JP4935519B2 - Method for producing toner for developing electrostatic image - Google Patents

Description

  The present invention relates to a method for producing an electrostatic image developing toner for use in electrophotographic copying machines and printers. More specifically, the present invention is mainly characterized by an aging step in which particle aggregates are heated and fused. The present invention relates to a method for producing a toner for developing an electrostatic image.

  In an electrophotographic system, a toner for developing an electrostatic image that has been widely used in general (hereinafter sometimes simply referred to as “toner”) is used for various binder resins such as a styrene-acrylate copolymer and a polyester. It has been produced by melting and kneading a mixture containing a colorant such as carbon black and pigment, and, if necessary, a charge control agent and a magnetic substance with an extruder, followed by pulverization and classification.

  However, the conventional toner obtained by the melt-kneading pulverization method has a limit in controlling the particle size of the toner, and a toner having a volume median diameter (Dv50) of substantially 10 μm or less, particularly 8 μm or less, has a good yield. It is difficult to manufacture and cannot be said to be sufficient to achieve the high resolution required for electrophotography.

  In order to achieve low-temperature fixability, a method has been proposed in which a wax having a low softening point is blended into the toner during kneading, but in the melt-kneading pulverization method, blending of about 5% by weight of wax is the limit. Thus, a toner having sufficient low-temperature fixability could not be obtained. Further, when the flakes obtained by melt-kneading are mechanically pulverized into a toner, the yield is poor and the particle size distribution is wide, particularly when trying to obtain a toner having a small particle size. The trend was remarkable.

  Therefore, in recent years, an emulsion polymerization aggregation method, a suspension polymerization method, and the like have been studied as production methods that replace the melt-kneading and pulverization method. If these methods are used, unlike the melt-kneading pulverization method, it is possible to control the dispersion and content of wax and the like, and it is possible to contain 5% by mass or more of wax. In particular, in the emulsion polymerization aggregation method, the particle size, particle size distribution, toner shape and the like can be controlled.

  When a toner is produced by an emulsion polymerization aggregation method, a pigment, a charge control agent, etc. are added to a dispersion containing polymer primary particles having a volume median diameter (Mv50) of about 0.02 μm to 3 μm obtained by emulsion polymerization. In addition, the polymer primary particles are further aggregated by adding an electrolyte or the like to form aggregated particles of about 3 μm to 9 μm, and then aged at a temperature higher than the glass transition temperature (Tg) of the polymer primary particles, The surface and internal particles are fused together to obtain toner base particles, and finally the toner base particle slurry is washed and dried to obtain toner base particles.

  In this method, in order to increase the stability of the polymer primary particles obtained by polymerization, and to make it easier to control the volume median diameter (Dv50) in the aggregation step, the monomers constituting the polymer primary particles Although it was necessary to include a certain amount or more of a monomer having a polar group, such a toner easily absorbs moisture, has low chargeability, and adversely affects image quality.

  On the other hand, if the content of the monomer having a polar group is decreased in order to solve the above problem, it becomes difficult to control the particle size in the aggregation process, and the temperature is equal to or higher than the glass transition temperature (Tg) of the polymer primary particles. When ripening with, the particle size of the particle aggregate is not stable, and the particle size tends to become unnecessarily large.

  Although the demand for higher image quality has been increasing, as described above, with this technology, it has not been possible to produce toner while maintaining high chargeability and stabilizing particle size control.

JP 2002-304020 A JP-A 63-186253 JP-A-7-146588 JP 2000-347456 A

  In order to solve the above problems, it is effective to add a dispersant such as an emulsifier and a pH regulator before raising the temperature to the glass transition temperature (Tg) or higher. However, it is necessary to add a large amount of the dispersant. In some cases, even when a dispersant is added, the growth of the particle aggregate cannot be suppressed, the particle size of the particle aggregate is not stable, and the above-described problems cannot be solved. Furthermore, since a large amount of dispersant is used in this method, a large amount of washing water is required when washing the final toner base particles, and the waste of washing water increases the burden on the environment. It was also disadvantageous.

  Accordingly, an object of the present invention is to provide a production method for obtaining a small particle size toner having a stabilized particle size, which is suitable for high charging, high image quality, high speed printing, and the like.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by devising the aggregation step and the ripening step of the polymer primary particles, and have reached the present invention.

  That is, the present invention provides an aggregating step of aggregating particles while stirring at least a dispersion containing polymer primary particles and colorant particles to obtain particle agglomerates, and glass transition of the polymer agglomerates of the particle agglomerates. A method for producing a toner for developing an electrostatic image having a ripening step of fusing at a temperature higher than a temperature, wherein the toner is heated while adding a dispersant in the ripening step. The manufacturing method of this is provided.

  The present invention also provides an electrostatic image developing toner produced by the above production method.

  According to the present invention, a small particle size toner having excellent chargeability, image quality performance, low temperature fixability, etc., low toner consumption, and sharp particle size distribution can be used to prevent unnecessary growth of particle aggregates. The volume median diameter (Dv50) can be controlled stably. Further, since the amount of the dispersing agent can be reduced, a small amount of water is required for cleaning the toner base particles, which is advantageous in reducing production costs such as cleaning costs and waste liquid costs as well as reducing the burden on the environment.

  Hereinafter, the present invention will be described. However, the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented.

  The toner manufactured in the toner manufacturing method of the present invention (the toner to be manufactured in the toner manufacturing method of the present invention) contains at least a binder resin and a colorant, and if necessary, a charge control agent, a wax, and the like. Contains additives. In the toner production method of the present invention, the polymer primary particles to be aggregated are produced by a wet polymerization method such as an emulsion polymerization method or a suspension polymerization method. Among them, in the production method of the present invention, an emulsion polymerization aggregation method is preferable in order to achieve a more suitable particle size distribution. The emulsion polymerization aggregation method has an advantage that the circularity of the toner base particles can be appropriately controlled.

  The binder resin used for the toner can be selected from a wide range including conventionally known binder resins. Preferable examples include styrene polymers such as styrene-acrylic acid ester copolymers, styrene-methacrylic acid ester copolymers, and copolymers obtained by further copolymerizing acrylic acid or methacrylic acid. The binder resin is not limited to being used alone, but two or more kinds can be used in combination.

  When the toner is produced by the emulsion polymerization aggregation method, it is preferable to use at least styrene as a copolymer component and further use an alkyl ester of acrylic acid or methacrylic acid as a copolymer component.

  The colorant may be any of inorganic pigments, organic pigments, organic dyes, or a combination thereof. Specific examples of these include carbon black, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow, rhodamine dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, monoazo, disazo. Any known dye / pigment such as a azo dye or condensed azo dye / pigment can be used alone or in combination. In the case of a full-color toner, benzidine yellow, monoazo, condensed azo dyes, etc. as yellow colorants; quinacridone, monoazo dyes, etc. as magenta colorants; phthalocyanine blue, etc. as cyan colorants Each is preferably used.

  Of these, specific examples of cyan colorants include C.I. I. Pigment Blue 15: 3; As a colorant for yellow, C.I. I. Pigment yellow 74, C.I. I. Pigment Yellow 93; C.I. I. Pigment red 238, C.I. I. Pigment red 269, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 48: 2, C.I. I. Pigment Red 122 or the like is preferably used.

  The content of the colorant is preferably in the range of 2 to 25 parts by weight with respect to 100 parts by weight of the binder resin.

  The toner produced by the toner production method of the present invention may contain a charge control agent in order to impart charge amount and charge stability. Conventionally known compounds are used as the charge control agent. Examples thereof include a metal complex of hydroxycarboxylic acid, a metal complex of an azo compound, a naphthol compound, a metal compound of a naphthol compound, a nigrosine dye, a quaternary ammonium salt, or a mixture thereof.

  The content of the charge control agent is preferably in the range of 0.1 to 5 parts by weight with respect to 100 parts by weight of the binder resin.

  The toner produced by the toner production method of the present invention preferably contains a wax for imparting releasability. Any wax can be used as long as it has releasability.

  Specifically, for example, olefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene and copolymer polyethylene; paraffin wax; ester waxes having a long-chain aliphatic group such as behenyl behenate, montanate ester, stearyl stearate A vegetable wax such as hydrogenated castor oil carnauba wax; a ketone having a long chain alkyl group such as distearyl ketone; a silicone having an alkyl group; a higher fatty acid such as stearic acid; a long chain aliphatic alcohol such as eicosanol; Examples include carboxylic acid esters or partial esters of polyhydric alcohols obtained from polyhydric alcohols such as erythritol and long chain fatty acids; higher fatty acid amides such as oleic acid amides and stearic acid amides; low molecular weight polyesters.

  Among these waxes, in order to improve fixability, the melting point of the wax is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and particularly preferably 50 ° C. or higher. Moreover, 100 degrees C or less is preferable, 90 degrees C or less is more preferable, and 80 degrees C or less is especially preferable. If the melting point is too low, the wax may be exposed on the surface after fixing, and stickiness may occur. On the other hand, if the melting point is too high, the fixability at low temperatures may be poor.

  As the wax compound species, higher fatty acid ester waxes are preferable. Specific examples of the higher fatty acid ester wax include, for example, behenyl behenate, stearyl stearate, stearate ester of pentaerythritol, glyceride montanate, and the like, and fatty acids having 15 to 30 carbon atoms and 1 to 5 valent alcohols. The esters are preferred. Moreover, as an alcohol component which comprises ester, a C10-30 thing is preferable in the case of monohydric alcohol, and a C3-C10 thing is preferable in the case of a polyhydric alcohol.

  The above waxes may be used alone or in combination. Further, the melting point of the wax compound can be appropriately selected depending on the fixing temperature for fixing the toner.

  The content of the wax in the toner is usually 0.1 to 40 parts by weight, preferably 1 to 40 parts by weight, more preferably 5 to 35 parts by weight, with respect to 100 parts by weight of the binder resin. The amount is particularly preferably 7 to 30 parts by weight.

  Next, the production of toner by a wet polymerization method such as an emulsion polymerization aggregation method or a suspension polymerization aggregation method will be described.

  In the emulsion polymerization agglomeration method, a dispersion of polymer primary particles is mixed with a colorant dispersion, a wax dispersion, or a charge control agent dispersion if necessary, and the temperature, salt concentration, pH, etc. are appropriately controlled. These are aggregated to produce toner base particles.

  Examples of the emulsifier used for the emulsion polymerization include at least one emulsifier selected from a cationic surfactant, an anionic surfactant, and a nonionic surfactant.

  Specific examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide and the like.

  Specific examples of the anionic surfactant include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate (hereinafter sometimes abbreviated as “DBS”), sodium lauryl sulfate. Etc.

  Specific examples of nonionic surfactants include polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, monodecanoyl Sucrose etc. are mentioned.

  Of these surfactants, alkali metal salts of linear alkylbenzene sulfonic acids are particularly preferred.

  As a polymerization initiator used in the wet polymerization method, known polymerization initiators can be used singly or in combination of two or more. For example, potassium persulfate, 2,2′-azobisisobutyronitrile, 2,2′-azobisiso (2,4-dimethyl) valeronitrile, benzoyl peroxide, lauroyl peroxide, redox initiator, etc. Can be used. Of these, redox initiators are preferred in the emulsion polymerization aggregation method.

  After agglomeration by the above method, as a encapsulation step, a resin fine particle dispersion (polymer emulsion), a colorant dispersion, a charge control agent dispersion, a wax dispersion, etc. are added, and the surface is coated, Toner base particles having a capsule structure may be used.

Oemulsion polymerization aggregation method The emulsion polymerization aggregation method will be described in more detail below. In the case of producing toner base particles by the emulsion polymerization aggregation method, usually, there are a polymerization step, a mixing step, an aggregation step, an aging step, and a washing / drying step.

  That is, a dispersion liquid containing primary particles of polymer obtained by emulsion polymerization is mixed with a dispersion liquid of each particle such as a colorant, a charge control agent, and wax, and the primary particles in this dispersion liquid are aggregated, preferably A particle aggregate having a volume median diameter (Dv50) of about 3 μm to 12 μm, particularly preferably about 3 μm to 8 μm, and if necessary, resin fine particles or the like are adhered thereto, and then the particle aggregate or resin fine particles adhered. The particle aggregate is fused, and the particles thus obtained are washed and dried to obtain toner base particles. Further, if necessary, external addition is performed to obtain a product toner.

<Polymerization process>
[Polymer primary particles]
The polymer primary particles used in the emulsion polymerization aggregation method preferably have a glass transition temperature (Tg) of 40 ° C to 80 ° C, more preferably 45 ° C to 65 ° C. The volume median diameter (Mv50) is preferably 0.02 μm to 3 μm. The polymer primary particles are obtained by emulsion polymerization of a monomer.

  In emulsion polymerization, a monomer having a Bronsted acidic group (hereinafter sometimes simply referred to as “acidic group”) or a Bronsted basic group (hereinafter simply referred to as “base”) is used as a monomer having a polar group. A monomer having a polar group, that is, a monomer having no polar group, that is, having neither a Bronsted acidic group nor a Bronsted basic group (hereinafter, “other monomers”). And the polymerization is allowed to proceed. At this time, the monomers may be added separately, or a plurality of monomers may be mixed and added in advance. Further, it is possible to change the monomer composition during the monomer addition. The monomer may be added as it is, or may be added as an emulsion prepared by mixing with water or an emulsifier in advance. As the emulsifier, one or two or more combined systems are selected from the above surfactants.

  As the monomer having an acidic group as a polar group used in the present invention, a monomer having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid or cinnamic acid; a sulfonic acid group such as sulfonated styrene Monomer; Monomers having a sulfonamide group such as vinylbenzenesulfonamide and the like.

  Examples of the monomer having a basic group as a polar group include aromatic vinyl compounds having an amino group such as aminostyrene; nitrogen-containing heterocycle-containing monomers such as vinylpyridine and vinylpyrrolidone; dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, etc. And (meth) acrylic acid ester having an amino group.

  Moreover, the monomer which has these polar groups may exist as a salt, respectively with a counter ion.

  The proportion of the monomer having a polar group in the monomers constituting the polymer primary particles is preferably 3% by mass or less in total, based on the total monomers constituting the polymer primary particles. % Or less, more preferably 1% by mass or less, and still more preferably 0.5% by mass or less.

  As the monomer having a polar group, a monomer having an acidic group is preferable, and a monomer having a carboxyl group such as acrylic acid or methacrylic acid is particularly preferable. The ratio of the monomer having a carboxyl group is preferably 3% by mass or less, more preferably 2% by mass or less, and particularly preferably 1% by mass or less, based on the total monomers constituting the polymer primary particles. Preferably, it is 0.5 mass% or less.

  When the proportion of the monomer having a polar group is too large, it becomes easy to absorb moisture, the charging property is deteriorated, the storage stability of the toner (toner solidification property) is deteriorated, or the toner base particles are deteriorated in the aging process. It may be difficult to control the shape.

  Even if the amount of the “monomer having a polar group” that deteriorates various performances of the toner is reduced by increasing the temperature while adding the dispersant in the aging step, the aging step can reduce the amount of “monomer having a polar group”. The particle aggregates do not associate with each other to form particles having a large particle size, and the particle size of the particle aggregate can be stabilized.

  Other comonomers to be copolymerized include styrenes such as styrene, methylstyrene, chlorostyrene, dichlorostyrene, p-tert-butylstyrene, pn-butylstyrene, pn-nonylstyrene; methyl acrylate, Ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, ethyl hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacryl (Meth) acrylic acid esters such as hydroxyethyl acid and ethylhexyl methacrylate; acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N-dipropylacrylamide, N, N-dibu Le acrylamide, and (meth) acrylamides such as acrylamide. Among these, styrene or butyl acrylate is particularly preferable.

  Further, when a crosslinked resin is used for the polymer primary particles, a polyfunctional monomer having radical polymerizability is used as a crosslinking agent shared with the above-mentioned monomers, for example, divinylbenzene, hexanediol diacrylate, ethylene glycol diester. Examples include methacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol acrylate, diallyl phthalate, and the like. A monomer having a reactive group in a pendant group, such as glycidyl methacrylate, methylol acrylamide, or acrolein, can be used.

  Of these, radically polymerizable bifunctional monomers are preferable, and divinylbenzene or hexanediol diacrylate is particularly preferable.

  The blending ratio of such a polyfunctional monomer in the monomer mixture is preferably 0.005% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 0.3% by mass with respect to the whole monomer. Further, it is preferably 5% by mass or less, more preferably 3% by mass or less, and particularly preferably 1% by mass or less.

  These monomers are used alone or as a mixture, and in this case, the glass transition temperature of the polymer is preferably 40 to 80 ° C. If the glass transition temperature exceeds 80 ° C., the fixing temperature may become too high, or the deterioration of OHP transparency may become a problem. On the other hand, if the glass transition temperature of the polymer is less than 40 ° C., toner storage may occur. Stability may deteriorate.

  The polymerization initiator may be added to the polymerization system before, simultaneously with the addition of the monomer, or after the addition, and these addition methods may be combined as necessary.

  In the emulsion polymerization, a known chain transfer agent can be used as necessary. Specific examples of such a chain transfer agent include t-dodecyl mercaptan, 2-mercaptoethanol, diisopropyl xanthogen, four Examples thereof include carbon chloride and trichlorobromomethane. The chain transfer agent may be used alone or in combination of two or more, and is used in an amount of 0 to 5% by mass based on the polymerizable monomer.

  In the emulsion polymerization, the above monomers are mixed with water and polymerized in the presence of a polymerization initiator. The polymerization temperature is usually 50 to 150 ° C, preferably 60 to 120 ° C, more preferably 70 to 100 ° C. .

  The volume median diameter (Mv50) of the polymer primary particles thus obtained is usually in the range of 0.02 μm to 3 μm, preferably 0.03 μm to 2.5 μm, more preferably 0.05 μm to 2 μm, Especially preferably, it is 0.1 micrometer-1 micrometer. The volume median diameter (Mv50) of polymer primary particles and the like is measured and defined by the method described in the examples. When the particle size is smaller than 0.02 μm, it may be difficult to control the aggregation rate. On the other hand, if it is larger than 3 μm, the particle diameter of the toner obtained by aggregation tends to be large, which is not suitable for producing a toner of 3 μm to 8 μm.

[Colorant]
In the emulsion polymerization / aggregation method, a dispersion of polymer primary particles and colorant particles are mixed to obtain a mixed dispersion, which is then aggregated to form particle aggregates. It is preferable to emulsify in water in the presence of an activator) and use it in the form of an emulsion. The volume median diameter (Mv50) of the colorant particles is preferably 0.01 μm to 3 μm. The amount of the colorant used is usually 1 to 25 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the polymer primary particles.

[wax]
In the emulsion polymerization / aggregation method, it is preferable to use a wax that has been dispersed in advance in the presence of an emulsifier (the above-mentioned surfactant) to obtain an emulsified wax fine particle dispersion. The wax is present in the agglomeration step. For this purpose, the wax fine particle dispersion is co-agglomerated with the polymer primary particles and the colorant particles, and the monomer is seed emulsion polymerized in the presence of the wax fine particle dispersion. In some cases, polymer primary particles encapsulating are produced and the colorant particles are aggregated. Among these, in order to uniformly disperse the wax in the toner, it is preferable that the wax fine particle dispersion be present when the above polymer primary particles are formed, that is, when the monomer is polymerized.

  The average particle size of the wax fine particles is preferably 0.01 μm to 3 μm, more preferably 0.1 μm to 2 μm, and particularly preferably 0.3 μm to 1.5 μm. The average particle diameter of the wax fine particles described above is measured using LA-500 manufactured by Horiba. When the average particle size of the wax emulsion is larger than 3 μm, it tends to be difficult to control the particle size during aggregation. Further, when the average particle size of the emulsion is smaller than 0.01 μm, it is difficult to prepare a dispersion.

[Charge control agent]
As a method of incorporating a charge control agent in the emulsion polymerization aggregation method, when obtaining polymer primary particles, the charge control agent is used as a seed simultaneously with the wax, or the charge control agent is dissolved or dispersed in a monomer or wax. After the primary particles of the polymer and the colorant are aggregated together with the primary particles of the charge control agent to form a particle aggregate, or after the primary particles of the polymer and the colorant are aggregated to obtain an appropriate particle size as a toner. The primary particles of the charge control agent can be added to cause aggregation. In this case, the charge control agent is preferably dispersed in water using an emulsifier (the above-mentioned surfactant) and used as an emulsion (primary particles of the charge control agent) having an average particle size of 0.01 to 3 μm. The average particle diameter of the charge control agent fine particles described above was measured using LA-500 manufactured by Horiba, Ltd.

<Mixing process>
In the agglomeration step of the production method of the present invention, the polymer primary particles, the colorant particles, and if necessary, the particles of the blending component such as the charge control agent and the wax are mixed and dispersed simultaneously or sequentially. First, a dispersion of each component, that is, a polymer primary particle dispersion, a colorant particle dispersion, a charge control agent dispersion and a wax fine particle dispersion, if necessary, are mixed and dispersed. It is preferable to obtain a liquid.

  The wax is preferably contained in the toner by using the polymer primary particles encapsulated in the polymer primary particles, that is, the polymer primary particles obtained by emulsion polymerization using the wax as a seed. In this case, the polymer primary particles It is possible to use a wax encapsulated in wax and non-encapsulated wax fine particles in combination, but more preferably, substantially the entire amount of wax is encapsulated in polymer primary particles. is there.

<Aggregation process>
A particle aggregate is prepared by aggregating the mixed dispersion of the above particles in an aggregation step. In this aggregation step, there is a method of performing aggregation by heating. If necessary, an electrolyte may be added to agglomerate.

  When the aggregation is performed by heating, specifically, the aggregation temperature is preferably a temperature range of (Tg-20 ° C.) to Tg (where “Tg” represents the glass transition temperature of the polymer primary particles), The range of (Tg-10 ° C) to (Tg-5 ° C) is particularly preferable. If it is the said temperature range, it can be made to aggregate suitably in a desired toner particle size.

  In addition, in the case of performing aggregation by heating, when the aging process is performed subsequent to the aggregation process, the aggregation process and the aging process are continuously performed, and the boundary may be ambiguous. If there is a step of holding at least 30 minutes in the temperature range of 20 ° C.) to Tg, this is regarded as an aggregation step.

  The aggregation temperature is preferably kept at a predetermined temperature for at least 30 minutes to form toner particles having a desired particle diameter. The temperature may be increased at a constant rate up to a predetermined temperature, or may be increased stepwise. The holding time is preferably in the range of (Tg-20 ° C.) to Tg, preferably from 30 minutes to 8 hours, and more preferably from 1 hour to 4 hours. By doing so, a toner having a small particle size and a sharp particle size distribution can be obtained.

In addition, as an electrolyte in the case of performing aggregation by adding an electrolyte to the mixed dispersion, either an organic salt or an inorganic salt may be used, but a monovalent or divalent or higher polyvalent metal salt is preferably used. . Specifically, NaCl, KCl, LiCl, Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO ₄ , MgCl ₂ , CaCl ₂ , MgSO ₄ , CaSO ₄ , ZnSO ₄ , Al ₂ (SO ₄ ) ₃ , Fe ₂ (SO ₄ ) ₃ , FeSO ₄ , CH ₃ COONa, C ₆ H ₅ SO ₃ Na, and the like.

  One type or several types of electrolyte may be added. The amount of the electrolyte added varies depending on the type of the electrolyte, but usually 0 to 25 parts by weight is used with respect to 100 parts by weight of the solid component of the mixed dispersion. Preferably it is 0-15 weight part, More preferably, it is 0-10 weight part. When the amount of electrolyte added is significantly larger than the above range, it is likely to be agglomerated rapidly and difficult to control, and the obtained particle agglomerates are mixed with coarse powder of 25 μm or more, and the agglomerate shape is irregular and irregular. It may cause problems such as becoming a thing of.

  In addition, when aggregation is performed by adding an electrolyte to the mixed dispersion, the aggregation temperature is preferably in the temperature range of 5 ° C. to Tg.

<Encapsulation process>
Next, in the present invention, it is preferable to form toner base particles by coating (adhering or fixing) resin fine particles on the surface of the particle aggregate after the above-described aggregation step, if necessary. When the charge control agent described above is added after the aggregation step, the resin fine particles may be added after the charge control agent is added to the dispersion containing the particle aggregate.

  The resin fine particles preferably have a volume median diameter (Mv50) of usually 0.02 to 3 μm, preferably 0.05 to 1.5 μm. Examples of the monomer constituting the resin fine particles include the same monomers as those described for the monomer constituting the polymer primary particles.

  The proportion of the monomer having a polar group in the monomer constituting the resin fine particle is preferably 3% by mass or less, and preferably 2% by mass or less in total with respect to the whole monomer constituting the resin fine particle. More preferably, the content is 1% by mass or less, and particularly preferably 0.5% by mass or less. Further, 0% by mass, that is, toner base particles can be prepared by using the present invention even if no monomer having a polar group is contained. Therefore, 0% by mass is charged, storage stability, toner base particles. This is particularly preferable from the viewpoint of controlling the shape.

  As the monomer having a polar group, a monomer having an acidic group is preferable, and a monomer having a carboxyl group such as acrylic acid or methacrylic acid is particularly preferable. The proportion of the monomer having a carboxyl group is preferably 3% by mass or less, more preferably 2% by mass or less, and particularly preferably 1% by mass or less, based on all monomers constituting the resin fine particles. More preferably, it is 0.5 mass% or less. Further, even when 0% by mass, that is, without including the “monomer having a carboxyl group”, toner base particles can be prepared by using the present invention, so that 0% by mass is charged, storage stability, This is particularly preferable from the viewpoint of controlling the shape of the toner base particles.

  When the proportion of the monomer having a polar group is too large, it becomes easy to absorb moisture, the charging property is deteriorated, the storage stability of the toner (toner solidification property) is deteriorated, or the toner base particles are deteriorated in the aging process. It may be difficult to control the shape.

  Even if the amount of the monomer having a polar group that deteriorates various performances of the toner is reduced by increasing the temperature while adding a dispersant in the aging step, the particles in the aging step can be reduced in the aging step. Aggregates do not associate with each other to form particles having a large particle size, and the particle size of the particle aggregate can be stabilized.

  The resin fine particles are preferably used as an emulsion by being dispersed in water or a liquid mainly composed of water with an emulsifier (the above-mentioned surfactant). The fine resin particles used for the outermost layer of the toner may or may not contain wax. However, since the wax is present on the surface of the toner, the wax is more contained in the toner during fixing. It is preferable in that it easily comes out on the surface and easily achieves a releasing effect.

<Aging process>
In the emulsion polymerization aggregation method, in order to increase the stability of the particle aggregate (toner base particles) obtained in the aggregation process, from the temperature of the aggregation process (when the temperature is changed, the final temperature of the aggregation process), “ An aging step for causing fusion between the aggregated particles is added while the temperature is raised to a temperature in the range of (Tg + 10 ° C.) to (Tg + 80 ° C.) (where Tg is the glass transition temperature of the polymer primary particles). Hereinafter, the temperature range from “the lowest temperature at which fusion between particles occurs to“ temperature in the range of (Tg + 10 ° C.) to (Tg + 80 ° C.) ”is abbreviated as“ temperature range of aging step ”. The temperature increase rate in the aging step is preferably 10 ° C./min or less, more preferably 5 ° C./min or less, particularly preferably 3 ° C./min or less, from the viewpoint of controlling the particle size of the particle aggregate. Further, the temperature increase may be stopped in the middle, and the temperature increase may be started again after being held for a certain time.

  However, if the temperature is raised as it is, the particle size of the particle aggregate further grows and exceeds the target particle size. Before raising the temperature to the temperature range of the aging step, a dispersing agent such as an emulsifier and a pH adjuster is usually added, and an operation for suppressing the growth of particle aggregates in the aging step is added.

  As such a dispersant, an emulsifier is preferable. As the emulsifier, the same surfactants as those described in the production of the polymer primary particles are preferable. Among these, it is preferable to use the same surfactant as that used when producing the polymer primary particles. The emulsifier is used in one or more combined systems.

  The pH adjusting agent is not particularly limited as long as it can be dissolved in water to adjust the pH, but is preferably one that can adjust a pH of less than 5 to a range of 5 to 7. Specifically, for example, sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, sodium acetate, aqueous ammonia, amine compounds, or the like, or those obtained by changing these sodium salts to alkali metal salts such as potassium salts, etc. .

  In the present invention, the method for adding the dispersant is not performed at once, and the temperature is increased while adding the dispersant without adding the dispersant and then increasing the temperature. If added all at once before raising the temperature to the temperature range of the aging process, a large amount of dispersant may be required. In some cases, even if a large amount of dispersant is used, particle aggregation is controlled in the aging process. I can't do it and it grows big.

  When a large amount of dispersant is added, it may take a long time to control the shape of the toner base particles in the aging step. In addition, since it is necessary to remove a large amount of dispersant, a large amount of washing water is required in the toner mother particle washing process, and the wastewater increases the burden on the environment, and the wastewater treatment costs high. There is a case.

  In addition, when the dispersant is added all at once before raising the temperature to the temperature range of the aging step, in the case of a particle aggregate having a low or no polar group content and low stability, a large amount of the dispersant may be used. Even if it is added to the particles, the particle aggregates may grow greatly when the temperature is raised in the aging step. Further, the volume median diameter (Dv50) cannot be controlled, and a large amount of coarse particles is generated, which may result in a toner that is inappropriate for high image quality and high speed.

  There is no particular limitation on the method of raising the temperature while adding the dispersant, but there are a method of raising the temperature while continuously adding the dispersant, a method of raising the temperature while adding the dispersant in stages, and the like. preferable. While adding the dispersant, the temperature is raised within the temperature range of the aging step. Thus, even when the temperature is increased while adding the dispersant, adding a part of the dispersant before the temperature is increased to the temperature range of the aging step may greatly increase the particle aggregate. This is preferable in order to prevent generation of coarse particles.

  In the case of increasing the temperature while adding the dispersant in stages, the temperature is divided into at least two stages, preferably four stages or more, particularly preferably six stages or more. Moreover, it is more preferable to add continuously. Further, it is preferable that the addition temperature is divided almost uniformly within the temperature range of the aging step. Even in this case, it is preferable to add a part of the dispersant before the temperature is raised to the temperature range of the aging step for the same reason as the continuous addition.

  In addition, when the temperature is increased while adding the dispersant in stages, the temperature is increased to 1 stage / 10 ° C. or higher (ie, “divided dispersant” is added at least once during the temperature increase of 10 ° C. It is preferable to perform the second stage / 10 ° C. or higher, more preferably the third stage / 10 ° C. or higher, and still more preferably continuously.

  When the dispersant is added stepwise, the same amount may be added each time, or a different amount may be added each time. When the dispersant is added continuously, the addition rate of the dispersant may be uniform rate addition or rate fluctuation addition. The addition amount and the addition speed of the dispersant are preferably determined depending on the stability of the particle aggregate. When the dispersant is a pH adjuster, it is preferable to add continuously or stepwise so that the pH during the ripening step is always within the preferred range.

  As described above, the time required for the temperature increase in the temperature range of the aging step is not particularly limited, but is preferably 10 minutes to 4 hours, more preferably 20 minutes to 2 hours, and particularly preferably 30 minutes to 1 hour. Therefore, it is preferable to add the dispersant once every 20 minutes or less, more preferably once every 10 minutes or less, particularly preferably once every 5 minutes or less, and continuously. Further preferred.

  The aging step may be performed only by the above-mentioned operation, but after that, it is preferable to hold for a certain time at a temperature in the range of (Tg + 10 ° C.) to (Tg + 80 ° C.), that is, the final temperature or the maximum temperature of the aging step. The fixed time is not particularly limited, but is preferably 30 minutes to 24 hours, particularly preferably 1 hour to 10 hours. By applying such an operation, the shape of the toner particles can be made nearly spherical, and the shape can be controlled.

  The dispersant may be added as it is, but it is preferably diluted and added as a solution. Usually, 2% to 40% by weight, preferably 5% to 30% by weight, particularly preferably 10% to 20% by weight of solution is used.

  The particle aggregate before the aging step is considered to be an aggregate due to electrostatic or other physical aggregation of the primary particles, but after the aging step, the polymer primary particles constituting the particle aggregate are fused to each other. And is preferably substantially spherical. In addition, according to such a toner production method, various shapes can be selected depending on the purpose, such as a cocoon type in which primary particles are aggregated, a potato type in which fusion has progressed to the middle, and a spherical shape in which fusion has further progressed. Toner can be produced.

<Washing and drying process>
The particle aggregate obtained by going through each of the above steps is subjected to solid-liquid separation according to a known method, the particle aggregate is recovered, and then this is washed as necessary and dried. Toner particles can be obtained.

Suspension polymerization aggregation method When producing toner base particles by suspension polymerization aggregation method, it usually has a polymerization process, a mixing process, an aggregation process, an aging process, and a washing / drying process.

  That is, a dispersion containing primary particles of polymer obtained by suspension polymerization is mixed with a dispersion of each particle such as a colorant, a charge control agent, and wax, and the primary particles in the dispersion are aggregated, Is a particle aggregate having a volume median diameter (Dv50) of about 3 μm to 12 μm, particularly preferably about 3 μm to 8 μm, and if necessary, resin fine particles or the like are attached thereto, and the particle aggregates or resin fine particles are attached. The particle aggregates are fused, and the toner particles thus obtained are washed and dried to obtain product toner particles.

  In the toner of the present invention, a known external additive may be added to the toner base particles produced as described above in order to control fluidity and developability. As the external additive, various inorganic oxide particles such as silica, alumina, and titania (hydrophobized if necessary), vinyl polymer particles, and the like can be used. The addition amount of the external additive is preferably in the range of 0.05 to 5 parts by weight with respect to 100 parts by weight of the toner base particles.

  The toner used in the present invention can be applied to a two-component developer, a magnetic one-component developer such as a magnetite-containing toner, a non-magnetic one-component developer, and the like.

  When used as a two-component developer, the carrier that is mixed with the toner to form the developer may be a known magnetic substance such as an iron powder, ferrite, or magnetite carrier, or a resin coating on the surface thereof. Or a magnetic resin carrier can be used. As the carrier coating resin, generally known styrene resins, acrylic resins, styrene acrylic copolymer resins, silicone resins, modified silicone resins, fluorine resins, and the like can be used, but are not limited thereto. It is not a thing. The average particle diameter of the carrier is not particularly limited, but preferably has an average particle diameter of 10 μm to 200 μm. These carriers are preferably used in an amount of 5 to 100 parts by weight based on 1 part by weight of the toner.

  The toner production method of the present invention is preferably applied to a toner having a volume median diameter (Dv50) of 3 μm to 12 μm. The volume median diameter (Dv50) is more preferably 3 μm to 10 μm, particularly preferably 3 μm to 8 μm, and still more preferably 4 μm to 7 μm. When the volume median diameter (Dv50) is too large, it is not suitable for high-resolution image formation, and the effect of applying the production method of the present invention may be diminished, and when it is too small, handling as a powder becomes difficult. There is. The toner obtained by the production method of the present invention has a sharp particle size distribution and is suitable as a toner for achieving high image quality and high speed. The volume median diameter (Dv50) is defined as a value measured by the method described in the Examples and measured as such.

  The toner production method of the present invention is preferably applied to the case where the relationship between the volume median diameter (Dv50) and the number median diameter (Dn50) is 1.0 ≦ Dv50 / Dn50 ≦ 1.3. The value of “Dv50 / Dn50” is preferably 1.25 or less, and particularly preferably 1.20 or less. Moreover, although the lower limit of Dv50 / Dn50 is 1, this means that the particle diameter of all the particles is equal, and since it is difficult to manufacture, 1.03 or more is preferable, and 1.05 or more is particularly preferable. preferable.

  The toner preferably has few fine particles (fine powder). When the number of fine particles is small, the fluidity of the toner is improved, and the colorant, the charge control agent, and the like are uniformly distributed and the chargeability tends to be uniform. In the present invention, it is preferable to use for the production of toner in which the measured value (number) of particles of 0.60 μm to 2.12 μm by a flow particle image analyzer is 15% or less of the total number of particles. This means that the number of fine particles is less than a certain amount, but the number of particles of 0.60 μm to 2.12 μm is more preferably 10% or less, and particularly preferably 5% or less. Further, there is no particular lower limit to the number of particles of 0.60 μm to 2.12 μm, and it is most preferable that there is no particle at all. is there.

  The average circularity of the toner is preferably 0.9 to 1. The average circularity is measured by the method described in the examples, and is defined as a value measured as such.

  In order to achieve a suitable particle size distribution of the toner of the present invention, an emulsion polymerization aggregation method is particularly preferable. A toner having a sharp particle size distribution is advantageous for forming a high-definition image because the colorant, the charge control agent, and the like are more uniformly distributed and the chargeability is uniform.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, “parts” means “parts by weight”.

<Measurement method of volume median diameter (Mv50)>
The volume median diameter (Mv50) of polymer primary particles of less than 3 μm and wax particles in a wax dispersion is “Microtrac UPA (ultra particle analyzer)” (hereinafter abbreviated as “UPA”) manufactured by Nikkiso Co., Ltd. Used and defined as a value measured in the usual way according to the instructions of the apparatus.

<Measurement method of volume median diameter (Dv50)>
The volume median diameter (Dv50) of the toner of 3 μm or more is 0 for the ISOTON (manufactured by ISOTON Coulter Scientific Japan Co., Ltd.) using a multisizer type II manufactured by Beckman Coulter and having an aperture diameter of 100 μm. This is defined as the volume-based volume median diameter (Dv50) obtained from the volume distribution of the toner obtained by measurement using the third to sixteenth channels for the toner dispersed at 0.03%.

<Method for measuring the number median diameter (Dn50)>
The median diameter (Dn50) of the toner is Multisizer II type manufactured by Beckman Coulter, and the aperture diameter is 100 μm, and 0.03% in Isoton (ISOTON Coulter Scientific Japan). Is defined as a number-based number median diameter (Dn50) obtained from a toner number distribution obtained by measurement using the third to sixteenth channels.

<Measuring method of toner amount of 12 μm or more>
The volume median diameter (Dv50) is measured in the same manner as described above, and the volume fraction of the toner of 12 μm or more is calculated from the volume particle size measurement result of the toner using the analysis software attached to the Multisizer II type. This was defined as “a toner amount of 12 μm or more”.

<Average circularity measurement>
The average circularity is determined by dispersing the dispersoid in a dispersion medium (Cell Sheath: Sysmex) at 5720-7140 / μL, and using a flow particle analyzer (FPIA2000: Sysmex) to analyze the amount of HPF. It is measured in the HPF mode under the condition of 0.35 μL and HPF detection amount 2000 to 2500, and is defined as a value obtained from the following formula.
Circularity = circumference of a circle with the same area as the projected particle area / circumference of the projected particle image

<Electrical conductivity measurement>
The electrical conductivity was measured using a conductivity meter (CyberScanCON100 manufactured by ASONE Corporation).

<Thermal characteristics>
From the endothermic curve when the temperature was increased from 10 ° C. to 110 ° C. at a rate of 10 ° C./min using the Perkin Elmer thermal analyzer DSC7, the melting point, heat of fusion, The half-width of the melting peak was measured, and then the crystallization temperature and the half-width of the crystallization peak were measured from an exothermic curve when the temperature was lowered from 110 ° C. to 10 ° C. at a rate of 10 ° C./min.

<Weight average molecular weight (Mw)>
The THF-soluble component of the polymer primary particle dispersion was measured by gel permeation chromatography (GPC) under the following conditions.
Apparatus: GPC apparatus HLC-8020 manufactured by Tosoh Corporation, column: PL-gel Mixed-B 10μ manufactured by Polymer Laboratory, solvent: THF, sample concentration: 0.1% by mass, calibration curve: standard polystyrene

--- Preparation of dispersion ---
<Preparation of wax / long-chain polymerizable monomer dispersion A1>
Paraffin wax (Nippon Seiwa Co., Ltd. HNP-9, surface tension 23.5 mN / m, thermal characteristics: melting point 82 ° C., heat of fusion 220 J / g, melting peak half width 8.2 ° C., crystallization temperature 66 ° C., crystallization Peak half-value width 13.0 ° C. 27 parts (270 g), stearyl acrylate (Tokyo Kasei Co., Ltd.) 2.8 parts, 20% sodium dodecylbenzenesulfonate aqueous solution (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S20A, hereinafter, “20 1.9 parts) (abbreviated as “% DBS aqueous solution”) and 68.3 parts of demineralized water were heated to 90 ° C. and stirred for 10 minutes using a homomixer (Mark IIf model, manufactured by Tokushu Kika Kogyo Co., Ltd.). Next, under heating at 90 ° C., circulation emulsification was started under a pressure condition of 25 MPa using a homogenizer (manufactured by Gorin Co., Ltd., LAB 60-10TBS type), the particle diameter was measured with UPA, and the volume median diameter (Mv50) was 250 nm. To obtain a wax / long-chain polymerizable monomer dispersion A1 (emulsion solid content concentration = 30.2%).

<Preparation of silicone wax dispersion B1>
Alkyl-modified silicone wax (thermal characteristics: melting point 77 ° C., heat of fusion 97 J / g, melting peak half-width 10.9 ° C., crystallization temperature 61 ° C., crystallization peak half-width 17.0 ° C.) 27 parts, 20% DBS aqueous solution 1.9 parts and 71.1 parts of demineralized water were heated to 90 ° C. and stirred for 10 minutes with a homomixer (Mark IIf model, manufactured by Tokushu Kaika Co., Ltd.). Subsequently, this dispersion was heated to 99 ° C., and circulation emulsification was started under a pressure of 45 MPa using a homogenizer (manufactured by Gorin Co., Ltd., LAB 60-10TBS type). The volume median diameter (Mv50) was measured while measuring with UPA. Was dispersed to 240 nm to prepare a silicone wax dispersion B1 (emulsion solid content concentration = 27.4%).

<Preparation of polymer primary particle dispersion C1>
35. Wax / long-chain polymerizable monomer dispersion A1 35. In a reactor (internal volume 40 m ³ ) equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and a raw material / auxiliary charging device. 6 parts and 266 parts of demineralized water were charged, and the temperature was raised to 90 ° C. under a nitrogen stream while stirring.

  Then, the mixture of the following monomers and emulsifier aqueous solution was added over 5 hours, continuing stirring. The time at which dropping of the mixture of the monomers and the aqueous emulsifier solution was started as the polymerization start, and the following “initiator aqueous solution 1” was added over 4.5 hours from 30 minutes after the start of the polymerization. “Initiator aqueous solution 2” was added over 2 hours. Thereafter, the inner temperature was maintained at 90 ° C. for 1 hour under stirring.

[Monomers]
Styrene 76.8 parts Butyl acrylate 23.2 parts Acrylic acid 1.5 parts Hexanediol diacrylate 0.7 parts Bromotrichloromethane 1.0 part [Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part demineralized water 67.1 parts

[Initiator aqueous solution 1]
8% aqueous hydrogen peroxide solution 15.5 parts 8% L-(+) ascorbic acid aqueous solution 15.5 parts [initiator aqueous solution 2]
8% L-(+) ascorbic acid aqueous solution 14.2 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion C1. The volume median diameter (Mv50) of the polymer primary particles measured using UPA was 210 nm, and the weight average molecular weight (Mw) was 78,300.

<Preparation of resin fine particle dispersion D1>
In a reactor (internal volume 5 L) equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and each raw material / auxiliary charging device, 23.0 parts (103.6 g) of the above silicone wax dispersion B1; Charge 0.5 parts of 20% DBS aqueous solution and 318 parts of demineralized water, raise the temperature to 90 ° C. under a nitrogen stream, and stir while stirring, 3.2 parts of 8% aqueous hydrogen peroxide solution, 8% L-(+) ascorbine. 3.2 parts of an acid aqueous solution was added all at once.

  Five minutes after that, while the stirring was continued, dropping of a mixture of the following monomers and an aqueous emulsifier solution was started and added over 5 hours. Simultaneously with the start of the dropwise addition of the mixture of the monomers and the aqueous emulsifier solution, the following "initiator aqueous solution 3" was also started to be added over 6 hours. While stirring, the internal temperature was maintained at 90 ° C. for 1 hour.

[Monomers]
Styrene 79.0 parts 2-ethylhexyl acrylate 21.0 parts Bromotrichloromethane 0.5 parts [Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part Demineralized water 65.7 parts

[Initiator aqueous solution 3]
8% aqueous hydrogen peroxide solution 18.8 parts 8% L-(+) ascorbic acid aqueous solution 18.8 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain milky white resin fine particle dispersion D1. The volume median diameter (Mv50) of the polymer primary particles measured using UPA was 222 nm, and the weight average molecular weight (Mw) was 49,800.

<Preparation of resin fine particle dispersion D2>
In a reactor (internal volume 5 L) equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and each raw material / auxiliary charging device, 23.2 parts (104.3 g) of silicone wax dispersion B1 Charge 0.5 parts of 20% DBS aqueous solution and 321 parts of demineralized water, raise the temperature to 90 ° C. under a nitrogen stream, and while stirring, 3.2 parts of 8% aqueous hydrogen peroxide solution, 8% L-(+) ascorbine 3.2 parts of an acid aqueous solution was added all at once.

  Five minutes after that, while the stirring was continued, dropping of a mixture of the following monomers and an aqueous emulsifier solution was started and added over 5 hours. Simultaneously with the start of the dropwise addition of the mixture of the monomers and the aqueous emulsifier solution, the following "initiator aqueous solution 3" was also started to be added over 6 hours. While stirring, the internal temperature was maintained at 90 ° C. for 1 hour.

[Monomers]
Styrene 83.5 parts Butyl acrylate 16.5 parts Acrylic acid 0.2 parts Bromotrichloromethane 1.0 part [Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part Demineralized water 65.8 parts

[Initiator aqueous solution 3]
8% aqueous hydrogen peroxide solution 18.8 parts 8% L-(+) ascorbic acid aqueous solution 18.8 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain milky white resin fine particle dispersion D2. The volume median diameter (Mv50) of the polymer primary particles measured using UPA was 212 nm, and the weight average molecular weight (Mw) was 56,200.

[1] Examples using polymer primary particle dispersion C1 and resin fine particle dispersion D1 and Comparative Example 1
<Manufacture of toner mother particles E1>
[Aggregation process]
In a mixer (internal volume 2 L) equipped with a stirrer (double helical blade), heating / cooling device, concentrating device, and each raw material / auxiliary charging device, 90 parts of polymer primary particle dispersion C1 (solid content) (1070 g) The inner temperature was adjusted to 8 ° C., and 0.1 part (solid content) of a 20% DBS aqueous solution was added and mixed uniformly. Further, a 5% aqueous solution of ferrous sulfate (0.12 parts as FeSO ₄ .7H ₂ O) was added over 5 minutes. Subsequently, 4.4 parts (solid content) of cyan pigment dispersion (EP750 manufactured by Dainichi Seika Co., Ltd.) was added over 5 minutes and mixed uniformly, and then 21.7 parts of demineralized water was added dropwise. During this time, the internal temperature was kept at 8 ° C.

  Thereafter, the temperature was raised to 52 ° C. over 50 minutes, and further raised to 58 ° C. over 80 minutes. Here, it was 6.8 micrometers when the volume median diameter (Dv50) was measured using the multisizer.

[Encapsulation process]
Then, after cooling internal temperature to 54 degreeC, 10 parts (solid content) of resin fine particle dispersion D1 was added over 10 minutes, and it hold | maintained at 54 degreeC for 60 minutes.

[Aging process]
Subsequently, the temperature was increased from 54 ° C. to 85 ° C. over 40 minutes while keeping the temperature increase rate constant. Dropping was started simultaneously with the temperature increase from 54 ° C. to 85 ° C., and 6 parts of 20% DBS aqueous solution (solid content) was added over 40 minutes while keeping the addition rate constant in parallel with the temperature increase. Thereafter, the temperature was raised from 85 ° C. to 95 ° C. over 10 minutes without adding a 20% DBS aqueous solution, and the state was maintained as it was. The average circularity was measured with a flow particle analyzer. When the average circularity reached 0.97, the slurry was cooled to 30 ° C. over 30 minutes to obtain a slurry.

  The volume median diameter (Dv50) after cooling was 7.0 μm, and the average circularity measured by a flow particle analyzer was 0.970.

[Washing and drying process]
The slurry was extracted and subjected to suction filtration with an aspirator using 5 types C (No. 5C manufactured by Toyo Roshi Kaisha, Ltd.) filter paper. The cake remaining on the filter paper is transferred to a stainless steel container having an internal volume of 10 L equipped with a stirrer (propeller blade), added with 8 kg of ion-exchanged water having an electric conductivity of 1 μS / cm, and stirred uniformly at 50 rpm to be dispersed uniformly. Thereafter, the mixture was left stirring for 30 minutes.

  After that, it was again filtered by suction using 5 C filter paper with an aspirator, and the solid matter remaining on the filter paper was again equipped with a stirrer (propeller blade) and charged with 8 kg of ion-exchanged water having an electric conductivity of 1 μS / cm. The sample was transferred to a stainless steel container having an internal volume of 10 L, and uniformly dispersed by stirring at 50 rpm, and stirred for 30 minutes. This process was repeated until the electrical conductivity of the filtrate was 2 μS / cm.

  The obtained cake was spread on a stainless steel bat so as to have a height of 20 mm, and dried in a blow dryer set at 40 ° C. for 48 hours to obtain toner mother particles E1.

<Manufacture of toner F1>
100 parts of toner mother particles E1 are put into Kyoritsu Riko Co., Ltd. sample mill KR-3, and then 1.5 parts of silica fine particles having a volume average primary particle size of 0.015 μm hydrophobized with silicone oil are added. The toner F1 was obtained by adding, stirring and mixing, and sieving.

  The volume median diameter (Dv50), number median diameter (Dn50), and Dv50 / Dn50 of the obtained toner F1 were determined by the above methods. The results are shown in Table 2.

Example 2
<Manufacture of toner mother particles E2>
In Example 1, instead of heating from 54 ° C. to 85 ° C. while adding 6 parts of 20% DBS aqueous solution (solid content) over 40 minutes, 6 parts of 20% DBS aqueous solution (solid content) Example 1 except that during the temperature increase up to 85 ° C., the internal temperature was 54 ° C., 60 ° C., 65 ° C., 70 ° C., 75 ° C., 80 ° C. In the same manner, toner mother particles E2 were obtained.

  The volume median diameter (Dv50) after cooling was 7.1 μm, and the average circularity measured by a flow particle analyzer was 0.970.

<Manufacture of toner F2>
Toner F2 was obtained in the same manner as in Example 1 except that toner base particle E2 was used instead of toner base particle E1. The volume median diameter (Dv50), number median diameter (Dn50), and Dv50 / Dn50 of the obtained toner F2 were determined by the above methods. The results are shown in Table 2.

Comparative Example 1
<Manufacture of toner mother particles E3>
In Example 1, instead of heating from 54 ° C. to 85 ° C. while adding 6 parts of 20% DBS aqueous solution (solid content) over 40 minutes, 6 parts of 20% DBS aqueous solution (solid content) was started to be heated. Toner mother particles E3 were obtained in the same manner as in Example 1 except that the addition was performed all within 5 minutes.

  The volume median diameter (Dv50) after cooling was 7.9 μm, and the average circularity measured by a flow particle analyzer was 0.973.

<Manufacture of toner F3>
Toner F3 was obtained in the same manner as in Example 1 except that toner base particle E2 was used instead of toner base particle E1. The volume median diameter (Dv50), number median diameter (Dn50), and Dv50 / Dn50 of the obtained toner F3 were determined by the above methods. The results are shown in Table 2.

Comparative Example 2
<Manufacture of toner mother particle E4>
Toner base particles E4 were obtained in the same manner as in Comparative Example 1 except that the amount of 20% DBS aqueous solution used was changed from 6 parts (solid content) to 12 parts (solid content).

  The volume median diameter (Dv50) after cooling was 7.5 μm, and the average circularity measured by a flow particle analyzer was 0.970.

<Manufacture of toner F4>
Toner F4 was obtained in the same manner as in Example 1 except that toner base particle E4 was used instead of toner base particle E1. The volume median diameter (Dv50), number median diameter (Dn50), and Dv50 / Dn50 of the obtained toner F4 were determined by the above methods. The results are shown in Table 2.

[2] Examples using polymer primary particle dispersion C1 and resin fine particle dispersion D2 and Comparative Example 3
<Manufacture of toner mother particles E5>
In Example 1, after the volume median diameter (Dv50) reached 6.8 μm in the aggregation step, the resin fine particle dispersion D2 was used instead of the resin fine particle dispersion D1 in the encapsulation step, and in the aging step Toner mother particles E5 were obtained in the same manner as in Example 1 except that 6 parts of 20% DBS aqueous solution (solid content) was used instead of 3 parts of 20% DBS aqueous solution (solid content).

  The volume median diameter (Dv50) after cooling was 7.1 μm, and the average circularity measured by a flow type particle analyzer was 0.977.

<Manufacture of toner F5>
Toner F5 was obtained in the same manner as in Example 1 except that E5 was used instead of toner base particle E1. The volume median diameter (Dv50), number median diameter (Dn50), and Dv50 / Dn50 of the obtained toner F5 were determined by the above methods. The results are shown in Table 2.

Comparative Example 3
<Production of toner base particles E6>
In Example 3, while adding 3 parts of 20% DBS aqueous solution (solid content) over 40 minutes, instead of increasing the temperature from 54 ° C. to 85 ° C., 6 parts of 20% DBS aqueous solution (solid content) started to rise. Toner mother particles E6 were obtained in the same manner as in Example 3 except that the addition was collectively performed within 5 minutes.

  The volume median diameter (Dv50) after cooling was 7.2 μm, and the average circularity measured by a flow particle analyzer was 0.973.

<Manufacture of toner F6>
Toner F6 was obtained in the same manner as in Example 1 except that toner base particle E6 was used instead of toner base particle E1. The volume median diameter (Dv50), number median diameter (Dn50) and Dv50 / Dn50 of the obtained toner F6 were determined by the above methods. The results are shown in Table 2.

Comparative Example 4
<Manufacture of toner mother particle E7>
Toner mother particles E7 were obtained in the same manner as in Example 3 except that the 20% DBS aqueous solution was changed from 6 parts (solid content) to 3 parts.

  The volume median diameter (Dv50) after cooling was 8.3 μm, and the average circularity measured by a flow particle analyzer was 0.970.

<Manufacture of toner F7>
Toner F7 was obtained in the same manner as in Example 1 except that toner base particle E7 was used instead of toner base particle E1. The volume median diameter (Dv50), number median diameter (Dn50), and Dv50 / Dn50 of the obtained toner F7 were determined by the above methods. The results are shown in Table 2.

<Fixing test>
When recording paper carrying an unfixed toner image is prepared, the surface temperature of the heating roller is changed from 100 ° C. to 210 ° C. in increments of 5 ° C., conveyed to the fixing nip, and discharged at a speed of 120 mm / sec. The fixing state of was observed. The temperature range where the toner on the recording paper after fixing is sufficiently adhered to the recording paper without fixing toner on the heating roller during fixing is the “fixing temperature range”, and the lower limit is the “minimum fixing temperature” It was. The heating roller of the fixing machine has a release layer made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) and was evaluated without application of silicone oil.

The image quality was judged in the following three stages.
○: Uniform image, no streaks △: Some image unevenness ×: Many image unevenness, streaks may occur

  From Examples 1 to 3, even if the proportion of the monomer having a polar group (acrylic acid in Examples 1 to 3) is as small as 1.5 parts in the monomer units constituting the polymer primary particles, the volume median diameter It was possible to age by controlling so that (Dv50) would not become too large.

  When Examples 1 and 2 that do not contain a monomer having a polar group are compared with Comparative Examples 1 and 2 that do not contain a monomer in the monomer unit constituting the resin fine particles used in the encapsulation process, the dispersant (DBS) is increased. In Examples 1 and 2, which were continuously added while heating or added in 6 steps, a toner having a particle size distribution of 12 μm or more and less than 1% and having a good particle size distribution was obtained. In Comparative Example 1 in which the toner was added all at once, the toner amount of 12 μm or more was 18%, which was inferior in particle size distribution, and both the image quality and the fixability were inferior.

  In Comparative Example 2, 12 parts of the dispersant (DBS) was used. However, the toner amount of 12 μm or more was only 5% and the particle size distribution was inferior. Furthermore, since a large amount of dispersant (DBS) was used, a large amount of water had to be used for cleaning, which was disadvantageous in terms of cleaning cost and waste liquid cost.

  Comparative Example 3 including 0.2 part of Example 3 containing 0.2 part of a monomer having a polar group (in this case, acrylic acid) in the monomer unit constituting the resin fine particles used in the encapsulation step, In comparison with Example 4, in Example 3 in which a dispersant (DBS) was continuously added while raising the temperature, the toner amount of 12 μm or more was less than 1%, and a good particle size distribution was obtained, and the image quality was also good. However, in Comparative Example 4 in which the dispersant (DBS) was added all at once, the toner amount of 12 μm or more was 50% or more, and the aggregated particles were associated with each other in the ripening process. It was inferior to.

  In the case where 0.2 part of acrylic acid is contained in the monomer unit constituting the resin fine particles, even if a dispersant (DBS) is added all at once, if 6 parts are used, the particle size distribution is temporarily increased. Although it can be improved (Comparative Example 3), in order to remove the dispersing agent (DBS), as much as 48 L of washing water must be used, which is extremely disadvantageous in terms of washing cost and waste liquid cost.

  In the ripening step, toner base particles having a sharp particle size distribution are stably obtained by “heating the temperature while adding a dispersant” by continuous addition, stepwise addition, etc. Excellent image quality and low-temperature fixability. In addition, the amount of dispersant such as DBS can be reduced. Finally, the amount of emulsifier and wastewater discharged in the toner mother particle washing process can be reduced, the burden on the environment can be reduced, and the cost is extremely low. It was advantageous.

  Since the electrostatic image developing toner of the present invention has the above-described effects, it is useful as an electrostatic image developing toner that can be used in printers, printing machines, copiers and the like that require high-quality images. Therefore, it is widely used in all fields where electrophotographic methods are used.

Claims (16)

  Agglomeration step of aggregating particles while stirring a dispersion containing at least polymer primary particles and colorant particles to obtain particle agglomerates; and the particle agglomerates at a temperature higher than the glass transition temperature of the polymer primary particles. A method for producing a toner for developing an electrostatic charge image, comprising a ripening step for fusing, wherein the temperature is raised while adding a dispersant in the ripening step.   The method for producing a toner for developing an electrostatic charge image according to claim 1, further comprising an encapsulation step of adding resin fine particles to adhere to the surface of the particle aggregate after the aggregation step and before the aging step.   3. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein a proportion of the monomer having a polar group in the monomer constituting the polymer primary particle is 3% by mass or less.   4. The method for producing a toner for developing an electrostatic charge image according to claim 2, wherein the proportion of the monomer having a polar group in the monomer unit constituting the resin fine particle is 3% by mass or less.   The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 to 4, wherein when the temperature is increased while adding the dispersant, the dispersant is continuously added. .   The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 to 5, wherein the polymer primary particles are obtained by an emulsion polymerization method.   The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 to 6, wherein the primary particle of the polymer has a glass transition temperature of 40 ° C to 80 ° C.   The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 to 7, wherein a volume median diameter (Mv50) of the polymer primary particles is 0.02 µm to 3 µm.   The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 to 8, wherein the polymer primary particles contain a wax.   The method for producing a toner for developing an electrostatic charge image according to claim 9, wherein the volume median diameter (Mv50) of the wax contained in the polymer primary particles is 0.01 μm to 3 μm.   The method for producing a toner for developing an electrostatic charge image according to claim 9 or 10, wherein the wax has a melting point of 30C to 100C.   The static polymer according to any one of claims 9 to 11, wherein the polymer primary particles contain 1 to 40 parts by weight of the wax with respect to 100 parts by weight of the binder resin. A method for producing a toner for developing a charge image.   13. The electrostatic charge image developing device according to claim 1, wherein a ratio of the polyfunctional monomer in the monomer constituting the polymer primary particle is 0.005% by mass to 5% by mass. Toner manufacturing method.   The method for producing a toner for developing an electrostatic charge image according to any one of claims 2 to 13, wherein the resin fine particles contain a wax.   The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 to 14, wherein the obtained electrostatic charge image developing toner has a volume median diameter (Dv50) of 3 to 12 µm.   16. The ratio “Dv50 / Dn50” between the volume median diameter (Dv50) and the number median diameter (Dn50) of the obtained toner for developing an electrostatic charge image is 1 to 1.3. A method for producing a toner for developing an electrostatic image according to claim 1.