JP6083326B2 - Toner for electrostatic image development - Google Patents

Description

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

In recent years, as a toner for developing an electrostatic image (hereinafter, also simply referred to as “toner”), a low-temperature fixing toner having a low fixing temperature that can be melted at a low temperature is required from the viewpoint of reducing the environmental load.
In order to lower the fixing temperature of the toner, it is necessary to use a binder resin having a low melting temperature and melt viscosity. However, generally, the low-temperature fixing of the toner has a trade-off relationship with respect to the heat-resistant storage property, and it is a problem to achieve both.

In order to achieve both low-temperature fixability and heat-resistant storage stability, a toner having a core-shell structure in which a shell layer is provided on the surface of the core particles has been designed. For example, Patent Document 1 discloses a toner that achieves both low-temperature fixability and heat-resistant storage stability by using a polyester resin that is advantageous for low-temperature fixing for core particles and a vinyl resin for a shell layer. .
However, since the affinity between the polyester resin and the vinyl resin is poor, it is difficult to form a uniform shell layer.

In order to solve such a problem, a toner using a styrene-acryl-modified polyester resin has been proposed for the purpose of improving the affinity between the core particles and the shell layer.
For example, in Patent Document 2, a styrene-acrylic copolymer resin having a low glass transition point and a low weight average molecular weight is used for the core particles, and a styrene-acrylic modified polyester resin having a high glass transition point is used for the shell layer. The toner used is disclosed.
For example, Patent Document 3 discloses a toner in which a styrene-acrylic copolymer resin and a styrene-acrylic modified polyester resin are used for the core particles, and a styrene-acrylic modified polyester resin is used for the shell layer. .

However, the toner disclosed in Patent Document 2 is designed to lower the melt viscosity of the entire core particle in order to achieve low-temperature fixing. With such a toner, the resulting image has a high gloss. In the character image, there is a problem that the character is difficult to read due to glare.
On the other hand, in the toner disclosed in Patent Document 3, when the styrene-acrylic copolymer resin constituting the core particles and the polyester polymer segment constituting the styrene-acrylic modified polyester resin are incompatible, styrene -As a result of localization of the polyester polymer segment in the acrylic copolymer resin, the entire resin of the core particles cannot be softened uniformly, and therefore the desired low-temperature fixability cannot be obtained satisfactorily. There was a problem.
As described above, it is difficult to achieve both low temperature fixability and low gloss properties (low gloss) while maintaining the heat-resistant storage stability by obtaining the affinity between the core particles and the shell layer. there were.

JP 2008-287256 A JP 2012-247659 A JP 2013-33233 A

  The present invention has been made in consideration of the above-mentioned circumstances, and the object thereof is to obtain heat-resistant storage stability and to form a low-gloss image while obtaining low-temperature fixability. An object is to provide a toner for developing an electrostatic image.

The toner for developing an electrostatic charge image of the present invention comprises a core particle made of a vinyl resin and an amorphous polyester resin compatible with the vinyl resin, and a vinyl polymer segment and a polyester polymer segment that cover the core particle are bonded to each other. Consisting of a core-shell toner particle comprising a shell layer of an amorphous resin,
The vinyl resin constituting the core particle has a weight average molecular weight (Mw) calculated from a molecular weight distribution measured by gel permeation chromatography (GPC) of 20,000 to 60,000, and the molecular weight distribution In which the ratio of the resin component having a molecular weight of 100,000 or more is 3 to 13 area%,
The glass transition point of the amorphous polyester resin constituting the core particles is 35 to 50 ° C., and the content of the amorphous polyester resin in the total amount of the resin constituting the toner particles is 5 to 30% by mass. Yes,
The glass transition point of the amorphous resin constituting the shell layer is 55 to 65 ° C.

  In the toner for developing an electrostatic charge image of the present invention, the weight average molecular weight (Mw) calculated from the molecular weight distribution measured by gel permeation chromatography (GPC) of the amorphous polyester resin constituting the core particle is 7. , 20,000 to 20,000 is preferable.

  In the electrostatic image developing toner of the present invention, the content of the vinyl polymer segment in the amorphous resin constituting the shell layer is preferably 5 to 30% by mass.

  According to the toner for developing an electrostatic charge image of the present invention, a core particle comprising a vinyl resin containing a high molecular weight component and an amorphous polyester resin having a low glass transition point is compatible with the core particle. Since it has a core-shell structure composed of a shell layer made of a vinyl-modified polyester resin, heat-resistant storage stability can be obtained, and furthermore, a low-gloss image can be formed while obtaining low-temperature fixability.

  Hereinafter, the present invention will be specifically described.

The toner of the present invention includes an amorphous resin formed by bonding a vinyl resin and a core particle made of an amorphous polyester resin compatible with the vinyl resin, and a vinyl polymer segment and a polyester polymer segment covering the core particle. (Hereinafter, also referred to as “vinyl-modified polyester resin”) consisting of toner particles having a core-shell structure composed of a shell layer.
Specifically, the vinyl resin constituting the core particle has a weight average molecular weight (Mw) calculated from a molecular weight distribution measured by gel permeation chromatography (GPC) of 20,000 to 60,000, and In the chromatogram showing the molecular weight distribution, the ratio of the resin component (high molecular weight component) having a molecular weight of 100,000 or more is 3 to 13% by area, and the glass transition of the amorphous polyester resin constituting the core particle The glass transition of the vinyl-modified polyester resin having a point of 35 to 50 ° C., and further containing 5 to 30% by mass of the amorphous polyester resin in the total amount of the resin constituting the toner particles. A point is 55-65 degreeC, It is characterized by the above-mentioned.

According to the toner as described above, a core particle formed by mixing a vinyl resin containing a high molecular weight component and an amorphous polyester resin having a low glass transition point, and a vinyl-modified polyester resin covering the core particle. Since it has a core-shell structure composed of a shell layer, heat-resistant storage stability is obtained, low-temperature fixability is obtained, and a low-gloss image can be formed.
The reason is considered as follows. In other words, the amorphous polyester resin has a low glass transition point in the core particle, and the amorphous polyester resin and the vinyl resin are present in a mutually compatible state, so that the entire core particle is It can be uniformly softened, thereby achieving low temperature fixability. Further, since the vinyl resin constituting the core particle has a specific amount of a high molecular weight component, a low gloss image can be formed without impairing the low-temperature fixability. In addition, since the two types of resins constituting the core particles are in a compatible state, the dispersibility of the colorant in the core particles becomes high, and as a result, a uniform image without gloss unevenness can be formed. In addition, since the shell layer is formed of the vinyl-modified polyester resin, the affinity with the core particles is improved, and the vinyl-modified polyester resin is composed of the vinyl resin and the amorphous polyester resin that constitute the core particles. Since the compatibility is low, the heat-resistant storage property can be secured without hindering the effect of the core particles.
Accordingly, the toner particles as a whole can have heat-resistant storage stability and can form a low gloss image while obtaining low-temperature fixability.

[Core particles]
The core particles constituting the toner particles according to the present invention contain a vinyl resin and an amorphous polyester resin compatible with the vinyl resin, and the vinyl resin and the amorphous polyester resin are compatible with each other. It is said that.
Specifically, the vinyl resin and the amorphous polyester resin constituting the core particle have a difference (ΔSP) in solubility parameter value (SP value) of 0.3 or less.
When the difference in SP value (ΔSP) between the vinyl resin and the amorphous polyester resin constituting the core particle exceeds 0.3, it was difficult to form toner particles, and toner particles could be formed. However, the desired low-temperature fixability cannot be obtained.

In the present invention, the SP value is a solubility parameter value at 25 ° C., which is a value inherent to the substance, and is one useful measure for predicting the solubility of the substance. The SP value indicates that the polarity is higher as the numerical value is larger, and the polarity is lower as the numerical value is smaller. And when mixing 2 types of substances, so that the difference of both SP value is small, so that solubility becomes large.
The SP value of the resin is calculated as the product of the SP value and the molar ratio of each monomer forming the resin. For example, assuming that the resin is formed from two types of monomers, X and Y, the mass ratio of each monomer is x, y (mass%), the molecular weight is Mx, My, and the SP value is SPx. , SPy, the SP value of this resin is represented by the following formula (1).
Formula (1): SP = {(x * SPx / Mx) + (y * SPy / My)} * {1 / (x / Mx + y / My)}
The SP value of a monomer is determined from the evaporation energy (Δ _ei ) from “Polym. Eng. Sci. Vol 14. p114 (1974)” proposed by Fedors for atoms or atomic groups in the molecular structure of the monomer. ) And molar volume (Δ _vi ) are calculated and calculated from the following formula (2). However, for a double bond that is cleaved during polymerization, the cleaved state is taken as its molecular structure.
Formula (2): σ = (ΣΔ _ei / ΣΔ _vi ) ^1/2
When the SP value of the monomer cannot be calculated by the above formula (2), as a specific value, documents such as the Polymer Handbook (published by Wiley) 4th edition or the independent administrative agency “Materials and Materials Research Organization” Please refer to the item of solubility parameter (http://polymer.nims.go.jp/guide/guide/p5110.html) described in the database “PolyInfo” (http://polymer.nims.go.jp). Can do.

[Vinyl resin constituting core particles]
The vinyl resin constituting the core particle has a weight average molecular weight (Mw) calculated from a molecular weight distribution measured by gel permeation chromatography (GPC) of 20,000 to 60,000, preferably 35,000 to 50, In the chromatogram showing the molecular weight distribution, the ratio of the resin component having a molecular weight of 100,000 or more is 3 to 13 area%, preferably 5 to 8 area%.

  When the weight average molecular weight (Mw) of the vinyl resin is 20,000 or more, the desired heat-resistant storage stability is ensured without the compatibility between the vinyl resin and the vinyl-modified polyester resin constituting the shell layer. can get. Further, when the weight average molecular weight (Mw) of the vinyl resin is 60,000 or less, sufficient low-temperature fixability can be obtained.

  Further, when the ratio of the resin component having a molecular weight of 100,000 or more is 3 area% or more, a low-gloss image can be reliably formed. Further, when the ratio of the resin component having a molecular weight of 100,000 or more is 13 area% or less, the desired low-temperature fixability can be obtained.

Measurement of molecular weight distribution by GPC was performed as follows. That is, using an apparatus “HLC-8220” (manufactured by Tosoh Corporation) and a column “TSKguardcolumn + TSKgelSuperHZM-M3 series” (manufactured by Tosoh Corporation), while maintaining the column temperature at 40 ° C., tetrahydrofuran (THF) was used as a carrier solvent at a flow rate of 0. The sample to be measured was poured at a rate of 2 ml / min, dissolved in tetrahydrofuran to a concentration of 1 mg / ml under a dissolution condition in which the measurement sample (vinyl resin) was treated for 5 minutes using an ultrasonic disperser at room temperature, and then the pore size was 0.2 μm. A sample solution is obtained by processing with a membrane filter, and 10 μL of this sample solution is injected into the apparatus together with the carrier solvent described above, detected using a refractive index detector (RI detector), and the molecular weight distribution of the measurement sample is simply determined. Using a calibration curve measured using dispersed polystyrene standard particles calculate. As a standard polystyrene sample for calibration curve measurement, molecular weights manufactured by Pressure Chemical Co., Ltd. are 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1 .1 × 10 ⁵ , 3.9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ , and at least about 10 standard polystyrene samples were measured, and a calibration curve It was created. A refractive index detector was used as the detector.

  The ratio of the high molecular weight component is such that the molecular weight is 10 when the area of the peak derived from the vinyl-modified polyester resin soluble in THF is 100% by area in the chromatogram showing the molecular weight distribution measured by GPC as described above. The area ratio of more than 10,000 resin components.

  The vinyl resin is formed using a monomer having a vinyl group (hereinafter referred to as “vinyl monomer”). As the vinyl resin, a styrene-acrylic copolymer resin, a styrene resin, an acrylic resin is used. Examples of the resin include styrene-acrylic copolymer resins.

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, it is preferable to use a monomer having a carboxy group as the vinyl monomer, and the proportion of the monomer having a carboxy group in all vinyl monomers is 2 to 7% by mass. It is preferable. When the proportion of the monomer having a carboxy group is excessive, the amount of moisture adsorbed on the surface of the toner particles increases, which may cause generation of toner blisters and expansion of the difference in charge amount environment.

  Furthermore, polyfunctional vinyls can be used as the vinyl monomer, and the vinyl polymer 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.

[Softening point of vinyl resin constituting core particle]
The softening point of the vinyl resin is preferably 80 to 110 ° C, more preferably 90 to 105 ° C.
When the softening point is 80 ° C. or higher, fixing separation property can be obtained with certainty. On the other hand, when the softening point is 110 ° C. or lower, sufficient low-temperature fixability can be obtained.

The softening point 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 starting temperature of 60 ° C., a preheating time of 300 seconds, and a heating rate of 6 ° C./min. from (1mm diameter × 1 mm), extruded from the time of preheating ends with piston diameter 1 cm, offset method temperature was measured by setting the offset value 5mm at a melt temperature measuring method of the temperature ramps T _{Offse t} is the softening point.

[Amorphous polyester resin constituting the core particles]
The amorphous polyester resin constituting the core particle is obtained by polycondensation reaction using polyvalent carboxylic acid monomer (derivative) and polyhydric alcohol monomer (derivative) as raw materials, and does not have a clear melting point. Say things.

  In the present invention, the amorphous polyester resin refers to a polyester resin in which no clear endothermic peak is observed in differential scanning calorimetry (DSC). 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.

  As polyvalent carboxylic acid monomer derivatives, alkyl esters, acid anhydrides and acid chlorides of polyvalent carboxylic acid monomers can be used. As polyhydric alcohol monomer derivatives, ester compounds of polyhydric alcohol monomers and hydroxycarboxylic acids are used. Can be used.

  Examples of the polyvalent carboxylic acid monomer include oxalic acid, succinic acid, maleic acid, mesaconic acid, adipic acid, β-methyladipic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, and dodecanedicarboxylic acid. Acid, fumaric acid, citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, malic acid, citric acid, hexahydroterephthalic acid, malonic acid, pimelic acid, tartaric acid, mucoic acid, Phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediglycolic acid, p-phenylenediglycolic acid, o-phenylenediglycol Glycolic acid, diphenylacetic acid, diphenyl divalent carboxylic acids such as p, p'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracene dicarboxylic acid, dodecenyl succinic acid; Examples thereof include divalent or higher carboxylic acids such as merit acid, pyromellitic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, and pyrenetetracarboxylic acid.

  Examples of the polyhydric alcohol monomer include ethylene glycol, propylene glycol, butanediol, diethylene glycol, hexanediol, cyclohexanediol, octanediol, decanediol, dodecanediol, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, and the like. And trivalent or higher polyols such as glycerin, pentaerythritol, hexamethylol melamine, hexaethylol melamine, tetramethylol benzoguanamine, and tetraethylol benzoguanamine.

  The ratio of the polyhydric carboxylic acid monomer to the polyhydric alcohol monomer is preferably an equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] of the polyhydric alcohol monomer and the carboxy group [COOH] of the polyhydric carboxylic acid. Is 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2.

The method for producing the amorphous polyester resin is not particularly limited, and can be produced by using a general polyester polymerization method in which a polycarboxylic acid monomer and a polyhydric alcohol monomer are reacted under a catalyst. The direct polycondensation or the transesterification method is preferably used in accordance with the type of monomer.
Various conventionally known catalysts can be used as the catalyst for synthesizing the amorphous polyester resin.

[Glass transition point of amorphous polyester resin constituting core particles]
The glass transition point of the amorphous polyester resin is 35 to 50 ° C, preferably 40 to 45 ° C.
When the glass transition point of the amorphous polyester resin is 35 ° C. or higher, the desired heat-resistant storage stability is obtained. On the other hand, when the glass transition point of the amorphous polyester resin is 50 ° C. or lower, the desired low-temperature fixability can be obtained.

The glass transition point (Tg) of the amorphous polyester resin is a value measured using “Diamond DSC” (manufactured by PerkinElmer).
As a measurement procedure, 3.0 mg of a measurement sample (amorphous polyester 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.

[Molecular weight of amorphous polyester resin constituting core particles]
The weight average molecular weight (Mw) calculated from the molecular weight distribution measured by GPC of the amorphous polyester resin is preferably 7,000 to 20,000, more preferably 8,000 to 12,000. .
When the amorphous polyester resin has a weight average molecular weight (Mw) of 7,000 or more, sufficient heat-resistant storage stability can be reliably obtained. On the other hand, when the weight average molecular weight (Mw) is 20,000 or less, sufficient low-temperature fixability can be reliably obtained.

  The molecular weight distribution measurement by GPC of the amorphous polyester resin is performed in the same manner as described above except that the amorphous polyester resin is used as a measurement sample.

[Content ratio of amorphous polyester resin constituting core particles]
The total amount of the resin constituting the toner particles, that is, the content ratio of the amorphous polyester resin to the binder resin is 5 to 30% by mass, and preferably 10 to 20% by mass.
When the content of the amorphous polyester resin is 5% by mass or more, the desired low-temperature fixability can be obtained. On the other hand, when the content of the amorphous polyester resin is 30% by mass or less, a low-gloss image can be formed.

[Shell layer]
The shell layer constituting the toner particles according to the present invention contains an amorphous resin (vinyl-modified polyester resin) formed by bonding a vinyl polymer segment and a polyester polymer segment, and may contain other resins. .
This shell layer preferably has a structure in which the core particles are completely covered. By having such a structure, heat-resistant storage property can be obtained reliably.
The vinyl-modified polyester resin constituting the shell layer has low compatibility with both the vinyl resin constituting the core particle and the amorphous polyester resin.

  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 polymerizable monomers such as styrene, pn-dodecylstyrene, 2,4-dimethylstyrene, 3,4-dichlorostyrene, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate Cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, methacrylate Acrylic polymerization such as butyl methacrylate, butyl methacrylate, 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 above-described vinyl resin can be used. Moreover, said vinyl monomer can be used individually by 1 type or in combination of 2 or more types.

  The polyester polymerized segment is an amorphous one formed by a polyvalent carboxylic acid and a polyhydric alcohol and does not show a clear endothermic peak in DSC measurement.

  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.

As the polyvalent carboxylic acid, an aliphatic unsaturated dicarboxylic acid is preferably used. The aliphatic unsaturated dicarboxylic acid refers to a chain dicarboxylic acid having a vinylene group in the molecule.
By using such an aliphatic unsaturated dicarboxylic acid, it is possible to reliably form a smooth shell layer with a more uniform film thickness while being a thin layer.
The proportion of the aliphatic unsaturated dicarboxylic acid in the total polyvalent carboxylic acid used is preferably 25 to 75 mol%, more preferably 30 to 60 mol%.
When the ratio of the aliphatic unsaturated dicarboxylic acid is within the above range, a smooth shell layer having a more uniform film thickness can be more reliably formed even though it is a thin layer.
When the proportion of the aliphatic unsaturated dicarboxylic acid is too small, a smooth shell layer with a more uniform film thickness is not formed even though it is a thin layer, and sufficient heat storage stability and chargeability may not be obtained. is there. On the other hand, when the proportion of the aliphatic unsaturated dicarboxylic acid is excessive, there is a possibility that sufficient chargeability cannot be obtained.

  Examples of the polyhydric alcohol include, for example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1, 8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1, Aliphatic diols such as 18-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 thereof; Glycerin, pentaeryth Tall, hexamethylol melamine, can be cited hexa ethyl melamine, tetramethylol benzoguanamine, etc. trihydric or higher polyols, such as tetra-ethyl benzoguanamine the.

The content of the vinyl polymerization segment in the vinyl-modified polyester resin is preferably 5 to 30% by mass, more preferably 15 to 25% by mass.
Specifically, the content of the vinyl polymerization segment is determined based on the total mass of the resin material used for synthesizing the vinyl-modified polyester resin, that is, the polyvalent carboxylic acid and polyhydric alcohol serving as the polyester polymerization segment, and the vinyl polymerization segment. Is a ratio of the mass of the vinyl monomer to the total mass of the total of the vinyl monomer to be combined with the both reactive monomers for bonding them.
When the content ratio of the vinyl polymerized segment is 5% by mass or more, the adhesion between the shell layer made of the vinyl-modified polyester resin and the core particles made of the vinyl resin and the amorphous polyester resin can be improved, and the mechanical properties are high. Strength is obtained. On the other hand, since it is 30% by mass or less, compatibility with the polyester polymerization segment can be suppressed to a very low level, and the glass transition point of the site due to the polyester polymerization segment can be suppressed from decreasing. A heat-resistant storage property is obtained.

[Glass transition point of vinyl-modified polyester resin constituting shell layer]
The glass transition point of the vinyl-modified polyester resin is 55 to 65 ° C, preferably 60 to 65 ° C.
When the glass transition point of the vinyl-modified polyester resin constituting the shell layer is 55 ° C. or higher, the obtained toner has high thermal strength and sufficient heat-resistant storage stability is obtained. On the other hand, when the glass transition point is 65 ° C. or lower, sufficient low-temperature fixability can be obtained.

  The glass transition point of the vinyl-modified polyester resin is a value measured in the same manner as described above except that the vinyl-modified polyester resin is used as a measurement sample.

[Molecular weight of vinyl-modified polyester resin constituting the shell layer]
The weight average molecular weight (Mw) calculated from the molecular weight distribution measured by GPC of the vinyl-modified polyester resin is preferably 15,000 to 30,000.
When the weight average molecular weight (Mw) of the vinyl-modified polyester resin is 15,000 or more, heat-resistant storage stability can be reliably obtained. On the other hand, when the weight average molecular weight (Mw) is 30,000 or less, deterioration of the low-temperature fixability can be reliably suppressed.

  The molecular weight distribution measurement by GPC of the vinyl-modified polyester resin is performed in the same manner as described above except that the vinyl-modified polyester resin is used as a measurement sample.

The softening point of the vinyl-modified polyester resin is preferably 80 to 110 ° C, more preferably 90 to 105 ° C.
The softening point of the vinyl-modified polyester resin is a value measured in the same manner as described above except that the vinyl-modified polyester resin is used as a measurement sample.

[Content ratio of vinyl-modified polyester resin constituting the shell layer]
The total amount of the resin constituting the toner particles, that is, the content ratio of the vinyl-modified polyester resin to the binder resin is 5 to 30% by mass, preferably 5 to 10% by mass.
When the content ratio of the vinyl-modified polyester resin is 5% by mass or more, the shell layer can be formed on the surface of the core particles with high uniformity, and the desired heat-resistant storage stability can be reliably obtained. On the other hand, when the content is 30% by mass or less, a low-gloss image can be reliably formed.

[Method for producing vinyl-modified polyester resin constituting shell layer]
The vinyl-modified polyester resin can be produced by bonding an amorphous polyester polymer segment and a vinyl polymer segment via both reactive monomers. Specifically, it may be produced by performing a polycondensation reaction in the presence of a polyvalent carboxylic acid / polyhydric alcohol at least at any time before, during and after the step of addition polymerization of the vinyl monomer. it can.
Specifically, an existing general scheme can be used. 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 a crystalline polyester polymerization segment is necessary. Depending on the method, a trivalent or higher valent vinyl monomer serving as a cross-linking agent is added to the reaction system to further advance the polycondensation reaction.
(2) After performing a polycondensation reaction of polyvalent carboxylic acid and polyhydric alcohol to form a crystalline polyester polymer segment, an addition polymerization reaction of a vinyl monomer to form a vinyl polymer segment is performed, and then A method in which 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 for forming a crystalline polyester polymerization segment After the condensation polymerization reaction of alcohol is performed in parallel and the addition polymerization reaction is completed, a trivalent or higher valent vinyl monomer as a cross-linking agent is added to the reaction system as necessary, and the temperature conditions are suitable for the condensation polymerization reaction. A method for further proceeding the condensation polymerization reaction under.

  Both reactive monomers are added together with polyvalent carboxylic acid / polyhydric alcohol and / or vinyl monomer.

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 (C1-3) esters may be used. From this viewpoint, it is preferable to use acrylic acid, methacrylic acid and fumaric acid.
In addition, it is preferable to use a monovalent vinyl carboxylic acid as a bi-reactive monomer rather than a polyvalent vinyl carboxylic acid from the viewpoint of toner durability. This is probably because the reactivity between the monovalent vinyl-based carboxylic acid and the vinyl monomer is high, so that it can be easily hybridized. On the other hand, when a dicarboxylic acid such as fumaric acid is used as the bireactive monomer, the durability of the toner is slightly inferior. This is presumably because the reactivity between the dicarboxylic acid and the vinyl monomer is low and it is difficult to form a uniform hybrid, so that it takes a domain structure.

  The amount of the both reactive monomers used is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the total amount of vinyl monomers from the viewpoint of improving the low temperature fixability, high temperature offset resistance and durability of the toner. -8 parts by mass is more preferable, 0.3-8 parts by mass is preferable, and 0.5-5 parts by mass is more preferable with respect to 100 parts by mass of the total amount of the polyvalent carboxylic acid and the polyhydric alcohol.

  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., and 140 to 180. ° 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 compounds, and tin octylate. These may be used alone or in combination. it can.

  The toner particles may contain other resins as the binder resin in addition to the above-described vinyl resin, amorphous polyester resin, and vinyl-modified polyester resin.

[Configuration of toner particles]
In addition to the binder resin, the toner particles according to the present invention may contain an internal additive such as a colorant, a release agent, and a charge control agent, if necessary.
Each of the colorant, the release agent, and the charge control agent may be contained in the core particle, may be contained in the shell layer, or may be contained in both, but the colorant is contained in the core particle. It is preferably contained.

[Colorant]
As the colorant, generally known dyes and pigments can be used.
As a colorant for obtaining a black toner, various known materials such as carbon black such as furnace black and channel black, magnetic materials such as magnetite and ferrite, dyes, and inorganic pigments containing nonmagnetic iron oxide are arbitrarily selected. Can be used.
As the colorant for obtaining a color toner, known ones such as dyes and organic pigments can be arbitrarily used. Specifically, examples of the organic pigment include C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 81: 4, 122, 139, 144, 149, 166, 177, 178, 222, 238 269, C.I. I. Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, 185, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment Blue 15; 3, 60, 76, and the like. Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 68, 11, 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, 69, 70, 93, 95 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.
It is preferable that the content rate of a coloring agent is 1-10 mass parts with respect to 100 mass parts of binder resin, More preferably, it is 2-8 mass parts.

〔Release agent〕
The release agent is not particularly limited, and various known waxes can be used. For example, polyolefin waxes such as polyethylene wax and polypropylene wax, branched hydrocarbon waxes such as microcrystalline wax, and paraffins. Long-chain hydrocarbon waxes such as wax and sazol wax, dialkyl ketone waxes such as distearyl ketone, carnauba wax, montan wax, behenate behenate, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, penta Ester wacks such as erythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate, tristearyl trimellitic acid, distearyl maleate , Ethylenediamine behenyl amide, an amide-based waxes such as trimellitic acid tristearyl amide.
The content ratio of the release agent is usually 1 to 30 parts by mass, more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the binder resin. When the content ratio of the release agent is within the above range, sufficient fixing separation property can be obtained.

[Charge control agent]
Various known compounds can be used as the charge control agent.
The content ratio of the charge control agent is usually 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the binder resin.

[Average toner particle size]
The average particle diameter of the toner of the present invention is preferably 3 to 9 μm, and more preferably 3 to 8 μm, for example, on a volume basis median diameter. This particle size can be controlled by the concentration of the coagulant used, the amount of organic solvent added, the fusing time, and the composition of the polymer, for example, when the emulsion polymerization aggregation method described later is employed.
When the volume-based median diameter is in the above range, the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved.

  The volume-based median diameter of the toner particles is measured and calculated using a measuring device in which “Multisizer 3” (manufactured by Beckman Coulter) is connected to a computer system equipped with data processing software “Software V3.51”. Is. Specifically, 0.02 g of toner is added to 20 mL of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing toner particles). Then, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion, and this toner dispersion is placed in a beaker containing “ISOTON II” (manufactured by Beckman Coulter) in a sample stand. Pipet until the indicated concentration 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 50 μm, the frequency value is calculated by dividing the measurement range of 1 to 30 μm into 256, and the volume integrated fraction is 50 % Particle diameter is defined as the volume-based median diameter.

[Average circularity of toner particles]
The toner of the present invention preferably has an average circularity of 0.930 to 1.000, more preferably 0.950 to 0, from the viewpoint of improving the transfer efficiency of the individual toner particles constituting the toner. .995.

In the present invention, the average circularity of toner particles is measured using “FPIA-2100” (manufactured by Sysmex).
Specifically, the sample (toner particles) is blended with an aqueous solution containing a surfactant, subjected to ultrasonic dispersion treatment for 1 minute to disperse, 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 (T). Calculated by adding the degree and dividing by the total number of toner particles.
Formula (T): Circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)

[Toner Production Method]
The toner of the present invention can be produced by a kneading / pulverization method, a suspension polymerization method, an emulsion aggregation method, an emulsion polymerization aggregation method, and other various known methods, but the shell layer is uniformly formed on the surface of the core particles. It is preferable to use an emulsion aggregation method because it can be formed.
Specifically, vinyl resin fine particles and amorphous polyester resin fine particles dispersed in an aqueous medium are agglomerated and fused to form agglomerated particles that become core particles, and are formed on the surface of the agglomerated particles that become the core particles. It is preferable to produce by an emulsion aggregation method in which toner particles are obtained by agglomerating and fusing fine particles of a vinyl-modified polyester resin to form a shell layer.

When the toner particles contain a colorant, a release agent, a charge control agent, etc., when these are contained in the core particles, the fine particles of the colorant are aggregated together when forming the agglomerated particles as the core particles. When these are contained in the shell layer, they may be added and aggregated at the same timing as the fine particles of the vinyl-modified polyester resin.
In the case of producing a toner using an emulsion polymerization aggregation method, the toner is prepared by dissolving or dispersing in a monomer solution for forming a vinyl resin in advance when forming the vinyl resin fine particles. It can also be introduced into the particles.

(External additive)
The above toner particles can constitute the toner of the present invention as they are, but in order to improve fluidity, chargeability, cleaning properties, etc., a fluidizing agent that is a so-called post-treatment agent is added to the toner particles. An external additive such as a cleaning aid may be added to constitute the toner of the present invention.

As the post-treatment agent, for example, inorganic oxide fine particles composed of silica fine particles, alumina fine particles, titanium oxide fine particles, etc., inorganic stearate compound fine particles such as aluminum stearate fine particles, zinc stearate fine particles, or strontium titanate, titanium Inorganic titanic acid compound fine particles such as zinc acid are listed. These can be used individually by 1 type or in combination of 2 or more types.
These inorganic fine particles are preferably subjected to a gloss treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, a silicone oil or the like in order to improve heat-resistant storage stability and environmental stability.

  The total amount of these various external additives added is 0.05 to 5 parts by mass, preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the toner. In addition, various external additives may be used in combination.

  According to the toner of the present invention, a specific vinyl-modified polyester resin that coats the core particle formed by compatibilizing a vinyl resin containing a high molecular weight component and an amorphous polyester resin having a low glass transition point, and the core particle Therefore, heat-resistant storage stability is obtained, and a low-gloss image can be formed while low-temperature fixability is obtained.

(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.
As the carrier, for example, magnetic particles made of conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead can be used. Among these, ferrite particles Is preferably used. As the carrier, a coated carrier in which the surface of magnetic particles is coated with a coating agent such as a resin, a resin-dispersed carrier in which magnetic fine powder is dispersed in a binder resin, and the like may be used.
The carrier preferably has a volume average particle diameter of 15 to 100 μm, more preferably 25 to 80 μm.

[Image forming apparatus]
The toner of the present invention can be used in a general electrophotographic image forming method. As an image forming apparatus in which such an image forming method is performed, for example, a photosensitive member that is an electrostatic latent image carrier, A charging means for applying a uniform potential to the surface of the photoconductor by corona discharge having the same polarity as that of the toner, and an electrostatic latent image by performing image exposure on the surface of the uniformly charged photoconductor based on image data. An exposure means for forming an image; a developing means for conveying the toner to the surface of the photoreceptor to visualize the electrostatic latent image to form a toner image; and passing the toner image through an intermediate transfer member as necessary. For example, a transfer unit that transfers to a transfer material and a fixing unit that heat-fixes the toner image on the transfer material can be used.
The toner of the present invention can be suitably used at a relatively low temperature where the fixing temperature (the surface temperature of the fixing member) is 100 to 200 ° C.

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

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

[Preparation Example 1 of vinyl resin fine particle dispersion for core]
(1) First-stage polymerization A reaction vessel equipped with a stirrer, a temperature sensor, a temperature controller, a cooling tube, and a nitrogen introducing device is charged with 2.0 parts by mass of an anionic surfactant “sodium lauryl sulfate” in advance with ion-exchanged water 2900. An anionic surfactant solution dissolved in mass parts was charged, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.
After adding 9.0 parts by mass of a polymerization initiator “potassium persulfate (KPS)” to this anionic surfactant solution and adjusting the internal temperature to 78 ° C.,
-Styrene 540 parts by mass-n-butyl acrylate 270 parts by mass-Methacrylic acid 65 parts by mass-n-octyl mercaptan 17 parts by mass of monomer solution [1] was added dropwise over 3 hours. The mixture was heated and stirred for 1 hour to conduct polymerization (first stage polymerization), thereby producing a dispersion of resin fine particles [a1].

(2) Second stage polymerization In a flask equipped with a stirrer,
・ 94 parts by mass of styrene 60 parts by mass of n-butyl acrylate 11 parts by mass of methacrylic acid 51 parts by mass of paraffin wax (melting point: 73 ° C.) as a release agent was added to a solution of 5 parts by mass of n-octyl mercaptan. The monomer solution [2] was prepared by heating to 85 ° C. and dissolving.
On the other hand, a surfactant solution in which 2 parts by mass of the anionic surfactant “sodium lauryl sulfate” was dissolved in 1100 parts by mass of ion-exchanged water was heated to 90 ° C., and 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 dispersed particle diameter of 350 nm. In this dispersion, 2.5 parts by mass of a polymerization initiator “KPS” is added to 110 parts by mass of ion-exchanged water. A dissolved aqueous initiator solution was added, and the system was heated and stirred at 90 ° C. for 2 hours to carry out polymerization (second stage polymerization), whereby a dispersion of resin fine particles [a11] was obtained.

(3) Third Stage Polymerization 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 is added to the dispersion of the above resin fine particles [a11], and 80 ° C. Under the temperature conditions of
-Styrene 230 mass parts-n-butyl acrylate 100 mass parts-n-octyl mercaptan 5.2 mass parts monomer solution [3] was dripped over 1 hour. Polymerization (third stage polymerization) is carried out by heating and stirring for 3 hours after completion of dropping, and then cooled to 28 ° C., and the vinyl resin fine particles [1] for the core are dispersed in the anionic surfactant solution. A core vinyl resin fine particle dispersion [1] was prepared.

[Preparation Examples 2-5 of vinyl resin fine particle dispersion for core]
In Preparation Example 1 of the core vinyl resin fine particle dispersion, the weight average molecular weight (Mw) and the content of the high molecular weight component are as shown in Table 1 below by changing the polymerization conditions related to the polymerization of the core vinyl resin fine particles. Core vinyl resin fine particle dispersions [2] to [5] composed of core vinyl resin fine particles were prepared.

[Preparation example 1 of amorphous polyester resin fine particle dispersion for core]
(1) Synthesis of amorphous polyester resin for core In a four-necked flask with a capacity of 10 liters equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple,
-Bisphenol A propylene oxide 2 mol adduct (BPA-PO) 428 parts by mass-Terephthalic acid (TPA) 102 parts by mass-Fumaric acid (FA) 74 parts by mass-Dodecenyl succinic anhydride 69 parts by mass-Esterification catalyst (octylic acid Tin) 2 parts by mass were put into a polycondensation reaction at 230 ° C. for 8 hours, further reacted at 8 kPa for 1 hour, and cooled to 160 ° C. to obtain an amorphous polyester resin for core [A1]. The amorphous polyester resin [A1] for core had a glass transition point (Tg) of 45 ° C., a number average molecular weight (Mn) of 2,200, and a weight average molecular weight (Mw) of 13,000.
(2) Preparation of amorphous polyester resin fine particles for core 100 parts by mass of the obtained amorphous polyester resin for core [A1] was pulverized with “Landel mill type: RM” (manufactured by Tokuju Kosakusha) and prepared in advance. The mixture was mixed with 638 parts by weight of a 0.26% by weight sodium lauryl sulfate solution, and ultrasonically dispersed at V-LEVEL, 300 μA for 30 minutes using an ultrasonic homogenizer “US-150T” (manufactured by Nippon Seiki Seisakusho) while stirring. Thus, an amorphous polyester resin fine particle dispersion [A1] for core in which fine particles of the amorphous polyester resin for core [A1] having a volume-based median diameter (D ₅₀ ) of 186 nm were dispersed was prepared.

[Preparation Examples 2-6 of Amorphous Polyester Resin Fine Particle Dispersion for Core]
In Preparation Example 1 of the amorphous polyester resin fine particle dispersion for core, the amorphous polyester resin fine particles for core [A2] in the aqueous medium were similarly used except that the monomer formulation shown in Table 2 below was followed. -Amorphous polyester resin fine particle dispersions [A2]-[A6] for core in which-[A6] are dispersed were prepared.

[Preparation example 1 of vinyl-modified polyester resin fine particle dispersion for shell]
(1) Synthesis of vinyl-modified polyester resin for shell In a 10-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple,
-Bisphenol A propylene oxide 2 mol adduct (BPA-PO) 480 parts by mass-Terephthalic acid (TPA) 123 parts by mass-Fumaric acid (FA) 81 parts by mass-Esterification catalyst (tin octylate) 2 parts by mass After allowing the polycondensation reaction at 230 ° C. for 8 hours and further at 8 kPa for 1 hour and cooling to 160 ° C.,
-Acrylic acid (AA) 8.6 parts by mass-Styrene (St) 131 parts by mass-Butyl acrylate (BA) 30 parts by mass-Polymerization initiator (di-t-butyl peroxide) A mixture of 10 parts by mass was added with a dropping funnel. It was added dropwise over 1 hour, and after the addition, the addition polymerization reaction was continued for 1 hour while maintaining at 160 ° C., then the temperature was raised to 200 ° C. and held at 10 kPa for 1 hour, and then unreacted acrylic acid, By removing styrene and butyl acrylate, a shell-modified vinyl-modified polyester resin [B1] was obtained. The vinyl-modified polyester resin [B1] for shell had a glass transition point (Tg) of 60 ° C., a number average molecular weight (Mn) of 3,000, and a weight average molecular weight (Mw) of 18,000.
(2) Preparation of vinyl-modified polyester resin fine particles for shell 100 parts by mass of the obtained vinyl-modified polyester resin for shell [B1] was pulverized with “Landel mill type: RM” (manufactured by Deoksugaku Kogyo Co., Ltd.). Mix with 638 parts by mass of sodium lauryl sulfate solution with a concentration of 26% by mass and ultrasonically disperse for 30 minutes at 300 μA with V-LEVEL using an ultrasonic homogenizer “US-150T” (manufactured by Nippon Seiki Seisakusho) while stirring. Thus, a vinyl modified polyester resin particle dispersion [B1] for shell in which fine particles of vinyl modified polyester resin for shell [B1] having a volume-based median diameter (D ₅₀ ) of 170 nm were dispersed was prepared.

[Preparation Examples 2 to 4 of vinyl-modified polyester resin fine particle dispersion for shell]
In Preparation Example 1 of the shell-modified vinyl-modified polyester resin fine particle dispersion, the shell-modified vinyl-modified polyester resin fine particles [B2] to [B2]-[ B4] -dispersed vinyl-modified polyester resin fine particle dispersions [B2] to [B4] for the shell were prepared.

[Preparation Example of Colorant Fine Particle Dispersion Bk]
90 parts by weight of sodium dodecyl sulfate was dissolved in 1600 parts by weight of ion-exchanged water while stirring, and while stirring this solution, 420 parts by weight of carbon black “Mogal L” (manufactured by Cabot) was gradually added. A colorant fine particle dispersion [Bk] in which the colorant fine particles [Bk] are dispersed was prepared by carrying out a dispersion treatment using “CLEAMIX” (manufactured by M Technique Co., Ltd.). When the volume-based median diameter of the colorant fine particles [Bk] in the colorant fine particle dispersion [Bk] was measured using a Microtrac particle size distribution measuring device “UPA-150” (manufactured by Nikkiso Co., Ltd.), it was 117 nm.

[Example 1: Toner Production Example 1]
Into a reaction vessel equipped with a stirrer, a temperature sensor, and a cooling tube, 288 parts by mass of the core vinyl resin fine particle dispersion [1] (in terms of solid content) and 2000 parts by mass of ion-exchanged water are added, and 5 mol / liter of water is added. An aqueous sodium oxide solution was added to adjust the pH to 10.
Next, 40 parts by mass of the colorant fine particle dispersion [Bk] (solid content conversion) is added, and 65 parts by mass of the amorphous polyester resin fine particle dispersion for core [A1] (solid content conversion) is added over 30 minutes. Then, an aqueous solution obtained by dissolving 60 parts by mass of magnesium chloride in 60 parts by mass of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. Thereafter, the temperature was raised after being allowed to stand for 3 minutes, and the temperature of the system was raised to 80 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 80 ° C. In this state, the particle size of the associated particles was measured with “Multisizer 3” (manufactured by Beckman Coulter), and when the volume-based median diameter (D ₅₀ ) reached 6.0 μm, the vinyl-modified polyester for shells 45 parts by mass of resin fine particle dispersion [B1] (solid content conversion) was added over 30 minutes, and when the supernatant of the reaction solution became transparent, 190 parts by mass of sodium chloride was dissolved in 760 parts by mass of ion-exchanged water. Aqueous solution was added to stop particle growth. Further, the temperature is raised and the mixture is heated and stirred in a state of 90 ° C. to advance the fusing of the particles, and the average circularity measurement apparatus “FPIA-2100” (manufactured by Sysmex) is used (HPF detection). When the average circularity measured was 4000, the mixture was cooled to 30 ° C. to obtain a dispersion of toner particles [1].
The dispersion of toner particles [1] is solid-liquid separated with a centrifuge to obtain a wet cake of toner particles, and this is used at 35 ° C. until the electric conductivity of the filtrate reaches 5 μS / cm using the centrifuge. 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 obtained.

Examples 2 to 8: Toner production examples 2 to 8
Toners [2] to [8] were produced in the same manner as in Toner Production Example 1 except that the formulation shown in Table 4 was followed.

[Comparative Example 1: Toner Production Example 9]
The toner particles were formed in the same manner as in the toner production example 1 except that the formulation shown in Table 4 was followed. However, the toner particles could not be formed. This is presumably because the affinity between the vinyl resin and the amorphous polyester resin in the core particles is low.

[Comparative Examples 2 to 9: Toner Production Examples 10 to 17]
Toners [10] to [17] were produced in the same manner as in Toner Production Example 1 except that the formulation shown in Table 4 was followed.

[Developer Production Examples 1 to 17]
(1) Production of carrier 100 parts by mass of ferrite core and 5 parts by mass of copolymer resin particles of cyclohexyl methacrylate / methyl methacrylate (copolymerization ratio 5/5) were put into a high-speed mixer equipped with stirring blades at 120 ° C. A carrier having a volume-based median diameter of 50 μm was obtained by stirring and mixing for 30 minutes to form a resin coat layer on the surface of the ferrite core by the action of mechanical impact force.
The volume-based median diameter of the carrier was measured with a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by Sympathic) equipped with a wet disperser.

(2) Mixing of toner and carrier To each of the toners [1] to [17], the above carrier is added so that the toner concentration becomes 6%. The developers [1] to [17] were produced by mixing at a rotational speed of 45 rpm for 30 minutes.

  Using the above developers [1] to [17], the low-temperature fixability, heat-resistant storage property and gloss were evaluated.

(1) Low-temperature fixability In the copying machine “bizhub PRO C6500” (manufactured by Konica Minolta), the fixing device is modified so that the surface temperature (fixing temperature) of the heating roller can be changed in the range of 120 to 200 ° C. A fixing experiment for fixing a solid image with a toner adhesion amount of 8 mg / cm ² on high-quality paper of A4 size in an environment of normal temperature and humidity (temperature 20 ° C., humidity 50% RH) is set. The process was repeated up to 200 ° C. while changing the fixing temperature from 120 ° C. 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 4. It is determined that the lower limit fixing temperature is 160 ° C. or less.

(2) Heat-resistant storage stability Take 0.5 g of toner in a 10 mL glass bottle with an inner diameter of 21 mm, close the lid, shake it 600 times at room temperature using a tap denser “KYT-2000” (manufactured by Seishin Enterprise), and then remove the lid. In the removed state, it was left for 2 hours in an environment of temperature 50 ° C. and humidity 35% RH. Next, the toner is placed on a 48-mesh (mesh 350 μm) sieve while being careful not to disintegrate the toner aggregates, set in a powder tester (manufactured by Hosokawa Micron), and fixed 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 amount of residual toner remaining on the sieve was measured, and the toner aggregation rate, which is the ratio of the residual toner amount, was calculated by the following formula (1). In addition, if it is 20% or less, it will be judged that there is no problem practically and it is a pass. The results are shown in Table 4.
Formula (1): toner aggregation rate (%) = {residual toner amount (g) /0.5 (g)} × 100

(3) Glossiness As the image forming apparatus, a commercially available multifunction machine “bishub PRO C6500” (manufactured by Konica Minolta Co., Ltd.) is used. An image was formed on “POD128 g gloss coat (128 g / m ² )” (manufactured by Oji Paper Co., Ltd.) in an environment of normal temperature and humidity (temperature 20 ° C., humidity 50% RH) at a surface temperature of 180 ° C. The glossiness of a solid image set to a toner amount of 1.2 mg / cm ² on the transfer paper was measured. The gloss value was evaluated according to the following rank. The results are shown in Table 4. A glossiness of 17% or less is accepted.
The glossiness was measured at an incident angle of 75 ° using a gloss meter “Gloss Meter” (manufactured by Murakami Color Engineering Laboratory) on the basis of a glass surface with a refractive index of 1.567.

Claims (3)

A core particle made of a vinyl resin and an amorphous polyester resin compatible with the vinyl resin, and a shell layer made of an amorphous resin formed by bonding a vinyl polymer segment and a polyester polymer segment covering the core particle. Consisting of core-shell toner particles,
The vinyl resin constituting the core particle has a weight average molecular weight (Mw) calculated from a molecular weight distribution measured by gel permeation chromatography (GPC) of 20,000 to 60,000, and the molecular weight distribution In which the ratio of the resin component having a molecular weight of 100,000 or more is 3 to 13 area%,
The glass transition point of the amorphous polyester resin constituting the core particles is 35 to 50 ° C., and the content of the amorphous polyester resin in the total amount of the resin constituting the toner particles is 5 to 30% by mass. Yes,
An electrostatic charge image developing toner, wherein the amorphous resin constituting the shell layer has a glass transition point of 55 to 65 ° C.   The weight average molecular weight (Mw) calculated from the molecular weight distribution measured by gel permeation chromatography (GPC) of the amorphous polyester resin constituting the core particles is 7,000 to 20,000, The toner for developing an electrostatic image according to claim 1. 3. The toner for developing an electrostatic charge image according to claim 1, wherein a content ratio of the vinyl polymer segment in the amorphous resin constituting the shell layer is 5 to 30% by mass. 4.