JP2015045719A - Toner for electrostatic charge image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development that provides excellent low-temperature fixability and a sufficient heat-resistant storage property, and has environmental stability in a charged state.SOLUTION: In a toner for electrostatic charge image development consisting of toner particles having a core-shell structure in which the surface of each of core particles is coated with a shell layer, the core particle contains a vinyl resin; the shell layer contains an amorphous polyester resin and crystalline polyester resin; and the crystalline polyester resin is dispersed as a domain phase in a matrix phase composed of the amorphous polyester resin.

Description

  The present invention relates to an electrostatic charge image developing toner used for electrophotographic image formation.

In recent years, in the field of electrostatic charge image developing toner (hereinafter, also simply referred to as “toner”) used for electrophotographic image formation, development of toner that meets various demands from the market has been made. .
For example, as a toner corresponding to high image quality, a toner having a sharp particle size distribution is required because the reproducibility of minute dots is remarkably improved by aligning development behavior of individual toner particles.

  However, it is not easy to obtain a toner having a sharp particle size distribution by the conventional pulverization method. On the other hand, an emulsion polymerization aggregation method has been proposed as a production method capable of arbitrarily controlling the shape and particle size distribution of toner particles. In this production method, a dispersion of a fine particle of a colorant and, if necessary, a dispersion of another toner component are mixed with an emulsified dispersion of fine particles of a binder resin, and the agglomeration agent is added or the pH is adjusted while stirring. In this method, toner particles are obtained by agglomerating these fine particles by control and further fusing them by heating.

From the viewpoint of energy saving, development of a toner that can be fixed with less energy is in progress.
In order to obtain a toner that can be fixed at a low temperature, it is necessary to use a binder resin having a low melting temperature and low melt viscosity.
However, if a binder resin having a small glass transition point or molecular weight is used to lower the melting temperature or melt viscosity, a new problem arises in that the heat-resistant storage property of the toner is lowered.

  In order to achieve both low-temperature fixability and heat-resistant storage stability of a toner, a technique that employs a toner having a core-shell structure has been proposed (see, for example, Patent Document 1). In other words, by forming a shell layer made of a resin with a high softening point and excellent heat resistance on the surface of core particles made of a resin that exhibits low-temperature fixing performance, both low-temperature fixability and heat-resistant storage stability are achieved. Can do. In particular, the production method using the emulsion polymerization aggregation method has an advantage that such shape control can be easily performed.

  However, in recent years, as the speed of copying machines and printers and the diversification of paper types have progressed in the field of production printing, even the toner with the core-shell structure as described above has low-temperature fixability and heat-resistant storage stability. It has become difficult to achieve a good balance.

In order to solve such a problem, a toner using a polyester resin as a resin material for the shell layer has been proposed (for example, see Patent Document 2). This polyester resin has the advantage that it can be easily designed with a low softening point while maintaining a high glass transition point compared to a vinyl resin. By using a polyester resin for the shell layer, excellent low-temperature fixing is possible. And heat storage stability can be obtained.
However, the current situation is that the speed of copying machines and printers has not yet been improved, and in particular, fixing properties for paper types with large irregularities such as embossed paper have not been sufficiently obtained.

Patent Documents 3 to 5 propose toners containing a crystalline polyester resin that is highly responsive to heat.
However, since the toner described in Patent Document 3 uses an amorphous polyester resin for the shell layer, there is a problem that sufficient thermal responsiveness cannot be obtained and excellent low-temperature fixability cannot be obtained. Further, in the toners described in Patent Document 4 and Patent Document 5, a crystalline polyester resin is used for the shell layer, and sufficient thermal responsiveness can be obtained and excellent low-temperature fixability can be obtained. However, it is compatible with other resins in the shell layer, and there is a problem that sufficient heat-resistant storage property cannot be obtained. Further, the toner described in Patent Document 5 has a problem that the content ratio of the crystalline polyester resin in the toner is high, the toner has high hygroscopicity, and the charged state of the toner is affected by the environmental atmosphere.

JP 2005-221933 A JP 2012-230371 A JP 2012-255957 A JP 2011-149986 A JP 2012-128404 A

  The present invention has been made in view of the circumstances as described above, and the object thereof is to obtain sufficient heat-resistant storage stability while obtaining excellent low-temperature fixability, and also in a charged state environment. An object of the present invention is to provide a toner for developing an electrostatic image having stability.

The electrostatic image developing toner of the present invention is an electrostatic image developing toner comprising toner particles having a core-shell structure in which a shell layer is coated on the surface of a core particle.
The core particle contains a vinyl resin,
The shell layer contains an amorphous polyester resin and a crystalline polyester resin, and the crystalline polyester resin is dispersed as a domain phase in a matrix phase of the amorphous polyester resin. And

  In the electrostatic image developing toner of the present invention, the average diameter of the domain phase is preferably 0.15 to 1 μm.

  In the electrostatic image developing toner of the present invention, the crystalline polyester resin preferably has an ester group concentration of 0.1 to 7.5 mmol / g.

  In the electrostatic image developing toner of the present invention, the amorphous polyester resin is preferably a vinyl-modified one.

  In the electrostatic image developing toner of the present invention, the content of the crystalline polyester resin in the toner particles is preferably 5 to 30% by mass.

  According to the toner for developing an electrostatic charge image of the present invention, the toner particle is a shell layer in which the domain phase of the crystalline polyester resin is dispersed in the surface of the core particle of the vinyl resin in the matrix phase of the amorphous polyester resin. By being coated, sufficient heat-resistant storage stability can be obtained while excellent low-temperature fixability can be obtained, and environmental stability in a charged state can be obtained. In particular, high fixability can be obtained even for high-speed copying machines and printers and for paper types with large irregularities such as embossed paper.

FIG. 3 is a cross-sectional view for explaining an example in the configuration of toner particles according to the present invention.

  Hereinafter, the present invention will be described in detail.

〔toner〕
The toner of the present invention comprises toner particles containing at least a binder resin, and the toner particles contain an internal additive such as a colorant, magnetic powder, a release agent, and a charge control agent as desired. It can be. Further, external additives such as a fluidizing agent and a cleaning aid may be added to the toner particles.

  The toner particles according to the toner of the present invention have a core-shell structure in which a shell layer is coated on the core particle surface, and the shell layer has a domain-matrix structure in which a domain phase is dispersed in a matrix phase. Have.

Specifically, as shown in FIG. 1, the toner particles 10 are formed by coating the surface of core particles 11 containing a vinyl resin with a shell layer 12, and the shell layer 12 is a matrix phase made of an amorphous polyester resin. 12a has a structure in which a domain phase 12b of a crystalline polyester resin is dispersed.
The toner particles 10 are not limited to those in which the shell layer 12 completely covers the surface of the core particle 11. For example, the shell layer 12 does not completely cover the surface of the core particle 11, and a part of the surface of the core particle 11 is formed. It may be exposed.

  Here, the domain-matrix structure refers to a structure in which a domain phase having a closed interface (boundary between phases) exists in a continuous matrix phase.

  The structure as described above can be observed by measuring a section of toner particles stained with ruthenium oxide (VIII) or osmium oxide (VIII) by a transmission electron microscope (TEM) by a conventional method. In the case of cutting a section with an ultramicrotome, the thickness of the section is set to 100 nm.

In the toner particle 10, the average diameter of the domain phase 12b of the crystalline polyester resin is preferably 150 to 1000 nm, and more preferably 150 to 500 nm.
The average diameter of the domain phase is a value measured by an observation image of a transmission electron microscope (TEM). Specifically, in the observation image of TEM, the diameter of each domain phase is the average value of the horizontal ferret diameter and the vertical ferret diameter, and the measurement is performed for the domain phase diameter of 100 nm or more. Is calculated as the average diameter of the domain phase.

  In the toner of the present invention, excellent low-temperature fixability can be obtained because the shell layer contains a crystalline polyester resin with high thermal responsiveness. Particularly, the speed of copying machines and printers, embossed paper, etc. High fixability can be obtained even for paper types with large irregularities. In addition, the crystalline polyester resin is in a domain phase in the matrix phase, that is, the crystalline polyester resin is contained in the amorphous polyester resin in an incompatible state, thereby ensuring sufficient heat-resistant storage stability. can do. Further, since the core particles are made of a vinyl resin, the vinyl resin has a lower polarity than the polyester resin, so that the hygroscopic property of the whole toner is reduced and the environmental stability of the charged state can be obtained. .

[Binder resin]
The binder resin constituting the toner particles according to the present invention is composed of a vinyl resin contained in the core particles, and an amorphous polyester resin and a crystalline polyester resin contained in the shell layer. It may be contained.

(Vinyl resin)
The vinyl resin constituting the core particle is an amorphous resin formed using a monomer having a vinyl group (hereinafter also referred to as “vinyl monomer”).
Specific examples of the vinyl resin include a styrene resin, an acrylic resin, and a styrene acrylic copolymer resin.

The following can be used as the vinyl monomer. As a vinyl monomer, it can be used individually by 1 type or in combination of 2 or more types.
(1) Styrene monomer Styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert -Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, and derivatives thereof.
(2) (meth) acrylic acid ester monomer (meth) methyl acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate, T-butyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, phenyl (meth) acrylate, (meth ) Diethylaminoethyl acrylate, dimethylaminoethyl (meth) acrylate, and derivatives thereof.
(3) Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate and the like.
(4) Vinyl ethers Vinyl methyl ether, vinyl ethyl ether and the like.
(5) Vinyl ketones Vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone and the like.
(6) N-vinyl compounds N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone and the like.
(7) Others Vinyl compounds such as vinyl naphthalene and vinyl pyridine, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide.

Moreover, as a vinyl monomer, it is preferable to use the monomer which has ionic dissociation groups, such as a carboxy group, a sulfonic acid group, and a phosphoric acid group, for example. Specifically, there are the following.
Examples of the monomer having a carboxy group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, and the like. Examples of the monomer having a sulfonic acid group include styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, and the like. Furthermore, examples of the monomer having a phosphate group include acid phosphooxyethyl methacrylate.
In the present invention, when a monomer having an ionic dissociation group is used as the vinyl monomer, the proportion of the monomer having an ionic dissociation group in all vinyl monomers is 2 to 15% by mass. It is preferable that If the proportion of the monomer having an ionic dissociation group is excessive, the amount of moisture adsorbed on the surface of the toner particles may increase, which may cause generation of toner blisters or expansion of the difference in charge amount environment.

  Furthermore, polyfunctional vinyls can be used as the vinyl monomer, and the vinyl resin can have a crosslinked structure. Polyfunctional vinyls include divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol Examples include diacrylate.

It is preferable that the glass transition point (Tg) of a vinyl resin is 30-70 degreeC, More preferably, it is 40-60 degreeC.
When the glass transition point of the vinyl resin is in the above range, sufficient low-temperature fixing property and heat-resistant storage property can be reliably achieved.
When the glass transition point of the vinyl resin is too low, the heat resistance (thermal strength) of the toner is lowered, and there is a possibility that sufficient heat resistant storage stability cannot be obtained. On the other hand, if the glass transition point of the vinyl resin is excessive, sufficient low-temperature fixability may not be obtained.

The glass transition point (Tg) of the vinyl resin is a value measured using “Diamond DSC” (manufactured by Perkin Elmer).
As a measurement procedure, 3.0 mg of a measurement sample (vinyl resin) is sealed in an aluminum pan and set in a holder. The reference used an empty aluminum pan. The measurement conditions were a measurement temperature of 0 ° C. to 200 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 10 ° C./min, and heat-cool-heat temperature control. Perform analysis based on the data in Heat, draw a baseline extension before the rise of the first endothermic peak, and a tangent line indicating the maximum slope between the rise of the first peak and the peak apex, Let the intersection be the glass transition point.

  The softening point (Tsp) of the vinyl resin is preferably 90 to 130 ° C, more preferably 100 to 120 ° C.

In the present invention, the softening point (Tsp) of the vinyl resin is a value measured as follows.
First, in an environment of 20 ° C. ± 1 ° C. and 50% ± 5% RH, 1.1 g of a measurement sample (vinyl resin) is placed in a petri dish and left flat for 12 hours or more. ”(Manufactured by Shimadzu Corporation) with a force of 3820 kg / cm 2 for 30 seconds to create a cylindrical molded sample having a diameter of 1 cm, and this molded sample was then heated at 24 ° C. ± 5 ° C. and 50% ± 20% RH. Under the environment, the hole of the cylindrical die was measured with a flow tester “CFT-500D” (manufactured by Shimadzu Corporation) under the conditions of a load of 196 N (20 kgf), a start temperature of 60 ° C., a preheating time of 300 seconds, and a temperature increase rate of 6 ° C. (1 mm diameter x 1 mm) offset method temperature Tof that was extruded from the end of preheating using a 1 cm diameter piston and measured at a melt temperature measurement method of temperature rising method with an offset value of 5 mm Let fset be the softening point.

The molecular weight of the vinyl resin measured by gel permeation chromatography (GPC) is 10,000 to 80,000 in terms of weight average molecular weight (Mw), and more preferably 20,000 to 60,000.
When the weight average molecular weight of the vinyl resin is in the above range, sufficient low-temperature fixability and hot offset resistance can be reliably achieved.
When the weight average molecular weight of the vinyl resin is excessive, there is a possibility that sufficient low-temperature fixability cannot be obtained. On the other hand, when the weight average molecular weight of the vinyl resin is too small, hot offset resistance may not be obtained.

The molecular weight of the vinyl resin by gel permeation chromatography (GPC) is a value measured as follows.
Specifically, using an apparatus “HLC-8120GPC” (manufactured by Tosoh Corporation) and a column “TSKguardcolumn + TSKgelSuperHZ-M3 series” (manufactured by Tosoh Corporation), while maintaining the column temperature at 40 ° C., tetrahydrofuran (THF) was used as a carrier solvent. The sample was flowed at a flow rate of 0.2 ml / min, and the measurement sample (vinyl resin) was dissolved in tetrahydrofuran to a concentration of 1 mg / ml under a dissolution condition in which treatment was performed for 5 minutes using an ultrasonic disperser at room temperature. A sample solution is obtained by processing with a 2 μm membrane filter, and 10 μL of this sample solution is injected into the apparatus together with the above carrier solvent, detected using a refractive index detector (RI detector), and the molecular weight of the measurement sample A calibration curve was measured using monodisperse polystyrene standard particles. Is used to calculate. Ten polystyrenes were used for calibration curve measurement.

The content ratio of the vinyl resin is preferably 20 to 90% by mass in the toner particles.
When the content ratio of the vinyl resin is within the above range, excellent low-temperature fixability and environmental stability of the charged state can be reliably obtained.

(Amorphous polyester resin)
The amorphous polyester resin constituting the shell layer is a known polyester resin obtained by a polycondensation reaction between a divalent or higher carboxylic acid (polyvalent carboxylic acid) and a divalent or higher alcohol (polyhydric alcohol). In the differential scanning calorimetry (DSC), it refers to a resin that does not show a clear endothermic peak. The clear endothermic peak specifically means a peak in which the half-value width of the endothermic peak is within 15 ° C. when measured at a rate of temperature increase of 10 ° C./min in differential scanning calorimetry (DSC). To do.

  Examples of the polyvalent carboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. Acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid Aliphatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, etc .; maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, isododecenyl succinic acid, n- Aliphatic unsaturated dicals such as dodecenyl succinic acid and n-octenyl succinic acid Phosphate; trimellitic acid, pyromellitic acid, naphthalene tricarboxylic acid, naphthalene tetracarboxylic acid, pyrene-tricarboxylic acid, and the like divalent or higher carboxylic acids, such as pyrene-tetracarboxylic acid.

  Examples of the polyhydric alcohol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8- Octanediol, 1,9-nonanediol, 1,10-dodecanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18- Aliphatic diols such as octadecanediol and 1,20-eicosanediol; Bisphenols such as bisphenol A and bisphenol F; and alkylene oxide adducts of bisphenols such as ethylene oxide adducts and propylene oxide adducts; glycerin, Pentaerythrito , Mention may be made of hexamethylol melamine, hexa ethylene melamine, tetramethylol benzoguanamine, etc. trihydric or higher polyols, such as tetra-ethyl benzoguanamine the.

  Part or all of the amorphous polyester resin contained in the shell layer has a high affinity with the vinyl resin of the core particles and can form a shell layer with a uniform film thickness. It is preferable that

  The vinyl-modified amorphous polyester resin (hereinafter also referred to as “vinyl-modified polyester resin”) refers to a composite resin in which an amorphous polyester polymer segment and a vinyl polymer segment are chemically bonded.

  The vinyl polymerization segment is formed of a vinyl monomer, and examples of the vinyl monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decyl Styrene monomers such as styrene, pn-dodecylstyrene, 2,4-dimethylstyrene, 3,4-dichlorostyrene, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylic Cyclohexyl acid, phenyl acrylate, methyl methacrylate, ethyl methacrylate, (Meth) acrylic acid such as butyl tacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate In addition to these, those exemplified as the vinyl monomer for forming the vinyl resin of the core particle can be used. Moreover, said vinyl monomer can be used individually by 1 type or in combination of 2 or more types.

It is preferable that the content rate of the vinyl polymerization segment in a vinyl modified polyester resin is 5-30 mass%, More preferably, it is 15-25 mass%.
Specifically, the content ratio of the vinyl polymerization segment is the total mass of the resin material used for synthesizing the vinyl-modified polyester resin, that is, the polyvalent carboxylic acid and the polyhydric alcohol serving as the amorphous polyester polymerization segment, It is the ratio of the mass of the vinyl monomer to the total mass of the total of the vinyl monomer to be the vinyl polymerization segment and the both reactive monomers for bonding them.
When the content ratio of the vinyl polymerization segment is within the above range, sufficient adhesion between the core particles and the shell layer is obtained, and the heat-resistant storage property is further improved.

An existing general scheme can be used as a method for synthesizing the vinyl-modified polyester resin as described above. The following three methods are listed as typical methods.
(1) After performing an addition polymerization reaction of a vinyl monomer to form a vinyl polymerization segment, a polycondensation reaction of a polyvalent carboxylic acid and a polyhydric alcohol to form an amorphous polyester polymerization segment is performed, A method of adding a trivalent or higher valent vinyl monomer as a cross-linking agent to the reaction system as necessary to further advance the condensation polymerization reaction.
(2) After performing a polycondensation reaction of a polyvalent carboxylic acid and a polyhydric alcohol to form an amorphous polyester polymerization segment, an addition polymerization reaction of a vinyl monomer to form a vinyl polymerization segment is performed, Thereafter, a tri- or higher valent vinyl monomer serving as a cross-linking agent is added to the reaction system as necessary, and the polycondensation reaction further proceeds under temperature conditions suitable for the polycondensation reaction.
(3) Addition polymerization reaction of a vinyl monomer for forming a vinyl polymerization segment under a temperature condition suitable for the addition polymerization reaction, and a polyvalent carboxylic acid and a polyvalent acid for forming an amorphous polyester polymerization segment. A polyhydric alcohol polycondensation reaction is carried out in parallel, and after the addition polymerization reaction is completed, a trivalent or higher vinyl monomer as a cross-linking agent is added to the reaction system as necessary, and a temperature suitable for the polycondensation reaction A method in which the condensation polymerization reaction further proceeds under conditions.

  Since the vinyl-modified polyester resin has a non-crystalline polyester polymer segment and a vinyl polymer segment bonded via an amphoteric monomer, a specific production method includes, for example, the treatment of an amphoteric monomer with a polyvalent carboxyl. When used with acid / polyhydric alcohol and / or vinyl monomer, polycarboxylic acid / polyhydric alcohol is present at least before, during and after the step of addition polymerization of vinyl monomer. To conduct the condensation polymerization reaction.

Both reactive monomers have at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an epoxy group, a primary amino group and a secondary amino group in the molecule, preferably a hydroxyl group and / or carboxyl. It is preferably a compound having a group, more preferably a carboxyl group and an ethylenically unsaturated bond, that is, a vinyl carboxylic acid. Specific examples of the both reactive monomers include, for example, acrylic acid, methacrylic acid, fumaric acid, maleic acid and the like, and these hydroxyalkyl (1 to 3 carbon atoms) esters may be used. In view of the above, acrylic acid, methacrylic acid, and fumaric acid are preferable.
In addition, it is preferable from the viewpoint of durability that a monovalent vinyl carboxylic acid is used as the bireactive monomer rather than a polyvalent vinyl carboxylic acid. This is presumably because monovalent vinyl-based carboxylic acids are highly reactive with vinyl monomers and are therefore easily hybridized. On the other hand, when a dicarboxylic acid such as fumaric acid is used as the bireactive monomer, the durability is slightly inferior. This is presumably because the dicarboxylic acid has a low reactivity with the vinyl monomer and is difficult to uniformly hybridize, so that it takes a domain structure.

  From the viewpoint of improving the low-temperature fixability of the toner, the amount of both reactive monomers used is preferably 1 to 10 parts by weight, more preferably 4 to 8 parts by weight, based on 100 parts by weight of the total amount of vinyl monomers. 0.3-8 mass parts is preferable with respect to 100 mass parts of total amounts of polyhydric carboxylic acid and polyhydric alcohol, and 0.5-5 mass parts is more preferable.

  The addition polymerization reaction can be performed by a conventional method in the presence of a radical polymerization initiator, a crosslinking agent, or the like, in an organic solvent or in the absence of a solvent, but the temperature condition is preferably 110 to 200 ° C. ° C is more preferred. Examples of the radical polymerization initiator include dialkyl peroxide, dibutyl peroxide, butyl peroxy-2-ethylhexyl monocarboxylic acid and the like, and these can be used alone or in combination of two or more.

  The condensation polymerization reaction can be performed, for example, in an inert gas atmosphere at a temperature of 180 to 250 ° C., but is preferably performed in the presence of an esterification catalyst, a polymerization inhibitor, or the like. Examples of the esterification catalyst include tin (II) compounds having no Sn-C bond such as dibutyltin oxide, titanium compound, tin octylate, etc., and these may be used alone or in combination. it can.

  The glass transition point (Tg) of the amorphous polyester resin is preferably 40 to 80 ° C, more preferably 50 to 70 ° C.

  The molecular weight measured by gel permeation chromatography (GPC) of the amorphous polyester resin is 10,000 to 100,000 in terms of weight average molecular weight (Mw) and 2,000 to 5,000 in terms of number average molecular weight (Mn). It is preferable that

  The softening point (Tsp) of the amorphous polyester resin is preferably 90 to 130 ° C, more preferably 100 to 120 ° C.

  The glass transition point of the amorphous polyester resin, the molecular weight and softening point measured by gel permeation chromatography (GPC) were measured in the same manner as above except that the amorphous polyester resin was used as the measurement sample. Value.

The amorphous polyester resin is preferably contained at a ratio of 5 to 75% by mass in the toner particles.
When the content ratio of the amorphous polyester resin is in the above range, both low-temperature fixability and heat-resistant storage stability can be achieved, and environmental stability of the charged state can be obtained.

(Crystalline polyester resin)
The crystalline polyester resin constituting the shell layer is a known polyester resin obtained by a polycondensation reaction of a divalent or higher carboxylic acid (polyvalent carboxylic acid) and a divalent or higher alcohol (polyhydric alcohol). In differential scanning calorimetry (DSC), it refers to a resin having a clear endothermic peak rather than a stepwise endothermic change. The clear endothermic peak specifically means a peak in which the half-value width of the endothermic peak is within 15 ° C. when measured at a rate of temperature increase of 10 ° C./min in differential scanning calorimetry (DSC). To do.

The polyvalent carboxylic acid is a compound containing two or more carboxy groups in one molecule.
Specifically, for example, saturated aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid and n-dodecyl succinic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; phthalates Aromatic dicarboxylic acids such as acid, isophthalic acid and terephthalic acid; trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid; and anhydrides of these carboxylic acid compounds or alkyl esters having 1 to 3 carbon atoms Etc.
These may be used individually by 1 type and may be used in combination of 2 or more type.

A polyhydric alcohol is a compound containing two or more hydroxyl groups in one molecule.
Specifically, for example, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol Aliphatic diols such as 1,8-octanediol, neopentyl glycol and 1,4-butenediol; trihydric or higher polyhydric alcohols such as glycerin, pentaerythritol, trimethylolpropane and sorbitol.
These may be used individually by 1 type and may be used in combination of 2 or more type.

The ester group concentration of the crystalline polyester resin is preferably 0.1 to 7.5 mmol / g, more preferably 3.0 to 7.5 mmol / g.
When the ester group concentration of the crystalline polyester resin is within the above range, the crystalline polyester resin has low compatibility with the amorphous polyester resin. Therefore, the crystalline polyester resin is dispersed as a domain phase in the matrix phase of the amorphous polyester resin, and the crystalline polyester resin advances the plasticization of the amorphous polyester resin before heat fixing. Since there is no, heat-resistant storage property can be ensured.
When the ester group concentration of the crystalline polyester resin is excessive, the crystalline polyester resin is highly compatible with the amorphous polyester resin, the domain phase is not formed by the crystalline polyester resin, and sufficient heat-resistant storage stability is ensured. You may not be able to. On the other hand, when the ester group concentration of the crystalline polyester resin is too low, the crystalline polyester resin becomes completely incompatible with the amorphous polyester resin, and the crystalline polyester resin becomes an amorphous polyester resin even during heat fixing. On the other hand, the low-temperature fixability deteriorates without causing plasticization.

Here, the ester group concentration is the ratio of ester groups (ester bonds) in the crystalline polyester resin, and indicates the degree of affinity for water. The larger the value, the higher the affinity for water. is there.
In the present invention, the ester group concentration is a value calculated by the following formula (1).
Formula (1): Ester group concentration = [Average number of moles of moieties capable of forming ester groups contained in polyvalent carboxylic acid and polyhydric alcohol forming crystalline polyester resin / ((of polyvalent carboxylic acid and polyhydric alcohol Total molecular weight)-(molecular weight of water separated by dehydration polycondensation × number of moles of ester group))] × 1000
The ester group concentration of the crystalline polyester resin can be controlled by the monomer species.

An example of calculating the ester group concentration of the crystalline polyester resin is shown below.
The crystalline polyester resin obtained by the polyvalent carboxylic acid represented by the following formula (a) and the polyhydric alcohol represented by the following formula (b) is represented by the following formula (c).
Formula ^{(a): HOOC-R 1} -COOH
Formula (b): HO—R ² —OH
Formula (c): - (- OCO -R 1 -COO-R 2 -) n -
“Average number of moles of the portion that can be an ester group contained in the polyvalent carboxylic acid and polyhydric alcohol forming the crystalline polyester resin” means the number of moles of the carboxy group of the polyvalent carboxylic acid forming the crystalline polyester resin. And the average number of moles of hydroxyl group of the polyhydric alcohol, specifically, the number of moles of carboxy group of the polycarboxylic acid of the formula (a) “2” and the hydroxyl number of the polyhydric alcohol of the formula (b) The average is “2” with the number of moles of the group “2”.
When the molecular weight of the polyvalent carboxylic acid of the formula (a) is m1, the molecular weight of the polyhydric alcohol of the formula (b) is m2, and the molecular weight of the crystalline polyester resin of the formula (c) is m3, “(polyvalent carboxylic acid) (Molecular weight of acid and polyhydric alcohol)-(molecular weight of water separated by dehydration polycondensation × number of moles of ester group) ”is (m1 + m2) − (18 × average number of moles of ester group“ 2 ”) Therefore, the molecular weight “m3” of the crystalline polyester resin of the formula (c) is obtained.
From the above, the ester group concentration of the crystalline polyester resin represented by the formula (c) is “2 / m 3”.
In addition, when two or more polycarboxylic acids or two or more polyhydric alcohols are used in combination, the average of the carboxy group and molecular weight of each polycarboxylic acid and the average of the hydroxyl group and molecular weight of the polyhydric alcohol Become.

The melting point (Tm) of the crystalline polyester resin is preferably 40 to 95 ° C, more preferably 55 to 80 ° C.
When the melting point of the crystalline polyester resin is in the above range, sufficient low-temperature fixability can be obtained.
When the melting point of the crystalline polyester resin is excessively low, the obtained toner has a low thermal strength, and there is a possibility that sufficient heat storage stability and hot offset resistance cannot be obtained. Moreover, when the melting point of the crystalline polyester resin is excessively high, there is a possibility that sufficient low-temperature fixability cannot be obtained.
The melting point of the crystalline polyester resin can be controlled by the resin composition.

The melting point of the crystalline polyester resin is a value measured as follows.
The melting point of the crystalline polyester indicates the temperature at the peak top of the endothermic peak, and is measured by DSC by differential scanning calorimetry using “Diamond DSC” (manufactured by PerkinElmer).
Specifically, 1.0 mg of a measurement sample (crystalline polyester resin) is sealed in an aluminum pan (KITNO.B0143013), and this is set in a sample holder of “Diamond DSC” at a measurement temperature of 0 to 200 ° C. The temperature control of heating-cooling-heating is performed under the measurement conditions of a heating rate of 10 ° C./min and a cooling rate of 10 ° C./min, and the analysis is performed based on the second heating data.

The molecular weight of the crystalline polyester resin measured by gel permeation chromatography (GPC) is preferably 1,500 to 25,000 in terms of number average molecular weight (Mn).
The molecular weight measured by gel permeation chromatography (GPC) of the crystalline polyester resin is a value measured in the same manner as described above except that the crystalline polyester resin was used as a measurement sample.

The content of the crystalline polyester resin is preferably 5 to 30% by mass in the toner particles, and more preferably 5 to 20% by mass.
When the content ratio of the crystalline polyester resin is within the above range, the low temperature fixability can be reliably obtained.
When the content of the crystalline polyester resin is too small, there is a possibility that a sufficient low-temperature fixing effect cannot be obtained. On the other hand, when the content of the crystalline polyester resin is excessive, the hot offset resistance may be deteriorated.

  In the shell layer, the mass ratio of the amorphous polyester resin to the crystalline polyester resin is preferably 15:80 to 80:15.

The layer thickness of the shell layer is preferably 0.5 to 3.0 μm, more preferably 0.5 to 2.0 μm.
In the present invention, the thickness of the shell layer is a value measured by a transmission electron microscope (TEM).
Moreover, it is preferable that the content rate of resin which comprises a shell layer is 5-70 mass% with respect to resin which comprises a core particle.

[Colorant]
In the toner of the present invention, when the toner particles are configured to contain a colorant, the colorant may be contained in either the core particle or the shell layer.
Various known pigments and dyes can be used as the colorant.
Examples of carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. Examples of black iron oxide include magnetite, hematite, and iron iron trioxide.
Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95 and the like.
Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 48: 3, 53: 1, 57: 1, 81: 4, 122, 139, 144, 149, 150, 166, 177, 178, 222, 238, 269, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment yellow 14, 17, 74, 93, 94, 138, 155, 156, 158, 180, 185, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 60, and the like.
The colorant for obtaining the toner of each color can be used singly or in combination of two or more for each color.

  The content ratio of the colorant is preferably 1 to 10% by mass in the toner particles, and more preferably 2 to 8% by mass. If the content of the colorant is too small, the resulting toner may not have the desired coloring power. On the other hand, if the content of the colorant is excessive, it may be released to the colorant or to the carrier. May occur, which may affect the chargeability.

〔Release agent〕
In the toner of the present invention, when the toner particles are configured to contain a release agent, the release agent may be contained in any of the core particles and the shell layer.
Various known waxes can be used as the release agent.
As the wax, polyolefin waxes such as low molecular weight polypropylene, polyethylene, or oxidized polypropylene, polyethylene, and ester waxes such as behenate behenate can be preferably used.
Specifically, polyolefin waxes such as polyethylene wax and polypropylene wax; branched hydrocarbon waxes such as microcrystalline wax; long-chain hydrocarbon waxes such as paraffin wax and sazol wax; dialkyls such as distearyl ketone Ketone wax; carnauba wax, montan wax, behenate behenate, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanedioldi Ester wax such as stearate, trimellitic trimellitic acid, distearyl maleate; ethylenediamine behenylamide, trimellitic acid tristearylamide Such as amide waxes.
Among these, from the viewpoint of releasability during low-temperature fixing, it is preferable to use those having a low melting point, specifically, those having a melting point of 40 to 90 ° C.

  The content ratio of the release agent is preferably 1 to 20% by mass in the toner particles, and more preferably 3 to 15% by mass. When the content ratio of the release agent in the toner particles is in the above range, both the separation property and the fixing property can be reliably obtained.

[Charge control agent]
In the toner of the present invention, when the toner particles are configured to contain a charge control agent, the charge control agent may be contained in either the core particle or the shell layer.
Various known compounds can be used as the charge control agent.
The content of the charge control agent is preferably 0.1 to 10% by mass in the toner particles, and more preferably 0.5 to 5% by mass.

(External additive)
In the toner of the present invention, the toner particles can be used as toners as they are. However, in order to improve fluidity, chargeability, cleaning properties, etc., the toner particles may contain so-called fluidizing agents, cleaning aids, etc. An external additive may be added.
Various external additives may be used in combination.
The total addition amount of these external additives is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the toner particles.

[Toner glass transition point]
The toner of the present invention preferably has a glass transition point (Tg) of 30 to 70 ° C, more preferably 40 to 60 ° C.
When the glass transition point of the toner of the present invention is in the above range, sufficient low-temperature fixing property and heat-resistant storage property can be surely achieved. When the glass transition point of the toner is too small, the heat resistance (thermal strength) of the toner is lowered, and there is a possibility that sufficient heat storage stability and hot offset resistance cannot be obtained. Further, when the glass transition point of the toner is excessive, there is a possibility that sufficient low-temperature fixability cannot be obtained.

  The glass transition point of the toner is a value measured in the same manner as described above except that the toner is used as a measurement sample.

[Toner particle size]
In the toner of the present invention, the average particle diameter is preferably 3 to 8 μm, and more preferably 5 to 8 μm, for example, on a volume basis median diameter. This average particle size can be controlled by the concentration of the flocculant used during production, the amount of organic solvent added, the fusing time, the composition of the binder resin, and the like.
When the volume-based median diameter is in the above range, a very small dot image of 1200 dpi level can be faithfully reproduced.

The volume-based median diameter of the toner is measured and calculated using a measuring apparatus in which a computer system equipped with data processing software “Software V3.51” is connected to “Multisizer 3” (manufactured by Beckman Coulter). Value.
Specifically, 0.02 g of a measurement sample (toner) was added to 20 mL of a surfactant solution (for example, a surfactant obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing toner particles). Solution) and ultrasonically dispersed for 1 minute to prepare a toner dispersion, and this toner dispersion is a beaker containing “ISOTONII” (manufactured by Beckman Coulter) in a sample stand. Then, inject with a pipette until the displayed concentration of the measuring device is 8%. Here, a reproducible measurement value can be obtained by setting the concentration range. In the measurement apparatus, the measurement particle count is 25000, the aperture diameter is 100 μm, the frequency range is calculated by dividing the range of 2 to 60 μm, which is the measurement range, into 256, and the volume integrated fraction is 50 % Particle diameter is defined as the volume-based median diameter.

[Average circularity of toner]
In the toner of the present invention, the individual toner particles constituting the toner preferably have an average circularity of 0.930 to 1.000 from the viewpoints of stability of charging characteristics and low-temperature fixability. More preferably, it is 950 to 0.995.
When the average circularity is within the above range, the individual toner particles are less likely to be crushed, the contamination of the frictional charge imparting member is suppressed, the toner chargeability is stabilized, and the image quality of the formed image is high. It will be a thing.

The average circularity of the toner is a value measured using “FPIA-2100” (manufactured by Sysmex).
Specifically, the measurement sample (toner) was blended with an aqueous solution containing a surfactant, dispersed by performing ultrasonic dispersion for 1 minute, and then subjected to measurement conditions HPF by “FPIA-2100” (manufactured by Sysmex). In the (high magnification imaging) mode, photographing is performed at an appropriate density of 3,000 to 10,000 HPF detections, and the circularity of each toner particle is calculated according to the following formula (y). This is a value calculated by adding the degree and dividing by the total number of toner particles. If the number of HPF detections is in the above range, reproducibility can be obtained.
Formula (y): Circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)

(Developer)
The toner of the present invention can be used as a magnetic or non-magnetic one-component developer, but may be mixed with a carrier and used as a two-component developer. When the toner is used as a two-component developer, the carrier includes magnetic particles made of conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead. In particular, ferrite particles are preferable. Further, as the carrier, a coated carrier in which the surface of magnetic particles is coated with a coating agent such as a resin, a dispersion type carrier in which a magnetic fine powder is dispersed in a binder resin, or the like may be used.
The volume-based median diameter of the carrier is preferably 20 to 100 μm, more preferably 25 to 80 μm. The volume-based median diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

In the present invention, in order to confirm the ester group concentration of the crystalline polyester resin, it is necessary to extract the crystalline polyester resin contained in the toner particles. Specifically, the crystalline polyester resin can be extracted from the toner particles as follows.
First, the toner is dissolved in methyl ethyl ketone (MEK) at room temperature (20 ° C. or more and 25 ° C. or less). Here, the amorphous resin in the toner particles is dissolved in MEK at room temperature. Accordingly, since the MEK-soluble component contains an amorphous resin, the amorphous resin can be obtained from the supernatant separated by centrifugation after dissolution. On the other hand, the solid content after centrifugation is heated at 65 ° C. for 60 minutes, dissolved in tetrahydrofuran (THF), and filtered through a glass filter at 60 ° C., whereby a crystalline polyester resin is obtained from the filtrate. In addition, since crystalline polyester resin will precipitate if temperature falls during filtration by the said operation, it operates in the state kept warm.

  The ester group concentration of the crystalline polyester resin can be confirmed by hydrolyzing, measuring with P-GC / MS, specifying the acid and alcohol monomer types, and calculating the ester group concentration. .

[Toner Production Method]
The method for producing the toner of the present invention is not particularly limited, but is preferably a wet production method prepared in an aqueous medium, such as an emulsion polymerization aggregation method.
The method for producing the toner of the present invention by the emulsion polymerization aggregation method includes an aqueous dispersion in which fine particles of a binder resin (hereinafter also referred to as “binder resin fine particles”) are dispersed in an aqueous medium, and fine particles of a colorant. (Hereinafter also referred to as “colorant fine particles”) is mixed with an aqueous dispersion in which toner particles are dispersed, and the toner particles are formed by aggregating and thermally fusing the binder resin fine particles and the colorant fine particles. It is a method to do.

An example of a method for producing the toner of the present invention is specifically shown as follows:
(A) a step of preparing an aqueous dispersion in which fine particles of vinyl resin (hereinafter also referred to as “core resin fine particles”) are dispersed in an aqueous medium;
(B) a step of preparing an aqueous dispersion in which colorant fine particles are dispersed in an aqueous medium;
(C) a step of preparing an aqueous dispersion in which fine particles of an amorphous polyester resin and a crystalline polyester resin (hereinafter also referred to as “shell resin fine particles”) are dispersed in an aqueous medium;
(D) a step of aggregating and fusing the core resin fine particles and the colorant fine particles in an aqueous medium to form core particles;
(E) a step of aggregating and fusing the resin fine particles for shell on the surface of the core particles in an aqueous medium to form a shell layer to form toner particles;
(F) a step of controlling the toner particle shape by aging with heat energy;
(G) a step of cooling the dispersion of toner particles;
(H) separating the toner particles from the aqueous medium and removing the surfactant from the toner particles;
(I) drying the washed toner particles;
As necessary,
(J) A step of adding an external additive to the dried toner particles can be added.

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

(A) Preparation step of aqueous dispersion of core resin fine particles In this step, an aqueous dispersion of core resin fine particles using a vinyl resin is prepared.
The aqueous dispersion of the core resin fine particles can be prepared by a miniemulsion polymerization method using a vinyl monomer for obtaining a vinyl resin. That is, for example, a vinyl monomer is added to an aqueous medium containing a surfactant, mechanical energy is applied to form droplets, and then the radicals from the water-soluble radical polymerization initiator The polymerization reaction is allowed to proceed. Note that an oil-soluble polymerization initiator may be contained in the droplet. Thereby, the aqueous dispersion of the resin fine particles for cores by a vinyl resin can be prepared.
The core resin fine particles made of vinyl resin may have a multilayer structure of two or more layers made of vinyl resins having different compositions, and the core resin fine particles having such a structure have, for example, a two-layer structure. Then, a dispersion of resin fine particles is prepared by emulsion polymerization treatment (first-stage polymerization) according to a conventional method, a polymerization initiator and a vinyl monomer are added to this dispersion, and this system is polymerized (second treatment). (Stage polymerization).

[Surfactant]
As the surfactant used in this step, conventionally known various anionic surfactants, cationic surfactants, nonionic surfactants and the like can be used.

(Polymerization initiator)
As the polymerization initiator used in this step, various conventionally known polymerization initiators can be used. As specific examples of the polymerization initiator, for example, persulfates (potassium persulfate, ammonium persulfate, etc.) are preferably used. In addition, azo compounds (4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) salts, etc.), peroxide compounds, azobisisobutyronitrile, etc. Also good.

[Chain transfer agent]
In this step, a generally used chain transfer agent can be used for the purpose of adjusting the molecular weight of the vinyl resin. The chain transfer agent is not particularly limited, and examples thereof include mercaptans such as 2-chloroethanol, octyl mercaptan, dodecyl mercaptan, and t-dodecyl mercaptan, and styrene dimers.

The toner particles according to the present invention may contain other internal additives such as a release agent and a charge control agent as necessary, and such internal additives are used in this step, for example. It can be introduced into the toner particles by dissolving or dispersing in advance in a vinyl monomer solution for forming a vinyl resin.
In addition, such an internal additive is prepared by separately preparing a dispersion of internal additive fine particles consisting of only the internal additive, and aggregating the internal additive fine particles in the core particle forming step or the shell layer forming step, thereby forming toner particles. Although it can be introduced in, it is preferable to adopt a method of introducing in advance in this step.

The average particle diameter of the resin fine particles for core is preferably in the range of 20 to 500 nm in terms of volume-based median diameter.
The volume-based median diameter of the core resin fine particles is a value measured using “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.).

(B) Step of preparing aqueous dispersion of colorant fine particles This step is a step that is performed as necessary when toner particles containing a colorant are desired, and the colorant is finely divided in an aqueous medium. In which an aqueous dispersion of fine colorant particles is prepared.

The aqueous dispersion of colorant fine particles can be obtained by dispersing the colorant in an aqueous medium in which a surfactant is added to a critical micelle concentration (CMC) or higher.
The colorant can be dispersed using mechanical energy, and the disperser to be used is not particularly limited. However, an ultrasonic disperser, a mechanical homogenizer, a manton gourin or a pressure homogenizer is preferably used. Examples thereof include medium dispersers such as a pressure disperser, a sand grinder, a Getzman mill, and a diamond fine mill.

The colorant fine particles preferably have a volume-based median diameter of 10 to 300 nm in a dispersed state, more preferably 100 to 200 nm, and particularly preferably 100 to 150 nm.
The volume-based median diameter of the colorant fine particles is a value measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.).

(C) Step of preparing aqueous dispersion of resin fine particles for shell In this step, an aqueous dispersion of resin fine particles for shell using an amorphous polyester resin and a crystalline polyester resin is prepared. The resin fine particles for shell are in a state where fine particles of a crystalline polyester resin are contained or dispersed in an amorphous polyester resin.
The aqueous dispersion of resin fine particles for shells is prepared by first synthesizing an amorphous polyester resin and a crystalline polyester resin, and dissolving or dispersing these resins in an organic solvent to prepare an oil phase liquid. Is dispersed in an aqueous medium by phase inversion emulsification or the like to form oil droplets in a state controlled to a desired particle size, and then prepared by a method of removing the organic solvent.

The amount of the aqueous medium used is preferably 50 to 2,000 parts by mass and more preferably 100 to 1,000 parts by mass with respect to 100 parts by mass of the oil phase liquid.
A surfactant or the like may be added to the aqueous medium for the purpose of improving the dispersion stability of the oil droplets. As surfactant, the thing similar to what was mentioned in said process can be mentioned.

  The organic solvent used for the preparation of the oil phase liquid is preferably one having a low boiling point and low solubility in water from the viewpoint of easy removal treatment after formation of oil droplets. Examples thereof include methyl acetate, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene and the like. These can be used alone or in combination of two or more.

  The emulsification dispersion of the oil phase liquid can be performed using mechanical energy, and the disperser for performing the emulsification dispersion is not particularly limited, and a low-speed shear disperser, a high-speed shear disperser And a friction disperser, a high-pressure jet disperser, an ultrasonic disperser, and the like. Specific examples include a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).

The dispersion diameter of the oil droplets is preferably 60 to 1000 nm, and more preferably 80 to 500 nm.
The dispersion diameter of the oil droplets is a volume-based median diameter measured using a laser diffraction / scattering particle size distribution analyzer “LA-750” (manufactured by Horiba, Ltd.). The dispersion diameter of the oil droplets can be controlled by the magnitude of mechanical energy at the time of emulsification dispersion.

The average particle diameter of the resin fine particles for shell is preferably in the range of 20 to 500 nm in terms of volume-based median diameter.
The volume-based median diameter of the resin fine particles for shell is a value measured using “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.).

(D) Core particle formation step In this step, the core resin fine particles and the colorant fine particles are aggregated and further fused by heating to form core particles.
Specifically, a coagulant having a critical coagulation concentration or higher is added to an aqueous dispersion in which the above-mentioned fine particles are dispersed in an aqueous medium, and the particles are aggregated and fused by heating.

  The fusing temperature is preferably 60 to 95 ° C, for example.

[Flocculant]
The flocculant used in this step is not particularly limited, but those selected from metal salts such as alkali metal salts and alkaline earth metal salts are preferably used. Examples of the metal salt include monovalent metal salts such as sodium, potassium, and lithium; divalent metal salts such as calcium, magnesium, manganese, and copper; and trivalent metal salts such as iron and aluminum. Specific metal salts can include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, and the like. It is particularly preferable to use a divalent metal salt. These can be used individually by 1 type or in combination of 2 or more types.

The average particle diameter of the core particles is preferably in the range of 3 to 8 μm in terms of volume-based median diameter.
The volume-based median diameter of the core particles is a value measured using “Coulter Multisizer 3” (manufactured by Coulter Beckman).

(E) Shell Layer Forming Step In this step, the shell resin fine particles are aggregated on the core particles and further fused by heating to form a shell layer and toner particles.
Specifically, an aqueous dispersion in which the above-mentioned fine particles are dispersed in an aqueous dispersion of core particles is added, an aggregating agent having a critical aggregation concentration or more is added, and heating is performed to cause aggregation and fusion. As the flocculant, those described above can be used.

  The fusing temperature is preferably 60 to 95 ° C, for example.

(F) Ripening step This step is performed as necessary, and in the maturing step, the toner particles obtained in the shell layer forming step are aged by heat energy until a desired shape is obtained.
Specifically, the aging treatment is performed by heating and stirring the system in which the toner particles are dispersed, thereby adjusting the shape of the toner particles by a heating temperature, a stirring speed, a heating time and the like until a desired circularity is obtained. Done.

(G) Cooling Step This step is a step of cooling the toner particle dispersion. As conditions for the cooling treatment, it is preferable to cool at a cooling rate of 1 to 20 ° C./min. The specific method of the cooling treatment is not particularly limited, and examples include a method of cooling by introducing a refrigerant from the outside of the reaction vessel, a method of cooling by directly introducing cold water into the reaction system, and the like. it can.

(H) Filtration / Washing Step This step involves solid-liquid separation of the toner particles from the cooled dispersion of toner particles, and a toner cake obtained by solid-liquid separation (aggregating toner particles in a wet state in a cake form) This is a step of removing adhering substances such as a surfactant and an aggregating agent from the aggregate).
The solid-liquid separation is not particularly limited, and a centrifugal separation method, a vacuum filtration method using Nutsche or the like, a filtration method using a filter press, or the like can be used. Further, in washing, it is preferable to wash with water until the electric conductivity of the filtrate reaches 10 μS / cm.

(I) Drying Step This step is a step of drying the washed toner cake, and can be carried out according to a drying step in a generally-known method for producing toner particles.
Specifically, examples of the dryer used for drying the toner cake include a spray dryer, a vacuum freeze dryer, and a vacuum dryer, and a stationary shelf dryer, a mobile shelf dryer, a fluidized bed, and the like. It is preferable to use a dryer, a rotary dryer, a stirring dryer or the like.
The moisture of the dried toner particles is preferably 5% by mass or less, more preferably 2% by mass or less. In addition, when the dried toner particles are aggregated by a weak interparticle attractive force, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.

(J) External additive addition step This step is a step that is performed as necessary when an external additive is added to the toner particles.
The above toner particles can be used as toners as they are, but in order to improve fluidity, chargeability, cleaning properties, etc., external additives such as fluidizing agents and cleaning aids are added to the toner particles. You may use it in the state.
Various external additives may be used in combination.
The total addition amount of these external additives is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the toner particles.
As the external additive mixing device, a mechanical mixing device such as a Henschel mixer or a coffee mill can be used.

  In the toner of the present invention, excellent low-temperature fixability can be obtained because the shell layer contains a crystalline polyester resin with high thermal responsiveness. Particularly, the speed of copying machines and printers, embossed paper, etc. High fixability can be obtained even for paper types with large irregularities. In addition, the crystalline polyester resin is in a domain phase in the matrix phase, that is, the crystalline polyester resin is contained in the amorphous polyester resin in an incompatible state, thereby ensuring sufficient heat-resistant storage stability. can do. Further, since the core particles are made of a vinyl resin, the vinyl resin has a lower polarity than the polyester resin, so that the hygroscopic property of the whole toner is reduced and the environmental stability of the charged state can be obtained. .

  Although the embodiments of the present invention have been specifically described above, the embodiments of the present invention are not limited to the above examples, and various modifications can be made.

Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.
The measurement of the volume-based median diameter of the core resin fine particles, the colorant fine particles, and the shell resin fine particles, and the measurement of the molecular weight of the core resin, the amorphous polyester resin, and the crystalline polyester resin were performed as described above. .
Further, the measurement of the glass transition point (Tg) of the core resin, the amorphous polyester resin and the toner, and the measurement of the melting point of the crystalline polyester resin were performed as described above.
Further, the average diameter of the domain phase was measured as described above.
Furthermore, the carboxy group concentration or the ester group concentration of the crystalline polyester resin was calculated as described above.

[Toner Production Example 1]
(1) Preparation of aqueous dispersion of resin fine particles for core (1-1) First stage polymerization An anionic surfactant in advance in a reaction vessel equipped with a stirrer, temperature sensor, temperature controller, cooling pipe and nitrogen introducing device An anionic surfactant solution prepared by dissolving 2.0 parts by mass of “sodium lauryl sulfate” in 2900 parts by mass of ion-exchanged water was added, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. I let you. After adding 9.0 parts by mass of a polymerization initiator “potassium persulfate (KPS)” to this anionic surfactant solution and adjusting the internal temperature to 78 ° C., 540 parts by mass of styrene and 154 parts by mass of n-butyl acrylate A monomer solution [1] consisting of 77 parts by mass of methacrylic acid and 17 parts by mass of n-octyl mercaptan was added dropwise over 3 hours. After completion of the dropping, polymerization (first stage polymerization) was carried out by heating and stirring at 78 ° C. for 1 hour to prepare a dispersion of resin fine particles [a1].

(1-2) Second-stage polymerization In a flask equipped with a stirrer, a solution consisting of 94 parts by mass of styrene, 27 parts by mass of n-butyl acrylate, 6 parts by mass of methacrylic acid and 1.7 parts by mass of n-octyl mercaptan. Then, 51 parts by mass of a release agent “paraffin wax (melting point: 73 ° C.)” was added, and the mixture was heated to 85 ° C. and dissolved to prepare a monomer solution [2].
On the other hand, a surfactant solution in which 2 parts by mass of the anionic surfactant “sodium lauryl sulfate” was dissolved in 1100 parts by mass of ion-exchanged water was heated to 90 ° C., and the resin fine particles [a1 Is added in an amount of 28 parts by mass in terms of solid content of the resin fine particles [a1], and then the monomer solution [Cleamix] (manufactured by M Technique Co., Ltd.) having a circulation path is used. 2] is mixed and dispersed for 4 hours to prepare a dispersion containing emulsified particles having a dispersion diameter of 350 nm. In this dispersion, 2.5 parts by mass of the polymerization initiator “KPS” is dissolved in 110 parts by mass of ion-exchanged water. An aqueous initiator solution was added, and this system was heated and stirred at 90 ° C. for 2 hours to conduct polymerization (second stage polymerization), whereby a dispersion of resin fine particles [a11] was prepared.

(1-3) Third-stage polymerization To the dispersion of the resin fine particles [a11], an initiator aqueous solution in which 2.5 parts by mass of a polymerization initiator “KPS” is dissolved in 110 parts by mass of ion-exchanged water, A monomer solution [3] consisting of 230 parts by mass of styrene, 78 parts by mass of n-butyl acrylate, 16 parts by mass of methacrylic acid, and 4.2 parts by mass of n-octyl mercaptan under a temperature condition of 80 ° C. takes 1 hour. And dripped. After completion of the dropping, polymerization (third stage polymerization) was performed by heating and stirring for 3 hours. Then, it cooled to 28 degreeC and prepared the aqueous dispersion [M1] of the resin fine particles for cores by a vinyl resin. The average particle diameter of the resin fine particles for core is a volume-based median diameter of 250 nm, the glass transition point (Tg) is 45 ° C., the softening point (Tsp) is 100 ° C., and the weight average molecular weight (Mw) is 33,000. there were.

(2) Preparation of Aqueous Dispersion of Colorant Fine Particles 90 parts by mass of sodium dodecyl sulfate was dissolved in 1600 parts by mass of ion-exchanged water, and while stirring this solution, carbon black “Mogal L” (manufactured by Cabot Corporation) 420 parts by mass The aqueous dispersion liquid [C] of colorant fine particles was prepared by gradually adding a part, and then dispersing using a stirrer “CLEARMIX” (M Technique Co., Ltd.). The average particle diameter of the colorant fine particles was 117 nm as a volume-based median diameter.

(3) Preparation of aqueous dispersion of resin fine particles for shell (3-1) Synthesis of amorphous polyester resin [A1] Four-neck with a capacity of 10 liters equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple In a flask, 500 parts by mass of a bisphenol A propylene oxide 2-mole adduct, 114 parts by mass of terephthalic acid, 79 parts by mass of fumaric acid, 22 parts by mass of trimellitic acid, and 2 parts by mass of an esterification catalyst (tin octylate) were added. For 8 hours, and further for 1 hour at 8 kPa, thereby obtaining an amorphous polyester resin [A1]. The amorphous polyester resin [A1] had a glass transition point (Tg) of 60 ° C., a softening point (Tsp) of 105 ° C., and a weight average molecular weight (Mw) of 45,000.

(3-2) Synthesis of crystalline polyester resin [C1] In a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introducing device, 300 parts by mass of polycarboxylic acid “sebacic acid” and polyhydric alcohol After charging 170 parts by mass of “1,6-hexanediol”, the internal temperature was raised to 190 ° C. over 1 hour while stirring this system, and after confirming that the system was uniformly stirred, Ti (OBu) ₄ was added in an amount of 0.003% by mass based on the charged amount of polyvalent carboxylic acid. Thereafter, the internal temperature is raised from 190 ° C. to 240 ° C. over 6 hours while distilling off the generated water, and the dehydration condensation reaction is continued over 6 hours under the condition of a temperature of 240 ° C. for polymerization. As a result, a crystalline polyester resin [C1] was obtained. The crystalline polyester resin [C1] had a melting point (Tm) of 66.8 ° C. and a number average molecular weight (Mn) of 6,300.

(3-3) Preparation of Aqueous Dispersion of Resin Fine Particles for Shell 20 parts by mass of the amorphous polyester resin [A1] and 10 parts by mass of the crystalline polyester resin [C1] are melted and left in the molten state. It was transferred to Cavitron CD1010 "(manufactured by Eurotech Co., Ltd.) at a transfer rate of 100 parts by mass per minute. In addition, simultaneously with the transfer of the amorphous polyester resin [A1] and the crystalline polyester resin [C1] in the molten state, 70 parts by mass of reagent ammonia water is added with ion-exchanged water in the aqueous solvent tank to the emulsification disperser. The diluted diluted aqueous ammonia having a concentration of 0.37% by mass was transferred at a transfer rate of 0.1 liter per minute while being heated to 100 ° C. with a heat exchanger. Then, by operating this emulsification disperser under the conditions of a rotor rotational speed of 60 Hz and a pressure of 5 kg / cm ² , an aqueous dispersion of shell resin fine particles having a volume-based median diameter of 200 nm and a solid content of 30 parts by mass. A liquid [S1] was prepared.

(4) Formation of toner particles Into a reaction vessel equipped with a stirrer, a temperature sensor, and a cooling tube, 252 parts by mass of an aqueous dispersion [M1] of resin fine particles for cores in terms of solid content and 2000 parts by mass of ion-exchanged water are charged. The pH was adjusted to 10 by adding a 5 mol / liter sodium hydroxide aqueous solution. Thereafter, 40 parts by mass of an aqueous dispersion [C] of colorant fine particles was added in terms of solid content, and then an aqueous solution in which 60 parts by mass of magnesium chloride was dissolved in 60 parts by mass of ion-exchanged water was stirred at 30 ° C. for 10 parts. Added over a minute. Thereafter, the temperature was raised after being allowed to stand for 3 minutes, and the temperature of the system was raised to 80 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 80 ° C. In this state, the particle diameter of the core particles was measured with “Coulter Multisizer 3” (manufactured by Coulter Beckman), and when the volume-based median diameter (D50) reached 6.0 μm, Aqueous dispersion [S1] was added in an amount of 108 parts by mass in terms of solid content over 30 minutes, and when the supernatant of the reaction solution became transparent, an aqueous solution in which 190 parts by mass of sodium chloride was dissolved in 760 parts by mass of ion-exchanged water. Was added to stop grain growth. Further, the temperature is raised and the mixture is heated and stirred in a state of 90 ° C. to advance the fusing of the particles, and the average circularity measurement apparatus “FPIA-2100” (manufactured by Sysmex) is used (HPF detection). When the average circularity reached 0.945, the mixture was cooled to 30 ° C. to obtain an aqueous dispersion of toner particles [1].
This aqueous dispersion of toner particles [1] is solid-liquid separated with a centrifuge to form a wet cake of toner particles, and this is kept at 35 ° C. until the electric conductivity of the filtrate reaches 5 μS / cm. After washing with ion-exchanged water, it was transferred to a “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.) and dried until the water content became 0.5 mass%.
To the dried toner particles [1], 1% by mass of hydrophobic silica (number average primary particle size = 12 nm) and 0.3% by mass of hydrophobic titania (number average primary particle size = 20 nm) are added, and a Henschel mixer is used. By mixing, Toner [1] was produced.

With respect to the toner [1] obtained as described above, the toner particles dyed with ruthenium oxide (VIII) are cut, and the cross section of the toner particles is shown in a field emission transmission electron microscope “FE-TEM (model number JEM-2010F)” ( (Manufactured by JEOL).
In the TEM image, a core-shell structure was confirmed, and a domain-matrix structure was confirmed in the shell layer. The average diameter of the domain phase was 248 nm.

[Toner Production Examples 2 to 13]
Toners [2] to [13] were obtained in the same manner as in Toner Production Example 1, except that the type and amount of each aqueous dispersion were changed according to Table 1.

In Table 1, the aqueous dispersions [M2] to [M3] of the core resin fine particles are obtained by the following preparation examples.
In Table 1, the aqueous dispersions [S2] to [S10] of the resin fine particles for shells are amorphous materials used in the preparation of the aqueous dispersion of (3-3) shell fine resin particles in Production Example 1 of the toner. It was obtained by changing the types and addition amounts of the crystalline polyester resin and the crystalline polyester resin according to Table 2. The aqueous dispersion [S11] of the resin fine particles for shell is obtained by the following preparation example. In Table 2, the amorphous polyester resin [A2] is (3- 1) It was obtained by changing the type of monomer according to Table 3 in the synthesis of the amorphous polyester resin. Further, the amorphous polyester resin [A3] is a vinyl-modified amorphous polyester resin, and is obtained by the following production example.
Furthermore, in Table 2, the crystalline polyester resins [C2] to [C3] are obtained by changing the types of monomers according to Table 4 in the synthesis of (3-2) crystalline polyester resin in Toner Production Example 1. It is obtained.

[Preparation of aqueous dispersion [M2] of resin fine particles for core]
In preparation of the aqueous dispersion of the resin fine particles for core (1) in toner production example 1, the same procedure except that 76 parts by mass of the crystalline polyester resin [C1] is added together with the release agent during the second stage polymerization. Thus, an aqueous dispersion [M2] of resin fine particles for core was obtained. The average particle diameter of the resin fine particles for core is 275 nm in volume-based median diameter, the glass transition point (Tg) is 42 ° C., the softening point (Tsp) is 92 ° C., and the weight average molecular weight (Mw) is 31,500. there were.

[Preparation of aqueous dispersion of resin fine particles for core [M3]]
In a 10-liter four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer and a thermocouple, 500 parts by mass of bisphenol A propylene oxide 2 mol adduct, 120 parts by mass of terephthalic acid, 84 parts by mass of fumaric acid, 6 parts by weight of merit acid and 2 parts by weight of an esterification catalyst (tin octylate) are added, subjected to a polycondensation reaction at 230 ° C. for 8 hours, and further reacted at 8 kPa for 1 hour to obtain an amorphous polyester resin for the core. It was. The amorphous polyester resin for core had a glass transition point (Tg) of 54 ° C., a softening point (Tsp) of 103 ° C., and a weight average molecular weight (Mw) of 32,000.
100 parts by mass of the obtained amorphous polyester resin for the core and 11 parts by mass of the release agent “paraffin wax (melting point: 73 ° C.)” were pulverized with “Landel mill type: RM” (manufactured by Tokuju Kosakusha) It is mixed with 638 parts by mass of a sodium lauryl sulfate solution having a concentration of 0.26% by mass prepared in advance and stirred for more than 30 minutes at V-LEVEL of 300 μA using an ultrasonic homogenizer “US-150T” (manufactured by Nippon Seiki Seisakusho). Sonication was performed to obtain an aqueous dispersion [M3] of core resin fine particles having a volume-based median diameter (D ₅₀ ) of 250 nm.

[Preparation of aqueous dispersion of resin fine particles for shell [S11]]
An anion obtained by dissolving 2.0 parts by mass of anionic surfactant “sodium lauryl sulfate” in 2900 parts by mass of ion-exchanged water in a reaction vessel equipped with a stirrer, a temperature sensor, a temperature controller, a cooling pipe, and a nitrogen introducing unit. The internal temperature was raised to 80 ° C. while charging the neutral surfactant solution and stirring at a stirring speed of 230 rpm under a nitrogen stream. After adding 9.0 parts by mass of a polymerization initiator “potassium persulfate (KPS)” to this anionic surfactant solution and adjusting the internal temperature to 78 ° C., 540 parts by mass of styrene and 177 parts by mass of n-butyl acrylate A monomer solution consisting of 120 parts by mass of methacrylic acid and 23 parts by mass of n-octyl mercaptan was added dropwise over 3 hours. After completion of dropping, the mixture was heated and stirred at 78 ° C. for 1 hour to obtain an aqueous dispersion [S11] of resin particles for shells. The resin fine particles for shell had a glass transition point (Tg) of 54 ° C., a softening point (Tsp) of 115 ° C., and a weight average molecular weight (Mw) of 18,000.

[Synthesis of vinyl-modified amorphous polyester resin [A3]]
The following both reactive monomers, a vinyl monomer for forming a vinyl polymerization segment, and a radical polymerization initiator were placed in a dropping funnel.
9 parts by weight of acrylic acid 125 parts by weight of styrene 45 parts by weight of butyl acrylate 16 parts by weight of polymerization initiator (di-t-butyl peroxide) In a 10 liter four-necked flask equipped with a stirrer and a thermocouple.
Bisphenol A propylene oxide 2-mole adduct 500 parts by weight Terephthalic acid 114 parts by weight Fumaric acid 79 parts by weight Trimellitic acid 22 parts by weight Esterification catalyst (tin octylate) 1.5 parts by weight The temperature is increased to 170 ° C. which is the addition polymerization reaction temperature The mixture was warmed and the vinyl monomer was dropped from the previous dropping funnel over 90 minutes with stirring, followed by aging for 60 minutes.
Thereafter, 40 g of tin octylate was added as an esterification catalyst, the temperature was raised to 235 ° C., and the mixture was reacted at normal pressure (101.3 kPa) for 5 hours and further under reduced pressure (8 kPa) for 1 hour.
Next, after cooling to 200 ° C., the reaction was performed under reduced pressure (20 kPa) until the desired softening point was reached to obtain an amorphous polyester resin [A3].
The amorphous polyester resin [A3] had a glass transition point (Tg) of 58 ° C., a softening point (Tsp) of 105 ° C., and a weight average molecular weight (Mw) of 53,000.

[Developer Production Examples 1 to 13]
To each of the toners [1] to [13], a ferrite carrier having a volume-based median diameter of 60 μm coated with a silicone resin is added so that the toner concentration becomes 6% by mass, and mixed by a V-type mixer. As a result, developers [1] to [13] were produced.

[Examples 1 to 9, Comparative Examples 1 to 4]
(1) Evaluation of low-temperature fixability In the copying machine “bizhub PRO C6550” (manufactured by Konica Minolta Co., Ltd.), the fixing device can change the surface temperature (fixing temperature) of the heating roller in the range of 120 to 200 ° C. The developers [1] to [13] were respectively mounted. A fixing experiment in which a solid image having a toner adhesion amount of 8 mg / cm ² is fixed on A4 size high-quality paper and embossed paper in an environment of normal temperature and humidity (temperature 20 ° C., humidity 50% RH) is set fixing temperature. Was repeated from 120 ° C. to 200 ° C. while changing in increments of 5 ° C.
Among fixing experiments in which image smear due to low temperature offset is not visually observed, the fixing temperature of the fixing experiment relating to the lowest fixing temperature was evaluated as the minimum fixing temperature. The results are shown in Table 5. In addition, it is judged that the lower limit fixing temperature is 140 ° C. or lower.

(2) Evaluation of heat-resistant storage For each of the toners [1] to [13], 0.5 g of the toner is placed in a 10 mL glass bottle with an inner diameter of 21 mm, the lid is closed, and tap denser “KYT-2000” (Seishin Enterprise Co., Ltd.) The product was shaken 600 times at room temperature and then left for 2 hours in an environment with a temperature of 55 ° C. and a humidity of 35% RH with the lid removed. Next, the toner is placed on a sieve of 48 mesh (350 μm per day) with care not to break up the toner aggregates, set on a powder tester (manufactured by Hosokawa Micron), and fixed with a press bar and knob nut. After adjusting the vibration intensity to a feed width of 1 mm and applying vibration for 10 seconds, the amount of residual toner remaining on the sieve was measured, and the toner aggregation rate was calculated by the following formula (2) and evaluated. The results are shown in Table 5.
Formula (2): toner aggregation rate (mass%) = {residual toner amount (g) /0.5 (g)} × 100
In addition, the case where the toner aggregation rate is less than 15% by mass is judged to be excellent, and the case where the toner aggregation rate is 15% by mass or more and 20% by mass or less is judged to be good. It is judged.

(3) Evaluation of environmental stability of charged state Developers [1] to [13] were mounted on a copier “bizhub PRO C6550” (manufactured by Konica Minolta). After performing continuous printing of 1000 sheets of images with a printing rate of 20% in a low temperature and low humidity environment (10 ° C., 15% RH) and a high temperature and high humidity environment (30 ° C., 85% RH), 10 solid image portions each. And a white background part using a Macbeth reflection densitometer “RD-918” to measure a solid image part density difference between a high temperature and high humidity environment (HH) and a low temperature and low humidity environment (LL) and an average density difference between the white background part did.
The difference in the average density of the solid image area between the high-temperature and high-humidity environment and the low-temperature and low-humidity environment is less than 0.10. It was.

10 Toner particle 11 Core particle 12 Shell layer 12a Matrix phase 12b Domain phase

Claims (5)

In the electrostatic charge image developing toner comprising toner particles having a core-shell structure in which a shell layer is coated on the surface of the core particles,
The core particle contains a vinyl resin,
The shell layer contains an amorphous polyester resin and a crystalline polyester resin, and the crystalline polyester resin is dispersed as a domain phase in a matrix phase of the amorphous polyester resin. An electrostatic charge image developing toner.   The electrostatic image developing toner according to claim 1, wherein an average diameter of the domain phase is 0.15 to 1 μm.   The electrostatic charge image developing toner according to claim 1, wherein the crystalline polyester resin has an ester group concentration of 0.1 to 7.5 mmol / g.   The electrostatic image developing toner according to claim 1, wherein the amorphous polyester resin is vinyl-modified.   The electrostatic charge image developing toner according to claim 1, wherein a content ratio of the crystalline polyester resin in the toner particles is 5 to 30% by mass.

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