JPH096052A - Electrophotographic ferrite carrier - Google Patents
Electrophotographic ferrite carrierInfo
- Publication number
- JPH096052A JPH096052A JP7157335A JP15733595A JPH096052A JP H096052 A JPH096052 A JP H096052A JP 7157335 A JP7157335 A JP 7157335A JP 15733595 A JP15733595 A JP 15733595A JP H096052 A JPH096052 A JP H096052A
- Authority
- JP
- Japan
- Prior art keywords
- ferrite
- ferrite carrier
- carrier
- saturation magnetization
- compsn
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229910000859 α-Fe Inorganic materials 0.000 title claims abstract description 47
- 239000002245 particle Substances 0.000 claims abstract description 29
- 230000005415 magnetization Effects 0.000 claims abstract description 17
- 239000002184 metal Substances 0.000 claims abstract description 8
- 229910052751 metal Inorganic materials 0.000 claims abstract description 8
- 239000002131 composite material Substances 0.000 claims abstract description 7
- 239000012798 spherical particle Substances 0.000 claims abstract 5
- 239000000203 mixture Substances 0.000 claims description 13
- 229920005989 resin Polymers 0.000 claims description 5
- 239000011347 resin Substances 0.000 claims description 5
- 229910015902 Bi 2 O 3 Inorganic materials 0.000 claims description 4
- 229910018663 Mn O Inorganic materials 0.000 claims 1
- 229910016264 Bi2 O3 Inorganic materials 0.000 abstract 1
- 229910017344 Fe2 O3 Inorganic materials 0.000 abstract 1
- 229910044991 metal oxide Inorganic materials 0.000 description 18
- 150000004706 metal oxides Chemical class 0.000 description 18
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 14
- 239000013078 crystal Substances 0.000 description 8
- 238000000034 method Methods 0.000 description 7
- 239000000969 carrier Substances 0.000 description 5
- 230000008859 change Effects 0.000 description 5
- 238000005245 sintering Methods 0.000 description 5
- 230000002159 abnormal effect Effects 0.000 description 4
- 239000000654 additive Substances 0.000 description 4
- 230000000996 additive effect Effects 0.000 description 4
- 238000011161 development Methods 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 230000002093 peripheral effect Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000012546 transfer Methods 0.000 description 4
- 238000011109 contamination Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 108091008695 photoreceptors Proteins 0.000 description 2
- 229920002451 polyvinyl alcohol Polymers 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 230000001680 brushing effect Effects 0.000 description 1
- 239000012876 carrier material Substances 0.000 description 1
- 230000001364 causal effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 230000005308 ferrimagnetism Effects 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000009191 jumping Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229920002050 silicone resin Polymers 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 229920005792 styrene-acrylic resin Polymers 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Landscapes
- Developing Agents For Electrophotography (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、電子写真用二成分系現
像剤に用いられるキャリアに係り、特にＬｉ系フェライ
トキャリアに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier used for a two-component developer for electrophotography, and more particularly to a Li-based ferrite carrier.
【０００２】[0002]
【従来の技術】電子写真の現像法としては磁気ブラシ現
像法、ジャンピング現像法などの種々の方法が知られて
おり、これらの現像法に使用される現像剤としては、ト
ナーのみからなる一成分系現像剤とキャリアとトナーか
ら二成分系現像剤があることはよく知られている。この
うち、二成分系現像剤を構成するキャリアは、適当な摩
擦帯電特性を持ちトナー粒子を吸引すること、粒子の内
外部が緻密であり、粒子の強度が十分で破壊が生じない
こと、粒子が流動性に富むこと、粒子が均一であるこ
と、表面の状態が湿度などによって変わらず種々の特性
が安定であること、耐摩耗性を有すること、飽和磁化や
保磁力などの磁気的特性質が適切なことなどが要求され
る。2. Description of the Related Art As electrophotographic developing methods, various methods such as a magnetic brush developing method and a jumping developing method are known. The developer used in these developing methods is one component consisting of only toner. It is well known that there are two-component developers consisting of a system developer, a carrier and a toner. Of these, the carrier that constitutes the two-component developer has appropriate triboelectrification characteristics and is capable of attracting toner particles, that the inside and outside of the particles are dense, that the particle strength is sufficient and no breakage occurs, Has a high fluidity, the particles are uniform, the surface condition does not change due to humidity, etc., and various characteristics are stable, it has wear resistance, and the magnetic properties such as saturation magnetization and coercive force. Is required to be appropriate.
【０００３】上述した諸特性を満足させる為に従来から
種々のキャリア材料が検討されてきているが、現在広く
使用されているキャリアの一つに鉄粉がある。鉄粉キャ
リアは、通常鉄粉の表面に適当な処理（酸化処理、樹脂
被覆等）を施して使用されているが、長時間使用すると
粒子の表面が物理的あるいは化学的に変化して、トナー
が付着したり、あるいは被覆樹脂が剥離したり、さらに
は使用環境の湿度に敏感になって画像の鮮明度がうすれ
たりするため寿命が短いという欠点がある。Various carrier materials have been studied so far in order to satisfy the above-mentioned various characteristics, and iron powder is one of the carriers which is widely used at present. The iron powder carrier is usually used by applying an appropriate treatment (oxidation treatment, resin coating, etc.) to the surface of the iron powder, but when used for a long time, the surface of the particles physically or chemically changes, resulting in a toner. Has a short life because it adheres to the surface, or the coating resin is peeled off, and it becomes sensitive to the humidity of the operating environment to reduce the sharpness of the image.
【０００４】[0004]
【発明が解決しようとする課題】上記鉄粉キャリアの欠
点を消すべく、フェライト粒子をキャリアを用いること
が特公平3-47502号,同3-52623号,同4-3868号,同6-48393
号及び特開昭62-297857号などにより提案され、実用化
されている。しかしながら、通常のフェライトキャリア
はＺｎを含有するので、最近環境汚染の問題などから有
害金属（Ｚｎ、Ｂａ等）を含む廃棄物に法的な規制もみ
られるなど、フェライトキャリアは実用上の面から対応
を迫られている。すなわち有害金属を含まずに上述した
諸特性を満足する必要があるといった、上記規制をクリ
アするための解決すべき重要な課題をかかえている。In order to eliminate the above-mentioned drawbacks of iron powder carriers, it is preferable to use ferrite particles as carriers in Japanese Patent Publication Nos. 3-47502, 3-52623, 4-3868 and 6-48393.
And Japanese Patent Laid-Open No. 62-297857, and has been put into practical use. However, since ordinary ferrite carriers contain Zn, there are legal restrictions on wastes containing harmful metals (Zn, Ba, etc.) due to environmental pollution and other problems. Is being pressed. That is, it has an important problem to be solved in order to clear the above-mentioned regulations, such as the need to satisfy the above-mentioned characteristics without containing harmful metals.
【０００５】本発明はかかる要望に応えるためになされ
たものであり有害金属を含まない組成を有し、かつ、画
像特性に優れ、寿命の長い電子写真用フェライトキャリ
アを提供することを目的とするものである。The present invention has been made in order to meet such a demand, and an object of the present invention is to provide a ferrite carrier for electrophotography, which has a composition containing no harmful metal, has excellent image characteristics, and has a long life. It is a thing.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するため
に本発明は、Ｍｅ0.5Ｆｅ2.5Ｏ4(Ｍｅは１価の金属を示
す)で表される立方晶の単元系フェライト若しくはＭｅ
またはＦｅの一部をＭｎで置換した複合系フェライトで
あって、モル比でＭｅＯのＬｉＯは４〜３０％、Ｆｅ2
Ｏ3５０〜９５％からなる組成に対し、Ｖ2Ｏ5及びＢｉ2
Ｏ3を０．０１〜１．２重量％含有する組成を有し、も
って結晶組織の粗大化が抑制され、かつ結晶組織が均一
化され、そして飽和磁化が４０emu/g以上、電気抵抗率
が１０3Ω・cm以上の特性を有し、かつ平均粒径が２０〜
１５０μmである球状フェライト粒子をキャリアとした
ことを特徴とするものである。In order to achieve the above object, the present invention provides a cubic unitary ferrite or Me represented by Me 0.5 Fe 2.5 O 4 (Me represents a monovalent metal).
Alternatively, in a composite ferrite in which a part of Fe is replaced by Mn, the molar ratio of LiO of MeO is 4 to 30%, and Fe 2
V 2 O 5 and Bi 2 with respect to the composition of O 3 50 to 95%
O 3 and has a composition containing 0.01 to 1.2 wt%, it is has been suppressed coarsening of crystal structure, and the crystal structure is uniform, and the saturation magnetization is 40 emu / g or more, electrical resistivity It has characteristics of 10 3 Ω · cm or more and an average particle size of 20 to
It is characterized in that spherical ferrite particles of 150 μm are used as the carrier.
【０００７】本発明者等は、従来のフェライトキャリア
について調査、検討した結果、画質に影響を及ぼす帯電
量の調節に関し、電気抵抗を変えるのみでは、キャリア
が使用されるそれぞれの複写機やプリンター等の機構や
現像条件などの違いにより全く効果を発揮しない場合が
あることを知見した。引続きフェライトキャリアの材料
組成と帯電量との関係、およびそれらと画像濃度との関
係等を種々検討した結果、飽和磁化の変化と相俟って容
易に所望の画像濃度が得られるフェライトキャリアの組
成領域を見出し、それに基づいて本発明を完成したもの
である。The present inventors have investigated and studied conventional ferrite carriers, and as a result, regarding the adjustment of the amount of electrification that affects the image quality, changing the electric resistance alone makes it possible to use each carrier such as a copying machine or a printer. It was found that the effect may not be exerted at all due to the difference in the mechanism and development conditions. Subsequently, as a result of various studies on the relationship between the material composition of the ferrite carrier and the charge amount, and the relationship between them and the image density, the composition of the ferrite carrier that can easily obtain the desired image density in combination with the change of the saturation magnetization. The area is found, and the present invention is completed based on the area.
【０００８】本発明において、ＬｉＯ，ＭｎＯ，および
Ｆｅ2Ｏ3の各成分はフェライトキャリアとしての特性を
満足するための基本成分であり、その含有量が、モル比
でＬｉＯ ４〜３０％（好ましくは10〜25%）,ＭｎＯは
０〜５０％(複合系フェライトの場合は好ましくは10〜3
0%),Ｆｅ2Ｏ3 50〜95％(好ましくは60〜90%)の範囲内で
あれば良く、これに特定の金属酸化物を2種以上添加す
ることにより上記目的が達成される。In the present invention, each component of LiO, MnO, and Fe 2 O 3 is a basic component for satisfying the characteristics as a ferrite carrier, and the content thereof is 4 to 30% (preferably in molar ratio) of LiO. Is 10 to 25%) and MnO is 0 to 50% (in the case of composite ferrite, preferably 10 to 3%).
0%), Fe 2 O 3 50 to 95% (preferably 60 to 90%), and the above object can be achieved by adding two or more specific metal oxides.
【０００９】ＭｎＯはＭｅ0.5Ｆｅ2.5Ｏ4の組成に固溶
する際に飽和磁化の向上に寄与し、また、画像濃度に顕
著に影響を及ぼす帯電量制御にも大きく影響する。飽和
磁化はＭｎＯが多い程向上する。飽和磁化が高い(例え
ば５５emu/g以上)場合は、磁気ブラシ法においては現像
剤を保持するマグネットロール上に高い磁気ブラシを形
成するので高い画像濃度が得易いという利点がある。一
方ＭｎＯを含まない単元系のＬｉ0.5Ｆｅ2.5Ｏ4では、
飽和磁化そのものはフェリ磁性の理論により減少するた
めに、マグネットロール上には低い磁気ブラシが形成さ
れるようになる。そのため概して磁気ブラシの穂立ちは
柔らかく、中間調の再現性は良好であるが画像濃度は低
下し易くなる。但し、飽和磁化が低い(例えば５０emu/g
以下)場合でも現像条件(例えば現像ギャップ)を工夫す
ることによって画像濃度、解像度を高めることができる
こともわかった。すなわち、フェライトキャリアは飽和
磁化が高い程画質が向上すると考えられていたが、単元
系Ｌｉ系フェライトのように飽和磁化がそれ程高くない
場合でも、高品質の画像が得られることも判明した。MnO contributes to the improvement of the saturation magnetization when it forms a solid solution in the composition of Me 0.5 Fe 2.5 O 4 , and also has a great influence on the control of the amount of charge that significantly affects the image density. The saturation magnetization increases as the amount of MnO increases. When the saturation magnetization is high (for example, 55 emu / g or more), the magnetic brush method has an advantage that a high image density can be easily obtained because a high magnetic brush is formed on the magnet roll holding the developer. On the other hand, in the unit system Li 0.5 Fe 2.5 O 4 containing no MnO,
Since the saturation magnetization itself is reduced by the theory of ferrimagnetism, a low magnetic brush is formed on the magnet roll. Therefore, the brushing of the magnetic brush is generally soft, and the halftone reproducibility is good, but the image density tends to decrease. However, the saturation magnetization is low (eg 50emu / g
It was also found that the image density and resolution can be increased by devising the developing conditions (for example, the developing gap) even in the following cases. That is, it was thought that the higher the saturation magnetization of the ferrite carrier, the higher the image quality, but it was also found that a high-quality image can be obtained even when the saturation magnetization is not so high as in the case of a unitary Li-based ferrite.
【００１０】なお、上記の効果は本発明に係わる金属酸
化物を加えることによってなし得るものであり、前記組
成範囲内において、Ｖ2Ｏ5とＢｉ2Ｏ3を複合添加するこ
とにより、単元系フェライトではＬｉとＦｅ、複合系フ
ェライトではＬｉ，Ｍｎ，Ｆｅ等が低融点のＶ2Ｏ5及び
Ｂｉ2Ｏ3と相互に化学反応を起こすことによって、焼結
密度の向上(約4.5g/ｃｍ3以上)及び異常結晶粒成長の抑
制(平均結晶粒径を約20μm以下にすること)により、均
質な粒子表面形態が得られるものである。The above effects can be achieved by adding the metal oxide according to the present invention. Within the above composition range, by adding V 2 O 5 and Bi 2 O 3 in combination, a unit system can be obtained. Li and Fe in ferrite and Li, Mn, and Fe in composite ferrite cause chemical reaction with V 2 O 5 and Bi 2 O 3 having low melting points to improve the sintering density (about 4.5 g / cm 2 (3 or more) and suppression of abnormal crystal grain growth (the average crystal grain size is set to about 20 μm or less), a uniform grain surface morphology can be obtained.
【００１１】本発明の目的とする焼結密度の向上と異常
結晶粒成長の抑制のためには、2種の金属酸化物の添加
量は、０．０１重量％以上は必要である。金属酸化物の
含有量が０．５重量％を越えると異常粒成長が発生し始
めるが、添加量が１．２重量％程度までは、本発明に係
わるＬｉ系のフェライトの場合は粒子の表面が荒れて粗
になることはなく、むしろ滑らかになる性質を有してお
り、粒子表面をスチレン−アクリル系樹脂シリコーン樹
脂、フッ素樹脂等で被覆する場合に、使用中に樹脂が剥
離するといった不都合を生ずることはなく、実用が可能
である。金属酸化物の添加量が多くなると焼結密度が低
下することも考慮すると、２種の金属酸化物の添加量は
0.01〜1.2重量％とする必要がある。但し、フェライト
粒子の表面に樹脂を被覆せずにそのまま使用する場合は
トナースペントによる寿命の低下を防止するために上記
添加量は０．６重量％以下が望ましい。In order to improve the sintering density and suppress abnormal crystal grain growth, which is the object of the present invention, the addition amount of the two kinds of metal oxides must be 0.01% by weight or more. Abnormal grain growth begins to occur when the content of the metal oxide exceeds 0.5% by weight, but up to an addition amount of about 1.2% by weight, the surface of the particles in the case of the Li-based ferrite according to the present invention Does not become rough and rough, but rather has a property of becoming smooth, and when the particle surface is coated with styrene-acrylic resin silicone resin, fluororesin, etc., the resin peels off during use. It does not occur, and can be used practically. Considering that the sintering density decreases as the addition amount of metal oxide increases, the addition amount of two kinds of metal oxide is
It should be 0.01 to 1.2% by weight. However, when the ferrite particles are used as they are without being coated with a resin, the addition amount is preferably 0.6% by weight or less in order to prevent a decrease in life due to toner spent.
【００１２】すなわち、本発明においては、モル比でＬ
ｉＯ 4〜30％,ＭｎＯ 0〜50％,Ｆｅ2Ｏ3 50〜95％の基
本組成に低融点の金属酸化物であるＶ2Ｏ5とＢｉ2Ｏ3、
（これらの金属酸化物となり得る金属塩類でもよい）を
1.2重量％以下の少量を添加することによって、飽和磁
化を40〜75emu/g、保磁力を50 Oe以下、電気抵抗を１０
3Ω・cm以上にそれぞれ収めることができるものである。
これらの特性と帯電量及び画質とのからみによって画像
濃度の高い画像が得られるのである。本発明において、
上記の金属酸化物を少量添加することにより焼粒密度が
向上するが、焼結促進剤としては、上記の金属酸化物の
他に例えば、Ａｓ2Ｏ3,Ｓｂ2Ｏ3,Ｂ2Ｏ3,ＳｉＯ2,CaOな
どの金属酸化物を添加しても良い。これらの金属酸化物
の代わりに加熱により金属酸化物となり得る金属化合物
を添加してもよい。That is, in the present invention, the molar ratio L
iO 4 to 30%, MnO 0 to 50%, Fe 2 O 3 50 to 95% and low melting point metal oxides V 2 O 5 and Bi 2 O 3 ,
(Metal salts that can be these metal oxides may be used)
By adding a small amount of 1.2 wt% or less, the saturation magnetization is 40 to 75 emu / g, the coercive force is 50 Oe or less, and the electric resistance is 10
It can be contained in 3 Ω · cm or more.
An image having a high image density can be obtained by considering these characteristics, the charge amount, and the image quality. In the present invention,
The sintering grain density is improved by adding a small amount of the above-mentioned metal oxide. As the sintering accelerator, for example, As 2 O 3 , Sb 2 O 3 , B 2 O 3 may be used in addition to the above-mentioned metal oxide. , Metal oxides such as SiO 2 and CaO may be added. Instead of these metal oxides, a metal compound capable of becoming a metal oxide by heating may be added.
【００１３】また、本発明において、キャリア粒子は、
その平均粒径が20〜150μmの範囲内にある性状のもので
あることが望ましく、特殊な静電記録などの用途の場合
を除いては、粒径が20μm未満の場合には、キャリア飛
散などがあり、一方、粒径が150μmを越える場合には、
画像そのものが粗となり好ましくない。In the present invention, the carrier particles are
It is desirable that the average particle size is within the range of 20 to 150 μm, except for special electrostatic recording applications, if the particle size is less than 20 μm, carrier scattering etc. On the other hand, if the particle size exceeds 150 μm,
The image itself becomes coarse, which is not preferable.
【００１４】また、本発明において、フェライトキャリ
アの飽和磁化値は40〜75emu/gの範囲内にであることが
望ましい。飽和磁化の値が40emu/gより小さい場合には
現像ギャップを狭くしてもマグネットロールとの吸着力
が低下して磁気ブラシが小さくなるため、目標とする高
濃度でかつ鮮明な画像を得ることは困難となり、一方、
飽和磁化が75emu/gを越える場合には、磁力が強いため
に磁気ブラシが鎖状となり易く、中間調の良い画像が得
にくいためである。Further, in the present invention, the saturation magnetization value of the ferrite carrier is preferably within the range of 40 to 75 emu / g. If the saturation magnetization value is less than 40 emu / g, the attraction force with the magnet roll will be reduced and the magnetic brush will be smaller even if the development gap is narrowed, so the target high density and clear image can be obtained. Becomes difficult, while
This is because when the saturation magnetization exceeds 75 emu / g, the magnetic brush is likely to be chained due to the strong magnetic force, and it is difficult to obtain an image with good halftone.
【００１５】また、本発明において、上記フェライトキ
ャリアの保磁力Hcが50 Oeを越える場合には、粒子その
ものが永久磁石の性質を持ちマグネットロール等に強く
付着して現像されるトナーの流動性を悪くするために、
画像むらが発生し良好な画像は得られなくなるので、そ
の保磁力は50 Oe以下であることが望ましく、より好ま
しくは１０ Ｏe以下である。In the present invention, when the coercive force Hc of the ferrite carrier exceeds 50 Oe, the particles themselves have the property of a permanent magnet and strongly adhere to a magnet roll or the like to improve the fluidity of the toner to be developed. To make it worse
Since image unevenness occurs and a good image cannot be obtained, the coercive force is preferably 50 Oe or less, and more preferably 10 Oe or less.
【００１６】さらに本発明においては、、フェライトキ
ャリアは耐摩耗性が大であること、ひいては長寿命化に
つながることから、フェライト粒子の破壊強度は5000g/
cm2以上であることが望ましい。なお、本発明におい
て、キャリアの磁気特性は振動試料型磁力計（東英工業
社製ＶＳＭ−３型）にて最大１０ＫＯｅの磁界中で測定
した値であり、電気抵抗はＤ．Ｃ．１００Ｖ／ｍの電界
中で測定した値である。Further, in the present invention, since the ferrite carrier has high wear resistance, which leads to a longer life, the fracture strength of the ferrite particles is 5000 g /
It is desirable that it is cm 2 or more. In the present invention, the magnetic characteristics of the carrier are values measured by a vibrating sample magnetometer (VSM-3 type manufactured by Toei Industry Co., Ltd.) in a magnetic field of maximum 10 KOe, and the electric resistance is D.I. C. It is a value measured in an electric field of 100 V / m.
【００１７】[0017]
【実施例】以下、本発明を実施例に基づいて、より詳細
に説明する。 （実施例）モル比で、表１に示す各種組成の試料となる
ように原料をそれぞれ秤量し、ボールミルにより混合し
た。得られた混合粉を800〜1000℃で仮焼し、仮焼した
試料をアトライターにより粉砕した。粉砕粉の粒径は、
空気透過法を用いて測定した結果、平均粒径で約1.0μm
であった。次いで、粉砕した試料に、バインダーとして
P.V.A(ポリビニールアルコール)を0.5〜1.0重量％加
え、スプレドライヤーにより造粒した。得られた造粒粉
をアルミナ製の容器に入れて大気中で1200℃で焼成し
た。なお、本発明のキャリアを製造するに際し、造粒粉
を多量に炉に装入して焼成する場合には、焼成の際に粒
成長して粒同志が結合することがあるため、ロータリー
キルン等で試料を回転しながら焼成することが望まし
い。このようにして得られた平均粒径約50μmのフェラ
イト粒子の諸特性を表１に示す。なお、表中の「結晶粒
径」は「平均結晶粒径」である。EXAMPLES The present invention will now be described in more detail based on examples. (Example) The raw materials were weighed so as to obtain samples having various compositions shown in Table 1 in terms of molar ratio, and mixed by a ball mill. The obtained mixed powder was calcined at 800 to 1000 ° C., and the calcined sample was crushed with an attritor. The particle size of the crushed powder is
As a result of measurement using the air permeation method, the average particle size is approximately 1.0 μm.
Met. Then, as a binder to the crushed sample
0.5 to 1.0% by weight of PVA (polyvinyl alcohol) was added, and the mixture was granulated with a spray dryer. The obtained granulated powder was placed in an alumina container and fired at 1200 ° C. in the atmosphere. When manufacturing the carrier of the present invention, when a large amount of granulated powder is charged into a furnace and fired, grain growth may occur during firing and the grains may combine with each other. It is desirable to bake the sample while rotating it. Table 1 shows various characteristics of the thus obtained ferrite particles having an average particle size of about 50 μm. The "crystal grain size" in the table is the "average crystal grain size".
【００１８】[0018]
【表１】 [Table 1]
【００１９】これらの球状フェライト粒子を体積平均粒
径が１０μｍ、Ｄ．Ｃ．４ＫＶ／ｃｍにおける電気抵抗
が１×１０15Ω・cmのトナー（日立金属製ＨＭＴ４３
３）とトナー濃度が４重量％となるように混合して二成
分現像剤を調製し、次の条件で15万枚の連続コピー試験
を行った。These spherical ferrite particles have a volume average particle diameter of 10 μm, D.I. C. Toner with an electric resistance of 1 × 10 15 Ω · cm at 4 KV / cm (HMT43 manufactured by Hitachi Metals)
3) was mixed with 3) so that the toner concentration would be 4% by weight to prepare a two-component developer, and a continuous copy test of 150,000 sheets was conducted under the following conditions.
【００２０】（１）画像形成条件 感光体：ｏｐｃドラム、周速６０ｍｍ／sec、表面電位−
５００Ｖ 現像ロール：外径２０ｍｍのＳＵＳ３０４製スリーブ
（周速１５０mm／sec）の内部に、４極非対称着磁を施
した円筒状フェライト磁石を固定配置。スリーブ上の磁
束密度は現像磁極が８００Ｇ、他の磁極は６００Ｇ。 現像キャップ：０．６mm、ドクターギャップ：０．５ｍ
ｍ 転写：コロナ転写、定着：熱ロール定着〔定着温度１７
０℃、定着圧力(線圧)１Kg／ｃｍ〕 （２）画像形成条件 感光体：ｏｐｃドラム、周速６０mm/sec、表面電位−５
００Ｖ 現像ロール：外径３２mmのＳＵＳ３０４製スリーブ（周
速２５０mm/sec）の内部に、４極非対称着磁を施した円
筒形フェライト磁石を固定配置。スリーブ上の磁束密度
は現像磁極が８００Ｇ、他の磁極は６００Ｇ。 現像キャップ：１．０ｍｍ、ドクターギャップ：０．８
ｍｍ 転写：コロナ転写、定着：熱ロール定着@ 定着温度１７
０℃、定着圧力(線圧)１kg/ｃｍ （注）環境条件はともに２０℃、６０％Ｒ．Ｈ（常
温常湿）(1) Image forming conditions Photoreceptor: opc drum, peripheral speed 60 mm / sec, surface potential-
500V developing roll: A cylindrical ferrite magnet with a 4-pole asymmetric magnetization is fixedly arranged inside a SUS304 sleeve (peripheral speed 150 mm / sec) having an outer diameter of 20 mm. The magnetic flux density on the sleeve is 800G for the developing magnetic pole and 600G for the other magnetic poles. Development cap: 0.6 mm, doctor gap: 0.5 m
m transfer: corona transfer, fixing: hot roll fixing [fixing temperature 17
0 ° C., fixing pressure (linear pressure) 1 kg / cm] (2) Image forming conditions Photoreceptor: opc drum, peripheral speed 60 mm / sec, surface potential −5
00V Developing roll: A SUS304 sleeve with an outer diameter of 32 mm (peripheral speed of 250 mm / sec) has a 4-pole asymmetrically magnetized cylindrical ferrite magnet fixedly arranged therein. The magnetic flux density on the sleeve is 800G for the developing magnetic pole and 600G for the other magnetic poles. Development cap: 1.0 mm, doctor gap: 0.8
mm Transfer: Corona transfer, Fixing: Heat roll fixing @ Fixing temperature 17
0 ℃, Fixing pressure (Linear pressure) 1kg / cm (Note) Environmental conditions are 20 ℃ and 60% R. H (normal temperature and humidity)
【００２１】金属酸化物を含む本発明による上記組成の
試料2〜4、6、7および試料9〜11、13、14はいずれの条件で
も画像濃度1.5〜1.3の範囲内の濃度変化であり、現像条
件による顕著な有意差は認められなかった。しかしなが
ら、金属酸化物を含まない試料1と8の初期の画像濃度は
1.5であったものが連続コピー後は1.2まで低下し、金属
酸化物を含まない試料ではトナーによる汚染、すなわち
スペントトナー量が添加物を含む試料に比べて多く、こ
れは画像濃度に影響を及ぼす帯電量の変化に依存したも
のと考えられる。金属酸化物の添加量が多い試料５と１
２は、焼結密度がやや低下し、均質的な粒子表面が得ら
れず（トナースペントが増大し）、初期の画像濃度は高
いが、連続コピー後は１．１まで低下した。Samples 2 to 4, 6 and 7 and samples 9 to 11, 13 and 14 having the above-mentioned composition containing a metal oxide show a density change within the range of image density of 1.5 to 1.3 under any conditions, No significant difference was observed depending on the developing conditions. However, the initial image densities of Samples 1 and 8 containing no metal oxide were
What was 1.5 decreased to 1.2 after continuous copying, and the sample without metal oxide had more toner contamination, that is, the amount of spent toner was larger than that of the sample with additive, which affects the image density. It is considered that it depends on the change in the charge amount. Samples 5 and 1 containing large amounts of metal oxide
In No. 2, the sintered density was slightly lowered, a uniform particle surface was not obtained (toner spent increased), and the initial image density was high, but it decreased to 1.1 after continuous copying.
【００２２】つぎに、試料1、2、4及び試料8、9、11につい
て、それぞれトナー濃度が4.0重量%となるように上記ト
ナーを加えて現像装置に投入して連続回転（攪拌）テス
トを行った。フェライトキャリア表面のトナーによる汚
染の状態を調べた結果を図１、図２に示す。15万枚のコ
ピーテストに相当する75時間の連続回転では、本発明に
よる試料2と4のキャリア粒子表面へのトナー付着量は0.
5重量％以下で極めて少量であることが確認された。一
方、試料1と8では、トナー付着量は試料2,4,9,11より若
干多い。この差異は添加物の有無によるフェライトキャ
リア粒子表面の均質性と因果関係があり、粒子表面が粗
である程トナー付着量が増大することに起因している。Next, for Samples 1, 2 and 4 and Samples 8, 9 and 11, the above toner was added so that the toner concentration becomes 4.0% by weight, and the mixture was put into a developing device and a continuous rotation (stirring) test was conducted. went. The results of examining the state of toner contamination on the surface of the ferrite carrier are shown in FIGS. 1 and 2. After 75 hours of continuous rotation, which corresponds to a copy test of 150,000 sheets, the amount of toner adhered to the surface of carrier particles of Samples 2 and 4 according to the present invention is 0.
It was confirmed that the amount was 5% by weight or less and was extremely small. On the other hand, in Samples 1 and 8, the toner adhesion amount is slightly larger than in Samples 2, 4, 9 and 11. This difference has a causal relationship with the homogeneity of the ferrite carrier particle surface depending on the presence or absence of the additive, and is due to the fact that the rougher the particle surface, the greater the toner adhesion amount.
【００２３】図３は図１、図２の試料について、電気抵
抗の変化を示したもので、図３から連続回転による長時
間テストによっても、試料2と9の変化量は微少であるこ
とがわかる。このことは換言すればフェライトキャリア
の帯電量変化が僅少であることを意味しており、この結
果からも、本発明のフェライトキャリアは長寿命であ
り、優れた特性を持っていることがわかる。FIG. 3 shows changes in electric resistance of the samples of FIGS. 1 and 2. Even after a long-term test by continuous rotation from FIG. 3, the amounts of changes of samples 2 and 9 are minute. Recognize. In other words, this means that the change in the charge amount of the ferrite carrier is small, and this result also shows that the ferrite carrier of the present invention has a long life and excellent characteristics.
【００２４】なお、上述した本発明の実施例において、
混合機としてボールミルを使用したが、振動ミルまたは
ミキサー等を用いても良い。また、粉砕機としてはアト
ライターを使用したが、これも、ボールミルまたは、振
動ミル等、他の公知の粉砕機を用いても良い。In the above embodiment of the present invention,
Although a ball mill is used as the mixer, a vibration mill or a mixer may be used. Although an attritor was used as the crusher, another known crusher such as a ball mill or a vibration mill may also be used.
【００２５】[0025]
【発明の効果】以上の如く、低融点の金属酸化物を含む
本発明のフェライトキャリアは、無添加のフェライトキ
ャリアに比べて、異常結晶粒成長が抑制され、もってト
ナー汚染が少なく長寿命であり、電子写真装置（複写
機、レーザービームプリンタ等）の現像剤として使用し
た場合にその工業的価値は大である。INDUSTRIAL APPLICABILITY As described above, the ferrite carrier of the present invention containing a metal oxide having a low melting point suppresses abnormal crystal grain growth as compared with a ferrite carrier without addition, and thus has less toner contamination and a long life. When used as a developer for electrophotographic devices (copiers, laser beam printers, etc.), its industrial value is great.
【図１】単元系フェライトの現像装置の連続回転時間と
トナー付着量の関係を示す図である。FIG. 1 is a diagram showing a relationship between a continuous rotation time of a developing device for a unitary ferrite and a toner adhesion amount.
【図２】本発明に係わる複合系フェライトの添加物の有
無による現像装置の連続回転による回転時間とトナー付
着量の関係を示す図である。FIG. 2 is a diagram showing a relationship between a rotation time and a toner adhesion amount due to continuous rotation of the developing device according to the presence or absence of the additive of the composite ferrite according to the present invention.
【図３】単元系及び複合系フェライトの添加物の有無に
よる現像装置の連続回転による回転時間と電気抵抗の関
係を示す図である。FIG. 3 is a diagram showing the relationship between the rotation time and the electric resistance due to continuous rotation of the developing device depending on the presence or absence of the additive of the unitary and composite ferrites.
Claims (5)
示す)で表される立方晶系の単元系フェライト若しくは
ＭｅまたはＦｅの一部をＭｎで置換した複合系フェライ
トであって、モル比でＭｅＯのＬｉＯは4〜30％、Ｍｎ
Ｏは50％以下Ｆｅ2Ｏ3 50〜95％からなる組成に対し、
Ｖ2Ｏ5及びＢｉ2Ｏ3を０．０１〜１．２重量％含有する
組成を有し、飽和磁化値が40emu/g以上、電気抵抗率が
１０3Ω・cm以上、平均粒径が２０〜１５０μmの球状粒
子からなることを特徴とする電子写真用フェライトキャ
リア。1. A cubic system ferrite represented by Me 0.5 Fe 2.5 O 4 (Me represents a monovalent metal) or a composite ferrite obtained by substituting a part of Me or Fe with Mn. , Molar ratio of MeO to LiO is 4 to 30%, Mn
O is 50% or less Fe 2 O 3 50 to 95% of the composition,
It has a composition containing 0.01 to 1.2% by weight of V 2 O 5 and Bi 2 O 3 , a saturation magnetization value of 40 emu / g or more, an electric resistivity of 10 3 Ω · cm or more, and an average particle size of A ferrite carrier for electrophotography, comprising a spherical particle of 20 to 150 μm.
特徴とする請求項１記載の電子写真用フェライトキャリ
ア。2. The ferrite carrier for electrophotography according to claim 1, which has a coercive force Hc of 50 Oe or less.
であることを特徴とする請求項１又は２に記載の電子写
真用フェライトキャリア。3. The ferrite carrier for electrophotography according to claim 1, wherein the strength of the spherical particles is 5000 g / cm 2 or more.
いることを特徴とする請求項１〜３のいずれかに記載の
電子写真用フェライトキャリア。4. The ferrite carrier for electrophotography according to claim 1, wherein the surface of the spherical particles is oxidized or reduced.
ことを特徴とする請求項１〜４のいずれかに記載の電子
写真用フェライトキャリア。5. The ferrite carrier for electrophotography according to claim 1, wherein the surface of the spherical particles is coated with a resin.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7157335A JPH096052A (en) | 1995-06-23 | 1995-06-23 | Electrophotographic ferrite carrier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7157335A JPH096052A (en) | 1995-06-23 | 1995-06-23 | Electrophotographic ferrite carrier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH096052A true JPH096052A (en) | 1997-01-10 |
Family
ID=15647450
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7157335A Pending JPH096052A (en) | 1995-06-23 | 1995-06-23 | Electrophotographic ferrite carrier |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH096052A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005181944A (en) * | 2003-03-13 | 2005-07-07 | Ricoh Co Ltd | Electrostatic latent image developing carrier, developer, developer container, image forming method, and process cartridge |
| EP2107425A1 (en) | 2008-03-31 | 2009-10-07 | Mitsui Mining & Smelting Co., Ltd. | Carrier core material for an electrophotographic developer, carrier, and electrophotographic developer using the carrier |
| JP4763216B2 (en) * | 2000-05-17 | 2011-08-31 | イーストマン コダック カンパニー | Magnetic carrier particles |
| US8039190B2 (en) | 2008-03-31 | 2011-10-18 | Mitsui Mining & Smelting Co., Ltd. | Carrier core material for electrophotographic developer, carrier, and electrophotographic developer using the carrier |
-
1995
- 1995-06-23 JP JP7157335A patent/JPH096052A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4763216B2 (en) * | 2000-05-17 | 2011-08-31 | イーストマン コダック カンパニー | Magnetic carrier particles |
| JP2005181944A (en) * | 2003-03-13 | 2005-07-07 | Ricoh Co Ltd | Electrostatic latent image developing carrier, developer, developer container, image forming method, and process cartridge |
| EP2107425A1 (en) | 2008-03-31 | 2009-10-07 | Mitsui Mining & Smelting Co., Ltd. | Carrier core material for an electrophotographic developer, carrier, and electrophotographic developer using the carrier |
| US7862975B2 (en) | 2008-03-31 | 2011-01-04 | Mitsui Mining & Smelting Co., Ltd. | Carrier core material for an electrophotographic developer, carrier, and electrophotographic developer using the carrier |
| US8039190B2 (en) | 2008-03-31 | 2011-10-18 | Mitsui Mining & Smelting Co., Ltd. | Carrier core material for electrophotographic developer, carrier, and electrophotographic developer using the carrier |
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