JP4393725B2 - Yellow toner and image forming apparatus - Google Patents

Description

（ここでＲは、下記化２で表されるアルキレン基を表す。また、ｎ、ｍは繰り返し単位数であり、各々１以上であってｎ＋ｍ＝２〜６である。）
【００５７】
【化２】

【００５８】
本発明のトナーにおいては、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の比がＤｖ／Ｄｎ≦１．４であることにより初期画像品質との差異が少なくなる。Ｄｖ／Ｄｎ＞１．４の場合は現像ローラ及び薄層形成部材へのトナーフィルミングが発生しやすい。また、経時でのトナー粒径分布変動が大きく、帯電量の変動が発生し、画像濃度変動が発生する。また、Ｄｖ／Ｄｎは１．１以上であることが好ましい。
【００５９】
着色剤としてのＣ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ１８０に分類される化合物の使用量は一般にバインダー樹脂１００重量部に対し０．１〜１０重量部である。該着色剤は帯電発生効果もあり、帯電制御剤を添加しないトナーでも、帯電制御剤を添加したトナーと同等の帯電量を発生する。ただし、帯電制御剤を添加しない場合は経時の帯電保持能力が低下してしまう。また、Ａ／Ｂの上限値は１．２であることが好ましい。
【００６０】
トナーの外添剤未処理品の帯電特性が、下記式（ａ）を満足することが好ましい。Ａ／Ｂ＜０．８の場合は、経時でトナー帯電上昇により画像濃度低下を発生し、さらには帯電上昇により現像剤担持体上にトナー薄層形成量が過多になり、地肌汚れを発生してしまう。
Ａ／Ｂ≧０．８ ・・・・・・・・・・・（ａ）
〔Ａ：不飽和帯電量 Ｂ：飽和帯電量〕
ここで、Ａ：不飽和帯電量とは、下記実施例に示すトナーの帯電量の測定方法により、ブローオフ測定時のＴＣが安定する最小の撹拌時間でのトナー帯電量を示し、また、Ｂ：飽和帯電量とは前記トナーの帯電量の測定方法により、撹拌時間をのばしていったときの帯電量が飽和に達した時のトナーの帯電量を示す。
【００６１】
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。前記ワックスは、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ツト性、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。
【００６２】
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など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など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。
【００６３】
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、ステアリン酸など脂肪酸金属塩、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などのソープフリー乳化重合などによって製造された、ポリマー微粒子などを挙げることができる。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。
【００６４】
本発明の外部添加剤としては、無機微粒子や有機微粒子等の公知の外部添加剤を用いることができるが、その中でも、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、外添剤と呼ばれている。
【００６５】
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）、チタン酸ストロンチウム、炭酸カルシウム、炭酸マグウネシウム、炭酸カルシウム、炭酸マグウネシウム、酸化アルミニウム、酸化セリウム、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。
【００６６】
有機樹脂微粒子としては、フッ素含有樹脂微粒子、シリカ含有樹脂微粒子及び窒素含有樹脂微粒子等が好ましい。
【００６７】
また必要に応じて前記無機粉末表面の疎水性、帯電特性等を改質する目的で、表面処理剤として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なども提案されているが、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。
【００６８】
また、外部添加剤としては、大粒径と小粒径の２種以上の粒径が異なるもので構成されるものが好ましい。
大粒径と小粒径の２種以上の異なる粒径のもので構成される外部添加剤は、大粒径外部添加剤がスペーサーの役割を果たし、トナー流動性に効果がある小粒径外部添加剤のトナー母体への埋没が防止され、トナー流動性を維持でき、経時での外部添加剤のトナー母体への埋没が急激に進み、トナー流動性の悪化が急激に進み、トナーの流動性が低下することによる画像むらの発生や画像ぬけを防止できる。
【００６９】
大粒径のものとしては、ＢＥＴ比表面積が５０ｍ²／ｇ以下、特に、３０〜５０ｍ²／ｇのものがより好ましい。５０ｍ²／ｇ以下の範囲にあれば、種々の表面処理されたものが使用可能であり、また、３０ｍ²／ｇ未満の場合はトナーの流動性が急激に低下することによる画像むらが発生しやすく、また、トナーへの付着力が強くなり難く、トナーからの脱離が容易に起こり、感材傷、画像ぬけの原因となる。
【００７０】
これら大きな粒径の外部添加剤は、トナー１００重量部に対して０．５〜３．０重量部の範囲で添加するのが好ましく、１．０〜１．８重量部の範囲で添加するのがより好ましい。１．０重量部未満の場合は転写不良が発生し、また、原因は不明ではあるが、経時での現像担持体の薄層形成が不均一となる。３．０重量部を超える場合ではトナーからの脱離が容易に起こり、感材傷、画像ぬけの原因となる。
【００７１】
小粒径のものとしては、ＢＥＴ比表面積が１１０ｍ²／ｇ以上の範囲にあれば、種々の表面処理されたものが使用可能であるので好ましい。特に、１１０〜１７０ｍ²／ｇのものが、特に、トナーの付着力を低減するため効果があるのでより好ましい。
【００７２】
これらの外部添加剤は、トナー１００重量部に対して０．３〜３重量部の範囲で添加するのが好ましく、０．５〜１．５重量部の範囲で添加するのがより好ましい。０．３重量部未満の場合は、その効果が十分に発揮されにくく、３重量部を超えると、トナーから脱離する外部添加剤が多くなり、感光体傷等を引き起こすし易くなる。
【００７３】
特に、粒径の異なるシリカ微粒子を含有することが好ましく、ＢＥＴ比表面積が１１０ｍ²／ｇ以上の疎水性シリカ粒子とＢＥＴ比表面積が５０ｍ²／ｇ以下の疎水性シリカ粒子を組み合わせたものがトナー流動性が向上するのでより好ましい。
【００７４】
また、本発明においては、酸化チタン粒子の少なくとも一つにおいて、形成されるアルミニウム又はアルミナ被膜は、Ａｌ₂Ｏ₃換算で０．１〜２．０重量％の範囲であることが好ましい。Ａｌ₂Ｏ₃換算０．１重量％未満の場合は、その効果が弱められ、Ａｌ₂Ｏ₃換算２．０重量％を超える場合には、アルミニウムの＋帯電性が機能し、負極性トナーの帯電性を低下させてしまう。
【００７５】
また、上記アルミニウム又はアルミナ被膜が形成された酸化チタン微粒子の少なくとも一種の粒子表面は、更に処理剤として、アニオン界面活性剤、両性イオン界面活性剤、シランカップリング剤、シリコーンオイル、脂肪酸、脂肪酸エステルの少なくともいずれか一種の化合物で表面処理されることが好ましい。それにより酸化チタン微粒子における表面処理剤の剥がれが長期ストレス下においても発生せず、安定な負帯電性能を得ることができる。
【００７６】
本発明において、酸化チタン微粒子にアルミニウム又はアルミナ被膜を形成することにより、処理剤の剥がれが抑制されるメカニズムは明確ではないが、次のように推測される。酸化チタン微粒子表面に、まずアルミニウム又はアルミナ被膜を形成すると、アルミナの等電点が比較的高いため中性付近で表面電荷は＋になっている。その状態のものに、アニオン界面活性剤、両性イオン界面活性剤、シランカップリング剤、シリコーンオイル、脂肪酸、脂肪酸エステルの少なくともいずれか一種の化合物を加えると、それらの化合物が配向吸着されて酸化チタン微粒子表面が親油化する。更に熱を加えることにより結合等はより強いものとなり、表面処理剤の剥がれが抑制されるものと推測される。
【００７７】
（トナーの製造方法）
本発明の製造方法は、少なくとも結着剤樹脂、主帯電制御剤及び顔料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トナーの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。
【００７８】
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のが好ましい。
【００７９】
少なくとも結着剤樹脂、主帯電制御剤及び顔料、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などを用いて通常の条件で行えばよく、特に制限はない。
【００８０】
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、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２軸押出機、東芝機械社製ＴＥＭ型押出機、ケイ・シー・ケイ社製２軸押出機、池貝鉄工所社製ＰＣＭ型２軸押出機、ブス社製コニーダー等が好適に用いられる。
【００８１】
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。
【００８２】
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。
【００８３】
この粉砕工程が終了した後に、粉砕物を遠心力などで気流中で分級し、もって所定の粒径例えば平均粒径が５〜２０μｍの現像剤を製造する。
【００８４】
また、現像剤を調製する際には、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現像剤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。
【００８５】
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、温度など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良いし、その逆でも良い。
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などが挙げられる。
【００８６】
（フルカラー画像現像方法）
本発明における導電性ブラシを用いた非磁性一成分現像方式において特定の円形度を持つ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において特にハーフトーンの均一再現性にその効果を有効に利用できる。
【００８７】
本発明の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。
【００８８】
また、本発明の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の現像装置によって、それぞれの色に対応した複数の感光体上に、各色に分割された静電潜像を導電性ブラシ帯電器及び露光装置によって形成し、対応する色の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。
【００８９】
【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、以下の例おいて、部及び％は、特に断りのない限り重量基準である。
【００９０】
（帯電制御樹脂の合成例）
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１．１重量％、重量平均分子量２５０００、見掛け粘度が１０⁴Ｐ（１０⁴Ｐ＝１０⁴ｇ／ｃｍ・ｓ）となる温度が９６℃の帯電制御樹脂Ａを得た。
【００９１】
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３．６重量％、重量平均分子量５３００、見掛け粘度が１０⁴Ｐ（１０⁴Ｐ＝１０⁴ｇ／ｃｍ・ｓ）となる温度が８５℃の帯電制御樹脂Ｂを得た。
【００９２】
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％、重量平均分子量９８０００、見掛け粘度が１０⁴Ｐ（１０⁴Ｐ＝１０⁴ｇ／ｃｍ・ｓ）となる温度が１１０℃の帯電制御樹脂Ｃを得た。
【００９３】
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％、重量平均分子量５００００、見掛け粘度が１０⁴Ｐ（１０⁴Ｐ＝１０⁴ｇ／ｃｍ・ｓ）となる温度が１０５℃の帯電制御樹脂Ｄを得た。
【００９４】
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％、重量平均分子量３００００、見掛け粘度が１０⁴Ｐ（１０⁴Ｐ＝１０⁴ｇ／ｃｍ・ｓ）となる温度が１０１℃の帯電制御樹脂Ｅを得た。
【００９５】
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％、重量平均分子量１１５０００、見掛け粘度が１０⁴Ｐ（１０⁴Ｐ＝１０⁴ｇ／ｃｍ・ｓ）となる温度が１１０℃の帯電制御樹脂Ｆを得た。
【００９６】
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５．１重量％、重量平均分子量２８００、見掛け粘度が１０⁴Ｐ（１０⁴Ｐ＝１０⁴ｇ／ｃｍ・ｓ）となる温度が８０℃の帯電制御樹脂Ｇを得た。
【００９７】
（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）。
【００９８】
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７１２２５ｇ、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）。
【００９９】
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）。
【０１００】
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）。
【０１０１】
（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）。
【０１０２】
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）。
【０１０３】
（トナー製造例１）
水 ６００部
Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ １８０
含水ケーキ（固形分５０％） １２００部
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。
【０１０４】
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 １．５部
上記材料をミキサーで混合後、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６．０μｍ、体積平均径７．１μｍ（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。
【０１０５】
（外添剤との混合と得られたトナーの評価）
得られた４色の着色粒子１００重量部と外添剤として、疎水性シリカＡ（ワッカー社ＨＤＫ Ｈ２０００）１．０重量部、疎水性シリカＣ（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Ｅ（テイカ社 ＭＴ−１５０ＡＩ）０．５重量部を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事により電子写真用トナーＴ１を得た。
表１に使用した外添剤、表２に結着樹脂及び帯電制御剤の組み合わせと得られたトナーを示す。
【０１０６】
（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）にて実施した。
【０１０７】
（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。
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。これを各色単独に５点測定し各色ごとに平均を求めた。
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。
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。○は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。
【０１０８】
４）物性測定
４−１）〔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ＴＡＩII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。
４−２）〔帯電量〕
（帯電量）本発明におけるトナーの帯電量は、トナーとキャリアを混合させて現像剤としたときの帯電量を示す。このときの現像剤中のトナー濃度（ＴＣ）は３〜５重量％とする。ＴＣは以下のようにして求められる。
ＴＣ（重量％）＝
（トナー重量）／［（トナー重量）＋（キャリア重量）］×１００
トナー及びキャリアを調製した現像剤６ｇを、直径２．５ｃｍ、高さ３．０ｃｍの円筒状のステンレス瓶に入れ、ボールミルで２５０ｒｐｍの速度で所定時間撹拌してそのときのトナーの帯電量をブローオフ法で測定する。（キャリアにはパウダーテック社 ＦＰＣ−３００を使用）
実験機の場合；現像ローラ（スリーブ）上にトナーを搬送させ、吸引トリボ測定法にて測定した。
【０１０９】
５）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（株）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。
６）透明性
９０ｍｍ／ｓｅｃ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（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％以上のものを×と評価した。
７）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
【０１１０】
その他トナー製造例を表２にまとめた。トナー粒径、帯電制御樹脂及びその添加量、結着樹脂以外は、実施例１と同様にトナーを調製した。また、実施例及び比較例の実機評価の結果を表３にまとめた。
【０１１１】
下記表１に使用外添剤を示す。
【表１】

【０１１２】
下記表２にトナー処方を示す。
【表２】

【０１１３】
下記表３に実機評価結果を示す。
【表３】

【０１１４】
【発明の効果】
本発明によれば、一成分カラー現像方式のいずれの方式においても、従来のものに比し、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イエロートナーが得られる。
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などの問題がなく、発色性、色再現性の良い画像が得られる。このように長期の耐久性があるため、現像ユニット、感光体ユニットなどの長寿命化が達成でき、使用後発生するリサイクル物、廃棄物が従来のものより少なく、ユーザーの作像ユニット交換の手間が少なくすることが可能になる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner used as a developer for developing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing, etc., a container containing the toner, and electrophotographic development using the toner The present invention relates to an apparatus and an image forming method.
More specifically, an external additive for electrophotographic toner, an electrophotographic toner, an electrophotographic developer, and an electrophotographic developer used in a copying machine, a laser printer, and a plain paper fax machine using a direct or indirect electrophotographic developing system. Relates to the device.
Further, the present invention relates to a full-color copying machine, a full-color laser printer, a full-color plain paper fax machine, and the like that use a direct or indirect electrophotographic multicolor image developing system, an electrophotographic toner, an electrophotographic developer, and an electrophotographic developing apparatus.
[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, 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 toners are known. In the two-component development method, the developer deteriorates due to the toner particles adhering to the carrier surface, and the toner concentration in the developer decreases because only the toner is consumed, so the mixing ratio with the carrier is constant. Therefore, there is a disadvantage that the developing device becomes large. On the other hand, the one-component development method is becoming the mainstream of the development method because it does not have the above disadvantages and the apparatus has advantages such as downsizing.
[0003]
In recent years, office automation and colorization have further progressed in offices. In addition to copying originals consisting only of conventional characters, originals including graphs created with a personal computer are output by a printer and used as presentation materials. Opportunities to copy many sheets are 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.
[0004]
Conventionally, electrophotographic processes using a one-component developer are classified into a magnetic one-component developing method using a magnetic toner and a non-magnetic one-component developing method using a non-magnetic toner. In the magnetic one-component development method, a developer carrying member provided with a magnetic field generating means such as a magnet is used to hold magnetic toner containing a magnetic material such as magnetite, and the layer thickness is regulated by a layer thickness regulating member. In recent years, a large number of small printers have been put to practical use. On the other hand, in the non-magnetic one-component development method, since the toner does not have a magnetic force, the toner replenishing roller or the like is pressed against the developer carrying member, and the toner is supplied onto the developer carrying member and held electrostatically. Because it is developed with a thin layer by a layer thickness regulating member, it has the advantage that it can be colorized because it does not contain a colored magnetic material, and it does not use a magnet for the developer carrier, so it is lighter Cost reduction is possible, and in recent years it has begun to be put into practical use in small full-color printers and the like.
[0005]
However, in the one-component development system, there are still many problems to be improved. In the two-component development method, a carrier is used as a means for charging and transporting the toner, and the toner and the carrier are sufficiently stirred and mixed inside the developing device and then transported to the developer carrier for development. In this case, stable charging and conveyance can be continued, and it is easy to cope with a high-speed developing device.
[0006]
Compared to this, the one-component development method does not have a stable charging / conveying means such as a carrier, and therefore, 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 friction charging between the toner and the developer carrier, the layer thickness regulating member, etc. Since the contact / friction charging time with the member is very short, the amount of low-charged and reverse-charged toner tends to increase more than the two-component development 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 diameter is used. In particular, a one-component developer having a high electric resistance is used as the toner. In this case, since the toner needs to be charged by the developing device, the layer thickness of the toner must be remarkably 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 faster charging speed and an appropriate charge amount.
[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.
Typical negative charge control agents include monoazo dyes, salicylic acid, naphthoic acid, dicarboxylic acid metal salts / metal complex salts, diazo compounds, boron complex compounds, and the like. Examples of the control agent include quaternary ammonium salt compounds, imidazole compounds, nigrosine, and azine dyes. 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 compatible with the binder resin, what is present on the surface of the toner, which is greatly involved in charging, is likely to be detached. There are drawbacks such as body filming that are easily contaminated. Therefore, in the past, a good image was obtained in the initial stage, but the image quality gradually changed, resulting in the phenomenon of background smudges and blurring. Especially, it was applied to color copying and used continuously while replenishing toner. Then, the charge amount of the toner decreases, resulting in an image that differs significantly from the color tone of the initial copy image, and it is not possible to withstand long-term use. It had disadvantages that had to be done. For this reason, the load on the environment is large, and it takes time and effort for the user. Furthermore, since many of these contain heavy metals such as chromium, they are becoming a problem from the viewpoint of safety in recent years.
[0008]
Therefore, in order to improve the above problem, in JP-A-63-88564, JP-A-63-184762, JP-A-3-56974, and JP-A-6-230609, a phase to a binder resin is disclosed. A resin charge control agent having improved solubility, transparency of a toner fixed image, and safety is disclosed. Since these resin charge control agents have good compatibility with the binder resin, they are excellent in stable chargeability and transparency. However, these resin charge control agents have the disadvantage that the charge amount and charging speed are inferior compared with toners using metal salts and metal complex salts of monoazo dyes, salicylic acid, naphthoic acid and 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.
[0009]
Therefore, 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 electron withdrawing are disclosed. Copolymers with aromatic monomers having groups 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 0.5 to 2.0% by weight by the devolatilization step, but the resin negative charge control of the present invention. The agent retains more water and polymerization solvent, which may be attributed to monomers containing organic acid salts such as sulfonate groups, and the volatile content increases. Therefore, there is a problem in handling such as a problem in storage stability of the resin negative charge control agent itself, or agglomeration if the material is allowed to stand after premixing before kneading and 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 photoreceptor 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.
[0010]
Further, in order to improve the compatibility with the styrene resin or polyester resin as the 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, respectively. Copolymers with styrenic monomers for styrenic resins and polyester monomers for binder resins when used as binder resins have also been proposed. The anti-ming effect 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.
[0011]
In recent years, the demand for printers has expanded, the size and speed of devices have increased, and the cost has been reduced. As a result, higher reliability and longer life have been required for devices, and toner characteristics can be maintained over a long period of time. However, these resin charge control agents cannot maintain the charge control effect, contaminate the developing sleeve and the layer thickness regulating member (blade or roller), and decrease the toner charging performance, There was a problem to do.
[0012]
[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 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 the chargeability of toner 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, and an image forming method capable of obtaining tens of thousands or more of image quality.
Another object of the present invention is to provide electrophotographic toner, developer, and image that prevent contamination of developing sleeves and layer thickness regulating members (blades and rollers) and photoconductor filming over tens of thousands of sheets in long-term use. A forming method is provided.
Furthermore, another object of the present invention is to provide an electrophotographic toner, a developer, and an image forming method with less toner scattering in a developing machine even in long-term use.
Another object of the present invention is to provide an electrophotographic toner, a developer, and an image forming method 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. It is to provide.
Another object of the present invention is to provide an electrophotographic toner having good color reproducibility by using a colorless or light resin charge control agent.
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.
[0013]
[Means for Solving the Problems]
In order to solve such problems, the present inventors have paid attention to the constituent components and the constituent ratio of the resin charge control agent and, as a result of intensive studies, have found that the polyester resin is suitable as a binder resin for full-color toners in terms of color developability and image strength. When a resin charge control agent having a specific component and composition ratio is used for a polyol resin or a polyol resin, a high charge amount and a sharp charge distribution can be obtained. Obtaining the knowledge that electrophotographic toner, developer, and image forming method that can prevent contamination of the regulating member (blade and roller) and photoconductor filming, and have good grindability and high productivity can be obtained. Was able to reach.
[0014]
That is, the present invention can solve the above problems by employing the following technical means.
The first aspect of the present invention is a yellow toner used for full color image formation for reproducing a multicolor image.
(A) a binder resin having an acid value of 20 KOHmg / g or less,
(B) C.I. I. A compound classified as Pigment Yellow 180,
(C) At least one selected from the group consisting of a sulfonate group-containing monomer (1), an aromatic monomer (2) having an electron withdrawing group, an acrylate monomer, a methacrylic acid ester monomer, and an aromatic vinyl monomer (3 ) And a resin negative charge control agent having a volatile content of 5% or less.
[0015]
A second aspect of the present invention is the yellow toner according to claim 1, wherein the charging characteristics of the untreated toner additive satisfy the following formula (a).
A / B ≧ 0.8 (a)
[A: Unsaturated charge amount B: Saturated charge amount]
[0016]
According to a third aspect of the present invention, in the first or second aspect, the dispersion particle diameter of the resin negative charge control agent is 0.05 to 1.50 μm in the major axis and 0.02 to 1.00 μm in the minor axis. In electrophotographic toner.
[0017]
According to a fourth aspect of the present invention, the repeating unit of the sulfonic acid group-containing monomer is 1 to 30% by weight based on the weight of the resin negative charge control agent, and the repeating unit of the aromatic monomer having the electron withdrawing group is a resin negative charge control. 1 to 80% by weight with respect to the weight of the agent, 10 to 80% by weight of the repeating unit of the acrylate monomer and / or methacrylic acid ester monomer with respect to the weight of the resin negative charge control agent, and the repeating unit of the aromatic vinyl monomer Is contained in a ratio of 0 to 30% by weight based on the weight of the resin negative charge control agent.
[0018]
A fifth aspect of the present invention is the first to the fourth aspect, 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 toner for electrophotography.
[0019]
In the sixth aspect of the present invention, the apparent viscosity of the resin negative charge control agent by a flow tester is 10 ^Four P (10 ^Four P = 10 ^Four g / cm · s), wherein the first to fifth electrophotographic toners are 85 to 110 ° C.
[0020]
A seventh aspect of the present invention resides in the first to sixth electrophotographic toners, wherein the resin negative charge control agent has a weight average molecular weight of 5,000 to 100,000.
[0021]
According to an eighth aspect of the present invention, in the first to seventh electrophotographic toners, the resin negative charge control agent is contained in an amount of 0.1 to 2% by weight based on toner particles.
[0022]
In the ninth aspect of the present invention, the toner particles have a BET specific surface area of 110 m. ² / G of hydrophobic silica particles and BET specific surface area of 50m ² / G or less hydrophobic silica particles are added, and titanium oxide particles are added.
[0023]
According to a tenth aspect of the present invention, the relationship between the number average particle diameter and the volume average particle diameter of the toner particles is volume average particle diameter (Dv) / number average particle diameter (Dn) ≦ 1.4. The first to ninth electrostatic charge image developing toners.
[0024]
The eleventh aspect of the present invention resides in a container that contains the first to tenth toners.
[0025]
A twelfth aspect of the present invention is an image forming apparatus having the eleventh container mounted thereon.
[0026]
According to a thirteenth aspect of 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 a developed toner image And a fixing step for heating and fixing a toner image on the transfer body, and the first to tenth toners are used as a developer. In the image forming method.
[0027]
According to a fourteenth aspect of the present invention, in the developing step, a thin layer of a developer is formed on a developer carrying member, and the developing is performed in contact or non-contact with the latent image holding member. Is in the way.
[0028]
According to a fifteenth aspect of the present invention, in the latent image forming step, the latent image formed is an electrostatic latent image divided into multiple colors, and a plurality of latent images corresponding to the colors of the electrostatic latent image, respectively. A plurality of developers each corresponding to a color of an electrostatic latent image, and each of the plurality of developers corresponding to the plurality of developers in the developing step; The electrostatic latent image is developed using a plurality of multicolor developing devices including a developing roll and a developing blade that uniformly regulates the layer thickness of the developer supplied onto the developing roll. 15. The image forming method according to the thirteenth or fourteenth aspect, wherein a transfer member is brought into contact with the surfaces of a plurality of latent image holding members developed in a developing step, and the developed toner images are sequentially electrostatically transferred to the transfer member. It is in.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
In the present invention, the binder resin is polyester and / or polyol, and the charge control agent is at least a sulfonate group-containing monomer as a monomer, an aromatic monomer having an electron withdrawing group, an acrylate ester, and / or a methacrylate ester. An electrophotographic toner which is a resin charge control agent having a monomer as a structural unit.
[0030]
Examples of the sulfonate group-containing monomer constituting the resin charge control agent of the present invention include aromatic sulfonate group-containing monomers and aliphatic sulfonate group-containing monomers.
[0031]
Examples of the aromatic sulfonate group-containing monomer include alkali metal salts such as vinyl sulfonic acid, allyl vinyl sulfonic acid, 2-acrylamido-2 methylpropane sulfonic acid, methacryloyloxyethyl sulfonic acid, alkaline earth metal salts, amine salts, and 4 Class ammonium salt etc. are mentioned.
[0032]
Examples of the aliphatic sulfonate group-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.
[0033]
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, nitrophenyl ( Phenyl (meth) acrylate substitution products such as meth) acrylate and chlorophenyloxyethyl (meth) acrylate, phenyl (meth) acrylamide substitution products such as chlorophenyl (meth) acrylamide, bromophenyl (meth) acrylamide, and nitrophenyl (meth) acrylamide, Substituted phenylmaleimide such as chlorophenylmaleimide, dichlorophenylmaleimide, nitrophenylmaleimide, nitrochlorophenylmaleimide, chlorophenylitame N'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 nitrophenyl 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.
[0034]
As acrylic ester and / or methacrylic ester monomers, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate , Stearyl (meth) acrylate, dodecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and the like.
[0035]
Examples of the aromatic vinyl monomer include styrene, vinyl toluene, α-methyl styrene and the like.
[0036]
By adding a sulfonate group-containing monomer as a monomer constituting the resin charge control agent of the present invention, the negative charge imparting effect of the resin charge control agent is improved. However, because of the hygroscopic property, the environmental stability of the toner (temperature and humidity) It is generally known to be used as a copolymer with an aromatic monomer having an electron-withdrawing group or the like, but it may be used in the order of several thousand sheets, but it has a length of tens of thousands or more. When used for a long period of time, contamination of the developing sleeve and the layer thickness regulating member (blade and roller) and photoconductor filming occur, and the charging stability of the toner and the maintenance of high image quality are not sufficient, and the productivity also decreases. There is a problem. In order to compensate for these disadvantages, aromatic monomers and acrylate esters having a sulfonate group-containing monomer and an electron-withdrawing group compared to polyester resins and polyol resins that are suitable as a binder resin for full-color toners in terms of color developability and image strength. And / or by using a copolymer containing three types of methacrylic acid ester monomers as a resin charge control agent, it is excellent in charging and environmental stability over a long period of time, and has a developing sleeve and a layer thickness regulating member (blade or No contamination of the roller), the formation of a thin layer is good, the photoconductor filming is prevented, the high image quality is maintained, and the electrophotographic toner with high productivity can be obtained.
[0037]
These effects are presumed to be as follows. That is, the combined use of a sulfonate group-containing monomer and an aromatic monomer having an electron-withdrawing group enhances the effect of imparting negative charge, and the use of acrylic acid ester and / or methacrylic acid ester monomer further stabilizes the charging environment. In addition, the resin hardness is increased, the grindability is improved, the developing sleeve and the layer thickness regulating member (blade and roller) are not contaminated, and the effect of preventing photoconductor filming is improved. By combining with a suitable polyester resin or polyol resin from the viewpoint of color developability and image strength as a resin, it is possible to obtain an electrophotographic toner with appropriate dispersibility and a sharp charge distribution.
[0038]
The composition ratio of the monomers in the resin charge control agent of the present invention is 1 to 30% by weight of the sulfonic acid group-containing monomer, more preferably 2 to 20% by weight. When the sulfonic acid group-containing monomer is less than 1% by weight, the rising of the charge and the charge amount are not sufficient, and the image tends to be affected. On the other hand, if it exceeds 30% by weight, the environmental stability of charging is deteriorated, the charge amount at high temperature and high humidity is low, the charge amount at low temperature and low humidity is high, and the toner charge stability and high image quality are not sufficiently maintained. Further, there is a problem that the developing sleeve and the layer thickness regulating member (blade or roller) are easily contaminated and the photosensitive member filming occurs, and the productivity at the time of toner production by the kneading / pulverizing method is lowered.
[0039]
The aromatic monomer having an electron withdrawing group is 1 to 80% by weight, more preferably 20 to 70% by weight. When the amount of the aromatic monomer having an electron-withdrawing group 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 toner scattering are likely to occur, and the high image quality cannot be maintained sufficiently.
[0040]
Acrylic acid ester and / or methacrylic acid ester monomer content is 10 to 80% by weight, more preferably 20 to 70% by weight. When the acrylate and / or methacrylic acid ester monomer is less than 10% by weight, sufficient charging environmental stability cannot be obtained, and the pulverizability at the time of toner production by the kneading / pulverization method is not sufficient. Further, contamination of the developing sleeve and the layer thickness regulating member (blade or roller) and photoconductor filming cannot be sufficiently prevented. If it exceeds 80% by weight, the rise of charge and the amount of charge are not sufficient, and the image tends to be affected.
[0041]
The aromatic vinyl monomer is 0 to 30% by weight, more preferably 3 to 20% by weight. 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 becomes wide, and the toner is likely to be smeared or scattered in the machine. Further, the toner fixability, particularly the color developability when color toners are mixed, becomes poor.
[0042]
These resin charge control agents can be combined with a polyester resin or polyol resin that is suitable as a binder resin for full-color toners in terms of color developability and image strength, thereby providing appropriate dispersibility and sharp charge distribution. Electrophotographic toner can be obtained, and long-term charging stability and high image quality can be obtained.
[0043]
The apparent viscosity by the flow tester of the resin charge control agent of the present invention is 10 ^Four P (10 ^Four P = 10 ^Four g / 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. When the temperature exceeds 110 ° C., the 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 10 ^Four P (10 ^Four P = 10 ^Four g / cm · s), the viscosity was measured using a flow tester with a load of 10 kg / cm 2, an orifice of 1 mm × 1 mm, and a heating rate of 5 ° C./min. ^Four P (10 ^Four P = 10 ^Four g / cm · s). Shimadzu Corporation CFT-500 type can be used as a flow tester.
[0044]
The number average molecular weight of the resin charge control agent of the present invention is preferably 5,000 to 100,000. If it is less than 5,000, moderate dispersibility in the toner cannot be obtained, charging is not only reduced, but in the method obtained from the production process of kneading, pulverization and classification, sticking in the pulverization process is likely to occur. Deteriorate productivity. On the other hand, if it exceeds 100,000, the dispersibility in the toner is lowered, the charge distribution is widened, the soiling and the toner scattering in the machine are liable to occur, and the toner fixing property and color developing property become poor.
[0045]
The dispersion 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.
[0046]
The addition amount of the resin charge control agent of the present invention is preferably 0.1 to 2% by weight, more preferably 0.5 to 1.5% by weight, based on the toner particles. When the amount is less than 0.1% by weight, the charge holding ability and the charge amount with time are not sufficient, and the image is easily affected. When it exceeds 2% by weight, an increase in charge with time occurs, and a decrease in image density tends to occur. Furthermore, charging aggregation between toner particles due to increased charge occurs, resulting in poor thin layer formation. Further, 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 alkylsalicylic acid may be used in combination.
[0047]
As the binder resin used in the present invention, a polyester resin or a polyol resin that is suitable as a binder resin for full-color toners from the viewpoint of color developability and image strength is 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.
[0048]
The polyester resin can be generally obtained by an esterification reaction of a polyhydric alcohol and a polycarboxylic acid.
[0049]
Among the monomers constituting the polyester resin in the present invention, examples of alcohol monomers include trifunctional or higher polyfunctional monomers such as ethylene glycol, diethylene glycol triethylene glycol, 1,2-propylene glycol, and 1,3-propylene. Diols such as 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, trimethylolethane , Trimethylolpropane, 1,3,5-trihydroxybenzene, and other trihydric or higher polyhydric alcohols.
[0050]
Among these monomers, 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.
[0051]
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. , Terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, alkenyl succinic acid such as n-dodecenyl succinic acid, n-dodecyl succinic acid or alkyl succinic acid, anhydrides of these acids 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- 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, empor trimer acid, and These anhydrides, alkyl esters, alkenyl esters, aryl esters, and other trivalent or higher carboxylic acids can be mentioned.
[0052]
Specific examples of the alkyl group, alkenyl group or aryl ester described here include 1,2,4-benzenetricarboxylic acid, trimethyl 1,2,4-benzenetricarboxylate, and triethyl 1,2,4-benzenetricarboxylate. 1,2,4-benzenetricarboxylic acid tri-n-butyl, 1,2,4-benzenetricarboxylic acid isobutyl, 1,2,4-benzenetricarboxylic acid tri-n-octyl, 1,2,4-benzenetricarboxylic acid tri 2-ethylhexyl, 1,2,4-benzenetricarboxylic acid tribenzyl, 1,2,4-benzenetricarboxylic acid tris (4-isopropylbenzyl) and the like.
[0053]
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. . Accordingly, the acid value of the polyester resin is preferably 20 KOHmg / g or less, and more preferably 5 KOHmg / g or less.
[0054]
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.
[0055]
Examples of the alkylene oxide adduct of the dihydric phenol having both glycidyl groups used in the present invention include the following.
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.
[0056]
[Chemical 1]

(Here, R represents an alkylene group represented by the following chemical formula 2. Also, n and m are the number of repeating units, each of 1 or more and n + m = 2 to 6.)
[0057]
[Chemical formula 2]

[0058]
In the toner of the present invention, the toner particles have a volume average particle diameter of 4 to 9 μm, and the ratio of the volume average diameter Dv to the number average diameter Dn is Dv / Dn ≦ 1.4. Less. When Dv / Dn> 1.4, toner filming on the developing roller and the thin layer forming member is likely to occur. In addition, the toner particle size distribution fluctuates over time, the charge amount fluctuates, and the image density fluctuates. Further, Dv / Dn is preferably 1.1 or more.
[0059]
C. as a colorant I. The amount of the compound classified as Pigment Yellow 180 is generally 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The colorant also has a charge generation effect, and even a toner without a charge control agent generates a charge amount equivalent to that of a toner with a charge control agent added. However, if a charge control agent is not added, the charge retention ability over time will decrease. Moreover, it is preferable that the upper limit of A / B is 1.2.
[0060]
It is preferable that the charging characteristics of the untreated toner additive satisfy the following formula (a). In the case of A / B <0.8, the image density decreases due to the increase in toner charge over time, and further, the toner thin layer formation amount on the developer carrying member becomes excessive due to the increase in charge, resulting in background stains. End up.
A / B ≧ 0.8 (a)
[A: Unsaturated charge amount B: Saturated charge amount]
Here, A: Unsaturated charge amount indicates the toner charge amount in the minimum stirring time during which TC at the time of blow-off measurement is stabilized by the method for measuring the charge amount of toner shown in the following examples, and B: The saturation charge amount indicates the charge amount of the toner when the charge amount when the stirring time is extended by the method for measuring the charge amount of the toner reaches saturation.
[0061]
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 low temperature may be insufficient. On the other hand, when the melting point is excessively low, the offset resistance and durability may be deteriorated. The melting point of the wax is determined by a 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.
[0062]
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. And 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.
[0063]
Examples of the cleaning property improver for removing the developer after transfer remaining on the photoreceptor or the primary transfer medium include, for example, zinc stearate, calcium stearate, fatty acid metal salts such as stearic acid, such as polymethyl methacrylate fine particles, polystyrene fine particles, etc. And polymer fine particles produced by soap-free emulsion polymerization. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.
[0064]
As the external additive of the present invention, known external additives such as inorganic fine particles and organic fine particles can be used. Among them, toner particles and various metal oxides are used for the purpose of improving the flow characteristics and charging characteristics of the toner. A method of mixing and using inorganic powders such as products has been proposed and is called an external additive.
[0065]
Examples of the inorganic powder include silicon dioxide (silica), titanium dioxide (titania), strontium titanate, calcium carbonate, magnesium carbonate, calcium carbonate, magnesium carbonate, aluminum oxide, cerium oxide, zinc oxide, magnesium oxide, and cerium oxide. Iron oxide, copper oxide, tin oxide and the like are known.
[0066]
As the organic resin fine particles, fluorine-containing resin fine particles, silica-containing resin fine particles, nitrogen-containing resin fine particles and the like are preferable.
[0067]
In addition, for the purpose of modifying the hydrophobicity, charging characteristics, etc. of the surface of the inorganic powder as required, a method of treating with a specific silane coupling agent, titanate coupling agent, silicone oil, organic acid, etc. as a surface treatment agent, A method of coating a specific resin has also been proposed. In particular, silica and titanium oxide fine particles are reacted with organosilicon compounds such as dimethyldichlorosilane, hexamethyldisilazane, and silicone oil to form silanol groups on the surface of the silica fine particles. Silica fine particles substituted with groups and hydrophobized are used.
[0068]
Moreover, as an external additive, what is comprised by the thing from which 2 or more types of particle sizes with a large particle size and a small particle size differ is preferable.
External additives composed of two or more different particle sizes, large particle size and small particle size, have a large particle size external additive that acts as a spacer and has an effect on toner fluidity. The embedment of the additive in the toner base is prevented, the toner fluidity can be maintained, the embedment of the external additive in the toner base over time progresses rapidly, the toner fluidity deteriorates rapidly, and the toner fluidity It is possible to prevent the occurrence of image unevenness and image omission due to a decrease in image quality.
[0069]
For large particle size, BET specific surface area is 50m ² / G or less, especially 30-50 m ² / G is more preferable. 50m ² / G or less, various surface-treated ones can be used, and 30 m ² / G is less likely to cause image unevenness due to a sharp drop in the fluidity of the toner, and the adhesion to the toner is unlikely to be strong, and the release from the toner easily occurs, It may cause image loss.
[0070]
These external additives having a large particle diameter are preferably added in the range of 0.5 to 3.0 parts by weight, and in the range of 1.0 to 1.8 parts by weight, based on 100 parts by weight of the toner. Is more preferable. When the amount is less than 1.0 part by weight, transfer failure occurs, and although the cause is unknown, the formation of a thin layer of the developing carrier over time becomes uneven. When the amount exceeds 3.0 parts by weight, detachment from the toner occurs easily, which may cause a photosensitive material scratch and image blur.
[0071]
For small particle size, BET specific surface area is 110m ² If it is in the range of not less than / g, various surface-treated ones can be used. Especially 110-170m ² / G is particularly preferable because it is effective for reducing the adhesion force of the toner.
[0072]
These external additives are preferably added in the range of 0.3 to 3 parts by weight and more preferably in the range of 0.5 to 1.5 parts by weight with respect to 100 parts by weight of the toner. When the amount is less than 0.3 part by weight, the effect is not sufficiently exerted, and when the amount exceeds 3 parts by weight, the amount of the external additive that is detached from the toner increases, and the photosensitive member is likely to be damaged.
[0073]
In particular, silica fine particles having different particle diameters are preferably contained, and the BET specific surface area is 110 m. ² / G of hydrophobic silica particles and BET specific surface area of 50m ² / G or less of hydrophobic silica particles are more preferable because the toner fluidity is improved.
[0074]
In the present invention, the aluminum or alumina coating formed on at least one of the titanium oxide particles is Al. ₂ O _Three It is preferably in the range of 0.1 to 2.0% by weight in terms of conversion. Al ₂ O _Three When the conversion is less than 0.1% by weight, the effect is weakened and Al ₂ O _Three When the conversion exceeds 2.0% by weight, the positive chargeability of aluminum functions and the chargeability of the negative polarity toner is lowered.
[0075]
In addition, the surface of at least one kind of titanium oxide fine particles on which the aluminum or alumina coating is formed is further treated with an anionic surfactant, a zwitterionic surfactant, a silane coupling agent, a silicone oil, a fatty acid, and a fatty acid ester. It is preferable that the surface treatment is performed with at least one kind of compound. Thereby, peeling of the surface treatment agent in the titanium oxide fine particles does not occur even under long-term stress, and stable negative charging performance can be obtained.
[0076]
In the present invention, the mechanism by which the treatment agent is prevented from being peeled off by forming an aluminum or alumina coating on the titanium oxide fine particles is not clear, but is presumed as follows. When an aluminum or alumina film is first formed on the surface of the titanium oxide fine particles, the surface charge is + near neutrality because the isoelectric point of alumina is relatively high. When an anionic surfactant, a zwitterionic surfactant, a silane coupling agent, a silicone oil, a fatty acid, or a fatty acid ester is added to the compound in that state, the compound is oriented and adsorbed to form titanium oxide. The fine particle surface becomes lipophilic. Further, by applying heat, the bonding and the like become stronger, and it is estimated that peeling of the surface treatment agent is suppressed.
[0077]
(Toner production method)
The production method of the present invention includes a step of mechanically mixing developer components including at least a binder resin, a main charge control agent, and a pigment, a step of melt-kneading, a step of pulverizing, and a step of classifying. A toner manufacturing method can be applied. In addition, in the mechanical mixing step and the melt-kneading step, a production method is also included in which powder other than the particles that become the product obtained in the pulverization or classification step is returned and reused.
[0078]
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 generated as products having a desired particle diameter. It is preferable that such a by-product is mixed in the weight ratio of the other raw material 50 to the sub-product 50 from the other raw material 99 to the sub-product 1 in the mixing step and the melt-kneading step.
[0079]
The mixing step of mechanically mixing at least the binder resin, the main charge control agent and the pigment, and the developer component including the by-product may be performed under normal conditions using a normal mixer using a rotating wing, There is no particular limitation.
[0080]
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. 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 KC Co., Ltd., PCM type twin screw extruder manufactured by Ikegai Iron Works, manufactured by Bus A kneader or the like is preferably used.
[0081]
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.
[0082]
When the above melt-kneading process is completed, the kneaded product is then pulverized. In this pulverization step, it is preferable to first perform coarse pulverization and then fine pulverization. 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 mechanically rotating rotor and a stator is preferably used.
[0083]
After the pulverization step is completed, the pulverized product is classified in an air stream by centrifugal force or the like to produce a developer having a predetermined particle size, for example, an average particle size of 5 to 20 μm.
[0084]
In addition, when preparing the developer, in order to improve the fluidity, storage stability, developability, and transferability of the developer, the hydrophobic silica fine particles listed above are further listed in the developer produced as described above. Inorganic fine particles such as powder may be added and mixed.
[0085]
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.
[0086]
(Full color image development method)
In the non-magnetic one-component development method using a conductive brush according to the present invention, a non-magnetic one component is developed by sequentially performing a number of times of development using a full color toner having a specific circularity, and sequentially transferring the toner onto a transfer medium. In the component full color process, the effect can be effectively used particularly for the uniform reproducibility of the halftone.
[0087]
The full-color non-magnetic one-component image forming method of the present invention is a conductive brush formed by a plurality of multi-color developing devices including a developing roller and a developing blade that uniformly regulates the layer thickness of the developer supplied onto the developing roller. In this method, the electrostatic latent image divided on each color formed on the photosensitive member by the charger and the exposure device is sequentially developed with a developer corresponding to each color and transferred to a transfer medium.
[0088]
The full-color non-magnetic one-component image forming method of the present invention includes a developing roller and a plurality of multi-color developing devices provided with a developing blade that uniformly regulates the layer thickness of the developer supplied onto the developing roller. An electrostatic latent image divided into each color is formed on a plurality of photoconductors corresponding to each color by a conductive brush charger and an exposure device, sequentially developed with a corresponding color developer, and transferred to a transfer medium. It is a method to do. 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.
[0089]
【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.
[0090]
(Synthesis example of charge control resin)
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 1.1% by weight. Weight average molecular weight 25000, apparent viscosity 10 ^Four P (10 ^Four P = 10 ^Four The charge control resin A having a temperature of 96 ° C. was obtained.
[0091]
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 3.6% by weight. Weight average molecular weight 5300, apparent viscosity 10 ^Four P (10 ^Four P = 10 ^Four g / cm · s) was obtained as a charge control resin B having a temperature of 85 ° C.
[0092]
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, weight average molecular weight 98000, apparent viscosity 10 ^Four P (10 ^Four P = 10 ^Four g / cm · s) was obtained as a charge control resin C having a temperature of 110 ° C.
[0093]
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, and the volatile content was 1.7% by weight, the weight average molecular weight was 50000, Apparent viscosity is 10 ^Four P (10 ^Four P = 10 ^Four The charge control resin D having a temperature of 105 ° C. was obtained.
[0094]
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. Weight average molecular weight 30000, apparent viscosity 10 ^Four P (10 ^Four P = 10 ^Four g / cm · s) was obtained as a charge control resin E having a temperature of 101 ° C.
[0095]
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 dryer. The volatile content was 0.6% by weight, the weight average molecular weight was 115000, and the apparent viscosity was 10%. ^Four P (10 ^Four P = 10 ^Four g / cm · s) was obtained as a charge control resin F having a temperature of 110 ° C.
[0096]
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 5.1% by weight, the weight average molecular weight was 2800, and the apparent viscosity. 10 ^Four P (10 ^Four P = 10 ^Four g / cm · s) was obtained as a charge control resin G having a temperature of 80 ° C.
[0097]
(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 allowed to proceed 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).
[0098]
Synthesis example 2
71,225 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).
[0099]
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).
[0100]
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).
[0101]
(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 carried out 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).
[0102]
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 to 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 to 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).
[0103]
(Toner Production Example 1)
600 parts of water
C. I. Pigment Yellow 180
Water-containing cake (solid content 50%) 1200 parts
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.
[0104]
100 parts of polyester resin A
5 parts of the above master batch
Charge control resin A 1.5 parts
The above materials were mixed with a 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 6.0 μm and a volume average diameter of 7.1 μm (Dv / Dn = 1.2). The pulverization amount per unit time at that time was 2.3 kg / H.
[0105]
(Mixing with external additives and evaluation of the obtained toner)
100 parts by weight of the obtained colored particles of 4 colors and 1.0 part by weight of hydrophobic silica A (Wacker HDK H2000) and 1.0 part by weight of hydrophobic silica C (Aerosil RX-50, Nippon Aerosil Co., Ltd.) Part, hydrophobic titanium oxide E (Taika MT-150AI) 0.5 part by weight is mixed with a Henschel mixer, and the coarse particles and aggregates are removed by passing through a mesh with an opening of 100 μm, so that toner T1 for electrophotography Got.
Table 1 shows the external additives used, and Table 2 shows the combination of the binder resin and the charge control agent and the obtained toner.
[0106]
(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. It was carried out with a laser printer Ypsio 5000 (manufactured by Ricoh).
[0107]
(Evaluation item)
In each item, an image chart having a 5% image area was continuously run up to 100,000 sheets, and the following evaluation was performed.
1) Image density
After outputting a 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.
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 (manufactured by X-Rite).
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.
[0108]
4) Physical property measurement
4-1) [Particle size]
The particle size of the toner was measured with a particle size measuring device “Coulter Counter TAIII, manufactured by Coulter Electronics Co., Ltd., at an aperture diameter of 100 μm. The volume average particle size and the number average particle size were determined by the above particle size measuring device.
4-2) [Charge amount]
(Charge Amount) The charge amount of the toner in the present invention indicates the charge amount when the toner and the carrier are mixed to form a developer. The toner concentration (TC) in the developer at this time is 3 to 5% by weight. TC is obtained as follows.
TC (% by weight) =
(Toner weight) / [(toner weight) + (carrier weight)] × 100
6 g of developer prepared with toner and carrier is put into a cylindrical stainless steel bottle having a diameter of 2.5 cm and a height of 3.0 cm, and stirred at a speed of 250 rpm with a ball mill for a predetermined time to blow off the charge amount of the toner. Measure by the method. (Uses Powder Tech FPC-300 for carrier)
In the case of an experimental machine: Toner was conveyed onto a developing roller (sleeve) and measured by a suction tribo measurement method.
[0109]
5) Dispersed particle size 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.
6) Transparency
A sample was prepared with an OHP sheet at 160 ° C. with a fixing speed of 90 mm / sec. This was measured for transparency using a haze meter (Suga Test Machine Co., Ltd.). Those having a haze of 15% or less were evaluated as ◯, those having less than 30% were evaluated as Δ, and those having 30% or more were evaluated as ×.
7) Volatile content
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
[0110]
Other toner production examples are summarized in Table 2. A toner was prepared in the same manner as in Example 1 except for the toner particle diameter, the charge control resin and its addition amount, and the binder resin. In addition, Table 3 summarizes the results of actual machine evaluation of Examples and Comparative Examples.
[0111]
Table 1 below shows the external additives used.
[Table 1]

[0112]
Table 2 below shows the toner formulation.
[Table 2]

[0113]
Table 3 below shows the actual machine evaluation results.
[Table 3]

[0114]
【The invention's effect】
According to the present invention, in any one of the one-component color development methods, there is no filming on the photosensitive member, the developer layer thickness regulating member and the developing sleeve after long-term continuous printing, compared to the conventional one, An electrophotographic yellow toner capable of stabilizing the charging and conveying of the toner and maintaining 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 contamination, 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 recycles and wastes generated after use than conventional ones, and the user has to replace the imaging unit. Can be reduced.

Claims (14)

In yellow toner used for full-color image formation to reproduce multicolor images,
(A) a binder resin containing a polyester resin or a polyol resin having an acid value of 20 KOH mg / g or less,
(B) C.I. I. A compound classified as Pigment Yellow 180,
(C) The sulfonate group-containing monomer (1), the aromatic monomer (2) having an electron withdrawing group, and at least one (3) selected from an acrylate monomer or a methacrylic acid ester monomer are used as structural units. And a resin negative charge control agent having a volatile content of 5% or less,
A yellow toner comprising at least The resin negative charge control agent (C) comprises a sulfonate group-containing monomer (1), an aromatic monomer (2) having an electron withdrawing group, an acrylate monomer or a methacrylic acid ester monomer, and a styrene vinyl monomer. The yellow toner according to claim 1, wherein the yellow toner is composed of a polymerization component (3) as a structural unit. The repeating unit of the sulfonic acid group-containing monomer is 1 to 30% by weight based on the weight of the resin negative charge control agent, and the repeating unit of the aromatic monomer having an electron withdrawing group is 1 to 1 weight based on the weight of the resin negative charge control agent. 80% by weight, 10 to 80% by weight of the repeating unit of the acrylate monomer and / or methacrylic acid ester monomer based on the weight of the resin negative charge control agent, and the repeating unit of the aromatic vinyl monomer is the weight of the resin negative charge control agent The toner for electrophotography according to claim 1, wherein the toner is contained at a ratio of 0 to 30% by weight with respect to the toner. The electron according to any one of claims 1 to 3, 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. Toner for photography. The apparent viscosity by the flow tester of the resin negative charge control agent is 10 ⁴ P (10 ⁴ P = 10 ⁴ The toner for electrophotography according to any one of claims 1 to 4, wherein a temperature of g / cm · s) is 85 to 110 ° C. 6. The electrophotographic toner according to claim 1, wherein the resin negative charge control agent has a weight average molecular weight of 5,000 to 100,000. The electrophotographic toner according to claim 1, wherein the resin negative charge control agent is contained in an amount of 0.1 to 2 wt% with respect to the toner particles. The toner particles have a BET specific surface area of 110 m. ² / G of hydrophobic silica particles and BET specific surface area of 50m ² The toner for developing an electrostatic charge image according to claim 1, wherein hydrophobic toner particles of not more than / g are added and titanium oxide particles are further added. 9. The relationship between the number average particle diameter and the volume average particle diameter of the toner particles is volume average particle diameter (Dv) / number average particle diameter (Dn) ≦ 1.4. The toner for developing an electrostatic charge image according to 1. A container containing the toner according to claim 1. An image forming apparatus comprising the container according to claim 10. 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: at least a transfer step; and a fixing step of fixing a toner image on a transfer body by heating, and using the toner according to claim 1 as a developer. 13. The image forming method according to claim 12, wherein in the developing step, a thin layer of the developer is formed on the developer carrying member, and development is performed in contact with or non-contact with the latent image holding member. In the latent image forming step, the latent image to be formed is an electrostatic latent image divided into multiple colors, and held by a plurality of latent image holding bodies corresponding to the colors of the electrostatic latent image, In the developing step, the developer is a plurality of developers corresponding to the colors of the electrostatic latent image, and the electrostatic latent images on the plurality of latent image holding bodies respectively corresponding to the plurality of developers are Development is performed using a plurality of multi-color 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. 14. The image forming method according to claim 12, wherein a 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.