JP2000075546A - Production of resin particle and production of electrophotographic toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing resin particles or an electrophotographic toner excellent in productivity by which fine particles can be efficiently and uniformly fixed on the surfaces of particles. SOLUTION: Fine particles are uniformly stuck in a wet state to the surfaces of resin matrix particles or to the surfaces of toner matrix particles and then the fine particles are uniformly fixed on the surfaces of the resin matrix particles or on the surfaces of the toner matrix particles with a colloid mill in which the clearance between a rotor and a stator is 0.3-3.0 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing resin particles having fine particles fixed on the surface and a toner for electrophotography.

[0002]

2. Description of the Related Art In general, inorganic particles such as silica, alumina, and titanium oxide are added to a toner in an amount of several percent as a post-treatment agent in order to sufficiently impart fluidity and chargeability. However, since these inorganic fine particles are buried in toner particles or mixed with carrier particles during mixing and stirring with a carrier, fluidity and chargeability greatly change with repeated use, which is a problem. It is conceivable to reduce the amount of spent post-processing agent to reduce the amount of spent post-processing agent.However, simply reducing the amount of use reduces the amount of inorganic fine particles present on the surface of the toner particles, so that the fluidity and chargeability are immediately reduced. The image quality deteriorates and the image quality deteriorates, and the above problem cannot be solved.

Accordingly, attempts have been made to securely fix a small amount of a post-treatment agent (fine particles) on the surface of toner particles. For example, Japanese Patent Application Laid-Open No. 2-90176 discloses a method of fixing fine particles on the surface of toner particles under dry conditions. However, since the fixing is performed under dry conditions, not only is cost increased, but also it is difficult to fix the fine particles uniformly on the surface of the toner particles. If the fine particles are not uniformly fixed on the surface of the toner particles, the charge amount greatly changes during repeated use, which causes noise such as fog on an image. Also, the toner particles
In the case of manufacturing by a wet manufacturing method useful for manufacturing a small particle size toner, if it is attempted to fix the fine particles on the particle surface under the dry condition as described above, a drying step is required during the manufacturing of the toner, and much time and Not only is it costly, but also many of the toners obtained by the wet process have small diameters and spheres, making it difficult to fix fine particles efficiently and uniformly under dry conditions.

Japanese Patent Application Laid-Open No. 63-10667 discloses a technique for fixing fine particles to the surface of toner particles under wet conditions. However, it is necessary to control the processing temperature to be equal to or higher than the glass transition point of the constituent resin. Therefore, the processing procedure is extremely complicated. Further, Japanese Patent Application Laid-Open No. 6-248663 discloses a technique in which fine particles are fixed to the surface of toner particles under a wet condition. It takes a lot of time to adhere to the surface, and the throughput is low.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing resin particles or electrophotographic toner having excellent productivity, which enables fine particles to be efficiently and uniformly fixed on the particle surface. I do.

[0006]

The present invention is characterized in that the fine particles are uniformly adhered to the surface of the resin base particles by a colloid mill after the fine particles are uniformly adhered to the surface of the resin base particles, and the fine particles are uniformly fixed to the surface of the resin base particles by a colloid mill. The present invention relates to a method for producing particles.

The present invention also provides a method of uniformly adhering fine particles to the surface of toner base particles comprising at least a binder resin and a colorant on a surface of the toner base particles by a colloid mill after uniformly adhering the fine particles to the surface of the toner base particles. The present invention relates to a method for producing a toner for electrophotography.

In the present specification, resin base particles refer to resin particles before surface modification, and in the present invention, fine particles are fixed (surface modified) on the surface to obtain resin particles.
Further, the toner base particles refer to toner particles before surface modification, and in the present invention, fine particles are fixed on the surface thereof.
(Surface modification) to obtain a toner. Further, the surface modification refers to a treatment for modifying the surface properties of the base particles, and in this case, a treatment for fixing the fine particles on the surface of the base particles.

Hereinafter, the method for producing the toner for electrophotography will be described in detail. The method for producing the resin particles is the same as that except that the resin base particles do not contain a toner component such as a colorant which is optionally contained in the toner base particles. This is the same as the method for producing an electrophotographic toner. The present invention does not prevent the resin base particles from containing other components within a range that does not impair the effects of the present invention in the method for producing resin particles. Further, the toner base particles in the following method for producing an electrophotographic toner correspond to the resin base particles in the method for producing resin particles.

In the method of the present invention, the toner base particles comprising at least the binder resin and the colorant are appropriately selected from conventionally known methods in accordance with the binder resin component and the desired particle size or shape. It may be manufactured. For example, suspension polymerization method, seed polymerization method, emulsion polymerization method, wet granulation method such as emulsification dispersion granulation method, spray granulation method, dry manufacturing method such as pulverization method and the like, but uniform spherical particles. In terms of obtaining a high yield, wet granulation is most preferable. In the present invention, the toner base particles are preferably produced by a wet granulation method in order to adhere and fix the fine particles on the surface of the toner base particles in a wet process as described later. After the toner base particles are granulated in a wet process, they can be processed in a wet process without drying, and the fine particles can be adhered and fixed to the surface of the toner base particles. This is because it is possible to reduce the amount of light.

For example, when the toner base particles are produced by the emulsification dispersion granulation method, specifically, at least a binder resin and a colorant are dissolved and dispersed in an organic solvent to obtain a uniform mixed dispersion. The dispersion was mixed with an aqueous solution containing a dispersant, and a mini-colloider (MC-1; manufactured by SMT) was used. K. The dispersion is performed by a dispersing machine such as Mycolloider (manufactured by Tokushu Kika Co., Ltd.), Homo Mixer (made by Tokushu Kika Kogyo Co., Ltd.), Ultra Turrax (made by IKA Co.). The resulting dispersion is heated under reduced pressure if necessary to remove the organic solvent, and after cooling, filtration / washing is repeated to obtain toner base particles. In the present invention, the dispersing machine used in the production process of the toner base particles is not particularly limited, but the impact force generated when the object passes through the clearance between the high-speed rotating rotor and the stator, the shearing force,
Colloid mills utilizing a cavitation effect due to a force such as a compressive force or a frictional force and high-speed rotation, for example, a mini-colloider (MC-1; manufactured by SMT), K. It is preferable to use Mycolloider (manufactured by Tokushu Kika Co., Ltd.) or the like. This is because toner base particles having a sharp particle size distribution can be obtained.

The volume average particle diameter (Da) of the toner base particles is 1
It is desirable that the thickness be controlled to 10 to 10 μm, preferably 3 to 8 μm.

The binder resin constituting the toner base particles is not particularly limited as long as it is a known resin which has been conventionally used as a binder resin constituting a toner, and has a glass transition temperature (Tg) of 20. It is preferable to use a resin having a temperature of from 100C to 100C. Specifically, thermoreversible resins such as styrene-based, (meth) acrylic, olefin-based, polyester-based, amide-based, carbonate-based, polyether-based, and polysulfone-based resins, or epoxy-based, urea-based, and urethane-based resins A thermosetting resin such as a resin, and a resin composed of a copolymer or a polymer blend thereof are preferably used. In the case of a resin having a glass transition temperature of less than 20 ° C., aggregation may occur at room temperature, and handling is difficult. On the other hand, when the temperature exceeds 100 ° C., the inorganic fine particles are hardly fixed.

The coloring agent is not particularly limited, and coloring agents conventionally used in electrophotography can be used, and the following can be exemplified. As the black pigment, carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, ferrite, magnetite and the like can be used. As yellow pigments, yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navels yellow, naphthol yellow S, banza yellow G, banza yellow 10G, benzidine yellow G, benzidine yellow GR, Quinoline yellow lake, permanent yellow NCG, tartrazine lake and the like can be used.

As the red pigment, red lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, induslen brilliant orange RK, benzidine orange G, induslen brilliant orange GK, bengala, cadmium red, red lead, permanent Red 4R, Risor Red,
Pyrazolone red, watching red, lake red C, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake,
Brilliant Carmine 3B, permanent orange GT
R, Vulcan Fast Orange GG, Permanent Red F4RH, Permanent Carmine FB and the like can be used. Blue pigments include navy blue, cobalt blue, alkaline blue lake, Victoria blue lake,
Phthalocyanine blue or the like can be used. In addition, although the addition amount of these coloring agents is not particularly limited,
Usually, 1 to 20 parts by weight with respect to 100 parts by weight of the binder resin,
Preferably, 3 to 15 parts by weight is suitable.

In the method of the present invention, the toner base particles include
Other toner components, for example, a charge control agent, an anti-offset agent, and a magnetic substance may be contained. As the charge control agent, a known charge control agent conventionally used as a charge control agent for toner can be used, and its addition amount is preferably 1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. .

As the offset preventing agent, a known offset preventing agent capable of preventing offset can be used, and its addition amount is preferably 1 to 30 parts by weight based on 100 parts by weight of the binder resin. As the magnetic material, a known magnetic material can be used, and its addition amount is preferably 1 to 50 parts by weight based on 100 parts by weight of the binder resin.

In the method of the present invention, fine particles are uniformly adhered to the surface of the toner base particles as described above in a wet system.
The toner base particles to which the fine particles are uniformly attached are obtained in the mixed system. In the present specification, particles in a state where the fine particles are uniformly attached to the surface of the base particles are referred to as ordered mixture.

As a method of uniformly attaching fine particles to the surface of the toner base particles, that is, a method of forming ordered mixture, for example, the base particles are dispersed in a dispersion liquid in which the fine particles are dispersed, or the base particles are dispersed. The mixed dispersion is obtained by dispersing fine particles in the resulting dispersion, and uniform hetero (heterogeneous) aggregation of the two is caused. Also,
A dispersion in which fine particles and base particles are separately dispersed may be mixed to obtain a mixed dispersion, and hetero-aggregation may be caused. In this case, in order to make the dispersion of the fine particles easier, it is preferable that the dispersion solvent of the fine particles is the same as the dispersion solvent of the base particles.

In any of the above-mentioned methods for forming the ordered mixture, the dispersion solvent for dispersing the base particles is a solvent that swells without dissolving the resin constituting the base particles. Preferably, it is used. As such a solvent, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, ethylene glycol,
Organic solvents such as diethylene glycol, acetone, methyl ethyl ketone, tetrahydrofuran, 1,4-dioxane, acetonitrile, formamide, acetic acid, and pyridine are preferable, and a mixed solvent of these organic solvents and water is particularly preferable. By using such a dispersion solvent, in the case where hydrophobic fine particles are used as the fine particles, the uniform adhesion of the fine particles to the base particles in the mixed dispersion is improved.

In order to cause hetero-aggregation of the base particles and the fine particles, it is preferable to add an electrolyte to the mixed dispersion. As the electrolyte, for example, aluminum sulfate,
Any electrolyte such as calcium chloride, sodium chloride and salicylic acid metal complex can be used without particular limitation. The addition amount of the electrolyte is 0.1 to 2.
It is preferably 0% by weight.

In the mixed dispersion in which the base particles and the fine particles are dispersed, an electrostatic repulsion and a Van der Waals force act between them, and it is generally considered that the electrostatic repulsion is dominant. By using the dispersion solvent and the electrolyte as described above, the thickness of the electric double layer of the base particles and the fine particles is compressed, the electrostatic repulsion of both is weakened, and the van der Waals force becomes dominant. It is considered that hetero-aggregation occurs effectively and toner base particles to which fine particles are uniformly attached can be efficiently obtained in the mixed system.

The fine particles used in the present invention include silica, alumina, titanium oxide, magnesium fluoride, silicon carbide, boron carbide, titanium carbide, zirconium carbide, boron nitride, titanium nitride, zirconium nitride, and the like.
Examples thereof include inorganic fine particles such as magnetite, molybdenum disulfide, aluminum stearate, magnesium stearate, and zinc stearate, and organic fine particles such as polystyrene, polyester, and polymethyl methacrylate, which may be appropriately selected depending on the purpose. Any organic fine particles may be used as long as they do not dissolve in the above-mentioned dispersion solvent and can be dispersed. From the viewpoint of environmental resistance, these fine particles are desirably used after being subjected to a hydrophobic treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil, or the like.

The amount of the fine particles to be added is 0.1 to the base particles.
1 to 30% by weight, preferably 1 to 10% by weight is desirable. If the added amount exceeds 30% by weight, a large number of fine particles that do not adhere to the base particles are generated. Therefore, when the obtained toner is used as a two-component developer, the fine particles are spent on the carrier particles, and the fluidity increases with repeated use. In addition, there is a problem that the chargeability changes greatly. On the other hand, if it is less than 0.1% by weight, the effect of adding fine particles cannot be obtained, and desired fluidity cannot be obtained.

The average primary particle size (Db) of the fine particles is 0.1.
001 to 2 μm, preferably 0.01 to 1 μm.
When the particle size is smaller than 0.001 μm, the fluidity of the obtained toner becomes too high, and it becomes difficult to handle the toner. On the other hand, if it is larger than 2 μm, the desired fluidity cannot be obtained, and the charge amount greatly changes during repeated use, causing noise such as fog on an image.

In a preferred embodiment of the present invention,
The volume average particle diameter Da (μm) of the toner base particles and the average primary particle diameter Db (μm) of the fine particles satisfy the following relational expression: 5 <Da / Db <1,000, preferably 8 <Da / Db <800. Is desirable. The volume average particle diameter (Da) of the toner base particles is the volume average particle diameter of the particles that have not swelled.

When Da / Db is 1,000 or more, it is difficult to obtain the effect of surface modification. On the other hand, when it is 5 or less, it becomes difficult for the fine particles to uniformly adhere to the surface of the base particles, and the effect of the surface modification becomes uneven.

The concentration of the odd mixture in the mixed system is not more than 30% by weight, preferably 5 to 20% by weight. If the content exceeds 30% by weight, uniform fixation of the fine particles to the surface of the base particles may not be achieved during the subsequent fixation treatment. It is desirable that the viscosity of the mixed system at 25 ° C. is 1 to 50 cp, preferably 1 to 30 cp. If it is higher than 50 cp, uniform fixation of the fine particles to the surface of the base particles may not be achieved during the subsequent fixing treatment.

In the present invention, after the fine particles are uniformly adhered to the surface of the toner base particles in the wet manner as described above, the fine particles are uniformly fixed to the surface of the toner base particles by a colloid mill. Specifically, the mixed system containing the odard mixture obtained by uniformly adhering the fine particles to the surface of the toner base particles in a wet method is directly subjected to a fixing treatment using a colloid mill.

In the present invention, a colloid mill is employed as the fixing means. Specifically, a colloid mill that uses the cavitation effect of high-speed rotation, such as the impact, shear, compression, and frictional forces that occur when the workpiece passes through the clearance between the high-speed rotating rotor and stator For example, a mini-colloider (MC-
1: SMT), T.I. K. My Colloider (manufactured by Tokushu Kika Co., Ltd.) is used.

More specifically, for example, a description will be given with reference to a schematic sectional configuration diagram of a mini-colloider (MC-1; manufactured by SMT) shown in FIG. This device comprises a rotor 1 rotating at high speed and a stator 2 fixed. The rotor 1 is connected to a motor 6 by a motor shaft 4, and is rotated by driving the motor 6. The clearance between the rotor 1 and the stator 2 is freely adjustable, and the rotation speed of the rotor is also adjustable. The clearance is adjusted by a known method (not shown), for example, by moving the rotor up and down or moving the stator up and down.

In the apparatus having such a configuration, when the mixing system is supplied from the upper hopper 3 while rotating the rotor 1, when the mixing system passes through the clearance between the rotor 1 and the stator 2, the rotor clearance surface 1 'is formed. And / or a cavitation effect due to a strong impact force, shear force, compression force, friction force, or the like, and high-speed rotation of the rotor from the stator clearance surface 2 ′ arranged to form a clearance in opposition thereto. ,
It is considered that the fine particles in the odd mixture (particles in which the fine particles are uniformly attached to the surface of the base particles) in the mixed system are appropriately fixed to the surface of the base particles. The mixed system after the treatment is discharged from the outlet 5.

Here, a mini-colloider is exemplified and described as an example of the colloid mill, but the present invention is not limited to this. That is, in the present invention, the mixing system passes through the clearance between the rotor and the stator. At this time, a force such as an impact force, a shearing force, a compressive force, a frictional force (hereinafter referred to as an impact force, etc.) is applied from the rotor clearance surface 1 'and / or the stator clearance surface 2' arranged to form a clearance opposed thereto. ), And any type of colloid mill capable of undergoing cavitation can be used. Therefore, the cross-sectional shape of the rotor is not limited to the shape shown in FIG. 1 as well, that is, as long as the rotor clearance surface and / or the stator clearance surface are within a range capable of providing impact force or the like and cavitation action to the mixed system. Various cross-sectional shapes such as a trapezoidal shape, a square shape, and a triangular shape as shown in FIG. 4 may be adopted. In this case, it is preferable that the stator clearance surface is also deformed according to the rotor clearance surface.

The adhesion between the fine particles and the base particles depends on the rotor rotation speed and the clearance conditions, as well as the concentration of the odd mixture in the mixed system and the viscosity of the mixed system to be subjected to the above-mentioned fixing treatment. That is, the rotor rotation speed is too slow or the clearance thickness (m) indicated by oblique lines in FIG.
If the particle size is too large, the fine particles are not uniformly fixed on the surface of the base particles, and even if they are fixed, they are not fixed with an appropriate strength, so that the fine particles are easily released from the toner during repeated use, and the fluidity and chargeability deteriorate. I do. On the other hand, if the rotor rotation speed is too high or the m value is too small, the fine particles are not uniformly fixed on the base particle surface, and even if fixed, the fine particles are likely to be buried in the base particles, and the fluidity and A problem arises in chargeability. For this reason, the rotor rotation speed is generally 3,000 to 8,000 rpm
m, preferably at 5,000 to 8,000 rpm, the m value is 0.3 to 3.0 mm, preferably 1.0 to 2.5 mm
It is desirable to set to. If the thickness (m) of the clearance is too small, there is a possibility that the mixed system after the treatment will not be discharged, which may cause a problem.

The mixed system to be subjected to the above-mentioned fixing treatment is controlled to a temperature equal to or lower than the glass transition temperature of the binder resin constituting the toner base particles, preferably 10 to 50 ° C. lower than the glass transition temperature. Is preferred. That is, if the temperature of the mixed system at the time of the fixing treatment exceeds the glass transition temperature of the binder resin, coalescence of the base particles occurs, and the particle size distribution of the obtained toner becomes broad.

Since the colloid mill having the above structure can be operated continuously, that is, unlike the batch type, the raw material can be continuously supplied, so that the throughput of the method of the present invention is smaller than that of the conventional method. Improve dramatically. Specifically, the processing speed in the fixing step of the method of the present invention can be at least about 50 liters / hour, so that the processing time should be reduced to about 1/10 compared to the conventional fixing method. Can be.

In the case where efficient and uniform fixation of the fine particles to the base particles cannot be achieved by a single fixing treatment, in the present invention, as shown in FIG. The mixing system discharged from the discharge port as shown in FIG. 3 is supplied to a hopper via a pump P and circulated a plurality of times as shown in FIG. be able to. It is desirable to secure a processing time of 0.5 to 5 minutes. Here, the processing time is the time required for the mixed system to pass through the clearance.

The mixed system subjected to the fixing treatment as described above is thereafter subjected to a known drying treatment to obtain a toner in which fine particles are uniformly fixed on the surface of the base particles. As a drying method, any of known drying methods such as air drying after filtration, vacuum drying, spray drying, and freeze drying may be employed.

The toner obtained by the method of the present invention is
The fine particles are efficiently and uniformly fixed to the surface of the base particles. That is, even if the amount of the fine particles used is small, a toner in which the fine particles are efficiently and uniformly fixed on the surface of the base particles can be obtained through the above-described fixing treatment. Further, in the method of the present invention, since the above-mentioned colloid mill is employed as the fixing means, the throughput is remarkably improved. Furthermore, since the toner obtained by the method of the present invention has fine particles uniformly fixed on the surface of the base particles with an appropriate strength, free particles are not generated much even in repeated use, and good fluidity is obtained. And the chargeability can be maintained.

The toner obtained by the method of the present invention can be used in either a one-component developer using no carrier or a two-component developer used with a carrier.
The method of the present invention is described in more detail by the following examples.

[0041]

EXAMPLE 1 Low molecular weight polyester (Mw: 13,700, Mn: 4,20)
(0, Tg: 60 ° C.) in 100 g of toluene, 6 g of phthalocyanine pigment, and VP- as a charge control agent.
434 (manufactured by Hoechst) 1 g, E-84 (manufactured by Orient)
Put 2g into 2l poly bottle and Ultra Turrax (IK
Mixed 30 minutes A Corp.), dispersed uniformly mixed dispersion (eta _A
= 9.6). The obtained mixed dispersion is subjected to PVA PA
-18 (manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed with a dispersion (η _B = 8.8) obtained by dissolving 0.01 g of sodium alkyldiphenyletherdisulfonate in 1000 g of a 3.0% by weight aqueous solution.
The emulsification was performed five times with a mini-colloider (manufactured by SMT, frequency 100 Hz, clearance 1.0 mm) five times (total of about 1 minute). After that, 60 ° C to 65 ° C, 140mmHg to 70m
Toluene was removed under mHg conditions, and after cooling, filtration / water washing was repeated several times to obtain toner mother particles.

Silica fine particles (R-974; average primary particle size 1
2 g of 2 nm (manufactured by Nippon Aerosil Co., Ltd.) was ultrasonically dispersed in 500 cc of methanol, and an equal amount of water was added to methanol to obtain a silica dispersion. 100 g of the toner base particles are mixed with the silica dispersion liquid, and the mixture is ultrasonically dispersed to disperse and swell the toner base particles. Then, 2 g of aluminum sulfate is added to cause aggregation, and the silica fine particles adhere to the surface of the toner base particles. A mixed system containing the ordered mixture thus obtained was obtained.

The mixed system containing the ordered mixture thus obtained was passed through a colloid mill (mini-colloider; manufactured by SMT) as shown in FIG. 1 to perform a surface modification treatment of the toner base particles. It was fixed on the surface of the mother particle. The reforming conditions are shown below. Then, use Dispercoat DC-08 (manufactured by Nisshin Engineering Co., Ltd.)
The toner was obtained by spray drying at ℃. Observation of the toner surface by SEM confirmed that the fine particles were uniformly fixed. Frequency: 134Hz (8,000rpm) Clearance: 1mm Processing time: 1 minute Processing temperature: 25 ° C

Example 2 Instead of silica fine particles, titanium oxide fine particles (IT-UD;
A toner was obtained in the same manner as in Example 1 except that an average primary particle size of 17 nm; manufactured by Idemitsu Kosan Co., Ltd. was used. Observation of the toner surface by SEM confirmed that the fine particles were uniformly fixed.

Comparative Example 1 Low molecular weight polyester (Mw: 13,700, Mn: 4,20)
0, Tg: 60 ° C.)
6 g of phthalocyanine pigment, VP-43 as a charge control agent
4 (manufactured by Hoechst) and 2 g of E-84 (manufactured by Orient) were placed in a 2 l polybin, mixed and dispersed with an Ultra Turrax (manufactured by IKA) for 30 minutes, and uniformly mixed and dispersed (η _A =
9.6) was obtained. The obtained mixed dispersion was subjected to PVA PA-
18 (manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed in a dispersion (η _B = 8.8) prepared by dissolving 0.01 g of sodium alkyldiphenylether disulfonate in 1000 g of a 3.0% by weight aqueous solution. Emulsification was carried out for 10 minutes with a K-auto homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd .; rotation speed: 4,000 rpm). afterwards,
Toluene was removed under the conditions of 60 ° C. to 65 ° C. and 140 mmHg to 70 mmHg, and after cooling, filtration / washing was repeated several times to obtain toner mother particles.

Silica fine particles (R-974; average primary particle size 1)
5 μm, manufactured by Nippon Aerosil Co., Ltd.)
Ultrasonic dispersion was performed in c, and water equivalent to methanol was further added to obtain a silica dispersion. 100 g of the toner base particles are mixed with the silica dispersion liquid, and ultrasonically dispersed to disperse and swell the toner base particles.
Was added to cause aggregation, and silica fine particles were adhered to the surface of the toner base particles to form ordered fracture.

The obtained ordered mixture was placed in T.D.
Using a K-auto homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), the surface of the toner base particles was subjected to a surface modification treatment to fix the silica fine particles on the surface of the toner base particles. The reforming conditions are shown below. Then, it was spray-dried with Dispercoat DC-08 (manufactured by Nisshin Engineering) at 100 ° C. to obtain a toner. Rotation speed: 10,000 rpm Clearance: 1 mm Processing time: 1 minute Processing temperature: 25 ° C

Comparative Example 2 A toner was obtained in the same manner as in Comparative Example 1 except that the surface modification treatment time was changed to 10 minutes. Comparative Example 3 Instead of silica fine particles, titanium oxide fine particles (IT-UD;
A toner was obtained in the same manner as in Comparative Example 1 except that the particle size was 17 nm (manufactured by Idemitsu Kosan Co., Ltd.). Comparative Example 4 Instead of silica fine particles, titanium oxide fine particles (IT-UD;
A toner was obtained in the same manner as in Comparative Example 2 except that the particle size was 17 nm (manufactured by Idemitsu Kosan Co., Ltd.).

(Evaluation) The toner obtained as described above was evaluated for the amount of charge and the amount of inorganic fine particles fixed according to the following evaluation methods.

The developer was obtained by mixing the charge amount toner and the carrier described below so that the toner mixing ratio was 5.0% by weight. The obtained developer 3
0 g was placed in a 50 ml polybin, and rotated at 120 rpm for 5 minutes and 60 minutes, and then the charge amount was measured by the following electric field separation method.

Electric field separation method: 1 g of developer is set on a magnet roller, and a counter electrode whose weight is measured in advance is set. A bias of 1 kV is applied to the same polarity as the toner polarity, and the magnet roll is rotated at 500 rpm for 1 minute. After completion, the voltage between the electrodes and the weight of the counter electrode were measured, and the amount of toner (g) (M) adhering to the electrodes and the capacity of the capacitor (here, the product of 1 (μF) and the voltage (V) between the electrodes) were measured. From (Q), the charge amount of the toner; Q / M (μc / g) is determined.

Inorganic fine particle fixed amount 1 g of toner is weighed, placed in a crucible, and heated in a high-temperature roasting furnace for 800 g.
The mixture was roasted at 3 ° C. for 3 hours to burn organic substances. After cooling to room temperature, the weight of the remaining inorganic fine particles was measured, and the amount of the fixed inorganic fine particles was determined in% by weight.

Table 1 shows the evaluation results.

[Table 1]

From Table 1, it is clear that the toners of Examples 1 and 2 have a stable change in the amount of charge, a high amount of adhered fine particles, and a high processing ability in the production process thereof. It became clear that the toners of Comparative Examples 1 and 3 had almost no fine particles fixed. Therefore, it is considered that the charge amount was low and the transition was unstable. Comparative Example 2
It is clear that the toners of Nos. 4 and 4 have an unstable change in the amount of charge, and have a low processing capacity in the production process thereof. Further, the amount of adhered fine particles was lower than those of the toners of Examples 1 and 2.

(Production of carrier) 80 parts by weight of a styrene-acrylic copolymer (polymerization molar ratio 1.5: 7: 1: 0.5) composed of styrene, methyl methacrylate, 2-hydroxyethyl acrylate, and methacrylic acid 20 parts by weight of a butylated melamine resin was diluted with toluene to prepare a styrene acrylic resin solution having a solid ratio of 2%. Fired ferrite powder as core material (F-300; average particle size: 50 μm, bulk density:
The core material was coated with the above styrene acrylic resin solution by a spiral coater (manufactured by Okada Seiko Co., Ltd.) using 2.53 g / cm ³ (manufactured by Powder Tech) and dried. The obtained carrier was calcined by leaving it at 140 ° C. for 2 hours in a hot air circulation oven. After cooling, the ferrite powder bulk is
Pulverization was performed using a sieve with a screen mesh of μm and 90 μm to obtain a resin-coated ferrite powder. The above application, baking, and crushing of the ferrite powder were further repeated three times to obtain a resin-coated carrier. The obtained carrier had an average particle size of 52 μm and an electric resistance of about 3 × 10 ¹⁰ Ωcm.

[0056]

According to the method of the present invention, resin particles having fine particles fixed efficiently and uniformly can be produced with high productivity. Further, according to the method of the present invention, a toner having good fluidity and chargeability, in which fine particles are efficiently and uniformly fixed, can be produced with high productivity.

[Brief description of the drawings]

FIG. 1 shows a schematic cross-sectional configuration diagram of an example of a colloid mill used in the method of the present invention.

FIG. 2 shows a conceptual diagram when a plurality of the colloid mills of FIG. 1 are connected in series.

FIG. 3 shows a conceptual diagram in the case where a mixing system is circulated using the colloid mill of FIG.

FIG. 4 shows a schematic sectional view of an example of a rotor.

[Explanation of symbols]

1: rotor, 1 ': rotor clearance surface, 2: stator, 2': stator clearance surface, 3: hopper, 4: motor shaft, 5: outlet, 6: motor.

Claims (4)

[Claims] 1. A method for producing resin particles, wherein fine particles are uniformly adhered to the surface of the resin base particles in a wet manner, and then the fine particles are uniformly fixed to the surface of the resin base particles by a colloid mill. 2. The method according to claim 1, wherein the fine particles are uniformly adhered on the surface of the toner base particles comprising at least a binder resin and a colorant in a wet process, and then the fine particles are uniformly fixed on the surface of the toner base particles by a colloid mill. A method for producing an electrophotographic toner. 3. The method for producing an electrophotographic toner according to claim 2, wherein the clearance between the rotor and the stator in the colloid mill is 0.3 to 3.0 mm. 4. The volume average particle diameter Da (μ) of the toner base particles.
4. The electrophotographic toner according to claim 2, wherein m) and the average primary particle diameter Db (μm) of the fine particles satisfy the following relational expression: 5 <Da / Db <1,000. Production method.