JP2007052399A - Method of manufacturing toner, toner and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymerized toner comprising a polyester resin and a styrene-acrylic resin, excellent in fixability such as low-temperature fixability and thin line reproducibility in image formation, and capable of stably forming high quality images over a prolonged period of time, and a method of manufacturing such a toner and an image forming method. <P>SOLUTION: The method of manufacturing a toner comprises: a polymerization step of obtaining composite resin particles by forming oil droplets in an aqueous medium comprising a surfactant having a long chain hydrocarbon group and an acid group, the oil droplets comprising: a polycarboxylic acid, a polyhydric alcohol, a styrene compound and a (meth)acrylate ester compound, and carrying out in the oil droplets a step of forming a polyester resin from the polycarboxylic acid and the polyhydric alcohol and a step of forming a styrene-acrylic resin from the radically polymerizable monomers; and a coagulation step of coagulating at least the composite resin particles in an aqueous medium. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a toner manufacturing method, a toner obtained by the manufacturing method, and an image forming method.

  When an image is formed by an electrophotographic image forming method, the toner is required to have a small particle size in order to improve the image quality, and a polymerized toner is manufactured in response to this request. This polymerized toner is a colored particle obtained by agglomerating particles of toner constituents such as resin particles, colorant particles and other particles as required, obtained through a polymerization process such as an emulsion polymerization method. It is comprised by the toner particle by.

  Conventionally, as resin particles for obtaining a polymerized toner, oil droplets are formed by dispersing raw material polymerizable monomers in an aqueous medium containing an emulsifier to form oil droplets, and adding a polymerization initiator. Examples include styrene-acrylic resin particles prepared by an emulsion polymerization method in which radical copolymerization is performed in (see, for example, Patent Document 1 and Patent Document 2).

  However, in such a toner production method, since the types of monomers that can be used for radical copolymerization are limited, the toner obtained is made of toner particles made of vinyl resin particles or acrylic resin particles. It will be limited to what.

The polyester resin has high crystallinity and high hardness, so that excellent viscoelasticity is obtained, and the formed toner has excellent fixability to a transfer material. On the other hand, since styrene-acrylic resins have non-crystalline properties and a low softening point temperature, they are softened early at low temperatures, so that good low-temperature fixability can be obtained.
A toner containing toner particles in which a polyester resin and a styrene-acrylic resin are mixed is desired so as to have the advantages of both the polyester resin and the styrene-acrylic resin. In order to obtain, for example, a method has been proposed in which both resins are mixed, melted and kneaded (see, for example, Patent Document 3).

However, in the conventional method in which both resins are melted and kneaded, the structure of the polyester resin and the styrene-acrylic resin is greatly different, so that it is difficult to mix with high uniformity, and the step of pulverizing the resulting mixed resin In the image formed, the toner detachment phenomenon occurs or the toner obtained has a large variation in the resin composition between the toner particles, resulting in a broad charge amount distribution and a small charge amount in the formed image. There is a problem that abnormal images such as fogging and toner scattering estimated to be caused by the toner may occur.
JP 2000-214629 A JP 2001-125313 A JP-A-6-3856

  The present invention has been made based on the above circumstances, and an object of the present invention is a polymerized toner containing hybrid resin particles made of a polyester resin and a styrene-acrylic resin. A toner manufacturing method which is excellent in fixing property such as low temperature fixing property in the fixing step and fine line reproducibility, can stably form a high-quality image over a long period of time, and can be easily prepared; and An object of the present invention is to provide a toner obtained by this toner manufacturing method and an image forming method using the toner.

The toner production method of the present invention comprises at least one divalent or higher carboxylic acid and at least one kind in an aqueous medium containing a surfactant composed of a compound having a long-chain hydrocarbon group and an acidic group. For forming hybrid resin particles comprising a polycondensable monomer comprising a divalent or higher alcohol, and a radical polymerizable monomer comprising at least one styrene compound and at least one (meth) acrylic ester compound Forming oil droplets of the composition;
In the oil droplet, a polycondensation step of synthesizing a polyester resin by subjecting the carboxylic acid and the alcohol to a polycondensation reaction and a radical copolymerization reaction of the styrene compound and the (meth) acrylic ester compound to produce a styrene-acrylic A polymerization step of obtaining hybrid resin particles containing a polyester resin and a styrene-acrylic resin by performing a radical copolymerization step of synthesizing a resin based on
A coagulation step of coagulating at least the hybrid resin particles in an aqueous medium.

  In the method for producing a toner of the present invention, the acidic group of the surfactant is preferably any one of a sulfonic acid group, a phosphoric acid group and a carboxylic acid group, and the surfactant contained in the aqueous medium However, it is preferable that it is below a critical micelle density | concentration, and it is preferable that the compound which concerns on surfactant has a C8-C40 hydrocarbon group.

  In the toner manufacturing method of the present invention, it is preferable that the aggregation step is performed in an aqueous medium in which the polymerization step has been performed.

  In the toner production method of the present invention, the polycondensable monomer preferably contains at least one trivalent or higher carboxylic acid and / or at least one trivalent or higher alcohol.

The toner of the present invention is obtained by the toner production method described above.
In the toner of the present invention, the ratio of toner particles having a shape factor in the range of 1.0 to 1.6 is preferably 65% by number or more with respect to the toner particles based on the colored particles. The toner particles are preferably composed of toner particles having a variation coefficient of shape factor of 16% or less, and the toner particles of the colored particles are composed of toner particles having a number variation coefficient of 27% or less in the number particle size distribution. It is preferable that the ratio of colored particles having no corners is 50% by number or more.

  In the image forming method including the step of developing the latent image formed on the latent image carrier with a developer containing toner and visualizing the latent image, the toner is used as the toner. An image forming method.

  As a result of diligent investigations, the present inventors have dispersed a solution in which raw materials of both resins are dissolved in a so-called monomer stage in an aqueous medium as a means for solving the problems associated with the mixing of the polyester resin and the styrene-acrylic resin. To form oil droplets, then to synthesize polyester resin by condensation polymerization reaction, and to synthesize styrene-acrylic resin by radical copolymerization reaction to form hybrid resin particles, both of which are highly uniform It has been found that mixed resin particles contained in the properties can be obtained. It has also been found that a polymerized toner in which the polyester resin and the styrene-acrylic resin are present with high uniformity can be easily prepared by aggregating the hybrid resin particles together with the colorant particles in an aqueous medium.

According to the method for producing a toner of the present invention, the polyester resin and the styrene-acrylic resin can be synthesized by polycondensation and radical copolymerization in an aqueous medium in the polymerization step. Can be easily produced in such a manner that toners are contained with high uniformity.
That is, in the polymerization step, in oil droplets formed in an aqueous medium containing a surfactant having a specific acidic group, a divalent or higher carboxylic acid and a divalent or higher alcohol that are raw materials for the polyester resin are: Polycondensation is performed without adding a specific polymerization initiator or a specific catalyst, and styrene compounds and (meth) acrylic acid ester compounds that are raw materials for styrene-acrylic resins are supplied by appropriate polymerization initiators. By performing radical copolymerization, it is possible to easily prepare hybrid resin particles in which both polyester resin and styrene-acrylic resin are mixed with high uniformity.

  In the toner production method of the present invention, as the polycondensable monomer for obtaining a polyester resin, a monomer containing at least one trivalent or higher carboxylic acid or trivalent or higher alcohol is used. A polyester resin having a crosslinked structure can be obtained in the polycondensation step of the polymerization step, and therefore a toner containing the polyester resin having a crosslinked structure can be easily produced.

  Furthermore, in the toner production method of the present invention, the polymerization step and the aggregation step are transferred to a reaction vessel by performing the aggregation step for aggregating the hybrid resin particles in an aqueous medium in which oil droplets are formed in the polymerization step. Therefore, the toner can be manufactured more easily.

  According to the toner of the present invention, since the toner particles constituting the toner particles are colored particles containing mixed resin particles made of a polyester resin and a styrene-acrylic resin, basically, the polyester resin is excellent. The occurrence of the fixing offset phenomenon is reduced by the viscoelasticity, so that the fixing property to the transfer material is obtained, and the excellent low temperature fixing property by the styrene-acrylic resin is obtained. Since it is obtained through a polymerization step, toner particles having a small particle size, no variation among particles, and a sharp charge amount distribution are obtained, and excellent fixability to a transfer material is realized. Excellent fine line reproducibility is realized for the formed image, and as a result, a high-quality image can be stably formed over a long period of time.

  According to the image forming method of the present invention, since the toner is used, a high-quality image can be stably formed over a long period of time.

  The toner of the present invention is a polymerized toner obtained by a toner production method described in detail below, and mixed resin particles containing both a polyester resin and a styrene-acrylic resin, if necessary, colorant particles, etc. The toner particles are composed of colored particles that are aggregated together.

<Toner production method>
The toner production method of the present invention is at least in an aqueous medium containing a surfactant comprising a compound having a long-chain hydrocarbon group and an acidic group (hereinafter also referred to as “acidic group-containing surfactant”). A polycondensable monomer comprising one kind of divalent or higher carboxylic acid (hereinafter referred to as “polyhydric carboxylic acid”) and at least one kind of divalent or higher alcohol (hereinafter referred to as “polyhydric alcohol”). And oil droplets of a composition for forming hybrid resin particles containing a radically polymerizable monomer comprising at least one styrene compound and at least one (meth) acrylate compound, Polycondensation step of polycondensation of polycarboxylic acid and polyhydric alcohol to obtain polyester resin, and radical copolymerization of radical polymerizable monomer to styrene-acrylic It has a polymerization step of obtaining the composite resin particles by performing radical copolymerization to obtain a resin, and aggregation to obtain a colored particles and at least the hybrid resin particles colorant particles are aggregated in an aqueous medium.

As an example of a method for producing such a toner,
(1) For the formation of hybrid resin particles by mixing a polycondensable monomer containing a polyvalent carboxylic acid and a polyhydric alcohol, and a radical polymerizable monomer containing a styrene compound and a (meth) acrylic ester compound An oil droplet forming step of preparing a composition and dispersing the composite resin particle-forming composition in an aqueous medium containing an acidic group-containing surfactant;
(2) a polymerization step of preparing a dispersion of hybrid resin particles by polymerizing an aqueous dispersion of the resulting composite resin particle forming composition;
(3) Aggregation step of obtaining colored particles by agglomerating and fusing the obtained mixed resin particles, colorant particles and, if necessary, toner constituent particles such as wax particles and charge control agent particles in an aqueous medium. ,
(4) A filtration / washing step of filtering the obtained colored particles from an aqueous medium and washing away the surfactant from the colored particles;
(5) The method comprised from the drying process of the washing | cleaning process colored particle is mentioned,
(6) An external additive addition step of adding an external additive to the dried colored particles may be added.
The toner particles constituting the toner refer to particles obtained by adding an external additive to colored particles when an external additive is added, and the colored particles themselves when no external additive is added.

(1) oil droplet forming step;
In the composite resin particle forming composition containing a polycarboxylic acid, a polyhydric alcohol, a styrene compound and a (meth) acrylic ester compound, an acidic group-containing surfactant having a concentration equal to or lower than the critical micelle concentration was dissolved. It is added to an aqueous medium and dispersed using mechanical energy to form oil droplets.

Here, the disperser for dispersing oil droplets by mechanical energy is not particularly limited. For example, a stirring device “CLEARMIX” equipped with a rotor that rotates at high speed (CLEARMIX) (M Technique Co., Ltd.) )), An ultrasonic disperser, a mechanical homogenizer, a manton gourin, a pressure homogenizer, and the like.
Moreover, it is preferable that the number average primary particle diameter of an oil droplet is 50-500 nm in the disperse | distributed state, More preferably, it is 70-300 nm.

  The “aqueous medium” in the present invention refers to a medium containing at least 50% by mass 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, it is preferable to use an organic organic solvent such as methanol, ethanol, isopropanol, and butanol, which is an organic solvent that does not dissolve the resin.

[Acid group-containing surfactant]
The acidic group-containing surfactant used in the toner production method of the present invention is a compound having a hydrophobic group comprising a long-chain hydrocarbon group and a hydrophilic group comprising an acidic group.
Here, the “long-chain hydrocarbon group” refers to a hydrocarbon group having a main chain having 8 or more carbon atoms, and the long-chain hydrocarbon group includes, for example, a main-chain hydrocarbon group. Examples thereof include an alkyl group having 8 to 40 carbon atoms and an aromatic hydrocarbon group which may have an alkyl group as a substituent, preferably a phenyl group having an alkyl group having 8 to 30 carbon atoms in the main chain. Can be mentioned.

As the acidic group constituting the acidic group-containing surfactant, those having high acidity are preferable, and examples thereof include a sulfonic acid group, a carboxylic acid group, and a phosphoric acid group. Among these, a sulfonic acid group is preferable.
Specific preferred examples of the acidic group-containing surfactant include sulfonic acid, carboxylic acid and phosphoric acid having a long-chain hydrocarbon group. Specific examples include dodecyl sulfonic acid, eicosyl sulfonic acid, decyl benzene sulfonic acid, sulfonic acids such as dodecyl benzene sulfonic acid and eicosyl benzene sulfonic acid, carboxylic acids such as dodecyl carboxylic acid, dodecyl phosphoric acid, eicosyl phosphoric acid, etc. In particular, the sulfonic acid compounds are preferred.

  The acidic group-containing surfactant can have an acidic group and a long-chain hydrocarbon group bonded via various inorganic groups or organic groups, but the acidic group and the long-chain hydrocarbon group are directly bonded. It is preferable that they are bonded. The reason for this is not clear, but it is a structure in which a long-chain hydrocarbon group that is a hydrophobic group and an acidic group that is a hydrophilic group are directly connected to each other, making it acidic to an aqueous medium (aqueous phase) in an aqueous medium. Water that is produced in the polycondensation reaction is realized by reliably realizing the state in which the groups are oriented and the hydrophobic groups are oriented to the oil droplets (oil phase) comprising the composition for forming the hybrid resin particles. Is estimated to be effectively discharged into the water phase.

It is preferable that the acidic group-containing surfactant is contained in an amount that gives a concentration equal to or lower than the critical micelle concentration in the aqueous medium. By containing the amount of the acidic group-containing surfactant in the aqueous medium at a concentration equal to or lower than the critical micelle concentration, oil droplets can be stably formed without forming micelles in the aqueous medium. In addition, since there is no excess surfactant, it is expected that all surfactants are properly oriented around the oil droplets when stable oil droplets are formed. It is presumed that the proper orientation state can reliably exert the function as a catalyst related to the dehydration of the polycondensation reaction in the polymerization step described in detail in (2) below, and can increase the reaction rate of the polycondensation reaction. Is done.
Specifically, the acidic group-containing surfactant may be a critical micelle concentration or less in an aqueous medium, specifically 80% or less, more preferably 70% or less of the critical micelle concentration, but is limited. It is not something. The lower limit of the content of the acidic group-containing surfactant is only required to exert a catalyst action in the polycondensation reaction for obtaining the polyester resin. When this lower limit is included, the acidic group-containing surfactant is included. More specifically, the content of is 0.01 to 2 mass%, more preferably 0.1 to 1.5 mass% in the aqueous medium.

  An appropriate anionic surfactant or nonionic surfactant may be contained in the aqueous medium in order to stabilize oil droplets made of the composite resin particle forming composition.

[Polycarboxylic acid]
The polycondensable monomer polycarboxylic acid contained in the composite resin particle forming composition used in the toner production method of the present invention is a divalent or higher carboxylic acid, such as oxalic acid or malon. Acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, iso Dicarboxylic acids such as dodecyl succinic acid, isododecenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid; trimellitic acid, pyro Examples include merit acids, acid anhydrides, or trivalent or higher carboxylic acids such as acid chlorides. Can.
The polyvalent carboxylic acid can be used alone or in combination of two or more.

When trivalent or higher carboxylic acids are used as the polyvalent carboxylic acid, hybrid resin particles having a crosslinked structure can be obtained in the polymerization step.
The proportion of the trivalent or higher carboxylic acid is preferably 0.1% by mass to 10% by mass based on the whole polyvalent carboxylic acid.

[Polyhydric alcohol]
The polycondensable monomer polyhydric alcohol contained in the composite resin particle forming composition used in the toner production method of the present invention is a dihydric or higher alcohol, such as ethylene glycol, diethylene glycol, Ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,4-butylenediol, neopentyl glycol, 1,5-pentane glycol, 1,6-hexane glycol, 1 , 7-heptane glycol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, pinacol, cyclopentane-1,2-diol, cyclohexane-1,4-diol, cyclohexane-1, 2-diol, cyclohexane-1,4-dimethanol, dipropylene Diols such as glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, bisphenol Z, hydrogenated bisphenol A; glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, trisphenol PA, phenol novolac, Examples thereof include trivalent or higher polyhydric aliphatic alcohols such as cresol novolak; alkylene oxide adducts of the above trivalent or higher polyhydric aliphatic alcohols.
A polyhydric alcohol can be used 1 type or in combination of 2 or more types.

When a trivalent or higher polyhydric aliphatic alcohol or an alkylene oxide adduct thereof is used as the polyhydric alcohol, hybrid resin particles having a crosslinked structure can be obtained in the polymerization step.
The proportion of trihydric or higher polyhydric aliphatic alcohols or alkylene oxide adducts thereof used is preferably 0.1% by mass to 10% by mass with respect to the whole polyhydric alcohol.

The ratio between the polyhydric alcohol and the polycarboxylic acid in the polycondensable monomer is the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] of the polyhydric alcohol and the carboxyl group [COOH] of the polycarboxylic acid. However, it is preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2.
When the ratio between the polyhydric alcohol and the polyvalent carboxylic acid is in the above range, a polyester resin having a desired molecular weight can be obtained with certainty.

  The polycondensable monomer of the composite resin particle forming composition can contain a very small amount of a monovalent carboxylic acid and / or a monovalent alcohol together with a polyvalent carboxylic acid and a polyhydric alcohol. Such a monovalent carboxylic acid and a monovalent alcohol act as a polymerization terminator in the polycondensation reaction in oil droplets, and the molecular weight of the polyester resin obtained can be adjusted by the addition amount thereof.

  In the method for producing a toner of the present invention, the content of the polycondensable monomer is preferably 10 to 90% by mass, more preferably 20 to 80% by mass in the entire composition for forming hybrid resin particles. . If the content of the polycondensable monomer is too small, the resulting toner may not exhibit sufficient viscoelasticity due to the polyester resin component, resulting in insufficient fixability, and fixing offset may occur. is there. In addition, when the content of the polycondensable monomer is excessive, the low-temperature fixability due to the styrene-acrylic resin component described later is not sufficiently exhibited in the obtained toner, and the fixability is reduced. There is a risk.

[Styrene compound]
Examples of the radical polymerizable monomer styrene compound contained in the composite resin particle forming composition used in the toner production method of the present invention include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, p- Styrene monomers or styrene derivatives such as n-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, and the like may be used, and these may be used alone or in combination of two or more. Can be used.
The content of the styrene compound is not particularly limited. From the viewpoint of adjusting the softening point temperature and the glass transition temperature of the styrene-acrylic resin, generally, the radical polymerizable monomer is preferably 40 to It is 95 mass%, More preferably, it is 50-80 mass%.

[(Meth) acrylic acid ester compound]
Examples of the radically polymerizable monomer (meth) acrylic acid ester compound contained in the composite resin particle forming composition used in the method for producing a toner of the present invention include methyl methacrylate, ethyl methacrylate, and n-methacrylic acid. Butyl, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate Methacrylic acid ester derivatives such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethyl acrylate Hexyl, stearyl acrylate, lauryl acrylate, include the acrylic acid ester derivative such as phenyl acrylate, These can be used alone or in combination.
The content of the (meth) acrylic acid ester compound is not particularly limited. From the viewpoint of adjusting the softening point temperature and the glass transition temperature of the styrene-acrylic resin, generally, the radical polymerizable monomer as a whole. Is preferably 5 to 60% by mass, and more preferably 10 to 50% by mass.

  Further, the radical polymerizable monomer may contain a compound having an ionic dissociation group. Examples of the compound having an ionic dissociation group include a substituent such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group as a constituent group of the monomer. Specifically, acrylic acid, methacrylic acid, Maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, acid phosphooxyethyl And methacrylate and 3-chloro-2-acid phosphooxypropyl methacrylate.

Furthermore, the radical polymerizable monomer may contain a polyfunctional vinyl compound. Examples of this polyfunctional vinyl compound include divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl. The compound which has 2 or more unsaturated bonds, such as glycol diacrylate, is mentioned, These can be used 1 type or in combination of 2 or more types. When the radical polymerizable monomer contains a polyfunctional vinyl compound, a styrene-acrylic resin having a crosslinked structure can be obtained in the radical copolymerization step of the polymerization step.
The content of the polyfunctional vinyl compound can be selected according to the elasticity required in the obtained styrene-acrylic resin, and is generally 0.01 to It is preferable that it is 10 mass%, More preferably, it is 0.02-5 mass%. When the content of the polyfunctional vinyl compound is excessive, the resulting styrene-acrylic resin has a high cross-linking rate and an excessively high softening point temperature, so that the obtained toner has a fixing property. May be reduced. Moreover, when content of a polyfunctional vinyl compound is too small, a crosslinked structure part cannot fully be obtained and the effect by bridge | crosslinking cannot fully be exhibited.

The composite resin particle forming composition used in the method for producing a toner of the present invention contains a polymerization initiator in order to generate radicals in oil droplets that initiate a radical copolymerization reaction in a polymerization step described later. There may be.
As such a polymerization initiator, an oil-soluble polymerization initiator can be used, and as an oil-soluble polymerization initiator, for example, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyro Azo or diazo polymerization initiators such as nitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2 Examples include peroxide polymerization initiators such as -bis- (4,4-t-butylperoxycyclohexyl) propane and tris- (t-butylperoxy) triazine, and polymer initiators having a peroxide in the side chain. be able to.

In addition to containing an oil-soluble polymerization initiator in the oil droplets, a water-soluble polymerization initiator is contained in the aqueous medium to generate radicals in the oil droplets to start the radical copolymerization reaction and the aqueous system. It can also be set as the structure made to produce | generate in a medium and to supply to an oil droplet.
Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and salts thereof, and hydrogen peroxide.
In addition, the oil droplets do not contain a polymerization initiator, only a water-soluble polymerization initiator is contained in the aqueous medium, and radicals that initiate radical copolymerization reaction are generated only in the aqueous medium and supplied to the oil droplets. It can also be set as the structure to make.

  In the method for producing the toner of the present invention, the content of the radical copolymerizable monomer is preferably 10 to 90% by mass, more preferably 20 to 80% by mass in the entire composite resin particle forming composition. If the content of the radical copolymerizable monomer is too small, there is a risk that the low temperature fixability by the styrene-acrylic resin component may not be sufficiently obtained, and the content of the radical copolymerizable monomer is excessive. In this case, the viscoelasticity due to the polyester resin component may not be sufficiently exhibited, and fixing offset may occur.

〔Organic solvent〕
The composite resin particle forming composition used in the toner production method of the present invention may contain various oil-soluble components such as organic solvents. Examples of such an organic solvent include those having a low boiling point and low solubility in water, such as toluene and ethyl acetate.

  Further, the composite resin particle forming composition used in the method for producing a toner of the present invention may contain a colorant or a wax. By carrying out the polymerization step using such a composition for forming mixed resin particles containing a colorant or wax, it is possible to obtain hybrid resin particles that are pre-colored or pre-containing wax. The content of the wax is 2 to 20% by mass, preferably 3 to 18% by mass, and more preferably 2 to 15% by mass in the entire composition for forming hybrid resin particles.

(2) polymerization step;
In the polymerization step, in the oil droplets dispersed in the aqueous medium in the oil droplet formation step, a polycondensation step in which a polyvalent carboxylic acid and a polyhydric alcohol are polycondensed to obtain a polyester resin, a styrene compound and (meta ) A radical copolymerization step is carried out in which an acrylic ester compound is radically copolymerized to obtain a styrene-acrylic resin, thereby obtaining hybrid resin particles in which a polyester resin and a styrene-acrylic resin are mixed with high uniformity. .

(2-1) polycondensation step;
In this polycondensation step, the acidic group-containing surfactant is oriented on the surface of the formed oil droplets with the hydrophilic group consisting of acidic groups in the aqueous phase and the hydrophobic group consisting of long-chain hydrocarbon groups oriented in the oil phase. The acidic groups present at the interface between the oil droplets and the aqueous phase exert the catalytic effect of dehydration, and the water generated in the polycondensation is removed from the oil droplets. It is estimated that the polycondensation reaction accompanied by dehydration proceeds in the existing oil droplets.

  The polymerization temperature for performing polycondensation is usually 40 ° C. or higher, preferably 50 to 150 ° C., although it depends on the type of polyvalent carboxylic acid and polyhydric alcohol contained in the composite resin particle forming composition. It is more preferable that it is 50-100 degreeC from the objective made into the boiling point or less of water in. Moreover, although superposition | polymerization reaction time is based also on the reaction rate of the polycondensation which forms a hybrid resin particle, it is 4 to 10 hours normally.

The polyester resin obtained in the polycondensation step has a molecular weight measured by gel permeation chromatography (GPC) of 10,000 or more, preferably 20,000 to 10,000,000, more preferably in terms of weight average molecular weight (Mw). Is preferably 30,000 to 1,000,000. When the weight average molecular weight is less than 10,000, an offset phenomenon may occur at a high temperature in the fixing process of the image forming operation using the toner.
Moreover, this polyester resin has a molecular weight measured by GPC of 20,000 or less, preferably 1,000 to 10,000, more preferably 2,000 to 8,000 in terms of number average molecular weight (Mn). When the number average molecular weight exceeds 20,000, low-temperature fixability in the fixing process of image formation using the toner, and desired glossiness cannot be obtained for an image obtained by image formation when a color toner is used. There is a fear.

  The polyester resin preferably has a glass transition temperature of 20 to 90 ° C and a softening temperature of 80 to 220 ° C, a glass transition temperature of 35 to 65 ° C, and a softening temperature of 80 to 150 ° C. More preferably it is. The glass transition temperature is measured by the onset method at the time of the second temperature increase in the differential calorimetric analysis method, and the softening point temperature can be measured by the half method of the Koka type flow tester.

(2-2) radical copolymerization step;
In this radical copolymerization step, in the formed oil droplets, radicals are generated by the polymerization initiator contained in the oil droplets and / or radicals generated by the polymerization initiator contained in the aqueous medium. Is supplied to the oil droplets to initiate a radical copolymerization reaction.

  The polymerization temperature at which radical copolymerization is carried out depends on the type of styrene compound and (meth) acrylic acid ester compound contained in the composition for forming hybrid resin particles, and the type of polymerization initiator that generates radicals. It is -100 degreeC, Preferably it is 55-90 degreeC, More preferably, it is 3-20 degreeC. Moreover, although superposition | polymerization reaction time is based also on the reaction rate of the radical copolymerization which synthesize | combines a styrene-acrylic-type resin, it is 5 to 12 hours normally.

The styrene-acrylic resin obtained in the radical copolymerization step preferably has a molecular weight measured by gel permeation chromatography (GPC) of 2,000 to 1,000,000 in terms of weight average molecular weight (Mw). The molecular weight measured by GPC is preferably 1,000 to 100,000 in terms of number average molecular weight (Mn). The molecular weight distribution (Mw / Mn) is preferably 1.5 to 100, particularly 1.8 to 70. When the weight average molecular weight (Mw), the number average molecular weight (Mn), and the molecular weight distribution (Mw / Mn) are within the above ranges, the occurrence of an offset phenomenon is suppressed in the fixing process of the image forming operation using the obtained toner. be able to.
The styrene-acrylic resin obtained in the radical copolymerization step preferably has a glass transition temperature of 30 to 70 ° C, and preferably has a softening temperature of 80 to 170 ° C. When the glass transition point temperature and the softening point temperature are in the above ranges, good fixability can be obtained.

In the above polymerization process, for example, it is preferable to start a radical copolymerization reaction in the presence of a polyester resin after first performing a polycondensation reaction and finishing it.
After completing the radical copolymerization reaction of the radical copolymerization step, the polycondensation reaction of the polycondensation step can be performed in the presence of a styrene-acrylic resin, or the polycondensation reaction and the radical copolymerization reaction can be started simultaneously. For example, the presence of a styrene-acrylic resin by a radical copolymerization reaction is not preferable because the polycondensation reaction between the polyvalent carboxylic acid and the polyhydric alcohol may be inhibited.

(3) agglomeration step;
In the agglomeration step, a dispersion of mixed resin particles obtained by the polymerization step (2) above, and a dispersion of colorant particles and, if necessary, wax particles, charge control agent particles, and other toner component particles are used. A dispersion liquid for aggregation is prepared by mixing, and mixed resin particles and colorant particles are aggregated in an aqueous medium and fused to form a dispersion of colored particles.

Specifically, a coagulant having a critical coagulation concentration or higher is added to the dispersion for coagulation and salted out, and at the same time, the agitation mechanism is agitated in a reaction apparatus (see FIG. 1) which is an agitating blade described later to constitute the hybrid resin particles. The polyester resin and the styrene-acrylic resin are heated and fused at a temperature equal to or higher than the glass transition temperature to gradually grow the particle size while forming agglomerated particles. The diameter growth is stopped, and further, the particle surface is smoothed while heating and stirring to control the shape to form colored particles.
In addition, you may add the organic solvent which melt | dissolves infinitely with respect to water simultaneously with a coagulant | flocculant here in the dispersion liquid for aggregation. Further, for example, an agglomeration aid composed of slaked lime, soda ash, bentonite, fly ash, kaolin and the like can be used.

〔wax〕
As the wax constituting the wax particles, for example, low molecular weight polyethylene wax, low molecular weight polypropylene wax, Fischer-Tropsch wax, microcrystalline wax, hydrocarbon wax such as paraffin wax, carnauba wax, pentaerythritol behenate, Examples thereof include ester waxes such as behenyl citrate, and these can be used alone or in combination of two or more.

  The content ratio of the wax is 2 to 20% by mass, preferably 3 to 18%, more preferably 4 to 15% by mass in the whole toner.

Although it does not specifically limit as a flocculant, The thing selected from the salt of a metal is used suitably.
Specifically, monovalent metal salts such as alkali metal salts such as sodium, potassium and lithium, for example, divalent metal salts such as calcium, magnesium, manganese and copper, and trivalent such as iron and aluminum Examples of specific salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Of these, divalent metal salts are particularly preferred. When a divalent metal salt is used, agglomeration can be promoted with a smaller amount. These may be used alone or in combination of two or more.

The addition amount of the flocculant to the dispersion for aggregation is preferably not less than the critical aggregation concentration, more preferably not less than 1.2 times the critical aggregation concentration, and still more preferably not less than 1.5 times the critical aggregation concentration. .
Here, the “critical flocculation concentration” is an index relating to the stability of the aqueous dispersion, and indicates a concentration at which flocculation occurs when a flocculant is added. This critical agglomeration concentration varies greatly depending on the dispersed particle components and the like. For example, a detailed critical aggregation concentration can be obtained by a technique described in Seizo Okamura et al., “Polymer Chemistry 17,601 (1960) edited by Japan Society of Polymer Science”. Another method is to add the desired salt to the target flocculation dispersion at a different concentration, measure the ξ (zeta) potential of the flocculation dispersion, and determine the critical salt concentration at which this value changes. It can also be determined as the aggregation concentration.

As the organic solvent that is infinitely soluble in water, a solvent that does not dissolve the formed polyester resin is selected. Specifically, methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, glycerin, acetone, and the like are used. Examples thereof include methanol, ethanol, 1-propanol and 2-propanol alcohol having 3 or less carbon atoms, and 2-propanol is particularly preferable.
The addition amount of the organic solvent that is infinitely soluble in water is preferably 1 to 100% by volume with respect to the flocculation dispersion liquid to which a flocculant is added.

  In the flocculation step, it is preferable that the standing time (time until heating is started) to be left after adding the flocculant is as short as possible. That is, after adding the flocculant, it is preferable to start heating the flocculation dispersion as quickly as possible so that the temperature is equal to or higher than the glass transition temperature of the hybrid resin particles. The reason for this is not clear, but the agglomeration state of the particles fluctuates with the passage of the standing time, and there is a possibility that the particle size distribution of the obtained toner particles becomes unstable or the surface property fluctuates. Because there is. The standing time is usually within 30 minutes, preferably within 10 minutes. The temperature at which the flocculant is added is not particularly limited, but is preferably equal to or lower than the glass transition temperature of the polyester resin and styrene-acrylic resin constituting the hybrid resin particles.

  In the aggregation step, it is preferable to quickly raise the temperature by heating, and the rate of temperature rise is preferably 1 ° C./min or more. The upper limit of the heating rate is not particularly limited, but is preferably 15 ° C./min or less from the viewpoint of suppressing the generation of coarse particles due to rapid progress of fusion. Furthermore, it is important to continue the fusion by holding the temperature of the aggregation dispersion liquid for a certain period of time after the aggregation dispersion liquid reaches a temperature equal to or higher than the glass transition temperature. Thereby, the growth of the colored particles (aggregation of the hybrid resin particles and the colorant particles) and the fusion (disappearance of the interface between the particles) can be effectively advanced, and the durability of the finally obtained toner particles Can be improved.

[Colorant]
A dispersion of colorant particles can be prepared by dispersing a colorant in an aqueous medium. The dispersion treatment of the colorant is preferably performed in a state where the surfactant concentration in the aqueous medium is equal to or higher than the critical micelle concentration because the colorant is uniformly dispersed. Although the disperser used for the dispersion | distribution process of a coloring agent is not specifically limited, What was used in the oil droplet formation process of said (1) can be mentioned. Moreover, it is although it does not specifically limit as surfactant which can be used, The following anionic surfactant can be mentioned as an example of a suitable thing.

  Examples of the anionic surfactant include sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate, sodium arylalkyl polyether sulfonate, 3,3-disulfone diphenylurea-4,4-diazo-bis-amino-8-naphthol- Sulfonates such as sodium 6-sulfonate, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sulfonate; sodium dodecyl sulfate, tetradecyl sulfate Sulfates such as sodium, sodium pentadecyl sulfate, sodium octyl sulfate; sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, potassium oleate Fatty acid salts such as um and the like.

  As the colorant to be used, carbon black, magnetic substance, dye, pigment, etc. can be arbitrarily used, and as channel black, furnace black, acetylene black, thermal black, lamp black, etc. are used as carbon black. . Magnetic materials include ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example, a kind of alloy called Heusler alloy such as manganese-copper-aluminum and manganese-copper-tin, chromium dioxide, and the like can be used.

  As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95, etc. can be used, and mixtures thereof can also be used. Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, 185, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 60, etc. can be used, and a mixture thereof can also be used. The number average primary particle diameter varies depending on the type, but is preferably about 10 to 200 nm.

As the charge control agent constituting the charge control agent particles, various known ones that can be dispersed in an aqueous medium can be used. Specific examples include nigrosine dyes, naphthenic acid or higher fatty acid metal salts, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, salicylic acid metal salts or metal complexes thereof.
The charge control agent particles preferably have a number average primary particle diameter of about 10 to 500 nm in a dispersed state.

[Reactor]
In the toner composed of toner particles composed of colored particles obtained by agglomerating and fusing the hybrid resin particles, the flow in the reactor is a laminar flow, and the agitation blade and the agitation can be made uniform in the internal temperature distribution By using the tank and controlling the temperature, the number of rotations, and the time in the aggregation process, it is possible to have a desired shape factor and a highly uniform shape distribution. The reason why a toner having a highly uniform shape distribution can be obtained is that when an agglomeration step is performed in a place where a laminar flow is formed, strong stress is not applied to the agglomerated particles in which aggregation and fusion progress, and In the laminar flow in which the flow is accelerated, it is presumed that the shape distribution of the aggregated particles becomes uniform as a result of the uniform temperature distribution in the stirring tank. Furthermore, by performing the shape control step by heating and stirring, the aggregated particles gradually become spherical, and the shape of the obtained colored particles can be arbitrarily controlled.

As a stirrer blade and a stirrer used for producing toner composed of toner particles made of colored particles obtained by agglomerating and fusing the hybrid resin particles, for example, the one shown in FIG. Can be mentioned.
This reactor is equipped with a multistage stirrer blade in which an upper stirrer blade is disposed with a crossing angle α preceding the lower stirrer blade in the rotational direction. It has a feature that an obstacle such as a baffle that forms a flow is not provided.

In the reaction apparatus shown in FIG. 1, a rotating shaft 3 is vertically suspended from a central portion of a vertical cylindrical stirring tank 2 having a heat exchange jacket 1 attached to the outer periphery thereof. The stirring blade 4b located in the lower stage close | similar to the bottom face of this and the stirring blade 4a located in the upper stage are provided. The upper stirring blade 4a has a crossing angle α preceding the stirring blade 4b positioned in the lower stage in the rotational direction.
In FIG. 1, the arrows indicate the direction of rotation, 7 is an upper material inlet, and 8 is a lower material inlet.

In the toner production method of the present invention, the crossing angle α of the stirring blades 4a and 4b is preferably less than 90 °. The lower limit of the crossing angle α is not particularly limited, but is preferably 5 ° or more and less than 90 °, more preferably 10 ° or more and less than 90 °.
By setting it as such a structure, the dispersion liquid for aggregation is first stirred by the stirring blade 4a arrange | positioned at the upper stage, and the flow to the lower side is formed. Next, the flow formed by the upper stirring blade 4a is further accelerated downward by the stirring blade 4b disposed in the lower stage, and a downward flow is separately formed in the stirring blade 4a itself, and the flow as a whole is increased. Presumed to be accelerated and proceed.

The shape of the stirring blade is not particularly limited as long as it does not form a turbulent flow, but is formed from a continuous plate having no through-hole or the like, such as the rectangular plate shown in FIG. Those are preferable, and may have a curved surface.
Since the stirring blade does not form a turbulent flow, coalescence of the hybrid resin particles does not occur in the polymerization process, and further, redispersion due to the destruction of the hybrid resin particles does not occur. Further, in the aggregation process, excessive collision between the aggregated particles can be suppressed, and the uniformity of the particle size distribution can be improved. Therefore, a toner having a uniform particle size distribution can be obtained. Furthermore, since excessive coalescence of particles can be suppressed, a toner having a uniform shape can be obtained.

(4) Filtration and washing process;
In this filtration / washing step, a filtration treatment for filtering out the colored particles from the dispersion of colored particles obtained in the aggregating step, and a surfactant or the like from the filtered colored particles (cake-like aggregate). A cleaning process for removing deposits such as an aggregating agent is performed. Here, examples of the filtration method include a centrifugal separation method, a vacuum filtration method using Nutsche and the like, a filtration method using a filter press and the like, and are not particularly limited.

(5) drying step;
In this drying step, the washed colored particles are subjected to a drying process. Examples of the dryer used in the drying step include a spray dryer, a vacuum freeze dryer, and a vacuum dryer. The water content of the dried colored particles is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less.

  Here, the water content of the colored particles can be measured by the Karl Fischer method. Specifically, using a moisture content measuring apparatus “AQS-724” (manufactured by Hiranuma Sangyo Co., Ltd.) under the conditions of a sample humidity adjustment environment condition of a temperature of 30 ° C., a humidity of 85% RH, and a sample heating condition of 110 ° C. The water content measured in the colored particles left for 24 hours in a high-temperature and high-humidity environment with a humidity of 85% RH was defined as the water content of the colored particles.

  Further, when the dried colored particles are aggregated by weak interparticle attractive force to form an aggregate, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.

(6) External additive addition step;
This external additive adding step is a step of adding an external additive to the dried colored particles for the purpose of improving fluidity, chargeability and cleaning property. Examples of the apparatus used for adding the external additive include various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer.

The external additive is not particularly limited, and various inorganic fine particles, organic fine particles, lubricants and the like can be used. As the inorganic fine particles, inorganic oxide particles such as silica, titania, and alumina are preferably used, and these inorganic fine particles are preferably hydrophobized with a silane coupling agent or a titanium coupling agent.
The degree of the hydrophobizing treatment is not particularly limited, but a methanol wettability of 40 to 95 is preferable. Methanol wettability is an evaluation of wettability to methanol. In this method, 0.2 g of inorganic fine particles to be measured is weighed and added to 50 ml of distilled water in a 200 ml beaker. Methanol is slowly added dropwise from a burette, the tip of which is immersed in a liquid, with slow stirring until the entire inorganic fine particles are wet. When the amount of methanol necessary to completely wet the inorganic fine particles is a (ml), the degree of hydrophobicity is calculated by the following formula 1.
(Formula 1) Degree of hydrophobicity = {a / (a + 50)} × 100

  The amount of the external additive added is 0.1 to 5.0% by mass in the toner, preferably 0.5 to 4.0% by mass. In addition, various external additives may be used in combination.

[Toner shape factor]
In the toner obtained by the above manufacturing method, the ratio of the toner particles having a shape factor in the range of 1.0 to 1.6 is preferably 65% by number or more, and 70% by number or more. Is more preferable. When the ratio of the toner particles having the shape factor in the range of 1.0 to 1.6 is 65% by number or more, the density of toner particles in the toner layer transferred to the transfer material is increased, and the fixing property is improved. The offset is less likely to occur. In addition, the toner particles are less likely to be crushed, the contamination of the charging member is reduced, and the chargeability of the toner is stabilized.

The toner shape factor is calculated by the following equation 2 and indicates the degree of roundness of the toner particles.
(Formula 2) Shape factor = {(maximum diameter / 2) ² × π} / projection area

  Here, the maximum diameter refers to the width of a particle that maximizes the interval between the parallel lines when a projected image of toner particles on a plane is sandwiched between two parallel lines. The projected area refers to the area of the projected image of the toner particles on the plane. Here, this shape factor is obtained by taking a photograph in which toner particles are enlarged 2000 times with a scanning electron microscope, and then analyzing the photographic image using “SCANNINGIMAGEANALYZER” (manufactured by JEOL Ltd.) based on this photograph. Measured by performing. At this time, the shape factor was calculated by the above equation 2 using 100 toner particles.

  The method for controlling the shape factor is not particularly limited, and for example, a method of heating and stirring while applying a swirling flow by a reaction apparatus following the aggregation step (3) can be used.

[Variation coefficient of toner shape factor]
Further, in the toner obtained by the manufacturing method as described above, the variation coefficient of the shape factor is preferably 16% or less, and more preferably 14% or less. When the variation coefficient of the shape factor is 16% or less, voids in the transferred toner layer (powder layer) are reduced, fixing property is improved, and fixing offset is hardly generated. Further, since the charge amount distribution becomes sharp, the transfer efficiency is increased and the image quality is improved.

The variation coefficient of the shape factor of the toner is calculated by the following formula 3.
(Equation 3) Variation coefficient = (S ₁ / K) × 100

In Equation 3, S ₁ represents the standard deviation of the shape factor of 100 toner particles, and K represents the average value of the shape factor.

  In order to uniformly control the shape factor of the toner and the variation coefficient of the shape factor without any variation in lots, it is possible to determine an appropriate process end time while monitoring the characteristics of the aggregated particles being formed in the aggregation process. Good. Monitoring means that a measuring device is incorporated in-line, and process conditions are controlled based on the measurement result. In other words, the shape and the like are incorporated in-line, the shape and particle size are measured while sequentially sampling in the aggregation process, and the reaction is stopped when the desired shape is obtained. Although it does not specifically limit as a monitoring method, Flow type particle image analyzer "FPIA-2000" (made by Sysmex Corporation) can be used. This apparatus is suitable because the shape can be monitored by performing image processing in real time while passing the sample liquid. That is, a pump or the like is used from the reaction field and is constantly monitored to measure the shape and the like, and the reaction is stopped when the desired shape is obtained.

[Toner number variation coefficient]
Further, in the toner obtained by the above production method, the number variation coefficient in the number particle size distribution of the toner is preferably 27% or less, and more preferably 25% or less. When the number variation coefficient is 27% or less, voids in the transferred toner layer (powder layer) are reduced, fixing property is improved, and fixing offset hardly occurs. Further, since the charge amount distribution becomes sharp, the transfer efficiency is increased and the image quality is improved.

  The number particle size distribution and the number variation coefficient are measured by Multisizer 3 (manufactured by Beckman Coulter). In the present invention, the multisizer 3 is used and connected to a computer equipped with dedicated software for collecting and processing data. The aperture used in the multisizer 3 was 100 μm, and the volume and number of toners of 2 μm or more were measured to calculate the number particle size distribution and the number average particle size. The number particle size distribution represents the relative frequency of the toner particles with respect to the particle size, and the number average particle size represents the median diameter in the number particle size distribution.

The number variation coefficient in the number particle size distribution of the toner is calculated from Equation 4 below.
(Formula 4) Number variation coefficient = (S ₂ / D _n ) × 100 (%)

In Equation 4, S ₂ represents the standard deviation in the number particle size distribution, and D _n represents the number average particle size (μm).

  The method for controlling the number variation coefficient in the number particle size distribution of the toner is not particularly limited. For example, a method of classifying toner particles by wind force can be used, but classification in a liquid is effective for reducing the number variation coefficient. As a method of classifying in this liquid, there is a method of separating and collecting toner particles according to a difference in sedimentation speed caused by a difference in toner particle diameter by using a centrifuge and controlling the rotation speed.

[Proportion of colored particles without corners]
In the toner obtained by the above production method, the ratio of colored particles having no corners in the colored particles constituting the toner is preferably 50% by number or more, and more preferably 70% by number or more. Further preferred.

  When the ratio of colored particles having no corners is 50% by number or more, voids in the transferred toner layer (powder layer) are reduced, fixing property is improved, and fixing offset is hardly generated. In addition, colored particles that are easily worn and broken and colored particles having a portion where charges are concentrated are reduced, the charge amount distribution becomes sharp, the chargeability is stable, and good image quality can be formed over a long period of time.

  Here, “colored particles having no corners” refers to colored particles that do not substantially have protrusions that concentrate electric charges or protrusions that easily wear due to stress. Specifically, the following colored particles Is called colored particles without corners. That is, as shown in FIG. 2A, when the major axis of the colored particle T is L, it is a circle C having a radius (L / 10) and is one point inside the peripheral line of the projected image of the colored particle T. A case where the circle C does not substantially protrude outside the colored particles T when the inner side is rolled while being in contact with is referred to as “colored particles having no corners”. “A case where the protrusion does not substantially protrude” refers to a case where the protrusion having the protruding circle is one or less. The “major axis of the colored particles” refers to the width of the particle that maximizes the interval between the parallel lines when the projected image of the colored particles on the plane is sandwiched between two parallel lines. 2B and 2C show projected images of colored particles having corners, respectively.

  The ratio of colored particles having no corners is as follows. First, a photograph in which the toner particles are enlarged is taken with a scanning electron microscope, and further enlarged to obtain a 15,000 times photographic image. If it is present, this is ignored, a colored particle image is drawn, the presence or absence of the corner is detected, and this detection operation is performed for 100 toner particles.

  The method for obtaining colored particles having no corners is not particularly limited. For example, there are many irregularities on the surface of the agglomerated particles at the stage where the agglomeration of the mixed resin particles is stopped, and the surface is not smooth. As a result, colored particles having no corners are obtained. These conditions vary depending on the physical properties of the hybrid resin particles.For example, by setting the rotational speed to be higher than the glass transition temperature of the polyester resin and the styrene-acrylic resin constituting the hybrid resin particles, The surface becomes smooth and colored particles having no corners can be formed.

[Particle size of toner particles]
Further, in the toner obtained by the above manufacturing method, the particle diameter of the toner particles is preferably 3 to 8 μm in terms of volume-based median diameter. The particle diameter of the toner particles can be controlled by the concentration of the aggregating agent, the amount of the organic solvent added in the aggregating step, the fusing time, and the composition of the polyester resin. When the volume-based median diameter is 3 to 8 μm, toner particles that have a large adhesion force that fly and adhere to the heating member and generate a fixing offset in the fixing step are reduced, and transfer efficiency is increased and half The image quality of the tone is improved, and the image quality of fine lines and dots is improved.
The volume-based median diameter is measured using “Multisizer 3” (manufactured by Beckman Coulter, Inc.).

<Developer>
The toner of the present invention may be used, for example, as a one-component magnetic toner containing a magnetic material, as a two-component developer mixed with a so-called carrier, or as a non-magnetic toner alone. However, in the present invention, it is preferably used as a two-component developer used by mixing with a carrier.

As the carrier constituting the two-component developer, magnetic particles made of conventionally known materials such as metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead can be used. It is particularly preferable to use ferrite particles.
The carrier preferably has a volume-based median diameter of 15 to 100 μm, more preferably 25 to 60 μm. The volume-based median diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.
As the carrier, it is preferable to use a carrier coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicone resin, ester resin, or fluorine-containing polymer resin is used. Moreover, it does not specifically limit as resin for comprising a resin dispersion type carrier, A well-known thing can be used, For example, a styrene-acrylic resin, a polyester resin, a fluorine resin, a phenol resin etc. are used. be able to.

<Development method>
The developing method in which the toner of the present invention can be used is not particularly limited. It can be suitably used for any system, such as a system using a two-component developer prepared by mixing with a so-called carrier, or a system using a single-component developer consisting only of toner. The toner of the present invention has a sharp charge amount distribution and almost no variation between the toners.

It is preferable to apply an alternating electric field between the developer carrying member and the latent image carrying member in the developing device used. It is preferable that the alternating electric field f is 200 to 8000 Hz and the peak-to-peak voltage V _pp is 500 to 3000 V.

<Image forming method>
The image forming method of the present invention includes a step of developing a latent image formed on a latent image carrier with a developer containing the toner of the present invention, visualizing it, and then transferring the toner to a transfer material.
Specifically, the toner latent image electrostatically formed on the latent image carrier is made manifest by a developer by applying the non-contact developing method and the like to obtain a toner image. The toner image is transferred to a transfer material by applying a transfer electric field, and then the toner image transferred onto the transfer material is fixed on the transfer material by applying a fixing method described later, thereby obtaining a visible image. It is done.

<Fixing method>
As a suitable fixing method using the toner of the present invention, a so-called contact heating method can be mentioned. Examples of the contact heating method include a heat pressure fixing method, a heat roll fixing method, and a pressure contact heat fixing method in which fixing is performed by a rotating pressure member including a fixedly arranged heating body.

In the fixing method of the hot roll fixing method, usually, an upper roller provided with a heat source inside a metal cylinder made of iron or aluminum whose surface is coated with fluororesin, etc., and a lower roller formed of silicone rubber or the like Is used.
As the heat source, a linear heater is used, and the surface temperature of the upper roller is heated to about 120 to 200 ° C. by this heater. A pressure is applied between the upper roller and the lower roller, and the lower roller is deformed by this pressure, so that a so-called nip is formed in the deformed portion. The width of the nip is 1 to 10 mm, preferably 1.5 to 7 mm. The fixing linear velocity is preferably 40 mm / sec to 600 mm / sec. If the nip width is too small, heat cannot be uniformly applied to the toner, and uneven fixing may occur. On the other hand, if the nip width is too large, it is contained in the toner particles. The melting of the polyester resin is accelerated, and there is a possibility that fixing offset occurs.

  The fixing device may be provided with a cleaning mechanism. Examples of the cleaning mechanism include a mechanism for supplying silicone oil to the upper roller or the film member, and a mechanism for cleaning with a pad, roller, or web impregnated with silicone oil. As the silicone oil, polydimethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane, or the like can be used. Furthermore, siloxane containing fluorine can also be suitably used.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to said aspect, A various change can be added.

  EXAMPLES Examples carried out to confirm the effects of the present invention will be described below, but the present invention is not limited to these examples.

<Preparation Example 1 of hybrid resin particles>
240 g of water (acid group-containing interface) containing 2 g of dodecylbenzenesulfonic acid in a state where 32 g (139 mmol) of azelaic acid, 28 g (139 mmol) of 1,10-decanediol, 80 g of styrene and 20 g of butyl acrylate were heated to 95 ° C. The content of the active agent is 0.83% by mass) and dispersed with an ultrasonic disperser to form oil droplets, and then the reaction solution is reacted at 95 ° C. for 24 hours to obtain a polyester resin. The temperature was lowered to 80 ° C., an aqueous solution containing 1.5 g of potassium persulfate was added, radicals were supplied from the aqueous medium and reacted for 5 hours to obtain a styrene-acrylic resin, and the hybrid resin particles (1) Was prepared.
As a result of separating the polyester resin part from the hybrid resin particles and measuring the molecular weight, the weight average molecular weight (Mw) measured by GPC is 20,000, the number average molecular weight (Mn) is 10,000, and the glass transition temperature Tg is The softening point temperature was 60 ° C. and 125 ° C. Further, as a result of measuring the molecular weight of the styrene-acrylic resin portion separated from the hybrid resin particles, the weight average molecular weight (Mw) measured by GPC was 52,000, the number average molecular weight (Mn) was 9,000, and the molecular weight. The distribution (Mw / Mn) was 5.7, the glass transition temperature Tg was 53 ° C., and the softening point temperature was 118 ° C. The size of the hybrid resin particles (1) was 210 nm in terms of number average primary particle size.

<Preparation Example 2 of Hybrid Resin Particle>
22 g (54 mmol) of polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 1.2 g (10 mmol) of neopentyl glycol, 10 g of terephthalic acid and 0.6 g of isophthalic acid (64 mmol in total) , 80 g of styrene and 20 g of 2-ethylhexyl acrylate were heated to 95 ° C. and added to 240 g of water containing 3 g of dodecylbenzenesulfonic acid (content of acidic group-containing surfactant: 1.25% by mass), Oil droplets are formed by dispersing with an ultrasonic disperser, and then this reaction solution is reacted at 98 ° C. for 36 hours to obtain a polyester resin. Thereafter, the temperature is lowered to 80 ° C., and 1.5 g of potassium persulfate A styrene-acrylic resin is added by adding the aqueous solution contained, supplying radicals from the aqueous medium and reacting for 5 hours. Obtained and hybrid resin particles (2) was prepared.
As a result of separating the polyester resin portion from the hybrid resin particles and measuring the molecular weight, the weight average molecular weight (Mw) measured by GPC is 30,000, the number average molecular weight (Mn) is 9,000, and the glass transition temperature Tg is The softening point temperature was 52 ° C. and 117 ° C. Further, as a result of measuring the molecular weight of the styrene-acrylic resin portion separated from the hybrid resin particles, the weight average molecular weight (Mw) measured by GPC was 53,000, the number average molecular weight (Mn) was 8,500, and the molecular weight. The distribution (Mw / Mn) was 6.2, the glass transition temperature Tg was 51 ° C., and the softening point temperature was 114 ° C. The size of the hybrid resin particles (2) was 230 nm in terms of number average primary particle size.

<Preparation Example 3 of Hybrid Resin Particle>
Polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane 22 g (54 mmol), neopentyl glycol 1.2 g (10 mmol), terephthalic acid 9.5 g and isophthalic acid 0.5 g (combined) 60 gm), trimellitic acid 0.5 g (2 mmol), styrene 80 g and butyl acrylate 20 g heated to 95 ° C. and 240 g water containing 3 g dodecylbenzenesulfonic acid (content of acidic group-containing surfactant) 1.25 mass%) and dispersed with an ultrasonic disperser to form oil droplets, and then the reaction solution is reacted at 95 ° C. for 24 hours to obtain a polyester resin, and then heated to 80 ° C. The aqueous solution containing 1.5 g of potassium persulfate was added, radicals were supplied from the aqueous medium and reacted for 5 hours. , Styrene - to obtain an acrylic resin, to prepare a hybrid resin particles (3).
As a result of separating the polyester resin part from the mixed particle particles and measuring the molecular weight, the weight average molecular weight (Mw) measured by GPC is 50,000, the number average molecular weight (Mn) is 5,000, and the glass transition temperature Tg is The softening point temperature was 56 ° C and 120 ° C. Further, as a result of measuring the molecular weight of the styrene-acrylic resin portion separated from the hybrid resin particles, the weight average molecular weight (Mw) measured by GPC was 53,000, the number average molecular weight (Mn) was 8,500, and the molecular weight. The distribution (Mw / Mn) was 6.2, the glass transition temperature Tg was 52 ° C, and the softening point temperature was 117 ° C. The size of the hybrid resin particles (3) was 210 nm in terms of number average primary particle size.

<Preparation Example 4 of Hybrid Resin Particle>
An attempt was made to prepare the hybrid resin particles in the same manner as in the hybrid resin particle preparation example 1 except that 2 g of sodium dodecylbenzene sulfonate was used instead of 2 g of dodecylbenzene sulfonate, and the polycondensation reaction proceeded. The polyester resin was not polymerized and the hybrid resin particles could not be obtained.

<Preparation Example 1 of Colorant Dispersion>
1.0 g of anionic surfactant sodium dodecylbenzenesulfonate was dissolved in 30 ml of ion-exchanged water with stirring. While stirring this solution, 7 g of carbon black “Regal 330R” (manufactured by Cabot) is gradually added as a colorant, and then a mechanical disperser “Claremix” (manufactured by M Technique Co., Ltd.) is used. A dispersion of colorant particles (hereinafter also referred to as “colorant dispersion”) (1) was prepared by dispersion treatment. When the particle diameter of the colorant particles in the obtained colorant dispersion (1) was measured using a Microtrac UPA particle size distribution analyzer “9340-UPA” (manufactured by HONEYWELL), the volume average particle diameter (weighted by volume) Average particle diameter) was 92 nm.

<Preparation Example 2 of Colorant Dispersion>
In the colorant dispersion preparation example 1, the same procedure as in the colorant dispersion preparation example 1 except that 8 g of the pigment “CI Pigment Yellow 185” was used instead of 7 g of carbon black. 2) was prepared. The particle diameter of the colorant particles in the obtained colorant dispersion (2) was measured using a Microtrac UPA particle size distribution analyzer “9340-UPA” (manufactured by HONEYWELL), and the volume average particle diameter was 87 nm. It was.

<Preparation Example 3 of Colorant Dispersion>
In Preparation Example 1 of Colorant Dispersion, Colorant was prepared in the same manner as Preparation Example 1 of Colorant Dispersion except that 8 g of quinacridone-based magenta pigment “CI Pigment Red 122” was used instead of 7 g of carbon black. Dispersion (3) was prepared. The particle diameter of the colorant particles in the obtained colorant dispersion (3) was measured using a Microtrac UPA particle size distribution analyzer “9340-UPA” (manufactured by HONEYWELL), and the volume average particle diameter was 90 nm. It was.

<Preparation Example 4 of Colorant Dispersion>
In Preparation Example 1 of Colorant Dispersion, the same procedure as in Preparation Example 1 of Colorant Dispersion was used, except that 7 g of phthalocyanine cyan pigment “CI Pigment Blue 15: 3” was used instead of 7 g of carbon black. A colorant dispersion (4) was prepared. The particle diameter of the colorant particles in the obtained colorant dispersion (4) was measured using a Microtrac UPA particle size distribution analyzer “9340-UPA” (manufactured by HONEYWELL), and the volume average particle diameter was 90 nm. It was.

<Preparation Example 1 of Wax Dispersion>
1.0 g of anionic surfactant sodium dodecylbenzenesulfonate was dissolved in 30 ml of ion-exchanged water with stirring. While heating this solution to 90 ° C. and stirring, 7 g of carnauba wax (refined carnauba wax No. 1) as a wax was dissolved by heating to 90 ° C., and then a mechanical disperser was added. Dispersion treatment was carried out at 90 ° C. for 7 hours using “CLEAMIX” (manufactured by M Technique Co., Ltd.), then cooled to 30 ° C., and a wax dispersion (hereinafter referred to as “wax dispersion”) (1) ) Was prepared. When the particle size of the wax in the obtained wax dispersion (1) was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the volume-based median diameter was 95 nm. .

<Preparation Example 2 of Wax Dispersion>
1.0 g of anionic surfactant sodium dodecylbenzenesulfonate was dissolved in 30 ml of ion-exchanged water with stirring. This solution was heated to 90 ° C., and while stirring, 7 g of pentaerythritol tetrabehenate ester dissolved as a wax was heated to 90 ° C. and dissolved, and then the mechanical disperser “CLEAMIX” ( M Technic Co., Ltd.) was used for dispersion treatment at 90 ° C. for 7 hours, and then cooled to 30 ° C. to prepare a wax dispersion (2). When the particle size of the wax in the obtained wax dispersion (2) was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the volume-based median diameter was 96 nm. .

<Preparation Example 3 of Wax Dispersion>
1.0 g of anionic surfactant sodium dodecylbenzenesulfonate was dissolved in 30 ml of ion-exchanged water with stirring. This solution is heated to 90 ° C., and while stirring, 7 g of Fischer-Tropsch wax heated to 90 ° C. and dissolved as a wax is gradually added. Then, a mechanical disperser “Clearmix” (M Technique) For 7 hours at 90 ° C. and then cooled to 30 ° C. to prepare a wax dispersion (3). When the particle size of the wax in the obtained wax dispersion (3) was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the volume-based median diameter was 91 nm. .

<Production Example K1 of Colored Particles>
In a reaction vessel (four-necked flask) equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a stirring device, mixed resin particles (1), 30 g of ion-exchanged water, a colorant dispersion (1) and a wax dispersion (1) was prepared, and the internal temperature was adjusted to 30 ° C., and then a 5N sodium hydroxide aqueous solution was added to the aggregation dispersion to adjust the pH to 10.0. Next, an aqueous solution in which 1 g of magnesium chloride hexahydrate was dissolved in 20 ml of ion-exchanged water was added at 30 ° C. over 10 minutes with stirring. After standing for 1 minute, the temperature increase was started, and the temperature of this association system was increased to 90 ° C. over 10 minutes. Stirring as shown in FIG. 1 was used for stirring.
In this state, the particle size of the aggregated particles was measured with a flow particle image analyzer “FPIA2000” (manufactured by Sysmex Corporation), and when the number average particle size reached 5.2 μm, 2 g of sodium chloride was added to 20 ml of ion-exchanged water. The dissolved aqueous solution was added to stop the particle growth, and further, the mixture was heated and stirred at 95 ° C. for 10 hours to continue fusion and shape control, and then the system was cooled to 30 ° C., Hydrochloric acid was added to adjust the pH to 2.0 and stirring was stopped.
The produced particles were filtered, washed repeatedly with ion exchange water at 45 ° C., and then dried with hot air at 40 ° C. to obtain colored particles (K1).
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of the colored particles without corners for the colored particles (K1).

<Colored Particle Production Example K2>
In Production Example K1 of the colored particles, the hybrid resin particles (2) are used instead of the hybrid resin particles (1), the wax dispersion (2) is used instead of the wax dispersion (1), and the dispersion mixture is further mixed. The colored particles (K2) were obtained in the same manner as in the colored particle production example K1, except that the pH of the liquid was adjusted to 11.0 and the particle growth was stopped when the number average particle size reached 5.5 μm. It was.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of colored particles without corners for the colored particles (K2).

<Colored Particle Production Example K3>
In the colored particle production example K1, the hybrid resin particles (3) are used instead of the hybrid resin particles (1), the wax dispersion (3) is used instead of the wax dispersion (1), and the dispersion mixture is further mixed. The colored particles (K3) were obtained in the same manner as in the colored particle production example K1 except that the pH of the liquid was adjusted to 10.5 and the particle growth was stopped when the number average particle size reached 5.5 μm. It was.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of colored particles without corners for the colored particles (K3).

<Production Example K4 of Colored Particles>
In the colored particle production example K1, colored particles (K4) were obtained in the same manner as in the colored particle production example K1 except that an ordinary vertical stirring apparatus was used as the stirring apparatus.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of the colored particles without corners for the colored particles (K4).

<Production Example Y1 of Colored Particles>
In the production example K1 of the colored particles, except that the colorant dispersion (2) is used instead of the colorant dispersion (1), and the particle growth is stopped when the number average particle diameter becomes 5.5 μm. Produced colored particles (Y1) in the same manner as in Production Example K1 of colored particles.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of colored particles without corners for the colored particles (Y1).

<Production Example Y2 of Colored Particles>
In Production Example K2 of the colored particles, the colorant dispersion (2) is used instead of the colorant dispersion (1), the pH of the dispersion liquid mixture is adjusted to 9.0, and the number average particle diameter is 5. Colored particles (Y2) were obtained in the same manner as in Colored Particle Production Example K2 except that the particle growth was stopped when the particle size reached 4 μm.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of colored particles without corners for the colored particles (Y2).

<Production Example Y3 of Colored Particles>
In Colored Particle Production Example K3, except that the colorant dispersion (2) was used instead of the colorant dispersion (1), and the particle growth was stopped when the number average particle size reached 5.3 μm. Produced colored particles (Y3) in the same manner as in Colored Particle Production Example K3.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of the colored particles without corners for the colored particles (Y3).

<Production Example Y4 of Colored Particles>
In colored particle production example Y1, colored particles (Y4) were obtained in the same manner as in colored particle production example Y1, except that a normal vertical stirring apparatus was used as the stirring apparatus.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of colored particles without corners for the colored particles (Y4).

<Production Example M1 of Colored Particles>
In Colored Particle Production Example K1, except that the colorant dispersion (3) was used instead of the colorant dispersion (1), and the particle growth was stopped when the number average particle diameter reached 5.5 μm. Produced colored particles (M1) in the same manner as in Colored Particle Production Example K1.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of the colored particles without corners for the colored particles (M1).

<Example M2 of colored particles>
In Production Example K2 of the colored particles, the colorant dispersion (3) is used instead of the colorant dispersion (1), the pH of the dispersion liquid mixture is adjusted to 9.0, and the number average particle diameter is 5. Colored particles (M2) were obtained in the same manner as in Colored Particle Production Example K2, except that the particle growth was stopped when the particle size reached 4 μm.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of the colored particles without corners for the colored particles (M2).

<Production Example M3 of Colored Particles>
In Colored Particle Production Example K3, except that the colorant dispersion (3) was used instead of the colorant dispersion (1), and the particle growth was stopped when the number average particle diameter reached 5.3 μm. Gave colored particles (M3) in the same manner as in Production Example K3 of colored particles.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of the colored particles without corners for the colored particles (M3).

<Example M4 of colored particles>
In the colored particle production example M1, colored particles (M4) were obtained in the same manner as in the colored particle production example M1, except that an ordinary vertical stirring apparatus was used as the stirring apparatus.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of colored particles without corners for the colored particles (M4).

<Colored Particle Production Example C1>
In the production example K1 of the colored particles, the colorant dispersion (4) was used instead of the colorant dispersion (1), and the particle growth was stopped when the number average particle diameter reached 5.5 μm. Gave colored particles (C1) in the same manner as in Colored Particle Production Example K1.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of the colored particles without corners for the colored particles (C1).

<Colored Particle Production Example C2>
In Production Example K2 of the colored particles, the colorant dispersion (4) is used instead of the colorant dispersion (1), the pH of the dispersion liquid mixture is adjusted to 9.0, and the number average particle diameter is 5. Colored particles (C2) were obtained in the same manner as in Colored Particle Production Example K2 except that the particle growth was stopped when the particle size reached 4 μm.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of the colored particles without corners for the colored particles (C2).

<Production Example C3 of Colored Particles>
In Colored Particle Production Example K3, except that the colorant dispersion (4) was used instead of the colorant dispersion (1), and the particle growth was stopped when the number average particle size reached 5.3 μm. Gave colored particles (C3) in the same manner as in Colored Particle Production Example K3.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of colored particles without corners for the colored particles (C3).

<Colored Particle Production Example C4>
In the colored particle production example C1, colored particles (C4) were obtained in the same manner as in the colored particle production example C1 except that an ordinary vertical stirring apparatus was used as the stirring apparatus.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of the colored particles without corners for the colored particles (C4).

<Example of toner production>
In each of 100 parts by mass of the above 16 kinds of colored particles (K1) to colored particles (C4), 1.0 part by mass of silica having a number average primary particle diameter of 12 nm and a hydrophobicity of 80, and a number average primary Toner (K1) to toner (C4) were obtained by adding 1.0 part by mass of titania having a particle size of 25 nm and a hydrophobization degree of 80 and mixing using a Henschel mixer.
The shape and particle size of the toner particles constituting these toners did not change depending on the addition of an external additive.

<Comparative Toner Production Example 1>
299 g of terephthalic acid, 211 g of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, and 82 g of pentaerythritol, thermometer, stainless steel stirrer, glass nitrogen gas inlet tube The flask was placed in a round bottom flask equipped with a downflow condenser, this flask was set in a mantle heater, and nitrogen gas was introduced from a nitrogen gas introduction tube to raise the temperature while maintaining the inside of the flask in an inert atmosphere. Then, 0.05 g of dibutyltin oxide was added, and the reaction was conducted at a temperature of 200 ° C. while monitoring the reaction at the softening point temperature, thereby producing a polyester resin A having a chloroform insoluble content of 17% by mass. This polyester resin A had a glass transition temperature of 59 ° C. and a softening temperature of 131 ° C.
Styrene-acrylic resin (styrene-derived component and butyl acrylate-derived component in a weight ratio of 72:28, glass transition temperature: 53 ° C., softening point temperature: 121 ° C.) 90 to 100 parts by mass of polyester resin A 90 Mass parts, 6 parts by mass of carbon black and 6 parts by mass of pentaerythritol tetrabehenate are mixed, melted, kneaded, cooled, pulverized and classified, and a colored particle for comparison having a volume-based median diameter of 6.8 μm (K5) Then, 1.0 part by mass of silica having a number average primary particle diameter of 12 nm and a hydrophobization degree of 80, and 1.0 part by mass of titania having a number average primary particle diameter of 25 nm and a hydrophobization degree of 80 are obtained. Was added and mixed using a Henschel mixer to obtain a comparative toner (K5).
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of colored particles without corners for the comparative colored particles (K5).

<Production Example 2 for Comparative Toner>
In Comparative Toner Production Example 1, the volume-based median diameter was the same as that of the comparative colored particles (K5) except that 8 parts by mass of the pigment “CI Pigment Yellow 185” was used instead of carbon black. A comparative colored particle (Y5) of 6.4 μm was obtained, and a comparative toner (Y5) was obtained in the same manner as in Production Example 1 for the comparative toner.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of colored particles without corners for the comparative colored particles (Y5).

<Production Example 3 for Comparative Toner>
In Comparative Toner Production Example 1, a volume-based measurement was performed in the same manner as Comparative Colored Particles (K5), except that 9 parts by mass of quinacridone-based magenta pigment “CI Pigment Red 122” was used instead of carbon black. Comparative colored particles (M5) having a median diameter of 6.4 μm were obtained, and a comparative toner (M5) was obtained in the same manner as in Comparative toner production example 1.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of colored particles without corners for the comparative colored particles (M5).

<Production Example 4 for Comparative Toner>
In Comparative Toner Production Example 1, the volume was the same as Comparative Colored Particles (K5) except that 9 parts by weight of talocyanine cyan pigment “CI Pigment Blue 15: 3” was used instead of carbon black. A comparative colored particle (C5) having a standard median diameter of 6.4 μm was obtained, and a comparative toner (C5) was obtained in the same manner as in Comparative toner production example 1.
Table 1 shows the shape factor, the variation coefficient of the shape factor, the number variation coefficient in the number particle size distribution, and the ratio of colored particles without corners for the comparative colored particles (C5).

<Examples of developer production>
20 g of each of the 16 types of toners (K1) to (C4) and 4 types of comparative toners (K5) to (C5) manufactured as described above and 400 g of a 45 μm ferrite carrier coated with an acrylic resin are mixed. Thus, developers (K1) to (C4) and comparative developers (K5) to (C5) were produced.

<Examples 1-4, Comparative Example 1>
Using a copier “bizhub C500” (manufactured by Konica Minolta), 16 types of developers (K1) to (C4) and 4 types of comparative developers (K5) to (C5) are converted into a developer (K1). , Developer (Y1), Developer (C1) and Developer (M1) in combination (Example 1), Developer (K2), Developer (Y2), Developer (C2) and Developer (M2) Combination (Example 2), Developer (K3), Developer (Y3), Developer (C3) and Developer (M3) (Example 3), Developer (K4), Developer (Y4), Used in combination of developer (C4) and developer (M4) (Example 4), full-color image formation was performed under the following conditions, fog density, in-machine contamination, fine line reproducibility, and fixing by the following methods The presence or absence of offset generation was evaluated. The results are shown in Table 2.

[Latent image carrier]: A laminated organic photoconductor was used as the latent image carrier, and the surface potential of the photoconductor was set to -750V.
[Developer]: A developer of the contact development type was used as the developer, and an alternating voltage with an alternating current frequency of 2000 Hz and a peak-to-peak voltage (V _pp ) of 2700 V was applied to be applied to a DC voltage of −610 V.

[Fixing device]: A fixing device of a pressure heating fixing type was used as the fixing device. The configuration is as follows.
It has an upper roller made of columnar iron with a 30 mm diameter heater coated at the center and coated with a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and the surface is similarly tetrafluoroethylene-perfluoroalkyl ether It has a lower roller 30 mm in diameter composed of silicone rubber coated with a copolymer. The linear pressure was set to 0.8 kg / cm, and the nip width was 4.3 mm.
Using this fixing device, the linear speed of printing was set to 250 mm / sec. The fixing temperature was controlled by the surface temperature of the upper roller, and was set to a set temperature of 185 ° C. In addition, as a cleaning mechanism for the fixing device, a system in which a pad impregnated with polydiphenyl silicone (having a viscosity of 10,000 cp at 20 ° C.) is pressed is used.

[Evaluation of fog density and in-flight contamination]
About the blank paper which is not printed, the absolute image density of 20 places is measured using the Macbeth reflection densitometer “RD-918”, and averaged to obtain the blank paper density. Then, in full color, an image is formed over 200000 sheets in a high-temperature and high-humidity environment (temperature 35 ° C., humidity 85% RH) in a single-sheet intermittent mode with a pixel rate of 15% for each color. Similarly, for the white background portion of the image, the absolute image density at 20 locations was measured and averaged, and the value obtained by subtracting the white paper density from this average density was evaluated as the fog density. If the fog density is 0.005 or less, it can be said that the fog is not a practical problem.
Further, after forming 200,000 sheets of images, the lower part of the developing unit in the apparatus was visually observed to evaluate contamination in the apparatus due to toner scattering.

[Evaluation of fine line reproducibility]
In the image formation of 200,000 sheets performed by the above fog density evaluation, the resolution (thin line reproducibility) of a line drawing in which toner of four colors was composed of each dot was evaluated at the initial stage of image formation and after the formation of 200,000 sheets. The line drawing was formed in a direction transverse to the developing direction of the image forming apparatus, and the resolution was evaluated by measuring the number of identifiable fine lines per 1 mm. Here, the “identifiable thin line” means a line that can be continuously distinguished without being divided when observed with a magnifying glass having a magnification of 10 times.

[Evaluation of occurrence of fixing offset and pad dirt]
Using a full-color halftone image formed at a pixel rate of 5% for each color, 10,000 sheets are printed continuously at low temperature and low humidity (temperature 10 ° C., humidity 10% RH). Next, after the machine was stopped overnight, the machine was started up again, and the presence / absence of image contamination due to the fixing offset phenomenon occurring on the first sheet and the state of the pad contamination were visually evaluated.
When the evaluation is performed in a low temperature environment, the toner is difficult to be fixed to the transfer material because the temperature of the transfer material used is low. In particular, when printing is performed continuously, the surface temperature of the upper roller gradually decreases, so that fixing becomes difficult. If the toner has low fixability on the transfer material, a part of the toner moves to the upper roller of the fixing device to cause a fixing offset phenomenon, and the pad is pressed against the upper roller as a cleaning mechanism of the fixing device. If a toner is used, the toner that has not been fixed and has moved to the upper roller is accumulated in the pad. In the first printing after the machine is sufficiently stopped, the surface temperature of the upper roller is sufficiently high, so that the toner accumulated in the pad is discharged and a fixing offset phenomenon occurs. .

  As is apparent from Table 2, in the image formation performed using the toners according to Examples 1 to 4, the fog density in the formed image is 0.005 or less, and the fog is not substantially generated. confirmed. Further, it was confirmed that the fixing offset and the pad contamination were generated only to the extent that there was no practical problem. On the other hand, in the image formation performed using the toner according to Comparative Example 1, fogging was generated, fixing offset and pad smear were observed.

It is a perspective view which shows an example of a reaction apparatus. (A) is explanatory drawing which shows the projection image of the colored particle without an angle | corner, (b) and (c) are explanatory drawings which show the projection image of the colored particle with an angle | corner, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat exchange jacket 2 Stirrer tank 3 Rotating shaft 4a, 4b Stirring blade 7 Upper material inlet 8 Lower material inlet α Crossing angle

Claims (12)

In an aqueous medium containing a surfactant composed of a compound having a long-chain hydrocarbon group and an acidic group, a heavy polymer comprising at least one divalent or higher carboxylic acid and at least one divalent or higher alcohol. Forming oil droplets of a composition for forming a hybrid resin particle containing a condensable monomer and a radical polymerizable monomer comprising at least one styrene compound and at least one (meth) acrylate compound;
In the oil droplet, a polycondensation step of synthesizing a polyester resin by subjecting the carboxylic acid and the alcohol to a polycondensation reaction and a radical copolymerization reaction of the styrene compound and the (meth) acrylic ester compound to produce a styrene-acrylic A polymerization step of obtaining a hybrid resin particle containing a polyester resin and a styrene-acrylic resin by performing a radical copolymerization step of synthesizing a resin.
A method for producing a toner, comprising: an aggregating step of aggregating at least the hybrid resin particles in an aqueous medium.   The toner production method according to claim 1, wherein the acidic group of the surfactant is any one of a sulfonic acid group, a phosphoric acid group, and a carboxylic acid group.   The method for producing a toner according to claim 1, wherein the surfactant contained in the aqueous medium has a critical micelle concentration or less.   The method for producing a toner according to any one of claims 1 to 3, wherein the compound relating to the surfactant has a hydrocarbon group of 8 to 40 carbon atoms.   The method for producing a toner according to claim 1, wherein the aggregation step is performed in the aqueous medium in which the polymerization step has been performed.   6. The polycondensable monomer contains at least one trivalent or higher carboxylic acid and / or at least one trivalent or higher alcohol. A method for producing the toner according to claim 1.   A toner obtained by the method for producing a toner according to claim 1.   The toner according to claim 7, wherein a ratio of toner particles having a shape factor in the range of 1.0 to 1.6 is 65% by number or more with respect to the toner particles formed of the colored particles.   9. The toner according to claim 7, wherein the toner particles formed of the colored particles are toner particles having a variation coefficient of a shape factor of 16% or less.   The toner according to any one of claims 7 to 9, wherein the toner particles formed of the colored particles are toner particles having a number variation coefficient of 27% or less in the number particle size distribution.   11. The toner according to claim 7, wherein a ratio of colored particles having no corners is 50% by number or more.   In an image forming method including a step of developing a latent image formed on a latent image carrier with a developer containing toner and visualizing the latent image, the toner is transferred to a transfer material. An image forming method using the toner according to any one of the above.