JP2016133669A - Toner for electrostatic latent image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide means that can suppress a reduction in image density and the occurrence of fogging and enable stable image formation for a toner for electrostatic latent image development containing both a crystalline resin and an amorphous resin as a binder resin constituting toner base particles.SOLUTION: There is provided a toner for electrostatic latent image development containing toner base particles having a domain-matrix structure in which a domain phase including a crystalline resin is dispersed in a matrix phase including an amorphous resin, and external additive particles, where vinyl crosslinked resin particles having a number average particle diameter of 30 to 300 nm are used as the external additive particles.SELECTED DRAWING: None

Description

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

  2. Description of the Related Art Conventionally, in an electrophotographic image forming method in which a visible image is formed by electrophotography, a toner image formed by an electrostatic latent image developing toner (hereinafter also simply referred to as “toner”) on a transfer medium such as paper. As a fixing method, a heat roller fixing system in which a transfer medium on which a toner image is formed is fixed by passing between a heating roller and a pressure roller is widely used. In order to ensure the fixability in this heat roller fixing system, that is, the adhesion of the toner to the transfer medium such as paper, the heating roller needs a high heat capacity.

  However, in recent years, from the viewpoint of global warming prevention measures, there has been an increasing demand for energy saving for electrophotographic image forming apparatuses, and therefore, electrophotographic image formation that employs a heat roller fixing method in particular. In the apparatus, a technique for reducing the amount of heat required for fixing a toner image, that is, a technique for lowering the fixing temperature is being studied. In order to lower the toner fixing temperature, it is necessary to lower the melting temperature and melt viscosity of the binder resin constituting the toner base particles. However, if the glass transition point and molecular weight of the binder resin are lowered in order to lower the melting temperature and melt viscosity of the binder resin, new problems arise, such as poor heat-resistant storage stability of the toner or occurrence of high temperature offset.

  As a technique for solving this problem, a technique for improving low-temperature fixability of toner by using a combination of a crystalline resin and an amorphous resin as a binder resin constituting the toner base particles has been proposed.

  On the other hand, it has also been proposed to improve the chargeability, developability, and transferability by adding resin particles having a high gel fraction by crosslinking as an external additive (Patent Document 1).

JP 2004-163612 A

  As described above, the low-temperature fixability can be improved by using a crystalline resin in combination with an amorphous resin as the binder resin constituting the toner base particles. However, according to the study by the present inventors, it has been found that there is a problem that it is difficult to form a stable image, for example, the image density is lowered or fog is caused by using a crystalline resin together.

  The present invention has been made in consideration of the above-described circumstances, and is for electrostatic latent image development in which a crystalline resin and an amorphous resin are used in combination as a binder resin constituting toner base particles. An object of the present invention is to provide means capable of suppressing a decrease in image strength and occurrence of fogging in a toner and enabling stable image formation.

  The present inventors have conducted intensive studies in view of the above problems. As a result, it has been found that the above problem can be solved by constituting a toner using toner base particles having a so-called domain matrix structure in combination with vinyl-based crosslinked resin particles having a predetermined particle size as external additive particles. The present invention has been completed.

  That is, according to one aspect of the present invention, the toner base particles having a domain matrix structure in which a domain phase containing a crystalline resin is dispersed in a matrix phase containing an amorphous resin, and external additive particles are included. An electrostatic latent image developing toner is provided. The toner according to this embodiment is characterized in that the external additive particles include vinyl-based crosslinked resin particles having a number average particle diameter of 30 to 300 nm.

  According to the present invention, in the toner for developing an electrostatic latent image in which a crystalline resin and an amorphous resin are used in combination as a binder resin constituting the toner base particles, a reduction in image strength and occurrence of fog are suppressed. Thus, a technology that enables stable image formation is provided.

  Hereinafter, embodiments for carrying out the present invention will be described in detail.

<Toner>
The toner according to an embodiment of the present invention includes toner base particles and external additive particles. The toner base particles have a domain matrix structure in which a domain phase containing a crystalline resin is dispersed in a matrix phase containing an amorphous resin. The external additive particles include vinyl-based crosslinked resin particles having a number average particle diameter of 30 to 300 nm. According to the toner according to the present invention having such a configuration, it is possible to suppress a decrease in image density and occurrence of fogging and to enable stable image formation. Although the mechanism by which such an effect is manifested is not completely clear, it is estimated as follows.

  That is, when inorganic fine particles such as conventional silica fine particles are used as external additive particles, these inorganic fine particles are interposed between the resins at the toner interface, resulting in a decrease in the adhesion between the resin and the inorganic fine particles. It is considered that the image intensity is lowered. On the other hand, with the configuration according to the present invention, the vinyl-based crosslinked resin particles used as the external additive particles are entangled with the amorphous resin and the crystalline resin as the binder resin, and are further crosslinked. As a result, the strength of the toner interface can be improved. Also, the hardness of the image surface can be improved by the filler effect of the external additive particles. These results are considered to contribute to the prevention of a decrease in image intensity.

  Further, in the conventional toner, it is conceivable that the strength of the toner is decreased because the interface of the toner base particles and the crystalline resin having relatively low strength are united in the toner. On the other hand, by setting it as the structure which concerns on this invention, coalescence of crystalline resins as mentioned above can also be suppressed by presence of vinyl-type crosslinked resin particle. Moreover, since the entanglement between the vinyl-based crosslinked resin particles and the crystalline resin also partially occurs, the adhesion at the vinyl-based crosslinked resin particle-crystalline resin interface is also increased. As a result, it is considered that it contributes to prevention of a decrease in image intensity.

  Furthermore, in the conventional toner, due to the large specific gravity of the external additive particles, the external additive particles are buried, and the binder resin fine particles are also buried. It is thought that the decrease was caused. On the other hand, by using the vinyl-based crosslinked resin particles according to the present invention as the external additive particles, the specific gravity is relatively small, and the burying is suppressed by crosslinking. Furthermore, since the vinyl-based crosslinked resin particles themselves have a charge imparting performance, it is possible to prevent a decrease in chargeability after the endurance of the toner, and as a result, even after endurance in a high temperature and high humidity environment. Can effectively suppress the occurrence of fogging.

  Hereinafter, the components of the toner according to the present invention will be described in detail.

(Toner base particles)
The toner base particles according to the present invention have the above-described domain matrix structure, and as a constituent component thereof, at least a binder resin is contained, and if necessary, a colorant, a magnetic powder, a release agent, Other toner components such as a charge control agent may be contained. The toner base particles according to the present invention are obtained by a wet manufacturing method (for example, an emulsion aggregation method) produced in an aqueous medium.

<Binder resin (amorphous resin and crystalline resin)>
The toner base particles according to the present invention include an amorphous resin and a crystalline resin as a binder resin (binder resin). The toner base particles have a domain matrix structure in which a domain phase containing a crystalline resin is dispersed in a matrix phase containing an amorphous resin as described above. The matrix phase has a structure in which a domain phase having a closed interface (boundary between phases) exists in the matrix phase. The toner base particles according to the present invention show a state in which the crystalline resin is introduced incompatible with the amorphous resin. In addition, this structure can observe the cross section of the toner base particle dye | stained by the osmium by a usual method using a transmission electron microscope. In the case of cutting a section with an ultramicrotome, the thickness of the section is set to 100 nm. In addition to the crystalline resin, wax or the like may be added in the domain.

-Amorphous resin There is no particular limitation on the amorphous resin constituting the matrix phase, and conventionally known amorphous resins in this technical field can be used. Among these, amorphous resins are amorphous vinyl-based resins. It is preferable that resin is included. By including the vinyl resin in the amorphous resin, interaction with the vinyl cross-linked resin particles added as the external additive particles occurs, and the adhesiveness between the binder resin and the external additive particles is further increased. As a result of the improvement, the effects of the present invention can be expressed more remarkably. The “vinyl resin” is a resin obtained by polymerization using at least a vinyl monomer. Specific examples of the amorphous vinyl resin include an acrylic resin and a styrene acrylic copolymer resin. Among these, as the amorphous vinyl resin, a styrene acrylic copolymer resin formed using a styrene monomer and a (meth) acrylic acid ester monomer is preferable.

As the vinyl monomer that forms the amorphous vinyl resin, one or more selected from the following may 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 (meth) methyl acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate, T-butyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, phenyl (meth) acrylate, (meth ) Diethylaminoethyl acrylate, dimethylaminoethyl (meth) acrylate, and derivatives thereof.
(3) Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate and the like.
(4) Vinyl ethers 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-type monomer, it is preferable to use the monomer which has ionic dissociation groups, such as a carboxy group, a sulfonic acid group, and a phosphoric acid group, for example. Specifically, there are the following.
Examples of the monomer having a carboxy group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, and the like. Examples of the monomer having a sulfonic acid group include styrene sulfonic acid, allyl sulfosuccinic acid, 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 amorphous 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.

  As described above, the vinyl resin has been described in detail as a preferred form of the amorphous resin, but an amorphous polyester resin or the like may be used as the amorphous resin.

  The glass transition point (Tg) of the amorphous resin is preferably 25 to 60 ° C, more preferably 35 to 55 ° C. When the glass transition point of the amorphous resin is in the above range, sufficient low-temperature fixability and heat-resistant storage stability can be obtained at the same time. The glass transition point (Tg) of the amorphous resin is a value measured using “diamond DSC” (manufactured by PerkinElmer). As a measurement procedure, 3.0 mg of a measurement sample (amorphous 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 gel permeation chromatography (GPC) of an amorphous resin is 10,000-100,000 in a weight average molecular weight (Mw). In the present invention, the molecular weight of the amorphous resin GPC 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 of 0. The sample (non-crystalline resin) was flowed at 2 ml / min, dissolved in tetrahydrofuran to a concentration of 1 mg / ml under a dissolution condition in which the treatment was performed for 5 minutes using an ultrasonic disperser at room temperature, A sample solution is obtained by processing with a 2 μm membrane filter, and 10 μL of this sample solution is injected into the apparatus together with the carrier solvent, detected using a refractive index detector (RI detector), and the molecular weight distribution of the measurement sample. Using a calibration curve measured using monodisperse polystyrene standard particles Calculated. Ten polystyrenes are used for calibration curve measurement.

-Crystalline resin There is no particular limitation on the crystalline resin constituting the domain phase, and a conventionally known amorphous resin in this technical field can be used. In particular, the crystalline resin may contain a crystalline polyester resin. preferable. “Crystalline polyester resin” means a differential scanning among known polyester resins obtained by polycondensation reaction of divalent or higher carboxylic acid (polyvalent carboxylic acid) and divalent or higher alcohol (polyhydric alcohol). In calorimetry (DSC), it refers to a resin having a clear endothermic peak rather than a stepwise endothermic change. The clear endothermic peak specifically means a peak in which the half-value width of the endothermic peak is within 15 ° C. when measured at a rate of temperature increase of 10 ° C./min in differential scanning calorimetry (DSC). To do.

  The polyvalent carboxylic acid is a compound containing two or more carboxy groups in one molecule. Specifically, for example, oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, n-dodecyl succinic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, tetradacandiol Saturated aliphatic dicarboxylic acids such as cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid; trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid Acid; and 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. Specifically, for example, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol , 1,8-octanediol, 1,9-nonanediol, dodecanediol, neopentylglycol, 1,4-butenediol and other aliphatic diols; glycerin, pentaerythritol, trimethylolpropane, sorbitol A polyhydric alcohol etc. are mentioned. These may be used individually by 1 type and may be used in combination of 2 or more type.

  The melting point (Tm) of the crystalline polyester resin is preferably 50 to 95 ° C, more preferably 55 to 85 ° C. When the melting point of the crystalline polyester resin is in the above range, sufficient low-temperature fixability and excellent hot offset resistance can be obtained. The melting point of the crystalline polyester resin can be controlled by the resin composition.

  In the present invention, the melting point of the crystalline polyester resin is a value measured as follows. That is, using a differential scanning calorimeter “Diamond DSC” (manufactured by PerkinElmer Co., Ltd.), a first temperature raising process in which the temperature is raised from 0 ° C. to 200 ° C. at an elevation rate of 10 ° C./min, and a cooling rate of 10 ° C./min is 200 ° C. It is measured by the measurement conditions (temperature rise / cooling conditions) that pass through the cooling process for cooling from 0 to 0 ° C. and the second temperature raising process for raising the temperature from 0 ° C. to 200 ° C. at a raising / lowering rate of 10 ° C./min. The endothermic peak top temperature derived from the crystalline polyester resin in the first temperature raising process is defined as the melting point (Tm) based on the DSC curve obtained by this measurement. As a measurement procedure, 3.0 mg of a measurement sample (crystalline polyester resin) is sealed in an aluminum pan and set in a diamond DSC sample holder. The reference uses an empty aluminum pan.

  The molecular weight of the crystalline polyester resin measured by gel permeation chromatography (GPC) is 5,000 to 50,000 in terms of weight average molecular weight (Mw) and 1,500 to 25 in terms of number average molecular weight (Mn). , 000 is preferable. The molecular weight measured by GPC of the crystalline polyester resin is measured in the same manner as described above except that the crystalline polyester resin is used as a measurement sample.

  The mass ratio of the amorphous resin to the crystalline resin (amorphous resin / crystalline resin) is preferably 97/3 to 70/30, and more preferably 95/5 to 75/25. When the mass ratio (amorphous resin / crystalline resin) is in the above range, the crystalline resin constituting the domain phase is not exposed to the surface of the toner particles to be formed or is exposed even if it is exposed. An amount of crystalline resin that is extremely small and that can achieve low-temperature fixability can be introduced into the toner particles.

  The crystalline resin forming the domain preferably includes a crystalline resin formed by chemically bonding a vinyl polymer segment and a polyester polymer segment (hereinafter also simply referred to as “hybrid resin”). At this time, the vinyl polymer segment and the polyester polymer segment are preferably a crystalline resin bonded via both reactive monomers. In addition, the said polyester polymerization segment is comprised from crystalline polyester resin. When the crystalline resin contains the hybrid resin, an interaction with the vinyl-based crosslinked resin particles added as the external additive particles occurs, and the adhesion between the binder resin and the external additive particles is further improved. As a result, the operational effects of the present invention can be expressed more remarkably.

-Vinyl-type polymer segment The vinyl-type polymer segment which comprises a hybrid resin is comprised from resin obtained by superposing | polymerizing a vinyl-type monomer. Here, as the vinyl monomer, those described above as the monomers constituting the vinyl resin can be used in the same manner, and thus detailed description thereof is omitted here. In addition, it is preferable that content of the vinyl-type polymerization segment in a hybrid resin exists in the range of 5-30 mass%. Within this range, a good domain matrix structure can be obtained and the strength of the toner image can be increased.

-Polyester polymerization segment The polyester polymerization segment which comprises a hybrid resin is comprised from the crystalline polyester resin manufactured by performing polycondensation reaction in the presence of a catalyst with polyhydric carboxylic acid and polyhydric alcohol. 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 polyester polymer segment and a vinyl polymer segment. In the molecule, a hydroxy group or a carboxy group that forms a polyester polymer segment. , A monomer having both a group selected from an epoxy group, a primary amino group and a secondary amino group and an ethylenically unsaturated group forming a vinyl polymerized segment. Both reactive monomers are preferably monomers having a hydroxy group or a carboxy group and an ethylenically unsaturated group. More preferably, it is a monomer having a carboxy 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 these hydroxyalkyl (1 to 3 carbon atoms) esters. However, acrylic acid, methacrylic acid or fumaric acid is preferable from the viewpoint of reactivity. The polyester polymer segment and the vinyl polymer segment are bonded through 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 based on 100 parts by mass of the total amount of vinyl monomers constituting the vinyl polymer segment. 1-10 mass parts is preferable and 4-8 mass parts is more preferable.

-Manufacturing method of hybrid resin As a method of manufacturing hybrid resin, the existing general scheme can be used. The following three methods are listed as typical methods.
(1) A polyester polymerization segment is preliminarily polymerized, and the polyester polymerization segment is reacted with an amphoteric monomer, and further, an aromatic vinyl monomer and (meth) for forming a vinyl polymerization segment A method of forming a hybrid resin by reacting an acrylate monomer.
(2) A vinyl polymer segment is polymerized in advance, the vinyl polymer segment is reacted with an amphoteric monomer, and a polyvalent carboxylic acid and a polyhydric alcohol for forming a polyester polymer segment are further reacted. A method for forming a polyester polymer segment by causing the polyester polymer segment to form.
(3) A method in which a polyester polymer segment and a vinyl polymer segment are polymerized in advance, and then both reactive monomers are reacted with each other to bond them together.

  In the present invention, any of the above production methods can be used, but the method of the above item (2) is preferred. Specifically, a polyvalent carboxylic acid and a polyhydric alcohol that form a polyester polymer segment, a vinyl monomer that forms a vinyl polymer segment, and 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 polymer segment.

  Here, as a catalyst for synthesizing the polyester polymerization segment, various conventionally known catalysts can be used. In addition, examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin (II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamate. An acid etc. are mentioned.

<Colorant>
In the toner according to the present invention, when the toner base particles are configured to contain a colorant, the colorant may be contained in either the matrix phase or the domain phase. From the viewpoint, it is particularly preferable that it is contained in the matrix phase.

  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 of the colorant is preferably 1 to 10% by mass in the toner base particles, and more preferably 2 to 8% by mass.

<Release agent (offset prevention agent)>
In the toner according to the present invention, in the case where the toner base particles are configured to contain a release agent, the release agent may be contained in either the matrix phase or the domain phase. From the viewpoint of exudation of the surface of the mold, it is particularly preferable that it is contained in the matrix phase.

  As the wax, polyolefin waxes such as low molecular weight polypropylene, polyethylene, or oxidized polypropylene, polyethylene, and ester waxes such as behenate behenate can be preferably used.

Specifically, polyolefin waxes such as polyethylene wax and polypropylene wax; branched hydrocarbon waxes such as microcrystalline wax; long-chain hydrocarbon waxes such as paraffin wax and sazol wax; dialkyls such as distearyl ketone Ketone wax; carnauba wax, montan wax, behenate behenate, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanedioldi Ester wax such as stearate, trimellitic trimellitic acid, distearyl maleate; ethylenediamine behenylamide, trimellitic acid tristearylamide Such as amide waxes.
Among these, from the viewpoint of releasability during low-temperature fixing, it is preferable to use those having a low melting point, specifically, those having a melting point of 40 to 90 ° C. The content ratio of the release agent is preferably 1 to 20% by mass in the toner base particles, and more preferably 5 to 20% by mass.

<Charge control agent>
In the toner according to the present invention, when the toner base particles are configured to contain a charge control agent, the charge control agent may be contained in either the matrix phase or the domain phase. From the viewpoint of dispersibility, it is particularly preferred that it is contained in the matrix phase.

  The content ratio of the charge control agent is usually 0.1 to 10 parts by mass, preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the finally obtained binder resin.

(External additive particles)
The toner according to the present invention includes external additive particles in addition to the toner base particles. The external additive particles essentially contain vinyl-based crosslinked resin particles having a number average particle size of 30 to 300 nm.

  The vinyl-based crosslinked resin particles according to the present invention are not particularly limited, but specifically, particles composed of a crosslinked resin containing a structural unit derived from a crosslinkable vinyl monomer are preferable.

  As described above, the vinyl-based cross-linked resin particles according to the present invention are preferably particles composed of a resin containing a structural unit derived from a cross-linkable vinyl monomer capable of radical polymerization. Crosslinking by a radically polymerizable unsaturated group that is not involved in the polymerization among a plurality of radically polymerizable unsaturated groups or other reactive functional groups may be used without any particular limitation. The crosslinkable vinyl monomer is not particularly limited. Among them, as the crosslinkable vinyl monomer having a plurality of radically polymerizable unsaturated groups, for example, divinylbenzene, 1,4-divinyloxybutane, Vinyl compounds such as divinyl sulfone; diallyl phthalate and its isomers, triallyl isocyanurate and derivatives thereof, allyl compounds such as triallyl trimethate; ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, etc. (Poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate and other (poly) oxyalkylene glycol di (meth) acrylate; pentaerythritol tetra (me ) Acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) ) Acrylate, glycerol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, tetramethylol methane tri (meth) acrylate, tetramethylolpropane tetra (meth) acrylate, etc. (Meth) acrylic compounds; and the like. “(Meth) acrylate” means “acrylate” or “methacrylate”.

  Similarly, among the crosslinkable vinyl monomers, examples of the crosslinkable vinyl monomer having a reactive functional group other than a radically polymerizable unsaturated group include an epoxy group as a reactive functional group. , A radical polymerizable vinyl monomer having an amino group, a carboxyl group, a hydroxyl group, a thiohydroxyl group (—SH group), and the like. Specifically, hydroxyethyl (meth) acrylate, dimethylaminoethyl ( Preferable examples include (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylic acid, (meth) acrylamide and the like. These crosslinkable vinyl monomers may be used alone or in combination of two or more.

  In the vinyl-based crosslinked resin particles according to the present invention, the content of the structural unit derived from the crosslinkable vinyl monomer is not particularly limited, but is preferably 0.5 to 100% by mass, more preferably 3 It is -90 mass%, More preferably, it is 5-50 mass%. If it is 0.5 mass% or more, the strength is increased, and a spacer effect over a long period of time can be obtained.

  In the vinyl-based cross-linked resin particles according to the present invention, in addition to the structural unit derived from the cross-linkable vinyl monomer, a structural unit derived from a non-cross-linkable vinyl monomer capable of radical polymerization, and other radical polymerizable units. A structural unit derived from a monomer may be contained.

  Although it does not specifically limit as said non-crosslinkable vinyl monomer, For example, styrene, p- (m-) methylstyrene, p- (m-) ethylstyrene, p- (m-) chlorostyrene, p- ( m-) styrene-based monomers such as chloromethylstyrene, styrenesulfonic acid, p- (m-) t-butoxystyrene, α-methyl-pt-amyloxystyrene, pt-amyloxystyrene; Methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylamino Ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, diethylene glycol mono (meth) acrylate (Meth) acrylic acid ester monomers such as glycerol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, butanediol mono (meth) acrylate; unsaturated carboxylic acids such as (meth) acrylic acid and maleic acid Monomers; alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; vinyl ester monomers such as vinyl acetate and vinyl butyrate; (meth) acrylonitrile, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide; and the like. These may be used alone or in combination of two or more.

  Although it does not specifically limit as said other radically polymerizable monomer, For example, Polyethylene glycol components, such as monomers having hydroxy groups, such as hydroxyethyl (meth) acrylate; And the like. These may be used alone or in combination of two or more. Also, trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, pentanefluoropropyl (meth) acrylate, octafluoroamyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, perfluorobutylethyl (meth) Fluorine atom-containing (meth) acrylates such as acrylate; These may be used alone or in combination of two or more.

  In the vinyl-based crosslinked resin particles according to the present invention, the structural unit derived from the non-crosslinkable vinyl monomer and the structural unit derived from another radical polymerizable monomer are structural units derived from the crosslinkable vinyl monomer. It may be included outside the range of the content ratio.

  The number average particle diameter of the vinyl-based crosslinked resin particles according to the present invention is essential to be 30 to 300 nm, and preferably 50 to 200 nm. If the average particle size is less than 30 nm, the effect of suppressing coalescence of the crystalline resin is low, and the spacer effect is also low. As a result, sufficient image strength cannot be achieved, and fogging is also suppressed. I can't. Further, when the average particle diameter exceeds 300 nm, there is a problem in that the occurrence of fogging cannot be suppressed as a result of the increase of desorption from the toner. In this specification, the number average particle diameter of the vinyl-based cross-linked resin particles is determined by using a scanning electron microscope (SEM) “JEM-7401F” (manufactured by JEOL Ltd.) and a toner (development) of 30,000 times. In the case of the toner in the agent flow, the organic fine particles may be crushed. Therefore, the SEM photograph of the toner in the bottle is taken in with a scanner, and the SEM photograph is taken with an image processing analysis apparatus “LUZEX AP” (manufactured by Nireco). The vinyl cross-linked resin particles in the image are binarized, the horizontal ferret diameter for 100 vinyl cross-linked resin particles is calculated, and the average value is taken as the number average particle diameter. At this time, it is necessary to distinguish from inorganic particles by EDS.

  For vinyl-based crosslinked resin particles, the amount of precipitate produced when vacuum-dried is measured by the following measurement method, preferably 20% by mass or less, and more preferably 5% by mass or less, based on the total amount. preferable.

(Measurement method of amount of sediment)
About 0.3 g of the dried vinyl-based crosslinked resin particles are weighed as a sample, put into 30 g of tetrahydrofuran, and stirred for 60 minutes. Next, the centrifuge “H-900” (manufactured by Kokusan Co., Ltd.) is centrifuged at 20000 rpm for 5 minutes. Then, after drying a deposit with a vacuum dryer, the mass is measured.

  The method for producing vinyl-based crosslinked resin particles according to the present invention includes a step of radical polymerization of a radical polymerizable monomer containing a crosslinkable vinyl monomer.

  The vinyl-based crosslinked resin particles are particles obtained by radical polymerization of a radically polymerizable monomer containing a crosslinkable vinyl monomer, and the crosslinkable vinyl monomer is as described above. Moreover, although the crosslinked resin particle can be obtained by using a crosslinkable vinyl monomer, the crosslinked form is not particularly limited, and a desired crosslinked form depends on the kind of the crosslinkable vinyl monomer to be used. It can be. For example, among other radical polymerizable unsaturated groups, there may be crosslinking by radical polymerizable unsaturated groups that did not participate in polymerization, for example, crosslinking by dehydration condensation of hydroxy groups and crosslinking by reaction of epoxy groups and amino groups, etc. And cross-linking with a functional group having the following reactivity.

  Although there is no restriction | limiting in particular about the manufacturing method of the said vinyl type crosslinked resin particle, For example, an emulsion polymerization method (a soap free is also included) is mentioned. Specifically, the emulsion polymerization method is a mixture of a medium such as water, a monomer that is hardly soluble in the medium, and an emulsifier (surfactant), and a polymerization initiator (usually a radical generator) that can be dissolved in the medium. ).

  The addition amount of the above-described vinyl-based crosslinked resin particles is not particularly limited, but is preferably 0.05 to 3.0% by mass, more preferably 0.25 to 1.5% with respect to 100% by mass of the toner base particles. % By mass. If it is 0.05% by mass or more, the effect of addition can be sufficiently exhibited, while if it is 3.0% by mass or less, carrier contamination by excessively added vinyl-based crosslinked resin particles is suppressed. Therefore, it is preferable because a decrease in the charge amount after durability can be prevented.

  In addition to the vinyl-based crosslinked resin particles described above, other conventionally known external additive particles may be added. Examples of such external additive 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, or titanic acid. Examples thereof include fine particles of inorganic titanate compounds such as strontium and zinc titanate. These can be used individually by 1 type or in combination of 2 or more types. These inorganic fine particles are preferably subjected to a gloss treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, a silicone oil or the like in order to improve heat-resistant storage stability and environmental stability. However, the content of the vinyl-based crosslinked resin particles in the total amount of the external additive particles is preferably 5 to 100% by mass, and more preferably 10 from the viewpoint of sufficiently expressing the effects of the present invention. -80 mass%.

(Toner glass transition point)
The glass transition point (Tg) of the toner according to 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, sufficient low-temperature fixing property and heat-resistant storage property can be obtained at the same time. 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 size can be controlled by the concentration of the flocculant used during production, the amount of organic solvent added, the fusing time, the composition of the binder resin, and the like. When the volume-based median diameter is in the above range, a very small dot image of 1200 dpi level can be faithfully reproduced. The volume-based median diameter of the toner is measured and calculated using a measuring device in which a computer system equipped with data processing software “Software V3.51” is connected to “Multisizer 3” (manufactured by Beckman Coulter). It 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). Solution) and ultrasonically dispersed for 1 minute to prepare a toner dispersion, and this toner dispersion is a beaker containing “ISOTON II” (manufactured by Beckman Coulter) in a sample stand. Then, inject with a pipette until the displayed concentration of the measuring device is 8%. Here, a reproducible measurement value can be obtained by setting the concentration range. In the measuring apparatus, the measurement particle count number is 25000, the aperture diameter is 100 μm, and the frequency value is calculated by dividing the range of 2 to 60 μm, which is the measurement range, into 256 parts. % Particle diameter is defined as the 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 0.930 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). Specifically, the measurement sample (toner) was blended with an aqueous solution containing a surfactant, dispersed by performing ultrasonic dispersion for 1 minute, and then subjected to measurement conditions HPF by “FPIA-2100” (manufactured by Sysmex). In the (high magnification imaging) mode, images are taken 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, and the circularity of each toner particle is added. And a value calculated by 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>
<Method for producing toner base particles>
The toner base particles according to the present invention can be produced by an emulsion aggregation method. That is, for example, an aqueous dispersion of amorphous resin fine particles composed of a vinyl resin, an aqueous dispersion of crystalline resin fine particles composed of, for example, a hybrid resin, and an aqueous dispersion of colorant fine particles are mixed, Toner base particles having a domain matrix structure can be obtained by aggregating and then fusing the respective fine particles.

  Further, the toner base particles having a core-shell structure can be obtained by using the toner base particles as a core and providing a shell layer on the surface thereof. By adopting a core-shell structure, heat-resistant storage properties and low-temperature fixability can be further improved. In the case of the core-shell type, it is preferable that a domain matrix structure exists in the core.

When the toner base particles according to the present invention are manufactured by the emulsion aggregation method, a production example of toner base particles containing a colorant is specifically shown.
(1) A step of preparing a dispersion of amorphous resin fine particles in an aqueous medium, that is, in the aqueous medium, amorphous resin fine particles composed of, for example, a vinyl resin are formed by polymerization, and the amorphous Step of preparing an aqueous dispersion of amorphous resin fine particles in which crystalline resin fine particles are dispersed (2) Step of preparing a dispersion of crystalline resin fine particles composed of, for example, a hybrid resin in an aqueous medium (3) Water based Step (4) of preparing a dispersion of colorant fine particles in a medium, mixing the dispersion of amorphous resin fine particles, the dispersion of crystalline resin fine particles, and the dispersion of colorant fine particles, Step of aggregating the amorphous resin fine particles, the crystalline resin fine particles, and the colorant fine particles and then fusing (5) Washing and drying the particles obtained by the agglomeration and fusing, toner base particles Can form Kill.

<Method for producing toner particles>
(External additive addition process)
The external additive adding step is a step of preparing toner particles by adding and mixing the external additive particles to the dried toner base particles. 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 developing electrostatic latent image>
The toner according to 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. 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 magnetic fine powder is dispersed in a binder resin, or the like may be used.

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

  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”.

<Electrophotographic image forming method>
The developer for developing an electrostatic latent image 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”). 4 cycle type image forming method, and a color developing device for each color and an image forming unit having an electrostatic latent image carrier for each color, An image forming method can also be used.

  As an electrophotographic image forming method, specifically, using the developer for developing an electrostatic latent image according to the present invention, for example, charging on an 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 sheet (transfer process), and then the toner image transferred onto the sheet is fixed on the sheet (fixing process) by a contact heating type fixing process to obtain a visible image.

  The effects of the present invention will be described using the following examples and comparative examples. In the following examples, “parts” and “%” mean “parts by mass” and “mass%”, respectively, unless otherwise specified, and each operation is performed at room temperature (25 ° C.). In addition, this invention is not limited to an Example below.

(Preparation of vinyl resin particles 1)
A glass reactor equipped with a thermometer, reflux condenser, nitrogen gas inlet tube, and stirrer was charged with 200 parts of deionized water and 3 parts of sodium lauryl sulfate, and heated to 80-85 ° C. while ventilating nitrogen gas. Then, 1 part of ammonium persulfate is added under stirring, and a monomer mixture comprising 40 parts of methyl methacrylate as a non-crosslinkable monomer and 40 parts of styrene and 20 parts of divinylbenzene as a crosslinkable monomer is added. It was added dropwise over time and then stirring was continued for 1 hour. The emulsion thus obtained was dried by spray drying to obtain particles having a number average particle diameter of 100 nm.

(Preparation of vinyl resin particles 2-13)
The types and mass ratios of the non-crosslinkable monomer and the crosslinkable monomer are changed as shown in Table 1 below, and the number average particle size of the obtained particles becomes the value shown in Table 1 below. Vinyl resin particles 2 to 13 were prepared in the same manner as the vinyl resin particle 1 described above except that the amount of sodium lauryl sulfate was adjusted.

(Preparation of amorphous resin fine particle dispersion 1)
First stage polymerization A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device was charged with a solution obtained by dissolving 4 parts of polyoxyethylene (2) sodium dodecyl ether sulfate in 3000 parts of ion-exchanged water, The internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. After raising the temperature, 10 parts of potassium persulfate dissolved in 200 parts of ion-exchanged water was added to obtain a liquid temperature of 75 ° C.
-After dropping a monomer mixture consisting of 584 parts by mass of styrene, 160 parts by mass of n-butyl acrylate, and 56 parts by mass of methacrylic acid over 1 hour, polymerization is performed while heating and stirring at 75 ° C for 2 hours. Thus, a dispersion of resin fine particles [b1] was prepared.

Second stage polymerization A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device was charged with a solution obtained by dissolving 2 parts of polyoxyethylene (2) sodium dodecyl ether sulfate in 3000 parts of ion-exchanged water, The internal temperature was raised to 80 ° C. Next, 42 parts (in terms of solid content) of the dispersion of resin fine particles [b1] obtained above and 70 parts of microcrystalline wax “HNP-0190” (manufactured by Nippon Seiwa Co., Ltd.)
・ Styrene 239 parts by mass ・ n-butyl acrylate 111 parts by mass ・ methacrylic acid 26 parts by mass ・ n-octyl mercaptan 3 parts by mass A dispersion containing emulsified particles (oil droplets) was prepared by mixing and dispersing for 1 hour using a mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.).

  Next, an initiator solution in which 5 parts of potassium persulfate is dissolved in 100 parts of ion-exchanged water is added to this dispersion, and this system is heated and stirred at 80 ° C. for 1 hour to perform polymerization. A dispersion of fine particles [b2] was prepared.

Third stage polymerization A solution prepared by dissolving 10 parts of potassium persulfate in 200 parts of ion-exchanged water was added to the dispersion of resin fine particles [b2] obtained above.
-A monomer mixture consisting of 380 parts by mass of styrene, 132 parts by mass of n-butyl acrylate, 39 parts by mass of methacrylic acid, and 6 parts by mass of n-octyl mercaptan was added dropwise over 1 hour. After completion of the dropwise addition, polymerization was carried out by heating and stirring for 2 hours, and then cooled to 28 ° C. to prepare amorphous resin fine particle dispersion 1.

(Preparation of amorphous resin fine particle dispersion 2)
In the preparation of the amorphous resin fine particle dispersion 1, the monomer composition of the first stage polymerization is changed to: styrene 545 parts by mass, n-butyl acrylate 199 parts by mass, methacrylic acid 56 parts by mass, the second stage polymerization The monomer composition of the polymerization was changed to 217 parts by mass of styrene, 133 parts by mass of n-butyl acrylate, 26 parts by mass of methacrylic acid, and 3 parts by mass of n-octyl mercaptan. Amorphous resin fine particle dispersion 2 was prepared in the same manner except that styrene was changed to 349 parts by mass, n-butyl acrylate 165 parts by mass, methacrylic acid 39 parts by mass, and n-octyl mercaptan 6 parts by mass.

(Preparation of amorphous resin fine particle dispersion 3)
A polymerization initiator solution in which 8.5 parts of potassium persulfate is dissolved in 200 parts of ion-exchanged water is added to 1390 parts of ion-exchanged water, and 292 parts of styrene and 86 parts of n-butyl acrylate are obtained at a temperature of 80 ° C. A monomer mixture consisting of 42 parts of methacrylic acid and 8.2 parts of n-octyl mercaptan was added dropwise over 2 hours. After completion of the dropwise addition, polymerization was performed by heating and stirring for 2 hours, and then cooled to 28 ° C. to prepare amorphous resin fine particle dispersion 3.

(Synthesis of amorphous resin 4 made of polyester resin)
In a 10-liter four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer and a thermocouple, 500 parts of bisphenol A propylene oxide 2-mol adduct, 117 parts of terephthalic acid, 82 parts of fumaric acid and an esterification catalyst ( 2 parts of tin octylate) was added, subjected to a condensation polymerization reaction at 230 ° C. for 8 hours, further reacted at 2 kPa for 2 hours, and cooled to 160 ° C. to obtain an amorphous resin 4 made of a polyester resin.

(Preparation of amorphous resin fine particle dispersion 4)
4100 parts of the amorphous resin obtained above was dissolved in 400 parts of ethyl acetate. Next, 25 parts of a 5.0% aqueous sodium hydroxide solution was added to prepare an amorphous resin solution. While stirring this amorphous resin solution into a container having a stirring device, 638 parts of a 0.26% aqueous sodium lauryl sulfate solution was added dropwise and mixed over 30 minutes. During the dropwise addition of the sodium lauryl sulfate aqueous solution, the liquid in the reaction vessel became cloudy, and after adding the entire amount of the sodium lauryl sulfate aqueous solution, an emulsion was prepared in which amorphous resin fine particles were uniformly dispersed. Next, the emulsion is heated to 40 ° C., and ethyl acetate is distilled off under reduced pressure of 150 hPa using a diaphragm vacuum pump “V-700” (manufactured by BUCHI), thereby forming a non-polyester resin. An amorphous resin fine particle dispersion 4 in which the crystalline resin fine particles are dispersed was obtained.

(Synthesis of crystalline resin 1 made of polyester resin)
220 parts of sebacic acid (molecular weight 202.25) as the polyvalent carboxylic acid compound and 298 parts of 1,12-dodecanediol (molecular weight 202.33) as the polyhydric alcohol compound were added to the nitrogen introduction tube, dehydration tube, and stirrer. And placed in a reaction vessel equipped with a thermocouple, heated to 160 ° C. and dissolved. 2.5 parts of tin (II) 2-ethylhexanoate and 0.2 part of gallic acid were added, the temperature was raised to 210 ° C., and the reaction was performed for 8 hours. Furthermore, reaction was performed at 8.3 kPa for 1 hour to obtain a crystalline resin 1 made of a polyester resin.

  About the obtained crystalline resin 1, using the differential scanning calorimeter “Diamond DSC” (manufactured by PerkinElmer Co., Ltd.) as described above, a DSC curve was obtained under the condition of a heating rate of 10 ° C./min. It was 82.8 degreeC when melting | fusing point (Tm) was measured by the method of measuring a peak top temperature. Further, when the molecular weight was measured by GPC “HLC-8120GPC” (manufactured by Tosoh Corporation) as described above, the Mw in terms of standard styrene was 28000.

(Preparation of crystalline resin fine particle dispersion 1)
The crystalline resin fine particle dispersion 1 was prepared in the same manner as the amorphous resin fine particle dispersion 4 except that the crystalline resin 1 obtained above was used instead of the amorphous resin 4. did.

(Synthesis of crystalline resin 2 made of hybrid resin)
A nitrogen-introducing tube contains 220 parts of sebacic acid (molecular weight 202.25) as a polyvalent carboxylic acid compound and 298 parts of 1,12-dodecanediol (molecular weight 202.33) as a polyhydric alcohol compound. In a reaction vessel equipped with a dehydration tube, a stirrer and a thermocouple, the mixture was heated to 160 ° C. and dissolved. On the other hand, a solution of 46 parts of styrene, 12 parts of n-butyl acrylate, 4 parts of dicumyl peroxide, and 3 parts of acrylic acid as a bireactive monomer, which is a premixed vinyl polymer segment material, is added by a dropping funnel. The solution was added dropwise over 1 hour. Stirring was continued for 1 hour while maintaining at 170 ° C., and after polymerization of styrene, n-butyl acrylate and acrylic acid, 2.5 parts of tin (II) 2-ethylhexanoate and 0.2 part of gallic acid were added. The temperature was raised to 210 ° C. and the reaction was carried out for 8 hours. Furthermore, reaction was performed at 8.3 kPa for 1 hour, and the crystalline resin 2 which consists of hybrid resins was obtained.

(Preparation of crystalline resin fine particle dispersion 2)
The crystalline resin fine particle dispersion 2 was prepared in the same manner as the amorphous resin fine particle dispersion 4 except that the crystalline resin 2 obtained above was used instead of the amorphous resin 4. did.

(Preparation of colorant fine particle dispersion [Bk])
90 parts of polyoxyethylene-2-dodecyl ether sodium sulfate was stirred and dissolved in 1510 parts of ion-exchanged water. While stirring this solution, 400 parts of carbon black “Regal 330” (Cabot Corp.) is gradually added, and then dispersed by using a stirring device “Claremix” (M Technique Corp.). A colorant fine particle dispersion [Bk] was prepared.

Example 1 Preparation of Toner 1
<Aggregation / fusion process>
In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device, 1300 parts of amorphous resin fine particle dispersion (converted to solid content), 60 parts of crystalline resin fine particle dispersion 1 (converted to solid content), ion 1100 parts of exchange water and 40 parts of a colorant fine particle dispersion [Bk] (solid content conversion) were charged and the liquid temperature was adjusted to 30 ° C., and then a 5N sodium hydroxide aqueous solution was added to adjust the pH to 10. Next, an aqueous solution obtained by dissolving 60 parts of magnesium chloride in 60 parts of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. The temperature was raised after holding for 3 minutes, and the temperature of the system was raised to 85 ° C. over 60 minutes, agglomerating while maintaining 85 ° C., and the particle growth reaction was continued. In this state, the particle size of the aggregated particles was measured with “Coulter Multisizer 3” (manufactured by Beckman Coulter), and when the volume-based median diameter reached 6 μm, 40 parts of sodium chloride was added to ion-exchanged water 160 The aqueous solution dissolved in the part is added to stop the particle growth, and further, as a ripening step, the mixture is heated and stirred at a liquid temperature of 80 ° C. for 1 hour to promote fusion between the particles. A dispersion was prepared.

<Washing and drying process>
The dispersion of toner base particles 1 prepared as described above was subjected to solid-liquid separation with a basket-type centrifuge “MARK III model number 60 × 40 + M” (manufactured by Matsumoto Kikai Co., Ltd.) to form a wet cake of toner base particles. The wet cake was washed with ion exchange water at 40 ° C. using the basket type centrifuge until the electric conductivity of the filtrate reached 5 μS / cm, and then the “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.). The toner base particles 1 were prepared by transferring and drying until the water content became 0.5%.

<External additive addition process>
To 1100 parts of toner base particles, 1 part of hydrophobic silica (volume-based median diameter = 12 nm), 0.3 part of hydrophobic titania (volume-based median diameter = 20 nm) and 11 parts of vinyl resin particles are added, and Henschel is added. Toner 1 was prepared by mixing with a mixer.

(Example 2: Preparation of toner 2)
A toner 2 was prepared in the same manner as the toner 1 described above except that the crystalline resin fine particle dispersion 2 was used instead of the crystalline resin fine particle dispersion 1.

(Example 3: Preparation of toner 3)
Toner 3 was prepared in the same manner as toner 1 described above except that vinyl resin particles 2 were used instead of vinyl resin particles 1.

(Example 4: Preparation of toner 4)
A toner 4 was prepared in the same manner as the toner 1 described above except that the vinyl resin particles 3 were used instead of the vinyl resin particles 1.

(Example 5: Preparation of toner 5)
A toner 5 was produced in the same manner as in the production of the toner 1 except that the vinyl resin particles 4 were used in place of the vinyl resin particles 1.

(Example 6: Preparation of toner 6)
A toner 6 was prepared in the same manner as the toner 1 described above except that the vinyl resin particles 5 were used in place of the vinyl resin particles 1.

Example 7 Production of Toner 7
A toner 7 was prepared in the same manner as the toner 1 described above except that the vinyl resin particles 6 were used instead of the vinyl resin particles 1.

Example 8 Production of Toner 8
A toner 8 was produced in the same manner as in the production of the toner 1 except that the amount of the vinyl resin particles 1 added in the external additive addition step was 0.04 part.

Example 9 Production of Toner 9
A toner 9 was prepared in the same manner as the preparation of the toner 1 except that the amount of the vinyl resin particles 1 added in the external additive addition step was 0.05 parts.

Example 10 Production of Toner 10
A toner 10 was prepared in the same manner as the preparation of the toner 1 except that the amount of the vinyl resin particles 1 added in the external additive addition step was 3 parts.

Example 11 Production of Toner 11
A toner 11 was prepared in the same manner as in the preparation of the toner 1 except that the amount of the vinyl resin particles 1 added in the external additive addition step was 3.1 parts (Example 12: Preparation of the toner 12)
<Aggregation / fusion process>
In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device, 2270 parts of amorphous resin fine particle dispersion (converted to solid content), 160 parts of crystalline resin fine particle dispersion (converted to solid content), ion 1100 parts of exchange water and 40 parts of a colorant fine particle dispersion [Bk] (solid content conversion) were charged and the liquid temperature was adjusted to 30 ° C., and then a 5N sodium hydroxide aqueous solution was added to adjust the pH to 10. Next, an aqueous solution obtained by dissolving 60 parts of magnesium chloride in 60 parts of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. The temperature was raised after holding for 3 minutes, and the temperature of the system was raised to 85 ° C. over 60 minutes, agglomerating while maintaining 85 ° C., and the particle growth reaction was continued. In this state, the particle size of the aggregated particles is measured with “Coulter Multisizer 3” (manufactured by Beckman Coulter), and when the volume-based median diameter becomes 5.5 μm, an amorphous resin is used as a shell material. 330 parts of a fine particle dispersion (in terms of solid content) was added. Further, an aqueous solution in which 2 parts of magnesium chloride hexahydrate was dissolved in 2 parts of ion-exchanged water was added over 10 minutes, and stirring was continued until the volume-based median diameter of the particles reached 6 μm. At this point, an aqueous solution in which 40 parts of sodium chloride is dissolved in 160 parts of ion-exchanged water is added to stop particle growth, and the mixture is heated and stirred at a liquid temperature of 80 ° C. for 1 hour as an aging process. The fusion was advanced, whereby a dispersion of toner base particles 12 was obtained.

<Washing and drying process>
The dispersion of toner base particles 1 prepared as described above was solid-liquid separated and then washed and dried in the same manner as in the preparation of toner 1 to prepare toner base particles 12 having a core-shell structure.

<External additive addition process>
Toner 12 was prepared in the same manner as toner 1 except that toner base particles 12 were used.

Example 13 Production of Toner 13
A toner 13 was prepared in the same manner as the preparation of the toner 1 except that the amorphous resin fine particle dispersion 4 was used instead of the amorphous resin fine particle dispersion 1.

Example 14 Production of Toner 14
A toner 14 was prepared in the same manner as the preparation of the toner 1 except that the vinyl resin particles 7 were used instead of the vinyl resin particles 1.

Example 15 Production of Toner 15
A toner 15 was produced in the same manner as in the production of the toner 1 except that the vinyl resin particles 8 were used instead of the vinyl resin particles 1.

Example 16 Production of Toner 16
A toner 16 was produced in the same manner as in the production of the toner 1 except that the vinyl resin particles 9 were used instead of the vinyl resin particles 1.

(Example 17: Preparation of toner 17)
A toner 17 was produced in the same manner as in the production of the toner 1 except that the vinyl resin particles 10 were used instead of the vinyl resin particles 1.

(Comparative Example 1: Preparation of Toner 18)
A toner 18 was produced in the same manner as in the production of the toner 1 except that the amorphous resin fine particle dispersion 1 was not used in the aggregation / fusion process.

(Comparative Example 2: Preparation of Toner 19)
A toner 19 was prepared in the same manner as the preparation of the toner 1 except that sol-gel silica (HMDS treatment, hydrophobicity 72%, number average particle size 100 nm) was used instead of the vinyl resin particles 1.

(Comparative Example 3: Preparation of Toner 20)
A toner 20 was prepared in the same manner as the preparation of the toner 1 except that the vinyl resin particles 11 were used instead of the vinyl resin particles 1.

(Comparative Example 4: Preparation of Toner 21)
A toner 21 was prepared in the same manner as in the preparation of the toner 1 except that the vinyl resin particles 12 were used instead of the vinyl resin particles 1.

(Comparative Example 5: Preparation of toner 22)
A toner 22 was produced in the same manner as in the production of the toner 1 except that the vinyl resin particles 13 were used instead of the vinyl resin particles 1.

(Comparative Example 6: Preparation of toner 23)
A toner 23 was prepared in the same manner as the toner 18 described above except that the amorphous resin fine particle dispersion 4 was used instead of the amorphous resin fine particle dispersion 1.

(Comparative Example 7: Preparation of toner 24)
A toner 24 was produced in the same manner as in the production of the toner 1 except that the vinyl resin particles 1 were not added in the external additive addition step.

[Evaluation of toner]
(Evaluation of image intensity)
Developers 1 to 24 were prepared by mixing each of the toners 1 to 24 obtained above with a ferrite carrier having a volume-based median diameter of 60 μm so that the toner concentration was 6% by mass. A V-type mixer was used for mixing the carrier and the toner, and the mixing time was 30 minutes.

In a monochrome copying machine “bizhub PRO C1250” (manufactured by Konica Minolta Co., Ltd.), a fixing device is modified so that the surface temperature (fixing temperature) of the heating roller can be changed within a range of 100 to 200 ° C. In a normal humidity environment (temperature 20 ° C., humidity 50% RH), a fixing experiment in which a solid image with a toner adhesion amount of 5 mg / cm ² is fixed on high-quality paper of A4 size was set at a fixed fixing temperature of 150 ° C. went. As a result, an offset was confirmed only for the toner 18.

  Further, with respect to the evaluation sample, the fixing rate of the toner image at the crease on the paper was evaluated as an index of the crease fixability (strength). Specifically, when the toner fixed image was bent toward the inner surface, the degree of toner peeling at the bent portion was evaluated as the fixing rate. The measurement method is to fold a solid image part (image density is 0.8) with the image side inward, rub the fold three times with a finger, open the image, and use “JK Wiper” (manufactured by Nippon Paper Crecia). It is a value calculated by the following equation from the image density before and after folding the crease portion of the solid image after wiping three times.

Fixing rate (%) = {(image density after folding) / (image density before folding)} × 100
The higher the fixing rate, the better the crease fixing property (that is, the higher the strength of the toner image). In this case, 60% or more was considered acceptable. The ranking criteria are as follows, and the results are shown in Table 2 below.

Crease fixing rate of 90% or higher: Rank 5
Crease fixing rate of 75% or more and less than 90%: Rank 4
Crease fixing rate 60% or more and less than 75%: Rank 3
Crease fixing rate of 30% or more and less than 60%: Rank 2
Crease fixing rate of less than 30%: Rank 1
(Fog evaluation)
Using a monochrome copying machine “bizhub PRO C1250” (manufactured by Konica Minolta Co., Ltd.), in a normal temperature and humidity environment (temperature 23 ° C., humidity 55% RH), a character image with a printing rate of 5% is printed on A4 quality paper (80 g / m ² And formed 300,000 sheets. In the initial stage of printing and after printing 300,000 sheets, white solid images were formed on A4 fine paper (80 g / m ² ), and fog was evaluated on the obtained printed matter.

The fog was evaluated as follows. First, with respect to non-printed A4 fine paper (80 g / m ² ), the absolute image density at 20 locations was measured with a Macbeth reflection densitometer “RD-918” (manufactured by Gretag Macbeth), and an average value was calculated. Blank paper density was used. Next, for each solid white image at the initial stage of printing and after printing 300,000 sheets, similarly, the absolute image density at 20 locations was measured to calculate an average value, and the value obtained by subtracting the blank paper density from this average value was converted to fog. The density difference was evaluated. The fog density difference was less than 0.10, and the test was accepted. The results are shown in Table 2 below.

  From the results shown in Table 2, it can be seen that with the developer using the toner according to the present invention, a decrease in image density and occurrence of fog are suppressed, and stable image formation is possible.

Claims (6)

Toner base particles having a domain matrix structure in which a domain phase containing a crystalline resin is dispersed in a matrix phase containing an amorphous resin;
External additive particles;
An electrostatic latent image developing toner comprising:
The toner for developing an electrostatic latent image, wherein the external additive particles include vinyl-based crosslinked resin particles having a number average particle diameter of 30 to 300 nm.   The electrostatic latent image developing toner according to claim 1, wherein the amorphous resin includes a vinyl resin.   The electrostatic latent image developing toner according to claim 1, wherein the crystalline resin contains a crystalline polyester resin.   The electrostatic latent image developing toner according to claim 1, wherein the crystalline resin includes a crystalline resin formed by chemically bonding a vinyl polymer segment and a polyester polymer segment.   The electrostatic latent image developing toner according to claim 1, wherein the number average particle diameter is 50 to 200 nm.   The electrostatic latent image according to any one of claims 1 to 5, wherein a content of the vinyl-based crosslinked resin particles is 0.05 to 3.0% by mass with respect to 100% by mass of the toner base particles. Development toner.