JP2015011304A - Toner for electrostatic charge image development, and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development that provides excellent low-temperature fixability and has high heat-resistant storage property and fixing separability, and can form images in which the occurrence of uneven glossiness is suppressed; and a manufacturing method of the same.SOLUTION: In a toner for electrostatic charge image development composed of toner particles having a core-shell structure in which the surface of core particles is coated with a shell layer, the core particles contain a crystalline polyester resin; the shell layer contains a vinyl resin and mold release agent; and a mass ratio between the crystalline polyester resin and vinyl resin is 95:5 to 60:40.

Description

  The present invention relates to an electrostatic image developing toner used for electrophotographic image formation and a method for producing the same.

  In recent years, in order to further save energy in an electrophotographic image forming apparatus, an electrostatic image developing toner (hereinafter also simply referred to as “toner”) that is thermally fixed at a lower temperature is required. ing.

In response to such a demand for low-temperature fixing, for example, Patent Document 1 discloses a toner using a crystalline polyester resin as a binder resin.
However, in this toner, since the binder resin is composed only of a crystalline polyester resin, the toner has excellent low-temperature fixability, but there is a problem that fixing separation properties are reduced due to the compatibilization of the binder resin and the release agent. . Further, there is a problem that unevenness of gloss occurs in the formed image due to recrystallization of crystalline components such as a crystalline polyester resin and a release agent after heat fixing.

For example, Patent Document 2 discloses a toner in which a crystalline polyester resin is contained in an amorphous resin.
In this toner, since the crystalline polyester resin and the amorphous resin are in a compatible relationship, the recrystallization of the crystalline component can be suppressed and the occurrence of uneven gloss can be suppressed. Since the resin content is relatively small, there is a problem that sufficient low-temperature fixability cannot be obtained.

  In addition, in any of the toners described in Patent Document 1 and Patent Document 2, there is a problem that high heat-resistant storage stability cannot be obtained because a crystalline polyester resin having a characteristic of being easily melted at a low temperature is used.

In recent years, by adopting a core-shell structure and the combined use of amorphous and crystalline components, the low-temperature fixability due to the crystalline component and the heat-resistant storage stability, fixing separation property, and image quality due to the amorphous component are functionally separated. Has been proposed.
For example, in Patent Document 3, in a toner having a core-shell structure, a core particle contains a crystalline polyester resin and an amorphous resin, and a shell layer is made of an amorphous resin having a composition different from that of the amorphous resin of the core particle. It is disclosed that it contains. In this toner, while the low-temperature fixability is obtained by the crystalline polyester resin, the heat-resistant storage stability is obtained by providing a shell layer made of a resin having high heat resistance.
However, in this toner, the release agent is contained in the core particles, and the presence of a shell layer made of a resin having high heat resistance reduces the exudability of the release agent, resulting in high fixing separation properties. There is a problem that cannot be obtained.

Further, for example, Patent Document 4 discloses a toner in which a crystalline polyester resin and an amorphous polyester resin are contained in a core particle, and vinyl resin fine particles are adhered to the core particle surface in an island shape. Yes. In Patent Document 4, by making the vinyl resin incompatible with the resin forming the core particles adhere to the surface of the core particles in an island shape, the release agent contained in the core particles can be easily exuded, It is said that fixing separation can be obtained. In addition, in the core particle, the main component is an amorphous polyester resin other than the crystalline polyester resin, thereby suppressing recrystallization of the crystalline polyester resin after heat fixing and suppressing occurrence of uneven gloss. I can do it.
However, this toner has a problem that high heat-resistant storage stability cannot be obtained because core particles made of a resin having a characteristic of being easily melted at a low temperature are partially exposed.

  Further, in any of the toners described in Patent Document 3 and Patent Document 4, since the content ratio of the crystalline component is relatively small, there is a problem that excellent low-temperature fixability cannot be obtained.

Japanese Patent No. 4032940 JP 2011-70001 A JP 2012-2833 A JP 2011-123483 A

  The present invention has been made in consideration of the circumstances as described above, and its purpose is to obtain high heat storage stability and fixing separability while obtaining excellent low-temperature fixability, and gloss An object of the present invention is to provide a toner for developing an electrostatic image capable of forming an image in which occurrence of unevenness is suppressed, and a method for producing the same.

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 particles contain a crystalline polyester resin,
The shell layer contains a vinyl resin and a release agent,
The mass ratio of the crystalline polyester resin and the vinyl resin is 95: 5 to 60:40.

In the electrostatic image developing toner of the present invention, the ester group concentration of the crystalline polyester resin is 0.1 to 7.5 mmol / g,
The vinyl resin preferably has a carboxy group concentration of 0.2 to 1.0 mmol / g.

  In the electrostatic image developing toner of the present invention, the content of the release agent in the toner particles is preferably 0.5 to 5% by mass.

The method for producing an electrostatic image developing toner of the present invention is a method for producing the above-described electrostatic image developing toner,
It has a step of preparing an aqueous dispersion of resin fine particles containing a release agent and a vinyl resin by a miniemulsion polymerization method using a vinyl monomer and a release agent for forming the vinyl resin. To do.

  According to the toner for developing an electrostatic charge image of the present invention, the toner particle has a core-shell structure in which a core layer containing a crystalline polyester resin is coated with a shell layer containing a vinyl resin and a release agent. In addition, when the mass ratio of the crystalline polyester resin and the vinyl resin is in a specific range, while having excellent low-temperature fixability, high heat storage stability and fixing separability are obtained, and uneven glossiness is obtained. It is possible to form an image in which the occurrence of this is suppressed.

  According to the method for producing a toner for developing an electrostatic charge image of the present invention, the toner can be easily obtained by preparing a resin fine particle containing a release agent and a vinyl resin, which is produced by a miniemulsion polymerization method. Can be manufactured.

  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 a release agent, and the toner particles contain other internal additives such as a colorant, magnetic powder, and a charge control agent as desired. 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 the core particle surface is coated with a shell layer. Specifically, the toner particles have a structure in which the core particle surface containing a crystalline polyester resin is coated with a shell layer containing a vinyl resin and a release agent. In the shell layer, the release agent is contained as a domain phase in the matrix phase made of vinyl resin.
The toner particles having the core-shell structure are preferably those in which the core particle surfaces are completely covered with the shell layer, but the core particle surfaces may be partially exposed.

  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 of the present invention, the mass ratio of the crystalline polyester resin constituting the core particles and the vinyl resin constituting the shell layer is 95: 5 to 60:40, more preferably 90:10 to 80:20. It is said.
When the mass ratio of the crystalline polyester resin and the vinyl resin is within the above range, excellent low-temperature fixability can be obtained.
When the content ratio of the crystalline polyester resin is excessively large, the content ratio of the vinyl resin becomes excessively small, so that the shell layer cannot be formed on the surface of the core particle, and there is a possibility that high heat storage stability cannot be obtained. On the other hand, when the content ratio of the crystalline polyester resin is too small, there is a possibility that excellent low-temperature fixability cannot be obtained.

  That is, in the toner of the present invention, the crystalline polyester resin is contained in a high ratio in the toner particles, that is, the toner has a main component. In addition, since the release agent is contained in the shell layer, the crystalline polyester resin of the core particles and the release agent are difficult to be compatible with each other. Separability is obtained. Further, since the resin constituting the shell layer is a vinyl resin, high heat-resistant storage stability is obtained, and when the vinyl resin and the crystalline polyester resin are mixed at the time of heat fixing, the crystalline polyester resin is recrystallized. Therefore, it is possible to form an image in which occurrence of gloss unevenness is suppressed.

[Binder resin]
The binder resin constituting the toner particles according to the present invention is composed of the crystalline polyester resin contained in the core particles and the vinyl resin contained in the shell layer, but may contain other resins. Good. Specifically, the core particles may contain other resins as long as the crystalline polyester resin is contained in a proportion of 50% by mass or more in the total resin (binder resin) constituting the toner particles. Good. Examples of other resins include vinyl resins and amorphous polyester resins.

(Crystalline polyester resin)
The crystalline polyester resin constituting the core particles is a main component (for example, 50% by mass or more) in the binder resin in the toner particles.

  The crystalline polyester resin is a differential scanning calorimetry measurement among known polyester resins obtained by polycondensation reaction of a divalent or higher carboxylic acid (polyvalent carboxylic acid) and a divalent or higher alcohol (polyhydric alcohol) ( DSC) 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 4.0 to 6.0 mmol / g.
When the ester group concentration of the crystalline polyester resin is in the above range, the crystalline polyester resin becomes incompatible with the vinyl resin before heat fixing in relation to the carboxy group concentration of the vinyl resin described later, At the time of fixing, the crystalline polyester resin is compatible with the vinyl resin. Accordingly, since the crystalline polyester resin and the vinyl resin are not compatible before heat fixing, the crystalline polyester resin does not advance the plasticization of the vinyl resin, so that high heat storage stability is obtained. In addition, the crystalline polyester resin and the vinyl resin are compatibilized at the time of heat fixing, so that recrystallization of the crystalline polyester resin can be suppressed after heat fixing, and an image in which the occurrence of uneven glossiness is suppressed can be obtained. It can form more reliably.

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 structure of the polyvalent carboxylic acid and polyhydric alcohol constituting the crystalline polyester resin.

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 of the crystalline polyester resin is preferably 60 to 90 ° C, more preferably 70 to 85 ° C. The melting point of the crystalline polyester resin is lower than the softening point of the vinyl resin B described later.
When the melting point of the crystalline polyester resin is in the above range, sufficient low-temperature fixability can 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 2,000 to 25,000 in terms of number average molecular weight (Mn).

The molecular weight 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 (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 carrier solvent, detected using a refractive index detector (RI detector), and the molecular weight distribution of the measurement sample. Using a calibration curve measured using monodisperse polystyrene standard particles Calculated. Ten polystyrenes were used for calibration curve measurement.

The content of the crystalline polyester resin is preferably 50% by mass or more, more preferably 70 to 90% by mass in the total resin (binder resin) constituting the toner particles.
When the content ratio of the crystalline polyester resin is within the above range, the low temperature fixability can be reliably obtained. That is, it is expected to contribute to the prevention of occurrence of uneven gloss in addition to the contribution to improving the low temperature fixability.

(Vinyl resin)
The vinyl resin constituting the shell layer 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 7% 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.

The carboxy group concentration of the vinyl resin is preferably 0.2 to 1.0 mmol / g, more preferably 0.5 to 0.8 mmol / g.
When the carboxy group concentration of the vinyl resin is within the above range, the vinyl resin becomes incompatible with the crystalline polyester resin before heat fixing in relation to the ester group concentration of the crystalline polyester resin, and at the time of heat fixing In this case, the vinyl resin is compatible with the crystalline polyester resin. Accordingly, since the vinyl resin and the crystalline polyester resin are not compatibilized before heat fixing, the crystalline polyester resin does not advance plasticization of the vinyl resin, and thus high heat-resistant storage stability is obtained. In addition, since the vinyl resin and crystalline polyester resin are compatible during heat fixing, recrystallization of the crystalline polyester resin can be suppressed, and an image with reduced gloss unevenness can be formed more reliably. can do.
Further, when the carboxy group concentration of the vinyl resin is in the above range, plasticization of the resin is avoided, so that the elasticity of the toner is maintained in a good state. As a result, it is considered that it contributes to maintaining high fixing separation property.

Here, the carboxy group concentration is the ratio of carboxy groups in the vinyl resin, and indicates the degree of affinity for water. The larger the value, the higher the affinity for water.
In the present invention, the carboxy group concentration is a value calculated by the following formula (2).
Formula (2): Carboxy group concentration = [total number of moles of carboxy groups / (molecular weight of monomers forming vinyl resin × mol fraction)] × 1000
The carboxy group concentration of the vinyl resin can be controlled by the introduction ratio of the monomer having a carboxy group.

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

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 20,000 to 200,000 in terms of weight average molecular weight (Mw), more preferably 40,000 to 100,000.
When the weight average molecular weight of the vinyl resin is within the above range, the low temperature fixability can be sufficiently ensured, and the heat resistance (thermal strength) of the toner is sufficiently ensured. It is thought that it contributes to the improvement of hot offset resistance.

  The molecular weight measured by gel permeation chromatography (GPC) of vinyl resin is a value measured in the same manner as described above except that vinyl resin was used as a measurement sample.

The content ratio of the vinyl resin is preferably 9 to 18% by mass in the binder resin.
When the content ratio of the vinyl resin is within the above range, the gloss unevenness can be suppressed by having good heat storage stability and being compatible with the crystalline polyester resin.

[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, but is contained in the core particle. It is preferable.
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, the release agent is contained in the shell layer. When the release agent is contained in the shell layer, it becomes difficult to be compatible with the crystalline polyester resin contained in the core particles, and it is easy to ooze out during heat fixing, so that high fixing separation property is obtained.
The release agent is dispersed as a domain phase in a matrix phase made of vinyl resin, and the average diameter of the domain phase is, for example, 0.05 to 2 μm. 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 the TEM, the diameter of each domain phase is set to a horizontal ferret diameter and a vertical ferret diameter. The average value of the diameters of the domain phases is calculated as the average value of the domain phases.

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 of the release agent is preferably 0.5 to 5% by mass in the toner particles, and more preferably 3 to 5% by mass.
Even if the content of the release agent in the toner particles is smaller than the conventional range as described above, the release agent is contained in the shell layer, making it difficult to be compatible with the crystalline polyester resin in the core particles. In addition, the release agent is likely to ooze out, and high fixing separation property can be 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 to 5% by mass in the toner particles, and more preferably 0 to 0.5% 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 50 to 70 ° C, more preferably 55 to 65 ° 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. In addition, since the glass transition point of the toner is in the above range, the heat resistance (thermal strength) of the toner is maintained, and as a result, sufficient heat storage stability and hot offset resistance can be reliably obtained. Be expected.

[Melting point of toner]
The toner of the present invention preferably has a melting point (Tm) of 60 to 90 ° C, more preferably 65 to 80 ° C.
When the melting 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 reliably achieved. In addition, by setting the melting point of the toner within the above range, it is expected that the heat resistance (thermal strength) of the toner is maintained well, and thereby sufficient heat storage stability can be secured.

  The glass transition point and melting point of the toner are values measured in the same manner as described above except that the toner was 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 average particle diameter of the carrier is preferably 20 to 100 μm, more preferably 25 to 80 μm in terms of volume-based median diameter.
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 carboxy group concentration of the vinyl resin and the ester group concentration of the crystalline polyester resin, it is necessary to extract the vinyl resin and the crystalline polyester resin contained in the toner particles. Specifically, the 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 vinyl resin in the toner particles is dissolved in MEK at room temperature. Accordingly, since the vinyl resin is contained in the MEK soluble matter, the vinyl resin can be obtained from the supernatant liquid 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 carboxy group concentration of the vinyl resin can be confirmed by, for example, 12C-NMR (nuclear magnetic resonance) measurement using deuterated chloroform. Specifically, the peak of the carbon atom derived from each monomer is assigned, the monomer type and composition ratio are specified, and the carboxy group concentration is calculated.
In addition, the ester group concentration of the crystalline polyester resin should be confirmed by hydrolyzing, measuring with P-GC / MS, specifying the acid and alcohol monomer types, and calculating the ester group concentration. Can do.

  In the toner described above, the crystalline polyester resin is contained in a high ratio in the toner particles, that is, it is a main component, so that basically excellent low-temperature fixability can be obtained. In addition, since the release agent is contained as a domain phase in the shell layer until it melts and exudes by heat during heat fixing, it becomes difficult to be compatible with the crystalline polyester resin of the core particle. The mold release agent easily oozes out during fixing, and high fixing separation property is obtained. Further, since the resin constituting the shell layer is a vinyl resin, high heat-resistant storage stability is obtained, and when the vinyl resin and the crystalline polyester resin are mixed at the time of heat fixing, the crystalline polyester resin is recrystallized. Therefore, it is possible to form an image in which occurrence of gloss unevenness is suppressed.

[Toner Production Method]
Examples of the method for producing the toner of the present invention include a wet production method prepared in an aqueous medium, such as an emulsion aggregation method.
The method for producing the toner of the present invention by the emulsion aggregation method includes, for example, 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 a coloring agent. An aqueous dispersion in which fine particles (hereinafter also referred to as “colorant fine particles”) are mixed is mixed, and the binder resin fine particles and the colorant fine particles are agglomerated and thermally fused to form toner particles. It is a manufacturing method.

The toner production method of the present invention is a method of producing an aqueous dispersion of resin fine particles containing a release agent and a vinyl resin by a miniemulsion polymerization method using a vinyl monomer and a release agent for forming the vinyl resin. A step of preparing.
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 a crystalline polyester resin (hereinafter also referred to as “crystalline polyester resin fine particles”) are dispersed in an aqueous medium;
(B) Resin fine particles containing a release agent and a vinyl resin (hereinafter, “release agent-containing resin fine particles”) by a miniemulsion polymerization method using a vinyl monomer and a release agent for forming a vinyl resin. A step of preparing an aqueous dispersion of
(C) a step of preparing an aqueous dispersion in which colorant fine particles are dispersed in an aqueous medium;
(D) a step of aggregating and fusing crystalline polyester resin fine particles and colorant fine particles in an aqueous medium to form core particles;
(E) a step of aggregating and fusing the release agent-containing resin fine particles 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) Step of preparing aqueous dispersion of crystalline polyester resin fine particles In this step, an aqueous dispersion of crystalline polyester resin fine particles of crystalline polyester resin is prepared.
The aqueous dispersion of crystalline polyester resin fine particles can be prepared by first synthesizing a crystalline polyester resin and dispersing the crystalline polyester resin in a fine particle form in an aqueous medium.
As a method for dispersing the crystalline polyester resin in the aqueous medium, an oil phase liquid is prepared by dissolving or dispersing the crystalline polyester resin in an organic solvent, and the oil phase liquid is dispersed in the aqueous medium by phase inversion emulsification or the like. And an organic solvent is removed after forming oil droplets in a state of being controlled to have a desired particle size.

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 the surfactant, conventionally known various anionic surfactants, cationic surfactants, nonionic surfactants and the like can be used.

  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 usage-amount of an organic solvent is 1-300 mass parts normally with respect to 100 mass parts of crystalline polyester resins, Preferably it is 1-100 mass parts, More preferably, it is 25-70 mass parts.

  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 crystalline polyester resin fine particles is preferably in the range of 50 to 500 nm in terms of volume-based median diameter.
The volume-based median diameter of the crystalline polyester resin fine particles is a value measured using “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.).

(B) Step of preparing aqueous dispersion of release agent-containing resin fine particles In this step, an aqueous dispersion of release agent-containing resin fine particles containing a release agent and a vinyl resin is prepared.
The aqueous dispersion of release agent-containing resin fine particles can be prepared by a miniemulsion polymerization method using a vinyl monomer and a release agent for obtaining a vinyl resin. Specifically, for example, a vinyl monomer and a release agent are added to an aqueous medium containing a surfactant, mechanical droplets are added to form droplets, and then a water-soluble radical polymerization initiator is used. The polymerization reaction proceeds in the droplets by the radicals. Note that an oil-soluble polymerization initiator may be contained in the droplet. Thereby, the aqueous dispersion of the release agent-containing resin fine particles containing the release agent and the vinyl resin can be prepared.

In the method for producing a toner of the present invention, a release agent is added in advance to a vinyl monomer solution for forming a vinyl resin, so that the release agent is added to the domain phase of the vinyl resin. Since it exists as a phase, it becomes easy to suppress the compatibility between the release agent and the crystalline polyester resin, and high fixing separation property is obtained.
The release agent is prepared separately in the shell layer by preparing an aqueous dispersion of release agent fine particles consisting only of the release agent and aggregating it with resin fine particles consisting only of the vinyl resin in the toner particle forming step. It can also be introduced.

The toner particles according to the present invention may contain other internal additives such as a charge control agent as necessary. For example, in this step, the internal additives are pre- It can be introduced into toner particles by adding it to a solution of a vinyl monomer for forming a 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 in the core particle forming step or the toner particle forming step, the internal additive fine particles are added together with other resin fine particles. It can also be introduced into toner particles by agglomeration.

  The release agent-containing resin fine particles may have a multilayer structure of two or more layers made of vinyl resins having different compositions, and the release agent-containing resin fine particles having such a structure have, for example, a two-layer structure. Prepares a dispersion of resin fine particles by emulsion polymerization treatment (first-stage polymerization) according to a conventional method, and a polymerization initiator and a vinyl monomer are added to the dispersion, and this system is polymerized (first treatment). (Two-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 (such as potassium persulfate and ammonium persulfate) 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, t-dodecyl mercaptan, and styrene dimers.

The average particle diameter of the release agent-containing resin fine particles is preferably in the range of 50 to 500 nm in terms of volume-based median diameter.
The volume-based median diameter of the release agent-containing resin fine particles is a value measured using “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.).

(C) Preparation Step of 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.).

(D) Core Particle Formation Step In this step, the crystalline polyester 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 more is added to an aqueous dispersion in which the above fine particles are dispersed in an aqueous medium, and the particles are aggregated and fused by heating.

  The fusing temperature is preferably 50 to 90 ° 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 2 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 Beckman Coulter, Inc.).

(E) Toner Particle Formation Step In this step, the release agent-containing resin fine particles are aggregated on the surface of the core particles and further fused by heating to form a shell layer to form toner particles.
Specifically, a coagulant having a critical coagulation concentration or more is added to an aqueous dispersion in which core particles and the fine particles are dispersed in an aqueous medium, and the mixture is heated and aggregated to be fused.

  The fusing temperature is preferably 70 to 95 ° C, for example.

  Examples of the flocculant that can be used in this step include the same ones as described above.

(F) Ripening step This step is performed as necessary, and in the maturing step, the toner particles obtained in the toner particle 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.

  According to the method for producing a toner of the present invention, the toner of the present invention can be easily produced by preparing a resin fine particle containing a release agent and a vinyl resin, which is produced by a miniemulsion polymerization method. Can do.

  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 resin fine particles, the colorant fine particles and the crystalline polyester resin fine particles, and the measurement of the molecular weight of the resin fine particles and the crystalline polyester resin were performed as described above.
Further, the measurement of the glass transition point of the resin fine particles and the toner and the measurement of the melting point of the crystalline polyester resin were performed as described above.
Furthermore, the carboxy group concentration or ester group concentration of each resin was calculated as described above.

[Toner Production Example 1]
(1) Preparation of aqueous dispersion [C1] of crystalline polyester resin fine particles (1-1) Synthesis of crystalline polyester resin In a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introducing device, Carboxylic acid: 220 parts by mass of dodecanedioic acid (molecular weight 230.3) and 174 parts by mass of polyhydric alcohol: 1,12-dodecanediol (molecular weight 202.33) were charged, and this system was stirred for 1 hour. The internal temperature was raised to 190 ° C. and it was confirmed that the mixture was uniformly stirred. Then, Ti (OBu) ₄ was added as a catalyst in an amount of 0.003% by mass based on the charged amount of the polyvalent carboxylic acid. In the amount of. 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 85 ° C. and a number average molecular weight (Mn) of 14,000.

(1-2) Preparation of Aqueous Dispersion of Crystalline Polyester Resin Fine Particles Crystalline polyester resin [C1] 30 parts by mass were melted and left in a melted state in an emulsifying disperser “Cavitron CD1010” (manufactured by Eurotech Co., Ltd.). On the other hand, it was transferred at a transfer rate of 100 parts by mass per minute. Simultaneously with the transfer of the crystalline polyester resin [C1] in the molten state, 70 mass parts of reagent ammonia water was diluted with ion-exchanged water in an aqueous solvent tank with respect to the emulsification disperser, and the concentration was 0.37 mass%. The diluted ammonia water 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 rotation speed of 60 Hz and a pressure of 5 kg / cm ² , an aqueous system of crystalline polyester resin fine particles having a volume-based median diameter of 200 nm and a solid content of 30 parts by mass. A dispersion [C1] was prepared.

(2) Preparation of aqueous dispersion [A1] of resin fine particles (first stage polymerization)
Into a 5 L reaction vessel equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introducing device, 8 g of sodium dodecyl sulfate was charged with 3 L of ion-exchanged water, and the internal temperature was 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. The temperature was raised to. After heating, 10 g of potassium persulfate dissolved in 200 g of ion-exchanged water was added, the liquid temperature was again 80 ° C., the following monomer mixture was added dropwise over 1 hour, and then heated at 80 ° C. for 2 hours. Then, polymerization was carried out by stirring to prepare a dispersion [a1] of resin fine particles.
Styrene 480g
n-Butyl acrylate 250g
Methacrylic acid 68.0g

(Second stage polymerization)
A 5 L reaction vessel equipped with a stirrer, temperature sensor, condenser, and nitrogen introducing device was charged with a solution of 7 g of polyoxyethylene (2) sodium dodecyl ether sulfate in 800 ml of ion-exchanged water and heated to 98 ° C. Then, 260 g of the resin fine particle dispersion [a1] and a solution obtained by dissolving the following monomer solution at 90 ° C. were added, and a mechanical disperser CLEARMIX having a circulation path (manufactured by M Technique Co., Ltd.) Thus, a dispersion containing emulsified particles (oil droplets) was prepared by mixing and dispersing for 1 hour.
Styrene (St) 284g
n-Butyl acrylate (BA) 92g
Methacrylic acid (MAA) 13g
n-octyl-3-mercaptopropionate 1.5 g
190g release agent (behenate behenate melting point 73 ° C)
Next, an initiator solution in which 6 g of potassium persulfate was dissolved in 200 ml of ion-exchanged water was added to this dispersion, and the system was heated and stirred at 84 ° C. for 1 hour to polymerize resin fine particles [a2 A dispersion was prepared.

(Third stage polymerization)
Furthermore, a solution prepared by dissolving 11 g of potassium persulfate in 400 ml of ion exchange water was added,
Styrene (St) 400g
n-Butyl acrylate (BA) 128g
Methacrylic acid (MAA) 28g
45 g of methyl methacrylate (MMA)
n-Octyl-3-mercaptopropionate 8g
A monomer mixture consisting of was added dropwise over 1 hour. After completion of the dropwise addition, polymerization was carried out by heating and stirring for 2 hours, followed by cooling to 28 ° C. to prepare an aqueous dispersion [A1] of resin fine particles.
With respect to the obtained aqueous dispersion [A1] of resin fine particles, the average particle size of the resin fine particles is 220 nm in terms of volume-based median diameter, the glass transition point (Tg) is 55 ° C., and the weight average molecular weight (Mw) is 32,000. Met.

(3) Preparation of aqueous dispersion of colorant fine particles [Bk] 90 parts by mass of sodium dodecyl sulfate was added to 1600 parts by mass of ion-exchanged water. While stirring this solution, 420 parts by mass of carbon black (Regal 330R: manufactured by Cabot) is gradually added, and then dispersed using a stirring device “CLEARMIX” (manufactured by M Technique Co., Ltd.). Thus, an aqueous dispersion [Bk] of fine colorant particles was prepared.
With respect to the obtained aqueous dispersion [Bk], the average particle diameter (volume-based median diameter) of the colorant fine particles was 110 nm.

(4) Formation of toner particles [1] An aqueous dispersion [C1] in which 720 parts by mass of crystalline polyester resin fine particles are dispersed in a zebra flask equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device, and ions After charging 2500 parts by weight of exchange water and 500 parts by weight of an aqueous dispersion of fine colorant particles [Bk] and adjusting the liquid temperature to 25 ° C., a sodium hydroxide aqueous solution with a concentration of 25% by weight was added to adjust the pH to 10. It was adjusted.
Next, an aqueous solution in which 54.3 parts by mass of magnesium chloride hexahydrate is dissolved in 54.3 parts by mass of ion-exchanged water is added, and then the temperature of the system is raised to 97 ° C. to thereby form polyester resin fine particles. And agglomeration reaction between the colorant fine particles.
After the start of this agglomeration reaction, sampling is performed periodically, and the volume-based median diameter of the core particles is measured using a particle size distribution analyzer “Coulter Multisizer 3” (manufactured by Beckman Coulter). Aggregation was continued while stirring was continued until 6.3 μm. Thereafter, an aqueous dispersion [A1] in which 180 parts by mass of resin fine particles were dispersed was added and agglomerated for 60 minutes while continuing stirring.
Thereafter, an aqueous solution in which 23.0 parts by mass of sodium chloride was dissolved in 92 parts by mass of ion-exchanged water was added, the temperature of the system was kept at 95 ° C., and stirring was continued for 4 hours, and a flow-type particle image analyzer “FPIA-2100” When the circularity reached 0.946 as measured by (Sysmex), the reaction was stopped by cooling to 30 ° C. under conditions of 6 ° C./min to obtain a dispersion of toner particles. The toner particles after cooling had a particle size of 6.1 μm and a circularity of 0.946.
The toner particle dispersion thus obtained was subjected to solid-liquid separation using a basket-type centrifuge “MARK III Model No. 60 × 40” (manufactured by Matsumoto Kikai Co., Ltd.) to form a wet cake. This wet cake was repeatedly washed and solid-liquid separated with the basket-type centrifuge until the electric conductivity of the filtrate reached 15 μS / cm. Thereafter, a “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.) was used, and the temperature was 40 The toner particles [1] were obtained by spraying a stream of air at a temperature of 20 ° C. and a humidity of 20% RH until the water content was 0.5 mass% and cooling to 24 ° C.
1% by mass of hydrophobic silica particles and 1.2% by mass of hydrophobic titanium oxide were added to the obtained toner particles [1], and the peripheral speed of the rotor blades was 24 m / s using a Henschel mixer. Then, the mixture was mixed for 20 minutes and passed through a 400-mesh sieve to add an external additive to obtain toner [1].
In toner [1], the shape and particle size of the toner particles did not change with the addition of the external additive.

[Toner Production Examples 2 to 14]
Toners [2] to [14] 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, an aqueous dispersion [C2] of crystalline polyester resin fine particles was used except that (1-1) crystalline polyester resin synthesis in Toner Production Example 1 was modified according to Table 2. It was obtained in the same manner.
Further, in Table 1, resin fine particle aqueous dispersions [A2] to [A4] represent monomer prescriptions in the preparation of (2) resin fine particle aqueous dispersion [A1] in Toner Production Example 1. Other than changing according to 3, it was obtained in the same manner. The aqueous dispersion of resin fine particles [A4] is one in which no release agent is added in the second stage polymerization. The toner [10] using the aqueous dispersion [A4] is prepared by separately preparing an aqueous dispersion of release agent fine particles consisting only of a release agent (behenate behenate melting point 73 ° C.), and (4) toner particles. In the formation, the aqueous dispersion of resin fine particles [A4] and the aqueous dispersion of the release agent fine particles were added in an amount of 30 parts by mass in terms of solid content. Also for toner [11], an aqueous dispersion of release agent fine particles consisting only of a release agent (behenate behenate melting point 73 ° C.) was separately prepared. (4) In forming toner particles, a crystalline polyester resin was prepared. It is obtained by adding 30 parts by mass of the aqueous dispersion of the releasing agent fine particles together with the fine particle aqueous dispersion [C1] in terms of solid content.
Further, in Table 1, the aqueous dispersion [X] shown in the column of other resins is an aqueous dispersion [X] of styrene-acryl-modified polyester resin fine particles prepared by the following preparation examples.

[Preparation of aqueous dispersion [X] of fine particles of styrene-acryl-modified polyester resin]
In a 10-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, 500 parts by mass of bisphenol A propylene oxide 2 mol adduct, 117 parts by mass of terephthalic acid, 82 parts by mass of fumaric acid, ester 2 parts by mass of a catalyst for oxidation (tin octylate) was subjected to a polycondensation reaction at 230 ° C. for 8 hours, further reacted at 8 kPa for 1 hour, cooled to 160 ° C., 10 parts by mass of acrylic acid, 30 parts by mass of styrene, A mixture of 7 parts by weight of butyl acrylate and 10 parts by weight of a polymerization initiator (di-t-butyl peroxide) was dropped with a dropping funnel over 1 hour, and after the addition, the addition polymerization reaction was continued for 1 hour while maintaining at 160 ° C. Then, the temperature is raised to 200 ° C. and held at 10 kPa for 1 hour, and then acrylic acid, styrene, and butyl acrylate are removed. Ri, styrene - obtain an acrylic-modified polyester resin (X).
100 parts by mass of the obtained styrene-acryl-modified polyester resin [X] was added to 400 parts by mass of ethyl acetate (manufactured by Kanto Chemical Co., Inc.) with stirring and dissolved by heating. Subsequently, 638 parts by mass of a sodium lauryl sulfate solution having a concentration of 0.26% by mass prepared in advance was mixed, and the mixture was stirred and ultrasonicated with an ultrasonic homogenizer “US-150T” (manufactured by Nihon Seiki Seisakusho) at 300 μA for 30 minutes. After dispersion, using a diaphragm vacuum pump “V-700” (manufactured by BUCHI) while being heated to 50 ° C., ethyl acetate was completely removed while stirring for 5 hours under reduced pressure, and the average particle size ( An aqueous dispersion [X] of styrene-acryl-modified polyester resin fine particles having a volume-based median diameter (D ₅₀ ) of 140 nm and a solid content of 13.5% by mass was obtained.

[Developer Production Examples 1 to 14]
To each of the toners [1] to [14], 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. Thus, developers [1] to [14] were produced.

[Examples 1 to 10, Comparative Examples 1 to 4]
(1) Evaluation of low-temperature fixability In the copying machine “bizhub PRO C6550” (manufactured by Konica Minolta Business Technologies), the fixing device can be changed within the range of 120 to 200 ° C. in the surface temperature (fixing temperature) of the heating roller. A fixing experiment was conducted to fix a solid image with a toner adhesion amount of 8 mg / cm ² on a high-quality paper of A4 size in an environment of normal temperature and humidity (temperature of 20 ° C., humidity of 50% RH) using a modified one. The fixing temperature was repeatedly increased from 120 ° C. to 200 ° C. while being changed in steps 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 4. In addition, it is judged that the lower limit fixing temperature is 140 ° C. or lower.

(2) Evaluation of fixing separation property Using modified “bizhub C6500” (manufactured by Konica Minolta Business Technologies Co., Ltd.), 85 g / f m ² T (Oji Paper Co., Ltd.) tip margin 5 mm, fixing temperature is set to 195 ° C for upper heating / pressing member and 120 ° C for lower heating / pressing member. The amount of adhesion (g / m ² ) of the solid image immediately before the occurrence of a paper jam (jam) was measured, and this was used as a separation limit adhesion amount as a measure of fixing separation performance. The larger this value, the better the separation performance, and 1.0 g / m ² or more is acceptable. In addition, it implements in normal temperature normal humidity environment (NN environment: 25 degreeC, 50% RH).

(3) Evaluation of heat-resistant storage stability After taking 0.5 g of toner into a 10 ml glass bottle with an inner diameter of 21 mm, the lid is closed, and after shaking 600 times at room temperature with a tap denser “KYT-2000” (manufactured by Seishin Enterprise), the lid is removed. In this state, the sample was left in an environment of a temperature of 57.5 ° C. and a humidity of 35% RH for 2 hours. Next, place the toner on a 48-mesh (mesh 350 μm) sieve, taking care not to crush the toner aggregates, set the powder tester (manufactured by Hosokawa Micron), and fix it with a press bar and knob nut. After adjusting the vibration strength to a feed width of 1 mm and applying vibration for 10 seconds, the ratio (mass%) of the amount of toner remaining on the sieve was measured. The toner aggregation rate is a value calculated by the following equation (3). A toner aggregation rate of 15% by mass is accepted.
Formula (3): toner aggregation rate (%) = residual toner mass on sieve (g) /0.5 (g) × 100

(4) Evaluation of gloss unevenness A solid pattern with a black toner having a toner adhesion amount of 6.0 ± 0.5 g / m ² was drawn, and the state of gloss unevenness was visually evaluated. The adhesion amount of the image to be measured was 12.0 ± 0.5 mg, and CF paper (manufactured by Konica Minolta Business Technologies) was used as the transfer material. The gloss unevenness was evaluated according to the criteria described below. △ More than pass.
○: The difference between the maximum glossiness and the minimum glossiness is hardly known. That have practical problems

Claims (4)

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 particles contain a crystalline polyester resin,
The shell layer contains a vinyl resin and a release agent,
A toner for developing an electrostatic charge image, wherein a mass ratio of the crystalline polyester resin to the vinyl resin is 95: 5 to 60:40. The ester group concentration of the crystalline polyester resin is 0.1 to 7.5 mmol / g,
2. The electrostatic image developing toner according to claim 1, wherein the vinyl resin has a carboxy group concentration of 0.2 to 1.0 mmol / g.   The electrostatic charge image developing toner according to claim 1, wherein a content ratio of the releasing agent in the toner particles is 0.5 to 5% by mass. A method for producing the electrostatic image developing toner according to any one of claims 1 to 3,
It has a step of preparing an aqueous dispersion of resin fine particles containing a release agent and a vinyl resin by a miniemulsion polymerization method using a vinyl monomer and a release agent for forming the vinyl resin. A method for producing a toner for developing an electrostatic charge image.