JP4697540B2 - 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 that can be suitably used in a printer having an electrophotographic developing method. More specifically, the present invention relates to a method for producing a toner for developing an electrostatic image, which has high productivity and has a narrow particle size distribution so that a high-quality image can be obtained.

  In general, in the formation of a visible image by an electrophotographic method, first, an electrostatic latent image is formed on a photosensitive drum, then developed with toner, and then transferred to transfer paper, a transparent film, etc., and heat, pressure, etc. It is made by fixing by. As a toner for developing an electrostatic image at that time, conventionally, a binder resin and a colorant are mixed with a charge control agent, a release agent, a magnetic material, and the like as necessary, and then melt-kneaded with an extruder or the like. Subsequently, after kneading and classifying the kneaded product, a so-called melt kneading and pulverizing method in which fine particles such as silica are adhered to the surface for the purpose of imparting fluidity and the like has been used.

  In recent years, image quality should be improved as a performance of copying machines, printers, and the like. To achieve this, toner particles with a narrow particle size distribution are required. Since it is difficult to control the diameter and a large amount of coarse powder and fine powder that deviate from the desired particle diameter are by-produced, it has been a problem that it is necessary to classify them in the classification step.

  As a method for improving the above problems in the melt-kneading and pulverizing method, a suspension polymerization method in which a polymerizable monomer, a polymerization initiator, a colorant and the like are suspended and dispersed in an aqueous medium and then polymerized to produce toner particles. Alternatively, the polymer primary particle emulsion obtained by emulsifying a polymerizable monomer in an aqueous medium containing a polymerization initiator and an emulsifier and polymerizing this is added with a colorant and, if necessary, a charge control agent. There has been proposed an emulsion polymerization aggregation method or the like in which the polymer primary particles are added to agglomerate, and the agglomerated particles are further fused to produce toner particles. These polymerization methods are easy to control the particle size of the toner particles, so that it is possible to obtain a toner having a small particle size and a narrow particle size distribution, and excellent image quality. Thus, the low-temperature fixability can be improved.

  On the other hand, in the case of the melt kneading and pulverizing method, it is possible to efficiently produce toner by continuously supplying the components. Further, even when switching to the production of different types of toner, the self-cleaning effect of the kneading apparatus can be reduced. Because it is high, it was possible to produce continuously by changing the components. On the other hand, when the toner is produced by the polymerization method, the resin polymerization step in the suspension polymerization method or the emulsion polymerization aggregation method can be continued, but in particular the granulation step in the emulsion polymerization aggregation method, that is, the aggregation As for the process and the fusion process, for example, as shown in Patent Document 1, a batch-type manufacturing method has been conventionally employed.

In general, it is well known that conversion from a batch production method to a continuous production method improves production efficiency and yields a homogeneous product if the production conditions are stable. The reason why the granulation step in the method was not carried out continuously was that it was thought that problems such as difficulty in controlling the particle size and controlling the particle size distribution would occur when trying to carry out this. As described above, conventionally, no attempt has been made to carry out the granulation step continuously in the production of the electrostatic image developing toner by the emulsion polymerization aggregation method.
JP 2001-027821 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the background art, and the problem is that for electrostatic charge image development capable of obtaining a toner capable of obtaining a high-quality image because of high productivity and a narrow particle size distribution. The object is to provide a method for producing toner.

  As a result of intensive studies, the inventors of the present invention have studied the granulation conditions in various ways in the production of toner for electrostatic image development by the emulsion polymerization aggregation method, and devised the granulation apparatus to make the granulation process continuous. The productivity can be improved by making the granulation process continuous, and more surprisingly, it is possible to obtain a toner having a narrow particle size distribution compared to batch production methods. As a result, the present invention has been completed.

  That is, the present invention provides a method for producing a toner for developing an electrostatic charge image, wherein the toner particles are produced continuously in the method for producing a toner for developing an electrostatic charge image in which toner particles are produced in an aqueous medium. To do.

Further, the present invention provides at least steps (1), (2) and (3).
(1) Step of supplying a colorant and polymer primary particles to prepare a mixed dispersion (2) Step of supplying a mixed dispersion to form aggregated particles (3) Supplying aggregated particles to form fused particles A method for producing an electrostatic charge image developing toner having a forming step, wherein the static charge image developing toner includes a step of continuously supplying and a step of continuously extracting to any one of steps (1) to (3). The present invention provides a method for producing a toner for developing a charge image.

  According to the production method of the present invention, the general effects of the continuous production method such as high productivity can be obtained, as well as more stable particles such as a small particle size and a narrow particle size distribution. Therefore, it is possible to provide a toner for developing an electrostatic image capable of obtaining a high-quality image.

  Hereinafter, the method for producing the toner for developing an electrostatic charge image of the present invention will be described in detail. The present invention is characterized in that toner particles are continuously produced in a method for producing toner for developing an electrostatic charge image in which toner particles are produced in an aqueous medium. Here, “manually producing toner particles” means that all of the toner particle production steps may be continuous or a part thereof may be continuous.

  In the present invention, it is essential to produce toner particles in an aqueous medium (hereinafter, the production method is abbreviated as “wet method”). The wet method is a method for producing a toner for developing an electrostatic image using an aqueous dispersion medium such as water in the production process of toner particles. For example, (a) a polymerizable monomer in an aqueous medium, polymerization initiation A suspension polymerization method in which a toner particle is produced by suspending and dispersing an agent, a colorant, etc., and (b) emulsifying a polymerizable monomer in an aqueous medium containing a polymerization initiator, an emulsifier, etc. Emulsion polymerization in which toner particles are produced by adding a colorant or the like to a dispersion of polymer primary particles obtained by polymerizing a polymerizable monomer under stirring to aggregate and fuse the polymer primary particles. Aggregation method, (c) Dispersing a dispersion liquid (toner dispersion liquid of a toner composition) such as a polymer and a colorant previously dissolved and dispersed in a solvent in an aqueous medium, and removing the solvent by heating or reducing pressure. To produce toner particles dispersed in an aqueous medium. Suspension method.

  The present invention is not particularly limited as long as toner particles are continuously produced in at least a certain step in the method for producing toner by a wet method, and the wet methods such as the above (a), (b), (c), etc. Any of the toner particle production methods may be used, but (b) an emulsion polymerization aggregation method is preferred. Among the wet methods, the (b) emulsion polymerization aggregation method has an advantage that the circularity of the toner particles can be appropriately controlled. However, since the toner particles having a small particle size and a narrow particle size distribution are easily obtained in the first place, the present invention. The above effect (small particle size and narrow particle size distribution) is more preferable.

  Hereinafter, components commonly used in the wet toner particle production methods such as the above (a), (b), and (c), which are objects of the present invention, will be described.

Hereinafter, the binder resin used in the method for producing an electrostatic charge image developing toner of the present invention will be described.
<Binder resin>
The binder resin used for the toner in the present invention can be selected from a wide range including conventionally known ones. In the present invention, regardless of the method for producing the binder resin, the resin used is preferably a styrene-acrylate copolymer, a styrene-methacrylate copolymer, or an acrylic acid copolymer of these resins. Examples thereof include styrenic polymers such as polymers; saturated or unsaturated polyester polymers; epoxy polymers. In addition, the binder resin is not limited to being used alone, but two or more kinds can be used in combination. When using 2 or more types together, a low molecular weight component and a high molecular weight component may be mix | blended, and it may or may not contain a crosslinking component, respectively.

  When a toner is produced by an emulsion polymerization aggregation method, at least styrene is used as a copolymerization component, and at least one of acrylic acid, methacrylic acid, acrylic acid or alkyl ester of methacrylic acid is used as the copolymerization component. Is particularly preferred.

Hereinafter, the colorant used in the method for producing the toner for developing an electrostatic charge image of the present invention will be described.
<Colorant>
The colorant may be an inorganic pigment, an organic pigment, an organic dye, or a combination thereof. The colorant may be chromatic or achromatic.

  Specific examples of these include carbon black as an achromatic colorant, and cyan colorants, yellow colorants, and magenta colorants as chromatic colorants. Aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow, rhodamine dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dyes, monoazo, disazo, condensed azo dyes, etc. Arbitrary dyes and pigments can be used alone or in combination.

  In the case of a full color toner, benzidine yellow, monoazo, condensed azo dyes and the like are used as yellow colorants; quinacridone, monoazo dyes and pigments are used as magenta colorants; phthalocyanine blue is used as a cyan colorant. Is preferred. Specifically, as the cyan colorant, C.I. I. Pigment Blue 15: 3, and yellow colorants include C.I. I. Pigment yellow 74, C.I. I. Pigment Yellow 93 and magenta colorants include 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 is particularly preferably used.

  The content of the colorant is preferably in the range of 1 to 25 parts by weight, more preferably 1 to 15 parts by weight, and particularly preferably 3 to 12 parts by weight with respect to 100 parts by weight of the binder resin.

Next, the charge control agent used in the method for producing an electrostatic charge image developing toner of the present invention will be described.
<Charge control agent>
A charge control agent may be added to the toner used in the present invention in order to impart charge amount and charge stability. Conventionally known compounds are used as the charge control agent. The charge control agent may be either positively charged or negatively charged. For example, a hydroxycarboxylic acid metal complex, an azo compound metal complex, a naphthol compound, a naphthol compound metal compound, a nigrosine dye, Secondary ammonium salts and mixtures thereof.

  The content of the charge control agent is preferably in the range of 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts, and particularly preferably 0.1 to 2 parts by weight with respect to 100 parts by weight of the binder resin. is there.

Next, the wax component that can be used in the method for producing an electrostatic image developing toner of the present invention will be described.
<Wax>
For the toner used in the production method of the present invention, a wax can be used to improve fixability. Examples of the wax include 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; Plant waxes such as castor oil carnauba wax; ketones having long chain alkyl groups such as distearyl ketone; silicones having alkyl groups; higher fatty acids such as stearic acid; long chain aliphatic alcohols such as eicosanol; glycerin, pentaerythritol, etc. Carboxylic acid esters or partial esters of polyhydric alcohols obtained from polyhydric alcohols and long chain fatty acids such as stearic acid and montanic acid; higher fatty acid amides such as oleic acid amide and stearic acid amide; low molecular weight polyester There are exemplified. In the case of a carboxylic acid (partial) ester, a (partial) ester of a fatty acid having 15 to 30 carbon atoms and a 1 to 5 valent alcohol is 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.

  In order to improve the fixability among these waxes, the melting point of the wax is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, and particularly preferably 60 ° C. or higher. Moreover, 120 degrees C or less is preferable, 110 degrees C or less is more preferable, and 100 degrees C or less is especially preferable. If the melting point is too low, the wax tends to be exposed and sticky after fixing, and if the melting point is too high, the fixability at low temperatures is poor.

  The content of the wax is preferably in the range of 1 to 30 parts by weight, more preferably 2 to 20 parts, and particularly preferably 4 to 15 parts by weight with respect to 100 parts by weight of the binder resin.

  Next, a specific embodiment of the method for producing the toner for developing an electrostatic charge image of the present invention will be described in detail with respect to the above (b) emulsion polymerization aggregation method.

<Description of emulsion polymerization aggregation method>
The emulsion polymerization aggregation method is at least an emulsion polymerization step, and (1) a step of supplying a colorant and polymer primary particles to prepare a mixed dispersion (hereinafter referred to as “step (1)” or “mixing dispersion step”). (2) A step of supplying the mixed dispersion to form agglomerated particles (hereinafter abbreviated as “Step (2)” or “Aggregating step”), (3) Fusing particles by supplying the agglomerated particles (Hereinafter abbreviated as “process (3)” or “fusion process”) and a cleaning / drying process.

  That is, a dispersion containing polymer primary particles obtained by emulsion polymerization is mixed and dispersed with a colorant, if necessary, a particle such as a charge control agent, a wax or the like, or a dispersion thereof, and the particles in the dispersion are agglomerated. Then, if necessary, resin fine particles or the like are adhered to the particles, and then the aggregated particles or the agglomerated particles to which the resin fine particles or the like are adhered are fused, and the toner particles thus obtained are washed and dried to be static. A toner for developing a charge image is obtained.

<Emulsion polymerization process>
Below, an emulsion polymerization process is demonstrated.
<Emulsifier used for emulsion polymerization>
Examples of the emulsifier used in 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, sodium lauryl sulfate and the like.

  Furthermore, specific examples of nonionic surfactants include polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, monodecanoyl And sucrose.

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

<Production method of polymer primary particles>
The primary polymer particles used in the emulsion polymerization aggregation method preferably have a glass transition point (hereinafter sometimes abbreviated as “Tg”) of 40 to 80 ° C. and a volume average particle size of 0.02 to 3 μm. belongs to. The polymer primary particles are obtained by emulsion polymerization of a monomer. The production method is not particularly limited, but it is preferably obtained by seed emulsion polymerization of a monomer mixture using wax fine particles as a seed.

<Monomer used for emulsion polymerization>
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 “basic group”) may be used. ) And a monomer that does not have any Bronsted acidic group or Bronsted basic group (hereinafter, may be referred to as “other monomers”). At this time, the monomers may be added separately, or a plurality of monomers may be mixed and blended in advance. Further, it is possible to change the monomer composition during the monomer addition. Further, the monomer may be blended as it is, or may be blended as an emulsified liquid previously mixed and adjusted with water or an emulsifier. As the emulsifier, one or two or more combined systems are selected from the above surfactants.

  Examples of the “monomer having an acidic group” used in the present invention include monomers having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid and cinnamic acid; monomers having a sulfonic acid group such as sulfonated styrene. A monomer having a sulfonamide group such as vinylbenzenesulfonamide;

  Examples of the “monomer having a basic 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 and the like. Examples include (meth) acrylic acid esters having an amino group.

  Moreover, the monomer which has these acidic groups, and the monomer which has a basic group may exist as a salt with a counter ion, respectively. The blending ratio in the monomer mixture constituting the polymer primary particles of the monomer having an acidic group or basic group is preferably in the range of 0 to 10 parts by weight with respect to 100 parts by weight of the binder resin. Preferably it is 0-3 parts, Most preferably, it is 0-1.5 weight part. Among the monomers having an acidic group or a basic group, acrylic acid or methacrylic acid is particularly preferable.

  “Other monomers” include styrenes such as styrene, methylstyrene, chlorostyrene, dichlorostyrene, p-tert-butylstyrene, pn-butylstyrene, pn-nonylstyrene; methyl acrylate, acrylic acid Ethyl, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, ethyl hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hydroxy methacrylate (Meth) acrylic acid esters such as ethyl and ethylhexyl methacrylate; acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N-dipropylacrylamide, N, N-dibutylacrylic Amide, can be mentioned amides such as acrylamide. Of these, styrene, butyl acrylate and the like are particularly preferable.

<Crosslinking agent used for emulsion polymerization>
Furthermore, it is preferable to use a crosslinked resin for the polymer primary particles. In this case, it is preferable to use a crosslinking agent for the above-mentioned monomer. As the crosslinking agent, a polyfunctional monomer having radical polymerizability is used. For example, divinylbenzene, hexanediol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol diester. Methacrylate, neopentyl glycol acrylate, diallyl phthalate and the like can be mentioned. A monomer having a reactive group in a pendant group, such as glycidyl methacrylate, methylol acrylamide, or acrolein, can be used. Among these, radically polymerizable bifunctional monomers are preferable, and more specifically, divinylbenzene and hexanediol diacrylate are particularly preferable.

  The blending ratio of such a multifunctional monomer in the monomer mixture is preferably in the range of 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts, particularly preferably 100 parts by weight of the binder resin. Is 0.2 to 3 parts by weight.

<Glass transition point of polymer used for emulsion polymerization>
These monomers are used alone or in combination, and at that time, the glass transition point of the polymer is preferably 40 to 80 ° C. If the glass transition point exceeds 80 ° C., the fixing temperature may become too high, or the deterioration of OHP transparency may be a problem. On the other hand, if the glass transition point of the polymer is less than 40 ° C., toner storage stability May be worse. A more preferable glass transition point is 50 to 70 ° C, and a particularly preferable glass transition point is 55 to 65 ° C.

<Polymerization initiator and chain transfer agent used for emulsion polymerization>
The polymerization initiator may be added to the polymerization system at any time before, simultaneously with, and after the monomer addition, and these addition methods may be combined as necessary. The content of the initiator is preferably in the range of 0 to 10 parts by weight, more preferably 1 to 7 parts by weight, and particularly preferably 2 to 5 parts by weight with respect to 100 parts by weight of the binder resin. 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. , Carbon tetrachloride, trichlorobromomethane, and the like. The chain transfer agent may be used alone or in combination of two or more.

<Emulsion polymerization temperature>
In the emulsion polymerization, the above monomers are mixed with water and polymerized in the presence of a polymerization initiator or the like. The polymerization temperature is usually 40 to 150 ° C, preferably 50 to 120 ° C, more preferably 60 to 100 ° C. is there.

<Particle size of primary particles made by emulsion polymerization>
The volume average particle size of the polymer primary particles thus obtained is usually in the range of 0.01 μm to 3 μm, preferably 0.02 μm to 2.5 μm, more preferably 0.05 μm to 2 μm, particularly preferably. 0.1 μm to 1.5 μm. The average particle diameter can be measured using, for example, UPA. When the particle size is smaller than 0.02 μm, it may be difficult to control the aggregation rate. On the other hand, if the particle diameter is larger than 3 μm, the toner particle size obtained by agglomeration tends to be large, and may be unsuitable for producing a toner of 3 to 8 μm.

  It is preferable to mix a dispersion of polymer primary particles and a colorant to obtain a mixed dispersion, and then co-aggregate to obtain aggregated particles. The colorant is preferably emulsified in water and used in the form of an emulsion in the presence of an emulsifier (the aforementioned surfactant) in advance. The volume average particle size of the colorant particles is preferably 0.01 to 3 μm, more preferably 0.05 μm to 2 μm, and particularly preferably 0.1 μm to 1 μm. The amount of the colorant used is usually 1 to 25 parts by weight, preferably 1 to 15 parts by weight, and more preferably 3 to 12 parts by weight with respect to 100 parts by weight of the polymer primary particles.

<Wax>
In the toner manufacturing method of the present invention, it is preferable to use wax. If no wax is added, the fixability may deteriorate, and the paper may wrap around the fixing roll during fixing. As the wax, the same wax as that described in the above-mentioned “components commonly used in the wet method for producing toner particles” is preferably used. In the emulsion polymerization flocculation method, paraffin wax is particularly preferable because the property is appropriately changed with respect to heat, so that flocculation can be easily controlled in the flocculation step.

  In the emulsion polymerization agglomeration method, the wax is dispersed in the presence of an emulsifier (the surfactant) in advance to form an emulsified wax fine particle dispersion, which is then used as a seed for emulsion polymerization to produce polymer primary particles encapsulating the wax. There is no limitation as it may be used for production and for co-aggregating the wax fine particle dispersion with the polymer primary particles (which may contain wax) and the colorant in the coagulation step. . In the toner manufacturing method of the present invention, it is preferable to perform seed polymerization using wax as a seed, and use polymer primary particles enclosing the wax. That is, it is preferable that the polymer primary particles used in the toner production method of the present invention include seed polymer particles using wax as a seed because the wax can be prevented from being exposed on the surface of the toner particles.

  The average particle size of the wax microparticles is common to both the case of using as a seed and the case of coaggregation, and is preferably 0.01 μm to 3 μm, more preferably 0.1 to 2 μm, and particularly preferably 0.1 to 1.5 μm. Those are preferably used. In addition, an average particle diameter can be measured using the Horiba LA-500, for example. When the average particle size of the wax emulsion is larger than 3 μm, it may be difficult to control the particle size during aggregation. In addition, when the average particle size of the emulsion is smaller than 0.01 μm, it may be difficult to prepare a dispersion.

<Charge control agent>
In the toner manufacturing method of the present invention, it is preferable to use a 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, or the charge control agent is dissolved or dispersed in a monomer or wax, or an aggregation step. Thus, the primary particles of the polymer and the colorant are aggregated together with the primary particles of the charge control agent to form aggregated particles, or the primary particles of the polymer and the colorant are aggregated to obtain an appropriate particle size as toner particles. Later, primary particles of the charge control agent can be added and agglomerated. In these cases, the charge control agent is preferably dispersed in water using the aforementioned surfactant and used as an emulsion (primary particles of charge control agent) having an average particle size of 0.01 to 3 μm, more preferably 0.8. A thing of 05-2 micrometers, especially 0.1-1 micrometer is used suitably.

<Container used for emulsion polymerization process>
In the polymerization step of the polymer primary particles used in the present invention, a polymerization vessel usually used for emulsion polymerization can be suitably used.

The method for continuously producing toner particles according to the present invention includes at least steps (1), (2) and (3) in the emulsion polymerization aggregation method (b).
(1) Step of supplying a colorant and polymer primary particles to prepare a mixed dispersion (mixed dispersion step)
(2) Supplying the mixed dispersion to form aggregated particles (aggregation process)
(3) Step of supplying aggregated particles to form fused particles (fused step)
It is preferable that the method includes a step of continuously supplying and a step of continuously extracting to any one of steps (1) to (3).

  Any of the steps (1) to (3) may be continuous. Preferably, at least the step (2) includes a step of continuously supplying and a step of continuously extracting. That is, a method for producing a toner for developing an electrostatic charge image in which the step (2) includes a step of continuously supplying the mixed dispersion and a step of continuously extracting the aggregated particles is preferable. In addition, it is more preferable that the step (3) also includes a step of continuously supplying and a step of continuously extracting. In addition, a step of continuously supplying and continuous step (1) What has the process of extracting to is still more preferable.

<Step (1) mixing and dispersing step>
In the mixing and dispersing step, at least the above-described colorant and polymer primary particles, and if necessary, the above-described wax, charge control agent, other components and the like are mixed and dispersed. The mixing and dispersing step is necessary to make the liquid supplied to the aggregation step uniformly dispersed. The polymer primary particles are supplied to the mixing and dispersing step with the dispersion obtained in the emulsion polymerization step. Each of the above components other than the polymer primary particles may be in the form of particles or in a state of being dispersed in a dispersion medium in advance, but each component can be uniformly supplied to the mixing and dispersing step as a dispersion. It is preferable at the point disperse | distributed.

  The dispersion medium is not limited as long as it is an aqueous medium, but is preferably water. The dispersion concentration is not particularly limited, but is usually 3% by mass or more, preferably 7% by mass or more, more preferably 10% by mass or more, and usually 40% by mass or less, preferably 30% by mass or less, as the solid content concentration. More preferably, it is 20 mass% or less. When the dispersion concentration is less than the above range, it may be difficult to control the particle size and particle size distribution, and when the dispersion concentration exceeds the above range, uniform dispersion may not be achieved due to thickening.

  The container used in the mixing and dispersing step is not particularly limited, and an ordinary reactor or the like is used. However, the container preferably has a stirring blade in order to increase mixing efficiency. The shape of the stirring blade is not particularly limited as long as it can be uniformly mixed and dispersed, but an anchor blade is preferable. In the case where the step (1) is continuously performed, those having a supply port for continuous supply and an extraction port for continuous extraction are used.

<Process (2) aggregation process>

  In the aggregation step, at least the above-described colorant and polymer primary particles, and if necessary, the above-described wax, charge control agent, other components, and the like are aggregated. In the aggregation process, the toner particles are aggregated to approximately the size of the toner particles prior to the fusing process. Each of the above components other than the polymer primary particles may be in the form of particles or in a state of being dispersed in a medium in advance, but as a dispersion, for example, in the form of a slurry or an emulsion, the container for aggregation may be used. It is preferable to supply in order to appropriately adjust the residence time of the aggregation process. In addition, when each component is supplied in the form of particles instead of being made into a slurry or emulsion, secondary agglomeration may occur and coarse powder may be generated in the toner, resulting in white streaks in the resulting image. There is.

  In the coagulation step, the volume average particle diameter of each of the above components is preferably 3 μm or less, particularly preferably 1 μm or less, and further preferably 0.5 μm or less, and it is desirable to supply in the state of an aqueous dispersion. By supplying with an aqueous dispersion in the particle size range, it becomes easier to control the average particle size and particle size distribution of the aggregated particles, or the charge distribution of the obtained toner becomes sharp and an image free from fogging is obtained. It may be preferable above.

  When step (2) is continuously performed, each component may be supplied to an empty container at the initial stage of continuous operation. However, a dispersion medium not containing particles or the like is filled in the container in advance, and each component is supplied to this. May be supplied to stabilize the component concentration in the container. In addition, one or several of each component may be filled in a container in advance, and the component concentration in the container may be stabilized by supplying each component to the container. A condensate similar to the state may be produced by another method, and the components concentration in the container may be stabilized by supplying each component in a state where the liquid is filled in the container. In the step (2), each of the above components is supplied to a container and aggregated by, for example, heating, pH adjustment, salt addition, curing agent addition, or the like.

  The temperature at which the step (2) is carried out by heating is preferably at least 10 ° C lower than the glass transition point of the polymer primary particles, more preferably at least 5 ° C lower than the glass transition point. Moreover, the temperature below 10 degreeC higher than the glass transition point of a polymer is preferable, and the temperature below 5 degreeC is more preferable. When the temperature is less than the above range, the target particle size may not be reached. When the temperature is over the above range, it may be larger than the target particle size. Here, when there is a distribution in temperature in the aggregation process, the average value of the maximum temperature and the minimum temperature is set.

  The residence time in the container when the aggregation step is performed by heating is preferably 2 hours or less, and particularly preferably 1 hour or less, from the viewpoint of production efficiency, as the average residence time during which each component is placed under the temperature conditions. By such heat treatment, the above-described colorant and polymer primary particles, and, if necessary, the above-described wax, charge control agent, other components and the like are integrated. Here, when the supply timing of the supply component to a container differs, it is set as the time from the time of supplying a component first. The supply rate is not particularly limited, but is preferably 5 to 80 mL / min, and particularly preferably 10 to 60 mL / min.

  In the step (2), the temperature can be set to the above-mentioned temperature so that the agglomeration can be carried out without containing the electrolyte, but the agglomeration containing the electrolyte is also preferred. When agglomerating with an electrolyte, it can also be carried out at the temperature or lower. The step of actually supplying the electrolyte may be either step (1) and / or step (2). That is, the electrolyte may be supplied in advance in step (1).

The electrolyte that can be used in the step (2) may be either an organic salt or an inorganic salt, and the valence is not particularly limited, but is preferably divalent or higher. 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 , CH ₃ COONa, C ₆ H ₅ SO ₃ Na, and the like. Of these, inorganic salts having a divalent or higher polyvalent metal cation are particularly preferred. By using the electrolyte, it becomes easy to control the average particle size and particle size distribution of the aggregated particles, the charge amount distribution of the obtained toner becomes sharp, and an image free from fogging can be obtained.

  The content of the electrolyte varies depending on the type of electrolyte and the particle size of the intended aggregated particles, but is usually 0.05 to 25 parts by weight, preferably 0.05 with respect to 100 parts by weight of the solid component of the mixed dispersion. -15 parts by weight, more preferably 0.05-10 parts by weight. When aggregation is performed by adding an electrolyte, if the electrolyte content is less than the above range, the progress of the agglutination reaction is delayed, and a fine powder of 1 μm or less remains after the agglomeration reaction, and the average of the obtained aggregated particles In some cases, the particle size may not reach the target particle size. When the particle size exceeds the above range, rapid aggregation is likely to occur, and it becomes difficult to control the particle size. Problems such as inclusion of coarse powder or irregular shapes may occur.

  When the aggregation is performed by adding the electrolyte, the aggregation temperature is preferably at least 20 ° C. lower than the glass transition point of the polymer primary particles, more preferably at least 10 ° C. lower. Moreover, the temperature below 10 degreeC higher than the glass transition point of a polymer is preferable, and below the glass transition point of a polymer is more preferable. In the present invention, the temperature control in the aggregation process is important for controlling the average particle size and particle size distribution of the obtained aggregate, and therefore the difference between the maximum temperature and the minimum temperature in the aggregation process is preferably within 20 ° C. It is particularly preferable that the temperature is within the temperature. When the difference between the maximum temperature and the minimum temperature exceeds the above range, the particle size control may be difficult.

In step (2), it is desirable to form aggregated particles with a shearing force of preferably 100 s ⁻¹ or more, particularly preferably 200 s ⁻¹ or more, more preferably 300 s ⁻¹ or more. Here, the shear rate means the shear rate of the portion showing the highest value among the shear rates of the apparatus determined by the shape of the apparatus such as the container and the stirrer, the operating conditions, the component configuration, and the like. When the shear rate is less than the above range, the particle size distribution may be deteriorated, and when the shear rate is low, the particle size distribution may be broad.

  In step (2), the colorant and polymer primary particles, and if necessary, a mixed dispersion of wax, charge control agent, and other components may be supplied substantially simultaneously to form aggregated particles. In addition, at least one selected from the group consisting of resin fine particles, a colorant, a wax, and a charge control agent may be further supplied to the dispersion of aggregated particles aggregated to have a volume average particle diameter of 1 μm or more.

<Process (3) Fusion process>
In step (3), by heating the aggregate obtained in step (2), the colorant and polymer primary particles, and if necessary, wax, charge control agent, other components, etc. are fused together. , Physically one particle.

  In the step (3), it is preferable to form fused particles by applying a temperature higher than the glass transition point of the polymer primary particles. Furthermore, the temperature in the step (3) is preferably 10 ° C. or more, more preferably 20 ° C. or more higher than the glass transition point of the polymer primary particles. Moreover, the temperature below 80 degreeC higher than the glass transition point of a polymer is preferable, and the temperature below 60 degreeC is more preferable. If the temperature is less than the above range, the residence time at the time of fusion may be too long, the device may be enlarged and the production efficiency may be reduced.If the temperature is above the range, the shape control of the aggregated particles is difficult. There is a case. Here, when there is a distribution in the temperature in the fusion process, the average value of the maximum temperature and the minimum temperature is set.

  In the step (3), the average residence time during which the aggregated particles are placed in the temperature condition is preferably 2 hours or less, particularly preferably 1 hour or less, from the viewpoint of production efficiency. By such heat treatment, the polymer primary particles, the colorant, and the like are fused and integrated, and the fused particle shape, that is, the toner particle shape is also close to a spherical shape. Moreover, it is preferable for the said reason that the container internal temperature of an extraction port is more than the container internal temperature of a supply port.

  When the step (3) is continuously performed, the dispersion liquid in which the fused particles obtained in the step (3) are dispersed is continuously extracted from the container.

<Relationship between Step (2) Aggregation Step and Step (3) Fusion Step>
The container used in the step (2) and the container used in the step (3) may be (a) integrated, (b) connected to each other, and (c) via a transfer pipe. (B) or (c) is preferable. That is, it is preferable that at least two or more containers are connected in series. In the case of (b), aggregation and fusion can be achieved by controlling the temperature conditions and shearing force of the step (2) and the step (3) of the container, and in the case of (c) By transferring to a container (container in step (3)), the temperature can be raised and fusion can be performed. If they are integrated as shown in (a), the step (2) agglomeration step and the step (3) fusion step cannot be clearly separated, and the fusion temperature in step (3) extends to step (2). In some cases, an appropriate aggregation temperature cannot be obtained.

  It is preferable that the temperature in at least one container in the step (3) is higher than the temperature in the container in the step (2). The temperature of the step (3) is preferably higher than the temperature of the step (2) by preferably 0 to 60 ° C or more, particularly preferably 5 to 40 ° C or higher. In step (2), if the residence time is not long at a certain low temperature, the particle size may not be adjusted due to a slight deviation in the flow rate of the pump, etc. In short, if the temperature is lower than that in step (2), the container may become too large.

<Washing and drying process>
The fused particles obtained through each of the above steps are subjected to solid-liquid separation according to a known method, and the fused particles are recovered, then washed as necessary and then dried. Toner particles can be obtained. In this way, a toner for developing an electrostatic charge image having a volume average particle diameter of, for example, 3 to 8 μm and a relatively small particle diameter can be produced. In addition, the toner thus obtained has a sharp particle size distribution and charge amount distribution, and is suitable as an electrostatic image developing toner for achieving high image quality and high speed.

<Outer layer formation>
In addition, the surface of the fused particles obtained by the emulsion polymerization aggregation method is further composed of a polymer as a main component by a method such as a spray drying method, an in-situ method, or a submerged particle coating method. Encapsulated toner particles can be obtained by forming the outer layer preferably with a thickness of 0.01 to 0.5 μm.

  In the spray drying method, for example, a polymer fine particle emulsion for forming an outer layer is added to an emulsion of fused particles, the both are mixed, and the emulsion mixture is sprayed and dried to form an outer layer. it can. In the in-situ method, for example, a polymerizable monomer and a polymerization initiator constituting a polymer for forming an outer layer are added to the fused particle emulsion obtained above and adsorbed on the fused particle surface. The outer layer can be formed by heating and polymerizing the polymerizable monomer. In the submerged particle coating method, for example, an outer layer-forming polymer fine particle emulsion is added to the emulsion of fused particles obtained above, and both are stirred and mixed to react or bond with each other. Can be formed.

  At that time, the polymer fine particles forming the outer layer are preferably produced by the same emulsion polymerization aggregation method as described above. The glass transition point of the outer layer polymer in these encapsulated toner particles is preferably 70 ° C. to 110 ° C., and preferably higher than the glass transition point of the polymer constituting the fused particles.

<External additive>
Further, a known external additive may be added to the toner particles 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 content of the external additive is preferably in the range of 0.05 to 5 parts by weight with respect to the toner particles.

<Toner type>
The electrostatic image developing toner obtained by the production method of 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.

<Career>
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 size of the carrier is not particularly limited, but preferably has an average particle size of 10 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 electrostatic image developing toner.

<Particle size of toner for developing electrostatic image>
As the particle diameter of the toner for developing an electrostatic image, a value measured as an aperture diameter of 100 mm using a precision particle size distribution measuring device Coulter Counter Multisizer II manufactured by Beckman Coulter Inc. is used. By the production method of the present invention, a toner having a volume average particle diameter (Dv) of 3 to 8 μm can be obtained efficiently. Therefore, the production method of the present invention is preferably used for producing a toner for developing an electrostatic charge image having a volume average particle diameter of 3 to 8 μm, particularly preferably for 4 to 8 μm, and more preferably for 4 to 7 μm. If the volume average particle size is too large, it is not suitable for high-resolution image formation, and if it is too small, handling as a powder becomes difficult. If the volume average particle size is too large, the batch method is sufficient even if the production method of the present invention is not used, so that the above-described effects of the present invention may not be obtained.

<Average circularity of toner>
The average circularity of the toner is preferably 0.9 to 1, more preferably 0.92 to 0.99, and particularly preferably 0.94 to 0.98. In the present invention, the average circularity is measured by a flow type particle image analyzer FPIA-2000 manufactured by Sysmex Corporation, and the circularity is obtained from the following formula, and the circularity in the case where the cumulative particle size value corresponds to the number 50%. .
Circularity = circumference of a circle with the same area as the projected particle area / circumference of the projected particle image

<Containers and production conditions used in the present invention>
Next, the container used for this invention and manufacturing conditions are demonstrated in detail. The shape of the continuous aggregator used in the step (2) in the present invention is not limited, and general stirring and mixing containers can be suitably used. Among them, (high-speed rotation) cylindrical mixing A granulator is preferred. When a high-speed rotating cylindrical mixer is used, it is easy to satisfy the conditions for the shear rate and the conditions for the number of tank rows described below.

  It is desirable that the number of tank rows in the complete mixing tank row model is 2 or more, preferably 3 or more, more preferably 4 or more in the container used in the step (2) in the present invention. If the number of tank rows is less than the above range, the particle size distribution of the obtained toner particles may be wide. Here, the number of tank rows in the complete mixing tank row model is defined as described in Nobuo Ohtake, Chemical Engineering III, 2nd edition, Iwanami Zensho, pages 102-104. In the present invention, it is calculated from the change in the pigment concentration in the obtained aggregated particles at the initial pigment addition. Since the number of tank rows of the container may change depending on the operating conditions, it is preferable to operate so that the number of tank rows can fall within the above range using a container that can fall within the above range.

  Although there is no limitation in particular about the stirring blade of the container used for a process (2), it is preferable to use the mixer whose stirring blade is a cylindrical type or a multiple cylinder parallel type. One stirring blade or two or more stirring blades used in step (2) can be used in parallel. Among them, one stirring blade is preferable. In order to achieve the shear rate, when the container length is fixed, the smaller the effective volume in the container, the better.

The container used in the step (2) preferably has a ratio of the cross-sectional area S _{1 of the} container and the cross-sectional area S ₂ of the stirring blade shaft satisfying (S ₁ / S ₂ ) ≦ 20, and S ₁ / It is particularly preferable that S ₂ ≦ 10 is satisfied. Here, if there are multiple stirring blade, S ₂ denotes the total value of the maximum cross-sectional area of each stirring blade axis. When this is satisfied, it is preferable in that convection hardly occurs.

Further, the container used in the step (2) has a ratio of the diameter d _{1 of the} equivalent circle having the same area as the liquid passage effective area (S ₁ -S ₂ ) to the length L of the container (d ₁ / L) ≦ 2 is preferable, and further, d ₁ / L ≦ 1 is particularly preferable. When satisfying this, the residence time of the liquid for a certain time or more can be secured, and the particle size can be easily controlled.

  The reason why the above-mentioned “conditions relating to the shape of the container” is preferable is not clear, but when a cylindrical shape or a tower shape is used and it is installed in a vertical direction, it is in accordance with the pressure from below in terms of preventing vertical convection. It is presumed that there is an effect that the fluid moves smoothly upward without flowing backward.

  The stirring speed (rotational speed) of the stirring blade is not particularly limited, but is preferably 50 rpm to 1000 rpm, and particularly preferably 100 rpm to 800 rpm.

An example of a stirring blade (25) used in step (2) shown in FIG. Although the shape of the stirring blade (25) is not specified, a pin type (26a) or an anchor type (26b) is preferable. The pins (26a) of the pin type blades can be provided in 4 to 10 rows, preferably 6 to 8 rows, on the circumference of the stirring blade shaft (25). It is further preferable to install a similar pin baffle (not shown in FIG. 2 ) on the inner wall of the vessel of the step (2), together with the pin (26a) of the pin type wing. The rows of the pin baffles are preferably arranged so as to be equally spaced from each other, and the arrangement of the pin baffles is shifted from each other at the upper and lower positions of the adjacent rows of pin baffles ( It is preferable from the viewpoint of uniform mixing as a whole.

  In addition, the pin-type baffle rods can also be arranged offset so as to draw a spiral in the circumferential direction. In this case, the circumferential row of the pin-type baffle rods with respect to the rotation direction of the stirring blade shaft (17) It is preferable from the viewpoint of preventing convection that the force applied to the fluid is inclined upward.

The anchors of the anchor blades are preferably provided in 2 to 8 rows on the circumference of the stirring blade shaft (25). The shape of its wings, the ratio of the sectional area S ₂ of the sectional area S ₁ and the stirring blade axis of the container (25) is larger likely than when using a pin-type blades, there is a case where convection is likely to occur Therefore, the pin type is preferable. Moreover, the thing provided with the pin-type wing | blade from the point which is easy to take out the shear force of a preferable range is preferable.

  A propeller-type partition plate can also be disposed at the junction of each stage of the reaction. In this case, it is preferable that the propeller is integrated with the rotation direction of the mandrel and is arranged in a direction in which the fluid is pushed upward.

  Moreover, it is preferable that at least 1 of the extraction port of this container is installed in the upper part rather than the lowest supply port for the container used for a process (2) in this invention. In the case where at least a part of the flow direction in the container is in a direction opposite to the gravity, it is preferable because the stirring efficiency is good, and when filling the liquid in which particles are dispersed in the initial stage of operation into an empty container, It is preferable because the generation of coarse powder due to drying of liquid droplets on the inner wall of the container can be prevented. In addition, it is preferable because there is an advantage that bubbles are easily removed and it does not take time to stabilize.

  In the present invention, the dispersion liquid that has undergone the step (1) is transferred through a pressure medium such as a pump so as to antagonize the gravity in the container of the step (2) and adjust the residence time sufficiently. Here, when the cylindrical type or the tower type is used, the installation angle of the reactor can be used that is inclined within a range of 40 degrees from a right angle with respect to the horizontal plane.

  The container used in the step (2) is also preferably divided into a plurality from the viewpoint of temperature control (22a to 22d), and at that time, the downstream container temperature may be equal to or higher than the upstream container temperature. From the viewpoint of easy control of the particle size.

  Although the material of the container used for the process (2) in this invention is not limited, It is preferable that the inner surface of a container is substantially stainless steel and / or glass. In particular, smooth stainless steel and / or glass are preferable. When the inner surface of the container is made of the above material, it is preferable that the supplied components, the aggregated particles in the step (2), the fused particles in the step (3) can be prevented from adhering to the container wall surface. There is.

  In the present invention, the container for performing the step (2) and the container for performing the step (3) may be integrated or may be composed of different containers, but are preferably composed of different containers. In particular, it is preferable that at least two or more containers are connected in series. That is, it is preferable that the container for performing the step (2) and the container for performing the step (3) are connected in series. Such a configuration is desirable because the step (2) and the step (3) can be clearly divided and the operating conditions of each step can be optimized. Even when the container for performing the step (2) and the container for performing the step (3) are integrated in shape, the steps (2) and (3) are substantially controlled by the partition walls, stirring conditions, flow control, and the like. Are preferably designed to be made in different regions. In the present invention, when step (1), step (2), and step (3) are performed in separate containers, an outlet for measuring and controlling the particle size may be provided at the inlet or outlet of each container. it can. Moreover, the apparatus which monitors the viscosity inside each container can also be provided.

  In the present invention, from the viewpoint of optimization which is important for the benefit of the continuous process, it is necessary to accurately determine the end of the agglomeration process and shift to the fusion process. The end of the agglomeration process can usually be determined by the inflection point of the viscosity change. That is, in the aggregation process, as the aggregation starts, a network is formed between the particles and the viscosity increases, but when reaching a certain saturation point, the viscosity decreases. At this inflection point, the completion point of the aggregation can be found, and the process up to the end of the aggregation can be controlled by optimizing the thermal history and residence time in the cascade reactor as in the present invention. It is a continuous process feature of the present invention.

  Moreover, in this invention, 2 or more types of polymer primary particles from which a composition and / or an average particle diameter differ can be used. There is no limitation on the supply method in the case of using different primary polymer particles together, and they may be mixed in advance in step (1) and supplied to step (2) at the same time, from the same supply port or different supply ports. The process (2) may be supplied at the same time, or may be supplied from different supply ports at different times in the process (2). Furthermore, one or more kinds of polymer primary particles can be supplied before step (3) after step (2) or before step (3). Among these, it is preferable to supply from different supply ports at different times in the step (2). By supplying from different supply ports, aggregated particles having different compositions between the inner and outer shell portions can be obtained, and the toner performance and the like may be improved. When different polymer primary particles are used to obtain aggregated particles having such a structure, the polymer primary particles constituting the outer shell portion have a higher Tg than the polymer primary particles used in step (2). Is preferably used.

  In the present invention, as described above, when using a device in which at least two containers are connected in series, it is preferable that the temperature of at least one container is higher than the temperature of the upstream container. . Furthermore, it is preferable to have at least one container that is 20 ° C. higher than the glass transition point of the polymer primary particles downstream of the container that is 20 ° C. higher than the glass transition point of the polymer primary particles. . In such a condition, in the step (2), the average particle size and particle size distribution of the aggregated particles can be easily controlled and the production efficiency is improved. In the step (3), the average of the fused particles is obtained. It is preferable because the particle size, particle size distribution, and circularity can be easily controlled and the production efficiency is improved.

  In summary, what is important in the present invention is as follows. That is, a cylindrical or tower-shaped structure is used as the container, the action of gravity is added to the fluid, the number of stages allowing temperature gradient can be set, and the supply port and the discharge port can be arbitrarily set The number of stages can be set, the space in the vessel that serves as the reaction field should have a cross section within the specified range, and the above conditions ensure the residence time during which the particles are subjected to a thermal history so that aggregation is fully completed It is possible to set the shearing force.

  When the production method of the present invention is used, the effects of the continuous method in general, such as higher production efficiency than the batch method, can be obtained, and in addition, “manufacturing toner particles with an aqueous medium” according to the present invention. And “manufacturing continuously” unexpectedly, the performance unique to the polymerized toner such as a sharp charge distribution and a sharp particle size distribution could be further improved. Although such an action and principle are not clear, it is considered that the agglomeration is uniform at a level that cannot be achieved by the batch method, particularly by aggregating continuously.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples. In the following examples, “parts” means “parts by weight”.

<Measurement method>
The average particle diameter, weight average molecular weight, glass transition point (Tg), average circularity, fixing temperature width, OHP permeability, charge amount, blocking resistance and melting point of the wax were measured by the following methods.

[Volume average particle diameter, number average particle diameter, ratio of toner particles of 5 μm or less and 15 μm or more]
Measurement was carried out with an aperture diameter of 100 nm using LA-500 manufactured by Horiba, Microtrac UPA (ultra particle analyzer) manufactured by Nikkiso Co., Ltd., and Coulter Counter Multisizer II type (hereinafter abbreviated as “Coulter Counter”) manufactured by Coulter.

[Weight average molecular weight (Mw), molecular weight peak (Mp)]
Measured by gel permeation chromatography (GPC).
Apparatus: GPC apparatus manufactured by Tosoh Corporation HLC-8020
Column: PL-gel Mixed-B 10μ made by Polymer Laboratory
Solvent: Tetrahydrofuran (THF)
Sample concentration: 0.1% by mass
Calibration curve: Standard polystyrene

[Glass transition point (Tg)]
It was measured by DSC7 manufactured by PerkinElmer. The temperature was raised from 30 ° C. to 100 ° C. in 7 minutes, rapidly cooled from 100 ° C. to −20 ° C., heated from −20 ° C. to 100 ° C. in 12 minutes, and the Tg value observed at the second temperature rise was Using.

[Average circularity]
Measured with a flow type particle image analyzer FPIA-2000 manufactured by Sysmex Corporation, the degree of circularity was determined from the following formula, and the degree of circularity corresponding to a cumulative particle size value of 50% was defined as the average degree of circularity.
Circularity = circumference of a circle with the same area as the projected particle area / circumference of the projected particle image

[Fixing temperature range]
Recording paper carrying an unfixed toner image was prepared, the surface temperature of the heating roller was changed from 100 ° C. to 220 ° C., conveyed to the fixing nip portion, and the fixing state when discharged was observed. The temperature range where the toner on the heating roller did not offset during fixing and the toner on the recording paper after fixing was sufficiently adhered to the recording paper was defined as the fixing temperature range.

[Tetrahydrofuran insoluble matter]
The tetrahydrofuran insoluble content of the toner, polymer primary particles, and resin fine particles was measured by adding 1 g of a sample to 100 g of tetrahydrofuran, allowing the mixture to stand at 25 ° C. for 24 hours, filtering through 10 g of Celite, and distilling off the solvent of the filtrate. Tetrahydrofuran soluble content was quantified and subtracted from 1 g to calculate tetrahydrofuran insoluble content.

[Melting point of wax]
Using a DSC-20 manufactured by Seiko Instruments Inc., measurement was performed at a heating rate of 10 ° C./min, and the temperature at the top of the peak showing the maximum endotherm in the DSC curve was taken as the melting point of the wax.

Example 1
[Preparation of Wax Dispersion-1 (PER)]
68.33 parts of demineralized water, 30 parts of stearic acid ester of pentaerythritol (Unistar H476, manufactured by NOF Corporation) and 1.67 parts of Neogen SC are mixed and emulsified by applying high-pressure shear at 90 ° C., and dispersion of ester wax fine particles Got. The average particle diameter of the ester wax fine particles measured by LA-500 was 350 nm.

[Preparation of Polymer Primary Particle Dispersion-1 (TP-049)]
A reactor (capacity 60 liters, inner diameter 400 mm) equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and each component / auxiliary charging device, 28 parts of wax dispersion-2, 15% neogen SC 1.2 parts of an aqueous solution and 393 parts of demineralized water were charged, the temperature was raised to 90 ° C. under a nitrogen stream, and 1.6 parts of an 8% aqueous hydrogen peroxide solution and 1.6 parts of an 8% aqueous ascorbic acid solution were added.

  Thereafter, the following monomers, a chain transfer agent, a mixture of a crosslinking agent and an aqueous emulsifier solution were added over 5 hours from the start of polymerization, and the initiator aqueous solution was added over 6 hours from the start of polymerization, and the mixture was further maintained for 30 minutes. The number of copies is the number of copies actually used.

[Monomer, chain transfer agent, cross-linking agent]
76 parts of styrene (6600g)
Butyl acrylate 24 parts Acrylic acid 3 parts Bromotrichloromethane 0.3 part 2-mercaptoethanol 0.01 part Hexanediol diacrylate 0.79 part [emulsifier aqueous solution]
15% Neogen SC aqueous solution 1 part Demineralized water 25 parts [Initiator aqueous solution]
8% hydrogen peroxide aqueous solution 9 parts 8% ascorbic acid aqueous solution 9 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer dispersion. The weight-average molecular weight of the THF soluble part of the polymer was 211,000, the average particle size measured by UPA was 193 nm, and Tg overlapped with the melting point of the wax and was unclear, but it was between 55-60 ° C.

[Colorant fine particle dispersion-1]
Pigment Blue 15: 3 aqueous dispersion (EP-700 Blue GA, manufactured by Dainichi Seika, 24% active ingredient) The average particle size measured by UPA was 150 nm.

<Manufacture of developing toner-1>
(apparatus)
As shown in FIG. 1, the apparatus is composed of three mixers (11a) (11b) (51), a continuous aggregator (21), and a continuous fuser (41). The aggregator (21) and the continuous fuser (41) are connected by a liquid supply hose (53) provided with a pump (54). A stirrer (12a) (12b) (52) is installed in each mixer, and a stirrer (29) is installed in the continuous aggregator (21).

(Process (1))
In a 10 mL first mixer (11a) containing an anchor stirring blade (13a), a polymer primary particle dispersion (solid content concentration 20%) is added at a rate of 26.5 mL / min. (Solid content concentration 20%) was continuously fed and mixed at a rate of 1.2 mL / min. The residence time in the first mixer (11a) is 20 seconds. The internal temperature of the 1st mixer (11a) was 20 degreeC, and the rotational speed of the stirring blade (13a) was 400 rpm.

  The mixed dispersion 1 exiting from the first mixer (11a) is continuously supplied to the second mixer (11b) having a capacity of 20 CC incorporating the anchor stirring blade (13b), and at the same time, the second mixer (11b). Was continuously fed with an aluminum sulfate solution (solid concentration 0.5%) at a rate of 6 mL / min and mixed in the second mixer (11b). The residence time in the second mixer (11b) is 35 seconds. The internal temperature of this 2nd mixer (11b) was 20 degreeC, and the rotational speed of the stirring blade (13b) was 400 rpm.

(Process (2))
As the continuous aggregator (21) in FIG. 1, a continuous aggregator (21a) having a pin-type blade was used. The pin type wing continuous aggregator (21a) was made of glass with a jacket, had an inner diameter of 50 mm, and a length of 50 mm × 4 stages = 200 mm. The diameter of the stirring blade shaft (27) was 32 mm, the length of the pin-type blade was 7 mm, and the distance between the blade tip and the inner wall of the container was 2 mm.

  The mixed dispersion 2 discharged from the second mixer (11b) contains a pin stirring blade (25) and has a capacity of 290 mL (= excluding the stirring blade) having a four-stage structure (22a to 22d) as a temperature control unit. To the continuous agglomerator (21a) at a rate of 34 mL / min. The residence time in the continuous aggregator (21a) was 9 minutes. The internal temperature of the first stage (22a) and the second stage (22b) of the continuous aggregator (21a) is set to 50 ° C, and the internal temperature of the third stage (22c) and the fourth stage (22d) is set to 65 ° C. The stirring speed was 500 rpm. The particle size of the agglomerated liquid 1 extracted from the continuous aggregator (21a) was measured with a Coulter counter. The volume average particle size was 7.7 μm, and the ratio of the volume average particle size to the number average particle size was 1.15. there were.

(Mixing between steps (2) and (3))
The agglomerated liquid 1 discharged from the continuous agglomerator (21a) is continuously supplied to the third mixer (51) having a capacity of 20 mL containing the anchor stirring blade (13c), and simultaneously to the third mixer (51). A 10% neogen SC aqueous solution was continuously supplied at a rate of 1.6 mL / min and mixed with the flocculent liquid 1. The residence time in the third mixer (51) was 34 seconds. The internal temperature of the third mixer (51) was 65 ° C., and the rotation speed of the stirring blade (13c) was 200 rpm.

(Process (3))
The liquid mixture 3 exiting from the third mixer (51) was continuously supplied at a rate of 36 mL / min to a continuous fuser (41) with a capacity of 2000 mL having a pipe structure (42) having an inner diameter of 10 mm. The residence time at the continuous fuser (41) is 55 minutes. The jacket temperature of the continuous fuser (41) was 95 ° C. The effluent from the continuous fuser (41) is the toner particle dispersion 1. The particle size of the toner particle dispersion 1 after flowing for 1 hour was measured with a Coulter counter. The volume average particle size was 7.5 μm, and the ratio of the volume average particle size to the number average particle size was 1.15. It was. The outflow rate of the toner particle dispersion was 36 mL / min.

(Filtering and drying process)
Thereafter, the obtained toner particle dispersion was cooled, filtered with a Kiriyama funnel, washed with water, and dried with hot air to obtain toner particles (1). The obtained toner particles (1) had a volume average particle diameter of 7.5 μm as measured by Coulter counter and an average circularity of 0.95. The measured values are shown in Table 2.

(Measurement of theoretical plate number)
In Example 1, during the execution of the step (1), due to the change in the amount of copper element (derived from the pigment) in the effluent from the continuous aggregator (21) depending on whether or not the pigment dispersion was added, the continuous aggregator ( 21) The number of tank rows was predicted. In the case of the pin type blade continuous aggregator (21a), the number of tank rows was 3.5.

Example 2
In the same operation method as in Example 1, the length of the continuous aggregator (21a) is simply changed to 1/4 of the length of the continuous agglomerator in Example 1, and the agglomerated liquid is contained in the continuous agglomerator (21a). Therefore, the supply speed of each component was changed to 1/4 of the supply speed of Example 1, and the length of the pipe of the continuous fuser was also changed to 1/4. The obtained toner had a volume average particle diameter of 7.8 μm and a ratio of the volume average particle diameter to the number average particle diameter of 1.20. The average circularity was 0.96. The measured values are shown in Table 2.

Example 3
In the same operation method as in Example 1, the stirring speed of the continuous fuser (41) was simply changed to ¼ of the stirring speed of the continuous aggregator (21a) in Example 1. The obtained toner particles had a volume average particle size of 7.9 μm and a ratio of the volume average particle size to the number average particle size of 1.18. The average circularity was 0.95. The measured values are shown in Table 2.

Example 4
In the same operation method as in Example 1, the stirring blade (25) of the continuous aggregator (21a) was simply changed from the pin type (26) a) stirring blade to the anchor type (26b) stirring blade. The obtained toner had a volume average particle size of 8.0 μm and a ratio of the volume average particle size to the number average particle size of 1.20. The average circularity was 0.95. By measuring the copper content of the pigment in the effluent from the continuous agglomerator (21a), the number of tank rows in the case of the continuous agglomerator (21b) with an anchor blade was 1.5. The measured values are shown in Table 2.

Table 1 shows the structure data and operation data of the continuous aggregator (21) used in Examples 1 to 4.

「粒度分布」は、体積平均粒径／個数平均粒径 の値である。

“Particle size distribution” is a value of volume average particle size / number average particle size.

  As apparent from Examples 1 to 4, according to the toner production method of the present invention, toner particles could be produced continuously and stably and efficiently. Furthermore, the volume average particle diameter was adjustable, the particle size distribution was sharp, and the average circularity was excellent.

  Furthermore, when Example 1 and Examples 2-4 are compared, when the coagulation tank length is longer (compared with Example 2), the rotation speed (stirring speed) of the stirring blade for aggregation is faster and the shearing speed is faster. In the case (compared to Example 3), in the case of a pin-type stirring blade having a large number of tank rows (compared to Example 4), a sharper particle size distribution could be obtained (Example 1).

  According to the method for producing a toner for developing an electrostatic charge image of the present invention, toner particles having a small particle size and a narrow particle size distribution can be obtained with high productivity. Etc. are widely used.

FIG. 3 is a block diagram illustrating an example of a method for producing an electrostatic charge image developing toner of the present invention. (A): Step (1) Mixing and dispersing step; (b): Step (2) Aggregation step; (c): Step (3) Fusing step It is a figure which shows an example of the container used for the process (2) aggregation process in the manufacturing method of the toner for electrostatic image development of this invention. (A): Container using pin type wings (used in Examples 1 to 3); (b): Container using anchor type wings (used in Example 4)

Explanation of symbols

11a 1st mixer 11b 2nd mixer 12a 1st mixer stirring apparatus 12b 2nd mixer stirring apparatus 13a 1st mixer stirring blade 13b 2nd mixer stirring blade 13c 3rd mixer stirring blade 21 Step (2) Container used for coagulation process (continuous coagulator)
21a Pin type blade continuous agglomerator 21b Anchor type blade continuous agglomerator 22a First stage temperature control unit 22b Second stage temperature control unit 22c Third stage temperature control unit 22d Fourth stage temperature control unit 23 Continuous agglomeration Concentrator supply port 24 Continuous agglomerator outlet 25 Continuous agglomerator stirring blade 26a Pin type blade pin 26b Anchor type blade anchor 27 Continuous agglomerator stirring blade shaft 28 Continuous agglomerator inner wall 29 Continuous Stirrer 41 of type coagulator Continuous fuser 42 Pipe structure 51 of continuous fuser Third mixer 52 Stirrer 53 of third mixer 53 Liquid feeding hose
54 Pump p Polymer primary particle dispersion d Colorant dispersion e Electrolyte solution s Surfactant m Mixed dispersion

Claims (21)

In the method for producing an electrostatic charge image developing toner for producing toner particles in an aqueous medium, at least the following steps (1), (2) and (3):
(1) Step of supplying a colorant and polymer primary particles to prepare a mixed dispersion
(2) supplying the mixed dispersion to form aggregated particles
(3) Supplying aggregated particles to form fused particles
A process for producing an electrostatic charge image developing toner , wherein in steps (1) to (3), at least the step (2) comprises a step of continuously supplying and a step of continuously extracting . The method for producing a toner for electrostatic charge development according to claim 1 , wherein in the step (2), aggregated particles are formed with a shearing force of a shear rate of 100 s ⁻¹ or more. In step (2), a complete mixing tank according to claim 1 or method of manufacturing a toner for electrostatic development according to claim 2 tanks number of columns in the column model using two or more containers. The method for producing a toner for electrostatic charge development according to claim 3 , wherein the container used in the step (2) is a mixer having a cylindrical stirring blade or a multi-cylindrical parallel type. Container used in step (2) is static according to claim 3 or claim 4 in which the ratio of the sectional area S2 of the cross-sectional area S1 and the stirring blade axis of the container satisfies (S1 / S2) ≦ 20 A method for producing a charge developing toner. The container used in the step (2) is such that the ratio of the diameter d1 of the equivalent circle having the same area as the liquid passage effective area (S1-S2) and the length L of the container is (d1 / L) ≦ 2. either manufacturing method of the electrostatic developing toner according to claim of claims 3 to 5 is intended to satisfy. At least one withdrawal of the container used in step (2), any static charge according to claim of claims 1 to 6 than the supply port to present at the lowest position is installed in the upper developing Of manufacturing toner. The inner surface of the container used in step (2) is substantially stainless and / or any of claims manufacturing method of the electrostatic developing toner according to claim of claims 1 to 7 is glass. Container used in step (2) is any one of the preceding manufacturing method of the electrostatic developing toner according to claim of at least two or more containers in which are connected in series claims 1 to 8. The method for producing a toner for developing an electrostatic charge image according to claim 9 , wherein the temperature in the container on the downstream side of the container used in the step (2) is equal to or higher than the temperature in the container on the upstream side. In step (3), any one of claims manufacturing method of the electrostatic developing toner according to the claims 1 to 10 by applying a temperature higher than the glass transition point of the polymer primary particles to form fused particles . In step (3), vessel temperature of withdrawal outlet is any one of the preceding manufacturing method of the electrostatic developing toner according to claim of claims 1 to 11 is equal to or higher than temperature inside the container supply port. In step (1), in the state of the coloring agent and / or an aqueous dispersion of the volume average particle diameter of the polymer primary particles was 3μm or less, of claims 1 to 12 for supplying a coloring agent and a polymer primary particles A method for producing a toner for electrostatic charge development according to any one of claims. In step (1), any one of the preceding manufacturing method of the electrostatic developing toner according to claim polymer according to claim 1 primary particles contain a seed polymerization particles seed wax to claim 13. In step (2), according to claim 1 or any of claims manufacturing method of the electrostatic developing toner according to the preceding claims 14 to supply two or more primary polymer particles. The method for producing a toner for electrostatic charge development according to claim 15 , wherein in step (2), two or more kinds of polymer primary particles are supplied from different supply ports. The method further comprises the step of supplying at least one selected from the group consisting of resin fine particles, a colorant, a wax, and a charge control agent to a dispersion of aggregated particles aggregated to a volume average particle diameter of 1 μm or more. The method for producing a toner for developing an electrostatic charge according to claim 16 . The method for producing a toner for developing an electrostatic charge according to any one of claims 1 to 17 , wherein an electrolyte is supplied in the step (1) and / or the step (2). The process temperature of the step (2) is 10 ° C. or less higher than the glass transition point of the polymer primary particles, and the process temperature of the step (3) is 10 ° C. or more higher than the glass transition point of the polymer primary particles. claim production method of the electrostatic developing toner according to certain claims 1 to 18. 20. The method for producing a toner for developing an electrostatic charge according to any one of claims 1 to 19 , for producing a toner having a volume average particle diameter of 3 to 8 [mu] m. Any one of the preceding manufacturing method of the electrostatic developing toner according to the section average circularity claims 1 to 20 for producing a toner of more than 0.9.

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