JP2001255698A - Electrostatic latent image developing toner and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic latent image developing toner having a small particle size and having excellent electrification rising property and electrification stability and good image characteristics for a long time, and to provide a method of manufacturing the toner. SOLUTION: The method of manufacturing the electrostatic latent image developing toner consists of a process of preparing a color resin solution by dissolving and/or dispersing at least a binder resin and a coloring agent in a water-insoluble organic solvent; a process of preparing an emulsion by emulsifying and dispersing the color resin solution in a water-based dispersion liquid in which an antistatic agent is dissolved and/or dispersed or a process of forming an emulsion by adding a water-based dispersion liquid in which an antistatic agent is dissolved and/or dispersed to the color resin solution to convert the phase and to emulsify; and a process of removing the water-insoluble organic solvent from the emulsion. The electrostatic latent image developing toner is manufactured by this method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a toner for developing an electrostatic latent image and a method for producing the same. More specifically, the present invention relates to a toner for developing an electrostatic latent image used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art An emulsification dispersion method is known as one of the methods for producing resin fine particles. In this method, a resin solution obtained by dissolving a resin in a water-insoluble organic solvent is emulsified and dispersed in an aqueous dispersion to form an emulsion, and heat is added to the emulsion while stirring to remove the organic solvent. The resin fine particles are obtained by removing by evaporation. According to this emulsification dispersion method, it is possible to obtain polymer fine particles having an average particle size of about 1 to 10 μm with a relatively simple operation and a relatively simple operation, and the production efficiency is improved as compared with a pulverization method or a suspension polymerization method. At the same time, costs can be reduced. Also, there are many types of resins that can be used as compared with the suspension polymerization method and the like.

Therefore, by applying such an emulsification dispersion method,
By blending toner components such as colorants, charge control agents, and magnetic powder in the resin solution, electrostatic latent images that meet the needs of electrophotographic copiers and printers, such as high speed, high image quality, and colorization It is expected that the developing toner can be obtained relatively easily and at low cost. For example, JP-A-61-91666 and JP-A-63-25664 disclose a method for producing a toner for developing an electrostatic latent image using such an emulsion dispersion method.

[0004] However, the method of producing a toner by the emulsification dispersion method is intended to satisfy the recent demand for higher image quality.
This is a convenient method for obtaining a toner having a small particle size, but there is a problem that the smaller the toner particle size, the higher the charge amount and the lower the density of the obtained image quality.

Further, the toner finally obtained by the conventional emulsification dispersion method has a problem that water is easily taken into oil droplets of the O / W emulsion, or that there are many internal cavities. If there are many internal cavities like this, the toner is easily broken,
At the time of durability, the chargeability was remarkably reduced, and the occurrence of fog was a problem (charge stability).

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is a toner for developing an electrostatic latent image having a small particle diameter, which is excellent in charge rising property and charge stability and has good image characteristics over a long period of time. And a method for producing the same.

[0007]

According to the present invention, there is provided a process for dissolving and / or dispersing at least a binder resin and a colorant in a water-insoluble organic solvent to obtain a color resin solution, and dissolving the antistatic agent in the color resin solution. And / or emulsifying and dispersing in a dispersed aqueous dispersion to form an emulsion, or adding an aqueous dispersion in which an antistatic agent is dissolved and / or dispersed to a colored resin solution and phase inverting to form an emulsion. And a process for removing a water-insoluble organic solvent from an emulsion, and a method for developing an electrostatic latent image developing toner and an electrostatic latent image developing toner produced by the method.

In the present invention, by producing a toner according to the present invention, a toner having reduced particle cavities and a sharp particle size distribution can be obtained.
The toner does not disintegrate even during running, and good chargeability stability is obtained, and good charge rising property is obtained by achieving a sharp particle size distribution.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the method of the present invention, first, at least a binder resin and a colorant are dissolved and / or dispersed in a water-insoluble organic solvent to obtain a colored resin solution.

The binder resin is not particularly limited as long as it is soluble in the water-insoluble organic solvent used and is insoluble or hardly soluble in water. Styrenic resin,
(Meth) acrylic resin, styrene- (meth) acrylic copolymer resin, olefin resin, polyester resin, polyamide resin, carbonate resin, polyether, polyvinyl acetate resin, polysulfone, epoxy resin, polyurethane It is possible to use one kind or two or more kinds of known various resins such as resin and urea resin.

Further, such a binder resin is made of glass from the viewpoints of heat resistance, fixability, offset resistance (for high-temperature offset and low-temperature offset) of the toner, and expansion of the temperature range (non-offset region) where no offset occurs. The transition point (Tg) is 50-70 ° C., and the number average molecular weight (Mn) is 1000-50,000, preferably 3,000-20,000, Mn.
It is desirable that the molecular weight distribution (Mw / Mn) expressed by the ratio of the weight average molecular weight (Mw) to 2-60. Further, in the case of using an oil-fixing toner, Mw / Mn is more preferably 2 to 5, and in the case of using an oilless fixing toner, Mw / Mn is more preferably 20 to 50. desirable.

The water-insoluble organic solvent may be any one which is insoluble or hardly soluble in water and which dissolves the binder resin as described above. Examples thereof include toluene, xylene, benzene, carbon tetrachloride, and methylene chloride. , 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone and the like can be used alone or in combination of two or more. , Of which toluene,
Aromatic solvents such as xylene and methylene chloride;
-Halogenated hydrocarbons such as dichloroethane, chloroform, carbon tetrachloride and the like are usually preferably used.

As the coloring agent, various organic or inorganic pigments of various colors as shown below can be used.
That is, examples of black pigments include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, non-magnetic ferrite, magnetic ferrite, and magnetite. Examples of yellow pigments include: lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hanza yellow G, Hanza yellow 10G, benzidine yellow G, benzidine yellow GR, quinoline There are yellow lake, permanent yellow NCG, tartrazine lake and the like.

Examples of the orange pigment include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indaslen brilliant orange RK, benzidine orange G, and indaslen brilliant orange GK. Red pigments include Bengala, Cadmium Red, Lead Tan, Mercury Sulfide, Cadmium, Permanent Red 4R, Lisor Red,
Pyrazolone red, watching red, calcium salt, lake red C, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake, brilliant carmine 3B, quinacridone and the like. Examples of purple pigments include manganese purple, fast violet B, and methyl violet lake.

Blue pigments include navy blue, cobalt blue, alkaline blue lake, Victoria blue lake,
Phthalocyanine blue, metal-free phthalocyanine blue,
Copper phthalocyanine blue, partially chlorinated phthalocyanine blue, Fast Sky Blue, Indaslen Blue BC and the like. As green pigments, chrome green,
Chromium oxide, Pigment Green B, Mica Light Green Lake, Final Yellow Green G, and the like. Examples of white pigments include zinc white, titanium oxide, antimony white, and zinc sulfide. The extender includes baryte powder, barium carbonate, clay, silica, white carbon, talc, alumina white and the like.

The above colorant may be used in the form of a master batch. That is, the dispersibility of the coloring agent in the coloring resin solution is improved by using the coloring agent as a masterbatch previously dispersed in a resin compatible with the binder resin. The masterbatch melts and kneads a resin compatible with the colorant and the binder resin, and has a particle size of 0.1-2.
It can be obtained by crushing to about 0 mm, preferably 1 to 5 mm. The resin compatible with the binder resin is a resin that is compatible with the binder resin used, is soluble in the water-insoluble organic solvent, and is insoluble or hardly soluble in water. It is not particularly limited.

The amount of the coloring agent is not particularly limited, but is preferably 1 to 15 parts by weight based on 100 parts by weight of the binder resin. When the coloring agent is used in the form of a master batch, the amount of the coloring agent contained in the used master batch may be within the above range.

In the colored resin solution, for example, a toner component such as a charge controlling agent, an anti-offset agent, and a magnetic powder can be added as required in addition to the binder resin and the coloring agent as described above. .

The charge control agent is used when the charge characteristics of the toner cannot be satisfied with only the binder resin and the colorant. The charge control agent imparts positive or negative chargeability to the toner particles by frictional charge. Has the effect of promptly increasing to a predetermined charge amount. As such a charge control agent, a positive charge control agent or a negative charge control agent known in the field of toner for developing an electrostatic latent image can be used. Specific examples of the positive charge control agent include, for example, Nigrosine Base EX
Nigrosine dyes such as (manufactured by Orient Chemical Industries),
The fourth such as Bontron P-51 (manufactured by Orient Chemical Industries) and Copy Charge PX VP435 (manufactured by Hoechst Japan)
Examples include, but are not limited to, quaternary ammonium salts, alkoxylated amines, alkylamides, molybdic acid chelate pigments, and imidazole compounds such as PLZ1001 (manufactured by Shikoku Chemicals).

Specific examples of the negative charge control agent include Bontron S-22 (manufactured by Orient Chemical Industries), Bontron S-34 (manufactured by Orient Chemical Industries), Bontron E-
Metal complexes such as 81 (manufactured by Orient Chemical Co., Ltd.), Bontron E-84 (manufactured by Orient Chemical Co., Ltd.), Spiron Black TRH (manufactured by Hodogaya Chemical Co., Ltd.), thioindigo pigments,
Quaternary ammonium salts such as Copy Charge NX VP434 (manufactured by Hoechst Japan), calixarene compounds such as Bontron E-89 (manufactured by Orient Chemical Industries), LR14
Boron compounds such as 7 (manufactured by Nippon Carlit Co., Ltd.), and fluorine compounds such as magnesium fluoride and carbon fluoride, but of course, are not limited thereto. In addition, as a metal complex which becomes a negative charge control agent,
Metal oxycarboxylate complexes other than those shown above,
Includes those having various structures such as dicarboxylic acid metal complex, amino acid metal complex, diketone metal complex, diamine metal complex, azo group-containing benzene-benzene derivative skeleton metal body, and azo group-containing benzene-naphthalene derivative skeleton metal complex. .

The charge controlling agent is dissolved in the colored resin solution and / or
Or when dispersed, the addition amount of the charge control agent is 0.1 to 5 parts by weight, preferably 0.5 to 2 parts by weight per 100 parts by weight of the binder resin.
Parts by weight are preferred.

The anti-offset agent is used to improve the fixability of the toner, and specific examples thereof include various waxes, particularly low-molecular-weight polypropylene and polyethylene, or polyolefin-based wax such as oxidized polypropylene and polyethylene. Can be

Examples of the magnetic powder include magnetite, γ-hematite, and various ferrites.

For dissolving and / or dispersing the above-mentioned materials in the water-insoluble organic solvent, a known mixing device or stirring device is used, and examples thereof include a ball mill, a sand grinder, and an ultrasonic homogenizer.
In the present invention, from the viewpoint of efficiently dissolving and / or dispersing the above-mentioned materials, it is preferable to use a mixing device using ultrasonic waves, for example, an ultrasonic homogenizer.

When the O / W emulsion obtained in the subsequent step is heated to remove the water-insoluble organic solvent from the droplets, the solids concentration in the colored resin solution can be easily changed into fine particles. It is necessary to set such that solidification is possible. In particular, the concentration of the polymer component in the polymer solution is set to 5 to 50% by weight, more preferably about 10 to 40% by weight.

Next, the obtained colored resin solution is emulsified and dispersed in an aqueous dispersion to form an O / W emulsion, or the aqueous dispersion is added to the colored resin solution to carry out phase inversion emulsification to form an O / W emulsion. Form an emulsion.

The aqueous dispersion used in the present invention comprises an antistatic agent dissolved and / or dispersed in an aqueous medium. As the aqueous medium, water can be basically used, but a water-soluble organic solvent may be contained to such an extent that the emulsion is not destroyed. For example, water, a water / methanol mixture (weight ratio 50/50 to 100/0), a water / ethanol mixture (weight ratio 50/50 to 100/0), and a water / acetone mixture (50/50 to 100/0)
0), water / methyl ethyl ketone mixed solution (weight ratio 70 / 30-100 /
0) can be used.

As the antistatic agent, a permanent antistatic agent is generally used in the field of plastics, in which the plastic is kneaded or applied to the surface of the plastic to impart water absorbability to the plastic to prevent electrification. Various substances can be used as long as they can be uniformly dissolved or dispersed in the aqueous dispersion. In particular, the toner tends to be excessively charged as the particle size of the toner decreases, but in the present invention, the antistatic agent acts to reduce the charge amount of the toner and suppresses the excessive charging of the small particle size toner. It works to charge properly. In the production of a toner by the conventional emulsification dispersion method, cavities are easily formed inside the toner particles, and the adverse effects (toner collapse and associated charging instability) are large. Such cavities inside the particles are considered to be caused by water being taken into oil droplets of the emulsion at the time of emulsification and dispersion, and particularly when a toner is manufactured by adding an aqueous charge control agent to a colored resin solution, The occurrence of cavities inside the obtained toner becomes remarkable. In the method of the present invention, by adding the antistatic agent to the aqueous dispersion, particularly when the aqueous charge control agent is added to the colored resin solution, the cavities inside the particles are reduced. And a toner having a sharp particle size distribution can be obtained. Since the cavities inside the toner particles can be reduced, the toner is prevented from collapsing at the time of durability, and good chargeability stability is secured. Therefore, the toner obtained by the method of the present invention has a sharp particle size distribution, ensures uniform triboelectric charging, and has a good charge rising property.

Examples of the antistatic agent include quaternary ammonium salt-based copolymers, alkane sulfonate-based compounds, diethanolamine-based compounds, phosphonium salt-based compounds, polyetherester-based compounds, and polyalkylene glycol copolymers. Can be used, and as specific examples of the antistatic agent as described above, for example, Leorex AS
-170 (manufactured by Daiichi Kogyo Seiyaku), Atrai AS-1030 (manufactured by Nikko Petrochemical), Hostat HS-1 (manufactured by Hoechst Japan), AS-1000, AS-4000, Cactus SAS-195, SAS-495
(Manufactured by Nippon Petrochemical Co., Ltd.), Hostafar SAS-93, SAS-60
(Manufactured by Hoechst Japan Co., Ltd.) and the like, but are of course not limited thereto.

The amount of the antistatic agent to be added depends on whether the content of the antistatic agent in the obtained O / W emulsion is water-soluble, from the viewpoint of a decrease in the toner charge amount due to the water absorption of the antistatic agent and a change in the charge amount due to environmental fluctuation. 0.0 for 100 parts by weight of medium
The amount is desirably 5 to 5 parts by weight, preferably 0.1 to 3 parts by weight.

It is preferable that a dispersion stabilizer is added to the aqueous dispersion from the viewpoint of the stability of the obtained O / W emulsion. The dispersion stabilizer has a hydrophilic colloid in an aqueous dispersion, and is particularly gelatin, gum arabic, agar, cellulose derivatives (for example, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, etc.), synthetic polymers (polyvinyl alcohol, Polyvinylpyrrolidone, polyacrylamide,
Polyacrylate, polymethacrylate, etc.). Also, solid fine powder can be used. Examples include tricalcium phosphate, calcium carbonate, calcium sulfate, barium carbonate, silica, titanium oxide, and alumina. It is also possible to add a dispersion stabilizing aid as needed. Surfactants are usually used as a dispersion stabilizing aid, and natural surfactants such as saponin, nonionic surfactants such as alkylene oxides, glycerins, and glycidols, carboxylic acids, sulfonic acids, phosphoric acids, and sulfate groups are used. And an anionic surfactant containing an acidic group such as a phosphate group (eg, sodium lauryl sulfate). Particularly preferred in combination with the dispersion stabilizer and the dispersion stabilizing aid are polyvinyl alcohol or tricalcium phosphate and an anionic surfactant.

In the aqueous dispersion, a positive or negative charge control agent exemplified as a toner component which may be blended in the colored resin solution may be dissolved and / or dispersed. By adding a charge control agent to the aqueous dispersion, the presence of fine particles or coat layer of the charge control agent on the surface of the toner particles,
This is because positive or negative chargeability can be effectively imparted to the toner particles, and the toner charge amount (the absolute value of the charge amount held by the toner) can be efficiently increased. When the charge control agent is dissolved and / or dispersed in the aqueous dispersion, the amount of the charge control agent is preferably 0.05 to 5 parts by weight, and more preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the aqueous medium.

In forming an O / W emulsion,
Specifically, while stirring the aqueous dispersion using a known stirring device such as a homomixer, the colored resin solution is added to the aqueous dispersion, and the mixed system may be sufficiently stirred, or While stirring the colored resin solution using a stirrer, the aqueous dispersion may be added to the colored resin solution, and when the phase inversion occurs, the addition may be stopped and the mixed system may be sufficiently stirred.
The stirring time is preferably 10 minutes or more. If the stirring time is too short, a sharp particle size distribution cannot be obtained.

In the case where an O / W emulsion is formed by causing phase inversion, while the colored resin solution is stirred using the above-mentioned stirring device, the aqueous solution containing no antistatic agent is added to the colored resin solution. Add the dispersion, stop adding the dispersion before phase inversion occurs, and then further add an aqueous dispersion containing an antistatic agent, stop the addition when phase inversion occurs, and stir the mixed system sufficiently. May be. The concentration of the antistatic agent in the aqueous dispersion containing the antistatic agent is set such that the content of the antistatic agent in the obtained O / W emulsion with respect to 100 parts by weight of the aqueous medium is within the above range.

The particle size of each droplet of the colored resin solution in the emulsion directly affects the size of the finally obtained toner fine particles. And its particle size distribution must be well controlled.

When preparing an O / W emulsion by emulsification and dispersion, the ratio of the volume (Vp) of the colored resin solution to the volume (Vw) of the aqueous dispersion is Vp / Vw ≦ 1, more preferably 0.1.
It is desirable to be in the range of 3 ≦ Vp / Vw ≦ 0.7. That is, when Vp / Vw> 1, a stable O / W emulsion is difficult to be formed, and there is a high possibility that a phase transition occurs or a W / O emulsion is formed on the way.

After forming the O / W emulsion as described above, the water-insoluble organic solvent is removed from the emulsion. That is, the water-insoluble organic solvent is completely removed from the droplet particles in the emulsion to form toner fine particles.

As the removal method, a conventional method, for example, a method of removing the water-insoluble organic solvent by gradually raising the temperature of the whole system (may be under reduced pressure), or a method of drying the O / W emulsion in a dry atmosphere It is also possible to employ a method in which the water-insoluble organic solvent in the droplets is completely removed to form toner fine particles by completely removing the water-insoluble organic solvent, and the aqueous medium is removed by evaporation. At this time, the drying atmosphere is air, nitrogen, carbon dioxide,
A gas obtained by heating a combustion gas or the like from 20 ° C. to 250 ° C., in particular, various gas streams heated to a temperature equal to or higher than the boiling point of the highest boiling solvent used is generally used.

In the method for producing a toner according to the present invention, when removing the water-insoluble organic solvent from the emulsion while reducing the pressure, it is preferable to desolve the emulsion while supplying water to the emulsion. By doing so, foaming of the emulsion due to reduced pressure can be prevented, the solid-liquid concentration in the emulsion can be kept constant, the generation of cavities in the toner particles can be more effectively suppressed, and furthermore, irregularly shaped particles and aggregated particles can be prevented. Is also suppressed.

FIG. 1 is a schematic structural view showing an example of a desolving apparatus for performing the above method. In detail, the desolving apparatus is connected to at least a storage tank 2 for storing the emulsion 1, a storage tank, a water supply unit 4 for supplying water 3, and a storage tank, and Cooling tower 5 for liquefaction, collection unit 6 for once collecting liquefied liquid, collection unit 7 for collecting collected liquid
And a pump 8 for reducing the pressure inside the system.

The water supply section 4 is provided with a ventilation pipe 11 for keeping the pressure of the water surface of the water 3 and the pressure of the liquid surface of the emulsion 1 equal. For this reason, water can be supplied into the system under reduced pressure, foaming of the emulsion due to reduced pressure is prevented, and generation of cavities in toner particles can be more effectively suppressed. Further, a valve 10 for shutting off the inside of the system from outside air is provided above the water supply unit 4, and is closed during the removal of the water-insoluble organic solvent. On the other hand, a valve 12 for appropriately supplying the water 3 to the emulsion is provided below the water supply unit 4.

In the storage tank 2, the water-insoluble organic solvent is vaporized (evaporated). A heater (not shown) for heating the emulsion may be provided inside or outside the storage tank to efficiently remove the water-insoluble organic solvent. Further, a stirring device 13 is provided so that the droplets in the emulsion 1 are not unevenly distributed.

When the water-insoluble organic solvent is removed from the emulsion 1, not only the water-insoluble organic solvent but also the water in the emulsion evaporates by azeotropy. In the apparatus, the concentration of the droplet particles in the emulsion increased, and the droplet particles aggregated to form irregular toner particles or aggregated toner particles. In the apparatus, water was supplied from the water supply unit 4. However, since the solvent is removed under reduced pressure, the droplet particle concentration in the emulsion can be kept constant,
The generation of irregularly shaped particles and aggregated particles can be effectively prevented while efficiently removing the water-insoluble organic solvent.

The mixed gas of the water-insoluble organic solvent and water vaporized in the storage tank 2 is liquefied by the cooling tower 5, and the liquefied mixed liquid is once collected in the collecting part 6 connected below. .

The collecting section 6 is provided with a vent pipe 14 for keeping the internal pressure of the collecting section equal to the internal pressure of the collecting section connected therebelow. For this reason, it is possible to recover the mixed liquid under reduced pressure. A valve 15 for appropriately dropping the collected liquid mixture to the collection section 7 is provided below the collection section 6, and the mixed liquid is collected in the collection section 7 by opening the valve 15. ing.

After removing the water-insoluble organic solvent, the obtained toner fine particles can be washed, dried and classified as necessary to obtain the toner for developing an electrostatic latent image of the present invention.
The weight average particle diameter (d50) of the toner is preferably about 1 to 13 μm, and more preferably about 3 to 9 μm.

The toner obtained by the above method comprises at least a binder resin and a colorant, and has at least an antistatic agent on its surface in the form of fine particles or a coat layer. It has a configuration in which the inhibitor and the charge control agent are present in the form of fine particles or coat layer, respectively. The surface existing form of the antistatic agent and the charge control agent depends on the solubility in each aqueous medium.

A fluidizing agent and a cleaning aid may be further added to the toner of the present invention. Examples of the fluidizing agent include silica, alumina, titanium oxide, zinc oxide, iron oxide, copper oxide, lead oxide, antimony oxide, yttrium oxide, magnesium oxide, barium titanate, ferrite, red iron oxide, magnesium fluoride, and silicon carbide. And inorganic fine particles such as boron carbide, silicon nitride, zirconium nitride, magnetite, and magnesium stearate. The inorganic fine particles may be subjected to a surface treatment for improving dispersibility on the surface of the toner particles and improving environmental stability. Examples of the surface treatment agent include a silane coupling agent, a titanium coupling agent, a higher fatty acid, and a silicone oil. As cleaning aids,
Polystyrene fine particles, polymethyl methacrylate fine particles and the like are used. The amount of each of these fluidizing agents and cleaning aids is preferably 0.1 to 20% by weight based on the toner particles. The fluidizing agent and the cleaning aid may each be used in combination of two or more materials. In this case, the total amount of each of the fluidizing agent and the cleaning aid may be within the above range.

The toner of the present invention is a two-component developer using a carrier, a one-component developer not using a carrier,
It can be used as any developer.

Further, the toner of the present invention is excellent in charge rising property and charge stability, and has good image characteristics over a long period of time. Further, the toner has a reduced particle size and a sharp particle size distribution.

In the method of the present invention, the above-mentioned antistatic agent is added to the aqueous dispersion to produce a toner.
The amount of the antistatic agent present on the surface of the toner particles is large. For this reason, it is possible to avoid the problem of a high charge amount caused by a reduction in the diameter of the toner. Hereinafter, the present invention will be described more specifically with reference to examples. Unless otherwise specified, “parts” means “parts by weight”.

[0052]

EXAMPLES Example 1 100 parts of polyester resin (softening point 95 ° C., Tg 65 ° C., Mn = 3500, Mw / Mn = 2.5) 4 parts of copper phthalocyanine blue pigment (manufactured by Toyo Ink Mfg.) Bontron E-84 (Orient Chemical) 2 copies

The above-mentioned material was added to 400 parts of toluene as a solvent and treated for 30 minutes using an ultrasonic homogenizer (output: 400 μA) to dissolve and disperse the above-mentioned material in the solvent to obtain a colored resin solution. Also,

-Dispersion stabilizer: polyvinyl alcohol PA18 (Shin-Etsu Chemical Co., Ltd.) 4 parts-Dispersion stabilization auxiliary agent: sodium lauryl sulfate (Wako Pure Chemical Industries) 0.1 part-Antistatic agent: Atrai AS-1030 (Nippon Mining Oil 0.25 parts

The above-mentioned material was added to 100 parts of water as a solvent, and the above-mentioned material was dissolved and dispersed in a solvent using a mixer to obtain an aqueous dispersion. While stirring 100 parts of the aqueous dispersion using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at 4,000 revolutions per minute, 50 parts of the above colored resin solution is dropped, and the average particle diameter of the droplets becomes about 6 μm. The mixture was emulsified and dispersed in water so as to be as follows. Then, toluene was removed under the conditions of 60 ° C., 100 mmHg, and 5Hr using a desolving apparatus having the configuration shown in FIG.
Filtration / washing was repeated to obtain toner particles 1 having an average particle size of 5.9 μm.

Example 2 Using the colored resin solution and the aqueous dispersion of Example 1, 50 parts of the colored resin solution was stirred at 4,000 rpm using an TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). The dispersion was added dropwise, and when the phase inversion occurred, the addition was stopped and the mixture was further stirred for 10 minutes. Then, toluene was removed under the conditions of 60 ° C., 100 mmHg, and 5Hr using a desolving apparatus having the configuration shown in FIG.
The filtration / washing was repeated to obtain toner particles 2 having an average particle size of 5.7 μm.

Example 3 An aqueous solution prepared by dissolving 4 parts of polyvinyl alcohol PA18 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a dispersion stabilizer and 0.1 part of sodium lauryl sulfate (manufactured by Wako Pure Chemical Industries) as a dispersion stabilizing agent in 100 parts of water. Dispersion II was prepared. Colored resin solution 50 of Example 1
Every minute using TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.)
While stirring at 4,000 revolutions, the aqueous dispersion II was dropped, and the dropping was stopped before phase inversion occurred. Further, the aqueous dispersion of Example 1 was dropped, and the dropping was stopped when phase inversion occurred. Stirred for minutes. Thereafter, toluene was removed under the conditions of 60 ° C., 100 mmHg, and 5 hours using a desolving apparatus having the configuration shown in FIG. 1, and filtration / washing was repeated to obtain toner particles 3 having an average particle size of 5.7 μm. .

Example 4 100 parts of styrene / n-butyl methacrylate resin (softening point 98 ° C., Tg 65 ° C., Mn = 8300, Mw / Mn = 2.3) Carbon black: MA # 8 (manufactured by Mitsubishi Chemical Corporation) 6 parts・ Charge control agent: Bontron P-51 (Orient Chemical) 0.4 part

The above material was added to 400 parts of toluene as a solvent, and treated with an ultrasonic homogenizer (output: 400 μA) for 30 minutes to dissolve and disperse the material in the solvent to obtain a colored resin solution. Also,

Dispersion stabilizer: tricalcium phosphate (manufactured by Wako Pure Chemical Industries, Ltd.) 4 parts Dispersion stabilizer: sodium lauryl sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) 0.1 part Antistatic agent: Atrai AS-1030 (Nikko) 0.4 parts by Petrochemical Co.)

The above materials were added to 100 parts of water as a solvent, and the above materials were dissolved and dispersed in a solvent using a mixer to obtain an aqueous dispersion. While stirring 100 parts of the aqueous dispersion using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at 5,000 revolutions per minute, 50 parts of the above colored resin solution is dropped, and the average particle diameter of the droplets becomes about 6 μm. The mixture was emulsified and dispersed in water so as to be as follows. Then, toluene was removed under the conditions of 60 ° C., 100 mmHg, and 5Hr using a desolving apparatus having the configuration shown in FIG.
After dissolving tricalcium phosphate with concentrated hydrochloric acid, filtration /
Washing was repeated to obtain toner particles 4 having an average particle diameter of 6.0 μm.

Example 5 100 parts of polyester resin (softening point 103 ° C., Tg 68 ° C., Mn = 6900, Mw / Mn = 2.2) 4 parts of quinacridone pigment (manufactured by Dainichi Seika)

The above material was added to 400 parts of toluene as a solvent, and treated with an ultrasonic homogenizer (output: 400 μA) for 30 minutes to dissolve and disperse the material in the solvent to obtain a colored resin solution. Also,

• Dispersion stabilizer: polyvinyl alcohol PA18 (Shin-Etsu Chemical Co., Ltd.) 4 parts • Dispersion stabilization aid: sodium lauryl sulfate (Wako Pure Chemical Industries) 0.1 part • Antistatic agent: Hostat HS-1 (Hoechst Japan) 0.2 parts

The above-mentioned materials were added to 100 parts of water as a solvent, and the above-mentioned materials were dissolved and dispersed in a solvent using a mixer to obtain an aqueous dispersion. While stirring 100 parts of the aqueous dispersion using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at 4,000 revolutions per minute, 50 parts of the above colored resin solution is dropped, and the average particle diameter of the droplets becomes about 6 μm. The mixture was emulsified and dispersed in water so as to be as follows. Then, toluene was removed under the conditions of 60 ° C., 100 mmHg, and 5Hr using a desolving apparatus having the configuration shown in FIG.
Filtration / washing was repeated to obtain toner particles 5 having an average particle diameter of 6.0 μm.

Comparative Example 1 100 parts of polyester resin (softening point 95 ° C., Tg 65 ° C., Mn = 3500, Mw / Mn = 2.5) 4 parts of copper phthalocyanine blue pigment (manufactured by Toyo Ink Mfg. Co.) E-84 (Orient Chemical) 2 parts ・ Antistatic agent: Atrai AS-1030 (Nikko Petrochemical) 2 parts

The above material was added to 400 parts of toluene as a solvent, and treated with an ultrasonic homogenizer (output: 400 μA) for 30 minutes to dissolve and disperse the material in the solvent to obtain a colored resin solution.

On the other hand, an aqueous dispersion obtained by dissolving 4 parts of polyvinyl alcohol PA18 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a dispersion stabilizer and 0.1 part of sodium lauryl sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) as a dispersion stabilizer in 100 parts of water. The liquid was adjusted. Dispersion 1
While stirring 00 parts with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at 4,000 revolutions per minute, 50 parts of the above colored resin solution is added dropwise so that the average particle diameter of the droplets is about 6 μm. It was emulsified and dispersed in water. Thereafter, toluene was removed under the conditions of 60 ° C., 100 mmHg, and 5 hours using a desolving apparatus having the configuration shown in FIG.
0 μm toner particles 6 were obtained.

Comparative Example 2 Styrene / n-butyl methacrylate resin 100 parts (softening point 98 ° C., Tg 65 ° C., Mn = 8300, Mw / Mn = 2.3) Carbon black: MA # 8 (manufactured by Mitsubishi Kasei) 6 parts・ Antistatic agent: Atrai AS-1030 (manufactured by Nikko Petrochemical Co.) 2 parts

The above material was added to 400 parts of toluene as a solvent, and treated with an ultrasonic homogenizer (output: 400 μA) for 30 minutes to dissolve and disperse the material in the solvent to obtain a colored resin solution. Also

Dispersion stabilizer: tricalcium phosphate (manufactured by Wako Pure Chemical Industries, Ltd.) 4 parts Dispersion stabilizer: sodium lauryl sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) 0.1 part

The above-mentioned materials were added to 100 parts of water as a solvent, and the above-mentioned materials were dissolved and dispersed in a solvent using a mixer to obtain an aqueous dispersion. While stirring 100 parts of the aqueous dispersion using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at 5,000 revolutions per minute, 50 parts of the above colored resin solution is dropped, and the average particle diameter of the droplets becomes about 6 μm. The mixture was emulsified and dispersed in water so as to be as follows. Then, toluene was removed under the conditions of 60 ° C., 100 mmHg, and 5Hr using a desolving apparatus having the configuration shown in FIG.
After dissolving tricalcium phosphate with concentrated hydrochloric acid, filtration /
Washing was repeated to obtain toner particles 7 having an average particle diameter of 6.2 μm.

Comparative Example 3 100 parts of polyester resin (softening point 103 ° C., Tg 68 ° C., Mn = 6900, Mw / Mn = 2.2) 4 parts of quinacridone pigment (manufactured by Dainichi Seika Co., Ltd.) Antistatic agent: Hostat HS- 1 (made by Hoechst Japan) 2 copies

The above material was added to 400 parts of toluene as a solvent, and treated with an ultrasonic homogenizer (output: 400 μA) for 30 minutes to dissolve and disperse the material in the solvent to obtain a colored resin solution. Also,

Dispersion stabilizer: 4 parts of polyvinyl alcohol PA18 (manufactured by Shin-Etsu Chemical Co., Ltd.) Dispersion stabilizer: sodium lauryl sulfate (manufactured by Wako Pure Chemical Industries) 0.1 part

The above materials were added to 100 parts of water as a solvent, and the above materials were dissolved and dispersed in a solvent using a mixer to obtain an aqueous dispersion. While stirring 100 parts of the aqueous dispersion using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at 4,000 revolutions per minute, 50 parts of the above colored resin solution is dropped, and the average particle diameter of the droplets becomes about 6 μm. The mixture was emulsified and dispersed in water so as to be as follows. Then, toluene was removed under the conditions of 60 ° C., 100 mmHg, and 5Hr using a desolving apparatus having the configuration shown in FIG.
Filtration / washing was repeated to obtain toner particles 8 having an average particle diameter of 6.1 μm.

Comparative Example 4 Except that the antistatic agent was not contained in the aqueous dispersion,
In the same manner as in Example 1, toner particles 9 having an average particle size of 6.0 μm
I got

Example 6 Toner particles 10 having an average particle size of 5.8 μm were obtained in the same manner as in Example 1, except that the charge control agent was not contained in the colored resin solution but in the aqueous dispersion. .

0.5% by weight of silica particles (H-2000 (manufactured by Hoechst Japan)) and 1% by weight of titanium dioxide particles (T-805) based on toner particles 1 to 3, 6, 9 and 10
(Manufactured by Nippon Aerosil Co., Ltd.)) and mixed with a Henschel mixer for 3 minutes to obtain toners 1 to 3, 6, 9, and 10. Further, 0.3% by weight of silica fine particles (R-974 (manufactured by Nippon Aerosil Co., Ltd.)) was added to toner particles 4 and 7, and mixed with a Henschel mixer for 2 minutes to obtain toners 4 and 7. 0.9% by weight of silica fine particles (R
-976 (manufactured by Nippon Aerosil Co., Ltd.) and mixed with a Henschel mixer for 2 minutes to obtain toners 5 and 8.

Production of carrier ・ Polyester resin (softening point 123 ° C., Tg 65 ° C., AV = 230, HV = 40) 100 parts ・ Ferrite fine particles: MFP-2 (manufactured by TDK) 500 parts ・ Carbon black: MA # 8 ( (Mitsubishi Kasei Co., Ltd.) 2 parts The above materials were thoroughly mixed with a Henschel mixer, kneaded with a twin-screw extruder, and the cooled mixture was coarsely pulverized with a feather mill, and then average particle size using a jet pulverizer and an air classifier. 50 μm carrier particles were obtained.

Evaluation Method 1) Charge Amount First, 30 g of a developer was prepared by mixing the toners obtained in Examples 1-4 and 6 and Comparative Examples 1-2 and 4 at a ratio of 5% by weight to the carrier. And this is 50cc
Put in a polyethylene bottle at 120 rpm for 5 minutes and 900
After rotating for minutes, the charge amount was measured.

2) Image Characteristics The toners of Examples 1 to 3 and 6 and Comparative Examples 1 and 4 were mixed with a carrier to prepare a developer having a toner concentration of 5%. This developer was subjected to a printing durability test of 10,000 sheets with CF-900 (manufactured by Minolta), and the images at the initial stage and after 10,000 sheets were examined. Further, the printing durability test of 3,000 sheets was performed on the toner (one-component developer) of Example 5 and Comparative Example 3 with a fine writer 601 (manufactured by Minolta Co.), and the images at the initial stage and after 3,000 sheets were examined. The evaluation was performed by visual judgment, and ranks as “○” when there is no background fog, “△” when there is a background fog but there is no problem in use, and “×” when there is a problem in use. Attached. Since the toners of Example 4 and Comparative Example 2 were not evaluated, the image characteristic evaluation is shown as “−”.

[0083]

[Table 1]

[0084]

[Table 2]

3) Cavity inside toner The amount of cavities inside each toner was determined by microtome adjustment TEM observation. If the amount of cavities is 5% or less, the small particle size component does not increase without breaking the toner during printing,
Excellent image stability.

[0086]

[Table 3]

4) Particle Size Distribution Each toner was measured with a Coulter Multisizer (manufactured by Coulter Inc.) to determine the 50% diameter of the weight distribution and the coefficient of variation.
If the variation coefficient is 35% or less, the particle size distribution is sharp, and an image without fog can be obtained by uniform triboelectric charging.

[0088]

[Table 4]

As is evident from the results, the toners of Examples 1 to 5 and 6 according to the present invention exhibit a sufficient charge rising property and a stable charge amount, and have good images at the initial stage and after the printing test. there were. In Comparative Examples 1 to 4, fog was slightly present from the beginning, fog increased after the printing test, and a change in particle size distribution due to toner collapse was observed.

[0090]

According to the method of the present invention, it is possible to obtain a toner for developing an electrostatic latent image having a small particle diameter, which is excellent in charge rising property and charge stability and has good image characteristics over a long period of time. Further, the toner produced by the method of the present invention has a large amount of the antistatic agent present on the toner surface. Further, the toner of the present invention has few cavities inside the toner and has a sharp particle size distribution.

[Brief description of the drawings]

FIG. 1 shows a schematic configuration diagram of a desolving apparatus preferably used in a step of removing a water-insoluble organic solvent in a method of the present invention.

[Explanation of symbols]

1: Emulsion, 2: Storage tank, 3: Water, 4: Water supply unit, 5: Cooling tower, 6: Collection unit, 7: Recovery unit, 8: Pump, 10: Valve, 11: Vent pipe, 12: Valve, 13: Stirrer, 14:
Vent tube, 15: valve.

Claims (6)

[Claims] 1. A step of dissolving and / or dispersing at least a binder resin and a colorant in a water-insoluble organic solvent to obtain a colored resin solution, and dispersing the colored resin solution with an antistatic agent in an aqueous dispersion. A method for producing a toner for developing an electrostatic latent image, comprising a step of forming an emulsion by emulsifying and dispersing in a liquid, and a step of removing a water-insoluble organic solvent from the emulsion. 2. A step of dissolving and / or dispersing at least a binder resin and a colorant in a water-insoluble organic solvent to obtain a colored resin solution, and an aqueous dispersion in which an antistatic agent is dissolved and / or dispersed in the colored resin solution. A method for producing a toner for developing an electrostatic latent image, comprising a step of adding a liquid and performing phase inversion emulsification to form an emulsion, and a step of removing a water-insoluble organic solvent from the emulsion. 3. A step of dissolving and / or dispersing at least a binder resin and a colorant in a water-insoluble organic solvent to obtain a colored resin solution, and dispersing the colored resin solution in an aqueous dispersion in which an antistatic agent is dissolved and / or dispersed. A toner for developing an electrostatic latent image, which is manufactured through a step of forming an emulsion by emulsifying and dispersing in a liquid, and a step of removing a water-insoluble organic solvent from the emulsion. 4. a step of dissolving and / or dispersing at least a binder resin and a colorant in a water-insoluble organic solvent to obtain a colored resin solution; and an aqueous dispersion in which an antistatic agent is dissolved and / or dispersed in the colored resin solution. A toner for developing an electrostatic latent image, which is manufactured through a step of forming an emulsion by adding a liquid and performing phase inversion emulsification, and a step of removing a water-insoluble organic solvent from the emulsion. 5. An electrostatic latent image developing toner comprising at least a binder resin and a colorant, and having at least an antistatic agent on its surface in the form of fine particles or a coat layer. 6. An electrostatic latent image developing toner comprising at least a binder resin and a colorant, wherein at least an antistatic agent and a charge control agent are present on the surface in the form of fine particles or a coat layer, respectively.