JP2006301130A - Electrostatic image developer and method for manufacturing the developer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic image developer the charge amount of which rapidly reaches a saturation value with a small amount of friction and shows little change when friction is repeated. <P>SOLUTION: The electrostatic image developer comprises (α) a single toner for electrostatic image development in a particle state essentially comprising thermoplastic color resin particles, or (α) the above toner for electrostatic image development in a particle state essentially comprising thermoplastic color resin particles and (β) a triboelectric member in a particle state for triboelectric charging of the toner particles for electrostatic image development, wherein composite particles comprising carrier particles having 1 nm to 10 μm particle diameter and a charge controlling agent are externally added to the developer. The charge controlling agent particles depositing on the triboelectric member are charged, and the charged charge controlling agent particles move by the agitating effect in a developer agitating device to the surface of the color particles to charge the color resin particles. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dry electrostatic image developer for visualizing an electrostatic latent image and a method for producing the same.

  Generally, a dry electrostatic image developing toner is a two-component developer mixed with a particulate frictional charging member called a carrier, or the toner is layered on a developing roll while rubbing with a control blade or the like. It is used as a one-component developer used by adhering. In the one-component developer, the control blade and the developing roll function as a frictional charging member that imparts frictional charge to the toner. The toner adhering to the surface of the carrier particles, the developing roll, or the control blade (hereinafter referred to as a friction charging member such as a carrier) is desired by friction with the carrier surface or friction with the control blade pressed against the developing roll. Since the amount of charge is acquired, when it is brought into contact with an electrostatic latent image formed on a photoreceptor, a visible image corresponding to the latent image charge can be obtained on the photosensitive surface. In the electrophotographic process, the above-described electrostatic latent image visualization step is an important step called a development step.

  The developed image thus obtained is transferred onto paper or the like, and when this transferred image is brought into contact with a heat roll, the toner is melted by heat and fused onto the paper, and a fixed toner image is obtained on the paper. On the other hand, the photosensitive member is cleaned to form an electrostatic latent image again, and similarly, the development / transfer process is repeated to print a toner image fixed on the transfer paper.

  In the electrophotographic process, each process of electrostatic latent image formation-development-transfer-cleaning-electrostatic latent image formation-- is repeated, and the transfer image obtained on the transfer paper by the transfer process is thermally fixed. Then comes out of the copying machine.

  In the electrophotographic process, the image obtained on the transfer paper is required to be almost the same as the initial one even after repeating the above steps for several tens of thousands of cycles. The toner particles used must maintain a certain amount of triboelectric charge and adhere to the toner particles faithfully according to the electrostatic latent image charge.

  However, the charge amount of the toner particles is obtained by friction with a frictional charging member such as carrier particles for imparting charge to the toner particles, and in order to obtain a uniform transfer image, reproducibility of the charged charge of the toner particles is ensured. It is linked to the most difficult task to achieve.

  In general, as one method for securing the triboelectric charge amount of electrostatic image developing toner, a charge control agent is kneaded into the toner. The charge control agent is often an organic substance having a large number of functional groups or salts of these functional groups in the molecule, and is electrostatically kneaded, pulverized and classified together with the thermoplastic resin and pigment as the main component of the toner. An image developing toner is produced. The triboelectric charge amount of the toner in which the charge control agent is kneaded into the toner is significantly faster than the non-kneaded toner, and the stable triboelectric charge amount can be secured. , The triboelectric charging characteristics are remarkably improved. However, when the electrostatic image developing toner rubs against a frictional charging member such as a carrier for a long time or the development process is repeated, the amount of charge gradually decreases, resulting in a problem that often the desired development image quality cannot be secured. Has occurred.

  As another method for stabilizing the triboelectric charge amount of the electrostatic image developing toner, there is an addition of an external additive. As the external additive, organic or inorganic ultrafine particles having a particle size of about several tens of nm to 1 μm are used, and several parts by weight are generally externally added to 100 parts by weight of the electrostatic image developing toner. When toner containing an external additive comes into contact with a friction charging member such as a carrier, a certain amount of triboelectric charge is secured with the friction charging member, and is detached from the carrier surface while adhering to the toner surface during development. Therefore, charging of the external additive contributes to toner charging.

  In general, the triboelectric charge amount of powder increases in proportion to its specific surface area, so that the ultrafine particles such as external additives have a very large charge amount per unit weight. When the toner surface is coated after the external additive particles come into contact with the carrier surface, the toner charge amount is increased by the amount of charge brought in by the external additive particles. Therefore, the external additive can be regarded as one of substances having a charge control effect. However, even when an external additive is added, if it is rubbed with a frictional charging member such as a carrier for a long time, contamination with the toner surface or the material constituting the carrier surface proceeds, it is buried in the carrier surface, or externally added during development. Since the agent preferentially moves to the latent image surface, the original charge control function cannot be maintained. As a result, the initial charge control effect is gradually lost, eventually causing a problem that the amount of frictional charge of the toner is lowered and the desired development image quality cannot be maintained.

  The present invention has been made to solve the above-described problems in frictional charging of electrostatic image developing toner. With the start of the friction operation, the charged amount rapidly reaches a saturation value with a small amount of friction, and then the friction is reduced. An object of the present invention is to provide an electrostatic image developer that has a very small change in charge amount when it is repeated.

  Further, according to the present invention, the charge amount of the electrostatic image developing toner newly replenished with the development quickly reaches the saturation charge amount value of the electrostatic image developing toner which originally existed, and the consumption of the electrostatic image developing toner is increased. It is an object of the present invention to provide an electrostatic image developing toner that minimizes the change in the charge amount of the electrostatic image developing toner due to the addition.

  Furthermore, in the present invention, the amount of the charge control agent existing between the surface of the electrostatic image developing toner particles and the surface of the friction charging member such as a carrier is kept within a certain range, and the change in the charge amount when the friction is repeated as much as possible. An object is to provide a developer for reducing the size.

  As a result of intensive studies to provide the above-mentioned conventional electrostatic image developing toner, the present inventor has added a composite particle composed of carrier particles and a charge control agent to the developer. It has been found that an electrostatic image developing toner can be obtained in which the above-mentioned problems are solved, the charge rises quickly, and a constant desired charge amount can be secured over a long period of time even when friction is repeated.

  That is, the electrostatic image developer of the present invention is either (a) a particulate electrostatic image developing toner mainly composed of thermoplastic colored resin particles, or (a) a particulate form mainly composed of thermoplastic colored resin particles. And (b) a particle-shaped frictional charging member for frictionally charging the particles of the electrostatic image developing toner. A composite particle comprising 10 μm carrier particles and a charge control agent is externally added.

  The colored resin particles in the present invention are colored resin particles having a particle size of 2 to 20 μm and a volume average particle size of about 5 to 10 μm, which are obtained by including the colored resin particles in the thermoplastic resin particles, and have heat melting characteristics and separation properties. Particles containing wax or the like to improve moldability, and particles with ultrafine silica powder added externally to improve flowability are also included in this category. The colored resin particles can be obtained by a pulverization method obtained by melt-kneading thermoplastic particles, a colorant, wax, and the like, and then pulverizing and classifying them to obtain particles of a desired particle size, and adding silica powder or the like thereto. In addition, like particles called chemical toners, a colorant and wax are dispersed in a monomer, and the dispersion is suspended and polymerized in water. Fine particles of thermoplastic resin, colorant and wax dispersed in water are used. It can also be obtained by agglomerating or emulsifying resin particles and wax particles and a colorant.

  As the particulate frictional charging member such as a carrier in the present invention, a sintered body of ferrite having a substantially spherical shape and a particle size of 20 μm to 200 μm, iron powder, glass beads, etc. are used, and an acrylic resin is used on the surface thereof. A resin, silicone resin, fluororesin, or the like coated with conductive particles such as carbon black to control the chargeability is used. When a particulate frictional charging member is not used, a rubber roll, a metal roll, or the like that has been surface-treated with the same material as the frictional charging member described above is used. In this case, the electrostatic image developer is frictionally charged by being pressed against the surface of these rolls with a blade in the development process.

  The charge control agent particles constituting the composite particles in the present invention are generally composed mainly of organic matter, and have a high density in the molecule such as carbonyl group, acidic hydroxyl group, halogen group, nitro group, carboxyl group, sulfonic acid. A substance containing an acidic group or an electron-accepting group such as a group, or a substance containing a basic or electron-donating group such as a phenyl group, an amide group, an amino group or an ammonium group at a high density in the molecule; Alternatively, a substance in which a salt by an acid / base reaction is formed between these groups and various organic / inorganic compounds is used. Such substances include, for example, nigrosine, derivatives of triphenylmethane dyes typified by sulfates of paraphenylpararose aniline and salts thereof, metal-containing azo dyes, metal complexes of tertiary butyl salicylic acid, alkyl or alkyl Examples thereof include quaternary ammonium salts having an allyl group.

  The carrier particles used in the composite particles include organic particles, metal oxides, metal fluorides, metal sulfides, metal nitrides, metal oxides formed from thermoplastic resins, waxes, crosslinked thermoplastic resins, etc. Inorganic particles formed from carbides, metal sulfates, metal carbonates, etc., particles having a particle size in the range of 1 nm to 10 μm are used, and the particles are preferably substantially spherical.

  The composite particles are preferably coated with the charge control agent on the surface of the carrier particles, but not necessarily coated, for example, the carrier particles and the charge control agent particles are intimately connected to each other to form a composite. It may be.

  According to the charge control experiment of the colored resin particles kneaded with the charge control agent conducted by the present inventors, only the charge control agent present on the surface of the colored resin particles contributes to the charge control of the colored resin particles. It could be confirmed. That is, when the charge control agent is externally added to the colored resin particles and directly mixed with the carrier or the like, the fine particles of the charge control agent generated during the mixing operation adhere to the colored resin particle surface, Compared to colored resin particles obtained by heat-kneading, pulverizing, and classifying the charge control agent together with the thermoplastic resin and colorant at the time of production, the charge control effect is remarkably large even when the amount of charge control agent used is 1/10 or less by weight. It was confirmed to show.

  From this result, it is considered that the charge control of the colored resin particles by the externally added charge control agent is performed through the following processes (a) and (c). That is, (a) the externally added charge control agent particles exist between the colored resin particles and the friction charging member such as a carrier, and a part of the charge control agent particles exchanges charge with the surface of the friction charging member. Both are equal and have oppositely charged charges. (B) Next, the charged charge control agent particles adhere to the surface of the colored resin particles, and the colored resin particles are charged. (C) Fine particles of the charge control agent are generated by the friction operation between the charge control agent and the friction charging member (B) such as a carrier, and the charge control agent fine particles are supplied to the surface of the friction charging member. A constant charge amount is always given to the colored resin particles through the processes (a) to (b).

  However, the problem here is that normal charge control agents are often aggregates of crystals having a primary particle size of 10 μm or more, and when this is added externally, fine particles of the charge control agent are formed. Even if this adheres to the surface of a friction charging member such as a carrier, it is impossible to give the colored resin particles (A) a sufficient amount of charge for charge control, or until a sufficient amount of charge is reached. There are problems such as slow rise of charge amount over time, and deterioration of development characteristics when charge control agent particles having a large particle size adhere to the electrostatic latent image together with the colored resin particles (A).

  The present inventors have made various studies in order to solve the above-described problems, and in order to smoothly charge the colored resin particles according to the above (a) to (c), (1) colored resin particles The charge control agent particles can be smoothly attached to and detached from the surface of the charging friction charging member, and (2) the charge control agent particles for that purpose preferably have a particle size range of several nanometers to 1 μm ultrafine particles. 3) In order to achieve this, it was confirmed that it was essential to use a composite of charge control agent particles and carrier particles.

  That is, normally used charge control agents exist as crystals or aggregates of several μm to several tens of μm, and these can be pulverized or crushed until the particle size ranges from several nm to 1 μm ultrafine particles. very difficult. Also, it is very difficult to supply the obtained ultrafine particles between the colored resin particles and the charging friction charging member in a stable isolated state. However, when carrier particles having a particle size of 1 nm to 10 μm coexist at the time of pulverization or crushing of the charge control agent, the carrier particles not only effectively work as a crushing or crushing aid, but also by crushing or crushing. Since the generated nm to 1 μm particles are adhered to the surface and stabilized, it is possible to prevent re-aggregation of ultrafine charge control agent particles. The composite particles of carrier particles and charge control agent particles obtained as described above can be regarded as charge control agent supply particles to the surface of the frictional charging member such as colored resin particles and carriers, and further supplied from the composite particles. The particle size of the charge control agent applied can be kept between a few nm and 1 μm.

  The ultrafine charge control agent particles in the above-mentioned composite particles can be charged by being transferred to the surface of the carrier particles as they are, or in a state of being depleted from the surface of the carrier particles. And the colored resin particles can be charged.

  Composite particles can be produced by various methods. For example, a method of mixing carrier particles in a step of pulverizing or crushing charge control particles is an efficient production method. In this case, a method of mixing the carrier particles and the charge control particles while applying a strong shearing force at a desired ratio is particularly preferable. The fine powder of charge control agent generated during mixing coats the surface of the carrier particles, but the charge control agent particles forming the coating layer form charge control particles existing outside the particles and a coating layer of external carrier particles. By sliding with the charge control agent particles, the primary particle size is further reduced, and finally, a coating layer of charge control particles having a primary particle size of 1 nm to 1 μm is obtained. Mix carrier particles and charge control particles in a dry state without adding water or organic solvent, in a wet state with water or organic solvent added, or with alumina or zirconia media with a particle size of 0.1 to several mm. Can do.

  Strong shear force to obtain uniform composite particles includes dissolver, high speed mixer, Henschel mixer, pin mill, kneader, twin or triple screw extruder, roll mill, ball mill, attritor, bead mill, mechanical mill, jet mill, etc. It can be obtained by use.

  These devices can be wet or dry depending on the type of carrier particles or a combination of carrier particles and charge control agent particles. When wet, water or an organic solvent is added. A dispersible dispersion medium is used. Moreover, the mixing under the strong shearing force by the above apparatus can be performed in a temperature range of -20 ° C to 200 ° C.

  Disperse a dispersion liquid obtained by dispersing charge control agent or composite particles composed of charge control agent and carrier particles in water or organic solvent on the surface of triboelectric charging member such as colorant particles (A) or carrier, and disperse after dispersion By drying the liquid, fine charge control agent particles or composite particles can be externally added to the surface of the friction charging member such as colored resin particles or carriers. In this method, it is easy to previously adjust the particle size distribution of the charge control agent and carrier particles in the dispersion. A preferable particle diameter range of the externally added fine particles is 1 nm to 1 μm. However, when the charge control agent is dissolved, finer charge control agent particles can be easily externally added.

  The mixing ratio of the carrier particles and the charge control agent is preferably in the range of 10: 0.05 to 0.05: 10 by weight.

  In the above, the friction charging member such as the colorant particles or the carrier is agitated or rotated to form a dynamic state, and the dispersion liquid or the charge control agent solution is sprayed on the colored resin particles (A) or the carrier. This is effective for uniformly externally adding charge control agent particles having a particle size of 1 nm to 1 μm or fine particles of composite particles to the surface of the frictional charging member.

(Function)
As described above, charge control with a particle size of 1 nm to 10 μm is applied to at least one of an electrostatic image developing toner mainly composed of colored resin particles and a friction charging member such as a carrier for rubbing the particles or a mixed system thereof. When composite particles composed of an agent and carrier particles are added, charge control agent particles having a particle size of 1 nm to 1 μm that can be attached and detached adhere to the surface of a frictional charging member such as toner and carrier. The charge control agent particles adhering to the surface of the frictional charging member cause charge transfer to and from the surface of the frictional charging member, and the charge of the opposite polarity is generated in the same amount as that of the frictional charging member. However, when the resin moves to the surface of the colored resin particles by the stirring action in the developing stirrer, the colored resin particles are charged.

  When the colored resin particles are charged by such a mechanism, it is desirable to reduce the size of the charge control agent particles as much as possible. In the case of charge control agent particles having a large particle size as conventionally used, the effect of charge control is exerted. Is significantly limited.

  That is, the composite particles of the carrier particles and the charge control agent act as a supply source of the charge control agent particles having a desirable particle size (1 nm to 1 μm) on the surface of the colored resin particles and the particles of the triboelectric charging member. Even if the composite particles are μm-sized aggregate particles composed of nm-sized carrier particles and charge control agent particles, these particles are crushed by the mixing and stirring action of the colored resin particles and the triboelectric charging member. A fine charge control agent can be stably supplied.

(1) A charge control agent is kneaded and added to the electrostatic image developing toner as in the past, and the rising characteristics of the charge are remarkably higher than those of the electrostatic image developer using the encapsulated electrostatic image developing toner. An improved electrostatic image developer can be obtained.

(2) The charged ultrafine charge control agent can impart a large charge to the colored resin particles with a very small addition amount, so when the conventional charge control agent has been kneaded into the electrostatic image developing toner. A sufficient charge control effect can be obtained with about 1/10 of the amount used.

(3) No contamination of the surface of the photoreceptor or the surface of the frictional charging member due to the released large particle size charge control agent.

(4) Excellent charging characteristics can be realized, for example, the fluctuation of the triboelectric charge amount generated between the electrostatic image developing toner and the carrier is extremely small, and a stable and sufficient charge amount is ensured.

(5) The composite particles of the present invention can be applied not only to external addition to the electrostatic image developing toner surface by a pulverization method but also to suspension polymerization toner, emulsion polymerization aggregation toner, and the like.

(6) The composite particles of the present invention can be added in a dry state, as well as in a wet state if used as a dispersion.

  Hereinafter, modes for carrying out the present invention will be described.

(Example 1)
Polyester resin (glass transition temperature 60 ° C, melting point 140 ° C, acid value 1.0) 100 parts by weight was mixed with 4 parts by weight of phthalocyanine blue and 2 parts by weight of wax (melting point 85 ° C), and then kneaded with a twin screw extruder. . The obtained kneaded material was pulverized by a jet mill and classified to obtain colored resin particles having an average particle diameter of 7 μm. To this particle, 80 parts by weight of spherical acrylic resin having an average particle size of 0.1 μm and 0.3 part by weight of composite particles having an average particle size of 0.3 μ coated with 20 parts by weight of alkali blue are added and mixed with a high speed mixer. A blue toner was obtained. 5 parts by weight of the obtained electrostatic image developing toner and 95 parts by weight of ferrite carrier having an average particle diameter of 50 μm were mixed for 3 minutes with a paint conditioner to prepare a two-component developer, and the toner charge amount was measured by the blow-off method. , + 40μC / g charge amount was obtained, and the rate of increase in charge amount after mixing was 10% or less, and it was confirmed that an electrostatic image developing toner with a stable charge characteristic was obtained with a quick rise in charge. It was.

  2 parts by weight of aminosilane-treated silica particles were added to 100 parts by weight of the blue toner and mixed with a mixer to prepare a positively charged one-component developer, and a standard pattern with a printing rate of 5% was printed with a laser printer. However, a clear image with an image density of 1.2 and a background density of 0.06 was obtained.

  Using the toner externally added with aminosilane-treated silica, the fluctuation rate of the electrostatic image developing toner charge amount when 50,000 prints are superimposed while replenishing the electrostatic image developing toner is 10% or less. There was almost no decrease in density, and the soil density did not exceed 0.08.

(Example 2)
Polyester resin (glass transition temperature 60 ° C., melting point 140 ° C., acid value 1.0) 100 parts by weight and 4 parts by weight of phthalocyanine blue were mixed and then kneaded by a twin screw extruder. The obtained kneaded material was pulverized by a jet mill and classified to obtain colored resin particles having an average particle diameter of 7 μm. A heptane dispersion of composite particles having an average particle diameter of 0.25 μm, in which 50 parts by weight of alumina particles having an average particle diameter of 0.02 μm and 50 parts by weight of alkali blue are mixed while stirring 100 parts by weight of the particles with a high speed mixer (particle concentration 20 %) 1.5 parts by weight were sprayed and dried to obtain a positively charged blue electrostatic image developing toner.

  5 parts by weight of the dry powder of the obtained blue electrostatic image developing toner and 95 parts by weight of a ferrite carrier having an average particle diameter of 50 μm are mixed for 3 minutes with a paint conditioner to prepare a two-component developer, and electrostatic image development is performed by a blow-off method. When the toner charge amount was measured, a toner charge amount of +45 μC / g was obtained. Thereafter, the rate of increase of the charge amount when mixed for up to 30 minutes was 10% or less, and it was confirmed that an electrostatic image developing toner having a rapid charge start-up and stable charge characteristics was produced.

  100 parts by weight of the blue electrostatic image developing toner, 2 parts by weight of aminosilane-treated silica particles are added and mixed with a mixer to prepare a positively charged one-component developer, and a standard pattern with a printing rate of 5% is obtained with a laser printer. As a result of printing, a clear image with an image density of 1.2 and a background smudge density of 0.06 was obtained. The fluctuation rate of the electrostatic image development toner charge amount when printing over 100,000 sheets while replenishing electrostatic image development toner is 10% or less, there is almost no decrease in image density, and the background density is also low. Never exceeded 0.08.

(Example 3)
Example 2 Alkali blue (positive charge control agent) Composite particles formed by coating fine particles on the surface of alumina fine particles, tertiary butylsalicylic acid zinc complex (negative charge type charge control agent), fine particles treated with hexamethylsilazane A two-component developer was prepared in the same manner as in Example 2 except that the composite particles formed by coating silica particles (primary particle size 8 nm) were used. The charge amount of the electrostatic image developing toner was measured to be -50μC / g, and when the mixing was continued until 30 minutes, the increase in the charge amount was 10% or less, and the rise of the charge amount was quick. It was confirmed that a stable negatively chargeable electrostatic image developing toner was formed.

    Two parts by weight of hexamethylsilazane-treated silica particles are added to 100 parts by weight of the blue electrostatic image developing toner and mixed with a mixer to produce a positively charged one-component developer. A standard with a printing rate of 5% using a laser printer When the pattern was printed, a clear image with an image density of 1.2 and a background density of 0.06 was obtained. The fluctuation rate of the electrostatic image developing toner charge amount when printing over 100,000 sheets while replenishing the electrostatic image developing toner is 10% or less, almost no decrease in image density is observed, and the background stain density is also low. Never exceeded 0.08.

(Comparative Example 1)
After mixing 100 parts by weight of polyester resin (acid value 0, glass transition temperature 60 ° C, melting point 140 ° C, acid value 1.0) with 4 parts by weight phthalocyanine blue, 2 parts by weight wax (melting point 85 ° C), and 1.0 part by weight alkali blue The mixture was kneaded with a twin screw extruder. The obtained kneaded material was finely pulverized by a jet mill and classified to obtain a blue electrostatic image developing toner having an average particle diameter of 7 μm. 5 parts by weight of the obtained particles and 95 parts by weight of a ferrite carrier having an average particle diameter of 50 μm were mixed with a paint conditioner for 3 minutes to prepare a two-component developer, and the charge amount was measured by a blow-off method. A toner charge amount was obtained. Thereafter, when stirring was continued for 30 minutes, the charge amount gradually increased, and the increase rate reached 20% or more.

  2 parts by weight of aminosilane-treated silica particles are added to 100 parts by weight of the blue electrostatic image developing toner and mixed with a mixer to prepare a positively charged one-component developer. A standard pattern with a printing rate of 5% is prepared with a laser printer. When the image was printed, a clear image with an image density of 1.2 and a background density of 0.06 was obtained. When 3000 sheets were printed with the electrostatic image developing toner replenished, the electrostatic image developing toner charge amount fluctuated. The rate exceeded 30% and the image density dropped to 0.8. In addition, the background density of the developed image also increased to 0.10.

(Comparative Example 2)
The composite particle of the tertiary butyl salicylic acid zinc complex of Example 3 (negatively charged type charge control agent) and hexamethylsilazane-treated silica particles is used as the tertiary butyl salicylic acid alone, and the external electrostatic image development using only the charge control agent is used. A two-component developer was prepared in the same manner as in Example 2 except that the toner was prepared.

  5 parts by weight of the obtained particles and 95 parts by weight of a ferrite carrier having an average particle diameter of 50 μm were mixed with a paint conditioner for 3 minutes to prepare a two-component developer, and the charge amount was measured by the blow-off method. An electrostatic image developing toner charge amount was obtained. Thereafter, when stirring was continued for 30 minutes, the charge amount gradually increased, and the increase rate reached 40% or more.

  Add 100 parts by weight of the above blue electrostatic image developing toner to 2 parts by weight of hexamethylsilazane-treated silica particles and mix with a mixer to produce a positively charged one-component developer. When the pattern was printed, a clear blue image with an image density of 1.2 and a background smudge density of 0.06 was obtained. However, the image density declined when 2000 prints were overlaid while supplying electrostatic image developing toner. It was 0.3, and the soil density increased to 0.11.

Example 4
80 parts by weight of styrene monomer, 20 parts by weight of butyl methacrylate monomer, 5 parts by weight of carbon black, 2 parts by weight of polyethylene wax (average particle size 1.0 μm, melting point 100 ° C.) and 1 part by weight of a polymerization initiator are mixed in water together with an emulsifier. Then, suspension polymerization was performed to obtain black particles having an average particle diameter of 6.5 μm. The resulting black particles are washed with water to remove emulsifiers, etc., and then added to an aqueous dispersion to obtain an average particle diameter of a metal-containing azo dye (metal: iron, negatively charged charge control agent) and an ester wax (melting point: 75 ° C.). 0.5 parts by weight of a 20% aqueous dispersion of 300 nm composite particles (metal-containing azo dye: wax mixing ratio 70:30) was added and mixed with stirring. The obtained mixed dispersion was dried and crushed after removing water with a filter press or the like to obtain a black electrostatic image developing toner.

  5 parts by weight of the dry powder of the obtained black electrostatic image developing toner and 95 parts by weight of ferrite carrier having an average particle diameter of 50 μm are mixed for 3 minutes with a paint conditioner to prepare a two-component developer, and electrostatic image development is performed by the blow-off method. When the toner charge amount was measured, a negatively chargeable electrostatic image developing toner charge amount of -50 μC / g was obtained. Thereafter, when the two-component developer was mixed for up to 30 minutes, the rate of increase in charge amount was 5% or less, confirming that an electrostatic image developing toner having a quick charge rise and stable charge characteristics was produced. .

  Add 2 parts by weight of hexamethylsilazane-treated silica particles to 100 parts by weight of the above black electrostatic image developing toner and mix with a mixer to prepare a negatively charged one-component developer. When the pattern was printed, a clear black image with an image density of 1.5 and background density of 0.07 was obtained. The fluctuation rate of the electrostatic image development toner charge amount when overlaying 20,000 prints while replenishing the electrostatic image development toner is 10% or less. Never exceeded 0.08.

(Example 5)
Styrene / butyl methacrylate / acrylic acid (weight ratio 85: 14: 1) copolymer emulsion (solid content 30 wt%, particle size 100 nm, glass transition point 60 ° C.) 300 parts by weight ion-exchanged water 2000 parts by weight 5 parts by weight of carbon black and 10 parts by weight of polyethylene wax (melting point 80 ° C., particle size 3000 nm) were added and a dispersion was obtained through a bead mill. While stirring the resulting dispersion, 150 parts by weight of a 40 wt% calcium chloride aqueous solution was added dropwise to agglomerate the dispersed particles. The dispersion temperature was set to 90 ° C. and the mixture was further heated and stirred for 5 hours to obtain a black particle having an average particle size of 8.0 μm. Particles were obtained. The black electrostatic image developing toner dispersion was washed while adding new water, and then a composite particle having an average particle size of 120 nm composed of a zinc complex of tertiary butylsalicylic acid and spherical silica fine powder (average particle size of 100 nm) ( 0.5 part by weight of a 20% aqueous dispersion of a tertiary butyl salicylic acid: silica mixing ratio 20:80) was added and mixed with stirring. Subsequently, this mixed liquid was subjected to filter press, and the obtained press cake was kept in a vacuum dryer at 60 ° C. for 10 hours, dried, and then crushed to obtain black particles.

  The resulting black electrostatic image developing toner 5 parts by weight of dry powder and 95 parts by weight of ferrite carrier having an average particle size of 50 μm are mixed with a paint conditioner to prepare a two-component developer, and electrostatic image developing toner is charged by the blow-off method. When the amount was measured, the initial charge amount at the mixing time of 2 minutes was −50 μC / g, and the increase in charge amount when the mixing time was increased to 30 minutes was 10% or less.

  Next, two-component development in which 5 parts by weight of an electrostatic image developing toner obtained by externally adding 1.0% by weight of hexamethyldisilazane-treated silica powder to 100 parts by weight of the black electrostatic image developing toner is mixed with 95 parts by weight of a spherical ferrite carrier. When an agent was prepared and a standard pattern was printed with a laser printer at a printing rate of 5%, a clear black image with an image density of 1.5 A and a background stain density of 0.06 was obtained. The fluctuation rate of the electrostatic image development toner charge amount when overlaying 20,000 prints while replenishing the electrostatic image development toner is 10% or less. Never exceeded 0.08.

Claims (8)

  (A) a particulate electrostatic image developing toner mainly composed of thermoplastic colored resin particles, or (a) a particulate electrostatic image developing toner mainly composed of thermoplastic colored resin particles; An electrostatic image developer comprising a particulate triboelectric charging member for frictionally charging particles of the electrostatic image developing toner, (c) a composite comprising carrier particles having a particle size range of 1 nm to 10 μm and a charge control agent And an electrostatic image developer to which particles are externally added.   (A) a static electrostatic image developing toner composed mainly of colored thermoplastic resin particles; and (b) a particulate frictional charging member for frictionally charging the electrostatic image developing toner particles. In the electrostatic image developer, (c) composite particles composed of carrier particles having a particle size range of 1 nm to 10 μm and a charge control agent are provided on at least one surface of the electrostatic image developing toner particles and the frictional charging member. An electrostatic image developer which is externally added.   3. The electrostatic image developer according to claim 1, wherein the composite particles (c) are obtained by attaching or coating a charge control agent on the surface of carrier particles.   The electrostatic image developer according to any one of claims 1 to 3, wherein the carrier particles constituting the composite particles of (c) are substantially spherical.   (C) The composite particles (c) are at least partially coated by friction with at least one surface of the electrostatic image developing toner (a) and the friction charging member (b). The electrostatic image developer according to claim 1, wherein the developer is an electrostatic image developer.   6. The electrostatic image developer according to claim 1, wherein the mixing ratio of the carrier particles and the charge control agent is in the range of 10: 0.05 to 0.05: 10 by weight. (A) Particulate electrostatic image developing toner mainly composed of thermoplastic colored resin particles, or (a) Particulate electrostatic image developing toner mainly composed of thermoplastic colored resin particles; In a method for producing an electrostatic image developer comprising a particulate frictional charging member for frictionally charging particles of the electrostatic image developing toner,
(C) a dispersion step of dissolving or dispersing the composite particles in a component constituting at least one of the (a) electrostatic image developing toner and (b) the frictional charging member;
A spraying step of spraying (b) or (b) a solution or dispersion in which the composite particles are dissolved or dispersed;
And a step of drying the liquid sprayed in the spraying step. (B) adding a charge control agent or composite particles composed of carrier particles and a charge control agent to the dispersion of thermoplastic colored resin particles obtained by the polymerization method and mixing them;
And a step of removing the dispersion medium from the obtained dispersion and drying it.