JP5863453B2 - Method for producing emulsion aggregation toner - Google Patents

Description

  The present invention relates to an emulsion aggregation toner for developing an electrostatic image used in an electrophotographic system.

  In recent years, with changes in the usage environment, the colorization rate of copying machines, printers, etc. has been increasing year by year. At the same time, with the demand for high resolution and high gradation and high image quality, it is essential to reduce the toner particle size and sharpen the distribution. Under such circumstances, in the toner manufacturing method, various toner manufacturing methods by a wet method such as an emulsion aggregation method and a polymerization method called a “chemical toner” are attracting attention from the conventional pulverization method. Among them, the emulsion aggregation method using a polyester resin has attracted attention because it is easy to reduce the particle size and spheroidization of the toner. The emulsion aggregation method is a resin particle dispersion produced by a method such as dispersion emulsification or emulsion polymerization of a resin, a color material particle dispersion produced by dispersing a color material in an aqueous medium, and as necessary. This is a method of obtaining an electrophotographic toner by aggregating other components to obtain aggregated particles and then fusing the aggregated particles (see, for example, Patent Documents 1 to 3).

  On the other hand, with increasing demand for energy saving during image formation, efforts have been made to lower the toner fixing temperature. As one of them, it has been proposed to further lower the fixing temperature by using a polyester resin having a low softening temperature. However, since the softening temperature is low, blocking may occur in which toners adhere to each other in a stationary state such as during storage or transportation.

  In addition, when a toner using a polyester resin is produced by a wet method, it is known that the ester bond of the polyester resin is hydrolyzed in a solution and the storage stability of the obtained toner is deteriorated. Accordingly, hydrolysis resistant polyester resins have been proposed in order to improve the storage stability of the toner (Patent Documents 4 and 5).

Japanese Patent Laid-Open No. 63-282275 JP-A-6-250439 JP 2002-351140 A JP 2001-261797 A JP 2007-248582 A

  As a result of our study, it was confirmed that when a polyester toner is produced by an emulsification aggregation method that is a wet manufacturing method, the polyester resin is hydrolyzed during emulsification of resin fine particles and at the time of aggregation of resin fine particles, and the monomer component increases. Moreover, it was confirmed that even if a hydrolysis-resistant resin as in Patent Document 4 or Patent Document 5 is used, an increase in monomers due to hydrolysis cannot be completely suppressed.

  However, it was confirmed that, among the monomer components generated by hydrolysis, the dicarboxylic acid component is highly water-soluble, so it flows out into the aqueous medium, is removed in the washing step, and does not easily remain in the toner. On the other hand, it was confirmed that most of the generated diol component, particularly the aromatic diol component, remained in the toner because of its low water solubility and high boiling point. Furthermore, it was confirmed that the storage stability deteriorates when a diol component as a monomer is present in the toner.

  Further, it was confirmed that when the polyester resin fine particles were emulsified without using an organic solvent in an aqueous system, hydrolysis is more likely to occur and the storage stability of the toner may be greatly deteriorated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing an emulsion aggregation toner that suppresses the residual monomer in the toner and is excellent in storage stability and low-temperature fixability.

The method for producing the emulsion aggregation toner of the present invention comprises:
A mixture of resin fine particles containing a polyester resin emulsified in an aqueous medium , colorant fine particles and release agent fine particles is heated to a temperature not higher than the glass transition temperature of the polyester resin, and the pH of the mixed solution is adjusted to 8 or more. Agglomeration step of aggregating the resin fine particles, the colorant fine particles and the release agent fine particles to obtain an aggregate;
A step of fusing the agglomerates to a temperature above the glass transition temperature of the polyester resin and fusing them to obtain particles having a smooth surface of the agglomerates;
A washing step of washing particles with a smooth surface of the aggregate with water;
A method for producing an emulsion aggregation toner having
The volume-based median diameter of the resin fine particles is 0.05 to 1.0 μm,
The volume-based median diameter of the aggregate is 4.0 to 7.0 μm;
The resin fine particles are resin fine particles containing 50 parts by mass or more of the polyester resin with respect to 100 parts by mass of the resin fine particles,
The polyester resin includes a monomer unit derived from an aromatic hydroxycarboxylic acid.

  According to the present invention, it is possible to provide an emulsion aggregation toner that suppresses the residual monomer in the toner and is excellent in storage stability and low-temperature fixability.

  First, the fine particles used in the present invention will be described.

<Resin fine particles>
The resin fine particles used in the present invention can be obtained by emulsifying resin fine particles mainly composed of a polyester resin containing an aromatic hydroxycarboxylic acid as a monomer component in an aqueous medium. Here, the main component means that 50 parts by mass or more of 100 parts by mass of the resin fine particles are included.

  Any polyester resin can be used as long as it is a polyester resin containing an aromatic hydroxycarboxylic acid as a monomer component. Preferably, the polyester resin contains 50 mol% or more of an aromatic hydroxycarboxylic acid as a monomer unit. Preferably there is. Polyester resin fine particles containing 50 mol% or more of aromatic hydroxycarboxylic acid tend to achieve both low-temperature fixability and storage stability when used as a toner. The reason for this is not clear, but it is considered that since the aromatic hydroxycarboxylic acid has an aromatic ring, the glass transition temperature (Tg) is increased even at a low molecular weight, so that both low temperature fixability and storage stability are easily achieved. In addition, since the aromatic hydroxycarboxylic acid has a carboxyl group, it is difficult to remain in the toner for the reasons described later, and it is considered that the storage stability is improved. The amount of residual monomer in the toner can be measured by dissolving the toner in tetrahydrofuran and liquid chromatography or gas chromatography.

  The aromatic hydroxycarboxylic acid refers to a compound having an aromatic ring and having at least one carboxyl group and one hydroxyl group. Representative aromatic hydroxycarboxylic acid compounds are exemplified below, but are not limited thereto.

  Among these, aromatic hydroxycarboxylic acids that dissolve in water in a state where the carboxyl group is a sodium salt or a potassium salt are preferred. The dissolution means that the solubility in water is 1 g / 100 g or more. The aromatic hydroxycarboxylic acid generated by hydrolysis during emulsion aggregation is converted into a salt by a cation in the system, and if the aromatic hydroxycarboxylic acid salt is soluble, it flows out into the aqueous medium. Therefore, the storage stability is improved without remaining in the toner. An aromatic hydroxycarboxylic acid in which a hydroxyl group is bonded to an aromatic ring via an alkyl group or an alkylene oxide group is preferable. When the hydroxyl group is directly bonded to the aromatic ring, the reactivity of the hydroxyl group becomes low and the synthesis of the polyester resin becomes difficult.

  Further, in order to control physical properties such as Tg and softening temperature of the toner, in addition to the aromatic hydroxycarboxylic acid, other monomeric components such as other hydroxycarboxylic acids, carboxylic acid compounds, and alcohol compounds may be included as monomer components. .

  Other hydroxycarboxylic acids include hydroxyoctanoic acid, hydroxynonanoic acid, hydroxydecanoic acid, hydroxyundecanoic acid, hydroxydodecanoic acid, hydroxytetradecanoic acid, hydroxytridecanoic acid, hydroxyhexadecanoic acid, hydroxypentadecanoic acid, hydroxystearic acid, etc. However, it is not limited to these.

  Examples of carboxylic acid compounds include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, n-dodecyl succinic acid, and n-dodecenyl succinic acid. Aliphatic dicarboxylic acids such as acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid; 1,1-cyclopentenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1, Alicyclic dicarboxylic acids such as 3-adamantane dicarboxylic acid; phthalic acid, isophthalic acid, terephthalic acid, p-phenylenediacetic acid, m-phenylenediacetic acid, p-phenylenedipropionic acid, m-phenylenedipropionic acid, Naphthalene-1,4-dicarboxylic acid Aromatic dicarboxylic acids such as naphthalene-1,5-dicarboxylic acid and naphthalene-2,6-dicarboxylic acid; trimellitic acid, pyromellitic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, pyrenetetracarboxylic acid And trivalent or higher polyvalent carboxylic acids. However, the monomer component is not limited to these.

  Examples of the alcohol compound include 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8 -Divalent alcohols such as octanediol, neopentyl glycol, 1,4-butenediol, cyclohexanediol, and cyclohexanedimethanol. Examples of the trivalent or higher alcohol include glycol, pentaerythritol, hexamethylol melamine, and hexaethylol melamine. However, the monomer component is not limited to these.

  Further, it is more preferable that no aromatic diol is contained as a monomer component of the polyester resin. When the aromatic diol is contained as a monomer component, the aromatic diol generated by hydrolysis remains in the toner, and the storage stability is deteriorated. Here, the aromatic diol is an aromatic diol having no carboxyl group. Specific examples include bisphenol A, bisphenol C, bisphenol E, bisphenol F, bisphenol P, bisphenol S, bisphenol Z, biphenol, naphthalenediol, hydroquinone, and derivatives of these compounds.

  The polyester resin preferably has an ionic group such as a carboxylic acid group, a sulfonic acid group, or an amino group in the resin skeleton, and more preferably has a carboxylic acid group. The acid value is preferably 3 to 35 mgKOH / g, more preferably 8 to 25 mgKOH / g. When the acid value exceeds 35 mgKOH / g, the charge-up in a low humidity environment tends to be remarkable. On the other hand, when the acid value is less than 3 mgKOH / g, the chargeability is low and it is not suitable for toner use. The acid value is the number of mg of potassium hydroxide required to neutralize free fatty acids, resin acids, etc. contained in 1 g of a sample. The measurement method is as follows according to JIS-K0070.

  The glass transition point (Tg) of the polyester resin is preferably 30 ° C. or higher and 60 ° C. or lower, and more preferably 40 ° C. or higher and 60 ° C. or lower. When the Tg is less than 30 ° C., the strength of the entire toner particles is lowered, and the transferability is deteriorated and toner conveyance unevenness is liable to be caused during the durability test. Further, the toner particles are likely to aggregate in a high-temperature and high-humidity environment, resulting in a problem that uneven conveyance is likely to occur. If it is higher than 60 ° C., the glossiness of the image when fixing at a low temperature is deteriorated. In addition, the said glass transition temperature (Tg) is a physical-property value measured based on JISK7121, and means the midpoint glass transition temperature described in this specification.

  The softening temperature (Tm) of the polyester resin is preferably 70 ° C. or higher and 110 ° C. or lower, more preferably 70 ° C. or higher and 100 ° C. or lower, and most preferably 80 ° C. or higher and 100 ° C. or lower. When Tm is less than 70 ° C., the blocking resistance is weak, and even when a release agent is contained, high offset resistance cannot be expected. Further, at a high temperature, the toner melt component becomes noticeable at the time of fixing, and the surface smoothness is impaired. When it is higher than 110 ° C., the fixing property is deteriorated. The softening temperature (Tm) is measured using a flow tester (CFT-500D: manufactured by Shimadzu Corporation). Specifically, 1.2 g of a sample to be measured is weighed, a die having a height of 1.0 mm and a diameter of 1.0 mm is used, a heating rate of 4.0 ° C./min, a preheating time of 300 seconds, a load of 5 kg ( 49N), and measurement is performed under conditions of a measurement temperature range of 60 to 200 ° C. The temperature at which 1/2 of the sample flows out is defined as the softening temperature.

<Colorant fine particles>
The color material fine particles are obtained by dispersing a color material in an aqueous medium. The coloring material is dispersed by a known method. For example, a media type dispersing machine such as a rotary shearing homogenizer, a ball mill, a sand mill, or an attritor, a high-pressure counter collision type dispersing machine, or the like is preferably used. Further, a surfactant or a polymer dispersant that imparts dispersion stability can be added as necessary.

  Examples of the color material include known organic pigments or oil-based dyes, carbon black, and magnetic powder.

  Examples of cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like. Specifically, C.I. I. Pigment blue 1, C.I. I. Pigment blue 7, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. And CI Pigment Blue 66.

  Examples of magenta colorants include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment violet 19, C.I. I. Pigment red 23, C.I. I. Pigment red 48: 2, C.I. I. Pigment red 48: 3, C.I. I. Pigment red 48: 4, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 81: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 144, C.I. I. Pigment red 146, C.I. I. Pigment red 166, C.I. I. Pigment red 169, C.I. I. Pigment red 177, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment red 202, C.I. I. Pigment red 206, C.I. I. Pigment red 220, C.I. I. Pigment red 221, C.I. I. And CI Pigment Red 254.

  Examples of yellow color materials include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and compounds represented by allylamide compounds. Specifically, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 62, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 111, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 127, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 147, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 168, C.I. I. Pigment yellow 174, C.I. I. Pigment yellow 175, C.I. I. Pigment yellow 176, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 181, C.I. I. Pigment yellow 191, C.I. I. And CI Pigment Yellow 194.

  Examples of the black color material include carbon black, magnetic powder, or a material that is toned in black using the yellow, magenta, and cyan color materials.

  These coloring materials can be used alone or in combination, and further in a solid solution state. The color material used in the present invention is selected from the viewpoints of hue angle, saturation, brightness, light resistance, OHP transparency, and dispersibility in toner.

  In the present invention, the content of cyan, magenta, yellow, or black color is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the resin fine particles. If the amount is less than 1 part by mass, color development may be insufficient. If the amount exceeds 20 parts by mass, the color material that is not included in the toner particles tends to increase.

<Partner fine particles>
The release agent fine particles are obtained by dispersing a release agent in an aqueous medium. The releasing agent is dispersed by a known method. For example, a media type dispersing machine such as a rotary shearing type homogenizer, a ball mill, a sand mill, or an attritor, a high-pressure opposed collision type dispersing machine, or the like is preferably used. Further, a surfactant or a polymer dispersant that imparts dispersion stability can be added as necessary.

  Examples of the release agent include low molecular weight polyolefins such as polyethylene; silicones having a melting point (softening point) upon heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide; Ester waxes such as stearyl stearate; plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax And mineral / petroleum waxes such as Fischer-Tropsch wax and ester wax; and modified products thereof.

  The release agent preferably has a melting point of 150.0 ° C. or lower, more preferably 40.0 ° C. or higher and 130.0 ° C. or lower, particularly preferably 40.0 ° C. or higher and 110.0 ° C. or lower. preferable.

  The release agent fine particles are preferably used in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the resin fine particles.

  Next, an emulsion aggregation method that is a method for producing the toner of the present invention will be described.

  The emulsion aggregation method is a production method in which core particles are produced by preparing resin particles sufficiently small in advance with respect to a target particle diameter and aggregating the resin particles in an aqueous medium. In the emulsion aggregation method, toner is manufactured through an emulsification process, an aggregation process, a fusion process, a cooling process, and a washing process of resin fine particles. If necessary, a shelling process may be added after the cooling process to obtain a core-shell toner.

<Emulsification process of resin fine particles>
Resin fine particles mainly composed of a polyester resin containing an aromatic hydroxycarboxylic acid as a monomer component can be prepared by a known method. For example, by dissolving the resin in an organic solvent and adding it to an aqueous medium, dispersing the particles in an aqueous medium with a dispersing agent such as a homogenizer together with a surfactant and a polymer electrolyte, and then removing the solvent by heating or decompressing, A resin particle dispersion can be prepared. Any organic solvent can be used as long as it dissolves the resin, but tetrahydrofuran, ethyl acetate, chloroform and the like are preferable from the viewpoint of solubility.

  In addition, the resin, a surfactant, a base, and the like are added to an aqueous medium, and the mixture is emulsified and dispersed in an aqueous medium substantially free of an organic solvent by a disperser that applies high-speed shearing force such as CLEARMIX, homomixer, and homogenizer. Is preferable from the viewpoint of environmental load. In particular, the content of the organic solvent having a boiling point of 100 ° C. or lower is preferably 100 μg / g or lower. When the amount is outside the above range, a new process for removing and collecting the organic solvent is required when the toner is produced, which imposes a load on wastewater treatment measures. The content of the organic solvent in the aqueous medium can be measured using gas chromatography (GC).

  During this emulsification step, the polyester resin generates monomers by hydrolysis. In particular, when the emulsion is emulsified in a system that does not contain an organic solvent, the generation of monomers becomes more prominent. However, in the case of a polyester resin containing an aromatic hydroxycarboxylic acid as a monomer component, the carboxyl of the generated aromatic hydroxycarboxylic acid is a carboxyl. The group becomes a salt by the cation in the system and flows out into the aqueous medium. Therefore, the generated monomer does not remain in the fine particles.

  In the emulsification step, the pH in the aqueous medium is preferably 8 or more. By setting the pH to 8 or more, most of the hydroxycarboxylic acid, which is a monomer component generated during emulsification, can be converted into a salt and easily removed in an aqueous medium. Any base can be used to adjust the pH, but sodium hydroxide or potassium hydroxide is preferred from the viewpoint of the solubility of the aromatic hydroxycarboxylate.

  The surfactant used at the time of emulsification is not particularly limited, and examples thereof include anionic surfactants such as sulfate ester, sulfonate, carboxylate, phosphate, and soap; Examples thereof include cationic surfactants such as amine salt type and quaternary ammonium salt type; nonionic surfactants such as polyethylene glycol type, alkylphenol ethylene oxide adduct type, and polyhydric alcohol type. The said surfactant may be used individually by 1 type, and may use 2 or more types together.

  The volume-based median diameter of the resin fine particles is preferably 0.05 to 1.0 μm, more preferably 0.05 to 0.4 μm. If it exceeds 1.0 μm, it is difficult to obtain toner particles having a volume-based median diameter of 4.0 to 7.0 μm, which are suitable as toner particles. The volume-based median diameter can be measured by using a dynamic light scattering particle size distribution meter (Nanotrack UPA-EX150: manufactured by Nikkiso Co., Ltd.).

<Aggregation process>
The agglomeration step refers to mixing the above-mentioned resin fine particles, colorant fine particles, and release agent fine particles as necessary to prepare a mixed solution, and then aggregating the particles contained in the prepared mixed solution, Is a step of forming. As a method for forming the agglomerates, for example, a method in which a flocculant is added and mixed in the above mixed solution, and a temperature, mechanical power, and the like are appropriately added can be preferably exemplified.

  Examples of the flocculant include metal salts of monovalent metals such as sodium and potassium; metal salts of divalent metals such as calcium and magnesium; metal salts of trivalent metals such as iron and aluminum.

  The addition / mixing of the flocculant is preferably performed at a temperature not higher than the glass transition temperature (Tg) of the resin particles contained in the mixed solution. When the above mixing is performed under this temperature condition, aggregation proceeds in a stable state. The said mixing can be performed using a well-known mixing apparatus, a homogenizer, a mixer, etc.

  The average particle diameter of the aggregate formed here is not particularly limited, but it is usually preferable to control the average particle diameter to 4.0 μm to 7.0 μm so as to be the same as the average particle diameter of the toner particles to be obtained. Control can be easily performed, for example, by appropriately setting and changing the temperature at the time of addition / mixing of the flocculant and the like and the conditions of the stirring and mixing. The particle size distribution of the toner particles can be measured with a particle size distribution analyzer (Coulter Multisizer III: manufactured by Coulter, Inc.) using a Coulter method.

  Moreover, it is preferable to make pH in an aqueous medium into 8 or more from a viewpoint of dissolving and removing the monomer which generate | occur | produces by hydrolysis of a polyester resin in an aqueous medium similarly to an emulsification process. When the pH is less than 8, it is not preferable because the monomer that has flowed into the aqueous medium in the emulsification step may be precipitated and taken into the toner.

<Fusion process>
The fusing step is a step of producing particles in which the agglomerate surface is smoothed by heating and fusing the agglomerates above the glass transition point (Tg) of the resin. Before entering the primary fusing step, a chelating agent, a pH adjusting agent, a surfactant and the like can be appropriately added in order to prevent fusion between toner particles.

  Examples of chelating agents include alkali metal salts such as ethylenediaminetetraacetic acid (EDTA) and its Na salt, sodium gluconate, sodium tartrate, potassium citrate and sodium citrate, both nitrotriacetate (NTA) salts, COOH and OH There are many water-soluble polymers (polyelectrolytes) that contain the following functionalities.

  The heating temperature may be between the glass transition temperature (Tg) of the resin contained in the aggregate and the temperature at which the resin is thermally decomposed. As the heating / fusion time, a short time is sufficient if the heating temperature is high, and a long time is required if the heating temperature is low. That is, the heating / fusion time depends on the temperature of heating and cannot be defined unconditionally, but is generally 10 minutes to 10 hours.

<Cooling process>
The cooling step is a step of cooling the temperature of the aqueous medium containing the particles to a temperature lower than the glass transition point (Tg) of the core resin. If the cooling is not performed to a temperature lower than Tg, coarse particles are generated. The specific cooling rate is 0.1 to 50 ° C./min.

<Shelling process>
In the present invention, if necessary, a shelling step can be added before the following washing and drying step. The shelling step is a step of newly adding resin fine particles to the particles produced in the previous steps and attaching them to form a shell.

  The binder resin fine particles added here may have the same structure as the binder resin fine particles used for the core, or may be binder resin fine particles having a different structure.

  The resin constituting such a shell layer is not particularly limited, and known resins used for toners, for example, vinyl polymers such as polyester resins and styrene-acrylic copolymers, epoxy resins, polycarbonate resins, and polyurethane resins. Etc. can be used. Of these, a polyester resin or a styrene-acrylic copolymer is preferable, and a polyester resin is more preferable from the viewpoints of fixability and durability. A polyester resin has a lower molecular weight than a vinyl polymer because it has flexibility compared to a vinyl polymer such as a styrene-acrylic copolymer when it has a rigid aromatic ring in the main chain. Can provide equivalent mechanical strength. Therefore, a polyester resin is preferable as a resin suitable for low-temperature fixability.

  In the present invention, the binder resin constituting the shell layer may be used alone or in combination of two or more.

<Washing and drying process>
An emulsion aggregation toner can be obtained by washing, filtering, drying and the like of the particles produced through the above steps. It is preferable to carry out washing filtration with ion-exchanged water whose pH is adjusted with sodium hydroxide or potassium hydroxide, and then washing and filtering with ion-exchanged water several times. By performing washing by this method, the monomer component generated by hydrolysis can be efficiently removed.

  Then, drying is performed, and if necessary, shearing force is applied in a dry state to inorganic particles such as silica, alumina, titania, calcium carbonate, and resin particles such as vinyl resin, polyester resin, and silicone resin. It may be added. These inorganic particles and resin particles function as external additives such as fluidity aids and cleaning aids.

  Hereinafter, although the present invention is explained still in detail using an example and a comparative example, the mode of the present invention is not limited to these.

<Manufacture of monomer>
300 parts by mass of potassium hydroxide is dissolved in a mixed solution of 700 parts by mass of ethanol and 300 parts by mass of water, and 280 parts by mass of 4-hydroxybenzoic acid and a catalytic amount of potassium iodide are dissolved in the solution. Then, 180 parts by mass of ethylene chlorohydrin was gradually added and refluxed for about 15 hours. Ethanol was distilled off from the obtained reaction liquid, and then it was put in 2 L of water. This aqueous solution was washed twice with diethyl ether, and hydrochloric acid was added to make an acidic liquid. Further, the precipitate was filtered and dried, and then recrystallized with ethanol to obtain 4- (2-hydroxyethoxy) benzoic acid. Also. The obtained 4- (2-hydroxyethoxy) benzoic acid was neutralized with sodium hydroxide and dissolved in water.

<Manufacture of polyester resin 1>
4- (2-hydroxyethoxy) benzoic acid 96 mol%
Trimellitic acid 4 mol%
Into a well-heated and dried two-necked flask, add the above components, add 0.05 parts by mass of dibutyltin oxide to 100 parts by mass of the above mixture, and introduce nitrogen gas into the container while maintaining an inert atmosphere. After raising the temperature, a copolycondensation reaction was carried out at 230 ° C. for about 12 hours. Thereafter, the pressure was reduced, the temperature was raised to 250 ° C., and a copolycondensation reaction was further performed for 4 hours to synthesize polyester resin 1 (Tg: 69 ° C., Tm: 109 ° C.).

<Manufacture of polyester resin 2>
4- (2-hydroxyethoxy) benzoic acid 40 mol%
Polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane
30 mol%
Terephthalic acid 18 mol%
Fumaric acid 8 mol%
Trimellitic acid 4 mol%
Into a well-heated and dried two-necked flask, add the above components, add 0.05 parts by mass of dibutyltin oxide to 100 parts by mass of the above mixture, and introduce nitrogen gas into the container while maintaining an inert atmosphere. After raising the temperature, a copolycondensation reaction was carried out at 230 ° C. for about 12 hours. Thereafter, the pressure was reduced, the temperature was raised to 250 ° C., and a copolycondensation reaction was further performed for 4 hours to synthesize polyester resin 2 (Tg: 60 ° C., Tm: 110 ° C.).

<Manufacture of polyester resin 3>
4- (2-hydroxyethoxy) benzoic acid 40 mol%
Ethylene glycol 30 mol%
Terephthalic acid 18 mol%
Miley acid 8mol%
Trimellitic acid 4 mol%
Into a well-heated and dried two-necked flask, add the above components, add 0.05 parts by mass of dibutyltin oxide to 100 parts by mass of the above mixture, and introduce nitrogen gas into the container while maintaining an inert atmosphere. After raising the temperature, a copolycondensation reaction was carried out at 230 ° C. for about 12 hours. Thereafter, the pressure was reduced, the temperature was raised to 250 ° C., and a copolycondensation reaction was further performed for 4 hours to synthesize polyester resin 3 (Tg: 65 ° C., Tm: 108 ° C.).

<Manufacture of polyester resin 4>
Polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane
25 mol%
Polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane
25 mol%
26 mol% terephthalic acid
Fumaric acid 20 mol%
Trimellitic acid 4 mol%
Into a well-heated and dried two-necked flask, add the above components, add 0.05 parts by mass of dibutyltin oxide to 100 parts by mass of the above mixture, and introduce nitrogen gas into the container while maintaining an inert atmosphere. After raising the temperature, a copolycondensation reaction was carried out at 230 ° C. for about 12 hours. Thereafter, the pressure was reduced, the temperature was raised to 250 ° C., and a copolycondensation reaction was further performed for 2 hours to synthesize polyester resin 4 (Tg: 54 ° C., Tm: 109 ° C.).

<Manufacture of polyester resin 5>
Polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane
25 mol%
Polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane
25 mol%
26 mol% terephthalic acid
14 mol% fumaric acid
Trimellitic acid 10 mol%
Into a well-heated and dried two-necked flask, add the above components, add 0.05 parts by mass of dibutyltin oxide to 100 parts by mass of the above mixture, and introduce nitrogen gas into the container while maintaining an inert atmosphere. After raising the temperature, a copolycondensation reaction was carried out at 230 ° C. for about 12 hours. Thereafter, the pressure was reduced, the temperature was raised to 250 ° C., and a copolycondensation reaction was further performed for 7 hours to synthesize polyester resin 5 (Tg: 55 ° C., Tm: 141 ° C.).

<Manufacture of polyester resin 6>
Polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane
35 mol%
Ethylene glycol 15 mol%
Terephthalic acid 33 mol%
Maleic acid 15 mol%
Trimellitic acid 2 mol%
Into a well-heated and dried two-necked flask, add the above components, add 0.05 parts by mass of dibutyltin oxide to 100 parts by mass of the above mixture, and introduce nitrogen gas into the container while maintaining an inert atmosphere. After raising the temperature, a copolycondensation reaction was carried out at 230 ° C. for about 12 hours. Thereafter, the pressure was reduced, the temperature was raised to 250 ° C., and a copolycondensation reaction was further performed for 3 hours to synthesize polyester resin 6 (Tg: 65 ° C., Tm: 126 ° C.).

<Manufacture of polyester resin 7>
Lactic acid lactide 97 mol%
Ethylene glycol 3 mol%
Into a well-heated and dried two-necked flask, add the above components, add 0.05 parts by mass of dibutyltin oxide to 100 parts by mass of the above mixture, and introduce nitrogen gas into the container while maintaining an inert atmosphere. After raising the temperature, a copolycondensation reaction was carried out at 160 ° C. for about 8 hours. Thereafter, the pressure was reduced, and a copolycondensation reaction was further performed for 5 hours to synthesize polyester resin 7 (Tg: 56 ° C., Tm: 170 ° C.).

(Production of resin fine particles 1)
Sulfonic acid anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) 0.75 part by mass and N, N-dimethylaminoethanol (basic substance) 3.15 parts by mass, ion-exchanged water (aqueous medium) A dispersion medium liquid was prepared by dissolving in 146.10 parts by mass. This dispersion medium liquid was put in a pressure-resistant round bottom stainless steel container, and then 150 parts by mass of “polyester resin 1” was added and mixed.

  Next, a high-speed shearing emulsifier CLEARMIX (M Technique Co., Ltd .: CLM-2.2S) was hermetically connected to the pressure-resistant round bottom stainless steel container. While heating and pressurizing the mixture in the container to 140 ° C. and 0.18 MPa, the Claremix rotor was rotated at 18,000 r / min for 30 minutes for shear dispersion. Thereafter, cooling was performed at a cooling rate of 2.0 ° C./min while maintaining a rotation of 18,000 r / min until 50 ° C., and an emulsion of resin fine particles 1 was obtained. The volume-based median diameter was 0.25 μm as measured using a dynamic light scattering particle size distribution diameter (Nanotrack: manufactured by Nikkiso Co., Ltd.).

(Manufacture of resin fine particles 2)
Except that the polyester resin 1 was changed to the polyester resin 2, an emulsion of the resin fine particles 2 was obtained in the same manner as the method for producing the resin fine particles 1 (volume-based median diameter 0.27 μm).

(Production of resin fine particles 3)
Except that the polyester resin 1 was changed to the polyester resin 3, an emulsion of the resin fine particles 3 was obtained in the same manner as the method for producing the resin fine particles 1 described above (volume-based median diameter 0.25 μm).

(Production of resin fine particles 4)
Dissolve 0.3 parts by mass of a sulfonic acid anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) and 1.9 parts by mass of N, N-dimethylaminoethanol (basic substance) in 200 parts by mass of tetrahydrofuran. I let you. Subsequently, 60 parts by mass of polyester resin 3 was dissolved. K. The mixture was stirred at 4000 r / min using Robomix (Primix). Further, 177.8 parts by mass of ion-exchanged water was added dropwise, and then tetrahydrofuran was removed using an evaporator to obtain an emulsion of resin fine particles 4 (volume-based median diameter 0.15 μm).

(Production of resin fine particles 5)
An emulsion of resin fine particles 5 was obtained in the same manner as the resin fine particle 1 production method except that the polyester resin 1 was changed to the polyester resin 4 (volume-based median diameter 0.38 μm).

(Production of resin fine particles 6)
Except that the polyester resin 3 was changed to the polyester resin 4, an emulsion of the resin fine particles 6 was obtained in the same manner as the method for producing the resin fine particles 4 (volume-based median diameter 0.08 μm).

(Production of resin fine particles 7)
Except that the polyester resin 1 was changed to the polyester resin 5, an emulsion of the resin fine particles 7 was obtained in the same manner as the method for producing the resin fine particles 1 (volume-based median diameter 0.20 μm).

(Production of resin fine particles 8)
Except that the polyester resin 1 was changed to the polyester resin 6, an emulsion of the resin fine particles 8 was obtained in the same manner as the method for producing the resin fine particles 1 (volume-based median diameter 0.35 μm).

(Production of resin fine particles 9)
An emulsion of resin fine particles 9 was obtained (volume-based median diameter 0.21 μm) in the same manner as in the method for producing resin fine particles 1 except that the polyester resin 1 was changed to the polyester resin 7.

(Manufacture of color material fine particles)
10 parts by weight of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) 88.5 parts by weight of ion-exchanged water (Cyan pigment, manufactured by Dainichi Seika Co., Ltd .: Pigment Blue 15: 3) The mixture was dissolved, dissolved, and dispersed for about 1 hour using a high-pressure impact disperser Nanomizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.) to prepare an aqueous dispersion of coloring material fine particles obtained by dispersing the coloring material. The volume-based median diameter was measured using a dynamic light scattering particle size distribution diameter (Nanotrack: manufactured by Nikkiso Co., Ltd.), and was 0.20 μm.

(Manufacture of release agent fine particles)
Release agent (behenyl behenate, melting point 75 ° C.) 10 parts by weight anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) 1 part by weight ion-exchanged water 89 parts by weight The above is put into a mixing vessel equipped with a stirrer. After heating to 90 ° C. and circulating to Claremix W Motion (M Technique Co., Ltd.), the rotor rotating speed is 19000 r / min, screen at the shear stirrer where the rotor outer diameter is 3 cm and the clearance is 0.3 mm. The mixture is stirred at a rotational speed of 19000 r / min, dispersed for 60 minutes, and then cooled to 40 ° C. under cooling conditions of a rotor rotational speed of 1000 r / min, a screen rotational speed of 0 r / min, and a cooling rate of 10 ° C./min. Thus, an aqueous dispersion of release agent fine particles was obtained. The volume-based median diameter was measured using a dynamic light scattering particle size distribution diameter (Nanotrack: manufactured by Nikkiso), and was 0.15 μm.

(Example 1 Production of emulsion aggregation toner 1)
Resin fine particle 1 10 parts by mass (resin equivalent)
Colorant fine particles 0.5 parts by mass (equivalent to colorant)
Release agent fine particles 1.0 parts by weight (equivalent to release agent)
1.5 mass% magnesium sulfate aqueous solution 10 mass parts ion-exchanged water Remaining amount 100 mass parts The above was dispersed using a homogenizer (manufactured by IKA: Ultra Turrax T50). Subsequently, the pH was adjusted to 8.1 with a 0.1N sodium hydroxide aqueous solution. Then, it heated, stirring with a stirring blade to 45 degreeC in the water bath for heating. After maintaining at 45 ° C. for 1 hour, observation with an optical microscope confirmed that aggregated particles having an average particle size of about 5.5 μm were formed. After adding 40 parts by mass of a 5 mass% trisodium citrate aqueous solution, the temperature was raised to 85 ° C. while continuing stirring, and maintained for 120 minutes to fuse the core particles. Next, while stirring was continued, water was placed in the water bath and cooled to 25 ° C. Further, when the particle size of the core particles was measured by a particle size distribution analyzer (Coulter Multisizer III: manufactured by Coulter, Inc.) by the Coulter method, the volume-based median diameter was 5.5 μm.

  Thereafter, after filtration and solid-liquid separation, 800 parts by mass of ion-exchanged water whose pH was adjusted to 8 with sodium hydroxide was added to the solid content, followed by stirring and washing for 30 minutes. Thereafter, filtration and solid-liquid separation were performed again. Subsequently, 800 parts by mass of ion-exchanged water was added to the solid content and washed with stirring for 30 minutes. Thereafter, filtration and solid-liquid separation were performed again, and this was repeated 5 times. Next, by drying the obtained solid content, the emulsion aggregation toner of Example 1 could be obtained.

(Example 2 Production of emulsion aggregation toner 2)
An emulsion aggregation toner 2 of Example 2 was obtained in the same manner as in the method for producing the emulsion aggregation toner 1 except that the resin particles 1 were changed to the resin particles 2.

(Example 3 Production of emulsion aggregation toner 3)
An emulsion aggregation toner 3 of Example 3 was obtained in the same manner as in the method for producing the emulsion aggregation toner 1 except that the resin particles 1 were changed to the resin particles 3.

( Reference Example 4 Production of emulsion aggregation toner 4)
Without pH adjustment with 0.1N sodium hydroxide aqueous solution, except that the condition of p H6.5, similarly to the method of manufacturing the emulsion aggregation toner 3 was obtained emulsion aggregation toner 4 of Reference Example 4 .

Example 5 Production of emulsion aggregation toner 5
An emulsion aggregation toner 5 of Example 5 was obtained in the same manner as in the method for producing the emulsion aggregation toner 1 except that the resin particles 1 were changed to the resin particles 4.

(Comparative Example 1 Production of emulsion aggregation toner 6)
An emulsion aggregation toner 6 of Comparative Example 1 was obtained in the same manner as in the method for producing the emulsion aggregation toner 1 except that the resin particles 1 were changed to the resin particles 5.

(Comparative Example 2 Production of emulsion aggregation toner 7)
An emulsion aggregation toner 7 of Comparative Example 2 was obtained in the same manner as in the method for producing the emulsion aggregation toner 1 except that the resin particles 1 were changed to the resin particles 6.

(Comparative Example 3 Production of emulsion aggregation toner 8)
An emulsion aggregation toner 8 of Comparative Example 3 was obtained in the same manner as in the method for producing the emulsion aggregation toner 1 except that the resin particles 1 were changed to the resin particles 7.

(Comparative Example 4 Production of Emulsion Aggregated Toner 9)
An emulsion aggregation toner 9 of Comparative Example 4 was obtained in the same manner as in the method for producing the emulsion aggregation toner 1 except that the resin particles 1 were changed to the resin particles 8.

(Comparative Example 5 Production of emulsion aggregation toner 10)
An emulsion aggregation toner 10 of Comparative Example 5 was obtained in the same manner as in the method for producing the emulsion aggregation toner 1 except that the resin particles 1 were changed to the resin particles 9.

The following evaluation was performed using the emulsion aggregation toners of Examples 1 to 3, Reference Example 4, Example 5, and Comparative Examples 1 to 5. The results are shown in Table 1.

(Measurement of residual monomer)
After adding 5 parts by mass of tetrahydrofuran to 1 part by mass of toner particles and dispersing and dissolving with ultrasonic waves for 30 minutes, the supernatant liquid is analyzed by liquid chromatography (Prominence, manufactured by Shimadzu Corporation), and residual monomers in the toner particles are analyzed. It was measured. The evaluation results are shown in Table 1.

(Evaluation of low-temperature fixability)
To 100 parts by mass of toner particles, 1.8 parts by mass of hydrophobized silica fine powder having a specific surface area measured by the BET method of 200 m ² / g was dry-mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.). An additive toner was obtained. Each externally added toner and a ferrite carrier surface-coated with a silicone resin (average particle size 42 μm) were mixed to a toner concentration of 6% by mass to prepare a two-component developer. A commercially available full color digital copying machine (CLC1100, manufactured by Canon Inc.) was used to form an unfixed toner image (0.6 mg / cm ² ) on the image receiving paper (64 g / m ² ). A fixing unit removed from a commercially available color laser printer (LBP-5500, manufactured by Canon Inc.) was remodeled so that the fixing temperature could be adjusted, and a fixing test of an unfixed image was performed using this. Under normal temperature and normal humidity, the process speed was set to 100 mm / sec, and the cold offset when the unfixed image was fixed was visually evaluated. The evaluation results are shown in Table 1.

[Fixing temperature range where no cold offset occurs]
○: Cold offset occurs at a temperature of 140 ° C or higher.
Or cold offset does not occur ×: Cold offset occurs at temperatures below 140 ° C

(Evaluation of high humidity storage)
Each externally added toner was allowed to stand for 1 week and 2 weeks in a high-temperature and high-humidity tank at 40 ° C. and 95% humidity, and the degree of blocking was evaluated visually. The evaluation results are shown in Table 1.
A: No blocking occurred after 2 weeks.
○: Blocking occurs after 2 weeks, but disperses easily by light vibration.
Δ: Blocking occurs after 2 weeks, but disperses with continued vibration.
X: Blocking occurs after 2 weeks and does not disperse even when force is applied.
XX: Blocking occurs after 1 week and does not disperse even when force is applied.

Claims (8)

An agglomeration step of aggregating resin fine particles containing a polyester resin having a volume-based median diameter of 0.05 to 1.0 μm , colorant fine particles and release agent fine particles to obtain an aggregate ;
A fusion step of heating the aggregate to a temperature above the glass transition temperature of the polyester resin and fusing the aggregate to obtain particles having a smooth surface of the aggregate ;
A washing step of washing particles with a smooth surface of the aggregate with water ;
A method for producing an emulsion aggregation toner having
The resin fine particles are resin fine particles containing 50 parts by mass or more of the polyester resin with respect to 100 parts by mass of the resin fine particles,
The polyester resin includes a monomer unit derived from an aromatic hydroxycarboxylic acid,
The aggregating step includes
A mixture of the resin fine particles emulsified in an aqueous medium, the colorant fine particles and the release agent fine particles is heated to a temperature not higher than the glass transition temperature of the polyester resin, so that the pH of the mixed solution is 8 or more. And agglomerating the resin fine particles, the colorant fine particles and the releasing agent fine particles to obtain an aggregate having a volume-based median diameter of 4.0 to 7.0 μm. A method for producing an emulsion aggregation toner. The polyester resin The production method of emulsion aggregation toner according monomer units derived from the aromatic hydroxycarboxylic acid based on the total monomer units of the polyester resin to claim 1 containing more than 50 mol%. The aromatic hydroxycarboxylic acid, in the state of sodium or potassium salt, solubility in water, the production method of emulsion aggregation toner according to claim 1 or 2 is 1 g / 100 g or more. The method for producing an emulsion aggregation toner according to any one of claims 1 to 3, wherein the aromatic hydroxycarboxylic acid is a compound represented by the following formula (1).

(In the formula (1), R is CH. ₂ , C ₂ H _Four , C _Three H ₆ , OC ₂ H _Four , OC _Three H ₆ , OC ₂ H _Four OC ₂ H _Four , OC _Three H ₆ OC _Three H ₆ Or none. ) Method for producing the emulsion aggregation toner, the polyester resin particles containing a resin as a step for obtaining a form emulsified in an aqueous medium, the polyester resin by adding shearing force to the polyester resin at pH8 or more in the aqueous medium method for producing emulsion aggregation toner according to claim 1, further comprising the emulsifying step Ru is emulsified. The method for producing an emulsion aggregation toner according to claim 1, wherein the water is ion-exchanged water. The method for producing an emulsion aggregation toner according to claim 6, wherein the emulsification step is performed in an aqueous medium having a boiling point of 100 ° C. or less and an organic solvent content of 100 μg / g or less. The method for producing an emulsion aggregation toner according to any one of claims 1 to 7 , wherein the polyester resin does not contain a monomer unit derived from an aromatic diol.