JP4472903B2 - Toner for electrophotography, developer and image forming method - Google Patents

Description

【００４４】
そして、トナーの流動特性、帯電特性等を改善する目的でトナー粒子と各種金属酸化物等の無機粉末等を混合して使用する方法が提案されており、これら無機粉末等は外添剤と呼ばれている。また必要に応じて該無機粉末表面の疎水性、帯電特性等を改質する目的で特定のシランカップリング剤、チタネートカップリング剤、シリコーンオイル、有機酸等で処理する方法、特定の樹脂を被覆する方法等も提案されている。前記無機粉末としては、例えば、二酸化珪素（シリカ）、二酸化チタン（チタニア）、酸化アルミニウム、酸化亜鉛、酸化マグネシウム、酸化セリウム、酸化鉄、酸化銅、酸化錫等が知られている。特にシリカや酸化チタン微粒子とジメチルジクロロシラン、ヘキサメチルジシラザン、シリコーンオイル等の有機珪素化合物とを反応させシリカ微粒子表面のシラノール基を有機基で置換し疎水化したシリカ微粒子が用いられている。
【００４５】
また、トナー粒子の体積平均粒径が４〜９μｍであり、体積平均径Ｄｖと個数平均径Ｄｎの比、Ｄｖ／Ｄｎが１．５以下であることが好ましく、これにより初期画像品質との差異が少なくなる。
【００４６】
本発明の電子写真用トナーは、一成分現像剤としても提供でき、キャリアと混合して二成分現像剤としても提供できる。本発明のトナーはどちらの現像剤に用いても、長期間使用後もトナーの帯電量及び搬送量の安定、高画像品質、機内汚染や感光体フィルミング防止といった効果がある。さらに、本発明はそれら現像剤を封入した容器として提供してもよいし、画像形成装置として提供してもよい。
【００４７】
本発明のトナーを二成分現像剤として用いる場合、キャリアとしては、アクリル樹脂、フッ素樹脂、シリコ−ン樹脂等のコーティング剤として用いたキャリア等が知られているがシリコンコートキャリアが現像剤寿命の観点から優れている。
【００４８】
また、本発明により、潜像保持体上に潜像を形成する潜像形成工程、該潜像を現像剤担持体上の現像剤を用いて現像する現像工程、現像されたトナー像を転写体上に転写する転写工程、転写体上のトナー像を加熱定着する定着工程を有する画像形成方法において、現像剤として、本発明の一成分現像剤又は二成分現像剤をを用いることを特徴とする画像形成方法が提供される。
【００４９】
また、本発明により、上記の画像形成方法であって、さらに現像工程が、現像剤担持体上に現像剤の薄層を形成し、潜像保持体と接触又は非接触で現像することを特徴とする画像形成方法が提供される。
【００５０】
さらに、上記の一成分現像剤を用いる画像形成方法であって、前記潜像形成工程において、形成される潜像が多色に分割された静電潜像であり、かつ、前記潜像保持体が該静電潜像の色にそれぞれ対応した複数の潜像保持体であり、前記現像工程において、前記現像剤が静電潜像の色にそれぞれ対応した複数の現像剤であり、かつ、静電潜像を、該複数の現像剤にそれぞれ対応した複数の潜像保持体上に、現像剤担持体及び該現像剤担持体上に供給する現像剤の層厚を均一に規制する現像ブレードを備えた複数の多色現像装置を用いて現像し、前記転写工程において、複数の潜像保持体表面に前記転写体を当接し転写手段によって、現像されたトナー像を該転写体に順次静電転写することを特徴とする画像形成方が提供される。
【００５１】
さらに、上記の二成分現像剤を用いる画像形成方法であって、前記潜像形成工程において、形成される潜像が多色に分割された静電潜像であり、かつ、前記潜像保持体が該静電潜像の色にそれぞれ対応した複数の潜像保持体であり、前記現像工程において、前記現像剤が静電潜像の色にそれぞれ対応した複数の現像剤であり、かつ、静電潜像を、該複数の現像剤にそれぞれ対応した複数の潜像保持体上に、現像ロール及び該現像ロール上に供給する現像剤の層厚を均一に規制する現像ブレードを備えた複数の多色現像装置を用いて現像し、前記転写工程において、複数の潜像保持体表面に前記転写体を当接し転写手段によって、現像されたトナー像を該転写体に順次静電転写することを特徴とする画像形成方法が提供される。
【００５２】
着色剤としては公知の染料及び顔料が全て使用でき、例えば、カーボンブラック、ニグロシン染料、鉄黒、ナフトールイエローＳ、ハンザイエロー（１０Ｇ、５Ｇ、Ｇ）、カドミウムイエロー、黄色酸化鉄、黄土、黄鉛、チタン黄、ポリアゾイエロー、オイルイエロー、ハンザイエロー（ＧＲ、Ａ、ＲＮ、Ｒ）、ピグメントイエローＬ、ベンジジンイエロー（Ｇ、ＧＲ）、パーマネントイエロー（ＮＣＧ）、バルカンファストイエロー（５Ｇ、Ｒ）、タートラジンレーキ、キノリンイエローレーキ、アンスラザンイエローＢＧＬ、イソインドリノンイエロー、ベンガラ、鉛丹、鉛朱、カドミウムレッド、カドミウムマーキュリレッド、アンチモン朱、パーマネントレッド４Ｒ、パラレッド、ファイセーレッド、パラクロルオルトニトロアニリンレッド、リソールファストスカーレットＧ、ブリリアントファストスカーレット、ブリリアントカーミンＢＳ、パーマネントレッド（Ｆ２Ｒ、Ｆ４Ｒ、ＦＲＬ、ＦＲＬＬ、Ｆ４ＲＨ）、ファストスカーレットＶＤ、ベルカンファストルビンＢ、ブリリアントスカーレットＧ、リソールルビンＧＸ、パーマネントレッドＦ５Ｒ、ブリリアントカーミン６Ｂ、ポグメントスカーレット３Ｂ、ボルドー５Ｂ、トルイジンマルーン、パーマネントボルドーＦ２Ｋ、ヘリオボルドーＢＬ、ボルドー１０Ｂ、ボンマルーンライト、ボンマルーンメジアム、エオシンレーキ、ローダミンレーキＢ、ローダミンレーキＹ、アリザリンレーキ、チオインジゴレッドＢ、チオインジゴマルーン、オイルレッド、キナクリドンレッド、ピラゾロンレッド、ポリアゾレッド、クロームバーミリオン、ベンジジンオレンジ、ペリノンオレンジ、オイルオレンジ、コバルトブルー、セルリアンブルー、アルカリブルーレーキ、ピーコックブルーレーキ、ビクトリアブルーレーキ、無金属フタロシアニンブルー、フタロシアニンブルー、ファストスカイブルー、インダンスレンブルー（ＲＳ、ＢＣ）、インジゴ、群青、紺青、アントラキノンブルー、ファストバイオレットＢ、メチルバイオレットレーキ、コバルト紫、マンガン紫、ジオキサンバイオレット、アントラキノンバイオレット、クロムグリーン、ジンクグリーン、酸化クロム、ピリジアン、エメラルドグリーン、ピグメントグリーンＢ、ナフトールグリーンＢ、グリーンゴールド、アシッドグリーンレーキ、マラカイトグリーンレーキ、フタロシアニングリーン、アントラキノングリーン、酸化チタン、亜鉛華、リトポン及びそれらの混合物が使用できる。使用量は一般にバインダー樹脂１００重量部に対し０．１〜５０重量部である。
【００５３】
製造される現像剤に離型性を持たせる為に、製造される現像剤の中にワックスを含有させることが好ましい。ワックスは、その融点が４０〜１２０℃のものであり、特に５０〜１１０℃のものであることが好ましい。ワックスの融点が過大のときには低温での定着性が不足する場合があり、一方融点が過小のときには耐オフセット性、耐久性が低下する場合がある。なお、ワックスの融点は、示差走査熱量測定法（ＤＳＣ）によって求めることができる。すなわち、数ｍｇの試料を一定の昇温速度、例えば（１０℃／ｍｉｎ）で加熟したときの融解ピーク値を融点とする。
【００５４】
本発明に用いることができるワックスとしては、例えば固形のパラフィンワックス、マイクロワックス、ライスワックス、脂肪酸アミド系ワックス、脂肪酸系ワックス、脂肪族モノケトン類、脂肪酸金属塩系ワックス、脂肪酸エステル系ワックス、部分ケン化脂肪酸エステル系ワックス、シリコーンワニス、高級アルコール、カルナウバワックス等を挙げることができる。また低分子量ポリエチレン、ポリプロピレン等のポリオレフィン等も用いることができる。特に、環球法による軟化点が７０〜１５０℃のポリオレフィンが好ましく、さらには当該軟化点が１２０〜１５０℃のポリオレフィンが好ましい。ワックスの使用量は、一般に結着樹脂１００重量部に対して０．５〜２０重量部である。
【００５５】
感光体や一次転写媒体に残存する転写後の現像剤を除去するためのクリーニング性向上剤としては、例えばステアリン酸亜鉛、ステアリン酸カルシウム、ステアリン酸等の脂肪酸金属塩、例えばポリメチルメタクリレート微粒子、ポリスチレン微粒子等のソープフリー乳化重合等によって製造された、ポリマー微粒子等を挙げることかできる。ポリマー微粒子は比較的粒度分布が狭く、体積平均粒径が０．０１〜１μｍのものが好ましい。
【００５６】
【発明の実施の形態】
以下に、本発明の電子写真用トナーの製造方法及び本発明のトナーを用いたフルカラー画像形成方法について説明する。
【００５７】
（トナーの製造方法）
本発明の電子写真用トナーの製造方法は、少なくとも結着剤樹脂、帯電制御剤及び着色剤を含む現像剤成分を機械的に混合する工程と、溶融混練する工程と、粉砕する工程と、分級する工程とを有する製造方法が適用できる。また機械的に混合する工程や溶融混練する工程において、粉砕又は分級する工程で得られる製品となる粒子以外の粉末を戻して再利用する製造方法も含まれる。
【００５８】
ここで言う製品となる粒子以外の粉末（副製品）とは溶融混練する工程後、粉砕工程で得られる所望の粒径の製品となる成分以外の微粒子や粗粒子や引き続いて行われる分級工程で発生する所望の粒径の製品となる成分以外の微粒子や粗粒子を意味する。このような副製品を混合工程や溶融混練する工程で原料と好ましくは副製品１に対しその他原材料９９から副製品５０に対し、その他原材料５０の重量比率で混合する。
【００５９】
結着剤樹脂、帯電制御剤、着色剤及び副製品を含む現像剤成分を機械的に混合する混合工程は、回転させる羽による通常の混合機等を用いて通常の条件で行えばよく、特に制限はない。
【００６０】
以上の混合工程が終了したら、次いで混合物を混練機に仕込んで溶融混練する。溶融混練機としては、分散粒子径を適当な範囲にするため上述したように一軸、二軸の連続混練機や、ロールミルによるバッチ式混練機を用いることができる。例えば、神戸製鋼所社製ＫＴＫ型二軸押出機、東芝機械社製ＴＥＭ型押出機、ケイ・シー・ケイ社製二軸押出機、池貝鉄工所社製ＰＣＭ型二軸押出機、ブス社製コニーダー等が好適に用いられる。この溶融混練は、バインダー樹脂の分子鎖の切断を招来しないような適正な条件で行うことが重要である。具体的には、溶融混練温度は、結着剤樹脂の軟化点を参考に行うべきであり、軟化点より低温過ぎると切断が激しく、高温過ぎると分散が進まない。
【００６１】
以上の溶融混練工程が終了したら、次いで混練物を粉砕する。この粉砕工程においては、まず粗粉砕し、次いで微粉砕することが好ましい。この際、ジェット気流中で衝突板に衝突させて粉砕したり、ジェット気流中で粒子同士を衝突させて粉砕したり、機械的に回転するローターとステーターの狭いギャップで粉砕する方式が好ましく用いられる。
【００６２】
この粉砕工程が終了した後に、粉砕物を遠心力等で気流中で分級し、もって所定の粒径例えば平均粒径が５〜２０μｍのトナーを製造する。
また、トナーを調製する際には、現像剤の流動性や保存性、現像性、転写性を高めるために、以上のようにして製造されたトナーにさらに先に挙げた疎水性シリカ微粉末等の無機微粒子を添加混合してもよい。外添剤の混合は一般の粉体の混合機が用いられるがジャケット等装備して、内部の温度を調節できることが好ましい。外添剤に与える負荷の履歴を変えるには、途中又は漸次外添剤を加えていけばよい。もちろん混合機の回転数、転動速度、時間、温度等を変化させてもよい。はじめに強い負荷を、次に比較的弱い負荷を与えてもよいし、その逆でもよい。使用できる混合設備の例としては、Ｖ型混合機、ロッキングミキサー、レーディゲミキサー、ナウターミキサー、ヘンシェルミキサー等が挙げられる。
【００６３】
また、本発明のトナーを二成分系現像剤に用いる場合には、磁性キャリアと混合して用いればよく、現像剤中のキャリアとトナーの含有比は、キャリア１００重量部に対してトナー１〜１０重量部が好ましい。磁性キャリアとしては、粒子径２０〜２００μｍ程度の鉄粉、フェライト粉、マグネタイト粉、磁性樹脂キャリア等従来から公知のものが使用できる。
【００６４】
また、キャリアの被覆材料としては、アミノ系樹脂、例えば尿素−ホルムアルデヒド樹脂、メラミン樹脂、ベンゾグアナミン樹脂、ユリア樹脂、ポリアミド樹脂、エポキシ樹脂等があげられる。またポリビニル及びポリビニリデン系樹脂、例えばアクリル樹脂、ポリメチルメタクリレート樹脂、ポリアクリロニトリル樹脂、ポリ酢酸ビニル樹脂、ポリビニルアルコール樹脂、ポリビニルブチラール樹脂、ポリスチレン樹脂及びスチレンアクリル共重合樹脂等のポリスチレン系樹脂、ポリ塩化ビニル等のハロゲン化オレフィン樹脂、ポリエチレンテレフタレート樹脂及びポリブチレンテレフタレート樹脂等のポリエステル系樹脂、ポリカーボネート系樹脂、ポリエチレン樹脂、ポリ弗化ビニル樹脂、ポリ弗化ビニリデン樹脂、ポリトリフルオロエチレン樹脂、ポリヘキサフルオロプロピレン樹脂、弗化ビニリデンとアクリル単量体との共重合体、弗化ビニリデンと弗化ビニルとの共重合体、テトラフルオロエチレンと弗化ビニリデンと非弗化単量体とのターポリマー等のフルオロターポリマー等が使用できるが、現像剤寿命の観点からシリコン樹脂が優れている。
【００６５】
また必要に応じて、導電粉等を上記の被覆樹脂中に含有させてもよい。導電粉としては、金属粉、カーボンブラック、酸化チタン、酸化錫、酸化亜鉛等が使用できる。これらの導電粉は、平均粒子径１μｍ以下のものが好ましい。平均粒子径が１μｍよりも大きくなると、電気抵抗の制御が困難になる。
【００６６】
（フルカラー画像現像方法）
また、本発明の画像形成方法では、特に非磁性一成分現像方式において、本発明の電子写真用トナーを使用したフルカラー用トナーを用いて多数回の現像を順次行い、転写媒体上に順次重ねて転写していく非磁性一成分フルカラープロセスを用いることによって、特にハーフトーンの均一再現性に本発明の電子写真用トナーの顕著な効果が得られる。
【００６７】
本発明の画像形成方法を用いるフルカラー非磁性一成分画像形成方法とは、現像ローラ及び該現像ローラ上に供給する現像剤の層厚を均一に規制する現像ブレードを備えた複数の多色現像装置によって、導電性ブラシ帯電器及び露光装置によって感光体上に形成された各色に分割された静電潜像をそれぞれの色に対応する現像剤により順次現像し、転写媒体に転写する方法である。この場合、感光体上の静電潜像の極性と非磁性一成分現像剤の極性とが同一である反転現像方式により現像することが好ましい。また、感光体上の静電潜像と現像ローラを直接接触させて感光体よりも高速で現像ローラを回転させて現像することが好ましい。
【００６８】
図１は、本発明の画像形成方法を適用した一例である画像形成装置の概略構成図である。図１の装置で実施される画像形成方法は、潜像保持体としての感光体である有機感光体ドラムやベルト上に静電潜像を形成する潜像形成工程、該静電潜像を現像剤担持体としての現像ローラ上の現像剤を用いて現像する現像工程、現像されたトナー像を中間転写体上に１次転写し、転写紙上に２次転写する転写工程、転写紙上のトナー像を熱ロールヒートローラやベルト加熱定着する定着工程を有し、本発明の電子写真用トナーを用いた一成分系又は二成分系現像剤を用いて画像を形成する。また、本発明では、上記現像工程において、現像剤担持体上に現像剤の薄層を形成し、潜像保持体と接触または非接触で現像することにより画像を形成する。
【００６９】
さらに本発明の画像形成方法は、図２に示した装置においても適用できる。図２のような現像ローラ及び該現像ローラ上に供給する現像剤の層厚を均一に規制するドクターローラを備えた複数の多色現像装置によって、潜像保持体上に形成された多色に分割された静電潜像をそれぞれの色に対応する現像剤により、それぞれの色に対応した複数の潜像保持体上に現像し、潜像保持表面に転写材を介し転写手段を当接させ該トナー像を該転写材に順次静電転写する。この方法において、本発明の電子写真用トナーを用いた一成分系又は二成分系現像剤を用いて画像を形成する。
【００７０】
【実施例】
以下に実施例及び比較例を挙げて本発明について具体的に説明するが、本発明は、これらの実施例のみに限定されるものではない。また、以下の例において、部及び％は、特に断りのない限り重量基準である。以下では、まず、本発明の電子写真用トナーに用いる樹脂負帯電制御剤の合成例１〜７、並びに、アクリル酸エステル及び／又はメタアクリル酸エステルモノマーを含まない帯電制御剤の合成例８を記載する。次いで、本発明の電子写真用トナーに用いる結着樹脂であるポリエステル樹脂Ａ〜Ｄ及びポリオール樹脂Ａ〜Ｂの合成例について述べる。その後、実施例１として、それらの材料を用いた４色のトナーの製造例、トナー製造例１（トナーＮｏ．Ｔ１）を記載し、そのトナーを用いた画像形成と得られた画像の評価方法及び評価結果について述べる。続く実施例２〜１２及び比較例１〜３では、得られたＮｏ．Ｔ２〜Ｔ１５のトナーをそれぞれ順に使用して画像を作成し、その評価を行った結果を記載する。
【００７１】
（樹脂負帯電制御剤の合成例）
合成例１
３，４−ジクロロフェニルマレイミド３５０部及び２−アクリルアミド−２−メチルプロパンスルホン酸１００部をジメチルホルムアルデヒド（ＤＭＦ）中沸点下、ジターシャリーブチルパーオキサイドを開始剤として８時間共重合した。次いでアクリル酸ｎ−ブチルを５００部、スチレンを５０部加え、ジターシャリーブチルパーオキサイドを開始剤として４時間グラフト重合した後、ＤＭＦを減圧乾燥機により留去し、揮発分１．０重量％、体積抵抗１０．５ｌｏｇΩ・ｃｍ、重量平均分子量１００００、見掛け粘度が１０^４Ｐ（１０^４Ｐ＝１０^４ｇ／ｃｍ・ｓ）となる温度が９６℃の帯電制御樹脂Ａを得た。
【００７２】
合成例２
ｍ−ニトロフェニルマレイミド６００部及びパーフルオロオクタンスルホン酸１００部をジメチルホルムアルデヒド（ＤＭＦ）中沸点下、ジターシャリーブチルパーオキサイドを開始剤として８時間共重合した。次いでアクリル酸２−エチルヘキシルを２５０部、スチレンを３０部加え、ジターシャリーブチルパーオキサイドを開始剤として４時間グラフト重合した後、ＤＭＦを減圧乾燥機により留去し、揮発分３．８重量％、体積抵抗９．５ｌｏｇΩ・ｃｍ、重量平均分子量５５００、見掛け粘度が１０^４Ｐ（１０^４Ｐ＝１０^４ｇ／ｃｍ・ｓ）となる温度が８５℃の帯電制御樹脂Ｂを得た。
【００７３】
合成例３
３，４−ジクロロフェニルマレイミド５００部及び２−アクリルアミド−２−メチルプロパンスルホン酸１５０部をジメチルホルムアルデヒド（ＤＭＦ）中沸点下、ジターシャリーブチルパーオキサイドを開始剤として８時間共重合した。次いでアクリル酸ｎ−ブチルを３５０部、α−メチルスチレンを２５０部加え、ジターシャリーブチルパーオキサイドを開始剤として４時間グラフト重合した後、ＤＭＦを減圧乾燥機により留去し、揮発分０．５重量％、体積抵抗１１．５ｌｏｇΩ・ｃｍ、重量平均分子量９５０００、見掛け粘度が１０^４Ｐ（１０^４Ｐ＝１０^４ｇ／ｃｍ・ｓ）となる温度が１１０℃の帯電制御樹脂Ｃを得た。
【００７４】
合成例４
３，４−ジクロロフェニルマレイミド４００部及びパーフルオロオクタンスルホン酸２００部をジメチルホルムアルデヒド（ＤＭＦ）中沸点下、ジターシャリーブチルパーオキサイドを開始剤として８時間共重合した。次いでアクリル酸ｎ−ブチルを３００部加え、ジターシャリーブチルパーオキサイドを開始剤として４時間グラフト重合した後、ＤＭＦを減圧乾燥機により留去し、揮発分１．７重量％、体積抵抗１０．３ｌｏｇΩ・ｃｍ、重量平均分子量５００００、見掛け粘度が１０^４Ｐ（１０^４Ｐ＝１０^４ｇ／ｃｍ・ｓ）となる温度が１０５℃の帯電制御樹脂Ｄを得た。
【００７５】
合成例５
３，４−ジクロロフェニルマレイミド４００部及び２−アクリルアミド−２−メチルプロパンスルホン酸１００部をジメチルホルムアルデヒド（ＤＭＦ）中沸点下、ジターシャリーブチルパーオキサイドを開始剤として８時間共重合した。次いでアクリル酸ｎ−ブチルを５００部、スチレンを１００部加え、ジターシャリーブチルパーオキサイドを開始剤として４時間グラフト重合した後、ＤＭＦを減圧乾燥機により留去し、揮発分４．８重量％、体積抵抗９．６ｌｏｇΩ・ｃｍ、重量平均分子量３００００、見掛け粘度が１０^４Ｐ（１０^４Ｐ＝１０^４ｇ／ｃｍ・ｓ）となる温度が１０１℃の帯電制御樹脂Ｅを得た。
【００７６】
合成例６
３，４−ジクロロフェニルマレイミド４００部及び２−アクリルアミド−２−メチルプロパンスルホン酸２００部をジメチルホルムアルデヒド（ＤＭＦ）中沸点下、ジターシャリーブチルパーオキサイドを開始剤として８時間共重合した。次いでアクリル酸ｎ−ブチルを２００部、スチレンを４００部加え、溶解した後、ＤＭＦを減圧乾燥機により留去し、揮発分０．６重量％、体積抵抗１１．７ｌｏｇΩ・ｃｍ、重量平均分子量１１５０００、見掛け粘度が１０^４Ｐ（１０^４Ｐ＝１０^４ｇ／ｃｍ・ｓ）となる温度が１１０℃の帯電制御樹脂Ｆを得た。
【００７７】
合成例７
３，４−ジクロロフェニルマレイミド４５０部及びパーフルオロオクタンスルホン酸１５０部をジメチルホルムアルデヒド（ＤＭＦ）中沸点下、ジターシャリーブチルパーオキサイドを開始剤として３時間共重合した。次いでアクリル酸メチルを５００部加え、ジターシャリーブチルパーオキサイドを開始剤として４時間グラフト重合した後、ＤＭＦを減圧乾燥機により留去し、揮発分５．２重量％、体積抵抗９．２ｌｏｇΩ・ｃｍ、重量平均分子量２８００、見掛け粘度が１０^４Ｐ（１０^４Ｐ＝１０^４ｇ／ｃｍ・ｓ）となる温度が８０℃の帯電制御樹脂Ｇを得た。
【００７８】
合成例８
スチレンスルホン酸ナトリウム６０部、ニトロフェニルマレイミド４４０部及びパーフルオロアルキルエチルメタクリレート５００部をジメチルホルムアルデヒド（ＤＭＦ）中沸点下、ジターシャリーブチルパーオキサイドを開始剤として３時間共重合した後、ＤＭＦを減圧乾燥機により留去し、揮発分１．２重量％、体積抵抗１０．２ｌｏｇΩ・ｃｍ、軟化点１３７℃の帯電制御樹脂Ｈを得た。
【００７９】
（ポリエステル樹脂の合成例）
合成例１
攪拌装置、温度計、窒素導入口、流下式コンデンサー、冷却管付き４つ口セパラブルフラスコに、ポリオキシプロピレン（２，２）−２，２−ビス（４−ヒドロキシフェニル）プロパン７４０ｇ、ポリオキシエチレン（２，２）−２，２−ビス（４−ヒドロキシフェニル）プロパン３００ｇ、テレフタル酸ジメチル４６６ｇ、イソドデセニル無水コハク酸８０ｇ、１，２，４−ベンゼントリカルボン酸トリｎ−ブチル１１４ｇをエステル化触媒とともに加えた。窒素雰囲気下で前半２１０℃まで常圧昇温し、後半２１０℃減圧にて撹拌しつつ反応させた。酸価２．３ＫＯＨｍｇ／ｇ、水酸基価２８．０ＫＯＨｍｇ／ｇ、軟化点１０６℃、Ｔｇ６２℃のポリエステル樹脂を得た（以下ポリエステル樹脂Ａという）。
【００８０】
合成例２
ポリオキシプロピレン（２，２）−２，２−ビス（４−ヒドロキシフェニル）プロパン７２５ｇ、ポリオキシエチレン（２，２）−２，２−ビス（４−ヒドロキシフェニル）プロパン１６５ｇ、テレフタル酸５００ｇ、イソドデセニル無水コハク酸１３０ｇ、１，２，４−ベンゼントリカルボン酸トリイソプロピル１７０ｇをエステル化触媒とともにフラスコに加えた。これらを合成例１と同様の装置、同様の処方にて反応させ、酸価０．５ＫＯＨｍｇ／ｇ、水酸基価２５．０ＫＯＨｍｇ／ｇ、軟化点１０９℃、Ｔｇ６３℃のポリエステル樹脂を得た（以下ポリエステル樹脂Ｂという）。
【００８１】
合成例３
ポリオキシプロピレン（２，２）−２，２−ビス（４−ヒドロキシフェニル）プロパン６５０ｇ、ポリオキシエチレン（２，２）−２，２−ビス（４−ヒドロキシフェニル）プロパン６５０ｇ、イソフタル酸５１５ｇ、イソオクテニルコハク酸７０ｇ、１，２，４−ベンゼントリカルボン酸８０ｇをエステル化触媒とともにフラスコに加えた。これらを合成例１と同様の装置、同様の処方にて反応させ、酸価１９．５ＫＯＨｍｇ／ｇ、水酸基価３５．０ＫＯＨｍｇ／ｇ、軟化点１１０℃、Ｔｇ６０℃のポリエステル樹脂を得た（以下ポリエステル樹脂Ｃという）。
【００８２】
合成例４
ポリオキシプロピレン（２，２）−２，２−ビス（４−ヒドロキシフェニル）プロパン７１４ｇ、ポリオキシエチレン（２，２）−２，２−ビス（４−ヒドロキシフェニル）プロパン６６３ｇ、イソフタル酸６４８ｇ、イソオクテニルコハク酸１５０ｇ、１，２，４−ベンゼントリカルボン酸１００ｇをエステル化触媒とともにフラスコに加えた。これらを合成例１と同様の装置、同様の処方にて反応させ、酸価２１．０ＫＯＨｍｇ／ｇ、水酸基価２４．０ＫＯＨｍｇ／ｇ、軟化点１２８℃、Ｔｇ６５℃のポリエステル樹脂を得た（以下ポリエステル樹脂Ｄという）。
【００８３】
（ポリオール樹脂の合成例）
合成例１
攪拌装置、温度計、窒素導入口、冷却管付きセパラブルフラスコに、低分子ビスフェノールＡ型エポキシ樹脂（数平均分子量：約３６０）３７８．４ｇ、高分子ビスフェノールＡ型エポキシ樹脂（数平均分子量：約２７００）８６．０ｇ、ビスフェノールＡ型プロピレンオキサイド付加体のグリシジル化物（前記一般式（１）においてｎ＋ｍ：約２．１）１９１．０ｇ、ビスフェノールＦ２７４．５ｇ、ｐ−クミルフェノール７０．１ｇ、キシレン２００ｇを加えた。窒素雰囲気下で７０〜１００℃まで昇温し、塩化リチウムを０．１８３９ｇ加え，更に１６０℃まで昇温し減圧下でキシレンを留去し、１８０℃の反応温度で７〜９時間重合させて、酸価０．０ＫＯＨｍｇ／ｇ、水酸基価７０．０ＫＯＨｍｇ／ｇ、軟化点１１０℃、Ｔｇ６２℃のポリオール樹脂を得た（以下ポリオール樹脂Ａという）。
【００８４】
合成例２
合成例１の装置を用いて、低分子ビスフェノールＡ型エポキシ樹脂（数平均分子量：約３６０）２０５．３ｇ、高分子ビスフェノールＡ型エポキシ樹脂（数平均分子量：約３０００）５４．０ｇ、ビスフェノールＡ型プロピレンオキサイド付加体のグリシジル化物（前記一般式（１）においてｎ＋ｍ：約２．２）４３２．０ｇ、ビスフェノールＦ２８２．７ｇ、ｐ−クミルフェノール２６．０ｇ、キシレン２００ｇを加えた。窒素雰囲気下で７０〜１００℃まで昇温し、塩化リチウムを０．１８３ｇ加え，更に１６０℃まで昇温し減圧下でキシレンを留去し、１８０℃の反応温度で６〜８時間重合させて、酸価０．０ＫＯＨｍｇ／ｇ、水酸基価５８．０ＫＯＨｍｇ／ｇ、軟化点１０５℃、Ｔｇ５８℃のポリオール樹脂を得た（以下ポリオール樹脂Ｂという）。
【００８５】
実施例１
本実施例では、以下のように電子写真用トナーＴ１を製造し、これを用いて後述するように画像を形成し、その評価を行った。
【００８６】

以上をフラッシャーでよく撹拌する。ここに、ポリエステル樹脂Ａ１２００部を加え、１５０℃で３０分混練後、キシレン１０００部を加えさらに１時間混練、水とキシレンを除去後、圧延冷却しパルペライザーで粉砕、マスターバッチ顔料を得た。
【００８７】
ポリエステル樹脂Ａ １００部
上記マスターバッチ ５部
帯電制御樹脂Ａ ５部
上記材料をヘンシェルミキサーで混合後、２本ロールミルで溶融混練し、混練物を圧延冷却した。その後ジェットミルによる衝突板方式の粉砕機（Ｉ−２式ミル；日本ニューマチック工業社製）と旋回流による風力分級（ＤＳ分級機；日本ニューマチック工業社製）を行い、個数平均径５．２μｍ、体積平均径６．５μｍ（Ｄｖ／Ｄｎ＝１．３）の黒色の着色粒子を得た。その際の単位時間当たりの粉砕処理量は２．３Ｋｇ／Ｈであった。
【００８８】

をフラッシャーでよく撹拌する。ここに、ポリエステル樹脂Ａ１２００部を加え、１５０℃で３０分混練後、キシレン１０００部を加えさらに１時間混練、水とキシレンを除去後、圧延冷却しパルペライザーで粉砕、さらに３本ロールで２回パスし、マスターバッチ顔料を得た。
【００８９】
ポリエステル樹脂Ａ １００部
上記マスターバッチ ５部
帯電制御樹脂Ａ ５部
上記材料をヘンシェルミキサーで混合後、２本ロールミルで溶融混練し、混練物を圧延冷却した。その後、ブラック色の着色粒子製造例と同様に粉砕分級を行い、個数平均径５．４μｍ、体積平均径６．６μｍ（Ｄｖ／Ｄｎ＝１．２）のイエロー色の着色粒子を得た。その際の単位時間当たりの粉砕処理量は２．３Ｋｇ／Ｈであった。
【００９０】

以上をフラッシャーでよく撹拌する。ここに、 ポリエステル樹脂Ａ１２００部を加え、１５０℃で３０分混練後、キシレン１０００部を加えさらに１時間混練、水とキシレンを除去後、圧延冷却しパルペライザーで粉砕、さらに３本ロールミルで２回パスしマスターバッチ顔料を得た。
【００９１】
ポリエステル樹脂Ａ １００部
上記マスターバッチ ５部
帯電制御樹脂Ａ ５部
上記材料をヘンシェルミキサーで混合後、２本ロールミルで溶融混練し、混練物を圧延冷却した。その後、ブラック色の着色粒子製造例と同様に粉砕分級を行い個数平均径５．２μｍ、体積平均径６．８μｍ（Ｄｖ／Ｄｎ＝１．３）マゼンタ色の着色粒子を得た。その際の単位時間当たりの粉砕処理量は２．３Ｋｇ／Ｈであった。
【００９２】

をフラッシャーでよく撹拌する。ここに、ポリエステル樹脂Ａ１２００部を加え、１５０℃で３０分混練後、キシレン１０００部を加えさらに１時間混練、水とキシレンを除去後、圧延冷却しパルペライザーで粉砕、さらに３本ロールミルで２回パスしマスターバッチ顔料を得た。
【００９３】
ポリエステル樹脂Ａ １００部
上記マスターバッチ ３部
帯電制御樹脂Ａ ５部
上記材料をヘンシェルミキサーで混合後、２本ロールミルで溶融混練し、混練物を圧延冷却した。その後、ブラック色の着色粒子製造例と同様に粉砕分級を行い、個数平均径５．９μｍ、体積平均径６．９μｍ（Ｄｖ／Ｄｎ＝１．２）のシアン色の着色粒子を得た。その際の単位時間当たりの粉砕処理量は２．３Ｋｇ／Ｈであった。
【００９４】
５）外添剤との混合
得られた４色の着色粒子１００重量部それぞれに、外添剤として疎水性シリカ（ワッカー社ＨＤＫ Ｈ２０００）１．０重量部、疎水性シリカ（日本アエロジル社 アエロジル ＲＸ−５０）１．０重量部、疎水性酸化チタン（テイカ社 ＭＴ−１５０ＡＩ）０．５重量部を加え、ヘンシェルミキサーにより混合し、目開き１００μｍのメッシュを通過させる事により粗大粒子や凝集物を取り除くことにより４色の電子写真用トナーＴ１を得た。
【００９５】
上記のように製造したトナーを二成分系現像剤に用いて画像評価する場合は、シリコーン樹脂により０．３μｍの平均厚さでコーティングされた平均粒径５０μｍのフェライトキャリアを用い、キャリア１００重量部に対し各色トナー５重量部を容器が転動して攪拌される型式のターブラーミキサーを用いて均一混合し帯電させて、現像剤を作製した。
【００９６】
（トナー評価機）
得られたトナーは４色の現像部が非磁性一成分系現像剤を１つのベルト感光体に各色順次現像し、中間転写体に順次転写し、紙等に４色を一括転写する方式のフルカラーレーザープリンター イプシオ ５０００（リコー社製、評価機Ａとする）、４色用の非磁性一成分系の現像部と４色用の感光体を有し、転写紙等に順次転写するタンデム方式のフルカラーＬＥＤプリンター ＧＬ８３００（富士通社製、評価機Ｂとする）と二成分系現像剤を有する４色の現像部によって１つのドラム状感光体に各色現像し、中間転写体に順次転写し、転写紙等に４色のトナーを一括転写する方式のフルカラーレーザー複写機 イマジオカラー ２８００（リコー社製、評価機Ｃとする）と、フルカラーレーザープリンター イプシオカラー ８０００（リコー社製、評価機Ｄとする）により評価した。評価機ＡとＢの現像部は弾性体からなる現像ローラーと層厚規制のステンレスブレードからなる非磁性一成分現像ユニットを搭載している。また、４種のすべての評価機は感光体上の静電潜像の極性と非磁性一成分現像剤の極性とが同一である反転現像方式である。実施例又は比較例と用いた評価機の組み合わせは、後述する表２-１〜表２-３に示した。
【００９７】
（評価項目）
いずれの項目も５％画像面積の画像チャートを１０００００枚まで連続でランニングした後、以下に述べる評価を行った。評価結果は、後述する実施例２〜１２及び比較例１〜３の結果と併せて表２に示した。
【００９８】
１）画像濃度
ベタ画像出力後、画像濃度をＸ−Ｒｉｔｅ（Ｘ−Ｒｉｔｅ社製）により測定した。これを各色単独に５点測定し各色ごとに平均を求めた。
【００９９】
２）地肌汚れ
白紙画像を現像中に停止させ、現像後の感光体上の現像剤をテープ転写し、未転写のテープの画像濃度との差を９３８スペクトロデンシトメーター（Ｘ−Ｒｉｔｅ社製）により測定した。
【０１００】
３）フィルミング
現像ローラ又は感光体上のトナーフィルミング発生状況の有無を観察した。○がフィルミングがなく、△はスジ上のフィルミングが見られ、×は全体的にフィルミングがあるとした。
【０１０１】
４）スジ
現像ローラ上のトナー薄層及び画像上の色スジ発生状況の有無を観察した。○が色スジが殆どなく、△は数本程度のスジが見られ、×は全体的に色スジがあるとした。
【０１０２】
５）物性測定
５−１）〔粒径〕
トナーの粒径は、コールターエレクトロニクス社製の粒度測定器「コールターカウンターＴＡＩＩ」を用い、アパーチャー径１００μｍで測定した。体積平均粒径及び個数平均粒径は上記粒度測定器により求めた。
【０１０３】
５−２）〔帯電量〕
二成分現像剤の場合；現像剤６ｇを計量し、密閉できる金属円柱に仕込みブローして帯電量を求めた。トナー濃度は４．５〜５．５重量％に調整した。
一成分トナーの場合；現像ローラ（スリーブ）上にトナーを搬送させ、各環境下での吸引トリボ測定法にて測定した。なお、高温高湿とは３２℃８０ＲＨ％で、低温低湿１０℃３０ＲＨ％であった。
【０１０４】
５−３）樹脂負帯電制御剤の分散粒子径
トナーを超薄切片化し、酸化ルテニウムにより染色した後、日立製作所社製透過型電子顕微鏡Ｈ−８００で５０００〜２００００倍に拡大した写真画像を用い、分散状態を観察した。
【０１０５】
６）透明性
９０ｍｍ／ｓの定着速度で１６０℃にて、ＯＨＰシートでサンプルを作成した。これをヘイズ度メーター（スガ試験機械社）を用いて、透明性を測定した。ヘイズ度が１５％以下のものを○、３０％未満のものを△、３０％以上を×と評価した。
【０１０６】
７）樹脂負帯電制御剤の揮発分
２０メッシュパスに粉砕したサンプル１．５〜２．０ｇを精秤し、１５０℃の循風乾燥機（タバイ製）に４５分間静置した後取り出し、乾燥残渣を精秤し下記計算式により求めた。
揮発分（％）＝（１−乾燥残渣重量／サンプル重量）×１００
【０１０７】
８）樹脂負帯電制御剤の体積抵抗
例えば、篩等を使用して整粒した樹脂粉末３ｇを約５００Ｋｇｆ／ｃｍ^２加圧し、面積１２．５ｃｍ^２、厚さ１．８〜２．２ｍｍ程度のペレット状に成形したものを市販の誘電体損測定機（安藤電気社製、ＴＲ−１０Ｃ型）を用いて、周波数１ＫＨｚを印加した状態で測定を行い、これから体積抵抗を算出した。
【０１０８】
９）生産性
上述にしたように、混練物をジェットミルによる衝突板方式の粉砕機（Ｉ−２式ミル；日本ニューマチック工業社製）と旋回流による風力分級（ＤＳ分級機；日本ニューマチック工業社製）を行い、体積平均径６．５μｍ（Ｄｖ／Ｄｎ＝１．５以下）の着色粒子を得るよう調整し、その際の単位時間当たりの粉砕処理量（Ｋｇ／Ｈ）を測定した。２．０（Ｋｇ／Ｈ）以上かつ原材料の凝集や配管への付着がないものを○、２．０（Ｋｇ／Ｈ）未満又は原材料の凝集が発生したり、配管への固着が発生した場合は×とした。
【０１０９】
実施例２〜１２
後述する表１に示すように、トナー粒径、帯電制御樹脂及びその添加量、並びに、結着樹脂を選択し、それ以外は実施例１と同様にして４色のトナーをそれぞれ製造し、トナーＮｏ．Ｔ２〜Ｔ１２とした。その後、各トナーを用いて画像を形成し、実施例１と同様の評価を行った。その結果を後述する表２-１〜表２-３に示す。
【０１１０】
比較例１
比較例１では、樹脂負帯電制御剤としてサリチル酸誘導体亜鉛塩を表１に示した添加量用いた以外は、実施例１と同様にしてトナー（トナーＮｏ．Ｔ１３）を製造した。サリチル酸誘導体亜鉛塩はオリエント社製 ボントロンＥ−８４を用いた。このトナーを用いて画像を形成し、実施例１と同様に評価を行った。その結果を以下の表２-１〜表２-３に示す。
【０１１１】
比較例２
比較例２では、結着樹脂としてスチレン・アクリル樹脂を用いた以外は、実施例１と同様にしてトナー（トナーＮｏ．Ｔ１４）を製造した。スチレン・アクリル樹脂はｓｔ−−／ｎ−ＢＭＡ、Ｍｎ５０００、Ｍｗ１２０００、Ｔｇ６１℃のものを用いた。このトナーを用いて画像を形成し、実施例１と同様に評価を行った。その結果を以下の表２-１〜表２-３に示す。
【０１１２】
比較例３
比較例３では、アクリル酸エステル及び／又はメタアクリル酸エステルモノマーを含まない帯電制御剤樹脂Ｈを表２に示した添加量用いた以外は、実施例１と同様にしてトナー（トナーＮｏ．Ｔ１５）を製造した。このトナーを用いて画像を形成し、実施例１と同様に評価を行った。その結果を以下の表２-１〜表２-３に示す。
【０１１３】
【表１】

【０１１４】
【表２】

【０１１５】
【表３】

【０１１６】
【表４】

【０１１７】
【発明の効果】
本発明によれば、二成分及び一成分カラー現像方式のいずれの方式においても、従来より長期の連続プリント後、感光体、現像剤層厚規制部材や現像スリーブへのフィルミングがなく、トナーの帯電及び搬送を安定化し、初期画像と同等の画像濃度、高品位な出力画像を維持できる電子写真用トナーが得られる。また、連続使用における帯電の低下が少ないため、画像濃度の変動、低現像性、地汚れ、現像器内のトナー飛散等の問題がなく、発色性、色再現性のよい画像が得られる。このように長期の耐久性があるため、現像ユニット、感光体ユニット等の長寿命化が達成でき、使用後発生するリサイクル物、廃棄物が従来より少なく、ユーザーのそれらの作像ユニット交換の手間を少なくすることが可能になる。さらにまた、トナーを混練、粉砕・分級する生産工程において、生産性の良好な電子写真用トナーが得られる。
【図面の簡単な説明】
【図１】 本発明の画像形成方法を適用した画像形成装置の一例の部分概略構成図である。
【図２】 本発明の画像形成方法を適用した多色現像装置の一例の部分概略構成図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner used as a developer for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like, and an electrophotographic developing apparatus using the toner. More specifically, the present invention relates to an electrophotographic toner, an electrophotographic developer, an image forming apparatus, and an image forming method used in a copying machine, a laser printer, and a plain paper fax machine using a direct or indirect electrophotographic developing system. Further, full-color copiers, full-color laser printers using direct or indirect electrophotographic multicolor image development systems, electrophotographic toners, electrophotographic developers, image forming apparatuses, and image forming methods used in full-color plain paper fax machines, etc. About.
[0002]
[Prior art]
In the developing process, the developer used in electrophotography, electrostatic recording, electrostatic printing, etc. is once attached to an image carrier such as a photoreceptor on which an electrostatic charge image is formed, and then After being transferred from the photoreceptor to a transfer medium such as transfer paper in the transfer process, it is fixed on the paper surface in the fixing process. At that time, as a developer for developing the electrostatic image formed on the latent image holding surface of the image carrier, a two-component developer composed of a carrier and a toner, and a one-component developer that does not require a carrier. (Magnetic toner, non-magnetic toner) are known. In the two-component development method, the developer deteriorates due to the toner particles adhering to the carrier surface, and only the toner is consumed, so that the toner concentration in the developer gradually decreases. For this reason, the mixing ratio with the carrier must be maintained at a constant ratio, and there is a disadvantage that the developing device is enlarged. On the other hand, the one-component development method has the above-mentioned disadvantages and has advantages such as miniaturization of the apparatus, and is therefore becoming the mainstream of the development method.
[0003]
Electrophotographic processes using a one-component developer are classified into a magnetic one-component development method using magnetic toner and a non-magnetic one-component development method using non-magnetic toner. The magnetic one-component development system uses a developer carrying member provided with a magnetic field generating means such as a magnet inside, holds magnetic toner containing a magnetic material such as magnetite, and develops the layer with a layer thickness regulating member. In recent years, many have been put to practical use in small printers and the like. On the other hand, in the non-magnetic one-component development method, since the toner does not have magnetism, the toner replenishing roller or the like is pressed against the developer carrying member, and the toner is supplied onto the developer carrying member to be held electrostatically. The layer thickness is regulated by a layer thickness regulating member. Therefore, since it does not contain a colored magnetic material, it has the advantage of being compatible with colorization, and since a magnet is not used for the developer carrier, it is possible to reduce the weight and cost. It is beginning to become.
[0004]
On the other hand, in the two-component development system, a carrier is used as a means for charging and transporting toner, and the toner and the carrier are sufficiently agitated and mixed in the developing device and then transported to the developer carrying member for development. Even in use, it is possible to maintain stable charging and conveyance, and it is easy to cope with a high-speed developing device.
[0005]
However, in the current situation, there are still many problems to be improved in the one-component development method. In the one-component development method, since there is no stable charging / conveying means like a carrier, charging and conveyance defects are likely to occur due to long-term use and high speed. That is, in the one-component development method, after the toner is conveyed onto the developer carrier, the toner is thinned by the layer thickness regulating member and developed, but the friction between the toner and the developer carrier, the layer thickness regulating member, etc. Since the contact / friction charging time with the charging member is very short, the amount of low-charged or reverse-charged toner tends to increase more than the two-component developing method using a carrier. Particularly in the non-magnetic one-component developing method, the toner (developer) is usually transported by at least one toner transport member, and the electrostatic latent image formed on the latent image carrier is developed by the transported toner. In this case, the toner layer thickness on the surface of the toner conveying member must be made as thin as possible. This is true even when a two-component developer having a very small carrier is used, and a one-component developer is used, and a toner having a high electric resistance is used. Sometimes this toner needs to be charged by a developing device, so the toner layer thickness must be significantly reduced. This is because if the toner layer is thick, only the surface of the toner layer is charged, and the entire toner layer is difficult to be uniformly charged. For this reason, the toner is required to maintain a quicker charging speed and an appropriate charge amount.
[0006]
In recent years, office automation and colorization have further progressed in offices. In addition to copying originals consisting of only conventional characters, originals including graphs, etc., created with a personal computer, can be output with a printer and used for presentations. As a result, the opportunity to copy many sheets is increasing. Printer output images are mostly solid images, line images, and halftone images. Accordingly, market demands for image quality are changing, and demands for high reliability and the like are further increasing.
[0007]
Conventionally, a charge control agent has been added to stabilize the charging of the toner. The charge control agent functions to control the triboelectric charge amount of the toner and maintain the triboelectric charge amount. Among the charge control agents, representative examples of negative charge include monoazo dyes, salicylic acid, naphthoic acid, metal salts / metal complexes of dicarboxylic acids, diazo compounds, complex compounds of boron, and the like. Typical charge control agents having a positive charge include quaternary ammonium salt compounds, imidazole compounds, nigrosine, azine dyes and the like. However, since these charge control agents are colored, there is a problem that the hue changes when used for color toners. In addition, since such a charge control agent is poorly dispersible in the binder resin, what is present on the surface of the toner, which is greatly involved in charging, is likely to be detached. There is a drawback of being easily contaminated, such as body filming.
[0008]
For this reason, in the past, a good image was obtained in the initial stage, but the image quality gradually changed, resulting in the phenomenon of background stains and blurring. Especially when it is applied to color copying and used continuously while replenishing toner, the charge amount of the toner will decrease, resulting in an image that is significantly different from the color tone of the initial copied image, and it can not withstand long-term use and thousands The image forming unit called a process cartridge had to be replaced at an early stage with about one sheet. For this reason, the load on the environment is large, and it takes time and effort for the user. Furthermore, since many of these charge control agents contain heavy metals such as chromium, they have recently become a problem from the viewpoint of safety.
[0009]
Therefore, in order to improve the above problems, JP-A-63-88564, JP-A-63-184762, JP-A-3-56974, JP-A-6-230609 disclose dispersibility in a binder resin, toner A resin charge control agent having improved transparency and safety of a fixed image is disclosed. Since these resin charge control agents have good dispersibility with the binder resin, they are excellent in stable chargeability and transparency. However, these resin charge control agents have a disadvantage that the charge amount and the charge speed are inferior to those using the above-mentioned monoazo dye, salicylic acid, naphthoic acid, and metal salt / metal complex salt of dicarboxylic acid. In addition, the chargeability is improved by increasing the amount of the resin charge control agent added, but the toner fixability (low temperature fixability, offset resistance) is adversely affected. Furthermore, these compounds have high environmental stability (humidity resistance) of the charge amount. For this reason, there is a problem that soiling (fogging) is likely to occur.
[0010]
In JP-A-8-30017, JP-A-9-171271, JP-A-9-212896, and JP-A-11-218965, a monomer containing an organic acid salt such as a sulfonate group and an aromatic group having an electron-withdrawing group. Copolymers with monomers have been proposed. However, sufficient charge amount is ensured by the hygroscopicity and adhesiveness that are thought to be caused by the monomer containing organic acid salt such as sulfonate group, but the dispersion to the binder resin is not sufficient, and the toner is used for a long time. The effect of suppressing the variation in charging and preventing the developing sleeve and the photoconductor filming is not sufficient. Further, the volatile content of the binder resin for toner obtained by a known polymerization method such as solution polymerization or bulk polymerization is usually 0.5 to 2.0% by weight by the devolatilization step. More water and polymerization solvent are assumed to be attributed to the monomer containing the organic acid salt such as sulfonate group, and the volatile content increases. For this reason, there are problems in storage stability of the charge control agent itself, and there are problems in handling such as aggregation when the material is allowed to stand after pre-mixing of the material before kneading, and powder transport cannot be performed. Further, the dispersion into the binder resin is not sufficient, and the effect of suppressing the variation in charging of the toner for a long time and preventing the developing sleeve and the photosensitive member filming are not sufficient. Furthermore, in terms of manufacturability in the toner pulverization method, monoazo dyes, salicylic acid, naphthoic acid, dicarboxylic acid metal salts and metal complex salts are used as charge control agents, such as fixing to each part in the pulverizer and reducing the amount of pulverization per unit time. There was also an adverse effect of lower productivity than when it was used.
[0011]
Further, in order to further improve dispersibility in the styrene resin or polyester resin as a binder resin, a monomer containing an organic acid salt such as a sulfonate group, an aromatic monomer having an electron withdrawing group, and a binder resin are used. A charge control agent consisting of a copolymer with a styrene monomer when the styrene resin is used, and a polyester monomer when the binder resin is a polyester resin has also been proposed. The effect of preventing sleeve and photoreceptor filming is not sufficient. In particular, as a binder resin for a full color toner, a polyester resin and a polyol resin which are suitable in terms of color developability and image strength are insufficient.
[0012]
Furthermore, in recent years, the demand for printers has expanded, and the size, speed, and cost of the apparatus have been increased, and the apparatus is required to have higher reliability and longer life. Therefore, the toner is required to maintain various characteristics for a long time. However, these resin charge control agents cannot maintain the charge control effect and contaminate the developing sleeve and the layer thickness regulating member (blade or roller). However, there are problems that the charging performance of the toner is deteriorated and the photosensitive member is filmed.
[0013]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION In view of the above circumstances, the present invention aims to solve the problems without impairing the advantages of a resin charge control agent that is excellent in dispersibility in a binder resin, transparency of a toner-fixed image, and safety. It was made as. That is, an object of the present invention is to provide an electrophotographic toner, a developer and an image forming device that can stabilize the charge amount and transport amount of the toner even when used for a long period of time, and can provide high image quality with high image density and low background stain. Is to provide a method. In particular, in a one-component development system in which development is performed by forming a thin layer of toner on a toner conveying member (developing sleeve) with a layer thickness regulating member, there is no change in toner chargeability after continuous printing, and it is equivalent to the initial image. An object of the present invention is to provide an electrophotographic toner, a developer, an image forming apparatus, and an image forming method capable of obtaining tens of thousands or more of image quality.
[0014]
Another object of the present invention is to provide electrophotographic toner, developer, and image that prevent contamination of the developing sleeve and the layer thickness regulating member (blade and roller) and filming of the photoconductor more than tens of thousands of sheets in long-term use. A forming apparatus and an image forming method are provided.
[0015]
Still another object of the present invention is to provide an electrophotographic toner, a developer, an image forming apparatus, and an image forming method that cause less toner scattering in a developing machine even in long-term use.
[0016]
Another object of the present invention is to provide an electrophotographic toner, a developer, an image forming apparatus, and an electrophotographic toner that reduce the burden on the environment and reduce the user's time and effort by allowing the developing unit and the photosensitive unit to be used for a long period of time. An image forming method is provided.
[0017]
Another object of the present invention is to provide an electrophotographic toner, a developer, an image forming apparatus, and an image forming method that have good color reproducibility by using a colorless or light-colored resin charge control agent.
[0018]
Furthermore, another object of the present invention is a method obtained from a production process in which toner is kneaded, pulverized and classified, so that there is no sticking in the pulverization process, and there is no excessive pulverization and high pulverization throughput per unit time. It is an object of the present invention to provide an electrophotographic toner having a high quality.
[0019]
[Means for Solving the Problems]
In order to solve such a problem, the inventors of the present invention focused on the constituent components of the resin charge control agent and have made extensive studies. As a result, it has been found that it is effective to use a resin negative charge control agent having a specific component for a polyester resin or a polyol resin that is suitable as a binder resin for a full color toner in terms of color developability and image strength. It was. When the resin negative charge control agent is used, high toner charge amount and sharp charge distribution can be obtained, preventing contamination of developing sleeves and layer thickness regulating members and photoconductor filming over a long period of tens of thousands of sheets. Further, the inventors have found that an electrophotographic toner, a developer, and an image forming method with good grindability and high productivity can be obtained.
[0020]
  That is, the present invention relates to an electrophotographic toner containing at least a binder resin, a colorant and a negative charge control agent, wherein the binder resin is a polyester and / or a polyol, and the negative charge control agent isApparent viscosity by flow tester is 10 ⁴ P (10 ⁴ P = 10 ⁴ g / cm · s) is 85 to 110 ° C., and the volume resistance is 9.5 to 11.5 log Ω · cm,It is a resin negative charge control agent comprising (1) a sulfonic acid-containing monomer, (2) an aromatic monomer having an electron withdrawing group, and (3) an acrylate monomer and / or a methacrylic acid ester monomer. Electrophotography characterized byforProvide toner.
[0021]
Hereinafter, the present invention will be described in detail.
Examples of the sulfonic acid-containing monomer constituting the resin negative charge control agent of the present invention include aliphatic sulfonic acid-containing monomers and aromatic sulfonic acid-containing monomers. Examples of the aliphatic sulfonic acid-containing monomer include alkali metal salts such as vinyl sulfonic acid, allyl vinyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, perfluorooctane sulfonic acid, methacryloyloxyethyl sulfonic acid, and alkaline earth. Metal salts, amine salts, quaternary ammonium salts and the like. Examples of the aromatic sulfonic acid-containing monomer include alkali metal salts such as styrene sulfonic acid, sulfophenyl acrylamide, sulfophenyl maleimide, and sulfophenyl itaconimide, alkaline earth metal salts, amine salts, and quaternary ammonium salts. A salt of heavy metal (nickel, copper, zinc, mercury, chromium, etc.) is not preferable from the viewpoint of safety.
[0022]
Examples of aromatic monomers having an electron-withdrawing group include styrene-substituted products such as chlorostyrene, dichlorostyrene, bromostyrene, fluorostyrene, nitrostyrene, and cyanstyrene, chlorophenyl (meth) acrylate, bromophenyl (meth) acrylate, and nitro. Phenyl (meth) acrylate substitution products such as phenyl (meth) acrylate and chlorophenyloxyethyl (meth) acrylate, and phenyl (meth) acrylamide substitution such as chlorophenyl (meth) acrylamide, bromophenyl (meth) acrylamide, and nitrophenyl (meth) acrylamide Chlorophenylmaleimide, dichlorophenylmaleimide, nitrophenylmaleimide, nitrochlorophenylmaleimide, etc. Ruitakon'imido, dichlorophenyl itaconic imides, nitrophenyl itaconic imide, phenyl itaconic imide substituents such as nitro-chlorophenyl itaconate imide, chlorophenyl vinyl ether, phenyl vinyl ether substituents such as nitro phenyl vinyl ether. In particular, a phenylmaleimide-substituted product and a phenylitaconimide-substituted product substituted with a chlorine atom or a nitro group are preferred in terms of chargeability and filming resistance.
[0023]
Examples of acrylic ester and / or methacrylic ester monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, and (meth) acrylic. Examples include isobutyl acid, stearyl (meth) acrylate, dodecyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. Of these, n-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable.
[0024]
Adding a sulfonic acid-containing monomer to the structure of the resin negative charge control agent improves the negative charge imparting effect of the resin negative charge control agent, but reduces the environmental stability (temperature and humidity stability) of the toner due to hygroscopicity. Therefore, it is generally known to use it as a copolymer with an aromatic monomer or the like having an electron withdrawing group. However, when this charge control agent is used for toner, it is sufficient that the electrophotographic image to be produced is about several thousand sheets. However, if it is used for a long period of several tens of thousands of sheets, contamination of the developing sleeve and the layer thickness regulating member may occur. There is a problem that the filming of the photoconductor occurs, the charging stability of the toner and the high image quality are not sufficiently maintained, and the productivity is lowered. In order to compensate for these disadvantages, polyester resins and polyol resins that are suitable in terms of color developability and image strength are used as binder resins for full-color toners. In contrast, (1) sulfonic acid-containing monomers and (2) electron suction A copolymer containing an aromatic monomer having a group and (3) an acrylic ester and / or methacrylic ester monomer is used as a resin negative charge control agent. As a result, it has excellent chargeability and environmental stability over a long period of time, is easy to form a thin layer without contamination of the developing sleeve and layer thickness regulating member, can prevent photoconductor filming, maintains high image quality, and is productive. A high electrophotographic toner can be obtained.
[0025]
These effects are presumed to be as follows. That is, the negative charge imparting effect is enhanced by using a sulfonic acid-containing monomer and an aromatic monomer having an electron withdrawing group in combination. By using an acrylic ester and / or methacrylic ester monomer for this, the environmental stability of charging is further enhanced, the resin hardness is increased, and the grindability is improved. At the same time, there is no contamination of the developing sleeve and the layer thickness regulating member, and the effect of preventing photoconductor filming is improved. In addition, by combining with a polyester resin or polyol resin suitable for color development and image strength as a binder resin for full-color toner, an appropriate dispersibility of toner particles can be obtained, and an electrophotographic toner with a sharp charge distribution can be obtained. As a result, long-term charging stability and high image quality can be obtained when toner is used.
[0026]
The composition ratio of the monomer in the resin charge control agent used in the electrophotographic toner of the present invention is preferably 1 to 30% by weight, more preferably 2 to 20% by weight of the sulfonic acid-containing monomer with respect to the resin negative charge control agent. is there. When the sulfonic acid-containing monomer is less than 1% by weight based on the resin negative charge control agent, the rise of charge and the charge amount are not sufficient, and the image is likely to be affected. If it exceeds 30% by weight, the environmental stability of charging deteriorates, the charge amount at high temperature and high humidity is low, the charge amount at low temperature and low humidity becomes high, and the charge stability of the toner and the maintenance of high image quality are not sufficient. Furthermore, contamination of the developing sleeve and the layer thickness regulating member and photoconductor filming are likely to occur, and there is a problem that productivity at the time of toner production by the kneading / pulverization method is also lowered. The aromatic monomer having an electron withdrawing group is preferably 1 to 80% by weight, more preferably 20 to 70% by weight, based on the resin negative charge control agent. If it is less than 1% by weight, the charge amount is not sufficient, and background stains and toner scattering are likely to occur. On the other hand, if it exceeds 80% by weight, the dispersion in the toner is poor, the charge distribution of the toner is widened, the background stains and the toner scattering are likely to occur, and the high image quality cannot be sufficiently maintained. Moreover, 10-80 weight% is preferable with respect to a resin negative charge control agent, and, as for an acrylic ester and / or a methacrylic acid ester monomer, More preferably, it is 20-70 weight%. If it is less than 10% by weight, sufficient charging environmental stability cannot be obtained, and the pulverization property at the time of toner production by the kneading / pulverization method is not sufficient, contamination of the developing sleeve and the layer thickness regulating member, Photoconductor filming cannot be sufficiently prevented. On the other hand, if it exceeds 80% by weight, the rise of charge and the charge amount are not sufficient, and the image tends to be affected.
[0027]
The resin negative charge control agent used in the electrophotographic toner of the present invention may further contain an aromatic vinyl monomer. Examples of the aromatic vinyl monomer include styrene, vinyl toluene, α-methyl styrene, and the like. The aromatic vinyl monomer is preferably 30% by weight or less, more preferably 3 to 20% by weight, based on the resin negative charge control agent. When the amount of the aromatic vinyl monomer exceeds 30% by weight, the resin becomes hard, the dispersibility in the toner is lowered, the charge distribution is widened, and the soiling and toner scattering in the machine are likely to occur. Further, the toner fixability, particularly the color developability when color toners are mixed, becomes poor.
[0028]
The dispersed particle diameter of these resin negative charge control agents is preferably 0.05 to 1.50 μm for the major axis and 0.02 to 1.00 μm for the minor axis when observed with a transmission electron microscope. When the major axis exceeds 1.50 μm and the minor axis exceeds 1.00 μm, the toner charge distribution is widened, and background contamination and toner scattering are likely to occur. When the major axis is 0.05 μm and the minor axis is less than 0.02 μm, the rising of the charge and the charge amount are not sufficient, and the image tends to be affected. The weight average diameter of the toner at this time is 6.0 to 8.0 μm.
[0029]
In order to form the dispersion particle size of the resin negative charge control agent within this range, for example, a mixture of a developer component including a binder resin, a main charge control agent and a pigment, and a by-product is charged into a kneader and melted. When kneading, a uniaxial or biaxial continuous kneader or a batch kneader using a roll mill may be used as the melt kneader. When using a twin-screw extruder, it is important to carry out under appropriate conditions that do not cause the molecular chain of the binder resin to be broken. Specifically, the melt-kneading temperature refers to the softening point of the binder resin. Should be performed, if the temperature is lower than the softening point, the cutting is severe, and if the temperature is too high, the dispersion does not proceed. In particular, in order to set the resin negative charge control agent used in the present invention to a desired dispersed particle size in the binder resin, the powder particle size of each resin material in the powder state is prepared, and the outflow start temperature is adjusted from the softening temperature. The kneading temperature and the shaft rotation speed of the twin-screw extruder and the feed amount of the mixture may be appropriately controlled.
[0030]
The resin negative charge control agent used for the electrophotographic toner of the present invention has an apparent viscosity of 10 by a flow tester.⁴P (10⁴P = 10⁴g / cm · s) is preferably 85 to 110 ° C. When the temperature is less than 85 ° C., appropriate dispersibility in the toner cannot be obtained, and not only charging is lowered, but also storage stability is poor and solidification (aggregation) is likely to occur. In the method obtained from the production process of kneading, pulverization and classification, sticking in the pulverization process is likely to occur, and the productivity is deteriorated. On the other hand, when the temperature exceeds 110 ° C., dispersibility in the toner is lowered, the charge distribution is widened, and background contamination and toner scattering are likely to occur. Further, the toner fixability, particularly the color developability when color toners are mixed, becomes poor. Apparent viscosity is 10⁴P (10⁴P = 10⁴g / cm · s) The temperature is 10 kg / cm using a flow tester.², Measuring the viscosity at an orifice of 1 mm × 1 mm and a heating rate of 5 ° C./min, an apparent viscosity of 10⁴P (10⁴P = 10⁴g / cm · s). Shimadzu Corporation CFT-500 type can be used as a flow tester.
[0031]
The resin negative charge control agent used in the toner of the present invention preferably has a volatile content of 5% by weight or less. When the volatile content exceeds 5% by weight, the resin negative charge control agent may have a storage stability of the resin negative charge control agent itself due to moisture or polymerization solvent residues that may be caused by a monomer containing an organic acid such as sulfonic acid. Problems arise and handling problems occur, such as aggregation when the material is allowed to stand after pre-mixing before kneading, and the powder cannot be transported. Further, the dispersion into the binder resin is not sufficient, and the effect of suppressing variation in charging of the toner for a long time and preventing the developing sleeve and the photosensitive member filming are not sufficient. In the toner pulverization process, monoazo dyes, salicylic acid naphthoic acid, metal salts of dicarboxylic acids, and metal complex salts are used as charge control agents, such as toner fixing to each part in the pulverizer and a small amount of pulverization per unit time. There is also an adverse effect of lower productivity than when it was.
[0032]
Further, the volume resistance value of the resin negative charge control agent used in the toner of the present invention is preferably 9.5 to 11.5 log Ω · cm, more preferably 10.0 to 11.0 log Ω · cm. The amount of charge of the toner is affected by the variation in volume resistance, which may be caused by residues of the catalyst, polymerization inhibitor, solvent, etc. during the synthesis of the aromatic monomer having an electron withdrawing group contained in the resin negative charge control agent. This is because a desired charge amount may not be obtained. Therefore, problems such as rising of charge of the toner containing the resin negative charge control agent and charge up of the saturation charge amount may occur. When the volume resistance of the resin negative charge control agent is less than 9.5 log Ω · cm, the toner on the developing roller cannot initially obtain a sufficient charge amount, and soiling and toner scattering occur. When the volume resistance of the resin negative charge control agent exceeds 11.5 log Ω · cm, the toner on the developing roller can initially obtain the desired charge amount, but it is charged up over time, and development is possible with the one-component development method. The toner thin layer on the roller is not uniform, color streaks and unevenness occur on the image, and in the two-component development method, the image density is lowered, and background staining and toner scattering occur.
[0033]
Moreover, it is preferable that the weight average molecular weights of the resin charge control agent of this invention are 5000-100000. If it is less than 5,000, proper dispersibility in the toner will not be obtained, and not only will the charge be reduced, but also when the toner is kneaded, pulverized and classified, it will be stuck in the pulverizing step. Easy to degrade productivity. On the other hand, if it exceeds 100,000, the dispersibility in the toner is lowered, the charge distribution is widened, the background stains and the toner scattering in the machine are liable to occur, and the toner fixing property and color developing property become poor.
[0034]
The resin charge control agent is usually attached to the surface of the toner base particles (base toner particles) or dispersed in the base particles. The resin negative charge in the electrophotographic toner of the present invention is used. The addition amount of the control agent is preferably 0.1 to 20% by weight, and more preferably 0.5 to 10% by weight with respect to the base toner particles. If it is less than 0.1% by weight, the rising of the charge and the charge amount are not sufficient, and the image tends to be affected. When it exceeds 20% by weight, the dispersion becomes poor, the charge distribution becomes wide, and the background stains and the toner scattering in the machine tend to occur. In addition to the resin negative charge control agent defined in the present invention, as the charge control agent, at least one selected from the group consisting of a chromium complex or salt of salicylic acid and a chromium complex or salt of an alkyl salicylic acid may be used in combination. Good.
[0035]
As the binder resin used in the electrophotographic toner of the present invention, a polyester resin and / or a polyol resin suitable as a binder resin for a full-color toner from the viewpoint of color developability and image strength are used. In a color image, several types of toner layers are stacked several times, so that the toner layer becomes thick, and cracks and defects of the image due to insufficient strength of the toner layer occur, or an appropriate gloss is lost. For this reason, a polyester resin or a polyol resin is used to maintain an appropriate gloss and excellent strength.
[0036]
The polyester resin can be generally obtained by an esterification reaction of a polyhydric alcohol and a polycarboxylic acid. Among the monomers constituting the polyester resin in the present invention, examples of the alcohol monomer include trifunctional or higher polyfunctional monomers such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3- Diols such as propylene glycol, 1,4-butadieneol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, bisphenol A, hydrogenated bisphenol A, polyoxypropylene Bisphenol A alkylene oxide adducts such as bisphenol A, other dihydric alcohols, or sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol , Tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylol Mention may be made of ethane, trimethylolpropane, 1,3,5-trihydroxybenzene and other trihydric or higher polyhydric alcohols.
[0037]
Of the monomers constituting the polyester resin, those using a bisphenol A alkylene oxide adduct as a main component monomer are preferably used. When a bisphenol A alkylene oxide adduct is used as a constituent monomer, a polyester having a relatively high glass transition point is obtained due to the nature of the bisphenol A skeleton, and the copy blocking resistance and heat resistant storage stability are good. In addition, the presence of alkyl groups on both sides of the bisphenol A skeleton acts as a soft segment in the polymer, and the color developability and image strength during toner fixing are improved. Of the bisphenol A alkylene oxide adducts, those having an ethylene group or a propylene group are preferably used.
[0038]
Among the monomers constituting the polyester resin in the present invention, examples of the acid monomer include trifunctional or higher polyfunctional monomers, such as maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, and isophthalic acid. Acids, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, or alkenyl succinic acids such as n-dodecenyl succinic acid, n-dodecyl succinic acid, or alkyl succinic acids, anhydrides of these acids Products, alkyl esters, other divalent carboxylic acids, and 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4 -Butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1 3-dicarboxyl-2-methyl-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, empole trimer acid, and anhydrides thereof, alkyl esters, alkenyl esters , Aryl esters, and other trivalent or higher carboxylic acids.
[0039]
Specific examples of the acid constituting the alkyl ester, alkenyl ester or aryl ester described above include 1,2,4-benzenetricarboxylic acid, trimethyl 1,2,4-benzenetricarboxylate, 1,2,4- Benzene tricarboxylate triethyl, 1,2,4-benzene tricarboxylate tri n-butyl, 1,2,4-benzene tricarboxylate isobutyl, 1,2,4-benzene tricarboxylate tri n-octyl, 1,2,4- Examples thereof include tri-2-ethylhexyl benzenetricarboxylate, tribenzyl 1,2,4-benzenetricarboxylate, and tris (4-isopropylbenzyl) 1,2,4-benzenetricarboxylate.
[0040]
The relationship between the chargeability of the polyester resin and the acid value is almost proportional, and it is known that the higher the acid value, the greater the negative chargeability of the resin. At the same time, it affects the environmental stability of the charge. . That is, when the acid value is high, the charge amount is high under low temperature and low humidity, and the charge amount is low under high temperature and high humidity, resulting in large changes in background stains, image density, and color reproducibility, making it difficult to maintain high image quality. . Therefore, the acid value of the polyester resin is preferably 20 KOHmg / g or less, and more preferably 5 KOHmg / g or less.
[0041]
As the polyol resin used in the present invention, the end of the epoxy resin is capped from the viewpoints of environmental stability of charging, fixing stability, color reproducibility, gloss stability, anti-curling property after fixing, and the main chain. Those having a polyoxyalkylene moiety are preferred. For example, it can be obtained by reacting an epoxy resin having a glycidyl group at both ends and an alkylene oxide adduct of a dihydric phenol having both glycidyl groups with a dihalide, isocyanate, diamine, diol, polyhydric phenol or dicarboxylic acid. Of these, it is most preferable to react divalent phenol in terms of reaction stability. Moreover, it is also preferable to use polyhydric phenols and polyhydric carboxylic acids in combination with dihydric phenols as long as they do not gel. The acid value of the polyol resin is preferably 20 KOH mg / g or less, more preferably 5 KOH mg / g or less.
[0042]
Examples of the alkylene oxide adducts of dihydric phenols having both glycidyl groups constituting the polyol resin used in the present invention are as follows. Examples include reaction products of ethylene oxide, propylene oxide, butylene oxide, and mixtures thereof with bisphenols such as bisphenol A and bisphenol F. The obtained adduct may be used after glycidylation with epichlorohydrin or β-methylepichlorohydrin. In particular, glycidyl ether of an alkylene oxide adduct of bisphenol A represented by the following general formula (1) is preferable.
[0043]
[Chemical 1]

[0044]
A method of mixing toner particles with inorganic powders such as various metal oxides for the purpose of improving the flow characteristics and charging characteristics of the toner has been proposed. These inorganic powders are called external additives. It is. If necessary, the surface of the inorganic powder may be treated with a specific silane coupling agent, titanate coupling agent, silicone oil, organic acid, etc., or a specific resin may be coated to improve the hydrophobicity or charging characteristics of the surface of the inorganic powder. The method of doing etc. is also proposed. As the inorganic powder, for example, silicon dioxide (silica), titanium dioxide (titania), aluminum oxide, zinc oxide, magnesium oxide, cerium oxide, iron oxide, copper oxide, tin oxide and the like are known. In particular, silica particles obtained by reacting silica or titanium oxide fine particles with an organosilicon compound such as dimethyldichlorosilane, hexamethyldisilazane, or silicone oil to replace the silanol groups on the surface of the silica fine particles with organic groups to make them hydrophobic are used.
[0045]
The volume average particle diameter of the toner particles is 4 to 9 μm, and the ratio of the volume average diameter Dv to the number average diameter Dn, Dv / Dn, is preferably 1.5 or less. Less.
[0046]
The toner for electrophotography of the present invention can be provided as a one-component developer, or can be provided as a two-component developer by mixing with a carrier. Regardless of the developer used in the present invention, the toner has effects such as stable toner charge amount and transport amount, high image quality, in-machine contamination and prevention of photoconductor filming even after long-term use. Furthermore, the present invention may be provided as a container enclosing these developers or may be provided as an image forming apparatus.
[0047]
When the toner of the present invention is used as a two-component developer, as the carrier, a carrier used as a coating agent such as an acrylic resin, a fluorine resin, or a silicone resin is known. Excellent from a viewpoint.
[0048]
Further, according to the present invention, a latent image forming step of forming a latent image on the latent image holding member, a developing step of developing the latent image using a developer on the developer carrying member, and the developed toner image as a transfer member In the image forming method having a transfer step for transferring the toner image and a fixing step for heating and fixing the toner image on the transfer member, the one-component developer or the two-component developer of the present invention is used as the developer. An image forming method is provided.
[0049]
Further, according to the present invention, in the above image forming method, the developing step further forms a thin layer of the developer on the developer carrying member, and develops in contact or non-contact with the latent image holding member. An image forming method is provided.
[0050]
Furthermore, in the image forming method using the one-component developer, the latent image formed in the latent image forming step is an electrostatic latent image divided into multiple colors, and the latent image holding member Are a plurality of latent image holders corresponding to the colors of the electrostatic latent image, and in the developing step, the developer is a plurality of developers corresponding to the colors of the electrostatic latent image, and A developer blade for uniformly regulating the developer carrying member and the layer thickness of the developer supplied onto the developer carrying member on the plurality of latent image holding members respectively corresponding to the plurality of developers. Development is performed using a plurality of multicolor developing devices provided, and in the transfer step, the transfer body is brought into contact with the surfaces of a plurality of latent image holders, and the developed toner images are sequentially electrostatically applied to the transfer body by a transfer unit. An image forming method characterized by transferring is provided.
[0051]
Furthermore, in the image forming method using the two-component developer, the latent image formed in the latent image forming step is an electrostatic latent image divided into multiple colors, and the latent image holding member Are a plurality of latent image holders corresponding to the colors of the electrostatic latent image, and in the developing step, the developer is a plurality of developers corresponding to the colors of the electrostatic latent image, and A plurality of latent image holding bodies respectively corresponding to the plurality of developers, and a plurality of developing blades for uniformly regulating the layer thickness of the developer supplied onto the developing rolls. Development is performed using a multicolor developing device, and in the transfer step, the transfer body is brought into contact with the surface of a plurality of latent image holders, and the developed toner images are sequentially electrostatically transferred to the transfer body by a transfer unit. An image forming method is provided.
[0052]
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, yellow lead , Titanium yellow, Polyazo yellow, Oil yellow, Hansa yellow (GR, A, RN, R), Pigment yellow L, Benzidine yellow (G, GR), Permanent yellow (NCG), Vulcan fast yellow (5G, R), Tartrazine lake, quinoline yellow lake, anthrazan yellow BGL, isoindolinone yellow, bengara, red lead, lead vermilion, cadmium red, cadmium mercurial red, antimon vermilion, permanent red 4R, para red, fise red, parachlor ortho nitro Aniri Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Tolujing Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, thioindigo maroon, oil red, quinacridone red, pyrazolone red, polyazo , Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo, Ultramarine Blue, Bitumen, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chrome Oxide, Pyridian, Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalocyanine Green, anthraquinone green, titanium oxide, zinc white, lithopone and mixtures thereof can be used. The amount used is generally 0.1 to 50 parts by weight per 100 parts by weight of the binder resin.
[0053]
In order to impart releasability to the manufactured developer, it is preferable to include a wax in the manufactured developer. The wax has a melting point of 40 to 120 ° C., and preferably 50 to 110 ° C. When the melting point of the wax is excessive, the fixing property at a low temperature may be insufficient. On the other hand, when the melting point is excessively low, the offset resistance and durability may be decreased. The melting point of the wax can be obtained by differential scanning calorimetry (DSC). That is, the melting peak value when a sample of several mg is ripened at a constant temperature increase rate, for example, (10 ° C./min) is defined as the melting point.
[0054]
Examples of the wax that can be used in the present invention include solid paraffin wax, micro wax, rice wax, fatty acid amide wax, fatty acid wax, aliphatic monoketone, fatty acid metal salt wax, fatty acid ester wax, and partial kenne. Fatty acid ester wax, silicone varnish, higher alcohol, carnauba wax and the like. Also, polyolefins such as low molecular weight polyethylene and polypropylene can be used. Particularly, a polyolefin having a softening point of 70 to 150 ° C. by the ring and ball method is preferable, and a polyolefin having a softening point of 120 to 150 ° C. is more preferable. The amount of wax used is generally 0.5 to 20 parts by weight with respect to 100 parts by weight of the binder resin.
[0055]
Examples of the cleaning performance improver for removing the developer after transfer remaining on the photoreceptor or the primary transfer medium include, for example, fatty acid metal salts such as zinc stearate, calcium stearate, and stearic acid, such as polymethyl methacrylate fine particles, polystyrene fine particles. Examples thereof include polymer fine particles produced by soap-free emulsion polymerization and the like. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.
[0056]
DETAILED DESCRIPTION OF THE INVENTION
The method for producing the electrophotographic toner of the present invention and the full color image forming method using the toner of the present invention will be described below.
[0057]
(Toner production method)
The method for producing an electrophotographic toner of the present invention includes a step of mechanically mixing a developer component including at least a binder resin, a charge control agent, and a colorant, a step of melt-kneading, a step of pulverizing, and a classification. The manufacturing method which has a process to perform is applicable. In addition, in the mechanical mixing step and the melt-kneading step, a production method is also included in which powder other than particles that are products obtained in the pulverization or classification step is returned and reused.
[0058]
The powders (sub-products) other than the particles used as the product referred to here are fine particles and coarse particles other than the components used as the product having a desired particle size obtained in the pulverization step after the melt-kneading step, and a subsequent classification step. It means fine particles or coarse particles other than the components that are produced as products having a desired particle size. Such a by-product is mixed in the weight ratio of the other raw material 50 to the raw material and preferably from the other raw material 99 to the sub-product 50 in the mixing step and the melt-kneading step.
[0059]
The mixing step of mechanically mixing the developer component including the binder resin, the charge control agent, the colorant, and the by-product may be performed under normal conditions using a normal mixer using a rotating wing, and the like. There is no limit.
[0060]
When the above mixing process is completed, the mixture is then charged into a kneader and melt-kneaded. As the melt-kneader, a uniaxial or biaxial continuous kneader or a batch kneader using a roll mill can be used as described above in order to make the dispersed particle diameter within an appropriate range. For example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type extruder manufactured by Toshiba Machine Co., Ltd., twin screw extruder manufactured by Kay Sea Kay Co., Ltd., PCM type twin screw extruder manufactured by Ikekai Iron Works Co., Ltd. A kneader or the like is preferably used. It is important that this melt-kneading is performed under appropriate conditions that do not cause the molecular chains of the binder resin to be broken. Specifically, the melt kneading temperature should be performed with reference to the softening point of the binder resin. If the temperature is too low than the softening point, cutting is severe, and if the temperature is too high, dispersion does not proceed.
[0061]
When the above melt-kneading process is completed, the kneaded product is then pulverized. In this pulverization step, it is preferable to first coarsely pulverize and then finely pulverize. At this time, a method of pulverizing by colliding with a collision plate in a jet stream, pulverizing particles by colliding with each other in a jet stream, or pulverizing with a narrow gap between a rotor and a stator that rotate mechanically is preferably used. .
[0062]
After the pulverization step is completed, the pulverized product is classified in an air stream by centrifugal force or the like, thereby producing a toner having a predetermined particle size, for example, an average particle size of 5 to 20 μm.
In addition, when preparing the toner, in order to improve the flowability, storage stability, developability, and transferability of the developer, the hydrophobic silica fine powder listed above for the toner produced as described above, etc. Inorganic fine particles may be added and mixed. For mixing external additives, a general powder mixer is used, but it is preferable to equip a jacket or the like to adjust the internal temperature. In order to change the load history applied to the external additive, the external additive may be added in the middle or gradually. Of course, you may change the rotation speed of a mixer, rolling speed, time, temperature, etc. A strong load may be given first, then a relatively weak load, and vice versa. Examples of the mixing equipment that can be used include a V-type mixer, a rocking mixer, a Ladige mixer, a Nauter mixer, a Henschel mixer, and the like.
[0063]
In addition, when the toner of the present invention is used for a two-component developer, it may be used by mixing with a magnetic carrier, and the content ratio of the carrier and the toner in the developer is 1 to 100 parts by weight of the carrier. 10 parts by weight is preferred. As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, magnetic resin carrier having a particle diameter of about 20 to 200 μm can be used.
[0064]
Examples of the carrier coating material include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, and epoxy resin. Polyvinyl and polyvinylidene resins such as acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins and styrene acrylic copolymer resins, Halogenated olefin resins such as vinyl, polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, polyhexafluoro Propylene resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, tetrafluoroethylene and vinylidene fluoride and non- Although fluoro terpolymers such as terpolymers, etc. and monomers including can be used, the silicone resin is excellent in terms of developer life.
[0065]
Moreover, you may contain electrically conductive powder etc. in said coating resin as needed. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide or the like can be used. These conductive powders preferably have an average particle diameter of 1 μm or less. When the average particle diameter is larger than 1 μm, it becomes difficult to control electric resistance.
[0066]
(Full color image development method)
In addition, in the image forming method of the present invention, particularly in the non-magnetic one-component development system, the full-color toner using the electrophotographic toner of the present invention is sequentially developed many times and sequentially superimposed on the transfer medium. By using the non-magnetic one-component full-color process for transferring, the remarkable effect of the electrophotographic toner of the present invention can be obtained particularly on the halftone uniform reproducibility.
[0067]
The full-color non-magnetic one-component image forming method using the image forming method of the present invention is a plurality of multi-color developing devices provided with a developing roller and a developing blade that uniformly regulates the layer thickness of the developer supplied onto the developing roller. Thus, the electrostatic latent image divided on each color formed on the photosensitive member by the conductive brush charger and the exposure device is sequentially developed with a developer corresponding to each color and transferred to a transfer medium. In this case, it is preferable to develop by a reversal development method in which the polarity of the electrostatic latent image on the photoreceptor and the polarity of the non-magnetic one-component developer are the same. Further, it is preferable that development is performed by causing the electrostatic latent image on the photosensitive member and the developing roller to directly contact each other and rotating the developing roller at a higher speed than the photosensitive member.
[0068]
FIG. 1 is a schematic configuration diagram of an image forming apparatus as an example to which the image forming method of the present invention is applied. The image forming method implemented by the apparatus shown in FIG. 1 includes a latent image forming step of forming an electrostatic latent image on an organic photosensitive drum or belt as a photosensitive member as a latent image holding member, and developing the electrostatic latent image. Development process for developing using developer on developing roller as agent carrier, transfer process for primary transfer of developed toner image onto intermediate transfer body and secondary transfer onto transfer paper, toner image on transfer paper And a fixing step of fixing by heating with a heat roller or a belt, and an image is formed using a one-component or two-component developer using the electrophotographic toner of the present invention. In the present invention, in the development step, an image is formed by forming a thin layer of the developer on the developer carrying member and developing with or without contact with the latent image holding member.
[0069]
Furthermore, the image forming method of the present invention can also be applied to the apparatus shown in FIG. A plurality of multicolor developing devices having a developing roller as shown in FIG. 2 and a doctor roller that uniformly regulates the layer thickness of the developer supplied onto the developing roller can produce a plurality of colors formed on the latent image holding member. The divided electrostatic latent image is developed on a plurality of latent image holders corresponding to the respective colors with a developer corresponding to each color, and a transfer unit is brought into contact with the latent image holding surface via a transfer material. The toner images are sequentially electrostatically transferred onto the transfer material. In this method, an image is formed using a one-component or two-component developer using the electrophotographic toner of the present invention.
[0070]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to only these examples. In the following examples, parts and% are based on weight unless otherwise specified. In the following, first, Synthesis Examples 1 to 7 of the resin negative charge control agent used in the electrophotographic toner of the present invention, and Synthesis Example 8 of the charge control agent not containing an acrylate ester and / or a methacrylic acid ester monomer are described. Describe. Next, synthesis examples of polyester resins A to D and polyol resins A to B, which are binder resins used in the electrophotographic toner of the present invention, will be described. Thereafter, as Example 1, a production example of four-color toners using these materials and Toner Production Example 1 (Toner No. T1) are described, and image formation using the toner and evaluation method of the obtained image are described. And the evaluation result is described. In the following Examples 2-12 and Comparative Examples 1-3, the obtained No. An image is created by using toners of T2 to T15 in order, and the evaluation results are described.
[0071]
(Synthesis example of resin negative charge control agent)
Synthesis example 1
350 parts of 3,4-dichlorophenylmaleimide and 100 parts of 2-acrylamido-2-methylpropanesulfonic acid were copolymerized for 8 hours with ditertiary butyl peroxide as an initiator under the boiling point in dimethylformaldehyde (DMF). Next, 500 parts of n-butyl acrylate and 50 parts of styrene were added, and after graft polymerization for 4 hours using ditertiary butyl peroxide as an initiator, DMF was distilled off with a vacuum dryer, and the volatile content was 1.0% by weight, Volume resistance 10.5 log Ω · cm, weight average molecular weight 10,000, apparent viscosity 10⁴P (10⁴P = 10⁴The charge control resin A having a temperature of 96 ° C. was obtained.
[0072]
Synthesis example 2
600 parts of m-nitrophenylmaleimide and 100 parts of perfluorooctanesulfonic acid were copolymerized for 8 hours with ditertiary butyl peroxide as an initiator under the boiling point in dimethylformaldehyde (DMF). Next, 250 parts of 2-ethylhexyl acrylate and 30 parts of styrene were added, and after graft polymerization for 4 hours using ditertiary butyl peroxide as an initiator, DMF was distilled off with a vacuum dryer, and the volatile content was 3.8% by weight. Volume resistance 9.5 log Ω · cm, weight average molecular weight 5500, apparent viscosity 10⁴P (10⁴P = 10⁴g / cm · s) was obtained as a charge control resin B having a temperature of 85 ° C.
[0073]
Synthesis example 3
500 parts of 3,4-dichlorophenylmaleimide and 150 parts of 2-acrylamido-2-methylpropanesulfonic acid were copolymerized for 8 hours with ditertiary butyl peroxide as an initiator at the boiling point in dimethylformaldehyde (DMF). Next, 350 parts of n-butyl acrylate and 250 parts of α-methylstyrene were added and graft polymerization was carried out for 4 hours using ditertiary butyl peroxide as an initiator. % By weight, volume resistance 11.5 log Ω · cm, weight average molecular weight 95000, apparent viscosity 10⁴P (10⁴P = 10⁴g / cm · s) was obtained as a charge control resin C having a temperature of 110 ° C.
[0074]
Synthesis example 4
400 parts of 3,4-dichlorophenylmaleimide and 200 parts of perfluorooctanesulfonic acid were copolymerized for 8 hours with ditertiary butyl peroxide as an initiator under the boiling point in dimethylformaldehyde (DMF). Next, 300 parts of n-butyl acrylate was added, and graft polymerization was carried out for 4 hours using ditertiary butyl peroxide as an initiator. Then, DMF was distilled off with a vacuum dryer, the volatile content was 1.7% by weight, the volume resistance was 10.3 logΩ・ Cm, weight average molecular weight 50000, apparent viscosity 10⁴P (10⁴P = 10⁴The charge control resin D having a temperature of 105 ° C. was obtained.
[0075]
Synthesis example 5
400 parts of 3,4-dichlorophenylmaleimide and 100 parts of 2-acrylamido-2-methylpropanesulfonic acid were copolymerized at a boiling point in dimethylformaldehyde (DMF) for 8 hours using ditertiary butyl peroxide as an initiator. Next, 500 parts of n-butyl acrylate and 100 parts of styrene were added, and graft polymerization was carried out for 4 hours using ditertiary butyl peroxide as an initiator. Then, DMF was distilled off with a vacuum dryer, and the volatile content was 4.8% by weight. Volume resistance 9.6 log Ω · cm, weight average molecular weight 30000, apparent viscosity 10⁴P (10⁴P = 10⁴g / cm · s) was obtained as a charge control resin E having a temperature of 101 ° C.
[0076]
Synthesis Example 6
400 parts of 3,4-dichlorophenylmaleimide and 200 parts of 2-acrylamido-2-methylpropanesulfonic acid were copolymerized for 8 hours with ditertiary butyl peroxide as an initiator at the boiling point in dimethylformaldehyde (DMF). Next, 200 parts of n-butyl acrylate and 400 parts of styrene were added and dissolved, and then DMF was distilled off using a vacuum drier. The apparent viscosity is 10⁴P (10⁴P = 10⁴g / cm · s) was obtained as a charge control resin F having a temperature of 110 ° C.
[0077]
Synthesis example 7
450 parts of 3,4-dichlorophenylmaleimide and 150 parts of perfluorooctane sulfonic acid were copolymerized for 3 hours with ditertiary butyl peroxide as an initiator at the boiling point in dimethylformaldehyde (DMF). Next, 500 parts of methyl acrylate was added, and graft polymerization was carried out for 4 hours using ditertiary butyl peroxide as an initiator. Then, DMF was distilled off with a vacuum dryer, and the volatile content was 5.2% by weight. , Weight average molecular weight 2800, apparent viscosity 10⁴P (10⁴P = 10⁴g / cm · s) was obtained as a charge control resin G having a temperature of 80 ° C.
[0078]
Synthesis Example 8
After copolymerizing 60 parts of sodium styrenesulfonate, 440 parts of nitrophenylmaleimide and 500 parts of perfluoroalkylethyl methacrylate under a boiling point in dimethylformaldehyde (DMF) for 3 hours using ditertiary butyl peroxide as an initiator, DMF was dried under reduced pressure. The charge control resin H having a volatile content of 1.2% by weight, a volume resistance of 10.2 log Ω · cm, and a softening point of 137 ° C. was obtained.
[0079]
(Synthesis example of polyester resin)
Synthesis example 1
In a four-necked separable flask with a stirrer, thermometer, nitrogen inlet, flow-down condenser, and condenser, 740 g of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxy Esterification catalyst of 300 g of ethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 466 g of dimethyl terephthalate, 80 g of isododecenyl succinic anhydride, and 114 g of tri-n-butyl 1,2,4-benzenetricarboxylate Added with. Under a nitrogen atmosphere, the temperature was raised to 210 ° C. in the first half, and the reaction was carried out with stirring at 210 ° C. under reduced pressure in the second half. A polyester resin having an acid value of 2.3 KOH mg / g, a hydroxyl value of 28.0 KOH mg / g, a softening point of 106 ° C., and a Tg of 62 ° C. was obtained (hereinafter referred to as polyester resin A).
[0080]
Synthesis example 2
725 g of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 165 g of polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 500 g of terephthalic acid, 130 g of isododecenyl succinic anhydride and 170 g of triisopropyl 1,2,4-benzenetricarboxylate were added to the flask along with the esterification catalyst. These were reacted in the same apparatus and the same formulation as in Synthesis Example 1 to obtain a polyester resin having an acid value of 0.5 KOH mg / g, a hydroxyl value of 25.0 KOH mg / g, a softening point of 109 ° C., and a Tg of 63 ° C. Resin B).
[0081]
Synthesis example 3
650 g of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 650 g of polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 515 g of isophthalic acid, 70 g of isooctenyl succinic acid and 80 g of 1,2,4-benzenetricarboxylic acid were added to the flask together with the esterification catalyst. These were reacted in the same apparatus and the same formulation as in Synthesis Example 1 to obtain a polyester resin having an acid value of 19.5 KOH mg / g, a hydroxyl value of 35.0 KOH mg / g, a softening point of 110 ° C., and a Tg of 60 ° C. Resin C).
[0082]
Synthesis example 4
714 g of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 663 g of polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 648 g of isophthalic acid, 150 g of isooctenyl succinic acid and 100 g of 1,2,4-benzenetricarboxylic acid were added to the flask together with the esterification catalyst. These were reacted in the same apparatus and the same formulation as in Synthesis Example 1 to obtain a polyester resin having an acid value of 21.0 KOHmg / g, a hydroxyl value of 24.0 KOHmg / g, a softening point of 128 ° C., and a Tg of 65 ° C. Resin D).
[0083]
(Synthesis example of polyol resin)
Synthesis example 1
In a separable flask equipped with a stirrer, a thermometer, a nitrogen inlet, and a cooling tube, 378.4 g of a low molecular weight bisphenol A type epoxy resin (number average molecular weight: about 360), a high molecular weight bisphenol A type epoxy resin (number average molecular weight: about 2700) 86.0 g, glycidylated product of bisphenol A-type propylene oxide adduct (n + m: about 2.1 in the above general formula (1)) 191.0 g, bisphenol F 274.5 g, p-cumylphenol 70.1 g, xylene 200 g was added. The temperature was raised to 70-100 ° C. in a nitrogen atmosphere, 0.1839 g of lithium chloride was added, the temperature was further raised to 160 ° C., xylene was distilled off under reduced pressure, and polymerization was performed at a reaction temperature of 180 ° C. for 7-9 hours. Thus, a polyol resin having an acid value of 0.0 KOH mg / g, a hydroxyl value of 70.0 KOH mg / g, a softening point of 110 ° C., and a Tg of 62 ° C. was obtained (hereinafter referred to as polyol resin A).
[0084]
Synthesis example 2
Using the apparatus of Synthesis Example 1, 205.3 g of a low molecular weight bisphenol A type epoxy resin (number average molecular weight: about 360), 54.0 g of a high molecular weight bisphenol A type epoxy resin (number average molecular weight: about 3000), bisphenol A type 432.0 g of a glycidylation product of propylene oxide adduct (n + m: about 2.2 in the general formula (1)), bisphenol F282.7 g, p-cumylphenol 26.0 g, and xylene 200 g were added. The temperature was raised to 70-100 ° C. under a nitrogen atmosphere, 0.183 g of lithium chloride was added, the temperature was further raised to 160 ° C., xylene was distilled off under reduced pressure, and polymerization was performed at a reaction temperature of 180 ° C. for 6-8 hours. Thus, a polyol resin having an acid value of 0.0 KOH mg / g, a hydroxyl value of 58.0 KOH mg / g, a softening point of 105 ° C., and a Tg of 58 ° C. was obtained (hereinafter referred to as polyol resin B).
[0085]
Example 1
In this example, an electrophotographic toner T1 was produced as follows, and an image was formed using the toner T1 as described below and evaluated.
[0086]

Stir well with a flasher. To this, 1200 parts of polyester resin A was added, kneaded at 150 ° C. for 30 minutes, 1000 parts of xylene were added, kneaded for 1 hour, water and xylene were removed, rolled and cooled, and pulverized with a pulverizer to obtain a master batch pigment.
[0087]
100 parts of polyester resin A
5 parts of the above master batch
Charge control resin A 5 parts
The above materials were mixed with a Henschel mixer, melt-kneaded with a two-roll mill, and the kneaded product was rolled and cooled. After that, a collision plate type pulverizer (I-2 type mill; manufactured by Nippon Pneumatic Kogyo Co., Ltd.) using a jet mill and a wind classifier (DS classifier; manufactured by Nihon Pneumatic Kogyo Co., Ltd.) using a swirling flow are performed. Black colored particles having a size of 2 μm and a volume average diameter of 6.5 μm (Dv / Dn = 1.3) were obtained. The pulverization amount per unit time at that time was 2.3 kg / H.
[0088]

Stir well with a flasher. To this, add 1200 parts of polyester resin A, knead at 150 ° C for 30 minutes, add 1000 parts of xylene, knead for another hour, remove water and xylene, cool by rolling, pulverize with a pulverizer, and pass twice with 3 rolls. To obtain a master batch pigment.
[0089]
100 parts of polyester resin A
5 parts of the above master batch
Charge control resin A 5 parts
The above materials were mixed with a Henschel mixer, melt-kneaded with a two-roll mill, and the kneaded product was rolled and cooled. Thereafter, pulverization and classification were performed in the same manner as in the black colored particle production example to obtain yellow colored particles having a number average diameter of 5.4 μm and a volume average diameter of 6.6 μm (Dv / Dn = 1.2). The pulverization amount per unit time at that time was 2.3 kg / H.
[0090]

Stir well with a flasher. To this, add 1200 parts of polyester resin A, knead at 150 ° C for 30 minutes, add 1000 parts of xylene, knead for 1 hour, remove water and xylene, cool by rolling, pulverize with a pulverizer, and pass twice with a three-roll mill. A master batch pigment was obtained.
[0091]
100 parts of polyester resin A
5 parts of the above master batch
Charge control resin A 5 parts
The above materials were mixed with a Henschel mixer, melt-kneaded with a two-roll mill, and the kneaded product was rolled and cooled. Thereafter, pulverization and classification were performed in the same manner as in the black colored particle production example to obtain magenta colored particles having a number average diameter of 5.2 μm and a volume average diameter of 6.8 μm (Dv / Dn = 1.3). The pulverization amount per unit time at that time was 2.3 kg / H.
[0092]

Stir well with a flasher. To this, add 1200 parts of polyester resin A, knead at 150 ° C. for 30 minutes, add 1000 parts of xylene, knead for 1 hour, remove water and xylene, cool by rolling, pulverize with a pulverizer, and pass twice with a three-roll mill. A master batch pigment was obtained.
[0093]
100 parts of polyester resin A
3 parts of the above master batch
Charge control resin A 5 parts
The above materials were mixed with a Henschel mixer, melt-kneaded with a two-roll mill, and the kneaded product was rolled and cooled. Thereafter, pulverization and classification were performed in the same manner as in the black colored particle production example to obtain cyan colored particles having a number average diameter of 5.9 μm and a volume average diameter of 6.9 μm (Dv / Dn = 1.2). The pulverization amount per unit time at that time was 2.3 kg / H.
[0094]
5) Mixing with external additives
To 100 parts by weight of the obtained four colored particles, 1.0 part by weight of hydrophobic silica (Wacker HDK H2000) and 1.0 part by weight of hydrophobic silica (Aerosil RX-50, Nippon Aerosil Co., Ltd.) as external additives 4-color electrophotography by adding 0.5 parts by weight of hydrophobic titanium oxide (Taika MT-150AI), mixing with a Henschel mixer, and removing coarse particles and aggregates by passing through a mesh with an opening of 100 μm. Toner T1 was obtained.
[0095]
When image evaluation is performed using the toner produced as described above for a two-component developer, a ferrite carrier having an average particle diameter of 50 μm coated with a silicone resin with an average thickness of 0.3 μm is used, and 100 parts by weight of the carrier is used. On the other hand, 5 parts by weight of each color toner was uniformly mixed and charged using a tumbler mixer of a type in which the container was rolled and stirred to prepare a developer.
[0096]
(Toner evaluation machine)
The resulting toner is a full-color system in which the four-color developing unit sequentially develops each non-magnetic one-component developer on one belt photoreceptor, sequentially transfers it to an intermediate transfer member, and transfers the four colors onto paper or the like at once. Laser printer Ypsio 5000 (made by Ricoh Co., Ltd., evaluation machine A) Full-color tandem system that has a non-magnetic one-component development unit for four colors and a photoconductor for four colors and transfers them sequentially onto transfer paper Each color is developed on one drum-shaped photoconductor by an LED printer GL8300 (manufactured by Fujitsu Ltd., evaluation machine B) and a four-color developing unit having a two-component developer, sequentially transferred to an intermediate transfer body, transfer paper, etc. A full-color laser copier Imagio Color 2800 (made by Ricoh Co., Ltd., evaluation machine C) and a full-color laser printer Ipsio Color 8000 (Rico) Company, Ltd., was evaluated by to) and the evaluation machine D. The developing units of the evaluation machines A and B are equipped with a developing roller made of an elastic material and a non-magnetic one-component developing unit made of a stainless steel blade with a regulated layer thickness. All four types of evaluation machines are reversal development systems in which the polarity of the electrostatic latent image on the photoreceptor and the polarity of the non-magnetic one-component developer are the same. The combinations of the examples or comparative examples and the evaluation machines used are shown in Tables 2-1 to 2-3 described later.
[0097]
(Evaluation item)
In each item, an image chart having a 5% image area was continuously run up to 100,000 sheets, and then the evaluation described below was performed. The evaluation results are shown in Table 2 together with the results of Examples 2 to 12 and Comparative Examples 1 to 3 described later.
[0098]
1) Image density
After outputting the solid image, the image density was measured by X-Rite (manufactured by X-Rite). This was measured at five points for each color alone, and the average was obtained for each color.
[0099]
2) Stain dirt
The blank image was stopped during development, the developer on the developed photoreceptor was tape transferred, and the difference from the image density of the untransferred tape was measured with a 938 spectrocytometer (X-Rite).
[0100]
3) Filming
The presence or absence of toner filming on the developing roller or the photoreceptor was observed. ○ indicates no filming, Δ indicates filming on streaks, and × indicates filming as a whole.
[0101]
4) Lines
The presence or absence of the occurrence of color streaks on the toner thin layer and the image on the developing roller was observed. ○ indicates almost no color streaks, Δ indicates several streaks, and x indicates overall color streaks.
[0102]
5) Physical property measurement
5-1) [Particle size]
The particle diameter of the toner was measured using a particle size measuring device “Coulter Counter TAII” manufactured by Coulter Electronics Co., Ltd., with an aperture diameter of 100 μm. The volume average particle diameter and the number average particle diameter were determined by the particle size measuring instrument.
[0103]
5-2) [Charge amount]
In the case of a two-component developer: 6 g of the developer was weighed, charged into a metal cylinder that can be sealed, and blown to obtain the charge amount. The toner concentration was adjusted to 4.5 to 5.5% by weight.
In the case of one-component toner: The toner was conveyed onto a developing roller (sleeve) and measured by a suction tribo measurement method in each environment. The high temperature and high humidity was 32 ° C. and 80 RH%, and the low temperature and low humidity was 10 ° C. and 30 RH%.
[0104]
5-3) Dispersion particle diameter of resin negative charge control agent
After the toner was cut into ultrathin sections and stained with ruthenium oxide, the dispersion state was observed using a photographic image magnified 5000 to 20000 times with a transmission electron microscope H-800 manufactured by Hitachi, Ltd.
[0105]
6) Transparency
Samples were prepared from OHP sheets at 160 ° C. with a fixing speed of 90 mm / s. This was measured for transparency using a haze meter (Suga Test Machine Co., Ltd.). A haze degree of 15% or less was evaluated as ◯, a haze degree of less than 30% was evaluated as Δ, and 30% or more was evaluated as ×.
[0106]
7) Volatile content of resin negative charge control agent
A sample of 1.5 to 2.0 g that has been pulverized into a 20 mesh pass is precisely weighed, left to stand in a circulating dryer at 150 ° C. (manufactured by Tabai) for 45 minutes, and then taken out. It was.
Volatiles (%) = (1-dry residue weight / sample weight) × 100
[0107]
8) Volume resistance of resin negative charge control agent
For example, about 500 kgf / cm of 3 g of resin powder sized using a sieve or the like²Pressurized, area 12.5cm²Using a commercially available dielectric loss measuring machine (manufactured by Ando Electric Co., Ltd., TR-10C type) molded into pellets with a thickness of about 1.8 to 2.2 mm, measurement is performed with a frequency of 1 KHz applied. The volume resistance was calculated from this.
[0108]
9) Productivity
As described above, the kneaded product is subjected to a collision plate type crusher using a jet mill (I-2 type mill; manufactured by Nippon Pneumatic Industry Co., Ltd.) and a wind classifier using a swirling flow (DS classifier; manufactured by Nippon Pneumatic Industry Co., Ltd.). Then, adjustment was made to obtain colored particles having a volume average diameter of 6.5 μm (Dv / Dn = 1.5 or less), and the amount of pulverization (Kg / H) per unit time was measured. If it is 2.0 (Kg / H) or more and there is no aggregation of raw materials or adhesion to piping, less than 2.0 (Kg / H), or aggregation of raw materials occurs or sticking to piping occurs Is x.
[0109]
Examples 2-12
As shown in Table 1 to be described later, the toner particle size, the charge control resin and its addition amount, and the binder resin were selected, and other than that, four color toners were produced in the same manner as in Example 1, and the toner No. T2 to T12. Thereafter, an image was formed using each toner, and the same evaluation as in Example 1 was performed. The results are shown in Tables 2-1 to 2-3 described later.
[0110]
Comparative Example 1
In Comparative Example 1, a toner (toner No. T13) was produced in the same manner as in Example 1 except that the addition amount of salicylic acid derivative zinc salt shown in Table 1 was used as the resin negative charge control agent. Bontron E-84 manufactured by Orient was used as the salicylic acid derivative zinc salt. Images were formed using this toner and evaluated in the same manner as in Example 1. The results are shown in Tables 2-1 to 2-3 below.
[0111]
Comparative Example 2
In Comparative Example 2, a toner (toner No. T14) was produced in the same manner as in Example 1 except that styrene / acrylic resin was used as the binder resin. The styrene / acrylic resin used was st-/ n-BMA, Mn5000, Mw12000, Tg61 ° C. Images were formed using this toner and evaluated in the same manner as in Example 1. The results are shown in Tables 2-1 to 2-3 below.
[0112]
Comparative Example 3
In Comparative Example 3, a toner (toner No. T15) was prepared in the same manner as in Example 1 except that the charge control agent resin H containing no acrylic acid ester and / or methacrylic acid ester monomer was used. ) Was manufactured. Images were formed using this toner and evaluated in the same manner as in Example 1. The results are shown in Tables 2-1 to 2-3 below.
[0113]
[Table 1]

[0114]
[Table 2]

[0115]
[Table 3]

[0116]
[Table 4]

[0117]
【The invention's effect】
According to the present invention, in any of the two-component and one-component color development methods, there is no filming on the photosensitive member, the developer layer thickness regulating member or the developing sleeve after continuous printing for a longer period of time than before, and the toner content is reduced. An electrophotographic toner that can stabilize charging and conveyance and maintain an image density equivalent to the initial image and a high-quality output image can be obtained. In addition, since there is little decrease in charge in continuous use, there are no problems such as fluctuations in image density, low developability, background stains, and toner scattering in the developing device, and an image with good color development and color reproducibility can be obtained. Because of this long-term durability, it is possible to extend the life of development units, photoconductor units, etc., and there are fewer recyclables and waste generated after use than before, and the user has to replace these imaging units. Can be reduced. Furthermore, an electrophotographic toner with good productivity can be obtained in the production process of kneading, pulverizing and classifying the toner.
[Brief description of the drawings]
FIG. 1 is a partial schematic configuration diagram of an example of an image forming apparatus to which an image forming method of the present invention is applied.
FIG. 2 is a partial schematic configuration diagram of an example of a multicolor developing device to which the image forming method of the present invention is applied.

Claims (22)

In an electrophotographic toner containing at least a binder resin, a colorant, and a negative charge control agent, the binder resin is a polyester and / or a polyol, and the negative charge control agent has an apparent viscosity of 10 ⁴ P ( 10 ⁴ P ( 10 ⁴ P = 10 ⁴ g / cm · s), a temperature of 85 to 110 ° C., and a volume resistance of 9.5 to 11.5 log Ω · cm, (1) a sulfonic acid-containing monomer, (2 An electrophotographic toner, which is a resin negative charge control agent comprising an aromatic monomer having an electron-withdrawing group and (3) an acrylate monomer and / or a methacrylic acid ester monomer as structural units.   The repeating unit of the sulfonic acid-containing monomer is 1 to 30% by weight with respect to the weight of the resin negative charge control agent, and the repeating unit of the aromatic monomer having the electron withdrawing group is 1 to 80 with respect to the weight of the resin negative charge control agent. 2. The weight percent, repeating unit of the acrylate monomer and / or methacrylic acid ester monomer is contained in a proportion of 10 to 80 wt% with respect to the weight of the resin negative charge control agent. Toner for electrophotography.   3. The electrophotographic toner according to claim 1, wherein the aromatic monomer having an electron withdrawing group is a phenylmaleimide substituted product or a phenylitaconimide substituted product substituted with a chlorine atom or a nitro group. .   The electrophotographic toner according to claim 1, wherein the negative charge control agent further contains an aromatic vinyl monomer as a constituent unit.   The electrophotographic toner according to claim 4, wherein the repeating unit of the aromatic vinyl monomer is contained in a proportion of 30% by weight or less based on the weight of the resin negative charge control agent. The electrophotographic toner according to any one of claims 1 to 5, characterized in that the volatile component contained in the resin negative charge control agent is 5 wt% or less. The electrophotographic toner according to any one of claims 1 to 6, weight-average molecular weight of the resin negative charge control agent characterized in that it is 5,000 to 100,000. Said resin negative charge control agent, an electrophotographic toner according to any one of claims 1 to 7, characterized in that it contains 0.1 to 20 wt% with respect to the base toner particles. The electrophotographic toner according to any one of claims 1 to 8, the acid value of the binder resin is equal to or less than 20 KOH mg / g. A one-component developer using the electrophotographic toner according to any one of claims 1 to 9 . A two-component developer using the electrophotographic toner and carrier according to any one of claims 1 to 9 . The two-component developer according to claim 11 , wherein the carrier is coated with a resin. A container containing the one-component developer according to claim 10 . Container containing a two-component developer according to claim 11 or 12. An image forming apparatus comprising a container containing the one-component developer according to claim 13 . An image forming apparatus comprising a container containing the two-component developer according to claim 14 . A latent image forming step of forming a latent image on the latent image holding member, a developing step of developing the latent image using a developer on the developer carrying member, and a transferred toner image is transferred onto the transfer member. An image forming method comprising: a transfer step; and a fixing step of heating and fixing a toner image on a transfer member, wherein the one-component developer according to claim 10 is used as the developer. 18. The image forming method according to claim 17 , wherein in the developing step, a thin layer of developer is formed on the developer carrying member, and development is performed in contact or non-contact with the latent image holding member. In the latent image forming step, the formed latent image is an electrostatic latent image divided into multiple colors, and the latent image holding body holds a plurality of latent images corresponding to the colors of the electrostatic latent image. And in the developing step, the developer is a plurality of developers each corresponding to the color of the electrostatic latent image, and the electrostatic latent image is converted into a plurality of latent images corresponding to the plurality of developers, respectively. Developing on the image carrier using a plurality of multicolor developing devices provided with a developer carrying member and a developing blade for uniformly regulating the layer thickness of the developer supplied onto the developer carrying member, and the transfer step The image formation according to claim 17 or 18 , wherein the transfer body is brought into contact with a plurality of latent image holder surfaces, and the developed toner images are sequentially electrostatically transferred to the transfer body by a transfer unit. Method. A latent image forming step of forming a latent image on the latent image holding member, a developing step of developing the latent image using a developer on the developer carrying member, and a transferred toner image is transferred onto the transfer member. An image forming method comprising: a transfer step; and a fixing step of heating and fixing a toner image on a transfer member, wherein the two-component developer according to claim 11 or 12 is used as the developer. 21. The image forming method according to claim 20 , wherein in the developing step, a thin layer of the developer is formed on the developer carrying member, and development is performed in contact or non-contact with the latent image holding member. In the latent image forming step, the formed latent image is an electrostatic latent image divided into multiple colors, and the latent image holding body holds a plurality of latent images corresponding to the colors of the electrostatic latent image. And in the developing step, the developer is a plurality of developers each corresponding to the color of the electrostatic latent image, and the electrostatic latent image is converted into a plurality of latent images corresponding to the plurality of developers, respectively. On the image carrier, development is performed using a plurality of multicolor developing devices provided with a developing roll and a developing blade that uniformly regulates the layer thickness of the developer supplied onto the developing roll. The image forming method according to claim 20 or 21 , wherein the transfer member is brought into contact with the surface of the latent image holding member, and the developed toner images are sequentially electrostatically transferred onto the transfer member by a transfer unit.

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