JP6048316B2 - 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, electrophotographic image forming technology has been improved and applied to the light printing field. Accordingly, there is a demand for outputting a high-quality image with higher speed, lower energy, and capable of competing with a current printing press.

  In response to such a request to output an image with low energy, from the viewpoint of obtaining low-temperature fixability without impairing the heat-resistant storage property of the toner, core particles made of a vinyl resin and a shell layer made of a polyester resin covering the core particle A toner having a core-shell structure consisting of the following has been studied (Patent Document 1).

However, in such a toner, since the vinyl resin and the polyester resin have poor affinity, it is difficult to make the shell layer uniform. As a result, such a toner has a problem that the shell layer is peeled off by stirring in the developing device, and image noise is generated in the formed image.
In addition, the compatibility between the vinyl resin and the polyester resin is low at the time of heat fixing, and there is a problem in that a portion that does not conform to the whole is generated, so that a minute image gloss unevenness occurs in the formed image.

  In order to solve such problems, for the purpose of improving the affinity between the core particles and the shell layer, a toner using a urethane-modified polyester resin or an acrylic-modified polyester resin as a resin constituting the shell layer (Patent Document 2) or In addition, a toner using a styrene-acrylic resin and a styrene-acrylic modified polyester resin as a resin constituting the core particles and a styrene-acrylic modified polyester resin as a resin constituting the shell layer (Patent Document 3) has been proposed. ing.

  However, in the production printing area, the speed of the image forming apparatus, the expansion of the corresponding paper type, the improvement in image quality, and the like are further advanced. In such an advanced image forming method, even if the above-described toner is used, both heat storage stability and low-temperature fixability can be achieved over a long period of time, and image noise and image gloss unevenness are generated. It is not enough in terms of deterring.

JP 2005-338548 A JP 2005-173202 A JP 2013-33233 A

  The present invention has been made in consideration of the above-described circumstances. The object of the present invention is to provide low-temperature fixability and a long period of time even when used in a highly functional image forming method. An object of the present invention is to provide a toner for developing an electrostatic charge image, which has heat storage stability and crush resistance and can suppress the occurrence of uneven image gloss.

The toner for developing an electrostatic charge image of the present invention comprises a core particle comprising a vinyl resin and an amorphous resin (A) formed by bonding a vinyl polymer segment and a polyester polymer segment, which is compatible with the vinyl resin, and The core particles are composed of toner particles having a core-shell structure consisting of a shell layer made of an amorphous resin (B) in which a vinyl polymer segment and a polyester polymer segment are bonded.
The vinyl polymer segment content ratio Va in the amorphous resin (A) is 40 mass% or more and 65 mass% or less, and
The ratio Va / Vb of the content ratio Va of the vinyl polymerization segment in the amorphous resin (A) to the content ratio Vb of the vinyl polymerization segment in the amorphous resin (B) is 1.0 or more. And

  In the electrostatic image developing toner of the present invention, the ratio Va / Vb is preferably 1.2 to 4.0.

  In the toner for developing an electrostatic charge image of the present invention, the content of the amorphous resin (A) is preferably 5% by mass or more and 30% by mass or less with respect to the total resin constituting the toner particles.

In the electrostatic image developing toner of the present invention, the glass transition point of the amorphous resin (A) is 35 ° C. or more and 50 ° C. or less,
The amorphous resin (B) preferably has a glass transition point of 55 ° C. or higher and 65 ° C. or lower.

In the electrostatic image developing toner of the present invention, the toner particles contain a release agent,
The release agent is preferably contained in the core particles.

  According to the toner for developing an electrostatic charge image of the present invention, the core particles formed by miscibility of the vinyl resin and the amorphous resin (A) having a high content ratio of the vinyl polymer segment, and the core particles are coated. Since it has a core-shell structure consisting of a shell layer made of an amorphous resin (B) having a low content of vinyl polymer segments, low-temperature fixability can be obtained even when used in a highly functional image forming method. In addition, heat storage stability and crush resistance can be obtained over a long period of time, and the occurrence of uneven image gloss can be suppressed.

  Hereinafter, the present invention will be specifically described.

The toner of the present invention has a vinyl resin as a main resin, and is composed of a vinyl resin as a main resin, and a non-crystalline resin (A) formed by bonding a vinyl polymer segment compatible with the vinyl resin and a polyester polymer segment. ) (Hereinafter, also referred to as “vinyl-modified polyester resin (A)”), and an amorphous resin (B) (which is formed by bonding a vinyl polymer segment and a polyester polymer segment covering the core particle) (Hereinafter also referred to as “vinyl-modified polyester resin (B)”).
Specifically, the vinyl polymer segment content ratio Va in the vinyl-modified polyester resin (A) constituting the core particle is 40% by mass to 65% by mass, and the vinyl polymer segment in the vinyl-modified polyester resin (A). The ratio Va / Vb (hereinafter also referred to as “the ratio Va / Vb of the vinyl polymerization segment”) to the vinyl polymerization segment content ratio Vb in the vinyl-modified polyester resin (B) constituting the shell layer, It is 1.0 or more, preferably 1.2 to 4.0.

According to the toner as described above, the core particles formed by compatibilizing the vinyl resin and the vinyl-modified polyester resin (A) having a high content of the vinyl polymer segment, and the vinyl polymer segment covering the core particle, Since it has a core-shell structure consisting of a shell layer made of a vinyl-modified polyester resin (B) with a low content ratio, when outputting at high speed, when outputting to cardboard, or when outputting a high-quality image, Even when used in a highly functional image forming method, low-temperature fixability can be obtained, heat-resistant storage and crush resistance can be obtained over a long period of time, and the occurrence of uneven image gloss can be suppressed.
The reason is considered as follows.
That is, low-temperature fixability is ensured by the polyester polymerized segments in each of the vinyl-modified polyester resin (A) of the core particle and the vinyl-modified polyester resin (B) of the shell layer. In addition, since the vinyl-modified polyester resin (A) has a high vinyl polymer segment content ratio Va, it is highly compatible with the vinyl resin that is the main resin, and therefore depends on the vinyl-modified polyester resin (A). Low temperature fixability can be exhibited very efficiently. Also, since the vinyl-modified polyester resin (B) has a vinyl polymerization segment, compatibility with the vinyl resin as the main resin is obtained at the time of heat fixing, and the low-temperature fixability by the vinyl-modified polyester resin (B) is also obtained. Demonstrated.
In addition, as described above, the vinyl-modified polyester resin (B) of the shell layer is compatible with the vinyl resin and the vinyl-modified polyester resin (A) of the core particles at the time of heat fixing, and thus the portion that is not familiar with the whole. Is suppressed, and the occurrence of minute image gloss unevenness in the formed image is suppressed.
In addition, the vinyl polymer segment content ratio Vb of the vinyl-modified polyester resin (B) of the shell layer is designed to be lower than the vinyl polymer segment content ratio Va of the vinyl-modified polyester resin (A) of the core particle. When the toner is stored, the compatibility of the core particles with the vinyl resin and the vinyl-modified polyester resin (A) is prevented, and heat-resistant storage stability is obtained. On the other hand, since the affinity with the vinyl resin and the vinyl-modified polyester resin (A) constituting the core particles is sufficiently obtained, the shell layer has high uniformity and high adhesion to the core particles, In addition to being able to obtain heat-resistant storage stability for a long period of time, crush resistance can be obtained for a long period of time, and the occurrence of image noise can be suppressed by preventing the peeling of the shell layer due to stirring in the developing device. .

In the present invention, the ratio Va / Vb of the vinyl polymerization segment indicates the balance of affinity for the main resin (vinyl resin), and the ratio Va / Vb of the vinyl polymerization segment is 1.0 or more. While the compatibility state of the modified polyester resin (A) with the main resin is obtained, a shell layer made of the vinyl-modified polyester resin (B) can be formed. This effect is further obtained when the ratio Va / Vb of the vinyl polymerization segment is 1.2 or more.
When the ratio Va / Vb of the vinyl polymer segment is 4.0 or less, high affinity between the vinyl-modified polyester resin (A) and the vinyl-modified polyester resin (B) is obtained, and the adhesion of the shell layer to the core particles Therefore, excellent crush resistance can be surely obtained.
On the other hand, when the ratio Va / Vb of the vinyl polymer segment is less than 1.0, the compatibility with the vinyl resin is higher in the vinyl-modified polyester resin (B) than in the vinyl-modified polyester resin (A). Then, the vinyl-modified polyester resin (B) is compatible with the core particles, and it becomes difficult to form a shell layer, resulting in a problem that sufficient heat-resistant storage property cannot be obtained.

[Core particles]
The core particles constituting the toner particles according to the present invention contain a vinyl resin and a vinyl-modified polyester resin (A) formed by bonding a vinyl polymer segment and a polyester polymer segment. Resin (A) is mutually compatible.

[Vinyl resin]
The vinyl resin constituting the core particle is formed using a monomer having a vinyl group (hereinafter referred to as “vinyl monomer”). Specifically, the vinyl resin is a styrene-acrylic resin. It can consist of a copolymer, a styrene polymer, an acrylic polymer, etc., and it is preferable that it consists of a styrene-acrylic copolymer.

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. Specific examples include 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.

  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 vinyl resin preferably 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.
When the vinyl resin has a weight average molecular weight (Mw) of 20,000 or more, compatibility between the vinyl resin and the vinyl-modified polyester resin (B) constituting the shell layer does not occur, and sufficient heat-resistant storage stability is obtained. It is definitely obtained. Further, when the weight average molecular weight (Mw) of the vinyl resin is 60,000 or less, sufficient 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.

[Glass transition point of vinyl resin]
The glass transition point of the vinyl resin is preferably 35 ° C. or higher and 50 ° C. or lower.
When the glass transition point of the vinyl resin is 35 ° C. or higher, sufficient heat-resistant storage stability can be obtained with certainty. On the other hand, when the glass transition point of the vinyl resin is 50 ° C. or less, sufficient low-temperature fixability can be reliably obtained.

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

[Vinyl modified polyester resin (A)]
The vinyl-modified polyester resin (A) is a resin formed by bonding a vinyl polymerization segment and a polyester polymerization segment.

  The vinyl polymerization segment is formed of a vinyl monomer, and examples of the vinyl monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decyl Styrene monomers such as styrene, pn-dodecylstyrene, 2,4-dimethylstyrene, 3,4-dichlorostyrene, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylic Cyclohexyl acid, phenyl acrylate, methyl methacrylate, ethyl methacrylate, (Meth) acrylic acid such as butyl tacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate An ester monomer is mentioned, In addition to these, what was illustrated as a vinyl monomer for forming said 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 vinyl polymer segment can be composed of a styrene polymer, an acrylic polymer, a styrene-acrylic copolymer, etc., and is preferably composed of a styrene-acrylic copolymer.

[Polyester polymerization segment]
The polyester polymerized segment is an amorphous one formed by a polyvalent carboxylic acid containing two or more carboxy groups in one molecule and a polyhydric alcohol containing two or more hydroxyl groups in one molecule. Specifically, it means one having no clear endothermic peak in differential scanning calorimetry (DSC).

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- Unsaturated aliphatic 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 trivalent or higher carboxylic acids, such as pyrene-tetracarboxylic acid.
A polyvalent carboxylic acid may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of the polyhydric alcohol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8- Octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18- Aliphatic diols such as octadecanediol and 1,20-eicosanediol; Bisphenols such as bisphenol A and bisphenol F; and alkylene oxide adducts of bisphenols such as ethylene oxide adducts and propylene oxide adducts; glycerin, Pentaerythritol It can be exemplified hexamethylol melamine, hexa ethylene melamine, tetramethylol benzoguanamine, etc. trihydric or higher polyols, such as tetra-ethyl benzoguanamine the.
A polyhydric alcohol may be used individually by 1 type, and may be used in combination of 2 or more type.

The content ratio Va of the vinyl polymerization segment in the vinyl-modified polyester resin (A) is 40% by mass to 65% by mass, and preferably 45% by mass to 60% 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 Va of the vinyl polymer segment is 65% by mass or less, the polyester polymer segment is contained in an intended amount, and low temperature fixability is obtained. On the other hand, when the content ratio Va of the vinyl polymer segment is 40% by mass or more, high compatibility with the vinyl resin that is the main resin constituting the core particle can be obtained, and low-temperature fixability can be reliably exhibited. .
The content ratio of the vinyl polymerization segment in the vinyl-modified polyester resin can be controlled by adjusting the amount of the monomer to be reacted when the vinyl-modified polyester resin is synthesized.

[Glass transition point of vinyl-modified polyester resin (A)]
The glass transition point of the vinyl-modified polyester resin (A) is preferably 35 ° C. or higher and 50 ° C. or lower.
When the glass transition point of the vinyl-modified polyester resin (A) is 35 ° C. or higher, the resulting toner has a high thermal strength and sufficient heat-resistant storage stability is obtained. On the other hand, when the glass transition point is 50 ° C. or lower, sufficient low-temperature fixability can be obtained.
The glass transition point of the vinyl-modified polyester resin can be controlled by adjusting the kind and amount of the monomer to be reacted when synthesizing the vinyl-modified polyester resin, and the molecular weight.

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

[Molecular weight of vinyl-modified polyester resin (A)]
The weight average molecular weight (Mw) calculated from the molecular weight distribution measured by GPC of the vinyl-modified polyester resin (A) is preferably 7,000 to 20,000.
When the weight average molecular weight (Mw) of the vinyl-modified polyester resin (A) is 7,000 or more, incompatibility with the vinyl-modified polyester resin (B) constituting the shell layer can be ensured. In addition, the effect of heat-resistant storage stability can be obtained with certainty. On the other hand, when the weight average molecular weight (Mw) is 20,000 or less, the effect on the low-temperature fixability can be reliably obtained.

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

[Content ratio of vinyl-modified polyester resin (A)]
The content ratio of the vinyl-modified polyester resin (A) to the total resin constituting the toner particles, that is, the binder resin, is 5% by mass or more and 30% by mass or less, and preferably 5% by mass or more and 20% by mass or less.
When the content ratio of the vinyl-modified polyester resin (A) is 5% by mass or more, sufficient low-temperature fixability is obtained, and affinity with the vinyl-modified polyester resin (B) is obtained, so that the shell layer is high. It can be formed with uniformity. On the other hand, heat resistance storage property is not impaired by being 30 mass% or less.

[Method for producing vinyl-modified polyester resin]
The vinyl-modified polyester resin can be produced by bonding a polyester polymer segment and a vinyl polymer segment via both reactive monomers. Specifically, the polyvalent carboxylic acid / polyvalent for forming the polyester polymer segment at least at any time before, during and after the step of addition polymerization of the vinyl monomer for forming the vinyl polymer segment It can be produced by performing a condensation polymerization reaction in the presence of alcohol.
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 polyester polymerization segment is performed. A method in which a tri- or higher valent vinyl monomer serving as a crosslinking agent is added to the reaction system to further advance the condensation polymerization reaction.
(2) After the polycondensation reaction of polyvalent carboxylic acid and polyhydric alcohol to form a polyester polymer segment, an addition polymerization reaction of a vinyl monomer to form a vinyl polymer segment is performed, and then necessary According to the method, a trivalent or higher valent vinyl monomer serving as a cross-linking agent is added to the reaction system, and the polycondensation reaction further proceeds under temperature conditions suitable for the polycondensation reaction.
(3) An addition polymerization reaction of a vinyl monomer for forming a vinyl polymerization segment and a polyvalent carboxylic acid and a polyhydric alcohol for forming a polyester polymerization segment under temperature conditions suitable for the addition polymerization reaction. After the polycondensation reaction is carried out 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, under temperature conditions suitable for the polycondensation reaction. A method of further proceeding the condensation polymerization reaction.

  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 carboxy group, an epoxy group, a primary amino group and a secondary amino group in the molecule, preferably a hydroxyl group and / or a carboxy group. It is preferably a compound having a group, more preferably a carboxy 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, and these may be used alone or in combination. it can.

[Shell layer]
The shell layer constituting the toner particles according to the present invention contains a vinyl-modified polyester resin (B) formed by bonding a vinyl polymer segment and a polyester polymer segment.
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 (B) constituting the shell layer has low compatibility with both the vinyl resin constituting the core particles and the vinyl-modified polyester resin (A) in the temperature range during storage of the toner.

  The vinyl-modified polyester resin (B) is formed in the same manner as the vinyl-modified polyester resin (A) constituting the above-described core particle, and the type and / or use of the monomer for forming the vinyl-modified polyester resin (B) The amount is different.

The vinyl polymer segment content ratio Vb in the vinyl-modified polyester resin (B) may be in a range where the ratio Va / Vb of the vinyl polymer segment is 1.0 or more, and is particularly 5 mass% or more and 50 mass% or less. It is preferable that it is 10% by mass or more and 35% by mass or less.
When the content Vb of the vinyl polymerized segment in the vinyl-modified polyester resin (B) is 5% by mass or more, the shell layer can have high uniformity and high adhesion to the core particles, and can have high resistance. Crushability can be reliably obtained. On the other hand, when the vinyl polymer segment content ratio Vb in the vinyl-modified polyester resin (B) is 50% by mass or less, the compatibility of the core particles with the vinyl resin and the vinyl-modified polyester resin (A) during storage of the toner is improved. It is prevented and high heat storage stability is obtained.

[Glass transition point of vinyl-modified polyester resin (B)]
The glass transition point of the vinyl-modified polyester resin (B) is preferably 55 ° C or higher and 65 ° C or lower.
When the glass transition point of the vinyl-modified polyester resin (B) is in the above range, sufficient low-temperature fixability can be obtained during heat fixing while ensuring sufficient heat-resistant storage stability during toner storage.

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

[Molecular weight of vinyl-modified polyester resin (B)]
The weight average molecular weight (Mw) calculated from the molecular weight distribution measured by GPC of the vinyl-modified polyester resin (B) is preferably 10,000 to 100,000.
When the weight average molecular weight (Mw) of the vinyl-modified polyester resin (B) is 10,000 or more, excessive compatibility with the resin constituting the core particle is suppressed, and the shell layer completely covering the core particle As a result, the effect on heat-resistant storage stability can be obtained with certainty. On the other hand, when the weight average molecular weight (Mw) is 100,000 or less, the affinity with the core particles is high and the adhesion between the shell layer and the core particles is high, and the effect of suppressing the occurrence of uneven image gloss is ensured. Is obtained.

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

[Content ratio of vinyl-modified polyester resin (B)]
The content ratio of the vinyl-modified polyester resin (B) to the total resin constituting the toner particles, that is, the binder resin, is 5% by mass or more and 15% by mass or less, and preferably 5% by mass or more and 10% by mass or less.
The content ratio of the vinyl-modified polyester resin (B) is in the above range, so that the shell layer can cover the entire surface of the core particles, and becomes thin and highly uniform, with low temperature fixability and heat resistant storage. Property and crushing resistance can be obtained in a reliable manner.

[Ratio of core particle to shell layer in toner particles]
The mass ratio of the core particles to the shell layer (core particles: shell layer) in the toner particles according to the present invention is preferably in the range of 85:15 to 95: 5.
When the mass ratio of the core particles in the toner particles is 95% by mass or less, toner particles having a structure in which the core particles are completely covered with the shell layer can be obtained, and as a result, heat-resistant storage stability can be reliably obtained. . On the other hand, when the mass ratio of the core particles in the toner particles is 85% by mass or more, sufficient low-temperature fixability can be reliably obtained.

  The molecular weight distribution, glass transition point and softening point of each resin should be measured using vinyl resin, vinyl-modified polyester resin (A) and vinyl-modified polyester resin (B) extracted from toner particles as measurement samples, respectively. Can do.

  The toner particles may contain a resin other than the above-mentioned vinyl resin and vinyl-modified polyester resin (A) or vinyl-modified polyester resin (B) as a binder resin.

[Configuration of toner particles]
The toner particles according to the present invention contain internal additives such as a colorant, a release agent, and a charge control agent in addition to the resin (binder resin) constituting the core particles and the shell layer. May be.
The colorant, the release agent, and the charge control agent may each be contained in the core particle, may be contained in the shell layer, or may be contained in both. It is preferable that it is 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, the fine particles of the vinyl resin and the fine particles of the vinyl-modified polyester resin (A) dispersed in the aqueous medium are aggregated and fused to form aggregated particles that become core particles, and the aggregated 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 the fine particles of the vinyl-modified polyester resin (B) on which a shell layer is to be formed.
The aggregated particles serving as the core particles tend to be oriented on the surface side of the aggregated particles due to the high polarity of the polyester polymer segment of the vinyl-modified polyester resin (A) when dispersed in an aqueous medium. Therefore, by producing the toner by the emulsion aggregation method, the shell layer made of the vinyl-modified polyester resin (B) having a relatively high content of the polyester polymer segment can be made extremely thin and highly uniform.

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 agglomerated at the same timing as the fine particles of the vinyl-modified polyester resin (B).
In addition, in the case of producing a toner using an emulsion polymerization aggregation method, when forming vinyl resin fine particles, a colorant, a release agent, and charge control are previously added to the monomer solution for forming the vinyl resin. These can be introduced into the toner particles by dissolving or dispersing the agent.

(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, the core particles formed by compatibilization of the vinyl resin and the vinyl-modified polyester resin (A), and the vinyl-modified polyester resin having a low content of the vinyl polymerized segment covering the core particles ( Since it has a core-shell structure consisting of a shell layer according to B), even when used in a highly functional image forming method, low temperature fixability can be obtained, and heat storage stability and crush resistance can be obtained over a long period of time. Furthermore, the occurrence of uneven image gloss can be suppressed.

(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.
In addition, the toner of the present invention is suitably used for a highly functional image forming method such as when outputting at high speed, when outputting to a thick paper as a transfer material, or when outputting a high quality image. Can do.

  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-modified polyester resin fine particle dispersion]
(1) Synthesis of vinyl-modified polyester resin In a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple,
・ Bisphenol A propylene oxide 2-mole adduct (BPA-PO) 389 g
・ 86g of terephthalic acid (TPA)
・ Fumaric acid (FA) 51g
・ Esterification catalyst (tin octylate) 2g
, And subjected to a polycondensation reaction at 230 ° C. for 8 hours, and further at 8 kPa for 1 hour, cooled to 160 ° C.,
・ Acrylic acid (AA) 25g
・ 310 g of styrene (St)
・ Butyl acrylate (BA) 139g
・ Polymerization initiator (di-t-butyl peroxide) 100 g
Was added dropwise over 1 hour using a dropping funnel, and after the addition, the addition polymerization reaction was continued for 1 hour while maintaining the temperature at 160 ° C., then the temperature was raised to 200 ° C. and maintained at 10 kPa for 1 hour, By removing unreacted acrylic acid, styrene, and butyl acrylate, a vinyl-modified polyester resin [1] obtained by chemically bonding a vinyl polymer segment and a polyester polymer segment was obtained. The glass transition point of the vinyl-modified polyester resin [1] was 43 ° C.
(2) Preparation of vinyl-modified polyester resin fine particles 100 parts by mass of the obtained vinyl-modified polyester resin [1] was pulverized with “Landel mill type: RM” (manufactured by Tokuju Kogakusha Co., Ltd.) and 0.26% by mass prepared in advance. The mixture was mixed with 638 parts by mass of sodium lauryl sulfate solution having a concentration, and ultrasonically dispersed at V-LEVEL, 300 μA for 30 minutes using an ultrasonic homogenizer “US-150T” (manufactured by Nippon Seiki Seisakusho) while stirring. A vinyl-modified polyester resin fine particle dispersion [1] in which fine particles of a vinyl-modified polyester resin [1] having a median diameter of 180 nm are dispersed was prepared.

[Preparation Examples 2 to 10 of vinyl-modified polyester resin fine particle dispersion]
In the same manner as in Preparation Example 1 of the vinyl-modified polyester resin fine particle dispersion, except that the monomer formulation in Table 1 below was followed, the vinyl-modified segment formed by chemically bonding the vinyl polymerized segment and the polyester polymerized segment. Polyester resins [2] to [10] were obtained, and vinyl modified polyester resin fine particle dispersion [2] in which fine particles of vinyl modified polyester resins [2] to [10] were dispersed in an aqueous medium using the same. To [10] were prepared.

[Preparation Example 1 of vinyl resin fine particle dispersion]
(1) First-stage polymerization A 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device was charged with 4 g of sodium polyoxyethylene-2-dodecyl ether sulfate and 3000 g of ion-exchanged water, and a nitrogen stream The internal temperature was raised to 80 ° C. while stirring at a lower stirring speed of 230 rpm.
After raising the temperature, 10 g of potassium persulfate (KPS) dissolved in 200 g of ion-exchanged water was added, and the liquid temperature was adjusted to 75 ° C.
・ Styrene 568g
・ 164 g of n-butyl acrylate
・ Methacrylic acid 68g
A monomer mixed solution [a] consisting of 1 is added dropwise over 1 hour, and after completion of the dropwise addition, polymerization (first stage polymerization) is carried out by heating and stirring at 75 ° C. for 2 hours, whereby resin fine particles [a A dispersion was prepared.

(2) Second-stage polymerization A solution prepared by dissolving 2 g of sodium polyoxyethylene-2-dodecyl ether sulfate in 3000 g of ion-exchanged water in a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device. After charging and heating to 80 ° C., the resin fine particles [a] are 42 g in terms of solid content,
・ Styrene 195g
・ N-butyl acrylate 91g
・ Methacrylic acid 20g
・ 3g of n-octyl mercaptan
In the monomer mixture consisting of:-Wax: 70 g of behenyl behenate
And the monomer mixture solution [b] dissolved at 80 ° C., and mixed and dispersed for 1 hour by a mechanical disperser “CLEAMIX” (manufactured by M Technique Co., Ltd.) having a circulation route to emulsify. A dispersion containing particles (oil droplets) was prepared.
Next, an initiator solution in which 5 g of potassium persulfate is dissolved in 100 g of ion-exchanged water is added to this dispersion, and this system is heated and stirred at 80 ° C. for 1 hour to perform polymerization (second stage polymerization). In this way, a dispersion of resin fine particles [b] was obtained.

(3) Third-stage polymerization An initiator solution in which 10 g of potassium persulfate is dissolved in 200 g of ion-exchanged water is added to the dispersion of the resin fine particles [b].
・ 315 g of styrene
・ 145g of n-butyl acrylate
・ Methacrylic acid 32g
・ 6g of n-octyl mercaptan
A monomer mixture [c] consisting of 1 was added dropwise over 1 hour. Polymerization (third stage polymerization) is carried out by heating and stirring for 2 hours after the completion of the dropping, and then cooled to 28 ° C., so that the vinyl resin fine particles [C] are dispersed in the aqueous medium. A dispersion [C] was 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]
(Aggregation / fusion process)
280 g of a vinyl resin fine particle dispersion [C] for forming core particles in a reaction vessel equipped with a stirrer, a temperature sensor, and a cooling pipe (C), and vinyl-modified polyester resin fine particles for forming core particles. After adding 80 g of the dispersion [1] (in terms of solid content) and 2000 g of ion-exchanged water, the pH was adjusted to 10 by adding a 5 mol / liter aqueous sodium hydroxide solution.
Next, 40 g of a colorant fine particle dispersion [Bk] (in terms of solid content) was added, and an aqueous solution in which 60 g of magnesium chloride was dissolved in 60 g of ion-exchanged water was added at 30 ° C. over 10 minutes 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 is measured with “Multisizer 3” (manufactured by Beckman Coulter). When the volume-based median diameter becomes 6.0 μm, the vinyl modification for forming the shell layer is performed. Polyester resin fine particle dispersion [6] 40 g (solid content conversion) is added over 30 minutes, and when the supernatant of the reaction solution becomes transparent, an aqueous solution in which 190 g of sodium chloride is dissolved in 760 g of ion-exchanged water is added. Grain growth was stopped. 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].
(Washing / drying process)
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%.
(External additive addition process)
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 2-7, Comparative Examples 1-3: Toner Production Examples 2-10]
Toners [2] to [10] were produced in the same manner as in Toner Production Example 1 except that the prescription in Table 2 was followed.

[Developer Production Examples 1 to 10]
(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 [10], the above carrier is added so that the toner concentration becomes 6% by mass, and a micro-type V-type mixer (Tsutsui Riken Co., Ltd.) is added. The developers [1] to [10] were produced by mixing at a rotational speed of 45 rpm for 30 minutes.

  Using the above developers [1] to [10], the low-temperature fixability to thick paper, image gloss unevenness, image noise, and heat-resistant storage stability were evaluated.

(1) Low-temperature fixability to cardboard In a commercially available color multifunction device “bizhub PRO C6500” (manufactured by Konica Minolta), the fixing temperature can be changed within the range of 150 to 200 ° C. A fixing experiment in which a solid image with a toner adhesion amount of 8 g / m ² is output onto a cardboard “mondi Color Copy 350 g / m ² ” (manufactured by Mondi) using the above-mentioned developer modified. The fixing temperature was repeatedly increased from 150 ° C. to 200 ° C. while being changed in steps of 5 ° C. The fixing speed was 620 mm / sec, and the temperature of the lower fixing roller was set 20 ° C. lower than the fixing temperature of the upper fixing belt.
Then, among the fixing experiments in which no cold offset occurs, the fixing temperature of the fixing experiment relating to the lowest fixing temperature was evaluated as the fixing lower limit temperature. The results are shown in Table 3. It can be said that the lower the fixing minimum temperature, the better the low-temperature fixing property. In the present invention, a fixing lower limit temperature of less than 165 ° C. is determined to be acceptable.

(2) Image gloss unevenness Using a commercially available color complex machine “bizhub PRO C6500” (manufactured by Konica Minolta), the developer is loaded and “POD128 g gloss coat (128 g / m ² )” (manufactured by Oji Paper Co., Ltd.) ) A solid image having a toner adhesion amount of 4 g / m ² was output. The fixing speed was 620 mm / sec, the fixing temperature of the upper fixing belt was 200 ° C., and the temperature of the lower fixing roller was set 20 ° C. lower than the fixing temperature of the upper fixing belt.
The obtained solid image was observed visually and with a magnifying glass, and evaluated according to the following evaluation criteria. The results are shown in Table 3.
-Evaluation criteria-
A: Image gloss unevenness is not detected at all with visual or loupe (pass)
○: Image gloss unevenness is not detected at all visually, and image gloss unevenness is detected when magnified with a loupe (pass)
×: Domain-like image gloss unevenness is detected visually (failure)

(3) Image noise (fogging density)
For “CF paper (80 g / m ² )” (manufactured by Konica Minolta Co., Ltd.), absolute image densities at 20 locations were measured using a Macbeth reflection densitometer “RD-918” (manufactured by Macbeth Co., Ltd.) on a blank sheet that was not printed. And averaged to obtain a blank paper density. Next, 100,000 prints for forming a belt-like solid image with a printing rate of 5% were performed. Similarly, the absolute image density at 20 locations was measured and averaged for the white background portion of the 100,000th solid image, and the value obtained by subtracting the white paper density from this average density was evaluated as the fog density. The results are shown in Table 3. A fog density of less than 0.010 was determined to be practically acceptable.

(4) Heat-resistant storage property Take 0.5 g of toner in a 10 mL glass bottle with an inner diameter of 21 mm, close the lid, and shake it 600 times at room temperature using a tap denser “KYT-2000” (manufactured by Seishin Enterprise Co., Ltd.). And left in an environment of a temperature of 50 ° C. and a humidity of 35% RH for 2 hours. 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 mass% or less, there is no problem practically and it is judged that it is a pass. The results are shown in Table 3.
Formula (1): toner aggregation rate (%) = {residual toner amount (g) /0.5 (g)} × 100

Claims (5)

Core particles composed of a vinyl resin, an amorphous resin (A) formed by combining a vinyl polymer segment and a polyester polymer segment, which is compatible with the vinyl resin, and a vinyl polymer segment covering the core particle And core-shell structure toner particles composed of a shell layer made of an amorphous resin (B) formed by bonding a polyester polymer segment,
The vinyl polymer segment content ratio Va in the amorphous resin (A) is 40 mass% or more and 65 mass% or less, and
The ratio Va / Vb of the content ratio Va of the vinyl polymerization segment in the amorphous resin (A) to the content ratio Vb of the vinyl polymerization segment in the amorphous resin (B) is 1.0 or more. An electrostatic charge image developing toner.   The electrostatic charge image developing toner according to claim 1, wherein the ratio Va / Vb is 1.2 to 4.0.   3. The static according to claim 1, wherein a content ratio of the amorphous resin (A) is 5% by mass or more and 30% by mass or less with respect to the total resin constituting the toner particles. Toner for charge image development. The amorphous resin (A) has a glass transition point of 35 ° C. or more and 50 ° C. or less,
4. The electrostatic charge image developing toner according to claim 1, wherein a glass transition point of the amorphous resin (B) is 55 ° C. or more and 65 ° C. or less. 5. The toner particles contain a release agent;
The electrostatic charge image developing toner according to claim 1, wherein the release agent is contained in core particles.