JP2004133381A - Toner kit, deep-color toner, light-color toner, and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce granularity and roughness from a low density region to a high density region and to form a higher quality image. <P>SOLUTION: Image formation is performed using a light-color toner comprising at least a binder resin and colorants and satisfying prescribed conditions with respect to hues represented by an L*a*b* color system in which a hue in red-green direction is a*, a hue in yellow-blue direction is b*, and lightness is L*, and a deep-color toner comprising at least a binder resin and colorants and satisfying prescribed conditions with respect to hues represented by the L*a*b* color system. <P>COPYRIGHT: (C)2004,JPO

Description

【００３０】
前記Ｌ^＊　_Ｃ１及びＬ^＊　_Ｃ２が上記範囲にあることで、粒状感低減の効果を保持しつつ画像の鮮やかさを向上し、色再現範囲を拡張することが可能となる。Ｌ^＊　_Ｃ１が８５未満であると低濃度部の粒状感低減の効果が小さくなる場合があり、Ｌ^＊　_Ｃ１が９０を超える範囲であると、中濃度部の粒状感低減の効果が小さくなる場合がある。Ｌ^＊　_Ｃ２が７４未満であると、中濃度部の粒状感低減の効果が小さくなる場合があり、Ｌ^＊　_Ｃ２が８４を超える範囲であると、高濃度部の階調性が十分に得られない場合がある。
【００３１】
本発明では、淡色シアントナーは色相角度（Ｈ^＊　_Ｃ１）が２１４乃至２２６°であり、濃色シアントナーは色相角度（Ｈ^＊　_Ｃ２）が２２８乃至２６０°であることが好ましい。前記色相角度は、図２に示すように、ａ^＊−ｂ^＊座標において、紙上のトナー付着量が０．５ｍｇ／ｃｍ^２の画像の色相（ａ^＊，ｂ^＊）と原点とを結ぶ直線と、正のａ^＊軸とがなす角度であり、正のａ^＊軸から反時計回りの方向において、前記直線と正のａ^＊軸とがなす角度である。色相角度は、明度とは無関係に特定の色相を容易に表すことができる。
【００３２】
Ｈ^＊　_Ｃ１が２２６°を超えると、低濃度部の粒状感低減の効果が小さくなる場合があり、Ｈ^＊　_Ｃ１が２１４°未満であると、中濃度部の粒状感低減の効果が小さくなる場合がある。Ｈ^＊　_Ｃ２が２６０°を超えると、中濃度部の粒状感低減の効果が小さくなる場合があり、Ｈ^＊　_Ｃ２が２２８°未満であると、高濃度部の階調性が十分に得られない場合がある。
【００３３】
次に、マゼンタトナーに関して記載する。
【００３４】
本発明に用いられる淡色マゼンタトナーと濃色マゼンタトナーとは、Ｌ^＊ａ^＊ｂ^＊系表色系によって普通紙上のトナー定着画像を表したとき、淡色マゼンタトナーは、淡色マゼンタトナーの定着画像におけるａ^＊が２０のときのｂ^＊の値（ｂ^＊ _Ｍ１）が−１８乃至０であり、ａ^＊が３０のときのｂ^＊の値（ｂ^＊　_Ｍ２）の値が−２６乃至０であり、濃色マゼンタトナーは、濃色マゼンタトナーの定着画像におけるａ^＊が２０のときのｂ^＊の値（ｂ^＊　_Ｍ３）が−１６乃至２であり、ａ^＊が３０のときのｂ^＊の値（ｂ^＊　_Ｍ４）が−２４乃至＋３であり、ｂ^＊　_Ｍ１とｂ^＊　_Ｍ３との差（ｂ^＊　_Ｍ１−ｂ^＊　_Ｍ３）が−８乃至−１であり、ｂ^＊　_Ｍ２とｂ^＊　_Ｍ４との差（ｂ^＊　_Ｍ２−ｂ^＊　_Ｍ４）が−１２乃至−１である。
【００３５】
本発明において、ｂ^＊　_Ｍ１が−１８乃至０であり、かつｂ^＊　_Ｍ２が−２６乃至０である淡色マゼンタトナーと、ｂ^＊　_Ｍ３が−１６乃至２であり、かつｂ^＊　_Ｍ４が−２４乃至３である濃色マゼンタトナーとを用いることで、前述の課題を解決し、低濃度部から高濃度領域まで、粒状感がなく、階調性に優れ、色再現範囲の広い良好な画像を得ることができる。また、本発明においては、上記の観点より、ｂ^＊　_Ｍ１が−１３乃至−４であり、かつｂ^＊　_Ｍ２が−１５乃至−５である淡色マゼンタトナーと、ｂ^＊　_Ｍ３が−１２乃至０（更に好ましくは、ｂ^＊　_Ｍ３が−１１乃至−２）であり、かつｂ^＊　_Ｍ４が−１５乃至０（更に好ましくは、ｂ^＊　_Ｍ４が−１４乃至−４）であることがより好ましい。
【００３６】
マゼンタトナーにより形成された画像には、人間に対する感度が大きい色味と比較的感度が小さい色味とがある。赤色に近いマゼンタとして形成された画像は、画像濃度の変化率が小さい高濃度部においても階調性を認識されやすい。更に、画像にドットやラインで存在する低濃度部では、ドットやラインのゆらぎを粒状感として感知されやすい特徴がある。一方、紫色に近いマゼンタとして形成された画像は、ドットやラインがある程度乱れていても粒状感として感知されにくい特徴がある。前述の色相範囲によれば、淡色マゼンタトナーと濃色マゼンタトナーとが混在した中濃度部においても粒状感が良好に抑制される。
【００３７】
ｂ^＊　_Ｍ１が０より大きい（正の値となる）場合や、ｂ^＊　_Ｍ２が０より大きい場合では、低濃度部の粒状感が増大しやすく、ｂ^＊　_Ｍ１が−１８より小さい（負に大）場合や、ｂ^＊　_Ｍ２が−２６より小さい場合では、中濃度部の粒状感が増大することがある。ｂ^＊　_Ｍ３が２より大きい場合や、ｂ^＊　_Ｍ４が３より大きい場合では、中濃度部の粒状感が増大しやすく、ｂ^＊　_Ｍ３が−１６より小さい場合や、ｂ^＊　_Ｍ４が−２４より小さい場合では、高濃度部において十分な階調性が得られないことがある。
【００３８】
また、本発明において、前記ｂ^＊　_Ｍ１とｂ^＊　_Ｍ３との差（ｂ^＊　_Ｍ１−ｂ^＊　_Ｍ３）が−８乃至−１であり、ｂ^＊　_Ｍ２とｂ^＊　_Ｍ４との差（ｂ^＊　_Ｍ２−ｂ^＊　_Ｍ４）が−１２乃至−１であることを特徴とする。また、ｂ^＊　_Ｍ１とｂ^＊　_Ｍ３との差（ｂ^＊　_Ｍ１−ｂ^＊　_Ｍ３）は、−７乃至−１であることがより好ましく、更に好ましくは−７乃至−２であり、ｂ^＊　_Ｍ２とｂ^＊　_Ｍ４との差（ｂ^＊　_Ｍ２−ｂ^＊　_Ｍ４）は、−１１乃至−２であることがより好ましく、更に好ましくは−１０乃至−２である。ｂ^＊　_Ｍ１−ｂ^＊　_Ｍ３が−１より大きい場合や、ｂ^＊　_Ｍ２−ｂ^＊　_Ｍ４が−１より大きい場合では、低濃度部から高濃度部まで表現可能な階調の幅が小さくなる場合がある。ｂ^＊ _Ｍ１−ｂ^＊　_Ｍ３が−８より小さい場合や、ｂ^＊　_Ｍ２−ｂ^＊　_Ｍ４が−１２より小さい場合では、低濃度部から高濃度部まで連続した粒状感低減の効果が小さくなる場合がある。淡色マゼンタトナー及び濃色マゼンタトナーの色相範囲は、着色剤の種類や含有量、トナー粒径等を制御することにより達成される。
【００３９】
更に上記効果は、淡色マゼンタトナーと濃色マゼンタトナーとが互いに同極性の摩擦帯電特性を有し、両マゼンタトナーの二成分トリボ値の差が絶対値で５ｍＣ／ｋｇ以下であるときに特に顕著となり、低濃度部から高濃度領域まで、粒状感がなく、階調性に優れた良好な画像を得ることが可能となる。
【００４０】
トナーの二成分トリボ値は、公知の方法によって測定することができる。本発明では、図１８に示す二成分トリボ値を測定する装置で測定することが好ましい。先ず、底に５００メッシュのスクリーン９３のある金属製の測定容器９２に二成分トリボ値を測定しようとする試料とキャリアとの混合物、すなわち、トナーの場合には、トナーとキャリアの質量比１：１９の混合物、また、外添剤の場合には、外添剤とキャリアの質量比１：９９の混合物を５０乃至１００ｍｌ容器のポリエチレン製の瓶に入れ、約１０乃至４０秒間手で振とうし、該混合物（現像剤）約０．５乃至１．５ｇを入れ金属製のフタ９４をする。この時の測定容器９２全体の質量をＷ１（ｇ）とする。次に吸引機９１（測定容器９２と接する部分は少なくとも絶縁体）において、吸引口９７から吸引し風量調節弁９６を調整して真空計９５の圧力を２５０ｍｍＡｑとする。この状態で充分、好ましくは２分間吸引を行いトナーを吸引除去する。この時の電位計９９の電位をＶ（ボルト）とする。ここで９８はコンデンサーであり容量をＣ（ｍＦ）とする。また、吸引後の測定容器全体の質量を秤り、このときの値をＷ２（ｇ）とする。この試料の二成分トリボ値（ｍＣ／ｋｇ）は下式の如く算出される。
試料の二成分トリボ値（ｍＣ／ｋｇ）＝Ｃ×Ｖ／（Ｗ１−Ｗ２）
（但し、測定条件は２３℃，６０％ＲＨとする。）
測定に用いるキャリアとしては、２５０メッシュパス・３５０メッシュオンのキャリア粒子が７０〜９０質量％有するコートフェライトキャリアを使用した。
【００４１】
具体的には、以下のようにして製造したキャリアを用いた。
【００４２】
トルエン２０部、ブタノール２０部、水２０部、氷４０部を四つ口フラスコにとり、攪拌しながら、ＣＨ_３ＳｉＣｌ_３：２モルと（ＣＨ_３）_２ＳｉＣｌ_２：３モルとの混合物４０部を加え、更に３０分間攪拌した後、６０℃で１時間縮合反応を行いシリコーン樹脂を得た。
・上記シリコーン樹脂（オルガノポリシロキサンシリコーンレジン）１００部
・Ｃ_６Ｈ_５−ＮＨＣＨ_２ＣＨ_２ＣＨ_２Ｓｉ（ＯＣＨ_３）_３　　　　　　　２部
上記の原材料の混合物を、Ｃｕ−Ｚｎ−Ｆｅ系フェライトコアに０．５質量％コーティングしてキャリアを製造した。このシリコーン樹脂コートフェライトキャリアは、ＸＰＳ測定によるキャリア粒子表面の原子数比がＳｉ／Ｃ＝０．６であり、金属原子であるＣｕ、Ｚｎ、Ｆｅの原子数の合計が、０．５個数％であった。重量平均粒径は４２μｍ、重量分布において粒径２６μｍ以上３５μｍ未満の粒子が１９重量％、粒径７０μｍ以上の粒子が０重量％であり、５００Ｖの電圧を印加したときの電流値が７０μＡであった。
【００４３】
本発明では、前記淡色マゼンタトナーは、ｃ^＊が３０のときのＬ^＊の値（Ｌ^＊ _Ｍ１）が７８至９０であり、前記濃色マゼンタトナーは、ｃ^＊が３０のときのＬ^＊の値（Ｌ^＊　_Ｍ２）が７４乃至８７であり、Ｌ^＊　_Ｍ１とＬ^＊　_Ｍ２との差（Ｌ^＊　_Ｍ１−Ｌ^＊　_Ｍ２）が０．４乃至１２であることが好ましい。
【００４４】
前記Ｌ^＊　_Ｍ１及びＬ^＊　_Ｍ２が上記範囲にあることで、粒状感低減の効果を保持しつつ画像の鮮やかさを向上し、色再現範囲を拡張することが可能となる。Ｌ^＊　_Ｍ１が７８未満であると低濃度部の粒状感低減の効果が小さくなる場合があり、Ｌ^＊　_Ｍ１が９０を超える範囲であると、中濃度部の粒状感低減の効果が小さくなる場合がある。Ｌ^＊　_Ｍ２が７４未満であると、中濃度部の粒状感低減の効果が小さくなる場合があり、Ｌ^＊　_Ｍ２が８７を超える範囲であると、高濃度部の階調性が十分に得られない場合がある。また、（Ｌ^＊　_Ｍ１−Ｌ^＊　_Ｍ２）が０．４未満であると、色再現範囲を拡張する効果が小さくなる場合があり、（Ｌ^＊　_Ｍ１−Ｌ^＊　_Ｍ２）が１２を超える範囲であると、粒状感低減の効果が小さくなる場合がある。
【００４５】
本発明では、淡色マゼンタトナーは色相角度（Ｈ^＊　_Ｍ１）が３２５乃至３５０°であり、濃色マゼンタトナーは色相角度（Ｈ^＊　_Ｍ２）が３４０乃至１０°であり、Ｈ^＊　_Ｍ１とＨ^＊　_Ｍ２とのなす角度（Ｈ^＊　_Ｍ２−Ｈ^＊　_Ｍ１）が２乃至３０°であることが好ましい。前記色相角度は、濃淡シアントナーの場合と同様にして測定することができる。
【００４６】
Ｈ^＊　_Ｍ１が３５０°を超えると、低濃度部の粒状感低減の効果が小さくなる場合があり、Ｈ^＊　_Ｍ１が３２５°未満であると、中濃度部の粒状感低減の効果が小さくなる場合がある。Ｈ^＊　_Ｍ２が１０°を超えると、中濃度部の粒状感低減の効果が小さくなる場合があり、Ｈ^＊　_Ｍ２が３４０°未満であると、高濃度部の階調性が十分に得られない場合がある。また、（Ｈ^＊　_Ｍ２−Ｈ^＊　_Ｍ１）が２未満であると、色再現範囲を拡張する効果が小さくなる場合があり、（Ｈ^＊　_Ｍ２−Ｈ^＊　_Ｍ１）が３０を超える範囲であると、粒状感低減の効果が小さくなる場合がある。
【００４７】
次に、シアントナー及びマゼンタトナーに共通した事項を記載する。
【００４８】
本発明に用いられるトナーのａ^＊、ｂ^＊、ｃ^＊、Ｌ^＊は、それぞれのトナーを用いて普通紙上に適当なトナー定着画像を形成し、この画像の色相や明度を測定することにより求められる。トナー定着画像を形成するための画像形成装置には、市販の普通紙フルカラー複写機（例えばカラーレーザー複写機ＣＬＣ１１５０；キヤノン製）を用いることができる。前記普通紙には、例えばカラーレーザーコピア用紙ＴＫＣＬＡ４；キヤノン製を用いることができる。前記適当なトナー定着画像には、紙上のトナー量を変化させた画像、例えば２００線１６階調画像（１インチ当り２００本の線画像を用いて、図７と同様に１６階調の画像を形成したもの）を用いることができる。
【００４９】
即ち、本発明においては、一般に用いられる装置を用い、用いた装置に応じた良好な画像形成が行える条件で、画出しした場合に、定着画像におけるａ^＊、ｂ^＊、ｃ^＊、Ｌ^＊が本発明の規定を満たすものは、本発明の範囲内であるものと考える。
【００５０】
測定方法は、前記ａ^＊、ｂ^＊、及びＬ^＊を少なくとも測定できる方法であれば特に限定されないが、例えばＳｐｅｃｔｒｏＳｃａｎ　Ｔｒａｎｓｍｉｓｓｉｏｎ（Ｇｒｅｔａｇ　Ｍａｃｂｅｔｈ社製）を測定装置として用いて測定する方法が挙げられる。この装置を用いる場合の測定条件としては、観測光源：Ｄ５０、観測視野：２°、濃度：ＤＩＮ　ＮＢ、白色基準：Ｐａｐ、フィルター：無し、を例示することができる。
【００５１】
ａ^＊を横軸、ｂ^＊を縦軸として、前記トナー定着画像の測定により得られたａ^＊の値及びｂ^＊の値をプロットし、ａ^＊−ｂ^＊座標図を作成する。このａ^＊−ｂ^＊座標図から、ｂ^＊が−２０及び−３０のときのａ^＊の値を求める。代表的な測定結果を図３及び５に示す。
【００５２】
さらに、ｃ^＊を横軸、Ｌ^＊を縦軸として、前記ａ^＊−ｂ^＊座標図及び前記式から得られたｃ^＊の値及びＬ^＊の値をプロットし、ｃ^＊−Ｌ^＊座標図を作成する。このｃ^＊−Ｌ^＊座標図から、ｃ^＊が３０のときのＬ^＊の値を求める。代表的な測定結果を図４及び６に示す。
【００５３】
本発明において、淡色シアントナー及び濃色シアントナーに用いることのできる着色剤としては、銅フタロシアニン化合物及びその誘導体、アンスラキノン化合物、塩基染料レーキ化合物等が挙げられる。特に好適に利用できる着色剤としては、具体的には、Ｃ．Ｉ．ピグメントブルー１、７、１５、１５：１、１５：２、１５：３、１５：４、６０、６２、６６が挙げられる。淡色シアントナー及び濃色シアントナーに用いることのできる着色剤には、前述したシアン着色剤の他に、例えば後述のイエロー着色剤やマゼンタ着色剤等の他色の着色剤を用いても良く、これらの着色剤を混合することによってａ^＊、ｂ^＊、ｃ^＊、Ｌ^＊の値を調整することが可能である。
【００５４】
本発明において、淡色マゼンタトナー及び濃色マゼンタトナーに用いることのできる着色剤としては、縮合アゾ化合物、ジケトピロロピロール化合物、アンスラキノン、キナクリドン化合物、塩基染料レーキ化合物、ナフトール化合物、ベンズイミダゾロン化合物、チオインジゴ化合物、ペリレン化合物が挙げられる。特に好適に利用できる着色剤としては、Ｃ．Ｉ．ピグメントレッド３１、４８：１、４８：２、４８：３、４８：４、５７：１、８８、９５、１４４、１４６、１５０、１７７、２０２、２１４、２２０、２２１、２５４、２６４、２６９、Ｃ．Ｉ．ピグメントバイオレット１９が挙げられる。淡色マゼンタトナー及び濃色マゼンタトナーに用いることのできる着色剤には、前述したマゼンタ着色剤の他に、例えば後述のイエロー着色剤やシアン着色剤等の他色の着色剤を用いても良く、これらの着色剤を混合することによってａ^＊、ｂ^＊、ｃ^＊、Ｌ^＊の値を調整することが可能である。
【００５５】
これらの着色剤は、単独で、又は混合した状態で用いることができ、さらには固溶体の状態でも用いることができる。着色剤は、色相角度、彩度、明度、耐候性、ＯＨＰ透明性、トナー粒子中への分散性の点から選択される。本発明における着色剤には、顔料を用いることが好ましい。本発明における着色剤の好ましい添加量は、使用する着色剤の種類等によって異なるが、淡色シアントナー及び淡色マゼンタトナーは、トナー全量に対し０．４乃至１．５質量％であり、濃色シアントナー及び濃色マゼンタトナーは、トナー全量に対し２．５〜８．５質量％である。
【００５６】
本発明では、微小な潜像を忠実に現像し、低濃度部から高濃度領域まで、粒状感がなく、階調性に優れた良好な画像を得るために、前記淡色トナー（シアン、マゼンタ）の重量平均粒子径（Ｄａ）及び前記濃色トナー（シアン、マゼンタ）の重量平均粒子径（Ｄｂ）はそれぞれ３乃至９μｍであることが好ましい。Ｄａ及びＤｂが前記範囲にあると、転写効率の低下が少なく、カブリや転写不良に基づく画像の不均一ムラが発生しにくい。
【００５７】
本発明では、低濃度部から高濃度領域まで粒状感がなく、階調性に優れた画像を形成しつつ、より高精細の画像を得るために、上記ＤａとＤｂとの比（Ｄａ／Ｄｂ）が１．０乃至１．５の範囲であることが好ましく、更には１．０５乃至１．４の範囲がより好ましい。Ｄａ及びＤｂは、重合法等のトナーの製造方法によって調整することができ、また、生成したトナー粒子の分級や分級品の混合によって調整することができる。
【００５８】
トナーの平均粒径及び粒度分布は、公知の方法によって測定することができる。本発明では、コールターカウンターＴＡ−ＩＩ型あるいはコールターマルチサイザー（コールター社製）の如き測定機を用いて測定することが好ましい。
【００５９】
このような測定方法では、コールターカウンターＴＡ−ＩＩ型あるいはコールターマルチサイザー（コールター社製）の如き測定機と、個数分布、体積分布を出力するインターフェース（日科機製）及びＰＣ９８０１パーソナルコンピューター（ＮＥＣ製）とを接続して用い、電解液を用いる。電解液には、１級塩化ナトリウムを用いて調製された１％ＮａＣｌ水溶液や、例えばＩＳＯＴＯＮ　Ｒ−ＩＩ（コールターサイエンティフィックジャパン社製）を用いることができる。
【００６０】
具体的な測定法としては、前記電解水溶液１００〜１５０ｍｌ中に、分散剤として界面活性剤（好ましくはアルキルベンゼンスルホン酸塩）を０．１〜５ｍｌ加え、さらに測定試料を２〜２０ｍｇ加え、超音波分散器で約１〜３分間分散処理を行い、これを前記測定機で測定する。例えばアパーチャーとして１００μｍアパーチャーを用いて、前記コールターカウンターＴＡ−ＩＩ型により、２μｍ以上のトナーの体積、個数を測定して体積分布と個数分布とを算出する。それから、重量平均粒子径（Ｄ４）、及び、個数平均粒子径（Ｄ１）を求める。
【００６１】
本発明に用いられる淡色シアントナー、濃色シアントナー、淡色マゼンタトナー及び濃色マゼンタトナーは、前記着色剤の他に、結着樹脂、離型剤、及び荷電制御剤等の公知のトナー材料によって構成される。
【００６２】
本発明では、荷電制御剤は、両シアントナーの帯電特性を好適に調整する目的で用いられる。なお、両シアントナーの帯電特性は、他のトナー材料の種類や、画像形成時にトナーの摩擦帯電を制御すること等によっても調整することが可能である。
【００６３】
本発明に用いられる荷電制御剤には、公知のものを用いることができるが、特に、無色で、トナーの帯電スピードが速く、かつ一定の帯電量を安定して維持できる荷電制御剤が好ましい。さらに、重合法でトナー粒子を製造する場合には、重合阻害性がなく、水系への可溶化物のない荷電制御剤が特に好ましい。荷電制御剤には、ネガ系荷電制御剤やポジ系荷電制御剤が用いられる。
【００６４】
ネガ系荷電制御剤としては、サリチル酸金属化合物、ナフトエ酸金属化合物、ダイカルボン酸金属化合物、スルホン酸又はカルボン酸を側鎖に持つ高分子型化合物、ホウ素化合物、尿素化合物、ケイ素化合物、カリックスアレーンが利用できる。ポジ系荷電制御剤としては、四級アンモニウム塩、該四級アンモニウム塩を側鎖に有する高分子型化合物、グアニジン化合物、イミダゾール化合物が利用できる。荷電制御剤は、結着樹脂１００質量部に対し０．５〜１０質量部が好ましい。
【００６５】
本発明では、前記淡色トナー（シアン、マゼンタ）及び前記濃色トナー（シアン、マゼンタ）は、それぞれ荷電制御剤を含有し、淡色トナーの荷電制御剤の含有量（Ｃａ）と、濃色トナーの荷電制御剤の含有量（Ｃｂ）との比（Ｃａ／Ｃｂ）が０．５乃至１．０であることが好ましく、より０．６０乃至０．９５であることが好ましい。濃色トナーの帯電スピードは、淡色トナーの帯電スピードに対し遅くなりやすい。このため、濃色トナーの荷電制御剤を多くすることで、両トナーの帯電特性が同程度に制御され、中濃度領域の粒状感が抑制の効果が一層得られる。
【００６６】
本発明では、前記濃色トナー（シアン、マゼンタ）は、紙上のトナー量が１ｍｇ／ｃｍ^２であるベタ画像の光学濃度が１．５乃至２．５であり、前記淡色シアントナー（シアン、マゼンタ）は、紙上のトナー量が１ｍｇ／ｃｍ^２であるベタ画像の光学濃度が０．８２乃至１．３５であることが好ましい。前記光学濃度が前記範囲であると、トナー消費量の増大をより抑制し、より効率よく高画質画像を得ることができる。前記光学濃度は、トナーの着色力、現像性、及び帯電特性等、現像から定着までのトナーの物性を、使用するトナー材料の種類、トナーの製造方法、及び画像形成プロセス等によって制御することにより調整することが可能である。
【００６７】
本発明では、転写効率を向上させるという観点から、前記淡色トナー（シアン、マゼンタ）及び前記濃色トナー（シアン、マゼンタ）は、チタニア、アルミナ、シリカ、及びそれらの複酸化物からなるグループから選ばれる無機微粉体をそれぞれ有することが好ましい。また、ＢＥＴ法によって測定された淡色トナーの比表面積の値（Ｓａ）と、濃色トナーの比表面積の値（Ｓａ）との比（Ｓａ／Ｓｂ）が０．５乃至１．０の範囲であることが好ましく、更には０．６乃至０．９５であることがより好ましい。また、Ｓａ／Ｓｂが上記範囲にあることで、両淡色トナー及び両濃色トナーの転写効率を揃えることができ、これらにより、トナーが画像中で混在する中濃度領域の粒状感がさらに抑制され、より一層良好な画像が得られる。
【００６８】
上記範囲のトナーの比表面積は、トナー粒子の比表面積とトナー粒子に添加する無機微粉体の比表面積、添加量及び添加混合強度を制御することで達成される。添加混合強度が強すぎると、無機微粒子がトナー粒子中に埋め込まれてしまい、転写効率の向上が少ない。
【００６９】
比表面積は、ＢＥＴ法にしたがって、比表面積測定装置（例えばオートソーブ１（湯浅アイオニクス社製））を用いて、試料表面に窒素ガスを吸着させ、ＢＥＴ多点法を用いることにより求められる。６０％細孔半径は、脱離側の細孔半径に対する積算細孔面積比率曲線から求める。オートソーブ１においては、細孔分布の計算はＢａｒｒｅｔｔ，　Ｊｏｙｎｅｒ　＆　Ｈａｒｅｎｄａ（Ｂ．Ｊ．Ｈ）によって考えられたＢ．Ｊ．Ｈ法で行う。
【００７０】
前記淡色トナー及び濃色トナーに用いられる結着樹脂には、公知の結着樹脂を用いることができる。
【００７１】
トナーに含有される樹脂成分としては、テトラヒドロフラン（ＴＨＦ）可溶分のゲルパーミエーションクロマトグラフィー（ＧＰＣ）の分子量分布において、分子量６００〜５００００の範囲にピークを有することが好ましい。結着樹脂としては、低分子量成分と高分子量成分とを含有していることが好ましく、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）の分子量分布において、低分子量のピークが３０００〜１５０００の範囲にあることが、粉砕法で生成したトナーの形状を熱と機械的衝撃力でコントロールする上で好ましい。低分子量のピークが１５０００を超えると、転写効率の向上が不十分になりやすく、分子量３０００未満では、トナー粒子の表面処理時に融着を生じやすい。
【００７２】
前記分子量は、ＧＰＣにより測定される。具体的なＧＰＣの測定方法としては、ソックスレー抽出器を用いてトナーを予めテトラヒドロフラン（ＴＨＦ）で２０時間抽出し、得られた抽出液をサンプルとし、昭和電工製Ａ−８０１、８０２、８０３、８０４、８０５、８０６、８０７を連結したカラム構成で、標準ポリスチレン樹脂の検量線を用い分子量分布を測定する方法が挙げられる。
【００７３】
本発明では、結着樹脂は、質量平均分子量（Ｍｗ）と数平均分子量（Ｍｎ）の比率（Ｍｗ／Ｍｎ）は、２〜１００を示す樹脂であることが好ましい。
【００７４】
本発明では、両淡色トナー及び両濃色トナーのガラス転移点（Ｔｇ）は、定着性、保存性の点から５０℃〜７５℃（さらに好ましくは、５２℃〜７０℃）が好ましい。
【００７５】
トナーのガラス転移点の測定には、例えばパーキンエルマー社製のＤＳＣ−７のような高精度の内熱式入力補償型の示差走査熱量計を用いることができる。測定方法は、ＡＳＴＭ　Ｄ３４１８−８２に準じて行う。本発明においては、試料を１回昇温させ前履歴をとった後、急冷し、再度温度速度１０℃／ｍｉｎ、温度０〜２００℃の範囲で昇温させたときに測定されるＤＳＣ曲線を用いる。
【００７６】
本発明に用いられる結着樹脂としては、例えばポリスチレン；ポリ−ｐ−クロルスチレン、ポリビニルトルエンの如きスチレン置換体の単重合体；スチレン−ｐ−クロルスチレン共重合体、スチレン−ビニルトルエン共重合体、スチレン−ビニルナフタリン共重合体、スチレン−アクリル酸エステル共重合体、スチレン−メタクリル酸エステル共重合体、スチレン−α−クロルメタクリル酸メチル共重合体、スチレン−アクリロニトリル共重合体、スチレン−ビニルメチルエーテル共重合体、スチレン−ビニルエチルエーテル共重合体、スチレン−ビニルメチルケトン共重合体、スチレン−ブタジエン共重合体、スチレン−イソプレン共重合体、スチレン−アクリロニトリル−インデン共重合体の如きスチレン系共重合体；ポリ塩化ビニル、フェノール樹脂、天然変性フェノール樹脂、天然樹脂変性マレイン酸樹脂、アクリル樹脂、メタクリル樹脂、ポリ酢酸ビニル、シリコーン樹脂、ポリエステル樹脂、ポリウレタン、ポリアミド樹脂、フラン樹脂、エポキシ樹脂、キシレン樹脂、ポリビニルブチラール、テルペン樹脂、クマロンインデン樹脂、石油系樹脂が挙げられる。架橋されたスチレン系樹脂も好ましい結着樹脂である。
【００７７】
スチレン系共重合体のスチレンモノマーに対するコモノマーとしては、アクリル酸、アクリル酸メチル、アクリル酸エチル、アクリル酸ブチル、アクリル酸ドデシル、アクリル酸オクチル、アクリル酸−２−エチルヘキシル、アクリル酸フェニル、メタクリル酸、メタクリル酸メチル、メタクリル酸エチル、メタクリル酸ブチル、メタクリル酸オクチル、アクリロニトリル、メタクリロニトリル、アクリルアミドのような二重結合を有するモノカルボン酸若しくはその置換体；マレイン酸、マレイン酸ブチル、マレイン酸メチル、マレイン酸ジメチルのような二重結合を有するジカルボン酸及びその置換体；塩化ビニル、酢酸ビニル、安息香酸ビニルのようなビニルエステル類；エチレン、プロピレン、ブチレンのようなエチレン系オレフィン類；ビニルメチルケトン、ビニルヘキシルケトンのようなビニルケトン類；ビニルメチルエーテル、ビニルエチルエーテル、ビニルイソブチルエーテルのようなビニルエーテル類；の如きビニル単量体が挙げられる。これらは、単独で、若しくは組み合わせて用いられる。
【００７８】
前記結着樹脂は、架橋剤で架橋されたものであっても良い。架橋剤としては、二個以上の重合可能な二重結合を有する化合物が用いられる。架橋剤としては、例えばジビニルベンゼン、ジビニルナフタレンのような芳香族ジビニル化合物；エチレングリコールジアクリレート、エチレングリコールジメタクリレート、１，３−ブタンジオールジメタクリレートのような二重結合を二個有するカルボン酸エステル；ジビニルアニリン、ジビニルエーテル、ジビニルスルフィド、ジビニルスルホンの如きジビニル化合物；３個以上のビニル基を有する化合物；が挙げられる。これらは単独で、若しくは混合して用いられる。
【００７９】
本発明では、定着時の定着部材からの離型性の向上、定着性の向上の点から、ワックス類（離型剤）をトナー粒子中に含有させることも好ましい。このようなワックス類としては、例えばパラフィンワックス及びその誘導体、マイクロクリスタリンワックス及びその誘導体、フィッシャートロプシュワックス及びその誘導体、ポリオレフィンワックス及びその誘導体、カルナバワックス及びその誘導体が挙げられる。誘導体には、酸化物や、ビニル系モノマーとのブロック共重合体、グラフト変性物が挙げられる。
【００８０】
その他にもワックス類として、長鎖アルコール、長鎖脂肪酸、酸アミド、エステルワックス、ケトン、硬化ヒマシ油及びその誘導体、植物系ワックス、動物系ワックス、鉱物系ワックス、ペトロラクタム等も場合により使用しても良い。
【００８１】
淡色シアントナー、濃色シアントナー、淡色マゼンタトナー及び濃色マゼンタトナーは、公知の方法によって製造することができる。このような製造方法としては、例えば結着樹脂、ワックス、着色剤としての顔料や染料、必要に応じて荷電制御剤の如き添加剤をヘンシェルミキサー、ボールミルの如き混合器により十分混合し、この混合物を加熱ロール、ニーダー、エクストルーダーの如き熱混練機を用いて溶融混練し、顔料等を後から仕込む場合ではこの溶融混練物に顔料等の材料を必要に応じて添加し、この混練物を冷却し、固化後、粉砕、分級を行ってトナー粒子を得る粉砕法が挙げられる。分級工程は、生産効率上、多分割分級機を用いることが好ましい。
【００８２】
さらに、濃淡シアントナー及び濃淡マゼンタトナーを製造する方法としては、例えば特公昭５６−１３９４５号公報等に記載のディスク又は多流体ノズルを用い溶融混合物を空気中に霧化し球状トナーを得る方法や、特公昭３６−１０２３１号公報、特開昭５９−５３８５６号公報、特開昭５９−６１８４２号公報に述べられている懸濁重合方法を用いて直接トナーを生成する方法や、単量体には可溶で得られる重合体が不溶な水系有機溶剤を用い直接トナーを生成する分散重合方法や、水溶性極性重合開始剤存在下で直接重合しトナーを生成するソープフリー重合方法に代表される乳化重合方法等が挙げられる。
【００８３】
濃淡シアントナー及び濃淡マゼンタトナーを製造する方法としては、特には懸濁重合方法が好ましい。さらに一旦得られた重合粒子にさらに単量体を吸着せしめた後、重合開始剤を用い重合せしめるシード重合方法も好適な製造方法である。
【００８４】
さらにスチレン−（メタ）アクリル酸共重合体、スチレン−マレイン酸共重合体、飽和ポリエステル樹脂の如き極性樹脂をトナー粒子に添加せしめることも好ましい。
【００８５】
前記懸濁重合法では、例えば重合性単量体中に低軟化物質からなる離型剤、着色剤、荷電制御剤、重合開始剤その他の添加剤を加え、ホモジナイザー、超音波分散機の如き分散機によって均一に溶解又は分散せしめて重合性単量体組成物を生成し、通常の撹拌機、ホモミキサー又はホモジナイザーにより前記重合性単量体組成物を、分散安定剤を含有する水相中に分散して重合性単量体組成物の液滴粒子を前記水相中に生成し、重合を行い、必要に応じてろ過、洗浄、乾燥、分級等を行う。
【００８６】
前記懸濁重合法では、好ましくは重合性単量体組成物の液滴が所望のトナー粒子のサイズを有するように、撹拌速度及び時間を調整し、造粒する。その後は分散安定剤の作用により、粒子状態が維持され、かつ粒子の沈降が防止される程度の撹拌を行えば良い。重合温度は４０℃以上、一般的には５０〜９０℃、の温度である。
【００８７】
前記濃淡シアントナー及び濃淡マゼンタトナーは、一成分現像剤であっても良いし、二成分現像剤であっても良い。一成分現像剤は、前述のようにして生成されるトナー粒子と無機微粉体等の外添剤とを混合することにより構成される。二成分現像剤は、前述のようにして生成されるトナー粒子と無機微粉体等の外添剤とキャリアとを混合することにより構成される。
【００８８】
前記無機微粉体には、公知のものが用いられる。帯電安定性、現像性、流動性、保存性向上の観点からも、本発明に用いられる無機微粉体は、シリカ微粉体、アルミナ微粉体、チタニア微粉体及びそれらの複酸化物の微粉体の中から選ばれることが好ましい。特にシリカ微粉体が良い。
【００８９】
前記シリカには、ケイ素ハロゲン化物やアルコキシドの蒸気相酸化により生成される乾式シリカ、及びアルコキシド、水ガラス等から製造される湿式シリカが使用可能である。表面及びシリカ微粉体の内部にあるシラノール基が少なく、またＮａ_２Ｏ、ＳＯ_３ ^２−等の製造残滓の少ない乾式シリカの方が好ましい。乾式シリカは、製造工程において、塩化アルミニウム、塩化チタンの如き金属ハロゲン化合物をケイ素ハロゲン化合物と共に用いることによって得られる、シリカと他の金属酸化物の複合微粉体であっても良い。
【００９０】
本発明に用いられる無機微粉体は、ＢＥＴ法で測定した窒素吸着による比表面積が３０ｍ^２／ｇ以上、特に５０〜４００ｍ^２／ｇの範囲のものが良好な結果を与える。無機微粉体の添加量は、トナー粒子１００質量部に対して無機微粉体０．１〜８質量部、好ましくは０．５〜５質量部、さらに好ましくは１．０乃至３．０質量部であることが特に良い。
【００９１】
本発明に用いられる無機微粉体は、一次粒径が３０ｎｍ以下であることが好ましい。
【００９２】
本発明に用いられる無機微粉体は、必要に応じ、疎水化、帯電性制御等の目的でシリコーンワニス、各種変性シリコーンワニス、シリコーンオイル、各種変性シリコーンオイル、シランカップリング剤、官能基を有するシランカップリング剤、その他の有機ケイ素化合物、有機チタン化合物の如き処理剤で、処理されていることが好ましい。処理剤は二種以上併用しても良い。
【００９３】
トナーが高い帯電量を維持し、低消費量及び高転写率を達成するためには、無機微粉体は少なくともシリコーンオイルで処理されることがさらに好ましい。
【００９４】
前記無機微粉体は、特定のカップリング剤を水存在下で加水分解しながら処理した無機微粉体であることが好ましい。水中では均質な疎水化処理が行え、粒子同士の合一もなく、また処理による粒子間の帯電反発作用が働き、無機微粒子はほぼ一次粒子の状態で表面処理され、トナーの帯電の安定化、流動性付与の点で、極めて有効である。このような好ましい無機微粉体としては、例えば特定のカップリング剤を水存在下で加水分解しながら処理し、平均粒径が０．０１〜０．２μｍであり、疎水化度が２０〜９８％であり、かつ４００ｎｍにおける光透過率が４０％以上であるシリカ、酸化チタンあるいはアルミナが挙げられる。
【００９５】
カップリング剤を水存在下で加水分解しながら表面を処理する方法では、無機微粒子を一次粒子に分散させるための機械的な力を加えるため、クロロシラン類や、シラザン類のようにガス化するようなカップリング剤を使用する必要もなく、さらに、粒子同士が合一して使用できなかった高粘性のカップリング剤あるいはシリコーンオイルの併用も可能である。
【００９６】
カップリング剤としては、シランカップリング剤又はチタンカップリング剤が挙げられる。特に好ましく用いられるのはシランカップリング剤であり、下記一般式で示されるものが挙げられる。
ＲｍＳｉＹｎ　　・・・（化１）
［式中、Ｒはアルコオキシ基を示し、ｍは１〜３の整数を示し、Ｙはアルキル基、ビニル基、グリシドキシ基、メタクリル基の如き炭化水素基を示し、ｎは１〜３の整数を示す。］
このようなシランカップリング剤としては、例えばビニルトリメトキシシラン、ビニルトリエトキシシラン、γ−メタクリルオキシプロピルトリメトキシシラン、ビニルトリアセトキシシラン、メチルトリメトキシシラン、メチルトリエトキシシラン、イソブチルトリメトキシシラン、ジメチルジメトキシシラン、ジメチルジエトキシシラン、トリメチルメトキシシラン、ヒドロキシプロピルトリメトキシシラン、フェニルトリメトキシシラン、ｎ−ヘキサデシルトリメトキシシラン、ｎ−オクタデシルトリメトキシシランが挙げられる。
【００９７】
より好ましくは、次式で示されるトリアルコキシアルキルシランカップリング剤が好ましい。
Ｃ_ａＨ_２ａ＋１−Ｓｉ（ＯＣ_ｂＨ_２ｂ＋１）_３　　・・・（化２）
［式中、ａは４〜１２の整数を示し、ｂは１〜３の整数を示す。］
上記式においてａが４より小さいと、処理は容易となるが疎水性が低下することがある。ａが１２より大きいと疎水性は十分になるが、粒子同士が合一しやすい。ｂは３より大きいと反応性が低下することがある。ａは４〜１２、好ましくは４〜８であり、ｂは１〜３、好ましくは１又は２である。
【００９８】
前記シランカップリング剤の処理量は、無機微粉体１００質量部に対して１〜５０質量部、好ましくは３〜４０質量部が良い。疎水化度は２０〜９８％、より好ましくは３０〜９０％、より好ましくは４０〜８０％が良い。疎水化度は２０％より小さいと、高湿下での長期放置による帯電量が低下しやすく、疎水化度が９８％を超えると、低湿下でのトナーがチャージアップしやすい。
【００９９】
疎水化された無機微粉体の粒径は、トナー粒子の流動性向上の点から０．０１〜０．２μｍが良い。粒径が０．２μｍより大きいと、トナーの帯電の均一性が低下し、結果としてトナー飛散やカブリが生じやすい。０．０１μｍより小さいと、トナー粒子表面に埋め込まれやすくなり、トナー劣化が生じやすく、耐久性が低下しやすい。この添加剤の粒径とは、電子顕微鏡におけるトナー（例えば２万倍）の表面観察により求めたその平均粒径を意味する。
【０１００】
本発明では、転写性及びクリーニング性向上のために、前記無機微粉体に加えて、さらに一次粒径が３０ｎｍを超える（好ましくは比表面積が５０ｍ^２／ｇ未満）、より好ましくは、５０ｎｍ以上（好ましくは比表面積が３０ｍ^２／ｇ未満）の無機又は有機の球状に近い微粒子をさらに添加することも好ましい形態の一つである。このような球状に近い微粒子としては、例えば球状シリカ粒子、球状ポリメチルシルセスキオキサン粒子、球状樹脂粒子が好ましくは挙げられる。
【０１０１】
本発明では、実質的な悪影響を与えない範囲内でさらに他の添加剤を使用しても良い。このような他の添加剤としては、例えばフッ素樹脂粉末、ステアリン酸亜鉛粉末、ステアリン酸カルシウム粒子、ポリフッ化ビニリデン粉末の如き滑剤粉末；酸化セリウム粉末、炭化ケイ素粉末、チタン酸ストロンチウム粉末の如き研磨剤；酸化アルミニウム粉末の如き流動性付与剤；ケーキング防止剤；カーボンブラック粉末、酸化亜鉛粉末、酸化スズ粉末の如き導電性付与剤；トナー粒子と逆極性の有機微粒子及び無機微粒子が挙げられる。
【０１０２】
前記添加剤としては、トナー粒子と混合した時の耐久性の点から、トナー粒子の重量平均粒子径の１／１０以下の粒径であることが好ましい。この添加剤の粒径とは、電子顕微鏡におけるトナー粒子（例えば２万倍）の表面観察により求めたその平均粒径を意味する。
【０１０３】
これら添加剤は、トナー粒子１００質量部に対し、０．０１〜１０質量部用いられることが好ましく、０．０５〜５質量部用いられることがより好ましい。添加剤は、単独で用いても良いし、複数種を併用しても良い。添加剤は、疎水化処理を行ったものであることがより好ましい。
【０１０４】
トナー粒子表面の外添剤被覆率が５〜９９％であることが好ましく、１０〜９９％であることがより好ましい。トナー粒子表面の外添剤被覆率は、日立製作所製ＦＥ−ＳＥＭ（Ｓ−８００）を用いトナー粒子像（例えば、２万倍）を１００個無作為にサンプリングし、その画像情報はインターフェースを介してニレコ社製画像解析装置（Ｌｕｚｅｘ３）を導入し解析を行い算出することにより求めることができる。
【０１０５】
前記キャリアには、磁性体からなるキャリア、磁性体の表面を樹脂で被覆した構成のキャリア、及び樹脂粒子中に磁性体を分散させた構成のキャリア等、公知のキャリアを用いることができる。前記磁性体には、酸化鉄を主成分とする公知の磁性体を用いることができ、前記樹脂には、例えば前述した結着樹脂を用いることができる。
【０１０６】
なお、後述する本発明の画像形成方法において、フルカラー画像の形成で使用されるイエロートナー、ブラックトナー、或いは、濃色及び淡色のシアントナーと組み合わせて用いる場合のマゼンタトナー、或いは、濃色及び淡色のマゼンタトナーと組み合わせて用いる場合のシアントナーについては、着色剤が異なる以外は、前述の結着樹脂や荷電制御剤等を用いることができる。尚、当然、濃色及び淡色のシアントナーと濃色及び淡色のマゼンタトナーと組み合わせて用いても良い。
【０１０７】
イエロー着色剤としては、縮合アゾ化合物、イソインドリノン化合物、アンスラキノン化合物、アゾ金属錯体、メチン化合物、アリルアミド化合物に代表される化合物が挙げられる。具体的には、Ｃ．Ｉ．ピグメントイエロー１２、１３、１４、１５、１７、６２、７４、８３、９３、９４、９５、９７、１０９、１１０、１１１、１２０、１２７、１２８、１２９、１４７、１６８、１７４、１７６、１８０、１８１、１９１が好適に用いられる。
【０１０８】
マゼンタ着色剤としては、濃色及び淡色マゼンタトナーに用いることができるものに加えて、Ｃ．Ｉ．ピグメントレッド２、３、５、６、７、２３、８１：１、１６６、１６９、１８４、１８５、２０６を用いることもできる。
【０１０９】
黒色着色剤としては、カーボンブラックや、前記イエロー、マゼンタ、及び前述したシアンの着色剤を用いて黒色に調色されたものが挙げられる。
【０１１０】
これらの着色剤は、単独又は混合しさらには固溶体の状態で用いることができる。着色剤は、色相角、彩度、明度、耐候性、ＯＨＰ透明性、トナー粒子中への分散性の点から選択される。着色剤の添加量は、着色剤の種類によって異なるが、好ましくは結着樹脂１００質量部に対し１〜２０質量部である。
【０１１１】
黒色着色剤としては、公知の磁性体を用いることができる。このような磁性体としては、鉄、コバルト、ニッケル、銅、マグネシウム、マンガン、アルミニウム、ケイ素などの元素を含む金属酸化物が挙げられる。中でも四三酸化鉄、γ−酸化鉄の如き酸化鉄を主成分とするものが好ましい。磁性体は、トナーの帯電性コントロールの点からケイ素元素又はアルミニウム元素の如き金属元素を含有していてもよい。磁性体は、窒素吸着法によるＢＥＴ比表面積が２〜３０ｍ^２／ｇ、特に３〜２８ｍ^２／ｇであることが好ましく、モース硬度が５〜７であることが好ましい。
【０１１２】
磁性体の形状としては、８面体、６面体、球体、針状、鱗片状などが挙げられる。８面体、６面体、球体の如く異方性の少ないものが画像濃度を高める上で好ましい。磁性体の平均粒径としては０．０５〜１．０μｍが好ましく、さらに好ましくは０．１〜０．６μｍであり、さらには０．１〜０．４μｍが好ましい。
【０１１３】
磁性体の添加量は、結着樹脂１００質量部に対し３０〜２００質量部であることが好ましく、４０〜２００質量部であることがより好ましく、５０〜１５０質量部であることがより一層好ましい。３０質量部未満ではトナー搬送に磁気力を用いる現像器においては、搬送性が低下し、現像剤担持体上の現像剤層にむらが生じ画像むらとなる傾向であり、さらに磁性トナーのトリボの上昇に起因する画像濃度の低下が生じ易い傾向にある。一方、２００質量部を超えると定着性に問題が生ずる傾向にある。
【０１１４】
次に本発明に用いられるトナーの製造方法に関して説明する。
【０１１５】
本発明では、トナー粒子の一部又は全体が重合法により形成されたトナーを用いることにより、発明の効果を高めることができる。特に、トナー粒子表面の部分を重合法により形成されたトナー粒子については、表面がかなり平滑化されたものを得ることができる。
【０１１６】
コア／シェル構造のシェル部分を重合により形成したトナー粒子を用いることは、優れた定着性を損なうことなく耐ブロッキング性を向上させることができ、コア部を有しないようなバルクとしての重合トナーに比較して、重合工程後の後処理工程において、残存モノマーの除去が容易に行える利点がある。
【０１１７】
コア部の主たる成分としては低軟化点物質（前述したワックス類又は離型剤）が好ましく、ＡＳＴＭ　Ｄ３４１８−８に準拠して測定された吸熱ピークの主体極大ピーク値が、４０〜９０℃を示す化合物が好ましい。極大ピークが４０℃未満であると低軟化点物質の自己凝集力が弱くなり、結果として耐高温オフセット性が低下する。一方極大ピークが、９０℃を超えると定着温度が高くなる。
【０１１８】
低軟化点物質の極大ピーク値の温度の測定には、例えばパーキンエレマー社製ＤＳＣ−７を用いる。装置検出部の温度補正はインジウムと亜鉛の融点を用い、熱量の補正についてはインジウム融解熱を用いる。サンプルはアルミニウム製パンを用い対照用に空パンをセットし、昇温速度１０℃／ｍｉｎ．で測定を行う。
【０１１９】
低軟化点物質としては、前述した如きワックスを用いることができ、パラフィンワックス、ポリオレフィンワックス、フィッシャートロピッシュワックス、アミドワックス、高級脂肪酸、エステルワックス及びこれらの誘導体又はこれらのグラフト／ブロック化合物が挙げられる。
【０１２０】
低軟化点物質はトナー粒子中へ結着樹脂１００質量部当たり５〜３０質量部添加することが好ましい。５質量部未満の添加では先に述べた残存モノマーの除去に負担がかかり、また３０質量部を超える場合は、重合法による製造においても造粒時にトナー粒子同士の合一が起きやすく、粒度分布の広いものが生成しやすい。
【０１２１】
コア／シェル構造においてシェル部を構成する外殻樹脂としては、スチレン−（メタ）アクリル共重合体、ポリエステル樹脂、エポキシ樹脂、スチレン−ブタジエン共重合体が挙げられる。重合法による直接トナーを得る方法においては、スチレン；ｏ−（ｍ−、ｐ−）メチルスチレン、ｍ−（ｐ−）エチルスチレンの如きスチレン系単量体；（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸プロピル、（メタ）アクリル酸ブチル、（メタ）アクリル酸オクチル、（メタ）アクリル酸ドデシル、（メタ）アクリル酸ステアリル、（メタ）アクリル酸ベヘニル、（メタ）アクリル酸−２−エチルヘキシル、（メタ）アクリル酸ジメチルアミノエチル、（メタ）アクリル酸ジエチルアミノエチルの如き（メタ）アクリル酸エステル系単量体；ブタジエン、イソプレン、シクロヘキセン、（メタ）アクリロニトリル、アクリル酸アミドの如きエン系単量体が好ましく用いられる。
【０１２２】
これらは、単独で用いられるか、又は出版物ポリマーハンドブック第２版ＩＩＩ−Ｐ１３９〜１９２（Ｊｏｈｎ　Ｗｉｌｅｙ＆Ｓｏｎｓ社製）に記載の理論ガラス転移温度（Ｔｇ）が、４０〜７５℃を示すように単量体を適宜混合して重合に用いられる。理論ガラス転移温度が４０℃未満の場合には、トナーの保存安定性や現像剤の耐久安定性の面から問題が生じ、一方７５℃を超える場合は定着点の上昇をもたらし、特にフルカラー画像形成用トナーの場合においては、各色トナーの混色性が低下し、色再現性が低下することがある。さらにＯＨＰ画像の透明性が著しく低下することがある。
【０１２３】
外殻樹脂の分子量は、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）により測定される。具体的なＧＰＣの測定方法としては、予めトナーをソックスレー抽出器を用いトルエン溶剤で２０時間抽出を行った後、ロータリーエバポレーターでトルエンを留去せしめ、さらに低軟化点物質は溶解するが外殻樹脂は溶解し得ない有機溶剤、例えばクロロホルム等、を加え十分洗浄を行った後、ＴＨＦ（テトラヒドロフラン）に可溶した溶液をポア径が０．３μｍの耐溶剤性メンブランフィルターでろ過したサンプルを、例えばウォーターズ社製１５０Ｃを用いて測定する方法が挙げられる。このような測定におけるカラム構成は、昭和電工製Ａ−８０１、８０２、８０３、８０４、８０５、８０６、８０７を連結した構成が挙げられ、標準ポリスチレン樹脂の検量線を用い分子量分布が得られる。外殻樹脂は、数平均分子量（Ｍｎ）が５０００〜１００００００であり、重量平均分子量（Ｍｗ）と数平均分子量（Ｍｎ）の比（Ｍｗ／Ｍｎ）が２〜１００であることが、本発明には好ましい。
【０１２４】
コア／シェル構造を有するトナー粒子を製造する場合、外殻樹脂中に低軟化点物質を良好に内包化せしめるため、外殻樹脂の他にさらに極性樹脂を添加せしめることが特に好ましい。極性樹脂としては、スチレンと（メタ）アクリル酸の共重合体、マレイン酸共重合体、飽和ポリエステル樹脂、エポキシ樹脂が好ましく用いられる。該極性樹脂は、外殻樹脂又は単量体と反応しうる不飽和基を分子中に含まないものが特に好ましい。仮に不飽和基を有する極性樹脂を含む場合においては、外殻樹脂層を形成する単量体と架橋反応が起き、特に、フルカラー画像形成用トナーとしては、極めて高分子量になり四色トナーの混色には不利となり好ましくない。
【０１２５】
本発明に用いられるトナーには、トナー粒子の表面にさらに最外殻樹脂層を設けても良く、前記極性樹脂を最外殻樹脂層として用いてもよい。
【０１２６】
前記最外殻樹脂層のガラス転移温度は、耐ブロッキング性のさらなる向上のため、前記外殻樹脂層のガラス転移温度以上に設計されること、さらに定着性を損なわない程度に架橋されていることが好ましい。最外殻樹脂層には、帯電性向上のため極性樹脂や荷電制御剤が含有されていることが好ましい。
【０１２７】
前記最外殻層を設ける方法としては、特に限定されるものではないが、例えば（１）重合反応後半、又は終了後、反応系中に必要に応じて、極性樹脂、荷電制御剤、架橋剤等を溶解、分散したモノマーを添加し重合粒子に吸着させ、重合開始剤を添加し重合を行う方法や、（２）必要に応じて、極性樹脂、荷電制御剤、架橋剤等を含有したモノマーからなる乳化重合粒子又はソープフリー重合粒子を反応系中に添加し、重合粒子表面に凝集、必要に応じて熱等により固着させる方法や、（３）必要に応じて、極性樹脂、荷電制御剤、架橋剤等を含有したモノマーからなる乳化重合粒子又はソープフリー重合粒子を乾式で機械的にトナー粒子表面に固着させる方法、等が挙げられる。
【０１２８】
本発明では、特に比較的容易に粒度分布がシャープで４〜８μｍ粒径の微粒子トナーが得られる常圧下での、又は、加圧下での懸濁重合方法が特に好ましい。低軟化点物質を内包化せしめる具体的方法としては、水系媒体中での材料の極性を主要単量体より低軟化点物質の方を小さく設定し、さらに少量の極性の大きな樹脂又は単量体を添加せしめ、重合する方法が挙げられる。このような方法によれば、低軟化点物質を外殻樹脂で被覆した所謂コア／シェル構造を有するトナーを得ることができる。
【０１２９】
前述の製造方法におけるトナーの粒度分布制御や粒径は、難水溶性の無機塩や保護コロイド作用をする分散剤の種類や添加量を変える方法や機械的装置条件（例えばローター周速、パス回数、撹拌羽根形状の撹拌条件や容器形状）又は、水溶液中での固形分濃度等によって制御することができる。
【０１３０】
トナー粒子の断層面を測定する具体的方法としては、常温硬化性のエポキシ樹脂中にトナー粒子を十分分散させた後、温度４０℃の雰囲気中で２日間硬化させ、得られた硬化物を四三酸化ルテニウム、必要により四三酸化オスミウムを併用し染色を施した後、ダイヤモンド歯を備えたミクロトームを用い薄片状のサンプルを切り出し透過電子顕微鏡（ＴＥＭ）を用いトナーの断層形態を測定する方法が挙げられる。前記断層面の測定では、低軟化点物質と外殻を構成する樹脂との若干の結晶化度の違いを利用して材料間のコントラストを付けるため、四三酸化ルテニウム染色法を用いることが好ましい。
【０１３１】
次に、本発明の画像形成方法について説明する。
【０１３２】
本発明の画像形成方法は、淡色シアントナー画像と濃色シアントナー画像の重ね合わせ、及び／又は淡色マゼンタトナー画像と濃色マゼンタトナー画像の重ね合わせによってトナー画像を形成する方法であり、前述した淡色シアントナー、濃色シアントナー、淡色マゼンタトナー及び濃色マゼンタトナーを用いることを特徴とする。
【０１３３】
このような画像形成方法によれば、低濃度領域から高濃度領域まで、粒状感、ガサつきを低減し、より高品質なシアン画像、若しくはマゼンタ画像を少なくとも形成することができ、ひいては高品質なフルカラー画像を形成することができる。
【０１３４】
ｉ）静電荷像を形成する工程として、シアントナーで現像されるシアン用静電荷像を形成する工程と、マゼンタトナーで現像されるマゼンタ用静電荷像を形成する工程と、イエロートナーで現像されるイエロー用静電荷像を形成する工程と、ブラックトナーで現像されるブラック用静電荷像を形成する工程とを含み、ｉｉ）トナー画像を形成する工程として、シアン用静電荷像をシアントナーで現像してシアントナー画像を形成する工程と、マゼンタ用静電荷像をマゼンタトナーで現像してマゼンタトナー画像を形成する工程と、イエロー用静電荷像をイエロートナーで現像してイエロートナー画像を形成する工程と、ブラック用静電荷像をブラックトナーで現像してブラックトナー画像を形成する工程とを含み、ｉｉｉ）転写する工程として、シアントナー画像とマゼンタトナー画像とイエロートナー画像とブラックトナー画像とを転写材に転写して、フルカラートナー画像を転写材に形成する工程を含む画像形成方法において、シアントナー及び／又はマゼンタトナーを用いる工程として、濃色トナーを用いる工程及び淡色トナーを用いる工程とに分けた場合に、シアン画像或いはマゼンタ画像に起因する粒状感やガサつきを低減することができ、高品質のフルカラー画像を得ることができる。
【０１３５】
前記静電荷像を形成する工程は、本画像形成方法において使用されるトナーに対応した静電荷像をそれぞれ別個に形成する工程である。フルカラー画像形成における各トナーに対応した静電荷像の形成については、公知の方法によって形成することができる。
【０１３６】
前記静電荷像を形成する工程は、淡色シアントナー又は濃色シアントナーで現像される第一の静電荷像を形成する工程と、もう一方のシアントナーで現像される第二の静電荷像を形成する工程とを含む。或いは、淡色マゼンタトナー又は濃色マゼンタトナーで現像される第一の静電荷像を形成する工程と、もう一方のマゼンタトナーで現像される第二の静電荷像を形成する工程とを含む。
【０１３７】
出力画像中のシアン画像は、他色の画像と同様に、入力されるシアン画像の画像濃度、輝度等の入力信号が、画像形成における階調性等に応じて適切な演算や補正が行われて出力信号に変換され、この出力信号に基づき形成される。本発明では、淡色シアントナーの出力信号の強度及び濃色シアントナーの出力信号の強度を入力信号の強度に対応して予め設定しておき、この設定に基づき各シアントナーの出力信号中における強度を決定し、第一の静電荷像及び第二の静電荷像を形成する。また、淡色マゼンタトナー及び濃色マゼンタトナーを用いる場合も同様である。
【０１３８】
前記出力信号の強度の設定については、人間の視覚特性等、単純に数値化することが困難な要素を含むため一概には言えないが、例えば、図１５に示すように、入力信号の強度が小さい領域では淡色シアントナーの出力信号の強度を大きくし、入力信号の強度が大きくなるにつれて濃色シアントナーの出力信号の強度を大きくするようにする設定を例示することができる。
【０１３９】
前記トナー画像を形成する工程は、静電荷像担持体に形成された静電荷像を、これに対応するトナーで現像してトナー画像を形成する工程である。トナー画像を形成する工程は、使用されるトナーの種類等に応じて公知の方法で行われ、適宜選択される現像装置によって行われる。
【０１４０】
前記転写する工程は、静電荷像担持体に形成された各トナー画像を、静電荷像担持体から転写材に転写して、形成された全てのトナー画像が重ねられた状態のトナー画像を転写材に形成する工程である。トナー画像の転写材への転写は、特に限定されず、公知の方法で行うことができる。トナー画像の転写材への転写は、静電荷像担持体から直接、転写材に転写する方法であっても良いし、静電荷像担持体から中間転写体を介して転写材に転写する方法であっても良い。静電荷像担持体から中間転写体を介して転写材に転写する方法では、中間転写体に一次転写されたトナー画像と、その後に静電荷像担持体から転写されるトナー画像とが重なるように転写される。
【０１４１】
前記転写材上のトナー画像は、公知の加熱加圧定着装置を用いてトナー画像を転写材に定着される。定着工程としては、加熱加圧工程が好ましい。
【０１４２】
本発明では、前述した工程の他にも、転写後の静電荷像担持体に残存するトナーを静電荷像担持体から除去するクリーニング工程等、種々の工程を含む方法であっても良い。また、本発明では、一つの静電荷像担持体にそれぞれのトナーに対応する静電荷像を形成し、トナーごとに静電荷像の形成から転写までを繰り返し行う画像形成方法であっても良いし、それぞれのトナーに対応する複数の静電荷像担持体を用いて、静電荷像担持体ごとにトナーごとの静電荷像の形成から転写までを個別に行う画像形成方法であっても良い。また、本発明では、静電荷像の形成、トナー画像の形成、及び転写材への転写について、各トナー間における順序は特に限定されない。
【０１４３】
本発明に用いられる静電荷像担持体は、静電荷像担持体表面の水に対する接触角を８５度以上（好ましくは９０度以上）とすることが良い。水に対する接触角が８５度以上であるとトナー像の転写率が向上し、トナーのフィルミングも生じにくい。静電荷像担持体表面の水に対する接触角は、例えば滴下式の接触角計（協和界面科学（株）製）を用いて測定することができる。
【０１４４】
本発明に用いられる静電荷像担持体の好ましい態様の例を以下に説明する。本発明に用いられる静電荷像担持体は、公知のごとく、導電性基体と導電性基体上に形成される感光層と、必要に応じて前記保護層（表面層）とによって構成される。感光層は、電荷発生層や電荷輸送層等、それぞれに特有の機能を有する層を積層して構成したものであっても良い。
【０１４５】
導電性基体を形成する材料としては、アルミニウム、ステンレスの如き金属；アルミニウム合金、酸化インジウム−酸化錫合金の如き合金の被膜層を有するプラスチック；導電性粒子を含浸させた紙、プラスチック；導電性ポリマーを有するプラスチックが挙げられる。基体としては円筒状シリンダー及びフィルムが用いられる。
【０１４６】
これら導電性基体上には、感光層の接着性向上、塗工性改良、基体の保護、基体上の欠陥の被覆、基体からの電荷注入性改良、感光層の電気的破壊に対する保護を目的として下引き層を設けても良い。
【０１４７】
下引き層は、ポリビニルアルコール、ポリ−Ｎ−ビニルイミダゾール、ポリエチレンオキシド、エチルセルロース、メチルセルロース、ニトロセルロース、エチレン−アクリル酸コポリマー、ポリビニルブチラール、フェノール樹脂、カゼイン、ポリアミド、共重合ナイロン、ニカワ、ゼラチン、ポリウレタン、酸化アルミニウムの如き材料によって形成される。その膜厚は通常０．１〜１０μｍ、好ましくは０．１〜３μｍである。
【０１４８】
電荷発生層は、アゾ系顔料、フタロシアニン系顔料、インジゴ系顔料、ペリレン系顔料、多環キノン系顔料、スクワリリウム色素、ピリリウム塩類、チオピリリウム塩類、トリフェニルメタン系色素の如き有機材料；セレン、非晶質シリコンの如き無機物質；からなる電荷発生物質を、適当な結着剤に分散し塗工あるいは蒸着により形成される。
【０１４９】
結着剤としては、広範囲な結着性樹脂から選択できる。例えば、ポリカーボネート樹脂、ポリエステル樹脂、ポリビニルブチラール樹脂、ポリスチレン樹脂、アクリル樹脂、メタクリル樹脂、フェノール樹脂、シリコーン樹脂、エポキシ樹脂、酢酸ビニル樹脂が挙げられる。電荷発生層中に含有される結着剤の量は８０質量％以下、好ましくは０〜４０質量％が良い。電荷発生層の膜厚は５μｍ以下、特には０．０５〜２μｍが好ましい。
【０１５０】
電荷輸送層は、電界の存在下で電荷発生層から電荷キャリアを受け取り、これを輸送する機能を有している。電荷輸送層は、電荷輸送物質を必要に応じて結着樹脂と共に溶剤中に溶解し、塗工することによって形成される。その膜厚は一般的には５〜４０μｍである。
【０１５１】
電荷輸送物質としては、主鎖又は側鎖にビフェニレン、アントラセン、ピレン、フェナントレンの如き構造を有する多環芳香族化合物；インドール、カルバゾール、オキサジアゾール、ピラゾリンの如き含窒素環式化合物；ヒドラゾン化合物；スチリル化合物；セレン、セレン−テルル、非晶質シリコン、硫化カドニウムの如き無機化合物が挙げられる。
【０１５２】
これら電荷輸送物質を分散させる結着樹脂としては、ポリカーボネート樹脂、ポリエステル樹脂、ポリメタクリル酸エステル、ポリスチレン樹脂、アクリル樹脂、ポリアミド樹脂の如き樹脂；ポリ−Ｎ−ビニルカルバゾール、ポリビニルアントラセンの如き有機光導電性ポリマーが挙げられる。
【０１５３】
さらに表面層として保護層を設けてもよい。保護層の樹脂としては、ポリエステル、ポリカーボネート、アクリル樹脂、エポキシ樹脂、フェノール樹脂、あるいはこれらの樹脂を硬化剤で硬化させたものが挙げられる。これらは、単独あるいは二種以上組み合わされて用いられる。
【０１５４】
保護層の樹脂中に導電性微粒子を分散してもよい。導電性微粒子の例としては、金属又は金属酸化物の微粒子が挙げられる。好ましくは、酸化亜鉛、酸化チタン、酸化スズ、酸化アンチモン、酸化インジウム、酸化ビスマス、酸化スズ被膜酸化チタン、スズ被膜酸化インジウム、アンチモン被膜酸化スズ、酸化ジルコニウムの如き材料の微粒子がある。これらは単独で用いても二種以上を混合して用いても良い。
【０１５５】
一般的に保護層に導電性微粒子を分散させる場合、導電性微粒子による入射光の散乱を防ぐために、入射光の波長よりも導電性微粒子の粒径の方が小さいことが好ましい。保護層に分散される導電性微粒子の粒径としては０．５μｍ以下であることが好ましい。保護層中での含有量は、保護層総質量に対して２〜９０質量％が好ましく、５〜８０質量％がより好ましい。保護層の膜厚は、０．１〜１０μｍが好ましく、１〜７μｍがより好ましい。
【０１５６】
表面層の塗工は、樹脂分散液をスプレーコーティング、ビームコーティングあるいは浸透コーティングすることによって行うことができる。
【０１５７】
本発明において一成分現像方法を用いる場合には、高画質を得るためにトナー担持体上にトナー担持体−静電荷像担持体の最近接距離（Ｓ−Ｄ間）よりも小さい層厚でトナーを塗布し、交番電界を印加して現像を行う現像工程で現像されることが好ましい。
【０１５８】
本発明に使用されるトナー担持体の表面粗さは、ＪＩＳ中心線平均粗さ（Ｒａ）で０．２〜３．５μｍの範囲にあることが好ましい。Ｒａが０．２μｍ未満ではトナー担持体上の帯電量が高くなりやすく、現像性が低下しやすい。Ｒａが３．５μｍを超えると、トナー担持体上のトナーコート層にむらが生じやすい。前記表面粗さは、０．５〜３．０μｍであることがより好ましい。
【０１５９】
さらに本発明に用いられるトナーは、高い帯電能力を有するために、現像に際してはトナーの総帯電量をコントロールすることが好ましい。トナー担持体の表面は、導電性微粒子や滑剤を分散した樹脂層で被覆されていることが好ましい。
【０１６０】
トナー担持体表面を被覆する樹脂層に含有される導電性微粒子としては、カーボンブラック、グラファイト、導電性酸化亜鉛の如き導電性金属酸化物及び金属複酸化物が挙げられる。これらは単独若しくは二つ以上好ましく用いられる。該導電性微粒子が分散される樹脂としては、フェノール系樹脂、エポキシ系樹脂、ポリアミド系樹脂、ポリエステル系樹脂、ポリカーボネート系樹脂、ポリオレフィン系樹脂、シリコーン系樹脂、フッ素系樹脂、スチレン系樹脂、アクリル系樹脂の如き樹脂が用いられる。特に熱硬化性若しくは光硬化性の樹脂が好ましい。
【０１６１】
トナーは、トナー担持体上のトナーを規制する部材がトナーを介してトナー担持体に当接されている弾性部材によって規制されることが、トナーを均一帯電させる点から特に好ましい。本発明においては、オゾンが発生しないように帯電部材及び転写部材が静電荷像担持体に当接されていることが、環境保全上より好ましい。
【０１６２】
次に、図１０を参照しながら本発明の画像形成方法をより具体的に説明する。図１０において、Ａはプリンター部、Ｂはこのプリンター部Ａの上に搭載された画像読み取り部（イメージスキャナ）である。
【０１６３】
画像読み取り部Ｂにおいて、２０は固定の原稿台ガラスであり、この原稿台ガラス２０の上面に原稿Ｇを、複写すべき面を下側にして載置し、その上に不図示の原稿板を被せてセットする。２１は原稿照射用ランプ２１ａ、短焦点レンズアレイ２１ｂ、ＣＣＤセンサ２１ｃ等を配置した画像読み取りユニットである。
【０１６４】
この画像読み取りユニット２１は、不図示のコピーボタンが押されることで、原稿台ガラス２０の下側において、この原稿台ガラス２０の左辺側のホームポジションから右辺側にガラス下面に沿って往動駆動され、所定の往復終点に達すると復動駆動されて、始めのホームポジションに戻される。
【０１６５】
画像読み取りユニット２１の往動駆動過程において、原稿台ガラス２０上に載置された原稿Ｇの下向き画像面が原稿照射用ランプ２１ａにより左辺側から右辺側にかけて順次照明走査され、その照明走査光の原稿面反射光が短焦点レンズアレイ２１ｂによってＣＣＤセンサ２１ｃに結像入射する。
【０１６６】
ＣＣＤセンサ２１ｃは、不図示の受光部、転送部、出力部より構成されており、受光部において光信号が電荷信号に変えられて、電荷信号は転送部でクロックパルスに同期して順次出力部へ転送され、出力部において電荷信号を電圧信号に変換し、増幅、低インピーダンス化して出力する。このようにして得られたアナログ信号を周知の画像処理によりデジタル信号に変換してプリンター部Ａに出力する。即ち、画像読み取り部Ｂにより、原稿Ｇの画像情報が時系列電気デジタル画素信号（画像信号）として光電読み取りされる。
【０１６７】
図１２に画像処理のブロック図を示す。同図において、ＣＣＤセンサ２１ｃから出力された画像信号は、アナログ信号処理部５１に入力されてゲインやオフセットが調整された後、Ａ／Ｄ変換部５２で各色成分ごとに、例えば、８ビット（０〜２５５レベル：２５６階調）のＲＧＢデジタル信号に変換され、シェーディング補正部５３において、各色ごとに基準白色板（不図示）を読み取った信号を用いて、一列に並んだＣＣＤのセンサセル群におけるセンサの一つ一つの感度バラツキをなくすために、一つ一つのＣＣＤセンサセルに対応させてゲインを最適化してかける公知のシェーディング補正が施される。
【０１６８】
ラインディレイ部５４は、シェーディング補正部５３から出力された画像信号に含まれている空間的ずれを補正する。この空間的ずれは、ＣＣＤセンサ２１ｃの各ラインセンサが、副走査方向に、互いに所定の距離を隔てて配置されていることにより生じたものである。空間的ずれの補正は、具体的には、Ｂ（ブルー）色成分信号を基準として、Ｒ（レッド）及びＧ（グリーン）の各色成分信号を副走査方向にライン遅延し、３つの色成分信号の位相を同期させる。
【０１６９】
入力マスキング部５５は、ラインディレイ部５４から出力された画像信号の色空間を、下記式に示すマトリクス演算により、ＮＴＳＣの標準色空間に変換する。つまり、ＣＣＤセンサ２１ｃから出力された各色成分信号の色空間は、各色成分のフィルターの分光特性で決まっているが、入力マスキング部５５は、これをＮＴＳＣの標準色空間に変換するものである。
【０１７０】
【数６】

【０１７１】
ＬＯＧ変換部５６は、例えば、ＲＯＭなどからなるルックアップテーブル（ＬＵＴ）で構成され、入力マスキング部５５から出力されたＲＧＢ輝度信号をＣＭＹ濃度信号に変換する。ライン遅延メモリ５７は、黒文字判定部（不図示）が入力マスキング部５５の出力から制御信号ＵＣＲ、ＦＩＬＴＥＲ、ＳＥＮなどを生成する期間（ライン遅延）分、ＬＯＧ変換部５６から出力された画像信号を遅延する。
【０１７２】
マスキング・ＵＣＲ部５８は、ライン遅延メモリ５７から出力された画像信号から黒成分信号Ｋを抽出し、さらに、プリンター部の記録色材の色濁りを補正するマトリクス演算を、ＹＭＣＫが信号に施して、リーダ部の各読み取り動作ごとにＭ、Ｃ、Ｙ、Ｋ順に、例えば８ビットの色成分画像信号を出力する。なお、マトリクス演算に使用するマトリクス係数は、ＣＰＵ（不図示）によって設定されるものである。
【０１７３】
次に、得られたデータ８ビットの色成分画像信号Ｄａｔａに基づき、濃ドットと淡ドットの記録率Ｒｎ、Ｒｔを、図１５を参照して決定する処理を行う。例えば入力した階調データＤａｔａが、１００／２５５であれば、淡ドットの記録率Ｒｔは２５０／２５５、濃ドットの記録率Ｒｎは４０／２５５として決定される。なお、記録率は１００パーセントを２５５とする絶対値で示してある。
【０１７４】
γ補正部５９は、画像信号をプリンター部の理想的な階調特性に合わせるために、マスキング・ＵＣＲ部５８から出力された画像信号に濃度補正を施す。出力フィルター（空間フィルター処理部）６０は、ＣＰＵからの制御信号に従って、γ補正部５９から出力された画像信号にエッジ強調又はスムージング処理を施す。
【０１７５】
ＬＵＴ６１は、原画像の濃度と出力画像の濃度とを一致させるためのもので、例えばＲＡＭなどで構成され、その変換テーブルは、ＣＰＵによって設定されるものである。パルス幅変調器（ＰＷＭ）６２は、入力された画像信号のレベルに対応するパルス幅のパルス信号を出力し、そのパルス信号は半導体レーザー（レーザー光源）を駆動するレーザドライバ４１に入力される。
【０１７６】
なお、この画像形成装置にはパターンジェネレーター（不図示）がのせてあり、階調パターンが登録されていて、パルス幅変調器６２に直接信号を渡すことができるようになっている。
【０１７７】
図１３は、露光装置３を示す概略構成図である。露光装置３は、画像読み取りユニット２１から入力される画像信号に基づいて静電荷像担持体１表面をレーザー走査露光Ｌして、静電荷像を形成する。この露光装置３により静電荷像担持体１表面をレーザー走査露光Ｌする場合には、まず画像読み取りユニット２１から入力された画像信号に基づき、発光信号発生器２４により固体レーザー素子２５を所定タイミングで明減（ＯＮ／ＯＦＦ）させる。そして、固体レーザー素子２５から放射された光信号であるレーザー光を、コリメーターレンズ系２６によりほぼ平行な光束に変換し、さらに、矢印ｃ方向に高速回転する回転多面鏡２２により、静電荷像担持体１を矢印ｄ方向（長手方向）に走査することによって、ｆθレンズ群２３、反射ミラー（図１０参照）により静電荷像担持体１表面にレーザスポットが結像される。このようなレーザー走査により、静電荷像担持体１表面には走査分の露光分布が形成され、さらに、各走査毎に静電荷像担持体１表面に対して垂直に所定量だけスクロールさせれば、静電荷像担持体１表面に画像信号に応じた露光分布が得られる。
【０１７８】
即ち、静電荷像担持体１の一様帯電面（例えば−７００Ｖに帯電）に、画像信号に対応してＯＮ／ＯＦＦ発光される固体レーザー素子２５の光を、高速で回転する回転多面鏡２２によって走査することにより、静電荷像担持体１表面には、走査露光パターンに対応した各色の静電荷像が順次形成されていく。
【０１７９】
現像装置４は、図１４に示すように、現像器４１１ａ、４１１ｂ、４１２、４１３、４１４、４１５を有する。これらの現像器には、それぞれ淡色シアントナーを有する現像剤、濃色シアントナーを有する現像剤、淡色マゼンタトナーを有する現像剤、濃色マゼンタトナーを有する現像剤、イエロートナーを有する現像剤、及びブラックトナーを有する現像剤が導入されている。導入されている各現像剤は、磁気ブラシ現像方式によって、静電荷像担持体１に形成された静電荷像を現像し、各色トナー像が静電荷像担持体１に形成される。本発明においては、濃色・淡色シアントナーと濃色・淡色マゼンタトナーとを併用しても良く、またマゼンタトナーを１色のみとしても良く、或いは、シアントナーを１色のみとしても良い。５種の現像剤を用いる場合には、上述の現像器６種から選ばれるいずれの現像器に導入されてもよい。また、残る一つの現像器には他の色味を有する淡色トナー、緑色やオレンジ色、白色といった特色トナー、着色剤を含有しない無色トナー等を有する現像剤を導入してもよい。また、現像器に導入する色順については問わない。これらの現像器として、図１１に示すような二成分現像器は好ましい例の一つである。
【０１８０】
図１１において、二成分現像器は、矢印ｅ方向に回転駆動される現像スリーブ３０を備えており、現像スリーブ３０内にはマグネットローラ３１が固定配置されている。現像容器３２には、現像剤Ｔを現像スリーブ３０表面に薄層形成するための規制ブレード３３が設置されている。
【０１８１】
また、現像容器３２の内部は、隔壁３６によって、現像室（第一室）Ｒ１と攪拌室（第二室）Ｒ２とに区画され、攪拌室Ｒ２の上方には、トナーホッパー３４が配置されている。現像室Ｒ１と攪拌室Ｒ２には、それぞれ搬送スクリュー３７、３８が設置されている。なお、トナーホッパー３４には補給口３５が設けられており、トナー補給時、トナーｔが該補給口３５を経て攪拌室Ｒ２内に落下補給される。
【０１８２】
一方、現像室Ｒ１及び攪拌室Ｒ２内には、上記トナー粒子と磁性キャリア粒子が混合された現像剤Ｔが収容されている。
【０１８３】
また、現像室Ｒ１内の現像剤Ｔは、搬送スクリュー３７の回転駆動によって、現像スリーブ３０の長手方向に向けて搬送される。攪拌室Ｒ２内の現像剤Ｔは、搬送スクリュー３８の回転駆動によって現像スリーブ３０の長手方向に向けて搬送される。搬送スクリュー３８による現像剤搬送方向は、搬送スクリュー３７によるそれとは反対方向である。
【０１８４】
隔壁３６には、紙面と垂直方向である手前側と奥側に、開口部（不図示）がそれぞれ設けられており、搬送スクリュー３７で搬送された現像剤Ｔがこの開口部の１つから搬送スクリュー３８に受け渡され、搬送スクリュー３８で搬送された現像剤Ｔが上記開口部の他の１つから搬送スクリュー３７に受け渡される。トナーは、磁性粒子との摩擦で、潜像を現像するための極性に帯電する。
【０１８５】
アルミニウムや非磁性ステンレス銅等の非磁性材からなる現像スリーブ３０は、現像容器３２の静電荷像担持体１に近接する部位に設けた開口部に設けられており、矢印ｅ方向（反時計方向）に回転してトナー及びキャリアの混合された現像剤Ｔを現像部Ｃに担持搬送する。現像スリーブ３０に担持された現像剤Ｔの磁気ブラシは現像部Ｃで矢印ｃ方向（時計方向）に回転する静電荷像担持体１に接触し、静電荷像はこの現像部Ｃで現像される。
【０１８６】
現像スリーブ３０には、電源（不図示）により交流電圧に直流電圧を重畳した振動バイアス電圧が印加される。潜像の暗部電位（非露光部電位）と明部電位（露光部電位）は、上記振動バイアス電位の最大値と最小値の間に位置している。これによって、現像部Ｃに、向きが交互に変化する交番電界が形成される。この交番電界中で、トナーとキャリアは激しく振動し、トナーが現像スリーブ３０及びキャリアへの静電的拘束を振り切って、潜像に対応して静電荷像担持体１表面の明部に付着する。
【０１８７】
前記振動バイアス電圧の最大値と最小値の差（ピーク間電圧）は１〜５ｋＶ（例えば２ｋＶの矩形波）が好ましく、また、周波数は１〜１０ｋＨｚ（例えば２ｋＨｚ）が好ましい。また、振動バイアス電圧の波形には、矩形波に限らず、サイン波、三角波等を使用できる。
【０１８８】
そして、上記直流電圧成分は、静電荷像の暗部電位と明部電位の間の値のものであるが、絶対値で最小の明部電位よりも暗部電位の方により近い値であることが、暗部電位領域へのカブリトナーの付着を防止する上で好ましい。静電荷像の電位及び現像バイアスの具体的な数値としては、例えば暗部電位−７００Ｖ、明部電位−２００Ｖ、現像バイアスの直流成分−５００Ｖが挙げられる。また、現像スリーブ３０と静電荷像担持体１の最小間隙（この最小間隙位置は現像部Ｃ内にある）は０．２〜１ｍｍ（例えば０．５ｍｍ）であることが好ましい。
【０１８９】
また、規制ブレード３３で規制されて現像部Ｃに搬送される現像剤Ｔの量は、マグネットローラ３１の現像磁極Ｓ１による現像部Ｃでの磁界により形成される現像剤Ｔの磁気ブラシの現像スリーブ３０表面上での高さが、静電荷像担持体１を取り去った状態で、現像スリーブ３０と静電荷像担持体１間の最小間隙値の１．２〜３倍となるような量（例えば先に例示した最小間隙値であれば７００μｍ）であることが好ましい。
【０１９０】
マグネットローラ３１の現像磁極Ｓ１は、現像部Ｃと対向する位置に配置されており、現像磁極Ｓ１が現像部Ｃに形成する現像磁界により現像剤Ｔの磁気ブラシが形成され、この磁気ブラシが静電荷像担持体１に接触してドット分布静電荷像を現像する。その際、磁性キャリアの穂（ブラシ）に付着しているトナーも、この穂ではなくスリーブ表面に付着しているトナーも、静電荷像の露光部に転移して静電荷像を現像する。
【０１９１】
現像磁極Ｓ１による現像磁界の現像スリーブ３０表面上での強さ（現像スリーブ３０表面に垂直な方向の磁束密度）は、そのピーク値が５×１０^−２（Ｔ）〜２×１０^−１（Ｔ）であることが好適である。また、マグネットローラ３１には、上記現像磁極Ｓ１の他に、Ｎ１、Ｎ２、Ｎ３、Ｓ２極を有している。
【０１９２】
ここで、静電荷像担持体１表面の静電荷像を、現像装置３２を用いて二成分磁気ブラシ法により顕像化する現像工程と現像剤Ｔの循環系について説明する。
【０１９３】
現像スリーブ３０の回転によりＮ２極で汲み上げられた現像剤Ｔは、Ｓ２極からＮ１極と搬送され、その途中で規制ブレード３３によってスリーブ上での現像剤層厚が規制され、現像剤薄層を形成する。そして、現像磁極Ｓ１の磁界中で穂立ちした現像剤Ｔが静電荷像担持体１上の静電荷像を現像する。その後、Ｎ３極、Ｎ２極間の反発磁界により、現像スリーブ３０上の現像剤Ｔは現像室Ｒ１内へ落下する。現像室Ｒ１内に落下した現像剤Ｔは、搬送スクリュー３７により攪拌搬送される。
【０１９４】
次に、図１０を用いて上記した画像形成装置の画像形成動作について説明する。
【０１９５】
静電荷像担持体１は、中心支軸を中心に所定の周速度（プロセススピード）で矢印ａ方向（反時計方向）に回転駆動され、その回転過程において一次帯電器２により、本実施の形態では負極性の一様な帯電処理を受ける。
【０１９６】
そして、画像読み取り部Ｂからプリンター部Ａ側に出力される画像信号に対応して変調されたレーザー光による走査露光Ｌが、静電荷像担持体１の一様帯電面に対して露光装置（レーザー走査装置）３から出力され、静電荷像担持体１上に画像読み取り部Ｂにより光電読み取りされた原稿Ｇの画像情報に対応した各色の静電荷像が順次形成される。静電荷像担持体１上に形成された静電荷像は、現像装置４により、上述した二成分磁気ブラシ法によって可視像化される。まず第一色目のトナーを含有する現像器により反転現像されて第一色目のトナー像として可視像化される。
【０１９７】
一方、静電荷像担持体１上への上記トナー像の形成に同期して、給紙カセット１０内に収納された紙などの転写材Ｐが、給紙ローラ１１又は１２により１枚ずつ給送され、レジストローラ１３により所定のタイミングで転写体５に給紙され、吸着ローラ１４によって転写材Ｐが転写体５上に静電吸着される。転写体５上に静電吸着された転写材Ｐは、転写体５の矢印方向（時計方向）の回転によって静電荷像担持体１と対向した位置に移動し、転写帯電器５ａによって転写材Ｐの裏側に前記トナーと逆極性の電荷が付与されて、表面側に静電荷像担持体１上のトナー像が転写される。
【０１９８】
上記転写体５は、例えばポリエチレンテレフタレート樹脂フィルムからなる転写シート５ｃが表面に張設されており、静電荷像担持体１に対して当接、離間自在に設置されている。転写体５は矢印方向（時計方向）に回転駆動される。転写体５内には、転写帯電器５ａ、分離帯電器５ｂ等が設置されている。
【０１９９】
この転写後、静電荷像担持体１上に残留している転写残トナーは、クリーニング装置６によって除去され、静電荷像担持体１は次のトナー像の形成に用いられる。
【０２００】
以下、同様にして静電荷像担持体１上の静電荷像が現像されて、静電荷像担持体１上に形成された各色トナー像が転写帯電器５ａにより転写体５上の転写材Ｐに重ねて転写され、フルカラー画像が形成される。
【０２０１】
そして、転写材Ｐを分離帯電器５ｂによって転写体５上から分離し、分離された転写材Ｐは搬送ベルト８を通して定着装置９に搬送される。定着装置９に搬送された転写材Ｐは、定着ローラ９ａと加圧ローラ９ｂとの間で加熱、加圧されて表面にフルカラー画像が定着された後、排紙ローラ１５によりトレイ１６上に排紙される。
【０２０２】
また、静電荷像担持体１表面は、クリーニング装置６によって転写残トナーが除去され、さらに静電荷像担持体１表面は、前露光ランプ７で除電され、次の画像形成に用いられる。
【０２０３】
また本発明は、図１６に示されるような、タンデム方式のフルカラーの画像形成装置などにも適用可能である。
【０２０４】
図１６に示すタンデム方式の画像形成装置の構成について簡単に説明する。この画像形成装置は、５つの画像形成ユニットを備えており、各画像形成ユニットには、それぞれ感光ドラム（静電荷像担持体）１ａ、１ｂ、１ｃ、１ｄ、１ｅと、一次帯電器２ａ、２ｂ、２ｃ、２ｄ、２ｅと、現像器４ａ、４ｂ、４ｃ、４ｄ、４ｅ等を備えている。現像器４ａ、４ｂ、４ｃ、４ｄ、４ｅには、マゼンタ、濃シアン、淡シアン、イエロー、ブラックの各トナーがそれぞれ収納されている。図１６には、濃シアントナー及び淡シアントナーを用いた形態を示すが、濃マゼンタトナー及び淡マゼンタトナーを替わりに用いても良く、或いは、さらに現像器を増設して、両者を併用しても良い。
【０２０５】
そして、画像形成時には、まず各感光ドラムが各一次帯電器で帯電され、画像読み取り部Ｂからプリンター部Ａ側に出力される画像信号に対応して変調されたレーザー光が露光装置（レーザー走査装置）３から出力され、このレーザー光によって前記各感光ドラムが走査露光されることで、画像読み取りユニット２１により光電読み取りされた原稿Ｇの画像情報に対応したマゼンタ、濃シアン、淡シアン、イエロー、ブラックの各色に対応した静電荷像が、各感光ドラム上にそれぞれ形成される。
【０２０６】
各感光ドラム上に形成された静電荷像は、各現像器によって、それぞれマゼンタ、濃シアン、淡シアン、イエロー、ブラックの各色のトナーにより現像されてトナー像として可視像化される。
【０２０７】
そして、各感光ドラム上における各色トナー画像の形成に同期して、転写ベルト５上に静電吸着されて搬送される紙などの転写材Ｐに各感光ドラムの各色（マゼンタ、濃シアン、淡シアン、イエロー、ブラック）のトナー像が順次多重転写され、フルカラー画像が形成される。
【０２０８】
フルカラー画像が形成された転写材は、定着装置９で加熱、加圧されて定着された後、外部に排紙される。
【０２０９】
【実施例】
以下、本発明を製造例及び実施例により具体的に説明するが、これらは本発明を何ら限定するものではない。
【０２１０】

上記原料をヘンシェルミキサーにより予備混合し、二軸押し出し式混練機により溶融混練し、冷却し、その後ハンマーミルを用いて１〜２ｍｍ程度に粗粉砕し、次いでエアージェット方式による微粉砕機で微粉砕した。得られた微粉砕物を分級し、重量平均粒子径６．４μｍのシアントナー粒子を得た。
【０２１１】
得られたシアントナー粒子１００質量部に、シリコーンオイルとヘキサメチルジシラザンで処理された一次粒径１２ｎｍの乾式シリカ（ＢＥＴ比表面積１２０ｍ^２／ｇ）２．５質量部を外添して、シアントナー１を得た。シアントナー１の物性を表１及び表２に示す。
【０２１２】
（シアントナーの製造例２〜５）
着色剤、荷電制御剤、及び外添剤の添加量を表１に示す数値とした以外はトナーの製造例１と同様にしてシアントナー２〜５を得た。物性を表１及び表２に示す。
【０２１３】
（シアントナーの製造例６）
高速撹拌装置ＴＫ−ホモミキサーを備えた２リットルの四つ口フラスコ中に、イオン交換水３５０質量部と、０．１モル／リットル−Ｎａ_３ＰＯ_４水溶液２２５質量部を添加して、ホモミキサーの回転数を１２０００ｒｐｍに調整し、６５°Ｃに加温せしめた。ここに１．０モル／リットル−ＣａＣｌ_２水溶液３４質量部を徐々に添加し、微小な難水溶性分散剤Ｃａ_３（ＰＯ_４）_２を含む水系分散媒体を調製した。

アトライターを用い上記材料を３時間分散させて重合性単量体組成物とし、その後、重合開始剤である２，２’−アゾビス（２，４−ジメチルバレロニトリル）４質量部を添加した重合性単量体組成物を前記水系分散媒体中に投入し、回転数１２０００ｒｐｍを維持しつつ１５分間造粒した。その後、高速攪拌装置から通常のプロペラ撹拌装置に変更し、内温を８０°Ｃに昇温し、攪拌装置の回転数を１５０ｒｐｍに維持しつつ１０時間重合を行った。重合終了後、冷却し、水系分散媒体中に希塩酸を添加し、難水溶性分散剤を溶解した。さらに洗浄、乾燥を行って、重量平均粒子径５．５μｍのシアントナー粒子を得た。
【０２１４】
得られたシアントナー粒子１００質量部に、シリコーンオイルとヘキサメチルジシラザンで処理された一次粒径１２ｎｍの乾式シリカ（ＢＥＴ比表面積１２０ｍ^２／ｇ）２．５質量部を外添してシアントナー６を得た。シアントナー１と同様にして求めたシアントナー６の物性を表１及び表２に示す。
【０２１５】
（シアントナーの製造例７〜１０）
着色剤、荷電制御剤、及び外添剤の添加量を表１に示す数値とした以外はシアントナーの製造例６と同様にしてシアントナー７〜１０を得た。シアントナー１と同様にして求めたシアントナー７〜１０の物性を表１及び表２に示す。
【０２１６】
【表１】

【０２１７】
【表２】

【０２１８】
（実施例Ａ−１）
シアントナー１と、シリコーン樹脂で表面コートしたフェライトキャリア（平均粒径４２μｍ）とを、トナー濃度が６質量％になるように混合し、二成分現像剤１（濃色用）を調製した。同様に、シアントナー３と、シリコーン樹脂で表面コートしたフェライトキャリア（平均粒径４２μｍ）とを、トナー濃度が６質量％になるように混合し、二成分現像剤３（淡色用）を調製した。
【０２１９】
二成分現像剤１と二成分現像剤３とを組み合わせて、シアントナーキット１とした。
【０２２０】
市販の普通紙フルカラー複写機（カラーレーザー複写機ＣＬＣ１１５０；キヤノン製）のシアン現像器に二成分現像剤１、マゼンタ現像器に二成分現像剤３をセットした。普通紙（カラーレーザーコピア用紙ＴＫＣＬＡ４；キヤノン製）を用い、プリンターモードで淡色シアントナー１２階調、濃色シアントナー１２階調の画像を９０度交差させて重ねたパッチ画像を形成した。プリンターモードの画像データ及び出力画像の例を図９に示す。
【０２２１】
尚、図７は、二成分現像剤１によって形成された画像を示しており、図８は、二成分現像剤３によって形成された画像を示している。このような図７と図８の画像を１枚の紙上に形成することにより、図９の画像は形成されている。
【０２２２】
ＳｐｅｃｔｒｏＳｃａｎ　Ｔｒａｎｓｍｉｓｓｉｏｎ（ＧｒｅｔａｇＭａｃｂｅｔｈ社製）を用い、各パッチのＬ^＊、ａ^＊、ｂ^＊値を測定し、ａ^＊、ｂ^＊値からｃ^＊を求めた。ｃ^＊値を横軸、Ｌ^＊値を縦軸にとり、各パッチの値をプロットしたｃ^＊−Ｌ^＊図を作成した。Ｌ^＊＝６０の直線と、ｃ^＊＝０の直線と、各測定値とに囲まれた領域の面積を求め、再現できる色空間の大きさを比較した。Ｌ^＊値が６０に達しない場合は、最小のＬ^＊値を示す点を通りｃ^＊軸に平行に引いた直線と、Ｌ^＊＝０の直線と、各測定値とに囲まれた領域の面積を求めた。評価結果を表３に示す。
【０２２３】
また、Ｌ^＊値が８５以上１００未満となる低濃度領域、７０以上８５未満となる中濃度領域のパッチ画像をそれぞれ抽出し、これら画像の粒状性を以下の評価基準により目視で評価した。評価結果を表３に示す。
Ａ：粒状性及びガサつきが非常に良好である。
Ｂ：粒状性及びガサつきが良好である。
Ｃ：通常の粒状性、ガサつきがある。
Ｄ：粒状性又はガサつきが若干目立つものの実用の範囲内。
Ｅ：粒状性及びガサつきが目立つ。
【０２２４】
（実施例Ａ−２〜Ａ−５、比較例Ａ−１〜Ａ−５）
トナーキットの構成を表３に示すとおりにした。それ以外は実施例Ａ−１と同様にして画像を評価した。結果を表３に示す。
【０２２５】
【表３】

【０２２６】
（実施例Ａ−６）
二成分現像剤２と二成分現像剤３とを組み合わせて、シアントナーキットとした。
【０２２７】
市販の普通紙フルカラー複写機（カラーレーザー複写機ＣＬＣ１１５０；キヤノン製）のシアン現像器に二成分現像剤２、マゼンタ現像器に二成分現像剤３をセットした。普通紙（カラーレーザーコピア用紙ＴＫＣＬＡ４；キヤノン製）を用い、図１５に基づいて出力した画像について、実施例Ａ−１と同様にして粒状性、ガサつきを以下の評価基準により目視で評価した。評価結果を表４に示す。
Ａ：粒状性及びガサつきが非常に良好である。
Ｂ：粒状性及びガサつきが良好である。
Ｃ：通常の粒状性、ガサつきがある。
Ｄ：粒状性又はガサつきが若干目立つものの実用の範囲内。
Ｅ：粒状性及びガサつきが目立つ。
【０２２８】
また、階調性を以下の評価基準により目視で評価した。評価結果を表４に示す。
Ａ：階調性が非常に良好である。
Ｂ：階調性が良好である。
Ｃ：通常の階調性である。
Ｄ：階調性が不十分である、又は、階調性に違和感がある。
【０２２９】
さらに、実施例Ａ−１と同様にしてｃ^＊−Ｌ^＊図を作成し、Ｌ^＊＝６０の直線と、ｃ^＊＝０の直線と、各測定値とに囲まれた領域の面積を求め、再現できる色空間の大きさを比較した。Ｌ^＊値が６０に達しない場合は、最小のＬ^＊値を示す点を通りｃ^＊軸に平行に引いた直線と、Ｌ^＊＝０の直線と、各測定値とに囲まれた領域の面積を求めた。評価結果を表４に示す。
【０２３０】
（比較例Ａ−６及びＡ−７）
表４に示す二成分現像剤をシアン現像器にセットし、マゼンタ現像器は使用せず、図１７に基づいて出力した以外は実施例Ａ−６と同様にして画像を評価した。結果を表４に示す。
【０２３１】
（実施例Ａ−７及びＡ−８、比較例Ａ−８及びＡ−９）
トナーキットの構成を表４に示すとおりとした。それ以外は実施例Ａ−６と同様にして画像評価を行った結果を表４に示す。
【０２３２】
【表４】

【０２３３】
（ブラックトナー、イエロートナー及びマゼンタトナーの製造例）
シアントナーの製造例１において、着色剤、荷電制御剤、及び外添剤の添加量を表７に示す数値とした以外は同様にしてブラックトナー、イエロートナー及びマゼンタトナーを得た。物性を表５に示す。これらのトナーのそれぞれと、シリコーン樹脂で表面コートしたフェライトキャリア（平均粒径４２μｍ）とを、それぞれトナー濃度が６質量％になるように混合し、ブラック現像剤、イエロー現像剤、及びマゼンタ現像剤を得た。
【０２３４】
【表５】

【０２３５】
（実施例Ａ−９）
トナーキットの構成を以下のとおりにし、図１０に示した電子写真装置を用いて画像形成を行った。それぞれの組み合わせにおける有意差を調べた。
（ａ）：
現像器４１１ａに濃色シアン現像剤（比較例Ａ−６で使用したシアン現像剤１）
現像器４１２に上記マゼンタ現像剤
現像器４１３に上記イエロー現像剤
現像器４１４に上記ブラック現像剤
（ｂ）：
現像器４１１ａに濃色シアン現像剤（実施例Ａ−６で使用したシアン現像剤２）
現像器４１１ｂに淡色シアン現像剤（実施例Ａ−６で使用したシアン現像剤３）
現像器４１２に上記マゼンタ現像剤
現像器４１３に上記イエロー現像剤
現像器４１４に上記ブラック現像剤
（ｃ）：
現像器４１１ｂに淡色シアン現像剤（比較例Ａ−７で使用したシアン現像剤３）
現像器４１２に上記マゼンタ現像剤
現像器４１３に上記イエロー現像剤
現像器４１４に上記ブラック現像剤
（ｄ）：
現像器４１１ａに濃色シアン現像剤（比較例Ａ−９で使用したシアン現像剤１０）
現像器４１１ｂに淡色シアン現像剤（比較例Ａ−９で使用したシアン現像剤５）
現像器４１２に上記マゼンタ現像剤
現像器４１３に上記イエロー現像剤
現像器４１４に上記ブラック現像剤
その結果、（ａ）と比較して、（ｂ）は緑〜紫の二次色においても低濃度部から高濃度部までの全域に渡り粒状性・ガサツキが抑制され、かつ、色再現範囲が広い良好な画像が得られた。
【０２３６】
一方、（ｃ）は、低濃度部における粒状性の低減がみられるものの、表現し得る色相範囲が縮小した。（ｄ）は、（ａ）と比較して二次色における低濃度部の粒状感に低減が見られるものの、中濃度部の粒状性に関しては劣る画像となった。また、表現可能な色空間は増大せず、（ａ）と比較しても小さいものであった。すなわち（ｂ）のように、本発明で規定する色相範囲を有する濃色シアントナーと、淡色シアントナーとを使用することで、本実施例のようなフルカラー電子写真装置において、本発明の効果が十分発揮された。
【０２３７】
（実施例Ａ−１０）
以下の組み合わせで、トナーキットを構成し、市販のフルカラー一成分画像形成装置（クリエティブプロセッサ６６０；キヤノン製）を用いて、実施例Ａ−６と同様に評価した。
（ａ）：
シアン現像器に濃色シアントナー（シアントナー７を濃色シアン一成分現像剤として使用）
（ｂ）：
シアン現像器に淡色シアントナー（シアントナー８を淡色シアン一成分現像剤として使用）
（ｃ）：
シアン現像器に濃色シアントナー（シアントナー７を濃色シアン一成分現像剤として使用）
マゼンタ現像器に淡色シアントナー（シアントナー８を淡色シアン一成分現像剤として使用）
（ｄ）：
シアン現像器にシアントナー（シアントナー１０を濃色シアン一成分現像剤として使用）
マゼンタ現像器にシアントナー（シアントナー９を淡色シアン一成分現像剤として使用）
その結果、（ｃ）の場合に最も粒状性、ガサつきが抑制され、かつ、色再現範囲が広い良好な画像が得られ、一成分現像装置においても本発明の効果が十分に発揮されることが確認された。
【０２３８】

上記原料をヘンシェルミキサーにより予備混合し、二軸押し出し式混練機により溶融混練し、冷却し、その後ハンマーミルを用いて１〜２ｍｍ程度に粗粉砕し、次いでエアージェット方式による微粉砕機で微粉砕した。得られた微粉砕物を分級し、重量平均粒子径６．１μｍのマゼンタトナー粒子を得た。
【０２３９】
得られたマゼンタトナー粒子１００質量部に、シリコーンオイルとヘキサメチルジシラザンで処理された一次粒径１２ｎｍの乾式シリカ（ＢＥＴ比表面積１２０ｍ^２／ｇ）２．４質量部を外添して、濃色マゼンタトナー１を得た。濃色マゼンタトナー１の物性を表６及び表７に示す。
【０２４０】
（マゼンタトナーの製造例２〜６）
着色剤の種類及び添加量と、荷電制御剤及び外添剤の添加量を、それぞれ表８に示す数値とした以外はトナーの製造例１と同様にして濃色マゼンタトナー２及び淡色マゼンタトナー１〜４を得た。濃色マゼンタトナー２及び淡色マゼンタトナー１〜４の物性を表６及び表７に示す。
【０２４１】
（マゼンタトナーの製造例７）
高速撹拌装置ＴＫ−ホモミキサーを備えた２リットルの四つ口フラスコ中に、イオン交換水３５０質量部と、０．１モル／リットル−Ｎａ_３ＰＯ_４水溶液２２５質量部を添加して、ホモミキサーの回転数を１２０００ｒｐｍに調整し、６５°Ｃに加温せしめた。ここに１．０モル／リットル−ＣａＣｌ_２水溶液３４質量部を徐々に添加し、微小な難水溶性分散剤Ｃａ_３（ＰＯ_４）_２を含む水系分散媒体を調製した。

アトライターを用い上記材料を３時間分散させて重合性単量体組成物とし、その後、重合開始剤である２，２’−アゾビス（２，４−ジメチルバレロニトリル）４質量部を添加した重合性単量体組成物を前記水系分散媒体中に投入し、回転数１２０００ｒｐｍを維持しつつ１５分間造粒した。その後、高速攪拌装置から通常のプロペラ撹拌装置に変更し、内温を８０°Ｃに昇温し、攪拌装置の回転数を１５０ｒｐｍに維持しつつ１０時間重合を行った。重合終了後、冷却し、水系分散媒体中に希塩酸を添加し、難水溶性分散剤を溶解した。さらに洗浄、乾燥を行って、重量平均粒子径５．３μｍのマゼンタトナー粒子を得た。
【０２４２】
得られたマゼンタトナー粒子１００質量部に、シリコーンオイルとヘキサメチルジシラザンで処理された一次粒径１２ｎｍの乾式シリカ（ＢＥＴ比表面積１２０ｍ^２／ｇ）２．２質量部を外添して濃色マゼンタトナー３を得た。濃色マゼンタトナー１と同様にして求めた濃色マゼンタトナー３の物性を表６及び表７に示す。
【０２４３】
（マゼンタトナーの製造例８〜１１）
着色剤、荷電制御剤、及び外添剤の添加量を表６に示す数値とした以外はマゼンタトナーの製造例７と同様にして濃色マゼンタトナー４及び淡色マゼンタトナー５〜７を得た。濃色マゼンタトナー１と同様にして求めた濃色マゼンタトナー４及び淡色マゼンタトナー５〜７の物性を表６及び表７に示す。
【０２４４】
【表６】

【０２４５】
【表７】

【０２４６】
（実施例Ｂ−１）
淡色マゼンタトナー１とシリコーン樹脂で表面コートしたフェライトキャリア（平均粒径４２μｍ）とを、トナー濃度が６質量％になるようにそれぞれ混合し、淡色マゼンタ二成分現像剤を調製した。濃色マゼンタトナー１とシリコーン樹脂で表面コートしたフェライトキャリア（平均粒径４２μｍ）とを、トナー濃度が６質量％になるようにそれぞれ混合し、濃色マゼンタ二成分現像剤を調製した。
【０２４７】
淡色マゼンタ二成分現像剤と濃色マゼンタ二成分現像剤とを組み合わせて、マゼンタトナーキット１とした。
【０２４８】
市販の普通紙フルカラー複写機（カラーレーザー複写機ＣＬＣ１１５０；キヤノン製）のシアン現像器に濃色マゼンタトナー１を有する二成分現像剤、マゼンタ現像器に淡色マゼンタトナー１を有する二成分現像剤をセットし、シアン用トナーホッパーには上記濃色マゼンタトナー１、マゼンタ用トナーホッパーに上記淡色マゼンタトナー１をそれぞれ導入した。普通紙（カラーレーザーコピア用紙ＴＫＣＬＡ４；キヤノン製）を用い、プリンターモードで淡色マゼンタトナー１２階調、濃色マゼンタトナー１２階調の画像を９０度交差させて重ねたパッチ画像を形成した。プリンターモードの画像データ及び出力画像の例を図９に示す。
【０２４９】
ＳｐｅｃｔｒｏＳｃａｎ　Ｔｒａｎｓｍｉｓｓｉｏｎ（ＧｒｅｔａｇＭａｃｂｅｔｈ社製）を用い、各パッチのＬ^＊、ａ^＊、ｂ^＊値を測定し、ａ^＊、ｂ^＊値からｃ^＊を求めた。ｃ^＊値を横軸、Ｌ^＊値を縦軸にとり、各パッチの値をプロットしたｃ^＊−Ｌ^＊図を作成した。Ｌ^＊＝６０の直線と、ｃ^＊＝０の直線と、各測定値とに囲まれた領域の面積を求め、再現できる色空間の大きさを比較した。Ｌ^＊値が６０に達しない場合は、最小のＬ^＊値を示す点を通りｃ^＊軸に平行に引いた直線と、Ｌ^＊＝０の直線と、各測定値とに囲まれた領域の面積を求めた。評価結果を表８に示す。
【０２５０】
また、Ｌ^＊値が８５以上１００未満となる低濃度領域、７０以上８５未満となる中濃度領域のパッチ画像をそれぞれ抽出し、これら画像の粒状性を以下の評価基準により目視で評価した。評価結果を表８に示す。
Ａ：粒状性及びガサつきが非常に良好である。
Ｂ：粒状性及びガサつきが良好である。
Ｃ：通常の粒状性、ガサつきがある。
Ｄ：粒状性又はガサつきが若干目立つものの実用の範囲内。
Ｅ：粒状性又はガサつきが目立つ。
【０２５１】
（実施例Ｂ−２〜Ｂ−７、比較例Ｂ−１〜Ｂ−５）
トナーキットの構成を表８に示すとおりにした。それ以外は実施例Ｂ−１と同様にして画像を評価した。結果を表８に示す。
【０２５２】
また、実施例Ｂ−４では、上記評価において良好な結果が得られたマゼンタトナーキット４について、実施例Ｂ−１と同様のパッチ画像を６０００枚連続して画像を出力した後、マゼンタトナーキット４より各トナーをそれぞれのホッパーに補給して、同様にして６０００枚の連続した画像出力を５回繰り返した。連続出力によっても粒状感低減の効果と色再現範囲を拡張する効果が保持され、良好な画像が得られることが確認された。
【０２５３】
【表８】

【０２５４】
（実施例Ｂ−８）
淡色マゼンタトナー２とシリコーン樹脂で表面コートしたフェライトキャリア（平均粒径４２μｍ）とを、トナー濃度が６質量％になるように混合し、淡色マゼンタ二成分現像剤を調製した。さらに濃色マゼンタトナー２を用いる以外は同様にして、濃色マゼンタ二成分現像剤を調製した。
【０２５５】
淡色マゼンタ二成分現像剤と濃色マゼンタ二成分現像剤とを組み合わせて、マゼンタトナーキット１３とした。
【０２５６】
市販の普通紙フルカラー複写機（カラーレーザー複写機ＣＬＣ１１５０；キヤノン製）のシアン現像器に濃色マゼンタ二成分現像剤、マゼンタ現像器に淡色マゼンタ二成分現像剤をセットし、シアン用トナーホッパーには上記濃色マゼンタトナー２、マゼンタ用トナーホッパーに上記淡色マゼンタトナー２をそれぞれ導入した。普通紙（カラーレーザーコピア用紙ＴＫＣＬＡ４；キヤノン製）を用い、図１５に基づいて出力した画像について、実施例Ｂ−１と同様にして粒状性、ガサつきを以下の評価基準により目視で評価した。評価結果を表９に示す。
Ａ：粒状性及びガサつきが非常に良好である。
Ｂ：粒状性及びガサつきが良好である。
Ｃ：通常の粒状性、ガサつきがある。
Ｄ：粒状性又はガサつきが若干目立つものの実用の範囲内。
【０２５７】
Ｅ：粒状性又はガサつきが目立つ。
【０２５８】
また、階調性を以下の評価基準により目視で評価した。評価結果を表９に示す。
Ａ：階調性が非常に良好である。
Ｂ：階調性が良好である。
Ｃ：通常の階調性である。
Ｄ：階調性が不十分である、又は、階調性に違和感がある。
【０２５９】
さらに、実施例Ｂ−１と同様にしてｃ^＊−Ｌ^＊図を作成し、Ｌ^＊＝６０の直線と、ｃ^＊＝０の直線と、各測定値とに囲まれた領域の面積を求め、再現できる色空間の大きさを比較した。Ｌ^＊値が６０に達しない場合は、最小のＬ^＊値を示す点を通りｃ^＊軸に平行に引いた直線と、Ｌ^＊＝０の直線と、各測定値とに囲まれた領域の面積を求めた。評価結果を表９に示す。
【０２６０】
（比較例Ｂ−６及びＢ−７）
濃色マゼンタ二成分現像剤或いは淡色マゼンタ二成分現像剤をマゼンタ現像器にセットし、マゼンタ用トナーホッパーにトナーを導入した。本例ではシアン現像器は使用しなかった。図１７に基づいて出力した以外は実施例Ｂ−８と同様にして画像を評価した。結果を表９に示す。
【０２６１】
（実施例Ｂ−９〜Ｂ−１２、比較例Ｂ−８、Ｂ−９）
トナーキットの構成を表９に示すとおりにした。それ以外は実施例Ｂ−８と同様にして画像を評価した。結果を表９に示す。
【０２６２】
【表９】

【０２６３】
（ブラックトナー、イエロートナー、シアントナーの製造例）
マゼンタトナーの製造例７において、着色剤、荷電制御剤、及び外添剤の添加量を表１０に示す数値とした以外は同様にしてブラックトナー、イエロートナー、シアントナーを得た。物性を表１０に示す。
【０２６４】
【表１０】

【０２６５】
（実施例Ｂ−１３）
以下に示したトナーを用い、実施例Ｂ−８と同様にして二成分現像剤を調製した。トナーキットとしては、調製された４種又は５種の二成分現像剤を有する構成とした。図１０に示した電子写真装置を用いて画像形成を行い、有意差を調べた。
（ａ）：
濃色マゼンタトナー１
上記シアントナー
上記イエロートナー
上記ブラックトナー
（ｂ）：
濃色マゼンタトナー３
淡色マゼンタトナー５
上記シアントナー
上記イエロートナー
上記ブラックトナー
（ｃ）：
淡色マゼンタトナー３
上記シアントナー
上記イエロートナー
上記ブラックトナー
（ｄ）：
濃色マゼンタトナー１
淡色マゼンタトナー３
上記シアントナー
上記イエロートナー
上記ブラックトナー
その結果、（ａ）と比較して、（ｂ）は橙〜紫の二次色においても低濃度部から高濃度部までの全域にわたり粒状性・ガサツキが抑制され、かつ、色再現範囲が広い良好な画像が得られた。
【０２６６】
一方、（ｃ）は、低濃度部における粒状性の低減がみられるものの、表現し得る色相範囲が縮小した。（ｄ）は、（ａ）と比較して２次色における低濃度の粒状性に低減が見られるものの、中濃度部の粒状性が増大した画像となった。また、表現可能な色空間は増大せず、（ａ）と比較しても小さいものであった。すなわち（ｂ）のように、本発明で規定する色相範囲を有する濃色マゼンタトナーと、淡色マゼンタトナーとを使用することで、本実施例のようなフルカラー電子写真装置においても、本発明の効果が十分発揮された。
【０２６７】
（実施例Ｂ−１４）
以下の組み合わせでトナーキットを構成し、市販のフルカラー一成分画像形成装置（クリエティブプロセッサ６６０；キヤノン製）を用いて、実施例Ｂ−８と同様に評価した。
（ａ）：
シアン現像器に濃色マゼンタトナー（濃色マゼンタトナー３を一成分現像剤として使用）
（ｂ）：
シアン現像器に淡色マゼンタトナー（淡色マゼンタトナー５を一成分現像剤として使用）
（ｃ）：
シアン現像器に濃色マゼンタトナー（濃色マゼンタトナー３を一成分現像剤として使用）
マゼンタ現像器に淡色マゼンタトナー（淡色マゼンタトナー５を一成分現像剤として使用）
（ｄ）：
シアン現像器に濃色マゼンタトナー（濃色マゼンタトナー３を一成分現像剤として使用）
マゼンタ現像器に淡色マゼンタトナー（淡色マゼンタトナー７を一成分現像剤として使用）
この結果、（ｃ）の場合に最も粒状性・ガサつきが抑制され、かつ、色再現範囲が広い良好な画像が得られ、一成分現像装置においても本発明の効果が十分に発揮されることが確認された。
【０２６８】
（実施例Ｃ−１）
高速撹拌装置ＴＫ−ホモミキサーを備えた２リットルの四つ口フラスコ中に、イオン交換水３５０質量部と、０．１モル／リットル−Ｎａ_３ＰＯ_４水溶液２２５質量部を添加して、ホモミキサーの回転数を１２０００ｒｐｍに調整し、６５°Ｃに加温せしめた。ここに１．０モル／リットル−ＣａＣｌ_２水溶液３４質量部を徐々に添加し、微小な難水溶性分散剤Ｃａ_３（ＰＯ_４）_２を含む水系分散媒体を調製した。

アトライターを用い上記材料を３時間分散させて重合性単量体組成物とし、その後、重合開始剤である２，２’−アゾビス（２，４−ジメチルバレロニトリル）４質量部を添加した重合性単量体組成物を前記水系分散媒体中に投入し、回転数１２０００ｒｐｍを維持しつつ１５分間造粒した。その後、高速攪拌装置から通常のプロペラ撹拌装置に変更し、内温を８０℃に昇温し、攪拌装置の回転数を１５０ｒｐｍに維持しつつ１０時間重合を行った。重合終了後、冷却し、水系分散媒体中に希塩酸を添加し、難水溶性分散剤を溶解した。さらに洗浄、乾燥を行って、重量平均粒径６．３μｍの淡色シアントナー粒子を得た。
【０２６９】
得られた淡色シアントナー粒子１００質量部に、シリコーンオイルとヘキメチルジシラザンで処理された一次粒径１２ｎｍの乾式シリカ（ＢＥＴ比表面積１２０ｍ^２／ｇ）１．４質量部を外添して、淡色シアントナー１を得た。
【０２７０】
着色剤の種類及び添加量と、荷電制御剤及び外添剤の添加量を表１１に示すように変えた以外は、上記淡色シアントナー１の製造方法と同様にして、淡色マゼンタトナー１を得た。
【０２７１】
高速撹拌装置ＴＫ−ホモミキサーを備えた２リットルの四つ口フラスコ中に、イオン交換水３５０質量部と、０．１モル／リットル−Ｎａ_３ＰＯ_４水溶液２２５質量部を添加して、ホモミキサーの回転数を１２０００ｒｐｍに調整し、６５℃に加温せしめた。ここに１．０モル／リットル−ＣａＣｌ_２水溶液３４質量部を徐々に添加し、微小な難水溶性分散剤Ｃａ_３（ＰＯ_４）_２を含む水系分散媒体を調製した。

アトライターを用い上記材料を３時間分散させて重合性単量体組成物とし、その後、重合開始剤である２，２’−アゾビス（２，４−ジメチルバレロニトリル）４質量部を添加した重合性単量体組成物を前記水系分散媒体中に投入し、回転数１２０００ｒｐｍを維持しつつ１５分間造粒した。その後、高速攪拌装置から通常のプロペラ撹拌装置に変更し、内温を８０°Ｃに昇温し、攪拌装置の回転数を１５０ｒｐｍに維持しつつ１０時間重合を行った。重合終了後、冷却し、水系分散媒体中に希塩酸を添加し、難水溶性分散剤を溶解した。さらに洗浄、乾燥を行って、重量平均粒径５．４μｍの濃色シアントナー粒子を得た。
【０２７２】
得られた濃色シアントナー粒子１００質量部に、シリコーンオイルとヘキサメチルジシラザンで処理された一次粒径１２ｎｍの乾式シリカ（ＢＥＴ比表面積１２０ｍ^２／ｇ）２．５質量部を外添して、濃色シアントナー１を得た。
【０２７３】
着色剤の種類及び添加量と、荷電制御剤及び外添剤の添加量を表１１に示すように変えた以外は、上記濃色シアントナー１の製造方法と同様にして、濃色マゼンタトナー１、イエロートナー１、及びブラックトナー１を得た。各トナーの物性を表１１及び表１３に示す。そして各トナーと、シリコーン樹脂で表面コートしたフェライトキャリア（平均粒径４２μｍ）とをトナー濃度が６質量％になるようにそれぞれ混合し、二成分現像剤を調製した。
【０２７４】
こうして得られた淡色シアントナー１を含有する淡色シアン二成分現像剤、淡色マゼンタトナー１を含有する淡色マゼンタ二成分現像剤、濃色シアントナー１を含有する濃色シアン二成分現像剤、濃色マゼンタトナー１を含有する濃色マゼンタ二成分現像剤、イエロートナー１を含有するイエロー二成分現像剤およびブラックトナー１を含有するブラック二成分現像剤を組み合わせてトナーキット１とした。
【０２７５】
図１０に示す電子写真装置を用いて、上記トナーキット１のトナー構成で画出し評価を行った。この電子写真装置の説明は前述の通りである。本実施例では、現像器４１１ａに淡色シアン二成分現像剤、現像器４１１ｂに淡色マゼンタ二成分現像剤、現像器４１２にイエロー二成分現像剤、現像器４１３に濃色シアン二成分現像剤、現像器４１４に濃色マゼンタ二成分現像剤、現像器４１５にブラック二成分現像剤をそれぞれセットした。二成分現像剤を各現像器にセットするに際し、現像器４１１ａのトナーホッパーには淡色シアントナー１、現像器４１１ｂのトナーホッパーには淡色マゼンタトナー１、現像器４１２のトナーホッパーにはイエロートナー１、現像器４１３のトナーホッパーには濃色シアントナー１、現像器４１４のトナーホッパーには濃色マゼンタトナー１、そして現像器４１５のトナーホッパーにはブラックトナー１を、それぞれ導入した。
【０２７６】
淡色シアントナーと濃色シアントナーを用いて、図１５に基づいて１２階調のシアン画像を形成し、淡色マゼンタトナーと濃色マゼンタトナーを用いて、図１５に基づいて１２階調のマゼンタ画像を形成した。また、イエロートナーおよびブラックトナーを用い、図１７に基づいて１２階調のイエロー画像及びブラック画像をそれぞれ形成した。普通紙（カラーレーザーコピア用紙ＴＫＣＬＡ４；キヤノン製）を用い、プリンターモードでシアン画像とマゼンタ画像、シアン画像とイエロー画像、マゼンタ画像とイエロー画像をそれぞれ９０度交差させて重ねたパッチ画像を形成した。出力画像の例を図９に示す。
【０２７７】
ＳｐｅｃｔｒｏＳｃａｎ　Ｔｒａｎｓｍｉｓｓｉｏｎ（ＧｒｅｔａｇＭａｃｂｅｔｈ社製）を用いて、出力画像のＬ^＊、ａ^＊、ｂ^＊値を測定した。ａ^＊、ｂ^＊値からｃ^＊を求め、ｃ^＊値を横軸、Ｌ^＊値を縦軸にとり、各色についてプロットしたｃ^＊−Ｌ^＊図を作成した。ｃ^＊の値が１以上２０未満となる低濃度域、２０以上４０未満となる中濃度域のパッチ画像をそれぞれ抽出し、これら画像の粒状性を以下の評価基準により目視で評価した。
Ａ：粒状性及びガサつきが非常に良好である。
Ｂ：粒状性及びガサつきが良好である。
Ｃ：通常の粒状性、ガサつきがある。
Ｄ：粒状性又はガサつきが若干目立つものの実用の範囲内。
Ｅ：粒状性又はガサつきが目立つ。
【０２７８】
評価結果を表１４に示す。本実施例によれば、全色域において低濃度部から高濃度部までの全域に渡り粒状性・ガサツキが抑制され、かつ、色再現範囲が広い良好な画像が得られた。
【０２７９】
また、シアン、マゼンタ、レッド、グリーン、ブルーの１２階調パッチ画像を出力し、上記と同様にしてｃ^＊−Ｌ^＊図を作成した。Ｌ^＊＝６０の直線と、ｃ^＊＝０の直線と、各測定値とに囲まれた領域の面積を求め、再現できる色空間の大きさを比較した。Ｌ^＊値が６０に達しない場合は、最小のＬ^＊値を示す点を通りｃ^＊軸に平行に引いた直線と、Ｌ^＊＝０の直線と、各測定値とに囲まれた領域の面積を求めた。評価結果を表１４に示す。
【０２８０】
更に、各トナーの印字率がそれぞれ１０％となる画像を６０００枚連続して出力した。更に各トナーを補給しながら、同様にして６０００枚の連続した画像出力を５回繰り返した。連続出力によっても粒状感低減の効果と色再現範囲を拡張する効果が保持され、良好な画像が得られることが確認された。
【０２８１】
（実施例Ｃ−２）
着色剤の種類及び添加量と、荷電制御剤及び外添剤の添加量を表１１に示すように変えた以外は、上記濃色シアントナー１の製造方法と同様にして、淡色シアントナー２及び濃色マゼンタトナー２を得た。各トナーの物性を表１１及び表１３に示す。
【０２８２】
得られたトナーを用いて、実施例Ｃ−１と同様にして、淡色シアントナー２を含有する淡色シアン二成分現像剤、淡色マゼンタトナー１を含有する淡色マゼンタ二成分現像剤、濃色シアントナー１を含有する濃色シアン二成分現像剤、濃色マゼンタトナー２を含有する濃色マゼンタ二成分現像剤、イエロートナー１を含有するイエロー二成分現像剤およびブラックトナー１を含有するブラック二成分現像剤を調製した。これらの組み合わせをトナーキット２とした。
【０２８３】
上記トナーキット２のトナー構成で画出し評価を行ったところ、実施例Ｃ−１よりは若干色再現範囲が狭いものの、全色域において低濃度部から高濃度部までの全域に渡り粒状性・ガサツキが抑制された良好な画像が得られた。評価結果を表１４に示す。
【０２８４】
（比較例Ｃ−１）
実施例Ｃ−１のトナーキット１において、淡色シアン二成分現像剤と淡色マゼンタ二成分現像剤を除いた４種類の現像剤を有するトナーキット３を形成した。トナーキット３に含まれる各トナーの物性を表１１及び表１３に示す。現像器４１１ａ及び現像器４１１ｂを使用せず、各色のトナーについて図１７に基づいて各色の画像を出力してパッチ画像を得た以外は実施例Ｃ−１と同様にして画像を評価した。その結果、実施例Ｃ−１と比較して色再現範囲が小さく、低濃度部に粒状性・ガサツキが見られた。評価結果を表１４に示す。
【０２８５】
（比較例Ｃ−２）
実施例１のトナーキット１において、濃色シアン二成分現像剤と濃色マゼンタ二成分現像剤を除いた４種類の現像剤を有するトナーキット４を形成した。トナーキット４に含まれる各トナーの物性を表１２及び表１３に示す。現像器４１１ａ及び現像器４１１ｂを使用せず、各色のトナーについて図１７に基づいて各色の画像を出力してパッチ画像を得た以外は実施例Ｃ−１と同様にして画像を評価した。その結果、全色域において低濃度部の粒状性はみられないものの色再現範囲が著しく小さかった。評価結果を表１４に示す。
【０２８６】
（比較例Ｃ−３）
着色剤の種類及び添加量と、荷電制御剤及び外添剤の添加量を表１４に示すように変えた以外は、上記淡色シアントナー１の製造方法と同様にして、淡色シアントナー３、淡色マゼンタトナー２及び濃色シアントナー２を得た。各トナーの物性を表１４及び表１５に示す。
【０２８７】
得られたトナーを用いて、実施例Ｃ−１と同様にして、淡色シアントナー３を含有する淡色シアン二成分現像剤、淡色マゼンタトナー２を含有する淡色マゼンタ二成分現像剤、濃色シアントナー２を含有する濃色シアン二成分現像剤、濃色マゼンタトナー１を含有する濃色マゼンタ二成分現像剤、イエロートナー１を含有するイエロー二成分現像剤およびブラックトナー１を含有するブラック二成分現像剤を調製した。これらの組み合わせをトナーキット５とした。
【０２８８】
上記トナーキット５のトナー構成で、画出し評価を行った。その結果、実施例Ｃ−１と比較して色再現範囲が小さく、また中濃度部の粒状性・ガサツキが目立った。評価結果を表１４に示す。
【０２８９】

上記原料をヘンシェルミキサーにより予備混合し、二軸押し出し式混練機により溶融混練し、冷却し、その後ハンマーミルを用いて１〜２ｍｍ程度に粗粉砕し、次いでエアージェット方式による微粉砕機で微粉砕した。得られた微粉砕物を分級し、重量平均粒径７．３μｍの淡色シアントナー粒子を得た。
【０２９０】
得られた淡色シアントナー粒子１００質量部に、シリコーンオイルとヘキサメチルジシラザンで処理された一次粒径１２ｎｍの乾式シリカ（ＢＥＴ比表面積１２０ｍ^２／ｇ）２．２質量部を外添して、淡色シアントナー４を得た。着色剤の種類及び添加量と、荷電制御剤及び外添剤の添加量を表１２に示すように変えた以外は、上記淡色シアントナー４の製造方法と同様にして、淡色マゼンタトナー３、濃色シアントナー３、濃色マゼンタトナー３、イエロートナー２、及びブラックトナー２を得た。各トナーの物性を表１２及び表１３に示す。
【０２９１】
得られたトナーを用いて、実施例Ｃ−１と同様にして、淡色シアントナー４を含有する淡色シアン二成分現像剤、淡色マゼンタトナー３を含有する淡色マゼンタ二成分現像剤、濃色シアントナー３を含有する濃色シアン二成分現像剤、濃色マゼンタトナー３を含有する濃色マゼンタ二成分現像剤、イエロートナー３を含有するイエロー二成分現像剤およびブラックトナー３を含有するブラック二成分現像剤を調製した。これらの組み合わせをトナーキット６とした。
【０２９２】
上記トナーキット６のトナー構成で、画出し評価を行ったところ、実施例Ｃ−１よりは若干色再現範囲が狭いものの、全色域において低濃度部から高濃度部までの全域に渡り粒状性・ガサツキが抑制された良好な画像が得られた。評価結果を表１４に示す。
【０２９３】
【表１１】

【０２９４】
【表１２】

【０２９５】
【表１３】

【０２９６】
【表１４】

【０２９７】
【発明の効果】
所定の色相を有する濃色トナーと淡色トナーとを組み合わせて用い、画像形成を行うことにより、低濃度領域から高濃度領域まで、粒状感、ガサつきを低減することができ、より高品質な画像を形成することができる。
【図面の簡単な説明】
【図１】本発明で用いられるＬ^＊ａ^＊ｂ^＊表色系の概念を立体的に示す図である。
【図２】本発明で用いられる色相と彩度、色相角度の概念を平面的に示す図である。
【図３】本発明で用いられるシアントナーの色相曲線の一例を示す図である。
【図４】本発明で用いられるシアントナーの彩度、明度曲線の一例を示す図である。
【図５】本発明で用いられるマゼンタトナーの色相曲線の一例を示す図である。
【図６】本発明で用いられるマゼンタトナーの彩度、明度曲線の一例を示す図である。
【図７】本発明の実施例において、二成分現像剤１で形成される１２階調の出力画像を示す図である。
【図８】本発明の実施例において、二成分現像剤３で形成される１２階調の出力画像を示す図である。
【図９】図７及び図８に示す出力画像によって形成されるパッチ画像を示す図である。
【図１０】本発明に用いられるフルカラー画像形成装置の一例を示す縦断面図である。
【図１１】二成分現像器の構成の一例を示す縦断面図である。
【図１２】画像処理の一例を示すブロック図である。
【図１３】本発明に用いられるレーザー露光光学系の一例を示す図である。
【図１４】図１０に示すフルカラー画像形成装置における現像装置を示す図である。
【図１５】本発明に用いられる淡色シアントナーと濃色シアントナーの記録率と階調データとの関係を示すグラフである。
【図１６】本発明に用いられるタンデム方式の画像形成装置の一例を示す縦断面図である。
【図１７】比較例での画像形成における淡色シアントナーと濃色シアントナーの記録率と階調データとの関係を示すグラフである。
【図１８】摩擦帯電量を測定する装置の概略図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a toner kit for developing an electrostatic image in an image forming method such as electrophotography and electrostatic printing, or a toner kit for forming a toner image in a toner jet image forming method. In particular, the present invention relates to a toner kit containing a toner used for a fixing method for fixing a toner image to a transfer material such as a print sheet by heating and pressing. The present invention also relates to an electrophotographic image forming method and an image forming apparatus used for a copying machine, a printer, a facsimile, a digital proof, and the like.
[0002]
[Prior art]
Conventionally, many methods have been known as electrophotography, but in general, the surface of a latent image carrier made of a photoconductive substance is uniformly charged by corona charging or direct charging by a charging roller or the like. After that, an electric latent image is formed on the latent image carrier by irradiating light energy or the like, and then the electric latent image is developed with a positively or negatively charged toner to form a toner image. After transferring the toner image to a transfer material such as paper according to the above, the toner image is fixed on the transfer material by heat, pressure or the like to obtain a copy. Then, at the time of transfer, the remaining toner that has not been transferred to the transfer material is cleaned by various methods, and the above steps are repeated.
[0003]
2. Description of the Related Art In recent years, an image forming apparatus based on an electrophotographic method, such as a printer or a copying machine, has been required to form an image with higher resolution. In particular, with the widespread use of electrophotographic color image forming apparatuses, the applications thereof have been diversified and the demands on the image quality have become strict. That is, in the color image forming apparatus, when copying an image such as a general photograph, catalog, or map, it is required to reproduce extremely finely and faithfully down to a minute portion, and accordingly, the color of the image is It is required to further enhance the vividness of images and to extend the color reproduction range of images.
[0004]
As a method for responding to the above-mentioned requirement, for example, in an electrophotographic image forming apparatus using a digital image signal, when forming the electric latent image, the dot density of dots of a constant potential is adjusted to adjust the electric latent image. Are known. However, according to this method, the toner particles hardly adhere to the dots, the toner particles protrude from the dots, and the gradation of the toner image corresponding to the ratio of the dot density of the black portion to the white portion of the digital latent image. Is likely to be obtained.
[0005]
As a method for responding to the above-mentioned demand, for example, a method of improving the resolution by reducing the size of dots forming the electric latent image is known. However, in this method, the reproducibility of an electric latent image formed from minute dots becomes more difficult, and the resolution tends to be poor. In particular, the gradation tends to be poor in the highlight portion, and the image lacks sharpness. is there. In addition, irregular dot disturbance is perceived as a grainy feeling, which is a factor of deteriorating the image quality of the highlighted portion.
[0006]
In order to solve such a problem, as a method for the above-mentioned request, an image is formed by using a light color toner (light color toner) in the highlight portion and a dark color toner (dark toner) in the solid portion. Methods of forming have been proposed.
[0007]
As such an image forming method, an image forming method of forming an image by combining a plurality of toners having different densities has been proposed. For example, an image forming apparatus in which a light color toner having a maximum reflection density of half or less of the maximum reflection density of a dark color toner is combined, and the toner amount on a transfer material is 0.5 mg / cm.²The image forming apparatus in which the dark toner having the image density of 1.0 or more and the light toner having the image density of less than 1.0 are combined, and the inclination ratio of the recording density between the dark toner and the light toner is 0.2 There has been proposed an image forming apparatus or the like that combines toners between 0.5 and 0.5. However, no consideration has been given to the amount and concentration of the colorant contained in the toner, and a desirable toner configuration has not been sufficiently studied (for example, see Patent Documents 1 to 7).
[0008]
According to the study of the present inventors, in these image forming apparatuses, although the gradation and the granularity in the low density region composed of only the light-colored toner are improved, it is difficult to mix the dark-colored toner and the light-colored toner. It has been clarified that the granularity in the density region has a problem that is rather conspicuous. According to the study by the present inventors, it has been clarified that the above-described image forming apparatus is not sufficiently contrived to extend the color reproduction range.
[0009]
[Patent Document 1]
JP-A-5-25038
[Patent Document 2]
JP-A-8-171252
[Patent Document 3]
JP-A-11-84764
[Patent Document 4]
JP-A-2000-231279
[Patent Document 5]
JP 2000-305339 A
[Patent Document 6]
JP 2000-347476 A
[Patent Document 7]
JP 2001-290319 A
[0010]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problems of the conventional technology. That is, the present invention reduces the graininess and roughness from a low-density region to a high-density region, forms at least a higher-quality image, and provides a dark and light-colored toner capable of forming this image. It is to provide a toner kit having: Another object of the present invention is to provide an image forming method using the dark color toner and the light color toner.
[0011]
Another object of the present invention is to provide at least a vivid cyan image or a magenta image having a wider color reproduction range than before, and to provide a toner kit having a cyan toner or a magenta toner capable of forming this image. It is in. Another object of the present invention is to provide an image forming method using the dark color toner and the light color toner.
[0012]
[Means for Solving the Problems]
The present invention provides a toner kit having a light-colored cyan toner containing at least a binder resin and a colorant and a dark-colored cyan toner containing at least a binder resin and a colorant in a separated state. A^*And the hue in the yellow-blue direction is b^*And the lightness is L^*L^*a^*b^*When a toner-fixed image on plain paper is represented by a system color system, the light-colored cyan toner is represented by b in the fixed image of the light-colored cyan toner.^*A when -20^*Value of (a^* _C1) Is from -19 to -30, and b^*A when -30^*Value (a^* _C2) Is -29 to -45, and the dark cyan toner is b in the fixed image of the dark cyan toner.^*A when -20^*Value of (a^* _C3) Is -7 to -18, and b^*A when -30^*Value (a^* _C4) Is -10 to -28.
[0013]
Further, the present invention contains at least a binder resin and a colorant, and adjusts the hue in the red-green direction to a^*And the hue in the yellow-blue direction is b^*And the lightness is L^*L^*a^*b^*When a toner-fixed image on plain paper is represented by a system color system, b^*A when -20^*Value (a^* _C1) Is from -19 to -30, and b^*A when -30^*Value of (a^* _C2) Is a dark cyan toner used in combination with a light cyan toner of −29 to −45, wherein the dark cyan toner contains at least a binder resin and a colorant;^*a^*b^*When a toner-fixed image on plain paper is represented by a system color system, b^*A when -20^*Value (a^* _C3) Is -7 to -18, and b^*A when -30^*Value (a^* _C4) Is -10 to -28.
[0014]
Further, the present invention contains at least a binder resin and a colorant, and adjusts the hue in the red-green direction to a^*And the hue in the yellow-blue direction is b^*And the lightness is L^*L^*a^*b^*When a toner-fixed image on plain paper is represented by a system color system, b^*A when -20^*Value (a^* _C3) Is -7 to -18, and b^*A when -30^*Value of (a^* _C4) Is a light cyan toner used in combination with a dark cyan toner in which -10 to -28, wherein the light cyan toner contains at least a binder resin and a colorant;^*a^*b^*When a toner-fixed image on plain paper is represented by a system color system, b^*A when -20^*Value (a^* _C1) Is from -19 to -30, and b^*A when -30^*Value (a^* _C2) Is -29 to -45.
[0015]
Further, the present invention provides a step of forming an electrostatic image on a charged electrostatic image carrier, a step of developing the formed electrostatic image with toner to form a toner image, and a step of forming a toner image. Transferring the toner image onto a transfer material, and fixing the transferred toner image on the transfer material by heat and pressure to form a fixed image, wherein the step of forming the electrostatic charge image comprises: Forming a first electrostatic image developed with a first toner selected from a light cyan toner and a dark cyan toner; and a first electrostatic image formed from the light cyan toner and the dark cyan toner. Forming a second electrostatic image to be developed with a second toner other than the toner, the step of forming the toner image, developing the first electrostatic image with the first toner Forming a first cyan toner image; and Developing the charge image with a second toner to form a second cyan toner image, wherein the transferring includes transferring the first cyan toner image and the second cyan toner image to a transfer material. Forming a cyan toner image in which these toner images are superimposed on a transfer material, wherein the light cyan toner and the dark cyan toner contain at least a binder resin and a coloring agent, and Hue in the direction^*And the hue in the yellow-blue direction is b^*And the lightness is L^*L^*a^*b^*When a toner-fixed image on plain paper is represented by a system color system, the light-colored cyan toner is represented by b in the fixed image of the light-colored cyan toner.^*A when -20^*Value (a^* _C1) Is from -19 to -30, and b^*A when -30^*Value (a^* _C2) Is -29 to -45, and the dark cyan toner is b in the fixed image of the dark cyan toner.^*A when -20^*Value of (a^* _C3) Is -7 to -18, and b^*A when -30^*Value of (a^* _C4) Is -10 to -28.
[0016]
Further, the present invention provides a toner kit comprising a light-colored magenta toner containing at least a binder resin and a colorant, and a dark-colored magenta toner containing at least a binder resin and a colorant, in a separated state. The hue in the green direction is a^*And the hue in the yellow-blue direction is b^*And the lightness is L^*L^*a^*b^*When a toner-fixed image on plain paper is represented by a system color system, the light-colored magenta toner is a^*B when is 20^*Value (b^* _M1) Is -18 to 0, and a^*B when is 30^*Value (b^* _M2) Is -26 to 0, and the dark magenta toner is a^*B when is 20^*Value (b^* _M3) Is from -16 to 2, and a^*B when is 30^*Value (b^* _M4) Is from -24 to 3, and b^* _M1And b^* _M3Difference (b^* _M1-B^* _M3) Is -8 to -1 and b^* _M2And b^* _M4Difference (b^* _M2-B^* _M4) Is -12 to -1.
[0017]
Further, the present invention contains at least a binder resin and a colorant, and adjusts the hue in the red-green direction to a^*And the hue in the yellow-blue direction is b^*And the lightness is L^*L^*a^*b^*When a toner-fixed image on plain paper is represented by a system color system, a^*B when is 20^*Value (b^* _M1) Is -18 to 0, and a^*B when is 30^*Value (b^* _M2) Is a dark magenta toner used in combination with a light magenta toner in which -26 to 0, wherein the dark magenta toner contains at least a binder resin and a colorant;^*a^*b^*When a toner-fixed image on plain paper is represented by a system color system, a^*B when is 20^*Value (b^* _M3) Is from -16 to 2, and a^*B when is 30^*Value (b^* _M4) Is from -24 to 3, and b^* _M1And b^* _M3Difference (b^* _M1-B^* _M3) Is -8 to -1 and b^* _M2And b^* _M4Difference (b^* _M2-B^* _M4) Is -12 to -1.
[0018]
Further, the present invention contains at least a binder resin and a colorant, and adjusts the hue in the red-green direction to a^*And the hue in the yellow-blue direction is b^*And the lightness is L^*L^*a^*b^*When a toner-fixed image on plain paper is represented by a system color system, a^*B when is 20^*Value (b^* _M3) Is from -16 to 2, and a^*B when is 30^*Value (b^* _M4) Is a light-colored magenta toner used in combination with a dark-colored magenta toner having -24 to 3, wherein the light-colored magenta toner contains at least a binder resin and a colorant, and a^*B when is 20^*Value (b^* _M1) Is -18 to 0, and a^*B when is 30^*Value (b^* _M2) Is from -26 to 0, and b^* _M1And b^* _M3Difference (b^* _M1-B^* _M3) Is -8 to -1 and b^* _M2And b^* _M4Difference (b^* _M2-B^* _M4) Is from -12 to -1.
[0019]
Further, the present invention provides a step of forming an electrostatic image on a charged electrostatic image carrier, a step of developing the formed electrostatic image with toner to form a toner image, and a step of forming the formed toner image. Transferring the toner image onto a transfer material, and fixing the transferred toner image on the transfer material by heat and pressure to form a fixed image, wherein the step of forming the electrostatic charge image comprises: Forming a first electrostatic charge image developed with a first toner selected from a light-colored magenta toner and a dark-colored magenta toner; and a first electrostatic charge image selected from a light-colored magenta toner and a dark-colored magenta toner. Forming a second electrostatic image to be developed with a second toner other than the toner, the step of forming the toner image, developing the first electrostatic image with the first toner Forming a first magenta toner image; Developing a second electrostatic image with a second toner to form a second magenta toner image, wherein the transferring step comprises combining the first magenta toner image and the second magenta toner image. Transferring to a transfer material, including the step of forming a magenta toner image on which these toner images are superimposed on the transfer material, the light color magenta toner and the dark color magenta toner contain at least a binder resin and a colorant, Red-green hue is a^*And the hue in the yellow-blue direction is b^*And the lightness is L^*L^*a^*b^*When a toner-fixed image on plain paper is represented by a system color system, the light-colored magenta toner is a^*B when is 20^*Value (b^* _M1) Is -18 to 0, and a^*B when is 30^*Value (b^* _M2) Is -26 to 0, and the dark magenta toner is a^*B when is 20^*Value (b^* _M3) Is from -16 to 2, and a^*B when is 30^*Value (b^* _M4) Is from -24 to 3, and b^* _M1And b^* _M3Difference (b^* _M1-B^* _M3) Is -8 to -1 and b^* _M2And b^* _M4Difference (b^* _M2-B^* _M4) Is from -12 to -1.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
The toner kit of the present invention has the light toner and the dark toner specified in the present invention in a separated state, and the toner kit of the present invention separates the toner other than the cyan toner or the magenta toner containing the dark toner. It may have further in the state. The toner kit of the present invention can be incorporated into a developing device having two or more independent toner containers, an image forming device, a process cartridge, or the like. Further, the toner kit of the present invention is a container for accommodating two or more toners or developers to be introduced into these developing devices and the like in a separated state. Hereinafter, each toner constituting the toner kit will be described.
[0021]
First, the cyan toner will be described.
[0022]
The light-color cyan toner and the dark-color cyan toner used in the present invention contain at least a binder resin and a colorant, and have a hue in the red-green direction of a.^*And the hue in the yellow-blue direction is b^*And the lightness is L^*L^*a^*b^*When a toner-fixed image on plain paper is represented by a system color system, the light cyan toner is b in the fixed image of the light cyan toner.^*A when -20^*Value of (a^* _C1) Is from -19 to -30, and b^*A when -30^*Value of (a^* _C2) Is -29 to -45, and the dark cyan toner is b in the fixed image of the dark cyan toner.^*A when -20^*Value of (a^* _C3) Is -7 to -18, and b^*A when -30^*Value of (a^* _C4) Are -10 to -28.
[0023]
Said L^*a^*b^*The system color system is generally used as a useful means for numerically expressing a color. L^*a^*b^*FIG. 1 shows a three-dimensional conceptual diagram of the system color system. In FIG. 1, a on the horizontal axis^*And b^*Each represents a hue. Hue is a measure of hue, such as red, yellow, green, blue, and purple. In the present invention, the hue in the red-green direction is a^*And the hue in the yellow-blue direction is b^*And L on the vertical axis^*Represents lightness. Lightness can be compared regardless of hue and indicates the degree of color brightness.
[0024]
In the present invention, a^* _C1Is -19 to -30, and a^* _C2Is -29 to -45, and a light cyan toner^* _C3Is -7 to -18, and a^* _C4The above-mentioned problem is solved by using a dark cyan toner having a value of −10 to −28, and there is no graininess, excellent gradation, and a wide color reproduction range from a low density portion to a high density region. A good image can be obtained. In the present invention, the a^* _C1Is -26 to -21, and the a^* _C2Is -37 to -30, and the a^* _C3Is -18 to -11, and a^* _C4Is more preferably from -27 to -20 from the above viewpoint.
[0025]
The image formed by the cyan toner has a color with high sensitivity to humans and a color with relatively low sensitivity. In an image formed as a blue-dark blue color, the gradation property is easily recognized even in a high density portion where the rate of change of the image density is small. Further, in a low-density portion existing in the image as dots or lines, there is a feature that the fluctuation of the dots or lines is easily perceived as a granular feeling. An image formed as a light green to light blue color has a feature that even if dots and lines are disturbed to some extent, it is hard to be perceived as a granular feeling. According to the above-described hue range, the granularity is well suppressed even in the middle density portion where the light cyan toner and the dark cyan toner are mixed.
[0026]
a^* _C1Is greater than -19 (close to positive) or a^* _C2Is larger than -29, the granularity of the low-density portion tends to increase, and a^* _C1Is smaller than -30 (large negative), a^* _C2Is smaller than -45, the granularity of the medium density portion may increase. a^* _C3Is greater than -7 or a^* _C4Is greater than −10, the granularity of the middle density portion tends to increase, and a^* _C3Is smaller than -18 or a^* _C4Is smaller than -28, sufficient gradation may not be obtained in the high density portion. The hue ranges of the light-color cyan toner and the dark-color cyan toner are achieved by controlling the type and content of the colorant, the toner particle size, and the like.
[0027]
In the present invention, the a^* _C1And a^* _C3And the difference (a^* _C1-A^* _C3) Is preferably from -22 to -1, more preferably from -12 to -3, and a^* _C2And a^* _C4And the difference (a^* _C2-A^* _C4) Is preferably from -33 to -1, more preferably from -15 to -3. a^* _C1-A^* _C3Is greater than -1 or a^* _C2-A^* _C4Is larger than -1, the width of the gradation that can be expressed from the low density portion to the high density portion may be small. a^* _C1-A^* _C3Is smaller than −22 or a^* _C2-A^* _C4Is smaller than -33, the effect of continuously reducing the granularity from the low density portion to the high density portion may be reduced.
[0028]
In the present invention, the light-colored cyan toner is c^*L when is 30^*Value (L^* _C1) Is 85 to 90, and the dark cyan toner is c^*L when is 30^*Value (L^* _C2) Is preferably in the range from 74 to 84. Where c^*Is the saturation, which is obtained by the following equation, and indicates the degree of color vividness.
[0029]
(Equation 5)

[0030]
Said L^* _C1And L^* _C2Is within the above range, it is possible to improve the vividness of the image and extend the color reproduction range while maintaining the effect of reducing the graininess. L^* _C1Is less than 85, the effect of reducing the granularity of the low-density portion may be reduced.^* _C1Is in the range of more than 90, the effect of reducing the graininess in the middle density portion may be reduced. L^* _C2Is less than 74, the effect of reducing the feeling of granularity in the middle density portion may be reduced.^* _C2Is more than 84, the gradation of the high density portion may not be sufficiently obtained.
[0031]
In the present invention, the light-color cyan toner has a hue angle (H^* _C1) Is 214 to 226 °, and the dark cyan toner has a hue angle (H^* _C2) Is preferably 228 to 260 °. The hue angle is, as shown in FIG.^*-B^*In coordinates, the amount of toner adhered on paper is 0.5 mg / cm²Hue of the image (a^*, B^*) And the origin, and a positive a^*The angle between the axis and the positive^*In a counterclockwise direction from the axis, the straight line and the positive a^*It is the angle between the axis. A hue angle can easily represent a particular hue regardless of brightness.
[0032]
H^* _C1Exceeds 226 °, the effect of reducing the granularity of the low-density portion may be reduced.^* _C1Is less than 214 °, the effect of reducing the graininess in the middle density portion may be reduced. H^* _C2Exceeds 260 °, the effect of reducing the feeling of granularity in the medium density portion may be reduced.^* _C2Is less than 228 °, the gradation of the high density portion may not be sufficiently obtained.
[0033]
Next, the magenta toner will be described.
[0034]
The light magenta toner and the dark magenta toner used in the present invention are L^*a^*b^*When a toner-fixed image on plain paper is represented by a system color system, light magenta toner is a^*B when is 20^*Value (b^* _M1) Is -18 to 0, and a^*B when is 30^*Value (b^* _M2) Is from −26 to 0, and the dark magenta toner has a value a in the fixed image of the dark magenta toner.^*B when is 20^*Value (b^* _M3) Is from -16 to 2, and a^*B when is 30^*Value (b^* _M4) Is from -24 to +3, and b^* _M1And b^* _M3Difference (b^* _M1-B^* _M3) Is -8 to -1 and b^* _M2And b^* _M4Difference (b^* _M2-B^* _M4) Are -12 to -1.
[0035]
In the present invention, b^* _M1Is -18 to 0, and b^* _M2A light magenta toner having -26 to 0, and b^* _M3Is from -16 to 2, and b^* _M4The above-mentioned problem is solved by using a dark-colored magenta toner having a value of −24 to 3, and there is no graininess, excellent gradation, and a wide color reproduction range from a low density portion to a high density region. Can obtain a perfect image. In the present invention, from the above viewpoint, b^* _M1Is -13 to -4, and b^* _M2A light magenta toner having a value of -15 to -5, and b^* _M3Is -12 to 0 (more preferably, b^* _M3Is -11 to -2), and b^* _M4Is -15 to 0 (more preferably, b^* _M4Is more preferably -14 to -4).
[0036]
An image formed by magenta toner has a color with high sensitivity to humans and a color with relatively low sensitivity. In an image formed as magenta close to red, the gradation is easily recognized even in a high-density portion where the change rate of the image density is small. Further, in a low-density portion existing in the image as dots or lines, there is a feature that the fluctuation of the dots or lines is easily perceived as a granular feeling. On the other hand, an image formed as magenta, which is close to purple, has a feature that even if dots and lines are disturbed to some extent, it is hard to be perceived as a granular feeling. According to the above-described hue range, the granularity is favorably suppressed even in the middle density portion where the light color magenta toner and the dark color magenta toner are mixed.
[0037]
b^* _M1Is greater than 0 (has a positive value), b^* _M2Is larger than 0, the granularity of the low density portion tends to increase, and b^* _M1Is smaller than -18 (large negative), b^* _M2Is smaller than -26, the granularity of the medium density portion may increase. b^* _M3Is greater than 2 or b^* _M4Is greater than 3, the granularity of the middle density portion tends to increase, and b^* _M3Is smaller than -16, or b^* _M4Is smaller than −24, sufficient gradation may not be obtained in the high density portion.
[0038]
In the present invention, the b^* _M1And b^* _M3Difference (b^* _M1-B^* _M3) Is -8 to -1 and b^* _M2And b^* _M4Difference (b^* _M2-B^* _M4) Is from -12 to -1. Also, b^* _M1And b^* _M3Difference (b^* _M1-B^* _M3) Is more preferably from -7 to -1, more preferably from -7 to -2, and b^* _M2And b^* _M4Difference (b^* _M2-B^* _M4) Is more preferably from -11 to -2, and still more preferably from -10 to -2. b^* _M1-B^* _M3Is greater than -1 or b^* _M2-B^* _M4Is larger than -1, the width of the gradation that can be expressed from the low density portion to the high density portion may be small. b^* _M1-B^* _M3Is smaller than -8, or b^* _M2-B^* _M4Is smaller than −12, the effect of continuously reducing the granularity from the low density portion to the high density portion may be reduced. The hue range of the light-color magenta toner and the dark-color magenta toner is achieved by controlling the type and content of the colorant, the toner particle size, and the like.
[0039]
Further, the above effect is particularly remarkable when the light-colored magenta toner and the dark-colored magenta toner have triboelectric charging characteristics of the same polarity, and the difference between the two-component tribo values of the two magenta toners is 5 mC / kg or less in absolute value. From the low-density portion to the high-density region, it is possible to obtain a good image with no graininess and excellent gradation.
[0040]
The two-component tribo value of the toner can be measured by a known method. In the present invention, it is preferable to use a device for measuring the two-component tribo value shown in FIG. First, a mixture of a sample and a carrier whose two-component tribo value is to be measured, that is, in the case of a toner, a mass ratio of the toner to the carrier of 1: in a metal measuring container 92 having a 500-mesh screen 93 at the bottom. In the case of a mixture of No. 19 and an external additive, a mixture of the external additive and the carrier at a mass ratio of 1:99 is placed in a polyethylene bottle of a 50 to 100 ml container and shaken by hand for about 10 to 40 seconds. Then, about 0.5 to 1.5 g of the mixture (developer) is charged, and a metal lid 94 is closed. The mass of the entire measurement container 92 at this time is defined as W1 (g). Next, in the suction device 91 (at least a portion in contact with the measurement container 92 is an insulator), the pressure is suctioned from the suction port 97 and the air volume control valve 96 is adjusted to adjust the pressure of the vacuum gauge 95 to 250 mmAq. In this state, suction is sufficiently performed, preferably for 2 minutes, to remove the toner by suction. The potential of the electrometer 99 at this time is set to V (volt). Here, 98 is a capacitor whose capacity is C (mF). Further, the mass of the entire measurement container after suction is weighed, and the value at this time is defined as W2 (g). The binary tribo value (mC / kg) of this sample is calculated as in the following equation.
Binary tribo value (mC / kg) of sample = C × V / (W1−W2)
(However, the measurement conditions are 23 ° C. and 60% RH.)
As a carrier used for the measurement, a coated ferrite carrier having carrier particles of 70 to 90% by mass of 250 mesh pass / 350 mesh on was used.
[0041]
Specifically, a carrier manufactured as follows was used.
[0042]
20 parts of toluene, 20 parts of butanol, 20 parts of water and 40 parts of ice are placed in a four-necked flask, and while stirring, CH₃SiCl₃: 2 mol and (CH₃)₂SiCl₂: 40 mol of a mixture with 3 mol was added, and the mixture was further stirred for 30 minutes, and then subjected to a condensation reaction at 60 ° C for 1 hour to obtain a silicone resin.
・ 100 parts of the above silicone resin (organopolysiloxane silicone resin)
・ C₆H₅-NHCH₂CH₂CH₂Si (OCH₃)₃部 2 copies
The mixture of the above-mentioned raw materials was coated on a Cu-Zn-Fe-based ferrite core by 0.5% by mass to produce a carrier. This silicone resin-coated ferrite carrier has an atomic ratio of Si / C = 0.6 on the carrier particle surface by XPS measurement, and the total number of metal atoms Cu, Zn, and Fe is 0.5% by number. Met. The weight average particle size was 42 μm, and in the weight distribution, particles having a particle size of 26 μm to less than 35 μm were 19% by weight, particles having a particle size of 70 μm or more were 0% by weight, and the current value when a voltage of 500 V was applied was 70 μA. Was.
[0043]
In the present invention, the light-colored magenta toner is c.^*L when is 30^*Value (L^* _M1) Is 78 to 90, and the dark magenta toner is c.^*L when is 30^*Value (L^* _M2) Is 74 to 87, and L^* _M1And L^* _M2Difference (L^* _M1-L^* _M2) Is preferably from 0.4 to 12.
[0044]
Said L^* _M1And L^* _M2Is within the above range, it is possible to improve the vividness of the image and extend the color reproduction range while maintaining the effect of reducing the graininess. L^* _M1Is less than 78, the effect of reducing the graininess in the low-density portion may be reduced.^* _M1Is in the range of more than 90, the effect of reducing the graininess in the middle density portion may be reduced. L^* _M2Is less than 74, the effect of reducing the feeling of granularity in the middle density portion may be reduced.^* _M2Is more than 87, the gradation of the high density portion may not be sufficiently obtained. Also, (L^* _M1-L^* _M2) Is less than 0.4, the effect of extending the color gamut may be reduced.^* _M1-L^* _M2) Is more than 12, the effect of reducing the graininess may be reduced.
[0045]
In the present invention, the light color magenta toner has a hue angle (H^* _M1) Is 325 to 350 °, and the dark magenta toner has a hue angle (H^* _M2) Is 340 to 10 ° and H^* _M1And H^* _M2Angle (H^* _M2-H^* _M1) Is preferably 2 to 30 °. The hue angle can be measured in the same manner as in the case of the dark and light cyan toner.
[0046]
H^* _M1Exceeds 350 °, the effect of reducing the graininess in the low-density portion may be reduced.^* _M1Is less than 325 °, the effect of reducing the graininess in the middle density portion may be reduced. H^* _M2Exceeds 10 °, the effect of reducing the feeling of granularity in the middle density portion may be reduced.^* _M2Is less than 340 °, the gradation of the high density portion may not be sufficiently obtained. Also, (H^* _M2-H^* _M1) Is less than 2, the effect of extending the color gamut may be reduced.^* _M2-H^* _M1) Is more than 30, the effect of reducing graininess may be reduced.
[0047]
Next, items common to the cyan toner and the magenta toner will be described.
[0048]
A of the toner used in the present invention^*, B^*, C^*, L^*Is determined by forming an appropriate toner-fixed image on plain paper using each toner and measuring the hue and brightness of this image. As an image forming apparatus for forming a toner-fixed image, a commercially available plain paper full-color copying machine (for example, a color laser copying machine CLC1150; manufactured by Canon Inc.) can be used. As the plain paper, for example, color laser copier paper TKCLA4; manufactured by Canon Inc. can be used. The appropriate toner-fixed image includes an image in which the amount of toner on paper is changed, for example, a 200-line 16-gradation image (using a line image of 200 lines per inch, a 16-gradation image as in FIG. 7). Formed) can be used.
[0049]
That is, in the present invention, when an image is output using a generally used apparatus under conditions capable of forming a good image according to the apparatus used, a^*, B^*, C^*, L^*Are considered to be within the scope of the present invention.
[0050]
The measuring method is as described above in a.^*, B^*, And L^*The method is not particularly limited as long as the method can at least measure SpectroScan, for example, a method of measuring using SpectroScan @ Transmission (manufactured by Gretag Macbeth) as a measuring device. The measurement conditions when this apparatus is used include an observation light source: D50, an observation field of view: 2 °, a density: DIN @ NB, a white standard: Pap, and a filter: none.
[0051]
a^*Is the horizontal axis, b^*Is the vertical axis, and a is obtained by measuring the toner-fixed image.^*Value and b^*Is plotted, and a^*-B^*Create a coordinate map. This a^*-B^*From the coordinate diagram, b^*A when -20 and -30^*Find the value of. Representative measurement results are shown in FIGS.
[0052]
Furthermore, c^*Is the horizontal axis, L^*Is the vertical axis, and the a^*-B^*C obtained from the coordinate diagram and the above equation^*Value and L^*Is plotted, and c^*-L^*Create a coordinate map. This c^*-L^*From the coordinate diagram, c^*L when is 30^*Find the value of. Representative measurement results are shown in FIGS.
[0053]
In the present invention, examples of the colorant that can be used for the light-color cyan toner and the dark-color cyan toner include a copper phthalocyanine compound and its derivative, an anthraquinone compound, and a basic dye lake compound. As the colorant that can be particularly preferably used, specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66. As the colorant that can be used for the light cyan toner and the dark cyan toner, in addition to the cyan colorant described above, for example, another colorant such as a yellow colorant or a magenta colorant described below may be used. By mixing these colorants, a^*, B^*, C^*, L^*Can be adjusted.
[0054]
In the present invention, as a colorant that can be used for the light-color magenta toner and the dark-color magenta toner, a condensed azo compound, a diketopyrrolopyrrole compound, an anthraquinone, a quinacridone compound, a basic dye lake compound, a naphthol compound, a benzimidazolone compound Thioindigo compounds and perylene compounds. Particularly preferred colorants include C.I. I. Pigment Red 31, 48: 1, 48: 2, 48: 3, 48: 4, 57: 1, 88, 95, 144, 146, 150, 177, 202, 214, 220, 221, 254, 264, 269, C. I. Pigment Violet 19. Colorants that can be used for the light-colored magenta toner and the dark-colored magenta toner, in addition to the above-described magenta colorant, for example, other colorants such as a yellow colorant and a cyan colorant described below may be used, By mixing these colorants, a^*, B^*, C^*, L^*Can be adjusted.
[0055]
These colorants can be used alone or in a mixed state, and can also be used in a solid solution state. The colorant is selected from the viewpoints of hue angle, saturation, lightness, weather resistance, OHP transparency, and dispersibility in toner particles. It is preferable to use a pigment as the colorant in the present invention. The preferred amount of the colorant in the present invention varies depending on the type of the colorant to be used and the like. The light cyan toner and the light magenta toner are 0.4 to 1.5% by mass based on the total amount of the toner, The amount of the toner and the dark magenta toner is 2.5 to 8.5% by mass based on the total amount of the toner.
[0056]
In the present invention, the light-colored toner (cyan, magenta) is developed in order to faithfully develop a minute latent image and obtain a good image excellent in gradation from a low-density portion to a high-density region without graininess. And the weight average particle size (Db) of the dark toner (cyan, magenta) are preferably 3 to 9 μm. When Da and Db are in the above ranges, the transfer efficiency is hardly reduced, and non-uniform unevenness of an image due to fog or poor transfer is less likely to occur.
[0057]
In the present invention, the ratio (Da / Db) of the above-mentioned Da and Db is obtained in order to obtain a higher definition image while forming an image having no gradation from a low density portion to a high density region and excellent in gradation. ) Is preferably in the range of 1.0 to 1.5, and more preferably in the range of 1.05 to 1.4. Da and Db can be adjusted by a method for producing a toner such as a polymerization method, and can also be adjusted by classifying the generated toner particles or mixing classified products.
[0058]
The average particle size and the particle size distribution of the toner can be measured by a known method. In the present invention, the measurement is preferably performed using a measuring device such as a Coulter Counter TA-II or a Coulter Multisizer (manufactured by Coulter Inc.).
[0059]
In such a measuring method, a measuring instrument such as a Coulter Counter TA-II or a Coulter Multisizer (manufactured by Coulter), an interface for outputting a number distribution and a volume distribution (manufactured by Nikkaki), and a PC9801 personal computer (manufactured by NEC) And an electrolyte is used. As the electrolytic solution, a 1% NaCl aqueous solution prepared using primary sodium chloride or, for example, ISOTON®R-II (manufactured by Coulter Scientific Japan) can be used.
[0060]
As a specific measurement method, 0.1 to 5 ml of a surfactant (preferably an alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the aqueous electrolytic solution, and 2 to 20 mg of a measurement sample is added. Dispersion treatment is performed for about 1 to 3 minutes with a disperser, and this is measured with the measuring device. For example, the volume distribution and the number distribution are calculated by measuring the volume and the number of toner particles having a size of 2 μm or more by the Coulter Counter TA-II using an aperture of 100 μm as the aperture. Then, the weight average particle diameter (D4) and the number average particle diameter (D1) are determined.
[0061]
The light-colored cyan toner, the dark-colored cyan toner, the light-colored magenta toner, and the dark-colored magenta toner used in the present invention are formed by a known toner material such as a binder resin, a release agent, and a charge control agent, in addition to the colorant. Be composed.
[0062]
In the present invention, the charge control agent is used for suitably adjusting the charging characteristics of both cyan toners. Note that the charging characteristics of the two cyan toners can also be adjusted by controlling the frictional charging of the toner during image formation, or by using other types of toner materials.
[0063]
Known charge control agents can be used as the charge control agent used in the present invention. In particular, a charge control agent that is colorless, has a high toner charging speed, and can stably maintain a constant charge amount is preferable. Further, in the case of producing toner particles by a polymerization method, a charge control agent having no polymerization inhibitory property and having no solubilized substance in an aqueous system is particularly preferable. As the charge control agent, a negative charge control agent or a positive charge control agent is used.
[0064]
Examples of negative charge control agents include salicylic acid metal compounds, naphthoic acid metal compounds, dicarboxylic acid metal compounds, polymer compounds having sulfonic acid or carboxylic acid in the side chain, boron compounds, urea compounds, silicon compounds, and calixarenes. Available. As the positive charge control agent, a quaternary ammonium salt, a polymer compound having the quaternary ammonium salt in a side chain, a guanidine compound, and an imidazole compound can be used. The charge control agent is preferably used in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of the binder resin.
[0065]
In the present invention, the light-colored toner (cyan and magenta) and the dark-colored toner (cyan and magenta) each contain a charge control agent, and the charge control agent content (Ca) of the light-colored toner and the dark-colored toner The ratio (Ca / Cb) to the content (Cb) of the charge control agent is preferably from 0.5 to 1.0, and more preferably from 0.60 to 0.95. The charging speed of the dark color toner tends to be slower than the charging speed of the light color toner. For this reason, by increasing the charge control agent of the dark color toner, the charging characteristics of both toners are controlled to the same degree, and the effect of suppressing the granularity in the middle density region is further obtained.
[0066]
In the present invention, the dark toner (cyan, magenta) has a toner amount of 1 mg / cm on paper.²The optical density of the solid image is 1.5 to 2.5, and the light cyan toner (cyan, magenta) has a toner amount of 1 mg / cm on paper.²Is preferably 0.82 to 1.35. When the optical density is in the above range, an increase in toner consumption can be further suppressed, and a high-quality image can be obtained more efficiently. The optical density is controlled by controlling the physical properties of the toner from development to fixing, such as the coloring power, developability, and charging characteristics of the toner, by the type of toner material used, the toner manufacturing method, and the image forming process. It is possible to adjust.
[0067]
In the present invention, from the viewpoint of improving transfer efficiency, the light-colored toner (cyan and magenta) and the dark-colored toner (cyan and magenta) are selected from the group consisting of titania, alumina, silica, and double oxides thereof. It is preferable to have the respective inorganic fine powders. The ratio (Sa / Sb) between the value (Sa) of the specific surface area of the light-colored toner measured by the BET method and the value (Sa) of the specific surface area of the dark-colored toner is in the range of 0.5 to 1.0. It is more preferably, and more preferably 0.6 to 0.95. Further, when Sa / Sb is within the above range, the transfer efficiencies of the two light-color toners and the two dark-color toners can be made uniform, whereby the graininess in the medium density region where the toners are mixed in the image is further suppressed. And an even better image can be obtained.
[0068]
The specific surface area of the toner in the above range can be achieved by controlling the specific surface area of the toner particles and the specific surface area, addition amount and mixing strength of the inorganic fine powder added to the toner particles. If the mixing strength is too high, the inorganic fine particles will be embedded in the toner particles, and the transfer efficiency will not be improved much.
[0069]
The specific surface area is determined by using a specific surface area measuring device (for example, Autosorb 1 (manufactured by Yuasa Ionics)) to adsorb nitrogen gas on the sample surface and using the BET multipoint method according to the BET method. The 60% pore radius is determined from a cumulative pore area ratio curve with respect to the pore radius on the desorption side. In Autosorb 1, the calculation of the pore distribution was calculated by Barrett, {Joyner} & Harenda (BJH). J. Perform by the H method.
[0070]
As the binder resin used for the light-color toner and the dark-color toner, a known binder resin can be used.
[0071]
The resin component contained in the toner preferably has a peak in a molecular weight range of 600 to 50,000 in a molecular weight distribution of gel permeation chromatography (GPC) of a tetrahydrofuran (THF) -soluble component. The binder resin preferably contains a low molecular weight component and a high molecular weight component. In the molecular weight distribution of gel permeation chromatography (GPC), the peak of the low molecular weight is preferably in the range of 3,000 to 15,000. This is preferable in that the shape of the toner produced by the pulverization method is controlled by heat and mechanical impact. If the low molecular weight peak exceeds 15,000, the transfer efficiency tends to be insufficiently improved, and if the molecular weight is less than 3,000, fusion tends to occur during the surface treatment of the toner particles.
[0072]
The molecular weight is measured by GPC. As a specific GPC measurement method, a toner is extracted in advance with tetrahydrofuran (THF) for 20 hours using a Soxhlet extractor, and the obtained extract is used as a sample, and A-801, 802, 803, 804 manufactured by Showa Denko KK , 805, 806, and 807 in a column configuration, and measuring the molecular weight distribution using a standard polystyrene resin calibration curve.
[0073]
In the present invention, the binder resin is preferably a resin having a ratio (Mw / Mn) of 2 to 100 between the mass average molecular weight (Mw) and the number average molecular weight (Mn).
[0074]
In the present invention, the glass transition point (Tg) of both light-colored toner and both dark-colored toners is preferably 50 ° C to 75 ° C (more preferably 52 ° C to 70 ° C) from the viewpoint of fixability and storage stability.
[0075]
For the measurement of the glass transition point of the toner, for example, a differential scanning calorimeter of a high-precision internal heat type input compensation type such as DSC-7 manufactured by Perkin Elmer can be used. The measurement is performed according to ASTM D3418-82. In the present invention, a DSC curve measured when the sample is heated once to obtain a pre-history, rapidly cooled, and then heated again at a temperature rate of 10 ° C./min and a temperature range of 0 to 200 ° C. is used. .
[0076]
As the binder resin used in the present invention, for example, polystyrene; styrene-substituted homopolymers such as poly-p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer Styrene-vinyl naphthalene copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl Styrene copolymers such as ether copolymers, styrene-vinyl ethyl ether copolymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-acrylonitrile-indene copolymers Polymer; polyvinyl chloride, Enol resin, natural modified phenolic resin, natural resin modified maleic resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin , Coumarone indene resin and petroleum resin. Crosslinked styrenic resins are also preferred binder resins.
[0077]
As comonomers for the styrene monomer of the styrene copolymer, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, Monocarboxylic acid having a double bond such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide or a substituted product thereof; maleic acid, butyl maleate, methyl maleate, Dicarboxylic acids having a double bond such as dimethyl maleate and substituted products thereof; vinyl esters such as vinyl chloride, vinyl acetate and vinyl benzoate; ethylene-based olefins such as ethylene, propylene and butylene S; vinyl methyl ketone, vinyl ketones such as vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether, vinyl ethers such as vinyl isobutyl ether; such vinyl monomers can be mentioned. These may be used alone or in combination.
[0078]
The binder resin may be cross-linked with a cross-linking agent. As the crosslinking agent, a compound having two or more polymerizable double bonds is used. Examples of the crosslinking agent include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate and 1,3-butanediol dimethacrylate. Divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide, and divinyl sulfone; compounds having three or more vinyl groups; These may be used alone or as a mixture.
[0079]
In the present invention, it is also preferable to include waxes (release agent) in the toner particles from the viewpoint of improving the releasability from the fixing member during fixing and improving the fixing property. Examples of such waxes include paraffin wax and its derivatives, microcrystalline wax and its derivatives, Fischer-Tropsch wax and its derivatives, polyolefin wax and its derivatives, and carnauba wax and its derivatives. Derivatives include oxides, block copolymers with vinyl monomers, and graft-modified products.
[0080]
In addition, long-chain alcohols, long-chain fatty acids, acid amides, ester waxes, ketones, hydrogenated castor oil and derivatives thereof, vegetable waxes, animal waxes, mineral waxes, petrolactam, and the like are sometimes used as waxes. May be.
[0081]
The light-colored cyan toner, the dark-colored cyan toner, the light-colored magenta toner, and the dark-colored magenta toner can be manufactured by a known method. As such a production method, for example, a binder resin, a wax, a pigment or a dye as a colorant, and if necessary, additives such as a charge control agent are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, and the mixture is mixed. Is heated and kneaded using a hot kneader such as a kneader or an extruder.In the case where pigments and the like are later charged, materials such as pigments are added to the melt-kneaded material as necessary, and the kneaded material is cooled. After solidification, pulverization and classification are performed to obtain toner particles. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency.
[0082]
Further, as a method of producing a dark and light cyan toner and a light and dark magenta toner, for example, a method of atomizing a molten mixture into air using a disk or a multi-fluid nozzle described in Japanese Patent Publication No. 56-13945 or the like to obtain a spherical toner, JP-B-36-10231, JP-A-59-53856, and JP-A-59-61842 disclose a method of directly producing a toner using a suspension polymerization method, and a method for producing a monomer. Emulsification represented by a dispersion polymerization method in which a toner is directly produced using an aqueous organic solvent in which a polymer obtained by dissolving is insoluble, or a soap-free polymerization method in which a toner is produced by directly polymerizing in the presence of a water-soluble polar polymerization initiator. Examples of the method include a polymerization method.
[0083]
As a method for producing the light and light cyan toner and the light and light magenta toner, a suspension polymerization method is particularly preferable. Furthermore, a seed polymerization method in which a monomer is further adsorbed onto the polymer particles once obtained and then polymerized using a polymerization initiator is also a preferable production method.
[0084]
It is also preferable to add a polar resin such as a styrene- (meth) acrylic acid copolymer, a styrene-maleic acid copolymer, or a saturated polyester resin to the toner particles.
[0085]
In the suspension polymerization method, for example, a releasing agent composed of a low-softening substance, a coloring agent, a charge control agent, a polymerization initiator, and other additives are added to a polymerizable monomer, and a homogenizer, an ultrasonic disperser or the like is used. Machine to uniformly dissolve or disperse to produce a polymerizable monomer composition, a conventional stirrer, homomixer or homogenizer, the polymerizable monomer composition in an aqueous phase containing a dispersion stabilizer. The polymer particles are dispersed to form droplet particles of the polymerizable monomer composition in the aqueous phase, polymerization is performed, and if necessary, filtration, washing, drying, classification, and the like are performed.
[0086]
In the suspension polymerization method, granulation is preferably performed by adjusting the stirring speed and time so that the droplets of the polymerizable monomer composition have a desired size of the toner particles. After that, stirring may be performed by the action of the dispersion stabilizer to such an extent that the particle state is maintained and settling of the particles is prevented. The polymerization temperature is a temperature of 40 ° C. or higher, generally 50 to 90 ° C.
[0087]
The light and light cyan toner and light and light magenta toner may be a one-component developer or a two-component developer. The one-component developer is formed by mixing the toner particles generated as described above with an external additive such as an inorganic fine powder. The two-component developer is formed by mixing the toner particles generated as described above, an external additive such as an inorganic fine powder, and a carrier.
[0088]
Known inorganic fine powders are used. From the viewpoint of improving charging stability, developability, fluidity, and storage stability, the inorganic fine powder used in the present invention is preferably a silica fine powder, an alumina fine powder, a titania fine powder, or a fine powder of a double oxide thereof. It is preferable to be selected from Particularly, silica fine powder is preferable.
[0089]
As the silica, dry silica produced by vapor phase oxidation of silicon halide or alkoxide, or wet silica produced from alkoxide, water glass, or the like can be used. There are few silanol groups on the surface and inside the silica fine powder.₂O, SO₃ ^2-Dry silica with less production residue such as is preferred. The fumed silica may be a composite fine powder of silica and another metal oxide obtained by using a metal halide such as aluminum chloride and titanium chloride together with a silicon halide in the production process.
[0090]
The inorganic fine powder used in the present invention has a specific surface area of 30 m by nitrogen adsorption measured by the BET method.²/ G or more, especially 50 to 400 m²/ G gives good results. The addition amount of the inorganic fine powder is 0.1 to 8 parts by mass, preferably 0.5 to 5 parts by mass, more preferably 1.0 to 3.0 parts by mass with respect to 100 parts by mass of the toner particles. It is particularly good.
[0091]
The inorganic fine powder used in the present invention preferably has a primary particle size of 30 nm or less.
[0092]
The inorganic fine powder used in the present invention may be, if necessary, a silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, a silane coupling agent, a silane having a functional group, for the purpose of hydrophobicity, charge control, and the like. It is preferable to be treated with a treating agent such as a coupling agent, another organosilicon compound or an organotitanium compound. Two or more treatment agents may be used in combination.
[0093]
In order for the toner to maintain a high charge amount and achieve a low consumption and a high transfer rate, it is more preferable that the inorganic fine powder be treated with at least silicone oil.
[0094]
The inorganic fine powder is preferably an inorganic fine powder obtained by treating a specific coupling agent while hydrolyzing it in the presence of water. In water, a uniform hydrophobic treatment can be performed, there is no coalescence of the particles, and the charge repulsion between the particles due to the treatment works, and the inorganic fine particles are surface-treated in the state of almost primary particles, stabilizing the charge of the toner, It is extremely effective in providing fluidity. As such a preferable inorganic fine powder, for example, a specific coupling agent is treated while being hydrolyzed in the presence of water, has an average particle size of 0.01 to 0.2 μm, and has a hydrophobicity of 20 to 98%. And silica, titanium oxide, or alumina having a light transmittance of 40% or more at 400 nm.
[0095]
In the method of treating the surface while hydrolyzing the coupling agent in the presence of water, a mechanical force for dispersing the inorganic fine particles into the primary particles is applied, so that gasification is performed like chlorosilanes or silazanes. There is no need to use a suitable coupling agent, and a high-viscosity coupling agent or silicone oil, which cannot be used because the particles are coalesced, can also be used.
[0096]
Examples of the coupling agent include a silane coupling agent and a titanium coupling agent. Particularly preferably used is a silane coupling agent, for example, those represented by the following general formula.
RmSiYn (Formula 1)
[Wherein, R represents an alkoxy group, m represents an integer of 1 to 3, Y represents a hydrocarbon group such as an alkyl group, a vinyl group, a glycidoxy group, a methacryl group, and n represents an integer of 1 to 3. Show. ]
Examples of such a silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, Examples include dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-hexadecyltrimethoxysilane, and n-octadecyltrimethoxysilane.
[0097]
More preferably, a trialkoxyalkylsilane coupling agent represented by the following formula is preferable.
C_aH_{2a + 1}-Si (OC_bH_{2b + 1})₃(Chemical 2)
[Wherein, a represents an integer of 4 to 12, and b represents an integer of 1 to 3. ]
When a is smaller than 4 in the above formula, the treatment becomes easy, but the hydrophobicity may decrease. When a is larger than 12, the hydrophobicity is sufficient, but the particles are easily united. If b is larger than 3, the reactivity may decrease. a is 4 to 12, preferably 4 to 8, and b is 1 to 3, preferably 1 or 2.
[0098]
The amount of the silane coupling agent to be treated is 1 to 50 parts by mass, preferably 3 to 40 parts by mass, per 100 parts by mass of the inorganic fine powder. The hydrophobicity is preferably from 20 to 98%, more preferably from 30 to 90%, and even more preferably from 40 to 80%. If the degree of hydrophobicity is less than 20%, the charge amount after long-term storage under high humidity tends to decrease, and if the degree of hydrophobicity exceeds 98%, the toner tends to charge up under low humidity.
[0099]
The particle diameter of the hydrophobized inorganic fine powder is preferably 0.01 to 0.2 μm from the viewpoint of improving the fluidity of the toner particles. When the particle diameter is larger than 0.2 μm, the uniformity of the charging of the toner is reduced, and as a result, toner scattering and fogging are likely to occur. When the thickness is less than 0.01 μm, the toner particles are easily embedded on the surface of the toner particles, the toner is easily deteriorated, and the durability is easily lowered. The particle size of the additive means an average particle size obtained by observing the surface of the toner (for example, 20,000 times) with an electron microscope.
[0100]
In the present invention, in order to improve transferability and cleaning performance, in addition to the inorganic fine powder, the primary particle diameter further exceeds 30 nm (preferably, the specific surface area is 50 m²/ G), more preferably 50 nm or more (preferably having a specific surface area of 30 m²/ G) is also a preferred embodiment. Preferred examples of such spherical particles include spherical silica particles, spherical polymethylsilsesquioxane particles, and spherical resin particles.
[0101]
In the present invention, other additives may be used within a range that does not cause a substantial adverse effect. Examples of such other additives include lubricant powders such as fluororesin powder, zinc stearate powder, calcium stearate particles, and polyvinylidene fluoride powder; abrasives such as cerium oxide powder, silicon carbide powder, and strontium titanate powder; Fluidity-imparting agents such as aluminum oxide powder; anti-caking agents; conductivity-imparting agents such as carbon black powder, zinc oxide powder and tin oxide powder; organic fine particles and inorganic fine particles having a polarity opposite to that of toner particles.
[0102]
From the viewpoint of durability when mixed with the toner particles, the additive preferably has a particle diameter of 1/10 or less of the weight average particle diameter of the toner particles. The particle size of the additive means an average particle size of the toner particles (for example, 20,000 times) obtained by observing the surface of the particles with an electron microscope.
[0103]
These additives are preferably used in an amount of 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, based on 100 parts by mass of the toner particles. The additives may be used alone or in combination of two or more. More preferably, the additive has been subjected to a hydrophobic treatment.
[0104]
The external additive coverage on the surface of the toner particles is preferably from 5 to 99%, more preferably from 10 to 99%. The external additive coverage on the toner particle surface is determined by randomly sampling 100 toner particle images (for example, 20,000 times) using FE-SEM (S-800) manufactured by Hitachi, Ltd., and the image information is transmitted via an interface. Can be obtained by introducing an image analysis device (Luzex3) manufactured by Nireco Co., Ltd., performing analysis, and calculating.
[0105]
As the carrier, known carriers such as a carrier made of a magnetic material, a carrier having a structure in which the surface of a magnetic material is coated with a resin, and a carrier having a structure in which a magnetic material is dispersed in resin particles can be used. As the magnetic material, a known magnetic material containing iron oxide as a main component can be used. As the resin, for example, the binder resin described above can be used.
[0106]
In the image forming method of the present invention described later, a yellow toner, a black toner, a magenta toner when used in combination with a dark and light cyan toner, or a dark and light color used in forming a full color image. For the cyan toner when used in combination with the magenta toner described above, the above-described binder resin, charge control agent, and the like can be used except that the colorant is different. Naturally, the dark and light cyan toners may be used in combination with the dark and light magenta toners.
[0107]
Examples of the yellow colorant include compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 168, 174, 176, 180, 181 and 191 are preferably used.
[0108]
As the magenta colorant, in addition to those usable for dark and light magenta toners, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 81: 1, 166, 169, 184, 185, 206 can also be used.
[0109]
Examples of the black colorant include carbon black and those toned to black using the yellow, magenta, and cyan colorants described above.
[0110]
These colorants can be used alone or as a mixture or in the form of a solid solution. The colorant is selected from the viewpoints of hue angle, saturation, lightness, weather resistance, OHP transparency, and dispersibility in toner particles. The amount of the colorant varies depending on the type of the colorant, but is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the binder resin.
[0111]
As the black colorant, a known magnetic substance can be used. Examples of such a magnetic material include metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum, and silicon. Among them, those containing iron oxide as a main component, such as ferric oxide and γ-iron oxide, are preferable. The magnetic material may contain a metal element such as a silicon element or an aluminum element from the viewpoint of controlling the chargeability of the toner. The magnetic material has a BET specific surface area of 2 to 30 m by a nitrogen adsorption method.²/ G, especially 3 to 28 m²/ G, and preferably a Mohs hardness of 5 to 7.
[0112]
Examples of the shape of the magnetic body include an octahedron, a hexahedron, a sphere, a needle, and a scale. Those having low anisotropy, such as octahedron, hexahedron, and sphere, are preferable for increasing the image density. The average particle size of the magnetic material is preferably 0.05 to 1.0 μm, more preferably 0.1 to 0.6 μm, and further preferably 0.1 to 0.4 μm.
[0113]
The addition amount of the magnetic material is preferably 30 to 200 parts by mass, more preferably 40 to 200 parts by mass, and even more preferably 50 to 150 parts by mass with respect to 100 parts by mass of the binder resin. . If the amount is less than 30 parts by mass, in a developing device that uses a magnetic force to transport the toner, the transportability is reduced, and the developer layer on the developer carrier tends to be uneven, resulting in image unevenness. The image density tends to decrease due to the increase. On the other hand, if it exceeds 200 parts by mass, a problem tends to occur in the fixing property.
[0114]
Next, a method for producing the toner used in the present invention will be described.
[0115]
In the present invention, the effect of the present invention can be enhanced by using a toner in which part or all of the toner particles are formed by a polymerization method. In particular, with respect to toner particles in which a portion of the surface of the toner particles is formed by a polymerization method, it is possible to obtain a toner particle whose surface is considerably smoothed.
[0116]
The use of toner particles formed by polymerization of the shell portion of the core / shell structure can improve blocking resistance without impairing excellent fixability, and can be used as a bulk polymerized toner having no core portion. In comparison, there is an advantage that the residual monomer can be easily removed in the post-treatment step after the polymerization step.
[0117]
As the main component of the core portion, a low softening point substance (the above-mentioned wax or release agent) is preferable, and the main maximum peak value of the endothermic peak measured according to ASTM D3418-8 shows 40 to 90 ° C. Compounds are preferred. If the maximum peak is less than 40 ° C., the self-cohesive force of the low softening point substance becomes weak, and as a result, the high-temperature offset resistance decreases. On the other hand, when the maximum peak exceeds 90 ° C., the fixing temperature increases.
[0118]
For measurement of the temperature of the maximum peak value of the low softening point substance, for example, DSC-7 manufactured by Perkin Elemer Corporation is used. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of the calorific value uses the indium heat of fusion. An aluminum pan was used as a sample, an empty pan was set as a control, and the temperature was raised at a rate of 10 ° C./min. Perform the measurement with.
[0119]
As the low softening point substance, wax as described above can be used, and examples thereof include paraffin wax, polyolefin wax, Fischer-Tropsch wax, amide wax, higher fatty acid, ester wax, and derivatives or graft / block compounds thereof. Can be
[0120]
The low softening point substance is preferably added to the toner particles in an amount of 5 to 30 parts by mass per 100 parts by mass of the binder resin. If the addition is less than 5 parts by mass, the above-mentioned removal of the residual monomer is burdened. If the addition exceeds 30 parts by mass, toner particles tend to coalesce during granulation even in the production by polymerization method, and the particle size distribution Is easy to generate.
[0121]
Examples of the outer shell resin constituting the shell portion in the core / shell structure include a styrene- (meth) acryl copolymer, a polyester resin, an epoxy resin, and a styrene-butadiene copolymer. In a method for directly obtaining a toner by a polymerization method, styrene; styrene-based monomers such as o- (m-, p-) methylstyrene and m- (p-) ethylstyrene; methyl (meth) acrylate; ) Ethyl acrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, (meth) (Meth) acrylate monomers such as 2-ethylhexyl acrylate, dimethylaminoethyl (meth) acrylate, and diethylaminoethyl (meth) acrylate; butadiene, isoprene, cyclohexene, (meth) acrylonitrile, acrylamide An ene monomer such as the following is preferably used.
[0122]
These may be used alone or in a single amount such that the theoretical glass transition temperature (Tg) described in the published Polymer Handbook, 2nd edition, III-P139-192 (manufactured by John Wiley & Sons) is 40-75 ° C. The bodies are appropriately mixed and used for polymerization. If the theoretical glass transition temperature is lower than 40 ° C., problems arise in terms of the storage stability of the toner and the durability stability of the developer. In the case of the toner for use, the color mixing property of each color toner may be reduced, and the color reproducibility may be reduced. Further, the transparency of the OHP image may be significantly reduced.
[0123]
The molecular weight of the outer shell resin is measured by gel permeation chromatography (GPC). As a specific GPC measurement method, a toner is extracted in advance with a toluene solvent using a Soxhlet extractor for 20 hours, and then toluene is distilled off using a rotary evaporator. After adding an organic solvent that cannot be dissolved, for example, chloroform, etc., and sufficiently washing the solution, a solution obtained by filtering a solution dissolved in THF (tetrahydrofuran) through a solvent-resistant membrane filter having a pore diameter of 0.3 μm is sampled, for example. A method of measuring using 150C manufactured by Waters, Inc. may be mentioned. The column configuration in such a measurement may be a configuration in which A-801, 802, 803, 804, 805, 806, 807 manufactured by Showa Denko are connected, and a molecular weight distribution can be obtained using a calibration curve of a standard polystyrene resin. In the present invention, the outer shell resin has a number average molecular weight (Mn) of 5,000 to 1,000,000 and a ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 2 to 100. Is preferred.
[0124]
In the case of producing toner particles having a core / shell structure, it is particularly preferable to add a polar resin in addition to the outer shell resin in order to satisfactorily include the low softening point substance in the outer shell resin. As the polar resin, a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a saturated polyester resin, and an epoxy resin are preferably used. It is particularly preferable that the polar resin does not contain an unsaturated group capable of reacting with the outer shell resin or the monomer in the molecule. If a polar resin having an unsaturated group is included, a cross-linking reaction occurs with the monomer that forms the outer shell resin layer. Is disadvantageous and is not preferred.
[0125]
In the toner used in the present invention, an outermost resin layer may be further provided on the surface of the toner particles, and the polar resin may be used as the outermost resin layer.
[0126]
The glass transition temperature of the outermost shell resin layer is designed to be equal to or higher than the glass transition temperature of the outer shell resin layer in order to further improve blocking resistance, and further, the glass transition temperature is crosslinked so as not to impair fixability. Is preferred. The outermost shell resin layer preferably contains a polar resin and a charge control agent for improving the chargeability.
[0127]
The method of providing the outermost shell layer is not particularly limited, but, for example, (1) a polar resin, a charge control agent, a cross-linking agent, if necessary, in the reaction system in the second half or after the end of the polymerization reaction. A method in which a monomer in which the compound is dissolved and dispersed is added, the mixture is adsorbed on polymer particles, and a polymerization initiator is added to perform polymerization, or (2) a monomer containing a polar resin, a charge control agent, a cross-linking agent, etc. A method of adding emulsion polymerized particles or soap-free polymerized particles to the reaction system, and aggregating the polymerized particles on the surface of the polymerized particles and fixing the particles by heat or the like, if necessary; (3) if necessary, a polar resin and a charge control agent And a method in which emulsion polymerized particles or soap-free polymerized particles comprising a monomer containing a crosslinking agent or the like are mechanically fixed to the surface of toner particles in a dry manner.
[0128]
In the present invention, a suspension polymerization method under normal pressure or under pressure is particularly preferable, in which a fine particle toner having a sharp particle size distribution and a particle size of 4 to 8 μm can be obtained relatively easily. As a specific method for encapsulating the low softening point substance, the polarity of the material in the aqueous medium is set to be smaller for the low softening point substance than for the main monomer, and a small amount of a large polar resin or monomer is used. And then polymerizing. According to such a method, a toner having a so-called core / shell structure in which a material having a low softening point is coated with an outer shell resin can be obtained.
[0129]
In the above-mentioned production method, the particle size distribution control and the particle size of the toner are controlled by changing the type and amount of the hardly water-soluble inorganic salt or the dispersant acting as a protective colloid, and the mechanical device conditions (for example, the rotor peripheral speed, , Stirring conditions in the shape of a stirring blade or the shape of a container) or the solid content concentration in an aqueous solution.
[0130]
As a specific method for measuring the tomographic plane of the toner particles, the toner particles are sufficiently dispersed in a room temperature curable epoxy resin, and then cured in an atmosphere at a temperature of 40 ° C. for 2 days. Ruthenium trioxide and, if necessary, osmium tetroxide are used in combination, and then dyed, a flaky sample is cut out using a microtome equipped with diamond teeth, and the tomographic morphology of the toner is measured using a transmission electron microscope (TEM). No. In the measurement of the tomographic plane, it is preferable to use a ruthenium tetroxide staining method in order to provide a contrast between the materials by utilizing a slight difference in crystallinity between the low softening point material and the resin constituting the outer shell. .
[0131]
Next, the image forming method of the present invention will be described.
[0132]
The image forming method of the present invention is a method of forming a toner image by superimposing a light cyan toner image and a dark cyan toner image and / or superimposing a light magenta toner image and a dark magenta toner image. A light cyan toner, a dark cyan toner, a light magenta toner and a dark magenta toner are used.
[0133]
According to such an image forming method, from a low density region to a high density region, graininess and roughness can be reduced, and a higher quality cyan image or magenta image can be formed at least, and thus a higher quality image can be formed. A full-color image can be formed.
[0134]
i) As a step of forming an electrostatic image, a step of forming an electrostatic image for cyan developed with cyan toner, a step of forming an electrostatic image for magenta developed with magenta toner, and a step of developing with a yellow toner Forming a yellow electrostatic image, and forming a black electrostatic image developed with black toner, and ii) forming a cyan electrostatic image with cyan toner as a toner image forming step. Developing to form a cyan toner image, developing a magenta electrostatic image with magenta toner to form a magenta toner image, and developing the yellow electrostatic image with yellow toner to form a yellow toner image And a step of developing the black electrostatic image with a black toner to form a black toner image, and iii) a transferring step. A method of transferring a cyan toner image, a magenta toner image, a yellow toner image, and a black toner image to a transfer material to form a full-color toner image on the transfer material, wherein the cyan toner and / or the magenta toner When the process is divided into a process using a dark color toner and a process using a light color toner, it is possible to reduce the graininess and roughness caused by the cyan image or the magenta image, and obtain a high-quality full-color image. be able to.
[0135]
The step of forming the electrostatic charge image is a step of separately forming an electrostatic charge image corresponding to the toner used in the present image forming method. The formation of an electrostatic charge image corresponding to each toner in full-color image formation can be performed by a known method.
[0136]
The step of forming the electrostatic image is a step of forming a first electrostatic image developed with a light cyan toner or a dark cyan toner, and a step of forming a second electrostatic image developed with the other cyan toner. Forming step. Alternatively, the method includes a step of forming a first electrostatic image developed with the light magenta toner or the dark magenta toner, and a step of forming a second electrostatic image developed with the other magenta toner.
[0137]
In the cyan image in the output image, similarly to the image of the other colors, input signals such as the image density and luminance of the input cyan image are subjected to appropriate calculation and correction in accordance with the gradation and the like in image formation. And converted into an output signal, and formed based on the output signal. In the present invention, the intensity of the output signal of the light cyan toner and the intensity of the output signal of the dark cyan toner are set in advance in accordance with the intensity of the input signal, and the intensity in the output signal of each cyan toner is set based on this setting. Is determined, and a first electrostatic image and a second electrostatic image are formed. The same applies to the case where the light color magenta toner and the dark color magenta toner are used.
[0138]
The setting of the intensity of the output signal cannot be unconditionally described because it includes elements that are difficult to simply digitize, such as human visual characteristics, but for example, as shown in FIG. In a small area, a setting can be exemplified in which the intensity of the output signal of the light cyan toner is increased, and the intensity of the output signal of the dark cyan toner is increased as the intensity of the input signal increases.
[0139]
The step of forming the toner image is a step of developing the electrostatic image formed on the electrostatic image carrier with a corresponding toner to form a toner image. The step of forming a toner image is performed by a known method according to the type of toner to be used and the like, and is performed by a suitably selected developing device.
[0140]
In the transferring step, each toner image formed on the electrostatic image carrier is transferred from the electrostatic image carrier to a transfer material, and a toner image in which all the formed toner images are superimposed is transferred. This is the step of forming the material. The transfer of the toner image to the transfer material is not particularly limited, and can be performed by a known method. The transfer of the toner image to the transfer material may be a method of directly transferring from the electrostatic image carrier to the transfer material, or a method of transferring from the electrostatic image carrier to the transfer material via the intermediate transfer body. There may be. In the method of transferring from the electrostatic image carrier to the transfer material via the intermediate transfer member, the toner image primarily transferred to the intermediate transfer member and the toner image subsequently transferred from the electrostatic image carrier are overlapped. Transcribed.
[0141]
The toner image on the transfer material is fixed on the transfer material by using a known heat and pressure fixing device. As the fixing step, a heating and pressing step is preferable.
[0142]
In the present invention, in addition to the above-described steps, a method including various steps such as a cleaning step of removing toner remaining on the electrostatic image carrier after transfer from the electrostatic image carrier may be used. Further, in the present invention, an image forming method in which an electrostatic image corresponding to each toner is formed on one electrostatic image carrier and the process from formation to transfer of the electrostatic image for each toner may be repeated. Alternatively, an image forming method may be used in which a plurality of electrostatic image carriers corresponding to the respective toners are used, and the processes from formation to transfer of the electrostatic image for each toner are individually performed for each electrostatic image carrier. Further, in the present invention, the order of the formation of the electrostatic image, the formation of the toner image, and the transfer to the transfer material is not particularly limited.
[0143]
In the electrostatic image carrier used in the present invention, the contact angle of water on the surface of the electrostatic image carrier is preferably 85 degrees or more (preferably 90 degrees or more). When the contact angle with water is 85 degrees or more, the transfer rate of the toner image is improved, and filming of the toner hardly occurs. The contact angle of water on the surface of the electrostatic image carrier can be measured using, for example, a drop-type contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.).
[0144]
Preferred examples of the electrostatic image carrier used in the present invention will be described below. As is well known, the electrostatic image carrier used in the present invention includes a conductive substrate, a photosensitive layer formed on the conductive substrate, and, if necessary, the protective layer (surface layer). The photosensitive layer may be formed by laminating layers each having a specific function, such as a charge generation layer and a charge transport layer.
[0145]
Examples of the material for forming the conductive substrate include metals such as aluminum and stainless steel; plastics having a coating layer of an aluminum alloy and an alloy such as indium oxide-tin oxide alloy; paper and plastic impregnated with conductive particles; And a plastic having: As the substrate, a cylindrical cylinder and a film are used.
[0146]
On these conductive substrates, the purpose is to improve the adhesion of the photosensitive layer, improve the coating properties, protect the substrate, cover defects on the substrate, improve the charge injection property from the substrate, and protect the photosensitive layer against electrical breakdown. An undercoat layer may be provided.
[0147]
The undercoat layer is made of polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, nitrocellulose, ethylene-acrylic acid copolymer, polyvinyl butyral, phenol resin, casein, polyamide, copolymer nylon, glue, gelatin, polyurethane , Made of a material such as aluminum oxide. The film thickness is usually 0.1 to 10 μm, preferably 0.1 to 3 μm.
[0148]
The charge generation layer is made of an organic material such as an azo pigment, a phthalocyanine pigment, an indigo pigment, a perylene pigment, a polycyclic quinone pigment, a squarylium pigment, a pyrylium salt, a thiopyrylium salt, or a triphenylmethane pigment; A charge-generating substance consisting of an inorganic substance such as porous silicon; is dispersed in an appropriate binder, and is formed by coating or vapor deposition.
[0149]
As the binder, a wide range of binder resins can be selected. For example, a polycarbonate resin, a polyester resin, a polyvinyl butyral resin, a polystyrene resin, an acrylic resin, a methacryl resin, a phenol resin, a silicone resin, an epoxy resin, and a vinyl acetate resin are exemplified. The amount of the binder contained in the charge generation layer is 80% by mass or less, and preferably 0 to 40% by mass. The thickness of the charge generation layer is preferably 5 μm or less, particularly preferably 0.05 to 2 μm.
[0150]
The charge transport layer has a function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting them. The charge transporting layer is formed by dissolving a charge transporting substance in a solvent together with a binder resin if necessary, and applying the solution. The thickness is generally 5 to 40 μm.
[0151]
As the charge transporting substance, a polycyclic aromatic compound having a structure such as biphenylene, anthracene, pyrene, or phenanthrene in a main chain or a side chain; a nitrogen-containing cyclic compound such as indole, carbazole, oxadiazole, or pyrazoline; a hydrazone compound; Styryl compounds; inorganic compounds such as selenium, selenium-tellurium, amorphous silicon and cadmium sulfide.
[0152]
Examples of the binder resin for dispersing these charge transporting substances include resins such as polycarbonate resin, polyester resin, polymethacrylate, polystyrene resin, acrylic resin, and polyamide resin; and organic photoconductive resins such as poly-N-vinylcarbazole and polyvinylanthracene. Polymer.
[0153]
Further, a protective layer may be provided as a surface layer. Examples of the resin of the protective layer include polyester, polycarbonate, acrylic resin, epoxy resin, phenol resin, and those obtained by curing these resins with a curing agent. These are used alone or in combination of two or more.
[0154]
Conductive fine particles may be dispersed in the resin of the protective layer. Examples of the conductive fine particles include metal or metal oxide fine particles. Preferably, there are fine particles of a material such as zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin oxide-coated titanium oxide, tin-coated indium oxide, antimony-coated tin oxide, and zirconium oxide. These may be used alone or in combination of two or more.
[0155]
Generally, when the conductive fine particles are dispersed in the protective layer, it is preferable that the particle diameter of the conductive fine particles is smaller than the wavelength of the incident light in order to prevent scattering of the incident light by the conductive fine particles. The particle size of the conductive fine particles dispersed in the protective layer is preferably 0.5 μm or less. The content in the protective layer is preferably from 2 to 90% by mass, more preferably from 5 to 80% by mass, based on the total mass of the protective layer. The thickness of the protective layer is preferably from 0.1 to 10 μm, more preferably from 1 to 7 μm.
[0156]
The coating of the surface layer can be performed by spray coating, beam coating or penetrating coating of the resin dispersion.
[0157]
When the one-component developing method is used in the present invention, in order to obtain high image quality, the toner having a layer thickness smaller than the closest distance (between SD) between the toner carrier and the electrostatic image carrier is obtained on the toner carrier. Is preferably developed in a developing step of applying an alternating electric field and performing development.
[0158]
The surface roughness of the toner carrier used in the present invention is preferably in the range of 0.2 to 3.5 μm in JIS center line average roughness (Ra). When Ra is less than 0.2 μm, the charge amount on the toner carrier tends to increase, and the developability tends to decrease. When Ra exceeds 3.5 μm, the toner coat layer on the toner carrier tends to be uneven. More preferably, the surface roughness is 0.5 to 3.0 μm.
[0159]
Further, since the toner used in the present invention has a high charging ability, it is preferable to control the total charge amount of the toner during development. The surface of the toner carrier is preferably covered with a resin layer in which conductive fine particles and a lubricant are dispersed.
[0160]
Examples of the conductive fine particles contained in the resin layer covering the surface of the toner carrier include conductive metal oxides such as carbon black, graphite, and conductive zinc oxide, and metal double oxides. These are preferably used alone or in combination of two or more. Examples of the resin in which the conductive fine particles are dispersed include a phenolic resin, an epoxy resin, a polyamide resin, a polyester resin, a polycarbonate resin, a polyolefin resin, a silicone resin, a fluorine resin, a styrene resin, and an acrylic resin. A resin such as a resin is used. Particularly, a thermosetting or photocurable resin is preferable.
[0161]
It is particularly preferable that the toner is regulated by a member that regulates the toner on the toner carrier by an elastic member that is in contact with the toner carrier via the toner from the viewpoint of uniformly charging the toner. In the present invention, it is more preferable from the viewpoint of environmental protection that the charging member and the transfer member are in contact with the electrostatic image carrier so that ozone is not generated.
[0162]
Next, the image forming method of the present invention will be described more specifically with reference to FIG. In FIG. 10, A is a printer unit, and B is an image reading unit (image scanner) mounted on the printer unit A.
[0163]
In the image reading section B, reference numeral 20 denotes a fixed original platen glass. An original G is placed on the upper surface of the original platen glass 20 with the surface to be copied facing down, and an original plate (not shown) is placed thereon. Set it over. An image reading unit 21 includes a document irradiation lamp 21a, a short focus lens array 21b, a CCD sensor 21c, and the like.
[0164]
When a copy button (not shown) is pressed, the image reading unit 21 moves forward from the home position on the left side of the original table glass 20 to the right side along the lower surface of the original table glass 20 when the copy button (not shown) is pressed. When a predetermined reciprocating end point is reached, the motor is driven backward and returned to the initial home position.
[0165]
In the forward drive process of the image reading unit 21, the downward image surface of the document G placed on the document table glass 20 is sequentially illuminated and scanned from the left side to the right side by the document irradiating lamp 21a. The light reflected from the document surface is imaged and incident on the CCD sensor 21c by the short focus lens array 21b.
[0166]
The CCD sensor 21c includes a light receiving unit, a transfer unit, and an output unit (not shown). The light signal is converted into a charge signal in the light receiving unit, and the charge signal is sequentially output from the transfer unit in synchronization with a clock pulse. The charge signal is converted to a voltage signal at an output unit, amplified, reduced in impedance, and output. The analog signal thus obtained is converted into a digital signal by well-known image processing and output to the printer unit A. That is, the image reading section B photoelectrically reads the image information of the document G as a time-series electric digital pixel signal (image signal).
[0167]
FIG. 12 shows a block diagram of the image processing. In the figure, an image signal output from the CCD sensor 21c is input to an analog signal processing unit 51, where gain and offset are adjusted, and then, for example, 8 bits ( (0 to 255 levels: 256 gradations), and the shading correction unit 53 uses a signal obtained by reading a reference white plate (not shown) for each color in a CCD sensor cell group arranged in a line. In order to eliminate the variation in sensitivity of each sensor, a known shading correction for optimizing a gain corresponding to each CCD sensor cell is performed.
[0168]
The line delay unit 54 corrects a spatial shift included in the image signal output from the shading correction unit 53. This spatial shift is caused by the line sensors of the CCD sensor 21c being arranged at a predetermined distance from each other in the sub-scanning direction. Specifically, the spatial deviation is corrected by line-delaying each of the R (red) and G (green) color component signals in the sub-scanning direction with reference to the B (blue) color component signal, and To synchronize the phases.
[0169]
The input masking unit 55 converts the color space of the image signal output from the line delay unit 54 into an NTSC standard color space by a matrix operation represented by the following equation. In other words, the color space of each color component signal output from the CCD sensor 21c is determined by the spectral characteristics of the filter of each color component, but the input masking unit 55 converts this into the NTSC standard color space.
[0170]
(Equation 6)

[0171]
The LOG conversion unit 56 is configured by, for example, a look-up table (LUT) including a ROM or the like, and converts the RGB luminance signal output from the input masking unit 55 into a CMY density signal. The line delay memory 57 stores the image signal output from the LOG conversion unit 56 during a period (line delay) during which the black character determination unit (not shown) generates the control signals UCR, FILTER, SEN, and the like from the output of the input masking unit 55. Delay.
[0172]
The masking / UCR unit 58 extracts the black component signal K from the image signal output from the line delay memory 57, and further performs a matrix operation for correcting the color turbidity of the recording color material of the printer unit, and the YMCK performs a matrix operation on the signal. For example, an 8-bit color component image signal is output in the order of M, C, Y, and K for each reading operation of the reader unit. The matrix coefficients used for the matrix operation are set by a CPU (not shown).
[0173]
Next, based on the obtained 8-bit color component image signal Data, a process of determining the recording rates Rn and Rt of dark dots and light dots with reference to FIG. For example, if the input gradation data Data is 100/255, the recording rate Rt of light dots is determined as 250/255, and the recording rate Rn of dark dots is determined as 40/255. Note that the recording rate is indicated by an absolute value with 255 being 100%.
[0174]
The γ correction unit 59 performs density correction on the image signal output from the masking / UCR unit 58 in order to match the image signal with the ideal gradation characteristics of the printer unit. The output filter (spatial filter processing unit) 60 performs edge enhancement or smoothing processing on the image signal output from the γ correction unit 59 according to a control signal from the CPU.
[0175]
The LUT 61 is for matching the density of the original image with the density of the output image, and is composed of, for example, a RAM, and the conversion table is set by the CPU. A pulse width modulator (PWM) 62 outputs a pulse signal having a pulse width corresponding to the level of the input image signal, and the pulse signal is input to a laser driver 41 that drives a semiconductor laser (laser light source).
[0176]
In addition, a pattern generator (not shown) is mounted on this image forming apparatus, and a gradation pattern is registered, so that a signal can be directly passed to the pulse width modulator 62.
[0177]
FIG. 13 is a schematic configuration diagram showing the exposure apparatus 3. The exposure device 3 forms an electrostatic image by performing laser scanning exposure L on the surface of the electrostatic image carrier 1 based on an image signal input from the image reading unit 21. When the surface of the electrostatic image carrier 1 is subjected to laser scanning exposure L by the exposure device 3, first, the solid-state laser element 25 is caused to emit light by a light emission signal generator 24 at a predetermined timing based on an image signal input from the image reading unit 21. Brightening (ON / OFF). Then, the laser light, which is an optical signal emitted from the solid-state laser element 25, is converted into a substantially parallel light beam by a collimator lens system 26, and furthermore, an electrostatic charge image is formed by a rotating polygon mirror 22, which rotates at high speed in the direction of arrow c. By scanning the carrier 1 in the direction of the arrow d (longitudinal direction), a laser spot is formed on the surface of the electrostatic image carrier 1 by the fθ lens group 23 and the reflection mirror (see FIG. 10). By such laser scanning, an exposure distribution for the scanning is formed on the surface of the electrostatic image carrier 1. Further, by scrolling a predetermined amount vertically with respect to the surface of the electrostatic image carrier 1 for each scan. Thus, an exposure distribution according to the image signal is obtained on the surface of the electrostatic image carrier 1.
[0178]
That is, the light of the solid-state laser element 25, which is turned on / off in response to an image signal, is applied to the uniformly charged surface (for example, charged to −700 V) of the electrostatic image carrier 1 by the rotating polygon mirror 22 that rotates at high speed. , An electrostatic image of each color corresponding to the scanning exposure pattern is sequentially formed on the surface of the electrostatic image carrier 1.
[0179]
As shown in FIG. 14, the developing device 4 includes developing units 411a, 411b, 412, 413, 414, and 415. These developing units include a developer having a light cyan toner, a developer having a dark cyan toner, a developer having a light magenta toner, a developer having a dark magenta toner, a developer having a yellow toner, and Developers with black toner have been introduced. Each of the introduced developers develops an electrostatic image formed on the electrostatic image carrier 1 by a magnetic brush developing method, and a toner image of each color is formed on the electrostatic image carrier 1. In the present invention, a dark / light cyan toner and a dark / light magenta toner may be used in combination, or only one magenta toner may be used, or only one cyan toner may be used. When five types of developers are used, they may be introduced into any of the six types of developing devices described above. Further, a developer having a light color toner having another color, a special color toner such as green, orange or white, a colorless toner containing no colorant, or the like may be introduced into the remaining one developing device. Further, the order of colors to be introduced into the developing device does not matter. As these developing devices, a two-component developing device as shown in FIG. 11 is one of preferred examples.
[0180]
In FIG. 11, the two-component developing device includes a developing sleeve 30 that is driven to rotate in the direction of arrow e. In the developing sleeve 30, a magnet roller 31 is fixedly arranged. The developing container 32 is provided with a regulating blade 33 for forming a thin layer of the developer T on the surface of the developing sleeve 30.
[0181]
The inside of the developing container 32 is divided into a developing chamber (first chamber) R1 and a stirring chamber (second chamber) R2 by a partition 36, and a toner hopper 34 is disposed above the stirring chamber R2. I have. Conveying screws 37 and 38 are provided in the developing chamber R1 and the stirring chamber R2, respectively. The toner hopper 34 is provided with a supply port 35, and when toner is supplied, the toner t is dropped and supplied through the supply port 35 into the stirring chamber R2.
[0182]
On the other hand, the developer T in which the toner particles and the magnetic carrier particles are mixed is accommodated in the developing chamber R1 and the stirring chamber R2.
[0183]
The developer T in the developing chamber R <b> 1 is transported in the longitudinal direction of the developing sleeve 30 by rotating the transport screw 37. The developer T in the stirring chamber R <b> 2 is transported in the longitudinal direction of the developing sleeve 30 by rotation of the transport screw 38. The developer transport direction by the transport screw 38 is opposite to that by the transport screw 37.
[0184]
The partition 36 is provided with openings (not shown) on the near side and the back side, which are perpendicular to the plane of the paper, respectively, and the developer T conveyed by the conveying screw 37 is conveyed from one of the openings. The developer T delivered to the screw 38 and transported by the transport screw 38 is delivered to the transport screw 37 from another one of the openings. The toner is charged to a polarity for developing the latent image by friction with the magnetic particles.
[0185]
A developing sleeve 30 made of a non-magnetic material such as aluminum or non-magnetic stainless copper is provided in an opening provided in a portion of the developing container 32 close to the electrostatic image carrier 1, and is arranged in a direction indicated by an arrow e (counterclockwise). ) To carry and transport the developer T in which the toner and the carrier are mixed to the developing unit C. The magnetic brush of the developer T carried on the developing sleeve 30 contacts the electrostatic image carrier 1 rotating in the direction of arrow c (clockwise) in the developing section C, and the electrostatic image is developed in the developing section C. .
[0186]
A vibration bias voltage in which a DC voltage is superimposed on an AC voltage is applied to the developing sleeve 30 by a power supply (not shown). The dark portion potential (non-exposed portion potential) and the light portion potential (exposed portion potential) of the latent image are located between the maximum value and the minimum value of the vibration bias potential. As a result, an alternating electric field whose direction alternates is formed in the developing section C. In this alternating electric field, the toner and the carrier vibrate violently, and the toner shakes off the electrostatic restraint on the developing sleeve 30 and the carrier, and adheres to the bright portion on the surface of the electrostatic image carrier 1 corresponding to the latent image. .
[0187]
The difference (peak-to-peak voltage) between the maximum value and the minimum value of the oscillation bias voltage is preferably 1 to 5 kV (for example, a rectangular wave of 2 kV), and the frequency is preferably 1 to 10 kHz (for example, 2 kHz). Further, the waveform of the oscillation bias voltage is not limited to a rectangular wave, but may be a sine wave, a triangular wave, or the like.
[0188]
The DC voltage component has a value between the dark portion potential and the bright portion potential of the electrostatic charge image, and is a value closer to the dark portion potential than the minimum bright portion potential in absolute value. This is preferable for preventing fog toner from adhering to the dark portion potential region. Specific values of the potential of the electrostatic image and the developing bias include, for example, a dark portion potential of -700 V, a bright portion potential of -200 V, and a DC component of the developing bias of -500 V. The minimum gap between the developing sleeve 30 and the electrostatic image carrier 1 (the minimum gap position is in the developing section C) is preferably 0.2 to 1 mm (for example, 0.5 mm).
[0189]
The amount of the developer T regulated by the regulating blade 33 and conveyed to the developing unit C is determined by the developing sleeve of the magnetic brush of the developer T formed by the magnetic field in the developing unit C by the developing magnetic pole S1 of the magnet roller 31. An amount such that the height on the surface 30 is 1.2 to 3 times the minimum gap value between the developing sleeve 30 and the electrostatic image carrier 1 with the electrostatic image carrier 1 removed (for example, It is preferably 700 μm for the minimum gap value exemplified above.
[0190]
The developing magnetic pole S1 of the magnet roller 31 is arranged at a position facing the developing section C, and a magnetic field of the developer T is formed by the developing magnetic field formed by the developing magnetic pole S1 in the developing section C. The electrostatic image of the dot distribution is developed by contacting the charge image carrier 1. At this time, both the toner adhering to the brush (brush) of the magnetic carrier and the toner adhering to the surface of the sleeve instead of the spike transfer to the exposed portion of the electrostatic image to develop the electrostatic image.
[0191]
The peak value of the strength (magnetic flux density in a direction perpendicular to the surface of the developing sleeve 30) of the developing magnetic field by the developing magnetic pole S1 on the surface of the developing sleeve 30 is 5 × 10^-2(T)-2 x 10^-1(T) is preferred. The magnet roller 31 has N1, N2, N3, and S2 poles in addition to the developing magnetic pole S1.
[0192]
Here, the developing process of visualizing the electrostatic image on the surface of the electrostatic image carrier 1 by the two-component magnetic brush method using the developing device 32 and the circulation system of the developer T will be described.
[0193]
The developer T pumped up at the N2 pole by the rotation of the developing sleeve 30 is transported from the S2 pole to the N1 pole, and the thickness of the developer layer on the sleeve is regulated by the regulating blade 33 on the way, and the developer thin layer is removed. Form. Then, the developer T raised in the magnetic field of the developing magnetic pole S1 develops the electrostatic image on the electrostatic image carrier 1. Thereafter, the developer T on the developing sleeve 30 falls into the developing chamber R1 due to the repulsive magnetic field between the N3 pole and the N2 pole. The developer T that has dropped into the developing chamber R1 is agitated and transported by the transport screw 37.
[0194]
Next, an image forming operation of the above-described image forming apparatus will be described with reference to FIG.
[0195]
The electrostatic image carrier 1 is driven to rotate around a central support shaft at a predetermined peripheral speed (process speed) in the direction of arrow a (counterclockwise), and in the rotation process, the primary charger 2 according to the present embodiment. In this case, a uniform negative polarity charging process is performed.
[0196]
Then, the scanning exposure L by the laser light modulated corresponding to the image signal output from the image reading unit B to the printer unit A is performed on the uniformly charged surface of the electrostatic image carrier 1 by an exposure device (laser). The scanning device 3 outputs an electrostatic image of each color corresponding to the image information of the original G that is photoelectrically read by the image reading unit B on the electrostatic image carrier 1. The electrostatic image formed on the electrostatic image carrier 1 is visualized by the developing device 4 by the above-described two-component magnetic brush method. First, the image is reversely developed by a developing device containing the first color toner, and is visualized as a first color toner image.
[0197]
On the other hand, in synchronization with the formation of the toner image on the electrostatic image carrier 1, the transfer material P such as paper stored in the paper feed cassette 10 is fed one by one by the paper feed roller 11 or 12. Then, the sheet is fed to the transfer body 5 at a predetermined timing by the registration roller 13, and the transfer material P is electrostatically attracted onto the transfer body 5 by the suction roller 14. The transfer material P electrostatically attracted onto the transfer member 5 moves to a position facing the electrostatic image carrier 1 by rotating the transfer member 5 in the direction of the arrow (clockwise), and the transfer material P is transferred by the transfer charger 5a. Is charged on the back side of the toner, and the toner image on the electrostatic image carrier 1 is transferred to the front side.
[0198]
The transfer member 5 has a transfer sheet 5c made of, for example, a polyethylene terephthalate resin film stretched on the surface thereof, and is provided so as to be able to abut and separate from the electrostatic image carrier 1. The transfer body 5 is driven to rotate in the direction of the arrow (clockwise). In the transfer member 5, a transfer charger 5a, a separation charger 5b, and the like are provided.
[0199]
After this transfer, the transfer residual toner remaining on the electrostatic image carrier 1 is removed by the cleaning device 6, and the electrostatic image carrier 1 is used for forming the next toner image.
[0200]
Thereafter, similarly, the electrostatic image on the electrostatic image carrier 1 is developed, and each color toner image formed on the electrostatic image carrier 1 is transferred onto the transfer material P on the transfer body 5 by the transfer charger 5a. The images are superimposed and transferred to form a full-color image.
[0201]
Then, the transfer material P is separated from the transfer body 5 by the separation charger 5b, and the separated transfer material P is transported to the fixing device 9 through the transport belt 8. The transfer material P conveyed to the fixing device 9 is heated and pressed between the fixing roller 9a and the pressure roller 9b to fix a full-color image on the surface, and then discharged onto the tray 16 by the discharge roller 15. Paper.
[0202]
Further, the transfer residual toner is removed from the surface of the electrostatic image carrier 1 by the cleaning device 6, and the surface of the electrostatic image carrier 1 is discharged by the pre-exposure lamp 7 and used for the next image formation.
[0203]
The present invention is also applicable to a tandem-type full-color image forming apparatus as shown in FIG.
[0204]
The configuration of the tandem type image forming apparatus shown in FIG. 16 will be briefly described. This image forming apparatus includes five image forming units, each of which has a photosensitive drum (electrostatic image carrier) 1a, 1b, 1c, 1d, 1e and a primary charger 2a, 2b. , 2c, 2d, and 2e, and developing devices 4a, 4b, 4c, 4d, and 4e. The developing devices 4a, 4b, 4c, 4d, and 4e store magenta, dark cyan, light cyan, yellow, and black toners, respectively. FIG. 16 shows a mode using the dark cyan toner and the light cyan toner. However, a dark magenta toner and a light magenta toner may be used instead, or a developing device is further added, and both are used in combination. Is also good.
[0205]
At the time of image formation, first, each photosensitive drum is charged by each primary charger, and a laser beam modulated according to an image signal output from the image reading unit B to the printer unit A side is exposed to an exposure device (laser scanning device). 3), the respective photosensitive drums are scanned and exposed by the laser light, and thereby magenta, dark cyan, light cyan, yellow, and black corresponding to the image information of the original G photoelectrically read by the image reading unit 21. An electrostatic charge image corresponding to each color is formed on each photosensitive drum.
[0206]
The electrostatic image formed on each photosensitive drum is developed by magenta, dark cyan, light cyan, yellow, and black toners by each developing device, and is visualized as a toner image.
[0207]
Then, in synchronization with the formation of each color toner image on each photosensitive drum, each color (magenta, dark cyan, light cyan) of each photosensitive drum is transferred onto a transfer material P such as paper electrostatically attracted onto the transfer belt 5 and conveyed. , Yellow, and black) toner images are successively multiplex-transferred to form a full-color image.
[0208]
The transfer material on which the full-color image is formed is heated and pressed by the fixing device 9 to be fixed, and then discharged outside.
[0209]
【Example】
Hereinafter, the present invention will be described specifically with reference to Production Examples and Examples, but these do not limit the present invention at all.
[0210]

The above raw materials are premixed by a Henschel mixer, melt-kneaded by a twin-screw extruder, cooled, coarsely ground to about 1 to 2 mm using a hammer mill, and then finely ground by an air jet-type fine mill. did. The obtained finely pulverized product was classified to obtain cyan toner particles having a weight average particle diameter of 6.4 μm.
[0211]
To 100 parts by mass of the obtained cyan toner particles, dry silica having a primary particle diameter of 12 nm (BET specific surface area of 120 m) treated with silicone oil and hexamethyldisilazane.²/ G) External addition of 2.5 parts by mass gave Cyan Toner 1. Tables 1 and 2 show the physical properties of Cyan Toner 1.
[0212]
(Production Examples 2 to 5 of cyan toner)
Cyan toners 2 to 5 were obtained in the same manner as in Production Example 1 of the toner except that the amounts of the colorant, the charge control agent, and the external additive were set to the values shown in Table 1. Physical properties are shown in Tables 1 and 2.
[0213]
(Production Example 6 of Cyan Toner)
In a 2 liter four-necked flask equipped with a high-speed stirrer TK-homomixer, 350 parts by mass of ion-exchanged water and 0.1 mol / l-Na₃PO₄225 parts by mass of the aqueous solution was added, the rotation speed of the homomixer was adjusted to 12000 rpm, and the mixture was heated to 65 ° C. Here, 1.0 mol / liter-CaCl₂34 parts by mass of an aqueous solution is gradually added, and a fine poorly water-soluble dispersant Ca is added.₃(PO₄)₂The aqueous dispersion medium containing was prepared.

The above material was dispersed for 3 hours using an attritor to form a polymerizable monomer composition, and then 4 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was added. The water-soluble monomer composition was charged into the aqueous dispersion medium, and granulated for 15 minutes while maintaining the rotation speed at 12,000 rpm. Thereafter, the high-speed stirring device was changed to a normal propeller stirring device, the internal temperature was raised to 80 ° C., and polymerization was carried out for 10 hours while maintaining the rotation speed of the stirring device at 150 rpm. After completion of the polymerization, the mixture was cooled, and dilute hydrochloric acid was added to the aqueous dispersion medium to dissolve the poorly water-soluble dispersant. Further, washing and drying were performed to obtain cyan toner particles having a weight average particle diameter of 5.5 μm.
[0214]
To 100 parts by mass of the obtained cyan toner particles, dry silica having a primary particle diameter of 12 nm (BET specific surface area of 120 m) treated with silicone oil and hexamethyldisilazane.²/ G) Cyan toner 6 was obtained by externally adding 2.5 parts by mass. Tables 1 and 2 show physical properties of the cyan toner 6 obtained in the same manner as the cyan toner 1.
[0215]
(Production Examples 7 to 10 of cyan toner)
Cyan toners 7 to 10 were obtained in the same manner as in the production example 6 of the cyan toner, except that the addition amounts of the coloring agent, the charge control agent, and the external additive were set to the numerical values shown in Table 1. Tables 1 and 2 show the physical properties of the cyan toners 7 to 10 determined in the same manner as the cyan toner 1.
[0216]
[Table 1]

[0219]
[Table 2]

[0218]
(Example A-1)
Cyan toner 1 and a ferrite carrier (average particle size: 42 μm) surface-coated with a silicone resin were mixed so that the toner concentration became 6% by mass, to prepare two-component developer 1 (for dark colors). Similarly, a two-component developer 3 (for light color) was prepared by mixing a cyan toner 3 and a ferrite carrier (average particle size 42 μm) surface-coated with a silicone resin so that the toner concentration became 6% by mass. .
[0219]
Cyan toner kit 1 was obtained by combining two-component developer 1 and two-component developer 3.
[0220]
A two-component developer 1 was set in a cyan developing device and a two-component developer 3 was set in a magenta developing device of a commercially available plain paper full-color copying machine (color laser copying machine CLC1150; manufactured by Canon Inc.). Using plain paper (color laser copier paper TKCLA4; manufactured by Canon Inc.), a patch image was formed by overlapping images of 12 gradations of the light-color cyan toner and 12 gradations of the dark-color cyan toner by crossing each other at 90 degrees in the printer mode. FIG. 9 shows an example of image data and an output image in the printer mode.
[0221]
FIG. 7 shows an image formed by the two-component developer 1, and FIG. 8 shows an image formed by the two-component developer 3. By forming such images of FIGS. 7 and 8 on one sheet of paper, the image of FIG. 9 is formed.
[0222]
Using SpectroScan @ Transmission (manufactured by GretagMacbeth), the L of each patch is used.^*, A^*, B^*Measure the value and^*, B^*Value to c^*I asked. c^*The horizontal axis represents the value, L^*The value is plotted on the vertical axis and the value of each patch is plotted c^*-L^*The figure was created. L^*= 60 straight line and c^*The area of a region surrounded by a straight line of = 0 and each measured value was determined, and the size of a reproducible color space was compared. L^*If the value does not reach 60, the minimum L^*Through the point indicating the value c^*A straight line drawn parallel to the axis and L^*The area of the region surrounded by the straight line of = 0 and each measurement value was determined. Table 3 shows the evaluation results.
[0223]
Also, L^*Patch images of a low-density region having a value of 85 or more and less than 100 and a patch image of a medium-density region having a value of 70 or more and less than 85 were extracted, and the graininess of these images was visually evaluated according to the following evaluation criteria. Table 3 shows the evaluation results.
A: Very good granularity and roughness.
B: Good granularity and roughness.
C: There is normal graininess and roughness.
D: Graininess or roughness is slightly conspicuous, but within a practical range.
E: Granularity and roughness are conspicuous.
[0224]
(Examples A-2 to A-5, Comparative Examples A-1 to A-5)
The configuration of the toner kit was as shown in Table 3. Otherwise, the image was evaluated in the same manner as in Example A-1. Table 3 shows the results.
[0225]
[Table 3]

[0226]
(Example A-6)
The two-component developer 2 and the two-component developer 3 were combined to obtain a cyan toner kit.
[0227]
A two-component developer 2 was set in a cyan developing device and a two-component developer 3 was set in a magenta developing device of a commercially available plain paper full-color copying machine (color laser copying machine CLC1150; manufactured by Canon Inc.). Using plain paper (color laser copier paper TKCLA4; manufactured by Canon), the image output based on FIG. 15 was visually evaluated for graininess and roughness according to the following evaluation criteria in the same manner as in Example A-1. Table 4 shows the evaluation results.
A: Very good granularity and roughness.
B: Good granularity and roughness.
C: There is normal graininess and roughness.
D: Graininess or roughness is slightly conspicuous, but within a practical range.
E: Granularity and roughness are conspicuous.
[0228]
Further, the gradation was visually evaluated according to the following evaluation criteria. Table 4 shows the evaluation results.
A: The gradation is very good.
B: Good gradation.
C: Normal gradation.
D: The gradation property is insufficient or the gradation property is uncomfortable.
[0229]
Further, in the same manner as in Example A-1, c^*-L^*Create a diagram, L^*= 60 straight line and c^*The area of a region surrounded by a straight line of = 0 and each measured value was determined, and the size of a reproducible color space was compared. L^*If the value does not reach 60, the minimum L^*Through the point indicating the value c^*A straight line drawn parallel to the axis and L^*The area of the region surrounded by the straight line of = 0 and each measurement value was determined. Table 4 shows the evaluation results.
[0230]
(Comparative Examples A-6 and A-7)
An image was evaluated in the same manner as in Example A-6, except that the two-component developer shown in Table 4 was set in a cyan developing device, the magenta developing device was not used, and the output was based on FIG. Table 4 shows the results.
[0231]
(Examples A-7 and A-8, Comparative Examples A-8 and A-9)
The configuration of the toner kit was as shown in Table 4. Otherwise, the results of image evaluation performed in the same manner as in Example A-6 are shown in Table 4.
[0232]
[Table 4]

[0233]
(Production example of black toner, yellow toner and magenta toner)
A black toner, a yellow toner, and a magenta toner were obtained in the same manner as in Production Example 1 of the cyan toner except that the amounts of the colorant, the charge control agent, and the external additive were changed to the values shown in Table 7. Table 5 shows the physical properties. Each of these toners and a ferrite carrier (average particle size: 42 μm) surface-coated with a silicone resin are mixed so that the toner concentration becomes 6% by mass, and a black developer, a yellow developer, and a magenta developer are mixed. Got.
[0234]
[Table 5]

[0235]
(Example A-9)
The toner kit was configured as follows, and an image was formed using the electrophotographic apparatus shown in FIG. The significant difference in each combination was examined.
(A):
In the developing device 411a, a dark cyan developer (cyan developer 1 used in Comparative Example A-6)
The above-mentioned magenta developer is supplied to the developing device 412.
The above-mentioned yellow developer is supplied to the developing device 413.
The above-mentioned black developer is supplied to the developing device 414.
(B):
In the developing device 411a, a dark cyan developer (cyan developer 2 used in Example A-6)
Light cyan developer (cyan developer 3 used in Example A-6) in developing device 411b
The above-mentioned magenta developer is supplied to the developing device 412.
The above-mentioned yellow developer is supplied to the developing device 413.
The above-mentioned black developer is supplied to the developing device 414.
(C):
Light-colored cyan developer (cyan developer 3 used in Comparative Example A-7) in developing device 411b
The above-mentioned magenta developer is supplied to the developing device 412.
The above-mentioned yellow developer is supplied to the developing device 413.
The above-mentioned black developer is supplied to the developing device 414.
(D):
In the developing device 411a, a dark cyan developer (the cyan developer 10 used in Comparative Example A-9)
Light-colored cyan developer (cyan developer 5 used in Comparative Example A-9) in developing device 411b
The above-mentioned magenta developer is supplied to the developing device 412.
The above-mentioned yellow developer is supplied to the developing device 413.
The above-mentioned black developer is supplied to the developing device 414.
As a result, as compared with (a), (b) suppresses graininess and roughness over the entire range from the low-density part to the high-density part in the green to purple secondary colors, and the color reproduction range is low. A wide good image was obtained.
[0236]
On the other hand, in (c), although the graininess was reduced in the low density portion, the expressible hue range was reduced. In (d), although the graininess of the low density portion in the secondary color was reduced compared to (a), the image was inferior in the graininess of the middle density portion. Further, the expressible color space did not increase, and was smaller than that of FIG. That is, as shown in (b), by using a dark cyan toner and a light cyan toner having a hue range defined by the present invention, the effect of the present invention can be obtained in a full-color electrophotographic apparatus as in the present embodiment. It was fully demonstrated.
[0237]
(Example A-10)
A toner kit was configured with the following combinations, and evaluated using a commercially available full-color one-component image forming apparatus (Creative Processor 660; manufactured by Canon Inc.) in the same manner as in Example A-6.
(A):
Dark cyan toner (using cyan toner 7 as dark cyan one-component developer) in cyan developing device
(B):
Light cyan toner in cyan developing device (use cyan toner 8 as light cyan one-component developer)
(C):
Dark cyan toner (using cyan toner 7 as dark cyan one-component developer) in cyan developing device
Light-colored cyan toner in magenta developing device (using cyan toner 8 as light-colored cyan one-component developer)
(D):
Cyan toner in cyan developing device (Cyan toner 10 is used as a one-component developer of dark cyan)
Cyan toner in magenta developing unit (Cyan toner 9 is used as a light-color cyan one-component developer)
As a result, in the case of (c), the granularity and the roughness are suppressed most, and a good image having a wide color reproduction range can be obtained. Was confirmed.
[0238]

The above raw materials are premixed by a Henschel mixer, melt-kneaded by a twin-screw extruder, cooled, coarsely ground to about 1 to 2 mm using a hammer mill, and then finely ground by an air jet-type fine mill. did. The obtained finely pulverized product was classified to obtain magenta toner particles having a weight average particle size of 6.1 μm.
[0239]
100 parts by mass of the obtained magenta toner particles were dried silica having a primary particle diameter of 12 nm (BET specific surface area of 120 m) treated with silicone oil and hexamethyldisilazane.²/ G) 2.4 parts by mass were externally added to obtain a dark magenta toner 1. Tables 6 and 7 show the physical properties of the dark magenta toner 1.
[0240]
(Production Examples 2 to 6 of magenta toner)
The dark magenta toner 2 and the light magenta toner 1 were manufactured in the same manner as in Production Example 1 of the toner except that the types and amounts of the colorant and the amounts of the charge control agent and the external additive were set to the numerical values shown in Table 8, respectively. ~ 4. Tables 6 and 7 show the physical properties of the dark magenta toner 2 and the light magenta toners 1 to 4.
[0241]
(Production Example 7 of Magenta Toner)
In a 2 liter four-necked flask equipped with a high-speed stirrer TK-homomixer, 350 parts by mass of ion-exchanged water and 0.1 mol / l-Na₃PO₄225 parts by mass of the aqueous solution was added, the rotation speed of the homomixer was adjusted to 12000 rpm, and the mixture was heated to 65 ° C. Here, 1.0 mol / liter-CaCl₂34 parts by mass of an aqueous solution is gradually added, and a fine poorly water-soluble dispersant Ca is added.₃(PO₄)₂The aqueous dispersion medium containing was prepared.

The above material was dispersed for 3 hours using an attritor to form a polymerizable monomer composition, and then 4 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was added. The water-soluble monomer composition was charged into the aqueous dispersion medium, and granulated for 15 minutes while maintaining the rotation speed at 12,000 rpm. Thereafter, the high-speed stirring device was changed to a normal propeller stirring device, the internal temperature was raised to 80 ° C., and polymerization was carried out for 10 hours while maintaining the rotation speed of the stirring device at 150 rpm. After completion of the polymerization, the mixture was cooled, and dilute hydrochloric acid was added to the aqueous dispersion medium to dissolve the poorly water-soluble dispersant. After further washing and drying, magenta toner particles having a weight average particle diameter of 5.3 μm were obtained.
[0242]
100 parts by mass of the obtained magenta toner particles were coated with dry silica having a primary particle diameter of 12 nm (BET specific surface area of 120 m) treated with silicone oil and hexamethyldisilazane.²/ G) By adding 2.2 parts by mass, a dark magenta toner 3 was obtained. Tables 6 and 7 show the physical properties of the dark magenta toner 3 obtained in the same manner as the dark magenta toner 1.
[0243]
(Production Examples 8 to 11 of magenta toner)
Dark magenta toner 4 and light magenta toners 5 to 7 were obtained in the same manner as in Production Example 7 of the magenta toner, except that the amounts of the colorant, the charge control agent, and the external additives were set to the values shown in Table 6. Tables 6 and 7 show the physical properties of the dark magenta toner 4 and the light magenta toners 5 to 7 obtained in the same manner as the dark magenta toner 1.
[0244]
[Table 6]

[0245]
[Table 7]

[0246]
(Example B-1)
The light-color magenta toner 1 and a ferrite carrier (average particle size: 42 μm) surface-coated with a silicone resin were mixed so that the toner concentration became 6% by mass, to prepare a light-color magenta two-component developer. Dark magenta toner 1 and a ferrite carrier (average particle size 42 μm) surface-coated with a silicone resin were mixed so that the toner concentration became 6% by mass, to prepare a dark magenta two-component developer.
[0247]
A magenta toner kit 1 was obtained by combining a light-colored magenta two-component developer and a dark-colored magenta two-component developer.
[0248]
A two-component developer having dark magenta toner 1 is set in a cyan developing device of a commercially available plain paper full-color copying machine (color laser copying machine CLC1150; manufactured by Canon), and a two-component developer having light magenta toner 1 is set in a magenta developing device. The dark magenta toner 1 was introduced into the cyan toner hopper, and the light magenta toner 1 was introduced into the magenta toner hopper. Using plain paper (color laser copier paper TKCLA4; manufactured by Canon), a patch image was formed by superimposing images of 12 gradations of light magenta toner and 12 gradations of dark magenta toner at 90 degrees in printer mode. FIG. 9 shows an example of image data and an output image in the printer mode.
[0249]
Using SpectroScan @ Transmission (manufactured by GretagMacbeth), the L of each patch is used.^*, A^*, B^*Measure the value and^*, B^*Value to c^*I asked. c^*The horizontal axis represents the value, L^*The value is plotted on the vertical axis and the value of each patch is plotted c^*-L^*The figure was created. L^*= 60 straight line and c^*The area of a region surrounded by a straight line of = 0 and each measured value was determined, and the size of a reproducible color space was compared. L^*If the value does not reach 60, the minimum L^*Through the point indicating the value c^*A straight line drawn parallel to the axis and L^*The area of the region surrounded by the straight line of = 0 and each measurement value was determined. Table 8 shows the evaluation results.
[0250]
Also, L^*Patch images of a low-density region having a value of 85 or more and less than 100 and a patch image of a medium-density region having a value of 70 or more and less than 85 were extracted, and the graininess of these images was visually evaluated according to the following evaluation criteria. Table 8 shows the evaluation results.
A: Very good granularity and roughness.
B: Good granularity and roughness.
C: There is normal graininess and roughness.
D: Graininess or roughness is slightly conspicuous, but within a practical range.
E: Granularity or roughness is conspicuous.
[0251]
(Examples B-2 to B-7, Comparative Examples B-1 to B-5)
The composition of the toner kit was as shown in Table 8. Otherwise, the image was evaluated in the same manner as in Example B-1. Table 8 shows the results.
[0252]
Further, in Example B-4, for the magenta toner kit 4 in which a good result was obtained in the above evaluation, the same patch image as that of Example B-1 was output continuously for 6000 sheets, and then the magenta toner kit 4 was used. Each toner was supplied to each hopper, and a continuous image output of 6000 sheets was similarly repeated five times. It was confirmed that the effect of reducing the graininess and the effect of extending the color reproduction range were maintained by continuous output, and that a good image was obtained.
[0253]
[Table 8]

[0254]
(Example B-8)
The light-color magenta toner 2 and a ferrite carrier (average particle size: 42 μm) surface-coated with a silicone resin were mixed so that the toner concentration became 6% by mass to prepare a light-color magenta two-component developer. Further, a dark magenta two-component developer was prepared in the same manner except that dark magenta toner 2 was used.
[0255]
A magenta toner kit 13 was obtained by combining a light-colored magenta two-component developer and a dark-colored magenta two-component developer.
[0256]
A commercially available plain paper full-color copier (color laser copier CLC1150; manufactured by Canon) is set with a dark magenta two-component developer in a cyan developer and a light magenta two-component developer in a magenta developer. The light magenta toner 2 was introduced into the dark magenta toner 2 and the magenta toner hopper, respectively. Using plain paper (color laser copier paper TKCLA4; manufactured by Canon), the image output based on FIG. 15 was visually evaluated for graininess and roughness according to the following evaluation criteria in the same manner as in Example B-1. Table 9 shows the evaluation results.
A: Very good granularity and roughness.
B: Good granularity and roughness.
C: There is normal graininess and roughness.
D: Graininess or roughness is slightly conspicuous, but within a practical range.
[0257]
E: Granularity or roughness is conspicuous.
[0258]
Further, the gradation was visually evaluated according to the following evaluation criteria. Table 9 shows the evaluation results.
A: The gradation is very good.
B: Good gradation.
C: Normal gradation.
D: The gradation property is insufficient or the gradation property is uncomfortable.
[0259]
Further, in the same manner as in Example B-1, c^*-L^*Create a diagram, L^*= 60 straight line and c^*The area of a region surrounded by a straight line of = 0 and each measured value was determined, and the size of a reproducible color space was compared. L^*If the value does not reach 60, the minimum L^*Through the point indicating the value c^*A straight line drawn parallel to the axis and L^*The area of the region surrounded by the straight line of = 0 and each measurement value was determined. Table 9 shows the evaluation results.
[0260]
(Comparative Examples B-6 and B-7)
A dark magenta two-component developer or a light magenta two-component developer was set in a magenta developing device, and toner was introduced into a magenta toner hopper. In this example, no cyan developing device was used. The image was evaluated in the same manner as in Example B-8 except that the image was output based on FIG. Table 9 shows the results.
[0261]
(Examples B-9 to B-12, Comparative Examples B-8, B-9)
The configuration of the toner kit was as shown in Table 9. Otherwise, the image was evaluated in the same manner as in Example B-8. Table 9 shows the results.
[0262]
[Table 9]

[0263]
(Production example of black toner, yellow toner, cyan toner)
A black toner, a yellow toner, and a cyan toner were obtained in the same manner as in Production Example 7 of the magenta toner, except that the addition amounts of the colorant, the charge control agent, and the external additive were set to the values shown in Table 10. Table 10 shows the physical properties.
[0264]
[Table 10]

[0265]
(Example B-13)
Using the toners described below, a two-component developer was prepared in the same manner as in Example B-8. The toner kit was configured to include the prepared four or five types of two-component developers. Images were formed using the electrophotographic apparatus shown in FIG. 10, and significant differences were examined.
(A):
Dark magenta toner 1
The above cyan toner
The above yellow toner
Above black toner
(B):
Dark magenta toner 3
Light color magenta toner 5
The above cyan toner
The above yellow toner
Above black toner
(C):
Light color magenta toner 3
The above cyan toner
The above yellow toner
Above black toner
(D):
Dark magenta toner 1
Light color magenta toner 3
The above cyan toner
The above yellow toner
Above black toner
As a result, compared to (a), (b) suppresses graininess and roughness in the entire range from the low density portion to the high density portion in the orange to purple secondary colors, and has a wide color reproduction range. Good images were obtained.
[0266]
On the other hand, in (c), although the graininess was reduced in the low density portion, the expressible hue range was reduced. (D) was an image in which the granularity of the low density was reduced in the secondary color as compared with (a), but the granularity of the medium density portion was increased. Further, the expressible color space did not increase, and was smaller than that of FIG. That is, as shown in (b), by using a dark magenta toner and a light magenta toner having a hue range defined by the present invention, the effect of the present invention can be achieved in a full-color electrophotographic apparatus as in the present embodiment. Was fully demonstrated.
[0267]
(Example B-14)
A toner kit was composed of the following combinations, and evaluated using a commercially available full-color one-component image forming apparatus (Creative Processor 660; manufactured by Canon Inc.) in the same manner as in Example B-8.
(A):
Dark magenta toner in cyan developing device (using dark magenta toner 3 as one-component developer)
(B):
Light-colored magenta toner in cyan developing unit (light-colored magenta toner 5 is used as one-component developer)
(C):
Dark magenta toner in cyan developing device (using dark magenta toner 3 as one-component developer)
Light magenta toner in magenta developing unit (light magenta toner 5 is used as one-component developer)
(D):
Dark magenta toner in cyan developing device (using dark magenta toner 3 as one-component developer)
Light color magenta toner in magenta developing unit (light color magenta toner 7 is used as one-component developer)
As a result, in the case of (c), the granularity and roughness are suppressed most, a good image having a wide color reproduction range is obtained, and the effect of the present invention is sufficiently exhibited even in a one-component developing apparatus. Was confirmed.
[0268]
(Example C-1)
In a 2 liter four-necked flask equipped with a high-speed stirrer TK-homomixer, 350 parts by mass of ion-exchanged water and 0.1 mol / l-Na₃PO₄225 parts by mass of the aqueous solution was added, the rotation speed of the homomixer was adjusted to 12000 rpm, and the mixture was heated to 65 ° C. Here, 1.0 mol / liter-CaCl₂34 parts by mass of an aqueous solution is gradually added, and a fine poorly water-soluble dispersant Ca is added.₃(PO₄)₂The aqueous dispersion medium containing was prepared.

The above material was dispersed for 3 hours using an attritor to form a polymerizable monomer composition, and then 4 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was added. The water-soluble monomer composition was charged into the aqueous dispersion medium, and granulated for 15 minutes while maintaining the rotation speed at 12,000 rpm. Thereafter, the high-speed stirring device was changed to a normal propeller stirring device, the internal temperature was raised to 80 ° C., and polymerization was carried out for 10 hours while maintaining the rotation speed of the stirring device at 150 rpm. After completion of the polymerization, the mixture was cooled, and dilute hydrochloric acid was added to the aqueous dispersion medium to dissolve the poorly water-soluble dispersant. Further, washing and drying were performed to obtain light-colored cyan toner particles having a weight average particle diameter of 6.3 μm.
[0269]
100 parts by mass of the obtained light-colored cyan toner particles were coated with dry silica having a primary particle diameter of 12 nm (BET specific surface area of 120 m) treated with silicone oil and hexmethyldisilazane.²/ G) By adding 1.4 parts by mass, a light cyan toner 1 was obtained.
[0270]
A light-colored magenta toner 1 was obtained in the same manner as in the method of producing the light-colored cyan toner 1 except that the types and amounts of the colorants and the amounts of the charge control agent and the external additives were changed as shown in Table 11. Was.
[0271]
In a 2 liter four-necked flask equipped with a high-speed stirrer TK-homomixer, 350 parts by mass of ion-exchanged water and 0.1 mol / l-Na₃PO₄225 parts by mass of the aqueous solution was added, the rotation speed of the homomixer was adjusted to 12,000 rpm, and the mixture was heated to 65 ° C. Here, 1.0 mol / liter-CaCl₂34 parts by mass of an aqueous solution is gradually added, and a fine poorly water-soluble dispersant Ca is added.₃(PO₄)₂The aqueous dispersion medium containing was prepared.

The above material was dispersed for 3 hours using an attritor to form a polymerizable monomer composition, and then 4 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was added. The water-soluble monomer composition was charged into the aqueous dispersion medium, and granulated for 15 minutes while maintaining the rotation speed at 12,000 rpm. Thereafter, the high-speed stirring device was changed to a normal propeller stirring device, the internal temperature was raised to 80 ° C., and polymerization was carried out for 10 hours while maintaining the rotation speed of the stirring device at 150 rpm. After completion of the polymerization, the mixture was cooled, and dilute hydrochloric acid was added to the aqueous dispersion medium to dissolve the poorly water-soluble dispersant. Further, washing and drying were performed to obtain dark cyan toner particles having a weight average particle size of 5.4 μm.
[0272]
100 parts by mass of the obtained dark cyan toner particles were dried silica having a primary particle diameter of 12 nm (BET specific surface area of 120 m) treated with silicone oil and hexamethyldisilazane.²/ G) 2.5 parts by mass were externally added to obtain a dark cyan toner 1.
[0273]
Except that the type and amount of the colorant and the amounts of the charge control agent and the external additive were changed as shown in Table 11, the dark magenta toner 1 , Yellow toner 1 and black toner 1. Tables 11 and 13 show the physical properties of each toner. Each toner was mixed with a ferrite carrier (average particle size: 42 μm) surface-coated with a silicone resin so that the toner concentration became 6% by mass, to prepare a two-component developer.
[0274]
The light cyan two-component developer containing the light cyan toner 1 thus obtained, the light magenta two-component developer containing the light magenta toner 1, the dark cyan two-component developer containing the dark cyan toner 1, and the dark color Toner kit 1 was obtained by combining a dark magenta two-component developer containing magenta toner 1, a yellow two-component developer containing yellow toner 1, and a black two-component developer containing black toner 1.
[0275]
Using the electrophotographic apparatus shown in FIG. 10, image formation evaluation was performed with the toner configuration of the toner kit 1. The description of the electrophotographic apparatus is as described above. In this embodiment, a light-color cyan two-component developer is used in the developing device 411a, a light-color magenta two-component developer is used in the developing device 411b, a yellow two-component developer is used in the developing device 412, a dark-color cyan two-component developer is used in the developing device 413. A dark magenta two-component developer was set in a developing device 414, and a black two-component developer was set in a developing device 415. When the two-component developer is set in each developing device, the light-color cyan toner 1 is applied to the toner hopper of the developing device 411a, the light-color magenta toner 1 is applied to the toner hopper of the developing device 411b, and the yellow toner 1 is applied to the toner hopper of the developing device 412. The dark cyan toner 1 was introduced into the toner hopper of the developing device 413, the dark magenta toner 1 was introduced into the toner hopper of the developing device 414, and the black toner 1 was introduced into the toner hopper of the developing device 415.
[0276]
Using a light cyan toner and a dark cyan toner, a 12-gradation cyan image is formed based on FIG. 15, and a 12-gradation magenta image is formed using the light magenta toner and the dark magenta toner based on FIG. Was formed. In addition, using a yellow toner and a black toner, a 12-gradation yellow image and a black image were formed based on FIG. Using plain paper (color laser copier paper TKCLA4; manufactured by Canon), a patch image was formed in the printer mode in which a cyan image and a magenta image, a cyan image and a yellow image, and a magenta image and a yellow image were respectively superimposed at 90 degrees and crossed. FIG. 9 shows an example of the output image.
[0277]
Using SpectroScan @ Transmission (manufactured by GretagMacbeth), the output image L^*, A^*, B^*The value was measured. a^*, B^*Value to c^*And c^*The horizontal axis represents the value, L^*C plotted for each color, with values on the vertical axis^*-L^*The figure was created. c^*The patch images in the low-density region where the value was 1 or more and less than 20 and the patch images in the middle-density region where the value was 20 or more and less than 40 were extracted, and the graininess of these images was visually evaluated according to the following evaluation criteria.
A: Very good granularity and roughness.
B: Good granularity and roughness.
C: There is normal graininess and roughness.
D: Graininess or roughness is slightly conspicuous, but within a practical range.
E: Granularity or roughness is conspicuous.
[0278]
Table 14 shows the evaluation results. According to the present example, a good image with a wide color reproduction range was obtained with suppressed graininess and roughness over the entire color gamut from the low density portion to the high density portion.
[0279]
Further, a 12-tone patch image of cyan, magenta, red, green, and blue is output, and c^*-L^*The figure was created. L^*= 60 straight line and c^*The area of a region surrounded by a straight line of = 0 and each measured value was determined, and the size of a reproducible color space was compared. L^*If the value does not reach 60, the minimum L^*Through the point indicating the value c^*A straight line drawn parallel to the axis and L^*The area of the region surrounded by the straight line of = 0 and each measurement value was determined. Table 14 shows the evaluation results.
[0280]
Further, 6,000 sheets of images each having a printing rate of each toner of 10% were continuously output. Further, while replenishing each toner, the continuous image output of 6000 sheets was similarly repeated five times. It was confirmed that the effect of reducing the graininess and the effect of extending the color reproduction range were maintained by continuous output, and that a good image was obtained.
[0281]
(Example C-2)
Except that the type and amount of the colorant and the amounts of the charge control agent and the external additive were changed as shown in Table 11, the light cyan toner 2 and the light cyan toner 2 were prepared in the same manner as in the method of producing the dark cyan toner 1 described above. A dark magenta toner 2 was obtained. Tables 11 and 13 show the physical properties of each toner.
[0282]
Using the obtained toner, in the same manner as in Example C-1, a light cyan two-component developer containing the light cyan toner 2, a light magenta two-component developer containing the light magenta toner 1, and a dark cyan toner 2, a dark magenta two-component developer containing a dark magenta toner 2, a yellow two-component developer containing a yellow toner 1, and a black two-component developer containing a black toner 1. An agent was prepared. These combinations were designated as toner kit 2.
[0283]
When the image formation evaluation was performed using the toner configuration of the toner kit 2, the color reproduction range was slightly narrower than that of Example C-1, but the granularity was reduced over the entire color gamut from the low density portion to the high density portion. A good image in which roughness was suppressed was obtained. Table 14 shows the evaluation results.
[0284]
(Comparative Example C-1)
In the toner kit 1 of Example C-1, a toner kit 3 having four kinds of developers excluding the light-color cyan two-component developer and the light-color magenta two-component developer was formed. Tables 11 and 13 show the physical properties of each toner included in the toner kit 3. The image was evaluated in the same manner as in Example C-1, except that the image of each color was output for each color toner based on FIG. 17 to obtain a patch image without using the developing devices 411a and 411b. As a result, the color reproduction range was smaller than that of Example C-1, and granularity and roughness were observed in the low density portion. Table 14 shows the evaluation results.
[0285]
(Comparative Example C-2)
In the toner kit 1 of the first embodiment, a toner kit 4 having four kinds of developers except for a deep cyan two-component developer and a deep magenta two-component developer was formed. Tables 12 and 13 show the physical properties of each toner included in the toner kit 4. The image was evaluated in the same manner as in Example C-1, except that the image of each color was output for each color toner based on FIG. 17 to obtain a patch image without using the developing devices 411a and 411b. As a result, the granularity of the low density portion was not observed in the entire color gamut, but the color reproduction range was extremely small. Table 14 shows the evaluation results.
[0286]
(Comparative Example C-3)
Except that the type and amount of the colorant and the amounts of the charge control agent and the external additives were changed as shown in Table 14, the light cyan toner 3 and the light cyan Magenta toner 2 and dark cyan toner 2 were obtained. Tables 14 and 15 show the physical properties of each toner.
[0287]
Using the obtained toner, in the same manner as in Example C-1, a light cyan two-component developer containing the light cyan toner 3, a light magenta two-component developer containing the light magenta toner 2, and a dark cyan toner 2, a dark magenta two-component developer containing dark magenta toner 1, a yellow two-component developer containing yellow toner 1, and a black two-component developer containing black toner 1. An agent was prepared. These combinations were referred to as toner kit 5.
[0288]
Image output evaluation was performed using the toner configuration of the toner kit 5. As a result, the color reproduction range was smaller than that of Example C-1, and the granularity and roughness of the middle density portion were conspicuous. Table 14 shows the evaluation results.
[0289]

The above raw materials are premixed by a Henschel mixer, melt-kneaded by a twin-screw extruder, cooled, coarsely ground to about 1 to 2 mm using a hammer mill, and then finely ground by an air jet-type fine mill. did. The obtained finely pulverized product was classified to obtain pale cyan toner particles having a weight average particle size of 7.3 μm.
[0290]
100 parts by mass of the obtained light-colored cyan toner particles were coated with dry silica having a primary particle diameter of 12 nm (BET specific surface area of 120 m) treated with silicone oil and hexamethyldisilazane.²/ G) By externally adding 2.2 parts by mass, a light cyan toner 4 was obtained. Except that the type and amount of the colorant and the amounts of the charge control agent and the external additive were changed as shown in Table 12, the light-color magenta toner 3 and the dark-colored Color cyan toner 3, dark magenta toner 3, yellow toner 2, and black toner 2 were obtained. Tables 12 and 13 show the physical properties of each toner.
[0291]
Using the obtained toner, in the same manner as in Example C-1, a light cyan two-component developer containing the light cyan toner 4, a light magenta two-component developer containing the light magenta toner 3, and a dark cyan toner 2, a dark magenta two-component developer containing dark magenta toner 3, a yellow two-component developer containing yellow toner 3, and a black two-component developer containing black toner 3. An agent was prepared. These combinations were designated as toner kit 6.
[0292]
When the image formation was evaluated with the toner configuration of the toner kit 6, the color reproduction range was slightly narrower than that of Example C-1, but the granularity was reduced over the entire color gamut from the low density portion to the high density portion. -A good image in which roughness was suppressed was obtained. Table 14 shows the evaluation results.
[0293]
[Table 11]

[0294]
[Table 12]

[0295]
[Table 13]

[0296]
[Table 14]

[0297]
【The invention's effect】
By forming an image by using a combination of a dark color toner and a light color toner having a predetermined hue, it is possible to reduce the granularity and roughness from a low density region to a high density region, thereby providing a higher quality image. Can be formed.
[Brief description of the drawings]
FIG. 1 shows L used in the present invention.^*a^*b^*It is a figure which shows the concept of a color system three-dimensionally.
FIG. 2 is a plan view showing the concept of hue, saturation, and hue angle used in the present invention.
FIG. 3 is a diagram illustrating an example of a hue curve of a cyan toner used in the present invention.
FIG. 4 is a diagram illustrating an example of a saturation and brightness curve of a cyan toner used in the present invention.
FIG. 5 is a diagram illustrating an example of a hue curve of a magenta toner used in the present invention.
FIG. 6 is a diagram illustrating an example of a saturation and brightness curve of magenta toner used in the present invention.
FIG. 7 is a view showing an output image of 12 gradations formed by the two-component developer 1 in the example of the present invention.
FIG. 8 is a view showing an output image of 12 gradations formed by the two-component developer 3 in the embodiment of the present invention.
FIG. 9 is a diagram showing a patch image formed by the output images shown in FIGS. 7 and 8;
FIG. 10 is a longitudinal sectional view illustrating an example of a full-color image forming apparatus used in the present invention.
FIG. 11 is a longitudinal sectional view illustrating an example of a configuration of a two-component developing device.
FIG. 12 is a block diagram illustrating an example of image processing.
FIG. 13 is a diagram illustrating an example of a laser exposure optical system used in the present invention.
14 is a diagram showing a developing device in the full-color image forming apparatus shown in FIG.
FIG. 15 is a graph showing the relationship between the recording rates of light cyan toner and dark cyan toner used in the present invention and gradation data.
FIG. 16 is a longitudinal sectional view showing an example of a tandem type image forming apparatus used in the present invention.
FIG. 17 is a graph showing the relationship between the recording rates of light cyan toner and dark cyan toner and gradation data in image formation in a comparative example.
FIG. 18 is a schematic view of an apparatus for measuring a triboelectric charge amount.

Claims (89)

A toner kit having a state in which a light cyan toner containing at least a binder resin and a colorant and a dark cyan toner containing at least a binder resin and a colorant are separated,
When the hue in the red-green direction is a ^* , the hue in the yellow-blue direction is b ^* , and the lightness is L ^* , the toner fixed image on plain paper is represented by an L ^* a ^* b ^* color system.
The pale cyan toner has a value _{^(a * C1)} is -19 to -30 of ^{a *} when the ^{b *} is -20 in the fixed image of the pale cyan toner, ^{b *} is at a -30 ^{a *} of The value (a ^* _C2 ) is -29 to -45,
The dark cyan toner has an a ^* value (a ^* _C3 ) of -7 to -18 when b ^* in the fixed image of the dark cyan toner is -20, and a when b ^* is -30. A toner kit, wherein the value of ^* (a ^* _C4 ) is -10 to -28. The difference between a ^* _C1 and a ^* _C3 (a ^* _C1− a ^* _C3 ) is −22 to −1, and the difference between a ^* _C2 and a ^* _C4 (a ^* _C2− a ^* _C4 ) is −. The toner kit according to claim 1, wherein the number of the toner kit is from 33 to −1. The difference between a ^* _C1 and a ^* _C3 (a ^* _C1− a ^* _C3 ) is −12 to −3, and the difference between a ^* _C2 and a ^* _C4 (a ^* _C2− a ^* _C4 ) is −. The toner kit according to claim 1, wherein the number is 15 to −3. A ^* _C1 is -26 to -21, a ^* _C2 is -37 to -30, a ^* _C3 is -18 to -11, and a ^* _C4 is -27 to -20. , The difference between a ^* _C1 and a ^* _C3 (a ^* _C1− a ^* _C3 ) is −12 to −3, and the difference between a ^* _C2 and a ^* _C4 (a ^* _C2− a ^* _C4 ) is − The toner kit according to claim 1, wherein the number is 15 to −3. The light cyan toner has an L ^* _C value of 85 to 90 when c ^* represented by the following formula is 30, and the dark cyan toner has an L ^* _C value when c ^* is 30. 5. The toner kit according to claim 1, wherein the number of the toners is from 74 to 84. 6.

The toner kit according to any one of claims 1 to 5, wherein the light cyan toner has a hue angle of 214 to 226 °, and the dark cyan toner has a hue angle of 228 to 260 °. The toner kit according to any one of claims 1 to 6, wherein the light cyan toner and the dark cyan toner each include a pigment in the colorant. The light cyan toner contains 0.4 to 1.5% by mass of a colorant based on the total amount of the toner, and the dark cyan toner contains 2.5 to 8.5% by mass of the colorant based on the total amount of the toner. The toner kit according to any one of claims 1 to 7, further comprising: The dark cyan toner, the optical density of the solid image toner amount on paper is 1 mg / cm ² of 1.5 to 2.5, wherein the light cyan toner, the toner amount on the paper at 1 mg / cm ² 9. The toner kit according to claim 1, wherein an optical density of a certain solid image is 0.82 to 1.35. The light cyan toner and the dark cyan toner each contain a charge control agent, and the ratio of the charge control agent content of the light cyan toner to the charge control agent content of the dark cyan toner is 0.60 to 0. 10. The toner kit according to claim 1, wherein 11. The toner kit according to claim 1, wherein the weight average particle diameter of the light cyan toner and the weight average particle diameter of the dark cyan toner are each 3 to 9 [mu] m. The toner kit according to any one of claims 1 to 11, wherein a ratio of a weight average particle diameter of the light cyan toner to a weight average particle diameter of the dark cyan toner is 1.05 to 1.40. The light-colored cyan toner and the dark-colored cyan toner each have an inorganic fine powder selected from the group consisting of titania, alumina, silica, and double oxides thereof, and have a light color with respect to the specific surface area of the dark-colored cyan toner. 13. The toner kit according to claim 1, wherein the ratio of the specific surface area of the cyan toner is 0.60 to 0.95. 14. A light-colored two-component developer containing at least the light-colored cyan toner and carrier, and a dark-colored two-component developer containing at least the dark cyan toner and the carrier. 4. The toner kit according to 1. 14. The toner kit according to claim 1, comprising a light-colored one-component developer composed of the light-colored cyan toner and a dark-colored one-component developer composed of the dark-colored cyan toner. Containing at least a binder resin and a colorant, red - the hue of green direction and a ^*, yellow - the blue direction of the hue and ^{b *, L * a * b} * color system of the lightness and L ^* when showing the toner fixed image on plain paper, ^{b *} is a value _{^(a * C1)} is -19 to -30 of ^{a *} in the case of -20, ^{a *} value when the ^{b *} is -30 ( a ^* _C2 ) is a dark cyan toner used in combination with a light cyan toner having -29 to -45,
The dark cyan toner contains at least a binder resin and a colorant, and when a toner fixed image on plain paper is represented by an L ^* a ^* b ^* color system, when b ^* is -20, a ^* value _{^(a * C3)} is -7 to -18, ^{b *} is dark, characterized in that ^{a *} value _{^(a * C4)} is -10 to -28 when the -30 Cyan toner. The difference between a ^* _C1 and a ^* _C3 (a ^* _C1− a ^* _C3 ) is −22 to −1, and the difference between a ^* _C2 and a ^* _C4 (a ^* _C2− a ^* _C4 ) is −. 17. The dark cyan toner according to claim 16, wherein the number is from 33 to -1. The difference between a ^* _C1 and a ^* _C3 (a ^* _C1− a ^* _C3 ) is −12 to −3, and the difference between a ^* _C2 and a ^* _C4 (a ^* _C2− a ^* _C4 ) is −. The dark cyan toner according to claim 16, wherein the number is 15 to −3. The a ^* _C1 is -26 to -21, the a ^* _C2 is -37 to -30, the a ^* _C3 is -18 to -11, and the a ^* _C4 is -27 to -20. The difference between a ^* _C1 and a ^* _C3 (a ^* _C1- a ^* _C3 ) is -12 to -3, and the difference between a ^* _C2 and a ^* _C4 (a ^* _C2- a ^* _C4 ) is The dark cyan toner according to claim 16, wherein the toner is -15 to -3. Containing at least a binder resin and a colorant, red - the hue of green direction and a ^*, yellow - the blue direction of the hue and ^{b *, L * a * b} * color system of the lightness and L ^* when showing the toner fixed image on plain paper, ^{b *} is a value _{^(a * C3)} is -7 to -18 of ^{a *} in the case of -20, ^{a *} value when the ^{b *} is -30 ( a ^* _C4 ) is a light cyan toner used in combination with a dark cyan toner having -10 to -28,
The light-colored cyan toner contains at least a binder resin and a colorant, and when a toner-fixed image on plain paper is represented by an L ^* a ^* b ^* -based color system, a when b ^* is -20 ^* a value _{^(a * C1)} is -19 to -30, light cyan ^{toner a *} values when the ^{b *} is -30 _{^(a * C2)} is characterized in that it is a -29 to -45 . The difference between a ^* _C1 and a ^* _C3 (a ^* _C1− a ^* _C3 ) is −22 to −1, and the difference between a ^* _C2 and a ^* _C4 (a ^* _C2− a ^* _C4 ) is −. 21. The light-colored cyan toner according to claim 20, wherein the number is from 33 to -1. The difference between a ^* _C1 and a ^* _C3 (a ^* _C1− a ^* _C3 ) is −12 to −3, and the difference between a ^* _C2 and a ^* _C4 (a ^* _C2− a ^* _C4 ) is −. 21. The light-colored cyan toner according to claim 20, which is 15 to -3. The a ^* _C1 is -26 to -21, the a ^* _C2 is -37 to -30, the a ^* _C3 is -18 to -11, and the a ^* _C4 is -27 to -20. , The difference between a ^* _C1 and a ^* _C3 (a ^* _C1− a ^* _C3 ) is −12 to −3, and the difference between a ^* _C2 and a ^* _C4 (a ^* _C2− a ^* _C4 ) is − 21. The light-colored cyan toner according to claim 20, which is 15 to -3. Forming an electrostatic image on the charged electrostatic image carrier,
A step of developing the formed electrostatic image with toner to form a toner image;
Transferring the formed toner image to a transfer material;
Fixing the transferred toner image to a transfer material to form a fixed image, comprising:
The step of forming the electrostatic image includes forming a first electrostatic image that is developed with a first toner selected from a light cyan toner and a dark cyan toner; and forming a light cyan toner and a dark cyan toner. Forming a second electrostatic image that is developed with a second toner other than the first toner, selected from toner.
The step of forming a toner image includes developing a first electrostatic image with a first toner to form a first cyan toner image, and developing a second electrostatic image with a second toner. Forming a second cyan toner image by
The transferring step includes transferring the first cyan toner image and the second cyan toner image to a transfer material, and forming a cyan toner image on which these toner images are superimposed on the transfer material,
The light-colored cyan toner and the dark-colored cyan toner contain at least a binder resin and a colorant, and a hue in the red-green direction is a ^* , a hue in the yellow-blue direction is b ^*, and lightness is L ^* . When a toner-fixed image on plain paper is represented by an L ^* a ^* b ^* color system,
The pale cyan toner has a value _{^(a * C1)} is -19 to -30 of ^{a *} when the ^{b *} is -20 in the fixed image of the pale cyan toner, ^{b *} is at a -30 ^{a *} of The value (a ^* _C2 ) is -29 to -45,
The dark cyan toner has a ^* value (a ^* _C3 ) of -7 to -18 when b ^* is -20 in the fixed image of the dark cyan toner, and a when b ^* is -30. An image forming method, wherein the value of ^* (a ^* _C4 ) is -10 to -28. The image forming method according to claim 24, wherein the fixing step is a heating and pressing step. The step of forming the electrostatic image includes forming a magenta electrostatic image developed with magenta toner, forming a yellow electrostatic image developed with yellow toner, and developing with a black toner. Forming a static charge image for black,
Forming the toner image, forming a magenta toner image by developing the magenta electrostatic image with magenta toner, and forming a yellow toner image by developing the yellow electrostatic image with the yellow toner; Developing a black electrostatic image with black toner to form a black toner image,
In the transferring step, a magenta toner image, a yellow toner image, and a black toner image are transferred to a transfer material, and a full-color toner image in which the toner image and the cyan toner image are overlapped is formed on the transfer material. 26. The image forming method according to claim 24, further comprising a step. The transferring includes transferring a toner image of each color to an intermediate transfer member, forming a toner image on which the toner images are superimposed on the intermediate transfer member, and transferring the toner image formed on the intermediate transfer member to a transfer material. 27. The image forming method according to claim 24, further comprising the step of: The difference between a ^* _C1 and a ^* _C3 (a ^* _C1− a ^* _C3 ) is −22 to −1, and the difference between a ^* _C2 and a ^* _C4 (a ^* _C2− a ^* _C4 ) is −. The image forming method according to any one of claims 24 to 27, wherein the number is from 33 to -1. The difference between a ^* _C1 and a ^* _C3 (a ^* _C1− a ^* _C3 ) is −12 to −3, and the difference between a ^* _C2 and a ^* _C4 (a ^* _C2− a ^* _C4 ) is −. 28. The image forming method according to claim 24, wherein the number is from 15 to -3. A ^* _C1 is -26 to -21, a ^* _C2 is -37 to -30, a ^* _C3 is -18 to -11, and a ^* _C4 is -27 to -20. , The difference between a ^* _C1 and a ^* _C3 (a ^* _C1− a ^* _C3 ) is −12 to −3, and the difference between a ^* _C2 and a ^* _C4 (a ^* _C2− a ^* _C4 ) is − 28. The image forming method according to claim 24, wherein the number is from 15 to -3. The light cyan toner has an L ^* value of 85 to 90 when c ^* represented by the following formula is 30, and the dark cyan toner has an L ^* value of 74 when c ^* is 30. The image forming method according to any one of claims 24 to 30, wherein

32. The image forming method according to claim 24, wherein the light-color cyan toner has a hue angle of 214 to 226 [deg.], And the dark-color cyan toner has a hue angle of 228 to 260 [deg.]. . 33. The image forming method according to claim 24, wherein the light-color cyan toner and the dark-color cyan toner each include a pigment in the colorant. The light cyan toner contains 0.4 to 1.5% by mass of a colorant based on the total amount of the toner, and the dark cyan toner contains 2.5 to 8.5% by mass of the colorant based on the total amount of the toner. The image forming method according to any one of claims 24 to 33, comprising: The dark cyan toner, the optical density of the solid image toner amount on paper is 1 mg / cm ² of 1.5 to 2.5, wherein the light cyan toner, the toner amount on the paper at 1 mg / cm ² 35. The image forming method according to claim 24, wherein the optical density of a certain solid image is 0.82 to 1.35. The light cyan toner and the dark cyan toner each contain a charge control agent, and the ratio of the charge control agent content of the light cyan toner to the charge control agent content of the dark cyan toner is 0.60 to 0. The image forming method according to any one of claims 24 to 35, wherein the image forming method is .95. 37. The image forming method according to claim 24, wherein the weight average particle diameter of the light cyan toner and the weight average particle diameter of the dark cyan toner are each 3 to 9 [mu] m. The image forming apparatus according to any one of claims 24 to 37, wherein a ratio of a weight average particle diameter of the light cyan toner to a weight average particle diameter of the dark cyan toner is 1.05 to 1.40. Method. The light cyan toner and the dark cyan toner each have an inorganic fine powder selected from the group consisting of titania, alumina, silica, and a composite oxide thereof, and a specific surface area of the inorganic fine powder is measured by a BET method. Wherein the ratio of the specific surface area of the inorganic fine powder contained in the light cyan toner to the specific surface area of the inorganic fine powder contained in the dark cyan toner is 0.60 to 0.95. The image forming method according to any one of claims 24 to 38. 40. A light-colored two-component developer containing at least the light-colored cyan toner and carrier and a dark-colored two-component developer containing at least the dark cyan toner and carrier. 2. The image forming method according to 1., 40. The image forming method according to claim 24, wherein a light-colored one-component developer made of the light-colored cyan toner and a dark-colored one-component developer made of the dark-colored cyan toner are used. A light-colored magenta toner containing at least a binder resin and a colorant, and a dark-colored magenta toner containing at least a binder resin and a colorant, a toner kit having a separated state,
When the hue in the red-green direction is a ^* , the hue in the yellow-blue direction is b ^* , and the lightness is L ^* , the toner fixed image on plain paper is represented by an L ^* a ^* b ^* color system. the light magenta toner, light color ^{b *} values when the magenta toner ^{a *} is 20 in a fixed image of the _{^(b * M1)} is -18 to 0, ^{b *} values when the ^{a *} is 30 (b ^* _M2 ) is -26 to 0;
The dark magenta toner is a ^{b *} value _{^(b * M3)} is -16 to 2 when the ^{a *} is 20 in deep color magenta toner of the fixed image, ^{a *} is the value of ^{b *} in the case of 30 (B ^* _M4 ) is −24 to 3, the difference between b ^* _M1 and b ^* _M3 (b ^* _M1− b ^* _M3 ) is −8 to −1, and the difference between b ^* _M2 and b ^* _M4 is The difference (b ^* _M2- b ^* _M4 ) is from -12 to -1. The difference between b ^* _M1 and b ^* _M3 (b ^* _M1− b ^* _M3 ) is −7 to −1.5, and the difference between b ^* _M2 and b ^* _M4 (b ^* _M2− b ^* _M4 ). 43. The image forming method according to claim 42, wherein n is from -11 to -2. The difference between ^b _{* M1} and _{^{b * M3 (b * M1 -b}} * M3) is -7 to ^-2, the difference between _{b * M2} and _{^{b * M4 (b * M2 -b}} * M4) is - 43. The image forming method according to claim 42, wherein the number is from 10 to -2. B ^* _M1 is -13 to -4, b ^* _M2 is -15 to -5, b ^* _M3 is -12 to 0, and b ^* _M4 is -15 to 0 The image forming method according to any one of claims 42 to 44, wherein: The b ^* _M1 is -13 to -4, the b ^* _M2 is -15 to -5, the b ^* _M3 is -11 to -2, and the b ^* _M4 is -14 to -3. The image forming method according to any one of claims 42 to 44, wherein: The light-colored magenta toner and the dark-colored magenta toner have the same triboelectric charging characteristics, and the difference between the two-component tribo values of the two magenta toners is within 5 mC / kg in absolute value. 47. The toner kit according to any one of items 42 to 46. The light magenta toner, ^{when c *} represented by the following formula the value of ^{L *} in the case of 30 was ^L _{* ^M1,} the value of _{L * M1} is 78 to 90, wherein the deep color magenta toner , ^{when c *} is the value of ^{L *} in the case of 30 was ^L _{* ^M2,} the value of _{L * M2} is 74 to 87,
48. The toner kit according to claim 42, wherein the difference between L ^* _M1 and L ^* _M2 is 0.4 to 12.

When the hue angle of a solid solid image having a toner amount on paper of 0.5 mg / cm 2 is H * M1 , the light magenta toner has an H * M1 of 325 to 350 °, and the dark magenta toner is the hue angle in the fixed image toner amount on paper is 0.5 mg / cm 2 when the H * M2, H * M2 is 340 to 10 °, the angle between H * M1 and H * M2 49. The toner kit according to claim 42, wherein (H * M2- H * M1 ) is 2 to 30 [deg.]. 49. The toner kit according to claim 42, wherein the light-color magenta toner and the dark-color magenta toner each contain a pigment as the colorant. The light-colored magenta toner contains 0.4 to 1.5% by mass of a colorant based on the total amount of the toner, and the dark-colored magenta toner contains 2.5 to 8.5% by mass of the colorant based on the total amount of the toner. The toner kit according to any one of claims 42 to 50, further comprising: The dark magenta toner, the optical density of the solid image toner amount on paper is 1 mg / cm 2 of 1.5 to 2.5, the light magenta toner, the toner amount on the paper at 1 mg / cm 2 52. The toner kit according to claim 42, wherein an optical density of a certain solid image is 0.82 to 1.35. The light-color magenta toner and the dark-color magenta toner each include a charge control agent, and the ratio of the content of the light-color magenta toner charge control agent to the content of the dark-color magenta toner charge control agent is 0.60 to 0. 53. The toner kit according to claim 42, wherein 54. The toner kit according to claim 42, wherein the weight average particle diameter of the light-color magenta toner and the weight average particle diameter of the dark-color magenta toner are each 3 to 9 [mu] m. 55. The toner kit according to claim 42, wherein a ratio of a weight average particle diameter of the light color magenta toner to a weight average particle diameter of the dark color magenta toner is 1.05 to 1.40. The light-colored magenta toner and the dark-colored magenta toner each have an inorganic fine powder selected from the group consisting of titania, alumina, silica, and a composite oxide thereof, and have a light color with respect to the specific surface area of the dark-colored magenta toner. The toner kit according to any one of claims 42 to 55, wherein a ratio of a specific surface area value of the magenta toner is 0.60 to 0.95. The light-colored two-component developer containing at least the light-colored magenta toner and the carrier, and the dark-colored two-component developer containing at least the dark-colored magenta toner and the carrier are used. 2. The image forming method according to 1., The toner kit according to any one of claims 42 to 56, comprising: a light-colored one-component developer made of the light-colored magenta toner; and a dark-colored one-component developer made of the dark-colored magenta toner. Containing at least a binder resin and a colorant, red - the hue of green direction and a *, yellow - the blue direction of the hue and b *, L * a * b * color system of the lightness and L * when showing the toner fixed image on plain paper, b * values when the a * is 20 in a fixed image (b * M1) is -18 to 0, b * values when the a * is 30 ( b * M2 ) is a dark magenta toner used in combination with a light magenta toner having a value of −26 to 0,
The concentration color magenta toner contains at least a binder resin and a colorant, when representing the L * a * b * system tables toner fixed image on plain paper by the color system, a * is at a 20 b * of the value (b * M3) is -16 to 2, b * values when the a * is 30 (b * M4) is -24 to 3, the difference between b * M1 and b * M3 (b * M1 -b * M3) is -8 to -1, b * M2 and b * difference between M4 (b * M2 -b * M4 ) dark, characterized in that it is -12 to -1 Magenta toner. The difference between b * M1 and b * M3 (b * M1 -b * M3) is -7 to -1, the difference between b * M2 and b * M4 (b * M2 -b * M4) is - 60. The dark magenta toner according to claim 59, wherein the number is from 11 to -2. The difference between b * M1 and b * M3 (b * M1 -b * M3) is -7 to -2, the difference between b * M2 and b * M4 (b * M2 -b * M4) is - 60. The dark magenta toner according to claim 59, wherein the number is from 10 to -2. B * M1 is -13 to -4, b * M2 is -15 to -5, b * M3 is -12 to 0, and b * M4 is -15 to 0 63. The dark magenta toner according to any one of claims 59 to 61. The b * M1 is -13 to -4, the b * M2 is -15 to -5, the b * M3 is -11 to -2, and the b * M4 is -14 to -3. 63. The dark magenta toner according to any one of claims 59 to 61. Containing at least a binder resin and a colorant, red - the hue of green direction and a *, yellow - the blue direction of the hue and b *, L * a * b * color system of the lightness and L * when showing the toner fixed image on plain paper, b * values when the a * is 20 in a fixed image (b * M3) is -16 to 2, b * values when the a * is 30 ( b * M4 ) is a light-colored magenta toner used in combination with a dark-colored magenta toner having -24 to 3;
該淡color magenta toner contains at least a binder resin and a colorant, b * values when the a * is 20 in a fixed image (b * M1) is -18 to 0 when a * is 30 the b * value (b * M2) is -26 to 0, b * M1 and the difference between the b * M3 (b * M1 -b * M3) is -8 to -1, and b * M2 pale magenta toner, wherein a difference between the b * M4 (b * M2 -b * M4) is -12 to -1. The difference between b * M1 and b * M3 (b * M1 -b * M3) is -7 to -1, the difference between b * M2 and b * M4 (b * M2 -b * M4) is - 65. The light-colored magenta toner according to claim 64, wherein the number is from 11 to -2. The difference between b * M1 and b * M3 (b * M1 -b * M3) is -7 to -2, the difference between b * M2 and b * M4 (b * M2 -b * M4) is - 65. The light-colored magenta toner according to claim 64, wherein the number is from 10 to -2. B * M1 is -13 to -4, b * M2 is -15 to -5, b * M3 is -12 to 0, and b * M4 is -15 to 0 The light-colored magenta toner according to any one of claims 64 to 66, wherein: The b * M1 is -13 to -4, the b * M2 is -15 to -5, the b * M3 is -11 to -2, and the b * M4 is -14 to -3. 67. The light-color magenta toner according to claim 64. Forming an electrostatic image on the charged electrostatic image carrier,
A step of developing the formed electrostatic image with toner to form a toner image;
An image forming method, comprising: a step of transferring the formed toner image to a transfer material; and a step of forming a fixed image by heat-pressing and fixing the transferred toner image to a transfer material.
The step of forming the electrostatic image includes forming a first electrostatic image developed with a first toner selected from a light-colored magenta toner and a dark-colored magenta toner; and forming a light-colored magenta toner and a dark-colored magenta toner. Forming a second electrostatic image that is developed with a second toner other than the first toner, selected from toner.
The step of forming the toner image includes developing the first electrostatic image with the first toner to form a first magenta toner image, and developing the second electrostatic image with the second toner. Forming a second magenta toner image by
The transferring step includes transferring a first magenta toner image and a second magenta toner image to a transfer material, and forming a magenta toner image in which these toner images are superimposed on the transfer material,
The light-colored magenta toner and the dark-colored magenta toner contain at least a binder resin and a colorant, and the hue in the red-green direction is a * , the hue in the yellow-blue direction is b * , and the lightness is L * . When a toner-fixed image on plain paper is represented by an L * a * b * color system,
The light magenta toner, light color b * values when the magenta toner a * is 20 in a fixed image of the (b * M1) is -18 to 0, b * values when the a * is 30 (b * M2 ) is -26 to 0, and the dark magenta toner has a b * value (b * M3 ) of -16 to 2 when a * is 20 in a fixed image of the dark magenta toner; a * is the value of b * (b * M4) is -24 to 3 when 30, in b * M1 and b * difference between M3 (b * M1 -b * M3 ) is -8 to -1 There, an image forming method, wherein a difference between b * M2 and b * M4 (b * M2 -b * M4) is -12 to -1. The difference between b * M1 and b * M3 (b * M1 -b * M3) is -7 to -1, the difference between b * M2 and b * M4 (b * M2 -b * M4) is - 70. The image forming method according to claim 69, wherein the number is 11 to -2. The difference between b * M1 and b * M3 (b * M1 -b * M3) is -7 to -2, the difference between b * M2 and b * M4 (b * M2 -b * M4) is - The image forming method according to claim 69, wherein the number is 10 to -2. B * M1 is -13 to -4, b * M2 is -15 to -5, b * M3 is -12 to 0, and b * M4 is -15 to 0 The image forming method according to any one of claims 69 to 71, wherein: The b * M1 is -13 to -4, the b * M2 is -15 to -5, the b * M3 is -11 to -2, and the b * M4 is -14 to -3. 72. The image forming method according to claim 69, wherein: The light-colored magenta toner and the dark-colored magenta toner have the same triboelectric charging characteristics, and the difference between the two-component tribo values of the two magenta toners is within 5 mC / kg in absolute value. 74. The image forming method according to any one of items 69 to 73. The step of forming the electrostatic image includes forming a cyan electrostatic image developed with cyan toner, forming a yellow electrostatic image developed with yellow toner, and developing with a black toner. Forming a static charge image for black,
Forming the toner image, developing a cyan electrostatic image with cyan toner to form a cyan toner image, developing the yellow electrostatic image with yellow toner, and forming a yellow toner image; Developing a black electrostatic image with black toner to form a black toner image,
The step of transferring includes transferring a magenta toner image, a yellow toner image, and a black toner image to a transfer material, and forming a full-color toner image on which the toner image and the magenta toner image are superimposed on the transfer material. The image forming method according to any one of claims 69 to 74, comprising: The transferring includes transferring a toner image of each color to an intermediate transfer member, forming a toner image on which the toner images are superimposed on the intermediate transfer member, and transferring the toner image formed on the intermediate transfer member to a transfer material. The image forming method according to any one of claims 69 to 75, further comprising the step of: The light magenta toner, when c * represented by the following formula the value of L * in the case of 30 was L * M1, the value of L * M1 is 78 to 90, wherein the deep color magenta toner , when c * is the value of L * in the case of 30 was L * M2, the value of L * M2 is 74 to 87,
77. The image forming method according to claim 69, wherein a difference between L ^* _M1 and L ^* _M2 is 0.4 to 12.

When the hue angle of a solid solid image having a toner amount on paper of 0.5 mg / cm ² is H ^* _M1 , the light magenta toner has an H ^* _M1 of 325 to 350 °, and the dark magenta toner Is that when the hue angle in a fixed solid image in which the amount of toner on paper is 0.5 mg / cm ² is H ^* _M2 , H ^* _M2 is 340 to 10 °, and H ^* _M1 and H ^* _M2 are formed. The image forming method according to any one of claims 69 to 77, wherein the angle (H ^* _M2- H ^* _M1 ) is 2 to 30 °. 79. The image forming method according to claim 69, wherein each of the light-color magenta toner and the dark-color magenta toner contains a pigment in the colorant. The light-colored magenta toner contains 0.4 to 1.5% by mass of a colorant based on the total amount of the toner, and the dark-colored magenta toner contains 2.5 to 8.5% by mass of the colorant based on the total amount of the toner. The image forming method according to any one of claims 69 to 79, further comprising: The dark magenta toner, the optical density of the solid image toner amount on paper is 1 mg / cm ² of 1.5 to 2.5, the light magenta toner, the toner amount on the paper at 1 mg / cm ² The image forming method according to any one of claims 69 to 80, wherein the optical density of a certain solid image is 0.82 to 1.35. The light-color magenta toner and the dark-color magenta toner each include a charge control agent, and the ratio of the content of the light-color magenta toner charge control agent to the content of the dark-color magenta toner charge control agent is 0.60 to 0. The image forming method according to any one of claims 69 to 81, wherein the image forming method is .95. 83. The image forming method according to claim 69, wherein the weight average particle diameter of the light color magenta toner and the weight average particle diameter of the dark color magenta toner are each 3 to 9 [mu] m. 84. The image forming apparatus according to claim 69, wherein a ratio of a weight average particle diameter of the light magenta toner to a weight average particle diameter of the dark magenta toner is 1.05 to 1.40. Method. The light-colored magenta toner and the dark-colored magenta toner each have an inorganic fine powder selected from the group consisting of titania, alumina, silica, and a double oxide thereof, and a specific surface area of the inorganic fine powder is measured by a BET method. Wherein the ratio of the specific surface area of the inorganic fine powder contained in the light-colored magenta toner to the specific surface area of the inorganic fine powder contained in the dark-colored magenta toner is 0.60 to 0.95. The image forming method according to any one of claims 69 to 84. 86. A light-colored two-component developer containing at least the light-colored magenta toner and a carrier, and a dark-colored two-component developer containing at least the dark-colored magenta toner and a carrier. 2. The image forming method according to 1., 86. The image forming method according to claim 69, wherein a light-color one-component developer made of the light-color magenta toner and a dark-color one-component developer made of the dark-color magenta toner are used. A light cyan toner containing at least a binder resin and a colorant, a dark cyan toner containing at least a binder resin and a colorant, a light magenta toner containing at least a binder resin and a colorant, and at least a binder resin And a dark magenta toner containing a colorant, and a toner kit having in a separated state,
When the hue in the red-green direction is a ^* , the hue in the yellow-blue direction is b ^* , and the lightness is L ^* , the toner fixed image on plain paper is represented by an L ^* a ^* b ^* color system.
The pale cyan toner has a value _{^(a * C1)} is -19 to -30 of ^{a *} when the ^{b *} is -20 in the fixed image of the pale cyan toner, ^{b *} is at a -30 ^{a *} of The value (a ^* _C2 ) is -29 to -45,
The deep color cyan toner has a value _{^(a * C3)} is -7 to -18 ^{a *} when the ^{b *} is -20 in dark cyan toner of the fixed image, ^{b *} is -30 a time of The value of ^* (a ^* _C4 ) is -10 to -28,
The light magenta toner, light color ^{b *} values when the magenta toner ^{a *} is 20 in a fixed image of the _{^(b * M1)} is -18 to 0, ^{b *} values when the ^{a *} is 30 (b ^* _M2 ) is -26 to 0;
The dark magenta toner is a ^{b *} value _{^(b * M3)} is -16 to 2 when the ^{a *} is 20 in deep color magenta toner of the fixed image, ^{a *} is the value of ^{b *} in the case of 30 (B ^* _M4 ) is −24 to 3, the difference between b ^* _M1 and b ^* _M3 (b ^* _M1− b ^* _M3 ) is −8 to −1, and the difference between b ^* _M2 and b ^* _M4 is The difference (b ^* _M2- b ^* _M4 ) is from -12 to -1. Forming an electrostatic image on the charged electrostatic image carrier,
A step of developing the formed electrostatic image with toner to form a toner image;
Transferring the formed toner image to a transfer material;
Forming a fixed image by heating and pressing the transferred toner image on a transfer material to form a fixed image,
The step of forming the electrostatic image is a first electrostatic image developed with a first toner selected from a toner group consisting of a light cyan toner, a dark cyan toner, a light magenta toner, and a dark magenta toner. Forming a second electrostatic image developed with a second toner other than the first toner selected from the toner group; and selecting a first electrostatic image from the toner group. Forming a third electrostatic image developed with a third toner other than the second toner, and developing with a fourth toner other than the first to third toners selected from the toner group Forming a fourth electrostatic image to be performed,
The step of forming the toner image includes developing a first electrostatic image with a first toner to form a first toner image, and developing a second electrostatic image with a second toner. Forming a second toner image, developing the third electrostatic image with the third toner to form a third toner image, and developing the fourth electrostatic image with the fourth toner Forming a fourth toner image by
The transferring step includes transferring the first toner image, the second toner image, the third toner image, and the fourth toner image onto a transfer material, and forming a color toner image on which these toner images are superimposed. Including a step of forming on a transfer material,
The light-colored cyan toner, the dark-colored cyan toner, the light-colored magenta toner, and the dark-colored magenta toner each contain at least a binder resin and a colorant, and have a hue in the red-green direction as a ^* , and a yellow-blue color. When a toner-fixed image on plain paper is represented by an L ^* a ^* b ^* -based color system in which the hue in the direction is b ^* and the lightness is L ^* ,
The pale cyan toner has a value _{^(a * C1)} is -19 to -30 of ^{a *} when the ^{b *} is -20 in the fixed image of the pale cyan toner, ^{b *} is at a -30 ^{a *} of The value (a ^* _C2 ) is -29 to -45,
The deep color cyan toner has a value _{^(a * C3)} is -7 to -18 ^{a *} when the ^{b *} is -20 in dark cyan toner of the fixed image, ^{b *} is -30 a time of The value of ^* (a ^* _C4 ) is -10 to -28,
The light magenta toner, light color ^{b *} values when the magenta toner ^{a *} is 20 in a fixed image of the _{^(b * M1)} is -18 to 0, ^{b *} values when the ^{a *} is 30 (b ^* _M2 ) is -26 to 0;
The dark magenta toner is a ^{b *} value _{^(b * M3)} is -16 to 2 when the ^{a *} is 20 in deep color magenta toner of the fixed image, ^{a *} is the value of ^{b *} in the case of 30 (B ^* _M4 ) is −24 to 3, the difference between b ^* _M1 and b ^* _M3 (b ^* _M1− b ^* _M3 ) is −8 to −1, and the difference between b ^* _M2 and b ^* _M4 is An image forming method, wherein the difference (b ^* _M2- b ^* _M4 ) is from -12 to -1.

Images