JP4317379B2 - Toner production method - Google Patents

Description

【００１８】
で表される有機ホウ素化合物が好ましい。
【００１９】
式（Ｉ）で表される有機ホウ素化合物の市販品としては、「ＬＲ−１４７」（日本カーリット社製、ベンジル酸ホウ素化合物）等がある。
【００２０】
式（Ｉ）で表される有機ホウ素化合物の配合量は、結着樹脂１００重量部に対して、０．５〜５．０重量部が好ましく、１．０〜３．０重量部がより好ましい。
【００２１】
さらに、本発明による効果は、ワックスを多量に含有した、オイルレス定着に用いられるトナーを製造する場合により顕著に発揮される。また、工程数を削減し、生産効率を高める観点から、ワックスは、混合に供する原料に含まれているのが好ましい。
【００２２】
ワックスとしては、ポリプロピレンワックス、ポリエチレンワックス、フィッシャートロプッシュ等の合成ワックス、モンタンワックス等の石炭系ワックス、アルコール系ワックス等のワックスが挙げられ、特に限定されないが、本発明では、後述するヒドロキシ酸エステルを含有したワックスが好ましい。
【００２３】
ヒドロキシ酸エステルを含有したワックスとしては、カルナウバワックス、ライスワックス等の天然ワックス、セリル−ω−ヒドロキシセロテート（Ceryl-ω-hydroxycerotate) 、セリル−ω−ヒドロキシメリセート（Ceryl-ω-hydroxymelissate)、ミリシル−ω−ヒドロキシメリセート（Myricyl-ω-hydroxymelissate)等のヒドロキシ酸エステルを含有した合成ワックス等が挙げられる。ワックスにおけるヒドロキシ酸エステルの含有量は、２０重量％以上が好ましく、３０重量％以上がより好ましく、４０重量％以上が特に好ましく、５０重量％以上が最も好ましい。
【００２４】
ヒドロキシ酸エステルを含有したワックスの融点は、保存性及び耐オフセット性の観点から、好ましくは６５〜１１０℃、より好ましくは７０〜１００℃である。
【００２５】
ワックスの使用量は、結着樹脂１００重量部に対して、２〜３０重量部が好ましく、３〜２５重量部がより好ましく、５〜２０重量部が特に好ましい。なお、ヒドロキシ酸エステルを含有したワックスを用いる場合は、ヒドロキシ酸エステルの量が、耐オフセット性及び定着性の観点から、結着樹脂１００重量部に対して、好ましくは１重量部以上、より好ましくは２〜２５重量部、特に好ましくは２．５〜２０重量部となるように、ワックスの使用量を調整するのが望ましい。
【００２６】
本発明においては、さらに、着色剤、流動性向上剤、導電性調整剤、体質顔料、繊維状物質等の補強充填剤、酸化防止剤、老化防止剤、クリーニング性向上剤等の添加剤を原料として配合してもよい。
【００２７】
本発明における着色剤としては、トナー用着色剤として用いられている染料、顔料等のすべてを使用することができ、カーボンブラック、フタロシアニンブルー、パーマネントブラウンFG、ブリリアントファーストスカーレット、ピグメントグリーンＢ、ローダミン−Ｂベース、ソルベントレッド49、ソルベントレッド146 、ソルベントブルー35、キナクリドン、カーミン６Ｂ、ジスアゾエロー等が挙げられ、これらは単独で又は２種以上を混合して用いることができ、本発明により製造するトナーは、黒トナー、モノカラートナー、フルカラートナーのいずれであってもよい。着色剤の使用量は、結着樹脂１００重量部に対して、１〜４０重量部が好ましく、３〜１０重量部がより好ましい。
【００２８】
本発明は、結着樹脂、荷電制御剤等を含む原料を、〔装置フルード数×攪拌時間（ｓ）〕の値（以下、Ｆｒ・ｔ値という）が７５，０００〜４００，０００、好ましくは９０，０００〜３００，０００、より好ましくは１００，０００〜２６０，０００となる条件下で、混合する点に１つの特徴を有する。Ｆｒ・ｔ値が７５，０００未満であると、荷電制御剤の分散が不十分でベタ追従性が低下し、Ｆｒ・ｔ値が４００，０００を超えると、混合機内の温度の上昇により原料が溶融し、続く溶融混練工程に供することができなくなる。
【００２９】
なお、本発明において、フルード数（Ｆｒ）は、
【００３０】
【数１】

【００３１】
により求められる。ここで攪拌羽根の周速は、荷電制御剤の分散性及び混合物の過度な温度上昇の防止の観点から、１５〜４０ｍ／ｓが好ましく、２０〜３０ｍ／ｓがより好ましい。
【００３２】
本発明において、混合工程に用いられる混合機としては、攪拌羽根を備えた公知の混合機、例えば、ヘンシェルミキサー、スーパーミキサー等を特に限定することなく用いることができる。
【００３３】
攪拌羽根としては、ＳＴ羽根、Ｙ₁ 羽根、Ｚｏ羽根、ＳＲ羽根、ＣＫ羽根、Ｐｏ羽根、ＶＳ／ＶＬ羽根、Ｙ₁ 特羽根、ＰＥ羽根、Ｙｏ羽根（以上、三井鉱山社製）等の上羽根、Ａｏ羽根、Ｓｏ羽根、Ｂｏ羽根（以上、三井鉱山社製）等の下羽根、ＣＤ／ＣＤ羽根、ＣＲ／ＣＡ羽根（以上、三井鉱山社製）等の上下羽根が挙げられるが、これらの中では、分散性を向上させる観点から、上羽根としてＳＴ羽根、下羽根としてＡｏ羽根の組み合わせが好ましい。
【００３４】
本発明では、混合工程で得られた混合物の溶融混練をオープンロール型混練機で行う点にもう１つの特徴を有する。オープンロール型連続混練機を用いることにより、ワックスの微分散が可能となるため、特に、ワックスを多量に含有した原料を用いる場合は、成分層の分離もなく、本発明の効果がより顕著に発揮される。
【００３５】
なお、本発明で用いる原料は、混合工程及び溶融混練工程において分割投入してもよいが、工程数の削減し、生産効率を高める観点から、全ての原料を混合工程に一括投入することが好ましい。
【００３６】
本発明で用いるオープンロール型連続混練機としては、回転速度の異なる２本のロールを有する二本ロール型混練機であるのが好ましい。
【００３７】
ロールの回転速度は、回転速度が速い方のロール（高回転ロール）では、５０〜１５０ｒ／ｍｉｎが好ましく、５０〜１００ｒ／ｍｉｎがより好ましい。また、回転速度が遅い方のロール（低回転ロール）では、高回転ロールの回転速度よりも、１０〜７５ｒ／ｍｉｎ、より好ましくは１０〜３０ｒ／ｍｉｎ低回転であるのが好ましい。
【００３８】
混練物が高回転ロールに張りつきやすくするために、高回転ロールの原料投入側の温度は結着樹脂の軟化点及びワックスの融点のいずれの温度よりも高く、低回転ロールの温度は結着樹脂の軟化点及びワックスの融点のいずれの温度よりも低く調整されているのが好ましい。
【００３９】
高回転ロールの原料投入側の温度は、結着樹脂の軟化点及びワックスの融点のいずれの温度よりも高いことが好ましく、そのいずれかの高い方の温度よりも、０〜８０℃高いことがより好ましく、５〜５０℃高いことが特に好ましい。また、低回転ロールの温度は、結着樹脂の軟化点及びワックスの融点のいずれの温度よりも低いことが好ましく、そのいずれかの低い方の温度よりも、０〜８０℃低いことがより好ましく、４０〜８０℃低いことが特に好ましい。
【００４０】
高回転ロールと低回転ロールの温度の差は、６０〜１５０℃が好ましく、８０〜１２０℃がより好ましい。なお、ロールの温度は、ロール内部に通す熱媒体の温度により調整することができ、各ロールには、ロール内部を２以上に分割して温度の異なる熱媒体を通じてもよい。
【００４１】
２本のロールは互いに近接して配設されているのが好ましく、ロールの間隙は、０．０１〜５ｍｍが好ましく、０．０５〜２ｍｍがより好ましい。
【００４２】
ロールの構造、大きさ、材料等は特に限定されず、ロール表面も、平滑、波型、凸凹型等のいずれであってもよい。
【００４３】
次いで、得られた混練物を、粉砕可能な硬度に達するまで冷却した後、粉砕し、必要に応じて、分級することにより、トナーを得ることができる。本発明により得られるトナーの体積平均粒子径は、３〜１５μｍが好ましい。さらに、トナーの製造段階で得られる粗粉砕物やトナーの表面に、疎水性シリカ等の流動性向上剤等を外添してもよい。
【００４４】
本発明により得られるトナーは、磁性体微粉末を含有するときは単独で現像剤として、また磁性体微粉末を含有しないときは非磁性一成分系現像剤として、もしくはキャリアと混合して二成分系現像剤として、特に限定されることなく、いずれの現像方法にも用いることが出来る。
【００４５】
本発明により得られるトナーは、ワックスを多量に配合した場合であっても、ワックスをトナー中に微細に均一分散させることができるため、オイルレス定着に好適に用いることができる。オイルレス定着としては、オイル供給装置を備えていないヒートロール定着装置を有する印字装置等を用いた定着が挙げられるが、オイル供給装置とは、オイルタンクを有し、定量的にオイルをヒートロール表面に塗布する機構を有する装置の他、オイルを予め含浸させたロールをヒートロールに接触させるような機構を有する装置等を含む。
【００４６】
また、本発明によるトナーは、トナー飛散も少なく、微細な網点の再現性にも優れることから、正転現像のみならず、反転現像にも好適に用いることができる。
【００４７】
さらに、本発明によるトナーは、オイルレス定着に好適な、イエロートナー、シアントナー、マゼンタトナー等を用いたモノカラー画像やフルカラー画像等のカラー画像の形成にも好適に用いられる。
【００４８】
【実施例】
〔酸価及び水酸基価〕
ＪＩＳ Ｋ００７０の方法により測定する。
【００４９】
〔ガラス転移点及び融点〕
示差走査熱量計「ＤＳＣ２１０」（セイコー電子工業（株）製）を用いて昇温速度１０℃／分で測定する。
【００５０】
樹脂製造例１
ポリオキシプロピレン（２．２）−２，２−ビス（４−ヒドロキシフェニル）プロパン１０８００ｇ、ポリオキシプロピレン（２．０）−２，２−ビス（４−ヒドロキシフェニル）プロパン４３００ｇ、テレフタル酸４５００ｇ及びｎ−ドデセニル無水コハク酸６３０ｇを窒素雰囲気下、２３０℃で攪拌し、反応により生成する水が流出しなくなった時点で、無水トリメリット酸１８８０ｇを添加し、ＡＳＴＭ Ｄ３６−８６に準拠して測定した軟化点が１３０℃に達するまで反応させて、樹脂Ａを得た。樹脂Ａのガラス転移点は７４℃、酸価２５ｍｇＫＯＨ／ｇ、水酸基価は２６ｍｇＫＯＨ／ｇであった。
【００５１】
樹脂製造例２
ポリオキシプロピレン（２．２）−２，２−ビス（４−ヒドロキシフェニル）プロパン１２２５０ｇ、ポリオキシプロピレン（２．０）−２，２−ビス（４−ヒドロキシフェニル）プロパン２１１２５ｇ、テレフタル酸１４９４０ｇ及び酸化ジブチル錫１５ｇを窒素雰囲気下、２３０℃で攪拌し、ＡＳＴＭ Ｄ３６−８６に準拠して測定した軟化点が１２１℃に達するまで反応させて、樹脂Ｂを得た。樹脂Ｂのガラス転移点は６６℃、酸価３．４ｍｇＫＯＨ／ｇ、水酸基価は２３．４ｍｇＫＯＨ／ｇであった。
【００５２】
実施例１、２、比較例１、２
樹脂Ａ ２２８０ｇ、樹脂Ｂ ４３２０ｇ、ピグメント・ブルー１５：３（大日精化工業社製）２８８ｇ、ピグメント・グリーン７（大日精化工業社製）１５ｇ、ヒドロキシ酸エステル含有ワックス「カルナバワックスＣ１」（加藤洋行社製、ヒドロキシ酸エステル含有率：５３〜５５重量％、融点：約８７℃）５０４ｇ及び荷電制御剤「ＬＲ−１４７」（日本カーリット社製）８６．５ｇを、攪拌羽根として、上羽根にＳＴ羽根、下羽根にＡｏ羽根を備えたヘンシェルミキサーを用い、表１に示す条件下で混合をした後、下記のオープンロール型連続混練機で溶融混練した。
【００５３】
なお、使用したオープンロール型連続混練機は、ロール外径が０．１４ｍ、有効ロール長が０．８ｍのものであり、運転条件は、高回転側ロール（前ロール）の回転数が７５ｒ／ｍｉｎ、低回転側ロール（後ロール）の回転数が１５ｒ／ｍｉｎ、ロール間隙が０．１ｍｍであった。ロール内の加熱及び冷却媒体温度は、高回転ロールの原料投入側の温度を１５０℃、混練物排出側の温度を１１５℃、低回転ロールの原料投入側の温度を３５℃及び混練物排出側の温度を３０℃に設定した。また、原料混合物の供給速度は１０ｋｇ／時であった。
【００５４】
次に、溶融混練により得られた混練物を、ロートプレックスにて粗砕し、さらに得られた粗砕物８ｋｇと疎水性シリカ「Ｒ−９７２」（日本アエロジル社製）５６ｇとをヘンシェルミキサーで１分間攪拌混合した。
【００５５】
得られた攪拌混合物を、衝突板式粉砕機及びディスパージョンセパレータを用いて粉砕、分級を行い、体積平均粒子径が約８．０μｍの粉体を得た。
【００５６】
得られた粉体１．５ｋｇと、シリコーンオイルで疎水化処理されたシリカ「Ｓｉ−Ｎ」（日本アエロジル社製）５．３ｇ、ジクロロジメチルシランで疎水化処理されたシリカ「Ｒ−９７２」（日本アエロジル社製）７．５ｇ及びヘキサメチルジシラザンで疎水化処理されたシリカ「ＷＡＣＫＥＲ Ｈ１３ＴＭ」（クラリアントジャパン社製）７．５ｇとを、ヘンシェルミキサーにて３０００ｒ／ｍｉｎで１０分間混合し、得られた混合物を、目開き１０５μｍの振動篩にかけて、シアントナーを得た。
【００５７】
実施例３（参考例）
「カルナバワックスＣ１」の使用量を１８０ｇに変更し、オープンロール型連続混練機の代わりに二軸押出機で原料を溶融混練した以外は、実施例１と同様にして、シアントナーを得た。
【００５８】
試験例１
▲１▼ 現像カセットにトナー２３０ｇを量り取り、モーターにて１６０ｒ／ｍｉｎで１０分間なじみ運転を行った後、「ＢＥＡＭＳＴＡＲ４１２０」（日立製作所（株）製）でベタ画像を１枚採取した。次いで、印字率５．５％の斜めストライプパターンを１０００枚印刷し、その直後にベタ画像を１枚採取した。
▲２▼ 装置を一昼夜放置後、再び、１日目と同様にして、ベタ画像を１枚、印字率５．５％の斜めストライプパターンを１０００枚及びベタ画像を１枚採取した。
▲３▼ ▲２▼の操作を繰り返し、斜めストライプパターンの印刷枚数が６０００枚となるまで耐刷試験を行い、ベタ画像の印字先端部分と末端部分での画像濃度差を目視にて判断し、ベタ追従性を評価した。結果を表１に示す。
【００５９】
【表１】

【００６０】
以上の結果より、比較例１、２と対比して、所望の条件下で溶融混練を行った実施例１〜３では、ベタ追従性に優れたトナーが得られていることが分かる。
【００６１】
【発明の効果】
本発明により、ワックスを多量に含有するオイルレス定着に用いられるトナーであっても、ベタ追従性に優れたトナーを製造し得る方法を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method or the like.
[0002]
[Prior art]
Conventionally, in order to improve the dispersibility in a toner such as wax and charge adjusting agent, a method of producing toner with an open roll type continuous kneader is known (see Patent Documents 1 and 2).
[0003]
However, in recent years, the specifications of printers are increasing in speed and oilless fixing. For toners containing a large amount of wax, a charge control agent having a large particle size can be used even if such an open roll type continuous kneader is used. When it contains, there exists a fault that it is inferior to solid followability.
[0004]
In addition, as a means for improving the solid followability by improving the fluidity of the toner, a technique of adding two different types of external additives is known (see Patent Document 3). Due to the limitation, there is a drawback that the applicable range is narrow. Furthermore, in the case of the toner containing a large amount of wax as described above, sufficient solid followability may not be obtained.
[0005]
[Patent Document 1]
JP 2000-75543 A (Claim 1)
[Patent Document 2]
JP 2000-75548 A (Claim 1)
[Patent Document 3]
JP 2001-188384 A (Claim 1)
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a method capable of producing a toner excellent in solid followability even for a toner used for oilless fixing containing a large amount of wax.
[0007]
[Means for Solving the Problems]
The present invention is a toner manufacturing method comprising a step of mixing a raw material containing a binder resin and a charge control agent, and a step of melt-kneading the mixture obtained by the mixing step. X Stirring time (s)] relates to a method for producing a toner, which is carried out under conditions where the value is 75,000 to 400,000.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the binder resin used in the present invention include polyester, styrene-acrylic resin, mixed resin of polyester and styrene-acrylic resin, and hybrid resin in which two or more kinds of resin components are partially chemically bonded. From the viewpoint of the dispersibility of the agent, it is preferable to use polyester as a main component. The content of the polyester in the binder resin is preferably 50 to 100% by weight, and more preferably 70 to 100% by weight. The hybrid resin is preferably a resin in which a condensation polymerization resin such as polyester, polyester / polyamide, polyamide or the like and an addition polymerization resin such as vinyl polymerization resin are chemically bonded, and two or more kinds of resins are used as raw materials. In order to obtain a hybrid resin efficiently, two or more types of resins may be used. Those obtained from a mixture of raw material monomers are preferred.
[0009]
The raw material monomer of the polyester is not particularly limited, and a known alcohol component and a known carboxylic acid component such as carboxylic acid, carboxylic acid anhydride, or carboxylic acid ester are used.
[0010]
Examples of the alcohol component include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane. Bisphenol A alkylene (2 to 3 carbon atoms) oxide (average number of added moles 1 to 16) adduct, ethylene glycol, propylene glycol, glycerin, pentaerythritol, trimethylolpropane, hydrogenated bisphenol A, sorbitol, or alkylene thereof (C2-C4) oxide (average addition mole number 1-16) adduct etc. are mentioned.
[0011]
The carboxylic acid component includes dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid, adipic acid and succinic acid, alkyl groups having 1 to 20 carbon atoms such as dodecenyl succinic acid and octenyl succinic acid, or carbon. Trivalent or higher polyvalent carboxylic acids such as succinic acid, trimellitic acid and pyromellitic acid substituted with alkenyl groups of 2 to 20, anhydrides of these acids and alkyls of these acids (1 to 3 carbon atoms) ) Esters and the like.
[0012]
The polyester can be produced, for example, by subjecting an alcohol component and a carboxylic acid component to condensation polymerization at a temperature of 180 to 250 ° C. in an inert gas atmosphere, if necessary, using an esterification catalyst.
[0013]
When the toner obtained by the present invention is used as a positively chargeable toner, the acid value of the polyester is preferably 0.5 to 15 mgKOH / g, more preferably 1 to 12 mgKOH / g, and particularly preferably 1.5 to 10 mgKOH / g. preferable.
[0014]
When the toner is used as a negatively chargeable toner, the acid value of the polyester is preferably 5 to 40 mgKOH / g, more preferably 10 to 35 mgKOH / g, and particularly preferably 15 to 30 mgKOH / g.
[0015]
Moreover, the softening point of polyester is preferably 80 to 165 ° C, and the glass transition point is preferably 50 to 85 ° C.
[0016]
As the charge control agent used in the present invention, a positively chargeable charge control agent such as a nigrosine dye, a triphenylmethane dye containing a tertiary amine as a side chain, a quaternary ammonium salt compound, a polyamine resin, an imidazole derivative, Examples include metal-containing azo dyes, aromatic hydroxycarboxylic acid metal complexes, copper phthalocyanine dyes, metal complexes of alkyl derivatives of salicylic acid, and negatively chargeable charge control agents such as organoboron compounds, depending on the chargeability of the toner. Although they may be used alone or in combination, they may be used in particular.
[0017]
[Chemical formula 2]

[0018]
The organic boron compound represented by these is preferable.
[0019]
As a commercial item of the organic boron compound represented by the formula (I), there is “LR-147” (manufactured by Nippon Carlit Co., Ltd., benzyl acid boron compound).
[0020]
The compounding amount of the organoboron compound represented by the formula (I) is preferably 0.5 to 5.0 parts by weight, more preferably 1.0 to 3.0 parts by weight with respect to 100 parts by weight of the binder resin. .
[0021]
Furthermore, the effect of the present invention is more remarkable when a toner containing a large amount of wax and used for oilless fixing is produced. Moreover, it is preferable that the wax is contained in the raw material used for mixing from a viewpoint of reducing the number of processes and improving production efficiency.
[0022]
Examples of the wax include synthetic waxes such as polypropylene wax, polyethylene wax, and Fischer-Tropsch, coal-based waxes such as montan wax, and waxes such as alcohol-based waxes, and are not particularly limited. A wax containing is preferred.
[0023]
Hydroxyl ester-containing waxes include natural waxes such as carnauba wax and rice wax, Ceryl-ω-hydroxycerotate, Ceryl-ω-hydroxymelissate And synthetic waxes containing hydroxy acid esters such as myricyl-ω-hydroxymelissate. The content of the hydroxy acid ester in the wax is preferably 20% by weight or more, more preferably 30% by weight or more, particularly preferably 40% by weight or more, and most preferably 50% by weight or more.
[0024]
The melting point of the wax containing the hydroxy acid ester is preferably 65 to 110 ° C, more preferably 70 to 100 ° C, from the viewpoints of storage stability and offset resistance.
[0025]
The amount of the wax used is preferably 2 to 30 parts by weight, more preferably 3 to 25 parts by weight, and particularly preferably 5 to 20 parts by weight with respect to 100 parts by weight of the binder resin. When a wax containing a hydroxy acid ester is used, the amount of the hydroxy acid ester is preferably 1 part by weight or more, more preferably 100 parts by weight of the binder resin from the viewpoint of offset resistance and fixability. Is preferably adjusted to 2 to 25 parts by weight, particularly preferably 2.5 to 20 parts by weight.
[0026]
In the present invention, additives such as coloring agents, fluidity improvers, conductivity modifiers, extender pigments, reinforcing fillers such as fibrous substances, antioxidants, anti-aging agents, and cleanability improvers are used as raw materials. You may mix | blend as.
[0027]
As the colorant in the present invention, all of dyes and pigments used as toner colorants can be used, such as carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine- B base, Solvent Red 49, Solvent Red 146, Solvent Blue 35, Quinacridone, Carmine 6B, Disazo Yellow and the like can be used singly or in combination of two or more. , Black toner, mono-color toner, and full-color toner. The amount of the colorant used is preferably 1 to 40 parts by weight and more preferably 3 to 10 parts by weight with respect to 100 parts by weight of the binder resin.
[0028]
In the present invention, a raw material containing a binder resin, a charge control agent and the like has a [equipment fluid number × stirring time (s)] value (hereinafter referred to as Fr · t value) of 75,000 to 400,000, preferably It has one feature in that it is mixed under the conditions of 90,000 to 300,000, more preferably 100,000 to 260,000. When the Fr · t value is less than 75,000, dispersion of the charge control agent is insufficient and the solid followability is lowered. When the Fr · t value exceeds 400,000, the raw material is increased due to the temperature rise in the mixer. It cannot be used for the subsequent melt-kneading process.
[0029]
In the present invention, the Froude number (Fr) is
[0030]
[Expression 1]

[0031]
It is calculated by. Here, the peripheral speed of the stirring blade is preferably 15 to 40 m / s, more preferably 20 to 30 m / s, from the viewpoint of dispersibility of the charge control agent and prevention of an excessive temperature rise of the mixture.
[0032]
In the present invention, as a mixer used in the mixing step, a known mixer equipped with a stirring blade, for example, a Henschel mixer, a super mixer, or the like can be used without particular limitation.
[0033]
The stirring blade, ST blade, Y ₁ blade, Zo blade, SR blade, CK blade, Po blade, VS / VL blade, Y ₁ JP blade, PE blade, Yo blade (or, manufactured by Mitsui Mining Co., Ltd.) on such Lower blades such as blades, Ao blades, So blades, Bo blades (Mitsui Mining Co., Ltd.), upper and lower blades such as CD / CD blades, CR / CA blades (Mitsui Mining Co., Ltd.), etc. Among these, from the viewpoint of improving dispersibility, a combination of the ST blade as the upper blade and the Ao blade as the lower blade is preferable.
[0034]
The present invention has another feature in that the mixture obtained in the mixing step is melt kneaded with an open roll type kneader. By using an open roll type continuous kneader, it becomes possible to finely disperse the wax, and particularly when using a raw material containing a large amount of wax, there is no separation of the component layers, and the effect of the present invention is more remarkable. Demonstrated.
[0035]
The raw materials used in the present invention may be dividedly added in the mixing step and the melt-kneading step. However, it is preferable that all the raw materials are collectively added to the mixing step from the viewpoint of reducing the number of steps and increasing production efficiency. .
[0036]
The open roll type continuous kneader used in the present invention is preferably a two roll type kneader having two rolls having different rotational speeds.
[0037]
The rotation speed of the roll is preferably 50 to 150 r / min, and more preferably 50 to 100 r / min, in the roll having a higher rotation speed (high rotation roll). Moreover, in the roll with a slower rotation speed (low rotation roll), the rotation speed is preferably 10 to 75 r / min, more preferably 10 to 30 r / min lower than the rotation speed of the high rotation roll.
[0038]
In order to make the kneaded material easily stick to the high rotation roll, the temperature on the raw material input side of the high rotation roll is higher than the softening point of the binder resin and the melting point of the wax, and the temperature of the low rotation roll is the binder resin. The temperature is preferably adjusted to be lower than any of the softening point and the melting point of the wax.
[0039]
The temperature on the raw material charging side of the high-rotation roll is preferably higher than the softening point of the binder resin and the melting point of the wax, and is preferably 0 to 80 ° C. higher than the higher temperature. More preferably, it is particularly preferably 5 to 50 ° C. higher. Further, the temperature of the low rotation roll is preferably lower than any of the softening point of the binder resin and the melting point of the wax, and more preferably 0 to 80 ° C. lower than the lower one of them. 40 to 80 ° C. is particularly preferable.
[0040]
The temperature difference between the high rotation roll and the low rotation roll is preferably 60 to 150 ° C, more preferably 80 to 120 ° C. In addition, the temperature of a roll can be adjusted with the temperature of the heat medium passed through the inside of the roll, and the inside of the roll may be divided into two or more and a heat medium having a different temperature may be passed through each roll.
[0041]
The two rolls are preferably arranged close to each other, and the gap between the rolls is preferably 0.01 to 5 mm, more preferably 0.05 to 2 mm.
[0042]
The structure, size, material, and the like of the roll are not particularly limited, and the roll surface may be any of smooth, corrugated, uneven and the like.
[0043]
Next, the obtained kneaded product is cooled until reaching a pulverizable hardness, then pulverized, and classified as necessary, whereby a toner can be obtained. The volume average particle size of the toner obtained by the present invention is preferably 3 to 15 μm. Further, a fluidity improver such as hydrophobic silica may be externally added to the coarsely pulverized product obtained in the toner production stage or the surface of the toner.
[0044]
When the toner obtained by the present invention contains a magnetic fine powder, the toner alone is used as a developer, and when it does not contain a magnetic fine powder, the toner is a non-magnetic one-component developer or mixed with a carrier to form a two-component. The type developer is not particularly limited and can be used for any developing method.
[0045]
The toner obtained by the present invention can be suitably used for oilless fixing because the wax can be finely and uniformly dispersed in the toner even when a large amount of wax is blended. Examples of oilless fixing include fixing using a printing device having a heat roll fixing device that does not include an oil supply device. The oil supply device has an oil tank and quantitatively heats oil. In addition to a device having a mechanism for applying to the surface, a device having a mechanism for bringing a roll pre-impregnated with oil into contact with a heat roll is included.
[0046]
In addition, the toner according to the present invention has less toner scattering and excellent reproducibility of fine halftone dots, and therefore can be suitably used not only for forward development but also for reversal development.
[0047]
Furthermore, the toner according to the present invention is also suitably used for forming a color image such as a monocolor image or a full color image using a yellow toner, a cyan toner, a magenta toner or the like, which is suitable for oilless fixing.
[0048]
【Example】
[Acid value and hydroxyl value]
It is measured by the method of JIS K0070.
[0049]
[Glass transition point and melting point]
A differential scanning calorimeter “DSC210” (manufactured by Seiko Denshi Kogyo Co., Ltd.) is used to measure at a heating rate of 10 ° C./min.
[0050]
Resin production example 1
10800 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 4300 g of polyoxypropylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 4500 g of terephthalic acid and 630 g of n-dodecenyl succinic anhydride was stirred at 230 ° C. in a nitrogen atmosphere, and when water produced by the reaction stopped flowing out, 1880 g of trimellitic anhydride was added and measured according to ASTM D36-86. The resin A was obtained by reacting until the softening point reached 130 ° C. Resin A had a glass transition point of 74 ° C., an acid value of 25 mgKOH / g, and a hydroxyl value of 26 mgKOH / g.
[0051]
Resin production example 2
12250 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 21125 g of polyoxypropylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 14940 g of terephthalic acid and Resin B was obtained by stirring 15 g of dibutyltin oxide at 230 ° C. in a nitrogen atmosphere and reacting until the softening point measured in accordance with ASTM D36-86 reached 121 ° C. Resin B had a glass transition point of 66 ° C., an acid value of 3.4 mgKOH / g, and a hydroxyl value of 23.4 mgKOH / g.
[0052]
Examples 1 and 2 and Comparative Examples 1 and 2
Resin A 2280 g, Resin B 4320 g, Pigment Blue 15: 3 (manufactured by Dainichi Seika Kogyo Co., Ltd.) 288 g, Pigment Green 7 (manufactured by Dainichi Seika Kogyo Co., Ltd.) 15 g, hydroxy acid ester-containing wax “Carnauba Wax C1” Yoko Co., Ltd., hydroxy acid ester content: 53 to 55 wt%, melting point: about 87 ° C.) 504 g and charge control agent “LR-147” (manufactured by Nippon Carlit Co., Ltd.) 86.5 g as a stirring blade on the upper blade Using a Henschel mixer equipped with ST blades and Ao blades on the lower blades, mixing was performed under the conditions shown in Table 1, and then melt-kneading with the following open roll type continuous kneader.
[0053]
The open roll type continuous kneader used has a roll outer diameter of 0.14 m and an effective roll length of 0.8 m, and the operating condition is that the rotation speed of the high rotation side roll (front roll) is 75 r / min. min, the rotation speed of the low rotation side roll (rear roll) was 15 r / min, and the roll gap was 0.1 mm. The heating and cooling medium temperature in the roll is 150 ° C. on the raw material input side of the high-rotation roll, 115 ° C. on the kneaded material discharge side, 35 ° C. on the raw material input side of the low-rotation roll, and the kneaded material discharge side. Was set to 30 ° C. The feed rate of the raw material mixture was 10 kg / hour.
[0054]
Next, the kneaded material obtained by melt kneading is roughly crushed in a funnel plex. Further, 8 kg of the obtained coarsely crushed material and 56 g of hydrophobic silica “R-972” (manufactured by Nippon Aerosil Co., Ltd.) are mixed with a Henschel mixer. Stir and mix for a minute.
[0055]
The obtained stirred mixture was pulverized and classified using a collision plate type pulverizer and a dispersion separator to obtain a powder having a volume average particle diameter of about 8.0 μm.
[0056]
1.5 kg of the obtained powder, 5.3 g of silica “Si-N” (manufactured by Nippon Aerosil Co., Ltd.) hydrophobized with silicone oil, silica “R-972” hydrophobized with dichlorodimethylsilane ( Nippon Aerosil Co., Ltd.) (7.5 g) and hexamethyldisilazane hydrophobized silica “WACKER H13TM” (Clariant Japan Co., Ltd.) 7.5 g were mixed with a Henschel mixer for 10 minutes at 3000 r / min. The obtained mixture was passed through a vibrating sieve having an aperture of 105 μm to obtain a cyan toner.
[0057]
Example 3 (Reference Example)
A cyan toner was obtained in the same manner as in Example 1 except that the amount of “carnauba wax C1” was changed to 180 g and the raw material was melt-kneaded with a twin-screw extruder instead of the open roll type continuous kneader.
[0058]
Test example 1
{Circle around (1)} 230 g of toner was weighed into a developing cassette, and after a running-in operation at 160 r / min for 10 minutes with a motor, one solid image was collected with “BEAMSTAR 4120” (manufactured by Hitachi, Ltd.). Next, 1000 diagonal stripe patterns with a printing rate of 5.5% were printed, and immediately after that, one solid image was collected.
{Circle around (2)} After leaving the apparatus for a whole day and night, one solid image, 1000 oblique stripe patterns with a printing rate of 5.5%, and one solid image were again collected in the same manner as on the first day.
(3) Repeat the operation of (2), perform a printing durability test until the number of diagonal stripe patterns printed is 6000, visually determine the difference in image density between the front and end of the solid image, Solid followability was evaluated. The results are shown in Table 1.
[0059]
[Table 1]

[0060]
From the above results, it can be seen that, in comparison with Comparative Examples 1 and 2, in Examples 1 to 3 in which melt-kneading was performed under desired conditions, a toner having excellent solid followability was obtained.
[0061]
【The invention's effect】
According to the present invention, it is possible to provide a method capable of producing a toner excellent in solid followability even for a toner used for oilless fixing containing a large amount of wax.

Claims (4)

A toner production method comprising a step of mixing a raw material containing a binder resin, a charge control agent and a wax, and a step of melt-kneading the mixture obtained by the mixing step, wherein the wax comprises 100 parts by weight of the binder resin 2.5 to 20 parts by weight of a hydroxy acid ester, and the wax content is 5 to 20 parts by weight with respect to 100 parts by weight of the binder resin. A method for producing a toner, which is carried out under the condition that the value of the stirring time (s) is 100,000 to 260,000 . The method for producing a toner according to claim 1, wherein the wax has a melting point of 65 to 110 ° C.   The toner production method according to claim 1, wherein the melt-kneading step is performed using an open roll type continuous kneader. The charge control agent is of formula (I):

The method for producing a toner according to claim 1, wherein the toner is an organic boron compound represented by the formula: