyl and polyvinylidene resins such as polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, and polybiliketones; vinyl chloride-vinyl acetate copolymers; silicone resins composed of organosiloxane bonds or modified products thereof (eg, alkyd resins, polyester resins, epoxies) Modified products by resin, polyurethane, etc.); polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoro Fluorine resins such as styrene, polyamides, polyesters, polyurethanes, polycarbonates; - urea amino resins such as formaldehyde resins, epoxy resins and the like.
Of these, silicone resin or a modified product thereof, or a fluorine resin, particularly a silicone resin or a modified product thereof is preferable in terms of preventing toner spent.
[0051]
As a method for forming the coating layer, the coating layer forming liquid may be applied to the surface of the carrier core particle by means of a spraying method, a dipping method, or the like, as in the past.
The thickness of the coating layer is preferably from 0.1 to 20 μm.
Concrete example
Production example as a two-component developer

The mixture having the above composition was melt-kneaded and then pulverized and classified.
[0052]
Furthermore, 0.3 part by weight of hydrophobic silica was mixed with 100 parts by weight of the base coloring particles to obtain a toner having an average particle size of 9.0 μm.
Further, 2 parts by weight of polyvinyl alcohol and 60 parts by weight of water were placed in a ball mill with respect to 100 parts by weight of magnetite prepared by a wet method to prepare a magnetite slurry.
This slurry was sprayed and granulated with a spray dryer to obtain spherical particles.
The particles were fired in a nitrogen atmosphere at a temperature of 1000 ° C. for 3 hours and then cooled to obtain core particles 1.

The said mixture was disperse | distributed for 20 minutes with the homomixer, and the coating layer forming liquid 1 was prepared.
This coating layer forming liquid was coated on the surface of 1000 parts by weight of the core particles 1 using a fluidized bed coating apparatus to obtain a silicone resin-coated carrier.
The magnetic carrier was mixed at a ratio of 2.5 parts by weight of toner to 97.5 parts by weight to prepare a two-component developer.
[0053]
(6) Sixth embodiment ... corresponding to claim 6
A sixth embodiment will be described.
In FIG. 8, during development, a vibration bias voltage in which an AC voltage is superimposed on a DC voltage is applied to the developing sleeve 4 as a developing bias by the power source 26. The background portion potential and the image portion potential are located between the maximum value and the minimum value of the vibration bias potential. As a result, an alternating electric field whose direction changes alternately is formed in the developing means 24. In this alternating electric field, the toner and carrier of the developer vibrate vigorously, and the toner flies off the photosensitive drum 1 while shaking off the electrostatic binding force to the developing sleeve 4 and the carrier, corresponding to the latent image on the photosensitive drum 1. And adhere.
[0054]
The difference (the peak-to-peak voltage) between the maximum value and the minimum value of the vibration bias voltage is preferably 0.5 to 5 kV, and the frequency is preferably 1 to 10 kHz. As the waveform of the vibration bias voltage, a rectangular wave, a sine wave, a triangular wave, or the like can be used. As described above, the DC voltage component of the vibration bias is a value between the background part potential and the image part potential, but the value closer to the background part potential than the image part potential is more likely to cover the background part potential region. This is preferable for preventing toner adhesion.
[0055]
When the vibration bias voltage waveform is a rectangular wave, the duty ratio is preferably 50% or less. Here, the duty ratio is a ratio of time during which the toner is directed to the photosensitive member during one period of the vibration bias. By doing so, the difference between the peak value at which the toner is directed to the photoreceptor and the time average value of the bias can be increased, so that the movement of the toner is further activated and the potential of the latent image surface is increased. It can adhere to the distribution and improve the roughness and resolution. In addition, since the difference between the peak value of the carrier having a charge opposite to that of the toner and the time average value of the bias toward the photosensitive member can be reduced, the movement of the carrier is reduced, and the background portion of the latent image is reduced. The probability of carriers adhering to the substrate can be greatly reduced.
[0056]
【Effect of the invention】
As described above, according to the present invention, the following effects can be exhibited. According to claim 1 , The height of the developer dropped in the developer storage chamber is regulated, and even if the developing device is subjected to impact or misoperation during the initial setup operation, the developer will not be biased, and an image free from background stains and image density reduction will be obtained. It is done. Also, When the developing device is set in the image forming apparatus, the seal opening and the developer retention height restriction can be completed with one action (one operation).
[0057]
Claim 2 For example, by providing an annular developer preset seal on the outer periphery of the developer preset case, the developer sealing function and the developer retention height regulating function can be achieved with a single member. Can contribute to cost reduction and protection of the natural environment. Claim 3 According to the present invention, at least one of the photosensitive member, the charging unit, and the cleaning unit is integrally formed in the developing device that includes the developer and the toner that is set and used in the image forming apparatus main body. The number of parts is reduced, and user operability can be improved.
[0058]
Claim 4 Since the weight average diameter of the developer is 4 to 15 μm, the resolution of the obtained image is improved. Claim 5 Accordingly, when developing the latent image on the image carrier by the developing device, the vibration bias voltage obtained by superimposing the AC voltage on the DC voltage is applied, so that a high-definition image without roughness can be obtained.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a first embodiment of the present invention.
FIGS. 2A and 2B are diagrams for explaining the operation of the first embodiment, in which FIG. 2A is a state in which a developer preset case is slanted, FIG. 2B is a state in which a developer preset seal is half-drawn; C) is a state where all the developer preset seals are pulled out.
3A is a side cross-sectional view of the interior of a developer preset case divided into six parts, and FIG. 3B is a side cross-sectional view illustrating a state in which the developer preset seal is pulled out halfway. FIG.
FIG. 4 is a side sectional view showing the principle of developer retention height regulation in the second embodiment.
5A is a side sectional view of the third embodiment in which a developer preset seal is half-drawn, and FIG. 5B is a developer preset seal and a developer storage chamber regulation seal. The perspective view of the state which connected with (C) is a top view of the said connection state.
6A and 6B are diagrams showing another example in the third embodiment, in which FIG. 6A is a side sectional view of an annular preset seal, and FIG. It is a sectional side view at the time of dropping a part.
FIG. 7 is a side sectional view of the fourth embodiment.
FIG. 8 is a side sectional view of the fifth embodiment.
FIG. 9 is a sectional side view of a conventional example.
10A and 10B are diagrams showing normal operation of a conventional example, in which FIG. 10A is a side sectional view of a developer preset case kept in a horizontal state, and FIG. 10B is a side where the developer is dropped in the horizontal state. It is sectional drawing.
FIGS. 11A and 11B are diagrams showing a malfunction of the conventional example, in which FIG. 11A is a side sectional view of a developer preset case in an oblique state, and FIG. 11B is a case where the developer preset seal is pulled out in an oblique state; FIG. 6 is a side cross-sectional view showing a state in which the developer that has fallen is biased.
FIGS. 12A and 12B are diagrams for explaining a problem in the conventional example, in which FIG. 12A is a side sectional view and a front view showing a bias of the dropped developer, and FIG. 12B is a developer amount in the circumferential direction of the developing sleeve; Graph (C) is a graph showing the toner density in the circumferential direction of the developing sleeve.
[Explanation of symbols]
A: Developer container
G ... Developer
GS ... Developing device
K: Photoconductor
1 ... Photosensitive drum
2 ... Developing casing
3a: Developer
3b: developer retaining part
4 ... Developing sleeve
5 ... Magnet roller
5a ... Magnetic pole
6a ... Development doctor
6b ... Predoctor
7: Developer chamber
8 ... Toner hopper
8a ... Toner supply port
9… Agitator
11a ... Toner
13: Stirring member
21: Charging means
22: Developing means
23. Cleaning means
26 ... Power supply
30 ... Developer preset case
31 ... Developer preset seal
32 ... Developer chamber restriction seal
34 ... thread-like member
35 ... Annular developer preset case

Claims (5)

A developer storage chamber in which a developer preset case in which a developer has been sealed in advance is disposed; and a hopper for supplying toner to the developer storage chamber. The developer in the developer preset case is After the toner supplied from the hopper is mixed with the developer dropped in the storage chamber and carried on the surface of the developer carrying member, the electrostatic latent image on the photoreceptor is visualized with the toner, and then the toner In a developing device for transferring an image onto transfer paper,
A preset seal that pre-closes the opening provided in the preset case;
A developer retention height restriction seal that is set so that the opening can be closed;
The developer retention height restriction seal is connected to the preset seal, and the developer retention height restriction seal can be moved in the same direction as the movement of the preset seal. The developer staying height restriction seal also moves, the developer staying height restriction seal moves to a position where the opening can be closed, and the developer is placed between the preset seal and the developer staying height restriction seal. A developing device comprising a dropable opening.   2. The developing device according to claim 1, wherein the developer retention height restriction seal is constituted by the preset seal.   At least one of the photosensitive member, the charging unit, and the cleaning unit used for image formation is configured integrally with the developing device according to claim 1 or 2 and is detachable from the image forming apparatus main body. A process cartridge.   The developing device according to claim 1, wherein the weight average diameter of the developer to be applied is 4 to 15 μm.   An image forming apparatus to which the developing device according to claim 1 is applied, wherein an alternating electric field is applied when an electrostatic latent image is developed on the photosensitive member. An image forming apparatus.

Images