JP2001249491A - Toner and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide nonmagnetic single-component developing toner and a method of manufacturing the toner such that polymerized toner is manufactured by an economical method in which the thermal energy for drying can be decreased and the classification process can be omitted and then an additive is externally added to the polymer toner. SOLUTION: The nonmagnetic single-component developing toner is manufactured in the following process. A polymerizable monomer composition containing at least a polymerizable monomer and a coloring agent is suspended and polymerized in a water-base dispersion medium containing a metal compound hardly soluble with water to produce color polymer particles. An acid or alkali is added to the suspension liquid containing the color polymer particles to convert the metal compound hardly soluble with water into a compound soluble with the medium. The suspension liquid is cleaned and dehydrated. The obtained wet color polymer particles are dried in a vacuum drying machine to obtain dry color polymer particles showing substantially no change in the particle size from the particles before dried and having <=0.21% water content measured by the method of weight reduction by heating at 105 deg.C. The particles are collected, to which an additive is externally added.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electrophotography, electrostatic recording,
More specifically, the present invention relates to an electrostatic image toner used for electrostatic printing and the like, and more particularly to a method for producing colored polymer particles (polymerized toner) by a suspension polymerization method. A non-magnetic one-component developing toner is manufactured by reducing thermal energy during drying and preventing thermal aggregation (fusion) of particles during drying, and externally adding an additive thereto. The present invention relates to a method and a non-magnetic one-component developing toner obtained thereby.

[0002]

2. Description of the Related Art In electrophotography and the like, as a toner for visualizing (developing) an electrostatic charge image, a fixing resin medium such as a thermoplastic resin and a coloring agent such as carbon black dispersed in the resin medium. Granulated compositions containing other property imparting agents are widely used. Conventionally,
As a method for producing the toner, a colorant and a charge control agent are added to the thermoplastic resin, and preliminarily mixed in a mixer, and then melt-kneaded in a heat kneader to disperse the colorant and the like in the resin.
A method is known in which after cooling, coarse pulverization and fine pulverization are performed, and then classification is performed so as to obtain granules having a desired particle size. However, such a method of producing a toner by a pulverization method has a complicated process, and in order to enhance the dispersibility of a colorant or the like in a resin, it is necessary to knead the mixture at a high temperature for a long time. Is insufficient, and it is difficult to produce a toner having uniform electric or magnetic properties and satisfactory developing characteristics.

On the other hand, a colorant and other property imparting agents are added to a polymerizable monomer, and the resulting mixture is uniformly dispersed to prepare a polymerizable monomer composition, and the polymerizable monomer composition is subjected to suspension polymerization. Thus, a method is known in which colored polymer particles containing a colorant are formed, and then the colored polymer particles are washed and dried. According to this polymerization method, without going through a grinding step,
A toner (colored polymer particles) can be obtained.

In this suspension polymerization method, in order to obtain fine colored polymer particles having a uniform particle size distribution, in addition to performing polymerization by uniformly dispersing a colorant or the like in a monomer,
It is important to carry out polymerization by uniformly and stably suspending particles (droplets) of the polymerizable monomer composition in an aqueous medium. If the particles of the suspended polymerizable monomer composition are united or the particle size distribution of the particles is large, colored polymer particles having a uniform particle size distribution cannot be obtained.

Conventionally, various dispersion stabilizers have been added to suspension polymerization systems in order to uniformly and stably disperse the particles of the polymerizable monomer composition. Among these dispersion stabilizers, poorly water-soluble metal compounds such as calcium phosphate give colored polymer particles having a sharp particle size distribution, and are therefore used alone or in combination with other additives ( JP-A-63-198075, JP-A-4-12
No. 7162). After completion of the suspension polymerization, to remove the poorly water-soluble metal compound used as the dispersion stabilizer, washing is performed by adding an acid (acid washing), and then washing with water is performed sufficiently, followed by filtration, decantation, The colored polymer particles are collected by a suitable method such as centrifugation and dried to obtain a toner material. The polymerized toner thus obtained desirably has as little water content as possible in terms of image characteristics.

Conventionally, wet colored polymer particles obtained by a suspension polymerization method are generally dried using a spray drier, a fluidized drier, a tray type hot air drier or the like.
However, these dryers require a relatively high temperature and heat to evaporate the attached water and further reduce the amount of water in the particles, and as a result, thermal aggregation of the particles occurs during drying, There has been a problem that the sharp particle size distribution obtained in the polymerization step is widened, or the content of coarse particles is increased, and the image characteristics of the toner are deteriorated. Conventionally, when thermal aggregation of the colored polymer particles occurs in the drying step, the dried particles are classified by a classifier to remove coarse particles generated by the thermal aggregation, so that the particle size distribution becomes sharp. However, the yield in the classification process was poor, and it was not economical.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to produce a polymerized toner by a suspension polymerization method in an aqueous dispersion medium containing a poorly water-soluble metal compound as a dispersion stabilizer. Reduction and omission of the classification process are possible,
An object of the present invention is to provide a method for producing a polymerized toner by a more economical method, and externally adding an additive thereto to produce a toner for non-magnetic one-component development. Further, an object of the present invention relates to a non-magnetic one-component developing toner obtained by such a production method. The present inventor has conducted intensive studies to overcome the problems of the prior art, and as a result, drying the wet colored polymer particles obtained by the suspension polymerization method using a vacuum dryer, It has been found that the thermal energy at the time can be reduced and that a sharp particle size distribution obtained by polymerization can be maintained, and the present invention has been completed based on the findings.

[0008]

Thus, according to the present invention, a polymerizable monomer composition containing at least a polymerizable monomer and a colorant is converted into an aqueous dispersion medium containing a poorly water-soluble metal compound. After suspension polymerization in the color polymer particles is generated, an acid or an alkali is added to the suspension containing the color polymer particles to solubilize the poorly water-soluble metal compound in the aqueous dispersion medium. Then, washing and dehydration are performed, and the obtained wet colored polymer particles are dried in a vacuum drier, the particle size is not substantially changed from that before drying, and the heating weight loss method at 105 ° C. A process for recovering dry colored polymer particles having a water content of 0.21% or less, and externally adding an additive thereto.

According to the present invention, a polymerizable monomer composition containing at least a polymerizable monomer and a colorant is subjected to suspension polymerization in an aqueous dispersion medium containing a poorly water-soluble metal compound. An additive is externally added to the dried colored polymer particles having a water content of not more than 0.21% by a heating weight loss method at 105 ° C., which is obtained by vacuum drying the colored polymer particles obtained by the vacuum dryer. A non-magnetic one-component developing toner is provided.

Polymerizable monomer As the polymerizable monomer used in the present invention, a monomer having a vinyl group is preferably used. Specific examples of the polymerizable monomer include styrene monomers such as styrene, vinyltoluene and α-methylstyrene; acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, ethyl methacrylate, propyl methacrylate,
Acrylic acid or methacrylic acid such as butyl methacrylate, 2-ethylhexyl methacrylate, dimethylaminoethyl methacrylate, acrylonitrile, acrylamide and derivatives thereof; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl chloride; Vinyl halides such as vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl methyl ether;
Vinyl ethers such as vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone and methyl isopropenyl ketone; and vinyl monomers such as nitrogen-containing vinyl compounds such as 2-vinyl pyridine, 4-vinyl pyridine and N-vinyl pyrrolidone. These can be used alone or in combination of two or more.

Along with these vinyl monomers, crosslinking monomers such as aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and triethylene glycol dimethacrylate. Di-methacrylates such as methacrylate, trimethylolpropane triacrylate and 1,3-butanediol dimethacrylate
Or a tri-ethylenically unsaturated carboxylic acid ester;
Divinyl compounds such as N, N-divinylaniline, divinyl ether, divinyl sulfide, and divinyl sulfone, and compounds having three or more vinyl groups can be used alone or in combination of two or more. These crosslinkable monomers are usually used at a ratio of 0 to 20% by weight in all the polymerizable monomers including the vinyl monomer.

Colorant The colorant used in the present invention includes, for example, carbon black, aniline black, crystal violet, rhodamine B, malachite green, nigrosine,
Pigments and dyes such as copper phthalocyanine and azo dyes can be used alone or in combination of two or more. Metal oxides such as titanium oxide, silicon dioxide, and zinc oxide;
Magnetic powders such as iron, cobalt, nickel, iron sesquioxide, iron sesquioxide, iron manganese oxide, iron zinc oxide and nickel iron oxide can also be used as colorants. When toner particles having a particle size of about 2 to 50 μm are obtained using magnetic powder, it is preferable to use fine particles of about 1 μm or less.

Further, nigrosine dye, monoazo dye, metal-containing dye, zinc hexadecyl succinate, alkyl ester or alkyl amide of naphthoic acid, nitrohumic acid, N, N'-tetramethyldiaminebenzophenone, N, N'-tetramethyl Strongly polar substances called charge control agents in this field, such as benzene, triazine, and metal salicylate complexes, can be used alone or in combination of two or more. The amount of the colorant used is not particularly limited, and varies depending on the type thereof. However, the colorant is generally used in a proportion of about 0.1 to 200 parts by weight per 100 parts by weight of the polymerizable monomer. In the case of carbon black, about 1 to 20 parts by weight is sufficient.

The poorly water-soluble metal compound used as the dispersion stabilizer is, for example, calcium phosphate, magnesium phosphate, or the like.
Calcium sulfate, magnesium carbonate, calcium carbonate,
Calcium hydroxide, magnesium hydroxide, Ca ₃ (P
O ₄ ) _{2 and} other compounds exhibiting neutrality or alkalinity in water; aluminum phosphate, zinc phosphate, zinc carbonate and other compounds exhibiting acidity in water; and the like. These compounds can be used alone or in combination of two or more. In addition, poorly water-soluble metal compounds can be generated in situ. For example, reacting sodium phosphate and calcium chloride in water,
A poorly water-soluble metal compound can be produced and used as it is. The poorly water-soluble metal compound is used in an amount of usually 0.01 to 20 parts by weight, preferably 5 to 18 parts by weight, based on 100 parts by weight of the monomer component.

Production Method of Polymerized Toner The polymerized toner of the present invention is prepared by dissolving or dispersing a colorant and other additives in a polymerizable monomer to prepare a polymerizable monomer composition, and then preparing an oil-soluble polymerizable composition. It is obtained by suspension polymerization in an aqueous dispersion medium in the presence of an initiator, usually at a temperature of 30 to 200 ° C. In suspension polymerization,
As a dispersion stabilizer, a poorly water-soluble metal compound is used.

As the polymerization initiator, oil-soluble peroxide-based or azo-based initiators usually used for suspension polymerization can be used. Specifically, for example, benzoyl peroxide,
Peroxide initiators such as octanoyl peroxide, orthomethoxybenzoyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide and t-butyl hydroperoxide; 2,2'-azoisobutyronitrile, 2,2'- Azobis- (2,4-dimethylvaleronitrile), 2,2'-azobis-2,3-dimethylbutyronitrile, 2,2'-azobis-2,3,3-trimethylbutyronitrile, 2,2 ' Azo initiators such as -azobis-2-isopropylbutyronitrile, 4,4-azobis-4-cyanovaleric acid, and dimethyl-2,2'-azobisisobutyrate. The polymerization initiator is usually added to 100 parts by weight of the monomer component.
It is used in a proportion of 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight.

In the case of producing a polymerized toner by a suspension polymerization method, a polymerization initiator, a colorant and other additives (for example, a charge controlling agent) are added to the polymerizable monomer, and the mixture is stirred and mixed.
A polymerizable monomer composition is prepared. This polymerizable monomer composition is added to an aqueous dispersion medium to which a dispersion stabilizer has been added,
Stirring is performed so that the dispersed droplets of the polymerizable monomer composition fall within a desired particle size range. Next, the mixture is heated to a predetermined temperature, and polymerization is started under stirring. The polymerization temperature is usually about 50 to 70 ° C. The particle size (volume average particle size) of the toner obtained by suspension polymerization is generally 1 to 30 μm.
m, preferably about 5 to 20 μm.

After completion of the polymerization, an acid or an alkali is added to the system containing the produced colored polymer particles to make the poorly water-soluble metal compound soluble in the aqueous dispersion medium. An acid such as hydrochloric acid or an alkali such as sodium hydroxide is appropriately selected and used depending on the type of the poorly water-soluble metal compound. For example, when calcium phosphate is used as the poorly water-soluble metal compound, hydrochloric acid is added to make the pH of the system acidic, and calcium phosphate is converted to calcium chloride and solubilized in water.

After the poorly water-soluble metal compound is solubilized in the aqueous dispersion medium, washing is performed sufficiently to remove metal ions caused by the poorly water-soluble metal compound, and dehydration is performed. The wet colored polymer particles thus obtained are dried using a vacuum dryer. Spray dryers, fluidized dryers, and tray-type hot air dryers conventionally used for drying fine particles are used to dry the water adhering to the wet colored polymer particles (wet cake) after washing and dehydration, In addition, relatively high temperatures and thermal energy are required to reduce the amount of water in the particles. In addition, since the colored polymer particles have a property of thermal aggregation, drying using these dryers increases the proportion of coarse particles.

On the other hand, if a vacuum dryer is used,
At lower temperature and calorific value, the adhered moisture and moisture in the particles can be efficiently dried and removed (in Example 2, dried particles having a moisture content of 0.21%), and thermal aggregation of the particles during drying Can be prevented. Therefore, the heat energy at the time of drying can be reduced, and the classification step can be omitted. There are various types of vacuum dryers, and commercially available products include, for example, SV SV manufactured by Shinko Pantech Co., Ltd.
A mixer, especially a T series such as SV-001VT, or a blender dryer such as a conical blender dryer manufactured by Nippon Shokubai Co., Ltd., or a mixer type vacuum dryer can be mentioned as a preferable example.

Non-Magnetic One-Component Toner The polymerized toner obtained by the above-described method has a high image density under a normal temperature and normal humidity (23 ° C., 50% humidity) environment, and has a resolution free from fog and unevenness. Very good printing can be given. The polymerized toner obtained by the production method of the present invention can contain, for example, an additive for controlling chargeability, conductivity, or adhesion to a photoreceptor or a fixing roll, or can be externally added. . Examples of the additives include low molecular weight polyethylene, low molecular weight polypropylene, various waxes, release agents such as silicone oil, metal-containing dyes, dyes such as nigrosine dyes, and inorganic powders such as silica, cerium oxide, and zinc oxide. No. As a result, a toner applicable to the non-magnetic one-component developing method described in the examples is obtained.

[0022]

The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. In addition, parts and%
Are by weight unless otherwise specified.

[Example 1] Polymerizable monomer composition 83 parts styrene 17 parts butyl acrylate 17 parts carbon black 5 parts (Printex 150T, manufactured by Degussa) 1 part of charge control agent (Spiron Black TRH, manufactured by Hodogaya Chemical Co., Ltd.) ) Divinylbenzene 0.3 part 2,2'-azobisisobutyronitrile 2 parts The above components were rotated at 6,000 rpm by a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) which is a mixer having a high shearing force. The resulting mixture was stirred and mixed to prepare a uniformly dispersed polymerizable monomer composition. Next, 15 parts of calcium phosphate (manufactured by Wako Pure Chemical Industries, Ltd.) is dispersed in an aqueous solution obtained by dissolving 0.01 part of sodium dodecylbenzenesulfonate (DBS) in 250 parts of ion-exchanged water to obtain a dispersion containing a polymerization stabilizer. (Aqueous dispersion medium) was prepared. Next, the polymerizable monomer composition is added to the dispersion of the polymerization stabilizer obtained above, and the mixture is stirred at 10,000 rpm with a TK homomixer at a high shear to obtain a polymerizable monomer composition. Droplets (polymerized monomer composition particles) were granulated. This granulated aqueous dispersion of the polymerizable monomer composition is placed in a reactor equipped with a stirring blade, and
The polymerization reaction was carried out by stirring at 5 ° C. for 8 hours to obtain an aqueous dispersion of colored polymer particles (polymerized toner particles).

The particle diameter of the polymerized toner particles after the completion of the polymerization reaction was measured with a Coulter counter (manufactured by Coulter Co.), and the volume average particle size (dv) was 8.82 μm.
The number average particle size (dp) was 6.73 μm, and the particle size distribution, that is, the ratio (dv / dp) between the volume average particle size and the number average particle size (dp) was 1.31. In addition, particles having a volume particle size of 20 μm or more accounted for 0.31%, and particles having a number particle size of 5 μm or less accounted for 15.8%. In the measurement by the Coulter counter, the following parameters were used. Aperture diameter: 100 μm Medium: Isoton II Concentration: 15% Number of measured particles: 50,000

Next, while stirring the aqueous dispersion obtained above, hydrochloric acid was added to adjust the pH of the system to 4 or less, and calcium phosphate, a poorly water-soluble metal compound used as a dispersion stabilizer, was converted into calcium chloride. And solubilized in water. The slurry of the polymerized toner particles was dehydrated and washed to obtain a wet cake of the polymerized toner. Next, the wet cake of the polymerized toner obtained above was applied to a 100-liter SV mixer type vacuum dryer (manufactured by Shinko Pantech Co., Ltd.).
It was dried for 4 hours under the conditions of a wet cake preparation amount of 40 kg, a temperature of 50 ° C. and a degree of vacuum of 20 to 30 Torr using a trade name of SV-001VT. The water content of the dried toner at 105 ° C. measured by a weight loss method was 0.13%.

The particle diameter of the polymerized toner after drying has a volume average particle diameter (dv) of 8.90 μm, a number average particle diameter (dp) of 6.79 μm, and a particle diameter distribution (dv / dp) of 1.90 μm. 3
It was one. In addition, particles having a volume particle size of 20 μm or more have a particle diameter of 0.
The ratio of particles having a particle size of 45% and a particle diameter of 5 μm or less was 15.1%, which was not substantially changed from that before drying. To 100 parts of the polymerized toner particles obtained above, 0.5 part of colloidal silica (trade name: R-202, manufactured by Nippon Aerosil Co., Ltd.) was added and mixed with a Henschel mixer to prepare a toner. . Using the toner thus obtained, printing evaluation was performed by a commercially available non-magnetic one-component developing system printer under the environment of normal temperature and normal humidity at a temperature of 23% and a humidity of 50%, and the image density was high. Very good printing with no fog or unevenness in resolution was obtained.

Example 2 A polymerizable monomer composition was obtained in the same manner as in Example 1 except that the vacuum dryer SV-001VT was replaced with a conical blender dryer (manufactured by Nippon Dryer Co., Ltd.). The product was polymerized, washed with acid, washed with water, dehydrated, and dried to prepare a polymerized toner. The conditions for drying with a conical dryer at this time are as follows. Model: CBD-300 Capacity: 300 liters Charge: 120 kg Temperature: 50 ° C. Vacuum: 20-30 Torr Drying time: 5 hours

The water content of the dried toner at 105 ° C. by the weight loss method was 0.21%. The volume average particle diameter (dv) of the polymerized toner before drying is 9.2.
2 μm, the number average particle diameter (dp) is 6.84 μm,
The particle size distribution (dv / dp) was 1.35. In addition, 0.51% of particles having a volume particle diameter of 20 μm or more and a number particle diameter of 5 μm.
m or less were 13.7%. As for the particle diameter of the polymerized toner after drying, the volume average particle diameter (dv) was 9.13 μm, the number average particle diameter (dp) was 6.91 μm, and the particle diameter distribution (dv / dp) was 1.33. Was. In addition, volume particle size 2
The particles having a particle size of 0 μm or more were 0.62%, and the particles having a number particle size of 5 μm or less were 12.8%, which was not substantially changed from that before drying.

In the same manner as in Example 1, a toner was prepared by mixing the polymerized toner particles with colloidal silica subjected to hydrophobic treatment. When printing was evaluated using the toner described above in the same manner as in Example 1, clear printing was obtained with high image density and no fog or unevenness.

Example 3 A polymerizable monomer composition was prepared in the same manner as in Example 1 except that the amount of calcium phosphate used for preparing the dispersion of the polymerization stabilizer was changed to 25 parts. The product was polymerized, washed with acid, washed with water, dehydrated, and dried to obtain a polymerized toner. Drying conditions are the same as in Example 1. The water content of the obtained dried toner at 105 ° C. by a heating loss method was 0.15%. The volume average particle diameter (dv) of the polymerized toner before drying is 6.8.
5 μm, the number average particle diameter (dp) is 5.07 μm,
The particle size distribution (dv / dp) was 1.35. 0.83% of the particles having a volume particle size of 16 μm or more have a number particle size of 5 μm.
24.8% of particles having a particle size of μm or less were used. The average particle diameter (dv) of the polymerized toner after drying was 7.01 μm,
The number average particle size (dp) was 5.16 μm, and the particle size distribution (dv / dp) was 1.36. In addition, volume particle size 1
1.32% of the particles having a particle diameter of 6 μm or more and 26.3% of the particles having a particle diameter of 5 μm or less were substantially unchanged from those before drying.

In the same manner as in Example 1, a toner was prepared by mixing the polymerized toner particles with colloidal silica subjected to a hydrophobic treatment. When printing was evaluated using the toner described above in the same manner as in Example 1, clear printing was obtained with high image density and no fog or unevenness.

Comparative Example 1 The procedure of Example 1 was repeated, except that a fluidized medium dryer (manufactured by Okawara Seisakusho Co., Ltd.) was used as the dryer. Water washing and dehydration were performed to obtain a wet cake. The wet cake was reslurried in water at a solid content of 30% and supplied to a fluidized medium dryer. The drying conditions at this time are as follows. Model: SFD-0.4 type Ball: Alumina, 2mmφ, 7kg Blowing temperature: 60 ° C Supply amount: 5.3kg / h Wind speed: 3.4m / s

The water content of the dried toner at 105 ° C. measured by a weight loss method was 0.35%. As for the particle diameter of the polymerized toner before drying, the volume average particle diameter (dv) is 8.8.
5 μm, the number average particle diameter (dp) is 6.65 μm,
The particle size distribution (dv / dp) was 1.33. In addition, particles having a volume particle size of 20 μm or more account for 0.43% and a number particle size of 5 μm.
14.8% or less of particles having a size of μm or less. The particle diameter of the polymerized toner after drying is 9.91 μm in volume average particle diameter (dv),
The number average particle size (dp) was 7.74 μm, and the particle size distribution (dv / dp) was 1.28. In addition, volume particle size 2
The particles having a particle size of 0 μm or more are 5.47%, and the particles having a number particle size of 5 μm or less are 10.3%.
The above coarse particles increased.

In the same manner as in Example 1, a toner was prepared by mixing the polymerized toner particles with colloidal silica subjected to a hydrophobic treatment. When printing was evaluated in the same manner as in Example 1 using the above toner, fog was large, reproducibility of fine lines was poor, and printing that could be used practically could not be obtained.
The dried polymerized toner was classified with a classifier DS-II manufactured by Nippon Pneumatic Co., Ltd. to have a volume average particle size (dv) of 9.02 μm, a number average particle size (dp) of 6.94 μm,
The particle size distribution (dv / dp) was 1.30. The particles having a volume particle size of 20 μm or more were 0%, and the particles having a number particle size of 5 μm or less were 13.7%. The product yield at this classification is 8
6.4%.

In the same manner as in Example 1, the polymerized toner particles were mixed with a hydrophobically treated colloidal silica to prepare a toner. When printing was evaluated in the same manner as in Example 1 using the toner described above, clear printing was obtained with high image density, no fog and unevenness, and good reproducibility of fine lines.

Comparative Example 2 Example 1 was the same as Example 1 except that a mobile minor type spray dryer (manufactured by Ashizawa Niro Atomizer) was used as the dryer.
In the same manner as described above, polymerization of the monomer composition, acid washing, water washing,
Dehydration was performed to obtain a wet cake. This wet cake was reslurried in water at a solid content of 15% and supplied to a spray dryer. The drying conditions at this time were as follows. Model: Mobile minor type (MM type) Wheel diameter: 50 mmφ Number of rotations: 30,000 rpm Blowing temperature: 200 ° C. Air volume: 17 Nm ³ / h Supply amount: 3.5 kg / h

The water content of the dried toner at 105 ° C. by a weight loss method was 0.57%. As for the particle diameter of the polymerized toner before drying, the volume average particle diameter (dv) is 8.8.
5 μm, the number average particle diameter (dp) is 6.65 μm,
The particle size distribution (dv / dp) was 1.33. In addition, particles having a volume particle size of 20 μm or more account for 0.43% and a number particle size of 5 μm.
14.8% or less of particles having a size of μm or less. The volume average particle diameter (dv) of the polymerized toner after drying is 10.73 μm.
m, the number average particle size (dp) was 8.58 μm, and the particle size distribution (dv / dp) was 1.25. 8.37% of the particles having a volume particle diameter of 20 μm or more have a number particle diameter of 5 μm.
The following particles are 8.3%, 20 μm compared to before drying.
m or more coarse particles increased.

A toner was prepared by mixing the polymerized toner particles with colloidal silica subjected to hydrophobic treatment in the same manner as in Example 1. When printing was evaluated in the same manner as in Example 1 using the above toner, fog was large, reproducibility of fine lines was poor, and printing that could be used practically could not be obtained.
The dried polymerized toner was classified with a classifier DS-II manufactured by Nippon Pneumatic Co., Ltd. to have a volume average particle size (dv) of 9.58 μm, a number average particle size (dp) of 7.79 μm,
The particle size distribution (dv / dp) was set to 1.23. The particles having a volume particle diameter of 20 μm or more accounted for 0%, and the particles having a number particle diameter of 5 μm or less accounted for 10.1%. The product yield at the time of this classification was 80.5%.

As in Example 1, the toner particles were mixed with colloidal silica subjected to a hydrophobic treatment to prepare a toner. When the printing evaluation was performed using the above toner in the same manner as in Example 1, clear printing was obtained with high image density and good reproducibility of fine lines without fog and unevenness.

[0040]

According to the present invention, when a polymerized toner is produced by a suspension polymerization method in an aqueous dispersion medium containing a sparingly water-soluble metal compound as a dispersion stabilizer, the reduction of heat energy during drying and the classification step Can be omitted, a polymerized toner can be produced more economically, and a toner for non-magnetic one-component development is provided by externally adding an additive thereto.

Claims (4)

[Claims] Claims: 1. A polymerizable monomer composition containing at least a polymerizable monomer and a colorant is subjected to suspension polymerization in an aqueous dispersion medium containing a poorly water-soluble metal compound to produce colored polymer particles. Is generated, an acid or an alkali is added to the suspension containing the colored polymer particles to solubilize the poorly water-soluble metal compound in the aqueous dispersion medium, followed by washing and dehydration to obtain the obtained wet. The colored polymer particles are dried by a vacuum dryer, and the particle size is not substantially changed from that before drying, and the water content by a heating loss method at 105 ° C. is 0.21% or less. A method for producing a non-magnetic one-component developing toner, comprising collecting colored polymer particles and externally adding an additive thereto. 2. The method according to claim 1, wherein the aqueous dispersion medium containing the poorly water-soluble metal compound is an aqueous dispersion medium containing the hardly water-soluble metal compound generated in situ. 3. The method according to claim 1, wherein the vacuum dryer is a blender dryer or a mixer type vacuum dryer. 4. A colored polymer obtained by suspension-polymerizing a polymerizable monomer composition containing at least a polymerizable monomer and a colorant in an aqueous dispersion medium containing a poorly water-soluble metal compound. For non-magnetic one-component development, an additive is externally added to a dry colored polymer particle having a water content of 0.21% or less by a heating loss method at 105 ° C., which is obtained by vacuum drying a particle in a vacuum dryer. toner.