JP4244641B2 - Toner and image forming method - Google Patents

Description

【０２５０】
【表２】

【０２５１】
【表３】

【０２５２】
【表４】

【０２５３】
［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。
【０２５４】
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。
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。
【０２５５】
［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。
【０２５６】
［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。
【０２５７】
［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、室温条件（２５℃湿度４５％）での初期帯電量、１０００枚印字後（１Ｋ後）の帯電量、および高温高湿条件下(３０℃湿度８５％)での帯電量について求めた。
【０２５８】
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。
【０２５９】
［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。
これらの結果を表５および表６にまとめて示した。
【０２６０】
【表５】

【０２６１】
【表６】

【０２６２】
表５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、帯電特性にも優れていた。特に本発明のトナーでは、転写効率を保持しつつ、優れた現像耐久性、定着性、保存性、帯電特性を発揮するものであった。また、ポリエステル系樹脂の組成や、正帯電性シリカの平均粒径、遊離外添剤の割合が好ましい範囲のトナーでは、極めて良好な結果が得られた。
【０２６３】
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、正帯電性シリカを含まない比較例１のトナーでは、１０００枚印字後の帯電量変化や逆帯電量が特に大きく、帯電特性に劣っていた。
また、トナーの酸価が８．０ＫＯＨｍｇ／ｇよりも高い比較例２〜６のトナーは、高温高湿下での帯電量低下が著しく激しかった。
特に、ポリエステル系樹脂を構成するジオール成分として芳香族ジオールを用いた比較例５のトナーは、樹脂の摩擦係数が大きいため、耐久性に劣っていた。
【０２６４】
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１〜８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。
【０２６５】
また、着色剤として、キナクリドン（Ｐ．Ｒ．１２２）に代わり、銅フタロシアニン顔料、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に用いる混練機、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正帯電性シリカ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】 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、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、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。
【符号の説明】
１……混練機 ２……プロセス部 ２１……バレル ２２、２３……スクリュー ２４……固定部材 ３……ヘッド部 ３１……内部空間 ３２……押出口 ３３……横断面積漸減部 ４……フィーダー ５……原料 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……混練物 １０……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……記録媒体搬送経路 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……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 invention relates to a toner,And image forming 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.
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.
[0003]
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.
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.
[0004]
There is also known a toner using a polyester-based resin composed of an aliphatic diol without using an aromatic diol such as bisphenol A (see, for example, Patent Document 2). This is a polyester resin obtained by condensing a monomer composition containing a trivalent or higher polyvalent monomer, an aliphatic diol, and an aromatic dicarboxylic acid. However, such a toner has a problem that a temperature range in which sufficient fixability (fixing strength) can be secured becomes narrow.
[0005]
In addition, a toner using an aromatic diol such as bisphenol A has a relatively large triboelectric chargeability. Therefore, when such a toner is used, the charge amount can be made relatively large. However, a toner using a polyester resin composed of an aliphatic diol without using an aromatic diol such as bisphenol A has a relatively small coefficient of friction and it is difficult to increase the charge amount. . Therefore, it is also known to increase the acid value of the resin constituting the toner in order to increase the charge amount of the toner (see, for example, Patent Document 3). However, such a toner has a problem that environmental characteristics (particularly moisture resistance) of the toner are lowered, and variation in charging between the toner particles is increased.
[0006]
[Patent Document 1]
JP 57-109825 A (page 1, lines 1 to 27)
[Patent Document 2]
Japanese Patent No. 2704282 (first page, lines 9 to 10)
[Patent Document 3]
Japanese Patent No. 3065073 (page 1, lines 3-4)
[0007]
[Problems to be solved by the invention]
  An object of the present invention is to provide a toner having excellent environmental characteristics (particularly moisture resistance) and having stable charging characteristics, and the toner can be suitably applied.Image forming methodIs to provide.
[0008]
[Means for Solving the Problems]
  Such an object is achieved by the present invention described below.
  The negatively chargeable toner of the present invention is a toner in which the resin component is composed of a material mainly composed of a polyester resin,
  The alcohol component constituting the polyester-based resin is composed of a linear and / or cyclic aliphatic diol,
The polyester-based resin includes a block polyester 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 the alcohol component and a carboxylic acid component, and an amorphous block having lower crystallinity than the crystalline block,
  Containing positively charged silica and rutile-anatase type titanium oxide,
  The toner has an acid value of 8.0 KOHmg / g or less.
  As a result, the toner is resistant to mechanical stress, can secure a sufficient fixing property in a wide temperature range, and can be a toner excellent in storage stability, environmental characteristics, and charging characteristics.
[0009]
  In the toner of the present invention, the polyester resin is, NonA cross-linked type is preferred.
  Thereby, it is possible to ensure excellent stability against mechanical stress.
  In the toner of the present invention, the average particle diameter of primary particles of the positively chargeable silica is preferably 30 to 200 nm.
  As a result, the triboelectric chargeability is improved, and the generation of reversely chargeable toner particles during development or the like can be prevented or suppressed.
[0010]
In the toner of the present invention, the content of the positively chargeable silica in the toner is preferably 0.2 to 2.0 wt%.
As a result, it is possible to effectively prevent a decrease in fixability.
In the toner of the present invention, the positively chargeable silica is preferably obtained by treating silica gel with a silane coupling agent having an amino group.
Thereby, the improvement of the environmental characteristics and charging characteristics of the toner becomes more remarkable.
[0011]
In the toner of the present invention, the positively chargeable silica is preferably added as an external additive.
Thereby, the charging characteristics of the toner can be improved.
The toner of the present invention preferably further includes other external additives in addition to the positively chargeable silica.
Thereby, the environmental characteristics and charging characteristics of the toner can be made more remarkable.
[0012]
  In the toner of the present invention, it is preferable that negatively-charged silica is contained as the other external additive.
  Thereby, a stable negatively chargeable toner can be obtained, and toner control of the image forming apparatus becomes easy.
[0013]
In the toner of the present invention, the positively chargeable silica released from the surface of the toner particles preferably functions as a microcarrier that is charged to a polarity opposite to that of the toner particles.
As a result, it is possible to effectively prevent and suppress the generation of reversely chargeable toner particles during development or the like.
[0026]
  The image forming method of the present invention includes a fixing roller,
  A pressure roller pressed against the fixing roller;
  A fixing device having a peeling member for peeling a recording medium that has passed through a fixing nip formed by a contact portion between the fixing roller and the pressure roller from the fixing roller, the resin component is mainly a polyester resin. An image forming method for forming an image by fixing toner composed of a material to a recording medium,
  The alcohol component constituting the polyester-based resin is composed of a linear and / or cyclic aliphatic diol,
The polyester-based resin includes a block polyester 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 the alcohol component and a carboxylic acid component, and an amorphous block having lower crystallinity than the crystalline block,
  Containing positively charged silica and rutile-anatase type titanium oxide,
  The toner has an acid value of 8.0 KOHmg / g or less.
  As a result, even when the toner is fixed to the recording medium at a relatively high speed, it is possible to prevent the image from causing streaks and disturbances, and it is difficult to cause a peeling defect such as a winding of the recording medium. . In addition, since the toner contains positively-charged silica having a relatively large particle diameter, it is possible to sufficiently prevent a decrease in fixability, and further, compared to the case where other external additives are added, the mechanical stress is reduced. On the other hand, it exhibits particularly excellent stability. For this reason, such a toner can be suitably applied to the fixing device.
[0027]
  Of the present inventionWith image forming methodThe fixing device preferably has a recording medium feed speed of 0.05 to 1.0 m / sec.
  In this way, the toner can be fixed on the recording medium at a relatively high speed, and it is possible to prevent the image from causing streaks and disturbances during fixing, and also to cause peeling defects such as winding of the recording medium. Can be made difficult to occur.
[0028]
  Of the present inventionImage forming methodThen, it is preferable that the peeling member is a plate-like member having a predetermined length in the axial direction of the fixing roller and / or the pressure roller.
  Thereby, the peelability of the recording medium from the fixing roller and the pressure roller can be improved.
  Of the present inventionImage forming methodIn the fixing device, it is preferable that the peeling member is disposed downstream of the fixing nip portion in the recording medium conveyance direction.
  Thereby, the peelability of the recording medium from the fixing roller and the pressure roller can be improved.
[0029]
  Of the present inventionImage forming methodThen, it is preferable that the peeling member is disposed in the vicinity of the fixing roller and / or the pressure roller.
  Thereby, the peelability of the recording medium from the fixing roller and the pressure roller can be improved.
  Of the present inventionWith image forming methodIn the fixing device, the fixing roller and the pressure roller are preferably arranged in a substantially horizontal state.
  This prevents streaks and disturbances in the image and improves the peelability of the recording medium.
[0030]
  Of the present inventionWith image forming methodPreferably, the fixing device is provided with the peeling member so that a gap between the fixing roller and the peeling member is substantially constant during operation.
  Thereby, the fall of the peelability of a recording medium can be prevented.
  Of the present inventionImage forming methodThen, it is preferable that the peeling member is disposed along the axial direction of the fixing roller and has a shape along the shape of the outlet of the fixing nip portion.
  Thereby, the peelability of the recording medium from the fixing roller and the pressure roller can be improved.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, the toner of the present invention,And image forming methodA preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. First, the toner of the present invention will be described.
  FIG. 1 is a longitudinal sectional view schematically showing an example of the configuration of a kneader and a cooler used for producing the toner of the present invention, and FIG. 2 is a block obtained when a differential scanning calorimetric analysis is performed on a block polyester. 3 is a model diagram of a differential scanning calorimetric curve near the melting point of polyester, FIG. 3 is a flowchart for softening point analysis, and FIG. 4 is a method for measuring the amount of positively charged silica released from toner particles contained in the toner. It is a figure for demonstrating. Hereinafter, in FIG. 1, the left side is described as “base end” and the right side is described as “tip”.
  The toner of the present invention includes at least a resin as a main component (hereinafter also simply referred to as “resin”), positively-charged silica,, Rutile-anatase type titanium oxide andIs included.
[0036]
Hereinafter, an example of a constituent material and a manufacturing method of the toner of the present invention will be described.
[Constituent materials]
The toner of the present invention can be produced using a raw material 5 containing at least a resin as a main component (hereinafter also simply referred to as “resin”).
Hereinafter, each component of the raw material 5 used for manufacturing the toner of the present invention will be described.
[0037]
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.
In general, the polyester-based resin is composed of an alcohol component (including one having two or more hydroxyl groups) and a carboxylic acid component (including a divalent or higher carboxylic acid or a derivative thereof).
[0038]
As the alcohol component, those having two or more hydroxyl groups can be used, for example, ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butane. Diol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol , Neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1, 3-pentanediol, 2-ethyl-1,3-hexanediol Chain diols such as 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, or 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)- Addition of alkylene oxide of bisphenol A such as 2,2-bis (4-hydroxyphenyl) propane 2,2-bis (4-hydroxycyclohexyl) propane, 2,2-bis (4-hydroxycyclohexyl) propane alkylene oxide adduct, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, a cyclic diol such as an alkylene oxide adduct of hydrogenated bisphenol A, or 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-trihydroxyme Examples include trihydric or higher polyhydric alcohols such as tilbenzene.
[0039]
In particular, the present invention is characterized in that the alcohol component is mainly composed of an aliphatic diol having two hydroxyl groups. In addition, the alcohol component may be composed of an aliphatic alcohol having three or more hydroxyl groups. Examples of the aliphatic alcohol having two or more hydroxyl groups include ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, diethylene glycol, 1, 5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, neopentyl glycol (2 , 2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentanediol, 2 -Ethyl-1,3-hexanediol, 2-butyl-2-ethyl -1,3-propanediol, 2,4-diethyl-1,5-pentanediol, chain diols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, or 2,2-bis (4-hydroxycyclohexyl) Alkylene oxide adduct of propane, 2,2-bis (4-hydroxycyclohexyl) propane, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, hydrogenated bisphenol A alkylene oxide adduct, etc. And cyclic diols.
Thus, in the present invention, the alcohol component is mainly composed of an aliphatic diol, but 50 mol% or more thereof is preferably composed of an aliphatic diol, and 80 mol% or more thereof is a fatty diol. More preferably, it is composed of a group diol.
[0040]
As the carboxylic acid component, for example, a divalent or higher valent carboxylic acid or a derivative thereof (for example, acid anhydride, lower alkyl ester, etc.) can be used. For example, o-phthalic acid (phthalic acid), terephthalic acid, Isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octyl succinic acid, cyclohexanedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, trimellitic acid, pyromellitic acid and derivatives thereof (for example, anhydride, lower Alkyl esters and the like).
[0041]
In particular, in the present invention, the carboxylic acid component is preferably composed of a divalent dicarboxylic acid.
Examples of the divalent dicarboxylic acid 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, maleic acid. , Itaconic acid and derivatives thereof (for example, anhydrides, lower alkyl esters, etc.) and the like.
[0042]
Moreover, in this invention, it is especially preferable to use what contains block polyester and amorphous polyester which are demonstrated below as a polyester-type resin. Hereinafter, these will be described in detail.
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.
[0043]
(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 finally obtained toner maintains excellent shape stability even at a relatively high temperature (a temperature near the melting point of the block polyester) at which the amorphous polyester described later is sufficiently softened. be able to. Therefore, when such a block polyester is used, sufficient fixability (fixing strength) can be exhibited in a wide temperature range.
Further, by having such a crystalline block, it is possible to precipitate crystals having a high hardness and an appropriate size in the toner. When such a crystal exists, the stability of the shape of the toner is particularly excellent, and particularly excellent stability against mechanical stress is exhibited. In addition, when such crystals are present in the toner, an external additive as will be described later is more reliably held near the surface of the toner particles (mother particles) (the outer additive is contained in the mother particles). It is possible to effectively prevent burying) and to fully exhibit the functions of the external additive (for example, effects such as excellent fluidity and charging property).
Moreover, since such a block polyester has such a crystalline block, when such a block polyester is used, it becomes possible to perform the thermal spheroidization process mentioned later efficiently (in a short time). The circularity of the finally obtained toner particles can be made particularly excellent.
[0045]
Hereinafter, components constituting the crystalline block will be described.
As the alcohol component constituting the crystalline block, one having two or more hydroxyl groups can be used, and among them, a diol component having two hydroxyl groups is preferable. Examples of such a diol component having two hydroxyl groups include an aromatic diol having an aromatic ring structure, an aliphatic diol having no aromatic ring structure, and the like, and examples of the aromatic diol include bisphenol A. Or an alkylene oxide adduct 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) pro Examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, and diethylene glycol. 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, neopentyl Glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentane Diol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl 1,2-propanediol, 2,4-diethyl-1,5-pentanediol, chain diols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, or 2,2-bis (4-hydroxycyclohexyl) ) Alkylene oxide adduct of propane, 2,2-bis (4-hydroxycyclohexyl) propane, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, hydrogenated bisphenol A alkylene oxide adduct And the like, and the like.
[0046]
As described above, the diol 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.
[0047]
The diol 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 a diol component, the crystallinity is improved and the coefficient of friction 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.
[0048]
When 1,4-butanediol is included as the diol component constituting the crystalline block, 50 mol% or more of the diol constituting the crystalline block is more preferably 1,4-butanediol, and 80 mol% or more thereof is 1 More preferred is 4-butanediol. Thereby, the effect mentioned above becomes further remarkable.
[0049]
As the carboxylic acid component constituting the crystalline block, divalent or higher carboxylic acids or derivatives thereof (for example, acid anhydrides, lower alkyl esters, etc.) can be used, but divalent dicarboxylic acids or derivatives thereof, etc. Is preferably used. Examples of such divalent dicarboxylic 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.).
[0050]
As described above, the dicarboxylic 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.
[0051]
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 upper limit, the content of the amorphous block is relatively decreased, and therefore the compatibility between the block polyester and the amorphous polyester described later may be decreased. There is.
The crystalline block may contain components other than the alcohol component and carboxylic acid component as described above.
[0052]
(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, in general, resins having greatly different crystallinities are hardly compatible with each other, and resins having a small difference in crystallinity are easily compatible with each other. Therefore, when the block polyester has an amorphous block, compatibility (dispersibility) between the block polyester and the amorphous polyester described later is increased. As a result, it is possible to effectively prevent phase separation (particularly macrophase separation) between the block polyester and the amorphous polyester in the finally obtained toner. The advantages of polyester can be exhibited sufficiently and stably.
[0053]
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, a diol having two hydroxyl groups is preferable. Examples of such a diol component having two hydroxyl groups include an aromatic diol having an aromatic ring structure, an aliphatic diol having no aromatic ring structure, and the like, and examples of the aromatic diol include bisphenol A. And an alkylene oxide adduct of bisphenol A. Examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4. -Butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,3- Butanediol, neopentyl glycol (2 2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentanediol, 2- Chains such as ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol Diols, or 2,2-bis (4-hydroxycyclohexyl) propane, alkylene oxide adducts of 2,2-bis (4-hydroxycyclohexyl) propane, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol , Hydrogenated bisphenol A, alkylene of hydrogenated bisphenol A Kisaido adducts cyclic diols such as and the like.
[0054]
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 diol 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.
[0055]
As the carboxylic acid component constituting the amorphous block, 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 dicarboxylic 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.).
[0056]
As described above, the dicarboxylic 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.
The amorphous block may contain components other than the alcohol component and carboxylic acid component as described above.
[0057]
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 above upper limit, grain boundary breakage is liable to occur at the time of toner fixing, the wettability to a transfer material (recording medium) such as paper is reduced, and the amount of heat required for fixing is increased.
[0058]
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 of the thermal spheronization treatment as described later may not be sufficiently exhibited. The glass transition point can be measured according to JIS K7121.
[0059]
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, when the softening point exceeds the upper limit, grain boundary breakage is liable to occur during toner fixing, the wettability to a transfer material (recording medium) such as paper is reduced, and the amount of heat required for fixing is increased. 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 at a point on the flow curve corresponding to h / 2 in the flowchart for analysis as shown in FIG.
[0060]
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.
[0061]
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 (the endothermic peak of the melting point was measured by differential scanning calorimetry described later). The central 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 satisfying such a relationship, it is possible to effectively prevent toner from adhering to a fixing roller of a fixing device described later. Further, since the block polyester has the property of easily forming crystals of an appropriate size as described above, stability and durability can be maintained even after the toner is fixed on the recording medium. In particular, when the block polyester is used in combination with an amorphous polyester described later, the amorphous polyester described later can be sufficiently softened during fixing. 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.
[0062]
Moreover, it is preferable that melting | fusing point of block polyester is higher than the softening point of the amorphous polyester mentioned later. As a result, the stability of the finally obtained toner shape is improved, and particularly excellent stability against mechanical stress is exhibited. Further, when the melting point of the block polyester is higher than the softening point of the amorphous polyester described later, for example, in the thermal spheronization process described later, the block polyester ensures a certain degree of stability of the shape of the powder for toner production. Crystalline 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.
[0063]
By the way, as described above, since the block polyester has a crystalline block with high crystallinity, it is so-called sharper than a resin material with relatively low crystallinity (for example, amorphous polyester described later). Has melt properties.
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 cooled 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].
[0064]
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. Then, the value measured when the temperature is increased at a rate of temperature increase of 10 ° C./min can be obtained as the heat of fusion.
[0065]
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.
[0066]
1-2. Amorphous polyester
Amorphous polyester has lower crystallinity than the block polyester described above.
Amorphous polyester is mainly composed of the dispersibility of each component constituting the toner (for example, a colorant, wax, antistatic agent and the like as described later), the pulverization property of the kneaded product during toner production, and the toner fixing property. It is a component that contributes to improving functions such as (especially low-temperature fixability), transparency, mechanical properties (for example, elasticity, mechanical strength, etc.), chargeability, and moisture resistance. In other words, if the amorphous polyester described in detail below is not contained in the toner, it may be difficult to sufficiently exhibit the characteristics required for the toner as described above.
[0067]
Hereinafter, the components constituting the amorphous polyester will be described.
As the alcohol component constituting the amorphous polyester, one having two or more hydroxyl groups can be used, and among them, a diol having two hydroxyl groups is preferable. Examples of such a diol component having two hydroxyl groups include an aromatic diol having an aromatic ring structure and an aliphatic diol having no aromatic ring structure. Examples of the aromatic diol include bisphenol A and alkylene oxide adducts of bisphenol A. Examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1 , 3-butanediol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2 , 4-Pentanediol, 3-methyl -1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, polyethylene glycol, Chain diols such as polypropylene glycol and polytetramethylene glycol, or alkylene oxide adducts of 2,2-bis (4-hydroxycyclohexyl) propane and 2,2-bis (4-hydroxycyclohexyl) propane, 1,4- And cyclic diols such as cyclohexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, and alkylene oxide adducts of hydrogenated bisphenol A.
[0068]
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 dicarboxylic 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.).
[0069]
As described above, the dicarboxylic 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.
[0070]
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 compatibility between the block polyester and the amorphous polyester is particularly excellent. However, the “monomer component” here does not refer to a monomer used in the production of block polyester or amorphous polyester, but refers to a monomer component contained in block polyester or amorphous polyester.
The amorphous polyester may contain components other than the diol component and the dicarboxylic acid component as described above.
[0071]
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 above upper limit, grain boundary breakage is liable to occur at the time of toner fixing, the wettability to a transfer material (recording medium) such as paper is reduced, and the amount of heat required for fixing is increased.
[0072]
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 of the thermal spheronization treatment as described later may not be sufficiently exhibited. The glass transition point can be measured according to JIS K7121.
[0073]
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, when the softening point exceeds the upper limit, grain boundary breakage is liable to occur during toner fixing, the wettability to a transfer material (recording medium) such as paper is reduced, and the amount of heat required for fixing is increased.
[0074]
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. Thereby, the viscosity of the toner particles near the fixing temperature of the toner can be made relatively low, and the stress relaxation time of the toner can be lengthened. As a result, the fixability can be made particularly excellent when the toner of the present invention is used in a fixing device as described later. 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.
[0075]
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 at a point on the flow curve corresponding to h / 2 in the flowchart for analysis as shown in FIG.
[0076]
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. As a result, particularly excellent releasability is obtained, and toner transfer efficiency is further improved.
As described above, when the block polyester and the amorphous polyester are used in combination, the above-described features of the block polyester and the features of the amorphous polyester can be achieved. As a result, the toner finally obtained is resistant to mechanical stress (has sufficient physical stability) and can exhibit sufficient fixability (fixing strength) in a wide temperature range. It becomes.
[0077]
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 is too low, the synergistic effect as described above is not sufficiently exhibited, and 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, the synergistic effect as described above is not sufficiently exhibited, and sufficient low-temperature fixability and transparency may not be obtained. In addition, if the blending ratio of the amorphous polyester is too low, for example, it becomes difficult to efficiently and uniformly pulverize the kneaded product 7 in the pulverization step of the toner production method as described later. There is.
[0078]
Moreover, resin (binder resin) may contain components other than the polyester-type resin mentioned above.
Examples of the resin component (third resin component) other than the polyester resin include polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, and styrene-butadiene copolymer. Polymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylic acid ester -Styrene or styrene-substituted styrene resin such as methacrylic acid ester copolymer, styrene-α-chloroacrylic acid methyl copolymer, styrene-acrylonitrile-acrylic acid ester copolymer, styrene-vinyl methyl ether copolymer A homopolymer or copolymer, 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, A xylene resin, a polyvinyl butyral resin, a terpene resin, a phenol resin, an aliphatic or alicyclic hydrocarbon resin, and the like can be given, and one or more of these can be used in combination.
[0079]
The content of the resin in the raw material 5 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.
[0080]
2. Colorant
Examples of the colorant that can be used include pigments and dyes. 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.
[0081]
The content of the colorant in the raw material 5 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.
[0082]
3. wax
Further, the raw material 5 used for manufacturing the toner may contain a wax as necessary.
By including the wax, for example, the releasability of the toner particles can be improved.
[0083]
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.
Among the above materials, particularly when ester wax (for example, carnauba wax or rice wax) is used, the following effects can be obtained.
[0084]
The ester wax has an ester structure in the molecule and is excellent in compatibility with the polyester resin, similarly to the polyester resin described above. 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.
[0085]
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. The melting point T_mFor example, by differential scanning calorimetry (DSC), the temperature is increased to 200 ° C. at a temperature increase rate of 10 ° C./min, and further the temperature decrease rate is 10 ° C./min, and then the temperature increase rate is 10 ° C./min. The value measured when the temperature is raised at can be obtained as the heat of fusion.
[0086]
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.
[0087]
4). Other ingredients
The raw material 5 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.
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.
[0088]
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.).
[0089]
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.
[0090]
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.
[0091]
[Kneading process]
The raw material 5 as described above is kneaded using a kneader 1 as shown in FIG.
It is preferable that the raw material 5 to be kneaded is prepared by previously mixing the above-described components.
This embodiment demonstrates the structure which uses a biaxial kneading extruder as a kneading machine.
[0092]
The kneading machine 1 includes a process unit 2 for kneading while conveying the raw material 5, a head unit 3 for extruding the kneaded raw material (kneaded material 7) in a predetermined cross-sectional shape, and the raw material 5 in the process unit 2. And a feeder 4 to be supplied.
The process unit 2 includes a barrel 21, a screw 22 and a screw 23 inserted into the barrel 21, and a fixing member 24 for fixing the head unit 3 to the tip of the barrel 21.
[0093]
In the process part 2, the screw 22 and the screw 23 rotate to apply a shearing force to the raw material 5 supplied from the feeder 4, and the uniform kneaded material 7, in particular, the block polyester and the amorphous polyester are sufficient. To obtain a kneaded product 7 which is compatible with each other.
The total length of the process part 2 is preferably 50 to 300 cm, and more preferably 100 to 250 cm. If the total length of the process part 2 is less than the lower limit value, it may be difficult to sufficiently compatibilize the block polyester and the amorphous polyester. On the other hand, when the total length of the process unit 2 exceeds the upper limit, depending on the temperature in the process unit 2, the number of rotations of the screw 22 and the screw 23, the raw material 5 is easily denatured by heat, and finally obtained. It may be difficult to sufficiently control the physical properties of the toner.
[0094]
In addition, the process unit 2 includes a first region 25 having a predetermined length in the longitudinal direction, and a second region 26 provided on the head unit 3 side from the first region 25. That is, the raw material 5 is fed into the second region 26 after passing through the first region 25.
The internal temperature of the first region 25 is set higher than that of the second region 26. That is, in other words, the temperature of the raw material 5 transported inside the process unit 2 when passing through the first region 25 is higher than the temperature when passing through the second region 26.
[0095]
As described above, in the first region 25, the raw material 5 is kneaded at a relatively high temperature, so that the block polyester and the amorphous polyester can be sufficiently compatible.
Raw material temperature in the first region 25 (internal temperature of the first region 25) T₁[° C] is the melting point of the block polyester T_m(B) When [° C.], T_m(B) ≦ T₁It is preferable to satisfy the relationship of (T_m(B) + 10 ° C.) ≦ T₁≤ (T_mIt is more preferable that the relationship (B) + 60 ° C. is satisfied. Raw material temperature T₁But T_m(B) When it is less than [° C.], it may be difficult to sufficiently compatibilize the block polyester and the amorphous polyester.
[0096]
Raw material temperature T in the first region 25₁The specific value varies depending on the resin composition and the like, but is preferably 190 to 300 ° C, more preferably 200 to 250 ° C.
Further, in the first region 25, the raw material temperature T₁May be uniform or different depending on the site. In the latter case, the maximum temperature of the raw material 5 in the first region 25 is preferably higher than the lower limit value, and the minimum temperature and the maximum temperature of the raw material 5 in the first region 25 are within the above range. More preferably.
[0097]
Further, the residence time (time required for passage) of the raw material 5 in the first region 25 is preferably 0.5 to 12 minutes, and more preferably 0.5 to 7 minutes. If the residence time in the first region 25 is less than the lower limit value, it may be difficult to sufficiently compatibilize the block polyester and the amorphous polyester. On the other hand, if the residence time in the first region 25 exceeds the upper limit value, the production efficiency is lowered, and depending on the temperature in the process unit 2, the number of rotations of the screw 22, the screw 23, etc., the raw material due to heat 5 may easily occur, and it may be difficult to sufficiently control the physical properties of the finally obtained toner.
[0098]
Moreover, it is preferable that the length of the 1st area | region 25 is 10-200 cm, and it is more preferable that it is 20-150 cm. If the length of the first region 25 is less than the lower limit value, it may be difficult to make the block polyester and the amorphous polyester sufficiently compatible. On the other hand, when the length of the first region 25 exceeds the upper limit value, the production efficiency is lowered, and depending on the temperature in the process unit 2, the rotational speed of the screw 22, the screw 23, etc., the raw material 5 due to heat is reduced. This tends to cause modification, and it may be difficult to sufficiently control the physical properties of the finally obtained toner.
[0099]
By the way, in the 1st area | region 25, block polyester and amorphous polyester are fully compatibilized by knead | mixing at comparatively high temperature. However, since the block polyester and the amorphous polyester are resins having molecular structures that are greatly different from each other, even if the block polyester and the amorphous polyester are sufficiently compatible, the kneaded product is cooled. Depending on conditions, block polyester and amorphous polyester may cause phase separation.
[0100]
Therefore, in the present embodiment, the second region 26 is provided and kneaded at a relatively lower temperature than the first region 25 as in the configuration shown in the drawing. Thereby, the dispersion | distribution failure of each component of the kneaded material 7 and generation | occurrence | production of phase separation can be prevented effectively. Further, when the raw material 5 contains a wax (especially a wax having low compatibility with the resin), the coarsening of the wax in the kneaded product 7 can be prevented, and the wax is finely adjusted to an appropriate particle size. Can be dispersed. As a result, the obtained kneaded product 7 can effectively suppress a decrease in grindability, and the finally obtained toner can suppress a decrease in transparency and durability and occurrence of offset. can do. Further, with respect to the toner, since the respective constituent components in the kneaded product 7 are uniformly dispersed, there is little variation in the characteristics among the toner particles, and the overall characteristics can be improved. . Therefore, the effect of each constituent component can be sufficiently exhibited.
In particular, by providing the first region 25 and the second region 26 as described above, the crystallization of the block polyester is efficiently advanced while sufficiently preventing phase separation in the second region 26. Therefore, the finally obtained toner is resistant to mechanical stress.
[0101]
Raw material temperature in the second region 26 (internal temperature of the second region 26) T₂[° C] is the softening point of the amorphous polyester T_1/2(A) When [° C.], (T_1/2(A) -20) ≦ T₂≤ (T_1/2It is preferable to satisfy the relationship (A) +20), and (T_1/2(A) -10) ≦ T₂≤ (T_1/2It is more preferable to satisfy the relationship (A) +10). Raw material temperature T in the second region 26₂By setting the value in such a range, crystals having an appropriate size can be precipitated in the finally obtained toner. In contrast, the raw material temperature T₂However, if it is less than the lower limit value, it may be difficult to sufficiently finely disperse each component of the kneaded product 7, and the fluidity of the block polyester and the amorphous polyester is lowered, resulting in toner productivity. May decrease. In addition, the raw material temperature T₂However, if the upper limit is exceeded, the above-mentioned effects due to the provision of the second region 26 may not be sufficiently obtained, and it becomes difficult to precipitate crystals of an appropriate size.
[0102]
Raw material temperature T in the second region 26₂The specific value varies depending on the resin composition, but is preferably 80 to 150 ° C, more preferably 90 to 140 ° C.
Further, in the second region 26, the raw material temperature T₂May be uniform or different depending on the site. In the latter case, the minimum temperature of the raw material 5 in the first region 25 is preferably within the above range.
In the configuration shown in the figure, the raw material temperature is T between the first region 25 and the second region 26.₁To T₂A temperature transition region 28 for shifting to is provided.
[0103]
Further, the residence time of the raw material 5 in the second region 26 is preferably 0.5 to 12 minutes, and more preferably 1 to 7 minutes. If the residence time in the second region 26 is less than the lower limit value, the above-described effect by providing the second region 26 may not be sufficiently obtained. On the other hand, if the residence time in the second region 26 exceeds the upper limit value, the production efficiency is lowered, and depending on the temperature in the process unit 2, the rotational speed of the screw 22, the screw 23, etc., the raw material due to heat 5 may easily occur, and it may be difficult to sufficiently control the physical properties of the finally obtained toner.
[0104]
In addition, the length of the second region 26 is preferably 20 to 200 cm, and more preferably 40 to 160 cm. If the length of the second region 26 is less than the lower limit value, the above-described effect by providing the second region 26 may not be sufficiently obtained. On the other hand, when the length of the second region 26 exceeds the upper limit value, the production efficiency is lowered. Depending on the temperature in the process unit 2, the number of rotations of the screw 22, the screw 23, and the like, the raw material 5 due to heat is reduced. This tends to cause modification, and it may be difficult to sufficiently control the physical properties of the finally obtained toner.
[0105]
In addition, the raw material temperature T in the first region 25₁And the raw material temperature T in the second region 26₂And (T₁-T₂) ≧ 80 [° C.] is preferably satisfied, and 80 ≦ (T₁-T₂) ≦ 160 is more preferable. By satisfying such a relationship, crystals having an appropriate size can be precipitated in the finally obtained toner. In contrast, (T₁-T₂) Is less than the lower limit, it may be difficult to sufficiently prevent phase separation in the cooling step described later.
[0106]
The number of rotations of the screw 22 and the screw 23 varies depending on the blending ratio of the block polyester and the amorphous polyester, their composition, molecular weight, and the like, but is preferably 50 to 600 rpm. If the number of rotations of the screw 22 and the screw 23 is less than the lower limit value, for example, in the first region 25, it may be difficult to sufficiently compatibilize the block polyester and the amorphous polyester. In the second region 26, it may be difficult to sufficiently prevent phase separation. On the other hand, when the rotation speeds of the screw 22 and the screw 23 exceed the upper limit value, the molecules of the polyester may be cut by shearing, and the resin characteristics may be deteriorated. In the illustrated configuration, a third region 27 different from the first region 25 and the second region 26 is provided on the feeder 4 side of the first region 25 (the side opposite to the second region 26). It has been. As described above, the process unit 2 may have a region other than the first region 25 and the second region 26.
[0107]
Raw material temperature T in the third region 27₃[° C.] is the raw material temperature T in the second region 26.₂Between (T₂−40) ≦ T₃≤ (T₂+40) is preferably satisfied, and (T₂−20) ≦ T₃≤ (T₂It is more preferable to satisfy the relationship +20). Raw material temperature T₃However, if it is less than the lower limit, the resin is hardly melted and the kneading torque may be too high. On the other hand, raw material temperature T₃However, when the upper limit is exceeded, the temperature of the raw material charging port becomes high, the feeder 4 is also heated, and the resin may melt and adhere to the feeder 4 in some cases.
[0108]
In the configuration shown in the figure, the material temperature is T between the third region 27 and the first region 25.₃To T₁A temperature transition region 29 for shifting to is provided.
Further, in the illustrated configuration, the configuration in which the first region 25, the second region 26, and the third region 27 are provided has been described, but the configuration in which other regions are provided. May be. For example, such a region may be between the first region 25 and the second region 26, or may be closer to the head unit 3 than the second region 26.
[0109]
[Extrusion process]
The kneaded material 7 kneaded in the process unit 2 is pushed out of the kneader 1 through the head unit 3 by the rotation of the screw 22 and the screw 23.
The head unit 3 has an internal space 31 into which the kneaded product 7 is fed from the process unit 2 and an extrusion port 32 through which the kneaded product 7 is extruded.
[0110]
Temperature of the kneaded material 7 in the internal space 31 (at least in the vicinity of the extrusion port 32) T₄[° C] is T₂It is preferable that the temperature is higher by about 10 ° C. Temperature T of kneaded material 7₄However, at such a temperature, the kneaded material 7 does not solidify in the internal space 31 and is easily extruded from the extrusion port 32.
In the illustrated configuration, the internal space 31 has a cross-sectional area gradually decreasing portion 33 in which the cross-sectional area gradually decreases in the direction of the extrusion port 32.
[0111]
By having such a cross-sectional area gradually decreasing portion 33, the extrusion amount of the kneaded material 7 extruded from the extrusion port 32 is stabilized, and the cooling rate of the kneaded material 7 in the cooling step described later is stabilized. As a result, the toner produced using the toner has a small variation in characteristics among the toner particles, and has excellent overall characteristics.
[0112]
[Cooling process]
The softened kneaded product 7 extruded from the extrusion port 32 of the head unit 3 is cooled by the cooler 6 and solidified.
The cooler 6 includes rolls 61, 62, 63, 64 and belts 65, 66.
[0113]
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.
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 kneaded material 7 extruded from the extrusion port 32 of the kneader 1 is introduced between the belt 65 and the belt 66. The kneaded material 7 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 kneaded material 7 is discharged from the discharge part 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.
[0114]
By the way, in the kneading step, since the shearing force is applied to the raw material 5, phase separation or the like is sufficiently prevented. Otherwise, phase separation may occur again. Therefore, it is preferable to cool the kneaded product 7 obtained as described above as soon as possible. Specifically, the cooling rate of the kneaded product 7 (for example, the cooling rate when the kneaded product 7 is cooled to about 60 ° C.) is preferably −3 ° C./second or more, and −5 to −100 ° C. More preferred is / sec. In addition, the time required from the end of the kneading step (when the shearing force is no longer applied) to the completion of the cooling step (for example, the time required for cooling the temperature of the kneaded product 7 to 60 ° C. or less) is 20 seconds. Or less, more preferably 3 to 12 seconds.
[0115]
In the above-described embodiment, the configuration using a continuous twin-screw kneading extruder as the kneader has been described, but the kneader used for kneading the raw materials is not limited to this. For the kneading of 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.
In the illustrated configuration, a kneader having two screws has been described. However, the number of screws may be one or three or more.
[0116]
Further, in the present embodiment, the configuration using one kneader has been described, but kneading may be performed using two kneaders. In this case, the process section of one kneader may be used as the first area 25 and the process section of the other kneader may be used as the second area 26. 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. The cooling of the kneaded product 7 extruded from the extrusion port 32 of the kneading machine 1 is not limited to that using the above-described cooling machine, and may be performed by air cooling or the like, for example.
[0117]
[Granulation process]
By granulating the kneaded material 7 that has undergone the cooling process 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.
[0118]
<Crushing process>
First, the kneaded material 7 that has undergone the cooling process as described above is 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 jet mill, and a pin mill.
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.
[0119]
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 fusion of the toners due to heat can be sufficiently prevented and suppressed. In addition, the external addition process as such pretreatment can be performed in the same manner as the external addition process as a post-process of the thermal spheronization process as described later, and an external additive described in detail later is used. Can be used.
[0120]
<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.
[0121]
In particular, when the polyester-based resin includes a block polyester having a crystalline block, the amorphous polyester is sufficiently softened while ensuring the stability of the shape of the powder for toner production to some extent during the thermal spheronization treatment. be able to. Therefore, compared with the case where a raw material not containing block polyester is used, the thermal spheronization treatment can be performed efficiently, and the circularity of the finally obtained toner (toner particles) is relatively high. Can be. Moreover, as a result, the effect by the thermal spheroidization process mentioned above can be exhibited more effectively.
[0122]
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.
[0123]
When the polyester-based resin contains a block polyester having a crystalline block, 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.
Moreover, you may perform such a thermal spheronization process in a liquid.
Further, after such a thermal spheronization step, a treatment such as a classification treatment may be performed as necessary.
For the classification treatment, for example, a sieve, an airflow classifier or the like can be used.
[0124]
[External addition process (external addition process)]
Next, an external additive is applied to the heat-spheroidized toner production powder.
Thereby, the toner of the present invention is obtained. The toner thus obtained has the property of being easily negatively charged (negatively chargeable toner).
By the way, this invention has the characteristics also in the point which combined the external additive most suitable for the said resin.
In particular, the present invention is characterized in that positively chargeable silica is used as an external additive.
[0125]
Ordinary silica (negatively chargeable silica) is usually easily charged negatively, whereas positively charged silica used in the present invention has a property of being easily charged positively. By utilizing such properties, the positively chargeable silica can function as a microcarrier that is charged to a polarity opposite to that of the toner particles. When such a positively-charged silica that functions as a microcarrier is contained in the toner, the toner particles that are reversely charged at the time of development or the like (the toner particles are charged to a polarity opposite to the polarity that should originally be shown when charging, that is, , Generation of positively charged toner particles) can be effectively prevented and suppressed. As a result, the toner is less likely to cause inconveniences such as so-called fog. Such a function as a microcarrier appears more prominently when a predetermined proportion of positively-charged silica contained in the toner is released from the toner base particles.
[0126]
Further, the toner added with positively chargeable silica as an external additive exhibits particularly excellent stability against mechanical stress. Furthermore, the positively chargeable silica is low in fluidity, and the toner added with the positively chargeable silica as an external additive has particularly a triboelectric chargeability as a toner compared to the case where other external additives are added. It will be excellent.
[0127]
As will be described later, the toner of the present invention has an acid value of 8 KOHmg / g or less. By the way, such a low acid value toner is inherently small in charge amount and difficult to control charging. However, in the present invention, by using positively chargeable silica, the charging characteristics of the entire toner can be made excellent.
[0128]
Furthermore, in the present invention, when such positively chargeable silica is used in combination with the polyester resin as described above, the following synergistic effect is obtained.
That is, as described above, when a polyester resin containing a block polyester having a crystalline block with high crystallinity is used, crystals of a predetermined size formed mainly by the crystalline block in the toner particles. It can have. By having such crystals, the positively chargeable silica is difficult to be embedded in the toner base particles. Thereby, in the toner particles, the positively chargeable silica can sufficiently exhibit the function as the microcarrier as described above. Accordingly, the charging characteristics of the toner as a whole can be made particularly excellent. Further, since the positively chargeable silica is difficult to be embedded in the toner base particles, the function of the external additive can be sufficiently exhibited even when the content of the external additive is relatively small. For this reason, 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.
[0129]
In addition, as described above, when the block polyester is included, crystals of an appropriate size with high hardness can be precipitated in the toner. As a result, the ratio of positively charged silica adhering to the toner base particles (or the ratio of free positively charged silica) can be maintained within a preferable range over a long period of time. As a result, the functions of the positively chargeable silica, particularly the functions as microcarriers, can be sufficiently exhibited over a long period of time. Therefore, the toner finally obtained is excellent in durability and has particularly excellent charging characteristics.
[0130]
The average particle diameter of the primary particles of the positively chargeable silica is not particularly limited, but is preferably 30 to 200 μm, and more preferably 30 to 50 μm. When the average particle diameter of the primary particles of the positively chargeable silica is within such a range, the triboelectric chargeability is particularly improved, and the above-described effect becomes more remarkable. In addition, when the particle size of the primary particles of the positively chargeable silica is relatively large, the surface of the toner particles is not completely covered, and even when used in a fixing machine as described later, the fixability is lowered. As compared with the case where other external additives are added, particularly excellent stability against mechanical stress is exhibited. In particular, when a polyester-based resin containing a block polyester having a crystalline block with high crystallinity is used, the above-described effect becomes more remarkable. In the present specification, “average particle diameter” refers to an average particle diameter based on volume.
[0131]
Further, the content of the positively chargeable silica in the toner is not particularly limited, but is preferably 0.1 to 2.0 wt%, and more preferably 0.2 to 1.0 wt%. When the content of the positively chargeable silica is within such a range, the effect of including the positively chargeable silica described above becomes more remarkable. On the other hand, if the content of positively chargeable silica is less than the lower limit, the effects of the present invention may not be sufficiently exhibited. Further, when the content of the positively chargeable silica exceeds the above upper limit value, the charge amount of the toner as a whole tends to decrease.
[0132]
Ratio of positively-charged silica contained in the toner that is free from the surface of the toner particles (mother particles) (free rate: free from the mother particles relative to the total amount of positively-charged silica contained in the toner) The ratio of positively-charged silica) is preferably 0.4 to 10 wt%, more preferably 0.5 to 5.0 wt%. When the positively chargeable silica is liberated in such a range, the effect of the positively chargeable silica described above, particularly the effect as a microcarrier, is more remarkably exhibited.
[0133]
The amount of silica released from the toner particles is, for example, the annual meeting of the Electrophotographic Society (95 times in total) “Japan Hardcopy '97”, “New External Evaluation Method-Toner Analysis with Particle Analyzer” (Toshiyuki Suzuki, It can be measured by applying the method disclosed in Toshio Takahara, sponsored by the Electrophotographic Society, July 9-11, 1997).
This measurement method uses silica (SiO 2) on the surface of the mother particles made of resin (C).₂) Is formed by introducing toner particles into the plasma to excite the toner particles, obtaining an emission spectrum associated with the excitation, and performing elemental analysis.
[0134]
First, silica (SiO2) is used as a 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 silica (SiO₂) Both emit light. At this time, the mother particles (C) and silica (SiO₂) Are simultaneously introduced into the plasma, so that the mother particles (C) and silica (SiO₂) Will emit light at the same time. Thus, the mother particles (C) and silica (SiO₂) Simultaneously emit light, the mother particles (C) and silica (SiO₂) And are synchronized. In other words, the mother particles (C) and silica (SiO₂Is synchronized with silica (SiO 2).₂) Represents the state of adhering to the mother particles (C).
[0135]
Silica (SiO₂) Not adhering to the mother particles (C) or silica released from the mother particles (C) (SiO₂) Is introduced into the plasma, the mother particles (C) and silica (SiO₂) Emit light, but at this time, the mother particles (C) and silica (SiO₂) Are introduced into the plasma at different times, so that the mother particles (C) and silica (SiO₂(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).
[0136]
Thus, the mother particles (C) and silica (SiO₂) Emit light at different times, the mother particles (C) and silica (SiO₂) Is not synchronized (that is, asynchronous). In other words, the mother particles (C) and silica (SiO₂) Is asynchronous with silica (SiO 2).₂) Represents a state of not adhering to the mother particle (C).
[0137]
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, SiO₂) Is proportional to the number of atoms. Therefore, in order to express the luminescence intensity of the element as the size of the particle, the mother particle (C) and silica (SiO₂) Emission of these base particles (C) and silica (SiO₂) 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. And silica (SiO₂) Is so small that these particles cannot be detected one by one. Therefore, the detected emission signals of the external additives are added together and converted into one equivalent particle for analysis.
[0138]
When the equivalent particle diameters of the equivalent particles obtained from the emission spectra of the mother particles and the external additives are plotted for each toner particle, an equivalent particle size 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 silica (SiO 2).₂). And the equivalent particles on the horizontal axis are silica (SiO₂) Represents an asynchronous mother particle (C) not attached, and the equivalent particle on the vertical axis represents the asynchronous silica (SiO 2) released from the mother particle (C).₂). Equivalent particles that are not on the horizontal and vertical axes are silica (SiO₂) Represents the synchronous toner attached. In this way, silica (SiO2) with respect to the toner base particles (C) is obtained.₂) Is analyzed to determine the liberation rate of silica.
[0139]
The positively chargeable silica may be produced by any method. For example, the positively chargeable silica is obtained by subjecting negatively charged silica to a surface treatment with a silane coupling agent having a functional group such as an amino group. be able to.
The external additive used in this step may be substantially composed only of the positively-charged silica described above, or may contain other components and materials.
[0140]
Examples of materials other than positively-charged silica contained in the external additive include titanium oxide, negatively-charged silica, aluminum oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, zinc oxide, alumina, and magnetite. Fine particles composed of inorganic materials such as metal 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 , Polyester resins, aliphatic metal salts (for example, magnesium stearate) and other organic materials, and the like can be used, and one or more selected from these can be used in combination.
Examples of titanium oxide that can be used as an external additive include rutile type titanium oxide, anatase type titanium oxide, and rutile anatase type titanium oxide.
[0141]
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.
[0142]
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.
[0143]
In particular, rutile-anatase type titanium oxide may be used in combination with positively-charged silica as described above to make the toner obtained have a large charge amount (absolute value) and a sharper charge distribution. it can.
In particular, when rutile-anatase type titanium oxide is used in combination with a polyester resin as described above, the following synergistic effects are exhibited.
[0144]
That is, as described above, when a polyester resin containing a block polyester having a crystalline block with high crystallinity is used, crystals of a predetermined size formed mainly by the crystalline block in the toner particles. It can have. 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, when used in combination with the polyester-based resin described above, the function of the rutile-anatase type titanium oxide can be sufficiently exerted, so that the amount of the external additive 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.
[0145]
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.
[0146]
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).
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.
[0147]
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.
[0148]
The content of the rutile-anatase type titanium oxide in the toner is not particularly limited, but is preferably 0.1 to 20 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.
[0149]
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.
[0150]
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).
[0151]
In addition, when negatively chargeable silica is used as an 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.
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[Μm], the average particle diameter of the negatively charged silica is D₂When it is [μm], 0.2 ≦ D₁/ D₂It is preferable to satisfy the relationship of ≦ 15, 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.
[0152]
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.
Such an external additive can be added, for example, by mixing with a powder for toner production using a Henschel mixer or the like.
In addition, the external addition process may be performed in one step, or may be performed in two or more steps. For example, first, an external additive other than positively-charged silica such as rutile-anatase-type titanium oxide or negatively-charged silica described above may be applied to the toner base particles, and then positively-charged silica may be added. .
[0153]
The content of the external additive in the toner is not particularly limited, but is preferably 1.0 to 4.0 wt%, and more preferably 1.5 to 3.0 wt%. If the content of the external additive is less than the lower limit, the effect of the external additive described above may not be sufficiently exhibited. On the other hand, when the content of the external additive exceeds the upper limit, the ratio of the free external additive tends to increase, and the effects of the present invention may not be sufficiently obtained.
[0154]
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.
[0155]
Percentage of external additives contained in the toner that are free from the surface of the toner particles (mother particles) (free rate: the amount of external additives free from the mother particles relative to the total amount of external additives contained in the toner) The proportion of the additive) is preferably 0.2 to 5.0 wt%, more preferably 0.2 to 3.0 wt%, and even more preferably 0.5 to 2.0 wt%. . When the external additive is free in such a range, the free external additive (free external additive) functions as a microcarrier, and the charging characteristics of the toner as a whole are particularly excellent.
Further, the ratio of the mother particles (free mother particles) to which no external additive is attached to the toner mother particles is preferably 30 wt% or less, and more preferably 1 to 15 wt%. By satisfying such a condition, the above-described effects become more remarkable, and toner particles can be more effectively prevented from being overcharged.
[0156]
Note that the ratio of the free external additive and the ratio of the free mother particles can be determined by applying the method for measuring the amount of positively charged silica released from the toner particles as described above (see FIG. 4). .
The ratio of the external additive (positively-charged silica) released from the toner base particles and the ratio of the base particles (free base particles) to which no external additive is attached are, for example, the external additive and the powder for toner production. And by adjusting the mixing conditions (mixing time, Henschel mixer screw rotation speed, etc.).
[0157]
The toner (toner powder) obtained as described above preferably has an average circularity R represented by the following formula (I) of 0.91 to 0.98, preferably 0.93 to 0.98. Is more preferable. 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 be reduced. 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. )
[0158]
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.
The ratio between the average particle diameter of the toner and the average particle diameter of the positively chargeable silica is preferably 30: 1 to 600: 1, and more preferably 100: 1 to 500: 1.
[0159]
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.
[0160]
In addition, the composition of the block polyester contained in the toner (constituent monomer, abundance ratio of the crystalline block, etc.), the average weight molecular weight Mw, the glass transition point, the softening point, the melting point, etc. The average weight molecular weight Mw, glass transition point, softening point, and the like are preferably the same as those described in the item of the constituent material of the raw material 5, but may be changed during the manufacturing process.
[0161]
Further, when the toner contains wax, the content is not particularly limited, but is preferably 5.0 wt% or less, more preferably 3.0 wt% or less, and 0.5-3. More preferably, it is 0 wt%. 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.
[0162]
The present invention is characterized in that the above-described polyester-based resin and positively-charged silica are combined. However, the present invention is not limited thereto, and further has a characteristic in that the acid value of the toner is defined. 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 such toner is also affected by the acid value of the resin itself constituting the toner, but in addition to the acid value of the resin, for example, a colorant, wax, external additive, etc. used as a constituent material of the toner These factors are comprehensively determined in consideration of factors such as the acid value of the toner and the toner production conditions (for example, the kneading temperature in the kneading step, the rotational speed of the screw and the cooling rate of the kneaded product in the cooling step). Thus, the acid value of the toner is not determined solely by the acid value of the resin.
[0163]
The present invention is characterized in that the acid value of the toner is 8.0 KOH mg / g or less. Thus, by setting the acid value of the toner to 8.0 KOHmg / g or less, the environmental characteristics (particularly moisture resistance) of the toner are excellent. In addition, when the acid value of the toner is low, the charge amount of the toner is reduced, so that when the toner is used as a non-contact developing toner, the toner flying property is improved. Thus, the toner of the present invention can be suitably used as a non-contact developing toner.
[0164]
By the way, generally, when the acid value is lowered in this way, there is a problem that the charge amount of the toner is lowered and the charge control becomes difficult. However, as described above, the toner of the present invention contains positively chargeable silica having a relatively large particle size. By including such positively chargeable silica, the positively chargeable silica functions as the above-mentioned microcarrier, and toner particles having a reverse chargeability are generated at the time of development or the like while having a low charge amount. Can be effectively prevented and suppressed. Thereby, a toner having a sharp charge distribution can be obtained. Furthermore, the inclusion of positively-charged silica having a relatively large particle size facilitates charging (friction charging) due to friction between the toner particles (mother particles) and the external additive. It will be excellent. In particular, when the toner particles include the above-described block polyester and amorphous polyester, the above-described effect becomes more remarkable. That is, by including a hard component such as a crystalline block, friction between toner particles and electrification (friction charging) due to friction between toner particles (mother particles) and an external additive easily occur. . Therefore, even if the acid value is low, the chargeability of the toner becomes excellent, and the charge amount of the toner can be controlled to an appropriate value. In addition, since the acid value is low, the toner has excellent environmental characteristics (particularly moisture resistance). That is, the toner of the present invention has both charging characteristics and environmental characteristics.
On the other hand, when the acid value of the toner exceeds 8.0 KOHmg / g, the chemical stability of the toner is lowered, and the environmental characteristics (particularly moisture resistance) are lowered. On the other hand, when the acid value of the toner exceeds 8.0 KOHmg / g, the chargeability of the toner becomes unstable, and the variation in the charge amount between the toner particles increases.
[0165]
As described above, in the present invention, the acid value of the toner is 8.0 KOHmg / g or less. In particular, the acid value of the toner is preferably 0.01 to 3.0 KOHmg / g. More preferably, it is 0.01-1.0 KOHmg / g. When the acid value of the toner is within the above range, the above-described effects become more prominent, in particular, stable chargeability is obtained, and the environmental characteristics (particularly, moisture resistance) of the toner are further improved.
[0166]
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.
[0167]
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. And the production conditions of the toner (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 processing temperature in the thermal spheronization step, etc.).
[0168]
Further, when the polyester resin as described above is used, there are crystals mainly composed of crystalline blocks of block polyester.
Such crystals preferably have an average length (average length in the longitudinal direction) of 10 to 1000 nm, and more preferably 50 to 700 nm. When the length of the crystal is within such a range, the toner shape stability is particularly excellent, and particularly excellent stability against mechanical stress is exhibited. In particular, the external additive is more reliably held near the surface of the toner particles (the external additive can be effectively prevented from being buried in the mother particles). In particular, the stability is excellent, and filming and the like are less likely to occur. The size of the crystal is, for example, changing the molecular weight and randomness of the block polyester by controlling the production conditions of the block polyester used as a raw material component, or the blending ratio of the block polyester and the amorphous polyester. It can be appropriately adjusted by changing or changing the conditions of the kneading step and the cooling step described above.
[0169]
Further, when the toner contains rutile-anatase type titanium oxide, it is preferable that the following relationship is satisfied. 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.
[0170]
Further, when the polyester-based resin as described above is used, it is preferable that the block polyester and the amorphous polyester are compatible with each other as much as possible. As a result, variations in characteristics among the toner particles are small, the characteristics of the toner as a whole are more stable, and the effects of the present invention become more remarkable.
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.
[0171]
The fixing device using the toner of the present invention is not particularly limited, but is preferably a contact-type fixing device as will be described later. As a result, the advantages of improving the chargeability by including the positively-charged silica having a relatively large particle diameter and the excellent environmental characteristics due to the low acid value of the toner are fully exhibited, and a wide range of good fixing. Is secured. In particular, when the toner contains a block polyester and an amorphous polyester, due to the high releasability from the fixing roller by the crystal of the block polyester and the fixability (fixing strength) improving effect by the low viscosity amorphous polyester, The aforementioned effects can be made more remarkable.
[0172]
Next, the fixing device and the image forming apparatus of the present invention will be described.
5 is an overall configuration diagram showing a preferred embodiment of the image forming apparatus of the present invention, FIG. 6 is a cross-sectional view of a developing device included in the image forming apparatus of FIG. 5, and FIG. FIG. 8 is a perspective view illustrating a detailed structure of the fixing device of the present invention, a partially broken cross-section, FIG. 8 is a cross-sectional view of a main part of the fixing device in FIG. 7, and FIG. FIG. 10 is a side view showing a mounting state of the peeling member constituting the fixing device of FIG. 7, FIG. 11 is a front view of the fixing device of FIG. 7 as viewed from above, and FIG. FIG. 13 is a diagram schematically illustrating the shape of the fixing roller and the pressure roller and the shape of the nip portion, and FIG. 14 is a diagram illustrating FIG. 13. FIG. 15A is a cross-sectional view taken along line XX of FIG. Shows the shape schematically, FIG. 16 is a sectional view taken along line Y-Y of FIG. 15 (a), FIG. 17, a fixing roller, a cross-sectional view for explaining a gap between the peeling member.
[0173]
An image carrier 30 including a photosensitive drum is disposed in the apparatus main body 20 of the image forming apparatus 10 and is rotationally driven 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.
[0174]
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 driven to rotate by a motor (not shown). It is the composition which becomes. 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.
[0175]
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 that functions as a “toner carrier” is abutted against the image carrier (photosensitive member) 30 (contact type) or is opposed to each other with a predetermined gap (non-contact type). 603 and 604 are configured to be engaged with a rotation driving unit (not shown) provided on the main body side and rotate in a predetermined direction. As described above, the developing device includes a contact type and a non-contact type. When the non-contact type is used, there is an effect that the durability of the toner is excellent. 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.
[0176]
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.
[0177]
The intermediate transfer device 70 includes a driving roller 90 and a driven roller 100, an intermediate transfer belt 110 that is driven by the two rollers in the direction indicated by the arrow, and a primary transfer that is disposed on the back surface of the belt 110 so as to face the image carrier 30. A roller 120, a transfer belt cleaner 130 for removing residual toner on the belt 110, and a drive roller 90 are arranged to face the four-color full-color image formed on the intermediate transfer belt 110 on a recording medium (paper or the like). And a secondary transfer roller 140 for transferring the toner to the ink.
[0178]
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 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 6 and the intermediate transfer belt 110 are driven to rotate. First, the outer peripheral surface of the image carrier 30 is moved 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.
[0179]
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.
[0180]
At the position of the latent image 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.
[0181]
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.
[0182]
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. The shafts of the fixing roller 210 and the pressure roller 220 are connected from a horizontal line. It arrange | positions so that it may have the angle of (theta). Note that 0 ° ≦ θ ≦ 30 °.
[0183]
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 the driving gear 28 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.
[0184]
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.
[0185]
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 340 in which the pressure roller 220 side is recessed in a concave shape.
[0186]
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.
[0187]
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.
[0188]
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 33, 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.
[0189]
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.
[0190]
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 tip of the peeling member 310 on the fixing roller 210 side is disposed so as to incline toward the exit of the nip portion 340, and is not in contact with and close to the fixing roller 210. 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.
[0191]
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 33, whereby 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.
[0192]
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 in contact with each other. 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.
[0193]
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.
[0194]
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.
[0195]
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 the arrangement angle θ of the peeling member 310 with respect to the tangent S of the outlet 341 of the fixing nip 340._AIs preferably set in the range of −5 to 25 °. Arrangement angle θ of peeling member 310 with respect to tangent S of 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 “−”.
[0196]
Further, the fixing roller 210 and the pressure roller 220 have, for example, substantially constant outer diameters in the respective axial directions (they may have a substantially cylindrical shape, but the outer diameters are small in the vicinity of 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.
[0197]
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.
[0198]
In this way, when the peeling member 310 disposed along the fixing roller 210 has a shape that follows the shape of the outlet 341 of the nip portion 340, the peeling member 310 on the fixing roller 210 side is peeled off at the time of peeling. Effectively eliminates adverse effects caused by increased contact between the side edge 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. It can be prevented and suppressed.
[0199]
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.
[0200]
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 10 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.
[0201]
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.
[0202]
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.
[0203]
Further, the temperature of the fixing nip portion 340 during operation is preferably 100 to 200 ° 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.
In addition, the set temperature on the surface of the fixing roller 210 during operation (the set temperature on the surface of the fixing roller 210) is preferably 110 to 220 ° C, and more preferably 130 to 200 ° C. If the set temperature of the fixing roller 210 is within such a range, both the fixing strength of the toner can be secured and the temperature rise time (warm-up time) can be shortened.
[0204]
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, when the fixed toner is in a molten state (low viscosity state) and comes into contact with the release member, it may be difficult to reliably release the recording medium.
[0205]
On the other hand, since the toner of the present invention contains positively-charged silica having a relatively large particle diameter, it is possible to sufficiently prevent deterioration of fixing ability, and further, compared with the case where other external additives are added. In particular, it exhibits excellent stability against mechanical stress. For this reason, the toner of the present invention can be suitably applied to the fixing device 190 described above. In particular, when the polyester resin contains a block polyester and an amorphous polyester, the following effects can be obtained. That is, since the toner of the present invention contains amorphous polyester having a relatively low softening point, the toner of the present invention can be reliably fixed to the recording medium when passing through the fixing nip portion 340. By including a block polyester having a crystalline block, a crystal having a high hardness and an appropriate size is likely to precipitate therein. 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.
[0206]
While the toner, the fixing device, and the image forming apparatus of the present invention have been described based on the preferred embodiments, the present invention is not limited to this.
For example, in the above description, an example in which a block polyester and an amorphous polyester are used in combination as a polyester resin has been described. However, 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, the toner of the present invention is obtained by subjecting the powder for toner production to an external additive treatment directly on the powder for toner production without performing the above-mentioned thermal spheronization treatment. Also good. In the above-described embodiment, the configuration using the pulverization method has been described as the toner production method. However, the toner of the present invention may be obtained by a spray drying method, a polymerization method, or the like.
[0207]
In the above-described embodiment, the toner manufacturing powder is described as being obtained by a pulverization method. However, the toner manufacturing powder may be manufactured by other methods such as a spray drying method or a polymerization method. Good.
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.
[0208]
In the embodiment described above, the configuration using a continuous twin screw extruder as the kneader has been described, but the kneader used for kneading the raw materials is not limited to this. For the kneading of 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.
[0209]
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.
[0210]
In addition, the fixing device and the image forming apparatus of the present invention are not limited to those described in the above-described embodiments, and each unit constituting the fixing device and the image forming apparatus has an arbitrary configuration that can exhibit the same function. 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.
[0211]
【Example】
[1] Production of polyester
Prior to the production of the toner, the following three types of polyesters A, A ', B, C, D, and E 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.
[0212]
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).
[0213]
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.
[0214]
[1.2] Production of polyester A '(amorphous polyester)
First, a mixture of neopentyl glycol: 40 mol parts, ethylene glycol: 30 mol parts, 1,4-cyclohexanediol: 30 mol parts, dimethyl terephthalate: 105 mol parts, and phthalic anhydride: 15 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, and a mixture of the diol component and the dicarboxylic acid component: 1000 g And an esterification condensation catalyst (titanium tetrabutoxide (PPB)): 1 g were put into 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).
[0215]
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 110 ° C., glass transition point T_gIs 62 ° C. and the weight average molecular weight Mw is 1.1 × 10⁴Met.
[0216]
[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 according to a conventional method. Polyester A obtained in [1.1] above: 70 Molten part and 1,4-butanediol as diol component: 15 mol part and dimethyl terephthalate as dicarboxylic acid component: 15 mol part mixed solution: 1000 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).
[0217]
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.
[0218]
[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 stirring device were installed according to a conventional method. Polyester A ′ obtained in [1.2] above: 90 mol parts, 1,4-butanediol as a diol component: 5 mol parts and dimethyl terephthalate as a dicarboxylic acid component: 5 mol parts: 1000 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 C (PES-C).
[0219]
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 10 mJ / mg. Also, the softening point T of polyester C_1/2Is 120 ° C., glass transition point T_gIs 64 ° C. and the weight average molecular weight Mw is 2.1 × 10⁴Met.
[0220]
[1.5] Production of polyester D (polyester having high crystallinity using aliphatic diol)
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).
[0221]
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.
[0222]
[1.6] Production of polyester E (polyester using aromatic diol)
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 a propylene oxide adduct of bisphenol A as a diol component: 50 moles A mixture of 1000 parts of terephthalic acid as a dicarboxylic acid component: 1000 g 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 while the generated water and methanol were allowed to flow out of the distillation tower at a material temperature of 230 ° C. When water stopped flowing 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 250 ° 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 E (PES-E).
[0223]
The melting point of polyester E in the measurement using a differential scanning calorimeter could not be confirmed. Also, the softening point T of polyester E_1/2Is 115 ° C., glass transition point T_gWas 62 ° C. and the weight average molecular weight Mw was 12,000.
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.
[0224]
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 the melting point T_mAs sought.
[0225]
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).
[0226]
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.
[0227]
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 is poured into a sample bottle dedicated to centrifugation, centrifuged at 2000 rpm for 5 minutes in a centrifuge, and the supernatant is filtered through a sample preparation 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.
[0228]
[2] Manufacture of toner
A toner was manufactured as follows.
Example 1
First, polyester A: 80 parts by weight as an amorphous polyester, polyester B: 20 parts by weight as a block polyester, quinacridone (PR 122): 6 parts by weight as a colorant, chromium salicylate complex (Bontron E as a charge control agent) -81): 1 part by weight, and 2 parts by weight of carnauba wax as a wax were prepared.
[0229]
These components were mixed using a 20 L type Henschel mixer to obtain a raw material for toner production.
Next, this raw material (mixture) was kneaded using a twin-screw kneading extruder (Toshiba Machine Co., Ltd., TEM-41 type) as shown in FIG.
The total length of the process part of the twin-screw kneading extruder was 160 cm, the length of the first region was 32 cm, the length of the second region was 80 cm, and the length of the third region was 16 cm.
[0230]
In addition, the temperature of the raw material in the process part was set to 240 ° C. in the first region, 100 ° C. in the second region, and 100 ° C. in the third region. The screw rotation speed was 120 rpm, and the raw material charging speed was 20 kg / hour.
The time required for the raw material to pass through the first region, determined from such conditions, is about 1.5 minutes, and the time required to pass through the second region is about 3 minutes.
[0231]
The raw material (kneaded material) kneaded in the process part was extruded to the outside of the biaxial kneading extruder through the head part. The temperature of the kneaded material in the head part was adjusted to 110 ° C.
Thus, the kneaded material extruded from the extrusion port of the twin-screw kneading extruder was cooled using a cooling machine as shown in FIG. The temperature of the kneaded material immediately after the cooling step was about 46 ° C.
[0232]
The cooling rate of the 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.
The kneaded product cooled as described above was coarsely pulverized (average particle size: 1 to 2 mm), and then finely pulverized. A hammer 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 at a pulverization air pressure: 500 [kPa] and a rotor rotational speed: 7000 [rpm].
[0233]
The pulverized material thus obtained was classified with an airflow diverter (manufactured by Hosokawa Micron Corporation, 100 ATP).
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 spheronizer (Nippon Pneumatic Co., Ltd., SFS3 type). The temperature of the atmosphere during the heat spheronization treatment was 270 ° C.
[0234]
Thereafter, an external additive was applied to the powder subjected to the thermal spheronization treatment to obtain a toner. Application of the external additive was performed by using a 20 L type Henschel mixer, 100 parts by weight of the powder subjected to the thermal spheronization treatment, and 2.5 parts by weight of the external additive, rotating at 1400 rpm, and mixing time: The mixing was performed under the condition of 4 minutes. As external additives, positively charged silica (average particle diameter: 40 nm): 0.5 part by weight, and rutile-anatase type titanium oxide (substantially spindle shape, average major axis diameter: 30 nm): 2 parts by weight are used. It was. As the positively chargeable silica, one obtained by subjecting negatively chargeable silica to surface treatment (hydrophobization treatment) using an amino group-containing silane coupling agent (aminosilane) was 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. A thing was used.
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.
[0235]
The average particle size of the finally obtained toner was 7.5 μm. The obtained toner had an average circularity R of 0.96. The acid value of the toner was 0.8 KOH mg / g. The average length of the crystals in the toner was 500 nm. Further, the coverage of the external additive in the obtained toner was 130%. Further, of the positively-charged silica contained in the toner, the ratio (free rate) of those present as free external additives is 1.6%, and among the rutile-anatase type titanium oxide contained in the toner, The ratio (free rate) of those present as free external additives was 2.5%.
[0236]
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).
[0237]
(Examples 2 to 5)
The content of polyester A and the content of polyester B in the raw material used for the kneading step are as shown in Table 1, and the positive charge used for 100 parts by weight of the powder subjected to thermal spheronization treatment in the external addition step A toner was produced in the same manner as in Example 1 except that the content of the functional silica was as shown in Table 1.
[0238]
(Example 6)
Instead of polyester B, polyester C is used, the content of polyester A in the raw material used in the kneading process is changed to 70 parts by weight, and the content of polyester C is changed to 30 parts by weight. Powder: 100 parts by weight, with respect to 100 parts by weight, as an external additive, positively chargeable silica (average particle size: 30 nm): 0.5 part by weight, negatively chargeable small particle size silica (average particle diameter: 12 nm): 1 Part by weight, negatively chargeable large particle size silica (average particle size: 40 nm): 0.5 part by weight, rutile anatase type titanium oxide (substantially spindle shape, average major axis diameter: 30 nm): 1 part by weight A toner was manufactured in the same manner as in Example 1 except that the external addition treatment was performed. 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.
[0239]
(Example 7)
In the external addition step, the above-mentioned implementation was performed except that the powder subjected to the thermal spheronization treatment: 100 parts by weight was used as the external additive, positively charged silica (average particle size: 100 nm): 0.5 parts by weight. A toner was produced in the same manner as in Example 6.
(Example 8)
Instead of polyester A, polyester A ′ is used, and the content of polyester A ′ in the raw material used in the kneading process is changed to 30 parts by weight, and the content of polyester B is changed to 70 parts by weight. Powder: 100 parts by weight, with respect to 100 parts by weight, as an external additive, positively chargeable silica (average particle diameter: 200 nm): 0.5 part by weight, and negatively chargeable small particle diameter silica (average particle diameter: 12 nm) 1 part by weight, negatively chargeable large particle size silica (average particle size: 40 nm): 0.5 part by weight, rutile anatase type titanium oxide (substantially spindle shape, average major axis diameter: 30 nm): 1 part by weight A toner was produced in the same manner as in Example 1 except that the external addition treatment was performed using 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.
[0240]
(Examples 9 and 10)
The content of polyester A, the content of polyester B and the content of carnauba wax in the raw material used for the kneading process are shown in Table 1, and the average particle diameter and content of positively-charged silica as an external additive are shown. A toner was manufactured in the same manner as in Example 6 except that it was changed as shown in 1.
(Example 11)
Using oxidized polyethylene wax instead of carnauba wax, the content of polyester A in the raw material used in the kneading step is 80 parts by weight, the content of polyester B is 20 parts by weight, and the content of oxidized polyethylene wax is 3 parts by weight. A toner was manufactured in the same manner as in Example 9 except that.
[0241]
Example 12
A toner was produced in the same manner as in Example 1 except that 100 parts by weight of polyester D was used instead of 80 parts by weight of polyester A and 20 parts by weight of polyester B.
(Example 13)
A toner was prepared in the same manner as in Example 1 except that polyester D was used instead of polyester B, and the content of polyester A in the raw material to be subjected to the kneading process was 50 parts by weight and the content of polyester D was 50 parts by weight. Manufactured.
[0242]
(Example 14)
Polyester A: 80 parts by weight, Polyester B: 20 parts by weight Polyester A: 100 parts by weight, and external addition process with respect to 100 parts by weight of powder subjected to thermal spheronization in the external addition step As an agent, positively charged silica (average particle size: 40 nm): 0.5 part by weight, negatively charged small particle size silica (average particle size: 12 nm): 1 part by weight, negatively charged large particle size silica ( Average particle diameter: 40 nm): 0.5 parts by weight and rutile-anatase type titanium oxide (substantially spindle shape, average major axis diameter: 30 nm), except that the external addition treatment was performed using 1 part by weight. A toner was produced in the same manner as in Example 1. 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.
(Example 15)
A toner was produced in the same manner as in Example 14 except that polyester A: 90 parts by weight and polyester A ': 10 parts by weight were used instead of polyester A: 100 parts by weight.
[0243]
(Example 16)
A toner was produced in the same manner as in Example 14 except that polyester A: 75 parts by weight and polyester A ': 25 parts by weight were used instead of polyester A: 100 parts by weight.
(Example 17)
A toner was produced in the same manner as in Example 14 except that 50 parts by weight of polyester A, 20 parts by weight of polyester B, and 30 parts by weight of polyester A ′ were used instead of 100 parts by weight of polyester A.
[0244]
(Comparative Example 1)
Instead of polyester B, polyester D is used, the content of polyester A in the raw material used for the kneading process is changed to 80 parts by weight, and the content of polyester D is changed to 20 parts by weight, and positively chargeable silica is used as an external additive. A toner was produced in the same manner as in Example 1 except that there was no toner.
(Comparative Example 2)
Aside from using polyester A ′ in place of polyester A and polyester C in place of polyester B, using 50 parts by weight of polyester A ′ and 50 parts by weight of polyester C in the raw material used in the kneading step. In the same manner as in Example 1, a toner was produced.
[0245]
(Comparative Example 3)
Using polyester A ′ instead of polyester A, the content of polyester A ′ in the raw material used for the kneading step was 30 parts by weight, the content of polyester B was 70 parts by weight, and the content of carnauba wax was 5 parts by weight. A toner was manufactured in the same manner as in Example 1 except for the above.
(Comparative Example 4)
Using oxidized polyethylene wax instead of carnauba wax, the content of polyester A ′ in the raw material used for the kneading step is 30 parts by weight, the content of polyester B is 70 parts by weight, and the content of oxidized polyethylene wax is 3 parts by weight. A toner was manufactured in the same manner as in Comparative Example 3 except that.
[0246]
(Comparative Example 5)
A toner was manufactured in the same manner as in Example 1 except that 100 parts by weight of polyester E was used instead of 80 parts by weight of polyester A and 20 parts by weight of polyester B.
(Comparative Example 6)
A toner was produced in the same manner as in Example 16 except that polyester A: 75 parts by weight and polyester A ′: 25 parts by weight were used instead of polyester A: 30 parts by weight and polyester A ′: 70 parts by weight. .
[0247]
Constituent components of the toners of the respective Examples and Comparative Examples are shown in Tables 1 and 2, and the average particle diameter, average circularity R, acid value, average length of crystals in the toner, and external additives Tables 3 and 4 collectively show the coverage, the release rate of positively charged silica, and the release rate of rutile-anatase type titanium oxide. In the table, polyester A, polyester A ′, polyester B, polyester C, polyester D, and polyester E are PES-A, PES-A ′, PES-B, PES-C, PES-D, and PES-, respectively. The charge control agent is represented by CCA, the carnauba wax as wax, and the oxidized polyethylene are represented by KW and PE, respectively.
[0248]
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, heated and melted, and adjusted to 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 shown in Tables 3 and 4 together.
[0249]
[Table 1]

[0250]
[Table 2]

[0251]
[Table 3]

[0252]
[Table 4]

[0253]
[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 area
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.
[0254]
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.
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.
[0255]
[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.
[0256]
[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.
(Triangle | delta): The small lump (aggregation) was recognized slightly.
X: A lump (aggregation) was clearly recognized.
[0257]
[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.
Regarding the charge amount, the initial charge amount under room temperature conditions (25 ° C, 45% humidity), the charge amount after printing 1,000 sheets (after 1K), and the charge amount under high temperature and high humidity conditions (30 ° C, humidity 85%) Asked.
[0258]
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.
○: Change amount (absolute value) from initial charge amount is 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.
[0259]
[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.
These results are summarized in Tables 5 and 6.
[0260]
[Table 5]

[0261]
[Table 6]

[0262]
As apparent from Table 5, the toners of the present invention were all excellent in development durability and exhibited excellent fixability in a wide temperature range. In addition, the toner of the present invention was excellent in storage stability and charging characteristics. In particular, the toner of the present invention exhibits excellent development durability, fixability, storage stability, and charging characteristics while maintaining transfer efficiency. In addition, extremely good results were obtained with a toner in which the composition of the polyester resin, the average particle diameter of the positively chargeable silica, and the ratio of the free external additive were in the preferred ranges.
[0263]
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 that does not contain positively-charged silica was particularly inferior in charging characteristics since the change in charge amount and the reverse charge amount after printing 1000 sheets were particularly large.
Further, in the toners of Comparative Examples 2 to 6 in which the acid value of the toner was higher than 8.0 KOHmg / g, the charge amount decrease under high temperature and high humidity was extremely severe.
In particular, the toner of Comparative Example 5 using an aromatic diol as the diol component constituting the polyester resin was inferior in durability because of the large friction coefficient of the resin.
[0264]
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 8, 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.
[0265]
Further, as a colorant, instead of quinacridone (PR 122), copper phthalocyanine pigment, 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 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 positively charged silica released from toner particles contained in toner.
FIG. 5 is an overall configuration diagram showing a preferred embodiment of the image forming apparatus of the present invention.
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 the peeling member with respect to a tangent line at the outlet of the nip portion.
FIG. 13 is a diagram schematically illustrating the shape of a fixing roller and a pressure roller and the shape of a 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 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.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Kneading machine 2 ... Process part 21 ... Barrel 22, 23 ... Screw 24 ... Fixing member 3 ... Head part 31 ... Internal space 32 ... Extrusion port 33 ... Cross-sectional area gradually decreasing part 4 ... Feeder 5 ... Raw material 6 ... Cooling machine 61, 62, 63, 64 ... Roll 611, 621, 631, 641 ... Rotating shaft 65, 66 ... Belt 67 ... Discharge section 7 ... Kneaded material 10 ... Image forming apparatus 20... 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 …… Regulating blade 605a …… Plate member 605b …… Elastic member 60Y …… Yellow developing device 60M …… Magenta developing device 60C …… Shear Developing device 60K …… Black developing device 70 …… 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 cassette 160... Pickup roller 170... Recording medium transport path 190 .. Fixing device 200 .. Discharge tray 210 .. Fixing roller (heat fixing member) 210a .. Heat source 210b. 210c ....... Elastic layer 210d .... Rotating shaft 220 ... Pressure roller (pressing member) 220b .... Cylinder 220c .... Elastic layer 220d .... Rotating shaft 230 ... Conveying path for double-sided printing 240 ... Housing 250 ... ... Bearing 260 ... Pressure lever 270 ... Pressure spring 280 ... Drive gear 290 …… Support shaft 300 …… Support shaft 310 …… Peeling member 310a …… Peeling part 310b …… Bending part 310c …… Supporting piece 310d …… Fitting hole 310e …… Guide part 310f …… Tip part 320 …… Peeling Member 320a …… Peeling part 320e …… Guide part 330 …… Spring 340 …… Nip part 341 …… Nip outlet 500 …… Recording medium T …… Toner S …… Tangent line G1 …… Gap G2 …… Gap

Claims (17)

A toner in which the resin component is composed of a material mainly composed of a polyester resin,
The alcohol component constituting the polyester-based resin is composed of a linear and / or cyclic aliphatic diol,
The polyester-based resin includes a block polyester 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 the alcohol component and a carboxylic acid component, and an amorphous block having lower crystallinity than the crystalline block,
Containing positively charged silica and rutile-anatase type titanium oxide,
A negatively chargeable toner having an acid value of 8.0 KOHmg / g or less.   The toner according to claim 1, wherein the polyester resin is non-crosslinked.   The toner according to claim 1, wherein an average particle diameter of primary particles of the positively chargeable silica is 30 to 200 nm.   The toner according to claim 1, wherein a content of the positively chargeable silica in the toner is 0.2 to 2.0 wt%.   The toner according to claim 1, wherein the positively chargeable silica is obtained by treating silica gel with a silane coupling agent having an amino group.   The toner according to claim 1, wherein the positively chargeable silica is added as an external additive.   The toner according to claim 6, wherein in addition to the positively chargeable silica, another external additive is further added.   The toner according to claim 7, comprising negatively-charged silica as the other external additive. The toner according to claim 8, wherein the positively-charged silica released from the surface of the toner particles functions as a microcarrier that is charged to a polarity opposite to that of the toner particles. A fixing roller;
A pressure roller pressed against the fixing roller;
A fixing device having a peeling member for peeling a recording medium that has passed through a fixing nip formed by a contact portion between the fixing roller and the pressure roller from the fixing roller, the resin component is mainly a polyester resin. An image forming method for forming an image by fixing toner composed of a material to a recording medium,
The alcohol component constituting the polyester-based resin is composed of a linear and / or cyclic aliphatic diol,
The polyester-based resin includes a block polyester 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 the alcohol component and a carboxylic acid component, and an amorphous block having lower crystallinity than the crystalline block,
Containing positively charged silica and rutile-anatase type titanium oxide,
An image forming method, wherein the toner has an acid value of 8.0 KOHmg / g or less.   The image forming method according to claim 10, wherein the fixing device has a recording medium feed speed of 0.05 to 1.0 m / sec.   The image forming method according to claim 10 or 11, wherein the peeling member is a plate-like member having a predetermined length in the axial direction of the fixing roller and / or the pressure roller.   13. The image forming method according to claim 10, wherein the fixing device has the peeling member disposed downstream of the fixing nip portion in the recording medium conveyance direction.   The image forming method according to claim 10, wherein the peeling member is disposed in proximity to the fixing roller and / or the pressure roller.   The image forming method according to claim 10, wherein the fixing device includes the fixing roller and the pressure roller arranged in a substantially horizontal state.   The image according to any one of claims 10 to 15, wherein the fixing device includes the peeling member so that a gap between the fixing roller and the peeling member is substantially constant during operation. Forming method.   17. The peeling member according to claim 10, wherein the peeling member is disposed along an axial direction of the fixing roller and has a shape that follows a shape of an outlet of the fixing nip portion. Image forming method.

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