JP4474561B2 - Carrier core material for electrophotographic developer, carrier powder for electrophotographic developer, and production method thereof - Google Patents
Carrier core material for electrophotographic developer, carrier powder for electrophotographic developer, and production method thereof Download PDFInfo
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Description
本発明は、電子写真の乾式現像法において用いられる電子写真現像剤用キャリア粉および当該電子写真現像剤用キャリア粉に用いられる電子写真現像剤用キャリア芯材、並びにそれらの製造方法に関する。 The present invention relates to a carrier powder for an electrophotographic developer used in an electrophotographic dry development method, a carrier core material for an electrophotographic developer used for the carrier powder for an electrophotographic developer, and a method for producing them.
電子写真の乾式現像法は、現像剤である粉体のトナーを感光体上の静電潜像に付着させ、当該付着したトナーを所定の紙等へ転写して現像する方法である。ここで、現像剤としては、トナーと電子写真現像剤用キャリア粉（以下、キャリア粉と記載する場合がある。）とを含む２成分系現像剤を用いる２成分系現像法と、トナーのみを含む１成分系現像剤を用いる１成分系現像法とに分けられる。そして、近年はトナーの荷電制御が容易で安定した高画質が得ることができ、高速現像が可能であることから殆どの場合、２成分系現像法が用いられている。そこで以下、この２成分系現像法について説明する。 The electrophotographic dry development method is a method in which a powder toner as a developer is attached to an electrostatic latent image on a photosensitive member, and the attached toner is transferred to a predetermined paper or the like for development. Here, as the developer, a two-component development method using a two-component developer including toner and carrier powder for electrophotographic developer (hereinafter sometimes referred to as carrier powder), and toner alone. And a one-component developing method using a one-component developer. In recent years, the charge control of toner is easy, a stable high image quality can be obtained, and high-speed development is possible. In most cases, a two-component development method is used. Therefore, this two-component development method will be described below.
２成分系現像法は、１成分系現像法と異なり、キャリア粉を用いてトナーを帯電させ、キャリア粉と伴にトナーを搬送するため、当該２成分系の電子複写機用現像剤に用いられるキャリア粉には、摩擦帯電性、磁気特性、耐久性、流動性など、様々な特性が要求される。中でも、電子写真の画質を左右する重要な要因として、キャリア粉とトナーとの摩擦帯電量が挙げられる。この摩擦帯電量が、所定値より低くなると画像の白紙部分にトナーが飛散する所謂カブリを生じコピー画質を低下させ、逆に所定値よりも高いと濃度の低い画質となってしまう。このため摩擦帯電量は、適正値に調整されていることが必要である。２成分系のキャリア粉においては、この摩擦帯電を調整しトナーに適宜な帯電量を付与させるためと、キャリア粉自体の機械的耐久性を確保するためとにより、磁性材料のソフトフェライトを含むキャリア芯材（以下、キャリア芯材と記載する場合がある。）の表面に樹脂を被覆してキャリア粉とすることが行われている。そして、この被覆樹脂の種類と膜厚とを適宜に選択することで、キャリア粉へ目標とする摩擦帯電量と機械的耐久性とを付与している。 Unlike the one-component development method, the two-component development method is used for the developer for the two-component electronic copying machine because the toner is charged using carrier powder and the toner is conveyed along with the carrier powder. The carrier powder is required to have various characteristics such as triboelectric chargeability, magnetic characteristics, durability, and fluidity. Among them, an important factor that affects the image quality of electrophotography is the amount of triboelectric charge between carrier powder and toner. When the triboelectric charge amount is lower than a predetermined value, so-called fogging in which toner is scattered on the blank paper portion of the image is generated, and the copy image quality is deteriorated. For this reason, the triboelectric charge amount needs to be adjusted to an appropriate value. In a two-component carrier powder, a carrier containing soft ferrite of a magnetic material is used to adjust the frictional charge and impart an appropriate amount of charge to the toner and to ensure the mechanical durability of the carrier powder itself. The surface of a core material (hereinafter sometimes referred to as a carrier core material) is coated with a resin to form carrier powder. Then, by appropriately selecting the type and film thickness of the coating resin, the target triboelectric charge amount and mechanical durability are imparted to the carrier powder.
一方、特許文献１には、被覆樹脂を有しないマグネタイトからなるキャリア粉についての提案が記載されている。そして、当該キャリア粉において、バナジウム化合物等をマグネタイトへ添加することで、当該マグネタイトひいては当該キャリア粉の摩擦帯電量を制御する構成について記載されている。 On the other hand, Patent Document 1 describes a proposal for carrier powder made of magnetite having no coating resin. In the carrier powder, a configuration is described in which the vanadium compound or the like is added to magnetite to control the friction charge amount of the magnetite and thus the carrier powder.
上述したキャリア芯材の表面に樹脂を被覆したキャリア粉を用いたとしても、被覆剤が有機物である樹脂であることから、例えば、長時間の連続印刷に伴う機械的摩擦に伴い、キャリア芯材から被覆剤の一部あるいは全部が剥がれてしまうことがある。こうなるとキャリア粉としての正常な摩擦帯電量を維持することが困難となるため、上述したカブリ現象を引き起こす上、当該被覆剤が剥がれたキャリア粉の割合がキャリア粉全体の、例えば３０％を超えるようになると、当該キャリア粉の全体が寿命を終えることとなる。 Even if the carrier powder having the resin coated on the surface of the carrier core is used, since the coating agent is an organic resin, for example, due to mechanical friction associated with continuous printing for a long time, the carrier core Some or all of the coating material may be peeled off. In this case, it becomes difficult to maintain a normal triboelectric charge amount as the carrier powder, so that the above-mentioned fog phenomenon is caused, and the ratio of the carrier powder from which the coating agent is peeled exceeds 30% of the entire carrier powder, for example. As a result, the entire carrier powder ends its life.
ところが近年、電子写真の更なる画質向上要請やキャリア粉への長寿命化要請が強まってきた。これらの要請に応える方法として、キャリア粉から被覆剤が剥がれることを阻止することが考えられる。しかし、長時間の連続印刷中のキャリア粉には大きな機械的摩擦力が懸かるため、限られた生産コストの中でキャリア粉からの被覆剤剥がれを完全に阻止するのは困難であった。 However, in recent years, there has been an increasing demand for further improvement in image quality of electrophotography and a longer life for carrier powder. As a method for meeting these requirements, it is conceivable to prevent the coating material from being peeled off from the carrier powder. However, since a large mechanical frictional force is applied to the carrier powder during continuous printing for a long time, it is difficult to completely prevent the coating material from peeling off from the carrier powder within a limited production cost.
そこで、本発明が解決しようとする課題は、カブリ現象を引き起こし難く、寿命が長いキャリア粉および当該キャリア粉に含まれるキャリア芯材、並びに、これらの製造方法を提供することである。 Therefore, the problem to be solved by the present invention is to provide a carrier powder that does not easily cause a fogging phenomenon and has a long life, a carrier core material contained in the carrier powder, and a manufacturing method thereof.
上述の課題を解決するため本発明者らは試行錯誤の末、発想を転換し、キャリア粉から被覆剤が剥がれることを阻止するのではなく、例えば、キャリア粉全体の１０〜５０％のキャリア粉から被覆剤が剥がれたとしても、電子写真の画質を低下させないキャリア粉を得ることができれば、電子写真の更なる画質向上に貢献でき、ひいてはキャリア粉の長寿命化にも貢献できるのではないかという全く新規な発想に想到した。即ち、キャリア粉から被覆剤の全部または一部が剥がれてキャリア芯材が剥き出しなったとしても、当該剥き出しになったキャリア芯材が、正常な被覆がされていた当時のキャリア粉の摩擦帯電量を担保することができれば、他の磁気特性等は当該キャリア芯材が発揮しているものであることから、正常なキャリア粉の機能の大部分を代替できるのではないかという発想に想到したのである。 In order to solve the above-mentioned problems, the present inventors changed the way of thinking after trial and error, and did not prevent the coating material from being peeled off from the carrier powder. For example, 10-50% of the carrier powder as a whole Even if the coating material is peeled off, if carrier powder that does not deteriorate the image quality of electrophotography can be obtained, it can contribute to further improvement of image quality of electrophotography, and in turn, contribute to longer life of carrier powder. I came up with a completely new idea. That is, even if all or part of the coating agent is peeled off from the carrier powder and the carrier core material is exposed, the amount of triboelectric charge of the carrier powder at the time when the exposed carrier core material was normally coated Since the carrier core material exhibits other magnetic properties, etc., we have come up with the idea that most of the functions of normal carrier powder can be replaced. is there.
ところが、従来の技術に係るソフトフェライトは、その摩擦帯電量を設定できる範囲の最高値が１９．５μＣ／ｇである。一方、２成分系のキャリア粉に求められる摩擦帯電量には、２０〜３０μC／gの幅があり、従来の技術に係るソフトフェライトでは、当該目的に使用するのに限界があった。 However, the soft ferrite according to the prior art has a maximum value of 19.5 μC / g within the range in which the triboelectric charge amount can be set. On the other hand, the triboelectric charge required for the two-component carrier powder has a range of 20 to 30 μC / g, and the soft ferrite according to the prior art has a limit to use for this purpose.
そこで、本発明らは、まず、２成分系のキャリア粉に求められる広範囲な摩擦帯電量に対応可能で、且つ、当該摩擦帯電量は広範囲な値に調整可能でありながら、当該調整を行っても磁気特性を始めとする他の特性は殆ど変化しないキャリア芯材およびその製造方法に想到し、さらには、当該キャリア芯材を用いたキャリア粉であって、当該キャリア粉から被覆剤の全部または一部が剥がれても、当該キャリア粉に求められる摩擦帯電量、磁気特性を始めとする様々な特性を維持できるキャリア粉およびその製造方法に想到することで上述の課題を解決することができた。 Therefore, the present invention is able to cope with a wide range of triboelectric charge required for a two-component carrier powder and perform the adjustment while the triboelectric charge can be adjusted to a wide range of values. In addition, the present inventors have conceived a carrier core material in which other characteristics such as magnetic characteristics hardly change, and a method for producing the same, and further, a carrier powder using the carrier core material, from the carrier powder to all or a coating agent. Even if a part of the carrier powder is peeled off, the above problems can be solved by conceiving a carrier powder capable of maintaining various characteristics including the triboelectric charge required for the carrier powder and magnetic characteristics, and a manufacturing method thereof. .
即ち、上述の課題を解決するための第１の手段は、
酸化鉄中に、Ｍｎ、Ｍｇから選択されるいずれか１種以上の元素を含むソフトフェライトを用いた電子写真現像剤用キャリア芯材であって、
前記ソフトフェライト中に、Ｃａ化合物が含有されていることを特徴とする電子写真現像剤用キャリア芯材である。
That is, the first means for solving the above-described problem is:
A carrier core material for an electrophotographic developer using soft ferrite containing one or more elements selected from Mn and Mg in iron oxide,
A carrier core material for an electrophotographic developer, wherein the soft ferrite contains a Ca compound.
第２の手段は、
前記ソフトフェライト中に、Ｃａ化合物がＣａ元素換算で０．０４〜０．８質量％含有されていることを特徴とする第１の手段に記載の電子写真現像剤用キャリア芯材である。
The second means is
The carrier core material for an electrophotographic developer according to the first means, wherein the soft ferrite contains a Ca compound in an amount of 0.04 to 0.8% by mass in terms of Ca element.
第３の手段は、
第１または第２の手段に記載の電子写真現像剤用キャリア芯材が、樹脂被覆されたものであることを特徴とする電子写真現像剤用キャリア粉。
The third means is
A carrier powder for an electrophotographic developer, wherein the carrier core material for an electrophotographic developer described in the first or second means is coated with a resin.
第４の手段は、
第３の手段に記載の電子写真現像剤用キャリア粉であって、
当該電子写真現像剤用キャリア粉の有する摩擦帯電量の値と、前記電子写真現像剤用キャリア芯材の有する摩擦帯電量の値とが、±10％以内の範囲で一致していることを特徴とする電子写真現像剤用キャリア粉である。
The fourth means is
The carrier powder for an electrophotographic developer according to the third means,
The value of the triboelectric charge possessed by the carrier powder for electrophotographic developer and the value of the triboelectric charge possessed by the carrier core material for electrophotographic developer are consistent within a range of ± 10%. A carrier powder for an electrophotographic developer.
第５の手段は、
酸化鉄中に、Ｍｎ、Ｍｇから選択されるいずれか１種以上の元素を含むソフトフェライトの原料中に、Ｃａ化合物とＣ化合物とを添加し混合して、調合原料を得る調合工程と、
調合原料を造粒しペレットを得る造粒工程と、
ペレットを焼成してソフトフェライトを得る焼成工程と、
ソフトフェライトを解砕して篩い分けし、キャリア芯材を得る篩分工程とを有することを特徴とする電子写真現像剤用キャリア芯材の製造方法である。
The fifth means is
In a raw material of soft ferrite containing one or more elements selected from Mn and Mg in iron oxide, a Ca compound and a C compound are added and mixed to obtain a blended raw material,
A granulation step of granulating the blended raw material to obtain pellets;
A firing step of firing pellets to obtain soft ferrite;
And a sieving step for obtaining a carrier core material by pulverizing and sieving soft ferrite, and a method for producing a carrier core material for an electrophotographic developer.
第６の手段は、
ソフトフェライトの原料中へ、Ｃａ化合物をＣａ元素換算で０．０４〜０．８質量％の添加し、且つ、Ｃ化合物をＣ元素換算で０．５〜１．０質量％添加することを特徴とする第５の手段に記載の電子写真現像剤用キャリア芯材の製造方法である。
The sixth means is
A Ca compound is added to a soft ferrite raw material in an amount of 0.04 to 0.8 mass% in terms of Ca element, and a C compound is added in an amount of 0.5 to 1.0 mass% in terms of C element. The method for producing a carrier core material for an electrophotographic developer according to the fifth means.
第７の手段は、
第５または第６の手段に記載の電子写真現像剤用キャリア芯材へ、樹脂を被覆して電子写真現像剤用キャリア粉を得る電子写真現像剤用キャリア粉の製造方法であって、
前記電子写真現像剤用キャリア粉の有する摩擦帯電量の値と、前記キャリア芯材の有する摩擦帯電量の値とが±10％以内の範囲で一致するように、前記Ｃａ化合物の添加量を設定することを特徴とする電子写真現像剤用キャリア粉の製造方法である。
The seventh means is
A method for producing a carrier powder for an electrophotographic developer obtained by coating a resin core on the carrier core material for an electrophotographic developer according to the fifth or sixth means to obtain a carrier powder for an electrophotographic developer,
The amount of Ca compound added is set so that the value of the triboelectric charge possessed by the carrier powder for electrophotographic developer and the value of the triboelectric charge possessed by the carrier core material are matched within a range of ± 10%. A method for producing a carrier powder for an electrophotographic developer.
第１の手段に係る電子写真現像剤用キャリア芯材は、当該電子写真現像剤用キャリア芯材の有する摩擦帯電量を、広範囲に渡って設定することができる。 In the carrier core material for electrophotographic developer according to the first means, the triboelectric charge amount of the carrier core material for electrophotographic developer can be set over a wide range.
第２の手段に係る電子写真現像剤用キャリア芯材は、当該電子写真現像剤用キャリア芯材の有する摩擦帯電量を、１１μＣから３４．６μＣという範囲において設定することができる。 In the carrier core material for electrophotographic developer according to the second means, the triboelectric charge amount of the carrier core material for electrophotographic developer can be set in the range of 11 μC to 34.6 μC.
第３の手段に係る電子写真現像剤用キャリア粉は、その摩擦帯電量と、当該電子写真現像剤用キャリア粉に含まれるキャリア芯材の摩擦帯電量とを略一致させることができる。 The carrier powder for electrophotographic developer according to the third means can substantially match the triboelectric charge amount with the triboelectric charge amount of the carrier core material contained in the electrophotographic developer carrier powder.
第４の手段に記載の電子写真現像剤用キャリア粉は、当該キャリア粉から被覆剤の全部または一部が剥がれても、当該電子写真現像剤用キャリア粉に求められる摩擦帯電量を維持できるので、電子写真の画質を低下させず、長寿命化された電子写真現像剤用キャリア粉である。 Since the carrier powder for an electrophotographic developer described in the fourth means can maintain the triboelectric charge required for the carrier powder for an electrophotographic developer even if all or part of the coating agent is peeled off from the carrier powder. The carrier powder for an electrophotographic developer has a long life without degrading the image quality of the electrophotography.
第５または第６の手段に記載の電子写真現像剤用キャリア芯材の製造方法によれば、摩擦帯電量は所定の値に調整可能でありながら、当該摩擦帯電量の調整を行っても磁気特性を始めとする他の特性は殆ど変化しないキャリア芯材を製造することができる。 According to the method of manufacturing the carrier core material for an electrophotographic developer described in the fifth or sixth means, the frictional charge amount can be adjusted to a predetermined value, but the magnetic charge can be adjusted even if the frictional charge amount is adjusted. A carrier core material can be produced in which other characteristics such as characteristics hardly change.
第７の手段に記載の電子写真現像剤用キャリア粉の製造方法によれば、当該キャリア粉から被覆剤の全部または一部が剥がれても、当該キャリア粉に求められる摩擦帯電量、磁気特性を始めとする様々な特性を維持できるので電子写真の画質を低下させず、長寿命化されたキャリア粉を製造することができる。 According to the method for producing a carrier powder for an electrophotographic developer described in the seventh means, even if all or part of the coating agent is peeled off from the carrier powder, the triboelectric charge amount and magnetic characteristics required for the carrier powder are obtained. Since various characteristics such as the beginning can be maintained, the carrier powder having a long life can be produced without deteriorating the image quality of electrophotography.
本発明に係るキャリア芯材は、Ｃａ化合物をＣａ元素換算で０．０４〜０．８質量％含有している。そして、本発明に係るキャリア粉は、当該キャリア芯材を樹脂被覆したもので、キャリア粉の有する摩擦帯電量の値とキャリア芯材自体の有する摩擦帯電量の値とを、±10％以内の範囲で一致させることができるものである。 The carrier core material according to the present invention contains a Ca compound in an amount of 0.04 to 0.8% by mass in terms of Ca element. The carrier powder according to the present invention is obtained by coating the carrier core material with a resin, and the value of the friction charge amount of the carrier powder and the value of the friction charge amount of the carrier core material itself are within ± 10%. It can be matched in range.
まず、本発明に係るキャリア芯材の製造工程の好ましい例について、Ｍｎ系ソフトフェライトを用いた場合を例示しながら説明するが、本発明に係るキャリア芯材に用いるソフトフェライトとしては、マンガンフェライト、マグネシウムフェライト、マンガンマグネシウムフェライト等、多様な軟磁性体を用いることができる。 First, a preferred example of the manufacturing process of the carrier core material according to the present invention will be described while exemplifying the case where Mn-based soft ferrite is used. As the soft ferrite used for the carrier core material according to the present invention, manganese ferrite, Various soft magnetic materials such as magnesium ferrite and manganese magnesium ferrite can be used.
［原料粉の調合］
ソフトフェライトを構成する各成分の原料調合にあたり、Ｍｎ源としてはＭｎ３Ｏ４やＭｎＣＯ３、Ｆｅ源としてはＦｅ２Ｏ３を準備した。そして、ソフトフェライト中のＭｎ及びＦｅの組成比が、意図するソフトフェライトの組成比に相当するように、各原料を秤量する。さらに、Ｃａ源としては所定量のＣａＣＯ３、Ｃ源としてはカーボンブラック（以下、ＣＢと記載する。）を秤量する。これらの原料を十分に混合して調合するが、混合方法は、乳鉢等の使用による通常の混合で良い。配合されたＣａＣＯ３は、後述する焼成工程で分解および酸化してＣａ酸化物になり、また、ＣＢはＣＯ２になると考えられる。
[Formulation of raw material powder]
In preparing the raw materials for each component constituting soft ferrite, Mn 3 O 4 and MnCO 3 were prepared as the Mn source, and Fe 2 O 3 was prepared as the Fe source. Each raw material is weighed so that the composition ratio of Mn and Fe in the soft ferrite corresponds to the intended composition ratio of soft ferrite. Furthermore, a predetermined amount of CaCO 3 is measured as the Ca source, and carbon black (hereinafter referred to as CB) is measured as the C source. Although these raw materials are mixed well and prepared, the mixing method may be ordinary mixing by using a mortar or the like. It is considered that the blended CaCO 3 is decomposed and oxidized into a Ca oxide in the firing step described later, and CB is converted to CO 2 .
尚、フェライトとしてマグネシウムフェライトを選択する場合は、Ｍｇ源としてはＭｇＯやＭｇ(ＯＨ)２、ＭｇＣＯ３、Ｆｅ源としてはＦｅ２Ｏ３を用いれば良く、マンガンマグネシウムフェライトを選択する場合は、Ｍｎ源としてはＭｎ３Ｏ４やＭｎＯ、Ｍｇ源としてはＭｇＯやＭｇ(ＯＨ)２、ＭｇＣＯ３、Ｆｅ源としてはＦｅ２Ｏ３を用いれば良い。その後の工程は、Ｍｎフェライトの場合と同様に製造することができる。また、Ｃａ源としてはＣａＣＯ３の他にＣａＯ等が好適に使用でき、Ｃ源としてはＣＢの他に、ポリビニルアルコール（ＰＶＡ）、グラファイト、ポリアクリルアミド、アセチレン等が好適に使用できる。そして、いずれの原料を用いた場合でも、以下に説明するマンガンフェライトの製造工程と同様の製造工程で、各フェライトを製造することができる。 When magnesium ferrite is selected as the ferrite, MgO or Mg (OH) 2 or MgCO 3 may be used as the Mg source, and Fe 2 O 3 may be used as the Fe source. When manganese magnesium ferrite is selected, Mn The source may be Mn 3 O 4 or MnO, the Mg source may be MgO, Mg (OH) 2 or MgCO 3 , and the Fe source may be Fe 2 O 3 . Subsequent steps can be produced in the same manner as in the case of Mn ferrite. In addition to CaCO 3 , CaO or the like can be suitably used as the Ca source, and as the C source, polyvinyl alcohol (PVA), graphite, polyacrylamide, acetylene or the like can be suitably used in addition to CB. And even if any raw material is used, each ferrite can be manufactured with the manufacturing process similar to the manufacturing process of the manganese ferrite demonstrated below.
［粉砕・造粒工程］
調合した原料を水と混合し、更に必要に応じてポリカルボン酸等の分散剤を混合し、原料の配合比で６０〜９０質量％程度のスラリーとし、これをボールミル等で湿式粉砕する。
当該湿式粉砕により、微細に粉砕された原料のスラリーが得られる。この原料のスラリーを噴霧乾燥機等で噴霧乾燥するか、或いはペレタイザーで造粒し、径が１０〜５００μｍの球状ペレットにして乾燥する。
[Crushing and granulating process]
The prepared raw material is mixed with water, and further a dispersing agent such as polycarboxylic acid is mixed as necessary to obtain a slurry having a raw material mixing ratio of about 60 to 90% by mass, and this is wet pulverized with a ball mill or the like.
By the wet pulverization, a finely pulverized raw material slurry is obtained. The slurry of this raw material is spray-dried with a spray dryer or the like, or granulated with a pelletizer, and dried into spherical pellets having a diameter of 10 to 500 μm.
［焼成工程］
次いで、前記球状ペレットを焼成してソフトフェライトとするが、その際、電気炉にて窒素ガス雰囲気中、１０００〜１５００℃の温度で焼成処理を行う。当該焼成において、原料中のＣ化合物はＣＯ２となるが、Ｃの添加割合が、Ｃ元素換算で０．５質量％以上あれば焼結性が向上し、１．０質量％以下であれば、焼結性が進みすぎて粒子の球状性を維持することが困難になるのを回避できるので好ましい。
[Baking process]
Next, the spherical pellets are fired to form soft ferrite. At that time, firing is performed at a temperature of 1000 to 1500 ° C. in a nitrogen gas atmosphere in an electric furnace. In the firing, the C compound in the raw material becomes CO 2 , but if the addition ratio of C is 0.5% by mass or more in terms of C element, the sinterability is improved, and if it is 1.0% by mass or less. It is preferable because it is possible to avoid the difficulty of maintaining the spherical shape of the particles due to excessive progress of sinterability.
［篩分工程］
焼成されたソフトフェライトを解砕機で解砕して解砕粉とし、当該解砕粉を分級または篩分けして所定の粒度を有するものを採取し、キャリア芯材とする。これにより、例えば平均粒子径が２０〜１２０μｍの範囲、好ましくは６０μｍ程度のソフトフェライト粒子を含む、見掛け密度が、２〜３ｇ／ｃｍ３の範囲のキャリア芯材を製造することができる。
[Sieving process]
The fired soft ferrite is crushed by a pulverizer to obtain a pulverized powder, and the pulverized powder is classified or sieved to collect a powder having a predetermined particle size to obtain a carrier core material. Thereby, for example, a carrier core material having an apparent density of 2 to 3 g / cm 3 including soft ferrite particles having an average particle diameter of 20 to 120 μm, preferably about 60 μm can be produced.
［樹脂被覆工程］
次に、上記得られたキャリア芯材へ樹脂被覆を行って、電子写真現像用キャリア粉（以下、キャリア粉と記載する。）を製造する工程について説明する。
キャリア芯材に樹脂被覆を施してキャリア粉を製造する場合、その樹脂被覆量はキャリア芯材総重量の０．５〜５．０質量％に調整するのがよい。被覆する樹脂としては種々のものが適用でき、例えばアクリル系樹脂、スチレン系樹脂、スチレン−アクリル系樹脂、オレフィン樹脂（ポリエチレン、塩素化ポリエチレン、ポリプロピレン等）、ポリエステル系樹脂（ポリエチレンテレフタレート、ポリカーボネート等）、不飽和ポリエステル系樹脂、塩化ビニル系樹脂、ポリアミド系樹脂、ポリウレタン系樹脂、エポキシ系樹脂、シリコーン系樹脂、フッ素系樹脂（ポリテトラフルオロエチレン、ポリクロロトリフルオロエチレン、ポリ弗化ビニリデン等）、フェノール系樹脂、キシレン系樹脂、ジアリルフタレート系樹脂等が挙げられる。
[Resin coating process]
Next, a process for producing a carrier powder for electrophotographic development (hereinafter referred to as carrier powder) by applying resin coating to the obtained carrier core material will be described.
When a carrier powder is produced by applying a resin coating to the carrier core material, the resin coating amount is preferably adjusted to 0.5 to 5.0 mass% of the total weight of the carrier core material. Various resins can be applied as coating resins, such as acrylic resins, styrene resins, styrene-acrylic resins, olefin resins (polyethylene, chlorinated polyethylene, polypropylene, etc.), polyester resins (polyethylene terephthalate, polycarbonate, etc.). , Unsaturated polyester resins, vinyl chloride resins, polyamide resins, polyurethane resins, epoxy resins, silicone resins, fluorine resins (polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, etc.), Examples thereof include phenolic resins, xylene resins, diallyl phthalate resins, and the like.
樹脂被覆を行うには、前記の所定樹脂を溶剤に希釈してキャリア芯材の表面に被覆するのが一般的である。溶剤としては所定樹脂が可溶なものであればよく、所定樹脂が有機溶剤に可溶な樹脂の場合、溶剤としてはトルエン、キシレン、メチルエチルケトン、メチルイソブチルケトン、メタノール等を使用することができ、所定樹脂が水溶性樹脂またはエマルジョンタイプの樹脂であれば、水を用いることができる。 In order to perform resin coating, it is common to dilute the predetermined resin in a solvent and coat the surface of the carrier core material. As long as the predetermined resin is soluble as the solvent, if the predetermined resin is a resin soluble in an organic solvent, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, methanol, etc. can be used as the solvent. If the predetermined resin is a water-soluble resin or an emulsion type resin, water can be used.
適宜な溶剤で希釈した所定樹脂を、キャリア芯材の表面へ被覆するには、浸漬法、スプレー法、刷毛塗り法等が適用できる。所定樹脂が被覆されたキャリア芯材を乾燥させるとキャリア粉を得ることができる。このような湿式法による樹脂被覆の他、キャリア芯材表面に所定樹脂粉末を付着させる乾式法によってもキャリア粉を得ることができる。 In order to coat the surface of the carrier core material with a predetermined resin diluted with an appropriate solvent, a dipping method, a spray method, a brush coating method, or the like can be applied. When the carrier core material coated with the predetermined resin is dried, carrier powder can be obtained. In addition to resin coating by such a wet method, carrier powder can also be obtained by a dry method in which a predetermined resin powder is adhered to the surface of the carrier core material.
上記、湿式法、乾式法のいずれにしても、キャリア芯材の表面に被覆した所定樹脂を焼きつけるのが好ましい。そこで、固定式または流動式の電気炉、ロータリー式電気炉、バーナー炉などを使用して、外部加熱方式または内部加熱方式で、キャリア芯材の表面に被覆された所定樹脂を焼きつけることが好ましい。尚、マイクロウェーブによる焼きつけも可能である。焼きつけ温度は所定樹脂によって異なるが、融点以上またはガラス転移点以上の温度が必要である。所定樹脂が、熱硬化性樹脂または縮合型樹脂である場合は、硬化が十分に進む温度にまで上げる必要がある。 Regardless of the wet method or the dry method, it is preferable to bake the predetermined resin coated on the surface of the carrier core material. Therefore, it is preferable to bake the predetermined resin coated on the surface of the carrier core material by an external heating method or an internal heating method using a fixed or fluid electric furnace, a rotary electric furnace, a burner furnace, or the like. Note that microwave baking is also possible. The baking temperature varies depending on the predetermined resin, but a temperature higher than the melting point or higher than the glass transition point is required. When the predetermined resin is a thermosetting resin or a condensation type resin, it is necessary to raise the temperature to a temperature at which the curing proceeds sufficiently.
ここで、所定樹脂としてシリコーン樹脂を選択し、キャリア芯材へ被覆を施す場合を例として、具体的に説明する。
まず、シリコーン樹脂をトルエンで希釈するが、例えばシリコーン樹脂の割合が、キャリア芯材総重量の３質量％となるように配合し、この液とキャリア芯材とを撹拌機に入れて撹拌する。この場合、必要に応じて硬化剤を添加する。撹拌混合を終えたら、樹脂の液が被覆されたキャリア芯材へ、例えば１９０℃×３０分の加熱処理して溶媒を乾燥除去する。ついで加熱処理後の樹脂被覆されたキャリア芯材を、オーブンまたはトンネル炉を用いて、例えば１６９〜２８０℃×３時間の熱処理を行い、シリコーン樹脂の焼きつけ処理を行う。これによりキャリア粉が得られる。
Here, the case where a silicone resin is selected as the predetermined resin and the carrier core material is coated will be specifically described as an example.
First, the silicone resin is diluted with toluene. For example, the silicone resin is blended so that the ratio of the silicone resin is 3% by mass of the total weight of the carrier core material, and this liquid and the carrier core material are put into an agitator and stirred. In this case, a curing agent is added as necessary. After the stirring and mixing, the carrier core material coated with the resin liquid is subjected to a heat treatment, for example, at 190 ° C. for 30 minutes to remove the solvent by drying. Subsequently, the resin-coated carrier core material after the heat treatment is subjected to a heat treatment of, for example, 169 to 280 ° C. for 3 hours using an oven or a tunnel furnace to perform a baking treatment of the silicone resin. Thereby, carrier powder is obtained.
［本発明に係る電子写真現像剤用キャリア芯材］
ここで、本発明に係るキャリア芯材について説明する。
本発明に係るキャリア芯材に含まれるソフトフェライト中のＣａの含有割合が０．０４質量％以上あると、ソフトフェライトの摩擦帯電量がＣａの含有割合に応じて増加する効果があり、Ｃａの含有割合が０．８質量％以下であれば、当該ソフトフェライトを含むキャリア芯材において他の特性変化が起きるのを回避できるので好ましい。
[Carrier Core Material for Electrophotographic Developer According to the Present Invention]
Here, the carrier core material according to the present invention will be described.
When the Ca content in the soft ferrite contained in the carrier core according to the present invention is 0.04% by mass or more, there is an effect that the triboelectric charge amount of the soft ferrite increases according to the Ca content. A content ratio of 0.8% by mass or less is preferable because other characteristic changes can be avoided in the carrier core material containing the soft ferrite.
具体的には実施例にて説明するが、本発明に係るキャリア芯材が、ソフトフェライトの原料として（ＭｎＯ）：（Ｆｅ２Ｏ３）＝３５：６５（モル比）の混合粉と、当該混合粉に対するＣの添加割合がＣ元素換算で０．６質量％となる組成で造粒、焼成したとき、当該キャリア芯材がＣａを含有しない場合は、摩擦帯電量が４．２μＣ／ｇであったのに対し、ＣａＣＯ３をＣａ換算で０．３質量％、０．６質量％および０．８質量％添加した場合は、摩擦帯電量は１１．１μＣ／ｇから３４．６μＣ／ｇまで増加した。即ち、当該キャリア芯材のＣａ添加量を制御するだけで摩擦帯電量を３４．６μＣ／ｇ迄の範囲で自在に設定できることが判明した。 Specifically, the carrier core material according to the present invention is a mixed powder of (MnO) :( Fe 2 O 3 ) = 35: 65 (molar ratio) as a soft ferrite raw material, When the carrier core material does not contain Ca when granulated and fired with a composition in which the addition ratio of C to the mixed powder is 0.6% by mass in terms of C element, the triboelectric charge amount is 4.2 μC / g. In contrast, when CaCO 3 was added in an amount of 0.3%, 0.6% and 0.8% by weight in terms of Ca, the triboelectric charge amount was 11.1 μC / g to 34.6 μC / g. Increased. That is, it has been found that the triboelectric charge amount can be freely set in the range of up to 34.6 μC / g simply by controlling the Ca addition amount of the carrier core material.
さらに、キャリア芯材が、ソフトフェライトの原料として（ＭｎＯ）：（Ｆｅ２Ｏ３）＝４０：６０（モル比）の混合粉と、当該混合粉に対するＣの添加割合がＣ元素換算で０．７質量％となる組成で造粒、焼成したとき、当該キャリア芯材がＣａＣＯ３をＣａ換算で１．０質量％から２．０質量％まで添加した場合は、摩擦帯電量は２３．８μＣ／ｇから２９．９μＣ／ｇまで増加した。即ち、当該キャリア芯材のＣａ添加量を制御するだけで摩擦帯電量を少なくとも２３．８μＣ／ｇ〜２９．９μＣ／ｇの範囲で自在に設定できることが判明した。
尚、当該キャリア芯材中のＣａ含有量が同一であるときは、（ＭｎＯ）：（Ｆｅ２Ｏ３）＝４０：６０（モル比）の方が、（ＭｎＯ）：（Ｆｅ２Ｏ３）＝３５：６５（モル比）の場合より摩擦帯電量が大きいことも判明した。
Furthermore, the carrier core material is a mixed powder of (MnO) :( Fe 2 O 3 ) = 40: 60 (molar ratio) as a raw material for soft ferrite, and the addition ratio of C to the mixed powder is 0. When the carrier core material is granulated and fired with a composition of 7% by mass, when the CaCO 3 is added from 1.0% by mass to 2.0% by mass in terms of Ca, the triboelectric charge is 23.8 μC / increased from g to 29.9 μC / g. That is, it has been found that the triboelectric charge amount can be freely set in a range of at least 23.8 μC / g to 29.9 μC / g only by controlling the Ca addition amount of the carrier core material.
When the Ca content in the carrier core material is the same, (MnO) :( Fe 2 O 3 ) = 40: 60 (molar ratio) is (MnO) :( Fe 2 O 3 ). It was also found that the triboelectric charge amount was larger than in the case of = 35: 65 (molar ratio).
一方、上述のキャリア芯材において、ＣａＣＯ３をＣａ換算で１．０質量％から２．０質量％まで添加した場合でも、コア見掛密度、飽和磁化および流動度といった特性に、大きな影響を与えていないことが分かった。従って、キャリア芯材においてＣａＣＯ３をＣａ換算で０．０４〜０．８質量％の範囲で添加量を制御することにより、他の特性を大きく変えることなく摩擦帯電量が制御されたキャリア芯材を得ることができた。 On the other hand, even when CaCO 3 is added from 1.0% by mass to 2.0% by mass in terms of Ca in the above-described carrier core material, the core apparent density, saturation magnetization and fluidity are greatly affected. I found out. Therefore, by controlling the amount of CaCO 3 added in the range of 0.04 to 0.8% by mass in terms of Ca in the carrier core material, the carrier core material in which the triboelectric charge amount is controlled without greatly changing other characteristics. Could get.
［本発明に係る電子写真現像剤用キャリア粉］
本発明に係るキャリア粉について説明する。
従来の技術に係るキャリア粉においては、従来の技術に係るキャリア芯材に塗布された樹脂の種類や膜厚等により、摩擦帯電量等の物性値が制御されており、その範囲は２０〜３０μＣ／ｇで設定されていた。このため、キャリア粉とキャリア芯材との摩擦帯電量等とは、大きく異なっており、長時間の連続使用に伴う劣化により、キャリア粉の表面樹脂の一部または全部が剥がれると、当該キャリア粉の摩擦帯電量等は大きく変化していた。そして、この摩擦帯電量等が大きく変化したキャリア粉が、電子写真の画質低下の原因となっていた。ここで本発明に係るキャリア芯材を準備し、当該キャリア芯材とキャリア粉との摩擦帯電量とを±10％の範囲内で一致させておけば、キャリア粉の使用に伴う劣化により表面樹脂の一部または全部が剥がれ、キャリア芯材が剥き出しになったとしても当該キャリア粉の摩擦帯電量等は大きく変化することがなく、電子写真の画質低下が起こらないという効果を上げることができ、さらに当該効果により、キャリア粉全体の１０〜５０％程度で表面樹脂の一部または全部の剥がれが起きても、当該キャリア粉を使用し続けることが可能になったため、当該キャリア粉の寿命を１２０〜１５０％程、延長することが可能となった。
[Carrier powder for electrophotographic developer according to the present invention]
The carrier powder according to the present invention will be described.
In the carrier powder according to the conventional technology, the physical property values such as the triboelectric charge amount are controlled by the type and film thickness of the resin applied to the carrier core material according to the conventional technology, and the range is 20 to 30 μC. / G. For this reason, the amount of triboelectric charge between the carrier powder and the carrier core material is greatly different, and when a part or all of the surface resin of the carrier powder is peeled off due to deterioration due to continuous use for a long time, the carrier powder The amount of triboelectric charge and the like greatly changed. Then, the carrier powder whose frictional charge amount and the like are greatly changed has caused a reduction in image quality of electrophotography. Here, if the carrier core material according to the present invention is prepared and the triboelectric charge amount of the carrier core material and the carrier powder is matched within a range of ± 10%, the surface resin is deteriorated due to the use of the carrier powder. Even if part or all of the above is peeled off and the carrier core material is exposed, the triboelectric charge amount of the carrier powder does not change greatly, and the effect that the image quality of electrophotography does not deteriorate can be improved, Furthermore, even if a part or all of the surface resin is peeled off at about 10 to 50% of the entire carrier powder, the effect makes it possible to continue using the carrier powder. It became possible to extend about 150%.
以下、実施例を参照しながら本発明をより具体的に説明する。
〔実施例１〕
Ｍｎ原料としてＭｎ３Ｏ４を、またＦｅ原料としてＦｅ２Ｏ３を準備する。そして、焼成後のソフトフェライト組成比として（ＭｎＯ）：（Ｆｅ２Ｏ３）＝３５：６５（モル比）となる割合でこれらの原料を調合し混合粉とした。この混合粉に対して、１．５質量％のポリカルボン酸系分散剤と、水とを加えて、スラリー濃度８４質量％程度のスラリーとした。このスラリーへ、ＣａＣＯ３及びＣを添加した。ＣａＣＯ３の添加量は、混合粉に対するＣａの割合がＣａ元素換算で０．３質量％となる量（ＣａＣＯ３の添加量で、０．７５質量％）とし、Ｃの添加量は混合粉に対するＣの割合がＣ元素換算で０．６質量％となる量（ＣＢの添加量で、０．６質量％）とした。
Hereinafter, the present invention will be described more specifically with reference to examples.
[Example 1]
Mn 3 O 4 is prepared as the Mn raw material, and Fe 2 O 3 is prepared as the Fe raw material. Then, these raw materials were blended at a ratio of (MnO) :( Fe 2 O 3 ) = 35: 65 (molar ratio) as the soft ferrite composition ratio after firing to obtain a mixed powder. A 1.5% by mass polycarboxylic acid-based dispersant and water were added to the mixed powder to obtain a slurry having a slurry concentration of about 84% by mass. To this slurry, CaCO 3 and C were added. The amount of CaCO 3 added is such that the ratio of Ca to the mixed powder is 0.3 mass% in terms of Ca element (the amount of CaCO 3 added is 0.75 mass%), and the amount of C added is based on the mixed powder. The amount of C was 0.6% by mass in terms of C element (the amount of CB added was 0.6% by mass).
次いで、これらの化合物を添加したスラリーを、湿式ボールミルに充填して湿式粉砕し、得られた懸濁液をスプレードライヤーで造粒した後、８２μｍの篩を用いて平均粒径が７０μｍ程度の乾燥粒子を有する造粒品を得た。 Next, the slurry to which these compounds are added is filled in a wet ball mill and wet pulverized. The resulting suspension is granulated with a spray dryer, and then dried with an average particle size of about 70 μm using a 82 μm sieve. A granulated product having particles was obtained.
この造粒品を焼成炉に充填し、窒素ガス雰囲気中にて１１８０℃で４時間焼成し、塊状の焼成品を得た。得られた焼成品をハンマーミルで粉砕し、この粉砕物を風力分級機にかけて微粉部分を分級除去し、次に磁場選鉱して非磁性部分を分離し、さらに７０μｍの篩を通して平均粒径６０μｍのキャリア芯材を得た。
得られたキャリア芯材の摩擦帯電量は、５０ｃｃの共栓試験管に被測定キャリア芯材１９ｇとトナー１ｇとを入れ、２０分間振とうし、振とう後の被測定キャリア芯材の摩擦帯電量をブローオフ帯電量測定装置（東芝ケミカル株式会社製）を用いて測定した。
静抵抗値の測定は、被測定キャリア芯材を、直径１２．９ｍｍφの絶縁性のパイプに正確に５ｇ充填し、２６５ｇの重りで圧力を掛けて、パイプの上下に設置された電極に接続した超絶縁計（東亜電波工業株式会社製）を用いて測定した。
コア見掛密度および流動度の測定は、ＪＩＳ規格に従って測定した。
飽和磁化の測定は、室温専用振動試料型磁力計（ＶＳＭ）（東英工業株式会社製）により測定した。
キャリア芯材中に残留するＣ量の分析は、炭素硫黄同時分析装置（米国ＬＥＣＯ社製）により測定した。
それらの測定結果を表１および図１に示した。ここで、図１は、縦軸に摩擦帯電量を採り、横軸にＣａＣＯ３の添加量を採ったグラフである。
This granulated product was filled in a firing furnace and fired at 1180 ° C. for 4 hours in a nitrogen gas atmosphere to obtain a massive fired product. The obtained fired product is pulverized with a hammer mill, and the pulverized product is applied to an air classifier to classify and remove the fine powder portion. Then, the nonmagnetic portion is separated by magnetic field separation, and further passed through a 70 μm sieve to have an average particle size of 60 μm. A carrier core was obtained.
The carrier core material obtained was triboelectrically charged by placing 19 g of the carrier core material to be measured and 1 g of toner in a 50 cc stoppered test tube, shaking for 20 minutes, and tribocharging of the carrier core material to be measured after shaking. The amount was measured using a blow-off charge measuring device (manufactured by Toshiba Chemical Corporation).
For measuring the static resistance value, 5 g of an insulative pipe having a diameter of 12.9 mmφ was accurately filled with the carrier core material to be measured, and a pressure of 265 g was applied to connect the electrodes to the electrodes installed above and below the pipe. It measured using the super insulation meter (made by Toa Denpa Kogyo Co., Ltd.).
The core apparent density and fluidity were measured according to JIS standards.
The saturation magnetization was measured by a room temperature dedicated vibration sample magnetometer (VSM) (manufactured by Toei Industry Co., Ltd.).
Analysis of the amount of C remaining in the carrier core material was measured with a carbon-sulfur simultaneous analyzer (manufactured by LECO, USA).
The measurement results are shown in Table 1 and FIG. Here, FIG. 1 is a graph in which the amount of triboelectric charge is taken on the vertical axis and the amount of CaCO 3 added is taken on the horizontal axis.
〔実施例２〕
実施例１と同様にしてスラリーを調製した。
このスラリーへ、ＣａＣＯ３及びＣを添加したが、ＣａＣＯ３の添加量は、混合粉に対するＣａの割合がＣａ元素換算で０．６質量％となる量（ＣａＣＯ３の添加量で、１．５質量％）とし、Ｃの添加量は混合粉に対するＣの割合がＣ元素換算で０．６質量％となる量（ＣＢの添加量で、０．６質量％）とした。
これ以降も実施例１と同様にして、キャリア芯材を得た。得られたキャリア芯材の残留するＣ量、摩擦帯電量、コア見掛密度、静抵抗、飽和磁化及び流動度を測定し、その結果を表１および図１に示した。
[Example 2]
A slurry was prepared in the same manner as in Example 1.
CaCO 3 and C were added to this slurry. The amount of CaCO 3 added was such that the Ca ratio to the mixed powder was 0.6% by mass in terms of Ca element (the amount of CaCO 3 added was 1.5%. The amount of C added was such that the ratio of C to the mixed powder was 0.6% by mass in terms of C element (the amount of CB added was 0.6% by mass).
Thereafter, a carrier core material was obtained in the same manner as in Example 1. The residual C amount, triboelectric charge amount, core apparent density, static resistance, saturation magnetization and fluidity of the obtained carrier core material were measured, and the results are shown in Table 1 and FIG.
〔実施例３〕
Ｍｎ原料としてＭｎ３Ｏ４を、またＦｅ原料としてＦｅ２Ｏ３を準備する。そして、焼成後のソフトフェライト組成比として（ＭｎＯ）：（Ｆｅ２Ｏ３）＝４０：６０（モル比）となる割合でこれらの原料を調合し混合粉とした。この混合粉に対して、１．５質量％のポリカルボン酸系分散剤と、水とを加えて、スラリー濃度８４質量％程度のスラリーとした。このスラリーへ、ＣａＣＯ３及びＣを添加した。ＣａＣＯ３の添加量は、混合粉に対するＣａの割合がＣａ元素換算で０．４質量％となる量（ＣａＣＯ３の添加量で、１．０質量％）とし、Ｃの添加量は混合粉に対するＣの割合がＣ元素換算で０．７質量％となる量（ＣＢの添加量で、０．７質量％）とした。
これ以降は実施例１と同様にして、キャリア芯材を得た。得られたキャリア芯材の残留するＣ量、摩擦帯電量、コア見掛密度、静抵抗、飽和磁化及び流動度を測定し、その結果を表１および図１に示した。
Example 3
Mn 3 O 4 is prepared as the Mn raw material, and Fe 2 O 3 is prepared as the Fe raw material. Then, these raw materials were prepared at a ratio of (MnO) :( Fe 2 O 3 ) = 40: 60 (molar ratio) as a soft ferrite composition ratio after firing to obtain a mixed powder. A 1.5% by mass polycarboxylic acid-based dispersant and water were added to the mixed powder to obtain a slurry having a slurry concentration of about 84% by mass. To this slurry, CaCO 3 and C were added. The amount of CaCO 3 added is such that the ratio of Ca to the mixed powder is 0.4% by mass in terms of Ca element (the amount of CaCO 3 added is 1.0% by mass), and the amount of C added is relative to the mixed powder. The amount of C was 0.7% by mass in terms of C element (the amount of CB added was 0.7% by mass).
Thereafter, a carrier core material was obtained in the same manner as in Example 1. The residual C amount, triboelectric charge amount, core apparent density, static resistance, saturation magnetization and fluidity of the obtained carrier core material were measured, and the results are shown in Table 1 and FIG.
〔実施例４〕
実施例３と同様にしてスラリーを調製した。
このスラリーへ、ＣａＣＯ３及びＣを添加したが、ＣａＣＯ３の添加量は、混合粉に対するＣａの割合がＣａ元素換算で０．６質量％となる量（ＣａＣＯ３の添加量で、１．５質量％）とし、Ｃの添加量は混合粉に対するＣの割合がＣ元素換算で０．７質量％となる量（ＣＢの添加量で、０．７質量％）とした。
これ以降は実施例１と同様にして、キャリア芯材を得た。得られたキャリア芯材の残留するＣ量、摩擦帯電量、コア見掛密度、静抵抗、飽和磁化及び流動度を測定し、その結果を表１および図１に示した。
Example 4
A slurry was prepared in the same manner as in Example 3.
CaCO 3 and C were added to this slurry. The amount of CaCO 3 added was such that the Ca ratio to the mixed powder was 0.6% by mass in terms of Ca element (the amount of CaCO 3 added was 1.5%. The amount of C added was such that the ratio of C to the mixed powder was 0.7% by mass in terms of C element (the amount of CB added was 0.7% by mass).
Thereafter, a carrier core material was obtained in the same manner as in Example 1. The residual C amount, triboelectric charge amount, core apparent density, static resistance, saturation magnetization and fluidity of the obtained carrier core material were measured, and the results are shown in Table 1 and FIG.
〔実施例５〕
実施例３と同様にしてスラリーを調製した。
このスラリーへ、ＣａＣＯ３及びＣを添加したが、ＣａＣＯ３の添加量は、混合粉に対するＣａの割合がＣａ元素換算で０．８質量％となる量（ＣａＣＯ３の添加量で、２．０質量％）とし、Ｃの添加量は混合粉に対するＣの割合がＣ元素換算で０．７質量％となる量（ＣＢの添加量で、０．７質量％）とした。
これ以降は実施例１と同様にして、キャリア芯材を得た。得られたキャリア芯材の残留するＣ量、摩擦帯電量、コア見掛密度、静抵抗、飽和磁化及び流動度を測定し、その結果を表１および図１に示した。
Example 5
A slurry was prepared in the same manner as in Example 3.
CaCO 3 and C were added to this slurry, and the amount of CaCO 3 added was such that the ratio of Ca to the mixed powder was 0.8% by mass in terms of Ca element (the amount of CaCO 3 added was 2.0%. The amount of C added was such that the ratio of C to the mixed powder was 0.7% by mass in terms of C element (the amount of CB added was 0.7% by mass).
Thereafter, a carrier core material was obtained in the same manner as in Example 1. The residual C amount, triboelectric charge amount, core apparent density, static resistance, saturation magnetization and fluidity of the obtained carrier core material were measured, and the results are shown in Table 1 and FIG.
〔比較例１〕
ＣａＣＯ３を無添加とした以外は、実施例１と同様にしてキャリア芯材を得た。得られたキャリア芯材の残留するＣ量、摩擦帯電量、コア見掛密度、静抵抗、飽和磁化及び流動度を測定し、その結果を表１および図１に示した。
[Comparative Example 1]
A carrier core material was obtained in the same manner as in Example 1 except that CaCO 3 was not added. The residual C amount, triboelectric charge amount, core apparent density, static resistance, saturation magnetization and fluidity of the obtained carrier core material were measured, and the results are shown in Table 1 and FIG.
〔比較例２〕
ＣａＣＯ３を無添加とした以外は、実施例３と同様にしてキャリア芯材を得た。得られたキャリア芯材の残留するＣ量、摩擦帯電量、コア見掛密度、静抵抗、飽和磁化及び流動度を測定し、その結果を表１および図１に示した。
[Comparative Example 2]
A carrier core material was obtained in the same manner as in Example 3 except that CaCO 3 was not added. The residual C amount, triboelectric charge amount, core apparent density, static resistance, saturation magnetization and fluidity of the obtained carrier core material were measured, and the results are shown in Table 1 and FIG.
Claims (6)
前記ソフトフェライト中に、Ｃａ化合物をＣａ元素換算で０．３〜０．８質量％含有し、１７μＣ／ｇ〜３０μＣ／ｇの摩擦帯電量を有することを特徴とする電子写真現像剤用キャリア芯材。 A carrier core material for an electrophotographic developer using a soft ferrite containing Amol% Fe 2 O 3 and Bmol% MnO (provided that 60 ≦ A ≦ 65, 35 ≦ B ≦ 40, A + B = 100 ) ,
A carrier core for an electrophotographic developer containing 0.3 to 0.8% by mass of a Ca compound in terms of Ca element in the soft ferrite and having a triboelectric charge of 17 μC / g to 30 μC / g Wood.
前記ソフトフェライト中に、Ｃａ化合物をＣａ元素換算で０．３〜０．８質量％含有し、１７μＣ／ｇ〜３０μＣ／ｇの摩擦帯電量を有することを特徴とする電子写真現像剤用キャリア芯材。 A carrier core for an electrophotographic developer containing 0.3 to 0.8% by mass of a Ca compound in terms of Ca element in the soft ferrite and having a triboelectric charge of 17 μC / g to 30 μC / g Wood.
当該電子写真現像剤用キャリア粉の有する摩擦帯電量の値と、前記電子写真現像剤用キャリア芯材の有する摩擦帯電量の値とが、±１０％以内の範囲で一致していることを特徴とする電子写真現像剤用キャリア粉。 A carrier powder for an electrophotographic developer according to claim 3,
The value of the triboelectric charge possessed by the carrier powder for electrophotographic developer and the value of the triboelectric charge possessed by the carrier core material for electrophotographic developer are consistent within a range of ± 10%. A carrier powder for an electrophotographic developer.
４０、Ａ+Ｂ＝１００)となるように調合し、さらに、Ｃａ化合物をＣａ元素換算で０．３〜０．８質量％の添加し、且つ、Ｃ化合物をＣ元素換算で０．５〜１．０質量％添加し混合して、調合原料を得る調合工程と、
調合原料を造粒しペレットを得る造粒工程と、
ペレットを焼成してソフトフェライトを得る焼成工程と、
ソフトフェライトを解砕して篩い分けしキャリア芯材を得る篩分工程とを、有することを特徴とする電子写真現像剤用キャリア芯材の製造方法。 Soft ferrite containing Amol% Fe 2 O 3 and Bmol% MnO as a ferrite composition after firing of iron oxide and Mn compound (provided that 60 ≦ A ≦ 65, 35 ≦ B ≦
40, A + B = 100) , 0.3 to 0.8% by mass of Ca compound in terms of Ca element, and 0.5 to 0.5% in terms of C element. A mixing step of adding 1.0% by mass and mixing to obtain a mixed raw material;
A granulation step of granulating the blended raw material to obtain pellets;
A firing step of firing pellets to obtain soft ferrite;
And a sieving step of pulverizing and sieving soft ferrite to obtain a carrier core material.
前記電子写真現像剤用キャリア粉の有する摩擦帯電量の値と、前記キャリア芯材の有する摩擦帯電量の値とが、±１０％以内の範囲で一致するように、前記Ｃａ化合物の添加量を設定することを特徴とする電子写真現像剤用キャリア粉の製造方法。 A carrier core material for an electrophotographic developer according to claim 5, wherein the carrier powder for an electrophotographic developer is obtained by coating a resin to obtain a carrier powder for an electrophotographic developer,
The amount of addition of the Ca compound is adjusted so that the value of the triboelectric charge possessed by the carrier powder for electrophotographic developer and the value of the triboelectric charge possessed by the carrier core coincide within a range of ± 10%. A method for producing a carrier powder for an electrophotographic developer, characterized by comprising:
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| JP5578842B2 (en) * | 2009-12-14 | 2014-08-27 | Ｄｏｗａエレクトロニクス株式会社 | Method for producing ferrite particles |
| JP2011150098A (en) * | 2010-01-21 | 2011-08-04 | Dowa Electronics Materials Co Ltd | Ferrite particle, carrier for electrophotographic development using the same, and electrophotographic developer |
| JP5822378B2 (en) * | 2011-01-14 | 2015-11-24 | Ｄｏｗａエレクトロニクス株式会社 | Ferrite particles, electrophotographic developer carrier and electrophotographic developer using the same |
| JP5645728B2 (en) * | 2011-03-24 | 2014-12-24 | Ｄｏｗａエレクトロニクス株式会社 | Ferrite particles, electrophotographic carrier and electrophotographic developer using the same |
| CN104603694B (en) * | 2012-08-30 | 2019-07-12 | 同和电子科技有限公司 | Manufacturing method, electrophotographic developing carrier core material, electrophotographic developing carrier and the electrophotographic developing of electrophotographic developing carrier core material |
| WO2014033881A1 (en) * | 2012-08-30 | 2014-03-06 | Ｄｏｗａエレクトロニクス株式会社 | Method for producing carrier core material for electrophotographic developers, carrier core material for electrophotographic developers, carrier for electrophotographic developers, and electrophotographic developer |
| JP5736078B1 (en) * | 2014-05-31 | 2015-06-17 | Ｄｏｗａエレクトロニクス株式会社 | Ferrite particles, electrophotographic carrier and electrophotographic developer using the same |
| JP6503645B2 (en) * | 2014-06-20 | 2019-04-24 | 富士ゼロックス株式会社 | Carrier for electrostatic image development, developer for electrostatic image development, developer cartridge, process cartridge, and image forming apparatus |
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