Pigment-containing polyester resin particles, electrostatic latent image developing toner, method for producing same, image

Abstract

A pigment-containing polyester resin particle, an electrostatic latent image developing toner, a method for producing the pigment-containing polyester resin particle, an image forming apparatus, and a method for producing the electrostatic latent image developing toner, the pigment-containing polyester resin particle containing a polyester resin and a pigment, the pigment is not exposed to the surfaces of the pigment-containing polyester resin particles and is not inscribed with the contours of the pigment-containing polyester resin particles.

Description

Technical Field

[0001] The present invention relates to a pigment-containing polyester resin particle, a method for producing the pigment-containing polyester resin particle, a toner for developing an electrostatic latent image, an electrostatic latent image developer, a toner cartridge, a processing cartridge, an image forming apparatus, and an image forming method. Background Art

[0002] Patent document 1 discloses a color toner for electrostatic latent image development, which includes colored resin particles and an external additive. The colored resin particles contain at least a binder resin, a colorant, a charge control agent and a release agent. In the color toner for electrostatic latent image development, the colorant is a resin-coated pigment whose surface is coated with a resin and has an average primary particle size of 30 to 300 nm. In the resin-coated pigment, the tetrahydrofuran-insoluble component of the coated resin is 80 to 100% by mass.

[0003] Patent document 2 discloses a method for producing an aqueous dispersion of a polymer-encapsulated pigment, which comprises the following steps: (a) preparing an aqueous pigment dispersion comprising an organic pigment P, a surfactant T and water; (b) preparing a monomer microemulsion in water comprising a polymerizable monomer M and a surfactant T, wherein the monomer microemulsion in water is stabilized at 20° C. by a hydrophobic organic compound having a water solubility of 5×10-5 g / l or less; (c) generating a monomer microemulsion containing a pigment by mixing and homogenizing the aqueous pigment dispersion from (a) and the monomer microemulsion from (b); and (d) polymerizing the pigment-containing monomer microemulsion from (c) in the presence of a polymerization initiator and / or by heat, while encapsulating the pigment with the formed polymer.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2013-073086

[0005] Patent Document 2: Japanese Patent Application No. 2007-534810 Summary of the invention

[0006] An object of the present invention is to provide pigment-containing polyester resin particles having a small amount of coarse particles.

[0007] Specific means for solving the above-mentioned problems include the following aspects.

[0008] <1>

[0009] A pigment-containing polyester resin particle, comprising a polyester resin and a pigment, wherein the pigment-containing polyester resin particle comprises:

[0010] The pigment is not exposed on the surface of the pigment-containing polyester resin particle and is not inscribed in the outline of the pigment-containing polyester resin particle.

[0011] <2>

[0012] The pigment-containing polyester resin particles according to <1>, wherein

[0013] The volume average particle size is 50 nm or more and 500 nm or less.

[0014] <3>

[0015] The pigment-containing polyester resin particles according to <1> or <2>, wherein

[0016] The content of the pigment is 10% by mass or more and 60% by mass or less.

[0017] <4>

[0018] The pigment-containing polyester resin particles according to any one of <1> to <3>, wherein

[0019] The average diameter of the pigment is 10 nm or more and 400 nm or less.

[0020] <5>

[0021] The pigment-containing polyester resin particles according to any one of <1> to <4>, wherein

[0022] The acid value of the polyester resin is 1 mgKOH / g or more and 50 mgKOH / g or less.

[0023] <6>

[0024] A method for producing pigment-containing polyester resin particles, comprising producing the pigment-containing polyester resin particles according to any one of <1> to <5>, the method comprising the following steps:

[0025] applying heat and shear force to the polyester resin, the pigment, the alkaline compound, and the surfactant and mixing them to obtain a mixture in which the pigment is dispersed in the molten polyester resin; and

[0026] An aqueous medium is added to the mixture while applying a shear force to emulsify the mixture.

[0027] <7>

[0028] A method for producing pigment-containing polyester resin particles, comprising producing the pigment-containing polyester resin particles according to any one of <1> to <5>, the method comprising the following steps:

[0029] Applying heat and shear force to the polyester resin, the pigment and the organic solvent and mixing them to obtain a mixture in which the pigment is dispersed in the dissolved polyester resin; and

[0030] After adding the basic compound to the mixture, an aqueous medium is added while applying a shear force to emulsify the mixture.

[0031] <8>

[0032] A method for producing a toner for electrostatic latent image development comprises the following steps:

[0033] In a dispersion liquid containing the pigment-containing polyester resin particles described in any one of <1> to <5>, the pigment-containing polyester resin particles are agglomerated to form aggregated particles; and

[0034] The dispersion liquid containing the aggregated particles is heated to fuse the aggregated particles into a body, thereby forming toner particles.

[0035] <9>

[0036] A toner for developing an electrostatic latent image, comprising toner particles containing a polyester resin and a pigment,

[0037] In the toner particles, the number ratio of the pigment having a maximum Feret diameter of 250 nm or more is 20% by number or less.

[0038] <10>

[0039] An electrostatic latent image developer comprising the electrostatic latent image developing toner according to <9>.

[0040] <11>

[0041] A toner cartridge containing the electrostatic latent image developing toner described in <9>, and

[0042] Mounted on and removed from the image forming apparatus.

[0043] <12>

[0044] A process cartridge comprising a developing member that contains the electrostatic latent image developer described in <10> and develops the electrostatic latent image formed on the surface of an image holding member into a toner image using the electrostatic latent image developer,

[0045] The process cartridge is attachable to and detachable from the image forming apparatus.

[0046] <13>

[0047] An image forming device comprising:

[0048] Image holding body;

[0049] a charging member for charging the surface of the image holding member;

[0050] An electrostatic latent image forming member for forming an electrostatic latent image on the charged surface of the image holding member;

[0051] a developing member that contains the electrostatic latent image developer described in <10> and develops the electrostatic latent image formed on the surface of the image holding member into a toner image using the electrostatic latent image developer;

[0052] a transfer member that transfers the toner image formed on the surface of the image holding member to the surface of a recording medium; and

[0053] The fixing member fixes the toner image transferred to the surface of the recording medium.

[0054] <14>

[0055] An image forming method, comprising:

[0056] A charging process to charge the surface of the image holding body;

[0057] An electrostatic latent image forming step of forming an electrostatic latent image on the charged surface of the image holding member;

[0058] a developing step of developing the electrostatic latent image formed on the surface of the image holding member into a toner image using the electrostatic latent image developer described in <10>;

[0059] a transfer step of transferring the toner image formed on the surface of the image holding member to the surface of a recording medium; and

[0060] In the fixing step, the toner image transferred to the surface of the recording medium is fixed.

[0061] Effects of the Invention

[0062] According to <1>, there is provided a pigment-containing polyester resin particle having fewer coarse particles than a pigment-containing polyester resin particle in which the pigment is exposed on the surface of the pigment-containing polyester resin particle or inscribed in the outline of the pigment-containing polyester resin particle.

[0063] According to <2>, there is provided a pigment-containing polyester resin particle having fewer coarse particles than a pigment-containing polyester resin particle having a volume average particle size of less than 50 nm or more than 500 nm.

[0064] According to <3>, there is provided a pigment-containing polyester resin particle having a smaller number of coarse particles than a pigment-containing polyester resin particle having a pigment content of less than 10% by mass or more than 60% by mass.

[0065] According to <4>, there is provided a pigment-containing polyester resin particle having fewer coarse particles than a pigment-containing polyester resin particle having an average diameter of the pigment of less than 10 nm or exceeding 400 nm.

[0066] According to <5>, there is provided pigment-containing polyester resin particles having fewer coarse particles than pigment-containing polyester resin particles having an acid value of the polyester resin of less than 1 mgKOH / g or more than 50 mgKOH / g.

[0067] According to <6>, a method for producing pigment-containing polyester resin particles having a small amount of coarse particles is provided.

[0068] According to <7>, a method for producing pigment-containing polyester resin particles having a small amount of coarse particles is provided.

[0069] According to <8>, there is provided a method for producing a toner for developing an electrostatic latent image which has excellent low-temperature fixing property and is less likely to cause image unevenness.

[0070] According to <9>, a toner for developing an electrostatic latent image which is excellent in low-temperature fixing property and hardly causes image unevenness is provided.

[0071] According to <10>, an electrostatic latent image developer is provided which has excellent low-temperature fixing properties and is less likely to cause image unevenness.

[0072] According to <11>, there is provided a toner cartridge containing an electrostatic latent image developing toner having excellent low-temperature fixing properties and being less likely to cause image unevenness.

[0073] According to <12>, there is provided a process cartridge containing an electrostatic latent image developer which has excellent low-temperature fixing properties and is less likely to cause image unevenness.

[0074] According to <13>, an image forming apparatus is provided which has excellent low-temperature fixing properties and is less likely to cause image unevenness.

[0075] According to <14>, there is provided an image forming method which is excellent in low-temperature fixing property and is less likely to cause image unevenness. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0077] Figure 1 is a schematic structural diagram showing an image forming apparatus according to the present embodiment;

[0078] Figure 2 is a schematic structural diagram showing a process cartridge according to the present embodiment;

[0079] Figure 3 This is a schematic diagram of an image formed for evaluating image quality in the embodiment.

[0080] Explanation of symbols

[0081] 1Y, 1M, 1C, 1K-photoreceptor (an example of an image holding body), 2Y, 2M, 2C, 2K-charging roller (an example of a charging member), 3-exposure device (an example of an electrostatic latent image forming member), 3Y, 3M, 3C, 3K-laser beam, 4Y, 4M, 4C, 4K-developing device (an example of a developing member), 5Y, 5M, 5C, 5K-primary transfer roller (an example of a primary transfer member), 6Y, 6M, 6C, 6K-photoreceptor cleaning device (an example of a cleaning member), 8Y, 8M, 8C, 8K-toner cartridge, 10Y, 10M, 10C, 10K-image forming unit, 20-intermediate transfer belt (an example of an intermediate transfer body), 22-driving roller, 24-support roller, 26- Secondary transfer roller (an example of a secondary transfer component), 28-fixing device (an example of a fixing component), 30-intermediate transfer body cleaning device, P-recording paper (an example of a recording medium), 107-photosensitive body (an example of an image holding body), 108-charging roller (an example of a charging component), 109-exposure device (an example of an electrostatic latent image forming component), 111-developing device (an example of a developing component), 112-transfer device (an example of a transfer component), 113-photosensitive body cleaning device (an example of a cleaning component), 115-fixing device (an example of a fixing component), 116-mounting guide, 117-frame, 118-opening portion for exposure, 200-processing box, 300-recording paper (an example of a recording medium). DETAILED DESCRIPTION

[0082] Hereinafter, embodiments of the present invention will be described. These descriptions and examples are for illustrating the embodiments and do not limit the scope of the embodiments.

[0083] In the present invention, a numerical range expressed using "to" indicates a range including the numerical values ​​before and after "to" as the minimum value and the maximum value, respectively.

[0084] In the numerical ranges recorded in stages in the present invention, the upper limit or lower limit recorded in one numerical range can be replaced by the upper limit or lower limit of the numerical range recorded in other stages. And, in the numerical ranges recorded in the present invention, the upper limit or lower limit of the numerical range can be replaced by the value shown in the embodiment.

[0085] In the present invention, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes as long as the purpose of the process can be achieved.

[0086] When the embodiments of the present invention are described with reference to the drawings, the structure of the embodiments is not limited to the structure shown in the drawings. In addition, the sizes of the components in the drawings are conceptual, and the relative relationship between the sizes of the components is not limited thereto.

[0087] In the present invention, each component may contain a plurality of corresponding substances. When the amount of each component in the composition is mentioned in the present invention, when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of the plurality of substances present in the composition.

[0088] In the present invention, multiple types of particles corresponding to each component may be contained. When multiple types of particles corresponding to each component are present in the composition, unless otherwise specified, the particle size of each component represents a value for a mixture of the multiple types of particles present in the composition.

[0089] In the present invention, “(meth)acrylic acid” is an expression including both acrylic acid and methacrylic acid, and “(meth)acrylate” is an expression including both acrylate and methacrylate.

[0090] In the present invention, “toner” means “toner for electrostatic latent image development”, “developer” means “electrostatic latent image developer”, and “carrier” means “carrier for electrostatic latent image development”.

[0091] In the present invention, a method of producing toner particles by aggregating and combining material particles in a dispersion medium is referred to as an EA (Emulsion Aggregation) method.

[0092] <Pigment-containing polyester resin particles>

[0093] The pigment-containing polyester resin particles according to the present embodiment contain a polyester resin and a pigment, and the pigment is not exposed on the surface of the pigment-containing polyester resin particles and is not inscribed in the contour of the pigment-containing polyester resin particles.

[0094] That is, in the pigment contained in the pigment-containing polyester resin particles, the entire periphery of the pigment is covered with the polyester resin.

[0095] Therefore, the pigment-containing polyester resin particles according to the present embodiment suppress mutual aggregation of pigments and thus have fewer coarse particles.

[0096] The state of the pigment contained in the pigment-containing polyester resin particles was confirmed by the following method.

[0097] The pigment-containing polyester resin particles are mixed with an epoxy resin to embed the particles, and the epoxy resin is cured. When the pigment-containing polyester resin particles are in the form of a dispersion, the dispersion is dried to extract the pigment-containing polyester resin particles.

[0098] The cured product was cut by an ultra-thin slicer device (Ultracut UCT, Leica Corporation) to prepare a thin slice sample with a thickness of 100 nm. The cross section of the thin slice sample was observed at a magnification of 10,000 times using a field emission scanning electron microscope (FE-SEM, model: S-4800, Hitachi High-Technologies Corporation) to obtain a SEM image. The SEM image was read into the image analysis software ImageJ bundled with 32-bit Java 1.6.0_24ver ("Java" is a registered trademark), and after removing the noise in the image by the Despeckle process in the Process menu, it was analyzed and binarized under the condition of a brightness threshold of 50%, and the contours of the pigment particles present inside the pigment-containing polyester resin particles were extracted. There is no limitation on whether the pigment particles are primary particles or secondary particles. All resin particles and pigment particles within a field of view were observed to confirm whether there are pigment particles exposed from the outer edge of the resin particles (i.e., exposed) and whether there are pigment particles in contact with the outer edge of the resin particles (i.e., inscribed). The same operation is repeated until at least 100 resin particles are observed.

[0099] When the total number of resin particles in which pigment particles are exposed from the outer edge of the resin particles and the total number of resin particles in which the pigment particles are in contact with the outer edge of the resin particles is less than 5% of the total number of observed resin particles, it is determined that the pigment is not exposed on the surface of the pigment-containing polyester resin particles and is not inscribed in the outline of the pigment-containing polyester resin particles.

[0100] Conventionally, polyester resins and styrene acrylic resins have been commonly used as binder resins for toners. In general, polyester resins are superior to styrene acrylic resins in terms of low-temperature fixability of toners.

[0101] When the pigment-containing polyester resin particles according to the present embodiment are used, the polyester resin can be used as a main binder resin of the toner, and a toner having excellent low-temperature fixing properties can be produced.

[0102] Furthermore, when the pigment-containing polyester resin particles according to the present embodiment are used, coarse aggregates of the pigment contained in the toner particles can be suppressed, and the produced toner is less likely to cause image unevenness.

[0103] In the pigment-containing polyester resin particles according to the present embodiment, for example, the volume average particle diameter is preferably 50 nm or more and 500 nm or less.

[0104] If the volume average particle size of the pigment-containing polyester resin particles is 50 nm or more, the pigment is not easily exposed, so the pigment-containing polyester resin particles are not easily coarsely powdered. From this viewpoint, the volume average particle size of the pigment-containing polyester resin particles is, for example, more preferably 80 nm or more, and further preferably 100 nm or more.

[0105] If the volume average particle size of the pigment-containing polyester resin particles is 500 nm or less, the pigment in the pigment-containing polyester resin particles is not easy to aggregate. From this viewpoint, the volume average particle size of the pigment-containing polyester resin particles is, for example, more preferably 400 nm or less, and further preferably 300 nm or less.

[0106] The volume average particle size of the pigment-containing polyester resin particles refers to the particle size at which the cumulative total from the small diameter side reaches 50% in the particle size distribution measured by a laser diffraction particle size distribution analyzer (e.g., model: LS13-320, Beckman Coulter, Inc.). The number of particles measured is 10,000.

[0107] In the pigment-containing polyester resin particles according to the present embodiment, the content of the pigment is preferably, for example, 10% by mass or more and 60% by mass or less.

[0108] When the content of the pigment is 10% by mass or more, it is preferred, for example, in an image forming material. From this viewpoint, the content of the pigment is, for example, more preferably 12% by mass or more, and further preferably 15% by mass or more.

[0109] When the content of the pigment is 60% by mass or less, the pigment is not easily exposed, so the polyester resin particles containing the pigment are not easily coarsely powdered. From this viewpoint, the content of the pigment is, for example, more preferably 55% by mass or less, and further preferably 50% by mass or less.

[0110] In the pigment-containing polyester resin particles according to the present embodiment, the average diameter of the pigment is preferably, for example, not less than 10 nm and not more than 400 nm.

[0111] When the average diameter of the pigment is 10 nm or more, the pigment is less likely to aggregate. From this viewpoint, the average diameter of the pigment is, for example, more preferably 15 nm or more, and even more preferably 20 nm or more.

[0112] When the average diameter of the pigment is 400 nm or less, the pigment is not easily exposed, so the polyester resin particles containing the pigment are not easily coarsely powdered. From this viewpoint, the average diameter of the pigment is, for example, more preferably 300 nm or less, and further preferably 200 nm or less.

[0113] The average diameter of the pigment contained in the pigment-containing polyester resin particles is determined by the following method.

[0114] The pigment-containing polyester resin particles are mixed with an epoxy resin to embed the particles, and the epoxy resin is cured. When the pigment-containing polyester resin particles are in the form of a dispersion, the dispersion is dried to extract the pigment-containing polyester resin particles.

[0115] The cured product was cut by an ultra-thin slicer device (Ultracut UCT, Leica Corporation) to prepare a thin slice sample with a thickness of 100 nm. The cross section of the thin slice sample was observed at a magnification of 10,000 times using a field emission scanning electron microscope (FE-SEM, model: S-4800, Hitachi High-Technologies Corporation) to obtain a SEM image. The SEM image was read into the image analysis software ImageJ bundled with 32-bit Java 1.6.0_24ver ("Java" is a registered trademark), and after removing the noise in the image through the despeckle processing of the process menu, it was analyzed and binarized under the condition of a brightness threshold of 50%, and the contours of the pigment particles present inside the pigment-containing polyester resin particles were extracted. There is no limitation on whether the pigment particles are primary particles or secondary particles. The circular equivalent diameters of the contours of all pigment particles in a field of view were measured separately. The same operation was repeated until at least 100 pigment particles were measured. The arithmetic average of the measured circular equivalent diameters was taken as the average diameter of the pigment.

[0116] [pigment]

[0117] Examples of the pigment include organic pigments such as carbon black, chrome yellow, Hansa yellow, benzidine yellow, vat yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, magenta, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont Oil Red, pyrazolone red, litho red, rhodamine B lake, lake red C, pigment red, rose Bengal, aniline blue, histidine blue, copper oil blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate; and inorganic pigments such as titanium compounds and silica.

[0118] The pigment may be used alone or in combination of two or more.

[0119] The pigment may be a surface-treated pigment as required.

[0120] [Polyester resin]

[0121] As the polyester resin, there are amorphous polyester resins and crystalline polyester resins. As the polyester resin, only amorphous polyester resins may be used, only crystalline polyester resins may be used, or both amorphous polyester resins and crystalline polyester resins may be used. As the polyester resin, for example, amorphous polyester resins are preferred.

[0122] The acid value of the polyester resin is preferably, for example, 1 mgKOH / g or more and 50 mgKOH / g or less.

[0123] If the acid value of the polyester resin is 1 mgKOH / g or more, the viscosity of the resin composition will not become too low when manufacturing the polyester resin particles containing the pigment, and the pigment can be easily taken into the polyester resin particles containing the pigment. From this viewpoint, the acid value of the polyester resin is, for example, more preferably 5 mgKOH or more, and further preferably 10 mgKOH or more.

[0124] If the acid value of the polyester resin is 50 mgKOH / g or less, the viscosity of the resin composition will not become too high when manufacturing the polyester resin particles containing the pigment, and the pigment can be easily taken into the polyester resin particles containing the pigment. From this viewpoint, the acid value of the polyester resin is, for example, more preferably 45 mgKOH or less, and further preferably 40 mgKOH or less.

[0125] The acid value of the polyester resin is determined by a titration method specified in JIS K0070-1992 using an appropriate amount of the polyester resin as a sample.

[0126] -Amorphous polyester resin-

[0127] As the amorphous polyester resin, a commercially available product may be used, or a synthetic product may be used.

[0128] Examples of the non-crystalline polyester resin include polycondensates of polycarboxylic acids and polyols.

[0129] Examples of the polycarboxylic acid as a polymer component of the amorphous polyester resin include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (e.g., cyclohexane dicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, etc.), and anhydrides thereof or lower (e.g., carbon number 1 to 5) alkyl esters thereof. Among these, aromatic dicarboxylic acids are preferred as the polycarboxylic acid.

[0130] The polycarboxylic acid may be used together with the dicarboxylic acid in a trivalent or higher carboxylic acid having a cross-linked structure or a branched structure. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, their anhydrides, or their lower (e.g., carbon number 1 to 5) alkyl esters.

[0131] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0132] Examples of the polyol as a polymerization component of the amorphous polyester resin include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-docosanediol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), and aromatic diols (e.g., ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, as the polyol, for example, aliphatic diol is preferable.

[0133] As the polyol as the polymerization component of the amorphous polyester resin, a trivalent or higher polyol having a crosslinked structure or a branched structure may be used together with a diol. Examples of the trivalent or higher polyol include glycerol, trimethylolpropane, and pentaerythritol.

[0134] The polyols may be used alone or in combination of two or more.

[0135] The glass transition temperature (Tg) of the amorphous polyester resin is, for example, preferably 50°C to 75°C, more preferably 50°C to 70°C, and further preferably 50°C to 65°C.

[0136] The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), more specifically, according to the "extrapolated glass transition start temperature" described in the method for determining the glass transition temperature in JIS K7121-1987 "Determination of Transition Temperature of Plastics".

[0137] The weight average molecular weight (Mw) of the amorphous polyester resin is, for example, preferably 5,000 or more and 1,000,000 or less, and more preferably 7,000 or more and 500,000 or less.

[0138] The number average molecular weight (Mn) of the amorphous polyester resin is preferably, for example, 2,000 or more and 100,000 or less.

[0139] The molecular weight distribution Mw / Mn of the amorphous polyester resin is, for example, preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less.

[0140] The weight average molecular weight and the number average molecular weight are measured by gel permeation chromatography (GPC). In the molecular weight measurement by GPC, GPC HLC-8120GPC manufactured by TOSOH CORPORATION is used as a measuring device, and a column TSKgel SuperHM-M (15 cm) manufactured by TOSOH CORPORATION is used, and the solvent is THF. The weight average molecular weight and the number average molecular weight are calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample based on the measurement results.

[0141] The amorphous polyester resin is obtained by a known production method. Specifically, for example, the amorphous polyester resin is obtained by setting the polymerization temperature to 180° C. to 230° C., reducing the pressure in the reaction system as necessary, and reacting while removing water and alcohol generated during condensation.

[0142] When the monomer of the raw material is insoluble or incompatible at the reaction temperature, a high boiling point solvent can be added as a cosolvent to dissolve it. In this case, the polycondensation reaction is carried out while the cosolvent is removed by distillation. When there are monomers with poor compatibility in the copolymerization reaction, for example, the monomers with poor compatibility can be condensed in advance with an acid or alcohol to be polycondensed with the monomer, and then polycondensed with the main component.

[0143] -Crystalline polyester resin-

[0144] As the crystalline polyester resin, a commercially available product may be used, or a synthetic product may be used.

[0145] Examples of the crystalline polyester resin include polycondensates of polycarboxylic acids and polyols. Since the crystalline polyester resin easily forms a crystalline structure, for example, a polycondensate of a linear aliphatic polymerizable monomer is preferably used rather than a polycondensate of a polymerizable monomer having an aromatic ring.

[0146] Examples of the polycarboxylic acid as a superposed component of the crystalline polyester resin include aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalene-2,6-dicarboxylic acid, etc.), their anhydrides, or their lower (e.g., carbon number 1 to 5) alkyl esters.

[0147] The polycarboxylic acid may be used together with the dicarboxylic acid and a trivalent or higher carboxylic acid having a cross-linked structure or a branched structure. Examples of the trivalent carboxylic acid include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), their anhydrides, or their lower (e.g., carbon number 1 to 5) alkyl esters.

[0148] As the polycarboxylic acid, a dicarboxylic acid having a sulfonic acid group or a dicarboxylic acid having an ethylenic double bond may be used together with these dicarboxylic acids.

[0149] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0150] Examples of the polyol as a polymerization component of the crystalline polyester resin include aliphatic diols (e.g., linear aliphatic diols having a main chain portion with carbon atoms of 7 or more and 20 or less). Examples of the aliphatic diols include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-docosanediol.

[0151] As the polyol of the polymerization component of the crystalline polyester resin, a trivalent or higher alcohol having a cross-linked structure or a branched structure may be used together with the diol. Examples of the trivalent or higher alcohol include glycerol, trimethylolethane, trimethylolpropane, pentaerythritol, and the like.

[0152] The polyols may be used alone or in combination of two or more.

[0153] The melting temperature of the crystalline polyester resin is, for example, preferably 50° C. or higher and 100° C. or lower, more preferably 55° C. or higher and 90° C. or lower, and further preferably 60° C. or higher and 85° C. or lower.

[0154] The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) in accordance with the “melting peak temperature” described in the method for determining the melting temperature in JIS K7121-1987 “Determination of Transition Temperatures of Plastics”.

[0155] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably, for example, 6,000 or more and 35,000 or less.

[0156] Similar to the amorphous polyester resin, the crystalline polyester resin can be obtained by, for example, a known production method.

[0157] <Method for producing pigment-containing polyester resin particles>

[0158] The pigment-containing polyester resin particles are preferably produced in the form of a dispersion containing the particles, for example. That is, the production process of the pigment-containing polyester resin particles is preferably a production process of a pigment-containing polyester resin particle dispersion, for example.

[0159] From the viewpoint of allowing the toner particles to contain a sufficient amount of pigment, the solid content concentration of the pigment-containing polyester resin particle dispersion is, for example, preferably 10 mass % or more, more preferably 15 mass % or more, and further preferably 20 mass % or more.

[0160] From the viewpoint of dispersibility of the particles, the solid content concentration of the pigment-containing polyester resin particle dispersion is, for example, preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less.

[0161] Specifically, the pigment-containing polyester resin particles are preferably produced, for example, by "solvent-free emulsification" or "solvent emulsification" as described below. "Solvent-free emulsification" and "solvent emulsification" produce a dispersion of pigment-containing polyester resin particles.

[0162] In "solvent-free emulsification" or "solvent emulsification", for example, by controlling the operating conditions of the device and / or the amount of material used, the entire periphery of the pigment can be coated with the polyester resin, and the volume average particle size of the pigment-containing polyester resin particles, the pigment content, the average diameter of the pigment, etc. can be controlled within a preferred range.

[0163] [Solvent-free emulsification]

[0164] Solvent-free emulsification is a method of producing a resin particle dispersion without using an organic solvent.

[0165] Specifically, solvent-free emulsification includes the following steps:

[0166] The polyester resin, the pigment, the alkaline compound and the surfactant are mixed by applying heat and shear force to obtain a mixture in which the pigment is dispersed in the molten polyester resin (melting step); and an aqueous medium is added to the mixture while applying shear force to emulsify the mixture (emulsification step).

[0167] For example, the solvent-free emulsification preferably uses a mixing extruder to perform the melting process and the emulsification process. The mixing extruder is a device that continuously conveys the processed material while applying heat and shear force to the processed material. Generally speaking, the structure of the mixing extruder is roughly divided into a material input port, a barrel, and a mold from upstream to downstream. A screw is provided inside the barrel. A heater for heating the inside of the barrel is provided around the barrel. The screw can be a single screw type or a twin screw type, and is preferably a twin screw type.

[0168] - Melting process -

[0169] The melting step is a step of applying heat and shear force to the polyester resin, the pigment, the basic compound, and the surfactant to mix them and obtain a mixture in which the pigment is dispersed in the molten polyester resin.

[0170] As the alkaline compound, for example, sodium hydroxide or potassium hydroxide is preferred. From the viewpoint of uniformity of kneading, sodium hydroxide or potassium hydroxide is preferably used in the form of an aqueous solution (ie, a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution).

[0171] The amount of the basic compound used is an amount that enables emulsification and dispersion of the mixture. Specifically, the amount of the basic compound used is preferably an amount such that the neutralization rate based on the following formula (1) is 20% or more and 60% or less.

[0172] Formula (1): Neutralization rate (%) = mb × n × 56.1 ÷ Mwb ÷ AV × 1000,

[0173] mb is the amount of the basic compound used per 1g of polyester resin (g),

[0174] n is the valence of the basic compound,

[0175] Mwb is the molecular weight of the basic compound,

[0176] AV is the acid value of the polyester resin (mgKOH / g).

[0177] The surfactant may be any of anionic surfactants, cationic surfactants, and nonionic surfactants. For example, anionic surfactants such as sulfate ester salts, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyols; etc. Surfactants may be used alone or in combination of two or more. Nonionic surfactants may be used together with anionic surfactants or cationic surfactants.

[0178] The amount of the surfactant used is set to an amount that allows the emulsified particles to maintain dispersion.

[0179] -Emulsification process-

[0180] The emulsification step is a step of emulsifying a mixture in which a pigment is dispersed in a molten polyester resin by adding an aqueous medium while applying a shear force.

[0181] As the aqueous medium, for example, water with reduced ion content such as distilled water or deionized water is preferred. The aqueous medium is preferably used after adjusting the temperature to within the range of ±5°C of the internal temperature of the barrel of the kneading extruder.

[0182] In the melting step, the temperature inside the barrel of the kneading extruder is, for example, preferably 80° C. or higher and 100° C. or lower, more preferably 85° C. or higher and 97° C. or lower, and further preferably 90° C. or higher and 95° C. or lower.

[0183] In the emulsification step, the temperature inside the barrel of the kneading extruder is, for example, preferably 80° C. to 100° C., more preferably 85° C. to 97° C., and further preferably 90° C. to 95° C.

[0184] [Solvent emulsification]

[0185] Specifically, solvent emulsification includes the following steps:

[0186] The polyester resin, the pigment and the organic solvent are mixed by applying heat and shear force to obtain a mixture in which the pigment is dispersed in the dissolved polyester resin (dissolution step); and after adding a basic compound to the mixture, an aqueous medium is added while applying shear force to emulsify it (emulsification step).

[0187] The solvent emulsification is preferably carried out in a stirring tank having a stirring member and a heating and cooling member. The stirring member is preferably a stirring member having a rotating shaft and stirring blades. The heating and cooling member is preferably a member that applies and / or removes heat from the wall of the stirring tank.

[0188] -Dissolution process-

[0189] The dissolving step is a step of applying heat and shear force to the polyester resin, the pigment, and the organic solvent to mix them and obtain a mixture in which the pigment is dispersed in the dissolved polyester resin.

[0190] Examples of the organic solvent capable of dissolving the polyester resin include ethyl acetate, isopropyl alcohol, 2-butanol, and mixed solvents thereof, of which an organic solvent or mixed solvent having a boiling point of 60° C. or higher and less than 100° C. is preferred.

[0191] -Emulsification process-

[0192] The emulsification step is a step of adding a basic compound to the mixture and then adding an aqueous medium while applying a shear force, so that the mixture is emulsified and dispersed in the aqueous medium in the form of particles.

[0193] As the basic compound, for example, aqueous ammonia is preferred.

[0194] The amount of the basic compound used is an amount that enables emulsification and dispersion of the mixture. Specifically, the amount of the basic compound used is preferably an amount such that the neutralization rate based on the following formula (1) is 70% or more and 100% or less.

[0195] Formula (1): Neutralization rate (%) = mb × n × 56.1 ÷ Mwb ÷ AV × 1000,

[0196] mb is the amount of the basic compound used per 1g of polyester resin (g),

[0197] n is the valence of the basic compound,

[0198] Mwb is the molecular weight of the basic compound,

[0199] AV is the acid value of the polyester resin (mgKOH / g).

[0200] The aqueous medium is preferably water with reduced ion content such as distilled water or deionized water. The aqueous medium is preferably used at a temperature adjusted to a range of 35° C. to 100° C. (for example, preferably 35° C. to 55° C.).

[0201] In the dissolving step, the temperature of the object to be treated contained in the stirring tank is, for example, preferably 20°C to 50°C, more preferably 23°C to 45°C, and further preferably 25°C to 40°C.

[0202] In the emulsification step, the temperature of the treated material contained in the stirring tank is, for example, preferably 20°C to 50°C, more preferably 23°C to 45°C, and further preferably 25°C to 40°C.

[0203] The method of adding the aqueous medium in the emulsification step is preferably dropwise addition, for example.

[0204] After the addition of the aqueous medium is completed, for example, preferably the inside of the stirred tank is decompressed and / or the emulsion is bubbled to remove the organic solvent. Then, in order to improve the dispersion stability of the particles, a surfactant can be added. As the surfactant, the above-mentioned anionic surfactant, cationic surfactant, and nonionic surfactant can be enumerated.

[0205] <Method for producing toner for developing electrostatic latent images>

[0206] The method for producing a toner according to the present embodiment includes a step of producing toner particles by the EA method.

[0207] In the method for producing a toner according to the present embodiment, at least polyester resin particles containing a pigment are used as material particles.

[0208] Therefore, the method for producing a toner according to the present embodiment includes the step of aggregating and combining material particles including polyester resin particles containing a pigment in a dispersion medium to obtain toner particles.

[0209] Specifically, the method for producing a toner according to the present embodiment includes the following steps:

[0210] Aggregating the pigment-containing polyester resin particles in a dispersion containing the pigment-containing polyester resin particles according to the present embodiment to form aggregated particles; and

[0211] The dispersion liquid containing the aggregated particles is heated to fuse the aggregated particles into a body, thereby forming toner particles.

[0212] Hereinafter, each step and material of the EA method in this embodiment will be described in detail.

[0213] [Aggregation step (first aggregating step)]

[0214] The aggregation step is a step of aggregating the material particles in the dispersion liquid containing the material particles to form aggregated particles.

[0215] When the toner production method according to the present embodiment includes the second aggregation step (a step for forming a shell) described below, the aggregation step is referred to as a “first aggregation step.” The first aggregation step is a step for forming a core in a toner having a core / shell structure.

[0216] The dispersion liquid supplied to the aggregation step contains at least polyester resin particles containing a pigment. The dispersion liquid supplied to the aggregation step preferably further contains, for example, binder resin particles and release agent particles.

[0217] The dispersions to be used in the aggregation step are prepared by, for example, separately preparing a pigment-containing polyester resin particle dispersion, a binder resin particle dispersion, and a release agent particle dispersion, and mixing these particle dispersions. The order of mixing these particle dispersions is not limited.

[0218] Hereinafter, the common points between the binder resin particle dispersion and the release agent particle dispersion are collectively referred to as “particle dispersion” for explanation.

[0219] An example of an embodiment of the particle dispersion is a dispersion in which a material is dispersed in a dispersion medium in the form of particles by a surfactant.

[0220] As the dispersion medium of the particle dispersion, for example, an aqueous medium is preferred. As the aqueous medium, for example, water and alcohol can be cited. As for water, for example, distilled water, deionized water and other water with reduced ion content are preferred. These aqueous media can be used alone or in combination of two or more.

[0221] The surfactant that disperses the material in the dispersion medium may be any of anionic surfactants, cationic surfactants, and nonionic surfactants. For example, anionic surfactants such as sulfate ester salts, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyols; etc. Surfactants may be used alone or in combination of two or more. Nonionic surfactants may be used together with anionic surfactants or cationic surfactants.

[0222] Examples of a method for dispersing the material in a dispersion medium in a particle form include known dispersion methods such as a rotary shearing homogenizer, a ball mill equipped with a medium, a sand mill, and a DYNO-MILL.

[0223] As a method for dispersing the resin in a dispersion medium in the form of particles, a phase inversion emulsification method can be cited. An example of the phase inversion emulsification method is a method in which a resin is dissolved in a hydrophobic organic solvent that can dissolve the resin, a basic compound is added to an organic continuous phase (O phase), and then an aqueous medium (W phase) is added to perform a phase inversion from W / O to O / W, thereby dispersing the resin in the form of particles in the aqueous medium.

[0224] The volume average particle size of the particles dispersed in the particle dispersion is, for example, preferably 30 nm to 300 nm, more preferably 50 nm to 250 nm, and further preferably 80 nm to 200 nm.

[0225] The volume average particle size of particles in the particle dispersion is the particle size at 50% cumulatively from the small diameter side in the particle size distribution measured by a laser diffraction particle size distribution analyzer (e.g., model: LS13-320, Beckman Coulter, Inc.) The number of particles measured is 10,000.

[0226] The content of the particles contained in the particle dispersion is, for example, preferably 5 mass % to 50 mass %, more preferably 10 mass % to 40 mass %, and further preferably 15 mass % to 30 mass %.

[0227] Hereinafter, the materials constituting the particles of each of the binder resin particle dispersion and the release agent particle dispersion will be described.

[0228] -Bonding resin-

[0229] Examples of the binder resin include vinyl resins composed of homopolymers of monomers such as styrenes (e.g., styrene, p-chlorostyrene, α-methylstyrene, etc.), (meth)acrylates (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (e.g., ethylene, propylene, butadiene, etc.), or copolymers of two or more of these monomers.

[0230] Examples of the binder resin include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosins, and mixtures thereof with the vinyl resins or graft polymers obtained by polymerizing vinyl monomers under the coexistence of the non-vinyl resins.

[0231] These binder resins may be used alone or in combination of two or more.

[0232] As the binder resin, for example, a polyester resin is preferred. As the polyester resin, a non-crystalline polyester resin and a crystalline polyester resin can be mentioned. As the polyester resin, only a non-crystalline polyester resin can be used, only a crystalline polyester resin can be used, or both a non-crystalline polyester resin and a crystalline polyester resin can be used.

[0233] When an amorphous polyester resin is used in producing the pigment-containing polyester resin particles, for example, it is preferred that the binder resin contain an amorphous polyester resin having the same form as that of the amorphous polyester resin.

[0234] When a crystalline polyester resin is used in producing the pigment-containing polyester resin particles, for example, it is preferred that the binder resin contain a crystalline polyester resin having the same form as that of the crystalline polyester resin.

[0235] -Release agent-

[0236] Examples of the release agent include hydrocarbon waxes, natural waxes such as carnauba wax, rice wax, and candelilla wax, synthetic waxes such as montan wax, or mineral / petroleum waxes, and ester waxes such as fatty acid esters and montanic acid esters. The release agent is not limited thereto.

[0237] The melting temperature of the release agent is, for example, preferably 50° C. or higher and 110° C. or lower, and more preferably 60° C. or higher and 100° C. or lower.

[0238] The melting temperature of the release agent is determined from a DSC curve obtained by differential scanning calorimetry (DSC) based on the "melting peak temperature" described in the method for determining the melting temperature in JIS K7121:1987 "Determination of Transition Temperatures of Plastics".

[0239] Hereinafter, a dispersion obtained by mixing a plurality of types of particle dispersions will be referred to as a "mixed dispersion".

[0240] The mass ratio of the particles contained in the mixed dispersion is preferably in the following range, for example.

[0241] The mass ratio of the binder resin particles to the pigment-containing polyester resin particles is, for example, preferably binder resin particles:pigment-containing polyester resin particles=100:1 to 100:100, more preferably 100:2 to 100:60, and even more preferably 100:5 to 100:40.

[0242] The mass ratio of the binder resin particles to the release agent particles is, for example, preferably binder resin particles:release agent particles=100:1 to 100:40, more preferably 100:2 to 100:30, and even more preferably 100:5 to 100:20.

[0243] After mixing the plurality of particle dispersions, the pH of the mixed dispersion is preferably adjusted to, for example, 3 to 4. Examples of methods for adjusting the pH of the mixed dispersion include adding an acidic aqueous solution such as nitric acid, hydrochloric acid, or sulfuric acid.

[0244] The aggregation process includes, for example, the following steps:

[0245] adding a coagulant to the mixed dispersion while stirring the mixed dispersion; and

[0246] After the coagulant is added to the mixed dispersion, the mixed dispersion is heated while stirring the mixed dispersion to increase the temperature of the mixed dispersion.

[0247] Examples of the coagulant include a surfactant having a polarity opposite to that of the surfactant contained in the mixed dispersion, an inorganic metal salt, and a divalent or higher-valent metal complex. The coagulant may be used alone or in combination of two or more.

[0248] Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide; and the like.

[0249] The coagulant is preferably a divalent or higher metal salt compound, more preferably a trivalent metal salt compound, and still more preferably a trivalent inorganic aluminum salt compound. Examples of the trivalent inorganic aluminum salt compound include aluminum chloride, aluminum sulfate, polyaluminum chloride, and polyaluminum hydroxide.

[0250] The amount of the coagulant added is not limited. When a trivalent metal salt compound is used as a coagulant, the amount of the trivalent metal salt compound added is, for example, preferably 0.01 parts by mass or more and 10 parts by mass or less, more preferably 0.05 parts by mass or more and 5 parts by mass or less, and further preferably 0.1 parts by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0251] The temperature reached when the mixed dispersion is heated is preferably a temperature based on the glass transition temperature (Tg) of the binder resin particles, for example, not less than (Tg-30°C) and not more than (Tg°C) of the binder resin particles.

[0252] When the mixed dispersion contains a plurality of types of binder resin particles having different Tgs, the lowest temperature among the respective Tgs is defined as the Tg in the aggregation step.

[0253] [Second Aggregation Step]

[0254] The second aggregation step is a step provided for the purpose of producing a toner having a core / shell structure and is a step provided after the first aggregation step. The second aggregation step is a step for forming a shell.

[0255] The second aggregation step is a step of mixing a dispersion containing aggregated particles and a dispersion containing resin particles that serve as shells, and aggregating the resin particles that serve as shells on the surfaces of the aggregated particles to form second aggregated particles.

[0256] The dispersion containing the resin particles that serve as the shell is preferably at least one selected from the dispersions of binder resin particles that serve to form the core, more preferably a dispersion of polyester resin particles, and still more preferably an amorphous polyester resin particle dispersion.

[0257] The second coagulation step includes, for example, the following steps:

[0258] adding a dispersion containing resin particles that serve as shells to the dispersion containing the aggregated particles while stirring the dispersion containing the aggregated particles; and

[0259] The dispersion containing the aggregated particles to which the dispersion containing the resin particles serving as the shells has been added is heated while being stirred.

[0260] The temperature reached when the dispersion containing aggregated particles is heated is preferably a temperature based on the glass transition temperature (Tg) of the resin particles forming the shell, for example, (Tg-30°C) or higher and (Tg-10°C) or lower.

[0261] After the aggregated particles or second aggregated particles grow to a predetermined size and before the heating in the combining step, a chelating agent for the aggregating agent used in the aggregating step may be added to the dispersion containing the aggregated particles or second aggregated particles in order to stop the growth of the aggregated particles or second aggregated particles.

[0262] Examples of the chelating agent include hydroxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid; aminocarboxylic acids such as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA); and the like.

[0263] The amount of the chelating agent added is, for example, preferably 0.01 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass, relative to 100 parts by mass of the binder resin particles.

[0264] After the aggregated particles or second aggregated particles grow to a predetermined size, the pH of the dispersion containing the aggregated particles or second aggregated particles may be increased for the purpose of stopping the growth of the aggregated particles or second aggregated particles before heating in the combining step.

[0265] Examples of a method for increasing the pH of the dispersion containing aggregated particles or second aggregated particles include adding at least one selected from the group consisting of an aqueous solution of an alkali metal hydroxide and an aqueous solution of an alkaline earth metal hydroxide.

[0266] The ultimate pH of the dispersion containing the aggregated particles or the second aggregated particles is preferably, for example, 8 or more and 10 or less.

[0267] [Combination process]

[0268] The agglomeration step is a step of heating the dispersion liquid containing the aggregated particles to fuse the aggregated particles into a body to form toner particles.

[0269] When the second aggregation step is provided before the combining step, the combining step is a step of heating the dispersion containing the second aggregated particles to fuse the second aggregated particles to form toner particles. By going through the second aggregation step and the combining step, toner particles with a core / shell structure can be produced.

[0270] The aspects described below are common to the aggregated particles and the second aggregated particles.

[0271] The reaching temperature of the dispersion containing the aggregated particles is preferably, for example, not less than the glass transition temperature (Tg) of the binder resin, and specifically, preferably a temperature 10° C. to 30° C. higher than the Tg of the binder resin.

[0272] When the aggregated particles contain a plurality of binder resins having different Tgs, the highest temperature among the respective Tgs is defined as the glass transition temperature in the combining step.

[0273] After the combination process is completed, the toner particles in the dispersion are subjected to a known washing process, a solid-liquid separation process, and a drying process to obtain dry toner particles. From the perspective of chargeability, the washing process is preferably performed by, for example, fully performing replacement washing with deionized water. From the perspective of productivity, the solid-liquid separation process is preferably performed by, for example, suction filtration, pressure filtration, etc. From the perspective of productivity, the drying process is preferably performed by, for example, freeze drying, airflow drying, fluidized bed drying, vibration-type fluidized bed drying, etc.

[0274] [Process of adding external additives]

[0275] The method for producing a toner according to the present embodiment preferably includes, for example, a step of adding an external additive to toner particles.

[0276] The external additive is added to the toner particles by mixing the toner particles in a dry state with the external additive. The mixing is performed, for example, by a V mixer, a Henschel mixer, a Lödige mixer, etc. Furthermore, coarse particles of the toner may be removed by using a vibration sieving machine, a wind sieving machine, etc. as needed.

[0277] Examples of external additives include inorganic particles. Examples of inorganic particles include SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2) n , Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, etc.

[0278] For the surface of the inorganic particles as an external additive, for example, a hydrophobic treatment is preferably implemented. The hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic treatment agent. The hydrophobic treatment agent is not particularly limited, and for example, a silane coupling agent, silicone oil, a titanate coupling agent, an aluminum coupling agent, etc. can be cited. They can be used alone or in combination of two or more.

[0279] Usually, the amount of the hydrophobizing agent is, for example, 1 part by mass or more and 10 parts by mass or less relative to 100 parts by mass of the inorganic particles.

[0280] Examples of the external additives include resin particles (polystyrene, polymethyl methacrylate, melamine resin, and other resin particles), cleaning aids (for example, metal salts of higher fatty acids such as zinc stearate, and particles of fluorine-based high molecular weight bodies), and the like.

[0281] The amount of the external additive added is, for example, preferably 0.01% by mass or more and 5% by mass or less, and more preferably 0.01% by mass or more and 2% by mass or less, relative to the mass of the toner particles.

[0282] <Toner for electrostatic latent image development>

[0283] The toner according to the present embodiment includes at least toner particles. The toner according to the present embodiment preferably includes, for example, toner particles and an external additive.

[0284] The toner according to the present embodiment includes toner particles containing a polyester resin and a pigment, and the number ratio of the pigment having a maximum Feret diameter of 250 nm or more in the toner particles is 20% by number or less.

[0285] Regarding the pigment inside the toner particles, a maximum Feret diameter of 250 nm is an indicator of aggregation, and “a pigment having a maximum Feret diameter of 250 nm or more” means an undesirable aggregate.

[0286] In the toner according to the present embodiment, since the number ratio of pigment particles having a maximum Feret diameter of 250 nm or more is 20% by number or less of the total number of pigment particles, the toner has excellent low-temperature fixing properties and is less likely to cause image unevenness.

[0287] The number ratio of the pigments having a Feret diameter of 250 nm or more is, for example, more preferably 15% by number or less, further preferably 10% by number or less, and most preferably 0% by number.

[0288] The maximum Feret diameter of the pigment contained in the toner particles is measured by the following method.

[0289] The toner is mixed with the epoxy resin and embedded therein to cure the epoxy resin. The cured product is cut by an ultra-thin slicer device (Ultracut UCT, Leica Corporation) to prepare a thin slice sample with a thickness of 100 nm. The cross section of the thin slice sample is observed at a magnification of 10,000 times using a field emission scanning electron microscope (FE-SEM, model: S-4800, Hitachi High-Technologies Corporation) to obtain a SEM image. The SEM image is read into the image analysis software ImageJbundled with 32-bit Java1.6.0_24ver ("Java" is a registered trademark), and after removing the noise in the image through the despeckle processing of the process menu, it is analyzed and binarized under the condition of a brightness threshold of 50%, and the contours of the pigment particles present in the toner particles are extracted. There is no limitation on whether the pigment particles are primary particles or secondary particles. For the contours of all pigment particles present in the toner particles, the maximum Feret diameter is measured respectively. The same operation is performed on 100 toner particles. The distribution of the maximum Feret diameter was divided into 50 nm units within the range of 10 nm to 2000 nm, and the number ratio (number %) of pigments having a maximum Feret diameter of 250 nm or more was determined.

[0290] The total content of the polyester resin is, for example, preferably 40 mass % to 95 mass % inclusive, more preferably 50 mass % to 90 mass % inclusive, and further preferably 60 mass % to 85 mass % inclusive, based on the entire toner.

[0291] When the toner particles contain a crystalline polyester resin, the content of the crystalline polyester resin is, for example, preferably 3% by mass or more and 30% by mass or less, and more preferably 8% by mass or more and 20% by mass or less, based on the total binder resin.

[0292] When the toner contains a releasing agent, the content of the releasing agent is, for example, preferably 1 mass % or more and 20 mass % or less, and more preferably 5 mass % or more and 15 mass % or less, based on the entire toner.

[0293] The content of the pigment is, for example, preferably 1 mass % or more and 30 mass % or less, and more preferably 3 mass % or more and 15 mass % or less, based on the entire toner.

[0294] The toner particles may be toner particles of a single-layer structure, or may be toner particles of a so-called core / shell structure composed of a core (core particle) and a coating layer (shell layer) that covers the core.

[0295] The volume average particle diameter (D50v) of the toner particles is, for example, preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

[0296] The average particle size of the toner particles is measured using Coulter Multisizer II (manufactured by Beckman Coulter, Inc.) and ISOTON-II (manufactured by Beckman Coulter, Inc.) for the electrolyte. Add 0.5 mg or more and 50 mg or less of the measurement sample to 2 ml of a 5% by mass aqueous solution of a surfactant (for example, preferably sodium alkylbenzene sulfonate), and add it to 100 ml or more and 150 ml or less of the electrolyte. The electrolyte to which the sample is added is dispersed for 1 minute by an ultrasonic disperser, and the particle size is measured in the range of 2 μm or more and 60 μm or less by Coulter Multisizer II using a hole with an aperture of 100 μm. The number of particles measured is 50,000. Based on the measured particle size distribution, the volume distribution or the number distribution is plotted from the smaller diameter side, and the particle size when accumulated to 50% is taken as the volume average particle size D50v or the number average particle size D50p.

[0297] The average circularity of the toner particles is, for example, preferably 0.94 or more and 1.00 or less, and more preferably 0.95 or more and 0.98 or less.

[0298] The average circularity of the toner particles is the average of (circle equivalent circumference) / (circumference)=(circumference of a circle having the same area as the projected area of ​​the particle) / (circumference of the projected image of the particle).

[0299] As a particle image measuring machine, a flow particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation) was used. The number of toner particles measured was 3500. In the case where the toner has an external additive, the toner is dispersed in water containing a surfactant and subjected to ultrasonic treatment to obtain toner particles after the external additive is removed.

[0300] Examples of external additives include inorganic particles. Examples of inorganic particles include SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2) n , Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, etc.

[0301] The surface of the inorganic particles as an external additive is preferably subjected to hydrophobic treatment. The hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic treatment agent. The hydrophobic treatment agent is not particularly limited, and for example, silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents, etc. can be cited. They can be used alone or in combination of two or more. The amount of the hydrophobic treatment agent is, for example, 1 part by mass or more and 10 parts by mass or less relative to 100 parts by mass of the inorganic particles.

[0302] Examples of the external additives include resin particles (polystyrene, polymethyl methacrylate, melamine resin, and other resin particles), cleaning aids (for example, metal salts of higher fatty acids such as zinc stearate, and particles of fluorine-based high molecular weight bodies), and the like.

[0303] The amount of the external additive added is, for example, preferably 0.01% by mass or more and 5% by mass or less, and more preferably 0.01% by mass or more and 2% by mass or less, based on the toner particles.

[0304] <Electrostatic latent image developer>

[0305] The electrostatic latent image developer according to the present embodiment contains at least the toner according to the present embodiment.

[0306] The electrostatic latent image developer according to the present embodiment may be a single-component developer containing only the toner according to the present embodiment, or may be a two-component developer in which the toner and a carrier are mixed.

[0307] The carrier is not particularly limited, and known carriers may be used. Examples of the carrier include a coated carrier in which the surface of a core material composed of magnetic powder is coated with a resin; a magnetic powder dispersed carrier in which magnetic powder is dispersed in a matrix resin; a resin impregnated carrier in which porous magnetic powder is impregnated with a resin; and the like.

[0308] The magnetic powder dispersed carrier and the resin impregnated carrier may be a carrier having constituent particles of the carrier as a core material and the surface of the core material coated with a resin.

[0309] Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt; magnetic oxides such as ferrite and magnetite; and the like.

[0310] As the coating resin and the matrix resin, for example, polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylate copolymer, a straight-chain silicone resin containing an organic siloxane bond or a modified product thereof, a fluororesin, a polyester, a polycarbonate, a phenolic resin, an epoxy resin, etc. can be cited. The coating resin and the matrix resin may contain other additives such as conductive particles. As the conductive particles, particles such as metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate can be cited.

[0311] In order to coat the surface of the core material with resin, the coating layer formed by dissolving the coating resin and various additives (using as required) in a suitable solvent can be enumerated to coat with a solution. As solvent, there is no particular limitation, as long as the type of the resin used and coating suitability etc. are considered to be selected.

[0312] Specific resin coating methods include an immersion method in which the core material is immersed in a coating layer forming solution; a spraying method in which the coating layer forming solution is sprayed on the surface of the core material; a fluidized bed method in which the coating layer forming solution is sprayed while the core material is suspended by flowing air; a kneading coating method in which the core material of the carrier and the coating layer forming solution are mixed in a kneading coater and then the solvent is removed; and the like.

[0313] The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is, for example, preferably toner:carrier=1:100 to 30:100, and more preferably 3:100 to 20:100.

[0314] <Image forming apparatus and image forming method>

[0315] An image forming apparatus and an image forming method according to the present embodiment will be described.

[0316] The image forming apparatus according to the present embodiment comprises: an image holder; a charging member for charging the surface of the image holder; an electrostatic latent image forming member for forming an electrostatic latent image on the surface of the charged image holder; a developing member for containing an electrostatic latent image developer and developing the electrostatic latent image formed on the surface of the image holder into a toner image using the electrostatic latent image developer; a transfer member for transferring the toner image formed on the surface of the image holder to the surface of a recording medium; and a fixing member for fixing the toner image transferred to the surface of the recording medium. As the electrostatic latent image developer, the electrostatic latent image developer according to the present embodiment can be applied.

[0317] In the image forming device involved in the present embodiment, an image forming method (the image forming method involved in the present embodiment) is implemented, which includes the following steps: a charging step for charging the surface of the image retaining body; an electrostatic latent image forming step for forming an electrostatic latent image on the surface of the charged image retaining body; a developing step for developing the electrostatic latent image formed on the surface of the image retaining body into a toner image using the electrostatic latent image developer involved in the present embodiment; a transfer step for transferring the toner image formed on the surface of the image retaining body onto the surface of the recording medium; and a fixing step for fixing the toner image transferred to the surface of the recording medium.

[0318] The image forming device involved in this embodiment applies the following well-known image forming devices: a device of a direct transfer method that directly transfers a toner image formed on the surface of an image retaining body to a recording medium; a device of an intermediate transfer method that transfers a toner image formed on the surface of an image retaining body to the surface of an intermediate transfer body for the first time, and transfers the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium for a second time; a device having a cleaning member that cleans the surface of the image retaining body before charging after transferring the toner image; a device having a destaticizing member that irradiates the surface of the image retaining body with destaticizing light to de-staticize the surface after transferring the toner image and before charging; etc.

[0319] In the case where the image forming device involved in this embodiment is an intermediate transfer type device, the transfer component, for example, applies a structure having the following components: an intermediate transfer body, which transfers the toner image to the surface; a primary transfer component, which transfers the toner image formed on the surface of the image holding body to the surface of the intermediate transfer body; and a secondary transfer component, which transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium for the second time.

[0320] In the image forming apparatus of the present embodiment, for example, the portion including the developing member may be a cartridge structure (processing cartridge) that is detachably mounted on the image forming apparatus. As the processing cartridge, for example, a processing cartridge having a developing member that accommodates the electrostatic latent image developer of the present embodiment is preferably used.

[0321] An example of the image forming apparatus according to the present embodiment is shown below, but the present invention is not limited thereto. In the following description, the main parts shown in the drawings are described, and description of other parts is omitted.

[0322] Figure 1 It is a diagram schematically showing the structure of the image forming apparatus according to the present embodiment.

[0323] Figure 1The image forming apparatus shown in the figure includes first to fourth image forming units 10Y, 10M, 10C, 10K (image forming members) of an electrophotographic method for outputting color images of yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These image forming units (hereinafter, sometimes simply referred to as "units") 10Y, 10M, 10C, 10K are arranged in parallel with each other at a predetermined distance in the horizontal direction. These units 10Y, 10M, 10C, 10K may be process cartridges that are detachable from the image forming apparatus.

[0324] An intermediate transfer belt (an example of an intermediate transfer body) 20 is provided above each unit 10Y, 10M, 10C, and 10K so as to extend through each unit. The intermediate transfer belt 20 is provided so as to be wound around a driving roller 22 and a support roller 24 and to travel in a direction from the first unit 10Y toward the fourth unit 10K. The support roller 24 is urged in a direction away from the driving roller 22 by a spring (not shown) or the like, so that tension is applied to the intermediate transfer belt 20 wound around the two. An intermediate transfer body cleaning device 30 is provided on the image holding surface side of the intermediate transfer belt 20 so as to face the driving roller 22.

[0325] The yellow, magenta, cyan and black toners contained in the toner cartridges 8Y, 8M, 8C and 8K are respectively supplied to the developing devices (an example of developing members) 4Y, 4M, 4C and 4K of the units 10Y, 10M, 10C and 10K.

[0326] The first to fourth units 10Y, 10M, 10C, and 10K have the same structure and operation, and therefore the first unit 10Y disposed on the upstream side in the traveling direction of the intermediate transfer belt and forming a yellow image will be described as a representative.

[0327] The first unit 10Y has a photoreceptor 1Y that functions as an image holder. The following are arranged in order around the photoreceptor 1Y: a charging roller (an example of a charging member) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential; an exposure device (an example of an electrostatic latent image forming member) 3 that forms an electrostatic latent image by exposing the charged surface using a laser beam 3Y based on a color-separated image signal; a developing device (an example of a developing member) 4Y that supplies charged toner to the electrostatic latent image to develop the electrostatic latent image; a primary transfer roller 5Y (an example of a primary transfer member) that transfers the developed toner image to the intermediate transfer belt 20; and a photoreceptor cleaning device (an example of a cleaning member) 6Y that removes the toner remaining on the surface of the photoreceptor 1Y after the primary transfer.

[0328] The primary transfer roller 5Y is arranged inside the intermediate transfer belt 20 and is disposed at a position opposite to the photoreceptor 1Y. A bias power supply (not shown) for applying a primary transfer bias is connected to each of the primary transfer rollers 5Y, 5M, 5C, and 5K of each unit. Each bias power supply changes the value of the transfer bias applied to each primary transfer roller under the control of a control unit (not shown).

[0329] Next, the operation of forming a yellow image in the first unit 10Y will be described.

[0330] First, before the operation is performed, the surface of the photoreceptor 1Y is charged to a potential of -600 V to -800 V by the charging roller 2Y.

[0331] The photoreceptor 1Y has a conductivity (for example, a volume resistivity of 1×10 -6 The photosensitive layer is formed by laminating a photosensitive layer on a substrate with a resistance of 100 Ω·cm or less. Usually, the photosensitive layer has a high resistance (resistance of a general resin), but has a property that the resistivity of the portion irradiated with the laser beam changes when irradiated with a laser beam. Therefore, the laser beam 3Y is irradiated from the exposure device 3 to the surface of the charged photoreceptor 1Y according to the yellow image data sent from the control unit (not shown). As a result, an electrostatic latent image of the yellow image pattern is formed on the surface of the photoreceptor 1Y.

[0332] An electrostatic latent image refers to an image formed on the surface of the photoreceptor 1Y by charging, and is a so-called negative latent image. It is formed as follows: the resistivity of the irradiated portion of the photosensitive layer is reduced by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y flows, while on the other hand, the charge of the portion not irradiated by the laser beam 3Y remains.

[0333] The electrostatic latent image formed on the photoreceptor 1Y rotates to a preset development position as the photoreceptor 1Y travels. Then, at the development position, the electrostatic latent image on the photoreceptor 1Y is developed into a toner image by the developing device 4Y and visualized.

[0334] The developing device 4Y contains, for example, an electrostatic latent image developer containing at least a yellow toner and a carrier. The yellow toner is frictionally charged by being stirred inside the developing device 4Y, and is held on a developer roller (an example of a developer holding member) with a charge of the same polarity (negative polarity) as the charge on the photoreceptor 1Y. Then, by passing the surface of the photoreceptor 1Y through the developing device 4Y, the yellow toner is electrostatically attached to the decharged latent image portion on the surface of the photoreceptor 1Y, thereby developing the latent image with the yellow toner. The photoreceptor 1Y formed with the yellow toner image continues to travel at a preset speed, so that the toner image developed on the photoreceptor 1Y is conveyed to a preset primary transfer position.

[0335] When the yellow toner image on the photoreceptor 1Y is transferred to the primary transfer position, a primary transfer bias is applied to the primary transfer roller 5Y, and an electrostatic force from the photoreceptor 1Y toward the primary transfer roller 5Y acts on the toner image, so that the toner image on the photoreceptor 1Y is transferred to the intermediate transfer belt 20. The transfer bias applied at this time has a (+) polarity opposite to the polarity (-) of the toner, and is controlled by a control unit (not shown) to, for example, +10 μA in the first unit 10Y.

[0336] On the other hand, the toner remaining on the photoreceptor 1Y is removed and recovered by the photoreceptor cleaning device 6Y.

[0337] The primary transfer bias applied to the primary transfer rollers 5M, 5C, and 5K after the second unit 10M is also controlled based on the first unit.

[0338] In this manner, the intermediate transfer belt 20 to which the yellow toner image has been transferred by the first unit 10Y is transported sequentially through the second to fourth units 10M, 10C, and 10K, and transfers are performed multiple times so that the toner images of the respective colors are superimposed.

[0339] After the toner images of four colors have been transferred multiple times by the first to fourth units, the intermediate transfer belt 20 reaches the secondary transfer section composed of the intermediate transfer belt 20, the support roller 24 in contact with the inner surface of the intermediate transfer belt 20, and the secondary transfer roller (an example of the secondary transfer member) 26 arranged on the image holding surface side of the intermediate transfer belt 20. On the other hand, at a preset timing, the recording paper (an example of the recording medium) P is supplied to the gap between the secondary transfer roller 26 and the intermediate transfer belt 20 through the supply mechanism, and the secondary transfer bias is applied to the support roller 24. The transfer bias applied at this time has the same polarity (-) as the polarity (-) of the toner, and the electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, so that the toner image on the intermediate transfer belt 20 is transferred to the recording paper P. The secondary transfer bias at this time is determined based on the resistance detected by the resistance detection member (not shown) that detects the resistance of the secondary transfer section, and is voltage-controlled.

[0340] Then, the recording paper P is conveyed to a pressure-contact portion (nip portion) of a pair of fixing rollers of a fixing device (an example of a fixing member) 28 , and the toner image is fixed to the recording paper P, thereby forming a fixed image.

[0341] Examples of the recording paper P to which the toner image is transferred include plain paper used in electrophotographic copy machines, printers, etc. Examples of the recording medium include, in addition to the recording paper P, OHP films, etc.

[0342] In order to further improve the smoothness of the image surface after fixing, for example, the surface of the recording paper P is preferably smooth, and for example, coated paper obtained by coating the surface of ordinary paper with a resin or the like, coated paper for printing, etc. are preferably used.

[0343] The recording paper P on which the color image has been fixed is conveyed toward the discharge portion, thereby completing a series of color image forming operations.

[0344] <Process Cartridge / Toner Cartridge>

[0345] A process cartridge according to this embodiment will be described.

[0346] The process cartridge according to this embodiment includes a developing member that contains the electrostatic latent image developer according to this embodiment and develops the electrostatic latent image formed on the surface of the image holding member into a toner image using the electrostatic latent image developer, and the process cartridge is attachable to and detachable from the image forming apparatus.

[0347] The processing box involved in this embodiment is not limited to the above-mentioned structure, and can also be a structure having a developing component and at least one component selected from other components set as needed, such as an image retaining body, a charging component, an electrostatic latent image forming component and a transfer component.

[0348] An example of the process cartridge according to the present embodiment is shown below, but the present invention is not limited thereto. In the following description, the main parts shown in the drawings are described, and description of other parts is omitted.

[0349] Figure 2 It is a schematic structural diagram showing a process cartridge according to the present embodiment.

[0350] Figure 2 The processing box 200 shown is constructed, for example, by combining and holding a photosensitive body 107 (an example of an image holding body), a charging roller 108 (an example of a charging component) arranged around the photosensitive body 107, a developing device 111 (an example of a developing component) and a photosensitive body cleaning device 113 (an example of an image holding body cleaning component) into an integral body through a frame 117 provided with a mounting guide 116 and an opening portion 118 for exposure, thereby forming a box.

[0351] Figure 2 109 denotes an exposure device (an example of an electrostatic latent image forming member), 112 denotes a transfer device (an example of a transfer member), 115 denotes a fixing device (an example of a fixing member), and 300 denotes recording paper (an example of a recording medium).

[0352] Next, a toner cartridge according to the present embodiment will be described.

[0353] The toner cartridge according to the present embodiment is a toner cartridge that contains the toner according to the present embodiment and is attached to and detached from an image forming apparatus. The toner cartridge contains replenishing toner for supplying to a developing member provided in the image forming apparatus.

[0354] Figure 1 The image forming apparatus shown is an image forming apparatus having a structure for attaching and detaching toner cartridges 8Y, 8M, 8C, and 8K, and the developing devices 4Y, 4M, 4C, and 4K are connected to the toner cartridges corresponding to the respective developing devices (colors) through toner supply pipes not shown. When the toner contained in the toner cartridge becomes less, the toner cartridge is replaced.

[0355] Example

[0356] Hereinafter, embodiments of the present invention will be described in detail based on examples, but embodiments of the present invention are not limited to these examples.

[0357] In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0358] In the following description, unless otherwise specified, synthesis, production, treatment, measurement, etc. were performed at room temperature (25° C.±3° C.).

[0359] <Production of amorphous polyester resin>

[0360] [Preparation of amorphous polyester resin (A)]

[0361] The following materials were prepared.

[0362] Terephthalic acid: 30 mol parts

[0363] Fumaric acid: 70 mol parts

[0364] Bisphenol A ethylene oxide adduct: 5 mol parts

[0365] Bisphenol A propylene oxide adduct: 95 mol parts

[0366] The above materials were placed in a flask equipped with a stirring device, a nitrogen inlet pipe, a temperature sensor and a distillation tower, and the temperature of the reaction liquid was raised to 220°C over 1 hour, and 1 part of tetraethoxytitanium was added to 100 parts of the above materials. The temperature of the reaction liquid was raised to 230°C over 30 minutes while distilling off the generated water, and the dehydration condensation reaction was continued for 1 hour while the temperature of the reaction liquid was maintained at 230°C. Then, the temperature of the reactant was cooled to room temperature. In this way, an amorphous polyester resin (A) with an acid value of 15.0 mgKOH / g, a weight average molecular weight of 18,000, and a glass transition temperature of 60°C was obtained.

[0367] [Preparation of amorphous polyester resin (B)]

[0368] The following materials were prepared.

[0369] Terephthalic acid: 25 mol parts

[0370] Fumaric acid: 75 mol parts

[0371] Bisphenol A ethylene oxide adduct: 5 mol parts

[0372] Bisphenol A propylene oxide adduct: 95 mol parts

[0373] The above materials were placed in a flask equipped with a stirring device, a nitrogen inlet pipe, a temperature sensor and a distillation tower, and the temperature of the reaction liquid was raised to 220°C over 1 hour, and 1 part of tetraethoxytitanium was added to 100 parts of the above materials. The temperature of the reaction liquid was raised to 230°C over 30 minutes while distilling off the generated water, and the dehydration condensation reaction was continued for 1 hour while the temperature of the reaction liquid was maintained at 230°C. Then, the temperature of the reactant was cooled to room temperature. In this way, an amorphous polyester resin (B) with an acid value of 0.5 mgKOH / g, a weight average molecular weight of 18,000, and a glass transition temperature of 60°C was obtained.

[0374] [Preparation of amorphous polyester resin (C)]

[0375] The following materials were prepared.

[0376] Terephthalic acid: 27 mol parts

[0377] Fumaric acid: 73 mol parts

[0378] Bisphenol A ethylene oxide adduct: 5 mol parts

[0379] Bisphenol A propylene oxide adduct: 95 mol parts

[0380] The above materials were placed in a flask equipped with a stirring device, a nitrogen inlet pipe, a temperature sensor and a distillation tower, and the temperature of the reaction liquid was raised to 220°C over 1 hour, and 1 part of tetraethoxytitanium was added to 100 parts of the above materials. The temperature of the reaction liquid was raised to 230°C over 30 minutes while distilling off the generated water, and the dehydration condensation reaction was continued for 1 hour while the temperature of the reaction liquid was maintained at 230°C. Then, the temperature of the reactant was cooled to room temperature. In this way, an amorphous polyester resin (C) with an acid value of 1.0 mgKOH / g, a weight average molecular weight of 18,000, and a glass transition temperature of 60°C was obtained.

[0381] [Preparation of amorphous polyester resin (D)]

[0382] The following materials were prepared.

[0383] Terephthalic acid: 37.5 mol parts

[0384] Fumaric acid: 62.5 mol parts

[0385] Bisphenol A ethylene oxide adduct: 5 mol parts

[0386] Bisphenol A propylene oxide adduct: 95 mol parts

[0387] The above materials were placed in a flask equipped with a stirring device, a nitrogen inlet pipe, a temperature sensor and a distillation tower, and the temperature of the reaction solution was raised to 220°C over 1 hour, and 1 part of tetraethoxytitanium was added to 100 parts of the above materials. The temperature of the reaction solution was raised to 230°C over 30 minutes while distilling off the generated water, and the dehydration condensation reaction was continued for 1 hour while the temperature of the reaction solution was maintained at 230°C. Then, the temperature of the reactant was cooled to room temperature. In this way, an amorphous polyester resin (D) having an acid value of 50.0 mgKOH / g, a weight average molecular weight of 18,000, and a glass transition temperature of 60°C was obtained.

[0388] [Preparation of amorphous polyester resin (E)]

[0389] The following materials were prepared.

[0390] Terephthalic acid: 42 parts by mole

[0391] Fumaric acid: 58 mol parts

[0392] Bisphenol A ethylene oxide adduct: 5 mol parts

[0393] Bisphenol A propylene oxide adduct: 95 mol parts

[0394] The above materials were placed in a flask equipped with a stirring device, a nitrogen inlet pipe, a temperature sensor and a distillation tower, and the temperature of the reaction solution was raised to 220°C over 1 hour, and 1 part of tetraethoxytitanium was added to 100 parts of the above materials. The temperature of the reaction solution was raised to 230°C over 30 minutes while distilling off the generated water, and the dehydration condensation reaction was continued for 1 hour while the temperature of the reaction solution was maintained at 230°C. Then, the temperature of the reactant was cooled to room temperature. In this way, an amorphous polyester resin (E) with an acid value of 70.0 mgKOH / g, a weight average molecular weight of 18,000, and a glass transition temperature of 60°C was obtained.

[0395] <Preparation of Pigment-Containing Polyester Resin Particle Dispersion>

[0396] [Preparation of Pigment-Containing Polyester Resin Particle Dispersion (P1)]

[0397] The following materials were prepared.

[0398] Amorphous polyester resin (A): 160 parts

[0399] Carbon black (trade name: Regal 330, Cabot Corporation): 40 parts

[0400] Alkaline compound: 50% sodium hydroxide aqueous solution: 0.2 parts

[0401] Surfactant: 48.5% sodium dodecyl diphenyl ether disulfonate aqueous solution (trade name: ELEMINOL MON-7, SANYO CHEMICAL INDUSTRIES, LTD.): 4.1 parts

[0402] Deionized water (1): 150 parts of deionized water at 90°C

[0403] Deionized water (2): 150 parts of deionized water at 90°C

[0404] Deionized water (3): 150 parts of deionized water at 90°C

[0405] A twin-screw kneading extruder (model: TEM26SS, Toshiba Machine Co., Ltd.) was prepared. The barrel of the twin-screw kneading extruder used in this example was formed by connecting a plurality of barrel blocks.

[0406] -Mixing process-

[0407] The barrel temperature of the twin-screw compounding extruder was set to 95°C, and the screw speed was set to 400 rpm. The amorphous polyester resin (A) and carbon black were added to the raw material inlet of the twin-screw compounding extruder, mixed and stirred, and the treated material was temporarily discharged. The treated material and 50% sodium hydroxide aqueous solution were added to the raw material inlet of the twin-screw compounding extruder, and a surfactant was added from the barrel of the fourth block, and all were mixed and stirred to form a mixture containing polyester resin, pigment, alkaline compound and surfactant.

[0408] -Emulsification process-

[0409] Furthermore, while the twin-screw kneading extruder was operated so that the average supply amount of the mixture became 12 kg / h, deionized water (1) was added from the barrel of the fifth block, deionized water (2) was added from the barrel of the seventh block, and deionized water (3) was added from the barrel of the ninth block to emulsify the mixture, thereby obtaining a pigment-containing polyester resin particle dispersion (P1). The solid content concentration of the pigment-containing polyester resin particle dispersion (P1) was 25%.

[0410] The particle size distribution of the particles in the pigment-containing polyester resin particle dispersion (P1) was measured using a laser diffraction particle size distribution analyzer (model: LS13-320, Beckman Coulter, Inc.) The volume average particle size of the particles in the pigment-containing polyester resin particle dispersion (P1) was 200 nm.

[0411] [Preparation of Pigment-Containing Polyester Resin Particle Dispersions (P2) to (P10), (P12) to (P16)]

[0412] The same method as the preparation of the pigment-containing polyester resin particle dispersion (P1) was used, but the operating conditions of the twin-screw kneading extruder or the type of amorphous polyester resin were changed as shown in Table 1, and the amount of carbon black used was adjusted as needed to prepare the pigment-containing polyester resin particle dispersion.

[0413] [Preparation of Pigment-Containing Polyester Resin Particle Dispersion (P11)]

[0414] The following materials were prepared.

[0415] Organic solvent (1): ethyl acetate: 40 parts

[0416] Organic solvent (2): 2-butanol: 25 parts

[0417] Amorphous polyester resin (A): 160 parts

[0418] Carbon black (trade name: Regal 330, Cabot Corporation): 40 parts

[0419] ·Alkaline compound: 10% ammonia water: 3 times the molar equivalent to the acid value of the polyester resin

[0420] Deionized water (4): 400 parts of deionized water at 40°C

[0421] Surfactant: 48.5% sodium dodecyl diphenyl ether disulfonate aqueous solution (trade name: ELEMINOLMON-7, SANYO CHEMICAL INDUSTRIES, LTD.): 1.0 part

[0422] -Dissolution process-

[0423] An organic solvent (1) and an organic solvent (2) are added to a stirring tank equipped with a stirrer, a capacitor, a heating device and a thermometer to prepare a mixed solvent. While the temperature in the stirring tank is maintained at 40° C. and stirred, an amorphous polyester resin (A) is added and dissolved, and carbon black is gradually added and dispersed.

[0424] -Emulsification process-

[0425] While maintaining the temperature in the stirring tank and stirring continuously, the alkaline compound was added and stirred for 30 minutes. The inside of the stirring tank was replaced with dry nitrogen, and while stirring while maintaining the temperature at 40°C, deionized water (4) was added dropwise at a rate of 2 parts / minute to emulsify the contents. After the addition was completed, the heating of the stirring tank was stopped, and after the temperature of the emulsion was lowered to room temperature, the emulsion was bubbled with dry nitrogen for 48 hours to remove the organic solvent from the emulsion. Next, a surfactant was added, and deionized water was added to adjust the solid content concentration to 25%, to obtain a pigment-containing polyester resin particle dispersion (P11). The volume average particle size of the particles in the pigment-containing polyester resin particle dispersion (P11) was 200nm.

[0426] <Preparation of Pigment-Containing Styrene Acrylic Resin Particle Dispersion Liquid (SA1)>

[0427] The following materials were prepared.

[0428] Deionized water: 300 parts

[0429] Sodium dodecylbenzene sulfonate: 3 parts

[0430] Styrene: 60 parts

[0431] ·2-Ethylhexyl methacrylate: 15 parts

[0432] Ethylene glycol dimethacrylate: 5 parts

[0433] Polymerization initiator: tert-butyl peroxy-2-ethylhexanoate: 1 part

[0434] Deionized water and sodium dodecylbenzenesulfonate were added to a stirring tank and stirred and mixed. The above-mentioned monomers and a polymerization initiator were added thereto and stirred and mixed to obtain a monomer solution.

[0435] The following materials were prepared.

[0436] Deionized water: 180 parts

[0437] Sodium dodecylbenzene sulfonate: 1.8 parts

[0438] Carbon black (trade name: Regal 330, Cabot Corporation): 20 parts

[0439] Deionized water and sodium dodecylbenzenesulfonate were added to a bead mill and mixed, and then carbon black was added and dispersed to obtain a pigment dispersion.

[0440] The monomer solution and the pigment dispersion were placed in a stirring tank, stirred at 30°C for 20 minutes, and then the temperature was raised to 90°C and maintained for 3 hours while stirring. Then, the liquid temperature was cooled to room temperature, the solid content was filtered out, and it was thoroughly washed with deionized water. The washed solid matter was dispersed in deionized water to which a surfactant (sodium dodecyl diphenyl ether disulfonate) was added to obtain a pigment-containing styrene acrylic resin particle dispersion (SA1) with a solid content concentration of 25%. The volume average particle size of the particles in the pigment-containing styrene acrylic resin particle dispersion (SA1) was 200 nm.

[0441] <Preparation of amorphous polyester resin particle dispersion (1)>

[0442] The following materials were prepared.

[0443] Terephthalic acid: 30 mol parts

[0444] Fumaric acid: 70 mol parts

[0445] Bisphenol A ethylene oxide adduct: 5 mol parts

[0446] Bisphenol A propylene oxide adduct: 95 mol parts

[0447] The above materials were placed in a flask equipped with a stirring device, a nitrogen inlet pipe, a temperature sensor and a distillation tower, and the temperature of the reaction liquid was raised to 220°C over 1 hour, and 1 part of tetraethoxytitanium was added to 100 parts of the above materials. The temperature of the reaction liquid was raised to 230°C over 30 minutes while distilling off the generated water, and the dehydration condensation reaction was continued for 1 hour while the temperature of the reaction liquid was maintained at 230°C. Then, the temperature of the reactant was cooled to room temperature. In this way, an amorphous polyester resin with a weight average molecular weight of 18,000 and a glass transition temperature of 60°C was obtained.

[0448] A mixed solvent was prepared by adding 40 parts of ethyl acetate and 25 parts of 2-butanol to a container equipped with a temperature regulating member and a nitrogen replacement member. 100 parts of amorphous polyester resin was gradually added to the mixed solvent to dissolve it, and a 10% aqueous ammonia solution (equivalent to 3 times the amount in molar ratio relative to the acid value of the resin) was added and stirred for 30 minutes. Next, the inside of the container was replaced with dry nitrogen, the temperature of the reaction liquid was maintained at 40°C, and while stirring the reaction liquid, 400 parts of deionized water was added dropwise at a rate of 2 parts / minute to emulsify it. After the addition of deionized water was completed, the temperature of the emulsion was cooled to room temperature, and while stirring the emulsion, dry nitrogen was bubbled for 48 hours to reduce the total amount of ethyl acetate and 2-butanol to less than 1000 ppm. Deionized water was added to the emulsion to adjust the solid content concentration to 20%. In this way, an amorphous polyester resin particle dispersion (1) was obtained. The volume average particle size of the particles in the amorphous polyester resin particle dispersion (1) was 180 nm.

[0449] <Preparation of Release Agent Particle Dispersion (1)>

[0450] The following materials were prepared.

[0451] Paraffin (HNP-9, NIPPON SEIRO CO., LTD.): 100 parts

[0452] Deionized water: 350 parts

[0453] Anionic surfactant (trade name: NEOGEN RK, manufactured by DKS Co. Ltd., 20% aqueous solution): 1 part

[0454] The above materials were mixed and heated to 100°C, dispersed using a homogenizer (ULTRA TURRAX T50, IKA), and then dispersed using a pressure-dispensing homogenizer (Manton-Gaulin high-pressure homogenizer, Gaulin). When the volume average particle size reached 200 nm, the particles were recovered to obtain a release agent particle dispersion (1) having a solid content concentration of 20%.

[0455] <Example 1>

[0456] [Manufacturing of Toner Particles]

[0457] The following materials were prepared.

[0458] Deionized water: 200 parts

[0459] Amorphous polyester resin particle dispersion (1): 80 parts

[0460] Pigment-containing polyester resin particle dispersion (P1): 3.7 parts

[0461] Release agent particle dispersion (1): 8.0 parts

[0462] Anionic surfactant (trade name: NEOGEN RK, manufactured by DKS Co. Ltd., 20% aqueous solution): 1.1 parts

[0463] -First Coagulation Step-

[0464] The above materials were placed in a round stainless steel flask, 0.1N nitric acid was added and the pH was adjusted to 3.5, and 30 parts of a nitric acid aqueous solution with a polyaluminum chloride concentration of 10% was added. The liquid temperature was adjusted to 30°C using an oil bath, and a homogenizer (trade name: ULTRA TURRAX T50, IKA) was used for dispersion treatment, and then the liquid temperature was raised to 45°C and maintained for 30 minutes to form first aggregated particles.

[0465] -Second Coagulation Step-

[0466] While the liquid temperature of the dispersion containing the first aggregated particles was maintained at 45° C., 20 parts of the amorphous polyester resin particle dispersion (1) was added and maintained for 60 minutes to form second aggregated particles.

[0467] -Combination process-

[0468] A 0.1 N sodium hydroxide aqueous solution was added to the dispersion containing the second aggregated particles and the pH was adjusted to 8.5. The liquid temperature was raised to 84°C and maintained for 150 minutes. Then, the dispersion was cooled to 20°C at a rate of 20°C / min, and the solid content was filtered out, washed with deionized water, and dried. The dried product was sieved to obtain toner particles (1). The volume average particle size of the toner particles (1) was 6.0 μm.

[0469] [Manufacturing of external toner]

[0470] 1.5 parts of hydrophobic silica particles (product code: RY50, NIPPONAEROSIL CO., LTD.) and 1.0 part of hydrophobic titanium oxide (product code: T805, NIPPON AEROSIL CO., LTD.) were added to 100 parts of the toner particles (1), and mixed at 10000 rpm for 30 seconds using a sample mill. Then, the mixture was sieved with a vibration sieve having an aperture of 45 μm to obtain an external toner.

[0471] [Manufacturing of developer]

[0472] 8 parts of the external toner and 92 parts of the following carrier (1) were placed in a V mixer and stirred for 20 minutes, and then sieved with a sieve having an aperture of 212 μm to obtain a developer.

[0473] -Manufacturing of carrier (1)-

[0474] 14 parts of toluene, 5 parts of polymethyl methacrylate (weight average molecular weight: 75000) and 0.2 parts of carbon black (product code: VXC-72, Cabot Corporation) were placed in a sand mill and dispersed to prepare a dispersion. The dispersion and 100 parts of ferrite particles (average particle size: 35 μm) were placed in a vacuum degassing kneader and dried under reduced pressure while stirring to obtain a carrier (1).

[0475] <Example 2 to Example 15, Comparative Example 1 to Comparative Example 2>

[0476] The same procedure as in Example 1 was carried out except that the type of the pigment-containing resin particle dispersion was changed as shown in Table 1, and toner particles, an external toner, and a developer were prepared.

[0477] <Performance Evaluation>

[0478] [Proportion of coarse particles]

[0479] Using a standard sieve with an aperture of 20 μm, pigmented polyester resin particle dispersions (P1) to (P16) and pigmented styrene acrylic resin particle dispersions (SA1) equivalent to 100 g of solid content were sieved. The mass ratio of the solid content that did not pass through the sieve was classified as follows. G1 to G3 were within the allowable range.

[0480] G1: less than 0.5%

[0481] G1.5: 0.5% or more and less than 1%

[0482] G2: 1% or more and less than 1.5%

[0483] G2.5: 1.5% or more and less than 2%

[0484] G3: 2% or more and less than 5%

[0485] G4: 5% or more

[0486] [Low temperature fixability]

[0487] The following operations and image formation were performed in an environment of a temperature of 28° C. and a relative humidity of 85%.

[0488] As recording paper, Premier TCF (basic weight 80 g / m 2, A4 size, FUJIFILM Business Innovation Corp.). Premier TCF is a paper with a relatively rough surface, and it is difficult to uniformly transfer heat to the toner on the paper, and low-temperature fixing of the toner is relatively difficult.

[0489] The developer was filled in the developer unit of a modified image forming apparatus Apeos Port-V C7775 (FUJIFILM Business Innovation Corp.). The temperature of the fixing machine was set to 140°C, and the amount of toner on the paper was set to 1.0 mg / cm 2 .

[0490] A black solid image with an image density of 100% and a black halftone image with an image density of 30% were formed at the front and rear ends of the paper, respectively. 1,000 sheets were output, and the 1,000 black solid images and black halftone images were observed with the naked eye, and the presence or absence of white spots were classified as follows. A to C are within the allowable range.

[0491] A: No white spots were found.

[0492] B: Very few white spots were observed.

[0493] C: A small amount of white spots were confirmed.

[0494] D: White spots are observed to an unacceptable degree.

[0495] [Uneven Image]

[0496] The developer was filled in the developer unit of a modified image forming apparatus Apeos Port-V C7775 (FUJIFILM Business Innovation Corp.), and the temperature and humidity inside the image forming apparatus were adjusted to 30° C. and a relative humidity of 90%, and the apparatus was left for 3 days.

[0497] After 3 days of storage, 20,000 sheets were immediately printed on A3 size plain paper Figure 3 A black image (area coverage is 50%, image portion is 100% density) is printed on A3 size plain paper. Figure 3 (B) is a black image (area coverage is 50%, image portion has a density of 100%).

[0498] The concentration was measured at 10 locations using a concentration meter (trade name: X-Rite938, X-rite Corporation). Figure 3 The density of the black image of (B) was calculated. The difference between the maximum value and the minimum value of the image density at 10 locations was calculated and classified as follows. A to B are within the allowable range.

[0499] A: Image density difference is 0.20 or less

[0500] B: Image density difference is more than 0.20 and less than 0.30

[0501] C: Image density difference is more than 0.30 and less than 0.35

[0502] D: Image density difference exceeds 0.35

[0503]

[0504] The pigment-containing polyester resin particles, the method for producing the pigment-containing polyester resin particles, the method for producing a toner for electrostatic latent image development, the toner for electrostatic latent image development, the electrostatic latent image developer, the toner cartridge, the process cartridge, the image forming apparatus and the image forming method of the present invention include the following aspects. (1)

[0506] A pigment-containing polyester resin particle, comprising a polyester resin and a pigment, wherein the pigment-containing polyester resin particle comprises:

[0507] The pigment is not exposed on the surface of the pigment-containing polyester resin particle and is not inscribed in the outline of the pigment-containing polyester resin particle. (2)

[0509] The pigment-containing polyester resin particles according to (1), wherein

[0510] The volume average particle size is 50 nm or more and 500 nm or less. (3)

[0512] The pigment-containing polyester resin particles according to (1) or (2), wherein

[0513] The content of the pigment is 10% by mass or more and 60% by mass or less. (4)

[0515] The pigment-containing polyester resin particles according to any one of (1) to (3), wherein

[0516] The average diameter of the pigment is 10 nm or more and 400 nm or less. (5)

[0518] The pigment-containing polyester resin particles according to any one of (1) to (4), wherein

[0519] The acid value of the polyester resin is 1 mgKOH / g or more and 50 mgKOH / g or less. (6)

[0521] A method for producing pigment-containing polyester resin particles, which produces the pigment-containing polyester resin particles described in any one of (1) to (5), wherein the method for producing pigment-containing polyester resin particles comprises the following steps:

[0522] applying heat and shear force to the polyester resin, the pigment, the alkaline compound, and the surfactant and mixing them to obtain a mixture in which the pigment is dispersed in the molten polyester resin; and

[0523] An aqueous medium is added to the mixture while applying a shear force to emulsify the mixture. (7)

[0525] A method for producing pigment-containing polyester resin particles, which produces the pigment-containing polyester resin particles described in any one of (1) to (5), wherein the method for producing pigment-containing polyester resin particles comprises the following steps:

[0526] Applying heat and shear force to the polyester resin, the pigment and the organic solvent and mixing them to obtain a mixture in which the pigment is dispersed in the dissolved polyester resin; and

[0527] After adding the basic compound to the mixture, an aqueous medium is added while applying a shear force to emulsify the mixture. (8)

[0529] A method for producing a toner for electrostatic latent image development comprises the following steps:

[0530] In a dispersion liquid containing the pigment-containing polyester resin particles according to any one of (1) to (5), the pigment-containing polyester resin particles are agglomerated to form aggregated particles; and

[0531] The dispersion liquid containing the aggregated particles is heated to fuse the aggregated particles into a body, thereby forming toner particles. (9)

[0533] A toner for developing an electrostatic latent image, comprising toner particles containing a polyester resin and a pigment,

[0534] In the toner particles, the number ratio of the pigment having a maximum Feret diameter of 250 nm or more is 20% by number or less. (10)

[0536] An electrostatic latent image developer comprising the electrostatic latent image developing toner described in (9). (11)

[0538] A toner cartridge containing the electrostatic latent image developing toner described in (9), and

[0539] Mounted on and removed from the image forming apparatus. (12)

[0541] A process cartridge comprising a developing member, wherein the developing member contains the electrostatic latent image developer described in (10) and develops the electrostatic latent image formed on the surface of an image holding member into a toner image using the electrostatic latent image developer.

[0542] The process cartridge is attachable to and detachable from the image forming apparatus. (13)

[0544] An image forming device comprising:

[0545] Image holding body;

[0546] a charging member for charging the surface of the image holding member;

[0547] An electrostatic latent image forming member for forming an electrostatic latent image on the charged surface of the image holding member;

[0548] a developing member that contains the electrostatic latent image developer described in (10) and develops the electrostatic latent image formed on the surface of the image holding member into a toner image using the electrostatic latent image developer;

[0549] a transfer member that transfers the toner image formed on the surface of the image holding member to the surface of a recording medium; and

[0550] The fixing member fixes the toner image transferred to the surface of the recording medium. (14)

[0552] An image forming method, comprising:

[0553] A charging process to charge the surface of the image holding body;

[0554] An electrostatic latent image forming step of forming an electrostatic latent image on the charged surface of the image holding member;

[0555] a developing step of developing the electrostatic latent image formed on the surface of the image holding member into a toner image using the electrostatic latent image developer described in (10);

[0556] a transfer step of transferring the toner image formed on the surface of the image holding member to the surface of a recording medium; and

[0557] In the fixing step, the toner image transferred to the surface of the recording medium is fixed.

[0558] According to (1), there is provided a pigmented polyester resin particle having fewer coarse particles than a pigmented polyester resin particle in which the pigment is exposed on the surface of the pigmented polyester resin particle or inscribed in the outline of the pigmented polyester resin particle.

[0559] According to (2), there is provided a pigment-containing polyester resin particle having a smaller number of coarse particles than a pigment-containing polyester resin particle having a volume average particle size of less than 50 nm or exceeding 500 nm.

[0560] According to (3), there is provided a pigment-containing polyester resin particle having a smaller amount of coarse particles than a pigment-containing polyester resin particle having a pigment content of less than 10% by mass or more than 60% by mass.

[0561] According to (4), there is provided a pigment-containing polyester resin particle having fewer coarse particles than a pigment-containing polyester resin particle having an average diameter of the pigment of less than 10 nm or exceeding 400 nm.

[0562] According to (5), there is provided a pigment-containing polyester resin particle having fewer coarse particles than a pigment-containing polyester resin particle having an acid value of the polyester resin of less than 1 mgKOH / g or more than 50 mgKOH / g.

[0563] According to (6), a method for producing pigment-containing polyester resin particles having a small amount of coarse particles is provided.

[0564] According to (7), a method for producing pigment-containing polyester resin particles having a small amount of coarse particles is provided.

[0565] According to (8), a method for producing a toner for developing an electrostatic latent image which is excellent in low-temperature fixing property and hardly causes image unevenness is provided.

[0566] According to (9), a toner for developing an electrostatic latent image which is excellent in low-temperature fixing property and hardly causes image unevenness is provided.

[0567] According to (10), an electrostatic latent image developer having excellent low-temperature fixing properties and being less likely to cause image unevenness is provided.

[0568] According to (11), there is provided a toner cartridge containing an electrostatic latent image developing toner which is excellent in low-temperature fixing property and hardly causes image unevenness.

[0569] According to (12), there is provided a process cartridge containing an electrostatic latent image developer which is excellent in low-temperature fixing property and is less likely to cause image unevenness.

[0570] According to (13), an image forming apparatus is provided which has excellent low-temperature fixing properties and is less likely to cause image unevenness.

[0571] According to (14), there is provided an image forming method which is excellent in low-temperature fixing property and is less likely to cause image unevenness.

[0572] The above-mentioned embodiments of the present invention are provided for the purpose of illustration and description. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed methods. Obviously, various modifications and changes are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily understand the principles of the present invention and its application. Thus, other technicians in the art can understand the present invention through various variations optimized for specific uses assumed to be various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

Claims

1. A pigment-containing polyester resin particle, comprising a polyester resin and a pigment, wherein the pigment-containing polyester resin particle comprises: The pigment is not exposed on the surface of the pigment-containing polyester resin particle and is not inscribed in the outline of the pigment-containing polyester resin particle.

2. The pigment-containing polyester resin particles according to claim 1, wherein The volume average particle size is 50 nm or more and 500 nm or less.

3. The pigment-containing polyester resin particles according to claim 1 or 2, wherein The content of the pigment is 10% by mass or more and 60% by mass or less.

4. The pigment-containing polyester resin particles according to any one of claims 1 to 3, wherein The average diameter of the pigment is 10 nm or more and 400 nm or less.

5. The pigment-containing polyester resin particles according to any one of claims 1 to 4, wherein The acid value of the polyester resin is 1 mgKOH / g or more and 50 mgKOH / g or less.

6. A method for producing pigment-containing polyester resin particles, comprising producing the pigment-containing polyester resin particles according to any one of claims 1 to 5, the method comprising the following steps: applying heat and shear force to the polyester resin, the pigment, the alkaline compound, and the surfactant and mixing them to obtain a mixture in which the pigment is dispersed in the molten polyester resin; and An aqueous medium is added to the mixture while applying a shear force to emulsify the mixture.

7. A method for producing pigment-containing polyester resin particles, comprising producing the pigment-containing polyester resin particles according to any one of claims 1 to 5, the method comprising the following steps: Applying heat and shear force to the polyester resin, the pigment and the organic solvent and mixing them to obtain a mixture in which the pigment is dispersed in the dissolved polyester resin; and After adding the basic compound to the mixture, an aqueous medium is added while applying a shear force to emulsify the mixture.

8. A method for producing a toner for developing an electrostatic latent image, comprising the following steps: In a dispersion liquid containing the pigment-containing polyester resin particles according to any one of claims 1 to 5, the pigment-containing polyester resin particles are agglomerated to form aggregated particles; and The dispersion liquid containing the aggregated particles is heated to fuse the aggregated particles into a body, thereby forming toner particles.

9. A toner for developing an electrostatic latent image, comprising toner particles containing a polyester resin and a pigment, In the toner particles, the number ratio of the pigment having a maximum Feret diameter of 250 nm or more is 20% by number or less. 10 . An electrostatic latent image developer comprising the electrostatic latent image developing toner according to claim 9 .

11. A toner cartridge containing the electrostatic latent image developing toner according to claim 9, and Mounted on and removed from the image forming apparatus.

12. A process cartridge comprising a developing member, the developing member containing the electrostatic latent image developer according to claim 10, and developing the electrostatic latent image formed on the surface of an image holding member into a toner image using the electrostatic latent image developer, The process cartridge is attachable to and detachable from the image forming apparatus.

13. An image forming apparatus comprising: Image holding body; a charging member for charging the surface of the image holding member; An electrostatic latent image forming member for forming an electrostatic latent image on the charged surface of the image holding member; a developing member that contains the electrostatic latent image developer according to claim 10 and develops the electrostatic latent image formed on the surface of the image holding member into a toner image using the electrostatic latent image developer; a transfer member for transferring the toner image formed on the surface of the image holding body to the surface of a recording medium; and The fixing member fixes the toner image transferred to the surface of the recording medium.

14. An image forming method, comprising: A charging process to charge the surface of the image holding body; An electrostatic latent image forming step of forming an electrostatic latent image on the charged surface of the image holding member; a developing step of developing the electrostatic latent image formed on the surface of the image holding member into a toner image using the electrostatic latent image developer according to claim 10; a transfer step of transferring the toner image formed on the surface of the image holding body to the surface of a recording medium; and In the fixing step, the toner image transferred to the surface of the recording medium is fixed.

Images