JPS62238715A - Method for injection molding of plastic magnet roll - Google Patents
Method for injection molding of plastic magnet rollInfo
- Publication number
- JPS62238715A JPS62238715A JP8307986A JP8307986A JPS62238715A JP S62238715 A JPS62238715 A JP S62238715A JP 8307986 A JP8307986 A JP 8307986A JP 8307986 A JP8307986 A JP 8307986A JP S62238715 A JPS62238715 A JP S62238715A
- Authority
- JP
- Japan
- Prior art keywords
- mixture
- magnet roll
- plastic magnet
- injection molding
- hopper
- 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
- 239000004033 plastic Substances 0.000 title claims abstract description 18
- 229920003023 plastic Polymers 0.000 title claims abstract description 18
- 238000001746 injection moulding Methods 0.000 title claims abstract description 14
- 238000000034 method Methods 0.000 title claims abstract description 9
- 239000000203 mixture Substances 0.000 claims abstract description 17
- 238000002844 melting Methods 0.000 claims abstract description 7
- 230000008018 melting Effects 0.000 claims abstract description 7
- 239000006247 magnetic powder Substances 0.000 claims abstract description 6
- 229920005992 thermoplastic resin Polymers 0.000 claims abstract description 5
- 238000002347 injection Methods 0.000 abstract description 17
- 239000007924 injection Substances 0.000 abstract description 17
- 238000000465 moulding Methods 0.000 abstract description 8
- 239000002994 raw material Substances 0.000 abstract description 8
- 230000004907 flux Effects 0.000 abstract description 7
- 238000010438 heat treatment Methods 0.000 abstract description 4
- 238000010276 construction Methods 0.000 abstract 1
- 230000009021 linear effect Effects 0.000 abstract 1
- 239000002075 main ingredient Substances 0.000 abstract 1
- 150000001875 compounds Chemical class 0.000 description 6
- 230000000694 effects Effects 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910001047 Hard ferrite Inorganic materials 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000007596 consolidation process Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229920006244 ethylene-ethyl acrylate Polymers 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000012768 molten material Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- -1 polyethylene, ethylene Polymers 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
Landscapes
- Injection Moulding Of Plastics Or The Like (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は熱可塑性樹脂と磁性粉とを主体とする混合物を
加熱溶融して成形型内へ充填して成形するプラスチック
系のマグネットロールの射出成形方法の改良に関するも
のである。[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to injection molding of plastic magnetic rolls, which are formed by heating and melting a mixture mainly consisting of thermoplastic resin and magnetic powder and filling it into a mold. This invention relates to improvements in molding methods.
従来電子写真装置において磁気ブラシの形成手段として
使用するマグネットロールには９円柱状に成形して得ら
れたフェライト磁石の外表面に磁極を設けたものが一般
に使用されていたが、近年電子写真装置の軽量化、小型
化等の要請により。Conventionally, the magnet roll used as a means for forming magnetic brushes in electrophotographic equipment has generally been a ferrite magnet formed into a 9-cylindrical shape with magnetic poles provided on the outer surface, but in recent years electrophotographic equipment Due to requests for lighter weight and smaller size.
プラスチックマグネットロールが増加してきた。Plastic magnet rolls have been increasing.
このプラスチックマグネットロールは、ポリアミド、ポ
リエチレン、エチレン・酢酸ビニル・共重合体等の熱可
塑性樹脂と、ハードフェライト粉末や希土類磁石粉末等
の磁性粉とを主体とする混合物（滑剤１分散剤あるいは
可塑剤等の添加物を含むこともある）すなわち３〜５嘗
曽角の粒状に形成したコンパウンドを、射出成形機のシ
リンダーに供給し、加熱溶融して成形型内へ注入充填す
る射出成形方法（通常は異方性化のために磁場中で成形
される）によって製造するのが最も一般的な方法である
。このようなプラスチックマグネットロールは８例えば
特開昭５７−１３０４０７号、同５７−１７０５０１号
、同５９−２２６３６７号等に開示されている。This plastic magnet roll is made of a mixture consisting mainly of thermoplastic resins such as polyamide, polyethylene, ethylene/vinyl acetate, and copolymers, and magnetic powders such as hard ferrite powders and rare earth magnet powders (lubricants, dispersants, or plasticizers). In other words, the injection molding method involves supplying the compound formed into granules of 3 to 5 square meters to the cylinder of an injection molding machine, heating and melting it, and injecting it into the mold. The most common method is to mold the material in a magnetic field to create anisotropy. Such plastic magnet rolls are disclosed in, for example, Japanese Patent Laid-open Nos. 57-130407, 57-170501, and 59-226367.
第２図は最も一般的な射出成形機の要部を模式的に示す
断面図である。図において１は射出シリンダーであり、
中空円筒状に形成して一方の端部にノズル２を開口する
と共に、内部にスクリュー３を回転自在に介装する。ス
クリュー３の後端部は射出シリンダー１の後端部を貫通
して突出し。FIG. 2 is a sectional view schematically showing the main parts of the most common injection molding machine. In the figure, 1 is an injection cylinder,
It is formed into a hollow cylindrical shape, with a nozzle 2 opened at one end, and a screw 3 rotatably inserted inside. The rear end of the screw 3 protrudes through the rear end of the injection cylinder 1.
駆動シリンダー４と接続する。次に射出シリンダー１の
後端部付近にはホッパー５の開口部を接続すると共に、
射出シリンダー１の外方には加熱用のヒーター６を配設
する。Connects to drive cylinder 4. Next, the opening of the hopper 5 is connected to the vicinity of the rear end of the injection cylinder 1, and
A heater 6 for heating is arranged outside the injection cylinder 1.
以上の構成によりホッパー５中に装入したコンパウンド
を射出シリンダー１内で加熱溶融し、スクリュー３を介
してノズル２から成形型（図示せず）内に注入するので
ある。With the above configuration, the compound charged into the hopper 5 is heated and melted within the injection cylinder 1, and is injected into a mold (not shown) through the nozzle 2 via the screw 3.
上記射出成形機によって成形したプラスチックマグネッ
トロール中には、ボイドと称する気泡が発生することが
ある。このボイドが上記成形体中に発生すると１着磁し
た後の軸方向の表面磁束密度の値が不均一となり、電子
写真装置に組込んだ場合に現像性能に悪影響を及ぼすた
め不都合である。一般には４０〜５０Ｇ以下の直線性が
要求される。Air bubbles called voids may occur in the plastic magnet roll molded by the above-mentioned injection molding machine. If these voids occur in the molded article, the value of the surface magnetic flux density in the axial direction after one magnetization becomes non-uniform, which is disadvantageous because it adversely affects the developing performance when incorporated into an electrophotographic apparatus. Generally, linearity of 40 to 50 G or less is required.
上記ボイドの発生原因としては主として下記の事項が考
えれらる。The following factors are considered to be the main causes of the above-mentioned voids.
（１）原料コンパウンドからの発生ガスまたは水分（２
）成形型内における射出時の空気の巻き込み（３）射出
シリンダー内部における空気の巻き込み（４）成形凝固
冷却時のひけ
上記のうち（１）については使用原料の乾燥、（２）に
ついては成形型内の減圧脱気、（４）については溶融コ
ンパウンド注入充填後の保圧圧力の増大等によって略解
決可能である。しかしく３）については一般のプラスチ
ック成形品の成形においては、スクリューによる圧密と
背圧の作用によって略解消され得るのに対し、プラスチ
ックマグネットロールのように例えば１７〜２０ｗφＸ
３００１のような小径長尺のもので、かつ磁性粉を多量
（８０〜９０重景％）に含有するものの成形においては
脱気が完全ではなく、成形後のプラスチックマグネット
ロールにボイドが発生するという問題点がある。(1) Gas or moisture generated from the raw material compound (2)
) Air entrainment in the mold during injection (3) Air entrainment inside the injection cylinder (4) Sink during mold solidification and cooling Regarding (1) above, drying of the raw materials used, and (2) regarding the mold (4) can be almost solved by increasing the holding pressure after injection and filling of the molten compound. However, regarding 3), in the molding of general plastic molded products, it can be almost solved by the action of consolidation and back pressure by screws, whereas with plastic magnetic rolls, for example, 17 to 20 wφ
When molding small-diameter long products such as 3001 that contain a large amount of magnetic powder (80 to 90%), air removal is not complete, and voids occur in the plastic magnet roll after molding. There is a problem.
上記ボイドの発生を防止する手段として９例えば第２図
に示すように脱気用の配管７を設け、弁８を介して真空
源９と接続する。配管７の他方は射出シリンダー１とベ
ント部７ａを介して接続する。このようにして原料混合
物中の混合空気を脱気するのであるが、ベント部７ａの
設置位置は。As a means for preventing the above-mentioned voids from occurring, for example, as shown in FIG. The other end of the pipe 7 is connected to the injection cylinder 1 via a vent portion 7a. In this way, the mixed air in the raw material mixture is degassed, but the location of the vent section 7a is as follows.
原料混合物が溶融する直前であることが望ましい。It is desirable to do this immediately before the raw material mixture melts.
しかし上記設置位置の特定が極めて困難であり。However, it is extremely difficult to specify the installation location.
また仮りに特定できたとしても、原料混合物の溶融ゾー
ン自体も変動することもあって、所望の脱気を期待する
ことができない。更にまた上記配管７を射出シリンダー
１に設けることは構造を複雑にすると共に、上記ベント
部７ａから溶融物をも吸引してしまい、配管７を閉塞す
るためメンテナンスが煩雑である等の問題点がある。Furthermore, even if it could be determined, the melting zone of the raw material mixture itself may change, making it impossible to expect desired deaeration. Furthermore, providing the piping 7 in the injection cylinder 1 complicates the structure and also causes problems such as molten material being sucked through the vent portion 7a and clogging the piping 7, making maintenance complicated. be.
本発明は上記従来の技術に存在する問題点を解消し、ボ
イドの発生を防止し得るプラスチックマグネットロール
の射出成形方法を提供することを目的とするものである
。SUMMARY OF THE INVENTION An object of the present invention is to provide a method for injection molding a plastic magnet roll, which solves the problems existing in the above-mentioned conventional techniques and can prevent the generation of voids.
上記問題点の解決のために２本発明においては。 In order to solve the above problems, there are two aspects of the present invention.
熱可塑性樹脂と磁性粉とを主体とする混合物を加熱溶融
して成形型内へ充填す不プラスチックマグネットロール
の射出成形方法において、前記混合物を５００＋＋ｎ１
１ｇ以上の負圧状態で脱気溶融して成形型内へ充填する
。という技術的手段を採用したのである。In an injection molding method for a non-plastic magnetic roll in which a mixture mainly consisting of a thermoplastic resin and magnetic powder is heated and melted and filled into a mold, the mixture is heated to 50++ n1
It is degassed and melted under a negative pressure of 1 g or more and then filled into a mold. This technical method was adopted.
負圧が５００ｍ１ｇ未満では、成形後のプラスチックマ
グネットロールの表面磁束密度を均一にする作用が期待
できないため不都合である。If the negative pressure is less than 500ml/g, it is disadvantageous because the effect of making the surface magnetic flux density of the plastic magnet roll uniform after molding cannot be expected.
〔実施例〕
第１図は本発明方法の実施例における装置の要部縦断面
図であり、同一部分は前記第１図と同一の参照符号で示
す。同図において１０は配管であり、一方をホッパー５
と、他方を弁８を介して真空源９と各々接続する。１１
は密閉用のシールである。[Embodiment] FIG. 1 is a longitudinal cross-sectional view of a main part of an apparatus in an embodiment of the method of the present invention, and the same parts are designated by the same reference numerals as in FIG. 1. In the same figure, 10 is a pipe, and one side is a hopper 5.
and the other are connected to a vacuum source 9 via a valve 8. 11
is an airtight seal.
以上の構成により、ホンパー５内に原料混合物を装入後
密閉し、弁８を開いてホッパー５および射出シリンダー
１の系統全体を負圧状態とすることにより、射出シリン
ダー１内における空気若しくはガスの溶融混合物内への
巻き込みを防止することができるのである。With the above configuration, the raw material mixture is charged into the hopper 5 and then sealed, and the valve 8 is opened to bring the entire system of the hopper 5 and the injection cylinder 1 into a negative pressure state, so that the air or gas inside the injection cylinder 1 can be released. This makes it possible to prevent entrainment into the molten mixture.
平均粒径１μｍのＳｒ−フェライト粉末９０重量部とエ
チレン−エチル・アクリレート共重合体（日本ユニカー
製）１０重量部とをニーダにより２５０℃で混練し２次
いで３〜５鶴角のベレット状に粉砕してコンパウンドを
製造した。得られたコンパウンドを第１図に示す射出成
形機に装入し。90 parts by weight of Sr-ferrite powder with an average particle diameter of 1 μm and 10 parts by weight of ethylene-ethyl acrylate copolymer (manufactured by Nippon Unicar) were kneaded at 250°C in a kneader, and then ground into a pellet shape of 3 to 5 squares. A compound was produced. The obtained compound was charged into the injection molding machine shown in FIG.
ホッパー５〜射出シリンダー１を種々の条件で脱気しな
がら２７０℃の温度で溶融混練し、 ９００ｋｇ／ｃ
ｎｆの圧力でシャフトをインサートした成形用金型（図
示せず）内に射出し、約６０００ Ｇの磁場中で成形し
た。The hopper 5 to the injection cylinder 1 are melted and kneaded at a temperature of 270°C while degassing under various conditions to produce 900 kg/c.
The material was injected into a mold (not shown) into which the shaft was inserted under a pressure of nf, and molded in a magnetic field of about 6000 G.
得られた各成形体に着磁を施して、対称８極（表面磁束
密度１２００Ｇ程度）のマグネットロール（外径２０−
■、長さ２６０龍）を得た。各マグネットロールについ
て、軸方向の磁束密度分布を測定し。Each of the obtained molded bodies was magnetized, and a magnet roll (outer diameter 20-
■, length 260 dragons) was obtained. For each magnet roll, measure the magnetic flux density distribution in the axial direction.
このデータから磁力の落ち込みが４０Ｇ以上の部分の発
生数（８極全体に対するもの）を求めた。この結果を表
に示す。From this data, the number of occurrences of parts where the magnetic force drops by 40G or more (relative to all 8 poles) was determined. The results are shown in the table.
表から明らかなように、ホッパー５〜射出シリンダーｌ
の系統を５００ｍｍ１ｇ以上の負圧で脱気することによ
り、マグネットロールの表面磁束密度についての直線性
が大幅に改善されることがわかる。As is clear from the table, hopper 5 to injection cylinder l
It can be seen that the linearity of the surface magnetic flux density of the magnet roll is significantly improved by deaerating the system with a negative pressure of 500 mm/1 g or more.
本発明は以上記述したように、原材料中に混入した空気
を成形型に充填する前に完全に脱気するものであるから
、射出成形後のプラスチックマグネットロールの表面磁
束密度の値が均一となり。As described above, the present invention completely deaerates the air mixed in the raw material before filling it into the mold, so the surface magnetic flux density value of the plastic magnet roll after injection molding becomes uniform.
磁力の直線性が飛躍的に向上するという効果がある。This has the effect of dramatically improving the linearity of magnetic force.
第１図および第２図は各々本発明の実施例における装置
および従来の装置を示す要部断面図である。
ｌ：射出シリンダー、５：ホッパー、９：真空源。FIGS. 1 and 2 are sectional views of essential parts showing an apparatus according to an embodiment of the present invention and a conventional apparatus, respectively. l: injection cylinder, 5: hopper, 9: vacuum source.
Claims (1)
融して成形型内へ充填するプラスチックマグネットロー
ルの射出成形方法において、前記混合物を５００ｍｍＨ
ｇ以上の負圧状態で脱気溶融して成形型内へ充填するこ
とを特徴とするプラスチックマグネットロールの射出成
形方法。In an injection molding method for a plastic magnet roll in which a mixture mainly consisting of a thermoplastic resin and magnetic powder is heated and melted and filled into a mold, the mixture is heated to 500 mmH.
A method for injection molding a plastic magnetic roll, characterized by deaerating and melting the product under a negative pressure of more than g and filling it into a mold.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8307986A JPS62238715A (en) | 1986-04-10 | 1986-04-10 | Method for injection molding of plastic magnet roll |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8307986A JPS62238715A (en) | 1986-04-10 | 1986-04-10 | Method for injection molding of plastic magnet roll |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS62238715A true JPS62238715A (en) | 1987-10-19 |
Family
ID=13792174
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8307986A Pending JPS62238715A (en) | 1986-04-10 | 1986-04-10 | Method for injection molding of plastic magnet roll |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62238715A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5766537A (en) * | 1996-06-17 | 1998-06-16 | Chiu; Ching-Chung | Method for making a seamless tubular member |
-
1986
- 1986-04-10 JP JP8307986A patent/JPS62238715A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5766537A (en) * | 1996-06-17 | 1998-06-16 | Chiu; Ching-Chung | Method for making a seamless tubular member |
| CN1069257C (en) * | 1996-06-17 | 2001-08-08 | 邱静忠 | Seamless connected pipe producing method by adding metal powder into plastics |
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