JP2012128025A - Production method of magenta toner for electrophotography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magenta toner for electrophotography excellent in fixability and image density, and to provide a method for producing the same.SOLUTION: There are provided a production method of a magenta toner for electrophotography includes the following steps (1) to (3), and the magenta toner for the electrophotography obtained by the method. The method comprises: (1) melting and mixing a polyester resin (a) and a pigment expressed by the formula to obtain a colored resin (in the formula, M represents barium, calcium, strontium or manganese); (2) melting and mixing the colored resin with a polyester resin (b) in the presence of an aqueous liquid having a pH of 7 to 11, followed by emulsifying the resultant mixture to obtain colored resin particles (A); and (3) aggregating and fusing the colored resin particles (A).

Description

  The present invention relates to a method for producing an electrophotographic magenta toner, and an electrophotographic magenta toner obtained thereby.

In the field of electrophotographic toner, with the development of an electrophotographic system, development of a toner corresponding to high image quality and high speed is required.
In order to meet the demands for higher image quality and higher speed, toners are also required to have various performances. As a method for adjusting the particle size and surface property by using a single particle, a toner production method by an aggregation coalescence method (aggregation fusion method) has been proposed.

For example, Patent Document 1 discloses that a resin having an acid group is neutralized in a basic aqueous medium in order to obtain a toner having a high image density and chargeability by preventing the colorant from being modified. A step of obtaining a dispersion, at a temperature not lower than [softening temperature of acid group-containing resin by flow tester method (Ts) −20 ° C.] and not higher than [softening point of acid group-containing resin by flow tester method (Tm)], Color Index Pigment Red 48: 1, Color Index Pigment Red 48: 2, Color Index Pigment Red 48: 3, and Color Index Pigment Red 48: 4 A method for producing a colorant-containing resin particle dispersion comprising: a step of obtaining a mixed dispersion, and a step of adding an aqueous liquid to the obtained colorant and resin mixed dispersion to obtain a colorant-containing resin particle dispersion. It is disclosed.
In Patent Document 2, for the purpose of economically producing a toner having excellent dispersibility of a colorant, a binder resin and a masterbatch of a colorant in which the colorant is dispersed in the resin are mixed and non-ionic An electrophotographic toner manufacturing method comprising a step of producing primary particles in an aqueous medium in the presence of a surfactant and a step of aggregating and coalescing the primary particles is disclosed.

JP 2010-65199 A JP 2006-171691 A

The toner is manufactured by kneading at a high temperature or processing in an aqueous medium by an agglomeration and fusion method. Therefore, magenta toner pigments in color toners generally include quinacridone having excellent heat resistance and water resistance. Condensed polycyclic pigments are used. On the other hand, lake pigments exhibit high color developability, but are difficult to use in toners while taking advantage of color developability because they are denatured and faded during kneading at high temperatures or in production in an aqueous medium.
Further, the toner is required to have a performance capable of being fixed on a recording medium in a very wide temperature range. Although the fixing temperature range of the toner can be improved by using the cohesive fusion method described in the above-mentioned patent document, the fixing temperature range cannot be sufficiently improved when the lake pigment is used.
An object of the present invention is to provide an electrophotographic magenta toner excellent in fixing property and image density and a method for producing the same.

  The inventors of the present invention have considered that the factors affecting the fixing property and the image density are the stability of the pigment and the state and position of the resin constituting the toner in the toner. As a result, after the polyester resin and a specific pigment are melt-mixed, the polyester resin and a specific pH aqueous solution are melt-mixed and then emulsified, aggregated, and fused, thereby fixing and fixing the image. It has been found that a magenta toner for electrophotography having an excellent density can be obtained.

That is, the present invention provides the following [1] and [2].
[1] A method for producing an electrophotographic magenta toner comprising the following steps (1) to (3):
Step (1): Step of obtaining a colored resin by melt-mixing the polyester resin (a) and a pigment represented by the following formula

(In the formula, M represents barium, calcium, strontium or manganese.)
Step (2): Step of obtaining colored resin particles (A) by melting and mixing the colored resin and the polyester resin (b) in the presence of an aqueous liquid having a pH of 7 to 11 to obtain colored resin particles (A) Step (3): Colored resin Step of aggregating and fusing particles (A) [2] A magenta toner for electrophotography obtained by the production method described in [1] above.

  According to the method of the present invention, an electrophotographic magenta toner having excellent fixability and image density can be produced efficiently and at low cost.

The method for producing an electrophotographic magenta toner of the present invention includes the following steps (1) to (3).
Step (1): Step of obtaining a colored resin by melt-mixing the polyester resin (a) and a pigment represented by the following formula

(In the formula, M represents barium, calcium, strontium or manganese.)
Step (2): Step of obtaining colored resin particles (A) by melting and mixing the colored resin and the polyester resin (b) in the presence of an aqueous liquid having a pH of 7 to 11 to obtain colored resin particles (A) Step (3): Colored resin Aggregating and fusing particles (A)

The reason why the electrophotographic magenta toner obtained by the production method of the present invention is excellent in fixability and image density is not clear, but is considered as follows.
First, in step (1), the polyester resin (a) and the pigment represented by the above formula are melt-mixed to obtain a colored resin in which the pigment is uniformly dispersed inside the polyester resin (a). . Thus, it is considered that the color developability of the pigment can be maintained in the treatment in the aqueous medium in the subsequent step or the treatment at a high temperature.
Next, in the step (2), the colored resin and the polyester resin (b) are melt-mixed in the presence of an aqueous liquid having a pH of 7 to 11. As the polyester resin (b) used in this step, a resin suitable for the dispersibility in an aqueous medium in the subsequent step and the fixing property which is the property of the obtained toner can be selected. Thus, it is considered that the color development and fixing properties of the toner can both be achieved by melting and mixing the polyester resin and the pigment in two stages.
Moreover, in this process (2), after melt-mixing in presence of the aqueous liquid of pH 7-11, it emulsifies and obtains a colored resin particle (A). Here, it is considered that the dispersion stability of the resin particles and the stability of the pigment can be maintained by melt-mixing the pH in a neutral to weakly alkaline region.
In the step (3), the colored resin particles (A) thus obtained are agglomerated and fused, so that it is considered that an electrophotographic magenta toner having excellent fixability and image density can be obtained.

First, each component used in the present invention will be described.
[Polyester resin (a)]
Hereinafter, the polyester resin (a) will be described.
In the present invention, the polyester resin (a) is preferably a linear polyester resin from the viewpoint of improving toner fixability.
The polyester resin (a) is preferably an amorphous polyester from the viewpoint of improving the chargeability of the toner. Amorphous polyester is a crystal defined by the ratio between the softening point and the maximum endothermic peak temperature measured by a differential scanning calorimeter (DSC), (softening point (° C)) / (maximum endothermic peak temperature (° C)). A polyester having a sex index greater than 1.4 or less than 0.6.
The crystallinity index of the polyester resin (a) is preferably less than 0.6 or more than 1.4 and 4 or less, more preferably less than 0.6 or 1.5 or more and 4 or less, from the viewpoint of low-temperature fixability of the toner. More preferably, it is less than 0.6 or 1.5 or more and 3 or less, More preferably, it is less than 0.6 or 1.5 or more and 2 or less. The crystallinity index can be appropriately determined depending on the type and ratio of raw material monomers, production conditions (for example, reaction temperature, reaction time, cooling rate), and the like.

The polyester resin (a) preferably has an acid group at the molecular end from the viewpoint of emulsifiability. Examples of the acid group include a carboxyl group, a sulfonic acid group, a phosphonic acid group, and a sulfinic acid. Among these, a carboxyl group is preferable from the viewpoint of achieving both the dispersibility of the resin and the storage stability of the toner.
The acid value of the polyester resin (a) is preferably 6 to 35 mgKOH / g, more preferably 10 to 35 mgKOH / g, and still more preferably 15 to 35 mgKOH / g, from the viewpoint of emulsification in the aqueous medium of the resin.
The number average molecular weight of the polyester resin (a) is preferably 1,000 to 50,000, more preferably 1,000 to 10,000, and still more preferably, from the viewpoints of toner durability, low-temperature fixability and storage stability. Is 2,000 to 8,000.

The glass transition point of the polyester resin (a) is preferably 50 to 75 ° C., more preferably 52 to 70 ° C., and still more preferably 55 to 68 ° C. from the viewpoints of toner durability, low-temperature fixability and storage stability. is there.
The softening point of the polyester resin (a) is preferably 70 to 165 ° C, more preferably 70 to 140 ° C, still more preferably 80 to 130 ° C, from the viewpoint of toner durability, low-temperature fixability and storage stability. Preferably it is 90-120 degreeC.
In addition, when using 2 or more types of polyester resin (a) in mixture, the glass transition point and softening point are obtained by the method of an Example as a mixture of 2 or more types of polyester resins (a), respectively. The glass transition point and softening point.

The polyester resin (a) is obtained by polycondensation reaction between an acid component and an alcohol component. The polycondensation reaction is preferably performed at 180 to 250 ° C. in the presence of a catalyst.
Examples of the acid component include a dicarboxylic acid, a succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, and a polyvalent carboxylic acid having 3 or more valences. Anhydrides and alkyl (C1-C3) esters are also included. Among these, dicarboxylic acid is preferable from the viewpoint of storage stability and chargeability of the toner.
Dicarboxylic acids include dicarboxylic acids containing aromatic rings such as phthalic acid, isophthalic acid, and terephthalic acid, and aliphatic dicarboxylic acids such as sebacic acid, fumaric acid, maleic acid, adipic acid, azelaic acid, succinic acid, and cyclohexanedicarboxylic acid. Examples thereof include fumaric acid.
Examples of the succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid.
Examples of the trivalent or higher polyvalent carboxylic acid include trimellitic acid, 2,5,7-naphthalene tricarboxylic acid, and pyromellitic acid.
These acid components can be used alone or in combination of two or more.
The polyester resin (a) contains an acid component containing a trivalent or higher polyvalent carboxylic acid and its acid anhydride or its alkyl ester, preferably trimellitic acid or its anhydride, from the viewpoint of high temperature offset resistance of the toner. It is preferable to use at least one polyester resin (a) obtained by using the polyester resin.

Examples of the alcohol component include aliphatic diols having 2 to 12 carbon atoms in the main chain, aromatic diols, hydrogenated products of bisphenol A, and trihydric or higher polyhydric alcohols. Among these, amorphous polyesters are used. From the viewpoint of obtaining aromatic diols, aromatic diols are preferred, and alkylenes of bisphenol A such as polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene-2,2-bis (4-hydroxyphenyl) propane ( C2-C3) oxide adduct (average addition mole number 1-16) is more preferable.
Examples of the aliphatic diol having 2 to 12 carbon atoms include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexane. Diol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, neopentyl glycol, 1,4-butenediol, etc. It is done.
Examples of the trihydric or higher polyhydric alcohol include glycerin and pentaerythritol.
These alcohol components can be used alone or in combination of two or more.

As a catalyst, a tin compound, a titanium compound, etc. are preferable from a viewpoint of the efficiency of a condensation polymerization reaction, and a tin compound is more preferable. Examples of the tin compound include tin dioctylate and dibutyltin oxide. Examples of the titanium compound include titanium diisopropylate bistriethanolamate.
Although there is no restriction | limiting in the usage-amount of a catalyst, Preferably it is 0.01-1 weight part with respect to 100 weight part of total amounts of an acid component and an alcohol component, More preferably, it is 0.1-0.6 weight part.

  The polycondensation reaction is preferably carried out by adding an acid component and an alcohol component to a reaction vessel and maintaining at 180 to 250 ° C. for 5 to 15 hours, and then adding a catalyst and maintaining at 180 to 250 ° C. for 1 to 5 hours. More preferably, the reaction is allowed to proceed, and the pressure is reduced to 5.0 to 20 kPa and maintained for 1 to 10 hours.

（式中、Ｍはバリウム、カルシウム、ストロンチウム又はマンガンを表す。） [Pigment]
The pigment used in the present invention is a pigment represented by the following formula.

(In the formula, M represents barium, calcium, strontium or manganese.)

The pigment is 4-[(5-chloro-4-methyl-2-sulfonatophenyl) azo] -3-hydroxy-2-naphthoate, pigment red 48: 1 (M = barium), pigment red 48 : 2 (M = calcium), Pigment Red 48: 3 (M = Strontium), and Pigment Red 48: 4 (M = Manganese). Among these, Pigment Red 48: 3, in which M is strontium, is preferable from the viewpoint of improving the image density and exhibiting a preferable color tone as a magenta toner.
A pigment can be used individually or in combination of 2 or more types.

The pigment used in the present invention may be in any form such as a dry powder or a paste moistened in water, but is preferably a paste moistened in water from the viewpoint of dispersibility in the resin.
The solid content concentration of the paste wetted with water is preferably 10 to 50% by weight, more preferably 15 to 40% by weight from the viewpoints of pigment dispersibility and wettability, and toner image density, particle size distribution and productivity. 20 to 35% by weight is preferable.

  In the present invention, a pigment other than the pigment represented by the above formula can be used as long as the effects of the present invention are not impaired. Examples of pigments other than the pigment represented by the above formula include Pigment Red 122 and Pigment Red 269.

[Polyester resin (b)]
As the polyester resin (b), a resin having the same composition as the polyester resin (c) described later may be used, or a resin having a different composition may be used. It is preferable to use a resin. In addition, the suitable range is the same also about the polyester resin (c) mentioned later.

In the present invention, the polyester resin (b) is preferably a cross-linked polyester resin from the viewpoint of improving the fixability of the toner.
The polyester resin (b) is preferably an amorphous polyester from the viewpoint of improving the chargeability of the toner.
The crystallinity index of the polyester resin (b) is preferably less than 0.6 or more than 1.4 and 4 or less, more preferably less than 0.6 or 1.5 or more and 4 or less, from the viewpoint of low-temperature fixability of the toner. More preferably, it is less than 0.6 or 1.5 or more and 3 or less, More preferably, it is less than 0.6 or 1.5 or more and 2 or less. The crystallinity index can be appropriately determined depending on the type and ratio of raw material monomers, production conditions (for example, reaction temperature, reaction time, cooling rate), and the like.

The polyester resin (b) preferably has an acid group at the molecular end from the viewpoint of emulsification. Examples of the acid group include a carboxyl group, a sulfonic acid group, a phosphonic acid group, and a sulfinic acid. Among these, a carboxyl group is preferable from the viewpoint of achieving both the dispersibility of the resin and the storage stability of the toner.
The acid value of the polyester resin (b) is preferably 6 to 35 mgKOH / g, more preferably 10 to 35 mgKOH / g, and still more preferably 15 to 35 mgKOH / g, from the viewpoint of emulsification in the aqueous medium of the resin.
The number average molecular weight of the polyester resin (b) is preferably 1,000 to 50,000, more preferably 1,000 to 10,000, and still more preferably, from the viewpoints of toner durability, low-temperature fixability and storage stability. Is 2,000 to 8,000.

The glass transition point of the polyester resin (b) is preferably 55 to 75 ° C., more preferably 55 to 70 ° C., and still more preferably 58 to 68 ° C. from the viewpoint of toner durability, low-temperature fixability and storage stability. is there.
The softening point of the polyester resin (b) is preferably 70 to 165 ° C, more preferably 70 to 140 ° C, still more preferably 90 to 140 ° C, from the viewpoint of toner durability, low-temperature fixability and storage stability. Preferably it is 100-130 degreeC.
In addition, when using 2 or more types of polyester resin (b) mixed, the glass transition point and softening point are obtained by the method of an Example as a mixture of 2 or more types of polyester resins (b), respectively. The glass transition point and softening point.
The glass transition point, softening point, number average molecular weight and acid value of the polyester resin (b) are preferably the same as the preferred range of the polyester resin (c).

The polyester resin (b) can be produced by a polycondensation reaction between an acid component and an alcohol component in the same manner as the polyester resin (a). The acid component and the alcohol component are preferably the same components as the polyester resin (c).
Examples of the acid component include a dicarboxylic acid, a succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, and a polyvalent carboxylic acid having 3 or more valences. Anhydrides and alkyl (C1-C3) esters are also included. Among these, dicarboxylic acid is preferable from the viewpoint of storage stability and chargeability of the toner.
Dicarboxylic acids include dicarboxylic acids containing aromatic rings such as phthalic acid, isophthalic acid, and terephthalic acid, and aliphatic dicarboxylic acids such as sebacic acid, fumaric acid, maleic acid, adipic acid, azelaic acid, succinic acid, and cyclohexanedicarboxylic acid. Examples include acids, and among these, terephthalic acid is preferable.
Examples of the succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid.
Examples of the trivalent or higher polyvalent carboxylic acid include trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid and the like. Among these, trimellitic acid is preferable from the viewpoint of offset resistance.
These acid components can be used alone or in combination of two or more.
From the viewpoint of high temperature offset resistance of the toner, the polyester resin (b) contains an acid component containing a trivalent or higher polyvalent carboxylic acid and its acid anhydride or its alkyl ester, preferably trimellitic acid or its anhydride. It is preferable to use at least one polyester resin (b) obtained by using the polyester resin.

Examples of the alcohol component include aliphatic diols having 2 to 12 carbon atoms in the main chain, aromatic diols, hydrogenated products of bisphenol A, and trihydric or higher polyhydric alcohols. Among these, amorphous polyesters are used. From the viewpoint of obtaining aromatic diols, aromatic diols are preferred, and alkylenes of bisphenol A such as polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene-2,2-bis (4-hydroxyphenyl) propane ( C2-C3) oxide adduct (average addition mole number 1-16) is more preferable.
Examples of the aliphatic diol having 2 to 12 carbon atoms include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexane. Diol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, neopentyl glycol, 1,4-butenediol, etc. It is done.
Examples of the trihydric or higher polyhydric alcohol include glycerin and pentaerythritol.
These alcohol components can be used alone or in combination of two or more.

  The polyester resin (b) may be used alone or in combination of two or more, and contains two types of polyesters having different softening points from the viewpoint of low-temperature fixability, offset resistance and durability of the toner. Is preferred. When two types of polyesters having different softening points are polyesters (b-1) and (b-2), respectively, the softening point of one polyester (b-1) is preferably 70 ° C. or higher and lower than 115 ° C., and the other polyester The softening point of (b-2) is preferably 115 ° C. or higher and 165 ° C. or lower. The weight ratio of polyester (b-1) to polyester (b-2) ((b-1) / (b-2)) is preferably 10/90 to 90/10, more preferably 50/50 to 90. / 10.

[Polyacid salt]
The polybasic acid salt used in the present invention controls the pH to a specific range during the melt mixing in the step (2), and improves the dispersibility of the colored resin particles while suppressing the modification of the pigment, The image density and fixability of the toner obtained can be improved.
The salt of a polybasic acid is preferably a salt obtained from a polybasic acid and a strong base from the viewpoint of developing a buffer action for maintaining pH.

The pKa at 25 ° C. of the polybasic acid in water is preferably 2 to 10 and more preferably 4 to 9 at 25 ° C. in water at least in any dissociation stage. More preferably, it is 8.
Examples of polybasic acids include inorganic acids and organic acids, with inorganic acids being preferred.
Examples of the inorganic acid include an inorganic acid containing a phosphorus atom, carbonic acid and the like, and an inorganic acid containing a phosphorus atom is preferable. Examples of the inorganic acid containing a phosphorus atom include phosphoric acid and condensed phosphoric acid, and phosphoric acid is preferred. Examples of the condensed phosphoric acid include pyrophosphoric acid, polyphosphoric acid, and metaphosphoric acid, and pyrophosphoric acid is preferable.
Examples of the organic acid include citric acid and fumaric acid.

As a strong base, it is preferable that pKb in 25 degreeC in water is 10-14, It is more preferable that it is 12-14, It is still more preferable that it is 13-14.
Examples of strong bases include alkali metal hydroxides, tetraalkylammonium hydroxides, alkaline earth metal hydroxides, and alkali metal hydroxides are preferred. Of the alkali metal hydroxides, potassium hydroxide is preferred.

The salt of the polybasic acid exists as a mixture of salts at each dissociation stage depending on the pH. In the present invention, they are collectively referred to as “polybasic acid salts”. Examples of the salt of each dissociation stage include a salt obtained from phosphoric acid and potassium hydroxide as an example, a salt composed of phosphate ion and potassium ion (tripotassium phosphate), hydrogen phosphate ion and potassium ion, Salt (dipotassium hydrogen phosphate) consisting of dihydrogen phosphate ion and potassium ion (potassium dihydrogen phosphate). In the present invention, these are collectively referred to as “potassium phosphate phosphate”. "
Examples of polybasic acid salts include potassium phosphate, potassium citrate, potassium carbonate, sodium phosphate, sodium citrate, sodium carbonate, etc. The potassium salt is preferred.

In the step (2), the polybasic acid salt is preferably used as an aqueous solution.
The concentration of the polybasic acid salt in the aqueous solution is preferably 2 to 20% by weight, more preferably 5 to 15% by weight, and still more preferably 7 to 13% by weight in terms of the corresponding strong base.
The pH of the aqueous solution at 25 ° C. is preferably 5 to 12, more preferably 6 to 11, and still more preferably 7 to 9.
The aqueous solution is preferably obtained by mixing the weak acid and the strong base with water.
As a specific method for obtaining the aqueous solution, a method of first preparing a strong base aqueous solution, gradually adding a polybasic acid and water thereto, and adjusting to a target pH and concentration is preferable.

[Releasing agent particles]
The release agent particles are preferably obtained by dispersing the release agent in an aqueous medium.
The release agent particles preferably contain a surfactant from the viewpoint of aggregation. The content of the surfactant is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the release agent, from the viewpoints of aggregability and chargeability of the obtained toner. Parts by weight.
The volume median particle size of the release agent particles is preferably 0.1 to 1 μm, more preferably 0.1 to 0.7 μm, and still more preferably 0.1 to 0.1 μm, from the viewpoint of preventing toner chargeability and hot offset. 0.5 μm. Here, the volume-median particle size is a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% calculated from the smaller particle size.
The CV value of the release agent particles is preferably 15 to 50%, more preferably 15 to 40%, and further preferably 15 to 35%, from the viewpoint of the chargeability of the toner. The CV value is a value represented by the following formula, and is specifically obtained by the method described in the examples.
CV value (%) = [standard deviation of particle size distribution (μm) / volume average particle size (μm)] × 100

(Release agent)
As release agents, low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point upon heating; fatty acid amides such as oleic acid amide and stearic acid amide; carnauba wax, rice wax and candelilla wax Plant waxes such as beeswax; animal waxes such as beeswax; mineral / petroleum waxes such as montan wax, paraffin wax, and Fischer-Tropsch wax. These release agents can be used alone or in combination of two or more. Among these, carnauba wax is preferable from the viewpoint of improving the durability and storage stability of the toner. Carnauba wax has a moderate affinity with resin particles, and thus is unlikely to come out on the toner surface even during fusing, and is considered to improve the durability and storage stability of the toner.
The melting point of the release agent is preferably from 65 to 100 ° C., more preferably from 75 to 95 ° C., further preferably from 75 to 90 ° C., more preferably from the viewpoint of low-temperature fixability, storage stability and durability of the toner. 80-90 ° C.
In the present invention, the melting point of the release agent is determined by the method described in the examples. When two or more release agents are used in combination, the melting point of the release agent having the largest weight ratio among the release agents contained in the obtained toner is the melting point of the release agent in the present invention, and all have the same ratio. In this case, the lowest melting point is the melting point of the release agent.
The amount of the release agent used is preferably 1 to 20 parts by weight, more preferably 2 to 15 parts by weight, based on 100 parts by weight of the resin in the toner, from the viewpoint of toner releasability and chargeability.

(Manufacture of release agent particles)
The release agent particles are preferably obtained as a dispersion of release agent particles by dispersing the release agent in an aqueous medium. Furthermore, it is preferable that the dispersion of the release agent particles is obtained by dispersing the release agent and the aqueous medium using a disperser in the presence of a surfactant at a temperature equal to or higher than the melting point of the release agent. . As the disperser to be used, a homogenizer, an ultrasonic disperser or the like is preferable.
The aqueous medium and surfactant used in the present production are preferably those used when obtaining the colored resin particles (A), and the aqueous medium is preferably composed mainly of water. The content of water in the aqueous medium is preferably 90% by weight or more, more preferably 95% by weight or more, and still more preferably substantially 100% by weight from the viewpoint of obtaining stable release agent particles. The water used is preferably deionized water or distilled water. Further, as the surfactant, an anionic surfactant is preferable, and dipotassium alkenyl succinate is more preferable.

[Flocculant]
The flocculant used in the present invention comprises an electrolyte. An agglomerated particle dispersion can be efficiently obtained by mixing an aggregating agent made of an electrolyte with colored particles and releasing agent particles in an aqueous medium.
Examples of the electrolyte constituting the flocculant used in the present invention include cationic surfactants such as quaternary ammonium salts, inorganic salts such as inorganic metal salts and inorganic ammonium salts, and inorganic flocculants such as metal complexes. It is done. The cation valence of the electrolyte may be 1 or more, but is preferably 1 or 2, more preferably 1.
Examples of the inorganic salt include an inorganic salt having a cation valence of 1 and an inorganic salt having a cation valence of 2 or more. The aggregation property can be easily adjusted, and the storage stability and durability of the resulting toner can be adjusted. From the viewpoint of improving the above, an inorganic salt having a cation valence of 1 is preferred.
Examples of the inorganic salt having a cation valence of 1 include inorganic sodium salts such as sodium sulfate and sodium chloride; inorganic ammonium salts such as ammonium sulfate, ammonium chloride and ammonium nitrate. From the above viewpoint, inorganic ammonium salts are preferred, and ammonium sulfate. Is more preferable.
Examples of the inorganic salt having a cation valence of 2 or more include calcium salts such as calcium chloride and calcium nitrate; aluminum salts such as aluminum chloride, polyaluminum chloride and polyaluminum hydroxide.

[Resin Particles Containing Polyester Resin (c) (C)]
In the present invention, the resin particles (C) containing the polyester resin (c) (hereinafter also simply referred to as “resin particles (C)”) are produced from the polyester resin (c) from the viewpoint of storage stability and durability of the toner. Containing.
The glass transition point of the resin particle (C) is appropriately determined depending on the glass transition point of the resin such as the polyester resin (c) constituting the resin particle (C) and the kind and amount of the additive. From the viewpoint of low-temperature fixability and storage stability, it is preferably 55 ° C. or higher, more preferably 55 to 75 ° C., still more preferably 55 to 70 ° C., still more preferably 55 to 65 ° C.

The content of the polyester resin (c) in the resin particles (C) is preferably 70% by weight or more, more preferably 80% by weight or more, and further preferably 90 to 100%, from the viewpoint of storage stability and durability of the toner. % By weight, more preferably 95 to 100% by weight, still more preferably substantially 100% by weight.
The resin particles (C) contain, in addition to the polyester resin (c), known resins usually used for toners, for example, crystalline polyester, styrene acrylic copolymer, epoxy resin, polycarbonate, polyurethane and the like. Also good.
The resin particles (C) can be obtained by the same method as the method for producing the colored resin particles (A) described later, and the same alkaline aqueous solution, surfactant and aqueous medium can be suitably used.

(Polyester resin (c))
In the present invention, the polyester resin (c) is preferably an amorphous polyester having a crystallinity index of more than 1.4 or less than 0.6.
From the viewpoint of storage stability and durability of the toner, the crystallinity index of the polyester resin (c) is preferably less than 0.6 or more than 1.4 and less than 4, more preferably less than 0.6 or 1.5 or more. It is 4 or less, more preferably less than 0.6 or 1.5 or more and 3 or less, more preferably less than 0.6 or 1.5 or more and 2 or less. The crystallinity index can be appropriately determined depending on the type and ratio of raw material monomers, production conditions (eg, reaction temperature, reaction time, cooling rate), and the like.

The polyester resin (c) is preferably an amorphous polyester having an acid group at the molecular end. Examples of the acid group include a carboxyl group, a sulfonic acid group, a phosphonic acid group, and a sulfinic acid. Among these, a carboxyl group is preferable from the viewpoint of promoting emulsification of the polyester.
The acid value of the polyester resin (c) is preferably 6 to 35 mgKOH / g, more preferably 10 to 35 mgKOH / g, and still more preferably 15 to 35 mgKOH / g, from the viewpoint of emulsification in the aqueous medium of the resin.
The number average molecular weight of the polyester resin (c) is preferably 1,000 to 50,000, more preferably 1,000 to 10,000, and still more preferably, from the viewpoints of toner durability, low-temperature fixability and storage stability. Is 2,000 to 8,000.

The glass transition point of the polyester resin (c) is preferably 55 to 75 ° C., more preferably 55 to 70 ° C., and still more preferably 58 to 68 ° C. from the viewpoint of toner durability, low-temperature fixability and storage stability. is there.
The softening point of the polyester resin (c) is preferably 70 to 165 ° C, more preferably 70 to 140 ° C, still more preferably 90 to 140 ° C, from the viewpoint of toner durability, low-temperature fixability and storage stability. Preferably it is 100-130 degreeC.
In addition, when using 2 or more types of polyester resin (c) in mixture, the glass transition point and the softening point were obtained by the method of an Example description as a mixture of 2 or more types of polyester resins (c), respectively. It refers to the glass transition point and softening point.
As above-mentioned, it is preferable that the glass transition point of a polyester resin (c), a softening point, a number average molecular weight, and an acid value are the same as the suitable range of a polyester resin (b).

The polyester resin (c) can be produced by subjecting an acid component and an alcohol component to a polycondensation reaction in the same manner as the polyester resin (a).
Examples of the acid component include a dicarboxylic acid, a succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, and a polyvalent carboxylic acid having 3 or more valences. Anhydrides and alkyl (C1-C3) esters are also included. Of these, dicarboxylic acids are preferred.
Dicarboxylic acids include dicarboxylic acids containing aromatic rings such as phthalic acid, isophthalic acid, and terephthalic acid, and aliphatic dicarboxylic acids such as sebacic acid, fumaric acid, maleic acid, adipic acid, azelaic acid, succinic acid, and cyclohexanedicarboxylic acid. Examples include acids, and among these, terephthalic acid is preferable.
Examples of the succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid.
Examples of the trivalent or higher polyvalent carboxylic acid include trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid and the like. Among these, trimellitic acid is preferable from the viewpoint of offset resistance.
These acid components can be used alone or in combination of two or more.
The polyester resin (c) uses at least one amorphous polyester obtained using an acid component containing a trivalent or higher polyvalent carboxylic acid, preferably trimellitic acid, from the viewpoint of offset resistance of the toner. It is preferable to do.

As an alcohol component, the thing similar to the said alcohol component used for the polyester resin (b) is mentioned. Among these, from the viewpoint of obtaining amorphous polyester, aromatic diols are preferable, and polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene-2,2-bis (4-hydroxy). More preferred are alkylene (carbon number 2-3) oxide adducts (average number of added moles 1-16) of bisphenol A such as phenyl) propane.
These alcohol components can be used alone or in combination of two or more.

  The polyester resin (c) preferably contains two kinds of polyesters having different softening points from the viewpoint of low-temperature fixability, offset resistance and durability of the toner. When two types of polyesters having different softening points are respectively used as polyesters (c-1) and (c-2), the softening point of one polyester (c-1) is preferably 70 ° C. or higher and lower than 115 ° C., and the other The softening point of the polyester (c-2) is preferably 115 ° C or higher and 165 ° C or lower. The weight ratio of polyester (c-1) to polyester (c-2) ((c-1) / (c-2)) is preferably 10/90 to 90/10, more preferably 50/50 to 90. / 10.

  In addition, in this invention, what modified | denatured each of polyester resin (a), (b) and (c) can be used in the range which does not impair the effect. Examples of methods for modifying the polyester include grafting with phenol, urethane, epoxy, etc. by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, and the like. Examples thereof include a method of forming a block and a method of forming a composite resin having two or more resin units including a polyester unit.

（式中、Ｍはバリウム、カルシウム、ストロンチウム又はマンガンを表す。） Next, each step in the method for producing an electrophotographic toner of the present invention will be described.
[Step (1)]
Step (1): A step of obtaining a colored resin by melt-mixing the polyester resin (a) and a pigment represented by the following formula.

(In the formula, M represents barium, calcium, strontium or manganese.)

In this step, the polyester resin (a) and the pigment are melt-mixed, that is, the pigment is mixed in a molten state. In this step, the resin is melted and then melted. And the pigment may be mixed, or the resin and the pigment before melting may be pre-blended and mixed while melting the resin. It is preferable to blend the resin and the pigment in advance and mix while melting the resin from the viewpoint of uniformly including the pigment in the resin. For example, a powdery polyester resin (a) and a magenta pigment paste wetted in water are blended. As an apparatus used for blending, a Henschel mixer can be suitably used.
The content of the pigment in the magenta pigment paste is preferably 10 to 60% by weight, more preferably 20 to 50% by weight, and still more preferably 25 to 45% by weight from the viewpoint of good dispersion when mixed in the resin.

As a method for melting the polyester resin and mixing the pigment, it is preferable to mix the pigment by melting the resin at a temperature equal to or higher than the softening point of the polyester resin.
The temperature for melting and mixing is preferably a temperature equal to or higher than the softening point of the polyester resin, specifically, preferably 80 to 180 ° C, more preferably 90 to 150 ° C, and still more preferably 95 to 130 ° C.
In addition, when using a pigment paste, it is preferable to mix at 100 degrees C or less until a water | moisture content evaporates, and to mix at the temperature exceeding 100 degreeC after a water | moisture content evaporates.
Although there is no restriction | limiting in particular in the time to melt-mix, From a viewpoint of preventing modification | denaturation of a pigment and maintaining the viscosity of resin, 10 to 120 minutes are preferable, 20 to 100 minutes are more preferable, and 30 to 60 minutes are still more preferable.

The weight ratio of the pigment to the polyester resin (a) in this step is 0.2 to 1.0 from the viewpoint of improving the image density of the obtained toner while maintaining stable dispersibility in the subsequent step. More preferably, 0.3 to 0.7 is more preferable, and 0.4 to 0.5 is still more preferable.
Although there is no restriction | limiting in particular in the apparatus to melt-mix, A kneader mixer and a heating three roll are used preferably. When a magenta pigment paste wetted in water is used as the pigment, it is preferable to melt and mix until moisture is removed.
The colored resin thus obtained is preferably cooled in order to facilitate use in a subsequent step, and more preferably pulverized into powder or pellets.
The amount of the pigment in the colored resin obtained in this step is preferably 5 to 60% by weight from the viewpoint of improving the image density of the obtained toner while maintaining stable dispersibility in the subsequent step. 50 weight% is more preferable and 20-40 weight% is still more preferable.

[Step (2)]
Step (2) is a step of obtaining colored resin particles (A) by melt-mixing the colored resin and the polyester resin (b) in the presence of an aqueous liquid having a pH of 7 to 11 and then emulsifying them.
The colored resin particles (A) are preferably produced by a method in which a resin containing the polyester resin (b) and optional components described below are dispersed in an aqueous medium to obtain a dispersion containing the colored resin particles (A).
Examples of a method for obtaining a dispersion include a method in which a resin or the like is added to an aqueous medium and subjected to a dispersion treatment with a disperser or the like, and a method in which an aqueous medium is gradually added to the resin or the like to perform phase inversion emulsification. From the viewpoint of low-temperature fixability of the obtained toner, a method by phase inversion emulsification is preferred. Hereinafter, a method by phase inversion emulsification will be described.

First, the colored resin, the polyester resin (b), an aqueous liquid having a pH of 7 to 11 and optional components described later are melted and mixed to obtain a resin mixture. The melt mixing in this step is preferably performed in the presence of a salt of a polybasic acid, and it is preferable to melt and mix the polybasic acid salt as an aqueous solution as an aqueous liquid having a pH of 7 to 11.
When the polyester resin (b) is composed of a plurality of resins, a mixture of the resins may be used in advance, but an aqueous liquid having a pH of 7 to 11, preferably an aqueous solution of the polybasic acid salt, and any It may be obtained by adding the components at the same time when adding the components, and melting and mixing them.
In mixing, it is preferable to add a surfactant from the viewpoint of the emulsion stability of the resin.

Examples of surfactants include nonionic surfactants, anionic surfactants, and cationic surfactants. Among these, nonionic surfactants are preferred, and nonionic surfactants and anionic surfactants are preferred. It is more preferable to use a surfactant or a cationic surfactant in combination, and it is more preferable to use a nonionic surfactant and an anionic surfactant in combination from the viewpoint of sufficiently emulsifying the resin.
When a nonionic surfactant and an anionic surfactant are used in combination, the weight ratio of the nonionic surfactant to the anionic surfactant (nonionic surfactant / anionic surfactant) is: From the viewpoint of sufficiently emulsifying the resin, it is preferably 0.3 to 10, more preferably 0.5 to 5.

Nonionic surfactants include polyoxyethylene nonyl phenyl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl aryl ethers such as polyoxyethylene lauryl ether, polyoxyethylene alkyl ethers, polyethylene glycol monolaurate , Polyoxyethylene fatty acid esters such as polyethylene glycol monostearate and polyethylene glycol monooleate, and oxyethylene / oxypropylene block copolymers. Among these, from the viewpoint of emulsion stability of the resin, polyoxyethylene Alkyl ethers are preferred.
Examples of the anionic surfactant include dodecyl benzene sulfonic acid, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium alkyl ether sulfate, and dipotassium alkenyl succinate. Among these, from the viewpoint of emulsion stability of the resin, dodecyl Sodium benzenesulfonate and sodium alkyl ether sulfate are preferred.
Examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like.

  The content of the surfactant is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, still more preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the resin constituting the resin particles (A). More preferably, it is 0.5 to 10 parts by weight.

As a method for obtaining a resin mixture, the colored resin, the polyester resin (b), the aqueous liquid having a pH of 7 to 11 and the above optional component, preferably a surfactant, are placed in a container, and the resin is stirred while stirring with a stirrer. A method of melting and mixing uniformly is preferable.
The temperature at which the resin is melted and mixed is preferably equal to or higher than the glass transition point of the polyester resin (b).

Next, the resin mixture and the aqueous medium are mixed and emulsified to obtain a dispersion containing the resin particles (A). In particular, the aqueous medium is added to the resin mixture, and the phase is changed. It is preferable to obtain a dispersion containing the particles (A).
As the aqueous medium, those containing water as a main component are preferable. From the viewpoint of obtaining stable resin particles, the content of water in the aqueous medium is preferably 80% by weight or more, more preferably 90% by weight or more, and still more preferably. Is 95% by weight or more, more preferably substantially 100% by weight. The water used is preferably deionized water or distilled water.
As components other than water, organic solvents that dissolve in water such as alkyl alcohols having 1 to 5 carbon atoms; dialkyl (carbon numbers 1 to 3) ketones such as acetone and methyl ethyl ketone; and cyclic ethers such as tetrahydrofuran are used. Among these, from the viewpoint of preventing mixing into the toner, an alkyl alcohol having 1 to 5 carbon atoms that does not dissolve the polyester is preferable, and methanol, ethanol, isopropanol, and butanol are more preferable.

When a dispersion is obtained by phase inversion, the temperature at which the aqueous medium is added is preferably equal to or higher than the glass transition point of the polyester resin (b).
The addition rate of the aqueous medium is preferably 0.1 to 100 parts by weight of the resin constituting the resin particles (A) until the phase inversion is completed from the viewpoint of making the resin particles have a small particle size. 50 parts by weight / minute, more preferably 0.1 to 30 parts by weight / minute, still more preferably 0.5 to 10 parts by weight / minute, still more preferably 0.5 to 5 parts by weight / minute. In addition, there is no restriction | limiting in the addition rate of the aqueous medium after completion | finish of phase inversion.

The amount of the aqueous medium used is preferably 100 to 2000 parts by weight, more preferably 150 to 100 parts by weight with respect to 100 parts by weight of the resin constituting the resin particles (A) from the viewpoint of obtaining uniform aggregated particles in the subsequent aggregation step. 1500 parts by weight, more preferably 150 to 500 parts by weight.
The solid content concentration is preferably 7 to 50% by weight, more preferably 10 to 40% by weight, still more preferably 20 to 40% by weight, from the viewpoint of the stability and ease of handling of the obtained resin particle dispersion. More preferably, it is 25 to 35% by weight. In addition, solid content is the total amount of non-volatile components, such as resin and surfactant.

The volume median particle size of the resin particles (A) in the dispersion containing the obtained resin particles (A) is preferably from 0.02 to 2 μm, more preferably from the viewpoint of obtaining a high-image toner. It is 02-1.5 micrometers, More preferably, it is 0.05-1 micrometer, More preferably, it is 0.05-0.5 micrometer. Here, the volume-median particle size is a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% calculated from the smaller particle size.
The coefficient of variation (CV value) (%) of the particle size distribution of the resin particles is preferably 40% or less, more preferably 35% or less, still more preferably 30% or less, and still more preferably, from the viewpoint of obtaining a high-image toner. Is 28% or less.

The pigment content in the obtained colored resin particles (A) is preferably 1 to 20 with respect to 100 parts by weight of the resin constituting the colorant-containing resin particles (A) from the viewpoint of the image density of the toner. Parts by weight, more preferably 3 to 15 parts by weight, still more preferably 5 to 10 parts by weight.
The total amount of the polyester resin (a) and the polyester resin (b) in the colored resin particles (A) is the resin particles (A) from the viewpoint of improving storage stability and durability while maintaining the low-temperature fixability of the toner. Is preferably 50 to 100% by weight, more preferably 80 to 100% by weight, still more preferably 90 to 100% by weight, and still more preferably substantially 100% by weight.

The resin particle (A) is a resin other than the polyester resin (a) and the polyester resin (b), for example, a resin such as a styrene acrylic copolymer, an epoxy resin, a polycarbonate, and a polyurethane as long as the effects of the present invention are not impaired. You may contain.
In addition, the resin particles (A) may contain a release agent and a charge control agent as long as the effects of the present invention are not impaired. If necessary, reinforcing fillers such as fibrous substances, antioxidants, and the like. You may contain additives, such as an agent and an antioxidant.

[Step (3)]
Step (3) is a step of aggregating and fusing the colored resin particles (A), and there is no particular limitation on the method thereof, but it may include the following steps (3-1) to (3-3). preferable.
Step (3-1): Step of obtaining the aggregated particle dispersion (1) by mixing the colored resin particles (A), the release agent particles, and the flocculant in an aqueous medium Step (3-2): Aggregated particles Step of obtaining aggregated particle dispersion (2) by adding resin particles (C) containing polyester resin (c) to dispersion (1) Step (3-3): Aggregated particle dispersion (2) Fusion process

[Step (3-1)]
Step (3-1) is a step of obtaining the aggregated particle dispersion (1) by mixing the colored resin particles (A), the release agent particles, and the flocculant in an aqueous medium.
In this step, the method for obtaining the agglomerated particle dispersion (1) is not limited, but the agglomerated particle dispersion is obtained by mixing the colored resin particles (A), the release agent particles, and the aggregating agent in an aqueous medium. Is preferred. There is no restriction on the order of mixing, and either of them may be added in order or at the same time, but from the viewpoint of efficiently obtaining an aggregated particle dispersion, the colored resin particles and the release agent particles are added. It is preferable to mix the flocculant after mixing. Hereinafter, a method of mixing in this order will be described.

In this step, first, the colored resin particles and the release agent particles are mixed in an aqueous medium to obtain a mixed dispersion.
In the step (3-1), the colored resin particles (A) may be mixed, or resin particles other than the resin particles (A) may be mixed. The resin particles other than the resin particles (A) are preferably resin particles containing amorphous polyester from the viewpoint of improving the storage stability of the toner, and the resin particles having the same components as the resin particles (C) described above. More preferably, the same composition ratio is more preferable.
There is no restriction | limiting in order of mixing, You may add any in order and may add simultaneously.

When the colored particles are colored resin particles (A), the content of the resin particles (A) is preferably 10 to 40 parts by weight, more preferably 12 to 35 parts by weight, more preferably in the aggregated particle dispersion. Is 12 to 20 parts by weight. The content of the aqueous medium is preferably 60 to 90 parts by weight, more preferably 70 to 88 parts by weight in the aggregated particle dispersion.
Further, the content of the pigment is preferably 1 to 20 parts by weight, more preferably 3 to 15 parts by weight with respect to 100 parts by weight of the resin constituting the resin particles (A) from the viewpoint of image density.
The content of the release agent particles is preferably 1 to 20 parts by weight, more preferably 2 to 15 parts by weight, based on the total 100 parts by weight of the resin and the colorant, from the viewpoint of toner releasability and chargeability. Part.
The temperature of the mixed dispersion at the time of mixing is preferably 0 to 40 ° C. from the viewpoint of aggregation control.

Next, the flocculant is mixed with the mixed dispersion in an aqueous medium, and the particles in the mixed dispersion are aggregated to obtain a dispersion of aggregated particles.
From the viewpoint of storage stability and durability of the toner, the use amount of the flocculant is, based on 100 parts by weight of the resin constituting the resin particles (A), when the colored particles are the colorant-containing resin particles (A). Preferably it is 50 parts by weight or less, more preferably 40 parts by weight or less, still more preferably 30 parts by weight or less, and preferably 1 part by weight or more, more preferably 3 parts by weight or more from the viewpoint of cohesiveness of the resin particles. More preferably, it is 5 parts by weight or more. Considering the above points, the amount of the flocculant used is preferably 1 to 50 parts by weight, more preferably 3 to 40 parts by weight, and still more preferably 100 parts by weight of the resin constituting the resin particles (A). Is 5 to 30 parts by weight.

  As an aggregating method, it is preferable to add the aggregating agent as an aqueous solution dropwise to a container containing the mixed dispersion. The flocculant may be added at one time, or may be added intermittently or continuously. However, it is preferable to perform sufficient stirring at the time of addition and after completion of the addition. From the viewpoint of controlling aggregation and shortening the toner production time, the dropping time of the aggregating agent is preferably 1 to 120 minutes. The dropping temperature is preferably 0 to 40 ° C. from the viewpoint of controlling aggregation.

  The volume-median particle size of the obtained aggregated particles is preferably 1 to 10 μm, more preferably 2 to 9 μm, and further preferably 3 to 6 μm, from the viewpoint of reducing the reduction in toner particle size. The CV value is preferably 30% or less, more preferably 28% or less, and still more preferably 25% or less.

The concentration of the aggregating agent in the aggregated particle dispersion obtained in the step (3-1) is preferably 0 from the viewpoint of improving the storage stability of the toner when an electrolyte having a cation valence of 1 is used as the aggregating agent. 0.08 to 1.3 mol / L, more preferably 0.1 to 1.1 mol / L, and still more preferably 0.3 to 1.0 mol / L.
The preferred flocculant concentration depends on the valency of the flocculant used. When an electrolyte having a cation valence of 2 or more is used for the aggregating agent, the aggregating agent concentration is z from the viewpoint of obtaining an appropriate aggregating property for obtaining agglomerated particles having the above-mentioned particle diameter. , Preferably 0.08 × z ^{−6 to} 1.3 × z ⁻⁶ mol / L, more preferably 0.1 × z ^{−6 to} 1.1 × z ⁻⁶ mol / L, still more preferably 0.3. × a z ^-6 to 1.0 × z ^-6 mol / L.

As shown in the following formula, the coagulant equivalent is obtained by dividing the product of the cation valence of the coagulant and the number of moles of the coagulant by the number of moles of acid groups (carboxy groups) of the total resin contained in the toner. Is required. The number of moles of acid groups (carboxy groups) in all resins is calculated from the acid values and contents of all resins.
Flocculant equivalent = (valence of cation of flocculant) × (mol number of flocculant) / (mol number of acid groups (carboxy groups) of all resins)
From the viewpoint of improving the storage stability of the toner, the equivalent of the aggregating agent in the aggregated particle dispersion is preferably 5 to 15 equivalents, more preferably 7 to 12 equivalents, and even more preferably 8 to 11 equivalents.

[Step (3-2)]
In step (3-2), resin particles (C) containing a polyester resin (c) are added to the aggregated particle dispersion (1) obtained in step (3-1), and the aggregated particle dispersion ( This is a step of obtaining 2).
In this step, first, a dispersion of resin particles (C) containing a polyester resin (c) (hereinafter also referred to as “resin particle (C) dispersion”) is prepared, and then the resin particles (C) are dispersed. It is preferable to add the liquid to the dispersion liquid of the aggregated particles obtained in the step (3-1) and attach the resin particles (C) to the aggregated particles to obtain core-shell structured particles.
From the viewpoint of more uniformly attaching the resin particles (C) to the aggregated particles, it is preferable to add an aqueous medium to the aggregated particle dispersion and dilute it before adding the resin particle (C) dispersion.
When the resin particle (C) dispersion is added, the aggregating agent may be used to efficiently attach the resin particles (C) to the aggregated particles.
As an addition method when adding the resin particle (C) dispersion, the coagulant and the resin particle (C) dispersion are added simultaneously, and the coagulant and the resin particle (C) dispersion are added alternately. A method, a method of adding the resin particle (C) dispersion while gradually raising the temperature of the core aggregated particle dispersion, and the like are preferable. According to such a method, it is possible to prevent a decrease in the cohesiveness of the aggregated particles and the resin particles (C) due to the decrease in the coagulant concentration. Among these, it is preferable to add the resin particle (C) dispersion while gradually raising the temperature of the aggregated particle dispersion from the viewpoint of toner productivity and manufacturing simplicity.

In step (3-2), the temperature in the system at the time of addition and / or completion of the addition of the resin particle (C) dispersion is less than the melting point of the release agent and the glass transition point of the polyester resin (c). It is preferable that the temperature be 20 ° C. or lower.
By setting the temperature at the time of adding the resin particles (C) to be lower than the melting point of the release agent, the durability and storage stability of the obtained toner can be improved. The reason for this is not clear, but it is also considered that since the core-shell particles are not fused together, the generation of coarse particles is suppressed and the crystallinity of the release agent can be maintained.

  The addition amount of the resin particles (C) is a weight ratio (resin particles (C) / resin particles (C) / resin particles (C) / resin particles (A)) from the viewpoint of low-temperature fixability of the toner, reduction of scattering amount, and storage stability. The amount of the resin particles (A)) is preferably 0.3 to 1.5, more preferably 0.3 to 1.0, and still more preferably 0.35 to 0.75.

The resin particle (C) dispersion may be added continuously over a certain period of time, or may be added at once, or may be added in multiple portions. From the viewpoint of facilitating selective aggregation on the aggregated particles, it is preferably added continuously over a certain period of time or divided into a plurality of times, and among them, the viewpoint of promoting selective aggregation Further, from the viewpoint of production efficiency, it is more preferable to add continuously over a certain time, and when continuously adding, it is further possible to raise the temperature in the system within the above temperature range. preferable.
The addition time in the case of continuous addition is preferably 1 to 10 hours, more preferably 3 to 8 hours, from the viewpoint of obtaining uniform core-shell structure particles and shortening of the production time.

The total amount of the resin particles (C) is added, and the aggregation is stopped when the toner particles grow to an appropriate particle size.
As the particle size for stopping the aggregation, the volume median particle size is preferably 1 to 10 μm, more preferably 2 to 8 μm, still more preferably 3 to 7 μm, and further preferably 4 to 6 μm.
Methods for stopping the aggregation include a method of cooling the dispersion and a method of adding an aggregation terminator. From the viewpoint of reliably preventing unnecessary aggregation, the aggregation is stopped by adding an aggregation terminator. The method of making it preferable is.

As the aggregation terminator, a surfactant is preferable, and an anionic surfactant is more preferable. Examples of the anionic surfactant include alkyl ether sulfates such as sodium alkyl ether sulfate, alkyl sulfates, and linear alkylbenzene sulfonates. The aggregation terminators can be used alone or in combination of two or more.
That is, in this step (3-2), after adding the resin particles (C) to the aggregated particle dispersion, an anionic surfactant as an aggregation terminator is added to the core-shell particle dispersion (1 Is preferred.
The addition amount of the aggregation terminator is preferably 0.1 to 15 parts by weight with respect to 100 parts by weight of the total resin in the system, from the viewpoint of reducing the aggregation terminator and the residual of the aggregation terminator in the toner. Preferably it is 0.1-10 weight part, More preferably, it is 0.1-8 weight part. The aggregation terminator may be added in any form, but is preferably added in an aqueous solution from the viewpoint of productivity.

The concentration of the aggregating agent in the aggregated particle dispersion (2) obtained in the step (3-2) is determined from the viewpoint of improving the storage stability of the toner when an electrolyte having a cation valence of 1 is used as the aggregating agent. Preferably it is 0.05-0.85 mol / L, More preferably, it is 0.10-0.75 mol / L, More preferably, it is 0.20-0.70 mol / L.
The preferred flocculant concentration depends on the valency of the flocculant used. When an electrolyte having a cation valence of 2 or more is used as the aggregating agent, the aggregating agent concentration is z from the viewpoint of obtaining an appropriate aggregating property for obtaining core-shell particles having the above-mentioned particle diameter. , preferably 0.05 × z ^-6 ~0.85 × z ^-6 mol / L, more preferably 0.10 × z ^-6 ~0.75 × z ^-6 mol / L, more preferably 0.20 × a z ^-6 to 0.70 × z ^-6 mol / L.
Further, the equivalent of the aggregating agent in the aggregated particle dispersion (2) obtained from the above formula is preferably 3.3 to 10 equivalents, more preferably 4.7, from the viewpoint of improving the storage stability of the toner. -8 equivalents, more preferably 5.3 to 7.3 equivalents.

[Step (3-3)]
Step (3-3) is a step of fusing the aggregated particle dispersion (2).
Specifically, the resin particles in the aggregated particles are fused by maintaining the aggregated particle dispersion (2) at a certain temperature or higher.

The holding temperature is preferably not higher than the melting point of the release agent, more preferably less than 5 ° C. lower than the melting point of the release agent, more preferably less than 10 ° C. lower than the melting point of the release agent. Durability and storage stability can be improved.
The holding temperature is preferably at least 5 ° C. lower than the glass transition point of the polyester resin (c), more preferably at least 3 ° C. lower than the glass transition point, and even more preferably 2 ° C. lower than the glass transition point. With the above, the fusing property, the storage stability of the toner, the charging property, and the toner productivity can be improved.
By satisfying these conditions, exposure of the release agent to the toner surface that causes a decrease in toner durability and storage stability while maintaining the crystalline state of the release agent that exhibits high fixability at low temperatures Can be suppressed, and the shell portion can be uniformly fused. As a result, it is considered that a toner satisfying all of excellent low-temperature fixability, durability and storage stability can be obtained.
Furthermore, the holding temperature is preferably at least the glass transition point of the resin particles (C), more preferably at least 2 ° C. higher than the glass transition point of the resin particles (C). Storage stability, chargeability and toner productivity can be further improved.
In view of the above points, the holding temperature in the step (3-3) is preferably 58 to 69 ° C, more preferably 59 to 67 ° C, and further preferably 60 to 65 ° C.
In the step (3-3), the holding time at the above temperature is preferably 1 to 24 hours, more preferably 1 to 12 from the viewpoints of particle fusing property, toner storage stability, durability and toner productivity. Time, more preferably 2 to 6 hours.

In the step (3-3), the agglomerated particles are fused to obtain a core-shell particle dispersion.
The concentration of the flocculant in the core-shell particle dispersion is preferably 0.05 to 0.40 mol / L from the viewpoint of improving the storage stability of the toner when an electrolyte having a cation valence of 1 is used as the flocculant. More preferably, it is 0.10-0.30 mol / L, More preferably, it is 0.10-0.20 mol / L.
Further, the concentration of the flocculant in the core-shell particle dispersion after addition of the aqueous solution in this step is 0.65 of the concentration of the flocculant in the core-shell particle dispersion (1) from the viewpoint of improving the storage stability of the toner. It is preferable to be less than double.

  In this step, it is preferable to confirm the progress of fusion by monitoring the circularity of the generated core-shell particles. Circularity is monitored by the method described in the examples. When the circularity reaches 0.920 or more, the cooling is performed and the fusion is stopped. The circularity of the core-shell particles contained in the finally obtained core-shell particle dispersion is preferably 0.920 to 0.970, more preferably 0.930 to 0.00 from the viewpoint of reducing toner scattering. It is 965, More preferably, it is 0.940-0.960.

The volume median particle size of the core-shell particles in the core-shell particle dispersion is preferably 1 to 10 μm, more preferably 2 to 10 μm, still more preferably 3 to 9 μm, and still more preferably, from the viewpoint of improving the image quality of the toner. 4-6 μm.
Further, the ratio of the core-shell particles having a particle size of 2 μm or less is preferably 8.0% or less, more preferably 5.0% or less, and further preferably 3 with respect to the total number of core-shell particles in the core-shell particle dispersion. .5% or less.

[Post-processing process]
In the present invention, a post-treatment step may be performed after step (3), and it is preferable to obtain toner particles by isolating the obtained fused particles, preferably core-shell particles.
Since the fused particles obtained in the step (3) are present in the aqueous medium, it is preferable to first perform solid-liquid separation. For solid-liquid separation, a suction filtration method or the like is preferably used.
In addition, it is preferable to wash after solid-liquid separation. As a cleaning method, for the purpose of ensuring sufficient charging characteristics and reliability as a toner, it is preferable to perform cleaning with an acid in order to remove metal ions on the toner surface. Moreover, since it is preferable to remove the added nonionic surfactant, it is preferable to wash with an aqueous solution below the cloud point of the nonionic surfactant. The washing is preferably performed a plurality of times.
Next, it is preferable to perform drying. As the drying method, a vibration type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method or the like is preferable. The water content after drying is preferably adjusted to 1.5% by weight or less, more preferably 1.0% by weight or less, from the viewpoint of reducing the amount of toner scattered and charging properties.

<Magenta toner for electrophotography>
(Magenta toner)
The particles obtained by drying or the like can be used as they are as the magenta toner of the present invention, but those surface-treated as described below are preferably used as the magenta toner for electrophotography.
The softening point of the obtained toner is preferably 60 to 140 ° C., more preferably 65 to 130 ° C., and still more preferably 70 to 120 ° C., from the viewpoint of low temperature fixability and hot offset resistance of the toner. The glass transition point is preferably 30 to 80 ° C., more preferably 40 to 70 ° C. from the viewpoints of low-temperature fixability, durability, and storage stability.
The circularity of the toner is preferably 0.955 to 0.980, more preferably 0.958 to 0.980, and still more preferably 0.960 to 0, from the viewpoints of storage stability, chargeability and cleaning properties of the toner. .975. The circularity of the toner can be measured by the method described later. The circularity of the toner is a value obtained by the ratio of the circumference of the circle equal to the projected area / the circumference of the projected image. The more circular the particles are, the closer the circularity is to 1.
The volume median particle size of the toner is preferably 1 to 10 μm, more preferably 2 to 8 μm, still more preferably 3 to 7 μm, and still more preferably 4 to 6 μm, from the viewpoint of high image quality and productivity of the toner.
The CV value of the toner is preferably 30% or less, more preferably 27% or less, still more preferably 25% or less, and further preferably 22% or less, from the viewpoint of high image quality and productivity.

(External additive)
In the electrophotographic magenta toner of the present invention, the toner particles can be used as the toner as they are, but it is preferable to use a toner obtained by adding a fluidizing agent or the like to the toner particle surface as an external additive. External additives include hydrophobic fine particles such as hydrophobic silica, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles, inorganic fine particles such as carbon black, acrylic resin such as polycarbonate and polymethyl methacrylate, and polymer fine particles such as silicone resin. Among these, polymer fine particles and hydrophobic silica are preferable, and hydrophobic silica is more preferable.
When the surface treatment of the toner particles is performed using the external additive, the amount of the external additive added is preferably 1 to 10 parts by weight, more preferably 100 parts by weight of the toner particles before the treatment with the external additive. 2 to 8 parts by weight, more preferably 3 to 6 parts by weight.
The electrophotographic toner obtained by the present invention can be used as a one-component developer or as a two-component developer mixed with a carrier.

Each property value of polyester, resin particles, toner, etc. was measured and evaluated by the following method.
[Acid value of polyester]
It measured according to JIS K0070. However, the measurement solvent was chloroform.

[Polyester softening point, endothermic maximum peak temperature, melting point and glass transition point]
(1) Softening point Using a flow tester (manufactured by Shimadzu Corporation, trade name: CFT-500D), a load of 1.96 MPa was applied by a plunger while heating a 1 g sample at a heating rate of 6 ° C / min. And extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The amount of flow tester drop by the flow tester was plotted against the temperature, and the temperature at which half the sample flowed out was taken as the softening point.
(2) Endothermic maximum peak temperature, melting point and glass transition point Using a differential scanning calorimeter (manufactured by PerkinElmer, trade name: Pyris 6 DSC), the temperature is raised to 200 ° C., and the temperature lowering rate is 50 ° C./min. The sample cooled to 0 ° C. was measured at a heating rate of 10 ° C./min. Of the endothermic peaks observed, the peak temperature having the maximum peak area was defined as the maximum endothermic peak temperature. In the case of crystalline polyester, the peak temperature was taken as the melting point. In the case of an amorphous polyester, when an endothermic peak is observed, the temperature of the peak is measured, and when a step is observed without a peak being observed, the tangent indicating the maximum slope of the curve of the step and the step The glass transition point was defined as the temperature at the intersection with the base line extension line on the high temperature side.

[Glass transition point of resin particles]
First, the solvent was removed from the resin particle dispersion by freeze-drying to obtain a solid.
The lyophilization of the resin particle dispersion was carried out using a freeze dryer (manufactured by Tokyo Rika Kikai Co., Ltd., trade names: FDU-2100 and DRC-1000) with 30 g of the resin particle dispersion at −25 ° C. for 1 hour. Vacuum drying was performed at −10 ° C. for 10 hours and at 25 ° C. for 4 hours, and the moisture content was dried to 1% by weight or less. The moisture content was determined by using an infrared moisture meter (trade name: FD-230, manufactured by Kett Scientific Laboratory), drying 5 g of the sample at a drying temperature of 150 ° C. and a measurement mode 96 (monitoring time 2.5 minutes). / Fluctuation range 0.05%).
About the solid substance obtained after removing a solvent, the glass transition point of the resin particle was measured by the method similar to the measuring method of the glass transition point of the above-mentioned polyester.

[Number average molecular weight of polyester]
The molecular weight distribution was measured by gel permeation chromatography and the number average molecular weight was calculated by the following method.
(1) Preparation of sample solution Polyester was dissolved in chloroform so that the concentration was 0.5 g / 100 ml. Subsequently, this solution was filtered using a fluororesin filter having a pore size of 2 μm (manufactured by Sumitomo Electric Industries, Ltd., trade name: FP-200) to remove insoluble components to obtain a sample solution.
(2) Molecular weight distribution measurement Chloroform was allowed to flow as a lysis solution at a flow rate of 1 ml / min, and the column was stabilized in a constant temperature bath at 40 ° C. Measurement was performed by injecting 100 μl of the sample solution. The molecular weight of the sample was calculated based on a calibration curve prepared in advance. The calibration curve at this time includes several types of monodisperse polystyrene (monodisperse polystyrene manufactured by Tosoh Corporation; 2.63 × 10 ³ , 2.06 × 10 ⁴ , 1.02 × 10 ⁵ (weight average molecular weight), A monodisperse polystyrene manufactured by GL Sciences Inc .; 2.10 × 10 ³ , 7.00 × 10 ³ , 5.04 × 10 ⁴ (weight average molecular weight)) was used as a standard sample.
Measuring device: CO-8010 (trade name, manufactured by Tosoh Corporation)
Analytical column: GMHXL + G3000HXL (both trade names, manufactured by Tosoh Corporation)

[Volume Median Particle Size (D ₅₀ ) and Particle Size Distribution of Colored Particles, Resin Particles, and Release Agent Particles]
(1) Measuring device: Laser diffraction particle size measuring machine (Horiba, Ltd., trade name: LA-920)
(2) Measurement conditions: Distilled water was added to the measurement cell, and the volume-median particle size (D ₅₀ ) was measured at a temperature at which the absorbance falls within an appropriate range. The CV value was calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution / volume median particle size (D ₅₀ )) × 100

[Solid content concentration of colored particles and resin particle dispersion]
Using an infrared moisture meter (trade name: FD-230, manufactured by Ketto Scientific Laboratory Co., Ltd.), 5 g of colored particles or resin particle dispersion was measured at a drying temperature of 150 ° C., measurement mode 96 (monitoring time 2.5 minutes / variation) The moisture% was measured at a width of 0.05%. The solid content concentration was calculated according to the following formula.
Solid content concentration (% by weight) = 100-M
M: moisture (%) = [(W−W ₀ ) / W] × 100
W: Sample weight before measurement (initial sample weight)
W ₀ : Sample weight after measurement (absolute dry weight)

[Volume-median particle size (D ₅₀ ) of toner (particles), aggregated particles, number% of particle size of 2 μm or less, and particle size distribution]
The volume median particle size of the toner (particles) was measured as follows.
Measuring instrument: Coulter Multisizer III (trade name, manufactured by Beckman Coulter)
・ Aperture diameter: 50μm
・ Analysis software: Multisizer III version 3.51 (trade name, manufactured by Beckman Coulter)
Electrolyte: Isoton II (trade name, manufactured by Beckman Coulter)
Dispersion: Polyoxyethylene lauryl ether (trade name, Emulgen 109P, HLB: 13.6, manufactured by Kao Corporation) was dissolved in the electrolytic solution to obtain a dispersion having a concentration of 5% by weight.
-Dispersion condition: 10 mg of a toner measurement sample is added to 5 mL of the dispersion, and dispersed for 1 minute with an ultrasonic disperser, and then 25 mL of electrolyte is added, and further dispersed for 1 minute with an ultrasonic disperser. A sample dispersion was prepared.
Measurement conditions: The sample dispersion is added to 100 mL of the electrolytic solution to adjust the particle size of 30,000 particles to a concentration that can be measured in 20 seconds, and then 30,000 particles are measured and the particle size distribution thereof. The volume-median particle size (D ₅₀ ) and the number percent of the particle size of 2 μm or less were determined.
The CV value (%) was calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution / volume median particle size (D ₅₀ )) × 100
The volume-median particle size of the agglomerated particles and the core-shell agglomerated particles was measured in the same manner by using an agglomerated particle dispersion as a sample dispersion in the measurement of the volume-median particle size of the toner (particles).

[Core shell particle, toner circularity]
-Preparation of dispersion: The dispersion of core-shell particles was diluted with deionized water so that the solid content concentration of the core-shell particles was 0.001 to 0.05%, and used as a sample dispersion. The toner dispersion was prepared by adding 50 mg of toner to 5 ml of an aqueous solution of 5% by weight polyoxyethylene lauryl ether (trade name, Emulgen 109P, manufactured by Kao Corporation), and dispersing for 1 minute with an ultrasonic disperser. Then, 20 ml of distilled water was added, and further dispersed for 1 minute with an ultrasonic disperser to obtain a toner dispersion.
Measurement device: Flow-type particle image analyzer (manufactured by Sysmex Corporation, trade name: FPIA-3000)
・ Measurement mode: HPF measurement mode

[Image density]
Using a commercially available printer (trade name: ML5400, manufactured by Oki Data Co., Ltd.) on high-quality paper (Fuji Xerox Co., Ltd., J paper A4 size), the toner adhesion amount on the paper is 0.42 to 0.48 mg. A solid image of / cm ² was output to obtain a printed matter.
30 sheets of high-quality paper (Oki Data Co., Ltd., Excellent White Paper A4 size) are laid under the printed material, and the reflected image density of the fixed image portion before and after peeling the tape of each printed material is measured by a colorimeter (trade name) : SpectroEye, manufactured by GretagMacbeth, Inc., light emission conditions: standard light source D ₅₀ , observation field of view 2 °, density standard DINNB, absolute white standard). The larger the value of the reflected image density, the better the image density.

[Toner fixability evaluation]
Using a commercially available printer (trade name: ML5400, manufactured by Oki Data Co., Ltd.), in which high-quality paper (manufactured by Fuji Xerox Co., Ltd., J paper A4 size) was loaded with the toner obtained in the examples and comparative examples. A solid image in which the toner adhesion amount on the paper is 0.45 ± 0.03 mg / cm ² is left as an unfixed image with a length of 50 mm, leaving a margin of 5 mm from the top edge of the A4 paper. . The fixing device mounted on the printer was modified to have a variable temperature, and fixed at a temperature fixing speed of 34 sheets / minute (A4 vertical direction). The fixability of the obtained fixed image was evaluated by the following tape peeling method, and the fixable temperature range was measured.

(Tape peeling method)
After cutting a mending tape (product name: Scotch Mending Tape 810, width 18 mm) to a length of 50 mm and affixing it lightly on the margin at the top of the fixed image, 500 g, bottom area 19.6 cm ^Two weights were placed and pressed once back and forth at a speed of 10 mm / sec. Thereafter, the applied tape is peeled off from the lower end side at a peeling angle of 180 degrees and at a speed of 10 mm / sec, and the reflected image density before and after the tape application is measured by a colorimeter (manufactured by GretagMacbeth, trade name: SpectroEye, lighting conditions; standard light source). D50, observation field of view 2 °, density standard DINNB, absolute white standard), and the fixing ratio was calculated from the following formula.
Fixing rate (%) = (image density after tape peeling / image density before tape application) × 100
When the image density after peeling becomes the same value as the image density before applying the tape, the fixing rate is 100%, and as the value decreases, the fixability is low. A fixing rate of 90% or more is determined to be good fixability.

(Fixable temperature range)
The fixability test by the tape peeling method was performed at each fixing temperature in increments of 5 ° C., and the test was performed from a temperature at which a cold offset occurs or a temperature at which the fixing rate is less than 90% to a temperature at which a hot offset occurs. The cold offset is a phenomenon in which the toner on the unfixed image is not sufficiently melted and the toner adheres to the fixing roller when the fixing temperature is low. On the other hand, the hot offset is a temperature at which the fixing temperature is increased. In this case, the phenomenon is that the toner adheres to the fixing roller due to a decrease in the viscoelasticity of the toner on the unfixed image. The occurrence of cold offset or hot offset can be judged by whether or not toner adheres to the paper again when the fixing roller makes one round. In this test, whether toner adheres to the area 87 mm from the top of the solid image. Judged by no.
The toner fixability in the present invention was evaluated based on the minimum fixing temperature and the toner fixing temperature range (minimum fixing temperature to maximum fixing temperature). The wider the fixable temperature range, the better the fixing property, and the lower the minimum fixing temperature, the better the low temperature fixing property. Here, the minimum fixing temperature refers to the minimum temperature among the temperatures at which cold offset does not occur or the fixing rate is 90% or more, and the maximum fixing temperature is the temperature at which the hot offset occurs at −5 ° C. Say. The hot offset generation temperature is a temperature at which hot offset starts to occur.

Production Example 1
(Production of polyester resin (A))
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3374 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane (33 g), terephthalic acid (672 g) and dibutyltin oxide (10 g) were added, and the temperature was raised to 230 ° C. with stirring in a nitrogen atmosphere. After maintaining the time, the pressure in the flask was further reduced and maintained at 8.3 kPa for 1 hour. Then, after cooling to 210 ° C. and returning to atmospheric pressure, 696 g of fumaric acid and 0.49 g of tert-butylcatechol were added and maintained at a temperature of 210 ° C. for 5 hours. The polyester resin (A) was obtained by maintaining at 3 kPa for 4 hours. The glass transition point was 65 ° C., the softening point was 107 ° C., and the crystallinity index was 1.5. The acid value was 24.4 mgKOH / g, and the number average molecular weight was 3.0 × 10 ³ .

Production Example 2
(Manufacture of polyester resin (B))
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 1750 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, A nitrogen atmosphere containing 1625 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1145 g of terephthalic acid, 161 g of dodecenyl succinic anhydride, 480 g of trimellitic anhydride, and 10 g of dibutyltin oxide Under stirring, the temperature was raised to 220 ° C. and maintained at 220 ° C. for 5 hours. After confirming that the softening point measured according to ASTM D36-86 reached 120 ° C., the temperature was lowered to stop the reaction. A polyester resin (B) was obtained. The glass transition point was 65 ° C., the softening point was 122 ° C., and the crystallinity index was 1.6. The acid value was 21.0 mgKOH / g, and the number average molecular weight was 2.9 × 10 ³ .

Production Example 3
(Manufacture of polyester resin (C))
Four-neck equipped with 3490 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 5800 g of fumaric acid and 15 g of dibutyltin oxide, equipped with a nitrogen inlet tube, dehydration tube, stirrer and thermocouple It put into the flask, it stirred at 230 degreeC under nitrogen atmosphere, and it was made to react until the softening point measured according to ASTM D36-86 reached 100 degreeC, and polyester resin (C) was obtained. The softening point of the polyester resin (C) was 98 ° C., the glass transition point was 56 ° C., the acid value was 22.4 mgKOH / g, and the number average molecular weight was 2.9 × 10 ³ .

Production Example 4
(Preparation of aqueous solution containing polybasic acid salt)
50 g of potassium hydroxide was dissolved in 200 g of deionized water to prepare a 20 wt% aqueous potassium hydroxide solution. The potassium hydroxide aqueous solution is placed in a 1 L beaker, and while stirring with a magnetic stirrer, phosphoric acid is added to adjust to pH 8.2, and then 10 weight in terms of potassium hydroxide while adding ion-exchanged water and phosphoric acid. A pH 8.0 aqueous solution containing 1% potassium phosphate salt was obtained. The pH is a value after maintaining the solution at 25 ° C. and holding for 3 minutes with a pH meter.
Similarly, an aqueous solution (10 wt% in terms of potassium hydroxide) containing a potassium salt of phosphoric acid having a pH of 10 was prepared.

Production Example 5
(Production of release agent particle dispersion)
In a beaker having an internal volume of 1 liter, 480 g of deionized water, 4.29 g of an alkenyl (mixture of hexadecenyl group and octadecenyl group) dipotassium succinate solution (trade name: Latemul ASK, effective concentration 28% by weight, manufactured by Kao Corporation), 120 g of carnauba wax (produced by Hiroyuki Kato, melting point 85 ° C., acid value 5 mgKOH / g) was added and stirred. While maintaining the mixed liquid at 90 to 95 ° C., it was subjected to a dispersion treatment for 30 minutes using an ultrasonic disperser (trade name: Ultrasonic Homogenizer 600W, manufactured by Nippon Seiki Seisakusho Co., Ltd.) and then cooled to 25 ° C. Then, deionized water was added to adjust the solid content to 20% by weight to obtain a release agent particle dispersion. The volume median particle size of the release agent particles was 0.494 nm, and the CV value was 34%.

Production Example 6
(Production of resin particle dispersion (B))
In a reaction vessel having an internal volume of 5 liters, in a flask, 390 g of polyester resin (A), 210 g of polyester (B), polyoxyethylene alkyl ether (trade name: Emulgen 430, nonionic surfactant) manufactured by Kao Corporation 6 g, 15 wt% sodium dodecylbenzenesulfonate aqueous solution (trade name: Neoperex G-15, anionic surfactant) 40 g and 10 wt% potassium hydroxide 134 g and deionized water 134 g, While stirring, the mixture was heated to 95 ° C. to melt and mixed at 95 ° C. for 2 hours to obtain a resin mixture.
Next, 1145 g of deionized water was added dropwise at a rate of 6 g / min while stirring to obtain an emulsion. Next, the obtained emulsion was cooled to 25 ° C., passed through a 200-mesh wire mesh, deionized water was added to adjust the solid content to 23% by weight, and a resin particle dispersion (B) was obtained. . The volume median particle size of the resin particles (B) in the dispersion (B) was 0.158 μm, the CV value was 24%, and the glass transition point was 60 ° C.

Example 1
(Manufacture of magenta toner (A))
(1) Production of colored resin A (step (1))
70. 5 parts by weight of fine powder of polyester resin (C) of Production Example 3 and paste-like magenta pigment (Pigment Red 48: 3, manufactured by Dainichi Seika Kogyo Co., Ltd., solid concentration 31.4% by weight) 95.54 weight Parts (30 parts by weight in terms of pigment content) were charged into a Henschel mixer and blended for 5 minutes. Next, this blend was kneaded with a kneader mixer at a kneading temperature of 100 ° C. for 20 minutes, and further kneaded at a kneading temperature of 120 ° C. for 20 minutes. The obtained kneaded product was cooled and then kneaded with a heated three roll, cooled and coarsely crushed to obtain a colored resin A containing a pigment at a concentration of 30% by weight.

(2) Production of colored resin particle dispersion (A) (step (2))
In a flask equipped with a stirrer, 285 g of polyester resin (A), 210 g of polyester resin (B), 150 g of colored resin A, polyoxyethylene alkyl ether (nonionic surfactant, trade name: Emulgen 430, Kao Corporation) 6 g, 15 wt% sodium dodecylbenzenesulfonate aqueous solution (trade name: Neoperex G-15, anionic surfactant) manufactured by Kao Corporation, 40 g, pH 8 phosphorus obtained in Production Example 4 as an aqueous liquid 109.7 g of an aqueous solution containing a potassium salt of acid (10% by weight in terms of potassium hydroxide) and 189.7 g of deionized water were added, and the mixture was heated to 95 ° C. with melting and melted, and at 95 ° C. for 2 hours. By mixing, a resin mixture was obtained.
Next, 1182.5 g of deionized water was added dropwise at a rate of 6 g / min while stirring to obtain an emulsion. Next, the obtained emulsion was cooled to 25 ° C., and a colored resin particle dispersion (A) was obtained through a 200 mesh (mesh 105 μm) wire mesh. Table 1 shows the solid content concentration of the obtained dispersion and the volume median particle size of the colored resin particles in the dispersion.

(3) Production of fused particles (A) (step (3))
(3-1) Production of Aggregated Particle Dispersion (1) (Step (3-1))
In a four-necked flask with an internal volume of 10 liters equipped with a dehydrating tube, a stirrer, and a thermocouple, 220 g of colored resin particle dispersion (A) (66.4 g in terms of solid content), 43.8 g of deionized water, and release 34.9 g of the mold agent particle dispersion was added and mixed at 25 degrees. Next, while stirring the mixture, an aqueous solution in which 17.4 g of ammonium sulfate was dissolved in 181 g of deionized water was added dropwise at 25 ° C. over 10 minutes, and then the temperature was raised to 50 ° C. over 2 hours. The mixture was kept at 50 ° C. until the median particle size became 4.2 μm to obtain an aggregated particle dispersion (1). The aggregating agent concentration in the aggregated particle dispersion was 0.65 mol / L.
(3-2) Production of Aggregated Particle Dispersion Liquid (2) (Step (3-2))
The aggregated particle dispersion (1) obtained in (3-1) was kept at 50 ° C., and 26.3 g of the resin particle dispersion (B) was added dropwise at a rate of 0.4 g / min. After completion of the dropwise addition, while raising the temperature to 56 ° C. over 6 hours, 105.2 g of the resin particle dispersion (B) was further dropped at a rate of 0.4 g / min, and the volume median particle size was 5.1 μm. A particle dispersion (2) was obtained. The resulting aggregated particle dispersion (2) had a coagulant concentration of 0.52 mol / L. Furthermore, an aqueous solution in which 16.7 g of sodium alkyl ether sulfate (trade name: EMAL E27C, solid content: 28% by weight) dissolved in 1321 g of deionized water was added to the aggregated particle dispersion (2). , Mixed.
(3-3) Preparation of fused particle dispersion (step (3-3))
The dispersion obtained in step (3-2) was heated to 70 ° C. over 2 hours and then held at 70 ° C. for 3 hours to obtain fused particles having a circularity of 0.960. Then, it cooled to 25 degreeC. The concentration of the flocculant in the system was 0.14 mol / L.

(4) Post-processing step The fused particle dispersion obtained in step (3-3) was suction filtered, washed with deionized water, and dried at 33 ° C. to obtain toner particles. 100 parts by weight of the toner particles, 2.5 parts by weight of hydrophobic silica (trade name: RY50, manufactured by Nippon Aerosil Co., Ltd., average particle size: 0.04 μm), and hydrophobic silica (trade name: Cabo Seal TS720, Cabot Corporation) Manufactured, average particle size: 0.012 μm) was put in a Henschel mixer, stirred, and passed through a 150-mesh sieve to obtain magenta toner (A). The volume-median particle size of the obtained magenta toner (A) was 4.9 μm, and the number percentage of 2 μm or less was 4.2%. Table 1 shows the physical properties and evaluation results of magenta toner (A).

Example 2
(Manufacture of magenta toner (B))
In the production of the colored resin particle dispersion (A) of Example 1 (2), an aqueous solution containing a potassium salt of phosphoric acid at pH 8 was used as an aqueous solution containing a potassium salt of phosphoric acid at pH 10 obtained in Production Example 4. A magenta toner (B) was obtained in the same manner as in Example 1 except for changing to.

Comparative Example 1
(Manufacture of magenta toner (C))
In the production of the colored resin particle dispersion (A) of Example 1 (2), an aqueous solution containing potassium phosphate having a pH of 8 was added to 139 g of an aqueous potassium hydroxide solution (concentration: 10% by weight, pH 14) described in Table 1. Magenta toner C was obtained in the same manner as in Example 1 except that the amount of deionized water was changed to 109 g and the amount of deionized water to be dropped was changed to 1145 g.

Comparative Example 2
(Manufacture of magenta toner (D))
In the same manner as in Example 1, except that (1) colored resin A in Example 1 was not produced, and (2) production of colored resin particle dispersion (A) was changed to the following (2 ′), Magenta toner (D) was obtained.
(2 ′) Production of colored resin particle dispersion (D) (step (2))
In a flask equipped with a stirrer, 390 g of polyester resin (A), 210 g of polyester resin (B), polyoxyethylene alkyl ether (nonionic surfactant, trade name: Emulgen 430, manufactured by Kao Corporation) 6 g, 15 40 g of a weight% sodium dodecylbenzenesulfonate aqueous solution (anionic surfactant, trade name: Neoperex G-15, manufactured by Kao Corporation), a potassium salt of phosphoric acid at pH 8 obtained in Production Example 4 as an aqueous liquid 111.4 g of aqueous solution containing potassium hydroxide) and 89.9 g of deionized water were added, heated to 95 ° C. with stirring and melted, mixed at 95 ° C. for 2 hours, and resin mixture Got. Subsequently, stirring was stopped, and 143.3 g of a paste-like pigment (Pigment Red 48: 3, manufactured by Dainichi Seika Kogyo Co., Ltd., solid content concentration 31.4% by weight) was added, followed by stirring at 200 r / min. Then, the mixture was heated to 100 ° C. in 20 minutes, and further mixed at 100 ° C. for 30 minutes. Thereafter, the contents were stabilized at 95 ° C., and then 1182.5 g of deionized water was added dropwise at a rate of 6 g / min while stirring to obtain an emulsion. Next, the obtained emulsion was cooled to 25 ° C., and a colored resin particle dispersion (D) was obtained through a 200-mesh (mesh opening 105 μm) wire mesh. Table 1 shows the solid content concentration of the obtained dispersion and the volume median particle size of the colored resin particles in the dispersion.

Comparative Example 3
(Manufacture of magenta toner (E))
In Example 1 (1) Production of colored resin A was changed to the following (1 ′) to produce colored resin B. (2) In production of colored resin particle dispersion (A), colored resin A was A magenta toner (E) was obtained in the same manner as in Example 1 except that the colored resin B obtained in (1 ′) was changed.
(1 ′) Production of colored resin B (step (1))
70 parts by weight of fine powder of the polyester resin (C) of Production Example 3 and 99.3 parts by weight of a paste-like magenta pigment (Pigment Red 122, manufactured by DIC Corporation, solid content concentration: 30.2% by weight) 30 parts by weight) was charged into a Henschel mixer and blended for 5 minutes. Next, this blend was kneaded with a kneader mixer at a kneading temperature of 100 ° C. for 20 minutes, and further kneaded at a kneading temperature of 120 ° C. for 20 minutes. The obtained kneaded product was cooled and then kneaded with a heated three roll, cooled and crushed to obtain a colored resin B containing a pigment at a concentration of 30% by weight.

Comparative Example 4
(Manufacture of magenta toner (F))
In the same manner as in Example 1, except that the aqueous solution containing potassium phosphate at pH 8 of Comparative Example 3 was changed to 137.2 g of 10 wt% aqueous potassium hydroxide (pH 14) and deionized water to 165.1 g, magenta Toner (F) was obtained.

  From Table 1, it can be seen that the electrophotographic magenta toner obtained by the method for producing an electrophotographic toner of the present invention is superior in fixing property and image density as compared with the toner of the comparative example, and can achieve both of them. .

Claims (12)

A method for producing an electrophotographic magenta toner comprising the following steps (1) to (3):
Step (1): Step of obtaining a colored resin by melt-mixing the polyester resin (a) and a pigment represented by the following formula

(In the formula, M represents barium, calcium, strontium or manganese.)
Step (2): Step of obtaining colored resin particles (A) by melting and mixing the colored resin and the polyester resin (b) in the presence of an aqueous liquid having a pH of 7 to 11 to obtain colored resin particles (A) Step (3): Colored resin Aggregating and fusing particles (A)   The method for producing a magenta toner for electrophotography according to claim 1, wherein the melt mixing in the step (2) is performed in the presence of a salt of a polybasic acid.   The method for producing a magenta toner for electrophotography according to claim 1 or 2, wherein the mixing temperature in the step (1) is not less than the softening point of the polyester resin (a).   The method for producing a magenta toner for electrophotography according to claim 2 or 3, wherein the salt of the polybasic acid is a salt of an inorganic acid containing a phosphorus atom.   The method for producing a magenta toner for electrophotography according to any one of claims 1 to 4, wherein the emulsification method in step (2) is phase inversion emulsification. The method for producing an electrophotographic magenta toner according to any one of claims 1 to 5, comprising the following steps (3-1) to (3-3) in step (3).
Step (3-1): Step of obtaining the aggregated particle dispersion (1) by mixing the colored resin particles (A), the release agent particles, and the flocculant in an aqueous medium Step (3-2): Aggregated particles Step of obtaining aggregated particle dispersion (2) by adding resin particles (C) containing polyester resin (c) to dispersion (1) Step (3-3): Aggregated particle dispersion (2) Fusion process   The temperature at the time of fusing in the step (3-3) is not higher than the melting point of the release agent contained in the release agent particles, and is a temperature not lower than 5 ° C. lower than the glass transition point of the polyester resin (c). The method for producing a magenta toner for electrophotography according to claim 6.   In step (3-2), after adding resin particles (C) to the aggregated particle dispersion (1), an anionic surfactant is added to obtain an aggregated particle dispersion (2). The method for producing a magenta toner for electrophotography according to 6 or 7.   The method for producing a magenta toner for electrophotography according to any one of claims 6 to 8, wherein the flocculant has a cation valence of 1.   The method for producing a magenta toner for electrophotography according to any one of claims 6 to 9, wherein the flocculant is an inorganic ammonium salt.   The temperature for fusing in the step (3-3) is equal to or higher than the glass transition point of the resin particles (C) containing the polyester resin (c), for electrophotography according to any one of claims 6 to 10. A method for producing magenta toner.   The magenta toner for electrophotography obtained by the manufacturing method in any one of Claims 1-11.