JP2763426B2 - Magnetic developer - Google Patents
Magnetic developerInfo
- Publication number
- JP2763426B2 JP2763426B2 JP3257386A JP25738691A JP2763426B2 JP 2763426 B2 JP2763426 B2 JP 2763426B2 JP 3257386 A JP3257386 A JP 3257386A JP 25738691 A JP25738691 A JP 25738691A JP 2763426 B2 JP2763426 B2 JP 2763426B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- weight
- developer
- charge control
- control agent
- 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.)
- Expired - Fee Related
Links
- 230000005291 magnetic effect Effects 0.000 title claims description 72
- 239000003795 chemical substances by application Substances 0.000 claims description 30
- 239000006247 magnetic powder Substances 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 12
- 229920005989 resin Polymers 0.000 claims description 7
- 239000011347 resin Substances 0.000 claims description 7
- 239000011230 binding agent Substances 0.000 claims description 3
- 239000000696 magnetic material Substances 0.000 claims description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- 239000000203 mixture Substances 0.000 description 4
- 239000000654 additive Substances 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 108091008695 photoreceptors Proteins 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 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
- 229910018605 Ni—Zn Inorganic materials 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 239000000987 azo dye Substances 0.000 description 2
- 239000000969 carrier Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000000975 dye Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 230000002209 hydrophobic effect Effects 0.000 description 2
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910002012 Aerosil® Inorganic materials 0.000 description 1
- 229910017518 Cu Zn Inorganic materials 0.000 description 1
- 229910017752 Cu-Zn Inorganic materials 0.000 description 1
- 229910017943 Cu—Zn Inorganic materials 0.000 description 1
- 229930182556 Polyacetal Natural products 0.000 description 1
- 229910001035 Soft ferrite Inorganic materials 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 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
- 239000006229 carbon black Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- TVZPLCNGKSPOJA-UHFFFAOYSA-N copper zinc Chemical compound [Cu].[Zn] TVZPLCNGKSPOJA-UHFFFAOYSA-N 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000005294 ferromagnetic effect Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- YLGXILFCIXHCMC-JHGZEJCSSA-N methyl cellulose Chemical compound COC1C(OC)C(OC)C(COC)O[C@H]1O[C@H]1C(OC)C(OC)C(OC)OC1COC YLGXILFCIXHCMC-JHGZEJCSSA-N 0.000 description 1
- 239000003607 modifier Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000002093 peripheral effect Effects 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
- 229920000098 polyolefin Polymers 0.000 description 1
- 229920006324 polyoxymethylene Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 229920001909 styrene-acrylic polymer Polymers 0.000 description 1
Landscapes
- Developing Agents For Electrophotography (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は画像担体表面に形成した
静電荷像を磁気ブラシ法によって現像する際に使用す
る、磁性トナーと磁性キャリアとを混合してなる磁性現
像剤に関するものであり、特に摩擦帯電特性が高く、か
つ連続現像時における画像濃度の安定化が可能である磁
性現像剤に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic developer comprising a mixture of a magnetic toner and a magnetic carrier, which is used for developing an electrostatic image formed on the surface of an image carrier by a magnetic brush method. In particular, the present invention relates to a magnetic developer having high triboelectric charging characteristics and capable of stabilizing the image density during continuous development.
【０００２】[0002]
【従来の技術】画像担体表面に形成した静電荷像を現像
する場合には、一般に磁気ブラシ法が使用されている。
而して磁気ブラシ現像に使用される現像剤としては、磁
性キャリアと非磁性トナーとを混合した二成分系現像剤
が多い。一方現像剤として樹脂と磁性粉による一成分系
現像剤を使用する方法もある。前者の二成分系現像剤を
使用する方法においては、画像濃度および解像度の良好
な画像が得られる反面、中間調の再現性が劣るという問
題点がある。2. Description of the Related Art In developing an electrostatic charge image formed on the surface of an image carrier, a magnetic brush method is generally used.
As a developer used for magnetic brush development, there are many two-component developers in which a magnetic carrier and a non-magnetic toner are mixed. On the other hand, there is a method of using a one-component developer composed of a resin and magnetic powder as a developer. In the former method using a two-component developer, although an image having good image density and resolution can be obtained, there is a problem that the reproducibility of halftone is inferior.
【０００３】一方後者の一成分系現像剤を使用する方法
においては、トナー帯電量の増加に伴うトナーの帯電凝
集現像の惹起、スリーブ上のトナー不足による現像不足
等の問題点がある。これらの問題点を解決する手段とし
て、例えば特開昭59−162563号および同59−216149号公
報に記載のような磁性キャリアと磁性トナーとを混合し
た現像剤が提案されており、前記従来の二成分系現像剤
および一成分系現像剤の両者の長所を併有するものとさ
れている。On the other hand, the latter method using a one-component developer has problems such as the occurrence of charge aggregation development of the toner due to an increase in the toner charge amount, and insufficient development due to a shortage of the toner on the sleeve. As means for solving these problems, for example, a developer in which a magnetic carrier and a magnetic toner are mixed as described in JP-A-59-162563 and JP-A-59-216149 has been proposed. It has both advantages of a two-component developer and a one-component developer.
【０００４】[0004]
【発明が解決しようとする課題】上記のような磁性キャ
リアと磁性トナーとを混合した現像剤を使用する静電荷
像の現像方法においては、二成分系および一成分系の各
現像剤を使用する方法の各長所を併有する一方におい
て、磁性トナーの保磁力が低い場合、若しくは磁性トナ
ー中の磁性粉の含有量が少ない場合には、画像が不鮮明
となる問題点がある。すなわち、画像担体表面に対向し
て配置し、かつ内部に永久磁石等の磁界発生部材を備え
た非磁性スリーブによる現像剤の搬送性が低いため、磁
気ブラシの画像担体表面の摺擦により消費される磁性ト
ナーの補給が不足し、磁性キャリア濃度が高くなるため
である。In the above-described method of developing an electrostatic image using a developer in which a magnetic carrier and a magnetic toner are mixed, a two-component developer and a one-component developer are used. While having the advantages of each method, when the coercive force of the magnetic toner is low, or when the content of the magnetic powder in the magnetic toner is small, there is a problem that an image becomes unclear. In other words, since the non-magnetic sleeve provided with a magnetic field generating member such as a permanent magnet inside has a low transportability of the developer disposed opposite to the image carrier surface, the magnetic brush is consumed by rubbing of the image carrier surface. This is because the replenishment of the magnetic toner becomes insufficient and the concentration of the magnetic carrier increases.
【０００５】この問題点を解消するために、単に現像剤
供給手段であるスリーブ若しくは磁界発生部材の回転数
を増大することは、騒音発生等事務環境を著しく悪化さ
せるため不都合であり、一方スリーブ若しくは磁界発生
部材の外径を大にすることは、近年の現像装置に対する
小型化、薄型化若しくは軽量化等の要請に反するため採
用できない。In order to solve this problem, simply increasing the rotation speed of the sleeve or the magnetic field generating member as the developer supply means is disadvantageous because it significantly deteriorates the office environment such as noise generation. Increasing the outer diameter of the magnetic field generating member cannot be adopted because it contradicts recent demands for developing devices to be smaller, thinner, or lighter.
【０００６】また磁性現像剤を構成する磁性トナーは、
充分な荷電性を付与するため、すなわち荷電制御の目的
でニグロシン染料若しくは含金属アゾ染料等の荷電制御
剤を含有している。このような荷電制御剤を含有させる
ことにより、磁性現像剤の帯電性を向上させることがで
き、画像濃度を向上できるのである。すなわち、磁気搬
送手段による現像領域までの間においては磁性トナーは
磁気吸引力によって磁性キャリアの表面に保持されてい
るものであるから、磁性トナーの帯電性を向上させるこ
とにより、現像領域における静電気力による感光体への
付着力が増大し、画像濃度を向上させ得るのである。The magnetic toner constituting the magnetic developer includes:
It contains a charge control agent such as a nigrosine dye or a metal-containing azo dye for imparting sufficient chargeability, that is, for the purpose of charge control. By including such a charge control agent, the chargeability of the magnetic developer can be improved, and the image density can be improved. That is, since the magnetic toner is held on the surface of the magnetic carrier by the magnetic attraction force until the developing area by the magnetic transport means, by improving the chargeability of the magnetic toner, the electrostatic force in the developing area is improved. This increases the adhesive force to the photoreceptor, thereby improving the image density.
【０００７】この点、前記従来の二成分系現像剤におい
ては、磁性キャリアと非磁性トナーとの保持は静電気力
のみであるから、非磁性トナーの帯電性を増大させるこ
とは、現像領域における磁性キャリアと非磁性トナーの
付着力を増大させる結果を招来し、却って画像濃度を低
下させることと相違するのである。In this respect, in the above-described conventional two-component developer, the magnetic carrier and the non-magnetic toner are held only by the electrostatic force. This results in an increase in the adhesive force between the carrier and the non-magnetic toner, which is different from reducing the image density.
【０００８】上記のように磁性トナーの帯電性を向上さ
せるためには、荷電制御剤を含有させることが有効であ
るが、この荷電制御剤は磁性トナーを構成する結着用樹
脂との相溶性が低く、分散性が悪いため添加量に限界が
あり、必要とする帯電性を確保するのが困難であるとい
う問題点がある。このため現像装置始動直後においては
帯電性が低く、所定の帯電性を具有するまでの時間が長
いと共に、連続現像時において画像濃度が低下するとい
う問題点もある。In order to improve the chargeability of the magnetic toner as described above, it is effective to include a charge control agent. However, the charge control agent has a compatibility with a binder resin constituting the magnetic toner. However, there is a problem in that the addition amount is limited due to low dispersibility, and it is difficult to secure required chargeability. For this reason, there is a problem that the chargeability is low immediately after the start of the developing device, a long time is required to have a predetermined chargeability, and the image density is reduced during continuous development.
【０００９】本発明は上記従来技術に存在する問題点を
解決し、帯電性が高いと共に、連続現像時においても画
像濃度の安定化が可能である磁性現像剤を提供すること
を目的とする。SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic developer which solves the above-mentioned problems in the prior art and has high chargeability and can stabilize the image density even during continuous development.
【００１０】[0010]
【課題を解決するための手段】上記目的を達成するため
に、本発明においては、非磁性材料からなるスリーブと
永久磁石部材とを共に回転させてスリーブ上に保持した
現像剤をスリーブと同方向に搬送する磁気ブラシ現像法
に使用する、少なくとも結着樹脂、磁性粉および負帯電
性染料からなる荷電制御剤を含有する磁性トナーと磁性
キャリアとを混合してなる磁性現像剤において、磁性粉
の含有量を４０〜７５重量％とし、荷電制御剤の含有量
を 0.5〜５重量％とすると共に、磁性トナー１００重量
部に対して前記荷電制御剤と同極性でかつ体積固有抵抗
の差が１０ 2 Ω・cm以下である荷電制御剤を0.05〜１重
量部外添する、という技術的手段を採用した。According to the present invention, there is provided a sleeve made of a non-magnetic material.
Rotated together with permanent magnet member and held on sleeve
Magnetic brush development method for transporting developer in the same direction as the sleeve
At least binder resin, magnetic powder and negative charge
In a magnetic developer obtained by mixing a magnetic toner and a magnetic carrier containing a charge control agent composed of a dye , the content of the magnetic powder is set to 40 to 75% by weight, and the content of the charge control agent is set to 0.5 to 5% by weight. % And the same polarity as the charge control agent and the volume resistivity relative to 100 parts by weight of the magnetic toner.
The technical means of adding 0.05 to 1 part by weight of a charge control agent having a difference of 10 2 Ω · cm or less was employed.
【００１１】本発明において、内添する荷電制御剤と外
添する荷電制御剤とは同一種類若しくは同一仕様である
ことが好ましいが、体積固有抵抗の差が１０2 Ω・cm以
下であれば同等の特性を発揮できる。In the present invention, the charge control agent to be internally added and the charge control agent to be externally added are preferably of the same type or of the same specification. However, if the difference in the volume specific resistance is 10 2 Ω · cm or less, they are equivalent. The characteristics of can be exhibited.
【００１２】本発明において、体積固有抵抗は、サンプ
ルを約１０数mg計り取り、ダイアルゲージを改良した内
径3.05mm（断面積 0.073mm2 ）のポリアセタール製絶縁
シリンダ中に充填し、 0.1kg重の荷重下で、Ｄ．Ｃ．40
00Ｖ／cmの電場で抵抗を測定し（横河ヒューレットパッ
カード製4329Ａ型絶縁抵抗計を使用）、算出したもので
ある。In the present invention, the volume resistivity is measured by measuring about 10 mg or more of a sample, filling a polyacetal insulated cylinder having an inner diameter of 3.05 mm (cross-sectional area of 0.073 mm 2 ) with an improved dial gauge and 0.1 kg weight. Under load, C. 40
The resistance was measured in an electric field of 00 V / cm (using a 4329A insulation resistance meter manufactured by Yokogawa Hewlett-Packard) and calculated.
【００１３】また本発明においては、具体的には、例え
ばボントロンＥ８１（オリエント化学製 体積固有抵抗
１×１０15Ω・cm）、ボントロンＥ８４（同８×１０14
Ω・cm）、バリファスト3/20（同９×１０14Ω・cm）お
よびカヤチャージＴ２（日本化薬製 体積固有抵抗４×
１０14Ω・cm）の１種若しくは２種以上の組合わせ、ま
たはカヤチャージＴ２（前記参照）とボントロンＳ３４
（オリエント化学製体積固有抵抗５×１０12Ω・cm）の
組合わせで市販の荷電制御剤を使用すればよい。In the present invention, more specifically, for example, Bontron E81 (volume specific resistance 1 × 10 15 Ω · cm manufactured by Orient Chemical), Bontron E84 (8 × 10 14)
Ω · cm), VARIFAST 3/20 (9 × 10 14 Ω · cm) and Kayacharge T2 ( Nippon Kayaku volume resistivity 4 ×)
10 14 Ω · cm) or a combination of Kayacharge T2 (see above) and Bontron S34
(Orient Chemical's volume resistivity 5 × 10 12 Ω · cm) may be used in combination with a commercially available charge control agent.
【００１４】本発明において、磁性トナーに外添する荷
電制御剤が0.05重量部未満では帯電性の向上が期待でき
ず、また画像のキレが改善できないため好ましくない。
一方１重量部を超えると汚れ等を発生するため不都合で
ある。In the present invention, if the amount of the charge control agent externally added to the magnetic toner is less than 0.05 part by weight, improvement in chargeability cannot be expected, and image sharpness cannot be improved.
On the other hand, if it exceeds 1 part by weight, dirt and the like are generated, which is inconvenient.
【００１５】なお荷電制御剤を磁性トナーに外添する手
段としては、機械的な混合によるものの他に，加熱した
磁性トナーの表面に荷電制御剤を付着させてもよく、ま
た荷電制御剤を予め溶剤を介して溶解させた後、磁性ト
ナーにまぶすようにしてもよい。またこの荷電制御剤と
共に、シリカ、アルミナ、チタニア等の酸化物微粒子を
外添させてもよい。As a means for externally adding the charge control agent to the magnetic toner, a charge control agent may be adhered to the surface of the heated magnetic toner in addition to a mechanical mixing method. After dissolving via a solvent, the toner may be dusted. Further, oxide fine particles such as silica, alumina and titania may be externally added together with the charge control agent.
【００１６】また、本発明に用いる磁性トナーは、定着
用樹脂と磁性粉と、必要に応じ種々の添加物（荷電制御
剤、抵抗調節剤、流動性改質剤等）を加えて、調整され
る。上記定着用樹脂は、定着方式に応じて適宜選定すれ
ばよい（例えば特開昭57−97545 号公報参照）。一例と
して熱ロール定着方式の場合には、スチレン・アクリル
系共重合体、スチレン・ブタジェン共重合体、ポリエス
テル樹脂、エポキシ樹脂及びそれらの混合樹脂が挙げら
れる。The magnetic toner used in the present invention is prepared by adding a fixing resin, a magnetic powder, and various additives (a charge controlling agent, a resistance controlling agent, a fluidity modifying agent, etc.) as required. You. The fixing resin may be appropriately selected according to the fixing method (for example, see JP-A-57-97545). As an example, in the case of a hot roll fixing system, a styrene-acrylic copolymer, a styrene-butadiene copolymer, a polyester resin, an epoxy resin, and a mixed resin thereof are exemplified.
【００１７】上記磁性粉としては、フェライト、マグネ
タイトをはじめとする鉄、コバルト、ニッケルなどの強
磁性を示す元素を含む合金あるいは化合物が使用できる
が、磁性トナー中に含有せしめるために平均粒径が 0.1
〜３μｍ程度のものが望ましい。そして磁性トナーの保
磁力は実質的に磁性粉の保磁力により定まるので、磁性
粉の種類を変えることにより磁性トナーの保磁力を調整
できる。この場合、磁性粉の含有量が４０重量％未満で
あるとトナーの飛散が大となり、一方７５重量％を超え
ると定着性が低下するため、４０〜７５重量％の範囲が
よい。好ましい範囲は５０〜７０重量％である。As the magnetic powder, alloys or compounds containing ferromagnetic elements such as ferrite and magnetite, such as iron, cobalt and nickel, can be used. 0.1
A thickness of about 3 μm is desirable. Since the coercive force of the magnetic toner is substantially determined by the coercive force of the magnetic powder, the coercive force of the magnetic toner can be adjusted by changing the type of the magnetic powder. In this case, if the content of the magnetic powder is less than 40% by weight, the scattering of the toner becomes large, while if it exceeds 75% by weight, the fixing property is reduced. Therefore, the range of 40 to 75% by weight is preferable. The preferred range is 50-70% by weight.
【００１８】上記添加物としては、次のようなものが挙
げられる。荷電制御剤としては、負の荷電特性を有する
含金属（Ｃｒ）アゾ染料などが一般的である。また抵抗
調節剤としては、カーボンブラックが一般的である。ま
た流動性改質剤としては、前述の疎水性シリカに代表さ
れる酸化物微粒子がよく用いられている。これらの添加
量は、多すぎると磁性トナーの定着性を損なうので、一
般には１０重量％以下とされる。Examples of the above-mentioned additives include the following. As the charge control agent, a metal-containing (Cr) azo dye having negative charge characteristics is generally used. Carbon black is generally used as a resistance adjuster. As the fluidity modifier, oxide fine particles represented by the above-mentioned hydrophobic silica are often used. If the amount of these additives is too large, the fixability of the magnetic toner is impaired, so that the amount is generally 10% by weight or less.
【００１９】各種組成よりなる磁性トナーは、通常の一
成分系現像剤と同様に５〜３０μｍ（好ましくは６〜１
５μｍ）の平均粒径に調整される。本発明に用いる磁性
キャリアは、公知のものが使用できるが、画質の点から
は、マグネタイトやソフトフェライト（Ｎｉ−Ｚｎ系、
Ｍｇ−Ｚｎ系、Ｃｕ−Ｚｎ系、Ｂａ−Ｎｉ−Ｚｎ系等）
からなる酸化鉄を含むキャリアが好ましい。The magnetic toner having various compositions is 5 to 30 μm (preferably 6 to 1 μm) in the same manner as a usual one-component developer.
5 μm). As the magnetic carrier used in the present invention, known carriers can be used, but from the viewpoint of image quality, magnetite or soft ferrite (Ni-Zn based,
Mg-Zn system, Cu-Zn system, Ba-Ni-Zn system, etc.)
Carriers containing iron oxide consisting of are preferred.
【００２０】次に上記磁性キャリアの粒径は、通常の二
成分系現像剤と同様に平均粒径で５０〜１５０μｍの範
囲とするのがよい。本発明の現像剤は、磁性キャリアと
磁性トナーとを混合して調整されるが、磁性トナーの混
合比率（トナー濃度）を１０〜９５重量％とすることが
望ましい。トナー濃度が９５重量％を越えると、磁性ト
ナーが飛散し易くなり、又スペントトナー量が増え、一
方トナー濃度が１０重量％未満であると、画像のキレが
甘くなり、キャリア引きが発生する。トナー濃度は現像
条件等に応じて適宜定められるが、好ましい範囲は２０
〜８０重量％で、より好ましい範囲は３０〜７０重量％
である。The average particle diameter of the magnetic carrier is preferably in the range of 50 to 150 μm as in the case of a general two-component developer. The developer of the present invention is prepared by mixing a magnetic carrier and a magnetic toner. The mixing ratio (toner concentration) of the magnetic toner is desirably 10 to 95% by weight. When the toner concentration exceeds 95% by weight, the magnetic toner is liable to be scattered, and the amount of spent toner increases. On the other hand, when the toner concentration is less than 10% by weight, the sharpness of the image becomes weak and carrier pulling occurs. The toner concentration is appropriately determined according to the development conditions and the like.
To 80% by weight, more preferably 30 to 70% by weight.
It is.
【００２１】本発明の現像剤は、種々の現像方式に適用
できるが、永久磁石部材とスリーブとを共に回転させる
両方回転方式に有効である。特に後述する図１に示すよ
うに、永久磁石部材４とスリーブ５とを同方向（Ｘ方
向）に回転させると共に、現像剤３をこれらと同方向
（Ｙ方向）に、かつ現像領域において感光体１（Ｚ方
向）と逆方向に搬送する（但し、スリーブ５の回転数と
永久磁石部材４の回転数の比は 1/20 以下に設定するこ
とが好ましく、より好ましくは 1/10 〜 1/20 とする）
場合に本発明は有効である。また永久磁石部材４とスリ
ーブ５とを逆方向に回転させ、現像剤３をスリーブ５と
同方向に搬送する場合にも本発明はその効果を発揮でき
る。Although the developer of the present invention can be applied to various developing systems, it is effective for a both-rotating system in which the permanent magnet member and the sleeve are rotated together. In particular, as shown in FIG. 1 to be described later, the permanent magnet member 4 and the sleeve 5 are rotated in the same direction (X direction), and the developer 3 is moved in the same direction (Y direction) and the photosensitive member in the developing area. 1 (Z direction) (however, the ratio of the rotation speed of the sleeve 5 to the rotation speed of the permanent magnet member 4 is preferably set to 1/20 or less, more preferably 1/10 to 1 / 20)
In this case, the present invention is effective. The present invention can also exert the effect when the developer 3 is conveyed in the same direction as the sleeve 5 by rotating the permanent magnet member 4 and the sleeve 5 in opposite directions.
【００２２】[0022]
【作用】上記の構成により、磁性トナーの表面にも荷電
制御剤が存在することにより、帯電性が向上し、特に現
像装置の始動直後においても摩擦帯電が促進され、所謂
立上がり時間が短縮されるのである。According to the above construction, the charge control agent is also present on the surface of the magnetic toner, so that the chargeability is improved. In particular, even immediately after the start of the developing device, the triboelectric charge is promoted, and the so-called rise time is shortened. It is.
【００２３】[0023]
【実施例】 スチレン−ｎ−ブチルメタクリレート共重合体 ４２重量％ （Ｍｎ＝ 1.6×１０4 、Ｍｗ＝２１×１０4 ） 磁性粉 ５０重量％ （戸田工業製 ＥＰＴ５００） ポリオレフィン ５重量％ （三洋化成製 ビスコール５５０Ｐ） 荷電制御剤 ３重量％ （オリエント化学製 ボントロンＥ８１、体積固有抵抗１×１０15Ω・cm、at 4000 Ｖ／cm) 上記配合の原材料を乾式混合し、２００℃で加熱混練、
冷却固化後粉砕処理し、疎水性シリカ（日本アエロジル
製）を 0.5重量部添加して１２０℃で熱処理、分級等の
処理により平均粒径５〜２０μｍの磁性トナーとした。
次にこの磁性トナー１００重量部に前記のものと同一種
類の荷電制御剤（オリエント化学製 ボントロンＥ８
１）を0.05〜２重量部外添した。次にフェライトキャリ
ア（日立金属製 ＫＢＮ−２２０、粒径７４〜１４９μ
ｍ）４０重量部と上記磁性トナー６０重量部とを混合し
て磁性現像剤とした。Example Styrene-n-butyl methacrylate copolymer 42% by weight (Mn = 1.6 × 10 4 , Mw = 21 × 10 4 ) Magnetic powder 50% by weight (Toda Kogyo EPT500) Polyolefin 5% by weight (Sanyo Chemical Co., Ltd.) (Viscol 550P) Charge control agent 3% by weight (Bontron E81 manufactured by Orient Chemical Co., Ltd., volume resistivity: 1 × 10 15 Ω · cm, at 4000 V / cm) The raw materials having the above composition are dry-mixed and heated and kneaded at 200 ° C.
After cooling and solidifying, the mixture was pulverized, and 0.5 parts by weight of hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd.) was added, and a magnetic toner having an average particle size of 5 to 20 μm was obtained by heat treatment and classification at 120 ° C.
Next, 100 parts by weight of the magnetic toner is charged with a charge control agent of the same type as described above (Bontron E8 manufactured by Orient Chemical Co., Ltd.).
1) was externally added in an amount of 0.05 to 2 parts by weight. Next, use a ferrite carrier (KBN-220 manufactured by Hitachi Metals, particle size: 74 to 149 μm).
m) 40 parts by weight of the magnetic toner was mixed with 40 parts by weight to prepare a magnetic developer.
【００２４】図１は本発明の実施例における現像装置の
例を示す要部横断面図である。図１において１は感光体
であり、円筒状に形成して矢印Ｚ方向に回転自在に設け
る。２は現像剤槽であり、前記のようにして作製した現
像剤３を収容する。４は永久磁石部材であり、例えば円
柱状に形成し、外周に軸方向に延びる８個の磁極を設け
ると共に、前記感光体１と対向させ、かつ矢印Ｘ方向に
回転自在に設ける。５はスリーブであり、例えばステン
レス鋼のような非磁性材料により中空円筒状に形成し
て、前記永久磁石部材４と同軸的に設け、かつ矢印Ｘ方
向に回転自在とする。６はドクター部材であり、現像剤
槽２にその先端をスリーブ５の表面に臨ませて設ける。FIG. 1 is a cross-sectional view of an essential part showing an example of a developing device in an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a photoreceptor, which is formed in a cylindrical shape and is provided rotatably in an arrow Z direction. Reference numeral 2 denotes a developer tank, which stores the developer 3 prepared as described above. Reference numeral 4 denotes a permanent magnet member, which is formed, for example, in a columnar shape and has eight magnetic poles extending in the axial direction on the outer periphery, and is provided so as to face the photoconductor 1 and to be rotatable in the arrow X direction. Reference numeral 5 denotes a sleeve, which is formed of a non-magnetic material such as stainless steel into a hollow cylindrical shape, is provided coaxially with the permanent magnet member 4, and is rotatable in the direction of arrow X. Reference numeral 6 denotes a doctor member, which is provided in the developer tank 2 with its tip facing the surface of the sleeve 5.
【００２５】上記の構成により、感光体１、永久磁石部
材４およびスリーブ５を夫々反時計方向に回転させる
と、永久磁石部材４の磁力によって現像剤３がスリーブ
５の表面に吸着されてスリーブ５と同方向に搬送され、
感光体１の表面に担持された静電荷像を顕像化すること
ができるのである。このような現像装置において、前記
磁性現像剤を使用して現像を行い、画像評価した結果を
表１に示す。When the photosensitive member 1, the permanent magnet member 4, and the sleeve 5 are rotated in the counterclockwise direction, the developer 3 is attracted to the surface of the sleeve 5 by the magnetic force of the permanent magnet member 4. Transported in the same direction as
The electrostatic charge image carried on the surface of the photoconductor 1 can be visualized. In such a developing device, development was performed using the magnetic developer, and the results of image evaluation are shown in Table 1.
【００２６】上記現像条件について記述する。まず感光
体１としてＯＰＣを使用し、表面電位−６５０Ｖ、周速
６０mm／秒とし、バイアス電圧を−５５０Ｖとした。次
に永久磁石部材４とスリーブ５の回転数を夫々１２００
rpm および１６０rpm とした。この場合スリーブ５は外
径２０mmに形成し、永久磁石部材４は８極対称着磁と
し、スリーブ５上の表面磁束密度を６５０Ｇとした。な
お感光体１とスリーブ５との間の現像ギャップは0.35m
m、ドクター部材６とスリーブ５との間のドクターギャ
ップは0.30mmとした。The developing conditions will be described. First, OPC was used as the photoconductor 1, the surface potential was -650 V, the peripheral speed was 60 mm / sec, and the bias voltage was -550 V. Next, the rotational speeds of the permanent magnet member 4 and the sleeve 5 are each set to 1200.
rpm and 160 rpm. In this case, the sleeve 5 was formed to have an outer diameter of 20 mm, the permanent magnet member 4 was magnetized octapole symmetrically, and the surface magnetic flux density on the sleeve 5 was 650 G. The developing gap between the photosensitive member 1 and the sleeve 5 is 0.35 m
m, the doctor gap between the doctor member 6 and the sleeve 5 was 0.30 mm.
【００２７】[0027]
【表１】 [Table 1]
【００２８】表１から明らかなように、荷電制御剤の外
添を欠如するＮo.１においては、画像濃度および解像度
が何れも低いと共に、カブリが多い。荷電制御剤の外添
量の増加に伴って、画像濃度および解像度が向上すると
共にカブリが減少する（Ｎo.２〜Ｎo.５）。しかし荷電
制御剤の外添量が 2.0重量部であるＮo.６においては、
画像濃度は高くなるものの、解像度が低下し、かつカブ
リが大幅に増加することが認められる。As is evident from Table 1, in No. 1 lacking the external addition of the charge control agent, both image density and resolution are low and fog is high. As the external addition amount of the charge control agent increases, the image density and the resolution improve and the fog decreases (No. 2 to No. 5). However, in No. 6 where the external addition amount of the charge control agent is 2.0 parts by weight,
Although the image density is increased, it is recognized that the resolution is reduced and the fog is greatly increased.
【００２９】[0029]
【発明の効果】本発明は以上記述のような構成および作
用であるから、永久磁石部材とスリーブとが同一方向に
回転し、かつ現像領域において感光体表面と現像剤とが
逆方向に移動するような現像方式において、磁性現像剤
の摩擦帯電特性を大幅に向上させることができ、現像装
置始動後の立上がり所要時間を短縮することができる。
また連続現像時においても画像濃度が低下せず、安定し
た状態に保持することができるという効果がある。Since the present invention has the above-described structure and operation, the permanent magnet member and the sleeve rotate in the same direction, and the photosensitive member surface and the developer move in opposite directions in the developing area. In such a developing method, the frictional charging characteristics of the magnetic developer can be greatly improved, and the time required for starting up after the start of the developing device can be reduced.
In addition, there is an effect that the image density does not decrease even during continuous development, and the image can be maintained in a stable state.
【図１】本発明の実施例における現像装置の例を示す要
部横断面図である。FIG. 1 is a main part cross-sectional view illustrating an example of a developing device according to an embodiment of the present invention.
１ 感光体 ３ 現像剤 ４ 永久磁石部材 ５ スリーブ DESCRIPTION OF SYMBOLS 1 Photoreceptor 3 Developer 4 Permanent magnet member 5 Sleeve
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.6，ＤＢ名) G03G 9/097 G03G 9/08 G03G 9/083──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. 6 , DB name) G03G 9/097 G03G 9/08 G03G 9/083
Claims (1)
部材とを共に回転させてスリーブ上に保持した現像剤を
スリーブと同方向に搬送する磁気ブラシ現像法に使用す
る、少なくとも結着樹脂、磁性粉および負帯電性染料か
らなる荷電制御剤を含有する磁性トナーと磁性キャリア
とを混合してなる磁性現像剤において、磁性粉の含有量
を４０〜７５重量％とし、荷電制御剤の含有量を 0.5〜
５重量％とすると共に、磁性トナー１００重量部に対し
て前記荷電制御剤と同極性でかつ体積固有抵抗の差が１
０ 2 Ω・cm以下である荷電制御剤を0.05〜１重量部外添
したことを特徴とする磁性現像剤。1. A sleeve and a permanent magnet made of a non-magnetic material.
The developer held on the sleeve by rotating the members together
Used for the magnetic brush developing method to transport in the same direction as the sleeve.
At least binder resin, magnetic powder and negatively chargeable dye
In a magnetic developer obtained by mixing a magnetic toner containing a charge control agent and a magnetic carrier, the content of the magnetic powder is set to 40 to 75% by weight, and the content of the charge control agent is set to 0.5 to 75% by weight.
5% by weight , and a difference in volume resistivity between the charge control agent and the charge control agent is 1 with respect to 100 parts by weight of the magnetic toner.
A magnetic developer to which 0.05 to 1 part by weight of a charge control agent having a density of not more than 0 2 Ω · cm is externally added.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3257386A JP2763426B2 (en) | 1991-10-04 | 1991-10-04 | Magnetic developer |
| US07/950,900 US5429900A (en) | 1991-10-04 | 1992-09-25 | Magnetic developer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3257386A JP2763426B2 (en) | 1991-10-04 | 1991-10-04 | Magnetic developer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05100488A JPH05100488A (en) | 1993-04-23 |
| JP2763426B2 true JP2763426B2 (en) | 1998-06-11 |
Family
ID=17305671
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3257386A Expired - Fee Related JP2763426B2 (en) | 1991-10-04 | 1991-10-04 | Magnetic developer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2763426B2 (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5825641A (en) * | 1981-08-08 | 1983-02-15 | Canon Inc | Developer |
-
1991
- 1991-10-04 JP JP3257386A patent/JP2763426B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05100488A (en) | 1993-04-23 |
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