JP2004004387A - Urethane-modified polyester resin containing release agent for toner, toner for developing electrostatic images using the same, and two-component electrophotographic developer - Google Patents

Abstract

An object of the present invention is to provide a toner and a developer for developing an electrostatic image, which have good chargeability, image density, low-temperature fixing property, anti-offset property, anti-blocking property and good dispersibility of a release agent. To provide. Another object of the present invention is to provide a urethane-modified polyester resin containing a release agent used for a toner for developing an electrostatic image and a developer.
A number average molecular weight measured by gel permeation chromatography (GPC) when a polyester resin for polymerization (A), a low molecular weight polyester resin (B) and a polyvalent isocyanate compound are mixed and reacted. (Mn) is from 800 to 2,000, and a release agent for toner obtained by adding an ethylene homopolymer having a value of weight average molecular weight / number average molecular weight (Mw / Mn) of 1.5 or less as a release agent. Agent-containing urethane-modified polyester resin.

Description

【００１１】
一方、ジカルボン酸としては、従来ポリエステル樹脂を製造する際に用いられているものをいずれも用いることができ、好ましいものとしては、例えばマロン酸、コハク酸、グルタル酸、アジピン酸、セバシン酸、アゼライン酸などのアルキルジカルボン酸類、マレイン酸、フマル酸、シトラコン酸、イタコン酸などの不飽和ジカルボン酸、フタル酸、テレフタル酸、イソフタル酸、無水フタル酸などのベンゼンジカルボン酸類、これらジカルボン酸の無水物或いは低級アルキルエステルなどを挙げることができる。また、三価以上の多価アルコール成分としては、グリセリン、２−メチルプロパントリオール、トリメチロールプロパン、トリメチロールエタン、ソルビット、ソルビタンなどを例示することができる。三価以上の多価アルコール成分は、通常全原料モノマーを基準にして０．５モル％未満である場合には高分子化しづらく、耐オフセット性が不十分なものとなりがちであり、また逆に２０モル％を超えるとゲル化しやすくなり重縮合し難くなるため、０．５〜２０モル％の量で用いることが好ましく、２〜２０モル％がより好ましい。
【００１２】
また、長鎖脂肪族モノカルボン酸としては、オクタン酸、デカン酸、ドデカン酸、ミリスチン酸、パルミチン酸、ステアリン酸等の炭素数が８から２２の脂肪族モノカルボン酸が挙げられ、分岐や不飽和基を有していてもよい。更に、長鎖脂肪族モノアルコールとしては、オクタノール、デカノール、ドデカノール、ミリスチルアルコール、パルミチルアルコール、ステアリルアルコールなどの炭素数が８から２２の脂肪族モノアルコールが挙げられる。長鎖脂肪族モノカルボン酸または長鎖脂肪族モノアルコールの使用量は、全原料モノマーを基準にして２〜２０モル％の量が好ましく、２モル％未満では巻き付き防止性や離型剤分散の効果は少なく、２０モル％を超える量ではモノ官能基化合物が重合を阻害し、高分子化しにくくなるため好ましくない。長鎖脂肪族は、ガラス転移点を下げる性質があるため、ガラス転移点調節のため、安息香酸やナフタレンカルボン酸などの芳香族モノカルボン酸を用いてもよい。なお、必要であれば、三価以上の多価カルボン酸を用いることも可能であり、高分子化用ポリエステル樹脂（Ａ）の原料として三価以上の多価カルボン酸が排除されるものではない。
【００１３】
一方、低分子ポリエステル樹脂（Ｂ）は、その製造法、合成原料の如何を問わず、何れのものも用いることができるが、水酸基価が１０　ＫＯＨｍｇ／ｇ以下で、かつ重量平均分子量が３，０００〜５，０００であることが好ましい。ここにおいて、低分子ポリエステル樹脂（Ｂ）の重量平均分子量が３，０００未満であると、形成されたトナーのオフセット性に問題が生じ好ましくない。また、定着性の観点から重量平均分子量が５，０００以下の方がより好ましい。この低分子ポリエステル樹脂（Ｂ）として好ましいものとしては、少なくとも１種のジオールと少なくとも１種のジカルボン酸、必要に応じ少なくとも１種のモノカルボン酸を用いて製造された線状ポリエステル樹脂が挙げられる。低分子ポリエステル樹脂（Ｂ）の製造に用いられるジオール及びジカルボン酸として好ましい化合物としては、上記高分子化用ポリエステル樹脂（Ａ）を製造するための原料として挙げられたものと同じものを挙げることができる。また、モノカルボン酸としては、オクタン酸、デカン酸、ドデカン酸、ミリスチル酸、パルミチン酸、ステアリン酸などの炭素数が８〜２２の脂肪族モノカルボン酸、安息香酸などの芳香族モノカルボン酸などを例示することができ、特に安息香酸が好ましい。
【００１４】
上記高分子化用ポリエステル樹脂（Ａ）及び低分子ポリエステル樹脂（Ｂ）を得る際の重縮合反応は、窒素ガス等の不活性ガス中での、例えば無溶剤下高温重縮合、溶液重縮合等の公知の方法により行うことができる。反応に際してのカルボン酸（ジカルボン酸、モノカルボン酸など）とアルコール（モノアルコール、ジオール、三官能アルコールなど）の使用割合は、前者のカルボキシル基に対する後者の水酸基の割合で０．７〜１．４であることが一般的である。
【００１５】
本発明のトナー用離型剤含有ウレタン変性ポリエステル樹脂は、高分子化用ポリエステル樹脂（Ａ）及び低分子ポリエステル樹脂（Ｂ）を多価イソシアネート化合物と反応させ、その際に離型剤を添加することにより製造されるが、その際低分子ポリエステル樹脂（Ｂ）の量が多くなると、静電荷像現像用トナーのバインダー樹脂として用いたときトナーのオフセット性が悪くなる傾向があり、また高分子化用ポリエステル樹脂（Ａ）の量が多くなると、トナーの低温定着性が悪くなる傾向がある。このため、高分子化用ポリエステル樹脂（Ａ）と低分子ポリエステル樹脂（Ｂ）の混合比は重量割合で、高分子化用ポリエステル樹脂（Ａ）：低分子ポリエステル樹脂（Ｂ）が３〜５：７〜５であるものが最も好ましい。
また、高分子化用ポリエステル樹脂（Ａ）と低分子ポリエステル樹脂（Ｂ）とのトータル酸価が２０　ＫＯＨｍｇ／ｇを超えると、得られた離型剤含有ウレタン変性ポリエステル樹脂を含有するトナーの帯電量が低く、また高温高湿時でなくとも十分な濃度を有する現像画像を形成することが困難な場合がある。またトータル酸価が５　ＫＯＨｍｇ／ｇよりも小さくなると離型剤の分散粒径が大きくなってしまい、均一に分散することが困難になってしまう場合がある。
【００１６】
一方、上記多価イソシアネート化合物としては、例えばヘキサメチレンジイソシアネート、イソホロンジイソシアネート、トリレンジイソシアネート、ジフェニルメタンジイソシアネート、キシリレンジイソシアネート、テトラメチレンジイソシアネートなどのジイソシアネート、下記（１）〜（５）で表されるイソシアネートを挙げることができる。
【００１７】
【化２】

【００１８】
これら多価イソシアネートの使用量は、通常全ポリエステル樹脂の水酸基１当量あたり、イソシアネート基として０．２〜１．２当量の量であり、好ましくは０．３〜１．０当量の量である。
【００１９】
本発明で好ましく用いることのできる離型剤は完全飽和のエチレンホモポリマーである。
エチレンホモポリマーの分子量は、数平均分子量（Ｍｎ）が８００〜２０００であることが好ましい。数平均分子量（Ｍｎ）が８００よりも小さいと、熱的影響を過度に受けやすく、耐ブロッキング性、画像濃度低下などの現像性に劣るようになってしまう場合があり、一方数平均分子量（Ｍｎ）が２０００よりも大きいと、外部からの熱を効果的に利用できず、優れた定着性、耐オフセット性を得るのが困難になってしまう場合がある。
また重量平均分子量（Ｍｗ）と数平均分子量（Ｍｎ）との比であるＭｗ／Ｍｎは１．５以下、好ましくは１．３以下であることが好ましい。Ｍｗ／Ｍｎは分子量分布の分散度を表すものであり、この数値が小さいほど、分子量分布が狭く分子が均一であり、相溶性に優れ、離型剤を樹脂中に良好に分散させる上で好ましい。
これにより本発明の特性を有するポリエチレンホモポリマーは、ウレタンポリエステル樹脂との混合においても相溶性に優れ、良好な分散状態を得ることができる。これによりウレタン変性ポリエステル樹脂中の該離型剤の平均分散粒径が１．０μｍ以下と良好な平均分散粒径が得られる。
【００２０】
本発明の離型剤の粒子径は１００μｍ以下であることが好ましい。１００μｍよりも大きいとワックス分散粒径が大きくなってしまうポリエステル樹脂への分散、分配が困難になってしまい、トナーの品位に支障をきたしてしまう。
【００２１】
離型剤の添加量はウレタン変性ポリエステル樹脂１００重量部に対して０．５〜１０重量部が好ましい。更に好ましくは１〜６重量部である。１重量部以下では離型剤を添加する効果は得られず、一方１０重量部よりも多くなるとウレタン変性ポリエステル樹脂との相溶性に問題を生じてしまうことがある。また離型剤が過剰になると、離型剤がトナー中に偏在し、トナーを微粉砕する際に離型剤が遊離し、遊離した離型剤による感光体、現像スリーブ、キャリアへのフィルミングなどの問題が発生してしまう可能性がある。
【００２２】
これらの反応は、高分子化用ポリエステル樹脂（Ａ）、低分子ポリエステル樹脂（Ｂ）及び多価イソシアネート化合物を混合し、更に離型剤を添加して、溶融混合することにより行われるれるが、高分子化用ポリエステル樹脂（Ａ）の溶融物と低分子ポリエステル樹脂（Ｂ）の溶融物を混練し、この混練物に多価イソシアネート化合物と離型剤とを添加し、溶融混練する方法が好ましい。この溶融混合を行うための具体的方法としては高分子化用ポリエステル樹脂（Ａ）と低分子ポリエステル樹脂（Ｂ）との混合物を二軸押出機に一定スピードで注入し、同時に多価イソシアネートと離型剤も一定速度で注入する、或いは二軸押出機の送り方向に対し順次低分子ポリエステル樹脂（Ｂ）、高分子化用ポリエステル樹脂（Ａ）、多価イソシアネート及び離型剤を注入し、例えば１００〜２００℃の温度で混練搬送しながら反応及び混合を行わせるなどの方法が採用できる。このとき、二軸押出機に投入、或いは注入される反応原料である低分子ポリエステル樹脂（Ｂ）及び高分子化用ポリエステル樹脂（Ａ）は、各々ポリエステル樹脂反応容器から冷却することなくそのまま直接押出機に注入するようにしてもよいし、また一旦製造した樹脂を冷却、破砕或いはビーズ化したものを二軸押出機に供給することによりおこなってもよい。しかし、本発明では、離型剤含有ウレタン変性ポリエステル樹脂を製造する方法がこれら具体的に例示された方法に限られるわけではなく、従来公知の方法例えば反応容器中に原料を仕込み、溶液状態となる温度に加熱し、混合するような方法など適宜の方法で行うことができることは勿論である。本発明に用いられ離型剤含有ウレタン変性ポリエステル樹脂は、０．１〜２５％のゲル分を含有するものが好ましい。このゲル分は、樹脂５ｇを酢酸エチル１００ｍｌに４時間混合し、その後１昼夜放置した後、上澄液をスポイトにて静かに採取し、得られた溶解ポリマー量を不揮発分にて測定して得られたものである。
【００２３】
本発明において結着樹脂、離型剤成分などの分子量分布はＧＰＣにより次の条件で測定される。
【００２４】
装置：ＧＰＣ−１５０Ｃ（ウォーターズ社）
カラム：ＧＭＨ−ＨＴ３０ｃｍ２連（東ソ−社製）
温度：１３５℃
溶媒：ｏ−ジクロロベンゼン（０．１％アイオノール添加）
流速：１．０ｍｌ／ｍｉｎ
試料：０．１５％の試料を０．４ｍｌ注入
【００２５】
以上の条件で測定し、試料の分子量算出にあたっては単分散ポリスチレン標準試料により作成した分子量較正曲線を使用する。さらに、Ｍａｒｋ−Ｈｏｕｗｉｎｋ粘度式から導き出される換算式でポリエチレン換算することによって算出される。
【００２６】
なお、本発明において、酸価は、樹脂１ｇを中和するために必要な水酸化カリウムのｍｇ数をいい、また、水酸基価は、樹脂の水酸基と無水フタル酸とを反応させ、その反応に要した酸を、該樹脂１ｇ当り中和するために必要な水酸化カリウムのｍｇ数をいう。
【００２７】
ウレタン変性ポリエステル樹脂中の離型剤の分散粒径の測定については以下の手順で試料を作製し透過型電子顕微鏡を用いて分散粒径を求めた。離型剤含有ウレタン変性ポリエステル樹脂を電子線に対して強度の強い樹脂、例えばエポキシ樹脂で包含して試料を固定した後、ミクロトームを用いて透過型電子顕微鏡観察用の試料を作製した。この時ミクロトームのナイフはダイアモンドナイフを用いた。またオスミウムを用いて離型剤部分の染色を行なった。得られた試料を透過型電子顕微鏡で観察し、ウレタン変性ポリエステル樹脂中に分散される離型剤の粒径を測定した。この時粒径を測定する方法としては写真を用いて測定するだけでなく画像解析装置を用いても良い。本発明においては任意の１００個の分散している離型剤を抽出して粒径（最大長径）を求めその平均値を求め、平均粒径とした。
【００２８】
ウレタン変性ポリエステル樹脂中の離型剤の分散粒径は１μｍ以下であることが好ましい。さらに好ましくは０．８μｍ以下である。離型剤の分散粒径は１μｍ以下であればトナー中に良好な離型剤の分散を施すことができ、良好な品質が得られる。１μｍ以下であればウレタン変性ポリエステル中に均一に分散して、トナー化しても良好な分散性、分配性を保持することができる。
一方１μｍより大きくなるとウレタン変性ポリエステル樹脂中に離型剤の良好な分散を施すことが困難になり、さらに個々のトナー粒子に均一に離型剤を分配することが困難になってしまう。分配不良が生じる場合は、特に粒径の細かい分級微粉の方に離型剤含有量が多く、また単独の離型剤が存在している。
このように離型剤の分散、分配不良が生じてしまうとかぶりが増大する等良好な画像が得られなかったり、分配不良による配合量の偏りのためトナー製造時に分級微粉のリサイクルができなくなってしまいコスト高に繋がってしまう等の問題が生じてしまう。
【００２９】
本発明の静電荷像現像用トナーにおいては、上記離型剤含有ウレタン変性ポリエステル樹脂の他に、必要に応じそれ以外の公知の他のバインダー樹脂、荷電制御剤、着色剤、他の離型剤、外添剤等トナーを製造する際に通常用いられる材料を含有せしめることができる。
【００３０】
上記離型剤含有ウレタン変性ポリエステル樹脂とともに用いることのできる他のバインダー樹脂としては、従来静電荷像現像用トナーのバインダー樹脂として公知のものであればいずれでもよく、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などのスチレン及びその置換体の単重合体；スチレン−ｐ−クロルスチレン共重合体、スチレン−ビニルトルエン共重合体、スチレン−ビニルナフタレン共重合体、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−インデン共重合体などの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、上記ウレタン変性ポリエステル樹脂以外のポリエステル樹脂、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、架橋されたスチレン系共重合体などの樹脂が挙げられる。
【００３１】
本発明に用いられる着色剤としては、従来トナー粒子の着色剤として用いられている染料および顔料のいずれのものをも用いることができ、以下に示す黒、イエロー、マゼンタ、シアンの各着色剤が好適に用いられる。また磁性トナーの場合は磁性粉も着色剤として用いられる。
【００３２】
黒の着色剤としては、カーボンブラック、アニリンブラック、アセチレンブラック、鉄黒等が好適に用いられる。本発明において使用できるカーボンブラックはファーネスブラックとチャンネルブラックの２種類に大別することができる。これらの種類、添加量により、トナーの電気的物性、摩擦帯電性が影響を受ける。これらの着色剤は、単独で或いは２種以上を混合して使用することができ、通常結着樹脂の１００重量部に対し、０．１〜２０重量部、好ましくは０．３〜１０重量部の添加量がよい。
【００３３】
また磁性トナーに用いる磁性粉の場合は、マグネタイト、マグヘマイト、フェライト等の酸化鉄または二価金属と酸化鉄との化合物、鉄、コバルト、ニッケルのような金属或いはこれらの金属のアルミニウム、コバルト、銅、鉛、マグネシウム、スズ、亜鉛、アンチモン、ベリリウム、ビスマス、カドミウム、カルシウム、マンガン、セレン、チタン、タングステン、バナジウムのような金属の合金の粉体及びこれらの混合物があげられる。これらの磁性材料は平均粒径が０．０５〜２．０μｍ、好ましくは０．１〜０．５μｍ程度のものが望ましく、磁性トナー中に含有させる量としては結着樹脂１００重量部に対して５〜１５０重量部、好ましくは１０〜１２０重量部である。また必要に応じて磁性材料と着色剤を併用して用いることもできる。着色剤としては、例えばカーボンブラック、銅フタロシアニン、鉄黒などが用いられる。
【００３４】
イエローの着色剤としては、縮合アゾ化合物、イソインドリノン化合物、アントラキノン化合物、アゾ金属錯化合物、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用いられる。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等が好適に用いられる。これら着色剤は、単独で或いは２種以上を混合して使用することができ、通常結着樹脂の１００重量部に対し、０．１〜２０重量部、好ましくは０．３〜１０重量部の添加量がよい。
【００３５】
マゼンタの着色剤としては、縮合アゾ化合物、ジケトピロロピロール化合物、アントラキノン、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、ペリレン化合物が用いられる。具体的には、Ｃ．Ｉ．ピグメントレッド２、３、５、６、７、２３、４８：２、４８：３、４８：４、５７：１、８１：１、１２２、１４４、１４６、１６６、１６９、１７７、１８４、１８５、２０２、２０６、２２０、２２１、２５４等が好適に用いられる。これら着色剤は、単独で或いは２種以上を混合して使用することができ、通常結着樹脂の１００重量部に対し、０．１〜２０重量部、好ましくは０．３〜１０重量部の添加量がよい。
【００３６】
シアンの着色剤としては、銅フタロシアニン化合物及びその誘導体、アントラキノン化合物、塩基染料レーキ化合物等が利用できる。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等が好適に用いられる。これら着色剤は、単独で或いは２種以上を混合して使用することができ、通常結着樹脂の１００重量部に対し、０．１〜２０重量部、好ましくは０．３〜１０重量部の添加量がよい。
【００３７】
また着色剤を結着樹脂に分散させる方法としては、フラッシュ法により予め着色剤を高濃度に含む樹脂チップを製造し、これを結着樹脂と混合、混練する方法などを含め、従来から公知のいずれの方法をも採用することができる。
【００３８】
またトナー中の帯電量を安定に制御する目的で荷電制御剤を使用することもできる。荷電制御剤としては、従来静電荷像現像用トナーの荷電制御剤として知られたものの何れのものも使用できる。荷電制御剤は、現像されるべき静電潜像担持体上の静電荷像の極性に応じて、正荷電制御剤または負荷電制御剤が選択されるが、正荷電制御剤としては、例えば、ニグロシン染料、脂肪酸金属誘導体、トリフェニルメタン系染料、４級アンモニウム塩（例えば、トリブチルベンジルアンモニウム−１−ヒドロキシ−４−ナフトスルホン酸塩、テトラブチルベンジルアンモニウムテトラフルオロボレート）、ジオルガノスズオキサイド（例えば、ジブチルスズオキサイド、ジオクチルスズオキサイド、ジシクロヘキシルスズオキサイド）、ジオルガノスズボレート（ジブチルスズボレート、ジオクチルスズボレート、ジシクロヘキシルスズボレート）等が挙げられ、これらは単独であるいは二種以上組合わせて用いることができる。これらの中でも、ニグロシン系、４級アンモニウム塩及びトリフェニルメタン系染料が好ましい。一方、負荷電制御剤としては、カルボキシル基を有する化合物、例えばサリチル酸あるいはサリチル酸誘導体の金属塩や金属キレート（錯体）、金属錯塩染料、脂肪酸石鹸、ナフテン酸金属塩等が挙げられる。これら荷電制御剤は、通常結着樹脂１００重量部に対して０．１〜８重量部、好ましくは０．５〜６重量部の割合で使用される。
【００３９】
本発明の静電荷像現像用トナーの調製方法については特に制限はなく、従来公知の方法により適宜調製することができる。トナー調整法の一例を示すと、前記のトナー構成成分を、乾式ブレンダー、ヘンシェルミキサー、ボールミル等により予備混合し、しかる後、この混合物を熱ロールニーダー、一軸または二軸のエクストルーダー等の熱混練機によって溶融混練し、得られた混練物を冷却後ハンマーミルなどの粉砕機を用いて機械的に粗粉砕し、次いでジェット粉砕機などで微粉砕した後、必要に応じ所望の粒径に分級する方法により製造する方法が好ましい方法として挙げられる。
【００４０】
本発明のトナーの粒径としては、重量平均粒径が３〜１５μｍのものが好ましい。特に、５μｍ以下の粒径を有するトナー粒子が１２〜６０個数％含有され、８〜１２．７μｍの粒径を有するトナー粒子が１〜３３個数％含有され、１６μｍ以上の粒径を有するトナー粒子が２．０重量％以下含有され、トナーの重量平均粒径が４〜１０μｍであることが、現像特性の上からはより好ましい。なお、トナーの粒度分布測定は、例えばコールターカウンターを用いて測定することができる。
【００４１】
本発明の現像剤が絶縁性磁性トナーである場合には、１０^１０Ω・ｃｍ以上、好ましくは１０^１３Ω・ｃｍ以上の電気抵抗を有することが好ましい。このようにして調製された静電荷像現像用トナーは、必要に応じ外添剤と混合される。
【００４２】
本発明のトナーは、さらに必要に応じて離型剤、滑剤、流動化剤、研磨剤、導電性付与剤、画像剥離防止剤等のトナーの製造に当たり使用されている公知の添加剤を外添剤として使用することができる。
具体的には、滑剤としては、例えばポリテトラフルオロエチレン、ステアリン酸亜鉛などが、流動化剤としては、例えばポリメチルメタクリレート、ポリスチレン、シリコーン、疎水化処理されたあるいは疎水化処理されていないシリカ、アルミナ、チタニア、マグネシア、非晶質珪素−アルミニウム共酸化物、非晶質珪素−チタニウム共酸化物などの微粉末が、研磨剤としては、例えばチタン酸ストロンチウム、チタン酸カルシウム、炭酸カルシウム、酸化クロム、炭化珪素、タングステンカーバイドなどの微粉体が挙げられる。また、導電性付与剤として酸化スズの如き金属酸化物等を加えることもできる。しかし、これらは外添剤の一例を示したにすぎないものであり、本発明の静電荷像現像用トナーの外添剤が上記具体的に例示されたものに限定されるものではない。これら外添剤である滑剤、流動化剤、研磨剤などの使用量は、トナー１００重量部当り、滑剤は、０．１〜２重量部、流動化剤は、０．０５〜１重量部、研磨剤は、０．２〜５重量部が好ましい。また、これら外添剤はトナーに対し荷電制御性をも有することが多いので、トナーの荷電特性に応じ適宜のものを選択使用すればよい。
【００４３】
本発明のトナーは、キャリアと混合して二成分現像剤として用いることもできるし、トナー中に磁性粉を含有させた一成分現像剤或いはマイクロトーニング現像剤として用いることもできる。本発明のトナーが二成分現像剤として用いられる場合、キャリアとしては、従来公知のキャリアがいずれも使用できる。このようなキャリアとしては、例えば鉄粉等の強磁性金属あるいは強磁性金属の合金粉、酸化鉄などの金属酸化物、ニッケル、銅、亜鉛、マグネシウム、バリウム等の元素から構成されるフェライト粉、マグネタイト粉などの磁性粉からなる磁性粉キャリア、これら磁性粉をスチレン・メタクリレート共重合体、スチレン重合体、シリコーン樹脂等の樹脂で被覆した磁性粉樹脂コートキャリア、磁性粉とバインダー樹脂からなるバインダーキャリア、樹脂被覆されたあるいは樹脂被覆されていないガラスビーズなどが挙げられる。これらのキャリアは、通常２０〜２００μｍ、好ましくは３０〜１５０μｍ程度の粒径のものが用いられる。
【００４４】
なお、磁性粉樹脂コートキャリアの被覆樹脂としては、例えば、ポリエチレン、シリコーン樹脂、フッ素系樹脂、スチレン系樹脂、アクリル系樹脂、スチレン−アクリル系樹脂、ポリ酢酸ビニル、セルロース誘導体、マレイン酸樹脂、エポキシ樹脂、ポリ塩化ビニル、ポリ塩化ビニリデン、ポリ臭化ビニル、ポリ臭化ビニリデン、ポリカーボネート、ポリエステル、ポリプロピレン、フェノール樹脂、ポリビニルアルコール、フマル酸エステル樹脂、ポリアクリロニトリル、ポリビニルエーテル、クロロプレンゴム、アセタール樹脂、ケトン樹脂、キシレン樹脂、ブタジエンゴム、スチレン−ブタジエン共重合体、ポリウレタンなどが使用できる。これらのなかでは、スペントトナーの形成が少ないためフッ素含有樹脂、シリコーン含有樹脂が特に好ましい。
この磁性粉樹脂コートキャリアには、導電性微粒子（カーボンブラック、導電性金属酸化物、金属粉体）、無機充填材（シリカ、窒化ケイ素、窒化ホウ素、アルミナ、ジルコニア、炭化ケイ素、炭化ホウ素、酸化チタン、クレイ、タルク、ガラス繊維）、前記例示の荷電制御剤などを、必要に応じ含有させてもよい。キャリア芯材に対する樹脂被覆膜厚は、０．１〜５μｍ程度が好ましい。
【００４５】
【実施例】
以下、実施例により発明を更に具体的に説明する。しかし、以下の実施例は単に本発明を説明するためのものであり、本発明がこれら実施例に記載されたものに限定されるわけではない。
【００４６】
高分子化用ポリエステル樹脂（Ａ）の製造
製造例Ａ
１５リットルの四つ口フラスコに、還流冷却器、水分離装置、窒素ガス導入管、温度計及び攪拌装置を取り付け、ビスフェノールＡ・プロピレンオキサイド付加物（三井化学製ポリオールＫＢ３００）４０．６モル％、トリメチロールプロパン１０．２モル％、ステアリン酸４．８モル％、イソフタル酸４４．４モル％の量仕込み、フラスコ内に窒素を導入しながら、１８０〜２４０℃で脱水縮合を行った。反応生成物の酸価及び水酸基価が所定の値に達したところで反応生成物をフラスコより抜き出し、冷却、粉砕して、高分子化用ポリエステル樹脂Ａ１を得た。得られた高分子化用ポリエステル樹脂Ａ１の物性値を表１に示す。
【００４７】
製造例Ａ２〜Ａ４
原料に用いるカルボン酸化合物及びアルコール化合物の種類及び量（モル比）を表１のものとすることを除いて、製造例Ａ１に従い、高分子化用ポリエステル樹脂Ａ２〜Ａ４を製造した。得られた高分子化用ポリエステル樹脂の物性値を表１に示す。
【００４８】
【表１】

【００４９】
低分子ポリエステル樹脂（Ｂ）の製造
製造例Ｂ１〜Ｂ２
原料に用いるカルボン酸化合物及びアルコール化合物の種類及び量（モル比）を表２のものとすることを除いて、製造例Ａ１に従い、低分子ポリエステル樹脂Ｂ１〜Ｂ２を製造した。得られた低分子ポリエステル樹脂Ｂ１〜Ｂ２の物性値を表２に示す。
【００５０】
【表２】

【００５１】
使用した離型剤Ｗ１〜Ｗ４
使用した離型剤の特性値を表３に示す。
【００５２】
【表３】

【００５３】
離型剤含有ウレタン変性ポリエステル樹脂の製造
実施例１
高分子化用ポリエステル樹脂Ａ１及び低分子ポリエステル樹脂Ｂ１を、Ａ１が４０重量％、Ｂ１が６０重量％の割合で用い、かつ低分子ポリエステル樹脂Ｂ１をまず６ｋｇ／ｈｒの流量で二軸混練機（栗本鉄工所製、ＫＥＸ−４０）に供給し、これに高分子化用ポリエステル樹脂Ａ１を４ｋｇ／ｈｒの流量で供給して溶融混練搬送し、この混練搬送中の樹脂混合物に、更にトリレンジイソシアネートを３２０ｇ／ｈｒの流量で供給して（ＮＣＯ／ＯＨ当量比は０．８２に相当。ＮＣＯ／ＯＨ当量比）＝（供給トリレンジイソシアネートのＮＣＯ基当量／ｈｒ）／（供給樹脂のＯＨ基当量／ｈｒ）であり、（（３２０／１７６）ｘ２／（（５５．３ｘ４＋４．８ｘ６）／５６．１１）＝０．８１６）、更に離型剤Ｗ１を２００ｇ／ｈｒの流量で供給して混練を続けて反応を行い、押出後冷却することにより離型剤含有ウレタン変性ポリエステル樹脂Ｃ１を得た。この離型剤含有ウレタン変性ポリエステル樹脂Ｃ１の物性を表４に示す。
【００５４】
【表４】

【００５５】
実施例２〜５、参考例１、比較例１
表４に示す条件以外は実施例１に従い、離型剤含有ウレタン変性ポリエステル樹脂Ｃ２〜Ｃ７を得た。この離型剤含有ウレタン変性ポリエステル樹脂Ｃ２〜Ｃ７の物性値を表４に示す。
【００５６】
比較例２
離型剤を添加しないこと以外は実施例１と同様にして、離型剤を含有しないウレタン変性ポリエステル樹脂Ｃ８を得た。
【００５７】
離型剤含有ウレタン変性ポリエステル樹脂の評価
実施例６
離型剤含有ウレタン変性ポリエステル樹脂Ｃ１６０．５重量部磁性体（マグネタイト）３８．０重量部電荷調整剤（含金属系クロム染料；スピロンブラック１．５重量部ＴＲＨ、保土ヶ谷化学社製）をヘンシェルミキサーで混合した後、二軸加熱混練機に投入して混練し、押し出されてきたものを室温で冷却し、ハンマーミルで粗粉砕した後ターボミル粉砕機で微粉砕し、気流式風力分級機に導き平均粒径１１．０μｍ、６．４μｍ以下の粒径を有するものが１．０体積％以下、２０．０μｍ以上に粒径を有するものが１．０体積％以下の磁性トナー用微粉末を得た。このトナー用微粉末１００重量部に対し、疎水性シリカ（アエロジルＲ−９７４、日本アエロジル社製）を０．３重量部添加、混合して一成分磁性トナーを得た。この一成分磁性トナーの帯電性及び画出し評価を行い、表５の結果を得た。表５に示すように、本実施例のトナーは、帯電量及び画像濃度共に良好である。
【００５８】
【表５】

【００５９】
なお、各評価は次のように行われた。
（帯電量）一成分トナー１ｇとノンコートフェライトキャリア１９ｇを５０ｃｃのポリビンに入れ、３０分混合した後、ブローオフ粉体帯電量測定装置（東芝ケミカル社製）を用いトナーの帯電量を測定した。
【００６０】
（画出し試験）複写機としてキャノン社製ＮＰ−６６５０を用い、常温、常湿（２３℃、５０％）（Ｎ／Ｎ）において３０，０００枚の複写を行い、また高温、高湿（３０℃、８５％）（Ｈ／Ｈ）において３０，０００枚の複写を行い、各々１枚目及び３０，０００枚或いは３０，０００枚目の画像濃度及びかぶりを測定した。
【００６１】
（定着下限温度）試験機としてキャノン社製ＮＰ−６６５０を用いて定着を行い、低温オフセットが発生せず定着している下限の温度を、定着下限温度とした。
【００６２】
（オフセット発生温度）高温オフセットの発生した温度をオフセット発生温度とした。
【００６３】
（耐ブロッキング性）現像剤５０ｇを広口瓶に入れ、５０℃×２４時間放置し、放置後室温に戻し、現像剤中の大きな塊の有無を目視評価した。
〇・・・大きな塊なし。
□・・・大きな塊があるが、簡単にほぐれる。
×・・・簡単にほぐれない大きな塊がある。
【００６４】
（トナー中の離型剤平均分散粒径）トナーをエポキシ樹脂で包含して試料を固定した後、ミクロトームを用いて透過型電子顕微鏡観察用の試料を作製した。この時ミクロトームのナイフはダイアモンドナイフを用い、オスミウムを用いて離型剤部分の染色を行なった。得られた試料を透過型電子顕微鏡で観察し、トナー中に分散される離型剤の粒径を画像解析装置にて測定した。この時任意の１００個の分散している離型剤を抽出して粒径（最大長径）を求めその平均値を求め、平均粒径とした。
【００６５】
（巻き付き防止性）定着下限温度付近での紙の熱ロールへの巻き付きを観察して評価し、巻き付きが大きいものを×、巻き付きが少ないものを□、巻き付かないものを〇とした。
【００６６】
（トナー中の離型剤の分配性）トナー粉砕、分級工程において得られたトナー微粉末（分級品）及びそれより粒度の細かい分級微粉について、離型剤の含有量を求めて分配性の確認を行なった。離型剤含有量においてトナー微粉末と分級微粉との差がなければ分配性は良好であり、その差が大きいものは分配性が悪く、分級微粉を再度リサイクルすることが困難になってしまう。ここではＤＳＣ（示差走査熱量計）を用いて、既知の離型剤量含有トナーサンプル（０．１％、０．２％、０．３％）について離型剤の融点ピークの熱量を利用して検量線を作成し、定量分析を行ないサンプル中の離型剤の含有量を測定した。そして分級微粉中の離型剤量／トナー微粉末中の離型剤量の比を求め、その値が０．９より小さいものは分配不良を起こしていて、０．９以上は分配性が良好であるとした。
【００６７】
実施例７〜１０、参考例２
ウレタン変性ポリエステル樹脂Ｃ１に代えてウレタン変性ポリエステル樹脂Ｃ２〜Ｃ６を用いることを除き、実施例６に従い、一成分磁性トナーを得た。実施例６と同様にして、得られたトナーの評価を行い、表５の結果を得た。表５から明らかなように、実施例７〜１０及び参考例２のトナーはいずれも帯電量及び現像画像濃度、耐久性、環境安定性に優れていることが分かる。
【００６８】
比較例３
ウレタン変性ポリエステル樹脂Ｃ１に代えてウレタン変性ポリエステル樹脂Ｃ７を用いることを除き、実施例６に従い、一成分磁性トナーを得た。実施例６と同様にして、得られた現像剤の評価を行い、表５の結果を得た。表５から明らかなように、比較例３の現像剤は、実施例６〜１０のものに比べ画像濃度、かぶりともに劣っていた。またトナー中の離型剤の分配不良が見られた。
【００６９】
比較例４
ウレタン変性ポリエステル樹脂Ｃ８　５８．５重量部、磁性体（マグネタイト）３８．０重量部、電荷調整剤（含金属系クロム染料；スピロンブラックＴＲＨ、保土ヶ谷化学社製）１．５重量部、離型剤Ｗ１　２．０重量部をヘンシェルミキサーで混合した後、二軸加熱混練機に投入して混練し、押し出されてきたものを室温で冷却し、ハンマーミルで粗粉砕した後ターボミル粉砕機で微粉砕し、実施例６と同様に磁性トナー用微粉末を得、更に一成分磁性トナーを得た。この一成分磁性トナーの帯電性及び画出し評価を行い、表５の結果を得た。表５に示すように、本比較例のトナーは、画像濃度が低下し、かぶりも多かった。またトナー中の離型剤の分配不良が見られた。
【００７０】
比較例５
（成分）　　　　　　　　　　　　　　　　　　　　　　　（配合量）
ポリオキシプロピレン（２．２）−２，２−ビス（４−ヒドロキシフェニル）プロパン、ポリオキシエチレン（２．２）−２，２−ビス（４−ヒドロキシフェニル）プロパン、テレフタル酸、ドデセニル無水こはく酸、無水トリメリット酸を縮重合せしめて得られた非線状ポリエステル樹脂　　　　　　　　　　　５８．５重量部
磁性体（マグネタイト）　　　　　　　　　　　　　　　　　　　　　　　　　　　　　３８．０重量部
含金属系クロム染料
（スピロンブラックＴＲＨ、保土ヶ谷化学社製　）　　　　　　　１．５重量部
離型剤Ｗ１　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　２．０重量部
上記原材料をヘンシェルミキサーで混合した後、二軸加熱混練機に投入して混練し、押し出されてきたものを室温で冷却し、ハンマーミルで粗粉砕した後ターボミル粉砕機で微粉砕し、実施例６と同様に磁性トナー用微粉末を得、更に一成分磁性トナーを得た。この一成分磁性トナーの帯電性及び画出し評価を行い、表５の結果を得た。表５に示すように、本比較例のトナーは、かぶりが多く、トナー中の離型剤の分配不良が見られた。
【００７１】
比較例６
アイコサン二酸、パラターシャリーブチル安息香酸及びテレフタル酸からなる酸成分とロジングリシジルエステル、ポリオキシプロピレン（２．２）−２，２−ビス（４−ヒドロキシフェニル）プロパン、ポリオキシエチレン（２．２）−２，２−ビス（４−ヒドロキシフェニル）プロパンからなるアルコール成分と架橋成分としての無水トリメット酸を縮重合せしめて得られた非線状ポリエステル樹脂
５８．５重量部
磁性体（マグネタイト）　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　３８．０重量部
含金属系クロム染料
（スピロンブラックＴＲＨ、保土ヶ谷化学社製　）　　　　　　　　　　　　１．５重量部
離型剤Ｗ１　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　２．０重量部
上記原材料をヘンシェルミキサーで混合した後、二軸加熱混練機に投入して混練し、押し出されてきたものを室温で冷却し、ハンマーミルで粗粉砕した後ターボミル粉砕機で微粉砕し、実施例６と同様に磁性トナー用微粉末を得、更に一成分磁性トナーを得た。この一成分磁性トナーの帯電性及び画出し評価を行い、表５の結果を得た。表５に示すように、本比較例のトナーは、かぶりが多くまたトナー中の離型剤の分配不良が見られた。
【００７２】
実施例１１
（成分）　　　　　　　　　　　　　　　　　　　　　　　（配合量）
離型剤含有ウレタン変性ポリエステル樹脂　　　　　　　９０．５重量部
カーボンブラック　　　　　　　　　　　　　　　　　　　　　８重量部
含金属系クロム染料
（スピロンブラックＴＲＨ、保土ヶ谷化学社製　）　　　　　　　１．５重量部
上記材料をヘンシェルミキサーで均一に混合した後、二軸加熱混練機に投入し混練、押し出されてきたものを室温で冷却し、ハンマーミルで粗粉砕してチップを得た。次いで、これをターボミル粉砕機で微粉砕し、分級機に導き、１１．５μｍに平均粒度を有する部分を取り出して、トナー用微粉末を得た。次いで、このトナー用微粉末１００重量部に対し、疎水性シリカ微粉体０．３重量部を添加、混合して負帯電性黒トナーを得た。得られたトナー５部と平均粒径５０μｍのシリコーン樹脂コートのキャリア９５部とをボールミルを用いて混合し現像剤を作製した。次にこのトナーと現像剤を用いて、市販のフルカラー複写機キヤノン社製ＣＬＣ−５５０により、２３℃、５０％ＲＨの環境下で実写試験を行なった。得られたトナーおよび現像剤を用いたところ、３万枚実写後でもカブリは少なく、画像濃度も安定しており、機内のトナー飛散、画像汚れも見られなかった。初期および３万枚複写時の画像濃度は各々１．３８および１．３７であり、また初期および３万枚複写時のカブリは各々０．６および０．７であった。
【００７３】
なお、画像濃度はマクベス光度計を用いて行い、１．３５以上の濃度であればよい。なお、カブリはフォトボルトにて、反射率を測定することにより行った。１．２％以下が良好な値である。また、トナーの機内飛散は、複写機の転写チャージャー上に飛散トナーが存在するか否かを確認することにより行った。転写チャージャー上にトナー飛散がみられる場合、これに伴い画像汚れが発生する。
【００７４】
実施例１２
（成分）　　　　　　　　　　　　　　　　　　　　　　　（配合量）
離型剤含有ウレタン変性ポリエステル樹脂　　　　　　　　　９３．５重量部
フタロシアニン顔料（Ｃ．Ｉ．ＰＩＧＭＥＮＴ　ＢＬＵＥ　１５：３）　　　　　　　　　　　５重量部
３，５−ジ−ｔｅｒｔ−ブチルサリチル酸の３価クロム塩　　　１．５重量部
上記材料をヘンシェルミキサーで均一に混合した後、二軸加熱混練機に投入し混練、押し出されてきたものを室温で冷却し、ハンマーミルで粗粉砕してチップを得た。次いで、これをターボミル粉砕機で微粉砕し、分級機に導き、１１．５μｍに平均粒度を有する部分を取り出して、トナー用微粉末を得た。次いで、このトナー用微粉末１００重量部に対し、疎水性シリカ微粉体０．３重量部を添加、混合して負帯電性シアントナーを得た。得られたトナー５部と平均粒径５０μｍのシリコーン樹脂コートのキャリア９５部とをボールミルを用いて混合し現像剤を作製した。次にこのトナーと現像剤を用いて、市販のフルカラー複写機キヤノン社製ＣＬＣ−５５０により、２３℃、５０％ＲＨの環境下で実写試験を行なった。得られたトナーおよび現像剤を用いたところ、３万枚実写後でもカブリは少なく、画像濃度も安定しており、機内のトナー飛散、画像汚れも見られなかった。初期および３万枚複写時の画像濃度は各々１．４０および１．３９であり、また初期および３万枚複写時のカブリは各々０．６および０．７であった。
【００７５】
【発明の効果】
上述したように、本発明においては、特定の酸価、水酸基価、分子量を有する高分子化用ポリエステル樹脂（Ａ）及び低分子ポリエステル樹脂（Ｂ）を多価イソシアネート化合物と反応させて得られた低酸価のウレタン変性ポリエステル樹脂（Ｃ）を静電荷像現像用トナーに含有せしめることにより、低酸価のポリエステル樹脂を用いるにもかかわらず帯電性に優れたトナーを製造することができ、またポリエステル樹脂が低酸価であるため耐湿性にすぐれ、高温、高湿時にも良好な現像画像を形成することができ、しかも低温定着性、耐オフセット性、耐ブロッキング性の何れもが良好で、巻きつき防止性や離型剤の分散性の優れた静電荷像現像用トナーを得ることができ、どのような複写環境においても長期間安定した現像を行うことができるという優れた効果を有する。[0001]
[Industrial applications]
The present invention relates to a toner, a developer and a release agent-containing urethane-modified polyester resin used for developing an electrostatic image in electrophotography, electrostatic printing, and the like. The present invention relates to a toner for electrostatic image development, a developer, and a release agent-containing urethane-modified polyester resin used in the toner, which has both good properties and anti-offset properties, and also has excellent anti-winding properties and release agent dispersibility.
[0002]
[Prior art]
With the development of office automation, the demand for copying machines and laser printers using electrophotography has been rapidly increasing, and the demand for their performance has also become more sophisticated. In general, in order to obtain a visible image using electrophotography, a photosensitive member such as selenium, amorphous silicon, or an organic semiconductor is charged, exposed, developed using a developer containing a toner, and developed on a photosensitive member. A method has been adopted in which the formed toner image is transferred onto transfer paper and then fixed using a heat roll or the like. At this time, it is needless to say that the developed image has no fog and a clear image having a sufficient image density needs to be formed. From a viewpoint, it is strongly demanded that a fixing process can be performed at a lower temperature, and a toner having an excellent low-temperature fixing property is also demanded. In order to improve the fixability of the toner, it is generally necessary to reduce the viscosity of the toner at the time of melting to increase the adhesion area with the fixing base material. Therefore, the glass transition point (Tg) of the binder resin of the conventionally used toner is required. ) Or reducing the molecular weight. However, resins having a low glass transition point generally have poor blocking resistance, so that it is difficult to stably exist as a powder when using or storing the toner, and when a toner image is fixed by a hot roll fixing method. Has the disadvantage that the toner in the molten state comes into direct contact with the hot roll at the time of fixing, but the toner transferred onto the hot roll at this time stains the next transfer paper or the like, that is, the so-called offset phenomenon easily occurs. . This tendency becomes more pronounced when the molecular weight of the resin is smaller.
[0003]
In recent years, a digital system capable of outputting information from a computer or a facsimile has been spotlighted as an image forming system in the electrophotographic system. In the digital exposure, a laser is used as an exposure means, so that a fine line drawing can be output as compared with the conventional analog method, and a toner having a small particle size is required to obtain a more delicate image. However, when the particle size of the toner is reduced, if the dispersibility of the release agent is poor, the release agent falls off and the rate of recovery as fine powder increases. Generally, fine powder generated in the pulverizing step is collected and recycled as a raw material. If the fine powder has a large release agent content, it becomes difficult to recycle the fine powder, which is not preferable. In addition, the release agent falls off the toner surface during stirring with the carrier in the copying machine, which causes unstable charging amount and causes filming on the photoreceptor. In order to solve these problems, it is desirable that the release agent is finely and uniformly dispersed in the toner, but since the release agent is generally made of low molecular weight polypropylene or polyethylene, it is generally used for polyester and the like. In many cases, the dispersibility of the release agent tends to be large.
[0004]
Further, from the viewpoint of chargeability and fixability, various toners using a polyester resin as a binder resin instead of a styrene acrylic resin or an epoxy resin have been proposed (for example, Japanese Patent Application Laid-Open No. 61-284773, JP-A-62-291668, JP-B-7-101318, JP-B-8-3663, U.S. Pat. No. 4,833,057, etc.). However, the polyester resin has a higher surface tension than a styrene acrylic resin generally used as a binder resin for a toner, and thus has a problem that the paper is easily wound around a hot roll. In addition, when a polyester resin is used as the binder resin, the negative chargeability of the toner generally increases in proportion to the concentration of the terminal carboxyl group. , The amount of charge of the toner is reduced, and the quality of a developed image is reduced. Further, the copier is required to be maintenance-free, including the handling of the toner, and there is a high demand for a toner capable of obtaining a stable developed image for a long period of time.
[0005]
[Problems to be solved by the invention]
The present invention aims to provide a toner for developing an electrostatic image, a developer and a urethane-modified polyester resin containing a release agent for a toner, which does not have these conventional problems and satisfies the above-mentioned various characteristics that have been conventionally required for the toner. It was done. That is, an object of the present invention is to provide a release agent which has good chargeability, image density, low-temperature fixability, anti-offset properties, and anti-blocking properties, and has good anti-winding properties and good dispersibility of release agents. It is an object of the present invention to provide a stable and high-density developed image even at high temperature and high humidity or at low temperature and low humidity. To provide a toner and a developer for developing an electrostatic charge image. It is another object of the present invention to provide a toner and a developer for developing an electrostatic image capable of forming a stable developed image for a long period of time. Still another object of the present invention is to provide a urethane-modified polyester resin containing a release agent used for a toner for developing an electrostatic image and a developer.
[0006]
[Means for Solving the Problems]
The present inventors have conducted intensive studies in order to solve these problems, and as a result, when a specific polyester resin is used as a raw material and this is reacted with a polyvalent isocyanate, the specific polyester resin is formed by adding a specific release agent. It has been found that the above object can be achieved by using a specific release agent-containing urethane-modified polyester resin for a toner for developing an electrostatic image, thereby completing the present invention. That is, the present invention relates to the following inventions (1) to (5).
(1) at least polymerizing a polyester resin (A) and a low molecular polyester resin (B) when allowed to mixing the polyvalent isocyanate compound reaction, the number average molecular weight that will be determined by gel permeation chromatography (GPC) (Mn) is from 800 to 2,000, and is obtained by adding an ethylene homopolymer having a value of weight average molecular weight / number average molecular weight (Mw / Mn) of 1.5 or less as a release agent. Urethane-modified polyester resin containing a release agent for toner.
(2) The release agent-containing urethane for a toner according to (1), wherein the total acid value of the polyester resin for polymerization (A) and the low molecular weight polyester resin (B) is 5 to 20 KOHmg / g. Modified polyester resin.
(3) The release agent-containing urethane-modified polyester for toner according to (1) or (2), wherein the average dispersion particle diameter of the release agent in the urethane-modified polyester resin is 1 μm or less. resin.
(4) A toner for developing an electrostatic image, comprising at least a urethane-modified polyester resin containing a release agent for a toner according to any one of (1) to (3) and a coloring agent.
(5) A two-component electrophotographic developer comprising the electrostatic image developing toner described in (4) and a carrier.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in more detail. As described above, the urethane-modified polyester resin containing a release agent for a toner of the present invention uses the polyester resin for polymerization (A), the low-molecular polyester resin (B), the polyvalent isocyanate compound, and the release agent as raw materials. Things.
[0008]
With respect to the polyester resin (A) for polymerization, at least one diol, at least one dicarboxylic acid, and at least one trivalent or more trivalent or more monomer in an amount of 0.5 to 20 mol% based on all raw material monomers. It is preferably produced by polycondensation using at least a polyhydric alcohol, and at the time of polycondensation, at least one long-chain aliphatic monocarboxylic acid or a long-chain aliphatic monocarboxylic acid in an amount of 2 to 20 mol% based on all the starting monomers. More preferably, a chain aliphatic monoalcohol is further present. Moreover, it is preferable that a hydroxyl value is 40-70 KOHmg / g.
[0009]
As the diol used for producing the polyester resin for polymerization (A), any of diols conventionally used for producing a polyester resin can be used. 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2,3-butanediol, diethylene glycol, triethylene glycol, dipropylene glycol, 1,5-pentanediol Bisphenols such as 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenyl A, bisphenyl A / ethylene oxide adduct, bisphenyl A / propylene oxide adduct Derivatives Bisphenyl A. ethylene oxide adducts and bisphenyl A. propylene oxide adducts are preferably those represented by the following general formula.
[0010]
Embedded image

[0011]
On the other hand, as the dicarboxylic acid, any of those conventionally used in producing a polyester resin can be used. Preferred examples thereof include malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, and azelaic acid. Alkyldicarboxylic acids such as acids, maleic acid, fumaric acid, citraconic acid, unsaturated dicarboxylic acids such as itaconic acid, phthalic acid, terephthalic acid, isophthalic acid, benzenedicarboxylic acids such as phthalic anhydride, anhydrides of these dicarboxylic acids or Lower alkyl esters and the like can be mentioned. Examples of the trihydric or higher polyhydric alcohol component include glycerin, 2-methylpropanetriol, trimethylolpropane, trimethylolethane, sorbit, and sorbitan. When the trihydric or higher polyhydric alcohol component is usually less than 0.5 mol% based on the total amount of the raw material monomers, it is difficult to polymerize, and the offset resistance tends to be insufficient. If it exceeds 20 mol%, gelation is likely to occur and polycondensation is difficult to occur, so it is preferably used in an amount of 0.5 to 20 mol%, more preferably 2 to 20 mol%.
[0012]
Examples of long-chain aliphatic monocarboxylic acids include aliphatic monocarboxylic acids having 8 to 22 carbon atoms, such as octanoic acid, decanoic acid, dodecanoic acid, myristic acid, palmitic acid, and stearic acid. It may have a saturated group. Further, examples of the long-chain aliphatic monoalcohol include aliphatic monoalcohols having 8 to 22 carbon atoms such as octanol, decanol, dodecanol, myristyl alcohol, palmityl alcohol, and stearyl alcohol. The amount of the long-chain aliphatic monocarboxylic acid or long-chain aliphatic monoalcohol to be used is preferably 2 to 20 mol% based on the total amount of the raw material monomers, and if it is less than 2 mol%, the anti-winding property and the release agent dispersion are reduced. The effect is small, and if the amount exceeds 20 mol%, the monofunctional compound inhibits polymerization and becomes difficult to polymerize, which is not preferable. Since long-chain aliphatics have a property of lowering the glass transition point, aromatic monocarboxylic acids such as benzoic acid and naphthalene carboxylic acid may be used for adjusting the glass transition point. If necessary, a trivalent or higher polycarboxylic acid can be used, and a trivalent or higher polycarboxylic acid is not excluded as a raw material of the polyester resin (A) for polymerization. .
[0013]
On the other hand, as the low-molecular polyester resin (B), any resin can be used regardless of the production method or the synthesis raw material, but the hydroxyl value is 10 KOHmg / g or less and the weight average molecular weight is 3, It is preferably from 000 to 5,000. Here, if the weight average molecular weight of the low molecular weight polyester resin (B) is less than 3,000, there is a problem in the offset property of the formed toner, which is not preferable. From the viewpoint of fixability, the weight average molecular weight is more preferably 5,000 or less. Preferred examples of the low-molecular polyester resin (B) include a linear polyester resin produced using at least one diol and at least one dicarboxylic acid, and if necessary, at least one monocarboxylic acid. . Preferred compounds as the diol and dicarboxylic acid used in the production of the low-molecular polyester resin (B) include the same compounds as those mentioned as the raw materials for producing the polyester resin for polymerization (A). it can. Further, as the monocarboxylic acid, octanoic acid, decanoic acid, dodecanoic acid, myristylic acid, palmitic acid, aliphatic monocarboxylic acids having 8 to 22 carbon atoms such as stearic acid, aromatic monocarboxylic acids such as benzoic acid, etc. And benzoic acid is particularly preferred.
[0014]
The polycondensation reaction for obtaining the above-mentioned polyester resin for polymerization (A) and low-molecular polyester resin (B) includes, for example, high-temperature polycondensation in the presence of a solvent without using a solvent such as nitrogen gas, solution polycondensation and the like. Can be performed by a known method. The ratio of carboxylic acid (dicarboxylic acid, monocarboxylic acid, etc.) and alcohol (monoalcohol, diol, trifunctional alcohol, etc.) used in the reaction is 0.7 to 1.4, which is the ratio of the former carboxyl group to the latter hydroxyl group. It is common that
[0015]
In the urethane-modified polyester resin containing a release agent for a toner of the present invention, the polyester resin for polymerization (A) and the low-molecular polyester resin (B) are reacted with a polyvalent isocyanate compound, and at that time, a release agent is added. However, when the amount of the low molecular weight polyester resin (B) increases, the offset property of the toner tends to deteriorate when used as a binder resin for a toner for developing an electrostatic image. When the amount of the polyester resin (A) increases, the low-temperature fixability of the toner tends to deteriorate. For this reason, the mixing ratio of the high molecular weight polyester resin (A) and the low molecular weight polyester resin (B) is a weight ratio, and the high molecular weight polyester resin (A): the low molecular weight polyester resin (B) is 3 to 5: Most preferred is 7 to 5.
When the total acid value of the high molecular weight polyester resin (A) and the low molecular weight polyester resin (B) exceeds 20 KOHmg / g, the resulting toner containing the release agent-containing urethane-modified polyester resin is charged. In some cases, it is difficult to form a developed image having a low density and a sufficient density even under high temperature and high humidity. When the total acid value is less than 5 KOHmg / g, the dispersion particle size of the release agent becomes large, and it may be difficult to uniformly disperse the release agent.
[0016]
On the other hand, examples of the polyvalent isocyanate compound include diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and tetramethylene diisocyanate, and isocyanates represented by the following (1) to (5). Can be mentioned.
[0017]
Embedded image

[0018]
The amount of the polyvalent isocyanate to be used is generally 0.2 to 1.2 equivalents, preferably 0.3 to 1.0 equivalent, as isocyanate groups per 1 equivalent of hydroxyl groups of all polyester resins.
[0019]
The release agent that can be preferably used in the present invention is a completely saturated ethylene homopolymer.
As for the molecular weight of the ethylene homopolymer, the number average molecular weight (Mn) is preferably from 800 to 2,000. If the number average molecular weight (Mn) is less than 800, the composition is susceptible to thermal effects excessively, and may have poor developability such as blocking resistance and reduced image density. Is larger than 2,000, heat from the outside cannot be used effectively, and it may be difficult to obtain excellent fixing properties and offset resistance.
Further, Mw / Mn, which is a ratio between the weight average molecular weight (Mw) and the number average molecular weight (Mn), is preferably 1.5 or less, more preferably 1.3 or less. Mw / Mn represents the degree of dispersion of the molecular weight distribution. The smaller the numerical value is, the smaller the molecular weight distribution is, the more uniform the molecule is, the better the compatibility is, and the more preferable it is for dispersing the release agent in the resin well. .
Accordingly, the polyethylene homopolymer having the characteristics of the present invention has excellent compatibility even when mixed with a urethane polyester resin, and can obtain a good dispersion state. As a result, a good average dispersed particle size of the release agent in the urethane-modified polyester resin of 1.0 μm or less can be obtained.
[0020]
The particle size of the release agent of the present invention is preferably 100 μm or less. If it is larger than 100 μm, it becomes difficult to disperse and distribute the wax in a polyester resin, which increases the particle diameter of the dispersed wax, which hinders the quality of the toner.
[0021]
The amount of the release agent added is preferably 0.5 to 10 parts by weight based on 100 parts by weight of the urethane-modified polyester resin. More preferably, it is 1 to 6 parts by weight. If the amount is less than 1 part by weight, the effect of adding the release agent cannot be obtained, while if it exceeds 10 parts by weight, a problem may occur in compatibility with the urethane-modified polyester resin. When the release agent becomes excessive, the release agent is unevenly distributed in the toner, and the release agent is released when the toner is finely pulverized, and the released release agent is used to film the photoconductor, the developing sleeve, and the carrier. Such a problem may occur.
[0022]
These reactions are carried out by mixing the polyester resin for polymerization (A), the low-molecular polyester resin (B) and the polyvalent isocyanate compound, further adding a release agent, and melt-mixing. A method in which a melt of the polyester resin for polymerization (A) and a melt of the low molecular weight polyester resin (B) are kneaded, a polyvalent isocyanate compound and a release agent are added to the kneaded material, and melt kneading is preferred. . As a specific method for performing the melt mixing, a mixture of the polyester resin for polymerization (A) and the low molecular weight polyester resin (B) is injected into a twin-screw extruder at a constant speed, and simultaneously with the polyisocyanate. A mold agent is also injected at a constant speed, or a low-molecular polyester resin (B), a polyester resin for polymerization (A), a polyvalent isocyanate and a release agent are sequentially injected in the feed direction of the twin-screw extruder, A method of performing reaction and mixing while kneading and conveying at a temperature of 100 to 200 ° C. can be employed. At this time, the low-molecular-weight polyester resin (B) and the polyester resin for polymerization (A), which are the reaction raw materials charged or injected into the twin-screw extruder, are directly extruded without cooling from the polyester resin reaction vessel. The injection may be carried out into an extruder, or the produced resin may be cooled, crushed or beaded and supplied to a twin-screw extruder. However, in the present invention, the method for producing the release agent-containing urethane-modified polyester resin is not limited to the methods specifically exemplified above. Needless to say, it can be performed by an appropriate method such as a method of heating to a certain temperature and mixing. The release agent-containing urethane-modified polyester resin used in the present invention preferably has a gel content of 0.1 to 25%. For this gel portion, 5 g of the resin was mixed with 100 ml of ethyl acetate for 4 hours, and then allowed to stand for one day and night. Thereafter, the supernatant was gently collected with a dropper, and the amount of the dissolved polymer obtained was measured by the nonvolatile content. It is obtained.
[0023]
In the present invention, the molecular weight distribution of the binder resin, the release agent component and the like is measured by GPC under the following conditions.
[0024]
Equipment: GPC-150C (Waters)
Column: GMH-HT 30 cm 2 stations (Tosoh Corporation)
Temperature: 135 ° C
Solvent: o-dichlorobenzene (0.1% ionol added)
Flow rate: 1.0 ml / min
Sample: Inject 0.4 ml of a 0.15% sample.
The measurement is performed under the above conditions, and the molecular weight of the sample is calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample. Further, it is calculated by converting into polyethylene using a conversion formula derived from the Mark-Houwink viscosity formula.
[0026]
In the present invention, the acid value refers to the number of mg of potassium hydroxide required to neutralize 1 g of the resin, and the hydroxyl value refers to a reaction between a hydroxyl group of the resin and phthalic anhydride. It means the number of mg of potassium hydroxide required to neutralize the required acid per 1 g of the resin.
[0027]
Regarding the measurement of the dispersed particle size of the release agent in the urethane-modified polyester resin, a sample was prepared according to the following procedure, and the dispersed particle size was determined using a transmission electron microscope. After a urethane-modified polyester resin containing a release agent was covered with a resin having high strength against electron beams, for example, an epoxy resin, and the sample was fixed, a sample for transmission electron microscope observation was prepared using a microtome. At this time, a diamond knife was used as a microtome knife. The release agent was stained with osmium. The obtained sample was observed with a transmission electron microscope, and the particle size of the release agent dispersed in the urethane-modified polyester resin was measured. At this time, as a method of measuring the particle size, not only the measurement using a photograph but also an image analyzer may be used. In the present invention, an arbitrary 100 dispersed release agents are extracted, the particle size (maximum major axis) is determined, and the average value is determined to be the average particle size.
[0028]
The dispersed particle size of the release agent in the urethane-modified polyester resin is preferably 1 μm or less. More preferably, it is 0.8 μm or less. If the dispersion particle size of the release agent is 1 μm or less, the excellent release agent can be dispersed in the toner, and good quality can be obtained. If it is 1 μm or less, it can be uniformly dispersed in the urethane-modified polyester, and can maintain good dispersibility and distribution even when it is formed into a toner.
On the other hand, if it is larger than 1 μm, it becomes difficult to disperse the release agent well in the urethane-modified polyester resin, and it becomes difficult to distribute the release agent uniformly to individual toner particles. When poor distribution occurs, particularly the classified fine powder having a small particle diameter has a large release agent content, and a single release agent is present.
In this way, when the dispersion and the distribution failure of the release agent occur, a good image such as an increase in fog cannot be obtained, or the classified fine powder cannot be recycled at the time of toner production due to a bias in the compounding amount due to the distribution failure. This leads to problems such as an increase in cost.
[0029]
In the toner for developing an electrostatic image of the present invention, in addition to the release agent-containing urethane-modified polyester resin, if necessary, other known binder resins, charge control agents, coloring agents, and other release agents And materials commonly used in the production of toner such as external additives.
[0030]
As the other binder resin that can be used together with the release agent-containing urethane-modified polyester resin, any binder resin that is conventionally known as a binder resin for a toner for developing an electrostatic image may be used. For example, polystyrene, poly-p- Homopolymers of styrene such as chlorostyrene and polyvinyltoluene and their substituted products; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylate copolymer Copolymer, styrene-methacrylic ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene- Vinyl methyl ketone copolymer Styrene copolymers such as styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer; polyvinyl chloride, phenolic resin, natural modified phenolic resin, natural resin modified maleic acid resin, Acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin other than the urethane-modified polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, cumarone indene resin, petroleum Resins such as resins and cross-linked styrene copolymers are exemplified.
[0031]
As the colorant used in the present invention, any of dyes and pigments conventionally used as colorants for toner particles can be used, and the following black, yellow, magenta, and cyan colorants are used. It is preferably used. In the case of a magnetic toner, a magnetic powder is also used as a coloring agent.
[0032]
As the black colorant, carbon black, aniline black, acetylene black, iron black and the like are preferably used. Carbon black that can be used in the present invention can be broadly classified into two types: furnace black and channel black. The electrical properties and triboelectricity of the toner are affected by the type and the amount added. These colorants can be used alone or as a mixture of two or more kinds, and are usually 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight based on 100 parts by weight of the binder resin. Is good.
[0033]
In the case of a magnetic powder used for a magnetic toner, a compound of iron oxide or a divalent metal and iron oxide such as magnetite, maghemite, and ferrite; a metal such as iron, cobalt, and nickel; or aluminum, cobalt, and copper of these metals And powders of alloys of metals such as lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof. These magnetic materials preferably have an average particle diameter of 0.05 to 2.0 μm, preferably about 0.1 to 0.5 μm, and are contained in the magnetic toner in an amount of 100 parts by weight of the binder resin. It is 5 to 150 parts by weight, preferably 10 to 120 parts by weight. If necessary, a magnetic material and a coloring agent can be used in combination. As the coloring agent, for example, carbon black, copper phthalocyanine, iron black and the like are used.
[0034]
As the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complex compounds, methine compounds and allylamide compounds are used. 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. These colorants can be used alone or in admixture of two or more, and usually 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight, per 100 parts by weight of the binder resin. Good addition amount.
[0035]
As the magenta coloring agent, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 254, etc. are preferably used. These colorants can be used alone or in admixture of two or more, and usually 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight, per 100 parts by weight of the binder resin. Good addition amount.
[0036]
As the cyan coloring agent, a copper phthalocyanine compound and its derivative, an anthraquinone compound, a basic dye lake compound and the like can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 and the like are suitably used. These colorants can be used alone or in admixture of two or more, and usually 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight, per 100 parts by weight of the binder resin. Good addition amount.
[0037]
Further, as a method of dispersing the colorant in the binder resin, a resin chip containing a high concentration of the colorant in advance by a flash method is manufactured, and this is mixed with the binder resin. Either method can be adopted.
[0038]
Further, a charge control agent can be used for the purpose of stably controlling the charge amount in the toner. As the charge control agent, any of those conventionally known as charge control agents for toners for developing electrostatic images can be used. As the charge control agent, a positive charge control agent or a negative charge control agent is selected depending on the polarity of the electrostatic charge image on the electrostatic latent image carrier to be developed.As the positive charge control agent, for example, Nigrosine dye, fatty acid metal derivative, triphenylmethane dye, quaternary ammonium salt (for example, tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylbenzylammonium tetrafluoroborate), diorganotin oxide (for example, , Dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide), diorganotinborate (dibutyltinborate, dioctyltinborate, dicyclohexyltinborate) and the like, and these can be used alone or in combination of two or more. Of these, nigrosine-based, quaternary ammonium salts and triphenylmethane-based dyes are preferred. On the other hand, examples of the negative charge control agent include compounds having a carboxyl group, for example, a metal salt or a metal chelate (complex) of salicylic acid or a salicylic acid derivative, a metal complex dye, a fatty acid soap, a metal salt of naphthenic acid, and the like. These charge control agents are used in a proportion of usually 0.1 to 8 parts by weight, preferably 0.5 to 6 parts by weight, based on 100 parts by weight of the binder resin.
[0039]
The method for preparing the toner for developing an electrostatic image of the present invention is not particularly limited, and can be appropriately prepared by a conventionally known method. As an example of the toner adjusting method, the above-mentioned toner components are preliminarily mixed by a dry blender, a Henschel mixer, a ball mill, and the like, and then, the mixture is hot-kneaded by a hot roll kneader, a uniaxial or biaxial extruder, or the like. After melt kneading with a mill, the obtained kneaded material is cooled, then mechanically coarsely pulverized using a pulverizer such as a hammer mill, and then finely pulverized with a jet pulverizer or the like, and then classified to a desired particle size if necessary. A preferred method is a method of producing by the method described above.
[0040]
The toner of the present invention preferably has a weight average particle diameter of 3 to 15 μm. In particular, 12 to 60% by number of toner particles having a particle diameter of 5 μm or less, 1 to 33% by number of toner particles having a particle diameter of 8 to 12.7 μm, and toner particles having a particle diameter of 16 μm or more Is 2.0% by weight or less, and the weight average particle diameter of the toner is more preferably 4 to 10 μm from the viewpoint of developing characteristics. The particle size distribution of the toner can be measured using, for example, a Coulter counter.
[0041]
When the developer of the present invention is an insulating magnetic toner, it preferably has an electrical resistance of 10 ¹⁰ Ω · cm or more, preferably 10 ¹³ Ω · cm or more. The toner for developing an electrostatic charge image thus prepared is mixed with an external additive as needed.
[0042]
The toner of the present invention may further contain, if necessary, known additives used in the production of toner, such as a releasing agent, a lubricant, a fluidizing agent, an abrasive, a conductivity-imparting agent, and an image peeling inhibitor. It can be used as an agent.
Specifically, as the lubricant, for example, polytetrafluoroethylene, zinc stearate and the like, as the fluidizing agent, for example, polymethyl methacrylate, polystyrene, silicone, silica that has been hydrophobized or not hydrophobized, Fine powders of alumina, titania, magnesia, amorphous silicon-aluminum co-oxide, amorphous silicon-titanium co-oxide and the like are used as abrasives, for example, strontium titanate, calcium titanate, calcium carbonate, chromium oxide , Silicon carbide, and fine powder of tungsten carbide. Further, a metal oxide such as tin oxide can be added as a conductivity imparting agent. However, these are merely examples of the external additives, and the external additives of the electrostatic image developing toner of the present invention are not limited to those specifically exemplified above. The amounts of these external additives such as lubricants, fluidizers and abrasives are 0.1 to 2 parts by weight of lubricant, 0.05 to 1 part by weight of fluidizer per 100 parts by weight of toner, The amount of the abrasive is preferably 0.2 to 5 parts by weight. In addition, since these external additives often have charge controllability with respect to the toner, an appropriate additive may be selected and used according to the charge characteristics of the toner.
[0043]
The toner of the present invention can be used as a two-component developer by mixing with a carrier, or can be used as a one-component developer or a microtoning developer in which magnetic powder is contained in the toner. When the toner of the present invention is used as a two-component developer, any conventionally known carrier can be used as the carrier. Such carriers include, for example, ferromagnetic metals or alloy powders of ferromagnetic metals such as iron powder, metal oxides such as iron oxide, ferrite powder composed of elements such as nickel, copper, zinc, magnesium, and barium; Magnetic powder carrier composed of magnetic powder such as magnetite powder, magnetic powder resin coated carrier obtained by coating these magnetic powders with resin such as styrene / methacrylate copolymer, styrene polymer, silicone resin, etc., binder carrier composed of magnetic powder and binder resin And resin-coated or non-resin-coated glass beads. These carriers generally have a particle size of about 20 to 200 μm, preferably about 30 to 150 μm.
[0044]
As the coating resin of the magnetic powder resin-coated carrier, for example, polyethylene, silicone resin, fluorine resin, styrene resin, acrylic resin, styrene-acryl resin, polyvinyl acetate, cellulose derivative, maleic acid resin, epoxy resin Resin, polyvinyl chloride, polyvinylidene chloride, polyvinyl bromide, polyvinylidene bromide, polycarbonate, polyester, polypropylene, phenolic resin, polyvinyl alcohol, fumaric ester resin, polyacrylonitrile, polyvinyl ether, chloroprene rubber, acetal resin, ketone Resin, xylene resin, butadiene rubber, styrene-butadiene copolymer, polyurethane and the like can be used. Among these, a fluorine-containing resin and a silicone-containing resin are particularly preferable because the formation of spent toner is small.
The magnetic powder resin-coated carrier includes conductive fine particles (carbon black, conductive metal oxide, metal powder), inorganic fillers (silica, silicon nitride, boron nitride, alumina, zirconia, silicon carbide, boron carbide, oxide Titanium, clay, talc, glass fiber), the charge control agent exemplified above, and the like may be contained as necessary. The thickness of the resin coating on the carrier core material is preferably about 0.1 to 5 μm.
[0045]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples. However, the following examples are merely for describing the present invention, and the present invention is not limited to those described in the examples.
[0046]
Production of polyester resin for polymerization (A) Production example A
A 15-liter four-necked flask was equipped with a reflux condenser, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer. 40.6 mol% of a bisphenol A / propylene oxide adduct (Mitsui Chemicals polyol KB300) was added. Trimethylolpropane 10.2 mol%, stearic acid 4.8 mol%, and isophthalic acid 44.4 mol% were charged, and dehydration condensation was performed at 180 to 240 ° C while introducing nitrogen into the flask. When the acid value and the hydroxyl value of the reaction product reached predetermined values, the reaction product was extracted from the flask, cooled and pulverized to obtain a polyester resin A1 for polymerization. Table 1 shows the physical property values of the obtained polyester resin A1 for polymerization.
[0047]
Production Examples A2 to A4
Except that the types and amounts (molar ratios) of the carboxylic acid compound and alcohol compound used as the raw materials were as shown in Table 1, polyester resins A2 to A4 for polymerization were produced according to Production Example A1. Table 1 shows the physical property values of the obtained polyester resin for polymerization.
[0048]
[Table 1]

[0049]
Production of low molecular polyester resin (B) Production Examples B1 and B2
Low-molecular-weight polyester resins B1 to B2 were produced in accordance with Production Example A1, except that the types and amounts (molar ratios) of the carboxylic acid compound and the alcohol compound used as the raw materials were as shown in Table 2. Table 2 shows the physical property values of the obtained low-molecular polyester resins B1 and B2.
[0050]
[Table 2]

[0051]
Release agents W1 to W4 used
Table 3 shows the characteristic values of the release agents used.
[0052]
[Table 3]

[0053]
Production of release agent-containing urethane-modified polyester resin Example 1
A high molecular weight polyester resin A1 and a low molecular weight polyester resin B1 are used at a ratio of 40% by weight of A1 and 60% by weight of B1. KEX-40, manufactured by Kurimoto Tekkosho Co., Ltd., and the polyester resin A1 for polymerization is supplied at a flow rate of 4 kg / hr, melt-kneaded and conveyed, and the resin mixture being kneaded and conveyed is further treated with tolylene diisocyanate. Is supplied at a flow rate of 320 g / hr (NCO / OH equivalent ratio is equivalent to 0.82. NCO / OH equivalent ratio) = (NCO group equivalent of tolylene diisocyanate / hr) / (OH group equivalent of supply resin) / (Hr), ((320/176) × 2 / ((55.3 × 4 + 4.8 × 6) /56.11) = 0.816), and the release agent W1 at a flow rate of 200 g / hr. The reaction was conducted continuously Kneading sheet to obtain a release agent containing urethane-modified polyester resin C1 by cooling after extrusion. Table 4 shows the physical properties of the release agent-containing urethane-modified polyester resin C1.
[0054]
[Table 4]

[0055]
Examples 2 to 5, Reference Example 1, Comparative Example 1
In accordance with Example 1 except for the conditions shown in Table 4, release agent-containing urethane-modified polyester resins C2 to C7 were obtained. Table 4 shows the physical property values of the release agent-containing urethane-modified polyester resins C2 to C7.
[0056]
Comparative Example 2
A urethane-modified polyester resin C8 containing no release agent was obtained in the same manner as in Example 1 except that no release agent was added.
[0057]
Evaluation of release agent-containing urethane-modified polyester resin Example 6
160.5 parts by weight of a release agent-containing urethane-modified polyester resin C 38.0 parts by weight of a magnetic substance (magnetite) 38.0 parts by weight of a charge controlling agent (metal-containing chromium dye; 1.5 parts by weight of spiron black TRH, manufactured by Hodogaya Chemical Co., Ltd.) After mixing with a mixer, it is put into a twin-screw kneader and kneaded. A powder having a lead average particle diameter of 11.0 μm and a particle diameter of 6.4 μm or less is 1.0 vol% or less, and a powder having a particle diameter of 20.0 μm or more is 1.0 vol% or less. Obtained. 0.3 parts by weight of hydrophobic silica (Aerosil R-974, manufactured by Nippon Aerosil Co., Ltd.) was added to and mixed with 100 parts by weight of this toner fine powder to obtain a one-component magnetic toner. The one-component magnetic toner was evaluated for chargeability and image appearance, and the results shown in Table 5 were obtained. As shown in Table 5, the toner of this example has good charge amount and image density.
[0058]
[Table 5]

[0059]
In addition, each evaluation was performed as follows.
(Charge amount) 1 g of the one-component toner and 19 g of the non-coated ferrite carrier were placed in a 50 cc polybin and mixed for 30 minutes, and then the charge amount of the toner was measured using a blow-off powder charge amount measuring device (manufactured by Toshiba Chemical Corporation).
[0060]
(Image output test) Using NP-6650 manufactured by Canon Inc. as a copying machine, 30,000 sheets were copied at normal temperature and normal humidity (23 ° C., 50%) (N / N). (30 ° C., 85%) (H / H), 30,000 copies were made, and the image density and fog of the first copy and 30,000 copies or 30,000 copies were measured, respectively.
[0061]
(Fixing lower limit temperature) Fixing was performed using NP-6650 manufactured by Canon Inc. as a tester, and the lower limit temperature at which fixing was performed without causing low-temperature offset was defined as the fixing lower limit temperature.
[0062]
(Offset occurrence temperature) The temperature at which the high-temperature offset occurred was taken as the offset occurrence temperature.
[0063]
(Blocking resistance) 50 g of the developer was placed in a jar, left at 50 ° C. for 24 hours, returned to room temperature, and visually evaluated for the presence or absence of large lumps in the developer.
〇: No large lump.
□ ・ ・ ・ There is a large lump, but it can be loosened easily.
×: There are large chunks that cannot be easily unraveled.
[0064]
(Average Dispersion Particle Size of Release Agent in Toner) The sample was fixed by enclosing the toner with an epoxy resin, and a sample for transmission electron microscope observation was prepared using a microtome. At this time, the knife of the microtome was dyed using a diamond knife, and the release agent portion was dyed using osmium. The obtained sample was observed with a transmission electron microscope, and the particle size of the release agent dispersed in the toner was measured with an image analyzer. At this time, an arbitrary 100 dispersed release agents were extracted, the particle size (maximum major axis) was determined, and the average value was determined to be the average particle size.
[0065]
(Anti-winding property) Evaluation was made by observing the winding of the paper around the heat roll near the lower limit temperature of fixing.
[0066]
(Distribution property of release agent in toner) For toner fine powder (classified product) obtained in the toner pulverization and classification process and classified fine powder having a finer particle size than the above, the content of the release agent was determined and distribution was confirmed. Was performed. If there is no difference between the toner fine powder and the classified fine powder in the content of the release agent, the distribution is good, and if the difference is large, the distribution is poor, and it becomes difficult to recycle the classified fine powder again. Here, using a DSC (Differential Scanning Calorimeter), the calorific value of the melting point peak of the release agent is used for the known release agent amount-containing toner samples (0.1%, 0.2%, 0.3%). Then, a calibration curve was prepared, quantitative analysis was performed, and the content of the release agent in the sample was measured. Then, the ratio of the amount of the release agent in the classified fine powder / the amount of the release agent in the toner fine powder is determined. If the ratio is smaller than 0.9, poor distribution is caused. It was assumed to be.
[0067]
Examples 7 to 10, Reference Example 2
A one-component magnetic toner was obtained according to Example 6, except that the urethane-modified polyester resins C2 to C6 were used instead of the urethane-modified polyester resin C1. The obtained toner was evaluated in the same manner as in Example 6, and the results shown in Table 5 were obtained. As is clear from Table 5, the toners of Examples 7 to 10 and Reference Example 2 are all excellent in charge amount, developed image density, durability, and environmental stability.
[0068]
Comparative Example 3
A one-component magnetic toner was obtained according to Example 6, except that the urethane-modified polyester resin C7 was used instead of the urethane-modified polyester resin C1. The obtained developer was evaluated in the same manner as in Example 6, and the results shown in Table 5 were obtained. As is clear from Table 5, the developer of Comparative Example 3 was inferior in both image density and fog as compared with those of Examples 6 to 10. In addition, poor distribution of the release agent in the toner was observed.
[0069]
Comparative Example 4
58.5 parts by weight of a urethane-modified polyester resin C8, 38.0 parts by weight of a magnetic substance (magnetite), 1.5 parts by weight of a charge control agent (metal-containing chromium dye; Spiron Black TRH, manufactured by Hodogaya Chemical Co., Ltd.), release After mixing 2.0 parts by weight of the agent W1 with a Henschel mixer, the mixture was put into a twin-screw kneader and kneaded. The extruded product was cooled at room temperature, coarsely pulverized by a hammer mill, and then finely pulverized by a turbo mill pulverizer. By pulverizing, a fine powder for magnetic toner was obtained in the same manner as in Example 6, and a one-component magnetic toner was obtained. The one-component magnetic toner was evaluated for chargeability and image appearance, and the results shown in Table 5 were obtained. As shown in Table 5, the toner of this comparative example had lower image density and more fog. In addition, poor distribution of the release agent in the toner was observed.
[0070]
Comparative Example 5
(Components) (Blending amount)
Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, terephthalic acid, dodecenyl anhydride amber Non-linear polyester resin obtained by condensation polymerization of acid and trimellitic anhydride 58.5 parts by weight Magnetic substance (magnetite) 38.0 parts by weight Metal-containing chromium dye (Spiron Black TRH, Hodogaya Chemical Co., Ltd.) 1.5 parts by weight Release agent W1 2.0 parts by weight After mixing the above-mentioned raw materials with a Henschel mixer, the mixture is put into a twin-screw kneader and kneaded, and the extruded material is cooled at room temperature, and is then hammer milled. After coarse pulverization, fine pulverization is performed using a turbo mill pulverizer. Obtained to give an additional one-component magnetic toner. The one-component magnetic toner was evaluated for chargeability and image appearance, and the results shown in Table 5 were obtained. As shown in Table 5, the toner of this comparative example had much fog and poor distribution of the release agent in the toner was observed.
[0071]
Comparative Example 6
Acid components consisting of eicosane diacid, paratertiary butyl benzoic acid and terephthalic acid, rosin glycidyl ester, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2. 2) 58.5 parts by weight of a non-linear polyester resin obtained by condensation polymerization of an alcohol component composed of -2,2-bis (4-hydroxyphenyl) propane and trimetic anhydride as a crosslinking component (magnetite) 38.0 parts by weight Metal-containing chromium dye (Spiron Black TRH, Hodogaya Chemical Co., Ltd.) 1.5 parts by weight Release agent W1 2.0 parts by weight After mixing the above raw materials with a Henschel mixer, a biaxial heating kneader. What has been extruded Was cooled at room temperature, coarsely pulverized by a hammer mill, and then finely pulverized by a turbo mill to obtain a fine powder for a magnetic toner in the same manner as in Example 6, and further to obtain a one-component magnetic toner. The one-component magnetic toner was evaluated for chargeability and image appearance, and the results shown in Table 5 were obtained. As shown in Table 5, the toner of the present comparative example exhibited high fog and poor distribution of the release agent in the toner.
[0072]
Example 11
(Components) (Blending amount)
Release agent-containing urethane-modified polyester resin 90.5 parts by weight Carbon black 8 parts by weight Metal-containing chromium dye (Spiron Black TRH, manufactured by Hodogaya Chemical Co., Ltd.) 1.5 parts by weight After uniformly mixing the above materials with a Henschel mixer The mixture was put into a twin-screw kneader, kneaded and extruded, cooled at room temperature, and roughly ground with a hammer mill to obtain chips. Next, this was finely pulverized by a turbo mill and led to a classifier to take out a portion having an average particle size of 11.5 μm to obtain a fine powder for toner. Next, 0.3 parts by weight of hydrophobic silica fine powder was added to and mixed with 100 parts by weight of the toner fine powder to obtain a negatively chargeable black toner. 5 parts of the obtained toner and 95 parts of a silicone resin-coated carrier having an average particle diameter of 50 μm were mixed using a ball mill to prepare a developer. Next, using the toner and the developer, an actual photographing test was conducted with a commercially available full-color copying machine CLC-550 manufactured by Canon Inc. at 23 ° C. and 50% RH. When the obtained toner and developer were used, fog was small, image density was stable even after 30,000 copies were actually taken, and toner scattering and image contamination in the apparatus were not observed. The image densities at the initial and 30,000 copies were 1.38 and 1.37, respectively, and the fog at the initial and 30,000 copies were 0.6 and 0.7, respectively.
[0073]
The image density is measured using a Macbeth photometer and may be a density of 1.35 or more. The fog was measured by measuring the reflectance with a photobolt. A good value is 1.2% or less. The scattering of the toner inside the apparatus was performed by checking whether or not the scattering toner was present on the transfer charger of the copying machine. When toner is scattered on the transfer charger, an image stain is generated accordingly.
[0074]
Example 12
(Components) (Blending amount)
Release agent-containing urethane-modified polyester resin 93.5 parts by weight Phthalocyanine pigment (CI. PIGMENT BLUE 15: 3) 5 parts by weight Trivalent chromium salt of 3,5-di-tert-butylsalicylic acid 1.5 parts by weight After the materials were uniformly mixed with a Henschel mixer, the mixture was charged into a twin-screw kneader, kneaded and extruded, cooled at room temperature, and roughly pulverized with a hammer mill to obtain chips. Next, this was finely pulverized by a turbo mill and led to a classifier to take out a portion having an average particle size of 11.5 μm to obtain a fine powder for toner. Next, 0.3 parts by weight of hydrophobic silica fine powder was added to and mixed with 100 parts by weight of this toner fine powder to obtain a negatively chargeable cyan toner. 5 parts of the obtained toner and 95 parts of a silicone resin-coated carrier having an average particle diameter of 50 μm were mixed using a ball mill to prepare a developer. Next, using the toner and the developer, an actual photographing test was conducted with a commercially available full-color copying machine CLC-550 manufactured by Canon Inc. at 23 ° C. and 50% RH. When the obtained toner and developer were used, fog was small, image density was stable even after 30,000 copies were actually taken, and toner scattering and image contamination in the apparatus were not observed. The image densities at the initial and 30,000 copies were 1.40 and 1.39, respectively, and the fog at the initial and 30,000 copies were 0.6 and 0.7, respectively.
[0075]
【The invention's effect】
As described above, in the present invention, a polyester resin (A) for polymerization having a specific acid value, a hydroxyl value, and a molecular weight and a low molecular weight polyester resin (B) are obtained by reacting with a polyvalent isocyanate compound. By incorporating the urethane-modified polyester resin (C) having a low acid value into the toner for developing an electrostatic image, it is possible to produce a toner having excellent chargeability despite using a polyester resin having a low acid value. Since the polyester resin has a low acid value, it has excellent moisture resistance, and can form a good developed image even at high temperature and high humidity. It is possible to obtain a toner for developing an electrostatic charge image having excellent anti-winding properties and dispersibility of a release agent, and stable development can be performed for a long time in any copying environment. Has an excellent effect that kill.

Claims (5)

When mixing and reacting at least the polyester resin for polymerization (A), the low-molecular polyester resin (B) and the polyvalent isocyanate compound, the number average molecular weight (Mn) measured by gel permeation chromatography (GPC) Is from 800 to 2,000, and obtained by adding an ethylene homopolymer having a value of weight average molecular weight / number average molecular weight (Mw / Mn) of 1.5 or less as a releasing agent. Urethane-modified polyester resin containing a release agent. The urethane-modified polyester resin containing a release agent for a toner according to claim 1, wherein the total acid value of the polyester resin for polymerization (A) and the low-molecular polyester resin (B) is 5 to 20 KOHmg / g. . 3. The urethane-modified polyester resin containing a release agent for a toner according to claim 1, wherein an average dispersion particle diameter of the release agent in the urethane-modified polyester resin is 1 μm or less. 4. A toner for developing an electrostatic image, comprising at least the urethane-modified polyester resin containing a release agent for a toner according to any one of claims 1 to 3 and a colorant. A two-component electrophotographic developer comprising the electrostatic image developing toner according to claim 4 and a carrier.