JP3718684B2 - Method for producing toner for electrophotography - Google Patents

Description

【００７３】
また、実施例９〜１４、比較例３、４の現像剤を用いて市販の電子写真複写機（ミノルタカメラ社製、ＥＰ５４００）を用いて１万枚の画出しを行い、初期と１万枚複写後の帯電量とかさ比重（流動性）を調べた。結果を表２に示した。
【００７４】
【表２】

【００７５】
【発明の効果】
本発明の樹脂粒子は、表面上に微粒子が均一に固着されている。
上記樹脂粒子を適用したトナーは、長時間にわたり初期の流動性、帯電性を保持し、高速複写機等の高ストレス条件下にも安定している一方、初期の帯電の立ち上がり特性にも優れている。
【図面の簡単な説明】
【図１】 本発明の樹脂粒子を得るための表面改質装置の一例の概略図である。
【図２】 本発明の樹脂粒子を得るための表面改質装置の撹拌機の概略構成図である。
【図３】 本発明の樹脂粒子を得るための表面改質装置の回転体と固定体の概略図である。
【図４】 本発明の樹脂粒子を得るための表面改質装置の撹拌槽の概略図である。
【図５】 本発明の樹脂粒子を得るための表面改質装置の撹拌槽の概略図である。
【図６】 本発明の樹脂粒子を得るための表面改質装置の撹拌槽の概略図である。
【符号の説明】
１：撹拌機、２：回転軸、３：底板、４：ケーシング、５：開口部、６：開口部、７：撹拌槽、８：底部、８ａ：液溜め、ａ：回転体、ｂ：回転軸、ｄ：最短間隙クリアランス[0001]
[Industrial application fields]
The present invention relates to an electrophotographic toner.Manufacturing methodAbout.
[0002]
[Prior art]
It is well known that the fluidity of toner depends on the coefficient of friction between toner particles and the uniformity of charging on the surface of the toner particles. Conventionally, in order to improve the fluidity of the toner, about 2% of inorganic fine particles such as silica, alumina and titanium oxide are added as post-treatment agents to the toner base particles to reduce the friction coefficient between the toner particles. However, in this method, the post-treatment agent is embedded in the toner particles during mixing and stirring with the carrier, and the fluidity and toner chargeability are greatly changed. Further, the post-treatment agent is spent on the carrier and the like, and the fluidity is also lowered. However, if the post-treatment agent is reduced, the fluidity is lowered and the image quality becomes very poor. Therefore, there is a demand for a toner that can obtain good fluidity with a small amount of post-treatment agent.
[0003]
In order to reduce the post-treatment agent that is inorganic fine particles, a method of fixing fine particles to the toner surface under dry conditions is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-90176.
[0004]
[Problems of the prior art]
When the fine particles are fixed under dry conditions such as those disclosed in the above publication, a lot of cost is required, but it is difficult to fix them uniformly. In addition, in the case of producing a toner by a wet production method that is particularly useful when producing a toner having a small particle diameter, if a surface modification is performed by a conventional dry method, a drying step is required in the middle, and both time and cost are reduced. There is a problem that it takes.
[0005]
Japanese Patent Application Laid-Open No. 63-10667 describes a technique for performing surface modification in a wet process, but it is necessary to perform the treatment at a temperature equal to or higher than the glass transition point of the constituent resin. The difference is that no processing is required.
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances. That is, the present invention performs wet surface modification to uniformly fix fine particles on the surface of resin particles.PowerChild photo tonerManufacturing methodThe purpose is to provide.
[0007]
[Means for Solving the Problems]
That is, the present invention provides fine particles on the surface of the resin base particles.In the method for producing a fixed electrophotographic toner,In a solvent containing a solvent that swells resin base particles without dissolving themIn the resin mother particles with fine particles attached to the surfaceApply high shear force to fix fine particles on the surface of the resin base particles.RuIt is characterized byMethod for producing toner for electrophotographyAbout.
[0008]
In this specification, the resin base particles are resin particles before surface modification, and surface modification is performed to fix fine particles on the surface.TreeFat particles(For example, toner for electrophotography)Get.
[0009]
The resin component constituting the resin mother particles of the present invention is not particularly limited, but it is preferable to use a resin having a glass transition temperature (Tg) of 20 ° C to 100 ° C. Specifically, thermoplastic resins such as styrene resins, (meth) acrylic resins, olefin resins, polyester resins, amide resins, carbonate resins, polyether resins, polysulfone resins, or epoxy resins Resin particles made of a thermosetting resin such as resin, urea-based resin, urethane-based resin, and the like, and copolymers or polymer blends thereof are preferably used. A resin having a glass transition temperature of less than 20 ° C. may cause aggregation at room temperature and is difficult to handle. Further, there is a problem that a resin exceeding 100 ° C. is hardly swelled and fine particles are hardly fixed on the surface of the mother particle.
[0010]
The resin base particles of the present invention may be produced by appropriately selecting from conventionally known methods according to the resin component and the desired particle size or shape. For example, wet granulation methods such as suspension polymerization method, seed polymerization method, emulsion polymerization method, emulsion dispersion granulation method, and dry production methods such as spray granulation method and pulverization method can be raised. The wet granulation method is most desirable in terms of obtaining a high yield. As a method for attaching the fine particles to the surface of the mother particle, a wet method is most desirable from the viewpoint of uniformity of adhesion. However, the present invention is not limited to this, and it may be attached by any conventionally known method such as a method of mixing and stirring mother particles and fine particles in a dry process.
[0011]
Applying a high shear force to the particles (ordered mixture) with the fine particles attached to the resin mother particle surface in a solution containing a solvent that swells the resin that constitutes the mother particles, the fine particles adhere to the mother particle surface. Let The stirring for applying the shearing force in the surface modification method of the present invention is a high shearing force stirrer that can efficiently apply the shearing force to the fine particles by a wet method and can uniformly fix the fine particles to the resin fine particles. For example, a conventionally used one such as a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) or an ultradisperser (manufactured by LK-41 Yamato Kagaku Co., Ltd.) may be used.
[0012]
In the present invention, the solvent that swells the resin constituting the resin mother particles varies depending on the type of resin as a raw material, but may be any solvent that swells without dissolving the resin, such as methyl alcohol, ethyl alcohol, Preferred are n-propyl alcohol, isopropyl alcohol, ethylene glycol, diethylene glycol, acetone, methyl ethyl ketone, tetrahydrofuran, 1,4-dioxane, acetonitrile, formamide, acetic acid, pyridine and the like, and particularly a mixture of these organic solvents and water is preferably used. It is done. The concentration of the aqueous solution may be appropriately selected depending on the type of monomer of the resin, the molecular weight, and the like. By swelling the mother particles with these solvents, the fine particles on the surface of the mother particles can be reliably fixed even if the surface modification is performed in the vicinity of Tg.
[0013]
In the present invention, the fine particles used for the surface modification of the resin base particles may be inorganic fine particles such as silica, alumina and titanium, and organic fine particles such as polystyrene, polyester and PMMA, and may be appropriately selected according to the purpose. Any organic fine particles may be used as long as they do not dissolve in the organic solvent and can be dispersed.
[0014]
The relationship between the resin mother particles and the fine particles is that the particle diameter of the mother particles is D_A, D_BThen, the relationship between the two is 5 ≦ D_A/ D_BThose satisfying ≦ 10000 are preferred. D_BD for_AIf the ratio exceeds 10000, the effect of surface modification cannot be obtained. On the other hand, when the number is less than 5, fine particles are not uniformly deposited on the surface of the mother particle.
[0015]
The amount of fine particles used for the surface modification may be appropriately selected depending on the purpose of the surface modification within the range of 0.1 to 30% by weight, preferably 1 to 10% by weight, based on the resin base particles. If it exceeds 30% by weight, a large number of fine particles that do not adsorb to the resin base particles and are irrelevant to the surface modification are generated.
[0016]
Since the resin particles of the present invention are obtained by wet-modifying a mixture in which fine particles are fixed on the surface of the resin mother particles, the resin particles are wet using resin mother particles produced by a wet granulation method. In the case where the ordered mixture is formed, it can be processed in the wet process consistently without drying in the middle of the process, and the overall manufacturing process can be shortened and the cost can be reduced.
[0017]
As a method for forming an ordered mixture, for example, there is a method in which fine particles are dispersed in a dispersion liquid in which mother particles are dispersed to cause uniform hetero (heterogeneous) aggregation of both. In order to facilitate the dispersion of the fine particles, it is preferable to mix and stir a dispersion of fine particles in which the fine particles are dispersed in the same solvent as the dispersion of the mother particles. Furthermore, if a solvent that swells without dissolving the resin that constitutes the mother particles is used as a dispersion medium for dispersing the mother particles, after the fine particles are deposited on the surface of the resin mother particles, it is continuously increased in the same solvent. The surface modification of the mother particles can be performed by applying a shearing force, and the manufacturing process can be further shortened and the cost can be reduced.
[0018]
In order to heteroaggregate the mother particles and the fine particles, it is preferable to add an electrolyte having an aggregating effect to the solvent. The electrolyte is not particularly limited as long as it is an electrolyte such as aluminum sulfate or a metal salicylic acid complex, and can be suitably used. The amount of electrolyte added is preferably about 0.1 to 2.0% by weight. Moreover, you may add adhesive agents, such as methylcellulose, auxiliary. In this case, the addition amount should be determined in consideration of the influence on the charging property.
[0019]
The high shear force agitator used preferably used for the wet surface modification of the present invention comprises at least an agitator (1) and an agitation tank (7) as shown in FIG. As shown in FIG. 2, the agitator (1) has a rotating body (a) attached to the tip of a rotating shaft (2) extended from an upper drive motor (not shown). The outer periphery is covered with a casing (4) comprising a fixed body (b) also serving as a rotating shaft and a bottom plate (3) joined to the lower end surface thereof. Then, the liquid is sucked into the casing (4) from the opening (5) provided at the center of the bottom plate (3) by the rotation of the rotating body (a) and provided on the upper wall surface of the fixed body (b). From the opened opening (6), the casing (4) is discharged upward. In the vicinity of the rotating blades inside the casing (4), a high shearing force is applied to the liquid passing therethrough, and the fine particles can be uniformly fixed to the resin base particles. In addition, the shape of the rotating body (a) and the stationary body (b) of the stirrer (1) used in the present invention is not particularly limited, and can be appropriately selected according to the characteristics of the liquid.
[0020]
FIGS. 3A and 3B are diagrams showing the shortest clearance d between the rotating body (a) and the stationary body (b) of the high shearing stirrer. The shearing force (energy) applied to the fine particles in the wet method depends on the relative peripheral speed V and the shortest clearance clearance d in the shortest gap between the rotating body (a) and the fixed body (b). For this reason, in the high shearing stirrer suitably used for the wet surface modification of the present invention, the shortest clearance clearance d is preferably 0.1 to 4.0 mm, more preferably 0.5 mm to 2.0 mm. . Furthermore, the shortest clearance d is the particle size D of the toner base particles._AD / D_AIf it is larger than satisfying the relational expression of ≦ 500, the shear force is not sufficiently applied to the fine particles, which is not preferable. d / D_AIt is most preferred to use an apparatus in the range of 200 to 350.
[0021]
The relative peripheral speed V at the shortest gap between the rotating body (a) and the fixed body (b) is preferably in the range of 10 to 100 m / sec. If it is less than 10 m / sec, the energy applied is insufficient, and if it exceeds 100 m / sec, a problem occurs in the structure of the apparatus. The most preferable relative peripheral speed is in the range of 15 to 25 m / sec.
[0022]
The time during which energy is applied (the number of passes) depends on the flow rate passing through the gap and the size of the stirring tank. If the flow rate is small or the stirring tank is larger than the flow rate, the number of passes is reduced. A decrease in the number of passes is not preferable because uniformity decreases.
[0023]
Assuming that the flow rate passing through the shortest gap is Y (L / min) and the dose of the stirring tank is X (L), the amount of Y with respect to X is given by the following formula:
10 ≦ Y / X ≦ 1000
Especially the formula:
100 ≦ Y / X ≦ 500
Those satisfying these conditions are preferred. Moreover, the capacity of the stirring tank and the shape of the stirring tank affect the non-uniformity of the number of passes.
[0024]
There is no particular limitation on the dimensions of the stirring tank, and the shape of the stirring tank is as shown in FIG. 4 (A) as long as the bottom (8) has an inclination and the central part is deepest. Further, the bottom portion may have a linear inclination, or may have a curved inclination as shown in FIG. 4B, or may be inclined stepwise. . As shown in FIG. 5, the volume of the bottom (8) of the stirring tank (7) has the same depth as the depth from the lower end of the side surface of the stirring tank (7) to the center of the bottom, and the stirring tank When a virtual flat bottom portion having the same cross section as the cross section of the side surface portion is considered while the cross section perpendicular to the axis of this is the same depth, the volume V of the bottom portion (8) of the agitation tank (7) Flat bottom volume V₀It is desirable that the ratio be 0.1 to 0.9 times, more preferably 0.3 to 0.6 times. If it exceeds 0.9 times, when a liquid-liquid dispersion system is formed using the stirring tank (7), the circulation frequency of individual droplets may not be sufficiently uniform, On the other hand, if it is less than 0.1, the droplets may not circulate and may stay in the bottom (8). Furthermore, this stirring layer (7) may have a liquid reservoir (8a) having an inner diameter slightly larger than the outer shape of the stirrer to be used, as shown in FIGS. 6 (A) and 6 (B), for example.
[0025]
In producing the resin particles of the present invention, the surface modification of the resin mother particles is performed at a temperature between a temperature lower than the glass transition temperature of the resin by 50 ° C. and the glass transition temperature, more preferably from 10 to 30 ° C. from the glass transition temperature. Perform at low temperature. Since the temperature is not raised above the glass transition temperature of the resin in the high shear force stirring step, the fine particles are not embedded in the molten mother particles, while the mother particles are swollen, so that the fine particles are firmly Fixed to the surface of the particles.
[0026]
After the surface modification is completed, the final resin particle product is obtained by drying. For drying, any known drying method such as air drying after filtration, vacuum drying, or spray drying may be used.
[0027]
The resin particles of the present invention can be applied to toners used in electrophotographic development and printers, cosmetics, pharmaceuticals, and the like. In the resin particles of the present invention, the fine particles are uniformly fixed on the surface of the resin particles without the fine particles being embedded to the inside of the resin mother particles or remaining in a state of being adsorbed on the surface.
[0028]
The resin particles of the present invention are particularly preferably used for an electrophotographic toner. That is, in the present invention, after the fine particles are uniformly attached onto the resin mother particles containing at least a colorant, the resin mother particles are dispersed in a solvent containing a solvent that swells without dissolving, and a high shear force is applied thereto. Also included is an electrophotographic toner comprising resin particles obtained by uniformly fixing fine particles on the surface of resin base particles.
[0029]
The resin constituting the toner of the present invention is not particularly limited as long as it is widely used as a binder in ordinary toners. For example, styrene resin, (meth) acrylic resin, olefin resin , Thermoplastic resins such as polyester resins, amide resins, carbonate resins, polyether resins, polysulfone resins, or thermosetting resins such as epoxy resins, urea resins, urethane resins, etc. These copolymers and polymer blends are also used. The binder resin used in the present invention includes not only those in a complete polymer state as in a thermoplastic resin, for example, but also those in an oligomer or prepolymer state as in a thermosetting resin. Further, a polymer partially containing a prepolymer, a crosslinking agent, and the like are also included.
[0030]
Recently, a technology capable of copying at a higher speed has been demanded. In the toner used in such a high-speed system, the toner can be fixed on a transfer paper in a short time, and can be separated from the fixing roller. It is necessary to improve. Therefore, when trying to obtain a toner for use in such a high-speed system, as a binder resin, a homopolymer synthesized from a styrene monomer, a (meth) acrylic monomer, a (meth) acrylate monomer, or It is desirable to use a copolymer or a polyester-based resin, and the molecular weight is such that the relationship between the number average molecular weight (Mn), the weight average molecular weight (Mw), and the Z average molecular weight (Mz) is 1,000 ≦ Mn. ≦ 7,000, 40 ≦ Mw / Mn ≦ 70, 200 ≦ Mz / Mn ≦ 500, and the number average molecular weight (Mn) may be 2,000 ≦ Mn ≦ 7,000. desirable. When used as an oilless fixing toner, it is desirable that the glass transition temperature is 55 to 80 ° C., the softening point is 80 to 150 ° C., and further a gelling component of 5 to 20% by weight is contained. Further, in order to improve the vinyl chloride resistance, it is desirable to use a polyester resin, and it is particularly desirable to contain 5 to 20% by weight of a gelling component.
[0031]
In addition, when obtaining a translucent color toner used for OHP or full color, the binder resin is vinyl chloride resistance, translucency as a translucent color toner, and adhesion to an OHP sheet. From this point of view, it is desirable to use a polyester resin. In this case, the glass transition temperature is 55 to 70 ° C., the softening point is 80 to 150 ° C., and the number average molecular weight (Mn) is 1,000 to 15, as the molecular weight. A linear polyester having a molecular weight distribution (Mw / Mn) of 4 or less is desirable. Further, as a binder resin for obtaining a translucent color toner, a linear urethane-modified polyester obtained by reacting a linear polyester resin with diisocyanate is also preferably used. The linear urethane-modified polyester mentioned here is composed of a dicarboxylic acid and a diol, and has a number average molecular weight of 2,000 to 15,000 and an oxidation of 5 or less. A linear urethane-modified polyester resin obtained by reacting 0.3 to 0.95 mol of diisocyanate, and having a glass transition temperature of 40 to 80 ° C. and an oxidation of 5 or less. Ingredients. Furthermore, it is a polymer obtained by copolymerizing and modifying a linear polyester with a styrene, acrylic or aminoacrylic monomer by a method such as graft polymerization or block polymerization, and has the same glass transition temperature, softening point and molecular weight characteristics as above. Those are also preferably used.
[0032]
The colorant contained in the electrophotographic toner of the present invention is not particularly limited, and various known organic and inorganic pigments and dyes can be used. Usually, 1 to 20 parts by weight, more preferably 2 to 10 parts by weight is used with respect to 100 parts by weight of the resin. This is because if the amount is more than 20 parts by weight, the toner fixing property is lowered, and if it is less than 1 part by weight, a desired image density may not be obtained.
[0033]
As fine particles used for the surface modification of the toner base particles, silica, alumina, titanium, polystyrene fine particles, PMMA fine particles and the like having a function as a fluidizing agent are preferable. By fixing the fluidizing agent on the base particles, the fluidity required for the toner can be imparted, and suitable fluidity and charging stability can be obtained. In addition, fine particles that function alone or as a plurality of magnetic particles, charge control agents, anti-offset agents, cleaning aids, and the like may be selected and adhered and fixed according to the purpose. In this case, a conventional dry adhesion method can be applied to the charge control agent or the like.
[0034]
The electrophotographic toner of the present invention is preferably post-treated by externally adding inorganic fine particles such as silica, titanium dioxide, alumina, etc., in order to impart long-term fluidity and long-term charge stability. Particularly in this case, it is preferable that 60% or more of the surface area of the toner base particles is coated with inorganic fine particles such as silica. Since the friction coefficient between the inorganic fine particles is much lower than the friction coefficient between the resin particles and the inorganic fine particles, the fluidity can be increased by adding a very small amount of a post-treatment agent. Further, these external additives are not buried even by vigorous mixing and stirring with a carrier, and fluidity and charging stability can be ensured over a long period of time. When the surface coverage is less than 60%, the post-treatment agent enters the concave portion of the toner, the fluidity is lowered, and the chargeability is greatly changed.
[0035]
The post-treatment fine particles are added in an amount of 0.5 parts by weight or less, preferably 0.01 to 0.2 parts by weight based on 100 parts by weight of the toner base particles. If the amount of fine particles for post-processing is too large, the carrier will be spent, resulting in a decrease in charging stability and an effect on the copied image.
[0036]
In the present invention, as described above, when inorganic fine particles that can be used as a fluidizing agent are used for both the surface-modifying fine particles and the post-treatment (externally added) fine particles, even if they are vigorously stirred in the copying machine, It is possible to provide a toner that exhibits excellent fluidity and charging stability over a long period of time without fine particles being embedded in the mother particles. Further, when the amount of the post-treatment fine particles used is about 0.01 to 0.2 parts by weight with respect to 100 parts by weight of the toner base particles, good fluidity can be obtained. It can be reduced from the part. As a result, adhesion of post-treatment fine particles to the carrier can be prevented as much as possible, and charging stability can be achieved.
[0037]
When adding post-treatment fine particles such as silica, the particle size D of the toner base particles_AAnd particle size D of surface modified fine particles_BAnd particle size D of fine particles for post-treatment (external addition)_CPreferably satisfies the following relationship:
5 <D_A/ D_B<10000
5 <D_A/ D_C<10000
0.01 <D_C/ D_B<100
D_A/ D_BIf it is over 10,000, surface modification effect cannot be obtained, and D_A/ D_BIf it is 5 or less, a uniform ordered mixture is not formed, and the surface modification becomes non-uniform. On the other hand, D_A/ D_COr D_C/ D_BIf the value deviates from the above range, the desired fluidity cannot be obtained.
[0038]
In the toner of the present invention, the post-treatment with an external additive may be performed by a normal method. Input and process under normal conditions.
[0039]
Hereinafter, the present invention will be described in more detail by way of examples. Unless otherwise specified, “parts” in this example represent parts by weight.
[0040]
【Example】
Toner production
The toners of Examples 1 to 15 and Comparative Examples 1 to 4 were produced as follows.
[0041]
Example 1
After completely dissolving 100 parts of low molecular weight polyester resin (Mw = 15000, Mn = 6000) in methylene chloride to 20% by weight, 6 parts of carbon black using Eiger Motor Mill (manufactured by Eiger Japan) Then, 4 parts of the charge control agent Bontron E84 (manufactured by Orient Chemical Co., Ltd.) was dispersed in the resin solution.
The polyester resin used in this example was obtained as follows.
2 Liter Four Attach a reflux condenser, nitrogen gas inlet tube, thermometer, and stirrer to the one-necked flask and place it in a mantle heater. 1 : 1 Polyoxypropylene ( 2,2 ) − 2,2 -Screw ( Four -Hydroxyphenyl) propane and terephthalic acid and dibutyltin oxide as a catalyst were charged while introducing nitrogen into the flask. 220 At ℃ 60mmHg The weight average molecular weight is reacted by heating and stirring under reduced pressure of Mw But 15000 , Number average molecular weight Mn But 6000 Of low molecular weight polyester resin.
[0042]
This resin solution was mixed with 1% of Metrose 65SH-50 (manufactured by Shin-Etsu Chemical Co., Ltd.) and 200 ml of an aqueous dispersion containing 1% of sodium lauryl sulfate, and 10 times at room temperature using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). O / W emulsion was obtained by emulsifying and dispersing for 3 minutes at 3800 rpm. Next, it was replaced with a four-blade stirring blade, and methylene chloride was distilled off while stirring at 40 to 45 ° C. for 3 hours to obtain an aqueous suspension of toner particles. After the methylene chloride was completely distilled off, the mixture was allowed to stand for 24 hours, and the solid content accumulated below was taken out by decantation. This operation was further repeated twice, and fine particles of 2 to 3 μm or less were separated and removed together with the supernatant by decantation three times. The toner base particles thus cleaned and classified are washed twice with a cleaning solution in which hydrochloric acid is added to water / methanol (5/5 (w / w)) to adjust the pH to 3, thereby obtaining toner base particles having an average particle diameter of 6 μm. It was.
[0043]
Silica (SiO₂) Ultrafine dispersion of fine particles (R-974: particle size 15 mμ, manufactured by Nippon Aerosil Co., Ltd.) in 3% by weight of toner base particles in 500 ml of methanol, and addition of water equal to methanol to obtain a silica dispersion It was. In this silica dispersion, the toner base particles are mixed so as to have a solid content of 10% by weight, and the toner base particles are dispersed and swollen by ultrasonic dispersion, and then 2 g of aluminum sulfate is added to agglomerate to aggregate the fine particles. An ordered mixture was formed by adsorption onto the surface of the mother particles.
[0044]
Surface modification was performed using the wet surface modification apparatus shown in FIGS. Each condition is as follows:
The shortest gap (clearance) between the rotating body (a) and the fixed body (b): 1.0 mm
Relative peripheral speed at the shortest gap between the rotating body (a) and the stationary body (b): 30 m / sec Flow rate through the shortest gap 100 L / min
Stirring tank capacity 2000-3000ml
Temperature 30 ° C
[0045]
Using the above apparatus, 2 liters of the ordered mixture dispersion was subjected to high shear force stirring treatment for 10 minutes. By this treatment, silica fine particles were fixed on the toner surface. This was spray-dried at a drying temperature of 90 ° C. with Dispercoat DC-08 (manufactured by Nisshin Engineering Co., Ltd.) to obtain the toner of Example 1.
[0046]
Example 2
Alumina (Al₂O_Three) A toner of Example 2 was obtained in the same manner as in Example 1 except that fine particles (RFY-C; particle size 15 mμ: manufactured by Nippon Aerosil Co., Ltd.) were used.
[0047]
Example 3
Titanium dioxide (TiO) instead of silica fine particles₂) A toner of Example 3 was obtained in the same manner as in Example 1 except that fine particles (IT-UD; particle size 17 mμ: manufactured by Idemitsu Kosan Co., Ltd.) were used.
[0048]
Example 4
A toner of Example 4 was obtained in the same manner as in Example 1 except that zinc oxide (ZnO) fine particles (ZnO-200; particle size 10 to 20 mμ: manufactured by Sumitomo Cement Co., Ltd.) were used instead of the silica fine particles.
[0049]
Example 5
A toner of Example 5 was obtained in the same manner as in Example 1 except that polystyrene fine particles (average particle size 0.1 μm, Mw = 2000, Mn = 9000) were used instead of silica fine particles.
[0050]
Example 6
A toner of Example 6 was obtained in the same manner as in Example 1 except that PMMA fine particles (average particle size 0.1 μm, Mw = 20000, Mn = 90000) were used instead of silica fine particles.
[0051]
Example 7
100 parts of low molecular weight polyester, 6 parts of carbon black and 4 parts of charge control agent Bontron E84 were melt-kneaded, cooled, coarsely pulverized with a cutter mill, and further finely pulverized with a jet mill. The finely pulverized toner was classified using an air classifier to obtain toner mother particles having an average particle diameter of 6 μm.
[0052]
Silica fine particles (R-974; particle size 15 mμ: manufactured by Nippon Aerosil Co., Ltd.) were fixed to the mother particles by high shear force in the same manner as in Example 1 and spray dried to obtain the toner of Example 7.
[0053]
Example 8
70 parts of styrene, 30 parts of n-butyl methacrylate, 3 parts of low molecular weight polypropylene wax (Biscol 660P: manufactured by Sanyo Chemical Industries), 8 parts of carbon black (MA-8: manufactured by Mitsubishi Chemical Industries) and 2,2 ′ -A polymerizable composition containing a polymerization initiator was prepared by thoroughly mixing 3 parts of azobis- (2,4-dimethylvaleronitrile) with a sand stirrer. This polymerizable composition was added to a 1.25% by weight polyvinyl alcohol aqueous solution using a TK-auto homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) with stirring at a rotational speed of 6000 rpm, and then three turbine blades were used. The polymerization reaction was carried out at 60 ° C. for 6 hours while stirring at 500 rpm. After completion of the polymerization reaction, the reaction system was cooled and hydrochloric acid was added. Thereafter, classification and washing by decantation were carried out in the same manner as in Example 1, followed by filtration, washing and drying to obtain toner mother particles having an average particle diameter of 6 μm.
[0054]
Silica fine particles (R-974; particle size 15 mμ: manufactured by Nihon Aerosil Co., Ltd.) were fixed to the mother particles by high shearing force in the same manner as in Example 1 and spray dried to obtain the toner of Example 8.
[0055]
Example 9
To the toner obtained in Example 1, 0.1 part of silica fine particle R-974 is added with respect to 100 parts of toner base particles, and mixed by a Henschel mixer at a temperature of 30 ° C. and a rotation speed of 1000 rpm to perform post-treatment. The toner of Example 9 was obtained.
[0056]
Example 10
Al instead of silica fine particles as fine particles for surface modification and post-treatment₂O_ThreeA toner of Example 10 was obtained in the same manner as in Example 9, except that the fine particle RFY-C was used.
[0057]
Example 11
TiO instead of silica fine particles as surface modification and post-treatment fine particles₂A toner of Example 11 was obtained in the same manner as in Example 9, except that the fine particle IT-UD was used.
[0058]
Example 12
The toner obtained in Example 7 was post-treated with silica fine particles R-974 in the same manner as in Example 9 to obtain the toner of Example 12.
[0059]
Example 13
Al instead of silica fine particles as fine particles for surface modification and post-treatment₂O_ThreeA toner of Example 13 was obtained in the same manner as in Example 12 except that the fine particle RFY-C was used.
[0060]
Example 14
TiO instead of silica fine particles as surface modification and post-treatment fine particles₂A toner of Example 14 was obtained in the same manner as Example 12 except that the fine particle IT-UD was used.
[0061]
Example 15
The toner obtained in Example 8 was post-treated with silica fine particles R-974 in the same manner as in Example 9 to obtain the toner of Example 15.
[0062]
Comparative Example 1
After completely dissolving 100 parts of low molecular weight polyester resin (Mw = 15000, Mn = 6000) in methylene chloride so as to be 20% by weight, 6 parts of carbon black, charged using an Eiger motor mill (Eiger Japan) 4 parts of a control agent Bontron E84 (manufactured by Orient Chemical Co., Ltd.) was dispersed in the resin solution.
[0063]
This resin solution was mixed with 1% of Metrose 65SH-50 (manufactured by Shin-Etsu Chemical Co., Ltd.) and 200 ml of an aqueous dispersion containing 1% of sodium lauryl sulfate, and 10 times at room temperature using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). O / W emulsion was obtained by emulsifying and dispersing for 3 minutes at 3800 rpm. Next, the stirring blade was replaced with four blades, and methylene chloride was distilled off while stirring at 40 to 45 ° C. for 3 hours to obtain an aqueous suspension of toner particles. After the methylene chloride was completely distilled off, the mixture was allowed to stand for 24 hours, and the solid content accumulated below was taken out by decantation. This operation was further repeated twice, and fine particles of 2 to 3 μm or less were separated and removed together with the supernatant by decantation three times. The toner base particles thus cleaned and classified are washed twice with a cleaning solution in which hydrochloric acid is added to water / methanol (5/5 (w / w)) to adjust the pH to 3 to obtain toner base particles having an average particle diameter of 6 μm. It was.
[0064]
3% by weight of SiO based on toner base particles₂The fine particle R-974 was mixed with a Henschel mixer for 5 minutes to obtain a toner of Comparative Example 1.
[0065]
Comparative Example 2
100 parts of low molecular weight polyester, 6 parts of carbon black and 4 parts of charge control agent Bontron E84 were melt-kneaded, cooled, coarsely pulverized with a cutter mill, and further finely pulverized with a jet mill. The finely pulverized toner was classified with an air classifier to obtain toner base particles having an average particle diameter of 6 μm.
[0066]
3% by weight of SiO based on toner base particles₂The fine particle R-974 was mixed with a Henschel mixer for 5 minutes to obtain a toner of Comparative Example 2.
[0067]
Comparative Example 3
In the same manner as in Comparative Example 1, toner base particles having an average particle diameter of 6 μm were obtained.₂Fine particles R-974 are mixed with a Henschel mixer for 5 minutes to form SiO on the surface of the toner base particles.₂The toner of Comparative Example 3 was obtained by attaching fine particles.
[0068]
Comparative Example 4
In the same manner as in Comparative Example 2, toner base particles having an average particle diameter of 6 μm were obtained.₂Fine particles R-974 are mixed with a Henschel mixer for 5 minutes to form SiO on the surface of the toner base particles.₂The toner of Comparative Example 4 was obtained by attaching fine particles.
[0069]
Carrier manufacturing
component                                  Parts by weight
・ Polyester resin 100
(Softening point 123 ° C, glass transition temperature 65 ° C AV = 23O, HV = 40)
-Fe-Zn ferrite fine particles 500
(MFP-2: manufactured by TDK)
・ Carbon black 2
(MA-8: manufactured by Mitsubishi Chemical Industries)
[0070]
The above components were sufficiently mixed and pulverized with a Henschel mixer, and then melt-kneaded using an extrusion kneader set at a cylinder portion of 180 ° C. and a cylinder head portion of 170 ° C. The kneaded product was allowed to cool, then coarsely pulverized using a feather mill, further finely pulverized using a jet mill, and then classified using a classifier to obtain a carrier having an average particle diameter of 6 μm.
[0071]
Evaluation
With respect to the carrier thus obtained, the toner obtained in the example was adjusted to have a toner mixing ratio of 5.0%, and developers of Examples 1 to 15 and Comparative Examples 1 to 4 were obtained. The developers of Examples 1 to 8 and Comparative Examples 1 to 4 were mixed and stirred at a rotation speed of 1000 rpm using a ball mount. Changes in chargeability and fluidity after 3 minutes, 90 minutes and 900 minutes were examined. The chargeability was measured using a blow-off powder charge meter (manufactured by Toshiba Chemical Co.). The bulk specific gravity was measured with a JIS plan Z2504 bulk specific gravity meter. The bulk specific gravity represents the fluidity of the developer particles. The larger the bulk specific gravity, the higher the fluidity. The results are shown in Table 1.
[0072]
[Table 1]

[0073]
In addition, using the developers of Examples 9 to 14 and Comparative Examples 3 and 4, a 10,000-sheet image was printed using a commercially available electrophotographic copying machine (Minolta Camera, EP5400). The charge amount and bulk specific gravity (fluidity) after sheet copying were examined. The results are shown in Table 2.
[0074]
[Table 2]

[0075]
【The invention's effect】
In the resin particles of the present invention, fine particles are uniformly fixed on the surface.
The toner to which the resin particles are applied retains the initial fluidity and chargeability for a long time and is stable under high stress conditions such as a high-speed copying machine, but also has excellent initial charge rising characteristics. Yes.
[Brief description of the drawings]
FIG. 1 is a schematic view of an example of a surface modification apparatus for obtaining resin particles of the present invention.
FIG. 2 is a schematic configuration diagram of a stirrer of a surface modification device for obtaining resin particles of the present invention.
FIG. 3 is a schematic view of a rotating body and a fixed body of a surface modifying apparatus for obtaining resin particles of the present invention.
FIG. 4 is a schematic view of a stirring tank of a surface modification device for obtaining resin particles of the present invention.
FIG. 5 is a schematic view of a stirring tank of a surface modification device for obtaining resin particles of the present invention.
FIG. 6 is a schematic view of a stirring tank of a surface modification device for obtaining resin particles of the present invention.
[Explanation of symbols]
1: stirrer, 2: rotating shaft, 3: bottom plate, 4: casing, 5: opening, 6: opening, 7: stirring tank, 8: bottom, 8a: liquid reservoir, a: rotating body, b: rotation Axis, d: shortest clearance clearance

Claims (4)

In a method for producing an electrophotographic toner in which fine particles are fixed on the surface of a resin mother particle, a high shear force is applied to the resin mother particle on which the fine particles are adhered in a solvent containing a solvent that swells without dissolving the resin mother particle. method of manufacturing electrophotographic toner characterized in that Ru is adhered to fine particles on the resin surface of the base particles over. The method for producing an electrophotographic toner according to claim 1, wherein the resin base particles are obtained by a wet granulation method . According to claim 1 or 2 method for producing a toner for electrophotography according the resin base particles is characterized by containing a polyester resin. The fine particles are fixed on the surface of the resin base particles by applying a high shear force under a temperature from a temperature lower by 50 ° C. than a glass transition point of the resin constituting the resin base particles to a glass transition point. The method for producing a toner for electrophotography according to any one of claims 1 to 3 .

Images