JPH04321074A - Thin dielectric roll and production thereof - Google Patents
Thin dielectric roll and production thereofInfo
- Publication number
- JPH04321074A JPH04321074A JP3116881A JP11688191A JPH04321074A JP H04321074 A JPH04321074 A JP H04321074A JP 3116881 A JP3116881 A JP 3116881A JP 11688191 A JP11688191 A JP 11688191A JP H04321074 A JPH04321074 A JP H04321074A
- Authority
- JP
- Japan
- Prior art keywords
- ferrite
- thin dielectric
- dielectric roll
- thin
- roll
- 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 6
- 229910000859 α-Fe Inorganic materials 0.000 claims abstract description 53
- 239000000843 powder Substances 0.000 claims abstract description 31
- 238000000034 method Methods 0.000 claims abstract description 15
- 238000010298 pulverizing process Methods 0.000 claims abstract description 12
- 239000002491 polymer binding agent Substances 0.000 claims abstract 4
- 239000002245 particle Substances 0.000 claims description 15
- 229920000620 organic polymer Polymers 0.000 claims description 4
- 229920005992 thermoplastic resin Polymers 0.000 claims description 4
- 238000001125 extrusion Methods 0.000 claims description 2
- 238000001746 injection moulding Methods 0.000 claims description 2
- 239000000758 substrate Substances 0.000 claims 2
- 238000010030 laminating Methods 0.000 abstract 1
- 229920005596 polymer binder Polymers 0.000 abstract 1
- 229920001971 elastomer Polymers 0.000 description 13
- 239000005060 rubber Substances 0.000 description 13
- AJCDFVKYMIUXCR-UHFFFAOYSA-N oxobarium;oxo(oxoferriooxy)iron Chemical compound [Ba]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O AJCDFVKYMIUXCR-UHFFFAOYSA-N 0.000 description 9
- 230000003746 surface roughness Effects 0.000 description 6
- 239000000654 additive Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000011230 binding agent Substances 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 239000004709 Chlorinated polyethylene Substances 0.000 description 3
- 239000011362 coarse particle Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 238000004132 cross linking Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 239000000945 filler Substances 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 108091008695 photoreceptors Proteins 0.000 description 2
- -1 polyethylene, ethylene Polymers 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229910052712 strontium Inorganic materials 0.000 description 2
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 2
- 238000004073 vulcanization Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 239000007822 coupling agent Substances 0.000 description 1
- 239000003431 cross linking reagent Substances 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 238000009837 dry grinding Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- HQQADJVZYDDRJT-UHFFFAOYSA-N ethene;prop-1-ene Chemical group C=C.CC=C HQQADJVZYDDRJT-UHFFFAOYSA-N 0.000 description 1
- 239000007952 growth promoter Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- OCWMFVJKFWXKNZ-UHFFFAOYSA-L lead(2+);oxygen(2-);sulfate Chemical compound [O-2].[O-2].[O-2].[Pb+2].[Pb+2].[Pb+2].[Pb+2].[O-]S([O-])(=O)=O OCWMFVJKFWXKNZ-UHFFFAOYSA-L 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000013081 microcrystal Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 239000000088 plastic resin Substances 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000010057 rubber processing Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000012756 surface treatment agent Substances 0.000 description 1
- 229920001897 terpolymer Polymers 0.000 description 1
- 238000003856 thermoforming Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 229920001567 vinyl ester resin Polymers 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
Landscapes
- Magnetic Brush Developing In Electrophotography (AREA)
- Dry Development In Electrophotography (AREA)
Abstract
Description
【0001】0001
【産業上の利用分野】本発明は複写機、ファクシミリや
レーザプリンタ等の電子写真方式現像装置に用いる現像
ロールに関し、更に詳しくはこの現像ロールの表面に直
接現像剤が接触するスリーブを用いない直接接触式電子
写真現像法に適した磁性を有する誘電体現像ロールに関
する。[Field of Industrial Application] The present invention relates to a developing roll used in electrophotographic developing devices such as copying machines, facsimile machines, and laser printers, and more specifically, the present invention relates to a developing roll used in electrophotographic developing devices such as copying machines, facsimile machines, and laser printers. The present invention relates to a dielectric developing roll having magnetism suitable for contact electrophotographic development.
【0002】0002
【従来の技術】複写機やファクシミリ等の電子写真現像
装置の一つの方式に、円柱または円筒状の金属製シャフ
トの外周にゴムマグネットが配置され、且つその表面を
細かい表面肌に仕上げた誘電体現像ロール(以下、誘電
体ロールと称す)を使用し、該誘電体ロールの表面にト
ナーを直接磁着させる直接接触方式の現像方式が提案さ
れている。例えば、特開昭63−223675号公報記
載の現像装置では、感光体からなる潜像担持体に近接配
置される1成分磁性トナーを担持しながら現像領域に搬
送する現像剤搬送部材として、外周に磁力を有する磁石
体を用い、該磁石体の表面に集められたトナーを、帯電
部材との間隙で摩擦帯電させることによって磁石体表面
にトナー薄層を形成し、該トナー薄層を磁石体の回転と
ともに移動させることによってトナーを感光体に搬送す
るものを用いている。このようなマグネットロールにお
けるシャフト軸周に形成される磁石層は、ゴム系バイン
ダーに等方性バリウムフェライトを分散したゴムマグネ
ットから形成されており、その層厚は1mm前後に設定
されている。そして該ロールにて搬送されるトナーの量
を規制する目的でゴム質誘電体ロール表面に硬質のブレ
ードが圧設されている。[Prior Art] One method of electrophotographic developing devices such as copying machines and facsimiles uses a dielectric material in which a rubber magnet is arranged around the outer periphery of a cylindrical or cylindrical metal shaft, and the surface of the magnet is finished with a fine surface texture. A direct contact developing method has been proposed in which a developing roll (hereinafter referred to as a dielectric roll) is used and toner is directly magnetically attached to the surface of the dielectric roll. For example, in the developing device described in Japanese Patent Application Laid-Open No. 63-223675, a developer conveying member disposed close to a latent image carrier made of a photoreceptor and carrying one-component magnetic toner while conveying it to a developing area is installed on the outer periphery. A thin layer of toner is formed on the surface of the magnet by using a magnet with magnetic force and frictionally charging the toner collected on the surface of the magnet in the gap between the charging member and the thin layer of toner. A toner is used that conveys toner to a photoreceptor by rotating and moving the toner. The magnet layer formed around the shaft axis of such a magnet roll is formed from a rubber magnet in which isotropic barium ferrite is dispersed in a rubber binder, and the layer thickness is set to about 1 mm. A hard blade is pressed onto the surface of the rubber dielectric roll for the purpose of regulating the amount of toner conveyed by the roll.
【0003】かかる磁性を有する誘電体ロールはゴム原
料をフェライト等の配合物と共に混練してシート状とし
たものを金属シャフト上に巻き付けた後、高温でプレス
加工成形し、次いで表面を研磨仕上げする方法で製造さ
れている。[0003] Such a magnetic dielectric roll is made by kneading a rubber raw material with a compound such as ferrite to form a sheet, which is wound around a metal shaft, then press-formed at high temperature, and then the surface is polished. manufactured by the method.
【0004】0004
【発明で解決しようとする課題】このようなゴム系誘電
体ロールでは以下の様な問題があり、その解決が求めら
れていた。■ゴムマグネット改質の為の架橋や、ゴムマ
グネットをシャフトに接着する為に行う高温プレス時に
、マグネット層に割れが生じたり、シャフトとマグネッ
ト間に密着不良による間隙が発生したりすることがあり
、又、プレス圧力が部分的に不足した場合、加硫・架橋
時に発生するガスにより気泡が形成されて不均一な部分
が生じ、これら理由により磁界強度等の誘電体ロールの
特性に部分的変化が生じて、紙に転写された現像画像に
濃淡ムラが発生する問題がある。又、直接接触式電子写
真現像法においては誘電体ロール自体を帯電させる為、
その帯電特性が重要であるが、ゴムの加硫・架橋用の薬
剤の残留物やその他の不純物の存在に起因する帯電特性
の変動が問題となる。■ゴムは加工時の粘度が高いので
フェライト粉のような充填剤を混合すると更に粘度が上
昇して、加工が困難となる。特に平均粒子径が小さいフ
ェライト粉を用いるとこの傾向が顕著であることから、
加工性をより良くする為に、大きな粒径のフェライト粉
を使用しているが、粒径の大きいフェライト粉を使用す
るとマグネットロールの表面粗度を悪化させる問題があ
り、他方、表面粗度を改良する為に小粒径のフェライト
粉(異方性フェライト粉はこの条件を満たす)を用いる
と成形特性が悪化し、加工時トルクが大になる等、加工
上の制限があった。■ゴム加工ではゴム原料がクラム(
塊)状であるのでフェライト粉の均一分散が困難で、こ
の為、多大の工数が必要となるうえに、成形マグネット
の各部でフェライト含有量の不均一が生じやすく、着磁
の均一性が損なわれやすい。■一定の表面粗度を得る為
に研磨等を行っているものの、比較的大きい平均粒子系
のフェライト粉を用いているので粗大粒子の混入が多く
所望の微細な表面肌を得にくくて品質が安定せず、現像
画像の不均一が生じていた。■使用環境の湿度条件の変
化や長時間経過にともなってマグネット層の電気特性の
変化があり、画像濃度が湿度や時間経過によって影響を
受け、安定しない。[Problems to be Solved by the Invention] Such rubber-based dielectric rolls have the following problems, and solutions to these problems have been sought. ■During cross-linking to modify rubber magnets or high-temperature pressing to bond rubber magnets to shafts, cracks may occur in the magnet layer or gaps may occur due to poor adhesion between the shaft and magnet. Also, if the press pressure is partially insufficient, bubbles are formed due to the gas generated during vulcanization and crosslinking, resulting in uneven areas, and due to these reasons, the properties of the dielectric roll such as magnetic field strength may partially change. This causes a problem in that unevenness in density occurs in the developed image transferred to the paper. In addition, in the direct contact electrophotographic development method, since the dielectric roll itself is charged,
The charging characteristics are important, but fluctuations in the charging characteristics due to the presence of residues of chemicals for vulcanization and crosslinking of rubber and other impurities pose a problem. ■Rubber has a high viscosity during processing, so when fillers such as ferrite powder are mixed in, the viscosity increases even more, making processing difficult. This tendency is particularly noticeable when using ferrite powder with a small average particle size.
Ferrite powder with a large particle size is used to improve processability, but there is a problem that using ferrite powder with a large particle size deteriorates the surface roughness of the magnet roll. If ferrite powder with a small particle size (anisotropic ferrite powder satisfies this condition) is used to improve the process, the molding properties deteriorate and there are limitations in processing, such as increased torque during processing. ■In rubber processing, the rubber raw material is crumb (
Since the ferrite powder is in the form of lumps, it is difficult to uniformly disperse the ferrite powder, which requires a large amount of man-hours, and the ferrite content tends to be uneven in each part of the molded magnet, impairing the uniformity of magnetization. It's easy to get lost. ■Although polishing etc. are performed to obtain a certain surface roughness, since ferrite powder with relatively large average particles is used, there are many coarse particles mixed in, making it difficult to obtain the desired fine surface texture, resulting in poor quality. It was not stable and the developed image was non-uniform. ■The electrical characteristics of the magnetic layer change as the humidity conditions of the usage environment change and over time, and the image density is affected by humidity and the passage of time, making it unstable.
【0005】そこで、本発明者らはゴムの代わりに熱可
塑性樹脂を用いればこれらの困難のほとんどを一挙に解
決可能であることを見いだし、■無機質の磁石粉を大量
に充填してなお機械的強度を確保することができ、■マ
グネットと接触する対象物にマグネット成分の移行や粘
着の問題が発生せず、■熱成形時の溶融粘度が低く、成
形性が良好なマグネット組成物として、ビニルエステル
含有量が20〜40重量%であって且つメルトインデッ
クスが50以上のオレフィン/ビニルエステル共重合体
と塩素化ポリエチレンの混合物をバインダーとするフェ
ライト系フレキシブルマグネット組成物を既に提案して
いる。The inventors of the present invention found that most of these difficulties could be solved at once by using thermoplastic resin instead of rubber. As a magnet composition that can secure strength, ■ prevent the transfer of magnetic components or adhesion problems to objects that come into contact with the magnet, and ■ have low melt viscosity during thermoforming and good moldability, vinyl A ferritic flexible magnet composition has already been proposed in which the binder is a mixture of an olefin/vinyl ester copolymer and chlorinated polyethylene having an ester content of 20 to 40% by weight and a melt index of 50 or more.
【0006】しかしながら、この様に熱可塑性樹脂を用
いても、湿度変化や長時間経過に伴うマグネット層の電
気特性の変化は顕著には改良されなかった。本発明はか
かる電気特性の安定性を改良することを目的とする。However, even when a thermoplastic resin is used in this manner, changes in the electrical characteristics of the magnet layer due to changes in humidity or over a long period of time have not been significantly improved. The present invention aims to improve the stability of such electrical properties.
【0007】[0007]
【課題を解決するための手段】従来技術のかかる課題を
解決する為に、誘電体ロールの電気特性に影響を与える
因子について鋭意研究した結果、電気特性が安定しない
のは従来使用されていたフェライトに原因があることを
見出し、本発明に到達した。即ち、フェライト中には、
当該フェライトを焼成する際に使用した酸化鉄原料中に
存在したイオン性成分や各種添加物が、残留物として残
っており、この残留物が湿度の増加に伴って電気伝導性
を高め、電気特性変動の主因となっていることが分かっ
た。そしてこの残留物は、乾式粉砕法を用いたときに大
きいことが分かった。これらのことから、従来のフェラ
イト粉の電気特性が安定しなかったのは、フェライト粉
を得る手段として乾式粉砕法を用いていた為に、電気伝
導性成分が焼成時のまま残留していることに最大要因が
あることを見出した。[Means for Solving the Problems] In order to solve the problems of the conventional technology, we conducted extensive research into the factors that affect the electrical properties of dielectric rolls.We found that the electrical properties of dielectric rolls are unstable due to the ferrite used in the past. The present invention was achieved by discovering that there is a cause for this. That is, in ferrite,
Ionic components and various additives present in the iron oxide raw material used when firing the ferrite remain as residues, and as humidity increases, this residue increases electrical conductivity and deteriorates electrical properties. It was found that this was the main cause of variation. And this residue was found to be large when dry grinding method was used. Based on these facts, the reason why the electrical properties of conventional ferrite powder were not stable was because dry pulverization was used as a means of obtaining ferrite powder, and electrically conductive components remained as they were during firing. It was found that the largest factor was
【0008】また、電気特性との直接的な関係はないが
、乾式粉砕では粉砕程度に限界があり、粉砕によって得
られる粒子は比較的大きな平均粒子径のものにとどまる
結果、粗大粒子の混入が多く現像ローラーの表面粗度に
対する悪影響も内包していることもわかった。[0008]Although there is no direct relationship with electrical properties, there is a limit to the degree of pulverization in dry pulverization, and the particles obtained by pulverization have a relatively large average particle size, resulting in the possibility of contamination with coarse particles. It was also found that many of them also have an adverse effect on the surface roughness of the developing roller.
【0009】本発明は、電気伝導性成分の残留量が少な
いフェライト粉を用いてボンド磁石層を形成することに
より、大気中の湿度増加や長時間使用に伴って吸湿量が
増加したときにも、電気特性の変動が少なく、安定した
電気特性を有する薄肉誘電体ロールを提供せんとするも
のであり、あわせて薄肉誘電体ロールの表面粗度の改善
もはかったものである。[0009] The present invention uses ferrite powder with a small amount of residual electrically conductive components to form a bonded magnet layer, so that it can be used even when the amount of moisture absorbed increases due to increased atmospheric humidity or long-term use. It is an object of the present invention to provide a thin dielectric roll having stable electrical characteristics with little variation in electrical characteristics, and also to improve the surface roughness of the thin dielectric roll.
【0010】そこで、どの様なフェライトが好適かを研
究した結果、湿式微粉砕によって作製されたフェライト
粉を使用すれば、本発明の目的を達することができるこ
とを見出した。フェライト粉の平均粒子径は1.5μm
以下とすることが好ましく、また、湿式微粉砕するフェ
ライトは結晶サイズが1μm未満の微結晶の集合体であ
る等方性フェライトであることが好ましい。[0010] As a result of researching what kind of ferrite is suitable, it was found that the object of the present invention can be achieved by using ferrite powder produced by wet pulverization. The average particle size of ferrite powder is 1.5μm
The ferrite to be wet-pulverized is preferably isotropic ferrite, which is an aggregate of microcrystals with a crystal size of less than 1 μm.
【0011】湿式微粉砕を行ったフェライトが好適な理
由は、乾式法よりも一層細かく粉砕出来て粗大粒子が大
幅に少ないこと、並びに湿式法であるので前記したイオ
ン性電気伝導性残留物が粉砕媒体である水にて洗浄除去
されることの2点にあるものと推定される。[0011] The reason why ferrite subjected to wet pulverization is preferable is that it can be pulverized more finely than the dry method, and there are significantly fewer coarse particles, and because it is a wet method, the above-mentioned ionic electrically conductive residue is not pulverized. It is presumed that this is due to two reasons: it is washed away with water, which is a medium.
【0012】ところで、異方性フェライト粉と称するも
のは、通常、湿式微粉砕していることから、平均粒子径
の大きさの観点からは本発明の目的にかなうが、異方性
フェライト粉はその製造過程で異方性とするために各種
の結晶成長促進剤その他の添加剤を加えて焼成している
ため、フェライト粉中の電気伝導性成分の残留量が多く
、あまり好ましくない。これに比べて、微結晶性等方性
フェライトの場合にはこの様な添加剤を加えること無く
製造されるので、電気伝導性物質の残留が基本的に少な
く一層好適なのである。更に、異方性フェライト粉を用
いた場合、薄肉での成形を行うと成形時のせん断応力に
よりフェライト粒子の部分的な配向が発生し、磁気特性
に僅かながら変動が生ずるが、微結晶等方性フェライト
粉ではこのような問題の発生が全くないという利点もあ
る。By the way, the so-called anisotropic ferrite powder is usually wet-pulverized, so it meets the purpose of the present invention from the viewpoint of the average particle size, but the anisotropic ferrite powder During the manufacturing process, various crystal growth promoters and other additives are added and fired in order to make the powder anisotropic, so there is a large amount of electrically conductive components remaining in the ferrite powder, which is not very desirable. In comparison, microcrystalline isotropic ferrite is produced without adding such additives, and therefore is more suitable since it basically leaves less electrically conductive material. Furthermore, when anisotropic ferrite powder is used and molded into a thin wall, partial orientation of the ferrite particles occurs due to shear stress during molding, causing slight fluctuations in magnetic properties, but microcrystalline isotropic Ferrite powder has the advantage that such problems do not occur at all.
【0013】以上の理由により、本発明では湿式粉砕法
で製造されたフェライト粉を用い、特に微結晶性等方性
フェライトを湿式粉砕法により1.5μm以下の平均粒
径に粉砕したものを用いる。For the above reasons, the present invention uses ferrite powder produced by a wet pulverization method, particularly microcrystalline isotropic ferrite pulverized to an average particle size of 1.5 μm or less by a wet pulverization method. .
【0014】次に本発明の詳細を実施例に基づき説明す
る。本発明は湿式微粉砕法で製造されたフェライト粉を
用いることが特徴である。使用するフェライトはマグネ
トプラムバイト型フェライトであるが、バリウムフェラ
イト及びストロンチウムフェライトが好適であり、バリ
ウムフェライト及びストロンチウムフェライトのいずれ
を使用するかは、作製する誘電体ロールが必要とする電
気抵抗率の水準によって適宜選択すれば良い。しかし、
等方性フェライトとして工業的に入手し易いのはバリウ
ムフェライトであることから、バリウムフェライトの使
用が工業的には有利である。Next, details of the present invention will be explained based on examples. The present invention is characterized in that it uses ferrite powder produced by a wet pulverization method. The ferrite used is a magnetoplumbite type ferrite, but barium ferrite and strontium ferrite are preferred, and whether barium ferrite or strontium ferrite is used depends on the level of electrical resistivity required by the dielectric roll to be manufactured. It may be selected accordingly. but,
Since barium ferrite is industrially easily available as isotropic ferrite, it is industrially advantageous to use barium ferrite.
【0015】本発明においてはフェライト粉のバインダ
ーは有機高分子化合物から適宜選択する。ゴム材料も使
用可能であるが、前記した種々の問題があることから、
熱可塑性樹脂が好適である。フレキシブルな材料が必要
な場合には塩素化ポリエチレン、エチレン/酢酸ビニル
コポリマー、無架硫のエチレンプロピレンジェンターポ
リマー等が例示でき、これらのバインダーを用いた場合
には押出成形法が加工方法として好適である。硬質の材
料が必要な場合にはポリアミド、ポリプロピレン、線状
飽和ポリエステル等が例示でき、この場合は射出成形法
が好適である。また、加工性、熱安定性、機械的強度そ
の他を改善する目的で各種の添加物を添加することも、
本発明のローラー特性を損なわない範囲であれば採用で
きる。添加剤としては、例えばカップリング剤等の表面
処理剤、可塑剤、安定剤、滑材、架硫剤または架橋剤、
充填剤などがある。In the present invention, the binder for the ferrite powder is appropriately selected from organic polymer compounds. Rubber materials can also be used, but because of the various problems mentioned above,
Thermoplastic resins are preferred. When a flexible material is required, examples include chlorinated polyethylene, ethylene/vinyl acetate copolymer, uncrosslinked ethylene propylene terpolymer, etc. When using these binders, extrusion molding is a suitable processing method. be. When a hard material is required, examples include polyamide, polypropylene, linear saturated polyester, etc. In this case, injection molding is preferred. Additionally, various additives may be added to improve processability, thermal stability, mechanical strength, etc.
It can be adopted as long as it does not impair the roller properties of the present invention. Examples of additives include surface treatment agents such as coupling agents, plasticizers, stabilizers, lubricants, cross-sulfurizing agents or cross-linking agents,
There are fillers, etc.
【0016】次に本発明の効果を確かめるために行った
具体的実施例について述べる。
実施例1
塩素含有率30重量%の塩素化ポリエチレン100重量
部と三塩基性硫酸鉛3重量部からなる樹脂混合物を40
体積%と、最大結晶粒界径が概ね0.5μmのバリウム
フェライトを水中で湿式微粉砕し、平均粒子径1.2μ
mに調整をした等方性バリウムフェライト粉60体積%
とを高速回転刃ミキサーで混合した後、熱ロールミルで
120℃にて混練、カットして成形用可塑性樹脂マグネ
ット混練物を得た。これを直径18mm、長さ240m
mのステンレス製シャフト上にクロスヘッドダイを装着
した押出機でシャフト表面に1.2mmの厚さになるよ
うに140℃で被覆成形した。成形物を旋盤にて直径が
20mmになるよう精密切削し、磁性誘電体層である樹
脂マグネット層の厚みを1mmとし、この誘電体ロール
を20℃、湿度50%(50%RH)の環境下で24時
間状態調節して、同条件下で体積固有抵抗を測定した。
次に、このロールを40℃、90%RHで24時間加湿
処理し、先と同じ条件で状態調節した後の体積固有抵抗
を測定した。結果を表1に示す。Next, specific examples carried out to confirm the effects of the present invention will be described. Example 1 40 parts of a resin mixture consisting of 100 parts by weight of chlorinated polyethylene with a chlorine content of 30% by weight and 3 parts by weight of tribasic lead sulfate
Barium ferrite with volume% and maximum grain boundary diameter of approximately 0.5 μm was wet-pulverized in water to obtain an average particle size of 1.2 μm.
60% by volume of isotropic barium ferrite powder adjusted to m
After mixing with a high-speed rotary blade mixer, the mixture was kneaded at 120° C. with a hot roll mill and cut to obtain a plastic resin magnet kneaded product for molding. This has a diameter of 18 mm and a length of 240 m.
Using an extruder equipped with a crosshead die on a stainless steel shaft, the shaft surface was coated at 140° C. to a thickness of 1.2 mm. The molded product was precisely cut using a lathe to a diameter of 20 mm, the resin magnet layer, which is a magnetic dielectric layer, had a thickness of 1 mm, and this dielectric roll was cut in an environment of 20°C and 50% humidity (50% RH). Conditions were adjusted for 24 hours, and the volume resistivity was measured under the same conditions. Next, this roll was subjected to humidification treatment at 40° C. and 90% RH for 24 hours, and the volume resistivity was measured after conditioning under the same conditions as before. The results are shown in Table 1.
【0017】実施例2
平均粒子径1.0μmの湿式粉砕異方性バリウムフェラ
イト粉を用いる以外は実施例1と全く同じにしてロール
状物を作製し実施例1と同様、評価した。結果を表1に
示した。Example 2 A roll-shaped product was prepared in exactly the same manner as in Example 1, except that wet-pulverized anisotropic barium ferrite powder having an average particle diameter of 1.0 μm was used, and evaluated in the same manner as in Example 1. The results are shown in Table 1.
【0018】比較例
フェライト粉として乾式粉砕をした1.7μmの平均粒
子径を有する等方性バリウムフェライト粉を用いること
以外は実施例1と全く同様にしてロール状物を作製し実
施例1と同様、評価した。結果を表1に示した。Comparative Example A roll-shaped product was prepared in the same manner as in Example 1 except that dry-pulverized isotropic barium ferrite powder having an average particle diameter of 1.7 μm was used as the ferrite powder. Similarly evaluated. The results are shown in Table 1.
【0019】[0019]
【表1】[Table 1]
【0020】表1から明かな様に、乾式微粉砕フェライ
トを用いた比較例では加湿前と加湿後の体積抵抗率は7
0%もの大幅な抵抗値変化があったのに対し、湿式微粉
砕フェライトを用いた実施例1,2は高々20%前後程
度しか変化せず、本発明が湿度環境の変化に対して、安
定した電気特性を有していることが分かる。また実施例
1と実施例2との比較では、より細かいフェライト粉を
用いた実施例2の方が抵抗変化はより少なかった。また
、得られたロールを外観観察した結果、比較例のロール
表面には多数のピンホール様の欠陥が見出されたのに対
し、実施例1,2では切削したマグネット層表面に欠陥
はなく、表面粗度が細かく且つ均一な表面肌を有するロ
ールが得られた。As is clear from Table 1, in the comparative example using dry finely pulverized ferrite, the volume resistivity before and after humidification was 7.
While there was a significant change in resistance value of 0%, in Examples 1 and 2 using wet-pulverized ferrite, the change was only around 20% at most, indicating that the present invention is stable against changes in the humidity environment. It can be seen that it has very good electrical characteristics. Further, in a comparison between Example 1 and Example 2, the resistance change was smaller in Example 2, which used finer ferrite powder. Furthermore, as a result of observing the appearance of the obtained roll, a large number of pinhole-like defects were found on the roll surface of the comparative example, whereas in Examples 1 and 2, there were no defects on the cut magnetic layer surface. A roll having a fine surface roughness and a uniform surface texture was obtained.
【0021】[0021]
【発明の効果】本発明によれば、磁性を有する薄肉誘電
体ロールにおける課題であった、湿度環境変化や経時変
化に起因する電気特性の変化を著しく抑制することが可
能となるとともに、表面欠陥もなく表面粗度の細かい直
接接触式電子写真現像法に適した薄肉誘電体ロールを得
ることができ、且つこのような電気特性、表面状態が安
定した薄肉誘電体ロールを安定的に量産することが可能
となる。Effects of the Invention According to the present invention, it is possible to significantly suppress changes in electrical properties caused by changes in the humidity environment and changes over time, which have been a problem with magnetic thin dielectric rolls, and also to reduce surface defects. To obtain a thin dielectric roll suitable for direct contact electrophotographic development with a fine surface roughness and to stably mass-produce such a thin dielectric roll with stable electrical properties and surface condition. becomes possible.
Claims (6)
有機高分子バインダーとからなる薄肉ボンド磁石層を導
電性基体上に積層してなる薄肉誘電体ロールにおいて、
前記フェライトが湿式微粉砕法にて作製されたフェライ
ト粉であることを特徴とする薄肉誘電体ロール。1. A thin dielectric roll comprising a thin bonded magnet layer made of magnetoplumbite ferrite and an organic polymer binder laminated on a conductive substrate, comprising:
A thin dielectric roll characterized in that the ferrite is ferrite powder produced by a wet pulverization method.
平均粒子径1.5μm以下の湿式粉砕等方性フェライト
粉であることを特徴とする請求項1記載の薄肉誘電体ロ
ール。2. The thin dielectric roll according to claim 1, wherein the magnetoplumbite type ferrite is wet-pulverized isotropic ferrite powder having an average particle size of 1.5 μm or less.
であることを特徴とする請求項1又は2記載の薄肉誘電
体ロール。3. The thin dielectric roll according to claim 1 or 2, wherein the organic polymer binder is a thermoplastic resin.
有機高分子バインダーとからなる薄肉ボンド磁石層を導
電性基体上に積層してなる薄肉誘電体ロールにおいて、
前記フェライトを湿式微粉砕法にて作製してなる薄肉誘
電体ロールの製法。4. A thin dielectric roll comprising a thin bonded magnet layer made of magnetoplumbite ferrite and an organic polymer binder laminated on a conductive substrate,
A method for manufacturing a thin dielectric roll by manufacturing the ferrite by a wet pulverization method.
成形してなる請求項4記載の薄肉誘電体ロールの製法。5. The method for producing a thin dielectric roll according to claim 4, wherein the bonded magnet layer is coated by injection molding.
成形してなる請求項4記載の薄肉誘電体ロールの製法。6. The method for producing a thin dielectric roll according to claim 4, wherein the bonded magnet layer is coated by extrusion molding.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3116881A JPH04321074A (en) | 1991-04-19 | 1991-04-19 | Thin dielectric roll and production thereof |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3116881A JPH04321074A (en) | 1991-04-19 | 1991-04-19 | Thin dielectric roll and production thereof |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH04321074A true JPH04321074A (en) | 1992-11-11 |
Family
ID=14697953
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3116881A Pending JPH04321074A (en) | 1991-04-19 | 1991-04-19 | Thin dielectric roll and production thereof |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH04321074A (en) |
-
1991
- 1991-04-19 JP JP3116881A patent/JPH04321074A/en active Pending
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