JPH0728271A - Electrostatic charge image developer and developing method - Google Patents
Electrostatic charge image developer and developing methodInfo
- Publication number
- JPH0728271A JPH0728271A JP5153646A JP15364693A JPH0728271A JP H0728271 A JPH0728271 A JP H0728271A JP 5153646 A JP5153646 A JP 5153646A JP 15364693 A JP15364693 A JP 15364693A JP H0728271 A JPH0728271 A JP H0728271A
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- Prior art keywords
- magnetic
- toner
- magnetic toner
- developer
- resin
- 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.)
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- Dry Development In Electrophotography (AREA)
- Developing Agents For Electrophotography (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、静電荷像の現像剤及び
現像方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer and method for developing an electrostatic image.
【０００２】[0002]
【従来の技術】従来、磁性、非磁性両トナーを用いる現
像法には、いくつかの公知技術がある。その中で代表的
なものは特開昭54-24632号公報に記載されており、両ト
ナーを構成する樹脂の摩擦帯電特性が等しい磁性トナー
と非磁性トナーを混合して用い、露出した磁性体と非磁
性トナーとの摩擦帯電によって、非磁性トナーが磁性体
露出部に付着した二次粒子を形成し、良好な現像画像
や、定着性の向上を得ることができると記されている。2. Description of the Related Art Conventionally, there are some known techniques for developing using both magnetic and non-magnetic toner. A typical one of them is disclosed in JP-A-54-24632, in which a magnetic toner and a non-magnetic toner in which resins constituting both toners have the same triboelectrification characteristics are mixed and used, and an exposed magnetic material is used. It is described that the non-magnetic toner can form secondary particles adhered to the exposed portion of the magnetic material by frictional charging with the non-magnetic toner, and a good developed image and improved fixability can be obtained.
【０００３】しかし、上記の従来技術では、磁性、非磁
性両トナーの摩擦帯電を利用するため、逆極性のトナー
が発生しやすく、カブリの原因となりやすい。However, in the above-mentioned prior art, since triboelectrification of both magnetic and non-magnetic toners is utilized, toners of opposite polarity are likely to be generated and fog is likely to occur.
【０００４】[0004]
【発明が解決しようとする課題】本発明の課題は、上記
のごとき摩擦帯電作用を利用せずに現像器内で磁性トナ
ーの帯電性を高め、カブリのない現像性の良好な現像剤
を与えることにある。SUMMARY OF THE INVENTION An object of the present invention is to enhance the chargeability of a magnetic toner in a developing device without utilizing the frictional charging effect as described above, and to provide a developer with good fog-free developability. Especially.
【０００５】すなわち、磁性、非磁性両トナーの摩擦帯
電を利用せずに現像器内で磁性トナーの帯電性を高める
ことにより、カブリのない、高画像濃度を達成すること
にある。That is, it is to achieve a high image density without fog by increasing the chargeability of the magnetic toner in the developing device without utilizing the triboelectric charging of both magnetic and non-magnetic toner.
【０００６】[0006]
【課題を解決するための手段】本発明の課題は下記要件
を満たすことにより達成される。The objects of the present invention are achieved by satisfying the following requirements.
【０００７】少なくとも樹脂と磁性体とを含有する磁性
トナー（Ａ）と少なくとも樹脂と着色剤とを含有する非
磁性トナー（Ｂ）とからなる現像剤において、該非磁性
トナー（Ｂ）の現像剤中の含有率が0.2〜5.0重量％であ
り、体積平均粒径〔各々Ｄａ及びＤｂ(μm)〕との間に
下記の関係が存在することを特徴とする現像剤。A developer comprising a magnetic toner (A) containing at least a resin and a magnetic material and a non-magnetic toner (B) containing at least a resin and a colorant, in the developer of the non-magnetic toner (B). Is 0.2 to 5.0% by weight, and the following relationship exists with the volume average particle size [respectively Da and Db (μm)].
【０００８】0.8＜Ｄｂ／Ｄａ＜ 1.2 ここにおいて磁性トナー（Ａ）と非磁性トナー（Ｂ）の
鉄粉に対する帯電極性が同一（負極性）であり、（Ａ）
の帯電量をＱａμC／cm3，（Ｂ）の帯電量をＱｂμC／c
m3とする時、1.0＜Ｑａ／Ｑｂ＜10.0であり、かつ−50
＜Ｑａ＜−10であることが望ましい。0.8 <Db / Da <1.2 Here, the magnetic toner (A) and the non-magnetic toner (B) have the same charge polarity with respect to the iron powder (negative polarity), and (A)
Of the charge amount of QaμC / cm 3 , and the charge amount of (B) is QbμC / c
When the m 3, a 1.0 <Qa / Qb <10.0, and -50
It is desirable that <Qa <-10.
【０００９】（Ａ）と（Ｂ）の混合割合は、（Ａ）100
重量部に対して（Ｂ）0.2〜5.0重量部であり、好ましく
は1.0〜4.0重量部である。粒径は、両トナーともほぼ同
体積平均粒径であり、５〜20μmを有するものが用いら
れる。The mixing ratio of (A) and (B) is (A) 100.
The content of (B) is 0.2 to 5.0 parts by weight, preferably 1.0 to 4.0 parts by weight, based on parts by weight. The particle diameters of both toners are almost the same volume average particle diameter, and those having 5 to 20 μm are used.
【００１０】磁性トナーは現像スリーブ上に保持される
が、非磁性トナーは保持されずに現像剤中を自由に移動
して、スリーブ上に保持された磁性トナー層を撹拌又は
撹乱する作用を及ぼし、磁性トナー同志又は磁性トナー
と現像スリーブとの接触確率を高め、従って帯電性を高
める方向に働く。そして非磁性トナーは磁性トナー間に
はさまれ、保持されたまま現像・転写される。The magnetic toner is held on the developing sleeve, but the non-magnetic toner is not held and freely moves in the developer to exert an action of stirring or disturbing the magnetic toner layer held on the sleeve. , The contact probability between the magnetic toner or the magnetic toner and the developing sleeve is increased, and thus the charging property is increased. The non-magnetic toner is sandwiched between the magnetic toners and is developed and transferred while being held.
【００１１】[0011]
【作用】本発明に用いる樹脂は、荷電性、転写性、加熱
或は圧力定着性、クリーニング性、保存安定性、耐久性
などを考慮して選択される。具体例としては、例えば、
ポリスチレン、スチレン-無水マレイン酸共重合体、ス
チレン-アクリル系共重合体、スチレン-ブタジエン共重
合体などのスチレン及びその置換体の重合体または共重
合体、ポリ酢酸ビニル樹脂、ポリエステル樹脂、ポリア
クリル樹脂、ポリエポキシ樹脂、ポリアミド樹脂などが
使用される。The resin used in the present invention is selected in consideration of chargeability, transferability, heat or pressure fixing property, cleaning property, storage stability, durability and the like. As a specific example, for example,
Polymers or copolymers of styrene and its substitutes such as polystyrene, styrene-maleic anhydride copolymer, styrene-acrylic copolymer, styrene-butadiene copolymer, polyvinyl acetate resin, polyester resin, polyacrylic Resin, polyepoxy resin, polyamide resin, etc. are used.
【００１２】本発明を構成する磁性体としては、磁場に
よってその方向に強く磁化する物質、例えば鉄、フェラ
イト、マグネタイトをはじめとするニッケル、コバルト
等の強磁性を示す金属あるいはこれらの金属を含む合金
または化合物等を挙げることができる。The magnetic substance constituting the present invention is a substance which is strongly magnetized in that direction by a magnetic field, for example, iron, ferrite, magnetite or other metals showing ferromagnetism such as nickel and cobalt, or alloys containing these metals. Alternatively, a compound or the like can be given.
【００１３】磁性体の平均粒径は、0.50μm以下が好ま
しく、さらには0.10μmから0.30μmの範囲が好ましい。
ここで磁性体の平均粒径とは、透過型電子顕微鏡により
得られた５千倍の写真を４倍に拡大して、２万倍の写真
とした後、ランダムに250個の磁性体を選び、その径を
実測した個数平均粒径をいう。The average particle size of the magnetic material is preferably 0.50 μm or less, more preferably 0.10 μm to 0.30 μm.
Here, the average particle size of the magnetic material means that a 5,000 times photograph obtained by a transmission electron microscope is magnified 4 times to make a 20,000 times photograph, and then 250 magnetic materials are randomly selected. , The number average particle diameter of the measured diameter.
【００１４】磁性体の含有量は、現像方式によっても異
なるが、トナー中に20〜60重量％添加することができ、
好ましくは25〜50重量％である。磁性体は「球形」のも
のが好ましく、「球形」とは透過電子顕微鏡によって観
察した際に、その形状が曲面より構成されてなり短径／
長径比が0.9以上であるものを指す。非磁性トナーの着
色剤として磁性体は使用しない。Although the content of the magnetic substance varies depending on the developing method, it can be added in an amount of 20 to 60% by weight in the toner.
It is preferably 25 to 50% by weight. The magnetic substance is preferably “spherical”, and the “spherical” means that the shape is composed of a curved surface when observed by a transmission electron microscope.
It means that the ratio of major axis is 0.9 or more. No magnetic material is used as a coloring agent for non-magnetic toner.
【００１５】又本発明の離型剤としては、例えば低分子
量ポリプロピレン、低分子量ポリエチレン等のポリオレ
フィン、脂肪酸エステル、高級脂肪酸、高級アルコー
ル、パラフィンワックス、アミド系ワックス、多価アル
コールエステル等を用いることができる。離型剤の含有
割合は、樹脂と磁性体粒子の合計100重量部に対して好
ましくは１〜10重量部である。As the release agent of the present invention, for example, polyolefin such as low molecular weight polypropylene and low molecular weight polyethylene, fatty acid ester, higher fatty acid, higher alcohol, paraffin wax, amide wax, polyhydric alcohol ester and the like can be used. it can. The content ratio of the release agent is preferably 1 to 10 parts by weight based on 100 parts by weight of the total of the resin and the magnetic particles.
【００１６】本発明のトナーを得るに際して、前記樹
脂、磁性体及び離型剤のほかに必要に応じて用いられる
添加剤としては、例えば荷電制御剤等がある。In addition to the resin, magnetic material, and release agent, additives that are optionally used in obtaining the toner of the present invention include, for example, a charge control agent.
【００１７】トナーの帯電量は、添加する荷電制御剤の
種類や添加量で調整することが可能であり、ニグロシン
系、アゾ系、第４級アンモニウム塩系、チオ尿素系等の
顔料又は染料を用いることができる。The charge amount of the toner can be adjusted by the kind and addition amount of the charge control agent to be added, and a pigment or dye such as a nigrosine type, an azo type, a quaternary ammonium salt type, or a thiourea type is used. Can be used.
【００１８】本発明の静電荷像現像用トナーは、粉砕分
級後のトナーに対して無機微粉末、クリーニング性向上
助剤の外部添加剤が添加混合されたものであってもよ
い。The toner for developing an electrostatic charge image of the present invention may be a mixture of the toner after pulverization and classification with an inorganic fine powder and an external additive such as a cleaning property improving aid.
【００１９】無機微粉末としては、特に金属もしくは非
金属の酸化物の微粒子を好ましく用いることができ、具
体的には、酸化珪素、酸化チタン、酸化アルミニウム、
酸化セリウム、酸化クロム、チタン酸ストロンチウム等
を用いることができる。これらは組合せて用いてもよ
い。またカップリング剤等により疎水化したものが好ま
しく使用できる。As the inorganic fine powder, particularly fine particles of metal or non-metal oxide can be preferably used, and specifically, silicon oxide, titanium oxide, aluminum oxide,
Cerium oxide, chromium oxide, strontium titanate, etc. can be used. These may be used in combination. Further, those hydrophobized with a coupling agent or the like can be preferably used.
【００２０】帯電量の測定方法は、鉄粉キャリア「ＤＳ
Ｐ−138」（パウダーテック社製）100重量部と現像剤３
重量部とを混合し、１分間振盪した後ブローオフ法によ
り測定した。測定環境は温度20℃、相対湿度50％の条件
で行ない、振盪は「ＹＳ−ＬＤ型」（ヤヨイ社製）振角
45°で行なった。The method of measuring the charge amount is the iron powder carrier "DS
P-138 "(Powder Tech) 100 parts by weight and developer 3
It was measured by the blow-off method after mixing with 1 part by weight and shaking for 1 minute. The measurement environment is 20 ° C and 50% relative humidity, and the shaking is “YS-LD type” (Yayoi Co., Ltd.).
Performed at 45 °.
【００２１】帯電量の単位（μC／cm3）はブローオフ法
で求めた帯電量（μC／ｇ）にトナーの真比重（ｇ／c
m3）を掛けた値として求めた。The unit of the charge amount (μC / cm 3 ) is based on the charge amount (μC / g) obtained by the blow-off method and the true specific gravity (g / c) of the toner.
m 3 ).
【００２２】真比重は、AUTO TRUE DENSER「MAT−500
0」（セイシン企業社製）で測定し、粒径は、コールタ
ーカウンターＴＡ−II（コールター・エレクトロニクス
社製）で測定した体積平均粒径を示す。The true specific gravity is AUTO TRUE DENSER "MAT-500".
0 "(manufactured by Seishin Enterprise Co., Ltd.), and the particle size is the volume average particle size measured by Coulter Counter TA-II (manufactured by Coulter Electronics Co.).
【００２３】磁性トナーと非磁性トナーの帯電量比率、
体積平均粒径比率及び非磁性トナーの含有率を制御した
現像剤を適用することにより、画像濃度の良好なカブリ
のない画像を得ることができる。Charge amount ratio of magnetic toner and non-magnetic toner,
By applying a developer in which the volume average particle diameter ratio and the content of the non-magnetic toner are controlled, it is possible to obtain a fog-free image having a good image density.
【００２４】Ｑａ／Ｑｂ値が10.0以上又は、1.0以下の
場合には、逆極性トナーによるカブリが発生する。When the Qa / Qb value is 10.0 or more or 1.0 or less, fog occurs due to the opposite polarity toner.
【００２５】Ｄｂ／Ｄａ値が1.2以上、非磁性トナー含
有率が5.1重量％以上になると非磁性トナーの磁性トナ
ー間での保持ができにくくなり、カブリが発生する。When the Db / Da value is 1.2 or more and the content ratio of the non-magnetic toner is 5.1% by weight or more, it becomes difficult to hold the non-magnetic toner between the magnetic toners and fog occurs.
【００２６】Ｄｂ／Ｄａ値が0.8以下、非磁性トナー含
有率が0.1重量％以下では磁性トナー層の撹拌作用が不
十分となり、画像濃度を高めることができなくなる。When the Db / Da value is 0.8 or less and the content ratio of the non-magnetic toner is 0.1% by weight or less, the stirring effect of the magnetic toner layer becomes insufficient and the image density cannot be increased.
【００２７】評価に使用した機械は、現像器としてマグ
ロール固定スリーブのみ回転するもので、現像剤層規制
方式としては磁気力によって押圧されるトナー搬送規制
部材を使用しているものである。スリーブはステンレス
で構成され、ブラスト処理されており、直径は30mmで、
トナー搬送規制部材の直径は５mmである。さらに、搬送
されたトナー層の厚みは約150μmである。また、感光体
としては有機感光体を使用し、感光体と現像剤層との間
隙は300μmであり、現像バイアスとしてＤＣ＝−500Ｖ
を印加し、ＡＣバイアスとして周波数＝２KHZ・ＶP-P＝
1000Ｖを印加している。The machine used for the evaluation is one in which only the mag roll fixing sleeve is rotated as a developing device, and the toner layer regulating member pressed by magnetic force is used as the developer layer regulating system. The sleeve is made of stainless steel, is blasted, has a diameter of 30 mm,
The diameter of the toner transport regulation member is 5 mm. Further, the thickness of the transported toner layer is about 150 μm. An organic photoconductor is used as the photoconductor, the gap between the photoconductor and the developer layer is 300 μm, and the developing bias is DC = −500V.
Is applied, and the frequency is 2KH Z · V PP = as AC bias.
1000V is applied.
【００２８】[0028]
【実施例】以下、実施例を挙げて本発明を詳細に説明す
るが、本発明の態様はこれに限定されない。The present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.
【００２９】 〈磁性トナー（Ａ）の作製〉 スチレン-アクリル樹脂 100重量部 磁性体（マグネタイト：球形化度＝0.95，一次粒径＝0.21μm） 56重量部 荷電制御剤（構造式下記） 0.5重量部 低分子量ポリプロピレン 3重量部 以上を混合し、混練・粉砕・分級して体積平均粒径が1
1.0μmの磁性トナーを得た（実施例−１，４，５，６，
７）（比較例−３，４，５，６，７）。<Production of Magnetic Toner (A)> 100 parts by weight of styrene-acrylic resin Magnetic material (magnetite: sphericity = 0.95, primary particle size = 0.21 μm) 56 parts by weight Charge control agent (following structural formula) 0.5 parts by weight 3 parts by weight of low-molecular-weight polypropylene
Magnetic toner of 1.0 μm was obtained (Examples 1, 4, 5, 6,
7) (Comparative Examples-3, 4, 5, 6, 7).
【００３０】さらに荷電制御剤の添加量を変化させて、
帯電性の異なる磁性トナーを作製した（実施例−２，
３）（比較例−１，２）。Further, by changing the addition amount of the charge control agent,
Magnetic toners having different charging properties were prepared (Example-2,
3) (Comparative Examples-1 and 2).
【００３１】これらは表１に他の要件、結果と合せて記
載してある。These are shown in Table 1 together with other requirements and results.
【００３２】[0032]
【化１】 [Chemical 1]
【００３３】 〈非磁性トナー（Ｂ）の作製〉 スチレン-アクリル樹脂 100重量部 カーボンブラック 10重量部 低分子量ポリプロピレン 5重量部 ワックス 3重量部 以上を混合し、混練・粉砕・分級して体積平均粒径が1
1.0μmの非磁性トナーを得た（実施例−１，２，３，
６，７）（比較例−１，２，５，６）。又粉砕・分級条
件を調整して、異なる体積平均粒径を有する非磁性トナ
ーを得た（実施例−４，５）（比較例−３，４）。<Preparation of Non-Magnetic Toner (B)> Styrene-acrylic resin 100 parts by weight Carbon black 10 parts by weight Low molecular weight polypropylene 5 parts by weight Wax 3 parts by weight Diameter 1
1.0 μm of non-magnetic toner was obtained (Examples 1, 2, 3,
6, 7) (Comparative Examples-1, 2, 5, 6). Further, the pulverization / classification conditions were adjusted to obtain non-magnetic toners having different volume average particle diameters (Examples 4,5) (Comparative Examples -3, 4).
【００３４】上記のごとき磁性、非磁性両トナーを表１
の様な非磁性トナー含有率で混合し、混合物に対して疎
水性シリカ（Ｒ−812：日本アエロジル社製）を0.4％添
加して本発明の現像剤を得た。Both magnetic and non-magnetic toners as described above are shown in Table 1.
The above non-magnetic toner content was mixed, and 0.4% of hydrophobic silica (R-812: manufactured by Nippon Aerosil Co., Ltd.) was added to the mixture to obtain the developer of the present invention.
【００３５】〈評価〉評価は、コニカ社製レーザープリ
ンターＬＰ−3015を改造してＡ４縦送りでの印字速度を
20枚／分とし、６極の固定磁石を内蔵した直径25mmの磁
性ステンレス製の現像スリーブを有し、現像領域間隙：
Ｄsd＝0.3mmとし、現像領域における現像器表面におけ
るトナー層を0.15mmとした非接触方式、感光体は積層型
有機感光体を使用、現像バイアスとしてＤＣ＝−500Ｖ
を印加、ＡＣバイアス周波数＝２KHZ・ＶP-P＝1000Ｖを
印加した現像方式の機械を使用した。結果は、画像濃度
及びカブリを評価した。<Evaluation> The evaluation was carried out by modifying the laser printer LP-3015 manufactured by Konica Corporation to determine the printing speed in A4 longitudinal feeding.
20 sheets / min, with a developing sleeve made of magnetic stainless steel with a diameter of 25 mm that has a built-in 6-pole fixed magnet.
Dsd = 0.3 mm, non-contact type with toner layer on the surface of the developing device in the developing area of 0.15 mm, the photoconductor uses a laminated organic photoconductor, and the developing bias is DC = -500V
Was applied and an AC bias frequency = 2 KH Z · V PP = 1000 V was applied to the development type machine. The results evaluated image density and fog.
【００３６】画像濃度は、５％画素のパターンをＡ４
1000枚印字後のベタ黒画像を12点測定し、平均した絶対
反射濃度で示す。又カブリはＡ４ 1000枚印字後のベタ
白画像を12点測定し、紙自体の濃度を「0.000」とした
平均相対反射濃度で示した。濃度測定は、マクベス社製
「ＲＤ−918」を使用した。The image density is A4 for a pattern of 5% pixels.
The solid black image after printing 1000 sheets is measured at 12 points, and the average absolute reflection density is shown. Fogging was measured by measuring 12 points of solid white images after printing 1000 sheets of A4, and showing the average relative reflection density with the density of the paper itself being "0.000". For the concentration measurement, "RD-918" manufactured by Macbeth was used.
【００３７】[0037]
【表１】 [Table 1]
【００３８】表１の結果に示す様に、本発明によってカ
ブリのない、画像濃度の良好なトナーを得ることができ
る。As shown in the results of Table 1, according to the present invention, a toner having a good image density without fog can be obtained.
【００３９】[0039]
【発明の効果】本発明によれば、磁性トナー中に少量の
非磁性トナーを添加することにより、現像器内で磁性ト
ナーの帯電性を向上することができ、カブリのない、画
像濃度の良好な現像剤を得ることができる。According to the present invention, by adding a small amount of non-magnetic toner to the magnetic toner, the chargeability of the magnetic toner in the developing device can be improved, and there is no fog and the image density is good. It is possible to obtain a different developer.
Claims (2)
性トナー（Ａ）と少なくとも樹脂と着色剤とを含有する
非磁性トナー（Ｂ）とからなる現像剤において、該非磁
性トナー（Ｂ）の現像剤中の含有率が0.2〜5.0重量％で
あり、体積平均粒径〔各々Ｄａ及びＤｂ(μm)〕と帯電
量〔各々Ｑａ及びＱｂ(μC／cm3)〕との間に下記の関係
が存在することを特徴とする現像剤。 1.0＜Ｑａ／Ｑｂ＜10.0 0.8＜Ｄｂ／Ｄａ＜ 1.21. A developer comprising a magnetic toner (A) containing at least a resin and a magnetic substance and a non-magnetic toner (B) containing at least a resin and a colorant, and developing the non-magnetic toner (B). The content in the agent is 0.2 to 5.0% by weight, and the following relationship is established between the volume average particle size [respectively Da and Db (μm)] and the charge amount [respectively Qa and Qb (μC / cm 3 )]. A developer characterized by being present. 1.0 <Qa / Qb <10.0 0.8 <Db / Da <1.2
イアス下で非接触現像を行うことを特徴とする現像方
法。2. A developing method comprising performing non-contact development under an alternating bias using the developer according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15364693A JP3282050B2 (en) | 1993-06-24 | 1993-06-24 | Electrostatic image developer and developing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15364693A JP3282050B2 (en) | 1993-06-24 | 1993-06-24 | Electrostatic image developer and developing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0728271A true JPH0728271A (en) | 1995-01-31 |
| JP3282050B2 JP3282050B2 (en) | 2002-05-13 |
Family
ID=15567089
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15364693A Expired - Fee Related JP3282050B2 (en) | 1993-06-24 | 1993-06-24 | Electrostatic image developer and developing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3282050B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7212752B2 (en) | 2004-08-05 | 2007-05-01 | Konica Minolta Business Technologies, Inc. | Image forming apparatus and a developing apparatus having a unit for determining a mixture ratio of two types of magnetic toner based on magnetic permeability and amount |
| US7248805B2 (en) | 2004-08-05 | 2007-07-24 | Konica Minolta Business Technologies, Inc. | Image forming apparatus and developing unit |
-
1993
- 1993-06-24 JP JP15364693A patent/JP3282050B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7212752B2 (en) | 2004-08-05 | 2007-05-01 | Konica Minolta Business Technologies, Inc. | Image forming apparatus and a developing apparatus having a unit for determining a mixture ratio of two types of magnetic toner based on magnetic permeability and amount |
| US7248805B2 (en) | 2004-08-05 | 2007-07-24 | Konica Minolta Business Technologies, Inc. | Image forming apparatus and developing unit |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3282050B2 (en) | 2002-05-13 |
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