JP4103650B2 - Toner production method - Google Patents

Description

【０２５９】
【表２】

【０２６０】
［３］評価
以上のようにして得られた各トナーについて、定着良好域、現像耐久性、保存性、帯電特性、転写効率、透明性の評価を行った。
［３．１］定着良好域
まず、前述した図７〜図１４、図１７に示すような定着装置を作製した。この定着装置では、トナーがニップ部を通過するのに要する時間Δｔを０．０５秒に設定した。この定着装置を用いて図５、図６に示すような画像形成装置（カラープリンタ）を作製した。この画像形成装置を用いて、未定着の画像サンプルを採取し、当該画像形成装置の定着装置で、以下のような試験を実施した。なお、採取するサンプルのベタは付着量を０．４０〜０．５０ｍｇ／ｃｍ^２に調整した。画像形成装置を構成する定着装置の定着ローラの表面温度を所定温度に設定した状態で、未定着のトナー像が転写された用紙（セイコーエプソン社製、上質普通紙）を、定着装置の内部に導入することにより、トナー像を用紙に定着させ、定着後におけるオフセットの発生の有無を目視で確認した。
【０２６１】
同様に、定着ローラの表面の設定温度を１００〜２５０℃の範囲で順次変更していき、各温度でのオフセットの発生の有無を確認し、オフセットが発生しなかった温度範囲を、「定着良好域」として求め、以下の３段階の基準に従い評価した。
◎：定着良好域の幅が６０℃以上である。
○：定着良好域の幅が３５℃以上６０℃未満である。
×：定着良好域の幅が３５℃未満である。
【０２６２】
［３．２］現像耐久性
前記［３．１］で用いた画像形成装置の現像装置にトナーを３０ｇセットした後、無補給でエージングを行い、現像ローラへのフィルミングが発生するまでの時間を測定し、以下の３段階の基準に従い評価した。
◎：エージング開始後、１２０分以上経過しても、フィルミングの発生は認められなかった。
○：エージング開始後、６０〜１２０分でフィルミングが発生。
×：エージング開始後、６０分未満でフィルミングが発生。
【０２６３】
［３．３］保存性
各実施例および各比較例のトナーを、それぞれ１０ｇずつサンプル瓶に入れ、５０℃の恒温槽内に４８時間放置した後、固まり（凝集）の有無を目視で確認し、以下の３段階の基準に従い評価した。
◎：固まり（凝集）の存在が全く認められなかった。
○：小さい固まり（凝集）がわずかに認められた。
×：固まり（凝集）がはっきりと認められた。
【０２６４】
［３．４］帯電特性
前記［３．１］で用いた画像形成装置において、印字途中で画像形成装置を停止させ、カートリッジを取り外し、粉黛帯電量分布測定装置（ホソカワミクロン社製、E-spart analyzer）を用いて、帯電量分布を測定し、その結果から、帯電量および逆帯電量としてプラス帯電量を求めた。
帯電量については、初期帯電量と、１０００枚印字後（１Ｋ後）の帯電量について求めた。
【０２６５】
１０００枚印字後（１Ｋ後）の帯電量については、以下の４段階の基準に従い評価した。
◎：初期帯電量からの変化量（絶対値）が０．５μＣ／ｇ未満。
○：初期帯電量からの変化量（絶対値）が０．５μＣ／ｇ以上１μＣ／ｇ未満。
△：初期帯電量からの変化量（絶対値）が１μＣ／ｇ以上３μＣ／ｇ未満。
×：初期帯電量からの変化量（絶対値）が３μＣ／ｇ以上。
また、逆帯電性のトナーについては、全トナー量に対する存在比率を求め、逆帯電性のトナーの存在比率が３ｗｔ％未満の場合は○、逆帯電性のトナーの存在比率が３ｗｔ％以上の場合は×とした。
【０２６６】
［３．５］転写効率
前記［３．１］で用いた画像形成装置を用いて、以下のように評価した。
感光体（像担持体）への現像工程直後（転写前）の感光体上のトナーと、転写後（印刷後）の感光体上のトナーとを、別々のテープを用いて採取し、それぞれの重量を測定した。転写前の感光体上のトナー重量をＷ_ｂ［ｇ］、転写後の感光体上のトナー重量をＷ_ａ［ｇ］としたとき、（Ｗ_ｂ−Ｗ_ａ）×１００／Ｗ_ｂとして求められる値を、転写効率とした。
【０２６７】
［３．６］透明性
まず、微量のトナーを２枚のスライドガラス間に挿し込み、ホットプレート上で溶融させ、その後、徐冷した。トナーを構成する樹脂が完全に固化するまで放置し、その後、ＨＡＺＥメーター（日本電色工業社製、ＭＯＤＥＬ１００１ＤＰ）でＨＡＺＥ値を測定し、ＨＡＺＥ値が５０未満のものを○、ＨＡＺＥ値が５０以上のものを×として、評価した。ＨＡＺＥ値は、拡散透過率を全透過率で除した値であり、トナー中の各成分の分散性が良い程、この値は小さくなる。
これらの結果を表３にまとめて示した。
【０２６８】
【表３】

【０２６９】
表３から明らかなように、本発明のトナーは、いずれも、現像耐久性に優れ、幅広い温度領域で、優れた定着性を発揮するものであった。また、本発明のトナーは、保存性にも優れていた。特に本発明のトナーでは、帯電特性、転写効率、透明性を保持しつつ、優れた現像耐久性、定着性、保存性を発揮するものであった。特に、ブロックポリエステル、非晶性ポリエステルの組成が好ましく、かつ、第１の領域の平均粒径が最適な大きさである実施例１、２、４、７のトナーでは、特に優れた結果が得られた。
【０２７０】
これに対して、比較例のトナーでは、十分な特性が得られなかった。
特に、ブロックポリエステルを含まない比較例１のトナーでは、機械的ストレスに弱く、現像耐久性、保存性が特に劣っていた。
また、非晶性ポリエステルを含まない比較例２のトナーは、定着強度が弱く、定着性に劣っていた。また、比較例２のトナーは、透明性にも劣っていた。
【０２７１】
また、ブロックポリエステルを用いず、非晶性ポリエステルと、結晶性の高いポリエステルＤとを併用した比較例３、４のトナーは、樹脂同士の親和性（ブロックポリエステルと結晶性ポリエステルとの親和性）に劣り、トナー粒子中においてマクロ相分離が発生しており、定着性と耐久性が特に劣っていた。
また、第１の領域に着色剤が偏在している比較例４では、耐久性が特に低かった。
【０２７２】
また、着色剤を含まない比較例５、６のトナーでは、比較的優れた現像耐久性を有していたが、いずれも、実施例１〜９のトナーに比べると劣っていた。このことから、本発明のように、主として非晶性ポリエステルで構成された第２の領域に、着色剤を偏在させることにより、（ブロックポリエステルと非晶性ポリエステルとの配合比等に関わらず、）トナーの耐久性を向上させる効果が得られることがわかる。
【０２７３】
また、前記各トナーについて、上記の定着装置のニップ部を通過させ、トナー粒子の前記ニップ部の通過時間Δｔ［秒］における、緩和弾性率Ｇ（ｔ）の変化量を測定したところ、実施例１〜９の各トナーでは、緩和弾性率Ｇ（ｔ）の変化量は、いずれも１００［Ｐａ］以下であった。なお、トナー粒子が通過する際における、ニップ部の温度は、１８０℃であった。
【０２７４】
また、着色剤として、シアン顔料（Ｐ．Ｒ．１５：３）に代わり、キナクリドン（Ｐ．Ｒ．１２２）、ピグメントレッド５７：１、Ｃ．Ｉ．ピグメントイエロー９３、カーボンブラックを用いた以外は、前記各実施例および前記各比較例と同様にして、トナーを作製し、これらの各トナーについても前記と同様の評価を行った。その結果、前記各実施例および前記各比較例と同様の結果が得られた。
【図面の簡単な説明】
【図１】 本発明のトナーの製造方法の第１実施形態で用いる混練機、冷却機の構成の一例を模式的に示す縦断面図である。
【図２】 ブロックポリエステルについて示差走査熱量分析を行ったときに得られる、ブロックポリエステルの融点付近での示差走査熱量分析曲線のモデル図である。
【図３】 軟化点解析用フローチャートである。
【図４】 トナー中に含まれるトナー粒子から遊離したルチルアナターゼ型の酸化チタンの量を測定する方法を説明するための図である。
【図５】 本発明の画像形成装置（本発明のトナーが好適に適用される画像形成装置）の好適な実施形態を示す全体構成図である。
【図６】 図５の画像形成装置が有する現像装置の断面図である。
【図７】 図５の画像形成装置に用いられる本発明の定着装置の詳細構造を示し、一部破断面を示す斜視図である。
【図８】 図７の定着装置の要部断面図である。
【図９】 図７の定着装置を構成する剥離部材の斜視図である。
【図１０】 図７の定着装置を構成する剥離部材の取付状態を示す側面図である。
【図１１】 図７の定着装置を上面から見た正面図である。
【図１２】 定着ニップ部の出口における接線に対する、剥離部材の配置角度を説明するための模式図である。
【図１３】 定着ローラ、加圧ローラの形状と、定着ニップ部の形状を模式的に示す図である。
【図１４】 図１３（ａ）のＸ−Ｘ線における断面図である。
【図１５】 定着ローラ、加圧ローラの形状と、定着ニップ部の形状を模式的に示す図である。
【図１６】 図１５（ａ）のＹ−Ｙ線における断面図である。
【図１７】 定着ローラと、剥離部材とのギャップを説明するための断面図である。
【図１８】 本発明のトナーの製造方法の第２実施形態で用いる混練機、冷却機の構成の一例を模式的に示す縦断面図である。
【符号の説明】
１、１’……混練機 １２……プロセス部 １２１……バレル １２２、１２３……スクリュー １２４……固定部材 １３……ヘッド部 １３１……内部空間 １３２……押出口 １３３……横断面積漸減部 １４……フィーダー ２……第１の混練部 ２１……フィーダー ２２……プロセス部 ２２１……バレル
２２２、２２３……スクリュー ３……第２の混練部 ３１……フィーダー ３２……プロセス部 ３２１……バレル ３２２、３２３……スクリュー ３２４……固定部材 ４……接続部 ５……ヘッド部 ５１……内部空間 ５２……押出口 ５３……横断面積漸減部 ６……冷却機 ６１、６２、６３、６４……ロール ６１１、６２１、６３１、６４１……回転軸 ６５、６６……ベルト
６７……排出部 ７……第１の原料 ８……第１の混練物 ９……第２の原料
１０……第２の混練物 １０００……画像形成装置 ２０……装置本体 ３０……像担持体 ４０……帯電装置 ５０……露光装置 ６０……ロータリー現像装置 ６００……支持フレーム ６０１……ハウジング ６０３……供給ローラ
６０４……現像ローラ ６０５……規制ブレード ６０５ａ……板状部材 ６０５ｂ……弾性部材 ６０Ｙ……イエロー用現像装置 ６０Ｍ……マゼンタ用現像装置 ６０Ｃ……シアン用現像装置 ６０Ｋ……ブラック用現像装置 ７０……中間転写装置 ９０……駆動ローラ １００……従動ローラ １１０……中間転写ベルト １２０……一次転写ローラ １３０……転写ベルトクリーナ １４０……二次転写ローラ １５０……給紙カセット １６０……ピックアップローラ１７０……記録媒体搬送路 １９０……定着装置 ２００……排紙トレイ ２１０……定着ローラ（加熱定着部材） ２１０ａ……熱源 ２１０ｂ……筒体
２１０ｃ……弾性層 ２１０ｄ……回転軸 ２２０……加圧ローラ（加圧部材）
２２０ｂ……筒体 ２２０ｃ……弾性層 ２２０ｄ……回転軸 ２３０……両面印刷用搬送路 ２４０……ハウジング ２５０……軸受 ２６０……加圧レバー ２７０……加圧スプリング ２８０……駆動ギヤ ２９０……支持軸 ３００……支持軸 ３１０……剥離部材 ３１０ａ……剥離部 ３１０ｂ……折曲部
３１０ｃ……支持片 ３１０ｄ……嵌合穴 ３１０ｅ……ガイド部 ３１０ｆ……先端部 ３２０……剥離部材 ３２０ａ……剥離部 ３２０ｅ……ガイド部
３３０……スプリング ３４０……定着ニップ部（ニップ部） ３４１……ニップ出口 ５００……記録媒体 Ｔ……トナー Ｓ……接線 Ｇ１……ギャップ
Ｇ２……ギャップ[0001]
BACKGROUND OF THE INVENTION
  The present inventionToner production methodIt is about.
[0002]
[Prior art]
A number of methods are known as electrophotographic methods. In general, a process (exposure process) of forming an electrical latent image on a photoconductor by various means using a photoconductive substance, A development step of developing the latent image with toner, a transfer step of transferring the toner image onto a transfer material (recording medium) such as paper, and a fixing step of fixing the toner image by heating using a fixing roller, etc. have.
[0003]
The toner used in the electrophotographic method as described above is generally composed of a material containing a resin as a main component (hereinafter also simply referred to as “resin”) and a colorant.
A polyester resin is widely used as the resin constituting the toner. The polyester resin has a feature that it can easily control properties such as an elastic modulus and chargeability of the finally obtained toner.
[0004]
In such a toner, an aromatic diol such as bisphenol A has generally been used as a diol component constituting the polyester resin (see, for example, Patent Document 1).
However, polyesters composed of such diol components have a relatively high coefficient of friction and are vulnerable to mechanical stress, so that they are liable to cause particle destruction in the developing machine and the like. There was a problem that could occur.
[0005]
There is also known a toner using a polyester composed of an aliphatic diol without using an aromatic diol such as bisphenol A (see, for example, Patent Document 2). This uses a polyester block copolymer having, as a polyester resin, a block formed by condensing an aliphatic diol and a carboxylic acid and a polyester block formed by condensing an alicyclic diol and a carboxylic acid in the molecule. Is. However, such a toner has a problem that a temperature range in which sufficient fixability (fixing strength) can be secured becomes narrow.
[0006]
[Patent Document 1]
JP 57-109825 A (page 1, lines 1 to 27)
[Patent Document 2]
JP 2001-324832 A (page 2, lines 1 to 13)
[0007]
[Problems to be solved by the invention]
An object of the present invention is to provide a toner that is excellent in durability and exhibits sufficient fixability (fixing strength) in a wide temperature range, and also provides a toner manufacturing method capable of manufacturing the toner. There is.
[0008]
[Means for Solving the Problems]
  Such an object is achieved by the present invention described below.
[0034]
  The method for producing a toner of the present invention is a method for producing a toner composed of a material containing a polyester resin and a colorant,
  The polyester resin includes a block polyester mainly composed of a block copolymer, and an amorphous polyester having lower crystallinity than the block polyester.
  The block polyester has a crystalline block formed by condensing an alcohol component and a carboxylic acid component, and an amorphous block having lower crystallinity than the crystalline block,
  A first kneading step for producing a first kneaded product containing the amorphous polyester and the colorant;
  A second kneading step for producing a second kneaded material by kneading at least the material containing the first kneaded material and the block polyester.And
The softening point of the amorphous polyester is T _1/2 (A) [° C.], the melting point of the block polyester is T _m (B) [° C.], the material temperature during the second kneading step is T _K2 [℃], T _m (B)> T _K2 > T _1/2 Satisfies the relationship (A)It is characterized by doing.
  As a result, it is possible to provide a toner that has excellent durability and exhibits sufficient fixability (fixing strength) in a wide temperature range.Also,A first region composed primarily of block polyester and primarily amorphous polyesterPhase separation (micro-separation) to an appropriate size, and the colorant contained in the first kneaded material migrates into the first region. Can be effectively prevented. As a result, the obtained toner can have particularly excellent fixability and durability in a wide temperature range.
[0035]
  The method for producing a toner of the present invention is a method for producing a toner composed of a material containing a polyester resin and a colorant,
  The polyester resin includes a block polyester mainly composed of a block copolymer, and an amorphous polyester having lower crystallinity than the block polyester.
  The block polyester has a crystalline block formed by condensing an alcohol component and a carboxylic acid component, and an amorphous block having lower crystallinity than the crystalline block,
  A first kneading step for producing a first kneaded product containing the amorphous polyester and the colorant;
  At least a second kneading step for producing a second kneaded material by kneading a material containing the first kneaded material and the block polyester;
The softening point of the amorphous polyester is T _1/2 (A) [° C.], the melting point of the block polyester is T _m (B) [° C.], the material temperature during the second kneading step is T _K2 [℃], T _m (B)> T _K2 > T _1/2 Satisfy the relationship (A),
  Forming a first region mainly composed of the block polyester and a second region mainly composed of the amorphous polyester;
  A toner is produced in which the concentration of the colorant in the second region is higher than the concentration of the colorant in the first region.
  As a result, it is possible to provide a toner that has excellent durability and exhibits sufficient fixability (fixing strength) in a wide temperature range.Also,A first region composed primarily of block polyester and primarily amorphous polyesterPhase separation (micro-separation) to an appropriate size, and the colorant contained in the first kneaded material migrates into the first region. Can be effectively prevented. As a result, the obtained toner can have particularly excellent fixability and durability in a wide temperature range.
[0036]
In the method for producing a toner of the present invention, the material temperature during the first kneading step is preferably 80 to 160 ° C.
Thereby, the 1st kneaded material in which each component was mixed uniformly can be obtained, fully preventing thermal decomposition, oxidation degradation, etc. of a material.
In the method for producing a toner of the present invention, the material temperature during the second kneading step is preferably 80 to 260 ° C.
As a result, the first region mainly composed of block polyester and the second region mainly composed of amorphous polyester can be sufficiently uniformly finely dispersed (microphase separation). Can be made particularly excellent.
[0037]
In the method for producing a toner of the present invention, it is preferable that the first kneading step and the second kneading step are continuously performed.
As a result, the manufacturing process can be simplified, and the toner productivity is improved. In addition, it is possible to more effectively prevent the deterioration of the constituent components of the toner, and the reliability of the toner is further improved.
[0038]
In the toner manufacturing method of the present invention, a two-stage barrel type kneader having a first kneading section for performing the first kneading step and a second kneading section for performing the second kneading step is used. Is preferred.
As a result, the manufacturing process can be simplified, and the toner productivity is improved. In addition, it is possible to more effectively prevent the deterioration of the constituent components of the toner, and the reliability of the toner is further improved.
[0040]
In the method for producing a toner of the present invention, a step of pulverizing and classifying the second kneaded product to obtain a toner production powder;
It is preferable to include a thermal spheronization step in which the toner manufacturing powder is heated to be spheroidized.
As a result, the variation in particle diameter among the toner particles can be made particularly small, and the circularity of the toner particles can be easily and reliably controlled within a suitable range.
In the toner manufacturing method of the present invention, the temperature of the atmosphere during the thermal spheronization step is preferably 210 to 320 ° C.
As a result, it is possible to easily and reliably control the circularity of the toner particles to a value within a suitable range while suitably preventing thermal decomposition and oxidation deterioration of the constituent components.
[0041]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a toner and a toner production method of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a longitudinal sectional view schematically showing an example of the configuration of a kneader and a cooler used in the first embodiment of the toner production method of the present invention, and FIG. 2 is a differential scanning calorimetric analysis of the block polyester. 3 is a model diagram of a differential scanning calorimetry curve near the melting point of a block polyester, FIG. 3 is a flowchart for softening point analysis, and FIG. 4 is an oxidation of rutile-anatase type liberated from toner particles contained in the toner. It is a figure for demonstrating the method to measure the quantity of titanium. Hereinafter, in FIG. 1, the left side is assumed to be “base end” and the right side is assumed to be “tip”.
[0042]
[Constituent materials]
First, constituent materials of the toner of the present invention will be described. The toner of the present invention contains at least a polyester resin as a resin component (hereinafter also simply referred to as “resin”) and a colorant.
Hereinafter, each component contained in the toner of the present invention will be described.
1. Resin (binder resin)
In the present invention, the resin (binder resin) is mainly composed of a polyester resin. The content of the polyester resin in the resin is preferably 50 wt% or more, and more preferably 80 wt% or more.
The polyester resin contains at least a block polyester as described below and an amorphous polyester. As described above, the present invention is characterized in that a block polyester and an amorphous polyester are used in combination.
[0043]
1-1. Block polyester
The block polyester is composed of a block copolymer having a crystalline block obtained by condensing an alcohol component and a carboxylic acid component, and an amorphous block having lower crystallinity than the crystalline block.
(1) Crystalline block
The crystalline block has higher crystallinity than the amorphous block or the amorphous polyester. That is, the molecular arrangement structure is stronger and more stable than amorphous blocks and amorphous polyesters. For this reason, the crystalline block contributes to improving the strength of the entire toner. As a result, the finally obtained toner is resistant to mechanical stress and has excellent durability and storage stability.
[0044]
By the way, generally resin with high crystallinity has what is called sharp melt property compared with resin with low crystallinity. That is, a resin having high crystallinity has a property that when the endothermic peak of the melting point is measured by differential scanning calorimetry (DSC), the endothermic peak appears as a sharp shape compared to the resin having low crystallinity. Yes.
On the other hand, the crystalline block has high crystallinity as described above. Accordingly, the crystalline block has a function of imparting sharp melt properties to the block polyester. For this reason, the toner of the present invention has excellent shape stability (durability) even at a relatively high temperature (temperature near the melting point of the block polyester) at which the amorphous polyester described later is sufficiently softened. Can be held. Therefore, the toner of the present invention can exhibit sufficient fixability (fixing strength) in a wide temperature range.
In addition, since the block polyester has such a crystalline block, in the present invention, the thermal spheronization treatment described later can be performed efficiently (in a short time), and finally, easily and finally. The circularity of the toner particles obtained can be made relatively high.
[0045]
Hereinafter, components constituting the crystalline block will be described.
As the alcohol component constituting the crystalline block, those having two or more hydroxyl groups can be used, and among them, an alcohol component having two hydroxyl groups is preferable. Examples of the alcohol component having two hydroxyl groups include aromatic diols having an aromatic ring structure and aliphatic diols having no aromatic ring structure. Examples of the aromatic diol include bisphenol A and alkylene oxide adducts of bisphenol A (for example, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3). ) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene ( 2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, etc.), and the aliphatic diol. Is, for example, ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3- Lopylene glycol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butane Diol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentane Diol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentane Diol, polyethylene glycol, polypropylene glycol, polytetramethylene Chain diols such as recall, or 2,2-bis (4-hydroxycyclohexyl) propane, alkylene oxide adducts of 2,2-bis (4-hydroxycyclohexyl) propane, 1,4-cyclohexanediol, 1,4 -Cyclohexane dimethanol, hydrogenated bisphenol A, cyclic diols such as hydrogenated bisphenol A alkylene oxide adducts, and the like.
[0046]
Examples of the alcohol component having three or more hydroxyl groups include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4- Butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethyl Examples include benzene.
[0047]
Thus, the alcohol component constituting the crystalline block is not particularly limited, but at least a part thereof is preferably an aliphatic diol, more preferably 80 mol% or more is an aliphatic diol, and 90 mol thereof. More preferably, at least% is an aliphatic diol. Thereby, the crystallinity of the block polyester (crystalline block) can be made particularly high, and the above-described effects become even more remarkable.
[0048]
The alcohol component constituting the crystalline block has a linear molecular structure having 3 to 7 carbon atoms and has hydroxyl groups at both ends (general formula: HO— (CH₂)_nIt is preferable to include a diol represented by —OH (where n = 3 to 7). By including such an alcohol component, the crystallinity is improved and the friction coefficient is lowered, so that it is resistant to mechanical stress and particularly excellent in durability and storage stability. Examples of such diols include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and the like, among which 1,4-butanediol Is preferred. By including 1,4-butanediol, the above-described effects become particularly remarkable.
[0049]
When 1,4-butanediol is included as the alcohol component constituting the crystalline block, 50 mol% or more of the alcohol component constituting the crystalline block is more preferably 1,4-butanediol, and 80 mol% or more thereof. More preferably, it is 1,4-butanediol. Thereby, the effect mentioned above becomes further remarkable.
[0050]
As the carboxylic acid component constituting the crystalline block, a divalent or higher carboxylic acid or a derivative thereof (for example, an acid anhydride, a lower alkyl ester, etc.) can be used. Is preferably used. Examples of such divalent carboxylic acid components include o-phthalic acid (phthalic acid), terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octyl succinic acid, cyclohexanedicarboxylic acid, fumaric acid. Examples include acids, maleic acid, itaconic acid, and derivatives thereof (for example, anhydrides, lower alkyl esters, etc.).
Examples of the trivalent or higher carboxylic acid component include trimellitic acid, pyromellitic acid, and derivatives thereof (for example, anhydride, lower alkyl ester, and the like).
[0051]
As described above, the carboxylic acid component constituting the crystalline block is not particularly limited, but at least a part thereof preferably has a terephthalic acid skeleton, and 50 mol% or more thereof has a terephthalic acid skeleton. It is more preferable that 80 mol% or more of them has a terephthalic acid skeleton. Thereby, the finally obtained toner has a particularly excellent balance of various characteristics required for the toner. However, the “carboxylic acid component” here refers to the carboxylic acid component when the block polyester is used, and when adjusting the block polyester (forming a crystalline block), the carboxylic acid component itself, Derivatives such as acid anhydrides and lower alkyl esters can be used.
[0052]
Although the content rate of the crystalline block in block polyester is not specifically limited, It is preferable that it is 5-60 mol%, and it is more preferable that it is 10-40 mol%. If the content of the crystalline block is less than the lower limit, the effect of having the crystalline block as described above may not be sufficiently exhibited depending on the content of the block polyester. On the other hand, if the content of the crystalline block exceeds the above upper limit, the content of the amorphous block is relatively lowered, so that the affinity between the block polyester and the amorphous polyester described later is reduced. There is a possibility that the first region to be coarsened.
The crystalline block may contain components other than the alcohol component and carboxylic acid component as described above.
[0053]
(2) Amorphous block
The amorphous block has lower crystallinity than the above-described crystalline block. Further, the amorphous polyester described later also has lower crystallinity than the crystalline block. That is, the amorphous block has a lower crystallinity than the crystalline block, as with the amorphous polyester described later.
By the way, in a blend resin, resins having greatly different crystallinities generally have low affinity, and phase separation (particularly macrophase separation) is easy, and resins having a small difference in crystallinity have high affinity and are easily mixed with each other. . On the other hand, as described above, the block polyester used in the present invention has a crystalline block and an amorphous block. That is, the block polyester has an amorphous block having a high affinity with the amorphous polyester and a crystalline block having a low affinity. For this reason, in the present invention, the block polyester and the amorphous polyester are likely to cause appropriate phase separation (microphase separation) while being sufficiently uniformly mixed. As a result, macro phase separation (for example, phase separation in which the average particle diameter of each phase is 1 μm or more) can be effectively prevented in the toner particles. And the advantages of amorphous polyester can be sufficiently and stably exhibited.
[0054]
Hereinafter, the components constituting the amorphous block will be described.
As the alcohol component constituting the amorphous block, those having two or more hydroxyl groups can be used, and among them, an alcohol component having two hydroxyl groups is preferable. Examples of the alcohol component having two hydroxyl groups include aromatic diols having an aromatic ring structure and aliphatic diols having no aromatic ring structure. Examples of the aromatic diol include bisphenol A and alkylene oxide adducts of bisphenol A (for example, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3). ) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene ( 2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, etc.), and the aliphatic diol. Is, for example, ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3- Lopylene glycol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butane Diol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentane Diol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentane Diol, polyethylene glycol, polypropylene glycol, polytetramethylene Chain diols such as recall, or 2,2-bis (4-hydroxycyclohexyl) propane, alkylene oxide adducts of 2,2-bis (4-hydroxycyclohexyl) propane, 1,4-cyclohexanediol, 1,4 -Cyclohexane dimethanol, hydrogenated bisphenol A, cyclic diols such as hydrogenated bisphenol A alkylene oxide adducts, and the like.
[0055]
Examples of the alcohol component having three or more hydroxyl groups include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4- Butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethyl Examples include benzene.
[0056]
Thus, although the alcohol component which comprises an amorphous block is not specifically limited, It is preferable that at least one part is an aliphatic diol, and it is more preferable that 50 mol% or more is an aliphatic diol. Thereby, an effect that a fixed image having better toughness (excellent bending resistance) can be obtained can be obtained.
Moreover, it is preferable that at least a part of the alcohol component constituting the amorphous block has a branched chain (side chain), and more preferably 30 mol% or more thereof has a branched chain. Thereby, the effect of suppressing regular arrangement, reducing crystallinity, and improving transparency is obtained.
[0057]
As the carboxylic acid component constituting the amorphous block, a divalent or higher carboxylic acid or a derivative thereof (for example, an acid anhydride, a lower alkyl ester, etc.) can be used. Etc. are preferably used. Examples of such divalent carboxylic acid components include o-phthalic acid (phthalic acid), terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octyl succinic acid, cyclohexanedicarboxylic acid, fumaric acid. Examples include acids, maleic acid, itaconic acid, and derivatives thereof (for example, anhydrides, lower alkyl esters, etc.).
Examples of the trivalent or higher carboxylic acid component include trimellitic acid, pyromellitic acid, and derivatives thereof (for example, anhydride, lower alkyl ester, and the like).
[0058]
As described above, the carboxylic acid component constituting the amorphous block is not particularly limited, but at least a part thereof preferably has a terephthalic acid skeleton, and 80 mol% or more thereof has a terephthalic acid skeleton. More preferably. Thereby, the finally obtained toner has a particularly excellent balance of various characteristics required for the toner. However, the “carboxylic acid component” here refers to the carboxylic acid component when the block polyester is used, and when preparing the block polyester (forming an amorphous block), the carboxylic acid component itself or In addition, derivatives such as acid anhydrides and lower alkyl esters thereof can be used.
The amorphous block may contain components other than the alcohol component and carboxylic acid component as described above.
[0059]
The average molecular weight (weight average molecular weight) Mw of the block polyester having the crystalline block and the amorphous block as described above is not particularly limited, but is 1 × 10.⁴~ 3x10⁵Preferably, 1.2 × 10⁴~ 1.5 × 10⁵It is more preferable that If the average molecular weight Mw is less than the lower limit, the mechanical strength of the finally obtained toner is lowered, and sufficient durability (storability) may not be obtained. On the other hand, if the average molecular weight Mw is too small, cohesive failure is likely to occur at the time of fixing the toner, and the offset resistance tends to decrease. On the other hand, when the average molecular weight Mw exceeds the upper limit, grain boundary breakage is likely to occur during toner fixing, the wettability to a transfer material (recording medium) such as paper also decreases, and the amount of heat required for fixing increases.
[0060]
Glass transition point T of block polyester_gAlthough it is not specifically limited, It is preferable that it is 50-75 degreeC, and it is more preferable that it is 55-70 degreeC. When the glass transition point is less than the lower limit, the storage stability (heat resistance) of the toner is lowered, and fusion between toner particles may occur depending on the use environment or the like. On the other hand, when the glass transition point exceeds the upper limit, low-temperature fixability and transparency are deteriorated. On the other hand, if the glass transition point is too high, the effect may not be sufficiently exhibited when a thermal spheronization treatment as described later is performed. The glass transition point can be measured according to JIS K7121.
[0061]
Softening point T of block polyester_1/2Although it is not specifically limited, It is preferable that it is 90-160 degreeC, and it is more preferable that it is 100-150 degreeC. When the softening point is less than the lower limit, the storage stability as a toner is lowered and sufficient durability may not be obtained. On the other hand, if the softening point is too low, cohesive failure is likely to occur at the time of fixing the toner, and the offset resistance tends to decrease. On the other hand, if the softening point exceeds the upper limit, grain boundary breakage is likely to occur during toner fixing, the wettability to a transfer material (recording medium) such as paper also decreases, and the amount of heat required for fixing increases. Softening point T_1/2For example, using a flow tester, sample amount: 1 g, die hole diameter: 1 mm, die length: 1 mm, load: 20 kgf, preheating time: 300 seconds, measurement start temperature: 50 ° C., heating rate: 5 ° C./min The temperature of the point on the flow curve corresponding to h / 2 in the flowchart for analysis shown in FIG.
[0062]
Melting point T of block polyester_m(Center value T of peak when endothermic peak of melting point is measured by differential scanning calorimetry described later._mp) Is not particularly limited, but is preferably 190 ° C. or higher, more preferably 190 to 230 ° C. When the melting point is less than 190 ° C., there is a possibility that effects such as improvement in offset resistance cannot be sufficiently obtained. On the other hand, if the melting point is too high, the material temperature must be relatively high in the kneading step described later. As a result, the transesterification reaction of the resin material tends to proceed, and it may be difficult to sufficiently reflect the resin design in the finally obtained toner. In addition, melting | fusing point can be calculated | required by the measurement of the endothermic peak by differential scanning calorimetry (DSC), for example.
[0063]
In addition, when the finally obtained toner is used in a fixing device having a fixing roller as described later, the melting point of the block polyester (when the endothermic peak of the melting point is measured by differential scanning calorimetry described later) Center value T of the peak_mp) T_m(B) [° C], the standard set temperature of the surface of the fixing roller is T_fix[℃], T_fix≦ T_m(B) ≤ (T_fix+100) is preferably satisfied, and (T_fix+10) ≦ T_m(B) ≤ (T_fixIt is more preferable to satisfy the relationship +70). By using a block polyester having a melting point in such a range, it is possible to effectively prevent toner from adhering to a fixing roller of a fixing device described later. In addition, since the block polyester has a property that it is easy to form crystals of an appropriate size as will be described later, stability and durability can be maintained even after the toner is fixed on the recording medium. In particular, in the present invention, since the block polyester is used in combination with the amorphous polyester described later, even if the block polyester having the melting point in the temperature range as described above is included, the amorphous polyester described later is used at the time of fixing. It can be sufficiently softened. For this reason, the fixability (fixing strength) of the toner to the recording medium can be sufficiently increased, and the low-temperature fixability of the toner is excellent. Further, since the block polyester is easy to form high hardness crystals, the toner is excellent in stability after fixing.
[0064]
Moreover, it is preferable that melting | fusing point of block polyester is higher than the softening point of the amorphous polyester mentioned later. Thereby, the stability of the shape of the toner finally obtained is improved, and particularly excellent stability (durability) against mechanical stress is exhibited. In addition, when the melting point of the block polyester is higher than the softening point of the amorphous polyester described later, for example, when the thermal spheronization process described later is performed, the shape of the powder for toner production is secured to some extent by the block polyester. However, the amorphous polyester can be sufficiently softened. As a result, the thermal spheronization treatment can be performed efficiently, and the circularity of the finally obtained toner (toner particles) can be made relatively easy.
[0065]
By the way, as described above, the block polyester used in the present invention has a crystalline block with high crystallinity, and therefore, compared with a resin material with relatively low crystallinity (for example, amorphous polyester described later). Thus, it has a so-called sharp melt property.
As an index representing crystallinity, for example, the center value of the peak when the endothermic peak of the melting point is measured by differential scanning calorimetry (DSC) is T_mp[° C], shoulder peak value is T_msWhen [° C.], ΔT = T_mp-T_msΔT value represented by (see FIG. 2). The smaller this ΔT value, the higher the crystallinity.
The ΔT value of the block polyester is preferably 50 ° C. or less, and more preferably 20 ° C. or less. T_mp[° C], T_msThe measurement conditions of [° C.] are not particularly limited. For example, after the block polyester as a sample is heated to 200 ° C. at a rate of temperature increase: 10 ° C./min, and further, the temperature is decreased at a rate of temperature decrease: 10 ° C./min. Temperature rising rate: It can be measured by increasing the temperature at 10 ° C./min.
Moreover, block polyester has higher crystallinity than the amorphous polyester mentioned later. Therefore, the ΔT value of the amorphous polyester is expressed as ΔT._A[℃], the ΔT value of the block polyester is ΔT_B[T], ΔT_A> ΔT_BSatisfy the relationship. In particular, in the present invention, ΔT_A-ΔT_BIt is preferable that the relationship> 10 is satisfied, and ΔT_A-ΔT_BIt is more preferable to satisfy the relationship> 30. By satisfying such a relationship, the above-described effect becomes more remarkable. However, when the amorphous polyester has particularly low crystallinity, T_mpOr T_msAt least one of them may be difficult to measure (difficult to distinguish). In such a case, ΔT_AIs ∞ [° C].
[0066]
The block polyester has a heat of fusion E required when the endothermic peak of the melting point is measured by differential scanning calorimetry._fIs preferably 5 mJ / mg or more, and more preferably 15 mJ / mg or more. Heat of fusion E_fIf it is less than 5 mJ / mg, there is a possibility that the effects as described above due to having the crystalline block are not sufficiently exhibited. However, the heat of fusion does not include the heat quantity of the endothermic peak at the glass transition point (see FIG. 2). The measurement conditions for the endothermic peak of the melting point are not particularly limited. For example, the block polyester as a sample was heated to 200 ° C. at a rate of temperature increase: 10 ° C./min, and further decreased at a rate of temperature decrease: 10 ° C./min. Thereafter, the value measured when the temperature is raised at a rate of temperature rise of 10 ° C./min can be determined as the heat of fusion.
[0067]
Moreover, it is preferable that block polyester is a linear type polymer (polymer which does not have a crosslinked structure). The linear polymer has a smaller coefficient of friction than the cross-linked polymer. As a result, particularly excellent releasability is obtained, and toner transfer efficiency is further improved.
In addition, block polyester may have blocks other than the crystalline block mentioned above and an amorphous block.
[0068]
1-2. Amorphous polyester
Amorphous polyester has lower crystallinity than the block polyester described above.
Amorphous polyester is a main component of the second region, which will be described in detail later, and is preferably a material excellent in dispersibility of the colorant.
[0069]
Amorphous polyester is mainly used for the pulverization of the kneaded product during toner production, toner fixability (especially, low-temperature fixability), transparency, mechanical properties (for example, elasticity, mechanical strength, etc.), and chargeability. It is a component that contributes to improving functions such as moisture resistance. In other words, if the amorphous polyester as described in detail below is not contained in the toner, it is difficult to sufficiently exhibit the characteristics required for the toner as described above.
[0070]
Hereinafter, the components constituting the amorphous polyester will be described.
As the alcohol component constituting the amorphous polyester, those having two or more hydroxyl groups can be used, and among them, an alcohol component having two hydroxyl groups is preferable. Examples of the alcohol component having two hydroxyl groups include aromatic diols having an aromatic ring structure and aliphatic diols having no aromatic ring structure. Examples of the aromatic diol include bisphenol A and alkylene oxide adducts of bisphenol A (for example, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3). ) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene ( 2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, etc.), and the aliphatic diol. Is, for example, ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3- Lopylene glycol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butane Diol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentane Diol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentane Diol, polyethylene glycol, polypropylene glycol, polytetramethylene Chain diols such as recall, or 2,2-bis (4-hydroxycyclohexyl) propane, alkylene oxide adducts of 2,2-bis (4-hydroxycyclohexyl) propane, 1,4-cyclohexanediol, 1,4 -Cyclohexane dimethanol, hydrogenated bisphenol A, cyclic diols such as hydrogenated bisphenol A alkylene oxide adducts, and the like.
[0071]
Examples of the alcohol component having three or more hydroxyl groups include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4- Butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethyl Examples include benzene.
[0072]
As the carboxylic acid component constituting the amorphous polyester, divalent or higher carboxylic acids or derivatives thereof (for example, acid anhydrides, lower alkyl esters, etc.) can be used. Etc. are preferably used. Examples of such divalent carboxylic acid components include o-phthalic acid (phthalic acid), terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octyl succinic acid, cyclohexanedicarboxylic acid, fumaric acid. Examples include acids, maleic acid, itaconic acid, and derivatives thereof (for example, anhydrides, lower alkyl esters, etc.).
Examples of the trivalent or higher carboxylic acid component include trimellitic acid, pyromellitic acid, and derivatives thereof (for example, anhydride, lower alkyl ester, and the like).
[0073]
Thus, the carboxylic acid component constituting the amorphous polyester is not particularly limited, but at least a part thereof preferably has a terephthalic acid skeleton, and 80 mol% or more thereof has a terephthalic acid skeleton. More preferably, 90 mol% or more of them has a terephthalic acid skeleton. Thereby, the finally obtained toner has a particularly excellent balance of various characteristics required for the toner. However, the “carboxylic acid component” here refers to the carboxylic acid component when the amorphous polyester is used. When preparing the amorphous polyester, the carboxylic acid component itself or its acid anhydride is used. In addition, a derivative such as a lower alkyl ester can be used.
[0074]
Moreover, it is preferable that 50 mol% or more (more preferably 80 mol% or more) of the monomer component constituting the amorphous polyester is the same as the monomer component constituting the amorphous block described above. That is, the amorphous polyester is preferably composed of the same monomer component as that of the amorphous block. As a result, the affinity between the amorphous polyester and the block polyester is particularly excellent, and the occurrence of macrophase separation in the toner particles (toner base particles) can be more effectively prevented. However, the “monomer component” here does not refer to a monomer used for producing an amorphous polyester or block polyester, but refers to a monomer component contained in the amorphous polyester or block polyester.
In addition, amorphous polyester may contain components other than the above alcohol components and carboxylic acid components.
[0075]
The average molecular weight (weight average molecular weight) Mw of the amorphous polyester is not particularly limited, but is 5 × 10.³~ 4x10⁴Preferably 8 × 10³~ 2.5 × 10⁴It is more preferable that If the average molecular weight Mw is less than the lower limit, the mechanical strength of the finally obtained toner is lowered, and sufficient durability (storability) may not be obtained. On the other hand, if the average molecular weight Mw is too small, cohesive failure is likely to occur at the time of fixing the toner, and the offset resistance tends to decrease. On the other hand, when the average molecular weight Mw exceeds the upper limit, grain boundary breakage is likely to occur during toner fixing, the wettability to a transfer material (recording medium) such as paper also decreases, and the amount of heat required for fixing increases.
[0076]
Glass transition point T of amorphous polyester_gAlthough it is not specifically limited, It is preferable that it is 50-75 degreeC, and it is more preferable that it is 55-70 degreeC. When the glass transition point is less than the lower limit, the storage stability (heat resistance) of the toner is lowered, and fusion between toner particles may occur depending on the use environment or the like. On the other hand, when the glass transition point exceeds the upper limit, low-temperature fixability and transparency are deteriorated. On the other hand, if the glass transition point is too high, the effect may not be sufficiently exhibited when a thermal spheronization treatment as described later is performed. The glass transition point can be measured according to JIS K7121.
[0077]
Softening point T of amorphous polyester_1/2Although it is not specifically limited, It is preferable that it is 90-160 degreeC, It is more preferable that it is 100-150 degreeC, It is further more preferable that it is 100-130 degreeC. When the softening point is less than the lower limit, the storage stability as a toner is lowered and sufficient durability may not be obtained. On the other hand, if the softening point is too low, cohesive failure is likely to occur at the time of fixing the toner, and the offset resistance tends to decrease. On the other hand, if the softening point exceeds the upper limit, grain boundary breakage is likely to occur during toner fixing, the wettability to a transfer material (recording medium) such as paper also decreases, and the amount of heat required for fixing increases.
[0078]
In addition, the softening point of amorphous polyester is T_1/2(A) [° C], the melting point of the block polyester described above is T_mWhen (B), T_m(B)> (T_1/2It is preferable to satisfy the relationship (A) +60), and (T_1/2(A) +60) <T_m(B) <(T_1/2It is more preferable to satisfy the relationship (A) +150). By satisfying such a relationship, for example, at a relatively high temperature, the amorphous polyester can be sufficiently softened while the block polyester ensures the stability of the shape of the toner particles to some extent. As a result, it is possible to achieve excellent fixability in a wide temperature range (particularly fixability in a low temperature range) while sufficiently ensuring the stability of the shape of the toner. Further, by satisfying the above relationship, for example, the thermal spheronization process described later can be performed more efficiently, and the circularity of the toner (particles) obtained can be further improved. Further, by satisfying the relationship as described above, the toner can exhibit excellent fixability in a wider temperature range.
[0079]
Softening point T_1/2For example, using a flow tester, sample amount: 1 g, die hole diameter: 1 mm, die length: 1 mm, load: 20 kgf, preheating time: 300 seconds, measurement start temperature: 50 ° C., heating rate: 5 ° C./min The temperature of the point on the flow curve corresponding to h / 2 in the flowchart for analysis shown in FIG.
The amorphous polyester is preferably a linear polymer (a polymer having no cross-linked structure). The linear polymer has a smaller coefficient of friction than the cross-linked polymer. Thereby, particularly excellent releasability is obtained, and the transfer efficiency of the toner is further improved.
[0080]
As described above, the present invention is characterized in that block polyester and amorphous polyester are used in combination. Thus, the combined use of the block polyester and the amorphous polyester makes it possible to achieve both the characteristics of the block polyester and the characteristics of the amorphous polyester as described above. As a result, the finally obtained toner is excellent in durability (strong against mechanical stress) and can exhibit sufficient fixing properties (fixing strength) in a wide temperature range. Further, at the time of toner production, the pulverizability of the obtained kneaded product becomes good, and the toner productivity is improved.
[0081]
The synergistic effect as described above cannot be obtained when only one of the block polyester and the amorphous polyester is used.
That is, when only the block polyester is used (when the amorphous polyester is not included in the toner), the toner fixability (particularly, the fixability in a low temperature region) is lowered. In addition, when only block polyester is used (when the amorphous polyester is not included in the toner), for example, it becomes difficult to sufficiently reduce the viscosity of the toner particles when fixing the toner. Fixability to a medium (fixing strength) decreases. Further, when only the block polyester is used (when the amorphous polyester is not included in the toner), functions such as transparency of the toner are lowered, and each component constituting the toner (for example, as described later) The dispersibility of the colorant, wax, antistatic agent, etc.) and the pulverizability of the kneaded product during toner production are also reduced.
In addition, when only amorphous polyester is used (when the block polyester is not included in the toner), the final toner is weak against mechanical stress, and sufficient durability and storage stability are obtained. I can't. In addition, when only amorphous polyester is used (when the block polyester is not included in the toner), a sharp melt property cannot be obtained, so sufficient fixability (fixing strength) in a wide temperature range (especially in a high temperature range). ) Is difficult to ensure, and, for example, when performing a thermal spheronization process, which will be described later, it is difficult to perform efficiently, and the circularity of the finally obtained toner particles is set to an appropriate value. It becomes difficult.
[0082]
By the way, polyester having high crystallinity (hereinafter referred to as “crystalline polyester”) generally has a stable molecular arrangement structure, so that the strength as a toner is improved even if it is not a block polyester as described above. It can be made strong against mechanical stress. However, crystalline polyesters other than the block polyester described above are inferior in affinity with amorphous polyester, and when used in combination with amorphous polyester, macrophase separation is likely to occur. Therefore, when the crystalline polyester other than the block polyester and the amorphous polyester are used in combination without using the block polyester, the synergistic effect of using the block polyester and the amorphous polyester as described above. There is no effect.
[0083]
The blending ratio of the block polyester and the amorphous polyester is preferably 5:95 to 45:55, more preferably 10:90 to 30:70, by weight. If the blending ratio of the block polyester becomes too low, it may be difficult to sufficiently improve the offset resistance of the toner. On the other hand, if the blending ratio of the amorphous polyester is too low, sufficient low-temperature fixability and transparency may not be obtained. Further, if the blending ratio of the amorphous polyester becomes too low, for example, the kneaded product (second kneaded product 10) is efficiently crushed to a uniform size in the pulverization step of the toner production method as described later. It becomes difficult to do. Further, if the blending ratio of the amorphous polyester is too low, it is difficult to efficiently disperse the colorant in the second region described later, and the effects of the present invention may not be sufficiently exhibited.
[0084]
The content of the polyester resin in the toner is not particularly limited, but is preferably 50 to 98 wt%, more preferably 85 to 97 wt%. If the content of the polyester resin is less than the lower limit, the functions (and synergistic effects) of the block polyester and amorphous polyester as described above may not be sufficiently exhibited in the finally obtained toner. There is sex. On the other hand, when the content of the polyester-based resin exceeds the upper limit, the content of components other than the resin such as the colorant is relatively lowered, and it becomes difficult to sufficiently exhibit toner characteristics such as color development. .
In addition, the resin (binder resin) may include a component (third resin component) other than the above-described block polyester and amorphous polyester.
[0085]
Examples of the resin component (third resin component) other than the block polyester and the amorphous polyester include polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, Styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene -Styrene resin such as acrylic ester-methacrylic ester copolymer, styrene-α-chloromethyl acrylate copolymer, styrene-acrylonitrile-acrylic ester copolymer, styrene-vinyl methyl ether copolymer Or containing styrene substitution Homopolymer or copolymer, polyester resin (different from the above-mentioned block polyester and amorphous polyester), epoxy resin, urethane-modified epoxy resin, silicone-modified epoxy resin, vinyl chloride resin, rosin-modified maleic acid resin, Phenyl resin, polyethylene, polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, etc. Of these, one or two or more of these can be used in combination.
[0086]
The content of the resin in the toner is not particularly limited, but is preferably 50 to 98 wt%, and more preferably 85 to 97 wt%. If the resin content is less than the lower limit, the function of the resin (for example, good fixability in a wide temperature range) may not be sufficiently exhibited in the finally obtained toner. On the other hand, when the resin content exceeds the upper limit, the content of components other than the resin such as the colorant is relatively lowered, and it becomes difficult to sufficiently exhibit toner characteristics such as color development.
[0087]
2. Colorant
Examples of the colorant that can be used include pigments and dyes.
As will be described in detail later, the toner of the present invention has a first region (phase) mainly composed of block polyester and a second region (phase) mainly composed of amorphous polyester, The colorant concentration in the second region is higher than the colorant concentration in the first region. For this reason, it is preferable to use a colorant having excellent affinity with the amorphous polyester.
[0088]
Examples of such pigments and dyes include carbon black, spirit black, lamp black (CI No. 77266), magnetite, titanium black, chrome lead, cadmium yellow, mineral fast yellow, navel yellow, and naphthol yellow S. , Hansa Yellow G, Permanent Yellow NCG, Chrome Yellow, Benzidine Yellow, Quinoline Yellow, Tartrazine Lake, Red Mouth Lead, Molybdenum Orange, Permanent Orange GTR, Pyrazolone Orange, Benzidine Orange G, Cadmium Red, Permanent Red 4R, Watching Red Calcium salt, eosin lake, brilliant carmine 3B, manganese purple, fast violet B, methyl violet lake, bitumen, cobalt blue, al Reblue Lake, Victoria Blue Lake, First Sky Blue, Indanthrene Blue BC, Ultramarine, Aniline Blue, Phthalocyanine Blue, Calco Oil Blue, Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake, Phthalocyanine Green, Final Yellow Green G, Rhodamine 6G, quinacridone, rose bengal (C.I. No. 45432), C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 184, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 5: 1, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Basic Green 6, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 180, C.I. I. Pigment Yellow 162, nigrosine dye (CI No. 50415B), metal complex dye, silica, aluminum oxide, magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, Examples thereof include metal oxides such as magnesium oxide, and magnetic materials containing magnetic metals such as Fe, Co, and Ni, and one or more of these can be used in combination.
[0089]
The content of the colorant in the toner is not particularly limited, but is preferably 1 to 10 wt%, and more preferably 3 to 8 wt%. If the content of the colorant is less than the lower limit, it may be difficult to form a visible image having a sufficient density depending on the type of the colorant. On the other hand, when the content of the colorant exceeds the upper limit, the content of the resin is relatively lowered, and the fixing property to a transfer material (recording medium) such as paper at a necessary color density is lowered.
[0090]
The size of the colorant particles is not particularly limited, but the length (average length in the longitudinal direction) is preferably 10 to 200 nm, and more preferably 20 to 100 nm. When the particle size of the colorant is in such a range, the filler effect described later becomes more remarkable, and the durability of the toner as a whole is further improved.
[0091]
3. wax
Further, the toner may contain wax as necessary.
By including the wax, for example, the releasability of the toner particles can be improved.
Examples of the wax include hydrocarbon waxes such as ozokerite, cercin, paraffin wax, microwax, microcrystalline wax, petrolatum, Fischer-Tropsch wax, carnauba wax, rice wax, methyl laurate, methyl myristate, palmitic acid. Methyl, methyl stearate, butyl stearate, candelilla wax, cotton wax, wood wax, beeswax, lanolin, montan wax, fatty acid ester ester wax, polyethylene wax, polypropylene wax, oxidized polyethylene wax, oxidized polypropylene wax Olefin waxes such as 12-hydroxy stearamide, stearamide, phthalic anhydride amide wax, Lauro , Ketone waxes such as stearone, ether waxes, and the like, can be used singly or in combination of two or more of them.
[0092]
Among the above materials, particularly when ester wax (for example, carnauba wax or rice wax) is used, the following effects can be obtained.
The ester wax has an ester structure in the molecule similarly to the polyester resin described above, and is excellent in compatibility with the polyester resin. For this reason, generation and coarsening of free wax in the finally obtained toner particles can be prevented (fine dispersion and microphase separation of the wax in the toner can be easily achieved). As a result, the finally obtained toner has particularly excellent releasability from the fixing roller.
[0093]
Moreover, as a low melting point polyester used as wax (hereinafter also referred to as “low melting point polyester”), for example, a melting point T_mIs preferably about 70 to 90 ° C. Moreover, it is preferable that the weight average molecular weight Mw of low melting point polyester is about 3500-6500. The low melting point polyester is preferably a polymer of an aliphatic monomer. If the low-melting polyester satisfies such conditions (at least one, preferably two or more), the compatibility with the above-described polyester resin is particularly excellent, and the toner release The property can be made particularly excellent.
[0094]
Melting point T of wax_mAlthough it is not specifically limited, It is preferable that it is 30-160 degreeC, and it is more preferable that it is 50-100 degreeC. Note that, for example, by differential scanning calorimetry (DSC), the temperature is increased to 200 ° C. at a rate of temperature increase of 10 ° C./min, and further the temperature is decreased at a rate of temperature decrease of 10 ° C./min, and then the rate of temperature increase is 10 ° C./min. From the measurement under the condition of increasing the temperature at_mAnd the heat of fusion.
[0095]
For example, in addition to the wax described above, a low-melting polyester (hereinafter also referred to as “low-melting polyester”) can be used as a component capable of imparting a wax effect. The low melting point is, for example, the melting point T_mIs preferably about 70 to 90 ° C. Moreover, it is preferable that the weight average molecular weight Mw of low melting point polyester is about 3500-6500. The low melting point polyester is preferably a polymer of an aliphatic monomer. If the low-melting polyester satisfies such conditions (at least one, preferably two or more), the compatibility with the above-described polyester resin is particularly excellent, and the durability of the toner is also high. The toner releasability can be imparted without inhibiting the toner. Further, since the melting point is relatively low, the low-temperature fixability can be improved.
[0096]
4). Other ingredients
The toner may contain components other than the resin, the colorant, and the wax. Examples of such components include a charge control agent, a dispersant, and magnetic powder.
[0097]
Examples of the charge control agent include benzoic acid metal salts, salicylic acid metal salts, alkyl salicylic acid metal salts, catechol metal salts, metal-containing bisazo dyes, nigrosine dyes, tetraphenylborate derivatives, quaternary ammonium salts, Examples thereof include alkyl pyridinium salts, chlorinated polyesters, and nitrofunic acid.
Examples of the dispersant include metal soaps, inorganic metal salts, organic metal salts, and polyethylene glycol.
[0098]
Examples of the metal soap include tristearic acid metal salts (for example, aluminum salts), distearic acid metal salts (for example, aluminum salts, barium salts, etc.), stearic acid metal salts (for example, calcium salts, lead salts, zinc salts, etc.) ), Linolenic acid metal salts (eg, cobalt salts, manganese salts, lead salts, zinc salts, etc.), octanoic acid metal salts (eg, aluminum salts, calcium salts, cobalt salts, etc.), oleic acid metal salts (eg, calcium salts) , Cobalt salts, etc.), palmitic acid metal salts (eg, zinc salts, etc.), naphthenic acid metal salts (eg, calcium salts, cobalt salts, manganese salts, lead salts, zinc salts, etc.), resin acid metal salts (eg, calcium Salt, cobalt salt, manganese lead salt, zinc salt, etc.).
[0099]
Examples of the inorganic metal salt and the organic metal salt include a cation of an element selected from the group consisting of metals of Group IA, Group IIA, and Group IIIA of the periodic table as a cationic component, and an anion Examples of the property component include salts containing an anion selected from the group consisting of halogen, carbonate, acetate, sulfate, borate, nitrate, and phosphate.
[0100]
Examples of the magnetic powder include magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, magnesium oxide, and other metal oxides such as Fe, Co, and Ni. The thing comprised with the magnetic material containing a magnetic metal etc. are mentioned.
In addition to the above materials, for example, zinc stearate, zinc oxide, cerium oxide, or the like may be used as an additive.
[0101]
Further, the toner of the present invention may be provided with an external additive.
Examples of the external additive include titanium oxide, silica (positively charged silica, negatively charged silica, etc.), aluminum oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, zinc oxide, alumina, magnetite, and the like. Fine particles composed of inorganic materials such as oxides, nitrides such as silicon nitride, carbides such as silicon carbide, metal salts such as calcium sulfate, calcium carbonate, and aliphatic metal salts, acrylic resins, fluororesins, polystyrene resins, polyesters Examples thereof include resins and organic metal materials such as aliphatic metal salts (for example, magnesium stearate).
Among the external additives, examples of the titanium oxide that can be used as the external additive include rutile type titanium oxide, anatase type titanium oxide, and rutile anatase type titanium oxide.
[0102]
The rutile anatase type titanium oxide has a rutile type titanium oxide (titanium dioxide) and a crystal structure anatase type titanium oxide (titanium dioxide) in the same particle. That is, the rutile anatase type titanium oxide has a mixed crystal type titanium oxide (titanium dioxide) of a rutile type crystal and an anatase type crystal.
Rutile-type titanium oxide usually has the property of easily forming spindle-shaped crystals. In addition, anatase type titanium oxide has the property of easily depositing fine crystals and being excellent in affinity with a silane coupling agent or the like used for hydrophobizing treatment or the like.
[0103]
And since rutile anatase type titanium oxide has a mixed crystal type titanium oxide of a rutile type crystal and an anatase type crystal, the advantage of the rutile type titanium oxide and the advantage of the anatase type titanium oxide And have both. That is, in the rutile-anatase type titanium oxide, a minute anatase-type crystal is mixed between the rutile-type crystals (inside the rutile-type crystal), and as a whole has a substantially spindle shape, It becomes difficult to embed in the mother particles, and the rutile-anatase-type titanium oxide as a whole has excellent affinity with silane coupling agents, etc., so that it is uniform on the surface of the rutile-anatase-type titanium oxide powder. A stable hydrophobic coating (silane coupling coating) is easily formed. Therefore, the toner obtained by containing the rutile-anatase type titanium oxide has a uniform charge distribution (the charge distribution of the toner particles is sharp), a stable charge characteristic, environmental characteristics (especially moisture resistance), and fluidity. And excellent caking resistance.
[0104]
In particular, the rutile-anatase type titanium oxide exhibits the following synergistic effect when used in combination with the polyester resin as described above.
That is, as described above, in the present invention, the polyester-based resin contains a block polyester having a crystalline block with high crystallinity. Therefore, in the toner particles, the polyester resin has a predetermined size mainly formed by the crystalline block. It can have a crystal. By having such a crystal, the rutile-anatase type titanium oxide becomes difficult to be embedded in the toner base particles. That is, by including a hard component such as the crystal, the rutile-anatase type titanium oxide is surely supported (attached) near the surface of the toner base particles. Thereby, the function of rutile-anatase-type titanium oxide (particularly, effects such as excellent fluidity and chargeability) can be sufficiently exhibited. Thus, since the function of a rutile-anatase type titanium oxide can fully be exhibited by using together with the polyester-type resin mentioned above, the quantity of the external additive to be used can be suppressed. As a result, it is possible to effectively prevent the occurrence of inconvenience (for example, a decrease in fixability to a transfer material (recording medium) such as paper) due to the addition of a large amount of external additive.
[0105]
The abundance ratio of the rutile-type titanium oxide and the anatase-type titanium oxide in the rutile-anatase-type titanium oxide is not particularly limited, but is preferably 5:95 to 95: 5 by weight, and 50:50 More preferably, it is -90: 10. By using such a rutile-anatase type titanium oxide, the effect by using the above-mentioned rutile-anatase type titanium oxide becomes more remarkable.
The rutile-anatase type titanium oxide preferably absorbs light in the wavelength region of 300 to 350 nm. As a result, the toner has excellent light resistance (particularly, light resistance after fixing on a recording medium).
[0106]
The shape of the rutile-anatase type titanium oxide used in the present invention is not particularly limited, but it is generally a spindle shape.
When the rutile-anatase type titanium oxide has a substantially spindle shape, the average major axis diameter is preferably 10 to 100 nm, and more preferably 20 to 50 nm. When the average major axis diameter is in such a range, the rutile-anatase type titanium oxide can sufficiently exhibit the functions described above, and is difficult to be embedded in the toner base particles. It becomes difficult to release. As a result, the stability of the toner against mechanical stress is further improved.
[0107]
The content of the rutile-anatase type titanium oxide in the toner is not particularly limited, but is preferably 0.1 to 2.0 wt%, and more preferably 0.5 to 1.0 wt%. If the content of the rutile-anatase type titanium oxide is less than the lower limit, the effect of using the rutile-anatase type titanium oxide as described above may not be sufficiently exhibited. On the other hand, when the content of the rutile-anatase type titanium oxide exceeds the upper limit, the fixability of the toner tends to be lowered.
[0108]
Such a rutile-anatase type titanium oxide may be prepared by any method, but can be obtained, for example, by firing anatase-type titanium oxide. By using such a method, the abundance ratio of the rutile-type titanium oxide and the anatase-type titanium oxide in the rutile-anatase-type titanium oxide can be controlled relatively easily and reliably. When obtaining a rutile-anatase type titanium oxide by such a method, it is preferable that a calcination temperature is about 700-1000 degreeC. By setting the firing temperature within this range, it is possible to more easily and reliably control the abundance ratio of rutile titanium oxide and anatase titanium oxide in rutile anatase titanium oxide. Become.
[0109]
Moreover, it is preferable that the rutile-anatase type titanium oxide is hydrophobized. By applying the hydrophobizing treatment, the effect that charging is not greatly influenced by humidity can be obtained. As the hydrophobizing treatment, for example, HMDS, a silane coupling agent (for example, one having a functional group such as an amino group), a titanate coupling agent, a fluorine-containing silane coupling agent, silicone oil or the like is used. And surface treatment of rutile-anatase type titanium oxide powder (particles).
[0110]
Among the external additives described above, examples of silica that can be used as the external additive include positively charged silica and negatively charged silica. The positively chargeable silica can be obtained, for example, by subjecting negatively chargeable silica to a surface treatment with a silane coupling agent having a functional group such as an amino group.
When negatively chargeable silica is used as the external additive, the charge amount (absolute value) of the toner particles can be increased. As a result, a stable negatively chargeable toner can be obtained, and the toner control of the image forming apparatus can be easily performed.
[0111]
Further, when negatively charged silica is used in combination with the rutile-anatase type titanium oxide described above, a particularly excellent effect is obtained. That is, by using negatively-charged silica and rutile-anatase type titanium oxide in combination, the fluidity and environmental characteristics (especially moisture resistance) of the toner can be further improved, and more stable triboelectric chargeability can be exhibited. Thus, the occurrence of so-called fog can be more effectively prevented. Further, by using negatively-charged silica and rutile-anatase type titanium oxide in combination, the obtained toner can have a large charge amount (absolute value) and a sharper charge distribution.
The average major axis diameter of the substantially spindle-shaped rutile-anatase type titanium oxide is D₁[Nm], the average particle diameter of the negatively charged silica is D₂When [nm], 0.2 ≦ D₁/ D₂It is preferable that the relationship of ≦ 15 is satisfied, and 0.4 ≦ D₁/ D₂It is more preferable to satisfy the relationship of ≦ 5. By satisfying such a relationship, the effect of using negatively charged silica and rutile-anatase type titanium oxide in combination becomes even more remarkable. In the present specification, “average particle diameter” refers to an average particle diameter based on volume.
[0112]
Further, when positively chargeable silica is used as the external additive, for example, the positively chargeable silica can function as a microcarrier, and the chargeability of the toner particles themselves can be further improved. In particular, by using the positively chargeable silica in combination with the above-described rutile-anatase type titanium oxide, the obtained toner can have a large charge amount (absolute value) and a sharper charge distribution. .
When positively chargeable silica is included, the average particle size is preferably 30 to 100 nm, and more preferably 40 to 50 nm. When the average particle diameter of the positively chargeable silica is in such a range, the above-described effect becomes more remarkable.
Further, as the external additive, HMDS, a silane coupling agent (for example, one having a functional group such as an amino group), titanate coupling agent on the surface of the fine particles composed of the above-described materials. Alternatively, a surface treated with a fluorine-containing silane coupling agent, silicone oil or the like may be used.
[0113]
[toner]
Next, the toner of the present invention composed of the above materials will be described.
As described above, the toner of the present invention contains block polyester and amorphous polyester. As described above, since the block polyester has a crystalline block with high crystallinity, the toner (toner particles) of the present invention usually contains crystals mainly composed of crystalline blocks. . The presence of such crystals makes the toner particularly excellent in durability (shape stability).
[0114]
As will be described in detail later, it is preferable that such crystals have an appropriate size. That is, if the size of the crystal is too small, the effect of having the crystal as described above may not be sufficiently exhibited. It is generally known that crystal growth is inhibited by the presence of impurities (in particular, the presence of solid impurities).
[0115]
Therefore, in the present invention, the following conditions are satisfied.
That is, the toner (toner particles) of the present invention has a first region mainly composed of block polyester and a second region mainly composed of amorphous polyester, and coloring in the second region. The concentration (content rate) of the agent was made higher than the concentration (content rate) of the colorant in the first region. By satisfying such a relationship, the content of the colorant in the first region (region mainly composed of block polyester) can be lowered. As a result, in the first region, inhibition of crystal growth due to the presence of the colorant that is an impurity can be effectively prevented and suppressed, and a crystal having an appropriate size can be formed.
[0116]
In addition, by satisfying the above relationship, the content of the colorant in the second region (a region mainly composed of amorphous polyester) can be increased. The amorphous polyester mainly constituting the second region is inherently relatively low in shape stability, but as described above, the second region contains a colorant at a relatively high concentration. As a result, the filler effect by the colorant is effectively exhibited, the stability of the shape in the second region is also improved, and the stability (durability) of the toner particles as a whole is particularly excellent.
As described above, the present invention uses a combination of a block polyester and an amorphous polyester, and further distributes a colorant in a predetermined region, so that they act synergistically and fix in a wide temperature range. It is characterized in that the durability of the toner as a whole can be made particularly excellent while sufficiently holding the toner.
[0117]
Further, the concentration (content ratio) of the colorant in the first region is C₁[Vol%], the concentration (content ratio) of the colorant in the second region is C₂When it is [vol%], 0.1 ≦ C₁/ C₂It is preferable that the relationship of ≦ 1 is satisfied, and 0.1 ≦ C₁/ C₂It is more preferable to satisfy the relationship of ≦ 0.5. By satisfying such a relationship, the above-described effect becomes more remarkable.
[0118]
In contrast, C₁/ C₂If the value is less than the lower limit, the concentration of the colorant in the second region becomes relatively high, and the above-described problem may occur. In order to avoid such a problem, if the concentration of the colorant in the second region is relatively low, the content of the colorant contained in the entire toner is reduced, and the function of the colorant as described above May not be fully utilized.
[0119]
C₁/ C₂If the value exceeds the upper limit, the concentration of the colorant in the first region becomes relatively high, and the effects as described above may not be sufficiently obtained. In order to avoid such a problem, if the concentration of the colorant in the first region is relatively low, the content of the colorant contained in the entire toner is reduced, and the function of the colorant as described above May not be fully utilized.
[0120]
Further, the first region is preferably present in a finely dispersed state in the toner particles. This makes it difficult for characteristic differences in strength and chargeability to appear between the first region and the second region, and durability and charge stability are further improved. Specifically, the size (average particle diameter) of the first region is preferably finely dispersed to 2 μm or less, and more preferably 0.05 to 1 μm. Thereby, the effect mentioned above becomes further remarkable.
[0121]
Of all the colorants contained in the toner, the proportion of the colorant contained in the first region is preferably 49 vol% or less, and more preferably 40 vol% or less. By satisfying such a condition, the above-described effects become more remarkable.
The ratio of the colorant contained in the second region out of the total colorant contained in the toner is preferably 51 to 90 vol%, and more preferably 60 to 90 vol%. By satisfying such a condition, the above-described effects become more remarkable. On the other hand, when the concentration of the colorant in the second region is less than the lower limit value, the above-described effects can be sufficiently obtained depending on the concentration of the colorant in the first region, the size of the crystal, and the like. It may not be possible. Further, when the concentration of the colorant in the second region exceeds the upper limit, the filler effect by the colorant is saturated, and it is difficult to further improve the durability. In addition, the color in the second region is colored. If the concentration of the agent becomes extremely high, the durability of the toner is rather lowered.
[0122]
The toner (toner powder) of the present invention preferably has an average circularity R represented by the following formula (I) of 0.91 to 0.98, preferably 0.93 to 0.98. More preferred. When the average circularity R is less than 0.91, it becomes difficult to sufficiently reduce the difference in charging characteristics between individual toner powders, and the developability on the photoreceptor tends to be lowered. On the other hand, if the average circularity R is too small, toner adhesion (filming) is likely to occur on the photoreceptor, and the toner transfer efficiency may decrease. On the other hand, when the average circularity R exceeds 0.98, the transfer efficiency and mechanical strength are increased, but there is a problem that the average particle diameter is increased by promoting granulation (joining of particles). If the average circularity R exceeds 0.98, for example, it becomes difficult to remove the toner adhering to the photoreceptor or the like by cleaning.
R = L₀/ L₁... (I)
(However, in the formula, L₁[Μm] is the peripheral length of the projected image of the toner particles to be measured, L₀[Μm] represents the perimeter of a perfect circle (complete geometric circle) having an area equal to the area of the projected image of the toner particles to be measured. )
[0123]
The average particle diameter of the toner is preferably 3 to 12 μm, and more preferably 5 to 10 μm. When the average particle diameter of the toner is less than the lower limit, fusion between the toner particles is likely to occur. On the other hand, when the average particle diameter of the toner exceeds the upper limit, the resolution of the printed matter tends to decrease.
Further, the content of the polyester resin in the toner is preferably 50 to 98 wt%, and more preferably 85 to 97 wt%. If the content of the polyester resin is less than the lower limit, the effect of the present invention may not be sufficiently obtained. On the other hand, when the content of the polyester-based resin exceeds the upper limit, the content of components such as a colorant may be relatively lowered, and it may be difficult to exhibit characteristics such as color developability.
[0124]
Further, when the toner contains wax, the content thereof is not particularly limited, but is preferably 5 wt% or less, more preferably 3 wt% or less, and 0.5 to 3 wt%. Further preferred. If the content of the wax is too large, the wax is liberated and coarsened, and the exudation of the wax on the toner surface may occur remarkably, making it difficult to sufficiently increase the toner transfer efficiency.
The acid value as a physical property of the toner is one of the factors that influence the environmental characteristics (particularly moisture resistance) of the toner. The acid value of the toner is preferably 8 KOH mg / g or less, and more preferably 1 KOH mg / g or less. When the acid value of the toner is 8 KOHmg / g or less, the environmental characteristics (particularly moisture resistance) of the toner are particularly excellent.
[0125]
Further, when the toner of the present invention is used in a fixing device having a nip portion as will be described later, the amount of change in relaxation elastic modulus G (t) in the passage time Δt [seconds] of the toner particles through the nip portion is: It is preferably 500 [Pa] or less, and more preferably 100 [Pa] or less. By satisfying such conditions, inconveniences such as offset are less likely to occur.
[0126]
Further, when the toner of the present invention is used in a fixing device having a fixing nip as described later, the time required for the toner particles to pass through the fixing nip is Δt [seconds], and the toner is 0.01 seconds. Where the initial relaxation elastic modulus G (0.01) is the relaxation elastic modulus of the toner and G (Δt) is the relaxation elastic modulus of the toner in Δt seconds, G (0.01) / G (Δt) ≦ It is preferable that the relationship of 10 is satisfied, and it is more preferable that the relationship of 1 ≦ G (0.01) / G (Δt) ≦ 8 is satisfied. 1 ≦ G (0.01) / G (Δt) ≦ 6 It is more preferable to satisfy this relationship. Satisfying such a relationship makes it difficult for toner to cry and offset due to a decrease in the elastic modulus of the toner particles. On the other hand, if G (0.01) / G (Δt) exceeds 10, the toners are separated and the offset is likely to occur. The relaxation elastic modulus of the toner is, for example, the composition of the constituent material of the toner (for example, the molecular weight of the block polyester and the amorphous polyester, the monomer component, the randomness, the composition of the wax and the external additive, the content of each constituent component, etc. ), The concentration (content ratio) of the colorant in the first region and the second region, toner production conditions (for example, the raw material temperature in the kneading step, the kneading time, the cooling rate of the kneaded product in the cooling step, the heat It can be adjusted by the processing temperature in the spheronization step).
[0127]
As described above, in the toner of the present invention, there are usually crystals mainly composed of crystalline blocks of block polyester.
Such crystals preferably have an average length (average length in the longitudinal direction) of 10 nm or more, more preferably 10 to 1000 nm, and even more preferably 50 to 700 nm. When the crystal length satisfies such conditions, the toner shape stability is particularly excellent, and particularly excellent stability (durability) against mechanical stress is exhibited. In particular, the external additive is more reliably held near the surface of the toner particles (toner base particles) (the external additive can be effectively prevented from being embedded in the base particles), and the toner The particles are particularly excellent in stability in a developing device or the like, and are less likely to cause filming or the like.
[0128]
In particular, when the toner contains rutile-anatase type titanium oxide, it is preferable to satisfy the following relationship. That is, the average major axis diameter of the substantially spindle-shaped rutile-anatase type titanium oxide is D₁[Nm], the average length of the crystal is L_CWhen [nm] is set, 0.01 ≦ D₁/ L_CIt is preferable that the relationship of ≦ 2 is satisfied, and 0.02 ≦ D₁/ L_CIt is more preferable to satisfy the relationship of ≦ 1. By satisfying such a relationship, the rutile-anatase type titanium oxide exhibits the above-described effects sufficiently and is difficult to be embedded in the mother particles. As a result, the toner sufficiently retains the above-described functions and is particularly excellent in stability against mechanical stress.
The average length of the crystal can be measured by a transmission electron microscope (TEM), small angle X-ray scattering measurement, or the like.
[0129]
The toner of the present invention is preferably applied to a non-magnetic one-component toner. Non-magnetic one-component toner is generally applied to an image forming apparatus having a regulating blade as described later. Therefore, the toner of the present invention that is resistant to mechanical stress can exhibit the above-described effects more remarkably when used as a non-magnetic one-component toner.
[0130]
Further, the fixing device in which the toner of the present invention is used is not particularly limited, but is preferably used in a contact-type fixing device as described later. As a result, both the advantages of high releasability from the fixing roller due to the block polyester crystals and the effect of improving the fixability (fixing strength) due to the low-viscosity amorphous polyester are fully exhibited, and a wide range of good fixing is obtained. Secured.
[0131]
Next, a fixing device and an image forming apparatus to which the toner of the present invention is preferably applied will be described.
FIG. 5 is an overall configuration diagram showing a preferred embodiment of the image forming apparatus of the present invention (an image forming apparatus to which the toner of the present invention is preferably applied), and FIG. 6 is a developing device included in the image forming apparatus of FIG. FIG. 7 shows a detailed structure of the fixing device of the present invention used in the image forming apparatus of FIG. 5, is a perspective view showing a partially broken section, and FIG. 8 is a sectional view of the main part of the fixing device of FIG. 9 is a perspective view of the peeling member constituting the fixing device of FIG. 7, FIG. 10 is a side view showing the mounting state of the peeling member constituting the fixing device of FIG. 7, and FIG. 11 is the fixing of FIG. FIG. 12 is a schematic view for explaining the arrangement angle of the peeling member with respect to the tangent at the exit of the fixing nip portion, and FIG. 13 is the shape of the fixing roller and the pressure roller, and the fixing. FIG. 14 is a diagram schematically showing the shape of the nip portion, and FIG. 15 is a diagram schematically showing the shape of the fixing roller and the pressure roller and the shape of the fixing nip portion, FIG. 16 is a cross-sectional view taken along line YY of FIG. 15A, and FIG. FIG. 6 is a cross-sectional view for explaining a gap between the fixing roller and the peeling member.
[0132]
An image carrier 30 including a photosensitive drum is disposed in the apparatus main body 20 of the image forming apparatus 1000, and is driven to rotate in a direction indicated by an arrow by a driving unit (not shown). Around the image carrier 30, an electrostatic latent image is formed on the image carrier 30, a charging device 40 for uniformly charging the image carrier (photoconductor) 30 along the rotation direction. There are provided an exposure device 50, a rotary developing device 60 for developing an electrostatic latent image, and an intermediate transfer device 70 for primary transfer of a monochromatic toner image formed on the image carrier 30.
[0133]
In the rotary developing device 60, a yellow developing device 60Y, a magenta developing device 60M, a cyan developing device 60C, and a black developing device 60K are mounted on a support frame 600, and the support frame 600 is rotationally driven by a drive motor (not shown). It is configured. The plurality of developing devices 60Y, 60C, 60M, and 60K are selectively rotated so that the developing roller 604 of one developing device faces the image carrier 30 every rotation of the image carrier 30. Has been. Each of the developing devices 60Y, 60C, 60M, and 60K has a toner storage portion that stores toner of each color.
The developing devices 60Y, 60C, 60M, and 60K all have the same structure. Therefore, although the structure of the developing device 60Y will be described here, the structures and functions of the developing devices 60C, 60M, and 60K are the same.
[0134]
As shown in FIG. 6, in the developing device 60Y, a supply roller 603 and a developing roller 604 are axially attached to a housing 601 that accommodates toner T therein, and when the developing device 60Y is positioned at the development position described above. The developing roller 604 functioning as a “toner carrier” is positioned in contact with the image carrier (photoreceptor) 30 or opposed with a predetermined gap therebetween, and these rollers 603 and 604 are provided on the main body side. It is configured to be engaged with a rotation drive unit (not shown) and to rotate in a predetermined direction. The developing roller 604 is formed in a cylindrical shape from a metal or alloy such as copper, stainless steel, or aluminum so that a developing bias is applied.
[0135]
In the developing device 60Y, a regulating blade 605 for regulating the thickness of the toner layer formed on the surface of the developing roller 604 to a predetermined thickness is disposed. The regulating blade 605 is composed of a plate-like member 605a such as stainless steel or phosphor bronze, and an elastic member 605b such as rubber or resin member attached to the tip of the plate-like member 605a. The rear end portion of the plate-like member 605a is fixed to the housing 601, and the elastic member 605b attached to the front end portion of the plate-like member 605a is the rear end portion of the plate-like member 605a in the rotation direction D3 of the developing roller 604. It arrange | positions so that it may be located in the upstream rather than.
[0136]
The intermediate transfer device 70 is disposed so as to face the image carrier 30 on the back surface of the intermediate transfer belt 110, the driving roller 90 and the driven roller 100, the intermediate transfer belt 110 driven by both rollers in the direction of the arrow shown in the figure. A primary transfer roller 120, a transfer belt cleaner 130 that removes residual toner on the intermediate transfer belt 110, and a drive roller 90 are arranged to face the four-color full-color image formed on the intermediate transfer belt 110 as a recording medium ( And a secondary transfer roller 140 for transferring onto the paper or the like.
[0137]
A paper feed cassette 150 is disposed at the bottom of the apparatus main body 20, and a recording medium in the paper feed cassette 150 passes through a pickup roller 160, a recording medium conveyance path 170, a secondary transfer roller 140, and a fixing device 190, and a paper discharge tray. It is comprised so that it may be conveyed by 200. Reference numeral 230 denotes a duplex printing conveyance path.
The operation of the image forming apparatus 1000 having the above configuration will be described. When an image forming signal is input from a computer (not shown), the image carrier 30, the developing roller 604 of the developing device 60 and the intermediate transfer belt 110 are rotationally driven. First, the outer peripheral surface of the image carrier 30 is charged by the charging device 40. The exposure device 50 selectively exposes the outer peripheral surface of the uniformly charged image carrier 30 according to the image information of the first color (for example, yellow) so that the yellow electrostatic latent image is obtained. An image is formed.
[0138]
On the other hand, in the developing device 60Y, the two rollers 603 and 604 rotate while being in contact with each other, whereby yellow toner is rubbed against the surface of the developing roller 604, and a toner layer having a predetermined thickness is formed on the surface of the developing roller 604. . Then, the elastic member 605b of the regulating blade 605 elastically contacts the surface of the developing roller 604, and the toner layer on the surface of the developing roller 604 is regulated to a predetermined thickness.
[0139]
At the latent image position formed on the image carrier 30, the yellow developing device 60 </ b> Y rotates and the developing roller 604 comes into contact therewith, whereby the yellow electrostatic latent image toner image is transferred onto the image carrier 30. Next, the toner image formed on the image carrier 30 is transferred onto the intermediate transfer belt 110 by the primary transfer roller 120. At this time, the secondary transfer roller 140 is separated from the intermediate transfer belt 110.
[0140]
The above processing is repeated for the second, third, and fourth colors of the image formation signal, and the latent image formation, development, and transfer are repeated by one rotation of the image carrier 30 and the intermediate transfer belt 110. Four color toner images corresponding to the contents of the image are superimposed and transferred on the intermediate transfer belt 110. Then, at the timing when the full-color image reaches the secondary transfer roller 140, the recording medium is supplied from the conveyance path 170 to the secondary transfer roller 140. At this time, the secondary transfer roller 140 is pressed against the intermediate transfer belt 110. A secondary transfer voltage is applied, and the full-color toner image on the intermediate transfer belt 110 is transferred onto the recording medium. The toner image transferred onto the recording medium is fixed by being heated and pressed by the fixing device 190. The toner remaining on the intermediate transfer belt 110 is removed by the transfer belt cleaner 130.
[0141]
In the case of double-sided printing, the recording medium exiting the fixing device 190 is switched back so that its trailing edge is the leading edge, supplied to the secondary transfer roller 140 via the double-sided printing conveyance path 230, and intermediate The full color toner image on the transfer belt 110 is transferred onto the recording medium, and is again heated and pressed by the fixing device 190 to be fixed.
In FIG. 5, a fixing device 190 according to the present invention includes a fixing roller 210 having a heat source and a pressure roller 220 pressed against the fixing roller 210, and a line connecting the axis of the fixing roller 210 and the pressure roller 220 is a horizontal line. It arrange | positions so that it may have the angle of (theta). Note that 0 ° ≦ θ ≦ 30 °.
[0142]
Next, the fixing device 190 will be described in detail.
7 and 11, the fixing roller 210 is rotatably mounted in the housing 240, and a driving gear 280 is connected to one end of the fixing roller 210. A pressure roller 220 is rotatably mounted facing the fixing roller 210. The axial length of the pressure roller 220 is shorter than that of the fixing roller 210, and a bearing 250 is provided in the vacant space, and both ends of the pressure roller 220 are supported by the bearing 250. A pressure lever 260 is rotatably provided on the bearing 250, and a pressure spring 270 is disposed between one end of the pressure lever 260 and the housing 240, whereby the pressure roller 220 and the fixing roller 210 are pressurized. It is configured to be.
[0143]
In FIG. 8, a fixing roller 210 includes a metal cylinder 210b having a heat source 210a such as a halogen lamp inside, an elastic layer 210c made of silicon rubber or the like provided on the outer periphery of the cylinder 210b, and the surface of the elastic layer 210c. A surface layer (not shown) made of fluororubber and fluororesin (for example, pertetrafluoroethylene (PTFE)) covered with a rotating shaft 210d fixed to the cylinder 210b.
[0144]
The pressure roller 220 is formed on the outer periphery of the cylindrical body 220b in the same manner as the metal cylindrical body 220b, the rotating shaft 220d fixed to the cylindrical body 220b, the bearing 250 supporting the rotating shaft 220d, and the fixing roller 210. The elastic layer 220c is provided, and a surface layer (not shown) made of fluororubber or fluororesin coated on the surface of the elastic layer 220c. The thickness of the elastic layer 210c of the fixing roller 210 is extremely smaller than the thickness of the elastic layer 220c of the pressure roller 220, thereby forming a fixing nip portion (nip portion) 340 in which the pressure roller 220 side is recessed concavely. ing.
[0145]
As shown in FIGS. 7 and 8, support shafts 290 and 300 are provided on both side surfaces of the housing 240. The support shafts 290 and 300 are respectively provided with the peeling member 310 and the pressure roller 220 on the fixing roller 210 side. The side peeling member 320 is rotatably mounted. Accordingly, the peeling members 310 and 320 are disposed on the downstream side of the fixing nip portion 340 in the recording medium conveyance direction in the axial direction of the fixing roller 210 and the pressure roller 220.
[0146]
As shown in FIGS. 9 and 10, the peeling member 310 on the fixing roller 210 side uses a resin sheet or a metal sheet as a base material, and forms a fluororesin layer on the surface of the base material. The peeling member 310 includes a plate-like peeling portion (base material) 310a, a bent portion 310b bent in an L shape toward the fixing roller 210 at the rear of the peeling portion 310a, and lower portions at both ends of the peeling portion 310a. The support piece 310c is bent in the direction, the fitting hole 310d is formed in the support piece 310c, and the guide part 310e is extended to the front of both side ends of the peeling part 310a.
[0147]
The peeling portion 310 a is disposed so as to be inclined toward the outlet (nip outlet 341) of the fixing nip portion 340, and the leading end of the peeling portion 310 a is not in contact with and close to the fixing roller 210. The support shaft 290 described in FIG. 8 is fitted in the fitting hole 310d of the support piece 310c. The guide portion 310e is urged against the housing 240 by the spring 330, whereby the front end of the guide portion 310e is in contact with the fixing roller 210, and as a result, between the front end of the peeling portion 310a and the surface of the fixing roller 210. The gap is always constant.
[0148]
The peeling member 320 on the pressure roller 220 side has the same shape as the peeling member on the fixing roller 210 side. However, as shown in FIGS. 7 and 8, the tip of the peeling portion 320a is recorded more than the tip of the peeling portion 310a. It is arranged on the downstream side in the medium conveyance direction. The tip of the guide part 320e is in contact with the peripheral surface of the bearing 250 of the pressure roller 220 at the point P, so that the gap between the tip of the peeling part 320a and the surface of the pressure roller 220 is always constant. To be.
[0149]
In the present embodiment, as shown in FIGS. 7 and 8, peeling members 310 and 320 are disposed on the downstream side of the nip portion 340 in the recording medium conveyance direction in the axial direction of the fixing roller 210 and the pressure roller 220. The front end of the peeling member 310 on the fixing roller 210 side is disposed so as to be inclined toward the outlet of the nip portion 340, and is in close contact with the fixing roller 210 without contact. The leading end of the peeling member 320 on the pressure roller 220 side is disposed downstream of the leading end of the peeling member 310 on the fixing roller 210 side in the recording medium conveyance direction.
[0150]
As shown in FIG. 10, the guide member 310 e of the peeling member 310 on the fixing roller 210 side is urged to the housing 240 by the spring 330, so that the tip of the guide portion 310 e is in contact with the fixing roller 210. As a result, the positioning is performed so that the gap between the tip of the peeling portion 310a and the surface of the fixing roller 210 is always constant.
[0151]
The peeling member 320 on the pressure roller 220 side has the same shape as the peeling member on the fixing roller 210 side, and as shown in FIGS. 7 and 8, the tip of the peeling portion 320a is a recording medium more than the tip of the peeling portion 310a. The tip of the guide part 320e is disposed at the downstream side in the conveying direction, and is in contact with the surface of the bearing 250 of the pressure roller 220 at the point P, whereby the tip of the peeling part 320a and the surface of the pressure roller 220 are Positioning is performed so that the gap between them is always constant. Therefore, as shown in FIG. 11, the axial length of the pressure roller 220 is shorter than that of the fixing roller 210, and a bearing 250 is provided in the vacant space. It is supported.
[0152]
In the case of double-sided printing, the recording medium printed on one side is peeled off by the peeling member 310 on the fixing roller 210 side, and then switched back so that the trailing edge of the recording medium becomes the leading edge, and then passes through the double-sided printing conveyance path 230. The full-color toner image on the intermediate transfer belt 110 is supplied to the secondary transfer roller 140 and is transferred onto the recording medium, and is heated and pressed again by the fixing roller 210. At this time, it adheres to the pressure roller 220 and wraps around. The recording medium is peeled off by the peeling member 320 on the pressure roller 220 side.
[0153]
As described above, in the fixing device according to the present embodiment, the peeling is provided in the vicinity of the fixing roller and the pressure roller in the axial direction of the fixing roller and the pressure roller and on the downstream side of the fixing nip portion in the recording medium conveyance direction. The positioning of the peeling member on the fixing roller side is performed on the surface of the fixing roller, and the positioning of the peeling member on the pressure roller side is performed on the bearing surface of the pressure roller, so that recording from the fixing roller and the pressure roller is performed. The peelability of the medium can be improved.
[0154]
In this embodiment, as shown in FIG. 12, the fixing roller 210 and the pressure roller 220 are arranged in a substantially horizontal state, and the recording medium 500 is discharged from the fixing nip portion 340 upward. Is an arrangement angle θ of the peeling member 310 with respect to the tangent S of the nip outlet 341 of the fixing nip portion 340._AIs preferably set in the range of −5 to 25 °. Arrangement angle θ of peeling member 310 with respect to tangent S of nip outlet 341 of fixing nip 340_ABy setting to a value in such a range, streaks are less likely to occur in the image, and the peelability is improved. Arrangement angle θ_AThe fixing roller 210 side is “+” and the pressure roller side is “−”.
[0155]
In addition, the fixing roller 210 and the pressure roller 220 have, for example, outer diameters that are substantially constant in the respective axial directions (which may have a substantially cylindrical shape, but the outer diameters are small near both ends. It may have a so-called crown shape that is large in the vicinity of the central portion, or a so-called reverse crown shape in which the outer diameter is large in the vicinity of both end portions and small in the vicinity of the central portion.
[0156]
For example, when the fixing roller 210 and the pressure roller 220 have an inverted crown shape as shown in FIG. 13, the cross-sectional shape of the peeling member 310 is preferably as shown in FIG. Further, when the fixing roller 210 and the pressure roller 220 have a crown shape as shown in FIG. 15, the cross-sectional shape of the peeling member 310 is preferably as shown in FIG.
[0157]
In this way, when the peeling member 310 disposed along the fixing roller 210 has a shape that follows the shape of the nip outlet 341 of the nip portion 340, the peeling member 310 side of the peeling member 310 at the time of peeling. Effectively eliminates adverse effects caused by the increased contact between the side edge of the recording medium and the recording medium, and the contact pressure between the two is concentrated in part, for example, wrapping of the recording medium, disturbance in the formed image, generation of streaks, etc. Can be prevented and suppressed.
[0158]
As shown in FIG. 17, in the fixing device 190, the gap G <b> 2 [μm] between the fixing roller 210 and the peeling member 310 near the axial end of the fixing roller 210 is the center in the axial direction of the fixing roller 210. It is preferable that the gap is larger than the gap G1 [μm] between the fixing roller 210 and the peeling member 310 in the vicinity of the portion. By satisfying such a relationship, the following effects can be obtained.
[0159]
That is, since the gap between the peeling member 310 and the fixing roller 210 is small in the vicinity of the central portion in the length direction, the gap management can be easily performed without greatly deteriorating the peeling property, and the fixing device 190 can be manufactured. It becomes easy. Further, even when a foreign substance enters or a paper jam occurs, it is difficult to cause damage to the peeling member 310 and the fixing roller 210 due to these, and the durability and reliability of the peeling member 310 and the fixing roller are improved, and fixing is performed. The durability and reliability of the apparatus 190 and the image forming apparatus 1000 are also improved. Note that the relationship between G1 and G2 as described above can be obtained by, for example, forming the peeling member 310 into a bow shape, forming the tip 310f of the peeling member 310 into a bow shape, or forming the fixing roller 210 into a crown shape. Can be satisfied.
[0160]
In the fixing device as described above, the length of the fixing nip 340 is such that the time required for the toner particles to pass through the fixing nip 340 is 0.02 to 0.2 seconds. Is preferable, and it is more preferable that it is 0.03-0.1 second. When the time required for the toner particles to pass through the fixing nip portion 340 is within such a range, the toner is heated up to the melting temperature, and the toner is not melted sufficiently, and the releasability to the fixing roller is sufficient. Secured.
[0161]
The fixing device 190 is suitable for high-speed printing (high-speed fixing, high-speed image formation). Specifically, the feeding speed (feeding speed) of the recording medium 500 is 0.05 to 1.0 m / second. It is preferable that it is 0.2 to 0.5 m / sec. As described above, according to the present invention, even when the toner is fixed to the recording medium 500 at a relatively high speed, it is possible to prevent the image from causing streaking or disturbance, and the recording medium 500 may be entangled. It is difficult to cause poor peeling.
[0162]
Further, the temperature of the fixing nip portion 340 during operation is preferably 100 to 220 ° C, and more preferably 120 to 200 ° C. When the temperature of the fixing nip portion 340 is within such a range, it is possible to sufficiently prevent a decrease in toner fixing strength due to a temperature drop (temperature drop) when the paper passes.
Further, the fixing setting temperature (setting temperature on the surface of the fixing roller 210) during operation is preferably 110 to 220 ° C, and more preferably 130 to 200 ° C. If the set temperature of the fixing roller 210 is within this range, it is possible to achieve both fixing strength of the toner and shortening of the temperature rise time (warm up time).
[0163]
As described above, the fixing device 190 described above is suitable for high-speed printing (high-speed fixing, high-speed image formation). However, in such a fixing device, since the toner is in a high temperature state even when the recording medium on which the toner is fixed comes into contact with the peeling member, when the conventional toner is used, the toner comes into contact with the peeling member. There is a possibility that the fixed image may be disturbed. Further, if the fixed toner is in a molten state (low viscosity state) and contacts the peeling member, it may be difficult to reliably peel off the recording medium.
[0164]
On the other hand, the toner of the present invention can be suitably applied to the fixing device 190 described above. That is, since the toner of the present invention contains amorphous polyester having a relatively low softening point, the toner of the present invention is surely fixed to the recording medium when passing through the fixing nip portion 340. Includes a block polyester having a crystalline block, and the colorant is unevenly distributed in the second region mainly composed of amorphous polyester. For this reason, a crystal having a high hardness and an appropriate size is likely to be precipitated in the toner (inside the first region). The presence of such crystals makes it possible to prevent the melt viscosity of the toner from being lower than a predetermined value even when the temperature is relatively high, such as during fixing, and partially during fixing. There will be a hard site. As a result, even when the fixed image of the toner comes into contact with the peeling member, the formed image is unlikely to be disturbed or distorted. Further, in the recording medium on which the toner of the present invention is fixed, peeling failure is not particularly likely to occur, and the peeling member reliably peels from the fixing roller.
[0165]
[Toner Production Method]
Next, a preferred embodiment of the toner production method of the present invention will be described. FIG. 1 is a longitudinal sectional view schematically showing the configuration of a kneader and a cooler used in the first embodiment of the toner production method of the present invention. In the following description, the left side is “base end” and the right side is “tip” in FIG. 1 (the same applies to FIG. 18 described later).
[0166]
<1A> First kneading step (first kneading process)
First, a first raw material 7 containing at least amorphous polyester and a colorant among the above materials is kneaded to obtain a first kneaded product 8 (first kneading step). The first raw material 7 to be used in the first kneading step is preferably one that has been uniformly mixed in advance by a mixer such as a Henschel mixer.
[0167]
The first kneading step (first kneading process) can be performed using a kneader 1 as shown in FIG.
The kneading machine 1 includes a process unit 12 that kneads the first raw material 7 while transporting it, a head unit 13 that extrudes a first kneaded product 8 obtained by kneading into a predetermined cross-sectional shape, and a process unit 12. And a feeder 14 for supplying the first raw material 7 therein.
[0168]
The process unit 12 includes a barrel 121, screws 122 and 123 inserted into the barrel 121, and a fixing member 124 for fixing the head unit 13 to the tip of the barrel 121.
In the process unit 12, when the screws 122 and 123 rotate, a shearing force is applied to the first raw material 7 supplied from the feeder 14, and each component constituting the first raw material 7 is sufficiently uniformly dispersed. A first kneaded product 8 is obtained.
[0169]
Raw material temperature T in the first kneading step_K1Is different depending on the composition of the first raw material 7, the softening point, and the like, but is preferably 80 to 160 ° C, more preferably 100 to 150 ° C. When the raw material temperature is less than the lower limit, the viscosity of the first raw material 7 becomes too high, and it becomes difficult to knead so that each constituent component is sufficiently uniformly dispersed. On the other hand, when the raw material temperature exceeds the upper limit, the material is likely to be thermally decomposed, oxidized and deteriorated, and aggregation, macrophase separation, etc. are likely to occur, and the function of the finally obtained toner may be lowered. .
In the present embodiment, the first raw material 7 only needs to contain at least amorphous polyester and a colorant, and may contain components other than these. For example, the 1st raw material 7 may contain the block polyester contained in the 2nd raw material 9 mentioned later as a part of the structural component.
[0170]
<1B> Extrusion process
The first kneaded product 8 obtained in the first kneading step is pushed out of the kneader 1 through the head unit 13 by the rotation of the screws 122 and 123.
The head unit 13 has an internal space 131 into which the first kneaded product 8 is fed from the process unit 12 and an extrusion port 132 through which the first kneaded product 8 is extruded.
[0171]
In the illustrated configuration, the internal space 131 has a cross-sectional area gradually decreasing portion 133 in which the cross-sectional area gradually decreases in the direction of the extrusion port 132.
By having such a cross-sectional area gradually decreasing portion 133, the extrusion amount of the first kneaded material 8 extruded from the extrusion port 132 is stabilized, and the cooling rate of the first kneaded material 8 in the cooling step described later is stable. To do. As a result, the toner produced using the toner has a small variation in characteristics among the toner particles, and has excellent overall characteristics.
[0172]
<1C> Cooling process
The softened first kneaded product 8 extruded from the extrusion port 132 of the head unit 13 is cooled by the cooler 6 and solidified.
The cooler 6 includes rolls 61, 62, 63, 64 and belts 65, 66.
The belt 65 is wound around a roll 61 and a roll 62. Similarly, the belt 66 is wound around a roll 63 and a roll 64.
[0173]
The rolls 61, 62, 63, 64 rotate about the rotation shafts 611, 621, 631, 641 in the directions indicated by e, f, g, h in the figure. Thereby, the first kneaded material 8 pushed out from the extrusion port 132 of the kneading machine 1 is introduced between the belt 65 and the belt 66. The first kneaded material 8 introduced between the belt 65 and the belt 66 is cooled while being formed into a plate shape having a substantially uniform thickness. The cooled first kneaded material 8 is discharged from the discharge portion 67. The belts 65 and 66 are cooled by a method such as water cooling or air cooling. When such a belt type is used as the cooler, the contact time between the kneaded product extruded from the kneader and the cooling body (belt) can be increased, and the cooling efficiency of the kneaded product is particularly excellent. Can be.
[0174]
<1D> Coarse grinding process
The 1st kneaded material 8 which passed through the cooling process as mentioned above is coarsely pulverized as needed. The method of coarse pulverization is not particularly limited, and can be performed using various pulverizers and crushers such as a ball mill, a vibration mill, a hammer mill, a pin mill, and a feather mill.
[0175]
Through such a coarse pulverization step, the first kneaded material is usually coarsely pulverized to such an extent that it passes through a mesh having an opening diameter of several mm. The average particle size of the pulverized first kneaded material is preferably 3 mm or less, and more preferably 2 mm or less. When the average particle size of the first kneaded product is such a value, it can be finely dispersed sufficiently uniformly in the second kneading step described later. As a result, the finally obtained toner has a small variation in characteristics among the particles, and the reliability of the toner as a whole is improved.
The first kneading step is not necessarily the above-described step (1A to 1D), and may be a wet kneading method using a flushing pigment.
[0176]
<1E> Second kneading step (second kneading process)
Next, the first kneaded product 8 obtained as described above and the second raw material 9 containing at least a block polyester are kneaded to obtain a second kneaded product 10 (second kneading step). . The first kneaded product 8 and the second raw material 9 to be used in the second kneading step are preferably those which are uniformly mixed in advance by a mixer such as a Henschel mixer.
[0177]
In this way, by performing the kneading process in two stages, the second kneaded product 10 (the same applies to the toner production powder described later) is contained in the first region mainly composed of block polyester. And a second region mainly composed of amorphous polyester, and the concentration of the colorant in the second region is higher than the concentration of the colorant in the first region. 2) that is unevenly distributed in the region 2). Then, by using the second kneaded material 10 as described above, the concentration of the colorant contained in the toner of the present invention, that is, the second region is more than the concentration of the colorant contained in the first region. High toner can be obtained easily and reliably.
The second kneading step (second kneading process) can be performed using a kneader 1 as shown in FIG. 1, similarly to the first kneading step described above.
[0178]
The first kneaded material 8 and the second raw material 9 stored in the feeder 14 are supplied into the process unit 12. The first kneaded material 8 and the second raw material 9 supplied into the process section 12 are kneaded by rotating the screws 122 and 123, whereby the second kneaded material 10 is obtained.
Raw material temperature in the second kneading step (temperature of the first kneaded product 8 and the second raw material 9) T_K2Is different depending on the composition of the first kneaded material 8 and the second raw material 9, the softening point, etc., but is preferably 80 to 260 ° C, more preferably 100 to 150 ° C. When the raw material temperature is less than the lower limit, the viscosity of the raw materials (first kneaded material 8 and second raw material 9) becomes too high, and it becomes difficult to finely disperse sufficiently (microphase separation). . On the other hand, if the raw material temperature exceeds the upper limit, the material is likely to undergo thermal decomposition, oxidative deterioration, aggregation, macrophase separation, etc., and the function of the finally obtained toner is sufficiently high. Can be difficult to do.
[0179]
In addition, the softening point of amorphous polyester is T_1/2(A) [° C], the melting point of the block polyester is T_m(B) [° C.] The material temperature (kneading temperature) in the second kneading step is T_K2[℃], T_m(B)> T_K2> T_1/2It is preferable to satisfy the relationship (A). By satisfying such a relationship, the first region and the second region can be phase-separated (micro-separated) to an appropriate size, and the coloring contained in the first kneaded material 8 It is possible to effectively prevent the agent from moving into the first region. As a result, in the obtained second kneaded material 10, the ratio of the content of the colorant contained in the second region to the content of the colorant contained in the first region can be particularly increased. . As a result, the above-described effect becomes more remarkable in the finally obtained toner.
In addition, in this embodiment, the 2nd raw material 9 should just contain block polyester at least, and may contain components other than these. For example, the second raw material 9 may include an amorphous polyester contained in the first raw material 7 as a part of its constituent components.
[0180]
<1F> Extrusion process
The second kneaded product 10 obtained in the second kneading step is pushed out of the kneader 1 through the head unit 13 by the rotation of the screws 122 and 123.
In the illustrated configuration, the internal space 131 has a cross-sectional area gradually decreasing portion 133 in which the cross-sectional area gradually decreases in the direction of the extrusion port 132.
[0181]
By having such a cross-sectional area gradually decreasing portion 133, the extrusion amount of the second kneaded product 10 extruded from the extrusion port 132 is stabilized, and the cooling rate of the second kneaded product 10 in the cooling step described later is stable. To do. As a result, the toner produced using the toner has a small variation in characteristics among the toner particles, and has excellent overall characteristics.
[0182]
<1G> Cooling process
The softened second kneaded product 10 extruded from the extrusion port 132 of the head unit 13 is cooled by the cooler 6 and solidified.
The rolls 61, 62, 63, and 64 rotate about the rotation shafts 611, 621, 631, and 641 in the directions indicated by e, f, g, and h in the drawing, respectively, and thereby the extrusion port 132 of the kneader 1. The second kneaded material 10 extruded from is introduced between the belt 65 and the belt 66. The second kneaded material 10 introduced between the belt 65 and the belt 66 is cooled while being formed into a plate shape having a substantially uniform thickness. The cooled second kneaded material 10 is discharged from the discharge part 67.
[0183]
By the way, in the second kneading step, since a shearing force is applied to the raw material (second kneaded material), macrophase separation or the like is sufficiently prevented, but the second kneading step is finished. Since the kneaded product is not subjected to a shearing force, if it is left for a long period of time, macro phase separation or the like may occur. Therefore, it is preferable to cool the second kneaded material obtained as described above as soon as possible. Specifically, the cooling rate of the second kneaded product (for example, the cooling rate when the second kneaded product is cooled to about 60 ° C.) is preferably −3 ° C./second or more, and preferably −5 to More preferably, it is −100 ° C./second. Also, the time required from the end of the second kneading step (when the shear force is no longer applied) to the completion of the cooling step (for example, the time required to cool the temperature of the second kneaded product to 60 ° C. or lower) ) Is preferably 20 seconds or shorter, more preferably 3 to 12 seconds.
[0184]
<1H> Granulation process
By granulating the second kneaded material 10 that has undergone the cooling step as described above, a powder for toner production is obtained.
In the present embodiment, the granulation step includes a pulverization step and a thermal spheronization step as described below. Note that the thermal spheronization step is not necessarily performed.
[0185]
(1) Grinding process
First, the 2nd kneaded material 10 which passed through the cooling process as mentioned above is grind | pulverized.
The pulverization method is not particularly limited, and can be performed using various pulverizers and crushers such as a ball mill, a vibration mill, a hammer mill, a jet mill, a pin mill, and a feather mill.
[0186]
The pulverization process may be performed in multiple steps (for example, two stages of a coarse pulverization process and a fine pulverization process).
In addition, after such a pulverization step, a classification process or the like may be performed as necessary.
For the classification treatment, for example, a sieve, an airflow classifier or the like can be used.
[0187]
In addition, the obtained powder for toner production may be subjected to an external addition treatment to which an external additive is added as a pretreatment for a thermal spheronization step described later. By performing such an external treatment as a pretreatment, the fluidity and dispersibility of the toner particles are improved, and the toner can be more reliably prevented and suppressed from being fused by heat. In addition, the external additive as described above can be used for the external addition treatment as such pretreatment. Further, such an external addition treatment as a pretreatment can be suitably performed by using a Henschel mixer or the like, as will be described later, in the same manner as an external addition step as a subsequent step of the thermal spheronization treatment.
[0188]
(2) Thermal spheronization process (thermal spheronization process)
Next, a thermal spheronization treatment is performed in which the powder (powder for toner production) obtained in the pulverization step is heated to be spheroidized.
By performing such a thermal spheronization treatment, relatively large irregularities on the surface of the powder for toner production are removed, and the circularity becomes relatively high. As a result, the finally obtained toner has a small difference in charging characteristics between the individual toner powders, and the developability on the photoconductor is improved and the toner adheres to the photoconductor (filming). ) Is more effectively prevented, and the toner transfer efficiency is further improved.
[0189]
In particular, the present invention includes a block polyester having a crystalline block (because it includes a first region mainly composed of a block polyester), so that the shape stability of the powder for toner production is improved during the thermal spheronization process. The amorphous polyester can be sufficiently softened while securing a certain degree. Therefore, in the present invention, compared with the case where a raw material not containing block polyester is used, the thermal spheronization treatment can be efficiently performed, and the degree of circularity of the finally obtained toner (toner particles) can be relatively easily achieved. Can be relatively high. Moreover, as a result, the effect by the thermal spheroidization process mentioned above can be exhibited more effectively.
[0190]
The thermal spheronization treatment can be performed by injecting the powder for toner production obtained in the pulverization step into a heated atmosphere using, for example, compressed air. At this time, the atmospheric temperature is preferably 210 to 320 ° C, and more preferably 230 to 300 ° C. If the atmospheric temperature is less than the lower limit, it may be difficult to sufficiently increase the circularity. On the other hand, when the ambient temperature exceeds the upper limit, the material is likely to be thermally decomposed, oxidized and deteriorated, and aggregation, phase separation and the like are likely to occur, and the function of the finally obtained toner may be lowered.
[0191]
The melting point of the block polyester is T_m(B) [° C], the softening point of the amorphous polyester is T_1/2(A) At [° C.], the ambient temperature T during the thermal spheronization process_S[° C] is (T_1/2(A) +120) ≦ T_S≤ (T_mIt is preferable to satisfy the relationship (B) +90), and (T_1/2(A) +140) ≦ T_S≤ (T_mIt is more preferable to satisfy the relationship (B) +70). Such atmospheric temperature T_sBy carrying out the thermal spheronization treatment with the toner, the degree of circularity of the toner particles obtained is made relatively high while sufficiently preventing the occurrence of thermal decomposition, oxidative degradation, aggregation, phase separation, etc. be able to.
[0192]
By performing such treatment, the average circularity R of the finally obtained toner (toner powder) can be easily and reliably controlled to a value in the above-described range.
Further, after such a thermal spheronization step, a treatment such as a classification treatment may be performed as necessary.
Moreover, you may perform such a thermal spheronization process in a liquid.
Note that the thermal spheronization process is not necessarily performed.
For the classification treatment, for example, a sieve, an airflow classifier or the like can be used.
[0193]
<1I> External addition process (external addition process)
Next, the external additive as described above is applied to the pulverized and classified powder for toner production that has been heat spheroidized or not heat spheroidized.
Such application of the external additive can be suitably performed by, for example, mixing the toner manufacturing powder and the external additive using a Henschel mixer or the like.
[0194]
Further, the toner powder obtained in this manner has a coating ratio of the external additive (the ratio of the area covered by the external additive to the surface area of the toner particles, and the sphere corresponding to the average particle diameter of the external additive is the average particle diameter of the toner. The calculated coverage when a sphere having a diameter corresponding to 6-way fine packing is preferably 100 to 300%, and more preferably 120 to 220%. If the coverage of the external additive is less than the lower limit, the effect of the external additive as described above may not be sufficiently exhibited. On the other hand, when the coverage of the external additive exceeds the upper limit, the toner fixability tends to decrease.
[0195]
Further, in the toner, substantially all of the external additive may be attached to the toner particles (mother particles), or a part of the external additive may be released from the surface of the toner particles. Good. That is, the toner may contain an external additive released from the toner particles.
Thus, when the toner contains an external additive released from the mother particles (hereinafter also referred to as “free external additive”), such a free external additive is, for example, opposite to the toner particles. It can function as a microcarrier that is charged to polarity. When such a free external additive functioning as a microcarrier is included in the toner, toner particles having a reverse chargeability during development or the like (toner particles that are charged with a polarity opposite to the polarity that the toner particles should originally exhibit when charged) ) Can be effectively prevented and suppressed. As a result, the toner is less likely to cause inconveniences such as so-called fog.
[0196]
The amount of the external additive released from the toner particles is, for example, the annual meeting of the Electrophotographic Society (95 times) “Japan Hardcopy '97”, “New External Evaluation Method-Toner Analysis with Particle Analyzer” (Suzuki) Measurement is possible by applying the method disclosed in Toshiyuki, Toshio Takahara, sponsored by the Electrophotographic Society, July 9-11, 1997). Hereinafter, an example of a method for measuring the amount of free external additive by a particle analyzer (PT1000) in the case of using (rutile-anatase type) titanium oxide as an external additive will be described.
[0197]
In this measuring method, titanium oxide (TiO 2) is formed on the surface of the mother particle made of resin (C).₂The toner T particles formed by adhering the external additive comprising the above are introduced into the plasma to excite the toner particles, obtain an emission spectrum associated with the excitation, and perform the elemental analysis for measurement. It is.
First, an external additive (TiO 2) is added to the toner manufacturing powder (mother powder).₂When the toner particles to which the particles are attached are introduced into the plasma, the mother particles (C) and the external additive (TiO₂) Both emit light. At this time, the base particles (C) and the external additive (TiO₂) Are simultaneously introduced into the plasma, the mother particles (C) and the external additive (TiO₂) Will emit light at the same time. Thus, the base particles (C) and the external additive (TiO₂) Simultaneously emits light, the base particles (C) and the external additive (TiO₂) And are synchronized. In other words, the base particles (C) and the external additive (TiO₂) Is synchronized with the external additive (TiO₂) Represents the state of adhering to the mother particles (C).
[0198]
External additives (TiO₂) Is not adhered to the mother particles (C) and the external additive (TiO) released from the mother particles (C).₂) Is introduced into the plasma, the base particles (C) and the external additive (TiO₂) Emit light, but at this time, the mother particles (C) and the external additive (TiO 2)₂) Are introduced into the plasma at different times, so that the mother particles (C) and the external additive (TiO 2)₂(For example, when the mother particles are introduced into the plasma prior to the external additive, the mother particles emit light first, and then the external additive emits light later).
[0199]
Thus, the base particles (C) and the external additive (TiO₂) Emit light at different times, the mother particles (C) and the external additive (TiO₂) Is not synchronized (that is, asynchronous). In other words, the base particles (C) and the external additive (TiO₂) Is asynchronous with the external additive (TiO₂) Represents a state of not adhering to the mother particle (C).
[0200]
Further, in the emission spectrum obtained as described above, the height of the emission signal indicates the intensity of the emission, but this emission intensity is not included in the size or shape of the particles but is included in the particles. Its elements (C, TiO₂) Is proportional to the number of atoms. Therefore, in order to express the emission intensity of the element as the size of the particle, the mother particle (C) and the external additive (TiO₂) Emission of these base particles (C) and external additives (TiO₂) Are assumed to be true spherical particles, and the true spherical particles at this time are referred to as equivalent particles, and these particle sizes are referred to as equivalent particle sizes. Since the external additive is very small, it is impossible to detect each of these particles one by one. Therefore, the detected emission signals of the external additive are added together and converted into one equivalent particle for analysis.
[0201]
When the equivalent particle diameters of the equivalent particles obtained from the emission spectra of the mother particles and the external additive are plotted for each toner particle, an equivalent particle diameter distribution diagram of the toner particles as shown in FIG. 4 is obtained. It is done.
In FIG. 4, the horizontal axis represents the equivalent particle diameter of the base particle (C), and the vertical axis represents the external additive (TiO 2).₂). The equivalent particles on the horizontal axis are external additives (TiO₂) Represents an asynchronous mother particle (C) not attached, and the equivalent particle on the vertical axis represents an asynchronous external additive (TiO 2) released from the mother particle (C).₂). Equivalent particles that are not on the horizontal and vertical axes are added to the base particles (C) as an external additive (TiO 2).₂) Represents the synchronous toner attached. Thus, the external additive (TiO 2) for the toner base particles (C) is obtained.₂) Is analyzed.
[0202]
The amount of rutile-anatase-type titanium oxide released from the toner particles that can be measured in this way (ratio of rutile-anatase-type titanium oxide contained in the toner as a free external additive) is 0.1 to 5.0 wt% is preferable, and 0.5 to 3.0 wt% is more preferable. If the ratio of the free external additive is too small, the above-mentioned function as a microcarrier may not be sufficiently exhibited. On the other hand, when the ratio of the free external additive exceeds the upper limit, the free external additive adheres to the toner contact member and filming is likely to occur.
[0203]
Next, a second embodiment of the toner manufacturing method of the present invention will be described.
FIG. 18 is a longitudinal sectional view schematically showing the configuration of a kneader and a cooler used in the second embodiment of the toner production method of the present invention. Hereinafter, the toner manufacturing method according to the second embodiment will be described with a focus on differences from the first embodiment described above, and descriptions of similar matters will be omitted.
The kneading machine 1 ′ used in the present embodiment includes a first kneading unit 2 that performs a first kneading process (first kneading process) and a second kneading process (second kneading process). A kneading part 3; a connecting part 4 for connecting the first kneading part 2 and the second kneading part 3; and a head part 5 for extruding the second kneaded product 10 in a predetermined cross-sectional shape. ing.
[0204]
<2A> First kneading step (first kneading process)
First, the first raw material 7 containing at least amorphous polyester and a colorant among the above materials is kneaded to obtain a first kneaded product (first kneading step). The first raw material 7 to be used in the first kneading step is preferably one that has been uniformly mixed in advance by a mixer such as a Henschel mixer.
[0205]
The first kneading step (first kneading process) is performed in the first kneading unit 2.
The first kneading unit 2 includes a feeder 21 that stores the first raw material 7 and a process unit 22 that kneads the first raw material 7 supplied from the feeder 21 while being conveyed. The process unit 22 includes a barrel 221 and screws 222 and 223 inserted into the barrel 221.
[0206]
In the process part 22, when the screws 222 and 223 rotate, a shearing force is applied to the first raw material 7 supplied from the feeder 21, and each component constituting the first raw material 7 is sufficiently uniformly dispersed. A first kneaded product 8 is obtained.
The first kneaded material 8 obtained as described above is fed into the second kneading unit 3 through the connection unit 4 by the rotation of the screws 222 and 223.
[0207]
<2B> Second kneading step (second kneading process)
Next, the first kneaded product 8 obtained in the first kneading step and the second raw material 9 containing at least a block polyester are kneaded (second kneading step).
The second kneading step (second kneading process) is performed in the second kneading unit 3.
The second kneading unit 3 includes a feeder 31 that stores the second raw material 9 and a process unit 32 that kneads while conveying the second raw material 9 supplied from the feeder 31. The process unit 32 includes a barrel 321, screws 322 and 323 inserted into the barrel 321, and a fixing member 324 for fixing the head unit 5 to the tip of the barrel 321.
In the process unit 32, the second raw material supplied from the feeder 31 and the first kneaded material 8 fed from the first kneading unit 2 through the connection unit 4 by the rotation of the screws 322 and 323 and the feeder 31. 9 is kneaded to obtain a second kneaded material 10.
[0208]
<2C> Extrusion process
The second kneaded material 10 kneaded in the process unit 32 is pushed out of the kneader 1 through the head unit 5 by the rotation of the screws 322 and 323.
The head unit 5 has an internal space 51 into which the second kneaded product 10 is fed from the process unit 32 and an extrusion port 52 through which the second kneaded product 10 is extruded.
[0209]
In the illustrated configuration, the internal space 51 has a cross-sectional area gradually decreasing portion 53 in which the cross-sectional area gradually decreases in the direction of the extrusion port 52.
By having such a cross-sectional area gradually decreasing portion 53, the extrusion amount of the second kneaded product 10 extruded from the extrusion port 52 is stabilized, and the cooling rate of the second kneaded product 10 in the cooling step described later is stable. To do. As a result, the toner produced using the toner has a small variation in characteristics among the toner particles, and has excellent overall characteristics.
[0210]
<2D> Cooling process
The softened second kneaded product 10 extruded from the extrusion port 52 of the head unit 5 is cooled by the cooler 6 and solidified in the same manner as in the first embodiment.
<2E> Granulation process
Same as step <1H> described above.
<2F> External addition process (external addition process)
Same as step <1I> described above.
[0211]
As described above, in the present embodiment, a kneader (a two-stage barrel type kneader) having a first kneading unit and a second kneading unit is used. Accordingly, the first kneading step and the second kneading step can be performed continuously, and the steps such as <1B> to <1D> described in the first embodiment can be omitted. it can.
As a result, toner productivity is improved.
[0212]
Further, by using a kneader as shown in FIG. 18, the temperature fluctuation of the raw material (particularly, the first raw material) used for the toner production can be made relatively small, and the heat applied to the raw material used for the toner production. Reduce history. Moreover, the time during which the kneaded product in a heated state comes into contact with air can be shortened. As a result, it is possible to more effectively prevent the deterioration of the constituent components of the toner, and the reliability of the finally obtained toner is further improved.
[0213]
As described above, the toner and the toner production method of the present invention have been described based on the preferred embodiments, but the present invention is not limited to this.
For example, the toner of the present invention is not limited to those manufactured by the method described above. For example, in the above-described embodiment, the method of performing the kneading of the constituent material of the toner in two steps of the first kneading step and the second kneading step has been described, but the kneading step is performed three times or more. It may be performed separately or only once.
[0214]
Further, different kneading apparatuses may be used in the first kneading step and the second kneading step, and kneading conditions such as the number of rotations of the screw may be different.
In the embodiment described above, the configuration using a continuous twin-screw extruder as the kneader has been described. However, the kneader used for kneading the raw materials (first kneading and second kneading) is limited to this. Not. For kneading the raw materials, for example, various kneaders such as a kneader, a batch type triaxial roll, a continuous biaxial roll, a wheel mixer, and a blade type mixer can be used.
[0215]
In the present invention, not only the dry kneading method as described above but also a wet method (for example, a flushing method) may be applied.
In the above-described embodiment, the toner manufacturing powder obtained through the granulation process has been described as being obtained by performing an external addition process. However, the toner powder can be obtained by the granulation process without performing the external addition process. The powder (toner production powder) may be used as the toner as it is. In the above-described embodiment, the thermal spheronization process is described as being performed after the pulverization step. However, such a thermal spheronization process may be omitted.
[0216]
In the above-described embodiment, the powder for toner production (toner particles) is described as using a powder obtained by a pulverization method. However, the powder produced by other methods such as a spray drying method or a polymerization method is used. It may be.
In the above-described embodiment, the configuration in which the thermal spheronization process is performed under dry conditions has been described. However, the thermal spheronization process may be performed under wet conditions such as in a solution.
[0217]
In the illustrated configuration, a kneader having two screws has been described. However, the number of screws may be one or three or more.
In the above-described embodiment, the configuration using the belt type as the cooler has been described. However, for example, a roll type (cooling roll type) cooler may be used. Moreover, the cooling of the kneaded material extruded from the extrusion port of the kneader is not limited to the one using the above-described cooling machine, and may be performed by air cooling or the like, for example.
[0218]
In the embodiment described above, the rutile-anatase type titanium oxide has been described as being added as an external additive. For example, by using the rutile-anatase-type titanium oxide as one component of the raw material provided for the kneading step. The toner may be contained in the toner.
In the above-described embodiment, ΔT obtained by measuring the endothermic peak of the melting point by differential scanning calorimetry (DSC) has been described as an index indicating crystallinity. However, the index indicating crystallinity is not limited to this. For example, as an index representing crystallinity, a crystallinity measured by a density method, an X-ray method, an infrared method, a nuclear magnetic resonance absorption method, or the like may be used.
[0219]
In addition, the fixing device and the image forming apparatus to which the toner of the present invention is applied are not limited to those described in the above-described embodiments, and each unit constituting the fixing device and the image forming apparatus can exhibit the same function. Any configuration can be substituted.
For example, in the above-described embodiment, the contact type fixing device has been described. However, the present invention is not limited to such a contact type fixing device, and may be applied to a non-contact type fixing device. Good.
[0220]
【Example】
[1] Production of polyester
Prior to toner production, the following three types of polyesters A, A ', B, C, and D were produced.
[1.1] Production of polyester A (amorphous polyester)
First, a mixture of neopentyl glycol: 36 mol parts, ethylene glycol: 36 mol parts, 1,4-cyclohexanediol: 48 mol parts, dimethyl terephthalate: 90 mol parts, and phthalic anhydride: 10 mol parts was prepared.
[0221]
In a 2 liter four-necked flask, a reflux condenser, a distillation tower, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer were installed according to a conventional method. A mixture of the diol component and the dicarboxylic acid component: 1000 g , 1 g of an esterification condensation catalyst (titanium tetrabutoxide (PPB)) was placed in the 2-liter four-necked flask. Thereafter, the esterification reaction was allowed to proceed at a material temperature of 180 ° C. while the generated water and methanol were allowed to flow out of the distillation tower. When water and methanol no longer flowed out of the distillation column, the distillation column was removed from the 2-liter four-necked flask and connected to a vacuum pump. With the pressure in the system reduced to 5 mmHg or less, the temperature was set to 200 ° C., and the stirring rotation speed: stirring at 150 rpm, the free diol generated in the condensation reaction was discharged out of the system, and the resulting reaction product Was polyester A (PES-A).
[0222]
With respect to the obtained polyester A, an attempt was made to measure the endothermic peak of the melting point with a differential scanning calorimeter. As a result, a sharp peak that could be determined to be an absorption peak at the melting point could not be confirmed. Also, the softening point T of polyester A_1/2Is 111 ° C, glass transition point T_gIs 60 ° C. and the weight average molecular weight Mw is 1.3 × 10⁴Met.
[0223]
[1.2] Production of polyester A '(amorphous polyester)
First, a mixture of neopentyl glycol: 96 mol parts, ethylene glycol: 12 mol parts, 1,4-cyclohexanediol: 12 mol parts, and dimethyl terephthalate: 100 mol parts was prepared.
In a 2 liter four-necked flask, a reflux condenser, a distillation tower, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer were installed according to a conventional method. A mixture of the diol component and the dicarboxylic acid component: 1000 g , 1 g of an esterification condensation catalyst (titanium tetrabutoxide (PPB)) was placed in the 2-liter four-necked flask. Thereafter, the esterification reaction was allowed to proceed at a material temperature of 180 ° C. while the generated water and methanol were allowed to flow out of the distillation tower. When water and methanol no longer flowed out of the distillation column, the distillation column was removed from the 2-liter four-necked flask and connected to a vacuum pump. With the pressure in the system reduced to 5 mmHg or less, the temperature was set to 200 ° C., and the stirring rotation speed: stirring at 150 rpm, the free diol generated in the condensation reaction was discharged out of the system, and the resulting reaction product Was polyester A ′ (PES-A ′).
[0224]
An attempt was made to measure the endothermic peak of the melting point of the obtained polyester A ′ using a differential scanning calorimeter. As a result, a sharp peak that could be determined to be an absorption peak at the melting point could not be confirmed. Further, the softening point T of polyester A '_1/2Is 108 ° C, glass transition point T_gIs 58 ° C. and the weight average molecular weight Mw is 1.5 × 10⁴Met.
[0225]
[1.3] Manufacture of polyester B (block polyester)
In a 2 liter four-necked flask, a reflux condenser, a distillation tower, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer were installed in a conventional manner, and polyester A obtained in [1.1] above: 70 1,4-butanediol as a diol component: mixture of 15 mol parts and dimethyl terephthalate as a dicarboxylic acid component: 15 g, esterification condensation catalyst (titanium tetrabutoxide (PPB)): 1 g was placed in the 2 liter 4 neck flask. Thereafter, the esterification reaction was allowed to proceed at a material temperature of 200 ° C. while water and methanol produced were allowed to flow out of the distillation tower. When water and methanol no longer flowed out of the distillation column, the distillation column was removed from the 2-liter four-necked flask and connected to a vacuum pump. With the pressure in the system reduced to 5 mmHg or less, the temperature was set to 220 ° C., and the stirring rotation speed: 150 rpm, the free diol generated in the condensation reaction was discharged out of the system, and the resulting reaction product Was polyester B (PES-B).
[0226]
Center value T of the endothermic peak of the melting point of polyester B as measured using a differential scanning calorimeter_mpIs 218 ° C, shoulder peak value T_msWas 205 ° C. Further, from the differential scanning calorimetry curve obtained from the measurement, the heat of fusion E of polyester B determined was obtained._fWas 18 mJ / mg. Also, the softening point T of polyester B_1/2Is 149 ° C., glass transition point T_gIs 64 ° C. and the weight average molecular weight Mw is 2.8 × 10⁴Met.
[0227]
[1.4] Manufacture of polyester C (block polyester)
In a 2 liter four-necked flask, a reflux condenser, a distillation tower, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer were installed in a conventional manner, and polyester A obtained in [1.1] above: 90 1,4-butanediol as a diol component: a mixture of 5 mol parts and dimethyl terephthalate as a dicarboxylic acid component: 5 g of an esterification condensation catalyst (titanium tetrabutoxide (PPB)): 1 g was placed in the 2 liter 4 neck flask. Thereafter, the esterification reaction was allowed to proceed at a material temperature of 180 ° C. while the generated water and methanol were allowed to flow out of the distillation tower. When water and methanol no longer flowed out of the distillation column, the distillation column was removed from the 2-liter four-necked flask and connected to a vacuum pump. With the pressure in the system reduced to 5 mmHg or less, the temperature was set to 200 ° C., and the stirring rotation speed: stirring at 150 rpm, the free diol generated in the condensation reaction was discharged out of the system, and the resulting reaction product Was polyester C (PES-C).
[0228]
Center value T of the endothermic peak of the melting point of polyester C as measured with a differential scanning calorimeter_mpIs 195 ° C., shoulder peak value T_msWas 182 ° C. Further, from the differential scanning calorimetry curve obtained by the measurement, the heat of fusion E of polyester C obtained was determined._fWas 8 mJ / mg. Also, the softening point T of polyester C_1/2Is 120 ° C., glass transition point T_gIs 63 ° C. and the weight average molecular weight Mw is 2.5 × 10⁴Met.
[0229]
[1.5] Manufacture of polyester D (highly crystalline polyester, not block polyester)
In a 2-liter four-necked flask, a reflux condenser, a distillation tower, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer were installed according to a conventional method, and 1,4-butanediol as a diol component: 50 parts by mole 1000 g of a mixture of dimethyl terephthalate as a dicarboxylic acid component: 60 mol parts and 1 g of an esterification condensation catalyst (titanium tetrabutoxide (PPB)) were placed in the 2-liter four-necked flask. Thereafter, the esterification reaction was allowed to proceed at a material temperature of 260 ° C. while water and methanol produced were allowed to flow out of the distillation tower. When water and methanol no longer flowed out of the distillation column, the distillation column was removed from the 2-liter four-necked flask and connected to a vacuum pump. With the pressure in the system reduced to 5 mmHg or less, the temperature was set to 280 ° C., and the stirring rotation speed: stirring at 150 rpm, the free diol generated in the condensation reaction was discharged out of the system, and the resulting reaction product Was polyester D (PES-D).
[0230]
Center value T of the endothermic peak of the melting point of polyester D measured with a differential scanning calorimeter_mpIs 228 ° C, shoulder peak value T_msWas 215 ° C. Further, from the differential scanning calorimetry curve obtained by the measurement, the melting heat E of the polyester D obtained was determined._fWas 35 mJ / mg. Also, the softening point T of polyester D_1/2Is 180 ° C, glass transition point T_gIs 70 ° C. and the weight average molecular weight Mw is 2.0 × 10⁴Met.
[0231]
In addition, the measurement of melting | fusing point, softening point, glass transition point, and weight average molecular weight about each said resin material was performed as follows.
Melting point T_mWas measured as follows using a differential scanning calorimeter DSC (DSC220 type, manufactured by Seiko Denshi Kogyo Co., Ltd.). First, the resin sample was heated to 200 ° C. at a rate of temperature increase: 10 ° C./min, and then decreased to 0 ° C. at a rate of temperature decrease: 10 ° C./min. Thereafter, the temperature is increased at a rate of temperature increase of 10 ° C./minute, and the maximum endothermic peak temperature (at the time of 2nd run) due to crystal melting at that time is expressed as_mAs sought.
[0232]
Softening point T_1/2Was measured using a capillary rheometer (manufactured by Shimadzu Corporation, flow tester CFT-500 type). Sample amount: 1 g, die hole diameter: 1 mm, die length: 1 mm, load: 20 kgf, preheating time: 300 seconds, measurement start temperature: 50 ° C., heating rate: 5 ° C./min The temperature (1/2 method temperature) when the fluctuation range of the piston stroke between the start point and the end point of the outflow is ½ is the softening point T._1/2(See FIG. 3).
[0233]
Glass transition point T_gThe measurement of was carried out simultaneously with the measurement of the melting point using a differential scanning calorimeter DSC (Seiko Denshi Kogyo Co., Ltd., DSC220 type). The tangent of the maximum differential value (maximum slope point of DSC data) between two points of the baseline designated point before and after the glass transition at the 2nd run described in the above melting point measurement method, and the extension of the baseline before the glass transition The point of intersection with the line is the glass transition point T_gAs sought.
[0234]
The weight average molecular weight Mw was measured using gel permeation chromatography GPC (manufactured by Tosoh Corporation, model HLC-8220) as follows.
First, 1 g of a resin sample was dissolved in THF (tetrahydrofuran) to obtain 1 mL of a THF solution (including insoluble matter). This THF solution was poured into a sample bottle dedicated to centrifugation, centrifuged at 2000 ppm for 5 minutes in a centrifuge, and filtered through the supernatant liquid sample prep LCR13-LH (pore size: 0.5 μm). A filtrate was obtained.
The filtrate thus obtained was subjected to gel permeation chromatography GPC (manufactured by Tosoh Corporation) under the conditions of column: TSKgel SuperHZ4000 + SuperHZ4000 (manufactured by Tosoh Corporation), flow rate: 0.5 mL / min, temperature: 25 ° C., solvent: THF. HLC-8220 type), and the weight average molecular weight Mw of the resin sample was determined based on the resulting chart. Note that monodisperse polystyrene was used as the standard sample.
[0235]
[2] Manufacture of toner
A toner was manufactured as follows.
Example 1
First, 60 parts by weight of polyester A as an amorphous polyester and 40 parts by weight of cyan pigment (PR 15: 3) as a colorant were prepared.
Each of these components was mixed using a 20 L type Henschel mixer to obtain a first raw material.
[0236]
The first raw material thus obtained was kneaded using a kneader as shown in FIG. 1 to obtain a first kneaded product (first kneading step).
In the first kneading step, the temperature in the barrel T_K1: 120 ° C., head portion temperature: 120 ° C., screw rotation speed: 120 rpm, material (first raw material) supply rate: 10 kg / h.
The first kneaded product obtained by the first kneading step was extruded from the extrusion port of the head part, cooled with a cooler, and then coarsely pulverized to an average particle size of 1 to 2 mm by a feather mill (see FIG. 1). .
[0237]
The powdery first kneaded material obtained as described above: 10 parts by weight of the second raw material (polyester A: 58 parts by weight, polyester as a block polyester, using a kneader as shown in FIG. B: 28 parts by weight, kneaded with chromium salicylate complex (Bontron E-81): 1 part by weight as a charge control agent, and carnauba wax: 3 parts by weight as a wax, to obtain a second kneaded product (first 2 kneading step).
[0238]
In the second kneading step, the barrel internal temperature T_K2: 120 ° C., head internal temperature: 110 ° C., screw rotation speed: 120 rpm, material (mixture of first kneaded material and second raw material) supply rate: 20 kg / h.
The 2nd kneaded material obtained by the 2nd kneading | mixing process was extruded from the extrusion port of the head part, and was cooled with the cooler (refer FIG. 1).
[0239]
The second kneaded product cooled as described above was coarsely pulverized (average particle size: 1 mm or less), and then finely pulverized. A feather mill was used for coarse pulverization of the kneaded product, and a jet mill (200 AFG manufactured by Hosokawa Micron Corporation) was used for fine pulverization. The fine pulverization was performed under the conditions of pulverization air pressure: 500 kPa and rotor rotation speed: 7000 rpm.
The pulverized product thus obtained was classified with an air classifier (manufactured by Hosokawa Micron Corporation, 100 ATP).
[0240]
The cooling rate of the second kneaded product was −7 ° C./second. In addition, the time required from the end of the kneading process to the end of the cooling process was 10 seconds.
Thereafter, the classified pulverized product (powder for toner production) was subjected to a thermal spheronization treatment. The thermal spheronization treatment was performed using a thermal spheronization apparatus (Nippon Pneumatic Co., Ltd., SFS3 type). The temperature of the atmosphere during the heat spheronization treatment was 270 ° C.
[0241]
Thereafter, an external additive was applied to the powder subjected to the thermal spheronization treatment to obtain a toner. The application of the external additive was performed by mixing 100 parts by weight of the powder subjected to the thermal spheroidizing treatment and 2.5 parts by weight of the external additive using a 20 L type Henschel mixer. As external additives, negatively chargeable small particle size silica (average particle size: 12 nm): 1 part by weight, negatively chargeable large particle size silica (average particle size: 40 nm): 0.5 part by weight, rutile anatase A type of titanium oxide (substantially spindle shape, average major axis diameter: 30 nm): 1 part by weight was used. In addition, as the negatively chargeable silica (negatively chargeable small particle size silica, negatively chargeable large particle size silica), those subjected to surface treatment (hydrophobization treatment) with hexamethyldisilazane were used. In addition, as the rutile-anatase type titanium oxide, the ratio of the rutile-type titanium oxide crystal structure to the anatase-type titanium oxide is 90:10 and absorbs light in the wavelength region of 300 to 350 nm. Things were used.
[0242]
However, in the production of the toner as described above, the change rate of the weight average molecular weight of each resin material before and after the production is within ± 10%, and the change amount of the melting point, the softening point, and the glass transition point is within ± 10 ° C. The conditions were as follows.
The average particle size of the finally obtained toner was 7.5 μm. The obtained toner had an average circularity R of 0.94. The acid value of the toner was 0.8 KOH mg / g. The average length of the crystals in the toner was 400 nm. Further, the coverage of the external additive in the obtained toner was 160%. The ratio (release rate) of the rutile-anatase-type titanium oxide contained in the toner as a free external additive was 1.6%.
[0243]
The circularity was measured in a water dispersion system using a flow type particle image analyzer (manufactured by Sysmex Corporation, FPIA-2000). However, the circularity R is represented by the following formula (I).
R = L₀/ L₁... (I)
(However, in the formula, L₁[Μm] is the peripheral length of the projected image of the toner particles to be measured, L₀[Μm] represents the circumference of a perfect circle having an area equal to the area of the projected image of the toner particles to be measured. )
Further, the average length of the crystals in the toner was obtained from the result of measurement using a transmission electron microscope (TEM).
[0244]
(Example 2)
A toner was produced in the same manner as in Example 1 except that polyester C was used as the block polyester and positively charged silica (average particle size: 40 nm): 1 part by weight was used as the external additive. The positively chargeable silica was obtained by subjecting negatively chargeable silica to a surface treatment (hydrophobization treatment) using an amino group-containing silane coupling agent (aminosilane).
[0245]
(Examples 3 and 4)
The composition of the raw material used for the first kneading step (first raw material) and the raw material used for the second kneading step (second raw material, first kneaded product) is as shown in Table 1, and the external addition step A toner was produced in the same manner as in Example 1 except that the type and amount of the external additive used in 1 were as shown in Table 1. Further, for Example 3, the second kneading step is performed at the temperature T in the barrel._K2: 150 ° C., head part temperature: 110 ° C., screw rotation speed: 80 rpm, material (mixture of first kneaded material and second raw material) supply rate: 20 kg / h.
[0246]
(Examples 5 and 6)
Instead of polyester A, using polyester A ′, the composition of the raw material used for the first kneading step (first raw material) and the raw material used for the second kneading step (second raw material, first kneaded product) A toner was manufactured in the same manner as in Example 1 except that the type and amount of the external additive used in the external addition step were as shown in Table 1 and as shown in Table 1.
(Examples 7 to 9)
As a kneading machine, the one shown in FIG. 18 was used, and the first kneading step and the second kneading step were performed continuously in the same manner as in Examples 1, 3, and 5, Each toner was manufactured.
[0247]
(Comparative Example 1)
A toner was produced in the same manner as in Example 1 except that the polyester B contained in the second raw material was changed to the polyester A.
(Comparative Example 2)
A toner was produced in the same manner as in Example 1 except that the polyester A contained in the second raw material was changed to the polyester B in the first raw material.
[0248]
(Comparative Example 3)
A toner was produced in the same manner as in Example 1 except that polyester D was used instead of polyester B contained in the second raw material.
(Comparative Example 4)
First, 60 parts by weight of polyester D and 40 parts by weight of cyan pigment (PR 15: 3) as a colorant were prepared.
Each of these components was mixed using a 20 L type Henschel mixer to obtain a first raw material.
[0249]
The first raw material thus obtained was kneaded using a kneader as shown in FIG. 1 to obtain a first kneaded product (first kneading step).
In the first kneading step, the temperature in the barrel T_K1: 190 ° C, head internal temperature: 190 ° C, screw rotation speed: 120 rpm, material (first raw material) supply rate: 10 kg / h.
The first kneaded product obtained by the first kneading step was extruded from the extrusion port of the head part, cooled with a cooler, and then coarsely pulverized to an average particle size of 1 to 2 mm by a feather mill (see FIG. 1). .
[0250]
The powdery first kneaded material obtained as described above: 10 parts by weight of the second raw material (polyester A: 58 parts by weight, polyester D: 28 using a kneader as shown in FIG. A second kneaded product was obtained by kneading with 1 part by weight of a chromium salicylate complex (Bontron E-81) as a charge control agent and 1 part by weight of carnauba wax as a wax (second kneading). Process).
[0251]
In the second kneading step, the barrel internal temperature T_K2: 150 ° C., head portion temperature: 140 ° C., screw rotation speed: 120 rpm, material (mixture of first kneaded material and second raw material) supply rate: 20 kg / h.
The 2nd kneaded material obtained by the 2nd kneading | mixing process was extruded from the extrusion port of the head part, and was cooled with the cooler (refer FIG. 1).
[0252]
The cooling rate of the second kneaded product was −7 ° C./second. In addition, the time required from the end of the kneading process to the end of the cooling process was 10 seconds.
Thereafter, the second kneaded product obtained as described above was subjected to pulverization, classification, thermal spheronization and external addition in the same manner as in Example 1 to produce a toner.
[0253]
(Comparative Examples 5 and 6)
A toner (colorless toner) was produced in the same manner as in Examples 1 and 4 except that the first raw material was a material containing no colorant.
[0254]
Constituent components of the toners of the respective Examples and Comparative Examples are shown in Table 1, and the average particle diameter, average circularity R, acid value, average length of crystals in the toner, coverage of external additives, Table 2 summarizes the liberation rate of rutile-anatase type titanium oxide. In the table, polyester A, polyester A ', polyester B, polyester C, and polyester D are indicated by PES-A, PES-A', PES-B, PES-C, and PES-D, respectively.
[0255]
In addition, the toner of each example and each comparative example was observed using a transmission electron microscope (TEM). As a result, for the toner of each example and the toners of Comparative Examples 5 and 6, the first region mainly composed of block polyester and the second region mainly composed of amorphous polyester were phase separated ( In particular, it was confirmed that the toners of Examples 1 to 9 existed by microphase separation. In the toners of Comparative Examples 3 and 4, it was confirmed that the region mainly composed of crystalline polyester (polyester D) and the region mainly composed of amorphous polyester existed by microphase separation. It was done. The average particle size of the first region in the toner particles measured by the observation as described above is a value in the range of 0.05 to 1.0 μm for any of the toners of Examples 1 to 9. Met. In addition, from the observations as described above, it was confirmed that in the toners of Examples and Comparative Example 3, the colorant was unevenly distributed in a region (second region) mainly composed of amorphous polyester. In the toner of Comparative Example 4, the colorant was unevenly distributed in a region (first region) mainly composed of crystalline polyester.
[0256]
For the toners of Examples and Comparative Examples 3 and 4, the toner particles are thinly sliced with a microtome, and the phase separation state between the first region and the second region is observed with a TEM (transmission electron microscope). did. Further, from the size and number of the colorant observed with a TEM (transmission electron microscope), the concentration of the colorant in the first region and the second region (C₁[Vol%] and C₂[Vol%]), and from these results, C₁/ C₂The value of was obtained. In Comparative Examples 3 and 4, the region mainly composed of polyester D was regarded as the first region.
[0257]
For the toners of the examples and comparative examples, Δt = 0.05 [seconds], and the relaxation elastic modulus G of the toner at 0.01 seconds is the initial relaxation elastic modulus G (0.01) [Pa]. Further, the ratio of G (0.01) [Pa] to G (Δt) [Pa] when the relaxation elastic modulus G (Δt) [Pa] of the toner is Δt seconds, G (0.01) / G (Δt) was determined as follows.
First, about 1 g of toner was sandwiched between parallel plates and melted by heating to prepare a height of 1.0 to 2.0 mm. The samples thus obtained were subjected to viscoelasticity measurement under the following measurement conditions in the stress relaxation measurement mode using an ARES viscoelasticity measuring apparatus (manufactured by Rheometric Scientific F.E.).
・ Measurement temperature: 150 ° C.
-Strain applied amount: Maximum strain in the wire diameter region
・ Geometry: Parallel plate (25mm diameter)
According to the above measurement, the initial relaxation elastic modulus (relaxation elastic modulus at 0.01 seconds): G (0.01) [Pa], relaxation elastic modulus at Δt = 0.05 seconds: G (Δt) [ Pa] was determined. The values of G (0.01) / G (Δt) obtained from these results are also shown in Table 2.
[0258]
[Table 1]

[0259]
[Table 2]

[0260]
[3] Evaluation
Each toner obtained as described above was evaluated for a good fixing area, development durability, storage stability, charging characteristics, transfer efficiency, and transparency.
[3.1] Good fixing range
First, a fixing device as shown in FIGS. 7 to 14 and 17 was manufactured. In this fixing device, the time Δt required for the toner to pass through the nip portion was set to 0.05 seconds. Using this fixing device, an image forming apparatus (color printer) as shown in FIGS. 5 and 6 was produced. An unfixed image sample was collected using this image forming apparatus, and the following test was performed with the fixing device of the image forming apparatus. In addition, the solid amount of the sample to be collected has an adhesion amount of 0.40 to 0.50 mg / cm.²Adjusted. In the state where the surface temperature of the fixing roller of the fixing device constituting the image forming apparatus is set to a predetermined temperature, a paper (high quality plain paper manufactured by Seiko Epson Corporation) on which the unfixed toner image is transferred is placed inside the fixing device. By introducing the toner image, the toner image was fixed on the paper, and it was visually confirmed whether or not an offset occurred after fixing.
[0261]
Similarly, the set temperature of the surface of the fixing roller is sequentially changed within a range of 100 to 250 ° C., and the presence or absence of occurrence of an offset at each temperature is confirmed. It was determined as “range” and evaluated according to the following three-stage criteria.
(Double-circle): The width | variety of a favorable fixing area is 60 degreeC or more.
○: The width of the good fixing region is 35 ° C. or more and less than 60 ° C.
X: The width of the good fixing region is less than 35 ° C.
[0262]
[3.2] Development durability
After setting 30 g of toner in the developing device of the image forming apparatus used in [3.1], aging is performed without replenishment, and the time until filming on the developing roller occurs is measured. The evaluation was performed according to the criteria.
(Double-circle): Even if 120 minutes or more passed after aging start, generation | occurrence | production of filming was not recognized.
○: Filming occurs 60 to 120 minutes after the start of aging.
X: Filming occurs in less than 60 minutes after the start of aging.
[0263]
[3.3] Preservability
The toner of each Example and each Comparative Example was placed in a sample bottle in an amount of 10 g, left in a thermostat at 50 ° C. for 48 hours, and then visually checked for the presence of lumps (aggregation). It evaluated according to.
A: The presence of lumps (aggregation) was not recognized at all.
○: A small lump (aggregation) was slightly observed.
X: A lump (aggregation) was clearly recognized.
[0264]
[3.4] Charging characteristics
In the image forming apparatus used in the above [3.1], the image forming apparatus is stopped in the middle of printing, the cartridge is removed, and the charge amount is measured using a powder charge amount distribution measuring device (E-spart analyzer, manufactured by Hosokawa Micron). The distribution was measured, and from the result, the positive charge amount was obtained as the charge amount and the reverse charge amount.
As for the charge amount, the initial charge amount and the charge amount after printing 1,000 sheets (after 1K) were obtained.
[0265]
The amount of charge after printing 1,000 sheets (after 1K) was evaluated according to the following four criteria.
A: The amount of change (absolute value) from the initial charge amount is less than 0.5 μC / g.
A: The amount of change (absolute value) from the initial charge amount is 0.5 μC / g or more and less than 1 μC / g.
Δ: The amount of change (absolute value) from the initial charge amount is 1 μC / g or more and less than 3 μC / g.
X: The amount of change (absolute value) from the initial charge amount is 3 μC / g or more.
For reversely chargeable toner, the existence ratio with respect to the total toner amount is obtained. If the existence ratio of the reverse chargeability toner is less than 3 wt%, the existence ratio of the reverse chargeability toner is 3 wt% or more. Is x.
[0266]
[3.5] Transfer efficiency
Evaluation was performed as follows using the image forming apparatus used in [3.1].
The toner on the photoconductor immediately after the development process (before transfer) to the photoconductor (image carrier) and the toner on the photoconductor after transfer (after printing) are collected using separate tapes. The weight was measured. The toner weight on the photoreceptor before transfer is expressed in W_b[G] The weight of toner on the photoreceptor after transfer is expressed as W_aWhen [g], (W_b-W_a) × 100 / W_bWas determined as the transfer efficiency.
[0267]
[3.6] Transparency
First, a small amount of toner was inserted between two slide glasses, melted on a hot plate, and then slowly cooled. The resin constituting the toner is allowed to stand until it is completely solidified, and then the HAZE value is measured with a HAZE meter (Model 1001DP manufactured by Nippon Denshoku Industries Co., Ltd.). Were evaluated as x. The HAZE value is a value obtained by dividing the diffuse transmittance by the total transmittance. The better the dispersibility of each component in the toner, the smaller the value.
These results are summarized in Table 3.
[0268]
[Table 3]

[0269]
As apparent from Table 3, the toners of the present invention were all excellent in development durability and exhibited excellent fixability in a wide temperature range. Further, the toner of the present invention was excellent in storage stability. In particular, the toner of the present invention exhibits excellent development durability, fixability, and storage stability while maintaining charging characteristics, transfer efficiency, and transparency. Particularly excellent results were obtained with the toners of Examples 1, 2, 4, and 7 in which the composition of block polyester and amorphous polyester is preferable, and the average particle size of the first region is optimal. It was.
[0270]
On the other hand, with the toner of the comparative example, sufficient characteristics could not be obtained.
In particular, the toner of Comparative Example 1 containing no block polyester was weak against mechanical stress and particularly inferior in development durability and storage stability.
Further, the toner of Comparative Example 2 containing no amorphous polyester had low fixing strength and poor fixing properties. Further, the toner of Comparative Example 2 was inferior in transparency.
[0271]
In addition, the toners of Comparative Examples 3 and 4 in which amorphous polyester and highly crystalline polyester D are used in combination without using block polyester have an affinity between resins (affinity between block polyester and crystalline polyester). In other words, macrophase separation occurred in the toner particles, and the fixability and durability were particularly inferior.
Further, in Comparative Example 4 where the colorant is unevenly distributed in the first region, the durability was particularly low.
[0272]
Further, the toners of Comparative Examples 5 and 6 containing no colorant had relatively excellent development durability, but both were inferior to the toners of Examples 1 to 9. From this, by making the colorant unevenly distributed in the second region mainly composed of amorphous polyester as in the present invention (regardless of the blending ratio of block polyester and amorphous polyester, It can be seen that the effect of improving the durability of the toner is obtained.
[0273]
Further, each toner was passed through the nip portion of the fixing device, and the change amount of the relaxation elastic modulus G (t) in the passage time Δt [seconds] of the toner particles through the nip portion was measured. In each of the toners 1 to 9, the amount of change in the relaxation elastic modulus G (t) was 100 [Pa] or less. The temperature of the nip portion when the toner particles pass was 180 ° C.
[0274]
Further, as a colorant, quinacridone (PR 122), Pigment Red 57: 1, C.I. I. Except for using Pigment Yellow 93 and Carbon Black, toners were prepared in the same manner as in the above Examples and Comparative Examples, and the same evaluations were performed on these toners. As a result, the same results as those of the respective Examples and Comparative Examples were obtained.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view schematically showing an example of the configuration of a kneader and a cooler used in a first embodiment of a toner production method of the present invention.
FIG. 2 is a model diagram of a differential scanning calorimetry curve in the vicinity of the melting point of the block polyester obtained when differential scanning calorimetry is performed on the block polyester.
FIG. 3 is a flowchart for softening point analysis.
FIG. 4 is a diagram for explaining a method of measuring the amount of rutile-anatase type titanium oxide released from toner particles contained in the toner.
FIG. 5 is an overall configuration diagram illustrating a preferred embodiment of an image forming apparatus of the present invention (an image forming apparatus to which the toner of the present invention is preferably applied).
6 is a cross-sectional view of a developing device included in the image forming apparatus of FIG.
7 is a perspective view showing a detailed structure of the fixing device of the present invention used in the image forming apparatus of FIG.
FIG. 8 is a cross-sectional view of a main part of the fixing device of FIG.
FIG. 9 is a perspective view of a peeling member constituting the fixing device of FIG.
10 is a side view showing a mounting state of a peeling member constituting the fixing device of FIG. 7; FIG.
FIG. 11 is a front view of the fixing device of FIG. 7 as viewed from above.
FIG. 12 is a schematic diagram for explaining an arrangement angle of a peeling member with respect to a tangent at an exit of a fixing nip portion.
FIG. 13 is a diagram schematically illustrating the shape of a fixing roller and a pressure roller, and the shape of a fixing nip portion.
14 is a cross-sectional view taken along line XX in FIG. 13 (a).
FIG. 15 is a diagram schematically illustrating the shape of a fixing roller and a pressure roller, and the shape of a fixing nip portion.
16 is a cross-sectional view taken along line YY in FIG.
FIG. 17 is a cross-sectional view for explaining a gap between the fixing roller and the peeling member.
FIG. 18 is a longitudinal sectional view schematically showing an example of the configuration of a kneader and a cooler used in the second embodiment of the toner production method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 1 '... Kneading machine 12 ... Process part 121 ... Barrel 122, 123 ... Screw 124 ... Fixing member 13 ... Head part 131 ... Internal space 132 ... Extrusion port 133 ... Cross-sectional area gradually decreasing part 14 …… Feeder 2 …… First kneading part 21 …… Feeder 22 …… Processing part 221 …… Barrel
222, 223 ... Screw 3 ... Second kneading part 31 ... Feeder 32 ... Process part 321 ... Barrel 322, 323 ... Screw 324 ... Fixing member 4 ... Connection part 5 ... Head part 51 ... ... Internal space 52 ... Extrusion port 53 ... Cross-sectional area gradually decreasing part 6 ... Cooling device 61, 62, 63, 64 ... Roll 611, 621, 631, 641 ... Rotating shaft 65, 66 ... Belt
67 …… Discharge section 7 …… First raw material 8 …… First kneaded material 9 …… Second raw material
DESCRIPTION OF SYMBOLS 10 ... 2nd kneaded material 1000 ... Image forming apparatus 20 ... Apparatus main body 30 ... Image carrier 40 ... Charging apparatus 50 ... Exposure apparatus 60 ... Rotary developing apparatus 600 ... Support frame 601 ... Housing 603 ... Supply roller
604... Developing roller 605... Restricting blade 605 a .. Plate member 605 b .. Elastic member 60 Y... Yellow developing device 60 M... Magenta developing device 60 C. …… Intermediate transfer device 90 …… Drive roller 100 …… Drive roller 110 …… Intermediate transfer belt 120 …… Primary transfer roller 130 ...... Transfer belt cleaner 140 …… Secondary transfer roller 150 …… Paper feed cassette 160 …… Pickup Roller 170... Recording medium transport path 190... Fixing device 200 .. Discharge tray 210... Fixing roller (heat fixing member) 210 a.
210c: Elastic layer 210d: Rotating shaft 220: Pressure roller (pressure member)
220b …… Cylinder 220c …… Elastic layer 220d …… Rotating shaft 230 …… Double-sided printing conveyance path 240 …… Housing 250 …… Bearing 260 …… Pressure lever 270 …… Pressure spring 280 …… Drive gear 290… … Support shaft 300 …… support shaft 310 …… peeling member 310a …… peeling portion 310b …… folded portion
310c …… Supporting piece 310d …… Fitting hole 310e …… Guide part 310f …… Tip part 320 …… Peeling member 320a …… Peeling part 320e …… Guide part
330 ... Spring 340 ... Fixing nip (nip) 341 ... Nip outlet 500 ... Recording medium T ... Toner S ... Tangent G1 ... Gap
G2: Gap

Claims (8)

A method for producing a toner composed of a material containing a polyester resin and a colorant,
The polyester resin includes a block polyester mainly composed of a block copolymer, and an amorphous polyester having lower crystallinity than the block polyester.
The block polyester has a crystalline block formed by condensing an alcohol component and a carboxylic acid component, and an amorphous block having lower crystallinity than the crystalline block,
A first kneading step for producing a first kneaded product containing the amorphous polyester and the colorant;
At least, it possesses a first kneaded product, and kneaded material containing the block polyester, and a second kneading step of producing a second kneaded product,
The softening point of the amorphous polyester is T _1/2 (A) [° C.], the melting point of the block polyester is T _m (B) [° C.], and the material temperature during the second kneading step is T _K2 [° C. ], A toner production method characterized by satisfying a relationship of T _m (B)> T _K2 > T _1/2 (A) . A method for producing a toner composed of a material containing a polyester resin and a colorant,
The polyester resin includes a block polyester mainly composed of a block copolymer, and an amorphous polyester having lower crystallinity than the block polyester.
The block polyester has a crystalline block formed by condensing an alcohol component and a carboxylic acid component, and an amorphous block having lower crystallinity than the crystalline block,
A first kneading step for producing a first kneaded product containing the amorphous polyester and the colorant;
At least a second kneading step of kneading a material containing the first kneaded material and the block polyester to produce a second kneaded material,
The softening point of the amorphous polyester is T _1/2 (A) [° C.], the melting point of the block polyester is T _m (B) [° C.], and the material temperature during the second kneading step is T _K2 [° C. ], The relationship of T _m (B)> T _K2 > T _1/2 (A) is satisfied,
Forming a first region mainly composed of the block polyester and a second region mainly composed of the amorphous polyester;
A method for producing a toner, comprising producing a toner in which the concentration of the colorant in the second region is higher than the concentration of the colorant in the first region. 3. The toner manufacturing method according to claim 1, wherein a material temperature in the first kneading step is 80 to 160 ° C. 4. 4. The toner manufacturing method according to claim 1, wherein a material temperature in the second kneading step is 80 to 260 ° C. 5. The method for producing a toner according to claim 1, wherein the first kneading step and the second kneading step are continuously performed. A first kneading section for performing the first mixing step, and a second kneading section that performs second mixing step, according to any one of claims 1 to 5 using a two-stage barrel-type kneader Toner production method. Pulverizing and classifying the second kneaded product to obtain a toner production powder;
The method for producing a toner according to claim 1, further comprising a thermal spheronization step in which the powder for toner production is heated to spheroidize. The toner manufacturing method according to any one of claims 1 to 7 , wherein the temperature of the atmosphere during the thermal spheronization step is 210 to 320 ° C.

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