JP2001100458A - Method for manufacturing resin particle and method for manufacturing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing resin particles or toners which is capable of rapidly, efficiently and arbitrarily controlling particle shapes from indeterminate forms to nearly round shapes, immobilizing particulates uniformly on particle surfaces with adequate strength. SOLUTION: This method for manufacturing the resin particles or the toners consists in imparting ultrasonic energy, in the presence of the particulates, to a dispersion prepared by dispersing the particles consisting of at least a resin into a resin insoluble medium.

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 and a method for producing a toner for developing an electric latent image in electrophotography or electrostatic recording.

[0002]

2. Description of the Related Art In recent years, high image quality has been demanded for copiers and printers, and improvements such as reduction in diameter and spheroidization of toner have been made to satisfy such demands. By reducing the diameter of the toner, the resolution of the image is increased, and by making it spherical, the transferability and durability are excellent.

A conventional method for producing a toner used in electrophotography or the like is to add a colorant, a charge control agent, a grinding aid, a release agent, and the like to a thermoplastic resin, knead the mixture, and then solidify the kneaded product. The mainstream is a so-called pulverization method, in which a pulverized material is obtained by pulverizing and then classifying to obtain a toner product. Further, as a method of spheroidizing the toner particles, a method of producing a spherical toner by applying a mechanical impact force to a pulverized material and a method of producing a spherical toner by applying heat to the pulverized material are known.

However, in the method of applying a mechanical impact force, an irregular shape is generated by pulverization, and energy is continuously applied for a long time to make a sphere close to a perfect circle, so that it is difficult to reduce the cost in terms of manufacturing. However, there is a problem from the viewpoint of manufacturing efficiency. On the other hand, in the method of applying heat,
When the temperature is raised to a certain temperature, there is an advantage that a spherical toner can be easily manufactured. However, in a method of applying heat by a dry method, the toner needs to be well dispersed in advance, and it is difficult to apply heat uniformly.

[0005] On the other hand, inorganic particles such as silica, alumina, and titanium oxide are generally added to the toner in an amount of several percent as a post-treatment agent in order to sufficiently impart fluidity and chargeability. However, when these inorganic fine particles are mixed and stirred with the carrier, they are buried in the toner particles or released from the toner particles, so that the fluidity and the chargeability greatly change with repeated use, and fog or white spots appear on the image. Has caused a problem. The released inorganic fine particles migrate (spent) to the surface of the carrier particles or adhere to the surface of the photoreceptor. It is conceivable to reduce the amount of the post-treatment agent to be released, but it is conceivable to reduce the amount of the post-treatment agent.However, simply reducing the amount of the agent reduces the amount of inorganic fine particles present on the surface of the toner particles. And the above problem becomes significant.

Therefore, 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, under dry conditions, it is difficult to uniformly fix the fine particles on the surface of the toner particles, particularly on the concave portions of the surfaces of the small-sized toner particles and the irregular toner particles.
If the fine particles are not fixed uniformly on the toner particle surface,
During repeated use, the surface state changes due to detachment of the post-treatment agent from the toner surface, the charge imparting member (carrier, regulating blade, etc.) due to the detached post-treatment agent, and the charge amount greatly changes due to contamination of the photoreceptor. This may cause noise such as fogging and white spots on the top.

Japanese Patent Application Laid-Open No. 63-106667 discloses a technique for fixing fine particles to the surface of toner particles under a wet condition. However, it is necessary to control the processing temperature to be equal to or higher than the glass transition point of the constituent resin. For this reason, in the processing step, aggregation between toners becomes a problem. Also, a method of immobilizing a surface treatment agent such as silica on the surface of toner particles using a medium such as glass beads in a wet process is known, but it is difficult to control the adhesion strength with such a technique, and In addition, there is a problem of media contamination in which a contamination component of the media adheres to the surface of the toner particles.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to suppress the generation of coalesced particles and to quickly and efficiently change the particle shape from an irregular shape to a perfect circle. It is an object of the present invention to provide a method for producing resin particles or a toner, which can be arbitrarily controlled to a spherical shape close to.

Further, the present invention can efficiently and arbitrarily control the particle shape from an irregular shape to a spherical shape close to a perfect circle in a short time and efficiently while suppressing the generation of coalesced particles. It is an object of the present invention to provide a method for producing resin particles or a toner capable of uniformly fixing fine particles on the particle surface with an appropriate strength.

[0010]

The present invention is characterized in that ultrasonic energy is applied to a dispersion obtained by dispersing at least resin particles in a resin-insoluble medium to make the resin particles spherical. The present invention relates to a method for producing resin particles.

The present invention is further characterized in that ultrasonic energy is applied to a dispersion obtained by dispersing toner particles comprising at least a resin and a colorant in a resin-insoluble medium, and the toner particles are made spherical. The present invention relates to a method for producing a toner.

Hereinafter, the method for producing the toner will be described in detail. The method for producing the resin particles is the same as the method for producing the toner except that the resin particles do not contain a toner component such as a colorant contained in the toner particles. It is. The present invention does not prevent the resin 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.

In the method of the present invention, ultrasonic energy is applied to a dispersion obtained by dispersing toner particles in a medium. More specifically, ultrasonic waves are propagated in a medium to apply ultrasonic vibration to toner particles. By applying ultrasonic energy to the toner particles in the medium as described above, the generation of coalesced particles can be suppressed, the particle shape can be efficiently controlled to a spherical shape close to a perfect circle, and the particle shape can be made uniform. Can be achieved. That is, when ultrasonic energy is applied, bubbles and heat are generated in the medium. It is considered that the gas bubbles generated at this time are formed by the growth of gas nuclei such as minute water vapor attached to the particle surface, or by the gas components contained in the medium growing as gas bubbles. Thereafter, the bubbles repeat the expansion and contraction movements and eventually disappear. When the bubble changes from contraction to expansion, a spherical shock wave is generated, and when the bubble collapses and disappears, a high pressure (thousands of atmospheres) is generated in the vicinity thereof (cavitation phenomenon). It is presumed that the mechanical force (shock wave and pressure) and heat due to such a phenomenon act on the toner particles relatively uniformly, and the toner is efficiently sphericalized while suppressing the generation of coalesced particles.

The frequency and intensity of the applied ultrasonic energy may be appropriately selected according to the desired shape of the particles. Generally, the frequency is 10 to reduce the processing time and prevent the generation of coalesced particles. 30 kHz, preferably 1
It is desirable to set the intensity to 5 to 20 kHz and the intensity to 3 to 40 W / cm ² , preferably 6 to 30 W / cm ² . In this specification, the intensity of the ultrasonic energy means a value obtained by dividing the amount of the ultrasonic energy by the area of the surface on which the ultrasonic wave is oscillated.

As a means for applying such ultrasonic energy, a commercially available ultrasonic oscillator, for example, a multiple ultrasonic dispersion device for production (MUS600TCVP-5; manufactured by Nippon Seiki Seisakusho) or the like can be used. . Further, a vibration element of an apparatus having an ultrasonic generator such as a circulation homogenizer (manufactured by Nippon Seiki Seisakusho) may be placed in the dispersion liquid to apply ultrasonic energy.

The application time of the ultrasonic energy depends on the frequency and intensity of the applied ultrasonic energy, the concentration of the dispersion to be irradiated with the ultrasonic wave, the total volume of the dispersion, the degree of spheroidization of the target particles, and the like. . When the ultrasonic wave is applied, the temperature of the dispersion increases, and it is not preferable that the state in which the temperature exceeds the softening point of the resin lasts for a long time, causing the aggregation of particles. Therefore, it is necessary to appropriately select the ultrasonic irradiation time so that the intended degree of spheroidization is achieved until the liquid temperature of the dispersion reaches the softening point of the resin constituting the particles. From the viewpoint of manufacturing efficiency, the shorter the irradiation time, the better. Further, the treatment may be performed while cooling the dispersion liquid from the inside and / or the outside as necessary.

As a guide for the conditions of the ultrasonic treatment step, the product of the applied ultrasonic energy (W) and the application time (minute) is divided by the volume (cc) of the dispersion liquid to be subjected to the treatment. It is useful to refer to whether the calculated value is 15 or more, preferably 15 to 50. By controlling the above value within the above range, it is possible to more easily set the setting conditions for making the toner particles spherical and fixing the fine particles described later.

In the present invention, the average particle size and the particle size distribution of the toner particles subjected to the ultrasonic treatment are almost directly reflected on the average particle size and the particle size distribution of the toner after the ultrasonic treatment. It is preferable to control the average particle size and particle size distribution to desired values. The average particle size of the toner particles subjected to the ultrasonic treatment is not particularly limited, but may be 2 to 10 μm.
m is preferable. In particular, in the present invention, the average particle diameter of 2 to which the shape control and surface treatment are difficult by the conventional method is difficult.
It is effective in the area of 7 μm. When the average particle diameter of the toner particles is too large, the resolution of the copied image is poor. On the other hand, when the average particle diameter is too small, it is difficult to handle each toner particle as a particle.

The medium constituting the dispersion is not particularly limited as long as the toner particles, particularly the resin constituting the particles, are not dissolved. Examples of the medium include water, methyl alcohol, ethyl alcohol, IPA (isopropyl alcohol), and petroleum-based carbon. Hydrogen (isopar) and the like can be mentioned. It is preferable to use water from the viewpoint of production cost and safety.

Further, a dispersant and / or a dispersing aid may be added to the dispersion. Examples of the dispersant include gelatin, gum arabic, agar, and cellulose derivatives (for example,
Polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylate, polymethacrylate, etc., poorly soluble inorganic salts (eg, calcium phosphate, etc.), hydrophilic silica, and the like. As the dispersing agent, a surfactant is usually used, and a natural surfactant such as aponin, a nonionic surfactant such as an alkylene oxide, glycerin or glycidol, carboxylic acid, sulfonic acid, phosphoric acid, and sulfate ester And anionic surfactants containing an acidic group such as a phosphoric acid ester group, such as sodium alkyl ether sulfate and sodium linear alkylbenzene sulfonate.

After the ultrasonic treatment as described above, the dispersion is filtered, the residue is washed with water, and dried to obtain a toner having a controlled shape. Further, the toner thus obtained has a relatively small variation in shape. For example, an average circularity of 0.
947, the average circularity can be increased to 0.995 by subjecting the toner particles having the circularity standard deviation of 0.045 to the ultrasonic treatment as described above to approximately 1.00 by selecting the conditions. , And the circularity standard deviation is set to 0.025 by selecting conditions.
Can be reduced.

In the method of the present invention, by dispersing the fine particles in the dispersion, another excellent effect that the fine particles can be efficiently and uniformly fixed to the surface of the toner particles with appropriate strength. Is also obtained. That is, by applying ultrasonic energy to the toner particles in the presence of the fine particles as described above, while suppressing the generation of coalesced particles, the toner particle shape is efficiently changed from an irregular shape to a perfect circle without variation. Not only can it be arbitrarily controlled to a close spherical shape, but also the fine particles can be efficiently and uniformly fixed on the surface of the toner particles with appropriate strength. Uniformity of fine particles on the toner particle surface,
In addition, it is considered that the immobilization at an appropriate strength is achieved by mechanical force (shock wave and pressure) due to the above-described cavitation phenomenon or the like. In this way, by fixing the fine particles uniformly on the surface of the toner particles with appropriate strength, the release of the fine particles from the toner particles is suppressed, and the deterioration of the chargeability and the fluidity during repeated use is prevented. In addition, an excellent image free of image noise can be provided for a long time.

As the fine particles, known inorganic fine particles and / or organic fine particles used as a fluidizing agent for the toner in the field of electrophotography and the like can be used. Specific examples of the inorganic fine particles include, for example, silica, alumina, titania and the like. Specific examples of the organic fine particles include, for example, polystyrene, polymethyl (meth) acrylate,
Resin fine particles such as Teflon, silicone, benzoguanamine and melamine can be exemplified. When inorganic fine particles are used, the fine particles are preferably subjected to a surface treatment with a known hydrophobizing agent, for example, hexamethylene disilazane (HMDS), dimethyldichlorosilane, various silicone oils, and the like. The average primary particle size of these fine particles is not particularly limited as long as it can impart fluidity to the toner. However, from the viewpoint of sticking to the toner particles and dispersibility of the fine particles, the average primary particle size is 1/10 or less, preferably 1/10 or less, of the average particle size of the toner particles. 100
It is desirable to set it to １／1/1000.

The amount of the fine particles is 0.1 to 5.0 parts by weight, preferably 0.2 to 2.0 parts by weight, based on 100 parts by weight of the toner particles in the dispersion. As described above, the amount of the fine particles used in the present invention is relatively small. This is because, in the present invention, even when the amount of the fine particles used is small, the particles can be efficiently fixed to the toner particles by the above ultrasonic energy.

When the fine particles are fixed to the toner particles as described above, after the ultrasonic treatment, the dispersion is filtered, the residue is washed with water, and dried, whereby the shape is uniformly controlled in the same manner as described above. In addition, a toner in which fine particles are well fixed is obtained. For example, when 1.3 parts by weight of fine particles are added to 100 parts by weight of toner particles, 80% or more, preferably 90% or more of fine particles are efficiently and moderately strong.
It can be fixed uniformly.

In the method of the present invention, in order to reduce aggregation between particles during drying and to impart fluidity of powder particles after drying, the toner obtained as described above has an average primary Particle size 5 to 500 nm, preferably 6 to 10
It is preferable to add and mix 0 nm inorganic particles. In addition, as the inorganic particles added here, in addition to those exemplified in the description of the inorganic fine particles, 0.1 to 5 μm
Large diameter particles such as strontium titanate.

In the present invention, the toner particles dispersed in the medium consist of at least a resin and a colorant, and may be produced by any known method. Known methods include, for example, a dry method such as a pulverization method, a wet method such as an emulsion dispersion granulation method, an emulsion polymerization method, and a suspension polymerization method. In the present invention, the pulverization method is effective. The reason is that amorphous toner particles are generally obtained by the pulverization method, and the toner particles can be efficiently sphericalized by the method of the present invention, and fine particles can be fixed well. It is generally known that toner particles having a high degree of circularity can be obtained by a wet method, but fine particles can also be satisfactorily fixed on the surface of the toner particles according to the present invention.

In the case of producing toner particles using a pulverization method, a resin, a colorant and other toner components are mixed by a mixer such as a Henschel mixer, melted and kneaded, cooled, and then coarsely and finely pulverized. And, if desired, classification. In the present invention, it is preferable to control the average particle size and the particle size distribution of the toner particles as described above. In this specification, the average particle size of the toner particles indicates a volume average particle size, and is a value measured using a Coulter Multisizer (manufactured by Coulter Counter Co., Ltd.) at an aperture diameter of 50 μm.

As the resin constituting the toner particles, any resin known in the field of electrophotography and the like can be used, for example, polyester resin, styrene resin, (meth)
Acrylic resin, styrene- (meth) acrylic resin,
Examples thereof include a polyamide resin, a polyurethane resin, and an epoxy resin. The resins may be used alone or as a mixture.

As the coloring agent, known pigments and dyes are used. For example, carbon black, aniline blue,
Calcoil Blue, Chrome Yellow, Ultramarine Blue, Dupont Oil Red, Quinoline Yellow, Methylene Blue Chloride, Copper Phthalocyanine, Malachite Green Oxalate, Lamp Black, Rose Bengal, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 184, C.I.
I. Pigment Yellow 97, C.I. I. Pigment
Yellow 12, C.I. I. Pigment Yellow 17,
C. I. Solvent Yellow 162, C.I. I. Pigment Yellow 180, C.I. I. Pigment Yellow 185, C.I. I. Pigment Blue 15: 1, C.I.
I. Pigment Blue 15: 3 and the like. The amount of the coloring agent is 0.5 to 100 parts by weight of the resin.
10 to 10 parts by weight, preferably 0.5 to 8 parts by weight, more preferably 1 to 5 parts by weight.

As other toner components, the toner particles may contain a charge control agent, a release agent, a magnetic material, and the like. As the charge control agent, known charge control agents can be used. For example, salicylic acid metal complexes, metal-containing dyes such as azo-based metal compounds, and high molecular acids such as copolymers containing maleic acid as a monomer component. , Quaternary ammonium salts, azine dyes such as nigrosine, triphenylmethane compounds, carbon black and the like.

As the release agent, known release agents can be used, for example, polyethylene wax, polypropylene wax, carnauba wax, rice wax, sasol wax, montan ester wax, Fischer-Tropsch wax and the like. it can. As the magnetic material, for example, ferrite, magnetite, iron, etc.
Known magnetic fine particles can be used.

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. Hereinafter, the present invention will be described in more detail with reference to Examples.

[0034]

EXAMPLES (Production of Polyester Resin A) Polyoxypropylene (2,2) -2,2 was placed in a gas four-necked flask equipped with a thermometer, a stainless steel stirrer, a falling condenser, and a nitrogen inlet tube. -Bis (4-hydroxyphenyl) propane (PO), polyoxyethylene (2,
0) -2,2-bis (4-hydroxyphenyl) propane (EO) and terephthalic acid (TPA) were added along with a polymerization initiator (dibutyltin oxide). Molar ratio (P
O: EO: TPA) was 4.0: 6.0: 9.0. This was reacted by heating while stirring and heating under a nitrogen stream in a mantle heater.
The progress of the reaction was followed by measuring the acid number. When a predetermined acid value was reached, each reaction was terminated and cooled to room temperature to obtain a polyester resin A. The obtained polyester resin A was roughly crushed to a particle size of 1 mm or less and used in the production of the following toner. The physical properties of the polyester resin A obtained here were determined by the number average molecular weight (Mn) =
3300, weight average molecular weight (Mw) / number average molecular weight (M
n) = 4.2, glass transition temperature (Tg) = 68.5 ° C.
Softening point (Tm) = 110.3 ° C, acid value = 3.3 KOHm
g / g and hydroxyl value = 28.1 KOH mg / g.

(Production of Pigment Masterbatch) The pigments used in the production of full-color toners are thermoplastic resin used in Examples and CI Pigment Yellow 180, respectively.
(Clariant), CIigmentBlue 15-3 (Dainippon Ink), and CI Pigment Red 184 (Dainippon Ink) at a weight ratio of 7: 3 in a pressure kneader.
Kneading was performed at 120 ° C. for 1 hour. After cooling, the mixture was roughly pulverized with a hammer mill to obtain a pigment master batch having a pigment content of 30% by weight.

(Production of Toner A) Polyester Resin A9
0.7 parts by weight, 13.3 parts by weight of CI Pigment Yellow 180 (manufactured by Clariant) master batch and 2 parts by weight of oxidized low molecular weight polypropylene (100TS: manufactured by Sanyo Chemical Co .; softening point 140 ° C, acid value 3.5) Is thoroughly mixed with a Henschel mixer, and then twin-screw extruder (PCM-
30: manufactured by Ikegai Iron Works Co., Ltd.), and melted and kneaded, and then cooled. The obtained kneaded material was rolled to a thickness of 2 mm with a cooling press roller, cooled with a cooling belt, and coarsely pulverized with a feather mill. Then, the average particle size is 10 to 12 by a mechanical pulverizer (KTM: manufactured by Kawasaki Heavy Industries, Ltd.).
After crushing to a mean particle size of 6.8 μm with a jet grinder (IDS: manufactured by Nippon Pneumatic Industries, Ltd.), the fine powder was classified into a rotor classifier (Tiplex classifier type: 100ATP: manufactured by Hosokawa Micron Corporation) using a volume average particle size of 7.47 μm,
Yellow toner A (toner A) having an average circularity of 0.947 and a circularity of SD of 0.033 was obtained.

(Production of Toner B) CI Pigment Yellow 1
80 (Made by Clariant) master batch
t A method for producing toner A, except that the master batch was changed to Blue 15-3, the amount of the master batch was changed to 10 parts by weight, and the amount of the polyester resin A was changed to 93 parts by weight. Magenta toner B (toner B) (volume average particle diameter 7.44 μm, average circularity 0.948, circularity SD 0.032) was obtained.

(Production of Toner C) CI Pigment Blue 15-
Cyan toner C (toner C) (volume average particle size 7.4) in the same manner as in the method for producing toner B, except that the master batch of No. 3 was replaced by the master batch of CI Pigment Red 184.
0 μm, average circularity 0.948, circularity SD 0.03
3) was obtained.

EXPERIMENTAL EXAMPLE 1 Example 1 To 100 parts by weight of toner A, hydrophobic silica (TS-5) was used.
00; manufactured by Cabot Corporation, BET specific surface area: 225 m ² / g)
0.8 parts by weight and hydrophobic silica (AEROSIL90G (manufactured by Nippon Aerosil Co., Ltd.) treated with hexamethylene disilazane;
BET specific surface area 65m ² / g, hydrophobicity 65% or more) 0.5
Parts by weight, and a peripheral speed of 30 m using a Henschel mixer
/ S for 30 seconds. After that, the toner particles are
g of a surfactant (22% sodium alkyl ether sulfate) at a concentration of 0.3% in an aqueous solution of 20 cc (20 cc).
C). Next, after stirring for 5 minutes with a roll mill (120 rpm), a vibrating element (φ36 mm, vibrator output 6 W / cm) of a circulation type homogenizer (Nippon Seiki Seisakusho) was used.
² ) One is installed directly on the medium, the frequency is 15kHz,
Ultrasonic energy with an intensity of 6 W / cm ² was applied for 5 minutes (ultrasonic treatment). Then, the temperature of the dispersion was measured, and immediately the flow type particle analyzer (FPIA-2000: Sysme) was used.
x company).

Examples 2 and 3 Ultrasonic treatment was carried out in the same manner as in Example 1, except that the treatment time with ultrasonic energy was changed to 6 minutes and 7 minutes, respectively. Then, the dispersion temperature and the particle shape were measured in the same manner as in Example 1.

Examples 4 to 6 Ultrasonic waves were produced in the same manner as in Example 1 except that the transducer output was changed to 15 W / cm ² , and the processing time by ultrasonic energy was changed to 2, 3, and 4 minutes, respectively. Processing was performed. Then, the dispersion temperature and the particle shape were measured in the same manner as in Example 1.

Examples 7 to 9 Ultrasonic treatment was performed in the same manner as in Example 1 except that the transducer output was changed to 30 W / cm ² , and the processing time by ultrasonic energy was changed to 1 minute, 2 minutes and 3 minutes. Was done. Then, the dispersion temperature and the particle shape were measured in the same manner as in Example 1.

Comparative Example 1 Measurement was performed in the same manner as in Example 1 except that no ultrasonic treatment was performed.

Comparative Example 2 Toner A (1.5 g) was dispersed in 20 cc (80 ° C.) of a 0.3% surfactant (22% sodium alkyl ether sulfate) solution. The dispersion thus obtained was vigorously stirred with a stirrer at 500 rpm for 30 minutes, and then subjected to a flow type particle analyzer (FPIA-2).
000: Sysmex). Although the shape was spherical to some extent, the particle size increased, and the toners were fused and aggregated.

The measurement results obtained in the above Examples and Comparative Examples are shown together with the processing conditions in a table.

[Table 1]

[0046]Experimental example 2 Example 10 Hydrophobic silica (TS-5) was used with respect to 100 parts by weight of toner A.
00; manufactured by Cabot Corporation, BET specific surface area: 225 m^Two/ G)
0.8 parts by weight and hydrophobic silica (AEROSIL90G (Japan
Hexamethylene disilazane treated product of Aerosil Co., Ltd.)
BET specific surface area 65m^Two/ G, degree of hydrophobicity 65% or more) 0.5
Parts by weight, and a peripheral speed of 30 m using a Henschel mixer
/ S for 30 seconds. Then, the toner particles are
g, surfactant (22% alkyl ether sulfate)
2000cc of 1.5% aqueous solution
(40 ° C.). After stirring thoroughly, circulate
Vibration element (φ36m) of the MONIZER (Nippon Seiki Seisakusho)
m, vibrator output 30W / cm ^Two10) Directly apply 10 media
15 kHz frequency, 30 W / cm strength^TwoSuper
Sonic energy was applied for 10 minutes. Then immediately dispersed
The temperature of the liquid is measured, and the flow particle analyzer (FPIA-
2000: Sysmex). Got
The aqueous dispersion was filtered, washed repeatedly with water, dehydrated and dried.
Drying is carried out at a drying temperature of 80 ° C.
D (Toner D) was obtained.

Examples 11 and 12 Ultrasonic treatment was performed in the same manner as in Example 10 except that toner B or toner C was used instead of toner A. Then, in the same manner as in Example 10,
The dispersion temperature and the particle shape were measured to obtain a magenta toner E (toner E) and a cyan toner F (toner F), respectively.

The measurement results obtained in the above examples are shown together with the processing conditions in a table.

[Table 2]

[0049] 1.0 g of toner D was taken, roasted, and the residue was measured to be 0.012 g.

Comparative Example 3 Hydrophobic silica (TS-5) was used for 100 parts by weight of toner A.
00; manufactured by Cabot Corporation, BET specific surface area: 225 m ² / g)
0.8 parts by weight and hydrophobic silica (AEROSIL90G (manufactured by Nippon Aerosil Co., Ltd.) treated with hexamethylene disilazane;
BET specific surface area 65m ² / g, hydrophobicity 65% or more) 0.5
The mixture was mixed for 3 minutes at a peripheral speed of 30 m / s by a conventional Henschel mixer. The toner thus obtained was washed with distilled water, dehydrated, dried at a drying temperature of 80 ° C., and 1.0 g of the dried toner was roasted and the residue was measured. Was.

Experimental Example 3 Example 13 1.0 part by weight of strontium titanate fine particles (BET specific surface area 9 m ² / g) was added to 100 parts by weight of the toner D, E or F obtained in Experimental Example 2, and mixed. Processing, 1
As a result, a yellow toner G, a cyan toner H, and a magenta toner I of a component system were obtained.

Comparative Example 4 Hydrophobic silica (TS-500; manufactured by Cabot Corporation, BET specific surface area: 22) based on 100 parts by weight of toner A, B or C
5m ^{2 /} g) 0.8 parts by weight and hydrophobic silica (AEROSIL
Hexamethylene disilazane treated product of 90G (manufactured by Nippon Aerosil Co., Ltd.), BET specific surface area 65 m ² / g, hydrophobicity 65%
0.5 parts by weight) were added and mixed with a Henschel mixer at a peripheral speed of 30 m / s for 3 minutes. Then, strontium titanate fine particles (BET specific surface area 9 m ² /
g) 1.013 parts by weight was added and mixed to obtain one-component yellow toner J, cyan toner K, and magenta toner L.

Evaluation The above toners G to I and toners J to L were respectively mounted on a printer Color Page Pro (manufactured by Minolta), and 3000 specific images using three colors were output.
The following items were evaluated at the initial stage and after 3000 images were printed. (Fog) A character pattern having a B / W ratio of 5% is imaged as a Y (yellow) image, an M (magenta) image, and a C (cyan) image, and the obtained image is visually observed, and is displayed on an image of each color. Was evaluated according to the following ranking. In addition, the evaluation result described the worst one among the results of each color. ：: Fog was hardly recognized by visual evaluation; Δ: Slight fog was recognized, but there was no practical problem; ×: Fogging was present over the entire surface, and there was a practical problem.

(Blank) The character image is imaged as an R (red) image, a G (green) image, and a B (blue) image in which two color toners are superimposed, and the obtained image is visually observed. The void in the image of each color was evaluated according to the following ranking. Hollowout refers to a phenomenon in which a central portion of a character (line portion) remains on a transfer belt (drum) during transfer, thereby causing an image defect in the character portion on paper. In addition, the evaluation result described the worst one among the results of each color. ：: no hollowing occurred on the image; Δ: slight hollowing occurred on the image but no practical problem; ×: many hollowing occurred on the image, practical There was a problem.

(Transferability) The following ranking was made based on the ratio of the amount of toner adhered on the photosensitive drum to the amount of toner adhered on paper when a 50 mm square solid pattern image was imaged as a Y image, an M image, and a C image. Was evaluated according to In addition, the evaluation result described the worst one among the results of each color. ：: The above ratio was 80% or more; Δ: The above ratio was 70% or more and less than 80%; ×: The above ratio was less than 70%.

(White spots) Half images are converted into Y images, M images,
Image as a C image, and visually observe the obtained image,
The white spot on the image of each color was evaluated according to the following ranking. The white spot refers to a white spot-like image defect in a solid portion, and is mainly caused by contamination of the photoconductor (adhering of a post-processing agent or the like). In addition, the evaluation result described the worst one among the results of each color. ：: no white spots occurred on the image; Δ: slight white spots on the image but no problem in practical use; ×: many white spots on the image, practical There was a problem.

The results of the above evaluation are shown in the table.

[Table 3]

[0058]

According to the method of the present invention, a spherical toner can be manufactured in a short time and efficiently while suppressing the generation of coalesced particles. Further, it is possible to obtain a toner having less variation in shape. Furthermore, by applying ultrasonic energy in the presence of the fine particles, an excellent effect that the fine particles are uniformly fixed to the toner particles with appropriate strength is also obtained,
Even in repeated use, free fluid particles are not generated so much, and good fluidity and chargeability can be maintained.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Minoru Nakamura 2-3-1, Azuchicho, Chuo-ku, Osaka-shi, Osaka Osaka International Building Minolta Co., Ltd. F-term (reference) 2H005 AA15 AB03 EA05 EA10

Claims (4)

[Claims] 1. A method for producing resin particles, comprising applying ultrasonic energy to a dispersion obtained by dispersing at least particles of a resin in a resin-insoluble medium to make the resin particles spherical. 2. A method for producing a toner, comprising applying ultrasonic energy to a dispersion obtained by dispersing toner particles comprising at least a resin and a colorant in a resin-insoluble medium to make the toner particles spherical. Method. 3. A frequency of 10 to 30 kHz and ultrasonic intensity.
Degree 3-40W / cm ^TwoOf ultrasonic energy
The method for producing a toner according to claim 2, wherein: 4. The method according to claim 2, wherein the ultrasonic energy is applied in the presence of inorganic fine particles and / or organic fine particles having an average particle diameter of 1/10 or less of the average particle diameter of the toner particles. A method for producing the toner described in the above.