JPH04190246A - Manufacture of toner for static charge image development - Google Patents

Abstract

PURPOSE:To obtain a toner of an incomplete spherical form having a sharp grain size distribution and a good cleaning property by adding a grain size controlling agent in a coagulation process in manufacturing the toner obtained by coagulating and fixing grains having a grain size of less than 1/2 of a desired toner grain size. CONSTITUTION:Additives of a polymerization starter, a coloring agent, a parting agent, etc., are added to a polymerization monomer, they are dispersed or dissolved uniformly by an ultrasonic dispersing machine, homogenizer, etc., to be a monomer system, which is added to a water medium including emulsion, and it is emulsified and dispersed by a homogenizer or the like to be polymerized. A temperature of polymerization is set at more than 40 deg.C, or generally a temperature of 50 deg.C - 90 deg.C. Grains of less than about 3mum can thus be obtained. A coagulating agent and a grain size controlling agent are then added to obtained polymer liquid to coagulate the grains so as to obtain a grain coagulated body of a desired grain size. The grain coagulated body is then heat processed at more than Tg of binder forming the grains for fixing the grains with each other sufficiently. Grains of incomplete spherical forms are then obtained through elimination of the grain size controlling agent, dehydration, cleaning, and drying processes.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a toner for developing an electrostatic image, and more particularly, to a method for producing a toner for developing an electrostatic image formed in electrophotography. .

[Prior Art] Many electrophotographic methods are known, as described in U.S. Patent No. 2,297,691, etc.
Generally, a photoconductive substance is used to form an electrical latent image on a photoreceptor by various means, the latent image is developed using toner, and the toner image is transferred to a transfer member such as paper as necessary. After the transfer, the image is fixed using heat, pressure, solvent vapor, etc. to obtain a copy. Furthermore, various methods have been proposed in the past as a method of developing using toner or a method of fixing a toner image, and a method that involves passing through each image forming process has been adopted.

Generally, toner is produced by melt-mixing colorants such as dyes and pigments and additives such as charge control agents in a thermoplastic resin, uniformly dispersing the mixture, and then using a pulverizer or a classifier to form the desired particles. Methods of manufacturing toner having a diameter are known.

Toner produced by these pulverization methods requires brittleness in the binder resin in order to provide sufficient pulverization properties, and in addition, since pulverization method toners have sharp protrusions, they are further pulverized in the developing device. or susceptible to powdering. As a result, increased fogging and scattering inside the machine occur, which is undesirable.

In order to solve these drawbacks of toner produced by pulverization, for example, Japanese Patent Publication No. 56-13945 discloses a method of obtaining spherical toner by a melt spray method, and Japanese Patent Publication No. 57-5167
In Publication No. 6, a small amount of organic solvent is added to amorphous toner,
A method of obtaining a spherical toner by carrying out stirring treatment under cooling is further disclosed in Japanese Patent Publication No. 36-10231, Japanese Patent Application Laid-Open No. 59-53856, and Japanese Patent Application Laid-open No. 59-61842.
A method of obtaining a spherical toner using a polymerization method is disclosed in Japanese Patent Application Publication No.

Since these spherical toners have a uniform shape, latent images, especially edge portions, are faithfully developed, resulting in high image quality. Furthermore, when a spherical toner is obtained by a polymerization method, it is easy to reduce the particle size of the particles, which leads to higher image quality.

As described above, the spherical toner solves some of the drawbacks of the toner obtained by the pulverization method, but since the obtained toner is perfectly spherical, the cleaning performance is poor.

In order to solve this drawback, Japanese Patent Application Laid-Open No. 60-220358 proposes a method of obtaining toner by salting out particles in an emulsion polymerization solution obtained by emulsion polymerization so that the particles have a particle size suitable for the toner particle size. is suggesting. Although imperfectly spherical toner can be obtained using this method, it is difficult to control the toner particle size in the salting out process, and the resulting toner particles have an extremely wide particle size distribution, requiring a classification process. I end up.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned problems.
The present invention provides a method for producing a toner with excellent cleaning properties.

[Means for Solving the Problems] An object of the present invention is to provide a method for producing a toner obtained by aggregating and fixing particles having a particle size of 1/2 or less of a desired toner particle size. , is achieved by adding a particle size control agent in the aggregation step.

The present invention will be explained in detail below.

As a result of intensive studies, the present inventors found that 1/1/2 of the desired toner particle size
In a method for producing a toner obtained by agglomerating and fixing particles having a particle size of 2 or less, the particle size distribution of the agglomerated particles is sharply controlled by adding a particle size control agent in the aggregation step. We have discovered that this is possible. For example, if only a flocculant is used in the aggregation step, agglomerated particles can be obtained efficiently, but there is almost no ability to control the particle size, resulting in a wide particle size distribution. Therefore, by adding a particle size control agent during the aggregation step, the particle size can be easily controlled during and after aggregation of particles.

An example of the method for manufacturing the toner of the present invention is shown below.

A monomer system in which other additives such as a polymerization initiator, colorant, mold release agent, etc. are added to a polymerizable monomer and uniformly dispersed or dissolved using an ultrasonic disperser, homogenizer, etc. It is added to an aqueous medium containing an emulsifier and emulsified and dispersed using a homogenizer or the like to perform polymerization. Polymerization temperature is 40℃
As mentioned above, - For boat fishing, it is best to set the temperature between 50°C and 90°C.

Particles of approximately 3 μm or less are thus obtained.

A coagulant and a particle size control agent are added to the polymerization solution thus obtained to aggregate the particles to obtain particle aggregates having a desired particle size. The coagulant and particle size control agent may be added at the same time or separately.

Further, the particle aggregates are heat treated with 7 g or more of a particle-forming binder in order to sufficiently bond the particles together. Thereafter, particles having an incompletely spherical shape are obtained through removal of the particle size control agent, dehydration, washing, and drying steps.

Examples of polymerizable polymers applicable to the present invention include styrene,
Styrene and its derivatives such as 0-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene: MEC 1J Methyl rulate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate , isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and other methacrylic acid esters; methyl acrylate , ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, etc. Acrylic acid esters include vinyl monomers such as acrylic acid or methacrylic acid conductors such as acrylonitrile, methacrylonitrile, and acrylamide.

These monomers can be used alone or in combination. Among the above-mentioned monomers, it is preferable to use styrene or a styrene derivative alone or in combination with other monomers as a polymerizable monomer in terms of the developing characteristics and durability of the toner.

Further, it is more preferable to add a polymer, copolymer, cyclized rubber, etc. having a polar group as an additive during polymerization of the vehicle body.

On the other hand, as the charge control substance added as necessary, generally known substances can be used. For example, nigrosine, azine dyes containing an alkyl group having 2 to 16 carbon atoms, metal compounds of monoazo dyes, metal compounds of salicylic acid, dialkyl salicylic acid, etc. are used.

As the colorant used in the present invention, known colorants can be used, such as carbon black, iron black, C, 1,
Direct Blue 1, C, 1, Direct Red 4, C
,1, Acid Red 1, C,1, Basic Red 1
, C,1, Modern Tread 30, C,1, Direct Blue 1, C,1, Direct Blue 2, C,1,
Acid Blue 9, C, 1, Acid Blue 15, C,
1, Basic Blue 3, C, 1, Basic Blue 5
,C,1,Mordan Bluer ,-C,1,Direct Green 6,C,1,Basic Green 4,C1,
Basic Green 6 grade dye, yellow lead, cadmium yellow, mineral fast yellow, navel yellow,
Naphthol Yellow S1 Hansa Yellow G1 Permanent Yellow NCG.

Tartrazine lake, molybdenum orange, permanent orange GTR, benzidine orange G1 cadmium red, permanent red 4R, watching red calcium salt, brilliant cardin 3B, fast violet B1 methyl violet lake, dark blue, cobalt blue, alkaline blue lake, Pigments include Victoria Blue Lake, Quinacridone, Rhodamine B1 Phthalocyanine Blue, Fast Sky Blue, Pigment Green B, Malachite Green Lake, and Final Yellow Green G.

Further, in order to use the toner as a magnetic toner, magnetic powder may be included. As such magnetic powder, a substance that is magnetized when placed in a magnetic field is used, and includes powder of ferromagnetic metals such as iron, cobalt, and nickel, and compounds such as magnetite and ferrite. In particular, in the present invention, since the toner is obtained using a polymerization method, it is necessary to pay attention to the polymerization inhibiting property and water compatibility of the colorant.
It is preferable to perform surface modification, for example, hydrophobic treatment using a substance that does not inhibit polymerization, such as coupling agent treatment or grafting treatment.

In particular, many dyes and carbon blacks have polymerization inhibiting properties, so care must be taken. A preferred method for surface treating dye systems includes a method in which a polymerizable carmer is prepolymerized in the presence of these dye systems, and the resulting colored polymerization is added to the monomer system. Further, carbon black may be subjected to a grafting treatment with a substance that reacts with the surface functional groups of carbon black, such as polyorganosiloxane, in addition to the same treatment as the above-mentioned dye.

In addition, as the mold release agent used in the present invention, paraffin
Examples include polyolefin waxes and modified products thereof, such as oxides and grafted products, as well as higher fatty acids, metal salts thereof, and amide waxes. It is desirable that these waxes have a softening point of 40 to 130°C, preferably 50 to 120°C, as determined by the ring and ball method (JIS K 2531).If the softening point is 40°C or lower, the blocking resistance and shape retention of the toner will be insufficient. and 130
If the temperature is higher than 0.degree. C., the releasability effect will be insufficient.

Such a mold release agent is preferably used in an amount of 5 to 30 parts by weight per 100 parts by weight of the polymerizable monomer.

As the polymerization initiator, any suitable polymerization initiator such as 2.2°-azobis-(2,4-dimethylvaleronitrile), 2.2°-azobisisobutyronitrile,
1.1'-azobis(cyclohexane-1-carbonitrile), 2.2'-azobis-4-methoxy-2,4
-Azo or diazo polymerization initiators such as dimethylvaleronitrile and other azobisisobutyronitrile (AIBN); benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxy carbonate, cumene hydroperoxide, 2,4-dichloro Examples include peroxide-based polymerization initiators such as benzoyl peroxide and lauroyl peroxide. These polymerization initiators are generally about 0.0% by weight of the polymerizable monomer.
5-10% initiator is sufficient.

Furthermore, a water-soluble polymerization initiator may be used in combination with the oil-soluble polymerization initiator and added to the aqueous medium.

Examples of water-soluble polymerization initiators that can be used in the present invention include persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide, 4.4°-azobiscyanovaleric acid, and 2,2°-azobis( 2-amidinopropane)
Dihydrochloride, t-butyl hydroperoxide, cumene hydroperoxide, etc. can be used. In particular, when persulfate is used, the sulfate anion radical (SO4-) that serves as the initiation active site exists on the surface of the monomer, and the particles are stabilized by the hydrophilic group of the 504-group and the electrification, resulting in a relatively uniform particle size. It is easy to obtain an emulsion having .

The amount used is preferably 0.01 to 10% by weight, particularly preferably 0.1 to 5% by weight, based on the polymerizable vehicle. If the amount of polymerization initiator is too small, the polymerizable monomer will not be completely polymerized and will remain in the toner, impairing the properties of the toner.

During polymerization, the following crosslinking agent may be present to produce a crosslinked polymer. For example, divinylbenzene, divinylnaphthalene, divinyl ether, divinyl sulfone, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol diacrylate. Methacrylate, 1.6-hexane gelicol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2.
2°-bis(4-methacryloxyjethoxyphenyl)propane, 2.2'-bis(4-acryloxyjethoxyphenyl)propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, General crosslinking agents such as dibroneopentyl glycol dimethacrylate and diallyl phthalate may be used as appropriate.

If these crosslinking agents are used in large amounts, the toner becomes difficult to melt, resulting in poor fixing properties. In addition, if the amount used is small, properties such as blocking resistance and durability necessary for toner will deteriorate, and during hot roll fixing, some of the toner will not completely adhere to the paper and will stick to the roller surface, causing the next It becomes difficult to prevent the offset phenomenon of transfer to paper. Therefore, the amount of these crosslinking agents used is 0.001 to 15% by weight, more preferably 0.1% by weight based on the total amount of monomers.
It is preferable to use it at ~10% by weight.

Chain transfer agents include alkyl mercaptans such as t-dodecyl mercaptan, lower alkyl xanthogens such as diisopropyl xanthogen, carbon tetrachloride, carbon tetrabromide, etc., and are used in an amount of 0 to 2% by weight based on the polymerizable carmer. Preferably.

The aqueous medium used in emulsion polymerization is mainly water. The weight ratio of the polymerizable monomer to the aqueous medium is preferably 40/60 to 90/10. If this ratio is too small, emulsion polymerization will be difficult, and if this ratio is too large, the yield will decrease.

As the emulsifier, anionic surfactants, cationic surfactants, amphoteric surfactants and nonionic surfactants can be used. Among these, it is preferable to use an anionic surfactant when producing a negative t' chargeable toner, and use a cationic surfactant when producing a positively chargeable toner. In these cases, in order to improve dispersion stability, it is preferable to use a nonionic surfactant in combination.

Examples of anionic surfactants include fatty acid salts such as sodium oleate and potassium castor oil, alkyl sulfate ester salts such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkylnaphthalene sulfonates. , dialkyl sulfosuccinates, alkyl phosphate ester salts, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl sulfate ester salts, and the like.

Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin, fatty acid ester, oxyethylene There are oxypropylene block polymers, etc.

Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride and stearyltrimethylammonium chloride.

Examples of zwitterionic surfactants include lauryltrimethylammonium chloride.

The amount of emulsifier used is 0.01 to 1% relative to the polymerizable carmer.
0% by weight is preferred, particularly 0.5-5% by weight. If the amount of emulsifier used is too small, stable emulsion polymerization will be difficult, and if it is too large, the resulting toner will have poor moisture resistance.

Stabilizers include polyvinyl alcohol, starch,
There are water-soluble polymers such as methylcellulose, carboxydimethylcellulose, and hydroxyethylcellulose, and these are preferably used in an amount of 0 to 1% by weight based on the polymerizable monomer.

Examples of coagulants used in the present invention include inorganic acids such as hydrochloric acid and sulfuric acid, organic acids such as formic acid and oxalic acid, and water-soluble metal salts of these acids and alkaline earth metals, aluminum, etc. . These coagulants can be used alone or in combination, but preferred coagulants are magnesium sulfate, aluminum sulfate, barium chloride, magnesium chloride, calcium chloride, sodium chloride, and/or a combination of these and an inorganic acid. These coagulants are 0.1
It is preferably used as a ~1.0% by weight aqueous solution, especially a 0.1-5% by weight aqueous solution.

In addition, the amount of coagulant is 0 based on the weight of emulsifier in the emulsion polymerization solution.
．． It is preferred to use 1 to 5 times, preferably 0.3 to 0.5 times. If the amount of coagulant used is too small, the particle coagulation effect will be insufficient, and if it is too large, it will deteriorate the environmental characteristics of the finished toner, and also inhibit the effect of the particle size control agent, leading to a change in particle size distribution. Wide particle aggregates are obtained.

Examples of particle size control agents used in the present invention are shown below.

(1) Poorly water-soluble inorganic salts calcium phosphate, magnesium phosphate, calcium sulfate, magnesium carbonate, calcium carbonate, calcium hydroxide, aluminum phosphate, zinc phosphate, zinc carbonate, aluminum hydroxide, magnesium hydroxide, etc. (2) Metals The particle size of such inorganic compounds such as oxide silica and alumina is 2 μm or less as a primary particle.
Furthermore, it is preferably 1 μm or less.

These poorly water-soluble inorganic salts may be used as they are in powder form, but there is a method of producing poorly water-soluble inorganic salts in water using substances such as sodium phosphate and calcium chloride and using them as they are. This is preferable because an inorganic compound in the form of fine particles and with good dispersibility can be easily obtained.

In general, the agglomeration of poorly water-soluble powdered inorganic salts is generally a strong aggregation state, and the particle size in this agglomeration state is also non-uniform, so when such powders are used, they must be carefully dispersed in water. It is often necessary to do so. However, if the method of producing a poorly water-soluble inorganic salt in water as described above is used, there is no such concern and a good dispersion state of the inorganic salt can be easily obtained.

Furthermore, when the poorly water-soluble inorganic salt is produced in water in this way, the water-soluble salts obtained together with the poorly water-soluble inorganic salt can be used as is as a coagulant.

Examples of reactions that produce poorly water-soluble inorganic salts are shown below.
It is not limited to these.

2 N 83 P O4+ 3 Ca Cj22 =C
a3 (PO4)2 + 6NaCf12Na3PO
4+3MgSO4= Mg3(P 04)2 + 3N a25O42Na
,, po4+AfL2 (SO4) 3=2 A Il
P Oa + 38 a 2 S O4N a 2
S O4+ Ca Ci12 = CaSOa +2Na
Cfl Na2 CO3+Mg SO4= MgCO3+Na25O4 Na 2 CO3+ Ca CfL 2 =CaCO
3+2NaCu 2Na,, po, +3ZnSO4= Zn3 (PO4)2 +3Na25O4N a 2
CO3+ Z n CA z =ZnCO3+2NaC
fL N a 2 CO3+ Z n S Oa = ZnCO
3+2Na, So.

Further, as the silica which is a metal oxide, for example, Aerosil a2oo is an anionic silica.

#300. #380 (manufactured by Nippon Aerosil Co., Ltd.) colloidal silica, and examples of cationic silica include aminoalkyl-modified colloidal silica.

In particular, when using silica as a particle size control agent, it is preferable to use cationic silica when the particles to be aggregated are negative, and to use anionic silica when the particles are positive.

These particle size control agents are preferably used in an amount of 0.5 to 10 parts by weight, more preferably 2 to 10 parts by weight, based on 100 parts by weight of the polymerizable polymer.
5 parts by weight. If it is less than 0.5 parts by weight, a sufficient particle size control effect cannot be obtained, whereas if it is more than 10 parts by weight, the effect of agglomerating the particles will be inhibited. Further, two or more of these particle size control agents may be used in combination.

In order to impart various characteristics to the obtained toner, for example, the following substances may be externally added.

l) Fluidity imparting agent: metal oxides (silicon oxide, aluminum oxide, titanium oxide, etc.), carbon black, carbon fluoride, etc. Each of them is more preferably subjected to hydrophobization treatment.

2) Abrasives: Metal oxides (strontium titanate, cerium oxide, aluminum oxide, magnesium oxide, chromium oxide, etc.), nitrides (silicon nitride, etc.), carbides (
silicon carbide, etc.) metal salts (calcium sulfate, barium sulfate, calcium carbonate, etc.), etc.

3) Lubricant 6 Fluorine resin powder (vinylidene fluoride, polytetrafluoroethylene, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.), etc.

4) Charge controllable particles, metal oxides (tin oxide, titanium oxide, zinc oxide, silicon oxide, aluminum oxide, etc.), carbon black, etc.

These additives are added to 0.1 parts by weight per 100 parts by weight of toner particles.
~10 parts by weight are used, preferably 01 to 5 parts by weight are used. These additives can be used alone or
You may use more than one in combination.

Particle size distribution measurement in the present invention will be described.

The measuring device is Coulter counter TA-11 type (
(manufactured by Coulter) and number average distribution.

Interface that outputs volume average distribution (manufactured by Nikkaki)
and CX-1 personal computer (manufactured by Canon)
The electrolyte is 1% Na using primary sodium chloride.
Prepare Cu*4 liquid.

As a measuring method, 0.1 to 5 mfl of a surfactant, preferably an alkylbenzenesulfonate salt, is added as a dispersant to 100 to 150 mj2 of the electrolytic aqueous solution, and 0.5 to 50 mg of a measurement sample is added.

The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment using an ultrasonic disperser for about 1 to 3 minutes, and
Using Type I, the particle size distribution of particles of 2 to 40 μm is measured using a 100 μm aperture to determine the volume average distribution and number average distribution.

The volume average particle diameter is obtained from the volume average distribution and number average distribution thus determined.

[Examples] Hereinafter, the present invention will be explained in detail based on Examples. still,
All parts are by weight.

Example 1 The above formulation was heated to 70° C. in a container and sufficiently dissolved and dispersed using a homomixer to obtain a monomer mixture.

On the other hand, prepare an aqueous medium according to the above recipe/? ! The temperature was set to 70°C. The above monomer composition was added to this, emulsified using a homomixer, and heated to 70°C under N2 atmosphere.

Polymerization was carried out for 10 hours. After cooling, an emulsion polymerization liquid was obtained.

The particle size of the emulsion polymer was 0.5 μm.

<Agglomeration step> The emulsion polymerization liquid 142 was mixed with Mg30.10 as a coagulant.
g, was added dropwise over 30 minutes to an aqueous solution 2I2 in which 8 g of aminoalkyl-modified colloidal silica was dissolved and dispersed as a particle size control agent, with sufficient stirring and while maintaining the liquid temperature at 30°C.

<Same-adherence process> After that, this mixed solution was transferred to an autoclave and heated at 120°C.
The mixture was heated and stirred for 30 minutes. After cooling, sodium hydroxide was added, the particle size control agent was removed, and the mixture was washed with water, filtered through I11, and dried to obtain incompletely spherical colored particles.

When the obtained particles were measured with a Coulter counter (aperture diameter 100 μm), the volume average diameter was 8.5 μm.
(coefficient of variation 25%) and had a sharp particle size distribution.

K1±1 In Example 1, C,1, Pigment Yellow 17,
C,1, Pigment Blue 15:3, aminoalkyl-modified colloidal silica was changed to calcium phosphate, and sodium hydroxide was changed to hydrochloric acid, but the same operation was carried out to obtain incompletely spherical colored particles.

When the obtained particles were measured with a Coulter counter (aperture diameter 100 μm), the volume average diameter was 8.8 μm.
(coefficient of variation 28%) and had a sharp particle size distribution.

Using the above recipe, the coagulant Mg5O, CaCl2
The same operation as in Example 1 was carried out except that - was changed to obtain incompletely spherical colored particles. When the obtained particles were measured with a Coulter counter (aperture diameter 100 μm), they had a volume average diameter of 8.2 μm (coefficient of variation 24%) and a sharp particle size distribution.

Using the above recipe, the same operations as in Example 1 were carried out to obtain incompletely spherical colored particles.

The obtained particles were measured with a Coulter counter (aperture diameter 10,100 μm), and the volumetric average diameter was 8.5 μm.
(coefficient of variation 30%) and had a sharp particle size distribution.

0.6 parts of hydrophobized fine silica powder was mixed with 100 parts of each of the particles obtained in Examples 1 to 4 to prepare a toner. 92 parts of acrylic coated ferrite carrier were mixed with 8 parts of the toner to form a developer.

The developer obtained in this way was used with Canon CLC-
When the image quality was evaluated using 500 copies, it was found that even after 20,000 copies, clear and fog-free color copies were obtained without any cleaning defects.

In Example 1, except that no particle size control agent was used.
A similar operation was performed to obtain incompletely spherical colored particles. The obtained particles were placed in a Coulter counter (aperture diameter 10
When measured at 0 μm), the volume average diameter was 9.6 μm (coefficient of variation 45%), which was a very broad particle size distribution.

[Effects of the Invention] As described above, according to the present invention, a toner that does not require a classification step, has a sharp particle size distribution, is imperfectly spherical, and has excellent cleaning properties can be obtained.

Claims (2)

[Claims] (1) A method for producing a toner obtained by aggregating and fixing particles having a particle size of 1/2 or less of a desired toner particle size, characterized in that a particle size control agent is added in the aggregation step. A method for producing a toner for developing an electrostatic image. (2) The method according to claim (1), wherein the particle size control agent is at least one selected from poorly water-soluble inorganic salts, silica, and alumina.