JP2004117971A - Development method and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce problems such as fogging, splashing and diffused transfer due to a heterogeneous toner, to enhance transfer efficiency, to dispense with a cleaner and to diminish waste toner. <P>SOLUTION: In the developing method in which a single component nonmagnetic toner carried on a developer carrier is charged by press-regulating with a regulating member, and the charge is imparted to an electrostatic latent image formed on an image carrier to convert the latent image to a visible image as a toner image, in the case where the particle size and charge amount of each toner particle of the single component nonmagnetic toner after press regulation by the regulating member are measured by a laser Doppler method in an oscillating field in an acoustic relaxation cell, development is performed after control which satisfies the relation of a>b between a particle size a [μm] of a particle size segment in which the number of particles is largest in the particle size distribution of the single component nonmagnetic toner and a particle size b [μm] of a particle size segment in which the number of particles is largest in a particle size distribution for each charge amount segment. <P>COPYRIGHT: (C)2004,JPO

Description

【００８４】
次に、同様の現像装置を用い、非接触にて、直流成分としてＶｄｃ＝３００Ｖに交流成分としてＶｐｐ１．３Ｋｖを重畳して感光体にトナー像形成を行った結果、現像効率９０％以上で、カブリトナ−及び飛散がほとんど発生しない画像形成が可能であった。さらに、図１の画像形成装置を用いて画像形成を行ったところ、感光体から中間転写媒体への１次転写効率が９９．９％以上であり、廃トナーの削減とクリーナレス画像形成装置による画像形成（クリーナレスプロセス）を実現することができた。
【００８５】
実施例２
実施例１と同じトナー母粒子を用い、外添剤として、１次粒径４０ｎｍのヘキサメチルジシラザン（以下、「ＨＭＤＳ」と記す）処理したシリカ（日本アエロジル社製；ＲＸ５０）０．５重量％、と１次粒径７ｎｍのＨＭＤＳ処理シリカ（日本アエロジル社製；ＲＸ３００）０．５重量％を用いて実施例１と同様の操作でトナーを作製した。
【００８６】
このトナーを用いて、実施例１と同様に負帯電させた後、粒径分布と帯電量分布を測定した。その結果を表２に示す。表２より、トナーの粒径分布における最も個数の多い粒径区分の粒径ａ［μｍ］と、帯電量区分毎の粒径分布における最も個数の多い粒径区分の粒径ｂ［μｍ］との関係は、ａ＝６．２５（６８０個の区分）、ｂ＝５．２５（１９７個の区分）となり、ａ＞ｂの条件を満たすものであった。
【００８７】
【表２】

【００８８】
比較例１
トナー母粒子の樹脂として実施例１とは異なる樹脂Ｘを用いた以外は実施例１と同様にしてトナーを作成した。このトナーについて、実施例１と同様に非接触方式の現像装置において負帯電させた。この帯電トナー粒子約３０００個について、粒径と帯電量とを測定した。その結果を表３に示す。表３より、トナーの粒径分布における最も個数の多い粒径区分の粒径ａ［μｍ］と、帯電量区分毎の粒径分布における最も個数の多い粒径区分の粒径ｂ［μｍ］との関係は、ａ＝４．７５（１０７６個の区分）、ｂ＝４．７５（３７２個の区分）となり、ａ＞ｂの条件を満たしていなかった。
【００８９】
【表３】

【００９０】
また、このトナーを用いて実施例１と同様に現像を行ったところ、バイアス電圧を５００Ｖに上げてもほとんど現像することが出来なかった。
【００９１】
比較例２
トナー母粒子の樹脂として実施例１とは異なる樹脂Ｙを用いた以外は実施例１と同様にしてトナーを作成した。このトナーについて、実施例１と同様に非接触方式の現像装置において負帯電させた。この帯電トナー粒子約３０００個について、粒径と帯電量とを測定した。その結果を表４に示す。表４より、トナーの粒径分布における最も個数の多い粒径区分の粒径ａ［μｍ］と、帯電量区分毎の粒径分布における最も個数の多い粒径区分の粒径ｂ［μｍ］との関係は、ａ＝４．７５（１２４５個の区分）、ｂ＝４．７５（４０９個の区分）となり、ａ＞ｂの条件を満たしていなかった。
【００９２】
【表４】

【００９３】
また、このトナーを用いて実施例１と同様に現像を行ったところ、現像効率は８０％であったが、カブリが発生し、良好な画像を形成することができなかった。また、感光体への１次転写効率は９９．９％と良好であったが、色重ねを行ったとき、逆転写トナーが発生し、クリーナレスを実現することができなかった。
【００９４】
実施例３
個数平均粒径が５μｍのトナー母粒子を使用し、外添剤として小粒径シリカ（日本アエロジル社製；ＲＸ３００）０．１重量％のみを用いた以外は実施例１と同様にしてトナーを作成した。このトナーを実施例１と同様にして負帯電させ、帯電トナー粒子約３０００個について、粒径と帯電量とを測定した。その結果を表５に示す。表５より、トナーの粒径分布における最も個数の多い粒径区分の粒径ａ［μｍ］と、帯電量区分毎の粒径分布における最も個数の多い粒径区分の粒径ｂ［μｍ］との関係は、ａ＝４．７５（７４６個の区分）、ｂ＝３．７５（２２９個の区分）となり、ａ＞ｂであった。
【００９５】
【表５】

【００９６】
比較例３
トナー母粒子の樹脂として実施例１とは異なる樹脂Ｚを用いた以外は実施例１と同様にしてトナーを作成した。実施例１と同様に非接触方式の現像装置において負帯電させた。ただし、規制ブレード通過時の搬送量は０．６ｍｇ／ｃｍ^２とした。この帯電トナー粒子約３０００個について、粒径と帯電量とを測定した。その結果を表６に示す。表６より、トナーの粒径分布における最も個数の多い粒径区分の粒径ａ［μｍ］と、帯電量区分毎の粒径分布における最も個数の多い粒径区分の粒径ｂ［μｍ］との関係は、ａ＝５．２５（８０４個の区分）、ｂ＝５．２５（２１２個の区分）となり、ａ＞ｂの条件を満たしていなかった。
【００９７】
【表６】

【００９８】
また、このトナーを用いて実施例１と同様に現像を行ったところ、現像効率は４０％以下で、カブリや飛散が発生した。
【００９９】
以上、本発明を種々の実施形態に関して述べたが、本発明は上記実施形態に制約されるものではなく、特許請求の範囲に記載された発明の範囲内で、他の実施形態についても適用可能である。
【図面の簡単な説明】
【図１】本発明現像方法に使用可能な画像形成装置の例を示す図面。
【図２】本発明現像方法に使用可能な現像装置の例を示す図面。
【図３】本発明現像方法に使用可能な画像形成装置の別の例を示す図面。
【符号の説明】
１　画像形成装置、１１　画像形成ユニット、２１　画像形成ステーション、
２３　感光ドラム、２５　コロナ帯電手段、１００　現像装置、
１０１　トナー収容部、１０３　ハウジング、１０５　供給ローラ、
１０７　現像ローラ、１０９　規制ブレード、１１１　板バネ部材、
１１２　弾性部材、１１３　トナー、１１４　トナーの上面、
１１５　シール部材、１１９　アジテータ、１２３　撹拌フィン
１２５　トナー収容部の内周面と撹拌フィンとの間の領域
１２７　規制ブレードが現像ローラの周面に当接している箇所
１２９　トナー案内面、１３１　トナー案内空間部、
１３３　トナーガイド部材、
１３４　供給ローラから離れた側のトナーガイド部材の端部、
１３５　スクレーパ、１３７　平坦搬送部、１３９　トナーの一時貯留部、
１４１　湾曲部、１４３　当接部、１４７　シール側壁、
１４９　当接シート、１５３　シャッター部材、
１５５　トナー量監視センサ、１５７　コイルバネ、
１５９　ソレノイド弁、１６１　回動支点、１６３　回転軸[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a developing method and an image forming method, and more particularly, to a developing method and an image forming method that are performed in image formation of an electrostatic latent image developing system used for a printer, a copying machine, and the like.
[0002]
[Prior art]
It is known that the charge amount of the toner used in the image formation of the electrostatic latent image developing system has a great influence on the image formation. Specifically, in the electrophotographic process, the toner adheres to the photoconductor by the charging characteristics of each toner particle, and is transferred to the transfer body, thereby forming an image. Therefore, it is considered that many of the problems in the electrophotographic process, such as fogging, scattering, transfer dust, deterioration over time, and environmental deterioration, are caused by the Wrong toner whose charge amount cannot be controlled. For this reason, in the conventional process, how to make the charge of the toner uniform has been a major issue.
[0003]
For the image forming method of controlling the charging property of the toner, the specific electrical resistance value R of the developing toner to be used satisfies ^{R ≧ 1 × 10 13 Ω ·} cm, and the developer toner charge amount q _t is 0.5 _{[mC / kg] ≦ | q} t | ≦ 40 [mC / kg] cleanerless image forming method is set to have been proposed (see Patent Document 1). However, this image forming method merely specifies the charge amount of the developed toner in relation to the specific electric resistance value, and the relationship between the charge amount distribution and the particle size distribution in the toner as an aggregate of individual particles. No suggestion is made.
[0004]
Further, as another example of the developing method, the resistance value of the developer containing the magnetic carrier and the toner at the electric field strength of 500 V / cm is R ₅₀₀ [Ω · cm] and the resistance value at the electric field strength of 2500 V / cm is R ₂₅₀₀ [ Ω · cm], an index Y of the voltage dependency of the developer, which is obtained from the following formula, and a charge amount Q [femt. C] and the particle ratio D [μm], the number ratio X [%] of the uncharged toner in the entire toner, which falls within the region of Q / D <0.2, is defined as , Y> (3X / 400) +1 is proposed (see Patent Document 2). However, this toner is a two-component toner containing a magnetic carrier and a toner, and further only defines the number ratio of the uncharged toner that causes image bleeding in relation to the resistance value at a predetermined electric field strength. No consideration is given to the relationship between the charge amount distribution and the particle size distribution in the toner as an aggregate of individual particles.
[0005]
[Patent Document 1]
JP-A-5-2287 (page 3)
[Patent Document 2]
JP-A-8-129268 (pages 2 to 3)
[0006]
[Problems to be solved by the invention]
Conventionally, the charge amount of the toner is merely regarded as the sum of the charge amounts of the toner on the basis of its mass, and therefore, the charge amount of each toner cannot be controlled. As a result, there is still Wron toner whose charge amount cannot be fully controlled, which causes fogging and the like, reduces transfer efficiency, and impairs image quality. Further, the decrease in transfer efficiency increases waste toner remaining on the photoreceptor after transfer, and hinders omission and simplification (cleanerless) of a cleaner mechanism for cleaning the toner. As described above, in the developing methods proposed so far, there is a limit in responding to high image quality of image formation, downsizing of the apparatus, and the like.
[0007]
Accordingly, an object of the present invention is to reduce the problems of fogging, scattering, transfer dust and the like due to non-uniform toner, and at the same time, to increase the transfer efficiency, to make cleaner-less and to reduce waste toner, and to form an image. It is to provide a method.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention of the developing method according to the first aspect of the present invention is a method of controlling a one-component non-magnetic toner carried on a developer carrier to be negatively charged by regulating the pressure by a regulating member. In the developing method of applying a latent image formed on an image carrier to a visible image as a toner image, the one-component non-magnetic toner after being regulated by the regulating member is pressed in the acoustic relaxation cell. When the particle size and charge amount of individual toner particles are measured by a laser Doppler method in a vibration field, a particle size a [μm] of a particle size distribution having the largest number in the particle size distribution of the one-component non-magnetic toner; It is characterized in that development is performed by controlling the relationship with the particle size b [μm] of the particle size distribution having the largest number in the particle size distribution for each charge amount distribution so that a> b.
In a developing method in which a one-component non-magnetic toner is negatively charged while being regulated by a regulating member, it is important to grasp the charge amount distribution of a certain toner set in relation to the particle size distribution of the toner set. Then, as shown in Examples described later, when the relationship between the charge amount distribution and the particle size distribution is controlled so that a> b, the toner performance is in a good state, and fog, scattering, and transfer It became clear that problems such as dust, deterioration over time, and environmental deterioration can be solved. When focusing on the surface of one toner particle, the toner satisfying this condition is uniformly charged in an ideal state without uneven distribution of a reverse charge (for example, a positively charged portion on a negatively charged toner surface) in the surface charge distribution. It is thought that it is. Therefore, by performing the development under the conditions satisfying the above conditions, it becomes possible to reduce the Wron toner as much as possible.
[0009]
In the developing method according to a second aspect of the present invention, in the first aspect, a reverse polarity toner in the measured charge amount distribution of the one-component non-magnetic toner (for example, a positively charged toner in a negatively charged toner). Is controlled so that the ratio is less than 5%. According to this feature, in addition to the condition of a> b, by controlling the ratio of the opposite polarity toner to be less than 5%, the occurrence of fog is further suppressed, and the toner performance is further improved. The development can be performed in the state.
[0010]
In the developing method according to the third aspect of the present invention, in the second aspect, the number of toners in the largest charge amount section in the charge amount distribution for each particle diameter section may be 10% or more of the entire toner. It is characterized in that development is performed under control. According to this feature, by controlling the number of toners in the charge amount category having the largest number to be 10% or more of the entire toner, development can be performed in a state where toner performance is optimal.
[0011]
According to a fourth aspect of the present invention, there is provided an image forming method comprising: transferring a toner image on an image carrier, which is visualized by the developing method according to any one of the first to third aspects, to form an image; It is characterized by forming. According to this feature, it is possible to form an image in a state in which the Wron toner is minimized by the developing method according to any one of the first to third aspects, so that fog, scattering, transfer dust, and the like can be formed. The problem can be avoided, the transfer efficiency is increased, and the waste toner can be reduced.
[0012]
An image forming method according to a fifth aspect of the present invention is the image forming method according to the fourth aspect, wherein an image forming apparatus having no cleaner mechanism for cleaning waste toner remaining on the image carrier after transfer is used. And As described above, in the image forming method of the present invention, the Wron toner is suppressed as much as possible, and the transfer is performed with high efficiency. Therefore, the cleaning step for cleaning the waste toner remaining on the image carrier can be omitted. It is. Therefore, an image can be formed even in a cleaner-less image forming apparatus in which the cleaner mechanism is omitted, and downsizing and simplification of the image forming apparatus are realized.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
In the developing method of the present invention, the one-component non-magnetic toner carried on the developer carrier is charged by regulating the pressure by the regulating member, and then applied to the electrostatic latent image formed on the image carrier. In the process of being visualized as a toner image, for the one-component non-magnetic toner that has been pressed and regulated by the regulating member, the individual toner particle velocities are measured by a laser Doppler method in a vibration field in an acoustic relaxation cell, and the When the individual particle size and charge amount are calculated based on the measurement results, the particle size a [μm] of the largest number of particle size classes in the particle size distribution of the one-component non-magnetic toner, and the particle size for each charge amount class The development is performed by controlling the relationship with the particle size b [μm] of the largest number of particle size distributions in the distribution so that a> b.
[0014]
The toner used in the developing method of the present invention is a one-component non-magnetic toner, and a known toner can be used. More specifically, the types and amounts of binder resins, colorants, additives and the like used in the one-component non-magnetic toner, the shape and particle size of the base particles, and various known toners are described later. And a toner material can be appropriately selected and designed.
[0015]
The particle size and the amount of charge of the one-component non-magnetic toner are measured by a laser Doppler method in a vibration field in an acoustic relaxation cell. The laser Doppler method uses the phenomenon that when a laser beam is applied to a moving object, the frequency of the reflected light that returns is changed in proportion to the speed of the moving object (Doppler effect). It is a known method of measuring. In the present invention, the aerodynamic diameter of a particle (having the same sedimentation velocity as a particle) is measured by using the laser Doppler method to measure the velocity of the particle in an acoustic field or the phase delay angle of the particle motion with respect to the gas motion. The diameter of a unit density sphere) and the amount of charge are determined. The measurement of the particle size and the charge amount by the laser Doppler method can be performed using a commercially available measuring instrument. As an example of a preferred measuring instrument, there can be mentioned an ESPART Analyzer (registered trademark) model EST-3 (manufactured by Hosokawa Micron Corporation). In the measurement using the EASPART analyzer, a toner particle serving as a sample is dropped between two electrodes having opposite polarities. The charged toner particles move toward the electrode due to the electric field effect of the electrode. By acoustically vibrating the electrode, the particle is also attracted to the electrode while vibrating. At this time, the movement to the electrode and the vibration are simultaneously measured by the laser Doppler method to calculate the particle diameter and the charge amount.
[0016]
That is, the toner particles flowing from the entrance of the measuring machine receive air vibration by sound, and vibrate with a phase delay due to the inertia of the particles. Since the larger the particles, the larger the phase lag, the particle diameter can be measured from the phase lag. Further, the charge amount of the particles can be calculated from the moving speed to the electrode and the particle size.
[0017]
When measuring toner particles with this e-part analyzer, the results may fluctuate depending on the measurement conditions, operations, etc., so it is necessary to perform the measurement while fixing the conditions and operations as shown in the examples below. preferable.
[0018]
In the developing method of the present invention, the particle size a [μm] of the largest number of particle size distributions in the particle size distribution of the one-component non-magnetic toner measured by the above measurement method and the particle size distribution of the charge amount distribution in each particle size distribution The relationship with the particle size b [μm] of a large number of particle size classes is controlled so that a> b. When the charged toner satisfies the condition of a> b, it is assumed that the charged toner has a uniform charge state on the surface of each toner particle. Therefore, it is possible to perform control with higher accuracy than the conventional method in which the charge amount (collected as (total of charge amount / mass of toner set)) as a set of toner particles is controlled, and fog, scattering, Problems such as transfer dust can be solved.
[0019]
Here, the particle size class and the charge amount class are based on the particle size-charge amount class (see Table 1 and the like) divided by the particle size class for every 0.5 μm and the charge class for every 0.5 fC. .
[0020]
In addition to the condition of a> b, the ratio of the opposite polarity toner in the measured charge amount distribution of the one-component non-magnetic toner (that is, after being regulated by the regulating member) is set to be less than 5%. It is more preferable to control. By setting the ratio of the opposite polarity toner to less than 5%, waste toner can be suppressed as much as possible, and it becomes easy to realize cleanerless image forming apparatuses.
[0021]
Further, it is preferable to perform development while controlling the number of toners in the charge amount section having the largest number in the charge amount distribution for each particle diameter section to be 10% or more of the entire toner. Thereby, development can be performed with the toner performance being optimized.
[0022]
In the method of the present invention, the charge amount and the particle size of the one-component non-magnetic toner after being regulated by the regulating member are adjusted by adjusting various factors considered in the design of the toner or the developing device. It can be controlled to satisfy. For example, toner design factors include (1) the type, resin composition, and shape of toner base particles; and (2) the type and amount of external additives. The design elements of the developing device include (3) the surface material and surface hardness of the developing roller as the developer carrier; and (4) the material and restricting conditions (such as pressing force) of the restricting blade as the restricting member, and the restricting blade. For example, the amount of toner transported at the time of passage may be used. However, it is usually difficult to uniquely determine the relationship of a> b using any of the elements exemplified in the above (1) to (4). That is, even if one element is specified, the condition fluctuates depending on the relation with other elements, and the relation of a> b may not be realized. Therefore, how to set each element is preferably determined individually and experimentally, and in that case, the conditions described in Examples described later are referred to.
[0023]
The following is a typical example of elements for controlling the particle size distribution and the charge amount distribution of the one-component non-magnetic toner. In the method of the present invention, the particle size distribution and the charge amount distribution can be controlled by selecting from the elements described below. However, the present invention is not limited to these, and can be controlled by adjusting other elements. .
[0024]
<Toner mother particles>
The type of the binder resin of the toner base particles, particularly the polar functional group in the resin, affects the charging characteristics of the toner base particles. Examples of the binder resin include polyester resin, styrene-acrylic copolymer, polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, and styrene-butadiene copolymer. Polymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, epoxy resin, urethane modified epoxy resin, silicone modified epoxy resin, vinyl chloride resin, rosin modified maleic resin, phenyl resin, polyethylene, polypropylene, ionomer Resins, silicone resins, ketone resins, ethylene-ethyl acrylate copolymers, xylene resins, polyvinyl butyral resins, terpene resins, phenolic resins, urethane / urea resins, aliphatic or alicyclic hydrocarbon resins, and the like. That. In the method of the present invention, one or more of known binder resins represented by these can be selected and used.
[0025]
The shape of the toner base particles is preferably close to a spherical and uniform surface structure, and it is preferable that there is little variation in size and shape between the individual base particles. The circularity (spheroidization coefficient) of the toner base particles is preferably 0.91 or more, and the transfer efficiency can be improved. However, the circularity is 0.95 or more so as not to generate the toner of the opposite polarity. It is preferable to adjust so that
[0026]
The toner base particles can be produced by a pulverization method or a polymerization method. The pulverization method toner is obtained by uniformly mixing a pigment, a release agent, and a charge control agent with a binder resin with a Henschel mixer, melting and kneading with a twin-screw extruder, and after cooling, passes through a coarse pulverization-fine pulverization step, and is classified. It is made by processing and further adding a flow improver. In order to adjust the circularity of the pulverized toner, it is preferable to perform a sphering process. In the pulverizing step, if a device capable of pulverizing into a relatively round sphere, for example, a turbo mill (manufactured by Kawasaki Heavy Industries, Ltd.) known as a mechanical pulverizer, is used, the circularity can be reduced to 0.93, and the pulverized toner is further used. By using a commercially available hot air sphering apparatus “Surfering System SFS-3” (manufactured by Nippon Pneumatic Industries, Ltd.), the circularity can be reduced to 1.00.
[0027]
In addition, as a method for preparing a polymerization toner, a suspension polymerization method, an emulsion polymerization method, and the like can be given. In the suspension polymerization method, a polymerizable monomer, a coloring pigment, and a release agent are added as necessary, and a mixture containing a dye, a polymerization initiator, a crosslinking agent, a charge control agent, and other additives is dissolved or dispersed. The obtained monomer composition is added to an aqueous phase containing a suspension stabilizer (a water-soluble polymer, a poorly water-soluble inorganic substance) while stirring, granulated, polymerized, and colored to a desired particle size. Polymerized toner particles can be formed.
[0028]
In the emulsion polymerization method, the circularity of the polymerization toner can be adjusted by controlling the temperature and time in the aggregation process of the secondary particles, so that the circularity can be freely changed. 1.00. On the other hand, in the suspension polymerization method, since a spherical toner is possible, the circularity is in the range of 0.98 to 1.00. Further, by performing heating deformation at a temperature equal to or higher than the glass transition temperature Tg of the toner to adjust the circularity, the circularity can be freely adjusted from 0.94 to 0.98.
[0029]
Further, in any of the pulverized toner and the polymerized toner, the glass transition temperature is in the range of 50 to 100 ° C, preferably 55 to 90 ° C, and the flow softening temperature is 70 to 140 ° C, preferably 75 to 130 ° C. It can be set in the range of ° C.
[0030]
A well-known colorant and charge control agent can be added to the toner base particles in addition to the binder resin. The charge control agent is not particularly limited as long as it can give a positive or negative charge by frictional charging, and various organic or inorganic charge control agents can be used.
[0031]
Examples of the positive charge control agent include Nigrosine Base EX, quaternary ammonium salt P-51, Nigrosine Bontron N-01 (trade name, manufactured by Orient Chemical Industry Co., Ltd.), Sudan Chief Schwarz BB (Solvent Black 3: C No. 26150), Fettschwarz HBN (C.I. No. 26150), Brilliant Spirits Schwarz TN (trade name: Farben-Fabriken Bayer), Zavonschwartz X (trade name: Falberge Hoechst) And alkoxylated amines, alkylamides, molybdate chelate pigments, and the like.
[0032]
Examples of the negative charge control agent include oil black (CI No. 26150), oil black BY (trade name: manufactured by Orient Chemical Industry Co., Ltd.), and Bontron S-22 (trade name: manufactured by Orient Chemical Industry Co., Ltd.). ), Salicylic acid metal complex E-81 (trade name: manufactured by Orient Chemical Co., Ltd.), thioindigo pigment, sulfonylamine derivative of copper phthalocyanine, Spiron Black TRH (trade name: Hodogaya Chemical Co., Ltd.), Bontron S-34 (Trade name: Orient Chemical Co., Ltd.), Nigrosine S0 (trade name: Orient Chemical Co., Ltd.), Celes Schwarz (R) G (trade name: Fuarben Fabriken Bayer), Kromogen Schwarz ET00 (C No. 14645), Azo Oil Black (R) (trade name: manufactured by National Aniline Co.) And the like. These charge control agents can be used alone or in combination of two or more. The amount of the charge control agent added to the binder resin is 0.001 to 5 parts by weight based on 100 parts by weight of the binder resin. Parts by weight (preferably 0.001 to 3 parts by weight).
[0033]
<External additives>
An external additive is also an important factor in controlling the charging characteristics of the toner. As the external additive, organic fine powder or inorganic fine powder can be used. As the organic fine powder, for example, a fluorine resin powder (that is, fine powder of vinylidene fluoride, a fine powder of polytetrafluoroethylene), an acrylic resin fine powder, a metal salt of a fatty acid (that is, zinc stearate, calcium stearate, stearic acid) Lead and the like). Examples of the inorganic fine powder include metal oxides (that is, iron oxide, aluminum oxide, titanium oxide, and zinc oxide), fine powder silica (that is, wet-process silica, dry-process silica, and the like), and these silicas. Examples include surface-treated silica that has been surface-treated with a silane coupling agent, a titanium coupling agent, silicon oil, or the like. These can be used alone or in combination of two or more.
[0034]
<Developing roller>
The developing roller, for example, NBR a surface of a metal pipe having a diameter of about 16~24mm plating or blasting the roller or the center axis peripheral surface,, SBR, EPDM, volume resistivity ¹⁰⁴ made of urethane rubber, silicone rubber or the like One having a conductive elastic layer having a hardness of 10 to 10 ⁸ Ω · cm and a hardness of 40 to 70 ° (Asker A hardness) can be used. The developing roller is configured such that a developing bias voltage can be applied thereto via a shaft or a central shaft of a pipe. The charge amount of the toner particles can be adjusted by selecting the material and processing method of the developing roller, the volume resistance value, hardness, and the like of the elastic layer.
[0035]
<Regulatory blade, regulatory conditions, etc.>
As the regulating blade, for example, SUS, phosphor bronze, a rubber plate, a metal thin plate with a rubber chip bonded thereto, or the like can be used. The work function on the toner contact surface is preferably 4.8 to 5.4 eV, and is preferably smaller than the work function on the toner surface.
[0036]
The pressing force as the regulation condition depends on other conditions, but is preferably set so as to perform thin layer regulation. That is, in the regulation state, the thin layer regulation that regulates the toner on the surface of the developing roller with a pressing force of about one layer makes it possible to uniformly charge each one-component non-magnetic toner particle. The quantity is easier to control. Therefore, it is preferable that the regulating blade presses the developing roller as a developer carrier with a linear pressure of 25 to 50 gf / cm by a biasing means such as a spring or by using a repulsive force as an elastic body.
[0037]
The toner conveyance amount during the regulating blade passes, depending on other ^conditions, it is preferable to set to about ^{0.2mg / cm 2 ~0.4mg / cm 2} . The toner conveyance amount is preferably selected according to the particle size of the toner particles. For example, when the toner particle size is 5 μm, it is about 0.25 mg / cm ² , and when the toner particle size is 7 μm, it is 0.35 mg / cm 2. It is preferable to adjust the transport amount to about ² .
[0038]
By adjusting various elements as described above, it is possible to perform control so as to satisfy the condition of a> b. In addition, the above-described elements are similarly adjusted under the condition that the reverse polarity toner is less than 5% and the condition that the number of toners in the largest charge amount category is 10% or more of the entire toner. This can be achieved by:
[0039]
Hereinafter, a developing device and an image forming apparatus that can be used in the developing method and the image forming method of the present invention will be described with reference to the drawings. The developing method of the present invention can be carried out in either a contact developing system or a non-contact developing system. First, a description will be given of a developing device / image forming apparatus employing a non-contact developing method.
[0040]
FIG. 1 is a schematic cross-sectional view illustrating the entire configuration of a tandem type image forming apparatus 1. The image forming apparatus 1 includes a housing 3, a discharge tray 5 formed on an upper portion of the housing 3, and a door 7 provided on the front surface of the housing so as to be openable and closable. , An image forming unit 11, a blower fan 13, a transfer belt unit 15, and a paper feed unit 17. A paper transport unit 19 is provided in the door 7. The image forming apparatus 1 is a so-called cleaner-less image forming apparatus that does not include a cleaner mechanism for removing waste toner (untransferred toner) on the photosensitive drum 23.
[0041]
The image forming unit 11 includes four image forming stations 21 in which four developing devices that store toners of different colors can be set. The four image forming stations 21 are for yellow, magenta, cyan and black developing devices, respectively, and are distinguished by reference numerals 21Y, 21M, 21C and 21K in the figure. In each of the image forming stations 21Y, 21M, 21C and 21K, a photosensitive drum 23 as an image carrier, a corona charging unit 25 provided around the photosensitive drum 23, and a developing device 100 of the present invention are provided. Have been.
[0042]
The transfer belt unit 15 is stretched between these rollers, a drive roller 27 that is rotationally driven by a drive source (not shown), a driven roller 29 provided diagonally above the drive roller 27, and a tension roller 31. , An intermediate transfer belt 33 circulated in a counterclockwise direction, and a cleaning unit 34 in contact with the surface of the intermediate transfer belt 33.
[0043]
The photosensitive drum 23 is pressed against the belt surface 35 along an arched line, and is driven to rotate in a direction indicated by an arrow in FIG. By adjusting the position of the tension roller 31, the tension of the intermediate transfer belt 33, the curvature of the arch, and the like can be controlled.
[0044]
The drive roller 27 also serves as a backup roller for the secondary transfer roller 39. Further, a rubber layer having a thickness of, for example, about 3 mm and a volume resistivity of 10 ⁵ Ω · cm or less is formed on the peripheral surface of the driving roller 27. It forms a conductive path for the secondary transfer bias supplied via 39. The diameter of the driving roller 27 is smaller than the diameters of the driven roller 29 and the tension roller 31, so that the recording paper after the secondary transfer can be easily separated by the elastic force of the recording paper itself. The driven roller 29 also functions as a backup roller of the cleaning unit 34.
[0045]
The cleaning means 34 is provided on the belt surface 35 facing downward in the transport direction, and removes the toner remaining on the surface of the intermediate transfer belt 33 after the secondary transfer, and a toner transport path for transporting the collected toner. 42. The cleaning blade 41 is in contact with a portion where the intermediate transfer belt 33 is wound around the driven roller 29. A primary transfer member 43 abuts on the back surface of the intermediate transfer belt 33 at a position facing the photosensitive drum 23 of each of the image forming stations 21Y, 21M, 21C and 21K, and a transfer bias is applied to the primary transfer member 43. It is supposed to be.
[0046]
The exposure unit 9 is provided in a space obliquely below the image forming unit 11, and a blower fan 13 is provided obliquely above the image forming unit 11. A paper feed unit 17 is provided below the exposure unit 9. The exposure unit 9 has vertically arranged scanner means 49 including a polygon mirror motor 45 and a polygon mirror 47 at the bottom. A single f-θ lens 51 and a reflection mirror 53 are provided on the optical path B, and a plurality of folds are provided above the reflection mirror 53 such that the scanning optical paths of the respective colors are non-parallel to the photosensitive drum 23 and fold. A mirror 55 is provided.
[0047]
In the exposure unit 9, an image signal corresponding to each color is emitted from the polygon mirror 47 by a laser beam modulated and formed based on a common data clock frequency, and passes through an f-θ lens 51, a reflection mirror 53, and a folding mirror 55. The latent image is formed on the photosensitive drums 23 of the image forming stations 21Y, 21M, 21C and 21K.
[0048]
The blower fan 13 functions as a cooling unit, which guides air in the direction of the arrow in FIG. 1 and discharges heat from the exposure unit 9 and other heat generating units.
[0049]
The paper supply unit 17 includes a paper supply cassette 57 on which the recording media P are stacked, and a pickup roller 59 for feeding the recording media P from the paper supply cassette 57 one by one. The sheet transport unit 19 includes a gate roller pair 61 that regulates the timing of feeding the recording medium P to the secondary transfer unit, a secondary transfer roller 39 that is pressed against the drive roller 27 and the intermediate transfer belt 33, and a fixing unit 63. , A discharge roller pair 65, and a conveyance path 67 for double-sided printing.
[0050]
The fixing means 63 includes a rotatable fixing roller pair 69 having a heating element such as a halogen heater built in at least one side, and presses and biases at least one of the fixing roller pairs 69 to the other side to secondarily form the sheet material. Pressing means for pressing the transferred secondary image against the recording medium P, and the secondary image secondary-transferred onto the recording medium is fixed to the recording medium at a predetermined temperature at a nip formed by the fixing roller pair 69. Is done.
[0051]
The above is the schematic configuration of the tandem type image forming apparatus 1 that can be used in the method of the present invention, and the developing apparatus 100 is set and used in each of the image forming stations 21Y, 21M, 21C and 21K. In FIG. 1, the developing devices of the respective colors are denoted by reference numerals 100Y, 100M, 100C and 100K in correspondence with the colors of the toner of the developing devices, similarly to the respective image forming stations. Since the configurations of these developing devices are basically the same, the configuration of a general developing device 100 will be described below with reference to FIG.
[0052]
FIG. 2 is a sectional view of the developing device 100. The developing device 100 includes a housing 103 in which a substantially cylindrical toner accommodating portion 101 is formed. The housing 103 is provided with a supply roller 105 and a developing roller 107. As shown in FIG. 1, when the developing device 100 is set in the image forming station, the developing roller 107 is adjacent to the photosensitive drum 23 at a small interval (for example, 100 to 300 μm). Has a function of developing the latent image formed on the photosensitive drum 23 with the toner supplied to the peripheral surface of the developing roller 107 while rotating in the direction opposite to the rotation direction (see the arrow in the figure). In such a developing operation, a developing bias in which an AC voltage is superimposed on a DC voltage is applied to the developing roller 107 from a developing bias power supply (not shown), and an oscillating voltage is applied between the developing roller and the photosensitive drum. This is performed by supplying toner from the developing roller 107 to the electrostatic latent image portion formed on the photosensitive drum 23.
[0053]
The supply roller 105 has a surface formed of urethane sponge, and is rotatable in the same direction as the developing roller 107 (counterclockwise in FIG. 2) in a state where the peripheral surface of the supply roller 105 is in contact with the developing roller 107. . A voltage equivalent to the developing bias voltage applied to the developing roller 107 is also applied to the supply roller 105.
[0054]
A regulating blade 109 is constantly pressed against the developing roller 107 by the action of the leaf spring member 111 and an elastic member 112 provided thereunder so as to be uniform over the longitudinal direction of the peripheral surface of the developing roller 107. In addition, an excess amount of toner attached to the peripheral surface of the developing roller 107 is scraped off so that a fixed amount of toner is carried on the peripheral surface of the developing roller 107. The regulating blade 109 also has a function of appropriately charging the toner 113. Therefore, the charge amount can be controlled by changing the pressing force of the regulating blade 109 and the materials of the developing roller 107 and the regulating blade 109.
[0055]
The scraped toner drops naturally and is mixed into the toner 113 in the toner storage unit 101. This will be described in detail later. On the upper side of the peripheral surface of the developing roller 107, the other end of a seal member 115, one end of which is fixed to the housing 103, is in pressure contact with the sealing member 115 to prevent the toner 113 in the housing 103 from scattering to the outside. I have.
[0056]
An agitator 119 that rotates in the clockwise direction in FIG. 2 around the rotation shaft 117 is provided in the toner storage unit 101. The agitator 119 includes two arm members 121 extending in opposite directions about the rotation shaft 117, and each of the arm members 121 is set to have a dimension slightly shorter than the diameter of the circle of the cross section of the toner container 101. A stirring fin 123 extends from the tip of each arm member 121 in a direction opposite to the rotation direction of the agitator 119. The stirring fin 123 is formed of a flexible sheet member, and the leading end thereof is in pressure contact with the inner peripheral surface of the cylindrical toner storage unit 101 by the elastic force due to the flexibility. With this configuration, when the agitator 119 rotates, the toner 113 existing in the area 125 between the inner peripheral surface of the toner container 101 and the stirring fin 123 is scraped up by the stirring fin 123, and a toner guide to be described later is formed. It can be transported onto a member.
[0057]
The upper surface 114 of the toner 113 accommodated in the toner accommodating portion 101 is set at a position lower than the position 127 where the regulating blade 109 is in contact with the peripheral surface of the developing roller 107. This is because if the amount of toner is large enough to bury the regulating blade 109, the toner scraped off by the regulating blade 109 will be present near the regulating blade. Also, the function of the regulating blade 109 for scraping off excess toner from the developing roller 107 to regulate the amount of toner to be conveyed to the developing area and the function of appropriately charging the toner are hindered.
[0058]
In the developing device 100, the position of the upper surface 114 of the toner 113 stored in the toner storage unit 101 is below the lower end of the regulating blade 109, and the upper limit of the position of the intersection 128 between the leaf spring member 111 and the elastic member 112. Is set as If the position of the upper surface 114 of the toner 113 in the toner storage unit 101 is higher than the intersection point 128, there is a possibility that the movement of the leaf spring member 111 may be restricted, so that an appropriate regulation pressure may not be obtained. . As a result, the "function of carrying a fixed amount of toner on the peripheral surface of the developing roller 107" and the "function of properly charging the toner" may be hindered. However, by setting the upper limit of the position of the upper surface 114 of the toner 113 to the position of the intersection 128 as described above, the functions are not hindered. As described above, it is possible to send out the toner having the desired particle size distribution and charge amount distribution also by the structural adjustment of the developing device 100 (particularly, the vicinity of the regulating blade 109).
[0059]
Between the point 127 where the regulating blade 109 is in contact with the peripheral surface of the developing roller 107 and the upper surface 114 of the toner 113 accommodated in the toner accommodating portion 101, the toner is inclined at an inclination angle equal to or larger than the repose angle of the toner 113. Is formed as a part of the housing 103. The toner guide surface 129 has a function of guiding the toner 113 scraped off from the peripheral surface of the developing roller 107 by the regulating blade 109 to the toner storage unit 101 side.
[0060]
Below the portion 127 where the regulating blade 109 is in contact with the peripheral surface of the developing roller 107, the toner 113 scraped off from the peripheral surface of the developing roller 107 by the regulating blade 109 is guided to the toner container 101. A guide space 131 is formed.
[0061]
Above the toner container 101, a toner guide member 133 is provided. The toner guide member 133 is provided at an end portion 134 on a side away from the supply roller 105, and has a sharply formed scraper 135 for scraping the toner 113 conveyed by the stirring fins 123, and a smaller angle than the scraper 135. On the supply roller 105 side, the upper surface side is inclined at an angle equal to or larger than the angle of repose of the toner 113 and is formed in a planar manner, and is formed on the downstream side of the flat conveyance unit 137, and the upper surface side forms a concave curved surface. And a contact portion 143 that is in contact with the peripheral surface of the supply roller 105 at an appropriate linear pressure on the downstream side of the curved portion 141. The surface roughness of the toner guide member 133 including the flat transport portion 137, the curved portion 141, and the contact portion 143 is formed to be smaller than the average particle diameter of the toner.
[0062]
In addition, the presence of the contact portion 143 prevents the toner 113 attached to the lower surface of the supply roller 105 from falling due to gravity, thereby preventing a decrease in image density due to a decrease in the amount of toner that can be supplied to the developing roller 107. can do. Further, between the curved portion 141 and the peripheral surface of the supply roller 105, a temporary storage portion 139 of the toner whose cross section narrows in a wedge shape is formed.
[0063]
In the toner guide member 133 having such a shape, after the toner 113 conveyed by the stirring fins 123 is scraped off by the scraper 135, the toner 113 is moved along the flat conveyance portion 137, in the width direction thereof, and in the inclination thereof. At an arbitrary point in the direction, the toner particles fall by gravity at a uniform speed, and are temporarily stored in the temporary storage section 139 of the toner. In the temporary storage portion 139 of the toner that narrows in a wedge shape, the pressing force against the peripheral surface of the supply roller 105 gradually increases as the toner 113 advances to the narrow region. Is pressed, so that the toner 113 is easily carried on the peripheral surface. When the toner 113 is pushed out beyond the contact portion 143, the toner 113 falls down the toner guide space 131 and is returned to the toner container 101 directly or guided by the toner guide surface 129.
[0064]
Next, image formation in the image forming apparatus 1 and the developing apparatus 100 will be described. Image formation is performed as follows.
That is, when an image forming signal is input from a computer or the like (not shown), the photosensitive drum 23, the developing rollers 107 of the image forming stations 21Y, 21M, 21C, and 21K and the intermediate transfer belt 33 are driven to rotate. Next, the outer peripheral surface of the photosensitive drum 23 is uniformly charged by the corona charging means 25, and the outer peripheral surface is selectively exposed by the exposure unit 9 in accordance with the image information of the first color. A latent image is formed. The toner 113 stored in the toner storage unit 101 is scraped by the stirring fin 123 by the rotation of the agitator 119 in the area 125 between the inner peripheral surface of the toner storage unit 101 and the stirring fin 123. . The scraped-up toner 113 is scraped off by a scraper 135, slides down the flat transport section 137, and reaches the toner storage section 139. The toner 113 accumulated in the toner storage section 139 is sequentially carried on the peripheral surface of the supply roller 105, and then the toner moves to the developing roller 107 side, and excess toner is scraped off by the regulating blade 109 and The toner carried on the toner 107 is charged by the regulating blade 109, and the toner develops the electrostatic latent image formed on the photosensitive drum 23. At this time, toner is applied to the photosensitive drum 23 from the developing roller 107 of the image forming station 21Y, whereby a yellow electrostatic latent image toner image is formed on the photosensitive drum 23. Further, after this toner image is transferred onto the intermediate transfer belt 33 to which a temporary transfer voltage having a polarity opposite to the charging polarity of the toner is applied, the outer peripheral surface of the photosensitive drum 23 is gradually charged by the charging device.
[0065]
A similar operation is repeated corresponding to the second, third, and fourth colors of the image forming signal, and the latent image formation and development by one rotation of the photosensitive drum 23 and the intermediate transfer belt 33 are repeated. The corresponding four color toner images are superimposed and transferred on the intermediate transfer belt 33. Then, this full-color image is further transferred onto a recording medium.
[0066]
Next, an example of a full-color image forming apparatus 200 including a developing device employing a contact developing method will be described with reference to FIG. This full-color image forming apparatus 200 develops four colors of Y for yellow, C for cyan, M for magenta, and K for black around the photosensitive drum 23 along the rotation direction to develop an electrostatic latent image. Developing device units 221Y, 221C, 221M and 221K composed of devices are arranged. 3, reference numeral 107 denotes a developing roller, reference numeral 109 denotes a regulating blade, reference numeral 233 denotes a housing, reference numeral 236 denotes a blade supporting member, reference numeral 237 denotes a blade pressing spring, reference numeral 238 denotes a developing cover, and reference numeral 239 denotes a stirring shaft. Although not shown here, as in FIG. 1, a charging roller as a charging unit, an exposure unit for forming an electrostatic latent image on the photosensitive drum 23, and a toner image formed on the photosensitive drum 23 are intermediately transferred. An intermediate transfer device for transferring onto the belt is arranged. The image forming apparatus 200 differs from the image forming apparatus 1 of FIG. 1 in that it includes a cleaning device (not shown) for removing toner remaining on the photosensitive drum 23.
[0067]
The photosensitive drum 23 has a thin cylindrical cylindrical conductive substrate and a photosensitive layer formed on the surface thereof, and is driven to rotate by driving means (not shown). The developing device units 221Y, 221C, 221M, and 221K are arranged to be swingable with respect to the photosensitive drum 23, and only the developing roller 107 of one developing device contacts the photosensitive drum 23 for each rotation of the photosensitive drum 23. It is configured to be accessible.
[0068]
In image formation, when an image forming signal is input from a computer or the like (not shown), the photosensitive drum 23, the developing rollers of the developing device units 221Y, 221C, 221M, and 221K and the intermediate transfer belt are driven to rotate. First, the outer peripheral surface of the photosensitive drum 23 is uniformly charged by the charging roller, and the outer peripheral surface is selectively exposed by the exposure unit in accordance with the image information of the first color to form, for example, a yellow electrostatic latent image. Is done. At this time, only the developing roller 107 of the yellow developing device unit 221Y comes into contact with the photosensitive drum 23, whereby a yellow electrostatic latent image toner image is formed on the photosensitive drum 23. Further, the toner image is transferred onto an intermediate transfer belt to which a temporary transfer voltage having a polarity opposite to the charging polarity of the toner is applied, and the toner remaining on the photosensitive drum 23 is removed by a cleaning device. The outer peripheral surface of the drum 23 is gradually charged by the charging device.
[0069]
The same operation is repeated for the second, third, and fourth colors of the image forming signal, and the latent image formation and development by one rotation of the photosensitive drum 23 and the intermediate transfer belt are repeated, and according to the content of the image forming signal. The four color toner images are superimposed and transferred on the intermediate transfer belt. Then, this full-color image is further transferred onto a recording medium.
[0070]
In the above-described image forming apparatus 200 employing the contact type developing method of FIG. 3, similarly to the case of the image forming apparatus 1 of FIG. 1, by adjusting the configuration of the regulating blade 109 and the like, structurally from the developing apparatus side. The charge amount and the like can be controlled.
[0071]
[Action]
As a result of intensive studies on the charging characteristics of the one-component non-magnetic toner, it is important that the charge amount distribution of a certain toner set be understood in relation to the particle size distribution of the toner set. It has been found that when the distribution satisfies a certain relationship with the particle size distribution, the charging on the toner surface is uniform.
[0072]
That is, in the method of the present invention, it is necessary to control so as to satisfy the relationship of a> b. Under this condition, the reason why a good image can be formed has not been elucidated yet. However, when the above condition is satisfied, when focusing on the surface of one toner particle, the surface charge distribution is reversely charged (for example, It is assumed that uniform ideal charging without uneven distribution of the positively charged portion on the surface of the negatively charged toner is performed. As a result, problems such as image defects due to uneven toner such as fogging, scattering, and transfer dust can be minimized.
[0073]
In addition, since the uniformly charged toner occupies the majority, the transfer efficiency is also close to 100%, and the possibility of realizing a cleanerless and less waste toner process is enhanced. Therefore, it is possible to simplify the conventional process, and to provide an innovative image forming method that achieves both miniaturization and high image quality of the apparatus.
[0074]
【Example】
Next, the present invention will be described in more detail with reference to Examples and Test Examples, but the present invention is not limited thereto.
[0075]
The particle size and charge amount of the toner in the following examples and comparative examples were measured by the following operation procedure using an ESPART Analyzer (registered trademark) model EST-3 (manufactured by Hosokawa Micron Corporation).
[0076]
<Measurement procedure using EAS part analyzer>
(1) After turning on the main power of the device, wait 30 minutes until the device is stabilized.
(2) The supply pressure of the nitrogen gas cylinder is set to 0.3 MPa. The personal computer (PC) for data processing is started, and “ESTWIN902.exe” is started. At this time, the particle size is set to 60 channels. Next, particle size calibration is performed. (3) Adjust the constant part suction flow rate to 0.4 liter / min.
(4) Adjust the dust collection air flow rate to 0.4 liter / min.
(5) 150 ml of pure water and three drops of the PSL dispersion are added to a nebulizer bottle, and after stirring, the mixture is placed in an ultrasonic washer and the standard solution is dispersed for 2 minutes.
(6) Attach a dryer containing silica gel and a nitrogen gas supply pipe to the nebulizer bottle.
(7) Turn on the calibration switch and wait for 30 seconds until the gas supply is stabilized.
(8) Adjust the gas pressure to 0.08 Mpa.
(9) Click Start on the PC measurement screen to start the measurement.
(10) After completion of the measurement, confirm that the value of D50 count and D50 volume is 3.16 ± 0.1 μm (the measured value depends on the particle size of the PSL standard solution).
[0077]
(11) Next, the supply hood and the nozzle of the one-component supply device are set, and charging calibration is performed.
(12) Set the developing roller on which the toner layer has been formed in the one-component supply device.
(13) Adjust the distance between the developing roller and the nozzle to 4 mm.
(14) As the charging calibration measurement conditions, the suction flow rate = 0.4 L / min, the dust collection flow rate = 0.4 L / min, the interval = 1 second, the blow time = 1 second, the gas pressure = 0.08 MPa, X Axial feed speed = 0.1 mm / sec, no electric field voltage is applied.
(15) Check that “Q / m” on the measurement screen is 0 ± 0.5 μC / g.
[0078]
(16) Sample measurement:
The developing roller on which the toner layer has been formed is set in a one-component supply device. The measurement conditions are shown below.
Distance between developing roller and nozzle 4 mm, suction flow rate = 0.2 l / min, dust collection flow rate = 0.6 l / min, interval = 3 seconds, blow time = 1 second, gas pressure = 0.02 MPa, electric field voltage = 0.1kV
The total count is not limited, but is preferably 300 or more and 3000 or less. At this time, it is important to remove the toner so that the base of the developing roller can be seen after the measurement, and to perform the measurement.
(17) Data processing:
The individual data of the particle size and the charge amount measured by the above method were processed as follows. Using commercially available software [here, the macro function of EXCEL (registered trademark: manufactured by Microsoft Corporation) is used], the particle size is divided into 0 μm to 10 μm into 0.5 μm intervals, and 0 μm to 0.5 μm. Less than 0.5 μm to less than 1.0 μm (the same applies hereinafter), and the indication is 0.25 μm for the category of 0 μm to less than 0.5 μm and 0.75 μm for the category of 0.5 μm to less than 1.0 μm , ... (the same applies hereinafter).
Similarly, regarding the charge amount, 0 fC or more and less than 0.5 fC, 0.5 fC or more and less than 1.0 fC, -0.5 fC or more and less than 0 fC, -1.0 fC or more and less than -0.5 fC ... And the same). As a display, a section from 0 to less than 0.5 fC is 0.25, a section from 0.5 fC to less than 1.0 fC is 0.75..., And a section from -0.5 to less than 0 fC is -0. 25, -1.0fC or more and less than -0.5fC were classified into -0.75 ... (the same applies hereinafter).
[0079]
Example 1
A monomer mixture consisting of 80 parts by weight of a styrene monomer, 20 parts by weight of butyl acrylate, and 5 parts by weight of acrylic acid was mixed with 105 parts by weight of water, 1 part by weight of a nonionic emulsifier, 1.5 parts by weight of an anionic emulsifier, and potassium persulfate. The mixture was added to a water-soluble mixture consisting of 0.55 parts by weight, and stirred at 70 ° C. for 8 hours under a nitrogen stream. After the polymerization reaction, the mixture was cooled to obtain a milky white resin emulsion having a particle size of 0.25 μm.
[0080]
Next, 200 parts by weight of this resin emulsion, 20 parts by weight of a polyethylene wax emulsion (manufactured by Sanyo Chemical Industries, Ltd.), and 7 parts by weight of phthalocyanine blue, and 0.2 part by weight of sodium dodecylbenzenesulfonate as a surfactant were contained. After dispersing in water and adjusting the pH to 5.5 by adding diethylamine, 0.3 parts by weight of aluminum sulfate as an electrolyte was added with stirring, followed by high-speed stirring with a TK homomixer to perform dispersion. Further, 40 parts by weight of a styrene monomer, 10 parts by weight of butyl acrylate, and 5 parts by weight of zinc salicylate were added together with 40 parts by weight of water, and the mixture was heated to 90 ° C. while stirring under a nitrogen stream, and hydrogen peroxide was added. And polymerized for 5 hours to grow particles. After the termination of the polymerization, the temperature was raised to 95 ° C. while adjusting the pH to 5 or more and maintained for 5 hours in order to improve the bonding strength of the associated particles. Thereafter, the obtained particles were washed with water and vacuum dried at 45 ° C. for 10 hours.
[0081]
0.7% by weight of large particle size silica (manufactured by Nippon Aerosil Co., Ltd .: RX50) and small particle size silica (manufactured by Nippon Aerosil Co., Ltd.) (RX300) 1.0% by weight and titanium (manufactured by Titanium Co., Ltd .; STT30S) 0.5% by weight were added, and a small stirrer was used to perform a rotation speed of 2000 rpm and a processing time of 2 minutes.
[0082]
The toner thus obtained was negatively charged in the same non-contact developing device as in FIG. The transport amount when passing through the regulating blade was 0.35 mg / cm ² . The particle size and charge amount of about 3000 of the charged toner particles were measured. Table 1 shows the results. From Table 1, it can be seen that the particle size a [μm] of the largest number particle size distribution in the particle size distribution of the toner, and the particle size b [μm] of the largest particle size distribution in the particle size distribution for each charge amount classification. Is a = 5.25 (682 sections), b = 4.75 (332 sections), and a> b. In addition, in the case of the toner of the present embodiment, as can be seen from Table 1, the number of the positively charged toner serving as the opposite polarity toner was 123 out of 2994, which was 4.1%. Further, the largest number of toners in the charge amount category in the charge amount distribution for each particle size category was 332, which was 10% or more of the entire toner.
[0083]
[Table 1]

[0084]
Next, using the same developing device, a toner image was formed on the photosensitive member by superimposing Vdc = 300 V as a DC component and Vpp 1.3 Kv as an AC component in a non-contact manner. As a result, the developing efficiency was 90% or more. It was possible to form an image with almost no occurrence of cavities and scattering. Further, when an image was formed using the image forming apparatus shown in FIG. 1, the primary transfer efficiency from the photosensitive member to the intermediate transfer medium was 99.9% or more, the waste toner was reduced, and the cleanerless image forming apparatus was used. Image formation (cleanerless process) was realized.
[0085]
Example 2
Using the same toner base particles as in Example 1 and using, as an external additive, 0.5% by weight of silica (manufactured by Nippon Aerosil Co., Ltd .; RX50) having a primary particle size of 40 nm and treated with hexamethyldisilazane (hereinafter referred to as "HMDS"). %, And 0.5% by weight of HMDS-treated silica (RX300, manufactured by Nippon Aerosil Co., Ltd.) having a primary particle diameter of 7 nm, and a toner was produced in the same manner as in Example 1.
[0086]
After the toner was negatively charged in the same manner as in Example 1, the particle size distribution and the charge amount distribution were measured. Table 2 shows the results. From Table 2, it can be seen that the particle size a [μm] of the particle size distribution having the largest number in the particle size distribution of the toner, and the particle size b [μm] of the particle size distribution having the largest number in the particle size distribution for each charge amount classification. Is a = 6.25 (680 sections) and b = 5.25 (197 sections), which satisfies the condition of a> b.
[0087]
[Table 2]

[0088]
Comparative Example 1
A toner was prepared in the same manner as in Example 1 except that a resin X different from that in Example 1 was used as the resin of the toner base particles. This toner was negatively charged in a non-contact developing device in the same manner as in Example 1. The particle size and charge amount of about 3000 of the charged toner particles were measured. Table 3 shows the results. From Table 3, the particle size a [μm] of the largest number particle size distribution in the particle size distribution of the toner and the particle size b [μm] of the largest particle size distribution in the particle size distribution for each charge amount classification are shown. Is a = 4.75 (1076 sections) and b = 4.75 (372 sections), which does not satisfy the condition of a> b.
[0089]
[Table 3]

[0090]
Further, when development was performed using this toner in the same manner as in Example 1, almost no development could be performed even when the bias voltage was increased to 500V.
[0091]
Comparative Example 2
A toner was prepared in the same manner as in Example 1 except that a resin Y different from that in Example 1 was used as the resin of the toner base particles. This toner was negatively charged in a non-contact developing device in the same manner as in Example 1. The particle size and charge amount of about 3000 of the charged toner particles were measured. Table 4 shows the results. From Table 4, it can be seen that the particle size a [μm] of the largest number particle size distribution in the particle size distribution of the toner, and the particle size b [μm] of the largest number particle size distribution in the particle size distribution for each charge amount classification. Is a = 4.75 (1245 sections) and b = 4.75 (409 sections), which does not satisfy the condition of a> b.
[0092]
[Table 4]

[0093]
When development was performed using this toner in the same manner as in Example 1, although the development efficiency was 80%, fogging occurred and a good image could not be formed. Further, the primary transfer efficiency to the photoreceptor was as good as 99.9%. However, when color superposition was performed, reverse transfer toner was generated, and cleanerlessness could not be realized.
[0094]
Example 3
A toner was prepared in the same manner as in Example 1 except that toner base particles having a number average particle size of 5 μm were used, and only 0.1% by weight of small particle size silica (manufactured by Nippon Aerosil Co., Ltd., RX300) was used as an external additive. Created. This toner was negatively charged in the same manner as in Example 1, and the particle size and charge amount were measured for about 3000 charged toner particles. Table 5 shows the results. Table 5 shows that the particle size a [μm] of the largest number of particle size distributions in the particle size distribution of the toner and the particle size b [μm] of the largest number of particle size distributions in the particle size distribution for each charge amount classification. Is a = 4.75 (746 sections), b = 3.75 (229 sections), and a> b.
[0095]
[Table 5]

[0096]
Comparative Example 3
A toner was prepared in the same manner as in Example 1 except that a resin Z different from that of Example 1 was used as the resin of the toner base particles. In the same manner as in Example 1, negative charging was performed in a non-contact developing device. However, the conveyance amount when passing through the regulating blade was 0.6 mg / cm ² . The particle size and charge amount of about 3000 of the charged toner particles were measured. Table 6 shows the results. From Table 6, the particle size a [μm] of the largest number particle size distribution in the particle size distribution of the toner and the particle size b [μm] of the largest number particle size distribution in the particle size distribution for each charge amount classification are shown. Is a = 5.25 (804 sections) and b = 5.25 (212 sections), which does not satisfy the condition of a> b.
[0097]
[Table 6]

[0098]
When development was performed using this toner in the same manner as in Example 1, the development efficiency was 40% or less, and fogging and scattering occurred.
[0099]
As described above, the present invention has been described with respect to various embodiments, but the present invention is not limited to the above embodiments, and can be applied to other embodiments within the scope of the invention described in the claims. It is.
[Brief description of the drawings]
FIG. 1 is a drawing showing an example of an image forming apparatus that can be used in the developing method of the present invention.
FIG. 2 is a drawing showing an example of a developing device that can be used in the developing method of the present invention.
FIG. 3 is a drawing showing another example of an image forming apparatus that can be used in the developing method of the present invention.
[Explanation of symbols]
1 image forming apparatus, 11 image forming units, 21 image forming stations,
23 photosensitive drum, 25 corona charging means, 100 developing device,
101 toner container, 103 housing, 105 supply roller,
107 developing roller, 109 regulating blade, 111 leaf spring member,
112 elastic member, 113 toner, 114 toner upper surface,
115 Sealing member, 119 Agitator, 123 Stirring fin 125 Region between inner peripheral surface of toner container and stirring fin 127 Location where regulating blade abuts on peripheral surface of developing roller 129 Toner guide surface, 131 Toner guide space Department,
133 toner guide member,
134 an end of the toner guide member on the side remote from the supply roller;
135 scraper, 137 flat transport section, 139 temporary storage section for toner,
141 curved part, 143 contact part, 147 seal side wall,
149 contact sheet, 153 shutter member,
155 toner amount monitoring sensor, 157 coil spring,
159 solenoid valve, 161 rotation fulcrum, 163 rotation axis

Claims (5)

The one-component non-magnetic toner carried on the developer carrier is pressed and regulated by the regulating member and charged, and then applied to an electrostatic latent image formed on the image carrier to be visualized as a toner image. Developing method,
For the one-component non-magnetic toner after being regulated by the regulating member, when the particle size and charge amount of each toner particle are measured by a laser Doppler method in a vibration field in an acoustic relaxation cell,
The particle size a [μm] of the largest number of particle size distributions in the particle size distribution of the one-component non-magnetic toner and the particle size b [μm] of the largest number of particle size distributions in the particle size distribution for each charge amount classification. A developing method wherein the relationship is controlled such that a> b. 2. The developing method according to claim 1, wherein the development is performed while controlling the ratio of the opposite polarity toner in the measured charge amount distribution of the one-component non-magnetic toner to be less than 5%. 3. The developing method according to claim 2, wherein the development is performed by controlling the number of toners in the charge amount group having the largest number in the charge amount distribution for each particle size section to be 10% or more of the entire toner. . An image forming method, comprising: transferring a toner image visualized by the developing method according to any one of claims 1 to 3 on the image carrier to form an image. 5. The image forming method according to claim 4, wherein an image forming apparatus having no cleaner mechanism for cleaning waste toner remaining on the image carrier after transfer is used.

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