JP2001235903A - Toner and method of manufacturing toner with unintentional addition of fluidity imparting agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing toner with unintentional addition of a fluidity imparting agent, the method which is economically advantageous because the toner can be produced by an easy method and by which the fluidity imparting agent can be uniformly deposited on the toner particles, and to provide the toner produced by that method. SOLUTION: The method of manufacturing the toner with unintentional addition of a fluidity imparting agent includes a process of mixing a water-based dispersion liquid of polymerized toner prepared by suspension polymerization of polymerizable monomer in a water medium and a dispersion liquid prepared by dispersing a fluidity imparting agent in a medium, and a process of removing the water-based medium used for the suspension polymerization and of removing the medium used for the dispersion of the fluidity imparting agent from the obtained mixture liquid so as to obtain the toner with unintentional addition of the fluidity imparting agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used for developing an electrostatic image in an electrophotographic method, an electrostatic recording method or the like, and a method for producing a toner to which a fluidity-imparting agent is externally added.

[0002]

2. Description of the Related Art Conventionally, a toner used for the purpose of electrophotography generally melts and mixes a coloring agent composed of a dye and a pigment in a thermoplastic resin and uniformly disperses the same. Toners having a diameter have been manufactured.

On the other hand, Japanese Patent Publication Nos. 36-10231, 43-10799 and 51-14895 propose a method for producing a toner by a suspension polymerization method. In the suspension polymerization method, a polymerizable monomer, a colorant, a polymerization initiator, and, if necessary, a crosslinking agent, a charge control agent, and other additives are uniformly dissolved or dispersed to form a monomer composition. Thereafter, the monomer composition was dispersed in a continuous phase containing a dispersion stabilizer, for example, an aqueous phase using a suitable stirrer, and simultaneously subjected to a polymerization reaction to prepare toner particles having a desired particle size. Thereafter, the aqueous medium is removed, washed with water, and dried to obtain toner particles.

Since this method does not include any pulverizing step, the toner does not need to be brittle, a soft material can be used, and energy can be saved because the classification step can be omitted. The cost reduction effect is large, such as shortening the time and improving the process yield. Further, there is an advantage that a colorant is not exposed to the particle surface and uniform triboelectricity is obtained.

[0005] Further, a fluidity-imparting agent is usually externally added to the toner in order to enhance fluidity, anti-caking property, fixing property and cleaning property. As the fluidity-imparting agent, various ones in which the surface of inorganic fine particles is subjected to a hydrophobizing treatment in order to improve dispersibility have been proposed (JP-A-46-5782, JP-A-48-4).
7345, JP-A-48-47346). The method of external addition is performed dry,
Specifically, it is performed by mixing toner particles and a fluidity-imparting agent.

However, in the case of dry mixing, a special mixing device is required, and it is difficult to uniformly attach a fluidity-imparting agent to toner particles, and it is not possible to impart desired characteristics to the toner. Further, when the fluidity-imparting agent is silica manufactured by a wet method, there is the complexity that the steps of removing the medium, washing with water, and drying are required twice in both the toner manufacturing and the silica manufacturing, and are economical. Is also disadvantageous. Furthermore, in the case of silica produced by a wet method using an organic solvent, a special and expensive dryer must be used due to safety issues in order to remove and dry the organic solvent, which is economically disadvantageous. is there.

Further, when an organic photoreceptor is used to achieve higher image quality or a toner having a smaller particle size is used, sufficient performance cannot be obtained by using the above-mentioned inorganic fine particles. I have. The organic photoreceptor has a softer surface and higher reactivity than the inorganic photoreceptor, so that its life is likely to be shorter. Therefore, when such an organic photoreceptor is used, the photoreceptor is likely to be deteriorated or scraped by the inorganic fine particles added to the toner. In addition, when the toner has a small particle size, the powder fluidity is lower than that of a toner having a commonly used particle size, so that a larger amount of inorganic fine particles must be used. May cause toner to adhere to the photoreceptor.

[0008]

The object of the present invention is to provide an economical advantage because it can be manufactured by a simple method.
An object of the present invention is to provide a method for producing a toner to which a fluidity-imparting agent capable of uniformly attaching a fluidity-imparting agent to toner particles is externally added, and to provide such toner. In addition, the object of the present invention is that there is no reaction or interaction with the organic photoreceptor, so that the photoreceptor does not cause deterioration or cracking, and because the fluidity is good, toner does not adhere to the photoreceptor. A toner to which a fluidity-imparting agent is externally added, and a method for producing the toner.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a polymerized toner aqueous dispersion obtained by suspension polymerizing a polymerizable monomer in an aqueous medium. And a step of mixing the fluidity-imparting agent with the dispersion liquid dispersed in the medium, and the aqueous medium used for the suspension polymerization and the medium used to disperse the fluidity-imparting agent from the obtained mixture. It has been found that a method for producing a toner externally added with a fluidity-imparting agent solves this problem, comprising a step of obtaining a toner externally added with a fluidity-imparting agent by removing the toner.

Further, the present invention comprises a polymerized toner and a fluidity-imparting agent externally added to the polymerized toner, wherein the fluidity-imparting agent has the following conditions (i) and (ii): It is intended to provide a toner characterized by being spherical hydrophobic silica fine particles having an average primary particle size of 0.01 to 5 μm satisfying the following. (i) When an organic compound which is liquid at room temperature and has a dielectric constant of 1 to 40 F / m and silica fine particles are mixed at a weight ratio of 5: 1 and shaken, the silica fine particles are contained in the organic compound. Disperse evenly. (ii) After evaporating methanol from a dispersion of the silica fine particles in methanol by heating with an evaporator, 100
When kept at a temperature of ° C for 2 hours, it remains as primary particles
The ratio of the primary particle amount to the initially existing primary particle amount is 20%
That is all.

This toner can be obtained by using the above-mentioned hydrophobic silica fine particles as a fluidity imparting agent in the above-mentioned production method. The hydrophobic silica fine particles have a highly hydrophobic surface and no reactive groups such as silanol groups remain, and also have high dispersibility, low cohesion and good fluidity, so that the objects and effects of the present invention can be achieved. It gives good results.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the toner production method of the present invention, first, a polymerization toner aqueous dispersion and a fluidity imparting agent dispersion are mixed. -Preparation of fluidity imparting agent aqueous dispersion-What is suitable as a fluidity imparting agent used in the present invention,
Spherical hydrophobic silica fine particles satisfying the above conditions (i) and (ii) and having an average primary particle size of 0.01 to 5 μm. Two types of such hydrophobic silica fine particles can be exemplified.

-Hydrophobic silica fine particles A: one of which is Si
O ₂ R ¹ to hydrophilic silica fine particle surface comprising a unit ₃ SiO _1/2 units (wherein, R ¹ is the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms) introducing The resulting particles are spherical hydrophobic silica fine particles having an average particle diameter of 0.01 to 5 μm (hereinafter referred to as hydrophobic silica fine particles A).

One example of a method for producing the hydrophobic silica fine particles A is as follows. A tetrafunctional silane represented by the general formula (I): Si (OR ³ ) ₄ (I) (where R ³ is the same or different, substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms) One or two selected from compounds or hydrolysates thereof
Obtaining a dispersion of hydrophilic silica fine particles by hydrolyzing and condensing at least one compound in a mixed solution of a hydrophilic solvent such as methanol or ethanol, water and a basic compound such as ammonia or an organic amine; hydrophilic silica fine particle dispersion in general formula _{^{(II): R 1 3 SiNHSiR}} 1 3 (II) ( where, R ¹ represents the same or a monovalent hydrocarbon group having 1 to 6 carbon atoms heterologous) silazane represented by A compound represented by the general formula (II
_{^{I): R 1 3 SiX (}} III) ( where, R ¹ is the general formula (II) are as defined, X is added a compound selected from silane compounds represented by the OH group or a hydrolyzable group) Reacting the silanol groups present on the surface of the silica fine particles by trialkylsilylation to hydrophobize them.

Hydrophobic silica fine particles B: Another example of the hydrophobic silica fine particles (hereinafter referred to as hydrophobic silica fine particles B) is that the surface of the hydrophilic silica fine particles composed of SiO ₂ units has R ² particles.
SiO _3/2 (where R ² is a monovalent hydrocarbon group having 1 to 20 carbon atoms)
Was hydrophobic silica fine particle surface in R ¹ ₃ SiO _1/2 units obtained by introducing a (wherein, R ¹ is a monovalent hydrocarbon group having 1 to 6 carbon atoms of the same or different) obtained by introducing The resulting particles are spherical hydrophobic silica fine particles having an average particle diameter of 0.01 to 5 μm.

One example of a method for producing the hydrophobic silica fine particles B is as follows. A tetrafunctional silane compound represented by the general formula (I), that is, Si (OR ³ ) ₄ (I) (where R ³ is the same or different, a monovalent hydrocarbon group having 1 to 6 carbon atoms) or One or more compounds selected from the hydrolyzate are hydrolyzed and condensed in a mixed solution of a hydrophilic solvent such as methanol or ethanol, water and a basic compound such as ammonia or an organic amine, and condensed. A step of obtaining a dispersion of hydrophilic silica fine particles; a step of adding water to the obtained dispersion of hydrophilic silica fine particles, distilling off the hydrophilic solvent, converting the dispersion into an aqueous dispersion, and completely hydrolyzing the alkoxy groups remaining on the surface of the fine particles. The hydrophilic silica fine particle aqueous dispersion thus obtained is added to a general formula (IV): R ² Si (OR ⁴ ) ₃ (IV) (where R ² is a monovalent hydrocarbon group having 1 to 20 carbon atoms, R ⁴ is the same or different monofunctional hydrocarbon group having 1 to 6 carbon atoms) Adding one or more compounds selected from a hydrophilic silane compound and a hydrolyzate thereof, and treating the surface of the hydrophilic silica fine particles with the compound to obtain hydrophobic silica fine particles; A step of adding a ketone-based solvent to the aqueous silica fine particle dispersion and distilling off water to convert it to a hydrophobic silica fine-particle ketone-based solvent dispersion,
The hydrophobic silica fine particle ketone-based solvent dispersion has the general formula
(II), _{^{i.e., R 1 3 SiNHSiR 1 3 (}} II) ( where, R ^l may be the same or a monovalent hydrocarbon group having 1 to 6 carbon atoms heterologous) silazane compound represented by, and the general formula
(III), _{^{i.e., R 1 3 SiX (III)}} ( where, R ¹ is as defined for formula (II), X is
(OH group or hydrolyzable group) Production of hydrophobic silica fine particles having a process of adding and reacting a compound selected from silane compounds represented by the formula (III) to trialkylsilyl the silanol groups remaining on the surface of the silica fine particles and further highly hydrophobizing them. Is the way.

The raw materials used in the above manufacturing method will be described in detail as follows. First, those commonly used for producing the hydrophobic silica fine particles A and B will be described.

First, specific examples of the tetrafunctional silane compound represented by the general formula (I) include alkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, and tetrabutoxysilane.
Specific examples of the partially hydrolyzed condensate of the tetrafunctional silane compound represented by the general formula (I) include methyl silicate,
Ethyl silicate and the like can be mentioned.

The hydrophilic organic solvent is not particularly limited as long as it can dissolve the compound of the formula (I) or its partially hydrolyzed condensate and water. Examples thereof include alcohols, methyl cellosolve, ethyl cellosolve, butyl cellosolve and cellosolve acetate. And ketones such as acetone and methyl ethyl ketone, and ethers such as dioxane and tetrahydrofuran. Alcohols are preferable. Examples of the alcohol include an alcohol solvent represented by the general formula (V): R ⁵ OH (V) (where R ⁵ is a monovalent hydrocarbon group having 1 to 6 carbon atoms). Examples include methanol, ethanol, isopropanol, butanol and the like. As the number of carbon atoms in the alcohol increases, the particle size of the silica fine particles formed increases. Therefore, it is desirable to select the type of alcohol according to the target particle size of the silica fine particles.

Examples of the basic compound include ammonia, dimethylamine, diethylamine and the like, and ammonia is preferred. After dissolving a required amount of these basic compounds in water, the resulting aqueous solution (basic water) may be mixed with a hydrophilic organic solvent.

The amount of water used at this time is determined by the general formula (I)
Is preferably 0.5 to 5 mol per 1 mol of the alkoxy group of the silane compound or the partial hydrolysis condensate thereof, and the ratio of water / hydrophilic organic solvent is preferably 0.5 to 10 by weight, and The amount of the hydrophilic compound is preferably 0.01 to 1 mol per 1 mol of the alkoxy group of the silane compound of the general formula (I) or the partial hydrolysis condensate thereof.

Specific examples of the silazane compound represented by the general formula (II) include hexamethyldisilazane. Specific examples of the monofunctional silane compound represented by the general formula (III) include trimethylsilanol and triethylsilanol. Monosilanol compounds such as silanol, trimethylchlorosilane, monochlorosilane such as triethylchlorosilane, trimethylmethoxysilane, monoalkoxysilane such as trimethylethoxysilane, trimethylsilyldimethylamine,
Monoaminosilane such as trimethylsilyldiethylamine and monoacyloxysilane such as trimethylacetoxysilane are exemplified.

The amount of these used is 0.1 to 0.5 mole, preferably 0.2 to 0.3 mole, per mole of SiO ₂ unit of the hydrophilic silica fine particles used.

For the hydrolysis and condensation of the tetrafunctional silane compound of the general formula (I), the tetrafunctional silane compound of the general formula (I) is dropped into a mixture of water and a hydrophilic organic solvent containing a basic compound. This is performed by a known method. The conversion of the dispersion medium of the silica fine particle mixed solution dispersion into water can be performed, for example, by an operation of adding water to the dispersion and distilling off the hydrophilic organic solvent (this operation is repeated as necessary). . The amount of water added at this time is 0.5 to 2 times by weight, and preferably about 1 time by weight, based on the total amount of the hydrophilic organic solvent used and the generated alcohol.

The trifunctional silane compound represented by the general formula (IV) is used in a method for producing hydrophobic silica fine particles B. Specific examples thereof include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane,
Trialkoxysilanes such as i-propyltrimethoxysilane, i-propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, and the like. Good.

The amount of the trifunctional silane compound represented by the general formula (IV) is from 1 to 0.01 mol, preferably from 0.1 to 0.01 mol, per 1 mol of SiO ₂ unit of the hydrophilic silica fine particles used. Is good.

In the step of converting the dispersion medium of the aqueous dispersion of hydrophobic silica fine particles into a ketone-based solvent, an operation of adding a ketone-based solvent to the dispersion and distilling off water (repeatedly, if necessary) is performed. Will be

The amount of the ketone solvent added at this time is 0.5 to 5 times, preferably 1 to 2 times the weight ratio of the hydrophilic silica fine particles used. Specific examples of the ketone solvent used here include methyl ethyl ketone, methyl isobutyl ketone, acetylacetone and the like, and preferably methyl isobutyl ketone.

The particle diameter of the hydrophobic silica fine particles is preferably 0.01 to 5 μm, and more preferably 0.05 to 5 μm, from the viewpoint of improving the fluidity, anti-caking property and fixing property of the developer and reducing the adverse effect on the photoreceptor. 0.5 μm. Particle size is 0.01μ
If the particle size is smaller than m, the fluidity, caking resistance and fixing property of the developer cannot be obtained due to aggregation, and if the particle size exceeds 5 μm, disadvantages such as denaturation of the photoreceptor, shaving, and reduced adhesion to the toner occur.

In the present invention, such hydrophobic silica fine particles A, B and other fluidity-imparting agents are dispersed in a medium to prepare a fluidity-imparting agent dispersion.

The medium used as the dispersion medium is not particularly limited as long as it does not deteriorate the polymerized toner when mixed with the polymerized toner aqueous medium. For example, the hydrophilic organic solvent used in the production of the hydrophobic silica fine particles, water,
When a ketone-based organic solvent or the like can be used, and the above-described hydrophobic silica fine particles A and B are used as a fluidity imparting agent,
The dispersion of hydrophobic silica fine particles obtained by the production thereof may be used as it is. Other media may be added as needed.

-Preparation of Polymerized Toner Aqueous Dispersion- The polymerized toner aqueous dispersion used in the present invention is obtained by suspension polymerizing a polymerizable monomer in an aqueous medium. More specifically, it is obtained by the following method. That is, a mold release agent, a colorant, a charge control agent, and other additives are added to the polymerizable monomer in addition to the usual colorant and polymerization initiator as necessary, and the mixture is uniformly mixed with a homogenizer, an ultrasonic disperser, or the like. Dissolve or disperse the monomer system in an aqueous medium containing a dispersion stabilizing agent using a conventional stirrer or homomixer.
Disperse with a homogenizer or the like. Preferably, the granulation is performed by adjusting the stirring speed and time so that the monomer droplets have a desired toner particle size, generally a particle size of 30 μm or less. After that, by the action of the dispersion stabilizer, stirring may be performed to such an extent that the particle state is maintained and the particles are prevented from settling or floating. Polymerization reaction is 40 ° C or higher, generally 50-90 ° C
The polymerization is carried out at the same temperature, and the polymerization-based toner aqueous medium is obtained upon completion of the polymerization.

Examples of the polymerizable monomer include styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, and p-ethylstyrene; methyl acrylate; Ethyl acid,
Acrylic esters such as n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate , Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, Examples include methacrylates such as dimethylaminoethyl methacrylate and ethylaminoethyl methacrylate, and monomers such as acrylonitrile, methacrylonitrile, and acrylamide.

These monomers can be used alone or in combination of two or more. Among the above-mentioned monomers, it is preferable to use styrene or a styrene derivative alone or in a mixture with another monomer, from the viewpoint of the developing characteristics and durability of the toner.

As the polymerization initiator, any suitable polymerization initiator, for example, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile,
1'-azobis (cyclohexa-1-carbonitrile),
Azo or diazo polymerization initiators such as 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, Peroxide polymerization initiators such as 2,4-dichlorobenzoyl peroxide and lauroyl peroxide are exemplified. These polymerization initiators are preferably added in an amount of 0.5 to 20% by weight of the polymerizable monomer.

As the colorant, known ones can be used as long as they do not inhibit polymerization or transfer to an aqueous phase, and examples thereof include carbon black, iron black, dyes and pigments. These are preferably used after being subjected to a hydrophobic surface treatment.

The release agent is added for the purpose of improving the releasability during hot roll fixing when the obtained toner is actually used. Particularly well-known waxes such as hydrocarbon-based compounds usually added as a release agent to the toner are exemplified.

The charge control agent is added for the purpose of controlling the chargeability of the toner. As the charge control agent, a known charge control agent can be used as long as it has little polymerization inhibitory property and water phase transfer property.

Further, a magnetic substance may be added. This is preferably used after performing a hydrophobic surface treatment.

Examples of the dispersion stabilizer include inorganic compounds such as calcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, and metasilicate. Examples include calcium, calcium sulfate, barium sulfate, bentonite, silica, alumina and the like. Examples of the organic compound include polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salts of carboxymethylcellulose, polyacrylic acid and salts thereof, and starch. This dispersion stabilizer is preferably used in an amount of 0.2 to 20 parts by weight based on 100 parts of the polymerizable monomer.

For fine dispersion of the dispersion stabilizer, 0.001 to 0.1 parts by weight of a surfactant may be used. This is to promote the intended action of the dispersion stabilizer, and specific examples thereof include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, and sodium laurate. , Potassium stearate, calcium oleate and the like.

When an inorganic compound is used among these dispersion stabilizers, a commercially available one may be used as it is, but in order to obtain finer particles, the inorganic compound may be formed in an aqueous medium. For example, in the case of calcium phosphate, an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride may be mixed under high stirring.

-Production of Toner- According to the method of the present invention, the polymerized toner dispersion prepared as described above and the aqueous dispersion of the fluidity-imparting agent are first mixed, and the fluidity-imparting agent is added to the polymerized toner. To adhere. The mixing may be a stirring simply to the extent that the two media are mixed, or a stirring with a shearing force applied to such an extent that the toner and the fluidity-imparting agent are not destroyed.

The state of adhesion of the fluidity-imparting agent to the surface of the toner particles may be merely mechanical adhesion, or may be loosely fixed to the surface. Further, the toner particles may cover the entire surface or a part of the toner particles. Further, the fluidity-imparting agent may be coated as a part of aggregate, but is preferably coated in a single-layer particle state.

The mixing ratio of the aqueous dispersion of the polymerized toner and the dispersion of the fluidity-imparting agent depends on the solid content of each polymer. The amount is preferably 1 to 20 parts by weight, more preferably 0.1 to 5 parts by weight. If the amount is too small, the amount of the fluidity-imparting agent attached to the polymerization method toner is too small to obtain sufficient fluidity, and if the amount is too large, not only adversely affects the chargeability of the obtained toner but also economically. Is also disadvantageous.

Next, the aqueous medium which was the dispersion medium of the aqueous dispersion of the polymerization toner and the medium used for dispersing the fluidity-imparting agent are removed. This step is performed, for example, by filtration or heat distillation. Of these, filtration is more economically preferred. Further, if necessary, after washing with water in order to remove the dispersion stabilizer and the like, the polymerized toner externally added with a fluidity-imparting agent can be obtained by drying.

As described above, according to the method of the present invention, the mixing of the polymerizable toner and the fluidity-imparting agent is performed in a slurry state, and therefore, unlike the case of the dry mixing, a special mixing device is not required. Further, the fluidity-imparting agent can be easily and uniformly attached to the particles of the polymerization toner, and desired characteristics can be imparted to the obtained toner.

When the above-mentioned hydrophobic silica fine particles are used as the fluidity-imparting agent, the fluidity-imparting agent is produced by a wet method. Therefore, in both toner production and silica production, removal of the medium, washing with water, Process such as drying
There is no duplication, technical complexity can be avoided, and it is economically advantageous. In particular, in the case of silica produced by a wet method using an organic solvent, there is no need to use a special and expensive dryer for removing and drying the organic solvent, which is economically advantageous.

Further, if necessary, additives for the purpose of imparting various properties may be added later to the mixture of the aqueous dispersion of the polymerization toner and the dispersion of the fluidity-imparting agent, or the obtained additive may be obtained. The fluidity-imparting agent may be added later to the externally added toner. Examples of such additives that can be added later include the following.

As the fluidity-imparting agent, for example, a metal oxide
(Silicon oxide, aluminum oxide, titanium oxide, and the like), carbon black, carbon fluoride, and the like, each of which is preferably subjected to a hydrophobic treatment.

As an abrasive, for example, metal oxides (strontium titanate, cerium oxide, aluminum oxide,
Examples thereof include magnesium oxide and chromium oxide, nitrides (such as silicon nitride), carbides (such as silicon carbide), and metal salts (such as calcium sulfate, barium sulfate, and calcium carbonate).

As the lubricant, for example, fluorine resin powder
(Vinylidene fluoride, polytetrafluoroethylene, etc.) and fatty acid metal salts (zinc stearate, calcium stearate, etc.).

Examples of the charge control particles include metal oxides (tin oxide, titanium oxide, zinc oxide, silicon oxide, aluminum oxide, etc.), carbon black and the like.

These additives may be used alone or in combination of two or more. These post-added additives are preferably used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the polymerization toner particles, and particularly preferably 0.1 to 10 parts by weight.
Used up to 5 parts by weight.

[0055]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. Parts mean parts by weight unless otherwise specified. Example 1 I. [Synthesis of Spherical Hydrophobic Silica Fine Particle Dispersion Medium] 693.0 g of methanol, 46.0 g of water, and 55.3 g of 28% aqueous ammonia were added to a 3-liter glass reactor equipped with a stirrer, a dropping funnel, and a thermometer. And mixed. 1293.0 g (8.5 mol) of tetramethoxysilane and 464.5 g of 5.4% aqueous ammonia were simultaneously added to the solution while adjusting the temperature to 35 ° C. and stirring, and the former was added dropwise over 6 hours, and the latter over 4 hours.
After the dropping of tetramethoxysilane, stirring was continued for 0.5 hour to carry out hydrolysis to obtain a suspension of silica fine particles.

To the obtained suspension was added 547.4 g (3.39 mol) of hexamethyldisilazane at room temperature, and the mixture was heated to 55 ° C. and reacted for 3 hours to trimethylsilyl fine particles. Thereby, 3076 g of hydrophobic silica fine particle dispersion (solid content 17.7%)
was gotten.

In order to know the characteristics of the hydrophobic silica fine particles, the hydrophobic silica fine particles were taken out as follows. The solvent was distilled off from 100 g of the hydrophobic silica fine particle dispersion under reduced pressure to obtain 17.7 g of spherical hydrophobic silica fine particles having an average particle diameter of 0.12 μm. The following tests were performed on the obtained hydrophobic silica fine particles.

[Dispersibility test] Hydrophobic silica fine particles were added to an organic compound liquid at room temperature so that the weight ratio of organic compound: silica fine particles was 5: 1, and the mixture was shaken for 30 minutes using a shaker. After crushing, the dispersion state of the fine particles is visually observed and evaluated according to the following criteria. -A case where the whole amount of the fine particles was dispersed to form a uniform slurry was evaluated as ○;-A case where the whole amount of the fine particles was wet with the organic compound but was not partially dispersed in the organic compound and was uneven; A sample which was not wetted with the compound and did not mix with both was designated as x; The results are shown in Table 1.

[Aggregation Acceleration Test] (1) Fine particles are added to methanol at a weight ratio of 5: 1, and shaken for 30 minutes using a shaker. The particle size distribution of the fine particles treated as described above is measured by a laser diffraction scattering type particle size distribution analyzer (LA910, Horiba, Ltd.). (2) Next, methanol is distilled off from the fine particle dispersion obtained in (1) by heating using an evaporator, and then the mixture is kept at 100 ° C. for 2 hours. After adding the fine particles thus treated to methanol and shaking for 30 minutes using a shaker, the particle size distribution is measured in the same manner as described above. The ratio of the residual amount of the primary particles is determined based on the particle size distribution obtained in (1). The primary particle diameter is confirmed in advance by observation with an electron microscope. The results are shown in Table 1.

II. [Synthesis of Polymerization Method Toner] (1) 450 g of a 0.1 M Na ₃ PO ₄ aqueous solution was added to 710 g of ion-exchanged water, heated to 60 ° C., and then subjected to a TK homomixer (specialized (Industrial product) at 12,000 rpm. To this 1.
68 g of a 0 M CaCl ₂ aqueous solution was gradually added to obtain an aqueous dispersion containing Ca ₃ (PO ₄ ) ₂ . (2) Styrene 180 g, 2-ethylhexyl acrylate 20
g, CI Pigment Yellow 17 10 g, paraffin wax (mp 80 ° C) 30 g, heated to 60 ° C, TK homomixer
Dissolve uniformly at 12,000 rpm using
Dispersed. To this, a polymerization initiator, 2,2′-azobis (2,4-
10 g of dimethylvaleronitrile) and dimethyl-2,2'-
1 g of azobisisobutyrate was dissolved to prepare a polymerizable monomer system. The polymerizable monomer system was charged into the above aqueous dispersion, and the mixture was stirred at 9,000 rpm for 20 minutes with a TK homomixer at 60 ° C. in an N ₂ atmosphere to granulate the polymerizable monomer system. Thereafter, the reaction was carried out at 60 ° C. for 5 hours while stirring with a paddle stirring blade, and then the reaction was carried out at a liquid temperature of 80 ° C. for 10 hours.
Thereafter, the mixture was cooled, hydrochloric acid was added to dissolve Ca ₃ (PO ₄ ) _2, and 2085 g (solid content: 11.5%) of a polymerized toner aqueous dispersion was obtained. (3) In order to know the characteristics of the polymerization method toner, the polymerization method toner was taken out as follows. 100 g of the polymerized toner aqueous dispersion was filtered, washed with water and dried to obtain 11.5 g of the polymerized toner. The average particle size of the obtained polymerization toner is
8.0 μm.

III. [Production of Toner with Externally Added Hydrophobic Silica Fine Particles] The aqueous dispersion of the polymerized toner obtained in the above II. Was adjusted such that the hydrophobic silica fine particles accounted for 5% by weight of the polymerized toner. The above I.I. 32.5 g of the aqueous silica fine particle dispersion obtained in the above was added, and the mixture was stirred and mixed for 1 hour. The obtained mixture was filtered, washed with water, and dried to obtain 120 g of a toner to which hydrophobic silica fine particles were externally added. Using this, the degree of aggregation was evaluated by the following method.

[Agglomeration degree] The agglomeration degree is a value indicating the fluidity of the powder, and is measured with a powder tester manufactured by Hosokawa Micron Corporation.
The measurement was performed using a three-stage sieve in which sieves of 0, 100, and 60 mesh were sequentially stacked. As a measuring means, a powder consisting of 5 g of toner is placed on the upper 60-mesh sieve of the three-stage sieve, and a voltage of 2.5 V is applied to the powder tester, and the three-stage sieve is vibrated for 15 seconds. A (g) of the powder remaining on the sieve, b (g) of the powder remaining on the 100 mesh sieve, and c (g) of the powder remaining on the 200 mesh sieve according to the following formula Calculate the degree. Cohesion (%) = (a + b × 0.6 + c × 0.2) × 100/5 The smaller the cohesion, the better the fluidity, and the larger the cohesion, the poorer the fluidity. The results are shown in Table 1.

IV. [Preparation of Developer] 5 parts of the toner externally added with hydrophobic silica fine particles prepared in the above III, and ferrite core fine particles having an average particle diameter of 85 μm were mixed with a perfluoroalkyl acrylate resin and an acrylic resin. Carrier coated with polyblend polymer
95 parts were mixed to prepare a developer. Using this, toner adhesion to the photoreceptor was evaluated by the following method.

[Evaluation of Toner Adhesion to Photoconductor] The above-mentioned developer was put into a two-component modified developing machine equipped with an organic photoconductor,
A print test of 0 sheets was performed. At this time, the adhesion of the toner to the photoreceptor can be sensed as white spots in all solid images. The degree of white spots is evaluated according to the following criteria. Table 1 shows the results of “more” 10 or more / cm ² , “less” 1 to 9 / cm ² , and “none” 0 / cm ² .

Example 2 3021 g of hydrophobic silica fine particle dispersion liquid was prepared in the same manner as in Example 1 except that the hydrolysis temperature of tetramethoxysilane was changed to 20 ° C. instead of 35 ° C. in the synthesis of spherical hydrophobic silica fine particles.
(Solid content 17.9%) was obtained. In order to know the characteristics of the hydrophobic silica fine particles, the hydrophobic silica fine particles were taken out. The solvent was distilled off from 100 g of the hydrophobic silica fine particle dispersion under reduced pressure to obtain 17.9 g of spherical hydrophobic silica fine particles having an average particle diameter of 0.30 μm. The same test as in Example 1 was performed on the obtained hydrophobic silica fine particles. Further, in the same manner as in Example 1, a polymerization toner and a developer to which hydrophobic silica fine particles were externally added were prepared and evaluated. The results are shown in Table 1.

Example 3 Hydrophobic silica fine particles were dispersed in the same manner as in Example 1 except that the hydrolysis temperature of tetramethoxysilane was changed to 40 ° C. instead of 35 ° C. in the synthesis of spherical hydrophobic silica fine particles. 3033 g of a medium (solid content: 17.8%) was obtained. In order to know the characteristics of the hydrophobic silica fine particles, the hydrophobic silica fine particles were taken out. Medium in which hydrophobic silica fine particles are dispersed
The solvent was distilled off from 100 g under reduced pressure to obtain 17.8 g of spherical hydrophobic silica fine particles having an average particle size of 0.09 μm. The same test as in Example 1 was performed on the obtained hydrophobic silica fine particles.
Further, in the same manner as in Example 1, a polymerization toner and a developer to which hydrophobic silica fine particles were externally added were prepared and evaluated.
The results are shown in Table 1.

Example 4 [Synthesis of Spherical Hydrophobic Silica Fine Particle Dispersion Medium] 623.7 g of methanol, 41.4 g of water, and 49.8 g of 28% aqueous ammonia were added to a 3-liter glass reaction complex equipped with a stirrer, a dropping funnel and a thermometer. Added and mixed. The solution was adjusted to 35 ° C., and while stirring, 1163.7 g of tetramethoxysilane and 418.1 g of 5.4% aqueous ammonia were simultaneously added, and the former was added dropwise over 6 hours, and the latter over 4 hours. After the dropping of tetramethoxysilane, stirring was continued for 0.5 hour to carry out hydrolysis to obtain a suspension of silica fine particles. Attach the ester adapter and cooling tube to the glass reactor, heat to 60-70 ° C, and add 1132 g of methanol
Was distilled off, 1200 g of water was added, and then another 7 g
The mixture was heated to 0 to 90 ° C., and 273 g of methanol was distilled off to obtain an aqueous suspension of silica fine particles. To this aqueous suspension, 11.6 g of methyltrimethoxysilane (0.01 mol per 1 mol of tetramethoxysilane) was added dropwise over 0.5 hours at room temperature, and after the addition, the mixture was stirred for 12 hours to treat the surface of the silica fine particles.

After 1440 g of methyl isobutyl ketone was added to the dispersion thus obtained, the mixture was heated to 80 to 110 ° C., and 1163 g of methanol water was distilled off over 7 hours to obtain a dispersion using the ketone as a dispersion medium. Hexamethyldisilazane 35 at room temperature
7.6 g was added, the mixture was heated to 120 ° C., and reacted for 3 hours to trimethylsilyl fine particles. As a result, 2409 g (solid content: 19.8%) of a hydrophobic silica fine particle dispersion was obtained. In addition,
In order to know the characteristics of the hydrophobic silica fine particles, the hydrophobic silica fine particles were taken out. The solvent is distilled off from the hydrophobic silica fine particle dispersion liquid 100 g under reduced pressure, and the average particle diameter is 0.12 μm.
17.7 g of spherical hydrophobic silica fine particles were obtained. The same test as in Example 1 was performed on the obtained hydrophobic silica fine particles. Further, in the same manner as in Example 1, a polymerization toner and a developer to which hydrophobic silica fine particles were externally added were prepared and evaluated. The results are shown in Table 1.

Example 5 170 g of styrene was used as a monomer when synthesizing a polymerization toner.
30 g of n-butyl acrylate, CI Pigment Blue 15
In the same manner as in Example 1 except that the amount was changed to −10 g and paraffin wax (mp 70 ° C.) 60 g, 2120 g (solid content: 12.7%) of a polymerized toner aqueous dispersion was obtained. In order to know the characteristics of the obtained polymerization toner, the polymerization toner was taken out.
100 g of the polymerized toner aqueous dispersion was filtered, washed with water, and dried to obtain 12.7 g of a polymerized toner. The average particle diameter of the obtained polymerization toner was 8.0 μm. Further, in the same manner as in Example 1, a toner and a developer to which hydrophobic silica fine particles were externally added were prepared and evaluated. The results are shown in Table 1.

Comparative Example 1 Hydrophobic silica fine particles taken out in Example 1
5 g and 95 g of the polymerized toner removed were mixed in a dry state in a sample mill to obtain a toner to which hydrophobic silica fine particles were externally added. A developer was prepared and evaluated in the same manner as in Example 1 except that this toner was used. The results are shown in Table 1.

Comparative Example 2 95 g of the polymerized toner removed in Example 1 and commercially available hydrophobic wet silica fine particles (trade name: Nipsil SS50)
F, 5 g of Nippon Silica Co., Ltd.) was mixed in a dry state with a sample mill to obtain a toner to which hydrophobic silica fine particles were externally added. A developer was prepared and evaluated in the same manner as in Example 1 except that this toner was used. The results are shown in Table 1.

Comparative Example 3 A sample mill was prepared by drying 95 g of the polymerized toner obtained in Example 1 and 5 g of silica fine particles (trade name: Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) obtained by hydrophobizing fumed silica. And a toner to which hydrophobic silica fine particles were externally added was obtained. A developer was prepared and evaluated in the same manner as in Example 1 except that this toner was used.
The results are shown in Table 1.

[0073]

[Table 1] Note: MIBK: methyl isobutyl ketone, THF: tetrahydrofuran, D _5: decamethylcyclopentasiloxane

[0074]

According to the present invention, a toner in which a fluidity-imparting agent as an external additive is uniformly adhered to polymerized toner particles by a simple method can be obtained. The use of this toner not only improves the fluidity, caking resistance, fixability, and cleaning properties of the developer, but also significantly suppresses the deterioration and abrasion of the photoconductor and the adhesion of the toner to the photoconductor.

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Claims (5)

[Claims] 1. A process comprising mixing a polymerized toner aqueous dispersion obtained by suspension-polymerizing a polymerizable monomer in an aqueous medium with a dispersion in which a fluidity-imparting agent is dispersed in a medium; Removing the aqueous medium used for the suspension polymerization and the medium used for dispersing the fluidity-imparting agent from the mixed solution to obtain a toner externally added with the fluidity-imparting agent. A method for producing a toner to which a fluidity-imparting agent is externally added. 2. The method of claim 1, wherein the fluidity-imparting agent comprises the following conditions (i) and (i):
The method for producing a polymerization toner according to claim 1, wherein the particles are spherical hydrophobic silica fine particles satisfying i) and having an average primary particle size of 0.01 to 5 µm. (i) When an organic compound which is liquid at room temperature and has a dielectric constant of 1 to 40 F / m and silica fine particles are mixed at a weight ratio of 5: 1 and shaken, the silica fine particles are contained in the organic compound. Disperse evenly. (ii) After evaporating methanol from a dispersion of the silica fine particles in methanol by heating with an evaporator, 100
When kept at a temperature of ° C for 2 hours, it remains as primary particles
The ratio of the primary particle amount to the initially existing primary particle amount is 20%
That is all. Wherein the spherical hydrophobic silica fine particles, Si0 R ¹ to hydrophilic silica fine particle surface consisting of ₂ units ₃ SiO _1/2 units (wherein, R ¹ is a substituted or unsubstituted carbon atoms of the same or different The method for producing a toner according to claim 2, wherein the toner is obtained by introducing a monovalent hydrocarbon group having the following formulas (1 to 6). Wherein said spherical hydrophobic silica fine particles, R ² SiO _3/2 units to hydrophilic silica fine particle surface made of SiO ₂ units (wherein, R ² is a substituted or unsubstituted 1 to 20 carbon atoms R ¹ a monovalent hydrocarbon group) are hydrophobic silica fine particles surface obtained by introducing a ₃ SiO _1/2 units (wherein, R ¹ is the same or different substituted or unsubstituted 1 to 6 carbon atoms (Monovalent hydrocarbon group)
Claim 2 obtained by introducing
3. The method for producing a toner according to item 1. 5. A polymerizable toner comprising a polymerized toner and a fluidity-imparting agent externally added to the polymerized toner, wherein the fluidity-imparting agent satisfies the following conditions (i) and (ii): A toner comprising spherical hydrophobic fine silica particles having an average particle size of secondary particles of 0.01 to 5 μm. (i) When an organic compound which is liquid at room temperature and has a dielectric constant of 1 to 40 F / m and silica fine particles are mixed at a weight ratio of 5: 1 and shaken, the silica fine particles are contained in the organic compound. Disperse evenly. (ii) After heating and evaporating methanol with a evaporator from a dispersion in which the silica fine particles are dispersed in methanol, 100 ° C.
At the same temperature for 2 hours, remain as primary particles 1
20% ratio of primary particles to primary particles
That is all.