Electrostatic image developing toner, electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method

Abstract

The present invention relates to an electrostatic image developing toner, an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus and an image forming method. The electrostatic image developing toner comprises toner particles, layered structure compound particles and inorganic particles, wherein the average circularity of the inorganic particles is 0.910 or more and 0.995 or less, and the ratio Da / Db of the number average particle diameter Da of the layered structure compound particles to the number average particle diameter Db of the inorganic particles is 1.2 or more and 43 or less.

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 obtained 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 100 parts by weight of a base toner having an average circularity of 0.94 to 0.995 and a volume average particle size of 3 to 9 μm.

[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. Compared with a toner for electrostatic image development comprising toner particles, layered structure compound particles and inorganic particles, wherein the average roundness of the inorganic particles is less than 0.910 or the ratio Da / Db of the number average particle size Da of the layered structure compound particles to the number average particle size Db of the inorganic particles is less than 1.2 or greater than 43, the toner for electrostatic image development of the present invention can inhibit the generation of color stripes caused by agglomerates of layered structure compound particles.

[0006] Means for solving technical problems

[0007] According to a first aspect of the present invention, there is provided a toner for developing an electrostatic image, wherein:

[0008] The toner contains toner particles, layered structure compound particles and inorganic particles.

[0009] The average circularity of the inorganic particles is 0.910 or more and 0.995 or less, and the ratio Da / Db of the number average particle diameter Da of the layered structure compound particles to the number average particle diameter Db of the inorganic particles is 1.2 or more and 43 or less.

[0010] According to the second aspect of the present invention, the ratio Da / Db of the number average particle diameter Da of the layered structure compound particles to the number average particle diameter Db of the inorganic particles is 5 or more and 43 or less.

[0011] According to a third aspect of the present invention, a mass-based ratio Mb / Ma of the content Ma of the layered structure compound particles to the content Mb of the inorganic particles is 0.1 or more and 500 or less.

[0012] According to a fourth aspect of the present invention, a mass-based ratio Mb / Ma of the content Ma of the layered structure compound particles to the content Mb of the inorganic particles is 1 to 500.

[0013] According to a fifth aspect of the present invention, the content of the layered structure compound particles is 0.01% by mass or more and 5.0% by mass or less based on the entire electrostatic image developing toner.

[0014] According to a sixth aspect of the present invention, the content of the layered structure compound particles is 0.01% by mass or more and 0.5% by mass or less based on the entire electrostatic image developing toner.

[0015] According to a seventh aspect of the present invention, the layered structure compound particles have a number average particle size Da of 0.3 μm or more and 5.0 μm or less.

[0016] According to an eighth aspect of the present invention, the layered structure compound particles have a number average particle size Da of 0.4 μm or more and 2.0 μm or less.

[0017] According to a ninth aspect of the present invention, the inorganic particles have a number average particle size Db of 0.06 μm or more and 0.3 μm or less.

[0018] According to a tenth aspect of the present invention, the inorganic particles have a number average particle size Db of 0.07 μm or more and 0.2 μm or less.

[0019] According to an eleventh aspect of the present invention, the layered structure compound particles include at least one selected from the group consisting of melamine cyanurate particles, boron nitride particles, graphite fluoride particles, molybdenum disulfide particles, and mica particles.

[0020] According to a twelfth aspect of the present invention, the inorganic particles include silica particles.

[0021] According to a thirteenth aspect of the present invention, there is provided an electrostatic image developer comprising the above-mentioned electrostatic image developing toner.

[0022] According to a fourteenth 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.

[0023] According to the 15th scheme of the present invention, there is provided a processing box which is loaded and unloaded in an image forming device, and comprises: an image retaining body; a developing mechanism which stores the electrostatic image developer and develops the electrostatic image formed on the surface of the image retaining body into a toner image using the electrostatic image developer; and a cleaning mechanism which has a scraper in contact with the surface of the image retaining body and uses the scraper to clean the toner remaining on the surface of the image retaining body after the toner image is transferred.

[0024] According to the 16th scheme of the present invention, there is provided an image forming device, which comprises: an image retainer; a charging mechanism for charging the surface of the above-mentioned image retainer; an electrostatic image forming mechanism for forming an electrostatic image on the charged surface of the above-mentioned image retainer; a developing mechanism for storing the above-mentioned electrostatic image developer and developing the electrostatic image formed on the surface of the above-mentioned image retainer into a toner image using the above-mentioned electrostatic image developer; a transfer mechanism for transferring the toner image formed on the surface of the above-mentioned image retainer to the surface of a recording medium; a fixing mechanism for fixing the toner image transferred to the surface of the above-mentioned recording medium; and a cleaning mechanism having a scraper in contact with the surface of the above-mentioned image retainer, and using the above-mentioned scraper to clean the toner remaining on the surface of the above-mentioned image retainer after the toner image is transferred.

[0025] According to the 17th scheme of the present invention, an image forming method is provided, which has the following steps: a charging step of charging the surface of the image retainer; an electrostatic image forming step of forming an electrostatic image on the charged surface of the above-mentioned image retainer; a developing step of developing the electrostatic image formed on the surface of the above-mentioned image retainer into a toner image using the above-mentioned electrostatic image developer; a transfer step of transferring the toner image formed on the surface of the above-mentioned image retainer to the surface of the recording medium; a fixing step of fixing the toner image transferred to the surface of the above-mentioned recording medium; and a cleaning step of bringing a scraper into contact with the surface of the above-mentioned image retainer after the toner image is transferred, so as to clean the toner remaining on the surface of the above-mentioned image retainer.

[0026] Effects of the Invention

[0027] According to the above-mentioned schemes 1, 11 or 12, a toner for electrostatic image development is provided. Compared with a toner for electrostatic image development comprising toner particles, layered structure compound particles and inorganic particles, wherein the average roundness of the inorganic particles is less than 0.910 or the ratio Da / Db of the number average particle size Da of the layered structure compound particles to the number average particle size Db of the inorganic particles is less than 1.2 or greater than 43, the provided scheme can suppress the generation of color stripes caused by agglomerates of the layered structure compound particles.

[0028] According to the above-mentioned second scheme, a colorant for electrostatic image development is provided. Compared with a colorant for electrostatic image development in which the ratio Da / Db of the number average particle size Da of layered structure compound particles to the number average particle size Db of inorganic particles is less than 5 or greater than 43, the scheme provided can suppress the generation of color stripes caused by agglomerates of layered structure compound particles.

[0029] According to the above-mentioned third scheme, a toner for electrostatic image development is provided. Compared with a toner for electrostatic image development in which the mass basis ratio Mb / Ma of the content Ma of layered structure compound particles to the content Mb of inorganic particles is less than 0.1 or greater than 500, the scheme provided can suppress the generation of color stripes caused by agglomerates of layered structure compound particles.

[0030] According to the above-mentioned fourth scheme, a colorant for electrostatic image development is provided. Compared with a colorant for electrostatic image development in which the mass basis ratio Mb / Ma of the content Ma of layered structure compound particles to the content Mb of inorganic particles is less than 1 or greater than 500, the scheme provided can suppress the generation of color stripes caused by agglomerates of layered structure compound particles.

[0031] According to the above-mentioned scheme 5, a toner for electrostatic image development is provided, which can suppress the generation of color stripes caused by agglomerates of layered structure compound particles, compared with a toner for electrostatic image development in which the content of layered structure compound particles is less than 0.01 mass % or greater than 5 mass % relative to the entire electrostatic charge developing toner.

[0032] According to the above-mentioned scheme 6, a toner for electrostatic image development is provided, which can suppress the generation of color stripes caused by agglomerates of layered structure compound particles, compared with an electrostatic image developing toner in which the content of layered structure compound particles is less than 0.01 mass % or greater than 0.5 mass % relative to the entire electrostatic image developing toner.

[0033] According to the above-mentioned scheme 7, a toner for electrostatic image development is provided. Compared with the toner for electrostatic image development in which the number average particle size Da of layered structure compound particles is less than 0.3μm or greater than 5.0μm, the scheme provided can suppress the generation of color stripes caused by agglomerates of layered structure compound particles.

[0034] According to the above-mentioned scheme 8, a toner for electrostatic image development is provided, which can suppress the generation of color stripes caused by agglomerates of layered structure compound particles, compared with the toner for electrostatic image development in which the number average particle size Da of layered structure compound particles is less than 0.4μm or greater than 2.0μm.

[0035] According to the above-mentioned scheme 9, a toner for electrostatic image development is provided. Compared with the toner for electrostatic image development in which the number average particle size Db of inorganic particles is less than 0.06μm or greater than 0.3μm, the scheme provided can suppress the generation of color stripes caused by agglomerates of layered structure compound particles.

[0036] According to the above-mentioned scheme 10, a toner for electrostatic image development is provided, which can suppress the generation of color stripes caused by agglomerates of layered structure compound particles compared to the toner for electrostatic image development in which the number average particle size Db of inorganic particles is less than 0.07μm or greater than 0.2μm.

[0037] According to the above-mentioned scheme 13, an electrostatic image developer is provided, which can suppress the generation of color stripes caused by agglomerates of layered structure compound particles, compared with the case where the electrostatic image developing toner contains toner particles, layered structure compound particles and inorganic particles, and the average roundness of the inorganic particles is less than 0.910 or the ratio Da / Db of the number average particle size Da of the layered structure compound particles to the number average particle size Db of the inorganic particles is less than 1.2 or greater than 43.

[0038] According to the above-mentioned 14th scheme, a toner box is provided, which can suppress the generation of color stripes caused by agglomerates of layered structure compound particles, compared with the case where the toner for electrostatic image development contains toner particles, layered structure compound particles and inorganic particles, and the average roundness of the inorganic particles is less than 0.910 or the ratio Da / Db of the number average particle size Da of the layered structure compound particles to the number average particle size Db of the inorganic particles is less than 1.2 or greater than 43.

[0039] According to the above-mentioned scheme 15, a processing box is provided, which can suppress the generation of color stripes caused by agglomerates of layered structure compound particles, compared with the case where the toner for electrostatic image development contains toner particles, layered structure compound particles and inorganic particles, and the average roundness of the inorganic particles is less than 0.910 or the ratio Da / Db of the number average particle size Da of the layered structure compound particles to the number average particle size Db of the inorganic particles is less than 1.2 or greater than 43.

[0040] According to the above-mentioned 16th scheme, an image forming device is provided, which can suppress the generation of color stripes caused by agglomerates of layered structure compound particles, compared with the case where the electrostatic image developing toner contains toner particles, layered structure compound particles and inorganic particles, and the average roundness of the inorganic particles is less than 0.910 or the ratio Da / Db of the number average particle size Da of the layered structure compound particles to the number average particle size Db of the inorganic particles is less than 1.2 or greater than 43.

[0041] According to the above-mentioned 17th scheme, an image forming method is provided, which can suppress the generation of color stripes caused by agglomerates of layered structure compound particles, compared with the case where the electrostatic image developing toner contains toner particles, layered structure compound particles and inorganic particles, and the average roundness of the inorganic particles is less than 0.910 or the ratio Da / Db of the number average particle size Da of the layered structure compound particles to the number average particle size Db of the inorganic particles is less than 1.2 or greater than 43. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic structural diagram showing an example of the image forming apparatus according to the present embodiment.

[0043] 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

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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”.

[0052] <Toner for Electrostatic Image Development>

[0053] The toner of this embodiment includes toner particles, layered compound particles and inorganic particles, the average circularity of the inorganic particles is 0.910 to 0.995, and the ratio Da / Db of the number average particle size Da of the layered compound particles to the number average particle size Db of the inorganic particles is 1.2 to 43.

[0054] The toner of the present embodiment can suppress the occurrence of color streaks caused by aggregates of layered structure compound particles. The mechanism is presumed to be as follows.

[0055] 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 mutual slipping between the layers. The compound particles of the layered structure added to the toner act as a lubricant at the contact portion between the image holder and the cleaning blade.

[0056] However, in a situation where the cleaning blade is excessively introduced into the rotation direction of the image holder, for example, in a situation where high-density image formation is continuously performed for a long time in a high-temperature and high-humidity environment (for example, a temperature of 28° C. and a relative humidity of 85%), the force applied to the front end of the cleaning blade increases, so that the interlayer space of the layered structure compound particles is compressed, and the layered structure compound particles are compressed against each other to form agglomerates. Furthermore, the agglomerates of the layered structure compound particles sometimes leak out of the cleaning blade, causing color stripes in the image.

[0057] In order to address the above-mentioned problems, in this embodiment, when the size of the inorganic particles added to the toner together with the layered structure compound particles is within an appropriate range, that is, when the ratio Da / Db of the number average particle size Da of the layered structure compound particles to the number average particle size Db of the inorganic particles is greater than 1.2 and less than 43, it is speculated that the inorganic particles will enter between the layered structure compound particles and inhibit the agglomeration of the layered structure compound particles.

[0058] In addition, when the average roundness of the inorganic particles is 0.910 or more (i.e., when the roundness is high, the spherical inorganic particles), the inorganic particles entering between the layered structure compound particles play a roller role, improving the lubricity of the layered structure compound particles, so it can be inferred that even in the case of long-term continuous imaging of high-density images under high temperature and high humidity, the lubrication of the layered structure compound particles is not easily lost. It can also be inferred that by making the inorganic particles play a roller role, the aggregation of the layered structure compound particles can be suppressed.

[0059] Therefore, it is estimated that when the toner of this embodiment is used, aggregates of the layered compound particles are less likely to form at the contact portion between the image holder and the cleaning blade, the lubricating effect of the layered compound particles is sustained, and the occurrence of color streaks can be suppressed.

[0060] In the toner of this embodiment, from the viewpoint of suppressing aggregation of the layered compound particles, the ratio Da / Db of the number average particle diameter Da of the layered compound particles to the number average particle diameter Db of the inorganic particles is 1.2 to 43.

[0061] When the ratio Da / Db is less than 1.2, the inorganic particles are too large relative to the layered compound particles, and it is presumed that the inorganic particles are less likely to enter between the layered compound particles.

[0062] When the ratio Da / Db is greater than 43, the inorganic particles are too small relative to the layered compound particles, and it is presumed that the inorganic particles are buried in the surface of the layered compound particles and cannot function as rollers.

[0063] From the above viewpoints, the ratio Da / Db is 1.2 to 43, more preferably 5 to 43, and even more preferably 10 to 43.

[0064] In the toner of this embodiment, the average circularity of the inorganic particles added to the toner together with the layered structure compound particles is 0.910 or more, from the perspective of exerting a roller function between the layered structure compound particles. When the average circularity of the inorganic particles is less than 0.910, that is, when the inorganic particles are irregular inorganic particles with low circularity, the roller function is poor. The average circularity of the inorganic particles is preferably 0.920 or more, more preferably 0.930 or more, and further preferably 0.940 or more.

[0065] From the perspective of the expected rolling effect of the inorganic particles, the higher the average roundness of the inorganic particles, the better. However, it is not easy to make the inorganic particles as a whole a perfect sphere (ie, the average roundness is 1). Therefore, it is realistic for the average roundness of the inorganic particles to be 0.995 or less.

[0066] From the perspective of more effectively exerting the above-mentioned mechanism and suppressing the aggregation of the layered structure compound particles, the mass basis ratio Mb / Ma of the content Ma of the layered structure compound particles to the content Mb of the inorganic particles is preferably greater than 0.1 and less than 500, more preferably greater than 1 and less than 500, and further preferably greater than 5 and less than 500.

[0067] The components, structure, and characteristics of the toner according to this embodiment are described in detail below.

[0068] [Toner particles]

[0069] The toner particles contain, for example, a binder resin and, if necessary, a colorant, a release agent, and other additives.

[0070] - Adhesive resin -

[0071] Examples of the adhesive resin include vinyl resins formed by homopolymers of the following monomers or copolymers of two or more of these monomers: styrenes (e.g., styrene, p-chlorostyrene, α-methylstyrene, etc.), (meth)acrylates (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (e.g., ethylene, propylene, butadiene, etc.), and the like.

[0072] 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.

[0073] These adhesive resins may be used alone or in combination of two or more.

[0074] As the adhesive resin, a polyester resin is suitable.

[0075] 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.

[0076] 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).

[0077] 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.

[0078] Amorphous polyester resin

[0079] 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.

[0080] 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.

[0081] 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.

[0082] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0083] 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.

[0084] 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.

[0085] The polyols may be used alone or in combination of two or more.

[0086] 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.

[0087] 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".

[0088] 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.

[0089] The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2,000 or more and 100,000 or less.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] Crystalline polyester resin

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0101] 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-eicosandiolus. Among these, preferred aliphatic diols include 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol.

[0102] 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.

[0103] The polyols may be used alone or in combination of two or more.

[0104] Here, the content of the aliphatic diol in the polyol is preferably 80 mol % or more, and preferably 90 mol % or more.

[0105] 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.

[0106] 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 the melting temperature in JIS K7121:1987 “Methods for measuring transition temperatures of plastics”.

[0107] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

[0108] The crystalline polyester resin can be obtained, for example, by a known production method similar to the amorphous polyester.

[0109] 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.

[0110] -Colorants-

[0111] 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.

[0112] The coloring agent may be used alone or in combination of two or more.

[0113] 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.

[0114] 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.

[0115] -Release agent-

[0116] 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.

[0117] The melting temperature of the release agent is preferably 50°C to 110°C, more preferably 60°C to 100°C.

[0118] 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 the melting temperature in JIS K7121:1987 “Methods for measuring transition temperatures of plastics”.

[0119] 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.

[0120] -Other additives-

[0121] 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.

[0122] -Characteristics of toner particles, etc.-

[0123] 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.

[0124] Here, the toner particles of the 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.

[0125] The volume average particle diameter (D50v) of the toner particles is preferably from 2 μm to 10 μm, and more preferably from 4 μm to 8 μm.

[0126] The various average particle diameters and various particle size distribution indices of the toner particles are measured using Coulter Multisizer II (manufactured by Beckman Coulter) and ISOTON-II (manufactured by Beckman Coulter) for the electrolyte.

[0127] In the measurement, 0.5 mg to 50 mg of the measurement sample is added to 2 ml of a 5 mass % aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate) as a dispersant, and then added to 100 ml to 150 ml of the electrolyte.

[0128] The electrolyte in which the sample was suspended was dispersed by an ultrasonic disperser for 1 minute, and the particle size distribution of particles with a particle size ranging from 2 μm to 60 μm was measured by Coulter Multisizer II using an aperture of 100 μm. The number of particles sampled was 50,000.

[0129] Relative to the particle size range (segments) divided based on the measured particle size distribution, the volume and number are plotted as cumulative distributions from the smaller diameter side, the particle size at the cumulative 16% point is defined as the volume particle size D16v and the number particle size D16p, the particle size at the cumulative 50% point is defined as the volume average particle size D50v and the cumulative number average particle size D50p, and the particle size at the cumulative 84% point is defined as the volume particle size D84v and the number particle size D84p.

[0130] Using these values, the volume particle size distribution index (GSDv) is calculated as (D84v / D16v) 1 / 2 Calculate and convert the particle size distribution index (GSDp) into (D84p / D16p) 1 / 2 Calculated.

[0131] The average circularity of the toner particles is preferably from 0.94 to 1.00, and more preferably from 0.95 to 0.98.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] [Layered compound particles]

[0136] 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.

[0137] From the perspective of suppressing the aggregation of the layered structure compound particles, the number average particle size Da of the layered structure compound particles is preferably 0.3 μm to 5.0 μm, more preferably 0.3 μm to 4.0 μm, further preferably 0.4 μm to 3.0 μm, and further preferably 0.4 μm to 2.0 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.

[0138] The number average particle size Da of the layered structure compound particles is determined by the following measurement method.

[0139] 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 the inorganic particles according to their specific gravity. The fraction containing the layered structure compound particles is extracted and dried to obtain the layered structure compound particles.

[0140] 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 Da.

[0141] From the perspective of obtaining the lubricating effect of the layered structure compound particles, the content of the layered structure compound particles is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, further preferably 0.05% by mass or more, and further preferably 0.1% by mass or more relative to the entire toner. From the perspective of suppressing the aggregation of the layered structure compound particles, the content of the layered structure compound particles is preferably 5.0% by mass or less, more preferably 1.0% by mass or less, further preferably 0.7% by mass or less, and further preferably 0.5% by mass or less relative to the entire toner.

[0142] [Inorganic particles]

[0143] As inorganic particles, there can be mentioned SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, etc.

[0144] As inorganic particles, silica particles are preferred from the aspect of high roundness, and sol-gel silica particles are more preferred. The sol-gel method for producing sol-gel silica particles is well known. The sol-gel method includes, for example: adding aqueous ammonia to a mixed solution obtained by mixing tetraalkoxysilane, water and alcohol to prepare a silica sol suspension; centrifugally separating wet silica gel from the silica sol suspension; and drying the wet silica gel to obtain silica particles. Examples of tetraalkoxysilanes include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane and the like.

[0145] The surface of inorganic particles is suitably subjected to hydrophobization treatment. Hydrophobization treatment is carried out by, for example, immersing inorganic particles in hydrophobization treatment agents. There is no particular limitation on the hydrophobization treatment agent, 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.

[0146] From the perspective of suppressing the aggregation of the layered structure compound particles, the average circularity of the inorganic particles is 0.910 or more, preferably 0.920 or more, more preferably 0.930 or more, and further preferably 0.940 or more. From the perspective of ease of circularity adjustment, the average circularity of the inorganic particles is 0.995 or less.

[0147] From the viewpoint of suppressing aggregation of the layered structure compound particles, the number average particle size Db of the inorganic particles is preferably 0.06 μm to 0.3 μm, more preferably 0.06 μm to 0.25 μm, and even more preferably 0.07 μm to 0.2 μm.

[0148] The average circularity and number average particle size Db of the inorganic particles are determined by the following measuring methods.

[0149] First, inorganic particles are separated from the toner. There is no limitation on the method for separating inorganic 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 the inorganic particles according to their specific gravity. The fraction containing the inorganic particles is extracted and dried to obtain the inorganic particles.

[0150] Next, the inorganic particles were photographed using a scanning electron microscope (SEM), and the circularity of each of 1000 randomly selected primary particles was determined by image analysis (=4π×(area of ​​particle image)÷(circumference of particle image) 2 ) and equivalent circle diameter (μm).

[0151] The average circularity is the circularity of 50% of the points accumulated from the small circularity side in the circularity distribution based on the number.

[0152] The number average particle diameter Db is an equivalent circle diameter at which 50% of points are accumulated from the smaller diameter side in the distribution of equivalent circle diameters based on number.

[0153] From the perspective of suppressing aggregation of the layered structure compound particles, the content of the inorganic particles is preferably 0.3 mass % to 5.0 mass %, more preferably 0.5 mass % to 3.0 mass %, and even more preferably 0.5 mass % to 2.5 mass %, relative to the entire toner.

[0154] [Other additives]

[0155] The toner of this embodiment may contain other external additives in addition to the layered structure compound particles and the inorganic particles. Examples of other external additives include resin particles (resin particles such as polystyrene, polymethyl methacrylate, and melamine resin), detergent activators (such as metal salts of higher fatty acids represented by zinc stearate, and particles of fluorine-based high molecular weight bodies).

[0156] When the toner of this embodiment contains other external additives in addition to the layered structure compound particles and the inorganic particles, the total amount of other external additives added is preferably 0.01 mass % to 5.0 mass %, more preferably 0.01 mass % to 2.0 mass %, relative to the toner particles.

[0157] [Toner Manufacturing Method]

[0158] The toner according to the present embodiment is obtained by manufacturing toner particles and then adding an external additive to the toner particles.

[0159] 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 (aggregation and unification) methods, suspension polymerization methods, and dissolution and suspension methods). 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.

[0160] 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 (fusion·unification) step).

[0161] The details of each step are described below.

[0162] 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.

[0163] - Resin particle dispersion preparation step -

[0164] 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.

[0165] The resin particle dispersion is prepared, for example, by dispersing the resin particles in a dispersion medium using a surfactant.

[0166] Examples of the dispersion medium used for the resin particle dispersion include aqueous media.

[0167] 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.

[0168] 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.

[0169] The surfactant may be used alone or in combination of two or more.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] - Agglomerated Particle Formation Step-

[0176] Next, the resin particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mixed.

[0177] 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.

[0178] 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.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] - Fusion / Merge Steps-

[0186] 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.

[0187] Through the above steps, toner particles are obtained.

[0188] 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.

[0189] After the fusion / merging step is completed, the toner particles formed in the solution 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.

[0190] 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.

[0191] <Electrostatic Image Developer>

[0192] The electrostatic image developer according to the present embodiment includes at least the toner according to the present embodiment.

[0193] 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.

[0194] 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.

[0195] Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt; and magnetic oxides such as ferrite and magnetite.

[0196] 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.

[0197] 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.

[0198] 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.

[0199] 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.

[0200] <Image Forming Apparatus, Image Forming Method>

[0201] The image forming device of this 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 charged surface of the 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; a transfer mechanism for transferring the toner image formed on the surface of the image holder 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 image holder, and using the scraper to clean the toner remaining on the surface of the image holder after the toner image is transferred.

[0202] An image forming method (image forming method of the present embodiment) is implemented using the image forming device of the present embodiment, and the method 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, developing the electrostatic image formed on the surface of the image retaining body into a toner image using the electrostatic image developer of the present embodiment; a transfer step, transferring the toner image formed on the surface of the image retaining 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 a scraper into contact with the surface of the image retaining body after the toner image is transferred, and cleaning the toner remaining on the surface of the image retaining body.

[0203] The image forming device of this embodiment can be applied to the following well-known image forming devices: a device using a direct transfer method for directly transferring a toner image formed on the surface of an image holder to a recording medium; a device using an intermediate transfer method for transferring a toner image formed on the surface of an image holder to the surface of an intermediate transfer body for the first time, and transferring the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium for a second time; a device having a static elimination mechanism for eliminating static by irradiating the surface of an image holder with a static elimination light after the transfer of the toner image and before charging; and the like.

[0204] When the image forming device of the present embodiment is an intermediate transfer type device, the transfer mechanism used is, for example, a structure having the following components: an intermediate transfer body to the surface of which the toner image is transferred; a primary transfer mechanism that transfers the toner image formed on the surface of the image retaining body to the surface of the intermediate transfer body for the first time; and a secondary transfer mechanism that transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium for the second time.

[0205] 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.

[0206] 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.

[0207] Figure 1 2 is a diagram schematically showing the structure of the image forming apparatus according to the present embodiment.

[0208] 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.

[0209] 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 30 is provided on the image holding body side of the intermediate transfer belt 20 so as to face the driving roller 22.

[0210] 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.

[0211] 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.

[0212] 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.

[0213] 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, and removes the toner remaining on the surface of the photoreceptor 1Y.

[0214] 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).

[0215] Next, the operation of forming a yellow image in the first unit 10Y will be described.

[0216] 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.

[0217] 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.

[0218] 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.

[0219] 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.

[0220] 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.

[0221] 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.

[0222] The photoreceptor 1Y to which the toner image has been transferred 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.

[0223] 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.

[0224] 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.

[0225] 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 (an example of the secondary transfer mechanism) 26 arranged on the image holding surface side of the intermediate transfer belt 20. On the other hand, the recording paper (an example of the recording medium) P is fed to the gap between the secondary transfer roller 26 and the intermediate transfer belt 20 by the feeding member at a preset timing, 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.

[0226] Thereafter, the recording paper P is fed into 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 on the recording paper P to form a fixed image.

[0227] 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.

[0228] 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.

[0229] 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.

[0230] <Process Cartridge, Toner Cartridge>

[0231] The processing box of this embodiment is a processing box that is loaded and unloaded in an image forming device, and comprises: an image retaining body; a developing mechanism that stores the electrostatic image developer of this 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; and a cleaning mechanism that has a scraper that contacts the surface of the image retaining body, and uses the scraper to clean the toner remaining on the surface of the image retaining body after the toner image is transferred.

[0232] The process cartridge of the present embodiment is not limited to the above-described configuration, and may be configured to further include at least one selected from a charging mechanism, an electrostatic image forming mechanism, a transfer mechanism, and the like, for example.

[0233] 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.

[0234] Figure 2 1 is a schematic diagram showing the structure of the process cartridge according to the present embodiment.

[0235] Figure 2 The process cartridge 200 shown is configured by integrally holding 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 a cleaning mechanism) by a housing 117 having a mounting guide 116 and an opening 118 for exposure, and forming an ink cartridge. The photoreceptor cleaning device 113 has a scraper that contacts the photoreceptor 107.

[0236] Figure 2 109 denotes an exposure device (an example of an electrostatic image forming mechanism), 112 denotes a transfer device (an example of a transfer mechanism), 115 denotes a fixing device (an example of a fixing mechanism), and 300 denotes recording paper (an example of a recording medium).

[0237] Next, the toner cartridge according to the present embodiment will be described.

[0238] 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.

[0239] 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. In addition, when the toner stored in the toner cartridge is insufficient, the toner cartridge is replaced.

[0240] [Example]

[0241] The embodiments of the present invention are described in detail below by way of examples, but the embodiments of the present invention are not limited to these examples. In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0242] <Production of Toner Particles>

[0243] [Preparation of amorphous polyester resin dispersion (A1)]

[0244] Terephthalic acid: 70 parts

[0245] Fumaric acid: 30 parts

[0246] Ethylene glycol: 44 parts

[0247] 1,5-Pentanediol: 46 parts

[0248] 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.

[0249] 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).

[0250] [Preparation of Crystalline Polyester Resin Dispersion (B1)]

[0251]

[0252] 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.

[0253] 90 parts of crystalline polyester resin, 1.8 parts of anionic surfactant (NEOGEN RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 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).

[0254] [Preparation of Release Agent Particle Dispersion (W1)]

[0255] Solid paraffin wax (HNP-9 manufactured by Nippon Seira Co., Ltd.): 100 parts

[0256] Anionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1 part

[0257] Ion exchange water: 350 parts

[0258] 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).

[0259] [Preparation of Colorant Particle Dispersion Liquid (K1)]

[0260] Carbon black (Regal 330 manufactured by Cabot Corporation): 50 parts

[0261] Ionic surfactant NEOGEN RK (Daiichi Kogyo Pharmaceutical): 5 parts

[0262] Ion exchange water: 195 parts

[0263] 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%.

[0264] [Preparation of Toner Particles]

[0265]

[0266] The above materials are placed in a round stainless steel flask, 0.1N nitric acid is added to adjust the pH to 3.5, and then an aqueous solution of polyaluminum chloride obtained by dissolving 2 parts of polyaluminum chloride (manufactured by Oji Paper (Co., Ltd.), 30% powder) in 30 parts of ion exchange water is added. After dispersion at 30°C using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA), it is heated to 45°C in a heating oil bath and maintained until the volume average particle size reaches 4.9μm. Next, 60 parts of amorphous polyester resin dispersion (A1) are added and maintained for 30 minutes. Then, after the volume average particle size reaches 5.2μm, 60 parts of amorphous polyester resin dispersion (A1) are 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.) are added, and a 1N sodium hydroxide aqueous solution is 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 and an average circularity of 0.971.

[0267] <Production of Layered Compound Particles>

[0268] [Production of melamine cyanurate granules]

[0269] Commercially available melamine cyanurate particles were pulverized with a jet mill and classified to obtain the following melamine cyanurate particles (1) to (11). "MC" in Table 1 means melamine cyanurate.

[0270] Melamine cyanurate particles (1): average particle size 0.70 μm

[0271] Melamine cyanurate particles (2): average particle size 0.32 μm

[0272] Melamine cyanurate particles (3): average particle size 0.35 μm

[0273] Melamine cyanurate particles (4): average particle size 0.40 μm

[0274] Melamine cyanurate particles (5): average particle size 1.50 μm

[0275] Melamine cyanurate particles (6): average particle size 1.80 μm

[0276] Melamine cyanurate particles (7): average particle size 2.10 μm

[0277] Melamine cyanurate particles (8): average particle size 2.50 μm

[0278] Melamine cyanurate particles (9): average particle size 2.80 μm

[0279] Melamine cyanurate particles (10): number average particle size 3.00 μm

[0280] Melamine cyanurate particles (11): average particle size 3.50 μm

[0281] [Production of Boron Nitride Particles]

[0282] Commercially available boron nitride particles were pulverized with a jet mill and classified to obtain boron nitride particles having a number average particle size of 0.70 μm. “BN” in Table 1 refers to boron nitride.

[0283] [Preparation of Molybdenum Disulfide Particles]

[0284] Commercially available molybdenum disulfide particles were pulverized and classified using a jet mill to obtain molybdenum disulfide particles having a number average particle size of 0.70 μm. “MоS2” in Table 1 refers to molybdenum disulfide.

[0285] <Production of Silica Particles>

[0286] Silica particles were prepared by a sol-gel method, subjected to a hydrophobic treatment with hexamethyldisilazane, and classified as necessary to obtain the following silica particles.

[0287] Silica particles (1): number average particle size 0.09 μm, average roundness 0.950

[0288] Silica particles (2): number average particle size 0.09 μm, average roundness 0.920

[0289] Silica particles (3): number average particle size 0.09 μm, average roundness 0.980

[0290] Silica particles (4): number average particle size 0.06 μm, average roundness 0.950

[0291] Silica particles (5): number average particle size 0.29 μm, average roundness 0.950

[0292] Silica particles (6): number average particle size 0.09 μm, average roundness 0.890

[0293] Silica particles (7): number average particle size 0.30 μm, average roundness 0.950

[0294] Silica particles (8): number average particle size 0.20 μm, average roundness 0.950

[0295] Silica particles (9): number average particle size 0.07 μm, average roundness 0.950

[0296] Silica particles (10): number average particle size 0.19 μm, average roundness 0.950

[0297] Silica particles (11): number average particle size 0.45 μm, average roundness 0.950

[0298] Silica particles (12): number average particle size 0.23 μm, average roundness 0.950

[0299] Silica particles (13): number average particle size 0.27 μm, average roundness 0.950

[0300] <Preparation of carrier>

[0301] 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.

[0302] <Example 1>

[0303] Toner particles (1), melamine cyanurate particles (1) and silica particles (1) were added to a sample mill at the proportions shown in Table 1 and mixed at 10,000 rpm for 30 seconds. The mixture was then sieved using a vibrating sieve with a mesh size of 45 μm to prepare a toner having a volume average particle size of 5.7 μm.

[0304] 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.

[0305] <Examples 2 to 19, Comparative Examples 1 to 3>

[0306] A toner and a developer were obtained in the same manner as in Example 1 except that the type and amount of the layered structure compound particles and the type and amount of the silica particles were changed.

[0307] <Performance Evaluation>

[0308] [Color streaks produced in high temperature and high humidity environments]

[0309] Using a modified 700 Digital Color Press manufactured by Fuji Xerox Co., Ltd., 100,000 images with an image density of 40% were output on A4-sized paper at a temperature of 28°C and a relative humidity of 85%, and then 500 halftone adjustment surface image charts were output on A4-sized paper. The 10th, 50th, 100th, and 500th of the 500 halftone images were visually observed, and the total number of color fringes generated in the images was ranked according to the following criteria.

[0310] G1: 0

[0311] G2: 1

[0312] G3: 2 to 5. Permissible range.

[0313] G4: More than 6. This is not practically acceptable.

[0314] [Cleaning the agglomerate in the box]

[0315] After the image formation, the contents of the cleaning box for the photoreceptor were taken out, sieved with a sieve having a mesh size of 45 μm, and the number of aggregates was counted.

[0316] G1: No agglutination

[0317] G2: 1 to 5 aggregates

[0318] G3: 6 to 19 aggregates

[0319] G4: 20 or more aggregates

[0320] [Table 1]

[0321]

Claims

1. A toner for electrostatic image development, wherein: The toner comprises toner particles, melamine cyanurate particles and inorganic particles. The average circularity of the inorganic particles is 0.910 or more and 0.995 or less. The ratio Da / Db of the number average particle size Da of the melamine cyanurate particles to the number average particle size Db of the inorganic particles is 1.2 to 43.

2. The electrostatic image developing toner according to claim 1, wherein The ratio Da / Db of the number average particle size Da of the melamine cyanurate particles to the number average particle size Db of the inorganic particles is 5 or more and 43 or less.

3. The electrostatic image developing toner according to claim 1 or 2, wherein The mass ratio Mb / Ma of the content Mb of the inorganic particles to the content Ma of the melamine cyanurate particles is 0.1 or more and 500 or less.

4. The electrostatic image developing toner according to claim 3, wherein The mass ratio Mb / Ma of the content Mb of the inorganic particles to the content Ma of the melamine cyanurate particles is 1 or more and 500 or less.

5. The electrostatic image developing toner according to claim 1 or 2, wherein The content of the melamine cyanurate particles is 0.01% by mass or more and 5.0% by mass or less based on the entire electrostatic image developing toner.

6. The electrostatic image developing toner according to claim 5, wherein The content of the melamine cyanurate particles is 0.01% by mass or more and 0.5% by mass or less based on the entire electrostatic image developing toner.

7. The electrostatic image developing toner according to claim 1 or 2, wherein The number average particle size Da of the melamine cyanurate particles is 0.3 μm or more and 5.0 μm or less.

8. The electrostatic image developing toner according to claim 7, wherein The number average particle size Da of the melamine cyanurate particles is 0.4 μm or more and 2.0 μm or less.

9. The electrostatic image developing toner according to claim 1 or 2, wherein The inorganic particles have a number average particle size Db of 0.06 μm or more and 0.3 μm or less.

10. The electrostatic image developing toner according to claim 9, wherein The inorganic particles have a number average particle size Db of 0.07 μm or more and 0.2 μm or less.

11. The electrostatic image developing toner according to claim 1 or 2, wherein The inorganic particles include silica particles. 12 . An electrostatic image developer comprising the electrostatic image developing toner according to claim 1 . 13 . A toner cartridge that is detachably mounted in an image forming apparatus, the toner storing the electrostatic image developing toner according to claim 1 .

14. A process cartridge to be loaded and unloaded in an image forming apparatus, comprising: Image holding body; a developing mechanism storing the electrostatic image developer according to claim 12 and developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer; and The cleaning mechanism includes a scraper in contact with the surface of the image holding member, and uses the scraper to clean the toner remaining on the surface of the image holding member after the toner image is transferred.

15. 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 12 and developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer; A transfer mechanism for transferring the toner image formed on the surface of the image holding 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 image holding member, and uses the scraper to clean the toner remaining on the surface of the image holding member after the toner image is transferred.

16. 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 12; a transfer step of transferring the toner image formed on the surface of the image holding 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, a scraper is brought into contact with the surface of the image holding member after the toner image is transferred, so as to clean the toner remaining on the surface of the image holding member.

Images