JP6597319B2 - Toner for developing electrostatic latent image and method for producing the same - Google Patents

Description

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

  In recent years, electrophotographic image forming apparatuses have been increasingly demanded for higher speed, higher image quality, and wider application, and electrostatic latent image developing toner (hereinafter also simply referred to as “toner”) used therefor. Toners that can meet the demands of the market are being developed. From the viewpoint of global warming prevention measures, there is an increasing demand for energy saving for electrophotographic image forming apparatuses, and development of low-temperature fixing toner capable of fixing with less energy is in progress. As a typical study for lowering the fixing temperature of toner, one using a crystalline material can be cited. In addition, when pursuing low-temperature fixability, it is easy to melt with heat, so heat-resistant storage properties may be an issue. Therefore, development of a toner using an amorphous polyester resin capable of achieving both low-temperature fixability and heat-resistant storage stability at a high level is being promoted.

  For example, Patent Document 1 is a toner containing a crystalline polyester resin and a release agent, and there is a structure in which the crystalline polyester resin is in contact with the release agent on the cross section of the toner dyed with ruthenium. When the cross-sectional area of the structure is A, the cross-sectional area of the release agent alone is B, and the cross-sectional area of the crystalline polyester resin alone is C, 40 ≦ 100 × A / (A + B + C) ≦ 70, 10 ≦ 100 There is disclosed an electrostatic charge developing toner characterized in that xB / (A + B + C) ≦ 30 and 20 ≦ 100 × C / (A + B + C) ≦ 30.

  Patent Document 2 discloses that toner particles are dispersed in a matrix phase made of vinyl resin in which a first domain phase made of crystalline polyester resin A and a second domain phase made of crystalline polyester resin B are dispersed. The crystalline polyester resin A and the crystalline polyester resin having a domain-matrix structure, an average diameter of the first domain phase being 400 to 900 nm, an average diameter of the second domain phase being 10 to 200 nm An electrostatic charge image developing toner is disclosed in which all of B have a melting point of 95 ° C. or less.

JP 2008-033057 A JP2015-011054A

  Patent Documents 1 and 2 both use a crystalline polyester resin as a crystalline material, and control the presence state in toner particles to achieve both image folding resistance and heat-resistant storage stability (Patent Document 1), or Both low-temperature fixability and heat-resistant storage stability are achieved (Patent Document 2). However, when these toners are exposed to a high-temperature and high-humidity environment for a long period of time, it is difficult to ensure low-temperature fixability, gloss unevenness is observed, and image quality is deteriorated.

  Therefore, the present invention provides a toner for developing an electrostatic latent image that can ensure low-temperature fixability even when exposed to a high temperature and high humidity environment for a long period of time, suppress gloss unevenness, and obtain high image quality. The purpose is to do.

  The present inventors have conducted intensive research to solve the above problems. As a result, the cross-section of the toner base particles is not in contact with the release agent and the thread crystal structure that is not in contact with the release agent, the structure in which the crystalline resin and the release agent are in contact It has been found that the above problems can be solved by a toner for developing an electrostatic latent image containing a crystalline resin having a lamellar crystal structure, and the present invention has been completed.

  According to the present invention, there is provided an electrostatic latent image developing toner capable of ensuring low temperature fixability even when exposed to a high temperature and high humidity environment for a long period of time, suppressing uneven glossiness and obtaining high image quality. Provided.

It is a schematic diagram which shows the molecular structure of the hybrid crystalline polyester resin which is an example of the crystalline polyester resin which forms the lamellar crystal structure. FIG. 4 is a schematic view when a cross section of a toner base particle according to an embodiment of the present invention is stained with ruthenium and then observed with a secondary electron image using a TEM (transmission electron microscope).

  Embodiments of the present invention will be described below. In addition, this invention is not limited only to the following embodiment.

  In this specification, “X to Y” indicating a range means “X or more and Y or less”, and unless otherwise specified, measurement of operation and physical properties is performed at room temperature (20 to 25 ° C.) / Relative humidity 40 to 50%. Measure under RH conditions.

  The present invention is an electrostatic latent image developing toner comprising toner base particles containing at least a resin component containing a vinyl resin and a crystalline resin as main components, and a release agent, wherein the toner base particles are The crystalline resin having a thread crystal structure that is not in contact with the release agent (hereinafter, also simply referred to as “thread structure”), and the structure in which the crystalline resin and the release agent are in contact with each other (Hereinafter also simply referred to as “structure”) and the crystalline resin having a lamellar crystal structure that is not in contact with the release agent (hereinafter also simply referred to as “lamellar structure”). This is a toner for developing an electrostatic latent image. The toner of the present invention having such a configuration is excellent in that low temperature fixability can be secured even when exposed to a high temperature and high humidity environment for a long period of time, gloss unevenness can be suppressed, and high image quality can be obtained. It has the effect.

  Here, the “thread-like crystal structure (thread-like structure)” is a structure in which a crystalline resin is formed without crystallization by folding molecular chains, and is a thread-like structure composed of one or several molecular chains. Means. The “lamellar crystal structure (lamellar structure)” means a layered structure generated by crystallization by folding a crystalline resin. A detailed description of the structure will be described later.

  As described in Patent Documents 1 and 2, conventionally, by using a crystalline polyester resin as a crystalline material, it is possible to achieve both image folding resistance and heat storage stability by controlling the presence state in toner particles (Patent Document). 1) and achieving both low-temperature fixability and heat-resistant storage stability (Patent Document 2). However, it has been found that such a conventional toner causes a crystal growth of a crystalline material when it is exposed to a high temperature and high humidity environment for a long time when transported as a product or in an actual machine. For this reason, fine irregularities are generated on the toner surface, the fluidity is deteriorated, and there is a problem that the low-temperature fixability cannot be secured because the crystalline material is insufficiently melted when the toner is melted by heat. In addition, fine unevenness is generated on the toner surface due to crystal growth and the toner fluidity is deteriorated, so that the toner transportability in the developing machine becomes unstable, the toner replenishment is not stable, and the stirring and mixing in the developing machine is not stable. It will be enough. As a result, it has been found that there is a problem that the image quality is deteriorated because the charging uniformity cannot be ensured.

  On the other hand, the toner of the present invention has improved low-temperature fixability due to the presence of the crystalline resin in a specific state. The reason is considered as follows. First, the low temperature fixability is promoted by the plasticization of the crystalline resin that is compatible with the vinyl resin contained in the toner base particles according to the present invention. In particular, since the thread-like structure is elongated, the contact area with the vinyl resin is wide compared to its volume, and the effect of low-temperature fixability is likely to appear because the vinyl resin and the crystalline resin are easily compatible. it is conceivable that. Secondly, the crystalline resin crystal is rapidly melted and deformed, whereby toner deformation is promoted and low-temperature fixability is improved. This effect is exhibited by a lamellar structure having a thickness as a crystal structure or a structure in which a crystalline resin and a release agent are in contact with each other. This toner deformation is promoted more remarkably because the vinyl resin is softened by the compatibility between the thread-like structure and the vinyl resin. It is considered that the toner of the present invention can greatly improve the low-temperature fixability by these actions.

  Furthermore, in the toner base particles according to the present invention, the crystalline resin exists in three states of a thread-like structure, a structure, and a lamellar structure. Even if the toner of the present invention is exposed to a high-temperature and high-humidity environment for a long period of time, crystal growth of these three states occurs at the same time. Even if crystal growth occurs, the vinyl resin becomes soft due to the presence of a thread-like structure that is easily compatible with the vinyl resin, so that unevenness of the toner surface due to crystal growth can be mitigated. As a result, even when exposed to a high temperature and high humidity environment for a long period of time, deterioration of toner fluidity can be prevented and high image quality can be ensured.

  In the toner of the present invention, the crystalline resin crystal is rapidly melted and deformed to accelerate the deformation of the toner, and the toner deformation promotes the seepage of the release agent. However, since the release agent forms a structure with the crystalline resin, all of the release agent does not bleed out and remains partially inside the binder resin. In this way, since the release of the release agent can be appropriately controlled, the toner of the present invention does not excessively release the release agent and can suppress uneven gloss.

  In addition, the said mechanism is based on estimation and this invention is not restrict | limited to the said mechanism at all.

  Hereinafter, the electrostatic latent image developing toner of the present invention will be described in detail. The “toner” according to the present invention contains “toner base particles” as described above. The “toner base particles” are referred to as “toner particles” by adding an external additive. The “toner” refers to an aggregate of “toner particles”.

[Toner base particles]
The toner base particles according to the present invention contain a resin component including a vinyl resin and a crystalline resin as main components. The toner base particles contain a release agent and may contain other toner components such as a colorant, magnetic powder, and a charge control agent, if necessary.

<Resin components (vinyl resin and crystalline resin)>
The toner base particles according to the present invention include a resin component including a vinyl resin and a crystalline resin as main components.

≪Vinyl resin≫
The vinyl resin is a resin obtained by polymerization using at least a vinyl monomer. Specific examples of the vinyl resin include acrylic resin and styrene acrylic copolymer resin. Further, a hybrid vinyl resin in which a vinyl resin segment and a resin segment other than the vinyl resin (for example, an amorphous polyester resin segment) are chemically bonded may be included.

  Especially, as a vinyl resin, the styrene acrylic copolymer resin formed using a styrene monomer and a (meth) acrylic acid ester monomer is preferable. The vinyl resins may be used alone or in combination of two or more.

  One feature of the toner of the present invention is that the vinyl resin is the main component of the resin component contained in the toner. Here, the main component means a resin having the highest content ratio among the resin components contained in the toner. In particular, when a vinyl resin is the main component, a thread-like structure and a lamellar structure are likely to exist. Thereby, even when exposed to a high temperature and high humidity environment for a long time, a low temperature fixability can be secured, gloss unevenness can be suppressed, and a toner for developing an electrostatic latent image capable of obtaining high image quality can be obtained. When the vinyl resin is the main component, particularly when the crystalline resin is a crystalline polyester resin, the crystalline polyester resin tends to exist while maintaining the crystal structure.

  As described above, the vinyl resin is the resin having the highest content ratio among the resin components contained in the toner. The content of the vinyl resin is 50% by mass when the total resin component in the toner is 100% by mass. It is preferably 99% by mass or less, more preferably 50% by mass or more and 95% by mass or less, and even more preferably 65 to 95% by mass. When the content of the vinyl resin exceeds 50% by mass, the compatibility with the crystalline resin is suppressed to some extent and the effect of improving the charging property is increased. When the content is 65% by mass or more, the effect is further increased. There is. Further, from the viewpoint of improving low-temperature fixability, the content is preferably 99% by mass or less, and more preferably 95% by mass or less.

  The content of the vinyl resin is the content of all vinyl resins with respect to the entire resin component contained in the toner. For example, when the resin component includes a hybrid resin in which a resin other than a crystalline resin or a vinyl resin has a hybrid structure with the vinyl resin, in addition to the content of the vinyl resin as a main component contained in the toner Thus, the content of the vinyl resin segment in the hybrid resin is also included in the content of the vinyl resin.

As the vinyl monomer forming the vinyl resin, one or more selected from the following can be used.
(1) Styrene monomer styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, p-phenyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, 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 (methyl) (meth) 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 such as vinyl methyl ether and vinyl ethyl ether.
(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) Other 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 carboxyl group, a sulfonic acid group, and a phosphoric acid group, for example. Specifically, there are the following.

  Examples of the monomer having a carboxyl group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, and itaconic acid monoalkyl ester. Examples of the monomer having a sulfonic acid group include styrene sulfonic acid, allyl sulfosuccinic acid, and 2-acrylamido-2-methylpropane sulfonic acid. 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 method for producing the vinyl resin is not particularly limited, and bulk polymerization, solution using any polymerization initiator such as peroxide, persulfide, persulfate, azo compound and the like usually used for the polymerization of the above monomers. Examples of the polymerization method include polymerization, emulsion polymerization, mini-emulsion, and dispersion polymerization.

  The vinyl resin is preferably an amorphous resin having a glass transition point (Tg) of 25 to 60 ° C., and more preferably an amorphous resin having a glass transition point (Tg) of 35 to 55 ° C. . In the present specification, the glass transition point (Tg) of the resin is a value measured using “Diamond DSC” (manufactured by PerkinElmer Japan Co., Ltd.). As a measurement procedure, 3.0 mg of a measurement sample (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.

  Moreover, it is preferable that the molecular weight measured by the gel permeation chromatography (GPC) of a vinyl resin is 10,000-100,000 in a weight average molecular weight (Mw). In addition, in this specification, the molecular weight by GPC of resin is a value measured as follows. That is, using an apparatus “HLC-8120GPC” (manufactured by Tosoh Corporation) and a column “TSKguardcolumn + TSKgelSuperHZ-M3 series” (manufactured by Tosoh Corporation), while maintaining the column temperature at 40 ° C., tetrahydrofuran (THF) was used as a carrier solvent at a flow rate. Flow at 0.2 mL / min, and dissolve the measurement sample (resin) in tetrahydrofuran to a concentration of 1 mg / ml under dissolution conditions in which treatment is performed for 5 minutes using an ultrasonic disperser at room temperature. Next, a sample solution is obtained by processing with a membrane filter having a pore size of 0.2 μm, and 10 μL of this sample solution is injected into the apparatus together with the above carrier solvent, and is detected using a refractive index detector (RI detector) and measured. The molecular weight distribution of the sample is calculated using a calibration curve measured using monodisperse polystyrene standard particles. Ten polystyrenes are used for calibration curve measurement.

≪Crystalline resin≫
The crystalline resin is not particularly limited as long as the resin has crystallinity, and a conventionally known crystalline resin in this technical field can be used. Specific examples thereof include a crystalline polyester resin, a crystalline polyurethane resin, a crystalline polyurea resin, a crystalline polyamide resin, and a crystalline polyether resin. Crystalline resins can be used singly or in combination of two or more.

  Especially, it is preferable that crystalline resin contains crystalline polyester resin. Here, the “crystalline polyester resin” is obtained by a polycondensation reaction of a divalent or higher carboxylic acid (polyvalent carboxylic acid) and a derivative thereof with a divalent or higher alcohol (polyhydric alcohol) and a derivative thereof. Among known polyester resins, in differential scanning calorimetry (DSC), it refers to a resin having a clear endothermic peak rather than a stepwise endothermic change. The clear endothermic peak specifically means a peak in which the half-value width of the endothermic peak is within 15 ° C. when measured at a rate of temperature increase of 10 ° C./min in differential scanning calorimetry (DSC). To do. Examples of the polyvalent carboxylic acid derivatives include alkyl esters, acid anhydrides, and acid chlorides of polyvalent carboxylic acids. Examples of the polyhydric alcohol derivatives include ester compounds of polyhydric alcohols and hydroxycarboxylic acids.

  The polyvalent carboxylic acid is a compound containing two or more carboxyl groups in one molecule. Among these, divalent carboxylic acid is a compound containing two carboxyl groups in one molecule. For example, oxalic acid, malonic acid, succinic acid, adipic acid, pimelic acid, sebacic acid, azelaic acid, n-dodecyl Succinic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid (tetradecanedioic acid), 1,13-tridecanedicarboxylic acid, 1 Saturated aliphatic dicarboxylic acids such as 1,14-tetradecanedicarboxylic acid; cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid; unsaturated aliphatic dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, itaconic acid; phthalic acid, isophthalic acid And aromatic dicarboxylic acids such as terephthalic acid. Examples of polyvalent carboxylic acids other than divalent carboxylic acids include trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid. Examples of the derivative of the polyvalent carboxylic acid include anhydrides of these carboxylic acid compounds or alkyl esters having 1 to 3 carbon atoms. These may be used individually by 1 type and may be used in combination of 2 or more type.

  A polyhydric alcohol is a compound containing two or more hydroxyl groups in one molecule. Of these, divalent polyols (diols) are compounds containing two hydroxy groups in one molecule, such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butane. Diol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12- Mention may be made of aliphatic diols such as dodecanediol, neopentyl glycol, 1,4-butenediol. Examples of polyols other than divalent polyols include trihydric or higher polyhydric alcohols such as glycerin, pentaerythritol, trimethylolpropane, and sorbitol. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Further, it may be partially branched or cross-linked by selecting the valence of the polyvalent carboxylic acid or the valence of the polyhydric alcohol.

  Furthermore, since the crystalline resin according to the present invention has a lamellar crystal structure in the toner base particles, it preferably includes a crystalline resin having a hybrid structure. A crystalline resin having a hybrid structure (hereinafter also referred to as “hybrid crystalline resin” or “hybrid resin”, and a crystalline resin not having a plurality of segments is also simply referred to as “non-hybrid crystalline resin”) Resin in which the crystalline resin segment and the resin segment other than the crystalline resin are chemically bonded. The crystalline resin segment indicates a portion derived from a crystalline resin, and the resin segment other than the crystalline resin indicates a portion derived from a resin other than the crystalline resin. Examples of the resin other than the crystalline resin include vinyl resins such as styrene acrylic resin, urethane resins, urea resins, and polyester resins having no crystallinity. Resin segments other than the crystalline resin may be used alone or in combination of two or more.

  Among the above, the hybrid crystalline resin is a hybrid formed by chemically bonding a crystalline polyester resin segment as a crystalline resin segment and an amorphous resin segment other than a polyester resin as a resin segment other than the crystalline resin. A crystalline polyester resin is preferred. In such an embodiment, the effect of improving the low-temperature fixability by the crystalline resin is easily obtained.

  At this time, the amorphous resin segment is preferably a vinyl resin segment. That is, the hybrid crystalline resin is preferably a hybrid crystalline polyester resin in which a crystalline polyester resin segment and a vinyl resin segment are chemically bonded. Furthermore, these segments are preferably bound via both reactive monomers. Furthermore, from the viewpoint of easily forming a lamellar crystal structure, the crystalline resin is preferably a graft copolymer having a vinyl resin segment as a trunk (main chain) and a crystalline polyester resin as a branch (side chain). .

  Thus, by including the hybrid crystalline resin including the vinyl resin segment in the crystalline resin, the thickness of the lamellar crystal structure due to molecular chain folding can be increased to some extent (that is, the crystallinity can be increased). It is easy to control the domain diameter of the lamellar crystal structure described later within a preferable range. This is because the vinyl resin segment introduced into the hybrid crystalline resin has a high affinity with the vinyl resin contained in the binder resin, so that the hybrid crystalline resin is easily compatible with the vinyl resin (easily fixed). As a result, it is considered that the molecular chains of the crystalline resin are easily arranged.

  Hereinafter, a hybrid crystalline polyester resin formed by chemically bonding a crystalline polyester resin segment and a vinyl resin segment, which is preferably used in the present invention, will be described.

<Hybrid crystalline polyester resin>
-Vinyl resin segment The vinyl resin segment which comprises a hybrid crystalline polyester resin is comprised from resin obtained by superposing | polymerizing a vinyl monomer. Here, as a vinyl monomer, since what was mentioned above as a monomer which comprises a vinyl resin can be used similarly, detailed description is abbreviate | omitted here. The content of the amorphous resin segment (vinyl resin segment) other than the polyester resin in the hybrid crystalline polyester resin (hybridization rate (“HB rate” described in Examples described later; mass ratio)) is particularly limited. There is no. However, the hybridization rate of the hybrid crystalline polyester resin is more preferably in the range of 5 to 30% by mass, further preferably in the range of 5 to 20% by mass, and 5 to 15% by mass. It is particularly preferable that it is within the range. When the value of the hybridization rate in the hybrid crystalline resin is within this range, there is an advantage that it becomes easy to form a lamellar crystal structure which is a characteristic configuration of the toner according to the present invention. Compared to non-hybrid crystalline polyester resins, the hybrid crystalline polyester resin originally has crystalline resin segment portions, so that the crystalline resin segment portions are easily arranged uniformly during crystallization, and the crystalline structure is lamellar. It is easy to appear. Among the hybrid crystalline resins, those having a comb-shaped hybrid structure as shown in FIG. 1 to be described later tend to have a particularly well-arranged crystal arrangement and a lamellar crystal structure.

Crystalline polyester resin segment The crystalline polyester resin segment constituting the hybrid crystalline polyester resin is a crystalline polyester produced by polycondensation reaction of polyvalent carboxylic acid and polyhydric alcohol in the presence of a catalyst. Consists of resin. Here, specific types of the polyvalent carboxylic acid and the polyhydric alcohol are as described above, and thus detailed description thereof is omitted here.

・ Amotropic monomer “Amotropic monomer” is a monomer that binds a crystalline polyester resin segment and a vinyl resin segment, and has a hydroxy group that forms a crystalline polyester resin segment in the molecule. , A monomer having both a group selected from a carboxyl group, an epoxy group, a primary amino group and a secondary amino group and an ethylenically unsaturated group forming a vinyl resin segment. Both reactive monomers are preferably monomers having a hydroxy group or a carboxyl group and an ethylenically unsaturated group. More preferably, it is a monomer having a carboxyl group and an ethylenically unsaturated group. That is, it is preferably 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 even esters of these hydroxyalkyls (1 to 3 carbon atoms). Acrylic acid, methacrylic acid or fumaric acid is preferred from the viewpoint of reactivity. The crystalline polyester resin segment and the vinyl resin segment are bonded via the both reactive monomers.

  From the viewpoint of improving the low-temperature fixability, high-temperature offset resistance and durability of the toner, the amount of both reactive monomers used is 1 to 100 parts by mass with respect to 100 parts by mass of the total amount of vinyl monomers constituting the vinyl resin segment. 15 mass parts is preferable and 4-13 mass parts is more preferable.

-Manufacturing method of hybrid crystalline polyester resin As a method of manufacturing a hybrid crystalline polyester resin, the existing general scheme can be used. The following three methods are listed as typical methods.

(1) A crystalline polyester resin segment is polymerized in advance, the reactive polyester is reacted with the crystalline polyester resin segment, and an aromatic vinyl monomer for forming a vinyl resin segment and ( A method of forming a hybrid crystalline polyester resin by reacting a (meth) acrylate monomer;
(2) The vinyl resin segment is polymerized in advance, the reactive monomer is reacted with the vinyl resin segment, and the polyvalent carboxylic acid and polyhydric alcohol for forming the crystalline polyester resin segment are further reacted. A method of forming a crystalline polyester resin segment by
(3) A method in which a crystalline polyester resin segment and a vinyl resin segment are respectively polymerized in advance, and both are reacted with each other by reacting them with each other.

  In the present invention, any of the above production methods can be used, but the method of the above item (2) is preferred. Specifically, the polyvalent carboxylic acid and polyhydric alcohol that form the crystalline polyester resin segment, the vinyl monomer that forms the vinyl resin segment, and the both reactive monomers are mixed, and a polymerization initiator is added. It is preferable to carry out a polycondensation reaction by adding an esterification catalyst after addition polymerization of a vinyl monomer and an amphoteric monomer to form a vinyl resin segment.

  Here, as a catalyst for synthesizing the crystalline polyester resin segment, conventionally known various catalysts can be used. Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin (II) 2-ethylhexanoate, titanium alkoxides such as tetranormal butyl titanate, tetraisopropyl titanate, tetramethyl titanate, and tetrastearyl titanate. Examples of the esterification promoter include gallic acid.

  The melting point (Tc) of the crystalline resin is preferably 55 to 90 ° C, and more preferably 70 to 85 ° C. When the melting point of the crystalline resin is within the range of 55 to 90 ° C., sufficient low-temperature fixability and excellent hot offset resistance can be obtained. Note that the melting point of the crystalline resin can be controlled by the resin composition. The melting point of the crystalline resin can be measured with a differential calorimeter (DSC).

  For example, DSC-7 differential scanning calorimeter (manufactured by Perkin Elmer Japan Co., Ltd.), TAC7 / DX thermal analyzer controller (manufactured by Perkin Elmer Japan Co., Ltd.) can be used. Specifically, 4.50 mg of a sample is sealed in an aluminum pan (KIT No. 0219-0041), which is set in a sample holder of “DSC-7”, and an empty aluminum pan is used for measuring the reference. A first heating process for raising the temperature from 0 ° C. to 200 ° C. at a heating rate of 10 ° C./min, a cooling process for cooling from 200 ° C. to 0 ° C. at a cooling rate of 10 ° C./min, Data is acquired by measurement conditions (temperature increase / cooling conditions) that pass through a second temperature increase process in this order in which the temperature is increased from 0 ° C. to 200 ° C. in minutes. Based on the DSC curve obtained by this measurement, the temperature at the peak top of the endothermic peak (endothermic peak whose half-value width is within 15 ° C.) derived from the crystalline resin in the second temperature raising process is defined as the melting point.

  The weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of a crystalline polyester resin which is a preferred resin as the crystalline resin is preferably in the range of 5,000 to 100,000, more Preferably it exists in the range of 10,000-50,000. When the molecular weight is 5,000 or more, the compatibility with the vinyl resin is suppressed, and the heat resistance is further improved. When it is 100,000 or less, deterioration of low-temperature fixability can be suppressed.

  The content of the crystalline resin is preferably 1% by mass or more and less than 50% by mass, more preferably 5% by mass or more and less than 50% by mass, when the total resin component in the toner is 100% by mass. More preferably, it is 5 mass% or more and 35 mass% or less. When the content of the crystalline resin is 1% by mass or more, the effect of low-temperature fixability can be further exhibited, and when it is 5% by mass or more, the effect tends to be further increased. Further, from the viewpoint of the environmental dependency of the charge amount and the improvement of the heat-resistant storage property of the toner, the content of the crystalline resin is preferably less than 50% by mass.

  The content of the crystalline resin is the content of all the crystalline resins with respect to the entire resin component contained in the toner. For example, when the crystalline resin includes a hybrid crystalline resin, in addition to the content of the crystalline resin not having a hybrid structure contained in the toner, the crystalline resin segment in the hybrid crystalline resin The content is also included in the content of the crystalline resin.

  A method for forming a crystalline polyester resin preferable as a crystalline resin is not particularly limited, and the resin is obtained by polycondensing (esterifying) the polyvalent carboxylic acid and the polyhydric alcohol using a known esterification catalyst. Can be formed. Details of the manufacturing method will be described later.

  The resin component contained in the toner of the present invention may contain other amorphous resin such as amorphous polyester resin in addition to vinyl resin and crystalline resin. The content of the other amorphous resin is preferably 30% by mass or less with respect to the entire resin component in the toner, and the content is 0% by mass, that is, the amorphous resin is not included. It is more preferable.

  In the toner of the present invention in which the toner base particles have a thread-like structure, a structure, and a lamellar structure, it is preferable to use a hybrid crystalline polyester resin and a non-hybrid crystalline polyester resin in combination as the crystalline resin.

<Release agent>
The toner base particles according to the present invention include a release agent. Specific examples of the release agent include low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene; silicones that exhibit a softening point upon heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide ; Plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; hydrocarbon waxes such as paraffin wax, microcrystalline wax, Fischer-Tropsch wax, stearyl stearate , Behenyl behenate, butyl stearate, propyl oleate, glyceryl monostearate, glyceryl distearate, pentaerythritol tetrabehenate, diethylene glycol monostearate, Propylene glycol distearate, may be mentioned distearate diglycerides, sorbitan monostearate, ester waxes such as cholesteryl stearate and the like. These release agents can be used singly or in combination of two or more.

  When monoester waxes are used as the release agent, there is a tendency that a thread-like structure not in contact with the release agent according to the present invention is easily formed. On the other hand, when a hydrocarbon wax with few carbon chain branches and a small molecular weight distribution is used as the release agent, the structure according to the present invention tends to be easily formed. The reason for this is not clear, but due to the balance of affinity with the crystalline resin and the surrounding resin, a thread-like structure that is not in contact with the release agent according to the present invention or a structure according to the present invention is formed. I guess that. For this reason, in order to make a thread-like structure, a structure, and a lamellar structure coexist, it is preferable to use two types of different release agents in combination. For example, by using a combination of a hydrocarbon wax with few carbon chain branches and a small molecular weight distribution and monoester waxes having one ester bond, it is easy to coexist with a thread-like structure, structure, and lamellar structure. There is a tendency to become. In addition, even when a release agent is used alone, it is considered that the thread-like structure, the structure, and the lamellar structure can coexist by balancing the affinity with the crystalline resin and the surrounding resin. It is done. Specifically, for example, hydrocarbon waxes having many carbon chain branches and polyvalent ester waxes having a plurality of ester bonds having a relatively large molecular weight distribution, and functional separation of two or more functional groups by modification. The use of a release agent having a structure also facilitates the coexistence of a thread-like structure, a structure, and a lamellar structure. That is, the characteristic feature of the present invention as described above is that the cross section of the toner base particles has a crystalline resin having a thread-like structure that is not in contact with the release agent, and the crystalline resin and the release agent are in contact with each other. As one of the methods for realizing the structure that the structure and the crystalline resin having a lamellar structure that is not in contact with the release agent are present, there is a method of appropriately selecting the release agent. Can be mentioned.

  As an example, when a hydrocarbon wax having a small molecular weight distribution and a monoester wax having one ester bond are used in combination as a release agent, the ratio of the amount used is hydrocarbon wax: monoester wax = 10: It is preferable that it is 90-90: 10 (mass ratio).

  The carbon chain branching and molecular weight distribution of the hydrocarbon wax can be obtained, for example, by analyzing the width of the n-paraffin ratio and the carbon number distribution by gas chromatographic analysis.

  Here, in the present specification, the phrase “there is little carbon chain branching” specifically means that the n-paraffin ratio is 85% or more. Moreover, that there are many branches of carbon number specifically means that the n-paraffin ratio is less than 85%.

  Further, in the present specification, the molecular weight distribution of the hydrocarbon wax specifically refers to a hydrocarbon having the largest number of carbon atoms among hydrocarbons detected by gas chromatographic analysis at an area ratio of 0.1% or more. The number obtained by adding 1 to the difference between the number of carbon atoms and the number of carbon atoms of the hydrocarbon having the smallest number of carbon atoms. For example, when the number of carbons of the hydrocarbon having the largest number of carbons is 30 and the number of carbons of the hydrocarbon having the smallest number of carbons is 10, the molecular weight distribution is 21.

  Further, in the present specification, “small molecular weight distribution” means that the molecular weight distribution is 37 or less, and “large molecular weight distribution” means that the molecular weight distribution is 38 or more.

  As the releasing agent, it is preferable to use a releasing agent having a melting point of 50 to 95 ° C. from the viewpoint of reliably obtaining low-temperature fixability and releasing property of the toner. The content of the release agent in the toner is preferably 2 to 20% by mass, where the total of the resin component and the release agent in the toner is 100% by mass.

<Presence state of crystalline resin>
In the present invention, on the cross section of the toner base particles, a crystalline resin having a thread structure that is not in contact with the release agent, a structure in which the crystalline resin and the release agent are in contact, and a release agent, One of the features is that it includes a crystalline resin having a lamellar structure that is not in contact. Here, as long as the crystalline resin and the release agent are in contact with each other even at one point, they are included in the “structure” according to the present invention, and a composite of the crystalline resin and the release agent is included. means.

  FIG. 1 shows a schematic diagram of a hybrid crystalline polyester resin 10 which is an example of a crystalline polyester resin forming a lamellar crystal structure. The hybrid crystalline polyester resin 10 has a structure in which a crystalline polyester resin segment 12 is chemically bonded as a side chain to a vinyl resin segment 11 serving as a main chain. As shown in FIG. 1, the crystalline polyester resin segment 12 is bonded to the vinyl resin segment 11 in a comb shape. Such a comb-shaped structure is formed by crystallizing the crystalline polyester resin segment 12 by overlapping in a vinyl resin. As a result, a lamellar crystal structure is formed.

  In addition, although the hybrid crystalline polyester resin was demonstrated as preferable resin which forms a lamellar structure in the above, a lamellar structure is not limited to the said form. Even with only the crystalline polyester resin, an overlapping structure can be taken, and as a result, a lamellar structure can be formed.

  As a method for confirming the presence or absence of a thread-like structure, a structure, and a lamellar structure, for example, toner base particles obtained by removing external additives from toner particles are dyed by ruthenium dyeing, and then transmitted through the cross section of the toner base particles. The method of observing with a type | mold electron microscope (TEM) is mentioned.

  FIG. 2 is a schematic view when a cross-section of the toner base particles according to an embodiment of the present invention is stained with ruthenium and then observed with a secondary electron image using a TEM (transmission electron microscope). As shown in FIG. 2, the cross section of the toner base particle according to the embodiment of the present invention includes a crystalline resin 3 having a thread-like structure that is not in contact with the release agent in the vinyl resin 6 as a matrix. Domains (portions surrounded by solid lines in FIG. 2), domains of the structure 4 in which the crystalline resin 1 and the release agent 2 (portions surrounded by one-dot chain lines in FIG. 2) are in contact (intervals in FIG. 2 are And a domain of the crystalline resin 5 having a lamellar structure that is not in contact with the release agent (portion surrounded by a dotted line having a wide interval in FIG. 2).

  In contrast, a whiter contrast portion is determined as a release agent. Since the resin component other than the release agent has many double bond portions and is dyed with ruthenium tetroxide, the release agent portion can be distinguished from the resin portion other than the release agent. That is, as shown in FIG. 2, the release agent is dyed lightest by ruthenium dyeing, and then the crystalline resin having a thread-like structure, the crystalline resin forming the structure, and the crystalline resin having a lamellar structure Is dyed darkly, and vinyl resin is dyed darkest.

  Specifically, the cross section of the toner base particles can be observed by, for example, the following observation method.

<Method for observing cross section of toner base particles>
Observation conditions Device: Transmission electron microscope “JSM-2000FX” (manufactured by JEOL Ltd.)
Sample: A section of toner base particles stained with ruthenium tetroxide (RuO ₄ ) (section thickness: 60 to 100 nm)
Acceleration voltage: 30 kV
Magnification: 10,000 times, bright field image.

-Method for preparing a section of dyed toner base particles 3 parts by weight of the prepared toner was dispersed in 35 parts by weight of a 0.2% by weight aqueous solution of polyoxyethyl phenyl ether, followed by ultrasonication (manufactured by Nippon Seiki Co., Ltd.). , US-1200T) at 25 ° C. for 5 minutes to remove the external additive from the toner surface to obtain toner base particles for TEM observation.

1 to 2 mg of the obtained toner base particles are put in a 10 ml sample bottle and treated under the ruthenium tetroxide (RuO ₄ ) vapor dyeing conditions shown below, followed by photocurable resin “D-800” (JEOL Ltd.) In the company) and UV-cured to form blocks. Next, an ultrathin sample having a thickness of 60 to 100 nm is cut out from the above block using a microtome equipped with diamond teeth.

-Ruthenium tetroxide dyeing | staining conditions Dyeing is performed using the vacuum electron dyeing | staining apparatus VSC1R1 (made by Filgen Corporation). In accordance with the apparatus procedure, a sublimation chamber containing ruthenium tetroxide was installed in the staining apparatus body, and after the prepared ultrathin section was introduced into the staining chamber, the staining conditions with ruthenium tetroxide were room temperature (24-25 ° C.), Staining is performed under conditions of a concentration of 3 (300 Pa) and a time of 10 minutes.

-Observation of crystal structure It observes with a transmission electron microscope "JSM-7401F" (made by JEOL Ltd.) within 24 hours after dyeing | staining.

  When a cross section of 100 arbitrary toner base particles is observed by the above-described method, 60% (60) or more of the toner base particles having a thread-like structure, a structure, and a lamellar structure are present in the cross section. 80% (80 pieces) or more is preferable. Within such a range, a toner capable of ensuring low-temperature fixability, suppressing gloss unevenness and obtaining high image quality even when exposed to a high-temperature and high-humidity environment for a long period of time can be obtained.

≪Structure≫
The shape of the structure is not particularly limited. However, the average domain diameter of the structure is preferably 100 nm or more and 3000 nm or less, more preferably 150 nm or more and 2700 nm or less, and further preferably 200 nm or more and 2500 nm or less. When the average domain diameter of the structure is 100 nm or more, the toner is sufficiently deformed during heat melting, and low-temperature fixability can be secured. On the other hand, when the average domain diameter of the structure is 3000 nm or less, excessive bleeding of the release agent can be suppressed, and a difference occurs in the remaining amount of the release agent between the image portion and the non-image portion in the fixing member. It is difficult to suppress uneven glossiness on the surface to be printed next.

≪Filamentary structure≫
The average major axis of the filamentous domain is preferably 100 nm or more and 2500 nm or less, more preferably 150 nm or more and 2200 nm or less, and further preferably 200 nm or more and 2000 nm or less. If the average major axis of the domain of the thread-like structure is 100 nm or more, the compatibility of the crystalline resin having the thread-like structure with the binder resin proceeds appropriately, and the inside of the toner is caused by domain growth when stored in a high-temperature and high-humidity environment. By preventing the binder resin from following the deformation that occurs, it is possible to prevent unevenness on the toner surface, and high image quality can be obtained. On the other hand, if the average major axis of the domains of the thread-like structure is 2500 nm or less, heating the toner in the fixing step can sufficiently melt the thread-like structure and ensure low-temperature fixability.

  The average minor axis of the domains of the thread-like structure is preferably 5 nm or more and 1500 nm or less, more preferably 10 nm or more and 1000 nm or less, and further preferably 10 nm or more and 500 nm or less.

  The average major axis and the average minor axis of the domains of the thread-like structure can be controlled by, for example, the amount and composition of the crystalline resin, and when a toner is prepared using a crystalline resin dispersion, The dispersion diameter of the crystalline resin in the crystalline resin dispersion can be controlled. When a crystalline resin having a structure not having a hybrid structure (non-hybrid crystalline polyester resin) is used, a tendency to form a thread-like structure more easily is observed. Furthermore, when non-hybrid crystalline polyester resin is used, the amount of non-hybrid crystalline polyester resin added is increased, or the dispersion diameter of non-hybrid crystalline polyester resin in the non-hybrid crystalline polyester resin dispersion is increased. Then, there exists a tendency for a thread-like structure to become large.

≪Lamellar structure≫
The average domain diameter of the lamellar structure is preferably 50 nm or more and 2500 nm or less, more preferably 70 nm or more and 2200 nm or less, and further preferably 100 nm or more and 2000 nm or less. By setting the average domain diameter to 50 nm or more, the toner is sufficiently deformed at the time of heat melting, and low temperature fixability can be secured. On the other hand, by setting the average domain diameter to 2500 nm or less, unevenness generated on the toner surface when the toner is stored in a high temperature and high humidity environment can be reduced, and high image quality can be obtained.

  The average domain diameter of the lamellar structure can be controlled by, for example, the amount and composition of the crystalline resin. When a toner is prepared using a crystalline resin dispersion, the crystalline resin dispersion It can be controlled by the dispersion diameter of the crystalline resin therein. When a resin having a hybrid structure (hybrid crystalline polyester resin) is used as the crystalline resin, it tends to form a lamellar structure more easily. Furthermore, when a hybrid crystalline polyester resin is used, increasing the amount of the hybrid crystalline polyester resin added, or increasing the dispersion diameter of the hybrid crystalline polyester resin in the hybrid crystalline polyester resin dispersion, Tend to be larger.

  In this specification, “domain” refers to a structure having an island-like phase having a closed interface (boundary between phases) in a matrix that is a continuous phase, and its length. Is defined as the domain diameter.

≪Method for measuring the size of filamentous structures, structures and lamellar structures (domain diameter, average major axis, average minor axis) ≫
The size (domain diameter, average major axis, average minor axis) of the thread-like structure, the structure, and the lamellar structure can be calculated using commercially available image processing software for an image observed using a TEM.

  The size (domain diameter) of the structure and the lamellar structure in the cross section of the toner base particles is calculated as a horizontal ferret diameter (FERE H). Specifically, a cross section of the toner base particles produced in the same manner as described above was taken with a transmission electron microscope JEM-2000FX (manufactured by JEOL Ltd.) at an acceleration voltage of 80 kV at a magnification of 50,000 times, and a photographic image was scanned. And measuring the horizontal ferret diameter (FERE H) of the structure and the lamellar structure using an image processing analyzer LUZEX AP (manufactured by Nireco Corporation). Similarly, the long diameter (major axis) of the filamentous structure is the maximum length (MX LNG) instead of the horizontal ferret diameter (FERE H), and the short diameter (short axis) is the horizontal ferret diameter (FERE H). Instead of each, the width (BR′DTH) is measured. The width (BR′DTH) is the shortest distance between two straight lines when an image is sandwiched between two straight lines parallel to the maximum length (MX LNG). The average domain diameter, the average major axis, and the average minor axis are calculated as arithmetic average values for all of the toner base particles in which the thread-like structure, the structure, and the lamellar structure are observed.

≪Cross-sectional area ratio of structure, thread structure, and release agent≫
The ratio of the cross-sectional area of the thread structure to the cross-sectional area of the toner base particles is A, the ratio of the cross-sectional area of the structure to the cross-sectional area of the toner base particles is B, and the ratio of the cross-sectional area of the lamellar structure to the cross-sectional area of the toner base particles is B / (A + B + C + D) is preferably from 0.30 to 0.70, where D is the ratio of the cross-sectional area of the release agent not forming the structure to the cross-sectional area of C and toner base particles. More preferably, it is 0.35-0.65. If B / (A + B + C + D) is 0.30 or more, excessive bleeding of the release agent can be suppressed, and a difference in the remaining amount of the release agent between the image portion and the non-image portion in the fixing member is unlikely to occur. Further, gloss unevenness can be suppressed on the surface to be printed next. On the other hand, if it is 0.70 or less, the cross-sectional area ratio of the thread-like structure or the lamellar structure becomes a suitable range, and when the toner is stored in a high-temperature and high-humidity environment, the unevenness generated on the toner surface can be reduced. High image quality can be obtained.

  The above A, B, C, and D can be measured by, for example, the same apparatus and conditions as the above-described method for measuring the size of the thread-like structure, the structure, and the lamellar structure, and the horizontal ferret diameter (FERE H ) Can be measured using “area AREA” of an image processing analysis apparatus LUZEX AP (manufactured by Nireco Corporation). Each cross-sectional area is an area surrounded by an outer contour (for example, a thread-shaped structure is an area surrounded by a solid line in FIG. 2, a structure is an area surrounded by a dotted line with a narrow interval in FIG. 2, and a lamellar structure is a figure. 2), a region surrounded by a dotted line with a wide interval is measured. This cross-sectional area ratio is also calculated as an arithmetic average value of the 100 toner base particles in which both the thread-like structure, the structure and the lamellar structure are observed.

<Colorant>
In the toner according to the present invention, the toner base particles may contain a colorant. Examples of the colorant include carbon black, black iron oxide, dye, and pigment.

  Examples of carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. Examples of black iron oxide include magnetite, hematite, and iron iron trioxide.

  Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95 and the like.

  Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 48: 3, 53: 1, 57: 1, 81: 4, 122, 139, 144, 149, 150, 166, 177, 178, 222, 238, 269, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment yellow 14, 17, 74, 93, 94, 138, 155, 156, 158, 180, 185, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 60, and the like.

  The colorant for obtaining the toner of each color can be used singly or in combination of two or more for each color. The content ratio of the colorant in the toner base particles is preferably 1 to 10% by mass.

<Charge control agent>
The toner base particles according to the present invention may contain a charge control agent. Examples of the charge control agent include metal complexes of salicylic acid derivatives such as zinc and aluminum (salicylic acid metal complexes), calixarene compounds, organic boron compounds, and fluorine-containing quaternary ammonium salt compounds.

  The content of the charge control agent is usually preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the resin component in the toner.

<External additive>
The toner base particles according to the present invention can be used as toner particles as they are, but from the viewpoint of improving the charging performance, fluidity, and cleaning properties of the toner, known inorganic fine particles and organic fine particles are formed on the surface thereof. It is preferable to add particles such as a lubricant and the like as external additives. Various external additives may be used in combination. Examples of the particles include inorganic oxide fine particles such as silica fine particles, alumina fine particles, and titania fine particles, inorganic stearate compound fine particles such as aluminum stearate fine particles and zinc stearate fine particles, strontium titanate fine particles, and zinc titanate fine particles. And inorganic titanic acid compound fine particles. Moreover, as a lubricant, a salt such as zinc stearate, aluminum, copper, magnesium, calcium, a salt of zinc oleate, manganese, iron, copper, magnesium, etc., zinc palmitate, copper, magnesium, calcium, etc. And salts of higher fatty acids such as salts, zinc of linoleic acid, salts of calcium, etc., zinc of ricinoleic acid, salts of calcium, etc. These external additives may be subjected to surface treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil, or the like from the viewpoint of heat-resistant storage stability and environmental stability.

  The amount of these external additives added is preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the toner base particles.

<Glass transition point of toner>
The glass transition point (Tg) of the toner of the present invention is preferably 25 to 65 ° C, more preferably 35 to 55 ° C. When the glass transition point of the toner of the present invention is in the above range, a toner having sufficient low-temperature fixing property and heat-resistant storage property can be obtained. The glass transition point of the toner is measured in the same manner as described above except that the toner is used as a measurement sample.

<Toner particle size>
The average particle diameter of the toner according to the present invention is preferably 3 to 8 μm, and more preferably 5 to 8 μm, for example, on a volume basis median diameter. This average particle diameter can be controlled by the concentration of the flocculant used during production, the amount of organic solvent added, the fusing time, the composition of the resin component, and the like. When the volume-based median diameter is in the above range, a very small dot image of 1200 dpi level can be faithfully reproduced. The volume-based median diameter of the toner is measured and calculated using a measuring apparatus in which a computer system equipped with data processing software “Software V3.51” is connected to “Multisizer 3” (manufactured by Beckman Coulter, Inc.). Is. Specifically, 0.02 g of a measurement sample (toner) was added to 20 mL of a surfactant solution (for example, a surfactant obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing toner particles). The solution was added to the solution and allowed to acclimate, and then ultrasonic dispersion was performed for 1 minute to prepare a toner dispersion. This toner dispersion was placed in “ISOTONII” (manufactured by Beckman Coulter, Inc.) in the sample stand. Pipette into beaker until display concentration of measuring device is 8%. Here, a reproducible measurement value can be obtained by setting this concentration range. In the measuring apparatus, the measurement particle count is set to 25000, the aperture diameter is set to 100 μm, the frequency range is calculated by dividing the measurement range of 2 to 60 μm into 256, and the volume integrated fraction is 50% from the larger one. The particle diameter of is a volume-based median diameter.

<Average circularity of toner>
In the toner according to the present invention, the individual toner particles constituting the toner preferably have an average circularity of 0.920 to 1.000 from the viewpoint of stability of charging characteristics and low-temperature fixability. More preferably, it is from 950 to 0.995. When the average circularity is within the above range, the individual toner particles are less likely to be crushed, the contamination of the frictional charge imparting member is suppressed, the toner chargeability is stabilized, and the image quality of the formed image is high. It will be a thing. The average circularity of the toner is a value measured using “FPIA-2100” (manufactured by Sysmex Corporation). Specifically, the measurement sample (toner) was blended with an aqueous solution containing a surfactant, subjected to ultrasonic dispersion treatment for 1 minute to disperse, and then subjected to measurement conditions using “FPIA-2100” (manufactured by Sysmex Corporation). In the HPF (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. It is a value calculated by adding and dividing by the total number of toner particles. If the number of HPF detections is in the above range, reproducibility can be obtained.

Circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)
[Toner Production Method]
Examples of the method for producing the toner of the present invention include a pulverization method, a miniemulsion method, an emulsion aggregation method, and other known methods. However, the characteristic feature of the present invention as described above is that the cross section of the toner base particles has a crystalline resin having a thread-like structure that is not in contact with the release agent, and the crystalline resin and the release agent are in contact with each other. As a manufacturing method for realizing a configuration in which there is a structure having a lamellar structure that is not in contact with the release agent, the particle size and shape of the toner base particles are controlled. It is preferable that it is a manufacturing method which has the process of cooling after performing.

  By performing this cooling step, it is possible to prevent aggregation of crystallized substances (for example, crystalline resins and mold release agents), so it is assumed that it is easy to create a coexistence state of the thread-like structure, the structure, and the lamellar structure. ing. In the cooling step, it is preferable to perform rapid cooling. The rapid cooling is based on the temperature before cooling and the target temperature after cooling, but as a guideline, the cooling rate is 8 ° C./min or more. By performing this cooling step (preferably rapid cooling) after controlling the particle size and shape of the toner base particles, a crystalline resin having a thread-like structure that is not in contact with the release agent and exists independently The structure in which the crystalline resin is in contact with the release agent and the crystalline resin having a lamellar structure that is not in contact with the release agent and exists independently can be more easily maintained. Further, the emulsion aggregation method is more preferable because the toner base particles can be easily reduced in size from the viewpoint of production cost and production stability. Therefore, when the emulsion aggregation method is used, it is more preferable to perform cooling (preferably rapid cooling) after shape control is performed by aggregating until a desired particle diameter is achieved and further fusing between resin particles.

  The emulsion aggregation method is a dispersion of resin particles (hereinafter also referred to as “resin particles”) produced by emulsification, and dispersion of colorant particles (hereinafter also referred to as “colorant particles”) as necessary. In this method, toner base particles are produced by mixing with a liquid, agglomerating until a desired particle diameter is obtained, and further controlling the shape by fusing resin particles. Here, the resin particles may contain a mold release agent and, if necessary, a charge control agent.

  Hereinafter, the emulsion aggregation method which is a preferable production method will be described.

<Emulsion aggregation method>
As described above, in the emulsion aggregation method, a dispersion of resin particles dispersed by a surfactant or a dispersion stabilizer is mixed with a dispersion of constituent components of toner base particles such as colorant particles, if necessary. In this method, toner particles are aggregated by adding an aggregating agent to a desired particle diameter, and thereafter or simultaneously with aggregation, fusion between resin fine particles is performed, and shape control is performed to form toner base particles.

  For example, an aqueous dispersion of crystalline resin particles, an aqueous dispersion of release resin-containing vinyl resin particles, and an aqueous dispersion of colorant particles are mixed, and the respective particles are aggregated and then fused. Thus, the toner base particles according to the present invention can be obtained. Further, instead of the aqueous dispersion of release agent-containing vinyl resin particles, the aqueous dispersion of release agent particles and the aqueous dispersion of vinyl resin particles may be separately prepared and mixed. An aqueous dispersion of particles or an aqueous dispersion of crystalline resin and release agent-containing vinyl resin particles can also be used.

  When the toner base particles are manufactured by an emulsion aggregation method, for example, a manufacturing method including the following steps is employed. Here, in the following examples, the vinyl resin particles contain a release agent, the crystalline resin particles are crystalline polyester resin particles, and the toner base particles contain a colorant. The technical scope of the present invention is not limited to these forms.

(A) Step of preparing a dispersion of crystalline polyester resin particles in an aqueous medium (b) Step of preparing a dispersion containing vinyl resin particles containing a release agent in an aqueous medium (c) An aqueous medium (D) mixing the dispersion of the crystalline polyester resin particles, the dispersion of the release agent-containing vinyl resin particles, and the dispersion of the colorant particles. (E) A step of agglomerating and fusing the crystalline polyester resin particles, the release agent-containing vinyl resin particles, and the colorant particles. (F) The shape of the toner base particles after aging by heat energy. (G) Cooling step for cooling the dispersion of the toner base particles After the step (g), further, (h-1) separating the toner base particles from the aqueous dispersion of the toner base particles. , Toner base particles Cleaning to remove the surfactant and the like, and drying and drying the washed toner base particles; (h-2) external additive processing step of adding an external additive to the dried toner base particles The toner particles can be produced by performing as necessary.

<< (a) Step of preparing a dispersion of crystalline polyester resin particles >>
This step preferably comprises the following steps:
(A-1) Crystalline polyester resin synthesis step (A-2) Crystalline polyester resin particle dispersion preparation step.

(A-1) Crystalline polyester resin synthesis step The method for producing the crystalline polyester resin is not particularly limited, and can be produced by a general polyester polymerization method in which a polyvalent carboxylic acid and a polyhydric alcohol are reacted. For example, direct polycondensation, transesterification, and the like are separately used depending on the type of monomer. As the catalyst that can be used in the production of the crystalline polyester resin, the same catalyst as the catalyst for synthesizing the above-described crystalline polyester resin segment is used, and thus detailed description thereof is omitted here.

  The use ratio of the polyhydric alcohol to the polycarboxylic acid is such that the equivalent ratio [OH] / [COOH] of the hydroxy group [OH] of the polyhydric alcohol to the carboxyl group [COOH] of the polyhydric carboxylic acid is 1.5. /1/1/1.5 is preferable, and 1.2 / 1 to 1 / 1.2 is more preferable. Further, the polymerization temperature and the polymerization time are not particularly limited, and the inside of the reaction system may be decompressed as necessary during the polymerization.

(A-2) Crystalline polyester resin particle dispersion preparation step The crystalline polyester resin particle dispersion preparation step is a step of dispersing the crystalline polyester resin synthesized above in the form of fine particles in an aqueous medium. This is a step of preparing a dispersion.

  As a method for preparing the crystalline polyester resin particle dispersion, for example, (i) a method in which a crystalline polyester resin is dispersed in an aqueous medium without using a solvent, or (ii) the crystalline polyester resin is treated with ethyl acetate, Examples include a method of dissolving in a solvent such as methyl ethyl ketone and toluene to form a solution, emulsifying and dispersing the solution in an aqueous medium using a disperser, and then performing a solvent removal treatment (solvent removal step).

  The “aqueous medium” used in the above (i) and (ii) means a medium containing at least 50% by mass of water, and examples of components other than water include organic solvents that dissolve in water. Examples thereof include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, dimethylformamide, methyl cellosolve, and tetrahydrofuran. Of these, it is preferable to use an alcohol-based organic solvent such as methanol, ethanol, isopropanol, or butanol, which is an organic solvent that does not dissolve the resin. More preferably, only water is used as the aqueous medium.

  Further, in the aqueous medium, amine or ammonia may be dissolved in order to stably emulsify in the aqueous phase and facilitate the emulsification, and in order to improve the dispersion stability of the oil droplets, the surface activity An agent or resin fine particles may be added.

  As the surfactant, known anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants can be used. As the surfactant, it is preferable to use an anionic surfactant because it is excellent in dispersion stability of oil droplets by the crystalline polyester resin and stability against temperature change is obtained. Examples of the anionic surfactant include higher fatty acid salts such as sodium oleate; alkyl aryl sulfonates such as sodium dodecylbenzene sulfonate; alkyl sulfate salts such as sodium lauryl sulfate (sodium dodecyl sulfate); polyoxyethylene Polyoxyethylene alkyl ether sulfates such as sodium lauryl ether sulfate and polyethoxyethylene sodium lauryl ether sulfate (polyoxyethylene (2) sodium dodecyl ether sulfate); polyoxyethylene alkylaryl such as polyoxyethylene nonylphenyl ether sodium sulfate Ether sulfates; sodium monooctylsulfosuccinate, sodium dioctylsulfosuccinate, polyoxyethylene Alkyl sulfosuccinate ester salts such as Lil sodium sulfosuccinate, and derivatives thereof, and the like. The above surfactants can be used singly or in combination of two or more as desired.

  Examples of the resin fine particles for improving dispersion stability include polymethyl methacrylate resin fine particles, polystyrene resin fine particles, and polystyrene-acrylonitrile resin fine particles.

  In the above (ii), the synthesized crystalline polyester resin is dissolved in an organic solvent to prepare a crystalline polyester resin solution. Thereafter, the crystalline polyester resin solution is emulsified and dispersed in an aqueous medium to form oil droplets made of the crystalline polyester solution. In this process, oil prepared by the phase inversion emulsification method can be used to uniformly disperse the oil droplets by changing the stability of the carboxyl group of the polyester. It is excellent in that it is not dispersed. In the “phase inversion emulsification method”, a resin is dissolved in an organic solvent to obtain a resin solution, a neutralization step in which a neutralizer is added to the resin solution, and the neutralized resin solution is dispersed in an aqueous system. By passing through an emulsification step of emulsifying and dispersing in a medium to obtain a resin emulsion, and a desolvation step of removing the organic solvent from the resin emulsion, a dispersion of resin fine particles is obtained.

  The dispersion treatment (emulsification dispersion) in the above (i) and (ii) can be performed using mechanical energy, and the disperser is not particularly limited, and is a wet emulsification disperser, a homogenizer, a low speed Examples thereof include a shearing disperser, a high-speed shearing disperser, a friction disperser, a high-pressure jet disperser, an ultrasonic disperser, and a high-pressure impact disperser.

  The particle size of the crystalline polyester resin particles in the dispersion can be controlled by adjusting the amount of neutralizing agent added, that is, adjusting the degree of neutralization. There is a tendency that the smaller the neutralizer addition amount, that is, the lower the neutralization degree, the larger the particle size of the resin particles in the dispersion.

  In the method (ii), the organic solvent is distilled off from the formed oil droplets to produce crystalline polyester resin particles, and a dispersion of crystalline polyester resin particles is prepared. Specifically, the organic solvent is preferably distilled off in a state where the degree of vacuum is in the range of 400 to 50000 Pa and at a temperature in the range of 30 to 50 ° C.

  The particle size of the crystalline polyester resin particles is preferably in the range of 30 to 500 nm, for example, on a volume basis median diameter. The particle size of the crystalline polyester resin particles can be measured by a dynamic light scattering method using, for example, “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.). The dispersion diameter of the oil droplets can be controlled by the magnitude of mechanical energy during emulsification dispersion.

  The content of the crystalline polyester resin particles in the crystalline polyester resin particle dispersion is preferably in the range of 10 to 50% by mass with respect to 100% by mass of the dispersion, and more preferably in the range of 15 to 40% by mass. preferable. Within such a range, the spread of the particle size distribution can be suppressed and the toner characteristics can be improved.

<< (b) Step of Preparing a Dispersion Containing Vinyl Resin Particles Containing Release Agent (Release Agent-Containing Vinyl Resin Particle Dispersion >>
This step is a step of synthesizing a vinyl resin constituting the toner base particles, dispersing the vinyl resin in the form of particles in an aqueous medium, and adding a release agent to prepare a dispersion of vinyl resin particles. .

  Specific examples of the vinyl resin polymerization method are as described above.

  As a method for dispersing the vinyl resin in the aqueous medium, a method (I) of forming vinyl resin particles from a monomer for obtaining the vinyl resin and preparing an aqueous dispersion of the vinyl resin particles, An oil phase liquid is prepared by dissolving or dispersing in an organic solvent (solvent), and the oil phase liquid is dispersed in an aqueous medium by phase inversion emulsification or the like, and oil droplets in a state of being controlled to a desired particle diameter are formed. Examples thereof include a method (II) for removing the organic solvent (solvent) after the formation. In these methods (I) and (II), it is preferable to add a release agent together with the vinyl resin monomer (or vinyl resin).

  In the method (I), first, a monomer for obtaining a vinyl resin is added to an aqueous medium together with a polymerization initiator and polymerized to obtain basic particles. Next, a radical polymerizable monomer and a polymerization initiator for obtaining a vinyl resin are added to the dispersion in which the basic particles are dispersed, and the radical polymerizable monomer is seed-polymerized on the basic particles. It is preferable to use a technique. When adding the radical polymerizable monomer and the polymerization initiator, it is preferable to add a release agent at the same time.

  At this time, a water-soluble polymerization initiator can be used as the polymerization initiator. As the water-soluble polymerization initiator, for example, a water-soluble radical polymerization initiator such as potassium persulfate or ammonium persulfate can be suitably used.

  Moreover, the chain transfer agent generally used can be used for the seed polymerization reaction system for obtaining a vinyl resin particle for the purpose of adjusting the molecular weight of a vinyl resin. As the chain transfer agent, octyl mercaptan, dodecyl mercaptan, t-dodecyl mercaptan, n-octyl-3-mercaptopropionate, stearyl-3-mercaptopropionate, styrene dimer and the like can be used.

  In the method (II), as the organic solvent (solvent) used for the preparation of the oil phase liquid, as described above, from the viewpoint of easy removal after the formation of oil droplets, the boiling point is low and water is used. Those having low solubility in water are preferred, and specific examples include methyl acetate, ethyl acetate, methyl ethyl ketone, isopropyl alcohol, methyl isobutyl ketone, toluene, xylene and the like. These can be used alone or in combination of two or more.

  The amount of the organic solvent (solvent) used (when two or more types are used, the total amount used) is usually 10 to 500 parts by weight, preferably 100 to 450 parts by weight, more preferably 100 parts by weight of the vinyl resin. 200 to 400 parts by mass.

  The amount of the aqueous medium used is preferably 50 to 2,000 parts by mass and more preferably 100 to 1,000 parts by mass with respect to 100 parts by mass of the oil phase liquid. By making the usage-amount of an aqueous medium into said range, an oil phase liquid can be emulsified and dispersed to a desired particle size in an aqueous medium.

  Similarly to the above, a dispersion stabilizer may be dissolved in the aqueous medium, and a surfactant or resin fine particles may be added for the purpose of improving the dispersion stability of the oil droplets. Good. Such emulsification and dispersion of the oil phase liquid can be performed using mechanical energy in the same manner as described above, and the disperser for performing the emulsification and dispersion is not particularly limited. -2) can be used.

  The removal of the organic solvent after the formation of the oil droplets is performed by gradually heating the whole dispersion liquid in which the vinyl resin particles are dispersed in the aqueous medium in a stirring state and giving strong stirring in a certain temperature range. It can be carried out by an operation such as desolvation. Alternatively, it can be removed while reducing the pressure using an apparatus such as an evaporator.

  In the method (II), an aqueous dispersion (release agent particle dispersion) of a release agent prepared separately is added to the obtained dispersion containing vinyl resin particles, and the release agent-containing vinyl resin particle dispersion is added. Prepare the solution.

  As the aqueous medium, the surfactant, the resin fine particles and the like used in the aqueous dispersion of the release agent, the same ones as described in the above (A-2) can be used. Further, the release agent can be dispersed using mechanical energy, and such a disperser is not particularly limited, and is the same as described in (A-2) above. Things can be used.

  The content of the release agent particles in the release agent particle dispersion is preferably in the range of 10 to 50% by mass, and more preferably in the range of 15 to 40% by mass. Within such a range, effects of preventing hot offset and ensuring separability can be obtained.

  The dispersion diameter of the vinyl resin particles (oil droplets) in the vinyl resin particle dispersion prepared by the method (I) or (II) is a volume-based median diameter (volume average particle diameter), preferably 60 to 1000 nm. 80 to 500 nm is more preferable. The dispersion diameter of the oil droplets can be controlled by the magnitude of mechanical energy during emulsification dispersion. The dispersion diameter of the vinyl resin particles in the vinyl resin particle dispersion can be measured by a dynamic light scattering method using, for example, “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.).

  Moreover, it is preferable to make content of the vinyl resin particle in a vinyl resin particle dispersion into the range of 5-50 mass%, and the range of 10-30 mass% is more preferable. Within such a range, the spread of the particle size distribution can be suppressed and the toner characteristics can be improved.

  Here, the vinyl resin particles may be composite particles formed of a plurality of layers having two or more layers made of resins having different compositions.

<< (c) Colorant particle dispersion preparation process >>
The colorant particle dispersion preparation step is a step of preparing a dispersion of colorant particles by dispersing a colorant in the form of particles in an aqueous medium. The colorant dispersion treatment is preferably performed in a state where the surfactant concentration in the aqueous medium is not less than the critical micelle concentration (CMC) since the colorant is uniformly dispersed.

  The aqueous medium is as described in (A-2) above, and a surfactant or resin fine particles may be added to the aqueous medium for the purpose of improving dispersion stability. Further, the colorant can be dispersed using mechanical energy, and such a disperser is not particularly limited, and those described in (A-2) above may be used. it can.

  The dispersion diameter of the colorant particles in the colorant particle dispersion is preferably in the range of 10 to 300 nm in terms of volume-based median diameter. The dispersion diameter of the colorant particles in this colorant particle dispersion can be measured by a dynamic light scattering method using, for example, “Microtrack UPA-150” (manufactured by Nikkiso Co., Ltd.).

  The content of the colorant in the colorant particle dispersion is preferably in the range of 10 to 50% by mass, and more preferably in the range of 15 to 40% by mass. Within such a range, there is an effect of ensuring color reproducibility.

≪ (d) Liquid mixture preparation process and (e) Aggregation / fusion process≫
In the mixed liquid preparation step, each particle dispersion prepared in the steps (a) and (b) is mixed. At this time, if necessary, the colorant dispersion prepared in the step (c) may be further mixed. The order of addition of the respective dispersions is not particularly limited, and the conditions such as the stirring speed are not particularly limited. In this step, in addition to the above-described dispersions, a charge control agent and other constituents of the toner base particles may be mixed as necessary.

  The agglomeration / fusion step performed after or simultaneously with the mixed liquid preparation step includes the above-described crystalline polyester resin particles, release agent-containing vinyl resin particles, and, if necessary, colorant particles, charging in an aqueous medium. This is a step of aggregating the control agent and other constituent components of the toner base particles, and simultaneously aggregating the particles to obtain toner base particles.

  As a specific method for aggregating and fusing the crystalline polyester resin particles, the release agent-containing vinyl resin particles, and the colorant particles used as necessary, the coagulant in the aqueous medium is set to a critical aggregation concentration or more. And then heating to a temperature not lower than the glass transition point of the resin particles and not higher than the melting peak temperature of the mixture, thereby producing crystalline polyester resin particles, release agent-containing vinyl resin particles and colorant particles. As the salting out of the particles proceeds, the fusion is proceeded in parallel. And when it grows to a desired particle diameter, the method of adding a coagulation terminator and stopping particle growth and continuing heating in order to control a particle shape as needed is mentioned. In this method, the time allowed to stand after adding the flocculant is shortened as quickly as possible, and immediately heated to a temperature above the glass transition point of these resin particles and below the melting peak temperature of these mixtures. Is preferred. The reason for this is not clear, but depending on the standing time after salting out, the aggregation state of the particles may fluctuate and the particle size distribution may become unstable, and the surface properties of the fused particles may vary. This is because there is concern about the occurrence. The time until this temperature rise is usually preferably within 30 minutes, more preferably within 10 minutes. Moreover, it is preferable that it is 1 degree-C / min or more as a temperature increase rate. The upper limit of the heating rate is not particularly specified, but is preferably 15 ° C./min or less from the viewpoint of suppressing the generation of coarse particles due to rapid progress of fusion. Furthermore, after the reaction system reaches a temperature equal to or higher than the glass transition point, it is important to continue the fusion by maintaining the temperature of the reaction system for a certain time. Thereby, the growth and fusion of the toner base particles can be effectively advanced, and the durability of the finally obtained toner particles can be improved. In the present invention, in the aggregation / fusion process, the dispersion of the crystalline polyester resin particles and the dispersion of the release agent-containing vinyl resin particles may be divided into the first stage and the second stage.

  The flocculant used in the agglomeration / fusion step is not particularly limited, but a material selected from metal salts is preferably used. Examples of the metal salt include monovalent metal salts such as alkali metals such as sodium, potassium and lithium; divalent metal salts such as calcium, magnesium, manganese and copper; and trivalent metal salts such as iron and aluminum. Can be mentioned. Specific metal salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Among these, agglomerates in a smaller amount. It is particularly preferable to use a divalent metal salt. These can be used alone or in combination of two or more. The toner base particles obtained in this agglomeration / fusion step preferably have a volume-based median diameter (volume average particle diameter) in the range of 2 to 9 μm, more preferably 4 to 7 μm. Within range. The volume-based median diameter of the toner base particles can be measured by, for example, “Particle Size Distribution Measuring Device Multisizer 3” (manufactured by Beckman Coulter, Inc.).

  When obtaining a toner having a core-shell structure, an aqueous dispersion of a resin that forms a shell portion is further added in this step, and the single-layered resin particles (core particles) obtained above are added. The resin forming the shell part on the surface is aggregated and fused. Thereby, toner base particles having a core-shell structure are obtained (shell forming step). At this time, subsequent to the shelling step, the agglomeration and fusion of the shell to the surface of the core particles are further strengthened, and the reaction system is further heat-treated until the particles have a desired shape, that is, (f) described later. A maturing step may be performed. The heat treatment of the reaction system may be performed until the average circularity of the toner base particles having a core-shell structure falls within the above average circularity range.

≪ (f) Aging process≫
Although the shape of the toner base particles in the toner can be made uniform to some extent by controlling the heating temperature in the above aggregation / fusion process, it is preferable to go through an aging step in order to further make the shape uniform. In this aging step, by controlling the heating temperature and the heating time, the surface of the toner base particles having a uniform particle diameter and a narrow distribution is controlled to have a smooth and uniform shape. Specifically, the heating temperature is lowered in the agglomeration / fusion process to suppress the progress of fusion between the resin particles to promote homogenization, and in this aging process, the heating temperature is lowered and time is reduced. The toner base particles are controlled to be longer so that the toner particles have a desired average circularity, that is, a surface having a uniform shape. As described above, the average circularity is preferably 0.920 to 1.000.

≪ (g) Cooling process≫
After the toner base particles have a desired average circularity, the dispersion is cooled. At this time, by controlling the cooling conditions, the existence state (for example, domain diameter and shape of each material) of the material constituting each toner base particle in the toner base particle is changed. When the cooling rate is decreased, for example, aggregation of the crystallized substance is promoted, and crystal growth may occur. On the other hand, when the cooling rate is increased, for example, the aggregation of the crystallized substance is suppressed, and the structure in the aging process tends to be maintained without promoting the crystallization. As described above, 8 ° C./min or more is preferable as a guideline for the temperature lowering rate at which the coexistence state of the thread-like structure, the structure, and the lamellar structure, which is a feature of the present invention, can be easily made.

  The cooling method is not particularly limited, and examples thereof include a method of cooling by introducing a refrigerant from the outside of the reaction vessel, and a method of cooling by directly introducing cold water into the reaction system.

≪ (h-1) Cleaning and drying process≫
The washing / drying step can be performed by employing various known methods. That is, after aging to the desired average circularity in the aging step and cooling, solid-liquid separation and washing are performed using a known device such as a centrifuge. The washing treatment is a washing treatment until the electric conductivity of the filtrate reaches, for example, a level of 5 to 10 μS / cm.

  In the drying step, the toner base particles that have been subjected to the cleaning process are subjected to a drying process. In the drying, after the organic solvent is removed by drying under reduced pressure as necessary, moisture and a trace amount of the organic solvent are further removed by a known drying device such as a flash jet dryer and a fluidized bed drying device. The drying temperature may be in a range where the toner base particles are not fused. The amount of water contained in the dried toner base particles is preferably 5% by mass or less, more preferably 2% by mass or less.

  In addition, when the dried toner base particles are aggregated with a weak interparticle attractive force, a crushing process may be performed.

<< (h-2) External additive treatment process >>
This external additive treatment step is a step of preparing toner particles by adding and mixing external additives as necessary to the dried toner base particles. Since the types and preferred addition amounts of the external additives are as described above, the description thereof is omitted here. Examples of the method for adding the external additive include a dry method in which the external additive is added in powder form to the dried toner base particles. Examples of the mixing device include mechanical mixing devices such as a Henschel mixer and a coffee mill. It is done.

[Developer for electrostatic latent image development]
The toner of the present invention can be used as a magnetic or non-magnetic one-component developer, but may be mixed with a carrier and used as a two-component developer. When the toner is used as a two-component developer, the carrier includes magnetic particles made of conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead. In particular, ferrite particles are preferable. Further, as the carrier, a coated carrier in which the surface of magnetic particles is coated with a coating agent such as a resin, a dispersion type carrier in which a magnetic fine powder is dispersed in a binder resin, or the like may be used.

  The volume-based median diameter of the carrier is preferably 20 to 100 μm, and more preferably 25 to 80 μm. The volume-based median diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by Sympathic) equipped with a wet disperser.

[Electrophotographic image forming method]
The electrostatic latent image developing toner and developer according to the present invention can be used in various known electrophotographic image forming methods. For example, it can be used in a monochrome image forming method or a full color image forming method. In the full-color image forming method, four types of color developing devices for yellow, magenta, cyan, and black, and one electrostatic latent image carrier (also referred to as “electrophotographic photosensitive member” or simply “photosensitive member”) Any image, such as a four-cycle image forming method comprising: a color developing device for each color and an image forming unit having an electrostatic latent image carrier for each color. A formation method can also be used.

  Specifically, as the electrophotographic image forming method, the electrostatic latent image developing developer according to the present invention is used, for example, charged on the electrostatic latent image carrier with a charging device (charging process), By developing an electrostatic latent image (exposure process) electrostatically formed by image exposure by charging toner with a carrier in the developer for developing an electrostatic latent image according to the present invention in a developing device. A toner image is obtained by developing the image (development process). Then, the toner image is transferred to a recording medium (transfer process), and then the toner image transferred onto the recording medium is fixed on the recording medium by a contact heating type fixing process (fixing process). can get.

  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples.

[Production of crystalline resin]
<Preparation of Crystalline Resin (Crystalline Polyester Resin) (cn-1)>
45 parts by mass of ethylene glycol, 135 parts by mass of 1,4-butanediol, and 330 parts by mass of adipic acid were placed in a three-necked flask, and 0.7 parts by mass of dibutyltin oxide and 0.4 parts by mass of hydroquinone were added as catalysts. The reaction was carried out at 160 ° C. for 5 hours in a nitrogen gas atmosphere. Furthermore, it was made to react at 160 degreeC until resin of desired melting | fusing point was obtained at 8.3 kPa, and crystalline resin (cn-1) was obtained. When this crystalline resin (cn-1) was measured by DSC at a temperature rising rate of 10 ° C./min, it had a clear peak, the peak top temperature was 78 ° C., and the peak half-width was 10 ° C. there were. Moreover, the weight average molecular weight of crystalline resin (cn-1) was 24,800.

<Preparation of Crystalline Resin (Crystalline Polyester Resin) (cn-2) to (cn-3)>
The crystalline resin (cn-) was prepared in the same manner as in <Preparation of Crystalline Resin (cn-1)> except that the types and amounts of the added polycarboxylic acid and polyhydric alcohol were changed as shown in Table 1 below. 2) to (cn-3) were prepared.

<Synthesis of Hybrid Crystalline Polyester Resin (cm-1)>
A raw material monomer of an addition polymerization resin (styrene acrylic resin: StAc1) segment having the following composition and containing both reactive monomers and a radical polymerization initiator were placed in a dropping funnel.

Styrene 58 parts by mass n-butyl acrylate 20 parts by mass Acrylic acid 3.4 parts by mass Polymerization initiator (di-t-butyl peroxide) 7 parts by mass.

  In addition, the raw material monomer of the following polycondensation resin (crystalline polyester resin: CPEs1) segment is put into a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, and heated to 170 ° C. to dissolve. I let you.

Ethylene glycol 45 parts by mass 1,4-butanediol 135 parts by mass Adipic acid 330 parts by mass.

  Next, while stirring the contents of the flask, the raw material monomer of the addition polymerization resin (StAc1) was dropped over 90 minutes, and after aging for 60 minutes, an unreacted addition polymerization system was performed under reduced pressure (8 kPa). The raw material monomer of the resin was removed. The amount of monomer removed at this time was very small with respect to the raw material monomer ratio of the resin.

Thereafter, 0.8 part by mass of Ti (OBu) ₄ was added as an esterification catalyst, heated to 235 ° C., reacted for 5 hours under normal pressure (101.3 kPa), and further reduced under reduced pressure (8 kPa) to 1 Time reaction was performed.

  Next, after cooling to 200 ° C., a hybrid crystalline polyester resin (cm−1) was obtained by reacting under reduced pressure (20 kPa) for 1 hour. The content (HB ratio) of the resin (StAc) segment other than CPEs with respect to 100% by mass of the total amount of the hybrid crystalline polyester resin (cm-1) is 13.8% by mass, and the obtained resin is the StAc segment. Is a main chain, and a crystalline polyester resin (CPEs) segment is grafted as a side chain. The hybrid crystalline polyester resin (cm-1) had a weight average molecular weight (Mw) of 27,800 and a melting point (Tc) of 76 ° C.

<Synthesis of Hybrid Crystalline Polyester Resin (cm-2, cm-3)>
In the synthesis of the hybrid crystalline polyester resin (cm-1), the above <hybrid crystalline polyester resin (cm-1) except that the types and amounts of polyhydric alcohol and polyvalent carboxylic acid were changed as shown in Table 2 below. Preparation of hybrid crystalline polyester resins (cm−2) to (cm−3) in the same manner as described above.

  The properties of the crystalline resins cn-1 to cn-3 are shown in Table 1 below, and the properties of the hybrid crystalline polyester resins cm-1 to cm-3 are shown in Table 2 below.

<Preparation of Crystalline Resin (Crystalline Polyester Resin) Particle Dispersion (CA-1)>
300 parts by mass of the crystalline resin (cn-1) was melted and transferred to the emulsification disperser “Cabitron CD1010” (manufactured by Eurotech Co., Ltd.) at a transfer rate of 100 parts by mass per minute. Simultaneously with the transfer of the crystalline resin (cn-1) in the molten state, dilute ammonia having a concentration of 0.37% by mass obtained by diluting reagent ammonia water with ion-exchanged water in an aqueous solvent tank with respect to the emulsifier / disperser. Water was transferred at a transfer rate of 0.1 liters per minute while heating to 100 ° C. with a heat exchanger. Then, the emulsification disperser was operated under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² to prepare a crystalline resin particle dispersion (CA-1). The diluted ammonia water was added so that the neutralization degree was 45%. The dispersion diameter of the crystalline resin particles in the crystalline resin particle dispersion (CA-1) was 203 nm in terms of volume-based median diameter.

<Preparation of Crystalline Resin Particle Dispersions (CA-2) to (CA-5), (CB-1) to (CB-5)>
The crystalline resin particle dispersion (in the same manner as <Preparation of crystalline resin particle dispersion (CA-1)> except that the type and neutralization degree of the crystalline resin were changed as shown in Table 3 below. CA-2) to (CA-5) and (CB-1) to (CB-5) were prepared.

  In addition, the neutralization degree converted the amount of ammonia used for neutralization into the amount of KOH used for neutralization, and the value calculated by the following formula (1) was defined as the degree of neutralization (unit:%). .

<Preparation of vinyl resin particle dispersion (VD-1)>
A reaction vessel equipped with a stirrer, temperature sensor, cooling tube, and nitrogen introducing device was charged with a solution prepared by dissolving 0.65 parts by mass of sodium dodecyl sulfate in 95 parts by mass of ion-exchanged water, and a stirring speed of 230 rpm under a nitrogen stream. The internal temperature was raised to 80 ° C. with stirring. After the temperature increase, a solution in which 0.47 parts by mass of potassium persulfate was dissolved in 18 parts by mass of ion-exchanged water was added, the liquid temperature was again adjusted to 80 ° C., and the following monomer mixture 1 was added dropwise over 1 hour, and then 80 Polymerization was carried out by stirring at 2 ° C. for 2 hours to prepare resin particles [1H]:
<Monomer mixture 1>
Styrene 30 parts by mass n-butyl acrylate 7 parts by mass Methacrylic acid 2 parts by mass.

The following monomer mixture 2 was heated to 90 ° C. while stirring, and hydrocarbon wax W-1 (paraffin wax, n-paraffin ratio: 90%, molecular weight distribution: 26, melting point: 75 ° C. as a release agent in this mixture. ) 56 parts by mass and monoester wax W-2 (behenyl behenate, melting point: 73 ° C.) 56 parts by mass were dissolved to prepare a monomer mixture 3 containing a release agent:
<Monomer mixture 2>
Styrene 280 parts by mass n-butyl acrylate 78 parts by mass n-octyl-3-mercaptopropionate 5.5 parts by mass.

A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device was charged with a solution in which 5 parts by mass of polyoxyethylene (2) sodium dodecyl ether sulfate was dissolved in 780 parts by mass of ion-exchanged water, and 98 ° C. After heating, the monomer mixture 3 containing the above releasing agent was added, and the mixture was dispersed and dispersed for 1 hour by a mechanical disperser “CLEARMIX (registered trademark)” (manufactured by M Technique Co., Ltd.) having a circulation path. A dispersion containing particles (oil droplets) was prepared. To this dispersion, 39 parts by mass (in terms of solid content) of resin particles [1H] and 1000 parts by mass of ion-exchanged water were added, and a stirrer set at 90 rpm stirring and an internal temperature of 82 ° C., a temperature sensor, The reactor was charged with a cooling tube and a nitrogen introducing device. Next, an initiator solution in which 4.55 parts by mass of potassium persulfate was dissolved in 87 parts by mass of ion-exchanged water was added to this dispersion, and the system was heated and stirred at 82 ° C. for 1 hour for polymerization. This gave resin particles [1HM]. Furthermore, a solution prepared by dissolving 6.07 parts by mass of potassium persulfate in 120 parts by mass of ion-exchanged water was added, and the temperature was 82 ° C.
Styrene 205 parts by weight n-butyl acrylate 100 parts by weight Methacrylic acid 18 parts by weight n-octyl-3-mercaptopropionate A monomer mixed solution consisting of 4.4 parts by weight was added dropwise over 1 hour. After completion of the dropwise addition, polymerization was carried out by heating and stirring for 2 hours, followed by cooling to 28 ° C. to obtain a vinyl resin particle dispersion (VD-1) containing a release agent and vinyl resin particles.

  The dispersion diameter of the vinyl resin particles in the obtained vinyl resin particle dispersion (VD-1) is 230 nm in terms of volume-based median diameter, the glass transition point (Tg) is 44 ° C., and the weight average molecular weight (Mw ) Was 34,000.

<Preparation of vinyl resin particle dispersions (VD-2) to (VD-10)>
<Production of vinyl resin particle dispersion (VD-1)> except that the amount of release agent added in the production method of vinyl resin particle dispersion (VD-1) was changed as shown in Table 4 below. In the same manner, vinyl resin particle dispersions (VD-2) to (VD-10) were produced.

<Preparation of colorant particle dispersion>
90 parts by mass of sodium dodecyl sulfate was stirred and dissolved in 1600 parts by mass of ion-exchanged water. While stirring this solution, 420 parts by mass of carbon black “Regal (registered trademark) 330R” (manufactured by Cabot) was gradually added, and then a stirring device “Claremix (registered trademark)” (manufactured by M Technique Co., Ltd.). ) Was used for dispersion treatment to prepare a colorant particle dispersion having dispersed colorant particles. When the dispersion diameter of the colorant particles in this dispersion was measured using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), the volume-based median diameter was 117 nm.

[Production of toner]
<Preparation of Toner 1>
(Aggregation / fusion process)
In a 5-liter stainless steel reactor equipped with a stirrer, a cooling tube, and a temperature sensor, 30 parts by mass (in terms of solid content) of “crystalline resin particle dispersion (CA-2)” and “crystalline resin particle dispersion” "Liquid (CB-1)" 30 parts by mass (solid content conversion), "Vinyl resin particle dispersion (VD-1)" 380 parts by mass (solid content conversion), and "Colorant particle dispersion" 40 masses. Part (solid content conversion) was added, and 380 parts by mass of ion-exchanged water was added, and the pH was adjusted to 10 using a 5 (mol / liter) aqueous sodium hydroxide solution while stirring. Subsequently, a magnesium chloride aqueous solution in which 40 parts by mass of magnesium chloride hexahydrate was dissolved in 40 parts by mass of ion-exchanged water was added dropwise over 10 minutes with stirring. The internal temperature was raised to 80 ° C., the particle size was measured using Multisizer 3 (Beckman Coulter, Inc., aperture diameter; 50 μm), and when the volume-based median diameter reached 6.0 μm, A sodium chloride aqueous solution in which 160 parts by mass of sodium chloride was dissolved in 640 parts by mass of ion-exchanged water was added. Furthermore, using the flow particle image measuring device “FPIA-2100” (manufactured by Sysmex Corporation) with continuous heating and stirring, when the average circularity reaches 0.960, the internal temperature is reduced at a cooling rate of 15 ° C./min. The mixture was cooled to 50 ° C. and then cooled to 25 ° C. at a cooling rate of 8 ° C./min to obtain a dispersion liquid of “toner base particle 1”.

(Washing and drying)
The dispersion of toner base particles 1 produced in the aggregation / fusion process was subjected to solid-liquid separation using a basket-type centrifuge to form a wet cake of toner base particles. The wet cake was washed with ion exchange water at 35 ° C. until the electrical conductivity of the filtrate reached 5 μS / cm with the basket-type centrifuge, and then transferred to “flash jet dryer (manufactured by Seishin Enterprise Co., Ltd.)” The toner was dried until the water content became 0.5% by mass to prepare “toner base particles 1”.

(External additive treatment process)
1 part by weight of hydrophobic silica (number average primary particle diameter = 12 nm) and 0.3 part by weight of hydrophobic titania (number average primary particle diameter = 20 nm) are added to 100 parts by weight of the above “toner base particle 1”. The toner 1 was prepared by mixing with a Henschel mixer.

<Preparation of Toner 2 to Toner 20>
Toners 2 to 20 were prepared in the same manner as in <Preparation of Toner 1> except that the types and addition amounts of the crystalline resin dispersion and vinyl resin dispersion to be added were changed as shown in Table 5 below. The toner 18 is a toner that does not contain a non-hybrid crystalline polyester resin as a resin component. The toner 20 is a toner that does not contain a hybrid crystalline polyester resin as a resin component.

  Toners 1 to 20 had a particle size in the range of 5.8 to 6.5 μm and an average circularity in the range of 0.958 to 0.965.

<Production of developer>
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) are put into a high-speed mixer equipped with stirring blades and stirred and mixed at 120 ° C. for 30 minutes. A resin coat layer was formed on the surface of the ferrite core by the action of mechanical impact force to obtain a carrier having a volume-based median diameter of 40 μm.

  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. Toners 1 to 32 are added to the carrier so that the toner concentration is 7% by mass, and the toner is introduced into a micro-type V-type mixer (Tsujii Chemical Co., Ltd.), mixed at a rotational speed of 45 rpm for 30 minutes, and developed. 1-20 were produced.

[Evaluation]
<Section observation of toner base particles>
According to the observation method shown below, cross sections of the produced toner 1 to toner 20 were observed. No thread-like structure was observed in the toner 18 as a comparative example, no structure was observed in the toner 19, and no lamellar structure was observed in the toner 20. In the toners 1 to 17, three types of structures, a thread-like structure and a lamellar structure were confirmed on the cross section of 60% (60) or more of the 100 toner base particles. Further, in the cross sections of the toners 1 to 17, no crystalline resin having a structure other than the thread-like structure, the structure, and the lamellar structure was observed. Table 7 below shows the measurement results of the domain diameter of the structure and the lamellar structure, the average long diameter of the filamentous structure, and the cross-sectional area ratio (B / (A + B + C + D)) of the structure.

<Method for observing toner base particle cross section>
Observation conditions Device: Transmission electron microscope “JSM-7401F” (manufactured by JEOL Ltd.)
Sample: A section of toner base particles stained with ruthenium tetroxide (RuO ₄ ) (section thickness: 60 to 100 nm)
Acceleration voltage: 30 kV
Magnification: 10,000 times Observation conditions: transmission electron detector, bright field image.

-Method for preparing section of dyed toner base particles 3 parts by weight of the prepared toner 1 and 35 parts by weight of 0.2% by weight aqueous solution of polyoxyethyl phenyl ether were dispersed and then subjected to ultrasonic (Nippon Seiki Co., Ltd.) Manufactured by US-1200T) for 5 minutes at 25 ° C., the external additive was removed from the toner surface, and toner base particles for TEM observation were obtained. For other toners, the external additive was removed in the same manner as described above to obtain toner base particles for TEM observation.

1 to 2 mg of the obtained toner base particles are put in a 10 ml sample bottle and treated under the ruthenium tetroxide (RuO ₄ ) vapor dyeing conditions shown below, followed by photocurable resin “D-800” (JEOL Ltd.) In the company) and UV-cured to form blocks. Next, an ultrathin sample having a thickness of 60 to 100 nm was cut out from the above block using a microtome equipped with diamond teeth.

  Thereafter, the cut-out sample was again processed and stained under the following processing conditions.

-Ruthenium tetroxide dyeing | staining conditions The ruthenium tetroxide process was performed using the vacuum electron dyeing | staining apparatus VSC1R1 (made by Philgen Corporation). According to the apparatus procedure, a sublimation chamber containing ruthenium tetroxide is installed in the main body of the staining apparatus, and after introducing the toner or the ultrathin section into the staining chamber, the staining condition with ruthenium tetroxide is room temperature (24 to 25 ° C.), Dyeing was performed under conditions of a concentration of 3 (300 Pa) and a time of 10 minutes.

-Observation of crystal structure It observed with the transmission electron microscope "JSM-7401F" (made by JEOL Ltd.) within 24 hours after dyeing | staining.

-Measuring method of size of filamentous structure, structure, lamellar structure (domain diameter, average major axis) The size of the structure and lamellar structure (domain diameter) in the cross section of the toner base particle is the horizontal ferret diameter (FERE). H). Specifically, a cross section of the toner base particles produced in the same manner as described above was taken with a transmission electron microscope JEM-2000FX (manufactured by JEOL Ltd.) at an acceleration voltage of 80 kV at a magnification of 50,000 times, and a photographic image was scanned. And the horizontal ferret diameter (FERE H) of the structure and the lamellar structure was measured using an image processing analysis apparatus LUZEX AP (manufactured by Nireco Corporation). Similarly, the maximum length (MX LNG) of the long diameter (major axis) of the thread-like structure was measured instead of the horizontal ferret diameter (FERE H). The average domain diameter of the structure and the lamellar structure and the average major axis of the thread-like structure are calculated as an arithmetic average value of all the toners in which the structure, the thread-like structure, and the lamellar structure are observed. did.

-Cross-sectional area ratio of structure, thread-like structure, lamellar-like structure, and release agent It measured by the method similar to the measuring method of the magnitude | size of a structure, a thread-like structure, and a lamellar structure mentioned above. The cross-sectional area ratio A of the thread-like structure to the cross-sectional area of the toner base particles, the cross-sectional area ratio B of the structural body to the cross-sectional area of the toner base particles, the cross-sectional area ratio C of the lamellar structure to the cross-sectional area of the toner base particles, and the toner base particles The cross-sectional area ratio D of the release agent that does not form a structure with respect to the cross-sectional area was measured using “Area AREA” of LUZEX AP (manufactured by Nireco Corporation). The area is a region surrounded by the outer contour (the structure is a region surrounded by a dotted line with a narrow interval in FIG. 2, the thread-like structure is a region surrounded by a solid line in FIG. 2, and the lamellar structure has a wide interval in FIG. The area surrounded by a dotted line) was measured. This cross-sectional area ratio was also calculated as an arithmetic average value for the 100 toner base particles in which both the thread-like structure, the structure, and the lamellar structure were observed.

Image formation method Image evaluation was modified so that the fixing temperature, toner adhesion amount, and system speed can be freely set in a commercially available color multifunction peripheral “bizhub PRESS (registered trademark) C6000 (manufactured by Konica Minolta Co., Ltd.)”. A modified machine A was produced. The developing device of the modified machine A was evaluated by sequentially loading the toners 1 to 20 prepared above and the developer.

・ Low temperature fixability (under offset)
The evaluation is based on a fixing experiment in which a solid image with a toner adhesion amount of 8 g / m ² is fixed in an environment of normal temperature and normal humidity (temperature 20 ° C., humidity 50% RH). The temperature was set low and the temperature of the upper fixing belt was changed from 110 ° C. in increments of 5 ° C. to 20 ° C. repeatedly. This experiment was performed at a fixing speed of 300 mm / sec. Evaluation was performed using an A4-size NPI fine 127.9 g / m ² (manufactured by Nippon Paper Industries Co., Ltd.).

  Under-offset refers to an image defect that peels from a transfer material such as recording paper because the toner layer is not sufficiently melted by the applied heat when passing through the fixing device. When an image was formed by the above method, the lower limit fixing temperature of the upper fixing belt where no under-offset occurred was evaluated and used as an index for low temperature fixability. The lower this fixing minimum temperature is, the better the fixing property is, and a temperature lower than 140 ° C. is considered acceptable.

  This low-temperature fixability was evaluated for both the toner stored for 24 hours (HH storage) at a temperature of 50 ° C. and a relative humidity of 80% RH, and the toner before HH storage.

Gloss unevenness Evaluation was performed by setting the toner adhesion amount to 8 g / m ² in an environment of normal temperature and normal humidity (temperature 20 ° C., relative humidity 50% RH). A fixing experiment was conducted in which the first half of the image of one recording medium was a solid image and half was not printed, and the second half of the image of one recording medium was fixed as a solid image. The temperature of the lower fixing roller was set to be 20 ° C. lower than that of the upper fixing belt, and the temperature of the upper fixing belt was the above-described under-offset temperature + 20 ° C. This experiment was performed at a fixing speed of 300 mm / sec. Evaluation was performed using an A3 size POD gloss coat 128.0 g / m ² (manufactured by Oji Paper Co., Ltd.), and the gloss difference between the first half of the image and the second half of the image was visually ranked.

  The gloss unevenness was evaluated visually for both a toner stored at 50 ° C. and a relative humidity of 80% RH for 24 hours (HH storage) and a toner before HH storage, and evaluated based on the following rank. Evaluation was performed at n = 2, and an average value of evaluation was calculated. Ranks 2.5 to 5 are practical.

Rank 1: Clearly there is a gloss difference and cannot be used Rank 2: When the image is tilted, the gloss difference is recognized Rank 3: The gloss difference is recognized only slightly, but it can be used somehow Rank 4: Gloss difference Is almost unrecognized Rank 5: There is no gloss difference.

Image density stability The toner is filled in a bottle, and the toner bottle is left for 12 hours in an environment of high temperature and high humidity (temperature: 40 ° C., relative humidity: 60% RH). 1000 images were printed and the density was measured every 100 sheets to compare the difference between the maximum and minimum. The concentration measurement was performed by measuring the Bk concentration using a fluorescence spectral densitometer FD-7 (manufactured by Konica Minolta Co., Ltd.). If the density difference is 3.5 or less, it is practical.

  The properties of the toners of Examples and Comparative Examples are shown in Table 6 below, and the evaluation results of the toners are shown in Table 7 below. In addition, the ratio in Table 6 represents a ratio when the total mass of the resin component and the release agent is 100% by mass.

<Discussion>
As is apparent from Table 7 above, the main component of the resin component contained in the toner is vinyl resin, and the crystallinity having a thread-like structure that is not in contact with the release agent when the cross section of the toner base particles is observed. Toners 1 to 17 in which a resin, a structure formed by contacting a crystalline resin and a release agent, and a crystalline resin having a lamellar structure not in contact with the release agent coexist It has been found that, even after storage in a high temperature and high humidity environment, low temperature fixability can be ensured, gloss unevenness can be suppressed, and high image quality can be obtained.

  On the other hand, toners 18 to 20 as comparative examples are formed in toner base particles by contacting a crystalline resin having a thread-like structure that is not in contact with the release agent, or a crystalline resin and the release agent. None of the structure and the crystalline resin having a lamellar structure that is not in contact with the release agent. It has been found that such toners 18 to 20 have problems in at least one of low-temperature fixability after storage in a high-temperature and high-humidity environment, gloss unevenness, and image density stability, and are not at a practical level.

1 crystalline resin,
2 release agents,
3 crystalline resin having a thread-like structure not in contact with the release agent,
4 structures,
5 crystalline resin having a lamellar structure that is not in contact with the release agent;
6 Vinyl resin,
10 Hybrid crystalline polyester resin,
11 Vinyl resin segment,
12 Crystalline polyester resin segment.

Claims (8)

A toner for developing an electrostatic latent image, comprising toner base particles containing a resin component containing at least a vinyl resin and a crystalline resin as main components, and a release agent,
The toner base particles are:
The crystalline resin having a thread crystal structure that is not in contact with the release agent;
A structure in which the crystalline resin and the release agent are in contact; and the crystalline resin having a lamellar crystal structure that is not in contact with the release agent;
Only including,
The ratio of the cross-sectional area of the thread-like structure to the cross-sectional area of the toner base particles is A,
The ratio of the cross-sectional area of the structure to the cross-sectional area of the toner base particles is B,
The ratio of the cross-sectional area of the lamellar structure to the cross-sectional area of the toner base particles is C,
B / (A + B + C + D) is 0.35 to 0.65, where D is the ratio of the cross-sectional area of the release agent not forming the structure to the cross-sectional area of the toner base particles.
The content of the crystalline resin is 1% by mass or more and less than 50% by mass when the total resin component in the toner is 100% by mass,
The toner for developing an electrostatic latent image , wherein the content of the release agent in the toner is 2 to 20% by mass, where the total of the resin component and the release agent in the toner is 100% by mass .   The electrostatic latent image developing toner according to claim 1, wherein the crystalline resin is a crystalline polyester resin.   The electrostatic latent image developing toner according to claim 1, wherein an average major axis of the domains of the filamentous crystal structure is 200 nm or more and 2000 nm or less.   The toner for developing an electrostatic latent image according to claim 1, wherein an average domain diameter of the structure is 200 nm or more and 2500 nm or less.   The toner for developing an electrostatic latent image according to any one of claims 1 to 4, wherein an average domain diameter of the lamellar crystal structure is 100 nm or more and 2000 nm or less.   6. The electrostatic latent image developing according to claim 1, wherein the crystalline resin includes a hybrid crystalline polyester resin in which a crystalline polyester resin segment and a vinyl resin segment are chemically bonded. toner. The said mold release agent contains the hydrocarbon wax whose n-paraffin rate is 85% or more and molecular weight distribution is 37 or less, and monoester wax of any one of Claims 1-6. Toner for electrostatic latent image development. A method for producing a toner for developing an electrostatic latent image according to any one of claims 1 to 7,
Mixing an aqueous dispersion of crystalline resin particles and an aqueous dispersion of vinyl resin particles containing a release agent,
A method for producing a toner for developing an electrostatic latent image, comprising aggregating and fusing the crystalline resin particles and the vinyl resin particles.