JPH0812448B2 - Electrophotographic developer - Google Patents
Electrophotographic developerInfo
- Publication number
- JPH0812448B2 JPH0812448B2 JP1078013A JP7801389A JPH0812448B2 JP H0812448 B2 JPH0812448 B2 JP H0812448B2 JP 1078013 A JP1078013 A JP 1078013A JP 7801389 A JP7801389 A JP 7801389A JP H0812448 B2 JPH0812448 B2 JP H0812448B2
- Authority
- JP
- Japan
- Prior art keywords
- hydrophobic silica
- toner
- charge amount
- carrier
- developer
- 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
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は電子写真法に使用される乾式二成分現像剤に
関し、とくに負帯電性のトナーを構成する電子写真用現
像剤に関する。The present invention relates to a dry two-component developer used in electrophotography, and more particularly to an electrophotographic developer that constitutes a negatively chargeable toner.
電子写真用現像剤（以下現像剤と称す）は通常、結着
樹脂、電荷制御剤、着色剤、その他必要に応じて添加さ
れる添加剤を所定の配合にドライブレンドした後、溶融
混練、粉砕、分級工程を経てトナー化し、鉄粉などのキ
ャリア粒子と混合し作製している。A developer for electrophotography (hereinafter referred to as a developer) is usually a binder resin, a charge control agent, a colorant, and other additives that are optionally added after dry blending into a predetermined composition, and then melt kneading and pulverizing. The toner is made into a toner through a classification process, and mixed with carrier particles such as iron powder.
このような現像剤において良好な画質の可視画像を形
成するためには、トナーが高い流動性を有し、かつ均一
な帯電性を有することが必要であり、そのために従来よ
り疎水性シリカをトナーに添加混合することが行なわれ
ている。In order to form a visible image with good image quality in such a developer, it is necessary that the toner has high fluidity and uniform chargeability. Is added to and mixed with.
しかしながら、従来技術による疎水性シリカは、周囲
の環境によりその帯電量が変化しやすいために必然的に
トナーに対して環境依存性を生じさせるという問題を有
していた。すなわち、疎水性シリカをトナーに添加した
現像剤を10℃/15％RHという低温低湿環境下において使
用すると、疎水性シリカとキャリアの帯電量が20℃/65
％RHの常温常湿環境下と比較して著しく高くなる結果、
トナーの帯電量も高くなる為、画像濃度が低下するとい
う問題を生ずるものであった。一方、30℃/85％RHとい
う高温高湿環境下においては、疎水性シリカとキャリア
の帯電量が常温常湿環境下より著しく低いものとなり、
結果的にトナーの帯電量を低下させる。ゆえに画像濃度
が必要以上に高くなり階調性の悪い複写画像となった
り、トナー消費量の増加、トナー飛散の増大、地カブリ
の発生等の問題が生じていた。However, the hydrophobic silica according to the conventional technique has a problem that the charge amount of the toner tends to change depending on the surrounding environment, and thus the toner is necessarily environmentally dependent. That is, when a developer in which hydrophobic silica is added to the toner is used in a low temperature and low humidity environment of 10 ° C / 15% RH, the charge amount of the hydrophobic silica and the carrier is 20 ° C / 65%.
As a result of being significantly higher than in a room temperature and normal humidity environment of% RH,
Since the charge amount of the toner also becomes high, there arises a problem that the image density is lowered. On the other hand, in the high temperature and high humidity environment of 30 ° C / 85% RH, the charge amount of the hydrophobic silica and the carrier becomes significantly lower than that in the normal temperature and normal humidity environment.
As a result, the toner charge amount is reduced. Therefore, there have been problems that the image density becomes unnecessarily high, resulting in a copy image having poor gradation, an increase in toner consumption, an increase in toner scattering, and a background fog.
本発明は上記の事情に鑑みてなされたものであり、周
囲の環境により画像濃度が変化することなく、トナー飛
散、地カブリが少なく、更に複写耐久性に優れた現像剤
を提供することを目的とする。The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a developer that does not change the image density depending on the surrounding environment, has less toner scattering and background fog, and is excellent in copy durability. And
本発明者は、前記問題点を改良すべく鋭意研究を重ね
た結果、キャリアとの組合せにおいて特定の飽和帯電量
となるよう疎水性シリカを選択してトナーに付着させた
ものを現像剤に使用することにより前記問題点が著しく
改善されることを見出し本発明に至った。The present inventor has conducted extensive studies to improve the above-mentioned problems, and as a result, used a developer in which hydrophobic silica was selected so as to have a specific saturated charge amount in combination with a carrier and attached to a toner. It was found that the above problems can be remarkably improved by doing so, and the present invention has been accomplished.
すなわち本発明の電子写真用現像剤の１つは、負帯電
性トナーと、該負帯電性トナーに付着してなる疎水化度
が50％以上であり且つBET比表面積が180m2/g以下の疎水
性シリカと、キャリアからなる現像剤であって、前記キ
ャリアに対する疎水性シリカの飽和帯電量が−300〜＋2
00μc/gであることを特徴とする電子写真用現像剤であ
る。That is, one of the electrophotographic developers of the present invention comprises a negatively chargeable toner, a hydrophobicity of 50% or more formed by adhering to the negatively chargeable toner, and a BET specific surface area of 180 m 2 / g or less. A developer comprising a hydrophobic silica and a carrier, wherein the saturated charge amount of the hydrophobic silica with respect to the carrier is -300 to +2.
It is a developer for electrophotography, which is characterized in that it is 00 μc / g.
以下に本発明の構成を詳細に説明する。 The configuration of the present invention will be described in detail below.
まず、本発明の主たる構成要素である疎水性シリカと
しては、ジメチルジクロルシラン、トリメチルクロルシ
ラン、メチルトリクロルシラン、アリルフェニルジクロ
ルシラン、ベンジルジメチルクロルシラン、ブロムメチ
ルジメチルクロルシラン、Ｐ−クロルフェニルトリクロ
ルシラン、３−クロルプロピルトリメトキシシラン、ビ
ニルトリエトキシシラン、ビニルトリアセトキシシラ
ン、ジビニルクロルシラン等の疎水化剤、特にジメチル
ジクロルシランあるいはヘキサメチレンジシラザンで処
理されたコロイド状の二酸化ケイ素であって、50％以上
の疎水化度と180m2/g以下のBET比表面積とキャリアに対
する飽和帯電量が−300〜＋200μc/gのものが本発明に
適用される。First, as the hydrophobic silica which is the main component of the present invention, dimethyldichlorosilane, trimethylchlorosilane, methyltrichlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, P-chlorophenyl. Hydrophobizing agents such as trichlorosilane, 3-chloropropyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, and divinylchlorosilane, especially colloidal silicon dioxide treated with dimethyldichlorosilane or hexamethylenedisilazane. Therefore, those having a hydrophobicity of 50% or more, a BET specific surface area of 180 m 2 / g or less and a saturated charge amount with respect to the carrier of −300 to +200 μc / g are applied to the present invention.
この場合における飽和帯電量は組合せるキャリアとの
相対的な測定値がこの数値限定の範囲内に入るよう上記
の疎水性シリカの中から選択して本発明に適用される。The saturated charge amount in this case is applied to the present invention by selecting from the above-mentioned hydrophobic silica so that the measured value relative to the carrier to be combined falls within the range of this numerical limitation.
ここで本発明でいう疎水化度とは、別名メタノールウ
ェッタビリティー値（MW値）ともいい、疎水性シリカの
表面の疎水性を表わす尺度として一般に用いられている
ものである。該疎水化度の測定方法は次のようにして行
う。まず、疎水性シリカ0.2gを250ccのフラスコに入
れ、これに水を50cc添加する。次にマグネチックスター
ラーで上記水中における疎水性シリカを攪拌しながら、
メタノールをビューレットから滴下する。疎水性シリカ
の全量がメタノールによって湿潤し、水とメタノールの
混合系に良分散したと目視によって判断した時にメタノ
ールの滴下を止める。この時の水とメタノールの混合相
中におけるメタノールの重量を百分率であらわし、この
数値を疎水化度とする。Here, the degree of hydrophobicity referred to in the present invention is also known as methanol wettability value (MW value), and is generally used as a measure of the hydrophobicity of the surface of hydrophobic silica. The method for measuring the degree of hydrophobicity is as follows. First, 0.2 g of hydrophobic silica is put in a 250 cc flask, and 50 cc of water is added thereto. Next, while stirring the hydrophobic silica in the water with a magnetic stirrer,
Methanol is dripped from the buret. When it is visually judged that the hydrophobic silica is completely wet with methanol and well dispersed in the mixed system of water and methanol, the dropping of methanol is stopped. The weight of methanol in the mixed phase of water and methanol at this time is expressed as a percentage, and this value is taken as the degree of hydrophobicity.
次に本発明でいう飽和帯電量について説明する。一般
にキャリアと疎水性シリカをある一定の力で持続的に攪
拌混合すると疎水性シリカの帯電量は時間と共に、負帯
性シリカの場合は負極性側に、正帯性シリカの場合は正
極性側に上昇していく。しかしながら、疎水性シリカの
帯電量は時系列上ある時点で最大となり、それ以後は低
下するという挙動を示す。本発明においては、この最大
となる帯電量を飽和帯電量とする。具体的には以下のよ
うな測定方法により飽和帯電量を求めた。すなわち、常
温常湿（20℃/65％RH）の環境条件に20時間放置したキ
ャリア199.6gとシリカ0.4gを250ccのポリビンに入れ、
定回転の回転装置に該ポリビンを設置した後回転させ混
合攪拌を行う。上記のように混合攪拌する過程におい
て、疎水性シリカの帯電量をブローオフ帯電量測定装置
にて初期より５分おきに３回ずつ測定し、３回の平均値
をその時の攪拌時間における帯電量とする。このように
測定された帯電量のうち最大の帯電量を飽和帯電量とす
る。Next, the saturated charge amount in the present invention will be described. Generally, when the carrier and hydrophobic silica are continuously stirred and mixed with a certain force, the charge amount of the hydrophobic silica changes with time, the negative polarity side is negative in the case of negative band silica, and the positive polarity side is in the case of normal band silica. Rises to. However, the charge amount of the hydrophobic silica has a behavior that it becomes maximum at a certain point in time series and decreases thereafter. In the present invention, the maximum charge amount is the saturated charge amount. Specifically, the saturated charge amount was determined by the following measuring method. That is, 199.6 g of carrier and 0.4 g of silica, which had been left for 20 hours under normal temperature and humidity (20 ° C / 65% RH), were placed in a 250 cc polybin,
The polybin is placed on a rotating device of constant rotation and then rotated to mix and stir. In the process of mixing and stirring as described above, the charge amount of the hydrophobic silica was measured 3 times every 5 minutes from the initial stage by the blow-off charge amount measuring device, and the average value of 3 times was taken as the charge amount in the stirring time at that time. To do. The maximum charge amount of the charge amounts measured in this way is defined as the saturated charge amount.
本発明では疎水性シリカの飽和帯電量が−300〜＋200
μc/gである疎水性シリカとキャリアの組合せであって
も、疎水性シリカの疎水化度が50％より小さい場合、あ
るいはBET比表面積が180m2/gよりも大きい場合には高温
高湿環境下において、トナーの帯電量が低下しやすく、
トナー消費量の増加や地カブリ、トナー飛散の発生とい
う問題を生じる。In the present invention, the saturated charge amount of the hydrophobic silica is -300 to +200.
Even in a combination of hydrophobic silica and carrier with μc / g, if the hydrophobicity of hydrophobic silica is less than 50%, or if the BET specific surface area is greater than 180 m 2 / g, high temperature and high humidity environment Below, the charge amount of the toner easily decreases,
This causes problems such as an increase in toner consumption, background fogging, and toner scattering.
また、疎水性シリカの飽和帯電量が−300μc/gより負
極性側のものは低温低湿環境下においてトナーの帯電量
が上昇し画像濃度が低下するという問題を生じる。一
方、飽和帯電量が＋200μc/gより正極性側のものは低温
低湿環境下においてトナーの帯電量が低下し地カブリ、
トナー飛散の問題が発生する。Further, when the saturated charge amount of the hydrophobic silica is on the negative side of -300 μc / g, there is a problem that the charge amount of the toner increases and the image density decreases in a low temperature and low humidity environment. On the other hand, when the saturated charge amount is more than +200 μc / g on the positive polarity side, the charge amount of the toner decreases in a low temperature and low humidity environment and the background fog
The problem of toner scattering occurs.
次に、本発明の電子写真用現像剤の別の１つは、負帯
電性トナーと、該負帯電性トナーに付着してなる疎水化
度が50％以上である且つBET比表面積が180m2/g以下の疎
水性シリカＡおよび疎水化度が50％以上の疎水性シリカ
Ｂの混合物と、キャリアからなる現像剤であって、 （Ａ）前記キャリアに対する疎水性シリカＡの飽和帯電
量が−300〜＋200μc/gであり、 （Ｂ）前記キャリアに対する疎水性シリカＢの飽和帯電
量が−300μc/gより負極性側に高い関係を有し、 （Ｃ）疎水性シリカＡに対する疎水性シリカＢの配合比
率が50重量％以下であることを特徴とする電子写真用現
像剤である。Next, another one of the developers for electrophotography of the present invention is a negatively chargeable toner, and a degree of hydrophobicity formed by adhering to the negatively chargeable toner is 50% or more and a BET specific surface area of 180 m 2 A developer comprising a carrier and a mixture of a hydrophobic silica A having a hydrophobicity of 50 g / g or less and a hydrophobic silica B having a hydrophobicity of 50% or more, wherein the saturated charge amount of the hydrophobic silica A with respect to the carrier is − 300 to +200 μc / g, (B) the saturated charge amount of the hydrophobic silica B with respect to the carrier is higher than that of −300 μc / g on the negative polarity side, and (C) the hydrophobic silica B with respect to the hydrophobic silica A. Is a developer for electrophotography, characterized in that the compounding ratio thereof is 50% by weight or less.
本発明において疎水性シリカＡに対する疎水性シリカ
Ｂの配合比率が50％を越えると低温低湿環境下において
トナーの帯電量が上昇し、画像濃度が低下するという問
題を生ずる。In the present invention, when the blending ratio of the hydrophobic silica B to the hydrophobic silica A exceeds 50%, the toner charge amount increases in a low temperature and low humidity environment, and the image density decreases.
本発明における疎水性シリカをトナーの表面に付着さ
せる手段としては、Ｖ型混合機、タービン型攪拌機、ヘ
ンシェルミキサー等の一般的な混合機を用い、トナー粒
子の表面にまぶしいといわれる弱い状態で付着させる方
法と共に、機械的な衝撃力により芯材の表面に微粉体の
一部を埋没又は熱融着等により強固に付着させることが
できる表面改質装置を使用してトナー粒子の表面に疎水
性シリカを付着させてもよい。As a means for adhering the hydrophobic silica to the surface of the toner in the present invention, a general mixer such as a V-type mixer, a turbine-type stirrer, or a Henschel mixer is used, and it adheres to the surface of the toner particles in a weak state which is said to be dazzling. In addition to the above method, the surface of the toner particles is made hydrophobic by using a surface modification device that can firmly attach a part of the fine powder to the surface of the core material by burying or heat fusion with the mechanical impact force. Silica may be attached.
トナー粒子の表面に付着させる疎水性シリカの量は、
低温低湿あるいは高温高湿においての現像物性を良好に
保つために、0.05〜１重量％であることが好ましい。The amount of hydrophobic silica attached to the surface of the toner particles is
The content is preferably 0.05 to 1% by weight in order to keep good development properties at low temperature and low humidity or high temperature and high humidity.
次に本発明を構成する負帯電性トナーおよびキャリア
について説明する。Next, the negatively chargeable toner and carrier constituting the present invention will be described.
負帯電性トナーは、スチレン樹脂、ポリアクリル酸エ
ステル樹脂、スチレン−アクリル酸エステル共重合体樹
脂、ポリエステル樹脂等の熱可塑性樹脂を主成分とし、
カーボンブラック、その他の顔料および染料からなる着
色剤、含金属錯塩染料、オイルブラック、脂肪酸の金属
塩等の負帯電性を与える電荷制御剤およびポリテトラフ
ルオロエチレン粉、低分子量ポリプロピレン等の潤滑
剤、定着剤等の添加物を所定の配合比で混合後、溶融混
練し然るのち冷却後粉砕分級して得られる。The negatively chargeable toner contains a thermoplastic resin such as a styrene resin, a polyacrylic acid ester resin, a styrene-acrylic acid ester copolymer resin, a polyester resin as a main component,
Carbon black, colorants composed of other pigments and dyes, metal-containing complex dyes, oil blacks, charge control agents that impart negative chargeability such as metal salts of fatty acids, and lubricants such as polytetrafluoroethylene powder and low molecular weight polypropylene, It is obtained by mixing additives such as a fixing agent in a predetermined mixing ratio, melt-kneading them, cooling them, and pulverizing and classifying them.
また、キャリアとしては、鉄粉、フェライト、造粒マ
グネタイトおよびそれらをシリコーン系樹脂、アクリル
系樹脂、フッ素系樹脂、エポキシ系樹脂等の樹脂にてコ
ートしたコーティングキャリア等、通常現像剤に使用さ
れるキャリアの中からトナーへの帯電付与および疎水性
シリカとの飽和帯電量が所望の範囲内になるよう適宜選
択して使用することができる。Further, as the carrier, iron powder, ferrite, granulated magnetite and a coating carrier obtained by coating them with a resin such as a silicone resin, an acrylic resin, a fluorine resin, an epoxy resin, etc. are usually used for developers. The carrier can be appropriately selected and used so that the charge imparting to the toner from the carrier and the saturated charge amount with the hydrophobic silica are within a desired range.
次に本発明を実施例により具体的に説明する。なお、
本発明はその要旨をこえない限り以下の実施例に限定さ
れるものではない。Next, the present invention will be specifically described with reference to examples. In addition,
The present invention is not limited to the following examples unless it exceeds the gist.
〈実施例１〜４、比較例１〜８〉 下記の配合の材料を混合して溶融混練後、粉砕分級し
て平均粒子径が11μｍの負帯電性のトナーを得た。<Examples 1 to 4 and Comparative Examples 1 to 8> Materials having the following formulations were mixed, melt-kneaded, and then pulverized and classified to obtain negatively chargeable toner having an average particle diameter of 11 μm.
次に第１表に示すような各疎水性シリカをヘンシェル
ミキサーを使用して上記トナーと混合し、各疎水性シリ
カをトナー粒子表面に付着せしめた。この各トナー3.5
重量部と各キャリア100重量部とを混合して本発明の電
子写真用現像剤及び比較用の現像剤を作製した。 Next, each hydrophobic silica as shown in Table 1 was mixed with the above toner using a Henschel mixer, and each hydrophobic silica was made to adhere to the toner particle surface. This each toner 3.5
Parts by weight and 100 parts by weight of each carrier were mixed to prepare the electrophotographic developer of the present invention and a comparative developer.
なお第１表に記した疎水性シリカの明細は第２表に示
すとおりである。The specifications of the hydrophobic silica shown in Table 1 are as shown in Table 2.
上記実施例１〜４にもとづく本発明の現像剤および比
較例１〜８にもとづく比較用の現像剤を電子複写機にて
15000枚まで常温常湿環境条件（20℃/65％RH）、低温低
湿環境条件（10℃/15％RH）、高温高湿環境条件（30℃/
85％RH）において多数枚複写を行い、画像濃度、非画像
部の地カブリ及び複写後の現像器周辺のトナー飛散につ
いて評価を行った。その結果を第３表に示す。なお、画
像濃度と地カブリはマクベス反射濃度計により測定し、
トナー飛散は目視により評価した。 The developer of the present invention based on Examples 1 to 4 and the comparative developer based on Comparative Examples 1 to 8 were electrophotographically machined.
Up to 15000 sheets Normal temperature and normal humidity environment conditions (20 ℃ / 65% RH), Low temperature and low humidity environment conditions (10 ℃ / 15% RH), High temperature and high humidity environment conditions (30 ℃ /
A large number of sheets were copied at 85% RH), and the image density, the background fog in the non-image area, and the toner scattering around the developing device after copying were evaluated. The results are shown in Table 3. The image density and background fog were measured with a Macbeth reflection densitometer,
Toner scattering was visually evaluated.
上記第３表から明らかなように本発明の電子写真用現
像剤は常温常湿、低温低湿、高温高湿の各環境条件にお
いても安定した画像濃度が得られ、地カブリも少なく、
トナー飛散も少ないことが確認された。 As is apparent from Table 3 above, the electrophotographic developer of the present invention can provide stable image density even under the environmental conditions of normal temperature and normal humidity, low temperature and low humidity, and high temperature and high humidity, and has little background fog.
It was also confirmed that toner scattering was small.
以上説明したように、本発明は特定の疎水性シリカを
使用し、かつキャリアとの組合せにおいて特定の飽和帯
電量となるようトナーに付着させることにより周囲の環
境により画像濃度が変化することなくトナー飛散、地カ
ブリが少なく、さらに多数枚の連続複写をおこなっても
優れた耐久性を示す電子写真用現像剤を提供することが
できる。As described above, according to the present invention, a specific hydrophobic silica is used, and when the toner is attached to the toner so as to have a specific saturated charge amount in combination with the carrier, the toner can be formed without changing the image density due to the surrounding environment. It is possible to provide an electrophotographic developer that has less scattering and background fog and exhibits excellent durability even when a large number of sheets are continuously copied.
Claims (4)
着してなる疎水化度が50％以上であり且つBET比表面積
が180m2/g以下の疎水性シリカと、キャリアからなる電
子写真用現像剤であって、前記キャリアに対する疎水性
シリカの飽和帯電量が−300〜＋200μc/gであることを
特徴とする電子写真用現像剤。1. An electron comprising a negatively chargeable toner, hydrophobic silica attached to the negatively chargeable toner and having a hydrophobicity of 50% or more and a BET specific surface area of 180 m 2 / g or less, and an electron. An electrophotographic developer, characterized in that the saturated charge amount of the hydrophobic silica with respect to the carrier is -300 to +200 µc / g.
の付着量が0.05〜１重量％であることを特徴とする請求
項１記載の電子写真用現像剤。2. The developer for electrophotography according to claim 1, wherein the amount of the hydrophobic silica attached to the negatively chargeable toner is 0.05 to 1% by weight.
着してなる疎水化度が50％以上であり且つBET比表面積
が180m2/g以下の疎水性シリカＡおよび疎水化度が50％
以上の疎水性シリカＢの混合物と、キャリアからなる現
像剤であって、 （Ａ）前記キャリアに対する疎水性シリカＡの飽和帯電
量が−300〜＋200μc/gであり、 （Ｂ）前記キャリアに対する疎水性シリカＢの飽和帯電
量が−300μc/gより負極性側に高い関係を有し、 （Ｃ）疎水性シリカＡに対する疎水性シリカＢの配合比
率が50重量％以下であること、を特徴とする電子写真用
現像剤。3. A negatively chargeable toner, and a hydrophobic silica A adhering to the negatively chargeable toner having a hydrophobicity of 50% or more and a BET specific surface area of 180 m 2 / g or less, and a hydrophobicity. 50%
A developer comprising a mixture of the above hydrophobic silica B and a carrier, wherein (A) the saturated charge amount of the hydrophobic silica A with respect to the carrier is −300 to +200 μc / g, and (B) the hydrophobic charge with respect to the carrier. The saturated charge amount of the hydrophobic silica B is higher than that of −300 μc / g on the negative side, and (C) the blending ratio of the hydrophobic silica B to the hydrophobic silica A is 50% by weight or less. A developer for electrophotography.
Ａおよび疎水性シリカＢの混合物の付着量が0.05〜１重
量％であることを特徴とする請求項３記載の電子写真用
現像剤。4. The electrophotographic developer according to claim 3, wherein the amount of the mixture of the hydrophobic silica A and the hydrophobic silica B attached to the negatively chargeable toner is 0.05 to 1% by weight.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1078013A JPH0812448B2 (en) | 1989-03-31 | 1989-03-31 | Electrophotographic developer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1078013A JPH0812448B2 (en) | 1989-03-31 | 1989-03-31 | Electrophotographic developer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02259658A JPH02259658A (en) | 1990-10-22 |
| JPH0812448B2 true JPH0812448B2 (en) | 1996-02-07 |
Family
ID=13649908
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1078013A Expired - Fee Related JPH0812448B2 (en) | 1989-03-31 | 1989-03-31 | Electrophotographic developer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0812448B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2633130B2 (en) * | 1991-03-08 | 1997-07-23 | キヤノン株式会社 | Magnetic toner, image forming method, surface-modified silica fine powder and method for producing the same |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58185405A (en) * | 1982-04-26 | 1983-10-29 | Nippon Aerojiru Kk | Fine powder of surface-modified metal oxide |
| JPH073601B2 (en) * | 1985-08-31 | 1995-01-18 | 京セラ株式会社 | Negatively charged developer |
| JPS62227159A (en) * | 1986-03-28 | 1987-10-06 | Kyocera Corp | Negatively electrifiable developer |
| JPH066183B2 (en) * | 1987-02-19 | 1994-01-26 | 日本電動特許株式会社 | Slot machine |
-
1989
- 1989-03-31 JP JP1078013A patent/JPH0812448B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02259658A (en) | 1990-10-22 |
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