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 includes toner particles, layered structure compound particles, and free oil, and the mass-based ratio Ma / Mb of the content Ma of the layered structure compound particles to the content Mb of the free oil is 0.05 or more and 100 or less.

Description

Technical Field

[0001] The present invention relates to a toner for electrostatic image development, an electrostatic image developer, a toner cartridge, a processing cartridge, an image forming apparatus, and 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 diameter of 3 μm to 9 μm to 100 parts by weight of a mother toner having an average roundness of 0.94 to 0.995 and a volume average particle diameter of 3 μm to 9 μm.

[0003] Japanese Patent Application Laid-Open No. 2009-237274 discloses a positively charged toner obtained by adding 0.01 to 0.5 parts by weight of melamine cyanurate particles having an average primary particle diameter of 0.05 μm to 1.5 μm to 100 parts by weight of colored resin particles containing a binder resin, a colorant, and a positive charge control agent. 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 which can suppress the generation of color stripes caused by wear of the cleaning blade of the image holding member during continuous imaging in a high temperature and high humidity environment, and can suppress the generation of color stripes caused by leakage of the toner from the contact portion between the image holding member and the cleaning blade during continuous imaging in a low temperature and low humidity environment, as compared with a toner for electrostatic image development containing toner particles, layered structure compound particles, and free oil, and having a mass ratio Ma / Mb of the content Ma of the layered structure compound particles to the content Mb of the free oil less than 0.05 or greater than 100.

[0006] Means for Solving the Technical Problem

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

[0008] the toner contains toner particles, layered structure compound particles, and free oil,

[0009] a mass ratio Ma / Mb of the content Ma of the layered structure compound particles to the content Mb of the free oil is 0.05 or more and 100 or less.

[0010] According to the second aspect of the present invention, the content of the free oil is 0.005% by mass or more and 0.2% by mass or less with respect to the entire electrophotographic developer toner.

[0011] According to the third aspect of the present invention, the volume average particle diameter of the layered structure compound particles is 0.4 μm or more and less than 3.0 μm.

[0012] According to the fourth aspect of the present invention, the mass ratio Ma / Mb of the content Ma of the layered structure compound particles to the content Mb of the free oil is 0.2 or more and 100 or less.

[0013] According to the fifth aspect of the present invention, the content of the free oil is 0.01% by mass or more and 0.12% by mass or less with respect to the entire electrophotographic developer toner.

[0014] According to the sixth aspect of the present invention, the volume average particle diameter of the layered structure compound particles is 0.5 μm or more and 2.5 μm or less.

[0015] According to the seventh aspect of the present invention, it further includes oil-treated particles.

[0016] According to the eighth aspect of the present invention, the oil-treated particles include oil-treated silica particles.

[0017] According to the ninth aspect of the present invention, the mass ratio Mc / Ma of the content Mc of the oil-treated particles to the content Ma of the layered structure compound particles is 0.5 or more and 400 or less.

[0018] According to the tenth aspect of the present invention, the mass ratio Mc / Ma of the content Mc of the oil-treated particles to the content Ma of the layered structure compound particles is 0.5 or more and 200 or less.

[0019] According to the 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, fluorinated graphite particles, molybdenum disulfide particles, and mica particles.

[0020] According to the twelfth aspect of the present invention, there is provided an electrophotographic developer including the above electrophotographic developer toner.

[0021] According to the thirteenth aspect of the present invention, there is provided a toner cartridge that can be loaded and unloaded in an image forming apparatus and stores the above electrophotographic developer toner.

[0022] According to the 14th aspect of the present invention, there is provided a process cartridge detachably mounted in an image forming apparatus, comprising: an image holding member; a developing mechanism that stores the electrostatic image developer and develops an electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer; and a cleaning mechanism that has a blade in contact with the surface of the image holding member and cleans the toner remaining on the surface of the image holding member after the transfer of the toner image using the blade.

[0023] According to the 15th aspect of the present invention, there is provided an image forming apparatus, comprising: an image holding member; a charging mechanism that charges the surface of the image holding member; an electrostatic image forming mechanism that forms an electrostatic image on the surface of the charged image holding member; a developing mechanism that stores the electrostatic image developer and develops the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer; a transfer mechanism that transfers the toner image formed on the surface of the image holding member to the surface of a recording medium; a fixing mechanism that fixes the toner image transferred to the surface of the recording medium; and a cleaning mechanism that has a blade in contact with the surface of the image holding member and cleans the toner remaining on the surface of the image holding member after the transfer of the toner image using the blade.

[0024] According to the 16th aspect of the present invention, there is provided an image forming method, having the following steps: a charging step of charging the surface of an image holding member; an electrostatic image forming step of forming an electrostatic image on the surface of the charged 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; a transfer step of transferring the toner image formed on the surface of the image holding member to the surface of a recording medium; a fixing step of fixing the toner image transferred to the surface of the recording medium; and a cleaning step of bringing a blade into contact with the surface of the image holding member after the transfer of the toner image and cleaning the toner remaining on the surface of the image holding member.

[0025] Effects of the Invention

[0026] According to the 1st, 7th, 8th, or 11th aspect described above, there is provided an electrostatic image developing toner. Compared with an electrostatic image developing toner containing toner particles, layered structure compound particles, and free oil, and having a mass ratio Ma / Mb of the content Ma of the layered structure compound particles to the content Mb of the free oil less than 0.05 or greater than 100, the provided aspect can suppress the generation of color streaks caused by wear of the cleaning blade by the image holding member during continuous imaging in a high-temperature and high-humidity environment, and can suppress the generation of color streaks caused by leakage of the toner from the contact portion between the image holding member and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment.

[0027] According to the above-described second aspect, there is provided a toner for electrostatic image development. Compared with a toner for electrostatic image development in which the content of free oil is less than 0.005% by mass or more than 0.2% by mass with respect to the entire toner for electrostatic image development, the provided aspect can suppress the generation of color stripes caused by wear of the cleaning blade by the image carrier during continuous imaging in a high-temperature and high-humidity environment, and can suppress the generation of color stripes caused by leakage of the toner from the contact portion between the image carrier and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment.

[0028] According to the above-described third aspect, there is provided a toner for electrostatic image development. Compared with a toner for electrostatic image development in which the volume average particle diameter of the layered structure compound particles is less than 0.4 μm or 3.0 μm or more, the provided aspect can suppress the generation of color stripes caused by wear of the cleaning blade by the image carrier during continuous imaging in a high-temperature and high-humidity environment, and can suppress the generation of color stripes caused by leakage of the toner from the contact portion between the image carrier and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment.

[0029] According to the above-described fourth aspect, there is provided a toner for electrostatic image development. Compared with a toner for electrostatic image development in which the mass ratio Ma / Mb of the content Ma of the layered structure compound particles to the content Mb of the free oil is less than 0.2 or more than 100, the provided aspect can suppress the generation of color stripes caused by wear of the cleaning blade by the image carrier during continuous imaging in a high-temperature and high-humidity environment, and can suppress the generation of color stripes caused by leakage of the toner from the contact portion between the image carrier and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment.

[0030] According to the above-described fifth aspect, there is provided a toner for electrostatic image development. Compared with a toner for electrostatic image development in which the content of free oil is less than 0.01% by mass or more than 0.12% by mass with respect to the entire toner for electrostatic image development, the provided aspect can suppress the generation of color stripes caused by wear of the cleaning blade by the image carrier during continuous imaging in a high-temperature and high-humidity environment, and can suppress the generation of color stripes caused by leakage of the toner from the contact portion between the image carrier and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment.

[0031] According to the above-described sixth aspect, there is provided a toner for electrostatic image development. Compared with a toner for electrostatic image development in which the volume average particle diameter of the layered structure compound particles is less than 0.5 μm or more than 2.5 μm, the provided aspect can suppress the generation of color stripes caused by wear of the cleaning blade by the image carrier during continuous imaging in a high-temperature and high-humidity environment, and can suppress the generation of color stripes caused by leakage of the toner from the contact portion between the image carrier and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment.

[0032] According to the above-mentioned ninth aspect, there is provided a toner for electrostatic image development. Compared with a toner for electrostatic image development in which the mass ratio Mc / Ma of the content Mc of the layered structure compound particles to the content Ma of the oil-treated particles is less than 0.5 or greater than 400, the provided aspect can suppress the generation of color stripes caused by the abrasion of the cleaning blade by the image carrier during continuous imaging in a high-temperature and high-humidity environment, and can suppress the generation of color stripes caused by the leakage of the toner from the contact portion between the image carrier and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment.

[0033] According to the above-mentioned tenth aspect, there is provided a toner for electrostatic image development. Compared with a toner for electrostatic image development in which the mass ratio Mc / Ma of the content Mc of the layered structure compound particles to the content Ma of the oil-treated particles is less than 0.5 or greater than 200, the provided aspect can suppress the generation of color stripes caused by the abrasion of the cleaning blade by the image carrier during continuous imaging in a high-temperature and high-humidity environment, and can suppress the generation of color stripes caused by the leakage of the toner from the contact portion between the image carrier and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment.

[0034] According to the above-mentioned twelfth aspect, there is provided an electrostatic image developer. Compared with the case where the toner for electrostatic image development contains toner particles, layered structure compound particles, and free oil, and the mass ratio Ma / Mb of the content Ma of the layered structure compound particles to the content Mb of the free oil is less than 0.05 or greater than 100, the provided aspect can suppress the generation of color stripes caused by the abrasion of the cleaning blade by the image carrier during continuous imaging in a high-temperature and high-humidity environment, and can suppress the generation of color stripes caused by the leakage of the toner from the contact portion between the image carrier and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment.

[0035] According to the above-mentioned thirteenth aspect, there is provided a toner cartridge. Compared with the case where the toner for electrostatic image development contains toner particles, layered structure compound particles, and free oil, and the mass ratio Ma / Mb of the content Ma of the layered structure compound particles to the content Mb of the free oil is less than 0.05 or greater than 100, the provided aspect can suppress the generation of color stripes caused by the abrasion of the cleaning blade by the image carrier during continuous imaging in a high-temperature and high-humidity environment, and can suppress the generation of color stripes caused by the leakage of the toner from the contact portion between the image carrier and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment.

[0036] According to the 14th solution described above, a processing cartridge is provided. Compared with the case where the toner for electrostatic image development contains toner particles, layered structure compound particles, and free oil, and the mass-based ratio Ma / Mb of the content Ma of the layered structure compound particles to the content Mb of the free oil is less than 0.05 or greater than 100, the provided solution can suppress the generation of color stripes caused by the abrasion of the image carrier on the cleaning blade during continuous imaging in a high-temperature and high-humidity environment, and can suppress the generation of color stripes caused by the leakage of toner from the contact portion between the image carrier and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment.

[0037] According to the 15th solution described above, an image forming apparatus is provided. Compared with the case where the toner for electrostatic image development contains toner particles, layered structure compound particles, and free oil, and the mass-based ratio Ma / Mb of the content Ma of the layered structure compound particles to the content Mb of the free oil is less than 0.05 or greater than 100, the provided solution can suppress the generation of color stripes caused by the abrasion of the image carrier on the cleaning blade during continuous imaging in a high-temperature and high-humidity environment, and can suppress the generation of color stripes caused by the leakage of toner from the contact portion between the image carrier and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment.

[0038] According to the 16th solution described above, an image forming method is provided. Compared with the case where the toner for electrostatic image development contains toner particles, layered structure compound particles, and free oil, and the mass-based ratio Ma / Mb of the content Ma of the layered structure compound particles to the content Mb of the free oil is less than 0.05 or greater than 100, the provided solution can suppress the generation of color stripes caused by the abrasion of the image carrier on the cleaning blade during continuous imaging in a high-temperature and high-humidity environment, and can suppress the generation of color stripes caused by the leakage of toner from the contact portion between the image carrier and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic configuration diagram showing an example of the image forming apparatus of the present embodiment.

[0040] Figure 2 It is a schematic configuration diagram showing an example of the processing cartridge that is loaded and unloaded in the image forming apparatus of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0041] Hereinafter, embodiments of the present invention will be described. These descriptions and examples are used to illustrate the embodiments, and do not limit the scope of the embodiments.

[0042] In the present invention, the numerical range represented by "~" means a range that includes the values described before and after "~" as the minimum value and the maximum value, respectively.

[0043] In the numerical ranges described step by step in the present invention, the upper limit value or the lower limit value described in one numerical range can be replaced with the upper limit value or the lower limit value of the numerical range of other steps described. In addition, in the numerical ranges described in the present invention, the upper limit value or the lower limit value of the numerical range can be replaced with the value shown in the examples.

[0044] The term "step" in the present invention includes not only independent steps, but also, even in cases where it cannot be clearly distinguished from other steps, as long as the desired purpose of the step can be achieved, it is also included in this term.

[0045] When describing the embodiments of the present invention with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. In addition, the sizes of the components in each drawing are schematic, and the relative relationship of the sizes between the components is not limited thereto.

[0046] Each component in the present invention may include two or more corresponding substances. When referring to the amounts of the components in the composition of the present invention, in cases where 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.

[0047] The particles corresponding to each component in the present invention may include two or more. In cases where there are two or more particles corresponding to each component in the composition, unless otherwise stated, the particle size of each component refers to the value for the mixture of the two or more particles present in the composition.

[0048] In the present invention, "toner for electrostatic image development" is also abbreviated as "toner", and "electrostatic image developer" is also abbreviated as "developer".

[0049] <Toner for Electrostatic Image Development>

[0050] The toner of this embodiment includes toner particles, layered structure compound particles, and free oil, and the mass-based ratio Ma / Mb of the content Ma of the layered structure compound particles to the content Mb of the free oil is 0.05 or more and 100 or less.

[0051] The toner of this embodiment can suppress the generation of color streaks caused by the abrasion of the cleaning blade by the image holding member during continuous imaging in a high-temperature and high-humidity environment (for example, a temperature of 28°C and a relative humidity of 85%), and can suppress the generation of color streaks caused by the leakage of the toner from the contact portion between the image holding member and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment (for example, a temperature of 10°C and a relative humidity of 10%). As its mechanism, it is speculated as follows.

[0052] Conventionally, toners externally added with particulate compounds having a layered structure (such as melamine cyanurate particles and boron nitride particles) have been known. The particulate compounds having a layered structure are compound particles having a laminated structure with an interlayer distance on the order of angstroms and are believed to exhibit a lubricating effect by mutual slippage (displacement) between the layers. The particulate compounds having a layered structure externally added to the toner function as a lubricant at the contact portion between the image holding member and the cleaning blade.

[0053] The particulate compounds having a layered structure are materials that are relatively less likely to absorb moisture. Therefore, even in a situation where imaging is performed in a high-temperature and high-humidity environment (that is, a situation where a voltage is applied to the particulate compounds having a layered structure on the image holding member in a high-temperature and high-humidity environment), deterioration is less likely to occur, and the lubricating effect is likely to continue. However, if imaging is continuously performed for a long time in a high-temperature and high-humidity environment, the lubricating effect of the particulate compounds having a layered structure is lost, and colored stripes may be generated due to wear of the cleaning blade.

[0054] In addition, the external additives aggregate with each other at the contact portion between the cleaning blade and the image holding member to form a deposit (so-called external additive dam), and the particulate compounds having a layered structure are materials that are less likely to form an external additive dam than other external additives. Therefore, when imaging is continuously performed for a long time in a low-temperature and low-humidity environment (that is, a situation where an external additive dam is less likely to be formed) using a toner containing particulate compounds having a layered structure, the external additive dam becomes fragile and the toner leaks out, thereby possibly causing the generation of colored stripes.

[0055] In order to address the above problems, in the present embodiment, when a free oil is included together with the particulate compounds having a layered structure in the toner and the amount of the free oil is within an appropriate range, it is speculated that the particulate compounds having a layered structure are less likely to deteriorate and the strength of the external additive dam is increased.

[0056] Therefore, it is speculated that if the toner of the present embodiment is used, generation of colored stripes caused by wear of the cleaning blade by the image holding member during continuous imaging in a high-temperature and high-humidity environment can be suppressed, and generation of colored stripes caused by leakage of the toner from the contact portion between the image holding member and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment can be suppressed.

[0057] In the toner of the present embodiment, the mass ratio Ma / Mb of the content Ma of the particulate compounds having a layered structure to the content Mb of the free oil is 0.05 or more and 100 or less.

[0058] When the ratio Ma / Mb is less than 0.05, that is, when the amount of the free oil is relatively excessive, it is speculated that the free oil hinders the slidability of the particulate compounds having a layered structure, and colored stripes are generated due to wear of the cleaning blade by the image holding member during continuous imaging in a high-temperature and high-humidity environment.

[0059] When the ratio Ma / Mb is greater than 100, that is, when the free oil amount is relatively too small, it is speculated that the strength of the externally added agent dam cannot be sufficiently improved, and color stripes will be generated due to the leakage of the toner from the contact part between the image holding body and the cleaning blade during continuous imaging in a low-temperature and low-humidity environment.

[0060] From the above aspects, the ratio Ma / Mb is more preferably 0.2 or more and 100 or less, and further preferably 0.5 or more and 80 or less.

[0061] Hereinafter, the components, structure, and characteristics of the toner of the present embodiment will be described in detail.

[0062] [Toner particles]

[0063] The toner particles are composed of, for example, a binder resin and, if necessary, a colorant, a release agent, and other additives.

[0064] -Binder resin-

[0065] As the binder resin, for example, vinyl resins formed from homopolymers of the following monomers or copolymers formed by combining two or more of these monomers can be mentioned. The monomers are: styrenes (such as styrene, p-chlorostyrene, α-methylstyrene, etc.), (meth)acrylates (such as 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 (such as acrylonitrile, methacrylonitrile, etc.), vinyl ethers (such as vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (such as vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (such as ethylene, propylene, butadiene, etc.), etc.

[0066] As the binder resin, non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, modified rosin, etc., mixtures of these resins with the above vinyl resins, or graft polymers obtained by polymerizing vinyl monomers in their coexistence can also be mentioned.

[0067] These binder resins can be used alone or in combination of two or more.

[0068] As the binder resin, a polyester resin is suitable.

[0069] As the polyester resin, known amorphous polyester resins can be cited, for example. Among the polyester resins, the amorphous polyester resin can also be used in combination with the crystalline polyester resin. Among them, the crystalline polyester resin may be used in a range of 2% by mass or more and 40% by mass or less (preferably 2% by mass or more and 20% by mass or less) based on all the adhesive resins.

[0070] "Crystallinity" of the resin means that there is no stepwise heat absorption change in differential scanning calorimetry (DSC) and there is a clear endothermic peak. Specifically, it means that the half-peak width of the endothermic peak measured at a heating rate of 10 (°C / min) is within 10 °C.

[0071] On the other hand, "amorphousness" of the resin means that the half-peak width is greater than 10 °C, showing a stepwise heat absorption change or no clear endothermic peak is found.

[0072] · Amorphous polyester resin

[0073] As the amorphous polyester resin, for example, condensates of polycarboxylic acids and polyols can be cited. As the amorphous polyester resin, commercially available products or synthetic products can be used.

[0074] As the polycarboxylic acid, for example, aliphatic dicarboxylic acids (such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, pentenedioic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (such as cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (such as terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their acid anhydrides, or their lower (e.g., having 1 to 5 carbon atoms) alkyl esters. Among these, as the polycarboxylic acid, aromatic dicarboxylic acids are preferably used, for example.

[0075] Among the polycarboxylic acids, dicarboxylic acids can also be used in combination with polycarboxylic acids having a crosslinked structure or a branched structure with 3 or more carbon atoms. As the polycarboxylic acids having 3 or more carbon atoms, for example, trimellitic acid, pyromellitic acid, their acid anhydrides, or their lower (e.g., having 1 to 5 carbon atoms) alkyl esters, etc. can be cited.

[0076] The polycarboxylic acid can be used alone or in combination of two or more.

[0077] As the polyol, for example, aliphatic diols (such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol, etc.), alicyclic diols (such as cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), aromatic diols (such as ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc.). Among these, as the polyol, aromatic diols and alicyclic diols are preferably used, for example, and aromatic diols are more preferably used.

[0078] As the polyol, a diol can be used in combination with a polyol having a crosslinked structure or a branched structure and having 3 or more hydroxyl groups. Examples of the polyol having 3 or more hydroxyl groups include glycerin, trimethylolpropane, and pentaerythritol.

[0079] The polyol may be used alone or two or more thereof may be used in combination.

[0080] The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50°C or higher and 80°C or lower, more preferably 50°C or higher and 65°C or lower.

[0081] The glass transition temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC). More specifically, it is determined by the "extrapolated glass transition start temperature" described in the method for measuring the glass transition temperature in JIS K7121:1987 "Method for Measuring the Transition Temperature of Plastics".

[0082] The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 or higher and 1,000,000 or lower, more preferably 7,000 or higher and 500,000 or lower.

[0083] The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2,000 or higher and 100,000 or lower.

[0084] The molecular weight distribution Mw / Mn of the amorphous polyester resin is preferably 1.5 or higher and 100 or lower, more preferably 2 or higher and 60 or lower.

[0085] The weight average molecular weight and the number average molecular weight are measured by gel permeation chromatography (GPC). In the molecular weight measurement using GPC, as the measurement device, GPC·HLC-8120GPC manufactured by Tosoh Corporation is used, and a column·TSKgel SuperHM-M (15 cm) manufactured by Tosoh Corporation is used, and the measurement is carried out using a THF solvent. The weight average molecular weight and the number average molecular weight are calculated from the measurement results using a molecular weight calibration curve prepared using a monodisperse polystyrene standard sample.

[0086] The amorphous polyester resin is obtained by a known production method. Specifically, for example, it is obtained by the following method: the polymerization temperature is 180°C or higher and 230°C or lower, and the inside of the reaction system is depressurized as needed, and the reaction is carried out while removing the water or alcohol generated during condensation.

[0087] When the raw material monomers are insoluble or incompatible at the reaction temperature, a high-boiling solvent may be added as a dissolution aid to dissolve them. In this case, the dissolution aid is distilled off while carrying out the polycondensation reaction. In the case where there are monomers with poor compatibility in the copolymerization reaction, the monomers with poor compatibility and a specific acid or alcohol that undergoes polycondensation with the monomer may be pre-condensed, and then polycondensed with the main component.

[0088] · Crystalline polyester resin

[0089] As the crystalline polyester resin, for example, a polycondensate of a polycarboxylic acid and a polyol can be cited. As the crystalline polyester resin, a commercially available product or a synthesized product can be used.

[0090] Here, in order to make the crystalline polyester resin easily form a crystal structure, compared with the polycondensate obtained by using a polymerizable monomer having an aromatic ring, the crystalline polyester resin preferably uses a polycondensate obtained by using a linear aliphatic polymerizable monomer.

[0091] As the polycarboxylic acid, for example, aliphatic dicarboxylic acids (such as 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 (such as phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid and other dibasic acids, etc.), their acid anhydrides, or their lower (e.g., having 1 to 5 carbon atoms) alkyl esters can be cited.

[0092] Among the polycarboxylic acids, a dicarboxylic acid and a polycarboxylic acid having a crosslinked structure or a branched structure with 3 or more carbon atoms can also be used in combination. As the tricarboxylic acid, for example, aromatic carboxylic acids (such as 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), their acid anhydrides, or their lower (e.g., having 1 to 5 carbon atoms) alkyl esters can be cited.

[0093] As the polycarboxylic acid, these dicarboxylic acids can be used in combination with a dicarboxylic acid having a sulfonic acid group and a dicarboxylic acid having an ethylenic double bond.

[0094] The polycarboxylic acid can be used alone or in combination of two or more.

[0095] As the polyol, for example, aliphatic diols (such as linear aliphatic diols having 7 or more and 20 or less carbon atoms in the main chain part) can be cited. As the aliphatic diol, for example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosanediol (1,14-eicosanedecanediol), etc. Among these, as the aliphatic diol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred.

[0096] Among polyhydric alcohols, a diol can also be used in combination with an alcohol having a crosslinked structure or a branched structure and having 3 or more carbon atoms. Examples of the alcohol having 3 or more carbon atoms include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, etc.

[0097] One kind of polyhydric alcohol can be used alone, or two or more kinds can be used in combination.

[0098] Here, in the polyhydric alcohol, the content of the aliphatic diol is preferably 80 mol% or more, more preferably 90 mol% or more.

[0099] The melting temperature of the crystalline polyester resin is preferably 50°C or higher and 100°C or lower, more preferably 55°C or higher and 90°C or lower, and still more preferably 60°C or higher and 85°C or lower.

[0100] The melting temperature is determined as the "melting peak temperature" described in the melting temperature measurement method of JIS K7121:1987 "Method for Measuring the Transition Temperature of Plastics" based on the DSC curve obtained by differential scanning calorimetry (DSC).

[0101] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

[0102] The crystalline polyester resin is obtained, for example, by a known production method in the same manner as the amorphous polyester.

[0103] The content of the adhesive resin is preferably 40 mass% or more and 95 mass% or less, more preferably 50 mass% or more and 90 mass% or less, and still more preferably 60 mass% or more and 85 mass% or less with respect to the whole toner particles.

[0104] -Colorant-

[0105] Examples of the colorant include pigments such as carbon black, chrome yellow, Hansa yellow, benzidine yellow, vat yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, sulfur-fast orange, Vulcan red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, lithol red, rhodamine B lake, lake red C, pigment red, rose red, aniline blue, ultramarine blue, oil-soluble blue, methylene chloride blue, phthalocyanine blue, pigment blue, phthalocyanine green, malachite green oxalate, etc.; dyes such as acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, aniline black-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, thiazole-based dyes.

[0106] One kind of colorant can be used alone, or two or more kinds can be used in combination.

[0107] The colorant used may be a colorant that has been surface-treated as needed, or it may be used in combination with a dispersant. Additionally, two or more colorants may be used in combination.

[0108] The content of the colorant is preferably 1% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 15% by mass or less, relative to the total color toner particles.

[0109] -Release agent-

[0110] Examples of the release agent include: hydrocarbon waxes; natural waxes such as carnauba wax, rice bran wax, and candelilla wax; synthetic or mineral·petroleum-based waxes such as montan wax; ester-based waxes such as fatty acid esters and montanic acid esters; and so on. The release agent is not limited to these.

[0111] The melting temperature of the release agent is preferably 50°C or more and 110°C or less, more preferably 60°C or more and 100°C or less.

[0112] The melting temperature is determined by the "melting peak temperature" described in the melting temperature measurement method of JIS K7121:1987 "Test Method for Transition Temperature of Plastics" based on the DSC curve obtained by differential scanning calorimetry (DSC).

[0113] The content of the release agent is preferably 1% by mass or more and 20% by mass or less, more preferably 5% by mass or more and 15% by mass or less, relative to the total color toner particles.

[0114] -Other additives-

[0115] Examples of other additives include known additives such as magnetic materials, charge control agents, and inorganic powders. These additives can be included as internal additives in the color toner particles.

[0116] -Properties of color toner particles, etc.-

[0117] The color toner particles may be single-layer color toner particles or so-called core / shell structure color toner particles composed of a core (nuclear particle) and a coating layer (shell layer) covering the core.

[0118] The core / shell structure color toner particles may be composed of a core and a coating layer, for example. The core is formed by including a binder resin and other additives such as a colorant and a release agent as necessary, and the coating layer is formed by including a binder resin.

[0119] The volume average particle diameter (D50v) of the color toner particles is preferably 2 μm or more and 10 μm or less, more preferably 4 μm or more and 8 μm or less.

[0120] Regarding various average particle diameters and various particle size distribution indices of the toner particles, measurements were performed using a Coulter Multisizer II (manufactured by Beckman Coulter), with the electrolyte being ISOTON-II (manufactured by Beckman Coulter).

[0121] During the measurement, 0.5 mg or more and 50 mg or less of the measurement sample was added to 2 ml of a 5 mass% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant. This was added to 100 ml or more and 150 ml or less of the electrolyte.

[0122] The electrolyte in which the sample was suspended was dispersed for 1 minute using an ultrasonic disperser, and the particle size distribution of particles with a particle diameter in the range of 2 μm or more and 60 μm or less was measured using a Coulter Multisizer II with a pore diameter of 100 μm. The number of sampled particles was 50,000.

[0123] For the particle size ranges (sections) divided based on the measured particle size distribution, the volume and number were respectively plotted as cumulative distributions starting from the smaller diameter side, and the particle diameter at the cumulative 16% point was defined as the volume particle diameter D16v and the number particle diameter D16p, the particle diameter at the cumulative 50% point was defined as the volume average particle diameter D50v and the cumulative number average particle diameter D50p, and the particle diameter at the cumulative 84% point was defined as the volume particle diameter D84v and the number particle diameter D84p.

[0124] Using these values, the volume particle size distribution index (GSDv) was calculated as (D84v / D16v) 1 / 2 and the number particle size distribution index (GSDp) was calculated as (D84p / D16p). 1 / 2

[0125] The average roundness of the toner particles is preferably 0.94 or more and 1.00 or less, more preferably 0.95 or more and 0.98 or less.

[0126] The average roundness of the toner particles is obtained from (equivalent circle 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 obtained by measurement using the following method.

[0127] First, the toner particles to be measured were aspirated and collected to form a flat flow, and a particle image as a still image was obtained by making it flash instantaneously. The average roundness was obtained using a flow particle image analysis device (FPIA - 3000 manufactured by Sysmex Corporation) that performs image analysis on this particle image. And the number of samples when obtaining the average roundness was set to 3500.

[0128] ​When the toner has an external additive, the toner (developer) to be measured is dispersed in water containing a surfactant, and then ultrasonic treatment is performed to obtain toner particles after removing the external additive.

[0129] [Lamellar structure compound particles]

[0130] Lamellar structure compound particles are particles of a compound having a laminated structure. Examples of the lamellar structure compound particles include melamine cyanurate particles, boron nitride particles, graphite fluoride particles, molybdenum disulfide particles, mica particles, and the like.

[0131] From the aspect of suppressing the generation of color stripes, the volume average particle diameter of the lamellar structure compound particles is preferably 0.4 μm or more and less than 3.0 μm. When the volume average particle diameter of the lamellar structure compound particles is 0.4 μm or more, it is presumed that deterioration is not likely to occur under the condition of applying voltage for a long time in a high-temperature and high-humidity environment. When the volume average particle diameter of the lamellar structure compound particles is less than 3.0 μm, it is presumed that an external additive dam is easily formed.

[0132] From the above aspects, the volume average particle diameter of the lamellar structure compound particles is more preferably 0.5 μm or more and 2.5 μm or less, and further preferably 0.5 μm or more and 2.0 μm or less. The volume average particle diameter of the lamellar structure compound particles can be controlled by pulverization, classification, or a combination of pulverization and classification.

[0133] The volume average particle diameter of the lamellar structure compound is determined by the following measurement method.

[0134] First, the lamellar structure compound particles are separated from the toner. There is no limitation on the method for separating the lamellar structure compound particles from the toner. For example, the toner is dispersed in water containing a surfactant, ultrasonic waves are applied to the obtained dispersion liquid, and then the dispersion liquid is centrifuged at high speed, and the toner particles, lamellar structure compound particles, and other external additives are centrifuged and separated according to their specific gravities. The fraction containing the lamellar structure compound particles is extracted and dried to obtain the lamellar structure compound particles.

[0135] Next, the lamellar structure compound particles are added to an electrolyte aqueous solution (isotonic aqueous solution), and ultrasonic waves are applied for 30 seconds or more to disperse them. This dispersion liquid is used as a sample, and the particle diameter is measured using a laser diffraction scattering type particle size distribution measuring device (for example, manufactured by Microtrac BEL Corporation, Microtrac MT3000II). At least 3000 lamellar structure compound particles are measured, and the particle diameter at the 50% cumulative point from the small-diameter side in the volume-based particle size distribution is taken as the volume average particle diameter.

[0136] From the aspect of suppressing the generation of color stripes, the content of the layered structure compound particles is preferably 0.01% by mass or more and 1.0% by mass or less, more preferably 0.03% by mass or more and 0.8% by mass or less, and further preferably 0.05% by mass or more and 0.6% by mass or less, relative to the whole toner.

[0137] [Free oil, oil-treated particles]

[0138] Examples of the free oil include silicone oil, paraffin oil, fluorine oil, vegetable oil, etc. The free oil may be one kind or two or more kinds. Among these, silicone oil is preferred, and dimethyl silicone oil is more preferred.

[0139] From the aspect of suppressing the generation of color stripes, the content of the free oil is preferably 0.005% by mass or more and 0.2% by mass or less, more preferably 0.01% by mass or more and 0.12% by mass or less, and further preferably 0.02% by mass or more and 0.08% by mass or less, relative to the whole toner.

[0140] The amount of free oil (%) relative to the whole toner is determined by the following method.

[0141] The toner in the state with an external additive added is dispersed in hexane at a toner concentration of 5% by mass, ultrasonic waves are applied for 20 minutes (output power: 20 W, frequency: 20 kHz), and the supernatant and the solid component are separated by centrifugation. When the mass of the toner as the sample is set as Wb and the amount of the solid component after centrifugation is set as Wa, the amount of free oil (%) relative to the whole toner is represented by the following formula.

[0142] Amount of free oil (%) = (Wb - Wa) ÷ Wb × 100

[0143] The free oil contained in the toner may be the oil added to the toner or the oil freed from the external additive of the toner. From the aspect of easily adjusting the content of the free oil, it is preferred to externally add oil-treated particles to the toner so that the toner contains free oil.

[0144] Examples of the oil-treated particles include oil-treated inorganic particles (such as SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, etc.), oil-treated resin particles (such as resin particles of polystyrene, polymethyl methacrylate, melamine resin, etc.), and oil-treated cleaning agents (such as metal salts of higher fatty acids represented by zinc stearate, particles of fluorine-based high molecular weight substances). Among them, oil-treated silica particles are preferred as the oil-treated particles.

[0145] The oil treatment of the particles can be carried out, for example, by dispersing the particles in an oil dissolved in an alcohol and then drying them by distilling off the alcohol using an evaporator. Examples of the oil include silicone oil, paraffin oil, fluorine oil, vegetable oil, etc. Among these, silicone oil is preferred, and dimethyl silicone oil is more preferred.

[0146] The free oil content in the oil-treated particles is measured by the following method.

[0147] The oil-treated particles are dispersed in hexane at a concentration of 5% by mass, ultrasonic waves are applied for 20 minutes (output power 20 W, frequency 20 kHz), and the supernatant and solid components are separated by centrifugation. When the mass of the oil-treated particles as the sample is Wb and the amount of the solid components after centrifugation is Wa, the free oil content (mass%) in the oil-treated particles is represented by the following formula.

[0148] Free oil content (mass%) = (Wb - Wa) ÷ Wb × 100

[0149] From the aspect of suppressing the generation of color stripes, the volume average particle diameter of the oil-treated particles is preferably 40 nm or more and 300 nm or less, more preferably 50 nm or more and 250 nm or less, and further preferably 50 nm or more and 200 nm or less.

[0150] From the aspect of suppressing the generation of color stripes, the content of the oil-treated particles is preferably 0.5% by mass or more and 4.0% by mass or less, more preferably 0.5% by mass or more and 3.5% by mass or less, and further preferably 0.7% by mass or more and 3.0% by mass or less, relative to the entire toner.

[0151] From the aspect of suppressing the generation of color stripes, the mass ratio Mc / Ma of the content Mc of the oil-treated particles to the content Ma of the layered structure compound particles is preferably 0.5 or more and 400 or less, more preferably 0.5 or more and 200 or less, and further preferably 0.7 or more and 150 or less.

[0152] [Other external additives]

[0153] The toner of the present embodiment may contain other external additives other than the oil-treated particles, that is, particles not treated with oil. Examples of the particles not treated with oil include inorganic particles (such as SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, etc.), resin particles (such as resin particles of polystyrene, polymethyl methacrylate, melamine resin, etc.), cleaning agents (such as metal salts of higher fatty acids represented by zinc stearate, particles of fluorine-based high molecular weight substances), etc. These particles may also be particles surface-treated with a hydrophobizing agent other than oil removal (such as a coupling agent).

[0154] When the toner of the present embodiment contains particles not treated with oil, the total amount of the external addition amount of the particles not treated with oil is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.01% by mass or more and 2.0% by mass or less, relative to the toner particles.

[0155] [Method for manufacturing toner]

[0156] The toner of the present embodiment is obtained by externally adding an external additive to the toner particles after manufacturing the toner particles.

[0157] The toner particles can be manufactured by any one of a dry method (such as a kneading and pulverizing method, etc.) and a wet method (such as an aggregation and coalescence method, a suspension polymerization method, a dissolution and suspension method, etc.). These manufacturing methods are not particularly limited, and known manufacturing methods can be adopted. Among these, the toner particles can be obtained by an aggregation and coalescence method (aggregation and unification method).

[0158] Specifically, for example, when manufacturing toner particles by an aggregation and coalescence method (aggregation and unification method), the toner particles are manufactured through the following steps: a step of preparing a resin particle dispersion liquid in which resin particles as a binder resin are dispersed (resin particle dispersion liquid preparation step); a step of aggregating the resin particles (other particles if necessary) in the resin particle dispersion liquid (in the dispersion liquid after mixing other particle dispersion liquids if necessary) to form aggregated particles (aggregated particle formation step); and a step of heating the aggregated particle dispersion liquid in which the aggregated particles are dispersed to fuse / coalesce (fuse and unify) the aggregated particles to form toner particles (fusion / coalescence step).

[0159] Details of each step will be described below.

[0160] In the following description, a method for obtaining toner particles containing a colorant and a release agent will be described. However, the colorant and the release agent are additives used as needed. Of course, other additives other than the colorant and the release agent can also be used.

[0161] - Resin particle dispersion preparation step -

[0162] Prepare a resin particle dispersion in which resin particles as a binder resin are dispersed, and at the same time, prepare, 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.

[0163] The resin particle dispersion is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

[0164] As the dispersion medium used in the resin particle dispersion, an aqueous medium can be cited, for example.

[0165] As the aqueous medium, for example, water such as distilled water and ion-exchanged water, alcohols, etc. can be cited. These media can be used alone or in combination of two or more.

[0166] As the surfactant, for example, the following can be cited: anionic surfactants such as sulfate ester salts, sulfonates, phosphate esters, 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 so on. Among these, anionic surfactants and cationic surfactants can be particularly cited. Nonionic surfactants can also be used in combination with anionic surfactants or cationic surfactants.

[0167] The surfactant can be used alone or in combination of two or more.

[0168] In the resin particle dispersion, as a method for dispersing resin particles in a dispersion medium, common dispersion methods such as using a rotary shear homogenizer or a ball mill, sand mill, bead mill, etc. having a medium can be cited, for example. In addition, depending on the type of resin particles, the resin particles can also be dispersed in the dispersion medium by a phase inversion emulsification method. The phase inversion emulsification method is the following method: dissolve the resin to be dispersed in a hydrophobic organic solvent that can dissolve the resin, add an alkali to the organic continuous phase (O phase) for neutralization, and then introduce an aqueous medium (W phase), thereby inverting from W / O to O / W and dispersing the resin in a particulate form in the aqueous medium.

[0169] As the volume average particle diameter of the resin particles dispersed in the resin particle dispersion, for example, it is 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.

[0170] Regarding the volume-average particle diameter of the resin particles, using the particle size distribution obtained by measurement with a laser diffraction particle size distribution measuring device (e.g., LA-700 manufactured by Horiba, Ltd.), for the divided particle size ranges (sections), the cumulative distribution is plotted for volume starting from the small particle size side, and the particle diameter at the cumulative 50% point with respect to all the particles is measured and taken as the volume-average particle diameter D50v. The volume-average particle diameter of the particles in other dispersions is also measured in the same manner.

[0171] 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, more preferably 10% by mass or more and 40% by mass or less.

[0172] Similarly to the resin particle dispersion, for example, a colorant particle dispersion and a release agent particle dispersion are also prepared. That is, with respect to the volume-average particle diameter of the particles, the dispersion medium, the dispersion method, and the content of the particles in the resin particle dispersion, the same applies to the colorant particles dispersed in the colorant particle dispersion and the release agent particles dispersed in the release agent particle dispersion.

[0173] -Agglomerate Particle Formation Step-

[0174] Next, the resin particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mixed.

[0175] Thereafter, in the mixed dispersion, the resin particles, the colorant particles, and the release agent particles are hetero-aggregated to form agglomerate particles having a diameter close to the diameter of the target toner particles and containing the resin particles, the colorant particles, and the release agent particles.

[0176] Specifically, for example, a flocculant is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to acidic (e.g., pH 2 or more and 5 or less), and 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 - 30°C to the glass transition temperature of the resin particles - 10°C) to cause the particles dispersed in the mixed dispersion to agglomerate and form agglomerate particles.

[0177] In the agglomerate particle formation step, for example, a flocculant can be added at room temperature (e.g., 25°C) while stirring the mixed dispersion with a rotary shear homogenizer, the pH of the mixed dispersion is adjusted to acidic (e.g., pH 2 or more and 5 or less), and after adding a dispersion stabilizer as needed, heating is carried out.

[0178] As a flocculant, for example, surfactants having a polarity opposite to that of the surfactant contained in the mixed dispersion, inorganic metal salts, and metal complexes having a valence of 2 or more can be cited. When a metal complex is used as the flocculant, the amount of the surfactant used is reduced and the charging characteristics are improved.

[0179] If necessary, an additive that forms a complex or a similar bond with the metal ion of the flocculant can be used together with the flocculant. As the additive, a chelating agent is preferably used.

[0180] As the inorganic metal salt, for example, metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate can be cited; inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide; and the like.

[0181] As the chelating agent, a water-soluble chelating agent can be used. As the chelating agent, for example, hydroxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid can be cited; aminocarboxylic acids such as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA); and the like.

[0182] The addition amount of the chelating agent is preferably 0.01 part by mass or more and 5.0 parts by mass or less, more preferably 0.1 part by mass or more and less than 3.0 parts by mass with respect to 100 parts by mass of the resin particles.

[0183] -Fusion / Merging Step-

[0184] Next, the flocculated particle dispersion in which the flocculated particles are dispersed is heated to, for example, a temperature above the glass transition temperature of the resin particles (for example, a temperature 10°C to 30°C higher than the glass transition temperature of the resin particles), and the flocculated particles are fused / merged to form toner particles.

[0185] Through the above steps, toner particles are obtained.

[0186] After obtaining the flocculated particle dispersion in which the flocculated particles are dispersed, toner particles can be manufactured through the following steps: a step of further mixing the flocculated particle dispersion with a resin particle dispersion in which the resin particles are dispersed, and aggregating in such a manner that the resin particles further adhere to the surface of the flocculated particles to form second flocculated particles; and a step of heating the second flocculated particle dispersion in which the second flocculated particles are dispersed to fuse / merge the second flocculated particles to form toner particles having a core / shell structure.

[0187] After the fusion / merging step, known cleaning steps, solid-liquid separation steps, and drying steps are performed on the toner particles formed in the solution to obtain toner particles in a dry state. Regarding the cleaning step, from the aspect of chargeability, replacement cleaning using ion-exchanged water can be sufficiently performed. Regarding the solid-liquid separation step, from the aspect of productivity, suction filtration, pressure filtration, etc. can be performed. Regarding the drying step, from the aspect of productivity, freeze drying, fluidized bed drying, vibrated fluidized bed drying, etc. can be performed.

[0188] After that, for example, an external additive is added to the obtained toner particles in a dry state and mixed to produce 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. Further, coarse particles of the toner can be removed using a vibrating sieve, an air classifier, etc. as needed.

[0189] <Electrostatic image developer>

[0190] The electrostatic image developer of the present embodiment contains at least the toner of the present embodiment.

[0191] The electrostatic image developer of the present embodiment can be a one-component developer containing only the toner of the present embodiment, or a two-component developer formed by mixing the toner and a carrier.

[0192] There is no particular limitation on the carrier, and known carriers can be cited. As the carrier, for example, a coated carrier in which a resin is coated on the surface of a core material formed of magnetic powder; a magnetic powder-dispersed carrier in which magnetic powder is dispersed and mixed in a base resin; a resin-impregnated carrier in which resin is impregnated in porous magnetic powder; and the like can be cited. The magnetic powder-dispersed carrier and the resin-impregnated carrier can also be carriers in which the constituent particles of the carrier are used as the core material and the surface thereof is coated with resin.

[0193] As the magnetic powder, for example, magnetic metals such as iron, nickel, and cobalt; magnetic oxides such as ferrite and magnetite; and the like can be cited.

[0194] As the resin for coating and the base resin, for example, polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylate copolymer, a pure silicone resin or a modified product thereof formed by including a siloxane bond, a fluororesin, a polyester, a polycarbonate, a phenol resin, an epoxy resin, etc. can be cited. Other additives such as conductive particles can be included in the resin for coating and the base resin. As the conductive particles, particles such as metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, potassium titanate, etc. can be cited.

[0195] When coating the surface of a resin-coated core material, examples include coating methods using a coating solution formed by dissolving a coating resin and various additives (used as needed) in an appropriate solvent. The solvent is not particularly limited and can be selected considering the type of resin used, coating suitability, etc.

[0196] As specific resin coating methods, examples include: an immersion method in which the core material is immersed in the coating solution for forming a coating layer; a spraying method in which the coating solution for forming a coating layer is sprayed onto the surface of the core material; a fluidized bed method in which the coating solution for forming a coating layer is sprayed in a state where the core material is suspended by flowing air; a kneading coater method in which the core material of the carrier and the coating solution for forming a coating layer are mixed in a kneading coater and then the solvent is removed; and so on.

[0197] 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, more preferably 3:100 to 20:100.

[0198] <Image forming apparatus, image forming method>

[0199] The image forming apparatus of the present embodiment includes: an image carrier; a charging mechanism that charges the surface of the image carrier; an electrostatic image forming mechanism that forms an electrostatic image on the surface of the charged image carrier; a developing mechanism that stores an electrostatic image developer and develops the electrostatic image formed on the surface of the image carrier into a toner image using the electrostatic image developer; a transfer mechanism that transfers the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing mechanism that fixes the toner image transferred to the surface of the recording medium; and a cleaning mechanism that has a blade in contact with the surface of the image carrier and uses the blade to clean the toner remaining on the surface of the image carrier after transferring the toner image.

[0200] An image forming method (the image forming method of the present embodiment) is implemented using the image forming apparatus of the present embodiment. The method includes the following steps: a charging step of charging the surface of the image carrier; an electrostatic image forming step of forming an electrostatic image on the surface of the charged image carrier; a developing step of developing the electrostatic image formed on the surface of the image carrier into a toner image using the electrostatic image developer of the present embodiment; a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing step of fixing the toner image transferred to the surface of the recording medium; and a cleaning step of bringing the blade into contact with the surface of the image carrier after transferring the toner image and cleaning the toner remaining on the surface of the image carrier.

[0201] The image forming apparatus according to the present embodiment can be applied to the following well-known image forming apparatuses: an apparatus of a direct transfer method that directly transfers a toner image formed on the surface of an image carrier to a recording medium; an apparatus of an intermediate transfer method that transfers a toner image formed on the surface of an image carrier to the surface of an intermediate transfer body once and then transfers the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium twice; an apparatus having a charge removing mechanism that irradiates the surface of an image carrier with charge removing light for charge removal after transfer of the toner image and before charging; and the like.

[0202] When the image forming apparatus according to the present embodiment is an apparatus of an intermediate transfer method, the transfer mechanism applied, for example, has a configuration including the following components: an intermediate transfer body to which a toner image is transferred; a primary transfer mechanism that transfers a toner image formed on the surface of an image carrier to the surface of the intermediate transfer body once; and a secondary transfer mechanism that transfers the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium twice.

[0203] In the image forming apparatus according to the present embodiment, for example, a portion including a developing mechanism may be a cartridge structure (processing cartridge) that can be loaded and unloaded in the image forming apparatus. As the processing cartridge, for example, a processing cartridge that stores the electrostatic image developer according to the present embodiment and has a developing mechanism is suitable for use.

[0204] An example of the image forming apparatus according to the present embodiment is shown below, but is not limited thereto. In the following description, main parts shown in the drawings are described, and other descriptions are omitted.

[0205] Figure 1 FIG. is a schematic configuration diagram showing the image forming apparatus according to the present embodiment.

[0206] Figure 1 The shown image forming apparatus includes electrophotographic first to fourth image forming units 10Y, 10M, 10C, and 10K (image forming mechanisms) that output respective color images of yellow (Y), magenta (M), cyan (C), and black (K) based on color separation image data. These image forming units (hereinafter sometimes simply referred to as “units”) 10Y, 10M, 10C, and 10K are arranged side by side at a preset distance from each other in the horizontal direction. These units 10Y, 10M, 10C, and 10K may be processing cartridges that can be loaded and unloaded in the image forming apparatus.

[0207] Above each of the units 10Y, 10M, 10C, and 10K, an intermediate transfer belt (an example of an intermediate transfer member) 20 is provided to extend through each unit. The intermediate transfer belt 20 is wound around a driving roller 22 and a support roller 24 and is caused to run in the direction from the first unit 10Y toward the fourth unit 10K. The support roller 24 is biased in a direction separating from the driving roller 22 by a spring or the like (not shown), and a tension is applied to the intermediate transfer belt 20 wound around the two rollers. An intermediate transfer member cleaning device 30 opposed to the driving roller 22 is provided on the image holding body side of the intermediate transfer belt 20.

[0208] Yellow, magenta, cyan, and black toners stored in toner cartridges 8Y, 8M, 8C, and 8K are respectively supplied to developing devices (an example of a developing mechanism) 4Y, 4M, 4C, and 4K of each of the units 10Y, 10M, 10C, and 10K.

[0209] Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration and operation, the first unit 10Y that forms a yellow image and is disposed on the upstream side in the running direction of the intermediate transfer belt will be described as a representative here.

[0210] The first unit 10Y has a photoreceptor 1Y that functions as an image holding body. 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 exposes the charged surface based on a color separation image signal using a laser beam 3Y to form an electrostatic image, a developing device (an example of a developing mechanism) 4Y that supplies 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 toner remaining on the surface of the photoreceptor 1Y after primary transfer are sequentially arranged.

[0211] 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 transferring the toner image and removes the toner remaining on the surface of the photoreceptor 1Y.

[0212] The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20 and is provided at a position opposed to the photoreceptor 1Y. The primary transfer rollers 5Y, 5M, 5C, and 5K of each unit are respectively connected to a bias power source (not shown) that applies a primary transfer bias. Each bias power source changes the value of the transfer bias applied to each primary transfer roller under the control of a control unit (not shown).

[0213] The operation of forming a yellow image in the first unit 10Y will be described below.

[0214] First, before the operation, the surface of the photoreceptor 1Y is charged to a potential of -600V to -800V by the charging roller 2Y.

[0215] The photoreceptor 1Y is formed by laminating a photosensitive layer on a substrate having conductivity (for example, a volume resistivity of 1×10 -6 Ωcm or less at 20°C). This photosensitive layer usually has a high resistance (the resistance of a common resin), but has the property that the resistivity of the portion irradiated with the laser beam changes when irradiated with the laser beam. Therefore, according to the yellow image data sent from a control unit (not shown), the laser beam 3Y is irradiated onto the surface of the charged photoreceptor 1Y by the exposure device 3. Thus, an electrostatic image of a yellow image pattern is formed on the surface of the photoreceptor 1Y.

[0216] The electrostatic image is an image formed on the surface of the photoreceptor 1Y by charging, which is a so-called negative latent image. This negative latent image is formed as follows: the resistivity of the irradiated portion of the photosensitive layer is reduced by the laser beam 3Y, causing the charged charges on the surface of the photoreceptor 1Y to flow; on the other hand, the charges in the portion not irradiated with the laser beam 3Y remain, thereby forming this negative latent image.

[0217] The electrostatic image formed on the photoreceptor 1Y rotates to a preset development position as the photoreceptor 1Y rotates. And at this development position, the electrostatic image on the photoreceptor 1Y is developed into a toner image by the developing device 4Y for visualization.

[0218] Stored in the developing device 4Y is an electrostatic image developer containing, for example, at least yellow toner and a carrier. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, has a charge of the same polarity (negative polarity) as the charging charge 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 electrostatically adheres to the discharged latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed using the yellow toner. The photoreceptor 1Y on which the yellow toner image is formed continues to rotate at a preset speed, and the toner image developed on the photoreceptor 1Y is transferred to a preset primary transfer position.

[0219] When the yellow toner image on the photoreceptor 1Y is transferred to the primary transfer position, a primary transfer bias is applied to the primary transfer roller 5Y, and an electrostatic force from the photoreceptor 1Y toward the primary transfer roller 5Y acts on the toner image, transferring the toner image on the photoreceptor 1Y 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 unit (not shown) in the first unit 10Y.

[0220] The photoreceptor 1Y continues to rotate after the transfer of the toner image and comes into contact with the cleaning blade provided in the photoreceptor cleaning device 6Y. The toner remaining on the photoreceptor 1Y is removed by the photoreceptor cleaning device 6Y and recycled.

[0221] 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.

[0222] In this way, the intermediate transfer belt 20 onto 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, and the toner images of each color are multi-transferred in a superimposed manner.

[0223] The intermediate transfer belt 20 onto which the four-color toner image has been multi-transferred through the first to fourth units reaches the secondary transfer section, which is composed of the intermediate transfer belt 20, a support roller 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roller (an example of a secondary transfer mechanism) 26 disposed on the image holding surface side of the intermediate transfer belt 20. On the other hand, the recording paper (an example of a recording medium) P is sent to the gap where the secondary transfer roller 26 contacts the intermediate transfer belt 20 by a supply 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 an electrostatic force acting from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, transferring the toner image on the intermediate transfer belt 20 onto the recording paper P. The secondary transfer bias at this time is determined based on the resistance detected by a resistance detection mechanism (not shown) that detects the resistance of the secondary transfer section and is controlled in terms of voltage.

[0224] After that, the recording paper P is sent into the crimping section (biting section) of a pair of fixing rollers in the 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.

[0225] As the recording paper P for transferring the toner image, for example, ordinary paper used in electrophotographic copiers, printers, etc. can be cited. As the recording medium, in addition to the recording paper P, OHP transparent film, etc. can also be cited.

[0226] In order to further improve the smoothness of the surface of the fixed image, it is preferable that the surface of the recording paper P is also smooth. For example, coated paper obtained by coating the surface of ordinary paper with resin or the like, art paper for printing, etc. are suitable for use.

[0227] The recording paper P on which the color image has been fixed is sent to the discharge section, ending a series of color imaging operations.

[0228] <Processing cartridge, toner cartridge>

[0229] The processing cartridge of the present embodiment is a processing cartridge that can be loaded and unloaded in an image forming apparatus, and includes: an image holding member; a developing mechanism that stores the electrostatic image developer of the present embodiment and develops the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer; and a cleaning mechanism that has a blade in contact with the surface of the image holding member, and uses the blade to clean the toner remaining on the surface of the image holding member after the transfer of the toner image.

[0230] The processing cartridge of the present embodiment is not limited to the above configuration, and may also be a configuration that includes a developing mechanism and at least one of other mechanisms such as a charging mechanism, an electrostatic image forming mechanism, and a transfer mechanism, etc. when necessary.

[0231] An example of the processing cartridge of the present embodiment is shown below, but it is not limited thereto. In the following description, the main parts shown in the drawings will be described, and the description of other parts will be omitted.

[0232] Figure 2 It is a schematic configuration diagram showing the processing cartridge of the present embodiment.

[0233] Figure 2 The shown processing cartridge 200 is formed, for example, by integrally combining and holding a photosensitive member 107 (an example of an image holding member) and a charging roller 108 (an example of a charging mechanism), a developing device 111 (an example of a developing mechanism), and a photosensitive member cleaning device 113 (an example of a cleaning mechanism) provided around the photosensitive member 107 using a housing 117 having a mounting rail 116 and an opening 118 for exposure to form an ink cartridge. The photosensitive member cleaning device 113 has a blade in contact with the photosensitive member 107.

[0234] Figure 2 Among them, 109 represents an exposure device (an example of an electrostatic image forming mechanism), 112 represents a transfer device (an example of a transfer mechanism), 115 represents a fixing device (an example of a fixing mechanism), and 300 represents a recording paper (an example of a recording medium).

[0235] Next, the toner cartridge of the present embodiment will be described.

[0236] The toner cartridge of the present embodiment is a toner cartridge that stores the toner of the present embodiment and can be loaded and unloaded in an image forming apparatus. The toner cartridge stores replenishing toner for supplying to a developing mechanism provided in the image forming apparatus.

[0237] Figure 1The image forming apparatus shown has a configuration in which toner cartridges 8Y, 8M, 8C, and 8K are detachable, and the developing devices 4Y, 4M, 4C, and 4K are connected to the toner cartridges corresponding to each developing device (color) by toner supply tubes (not shown). When the toner stored in the toner cartridge is insufficient, the toner cartridge is replaced.

[0238] [Embodiment]

[0239] The embodiments of the present invention will be described in detail below with reference to embodiments, but the embodiments of the present invention are not limited to these embodiments. In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0240] [Production of Toner Particles]

[0241] [Production of Amorphous Polyester Resin Dispersion (A1)]

[0242] · Terephthalic acid: 70 parts

[0243] · Fumaric acid: 30 parts

[0244] · Ethylene glycol: 44 parts

[0245] · 1,5-Pentanediol: 46 parts

[0246] The above materials were put into a flask equipped with a stirring device, a nitrogen inlet tube, a temperature sensor, and a rectifying column. The temperature was raised to 210 °C in 1 hour under a nitrogen stream, and 1 part of tetraethoxy titanium was added to 100 parts in total of the above materials. While distilling off the generated water, the temperature was raised to 240 °C in 0.5 hour, and after continuing the dehydration condensation reaction at 240 °C for 1 hour, the reaction product was cooled. Thus, an amorphous polyester resin having a weight average molecular weight of 94500 and a glass transition temperature of 61 °C was obtained.

[0247] After putting 40 parts of ethyl acetate and 25 parts of 2-butanol into a container equipped with a temperature adjusting mechanism and a nitrogen replacement mechanism to prepare a mixed solvent, 100 parts of the amorphous polyester resin was slowly added and dissolved therein. 10% aqueous ammonia solution (an amount equivalent to 3 times the molar ratio of the acid value of the resin) was added thereto and stirred for 30 minutes. Then, the inside of the container was replaced with dry nitrogen, the temperature was maintained at 40 °C, and 400 parts of ion-exchanged water was added dropwise while stirring the mixed solution to perform emulsification. After the addition was completed, the emulsion was returned to 25 °C to obtain a resin particle dispersion in which resin particles having a volume average particle diameter of 210 nm were dispersed. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20% to prepare an amorphous polyester resin dispersion (A1).

[0248] [Production of Crystalline Polyester Resin Dispersion (B1)]

[0249] · Dimethyl sebacate: 97 parts

[0250] · Sodium dimethyl isophthalate-5-sulfonate: 3 parts

[0251] · Ethylene glycol: 100 parts

[0252] · Dibutyltin oxide (catalyst): 0.3 part

[0253] Add the above materials to a dried three-necked flask under heating, displace the air in the three-necked flask with nitrogen to form an inert atmosphere, and carry out stirring reflux at 180 °C for 5 hours using mechanical stirring. Then, slowly raise the temperature to 240 °C under reduced pressure and stir for 2 hours. After it becomes viscous, carry out air cooling 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 is obtained.

[0254] Mix 90 parts of the crystalline polyester resin, 1.8 parts of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., NEOGEN RK), and 210 parts of ion-exchanged water, heat to 100 °C, disperse using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA), and then carry out dispersion treatment for 1 hour using a pressure discharge type Gaulin homogenizer to obtain a resin particle dispersion liquid in which resin particles with a volume average particle diameter of 205 nm are dispersed. Add ion-exchanged water to this resin particle dispersion liquid to adjust the solid content to 20% to form a crystalline polyester resin dispersion liquid (B1).

[0255] [Preparation of release agent particle dispersion liquid (W1)]

[0256] · Solid paraffin (HNP-9 manufactured by Nippon Seiro Co., Ltd.): 100 parts

[0257] · Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., NEOGEN RK): 1 part

[0258] · Ion-exchanged water: 350 parts

[0259] Mix the above materials and heat to 100 °C, disperse using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA), and then carry out dispersion treatment using a pressure discharge type Gaulin homogenizer to obtain a release agent particle dispersion liquid in which release agent particles with a volume average particle diameter of 200 nm are dispersed. Add ion-exchanged water to this release agent particle dispersion liquid to adjust the solid content to 20% to form a release agent particle dispersion liquid (W1).

[0260] [Preparation of colorant particle dispersion liquid (K1)]

[0261] Carbon black (manufactured by Cabot Corporation, Regal 330): 50 parts

[0262] · Ionic surfactant NEOGEN RK (Daiichi Kogyo Seiyaku Co., Ltd.): 5 parts

[0263] · Ion-exchanged water: 195 parts

[0264] Mix the above materials and disperse them for 10 minutes at 240 MPa using an Ultimaizer (manufactured by Sugino Machine Limited) to obtain a dispersion liquid (K1) of coloring agent particles with a solid content of 20%.

[0265] [Preparation of toner particles]

[0266] · Ion-exchanged water: 200 parts

[0267] · Amorphous polyester resin dispersion liquid (A1): 150 parts

[0268] · Crystalline polyester resin dispersion liquid (B1): 10 parts

[0269] · Release agent particle dispersion liquid (W1): 10 parts

[0270] · Coloring agent particle dispersion liquid (K1): 15 parts

[0271] · Anionic surfactant (Tayca Power): 2.8 parts

[0272] Put the above materials into a round stainless-steel flask, add 0.1N nitric acid to adjust the pH to 3.5, and then add an aqueous solution of polyaluminum chloride (manufactured by Oji Paper Co., Ltd., 30% powder) obtained by dissolving 2 parts of polyaluminum chloride in 30 parts of ion-exchanged water. After dispersing at 30°C using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA), heat it to 45°C in a heating oil bath and maintain until the volume average particle size reaches 4.9 μm. Then, add 60 parts of the amorphous polyester resin dispersion (A1) and maintain for 30 minutes. Then, after the volume average particle size reaches 5.2 μm, further add 60 parts of the amorphous polyester resin dispersion (A1) and maintain for 30 minutes. Then, add 20 parts of a 10% aqueous solution of NTA (nitrilotriacetic acid) metal salt (Chelest 70, manufactured by Chelest Co., Ltd.), and add 1N sodium hydroxide aqueous solution to adjust the pH to 9.0. Next, add 1 part of an anionic surfactant (TaycaPower), heat to 85°C while continuing stirring, and maintain for 5 hours. Then, cool to 20°C at a rate of 20°C / minute. Then, filter, wash thoroughly with ion-exchanged water, and dry to obtain toner particles (1) with a volume average particle size of 5.7 μm and an average roundness of 0.971.

[0273] <Production of layered structure compound particles>

[0274] [Production of melamine cyanurate particles]

[0275] Crush and classify a commercially available melamine cyanurate (manufactured by Nissan Chemical Industries, Ltd., MC-4500) using a jet mill to obtain the following melamine cyanurate particles (1) to (5). "MC" in Table 1 refers to melamine cyanurate.

[0276] · Melamine cyanurate particle (1): Volume average particle size 1.0 μm

[0277] · Melamine cyanurate particle (2): Volume average particle size 3.5 μm

[0278] · Melamine cyanurate particle (3): Volume average particle size 2.9 μm

[0279] · Melamine cyanurate particle (4): Volume average particle size 0.4 μm

[0280] · Melamine cyanurate particle (5): Volume average particle size 0.2 μm

[0281] [Preparation of boron nitride particles]

[0282] Prepare commercially available boron nitride particles (manufactured by MARUKA, AP-10S). The volume average particle size is 2.4 μm. "BN" in Table 1 refers to boron nitride.

[0283] <Production of oil-treated particles>

[0284] [Production of silicone oil-treated silica particles (1)]

[0285] Mix SiCl4, hydrogen, and oxygen in the mixing chamber of a burner and burn them at a temperature of 1000 °C or higher and 3000 °C or lower to obtain silica powder from the burned gas and obtain silica particles (1). At this time, by setting the molar ratio of hydrogen to oxygen to 1.38:1, the volume average particle size (D50v) of the produced silica particles (1) is adjusted to 65 nm.

[0286] Put 100 parts of silica particles (1) and 500 parts of ethanol into an evaporator and stir for 15 minutes while maintaining the temperature at 40 °C. Then, add 15 parts of dimethyl silicone oil and stir for 15 minutes, and further add 15 parts of dimethyl silicone oil and stir for 15 minutes. Then, raise the temperature to 90 °C, dry the ethanol under reduced pressure, and further dry it in a vacuum at 120 °C for 30 minutes. Thus, silicone oil-treated silica particles (1) with a volume average particle size of 65 nm and a free oil content of 1.5% are obtained.

[0287] [Production of silicone oil-treated silica particles (2)]

[0288] Change the first amount of dimethyl silicone oil to 20 parts and the second amount to 30 parts, and obtain silicone oil-treated silica particles (2) with a volume average particle size of 65 nm and a free oil content of 6.0% in the same manner as the production of silicone oil-treated silica particles (1).

[0289] [Production of silicone oil-treated silica particles (3)]

[0290] Change the first amount of dimethyl silicone oil to 20 parts and the second amount to 25 parts, and obtain silicone oil-treated silica particles (3) with a volume average particle size of 65 nm and a free oil content of 5.0% in the same manner as the production of silicone oil-treated silica particles (1).

[0291] [Production of silicone oil-treated silica particles (4)]

[0292] Change the first amount of dimethyl silicone oil to 20 parts and the second amount to 22 parts, and obtain silicone oil-treated silica particles (4) with a volume average particle size of 65 nm and a free oil content of 4.4% in the same manner as the production of silicone oil-treated silica particles (1).

[0293] [Production of silicone oil-treated silica particles (5)]

[0294] The amount of dimethyl silicone oil for the first time was changed to 20 parts, and the amount for the second time was changed to 20 parts. In the same manner as the production of silicone oil-treated silica particles (1), silicone oil-treated silica particles (5) with a volume average particle diameter of 65 nm and a free oil content of 2.5% were obtained.

[0295] [Production of silicone oil-treated silica particles (6)]

[0296] The amount of dimethyl silicone oil for the first time was changed to 15 parts, and the amount for the second time was changed to 20 parts. In the same manner as the production of silicone oil-treated silica particles (1), silicone oil-treated silica particles (6) with a volume average particle diameter of 65 nm and a free oil content of 2.0% were obtained.

[0297] [Production of silicone oil-treated silica particles (7)]

[0298] The amount of dimethyl silicone oil for the first time was changed to 10 parts, and the amount for the second time was changed to 10 parts. In the same manner as the production of silicone oil-treated silica particles (1), silicone oil-treated silica particles (7) with a volume average particle diameter of 65 nm and a free oil content of 1.25% were obtained.

[0299] [Production of silicone oil-treated silica particles (8)]

[0300] The amount of dimethyl silicone oil for the first time was changed to 1 part, and the amount for the second time was changed to 1 part. In the same manner as the production of silicone oil-treated silica particles (1), silicone oil-treated silica particles (8) with a volume average particle diameter of 65 nm and a free oil content of 0.25% were obtained.

[0301] [Production of silicone oil-treated PMMA particles]

[0302] While stirring 100 parts of polymethyl methacrylate particles (PMMA particles, volume average particle diameter (D50v) 300 nm) and maintaining the temperature at 60 °C, a solution of 20 parts of dimethyl silicone oil (weight average molecular weight 12100, number average molecular weight 2030) - 20 parts of hexane was sprayed, and the solvent was dried while performing a stirring treatment. Then, it was heated to 300 °C under stirring and maintained at 300 °C for 1 hour, thereby obtaining silicone oil-treated PMMA particles with a volume average particle diameter of 300 nm and a free oil content of 1.5%.

[0303] [Production of the carrier]

[0304] After stirring 500 parts of spherical magnetite powder particles (volume average particle size 0.55 μm) using a Henschel mixer, 5 parts of a titanate coupling agent were added and the temperature was raised to 100 °C, followed by stirring 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. After reacting at 85 °C for 120 minutes with stirring, it was cooled to 25 °C. After adding 500 parts of water, 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.

[0305] <Example 1>

[0306] The toner particles (1), melamine cyanurate particles (1), and silicone oil-treated silica particles (1) were added to a sample mill in the content ratios described in Table 1 and mixed at 10,000 rpm for 30 seconds. Next, sieving was performed using a vibrating sieve with a mesh of 45 μm to prepare a toner with a volume average particle size of 5.7 μm. 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.

[0307] <Examples 2 - 9>

[0308] The addition amount of the melamine cyanurate particles (1) or the type and addition amount of the oil-treated particles were changed, and a toner and a developer were obtained in the same manner as in Example 1.

[0309] <Examples 10 - 15>

[0310] The type of the layered structure compound particles or the type of the oil-treated particles was changed, and a toner and a developer were obtained in the same manner as in Example 1.

[0311] <Comparative Examples 1 - 2>

[0312] The addition amount of the melamine cyanurate particles (1) and the type and addition amount of the oil-treated particles were changed, and a toner and a developer were obtained in the same manner as in Example 1.

[0313] <Performance Evaluation>

[0314] [Color streaks generated during continuous imaging in a low-temperature and low-humidity environment (color streaks caused by toner leakage)]

[0315] Using a modified 700 Digital Color Press manufactured by Fuji Xerox Co., Ltd. in an environment with a temperature of 10°C and a relative humidity of 10%, output 100,000 images with an image density of 0.2% on A4-sized paper. Then, output 500 image charts on A4-sized paper, which are composed of solid images and halftone images with a toner loading of 0.1 mg / cm 2 combined. Visually observe the 10th, 50th, 100th, and 500th sheets, and grade the total number of color streaks generated in the halftone images according to the following criteria.

[0316] G1: 0 streaks

[0317] G2: 1 streak

[0318] G3: 2 to 5 streaks. Allowable range.

[0319] G4: More than 6 streaks. Not allowable in practice.

[0320] [Color streaks generated during continuous imaging in a high-temperature and high-humidity environment (color streaks caused by wear of the cleaning blade)]

[0321] Using a modified 700 Digital Color Press manufactured by Fuji Xerox Co., Ltd. in an environment with a temperature of 28°C and a relative humidity of 85%, output 100,000 images with an image density of 0.2%. Then, output 1 image chart on A4-sized paper, which is composed of solid images and halftone images with a toner loading of 0.1 mg / cm 2 combined. Visually observe the halftone image, and observe the contact part of the cleaning blade under a microscope (manufactured by KEYENCE Corporation, VH6200) magnified 100 times. Grade the number of color streaks generated in the halftone image and the state of the contact part of the cleaning blade according to the following criteria.

[0322] G1: 0 color streaks and no notch on the cleaning blade.

[0323] G2: 0 color streaks and a notch on the cleaning blade.

[0324] G3: 1 to 5 color streaks and a notch on the cleaning blade. Allowable range.

[0325] G4: More than 6 color streaks and a notch on the cleaning blade. Not allowable in practice.

[0326]

Claims

1. A toner for electrostatic image development, The toner contains toner particles, melamine cyanurate particles, oil-treated particles, and free oil, wherein, The free oil is the oil added to the above-mentioned toner for electrostatic image development or the oil freed from the above-mentioned oil-treated particles, Relative to the entire above-mentioned toner for electrostatic image development, the content of the free oil is 0.005% by mass or more and 0.2% by mass or less, The mass-based ratio Ma / Mb of the content Ma of the above-mentioned melamine cyanurate particles to the content Mb of the free oil is 0.05 or more and 100 or less, The mass-based ratio Mc / Ma of the content Mc of the above-mentioned oil-treated particles to the content Ma of the above-mentioned melamine cyanurate particles is 0.5 or more and 400 or less.

2. The toner for electrostatic image development according to claim 1, wherein, The volume average particle diameter of the above-mentioned melamine cyanurate particles is 0.4 μm or more and less than 3.0 μm.

3. The toner for electrostatic image development according to claim 1, wherein, The mass-based ratio Ma / Mb of the content Ma of the above-mentioned melamine cyanurate particles to the content Mb of the free oil is 0.2 or more and 100 or less.

4. The toner for electrostatic image development according to claim 1, wherein, Relative to the entire above-mentioned toner for electrostatic image development, the content of the free oil is 0.01% by mass or more and 0.12% by mass or less.

5. The toner for electrostatic image development according to claim 2, wherein, The volume average particle diameter of the above-mentioned melamine cyanurate particles is 0.5 μm or more and 2.5 μm or less.

6. The toner for electrostatic image development according to claim 1, wherein, The above-mentioned oil-treated particles include oil-treated silica particles.

7. The toner for electrostatic image development according to claim 1, wherein, The mass-based ratio Mc / Ma of the content Mc of the above-mentioned oil-treated particles to the content Ma of the above-mentioned melamine cyanurate particles is 0.5 or more and 200 or less.

8. An electrostatic image developer, which contains the toner for electrostatic image development according to any one of claims 1 to 7.

9. A toner cartridge that can be loaded and unloaded in an image forming apparatus, which stores the toner for electrostatic image development according to any one of claims 1 to 7.

10. A process cartridge that can be loaded and unloaded in an image forming apparatus, which includes: An image holding member; A developing mechanism that stores the electrostatic image developer according to claim 8 and develops the electrostatic image formed on the surface of the above-mentioned image holding member into a toner image; and A cleaning mechanism that has a blade in contact with the surface of the above-mentioned image holding member and uses the blade to clean the toner remaining on the surface of the above-mentioned image holding member after the transfer of the toner image.

11. An image forming apparatus, which includes: An image holding member; A charging mechanism that charges the surface of the above-mentioned image holding member; An electrostatic image forming mechanism that forms an electrostatic image on the surface of the charged above-mentioned image holding member; A developing mechanism that stores the electrostatic image developer according to claim 8 and develops the electrostatic image formed on the surface of the above-mentioned image holding member into a toner image; A transfer mechanism that transfers the toner image formed on the surface of the above-mentioned image holding member to the surface of a recording medium; A fixing mechanism that fixes the toner image transferred to the surface of the above-mentioned recording medium; and A cleaning mechanism that has a blade in contact with the surface of the above-mentioned image holding member and uses the blade to clean the toner remaining on the surface of the above-mentioned image holding member after the transfer of the toner image.

12. An image forming method, comprising the following steps: A charging step of charging the surface of an image carrier; An electrostatic image forming step of forming an electrostatic image on the charged surface of the image carrier; A developing step of developing the electrostatic image formed on the surface of the image carrier into a toner image by using the electrostatic image developer according to claim 8; A transferring step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium; A fixing step of fixing the toner image transferred to the surface of the recording medium; and A cleaning step of bringing a blade into contact with the surface of the image carrier after transferring the toner image, and cleaning the toner remaining on the surface of the image carrier.

Images