JP2004219507A - Electrostatic image developing toner and developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic image developing toner excellent in productivity, hot storage property, fixing property, transparency and environmental stability, and ensuring little occurrence of fog and ghost phenomenon, and to provide a developing device. <P>SOLUTION: In the electrostatic image developing toner 62 containing at least a binder resin, a colorant, a release agent and a charge controlling agent, a polyolefin resin having a cyclic structure is contained as the binder resin, is characterized in that the release agent comprises a polypropylene wax or a polyethylene wax, and the charge controlling agent is a specified organic boron compound. Internal addition of the polypropylene wax or polyethylene wax improves transparency and fixability, and the specified organic boron compound suppresses the occurrence of fog and ghost phenomenon and assures stable electrostatic charge of the toner and stable development, thereby, the toner using the cyclic polyolefin resin free of environmental problem can be put into practical use. The wax is added in an amount of 1-10.0 mass%, preferably about 2.0-4.0 mass%. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００１８】
本発明の静電像現像用トナーにおいて、上記離型剤の含有量が１．０〜１０質量％であることが望ましい。上記含有量が１．０質量％未満では、低温オフセット傾向や、透明性で難点があり、１０質量％を超えると、熱保存性の悪化やトナーの凝集に基く白筋の発生等を生じることがあり好ましくない。
【００１９】
また、本発明の静電像現像用トナーにおいて、上記離型剤の示差走査熱量測定における吸収熱量ピーク温度が８０℃〜１４０℃の範囲にあることが非オフセット領域を広げる上で好ましい。
【００２０】
上記課題を解決するため、本発明の現像装置では、静電像担持体に対向すべく開口部を有し静電像現像用トナーを収容するトナーホッパと、上記静電像担持体に圧接すべく上記開口部に一部が臨むごとく設けられ、上記トナーを表面に保持して上記静電像担持体上の静電像を現像すべく搬送する弾性現像ローラと、上記開口部よりも上記弾性現像ローラの搬送方向上流側で上記トナーを上記弾性現像ローラ上に薄層状に形成すべく規制するドクターブレードと、上記トナーホッパ内に配設され上記ドクターブレードよりも上記弾性現像ローラの搬送方向上流側で上記弾性現像ローラに圧接する供給ローラと、上記開口部よりも上記弾性現像ローラの搬送方向下流側で上記弾性現像ローラに軽圧接し上記トナーホッパ内に上記トナーが戻るのを許容すると同時に上記トナーホッパ内からのトナーの流出を規制する導電性規制シート部材と、少なくとも上記弾性現像ローラと上記供給ローラにバイアス電圧を印加するバイアス電圧印加手段とを備え、上記トナーが、結着樹脂、着色剤、離型剤、荷電制御剤を少なくとも含有してなり、上記結着樹脂として環状構造を持ったポリオレフィン樹脂を含み、上記離型剤がポリプロピレンワックスもしくはポリエチレンワックスからなり、上記荷電制御剤が下記式（Ｉ）で示される有機ホウ素化合物であることを特徴とする現像装置を提供する。
【化４】

【００２１】
本発明の現像装置において、上記離型剤の含有量が１．０〜１０質量％であることが望ましく、また、上記離型剤の示差走査熱量測定における吸収熱量ピーク温度が８０℃〜１４０℃の範囲にあることが好ましい。
このような本発明の現像装置によれば、定着オフセットが無く、透明性に優れ、カブリ、ゴースト現象の発生の無い画像形成が可能となる。
【００２２】
本発明の静電像現像用トナーは、次のような一般的な製造方法により製造することができる。
まず、結着樹脂、着色剤、荷電制御剤、ワックス、等をヘンシェルミキサ等により均一に混合する。次いで、この混合物を、ニーダー、エクストルーダー、ロールミル等を用い、溶融混練する。
【００２３】
次に、混練物をハンマーミル、カッターミル等を用いて粗粉砕した後、ジェトミル、１式ミル等で微粉砕する。その後、微粉砕物をＤＳ（分散式分級機）、ジクザグ分級機等により分級する。分級により得るトナーの平均粒径としては、３〜１８μｍが好適である。
【００２４】
この分級されたトナー粒子に対し、必要に応じてシリカ等の流動性向上剤を添加してヘンシェルミキサ等により均一に混合し、トナーが製造される。シリカは、シリコーンオイル等を用いて、表面が疎水化処理されたものであってもよい。
【００２５】
【発明の実施の形態】
以下、本発明の実施の形態を示し、本発明をより具体的に説明する。
図１に、本発明のトナーおよび現像装置が組み込まれたカラー画像形成装置（プリンタ装置）の内部構成を模式的に示す。先ず、同図を用いて本発明に係わるカラー画像形成装置の全体構成について説明する。
【００２６】
同図のプリンタ装置１の内部構成は、画像形成部２、両面印刷用搬送ユニット３、および給紙部４等で構成されている。ここで、画像形成部２は、４個の画像形成ユニット５〜８を並設した構成であり、同図の紙面右側から左側に向かってマゼンタ（Ｍ）、シアン（Ｃ）、イエロー（Ｙ）、ブラック（Ｋ）の順に配設されている。ここで、マゼンタ（Ｍ）、シアン（Ｃ）、イエロー（Ｙ）の画像形成ユニット５〜７は、減法混色によりカラー印刷を行う構成であり、ブラック（Ｋ）の画像形成ユニット８は、モノクロ印刷用であり、単独でも使用できる構成となっている。
【００２７】
上記各画像形成ユニット５〜８は、それぞれドラムユニットＤＵとトナーユニット（現像装置）ＴＵで構成され、トナーユニットＴＵのトナーホッパに収容されたトナーを除いて同じ構成である。画像形成ユニット５〜８のトナーユニットＴＵには、Ｍ（マゼンタ）、Ｃ（シアン）、Ｙ（イエロー）、ブラック（Ｋ）の各色トナー（非磁性一成分トナー）がそれぞれ収容されている。各色トナーはいずれも、本発明の定着安定性、透明性等に優れたトナーである。
【００２８】
そこで、本発明の現像装置を含む画像形成ユニット８を例にして、構成を説明する。ドラムユニットＤＵには、感光体ドラム９、帯電器１０ａ、クリーナ１０ｅ等が収容され、また、ドラムユニットＤＵの上方には印字ヘッド１０ｂが配置されている。トナーユニットＴＵは、現像装置４４内に現像ローラ１０ｃや本発明のトナーが収容され構成される。
【００２９】
感光体ドラム９は、その周面が例えば有機光導電性材料で構成され、感光体ドラム９の周面近傍には、帯電器１０ａ、印字ヘッド１０ｂ、現像ローラ１０ｃ、転写器１０ｄ、クリーナ１０ｅが順次配設されている。感光体ドラム９は、矢印方向に回動し、まず、帯電器１０ａからの電荷付与により、感光体ドラム９の周面に一様に帯電する。そして、印字ヘッド１０ｂからの印字情報に基づく光書き込みにより、感光体ドラム９の周面に静電潜像を形成し、現像ローラ１０ｃによる現像処理によりトナー像を形成する。このようにして、感光体ドラム９の周面に形成されるトナー像は、感光体ドラム９の矢印方向の回動に伴って転写器１０ｄの位置に達し、感光体ドラム９の真下を矢印方向に移動する用紙に転写される。
【００３０】
一方、用紙の搬送は、前述の給紙部４を構成する給紙カセット１１、待機ローラ対１２、搬送ベルト１３、駆動ローラ１４等で構成され、給紙コロ１１ａの回動により、給紙カセット１１から搬出された用紙は、待機ローラ対１２まで送られ、更に、トナー像に一致するタイミングで搬送ベルト１３上に送られ、各転写器１０ｄに達する。そして、各転写器１０ｄにおいてトナー像が転写され、トナー像が転写された用紙は搬送ベルト１３の移動に従って、搬送ベルト１３上を矢印方向に移動し、定着ユニット１５において熱定着処理が施される。
【００３１】
尚、上述の用紙は給紙カセット１１から搬出される用紙のみならず、ＭＰＦトレー１６から供給される用紙も含まれ、この場合には、用紙は給紙コロ１６ａによって搬入され、前述の経路によって印刷処理が行われる。
【００３２】
また、上記定着ユニット１５は、熱ローラ１５ａ、プレスローラ１５ｂおよびオイル塗布ローラ１５ｃ等で構成され、用紙が上述の熱ローラ１５ａとプレスローラ１５ｂの間を挟持搬送される間、用紙に転写された例えば複数色のトナー像は溶融して用紙に熱定着する。また、オイル塗布ローラ１５ｃは、熱ローラ１５ａ周面に離型性オイルを塗布すると共に熱ローラ１５ａに残るトナーを除去する機能を有する。
【００３３】
定着ユニット１５によってトナー像が定着された用紙は切換フラップ１７を介して上方、又は、紙面左方向に搬送される。切換フラップ１７は、通常、破線位置にあり、用紙は排紙ローラ対２０を介して排紙部２１へ案内される。
【００３４】
一方、両面印刷用搬送ユニット３は、装置本体に対して着脱自在に構成され、本例のプリンタ装置１によって両面印刷を行う際、装着するユニットであり、内部に複数の逆搬送ローラ対１８ａ〜１８ｅが配設されている。両面印刷の場合には、上記切換フラップ１７によって一旦上方に用紙が送られ、例えば用紙の後端が搬送ローラ対１９に達したとき、用紙の搬送を停止し、更に用紙を逆方向に搬送する。この制御によって、用紙は下方位置の両面印刷用搬送ユニット３の用紙搬送路に搬入され、逆搬送ローラ対１８ａ〜１８ｅによって用紙が逆方向に送られ、再度待機ローラ対１２に達し、前述したように、トナー像と一致するタイミングで転写部に送られ、トナー像が用紙の裏面に転写される。
【００３５】
図２に図１のプリンタ装置１の外観斜視図を示す。同図のプリンタ装置１は、装置本体上部２２と装置本体下部２３によって構成され、装置本体上部２２には、操作パネル３３が配設され、また、その上面には印字用紙の排出部２１も形成されている。操作パネル３３は、複数のキーが配設されたキー操作部３３ａと、後述する図３のＣＰＵ３０から出力される表示情報に基づき表示を行う液晶ディスプレイ等の表示部３３ｂとで構成されている。また、排紙部２１には、排紙ローラ対２０の回動によって、各画像形成部にて作成された印刷用紙が出力され、排紙部２１上に順次積載される。
【００３６】
また、装置本体下部２３には、その前面に開閉可能なフロントカバー２４が設けられている。このフロントカバー２４は例えばジャム処理やメンテナンス時に開放される。
【００３７】
図３は、上記構成のプリンタ装置１における回路ブロック図である。図３において、回路ブロックは、インターフェイスコントローラ（以下Ｉ／Ｆコントローラという）２６、プリンタコントローラ２８、プリンタ印字部２９、ＣＰＵ３０、ＲＯＭ３１、操作パネル３３、ＥＥＰＲＯＭ３２で構成されている。Ｉ／Ｆコントローラ２６は、ホスト機器から供給される印字データをビットマップデータに変換し、フレームメモリ２７に展開する。フレームメモリ２７は、マゼンタ（Ｍ）、シアン（Ｃ）、イエロー（Ｙ）、ブラック（Ｋ）ごとに記憶エリアが設定され、対応するエリアに各色のデータが展開される。
【００３８】
フレームメモリ２７に展開されたデータはプリンタコントローラ２８に出力され、ＣＰＵ３０の制御に従ってプリンタ印字部２９に出力される。このとき、マゼンタ（Ｍ）、シアン（Ｃ）、イエロー（Ｙ）、ブラック（Ｋ）の各色のデータは、それぞれ対応する図１の印字ヘッド１０ｂに供給される。
【００３９】
尚、ＲＯＭ３１には、本例のシステムプログラムが記憶され、ＣＰＵ３０は、このシステムプログラムに従って処理を行う。
【００４０】
次に、以上説明したプリンタ装置１の基本的な動作について説明する。まず、電源が投入され、使用する用紙の紙質、枚数、印字モード、その他の指定がキー入力あるいは接続するホスト機器からの信号として入力されると、不図示の駆動機構により給紙コロ１１ａが一回転して、給紙カセット１１に載置収容されている用紙を待機ローラ対１２方向へ給送する。待機ローラ対１２は、回転を一時停止して、一対のローラで形成される挟持部に用紙先端を当接させた状態で、搬送タイミングを待機する。
【００４１】
続いて、駆動ローラ１４が反時計回り方向に回転し、従動ローラ１４´が従動して、同じく反時計回り方向に回転する。これにより、搬送ベルト１３は、上循環部が４個の感光体ドラム９に当接して、全体が反時計回り方向へ循環移動する。
【００４２】
これと共に、各ドラムユニットＤＵとトナーユニットＴＵが印字タイミングに合わせて順次駆動される。感光体ドラム９は時計回り方向に回転し、帯電器１０ａは、感光体ドラム９周面に一様な高マイナス電荷を付与し、印字ヘッド１０ｂは、その感光体ドラム９周面に画像信号に応じて露光を行って、低電位部を形成する。これにより、上記帯電器１０ａによる高マイナス電位部と、露光による低マイナス電位部からなる静電潜像が形成される。現像装置４４の現像ローラ１０ｃは、その静電潜像の低電位部にトナーを転移させて、感光体ドラム９周面上にトナー像を形成（反転現像）する。
【００４３】
最上流の感光体ドラム９の周面上のトナー像の先端が、搬送ベルト１３との対向点に回転搬送されてくるタイミングで、その対向点に用紙の印字開始位置が一致するように、待機ローラ対１２が回転を開始して、用紙を用紙搬入部へ給送する。用紙は、搬送ベルト１３に吸着され、感光体ドラム９と転写器１０ｄにより形成されている最初の転写部へ搬送される。
【００４４】
転写器１０ｄは、転写バイアス電源から出力される転写電流を搬送ベルト１３を介して用紙に印加する。この転写器から印加される転写電流により、感光体ドラム９上のＭ（マゼンタ）のトナー像が用紙に転写される。続いて、上流から２番目の転写部においてＣ（シアン）のトナー像が転写され、更に上流から３番目の転写部においてＹ（イエロー）のトナー像が転写される。そして、上流から４番目（すなわち、最下流）の転写部においてＫ（ブラック）のトナー像が順次転写される。
【００４５】
このようにして、４色のトナー像を転写された用紙は、搬送ベルト１３から分離して定着ユニット１５に搬入される。定着ユニット１５は、トナー像を用紙に熱定着させる。この画像定着後、用紙は、例えば排紙ローラ対２０によって上部の排紙部２１上にトナー像を下にして排出される。
【００４６】
本発明に係わるプリンタ装置１は、４つの画像形成部が作動されてフルカラー画像を形成するためのフルカラーモードと、１つの画像形成部のみ作動されるモノクロモードを備えている。尚、上記Ｍ（マゼンタ）、Ｃ（シアン）、Ｙ（イエロー）の３つの画像形成部を作動させてフルカラーモードを構成することもできる。
【００４７】
以上のように動作するプリンタ装置１において、本発明による上記各現像装置４４は、感光体ドラム９上に安定したトナー像を形成するために、以下のような構成とされている。
【００４８】
図４は、本発明の現像装置４４の主要部を模式的に示す側断面図である。同図に示す現像装置４４は、プリンタ装置１に着脱自在であり、ドラムユニットＤＵと共に１つの画像形成ユニット８を構成するトナーユニットＴＵとされている。現像装置４４は、トナーホッパ６１を備え、そのトナーホッパ６１の下部開口に導電性ゴムローラからなる現像ローラ１０ｃを回転可能に保持し、トナーホッパ６１の内部には、トナー６２を収容し、このトナー６２に埋没するように配設されトナーを攪拌する攪拌部材６３を備えている。
【００４９】
また、現像装置４４の最下部には、スポンジ体から成る供給ローラ６４が現像ローラ１０ｃに圧接して配置されている。現像ローラ１０ｃには、その斜め右上周面に圧接して金属製の板バネ状のドクターブレード６５が配設され、下部周面に当接してスクイシート（導電性規制シート）６６が配設されている。このスクイシート６６には、バイアス電源７１を含む導電性規制シートバイアス手段が設けられている。ドクターブレード６５の両側部には、トナーホッパ６１開口部の内部と外部を隔絶してトナー６２の漏出を防止するための封止部材６７が配設されている。
【００５０】
ところで、感光体ドラム９への現像を終った後の現像ローラ１０ｃ周面上に残留する非現像部分のトナー６２を、現像メモリの解消のために現像装置内で掻き落とすために必要とされる供給ローラ６４の摺擦力は、トナー６２の現像ローラ１０ｃへの付着力によって異なる。すなわち、付着力の強いトナーに対しては強い摺擦力を必要とするが、付着力の弱いトナーに対しては弱い摺擦力で間に合う。トナー６２の現像ローラ１０ｃへの付着力は、略トナー６２の帯電能力によって決定されるといってよい。すなわち、摩擦帯電量の小さいものほど付着力が弱く、従って現像ローラ１０ｃから掻き落とし易い。
【００５１】
しかしながら、トナー６２の摩擦帯電量は、現像時に生じて不具合となる非画像部分への付着現像（所謂感光体カブリ）と密接な関係を有しており、帯電量の少ないトナーほど感光体カブリを発生させ易い。従って、このような感光体カブリを生じさせないためには、トナー６２の摩擦帯電量を高くする必要がある。そして、トナー６２の摩擦帯電量を高くすると現像ローラ１０ｃへの付着力が増すから、供給ローラ６４に強い摺擦力を与える必要が生じてくる。
【００５２】
このような強い摺擦力で長時間の回転を繰り返すと、トナーの帯電能力の低下や流動性の低下等現像特性の劣化を引き起こすので好ましくない。例えば、帯電量が低下すると、上述した感光体カブリが発生し、流動性が低下すると網点印刷の現像欠落が発生する。
【００５３】
そこで、本発明の現像装置４４においては、本発明の静電像現像用トナーを用いると共に、先ず、現像ローラ１０ｃを、芯金とこの芯金を取り巻く円筒状の半導電性（１０^６ Ωｃｍ）のウレタンゴムとで形成し、芯金には「略−２５０Ｖ」の現像バイアスをバイアス電源６８から印加する。また、供給ローラ６４を、芯金とこの芯金を取り巻く円筒状の半導電性（１０^６ Ωｃｍ）のウレタンスポンジとで構成し、芯金には「略−５００Ｖ」の供給バイアスをバイアス電源６９から印加する。
【００５４】
更に、ドクターブレード６５を弾性金属板で形成し、このドクターブレード６５にも上記バイアス電源６９から「略−５００Ｖ」のドクターバイアスを印加する。そして、供給ローラ６４の上流側に位置するスクイシート６６を導電性部材（１０^３ Ωｃｍ）で構成して、これに０Ｖ（０ボルト）から現像ローラ１０ｃの現像バイアス電圧までの範囲のシートバイアス電圧をバイアス電源７１により印加するようにしている。
【００５５】
スクイシート６６を導電性部材で構成して、これに０Ｖから現像ローラ１０ｃの現像バイアス電圧までの範囲のシートバイアス電圧を印加すると現像ローラ１０ｃ上に付着するトナー６２の電荷を減少させることができる。これにより、供給ローラ６４による弱い摺擦力によっても、容易に現像ローラ１０ｃ上に付着して戻ってきた非現像部分のトナーを掻き取ることができる。
【００５６】
このように、本発明の現像装置４４は、弾性ゴムからなる現像ローラ１０ｃを感光体ドラム９の表面に圧接させる接触現像（ローラ）方式を採用している。そして、上記のような装置構成により非磁性一成分トナー方式による高速且つ高品質の現像が得られている。
【００５７】
以上説明した現像装置、および以下の方法により製造された本発明トナーを用いて、定着性、透明性等に優れた画質の画像形成を行うことが出来る。
【００５８】
【実施例】
以下、本発明の静電像現像用トナーを製造する実施例を示し、本発明トナーについてより具体的に説明する。
【００５９】
＜実施例１＞
結着樹脂Ａ（ティコナ社製環状ポリオレフィン樹脂「ＴＭ」：Ｍｗ＝６，５００、Ｍｗ／Ｍｎ＝２）７２質量％、結着樹脂Ｂ（ティコナ社製環状ポリオレフィン樹脂「ＴＢ−１５」、Ｍｗ＝１４０，０００、Ｍｗ／Ｍｎ＝２８）２１質量％、着色剤（Ｃ．Ｉピグメントレッド５７：１）５質量％、離型剤（三井化学社製ポリプロピレンワックス「ＮＰ０５６」）１質量％、荷電制御剤（日本カーリット社製有機ホウ素化合物「ＬＲ−１４７」）１質量％をヘンシェルミキサ（三井鉱山社製）にて混合し、二軸連続混練機により溶融混練した。その後、冷却し、衝突板式粉砕機にて粉砕分級して、質量平均粒径約９μｍの着色微粒子を得た。次いで、この着色微粒子１００質量部、疎水性シリカ（日本アエロジル社製シリカ「Ｒ９７２」）１質量部を、ヘンシェルミキサで混合し、マゼンタ色トナーを得た。
【００６０】
＜実施例２＞
結着樹脂Ａ（ティコナ社製環状ポリオレフィン樹脂「ＴＭ」：Ｍｗ＝６，５００、Ｍｗ／Ｍｎ＝２）７１質量％、結着樹脂Ｂ（ティコナ社製環状ポリオレフィン樹脂「ＴＢ−１５」、Ｍｗ＝１４０，０００、Ｍｗ／Ｍｎ＝２８）２１質量％、着色剤（Ｃ．Ｉピグメントレッド５７：１）５質量％、離型剤（三井化学社製ポリプロピレンワックス「ＮＰ０５６」）２質量％、荷電制御剤（日本カーリット社製有機ホウ素化合物「ＬＲ−１４７」）１質量％をヘンシェルミキサ（三井鉱山社製）にて混合し、二軸連続混練機により溶融混練した。その後、冷却し、衝突板式粉砕機にて粉砕分級して、質量平均粒径約９μｍの着色微粒子を得た。次いで、この着色微粒子１００質量部、疎水性シリカ（日本アエロジル社製シリカ「Ｒ９７２」）１質量部を、ヘンシェルミキサで混合し、マゼンタ色トナーを得た。
【００６１】
＜実施例３＞
結着樹脂Ａ（ティコナ社製環状ポリオレフィン樹脂「ＴＭ」：Ｍｗ＝６，５００、Ｍｗ／Ｍｎ＝２）６９質量％、結着樹脂Ｂ（ティコナ社製環状ポリオレフィン樹脂「ＴＢ−１５」、Ｍｗ＝１４０，０００、Ｍｗ／Ｍｎ＝２８）２１質量％、着色剤（Ｃ．Ｉピグメントレッド５７：１）５質量％、離型剤（三井化学社製ポリプロピレンワックス「ＮＰ０５６」）４質量％、荷電制御剤（日本カーリット社製有機ホウ素化合物「ＬＲ−１４７」）１質量％をヘンシェルミキサ（三井鉱山社製）にて混合し、二軸連続混練機により溶融混練した。その後、冷却し、衝突板式粉砕機にて粉砕分級して、質量平均粒径約９μｍの着色微粒子を得た。次いで、この着色微粒子１００質量部、疎水性シリカ（日本アエロジル社製シリカ「Ｒ９７２」）１質量部を、ヘンシェルミキサで混合し、マゼンタ色トナーを得た。
【００６２】
＜実施例４＞
結着樹脂Ａ（ティコナ社製環状ポリオレフィン樹脂「ＴＭ」：Ｍｗ＝６，５００、Ｍｗ／Ｍｎ＝２）６５質量％、結着樹脂Ｂ（ティコナ社製環状ポリオレフィン樹脂「ＴＢ−１５」、Ｍｗ＝１４０，０００、Ｍｗ／Ｍｎ＝２８）１９質量％、着色剤（Ｃ．Ｉピグメントレッド５７：１）５質量％、離型剤（三井化学社製ポリプロピレンワックス「ＮＰ０５６」）１０質量％、荷電制御剤（日本カーリット社製有機ホウ素化合物「ＬＲ−１４７」）１質量％をヘンシェルミキサ（三井鉱山社製）にて混合し、二軸連続混練機により溶融混練した。その後、冷却し、衝突板式粉砕機にて粉砕分級して、質量平均粒径約９μｍの着色微粒子を得た。次いで、この着色微粒子１００質量部、疎水性シリカ（日本アエロジル社製シリカ「Ｒ９７２」）１質量部を、ヘンシェルミキサで混合し、マゼンタ色トナーを得た。
【００６３】
＜実施例５＞
結着樹脂Ａ（ティコナ社製環状ポリオレフィン樹脂「ＴＭ」：Ｍｗ＝６，５００、Ｍｗ／Ｍｎ＝２）６９質量％、結着樹脂Ｂ（ティコナ社製環状ポリオレフィン樹脂「ＴＢ−１５」、Ｍｗ＝１４０，０００、Ｍｗ／Ｍｎ＝２８）２１質量％、着色剤（Ｃ．Ｉピグメントレッド５７：１）５質量％、離型剤（クラリアント社製ポリエチレンワックス「Ｌｉｃｏｗａｘ ＰＥ１３０」）１質量％、荷電制御剤（日本カーリット社製有機ホウ素化合物「ＬＲ−１４７」）１質量％をヘンシェルミキサ（三井鉱山社製）にて混合し、二軸連続混練機により溶融混練した。その後、冷却し、衝突板式粉砕機にて粉砕分級して、質量平均粒径約９μｍの着色微粒子を得た。次いで、この着色微粒子１００質量部、疎水性シリカ（日本アエロジル社製シリカ「Ｒ９７２」）１質量部を、ヘンシェルミキサで混合し、マゼンタ色トナーを得た。
【００６４】
＜比較例１＞
結着樹脂Ａ（ティコナ社製環状ポリオレフィン樹脂「ＴＭ」：Ｍｗ＝６，５００、Ｍｗ／Ｍｎ＝２）７２質量％、結着樹脂Ｂ（ティコナ社製環状ポリオレフィン樹脂「ＴＢ−１５」、Ｍｗ＝１４０，０００、Ｍｗ／Ｍｎ＝２８）２２質量％、着色剤（Ｃ．Ｉピグメントレッド５７：１）５質量％、荷電制御剤（日本カーリット社製有機ホウ素化合物「ＬＲ−１４７」）１質量％をヘンシェルミキサ（三井鉱山社製）にて混合し、二軸連続混練機により溶融混練した。その後、冷却し、衝突板式粉砕機にて粉砕分級して、質量平均粒径約９μｍの着色微粒子を得た。次いで、この着色微粒子１００質量部、疎水性シリカ（日本アエロジル社製シリカ「Ｒ９７２」）１質量部を、ヘンシェルミキサで混合し、マゼンタ色トナーを得た。
【００６５】
＜比較例２＞
結着樹脂Ａ（ティコナ社製環状ポリオレフィン樹脂「ＴＭ」：Ｍｗ＝６，５００、Ｍｗ／Ｍｎ＝２）６９質量％、結着樹脂Ｂ（ティコナ社製環状ポリオレフィン樹脂「ＴＢ−１５」、Ｍｗ＝１４０，０００、Ｍｗ／Ｍｎ＝２８）２１質量％、着色剤（Ｃ．Ｉピグメントレッド５７：１）５質量％、離型剤（加藤洋行社輸入品「カルナバワックス１号粉末」）４質量％、荷電制御剤（日本カーリット社製有機ホウ素化合物「ＬＲ−１４７」）１質量％をヘンシェルミキサ（三井鉱山社製）にて混合し、二軸連続混練機により溶融混練した。その後、冷却し、衝突板式粉砕機にて粉砕分級して、質量平均粒径約９μｍの着色微粒子を得た。次いで、この着色微粒子１００質量部、疎水性シリカ（日本アエロジル社製シリカ「Ｒ９７２」）１質量部を、ヘンシェルミキサで混合し、マゼンタ色トナーを得た。
【００６６】
＜比較例３＞
結着樹脂Ａ（ティコナ社製環状ポリオレフィン樹脂「ＴＭ」：Ｍｗ＝６，５００、Ｍｗ／Ｍｎ＝２）７０質量％、結着樹脂Ｂ（ティコナ社製環状ポリオレフィン樹脂「ＴＢ−１５」、Ｍｗ＝１４０，０００、Ｍｗ／Ｍｎ＝２８）２１質量％、着色剤（Ｃ．Ｉピグメントレッド５７：１）５質量％、離型剤（三井化学社製ポリプロピレンワックス「ＮＰ０５６」）４質量％をヘンシェルミキサ（三井鉱山社製）にて混合し、二軸連続混練機により溶融混練した。その後、冷却し、衝突板式粉砕機にて粉砕分級して、質量平均粒径約９μｍの着色微粒子を得た。次いで、この着色微粒子１００質量部、疎水性シリカ（日本アエロジル社製シリカ「Ｒ９７２」）１質量部を、ヘンシェルミキサで混合し、マゼンタ色トナーを得た。
【００６７】
＜比較例４＞
結着樹脂Ａ（ティコナ社製環状ポリオレフィン樹脂「ＴＭ」：Ｍｗ＝６，５００、Ｍｗ／Ｍｎ＝２）６９質量％、結着樹脂Ｂ（ティコナ社製環状ポリオレフィン樹脂「ＴＢ−１５」、Ｍｗ＝１４０，０００、Ｍｗ／Ｍｎ＝２８）２１質量％、着色剤（Ｃ．Ｉピグメントレッド５７：１）５質量％、離型剤（三井化学社製ポリプロピレンワックス「ＮＰ０５６」）４質量％、荷電制御剤（中央合成化学社製サリチル酸系金属錯体「ＣＣＡ−１１１」）１質量％をヘンシェルミキサ（三井鉱山社製）にて混合し、二軸連続混練機により溶融混練した。その後、冷却し、衝突板式粉砕機にて粉砕分級して、質量平均粒径約９μｍの着色微粒子を得た。次いで、この着色微粒子１００質量部、疎水性シリカ（日本アエロジル社製シリカ「Ｒ９７２」）１質量部を、ヘンシェルミキサで混合し、マゼンタ色トナーを得た。
【００６８】
＜比較例５＞
結着樹脂Ａ（ティコナ社製環状ポリオレフィン樹脂「ＴＭ」：Ｍｗ＝６，５００、Ｍｗ／Ｍｎ＝２）６９質量％、結着樹脂Ｂ（ティコナ社製環状ポリオレフィン樹脂「ＴＢ−１５」、Ｍｗ＝１４０，０００、Ｍｗ／Ｍｎ＝２８）２１質量％、着色剤（Ｃ．Ｉピグメントレッド５７：１）５質量％、離型剤（三井化学社製ポリプロピレンワックス「ＮＰ０５６」）４質量％、荷電制御剤（オリエント化学社製フェノール系縮合物「Ｅ−８９」）１質量％をヘンシェルミキサ（三井鉱山社製）にて混合し、二軸連続混練機により溶融混練した。その後、冷却し、衝突板式粉砕機にて粉砕分級して、質量平均粒径約９μｍの着色微粒子を得た。次いで、この着色微粒子１００質量部、疎水性シリカ（日本アエロジル社製シリカ「Ｒ９７２」）１質量部を、ヘンシェルミキサで混合し、マゼンタ色トナーを得た。
【００６９】
＜比較例６＞
架橋ポリエステル樹脂（軟化点１４１℃、ガラス転移点６２℃）３６質量％、非架橋ポリエステル樹脂（軟化点９８℃、ガラス転移点６０℃）５４質量％、Ｍｗ＝１４０，０００、Ｍｗ／Ｍｎ＝２８）２１質量％、着色剤（Ｃ．Ｉピグメントレッド５７：１）５質量％、離型剤（三井化学社製ポリプロピレンワックス「ＮＰ０５６」）４質量％、荷電制御剤（日本カーリット社製有機ホウ素化合物「ＬＲ−１４７」）１質量％をヘンシェルミキサ（三井鉱山社製）にて混合し、二軸連続混練機により溶融混練した。その後、冷却し、衝突板式粉砕機にて粉砕分級して、質量平均粒径約９μｍの着色微粒子を得た。次いで、この着色微粒子１００質量部、疎水性シリカ（日本アエロジル社製シリカ「Ｒ９７２」）１質量部を、ヘンシェルミキサで混合し、マゼンタ色トナーを得た。得られたトナーの軟化点は１０９℃であった。
【００７０】
次に、以上の実施例１〜５および比較例１〜６により得られた各トナーについて、以下の評価試験の方法に基いて、生産性、熱保存性、定着性、透明性、白紙カブリ、ゴーストおよび現像安定性の各評価を行った結果、実施例１〜５において良好な結果が得られた。
【００７１】
＜生産性評価試験＞
粉砕機にて混練粗砕物を粉砕する際、トナーの母体となる粒子の収率（％）より判断する。
収率（％）＝（得られたトナー重量）／（粉砕前粗砕粉重量）×１００
また、この時トナーの体積平均粒径は９μｍ、微粉として３μｍ以下の個数割合が３．５％以下、粗粉として、１６μｍ以上の体積割合が１％以下となるように粉砕条件を調整する。粒度分布測定器はコールター社製のマルチサイザーＩＩ（アパーチャーサイズ１００μｍ）を使用した。
【００７２】
（評価基準）
○：収率が７０％以上で実用上問題ない。
×：収率が７０％未満で生産性に劣る。
【００７３】
＜熱保存性評価試験＞
得られた各トナーサンプルを、１００ｍｌガラスビーカーに１０ｇ秤量し、６０℃にて５時間加熱した後、十分冷却し、サンプルの凝集状態を評価する。
【００７４】
（評価基準）
○：トナー凝集が見られない。
△：トナーが軽く凝集しているが、すぐ崩れる。実用上問題ないレベル。
×：トナーが強く凝集している。
【００７５】
＜定着性評価試験＞
得られた各トナーサンプルを、それぞれ、定量して専用トナーカートリッジに充填した後、図１のプリンタ装置１（カシオ計算機製プリンタ装置：カラーページプレストＮ５：Ａ４横２９枚／分機）にトナーユニットＴＵ（本例ではマゼンタトナーを例としているので、画像形成ユニット５のトナーユニットＴＵ）としてセットした。そして、プリンタ装置１の定着ユニット１５において、定着温度を可変できるように改造し、定着温度１３０℃〜２００℃の範囲で１０℃毎に温度を可変し、未定着ベタ画像を定着させた際の非オフセット領域を測定した。オフセット発生の評価は、定着試験後、次いで白紙を同様に定着ユニット１５に送り、トナー汚れが生ずるかどうかで判断した。また。画像上の定着ムラ、爪痕が発生した場合もオフセットとした。
なお、プロセス速度は１２９．３ｍｍ／ｓｅｃ、用紙はゼロックスＬ紙Ａ４サイズ（重量６４ｇ／ｍ^２ ）で行った。
【００７６】
（評価基準）
○：非オフセット領域が３０℃以上ある。
×：非オフセット領域が２０℃以下である。
【００７７】
＜透明性評価試験＞
得られた各トナーサンプルを、上記同様に図１のプリンタ装置１にトナーユニットＴＵとしてセットし、通常環境（２５℃、５０％ＲＨ）において、ＯＨＰ用紙（厚み：０．１２５ｍｍ）を用いてベタ画像を印字した。なお、本試験に当たり、透明性の差異が出易いように、プリンタ装置１の定着ユニット１５のオイル塗布ローラ１５ｃは取り外した。
そして、印字された画像の一部を切取り、分光光度計（島津製作所製：ＵＶ−２４００ＰＣ）を用いて、４００ｎｍ〜７００ｎｍの波長範囲の最大透過度を測定し、以下のような評価基準で透明性評価とした。プロセス速度は３４．１ｍｍ／ｓｅｃ、定着温度は１５０℃で行った。
【００７８】
（評価基準）
◎：最大透過度が８０％以上で実用上非常に良好である。
○：最大透過度が６０％〜８０％実用上問題ない。
×：最大透過度が６０％未満で、実用上問題がある。
【００７９】
＜白紙カブリ評価試験＞
得られた各トナーサンプルを、上記同様に図１のプリンタ装置１にトナーユニットＴＵとしてセットし、白紙印字を行い、分光色差計ＳＥ−２０００（日本電色社製）でＸ値を測定し、印字前のＸ値との差をΔＸとし、カブリ評価とした。
【００８０】
（評価基準）
○：ΔＸが１．０未満であり、実用上良好である。
△：ΔＸが１．０〜１．５未満であり、実用上問題ない。
×：ΔＸが１．５以上あり、実用上問題がある。
【００８１】
＜ゴースト現象評価試験＞
得られた各トナーサンプルを、上記同様に図１のプリンタ装置１にトナーユニットＴＵとしてセットし、通常環境（２５℃、５０％ＲＨ）において、ゴースト現象の発生を確認し易い画像を印字する。目視にて、ゴースト現象発生の有無（図５参照）を確認し、ゴースト評価とした。
【００８２】
＜現像安定性評価試験＞
得られた各トナーサンプルを、上記同様に図１のプリンタ装置１にトナーユニットＴＵとしてセットし、環境条件を低温低湿環境（１０℃、２０％ＲＨ）、高温高湿環境（２８℃、８０％ＲＨ）とに分け、それぞれの環境条件下において、Ａ４サイズ１枚あたりの印字率が５％の印刷をＡ４横で連続１０，０００枚まで印字し、スタート時現像量Ａと１０，０００枚印字した後での現像量Ｂを測定し、現像量変化を求め、現像安定性評価とした。
【００８３】
表１に評価結果を纏めて示す。なお、表１中では、環状ポリオレフィン樹脂をＣＯＣ樹脂と記載し、ポリプロピレンワックスやポリエチレンワックスをそれぞれＰＰワックス、ＰＥワックスと記載してある。
【００８４】
【表１】

【００８５】
表１から、実施例１〜５のトナーは、離型剤としてポリプロピレンワックスやポリエチレンワックスの内添により透明性と定着性でいずれも良好な結果を示し、内添量の増加に伴い透明性が向上し、ポリプロピレンワックス４質量％の実施例３で最も良好な結果を示していることが判る。
これに対し離型剤を用いない比較例１のトナーは、実施例１〜５と比較して透明性、定着性の点で劣り実用的でなかった。
【００８６】
また、比較例２のトナーは、ポリプロピレンワックスやポリエチレンワックスの代わりに、カルナバワックスを用いたものであり、結果は、透明性で良好となったものの、比較例１と同様に定着性で劣る上、生産性や熱保存性でも劣っていた。
【００８７】
このように、環状ポリオレフィン樹脂を結着樹脂として使用し、離型剤としてポリプロピレンワックスやポリエチレンワックスを内添すると透明性と定着性が向上し、環状ポリオレフィン樹脂を結着樹脂としたトナーの実用化に寄与する。
尚、ポリプロピレンワックスの添加量が少ないと、比較例１に近づくことになり、実施例１のように１質量％が下限であった。一方、ワックスの添加量が多くなると、離型性効果も高くなるが、トナーの凝集や画像に斑模様が発生する等から、１０．０質量％が上限である。従って、１〜１０．０質量％の範囲で使用可能だが、好ましくは２．０〜４．０質量％程度が望ましい。
【００８８】
一方、比較例３は、最も良好な結果を示した上記実施例３に対して、荷電制御剤を添加していないだけの違いであるが、ゴーストの発生や現像安定性（とりわけ低温低湿における現像安定性）で問題が認められた。
また、比較例４および比較例５は、荷電制御剤の種類をホウ素化合物以外のものに替えた例であるが、表１の結果に示すように、ゴーストの発生と定着性、透明性で劣る結果となった。従って、環状ポリオレフィン樹脂を結着樹脂として使用する場合の荷電制御剤としてホウ素化合物が好適であることが判る。
【００８９】
なお、参考までに従来のポリエステル樹脂を結着樹脂として使用した場合の例を比較例６に示す。この比較例６は、本発明の上記実施例３に対して、結着樹脂を変更したものであるが、高温高湿における現像安定性に問題が認められた。
【００９０】
上記実施例１〜５では、着色剤としてＣ．Ｉピグメントレッド５７：１を用い、マゼンダ色トナーを例に本発明を説明した。
そこで、実際にカラー画像形成を行う上で必要な他の着色剤についても本発明の効果を確認すべく実験を行った結果を別実施例として以下に説明する。尚、この別実施例では、上記実施例３をベースに、着色剤を変更している。
【００９１】
＜別実施例１＞
結着樹脂Ａ（ティコナ社製環状ポリオレフィン樹脂「ＴＭ」：Ｍｗ＝６，５００、Ｍｗ／Ｍｎ＝２）６９質量％、結着樹脂Ｂ（ティコナ社製環状ポリオレフィン樹脂「ＴＢ−１５」、Ｍｗ＝１４０，０００、Ｍｗ／Ｍｎ＝２８）２１質量％、着色剤（Ｃ．Ｉピグメントブルー１５：３）５質量％、離型剤（三井化学社製ポリプロピレンワックス「ＮＰ０５６」）４質量％、荷電制御剤（日本カーリット社製有機ホウ素化合物「ＬＲ−１４７」）１質量％をヘンシェルミキサ（三井鉱山社製）にて混合し、二軸連続混練機により溶融混練した。その後、冷却し、衝突板式粉砕機にて粉砕分級して、質量平均粒径約９μｍの着色微粒子を得た。次いで、この着色微粒子１００質量部、疎水性シリカ（日本アエロジル社製シリカ「Ｒ９７２」）１質量部を、ヘンシェルミキサで混合し、シアン色トナーを得た。
【００９２】
＜別実施例２＞
結着樹脂Ａ（ティコナ社製環状ポリオレフィン樹脂「ＴＭ」：Ｍｗ＝６，５００、Ｍｗ／Ｍｎ＝２）６９質量％、結着樹脂Ｂ（ティコナ社製環状ポリオレフィン樹脂「ＴＢ−１５」、Ｍｗ＝１４０，０００、Ｍｗ／Ｍｎ＝２８）２１質量％、着色剤（Ｃ．Ｉピグメントイエロー１７）５質量％、離型剤（三井化学社製ポリプロピレンワックス「ＮＰ０５６」）４質量％、荷電制御剤（日本カーリット社製有機ホウ素化合物「ＬＲ−１４７」）１質量％をヘンシェルミキサ（三井鉱山社製）にて混合し、二軸連続混練機により溶融混練した。その後、冷却し、衝突板式粉砕機にて粉砕分級して、質量平均粒径約９μｍの着色微粒子を得た。次いで、この着色微粒子１００質量部、疎水性シリカ（日本アエロジル社製シリカ「Ｒ９７２」）１質量部を、ヘンシェルミキサで混合し、イエロー色トナーを得た。
【００９３】
＜別実施例３＞
結着樹脂Ａ（ティコナ社製環状ポリオレフィン樹脂「ＴＭ」：Ｍｗ＝６，５００、Ｍｗ／Ｍｎ＝２）６９質量％、結着樹脂Ｂ（ティコナ社製環状ポリオレフィン樹脂「ＴＢ−１５」、Ｍｗ＝１４０，０００、Ｍｗ／Ｍｎ＝２８）２１質量％、着色剤（カーボンブラック）５質量％、離型剤（三井化学社製ポリプロピレンワックス「ＮＰ０５６」）４質量％、荷電制御剤（日本カーリット社製有機ホウ素化合物「ＬＲ−１４７」）１質量％をヘンシェルミキサ（三井鉱山社製）にて混合し、二軸連続混練機により溶融混練した。その後、冷却し、衝突板式粉砕機にて粉砕分級して、質量平均粒径約９μｍの着色微粒子を得た。次いで、この着色微粒子１００質量部、疎水性シリカ（日本アエロジル社製シリカ「Ｒ９７２」）１質量部を、ヘンシェルミキサで混合し、ブラック色トナーを得た。
【００９４】
次に、以上の別実施例１〜３により得られた各トナーについて、上述の評価試験方法に基いて印字を行った結果、各評価項目において、いずれも表１中の実施例３と同等の、良好な結果が得られた。尚、別実施例３は、ブラックトナーであり、ＯＨＰにおける透明性には関係ないので、透明性の評価は省略している。
【００９５】
最後に、上記実施例３のトナーと別実施例１〜３のトナーを用い、図１のプリンタ装置１の各トナーユニットＴＵ（画像形成ユニット５〜８）としてセットし、種々の画像率のフルカラー画像を６千枚印字したところ、良好な画像出力が得られた。
【００９６】
【発明の効果】
以上、詳細に説明したように、本発明によれば、結着樹脂として環状ポリオレフィン樹脂を使用した場合の離型剤としてポリプロピレンワックスもしくはポリエチレンワックス、そして荷電制御剤として特定の有機ホウ素化合物の組み合わせが、生産性、熱保存性、定着特性、透明性、環境安定性に優れ、カブリ、ゴースト現象の発生が少ない静電像現像用トナーの提供を可能とし、従って、環境問題のない環状ポリオレフィン樹脂を使用したトナーの実用化が図れる。
【図面の簡単な説明】
【図１】本発明のトナーおよび現像装置が組み込まれたプリンタ装置の内部構成を模式的に示す図である。
【図２】本発明に係わるプリンタ装置の外観斜視図である。
【図３】本発明に係わるプリンタ装置の回路ブロック図である。
【図４】本発明の現像装置の主要部を模式的に示す図である。
【図５】現像時のゴースト現象の発生を説明する図であり、（ａ）は、正規の印字イメージ、（ｂ）はゴースト現象発生のイメージを示す。
【符号の説明】
１ プリンタ装置
２ 画像形成部
３ 両面印刷用搬送ユニット
４ 給紙部
５〜８ 画像形成ユニット
９ 感光体ドラム
１０ａ 帯電器
１０ｂ 印字ヘッド
１０ｃ 現像ローラ
１０ｄ 転写器
１０ｅ クリーナ
１１ 給紙カセット
１１ａ 給紙コロ
１２ 待機ローラ対
１３ 搬送ベルト
１４ 駆動ローラ
１４´ 従動ローラ
１５ 定着ユニット
１５ａ 熱ローラ
１５ｂ プレスローラ
１５ｃ オイル塗布ローラ
１６ ＭＰＦトレー
１６ａ 給紙コロ
１７ 切換フラップ
１８ａ〜１８ｅ 逆搬送ローラ対
１９ 搬送ローラ対
２０ 排紙ローラ対
２１ 排紙部
２２ 装置本体上部
２３ 装置本体下部
２４ フロントカバー
２６ Ｉ／Ｆコントローラ
２７ フレームメモリ
２８ プリンタコントローラ
２９ プリンタ印字部
３０ ＣＰＵ
３１ ＲＯＭ
３２ ＥＥＰＲＯＭ
３３ 操作パネル
３３ａ キー操作部
３３ｂ 表示部
４４ 現像装置
６１ トナーホッパ
６２ トナー
６３ 攪拌部材
６４ 供給ローラ
６５ ドクターブレード
６６ スクイシート
６７ 封止部材
６８ バイアス電源
６９ バイアス電源
７１ バイアス電源。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a toner for developing an electrostatic image, which is excellent in fixing stability and environmental stability, has good color development of a color image and transparency when printed on OHP (overhead projector) paper, and has fog and ghost phenomena. The present invention relates to an electrostatic image developing toner and a developing device with less occurrence of toner.
[0002]
[Prior art]
Image formation by electrophotography is generally obtained by developing and visualizing the toner by supplying toner to an electrostatic latent image formed on the surface of the electrostatic image carrier using a developing roller, and obtaining the image by development. This is performed by transferring the toner image to a sheet. In recent years, a non-magnetic one-component developing method has been frequently used as a toner developing method due to a demand for colorization of a printed matter and simplicity of an apparatus configuration. The toner used for such image formation usually contains a binder resin, a colorant, a release agent, and a charge control agent, and is manufactured by a known method such as a kneading and pulverizing method. Further, as a developing roller of the non-magnetic one-component developing method, a developing roller having a semiconductive elastic material such as urethane rubber at least on its surface is used.
[0003]
Styrene / acrylic resin, polyester resin, epoxy resin, etc. are used as the binder resin used for the toner, but with the spread of colorization, the color development, transparency when printing on OHP paper, and low-temperature fixability are improved. The demand for excellent toners has increased, and various binder resins having a molecular weight distribution suitable for them have been studied.
[0004]
Among the above binder resins, the polyester resin has high durability even when the molecular weight is reduced to satisfy transparency, and has a carboxyl group at the terminal of the resin, so that the pigment dispersibility is also good, so that the polyester resin is multicolored. It is becoming more frequently used for image formation.
However, many of the polyester resins contain bisphenol A, and some reports have been unfavorable in recent years from the viewpoint of environmental safety.
[0005]
Therefore, there is a polyolefin resin having a cyclic structure as one of the novel resins. Patent Documents 1 to 3 disclose inventions in which this resin is used as a binder resin for a toner.
[0006]
The invention of Patent Literature 1 is characterized in that the polyolefin resin having a cyclic structure has high safety, colorless and transparent, high moisture-proof properties, and high recyclability, so that the polyolefin resin is used and the amount of the polymer resin component is reduced. When the content is less than 50% by mass in the whole binder resin, a color toner having excellent fixability and transparency can be provided. Patent Document 1 also describes that the addition of a wax having a melting point of 60 to 170 ° C. is preferable for improving the fixing property.
[0007]
Further, in view of the disadvantage that the non-offset temperature width is narrow in the toner of the invention of Patent Document 1, the non-offset temperature width is widened and the low molecular weight resin component is obtained. Are described.
Furthermore, Patent Document 3 describes an invention in which two or more waxes having melting points in the range of 80 to 140 ° C. and different melting points are used in combination.
[0008]
[Patent Document 1]
JP-A-9-101631
[Patent Document 2]
JP 2000-284528 A
[Patent Document 3]
JP-A-2000-66438
[0009]
[Problems to be solved by the invention]
However, although the polyolefin resin having the above-mentioned cyclic structure is promising as a binder resin capable of inheriting the advantages of the polyester resin, there is still a problem to be solved practically with the above conventional technology.
[0010]
In other words, in using a polyolefin resin having a cyclic structure as a binder resin, a large amount of a high molecular resin component is effective for so-called high-temperature offset, but tends to have a low-temperature offset tendency and transparency when printed on OHP. Therefore, when the image is output to a projector, the image becomes a colorless image, which is not suitable for low-temperature fixing.
[0011]
On the other hand, if the amount of the high molecular weight resin component is reduced or the amount of the low molecular weight resin component is increased in order to improve the low temperature fixing property and transparency, the melt viscosity at the time of fixing decreases and the high temperature offset phenomenon still occurs. Exists.
[0012]
Also, wax as a release agent is basically useful for improving the offset phenomenon, but the polyolefin resin having a cyclic structure used in the present invention, when a low melting point release agent is contained. There is a problem that the glass transition point is significantly lowered, heat storage property is deteriorated, cohesive force particularly at the time of melting in fixing is reduced, and a non-offset region is narrowed, and practical problems are caused. Was.
As described above, it is difficult to satisfy the productivity, the heat storage property, and the fixing property by the conventional technology.
[0013]
The low-temperature offset refers to a phenomenon in which the heat of the fixing member is not sufficiently transmitted to the interface between the toner and the sheet, and the toner on the sheet is transferred to the fixing member. The high-temperature offset refers to a phenomenon in which toner is separated into both the fixing member and the sheet by excessively supplying heat to the toner, decreasing the viscosity of the toner and reducing the cohesive force between the toners.
[0014]
By the way, as for the charge control agent for controlling the chargeability of the toner, conventionally, there have been many containing a heavy metal, but in recent years, a heavy metal-free material has been proposed in consideration of safety. Depending on the type of the charge control agent contained in the toner, there are significant effects on image characteristics such as chargeability, transparency, fixability, fog, and image stability over time. Therefore, the selection of the charge control agent is also an important factor in the production of the toner.
[0015]
In particular, in a non-magnetic one-component developing system in which toner is charged by a blade pressed against an elastic developing roller, the image density immediately after printing is reduced or increased as shown in FIGS. The ghost phenomenon easily occurs. Accordingly, it has been desired to provide toners that can satisfy them comprehensively.
[0016]
The present invention has been made under such circumstances, and in order to suitably use a polyolefin resin having a cyclic structure, it is excellent in productivity, heat storage properties, fixing properties, transparency, environmental stability, fog, ghost phenomenon. It is an object of the present invention to provide an electrostatic image developing toner and a developing device in which generation of toner is small.
[0017]
[Means for Solving the Problems]
In order to solve the above problems, the electrostatic image developing toner of the present invention contains at least a binder resin, a colorant, a release agent, a charge control agent, and a polyolefin resin having a cyclic structure as the binder resin. It is assumed that the toner for developing an electrostatic image contains the toner.
The release agent comprises a polypropylene wax or a polyethylene wax, and the charge control agent is an organic boron compound represented by the following formula (I). The combination of the release agent and the charge control agent makes it possible to provide a toner having excellent productivity, heat preservability, fixing properties, transparency and environmental stability, and suppresses the occurrence of fog and ghost phenomena.
Embedded image

[0018]
In the electrostatic image developing toner of the present invention, the content of the release agent is desirably 1.0 to 10% by mass. If the content is less than 1.0% by mass, low-temperature offset tendency and transparency are disadvantageous. If the content exceeds 10% by mass, heat storage deteriorates and white streaks due to toner aggregation occur. Is not preferred.
[0019]
Further, in the toner for developing an electrostatic image of the present invention, it is preferable that the absorption heat peak temperature in the differential scanning calorimetry of the release agent is in the range of 80 ° C to 140 ° C in order to widen the non-offset region.
[0020]
In order to solve the above-mentioned problems, a developing device according to the present invention includes a toner hopper having an opening facing the electrostatic image bearing member and containing toner for developing an electrostatic image, and a toner hopper pressed against the electrostatic image bearing member. An elastic developing roller that is provided so as to partially face the opening, and that conveys the toner so as to develop the electrostatic image on the electrostatic image carrier while holding the toner on the surface; A doctor blade that regulates the toner to be formed in a thin layer on the elastic developing roller on the upstream side in the transport direction of the roller, and a doctor blade disposed in the toner hopper and on the upstream side in the transport direction of the elastic developing roller from the doctor blade. A supply roller that is in pressure contact with the elastic developing roller, and a light pressure contact with the elastic developing roller downstream of the opening in the transport direction of the elastic developing roller to return the toner into the toner hopper. A conductive regulating sheet member for regulating the outflow of toner from inside the toner hopper, and a bias voltage applying means for applying a bias voltage to at least the elastic developing roller and the supply roller. A resin, a colorant, a release agent, a charge control agent, and a polyolefin resin having a cyclic structure as the binder resin, wherein the release agent comprises polypropylene wax or polyethylene wax; Provided is a developing device, wherein the agent is an organic boron compound represented by the following formula (I).
Embedded image

[0021]
In the developing device of the present invention, the content of the release agent is desirably 1.0 to 10% by mass, and the peak absorption temperature of the release agent in differential scanning calorimetry is 80 ° C to 140 ° C. Is preferably within the range.
According to such a developing device of the present invention, it is possible to form an image having no fixing offset, excellent transparency, and no fogging or ghost phenomenon.
[0022]
The electrostatic image developing toner of the present invention can be manufactured by the following general manufacturing method.
First, a binder resin, a colorant, a charge control agent, a wax, and the like are uniformly mixed by a Henschel mixer or the like. Next, the mixture is melt-kneaded using a kneader, an extruder, a roll mill or the like.
[0023]
Next, the kneaded material is roughly pulverized using a hammer mill, a cutter mill, or the like, and then finely pulverized using a jet mill, a single-type mill, or the like. Thereafter, the finely pulverized material is classified using a DS (dispersion classifier), a zigzag classifier or the like. The average particle size of the toner obtained by classification is preferably 3 to 18 μm.
[0024]
To the classified toner particles, if necessary, a fluidity improver such as silica is added and uniformly mixed by a Henschel mixer or the like to produce a toner. The silica may be one whose surface has been subjected to a hydrophobic treatment using silicone oil or the like.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described, and the present invention will be described more specifically.
FIG. 1 schematically shows an internal configuration of a color image forming apparatus (printer apparatus) in which the toner and the developing device of the present invention are incorporated. First, the overall configuration of the color image forming apparatus according to the present invention will be described with reference to FIG.
[0026]
The internal configuration of the printer device 1 shown in FIG. 1 includes an image forming unit 2, a conveyance unit 3 for double-sided printing, a paper feeding unit 4, and the like. Here, the image forming unit 2 has a configuration in which four image forming units 5 to 8 are arranged side by side, and magenta (M), cyan (C), and yellow (Y) from right to left in FIG. , Black (K). Here, the magenta (M), cyan (C), and yellow (Y) image forming units 5 to 7 are configured to perform color printing by subtractive color mixture, and the black (K) image forming unit 8 is configured to perform monochrome printing. It is a configuration that can be used alone.
[0027]
Each of the image forming units 5 to 8 includes a drum unit DU and a toner unit (developing device) TU, and has the same configuration except for the toner stored in the toner hopper of the toner unit TU. M (magenta), C (cyan), Y (yellow), and black (K) color toners (non-magnetic one-component toners) are stored in the toner units TU of the image forming units 5 to 8, respectively. Each color toner is a toner excellent in fixing stability, transparency and the like of the present invention.
[0028]
Therefore, the configuration will be described by taking the image forming unit 8 including the developing device of the present invention as an example. The drum unit DU houses a photosensitive drum 9, a charger 10a, a cleaner 10e, and the like, and a print head 10b is disposed above the drum unit DU. The toner unit TU is configured such that the developing roller 10c and the toner of the present invention are stored in the developing device 44.
[0029]
The peripheral surface of the photoconductor drum 9 is made of, for example, an organic photoconductive material. Near the peripheral surface of the photoconductor drum 9, a charger 10a, a print head 10b, a developing roller 10c, a transfer unit 10d, and a cleaner 10e are provided. They are arranged sequentially. The photoreceptor drum 9 rotates in the direction of the arrow, and first, the peripheral surface of the photoreceptor drum 9 is uniformly charged by applying a charge from the charger 10a. Then, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 9 by optical writing based on print information from the print head 10b, and a toner image is formed by a developing process by the developing roller 10c. In this way, the toner image formed on the peripheral surface of the photosensitive drum 9 reaches the position of the transfer unit 10d with the rotation of the photosensitive drum 9 in the direction of the arrow, and just below the photosensitive drum 9 in the direction of the arrow. Is transferred to the sheet that moves.
[0030]
On the other hand, the paper is transported by a paper feed cassette 11, a standby roller pair 12, a transport belt 13, a drive roller 14, and the like constituting the above-described paper feed unit 4. The paper conveyed from 11 is sent to a standby roller pair 12, further sent on a conveyor belt 13 at a timing coincident with the toner image, and reaches each transfer unit 10d. Then, the toner image is transferred in each transfer unit 10d, and the sheet on which the toner image is transferred moves on the transport belt 13 in the direction of the arrow in accordance with the movement of the transport belt 13, and is subjected to heat fixing processing in the fixing unit 15. .
[0031]
Note that the above-mentioned paper includes not only paper carried out of the paper feed cassette 11 but also paper supplied from the MPF tray 16. In this case, the paper is carried in by the paper feed roller 16 a, Print processing is performed.
[0032]
The fixing unit 15 includes a heat roller 15a, a press roller 15b, an oil application roller 15c, and the like. The sheet is transferred to the sheet while the sheet is nipped and conveyed between the heat roller 15a and the press roller 15b. For example, toner images of a plurality of colors are fused and thermally fixed on paper. The oil application roller 15c has a function of applying release oil to the peripheral surface of the heat roller 15a and removing toner remaining on the heat roller 15a.
[0033]
The sheet on which the toner image has been fixed by the fixing unit 15 is conveyed upward or leftward on the sheet via the switching flap 17. The switching flap 17 is usually located at the position indicated by the broken line, and the sheet is guided to the sheet discharging unit 21 via the sheet discharging roller pair 20.
[0034]
On the other hand, the double-sided printing transport unit 3 is configured to be detachable from the apparatus main body, and is a unit to be mounted when performing double-sided printing by the printer device 1 of the present embodiment. 18e is provided. In the case of double-sided printing, the sheet is once fed upward by the switching flap 17, for example, when the rear end of the sheet reaches the pair of conveying rollers 19, the conveyance of the sheet is stopped and the sheet is further conveyed in the reverse direction. . By this control, the paper is carried into the paper transport path of the transport unit 3 for duplex printing at the lower position, the paper is sent in the reverse direction by the reverse transport roller pairs 18a to 18e, and reaches the standby roller pair 12 again, as described above. Then, the toner image is sent to the transfer unit at the same timing as the toner image, and the toner image is transferred to the back surface of the sheet.
[0035]
FIG. 2 is an external perspective view of the printer device 1 of FIG. The printer 1 shown in FIG. 1 includes an apparatus main body upper part 22 and an apparatus main body lower part 23. An operation panel 33 is disposed on the apparatus main body upper part 22, and a print paper discharge part 21 is also formed on the upper surface thereof. Have been. The operation panel 33 includes a key operation unit 33a in which a plurality of keys are provided, and a display unit 33b such as a liquid crystal display that performs display based on display information output from the CPU 30 in FIG. Further, the printing paper created in each image forming unit is output to the paper discharging unit 21 by the rotation of the paper discharging roller pair 20, and is sequentially stacked on the paper discharging unit 21.
[0036]
Further, a front cover 24 that can be opened and closed is provided on the front surface of the lower portion 23 of the apparatus main body. The front cover 24 is opened, for example, during jam clearance or maintenance.
[0037]
FIG. 3 is a circuit block diagram of the printer device 1 having the above configuration. 3, the circuit block includes an interface controller (hereinafter, referred to as an I / F controller) 26, a printer controller 28, a printer printing unit 29, a CPU 30, a ROM 31, an operation panel 33, and an EEPROM 32. The I / F controller 26 converts print data supplied from the host device into bitmap data, and develops the bitmap data in the frame memory 27. In the frame memory 27, storage areas are set for each of magenta (M), cyan (C), yellow (Y), and black (K), and data of each color is developed in a corresponding area.
[0038]
The data developed in the frame memory 27 is output to the printer controller 28 and output to the printer printing unit 29 under the control of the CPU 30. At this time, the data of each color of magenta (M), cyan (C), yellow (Y), and black (K) is supplied to the corresponding print head 10b of FIG.
[0039]
Note that the ROM 31 stores the system program of the present embodiment, and the CPU 30 performs processing according to the system program.
[0040]
Next, a basic operation of the printer 1 described above will be described. First, when the power is turned on, and the paper quality, the number of sheets to be used, the print mode, and other designations are input as a key input or a signal from a host device to be connected, the feed roller 11a is driven by a drive mechanism (not shown). By rotating, the paper loaded in the paper feed cassette 11 is fed in the direction of the standby roller pair 12. The standby roller pair 12 stops the rotation temporarily, and waits for the transport timing in a state in which the leading end of the sheet abuts on the holding portion formed by the pair of rollers.
[0041]
Subsequently, the driving roller 14 rotates in the counterclockwise direction, and the driven roller 14 'is driven to rotate in the same counterclockwise direction. As a result, the transport belt 13 circulates counterclockwise as a whole, with the upper circulating portion abutting on the four photosensitive drums 9.
[0042]
At the same time, each drum unit DU and toner unit TU are sequentially driven in accordance with the printing timing. The photosensitive drum 9 rotates clockwise, the charger 10a applies a uniform high negative charge to the peripheral surface of the photosensitive drum 9, and the print head 10b applies an image signal to the peripheral surface of the photosensitive drum 9. Exposure is performed accordingly to form a low potential portion. As a result, an electrostatic latent image composed of a high negative potential portion by the charger 10a and a low negative potential portion by exposure is formed. The developing roller 10c of the developing device 44 transfers the toner to a low potential portion of the electrostatic latent image to form a toner image on the peripheral surface of the photosensitive drum 9 (reversal development).
[0043]
At the timing when the leading end of the toner image on the peripheral surface of the photosensitive drum 9 at the most upstream position is rotated and conveyed to a point opposed to the conveyor belt 13, the standby position is set so that the print start position of the paper coincides with the point. The roller pair 12 starts rotating, and feeds the sheet to the sheet carry-in section. The sheet is attracted to the transport belt 13 and transported to the first transfer section formed by the photosensitive drum 9 and the transfer device 10d.
[0044]
The transfer device 10d applies a transfer current output from a transfer bias power supply to the sheet via the transport belt 13. The M (magenta) toner image on the photosensitive drum 9 is transferred to the sheet by the transfer current applied from the transfer device. Subsequently, a C (cyan) toner image is transferred at a second transfer portion from the upstream, and a Y (yellow) toner image is further transferred at a third transfer portion from the upstream. Then, the K (black) toner image is sequentially transferred at the fourth transfer portion from the upstream (that is, the lowest transfer portion).
[0045]
The paper on which the four color toner images have been transferred in this manner is separated from the transport belt 13 and carried into the fixing unit 15. The fixing unit 15 thermally fixes the toner image on the sheet. After the image is fixed, the sheet is discharged, for example, by a pair of discharge rollers 20 onto the upper discharge section 21 with the toner image facing down.
[0046]
The printer 1 according to the present invention has a full-color mode in which four image forming units are operated to form a full-color image, and a monochrome mode in which only one image forming unit is operated. The full-color mode can be configured by operating the three image forming units of M (magenta), C (cyan), and Y (yellow).
[0047]
In the printer device 1 operating as described above, each of the developing devices 44 according to the present invention has the following configuration in order to form a stable toner image on the photosensitive drum 9.
[0048]
FIG. 4 is a side sectional view schematically showing a main part of the developing device 44 of the present invention. The developing device 44 shown in FIG. 2 is detachable from the printer device 1 and is a toner unit TU that forms one image forming unit 8 together with the drum unit DU. The developing device 44 includes a toner hopper 61, rotatably holds a developing roller 10c made of a conductive rubber roller at a lower opening of the toner hopper 61, and accommodates a toner 62 inside the toner hopper 61, and immerses in the toner 62. And a stirring member 63 for stirring the toner.
[0049]
A supply roller 64 made of a sponge body is disposed at the lowermost part of the developing device 44 in pressure contact with the developing roller 10c. The developing roller 10c is provided with a metal leaf spring-like doctor blade 65 in pressure contact with the upper right peripheral surface thereof, and a squeeze sheet (conductive regulation sheet) 66 in contact with the lower peripheral surface thereof. I have. The squeeze sheet 66 is provided with a conductive regulating sheet bias means including a bias power supply 71. On both sides of the doctor blade 65, sealing members 67 for separating the inside and the outside of the opening of the toner hopper 61 and preventing the leakage of the toner 62 are provided.
[0050]
By the way, it is necessary to scrape off the non-developed portion of the toner 62 remaining on the peripheral surface of the developing roller 10c after the development on the photosensitive drum 9 is completed in the developing device in order to eliminate the developing memory. The sliding force of the supply roller 64 depends on the adhesion of the toner 62 to the developing roller 10c. That is, a strong rubbing force is required for a toner having a strong adhesive force, but a weak rubbing force is sufficient for a toner having a weak adhesive force. It can be said that the adhesion of the toner 62 to the developing roller 10c is substantially determined by the charging ability of the toner 62. That is, the smaller the amount of triboelectric charge, the lower the adhesive force, and therefore, the easier it is to scrape off the developing roller 10c.
[0051]
However, the frictional charge amount of the toner 62 has a close relationship with the adhesion development (so-called photoreceptor fog) to a non-image portion which occurs during development and causes a problem. Easy to generate. Therefore, in order to prevent such photoconductor fog from occurring, it is necessary to increase the frictional charge amount of the toner 62. When the frictional charge amount of the toner 62 is increased, the adhesive force to the developing roller 10c increases, so that it becomes necessary to apply a strong rubbing force to the supply roller 64.
[0052]
It is not preferable to repeat the rotation for a long period of time with such a strong rubbing force, because it causes deterioration of developing characteristics such as a decrease in toner charging ability and a decrease in fluidity. For example, when the charge amount is reduced, the above-described fogging of the photoreceptor is generated, and when the fluidity is reduced, the lack of development in halftone printing occurs.
[0053]
Therefore, in the developing device 44 of the present invention, the toner for developing an electrostatic image of the present invention is used, and first, the developing roller 10c is formed of a metal core and a cylindrical semiconductive (10) surrounding the metal core. ⁶ Ωcm) of urethane rubber, and a developing bias of “approximately −250 V” is applied to the core metal from a bias power supply 68. In addition, the supply roller 64 is made of a metal core and a cylindrical semiconductive (10 mm) surrounding the metal core. ⁶ Ωcm), and a supply bias of “approximately −500 V” is applied from a bias power supply 69 to the cored bar.
[0054]
Further, the doctor blade 65 is formed of an elastic metal plate, and a doctor bias of “approximately −500 V” is applied to the doctor blade 65 from the bias power supply 69. Then, the squeeze sheet 66 located on the upstream side of the supply roller 64 is connected to the conductive member (10 ³ Ωcm), and a sheet bias voltage in a range from 0 V (0 volt) to the developing bias voltage of the developing roller 10c is applied thereto by the bias power supply 71.
[0055]
When the squeeze sheet 66 is formed of a conductive member and a sheet bias voltage in a range from 0 V to the developing bias voltage of the developing roller 10c is applied thereto, the charge of the toner 62 attached to the developing roller 10c can be reduced. Thus, the toner of the non-development portion that has adhered to the developing roller 10c and returned can be easily scraped off even by the weak rubbing force of the supply roller 64.
[0056]
As described above, the developing device 44 of the present invention employs the contact developing (roller) system in which the developing roller 10c made of elastic rubber is pressed against the surface of the photosensitive drum 9. With the above-described apparatus configuration, high-speed and high-quality development using a non-magnetic one-component toner system is obtained.
[0057]
Using the developing device described above and the toner of the present invention manufactured by the following method, it is possible to form an image with excellent image quality such as fixability and transparency.
[0058]
【Example】
Hereinafter, an example of producing the electrostatic image developing toner of the present invention will be described, and the toner of the present invention will be described more specifically.
[0059]
<Example 1>
Binder resin A (cyclic polyolefin resin "TM-15" manufactured by Ticona Corporation: Mw = 6,500, Mw / Mn = 2) 72% by mass, binder resin B (cyclic polyolefin resin "TB-15" manufactured by Ticona Corporation, Mw = 140,000, 21% by mass of Mw / Mn = 28), 5% by mass of colorant (CI Pigment Red 57: 1), 1% by mass of release agent (polypropylene wax "NP056" manufactured by Mitsui Chemicals, Inc.), charge control 1 mass% of an agent (organic boron compound “LR-147” manufactured by Nippon Carlit Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and melt-kneaded by a twin-screw continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate type pulverizer to obtain colored fine particles having a mass average particle size of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica "R972" manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a magenta toner.
[0060]
<Example 2>
Binder resin A (cyclic polyolefin resin “TM” manufactured by Ticona Co., Ltd .: Mw = 6,500, Mw / Mn = 2) 71 mass%, binder resin B (cyclic polyolefin resin “TB-15” manufactured by Ticona Corporation, Mw = 140,000, 21% by mass of Mw / Mn = 28), 5% by mass of colorant (CI Pigment Red 57: 1), 2% by mass of release agent (polypropylene wax "NP056" manufactured by Mitsui Chemicals, Inc.), charge control 1 mass% of an agent (organic boron compound “LR-147” manufactured by Nippon Carlit Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and melt-kneaded by a twin-screw continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate type pulverizer to obtain colored fine particles having a mass average particle size of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica "R972" manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a magenta toner.
[0061]
<Example 3>
Binder resin A (cyclic polyolefin resin "TB-15" manufactured by Ticona Co., Ltd., "TB-15", Mw = 6,500, Mw / Mn = 2); 140,000, 21% by weight of Mw / Mn = 28), 5% by weight of a coloring agent (CI Pigment Red 57: 1), 4% by weight of a release agent (polypropylene wax "NP056" manufactured by Mitsui Chemicals, Inc.), charge control 1 mass% of an agent (organic boron compound “LR-147” manufactured by Nippon Carlit Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and melt-kneaded by a twin-screw continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate type pulverizer to obtain colored fine particles having a mass average particle size of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica "R972" manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a magenta toner.
[0062]
<Example 4>
65% by mass of binder resin A (cyclic polyolefin resin “TM” manufactured by Ticona Co., Ltd .: Mw = 6,500, Mw / Mn = 2), binder resin B (cyclic polyolefin resin “TB-15” manufactured by Ticona Co., Mw = 140,000, Mw / Mn = 28) 19% by mass, colorant (CI Pigment Red 57: 1) 5% by mass, release agent (Mitsui Chemicals Ltd. polypropylene wax "NP056") 10% by mass, charge control 1 mass% of an agent (organic boron compound “LR-147” manufactured by Nippon Carlit Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and melt-kneaded by a twin-screw continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate type pulverizer to obtain colored fine particles having a mass average particle size of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica "R972" manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a magenta toner.
[0063]
<Example 5>
Binder resin A (cyclic polyolefin resin "TB-15" manufactured by Ticona Co., Ltd., "TB-15", Mw = 6,500, Mw / Mn = 2); 140,000, 21% by mass of Mw / Mn = 28), 5% by mass of a coloring agent (CI Pigment Red 57: 1), 1% by mass of a release agent (polyethylene wax "Licowax PE130" manufactured by Clariant), charge control 1 mass% of an agent (organic boron compound “LR-147” manufactured by Nippon Carlit Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and melt-kneaded by a twin-screw continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate type pulverizer to obtain colored fine particles having a mass average particle size of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica "R972" manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a magenta toner.
[0064]
<Comparative Example 1>
Binder resin A (cyclic polyolefin resin "TM-15" manufactured by Ticona Corporation: Mw = 6,500, Mw / Mn = 2) 72% by mass, binder resin B (cyclic polyolefin resin "TB-15" manufactured by Ticona Corporation, Mw = 140,000, Mw / Mn = 28) 22% by mass, colorant (CI Pigment Red 57: 1) 5% by mass, charge control agent (Organic boron compound "LR-147" manufactured by Nippon Carlit Co., Ltd.) 1% by mass Were mixed in a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and melt-kneaded by a twin-screw continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate type pulverizer to obtain colored fine particles having a mass average particle size of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica "R972" manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a magenta toner.
[0065]
<Comparative Example 2>
Binder resin A (cyclic polyolefin resin "TB-15" manufactured by Ticona Co., Ltd., "TB-15", Mw = 6,500, Mw / Mn = 2); 140,000, 21% by weight of Mw / Mn = 28), 5% by weight of colorant (CI Pigment Red 57: 1), 4% by weight of release agent (Carnauba wax No. 1 powder imported by Kato Yoko Co., Ltd.) And 1% by mass of a charge control agent (organic boron compound “LR-147” manufactured by Nippon Carlit Co., Ltd.) in a Henschel mixer (Mitsui Mining Co., Ltd.) and melt-kneaded by a twin-screw continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate type pulverizer to obtain colored fine particles having a mass average particle size of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica "R972" manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a magenta toner.
[0066]
<Comparative Example 3>
70% by mass of binder resin A (cyclic polyolefin resin “TM” manufactured by Ticona), Mw = 6,500, Mw / Mn = 2, binder resin B (cyclic polyolefin resin “TB-15” manufactured by Ticona), Mw = 140,000, 21% by weight of Mw / Mn = 28), 5% by weight of a coloring agent (CI Pigment Red 57: 1), and 4% by weight of a release agent (polypropylene wax "NP056" manufactured by Mitsui Chemicals, Inc.) (Made by Mitsui Mining Co., Ltd.) and melt-kneaded by a twin-screw continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate type pulverizer to obtain colored fine particles having a mass average particle size of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica "R972" manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a magenta toner.
[0067]
<Comparative Example 4>
Binder resin A (cyclic polyolefin resin "TB-15" manufactured by Ticona Co., Ltd., "TB-15", Mw = 6,500, Mw / Mn = 2); 140,000, 21% by weight of Mw / Mn = 28), 5% by weight of a coloring agent (CI Pigment Red 57: 1), 4% by weight of a release agent (polypropylene wax "NP056" manufactured by Mitsui Chemicals, Inc.), charge control 1% by mass of an agent (salicylic acid-based metal complex “CCA-111” manufactured by Chuo Gosei Kagaku Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and melt-kneaded by a twin-screw continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate type pulverizer to obtain colored fine particles having a mass average particle size of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica "R972" manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a magenta toner.
[0068]
<Comparative Example 5>
Binder resin A (cyclic polyolefin resin "TB-15" manufactured by Ticona Co., Ltd., "TB-15", Mw = 6,500, Mw / Mn = 2); 140,000, 21% by weight of Mw / Mn = 28), 5% by weight of a coloring agent (CI Pigment Red 57: 1), 4% by weight of a release agent (polypropylene wax "NP056" manufactured by Mitsui Chemicals, Inc.), charge control 1% by mass of an agent (phenolic condensate "E-89" manufactured by Orient Chemical Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and melt-kneaded by a twin-screw continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate type pulverizer to obtain colored fine particles having a mass average particle size of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica "R972" manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a magenta toner.
[0069]
<Comparative Example 6>
36% by mass of crosslinked polyester resin (softening point 141 ° C., glass transition point 62 ° C.), 54% by mass of non-crosslinked polyester resin (softening point 98 ° C., glass transition point 60 ° C.), Mw = 140,000, Mw / Mn = 28 21% by mass), 5% by mass of a coloring agent (CI Pigment Red 57: 1), 4% by mass of a release agent (polypropylene wax "NP056" manufactured by Mitsui Chemicals, Inc.), and a charge control agent (organic boron compound manufactured by Nippon Carlit Co. 1% by mass of "LR-147") was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and melt-kneaded by a twin-screw continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate type pulverizer to obtain colored fine particles having a mass average particle size of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica "R972" manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a magenta toner. The softening point of the obtained toner was 109 ° C.
[0070]
Next, for each of the toners obtained in Examples 1 to 5 and Comparative Examples 1 to 6, based on the following evaluation test method, productivity, heat storage property, fixing property, transparency, white paper fog, As a result of evaluation of ghost and development stability, good results were obtained in Examples 1 to 5.
[0071]
<Productivity evaluation test>
When the kneaded and crushed material is pulverized by a pulverizer, the determination is made based on the yield (%) of particles serving as the base of the toner.
Yield (%) = (weight of obtained toner) / (weight of crushed powder before pulverization) × 100
At this time, the pulverization conditions are adjusted so that the volume average particle diameter of the toner is 9 μm, the number ratio of fine particles of 3 μm or less is 3.5% or less, and the volume ratio of coarse particles is 16 μm or more is 1% or less. As the particle size distribution analyzer, Multisizer II (aperture size: 100 μm) manufactured by Coulter Co., Ltd. was used.
[0072]
(Evaluation criteria)
：: The yield is 70% or more and there is no practical problem.
X: Productivity is poor when the yield is less than 70%.
[0073]
<Heat storage evaluation test>
10 g of each of the obtained toner samples is weighed in a 100 ml glass beaker, heated at 60 ° C. for 5 hours, sufficiently cooled, and the aggregation state of the sample is evaluated.
[0074]
(Evaluation criteria)
：: No toner aggregation was observed.
Δ: The toner is slightly aggregated, but collapses immediately. Practically no problem level.
X: The toner is strongly aggregated.
[0075]
<Fixability evaluation test>
After quantifying each of the obtained toner samples and filling them in a dedicated toner cartridge, the toner unit TU is placed in the printer 1 (a printer manufactured by Casio Computer: Color Page Press N5: A4 width 29 sheets / min. Machine) in FIG. (In this example, magenta toner is used as an example, and thus the toner is set as the toner unit TU of the image forming unit 5). Then, the fixing unit 15 of the printer device 1 is modified so that the fixing temperature can be changed, and the fixing temperature is changed every 10 ° C. in the range of 130 ° C. to 200 ° C. to fix the unfixed solid image. The non-offset area was measured. After the fixing test, the evaluation of the occurrence of the offset was performed by sending a blank sheet to the fixing unit 15 in the same manner and determining whether or not toner stains occurred. Also. Offset was also determined when fixing unevenness and nail marks occurred on the image.
The process speed was 129.3 mm / sec, and the paper was Xerox L paper A4 size (weight: 64 g / m2). ² ).
[0076]
(Evaluation criteria)
：: The non-offset region is 30 ° C. or more.
X: The non-offset region is 20 ° C. or less.
[0077]
<Transparency evaluation test>
Each of the obtained toner samples is set as a toner unit TU in the printer device 1 of FIG. 1 in the same manner as described above, and is solid-filled using OHP paper (thickness: 0.125 mm) in a normal environment (25 ° C., 50% RH). Images were printed. In this test, the oil application roller 15c of the fixing unit 15 of the printer device 1 was removed so that a difference in transparency was easily generated.
Then, a part of the printed image is cut out, and the maximum transmittance in a wavelength range of 400 nm to 700 nm is measured using a spectrophotometer (UV-2400PC, manufactured by Shimadzu Corporation). Sex evaluation was performed. The process speed was 34.1 mm / sec and the fixing temperature was 150 ° C.
[0078]
(Evaluation criteria)
A: Practically very good with a maximum transmittance of 80% or more.
：: Maximum transmittance of 60% to 80% No problem in practical use.
X: The maximum transmittance is less than 60%, and there is a practical problem.
[0079]
<Blank fog evaluation test>
Each of the obtained toner samples is set as the toner unit TU in the printer device 1 of FIG. 1 in the same manner as described above, printing is performed on a blank sheet, and the X value is measured with a spectral colorimeter SE-2000 (manufactured by Nippon Denshoku Co., Ltd.). The difference between the X value before printing and ΔX was defined as fog evaluation.
[0080]
(Evaluation criteria)
：: ΔX is less than 1.0, which is practically good.
Δ: ΔX is 1.0 to less than 1.5, and there is no practical problem.
×: ΔX is 1.5 or more, which is problematic in practical use.
[0081]
<Ghost phenomenon evaluation test>
Each of the obtained toner samples is set as a toner unit TU in the printer device 1 of FIG. 1 in the same manner as described above, and an image in which the occurrence of a ghost phenomenon is easily confirmed is printed in a normal environment (25 ° C., 50% RH). The presence or absence of the occurrence of a ghost phenomenon (see FIG. 5) was visually checked, and the ghost was evaluated.
[0082]
<Development stability evaluation test>
Each of the obtained toner samples is set as the toner unit TU in the printer device 1 of FIG. 1 in the same manner as described above, and the environmental conditions are a low temperature and low humidity environment (10 ° C., 20% RH) and a high temperature and high humidity environment (28 ° C., 80% RH), and under each environmental condition, printing with a printing rate of 5% per A4 size sheet is continuously printed up to 10,000 sheets in A4 width, and the development amount A at start and 10,000 sheets printing After that, the development amount B was measured, the change in the development amount was obtained, and the development stability was evaluated.
[0083]
Table 1 summarizes the evaluation results. In Table 1, the cyclic polyolefin resin is described as COC resin, and the polypropylene wax and polyethylene wax are described as PP wax and PE wax, respectively.
[0084]
[Table 1]

[0085]
From Table 1, it can be seen that the toners of Examples 1 to 5 showed good results in transparency and fixability by internally adding a polypropylene wax or polyethylene wax as a release agent, and the transparency increased with an increase in the amount of internal addition. It can be seen that the results were improved, and the best result was obtained in Example 3 in which the polypropylene wax was 4% by mass.
On the other hand, the toner of Comparative Example 1 using no release agent was inferior in transparency and fixing property as compared with Examples 1 to 5, and was not practical.
[0086]
Further, the toner of Comparative Example 2 used carnauba wax instead of polypropylene wax or polyethylene wax. As a result, although the transparency was good, the fixing property was inferior as in Comparative Example 1. Also, the productivity and the heat preservability were inferior.
[0087]
As described above, when a cyclic polyolefin resin is used as a binder resin and a polypropylene wax or a polyethylene wax is internally added as a release agent, transparency and fixability are improved, and a toner using a cyclic polyolefin resin as a binder resin is put into practical use. To contribute.
In addition, when the addition amount of the polypropylene wax was small, it was closer to Comparative Example 1, and as in Example 1, the lower limit was 1% by mass. On the other hand, when the added amount of the wax increases, the releasability effect also increases, but the upper limit is 10.0% by mass because aggregation of the toner and mottled images occur. Therefore, it can be used in the range of 1 to 10.0% by mass, but preferably about 2.0 to 4.0% by mass.
[0088]
On the other hand, Comparative Example 3 is different from Example 3 in which the best result was shown, except that the charge control agent was not added. However, ghost generation and development stability (particularly, development at low temperature and low humidity) were observed. Stability).
Further, Comparative Examples 4 and 5 are examples in which the type of the charge control agent was changed to one other than the boron compound. However, as shown in the results of Table 1, ghost generation, fixability, and transparency were inferior. The result was. Therefore, it is understood that a boron compound is suitable as a charge control agent when a cyclic polyolefin resin is used as a binder resin.
[0089]
For reference, an example in which a conventional polyester resin is used as a binder resin is shown in Comparative Example 6. Comparative Example 6 was different from Example 3 of the present invention in that the binder resin was changed. However, a problem was recognized in the development stability at high temperature and high humidity.
[0090]
In Examples 1 to 5, C.I. The present invention has been described using M.I. Pigment Red 57: 1 and a magenta toner as an example.
Therefore, the results of an experiment conducted to confirm the effects of the present invention with respect to other coloring agents necessary for actually forming a color image will be described below as another embodiment. In this alternative embodiment, the colorant is changed based on the third embodiment.
[0091]
<Another Example 1>
Binder resin A (cyclic polyolefin resin "TB-15" manufactured by Ticona Co., Ltd., "TB-15", Mw = 6,500, Mw / Mn = 2); 140,000, 21% by weight of Mw / Mn = 28), 5% by weight of colorant (CI Pigment Blue 15: 3), 4% by weight of release agent (polypropylene wax "NP056" manufactured by Mitsui Chemicals, Inc.), charge control 1 mass% of an agent (organic boron compound “LR-147” manufactured by Nippon Carlit Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and melt-kneaded by a twin-screw continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate type pulverizer to obtain colored fine particles having a mass average particle size of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (Silica “R972” manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a cyan toner.
[0092]
<Another Example 2>
Binder resin A (cyclic polyolefin resin "TB-15" manufactured by Ticona Co., Ltd., "TB-15", Mw = 6,500, Mw / Mn = 2); 140,000, 21% by mass of Mw / Mn = 28), 5% by mass of a colorant (CI Pigment Yellow 17), 4% by mass of a release agent (polypropylene wax "NP056" manufactured by Mitsui Chemicals, Inc.), a charge control agent ( 1% by mass of an organic boron compound “LR-147” manufactured by Nippon Carlit Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and melt-kneaded by a twin-screw continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate type pulverizer to obtain colored fine particles having a mass average particle size of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica "R972" manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a yellow toner.
[0093]
<Another embodiment 3>
69% by mass of binder resin A (cyclic polyolefin resin “TM” manufactured by Ticona Corporation: Mw = 6,500, Mw / Mn = 2), binder resin B (cyclic polyolefin resin “TB-15” manufactured by Ticona Corporation, Mw = 140,000, 21% by weight of Mw / Mn = 28), 5% by weight of colorant (carbon black), 4% by weight of mold release agent (polypropylene wax "NP056" manufactured by Mitsui Chemicals, Inc.), charge control agent (manufactured by Nippon Carlit Co., Ltd.) 1% by mass of an organic boron compound “LR-147”) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and melt-kneaded by a twin-screw continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate type pulverizer to obtain colored fine particles having a mass average particle size of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica "R972" manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a black toner.
[0094]
Next, printing was performed on each of the toners obtained in the above Examples 1 to 3 based on the above-described evaluation test method. As a result, in each of the evaluation items, each was the same as Example 3 in Table 1. And good results were obtained. Since the third embodiment is a black toner and has no relation to the transparency in the OHP, the evaluation of the transparency is omitted.
[0095]
Finally, using the toner of the third embodiment and the toners of the first to third embodiments, the toner units TU (image forming units 5 to 8) of the printer 1 of FIG. When 6,000 images were printed, good image output was obtained.
[0096]
【The invention's effect】
As described above in detail, according to the present invention, a combination of a polypropylene wax or a polyethylene wax as a release agent when a cyclic polyolefin resin is used as a binder resin, and a specific organic boron compound as a charge control agent is used. It is possible to provide a cyclic polyolefin resin which is excellent in productivity, heat preservability, fixing properties, transparency and environmental stability, and has less fogging and ghost phenomenon. The used toner can be put to practical use.
[Brief description of the drawings]
FIG. 1 is a diagram schematically illustrating an internal configuration of a printer in which a toner and a developing device of the present invention are incorporated.
FIG. 2 is an external perspective view of a printer device according to the present invention.
FIG. 3 is a circuit block diagram of a printer device according to the present invention.
FIG. 4 is a diagram schematically showing a main part of the developing device of the present invention.
5A and 5B are diagrams for explaining the occurrence of a ghost phenomenon during development, wherein FIG. 5A shows a regular print image, and FIG. 5B shows an image of the occurrence of a ghost phenomenon.
[Explanation of symbols]
1 Printer device
2 Image forming unit
3 Double-sided printing transport unit
4 Paper feed unit
5-8 Image forming unit
9 Photoconductor drum
10a Charger
10b print head
10c developing roller
10d transfer unit
10e cleaner
11 Paper cassette
11a Paper feed roller
12 Standby roller pair
13 Conveyor belt
14 Drive roller
14 'driven roller
15 Fixing unit
15a Heat roller
15b Press roller
15c oil application roller
16 MPF tray
16a Paper feed roller
17 Switching flap
18a-18e Reverse transport roller pair
19 Transport roller pair
20 paper output roller pair
21 Paper output unit
22 Upper unit
23 Lower part of main unit
24 Front cover
26 I / F controller
27 frame memory
28 Printer Controller
29 Printer printing unit
30 CPU
31 ROM
32 EEPROM
33 Operation panel
33a key operation section
33b display
44 Developing device
61 Toner hopper
62 Toner
63 Stirring member
64 supply roller
65 Doctor Blade
66 Squishy sheet
67 Sealing member
68 bias power supply
69 bias power supply
71 Bias power supply.

Claims (6)

A binder resin, a colorant, a release agent, an electrostatic image developing toner containing at least a charge control agent, wherein the binder resin includes a polyolefin resin having a cyclic structure, and the release agent is polypropylene wax or polyethylene. An electrostatic image developing toner comprising a wax, wherein the charge control agent is an organic boron compound represented by the following formula (I).

The electrostatic image developing toner according to claim 1, wherein the content of the release agent is 1.0 to 10% by mass. 3. The electrostatic image developing toner according to claim 1, wherein the release agent has an absorption calorie peak temperature in a differential scanning calorimetry in a range of 80 ° C. to 140 ° C. 4. A toner hopper having an opening to face the electrostatic image carrier and containing an electrostatic image developing toner;
An elastic developing roller that is provided so as to partially face the opening so as to be in pressure contact with the electrostatic image carrier, and conveys the toner on the surface thereof to develop the electrostatic image on the electrostatic image carrier. When,
A doctor blade that regulates the toner so as to be formed in a thin layer on the elastic developing roller on the upstream side in the transport direction of the elastic developing roller from the opening;
A supply roller which is disposed in the toner hopper and is in pressure contact with the elastic developing roller on the upstream side in the transport direction of the elastic developing roller from the doctor blade;
A conductivity regulation that lightly contacts the elastic developing roller on the downstream side in the transport direction of the elastic developing roller from the opening to allow the toner to return to the toner hopper and at the same time restrict the outflow of the toner from the toner hopper. A sheet member,
A bias voltage applying unit that applies a bias voltage to at least the elastic developing roller and the supply roller,
The toner contains at least a binder resin, a colorant, a release agent, and a charge control agent, and includes a polyolefin resin having a cyclic structure as the binder resin, wherein the release agent is polypropylene wax or polyethylene wax. Wherein the charge control agent is an organic boron compound represented by the following formula (I):

The developing device according to claim 4, wherein the content of the release agent is 1.0 to 10% by mass. The developing device according to claim 4, wherein a peak temperature of an absorption calorie of the release agent in differential scanning calorimetry is in a range of 80 ° C. to 140 ° C. 7.

Images