JP2010112997A - Carrier core material for electrophotographic developer, method for manufacturing the same, carrier for electrophotographic developer and electrophotographic developer - Google Patents
Carrier core material for electrophotographic developer, method for manufacturing the same, carrier for electrophotographic developer and electrophotographic developer Download PDFInfo
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- JP2010112997A JP2010112997A JP2008283086A JP2008283086A JP2010112997A JP 2010112997 A JP2010112997 A JP 2010112997A JP 2008283086 A JP2008283086 A JP 2008283086A JP 2008283086 A JP2008283086 A JP 2008283086A JP 2010112997 A JP2010112997 A JP 2010112997A
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Abstract
Description
本発明は、電子写真現像剤用キャリア芯材およびその製造方法、電子写真現像剤用キャリア、並びに電子写真現像剤に係り、更に詳細には、プリンター等で使用される電子写真現像剤に用いられる電子写真現像剤用キャリア芯材およびその製造方法、電子写真現像剤用キャリア、並びに電子写真現像剤に関する。 The present invention relates to a carrier core material for an electrophotographic developer and a method for producing the same, a carrier for an electrophotographic developer, and an electrophotographic developer. More specifically, the present invention is used for an electrophotographic developer used in a printer or the like. The present invention relates to a carrier core material for an electrophotographic developer and a production method thereof, a carrier for an electrophotographic developer, and an electrophotographic developer.
従来、複写機、プリンター等で使用される電子写真現像方法としては、カスケード法、磁気ブラシ現像法、その他の方法が用いられている。近年は、感光体ドラム上に形成された静電潜像に、磁気ブラシを介してトナー像を顕像化させた後、熱定着させて画像を得る磁気ブラシ現像法が一般的な手段である。さらに最近では、当該磁気ブラシをトナーのみで形成する一成分系現像剤より、トナーを電子写真現像剤用キャリア(本発明において、「キャリア」と記載する場合がある。)の粒子上に電気的に配向させて磁気ブラシを形成する二成分系現像剤が多用されている。 Conventionally, as an electrophotographic developing method used in a copying machine, a printer, etc., a cascade method, a magnetic brush developing method, and other methods are used. In recent years, a general method is a magnetic brush developing method in which an electrostatic latent image formed on a photosensitive drum is visualized with a toner image via a magnetic brush and then thermally fixed to obtain an image. . More recently, the toner is electrically formed on particles of a carrier for an electrophotographic developer (in the present invention, sometimes referred to as “carrier”) than a one-component developer that forms the magnetic brush with toner alone. Two-component developers that are oriented to form a magnetic brush are often used.
二成分系現像剤ではキャリアとして、当該キャリア粒子を構成する芯材(本発明において、「キャリア芯材」と記載する場合がある。)の表面にトナーと逆帯電性の樹脂を適度に被覆させたものが用いられる。キャリアの粒子が、磁気スリーブ上に形成する磁気ブラシは、磁気特性や表面形状により、ブラシチェーンの粒子同士の保持力を変化させることが知られている。画像現像時の条件により、現像スリーブの回転によって得られる遠心力が保持力に勝る結果、磁気ブラシからキャリアが飛散し感光体上に付着する現象(キャリア付着)が発生する。当該感光体上に付着したキャリアは、そのまま転写部に至ることがあるが、当該感光体上にキャリアが付着した状態では、当該キャリア周辺のトナー像が転写紙に転写されない為、画像異常となるものである。 In the two-component developer, as a carrier, the surface of the core material constituting the carrier particles (in the present invention, sometimes referred to as “carrier core material”) is appropriately coated with a toner and a reversely chargeable resin. Is used. It is known that a magnetic brush formed by carrier particles on a magnetic sleeve changes the holding force between the particles of the brush chain depending on the magnetic properties and surface shape. Depending on the conditions during image development, the centrifugal force obtained by the rotation of the developing sleeve is superior to the holding force, and as a result, a phenomenon occurs in which carriers are scattered from the magnetic brush and adhere to the photosensitive member (carrier adhesion). The carrier attached on the photoconductor may reach the transfer portion as it is, but when the carrier is attached on the photoconductor, the toner image around the carrier is not transferred onto the transfer paper, resulting in an image abnormality. Is.
また、市場においては、当該電子写真に関して高画質化、電子写真用現像剤に関しては長寿命化の要求が高まっている。それに伴い、使用されているトナーの粒子は小粒径化され、当該トナーと混合されて用いられているキャリア粒子を小粒径化し、高画質を得ることが試みられている。
しかし、当該小粒径化されたキャリア粒子は、ますます、キャリア付着やキャリア飛散を発生し易いという問題があった。磁気ブラシを形成した小粒径キャリアの粒子間の保持力は、一個一個の粒子の持つ磁力と、粒子同士が結合している部分の面積に比例して強くなるため、小粒径化は保持力を阻害していると推測できる。
In the market, there is a growing demand for higher image quality for electrophotography and longer life for electrophotographic developers. Accompanying this, attempts have been made to reduce the particle size of the toner particles used and to reduce the particle size of the carrier particles used by mixing with the toner to obtain high image quality.
However, the carrier particles having a reduced particle size are more likely to cause carrier adhesion and carrier scattering. The holding force between the particles of the small particle carrier that forms the magnetic brush increases in proportion to the magnetic force of each particle and the area of the part where the particles are bonded to each other. It can be inferred that it is inhibiting the power.
一方、現像機の高速化に伴い、現像機内での撹拌負荷が増加し、撹拌ストレスによる磁性キャリア表面の樹脂の剥離が発生するという問題もある。その結果、キャリア芯材が露出することになり、電荷のリークが生じる。このような電荷のリークは画質劣化の原因の一つであるため、従来の磁性キャリアでは、被覆樹脂の膜厚を厚くすることで樹脂の剥離を防いでいる。
しかし、キャリア芯材と樹脂との間の結合力(接着力)が不十分であると、使用時間が増すにつれて、粒子同士の衝突により、樹脂皮膜の摩耗や破損が起こり、当該皮膜が脱離する。その際、キャリア芯材が表面露出し、帯電性が不均一となることから、画像劣化を引き起こす。
On the other hand, as the speed of the developing machine increases, the stirring load in the developing machine increases, and there is a problem that the resin on the surface of the magnetic carrier is peeled off due to stirring stress. As a result, the carrier core material is exposed, and charge leakage occurs. Since such charge leakage is one of the causes of image quality deterioration, the conventional magnetic carrier prevents the resin from peeling by increasing the thickness of the coating resin.
However, if the bonding force (adhesive strength) between the carrier core material and the resin is insufficient, as the usage time increases, the resin film wears and breaks due to collisions between the particles, and the film is detached. To do. At that time, the surface of the carrier core material is exposed and the chargeability becomes non-uniform, which causes image deterioration.
ここで、例えば特許文献1は、キャリア芯材にAl2O3を1〜50質量%の範囲内で意図的に添加させ、樹脂の耐久性を向上させることを提案している。
しかしながら、特許文献1に記載の技術では、多量のAl2O3の存在による磁気特性の低下と、当該磁気特性の低下に伴う現像画質の劣化が懸念される。 However, in the technique described in Patent Document 1, there is a concern that the magnetic characteristics are deteriorated due to the presence of a large amount of Al 2 O 3 and the development image quality is deteriorated due to the deterioration of the magnetic characteristics.
また、現像剤の中で、摩耗によって生じるコート樹脂の剥離やキャリア粒子割れ等によるキャリア付着やキャリア飛散を抑制するためには、キャリア粉の表面の形状が重要であることは知られているが、表面形状を制御することは困難であった。 In addition, in the developer, it is known that the shape of the surface of the carrier powder is important in order to suppress carrier adhesion and carrier scattering due to peeling of the coat resin caused by abrasion and carrier particle cracking. It was difficult to control the surface shape.
本発明の目的は、その目的とするところは、画像異常の原因であるキャリア飛散を抑制し、且つコート芯材に被覆される樹脂の剥離を防止する効果の高いキャリア芯材およびその製造方法、キャリア、並びに、電子写真現像剤を提供することにある。 The object of the present invention is to provide a carrier core material having a high effect of suppressing carrier scattering that is a cause of image abnormality and preventing peeling of the resin coated on the coat core material, and a method for producing the same, It is to provide a carrier and an electrophotographic developer.
本発明者らが、上記課題を解決すべく鋭意検討を重ねた結果、従来技術において省みられることのなかった濃度で分散させ、キャリア粉となるスラリーを作る際に添加するAl2O3粒子の平均粒径を、0.5μm以下とすることによって表面の形状を制御することを見出し、本発明を完成するに至った。 As a result of intensive investigations by the present inventors to solve the above-mentioned problems, Al 2 O 3 particles added when making a slurry to be a carrier powder dispersed at a concentration that has not been omitted in the prior art It was found that the shape of the surface is controlled by setting the average particle size to 0.5 μm or less, and the present invention has been completed.
即ち、上記課題を解決するための手段は、
Fe3O4で表記されるマグネタイト、または、一般式(MxFe3−x)O4(但し、Mは、Mg、Mn、Ca、Ti、Cu、Zn、Sr、Niからなる群より選ばれる少なくとも1種以上の金属粉末、0<x<3)で表記されるソフトフェライトを有し、
当該マグネタイトまたはソフトフェライト中に0.1質量%以上、1質量%以下のAlが含有され、平均表面粗さが0.1μm以上、0.5μm以下であ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 means for solving the above problems are as follows:
Magnetite represented by Fe 3 O 4 or general formula (M x Fe 3-x ) O 4 (where M is selected from the group consisting of Mg, Mn, Ca, Ti, Cu, Zn, Sr, Ni) Having at least one kind of metal powder, soft ferrite represented by 0 <x <3),
For an electrophotographic developer, wherein the magnetite or soft ferrite contains 0.1% by mass or more and 1% by mass or less of Al and has an average surface roughness of 0.1 μm or more and 0.5 μm or less. It is a carrier core material.
また、媒体液中へ、平均粒径が0.5μm以下のAl2O3粒子を粉末状態またはコロイド状態で分散させる工程と
前記Al2O3粒子を分散させた媒体液中へ、Fe粉末と、金属粉末とを分散させ、攪拌することによってスラリーを得る工程を備えた製造方法である。
Further, a step of dispersing Al 2 O 3 particles having an average particle size of 0.5 μm or less in a medium solution in a powder state or a colloid state; and a Fe powder in a medium solution in which the Al 2 O 3 particles are dispersed , A manufacturing method including a step of obtaining a slurry by dispersing metal powder and stirring.
この電子写真現像剤用キャリア芯材の製造方法において、前記金属粉末が、Fe、Mg、Mn、Ca、Ti、Cu、Zn、Sr、Niからなる群より選ばれた少なくとも1種以上の金属粉末である。 In this method for producing a carrier core material for an electrophotographic developer, the metal powder is at least one metal powder selected from the group consisting of Fe, Mg, Mn, Ca, Ti, Cu, Zn, Sr, and Ni. It is.
本発明によれば、キャリア芯材中にAl2O3粒子を、従来技術において省みられることのなかった濃度で分散させ、キャリア粉となるスラリーを作る際に添加するAl2O3粒子の平均粒径を、0.5μm以下とすることによって表面の形状を制御することとしたため、画像異常の原因であるキャリア飛散を抑制し、且つコート芯材に被覆される樹脂の剥離を防止する効果の高いキャリア芯材およびその製造方法、キャリア、並びに、電子写真現像剤を提供できる。 According to the present invention, Al 2 O 3 particles are dispersed in a carrier core material at a concentration that has not been omitted in the prior art, and the Al 2 O 3 particles added when making a slurry to be a carrier powder. Since the surface shape is controlled by setting the average particle size to 0.5 μm or less, the effect of suppressing carrier scattering that is a cause of image abnormality and preventing the resin coated on the coat core material from being peeled off. High carrier core material and method for producing the same, carrier, and electrophotographic developer can be provided.
以下、本発明について、1.キャリア芯材、2.キャリア、3.キャリア芯材およびキャリアの製造方法、4.電子写真現像剤、の順で説明する。
なお、本特許請求の範囲及び本明細書において、「%」は特記しない限り質量百分率を表すものとする。
Hereinafter, the present invention is as follows. Carrier core material, 2. Carrier, 3. 3. Carrier core material and carrier manufacturing method; The electrophotographic developer will be described in this order.
In the claims and the specification, “%” represents a mass percentage unless otherwise specified.
1.キャリア芯材
上述の如く、本発明に係るキャリア芯材は、Fe3O4で表記されるマグネタイト、または、一般式(MxFe3−x)O4(但し、Mは、Mg、Mn、Ca、Ti、Cu、Zn、Sr、Niからなる群より選ばれる少なくとも1種以上の金属粉末、0<x<3)で表記されるソフトフェライトを有しており、当該マグネタイトまたはソフトフェライト中には平均粒径0.5μm以下のAl2O3粒子が固溶している。即ち、当該マグネタイトまたはソフトフェライト中には、当該平均粒径0.5μm以下のAl2O3粒子の添加することによりAlが固溶し、0.1質量%以上、1質量%以下のAlが含有している。具体的には、キャリア芯材がマグネタイトである場合、逆スピネル構造を持つ格子結晶中のFe原子をAl原子が置換して、FexAl3−xO4の置換型固溶体を形成している。
1. Carrier Core Material As described above, the carrier core material according to the present invention is a magnetite represented by Fe 3 O 4 or a general formula (M x Fe 3-x ) O 4 (where M is Mg, Mn, At least one metal powder selected from the group consisting of Ca, Ti, Cu, Zn, Sr, and Ni, and having soft ferrite represented by 0 <x <3), and in the magnetite or soft ferrite Is a solid solution of Al 2 O 3 particles having an average particle size of 0.5 μm or less. That is, in the magnetite or soft ferrite, Al is dissolved by adding Al 2 O 3 particles having an average particle size of 0.5 μm or less, and 0.1 mass% or more and 1 mass% or less of Al is contained. Contains. Specifically, when the carrier core material is magnetite, the Fe atom in the lattice crystal having an inverse spinel structure is substituted with an Al atom to form a substitutional solid solution of Fe x Al 3-x O 4 . .
[キャリア芯材を構成する粒子の表面性]
本発明者らの検討によれば、キャリア芯材への非磁性成分の添加(存在)の有無、添加粒径、および添加量により、当該キャリア芯材を構成する粒子表面の凹凸の度合いやグレイン(表面に見られる凹状の筋に囲まれた隆起した凸部分)の成長性に大きな差異が見られることがわかった。
具体的には、平均粒径0.5μm以下のAl2O3粒子を添加したキャリア芯材では、グレインが表面より外側に向けて成長しにくく、凹凸性が小さくなる方向にある。また、係るキャリア芯材では、BET値で、0.1m2/g〜0.2m2/g、平均表面粗さが、0.1μm以上、0.5μm以下、好ましくは0.1μm以上、0.4μm以下の範囲の表面性を有する。
[Surface properties of particles constituting the carrier core]
According to the study by the present inventors, the degree of unevenness on the surface of the particles constituting the carrier core material and the grain are determined by the presence or absence of addition (presence) of the nonmagnetic component to the carrier core material, the added particle size, and the addition amount. It was found that there is a large difference in the growth of (a raised convex part surrounded by concave stripes seen on the surface).
Specifically, in the carrier core material to which Al 2 O 3 particles having an average particle size of 0.5 μm or less are added, the grains are unlikely to grow outward from the surface, and the unevenness tends to be reduced. Further, in the carrier core material according, the BET value, 0.1m 2 /g~0.2m 2 / g, an average surface roughness, 0.1 [mu] m or more, 0.5 [mu] m or less, preferably 0.1 [mu] m or more, 0 .Surface properties in the range of 4 μm or less.
このように、キャリア芯材へ0.5μm以下のAl2O3粒子を添加することで、BET値および表面粗さの小さいキャリア芯材を得ることが出来る。そして、キャリア芯材のBET値および表面粗さを小さくすることにより、キャリア飛散が抑制される。これは、キャリア芯材のBET値および表面粗さを小さくすることで、現像器内の攪拌において、粒子同士の割れや摩耗、また樹脂コートのはがれを減少させることができる。現像剤の中で、摩耗によって生じるコート樹脂の剥離やキャリア粒子割れといった問題を解消できるためと考えられる。 Thus, a carrier core material having a small BET value and surface roughness can be obtained by adding Al 2 O 3 particles of 0.5 μm or less to the carrier core material. And carrier scattering is suppressed by making BET value and surface roughness of a carrier core material small. By reducing the BET value and the surface roughness of the carrier core material, it is possible to reduce cracking and abrasion between particles and peeling of the resin coat during stirring in the developing device. This is considered to be because the problems such as peeling of the coat resin and carrier particle cracking caused by abrasion can be solved in the developer.
[キャリア芯材の組成]
本発明に係るキャリア芯材を構成する磁性成分物質は、対象となる電子写真現像装置の特性に合った磁気特性を有する物質を選択すればよい。例えば、画像特性を考慮した場合、マグネタイトであるFe3O4や、ソフトフェライトであるMnxFe3−xO4等が好適に用いられる。これらの磁性物質は、十分高い磁化と低い残留磁化をもつためである。
一方、本発明のキャリア芯材では、上述のように、表面性を変化させるため非磁性成分を存在させる。なお、キャリアの磁気特性は、当該非磁性成分の存在比率に応じて低下するが、表面性と、キャリア芯材に必要とされる磁力や抵抗値とのバランスを考慮し、非磁性成分であるAl2O3粒子の粒径、添加量を調整することで、非常に再現性良くキャリアの特性を調整できる。
[Composition of carrier core material]
As the magnetic component substance constituting the carrier core material according to the present invention, a substance having a magnetic property suitable for the characteristics of the target electrophotographic developing apparatus may be selected. For example, in consideration of image characteristics, magnetite Fe 3 O 4 , soft ferrite Mn x Fe 3-x O 4 and the like are preferably used. This is because these magnetic materials have sufficiently high magnetization and low remanent magnetization.
On the other hand, in the carrier core material of the present invention, as described above, a nonmagnetic component is present in order to change the surface property. Note that the magnetic properties of the carrier are reduced according to the abundance ratio of the non-magnetic component, but it is a non-magnetic component in consideration of the balance between the surface property and the magnetic force and resistance value required for the carrier core material. By adjusting the particle diameter and addition amount of the Al 2 O 3 particles, the carrier characteristics can be adjusted with very good reproducibility.
具体的には、Al2O3粒子の場合は、例えば、キャリア芯材のメイン原料のFe2O3とフェライトを合成するその他の金属酸化物の総量に対して、当該Al2O3粒子に由来するAl量が0.1質量%以上、1質量%以下となるよう原料混合時に添加すれば良い。当該Al量が0.1質量%以上であればキャリア芯材を構成するグレインの凹凸を確保でき、また1質量%以下であれば、キャリア形状が球状を大きく外れることがなく、現像機内での流動性を保ち、且つ、実用上必要な磁力を維持できる。更に望ましくは0.3質量%以上、1質量%以下の割合で添加するのがよい。Al2O3粒子を添加する形態は、粉末状であっても、コロイド溶液状であっても良い。 Specifically, in the case of Al 2 O 3 particles, for example, the total amount of other metal oxides that synthesize ferrite with Fe 2 O 3 as the main raw material of the carrier core material is the Al 2 O 3 particles. What is necessary is just to add at the time of raw material mixing so that the Al amount derived may be 0.1 mass% or more and 1 mass% or less. If the Al amount is 0.1% by mass or more, the grain irregularities constituting the carrier core material can be secured. If the Al amount is 1% by mass or less, the carrier shape does not greatly deviate from the spherical shape. The fluidity can be maintained and the magnetic force necessary for practical use can be maintained. More preferably, it is added at a ratio of 0.3% by mass or more and 1% by mass or less. The form in which the Al 2 O 3 particles are added may be powder or colloidal solution.
[粒径]
本発明の電子写真現像剤用キャリア芯材の粒度分布は、平均粒径が15μm以上、80μm以下であることが好ましい。平均粒径が15μm以上であればキャリア粒子ひとつひとつの磁化が確保され、キャリア付着現象が効果的に抑制できる。20μm以上であることがより効果的である。また80μm以下であれば比表面積の低下によるトナーの飛散を防ぐことができ、鮮鋭な画質を得る上で有利となる。
そのため、この範囲内にあると、画像特性が良好で、且つ、キャリア飛散が抑制出来き、上記の粒度分布となるよう、製造工程中あるいは工程後に篩などにより分級処理を行うことが好ましい。
[Particle size]
The particle size distribution of the carrier core material for an electrophotographic developer of the present invention preferably has an average particle size of 15 μm or more and 80 μm or less. If the average particle diameter is 15 μm or more, the magnetization of each carrier particle is secured, and the carrier adhesion phenomenon can be effectively suppressed. It is more effective that it is 20 μm or more. On the other hand, if it is 80 μm or less, scattering of toner due to a decrease in specific surface area can be prevented, which is advantageous in obtaining sharp image quality.
For this reason, it is preferable to perform classification treatment with a sieve or the like during or after the production process so that the image characteristics are good and carrier scattering can be suppressed and the above particle size distribution is obtained when it is within this range.
2.キャリア
本発明の電子写真現像剤用樹脂被覆キャリアは、上述の電子写真現像剤用キャリア芯材に、必要な帯電性に応じた熱硬化性樹脂類またはこれらの任意の組合せに係る樹脂を被覆してなる。
このような構成をとることにより、非磁性酸化物を添加しないキャリアと比較して、キャリア飛散が抑制され、破砕特性が大幅に改善される。樹脂被覆後のキャリアの破砕試験強度が良好になるのは、キャリア粒子の表面凹凸部と樹脂被覆面の接触面積に応じて、結合力が上がり、剥離を抑制できるからである。
2. Carrier The resin-coated carrier for an electrophotographic developer of the present invention is obtained by coating the above-described carrier core material for an electrophotographic developer with a thermosetting resin according to a required chargeability or a resin according to any combination thereof. It becomes.
By adopting such a configuration, carrier scattering is suppressed and the crushing characteristics are greatly improved as compared with a carrier to which a nonmagnetic oxide is not added. The reason why the crushing test strength of the carrier after the resin coating is good is that the bonding force increases according to the contact area between the surface irregularities of the carrier particles and the resin coating surface, and peeling can be suppressed.
3.キャリア芯材・キャリアの製造方法
本発明に係るキャリア芯材の製造においては、磁性粉となる原料の他にAl2O3粒子等の非磁性成分を併せて用いる。その際、非磁性成分の粒径が大きいと、粒子内で均一な分散性が悪くなったり、グレインの成長が不均一になったりすることがある。このため、非磁性成分は、5μm以下であることが好ましい。
3. Carrier Core Material / Carrier Production Method In the production of the carrier core material according to the present invention, nonmagnetic components such as Al 2 O 3 particles are used in addition to the raw material to be magnetic powder. At this time, if the particle size of the nonmagnetic component is large, uniform dispersibility in the particles may be deteriorated, and grain growth may be uneven. For this reason, it is preferable that a nonmagnetic component is 5 micrometers or less.
[原料]
Fe3O4で表記されるマグネタイト、または、一般式(MxFe3−x)O4(但し、Mは、Mg、Mn、Ca、Ti、Cu、Zn、Sr又はNi、又はこれらの任意に組合せたもの、0<x<3)で表記されるソフトフェライトのFe供給源としては、Fe2O3が好適に使用できる。Mの原料としては、Fe、Mg、Mn、Ca、Ti、Cu、Zn、Sr又はNi、及びこれら2価の金属を任意に組み合わせたものが好適に使用できる。例えば、MnであればMnCO3、Mn3O4等が使用でき、MgであればMgO、Mg(OH)2、MgCO3が好適に使用できる。そして、これらの原料の配合比を、当該マグネタイトまたはソフトフェライトの目的組成と一致させて秤量し混合して、金属原料混合物を得ることができる。
[material]
Magnetite represented by Fe 3 O 4 , or general formula (M x Fe 3-x ) O 4 (where M is Mg, Mn, Ca, Ti, Cu, Zn, Sr or Ni, or any of these) As an Fe supply source of soft ferrite represented by 0 <x <3), Fe 2 O 3 can be preferably used. As a raw material of M, Fe, Mg, Mn, Ca, Ti, Cu, Zn, Sr or Ni, and any combination of these divalent metals can be suitably used. For example, Mn can be MnCO 3 , Mn 3 O 4 or the like, and Mg can be suitably used MgO, Mg (OH) 2 , or MgCO 3 . Then, the mixing ratio of these raw materials is matched with the target composition of the magnetite or soft ferrite and weighed and mixed to obtain a metal raw material mixture.
原料に配合するAl(アルミニウム)の形態としては、酸化物であるAl2O3粒子が好適に使用される。Al2O3粒子は、粉体状であっても、粒子を水分中に均一分散させたコロイド状液であっても良い。Al2O3粒子の粒径は、平均粒径(D50)で0.5μm以下であれば、キャリア芯材を構成するグレインの凹凸を小さくしやすい。好ましくは、平均粒径(D50)で0.3μm以下である。 As the form of Al (aluminum) to be blended in the raw material, Al 2 O 3 particles that are oxides are preferably used. The Al 2 O 3 particles may be in the form of powder or a colloidal liquid in which the particles are uniformly dispersed in moisture. If the average particle diameter (D50) of the Al 2 O 3 particles is 0.5 μm or less, it is easy to reduce the grain unevenness constituting the carrier core material. Preferably, the average particle size (D50) is 0.3 μm or less.
媒体液は、水にバインダー、分散剤等を添加したものを用意する。バインダーとしては、例えばポリビニルアルコールが好適に使用でき、その媒体液中濃度は0.5〜2質量%程度とすればよい。分散剤としては、例えばポリカルボン酸アンモニウム系のものが好適に使用でき、その媒体液中濃度も0.5〜2質量%程度とすればよい。その他、潤滑剤や、焼結促進剤として、リンやホウ酸等を添加することができる。混合攪拌して得られたスラリーに対し、さらに湿式粉砕を施すことが好ましい。
必要に応じて、原料混合物へ乾式で粉砕処理を加えてもよい。原料粉と媒体液の混合比は、スラリーの固形分濃度が50〜90質量%になるようにすることが望ましい。
The medium liquid is prepared by adding a binder, a dispersant and the like to water. As the binder, for example, polyvinyl alcohol can be suitably used, and the concentration in the medium liquid may be about 0.5 to 2% by mass. As the dispersant, for example, an ammonium polycarboxylate-based one can be preferably used, and the concentration in the medium liquid may be about 0.5 to 2% by mass. In addition, phosphorus, boric acid, or the like can be added as a lubricant or a sintering accelerator. It is preferable to further wet-grind the slurry obtained by mixing and stirring.
If necessary, the raw material mixture may be subjected to a pulverization treatment in a dry manner. The mixing ratio of the raw material powder and the medium liquid is preferably set so that the solid content concentration of the slurry is 50 to 90% by mass.
また、上記の媒体液中へ、Fe原料、M原料の添加前に、Al2O3粒子を先に分散させることが好ましい。Al2O3粒子の添加量は、上述したように、Al換算で0.1質量%以上、1質量%以下とする。
当該Al2O3粒子の添加量が、Fe原料、M原料の量に対し非常に微量であるため、先に媒体液中に分散させることで、均一な分散状態を得られる。また、湿式粉砕等の処理を行ったりすることで、Al2O3粒子の分散性を上げてもよい。
Moreover, it is preferable to disperse Al 2 O 3 particles first in the medium solution before adding the Fe raw material and the M raw material. As described above, the addition amount of the Al 2 O 3 particles is 0.1% by mass or more and 1% by mass or less in terms of Al.
Since the addition amount of the Al 2 O 3 particles is very small with respect to the amounts of the Fe raw material and the M raw material, a uniform dispersion state can be obtained by first dispersing in the medium liquid. In addition, by or performs processing such as wet milling, it may be increased dispersibility of the Al 2 O 3 particles.
〔造粒〕
造粒は、上記スラリーを噴霧乾燥機に導入することによって好適に実施できる。噴霧乾燥時の雰囲気温度は100〜300℃程度とすればよい。これにより、概ね、粒子径が10〜200μmの造粒粉を得ることができる(造粒工程)。得られた造粒粉は製品最終粒径を考慮し、振動ふるい等を用いて、粗大粒子や微粉を除去することにより粒度調整することが望ましい。
[Granulation]
Granulation can be suitably carried out by introducing the slurry into a spray dryer. The atmospheric temperature during spray drying may be about 100 to 300 ° C. Thereby, the granulated powder whose particle diameter is 10-200 micrometers can be obtained in general (granulation process). It is desirable to adjust the particle size of the resulting granulated powder by removing coarse particles and fine powder using a vibration sieve or the like in consideration of the final particle size of the product.
〔焼成〕
次に、造粒粉を700〜1500℃程度に加熱した炉に投入して、マグネタイトまたはソフトフェライトを合成するための一般的な手法で焼成することにより、フェライトを生成させる(焼成工程)。焼成温度が700℃以上であれば、焼結がある程度進み、形状を維持でき、また、生成したフェライトの磁気特性が保たれるので、キャリア飛散が抑制される。1500℃超であると、粒子同士の過剰焼結が起こらず、異形粒子が生じることがない。当該観点からは、700〜1500℃程度で焼成することが好ましい。焼成温度の制御により、キャリア芯材へ所望のBET比表面積を付与することができる。具体的には、焼成温度を上げることでBET比表面積の値は低下し、焼成温度を下げることでBET比表面積の値を増加させることができる。
また、焼成雰囲気は、焼成品の磁力、電気抵抗等のキャリア粉体特性に関わっている。特に磁力は、フェライトの種類によって、大きく影響を受けるため、焼成炉内の酸素濃度を1%以下の還元性の強い雰囲気とすることが望ましい。
[Baking]
Next, the granulated powder is put into a furnace heated to about 700 to 1500 ° C. and fired by a general technique for synthesizing magnetite or soft ferrite, thereby generating ferrite (firing step). If the firing temperature is 700 ° C. or higher, sintering proceeds to some extent, the shape can be maintained, and the magnetic properties of the generated ferrite are maintained, so that carrier scattering is suppressed. When the temperature is higher than 1500 ° C., excessive sintering between particles does not occur, and irregularly shaped particles do not occur. From this point of view, it is preferable to fire at about 700 to 1500 ° C. By controlling the firing temperature, a desired BET specific surface area can be imparted to the carrier core material. Specifically, the value of the BET specific surface area is decreased by raising the firing temperature, and the value of the BET specific surface area can be increased by lowering the firing temperature.
In addition, the firing atmosphere is related to carrier powder characteristics such as magnetic force and electrical resistance of the fired product. In particular, since the magnetic force is greatly affected by the type of ferrite, it is desirable that the oxygen concentration in the firing furnace be a highly reducing atmosphere with a concentration of 1% or less.
得られた焼成物は、この段階で粒度調整することが望ましい。例えば、焼成物をハンマーミル等で粗解粒し、次に気流分級機で1次分級し、さらに、振動ふるいまたは超音波ふるいで粒度を揃える処理を行うことにより、粒度調整された焼成物を得ることができる。当該粒度調整後、さらに磁場選鉱機にかけ、非磁性粒子を除去することが望ましい。 It is desirable to adjust the particle size of the obtained fired product at this stage. For example, the baked product is roughly pulverized with a hammer mill, etc., then subjected to primary classification with an airflow classifier, and further subjected to a process of aligning the particle size with a vibration sieve or an ultrasonic sieve to obtain a baked product with adjusted particle size. Obtainable. After adjusting the particle size, it is desirable to remove the non-magnetic particles by applying a magnetic field separator.
〔高抵抗化処理〕
上記焼成物を酸化性雰囲気中にて加熱することにより、高抵抗層を形成し、高抵抗化してもよい(高抵抗化処理工程)。加熱雰囲気は、大気、または、酸素と窒素の混合雰囲気とすればよい。加熱温度は200〜800℃、好ましくは250〜600℃とし、処理時間は30分〜5時間程度とすればよい。
このようにして本発明に係るキャリア芯材を得ることが出来る。
[High resistance treatment]
By heating the fired product in an oxidizing atmosphere, a high resistance layer may be formed and the resistance may be increased (high resistance treatment step). The heating atmosphere may be air or a mixed atmosphere of oxygen and nitrogen. The heating temperature is 200 to 800 ° C., preferably 250 to 600 ° C., and the treatment time is about 30 minutes to 5 hours.
Thus, the carrier core material according to the present invention can be obtained.
〔キャリアの製造〕
得られたキャリア芯材に、樹脂被覆を施す。被覆の方式としては乾式法、流動床、浸漬法等により被覆することができる。より好ましくはキャリア内部に樹脂を充填することから浸漬法や乾式法がより好ましい。ここでは浸漬法を例に挙げ説明する。被覆樹脂としては、シリコーン系樹脂やアクリル樹脂が好ましい。被覆樹脂を溶剤(トルエン等)に20〜40質量%程度溶解させ、樹脂溶液を調製する。被覆操作は、キャリア芯材に対して固形分で0.7〜10%の範囲となるように容器中で混合した後、150〜250℃にて加熱撹拌することにより実施できる。上記の樹脂溶液の濃度、および、樹脂溶液とキャリア芯材との混合比によって、樹脂の被覆量をコントロールすることができる。被覆後に、さらに加熱処理を施して樹脂被覆層を硬化させることによって、本発明に係る電子写真現像剤用キャリアが得られる。
[Manufacture of carriers]
The obtained carrier core material is coated with a resin. As a coating method, coating can be performed by a dry method, a fluidized bed, a dipping method, or the like. More preferably, a dipping method or a dry method is more preferable because the inside of the carrier is filled with a resin. Here, the dipping method will be described as an example. As the coating resin, a silicone resin or an acrylic resin is preferable. About 20 to 40% by mass of the coating resin is dissolved in a solvent (toluene or the like) to prepare a resin solution. The coating operation can be carried out by heating and stirring at 150 to 250 ° C. after mixing in a container so that the solid content is 0.7 to 10% of the carrier core material. The coating amount of the resin can be controlled by the concentration of the resin solution and the mixing ratio of the resin solution and the carrier core material. After the coating, the carrier for an electrophotographic developer according to the present invention is obtained by further heating to cure the resin coating layer.
4.電子写真現像剤
得られた本発明に係るキャリアを、適切な粒径を有するトナーと混合することによって、電子写真現像剤を得ることができる。
4). Electrophotographic Developer An electrophotographic developer can be obtained by mixing the obtained carrier according to the present invention with a toner having an appropriate particle size.
以下に、本発明に係る電子写真用現像剤キャリア芯材の製造方法について、実施例を参照しながら具体的に説明する。
本発明の実施例を示すにあたり、まず、各物性値の測定方法について記述する。
The method for producing an electrophotographic developer carrier core material according to the present invention will be specifically described below with reference to examples.
In showing examples of the present invention, first, a method of measuring each physical property value will be described.
<平均表面粗さ測定>
本発明では、レーザー顕微鏡(オリンパス社製、OLS30−LSU)を用い、粒子表面をスキャンすることで溝深さ、および、平均表面粗さの値を算出した。
粒子表面に存在する溝深さは、キャリア芯材の粒子において10μm四方の範囲を設定し、当該範囲において高さ測定および深さ測定を行って平均線を求め、当該平均線より最も深い位置の深さを溝深さとした。
平均表面粗さは、キャリア芯材の粒子において10μm四方の範囲を設定し、当該範囲において高さ測定を行って平均線を求め、この範囲での平均線から測定曲線までの偏差の絶対値を合成し、平均化することで算出した。
<Average surface roughness measurement>
In this invention, the value of groove depth and average surface roughness was computed by scanning the particle | grain surface using a laser microscope (the Olympus company make, OLS30-LSU).
The groove depth existing on the particle surface is set to a range of 10 μm square in the particle of the carrier core material, and the average line is obtained by performing height measurement and depth measurement within the range, and the groove at the deepest position from the average line The depth was the groove depth.
The average surface roughness is set in a 10 μm square range in the carrier core particles, and the height is measured in the range to obtain an average line, and the absolute value of the deviation from the average line in this range to the measurement curve is calculated. It was calculated by synthesizing and averaging.
<比表面積>
キャリア芯材の比表面積(BET)は、JISZ8830−2001に基づいて測定を行った。
<Specific surface area>
The specific surface area (BET) of the carrier core material was measured based on JISZ8830-2001.
<粒度分布>
キャリア芯材の粒度分布は、マイクロトラック(日機装株式会社製、Model:9320−X100)を用いて測定した。得られた粒度分布より、体積率50%までの積算粒径(本発明においてD50と記載する場合がある。)を算出した。尚、本発明においては、当該D50の値を芯材の平均粒径として記述した。
<Particle size distribution>
The particle size distribution of the carrier core material was measured using a microtrack (manufactured by Nikkiso Co., Ltd., Model: 9320-X100). From the obtained particle size distribution, an integrated particle size up to a volume ratio of 50% (may be referred to as D50 in the present invention) was calculated. In the present invention, the value of D50 is described as the average particle diameter of the core material.
<磁気特性>
キャリア芯材の磁気特性は、VSM(東英工業株式会社製、VSM−P7)を用いて磁化の測定を行い、外部磁場1000Oeにおける磁化σ1000(emu/g)を得た。
<Magnetic properties>
The magnetic properties of the carrier core material were measured using a VSM (manufactured by Toei Kogyo Co., Ltd., VSM-P7) to obtain a magnetization σ 1000 (emu / g) in an external magnetic field of 1000 Oe.
<キャリア飛散の評価試験>
キャリア芯材のキャリア飛散は、直径50mm、表面磁力1000Gaussの磁気ドラムに実施例および比較例で得られたキャリア芯材を充填し、270rpmで30分間回転させた後、飛散した粒子を回収し、その重量を測定することで行った。尚、キャリア飛散量は、比較例1に係るキャリア飛散量を「1」と規格化しており、この値が大きいほどキャリア飛散量が多いことを示している。
当該評価試験結果を表1に示す。
<Evaluation test of carrier scattering>
Carrier scattering of the carrier core material is filled with the carrier core material obtained in the examples and comparative examples in a magnetic drum having a diameter of 50 mm and a surface magnetic force of 1000 Gauss, rotated at 270 rpm for 30 minutes, and then the scattered particles are collected. This was done by measuring the weight. The carrier scattering amount standardizes the carrier scattering amount according to Comparative Example 1 as “1”, and the larger this value, the larger the carrier scattering amount.
The evaluation test results are shown in Table 1.
<画像評価試験>
さらに、各実施例および比較例にかかる磁性キャリアと、粒径1μm程度の市販トナーとを混合して電子写真現像剤を作成し、該電子写真現像剤を用いて画像評価試験を行った。その結果を表2に記載する。尚、評価において、◎は非常に良好なレベル、○は良好なレベル、△は使用可能なレベル、×は使用不可なレベルとした。
<Image evaluation test>
Further, an electrophotographic developer was prepared by mixing the magnetic carrier according to each of Examples and Comparative Examples and a commercially available toner having a particle diameter of about 1 μm, and an image evaluation test was performed using the electrophotographic developer. The results are listed in Table 2. In the evaluation, ◎ is a very good level, ◯ is a good level, Δ is a usable level, and x is a non-usable level.
以下、実施例に基づいて本発明をより具体的に説明するが、本発明はこれらの実施例に限定されるものではない。 EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not limited to these Examples.
〔実施例1〕
原料として、平均粒径D50が0.289μmに微粉砕されたAl2O3粒子粉、Fe2O3粉を用意した。Al2O3粒子粉は、Fe2O3粉量に対して、Al換算で、1質量%となるように秤量した。
一方、水に、分散剤としてポリカルボン酸アンモニウム系分散材を1.0質量%、添加した液(媒体液)を準備した。この媒体液にAl2O3粒子粉を投入し、十分に分散した後、前記秤量されたFe2O3原料粉を投入して、攪拌することにより、これら投入した物質の濃度が76質量%のスラリーを得た。スラリーの分散は、40℃程度の温度をかけながら行ってもよく、また、湿式ボールミル等の装置を用いて湿式粉砕を行ってもよい。
このスラリーを湿式ボールミルにて湿式粉砕し、しばらく攪拌した後、スプレードライヤーにて該スラリーを約125℃の熱風中に噴霧し、粒径10〜200μmの乾燥造粒物を得た。
この造粒物から、網目45μmの篩網を用いて粗粒を分離し、網目25μmの篩網を用いて微粒を分離した後、窒素雰囲気下1000℃で5時間焼成し、フェライト化させた。このフェライト化した焼成物をハンマーミルで解粒し、風力分級機を用いて微粉を除去し、網目45μmの振動ふるいで粗粒を分離し粒度調整した。
45μm以下に粒度調整された焼成物を、350℃の大気下で3時間保持することにより高抵抗化処理を施し、実施例1に係るキャリア芯材を得た。
[Example 1]
As raw materials, Al 2 O 3 particle powder and Fe 2 O 3 powder finely pulverized to an average particle diameter D50 of 0.289 μm were prepared. The Al 2 O 3 particle powder was weighed so as to be 1% by mass in terms of Al with respect to the amount of Fe 2 O 3 powder.
On the other hand, a liquid (medium liquid) prepared by adding 1.0% by mass of an ammonium polycarboxylate dispersant as a dispersant to water was prepared. After the Al 2 O 3 particle powder is charged into this medium liquid and sufficiently dispersed, the above-mentioned weighed Fe 2 O 3 raw material powder is charged and stirred, so that the concentration of these charged substances is 76% by mass. A slurry of was obtained. Dispersion of the slurry may be performed while applying a temperature of about 40 ° C., or wet pulverization may be performed using an apparatus such as a wet ball mill.
The slurry was wet pulverized with a wet ball mill, stirred for a while, and then sprayed into hot air at about 125 ° C. with a spray dryer to obtain a dry granulated product having a particle size of 10 to 200 μm.
From this granulated product, coarse particles were separated using a sieve mesh with a mesh size of 45 μm, fine particles were separated using a sieve mesh with a mesh size of 25 μm, and then fired at 1000 ° C. for 5 hours in a nitrogen atmosphere to be ferritized. The ferritized fired product was pulverized with a hammer mill, fine powder was removed using an air classifier, and coarse particles were separated with a mesh sieve of 45 μm to adjust the particle size.
The fired product whose particle size was adjusted to 45 μm or less was subjected to a high resistance treatment by holding in an atmosphere of 350 ° C. for 3 hours to obtain a carrier core material according to Example 1.
〔実施例2〕
添加するAl2O3粒子粉は平均粒径D50が0.239μmのものをFe2O3粉量に対して、Al換算で、0.5質量%となるように秤量し、実施例1における焼成温度を1100℃とした以外は、実施例1と同様の操作を繰り返して本例のキャリア芯材を得た。
このキャリア芯材の添加剤の添加量と粉体特性、磁気特性、および後述する評価試験結果を表1に示す。
[Example 2]
The Al 2 O 3 powder to be added has an average particle diameter D50 of 0.239 μm, and is weighed so as to be 0.5% by mass in terms of Al with respect to the amount of Fe 2 O 3 powder. A carrier core material of this example was obtained by repeating the same operation as in Example 1 except that the firing temperature was 1100 ° C.
Table 1 shows the amount of the carrier core additive added, powder characteristics, magnetic characteristics, and evaluation test results described later.
〔比較例1〕
添加するAl2O3粒子粉は平均粒径D50が4.607μmのものをFe2O3粉量に対して、Al換算で、1.0質量%となるように秤量した以外は、実施例1と同様の操作を繰り返して本例のキャリア芯材を得た。
このキャリア芯材の添加剤の添加量と粉体特性、磁気特性、および後述する評価試験結果を表1に示す。
[Comparative Example 1]
Except that the Al 2 O 3 particle powder to be added has an average particle diameter D50 of 4.607 μm and was weighed so as to be 1.0% by mass in terms of Al with respect to the amount of Fe 2 O 3 powder. 1 was repeated to obtain a carrier core material of this example.
Table 1 shows the amount of the carrier core additive added, powder characteristics, magnetic characteristics, and evaluation test results described later.
〔比較例2〕
添加するAl2O3粒子粉は平均粒径D50が1.41μmのものをFe2O3粉量に対して、Al換算で、6.0質量%となるように秤量し、実施例1における焼成温度を1100℃とした以外は、実施例1と同様の操作を繰り返して本例のキャリア芯材を得た。
このキャリア芯材の添加剤の添加量と粉体特性、磁気特性、および後述する評価試験結果を表1に示す。
[Comparative Example 2]
The Al 2 O 3 particle powder to be added was weighed so that the average particle diameter D50 was 1.41 μm to be 6.0% by mass in terms of Al with respect to the amount of Fe 2 O 3 powder. A carrier core material of this example was obtained by repeating the same operation as in Example 1 except that the firing temperature was 1100 ° C.
Table 1 shows the amount of the carrier core additive added, powder characteristics, magnetic characteristics, and evaluation test results described later.
[まとめ]
実施例および比較例の磁気特性、電気抵抗の値をみると、同じAl2O3粒子添加量にもかかわらず、Al2O3粒子の粒径が小さいものの方が高い磁気特性、電気抵抗値を示している。このことから、磁気特性、電気抵抗の値はアルミナの粒径に依存していることが分かる。
[Summary]
Magnetic properties of Examples and Comparative Examples, looking at the value of the electrical resistance, the same Al 2 O 3, despite the particle amount, Al 2 O 3 is high magnetic properties towards those particles having a particle size of smaller, electrical resistance Is shown. From this, it can be seen that the values of magnetic characteristics and electric resistance depend on the particle diameter of alumina.
実施例および比較例のキャリア飛散評価を見ると、Al2O3粒子の平均粒径が小さい実施例1、2、のキャリア芯材は、比較例1のキャリア飛散量を「1」と規格化した時、0.31〜0.56となった。これに対し、Al2O3粒子の平均粒径が大きい比較例1、2のキャリアは、1〜3.98となった。このことから添加時のAl2O3粒子の平均粒径が小さい芯材の表面は凹凸が小さくなり、キャリア飛散量を減少させることがわかった。 Looking at the carrier scattering evaluation of Examples and Comparative Examples, the carrier core materials of Examples 1 and 2 in which the average particle diameter of Al 2 O 3 particles is small are normalized with the carrier scattering amount of Comparative Example 1 as “1”. It became 0.31-0.56. On the other hand, the carriers of Comparative Examples 1 and 2 in which the average particle diameter of Al 2 O 3 particles was large were 1 to 3.98. From this, it was found that the surface of the core material having a small average particle diameter of Al 2 O 3 particles at the time of addition had small irregularities and reduced carrier scattering.
実施例2と比較例2とでは同じ温度で焼成したにもかかわらず、BETの値を見ると実施例2が一番低い値を示している。実施例2のキャリア芯材は表面の凹凸が少ないからであると考えられる。 Although Example 2 and Comparative Example 2 were fired at the same temperature, Example 2 shows the lowest value when looking at the BET value. It is considered that the carrier core material of Example 2 has less surface irregularities.
また温度を変えて焼成を行った、実施例1と比較例1とを比較しても、添加するAl2O3粒子粉の平均粒径が小さいほうが、表面の凹凸が少ないことがわかった。
この結果から、キャリア飛散に対するAl2O3粒子の添加、粒径の効果が確認された。
The firing was carried out at different temperatures, as compared with Comparative Example 1 and Example 1, better average particle size of the Al 2 O 3 particles powder to be added is small, it has been found that surface irregularities are small.
From this result, the effect of the addition of Al 2 O 3 particles and the particle size on carrier scattering was confirmed.
以上、実施例1、2、比較例1、2のキャリアに対する、磁気特性、キャリア飛散、破砕試験の評価試験結果から判断すると、実施例1、2に係るキャリアは各評価において良好な結果を示した。従って、実施例1、2に係るキャリアは、電子写真現像剤用のキャリアとして優れたものであると考えられる。
さらに添加時のAl2O3粒子の平均粒径を変化させることによって、表面の形状を変えることができ、粒径の小さいものを添加した場合にはキャリア飛散を抑制でいることがわかった。
As mentioned above, judging from the evaluation test results of magnetic characteristics, carrier scattering, and crushing tests for the carriers of Examples 1 and 2 and Comparative Examples 1 and 2, the carriers according to Examples 1 and 2 show good results in each evaluation. It was. Therefore, the carriers according to Examples 1 and 2 are considered to be excellent as carriers for electrophotographic developers.
Furthermore, it was found that the shape of the surface can be changed by changing the average particle diameter of the Al 2 O 3 particles at the time of addition, and carrier scattering was suppressed when a small particle diameter was added.
次に、表1で示した画像評価試験結果より、次のことが判明した。
まず、初期画像特性においては、比較例2の画質を除き、実施例・比較例ともに非常に良好または良好なレベルであった。しかし、100K枚においては、実施例にも一部レベルの低下が見られたが、比較例では、全ての例において、いずれかの項目において使用不可レベルとなり、交換時期を超過していることが判明した。
Next, the following was found from the image evaluation test results shown in Table 1.
First, with respect to the initial image characteristics, except for the image quality of Comparative Example 2, both the Example and the Comparative Example were very good or good. However, in the 100K sheets, a part of the level was also lowered in the examples, but in the comparative examples, in all the examples, any item was in an unusable level and the replacement time was exceeded. found.
現像画質を保ちながら、当該機器の現像機内における樹脂被覆の剥がれや脱離が低減され、且つキャリア飛散が著しく低減された電子写真現像剤用キャリアとして、複写機、プリンター等の現像機等に適用できる。
As a carrier for electrophotographic developers with reduced image quality and reduced resin coating in the developing machine of the equipment, while significantly reducing carrier scattering, it can be applied to developing machines such as copiers and printers. it can.
Claims (6)
当該マグネタイトまたはソフトフェライト中に0.1質量以上、1質量%以下のAlが含有され、平均表面粗さが0.1μm以上、0.5μm以下であることを特徴とする電子写真現像剤用キャリア芯材。 Magnetite represented by Fe 3 O 4 or general formula (M x Fe 3-x ) O 4 (where M is selected from the group consisting of Mg, Mn, Ca, Ti, Cu, Zn, Sr, Ni) Having at least one kind of metal powder, soft ferrite represented by 0 <x <3),
A carrier for an electrophotographic developer, wherein the magnetite or soft ferrite contains 0.1 to 1% by mass of Al and has an average surface roughness of 0.1 to 0.5 μm. Core material.
前記Al2O3粒子を分散させた媒体液中へ、Fe粉末と、金属粉末とを分散させ、攪拌することによってスラリーを得る工程を行うことを特徴とする請求項1に記載の電子写真現像剤用キャリア芯材の製造方法。 A step of dispersing Al 2 O 3 particles having an average particle diameter of 0.5 μm or less in a medium solution in a powder state or a colloid state; and a Fe powder and a metal in a medium solution in which the Al 2 O 3 particles are dispersed 2. The method for producing a carrier core material for an electrophotographic developer according to claim 1, wherein a step of obtaining a slurry by dispersing the powder and stirring is performed.
得られたスラリーを乾燥し造粒して造粒粉を得る工程と、
得られた造粒粉を、酸素濃度が1%以下の雰囲気下において焼成し、磁性相を有する焼成物を得る工程と、
得られた焼成物を粉砕処理して粉末化し、その後に、所定の粒度分布を持たせる工程と、
を順次行うことを特徴とする請求項1に記載の電子写真現像剤用キャリア芯材の製造方法。
Obtaining the slurry according to claim 2 or 3,
A step of drying and granulating the obtained slurry to obtain a granulated powder;
Firing the obtained granulated powder in an atmosphere having an oxygen concentration of 1% or less to obtain a fired product having a magnetic phase;
The obtained fired product is pulverized and powdered, and then has a predetermined particle size distribution,
The method for producing a carrier core material for an electrophotographic developer according to claim 1, wherein:
An electrophotographic developer comprising the carrier for an electrophotographic developer according to claim 5 and an appropriate toner.
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