JP3473194B2 - Electrostatic image developing toner and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge image developing toner for developing an electrostatic latent image formed by an electrophotographic method or an electrostatic recording method, and a method for producing the same.

[0002]

2. Description of the Related Art A method of visualizing image information through an electrostatic charge image such as an electrophotographic method is currently used in various fields. In the electrophotographic method, an electrostatic latent image is formed on a photoreceptor by a charging and exposing process, is developed with a developer containing toner, and is visualized through a toner image transfer and fixing process. The developer used here includes a two-component developer composed of a toner and a carrier, and a one-component developer using a magnetic toner or a non-magnetic toner alone. The production of the toner is usually a thermoplastic resin. A kneading and pulverizing method is used in which the compound is melt-kneaded with a release agent such as a pigment, a charge control agent and a wax, cooled, finely pulverized, and further classified. Inorganic and organic fine particles for improving fluidity and cleaning properties are added to these toners as needed, and are attached to the surface of the toner particles.

In the usual kneading and pulverization method, the shape of the toner and the surface structure of the toner are indefinite, and the toner shape and the surface structure are intentionally changed although they are slightly changed depending on the pulverizability of the materials used and the conditions of the pulverization process. It is difficult to control. Further, in the case of a toner using a material having a particularly high pulverizability, the toner is often pulverized further due to mechanical force in the developing machine to cause generation of fine powder or change in toner shape. Due to these effects, in the two-component developer, fine powder adheres to the carrier surface to accelerate the charge deterioration of the developer, and in the one-component developer, the toner is scattered due to the expansion of the particle size distribution, and the toner shape The deterioration of the developability due to the change of the image quality may cause deterioration of the image quality. In addition, when a release agent such as wax is internally added to form a toner, the release agent is often exposed on the surface depending on the combination with a thermoplastic resin, and various effects are exerted upon development. In particular, in the case of a combination of a polyethylene wax and a resin which is imparted with elasticity due to a high molecular weight component and is slightly hard to pulverize, polyethylene is often exposed on the toner surface. Although these are advantageous in terms of releasability at the time of fixing and removal of untransferred toner from the photoconductor, and cleaning properties, they are easily transferred by the mechanical force of the polyethylene wax on the surface. Surface contamination of the body and carrier is likely to occur, leading to reduced reliability.

Further, since the toner has an irregular shape, the fluidity is not sufficient even when the fluidity aid is added,
During use, mechanical force causes fine particles on the toner surface to move to the toner recesses, and the fluidity decreases over time, resulting in deterioration of developability, transferability, and cleaning performance. Further, if the toner collected by cleaning is returned to the developing device and used again, the image quality is more likely to deteriorate. If the flowability auxiliary agent is further increased in order to prevent these, there arises a problem that black spots are generated on the photoconductor and auxiliary agent particles are scattered.

On the other hand, if the kneaded and pulverized toner is made into a spherical shape, the shape of the toner is less likely to change due to mechanical force, and the influence of the movement of the fluidity aid to the toner surface concave portion is reduced, so that the durability is improved. Further, usually, since the particle size selectivity in the development and transfer steps is relaxed, the maintainability of the developer is enhanced, and particularly in the toner recycling development in which the transfer residual toner on the photoconductor is returned to the developing machine and reused, Highly effective in improving the durability of the developer. Also, even if it is not completely spherical,
Smooth the surface of the toner obtained by the pulverization method,
Similar effects are often obtained even when the protrusions are deformed so as to be rounded. As an example of the spheroidizing or deforming treatment of the toner, a mechanical treatment by a hybridizer or the like or a dry treatment method such as hot air treatment is generally used. However, the former has a problem that it takes too much processing time per unit weight, and the spheroidization does not proceed sufficiently depending on the type of thermoplastic resin, and the latter usually has a high temperature of 300 ° C or higher during processing. Is required, and the resin is decomposed or oxidized, so that the chargeability is likely to be abnormal.
If it is attempted to improve the processing efficiency, there is a problem that the coalescence of the toner particles progresses and the particle size distribution largely moves to the large particle size side.

In addition, a method of obtaining a spherical toner by mixing a toner component in a volatile solvent and mixing with water containing a dispersion stabilizer to obtain a spherical toner (JP-A-63-25664), a unit amount containing a colorant Various methods have been proposed, such as a method in which a body composition is dispersed in water using a poorly water-soluble inorganic compound powder as a dispersion stabilizer, and then suspension polymerization is performed (JP-A-4-195153). There are problems in shape controllability and particle size distribution controllability, and it is not yet sufficient. By the way, a perfect spherical toner often causes a cleaning failure when combined with a blade cleaning method. Therefore, in order to obtain a toner having a shape close to a sphere but capable of blade cleaning, the toner is manufactured. It is desired to control the conditions.

[0007]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of eliminating the above-mentioned drawbacks of a toner obtained by the kneading and pulverizing method and the above-mentioned problems caused by spheroidizing of the toner. That is, an object of the present invention is to improve good developability, transferability, fixability, cleaning property and reduction of contamination of carrier and photoconductor by controlling toner shape and surface composition structure when used as a two-component developer. When it is used as a one-component developer, the toner shape and surface composition structure are controlled to prevent contamination of the developing roll and the photoconductor, and good developing property, transfer property, and Stable image maintainability is realized by the fixing property and cleaning property, and a high-quality copy image can be stably formed even when the toner collected by cleaning is returned to the developing machine and reused. An object of the present invention is to provide a toner for developing an electrostatic image and a method for producing the same. Another object of the present invention is to provide a method for producing a toner for developing an electrostatic charge image capable of performing precise shape control applicable to a blade cleaning method.

[0008]

A first method of producing a toner for developing an electrostatic charge image of the present invention comprises a step of mixing a binder resin and a colorant in a water-immiscible solvent. The composition is selected from calcium carbonate or tricalcium phosphate
A step of dispersing in a water-based medium in the presence of a dispersion stabilizer composed of a hydrophilic inorganic fine powder, and removing the solvent from the obtained suspension by heating and / or decompressing, and irregularly shaped particles having irregularities on the surface And a step of spheroidizing or deforming by heating at a temperature not lower than the glass transition point of the binder resin in the presence of a dispersion stabilizer comprising the hydrophilic inorganic fine powder. . The second method of the present invention for producing an electrostatic image developing toner comprises a step of mixing a binder resin and a colorant in a water-immiscible solvent,
The composition obtained is treated with calcium carbonate or tricalcium phosphate.
A step of dispersing in a water-based medium in the presence of a dispersion stabilizer consisting of a hydrophilic inorganic fine powder selected from the following, a step of diluting the obtained suspension with an aqueous medium, heating from the obtained suspension and / Or step of removing the solvent by reduced pressure to form irregularly shaped particles having irregularities on the surface, and in the presence of the dispersion stabilizer consisting of the hydrophilic inorganic fine powder, the temperature of the glass transition temperature of the binder resin or higher. It is characterized by having a step of spheroidizing or deforming by heating at. A third method for producing a toner for developing an electrostatic image of the present invention comprises a step of mixing a binder resin and a colorant in a water-immiscible solvent, and a composition obtained by using a viscosity modifier. Disperse in an aqueous medium containing calcium carbonate or phosphoric acid
A step of adding a dispersion stabilizer-containing solution consisting of a hydrophilic inorganic fine powder selected from lucium , a step of diluting the obtained suspension with an aqueous medium, a solvent from the obtained suspension by heating and / or reduced pressure By removing, and forming a particle of irregular shape having irregularities on the surface, and in the presence of a dispersion stabilizer consisting of the hydrophilic inorganic fine powder, by heating at a temperature not lower than the glass transition point of the binder resin It is characterized by having a step of spheroidizing or deforming.

In the present invention, the binder resin and the colorant are mixed in a water-immiscible solvent, and then the resulting composition is mixed with calcium carbonate or tricalcium phosphate in an aqueous medium.
After stirring and dispersing in the presence of a dispersion stabilizer consisting of a hydrophilic inorganic fine powder selected from the following , after rapidly evaporating the solvent while heating or depressurizing, after forming a thin film on the particle surface Since the solvent escapes from the inside of the particles, irregularly shaped toner particles having irregularities on the surface are formed. After completely evaporating the solvent, in the present invention,
Further, in the presence of the dispersion stabilizer consisting of the hydrophilic inorganic fine powder, heating is carried out at a temperature not lower than the glass transition point of the binder resin. Deformation proceeds, and by selecting temperature and time, the shape of particles can be controlled from amorphous to perfect spherical. It is considered that as a result, the colorant easily migrates to the vicinity of the surface of the toner particles, the surface strength increases, and the durability increases as a result.

In this case, in order to effectively suppress coalescence of particles during solvent evaporation, the binder resin and the colorant are mixed in a water immiscible solvent, and calcium carbonate or tribasic acid
After being dispersed in an aqueous medium in the presence of a dispersion stabilizer consisting of a hydrophilic inorganic fine powder selected from lucium , the obtained suspension is further diluted with the aqueous medium, and then heated and / or decompressed to form a solvent. Is effective. Also,
When dispersing in an aqueous medium in the presence of a dispersion stabilizer consisting of the hydrophilic inorganic fine powder, if a viscosity modifier having a high affinity for water is added, shear stress during dispersion works effectively, and is high. The particle size and particle size distribution can be controlled also in the solute concentration, and coalescence after dispersion can be prevented. Further, it is more preferable to dilute the suspension obtained by the dispersion treatment with an aqueous medium because the influence of the viscosity modifier or the like on the toner can be controlled to a minimum.

The present invention will be described in detail below. In the present invention, the binder resin and the colorant are mixed in the first step, but it is necessary to mix them in a solvent immiscible with water. Because, for example, JP-A-52-9
When mixed with a water-miscible organic solvent such as alcohol as disclosed in Japanese Patent No. 435, it is advantageous for dispersion and the like when hydrophobic silica is used together, but toner softened by heating This is because the particles agglomerate and the toner agglomeration cannot be prevented unless the toner concentration in the medium is considerably lowered.

In the present invention, the water-immiscible solvent means a solvent having a solubility in water of 30% or less at room temperature, specifically, ether solvents such as diethyl ether and isopropyl ether, dichloromethane, chloroform, Halogenated hydrocarbon solvents such as carbon tetrachloride, ester solvents such as ethyl acetate, methyl acetate and n-propyl acetate, hydrocarbon solvents such as toluene and xylene, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, or A mixture of them can be used.

Any known binder resin may be used in the present invention. Specifically, thermoplastic resins, for example, styrenes such as styrene, parachlorostyrene, α-methylstyrene, methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, Esters having unsaturated bonds such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate and 2-ethylhexyl methacrylate, nitriles having unsaturated bonds such as acrylonitrile and methacrylonitrile, vinyl methyl ether,
Vinyl ethers such as vinyl isobutyl ether, vinyl methyl ketone, vinyl ethyl ketone, vinyl ketones such as vinyl isopropenyl ketone, polymers or copolymers using monomers such as olefins such as ethylene, propylene and butadiene, or Examples thereof include mixtures thereof, and non-vinyl condensation resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins and polyether resins, and mixtures of these condensation resins with the vinyl resins, A graft polymer obtained by polymerizing a vinyl-based monomer in the presence of a polymer can be used.

As the colorant, carbon black, chrome yellow, hansa yellow, benzidine yellow, slen yellow, quinoline yellow, permanent orange GRT, pyrazolone orange, vulcan orange, watching red, permanent red, brilliant carmine 3B, brilliant carmine 6B. , DuPont Oil Red, Pyrazolone Red, Resole Red, Rhodamine B Rake, Rake Red C, Rose Bengal,
Examples thereof include aniline blue, ultramarine blue, calcoil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxalate and the like.

In the present invention, the binder resin may contain a magnetic material, a charge control agent, a release agent and the like as an internal additive, if necessary. Examples of the magnetic substance include metals such as ferrite, magnetite, reduced iron, cobalt, nickel and manganese, alloys thereof, and compounds containing such metals. As the charge control agent, a quaternary ammonium salt compound, a nigrosine compound,
Known dyes, triphenylmethane-based pigments and the like composed of complexes of aluminum, iron, chromium and the like can be mentioned.

As the release agent, low molecular weight polyolefins such as polyethylene, polypropylene and polybutene, silicone resins which are softened by heating, fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide and stearic acid amide. , Carnauba wax,
Plant waxes such as rice wax, candelilla wax, wax, jojoba oil, animal waxes such as beeswax, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, mineral / petroleum wax such as Fischer-Tropsch wax, And modified products thereof can be used. In the case of using these release agents, generally, in the case of a wax containing a wax ester having a large polarity such as carnauba wax and candelilla wax, the exposed amount of the wax on the toner particle surface is large, and conversely, polyethylene is used. In the case of a wax having a low polarity such as wax or paraffin wax, the exposure amount on the surface tends to decrease, but in the present invention, the exposure amount of these release agents on the toner particle surface becomes small. The increase / decrease in the amount of the release agent on the toner surface can be qualitatively observed with a scanning electron microscope, as well as the Annual Conference of Japan Hard Copy f.
or the Society of Electrophotography of Japan, p3
3 (1989) proposed X-ray electron spectroscopy method (X
It can be confirmed quantitatively by PS).

Add the above ingredients to a water immiscible solvent,
For example, after mixing with a mixer such as a ball mill, the resulting composition is treated with calcium carbonate or
Dispersion in an aqueous medium in the presence of a dispersion stabilizer consisting of a hydrophilic inorganic fine powder selected from tricalcium phosphate . Water is used as the aqueous medium, but a solvent miscible with water or a dispersant may be added. Examples of such miscible solvent include alcohols such as methanol and ethanol, and ketones such as acetone. In this step, it is necessary the presence of a dispersion stabilizer comprising the hydrophilic inorganic fine powder in order to prevent coalescence of the particles, thereby performing the sphering treatment of the toner particles in the practical toner concentration You can

In the present invention, as the dispersion stabilizer, calcium carbonate or tricalcium phosphate (hydroxypatite), which is a poorly water-soluble hydrophilic inorganic fine powder , is used.
These are easy to produce fine particles in the toner dispersion, and removing the Ru facilitates der.

In the present invention, a viscosity modifier may be further added. Examples of the viscosity modifier include glycerin, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol and the like. Further, in order to enhance dispersion stability, it is possible to use a surfactant together. Examples of the surfactant include anionic surfactants such as sulfate ester type, sulfonate salt and phosphate ester type, cationic surfactants such as amine salt type and quaternary ammonium salt type, polyethylene glycol type and alkylphenol ethylene oxide. Additive system,
Nonionic surfactants such as polyhydric alcohols can be used.

In the present invention, the dispersion treatment is carried out by adding the above dispersion stabilizer in an aqueous medium in an amount of 0.05% by weight to 3.0% by weight, more preferably 0.1% by weight to 2.0% by weight. It may be carried out by adding it to a concentration within the range and stirring. The dispersion stabilizer may be added in advance in the aqueous medium, but may be added successively during the dispersion treatment in order to narrow the particle size distribution. The stirring can be carried out by a known means such as a homomixer, whereby a suspension in which the composition of the above components is suspended in the form of fine particles is obtained.

The suspension obtained as described above is diluted with an aqueous medium as desired. Pure water is preferred as the aqueous medium. The toner concentration after dilution is 2 to 4
It is desirable to carry out so as to be in the range of 0 wt%. Thereby, coalescence of the toner particles can be effectively prevented.

The resulting suspension is then rapidly heated above the boiling point of the solvent and / or decompressed to remove the solvent. The heat treatment is preferably performed by rapidly raising the temperature and then generally maintaining the temperature at 50 to 90 ° C. for 1 to 6 hours. In addition, decompression is 7.4 ×
10 ⁴ Pa to 8.0 × 10 ³ Pa (560 to 60 mmH
Up to g) is preferred. As a result, a thin skin film is formed on the surface of the particles, and then the solvent inside escapes to form particles having irregularities on the surface.

After the solvent is removed by evaporation by heating and / or evaporation under reduced pressure, the suspension is further heated in the presence of the dispersion stabilizer consisting of the above-mentioned hydrophilic inorganic fine powder to form an irregular shape having irregularities on the surface. Sphericalize or deform particles.
The heating temperature is a temperature not lower than the glass transition point of the binder resin, and preferably in the range of 50 to 100 ° C. Then the suspension is cooled, filtered, washed with water and, if necessary,
A desired toner can be obtained by crushing and sieving. In that case, it is preferable to dissolve the dispersion stabilizer composed of the above-mentioned hydrophilic inorganic fine powder adhering to the surface of the toner particles formed by adding hydrochloric acid or sodium hydroxide to the suspension.

In the present invention, the obtained toner has a spherical shape with a controlled particle size, and it is particularly preferable that the average particle size is controlled within the range of 3 to 9 μm.

[0025]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples. In the following description, all "parts" mean "parts by weight". The particle size and its distribution were measured using Coulter Counter TA2 type (manufactured by Coulter Co.). Example 1 Styrene-n-butylmethacrylate resin 85 g (Mn = 9000, Mw = 120,000, Tg = 62 ° C.) (Copolymerization ratio 80:20, manufactured by Sanyo Chemical Co., Ltd.) Polyethylene wax fine powder (molecular weight 3000) 5 g (trade name) : PE130, manufactured by Hoechst) Carbon black (R330, manufactured by Cabot) 10 g Ethyl acetate 300 g The above components were mixed and dispersed by a ball mill for 10 hours. The obtained dispersion is treated with polyethylene glycol (#
1000, manufactured by Wako Pure Chemical Industries, Ltd.) and 1500 g of an aqueous solution containing 20% of tricalcium phosphate and 0.6%, and dispersed for 3 minutes by a homomixer. Then, the temperature was maintained at 83 ° C. in a water bath, and the temperature was maintained for 3 hours while stirring with a three-one motor. Thereby, particles having an average particle diameter of 6.5 μm were formed. When observing the shape of particles in the obtained suspension with a scanning electron microscope,
It was confirmed to have an irregular shape with no regularity having concave portions. The temperature of the suspension in this state was raised to 98 ° C., and the suspension was kept at that temperature for 3 hours to be spherical with almost the same particle diameter to obtain spherical particles.

After that, water is put into the water bath,
Cooled to 35 ° C. in 2 hours. Further, the pure water washing treatment by suction filtration was repeated 5 times. Then, it was dried with a vacuum dryer, crushed, and sieved with a 43 μm mesh to give an average particle size of 6.6.
μm toner was obtained. When the obtained toner was observed with a scanning microscope, it was confirmed that the toner was completely spherical. 0.8% of hydrophobic silica (diameter of specific surface area 12 nm) was added to each of the obtained spherical toner and irregular irregular toner having the above concave portions, and a ferrite carrier having an average particle diameter of 65 μm was added. A developer was obtained by mixing in a weight ratio of 5:95. The transfer efficiency of these developers was evaluated by a copying machine equipped with a brush cleaning mechanism (Vivace 500 remodeling machine, manufactured by Fuji Xerox Co., Ltd.), and the spherical toner showed a transfer efficiency of 98%, while The irregular toner having the regularity exhibited a transfer efficiency of 89%. Also, by repeatedly using this spherical toner,
When a continuous running test was conducted, the image quality was good even after copying 200,000 sheets, and when the toner-destroying fine powder in the developer was quantified, there was almost no change from the initial state and no difference was observed. .

[0027]

[0028]

Example 2 Polyester resin (bisphenol resin, manufactured by Kao Corporation) 90 g (Mn = 6000, Mw = 70000, Tg = 64 ° C.) Carbon black (BP1300, manufactured by Cabot Corporation) 10 g Diethyl ether / dichloromethane mixed solution (50) : 50) 300 g The above components were mixed and dispersed by a ball mill for 10 hours. The obtained dispersion is mixed with polyethylene glycol 2
Pour into 400 g of 0% aqueous solution and use a homomixer to 1
It was dispersed for a minute. Then, in 30 seconds, 50 g of 40 wt% calcium carbonate aqueous solution is added with stirring with a homomixer, and further stirred for 2 minutes to obtain 2000 g.
Of pure water. 80 ℃ in a water bath
The temperature was maintained for 4 hours while stirring with a three-one motor. As a result, irregularly shaped irregular particles having concave portions with an average particle diameter of 6.4 μm were obtained. The temperature of the suspension in this state was raised to 98 ° C. and kept at that temperature for 1 hour,
Spherical particles having substantially the same particle diameter were obtained to obtain spherical particles having a partially uneven surface.

After that, water is put into the water bath,
Cooled to 35 ° C. in 2 hours. Further, the pure water washing treatment by suction filtration was repeated 5 times. After drying with a vacuum dryer and disintegration, it was sieved with a 43 μm mesh to obtain a spherical toner having an average particle size of 6.4 μm. 0.8% of hydrophobic silica (diameter of specific surface area: 12 nm) was obtained for each of the obtained spherical toner and irregular irregular toner having the above concave portions.
Was added and mixed with a ferrite carrier having an average particle diameter of 50 μm in a weight ratio of 5:95 to obtain a developer.
For these developers, copy machines (Vivace500
Transfer efficiency was evaluated with a modified machine (Fuji Xerox Co., Ltd.), and it was found that this spherical toner showed a transfer efficiency of 99%, while the irregular toner having irregularities with a recess showed a transfer efficiency of 90%. Indicated. In addition, a continuous running test was conducted by repeatedly using the spherical toner.
Even after copying 50,000 sheets, the image quality was good, and no defective cleaning was observed.

[0031]

In the present invention, the binder resin and the colorant are mixed in a water-immiscible solvent, and the resulting composition is treated with charcoal.
An irregular shape with irregularities on the surface by dispersing in an aqueous medium in the presence of a dispersion stabilizer consisting of hydrophilic inorganic fine powder selected from calcium phosphate or tricalcium phosphate , removing the solvent by heating and / or reducing pressure After forming the particles of the above, in the presence of the dispersion stabilizer consisting of the above-mentioned hydrophilic inorganic fine powder, it is formed by spheroidizing or deforming by heating at a temperature above the glass transition point of the binder resin. The coalescence of the toner particles is prevented, the particle size distribution is easily controlled, and a spherical toner having a narrow particle size distribution can be obtained. Further, the toner obtained by the present invention realizes good developing property, transfer property, fixing property, cleaning property, reduction of contamination of carrier and photoreceptor, shows stable charging property, and is further cleaned by blade cleaning. It is possible to stably form a high-quality copy image even when the collected toner is returned to the developing machine and reused without causing defects.

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-6-313988 (JP, A) JP-A-6-63387 (JP, A) JP-A-4-78863 (JP, A) JP-A-3- 246554 (JP, A) JP-A-1-302270 (JP, A) JP-A-1-195460 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 9/08

Claims (4)

(57) [Claims] 1. A step of mixing a binder resin and a colorant in a water-immiscible solvent, and the obtained composition is calcium carbonate.
Alternatively, a step of dispersing in a water-based medium in the presence of a dispersion stabilizer composed of a hydrophilic inorganic fine powder selected from tricalcium phosphate , removing the solvent from the obtained suspension by heating and / or decompressing the surface. A step of forming irregularly shaped particles having irregularities, and a step of spheroidizing or deforming by heating at a temperature above the glass transition point of the binder resin in the presence of a dispersion stabilizer consisting of the hydrophilic inorganic fine powder A method for producing an electrostatic charge image developing toner, comprising: 2. A step of mixing the binder resin and the colorant in a water-immiscible solvent, and adding the resulting composition to calcium carbonate.
Alternatively, a step of dispersing in an aqueous medium in the presence of a dispersion stabilizer composed of a hydrophilic inorganic fine powder selected from tricalcium phosphate , a step of diluting the obtained suspension with an aqueous medium, the obtained suspension From the solvent by heating and / or reducing pressure to form irregularly shaped particles having irregularities on the surface, and in the presence of a dispersion stabilizer composed of the hydrophilic inorganic fine powder, the glass transition point of the binder resin. A method for producing a toner for developing an electrostatic charge image, comprising the step of spheroidizing or deforming by heating at the above temperature. 3. A step of mixing the binder resin and the colorant in a water-immiscible solvent, the obtained composition is dispersed in an aqueous medium containing a viscosity modifier, and calcium carbonate or
Is a step of adding a dispersion stabilizer-containing solution composed of a hydrophilic inorganic fine powder selected from tricalcium phosphate , a step of diluting the obtained suspension with an aqueous medium, and heating and / or heating from the obtained suspension. Removal of the solvent by reduced pressure, the step of forming irregularly shaped particles having irregularities on the surface, and in the presence of the dispersion stabilizer consisting of the hydrophilic inorganic fine powder, heated at a temperature not lower than the glass transition point of the binder resin The method for producing a toner for developing an electrostatic charge image, comprising the step of spheroidizing or deforming the toner. 4. A binder resin and a colorant are mixed in a water-immiscible solvent, and the resulting composition is treated with calcium carbonate or
Disperse in an aqueous medium in the presence of a dispersion stabilizer consisting of hydrophilic inorganic fine powder selected from tricalcium phosphate , and then remove the solvent by heating and / or reducing pressure to form irregularly shaped particles having irregularities on the surface. In the presence of a dispersion stabilizer composed of the hydrophilic inorganic fine powder, the particles formed by spheroidizing or deforming by heating at a temperature not lower than the glass transition point of the binder resin. Characteristic toner for developing electrostatic image.