Toner for electrostatic image development, electrostatic image developer, toner cartridge, process cartridge, image forming apparatus and method

Abstract

The present invention relates to a toner for electrostatic image development, an electrostatic image developer, a toner cartridge, a processing cartridge, an image forming apparatus and a method. The toner for electrostatic image development comprises toner particles and layered structure compound particles, wherein the layered structure compound particles have a crystallite diameter calculated from the maximum peak width of a CuKα-ray X-ray diffraction pattern of not less than 1.5 μm and a number average particle diameter Dn of not less than 0.3 μm and not more than 2.0 μm, and a ratio Dn / Dv of the number average particle diameter Dn of the layered structure compound particles to the volume average particle diameter Dv of the toner particles of not less than 0.03 and not more than 0.7.

Description

Technical Field

[0001] The present invention relates to a toner for developing an electrostatic image, an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus, and an image forming method. Background Art

[0002] Japanese Patent Application Laid-Open No. 2006-317489 discloses a toner prepared by adding 0.1 to 2.0 parts by weight of melamine cyanurate powder having a volume average particle size of 3 to 9 μm to a base toner having an average circularity of 0.94 to 0.995 and a volume average particle size of 3 to 9 μm, based on 100 parts by weight of the base toner.

[0003] Japanese Patent Application Laid-Open No. 2009-237274 discloses a positively chargeable toner, wherein 0.01 to 0.5 parts by weight of melamine cyanurate particles having a number average primary particle size of 0.05 μm to 1.5 μm are added to colored resin particles containing a binder resin, a colorant, and a positive charge control agent, relative to 100 parts by weight of the colored resin particles. Summary of the invention

[0004] Technical problem to be solved by the invention

[0005] The technical problem to be solved by the present invention is to provide a toner for electrostatic image development, comprising toner particles and layered structure compound particles, wherein the crystallite diameter of the layered structure compound particles is less than or greater than Or compared with the electrostatic image developing toner in which the number average particle size Dn of the layered structure compound particles is less than 0.3μm or greater than 2.0μm, or the ratio Dn / Dv of the number average particle size Dn of the layered structure compound particles to the volume average particle size Dv of the toner particles is less than 0.03 or greater than 0.7, the electrostatic image developing toner provided by the present invention can suppress the generation of color stripes caused by leakage of the toner or external additive from the cleaning scraper of the intermediate transfer body.

[0006] According to a first aspect of the present invention, there is provided a toner for developing an electrostatic image, wherein:

[0007] The toner includes toner particles and layered structure compound particles.

[0008] The crystallite diameter of the above-mentioned layered structure compound particles calculated from the maximum peak width of the CuKα-ray X-ray diffraction pattern is above and the number average particle size Dn of the layered structure compound particles is 0.3 μm or more and 2.0 μm or less,

[0009] The ratio Dn / Dv of the number average particle diameter Dn of the layered structure compound particles to the volume average particle diameter Dv of the toner particles is 0.03 or more and 0.7 or less.

[0010] According to the second aspect of the present invention, the content of the layered structure compound particles is 0.1% by mass or more and 2.0% by mass or less based on the entire electrostatic image developing toner.

[0011] According to a third aspect of the present invention, the content of the layered structure compound particles is 0.1% by mass or more and 1.0% by mass or less based on the entire electrostatic image developing toner.

[0012] According to the fourth aspect of the present invention, the crystallite diameter of the layered compound particles is above the following.

[0013] According to a fifth aspect of the present invention, the layered structure compound particles have a number average particle size Dn of 0.3 μm or more and 1.8 μm or less.

[0014] According to a sixth aspect of the present invention, a ratio Dn / Dv of a number average particle diameter Dn of the layered structure compound particles to a volume average particle diameter Dv of the toner particles is not less than 0.05 and not more than 0.6.

[0015] According to a seventh aspect of the present invention, the toner particles have a volume average particle diameter Dv of 3.0 μm or more and 10.0 μm or less.

[0016] According to an eighth aspect of the present invention, the toner particles have a volume average particle diameter Dv of 3.5 μm or more and 7.0 μm or less.

[0017] According to a ninth aspect of the present invention, the layered structure compound particles include at least one selected from the group consisting of free melamine cyanurate particles, boron nitride particles, graphite fluoride particles, molybdenum disulfide particles, and mica particles.

[0018] According to a tenth aspect of the present invention, there is provided an electrostatic image developer comprising the above-mentioned electrostatic image developing toner.

[0019] According to an eleventh aspect of the present invention, there is provided a toner cartridge that is detachably mounted in an image forming apparatus and stores the above-mentioned toner for developing an electrostatic image.

[0020] According to a twelfth aspect of the present invention, there is provided a process cartridge that is detachably mounted in an image forming apparatus, the process cartridge comprising:

[0021] a developing mechanism storing the electrostatic image developer and developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer;

[0022] an intermediate transfer body to which the toner image formed on the surface of the image holding body is transferred; and

[0023] The cleaning mechanism includes a scraper in contact with the surface of the intermediate transfer body, and uses the scraper to clean the toner remaining on the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium.

[0024] According to a thirteenth aspect of the present invention, there is provided an image forming apparatus comprising:

[0025] Image holding body;

[0026] A charging mechanism for charging the surface of the image holding body;

[0027] An electrostatic image forming mechanism for forming an electrostatic image on the charged surface of the image holding member;

[0028] a developing mechanism storing the electrostatic image developer and developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer;

[0029] an intermediate transfer body to which the toner image formed on the surface of the image holding body is transferred;

[0030] A primary transfer mechanism, transferring the toner image formed on the surface of the image holding body to the surface of the intermediate transfer body;

[0031] A secondary transfer mechanism transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium;

[0032] a fixing mechanism for fixing the toner image transferred to the surface of the recording medium; and

[0033] The cleaning mechanism includes a scraper in contact with the surface of the intermediate transfer body, and uses the scraper to clean the toner remaining on the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium.

[0034] According to a 14th aspect of the present invention, there is provided an image forming method comprising the following steps:

[0035] A charging step of charging the surface of the image holding body;

[0036] An electrostatic image forming step of forming an electrostatic image on the charged surface of the image holding member;

[0037] a developing step of developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer;

[0038] a primary transfer step of transferring the toner image formed on the surface of the image holding body to the surface of the intermediate transfer body;

[0039] A secondary transfer step of transferring the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium;

[0040] a fixing step of fixing the toner image transferred to the surface of the recording medium; and

[0041] In the cleaning step, the scraper is brought into contact with the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium, so as to clean the toner remaining on the surface of the intermediate transfer body.

[0042] Effects of the Invention

[0043] According to the first, seventh, eighth or ninth aspect, there is provided a toner for electrostatic image development, comprising toner particles and layered structure compound particles, wherein the layered structure compound particles have a crystallite diameter of less than or greater than Or compared with the electrostatic image developing toner in which the number average particle size Dn of the layered structure compound particles is less than 0.3μm or greater than 2.0μm, or the ratio Dn / Dv of the number average particle size Dn of the layered structure compound particles to the volume average particle size Dv of the toner particles is less than 0.03 or greater than 0.7, the electrostatic image developing toner provided by this scheme can suppress the generation of color stripes caused by leakage of the toner or external additive from the cleaning scraper of the intermediate transfer body.

[0044] According to the above-mentioned second scheme, a color tone for electrostatic image development is provided. Compared with an electrostatic image developing toner in which the content of layered structure compound particles is less than 0.1 mass % or greater than 2.0 mass % relative to the entire electrostatic image developing toner, the electrostatic image developing toner provided by this scheme can suppress the generation of color stripes caused by leakage of toner or external additives from a cleaning blade of an intermediate transfer body.

[0045] According to the third scheme, a toner for electrostatic image development is provided. Compared with an electrostatic image development toner in which the content of layered structure compound particles is less than 0.1% by mass or greater than 1.0% by mass relative to the entire electrostatic image development toner, the electrostatic image development toner provided by the scheme can suppress the generation of color stripes caused by leakage of toner or external additives from a cleaning blade of an intermediate transfer body.

[0046] According to the fourth aspect, there is provided a toner for electrostatic image development, wherein the crystallite diameter of the layered compound particles is less than or greater than The electrostatic image developing toner provided by the embodiment can suppress the generation of color streaks caused by leakage of toner or external additive from a cleaning blade of an intermediate transfer body, compared with the electrostatic image developing toner of the embodiment.

[0047] According to the above-mentioned scheme 5, a toner for electrostatic image development is provided. Compared with the toner for electrostatic image development in which the number average particle size Dn of layered structure compound particles is less than 0.3μm or greater than 1.8μm, the toner for electrostatic image development provided by this scheme can suppress the generation of color stripes caused by leakage of toner or external additives from the cleaning scraper of the intermediate transfer body.

[0048] According to the above-mentioned sixth scheme, a toner for electrostatic image development is provided. Compared with a toner for electrostatic image development in which the ratio Dn / Dv of the number average particle size Dn of layered structure compound particles to the volume average particle size Dv of toner particles is less than 0.05 or greater than 0.6, the toner for electrostatic image development provided by this scheme can suppress the generation of color stripes caused by leakage of toner or external additives from the cleaning scraper of the intermediate transfer body.

[0049] According to the tenth aspect, there is provided an electrostatic image developer, which comprises toner particles and layered compound particles, wherein the crystallite diameter of the layered compound particles is less than or greater than Or the number average particle size Dn of the layered structure compound particles is less than 0.3μm or greater than 2.0μm, or the ratio Dn / Dv of the number average particle size Dn of the layered structure compound particles to the volume average particle size Dv of the toner particles is less than 0.03 or greater than 0.7. The electrostatic image developer provided by this scheme can suppress the generation of color stripes caused by leakage of toner or external additives from the cleaning scraper of the intermediate transfer body.

[0050] According to the eleventh aspect, there is provided a toner cartridge, wherein a toner for electrostatic image development comprises toner particles and layered compound particles, wherein the crystallite diameter of the layered compound particles is less than or greater than Or the number average particle size Dn of the layered structure compound particles is less than 0.3μm or greater than 2.0μm, or the ratio Dn / Dv of the number average particle size Dn of the layered structure compound particles to the volume average particle size Dv of the toner particles is less than 0.03 or greater than 0.7. The toner box provided by this scheme can suppress the generation of color stripes caused by leakage of toner or external additives from the cleaning scraper of the intermediate transfer body.

[0051] According to the twelfth aspect, there is provided a process cartridge, wherein a toner for electrostatic image development comprises toner particles and layered compound particles, wherein the crystallite diameter of the layered compound particles is less than or greater than Or the number average particle size Dn of the layered structure compound particles is less than 0.3μm or greater than 2.0μm, or the ratio Dn / Dv of the number average particle size Dn of the layered structure compound particles to the volume average particle size Dv of the toner particles is less than 0.03 or greater than 0.7. The processing box provided by this scheme can suppress the generation of color stripes caused by leakage of toner or external additives from the cleaning scraper of the intermediate transfer body.

[0052] According to the thirteenth aspect, there is provided an image forming apparatus, wherein a toner for electrostatic image development comprises toner particles and layered compound particles, wherein the crystallite diameter of the layered compound particles is less than or greater than Or the number average particle size Dn of the layered structure compound particles is less than 0.3μm or greater than 2.0μm, or the ratio Dn / Dv of the number average particle size Dn of the layered structure compound particles to the volume average particle size Dv of the toner particles is less than 0.03 or greater than 0.7. The image forming device provided by this scheme can suppress the generation of color stripes caused by leakage of toner or external additives from the cleaning scraper of the intermediate transfer body.

[0053] According to the above-mentioned 14th aspect, there is provided an image forming method, wherein a toner for electrostatic image development comprises toner particles and layered structure compound particles, wherein the crystallite diameter of the layered structure compound particles is less than or greater than Or the number average particle size Dn of the layered structure compound particles is less than 0.3μm or greater than 2.0μm, or the ratio Dn / Dv of the number average particle size Dn of the layered structure compound particles to the volume average particle size Dv of the toner particles is less than 0.03 or greater than 0.7. The image forming method provided by this scheme can suppress the generation of color stripes caused by leakage of toner or external additives from the cleaning scraper of the intermediate transfer body. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a schematic structural diagram showing an example of the image forming apparatus according to the present embodiment.

[0055] Figure 2 This is a schematic structural diagram showing an example of a process cartridge that is attached to and detached from the image forming apparatus according to the present embodiment. DETAILED DESCRIPTION

[0056] The following describes embodiments of the present invention. These descriptions and examples are intended to illustrate the embodiments and do not limit the scope of the embodiments.

[0057] In the present invention, the numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the minimum value and the maximum value, respectively.

[0058] In the numerical range recorded in stages among the present invention, the upper limit or lower limit recorded in a numerical range can be replaced by the upper limit or lower limit of the numerical range in other stages recorded. In addition, in the numerical range recorded in the present invention, the upper limit or lower limit of this numerical range can be replaced by the value shown in the embodiment.

[0059] The term "step" in the present invention includes not only an independent step but also a step that cannot be clearly distinguished from other steps as long as the intended purpose of the step can be achieved.

[0060] When the embodiments of the present invention are described with reference to the drawings, the configuration of the embodiments is not limited to the configuration shown in the drawings. In addition, the sizes of the components in the drawings are schematic, and the relative relationship between the sizes of the components is not limited to this.

[0061] Each component in the present invention may contain two or more corresponding substances. When referring to the amount of each component in the composition of the present invention, if there are two or more substances corresponding to each component in the composition, unless otherwise stated, it refers to the total amount of the two or more substances present in the composition.

[0062] The particles corresponding to each component in the present invention may include two or more kinds of particles. When two or more kinds of particles corresponding to each component are present in the composition, unless otherwise stated, the particle size of each component refers to the value for the mixture of the two or more kinds of particles present in the composition.

[0063] In the present invention, “toner for developing an electrostatic image” is also simply referred to as “toner”, and “developer for developing an electrostatic image” is also simply referred to as “developer”.

[0064] <Toner for Electrostatic Image Development>

[0065] The toner of this embodiment includes toner particles and layered compound particles, and the layered compound particles have a crystallite diameter (crystallite diameter) of above The number average particle diameter Dn is 0.3 μm or more and 2.0 μm or less, and the ratio Dn / Dv of the number average particle diameter Dn of the layered structure compound particles to the volume average particle diameter Dv of the toner particles is 0.03 or more and 0.7 or less.

[0066] The toner of the present embodiment can suppress the occurrence of color streaks caused by leakage of toner or external additives from the cleaning blade of the intermediate transfer body. The mechanism is presumed to be as follows.

[0067] Conventionally, toners with added layered compound particles (e.g., melamine cyanurate particles, boron nitride particles) are known. The layered compound particles have an interlayer distance of angstroms. The compound particles of the layered structure are believed to exhibit a lubricating effect by the mutual slipping (slipping) between the layers. A part of the layered compound particles added to the toner acts as a lubricant at the contact portion between the image holder and the cleaning blade, and a part of the layered compound particles acts as a lubricant at the contact portion between the intermediate transfer body and the cleaning blade.

[0068] In addition, since the intermediate transfer body is a component with high smoothness and low friction coefficient, a relatively high pressure is applied to the cleaning blade in order to clean the intermediate transfer body well. As a result, at the contact portion between the intermediate transfer body and the cleaning blade, the layered structure compound particles are compressed against each other, and agglomerates of the layered structure compound particles are generated. It is speculated that since the agglomerates of the layered structure compound particles do not show lubricating properties, the toner or external additive (including the agglomerates of the layered structure compound particles) leaks out from the cleaning blade, and color stripes are generated in the image. In particular, in the case of continuous imaging of high-density images for a long time, it is speculated that since a relatively large amount of layered structure compound particles are supplied to the contact portion between the intermediate transfer body and the cleaning blade, agglomerates of the layered structure compound particles are easily generated, and as a result, the agglomerates leaking from the cleaning blade increase, and color stripes are more likely to be generated.

[0069] In contrast, when the crystallite diameter and particle diameter of the layered structure compound particles are within an appropriate range, and the ratio of the particle diameter of the layered structure compound particles to the particle diameter of the colorant particles is within an appropriate range, it is speculated that the lubricating effect of the layered structure compound particles is more effectively exerted at the contact portion between the intermediate transfer body and the cleaning scraper, thereby suppressing the generation of color stripes.

[0070] The crystallite diameter of the layered compound particles is smaller than or greater than When the layers are not easily slipped, it is estimated that the lubrication effect of each layered compound particle is insufficient. From the perspective of improving the lubrication effect of each layered compound particle, the crystallite diameter of the layered compound particle is preferably above The following, more preferably above The following is more preferably above The following, more preferably above the following.

[0071] When the number average particle size Dn of the layered structure compound particles is less than 0.3 μm, it is estimated that the distance of slip between the layers is short, and the lubrication effect shown by each layered structure compound particle is insufficient. From the perspective of improving the lubrication effect of each layered structure compound particle, the number average particle size Dn of the layered structure compound particles is 0.3 μm or more, more preferably 0.5 μm or more, and further preferably 0.7 μm or more.

[0072] When the number average particle size Dn of the layered structure compound particles is greater than 2.0 μm, it is estimated that the layered structure compound particles are easily separated from the surface of the toner particles, a large amount of layered structure compound particles remain on the image holder, and the amount of layered structure compound particles supplied to the intermediate transfer body is reduced. From the perspective of supplying the layered structure compound particles to the intermediate transfer body, the number average particle size Dn of the layered structure compound particles is 2.0 μm or less, more preferably 1.8 μm or less, further preferably 1.7 μm or less, and further preferably 1.5 μm or less.

[0073] When the ratio Dn / Dv of the number average particle diameter Dn of the layered structure compound particles to the volume average particle diameter Dv of the toner particles is less than 0.03, it is estimated that the layered structure compound particles are too small relative to the toner particles, and the layered structure compound particles are buried on the surface of the toner particles and are not easily supplied to the intermediate transfer body. From the perspective of suppressing the burial of the layered structure compound particles on the surface of the toner particles, the ratio Dn / Dv is 0.03 or more, more preferably 0.05 or more, and further preferably 0.1 or more.

[0074] When the ratio Dn / Dv of the number average particle size Dn of the layered structure compound particles to the volume average particle size Dv of the toner particles is greater than 0.7, it is estimated that the layered structure compound particles are too large relative to the toner particles, the layered structure compound particles are easily separated from the surface of the toner particles, a large amount of layered structure compound particles remain on the image holder, and the amount of layered structure compound particles supplied to the intermediate transfer body is reduced. From the perspective of supplying the layered structure compound particles to the intermediate transfer body, the ratio Dn / Dv is 0.7 or less, more preferably 0.6 or less, further preferably 0.5 or less, and further preferably 0.4 or less.

[0075] The components, structure, and characteristics of the toner according to this embodiment are described in detail below.

[0076] [Toner particles]

[0077] The toner particles are constituted by, for example, containing a binding resin and, if necessary, a colorant, a release agent, and other additives.

[0078] - Adhesive resin -

[0079] As the adhesive resin, for example, there can be mentioned vinyl resins formed by homopolymers of the following monomers or copolymers of two or more of these monomers, the monomers being: styrenes (for example, styrene, p-chlorostyrene, α-methylstyrene, etc.), (meth)acrylates (for example, 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 (for example, acrylonitrile, methacrylonitrile, etc.), vinyl ethers (for example, vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (for example, ethylene, propylene, butadiene, etc.), etc.

[0080] Examples of the adhesive resin include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosins, mixtures of these resins with the above-mentioned vinyl resins, or graft polymers obtained by polymerizing vinyl monomers in the coexistence of these resins.

[0081] These adhesive resins may be used alone or in combination of two or more.

[0082] As the adhesive resin, a polyester resin is suitable.

[0083] As the polyester resin, for example, a known amorphous polyester resin can be cited. Among the polyester resins, the amorphous polyester resin can also be used together with a crystalline polyester resin. Among them, the crystalline polyester resin can be used in a content of 2% by mass to 40% by mass (preferably 2% by mass to 20% by mass) relative to the total binder resin.

[0084] The "crystallinity" of a resin means that there is no step-like change in endothermic value in differential scanning calorimetry (DSC) and that the resin has a clear endothermic peak. Specifically, the half-width of the endothermic peak is within 10°C when measured at a heating rate of 10 (°C / min).

[0085] On the other hand, the "amorphous" nature of a resin means that the half-peak width is larger than 10°C, the endothermic quantity changes stepwise, or no clear endothermic peak is observed.

[0086] Amorphous polyester resin

[0087] Examples of the non-crystalline polyester resin include polycondensates of polycarboxylic acids and polyols. As the non-crystalline polyester resin, a commercially available product may be used, or a synthetic product may be used.

[0088] Examples of the polycarboxylic acid 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.), 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.

[0089] Among the polycarboxylic acids, dicarboxylic acids and trivalent or higher carboxylic acids having a crosslinked structure or a branched structure may be used in combination. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, their anhydrides, or their lower (e.g., carbon number 1 to 5) alkyl esters.

[0090] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0091] Examples of the polyol include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, 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, the polyol is preferably an aromatic diol or an alicyclic diol, and more preferably an aromatic diol.

[0092] As the polyol, a diol may be used in combination with a trivalent or higher polyol having a crosslinked structure or a branched structure. Examples of the trivalent or higher polyol include glycerin, trimethylolpropane, and pentaerythritol.

[0093] The polyols may be used alone or in combination of two or more.

[0094] The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50°C to 80°C, and more preferably 50°C to 65°C.

[0095] The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), more specifically, by "extrapolated glass transition start temperature" described in the method for measuring glass transition temperature in JIS K7121:1987 "Method for measuring transition temperature of plastics".

[0096] The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 to 1,000,000, and more preferably 7,000 to 500,000.

[0097] The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2,000 or more and 100,000 or less.

[0098] The molecular weight distribution Mw / Mn of the amorphous polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less.

[0099] The weight average molecular weight and the number average molecular weight were measured by gel permeation chromatography (GPC). In the molecular weight measurement using GPC, a Tosoh GPC HLC-8120GPC was used as a measuring device, a Tosoh column TSKgel SuperHM-M (15 cm) was used, and the measurement was performed using THF solvent. The weight average molecular weight and the number average molecular weight were calculated based on the measurement results using a molecular weight calibration curve prepared using a monodisperse polystyrene standard sample.

[0100] 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 or alcohol generated during condensation.

[0101] When the monomer of the raw material is insoluble or incompatible at the reaction temperature, a high boiling point solvent may be added as a dissolving aid to dissolve it. In this case, the polycondensation reaction is carried out while the dissolving aid is distilled off. When there are monomers with poor compatibility in the copolymerization reaction, the monomers with poor compatibility may be condensed with a specific acid or alcohol that is polycondensed with the monomer in advance, and then polycondensed with the main component.

[0102] Crystalline polyester resin

[0103] Examples of the crystalline polyester resin include polycondensates of polycarboxylic acids and polyols. As the crystalline polyester resin, a commercially available product may be used, or a synthetic product may be used.

[0104] Here, in order to make the crystalline polyester resin easily form a crystal structure, the crystalline polyester resin is preferably a polycondensate obtained using a linear aliphatic polymerizable monomer rather than a polycondensate obtained using a polymerizable monomer having an aromatic ring.

[0105] Examples of the polycarboxylic acid 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.), anhydrides thereof, or lower (e.g., carbon number 1 to 5) alkyl esters thereof.

[0106] Among the polycarboxylic acids, dicarboxylic acids and trivalent or higher carboxylic acids having a crosslinked structure or a branched structure may be used in combination. Examples of trivalent carboxylic acids 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.

[0107] As the polycarboxylic acid, these dicarboxylic acids may be used in combination with a dicarboxylic acid having a sulfonic acid group or a dicarboxylic acid having an ethylenic double bond.

[0108] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0109] Examples of the polyol include aliphatic diols (e.g., linear aliphatic diols having a main chain portion having 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-eicosandiol. Among these, preferred aliphatic diols include 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol.

[0110] Among the polyols, diols may be used in combination with trivalent or higher alcohols having a crosslinked structure or a branched structure. Examples of the trivalent or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.

[0111] The polyols may be used alone or in combination of two or more.

[0112] Here, the content of the aliphatic diol in the polyol is preferably 80 mol % or more, and preferably 90 mol % or more.

[0113] The melting temperature of the crystalline polyester resin is preferably 50°C to 100°C, more preferably 55°C to 90°C, and even more preferably 60°C to 85°C.

[0114] The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) by the “melting peak temperature” described in the method for measuring melting temperature in JIS K7121:1987 “Method for measuring transition temperatures of plastics”.

[0115] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

[0116] The crystalline polyester resin can be obtained, for example, by a known production method similar to the amorphous polyester.

[0117] The content of the binder resin is preferably 40% by mass to 95% by mass, more preferably 50% by mass to 90% by mass, and further preferably 60% by mass to 85% by mass, based on the entire toner particles.

[0118] -Colorants-

[0119] Examples of the colorant include carbon black, chrome yellow, Hansa yellow, benzidine yellow, vat yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, sulfur-resistant orange, Vochug red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont Oil Red, pyrazolone red, litho red, rhodamine B lake, lake red C, pigment red, rose red, aniline blue, ultramarine blue, oil-soluble blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, malachite green oxalate and other pigments; and dyes such as acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindigo, dioxazine, thiazine, azomethine, indigo, phthalocyanine, nigrosine, polymethine, triphenylmethane, diphenylmethane and thiazole.

[0120] The coloring agent may be used alone or in combination of two or more.

[0121] The colorant may be a colorant that has been subjected to surface treatment as required, or may be used in combination with a dispersant. In addition, two or more colorants may be used in combination.

[0122] The content of the colorant is preferably from 1 mass % to 30 mass % both inclusive, and more preferably from 3 mass % to 15 mass % both inclusive, based on the entire toner particles.

[0123] -Release agent-

[0124] 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 and petroleum waxes, and ester waxes such as fatty acid esters and montanic acid esters. The release agent is not limited thereto.

[0125] The melting temperature of the release agent is preferably 50°C to 110°C, more preferably 60°C to 100°C.

[0126] The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) by the “melting peak temperature” described in the method for measuring melting temperature in JIS K7121:1987 “Method for measuring transition temperatures of plastics”.

[0127] The content of the release agent is preferably from 1 mass % to 20 mass % both inclusive, and more preferably from 5 mass % to 15 mass % both inclusive, based on the entire toner particles.

[0128] -Other additives-

[0129] Examples of other additives include known additives such as magnetic materials, charge control agents, and inorganic powders. These additives may be contained in the toner particles as internal additives.

[0130] -Characteristics of toner particles, etc.-

[0131] 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 portion (core particle) and a coating layer (shell layer) that covers the core portion.

[0132] The toner particles of a core / shell structure may be composed of, for example, a core portion including a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer including a binder resin.

[0133] From the perspective of suppressing the occurrence of color streaks due to poor cleaning of the intermediate transfer body, the volume average particle size Dv of the toner particles is preferably 3.0 μm to 10.0 μm, more preferably 3.5 μm to 7.0 μm, and even more preferably 4.0 μm to 6.0 μm.

[0134] The volume average particle size Dv of the toner particles is measured using Coulter Multisizer II (manufactured by Beckman Coulter) and ISOTON-II (manufactured by Beckman Coulter) for the electrolyte. In the measurement, 0.5 mg to 50 mg of the measurement sample is added to 2 ml of a 5% by mass aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate) as a dispersant. The sample is then added to 100 ml to 150 ml of the electrolyte.

[0135] The electrolyte in which the sample is suspended is dispersed for 1 minute using an ultrasonic disperser, and the particles with a particle size of 2 μm or more and 60 μm or less are measured using a Coulter Multisizer II with a hole of 100 μm in diameter. The number of particles sampled is 50,000. The cumulative distribution of the particle size is drawn from the small diameter side on a volume basis, and the particle size at the cumulative 50% point is taken as the volume average particle size Dv.

[0136] The average circularity of the toner particles is preferably from 0.94 to 1.00, and more preferably from 0.95 to 0.98.

[0137] The average circularity of the toner particles is calculated by (equivalent circular circumference) / (circumference) [(circumference of a circle having the same projected area as the particle image) / (circumference of the particle projected image)]. Specifically, it is a value measured by the following method.

[0138] First, the toner particles to be measured are collected by suction and formed into a flat flow, and the particles are momentarily strobed to obtain a particle image as a still image, and the particle image is analyzed by a flow particle image analyzer (FPIA-3000 manufactured by Sysmex) to obtain the average circularity. The number of samples for obtaining the average circularity is set to 3500.

[0139] When the toner has an external additive, the toner (developer) to be measured is dispersed in water containing a surfactant and then subjected to ultrasonic treatment to obtain toner particles from which the external additive has been removed.

[0140] [Layered compound particles]

[0141] The layered compound particles are particles of a compound having a layered structure. Examples of the layered compound particles include melamine cyanurate particles, boron nitride particles, graphite fluoride particles, molybdenum disulfide particles, and mica particles.

[0142] From the viewpoint of suppressing the occurrence of color streaks due to poor cleaning of the intermediate transfer member, the crystallite diameter of the layered compound particles is preferably above The following, more preferably above The following is more preferably above The following, more preferably above the following.

[0143] The crystallite diameter of the layered structure compound particles can be controlled by heating the layered structure compound particles. The heating is performed, for example, at 50°C to 400°C for 10 minutes to 20 minutes. The higher the temperature at which the layered structure compound particles are heated, the smaller the crystallite diameter is, and the longer the heating time is, the smaller the crystallite diameter is.

[0144] The crystallite diameter of the layered structure compound particles is determined from the maximum peak width of the CuKα-ray X-ray diffraction pattern according to the Scherrer formula.

[0145] Scherrer formula···D=Kλ / (βcosθ)

[0146] Here, D is the crystallite diameter, K is a constant of 0.9, and λ is the wavelength of the CuKα ray. β is the full width at half maximum of the maximum peak, and θ is the Bragg angle (half of the diffraction angle 2θ of the maximum peak).

[0147] CuKα-ray X-ray diffraction of the layered structure compound particles was performed as follows.

[0148] The X-ray diffraction device (e.g., manufactured by Rigaku Corporation, trade name RINT Ultima-III) is set to measure, i.e., ray source CuKα, voltage 40 kV, current 40 mA, sample rotation speed: no rotation, divergence slit: 1.00 mm, divergence longitudinal limit slit: 10 mm, scattering slit: open, light receiving slit: open, scanning mode: FT, counting time: 2.0 seconds, step width: 0.050°, operating axis: 10.0000° to 70.0000°. In the present invention, the half-peak width of the peak in the X-ray diffraction pattern is the full width at half maximum.

[0149] From the perspective of suppressing the generation of color stripes caused by poor cleaning of the intermediate transfer body, the number average particle size Dn of the layered structure compound particles is 0.3 μm to 2.0 μm, more preferably 0.3 μm to 1.8 μm, further preferably 0.5 μm to 1.8 μm, further preferably 0.5 μm to 1.7 μm, further preferably 0.7 μm to 1.5 μm. The number average particle size of the layered structure compound particles can be controlled by pulverization, classification, or a combination of pulverization and classification.

[0150] The number average particle size Dn of the layered structure compound is determined by the following measurement method.

[0151] First, the layered structure compound particles are separated from the toner. There is no limitation on the method for separating the layered structure compound particles from the toner. For example, the toner is dispersed in water containing a surfactant and ultrasonic waves are applied to the obtained dispersion. The dispersion is then centrifuged at high speed to centrifuge the toner particles, the layered structure compound particles, and other external additives according to their specific gravity. The fraction containing the layered structure compound particles is extracted and dried to obtain the layered structure compound particles.

[0152] Next, the layered structure compound particles are added to an electrolyte aqueous solution (isotonic aqueous solution), and ultrasonic waves are applied for more than 30 seconds to disperse them. The dispersion is used as a sample, and the particle size is measured using a laser diffraction scattering particle size distribution measuring device (e.g., Microtrac BEL, Microtrac MT3000II). At least 3,000 layered structure compound particles are measured, and the particle size at the cumulative 50% point from the small diameter side in the number-based particle size distribution is taken as the number average particle size Dn.

[0153] From the perspective of suppressing the occurrence of color stripes caused by poor cleaning of the intermediate transfer body, the content of the layered structure compound particles is preferably 0.1 mass % to 2.0 mass %, more preferably 0.1 mass % to 1.0 mass %, and further preferably 0.1 mass % to 0.5 mass %, relative to the entire toner.

[0154] [External Additives]

[0155] Examples of external additives include inorganic particles, such as SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, and MgSO4.

[0156] The surface of the inorganic particles as an external additive is suitably subjected to hydrophobization. Hydrophobization is carried out by, for example, immersing the inorganic particles in a hydrophobization treatment agent. There is no particular limitation on the hydrophobization treatment agent, and for example, silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents, etc. can be cited. These treatment agents can be used alone or in combination of two or more. About the amount of the hydrophobization treatment agent, for example, relative to 100 mass parts of inorganic particles, it is usually 1 mass part or more and 10 mass parts or less.

[0157] Examples of the external additives include resin particles (polystyrene, polymethyl methacrylate, melamine resin, and other resin particles), detergent active agents (metal salts of higher fatty acids such as zinc stearate, and particles of fluorine-based high molecular weight bodies).

[0158] The amount of the external additive added is preferably 0.01% by mass or more and 5% by mass or less, and more preferably 0.01% by mass or more and 2.0% by mass or less, based on the toner particles.

[0159] [Toner Manufacturing Method]

[0160] The toner according to the present embodiment is obtained by manufacturing toner particles and then adding an external additive to the toner particles.

[0161] The toner particles can be produced by any of dry methods (e.g., kneading and pulverization methods) and wet methods (e.g., aggregation and merging methods, suspension polymerization methods, dissolution and suspension methods, etc.). These methods are not particularly limited, and known methods can be used. Among these, the toner particles can be obtained by the aggregation and merging method.

[0162] Specifically, for example, in the case of manufacturing toner particles by an agglomeration and merging method, the toner particles are manufactured through the following steps: a step of preparing a resin particle dispersion in which resin particles serving as a binding resin are dispersed (resin particle dispersion preparation step); a step of agglomerating resin particles (and other particles if necessary) in the resin particle dispersion (in a dispersion after mixing other particle dispersions if necessary) to form agglomerated particles (agglomerated particle formation step); and a step of heating the agglomerated particle dispersion in which the agglomerated particles are dispersed to fuse / merge the agglomerated particles to form toner particles (fusion / merging step).

[0163] The details of each step are described below.

[0164] In the following description, a method for obtaining toner particles containing a colorant and a release agent is described, but the colorant and the release agent are additives used as needed. Of course, other additives besides the colorant and the release agent may also be used.

[0165] - Resin particle dispersion preparation step -

[0166] A resin particle dispersion in which resin particles as a binder resin are dispersed is prepared, and at the same time, for example, a colorant particle dispersion in which colorant particles are dispersed and a release agent particle dispersion in which release agent particles are dispersed are prepared.

[0167] The resin particle dispersion is prepared, for example, by dispersing the resin particles in a dispersion medium using a surfactant.

[0168] Examples of the dispersion medium used for the resin particle dispersion include aqueous media.

[0169] Examples of the aqueous medium include water such as distilled water and ion-exchanged water, alcohols, etc. These media may be used alone or in combination of two or more.

[0170] Examples of surfactants include 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; and the like. Among these, anionic surfactants and cationic surfactants can be particularly mentioned. Nonionic surfactants can also be used in combination with anionic surfactants or cationic surfactants.

[0171] The surfactant may be used alone or in combination of two or more.

[0172] In the resin particle dispersion, as a method for dispersing the resin particles in the dispersion medium, for example, a common dispersion method using a rotary shearing homogenizer or a ball mill, sand mill, bead mill, etc. with a medium can be cited. In addition, depending on the type of resin particles, the resin particles can also be dispersed in the dispersion medium using a phase inversion emulsification method. The phase inversion emulsification method is a method in which the resin to be dispersed is dissolved in a hydrophobic organic solvent that can dissolve the resin, a base is added to the organic continuous phase (O phase) for neutralization, and then an aqueous medium (W phase) is added to thereby invert the phase from W / O to O / W, so that the resin is dispersed in the aqueous medium in a particle form.

[0173] The volume average particle size of the resin particles dispersed in the resin particle dispersion is, for example, preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and further preferably 0.1 μm or more and 0.6 μm or less.

[0174] The volume average particle size of the resin particles is determined by using a particle size distribution obtained by measurement using a laser diffraction particle size distribution measuring device (e.g., LA-700 manufactured by Horiba, Ltd.). For the divided particle size range (segment), a cumulative distribution is plotted for volume from the small particle size side, and the particle size at the cumulative 50% point relative to all particles is measured, which is taken as the volume average particle size D50v. The volume average particle size of particles in other dispersions is measured in the same manner.

[0175] The content of the resin particles contained in the resin particle dispersion is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.

[0176] For example, a colorant particle dispersion and a release agent particle dispersion are prepared in the same manner as the resin particle dispersion. That is, the volume average particle size of the particles in the resin particle dispersion, the dispersion medium, the dispersion method, and the content of the particles are the same for the colorant particles dispersed in the colorant particle dispersion and the release agent particles dispersed in the release agent particle dispersion.

[0177] - Agglomerated Particle Formation Step-

[0178] Next, the resin particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mixed.

[0179] Then, the resin particles, the colorant particles, and the release agent particles are heterogeneously aggregated in the mixed dispersion to form aggregated particles containing the resin particles, the colorant particles, and the release agent particles and having a diameter close to that of the target toner particles.

[0180] Specifically, for example, a coagulant is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to acidity (for example, pH 2 to 5), a dispersion stabilizer is added as needed, and then heated to a temperature close to the glass transition temperature of the resin particles (specifically, for example, the glass transition temperature of the resin particles is -30°C to the glass transition temperature of -10°C), so that the particles dispersed in the mixed dispersion are agglomerated to form agglomerated particles.

[0181] In the aggregated particle forming step, for example, a coagulant may be added at room temperature (e.g., 25° C.) while the mixed dispersion is stirred using a rotary shearing homogenizer, the pH of the mixed dispersion is adjusted to acidic (e.g., pH 2 to 5), a dispersion stabilizer may be added as needed, and then the mixture may be heated.

[0182] Examples of the coagulant include surfactants having opposite polarity to the surfactant contained in the mixed dispersion, inorganic metal salts, and divalent or higher metal complexes. When a metal complex is used as the coagulant, the amount of surfactant used is reduced and the charging characteristics are improved.

[0183] If necessary, an additive that forms a complex or similar bond with the metal ion of the coagulant may be used together with the coagulant. As the additive, a chelating agent is preferably used.

[0184] 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.

[0185] As the chelating agent, a water-soluble chelating agent can be used. 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.

[0186] The amount of the chelating agent added is 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, based on 100 parts by mass of the resin particles.

[0187] - Fusion / Merge Steps-

[0188] Next, the aggregated particle dispersion containing the dispersed aggregated particles is heated to, for example, a temperature higher than the glass transition temperature of the resin particles (eg, 10° C. to 30° C. higher than the glass transition temperature of the resin particles) to fuse / combine the aggregated particles to form toner particles.

[0189] After the above steps, toner particles are obtained.

[0190] After obtaining a dispersion of aggregated particles dispersed therein, toner particles can be manufactured by the following steps: further mixing the dispersion of aggregated particles with a dispersion of resin particles dispersed therein, agglomerating the resin particles so as to further adhere to the surfaces of the aggregated particles to form second aggregated particles; and heating the second dispersion of aggregated particles dispersed therein to fuse / merge the second aggregated particles to form toner particles with a core / shell structure.

[0191] After the fusion / merging step is completed, the toner particles formed in the dispersion are subjected to a known washing step, a solid-liquid separation step, and a drying step to obtain dry toner particles. Regarding the washing step, from the perspective of charging performance, replacement washing using ion exchange water can be fully implemented. Regarding the solid-liquid separation step, from the perspective of productivity, suction filtration, pressure filtration, etc. can be implemented. Regarding the drying step, from the perspective of productivity, freeze drying, airflow drying, fluidized bed drying, vibration fluidized bed drying, etc. can be implemented.

[0192] Thereafter, for example, an external additive is added to the obtained dry toner particles and mixed, thereby producing the toner of the present embodiment. The mixing can be performed using, for example, a V-type blender, a Henschel mixer, a Loedige mixer, etc. Furthermore, coarse particles of the toner can be removed using a vibration sieving machine, a wind sieving machine, etc. as needed.

[0193] <Electrostatic Image Developer>

[0194] The electrostatic image developer according to the present embodiment includes at least the toner according to the present embodiment.

[0195] The electrostatic image developer of the present embodiment may be a one-component developer containing only the toner of the present embodiment, or may be a two-component developer in which the toner and a carrier are mixed.

[0196] The carrier is not particularly limited, and known carriers can be cited. Examples of the carrier include: a coated carrier in which a core material formed of magnetic powder is coated with a resin; a magnetic powder dispersion carrier in which magnetic powder is dispersed and mixed in a matrix resin; a resin impregnated carrier in which a porous magnetic powder is impregnated with a resin; and the like. The magnetic powder dispersion carrier and the resin impregnated carrier may also be a carrier in which the constituent particles of the carrier are used as a core material and the surface thereof is coated with a resin.

[0197] Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt; and magnetic oxides such as ferrite and magnetite.

[0198] Examples of the coating resin and base resin include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylate copolymer, pure silicone resin or modified products thereof containing organic siloxane bonds, fluororesins, polyesters, polycarbonates, phenolic resins, epoxy resins, etc. The coating resin and base resin may contain other additives such as conductive particles. Examples of the conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0199] When the surface of the core material is coated with a resin, it can be enumerated as follows: a method of coating with a coating layer formed by dissolving a coating resin and various additives (used as needed) in an appropriate solvent, etc. The solvent is not particularly limited and can be selected by considering the type of resin used, coating suitability, etc.

[0200] Specific resin coating methods include: an immersion method, in which the core material is immersed in a coating layer forming solution; a spray method, in which the coating layer forming solution is sprayed onto 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 coater method, in which the core material of the carrier is mixed with the coating layer forming solution in a kneading coater and then the solvent is removed; and the like.

[0201] The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is preferably toner:carrier=1:100 to 30:100, and more preferably 3:100 to 20:100.

[0202] <Image Forming Apparatus, Image Forming Method>

[0203] An image forming apparatus and an image forming method according to the present embodiment will be described.

[0204] The image forming apparatus of the present embodiment comprises: an image holder; a charging mechanism for charging the surface of the image holder; an electrostatic image forming mechanism for forming an electrostatic image on the surface of the charged image holder; a developing mechanism for storing an electrostatic image developer and developing the electrostatic image formed on the surface of the image holder into a toner image using the electrostatic image developer; an intermediate transfer body for transferring the toner image formed on the surface of the image holder; a primary transfer mechanism for transferring the toner image formed on the surface of the image holder to the surface of the intermediate transfer body; a secondary transfer mechanism for transferring the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium; a fixing mechanism for fixing the toner image transferred to the surface of the recording medium; and a cleaning mechanism having a scraper in contact with the surface of the intermediate transfer body, and using the scraper to clean the toner remaining on the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium. The electrostatic image developer of the present embodiment is used as the electrostatic image developer.

[0205] The image forming device of the present embodiment implements an image forming method (the image forming method of the present embodiment), which has the following steps: a charging step, charging the surface of the image retaining body; an electrostatic image forming step, forming an electrostatic image on the charged surface of the image retaining body; a developing step, using the electrostatic image developer of the present embodiment to develop the electrostatic image formed on the surface of the image retaining body into a toner image; a primary transfer step, transferring the toner image formed on the surface of the image retaining body to the surface of the intermediate transfer body; a secondary transfer step, transferring the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium; a fixing step, fixing the toner image transferred to the surface of the recording medium; and a cleaning step, bringing the scraper into contact with the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium, and cleaning the toner remaining on the surface of the intermediate transfer body.

[0206] The image forming device of this embodiment is applicable to the following well-known image forming devices: a device having a cleaning mechanism for cleaning the surface of an image holding body after a primary transfer and before charging; a device having a static elimination mechanism for eliminating static by irradiating the surface of an image holding body with static eliminating light after a primary transfer and before charging; and the like.

[0207] In the image forming apparatus of this embodiment, for example, the part including the developing mechanism may be a cartridge structure (processing cartridge) that is detachable from the image forming apparatus. As the processing cartridge, for example, a processing cartridge that stores the electrostatic image developer of this embodiment and has a developing mechanism is preferably used.

[0208] 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 the other descriptions are omitted.

[0209] Figure 1 2 is a diagram schematically showing the structure of the image forming apparatus according to the present embodiment.

[0210] Figure 1 The image forming apparatus shown in the figure is provided with first to fourth image forming units 10Y, 10M, 10C, 10K (image forming mechanism) of the electrophotographic method for outputting images of yellow (Y), magenta (M), cyan (C), and black (K) colors based on color separation image data. These image forming units (hereinafter sometimes 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.

[0211] Above each unit 10Y, 10M, 10C, 10K, an intermediate transfer belt (an example of an intermediate transfer body) 20 is extended through each unit. The intermediate transfer belt 20 is wound around a driving roller 22 and a supporting roller 24 so as to run in a direction from the first unit 10Y to the fourth unit 10K. The supporting roller 24 is biased in a direction away from the driving roller 22 by a spring (not shown) or the like, and tension is applied to the intermediate transfer belt 20 wound around the two. An intermediate transfer body cleaning device (an example of an intermediate transfer body cleaning mechanism) 30 is provided on the image holding body side of the intermediate transfer belt 20, which is opposed to the driving roller 22.

[0212] The intermediate transfer belt 20 is, for example, a laminate of a base layer and a surface layer disposed on the outer peripheral surface of the base layer. The base layer includes, for example, a resin such as a polyimide resin, a polyamide resin, a polyamide-imide resin, a polyether ester resin, a polyarylate resin, a polyester resin, and a conductive agent. The surface layer includes, for example, at least one of the above resins, a fluororesin, and a conductive agent. The thickness of the intermediate transfer belt 20 is, for example, not less than 50 μm and not more than 100 μm.

[0213] Yellow, magenta, cyan and black toners stored in toner cartridges 8Y, 8M, 8C and 8K are supplied to developing devices (an example of developing mechanisms) 4Y, 4M, 4C and 4K of the respective units 10Y, 10M, 10C and 10K.

[0214] The first to fourth units 10Y, 10M, 10C, and 10K have the same configuration and operation, and therefore the first unit 10Y disposed on the upstream side in the running direction of the intermediate transfer belt and forming a yellow image will be described as a representative.

[0215] 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 mechanism) 2Y that charges the surface of the photoreceptor 1Y to a preset potential; an exposure device (an example of an electrostatic image forming mechanism) 3 that forms an electrostatic image by exposing the charged surface using a laser beam 3Y based on a color separation image signal; a developing device (an example of a developing mechanism) 4Y that supplies the charged toner to the electrostatic image to develop the electrostatic image; a primary transfer roller 5Y (an example of a primary transfer mechanism) that transfers the developed toner image to the intermediate transfer belt 20; and a photoreceptor cleaning device (an example of a cleaning mechanism) 6Y that removes the toner remaining on the surface of the photoreceptor 1Y after the primary transfer.

[0216] The primary transfer roller 5Y is arranged inside the intermediate transfer belt 20 and is provided at a position facing the photosensitive body 1Y. The primary transfer rollers 5Y, 5M, 5C, and 5K of each unit are connected to bias power supplies (not shown) for applying primary transfer bias. 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).

[0217] The photoreceptor cleaning device 6Y includes a cleaning blade that contacts the surface of the photoreceptor 1Y. The cleaning blade contacts the surface of the photoreceptor 1Y that continues to rotate after the toner image is transferred to the intermediate transfer belt 20, and removes the toner remaining on the surface of the photoreceptor 1Y.

[0218] A secondary transfer roller (an example of a secondary transfer mechanism) 26 and a support roller 24 are provided downstream of the fourth unit 10K. The secondary transfer roller 26 is arranged on the image holding surface side of the intermediate transfer belt 20, and the support roller 24 is arranged in contact with the inner surface of the intermediate transfer belt 20. The secondary transfer roller 26 and the support roller 24 constitute a secondary transfer section.

[0219] The intermediate transfer cleaning device 30 includes a cleaning blade that contacts the surface of the intermediate transfer belt 20. The cleaning blade contacts the surface of the intermediate transfer belt 20 that continues to run after the toner image is transferred to the recording medium, and removes the toner remaining on the surface of the intermediate transfer belt 20. Examples of the material of the cleaning blade include thermosetting polyurethane rubber, silicone rubber, fluororubber, ethylene-propylene-diene rubber, and the like. The thickness of the cleaning blade is, for example, not less than 1 mm and not more than 7 mm.

[0220] Next, the operation of forming a yellow image in the first unit 10Y will be described.

[0221] First, before the operation, the surface of the photoreceptor 1Y is charged to a potential of -600 V to -800 V by the charging roller 2Y.

[0222] The photoreceptor 1Y has a conductivity (e.g., 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 Ωcm or less. The photosensitive layer generally has a high resistance (resistance of a common resin), but has a property that the resistivity of the portion irradiated with the laser beam changes when the laser beam is irradiated. Therefore, according to the yellow image data sent from the control unit (not shown), the laser beam 3Y is irradiated from the exposure device 3 to the charged surface of the photoreceptor 1Y. As a result, an electrostatic image of a yellow image pattern is formed on the surface of the photoreceptor 1Y.

[0223] The electrostatic image is an image formed on the surface of the photoreceptor 1Y by charging, which is a so-called negative latent image. The negative latent image is formed as follows: the resistivity of the irradiated portion of the photosensitive layer is reduced by using the laser beam 3Y, so that the charged charge on the surface of the photoreceptor 1Y flows; on the other hand, the charge of the portion not irradiated with the laser beam 3Y remains, thereby forming the negative latent image.

[0224] The electrostatic image formed on the photoreceptor 1Y rotates to a preset development position as the photoreceptor 1Y runs. At the development position, the electrostatic image on the photoreceptor 1Y is developed into a toner image by the developing device 4Y and visualized.

[0225] The developing device 4Y stores an electrostatic image developer containing, for example, at least a yellow toner and a carrier. The yellow toner is frictionally charged by being stirred inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charge charged on the photoreceptor 1Y, and is held on the developer roller (an example of a developer holding member). After that, the surface of the photoreceptor 1Y passes through the developing device 4Y, whereby the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y that has been de-charged, and the latent image is developed using the yellow toner. The photoreceptor 1Y formed with the yellow toner image continues to run at a preset speed, and the toner image developed on the photoreceptor 1Y is conveyed to a preset primary transfer position.

[0226] When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer roller 5Y, and the 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 to, for example, +10 μA by a control section (not shown) in the first unit 10Y.

[0227] The photoreceptor 1Y, after transferring the toner image to the intermediate transfer belt 20, continues to rotate and contacts a cleaning blade provided in the photoreceptor cleaning device 6Y. The toner remaining on the photoreceptor 1Y is removed and recovered by the photoreceptor cleaning device 6Y.

[0228] The primary transfer bias applied to the primary transfer rollers 5M, 5C, and 5K after the second unit 10M is also controlled in accordance with the first unit.

[0229] In this way, the intermediate transfer belt 20 to which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, so that the toner images of the respective colors are multi-transferred in a superimposed manner.

[0230] The intermediate transfer belt 20 to which the four-color toner image has been multi-transferred by the first to fourth units arrives at the secondary transfer section, which is composed of the intermediate transfer belt 20, the support roller 24 in contact with the inner surface of the intermediate transfer belt, and the secondary transfer roller 26 arranged on the image holding surface side of the intermediate transfer belt 20. On the other hand, the recording paper (an example of a recording medium) P is fed to the gap between the secondary transfer roller 26 and the intermediate transfer belt 20 at a preset timing by the feeding member, and a 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 to 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 mechanism (not shown) that detects the resistance of the secondary transfer section, and the voltage is controlled.

[0231] After the toner image is transferred to the recording paper P, the intermediate transfer belt 20 continues to run and contacts the cleaning blade of the intermediate transfer body cleaning device 30. The toner remaining on the intermediate transfer belt 20 is removed and recovered by the intermediate transfer body cleaning device 30. The contact pressure of the cleaning blade (the pressure applied to the intermediate transfer belt 20 in the thickness direction) is, for example, 1 g / mm or more and 5 g / mm or less. The contact angle of the cleaning blade is, for example, 5 degrees or more and 30 degrees or less. The contact width of the cleaning blade is, for example, 0.1 mm or more and 2 mm or less.

[0232] The recording paper P to which the toner image has been transferred is fed to a pressure-contact portion (nip portion) of a pair of fixing rollers in a fixing device (an example of a fixing mechanism) 28 , and the toner image is fixed to the recording paper P, thereby forming a fixed image.

[0233] Examples of the recording paper P to which the toner image is transferred include plain paper used in electrophotographic copy machines, printers, and the like. Examples of the recording medium include, in addition to the recording paper P, OHP transparent films and the like.

[0234] In order to further improve the smoothness of the image surface after fixing, the surface of the recording paper P is preferably smooth. For example, coated paper obtained by coating the surface of ordinary paper with a resin or the like, art paper for printing, etc. are preferably used.

[0235] The recording paper P on which the color image has been fixed is sent to the discharge portion, and a series of color image forming operations are completed.

[0236] <Process Cartridge, Toner Cartridge>

[0237] The process cartridge according to this embodiment will be described.

[0238] The processing box of the present embodiment is a processing box that is loaded and unloaded in an image forming device, and comprises: a developing mechanism that stores the electrostatic image developer of the present embodiment and uses the electrostatic image developer to develop the electrostatic image formed on the surface of the image retaining body into a toner image; an intermediate transfer body that transfers the toner image formed on the surface of the image retaining body; and a cleaning mechanism that has a scraper that contacts the surface of the intermediate transfer body, and uses the scraper to clean the toner remaining on the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium.

[0239] The process cartridge of the present embodiment is not limited to the above-described configuration, and may be further provided with at least one selected from other mechanisms such as an image holding member, a charging mechanism, and an electrostatic image forming mechanism, for example.

[0240] 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 the description of other parts is omitted.

[0241] Figure 2 This is a schematic structural diagram showing an example of a process cartridge that is attached to and detached from the image forming apparatus according to the present embodiment. Figure 2 The process cartridge 200 shown is configured by integrating a photoreceptor 107 (an example of an image holding member), a charging roller 108 (an example of a charging mechanism) provided around the photoreceptor 107, a developing device 111 (an example of a developing mechanism), and a photoreceptor cleaning device 113 (an example of an image holding member cleaning mechanism) by means of a housing 117 having a mounting guide 116 and an opening 118 for exposure, and further combining an intermediate transfer belt 120 (an example of an intermediate transfer member), a primary transfer roller 121 (an example of a primary transfer mechanism), a secondary transfer roller 122 (an example of a secondary transfer mechanism), a support roller 123, a driving roller 124, and an intermediate transfer member cleaning device 125 (an example of an intermediate transfer member cleaning mechanism). The photoreceptor cleaning device 113 includes a scraper that contacts the photoreceptor 107. The intermediate transfer member cleaning device 125 includes a scraper that contacts the intermediate transfer belt 120. When the photoreceptor 107 is placed in an image forming apparatus and performs image formation, it is exposed by an exposure device 109 (an example of an electrostatic image forming mechanism) to form an electrostatic image on the surface.

[0242] Next, the toner cartridge according to the present embodiment will be described.

[0243] The toner cartridge of the present embodiment stores the toner of the present embodiment and is attached to and detached from the image forming apparatus. The toner cartridge stores replenishment toner to be supplied to a developing mechanism provided in the image forming apparatus.

[0244] Figure 1 The image forming apparatus shown is an image forming apparatus having a structure of 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) by toner supply pipes not shown. When the toner stored in the toner cartridge is insufficient, the toner cartridge is replaced.

[0245] Example

[0246] The embodiments disclosed in the examples are described in detail below, but the disclosed embodiments are not limited to these examples. In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0247] <Preparation of Toner Particles (1)>

[0248] [Preparation of amorphous polyester resin dispersion (A1)]

[0249] Terephthalic acid: 70 parts

[0250] Fumaric acid: 30 parts

[0251] Ethylene glycol: 44 parts

[0252] 1,5-Pentanediol: 46 parts

[0253] 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 was raised to 210°C in 1 hour under a nitrogen flow. 1 part of tetraethoxytitanium was added to 100 parts of the above materials in total. The temperature was raised to 240°C in 0.5 hours while distilling off the generated water. After the dehydration condensation reaction was continued at 240°C for 1 hour, the reactant was cooled. In this way, an amorphous polyester resin with a weight average molecular weight of 94,500 and a glass transition temperature of 61°C was obtained.

[0254] After 40 parts of ethyl acetate and 25 parts of 2-butanol were added to a container equipped with a temperature control mechanism and a nitrogen replacement mechanism to prepare a mixed solvent, 100 parts of amorphous polyester resin were slowly added to dissolve it, and a 10% aqueous ammonia solution (equivalent to 3 times the amount of the acid value of the resin in terms of molar ratio) was added thereto and stirred for 30 minutes. Next, the container was replaced with dry nitrogen, the temperature was maintained at 40°C, and 400 parts of ion exchange water were added dropwise to the mixed solution while stirring it for emulsification. After the addition was completed, the emulsion was returned to 25°C to obtain a resin particle dispersion in which resin particles with a volume average particle size of 210 nm were dispersed. Ion exchange water was added to the resin particle dispersion to adjust the solid content to 20%, thereby preparing an amorphous polyester resin dispersion (A1).

[0255] [Preparation of Crystalline Polyester Resin Dispersion (B1)]

[0256] Dimethyl sebacate: 97 parts

[0257] ·Sodium 5-sulfonate dimethyl isophthalate: 3 parts

[0258] Ethylene glycol: 100 parts

[0259] Dibutyltin oxide (catalyst): 0.3 parts

[0260] The above materials were added to a three-necked flask after heating and drying, and the air in the three-necked flask was replaced with nitrogen to form an inert atmosphere. The mixture was stirred and refluxed at 180°C for 5 hours by mechanical stirring. Then, the temperature was slowly raised to 240°C under reduced pressure and stirred for 2 hours. After the mixture became viscous, it was air-cooled to stop the reaction. In this way, a crystalline polyester resin with a weight average molecular weight of 9700 and a melting temperature of 84°C was obtained.

[0261] 90 parts of crystalline polyester resin, 1.8 parts of anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., NEOGENRK) and 210 parts of ion exchange water were mixed, heated to 100°C, dispersed using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA), and then dispersed for 1 hour using a pressure discharge type Gaulin homogenizer to obtain a resin particle dispersion in which resin particles having a volume average particle size of 205 nm were dispersed. Ion exchange water was added to the resin particle dispersion to adjust the solid content to 20%, thereby forming a crystalline polyester resin dispersion (B1).

[0262] [Preparation of Release Agent Particle Dispersion (W1)]

[0263] Solid paraffin wax (HNP-9 manufactured by Nippon Seira Co., Ltd.): 100 parts

[0264] Anionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1 part

[0265] Ion exchange water: 350 parts

[0266] The above materials were mixed and heated to 100°C, dispersed using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA), and then dispersed using a pressure-dispensing Gaulin homogenizer to obtain a release agent particle dispersion in which release agent particles having a volume average particle size of 200 nm were dispersed. Ion-exchanged water was added to the release agent particle dispersion to adjust the solid content to 20%, thereby forming a release agent particle dispersion (W1).

[0267] [Preparation of Colorant Particle Dispersion Liquid (K1)]

[0268] Carbon black (Regal 330 manufactured by Cabot Corporation): 50 parts

[0269] Ionic surfactant NEOGEN RK (Daiichi Kogyo Pharmaceutical): 5 parts

[0270] Ion exchange water: 195 parts

[0271] The above materials were mixed and dispersed at 240 MPa for 10 minutes using an Ultimaizer (manufactured by Sugino Machine Co., Ltd.) to obtain a colorant particle dispersion (K1) having a solid content of 20%.

[0272] [Preparation of Toner Particles]

[0273] Ion exchange water: 200 parts

[0274] Amorphous polyester resin dispersion (A1): 150 parts

[0275] Crystalline polyester resin dispersion (B1): 10 parts

[0276] Release agent particle dispersion (W1): 10 parts

[0277] Colorant particle dispersion (K1): 15 parts

[0278] Anionic surfactant (TaycaPower): 2.8 parts

[0279] The above materials were placed in a round stainless steel flask, 0.1N nitric acid was added to adjust the pH to 3.5, and then an aqueous solution of polyaluminum chloride was added by dissolving 2 parts of polyaluminum chloride (manufactured by Oji Paper Co., Ltd., 30% powder) in 30 parts of ion exchange water. After dispersion at 30°C using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA), it was heated to 45°C in a heating oil bath and maintained until the volume average particle size reached 4.9μm. Next, 60 parts of amorphous polyester resin dispersion (A1) were added and maintained for 30 minutes. Then, after the volume average particle size reached 5.2μm, 60 parts of amorphous polyester resin dispersion (A1) were further added and maintained for 30 minutes. Next, 20 parts of a 10% NTA (nitrilotriacetic acid) metal salt aqueous solution (Chelest 70, manufactured by Chelest Co., Ltd.) were added, and a 1N sodium hydroxide aqueous solution was added to adjust the pH to 9.0. Next, 1 part of anionic surfactant (Tayca Power) was added, and the mixture was heated to 85° C. and maintained for 5 hours while being stirred. Then, the mixture was cooled to 20° C. at a rate of 20° C. / min. Then, the mixture was filtered, washed thoroughly with ion exchange water, and dried to obtain toner particles (1) having a volume average particle size of 5.7 μm.

[0280] <Preparation of Toner Particles (2) to (5)>

[0281] By changing the holding time in the fusion / coalescing step, toner particles (2) to (5) having different volume average particle diameters are obtained in the same manner as in the production of the toner particles (1).

[0282] Toner particles (2): volume average particle size 13.0 μm

[0283] Toner particles (3): volume average particle size 2.8 μm

[0284] Toner particles (4): volume average particle size 9.8 μm

[0285] Toner particles (5): volume average particle size 3.0 μm

[0286] <Preparation of melamine cyanurate granules (1) to (11)>

[0287] The following melamine cyanurate granules (1) to (11) were prepared. "MC" in Table 1 means melamine cyanurate.

[0288] Melamine cyanurate particles (1): crystallite diameter The average particle size is 0.8 μm

[0289] Melamine cyanurate particles (2): crystallite diameter The average particle size is 0.9 μm

[0290] Melamine cyanurate particles (3): crystallite diameter The average particle size is 0.2 μm

[0291] Melamine cyanurate particles (4): crystallite diameter The average particle size is 2.4 μm

[0292] Melamine cyanurate particles (5): crystallite diameter The average particle size is 0.3 μm

[0293] Melamine cyanurate particles (6): crystallite diameter The average particle size is 2.5 μm

[0294] Melamine cyanurate particles (7): crystallite diameter The average particle size is 0.8 μm

[0295] Melamine cyanurate particles (8): crystallite diameter The average particle size is 0.3 μm

[0296] Melamine cyanurate particles (9): crystallite diameter The average particle size is 0.3 μm

[0297] Melamine cyanurate particles (10): crystallite diameter The average particle size is 1.9 μm

[0298] Melamine cyanurate particles (11): crystallite diameter The average particle size is 1.9 μm

[0299] <Preparation of carrier>

[0300] After 500 parts of spherical magnetite powder particles (volume average particle size 0.55 μm) were stirred with a Henschel mixer, 5 parts of a titanate coupling agent were added, the temperature was raised to 100°C, and the mixture was stirred for 30 minutes. Next, 6.25 parts of phenol, 9.25 parts of 35% formaldehyde, 500 parts of magnetite particles treated with a titanate coupling agent, 6.25 parts of 25% ammonia water, and 425 parts of water were added to a four-necked flask and stirred. The mixture was reacted at 85°C for 120 minutes under stirring, cooled to 25°C, 500 parts of water were added, the supernatant was removed, and the precipitate was washed with water. The washed precipitate was dried by heating under reduced pressure to obtain a carrier with an average particle size of 35 μm.

[0301] <Example 1>

[0302] 100 parts of toner particles (1), 1.6 parts of silica particles (RX200 manufactured by NIPPON AEROSIL Co., Ltd.) hydrophobized with hexamethyldisilazane, and melamine cyanurate particles (1) in an amount to achieve the content (mass %) described in Table 1 were added to a sample mill and mixed at 10000 rpm for 30 seconds. Then, the mixture was sieved with a vibrating sieve having a mesh size of 45 μm to prepare a toner having a volume average particle size of 5.7 μm.

[0303] The toner and the carrier were charged into a V-type blender at a ratio of toner:carrier=5:95 (mass ratio), and stirred for 20 minutes to obtain a developer.

[0304] <Examples 2 to 5, Comparative Examples 1 to 6>

[0305] A toner and a developer were obtained in the same manner as in Example 1 except that the type of toner particles or the type and amount of layered compound particles added were changed.

[0306] <Performance Evaluation>

[0307] A developer was loaded into a modified image forming apparatus (700 Digital Color Press) manufactured by Fuji Xerox Co., Ltd. and placed in a room at 10°C and 15% relative humidity for 1 day to adjust the temperature and humidity. 100,000 images with an image density of 30% were output on A4-sized paper at a temperature of 10°C and a relative humidity of 15%, and then 500 solid images and toner loading of 0.1 mg / cm were output on A4-sized paper. 2 The 10th, 50th, 100th, and 500th images were visually observed, and the total number of color fringes generated in the halftone images was ranked according to the following criteria.

[0308] G1: 0

[0309] G2: 1 to 5

[0310] G3: 6 to 10

[0311] G4: More than 11 items. This is not practically acceptable.

[0312] [Table 1]

[0313]

Claims

1. A toner for electrostatic image development, wherein: The toner contains toner particles and layered structure compound particles. The layered structure compound particles are melamine cyanurate particles. The crystallite diameter of the above-mentioned layered compound particles calculated from the maximum peak width of the CuKα-ray X-ray diffraction pattern is above and the number average particle size Dn of the layered structure compound particles is 0.3 μm or more and 2.0 μm or less, The ratio Dn / Dv of the number average particle diameter Dn of the layered structure compound particles to the volume average particle diameter Dv of the toner particles is 0.03 or more and 0.7 or less.

2. The electrostatic image developing toner according to claim 1, wherein The content of the layered structure compound particles is 0.1% by mass or more and 2.0% by mass or less based on the entire electrostatic image developing toner.

3. The electrostatic image developing toner according to claim 2, wherein The content of the layered structure compound particles is 0.1% by mass or more and 1.0% by mass or less based on the entire electrostatic image developing toner.

4. The electrostatic image developing toner according to any one of claims 1 to 3, wherein The crystallite diameter of the layered compound particles is above the following.

5. The electrostatic image developing toner according to any one of claims 1 to 3, wherein The number average particle size Dn of the layered structure compound particles is not less than 0.3 μm and not more than 1.8 μm.

6. The electrostatic image developing toner according to any one of claims 1 to 3, wherein The ratio Dn / Dv of the number average particle diameter Dn of the layered structure compound particles to the volume average particle diameter Dv of the toner particles is 0.05 or more and 0.6 or less.

7. The electrostatic image developing toner according to any one of claims 1 to 3, wherein The toner particles have a volume average particle diameter Dv of 3.0 μm or more and 10.0 μm or less.

8. The electrostatic image developing toner according to claim 7, wherein The toner particles have a volume average particle diameter Dv of 3.5 μm or more and 7.0 μm or less. 9 . An electrostatic image developer comprising the electrostatic image developing toner according to claim 1 . 10 . A toner cartridge that is detachably mounted in an image forming apparatus, the toner storing the electrostatic image developing toner according to claim 1 .

11. A process cartridge to be loaded and unloaded in an image forming apparatus, comprising: a developing mechanism storing the electrostatic image developer according to claim 9 and developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer; an intermediate transfer body to which the toner image formed on the surface of the image holding body is transferred; as well as The cleaning mechanism includes a scraper in contact with the surface of the intermediate transfer body, and uses the scraper to clean the toner remaining on the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium.

12. An image forming apparatus comprising: Image holding body; A charging mechanism for charging the surface of the image holding body; An electrostatic image forming mechanism for forming an electrostatic image on the charged surface of the image holding member; a developing mechanism storing the electrostatic image developer according to claim 9 and developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer; an intermediate transfer body to which the toner image formed on the surface of the image holding body is transferred; A primary transfer mechanism, transferring the toner image formed on the surface of the image holding body to the surface of the intermediate transfer body; A secondary transfer mechanism transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium; a fixing mechanism for fixing the toner image transferred to the surface of the recording medium; and The cleaning mechanism includes a scraper in contact with the surface of the intermediate transfer body, and uses the scraper to clean the toner remaining on the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium.

13. An image forming method comprising the following steps: A charging step of charging the surface of the image holding body; An electrostatic image forming step of forming an electrostatic image on the charged surface of the image holding member; a developing step of developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer according to claim 9; a primary transfer step of transferring the toner image formed on the surface of the image holding body to the surface of the intermediate transfer body; A secondary transfer step of transferring the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium; a fixing step of fixing the toner image transferred to the surface of the recording medium; and In the cleaning step, the scraper is brought into contact with the surface of the intermediate transfer body after the toner image is transferred to the surface of the recording medium, so as to clean the toner remaining on the surface of the intermediate transfer body.

Images