JP2009186572A - Method for manufacturing toner particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing toner, for efficiently manufacturing the toner having excellent image developability and a sharp grain size distribution of dispersed droplets in a granulation step of dispersing a polymerizable monomer composition in an aqueous dispersion medium to obtain dispersed droplets. <P>SOLUTION: The method includes the granulation step of dispersing a polymerizable monomer composition containing a polymerizable monomer and a colorant in an aqueous dispersion medium, wherein the granulation step is carried out stepwise by using a granulation apparatus having high shear force, including both of a first process section having a structure suitable for mixing the aqueous dispersion medium with the polymerizable monomer composition and a second process section suitable for adding high shear to the polymerizable monomer composition for granulation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a toner and a toner particle manufacturing method for developing an electrostatic image in an image forming method such as electrophotography, electrostatic printing, and magnetic recording. In particular, the present invention relates to a method for producing dry toner particles used in a fixing method in which an image formed with toner is heated and fixed on a recording material.

  Conventionally, as a toner for electrophotography, a so-called pulverized toner having a desired particle size by a fine pulverizer and a classifier is generally used after a colorant is melt-mixed and uniformly dispersed in a thermoplastic resin. Although this production method can produce a considerably excellent toner, there is a problem in that particles in a wide particle size range are easily formed when fine pulverization is performed at high speed, and it is difficult to make fine particles. In order to overcome the problems of the toner by the pulverization method, there has been proposed a method for producing a polymerized toner in which a polymerizable monomer (monomer) is dispersed in the form of droplets and polymerization is performed to directly obtain toner particles.

  For example, in the method for producing toner particles by the suspension polymerization method, a polymerizable monomer, a colorant, a release agent, a polymerization initiator and, if necessary, a crosslinking agent, a charge control agent and other additives are uniformly added. After dissolving or dispersing to form a polymerizable monomer composition, this is dispersed in an aqueous medium containing a dispersion stabilizer using an appropriate stirrer, and subjected to a polymerization reaction to obtain a desired particle size. A suspension of polymerized toner particles having If necessary, the suspension of the polymerized toner particles is treated with acid or alkali to remove the dispersion stabilizer, and then the aqueous medium is separated in a solid-liquid separation step to obtain toner particles.

  Since the polymer toner particles obtained by such a method do not include a pulverization step, the toner does not need to be brittle, a soft material can be used as a resin, and a colorant on the particle surface can be used. There is an advantage that a toner having no uniform exposure and triboelectric chargeability can be obtained. In addition, since the particle size distribution of the obtained toner is relatively sharp, even if the classification process is omitted or classified, the toner can be obtained in high yield, saving energy, shortening time, improving process yield, etc. The cost reduction effect is great. In addition, since a large amount of a low softening point substance can be encapsulated in the toner as a release agent, there is an advantage that the obtained toner has excellent offset resistance.

  Even when the suspension polymerization method is used, generation of fine particles and coarse particles having a certain undesirable particle size is inevitable. If the abundance of fine particles and coarse particles is large, it is not preferable from the viewpoint of toner properties and production efficiency as described above, and therefore it is necessary to make the particle size distribution during suspension polymerization as narrow as possible.

  Conventionally, when a polymerizable monomer composition containing at least a polymerizable monomer and a colorant is granulated in an aqueous dispersion medium containing a dispersion stabilizer, a method using a stirrer having a high shear force is used. Has been devised. For example, a method of stirring a dispersion using a turbine type stirrer has been devised (Patent Document 1). In addition to this, the dispersion is pressed against the side wall of the granulation tank by centrifugal force to form a liquid film, and the liquid film is granulated by touching the tip of a stirring blade that rotates at an ultrahigh speed (Patent Document 2). And a batch-type granulation method using a high-shearing stirrer equipped with a stirring blade rotating at high speed in a stirring tank and a screen surrounding the stirring blade (Patent Document 3). A relatively sharp particle size distribution can be obtained by granulating droplets using such an apparatus having a high granulation ability. In addition, as a method of performing in-line granulation, a method of performing granulation by a shearing force caused by passing through a gap between a rotor and a stator that are comb-shaped concentric rings has been devised (Patent Document 4). A relatively sharp particle size distribution can be obtained by granulating droplets using such a device with high granulation ability, but mixing of an aqueous dispersion medium and a polymerizable monomer composition immediately before granulation The state may not be uniform, and fine particles and / or coarse particles may be contained in the granulated droplets.

  In order to further sharpen the particle size distribution, granulate the polymerizable monomer composition and the aqueous dispersion medium through a static in-tube mixer and then granulate the particle size distribution using a stirrer with high shear force. A method of granulating with a plurality of apparatuses, such as a method of preparing (Patent Document 5) and a method of processing a processing liquid granulated with a high shearing force stirring apparatus with a high shearing force stirring apparatus (Patent Document 6) has also been devised. ing. However, since these methods use a plurality of devices, the capital investment is increased, which is not preferable in terms of production cost. In addition, the droplets dispersed by the first granulator unite the granulated droplets when they are transferred between the units, and coarse particles exist even after the processing by the second granulator unit. There's a problem.

  In recent years, the shift from analog to digital in printers and copiers has progressed, and it has been demanded that latent images have excellent reproducibility and high resolution. Therefore, further sharpening of the particle size distribution of toner particles is required. ing. The toner particles obtained by polymerization may contain fine and coarse particles that are out of the desired particle size range, and there is room for improvement.

Japanese Patent Publication No. 36-10231 Japanese Patent Publication No. 43-10799 Japanese Patent Publication No. 51-14895 JP-A-2-32363 JP-A-10-195205 JP 2006-065197 A

  An object of the present invention is to provide a method for producing toner particles that solves the above-described problems. That is, the present invention provides a method for producing toner particles having a sharp particle size distribution and excellent developability in a method for producing toner particles obtained by granulating a polymerizable monomer composition in an aqueous medium. This is the issue.

  As a result of intensive studies to solve the above problems, the present inventors include a granulation step of dispersing a polymerizable monomer composition containing at least a polymerizable monomer and a colorant in an aqueous dispersion medium. In the toner manufacturing method, the first processing unit includes two processing units, and the first processing unit includes a first rotor group in which rotors having gear-like protrusions are arranged in multiple stages in the rotation axis direction. Is coaxial with the first rotor group, and a plurality of protrusions are arranged in a circular shape with a minute gap around the rotation axis, and the circular protrusions are concentrically formed in multiple stages. The second rotor group, the same axis as the first rotor group, and a plurality of protrusions are arranged in a circular shape around the rotation axis with a minute gap, and the circular protrusions are concentric. So that the stator groups formed in multiple stages face each other and mesh with each other at a constant interval By using the granulating apparatus being location, size distribution sharp, found that it is possible to obtain an excellent toner particles on the developing property.

The features of the present invention are as follows.
(1) A method for producing a toner comprising a granulation step of dispersing a polymerizable monomer composition containing at least a polymerizable monomer and a colorant in an aqueous dispersion medium,
The granulating apparatus used in the granulating step has a two-stage configuration, and the first processing unit is composed of a first rotor group in which rotors having gear-like protrusions are arranged in multiple stages in the rotation axis direction. The two processing parts are coaxial with the first rotor group, and the protrusions are arranged so as to form a circle centered on the rotation axis with a minute gap, and the protrusions are concentrically formed in multiple stages. The two rotor groups are coaxial with the first rotor group, and the protrusions are arranged so as to form a circle around the rotation axis, and the protrusions are concentrically formed in multiple stages. A method for producing toner particles, wherein the stator group is alternately combined with the protrusions.
(2) After the mixture of the polymerizable monomer composition and the aqueous dispersion medium passes through the first rotor group in the direction of the second processing section, the second processing section is moved from the center of the concentric circle to the centrifugal direction. The method for producing toner particles according to (1), wherein the toner particles pass.
(3) Production of toner particles according to (1) or (2), wherein the peripheral speed S (m / s) of the outermost peripheral portion of the second rotor group is 45 ≦ S ≦ 90. Method.
(4) In the granulation step, the back pressure P (MPaG) in the granulator is 0.1 ≦ P ≦ 0.6, wherein any one of (1) to (3) The manufacturing method of the toner particle of description.
(5) The gap d (mm) between the projections of the outermost shell in the rotor group and the stator group of the second processing unit is 0.1 ≦ d ≦ 2.0 (1) The manufacturing method of the toner particle in any one of thru | or (4).
(6) The total length L (m) in the rotation axis direction combining the second processing unit from the first processing unit in the granulation apparatus, and the length l (m) between the first processing unit and the second processing unit The toner particle manufacturing method according to any one of (1) to (5), characterized in that 0.05 ≦ l / L ≦ 0.5.
(7) The method for producing toner particles according to any one of (1) to (6), wherein the polymerizable monomer composition has a viscosity of 400 mPa · s or less.

  According to the present invention, toner particles having a sharp particle size distribution and excellent developability can be produced.

  The present invention will be described in more detail with reference to preferred embodiments used in the present invention. FIG. 1 is an example of a schematic diagram of a granulation system incorporating a preferred granulation apparatus 1 used in the present invention. In FIG. 1, 1 is a granulator 1, 2 is a preliminary dispersion tank, 3 is a circulation pump, 4 is a stirring blade, and 5 is a motor.

  As a method for forming toner particles, there are a method using suspension polymerization and a solution suspension method. Suspension polymerization is a polymerization method in which polymerization proceeds in oil droplets of monomers dispersed in water. A dispersion stabilizer is used to prevent coalescence of oil droplets. A polymerization initiator that is soluble in the monomer is used. The dissolution suspension method is a method of obtaining resin fine particles by dispersing a resin composition containing a resin dissolved in an organic solvent in an aqueous dispersion medium and then removing the organic solvent.

  The present invention relates to toner particles using a solution suspension method or suspension polymerization in which fine particles are produced by dispersing a polymerizable monomer composition containing at least a polymerizable monomer and a colorant in an aqueous medium. Applicable to manufacturing method.

  The method for producing the toner of the present invention by the suspension polymerization method will be described below.

(Colorant dispersion process)
A polymerizable monomer composition in which a colorant is uniformly dissolved and / or dispersed in a polymerizable monomer by a stirrer, a homogenizer, an ultrasonic disperser or the like that is usually used is used. Moreover, a mold release agent, a charge control agent, etc. can also be added as needed.

  A magnetic material can be used in the toner particle manufacturing method. Hereinafter, magnetic materials that can be suitably used will be described. First, the magnetic surface is hydrophilic and the polymerizable monomer is hydrophobic. For this reason, if the hydrophobic treatment on the surface of the magnetic material is not uniform, good dispersibility of the magnetic material cannot be obtained. Further, even if the magnetic material is physically dispersed (such as mechanically or by ultrasonic dispersion), the magnetic material with non-uniform surface treatment is aggregated again and the Stokes diameter becomes large. Secondly, even if the treatment is uniform, the dispersion of the magnetic material is inferior if the polymerizable monomer that is the dispersion medium is not compatible with the magnetic material. Therefore, in the magnetic material used in the magnetic toner of the present invention, when the particle surface is hydrophobized, the coupling agent is hydrolyzed while dispersing the magnetic material particles in the aqueous medium so as to have a primary particle size. However, it is very preferable to use a surface treatment method. This hydrophobic treatment method is less likely to cause coalescence between the magnetic particles than the treatment in the gas phase, and the repulsive action between the magnetic particles due to the hydrophobic treatment works, so that the magnetic material is almost in the state of primary particles. Surface treated.

  The method of treating the surface of the magnetic material while hydrolyzing the coupling agent in an aqueous medium does not require the use of a coupling agent that generates a gas, such as chlorosilanes and silazanes, and further, In the phase, magnetic particles can be easily combined with each other, and a highly viscous coupling agent that has been difficult to be processed can be used, so that the hydrophobizing effect is great.

  Examples of the coupling agent that can be used in the surface treatment of the magnetic material according to the present invention include a silane coupling agent and a titanium coupling agent. More preferably used is a silane coupling agent, and the magnetic material obtained in this way has no aggregation of particles, and since the surface of each particle is uniformly hydrophobized, the Stokes diameter becomes small and the magnetic material is magnetic. The dispersibility of the body is good.

(Aqueous dispersion medium preparation process and granulation process)
An aqueous dispersion medium containing a dispersion stabilizer is prepared. The aqueous dispersion medium and the polymerizable monomer composition are supplied to the granulator at a constant ratio. The method for supplying the aqueous dispersion medium and the polymerizable monomer composition is not particularly limited, and each may be supplied individually. Alternatively, a premixed aqueous dispersion medium and a polymerizable monomer composition may be supplied. In order to sharpen the particle size of the dispersed droplets, it is necessary to generate droplets by applying a high shearing force to the mixed solution of the uniformly dispersed aqueous dispersion medium and the polymerizable monomer composition.

  As a result of intensive studies by the present inventors, in order to obtain toner particles having a sharp particle size distribution and excellent developability, at least a polymerizable monomer and a polymerizable monomer composition containing a colorant are dispersed in an aqueous system. The granulation process for dispersion in a medium is performed by first applying a high shear to the first treatment part having a structure suitable for mixing the aqueous dispersion medium and the polymerizable monomer composition. It has been found that it is desirable to perform granulation step by step using a high shearing granulator having a second treatment section suitable for granulation.

  A granulating apparatus having a two-stage configuration of a first processing unit and a second processing unit preferably used in the present invention will be described. However, the granulating apparatus used in the present invention is not limited to this.

  The figure which shows a granulation apparatus is FIG. 2 thru | or FIG. FIG. 2 shows a granulating apparatus 1, 6 is an inner wall of the first processing section, 7 is a supply port for an aqueous dispersion medium and a polymerizable monomer composition, 8 is a first processing section, 9 is a rotating shaft, The second processing unit, 11 is a motor, and 12 is an outlet for processing liquid processed by the granulating apparatus. FIG. 3 shows the first processing unit and the second processing unit in FIG. 2, 9 is a rotating shaft, 10 is a second processing unit, and 13 is a gear-like projection of the first processing unit. FIG. 4 is a perspective view of the second rotor group of the second processing unit, wherein 14 is a rotor, 15 is a protrusion of the second rotor group, and 16 is a gap between the protrusions of the second rotor group. To express. FIG. 5 is a perspective view of the stator group of the second processing unit, where 17 is a stator, 18 is a protrusion of the stator group, and 19 is a gap between the protrusions of the stator group. 6 is a cross-sectional view taken along the line AA 'of FIG.

  In the first processing unit of the granulating apparatus, gear-shaped protrusions are arranged in multiple stages in the direction of the rotation axis. As the polymerizable monomer composition and the aqueous dispersion medium pass through the first treatment section, the polymerizable monomer composition and the aqueous dispersion medium are mixed and predispersed. The second processing unit has a second rotor group in which the rotors arranged concentrically so that the projections have a minute gap are arranged in multiple stages, and the projections so as to have a minute gap concentrically. The arranged stator is composed of a stator group arranged in multiple stages. The second rotor group and the stator group are arranged such that the protrusions are alternately combined. When the polymerizable monomer composition and the aqueous dispersion medium pass through the second processing section, the second rotor group, impact due to compression / discharge in the centrifugal direction due to the displacement of the slits of the stator group, The polymerizable monomer composition is granulated by the impact caused by the shear between the rotor group and the stator group, and sharp droplets are formed.

  In the granulating apparatus of the present invention, the dispersion of the polymerizable monomer composition that has been uniformly predispersed in the first processing section is immediately sent to the second processing section in the same apparatus and finely dispersed. By performing preliminary dispersion in the first processing section, preliminary dispersion processing is performed in which the ratio of the polymerizable monomer composition and the aqueous dispersion medium per unit volume is uniform. As a result, the impact applied to the polymerizable monomer composition in the second processing portion becomes uniform, so that droplets of the polymerizable monomer composition having a sharp particle size distribution are formed.

  When the granulation step is performed using an apparatus that performs preliminary dispersion and an apparatus that performs fine dispersion, it is necessary to transfer the treatment liquid that has been subjected to preliminary dispersion to the granulation apparatus. Since the pre-dispersed droplets of the pre-dispersed polymerizable monomer composition are united during this transfer, the impact applied to the polymerizable monomer composition by the granulator is not uniform. The formed droplet sizes are not uniform and the particle size distribution is broadened.

  After the polymerizable monomer composition and the aqueous dispersion medium have passed through the first processing section in the direction of the second processing section, the protrusions of the second rotor group and the stator group are concentrically arranged in multiple stages and alternately. Passing through the second processing portion arranged in the centrifuge from the inside of the protrusion in the centrifugal direction is preferable because a large amount of shearing and impact can be applied and the granulation efficiency can be increased.

  It is preferable that the peripheral speed S (m / s) of the outermost peripheral part of the second rotor group of the granulating apparatus in the present invention is in a range of 45 ≦ S ≦ 90. If it is within this range, the compression of the polymerizable monomer composition caused by the displacement of the slit between the second rotor group and the stator group in the centrifugal direction, impact due to discharge, and the second rotor group are fixed. Impact due to shear between the subgroups can be sufficiently applied to the polymerizable monomer composition, and droplets having a sharp particle size distribution can be formed.

  When the peripheral speed is less than 45 m / s, impact due to compression and discharge in the centrifugal direction in the second processing unit and impact due to shear between the second rotor group and the stator group are reduced. Further, the uniformity of the preliminary dispersion by the first rotor group of the first processing unit rotating coaxially is also lowered. As a result, the mixed state of the polymerizable monomer and the aqueous dispersion medium becomes non-uniform, and the impact applied in the second processing section is not uniform, so that the particle size distribution of the formed droplets is not uniform.

  When the peripheral speed exceeds 90 m / s, many very fine particles that are not suitable for use as a toner are generated, and the particle size distribution becomes wide.

  Further, the back pressure P (MPaG) in the granulator may be in the range of 0.1 ≦ P ≦ 0.5. By adjusting the inflow amounts of the polymerizable monomer composition and the aqueous dispersion medium so as to be within this range, it is possible to secure a residence time necessary for preliminary dispersion in the first processing section. Furthermore, the impact due to compression and discharge in the second processing unit can be increased, which is preferable.

  When the back pressure is smaller than 0.1 MPaG, the flow rate is difficult to stabilize. Further, it is not preferable because the residence time in the first processing section cannot be secured and a short pass occurs and uniform processing cannot be performed. When the back pressure is larger than 0.5 MPaG, the pressure fluctuation received by the treated droplets becomes large and the coalescence of the droplets is likely to occur, which is not preferable. Since resistance to rotation of the first rotor group and the second rotor group is increased, the motor is enlarged and the capital investment is increased, which is not preferable.

  The total length L (m) in the direction of the rotation axis in which the second processing unit is combined from the first processing unit in the granulation apparatus and the length l (m) between the first processing unit and the second processing unit are 0.05 ≦. It is preferable to satisfy the relationship of 1 / L ≦ 0.5. If it is within this range, the ratio of the polymerizable monomer composition per unit volume is kept uniform with almost no coalescing of polymerizable monomer droplets preliminarily dispersed in the first processing section. Since it introduce | transduces into a process part, the shearing and impact to the polymerizable monomer composition in a 2nd process part become uniform, and it is preferable from a viewpoint of sharpening of a particle size distribution.

  When 1 / L is smaller than 0.05, the flow of the polymerizable monomer composition and the aqueous dispersion medium from the first processing section to the second processing section is hindered, and the flow rate becomes difficult to stabilize, which is not preferable. When l / L is greater than 0.5, the preliminarily dispersed polymerizable monomer is transferred when the polymerizable monomer composition and the aqueous dispersion medium are transferred between the first processing section and the second processing section. This is not preferable because the body composition is united and the uniformity of the polymerizable monomer composition contained per unit volume is lost.

  The gap d (mm) between the projections of the outermost shell in the rotor group and the stator group of the second processing unit is preferably in the range of 0.1 ≦ d ≦ 2.0. If it is in this range, sufficient discharge can be performed from the gap between the protrusions of the rotor and the stator.

  When the gap width is smaller than 0.1 mm, a large pressure loss occurs at the time of discharge, and it is not preferable because it is difficult to secure a sufficient flow rate. When the gap width is larger than 2.0 mm, the impact due to compression / discharge in the centrifugal direction is reduced, so that a sufficient granulation effect cannot be obtained.

  Further, it is preferable that the gap between the protrusions becomes narrower as it goes toward the outer periphery on the concentric circle, or the gap width between the inner and outer protrusions is equal.

  The viscosity of the polymerizable monomer composition is preferably 400 mPa · s or less. If it is 400 mPa · s or less, preliminary dispersion in the first processing section and granulation in the second processing section proceed well. When it is larger than 400 mPa · s, the preliminary dispersion in the first processing unit is not sufficiently performed. Furthermore, droplet formation due to impact and shear in the second processing section is not sufficient, and coarse particles are generated, or particles smaller than the desired particle size are generated at the same time as droplet formation, so the particle size distribution is broad. become. Further, the load on the first and second rotors is increased, which is not preferable because the motor is enlarged and the capital investment is increased.

  It is preferable that the gap between adjacent protrusions of the gear-shaped rotor formed by the protrusions of the first rotor group arranged in multiple stages becomes narrower as it is arranged on the second processing unit side. By arranging the rotor in this way, the treatment liquid is sufficiently retained and dispersion is performed well.

  Examples of the granulating apparatus including the first processing unit and the second processing unit preferably used in the present invention include a sharp flow mill (manufactured by Taiheiyo Kiko Co., Ltd.), but are not limited thereto.

(Polymerization process)
In the polymerization step in the present invention, a general stirring tank capable of adjusting the temperature can be used. The polymerization temperature is 40 ° C or higher, generally 50 to 90 ° C. The polymerization temperature may be constant throughout, but may be raised in the latter half of the polymerization step for the purpose of obtaining a desired molecular weight distribution.

(Purification process)
(Solid-liquid separation process, washing process and drying process)
In order to remove volatile impurities such as unreacted monomers and by-products, a part of the aqueous dispersion medium may be distilled off after completion of the polymerization. Distillation can be performed under normal pressure or reduced pressure. In order to remove the dispersion stabilizer attached to the surface of the polymer fine particles obtained by polymerizing the dispersed droplets, the polymer fine particle dispersion can be treated with an acid or an alkali. Thereafter, the polymer fine particles are separated from the liquid phase by a general solid-liquid separation method. However, in order to completely remove the acid or alkali and the dispersion stabilizer component dissolved therein, water is added again to remove the polymer fine particles. Wash. This washing process is repeated several times, and after sufficient washing, solid-liquid separation is performed again to obtain toner particles. The obtained toner particles are dried by a known drying means if necessary. Although heat can be applied as a drying means, usually a large amount of heat applied to the toner particles can affect the developability because the release agent and low molecular weight components contained in the toner particles are exposed. is there. However, the toner particles according to the present invention have a sharp molecular weight distribution and a small amount of low molecular weight components. Therefore, if the drying temperature is 110 ° C. or less, the developability of the toner particles is not affected.

(Classification process)
The toner particles obtained in this way have a sufficiently sharp particle size as compared with conventional pulverized toners, but if a sharper particle size is required, classification can be performed by an air classifier or the like. It is also possible to remove particles that deviate from the particle size distribution as predetermined external particles.

  As the material of each member constituting the apparatus used in each of the above-described processes, a commonly used material such as stainless steel, glass, FRP, ceramic can be used. In addition, these surfaces may be subjected to treatments such as electrolytic polishing, fluororesin coating, and glass lining. The toner obtained by the production method of the present invention may be composed only of toner particles obtained by the polymerization method described above, or obtained by externally adding other additives to the toner particles as necessary. It may be. The toner particles and carrier may be mixed to form a two-component toner.

[monomer]
As a monomer suitably used in the present invention, a vinyl polymerizable monomer capable of radical polymerization is used. As the vinyl monomer, a monofunctional monomer or a polyfunctional monomer can be used.

  Monofunctional monomers include styrene, α-methyl styrene, β-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, 2,4-dimethyl styrene, pn-butyl styrene, p-tert. -Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene, etc. Styrene derivatives; methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n Acrylic monomers such as octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate; methyl methacrylate, ethyl methacrylate N-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate , Diethyl phosphate ethyl methacrylate Methacrylic monomers such as dibutyl phosphate ethyl methacrylate; vinyl esters such as methylene aliphatic monocarboxylic acid ester, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl formate; vinyl methyl ether, vinyl ethyl ether, And vinyl ethers such as vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropyl ketone.

  As polyfunctional monomers, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, polypropylene Glycol diacrylate, 2,2′-bis (4- (acryloxydiethoxy) phenyl) propane, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, Tetraethylene glycol dimethacrylate, polyethylene glycol dimethyl Chlorate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2′-bis (4- (methacryloxydiethoxy) phenyl) propane, 2,2′-bis (4- (methacryloxypolyethoxy) phenyl) propane, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, divinylbenzene, divinylnaphthalene, divinyl ether and the like can be mentioned.

  In the present invention, the above monofunctional monomers are used singly or in combination of two or more, or the above monofunctional monomers and polyfunctional monomers are used in combination. Among the above-described monomers, styrene or a styrene derivative is preferably used alone or in combination, or in combination with other monomers from the viewpoint of toner development characteristics and durability.

[Colorant]
Examples of the colorant used in the present invention include carbon black, iron black, C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Dyes such as Basic Green 6, yellow lead, cadmium yellow, mineral fast yellow, navel yellow, naphthol yellow S, Hansa yellow G, permanent yellow NCG, tartrazine lake, molybdenum orange, permanent orange GTR, benzidine orange G, cadmium red, Permanent Red 4R, Watching Red Calcium Salt, Brilliant Carmine 3B, Fast Violet B, Methyl Violet Lake, Bitumen, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Quinacridone, Rhodamine Lake, Phthalocyanine Blue, Fast Sky Blue, Pigment Green B, Examples of the pigment include malachite green lake and final yellow green G.

  In selecting a colorant, it is necessary to pay attention to the polymerization inhibitory property and water phase transferability of the colorant. In particular, since dyes and carbon black often have polymerization inhibiting properties, care must be taken when using them. Preferably, these should be subjected to surface modification, for example, a hydrophobic treatment with a substance that does not inhibit polymerization. Examples of the method for surface-treating the dye include a method in which a polymerizable monomer is polymerized in the presence of these dyes in advance, and the obtained colored polymer is added to the polymerizable monomer composition. In addition to carbon black, the carbon black may be grafted with a substance that reacts with the surface functional groups of the carbon black, such as polyorganosiloxane.

[Release agent]
As the release agent used in the present invention, a wax in a solid state at room temperature may be used in terms of toner blocking resistance, multi-sheet durability, low-temperature fixability, and offset resistance.

  Examples of the wax include polymethylene wax such as paraffin wax, polyolefin wax, microcrystalline wax, and Fischer-Tropsch wax, amide wax, higher fatty acid, long chain alcohol, ester wax, and derivatives such as graft compounds and block compounds. These are preferably removed from the low molecular weight component and have a sharp maximum endothermic peak in the endothermic curve obtained by a differential scanning calorimeter. In order to improve the translucency of the image fixed on the OHP, a linear ester wax is particularly preferably used. The linear ester wax may be contained in an amount of 1 to 40 parts by weight, more preferably 4 to 30 parts by weight, based on 100 parts by weight of the monomer.

  In the present invention, a second release agent having a melting point lower than 80 ° C. can be used in combination in order to increase the plasticity of the toner particles and improve the fixability in the low temperature region. As the second release agent, a linear alkyl alcohol having 15 to 100 carbon atoms, a linear fatty acid, a linear acid amide, a linear ester or a montan derivative wax is preferably used. It is more preferable that impurities such as liquid fatty acid have been previously removed from these waxes.

[Charge control agent]
The toner produced according to the present invention may contain a charge control agent. Known charge control agents can be used. For example, organic metal compounds and chelate compounds are effective for controlling the toner to be negatively charged, and monoazo dye metal compounds, acetylacetone metal compounds, aromatic hydroxy compounds. Examples include carboxylic acids, aromatic mono- and polycarboxylic acids and metal salts thereof, anhydrides, esters, and phenol derivatives such as bisphenol. Urea derivatives, metal-containing salicylic acid compounds, quaternary ammonium salts, calixarene, silicon compounds, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-acrylic-sulfonic acid copolymers, non-metals Examples thereof include carboxylic acid compounds.

  Examples of toners that are controlled to be positively charged include modified products of nigrosine and fatty acid metal salts, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, And onium salts such as phosphonium salts which are analogs thereof, and lake pigments thereof, triphenylmethane dyes and lake lake pigments (the rake agents include phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid , Lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.), metal salts of higher fatty acids, diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide, dibutyltin borate Dioctyl tin borate, include diorgano tin borate such as dicyclohexyl tin borate, may be used in combination alone, or two or more kinds. Among these, a charge control agent such as a nigrosine-based quaternary ammonium salt is particularly preferably used.

  These charge control agents are used in an amount of 0.01 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the monomer.

[Polymerization initiator]
Examples of the polymerization initiator that can be used in the present invention include azo polymerization initiators. As azo polymerization initiators, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile) 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobismethylbutyronitrile, and the like.

  An organic peroxide initiator can also be used. Organic peroxide initiators include benzoyl peroxide, lauroyl peroxide, di-α-cumyl peroxide, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, bis (4-t-butyl) (Cyclohexyl) peroxydicarbonate, 1,1-bis (t-butylperoxy) cyclododecane, t-butylperoxymaleic acid, bis (t-butylperoxy) isophthalate, methyl ethyl ketone peroxide, tert-butylperoxy Examples include 2-ethylhexanoate, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, and the like.

  A redox initiator in which an oxidizing substance and a reducing substance are combined can also be used. Examples of the oxidizing substance include inorganic peroxides such as hydrogen peroxide and persulfates (sodium salts, potassium salts, ammonium salts, etc.), and oxidizing metal salts such as tetravalent cerium salts. Reducing substances include reducing metal salts (divalent iron salts, monovalent copper salts, trivalent chromium salts, etc.), ammonia, and lower amines (amines having about 1 to 6 carbon atoms such as methylamine and ethylamine). Amino compounds such as hydroxylamine, sodium thiosulfate, sodium hydrosulfite, sodium hydrogen sulfite, sodium sulfite, sodium formaldehyde sulfoxylate and other reducing sulfur compounds, lower alcohols (about 1 to 6 carbon atoms), ascorbic acid or Examples thereof include salts thereof and lower aldehydes (having about 1 to 6 carbon atoms). The initiator is selected with reference to the 10-hour half-life temperature, and is used alone or in combination. The addition amount of the polymerization initiator varies depending on the desired degree of polymerization, but generally 0.5 to 20 parts by mass is added to 100 parts by mass of the monomer.

[Crosslinking agent]
Various cross-linking agents can also be used in the present invention. Examples of the crosslinking agent include divinylbenzene, 4,4′-divinylbiphenyl, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, glycidyl (meth) acrylate, and trimethylolpropane tri (meth) acrylate. Mention may be made of functional compounds.

[Distributed media]
The dispersion medium may be any known medium used in various polymerization methods, and is appropriately selected depending on the monomer used, the polymerization method, and the like, and is not particularly limited. In suspension polymerization, an aqueous medium is used.

[Dispersion stabilizer]
As a dispersion stabilizer for satisfactorily dispersing toner raw materials in an aqueous medium, for example, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, which are inorganic compounds , Magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, titania and the like. Examples of the organic compound include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, starch and the like. The dispersion stabilizer is preferably used in an amount of 0.2 to 10.0 parts by mass with respect to 100 parts by mass of the monomer.

  Commercially available dispersion stabilizers may be used as they are, but when using the above-mentioned inorganic compound, in order to obtain dispersed particles having a fine uniform particle size, the inorganic compound is generated under stirring in a dispersion medium. You can also. For example, in the case of tricalcium phosphate, a dispersion stabilizer suitable for the suspension polymerization method can be obtained by introducing and mixing an aqueous sodium phosphate solution and an aqueous calcium chloride solution into sufficiently stirred water.

[Polar resin]
In the case of a polymerization method using an aqueous medium such as suspension polymerization, the inclusion of a release agent can be promoted by adding a polar resin to the toner raw material. When a polar resin is present in the toner raw material suspended in an aqueous medium, the polar resin tends to move near the interface between the aqueous medium and the toner raw material due to the difference in affinity for water, so the polar resin is unevenly distributed on the toner surface. Will do. As a result, the toner particles have a core-shell structure, and the inclusion property of the release agent is improved even when a large amount of the release agent is contained.

  As such a polar resin, a saturated or unsaturated polyester resin is particularly preferable because the fluidity of the polar resin itself can be expected when it is unevenly distributed on the toner surface to form a shell.

  As the polyester-based resin, those obtained by condensation polymerization of the following acid component monomers and alcohol component monomers can be used. Acid component monomers include terephthalic acid, isophthalic acid, phthalic acid, fumaric acid, maleic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, camphoric acid , Cyclohexanedicarboxylic acid, trimellitic acid and the like. As alcohol component monomers, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-bis (hydroxymethyl) Examples include alkylene glycols such as cyclohexane and polyalkylene glycols, bisphenol A, hydrogenated bisphenol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, glycerin, trimethylolpropane, pentaerythritol, and the like.

[External additive]
In the production method of the present invention, an external additive can be used for the purpose of imparting various properties to the toner. The external additive preferably has a particle size of 1/10 or less of the average particle size of the toner particles from the viewpoint of durability when added to the toner. Examples of external additives include metal oxides such as aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide, and zinc oxide, nitrides such as silicon nitride, and carbides such as carbide silicon carbide. Inorganic metal salts such as calcium sulfate, barium sulfate and calcium carbonate, fatty acid metal salts such as zinc stearate and calcium stearate, carbon black, silica and the like are used.

  These external additives are used in an amount of 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, based on 100 parts by weight of toner particles. The external additives may be used singly or in combination of two or more, but those subjected to hydrophobic treatment are more preferable. Furthermore, the production method of the present invention can also be applied to a production method of a magnetic toner containing a magnetic material.

[Magnetic material]
The magnetic material contained in the toner can also serve as a colorant. In the present invention, the magnetic material contained in the magnetic toner includes iron oxides such as magnetite, hematite and ferrite, metals such as iron, cobalt and nickel, or these metals and aluminum, cobalt, copper, lead, magnesium, tin, Examples thereof include alloys of metals such as zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof.

These magnetic materials have an average particle diameter of 2 μm or less, preferably about 0.1 to 0.5 μm. The content of the magnetic substance in the toner is about 20 to 200 parts by mass, particularly preferably 40 to 150 parts by mass with respect to 100 parts by mass of the monomer. In addition, the magnetic properties of the magnetic material when 800 kA / m is applied are as follows: coercive force (Hc) 1.6 to 24 kA / m, saturation magnetization (σs) 50 to 200 Am ² / kg, residual magnetization (σr) 2 to 20 Am ^2. / Kg is preferred.

[Hydrophobic agent]
In order to improve the dispersibility of these magnetic materials in the toner particles, it is also preferable to subject the surface of the magnetic material to a hydrophobic treatment. For the hydrophobization treatment, coupling agents such as a silane coupling agent and a titanium coupling agent are used. Among them, a silane coupling agent is preferably used, and the general formula RmSiYn is used.
[Wherein, R represents an alkoxy group, m represents an integer of 1 to 3, Y represents a hydrocarbon group such as an alkyl group, a vinyl group, a glycidoxy group or a methacryl group, and n represents an integer of 1 to 3] Show. ]
It is shown by. For example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (βmethoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyl Diethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxy Silane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, n-butyltrimethoxysilane, isobutyl Le trimethoxysilane, trimethyl methoxysilane, hydroxypropyl Ritori silane, n- hexadecyl trimethoxy silane, can be mentioned n- octadecyl trimethoxysilane.

  The toner according to the present invention has a finer particle diameter, more specifically, a weight average diameter of 4 measured by a Coulter counter in order to faithfully reproduce finer latent image dots in response to a demand for higher image quality. A toner having a coefficient of variation in number of 10 to 10 μm and 25% or less is most preferable. When the toner is less than 4 μm, a large amount of untransferred toner is generated on the photosensitive member or the intermediate transfer member due to poor transfer efficiency, which causes undesirable unevenness of the image due to fogging or transfer failure. Further, when the weight average diameter of the toner exceeds 10 μm, fusion to the member is likely to occur. When the number variation coefficient of the toner exceeds 25%, these tendencies become stronger and become a problem.

  In order to reduce the toner adhesion to the non-image area on the electrostatic image bearing member and the amount of residual toner, it is necessary that the chargeability of the toner particles is sufficient and uniform. Furthermore, when using a toner having a small particle diameter from the viewpoint of improving the image quality, the adhesion force of the toner particles increases, so the shape of the toner particles has a great influence on the toner adhesion to the non-image area on the electrostatic charge image carrier. Effect. In other words, the closer the toner particles are to a spherical shape and the more uniform the shape, the smaller the adhesion area of the particles, the less toner adhesion to the non-image area on the electrostatic image bearing member and the remaining amount of transfer residual toner, high image quality and durability Stability is possible.

  The toner produced according to the present invention can be used as either a one-component or two-component developer.

  In the case of a magnetic toner containing a magnetic material in the toner as a one-component developer, a method of transporting or charging the magnetic toner using a magnet built in the developing sleeve is used. Further, when non-magnetic toner containing no magnetic material is used, there is a method in which a blade and a fur brush are used to forcibly charge by a developing sleeve and the toner is attached to the sleeve to be conveyed.

  When the toner obtained by the production method of the present invention is used as a two-component developer, a carrier is used with the toner as a developer. Although it does not specifically limit as a carrier used for this invention, It is comprised by the single or composite ferrite state which mainly consists of iron, copper, zinc, nickel, cobalt, manganese, and a chromium atom.

  The average particle size of these carriers is preferably 10 to 100 μm, more preferably 20 to 50 μm.

  When the two-component developer is prepared, the mixing ratio between the carrier and the toner in the present invention is usually 2 to 15% by weight, preferably 4 to 13% by weight as the toner concentration in the developer. Is obtained. If the toner concentration is less than 2% by mass, the image density is low and impractical, and if it exceeds 15% by mass, fogging and in-machine scattering increase, resulting in image deterioration and increased developer consumption.

  EXAMPLES Hereinafter, although an Example, a comparative example, and a reference example are given and this invention is demonstrated more concretely, this invention is not limited at all by these. In the examples, the following method was used to measure the particle size distribution of the toner.

(1) Measurement of weight average particle diameter (D4) of toner The average particle diameter and particle size distribution of toner particles can be measured by various methods such as Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter Co.). In the present invention, a Coulter Multisizer (manufactured by Coulter Inc.) is connected to an interface (manufactured by Nikka) and a PC9801 personal computer (manufactured by NEC) which outputs the number distribution and volume distribution. Use to prepare 1% NaCl aqueous solution. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 to 5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolyte solution in which the sample is suspended is dispersed for about 1 to 3 minutes with an ultrasonic disperser, and the volume distribution is measured by measuring the volume and number of toner particles of 2 μm or more using the 100 μm aperture as the aperture by the Coulter Multisizer. And the number distribution were calculated.

  Then, the volume-based weight average particle diameter obtained from the volume distribution according to the present invention (D4: the median value of each channel is a representative value of the channel) and the number-based length average particle diameter obtained from the number distribution (D1). ) And the number variation coefficient.

(2) Number variation coefficient The number variation coefficient is
Number variation coefficient = number standard deviation / number average particle diameter × 100
Indicated by That is, the smaller the coefficient of variation, the sharper the particle size distribution of the toner particles, and a larger value indicates a broader particle size distribution.

(3) Dissolved oxygen concentration S for the saturated dissolved oxygen concentration S ₀ of dissolved oxygen concentration S / saturated dissolved oxygen concentration S measured colorant-containing polymerizable monomer composition _0, dissolved oxygen meter SG6 (Mettler-Toledo, Inc. ). The colorant-containing polymerizable monomer composition was heated to 60 ° C., and the inside of the container was purged with oxygen and stirred for 5 minutes. A dissolved oxygen sensor was placed in the colorant-containing polymerizable monomer composition, and the dissolved oxygen concentration measured at this time was defined as a saturated dissolved oxygen concentration S ₀ . The dissolved oxygen concentration S of the colorant-containing polymerizable monomer composition obtained by the dissolving step was measured by the same method as described above. From the measured saturated dissolved oxygen concentration S ₀ and the dissolved oxygen concentration S, the dissolved oxygen concentration S / saturated dissolved oxygen concentration S ₀ was determined.

(4) Viscosity measurement of polymerizable monomer composition Viscosity measurement of the polymerizable monomer composition was carried out using a rotational viscometer viscotester VT550 type (manufactured by Harke). A circulating thermostat DC5-K20 was connected to a Viscotester VT550 type (manufactured by Harke), and the measurement temperature was set to 60 ° C. As a measuring method, 7 cm ³ of the colorant-containing polymerizable monomer composition was put in an NV cup (manufactured by Harke), and an NV rotor (manufactured by Harke) was further added. The viscosity was measured from the shear stress when the shear rate was 1.0 × 10 ³ (s ⁻¹ ) in the CR mode.

(5) Evaluation of granulation property For the granulation property in the granulation step, a part of the slurry after polymerization is sampled, further washed and dried, and the number variation coefficient measured by the Coulter Multisizer is calculated and used as an index. did.

(6) Evaluation Method of Image Density of Toner Particles To 100 parts by mass of toner particles obtained after drying, 3 parts by mass of hydrophobic silica having a specific surface area of 200 m ² / g by BET method was externally added to obtain a toner. . A Canon LBP-2040 was used as an image forming apparatus, and 100 g of the obtained toner was filled in the cartridge. At room temperature and normal humidity (24 ° C / 60% RH), after running idle for 2 hours as an accelerated test for toner deterioration, print out up to 1000 images with a print rate of 2%. Solid image density was evaluated.

The obtained image was measured for reflection density using an SPI filter of Macbeth RD918 type.
A: Very good (density value 1.4 or higher)
B: Good (density value 1.2 or more and less than 1.4)
C: Normal (concentration value 1.0 or more and less than 1.2) (no problem in product)
D: Poor (density value less than 1.0)

(7) Fog Evaluation Method To 100 parts by mass of the toner particles obtained after drying, 3 parts by mass of hydrophobic silica having a specific surface area by the BET method of 200 m ² / g was externally added to obtain a toner. A Canon LBP-2040 was used as an image forming apparatus, and 100 g of the obtained toner was filled in the cartridge. Under normal temperature and humidity (24 ° C / 60% RH), after running idle for 2 hours as an accelerated test of toner deterioration, an image print test of 1000 sheets was performed with an image pattern consisting only of horizontal lines with a printing rate of 2%. The fog of the non-image area was measured. The fog was measured using a REFECTMETER MODEL TC-6DS manufactured by Tokyo Denshoku. The filter used was a green filter, and fog was calculated from the following formula.
Fog (reflectance) (%) = reflectance on standard paper (%) − reflectance of sample non-image area (%)

The criteria for fogging are as follows.
A: Very good (less than 1.5%)
B: Good (1.5% or more to less than 2.5%)
C: Normal (2.5% or more to less than 4.0%) (No problem in product)
D: Poor (4.0% or more)

<Example 1>
A circulation system incorporating the granulating apparatus 1 shown in FIG. 1 was used. In the pre-dispersion tank 2, 850 parts by mass of a 0.1 mol / liter Na ₃ PO ₄ aqueous solution was added to 710 parts by mass of ion-exchanged water, and the mixture was stirred while stirring at 110 rpm using a full zone blade (Shinko Pantech Co., Ltd.). Held at 0C. To this, 68 parts by mass of a 1.0 mol / liter-CaCl ₂ aqueous solution was gradually added to prepare an aqueous dispersion medium containing a fine hardly water-soluble dispersion stabilizer Ca ₃ (PO ₄ ) ₂ .

Styrene monomer 170 parts by mass Carbon black 40 parts by mass E-88 (manufactured by Orient Chemical Co., Ltd.) 2 parts by mass T-77 (manufactured by Hodogaya Chemical Co., Ltd.) 1 part by mass A monomer dispersion was obtained.

The following formulation was used as a dispersoid, heated to 60 ° C. and dissolved and mixed for 30 minutes.
Styrene monomer 70 parts by mass n-butyl acrylate 30 parts by mass Saturated polyester resin (polycondensate of bisphenol A and terephthalic acid, acid value 10, glass transition point 65 ° C.) 7 parts by mass polyethylene wax (Mw = 1000, Mn = 600, Mw / Mn = 1.7)
20 parts by weight polymerizable monomer dispersion 213 parts by weight

  In this, 10 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was dissolved to prepare a polymerizable monomer composition.

  The polymerizable monomer composition was put into the aqueous dispersion medium in the preliminary dispersion tank 2 and stirred at 100 rpm with a full zone blade (Shinko Pantech Co., Ltd.). A mixed liquid of the aqueous dispersion medium and the polymerizable monomer composition was introduced into the granulator 1 at a flow rate of 60 L / min using the circulation pump 3. A sharp flow mill (manufactured by Taiheiyo Kiko Co., Ltd.) was used as a granulating apparatus having both a first processing part for pre-dispersing as shown in FIG. 2 and a second processing part for finely dispersing the polymerizable monomer composition.

  The setting of the granulator and the granulation conditions were set as follows.

Peripheral speed of the outermost peripheral part of the second rotor group: 68 m / s
Granulator back pressure: 0.3 MPa
The gap between the outermost shells of the rotor group and the stator group of the second processing unit: 0.40 mm
Total length L (m) in the direction of the rotation axis combined with the second processing unit from the first processing unit of the granulator / length l (m) between the first processing unit and the second processing unit: 0.25
Viscosity of polymerizable monomer composition: 20 mPa · s
Granulation was performed for 30 minutes under the above conditions. After the granulation step, the dispersion of the polymerizable monomer composition was heated to 70 ° C. and stirred at 90 rpm with a full zone blade (Shinko Pantech Co., Ltd.) for polymerization for 6 hours. Next, the liquid temperature was raised to 80 ° C. and maintained for 4 hours, and then gradually cooled to 30 ° C. at a cooling rate of 1 ° C. per minute to obtain a slurry. Dilute hydrochloric acid was added to the container containing the slurry to remove the dispersion stabilizer. Further, filtration, washing, drying, and classification were performed to obtain toner particles having a weight average particle diameter of 6.2 μm.

With respect to the obtained polymer particles (100.0 parts by mass), 2.0 parts by mass of hydrophobic silica having a specific surface area by the BET method of 200 m ² / g and a specific surface area by the BET method of 100 m ² / g A toner was obtained by externally adding 0.1 part by mass of certain titanium oxide. The obtained toner was evaluated for image density and fog based on the above evaluation criteria. The results are shown in Table 1.

<Example 2>
Toner particles were obtained in the same manner as in Example 1 except that the peripheral speed of the outermost peripheral portion of the second rotor group of the granulator was 45 m / s. Table 1 shows the viscosity of the polymerizable monomer composition and the results of image evaluation performed on the obtained toner particles in the same manner as in Example 1.

<Example 3>
Toner particles were obtained in the same manner as in Example 1 except that the outer peripheral speed of the second rotor group of the granulator was 90 m / s. Table 1 shows the viscosity of the polymerizable monomer composition and the results of image evaluation performed on the obtained toner particles in the same manner as in Example 1.

<Example 4>
Toner particles were obtained in the same manner as in Example 1 except that the back pressure of the granulator was 0.1 MPa. Table 1 shows the viscosity of the polymerizable monomer composition and the results of image evaluation performed on the obtained toner particles in the same manner as in Example 1.

<Example 5>
Toner particles were obtained by the same method as in Example 1 except that the back pressure of the granulator was 0.6 MPa. Table 1 shows the viscosity of the polymerizable monomer composition and the results of image evaluation performed on the obtained toner particles in the same manner as in Example 1.

<Example 6>
Toner particles were obtained in the same manner as in Example 1 except that the gap between the outer shells of the rotor group and the stator group of the second processing unit of the granulator was 0.10 mm. Table 1 shows the viscosity of the polymerizable monomer composition and the results of image evaluation performed on the obtained toner particles in the same manner as in Example 1.

<Example 7>
Toner particles were obtained in the same manner as in Example 1 except that the gap between the outermost shells of the rotor group and the stator group of the second processing unit of the granulator was 2.0 mm. Table 1 shows the viscosity of the polymerizable monomer composition and the results of image evaluation performed on the obtained toner particles in the same manner as in Example 1.

<Example 8>
Except for adding 24.5 parts by mass of fine powder and coarse powder selected in the classification step of Examples 1 to 7 to the polymerizable monomer composition, and setting the viscosity of the polymerizable monomer composition to 396 mPa · s. Obtained toner particles in the same manner as in Example 1. Table 1 shows the viscosity of the polymerizable monomer composition and the results of image evaluation performed on the obtained toner particles in the same manner as in Example 1.

<Example 9>
The total length L (m) in the rotation axis direction combining the first processing unit to the second processing unit of the granulation apparatus and the length l (m) between the first processing unit and the second processing unit are 1 / L. Toner particles were obtained in the same manner as in Example 1 except that = 0.05. Table 1 shows the viscosity of the polymerizable monomer composition and the results of image evaluation performed on the obtained toner particles in the same manner as in Example 1.

<Example 10>
The total length L (m) in the rotation axis direction combining the first processing unit to the second processing unit of the granulation apparatus and the length l (m) between the first processing unit and the second processing unit are 1 / L. Toner particles were obtained by the same method as in Example 1 except that = 0.5. Table 1 shows the result of image evaluation performed on the obtained toner particles in the same manner as in Example 1.

<Example 11>
Set the granulator and set the granulation conditions.
Granulator back pressure: 0 MPa
The gap between the outermost shells of the rotor group and the stator group of the second processing unit: 3.0 mm
Total length L (m) in the direction of the rotation axis combining the second processing unit from the first processing unit of the granulation apparatus / length l (m) between the first processing unit and the second processing unit: 0.65
Toner particles were obtained in the same manner as in Example 1 except that 25.8 parts by mass of fine powder and coarse powder selected in the classification step of Examples 1 to 7 were added to the polymerizable monomer composition. . Table 1 shows the viscosity of the polymerizable monomer composition and the results of image evaluation performed on the obtained toner particles in the same manner as in Example 1.

<Example 12>
Toner particles were obtained in the same manner as in Example 11 except that the outer peripheral speed of the second rotor group was 68 m / s. Table 1 shows the viscosity of the polymerizable monomer composition and the results of image evaluation performed on the obtained toner particles in the same manner as in Example 1.

<Comparative Example 1>
A circulation system incorporating granulators 20 and 21 shown in FIG. 7 was used. Static mixer (manufactured by Noritake Co., Ltd.) that is a static in-tube mixer as granulator 20 and Ebara Milder (manufactured by Ebara Corporation) that is a high-speed shearing disperser as granulator 21 are static mixers. Then, the mixture of the polymerizable monomer composition and the aqueous dispersion medium was introduced with a circulation pump in series in the order of Ebara Milder. The flow rate at this time was set to 7.1 kg / min, the Weber number of the static mixer was set to 900, the rotation speed of the Ebara milder was set to 10,000 rpm (rotor rotation peripheral speed 11 m / s), and the back pressure was set to 0.3 MPaG. The viscosity of the polymerizable monomer at this time was 22 mPa · s. Except for the above, toner particles were obtained in the same manner as in Example 1. Table 1 shows the result of image evaluation performed on the obtained toner particles in the same manner as in Example 1.

<Comparative Example 2>
A circulation system incorporating granulators 20 and 21 shown in FIG. 7 was used. A fine flow mill (manufactured by Taiheiyo Kiko Co., Ltd.) was used as the granulator 20, and a DISPAX-REACTOR (manufactured by IKA) was used as the granulator 21. The fine flow mill had a rotor rotational peripheral speed of 15 m / s and a DISPAX-REACTOR rotor rotational peripheral speed of 40 m / s, and a mixed liquid of a polymerizable monomer composition and an aqueous dispersion medium was introduced by a circulation pump. The flow rate was set to 60 L / min and the back pressure was set to 0.3 MPaG. The viscosity of the polymerizable monomer at this time was 19 mPa · s. Except for the above, toner particles were obtained in the same manner as in Example 1. Table 1 shows the result of image evaluation performed on the obtained toner particles in the same manner as in Example 1.

<Comparative Example 3>
A circulation system incorporating granulators 20 and 21 shown in FIG. 7 was used. The granulators 20 and 21 used DISPAX-REACTOR (manufactured by IKA). The rotor rotational peripheral speed of DISPAX-REACTOR was set to 40 m / s for both granulators 20 and 21, and a mixed liquid of the polymerizable monomer composition and the aqueous dispersion medium was introduced by a circulation pump. The flow rate was set to 60 L / min and the back pressure was set to 0.3 MPaG. The viscosity of the polymerizable monomer at this time was 19 mPa · s. Except for the above, toner particles were obtained in the same manner as in Example 1. Table 1 shows the result of image evaluation performed on the obtained toner particles in the same manner as in Example 1.

  The present invention is an improved granulation technique for dispersing a polymerizable monomer in an aqueous medium, which can efficiently produce a toner excellent in electrophotographic characteristics by improving the granulation property in the granulation step. It can be suitably used for various toner manufacturing methods.

It is the schematic of the granulation system incorporating the preferable granulation apparatus 1 used for this invention. It is the schematic of a granulation apparatus. It is explanatory drawing of the 1st process part in FIG. 2, and a 2nd process part. It is a perspective view of the 2nd rotor group of the 2nd processing part. It is a perspective view of the stator group of a 2nd process part. FIG. 3 is a cross-sectional view taken along AA ′ in FIG. 2. It is the schematic of the granulation system incorporating the granulation apparatus 20 and 21 used for a comparative example.

Explanation of symbols

1. Granulator 2. 2. Pre-dispersion tank Circulation pump4. 4. Stirring blade Motor 6. 6. Inner wall of the first processing section 7. Supply port for aqueous dispersion medium and polymerizable monomer composition First processing unit 9. Rotating shaft 10. Second processing unit 11. Motor 12. 12. Removal port for processing liquid processed by the granulator 13. Gear-shaped protrusions of the first processing unit Rotor 15. Projection of second rotor group 16. 16. a gap between the protrusions of the second rotor group; Stator 18. Protrusions of stator group 19. 21. Gap between the protrusions of the stator group Granulator 21. Granulator

Claims (7)

A method for producing a toner comprising a granulating step of dispersing a polymerizable monomer composition containing at least a polymerizable monomer and a colorant in an aqueous dispersion medium,
The granulating apparatus used in the granulating step has a two-stage configuration, and the first processing unit is composed of a first rotor group in which rotors having gear-like protrusions are arranged in multiple stages in the rotation axis direction. The two processing parts are coaxial with the first rotor group, and the protrusions are arranged so as to form a circle centered on the rotation axis with a minute gap, and the protrusions are concentrically formed in multiple stages. The two rotor groups are coaxial with the first rotor group, and the protrusions are arranged so as to form a circle around the rotation axis, and the protrusions are concentrically formed in multiple stages. A method for producing toner particles, wherein the stator group is alternately combined with the protrusions.   The mixture of the polymerizable monomer composition and the aqueous dispersion medium passes through the first rotor group in the direction of the second processing section and then passes through the second processing section in the centrifugal direction from the center of the concentric circle. The method for producing toner particles according to claim 1.   3. The toner particle manufacturing method according to claim 1, wherein a peripheral speed S (m / s) of an outermost peripheral portion of the second rotor group is 45 ≦ S ≦ 90.   4. The toner particles according to claim 1, wherein a back pressure P (MPaG) in the granulator is 0.1 ≦ P ≦ 0.6 in the granulation step. 5. Production method.   The gap d (mm) between the projections of the outermost shell in the rotor group and the stator group of the second processing unit is 0.1 ≦ d ≦ 2.0, The method for producing toner particles according to any one of the above.   The total length L (m) in the direction of the rotation axis of the first processing unit and the second processing unit in the granulation apparatus and the length l (m) between the first processing unit and the second processing unit are 0.00. The method for producing toner particles according to claim 1, wherein 05 ≦ l / L ≦ 0.5.   The method for producing toner particles according to claim 1, wherein the polymerizable monomer composition has a viscosity of 400 mPa · s or less.

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