JP3893253B2 - Toner, image forming method and process cartridge - Google Patents

Description

（式中、Ｒはエチレンまたはプロピレン基であり、ｘ，ｙはそれぞれ０以上の整数であり、かつ、ｘ＋ｙの平均値は０〜１０である。）
【００５９】
さらに、２価のアルコール成分として式（Ｂ）で示されるジオールが挙げられる。
【００６０】
【化２】

【００６１】
２価の酸成分としては、フタル酸、テレフタル酸、イソフタル酸、無水フタル酸などのベンゼンジカルボン酸また、はその無水物、低級アルキルエステル；こはく酸、アジピン酸、セバシン酸、アゼライン酸の如きアルキルジカルボン酸また、はその無水物また、はその低級アルキルエステル；ｎ−ドデセニルコハク酸、ｎ−ドデシルコハク酸の如きアルケニルコハク酸もしくはアルキルコハク酸、また、はその無水物また、はその低級アルキルエステル；フマル酸、マレイン酸、シトラコン酸、イタコン酸などの不飽和ジカルボン酸また、はその無水物また、はその低級アルキルエステル等のジカルボン酸及びその誘導体が挙げられる。
【００６２】
また、架橋成分としても働く３価以上のアルコール成分と３価以上の酸成分を併用することが好ましい。
【００６３】
３価以上の多価アルコール成分としては、ソルビトール、１，２，３，６−ヘキサンテトロール、１，４−ソルビタン、ペンタエリスリトール、ジペンタエリスリトール、トリペンタエリスリトール、１，２，４−ブタントリオール、１，２，５−ペンタントリオール、グリセロール、２−メチルプロパントリオール、２−メチル−１，２，４−ブタントリオール、トリメチロールエタン、トリメチロールプロパン、１，３，５−トリヒドロキシベンゼン等が挙げられる。
【００６４】
また、３価以上の多価カルボン酸成分としては、例えばトリメリット酸、ピロメリット酸、１，２，４−ベンゼントリカルボン酸、１，２，５−ベンゼントリカルボン酸、２，５，７−ナフタレントリカルボン酸、１，２，４−ナフタレントリカルボン酸、１，２，４−ブタントリカルボン酸、１，２，５−ヘキサントリカルボン酸、１，３−ジカルボキシル−２−メチル−２−メチレンカルボキシプロパン、テトラ（メチレンカルボキシル）メタン、１，２，７，８−オクタンテトラカルボン酸、エンポール三量体酸、及びこれらの無水物、低級アルキルエステル；次式
【００６５】
【化３】

（式中、Ｘは炭素数１以上の側鎖を１個以上有する炭素数１〜３０のアルキレン基また、はアルケニレン基）
で表わされるテトラカルボン酸及びこれらの無水物及びそれらの低級アルキルエステル等の多価カルボン酸類及びその誘導体が挙げられる。
【００６６】
アルコール成分としては４０〜６０ｍｏｌ％、好ましくは４５〜５５ｍｏｌ％、酸成分としては６０〜４０ｍｏｌ％、好ましくは５５〜４５ｍｏｌ％であることが好ましい。また３価以上の多価アルコールの成分は、全成分中の１〜６０ｍｏｌ％であることが好ましい。上記ポリエステル樹脂も通常一般に知られている縮重合によって得られる。
【００６７】
本発明のトナーは、磁性材料を含有した磁性トナーとして用いられることが好ましい。使用できる磁性材料としては、鉄、コバルト、ニッケル、銅、マグネシウム、マンガン、アルミニウム、ケイ素などの元素を含む金属酸化物などがある。これら磁性粒子は、窒素吸着法によるＢＥＴ比表面積が好ましくは１〜２０ｍ²／ｇ、特に２．５〜１２ｍ²／ｇ、更にモース硬度が５〜７の磁性粉が好ましい。磁性体の形状としては、８面体、６面体、球形、針状、鱗片状などがあるが、８面体、６面体、球形等の異方性の少ないものが好ましい。等方性の形状を有するものは、トナー中で良好な分散を達成することができるからである。磁性体の平均粒径としては０．０５〜１．０μｍが好ましく、さらに好ましくは０．１〜０．６μｍ、さらには、０．１〜０．４μｍが好ましい。
【００６８】
上記磁性材料は、トナー結着樹脂１００質量部に対し４０〜２００質量部添加するのが好ましく、特に好ましくは５０〜１５０質量部である。４０質量部未満ではトナーの搬送性が不十分であり、トナー容器等への付着・残存などを起こしやすくなったり、現像剤担持体上のトナー層にムラが生じ、画像ムラとなる傾向があり、さらにトナーの帯電の過剰な上昇に起因する画像濃度の低下が生じ易い傾向である。また、２００質量部を超える場合にはトナーの帯電が充分には得られなくなるために、画像濃度低下が生じやすくなる。
【００６９】
本発明において、磁性酸化鉄の各物性は以下の方法により測定される。
【００７０】
（１）磁性酸化鉄の粒径及び形状：透過型電子顕微鏡（ＴＥＭ）Ｈ−７００Ｈ、Ｈ−８００、Ｈ−７５００（いずれも日立製作所製）または、走査型電子顕微鏡（ＳＥＭ）Ｓ−８００または、Ｓ−４７００（いずれも日立製作所製）を用い、磁性酸化鉄を２０，０００〜２００，０００倍で撮影し、１〜１０倍の焼き付け倍率として、任意の倍率で試料を観察することができる。粒径は、０．０３μｍ以上の粒子１００個をランダムに選び出して、各粒子の最大長（μｍ）を計測し、その平均をもって個数平均粒径とする。
【００７１】
（２）ＢＥＴ比表面積：ＢＥＴ比表面積は、湯浅アイオニクス（株）製、全自動ガス吸着量測定装置：オートソーブ１を使用し、吸着ガスに窒素を用い、ＢＥＴ多点法により求める。なお、サンプルの前処理としては、５０℃で１時間の脱気を行う。
【００７２】
本発明のトナーは、示差走査熱量計（ＤＳＣ）により測定される昇温時のＤＳＣ曲線に少なくとも一つの吸熱ピークを有し、該吸熱ピークが１２０〜１６０℃、好ましくは１２０〜１５０℃、より好ましくは１２５〜１４５℃に存在することが好ましい。吸熱ピークは２つ以上存在していてもよいが、その場合は１２０〜１６０℃に少なくとも１つの吸熱ピークを有することが好ましい。昇温時のＤＳＣ曲線からは、トナーの吸熱に伴う融解挙動を見ることができる。吸熱ピークが１２０〜１６０℃に存在することでトナーが摩擦熱に対して強くなり、長時間の使用においてもトナーに滑り性を確保でき、適度な耐付着性・流動性を確保できる。
【００７３】
吸熱ピークが１２０℃未満の温度にのみ存在するならば、熱的に軟化しやすくなるために容器内でのトナーの付着が起こりやすくなり、トナー残量検出手段に付着しやすくなるために、トナーの動きが滞り、画像濃度・カブリ等の現像性が悪化したり、トナー搬送性が悪化し、フェーディング現象を発生したり、高温下や、高耐久時に機内が昇温した場合などでトナー残量検知精度が劣ることになる。また、吸熱ピークが１６０℃を超えた温度にのみ存在すると、トナー中の各材料の分散が悪化し、カブリが悪化する場合がある。本発明のトナーの吸熱ピークは、トナーに含有されるワックスに起因するものであり、適当なワックスを選択してトナーに含有させることによって所望の吸熱ピークを得ることができる。このような吸熱ピークをトナーに付与することができるワックスは、その離型性から、トナーの付着性に対する影響が大きく、トナーに効果的に良好な流動特性を付与することができる。
【００７４】
本発明においては、トナーのＤＳＣ曲線は、示差走査熱量計（ＤＳＣ測定装置）、例えばＤＳＣ−７（パーキンエルマー社製）やＤＳＣ２９２０（ＴＡインスツルメンツジャパン社製）を用い、ＡＳＴＭ Ｄ３４１８−８２に準じて測定を行う。ＤＳＣ曲線は、１回昇温、降温させ前履歴を取った後、昇温速度１０℃／ｍｉｎで昇温させた時に測定されるＤＳＣ曲線を用いる。
【００７５】
本発明のトナーは、荷電制御剤として、有機金属化合物を用いることが好ましく、特に有機化合物を配位子や対イオンとして含有するものが有用である。このような金属錯体としては、帯電性の観点から、金属錯体型モノアゾ化合物が好ましく用いられる。金属錯体型モノアゾ化合物としては、特公昭４１−２０１５３号、同４２−２７５９６号、同４４−６３９７号、同４５−２６４７８号公報などに記載されているモノアゾ染料の金属錯体などがある。特に分散性・帯電性の面などから、下記一般式（Ｉ）で表わされる金属錯体型モノアゾ化合物であることが好ましく、中でも、中心金属が鉄である金属錯体型モノアゾ鉄錯体を用いることが好ましい。さらに好ましくは、下記一般式（ＩＩ）で表わされるモノアゾ鉄錯体を用いることである。
【００７６】
【化４】

【００７７】
【化５】

［式中、Ｘ₁，Ｘ₂；水素原子，低級アルキル基，低級アルコキシ基，ニトロ基，ハロゲン原子
ｍ，ｍ’；１〜３の整数
Ｙ₁，Ｙ₃；水素原子，Ｃ₁〜Ｃ₁₈のアルキル，アルケニル，スルホンアミド，メシル，スルホン酸，カルボキシエステル，ヒドロキシ，Ｃ₁〜Ｃ₁₈のアルコキシ，アセチルアミノ，ベンゾイル，アミノ基，ハロゲン原子
ｎ，ｎ’；１〜３の整数
Ｙ₂，Ｙ₄；水素原子，ニトロ基
（上記のＸ₁とＸ₂，ｍとｍ’，Ｙ₁とＹ₃，ｎとｎ’，Ｙ₂とＹ₄は同一でも異なっていても良い。）
Ａ⁺；アンモニウムイオン，アルカリ金属イオン、水素イオンの混合よりなる。］
【００７８】
上記金属錯体型モノアゾ化合物の含有量は、トナー結着樹脂１００質量部に対し、０．０５〜５質量部が好ましく、特に０．２〜３質量部が好ましい。該金属錯体型モノアゾ化合物の含有量が多過ぎると、トナーの流動性が悪化し、カブリが生じやすく、一方、少な過ぎると充分な帯電量が得られにくい。
【００７９】
本発明において着色剤としては、任意の適当な顔料または染料が使用される。トナー着色剤は周知であって、例えば顔料としてカーボンブラック、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、ローダミンレーキ、アリザリンレーキ、ベンガラ、フタロシアニンブルー、インダンスレンブルー等がある。これらは定着画像の光学濃度を維持するのに必要充分な量が用いられ、樹脂１００質量部に対し０．１〜２０質量部、好ましくは０．２〜１０質量部の添加量が良い。また同様の目的で、さらに染料が用いられる。例えばアゾ系染料、アントラキノン系染料、キサンテン系染料、メチン系染料等があり樹脂１００質量部に対し０．１〜２０質量部、好ましくは０．３〜１０質量部の添加量が良い。
【００８０】
本発明のトナーに含有されるワックスは、示差走査熱量計（ＤＳＣ）により測定される昇温時のＤＳＣ曲線に少なくとも一つの吸熱ピークを有し、該吸熱ピークが１２０〜１６０℃、好ましくは１２０〜１５０℃、より好ましくは１２５〜１４５℃に存在することが好ましい。吸熱ピークは２つ以上存在していてもよいが、その場合は１２０〜１６０℃に少なくとも１つの吸熱ピークを有することが好ましい。ワックスが上記温度領域に吸熱ピークを有することで、トナーに好ましい吸熱特性を付与することができる。
【００８１】
本発明のトナーに含有されるワックスは、低分子量ポリエチレン、低分子量ポリプロピレン、オレフィンの共重合物、マイクロクリスタリンワックス、パラフィンワックス、フィッシャートロプシュワックスの如き脂肪族炭化水素系ワックス；酸化ポリエチレンワックスの如き脂肪族炭化水素系ワックスの酸化物または、それらのブロック共重合物；カルナバワックス、モンタン酸エステルワックスの如き脂肪酸エステルを主成分とするワックス類；脱酸カルナバワックスの如き脂肪酸エステル類を一部または全部を脱酸化したものなどが挙げられる。さらに、パルミチン酸、ステアリン酸、モンタン酸、あるいは更に長鎖のアルキル基を有する長鎖アルキルカルボン酸類の如き飽和直鎖脂肪酸類；ブラシジン酸、エレオステアリン酸、バリナリン酸の如き不飽和脂肪酸類；ステアリルアルコール、アラルキルアルコール、ベヘニルアルコール、カルナウビルアルコール、セリルアルコール、メリシルアルコール、あるいは更に長鎖のアルキル基を有する長鎖アルキルアルコール類の如き飽和アルコール類；ソルビトールの如き多価アルコール類；リノール酸アミド、オレイン酸アミド、ラウリン酸アミドの如き脂肪酸アミド類；メチレンビスステアリン酸アミド、エチレンビスカプリン酸アミド、エチレンビスラウリン酸アミド、ヘキサメチレンビスステアリン酸アミドの如き飽和脂肪酸ビスアミド類、エチレンビスオレイン酸アミド、ヘキサメチレンビスオレイン酸アミド、Ｎ，Ｎ’−ジオレイルアジピン酸アミド、Ｎ，Ｎ’−ジオレイルセバシン酸アミドの如き不飽和脂肪酸アミド類；ｍ−キシレンビスステアリン酸アミド、Ｎ，Ｎ’−ジステアリルイソフタル酸アミドの如き芳香族系ビスアミド類；脂肪族炭化水素系ワックスにスチレンやアクリル酸の如きビニル系モノマーを用いてグラフト化させたワックス類；ベヘニン酸モノグリセリドの如き脂肪酸と多価アルコールの部分エステル化物；植物性油脂を水素添加することによって得られるヒドロキシ基を有するメチルエステル化合物などが挙げられる。
【００８２】
好ましく用いられるワックスとしては、アルキレンを高圧下でラジカル重合あるいは低圧下でチーグラー触媒、メタロセン触媒または、その他の触媒を用いて重合した低分子量のアルキレンポリマー；高分子量のアルキレンポリマーを熱分解して得られるアルキレンポリマー；アルキレンポリマーを重合する際に副生する低分子量アルキレンポリマーを分離精製したもの；一酸化炭素及び水素からなる合成ガスからアーゲ法により得られる炭化水素の蒸留残分から、あるいは、これらを水素添加して得られる合成炭化水素などから、特定の成分を抽出分別したワックスが挙げられる。これらワックスには酸化防止剤が添加されていてもよい。さらに、直鎖状のアルコール、脂肪酸、酸アミド、エステルあるいは、モンタン系誘導体で形成されるワックスが挙げられる。また、脂肪酸等の不純物を予め除去してあるものも好ましい。
【００８３】
特に好ましいワックスは、メタロセン触媒により重合されたポリエチレン、ポリプロピレン、エチレン−プロピレン共重合体、エチレン−αオレフィン共重合体、プロピレン−αオレフィン共重合体である。これらによりトナーに耐付着性・流動性が付与され好ましい。
【００８４】
本発明に使用されるワックスは、結着樹脂１００質量部に対して０．１〜１５質量部、好ましくは０．５〜１２質量部添加されるのが効果的であり、また、複数のワックスを併用することも好ましい。
【００８５】
また、本発明のトナーには、環境安定性、帯電安定性、現像性、流動性、保存性向上のため、無機微粉体が混合されていることが好ましい。無機微粉体はトナーに外添されていることが好ましい。無機微粉体は疎水性無機微粉体であることが好ましい。無機微粉体の例としては、シリカ微粉末、酸化チタン微粉末または、それらの疎水化物が挙げられる。それらは、単独あるいは併用して用いることが好ましい。
【００８６】
シリカ微粉体としては、ケイ素ハロゲン化合物の蒸気相酸化により生成された乾式法またはヒュームドシリカと称される乾式シリカ及び水ガラス等から製造される湿式シリカの両方が挙げられるが、表面及び内部にあるシラノール基が少なく、製造残渣のない乾式シリカの方が好ましい。
【００８７】
さらにシリカ微粉体は疎水化処理されているものが好ましい。疎水化処理するには、シリカ微粉体と反応あるいは物理吸着する有機ケイ素化合物で化学的に処理することによって付与される。好ましい方法としては、ケイ素ハロゲン化合物の蒸気相酸化により生成された乾式シリカ微粉体をシラン化合物で処理した後、あるいはシラン化合物で処理すると同時にシリコーンオイルの如き有機ケイ素化合物で処理する方法が挙げられる。
【００８８】
疎水化処理に使用されるシラン化合物としては、ヘキサメチルジシラザン、トリメチルシラン、トリメチルクロルシラン、トリメチルエトキシシラン、ジメチルジクロルシラン、メチルトリクロルシラン、アリルジメチルクロルシラン、アリルフェニルジクロルシラン、ベンジルジメチルクロルシラン、ブロムメチルジメチルクロルシラン、α−クロルエチルトリクロルシラン、β−クロルエチルトリクロルシラン、クロルメチルジメチルクロルシラン、トリオルガノシランメルカプタン、トリメチルシリルメルカプタン、トリオルガノシリルアクリレート、ビニルジメチルアセトキシシラン、ジメチルエトキシシラン、ジメチルジメトキシシラン、ジフェニルジエトキシシラン、ヘキサメチルジシロキサン、１，３−ジビニルテトラメチルジシロキサン、１，３−ジフェニルテトラメチルジシロキサンが挙げられる。
【００８９】
有機ケイ素化合物としては、シリコーンオイルが挙げられる。好ましいシリコーンオイルとしては、２５℃における粘度がおよそ３０〜１，０００ｍｍ²／ｓのものが用いられる。例えばジメチルシリコーンオイル、メチルフェニルシリコーンオイル、α−メチルスチレン変性シリコーンオイル、クロルフェニルシリコーンオイル、フッ素変性シリコーンオイルが好ましい。
【００９０】
特に好ましい方法としては、ジメチルシリコーンオイルで処理する方法が挙げられる。ジメチルシリコーンオイルで疎水化処理されたシリカ微粉体は、適度な疎水性を有し、且つ滑り性にも優れるため、長期の使用において、トナー容器やトナー残量検出手段に付着したり、トナーが現像スリーブに融着して画像濃度が低下することを効果的に防ぐことができる。
【００９１】
シリコーンオイル処理の方法は、シラン化合物で処理されたシリカ微粉体とシリコーンオイルとをヘンシェルミキサーの如き混合機を用いて直接混合しても良いし、ベースとなるシリカヘシリコーンオイルを噴射する方法によっても良い。あるいは適当な溶剤にシリコーンオイルを溶解あるいは分散せしめた後、ベースのシリカ微粉体とを混合し、溶剤を除去して作製しても良い。
【００９２】
シリカ微粉体の好ましい疎水化処理として、ジメチルジクロロシランで処理し、次いでヘキサメチルジシラザンで処理し、次いでシリコーンオイルで処理することにより調製する方法が挙げられる。
【００９３】
上記のようにシリカ微粉体を２個以上のシラン化合物で処理し、後にオイル処理することが疎水化度を効果的に上げることができ、好ましい。
【００９４】
上記シリカ微粉体における疎水化処理、更には、オイル処理を酸化チタン微粉体に施したものも、シリカ系同様に好ましい。
【００９５】
本発明のトナーには、必要に応じてシリカ微粉体または、酸化チタン微粉体以外の添加剤を外添してもよい。例えば帯電補助剤、導電性付与剤、流動性付与剤、ケーキング防止剤、熱ロール定着時の離型剤、滑剤、研磨剤等の働きをする樹脂微粒子や無機微粒子である。
【００９６】
樹脂微粒子としては、その平均粒径が０．０３〜１．０μｍのものが好ましい。その樹脂を構成する重合性単量体としては、スチレン；ｏ−メチルスチレン，ｍ−メチルスチレン，ｐ−メチルスチレン，ｐ−メトキシスチレン，ｐ−エチルスチレン誘導体；アクリル酸；メタクリル酸；アクリル酸メチル，アクリル酸エチル，アクリル酸ｎ−ブチル，アクリル酸イソブチル，アクリル酸ｎ−プロピル，アクリル酸ｎ−オクチル，アクリル酸ドデシル，アクリル酸２−エチルヘキシル，アクリル酸ステアリル，アクリル酸２−クロルエチル，アクリル酸フェニルの如きアクリル酸エステル；メタクリル酸メチル，メタクリル酸エチル，メタクリル酸ｎ−プロピル，メタクリル酸ｎ−ブチル，メタクリル酸イソブチル，メタクリル酸ｎ−オクチル，メタクリル酸ドデシル，メタクリル酸２−エチルヘキシル，メタクリル酸ステアリル，メタクリル酸フェニル，メタクリル酸ジメチルアミノエチル，メタクリル酸ジエチルアミノエチルの如きメタクリル酸エステル；アクリロニトリル，メタクリロニトリル，アクリルアミド等の単量体が挙げられる。
【００９７】
重合法としては、懸濁重合、乳化重合、ソープフリー重合が挙げられる。より好ましくは、ソープフリー重合によって得られる粒子が良い。
【００９８】
その他の微粒子としては、弗素樹脂、ステアリン酸亜鉛、ポリ弗化ビニリデンの如き滑剤（中でもポリ弗化ビニリデンが好ましい）；酸化セリウム、炭化ケイ素、チタン酸ストロンチウムの如き研磨剤（中でもチタン酸ストロンチウムが好ましい）；酸化チタン、酸化アルミニウムの如き流動性付与剤（中でも特に疎水性のものが好ましい）；ケーキング防止剤；カーボンブラック、酸化亜鉛、酸化アンチモン、酸化スズの如き導電性付与剤が挙げられる。さらに、トナーと逆極性の白色微粒子及び黒色微粒子を現像性向上剤として少量用いても良い。
【００９９】
トナーと混合される樹脂微粒子または無機微粉体または疎水性無機微粉体は、トナー１００質量部に対して０．１〜５質量部（好ましくは、０．１〜３質量部）使用するのが良い。
【０１００】
トナーの重量平均粒径及び粒度分布はコールターカウンター法を用いて行うが、例えばコールターマルチサイザー（コールター社製）を用いることが可能である。電解液は１級塩化ナトリウムを用いて１％ＮａＣｌ水溶液を調製する。例えばＩＳＯＴＯＮ Ｒ−ＩＩ（コールターサイエンティフィックジャパン社製）が使用できる。測定法としては、前記電解水溶液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、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、２．００μｍ以上のトナー粒子の体積、個数を測定して体積分布と個数分布とを算出する。それから本発明に係る体積分布から求めた重量基準の重量平均粒径（Ｄ₄）を算出する。
【０１０１】
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チャンネルを用いる。
【０１０２】
本発明のトナーを製造する方法としては、上述したようなトナー構成材料をボールミルその他の混合機により十分混合した後、熱ロールニーダー、エクストルーダーの如き熱混練機を用いてよく混練し、冷却固化後、機械的に粉砕し、粉砕粉を分級することによってトナーを得る方法が好ましい。他には、結着樹脂を構成すべき単量体に所定の材料を混合して乳化懸濁液とした後に、重合させてトナーを得る重合法トナー製造法；コア材及びシェル材から成るいわゆるマイクロカプセルトナーにおいて、コア材あるいはシェル材、あるいはこれらの両方に所定の材料を含有させる方法；結着樹脂溶液中に構成材料を分散した後、噴霧乾燥することによりトナーを得る方法が挙げられる。更に必要に応じ所望の添加剤とトナー粒子とをヘンシェルミキサーの如き混合機により十分に混合し、本発明のトナーを製造することができる。
【０１０３】
例えば混合機としては、ヘンシェルミキサー（三井鉱山社製）；スーパーミキサー（カワタ社製）；リボコーン（大川原製作所社製）；ナウターミキサー、タービュライザー、サイクロミックス（ホソカワミクロン社製）；スパイラルピンミキサー（太平洋機工社製）；レーディゲミキサー（マツボー社製）が挙げられ、混練機としては、ＫＲＣニーダー（栗本鉄工所社製）；ブス・コ・ニーダー（Ｂｕｓｓ社製）；ＴＥＭ型押し出し機（東芝機械社製）；ＴＥＸ二軸混練機（日本製鋼所社製）；ＰＣＭ混練機（池貝鉄工所社製）；三本ロールミル、ミキシングロールミル、ニーダー（井上製作所社製）；ニーデックス（三井鉱山社製）；ＭＳ式加圧ニーダー、ニダールーダー（森山製作所社製）；バンバリーミキサー（神戸製鋼所社製）が挙げられ、粉砕機としては、カウンタージェットミル、ミクロンジェット、イノマイザ（ホソカワミクロン社製）；ＩＤＳ型ミル、ＰＪＭジェット粉砕機（日本ニューマチック工業社製）；クロスジェットミル（栗本鉄工所社製）；ウルマックス（日曹エンジニアリング社製）；ＳＫジェット・オー・ミル（セイシン企業社製）；クリプトロン（川崎重工業社製）；ターボミル（ターボ工業社製）が挙げられ、分級機としては、クラッシール、マイクロンクラッシファイアー、スペディッククラッシファイアー（セイシン企業社製）；ターボクラッシファイアー（日清エンジニアリング社製）；ミクロンセパレータ、ターボプレックス（ＡＴＰ）、ＴＳＰセパレータ（ホソカワミクロン社製）；エルボージェット（日鉄鉱業社製）、ディスパージョンセパレータ（日本ニューマチック工業社製）；ＹＭマイクロカット（安川商事社製）が挙げられ、造粒機としては、ローラーコンパクター（ターボ工業社製）が挙げられ、粗粒などをふるい分けるために用いられる篩い装置としては、ウルトラソニック（晃栄産業社製）；レゾナシーブ、ジャイロシフター（徳寿工作所社製）；バイブラソニックシステム（ダルトン社製）；ソニクリーン（新東工業社製）；ターボスクリーナー（ターボ工業社製）；ミクロシフター（槙野産業社製）；円形振動篩い等が挙げられる。
【０１０４】
次に本発明の画像形成方法及びプロセスカートリッジ（以下、「画像形成方法等」ともいう）について説明する。
【０１０５】
本発明の画像形成方法等は、以下の方法が挙げられる。本発明の画像形成方法等は、画像形成装置本体に着脱可能で、静電容量の変化により、逐次にトナー残量を検知できるトナー残量逐次検出手段を備えた画像形成方法等である。
【０１０６】
さらに、本発明の画像形成方法は、画像形成装置本体に着脱可能で、感光体に形成された静電潜像を現像するためにトナーを収容し、このトナーを前記感光体へ搬送するための現像剤担持体を備えたトナー収納部とを有するプロセスカートリッジにおいて、
前記現像剤担持体と対向し、間隔を置いて設置された上下二本の電極間（二本の電極のうち、どちらかが現像剤担持体もしくは現像ブレード板金であってもよい）の静電容量の変化を逐次に検知することによって、前記トナー収納部内のトナーの量を逐次に検知できるプロセスカートリッジを用いるものである画像形成方法等である。
【０１０７】
さらに、本発明の画像形成方法等は、画像形成装置本体に着脱可能で、感光体に形成された静電潜像を現像するためにトナーを収容し、このトナーを前記感光体へ搬送するための現像剤担持体を備えたトナー収納部とを有するプロセスカートリッジにおいて、
前記トナー収納部内のトナーの増減に伴い接触面積が変動する位置に配置された静電容量発生部の静電容量の変化を逐次に検知することにより、前記トナー収納部内のトナーの量を逐次に検知できるプロセスカートリッジを用いるものである画像形成方法等である。
【０１０８】
本発明に係る画像形成方法及びプロセスカートリッジを図面に則して更に詳しく説明する。なお、以下の説明ではプロセスカートリッジを装着する電子写真画像形成装置を用いるが、本発明の画像形成方法は、トナー収納部のトナー量を静電容量によって検出する機構を用いる画像形成方法であれば特に限定されず、静電記録方式やトナージェット方式等の他の画像形成方法にも適用することができる。
【０１０９】
＜プロセスカートリッジ形態１＞
先ず、図１を参照して、本発明に従って構成されるプロセスカートリッジを装着可能な電子写真画像形成装置の一実施形態について説明する。本実施形態にて、電子写真画像形成装置は、電子写真式のレーザービームプリンタＡとされ、電子写真画像形成プロセスによって記録媒体、例えば、記録紙、ＯＨＰシート、布などに画像を形成するものである。
【０１１０】
レーザービームプリンタＡは、ドラム形状の電子写真感光体、即ち、感光体ドラム７を有する。感光体ドラム７は、帯電手段である帯電ローラ８によって帯電され、次いで、レーザダイオード１ａ、ポリゴンミラー１ｂ、レンズｌｃ、反射ミラー１ｄを有した光学手段１から画像情報に応じたレーザ光を照射することによって、感光体ドラム７に画像情報に応じた潜像が形成される。この潜像は、現像手段９によって現像され、可視像、即ち、トナー像とされる。
【０１１１】
図２に示すように、現像手段９は、現像剤担持体としての現像ローラ９ａを備えた現像室９Ａを有しており、現像室９Ａに隣接して形成されたトナー収納部としてのトナー容器１１Ａ内の現像剤をトナー送り部材９ｂの回転によって、現像室９Ａの現像ローラ９ａへと送り出す。現像室９Ａには、現像ローラ９ａの近傍に現像剤撹拌部材９ｅを備えており、現像室内のトナーを循環させる。また、現像ローラ９ａは、固定磁石９ｃを内蔵しており、現像ローラ９ａを回転することによってトナーは搬送され、現像ブレード９ｄにて摩擦帯電電荷が付与されると共に所定厚のトナー層とされ、感光体ドラム７の現像領域へと供給される。この現像領域へと供給されたトナーは、前記感光体ドラム７上の潜像へと転移され、トナー像を形成する。現像ローラ９ａは、現像バイアス回路に接続されており、通常、交流電圧に直流電圧が重畳された現像バイアス電圧が印加される。
【０１１２】
一方、トナー像の形成と同期して給紙カセット３ａにセットした記録媒体２をピックアップローラ３ｂ、搬送ローラ対３ｃ、３ｄ及びレジストローラ対３ｅで転写位置へと搬送する。転写位置には、転写手段としての転写ローラ４が配置されており、電圧を印加することによって、感光体ドラム７上のトナー像を記録媒体２に転写する。
【０１１３】
トナー像の転写を受けた記録媒体２は、搬送ガイド３ｆで定着手段５へと搬送する。定着手段５は、駆動ローラ５ｃ及びヒータ５ａを内蔵した定着ローラ５ｂを備え、通過する記録媒体２に熱及び圧力を印加して転写されたトナー像を記録媒体２上に定着する。
【０１１４】
記録媒体は、排出ローラ対３ｇ、３ｈ、３ｉで搬送し、反転経路３ｊを経由して排出トレイ６へと排出される。この排出トレイ６は、レーザービームプリンタＡの電子写真画像形成装置本体１４の上面に設けられている。なお、揺動可能なフラッパ３ｋを動作させ、排出ローラ対３ｍによって反転経路３ｊを介することなく記録媒体２を排出することもできる。本実施形態では、上記ピックアップローラ３ｂ、搬送ローラ対３ｃ、３ｄ、レジストローラ対３ｅ、搬送ガイド３ｆ、排出ローラ対３ｇ、３ｈ、３ｉ及び排出ローラ対３ｍによって搬送手段３を構成している。
【０１１５】
転写ローラ４によってトナー像を記録媒体２に転写した後の感光体ドラム７は、クリーニング手段１０によって感光体ドラム７上に残留したトナーを除去した後、次の画像形成プロセスに供される。クリーニング手段１０は、感光体ドラム７に当接して設けられた弾性クリーニングブレード１０ａによって感光体ドラム７上の残留現像剤を掻き落として廃トナー溜め１０ｂへと集める。
【０１１６】
次に、本実施形態のプロセスカートリッジＢの一例を説明する。図２に示すように、トナーを収納するトナー容器（トナー収納部）１１Ａ及び、トナー撹拌手段であるトナー撹拌・搬送部材９ｂを有する枠体１１と、現像ローラ９ａ及び現像ブレード９ｄなどの現像手段９を保持する現像枠体１２とを溶着して一体として現像装置が形成される。プロセスカートリッジＢは、該現像装置に、感光体ドラム７、クリーニングブレード１０ａなどのクリーニング手段１０及び帯電ローラ８を取り付けたクリーニング枠体１３を一体に結合することによってカートリッジ化されている。
【０１１７】
本発明によれば、プロセスカートリッジＢは、トナー容器１１Ａ内のトナーの消費に従ってその残量を逐次検出することのできるトナー量検出手段（以下、「トナー量検出装置」ともいう）を備えている。
【０１１８】
プロセスカートリッジ形態によれば、トナー量検出装置は、図３に示すように、トナー撹拌・搬送部材９ｂによって送られたトナーが入り込めるような、下方が開放された凹部８０を形成する第１及び第２の電極８１、８２等の検知手段（以下、トナー量検出手段に用いる電極を「検知手段」ということもある）を用いる。
【０１１９】
また、これらの電極８１、８２は、略対向し且つ現像ローラ９ａとほぼ平行になるように配置されている。つまり、現像剤撹拌・搬送部材（撹拌部材）９ｂによって移動させられるトナーＴの移動方向と交差する方向において、第１電極８１と第２電極８２は異なった位置に配置されている。尚、第１、第２電極８１、８２は現像室９を構成する枠体１２に取り付けられている。これら電極８１、８２のより具体的な構成については、後で詳しく説明する。
【０１２０】
そして、トナー量検出装置は、第１及び第２の電極８１、８２のいずれかに交流電圧を印加することにより、これらの電極８１、８２間の静電容量に応じた電気信号を発生させ、それを測定することでトナー量を検出するものである。
【０１２１】
次に、プロセスカートリッジの出荷前から、電子写真画像形成装置本体１４に装着され、使用される際におけるトナーの動きと減少状態について説明する。
【０１２２】
プロセスカートリッジを出荷する際には、図３において点線で示すように、現像室９Ａとトナー容器１１との間に、トナー容器１１内のトナーを密封するためのシール部材３０を貼設し、搬送時の振動などによってトナーが外部に漏れないようにしている。
【０１２３】
ユーザーがプロセスカートリッジを使用する際には、シール部材３０を取り除いたうえで電子写真画像形成装置本体１４に装着する。尚、近年では、電子写真画像形成装置本体１４に装着した後、自動的にシール部材３０を取り除く構成を備えたものもある。
【０１２４】
上記のように、トナー容器１１内にはトナー撹拌・搬送部材９ｂが設けられているが、このトナー撹拌・搬送部材９ｂは撹拌軸９ｂ１と、撹拌軸９ｂに取り付けられた弾性シート（マイラー）９ｂ２とを備えており、その回転によってトナー容器１１内のトナーを現像室９Ａ側へと搬送する。
【０１２５】
このトナー撹拌・搬送部材９ｂの作用によって、プロセスカートリッジＢが初めて使用され、シール部材３０が取り除かれた直後であっても、トナーは即座に現像室９Ａ側に送り込まれるため、スムーズに印字可能状態となる。同時に、第１、第２電極８１、８２間にもトナーが送り込まれるため、静電容量が変化する。
【０１２６】
第１、第２電極８１、８２近傍に分布するトナーの状態を変化する力としては以下の４項目が挙げられる。
（１）トナー撹拌・搬送部材９ｂによって送り込まれる際の上方向の力。
（２）トナーの自重にて下方に落下する力。
（３）凹部８０内のトナーに蓋をし、留めようとする力。（凹部８０の下方にトナーが多量に存在すると、「自重によって落下しようとするトナー」に蓋をしてしまう。）
（４）トナー自体の流動性が低いために現状位置に留まろうとする力。
【０１２７】
トナー容器１１内及び現像室９Ａ内にトナーが十分にある時には、項目（１）の力が極めて大きく、また、項目（３）の力によって凹部８０が蓋する力によってしっかりと締められているため、第１、第２電極８１、８２間にはトナーが詰め込まれた状態が維持され、この場合、静電容量値として高い値を示し続ける。
【０１２８】
プロセスカートリッジＢを使用し続けると、現像ローラ９ａ近傍のトナーは現像のために消費されて減少するが、トナー撹拌・搬送部材９ｂの作用によって現像ローラ９ａ近傍にはトナー容器１１内のトナーが常に補充される。その結果、プロセスカートリッジＢを使用していくと、トナー容器１１内のトナーの量が減少し、その高さは低くなっていく。
【０１２９】
図４に示すように、図４（ａ）、（ｂ）、（ｃ）、（ｄ）の順にトナー容器１１内のトナーの高さが低くなっていくと、上記項目（１）と（３）の力が小さくなり、そのため次第に第１、第２電極８１、８２間のトナー残量も減少していき、その結果、静電容量も変化する。
【０１３０】
図４について説明すると、図４（ａ）にはトナーがトナー容器１１内に十分にあって第１、第２電極８１、８２がトナー中に埋まっている状態が示されている。図４（ｂ）にはトナー容器１１内のトナーが減少し、トナーの表面が第１電極８１の下端と第２電極８２の上端に接する高さになっている状態が示されている。図４（ｃ）にはトナーが更に減少し、既に凹部８０内にはなく、第１電極８１の下端よりも低く、第２電極８２の中程の高さになっている状態が示されている。図４（ｄ）には第２電極８２の下端にようやく接する程度の高さになっている状態が示されている。
【０１３１】
トナー容器１１内のトナー高さ（トナー残量）と静電容量値の変化の傾向は、使用しているトナーの流動性やトナー撹拌・搬送部材９ｂの搬送能力によって左右される。
【０１３２】
例えば、トナーが水のような流動性を有している場合、トナー容器１１内のトナー高さと第１、第２電極８１、８２間のトナー高さは完全に一致するが、実際のトナーの流動性は水の流動性に比べてはるかに低く、トナー撹拌・搬送部材９ｂによって現像室９Ａ側に搬送された状態をある程度維持するため、図４（ａ）乃至（ｄ）に示したように、トナー容器１１内のトナー高さの変化に若干遅れて第１、第２電極８１、８２間のトナー高さが変化する傾向がある。
【０１３３】
また、トナー撹拌・搬送部材９ｂの搬送力が弱すぎても強すぎても、第１、第２電極８１、８２間へのトナーの入り込みが変わり、トナー残量の変化と静電容量値の変化との関係が異なったものとなる。
【０１３４】
従って、トナーの流動性及びトナー搬送能力に応じて第１、第２電極の位置や形状を適正化する必要がある。
【０１３５】
上記構成以外に、例えばプロセスカートリッジに記憶手段を備えている場合は印字枚数やプロセスカートリッジの駆動時間などを記憶させておき、平衡状態に達すると考えられる時間以上を経過した時に初めて検出をスタートする方法もある。
【０１３６】
また、トナー量を逐次に検出する際に、検出精度を向上させるためには、静電容量の変化量を増やせばよい。これは、具体的には第１、第２電極８１、８２のそれぞれの表面積を増やすこと、あるいは第１、第２電極８１、８２間の距離を近づけることなどによって達成できる。電極の表面積を増やす際には、図５に示すように、波打ち形状にしてもよく、あるいは図６に示すように、絞り形状にしてもよい。
【０１３７】
尚、設計上の都合により、電極のスペースが確保できない、あるいはコストダウンを図らなければならないというときには、図７及び図８に示すように、第１、第２電極８１、８２のいずれか一方を丸棒などによって構成してもよい。
【０１３８】
画像形成を続けることによって、トナーの消費が進み、最終的に、現像ローラ９ａ表面のトナー量を規制する現像ブレード９ｄの先端と第２電極８２の間、即ち、現像ローラ９ａと第２電極８２の間のトナーが消費されることで画像上に白抜けが発生し、トナーエンド、つまりトナー無しの状態になる。
【０１３９】
このとき更に現像ローラ９ａや現像ブレードの板金をコンデンサの電極の一つとして用い（対となるのは第２電極８２である）、図９に示すように、第１、第２電極８１、８２が構成するコンデンサと並列に接続することによって白抜けの検出精度を大幅に向上させることができる。
【０１４０】
図１０のグラフに、現像ローラ９ａをコンデンサーの一つとして用いた場合（図１０（ｂ））と、用いない場合（図１０（ａ））とについての検出精度を模式的に示す。図１０（ｂ）の方が、図１０（ａ）に比して、白抜け間際の単位トナー変化量（消費量）に対する静電容量の変化量が劇的に大きくなっていることが分かる。
【０１４１】
白抜け間際の単位トナー変化量（消費量）に対する静電容量の変化量が劇的に大きくなるのは、上述のように白抜けが現像ローラ９ａ表面上のトナー量が減り始めることによって発生するからであり、従って、現像ローラ９ａ表面上のトナー量をより正確に測定することが検出精度アップの必須条件となる。
【０１４２】
上記のように、現像ローラ９ａをコンデンサの電極の一つとして用い、対となる第２電極８２が現像ローラ９ａ表面の近傍にあることによって、現像ローラ９ａ近傍における「検出感度」を高くすることが可能となり、図１０（ａ）、（ｂ）における検出精度の差が生じることとなる。
【０１４３】
更に白抜け近傍の「検出感度」を高めるためには、現像ローラ９ａ表面近傍における「検出感度」を高める必要がある。
【０１４４】
現像ローラ９ａ表面上にトナーがほとんどなくても、図１１に示すように、現像ブレード９ｄ近傍領域にトナーＴがあると現像が可能となることから、上記領域におけるトナーＴを感度良く検出することによって白抜け検出精度を向上させることができる。
【０１４５】
しかしながら、本発明のプロセスカートリッジ形態１のように長手方向に電極を配置させることによって、二本の電極間（もしくは電極と現像スリーブ・ブレード間）でのトナーの詰りという現象も起こりやすくなってしまう。
本発明の如きトナーを用いることによって、電極へのトナー付着を防止でき、両電極間の詰りも発生しないために、良好なトナー残量検知精度が得られるようになる。
【０１４６】
尚、上記の電極８１、８２は導電性部材であれば、すべて同等の作用をするが、本発明のプロセスカートリッジ形態では、トナーの循環に影響を出さないように、非磁性ＳＵＳ材などの非磁性金属材料を用いている。
【０１４７】
また、電極８１、８２を、現像室９Ａを構成する枠体１２に直接、蒸着、印刷などの処理を施したり、導電性樹脂を２色成形すれば、別部材からなる電極に比べ、取り付け公差、部品公差がへるため、位置精度の向上を図ることができる。
【０１４８】
上記説明では、トナーとして磁性トナーを用いたトナー量検出の構成について説明したが、非磁性トナーを用いた現像装置構成にも適用できる。
【０１４９】
＜プロセスカートリッジ形態２＞
次に、本発明の第２のプロセスカートリッジ形態について図１２〜図１４により説明する。
【０１５０】
第２のプロセスカートリッジ形態においても、第１のプロセスカートリッジ形態において説明したものと同様の構成及び作用をなす電子写真画像形成装置を用い、同一部材については同一符号を付す。
【０１５１】
第２のプロセスカートリッジ形態では、図１２に示すように電極８４を現像室９Ａの底面に配置している。即ち、電極８４は、トナー容器１１に収納されているトナーＴが現像ローラ９ａへ至る経路に沿って設けられている。従ってこの電極８４は以下、経路電極８４という。この経路電極８４は、図１２に示す断面形状で長手方向全領域について同じ形状をしている。
【０１５２】
現像室９Ａの底面近傍の磁性トナーは現像ローラ９ａの中に配置されたマグネット９ｃの磁力によって現像ローラ９ａに引き付けられる力が常に働いている。そのためトナー量が少なくなりトナー容器１１からのトナーの供給が減少すると、まず現像室９Ａの床面近傍のトナーから消費されていく傾向がある。
【０１５３】
具体的には、図１３に示すように、トナー容器１１内のトナー残量が多いと現像室９Ａ内のトナーを自重で押し込むため上記のようにトナーが消費されてもすぐに押し込まれるが（図１３（ａ））、トナー容器１１内のトナー残量が少なくなっていくと、消費されたトナーの分を押し込む力が強く働かずに、現像室９Ａの底面近傍から空洞ができて（図１３（ｂ）、（ｃ））、最終的には現像ブレード９ｄ先端周りにトナーが残るようになる（図１３（ｄ））。
【０１５４】
このようにトナーが消費されていくので、本構成によれば、現像室９Ａの底面近傍のトナー量を検出できるトナー量検出が可能となる。
【０１５５】
図１４のグラフに、トナー残量が減少していく時の静電容量の変化を模式的に示す。図１４に示すように、本構成を用いてもトナー量検出が可能であることが分かる。
【０１５６】
このようなカートリッジ形態の場合には、トナー容器底面や側面へのトナーの付着、特にトナー残量検出手段付近での付着により、トナー残量検知精度が落ちるようになることがあるが、本発明のトナーによれば、トナー容器の底面・側面への付着が防止されるために、良好なトナー残量検知精度が得られる。
【０１５７】
＜プロセスカートリッジ形態３＞
次に、本発明の第３のプロセスカートリッジ形態について説明する。
【０１５８】
第３のプロセスカートリッジ形態においては、トナー量検出装置は、図１５に示すように、トナー量を検知する第一静電容量発生部としての測定電極部材２０Ａを有する。このとき、環境、即ち、雰囲気の温度・湿度を検知し、基準用信号を出力する比較部材である第二静電容量発生部としての基準電極部材２０Ｂを有することが好ましい。
【０１５９】
測定電極部材２０Ａは、図１５に示すように、現像手段９のトナー容器１１Ａの内部側面、また、は、図１６に示すように、トナー容器１１Ａの内部底面などの、トナーと接触する位置であって、しかも、トナーが減少するに従って、トナーとの接触面積が変動するような方向に配置される。また、基準電極部材２０Ｂを設置する場合は、図１５に示すように、トナーと接触することのない装置本体１４の任意の場所に設置することも可能であるが、例えば、図１７に示すように、トナー容器１１Ａの内部であって、測定電極部材２０Ａとは反対側位置に仕切壁２１にて区画された、トナーとは接触しない箇所に設けることもできる。更に、図１８に示すように、測定電極部材２０Ａと基準電極部材２０Ｂとを対称配置にて一体的に作製した場合には、基準電極部材２０Ｂを外方へと折り曲げて、測定電極部材２０Ａが配置されたと同じ側のトナー容器内であって、仕切壁２１にて区画された、トナーとは接触しない箇所に設けることもできる。
【０１６０】
測定電極部材２０Ａは、図１９に示すように、基板２２の上に所定の間隔をもって平行に形成された一対の導電部、即ち、電極２３、２４を有する。各電極２３、２４は、一つの基部と、この基部から分岐した複数個の分岐部を有することができ、各電極２３、２４の分岐部は、一定の間隔で交互に平行に並んで形成することができる。本実施形態では、電極２３、２４は、所定間隔Ｇにて平行に並置された少なくとも一対の電極部分２３ａ〜２３ｆ、２４ａ〜２４ｆを有し、各電極部分２３ａ〜２３ｆ、２４ａ〜２４ｆは、連結電極部分２３ｇ、２４ｇにて互いに連結されており、二つの電極２３及び２４は、その分岐部が互いに組み合わさった多数の凹凸形状とされている。勿論、測定電極部材２０の電極パターンは、これに限定されるものではなく、図２０に示すように一対の電極２３、２４を互いに所定の間隔にて平行に配置された渦巻き形状に形成することもできる。
【０１６１】
測定電極部材２０Ａは、一対の平行電極２３、２４間の静電容量を測定することによりトナー容器１１Ａ内のトナー残量を逐次検知することができる。つまり、トナーは空気より誘電率が大きいために測定電極部材２０Ａの表面にトナーが接触することにより―対の電極２３、２４間の静電容量が増加する。
【０１６２】
従って、本発明によれば、上記構成の測定電極部材２０Ａを用いることにより、測定電極部材２０Ａの表面に接するトナーの面積から所定の較正曲線を適用することによりトナー容器１１Ａの断面形状や測定電極部材２０Ａの形状によらずトナー容器１１Ａ内のトナー量を測定することができる。
【０１６３】
斯かる測定電極部材２０Ａの電極パターン２３、２４は、例えば厚さ０．４〜１．６ｍｍの、例えば紙フェノール、ガラスエポキシ等の硬質プリント基板２２、または厚さ０．１ｍｍ程度のポリエステル、ポリイミド等の可撓性のプリント基板２２上にエッチング或いは印刷にて銅などの導体金属パターン２３、２４を形成することによって得ることができ、通常のプリント基板の配線パターン形成方法と同一の方法で製造することができる。従って、図１９及び図２０に示すような複雑な電極パターン形状であっても容易に製造することができ、製造コストも簡単なパターンのものと殆ど変わりはない。
【０１６４】
また、図１９及び図２０に示すような複雑なパターン形状を用いることにより、電極２３、２４間の対向長さを長くでき、更にエッチングなどのパターン形成方法を用いることにより電極２３、２４間の所定間隔Ｇを数十μｍ程度まで狭くすることも可能であり、大きな静電容量を得ることが可能となる。また、静電容量の変化量を大きくすることができ、検知精度を上げることができる。具体的には、電極２３、２４は、幅０．１〜０．５ｍｍ、厚さ１７．５〜７０μｍとされ、間隔Ｇは０．１〜０．５ｍｍとされる。更に、金属パターン形成面は、例えば１２．５〜１２５μｍ程度の薄い樹脂フィルムにてラミネートすることも可能である。
【０１６５】
上述のように、本発明のトナー量検出装置によれば、トナー容器１１Ａの内部の側面または底面の現像剤が減少する方向に設置された測定電極部材２０Ａに対するトナーの接触面積の変化、即ち、測定電極部材２０Ａの静電容量の変化を測定し、その値によりトナー容器全体のトナー量を逐次に検出する。
【０１６６】
つまり、トナーの誘電率は空気より大きいため、測定電極部材２０Ａに現像剤が接触している部分（トナーが有る部分）は、接触していない部分（トナーが無い部分）に比べて出力される静電容量が大きい。従って、その静電容量の変化を測定すればトナー容器１１Ａ内の現像剤量を推定できる。
【０１６７】
図１５に示すように、測定電極部材２０Ａをトナー容器１１Ａの片側の内側面に配置することにより、トナー容器長手方向側部の、図２１に示すＹＺ平面の断面積に占めるトナーの割合を静電容量の値により推測することが可能である。
【０１６８】
更に、図２２に示すように測定電極部材２０Ａを現像剤容器内側の両側面の二箇所に配置することにより、図２３に示すようにジャム処理などでプロセスカートリッジＢを着脱したときに、または、プロセスカートリッジＢを傾けたり、印字パターンの偏りなどによって、長手方向に極端にトナーが偏った場合でも、両電極部材２０Ａ、２０Ａの出力を比較することにより、トナーの偏りを推測することが可能であり、片側に配置した場合よりも長手方向のトナーの偏りに対してトナー残量を正確に推測することが可能になる。但し、本発明のトナーを用い、更にはトナー容器内に撹拌機構を備えている場合は、二箇所に配置することは必ずしも必要ではない。
【０１６９】
また、図１６に示すように、測定電極２０Ａをトナー容器１１Ａ内側の底面に配置した場合は、底面積にトナーの占める割合を推測することが可能なため、長手方向のトナーの偏りの影響を小さくできる。更に、トナー容器１１Ａは側面の面積より底面の面積の方が広いため、前述の側面に配置した場合に比べてトナー量検出部材２０Ａの設置面積を大きくすることが可能となり、静電容量の変化量を大きくでき、出力を大きくとることができるため測定誤差を小さくすることができる。
【０１７０】
トナー容器１１Ａ内側の底面と側面に電極部材を配置した場合は、トナー容器１１Ａ内のトナー量を三次元的に推測することが可能であるため、より正確にトナー容器内のトナー量を検知することができる。
【０１７１】
本発明によれば、トナー残量検出装置は、図１５に示すように、更に、第二静電容量発生部としての基準電極部材２０Ｂを有してもよい。
【０１７２】
基準電極部材２０Ｂは、上記測定電極部材２０Ａと同様の構成とされ、図１９に示すように、基板２２の上に所定の間隔Ｇをもって平行に形成された一対の導電部、即ち、電極２３（２３ａ〜２３ｆ）、２４（２４ａ〜２４ｆ）を有し、二つの電極２３及び２４の分岐部が互いに組み合わさった多数の凹凸形状とすることもできるし、また、図２０に示すように渦巻き形状に形成することもできる。基準電極部材２０Ｂもまた、通常のプリント基板の配線パターン形成方法と同一の方法で製造し得る。
【０１７３】
本発明によれば、基準電極部材２０Ｂは、上述したように、温度、湿度などの環境条件によって静電容量が変動し、測定電極部材２０Ａに対して基準用の比較部材として機能するため、トナー残量検知の精度を高めることができる。
【０１７４】
このようなプロセスカートリッジ形態の場合には、トナー残量検出手段が側面もしくは底面に面状の静電容量発生部として設置されているが、そのような部分へはトナーの付着が起こり易くなり、特に基板上の電極間にトナーが付着することによって静電容量が変化してしまい、精度の高いトナー残量検出ができなくなることがあるが、本発明のトナーによれば、付着性が抑えられているためにそのような不具合を発生することなく、高精度なトナー残量検知が達成できる。
【０１７５】
尚、上述したプロセスカートリッジ形態において、当初、容器内に収納されているトナーの量を１００％としたときに、トナーの残量を約３０％乃至０％までの全領域にわたって逐次に検出することができる。しかしながら、本発明はこれに限定されるものではなく、例えば、容器内のトナーの残量が５０％乃至０％まで、或いは、４０％乃至０％までの領域にわたって逐次に検出するようにしてもよい。ここで、「トナーの残量が０％」とは、トナーが完全になくなったことのみを意味するものではない。例えば、トナーの残量が０％とは、容器内にトナーが残っていたとしても、所定の画像品質（現像品質）が得られなくなる程度までトナーの残量が減ったことも含まれる。
【０１７６】
【実施例】
以下、具体的実施例によって本発明を説明するが、本発明は何らこれに限定されるものではない。
【０１７７】
−樹脂製造例−
（高分子量重合体の合成例）
高分子量重合体（Ｈ−１）の合成：
４ツ口フラスコに脱気水１８０質量部とポリビニルアルコールの２質量％水溶液２０質量部を投入した後、スチレン７０質量部、アクリル酸−ｎ−ブチル２０質量部、マレイン酸モノブチル１０質量部、ジビニルベンゼン０．００１質量部、及び、２，２−ビス（４，４−ジ−ｔｅｒｔ−ブチルパーオキシシクロヘキシル）プロパン（半減期１０時間温度９２℃）０．１質量部の溶液の混合液を加え、撹拌し懸濁液とした。
【０１７８】
フラスコ内を充分に窒素で置換した後、８５℃まで昇温して、重合を開始した。同温度に２４時間保持した後、ベンゾイルパーオキサイド（半減期１０時間温度９２℃）０．１質量部を追加添加した。さらに、１２時間保持して重合を完了した。これを瀘別し、水洗、乾燥し、高分子量重合体（Ｈ−１）を得た。
【０１７９】
該高分子量重合体（Ｈ−１）を瀘別し、水洗、乾燥した後、分析したところ、Ｍｗ＝９０万、ＰＭｗ＝８３万、Ｍｗ／Ｍｎ＝２．３、Ｔｇ＝６２℃であった。
【０１８０】
高分子量重合体（Ｈ−２）の合成：
４ツ口フラスコ内にキシレン３００質量部を投入し、撹拌しながら容器内を充分に窒素で置換した後、昇温して還流させる。
【０１８１】
この還流下で、スチレン６５質量部、アクリル酸−ｎ−ブチル３０質量部、マレイン酸モノブチル５質量部、ジビニルベンゼン０．００１質量部、及び、ジ−ｔｅｒｔ−ブチルパーオキサイド０．５質量部の混合液を４時間かけて滴下後、２時間保持し重合を完了し、高分子量重合体（Ｈ−２）溶液を得た。
【０１８２】
この重合体溶液の一部をサンプリングし、減圧下で乾燥させ、得られた高分子量重合体（Ｈ−２）を分析したところ、Ｍｗ＝２３万、ＰＭｗ＝１２万、Ｍｗ／Ｍｎ＝２．９、Ｔｇ＝５５℃であった。
【０１８３】
（低分子量重合体の合成例）
低分子量重合体（Ｌ−１）の合成：
４ツ口フラスコ内にキシレン３００質量部を投入し、撹拌しながら容器内を充分に窒素で置換した後、昇温して還流させる。
【０１８４】
この還流下で、スチレン９３質量部、アクリル酸−ｎ−ブチル７質量部、及び、ジ−ｔｅｒｔ−ブチルパーオキサイド３質量部の混合液を４時間かけて滴下後、２時間保持し重合を完了し、低分子量重合体（Ｌ−１）溶液を得た。
【０１８５】
この重合体溶液の一部をサンプリングし、減圧下で乾燥させ、得られた低分子量重合体（Ｌ−１）の分析を行なったところ、Ｍｗ＝９８００、ＰＭｗ＝８０００、Ｍｗ／Ｍｎ＝２．３、Ｔｇ＝６１．２℃であった。
【０１８６】
低分子量重合体（Ｌ−２）の合成：
スチレン９６質量部、アクリル酸−ｎ−ブチル４質量部、及び、ジ−ｔｅｒｔ−ブチルパーオキサイド５質量部とした以外は、低分子量重合体（Ｌ−１）と同様に重合を行い、低分子量重合体（Ｌ−２）溶液を得た。
【０１８７】
この重合体溶液の一部をサンプリングし、減圧下で乾燥させ、得られた低分子量重合体（Ｌ−３）の分析を行なったところ、Ｍｗ＝６９００、ＰＭｗ＝５９００、Ｍｗ／Ｍｎ＝２．１、Ｔｇ＝５９．３℃であった。
【０１８８】
低分子量重合体（Ｌ−３）の合成：
スチレン１００質量部、及び、ジ−ｔｅｒｔ−ブチルパーオキサイド９質量部とした以外は、低分子量重合体（Ｌ−１）と同様に重合を行い、低分子量重合体（Ｌ−２）溶液を得た。
【０１８９】
この重合体溶液の一部をサンプリングし、減圧下で乾燥させ、得られた低分子量重合体（Ｌ−２）の分析を行なったところ、Ｍｗ＝４３００、ＰＭｗ＝４０００、Ｍｗ／Ｍｎ＝２．４、Ｔｇ＝６０℃であった。
【０１９０】
低分子量重合体（Ｌ−４）の合成：
スチレン８６質量部、アクリル酸−ｎ−ブチル１４質量部、及び、ジ−ｔｅｒｔ−ブチルパーオキサイド２質量部とした以外は、低分子量重合体（Ｌ−１）と同様に重合を行い、低分子量重合体（Ｌ−４）溶液を得た。
【０１９１】
この重合体溶液の一部をサンプリングし、減圧下で乾燥させ、得られた低分子量重合体（Ｌ−４）の分析を行なったところ、Ｍｗ＝２０３００、ＰＭｗ＝１８０００、Ｍｗ／Ｍｎ＝２．３、Ｔｇ＝６７．６℃であった。
【０１９２】
低分子量重合体（Ｌ−５）の合成：
スチレン７５質量部、アクリル酸−ｎ−ブチル２５質量部、及び、ジ−ｔｅｒｔ−ブチルパーオキサイド１．５質量部とした以外は、低分子量重合体（Ｌ−１）と同様に重合を行い、低分子量重合体（Ｌ−５）溶液を得た。
【０１９３】
この重合体溶液の一部をサンプリングし、減圧下で乾燥させ、得られた低分子量重合体（Ｌ−５）の分析を行なったところ、Ｍｗ＝３７０００、ＰＭｗ＝３０２００、Ｍｗ／Ｍｎ＝２．３、Ｔｇ＝５１．１℃であった。
【０１９４】
次に、表１に示すような割合で高分子量重合体と低分子量重合体を混合した。方法は、キシレン１００質量部に、高分子量重合体と低分子量重合体の合計が１００質量部となるようにして投入し、昇温して還流下で撹拌し、１２時間保持した後、有機溶剤を留去し、得られた樹脂を冷却、固化後、粉砕してトナー用樹脂組成物を得た。
【０１９５】
＜実施例１＞
樹脂成分とワックス成分を表１に示した処方とし、下記の如くしてトナーを得た。
【０１９６】
・表１に示したトナー用樹脂組成物 １００質量部
・球形磁性酸化鉄(平均粒径０．２０μｍ・ＢＥＴ８．５ｍ²／ｇ)１００質量部
・モノアゾ鉄錯体 ２質量部
・ポリプロピレン（ＤＳＣ吸熱ピーク１４０℃） ３質量部
上記混合物をヘンシェルミキサーで前混合した後、１３０℃に加熱された２軸エクストルーダで溶融混練し、冷却した混練物をハンマーミルで粗粉砕し、ジェット気流を用いた粉砕機（ジェットミル）によって微粉砕し、得られた微粉砕物をコアンダ効果を利用した多分割分級装置（日鉄鉱業社製エルボジェット分級機）で微粉、超微粉及び粗粉を同時に厳密に分級除去して、重量平均粒径（Ｄ₄）６．７μｍの負帯電性トナー粒子を得た。
【０１９７】
この磁性トナー粒子１００部と、ジメチルジクロロシラン処理した後、ヘキサメチルジシラザン処理し、次いでジメチルシリコーンオイル処理を行った疎水性シリカ微粉体１．２部とを、ヘンシェルミキサーで混合して負帯電性トナー１を調製した。このトナーの分析結果を表１に示した。
【０１９８】
＜実施例２〜４、参考例１、比較例１〜３＞
実施例１と同様にして、表１のトナー処方に基づき、実施例２〜４、参考例１、及び、比較例１〜３のトナーを得た。これらのトナーの分析結果を表１に示した。
【０１９９】
次に、調製されたトナーを以下に示すような方法によって評価した。評価結果を表２に示す。
【０２００】
プロセスカートリッジ形態１に示した、逐次にトナー残量を検知可能なトナー残量検出手段を装着したＥＰ−７２カートリッジを、上記トナーが１６００ｇ充填できるように改造した。また、キヤノン製レーザービームプリンターＬＢＰ−９５０を前記カートリッジが入り、トナー残量検知信号が検出可能なように改造し、更にＡ４横送りで３２枚／分から５０枚／分に改造し、更に定着器の加熱ローラーと加圧ローラー間の総圧を３３３Ｎ（３４ｋｇ）、ニップを９ｍｍに設定した。この時のプロセススピードは２３５ｍｍ／ｓｅｃであった。
【０２０１】
以上の設定条件で高温高湿環境下（３０℃，８５％ＲＨ）及び低温低湿環境下（１５℃，１０％ＲＨ）において２枚／６ｓｅｃ．の間欠プリント速度で３００００枚の画出し試験を行い、得られた画像を下記の項目について評価した。また、高温高湿環境下においては、１５０００枚の画出し試験の後、同一環境下において２日間放置し、更に１５０００枚の画出し試験を行った。
【０２０２】
（１）画像濃度
通常の複写機用普通紙（７５ｇ／ｍ²）に３００００枚プリントアウトし、高温高湿環境下（温度３０℃，湿度８５％ＲＨ）では２日間の放置後の朝一及び耐久終期の画像濃度、低温低湿環境下（温度１５℃，湿度１０％ＲＨ）では耐久終期の画像濃度の評価を行った。なお、画像濃度は「マクベス反射濃度計」（マクベス社製）を用いて、原稿濃度が０．００の白地部分のプリントアウト画像に対する相対濃度を測定した。
【０２０３】
（２）カブリ
通常の複写機用普通紙（７５ｇ／ｍ²）に、低温低湿下（温度１５℃，湿度１０％ＲＨ）で３００００枚プリントアウトし、開始時及び終了時のカブリの評価を行った。リフレクトメーター（東京電色（株）製）により測定した転写紙の白色度と、ベタ白をプリント後の転写紙の白色度との比較からカブリを算出した。
【０２０４】
（３）トナー残量検出精度
通常の複写機用普通紙（７５ｇ／ｍ²）に、高温高湿環境下（３０℃、８５％ＲＨ）で連続プリントアウトし、トナー残量１０％検知（１６５ｇに相当）、及び、５％検知（８２．５ｇに相当）時点でのトナー残量を実測し、残量検知装置による出力信号の値と比較することによって、残量検知誤差を求めた。
残量検知誤差（％）＝｛｜（実測残量）−（残量検知値）｜／（実測残量）｝×１００
【０２０５】
（４）画像品質
通常環境（２３℃，６０％ＲＨ）において、図２４に示すチェッカー模様をプリントアウトし、ドット再現性を以下の評価基準に基づいて評価した。
（評価基準）
◎：非常に良好（欠損２個以下／１００個）
○：良好（欠損３〜５個／１００個）
△：普通（欠損６〜１０個／１００個）
×：悪い（欠損１１個以上／１００個）
【０２０６】
（５）フェーディング
高温高湿（３０℃，８５％ＲＨ）環境下において、１０００枚ごとにベタ黒画像をとりながら、４％印字パターンを２枚／６秒の割合で間欠的に３００００枚耐久画出しし、ベタ黒画像の均一性により、フェーディングの有無をチェックした。
【０２０７】
【表１】

【０２０８】
【表２】

【０２０９】
【発明の効果】
高温高湿、低温低湿のような厳しい環境下においても長期の使用において高い現像性を維持し、精密な逐次トナー残量検知を行い、且つ、フェーディング現象等の画像弊害を起こさないトナー、画像形成方法、及び、プロセスカートリッジを提供することができる。
【図面の簡単な説明】
【図１】本発明に係る電子写真画像形成装置の一実施形態を示す概略構成図である。
【図２】本発明に係るプロセスカートリッジの一実施形態における縦断面を示す縦断面図である。
【図３】本発明に従ったトナー量検知装置における第１及び第２電極の配置及び凹部を示す図である。
【図４】トナーが消費されていく時のトナーの減少状態と第１及び第２電極の位置関係を示す図である。
【図５】第１及び第２電極の一実施例を示す斜視図である。
【図６】第１及び第２電極における他の実施例を示す斜視図である。
【図７】本発明に係るプロセスカートリッジの一実施例の縦断面図である。
【図８】本発明に係るプロセスカートリッジの一実施例の縦断面図である。
【図９】第１、 第２の電極及び現像ローラの電気回路の一実施例を示す図である。
【図１０】（ａ）現像部材をコンデンサとして用いない場合と、（ｂ）現像部材をコンデンサとして用いた場合とについて、トナー量と静電容量の推移をそれぞれ示した図である。
【図１１】現像ブレード近傍のみにトナーがある状態を示す説明図である。
【図１２】トナー量検知装置の他の実施例を示す要部縦断面図である。
【図１３】現像室内のトナー量検知装置が減少していくときの底面電極とトナーの状態を示す説明図である。
【図１４】図１２のトナー量検知装置におけるトナー量と静電容量との関係を示す図である。
【図１５】本発明に用いられるトナー量検出装置の一例を説明するためのトナー容器の斜視図である。
【図１６】本発明に用いられるトナー量検出装置の他の例を説明するためのトナー容器の斜視図である。
【図１７】本発明に用いられるトナー量検出装置の他の例を説明するためのトナー容器の斜視図である。
【図１８】本発明に用いられるトナー量検出装置の他の例を説明するためのトナー容器の斜視図である。
【図１９】測定電極部材及び基準電極部材の一例を示す正面図である。
【図２０】測定電極部材及び基準電極部材の他の例を示す正面図である。
【図２１】トナー容器におけるトナー収容態様の一例を示す図である。
【図２２】本発明に用いられるトナー量検知装置の他の例を説明するためのトナー容器の斜視図である。
【図２３】トナー容器におけるトナー収容態様の他の例を示す図である。
【図２４】ドット再現性の評価に用いたチェッカー模様の説明図である。
【符号の説明】
１ 光学手段
１ａ レーザーダイオード
１ｂ ポリゴンミラー
１ｃ レンズ
１ｄ 反射ミラー
２ 記録媒体
３、６３ 搬送手段
３ａ 給紙カセット
３ｂ ピックアップローラ
３ｃ、３ｄ 搬送ローラ対
３ｅ レジストローラ対
３ｆ 搬送ガイド
３ｇ、３ｈ、３ｉ、３ｍ 排出ローラ対
３ｊ 反転経路
４ 転写ローラ
５ 定着手段
５ａ ヒータ
５ｂ 定着ローラ
５ｃ 駆動ローラ
６ 排出トレイ
７、５１ 感光体ドラム（電子写真感光体）
８ 帯電ローラ（帯電手段）
９ 現像手段
９Ａ 現像室
９ａ 現像ローラ
９ｂ トナー送り部材
９ｃ 固定磁石
９ｄ 現像ブレード
９ｅ トナー撹拌部材
９ｈ 電極棒
１０ クリーニング手段
１０ａ クリーニングブレード
１０ｂ 廃トナー溜め
１１ 枠体
１１Ａ トナー容器（トナー収納部）
１２ 現像枠体
１３ クリーニング枠体
２０Ａ 測定電極部材（第一静電容量発生部）
２０Ｂ 基準電極部材（第二静電容量発生部）
２１ 仕切壁
２２ 基板
２３、２４ 電極
２３ａ〜２３ｆ、２４ａ〜２４ｆ 電極部分
２３ｇ、２４ｇ 連結電極部分
８０ 凹部
８１ 第１電極
８２ 第２電極
８４ 経路電極
Ａ レーザービームプリンタ
Ｂ プロセスカートリッジ
Ｇ 間隔[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner for developing an electrostatic latent image formed by a method such as an electrophotographic method, an electrostatic recording method, a magnetic recording method, or a toner jet method, an image forming method, and a process cartridge.
[0002]
[Prior art]
The electrophotographic image forming apparatus employs a process cartridge system in which the electrophotographic photosensitive member and the process means acting on the photosensitive member are integrated into a cartridge, and the cartridge can be attached to and detached from the main body of the electrophotographic image forming apparatus. . According to this process cartridge system, for example, maintenance of the apparatus such as toner replenishment can be performed by the user himself / herself without depending on the service person, so that the convenience can be particularly improved. Because of these advantages, the process cartridge system is widely used in electrophotographic image forming apparatuses.
[0003]
In such a cartridge-type electrophotographic image forming apparatus, as described above, the user can replace the cartridge himself. Therefore, when the remaining amount of toner in the developing device is detected and the amount of toner decreases, There is a means for displaying and warning the user, and there is a device that prompts the user to replace the cartridge before the image density is lowered.
[0004]
Various methods have been proposed for the life detection of such a cartridge, and a method for integrating and storing the amount of use of the cartridge using a nonvolatile storage means such as an EEPROM has been proposed. For example, in Japanese Patent Application Laid-Open No. 61-185761, when a photosensitive drum in a process cartridge is exposed by a laser beam or a light emitting diode, information corresponding to the remaining amount of toner is added and stored by adding and storing exposure time information. An electrophotographic image forming apparatus having such means is described.
[0005]
In addition, since there are many opportunities for cartridges to be attached / detached / replaced to / from the apparatus main body, there is also a proposal to increase the detection accuracy when a plurality of cartridges are used for one apparatus main body by incorporating storage means. Has been made. For example, in Japanese Patent Application Laid-Open No. 63-212956, a memory is provided in the cartridge, and the apparatus body has a cartridge based on the means for reading and writing the memory, the content read from the memory, and the electrophotographic operation. There has been proposed an electrophotographic image forming apparatus that calculates information related to the lifetime of the image and writes the information in a memory.
[0006]
As another method for detecting the consumption of toner, a method for directly detecting the remaining amount of toner in the cartridge has been proposed. For example, in Japanese Patent Application Laid-Open No. 62-62352, a detection antenna is arranged in the vicinity of a developing sleeve that is a toner carrier, and when an AC voltage is applied to the developing sleeve, a current induced in the antenna is measured. It describes a method for detecting the remaining amount of toner using the fact that it changes according to the amount of toner between the sleeve and the antenna.
[0007]
Japanese Patent Laid-Open No. 5-100571 discloses a toner detection electrode member in which two parallel electrodes arranged on the same surface in parallel with a predetermined interval are combined in an uneven shape instead of two electrode rods. And a toner detection device in which the toner detection member is installed on the lower surface of the toner container. This apparatus detects a remaining amount of toner by detecting a change in electrostatic capacitance between parallel electrodes installed in a planar state.
[0008]
However, any of the above toner detection devices can only detect the presence or absence of toner in the toner container, that is, can detect that there is little toner immediately before the toner in the toner container is used up. It was not possible to detect whether the toner remained.
[0009]
On the other hand, if the toner amount in the toner container can be detected sequentially, the user can know the toner usage state in the toner container, and a new process cartridge can be prepared in accordance with the replacement time. Is convenient for users.
[0010]
Examples of such a sequential remaining amount detection system include, for example, Japanese Patent Laid-Open Nos. 2000-147891, 2000-206774, 2000-250380, 2001-27841, and 2001-27842. Although these systems are described in Japanese Laid-open Patent Publications, etc., errors still occur in some systems, and there is still room for examination of remaining amount detection with high accuracy.
[0011]
[Problems to be solved by the invention]
An object of the present invention is to accurately detect the amount of toner remaining in the developing device and the process cartridge, and to notify the user of the remaining amount of toner and the remaining number of printable sheets sequentially, which is extremely useful for the user. To provide a toner, an image forming method, and a process cartridge that can be applied to an image forming apparatus having a quantity detecting means.
[0012]
An object of the present invention is to provide a toner, an image forming method, and a process cartridge that can provide good developability and durability even in a high-speed development system.
[0013]
An object of the present invention is to provide a toner, an image forming method, and a process cartridge which can obtain good developability and durability even in a low temperature and low humidity and high temperature and high humidity environment.
[0014]
An object of the present invention is to provide a toner, an image forming method, and a process cartridge capable of obtaining good developability even after being left for a long time.
[0015]
[Means for Solving the Problems]
  The present invention is a toner used in an image forming method using a process cartridge that is detachable from the main body of the image forming apparatus and includes a toner remaining amount detecting unit that can sequentially detect the remaining amount of toner according to a change in capacitance. And
  The toner contains at least a binder resin and a wax component, and has a molecular weight of 3 × 10 in a molecular weight distribution measured by gel permeation chromatograph (GPC) soluble in tetrahydrofuran (THF) of the toner.^ThreeTo 3 × 10^FourWith a main peak and a molecular weight of 5 × 10^FourTo 3 × 10⁶In the DSC curve at the time of temperature rise measured by a differential scanning calorimeter (DSC) of the toner, at least one endothermic peak is present in the temperature range of 120 to 160 ° C.And
  The toner binder resin has a molecular weight of 3 × 10 measured by GPC at least in THF-soluble matter. ^Three To 3 × 10 ^Four Low molecular side component (L component) having a maximum value in the region, and molecular weight 5 × 10 ^Four To 3 × 10 ⁶ The ratio of styrene in the constituent monomer of the L component is 90 to 100% by mass.It is related with the toner characterized by being.
[0016]
  The present invention is also an image forming method using a process cartridge that is detachable from the main body of the image forming apparatus and includes a toner remaining amount detecting unit that can sequentially detect the remaining amount of toner according to a change in capacitance.
  The toner contains at least a binder resin and a wax component, and has a molecular weight of 3 × 10 in the molecular weight distribution measured by GPC of the THF soluble content of the toner.^ThreeTo 3 × 10^FourWith a main peak and a molecular weight of 5 × 10^FourTo 3 × 10⁶In the DSC curve at the time of temperature rise measured by DSC of the toner, it has at least one endothermic peak in the temperature range of 120 to 160 ° C.And
  The toner binder resin has a molecular weight of 3 × 10 measured by GPC at least in THF-soluble matter. ^Three To 3 × 10 ^Four Low molecular side component (L component) having a maximum value in the region, and molecular weight 5 × 10 ^Four To 3 × 10 ⁶ The ratio of styrene in the constituent monomer of the L component is 90 to 100% by mass.The present invention relates to an image forming method.
[0017]
  Furthermore, the present invention provides a process cartridge including a toner remaining amount sequential detection unit that is detachable from the image forming apparatus main body and that can sequentially detect the remaining amount of toner according to a change in capacitance.
  The toner used contains at least a binder resin and a wax component, and has a molecular weight of 3 × 10 in the molecular weight distribution measured by GPC of the THF soluble part of the toner.^ThreeTo 3 × 10^FourWith a main peak and a molecular weight of 5 × 10^FourTo 3 × 10⁶In the DSC curve at the time of temperature rise measured by DSC of the toner, it has at least one endothermic peak in the temperature range of 120 to 160 ° C.And
  The toner binder resin has a molecular weight of 3 × 10 measured by GPC at least in THF-soluble matter. ^Three To 3 × 10 ^Four Low molecular side component (L component) having a maximum value in the region, and molecular weight 5 × 10 ^Four To 3 × 10 ⁶ The ratio of styrene in the constituent monomer of the L component is 90 to 100% by mass.The present invention relates to a process cartridge.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Conventionally, the sequential remaining amount detecting means has been improved from only the developing device, but there are cases where the remaining amount of toner varies. In particular, in the method of detecting the remaining amount of toner by installing an electrode in the toner container, the toner movement is delayed due to the movement of the toner around the electrode, and the developability and the image are whitened (hereinafter referred to as fade). (Referred to as a “bending phenomenon”), or toner adhesion to the electrode portion is caused to deteriorate the accuracy of remaining toner detection.
[0019]
As a result of intensive studies, the inventors have discovered that by selecting a combination of specific toner characteristics and specific remaining amount detection means, the accuracy of sequential detection of the remaining amount of toner can be improved more than ever. Invented.
[0020]
That is, the toner contains at least a binder resin and a wax component, and in the molecular weight distribution measured by GPC of the THF soluble content of the toner, the molecular weight is 3 × 10.^ThreeTo 3 × 10^FourWith a main peak and a molecular weight of 5 × 10^FourTo 3 × 10⁶In the DSC curve at the time of temperature rise measured by a differential scanning calorimeter (DSC) of the toner, it has at least one endothermic peak in the temperature range of 120 to 160 ° C. In some cases, it has been found that the accuracy of detecting the remaining amount of toner is higher than ever.
[0021]
When the molecular weight distribution is in the above range, it is possible to balance the fixing property and the anti-offset property, thereby suppressing the aggregation of the toner particles and the adhesion to the toner container and the toner remaining amount detecting means, and the toner remaining amount. This makes it possible to improve the accuracy of detecting the amount, achieve a highly accurate sequential remaining amount detection system, and maintain the high fluidity of the toner. The movement of the film is not suppressed, and the developability is not deteriorated.
[0022]
Further, when the endothermic peak of the toner is within the above range, the toner releasability is improved and the adhesion is suppressed, so that the remaining amount detection accuracy can be improved.
[0023]
The toner of the present invention has a molecular weight of 3 × 10 in the molecular weight distribution measured by GPC of the THF soluble component.^ThreeTo 3 × 10^Four, Preferably 5 × 10^ThreeTo 2 × 10^FourWith a main peak and a molecular weight of 5 × 10^FourTo 3 × 10⁶, Preferably 1 × 10^FiveTo 2 × 10⁶More preferably 3 × 10^FiveTo 2 × 10⁶The region has a sub-peak or shoulder in the region.
[0024]
In the molecular weight distribution, the toner has such a molecular weight distribution, so that a good balance between fixing and offset resistance is maintained, as well as suppressing toner cohesion, and toner container and toner remaining amount detecting means. Adhesion to can be suppressed. That is, the molecular weight on the low molecular side is 3 × 10^ThreeIf it is less than 1, offset resistance is impaired, toners tend to aggregate together, and preferable charging cannot be obtained, causing problems such as thin image density and fogging. In addition, since it tends to adhere to the toner container and the toner remaining amount detecting means, the movement of the toner is delayed, the developability such as the image density and the fog is deteriorated, and the fading phenomenon due to the insufficient toner conveyance amount occurs. End up. Further, since the toner tends to adhere to the toner remaining amount detecting means, the accuracy of the remaining amount detection becomes inferior, and the accurate toner remaining amount cannot be detected.
[0025]
The molecular weight on the low molecular side is 3 × 10^FourIf it is larger, the fixability will be adversely affected, and the viscosity of the resin component will increase, making it difficult to disperse the raw materials in the toner, making it easier to cause a decrease in density, fogging, etc. As a result, the free raw material component easily adheres to the toner remaining amount detecting means, and detection with high accuracy cannot be performed.
[0026]
Furthermore, the molecular weight on the polymer side is 5 × 10^FourIf it is smaller, offset resistance is adversely affected, and the toner tends to adhere to the toner container and the toner remaining amount detecting means, causing a fading phenomenon and a decrease in remaining amount detection accuracy. The molecular weight on the high molecular weight side is 3 × 10⁶If it is larger, the fixing property will be adversely affected, and the low molecular weight component in the resin will be separated from the molecular weight, increasing the non-uniformity of the resin and increasing the amount of raw material components that are freed during pulverization. It adheres and the remaining amount detection accuracy is lowered, and the chargeability and the like are adversely affected to cause density reduction and fogging.
[0027]
Here, the molecular weight distribution by GPC using THF (tetrahydrofuran) of the toner or binder resin of the present invention as a solvent can be measured, for example, under the following conditions.
[0028]
First, the column is stabilized in a heat chamber at 40 ° C., and tetrahydrofuran (THF) is allowed to flow through the column at this temperature as a solvent at a flow rate of 1 ml / min, and about 100 μl of a sample THF solution is injected for measurement. . In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the number of counts.
[0029]
As a standard polystyrene sample for preparing a calibration curve, for example, a molecular weight of 10 manufactured by Tosoh Corporation or Showa Denko KK is 10²-10⁷It is appropriate to use a standard polystyrene sample of about 10 points. An RI (refractive index) detector is used as the detector. As the column, it is preferable to combine a plurality of commercially available polystyrene gel columns. For example, a combination of shodex GPC KF-801, 802, 803, 804, 805, 806, 807, and 800P manufactured by Showa Denko KK or TSKgel G1000H (H_XL), G2000H (H_XL), G3000H (H_XL), G4000H (H_XL), G5000H (H_XL), G6000H (H_XL), G7000H (H_XL), A combination of TSK guard column.
[0030]
A sample for molecular weight distribution measurement is prepared as follows. Put the toner sample in THF and let it stand for several hours, then shake well and mix well with THF (until the sample is no longer united), and let stand for more than 12 hours. At this time, the sample is left in THF for 24 hours or longer. Thereafter, a sample processing filter (pore size 0.45 to 0.5 μm, for example, Mysori Disc H-25-5 manufactured by Tosoh Corporation, Excro Disc 25CR manufactured by Gelman Science Japan Co., Ltd., etc.) can be used. A measurement sample for GPC is used. The sample concentration is adjusted so that the resin component is 0.5 to 5 mg / ml.
[0031]
The types of binder resins used in the toner of the present invention include styrene resins, styrene copolymer resins, polyester resins, polyol resins, polyvinyl chloride resins, phenol resins, natural modified phenol resins, natural resin modified maleic acids. Examples include resins, acrylic resins, methacrylic resins, polyvinyl acetate, silicone resins, polyurethane resins, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resins, coumarone indene resins, and petroleum resins.
[0032]
The binder resin of the toner of the present invention is preferably a styrene resin, and the proportion of styrene in the constituent monomer of the binder resin is 80 to 99% by mass, preferably 85 to 99% by mass, and more preferably. 90 to 99% by mass is preferable for controlling the degree of aggregation and adhesion of the toner.
[0033]
When the styrene component is less than 80% by mass, the toner becomes fragile against impact and wear, and in a state where the toner is constantly stirred for a long period of time, for example, the toner collapses during use, and ultrafine powder is generated. As a result, the ultra fine powder tends to adhere to the toner remaining amount detecting means, which may affect the accuracy of toner remaining amount detection, which is not preferable. On the other hand, if it exceeds 99% by mass, it becomes difficult to obtain a preferable one due to the relationship between the glass transition temperature and the molecular weight of the resin, and it tends to be excessively charged in an environment such as low temperature and low humidity, which adversely affects fog and the like. In addition, electrostatic aggregation tends to occur, which is not preferable.
[0034]
As a comonomer for the styrene monomer of the styrene copolymer, styrene derivatives such as vinyltoluene; acrylic acid; methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, acrylic Acrylic esters such as phenyl acid; methacrylic acid; methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate; maleic acid; double such as butyl maleate, methyl maleate, dimethyl maleate Dicarboxylic acid ester having a bond; acrylamide, acrylonitrile, methacrylonitrile, butadiene; vinyl chloride; vinyl ester such as vinyl acetate and vinyl benzoate; ethylene, propylene, butylene Such ethylenic olefins, vinyl methyl ketone, such as vinyl vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether, vinyl propionate ether. These vinyl monomers are used alone or in combination.
[0035]
The binder resin of the toner has a glass transition temperature (Tg) of 45 to 80 ° C., preferably 50 to 70 ° C., from the viewpoint of storage stability of the toner. If Tg is too lower than the above range, the toner is likely to be deteriorated in a high temperature atmosphere, and offset is liable to occur during fixing. On the other hand, if Tg is too higher than the above range, the fixability tends to decrease.
[0036]
Examples of the polymerization method that can be used as the synthesis method of the binder resin of the present invention include a solution polymerization method, an emulsion polymerization method, and a suspension polymerization method.
[0037]
Among them, the emulsion polymerization method is a method in which a monomer (monomer) almost insoluble in water is dispersed as small particles in an aqueous phase with an emulsifier, and polymerization is performed using a water-soluble polymerization initiator. In this method, the heat of reaction can be easily adjusted, and the termination reaction rate is low because the phase in which the polymerization is carried out (the oil phase consisting of the polymer and the monomer) and the aqueous phase are separate. As a result, the polymerization rate can be increased and a high polymerization degree can be obtained. Furthermore, the reason is that the polymerization process is relatively simple, and that the polymerization product is fine particles, so that it can be easily mixed with colorants, charge control agents and other additives in the production of toner. Therefore, there is an advantage as a method for producing a binder resin for toner.
[0038]
However, in the emulsion polymerization method, the resulting polymer tends to be impure due to the added emulsifier, and operations such as salting out are necessary to take out the polymer. Suspension polymerization is convenient to avoid this inconvenience.
[0039]
In suspension polymerization, it is good to carry out by 100 mass parts or less (preferably 10-90 mass parts) of monomers with respect to 100 mass parts of aqueous solvents. Examples of the dispersant that can be used include polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, and the like, and 0.05 to 1 part by mass is generally used with respect to 100 parts by mass of the aqueous solvent. The polymerization temperature is suitably 50 to 95 ° C., but is appropriately selected depending on the polymerization initiator used and the polymer to be produced.
[0040]
The binder resin used in the present invention is preferably produced using a polyfunctional polymerization initiator alone or a monofunctional polymerization initiator as exemplified below.
[0041]
Specific examples of the polyfunctional polymerization initiator having a polyfunctional structure include 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,3-bis- (t-butylperoxy Isopropyl) benzene, 2,5-dimethyl-2,5-di- (t-butylperoxy) hexane, tris- (t-butylperoxy) triazine, 1,1-di-t-butylperoxycyclohexane, 2 , 2-di-t-butylperoxybutane, 4,4-di-t-butylperoxyvaleric acid-n-butyl ester, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxy Azelate, di-t-butylperoxytrimethyladipate, 2,2-bis- (4,4-di-t-butylperoxycyclohexyl) propane, 2 A polyfunctional polymerization initiator having a functional group having a polymerization initiating function such as two or more peroxide groups in one molecule such as 2-t-butylperoxyoctane and various polymer oxides; and diallyl peroxydicarbonate, Both a functional group having a polymerization initiating function such as a peroxide group and a polymerizable unsaturated group in one molecule such as t-butylperoxymaleic acid, t-butylperoxyallyl carbonate, and t-butylperoxyisopropyl fumarate And a polyfunctional polymerization initiator having
[0042]
Of these, more preferred are 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-di-t-butylperoxycyclohexane, di-t-butylperoxy. Hexahydroterephthalate, di-t-butylperoxyazelate and 2,2-bis- (4,4-di-t-butylperoxycyclohexyl) propane, and t-butylperoxyallyl carbonate.
[0043]
These polyfunctional polymerization initiators are preferably used in combination with a monofunctional polymerization initiator in order to satisfy various performances required as a binder resin for the toner. In particular, it is preferable to use in combination with a polymerization initiator having a decomposition temperature for obtaining a half-life of 10 hours, which is lower than the decomposition temperature for obtaining a half-life of 10 hours of the polyfunctional polymerization initiator. Specific examples of such a monofunctional polymerization initiator include organic peroxides such as benzoyl peroxide, dicumyl peroxide, t-butyl peroxycumene, and di-t-butyl peroxide, azobisiso Examples include azo and diazo compounds such as butyronitrile and diazoaminoazobenzene.
[0044]
These monofunctional polymerization initiators may be added to the monomer at the same time as the polyfunctional polymerization initiator, but in order to keep the efficiency of the polyfunctional polymerization initiator appropriate, in the polymerization step, It is preferably added after the half-life indicated by the polyfunctional polymerization initiator has elapsed.
[0045]
These initiators are preferably used in an amount of 0.05 to 2 parts by mass with respect to 100 parts by mass of the monomer from the viewpoint of efficiency.
[0046]
The binder resin is also preferably crosslinked with a crosslinkable monomer.
[0047]
As the crosslinkable monomer, a monomer having two or more polymerizable double bonds is mainly used. Specific examples include aromatic divinyl compounds (eg, divinylbenzene, divinylnaphthalene, etc.); diacrylate compounds linked by alkyl chains (eg, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4 -Butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and acrylates of the above compounds replaced with methacrylate); alkyl chain containing an ether bond Diacrylate compounds (eg, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, Ethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and acrylates of the above compounds in place of methacrylate); diacrylate compounds linked by a chain containing an aromatic group and an ether bond (eg, polyoxyethylene) (2) -2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4-hydroxyphenyl) propane diacrylate, and methacrylates of the above compounds In addition, polyester-type diacrylate compounds (for example, trade name MANDA (Nippon Kayaku)) can be mentioned. Polyfunctional crosslinkers include pentaerythritol acrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and acrylates of the above compounds to methacrylate. Substituted ones: triallyl cyanurate and triallyl trimellitate.
[0048]
These crosslinking agents are preferably used in the range of 0.00001 to 1 part by mass, preferably 0.001 to 0.05 part by mass, with respect to 100 parts by mass of the other monomer components.
[0049]
Among these crosslinkable monomers, aromatic divinyl compounds (especially divinylbenzene), diethers linked by a chain containing an aromatic group and an ether bond are preferably used from the viewpoint of toner fixing properties and offset resistance. Examples include acrylate compounds.
[0050]
As other synthesis methods, a bulk polymerization method and a solution polymerization method can be used. In the bulk polymerization method, an arbitrary polymer can be obtained by increasing the termination reaction rate by polymerizing at a high temperature, but there is a problem that the reaction is difficult to control. In that respect, in the solution polymerization method, a low molecular weight polymer can be easily obtained under mild conditions by utilizing the difference in radical chain transfer caused by the solvent and adjusting the initiator amount and reaction temperature. It is preferable to obtain a low molecular weight body in the composition containing the binder resin used in the present invention. In particular, a solution polymerization method under a pressurized condition is also preferable in that the amount of the initiator used is minimized and the influence of the remaining initiator is minimized.
[0051]
Examples of the monomer for obtaining the binder resin of the present invention include the following. Styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethyl Styrene, pn-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene Styrene and its derivatives such as; ethylene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated polyenes such as butadiene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; Vinyl esthetics such as vinyl acetate, vinyl propionate, vinyl benzoate, etc. Methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, methacrylic acid Methacrylic acid esters such as dimethylaminoethyl and diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, acrylic acid Acrylic acid esters such as 2-ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate; vinyl methyl ether, vinyl ethyl ether, vinyl isobuty Vinyl ethers such as ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; Vinyl Naphthalenes; acrylic acid derivatives or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide. These vinyl monomers are used alone or in admixture of two or more monomers.
[0052]
Among these, a combination of monomers that becomes a styrene copolymer or a styrene acrylic copolymer is preferable.
[0053]
As a method for producing a binder resin, a high molecular weight polymer and a low molecular weight polymer are synthesized separately by a solution polymerization method, then mixed in a solution state and then desolvated, or by an extruder or the like. Dissolve in low-molecular-weight polymer obtained by melt-kneading dry blend method, solution polymerization method, etc. in monomers constituting high-molecular-weight polymer, perform suspension polymerization, wash and dry to obtain resin composition A two-stage polymerization method and the like are also included. However, the dry blend method has a problem in terms of uniform dispersion and compatibility. In addition, the two-stage polymerization method has many advantages in uniform dispersibility, but the solution blend method can increase the low molecular weight component to a higher molecular weight component, and the high molecular weight can be increased in the presence of the low molecular weight polymer component. The solution blending method is most suitable because it can synthesize a molecular weight polymer and there are few problems such as unnecessary formation of a low molecular weight polymer as a by-product. In order to impart the molecular weight distribution characteristic of the present invention to the toner, a method in which a low molecular weight component and a high molecular weight component are synthesized in separate processes and then blended in a solution is preferable.
[0054]
The binder resin of the toner of the present invention has a molecular weight of 3 × 10 measured at least by GPC of a THF soluble component.^ThreeTo 3 × 10^FourLow molecular side component (L component) having a maximum value in the region, and a molecular weight of 5 × 10^FourTo 3 × 10⁶The ratio of styrene in the constituent monomer of the L component is 90 to 100% by mass, preferably 95 to 100% by mass. .
[0055]
Since the L component controls the fixing property, the influence on the viscoelasticity of the entire toner is increased, and the influence on the adhesion and aggregation properties of the toner is also increased. From the viewpoint of controlling If the ratio of L component styrene is less than 90% by mass, the toner will be brittle with respect to impact and wear, and the toner will collapse during use over a long period of time, generating super fine powder. This is not preferable because the super fine powder tends to adhere to the toner remaining amount detecting means, which may affect the toner remaining amount detection accuracy. In particular, the cohesiveness is likely to increase under high temperature and high humidity, which is not preferable because the adhesion becomes high and the accuracy of detecting the remaining amount of toner may be further deteriorated.
[0056]
The composition of the polyester resin used as the binder resin in the present invention is as follows.
[0057]
Examples of the divalent alcohol component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1, Examples include 6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, and bisphenol represented by formula (A) and derivatives thereof.
[0058]
[Chemical 1]

(In the formula, R is an ethylene or propylene group, x and y are each an integer of 0 or more, and the average value of x + y is 0 to 10.)
[0059]
Furthermore, the diol shown by Formula (B) is mentioned as a bivalent alcohol component.
[0060]
[Chemical formula 2]

[0061]
Divalent acid components include benzene dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride, or anhydrides thereof, lower alkyl esters; alkyls such as succinic acid, adipic acid, sebacic acid, and azelaic acid. Dicarboxylic acids or anhydrides thereof or lower alkyl esters thereof; alkenyl succinic acids or alkyl succinic acids such as n-dodecenyl succinic acid, n-dodecyl succinic acid, anhydrides thereof or lower alkyl esters thereof; Examples thereof include unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, and itaconic acid, or anhydrides thereof, and dicarboxylic acids such as lower alkyl esters thereof and derivatives thereof.
[0062]
Moreover, it is preferable to use together the trihydric or more alcohol component and trivalent or more acid component which work also as a crosslinking component.
[0063]
Examples of the trihydric or higher polyhydric alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol. 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene, etc. Can be mentioned.
[0064]
Examples of the trivalent or higher polyvalent carboxylic acid component include trimellitic acid, pyromellitic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, and 2,5,7-naphthalene. Tricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, Tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, empole trimer acid, and their anhydrides, lower alkyl esters;
[0065]
[Chemical Formula 3]

(In the formula, X is an alkylene group having 1 or more carbon side chains of 1 or more carbon atoms or an alkenylene group)
And polycarboxylic acids such as tetracarboxylic acids and their anhydrides and lower alkyl esters thereof and derivatives thereof.
[0066]
The alcohol component is 40 to 60 mol%, preferably 45 to 55 mol%, and the acid component is 60 to 40 mol%, preferably 55 to 45 mol%. Moreover, it is preferable that the component of the polyhydric alcohol more than trivalence is 1-60 mol% in all the components. The polyester resin is also obtained by a generally known condensation polymerization.
[0067]
The toner of the present invention is preferably used as a magnetic toner containing a magnetic material. Examples of magnetic materials that can be used include metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum, and silicon. These magnetic particles preferably have a BET specific surface area of 1 to 20 m by a nitrogen adsorption method.²/ G, especially 2.5-12m²/ G, and magnetic powder having a Mohs hardness of 5 to 7 is preferred. Examples of the shape of the magnetic body include octahedron, hexahedron, spherical shape, needle shape, and scale shape, but those having less anisotropy such as octahedron, hexahedron, and spherical shape are preferable. This is because those having an isotropic shape can achieve good dispersion in the toner. The average particle size of the magnetic material is preferably 0.05 to 1.0 μm, more preferably 0.1 to 0.6 μm, and further preferably 0.1 to 0.4 μm.
[0068]
The magnetic material is preferably added in an amount of 40 to 200 parts by weight, particularly preferably 50 to 150 parts by weight, based on 100 parts by weight of the toner binder resin. If the amount is less than 40 parts by mass, the toner transportability is insufficient, and it tends to cause adhesion / remaining on the toner container or the like, or the toner layer on the developer carrying member tends to be uneven, resulting in image unevenness. Furthermore, the image density tends to decrease due to an excessive increase in charge of the toner. On the other hand, when the amount exceeds 200 parts by mass, the toner cannot be sufficiently charged, and the image density is likely to be lowered.
[0069]
In the present invention, each physical property of magnetic iron oxide is measured by the following method.
[0070]
(1) Particle size and shape of magnetic iron oxide: Transmission electron microscope (TEM) H-700H, H-800, H-7500 (all manufactured by Hitachi, Ltd.) or scanning electron microscope (SEM) S-800 , S-4700 (all manufactured by Hitachi, Ltd.) can be used to photograph magnetic iron oxide at 20,000 to 200,000 times, and the sample can be observed at an arbitrary magnification as a baking magnification of 1 to 10 times. . For the particle size, 100 particles of 0.03 μm or more are selected at random, the maximum length (μm) of each particle is measured, and the average is taken as the number average particle size.
[0071]
(2) BET specific surface area: The BET specific surface area is determined by the BET multipoint method using a fully automatic gas adsorption amount measuring device: Autosorb 1 manufactured by Yuasa Ionics Co., Ltd., using nitrogen as the adsorption gas. In addition, as pre-processing of a sample, deaeration for 1 hour is performed at 50 degreeC.
[0072]
The toner of the present invention has at least one endothermic peak in the DSC curve at the time of temperature rise measured by a differential scanning calorimeter (DSC), and the endothermic peak is 120 to 160 ° C, preferably 120 to 150 ° C. Preferably it exists in 125-145 degreeC. Two or more endothermic peaks may exist, and in that case, it is preferable to have at least one endothermic peak at 120 to 160 ° C. From the DSC curve at the time of temperature rise, the melting behavior accompanying the endothermic toner can be seen. When the endothermic peak is present at 120 to 160 ° C., the toner becomes strong against frictional heat, and the slipperiness of the toner can be ensured even when used for a long time, and appropriate adhesion resistance and fluidity can be ensured.
[0073]
If the endothermic peak is present only at a temperature of less than 120 ° C., the toner tends to adhere to the toner remaining amount detecting means because the toner is likely to be thermally softened, and to the toner remaining amount detecting means. The toner remains when the image quality is slow, developability such as image density / fogging deteriorates, toner transportability deteriorates, fading occurs, the temperature rises at high temperatures or during high durability. Quantity detection accuracy will be inferior. Further, if the endothermic peak exists only at a temperature exceeding 160 ° C., dispersion of each material in the toner is deteriorated, and fog may be deteriorated. The endothermic peak of the toner of the present invention is caused by the wax contained in the toner, and a desired endothermic peak can be obtained by selecting an appropriate wax and incorporating it in the toner. The wax capable of imparting such an endothermic peak to the toner has a great influence on the adhesion of the toner due to its releasability, and can effectively impart good flow characteristics to the toner.
[0074]
In the present invention, the DSC curve of the toner uses a differential scanning calorimeter (DSC measuring device) such as DSC-7 (manufactured by PerkinElmer) or DSC2920 (manufactured by TA Instruments Japan) according to ASTM D3418-82. Measure. The DSC curve is a DSC curve that is measured when the temperature is raised at a rate of 10 ° C./min after the temperature is raised and lowered once and the previous history is taken.
[0075]
In the toner of the present invention, it is preferable to use an organometallic compound as a charge control agent, and in particular, a toner containing an organic compound as a ligand or counter ion is useful. As such a metal complex, a metal complex type monoazo compound is preferably used from the viewpoint of chargeability. Examples of the metal complex type monoazo compound include metal complexes of monoazo dyes described in JP-B Nos. 41-20153, 42-27596, 44-6397, and 45-26478. In particular, from the viewpoint of dispersibility and chargeability, a metal complex type monoazo compound represented by the following general formula (I) is preferable, and among them, a metal complex type monoazo iron complex whose central metal is iron is preferably used. . More preferably, a monoazo iron complex represented by the following general formula (II) is used.
[0076]
[Formula 4]

[0077]
[Chemical formula 5]

[Where X₁, X₂Hydrogen atom, lower alkyl group, lower alkoxy group, nitro group, halogen atom
m, m ′; an integer of 1 to 3
Y₁, Y_ThreeHydrogen atom, C₁~ C₁₈Alkyl, alkenyl, sulfonamide, mesyl, sulfonic acid, carboxy ester, hydroxy, C₁~ C₁₈Alkoxy, acetylamino, benzoyl, amino group, halogen atom
n, n '; an integer of 1 to 3
Y₂, Y_Four; Hydrogen atom, nitro group
(X above₁And X₂, M and m ', Y₁And Y_Three, N and n ', Y₂And Y_FourMay be the same or different. )
A⁺A mixture of ammonium ion, alkali metal ion and hydrogen ion. ]
[0078]
The content of the metal complex type monoazo compound is preferably 0.05 to 5 parts by mass, particularly preferably 0.2 to 3 parts by mass with respect to 100 parts by mass of the toner binder resin. If the content of the metal complex type monoazo compound is too large, the fluidity of the toner is deteriorated and fog is likely to occur. On the other hand, if the content is too small, it is difficult to obtain a sufficient charge amount.
[0079]
In the present invention, any appropriate pigment or dye is used as the colorant. Toner colorants are well known, and examples of the pigment include carbon black, aniline black, acetylene black, naphthol yellow, Hansa yellow, rhodamine lake, alizarin lake, Bengala, phthalocyanine blue, and indanthrene blue. These are used in an amount necessary and sufficient to maintain the optical density of the fixed image, and an addition amount of 0.1 to 20 parts by mass, preferably 0.2 to 10 parts by mass is preferable with respect to 100 parts by mass of the resin. For the same purpose, a dye is further used. For example, there are azo dyes, anthraquinone dyes, xanthene dyes, methine dyes, and the like, and an addition amount of 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight, is good with respect to 100 parts by weight of the resin.
[0080]
The wax contained in the toner of the present invention has at least one endothermic peak in the DSC curve at the time of temperature rise measured by a differential scanning calorimeter (DSC), and the endothermic peak is 120 to 160 ° C., preferably 120 ° C. It is preferable that it exists in -150 degreeC, More preferably, it exists in 125-145 degreeC. Two or more endothermic peaks may exist, and in that case, it is preferable to have at least one endothermic peak at 120 to 160 ° C. When the wax has an endothermic peak in the above temperature range, a preferable endothermic property can be imparted to the toner.
[0081]
The wax contained in the toner of the present invention includes aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, olefin copolymers, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; fats such as oxidized polyethylene wax. Oxides of aromatic hydrocarbon waxes or block copolymers thereof; waxes based on fatty acid esters such as carnauba wax and montanate wax; part or all of fatty acid esters such as deoxidized carnauba wax And the like which are deoxidized. Further, saturated straight chain fatty acids such as palmitic acid, stearic acid, montanic acid, or long-chain alkyl carboxylic acids having a long-chain alkyl group; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinal acid; Saturated alcohols such as stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, seryl alcohol, melyl alcohol, or long-chain alkyl alcohols having a long-chain alkyl group; polyhydric alcohols such as sorbitol; linoleic acid Fatty acid amides such as amides, oleic acid amides, lauric acid amides; saturated fatty acid vinyls such as methylene bisstearic acid amides, ethylene biscapric acid amides, ethylene bislauric acid amides, hexamethylene bisstearic acid amides. Amides, unsaturated fatty acid amides such as ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide; Aromatic bisamides such as acid amides and N, N'-distearylisophthalamide; waxes grafted to aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid; behenic acid monoglycerides Examples include partially esterified products of fatty acids and polyhydric alcohols such as: methyl ester compounds having a hydroxy group obtained by hydrogenating vegetable oils and the like.
[0082]
The wax preferably used is a low molecular weight alkylene polymer obtained by polymerizing alkylene with radical polymerization under high pressure or Ziegler catalyst, metallocene catalyst or other catalyst under low pressure; obtained by thermally decomposing high molecular weight alkylene polymer. A low molecular weight alkylene polymer produced as a by-product in the polymerization of the alkylene polymer; and a hydrocarbon distillation residue obtained by the age method from a synthesis gas composed of carbon monoxide and hydrogen, or these Examples thereof include wax obtained by extracting and fractionating specific components from a synthetic hydrocarbon obtained by hydrogenation. These waxes may contain an antioxidant. Furthermore, a wax formed from a linear alcohol, a fatty acid, an acid amide, an ester, or a montan derivative may be mentioned. Further, those from which impurities such as fatty acids have been removed in advance are also preferred.
[0083]
Particularly preferred waxes are polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-α olefin copolymer, and propylene-α olefin copolymer polymerized with a metallocene catalyst. These are preferable because the toner is imparted with adhesion resistance and fluidity.
[0084]
It is effective that the wax used in the present invention is added in an amount of 0.1 to 15 parts by mass, preferably 0.5 to 12 parts by mass with respect to 100 parts by mass of the binder resin. It is also preferable to use together.
[0085]
The toner of the present invention is preferably mixed with an inorganic fine powder in order to improve environmental stability, charging stability, developability, fluidity, and storage stability. The inorganic fine powder is preferably externally added to the toner. The inorganic fine powder is preferably a hydrophobic inorganic fine powder. Examples of the inorganic fine powder include silica fine powder, titanium oxide fine powder, and hydrophobized products thereof. They are preferably used alone or in combination.
[0086]
Examples of the silica fine powder include both a dry process produced by vapor phase oxidation of a silicon halide compound or a dry silica called fumed silica and a wet silica produced from water glass, etc. Dry silica with few silanol groups and no production residue is preferred.
[0087]
Further, the silica fine powder is preferably hydrophobized. The hydrophobizing treatment is applied by chemically treating with an organosilicon compound that reacts or physically adsorbs with silica fine powder. Preferable methods include a method in which a dry silica fine powder produced by vapor phase oxidation of a silicon halogen compound is treated with a silane compound or treated with a silane compound and simultaneously with an organosilicon compound such as silicone oil.
[0088]
The silane compounds used for the hydrophobization treatment include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethyl. Chlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilane mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane , Dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldi Examples thereof include siloxane and 1,3-diphenyltetramethyldisiloxane.
[0089]
Examples of the organosilicon compound include silicone oil. As a preferable silicone oil, the viscosity at 25 ° C. is about 30 to 1,000 mm.²/ S is used. For example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, and fluorine modified silicone oil are preferred.
[0090]
A particularly preferable method is a method of treating with dimethyl silicone oil. Silica fine powder hydrophobized with dimethylsilicone oil has moderate hydrophobicity and excellent slipperiness, so that it adheres to the toner container and the toner remaining amount detecting means in long-term use. It is possible to effectively prevent the image density from being lowered by fusing to the developing sleeve.
[0091]
The silicone oil treatment method may be performed by directly mixing silica fine powder treated with a silane compound and silicone oil using a mixer such as a Henschel mixer, or by jetting a silica silicate silicone oil as a base. Also good. Alternatively, the silicone oil may be dissolved or dispersed in an appropriate solvent, and then mixed with the base silica fine powder to remove the solvent.
[0092]
As a preferable hydrophobizing treatment of the silica fine powder, there is a method of preparing by treating with dimethyldichlorosilane, then treating with hexamethyldisilazane, and then treating with silicone oil.
[0093]
As described above, it is preferable to treat the silica fine powder with two or more silane compounds, and then to treat with oil later, since the hydrophobicity can be effectively increased.
[0094]
The silica fine powder is preferably subjected to a hydrophobization treatment, and further, an oil treatment applied to the titanium oxide fine powder, similarly to the silica-based one.
[0095]
If necessary, additives other than silica fine powder or titanium oxide fine powder may be externally added to the toner of the present invention. Examples thereof include resin fine particles and inorganic fine particles that function as a charge auxiliary agent, a conductivity imparting agent, a fluidity imparting agent, an anti-caking agent, a release agent at the time of heat roll fixing, a lubricant, and an abrasive.
[0096]
The fine resin particles preferably have an average particle size of 0.03 to 1.0 μm. As the polymerizable monomer constituting the resin, styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene derivatives; acrylic acid; methacrylic acid; methyl acrylate , Ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate Acrylic acid esters such as: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, Lil, phenyl methacrylate, dimethylaminoethyl methacrylate, such as methacrylic acid esters of diethylaminoethyl methacrylate; acrylonitrile, methacrylonitrile, and the like monomers acrylamide.
[0097]
Examples of the polymerization method include suspension polymerization, emulsion polymerization, and soap-free polymerization. More preferably, particles obtained by soap-free polymerization are good.
[0098]
Other fine particles include a lubricant such as fluorine resin, zinc stearate and polyvinylidene fluoride (especially preferred is polyvinylidene fluoride); an abrasive such as cerium oxide, silicon carbide and strontium titanate (especially strontium titanate is preferred). ); Fluidity-imparting agents such as titanium oxide and aluminum oxide (in particular, hydrophobic agents are preferred); anti-caking agents; and conductivity-imparting agents such as carbon black, zinc oxide, antimony oxide and tin oxide. Further, a small amount of white fine particles and black fine particles having a polarity opposite to that of the toner may be used as a developability improver.
[0099]
The resin fine particles, the inorganic fine powder, or the hydrophobic inorganic fine powder mixed with the toner may be used in an amount of 0.1 to 5 parts by mass (preferably 0.1 to 3 parts by mass) with respect to 100 parts by mass of the toner. .
[0100]
The weight average particle diameter and particle size distribution of the toner are determined using a Coulter counter method. For example, a Coulter Multisizer (manufactured by Coulter Inc.) can be used. As the electrolytic solution, a 1% NaCl aqueous solution is prepared using primary sodium chloride. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 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, and the volume and number of toner particles of 2.00 μm or more are measured using the 100 μm aperture as the aperture by the measuring device. Volume distribution and number distribution are calculated. Then, the weight average particle diameter (D) determined from the volume distribution according to the present invention._Four) Is calculated.
[0101]
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 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Use 13 channels less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm.
[0102]
As a method for producing the toner of the present invention, the above-described toner constituent materials are sufficiently mixed by a ball mill or other mixer, and then kneaded well using a heat kneader such as a hot roll kneader or an extruder, and then solidified by cooling. Thereafter, a method of obtaining toner by mechanically pulverizing and classifying the pulverized powder is preferable. In addition, a polymerized toner manufacturing method in which a predetermined material is mixed with a monomer to constitute a binder resin to form an emulsion suspension, and then polymerized to obtain a toner; a so-called core material and shell material are used. Examples of the microcapsule toner include a method in which a predetermined material is contained in the core material, the shell material, or both; and a method in which the constituent material is dispersed in the binder resin solution and then spray dried to obtain the toner. Furthermore, if necessary, desired additives and toner particles can be sufficiently mixed by a mixer such as a Henschel mixer to produce the toner of the present invention.
[0103]
For example, as a mixer, Henschel mixer (Mitsui Mining Co., Ltd.); Super mixer (Kawata Co., Ltd.); Ribocorn (Okawara Seisakusho Co., Ltd.); (Pacific Kiko Co., Ltd.); Ladige mixer (Matsubo Co., Ltd.), and KRC kneader (Kurimoto Iron Works Co.); Bus Co Kneader (Buss Co.); TEM type extruder (Manufactured by Toshiba Machine Co., Ltd.); TEX twin-screw kneader (manufactured by Nippon Steel Works); PCM kneader (manufactured by Ikekai Iron Works); three roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho); Mining company); MS pressure kneader, Nider Ruder (Moriyama Seisakusho); Banbury mixer (Kobe Steel) As a pulverizer, a counter jet mill, a micron jet, an inomizer (manufactured by Hosokawa Micron Co.); an IDS type mill, a PJM jet pulverizer (manufactured by Nippon Pneumatic Industry Co., Ltd.); a cross jet mill (manufactured by Kurimoto Iron Works Co., Ltd.); ULMAX (manufactured by Nisso Engineering Co., Ltd.); SK Jet O Mill (manufactured by Seishin Enterprise Co., Ltd.); Kryptron (manufactured by Kawasaki Heavy Industries Co., Ltd.); turbo mill (manufactured by Turbo Kogyo Co., Ltd.). , Micron Classifier, Spedic Classifier (manufactured by Seishin Enterprise Co., Ltd.); Turbo Classifier (Nisshin Engineering Co., Ltd.); Micron Separator, Turboplex (ATP), TSP Separator (manufactured by Hosokawa Micron Corporation); Elbow Jet (Nittetsu Mining) ), Dispa John separator (manufactured by Nippon Pneumatic Kogyo Co., Ltd.); YM micro cut (manufactured by Yaskawa Shoji Co., Ltd.) can be cited as a granulator. As the sieving device used, Ultrasonic (manufactured by Sakae Sangyo Co., Ltd.); Resonator Sheave, Gyroshifter (manufactured by Tokuju Kogakusho Co., Ltd.); Vibrasonic System (manufactured by Dalton Co., Ltd.); Examples include a cleaner (manufactured by Turbo Industries); a micro shifter (manufactured by Hadano Sangyo); and a circular vibrating sieve.
[0104]
Next, an image forming method and a process cartridge (hereinafter also referred to as “image forming method etc.”) of the present invention will be described.
[0105]
Examples of the image forming method of the present invention include the following methods. The image forming method of the present invention is an image forming method that includes a toner remaining amount detecting unit that can be attached to and detached from the image forming apparatus main body and can sequentially detect the remaining amount of toner according to a change in capacitance.
[0106]
Further, the image forming method of the present invention is detachable from the main body of the image forming apparatus, accommodates toner for developing the electrostatic latent image formed on the photoreceptor, and transports the toner to the photoreceptor. In a process cartridge having a toner storage portion provided with a developer carrier,
Static electricity between two upper and lower electrodes opposed to the developer carrying member and spaced apart (one of the two electrodes may be a developer carrying member or a developing blade sheet metal). An image forming method using a process cartridge capable of sequentially detecting the amount of toner in the toner storage unit by sequentially detecting a change in capacity.
[0107]
Further, the image forming method of the present invention is detachable from the main body of the image forming apparatus, accommodates toner for developing the electrostatic latent image formed on the photoconductor, and conveys the toner to the photoconductor. In a process cartridge having a toner storage portion provided with a developer carrying member of
The amount of toner in the toner storage unit is sequentially detected by sequentially detecting a change in capacitance of the electrostatic capacity generation unit disposed at a position where the contact area varies as the toner in the toner storage unit increases or decreases. An image forming method using a process cartridge that can be detected.
[0108]
The image forming method and process cartridge according to the present invention will be described in more detail with reference to the drawings. In the following description, an electrophotographic image forming apparatus in which a process cartridge is mounted is used. However, the image forming method of the present invention is an image forming method using a mechanism that detects the toner amount in the toner storage portion by electrostatic capacity. The image forming method is not particularly limited, and can be applied to other image forming methods such as an electrostatic recording method and a toner jet method.
[0109]
<Process cartridge type 1>
First, an embodiment of an electrophotographic image forming apparatus to which a process cartridge configured according to the present invention can be mounted will be described with reference to FIG. In this embodiment, the electrophotographic image forming apparatus is an electrophotographic laser beam printer A, and forms an image on a recording medium such as a recording paper, an OHP sheet, or a cloth by an electrophotographic image forming process. is there.
[0110]
The laser beam printer A has a drum-shaped electrophotographic photosensitive member, that is, a photosensitive drum 7. The photosensitive drum 7 is charged by a charging roller 8 which is a charging unit, and then irradiates a laser beam corresponding to image information from an optical unit 1 having a laser diode 1a, a polygon mirror 1b, a lens lc, and a reflection mirror 1d. As a result, a latent image corresponding to the image information is formed on the photosensitive drum 7. This latent image is developed by the developing means 9 to be a visible image, that is, a toner image.
[0111]
As shown in FIG. 2, the developing means 9 has a developing chamber 9A having a developing roller 9a as a developer carrying member, and a toner container as a toner storage portion formed adjacent to the developing chamber 9A. The developer in 11A is sent to the developing roller 9a in the developing chamber 9A by the rotation of the toner feeding member 9b. In the developing chamber 9A, a developer stirring member 9e is provided in the vicinity of the developing roller 9a, and the toner in the developing chamber is circulated. The developing roller 9a has a built-in fixed magnet 9c. When the developing roller 9a is rotated, the toner is conveyed, and a triboelectric charge is applied by the developing blade 9d, and a toner layer having a predetermined thickness is formed. The toner is supplied to the developing area of the photosensitive drum 7. The toner supplied to the developing area is transferred to a latent image on the photosensitive drum 7 to form a toner image. The developing roller 9a is connected to a developing bias circuit, and normally, a developing bias voltage in which a DC voltage is superimposed on an AC voltage is applied.
[0112]
On the other hand, the recording medium 2 set in the paper feed cassette 3a is conveyed to the transfer position by the pickup roller 3b, the conveyance roller pairs 3c and 3d, and the registration roller pair 3e in synchronization with the formation of the toner image. At the transfer position, a transfer roller 4 as transfer means is disposed, and a toner image on the photosensitive drum 7 is transferred to the recording medium 2 by applying a voltage.
[0113]
The recording medium 2 that has received the transfer of the toner image is conveyed to the fixing unit 5 by the conveyance guide 3f. The fixing unit 5 includes a driving roller 5c and a fixing roller 5b incorporating a heater 5a, and fixes the transferred toner image on the recording medium 2 by applying heat and pressure to the passing recording medium 2.
[0114]
The recording medium is conveyed by the discharge roller pairs 3g, 3h, and 3i, and discharged to the discharge tray 6 through the reverse path 3j. The discharge tray 6 is provided on the upper surface of the electrophotographic image forming apparatus main body 14 of the laser beam printer A. It is also possible to operate the swingable flapper 3k and discharge the recording medium 2 by the discharge roller pair 3m without passing through the reverse path 3j. In the present embodiment, the pickup means 3b, the conveyance roller pairs 3c, 3d, the registration roller pair 3e, the conveyance guide 3f, the discharge roller pairs 3g, 3h, 3i and the discharge roller pair 3m constitute the conveyance means 3.
[0115]
After the toner image is transferred onto the recording medium 2 by the transfer roller 4, the photosensitive drum 7 is subjected to the next image forming process after the toner remaining on the photosensitive drum 7 is removed by the cleaning means 10. The cleaning means 10 scrapes off the residual developer on the photosensitive drum 7 by an elastic cleaning blade 10a provided in contact with the photosensitive drum 7, and collects it in a waste toner reservoir 10b.
[0116]
Next, an example of the process cartridge B of this embodiment will be described. As shown in FIG. 2, a toner container (toner storage portion) 11A for storing toner, a frame 11 having a toner stirring / conveying member 9b as toner stirring means, and developing means such as a developing roller 9a and a developing blade 9d. A developing device is integrally formed by welding the developing frame 12 holding 9. The process cartridge B is formed into a cartridge by integrally connecting the developing device with a cleaning frame 13 attached with a cleaning means 10 such as a photosensitive drum 7 and a cleaning blade 10a and a charging roller 8.
[0117]
According to the present invention, the process cartridge B includes toner amount detection means (hereinafter also referred to as “toner amount detection device”) capable of sequentially detecting the remaining amount according to consumption of the toner in the toner container 11A. .
[0118]
According to the process cartridge configuration, as shown in FIG. 3, the toner amount detection device forms first and first recesses 80 that are open at the bottom so that the toner fed by the toner stirring / conveying member 9b can enter. Detection means such as the second electrodes 81 and 82 (hereinafter, the electrode used for the toner amount detection means may be referred to as “detection means”).
[0119]
Further, these electrodes 81 and 82 are arranged so as to be substantially opposed to and substantially parallel to the developing roller 9a. That is, the first electrode 81 and the second electrode 82 are disposed at different positions in the direction intersecting the moving direction of the toner T moved by the developer stirring / conveying member (stirring member) 9b. The first and second electrodes 81 and 82 are attached to the frame body 12 constituting the developing chamber 9. A more specific configuration of these electrodes 81 and 82 will be described in detail later.
[0120]
The toner amount detection device generates an electrical signal corresponding to the capacitance between the electrodes 81 and 82 by applying an alternating voltage to either the first electrode 81 or the second electrode 82. The amount of toner is detected by measuring it.
[0121]
Next, the movement and reduction state of toner when the process cartridge is mounted and used in the electrophotographic image forming apparatus main body 14 before shipment will be described.
[0122]
When the process cartridge is shipped, a seal member 30 for sealing the toner in the toner container 11 is attached between the developing chamber 9A and the toner container 11 as shown by a dotted line in FIG. The toner is prevented from leaking to the outside due to vibrations of time.
[0123]
When the user uses the process cartridge, the seal member 30 is removed and the process cartridge is mounted on the electrophotographic image forming apparatus main body 14. In recent years, there is also a configuration in which the seal member 30 is automatically removed after being mounted on the electrophotographic image forming apparatus main body 14.
[0124]
As described above, the toner agitating / conveying member 9b is provided in the toner container 11. The toner agitating / conveying member 9b is composed of the agitating shaft 9b1 and an elastic sheet (mylar) 9b2 attached to the agitating shaft 9b. The toner in the toner container 11 is conveyed to the developing chamber 9A side by the rotation.
[0125]
Due to the action of the toner agitating / conveying member 9b, the process cartridge B is used for the first time, and even immediately after the seal member 30 is removed, the toner is immediately sent to the developing chamber 9A side, so that printing can be performed smoothly. It becomes. At the same time, since the toner is sent between the first and second electrodes 81 and 82, the capacitance changes.
[0126]
The following four items can be given as the force for changing the state of the toner distributed in the vicinity of the first and second electrodes 81 and 82.
(1) An upward force when fed by the toner stirring / conveying member 9b.
(2) A force that drops downward due to the weight of the toner.
(3) A force to cover and fasten the toner in the recess 80. (If there is a large amount of toner below the recess 80, the "toner about to fall due to its own weight" will be covered.)
(4) A force to stay at the current position because the fluidity of the toner itself is low.
[0127]
When there is sufficient toner in the toner container 11 and the developing chamber 9A, the force of the item (1) is extremely large, and the force of the item (3) is firmly tightened by the force with which the concave portion 80 is covered. The state in which the toner is packed is maintained between the first and second electrodes 81 and 82, and in this case, the capacitance value continues to show a high value.
[0128]
If the process cartridge B is continuously used, the toner in the vicinity of the developing roller 9a is consumed and reduced for development, but the toner in the toner container 11 is always in the vicinity of the developing roller 9a by the action of the toner stirring / conveying member 9b. To be replenished. As a result, as the process cartridge B is used, the amount of toner in the toner container 11 decreases and its height decreases.
[0129]
As shown in FIG. 4, when the height of the toner in the toner container 11 decreases in the order of FIGS. 4 (a), (b), (c), and (d), the items (1) and (3) above. ), And the remaining amount of toner between the first and second electrodes 81 and 82 gradually decreases. As a result, the electrostatic capacity also changes.
[0130]
Referring to FIG. 4, FIG. 4A shows a state where the toner is sufficiently in the toner container 11 and the first and second electrodes 81 and 82 are buried in the toner. FIG. 4B shows a state in which the toner in the toner container 11 is reduced and the surface of the toner is at a height in contact with the lower end of the first electrode 81 and the upper end of the second electrode 82. FIG. 4C shows a state in which the toner is further reduced, is not already in the recess 80, is lower than the lower end of the first electrode 81, and is at the middle height of the second electrode 82. Yes. FIG. 4D shows a state where the height is finally in contact with the lower end of the second electrode 82.
[0131]
The tendency of changes in the toner height (remaining toner amount) and the capacitance value in the toner container 11 depends on the fluidity of the toner being used and the conveying ability of the toner stirring / conveying member 9b.
[0132]
For example, when the toner has fluidity such as water, the toner height in the toner container 11 and the toner height between the first and second electrodes 81 and 82 completely coincide with each other. As shown in FIGS. 4A to 4D, the fluidity is much lower than the fluidity of water, and the state of being conveyed to the developing chamber 9A side by the toner stirring / conveying member 9b is maintained to some extent. The toner height between the first and second electrodes 81 and 82 tends to change slightly after the change in the toner height in the toner container 11.
[0133]
Further, whether the toner agitating / conveying member 9b is too weak or too strong, the toner enters between the first and second electrodes 81 and 82, and the change in the remaining amount of toner and the capacitance value are changed. The relationship with change will be different.
[0134]
Therefore, it is necessary to optimize the positions and shapes of the first and second electrodes in accordance with the toner fluidity and the toner conveyance capability.
[0135]
In addition to the above configuration, for example, if the process cartridge is provided with a storage means, the number of printed sheets, the process cartridge drive time, etc. are stored, and detection is started only when a time longer than expected to reach an equilibrium state has elapsed. There is also a method.
[0136]
Further, in order to improve the detection accuracy when the toner amount is sequentially detected, the amount of change in capacitance may be increased. Specifically, this can be achieved by increasing the surface area of each of the first and second electrodes 81 and 82 or by reducing the distance between the first and second electrodes 81 and 82. When increasing the surface area of the electrode, it may be waved as shown in FIG. 5, or may be drawn as shown in FIG.
[0137]
If the electrode space cannot be secured or the cost must be reduced due to design reasons, either one of the first and second electrodes 81 and 82 is used as shown in FIGS. You may comprise by a round bar etc.
[0138]
Continuing the image formation, the consumption of toner advances, and finally, between the tip of the developing blade 9d that regulates the amount of toner on the surface of the developing roller 9a and the second electrode 82, that is, the developing roller 9a and the second electrode 82. When the toner is consumed, white spots occur on the image, resulting in a toner end, that is, no toner.
[0139]
At this time, the sheet metal of the developing roller 9a and the developing blade is further used as one of the electrodes of the capacitor (the pair is the second electrode 82), and as shown in FIG. 9, the first and second electrodes 81, 82 are used. By connecting the capacitor in parallel with the capacitor, white spot detection accuracy can be greatly improved.
[0140]
The graph of FIG. 10 schematically shows the detection accuracy when the developing roller 9a is used as one of the capacitors (FIG. 10B) and when it is not used (FIG. 10A). FIG. 10B shows that the amount of change in capacitance with respect to the unit toner change amount (consumption amount) immediately before blanking is dramatically larger than that in FIG. 10A.
[0141]
The amount of change in the electrostatic capacitance with respect to the unit toner change amount (consumption amount) immediately before the white spot increases dramatically as a result of the white spot starting to decrease the toner amount on the surface of the developing roller 9a as described above. Therefore, more accurate measurement of the amount of toner on the surface of the developing roller 9a is an essential condition for increasing detection accuracy.
[0142]
As described above, the “detection sensitivity” in the vicinity of the developing roller 9a is increased by using the developing roller 9a as one of the electrodes of the capacitor and the paired second electrode 82 is in the vicinity of the surface of the developing roller 9a. Thus, a difference in detection accuracy between FIGS. 10 (a) and 10 (b) occurs.
[0143]
Further, in order to increase the “detection sensitivity” near the white spots, it is necessary to increase the “detection sensitivity” near the surface of the developing roller 9a.
[0144]
Even if there is almost no toner on the surface of the developing roller 9a, as shown in FIG. 11, if the toner T is present in the region near the developing blade 9d, development is possible. Therefore, the toner T in the region can be detected with high sensitivity. Therefore, it is possible to improve white spot detection accuracy.
[0145]
However, by arranging the electrodes in the longitudinal direction as in the process cartridge form 1 of the present invention, a phenomenon of toner clogging between the two electrodes (or between the electrode and the developing sleeve / blade) is likely to occur. .
By using the toner as in the present invention, it is possible to prevent the toner from adhering to the electrodes, and clogging between the two electrodes does not occur, so that a good remaining toner detection accuracy can be obtained.
[0146]
The electrodes 81 and 82 all have the same function as long as they are conductive members. However, in the process cartridge form of the present invention, a non-magnetic SUS material or the like is used so as not to affect the toner circulation. Magnetic metal material is used.
[0147]
Further, if the electrodes 81 and 82 are directly subjected to processing such as vapor deposition and printing on the frame body 12 constituting the developing chamber 9A, or conductive resin is molded in two colors, the mounting tolerance is larger than that of electrodes made of different members. Since the component tolerance is reduced, the positional accuracy can be improved.
[0148]
In the above description, the toner amount detection configuration using magnetic toner as the toner has been described. However, the present invention can also be applied to a developing device configuration using non-magnetic toner.
[0149]
<Process cartridge type 2>
Next, a second process cartridge according to the present invention will be described with reference to FIGS.
[0150]
Also in the second process cartridge form, an electrophotographic image forming apparatus having the same configuration and operation as those described in the first process cartridge form is used, and the same members are denoted by the same reference numerals.
[0151]
In the second process cartridge form, as shown in FIG. 12, the electrode 84 is disposed on the bottom surface of the developing chamber 9A. That is, the electrode 84 is provided along a path where the toner T accommodated in the toner container 11 reaches the developing roller 9a. Therefore, this electrode 84 is hereinafter referred to as a path electrode 84. The path electrode 84 has the same shape for the entire region in the longitudinal direction in the cross-sectional shape shown in FIG.
[0152]
The magnetic toner in the vicinity of the bottom surface of the developing chamber 9A is always subjected to a force attracted to the developing roller 9a by the magnetic force of the magnet 9c disposed in the developing roller 9a. For this reason, when the amount of toner decreases and the supply of toner from the toner container 11 decreases, the toner near the floor surface of the developing chamber 9A tends to be consumed first.
[0153]
Specifically, as shown in FIG. 13, when the toner remaining in the toner container 11 is large, the toner in the developing chamber 9A is pushed in by its own weight, so that the toner is pushed in immediately even if the toner is consumed as described above ( In FIG. 13A, as the remaining amount of toner in the toner container 11 decreases, the force for pushing the consumed toner does not act strongly, and a cavity is formed near the bottom of the developing chamber 9A (FIG. 13A). 13 (b), (c)), and finally the toner remains around the tip of the developing blade 9d (FIG. 13 (d)).
[0154]
Since the toner is consumed in this way, according to this configuration, it is possible to detect the toner amount that can detect the toner amount near the bottom surface of the developing chamber 9A.
[0155]
The graph of FIG. 14 schematically shows changes in electrostatic capacity when the remaining amount of toner decreases. As shown in FIG. 14, it can be seen that the toner amount can be detected using this configuration.
[0156]
In the case of such a cartridge form, the toner remaining amount detection accuracy may be lowered due to the adhesion of the toner to the bottom surface or the side surface of the toner container, particularly in the vicinity of the toner remaining amount detecting means. According to this toner, adhesion to the bottom and side surfaces of the toner container is prevented, so that good toner remaining amount detection accuracy can be obtained.
[0157]
<Process cartridge form 3>
Next, a third process cartridge form of the present invention will be described.
[0158]
In the third process cartridge form, the toner amount detection device has a measurement electrode member 20A as a first capacitance generation unit for detecting the toner amount, as shown in FIG. At this time, it is preferable to have a reference electrode member 20B as a second capacitance generation unit which is a comparison member that detects the environment, that is, the temperature and humidity of the atmosphere, and outputs a reference signal.
[0159]
The measurement electrode member 20A is located at a position in contact with the toner, such as the inner side surface of the toner container 11A of the developing means 9 as shown in FIG. 15 or the inner bottom surface of the toner container 11A as shown in FIG. In addition, it is arranged in such a direction that the contact area with the toner varies as the toner decreases. Further, when the reference electrode member 20B is installed, as shown in FIG. 15, the reference electrode member 20B can be installed at an arbitrary position of the apparatus main body 14 that does not come into contact with the toner. For example, as shown in FIG. In addition, it can also be provided in the toner container 11A at a location that is partitioned by the partition wall 21 at a position opposite to the measurement electrode member 20A and does not contact the toner. Further, as shown in FIG. 18, when the measurement electrode member 20A and the reference electrode member 20B are integrally manufactured in a symmetrical arrangement, the reference electrode member 20B is bent outward so that the measurement electrode member 20A It can also be provided in the toner container on the same side as where it is placed, and at a location partitioned by the partition wall 21 and not in contact with the toner.
[0160]
As shown in FIG. 19, the measurement electrode member 20 </ b> A has a pair of conductive portions, that is, electrodes 23 and 24 formed in parallel on the substrate 22 at a predetermined interval. Each electrode 23, 24 can have one base and a plurality of branches branched from this base, and the branches of each electrode 23, 24 are formed alternately in parallel at regular intervals. be able to. In the present embodiment, the electrodes 23 and 24 have at least a pair of electrode portions 23a to 23f and 24a to 24f juxtaposed in parallel at a predetermined interval G, and the electrode portions 23a to 23f and 24a to 24f are connected to each other. The electrode portions 23g and 24g are connected to each other, and the two electrodes 23 and 24 have a large number of concave and convex shapes in which the branched portions are combined with each other. Of course, the electrode pattern of the measuring electrode member 20 is not limited to this, and a pair of electrodes 23 and 24 are formed in a spiral shape arranged in parallel with each other at a predetermined interval as shown in FIG. You can also.
[0161]
The measurement electrode member 20A can sequentially detect the remaining amount of toner in the toner container 11A by measuring the capacitance between the pair of parallel electrodes 23 and 24. That is, since the toner has a dielectric constant greater than that of air, the capacitance between the pair of electrodes 23 and 24 increases when the toner contacts the surface of the measurement electrode member 20A.
[0162]
Therefore, according to the present invention, by using the measurement electrode member 20A having the above-described configuration, by applying a predetermined calibration curve from the area of the toner in contact with the surface of the measurement electrode member 20A, the cross-sectional shape of the toner container 11A and the measurement electrode The amount of toner in the toner container 11A can be measured regardless of the shape of the member 20A.
[0163]
The electrode patterns 23 and 24 of the measurement electrode member 20A are, for example, a hard printed board 22 such as paper phenol or glass epoxy having a thickness of 0.4 to 1.6 mm, or a polyester or polyimide having a thickness of about 0.1 mm. It can be obtained by forming conductive metal patterns 23 and 24 such as copper on a flexible printed circuit board 22 by etching or printing, and is manufactured by the same method as a wiring pattern forming method for a normal printed circuit board. can do. Accordingly, even a complicated electrode pattern shape as shown in FIGS. 19 and 20 can be easily manufactured, and the manufacturing cost is almost the same as that of a simple pattern.
[0164]
Further, by using a complicated pattern shape as shown in FIGS. 19 and 20, the opposing length between the electrodes 23 and 24 can be increased, and further, by using a pattern formation method such as etching, the distance between the electrodes 23 and 24 can be increased. The predetermined gap G can be narrowed to about several tens of μm, and a large capacitance can be obtained. In addition, the amount of change in capacitance can be increased, and detection accuracy can be increased. Specifically, the electrodes 23 and 24 have a width of 0.1 to 0.5 mm, a thickness of 17.5 to 70 μm, and a gap G of 0.1 to 0.5 mm. Furthermore, the metal pattern forming surface can be laminated with a thin resin film of about 12.5 to 125 μm, for example.
[0165]
As described above, according to the toner amount detection device of the present invention, the change in the contact area of the toner with respect to the measurement electrode member 20A installed in the direction in which the developer on the side surface or the bottom surface of the toner container 11A decreases, that is, The change in the capacitance of the measurement electrode member 20A is measured, and the toner amount in the entire toner container is sequentially detected based on the value.
[0166]
That is, since the dielectric constant of the toner is larger than air, the portion where the developer is in contact with the measurement electrode member 20A (the portion where the toner is present) is output compared to the portion where the developer is not in contact (the portion where the toner is not present). Large capacitance. Therefore, the amount of developer in the toner container 11A can be estimated by measuring the change in capacitance.
[0167]
As shown in FIG. 15, by disposing the measurement electrode member 20A on the inner surface on one side of the toner container 11A, the ratio of the toner in the cross-sectional area of the YZ plane shown in FIG. It can be estimated from the value of electric capacity.
[0168]
Furthermore, by disposing the measurement electrode member 20A in two places on both side surfaces inside the developer container as shown in FIG. 22, when the process cartridge B is attached or detached by jam processing or the like as shown in FIG. Even when the toner is extremely biased in the longitudinal direction due to the inclination of the process cartridge B or the deviation of the print pattern, it is possible to estimate the bias of the toner by comparing the outputs of both electrode members 20A and 20A. In addition, the remaining amount of toner can be accurately estimated with respect to the deviation of the toner in the longitudinal direction as compared with the case where the toner is arranged on one side. However, when the toner of the present invention is used and a stirring mechanism is provided in the toner container, it is not always necessary to dispose the toner container in two places.
[0169]
In addition, as shown in FIG. 16, when the measurement electrode 20A is arranged on the bottom surface inside the toner container 11A, it is possible to estimate the ratio of the toner to the bottom area. Can be small. Further, since the toner container 11A has a larger bottom surface area than the side surface area, it is possible to increase the installation area of the toner amount detection member 20A compared to the case where the toner container 11A is disposed on the side surface, and the capacitance change. Since the amount can be increased and the output can be increased, the measurement error can be reduced.
[0170]
When the electrode members are arranged on the bottom surface and the side surface inside the toner container 11A, the toner amount in the toner container 11A can be estimated three-dimensionally, so the toner amount in the toner container is detected more accurately. be able to.
[0171]
According to the present invention, the toner remaining amount detection device may further include a reference electrode member 20B as a second capacitance generation unit as shown in FIG.
[0172]
The reference electrode member 20B has the same configuration as the measurement electrode member 20A. As shown in FIG. 19, the reference electrode member 20B is a pair of conductive portions formed in parallel with a predetermined gap G on the substrate 22, that is, the electrode 23 ( 23a to 23f) and 24 (24a to 24f), and the branched portions of the two electrodes 23 and 24 can be combined into a plurality of concave and convex shapes, or a spiral shape as shown in FIG. It can also be formed. The reference electrode member 20B can also be manufactured by the same method as a method for forming a wiring pattern on a normal printed board.
[0173]
According to the present invention, as described above, the reference electrode member 20B functions as a reference comparison member with respect to the measurement electrode member 20A because the capacitance fluctuates depending on environmental conditions such as temperature and humidity. The accuracy of remaining amount detection can be increased.
[0174]
In the case of such a process cartridge form, the toner remaining amount detecting means is installed as a planar electrostatic capacity generating portion on the side surface or the bottom surface, but toner adheres easily to such a portion, In particular, the electrostatic capacity may change due to the adhesion of toner between the electrodes on the substrate, making it difficult to detect the remaining amount of toner with high accuracy. However, according to the toner of the present invention, the adhesion is suppressed. Therefore, it is possible to achieve highly accurate toner remaining amount detection without causing such a problem.
[0175]
In the above-described process cartridge configuration, when the amount of toner stored in the container is initially 100%, the remaining amount of toner is sequentially detected over the entire region from about 30% to 0%. Can do. However, the present invention is not limited to this. For example, the detection may be sequentially performed over a region where the remaining amount of toner in the container is 50% to 0% or 40% to 0%. Good. Here, “the remaining amount of toner is 0%” does not mean that the toner is completely exhausted. For example, the remaining amount of toner of 0% includes that the remaining amount of toner is reduced to such an extent that a predetermined image quality (development quality) cannot be obtained even if the toner remains in the container.
[0176]
【Example】
Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited thereto.
[0177]
-Resin production example-
(Synthesis example of high molecular weight polymer)
Synthesis of high molecular weight polymer (H-1):
After adding 180 parts by mass of degassed water and 20 parts by mass of a 2% by weight aqueous solution of polyvinyl alcohol to a four-necked flask, 70 parts by mass of styrene, 20 parts by mass of acrylic acid-n-butyl, 10 parts by mass of monobutyl maleate, divinyl Add a mixed solution of 0.001 part by mass of benzene and 0.1 part by mass of 2,2-bis (4,4-di-tert-butylperoxycyclohexyl) propane (half-life 10 hours temperature 92 ° C.) And stirred to give a suspension.
[0178]
After sufficiently replacing the inside of the flask with nitrogen, the temperature was raised to 85 ° C. to initiate polymerization. After maintaining at the same temperature for 24 hours, 0.1 part by mass of benzoyl peroxide (half-life 10 hours temperature 92 ° C.) was added. Furthermore, the polymerization was completed by maintaining for 12 hours. This was separated, washed with water and dried to obtain a high molecular weight polymer (H-1).
[0179]
The high molecular weight polymer (H-1) was separated, washed with water, dried and analyzed, and the results were Mw = 900,000, PMw = 830,000, Mw / Mn = 2.3, Tg = 62 ° C. .
[0180]
Synthesis of high molecular weight polymer (H-2):
Into a four-necked flask, 300 parts by mass of xylene is charged, and the inside of the container is sufficiently replaced with nitrogen while stirring, and then heated to reflux.
[0181]
Under this reflux, 65 parts by mass of styrene, 30 parts by mass of acrylate-n-butyl, 5 parts by mass of monobutyl maleate, 0.001 part by mass of divinylbenzene, and 0.5 parts by mass of di-tert-butyl peroxide After dropping the mixed solution over 4 hours, the mixture was maintained for 2 hours to complete the polymerization, and a high molecular weight polymer (H-2) solution was obtained.
[0182]
A part of this polymer solution was sampled, dried under reduced pressure, and the obtained high molecular weight polymer (H-2) was analyzed. As a result, Mw = 230,000, PMw = 120,000, Mw / Mn = 2. 9. Tg = 55 ° C.
[0183]
(Synthesis example of low molecular weight polymer)
Synthesis of low molecular weight polymer (L-1):
Into a four-necked flask, 300 parts by mass of xylene is charged, and the inside of the container is sufficiently replaced with nitrogen while stirring, and then heated to reflux.
[0184]
Under this reflux, a mixture of 93 parts by mass of styrene, 7 parts by mass of acrylic acid-n-butyl and 3 parts by mass of di-tert-butyl peroxide was added dropwise over 4 hours, and then held for 2 hours to complete the polymerization. As a result, a low molecular weight polymer (L-1) solution was obtained.
[0185]
A part of this polymer solution was sampled, dried under reduced pressure, and the obtained low molecular weight polymer (L-1) was analyzed. As a result, Mw = 9800, PMw = 8000, Mw / Mn = 2. 3. Tg = 61.2 ° C.
[0186]
Synthesis of low molecular weight polymer (L-2):
Polymerization is performed in the same manner as the low molecular weight polymer (L-1) except that 96 parts by mass of styrene, 4 parts by mass of acrylic acid-n-butyl and 5 parts by mass of di-tert-butyl peroxide are used. A polymer (L-2) solution was obtained.
[0187]
A part of this polymer solution was sampled, dried under reduced pressure, and the obtained low molecular weight polymer (L-3) was analyzed. As a result, Mw = 6900, PMw = 5900, Mw / Mn = 2. 1 and Tg = 59.3 ° C.
[0188]
Synthesis of low molecular weight polymer (L-3):
Polymerization is performed in the same manner as the low molecular weight polymer (L-1) except that 100 parts by mass of styrene and 9 parts by mass of di-tert-butyl peroxide are used to obtain a low molecular weight polymer (L-2) solution. It was.
[0189]
A part of this polymer solution was sampled, dried under reduced pressure, and the obtained low molecular weight polymer (L-2) was analyzed. As a result, Mw = 4300, PMw = 4000, Mw / Mn = 2. 4. Tg = 60 ° C.
[0190]
Synthesis of low molecular weight polymer (L-4):
Polymerization is carried out in the same manner as the low molecular weight polymer (L-1) except that 86 parts by mass of styrene, 14 parts by mass of acrylic acid-n-butyl and 2 parts by mass of di-tert-butyl peroxide are used. A polymer (L-4) solution was obtained.
[0191]
A part of this polymer solution was sampled, dried under reduced pressure, and the obtained low molecular weight polymer (L-4) was analyzed. As a result, Mw = 20300, PMw = 18000, Mw / Mn = 2. 3. Tg = 67.6 ° C.
[0192]
Synthesis of low molecular weight polymer (L-5):
Polymerization is carried out in the same manner as the low molecular weight polymer (L-1) except that 75 parts by mass of styrene, 25 parts by mass of acrylic acid-n-butyl, and 1.5 parts by mass of di-tert-butyl peroxide are used. A low molecular weight polymer (L-5) solution was obtained.
[0193]
A part of this polymer solution was sampled, dried under reduced pressure, and the obtained low molecular weight polymer (L-5) was analyzed. As a result, Mw = 37000, PMw = 30200, Mw / Mn = 2. 3. Tg = 51.1 ° C.
[0194]
Next, the high molecular weight polymer and the low molecular weight polymer were mixed at a ratio as shown in Table 1. In the method, xylene was added to 100 parts by mass of xylene so that the total of the high molecular weight polymer and the low molecular weight polymer was 100 parts by mass, the temperature was raised, the mixture was stirred under reflux, held for 12 hours, and then the organic solvent The resin obtained was cooled, solidified, and then pulverized to obtain a resin composition for toner.
[0195]
<Example 1>
The resin component and the wax component were formulated as shown in Table 1, and a toner was obtained as follows.
[0196]
-100 parts by mass of toner resin composition shown in Table 1
・ Spherical magnetic iron oxide (average particle size 0.20μm ・ BET8.5m²/ G) 100 parts by mass
・ Monoazo iron complex 2 parts by mass
・ 3 parts by mass of polypropylene (DSC endothermic peak 140 ° C.)
The above mixture is premixed with a Henschel mixer, melt-kneaded with a twin-screw extruder heated to 130 ° C., the cooled kneaded product is coarsely pulverized with a hammer mill, and finely pulverized with a pulverizer (jet mill) using a jet stream. The finely pulverized product obtained is pulverized, and the finely divided powder, ultrafine powder, and coarse powder are strictly classified and removed at the same time using a multi-division classifier (Nippon Mining Co., Ltd. elbow jet classifier) using the Coanda effect. Diameter (D_Four) 6.7 μm negatively chargeable toner particles were obtained.
[0197]
100 parts of the magnetic toner particles and 1.2 parts of hydrophobic silica fine powder treated with dimethyldichlorosilane, then with hexamethyldisilazane and then with dimethylsilicone oil were mixed with a Henschel mixer to be negatively charged. Toner 1 was prepared. The analysis results of this toner are shown in Table 1.
[0198]
  <Example 24. Reference Example 1Comparative Examples 1 to 3>
  In the same manner as in Example 1, based on the toner formulation in Table 1, Examples 2 to4. Reference Example 1The toners of Comparative Examples 1 to 3 were obtained. The analysis results of these toners are shown in Table 1.
[0199]
Next, the prepared toner was evaluated by the following method. The evaluation results are shown in Table 2.
[0200]
The EP-72 cartridge provided with the toner remaining amount detecting means capable of sequentially detecting the remaining amount of toner shown in the process cartridge form 1 was modified so that 1600 g of the toner could be filled. The Canon laser beam printer LBP-950 has been modified so that the cartridge can be inserted and the toner remaining amount detection signal can be detected. Further, the A4 landscape feed has been modified from 32 sheets / minute to 50 sheets / minute, and the fixing device. The total pressure between the heating roller and the pressure roller was set to 333 N (34 kg), and the nip was set to 9 mm. The process speed at this time was 235 mm / sec.
[0201]
Under the above setting conditions, 2 sheets / 6 sec. In a high temperature and high humidity environment (30 ° C., 85% RH) and in a low temperature and low humidity environment (15 ° C., 10% RH). An image printing test of 30000 sheets was performed at the intermittent printing speed of, and the obtained images were evaluated for the following items. Further, in a high-temperature and high-humidity environment, after a 15,000-sheet image printing test, the sample was left in the same environment for 2 days, and a further 15,000-sheet image printing test was performed.
[0202]
(1) Image density
Ordinary paper for ordinary copying machines (75 g / m²), 30000 printouts, in a high temperature and high humidity environment (temperature 30 ° C, humidity 85% RH), the image density at the end of the morning and after the end of 2 days, and in a low temperature and low humidity environment (temperature 15 ° C, humidity 10%) In (RH), the image density at the end of durability was evaluated. For the image density, a “Macbeth reflection densitometer” (manufactured by Macbeth) was used to measure a relative density with respect to a printout image of a white background portion having a document density of 0.00.
[0203]
(2) fog
Ordinary paper for ordinary copying machines (75 g / m²), 30000 sheets were printed out under low temperature and low humidity (temperature 15 ° C., humidity 10% RH), and fogging at the start and end was evaluated. The fog was calculated from a comparison between the whiteness of the transfer paper measured by a reflectometer (manufactured by Tokyo Denshoku Co., Ltd.) and the whiteness of the transfer paper after printing solid white.
[0204]
(3) Remaining toner detection accuracy
Ordinary paper for ordinary copying machines (75 g / m²) In a high-temperature and high-humidity environment (30 ° C., 85% RH), and toner at the time when the remaining amount of toner is 10% detected (equivalent to 165 g) and 5% detected (equivalent to 82.5 g). The remaining amount detection error was obtained by measuring the remaining amount and comparing it with the value of the output signal from the remaining amount detecting device.
Remaining amount detection error (%) = {| (actually remaining amount) − (remaining amount detected value) | / (actually remaining amount)} × 100
[0205]
(4) Image quality
In a normal environment (23 ° C., 60% RH), the checker pattern shown in FIG. 24 was printed out, and the dot reproducibility was evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: Very good (less than 2 defects / 100)
○: Good (3-5 defects / 100 defects)
Δ: Normal (6-10 / 100 defects)
×: Bad (11 or more defects / 100)
[0206]
(5) Fading
In a high-temperature and high-humidity environment (30 ° C, 85% RH), while taking a solid black image every 1000 sheets, a 4% print pattern was printed at an endurance of 30,000 sheets at a rate of 2/6 seconds. The uniformity of the solid black image was checked for fading.
[0207]
[Table 1]

[0208]
[Table 2]

[0209]
【The invention's effect】
Toners and images that maintain high developability in long-term use even in harsh environments such as high temperature, high humidity, and low temperature and low humidity, accurately detect the remaining amount of toner, and do not cause image effects such as fading. A forming method and a process cartridge can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of an electrophotographic image forming apparatus according to the present invention.
FIG. 2 is a longitudinal sectional view showing a longitudinal section in an embodiment of a process cartridge according to the present invention.
FIG. 3 is a diagram showing the arrangement and recesses of first and second electrodes in a toner amount detection device according to the present invention.
FIG. 4 is a diagram illustrating a positional relationship between a first toner electrode and a second electrode when toner is consumed.
FIG. 5 is a perspective view showing an embodiment of first and second electrodes.
FIG. 6 is a perspective view showing another embodiment of the first and second electrodes.
FIG. 7 is a longitudinal sectional view of an embodiment of a process cartridge according to the present invention.
FIG. 8 is a longitudinal sectional view of an embodiment of a process cartridge according to the present invention.
FIG. 9 is a diagram showing an embodiment of an electric circuit of the first and second electrodes and the developing roller.
FIGS. 10A and 10B are graphs showing transitions of toner amount and electrostatic capacity, respectively, when (a) the developing member is not used as a capacitor and (b) when the developing member is used as a capacitor.
FIG. 11 is an explanatory diagram showing a state where toner is present only in the vicinity of the developing blade.
FIG. 12 is a longitudinal sectional view of an essential part showing another embodiment of the toner amount detection device.
FIG. 13 is an explanatory diagram illustrating a state of a bottom electrode and toner when the toner amount detection device in the developing chamber is decreasing.
14 is a diagram illustrating a relationship between a toner amount and a capacitance in the toner amount detection apparatus of FIG.
FIG. 15 is a perspective view of a toner container for explaining an example of a toner amount detection device used in the present invention.
FIG. 16 is a perspective view of a toner container for explaining another example of the toner amount detection device used in the present invention.
FIG. 17 is a perspective view of a toner container for explaining another example of the toner amount detection device used in the present invention.
FIG. 18 is a perspective view of a toner container for explaining another example of the toner amount detection device used in the present invention.
FIG. 19 is a front view showing an example of a measurement electrode member and a reference electrode member.
FIG. 20 is a front view showing another example of the measurement electrode member and the reference electrode member.
FIG. 21 is a diagram illustrating an example of a toner storage mode in a toner container.
FIG. 22 is a perspective view of a toner container for explaining another example of the toner amount detection device used in the present invention.
FIG. 23 is a diagram illustrating another example of a toner accommodation mode in a toner container.
FIG. 24 is an explanatory diagram of a checker pattern used for evaluation of dot reproducibility.
[Explanation of symbols]
1 Optical means
1a Laser diode
1b Polygon mirror
1c lens
1d reflection mirror
2 recording media
3, 63 Conveying means
3a Paper cassette
3b Pickup roller
3c, 3d Carrying roller pair
3e Registration roller pair
3f Transport guide
3g, 3h, 3i, 3m discharge roller pair
3j reverse path
4 Transfer roller
5 Fixing means
5a heater
5b Fixing roller
5c Drive roller
6 Discharge tray
7, 51 Photosensitive drum (electrophotographic photosensitive member)
8 Charging roller (charging means)
9 Development means
9A Development chamber
9a Development roller
9b Toner feeding member
9c fixed magnet
9d Development blade
9e Toner stirring member
9h electrode rod
10 Cleaning means
10a Cleaning blade
10b Waste toner reservoir
11 Frame
11A Toner container (toner container)
12 Development frame
13 Cleaning frame
20A measurement electrode member (first capacitance generating part)
20B reference electrode member (second capacitance generating part)
21 partition wall
22 Substrate
23, 24 electrodes
23a-23f, 24a-24f Electrode part
23g, 24g Connecting electrode part
80 recess
81 First electrode
82 Second electrode
84 Path electrode
A Laser beam printer
B Process cartridge
G interval

Claims (15)

A toner used in an image forming method using a process cartridge that is detachable from an image forming apparatus main body and includes a toner remaining amount detecting unit capable of sequentially detecting a remaining amount of toner according to a change in capacitance.
The toner contains at least a binder resin and a wax component, and has a molecular weight distribution of 3 × 10 ^{3 to} 3 × in the molecular weight distribution measured by gel permeation chromatography (GPC) of the tetrahydrofuran (THF) soluble matter of the toner. A temperature rise measured by a differential scanning calorimeter (DSC) of the toner having a main peak in a region of 10 ⁴ and a sub-peak or shoulder in a region of a molecular weight of 5 × 10 ^{4 to} 3 × 10 ⁶ in the DSC curve of the time, it has at least one endothermic peak in the temperature region of 120 to 160 ° C.,
The toner binder resin has at least a low molecular component (L component) having a maximum value in the region of molecular weight 3 × 10 ^{3 to} 3 × 10 ⁴ measured by GPC of THF soluble component, and molecular weight 5 ×. It is composed of a mixture of polymer side components having a maximum value in a region of 10 ^{4 to} 3 × 10 ⁶ , and the ratio of styrene to the constituent monomer of L component is 90 to 100% by mass. Toner. The process cartridge includes a toner storage unit that stores toner for developing the electrostatic latent image formed on the photosensitive member and includes a developer carrier for transporting the toner to the photosensitive member. ,
A process capable of sequentially detecting the amount of toner in the toner storage unit by sequentially detecting a change in capacitance between two upper and lower electrodes arranged opposite to each other and facing the developer carrier. The toner according to claim 1, wherein the toner is a cartridge.   The toner according to claim 2, wherein one of the two electrodes is a developer carrying member or a developing blade sheet metal. The process cartridge includes a toner storage unit that stores toner for developing the electrostatic latent image formed on the photosensitive member and includes a developer carrier for transporting the toner to the photosensitive member. ,
The amount of toner in the toner storage unit is sequentially detected by sequentially detecting the change in capacitance of the electrostatic capacity generation unit arranged at a position where the contact area varies as the toner in the toner storage unit increases or decreases. The toner according to claim 1, wherein the toner is a process cartridge capable of being detected.   The toner according to any one of claims 1 to 4, wherein the proportion of styrene in the constituent monomer of the binder resin of the toner is 80 to 99 mass%. An image forming method using a process cartridge that is detachable from an image forming apparatus main body and includes a toner remaining amount detecting unit capable of sequentially detecting a remaining amount of toner according to a change in capacitance.
The toner contains at least a binder resin and a wax component, and has a main peak in a molecular weight region of 3 × 10 ^{3 to} 3 × 10 ⁴ in a molecular weight distribution measured by GPC of a THF soluble part of the toner. And at least one in the temperature range of 120 to 160 ° C. in the DSC curve at the time of temperature rise measured by DSC of the toner having a sub-peak or shoulder in the molecular weight range of 5 × 10 ^{4 to} 3 × 10 ⁶ . It has a endothermic peak,
The toner binder resin has at least a low molecular component (L component) having a maximum value in the region of molecular weight of 3 × 10 ^{3 to} 3 × 10 ⁴ measured by GPC of THF soluble component, and molecular weight of 5 ×. It is composed of a mixture of polymer side components having a maximum value in a region of 10 ^{4 to} 3 × 10 ⁶ , and the ratio of styrene to the constituent monomer of L component is 90 to 100% by mass. Image forming method. The process cartridge includes a toner storage unit that stores toner for developing the electrostatic latent image formed on the photosensitive member and includes a developer carrier for transporting the toner to the photosensitive member. ,
Process capable of sequentially detecting the amount of toner in the toner storage unit by sequentially detecting a change in electrostatic capacity between two upper and lower electrodes which are opposed to the developer carrying member and spaced apart from each other. The image forming method according to claim 6 , wherein the image forming method is a cartridge. The image forming method according to claim 7 , wherein one of the two electrodes is a developer carrying member or a developing blade sheet metal. The process cartridge includes a toner storage unit that stores toner for developing the electrostatic latent image formed on the photosensitive member and includes a developer carrier for transporting the toner to the photosensitive member. ,
The amount of toner in the toner storage unit is sequentially detected by sequentially detecting the change in capacitance of the electrostatic capacity generation unit arranged at a position where the contact area varies with the increase or decrease of the toner in the toner storage unit. 7. The image forming method according to claim 6 , wherein the image forming method is a process cartridge capable of being detected. The image forming method according to any one of claims 6 to 9 ratio of styrene to total construction in the monomer of the binder resin of the toner is characterized in that it is a 80 to 99 wt%. In a process cartridge provided with a toner remaining amount detecting means that can be attached to and detached from the image forming apparatus main body and can detect the remaining amount of toner sequentially according to a change in capacitance.
The toner used contains at least a binder resin and a wax component, and has a main peak in the molecular weight region of 3 × 10 ^{3 to} 3 × 10 ⁴ in the molecular weight distribution measured by GPC of the THF soluble part of the toner. And has a sub-peak or shoulder in a molecular weight region of 5 × 10 ^{4 to} 3 × 10 ⁶ , and in a DSC curve at the time of temperature rise measured by DSC of the toner, at least in a temperature region of 120 to 160 ° C. It has a single endothermic peak,
The toner binder resin has at least a low molecular component (L component) having a maximum value in the region of molecular weight of 3 × 10 ^{3 to} 3 × 10 ⁴ measured by GPC of THF soluble component, and molecular weight of 5 ×. It is composed of a mixture of polymer side components having a maximum value in a region of 10 ^{4 to} 3 × 10 ⁶ , and the ratio of styrene to the constituent monomer of L component is 90 to 100% by mass. To process cartridge. The process cartridge includes a toner storage unit that stores toner for developing the electrostatic latent image formed on the photosensitive member and includes a developer carrier for transporting the toner to the photosensitive member. ,
It is possible to sequentially detect the amount of toner in the toner storage unit by sequentially detecting a change in capacitance between two upper and lower electrodes that are opposed to the developer carrying member and spaced apart from each other. The process cartridge according to claim 11 , wherein 13. The process cartridge according to claim 12 , wherein one of the two electrodes is a developer carrying member or a developing blade sheet metal. The process cartridge includes a toner storage unit that stores toner for developing the electrostatic latent image formed on the photosensitive member and includes a developer carrier for transporting the toner to the photosensitive member. ,
The amount of toner in the toner storage unit is sequentially detected by sequentially detecting the change in capacitance of the electrostatic capacity generation unit arranged at a position where the contact area varies as the toner in the toner storage unit increases or decreases. The process cartridge according to claim 11 , wherein the process cartridge can be detected. The process cartridge according to any one of claims 11 to 14 , wherein a ratio of styrene to a constituent monomer of the binder resin of the toner is 80 to 99 mass%.

Images