JP3457375B2 - Method for producing liquid developer for electrostatic image development - Google Patents
Method for producing liquid developer for electrostatic image developmentInfo
- Publication number
- JP3457375B2 JP3457375B2 JP02776294A JP2776294A JP3457375B2 JP 3457375 B2 JP3457375 B2 JP 3457375B2 JP 02776294 A JP02776294 A JP 02776294A JP 2776294 A JP2776294 A JP 2776294A JP 3457375 B2 JP3457375 B2 JP 3457375B2
- Authority
- JP
- Japan
- Prior art keywords
- liquid developer
- electrostatic image
- developer
- liquid
- pulverized
- 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
Landscapes
- Liquid Developers In Electrophotography (AREA)
Description
【発明の詳細な説明】
【0001】
【産業上の利用分野】本発明は、静電荷像の顕在化に適
用される静電荷像現像用液体現像剤の製造法に関する。
【0002】
【従来の技術】従来、電子写真法、静電記録法、静電印
刷などのプロセスに於いて静電潜像担持体上に形成され
た静電荷像を現像する方法には液体現像剤を使う液体現
像法と、粉体現像剤を使う乾式現像法が知られている。
液体現像法は、現像剤に有機溶剤を多量に使用するため
一般事務用には溶剤蒸気拡散等の問題から不適であり、
近年ではその取り扱い易さから乾式現像法が主流になっ
ている。しかしながら、乾式現像法は粉体現像剤(トナ
ー)粒子径が10μ程度とかなり粗大なために、高精細
な画像を得るという点で限界が生じてきている。一方、
液体現像法では現像剤粒子(以下トナーと呼ぶ)が粉体
トナーに比べて極めて微細であるために、近年の市場動
向である高画質化が可能であり、その長所が見直されて
きている。
【0003】液体現像法に用いられる現像剤(以下液体
現像剤と呼ぶ)は、電気絶縁性の有機溶剤(キャリア液
体)中に着色微粉体を懸濁させたものであり、その粒子
径の小ささにより、乾式現像法に比較して細線再現性が
良く、なお且つハイコントラストの画像を得る事がで
き、またイエロー、マゼンタ、シアン、ブラックの4色
のトナーを用いたフルカラー現像においてもその特徴を
発揮し高解像度、高階調の画質を得られる。
【0004】液体現像剤の製造方法としては、例えば特
開昭61−180248号公報に記載されている方法が
ある。これは、40℃以下では無極性溶媒に不溶性であ
り、50℃を超えると該無極性溶媒に溶媒和する性質を
有する熱可塑性樹脂を、一旦該無極性溶媒に溶媒和させ
た後冷却することにより微細な熱可塑性樹脂微粒子を形
成し、該樹脂微粒子溶媒分散体を、顔料、分散剤、無極
性溶媒と共に湿式粉砕し液体現像剤を製造する方法であ
る。
【0005】しかしながら、該樹脂微粒子溶媒分散体に
は以下の様な問題点がある。
1.溶媒分離を起こしやすく、不均一になりやすい。
2.生産効率が悪い。例えば、25Kgの樹脂を微粒子
分散体にするには、10時間を要する。
【0006】
【発明が解決しようとする課題】本発明は、液体現像剤
を、効率的かつ安定して得るための製造方法に関する。
【0007】
【課題を解決するための手段】本発明は、液体現像剤の
バインダー成分として、樹脂微粒子溶媒分散体の代わり
に、低温凍結法で機械粉砕した熱可塑性樹脂を用いる事
を特徴とする、液体現像剤の製造方法に関する。該低温
凍結粉砕樹脂は均一であり、かつ粉砕業者で大量に低コ
ストで処理できる為、樹脂微粒子溶媒分散工程を省略で
きるメリットは大きい。
【0008】以下、本発明について詳細に説明する。熱
可塑性樹脂を液体窒素(−196℃)雰囲気中で低温凍
結粉砕し、その後分級機により粗大粒子を除去する。次
に該低温凍結粉砕樹脂、着色剤、無極性溶媒および添加
剤を混合し、湿式粉砕機で所定の粒子径まで粉砕する。
【0009】本発明に於いて用いられる熱可塑性樹脂と
しては、エチル酢酸ビニル共重合体、エチレン系共重合
体、アクリル系共重合体(エチレンエチルアクリレー
ト、エチレンビニルアセテート、ポリブチルメタクリレ
ート、ポリエチルメタクリレート、ポリメチルメタクリ
レート等)等が適している。なお、熱可塑性樹脂は1種
類だけでも、互いに相溶性のある2種類以上の異なった
種類の樹脂の混合物であっても差し支えない。
【0010】本発明に於いて用いられる低温凍結粉砕シ
ステムについて説明する。一般に粒状の熱可塑性樹脂を
常温で粉砕するのは困難である。しかし樹脂及びターボ
ミル等の粉砕機を液体窒素で−196℃に冷却し、樹脂
の低温脆性を利用して粉砕することにより、500ミク
ロン以下に微粉砕することができる。また低温凍結粉砕
後、分級機で適度な粒径に分級し、粗大粒子を除去すれ
ば、次工程の湿式粉砕における粉砕効率が向上する。
【0011】本発明に於いて用いられる着色剤として
は、通常使用されている顔料や染料が使用でき、例えば
ハンザイエロー、ジスアゾイエロー、キノリンイエロ
ー、パーマネントイエロー、ベンジジンオレンジ、ベン
ガラ、ファーストレッド、リソールレッド、パーマネン
トレッド、ウォッチャンレッドカルシウム塩、ウォッチ
ャンレッドマンガン塩、ピラゾロンレッド、レーキレッ
ドC、レーキレッドD、ブリリアントカーミン3Bまた
は6B、紺青、フタロシアニンブルー、ビクトリアブル
ー、ニグロシン、カーボンブラック等の顔料、或いは染
料を単独で、或いは混合して使用できる。
【0012】本発明に於いて用いられる無極性溶媒は、
誘電率が3.0以下で電気絶縁性(体積固有抵抗109
Ωcm以上)の炭化水素系溶剤、好ましくは分岐鎖状脂
肪族炭化水素が用いられる。このような特性を有する無
極性溶媒としては、エクソン化学(株)製のアイソパー
(商品名)が最も一般的であり、更に詳しくはアイソパ
ーG,アイソパーH、アイソパーL等が最も好ましい
が、特にこれらに限定されるものではない。その他の溶
剤としては、場合によってはごく微量添加するものも含
めて、例えばシェル社製シェルゾールA、AB(商品
名)、日本石油(株)製ナフテゾルL、M、H(商品
名)等が挙げられる。
【0013】本発明に於いて用いられる添加剤として
は、各種分散助剤、電荷付与剤等が用いられる。
【0014】以上の原材料を混合し、湿式粉砕機で粒径
が3ミクロン以下になるまで粉砕する。本発明に於いて
用いられる湿式粉砕機としては、アトライター、サンド
ミル、ダイノミル、ボールミル、アペックスミル、スパ
イクミル、コボールミル、ダイヤモンドファインミル等
のメジア型湿式粉砕機、あるいはホモジナイザー、マイ
コロイダー、トリゴナル、スラッシャー、コロイドミ
ル、キャビトロン、ゴラトール等のメジアレス型湿式粉
砕機が挙げられる。
【0015】
【実施例】以下、実施例に基づいて本発明を説明する。
なお、粒径測定は、粒度分布測定装置(SA−CP3
L、島津製作所製)で測定した。また、画像評価は、不
揮発分1.5%に希釈した現像液を用い、液体現像複写
機(Savin870,セイビン社製)にて得られた印
字物で行った。例中、部とあるのは、重量部を示す。
【0016】〔実施例1〕
ニュクレルN410(商品名、三井デュポンポリケミカ
ル(株)エチレン−メタクリル酸共重合体 軟化点78
℃)を液体窒素雰囲気中にて冷凍粉砕を行った。得られ
た粉砕品の粒径は、250μ以下であった。
エチレン−メタクリル酸共重合体冷凍粉砕品 15部
リオノールイエローFG1310
(商品名、黄色顔料:東洋インキ製造(株)製) 3部
アイソパーH(エクソン社製) 100部
分散助剤 0.5部
上記混合物を2Lアトライターで10時間湿式粉砕し、
平均粒径2μの液体現像剤を得た。
【0017】得られた液体現像剤を、アイソパーHで不
揮発分1.5%まで希釈し、その希釈液1000部に対
し1.0部の割合でレシチンを添加し画像試験を行った
ところ、両方共反射濃度(反射濃度計、マクベスRD−
918使用)1.0以上の、地汚れの無い良好な画像が
得られた。
〔実施例2〕エバフレックス P−1403(商品名、
三井ポリケミカル(株)エチレン酢酸ビニル 軟化点7
0℃)を液体窒素雰囲気中にて冷凍粉砕を行った。得ら
れた粉砕品の粒径は,450μ以下であった。
エチレン−メタクリル酸共重合体冷凍粉砕品 15部
リオノールブルーFG7310
(商品名、青色顔料:東洋インキ製造(株)製) 3部
アイソパーH(エクソン社製) 100部
分散助剤 0.5部
上記混合物を2Lアトライターで10時間湿式粉砕し,
平均粒径2μの液体現像剤を得た。
【0018】得られた液体現像剤を、アイソパーHで不
揮発分1.5%まで希釈し、その希釈液1000部に対
し1.0部の割合でレシチンを添加し画像試験を行った
ところ、両方共反射濃度(反射濃度計、マクベスRD−
918使用)1.0以上の、地汚れの無い良好な画像が
得られた。
【0019】
【発明の効果】本発明によれば、バインダー成分に低温
凍結粉砕樹脂を使用すれば、効率的かつ安定的に、液体
現像剤を製造することができる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a liquid developer for developing an electrostatic image, which is applied to visualizing an electrostatic image. [0002] Conventionally, a method for developing an electrostatic image formed on an electrostatic latent image carrier in processes such as electrophotography, electrostatic recording, and electrostatic printing has been known as liquid development. A liquid developing method using a developer and a dry developing method using a powder developer are known.
The liquid developing method uses a large amount of an organic solvent as a developer, and is unsuitable for general office work due to problems such as solvent vapor diffusion.
In recent years, dry development has become the mainstream because of its ease of handling. However, the dry development method has a limit in obtaining a high-definition image because the powder developer (toner) has a rather coarse particle diameter of about 10 μm. on the other hand,
In the liquid developing method, since developer particles (hereinafter referred to as toner) are extremely fine compared to powder toner, high image quality, which is a market trend in recent years, is possible, and its advantages are being reviewed. [0003] A developer used in the liquid developing method (hereinafter referred to as a liquid developer) is a suspension of colored fine powder in an electrically insulating organic solvent (carrier liquid). As a result, fine line reproducibility is better and a high-contrast image can be obtained as compared with the dry development method, and the characteristic is also obtained in full-color development using four color toners of yellow, magenta, cyan and black. And high resolution and high gradation image quality can be obtained. As a method for producing a liquid developer, for example, there is a method described in JP-A-61-180248. This means that a thermoplastic resin having a property of being insoluble in a nonpolar solvent at a temperature of 40 ° C. or less and solvating the nonpolar solvent at a temperature exceeding 50 ° C. is once solvated with the nonpolar solvent and then cooled. This method is a method for producing a liquid developer by forming finer thermoplastic resin fine particles, and wet-grinding the resin fine particle solvent dispersion together with a pigment, a dispersant, and a nonpolar solvent. However, the resin fine particle solvent dispersion has the following problems. 1. It is easy to cause solvent separation and tends to be non-uniform. 2. Poor production efficiency. For example, it takes 10 hours to convert 25 kg of resin into a fine particle dispersion. [0006] The present invention relates to a manufacturing method for efficiently and stably obtaining a liquid developer. The present invention is characterized in that a thermoplastic resin mechanically pulverized by a low-temperature freezing method is used as a binder component of a liquid developer instead of a solvent dispersion of fine resin particles. And a method for producing a liquid developer. Since the low-temperature freeze-pulverized resin is uniform and can be processed in a large amount at low cost by a pulverizer, there is a great merit that the resin fine particle solvent dispersion step can be omitted. Hereinafter, the present invention will be described in detail. The thermoplastic resin is freeze-pulverized at a low temperature in a liquid nitrogen (-196 ° C) atmosphere, and then coarse particles are removed by a classifier. Next, the low-temperature freeze-pulverized resin, the colorant, the nonpolar solvent and the additive are mixed and pulverized to a predetermined particle size by a wet pulverizer. The thermoplastic resin used in the present invention includes ethyl vinyl acetate copolymer, ethylene copolymer, and acrylic copolymer (ethylene ethyl acrylate, ethylene vinyl acetate, polybutyl methacrylate, polyethyl methacrylate). , Polymethyl methacrylate, etc.) are suitable. The thermoplastic resin may be only one kind or a mixture of two or more different kinds of resins compatible with each other. The low-temperature freeze-pulverization system used in the present invention will be described. Generally, it is difficult to pulverize a granular thermoplastic resin at room temperature. However, a resin and a pulverizer such as a turbo mill are cooled to -196 ° C. with liquid nitrogen and pulverized by utilizing the low-temperature brittleness of the resin, whereby the pulverization can be performed to 500 μm or less. After low-temperature freeze-pulverization, if the particles are classified to an appropriate particle size by a classifier to remove coarse particles, the pulverization efficiency in the next step of wet pulverization is improved. As the colorant used in the present invention, commonly used pigments and dyes can be used. For example, Hansa Yellow, Disazo Yellow, Quinoline Yellow, Permanent Yellow, Benzidine Orange, Bengala, Fast Red, Lisor Red Pigments such as, permanent red, watch red calcium salt, watch red manganese salt, pyrazolone red, lake red C, lake red D, brilliant carmine 3B or 6B, navy blue, phthalocyanine blue, victoria blue, nigrosine, carbon black, or Dyes can be used alone or in combination. The non-polar solvent used in the present invention is:
Electrical insulation with a dielectric constant of 3.0 or less (volume resistivity 10 9
Ωcm or more), preferably a branched aliphatic hydrocarbon. The most common nonpolar solvent having such properties is Isopar (trade name) manufactured by Exxon Chemical Co., Ltd. More specifically, Isopar G, Isopar H, Isopar L, and the like are most preferable. However, the present invention is not limited to this. Other solvents, including those that are added in very small amounts in some cases, include, for example, Shell Sol A and AB (trade names) manufactured by Shell Co., Ltd., and Naphtesol L, M, H (trade names) manufactured by Nippon Oil Co., Ltd. No. As the additives used in the present invention, various dispersing aids, charge imparting agents and the like are used. The above raw materials are mixed and pulverized by a wet pulverizer until the particle size becomes 3 μm or less. Examples of the wet pulverizer used in the present invention include a medial wet pulverizer such as an attritor, a sand mill, a dyno mill, a ball mill, an apex mill, a spike mill, a coball mill, and a diamond fine mill, or a homogenizer, a mycolloider, a trigonal, and a slasher. , Colloid mills, Cavitron, Golator and the like. Hereinafter, the present invention will be described with reference to examples.
The particle size was measured using a particle size distribution analyzer (SA-CP3
L, manufactured by Shimadzu Corporation). The image evaluation was performed on a printed matter obtained by a liquid developing copier (Savin 870, manufactured by Sabin Co.) using a developer diluted to a nonvolatile content of 1.5%. In the examples, “parts” means “parts by weight”. Example 1 Nuclel N410 (trade name, Mitsui DuPont Polychemical Co., Ltd. ethylene-methacrylic acid copolymer, softening point 78)
° C) in a liquid nitrogen atmosphere. The particle size of the obtained pulverized product was 250 μ or less. Ethylene-methacrylic acid copolymer frozen and crushed product 15 parts Lionol Yellow FG1310 (trade name, yellow pigment: manufactured by Toyo Ink Mfg. Co., Ltd.) 3 parts Isopar H (manufactured by Exxon) 100 parts Dispersing aid 0.5 part The mixture is wet-ground with a 2L attritor for 10 hours,
A liquid developer having an average particle size of 2 μ was obtained. The obtained liquid developer was diluted with Isopar H to a nonvolatile content of 1.5%, and lecithin was added at a ratio of 1.0 part to 1,000 parts of the diluted solution, and an image test was performed. Co-reflection density (reflection densitometer, Macbeth RD-
918), and a good image free of background stains of 1.0 or more was obtained. Example 2 Evaflex P-1403 (trade name,
Mitsui Polychemicals Co., Ltd. Ethylene vinyl acetate Softening point 7
(0 ° C.) in a liquid nitrogen atmosphere. The particle size of the obtained pulverized product was 450 μm or less. Ethylene-methacrylic acid copolymer frozen pulverized product 15 parts Lionol Blue FG7310 (trade name, blue pigment: manufactured by Toyo Ink Mfg. Co., Ltd.) 3 parts Isopar H (manufactured by Exxon) 100 parts Dispersing aid 0.5 part The mixture is wet-ground with a 2L attritor for 10 hours,
A liquid developer having an average particle size of 2 μ was obtained. The obtained liquid developer was diluted with Isopar H to a nonvolatile content of 1.5%, and lecithin was added at a ratio of 1.0 part to 1,000 parts of the diluted solution, and an image test was performed. Co-reflection density (reflection densitometer, Macbeth RD-
918), and a good image free of background stains of 1.0 or more was obtained. According to the present invention, if a low-temperature freeze-ground resin is used as a binder component, a liquid developer can be efficiently and stably produced.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平6−289657(JP,A) 特開 平2−241787(JP,A) 特開 平4−13728(JP,A) (58)調査した分野(Int.Cl.7,DB名) G03G 9/12 - 9/13 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-289657 (JP, A) JP-A-2-241787 (JP, A) JP-A-4-13728 (JP, A) (58) Field (Int.Cl. 7 , DB name) G03G 9/12-9/13
Claims (1)
砕した粒径500μ以下の熱可塑性樹脂を用い、着色
剤、無極性溶媒および添加剤と共に湿式粉砕する事を特
徴とする静電荷像現像用液体現像剤の製造方法。(57) [Claims 1] A binder is made of a thermoplastic resin having a particle size of 500 μm or less mechanically pulverized by a low-temperature freeze-pulverization method and wet-pulverized together with a coloring agent, a nonpolar solvent and additives. A method for producing a liquid developer for developing an electrostatic image, characterized by comprising:
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP02776294A JP3457375B2 (en) | 1994-02-25 | 1994-02-25 | Method for producing liquid developer for electrostatic image development |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP02776294A JP3457375B2 (en) | 1994-02-25 | 1994-02-25 | Method for producing liquid developer for electrostatic image development |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH07234551A JPH07234551A (en) | 1995-09-05 |
JP3457375B2 true JP3457375B2 (en) | 2003-10-14 |
Family
ID=12230026
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP02776294A Expired - Fee Related JP3457375B2 (en) | 1994-02-25 | 1994-02-25 | Method for producing liquid developer for electrostatic image development |
Country Status (1)
Country | Link |
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JP (1) | JP3457375B2 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0845712B1 (en) * | 1996-06-20 | 2004-12-08 | Mitsubishi Chemical Corporation | Pigment composition for liquid toner |
JP4752296B2 (en) | 2005-03-09 | 2011-08-17 | セイコーエプソン株式会社 | Method for producing liquid developer and liquid developer |
JP2007177113A (en) * | 2005-12-28 | 2007-07-12 | Teijin Techno Products Ltd | Organic macromolecular polymer fine particle and method for producing the same |
JP2008310052A (en) * | 2007-06-14 | 2008-12-25 | Seiko Epson Corp | Liquid developer and image forming apparatus |
-
1994
- 1994-02-25 JP JP02776294A patent/JP3457375B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
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JPH07234551A (en) | 1995-09-05 |
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