Toner for electrostatic image development, electrostatic image developer and toner cartridge

Abstract

The present invention provides a toner for electrostatic image development, an electrostatic image developer, and a toner box, which are excellent in color streak suppression at one end portion in the width direction of an image retaining body even when low image density printing is continuously performed after being placed in a high temperature and high humidity environment. The toner for electrostatic image development includes toner master particles and an external additive. The toner master particles contain at least a nonionic surfactant, a binder resin, and a release agent, wherein the content of the nonionic surfactant is 0.05 mass % or more and 1 mass % or less relative to the total mass of the toner, and the external additive contains tin oxide particles.

Description

Technical Field

[0001] The present invention relates to a toner for developing electrostatic charge images, an electrostatic charge image developer and a toner box. Background Art

[0002] Methods such as electrophotography that visualize image information via electrostatic charge images are currently used in various fields.

[0003] In the past, in electronic photography, a method generally used to make it visible is to use the following multiple steps: various components are used to form an electrostatic latent image on a photoreceptor or an electrostatic recording body, and charge-detecting particles called toner are attached to the electrostatic latent image to develop the electrostatic latent image (toner image), transfer it to the surface of the transfer body, and fix it by heating or the like.

[0004] In addition, as conventional toners or methods for producing the same, those described in Patent Documents 1 to 3 are known.

[0005] Patent document 1 discloses a method for manufacturing toner for electronic photography, comprising: a step of emulsifying a binder resin containing polyester in an aqueous medium in the presence of a nonionic surfactant to obtain resin particles (step 1); a step of agglomerating and / or unifying the resin emulsified particles obtained in the step 1 to obtain unified particles (step 2); a step of washing and solid-liquid separation of the unified particles to obtain toner particles (step 3); and a step of surface-treating the toner particles using an external additive containing negatively charged inorganic microparticles having a number average particle size of 0.005 μm to 0.05 μm and positively charged organic microparticles having a number average particle size of 0.1 μm to 0.6 μm to obtain toner (step 4).

[0006] Patent document 2 discloses a toner for electronic photography, which comprises a binder resin containing polyester, a nonionic surfactant and an external additive, wherein the content of the nonionic surfactant is 0.05 wt % to 0.5 wt %, and the external additive comprises negatively charged inorganic microparticles having a number average particle size of 0.005 μm to 0.05 μm, and positively charged organic microparticles having a number average particle size of 0.1 μm to 0.6 μm.

[0007] Patent document 3 discloses a toner for image formation, which is an image forming toner formed by adding inorganic microparticles to toner matrix particles containing at least a binding resin and a colorant, wherein the image forming toner is formed by attaching inorganic microparticles A having a coefficient of variation of volume distribution of particle size distribution of less than 50% to the toner matrix particles through wet treatment.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2012-63783

[0011] Patent Document 2: Japanese Patent Application Publication No. 2008-151950

[0012] Patent Document 3: Japanese Patent Application Publication No. 2005-266557 Summary of the invention

[0013] Problems to be solved by the invention

[0014] The problem to be solved by the present invention is to provide a toner for electrostatic charge image development as follows: compared with the case where the content of the nonionic surfactant is less than 0.05 mass % or exceeds 1 mass % relative to the total mass of the toner, or the external additive contains only silica particles, the color streak suppression property of one end portion of the image retaining body in the width direction is excellent even when low image density (1%) printing is continuously performed after being placed in a high temperature and high humidity environment (28°C and 85% RH).

[0015] Technical means of solving problems

[0016] Specific means for solving the above-mentioned problems include the following embodiments.

[0017] <1> A toner for electrostatic image development, comprising toner base particles and an external additive. The toner base particles contain at least a nonionic surfactant, a binder resin, and a release agent, the nonionic surfactant content is 0.05 mass % or more and 1 mass % or less relative to the total mass of the toner, and the external additive contains tin oxide particles.

[0018] <2> The electrostatic image developing toner according to <1>, wherein a content of the tin oxide particles is 0.1% by mass or more and 2.0% by mass or less based on the total mass of the toner.

[0019] <3> The electrostatic charge image developing toner according to <1> or <2>, wherein when the content of the nonionic surfactant in the toner is set to Wa and the content of the tin oxide particles is set to Wb, the value of Wa / (Wa+Wb) is greater than or equal to 0.024 and less than or equal to 0.90.

[0020] <4> The electrostatic charge image developing toner according to any one of <1> to <3>, wherein the toner base particles further contain a colorant.

[0021] <5> The electrostatic charge image developing toner according to any one of <1> to <4>, wherein the toner base particles further contain 5'-chloro-3-hydroxy-2'-methoxy-2-naphthylaniline.

[0022] <6> The electrostatic image developing toner according to <5>, wherein the content of the 5'-chloro-3-hydroxy-2'-methoxy-2-naphthylaniline is 1 ppm or more and 300 ppm or less based on the total mass of the toner.

[0023] <7> The electrostatic charge image developing toner according to any one of <1> to <6>, wherein the nonionic surfactant is a compound having a polyalkyleneoxy structure.

[0024] <8> The electrostatic image developing toner according to <7>, wherein the nonionic surfactant is a compound having a polyethyleneoxy structure.

[0025] <9> The electrostatic charge image developing toner according to any one of <1> to <7>, wherein the binder resin contains a crystalline resin.

[0026] <10> The electrostatic charge image developing toner according to any one of <1> to <8>, wherein the toner base particles are core-shell type particles.

[0027] <11> An electrostatic image developer comprising the electrostatic image developing toner according to any one of <1> to <10>.

[0028] <12> A toner cartridge that houses the electrostatic image developing toner according to any one of <1> to <10> and is detachably mountable in an image forming apparatus.

[0029] <13> A processing box that can be detachably installed in an image forming device, the processing box including a developing component that accommodates the electrostatic charge image developer according to <11>, and uses the electrostatic charge image developer to develop the electrostatic charge image formed on the surface of the image retaining body into a toner image.

[0030] <14> An image forming device, comprising: an image retaining body; a charging component for charging the surface of the image retaining body; an electrostatic charge image forming component for forming an electrostatic charge image on the charged surface of the image retaining body; a developing component for storing the electrostatic charge image developer according to <11> and developing the electrostatic charge image formed on the surface of the image retaining body into a toner image using the electrostatic charge image developer; a transferring component for transferring the toner image formed on the surface of the image retaining body to the surface of a recording medium; and a fixing component for fixing the toner image transferred to the surface of the recording medium.

[0031] <15> An image forming method, comprising: a charging step of charging the surface of an image retaining body; an electrostatic charge image forming step of forming an electrostatic charge image on the charged surface of the image retaining body; a developing step of developing the electrostatic charge image formed on the surface of the image retaining body into a toner image using the electrostatic charge image developer according to <11>; a transferring step of transferring the toner image formed on the surface of the image retaining body to the surface of a recording medium; and a fixing step of fixing the toner image transferred to the surface of the recording medium.

[0032] Effects of the Invention

[0033] According to the invention of <1> or <4>, the following electrostatic charge image developing toner is provided: compared with the case where the content of the nonionic surfactant is less than 0.05 mass % or exceeds 1 mass % relative to the total mass of the toner, or the external additive contains only silica particles, the color streak suppression property of one end portion of the image retaining body in the width direction is excellent even when low image density (1%) printing is continuously performed after being placed in a high temperature and high humidity environment (28°C and 85% RH).

[0034] According to the invention of <2>, the following electrostatic charge image developing toner is provided: compared with the case where the content of the tin oxide particles is less than 0.1 mass % or exceeds 2.0 mass % relative to the total mass of the toner, even when low image density printing is continuously performed after being placed in a high temperature and high humidity environment, the color streak suppression property of one end portion of the image retaining body in the width direction is better.

[0035] According to the invention of <3>, the following electrostatic charge image developing toner is provided: compared with the case where the content of the nonionic surfactant in the toner is set to Wa and the content of the tin oxide particles is set to Wb, and the value of Wa / (Wa+Wb) is less than 0.024 or exceeds 0.90, even when low image density printing is continuously performed after being placed in a high temperature and high humidity environment, the color streak suppression property of one end portion of the image retaining body in the width direction is better.

[0036] According to the invention of <5>, the following electrostatic charge image developing toner is provided: compared with the case where 5'-chloro-3-hydroxy-2'-methoxy-2-naphthylaniline is not contained, even when low image density printing is continuously performed after being placed in a high temperature and high humidity environment, the color streak suppression property of one end portion in the width direction of the image retaining body is better.

[0037] According to the invention of <6>, the following electrostatic charge image developing toner is provided: compared with the case where the content of the 5'-chloro-3-hydroxy-2'-methoxy-2-naphthylaniline relative to the total mass of the toner is less than 1 ppm or exceeds 300 ppm, even when low image density printing is continuously performed after being placed in a high temperature and high humidity environment, the color streak suppression property of one end portion of the image retaining body in the width direction is better.

[0038] According to the invention of <7>, the following electrostatic charge image developing toner is provided: compared with the case where the nonionic surfactant is a glycerol fatty acid ester compound, even when low image density printing is continuously performed after being placed in a high temperature and high humidity environment, the color streak suppression property of one end portion in the width direction of the image retaining body is better.

[0039] According to the invention of <8>, the following electrostatic charge image developing toner is provided: compared with the case where the nonionic surfactant is a compound having only a polypropylene oxide structure as a polyalkylene oxide structure, the color streak suppression property of one end portion in the width direction of the image retaining body is better even when low image density printing is continuously performed after being placed in a high temperature and high humidity environment.

[0040] According to the invention of <9>, the following electrostatic charge image developing toner is provided: compared with the case where the binding resin only contains a non-crystalline resin, even when low image density printing is continuously performed after being placed in a high temperature and high humidity environment, the color streak suppression property of one end portion in the width direction of the image retaining body is better.

[0041] According to the invention of <10>, the following electrostatic charge image developing toner is provided: compared with the case where the toner base particles are particles without a shell structure, even when low image density printing is continuously performed after being placed in a high temperature and high humidity environment, the color streak suppression property of one end portion in the width direction of the image retaining body is better.

[0042] According to the inventions of <11> to <15>, the following electrostatic charge image developer, toner box, processing box, image forming device or image forming method is provided: compared with the case where the content of nonionic surfactant in the toner is less than 0.05 mass% or exceeds 1 mass% relative to the total mass of the toner, or the external additive contains only silica particles, the color streak suppression property of one end portion of the image retaining body in the width direction is excellent even when low image density printing is continuously performed after being placed in a high temperature and high humidity environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a diagram schematically showing the configuration of the image forming apparatus according to the present embodiment.

[0044] Figure 2 It is a diagram schematically showing the configuration of a process cartridge according to the present embodiment.

[0045] Explanation of symbols

[0046] 1Y, 1M, 1C, 1K: Photoreceptor (an example of an image holding body)

[0047] 2Y, 2M, 2C, 2K: Charging roller (an example of a charging member)

[0048] 3: Exposure device (an example of electrostatic charge image forming member)

[0049] 3Y, 3M, 3C, 3K: Laser light

[0050] 4Y, 4M, 4C, 4K: Development device (an example of a development unit)

[0051] 5Y, 5M, 5C, 5K: primary transfer rollers (an example of primary transfer members)

[0052] 6Y, 6M, 6C, 6K: Photosensitive body cleaning device (an example of an image holding body cleaning member)

[0053] 8Y, 8M, 8C, 8K: Toner cartridge

[0054] 10Y, 10M, 10C, 10K: Image forming unit

[0055] 20: Intermediate transfer belt (an example of an intermediate transfer body)

[0056] 22: Driving roller

[0057] 24: Support roller

[0058] 26: Secondary transfer roller (an example of a secondary transfer member)

[0059] 28: Fixing device (an example of a fixing part)

[0060] 30: Intermediate transfer belt cleaning device (an example of an intermediate transfer body cleaning component)

[0061] P: Recording paper (an example of recording medium)

[0062] 107: Photoreceptor (an example of an image holding member)

[0063] 108: Charging roller (an example of a charging component)

[0064] 109: Exposure device (an example of electrostatic charge image forming member)

[0065] 111: Development device (an example of a development unit)

[0066] 112: Transfer device (an example of a transfer member)

[0067] 113: Photosensitive body cleaning device (an example of a photosensitive body cleaning member)

[0068] 115: Fixing device (an example of a fixing member)

[0069] 116: Install the rails

[0070] 117: Frame

[0071] 118: Opening for exposure

[0072] 200: Processing box

[0073] 300: Recording paper (an example of recording medium) DETAILED DESCRIPTION

[0074] When the amount of each component in the composition is mentioned in the present specification, when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified, the amount refers to the total amount of the plurality of substances present in the composition.

[0075] In this specification, “toner for developing electrostatic charge image” is also simply referred to as “toner”, and “electrostatic charge image developer” is also simply referred to as “developer”.

[0076] Hereinafter, an embodiment as an example of the present invention will be described.

[0077] <Toner for electrostatic image development>

[0078] The electrostatic charge image developing toner of this embodiment comprises a toner base particle containing at least a nonionic surfactant, a binder resin and a release agent, and an external additive, wherein the content of the nonionic surfactant is greater than 0.05% by mass and less than 1% by mass relative to the total mass of the toner, and the external additive comprises tin oxide particles.

[0079] It is believed that the discharge products can be removed and suppressed by using tin oxide particles as abrasives to act on the color stripes generated by the discharge products adhering to the surface of the image holder. Since tin oxide has low polarity and is difficult to be charged, its electrostatic adhesion is small. In addition to the developing electric field, tin oxide is also supplied to the image holder by the centrifugal force of the toner supply components such as the magnetic roller. Therefore, the difference in the supply amount between the image part and the non-image part is small, and color stripes can be suppressed in both the image part and the non-image part. However, in a high temperature and high humidity environment, tin oxide is difficult to be charged. Therefore, it is supplied only by the centrifugal force of the magnetic roller. In the case of printing with a low image density and a small continuous toner supply, there is the following problem: the toner supply component is preferentially supplied at the position close to the toner supply port of the developer, and the tin oxide particles are not supplied to the developing part far from the toner supply port, that is, the end portion of the image holder in the width direction (axial direction), resulting in color stripes.

[0080] The electrostatic charge image developing toner of the present embodiment has excellent color streak suppression (hereinafter also referred to as "color streak suppression") at one end portion in the width direction of the image retaining body, even when the image is continuously printed at a low image density after being placed in a high temperature and high humidity environment. The reason for this is not certain, but it is presumed to be due to the following reasons.

[0081] By including tin oxide particles as an external additive and including a nonionic surfactant in the toner base particles within the above-mentioned range, the nonionic surfactant is adsorbed around the various materials constituting the toner when the toner is produced, thereby maintaining the dispersibility of the various materials. The deviation of the toner constituent components in the obtained toner is reduced, and the charge difference between the various parts of the toner surface is small. The tin oxide particles are appropriately charged and move together with the toner by utilizing electrostatic adhesion, thereby being supplied to the image retaining body even in the developing section away from the toner supply port. Even in the case of continuous low image density printing after being placed in a high temperature and high humidity environment, the color stripe suppression property of one end portion of the image retaining body in the width direction is excellent.

[0082] Hereinafter, the electrostatic image developing toner according to the present embodiment will be described in detail.

[0083] The toner of the present embodiment includes toner base particles (also referred to as "toner particles") and, if necessary, external additives.

[0084] (External additives)

[0085] The electrostatic image developing toner according to the present embodiment has an external additive including tin oxide particles.

[0086] From the viewpoint of color streak suppression, the number average particle size of the tin oxide particles is preferably 0.01 μm or more and 10 μm or less, more preferably 0.02 μm or more and 8 μm or less, and particularly preferably 0.05 μm or more and 5 μm or less.

[0087] The method for determining the number average particle size of the external additive in the present embodiment is to observe and take an image using a scanning electron microscope (S-4100 manufactured by Hitachi, Ltd.). The taken image is imported into an image analysis device (manufactured by Nireco (stock), LUZEXIII), and the area of ​​each particle is obtained by image analysis, and the circle equivalent diameter (nm) is obtained based on the area. The 50% diameter (D50p) of the cumulative frequency of the number basis of the circle equivalent diameter of more than 100 particles is set as the number average particle size.

[0088] The surface of the tin oxide particles may be subjected to a hydrophobic treatment. The hydrophobic treatment is performed, for example, by immersing the inorganic particles in a hydrophobic treatment agent. The hydrophobic treatment agent is not particularly limited, and examples thereof include: a silane coupling agent, silicone oil, a titanate coupling agent, an aluminum coupling agent, etc. These may be used alone or in combination of two or more.

[0089] From the viewpoint of color streak suppression, the content of the tin oxide particles is preferably from 0.01 mass % to 10 mass %, more preferably from 0.05 mass % to 5 mass %, further preferably from 0.1 mass % to 2.0 mass %, particularly preferably from 0.2 mass % to 1.8 mass %, and most preferably from 0.6 mass % to 1.5 mass %, relative to the total mass of the toner.

[0090] Furthermore, the electrostatic image developing toner of the present embodiment may contain an external additive other than the tin oxide particles.

[0091] As other external additives, for example, inorganic particles other than the above-mentioned external additives can be listed. As materials of other external additives, there can be listed: SiO2, TiO2, Al2O3, CuO, ZnO, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2) n , Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, etc.

[0092] The surface of the inorganic particles as other external additives can be subjected to hydrophobic treatment. The hydrophobic treatment is performed by, for example, immersing the inorganic particles in a hydrophobic treatment agent. The hydrophobic treatment agent is not particularly limited, and examples thereof include: silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents, etc. These can be used alone or in combination of two or more.

[0093] The amount of the hydrophobizing agent is preferably 1 part by mass or more and 10 parts by mass or less relative to 100 parts by mass of the inorganic particles.

[0094] Other external additives include resin particles (polystyrene, polymethyl methacrylate (PMMA), melamine resin, etc.), cleaning activators (for example, metal salts of higher fatty acids represented by zinc stearate, and particles of fluorine-based high molecular weight bodies), etc.

[0095] The content of other external additives is, for example, preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.01% by mass or more and 2.0% by mass or less, based on the total mass of the toner.

[0096] In addition, from the viewpoint of color streak suppression, the content of other external additives is preferably smaller than the content of the tin oxide particles.

[0097] (Toner Masterbatch)

[0098] The toner base particles contain, for example, a nonionic surfactant, a binder resin, a release agent, a colorant as required, and other additives, and preferably contain a nonionic surfactant, a binder resin, a colorant, and a release agent.

[0099] -Nonionic surfactant-

[0100] The toner base particles contain a nonionic surfactant, and the content of the nonionic surfactant is 0.05 mass % or more and 1 mass % or less relative to the total mass of the toner.

[0101] The nonionic surfactant is not particularly limited, and known nonionic surfactants can be used. Specifically, for example, polyoxyethylene alkyl ethers, polyoxyethylene aryl ethers, glycerol fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol fatty acid partial esters, propylene glycol monofatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerol fatty acid partial esters, polyoxyethylene glycerol fatty acid partial esters, fatty acid diethanolamides, N,N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, trialkylamine oxides, etc. can be cited.

[0102] In addition, examples of the nonionic surfactant include silicone-based surfactants and fluorine-based surfactants.

[0103] Among these, from the viewpoint of color streak suppression, the nonionic surfactant is preferably a compound having a polyalkyleneoxy structure, more preferably a compound having a polyethyleneoxy structure, further preferably a polyoxyethylene alkyl ether compound, or a polyoxyethylene aryl ether compound, particularly preferably a polyoxyethylene lauryl ether compound, or a polyoxyethylene distyrenated phenyl ether compound.

[0104] In addition, as the nonionic surfactant, from the viewpoint of color streak suppression, a polyoxyethylene (average addition mole number: 10 mol or more and 60 mol or less) alkyl (carbon number 8 or more and 18 or less) ether compound is preferred, and more preferably, a polyoxyethylene alkyl ether compound in which the carbon number of the alkyl group is 12 or more and 18 or less and the average addition mole number is 12 or more and 18 or less can be cited. As the nonionic surfactant, specifically, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, or polyoxyethylene lauryl ether is particularly preferred.

[0105] Moreover, as a nonionic surfactant, a commercially available item can also be used.

[0106] Examples of commercially available products include emulgen 150, emulgen A-60, and emulgen A-90 (all manufactured by Kao Corporation).

[0107] The toner base particles may contain one type of nonionic surfactant alone or two or more types thereof.

[0108] The content of the nonionic surfactant is greater than 0.05 mass % and less than 1 mass % relative to the total mass of the toner. From the viewpoint of color streak suppression, it is preferably greater than 0.08 mass % and less than 0.95 mass %, more preferably greater than 0.5 mass % and less than 0.95 mass %, further preferably greater than 0.7 mass % and less than 0.95 mass %, and particularly preferably greater than 0.8 mass % and less than 0.95 mass %.

[0109] In addition, among the nonionic surfactants contained in the electrostatic charge image developing toner of the present embodiment, preferably 50% by mass or more of the compound having a polyalkylene oxide structure, more preferably 80% by mass or more of the compound having a polyalkylene oxide structure, further preferably 90% by mass or more of the compound having a polyalkylene oxide structure, and particularly preferably 100% by mass of the compound having a polyalkylene oxide structure.

[0110] In addition, when the content of the nonionic surfactant in the electrostatic charge image developing toner is set to Wa and the content of the tin oxide particles is set to Wb, from the viewpoint of color streak suppression, the value of Wa / (Wa+Wb) is preferably greater than 0.010 and less than 0.92, more preferably greater than 0.024 and less than 0.90, further preferably greater than 0.050 and less than 0.80, and particularly preferably greater than 0.10 and less than 0.65.

[0111] -Bonding resin-

[0112] Examples of the binder resin include homopolymers of monomers such as styrenes (e.g., styrene, p-chlorostyrene, α-methylstyrene, etc.), (meth)acrylates (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (e.g., ethylene, propylene, butadiene, etc.), or copolymers of two or more of these monomers.

[0113] Examples of the binder resin include epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, modified rosins and other non-vinyl resins, mixtures of these with the vinyl resins, or graft polymers obtained by polymerizing vinyl monomers in the presence of these.

[0114] These binder resins may be used alone or in combination of two or more.

[0115] Examples of the binder resin include non-crystalline (also referred to as “non-crystalline”) resins and crystalline resins.

[0116] From the viewpoint of color streak suppression, the binder resin preferably includes a crystalline resin, and more preferably includes an amorphous resin and a crystalline resin.

[0117] The content of the crystalline resin is preferably 2% by mass or more and 40% by mass or less, and more preferably 2% by mass or more and 20% by mass or less, relative to the total mass of the binder resin.

[0118] The "crystallinity" of a resin refers to a clear endothermic peak in differential scanning calorimetry (DSC) rather than a step-by-step change in endothermic value. Specifically, it refers to a half-width of the endothermic peak being within 10°C when measured at a heating rate of 10 (°C / min).

[0119] On the other hand, the "amorphous" nature of a resin means that the half width exceeds 10°C, the endothermic value shows a step-wise change, or a clear endothermic peak is not confirmed.

[0120] Examples of the polyester resin include well-known polyester resins.

[0121] In addition, the binder resin may also contain a crystalline polyester resin together with the amorphous polyester resin. The content of the crystalline polyester resin relative to the total mass of the binder resin is preferably 2% by mass or more and 40% by mass or less, and more preferably 2% by mass or more and 20% by mass or less.

[0122] Amorphous polyester resin

[0123] Examples of the non-crystalline polyester resin include polycondensates of polycarboxylic acids and polyols. As the non-crystalline polyester resin, a commercially available product or a synthetic resin may be used.

[0124] Examples of the polycarboxylic acid include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, etc.), anhydrides thereof, or lower (e.g., carbon number 1 or more and 5 or less) alkyl esters thereof. Among these, the polycarboxylic acid is preferably, for example, an aromatic dicarboxylic acid.

[0125] The polycarboxylic acid may be used together with the dicarboxylic acid to obtain a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, or lower (e.g., carbon number 1 to 5) alkyl esters thereof.

[0126] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0127] Examples of the polyol include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), and aromatic diols (e.g., ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, the polyol is preferably an aromatic diol or an alicyclic diol, and more preferably an aromatic diol.

[0128] As the polyol, a trivalent or higher polyol that can obtain a crosslinked structure or a branched structure may be used together with a diol. Examples of the trivalent or higher polyol include glycerin, trimethylolpropane, and pentaerythritol.

[0129] The polyols may be used alone or in combination of two or more.

[0130] The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50°C or higher and 80°C or lower, and more preferably 50°C or higher and 65°C or lower.

[0131] The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, is determined according to the "extrapolated glass transition initiation temperature" described in the method for determining the glass transition temperature of Japanese Industrial Standards (JIS) K 7121-1987 "Method for determining transition temperatures of plastics".

[0132] The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 or more and 1,000,000 or less, and more preferably 7,000 or more and 500,000 or less.

[0133] The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2,000 or more and 100,000 or less.

[0134] The molecular weight distribution Mw / Mn of the amorphous polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less.

[0135] Furthermore, the weight average molecular weight and the number average molecular weight are measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC is performed using a GPC manufactured by Tosoh Corporation: HLC-8120GPC as a measuring device and a column manufactured by Tosoh Corporation: TSKgel SuperHM-M (15 cm), in a THF solvent. The weight average molecular weight and the number average molecular weight are calculated based on the measurement results and using a molecular weight calibration curve made from a monodisperse polystyrene standard sample.

[0136] The amorphous polyester resin can be obtained by a known production method. Specifically, for example, the amorphous polyester resin can be obtained by a method in which the polymerization temperature is set to 180° C. to 230° C., the pressure in the reaction system is reduced as necessary, and the water or alcohol generated during condensation is removed while the reaction is carried out.

[0137] Furthermore, when the monomer of the raw material is insoluble or incompatible at the reaction temperature, a high boiling point solvent may be added as a dissolving aid to dissolve it. In such a case, the polycondensation reaction is carried out while the dissolving aid is distilled off. In the case of the presence of monomers with poor compatibility, the monomers with poor compatibility may be condensed in advance with the acid or alcohol to be polycondensed with the monomers and then polycondensed with the main component.

[0138] Crystalline polyester resin

[0139] Examples of the crystalline polyester resin include polycondensates of polycarboxylic acids and polyols. As the crystalline polyester resin, a commercially available product may be used, and a synthetic resin may also be used.

[0140] Here, in order to easily form a crystalline structure, the crystalline polyester resin is preferably a polycondensate of a polymerizable monomer having a linear aliphatic group rather than a polymerizable monomer having an aromatic group.

[0141] Examples of the polycarboxylic acid include aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalene-2,6-dicarboxylic acid, etc.), anhydrides thereof, or lower (e.g., carbon number of 1 to 5) alkyl esters thereof.

[0142] The polycarboxylic acid may be used together with the dicarboxylic acid to obtain a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure. Examples of the trivalent carboxylic acid include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), anhydrides thereof, or lower (e.g., carbon number 1 or more and 5 or less) alkyl esters thereof.

[0143] As the polycarboxylic acid, a dicarboxylic acid having a sulfonic acid group or a dicarboxylic acid having an ethylenic double bond may be used in combination with these dicarboxylic acids.

[0144] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0145] Examples of the polyol include aliphatic diols (e.g., linear aliphatic diols having a main chain carbon number of 7 or more and 20 or less). Examples of the aliphatic diols include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosane decanediol. Among these, preferred aliphatic diols are 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol.

[0146] A trivalent or higher alcohol may be used together with a diol to obtain a cross-linked structure or a branched structure. Examples of the trivalent or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.

[0147] The polyols may be used alone or in combination of two or more.

[0148] Here, the content of the aliphatic diol in the polyol can be set to 80 mol % or more, preferably 90 mol % or more.

[0149] 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.

[0150] The melting temperature is determined based on a DSC curve obtained by differential scanning calorimetry (DSC) according to the “melting peak temperature” described in the method for determining the melting temperature in JIS K7121-1987 “Methods for determining transition temperatures of plastics”.

[0151] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

[0152] The crystalline polyester resin can be obtained, for example, by a well-known production method, similar to the amorphous polyester resin.

[0153] From the viewpoint of the scratch resistance of the image, the weight average molecular weight (Mw) of the binder resin is preferably 5,000 or more and 1,000,000 or less, more preferably 7,000 or more and 500,000 or less, and particularly preferably 25,000 or more and 60,000 or less. The number average molecular weight (Mn) of the binder resin is preferably 2,000 or more and 100,000 or less. The molecular weight distribution Mw / Mn of the binder resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less.

[0154] The weight average molecular weight and number average molecular weight of the binder resin are measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC is performed using a GPC manufactured by Tosoh Corporation: HLC-8120GPC as a measuring device and a column manufactured by Tosoh Corporation: TSKgel SuperHM-M (15 cm), in a tetrahydrofuran (THF) solvent. The weight average molecular weight and number average molecular weight are calculated based on the measurement results and using a molecular weight calibration curve made from a monodisperse polystyrene standard sample.

[0155] The content of the binder resin is preferably 40% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 90% by mass or less, and still more preferably 60% by mass or more and 85% by mass or less, based on the entire toner base particles.

[0156] The content of the binder resin when the toner mother particles are white toner mother particles is preferably 30 mass % or more and 85 mass % or less, and more preferably 40 mass % or more and 60 mass % or less, relative to the entire white toner mother particles.

[0157] -Release agent-

[0158] Examples of the release agent include hydrocarbon waxes, natural waxes such as carnauba wax, rice wax, and candelilla wax, synthetic waxes such as montan wax, and mineral and / or petroleum waxes, and ester waxes such as fatty acid esters and montanic acid esters. The release agent is not limited thereto.

[0159] The melting temperature of the release agent is preferably 50°C or higher and 110°C or lower, and more preferably 60°C or higher and 100°C or lower.

[0160] The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) according to the “melting peak temperature” described in the method for determining the melting temperature in JIS K7121-1987 “Methods for determining transition temperatures of plastics”.

[0161] The content of the release agent is preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less, based on the entire toner base particles.

[0162] -5'-Chloro-3-hydroxy-2'-methoxy-2-naphthoaniline-

[0163] From the viewpoint of color streak suppression, the toner base particles preferably contain 5'-chloro-3-hydroxy-2'-methoxy-2-naphthylaniline.

[0164] From the viewpoint of color streak suppression, the content of 5'-chloro-3-hydroxy-2'-methoxy-2-naphthylaniline in the electrostatic charge image developing toner in the present embodiment is preferably from 0.1 ppm to 1,000 ppm on a mass basis, more preferably from 1 ppm to 300 ppm, further preferably from 3 ppm to 250 ppm, and particularly preferably from 10 ppm to 200 ppm.

[0165] The content of 5'-chloro-3-hydroxy-2'-methoxy-2-naphthylaniline in the present embodiment refers to a value obtained by quantitative analysis by the following method.

[0166] The content of 5'-chloro-3-hydroxy-2'-methoxy-2-naphthylaniline in the color powder was determined based on a standard curve obtained by measuring 5'-chloro-3-hydroxy-2'-methoxy-2-naphthylaniline in advance by liquid chromatography (LC (liquid chromatography)-UV (Ultraviolet)). Specifically, 0.05 g of the color powder was weighed, and after adding tetrahydrofuran, ultrasonic extraction was performed for 30 minutes. After that, the extract was recovered, and a solution accurately prepared with acetonitrile to 20 mL was used as a sample solution, and the solution was measured by liquid chromatography (LC-UV).

[0167] -Colorants-

[0168] Examples of the colorant include carbon black, chrome yellow, Hansa yellow, benzidine yellow, threne yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watchung red, permanent red, brilliant carmine 3B, brilliant carmine 6B, Dupont Oil Red, pyrazolone red, lithotripter red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, ultramarine blue, calco oil blue, and chromatin. oilblue), methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, malachite green oxalate and other pigments, or acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindigo, dioxazine, thiazine, azomethine, indigo, phthalocyanine, nigrosine, polymethine, triphenylmethane, diphenylmethane, thiazole and other dyes.

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

[0170] The colorant may be a surface-treated colorant as required, or may be used in combination with a dispersant. In addition, a plurality of colorants may be used in combination.

[0171] The content of the colorant is, for example, preferably 1% by mass or more and 30% by mass or less, and more preferably 3% by mass or more and 15% by mass or less, based on the entire toner base particles.

[0172] In addition, from the viewpoint of color streak suppression, the content M of the colorant in the toner base particles is C and the content M of the 5'-chloro-3-hydroxy-2'-methoxy-2-naphthylaniline N The mass ratio (M C / M N ) is preferably 50 or more and 10,000 or less, more preferably 200 or more and 5,000 or less, particularly preferably 500 or more and 2,500 or less.

[0173] -Other additives-

[0174] Examples of other additives include known additives such as magnetic materials, charge control agents, and inorganic powders. These additives are contained in the toner base particles as internal additives.

[0175] -Characteristics of toner masterbatch particles, etc.-

[0176] The toner master particles may be monolayer structured toner master particles or so-called core-shell structured toner master particles (core-shell type particles) including a core (core particle) and a coating layer (shell layer) coating the core. The core-shell structured toner master particles may include, for example, a core containing a binder resin and, if necessary, a colorant and a release agent, etc., and a coating layer containing a binder resin.

[0177] Among them, from the viewpoint of color streak suppression, the toner base particles are preferably core-shell type particles.

[0178] Furthermore, when the toner base particles are core-shell type particles, the nonionic surfactant is preferably contained in both the core and the shell from the viewpoint of color streak suppression.

[0179] The volume average particle size (D 50v ), preferably from 2 μm to 10 μm, more preferably from 4 μm to 8 μm.

[0180] The volume average particle size of the toner was measured using a Coulter Multisizer II (manufactured by Beckman-Coulter) and the electrolyte was measured using an ISOTON-II (manufactured by Beckman-Coulter).

[0181] During measurement, 0.5 mg to 50 mg of a measurement sample is added to 2 mL of a 5% by mass aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate) as a dispersant, and then added to 100 mL to 150 mL of an electrolyte.

[0182] The electrolyte in which the sample was suspended was dispersed by an ultrasonic disperser for 1 minute, and the particle size of each particle in the range of 2 μm to 60 μm was measured by a Coulter Counter II using an aperture of 100 μm. The number of particles sampled was 50,000.

[0183] The measured particle sizes were cumulatively distributed based on volume from the smaller diameter side, and the particle size at which the cumulative distribution reached 50% was defined as the volume average particle size D. 50v .

[0184] In this embodiment, the average circularity of the toner base particles is not particularly limited, but is preferably 0.91 to 0.98, more preferably 0.94 to 0.98, and even more preferably 0.95 to 0.97 from the viewpoint of optimizing the cleanliness of the toner of the image holder.

[0185] In this embodiment, the circularity of the toner master particles is (the circumference of a circle having the same area as the particle projection image) ÷ (the circumference of the particle projection image), and the average circularity of the toner master particles is the circularity that reaches 50% from the smallest side in the distribution of circularity. The average circularity of the toner master particles is obtained by analyzing at least 3,000 toner master particles using a flow-type particle image analyzer.

[0186] For example, when the toner base particles are produced by the agglomeration method, the average circularity of the toner base particles can be controlled by adjusting the stirring speed of the dispersion, the temperature of the dispersion or the holding time in the fusion and / or unification step.

[0187] [Method for producing toner]

[0188] Next, a method for producing toner according to the present embodiment will be described.

[0189] The toner of the present embodiment is obtained by manufacturing toner base particles and then adding external additives to the toner base particles.

[0190] The toner masterbatch particles can also be produced by any method of a dry method (e.g., a kneading and pulverizing method, etc.) or a wet method (e.g., an agglomeration method, a suspension polymerization method, a dissolution suspension method, etc.). These methods are not particularly limited, and known methods can be used. Among these, the toner masterbatch particles can be obtained by an agglomeration method.

[0191] In the kneading and pulverizing method, toner particles can be preferably prepared by kneading a toner forming material including a nonionic surfactant, a binder resin and a release agent, and optionally a colorant and 5'-chloro-3-hydroxy-2'-methoxy-2-naphthylaniline to obtain a kneaded product, and then pulverizing the kneaded product.

[0192] In addition, specifically, for example, when the color powder master particles are manufactured by utilizing the coagulation and unification method, the color powder master particles are manufactured through the following steps: a step of preparing a resin particle dispersion in which resin particles serving as a binding resin are dispersed (resin particle dispersion preparation step); a step of causing the resin particles (and other particles as necessary) to coagulate in the resin particle dispersion (a dispersion obtained by mixing other particle dispersions as necessary) to form coagulated particles (coagulated particle formation step); and a step of heating the coagulated particle dispersion in which the coagulated particles are dispersed to cause the coagulated particles to fuse and / or unify to form the color powder master particles (fusion and / or unification step).

[0193] 5'-Chloro-3-hydroxy-2'-methoxy-2-naphthylaniline may also be added to the dispersion in the step of forming aggregated particles.

[0194] The following describes the details of each step.

[0195] In the following description, a method for obtaining a toner base particle containing a colorant and a release agent is described, but the colorant and the release agent are used as needed. Of course, other additives besides the colorant and the release agent may also be used.

[0196] - Resin particle dispersion preparation step -

[0197] A resin particle dispersion in which resin particles serving as a binder resin are dispersed, a colorant particle dispersion in which colorant particles are dispersed, and a release agent particle dispersion in which release agent particles are dispersed are prepared.

[0198] The resin particle dispersion is prepared by dispersing the resin particles in a dispersion medium using a surfactant, for example.

[0199] Examples of the dispersion medium used in the resin particle dispersion include aqueous media.

[0200] Examples of the aqueous medium include water such as distilled water and ion-exchanged water, and alcohols, etc. These may be used alone or in combination of two or more.

[0201] Examples of surfactants include anionic surfactants such as sulfate ester salts, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyols. Among these, anionic surfactants and cationic surfactants are particularly useful. Nonionic surfactants may be used in combination with anionic surfactants or cationic surfactants.

[0202] Among them, it is preferred to use a nonionic surfactant, and it is more preferred to use a nonionic surfactant in combination with an anionic surfactant or a cationic surfactant.

[0203] The surfactant may be used alone or in combination of two or more.

[0204] In the resin particle dispersion, as a method for dispersing the resin particles in the dispersion medium, for example, general dispersion methods such as a rotary shearing homogenizer, or a ball mill, a sand mill, and a dyno mill with a medium can be cited. In addition, depending on the type of resin particles, the resin particles can also be dispersed in the dispersion medium by using a phase inversion emulsification method. The so-called phase inversion emulsification method is the following method: the resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, an alkali is added to the organic continuous phase (O phase) and neutralized, and then an aqueous medium (W phase) is added, thereby performing a phase inversion from W / O to O / W, thereby dispersing the resin in the aqueous medium in the form of particles.

[0205] The volume average particle size of the resin particles dispersed in the resin particle dispersion is, for example, preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and still more preferably 0.1 μm or more and 0.6 μm or less.

[0206] The volume average particle size of the resin particles is a particle size distribution obtained by measurement using a laser diffraction particle size distribution measuring device (e.g., LA-700 manufactured by Horiba, Ltd.), and a cumulative distribution is drawn from the small particle size side for the volume relative to the divided particle size range (channel), and the particle size that accumulates to 50% relative to the total particles is measured as the volume average particle size D50v. The volume average particle size of particles in other dispersions is also measured in the same manner.

[0207] The content of the resin particles contained in the resin particle dispersion is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.

[0208] Similar to the resin particle dispersion, for example, a colorant particle dispersion and a release agent particle dispersion are also prepared. That is, the volume average particle size of the particles in the resin particle dispersion, the dispersion medium, the dispersion method, and the content of the particles are the same for the colorant particles dispersed in the colorant particle dispersion and the release agent particles dispersed in the release agent particle dispersion.

[0209] - Agglomerated Particle Formation Steps -

[0210] Next, the resin particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mixed. At this time, a nonionic surfactant may be mixed, and 5'-chloro-3-hydroxy-2'-methoxy-2-naphthylaniline may also be mixed.

[0211] Then, the resin particles, the colorant particles, and the release agent particles are heterogeneously aggregated in the mixed dispersion to form aggregated particles having a diameter close to the target diameter of the toner mother particles and including the resin particles, the colorant particles, and the release agent particles.

[0212] Specifically, for example, a coagulant is added to the mixed dispersion, and the pH value of the mixed dispersion is adjusted to be acidic (for example, a pH value of not less than 2 and not more than 5), and after adding a dispersion stabilizer as needed, it is heated to a temperature close to the glass transition temperature of the resin particles (specifically, for example, the glass transition temperature of the resin particles is not less than -30°C and not more than -10°C), so that the particles dispersed in the mixed dispersion are agglomerated to form agglomerated particles.

[0213] In the step of forming aggregated particles, for example, a coagulant may be added to the mixed dispersion using a rotary shearing homogenizer under stirring at room temperature (e.g., 25° C.), the pH of the mixed dispersion may be adjusted to an acidic state (e.g., a pH of 2 or more and 5 or less), a dispersion stabilizer may be added as needed, and then the mixture may be heated.

[0214] Examples of the coagulant include a surfactant having a polarity opposite to that of the surfactant contained in the mixed dispersion, an inorganic metal salt, and a divalent or higher metal complex. When a metal complex is used as the coagulant, the amount of the surfactant used can be reduced, and the charging characteristics are improved.

[0215] If necessary, an additive that forms a complex with the metal ion of the coagulant or a similar bond may be used together with the coagulant. As the additive, a chelating agent can be preferably used.

[0216] Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; and inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide.

[0217] As the chelating agent, a water-soluble chelating agent may also be used. Examples of the chelating agent include hydroxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid; and aminocarboxylic acids such as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA).

[0218] The amount of the coagulant added is preferably 0.01 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass, relative to 100 parts by mass of the resin particles.

[0219] - Fusion and / or unification steps-

[0220] Secondly, the agglomerated particle dispersion containing the agglomerated particles is heated to a temperature, for example, above the glass transition temperature of the resin particles (for example, a temperature 30°C to 50°C higher than the glass transition temperature of the resin particles) and above the melting temperature of the release agent, so that the agglomerated particles are fused and / or unified to form color powder masterbatch particles.

[0221] In the fusion and / or unification step, the resin and the release agent are in a fused state at a temperature above the glass transition temperature of the resin particles and above the melting temperature of the release agent. Thereafter, the mixture is cooled to obtain the toner mother particles.

[0222] As a method for adjusting the aspect ratio of the release agent in the color powder, the aspect ratio can be adjusted by maintaining the temperature around the solidification point of the release agent for a certain period of time during cooling to allow crystal growth. By using two or more release agents with different melting points to promote crystal growth during cooling, the aspect ratio can be adjusted.

[0223] The toner masterbatch particles are obtained through the above steps.

[0224] The color powder master particles can also be manufactured through the following steps: after obtaining a condensed particle dispersion in which condensed particles are dispersed, the condensed particle dispersion is further mixed with a resin particle dispersion in which resin particles are dispersed, so as to condense the resin particles by attaching them to the surface of the condensed particles to form a second condensed particle; and the second condensed particle dispersion in which the second condensed particles are dispersed is heated to cause the second condensed particles to fuse and / or merge into one to form a color powder master particle with a core-shell structure.

[0225] After the fusion and / or unification step is completed, the toner master particles formed in the solution are subjected to a known washing step, a solid-liquid separation step, and a drying step to obtain the toner master particles in a dry state. From the perspective of chargeability, the washing step can be fully carried out by replacement washing using ion exchange water. From the perspective of productivity, the solid-liquid separation step can be carried out by suction filtration, pressure filtration, etc. From the perspective of productivity, the drying step can be carried out by freeze drying, air flow drying, fluidized drying, vibration-type fluidized drying, etc.

[0226] The toner of the present embodiment can be produced, for example, by adding an external additive to the obtained dry toner master particles and mixing them. The mixing can be performed, for example, using a V-type blender, a Henschel mixer, a Loedige mixer, etc. Furthermore, if necessary, a vibration sieving machine, a wind sieving machine, etc. can be used to remove coarse particles of the toner.

[0227] <Electrostatic image developer>

[0228] The electrostatic charge image developer of this embodiment includes at least the toner of this embodiment. The electrostatic charge image developer of this embodiment may be a single-component developer including only the toner of this embodiment, or a two-component developer including the toner and a carrier.

[0229] The carrier is not particularly limited, and known carriers can be cited. Examples of the carrier include: a coated carrier in which a core material containing magnetic powder is coated with a resin; a magnetic powder dispersion carrier in which magnetic powder is dispersed in a matrix resin and formulated; a resin impregnated carrier in which a porous magnetic powder is impregnated with a resin, etc. The magnetic powder dispersion carrier and the resin impregnated carrier can also be a carrier in which the constituent particles of the carrier are set as a core material and the surface thereof is coated with a resin.

[0230] Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt; and magnetic oxides such as ferrite and magnetite.

[0231] Examples of the coating resin and matrix resin include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylate copolymer, pure silicone resin or modified products thereof containing organic siloxane bonds, fluororesins, polyesters, polycarbonates, phenol resins, epoxy resins, etc. The coating resin and matrix resin may also contain additives such as conductive particles. Examples of the conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0232] When the surface of the core material is coated with a resin, a coating layer forming solution prepared by dissolving a coating resin and various additives (used as needed) in an appropriate solvent can be used for coating. The solvent is not particularly limited, and can be selected by considering the type of resin used or coating adaptability. Specific resin coating methods include: an immersion method in which the core material is immersed in a coating layer forming solution; a spray method in which the coating layer forming solution is sprayed on the surface of the core material; a fluidized bed method in which the coating layer forming solution is sprayed while the core material is suspended by flowing air; a kneading coater method in which the core material of the carrier is mixed with the coating layer forming solution in a kneading coater and then the solvent is removed.

[0233] 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.

[0234] <Image forming apparatus, image forming method>

[0235] The image forming apparatus and image forming method according to the present embodiment will be described.

[0236] The image forming device of the present embodiment includes: an image holder; a charging member for charging the surface of the image holder; an electrostatic charge image forming member for forming an electrostatic charge image on the surface of the charged image holder; a developing member for storing an electrostatic charge image developer and developing the electrostatic charge image formed on the surface of the image holder into a toner image using the electrostatic charge image developer; a transfer member for transferring the toner image formed on the surface of the image holder to the surface of a recording medium; and a fixing member for fixing the toner image transferred to the surface of the recording medium. Furthermore, as the electrostatic charge image developer, the electrostatic charge image developer of the present embodiment can be applied.

[0237] In the image forming device of the present embodiment, an image forming method (the image forming method of the present embodiment) is implemented, and the image forming method includes: a charging step of charging the surface of an image retaining body; an electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image retaining body; a developing step of developing the electrostatic charge image formed on the surface of the image retaining body into a toner image using the electrostatic charge image developer of the present embodiment; a transfer step of transferring the toner image formed on the surface of the image retaining body to the surface of a recording medium; and a fixing step of fixing the toner image transferred to the surface of the recording medium.

[0238] The image forming device of this embodiment can apply the following well-known image forming devices: a device using a direct transfer method for directly transferring a toner image formed on the surface of an image retaining body to a recording medium; a device using an intermediate transfer method for transferring a toner image formed on the surface of an image retaining body to the surface of an intermediate transfer body for the first time, and for a second time transferring the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium; a device including a cleaning component for cleaning the surface of the image retaining body before charging after the transfer of the toner image; a device including a static eliminating component for eliminating static by irradiating the surface of the image retaining body with static eliminating light after the transfer of the toner image and before charging, etc.

[0239] In the case where the image forming device of the present embodiment is an intermediate transfer type device, the transfer component can, for example, be applied with the following structure, which comprises an intermediate transfer body for transferring the toner image to the surface, a primary transfer component for transferring the toner image formed on the surface of the image retaining body to the surface of the intermediate transfer body for the first time, and a secondary transfer component for secondarily transferring the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium.

[0240] In the image forming apparatus of this embodiment, for example, the part including the developing component may also be a box structure (processing box) detachably mounted on the image forming apparatus. As the processing box, for example, a processing box including a developing component that accommodates the electrostatic charge image developer of this embodiment can be preferably used.

[0241] Hereinafter, an example of the image forming apparatus of the present embodiment will be described, but the present invention is not limited thereto. Figure 1 The main parts shown in FIG. 1 are described, and the description of other parts is omitted.

[0242] Figure 1 It is a diagram schematically showing the configuration of the image forming apparatus according to the present embodiment.

[0243] Figure 1The image forming apparatus shown includes first to fourth image forming units 10Y, 10M, 10C, 10K (image forming means) of an electronic photographic method for outputting images of yellow (Y), magenta (M), cyan (C), and black (K) colors based on color-decomposed image data. These image forming units (hereinafter, also referred to as "units") 10Y, 10M, 10C, 10K are arranged side by side at a predetermined distance from each other in the horizontal direction. These units 10Y, 10M, 10C, 10K may also be process cartridges detachably mounted on the image forming apparatus.

[0244] An intermediate transfer belt (an example of an intermediate transfer body) 20 is extended above each unit 10Y, 10M, 10C, and 10K through each unit. The intermediate transfer belt 20 is wound around a driving roller 22 and a supporting roller 24 that are in contact with the inner surface of the intermediate transfer belt 20, and moves in the direction from the first unit 10Y to the fourth unit 10K. A force is applied to the supporting roller 24 in a direction away from the driving roller 22 by a spring (not shown), so that tension is applied to the intermediate transfer belt 20 wound around the two. An intermediate transfer belt cleaning device 30 is provided on the image holding surface side of the intermediate transfer belt 20 facing the driving roller 22.

[0245] The developing devices (an example of developing means) 4Y, 4M, 4C, 4K of the respective units 10Y, 10M, 10C, 10K are supplied with yellow, magenta, cyan, and black toners contained in toner boxes 8Y, 8M, 8C, 8K, respectively.

[0246] The first to fourth units 10Y, 10M, 10C, and 10K have the same configuration and operation, and therefore the first unit 10Y disposed on the upstream side in the intermediate transfer belt moving direction and forming a yellow image will be representatively described here.

[0247] The first unit 10Y has a photosensitive body 1Y that functions as an image holder. The following are arranged in order around the photosensitive body 1Y: a charging roller (an example of a charging member) 2Y that charges the surface of the photosensitive body 1Y to a predetermined potential; an exposure device (an example of an electrostatic charge image forming member) 3 that forms an electrostatic charge image by exposing the charged surface to a laser beam 3Y based on a color-decomposed image signal; a developing device (an example of a developing member) 4Y that supplies charged toner to the electrostatic charge image and develops the electrostatic charge image; a primary transfer roller (an example of a primary transfer member) 5Y that transfers the developed toner image to the intermediate transfer belt 20; and a photosensitive body cleaning device (an example of an image holder cleaning member) 6Y that removes the toner remaining on the surface of the photosensitive body 1Y after the primary transfer.

[0248] The primary transfer roller 5Y is arranged inside the intermediate transfer belt 20 and is provided at a position facing the photoreceptor 1Y. A bias power supply (not shown) for applying a primary transfer bias is connected to each of the primary transfer rollers 5Y, 5M, 5C, and 5K of each unit. Each bias power supply changes the value of the transfer bias applied to each primary transfer roller by control of a control unit (not shown).

[0249] Next, the operation of forming a yellow image in the first unit 10Y will be described.

[0250] First, before the operation, the surface of the photoreceptor 1Y is charged to a potential of -600 V to -800 V by the charging roller 2Y.

[0251] The photoreceptor 1Y is conductive (for example, the volume resistivity at 20° C. is 1×10 -6 The photosensitive layer is formed by laminating a photosensitive layer on a substrate with a resistance of 100 Ωcm or less. The photosensitive layer is usually high in resistance (resistance of a general resin), and has a property that the resistivity of the portion irradiated with the laser light changes when irradiated with laser light. Therefore, according to the image data for yellow sent from the control unit (not shown), the surface of the charged photoreceptor 1Y is irradiated with laser light 3Y from the exposure device 3. As a result, an electrostatic charge image of a yellow image pattern is formed on the surface of the photoreceptor 1Y.

[0252] The so-called electrostatic charge image is an image formed on the surface of the photoreceptor 1Y by charging, and is a so-called negative latent image formed by utilizing the laser light 3Y to reduce the resistivity of the irradiated portion of the photosensitive layer, causing the charged charge on the surface of the photoreceptor 1Y to flow, while the charge on the portion not irradiated by the laser light 3Y remains.

[0253] The electrostatic charge image formed on the photoreceptor 1Y rotates to a predetermined development position as the photoreceptor 1Y moves. Then, at the development position, the electrostatic charge image on the photoreceptor 1Y is developed into a toner image by the developing device 4Y and becomes visible.

[0254] The developing device 4Y contains, for example, an electrostatic charge image developer containing at least yellow toner and a carrier. The yellow toner is stirred and frictionally charged inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charge on the photoreceptor 1Y, and is retained on a developer roller (an example of a developer retainer). Then, the surface of the photoreceptor 1Y is difficult to pass through the developing device 4Y, so that the yellow toner is electrostatically attached to the de-charged latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed using the yellow toner. The photoreceptor 1Y formed with the yellow toner image then moves at a predetermined speed, and the toner image developed on the photoreceptor 1Y is transported to a predetermined primary transfer position.

[0255] When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer position, a primary transfer bias is applied to the primary transfer roller 5Y, and the electrostatic force from the photoreceptor 1Y to the primary transfer roller 5Y acts on the toner image, thereby transferring the toner image on the photoreceptor 1Y to the intermediate transfer belt 20. The transfer bias applied at this time is 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. The toner remaining on the photoreceptor 1Y is removed and recovered by the photoreceptor cleaning device 6Y.

[0256] The primary transfer bias applied to the primary transfer rollers 5M, 5C, and 5K after the second unit 10M is also controlled by the first unit.

[0257] In this way, the intermediate transfer belt 20 to which the yellow toner image has been transferred in the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and toner images of respective colors are superimposed to perform multi-transfer.

[0258] The intermediate transfer belt 20 to which the toner images of four colors are multi-transferred through the first to fourth units arrives at a secondary transfer section including 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 member) 26 disposed on the image holding surface side of the intermediate transfer belt 20. On the other hand, a recording paper (an example of a recording medium) P is supplied to a gap between the secondary transfer roller 26 and the intermediate transfer belt 20 at a predetermined time point via a supply mechanism, and a secondary transfer bias is applied to the support roller 24. The transfer bias applied at this time has the same polarity (-) as the polarity (-) of the toner, and the electrostatic force from the intermediate transfer belt 20 to the recording paper P acts on the toner image, thereby transferring the toner image on the intermediate transfer belt 20 to the recording paper P. The secondary transfer bias at this time is determined based on the resistance detected by the resistance detection member (not shown) that detects the resistance of the secondary transfer section, and is voltage-controlled.

[0259] The recording paper P to which the toner image is transferred is fed into the pressure contact portion (nip portion) of a pair of fixing rollers in the fixing device (an example of a fixing member) 28, and the toner image is fixed on the recording paper P, thereby forming a fixed image. The recording paper P to which the color image has been fixed is discharged toward the discharge portion, and a series of color image forming operations are completed.

[0260] As the recording paper P to transfer 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 sheets can also be cited. In order to further improve the smoothness of the image surface after fixing, it is preferred that the surface of the recording paper P is also smooth, for example, coated paper obtained by coating the surface of ordinary paper with a resin or the like, coated paper for printing, etc. can be preferably used.

[0261] <Process cartridge, toner cartridge>

[0262] The processing box of this embodiment is a processing box that can be detachably installed in an image forming device: it includes a developing component that accommodates the electrostatic charge image developer of this embodiment and uses the electrostatic charge image developer to develop the electrostatic charge image formed on the surface of the image retaining body into a toner image.

[0263] The process cartridge of this embodiment may be configured to include a developing member and, if necessary, at least one member selected from other members such as an image holding member, a charging member, an electrostatic charge image forming member, and a transfer member.

[0264] An example of a process cartridge according to the present embodiment is shown below, but the present invention is not limited thereto. Figure 2 The main parts shown in FIG. 1 are described, and the description of other parts is omitted.

[0265] Figure 2 It is a schematic structural diagram showing an example of the process cartridge according to the present embodiment.

[0266] Figure 2 The processing box 200 shown, for example, utilizes a frame 117 including a mounting guide 116 and an opening 118 for exposure, and combines and holds a photosensitive body 107 (an example of an image retaining body), a charging roller 108 (an example of a charging component) disposed around the photosensitive body 107, a developing device 111 (an example of a developing component), and a photosensitive body cleaning device 113 (an example of a cleaning component) in an integral manner, thereby being boxed.

[0267] Figure 2 109 denotes an exposure device (an example of an electrostatic charge image forming member), 112 denotes a transfer device (an example of a transfer member), 115 denotes a fixing device (an example of a fixing member), and 300 denotes recording paper (an example of a recording medium).

[0268] Next, the toner cartridge according to the present embodiment will be described.

[0269] The toner cartridge of the present embodiment is a toner cartridge that stores the toner of the present embodiment and is detachably mounted in an image forming apparatus. The toner cartridge stores replenishment toner to be supplied to a developing unit provided in the image forming apparatus.

[0270] Figure 1 The image forming apparatus shown is an image forming apparatus having a configuration in which toner cartridges 8Y, 8M, 8C, and 8K are detachably mounted, and the developing devices 4Y, 4M, 4C, and 4K are connected to toner cartridges corresponding to the respective colors by toner supply pipes (not shown). When the toner stored in the toner cartridge becomes low, the toner cartridge is replaced.

[0271] [Example]

[0272] Hereinafter, examples of the present invention will be described, but the present invention is not limited to the following examples. In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0273] The number average particle size and free amount of the external additive and the content of 5'-chloro-3-hydroxy-2'-methoxy-2-naphthylaniline were measured by the method described above.

[0274] <Preparation of polyester resin particle dispersion>

[0275] [Preparation of polyester resin particle dispersion]

[0276] ·Bisphenol A ethylene oxide 2.2 molar adduct: 40 molar parts

[0277] Bisphenol A propylene oxide 2.2 molar adduct: 60 molar parts

[0278] Dimethyl terephthalate: 60 parts by mole

[0279] Dimethyl fumarate: 15 mol parts

[0280] Dodecenylsuccinic anhydride: 20 mol parts

[0281] Trimellitic anhydride: 5 mol parts

[0282] In a reaction vessel equipped with a stirrer, a thermometer, a condenser and a nitrogen inlet tube, 0.25 parts of tin dioctylate are added to a total of 100 parts of the monomers, except for fumaric acid and trimellitic anhydride in the monomers. After reacting at 235°C for 6 hours under a nitrogen flow, the temperature is lowered to 200°C, and fumaric acid and trimellitic anhydride are added and reacted for 1 hour. It takes 5 hours to raise the temperature to 220°C, and polymerization is carried out under a pressure of 10 kPa until the desired molecular weight is reached, thereby obtaining a light yellow transparent polyester resin. The weight average molecular weight of the polyester resin is 35,000, the number average molecular weight is 8,000, and the glass transition temperature is 59°C.

[0283] Next, the polyester resin was dispersed using a Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) modified into a high-temperature and high-pressure disperser. The composition ratio was 80% ion exchange water and 20% polyester resin. The pH value was adjusted to 8.5 with ammonia. The rotor was rotated at 60 Hz and the pressure was 5 kg / cm 2 , Carbitron was operated under the condition of heating at 140° C. using a heat exchanger to obtain a polyester resin dispersion (solid content: 20%).

[0284] The volume average particle size of the resin particles in the dispersion was 130 nm. Deionized water was added to the dispersion to adjust the solid content to 20%, thereby preparing a polyester resin particle dispersion.

[0285] <Preparation of Colorant Particle Dispersion>

[0286] Magenta pigment (CI Pigment Red 238, manufactured by Sanyo Pigment Co., Ltd.): 70 parts

[0287] Anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1 part

[0288] Ion exchange water: 200 parts

[0289] The materials were mixed and dispersed for 10 minutes using a homogenizer (Ultraturrax T50 manufactured by IKA Co., Ltd.) Deionized water was added so that the solid content in the dispersion became 20% by mass, thereby obtaining a colorant particle dispersion in which colorant particles having a volume average particle size of 190 nm were dispersed.

[0290] <Preparation of release agent particle dispersion>

[0291] Polyethylene wax (hydrocarbon wax: trade name "Polywax 725 (manufactured by Baker Petrolite Co., Ltd.)", melting point 104°C): 270 parts

[0292] Anionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., active ingredient amount: 60%): 13.5 parts (3.0% as active ingredient relative to the release agent)

[0293] Ion exchange water: 21.6 parts

[0294] The components were mixed, and the release agent was dissolved in a pressure ejection homogenizer (manufactured by Gaulin, Gaulin homogenizer) at an internal liquid temperature of 120°C, and then dispersed at a dispersion pressure of 5 MPa for 120 minutes, and then dispersed at 40 MPa for 360 minutes, and cooled to obtain a release agent particle dispersion. The volume average particle size D50 of the particles in the release agent particle dispersion was 225 nm. Thereafter, ion exchange water was added to adjust the solid content concentration to 20.0%.

[0295] <Preparation of Toner Master Particles 1>

[0296] Polyester resin particle dispersion: 100 parts by mass

[0297] Colorant particle dispersion: 10 parts by mass

[0298] Release agent particle dispersion: 9 parts by mass

[0299] 5'-Chloro-3-hydroxy-2'-methoxy-2-naphthylaniline (manufactured by Tokyo Chemical Industry Co., Ltd., diluted to a 1% aqueous solution and used): 0.2 parts by mass

[0300] Nonionic surfactant (Emulgen 150, manufactured by Kao Corporation): 0.07 parts by mass

[0301] Anionic surfactant (Tayca Power, manufactured by Tayca Co., Ltd.): 0.1 parts by mass

[0302] 0.3M (mol / L) nitric acid aqueous solution: 0.4 parts by mass

[0303] Ion exchange water: 200 parts by mass

[0304] The components were placed in a round stainless steel flask, dispersed using a homogenizer (Ultraturrax T50 manufactured by IKA), heated to 42°C in a heating oil bath and maintained for 30 minutes, and then 50 parts by weight of additional polyester resin particle dispersion was added at a stage where agglomerated particles were confirmed to be formed, and then maintained for another 30 minutes. Then, nitrosotriacetic acid sodium salt (Chelest 70 manufactured by Chelest Co., Ltd.) was added in an amount of 3% by weight of the total solution. After that, 1N (=mol / L) sodium hydroxide aqueous solution was added steadily until the pH value reached 7.2, and then stirring was continued and heating was continued to 85°C, and maintained for 3.0 hours. After that, the reaction product was filtered and washed with ion exchange water, and then dried using a vacuum dryer to obtain a toner master particle 1 (master particle 1).

[0305] <Production of Toner Master Particles 2>

[0306] In the preparation of color powder master particles 1, the addition amount of nonionic surfactant was changed to 0.91 mass parts, and the addition amount of 5'-chloro-3-hydroxy-2'-methoxy-2-naphthylaniline was changed to 1.0 mass parts. In addition, color powder master particles 2 (master particles 2) were prepared using the same method as the preparation of color powder master particles 1.

[0307] <Production of Toner Master Particles 3 and 4>

[0308] In the preparation of color powder master particle 1, the nonionic surfactant was changed to emulgen A-60 (manufactured by Kao Co., Ltd.) and emulgen 420 (manufactured by Kao Co., Ltd.), and other than that, the same method as the preparation of color powder master particle 1 was used to prepare color powder master particles 3 to 4 (master particles 3 to master particles 4).

[0309] <Production of Toner Master Particles 5>

[0310] In the preparation of the toner master particles 1, toner master particles 5 (master particles 5) were prepared by the same method as that of the toner master particles 1, except that the nonionic surfactant was changed to S241 (manufactured by AGC SEIMI Chemical Co., Ltd.) which is a fluorine-based surfactant.

[0311] <Production of Toner Master Particles 6>

[0312] -Manufacturing of kneading and pulverizing toner particles-

[0313] Polyester resin (linear polyester formed by polycondensation of terephthalic acid / bisphenol A ethylene oxide adduct / cyclohexanedimethanol, Mn=4,000, Mw=12,000, Tg=62°C): 100 parts by mass

[0314] Magenta pigment (CI Pigment Red 238, manufactured by Sanyo Pigment Co., Ltd.): 4 parts by mass

[0315] 5'-Chloro-3-hydroxy-2'-methoxy-2-naphthylaniline (manufactured by Tokyo Chemical Industry Co., Ltd., diluted to a 1% aqueous solution and used): 0.2 parts by mass

[0316] · Emulgen 150 (manufactured by Kao Corporation): 0.07 parts by mass

[0317] The above components are fully pre-mixed with a Henschel mixer, melt-kneaded with a biaxial roll mill, and then finely pulverized with a jet mill after cooling. The mixture is then classified twice with a pneumatic classifier to produce toner mother particles 6 (mother particles 6).

[0318] <Production of Toner Master Particles 7>

[0319] -Manufacturing of Styrene Toner-

[0320] <<Preparation of styrene-acrylic resin particle dispersion>>

[0321] 370 parts of styrene, 30 parts of n-butyl acrylate, 8 parts of acrylic acid, 24 parts of dodecanethiol, and 4 parts of carbon tetrabromide were mixed and dissolved in a flask in which 6 parts of a nonionic surfactant (Nonypol 400, manufactured by Sanyo Chemical Industries, Ltd.) and 10 parts of anionic surfactant (Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were dissolved in 550 parts of ion exchange water for emulsion polymerization, and the mixture was slowly mixed for 10 minutes and 50 parts of ion exchange water in which 4 parts of ammonium persulfate were dissolved were added. After nitrogen substitution, the flask was stirred and heated with an oil bath until the contents reached 70°C, and the emulsion polymerization was continued for 5 hours in the above state. As a result, a styrene-acrylic resin particle dispersion in which resin particles of 150 nm, Tg=58°C, and weight average molecular weight Mw=11,500 were dispersed was obtained. The solid content concentration of the dispersion was 40% by mass.

[0322] <<Preparation of Color Masterbatch>>

[0323] Styrene-acrylic resin particle dispersion: 100 parts

[0324] Colorant dispersion: 10 parts

[0325] Release agent dispersion: 9 parts

[0326] Polyaluminum hydroxide (manufactured by Asada Chemical Industry Co., Ltd., Paho 2S): 0.5 parts

[0327] 5'-Chloro-3-hydroxy-2'-methoxy-2-naphthylaniline: 0.2 parts

[0328] Nonionic surfactant (Emulgen 150, manufactured by Kao Corporation): 0.07 parts

[0329] Ion exchange water: 200 parts

[0330] In a round stainless steel flask, the above ingredients were mixed and dispersed using a homogenizer (Ultraturrax T50: manufactured by IKA), and then stirred in the flask in a heating oil bath and heated to 40°C. After being kept at 40°C for 30 minutes, it was confirmed that agglomerated particles with a D50 of 4.5 μm were generated. The temperature of the heating oil bath was then increased and kept at 56°C for 1 hour, and the D50 became 5.3 μm. Thereafter, 26 parts by mass of a styrene-acrylic resin particle dispersion was added to the dispersion containing the agglomerated particles, and the temperature of the heating oil bath was increased to 50°C and kept for 30 minutes. 1N (=mol / L) of sodium hydroxide was added to the dispersion containing the agglomerated particles, and the pH value of the system was adjusted to 7.0. The stainless steel flask was sealed and magnetically sealed, and stirring and heating to 80°C were continued for 4 hours. After cooling, the toner mother particles were separated by filtration, washed four times with ion exchange water, and then freeze-dried to obtain toner mother particles 7 (mother particles 7).

[0331] <Production of Toner Master Particles 8>

[0332] In the preparation of the toner base particles 1 , toner base particles 8 (base particles 8 ) were prepared by the same method as that of the preparation of the toner base particles 1 , except that the amount of the nonionic surfactant added was changed to 0.04 parts by mass.

[0333] <Production of Toner Master Particles 9>

[0334] In the preparation of the toner base particles 1 , toner base particles 9 (base particles 9 ) were prepared by the same method as that of the preparation of the toner base particles 1 , except that the amount of the nonionic surfactant added was changed to 1.2 parts by mass.

[0335] (Example 1 to Example 20, and Comparative Example 1 to Comparative Example 5)

[0336] The toner mother particles described in Table 1 were mixed with tin oxide particles having a number average particle size described in Table 1 in an amount (content relative to the total mass of the toner) described in Table 1 using a sample mill at 10,000 rpm for 30 seconds. Thereafter, the toner mother particles were sieved using a vibrating sieve with a mesh size of 45 μm to prepare a toner (toner for electrostatic image development). The volume average particle size of each toner obtained was 6.5 μm.

[0337] (Comparative Example 6)

[0338] Toner of Comparative Example 6 was prepared by the same method as that of Example 1 except that 1.0 part by mass of silica TG-6020 (manufactured by Cabot Corporation) having a number average particle size of 200 nm was added instead of tin oxide using Toner Base Particles 1.

[0339] <Production of electrostatic image developer>

[0340] 8 parts by mass of the obtained electrostatic image developing toner and 92 parts by mass of a resin-coated ferrite carrier (average particle size: 35 μm) were mixed with a V-type blender to prepare respective developers (electrostatic image developers).

[0341] <Color streak suppression evaluation>

[0342] Even when low-image-density printing was continuously performed after being left in a high-temperature, high-humidity environment, the color-streaking suppressive property at one end portion in the width direction of the image holder was evaluated as follows.

[0343] "700 Digital Color Press" manufactured by Fuji Xerox (Co., Ltd.) was prepared, and the developer thereof was filled with the obtained developer.

[0344] After being left to stand at high temperature and high humidity (28° C. and 85% RH) for 1 day, images having an image density of 1% were continuously output onto 100,000 sheets of A4 paper.

[0345] The occurrence of color fringes in the image portion formed at one end portion in the width direction of the image holding member on the opposite side to the port for supplying toner to the magnetic roller was visually observed and evaluated based on the following criteria.

[0346] G1: Paper with printed images that do not produce color streaks

[0347] G2: The number of printed image sheets with color streaks is 1 or more and 5 or less

[0348] G3: The number of printed images with color stripes is more than 5 and less than 10.

[0349] G4: The number of printed images with color stripes is more than 10 and less than 15.

[0350] G5: Printed image with color stripes exceeding 15 sheets

[0351] The evaluation results are summarized in Table 1.

[0352] [Table 1]

[0353]

[0354] As can be seen from the results shown in Table 1, the electrostatic charge image developing toner of this embodiment is superior to the electrostatic charge image developing toner of the comparative example in suppressing color streaks at one end portion in the width direction of the image retaining body, even when low image density printing is continuously performed after being placed in a high temperature and high humidity environment.

Claims

1. A toner for developing electrostatic charge images, comprising: The toner masterbatch particles at least include a nonionic surfactant, a binder resin and a release agent; as well as External additives, The content of the nonionic surfactant is 0.05 mass % or more and 1 mass % or less relative to the total mass of the toner, The external additive comprises tin oxide particles, The number average particle size of the tin oxide particles is 0.01 μm or more and 10 μm or less, The content of the tin oxide particles is 0.01 mass % or more and 10 mass % or less relative to the total mass of the toner. 2 . The electrostatic image developing toner according to claim 1 , wherein a content of the tin oxide particles is 0.1% by mass or more and 2.0% by mass or less relative to the total mass of the toner.

3. The electrostatic image developing toner according to claim 1, wherein when the content of the nonionic surfactant in the toner is Wa and the content of the tin oxide particles is Wb, the value of Wa / (Wa+Wb) is greater than or equal to 0.024 and less than or equal to 0.

90. 4 . The electrostatic charge image developing toner according to claim 1 , wherein the toner base particles further contain a colorant. 5 . The electrostatic charge image developing toner according to claim 1 , wherein the toner mother particles further contain 5′-chloro-3-hydroxy-2′-methoxy-2-naphthylaniline. 6 . The electrostatic image developing toner according to claim 5 , wherein the content of the 5′-chloro-3-hydroxy-2′-methoxy-2-naphthylaniline is 1 ppm or more and 300 ppm or less based on the total mass of the toner.

7. The electrostatic charge image developing toner according to claim 1, wherein the nonionic surfactant is a compound having a polyalkyleneoxy structure.

8. The electrostatic charge image developing toner according to claim 7, wherein the nonionic surfactant is a compound having a polyethyleneoxy structure. 9 . The electrostatic charge image developing toner according to claim 1 , wherein the binder resin comprises a crystalline resin. 10 . The electrostatic image developing toner according to claim 1 , wherein the toner mother particles are core-shell type particles.

11. An electrostatic charge image developer comprising the electrostatic charge image developing toner according to claim 1.

12. A toner cartridge, containing the electrostatic charge image developing toner according to claim 1, and detachably mounted in an image forming device.

Images