JPH08190225A - Carrier for developing electrostatic latent image - Google Patents
Carrier for developing electrostatic latent imageInfo
- Publication number
- JPH08190225A JPH08190225A JP7018619A JP1861995A JPH08190225A JP H08190225 A JPH08190225 A JP H08190225A JP 7018619 A JP7018619 A JP 7018619A JP 1861995 A JP1861995 A JP 1861995A JP H08190225 A JPH08190225 A JP H08190225A
- Authority
- JP
- Japan
- Prior art keywords
- carrier
- magnetic powder
- image
- resin
- electrostatic latent
- 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.)
- Granted
Links
- 239000006247 magnetic powder Substances 0.000 claims abstract description 72
- 229920005989 resin Polymers 0.000 claims abstract description 38
- 239000011347 resin Substances 0.000 claims abstract description 38
- 239000011230 binding agent Substances 0.000 claims abstract description 11
- 239000002245 particle Substances 0.000 claims description 18
- 239000000463 material Substances 0.000 abstract description 12
- 238000004519 manufacturing process Methods 0.000 abstract description 8
- 238000010298 pulverizing process Methods 0.000 abstract description 8
- 230000015572 biosynthetic process Effects 0.000 abstract description 2
- 230000005389 magnetism Effects 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 15
- 238000004898 kneading Methods 0.000 description 10
- 241000519995 Stachys sylvatica Species 0.000 description 7
- 239000002994 raw material Substances 0.000 description 7
- 239000000969 carrier Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 229910000859 α-Fe Inorganic materials 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 229910002012 Aerosil® Inorganic materials 0.000 description 1
- 241000282320 Panthera leo Species 0.000 description 1
- 230000000740 bleeding effect Effects 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 210000005069 ears Anatomy 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000003273 ketjen black Substances 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 230000000452 restraining effect Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Landscapes
- Developing Agents For Electrophotography (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、複写機やプリンター
等の画像形成装置において、感光体等の像担持体に形成
された静電潜像を現像するのに使用する静電潜像現像用
キャリアに係り、特に、樹脂中に磁性粉が分散されたバ
インダー型の静電潜像現像用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 an electrostatic latent image developing device used for developing an electrostatic latent image formed on an image bearing member such as a photoconductor in an image forming apparatus such as a copying machine or a printer. The present invention relates to a carrier, and more particularly to a binder type electrostatic latent image developing carrier in which magnetic powder is dispersed in a resin.
【０００２】[0002]
【従来の技術】従来より、複写機やプリンター等の画像
形成装置においては、感光体等の像担持体に形成された
静電潜像を現像するにあたり、その現像剤として、トナ
ーとキャリアとを混合させたものが広く利用されてい
た。2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, when developing an electrostatic latent image formed on an image bearing member such as a photoconductor, a toner and a carrier are used as developers. The mixture was widely used.
【０００３】そして、このようにトナーと混合させるキ
ャリアとしては、従来、鉄やフェライト等の粉体を用い
たものの他に、これらの磁性粉を樹脂に分散させたバイ
ンダー型のものが知られていた。As a carrier to be mixed with the toner in this way, conventionally, in addition to a carrier using powder of iron, ferrite, etc., a binder type carrier in which these magnetic powders are dispersed in a resin is known. It was
【０００４】ここで、鉄やフェライト等の粉体からなる
キャリアは一般に低抵抗であり、このため、このキャリ
アを使用して現像を行なった場合、像担持体上における
電荷がこのキャリアを通して流れ、これにより形成され
た画像にぬけが生じたり、現像スリーブからの注入電荷
によりキャリアが像担持体に付着したりするという問題
があり、さらにこのようなキャリアによって形成される
磁気ブラシの穂が一般に硬く、写真原稿等のハーフトー
ン画像を現像する際に筋状のむらが発生する等の問題が
あった。Here, a carrier made of powder such as iron or ferrite generally has a low resistance. Therefore, when development is performed using this carrier, the charge on the image carrier flows through this carrier, Due to this, there is a problem that the image formed is bleeding, or the carrier adheres to the image carrier due to the charge injected from the developing sleeve. Furthermore, the ears of the magnetic brush formed by such a carrier are generally hard. However, there is a problem that streaky unevenness occurs when developing a halftone image such as a photographic original.
【０００５】このため、近年においては、上記のように
樹脂に磁性粉を分散させたバインダー型のキャリアが注
目されるようになった。Therefore, in recent years, a binder type carrier in which magnetic powder is dispersed in a resin as described above has been receiving attention.
【０００６】しかし、このように樹脂に磁性粉を分散さ
せたバインダー型のキャリアは一般に磁気力が弱く、こ
のキャリアに対するマグネットローラ等による磁気拘束
力が弱くなって、このキャリアが現像スリーブから離れ
て像担持体に付着し、これにより形成される画像にノイ
ズが発生したり、付着したキャリアによって像担持体が
傷ついたりする等の問題があった。However, the binder type carrier in which the magnetic powder is dispersed in the resin as described above generally has a weak magnetic force, and the magnetic restraining force by the magnet roller or the like against this carrier is weakened, and the carrier is separated from the developing sleeve. There are problems that the image carrier adheres to the image carrier, noise is generated in an image formed by the image carrier, and the carrier adhered to the image carrier damages the image carrier.
【０００７】そこで、従来においても、上記のバインダ
ー型キャリアにおいて、樹脂中に磁性粉を多く含有させ
てその磁気力を高めることが行なわれるようになった。Therefore, conventionally, in the above binder type carrier, a large amount of magnetic powder is contained in the resin to enhance the magnetic force.
【０００８】しかし、一般に使用されている磁性粉を樹
脂中に高密度で充填させるようにすると、キャリアを製
造するにあたって、樹脂と磁性粉とを混練させた混練物
を粉砕することが困難になり、キャリアの生産効率が著
しく低下したり、混練物を粉砕した際に、混練物中にお
ける磁性粉が遊離し、このように遊離した磁性粉がキャ
リアに付着してしまい、このようなキャリアを用いて現
像を行なった場合、遊離した磁性粉が像担持体の画像部
分に供給されて、像担持体における電荷が消失し、形成
される画像に白ぬけが生じる等の問題があった。[0008] However, if the generally used magnetic powder is filled in the resin at a high density, it becomes difficult to pulverize the kneaded product obtained by kneading the resin and the magnetic powder when manufacturing the carrier. The production efficiency of the carrier is remarkably reduced, or when the kneaded product is crushed, the magnetic powder in the kneaded product is released, and the magnetic powder thus released adheres to the carrier. When the development is carried out, the released magnetic powder is supplied to the image portion of the image bearing member, the charge on the image bearing member disappears, and there is a problem that a white image is generated in the formed image.
【０００９】また、上記のように樹脂中に磁性粉を高密
度で充填させると、一般にキャリアの流動性が悪くな
り、これによりトナーを十分に混合撹拌させて適切に帯
電させることができなくなり、不良帯電トナーによって
形成される画像に地肌かぶりが生じたり、現像装置内に
おける現像剤に片寄りが生じて、形成された画像に濃度
むらが発生する等の問題があった。Further, when the magnetic powder is filled in the resin at a high density as described above, the fluidity of the carrier is generally deteriorated, whereby the toner cannot be sufficiently mixed and stirred to be appropriately charged. There are problems that background fogging occurs in the image formed by the poorly charged toner, and the developer in the developing device is biased, resulting in uneven density in the formed image.
【００１０】[0010]
【発明が解決しようとする課題】この発明は、複写機や
プリンター等の画像形成装置において、感光体等の像担
持体に形成された静電潜像を現像するのに使用する静電
潜像現像用キャリアにおける上記のような様々な問題を
解決することを課題とするものである。SUMMARY OF THE INVENTION The present invention is directed to an electrostatic latent image used for developing an electrostatic latent image formed on an image bearing member such as a photoconductor in an image forming apparatus such as a copying machine or a printer. It is an object of the present invention to solve the above-mentioned various problems in a developing carrier.
【００１１】すなわち、この発明においては、上記のよ
うに樹脂中に磁性粉が分散されたバインダー型の静電潜
像現像用キャリアにおいて、磁性粉が樹脂中に均一に分
散した状態で高密度に充填されて十分な磁気力を有し、
現像時に像担持体に付着するということがなく、またそ
の製造時において樹脂と磁性粉等との混練物を粉砕する
ことが容易に行なえると共に、その粉砕時に遊離した磁
性粉が発生するということも少なく、良好な画像形成が
安定して行なえる静電潜像現像用キャリアを提供するこ
とを課題とするものである。That is, according to the present invention, in the binder type electrostatic latent image developing carrier in which the magnetic powder is dispersed in the resin as described above, the magnetic powder is densely dispersed in the resin. Filled with enough magnetic force,
It does not adhere to the image bearing member at the time of development, and the kneaded product of resin and magnetic powder can be easily crushed during its production, and magnetic powder released during crushing is generated. It is an object of the present invention to provide a carrier for developing an electrostatic latent image, which is capable of stably forming a good image with a small amount.
【００１２】[0012]
【課題を解決するための手段】この発明においては、上
記のような課題を解決するため、樹脂中に磁性粉が分散
されたバインダー型の静電潜像現像用キャリアにおい
て、上記磁性粉の比表面積が８〜１２ｍ2 ／ｇの範囲に
あり、樹脂中にこの磁性粉が８５〜９０重量％含有され
ると共に、このキャリアにおける応力−歪み特性の降伏
点が２０００〜３０００ｋｇ／ｃｍ2 の範囲にありかつ
この降伏点での歪み量が４００〜１０００μｍ／ｃｍの
範囲にあり、またこのキャリアにおける動的電流値が３
０〜１５０ｎＡの範囲で、その平均粒径が３０〜８０μ
ｍの範囲にある静電潜像現像用キャリアを開発したので
ある。According to the present invention, in order to solve the above problems, in a binder type electrostatic latent image developing carrier in which magnetic powder is dispersed in resin, the ratio of the magnetic powder is The surface area is in the range of 8 to 12 m 2 / g, the magnetic powder is contained in the resin in an amount of 85 to 90% by weight, and the yield point of the stress-strain characteristic of the carrier is in the range of 2000 to 3000 kg / cm 2 . And the amount of strain at this yield point is in the range of 400 to 1000 μm / cm, and the dynamic current value in this carrier is 3
In the range of 0 to 150 nA, the average particle size is 30 to 80 μm.
We developed a carrier for developing electrostatic latent images in the range of m.
【００１３】ここで、この発明における静電潜像現像用
キャリアにおいて、樹脂中に分散させる磁性粉として、
その比表面積が８〜１２ｍ2 ／ｇの範囲にあるものを用
いるようにしたのは、磁性粉における比表面積が８ｍ2
／ｇより小さくなった大きな粒径の磁性粉を用いると、
キャリアの表面に表れる磁性粉の面積が大きくなってキ
ャリアの抵抗値が低下し、現像時に像担持体における電
荷がこのキャリアを通して流れ、形成される画像に白ぬ
け等のノイズが発生する一方、その比表面積が１２ｍ2
／ｇより大きくなった小さい粒径の磁性粉を用いると、
樹脂中にこの磁性粉を上手く均一に結着させた状態で高
密度に充填させることができなくなるためである。Here, in the carrier for developing an electrostatic latent image according to the present invention, as magnetic powder to be dispersed in resin,
The specific surface area is to use a thing in a range of 8 to 12 m 2 / g, the specific surface area of magnetic powder 8m 2
If a magnetic powder with a large particle size smaller than / g is used,
The area of the magnetic powder appearing on the surface of the carrier becomes large and the resistance value of the carrier decreases, and the charge on the image carrier flows through this carrier during development, and noise such as white spots occurs in the formed image, while Specific surface area is 12m 2
If a magnetic powder with a small particle size larger than / g is used,
This is because the magnetic powder cannot be densely packed in a state where the magnetic powder is successfully and uniformly bound in the resin.
【００１４】また、上記のキャリアの樹脂中における磁
性粉の量が８５〜９０重量％の範囲になるようにしたの
は、磁性粉の量が８５重量％より少ないと、得られたキ
ャリアの磁気力が弱く、前記のように像担持体にキャリ
アが付着して形成される画像にノイズが生じたり、像担
持体が付着したキャリアによって傷ついたりする一方、
磁性粉の量が９０重量％より多くなると、磁性粉が樹脂
中に均一に分散されるようにして混練することが困難に
なり、粉砕時に磁性粉が遊離してしまい、磁性粉が上手
く樹脂に結着されたキャリアを得ることが困難になるた
めである。The amount of the magnetic powder in the resin of the above carrier is set to be in the range of 85 to 90% by weight because when the amount of the magnetic powder is less than 85% by weight, the magnetic property of the obtained carrier is reduced. The force is weak, as described above, noise is generated in the image formed by the carrier attached to the image carrier, or the image carrier is damaged by the carrier attached to the image carrier.
When the amount of the magnetic powder is more than 90% by weight, it becomes difficult to knead the magnetic powder so that the magnetic powder is uniformly dispersed in the resin, and the magnetic powder is released during the pulverization, so that the magnetic powder is well converted into the resin. This is because it becomes difficult to obtain a bound carrier.
【００１５】また、このキャリアにおける応力−歪み特
性の降伏点が２０００〜３０００ｋｇ／ｃｍ2 の範囲に
なるようにしたのは、その降伏点が２０００ｋｇ／ｃｍ
2 より小さいと、樹脂中に磁性粉が均一に分散された状
態で結着されておらず、樹脂と磁性粉等との混練物を粉
砕してキャリアを製造した際に、遊離した磁性粉が生
じ、この磁性粉がキャリア付着している可能性が高い一
方、この降伏点が３０００ｋｇ／ｃｍ2 より大きいと、
樹脂と磁性粉等との混練物を粉砕してキャリアを製造す
ることが非常に困難になり、キャリアの生産効率が著し
く低下するためである。Further, the stress in the carrier - the yield point of the distortion characteristic is to be in the range of 2000~3000kg / cm 2, the yield point is 2000 kg / cm
If it is less than 2 , the magnetic powder is not bound in the resin in a uniformly dispersed state, and when the carrier is manufactured by crushing the kneaded product of the resin and the magnetic powder, the released magnetic powder is It is highly possible that this magnetic powder adheres to the carrier, while the yield point is higher than 3000 kg / cm 2 ,
This is because it becomes very difficult to manufacture a carrier by pulverizing a kneaded product of a resin and magnetic powder, and the production efficiency of the carrier is significantly reduced.
【００１６】また、上記の降伏点での歪み量が４００〜
１０００μｍ／ｃｍの範囲になるようにしたのは、その
歪み量が４００μｍ／ｃｍより小さいと、樹脂中に磁性
粉が均一に分散された状態で結着されておらず、樹脂と
磁性粉等との混練物を粉砕してキャリアを製造した際
に、遊離した磁性粉が生じ、この磁性粉がキャリア付着
している可能性が高い一方、その歪み量が１０００μｍ
／ｃｍより大きいと、樹脂と磁性粉等との混練物を粉砕
してキャリアを製造することが非常に困難になり、キャ
リアの生産効率が著しく低下するためである。The strain amount at the yield point is 400 to
The reason why the range of 1000 μm / cm is set is that when the strain amount is less than 400 μm / cm, the magnetic powder is not bound in the resin evenly dispersed, and the resin and the magnetic powder are not bound to each other. When a carrier is produced by crushing the kneaded product of No. 1, free magnetic powder is generated, and it is highly possible that this magnetic powder is attached to the carrier, but the strain amount is 1000 μm.
If it is larger than / cm, it becomes very difficult to pulverize the kneaded material of the resin and the magnetic powder to produce a carrier, and the production efficiency of the carrier is significantly reduced.
【００１７】また、この発明において、キャリアの動的
電流値が３０〜１５０ｎＡの範囲になるようにしたの
は、キャリアにおける動的電流値が３０ｎＡより小さい
と、キャリアの抵抗値が高くなりすぎ、像担持体にトナ
ーを供給した際にキャリアに残るカウンターチャージに
より、像担持体にトナーを十分に供給することができな
くなって現像効率が悪くなる一方、その動的電流値が１
５０ｎＡより大きいと、キャリアの抵抗値が低くなりす
ぎ、像担持体における電荷がキャリアを通して流れ、形
成される画像に白ぬけ等が発生するためである。Further, in the present invention, the dynamic current value of the carrier is set in the range of 30 to 150 nA because the resistance value of the carrier becomes too high when the dynamic current value in the carrier is less than 30 nA. Due to the counter charge remaining in the carrier when the toner is supplied to the image carrier, the toner cannot be sufficiently supplied to the image carrier and the developing efficiency is deteriorated, while the dynamic current value is 1
This is because if it is larger than 50 nA, the resistance value of the carrier becomes too low, the charge in the image carrier flows through the carrier, and white spots or the like occur in the formed image.
【００１８】ここで、キャリアにおける動的電流値につ
いては、図１に示すように、内部にマグネットローラ１
が設けられて磁束密度が１０００ガウスになったスリー
ブローラ２上に５ｇのキャリア３を供給すると共に、こ
のスリーブローラ２と電極管４との間隔を１ｍｍに設定
し、上記マグネットローラ１を５０ｒｐｍで回転させる
と共に、電源５から５００Ｖのバイアス電圧を印加し、
キャリアを通して電極管４に流れた電流値を電流計６に
よって測定し、この電流値を動的電流値として表した。As for the dynamic current value in the carrier, as shown in FIG.
Is supplied to the sleeve roller 2 having a magnetic flux density of 1000 gauss, 5 g of the carrier 3 is supplied, the gap between the sleeve roller 2 and the electrode tube 4 is set to 1 mm, and the magnet roller 1 is rotated at 50 rpm. While rotating, apply a bias voltage of 500V from the power supply 5,
The current value flowing through the carrier into the electrode tube 4 was measured by the ammeter 6, and this current value was expressed as a dynamic current value.
【００１９】また、この発明において、キャリアの平均
粒径が３０〜８０μｍの範囲になるようにしたのは、そ
の粒径が３０μｍより小さいと、キャリアにおける磁気
力が低下し、像担持体にキャリアが付着したり、キャリ
アの流動性が悪くなり、形成される画像に濃度むら等が
生じる一方、その粒径が８０μｍより大きくなると、キ
ャリアの抵抗値が低下して、形成される画像に白ぬけが
生じたり、トナーに対する帯電性が悪くなって、形成さ
れる画像にトナーの地肌かぶりが生じたりするためであ
る。Further, in the present invention, the average particle size of the carrier is set in the range of 30 to 80 μm. When the particle size is smaller than 30 μm, the magnetic force in the carrier decreases and the carrier for the image carrier is reduced. And the flowability of the carrier deteriorates, resulting in density unevenness in the formed image. On the other hand, when the particle size is more than 80 μm, the resistance value of the carrier decreases and the formed image is white. Is caused, or the toner is deteriorated in charging property, and the toner is fogged on the background of the formed image.
【００２０】[0020]
【作用】この発明における静電潜像現像用キャリアにお
いては、樹脂中に磁性粉を分散させたバインダー型のキ
ャリアにおいて、用いる磁性粉の比表面積や、樹脂中に
おけるこの磁性粉の含有量や、キャリアにおける応力−
歪み特性の降伏点及びこの降伏点での歪み量や、その動
的電流値、さらにはその平均粒径を上記の範囲になるよ
うにしたため、磁性粉が樹脂中に高密度に充填されて十
分な磁気力を有すると共に、この磁性粉がキャリア中に
均一に分散されて十分に結着された状態となり、樹脂と
磁性粉等との混練物を粉砕してキャリアを製造すること
が容易になると共に、その粉砕時に遊離した磁性粉が発
生して、キャリアに付着するということも少なく、また
その流動性や抵抗値も適切にな状態になっている。In the electrostatic latent image developing carrier of the present invention, in the binder type carrier in which the magnetic powder is dispersed in the resin, the specific surface area of the magnetic powder used, the content of the magnetic powder in the resin, Stress in carrier-
The yield point of strain characteristics, the amount of strain at this yield point, its dynamic current value, and its average particle size were set within the above range, so that the magnetic powder was sufficiently packed in the resin at a high density. In addition to having a strong magnetic force, this magnetic powder is evenly dispersed in the carrier and is sufficiently bound, and it becomes easy to manufacture a carrier by pulverizing a kneaded material of resin and magnetic powder and the like. At the same time, it is unlikely that free magnetic powder is generated during the pulverization and adheres to the carrier, and the fluidity and the resistance value are in an appropriate state.
【００２１】そして、この発明における静電潜像現像用
キャリアを用いて現像を行なった場合、像担持体にキャ
リアが付着したり、遊離した磁性粉によって像担持体の
電荷が消されて画像部分に白ぬけ等が生じたりするとい
うことがなく、またトナーが適切に帯電されるようにな
ると共に、現像装置内において現像剤に片寄りが生じる
ということも少なくなる。When the electrostatic latent image developing carrier according to the present invention is used for development, the carrier adheres to the image bearing member or the released magnetic powder erases the electric charge of the image bearing member and the image portion is removed. There is no occurrence of white spots on the surface, the toner is appropriately charged, and the deviation of the developer in the developing device is reduced.
【００２２】[0022]
【実施例】以下、この発明の実施例に係る静電潜像現像
用キャリアについて具体的に説明すると共に、比較例を
挙げ、この実施例におけるキャリアが優れていることを
明らかにする。EXAMPLES The electrostatic latent image developing carrier according to the examples of the present invention will be specifically described below, and comparative examples will be given to clarify that the carriers in this example are excellent.
【００２３】（実施例１〜４）これらの実施例において
は、ポリエステル樹脂（花王社製，タフトンＮＥ１１１
０）を１００重量部、比表面積が９．７ｍ2 ／ｇのフェ
ライトからなる磁性粉を７００重量部（樹脂中における
含有量８７．５重量％）、カーボンブラック（ライオン
油脂社製，ケッチェンブラック）を２重量部、シリカ
（日本アエロジル社製，＃２００）を１．５重量部の割
合で加えた原料を用い、それぞれこの原料３ｋｇをヘン
シェルミキサ（三井三池社製）により下記の表１に示す
混合条件で混合させた。そして、このように混合させた
混合物を２回分合わせ、それぞれ６ｋｇの混合物を加圧
ニーダ（森山製作所社製）により表１に示す混練条件で
混練した。(Examples 1 to 4) In these examples, a polyester resin (manufactured by Kao Corporation, Tuffton NE111) was used.
0) 100 parts by weight, 700 parts by weight of magnetic powder made of ferrite having a specific surface area of 9.7 m 2 / g (content in resin: 87.5% by weight), carbon black (Ketjen Black manufactured by Lion Oil and Fat Co., Ltd.) 2) by weight and silica (manufactured by Nippon Aerosil Co., Ltd., # 200) in a ratio of 1.5 parts by weight, and 3 kg of each raw material are shown in Table 1 below by a Henschel mixer (manufactured by Mitsui Miike). They were mixed under the mixing conditions shown. Then, the mixture thus mixed was combined twice, and 6 kg of each mixture was kneaded with a pressure kneader (manufactured by Moriyama Seisakusho) under the kneading conditions shown in Table 1.
【００２４】[0024]
【表１】 [Table 1]
【００２５】そして、上記のようにして得た各混練物を
一辺の長さが１ｃｍになった立方体に成型し、各混練物
における応力−歪み特性を圧縮試験機（インストロン社
製）を用いて測定し、その結果を図２〜５に示すと共
に、各混練物における降伏点及びこの降伏点における歪
み量を求め、その結果を下記の表２に示した。Then, each kneaded product obtained as described above is molded into a cube having a side length of 1 cm, and the stress-strain characteristics of each kneaded product are measured using a compression tester (Instron). 2-5, the yield point of each kneaded product and the amount of strain at this yield point were determined, and the results are shown in Table 2 below.
【００２６】次に、上記のようにして得た各混練物を粗
粉砕し、ジェットミルで微粉砕した後、これを分級し、
さらに後処理を行ない、平均粒径が５０μｍになった実
施例１〜４の各静電潜像現像用キャリアを得た。Next, each kneaded material obtained as described above is roughly pulverized, finely pulverized by a jet mill, and then classified,
Further post-treatment was performed to obtain each electrostatic latent image developing carrier of Examples 1 to 4 having an average particle size of 50 μm.
【００２７】そして、上記の各キャリアについて、前記
の図１に示した装置を使用して前記の条件の下で、各キ
ャリアにおける動的電流値を測定し、その結果を下記の
表２に合わせて示した。Then, for each of the above carriers, the dynamic current value in each carrier was measured under the above conditions using the apparatus shown in FIG. 1, and the results are shown in Table 2 below. Showed.
【００２８】[0028]
【表２】 [Table 2]
【００２９】（比較例１〜７）比較例１においては、上
記実施例における原料中の磁性粉の割合を３００重量部
（樹脂中における含有量７５．０重量％）にし、それ以
外は上記実施例１と同様にして平均粒径が５０μｍにな
ったキャリアを得た。(Comparative Examples 1 to 7) In Comparative Example 1, the ratio of the magnetic powder in the raw material in the above Example was set to 300 parts by weight (content in resin: 75.0% by weight), and otherwise the above Example. In the same manner as in Example 1, a carrier having an average particle size of 50 μm was obtained.
【００３０】比較例２においては、磁性粉として比表面
積が４．６ｍ2 ／ｇのフェライトからなる磁性粉を用い
るようにし、それ以外は上記実施例１と同様にして平均
粒径が５０μｍになったキャリアを得た。In Comparative Example 2, magnetic powder made of ferrite having a specific surface area of 4.6 m 2 / g was used as the magnetic powder, and otherwise the average particle size was 50 μm in the same manner as in Example 1 above. Got a career.
【００３１】比較例３においては、上記実施例１と同じ
原料を使用する一方、上記のヘンシェルミキサによる混
合条件及び加圧ニーダによる混練条件を下記の表３に示
すように変更し、それ以外は上記実施例１と同様にして
粒径が約５０μｍになったキャリアを得た。In Comparative Example 3, the same raw materials as in Example 1 were used, while the mixing conditions by the Henschel mixer and the kneading conditions by the pressure kneader were changed as shown in Table 3 below, and otherwise the same. In the same manner as in Example 1 above, a carrier having a particle size of about 50 μm was obtained.
【００３２】比較例４においては、上記実施例１と同じ
原料を使用し、混練時における混合物の量を３ｋｇにす
ると共に、上記のヘンシェルミキサによる混合条件及び
加圧ニーダによる混練条件を下記の表３に示すように変
更させて混練物を得た。そして、この混練物を粗粉砕し
た後、ジェットミルにより微粉砕を行なったが、その粉
砕効率が非常に悪く、平均粒径が５０μｍのキャリアの
収率が３０％程度と非常に低く、製品化に適していなか
った。In Comparative Example 4, the same raw materials as in Example 1 were used, the amount of the mixture at the time of kneading was 3 kg, and the mixing conditions by the above Henschel mixer and the kneading conditions by the pressure kneader were as shown in the table below. A kneaded material was obtained by changing the method as shown in 3. Then, this kneaded product was roughly crushed and then finely crushed by a jet mill, but the crushing efficiency was very poor, and the yield of carriers having an average particle size of 50 μm was as low as about 30%. Was not suitable for.
【００３３】比較例５においては、上記実施例１と同じ
原料を使用し、混練時における混合物の量を３ｋｇにす
ると共に、上記のヘンシェルミキサによる混合条件及び
加圧ニーダによる混練条件を下記の表３に示すように変
更させて混練物を得た。そして、この混練物を粗粉砕し
た後、ジェットミルにより微粉砕を行なったが、比較例
４の場合と同様にその粉砕効率が非常に悪く、平均粒径
が５０μｍのキャリアの収率が３０％程度と非常に低
く、製品化に適していなかった。In Comparative Example 5, the same raw materials as in Example 1 were used, the amount of the mixture at the time of kneading was set to 3 kg, and the mixing conditions by the Henschel mixer and the kneading condition by the pressure kneader were shown in the following table. A kneaded material was obtained by changing the method as shown in 3. Then, this kneaded product was roughly pulverized and then finely pulverized by a jet mill. However, as in Comparative Example 4, the pulverization efficiency was very poor, and the yield of the carrier having an average particle diameter of 50 μm was 30%. It was very low and not suitable for commercialization.
【００３４】[0034]
【表３】 [Table 3]
【００３５】比較例６においては、上記実施例１と同じ
原料を使用すると共に混合条件及び混練条件も同じにし
て混練物を得た後、この混練物を粉砕及び分級する条件
を変更し、平均粒径が２０μｍになったキャリアを得
た。In Comparative Example 6, the same raw materials as in Example 1 were used, and the same mixing and kneading conditions were used to obtain a kneaded product. Then, the conditions for pulverizing and classifying the kneaded product were changed, and the average value was obtained. A carrier having a particle size of 20 μm was obtained.
【００３６】比較例７においても、上記比較例６と同様
に、実施例１と同じ原料を使用すると共に混合条件及び
混練条件も同じにして混練物を得た後、この混練物を粉
砕及び分級する条件を変更し、平均粒径が１００μｍに
なったキャリアを得た。Also in Comparative Example 7, as in Comparative Example 6, the same raw materials as in Example 1 were used, and the same kneading conditions and kneading conditions were used to obtain a kneaded product, which was then crushed and classified. The conditions were changed to obtain a carrier having an average particle size of 100 μm.
【００３７】そして、上記の比較例１〜７において、そ
れぞれ粉砕を行なう前の混練物の段階で、上記の実施例
の場合と同様に、各混練物をそれぞれ一辺の長さが１ｃ
ｍになった立方体に成型し、各混練物における応力−歪
み特性を前記の圧縮試験機を用いて測定し、各混練物に
おける降伏点及びその降伏点における歪み量を求め、そ
の結果を下記の表４に示した。In each of Comparative Examples 1 to 7 described above, at the stage of the kneaded material before crushing, each kneaded material has a side length of 1c, as in the case of the above-mentioned embodiment.
The kneaded product was molded into a cube having a size of m, the stress-strain characteristics of each kneaded product were measured using the compression tester, the yield point of each kneaded product and the amount of strain at the yield point were determined, and the results are shown below. The results are shown in Table 4.
【００３８】また、上記比較例１〜３，６，７の各キャ
リアについては、上記実施例の場合と同様にしてその動
的電流値を測定し、その結果を表４に合わせて示した。The dynamic current values of the carriers of Comparative Examples 1 to 3, 6 and 7 were measured in the same manner as in the above example, and the results are also shown in Table 4.
【００３９】[0039]
【表４】 [Table 4]
【００４０】次に、上記実施例１〜４及び比較例１〜
３，６，７の各キャリアを市販の複写機（ミノルタ社製
ＥＰ−５４００）に使用して１万枚の耐刷試験を行な
い、各キャリアのトナーに対する帯電性，各キャリアの
流動性，像担持体に対するキャリアの付着，形成された
画像における白ぬけ及び地肌かぶりの評価を行ない、そ
の結果を下記の表５に示した。Next, the above Examples 1 to 4 and Comparative Examples 1 to
Each of the carriers 3, 6 and 7 was used in a commercially available copying machine (EP-5400 manufactured by Minolta Co., Ltd.) to perform a printing durability test on 10,000 sheets, and the chargeability of each carrier with respect to toner, the fluidity of each carrier, and the image The adhesion of the carrier to the carrier, the white spots and the background fog in the formed image were evaluated, and the results are shown in Table 5 below.
【００４１】ここで、この表５において、キャリアのト
ナーに対する帯電性については、帯電性が上昇したキャ
リアによるトナーの帯電量をｑ1 、帯電性が低下したキ
ャリアによるトナーの帯電量ｑ2 、初期のキャリアによ
るトナーの帯電量ｑ0 とした場合に、（ｑ1 −ｑ2 ）／
ｑ0 の値が、０．４未満でトナーの帯電量の変化が非常
に少ない場合を◎、０．４〜０．７の場合を○、０．７
〜１．０の場合を△、１．０以上の場合を×で示した。
また、キャリアの流動性については、上記の複写機によ
り５千枚の複写を行なった後で、黒ベタ画像の複写を行
ない、その通紙方向と直交する方向に２０ｃｍ離れた２
点においてそれぞれの画像濃度をマクベス濃度計により
測定して上記の２点における画像濃度差を測定し、その
画像濃度差が０．０５未満と少なくなっている場合を
◎、０．０５〜０．１の場合を○、０．１〜０．２の場
合を△、０．２以上の場合を×で示した。また、像担持
体に対するキャリアの付着，形成された画像における白
抜け及び地肌かぶりについては、１万枚の耐刷試験中に
おいて、千枚毎における画像を目視評価し、それぞれ最
悪の状態のものについて評価を行なうようにし、全くこ
れらが発生していないレベルを５、若干発生しているが
実用上問題ないレベルを４、実用上の下限レベルを３、
実用上問題が発生するレベルを２、問題が大きいレベル
を１で表すようにした。Here, in Table 5, regarding the chargeability of the carrier to the toner, the charge amount of the toner by the carrier whose chargeability has increased is q 1 , the charge amount of the toner by the carrier whose chargeability has decreased q 2 , and the initial value. when the charge amount q 0 of toner by the carrier, (q 1 -q 2) /
When the value of q 0 is less than 0.4 and the change in the charge amount of the toner is very small, ⊚, when 0.4 to 0.7, ○, 0.7
A case of ˜1.0 is shown by Δ, and a case of 1.0 or more is shown by X.
Regarding the fluidity of the carrier, after copying 5,000 sheets by the above copying machine, a black solid image was copied, and the carrier was separated by 20 cm in the direction orthogonal to the paper passing direction.
The image densities at the respective points are measured by a Macbeth densitometer to measure the image density difference between the above two points, and when the image density difference is less than 0.05, it is ⊚, 0.05 to 0. The case of 1 is indicated by ◯, the case of 0.1 to 0.2 is indicated by Δ, and the case of 0.2 or more is indicated by x. Regarding the adhesion of the carrier to the image bearing member, the white spots and the background fog in the formed image, the image was visually evaluated every 1000 sheets during the printing durability test of 10,000 sheets, and the worst state was obtained. The evaluation was carried out. A level at which these were not generated at all was 5, a level at which they were slightly generated but practically not problematic, a practically lower limit level was 3,
The level at which a problem actually occurs is represented by 2, and the level at which a problem is large is represented by 1.
【００４２】[0042]
【表５】 [Table 5]
【００４３】この結果から明らかなように、キャリアの
樹脂中における磁性粉の含有量が８５〜９０重量％、磁
性粉の比表面積が８〜１２ｍ2 ／ｇ、応力−歪み特性に
おける降伏点が２０００〜３０００ｋｇ／ｃｍ2 、降伏
点における歪み量が４００〜１０００μｍ／ｃｍ、動的
電流値が３０〜１５０ｎＡ及び粒径が３０〜８０μｍの
条件を満たしている各実施例のキャリアにおいては、キ
ャリアのトナーに対する帯電性やキャリアの流動性が良
好であると共に、像担持体にキャリアが付着するという
ことも少なく、形成された画像に白ぬけや地肌かぶりや
濃度むら等が生じたりするということがなく、良好な画
像が安定して得られたのに対して、上記の条件を満たし
ていない各比較例のキャリアにおいては、キャリアのト
ナーに対する帯電性やキャリアの流動性等の何れかの点
において特性が悪くなっており、良好な画像を安定して
得ることができなかった。As is clear from these results, the content of the magnetic powder in the resin of the carrier is 85 to 90% by weight, the specific surface area of the magnetic powder is 8 to 12 m 2 / g, and the yield point in the stress-strain characteristic is 2000. ˜3000 kg / cm 2 , strain amount at yield point is 400 to 1000 μm / cm, dynamic current value is 30 to 150 nA, and particle size is 30 to 80 μm. With good chargeability and fluidity of the carrier, the carrier is less likely to adhere to the image bearing member, and there is no occurrence of white spots, background fog or density unevenness in the formed image, While good images were stably obtained, in the carrier of each comparative example that did not satisfy the above conditions, the chargeability of the carrier to the toner In some respects, such as carrier and fluidity of the carrier, the characteristics were poor, and a good image could not be stably obtained.
【００４４】[0044]
【発明の効果】以上詳述したように、この発明における
静電潜像現像用キャリアにおいては、樹脂中に磁性粉を
分散させたバインダー型のキャリアにおいて、用いる磁
性粉の比表面積や、キャリアの樹脂中における磁性粉の
含有量や、キャリアにおける応力−歪み特性の降伏点及
びこの降伏点での歪み量や、その動的電流値、さらには
その平均粒径を前記の適切な範囲になるようにしたた
め、磁性粉が樹脂中に高密度に充填されて十分な磁気力
を有すると共に、この磁性粉がキャリア中に均一に分散
されて十分に結着された状態となり、樹脂と磁性粉等と
の混練物を粉砕してキャリアを製造することも容易にな
ると共に、その粉砕時に遊離した磁性粉が発生して、キ
ャリアに付着するということも少なく、またその流動性
や抵抗値も適切にな状態になっていた。As described above in detail, in the electrostatic latent image developing carrier of the present invention, in the binder type carrier in which the magnetic powder is dispersed in the resin, the specific surface area of the magnetic powder used and the carrier The content of the magnetic powder in the resin, the yield point of the stress-strain characteristic of the carrier and the strain amount at this yield point, its dynamic current value, and its average particle size should be within the appropriate range described above. Therefore, the magnetic powder is densely packed in the resin and has a sufficient magnetic force, and the magnetic powder is uniformly dispersed in the carrier and is sufficiently bound, so that the resin and the magnetic powder are It becomes easy to pulverize the kneaded product of to produce a carrier, and the magnetic powder released during the pulverization rarely adheres to the carrier, and its fluidity and resistance value are also appropriate. It had become a state.
【００４５】この結果、この発明における静電潜像現像
用キャリアを用いて現像を行なった場合、像担持体にキ
ャリアが付着して像担持体が傷ついたり、形成された画
像にノイズが発生したりするということがなくなると共
に、遊離した磁性粉によって像担持体の電荷が消されて
画像部分に白ぬけが生じるということもなく、またトナ
ーの帯電も適切に行なわれ、形成された画像に地肌かぶ
り等が発生するということがなく、さらに現像装置内に
おける現像剤に片寄りが生じて形成された画像に濃度む
らが発生するということもなく、長期にわたって良好な
画像形成が安定して行なえるようになった。As a result, when the electrostatic latent image developing carrier according to the present invention is used for development, the carrier adheres to the image carrier to damage the image carrier, or noise is generated in the formed image. In addition, the released magnetic powder does not erase the electric charge of the image bearing member to cause white spots in the image portion, and the toner is appropriately charged, so that the formed image has a bare background. Fogging does not occur, and there is no unevenness in the density of the formed image due to the deviation of the developer in the developing device, and good image formation can be stably performed for a long period of time. It became so.
【図１】キャリアにおける動的電流値を測定する状態を
示した概略説明図である。FIG. 1 is a schematic explanatory diagram showing a state of measuring a dynamic current value in a carrier.
【図２】実施例１のキャリアにおける混練物の応力−歪
み特性を示した図である。FIG. 2 is a diagram showing stress-strain characteristics of the kneaded material in the carrier of Example 1.
【図３】実施例２のキャリアにおける混練物の応力−歪
み特性を示した図である。FIG. 3 is a diagram showing stress-strain characteristics of the kneaded material in the carrier of Example 2.
【図４】実施例３のキャリアにおける混練物の応力−歪
み特性を示した図である。FIG. 4 is a diagram showing stress-strain characteristics of the kneaded material in the carrier of Example 3.
【図５】実施例４のキャリアにおける混練物の応力−歪
み特性を示した図である。5 is a diagram showing stress-strain characteristics of the kneaded material in the carrier of Example 4. FIG.
３ キャリア 3 career
───────────────────────────────────────────────────── フロントページの続き (72)発明者 武中 浩一 大阪市中央区安土町二丁目３番13号 大阪 国際ビル ミノルタ株式会社内 (72)発明者 芝野 広志 大阪市中央区安土町二丁目３番13号 大阪 国際ビル ミノルタ株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koichi Takenaka, Kouji Takenaka 2-33-1 Azuchi-cho, Chuo-ku, Osaka, Osaka International Building Minolta Co., Ltd. (72) Hiroshi Shibano 2-3, Azuchi-cho, Chuo-ku, Osaka No. 13 Osaka International Building Minolta Co., Ltd.
Claims (1)
型の静電潜像現像用キャリアにおいて、上記磁性粉の比
表面積が８〜１２ｍ2 ／ｇの範囲にあり、樹脂中にこの
磁性粉が８５〜９０重量％含有されると共に、このキャ
リアにおける応力−歪み特性の降伏点が２０００〜３０
００ｋｇ／ｃｍ2 の範囲にありかつこの降伏点での歪み
量が４００〜１０００μｍ／ｃｍの範囲にあり、またこ
のキャリアにおける動的電流値が３０〜１５０ｎＡの範
囲で、その平均粒径が３０〜８０μｍの範囲にあること
を特徴とする静電潜像現像用キャリア。1. In a binder type electrostatic latent image developing carrier in which magnetic powder is dispersed in a resin, the specific surface area of the magnetic powder is in the range of 8 to 12 m 2 / g, and the magnetic powder is contained in the resin. Of 85 to 90% by weight, and the yield point of the stress-strain characteristic of this carrier is 2000 to 30
In the range of 00 kg / cm 2 , the strain amount at the yield point is in the range of 400 to 1000 μm / cm, the dynamic current value in the carrier is in the range of 30 to 150 nA, and the average particle size is 30 to A carrier for developing an electrostatic latent image, which is in the range of 80 μm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01861995A JP3211605B2 (en) | 1995-01-10 | 1995-01-10 | Carrier for developing electrostatic latent images |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01861995A JP3211605B2 (en) | 1995-01-10 | 1995-01-10 | Carrier for developing electrostatic latent images |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08190225A true JPH08190225A (en) | 1996-07-23 |
| JP3211605B2 JP3211605B2 (en) | 2001-09-25 |
Family
ID=11976649
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP01861995A Expired - Fee Related JP3211605B2 (en) | 1995-01-10 | 1995-01-10 | Carrier for developing electrostatic latent images |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3211605B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6306552B1 (en) | 1999-07-28 | 2001-10-23 | Minolta Co., Ltd. | Carrier having specified bet specific surface area and dynamic current value and two-component developer thereof |
-
1995
- 1995-01-10 JP JP01861995A patent/JP3211605B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6306552B1 (en) | 1999-07-28 | 2001-10-23 | Minolta Co., Ltd. | Carrier having specified bet specific surface area and dynamic current value and two-component developer thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3211605B2 (en) | 2001-09-25 |
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