JPS5872949A - Developer for negative charge image - Google Patents

Abstract

PURPOSE:To obtain a developer for negative charge image having good environmental stability and durability, etc., by treating silica fine powder by a resin having a property charging positively by friction between said power and conductive iron powder carrier and by using this treated silica fine powder as a toner outer adding agent. CONSTITUTION:Fine powder in which a resin is adsorbed by a method in which silica fine powder is dispersed in a solution of resin (dimethyl silicone resin, etc.) charging positively by friction between said powder and a conductive iron powder carrier and a resin is adsorbed and afterward is dried, etc. A developer in which this treated silica powder is added to a toner which does not charge by friction between said powder and the above-mentioned iron powder carrier or charges slightly positively, is prepared. The obtained developer has sufficient charging properties and a good copied image is obtained and a good image is obtained even in a low temp. and high humidity. By this way, a resin which is considered to be difficult to use conventionally and has inferior charging properties, can be used as a toner.

Description

【発明の詳細な説明】 本発明は電子写真法或い′は静電印刷法などの負電荷像
現像用の現像剤に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developer for developing negatively charged images in electrophotography or electrostatic printing.

従来、電子°写真法としては米国特許第２２９７６９１
号明細書、特公昭４２−２３９１０号公−及び特公昭４
３−２４７４８号公報等に記載されている如く多数の方
法が知られている。Conventionally, as an electrophotographic method, U.S. Patent No. 2297691
Specification, Special Publication No. 42-23910 and Special Publication No. 4
Many methods are known, as described in Japanese Patent No. 3-24748 and the like.

又、静電ｍ像をシナ−を用いて可視化する方法としては
、米国特許第２８７４０６３号明細書、同２６１８５５
２号明細書、同２２２．１７７６号明細書等に記載され
ている如く、多数の方法が知られて−る。Further, as a method for visualizing an electrostatic m-image using a mirror, US Pat. No. 2,874,063 and US Pat.
A large number of methods are known, as described in Japanese Patent No. 2, No. 222.1776, and the like.

上記現像法に用いられる現像剤は、充分な荷電性及び流
動性を得るため、トナーに荷電制御剤。The developer used in the above development method contains a charge control agent in the toner in order to obtain sufficient chargeability and fluidity.

流動性向上剤等を外添して得られることが知られている
。It is known that it can be obtained by externally adding a fluidity improver or the like.

従来、シリカ微粉末、アルｔす微粉末、カーがンブラッ
ク等！これらの目的でトナーに外添することが知られて
いる。しかしながら、これら外添剤ＫＦ１負電荷像現像
のためにトナーに正電荷を充分付与し、かつ流動性を向
上させるに適切なものがほとんどないことが本発明者ら
の研究の結果、見い出さ、れな。Conventionally, silica fine powder, Alt fine powder, carbon black, etc.! It is known to add externally to toner for these purposes. However, as a result of research by the present inventors, it has been discovered that there are almost no external additives such as KF1 suitable for imparting sufficient positive charge to the toner for developing negative charge images and improving fluidity. Na.

そのため、これまでの負電荷像用現像剤はトナー内ＭＫ
正荷電付与剤もしくは正帯電性樹脂を混入することでト
ナーそのものの正帯電性を高める仁とにより実用に付し
ていた。正荷電付与剤、もしくは正帯電性樹脂の中には
吸湿性が高い、トナー中の他の樹脂との相溶性が悪い、
現像スリーブを汚染する等の問題が多く、適当な材料を
如座に得ることが困難な状況である。Therefore, conventional negative charge image developers have MK in toner.
It has been put into practical use by incorporating a positive charge imparting agent or a positively chargeable resin to increase the positive chargeability of the toner itself. Some positive charge imparting agents or positively chargeable resins are highly hygroscopic, have poor compatibility with other resins in the toner,
There are many problems such as contamination of the developing sleeve, and it is difficult to obtain suitable materials at once.

本発明の目的は、上記欠点を解消し、トナーと外添剤と
の組み合わせにおいて良好な画像を与える負電荷像用現
像剤を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a developer for negatively charged images that eliminates the above-mentioned drawbacks and provides a good image when used in combination with a toner and an external additive.

さらに本発明の目的は、耐、久性、Ｗ４境安定性の良好
が負電荷像用現像剤を提供することにある。A further object of the present invention is to provide a developer for negatively charged images that has good durability, durability, and W4 boundary stability.

すなわち、本発明は導電性鉄粉キャリアとの摩擦で正に
帯電する樹脂で処理したシリカ微粉末を、上記キャリア
との摩擦で帯電しないかもしくは若干正に帯電するシナ
−に外部混合することを特徴とする現像剤にある。In other words, the present invention involves externally mixing fine silica powder treated with a resin that becomes positively charged by friction with a conductive iron powder carrier into a silica powder that does not become charged or becomes slightly positively charged by friction with the carrier. The characteristic is in the developer.

本発明のトナーと処理シリカ微粉末との組み合わせで得
られた現像剤は、良好な画質と耐久性を示し、又、これ
まで負電荷像用現像剤としては使用が困−とみられでき
た材料が使用可能となるなど今後の負電荷像用現像剤の
開発に対する寄与も大暑いものである。The developer obtained by combining the toner of the present invention and treated silica fine powder exhibits good image quality and durability, and is a material that has been considered difficult to use as a developer for negative charge images. It will also greatly contribute to the development of negative charge image developers in the future, as it will now be possible to use them.

本発明の現像剤に用いられるシナ−の結着樹脂としては
、トナー中の磁性体、帯電制御剤等との組み合せにおい
て鉄粉キャリアとの摩擦で帯電しないか、若干正に帯電
するような樹脂酸、いは樹脂群であれば従来知られてい
るものがすべて使用できる。又、磁性体、ｊ！１色剤等
を混入することも可能であゆ、トナーとしての帯電性が
上記条件を満足してさえいれば良い。The binder resin used in the developer of the present invention is a resin that, in combination with the magnetic material, charge control agent, etc. in the toner, does not become charged due to friction with the iron powder carrier or is slightly positively charged. All conventionally known acids or resins can be used. Also, magnetic material, j! It is also possible to mix a single coloring agent, etc., as long as the chargeability of the toner satisfies the above conditions.

本発明におけるシリカ微粉末の処理方法としては、正帯
電性樹脂を溶解した溶媒中にシリカ微粉末を分散し該樹
脂を吸着させる、シリカ微粉末に該樹脂溶液をスプレー
で吹きつきる、等積々の処理方法が可能であり、処理シ
リカの形態としては、シリカ粉の全部又は一部を該樹脂
が覆ってψる状態、該樹脂を結着剤としてシリカ粉が造
粒されている状態等の形態が採られるが、それ等のいず
れの形態も使用できる。処理シリカの粒径としてはせい
ぜいトナーと同等もしくはそれ以下とすることが望まし
い。The method for treating fine silica powder in the present invention includes dispersing the fine silica powder in a solvent in which positively charged resin is dissolved and adsorbing the resin, spraying the fine resin solution onto the fine silica powder, etc. The following treatment methods are possible, and the forms of the treated silica include a state in which the resin covers all or part of the silica powder, a state in which the silica powder is granulated using the resin as a binder, etc. Any of these forms can be used. It is desirable that the particle size of the treated silica be at most equal to or smaller than that of the toner.

シリカ微粉末量に対する該樹脂量としては、得られる処
理シリカの正帯電性がある程度大きなことが必要である
ため、シリカ微粉末１００重量部に対し５０〜３００重
量部程度が適当である。The amount of the resin relative to the amount of fine silica powder is approximately 50 to 300 parts by weight per 100 parts by weight of fine silica powder, since it is necessary that the resulting treated silica has a certain degree of positive chargeability.

トナーと処理シリカの混合量は両者の帯電性により、異
なるが、一般にトナー１００部に対し、処理シリカ１〜
１００部が良い結果を示す。The amount of mixed toner and treated silica varies depending on the charging properties of the two, but generally 1 to 100 parts of treated silica is mixed for 100 parts of toner.
100 copies shows good results.

次に実碕例を示す。Next, a practical example is shown.

実施例１ からなる平均粒径１１μのトナーを通常の方法で作製し
た。その５トナーを導電性鉄粉キャリア（日本鉄粉製Ｅ
１ｊ’Ｖ　２００〜３００メッシ、）と混合し、４００
メッシ、網を通してトナー吸引後のキャリアの電荷を測
定することにより、トナーの帯電性を調べたとξろ＋０
．８１μクーロン／Ｉと若干正であった。Example 1 A toner having an average particle size of 11 μm was prepared by a conventional method. Part 5: Toner is transferred to a conductive iron powder carrier (Nippon Iron Powder E).
1j'V 200-300 mesh,) mixed with 400
The chargeability of the toner was investigated by measuring the charge of the carrier after the toner was sucked through a mesh and a net.
．． It was slightly positive at 81 μcoulombs/I.

次に を粘性が高くなるまで混合し、風乾後、粉砕、２００メ
、シ１通過物をもって処理シリカとした。Next, the mixture was mixed until the viscosity became high, air-dried, crushed, 200 ml, and the 1-pass material was used as treated silica.

この帯電性は上記方法により、＋２．３０μＣ／Ｉであ
りた。The charging property was +2.30 μC/I by the above method.

上記トナー１００ｓと上記処理シリカ２０部をヘンシェ
ルミキサーで混合し、得られた現像剤は、２１１０紙を
ドラムに巻き付けて負電荷潜像全作るように改造された
ＮＰ−２００Ｊ複写機（キャノン製）において良好な画
像を示し、１万枚画像出し後も変化は紹められなかった
。100s of the above-mentioned toner and 20 parts of the above-mentioned treated silica were mixed in a Henschel mixer, and the resulting developer was applied to an NP-200J copier (manufactured by Canon) modified to create a negative charge latent image by wrapping 2110 paper around a drum. It showed a good image, and no change was observed even after printing 10,000 images.

実施例２ からなるトナーの帯電性は実施例と同様に測定し、Ｏ声
Ｃ／Ｉでありた。The chargeability of the toner prepared in Example 2 was measured in the same manner as in Example, and was found to be C/I.

次に からなる処理シリカを実施例１と同様に調製し、トナー
１００部に対し、１０部混合したところ、良好な画像が
得られた。A treated silica consisting of the following was prepared in the same manner as in Example 1, and when 10 parts of the treated silica was mixed with 100 parts of toner, a good image was obtained.

Claims (1)

【特許請求の範囲】 １、導電悴鉄粉キャリアとの摩擦で正に帯電する樹脂で
処理したシリカ微粉末を、上記中ヤリアとの摩擦で帯電
しないかもしくは若干正に帯電するト、ナーに外部混合
することを特徴とする負電荷像用現像剤。 ２、導電性鉄粉キャリアとの摩擦で正に帯電する樹脂が
ジメチルシリコーン樹脂である仁とを特徴とする特許請
求の範囲第１項記載の負電荷像用現像剤。[Claims] 1. Fine silica powder treated with a resin that is positively charged by friction with a conductive iron powder carrier is turned into a toner that is not charged or slightly positively charged by friction with the carrier. A negative charge image developer characterized by external mixing. 2. The developer for negatively charged images according to claim 1, wherein the resin that becomes positively charged by friction with the conductive iron powder carrier is a dimethyl silicone resin.