JP2011145321A - Toner for electrostatic charge image development, and method for producing toner for electrostatic charge image development - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development (hereinafter referred to as the toner) having superior low temperature fixability and high transfer efficiency, even in a high temperature and high humidity environment, and giving a printed image of high density, and to provide a method of producing the toner. <P>SOLUTION: The toner for electrostatic charge image development is obtained by aggregating and melt-sticking, in an aqueous medium, resin particles (A) comprising a resin obtained by polymerizing at least a vinyl-based monomer dispersed with an anionic surfactant, resin particles (B) comprising a polyester resin dispersed with an anionic surfactant, and a colorant dispersed with an amphoteric surfactant. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrostatic image developing toner and a method for producing an electrostatic image developing toner.

  From the viewpoint of energy saving, development of low-temperature fixing toner that can be fixed with less energy is in progress. Such a low-temperature fixing toner can be realized by lowering the melting temperature / melting viscosity of the binder resin constituting the toner. However, in order to lower the melting temperature / melting viscosity of the resin, the glass transition point (Tg) and the molecular weight are reduced. As a result, there arise problems such as heat-resistant storage stability of toner and a decrease in fixed image strength. In general, it is known that the use of a polyester resin as the binder resin is superior to the case of using a styrene acrylic resin in terms of both low-temperature fixability and heat-resistant storage stability. This is because polyester resins can be designed for a wide range of molecular weights, and the melting temperature / melting viscosity can be lowered even with a relatively high Tg design, and the compatibility with paper is high. It has been. However, the polyester resin has a high hygroscopic property, and when it is used as a toner, the charge amount is lowered particularly in a high-temperature and high-humidity environment.

  On the other hand, by using a styrene acrylic resin and a polyester resin in combination, a toner that suppresses an increase in hygroscopicity compared to the case of using a polyester resin alone and has better low-temperature fixability than the case of using a styrene acrylic resin alone. A technique for manufacturing the is disclosed. (For example, refer to Patent Document 1).

  However, in the case of an emulsion-association type polymerization toner, when a plurality of types of resins having different physical / chemical characteristics on the surface are aggregated, it is difficult to uniformly aggregate the particles, and the toner has sufficient low-temperature fixability. There was a problem that could not be obtained.

  Further, there has been a problem that the hygroscopicity is increased by exposing the polyester resin to the surface of the toner particles.

  Further, when the ratio of the polyester resin is increased in order to enhance the low temperature fixability, the hygroscopicity is increased, and there is a problem that the transfer rate is lowered in a high temperature and high humidity environment.

  In addition, it is necessary to coagulate the colorant, release agent, charge control agent, etc. in the toner and control the structure at the same time. It is very difficult to control the cohesion, and the colorant is dispersed due to poor control of the cohesion. There was also a problem in that high density prints could not be obtained due to deterioration of properties.

JP 2004-295105 A

  An object of the present invention is an electrostatic charge image developing toner (hereinafter also simply referred to as toner) and a toner that are excellent in low-temperature fixability, maintain high transfer efficiency even in a high-temperature and high-humidity environment, and provide a high-density printed image. It is in providing the manufacturing method of.

  The object of the present invention is achieved by adopting the following configuration.

  1. Resin particles A having a resin obtained by polymerizing at least a vinyl monomer dispersed with an anionic surfactant, resin particles B having a polyester resin dispersed with an anionic surfactant, and an amphoteric surfactant An electrostatic image developing toner obtained by aggregating and fusing a dispersed colorant in an aqueous medium.

  2. 2. The electrostatic image developing toner according to 1 above, wherein the electrostatic image developing toner contains 3 to 50% by mass of the resin particles B.

  3. 3. The electrostatic image developing toner according to 1 or 2, wherein the resin particles A contain a release agent.

  4). A step of producing resin particles A having a resin obtained by polymerizing at least a vinyl monomer dispersed with an anionic surfactant, and a resin particle B having a polyester resin dispersed with an anionic surfactant are produced. An electrostatic charge image comprising: a step; a step of producing a colorant dispersed with an amphoteric surfactant; and a step of aggregating and fusing the resin particles A, resin particles B, and the colorant in an aqueous medium. A method for producing a developing toner.

  5. 5. The method for producing an electrostatic charge image developing toner as described in 4 above, wherein the electrostatic charge image developing toner contains 3 to 50% by mass of the resin particles B.

  The toner and the toner production method of the present invention are excellent in low-temperature fixability, maintain high transfer efficiency even in a high-temperature and high-humidity environment, and have an excellent effect of obtaining a high-density printed image.

1 is a schematic diagram illustrating an example of an image forming apparatus that can use the toner of the present invention.

  The toner obtained by using the disclosed technique is an aggregation scheme using a metal salt (for example, magnesium chloride) for aggregation, so that the hygroscopicity is high, and the transfer rate is deteriorated when printed in a high temperature and high humidity environment. was there.

  In addition, in the aggregation scheme using a metal salt, the low-temperature fixability deteriorates, and it is necessary to increase the ratio of the polyester resin (for example, 51% by mass or more with respect to the toner) in order to ensure the low-temperature fixability. When the ratio of the polyester resin is increased, there is a problem that the hygroscopicity is increased and the transfer rate is lowered.

  Further, in the production process of an emulsion polymerization aggregation type toner, the styrene acrylic resin and the polyester resin often have greatly different aggregation properties due to differences in the acid value / hydroxyl value of the resin, other functional groups, molecular weight distribution, and the like. For this reason, it is difficult for a conventional manufacturing method using a metal salt to cause a polyester resin to be present in a uniformly dispersed state in toner particles, and in particular, a release agent, a colorant, a charge control agent, and the like are aggregated simultaneously. In this case, it is more difficult to control the structure of the toner particles. If the structure cannot be controlled, the target low-temperature fixability cannot be obtained, and a high-density printed image cannot be obtained.

  As a result of intensive studies, the present inventors have resin particles A having a resin obtained by polymerizing at least a vinyl monomer dispersed with an anionic surfactant, and a polyester resin dispersed with an anionic surfactant. The toner obtained by agglomerating and fusing the resin particles B and the colorant dispersed with the amphoteric surfactant in an aqueous medium under acidic conditions has a uniform polyester resin and colorant in the toner particles. It was found to exist in a dispersed state.

  It has been found that printing with this toner is excellent in low-temperature fixability, has little reduction in transfer efficiency even in a high-temperature and high-humidity environment, and a high-density printed image can be obtained.

  In general, particles having different acid values have different dispersion stability under alkaline to neutral conditions. This is considered to be caused by the difference in electrostatic stability due to the difference in the number of carboxyl groups on the particle surface. Therefore, when a plurality of types of particles are aggregated under alkaline to neutral conditions, it is difficult to uniformly aggregate due to the difference in dispersion stability of each particle.

  On the other hand, under acidic conditions, there is no detachment of the carboxyl group on the particle surface, and the dispersion stability of the particle can be controlled by the type and amount of the surfactant used. Therefore, in the manufacturing method, uniform aggregation of a plurality of types of particles is possible.

  In addition, the toner obtained by the above production method is low in hygroscopicity and excellent in low-temperature fixability because the toner particles do not contain metal compared to the toner obtained by the aggregation method using a metal salt. The effect is also obtained.

  The reason for the excellent low-temperature fixability is that the melting temperature / melting viscosity of the resin is reduced by eliminating the ionic cross-linking site generated between the metal and the acid group / hydroxyl group as compared with the case where the toner contains a metal. I guess.

  The present invention will be described below.

<Composition of toner>
The toner of the present invention comprises resin particles A having a resin obtained by polymerizing at least a vinyl monomer dispersed with an anionic surfactant, and resin particles B having a polyester resin dispersed with an anionic surfactant. The colorant dispersed with an amphoteric surfactant is obtained by agglomeration and fusion in an aqueous medium.

The toner of the present invention preferably has a median diameter (D ₅₀ ) of 3.0 to 8.0 μm on a volume basis.

  In the present invention, the amount of the resin particles B forming the toner particles is preferably 3 to 50% by mass, more preferably 5 to 20% by mass based on the total amount of the toner particles.

  In the present invention, toner is a general term for toner particles.

<Resin particles A>
The resin particle A according to the present invention is a resin particle having a resin obtained by polymerizing at least a vinyl monomer, and is used as a main resin constituting the toner particle.

  The resin obtained by polymerizing a vinyl monomer preferably has a glass transition point of 30 to 60 ° C.

  The weight average molecular weight of the resin obtained by polymerizing the vinyl monomer is preferably 8,000 to 50,000, and more preferably 10,000 to 35,000.

  Since the resin obtained by polymerizing the vinyl monomer has a weight average molecular weight of 8,000 to 50,000, the resin has a low content of the oligomer component, which has an adverse effect on heat resistance. Since there is little entanglement of polymer chains and no significant increase in elasticity occurs, it is possible to ensure the gloss and smoothness of the image obtained without reducing the heat resistance. .

  The glass transition point can be measured using a DSC-7 differential scanning calorimeter (manufactured by PerkinElmer) and a TAC7 / DX thermal analyzer controller (manufactured by PerkinElmer).

  As a measurement procedure, 4.5 mg to 5.0 mg of a measurement sample is precisely weighed to two digits after the decimal point, sealed in an aluminum pan, and set in a DSC-7 sample holder. The reference uses an empty aluminum pan. The measurement conditions were a measurement temperature of 0 ° C. to 200 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 10 ° C./min, and heat-cool-heat temperature control. Analysis is performed based on the data in Heat.

  The glass transition point draws an extension of the baseline before the rise of the first endothermic peak and a tangent line indicating the maximum slope between the rise portion of the first peak and the peak apex, and the intersection is defined as the glass transition point. To do.

  The weight average molecular weight can be measured by gel permeation chromatography (GPC). Specifically, using the apparatus “HLC-8220” (manufactured by Tosoh Corporation) and the column “TSKguardcolumnsuperHZ-L + TSKgelSuperHZM-M3 series” (manufactured by Tosoh Corporation), while maintaining the column temperature at 40 ° C., tetrahydrofuran (THF) as a carrier solvent. Is flowed at a flow rate of 0.35 ml / min, and the measurement sample is dissolved in tetrahydrofuran to a concentration of 1 mg / ml under a dissolution condition in which treatment is performed for 5 minutes using an ultrasonic disperser at room temperature, and then the pore size is 0.2 μm. A sample solution is obtained by processing with a membrane filter, and 10 μl of this sample solution is injected into the apparatus together with the carrier solvent described above, detected using a refractive index detector (RI detector), and the molecular weight distribution of the measurement sample is simply determined. Use a calibration curve measured using dispersed polystyrene standard particles. And calculate. Ten polystyrenes are used for calibration curve measurement.

(Vinyl monomer)
Examples of the vinyl monomers used in the present invention include vinyl aromatic monomers, vinyl ester monomers, vinyl ether monomers, olefin monomers, and the like.

  Examples of vinyl aromatic monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-ethyl styrene, pn-butyl styrene, p. Styrene such as tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2,4-dimethyl styrene Examples thereof include system monomers and derivatives thereof.

  Examples of vinyl ester monomers include vinyl acetate, vinyl butyrate, vinyl propionate, and vinyl benzoate.

  Examples of vinyl ether monomers include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, and vinyl phenyl ether.

  Examples of the olefin monomer include monoolefin monomers such as ethylene, propylene, isobutylene, 1-butene, 1-pentene and 4-methyl-1-pentene; diolefin monomers such as butadiene, isoprene and chloroprene. The body can mention.

  Other polymerizable monomers other than the above include acrylic ester monomers such as ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate; methacrylic monomers such as methyl methacrylate, ethyl methacrylate and butyl methacrylate. Acid ester monomers; N-alkyl substituted acrylamides such as N-methylacrylamide and N-ethylacrylamide; nitrile monomers such as acrylonitrile and methacrylonitrile; divinylbenzene, ethylene glycol (meth) acrylate, trimethylolpropane tri A (meth) acrylate etc. can be mentioned.

  The monomer component further contains a crosslinkable vinyl monomer having two or more unsaturated bonds, such as divinylbenzene, divinylnaphthalene, divinyl ether, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate. Also good.

<Resin particle B>
The resin particle B according to the present invention is a resin particle having a polyester resin.

  The polyester resin is used for securing low-temperature fixability and fixing separability, and may be a crystalline polyester resin or an amorphous polyester resin.

When an amorphous polyester resin is used, it is preferable that the storage elastic modulus at 100 ° C. by dynamic viscoelasticity measurement is 10 ³ to 10 ⁸ μN / cm ² , and 10 ⁴ to 10 ⁷ μN / cm ^2. Is more preferable.

The storage elastic modulus is a value obtained by calculation by performing measurement according to the following procedure.
(1) Using a compression molding machine, 0.5 g of the measurement sample is formed into pellets having a diameter of 1 cm. (2) The pellets are loaded on a parallel plate having a diameter of 1 cm set at a gap of 6 mm. The plate gap is set to 3 mm. (4) After setting the measurement part temperature to −20 ° C. with liquid nitrogen, the measurement part is set to 200 ° C. at a temperature rising rate of 5 ° C. while applying a sinusoidal vibration with a frequency of 1.0 Hz. The temperature is raised to ° C. and the complex viscoelastic modulus at a predetermined temperature is measured. The strain angle is controlled by automatic strain control. Automatic strain control checks the measurement state about every 2 to 4 cycles after the start of reading measurement data, and adjusts the strain angle based on the torque peak at that time (average of torque waveform values from 0 to peak) (5) To summarize the above procedure, the storage elastic modulus of the measurement sample can be obtained by measurement under the following conditions. That is,
Measuring device: MR-500 solid meter (manufactured by Rheology Co., Ltd.)
Frequency: 1.0Hz
Plate diameter: 1.0cm (parallel plate)
Gap: 3.0mm
Strain angle: Set to automatic strain control Measurement temperature range: -20 ° C to 200 ° C
On the other hand, when a crystalline polyester resin is used, one having a melting point of 60 to 97 ° C is preferable.

  The melting point is the temperature at the top of the endothermic peak at the time of temperature rise in the endothermic curve in the differential scanning calorimeter (DSC) measurement.

(Non-crystalline polyester resin)
The amorphous polyester resin can be formed using a polyvalent carboxylic acid and a polyhydric alcohol as monomer components.

  Examples of the polyvalent carboxylic acid include terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid and other aromatic carboxylic acids, maleic anhydride, fumaric acid, succinic acid, and alkenyl succinic anhydride. And aliphatic carboxylic acids such as adipic acid and alicyclic carboxylic acids such as cyclohexadicarboxylic acid. These polyvalent carboxylic acids can be used alone or in combination of two or more. Among these polycarboxylic acids, it is preferable to use an aromatic carboxylic acid, and in order to ensure good fixability, a tricarboxylic acid or higher carboxylic acid (trimellitic acid or its acid anhydride) is used together with a dicarboxylic acid. It is preferable to use in combination to form a crosslinked structure or a branched structure.

  Examples of the polyhydric alcohol include aliphatic diols such as butanediol, hexanediol, and glycerin, alicyclic diols such as cyclohexanediol and cyclohexanedimethanol, and polyoxypropylene (2.2) -2,2-bis. Use aromatic diols such as (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, or one or more of these polyhydric alcohols. Can do. Among these polyhydric alcohols, aromatic diols and alicyclic diols are preferable, and among these, aromatic diols are more preferable. Further, in order to ensure good fixability, a trihydric or higher polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol) may be used in combination with the diol in order to take a crosslinked structure or a branched structure.

  In addition, monocarboxylic acid and / or monoalcohol is further added to the non-crystalline polyester resin obtained by polycondensation of polycarboxylic acid and polyhydric alcohol, and hydroxyl group and / or carboxyl group at the polymerization terminal is added. May be esterified to adjust the acid value of the polyester resin. Examples of the monocarboxylic acid include acetic acid, acetic anhydride, benzoic acid, trichloroacetic acid, trifluoroacetic acid, propionic anhydride and the like, and examples of the monoalcohol include methanol, ethanol, propanol, octanol, 2-ethylhexanol, and trifluoroethanol. , Trichloroethanol, hexafluoroisopropanol, phenol and the like.

(Crystalline polyester resin)
In the present invention, the crystalline polyester resin refers to a polyester resin having an endothermic peak when the temperature is increased and an exothermic peak when the temperature is decreased in an endothermic curve obtained by differential scanning calorimetry (DSC) measurement. A crystalline polyester having an endothermic peak when the temperature is raised and having a peak temperature of 60 to 97 ° C. is preferable because it is excellent in low-temperature fixability and filming resistance.

  The crystalline polyester resin can be formed using a polyvalent carboxylic acid or a polyhydric alcohol as a monomer component. In the present invention, aliphatic polyester resins obtained by reacting aliphatic dicarboxylic acids (including acid anhydrides and acid chlorides) with aliphatic diols are preferred.

  Examples of the polyvalent carboxylic acid include oxalic acid, succinic acid, glutaric acid, adipic acid, speric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, and 1,12-dodecane. Dibasic acids such as dicarboxylic acids, aliphatic dicarboxylic acids such as 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, mesaconic acid The aromatic dicarboxylic acid of these is mentioned. Moreover, these anhydrides and lower alkyl esters are also included.

  The polyhydric alcohol suitably used for the crystalline polyester resin is preferably a linear aliphatic diol having 2 to 20 carbon atoms in the main chain portion. The branched type of aliphatic diol reduces the crystallinity of the polyester resin and lowers the melting point. Therefore, the linear type is preferable from the viewpoint of toner blocking resistance, image storage stability, and low-temperature fixability.

  Examples of such aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1, 8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1, Examples thereof include, but are not limited to, 18-octadecanediol and 1,14-eicosandecanediol.

<Colorant>
As the colorant used in the present invention, a known inorganic or organic colorant can be used. Preferred colorants are shown below.

  Examples of the black colorant include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.

  Examples of the colorant for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48; 1, C.I. I. Pigment red 48; 3, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 81; 4, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 222, C.I. I. Pigment red 238 and the like.

  Examples of the colorant for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. And CI Pigment Yellow 138.

  Examples of the colorant for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15; 2, C.I. I. Pigment blue 15; 3, C.I. I. Pigment blue 15; 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue 66, C.I. I. And CI Pigment Green 7.

  These colorants may be used alone or in combination of two or more as required. The addition amount of the colorant is set in the range of 1 to 30% by mass, preferably 2 to 20% by mass with respect to the total mass of the toner.

<Method for producing toner>
A method for producing a toner includes a step of preparing a dispersion of resin particles A having a resin obtained by polymerizing at least a vinyl monomer dispersed with an anionic surfactant, a polyester resin dispersed with an anionic surfactant A step of preparing a dispersion liquid of resin particles B having a colorant, a step of preparing a dispersion liquid of a colorant dispersed with an amphoteric surfactant, and aggregating and fusing the resin particles A, resin particles B, and the colorant in an aqueous medium. A method having a step is preferred.

The toner manufacturing process
(1) A mixed solution containing a vinyl monomer containing a release agent as required is prepared, the mixed solution is converted into oil droplets in an anionic surfactant-containing aqueous medium, and vinyl in the oil droplets is obtained. A step of polymerizing the system monomer by miniemulsion polymerization treatment to produce a dispersion of resin particles A,
(2) A polyester resin is prepared by polymerizing a polymerizable monomer solution having at least a polymerizable polycarboxylic acid component and a polyhydric alcohol component, and the polyester resin is dispersed in an anionic surfactant aqueous medium. Producing a dispersion of resin particles B having a polyester resin,
(3) A step of dispersing a colorant in an aqueous medium containing an amphoteric surfactant to produce a colorant dispersion;
(4) After mixing the dispersion of resin particles A, the dispersion of resin particles B and the dispersion of the colorant, the pH of the mixture is adjusted to agglomerate and melt the resin particles A, the resin particles B, and the colorant. An agglomeration and fusion process for producing a dispersion of associated particles by attaching
(5) A process of adjusting the shape by aging associated particles with thermal energy to obtain a dispersion of toner base particles,
(6) a cooling step for cooling the dispersion of toner base particles;
(7) a washing step of solid-liquid separating the toner base particles from the cooled dispersion of the toner base particles and removing the surfactant and the like from the toner base particles;
(8) a drying step of drying the washed toner base particles;
(9) An external additive adding step of obtaining toner particles by adding an external additive to the dried toner base particles.

  Hereinafter, each step will be described in detail.

<Process for producing dispersion of resin particle A>
First, a polymerizable monomer solution is prepared by dissolving or dispersing a release agent or the like in a vinyl monomer as required.

  In a preferred example for polymerizing a polymerizable monomer, the polymerizable monomer solution is added to an aqueous medium containing an anionic surfactant having a concentration equal to or lower than the critical micelle concentration, and mechanical energy is increased. In addition, oil droplets are formed, and then a polymerization reaction is performed in the oil droplets by radicals from the water-soluble radical polymerization initiator. In the aqueous medium, resin particles may be added as core particles.

  Here, the “aqueous medium” refers to a material whose main component (50% by mass or more) is made of water. Examples of components other than water include organic solvents that dissolve in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran. Among these, alcohol-based organic solvents such as methanol, ethanol, isopropanol, and butanol, which are organic solvents that do not dissolve the resin, are particularly preferable.

  The method of dispersing the polymerizable monomer solution in the aqueous medium is not particularly limited, but a method of dispersing by mechanical energy is preferable, and as a disperser for dispersing oil droplets by mechanical energy. Although there is no particular limitation, for example, “CLEARMIX”, an ultrasonic disperser, a mechanical homogenizer, a manton gourin, a pressure homogenizer and the like can be mentioned. Further, the dispersed particle size (oil droplet size) is preferably 10 to 1000 nm, and more preferably 30 to 300 nm.

<Process for producing dispersion of resin particle B>
The dispersion of the resin particles B is a dispersion having a polyester resin.

  First, a polyvalent carboxylic acid monomer and a polyhydric alcohol monomer are mixed to prepare a polymerization monomer solution. Furthermore, the inside of the reaction system is uniformly stirred while heating, a polycondensation reaction is performed by adding a catalyst, and the polyester resin can be synthesized by continuing the heating while removing generated water.

  A known emulsification method can be used for the production of the aqueous dispersion of the polyester resin. For example, after dissolving the polyester resin in an organic solvent such as ethyl acetate that dissolves the resin without being mixed with water, the polyester resin solution is added to the surfactant aqueous solution, finely dispersed by mechanical means, and then the solvent is removed. Are known. Examples of the mechanical means include an ultrasonic homogenizer (Nippon Seiki Co., Ltd.), a Manton Gorin high-pressure homogenizer (Gorin Inc.), a microfluidizer (Mizuho Industrial Co., Ltd.), Claremix (M Technique Co., Ltd.) and the like.

  The particle size of the polyester resin in the dispersion of the resin particles B is preferably 80 to 400 nm, and more preferably 100 to 250 nm.

<Process for producing a colorant dispersion>
The step of preparing the colorant dispersion is a step of dispersing the colorant particles in an aqueous medium containing an amphoteric surfactant.

  The dispersion treatment of the colorant fine particles is performed in a state where the surfactant concentration is set to a critical micelle concentration (CMC) or more in water. The disperser used for dispersing the colorant fine particles is not particularly limited, but is preferably an ultrasonic disperser, a mechanical homogenizer, a pressure disperser such as a manton gourin or a pressure homogenizer, a sand grinder, a Getzmann mill, or a diamond fine mill. Media type dispersers.

  The colorant fine particles may be surface-modified. The colorant fine particles treated with the surface modifier are reacted by adding the surface modifier to the dispersion in which the colorant fine particles are dispersed and raising the temperature of the system. Can be obtained by filtering, washing and filtering repeatedly with the same solvent and then drying.

<Aggregation / fusion process to obtain associated particles>
In this method, particle growth is performed by mixing resin particles having different electrical polarity and colored particles. And when it grows to a desired particle diameter, pH adjustment is performed to stop the particle growth, and further, heating for controlling the particle shape is continued as necessary.

  In this step, in addition to resin particles and colorant particles, internal additives such as waxes and charge control agents can also be aggregated and fused in the form of particles.

  In the agglomeration / fusion method, an acid such as hydrochloric acid is added to an aqueous medium in which resin particles and colorant particles are present under basic conditions, and the pH is adjusted to the acid side (preferably pH 2 to 4). Next, it is a step of fusing at the same time as agglomeration is advanced by heating to a temperature above the glass transition point of the resin particles. When the desired particle size is reached, a base such as sodium hydroxide is added to bring the pH to the alkali side (preferably pH 7.5 or higher), thereby stopping particle growth. And the shape of particle | grains is controlled by performing heating continuously as needed.

  The “aqueous medium” in this step refers to a material in which the main component (50% by mass or more) is composed of water as described above.

<Cooling process>
This step is a step of cooling the dispersion of colored particles produced in the above-described step, and a rapid cooling treatment is performed at a cooling rate of 1 to 20 ° C./min. Examples of the cooling treatment method used in this step include a method of cooling by introducing a refrigerant from the outside of the reaction vessel, and a method of cooling by directly introducing cold water into the reaction system.

<Washing process>
In this process, after cooling to a predetermined temperature, the toner particles are solid-liquid separated from the cooled dispersion of the toner base particles, and the toner cake obtained by solid-liquid separation (wet toner particles into a cylinder like a cake). This is a cleaning step in which the adhering material such as a surfactant is removed.

  Solid-liquid separation may be carried out by any method other than centrifugation, such as vacuum filtration using a Nutsche or the like, filtration using a filter press or the like.

<Drying process>
This step is a step of drying the washed toner cake. For the drying treatment, a spray dryer, a vacuum freeze dryer, a vacuum dryer or the like can be used. The water content of the dried toner base particles is preferably 1% by mass or less, and more preferably 0.5% by mass or less. In addition, when the dried toner base particles are aggregated with a weak interparticle attractive force, the aggregate may be crushed by a jet mill, a Henschel mixer, or the like.

<External additive addition process>
This step is a step of mixing an external additive with the toner base particles obtained by drying. An electrostatic charge image developing toner can be obtained by mixing an external additive with the toner base particles.

  In the case where it is not necessary to add an external additive, the toner base particles can be used as the toner as they are.

  Next, members used in the toner manufacturing process will be described.

"Element"
(Anionic surfactant)
Examples of the anionic surfactant used in preparing the dispersion of resin particles A and the dispersion of resin particles B include aliphatic soaps such as sodium stearate and sodium laurate, sodium lauryl sulfate, and dodecylbenzene sulfonic acid. Sodium, polyoxyethylene (2) sodium lauryl ether sulfate, etc. can be mentioned.

(Amphoteric surfactant)
Examples of the amphoteric surfactant used in preparing the colorant dispersion include N-alkylnitrilotriacetic acid, N-alkyldimethyl N oxide, α-trimethylammonio fatty acid, N-alkyl-β-aminopropionate, N -Alkyl-β-iminopropionate, N-alkyl-oxymethyl-N, N-diethyl N oxide, N-alkyl-N, N-diaminoethylglycine hydrochloride, 2-alkylimidazoline derivatives, aminoethylimidazoline organic acid Examples thereof include salts, N-alkylsulfo N oxides, N-alkyl taurine salts, amidopropyl betaine laurate, and betaine lauryl dimethylaminoacetate.

(Release agent)
The toner of the present invention can contain a release agent as required. The release agent can be contained in the resin particles A or can be added as the release agent particles simultaneously with the resin particles and the colorant particles in the aggregation / fusion process.

  As the mold release agent, for example, polypropylene and polyethylene as the polyolefin wax, and paraffin wax, Fischer-Tropsch wax, microcrystalline wax, and metallocene wax are preferable as conventional names after the production method. Other examples include fatty acid wax having 12 to 24 carbon atoms and ester compounds thereof, higher alcohol wax, lanolin wax, carnauba wax, rice wax, beeswax, scale insect wax, and montan wax.

  Examples of the method for containing the release agent in the resin particles A include a method of polymerizing a dispersion in which a dispersion (wax emulsion) of release agent fine particles is previously contained in a polymerizable monomer solution. .

  The content ratio of the release agent in the toner particles is preferably 5 to 30% by mass, and more preferably 10 to 20% by mass with respect to the total mass of the toner.

(Chain transfer agent)
In the polymerization step, a general chain transfer agent can be used for the purpose of adjusting the molecular weight of the resin particles A. Examples of the chain transfer agent include mercaptans such as 2-chloroethanol, octyl mercaptan, dodecyl mercaptan, and t-dodecyl mercaptan, and styrene dimers.

(Polymerization initiator)
In the polymerization step, a suitable polymerization initiator for obtaining the resin particles A can be used as long as it is a water-soluble polymerization initiator. Examples of the polymerization initiator include persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds (4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane). ) Salt), peroxide compounds and the like.

(Charge control agent)
The resin particles A and resin particles B constituting the toner of the present invention may contain a charge control agent as necessary. Various known compounds can be used as the charge control agent.

(catalyst)
Examples of the catalyst for the synthesis of the polyester resin include the following, but are not limited thereto. Examples of the titanium catalyst include titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, and the like.

  Other catalysts include alkali metal compounds such as sodium and lithium, alkaline earth metal compounds such as magnesium and calcium, metal compounds such as zinc, manganese, antimony, tin, zirconium and germanium, phosphite compounds, phosphate compounds And amine compounds.

<Developer>
The toner of the present invention can be used as a two-component developer composed of a carrier and a toner, or as a non-magnetic one-component developer composed only of a toner.

  Carriers that are magnetic particles used when used as a two-component developer are conventionally known materials such as metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead. It is possible to use. Among these, ferrite particles are preferable. Further, as the carrier, a coated carrier in which the surface of the magnetic particles is coated with a coating agent such as a resin, a resin dispersion type carrier in which a magnetic fine powder is dispersed in a binder resin, or the like may be used. The carrier has a volume average particle size of preferably 15 to 100 μm, more preferably 25 to 80 μm.

  Next, an image forming method and an image forming apparatus that can use the toner of the present invention will be described.

<Image forming method>
The toner of the present invention can be used in various known electrophotographic image forming methods. For example, the image forming method can be used for a monochrome image forming method or a full color image forming method. In the full color image forming method, four types of color developing devices for yellow, magenta, cyan, and black, and one electrostatic latent image are used. A four-cycle image forming method including an image carrier (hereinafter also simply referred to as an image carrier), a color developing device for each color, and an image forming unit having an electrostatic latent image carrier are provided for each color. The image forming method can be used for any image forming method such as a tandem image forming method.

  FIG. 1 is a schematic view showing an example of an image forming apparatus using the toner of the present invention.

  In FIG. 1, 1Y, 1M, 1C and 1K are photoreceptors, 4Y, 4M, 4C and 4K are developing devices, 5Y, 5M, 5C and 5K are primary transfer rolls as primary transfer means, and 5A is a secondary transfer. Secondary transfer rolls as means, 6Y, 6M, 6C and 6K are cleaning devices, 7 is an intermediate transfer member unit, 24 is a heat roll type fixing device, and 70 is an intermediate transfer member.

  This image forming apparatus is called a tandem color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an endless belt-shaped intermediate transfer body unit 7 as a transfer unit, and a recording member P. An endless belt-shaped sheet feeding / conveying means 21 and a heat roll type fixing device 24 as a fixing means. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  As one of the different color toner images formed on each photoconductor, an image forming unit 10Y that forms a yellow image includes a drum-shaped photoconductor 1Y as a first image carrier, and the photoconductor 1Y. A charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, a primary transfer roll 5Y as a primary transfer unit, and a cleaning unit 6Y are arranged around the periphery. In addition, an image forming unit 10M that forms a magenta image as another different color toner image is a drum-shaped photoconductor 1M as a first image carrier, and is arranged around the photoconductor 1M. The charging unit 2M, the exposure unit 3M, the developing unit 4M, the primary transfer roll 5M as the primary transfer unit, and the cleaning unit 6M are provided. In addition, an image forming unit 10C that forms a cyan image as another different color toner image includes a drum-shaped photoconductor 1C as a first image carrier, and around the photoconductor 1C. A charging unit 2C, an exposure unit 3C, a developing unit 4C, a primary transfer roll 5C as a primary transfer unit, and a cleaning unit 6C are disposed. In addition, an image forming unit 10K that forms a black image as one of other different color toner images is disposed around a drum-shaped photoconductor 1K as a first image carrier and the photoconductor 1K. A charging unit 2K, an exposure unit 3K, a developing unit 4K, a primary transfer roll 5K as a primary transfer unit, and a cleaning unit 6K.

  The endless belt-like intermediate transfer body unit 7 has an endless belt-like intermediate transfer body 70 as an intermediate transfer endless belt-like second image carrier that is wound around a plurality of rolls and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred onto the rotating endless belt-shaped intermediate transfer body 70 by the primary transfer rolls 5Y, 5M, 5C, and 5K, and is combined. A colored image is formed. A recording member P such as a sheet as a transfer material accommodated in the sheet feeding cassette 20 is fed by the sheet feeding / conveying means 21, passes through a plurality of intermediate rolls 22 A, 22 B, 22 C, 22 D, and a registration roll 23, and is secondary. A color image is transferred onto the recording member P at a time by being conveyed to a secondary transfer roll 5A as a transfer means. The recording member P to which the color image has been transferred is fixed by the heat roll type fixing device 24, is sandwiched by the paper discharge roll 25, and is placed on the paper discharge tray 26 outside the apparatus.

  On the other hand, after the color image is transferred to the recording member P by the secondary transfer roll 5A, the residual toner is removed from the endless belt-shaped intermediate transfer body 70 from which the recording member P is separated by the curvature by the cleaning means 6A.

  During the image forming process, the primary transfer roll 5K is always in pressure contact with the photoreceptor 1K. The other primary transfer rolls 5Y, 5M, and 5C are in pressure contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roll 5A comes into pressure contact with the endless belt-shaped intermediate transfer body 70 only when the recording member P passes through the secondary transfer roll 5A and secondary transfer is performed.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10K, and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10K are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1K in the figure. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rolls 71, 72, 73, 74, and 76, primary transfer rolls 5Y, 5M, 5C, and 5K, and a cleaning unit. 6A.

  The image forming units 10Y, 10M, 10C, and 10K and the endless belt-shaped intermediate transfer body unit 7 are integrally pulled out from the main body A by the drawer operation of the housing 8.

  In this way, toner images are formed on the photoreceptors 1Y, 1M, 1C, and 1K by charging, exposure, and development, and the toner images of the respective colors are superimposed on the endless belt-shaped intermediate transfer body 70, and are collectively applied to the recording member P. The image is transferred and fixed by the fixing device 24 by pressing and heating. The photoreceptors 1Y, 1M, 1C, and 1K after the toner image is transferred to the recording member P are cleaned by the cleaning devices 6Y, 6M, 6C, and 6K after the toner remaining on the photoreceptor at the time of transfer is cleaned. Then, the exposure and development cycles are entered, and the next image formation is performed.

  Although the embodiment of the present invention will be specifically described, the present invention is not limited to this embodiment.

  The toner of the present invention was produced as follows.

<< Dispersion of Resin Particle A >>
<Dispersion of resin particle A1>
(1) First-stage polymerization A reaction vessel equipped with a stirrer, a temperature sensor, a temperature controller, a cooling tube, and a nitrogen introduction device was charged with 2.0 parts by mass of an anionic surfactant “sodium lauryl sulfate” in advance with ion-exchanged water 2900 An anionic surfactant solution dissolved in mass parts was charged, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.

After adding 9.0 parts by mass of a polymerization initiator “potassium persulfate: KPS” to this surfactant solution and adjusting the internal temperature to 78 ° C.,
Solution (1)
Styrene 540 parts by weight n-butyl acrylate 270 parts by weight Methacrylic acid 65 parts by weight n-octyl mercaptan 17 parts by weight of solution (1) was added dropwise over 3 hours, and after completion of the addition, heating and stirring at 78 ° C. for 1 hour Thus, polymerization (first stage polymerization) was performed to prepare a dispersion of “resin fine particles (a1)”.
(2) Second stage polymerization: formation of an intermediate layer In a flask equipped with a stirrer,
Solution (2)
Styrene 94 parts by weight n-butyl acrylate 60 parts by weight Methacrylic acid 11 parts by weight n-octyl mercaptan 5 parts by weight Paraffin wax (melting point: 73 ° C.) 51 parts by weight as a release agent was added, A monomer solution (2) was prepared by heating to 85 ° C. and dissolving.

On the other hand, a surfactant solution in which 2 parts by mass of the anionic surfactant “sodium lauryl sulfate” was dissolved in 1100 parts by mass of ion-exchanged water was heated to 90 ° C., and “resin fine particles (a1)” was added to this surfactant solution. Is added in an amount of 28 parts by mass in terms of solid content of the resin fine particles (a1), and then the monomer solution (Cleamix) (manufactured by M Technique Co., Ltd.) having a circulation path is used. 2) is mixed and dispersed for 4 hours to prepare a dispersion containing emulsified particles having a dispersed particle diameter of 350 nm. In this dispersion, 2.5 parts by mass of the polymerization initiator “KPS” is dissolved in 110 parts by mass of ion-exchanged water. The initiator aqueous solution was added, and this system was heated and stirred at 90 ° C. for 2 hours to perform polymerization (second stage polymerization) to prepare a dispersion of “resin fine particles (a11)”.
(3) Third-stage polymerization: formation of outer layer Initiator aqueous solution in which 2.5 parts by mass of polymerization initiator “KPS” was dissolved in 110 parts by mass of ion-exchanged water in the dispersion of “resin fine particles (a11)”. And at a temperature of 80 ° C.
Solution (3)
Styrene 230 mass parts n-butyl acrylate 100 mass parts n-octyl mercaptan Solution (3) which consists of 5.2 mass parts was dripped over 1 hour. After completion of the dropwise addition, polymerization (third stage polymerization) was carried out by heating and stirring for 3 hours. Then, it cooled to 28 degreeC and produced "the dispersion liquid of the resin particle A1" in which the resin particle A1 was disperse | distributed in the anionic surfactant solution.

<Preparation of resin particle A2> (for comparison)
“Resin particles for comparison” in the same manner except that the anionic surfactant “sodium lauryl sulfate” used in the preparation of the dispersion of resin particles A1 is changed to “amphoteric surfactant lauryldimethylaminoacetic acid betaine”. A2 dispersion "was prepared.

<< Dispersion of Resin Particle B >>
<Dispersion of resin particle B1>
(Synthesis of non-crystalline polyester resin)
A total of 3 parts by mass of the following polycarboxylic acid monomer and polyhydric alcohol monomer were mixed in a flask equipped with a stirrer, a nitrogen introduction tube, a temperature controller, and a rectifying column to prepare a reaction solution. The reaction solution was heated to 190 ° C. over 1 hour, and after confirming that the reaction system was uniformly stirred, the catalyst Ti (OBu) ₄ (total amount of the carboxylic acid component of the non-crystalline polyester resin was adjusted. In contrast, 0.003 mass%) was added.

Reaction liquid (polycarboxylic acid monomer)
Terephthalic acid 12.50 parts by weight Fumaric acid 13.90 parts by weight Isophthalic acid 0.55 parts by weight Trimellitic acid 5.20 parts by weight (polyhydric alcohol monomer)
Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane
76 parts by mass Polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane
24 parts by mass While distilling off the generated water, the temperature was raised from the same temperature to 240 ° C. over 6 hours, and the dehydration-condensation reaction was continued at 240 ° C. for another 6 hours. A crystalline polyester resin "was obtained.

  As a result of measuring the thermal characteristics of the obtained amorphous polyester resin using a differential scanning calorimeter “DSC-7” (manufactured by Shimadzu Corporation) at a temperature rising rate of 3 ° C./min, the secondary transition The temperature Tg was 64 ° C.

100 parts by mass of the obtained “amorphous polyester resin” was dissolved in 400 parts by mass of ethyl acetate (manufactured by Kanto Chemical Co., Inc.) and mixed with 638 parts by mass of a 0.26% by mass sodium lauryl sulfate solution prepared in advance. While stirring, ultrasonically disperse with an ultrasonic homogenizer “US-150T” (manufactured by Nippon Seiki Seisakusho) at V-LEVEL 300 μA for 30 minutes, and heated to 40 ° C., a diaphragm vacuum pump V-700 (BUCHI) The ethyl acetate was completely removed while stirring under reduced pressure for 3 hours, and the average particle size (volume-based median diameter (D ₅₀ )) was 160 nm, and the solid content was 13.5 parts by mass. A “dispersion of resin particles B1” was obtained.

(Dispersion of resin particle B2)
(Synthesis of crystalline polyester resin)
In a three-necked flask, 10 parts by mass of 1,9-nonanediol and 10 parts by mass of 1,10-dodecanedioic acid and catalyst Ti (OBu) ₄ (0.014% by mass with respect to the carboxylic acid component of the crystalline polyester resin) After that, the air in the container was decompressed by a decompression operation.

  Further, under an inert atmosphere with nitrogen gas, the mixture was refluxed at 180 ° C. for 6 hours with mechanical stirring. Thereafter, unreacted monomer components are removed by distillation under reduced pressure, the temperature is gradually raised to 220 ° C., and the mixture is stirred for 12 hours. Sampling was performed when the mixture became viscous to obtain a “crystalline polyester resin”.

  When the obtained crystalline polyester resin was measured for thermal characteristics at a temperature rising rate of 3 ° C./min with a differential scanning calorimeter “DSC-7” (manufactured by Shimadzu Corporation), the maximum endothermic peak temperature, that is, the melting point was 75 ° C. It was.

  Using the obtained “crystalline polyester resin”, a “dispersion of resin particles B2” was prepared in the same manner as the dispersion of resin particles B1.

<Preparation of dispersion of resin particle B3>
50 parts by mass of the “dispersion of resin particle B1” produced above and 50 parts by mass of “dispersion of resin particle B2” were mixed to produce “dispersion of resin particle B3”.

<Preparation of dispersion of resin particle B4> (for comparison)
“Dispersion of resin particles B4” was similarly performed except that the anionic surfactant “sodium lauryl sulfate” used in the preparation of the dispersion of resin particles B1 was changed to “amphoteric surfactant lauryldimethylaminoacetic acid betaine”. Liquid "was prepared.

<< Preparation of Colorant Dispersion >>
<Preparation of Colorant Dispersion 1>
Add 90 parts by weight of amphoteric surfactant “lauryldimethylaminoacetic acid betaine” into 1600 parts by weight of ion-exchanged water and dissolve with stirring, and then add 5 mol / liter sodium hydroxide aqueous solution to adjust pH to 10. did. While stirring this amphoteric surfactant solution, 420 parts by mass of carbon black “Mogal L” (manufactured by Cabot) is gradually added, and then a mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.) is used. Then, a colorant dispersion was prepared by dispersion treatment. This is designated as “colorant dispersion 1”. The particle diameter of the colorant in “Colorant Dispersion A” was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.) and found to be 110 nm.

<Preparation of Colorant Dispersion 2> (for comparison)
90 parts by mass of “sodium lauryl sulfate” which is an anionic surfactant was added to 1600 parts by mass of ion-exchanged water and dissolved by stirring. While stirring this liquid, 420 parts by mass of carbon black “Mogal L” (Cabot Corporation) is gradually added, and then dispersed using a mechanical disperser “CLEARMIX” (M Technique Co., Ltd.). Thus, a colorant dispersion was prepared. This is designated as “Colorant Dispersion B”. The particle diameter of the colorant in “Colorant Dispersion 2” was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.) and found to be 110 nm.

<Production of toner>
<Preparation of Toner 1>
(Aggregation / fusion process)
In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, a temperature control device, and a nitrogen introduction device, 348 parts by mass of the dispersion of “resin particle A1” in solid content and the dispersion of “resin particle B1” are solid. After adding 12 parts by mass and 2000 parts by mass of ion-exchanged water, the pH was adjusted to 10 by adding a 5 mol / liter aqueous sodium hydroxide solution. Thereafter, 40 parts by mass of “colorant dispersion 1” was added in terms of solid content, and a 5 mol / liter hydrochloric acid aqueous solution was added to adjust the pH to 3.

Thereafter, aggregation and fusion were performed by raising the temperature. In this state, the particle size of the aggregated particles was measured using “Multisizer 3” (manufactured by Beckman Coulter), and when the volume-based median diameter (D ₅₀ ) reached 6.6 μm, 5 mol / liter. Sodium hydroxide aqueous solution was added to adjust the pH to 8, and the particle growth was stopped. Furthermore, the temperature is raised, and the particles are further fused by heating and stirring at 90 ° C., and the average circularity measurement apparatus “FPIA-2100” (manufactured by Sysmex) is used (HPF). The number of detection was 4000) When the average circularity reached 0.945, the temperature was cooled to 30 ° C. to prepare “dispersion of toner base particle 1”.

(Washing / drying process)
The dispersion of toner base particles 1 produced in the aggregation / fusion process was subjected to solid-liquid separation using a basket-type centrifuge to form a wet cake of toner base particles. This wet cake is washed with ion exchange water at 35 ° C. until the electrical conductivity of the filtrate reaches 5 μS / cm with a basket-type centrifuge, and then transferred to a “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.). Was dried to 0.5 wt% to produce “toner base particle 1”.

(External additive treatment process)
1% by mass of hydrophobic silica (number average primary particle size = 12 nm) and 0.3% by mass of hydrophobic titania (number average primary particle size = 20 nm) are added to the “toner base particle 1”, and a Henschel mixer is used. By mixing, “Toner 1” was produced.

<Preparation of Toners 2-7>
“Toners 2 to 7” were prepared in the same manner except that the types and mass parts of “resin particles A” and “resin particles B” used in the preparation of toner 1 were changed as shown in Table 1.

<Preparation of Toners 8-9> (Comparative Example)
“Toners 8 to 9” were produced in the same manner except that the types and mass parts of “resin particles A” and “resin particles B” used in the production of toner 1 were changed as shown in Table 1.

<Preparation of Toner 10> (Comparative Example)
An attempt was made to produce “Toner 10” in the same manner except that “Colorant Dispersion Liquid 1” used in the production of Toner 3 was changed to “Colorant Dispersion Liquid 2”, but the toner could not be synthesized.

<Preparation of Toner 11> (Comparative Example)
(Aggregation / fusion process)
In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device, a dispersion of “resin particles A1” is 280 parts by mass in terms of solids, and a dispersion of “resin particles B1” is in terms of solids 80 After adding parts by mass and 2000 parts by mass of ion-exchanged water, a 5 mol / liter sodium hydroxide aqueous solution was added to adjust the pH to 10.

Thereafter, 40 parts by mass of “colorant dispersion 2” was added in terms of solid content. Next, an aqueous solution in which 60 parts by mass of magnesium chloride was dissolved in 60 parts by mass of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. Thereafter, the temperature was raised after being allowed to stand for 3 minutes, and the temperature of the system was raised to 80 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 80 ° C. In this state, the particle size of the associated particles was measured with “Coulter Multisizer 3” (manufactured by Coulter Beckman). When the median diameter (D ₅₀ ) on the volume basis reached 6.6 μm, 190 parts by mass of sodium chloride was added. An aqueous solution dissolved in 760 parts by mass of ion-exchanged water was added to stop particle growth. Further, the temperature is raised and the mixture is heated and stirred in a state of 90 ° C. to advance the fusing of the particles, and the average circularity measurement apparatus “FPIA-2100” (manufactured by Sysmex) is used (HPF detection). When the average circularity reached 0.945, the mixture was cooled to 30 ° C. to prepare “dispersion of toner base particle 11”.

  “Toner 11” was prepared in the same manner as toner 1 after the washing and drying steps.

<Preparation of Toner 12> (Comparative Example)
“Toner 12” was prepared in the same manner except that “resin particle B” was not used in the preparation of toner 1 and the mass part of “resin particle A” was changed as shown in Table 1.

  Table 1 shows the types and parts by mass of “resin particles A”, “resin particles B”, and “colorants” used in the production of the toner.

<Production of developer>
100 parts by mass of ferrite core and 5 parts by mass of copolymer resin particles of cyclohexyl methacrylate / methyl methacrylate (copolymerization ratio 5/5) are put into a high-speed mixer equipped with stirring blades and stirred and mixed at 120 ° C. for 30 minutes. Then, a resin coat layer was formed on the surface of the ferrite core by the action of mechanical impact force, and a carrier having a volume-based median diameter of 40 μm was produced.

  The volume-based median diameter of the carrier was measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by Sympathic) equipped with a wet disperser.

  “Toners 1 to 12” prepared above are added to the carrier so that the toner concentration is 6% by mass, respectively, and are added to a “micro type V type mixer” (Tsutsui Rikenki Co., Ltd.). Mixing was performed at 45 rpm for 30 minutes to prepare “Developers 1 to 12”.

<Evaluation>
As an image forming apparatus for evaluation, a copier “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies) was used.

  The fixing device used was modified so that the surface temperature of the heating roller could be changed in increments of 10 ° C. within the range of 120 to 170 ° C.

Each of the toner and the developer prepared above was sequentially loaded in this image forming apparatus, and printing was performed on A4 size high-quality paper (64 g / m ² ).

<Low temperature fixability>
The low-temperature fixability is a 1 cm square solid prepared by fixing at 10 ° C. increments in the range of 120 to 170 ° C. of the surface temperature of the heating roller of the fixing device in a normal temperature and humidity environment (20 degrees, 50% RH). Images (one at the center) were printed and evaluated. The evaluation was performed by rubbing the solid image portion of 1 cm square three times with “JK Wiper” (manufactured by Crecia Co., Ltd.) under a pressure of 10 kPa, using the stain on the surface of the JK wiper and the density reduction rate of the solid image. The solid image density reduction rate is obtained by measuring the density of a solid image after printing and the density of a solid image after rubbing with a reflection densitometer “RD-918” (manufactured by Macbeth), and calculating the solid image density after printing. The value obtained by dividing the value obtained by subtracting the solid image density after rubbing by the solid image density after printing is a numerical value expressed in%. The evaluation criteria are 基準 and ◎.

Evaluation Criteria A: There is no stain on the surface of the JK wiper, and the solid image has a decrease in density of less than 5%. Good: A stain on the surface of the JK wiper is slightly observed, and the decrease in the density of the solid image is 5% or more and less than 10%. No problem in practical use x: Dirt on the surface of the JK wiper was observed, and there was a problem with a solid image density reduction of 10% or more.

<Transfer efficiency>
The transfer efficiency is as follows: a 10 cm square solid image is printed in a high temperature and high humidity environment (30 ° C., 80% RH), developed on the image carrier (photoreceptor) and attached to the mass of black toner The mass of the black toner transferred and adhered to the toner was measured, and the transfer efficiency defined by the following formula was calculated and evaluated. The transfer efficiency is 80% or more.

Transfer efficiency = Amount of black toner adhering to fine paper / Amount of black toner adhering to photoconductor × 100 (%)
<Image density>
As for the image density, a solid image of 10 cm square is printed under normal temperature and normal humidity (20 ° C., 50% RH), and the density of the solid black image portion is measured using a reflection densitometer “RD-918” (manufactured by Macbeth). Twelve points were measured and evaluated based on the average concentration. The image density is 1.40 or more as acceptable.

  Table 2 shows the evaluation results.

  From the evaluation results in Table 2, it can be seen that “toners 1 to 7” of “Examples 1 to 7” of the present invention have no problem in all evaluation items. On the other hand, it can be seen that “Toners 8 to 12” of “Comparative Examples 1 to 5” of the present invention have a problem in any of the evaluation items, and the object of the present invention cannot be achieved.

1Y, 1M, 1C, 1K Photoconductor 4Y, 4M, 4C, 4K Developing device 5Y, 5M, 5C, 5K Primary transfer roll as primary transfer means 5A Secondary transfer roll as secondary transfer means 6Y, 6M, 6C, 6K Cleaning device 7 Intermediate transfer member unit 10Y, 10M, 10C, 10K Image forming portion 21 Endless belt-like paper feeding / conveying means 24 Heat roll type fixing device 70 Intermediate transfer member P Recording member

Claims (5)

Resin particles A having a resin obtained by polymerizing at least a vinyl monomer dispersed with an anionic surfactant, resin particles B having a polyester resin dispersed with an anionic surfactant, and an amphoteric surfactant An electrostatic image developing toner obtained by aggregating and fusing a dispersed colorant in an aqueous medium. 2. The electrostatic image developing toner according to claim 1, wherein the electrostatic image developing toner contains 3 to 50 mass% of the resin particles B. 3. The electrostatic charge image developing toner according to claim 1, wherein the resin particles A contain a release agent. A step of producing resin particles A having a resin obtained by polymerizing at least a vinyl monomer dispersed with an anionic surfactant, and a resin particle B having a polyester resin dispersed with an anionic surfactant are produced. An electrostatic charge image comprising: a step; a step of producing a colorant dispersed with an amphoteric surfactant; and a step of aggregating and fusing the resin particles A, resin particles B, and the colorant in an aqueous medium. A method for producing a developing toner. The method for producing a toner for developing an electrostatic charge image according to claim 4, wherein the toner for developing an electrostatic charge image contains 3 to 50% by mass of the resin particles B.

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