JPH04326361A - Dry developer and its production - Google Patents
Dry developer and its productionInfo
- Publication number
- JPH04326361A JPH04326361A JP3122814A JP12281491A JPH04326361A JP H04326361 A JPH04326361 A JP H04326361A JP 3122814 A JP3122814 A JP 3122814A JP 12281491 A JP12281491 A JP 12281491A JP H04326361 A JPH04326361 A JP H04326361A
- Authority
- JP
- Japan
- Prior art keywords
- carrier
- toner
- magnetic powder
- developer
- binder resin
- 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
- 238000004519 manufacturing process Methods 0.000 title claims description 4
- 239000006247 magnetic powder Substances 0.000 claims abstract description 24
- 239000002245 particle Substances 0.000 claims abstract description 24
- 229920005989 resin Polymers 0.000 claims abstract description 23
- 239000011347 resin Substances 0.000 claims abstract description 23
- 239000011230 binding agent Substances 0.000 claims abstract description 20
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 10
- 238000002156 mixing Methods 0.000 claims abstract description 8
- 239000003795 chemical substances by application Substances 0.000 claims description 4
- 238000005563 spheronization Methods 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 abstract description 16
- 239000006249 magnetic particle Substances 0.000 abstract description 4
- 239000000463 material Substances 0.000 abstract description 2
- 239000012798 spherical particle Substances 0.000 abstract 1
- 239000000969 carrier Substances 0.000 description 9
- 108091008695 photoreceptors Proteins 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 239000006229 carbon black Substances 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 238000012937 correction Methods 0.000 description 2
- 238000011981 development test Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000009477 glass transition Effects 0.000 description 2
- 238000004898 kneading Methods 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 239000004640 Melamine resin Substances 0.000 description 1
- 229920000877 Melamine resin Polymers 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 1
- 229920002845 Poly(methacrylic acid) Polymers 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 229920002125 Sokalan® Polymers 0.000 description 1
- 229920001807 Urea-formaldehyde Polymers 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- MVAUZYMUXCUOQI-UHFFFAOYSA-N butyl 2-methylprop-2-enoate;2-methylprop-2-enoic acid;styrene Chemical compound CC(=C)C(O)=O.C=CC1=CC=CC=C1.CCCCOC(=O)C(C)=C MVAUZYMUXCUOQI-UHFFFAOYSA-N 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 229940090961 chromium dioxide Drugs 0.000 description 1
- IAQWMWUKBQPOIY-UHFFFAOYSA-N chromium(4+);oxygen(2-) Chemical compound [O-2].[O-2].[Cr+4] IAQWMWUKBQPOIY-UHFFFAOYSA-N 0.000 description 1
- AYTAKQFHWFYBMA-UHFFFAOYSA-N chromium(IV) oxide Inorganic materials O=[Cr]=O AYTAKQFHWFYBMA-UHFFFAOYSA-N 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000007334 copolymerization reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 1
- 229910052595 hematite Inorganic materials 0.000 description 1
- 239000011019 hematite Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229920003145 methacrylic acid copolymer Polymers 0.000 description 1
- 229940117841 methacrylic acid copolymer Drugs 0.000 description 1
- 239000000113 methacrylic resin Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229920002401 polyacrylamide Polymers 0.000 description 1
- 239000004584 polyacrylic acid Substances 0.000 description 1
- 229920002239 polyacrylonitrile Polymers 0.000 description 1
- 229920006122 polyamide resin Polymers 0.000 description 1
- 229920001083 polybutene Polymers 0.000 description 1
- 229920005668 polycarbonate resin Polymers 0.000 description 1
- 239000004431 polycarbonate resin Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 239000002952 polymeric resin Substances 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 229920005749 polyurethane resin Polymers 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 229910000859 α-Fe 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、静電潜像を現像するた
めの乾式現像剤及びその製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry developer for developing electrostatic latent images and a method for producing the same.
【0002】0002
【従来の技術】電子写真法或いは静電記録法では、現像
剤として、一般にキャリアとトナーの2成分からなる乾
式現像剤が用いられている。2成分乾式現像剤では、現
像装置内での攪拌によってキャリアとトナーとの間に摩
擦帯電を生じさせ、トナーに静電潜像と逆極性の電荷を
付与し、これを潜像に付着させて現像が行われる。従来
、この様な現像剤としては、トナーより粒径の大きなキ
ャリア(60〜500μm)が用いられているが、階調
の再現性が悪く、また、トナーのキャリアに対する割合
が増加すると、背景部へのトナー付着が生じやすいとい
う欠点があった。2. Description of the Related Art In electrophotography or electrostatic recording, a dry developer consisting of two components, a carrier and a toner, is generally used as a developer. In a two-component dry developer, frictional charging is generated between the carrier and the toner by stirring within the developing device, giving the toner a charge of opposite polarity to the electrostatic latent image, which is then attached to the latent image. Development is performed. Conventionally, carriers with larger particle sizes than toner (60 to 500 μm) have been used as such developers, but gradation reproducibility is poor and when the ratio of toner to carrier increases, background areas This has the disadvantage that toner tends to adhere to the surface.
【0003】この欠点を改善するためのものとして、磁
性微粒子を結着樹脂中に分散させた小粒径キャリア、い
わゆるマイクロトーニング用キャリアが提案され、実用
化されている。[0003] In order to improve this drawback, a small particle size carrier in which magnetic fine particles are dispersed in a binder resin, a so-called carrier for microtoning, has been proposed and put into practical use.
【0004】0004
【発明が解決しようとする課題】キャリアに対して要求
される特性は種々あるが、特に重要な特性として、適当
な帯電性、耐衝撃性、耐摩耗性、現像性、現像剤寿命等
をあげることができる。上記諸要求特性を考慮すると、
従来使用されてきたキャリアは、依然改善すべき問題を
残しており、充分に満足できるものは知られてない。例
えば、酸化鉄粉をはじめとする導電性キャリアはソリッ
ド現像性には優れているものの、細線現像性に劣り、ま
た、寿命延長のために、特殊な帯電制御剤をトナーに含
有させることを必要とする等の欠点を有しており、一方
、コート系の絶縁性キャリアは、寿命、細線の再現性な
どには優れているものの、ソリッド再現性に劣るという
欠点を有している。また、マイクロトーニング用キャリ
アは、キャリア及び表面に遊離した磁性体粒子の感光体
への付着、表面に遊離した磁性体粒子に起因する高湿、
低湿時の帯電量の変化、表面処理が困難なことによる抜
本的寿命の延長が不可能であること等の不都合を有する
。したがって、本発明の目的は、従来の技術における上
記の問題点、特に小粒径キャリアにおける従来の欠点を
解消し、キャリアより表面に遊離した磁性体粒子が、感
光体に付着しにくい現像剤を提供することにある。[Problems to be Solved by the Invention] There are various properties required of carriers, but particularly important properties include appropriate charging properties, impact resistance, abrasion resistance, developability, and developer life. be able to. Considering the above required characteristics,
Conventionally used carriers still have problems to be improved, and no fully satisfactory carriers are known. For example, conductive carriers such as iron oxide powder have excellent solid developability, but are inferior in fine line developability, and in order to extend the life of the toner, it is necessary to include a special charge control agent in the toner. On the other hand, coat-based insulating carriers have the disadvantage of being poor in solid reproducibility, although they are excellent in longevity and fine wire reproducibility. In addition, carriers for microtoning are susceptible to problems such as adhesion of magnetic particles released on the carrier and surface to the photoreceptor, high humidity caused by magnetic particles released on the surface, etc.
It has disadvantages such as changes in the amount of charge at low humidity and difficulty in surface treatment, which makes it impossible to dramatically extend the lifespan. Therefore, it is an object of the present invention to solve the above-mentioned problems in the conventional technology, particularly in the case of small particle carriers, and to create a developer in which the magnetic particles liberated on the surface of the carrier are less likely to adhere to the photoreceptor. It is about providing.
【0005】[0005]
【課題を解決するための手段】本発明者等は、結着樹脂
及び磁性粉を含有するキャリアを、球形化を目的として
加熱処理する温度より低い温度で加熱することによって
、上記の目的が達成されることを見出し、本発明を完成
するに至った。[Means for Solving the Problems] The present inventors have achieved the above object by heating a carrier containing a binder resin and magnetic powder at a temperature lower than the temperature at which heat treatment is performed for the purpose of spheroidization. The present inventors have discovered that the present invention is possible and have completed the present invention.
【0006】本発明は、結着樹脂及び磁性粉を含有する
キャリアとトナーとからなる乾式現像剤において、キャ
リアが球形化処理温度よりも低い温度で加熱処理された
粒子であることを特徴とする。本発明の乾式現像剤は、
結着樹脂及び磁性粉を含有するキャリアを、球形化処理
温度よりも低い温度で加熱処理した後、トナーと混合す
ることによって製造することができる。[0006] The present invention provides a dry developer comprising a toner and a carrier containing a binder resin and magnetic powder, characterized in that the carrier is particles heat-treated at a temperature lower than the spheronization temperature. . The dry developer of the present invention is
It can be produced by heating a carrier containing a binder resin and magnetic powder at a temperature lower than the spheroidization temperature and then mixing it with a toner.
【0007】以下、本発明を詳細に説明する。本発明に
おいて使用するキャリアの結着樹脂としては、ポリスチ
レン、ポリエチレン、ポリプロピレン、ポリブテン、ア
クリル樹脂、メタクリル樹脂、ポリアクリロニトリル、
ポリアクリルアミド、ポリアクリル酸、ポリメタクリル
酸、酢酸ビニル樹脂、塩化ビニル樹脂等の付加重合型樹
脂、フェノール樹脂、尿素樹脂、メラミン樹脂、ポリエ
ステル樹脂、ポリカーボネート樹脂、ポリアミド樹脂、
ポリウレタン樹脂、エポキシ樹脂等の縮合型樹脂及びそ
れらモノマーの共重合体をあげることができる。The present invention will be explained in detail below. Examples of the binder resin for the carrier used in the present invention include polystyrene, polyethylene, polypropylene, polybutene, acrylic resin, methacrylic resin, polyacrylonitrile,
Addition polymer resins such as polyacrylamide, polyacrylic acid, polymethacrylic acid, vinyl acetate resin, vinyl chloride resin, phenol resin, urea resin, melamine resin, polyester resin, polycarbonate resin, polyamide resin,
Examples include condensation type resins such as polyurethane resins and epoxy resins, and copolymers of these monomers.
【0008】本発明において使用するキャリアの磁性粉
としては、平均粒径0.1〜3μmのものを用いるもの
が好ましい。磁性粉としてマグネタイト、フェライト、
鉄、ニッケル、二酸化クロム、γ−ヘマタイト、コバル
トなどの微粉末を使用することができる。中でも安価で
かつ安定して使用できるものとして、マグネタイトが好
ましい。本発明で使用する磁性粉は、含有量が磁性キャ
リアの飽和磁束密度に多大な影響を及ぼすので注意を要
する。The carrier magnetic powder used in the present invention preferably has an average particle size of 0.1 to 3 μm. Magnetite, ferrite, as magnetic powder
Fine powders of iron, nickel, chromium dioxide, γ-hematite, cobalt, etc. can be used. Among them, magnetite is preferred because it is inexpensive and can be used stably. The content of the magnetic powder used in the present invention has a great effect on the saturation magnetic flux density of the magnetic carrier, so care must be taken.
【0009】キャリア中の結着樹脂と磁性粉の配合比は
、重量比で20:80〜70:30、好ましくは20:
80〜50:50が適当である。磁性粉の含有量が80
重量%を越えると、結着能が劣ることになり、キャリア
粒子が脆くなったり、キャリアの製造が困難になったり
する。一方、30重量%未満では、十分な磁性が得られ
ず、搬送性が悪化する。本発明において、キャリアには
、その他必要に応じて導電性調節剤としてのカーボンブ
ラック、帯電制御剤等を添加してもよい。[0009] The blending ratio of the binder resin and magnetic powder in the carrier is 20:80 to 70:30 by weight, preferably 20:
A ratio of 80:50 to 50:50 is appropriate. Magnetic powder content is 80
If the amount exceeds % by weight, the binding ability will be poor, the carrier particles will become brittle, and the manufacture of the carrier will become difficult. On the other hand, if it is less than 30% by weight, sufficient magnetism cannot be obtained and transportability deteriorates. In the present invention, carbon black as a conductivity regulator, a charge control agent, etc. may be added to the carrier as necessary.
【0010】本発明のキャリアの重量平均粒径は、小粒
径キャリアの場合は、10〜50μm、好ましくは20
〜40μmの範囲が適当である。重量平均粒径が10μ
m未満では、背景部へのキャリア付着が生じ、50μm
を越えると、画像の鮮明さが失われ、画質が低下するか
らである。また、小粒径としない場合には、50〜15
0μmの範囲のものが用いられる。その場合には、トナ
ー濃度を小粒径キャリアの場合よりも低くすればよい。[0010] The weight average particle size of the carrier of the present invention is 10 to 50 μm, preferably 20 μm in the case of a small particle size carrier.
A range of ~40 μm is suitable. Weight average particle size is 10μ
If the diameter is less than 50 μm, carrier adhesion to the background will occur, and if the diameter is less than 50 μm,
This is because, if it exceeds this, the sharpness of the image will be lost and the image quality will deteriorate. In addition, if the particle size is not small, 50 to 15
A material in the range of 0 μm is used. In that case, the toner concentration may be lower than in the case of small particle size carriers.
【0011】本発明のキャリアは、結着樹脂と磁性粉を
溶融混練した後、粉砕する方法、溶剤に溶かした結着樹
脂溶液に磁性粉を分散させ、加熱噴霧するスプレードラ
イ法、或いは磁性粉の存在下で結着樹脂のモノマーを直
接重合する方法等によってキャリア粒子を作成した後、
球形化処理温度以下、すなわち結着樹脂の融点以下の温
度、好ましくは、結着樹脂のガラス転移点付近の温度に
おいて加熱処理することによって製造することができる
。[0011] The carrier of the present invention can be prepared by a method in which a binder resin and magnetic powder are melt-kneaded and then pulverized, a spray-dry method in which magnetic powder is dispersed in a binder resin solution dissolved in a solvent and heated and sprayed, or a method in which magnetic powder is melt-kneaded and then crushed. After creating carrier particles by direct polymerization of binder resin monomers in the presence of
It can be produced by heat treatment at a temperature below the spheroidization treatment temperature, that is, below the melting point of the binder resin, preferably at a temperature around the glass transition point of the binder resin.
【0012】キャリアの加熱処理は、従来混練粉砕法で
得た非球形キャリアを、その結着樹脂の融点付近の温度
で加熱処理する、いわゆる球形化のための熱処理と同様
な方法で行うことができるが、本発明においては、従来
の球状化のための熱処理とは異なり、結着樹脂の融点よ
りも低い温度、好ましくはガラス転移点付近の温度で加
熱する。このような熱処理を施すことにより、キャリア
の粒子表面に遊離している磁性粉は、結着樹脂により覆
われるか、又はキャリア表面に結着され、感光体への付
着が生じなくなる。加熱温度が、融点よりも高い温度で
行われると、キャリア粒子の表面に露出している磁性粉
が結着樹脂により完全に被覆され、トナーとの電荷交換
性が劣り、十分な帯電性を維持できなくなる。加熱処理
のための加熱手段としては、例えば乾燥機、熱風流動層
、高周波加熱器き等が用いられる。[0012] The heat treatment of the carrier can be carried out in the same manner as the so-called heat treatment for spheroidization, in which a non-spherical carrier obtained by conventional kneading and pulverization is heat-treated at a temperature near the melting point of its binder resin. However, in the present invention, unlike conventional heat treatment for spheroidization, heating is performed at a temperature lower than the melting point of the binder resin, preferably at a temperature near the glass transition point. By performing such heat treatment, the magnetic powder free on the surface of the particles of the carrier is covered with the binder resin or is bound to the surface of the carrier, and no longer adheres to the photoreceptor. If the heating temperature is higher than the melting point, the magnetic powder exposed on the surface of the carrier particles will be completely covered with the binder resin, and the charge exchangeability with the toner will be poor, maintaining sufficient chargeability. become unable. As a heating means for the heat treatment, for example, a dryer, a hot air fluidized bed, a high frequency heater, etc. are used.
【0013】本発明においては、上記の加熱処理は、キ
ャリアの粒子表面における磁性粉の露出量が、鉄元素と
して1.0〜2.0原子%になるように行なうのが好ま
しい。それにより、感光体への遊離磁性粉の付着がなく
なり、かつ帯電維持性の高い現像剤が得られる。In the present invention, the above heat treatment is preferably carried out so that the amount of magnetic powder exposed on the carrier particle surface is 1.0 to 2.0 atomic % as iron element. As a result, adhesion of free magnetic powder to the photoreceptor is eliminated, and a developer with high charge retention properties can be obtained.
【0014】本発明において、磁性粉の露出量は、次の
ようにして測定される。
測定装置:日本電子(株)製、X線光電子分光装置JP
S−80
測定条件:
X線:Mg/Alツインアノード型
Mg1253.6eV使用
加速10KV、30mA
アナライザー分解能: 30eV
対象光電子:
Fe 2p3/2
O 1s
C 1s
結合エネルギー
Fe 726〜706eV
O 542〜527eV
C 294〜279eV
0.2eV ステップ:
Fe 500ms/ステップ
O 200ms/ステップ
C 20ms/ステップのデータ取り込み積
算:30回
ピーク面積算出:直線のバックグラウンドを設定し、面
積を原子数とし、
面積/(取り込み時間/ステップ)/補正因子但し、補
正因子としてFe:6.14、O:2.28、C:1.
00
Fe+O+C=100として、それぞれの原子数の%を
算出する。
サンプリング方法:15mm×10mm×2mmのAl
容器にトナーを充填し、平らにならす。In the present invention, the amount of exposed magnetic powder is measured as follows. Measuring device: X-ray photoelectron spectrometer JP manufactured by JEOL Ltd.
S-80 Measurement conditions: X-ray: Mg/Al twin anode type Mg1253.6eV acceleration 10KV, 30mA Analyzer resolution: 30eV Target photoelectrons: Fe 2p3/2 O 1s C 1s Binding energy Fe 726-706eV O 542-527eV C 294 ~279eV 0.2eV Step: Fe 500ms/step O 200ms/step C 20ms/step data acquisition Integration: 30 times Peak area calculation: Set the straight background, take the area as the number of atoms, and calculate the area/(intake time/ step)/correction factor However, the correction factors are Fe: 6.14, O: 2.28, C: 1.
00 Fe+O+C=100, calculate the percentage of each number of atoms. Sampling method: 15mm x 10mm x 2mm Al
Fill the container with toner and level it out.
【0015】本発明の現像剤に使用されるトナーは、結
着樹脂、着色剤及び必要に応じて帯電制御剤からなる。
トナーの平均粒径は5〜20μmが好ましい。The toner used in the developer of the present invention comprises a binder resin, a colorant and, if necessary, a charge control agent. The average particle size of the toner is preferably 5 to 20 μm.
【0016】本発明の現像剤は、加熱処理されたキャリ
アとトナーとを混合して調製される。トナーとキャリア
との配合比は、重量比で2:98〜30:70、好まし
くは5:95〜15:85の範囲が適当である。これは
。トナーが2重量%未満では、画像濃度が不十分であり
、また、30重量%を超えると、トナーの飛散及びトナ
ーの背景部付着が発生するからである。The developer of the present invention is prepared by mixing a heat-treated carrier and a toner. The mixing ratio of toner and carrier is suitably in the range of 2:98 to 30:70, preferably 5:95 to 15:85 in terms of weight ratio. this is. If the toner content is less than 2% by weight, the image density will be insufficient, and if it exceeds 30% by weight, toner scattering and toner adhesion to the background will occur.
【0017】[0017]
【実施例】以下、本発明を実施例及び比較例をあげて説
明する。
実施例1
スチレン−n−ブチルメタクリレート−メタクリル
酸共重合体 30重量部 (スチ
レン80重量%、メタクリル酸5重量%、
Mw=80,000、Tg=90℃) マグ
ネタイト
70重量部上記成分を溶融混練した後、微粉砕し、
分級を行ない、平均粒径34.5μmのキャリアを得た
。得られたキャリアを流動層型乾燥機に仕込み、流動層
内部を80℃になるように制御し、約30分間加熱処理
を行なった。加熱処理後、室温まで冷却した後、キャリ
アを取り出した。[Examples] The present invention will be explained below with reference to Examples and Comparative Examples. Example 1 Styrene-n-butyl methacrylate-methacrylic acid copolymer 30 parts by weight (80% by weight of styrene, 5% by weight of methacrylic acid,
Mw=80,000, Tg=90℃) Magnetite
70 parts by weight After melt-kneading the above ingredients, finely pulverize,
Classification was performed to obtain a carrier having an average particle size of 34.5 μm. The obtained carrier was placed in a fluidized bed dryer, the temperature inside the fluidized bed was controlled to 80° C., and heat treatment was performed for about 30 minutes. After the heat treatment and cooling to room temperature, the carrier was taken out.
【0018】上記キャリアとは別に、トナーとして
スチレン−n− ブチルメタクリレート−ジメチルアミ
ノ 94重量部
メタクリレート共重合体(共重合比65:30:5;
Mw=50,000)
カーボンブラック
6重量部上記成分を溶融混練した後
、微粉砕して、平均粒径10.5μmのトナーを得た。
前記キャリア92重量部、トナー8重量部をVブレンダ
ーにて混合し、現像剤を調製した。[0018] Apart from the above carrier, as a toner
Styrene-n-butyl methacrylate-dimethylamino 94 parts by weight
Methacrylate copolymer (copolymerization ratio 65:30:5;
Mw=50,000)
Carbon black
6 parts by weight of the above components were melted and kneaded and then finely pulverized to obtain a toner having an average particle size of 10.5 μm. 92 parts by weight of the carrier and 8 parts by weight of the toner were mixed in a V blender to prepare a developer.
【0019】実施例2
流動層内部を90℃とすること以外は、実施例1と同様
にしてキャリアを得、実施例1と同様のトナーと同じ割
合で混合して現像剤を得た。Example 2 A carrier was obtained in the same manner as in Example 1, except that the temperature inside the fluidized bed was kept at 90° C., and a developer was obtained by mixing the carrier with the same toner as in Example 1 in the same ratio.
【0020】比較例1
流動層内部を100℃とすること以外は、実施例1と同
様にしてキャリアを得、実施例1と同様のトナーと同じ
割合で混合して現像剤を得た。Comparative Example 1 A carrier was obtained in the same manner as in Example 1, except that the temperature inside the fluidized bed was set at 100° C., and a developer was obtained by mixing it with the same toner as in Example 1 in the same ratio.
【0021】比較例2
キャリアを加熱処理しないこと以外は、実施例1と同様
にしてキャリアを得、実施例1と同様のトナーと同じ割
合で混合して現像剤を得た。Comparative Example 2 A carrier was obtained in the same manner as in Example 1, except that the carrier was not heat-treated, and was mixed with the same toner as in Example 1 in the same ratio to obtain a developer.
【0022】現像試験
上記実施例および比較例で得られた現像剤について現像
試験を行なった。即ち、現像剤撹拌装置を備えた磁気ブ
ラシ現像装置を用い、各現像剤について、負極性静電潜
像を連続して現像し、画質の維持性を観察した。その結
果を表1に示す。Development Test A development test was conducted on the developers obtained in the above Examples and Comparative Examples. That is, a negative electrostatic latent image was continuously developed for each developer using a magnetic brush developing device equipped with a developer stirring device, and the maintenance of image quality was observed. The results are shown in Table 1.
【0023】[0023]
【表1】[Table 1]
【0024】比較例2における背景部かぶりについて、
感光体上からかぶり粒子を採取し、分析したところ、そ
の殆どが磁性を有しており、その粒径から、磁性粉であ
ることが判明した。上記の結果より、本発明における現
像剤を用いると、背景部へのカブリがなく、鮮明な、特
に階調性に優れた画質の画像が得られ、また20万枚複
写しても、何等問題なく、優れた画質が維持されること
が確認された。Regarding background fog in Comparative Example 2,
When fog particles were collected from the photoreceptor and analyzed, most of them were found to be magnetic, and based on their particle size, they were found to be magnetic powder. From the above results, it is clear that when the developer of the present invention is used, there is no fogging in the background, clear images with particularly excellent gradation quality can be obtained, and even when 200,000 copies are made, there are no problems. It was confirmed that excellent image quality was maintained.
【0025】[0025]
【発明の効果】本発明の乾式現像剤は、上記のようにキ
ャリアが球形化処理温度よりも低い温度で加熱処理され
ているから、キャリア及び遊離磁性粉の感光体への付着
を防ぎ、長時間の使用に耐えることができる。したがっ
て、本発明による乾式現像剤を使用すると、解像力、階
調性に優れた、良好な画質の画像を長期にわたって得る
ことができる。Effects of the Invention: In the dry developer of the present invention, since the carrier is heat-treated at a temperature lower than the spheroidization temperature, it prevents the carrier and free magnetic powder from adhering to the photoreceptor, and can be used for a long time. Can withstand the use of time. Therefore, when the dry developer according to the present invention is used, images of good quality and excellent resolution and gradation can be obtained for a long period of time.
Claims (3)
アとトナーとからなる乾式現像剤において、キャリアが
球形化処理温度よりも低い温度で加熱処理された粒子で
あることを特徴とする乾式現像剤。1. A dry developer comprising a toner and a carrier containing a binder resin and magnetic powder, characterized in that the carrier is particles heat-treated at a temperature lower than the spheronization temperature. agent.
露出量が、鉄元素として1.0〜2.0原子%であるこ
とを特徴とする請求項1に記載の乾式現像剤。2. The dry developer according to claim 1, wherein the amount of magnetic powder exposed on the surface of the carrier particles is 1.0 to 2.0 at % as iron element.
アを、球形化処理温度よりも低い温度で加熱処理した後
、トナーと混合することを特徴とする乾式現像剤の製造
方法。3. A method for producing a dry developer, which comprises heat-treating a carrier containing a binder resin and magnetic powder at a temperature lower than a spheroidization temperature, and then mixing the carrier with a toner.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3122814A JPH04326361A (en) | 1991-04-26 | 1991-04-26 | Dry developer and its production |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3122814A JPH04326361A (en) | 1991-04-26 | 1991-04-26 | Dry developer and its production |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH04326361A true JPH04326361A (en) | 1992-11-16 |
Family
ID=14845300
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3122814A Pending JPH04326361A (en) | 1991-04-26 | 1991-04-26 | Dry developer and its production |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH04326361A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2012032769A (en) * | 2010-07-06 | 2012-02-16 | Ricoh Co Ltd | Method for manufacturing electrophotographic carrier, carrier, developer, developer for replenishment and process cartridge |
JP2012173471A (en) * | 2011-02-21 | 2012-09-10 | Ricoh Co Ltd | Production method of electrophotographic carrier |
JP2012220864A (en) * | 2011-04-13 | 2012-11-12 | Ricoh Co Ltd | Method for manufacturing electrophotographic carrier |
-
1991
- 1991-04-26 JP JP3122814A patent/JPH04326361A/en active Pending
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2012032769A (en) * | 2010-07-06 | 2012-02-16 | Ricoh Co Ltd | Method for manufacturing electrophotographic carrier, carrier, developer, developer for replenishment and process cartridge |
JP2012173471A (en) * | 2011-02-21 | 2012-09-10 | Ricoh Co Ltd | Production method of electrophotographic carrier |
JP2012220864A (en) * | 2011-04-13 | 2012-11-12 | Ricoh Co Ltd | Method for manufacturing electrophotographic carrier |
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