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

Abstract

An electrostatic charge image developing toner, an electrostatic charge image developer, a toner cartridge, a process cartridge, and an image forming apparatus and method, the electrostatic charge image developing toner including toner particles containing a resin and a colorant, when the Net intensity of the Br element measured by fluorescent X-ray analysis in the toner particles is Ibr and the Net intensity of the S element measured by fluorescent X-ray analysis is IS, Ibr is 1 kcps or more and 30 kcps or less, and IS / Ibr is 0.005 or more and 1.2 or less.

Description

Technical Field

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

[0002] Patent document 1 discloses a method for manufacturing a toner for electrophotography, wherein the toner for electrophotography is composed of toner particles, the toner particles containing a colorant and a binder resin, the colorant being obtained by a chelate reaction between a pigment compound having a specific structure and a copper complex compound having a specific structure. The method for manufacturing the toner for electrophotography includes the following steps: adding a coagulant composed of a compound not containing metal atoms to an aqueous medium in which microparticles based on the binder resin, microparticles based on the above-mentioned pigment compound, and microparticles based on the above-mentioned copper complex compound are dispersed, so as to cause the microparticles based on the binder resin, the microparticles based on the pigment compound, and the microparticles based on the copper complex compound to coagulate.

[0003] Patent Document 2 discloses a magenta toner for electrostatic image development, characterized in that the magenta toner contains an amorphous resin and a crystalline polyester resin as binder resins, and comprises a quinacridone pigment having a specific structure, a monoazo pigment containing a metal element having a specific structure, and a naphthol AS pigment having a specific structure as colorants, wherein the total content of the quinacridone pigment and the monoazo pigment containing a metal element is 50 to 90% by mass of the entire colorant.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-169697

[0005] Patent Document 2: Japanese Patent Application Laid-Open No. 2018-173558 Summary of the Invention

[0006] An object of the present invention is to provide a toner for developing electrostatic images having better color development properties than when the IBr is less than 1 kcps or exceeds 30 kcps or the IS / IBr is less than 0.005 or exceeds 1.2.

[0007] Means for solving the above-mentioned problems include the following.

[0008] <1>

[0009] A toner for developing electrostatic images, comprising toner particles containing a resin and a colorant,

[0010] When the Net intensity of the Br element in the toner particles measured by fluorescent X-ray analysis is defined as Ibr and the Net intensity of the S element measured by fluorescent X-ray analysis is defined as IS,

[0011] Ibr is 1kcps or more and 30kcps or less, and

[0012] IS / Ibr is 0.005 or more and 1.2 or less.

[0013] <2>

[0014] The electrostatic image developing toner according to <1>, wherein

[0015] When the Net intensity of the O element in the toner particles measured by fluorescent X-ray analysis is defined as IO, IBr / IO is 4.76 or more and 333 or less.

[0016] <3>

[0017] The electrostatic image developing toner according to <1> or <2>, wherein

[0018] IBr is 10 kcps or more and 25 kcps or less.

[0019] <4>

[0020] The electrostatic image developing toner according to <3>, wherein

[0021] IS / IBr is 0.03 or more and 0.06 or less.

[0022] <5>

[0023] The electrostatic image developing toner according to any one of <2> to <4>, wherein

[0024] IBr / IO is 83.3 or more and 143 or less.

[0025] <6>

[0026] The electrostatic image developing toner according to any one of <1> to <5>, wherein

[0027] The resin includes a polyester resin.

[0028] <7>

[0029] The electrostatic image developing toner according to any one of <1> to <6>, wherein

[0030] The toner particles contain a releasing agent comprising an ester wax.

[0031] <8>

[0032] An electrostatic image developer comprising the electrostatic image developing toner according to any one of <1> to <7>.

[0033] <9>

[0034] A toner cartridge containing the electrostatic image developing toner described in any one of <1> to <7>,

[0035] The image forming apparatus is mounted and removed from the image forming apparatus.

[0036] <10>

[0037] A process cartridge comprising a developing device that contains the electrostatic image developer described in <8> and develops an electrostatic image formed on a surface of an image holding member into a toner image using the electrostatic image developer.

[0038] The process cartridge is attachable to and detachable from the image forming apparatus.

[0039] <11>

[0040] An image forming apparatus comprising:

[0041] Image holding body;

[0042] a charging device for charging the surface of the image holding member;

[0043] an electrostatic image forming device for forming an electrostatic image on the charged surface of the image holding member;

[0044] a developing device that accommodates the electrostatic image developer described in <8> and develops the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer;

[0045] a transfer device that transfers the toner image formed on the surface of the image holding member to the surface of a recording medium; and

[0046] The fixing device fixes the toner image transferred onto the surface of the recording medium.

[0047] <12>

[0048] An image forming method comprising:

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

[0050] an electrostatic image forming step of forming an electrostatic image on the charged surface of the image holding member;

[0051] a developing step of developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer described in <8>;

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

[0053] The fixing step fixes the toner image transferred onto the surface of the recording medium.

[0054] Effects of the Invention

[0055] According to the invention <1>, there is provided a toner for developing electrostatic images having better color development properties than when the IBr is less than 1 kcps or exceeds 30 kcps or the IS / IBr is less than 0.005 or exceeds 1.2.

[0056] According to the invention <2>, there is provided a toner for developing electrostatic images having better color development properties than when IBr / IO is less than 4.76 or exceeds 333.

[0057] According to the invention according to <3>, there is provided a toner for developing electrostatic images having better color development properties than a toner having an IBr of less than 10 kcps or exceeding 25 kcps.

[0058] According to the invention according to <4>, there is provided a toner for developing an electrostatic image having better color development properties than when IS / IBr is less than 0.03 or exceeds 0.06.

[0059] According to the invention according to <5>, there is provided a toner for developing an electrostatic image having better color development properties than when IBr / IO is less than 83.3 or exceeds 143.

[0060] According to the invention according to <6>, there is provided a toner for developing an electrostatic image having better color development properties than a toner in which the resin is composed of a styrene acrylic resin.

[0061] According to the invention according to <7>, there is provided a toner for developing electrostatic images having better color development properties than a toner containing a release agent composed of paraffin wax.

[0062] According to the inventions described in <8>, <9>, <10>, <11> or <12>, there is provided an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus or an image forming method, which makes it easier to obtain an image with high saturation than when using an electrostatic image developing toner having an IBr of less than 1 kcps or exceeding 30 kcps or an IS / IBr of less than 0.005 or exceeding 1.2. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0064] Figure 1FIG. 1 is a schematic structural diagram showing an example of an image forming apparatus according to the present embodiment;

[0065] Figure 2 This is a schematic structural diagram showing an example of a process cartridge that is attached to and detached from the image forming apparatus according to the present embodiment.

[0066] Explanation of symbols

[0067] 1Y, 1M, 1C, 1K - photoreceptor (an example of an image holding member), 2Y, 2M, 2C, 2K - charging roller (an example of a charging device), 3 - exposure device (an example of an electrostatic image forming device), 3Y, 3M, 3C, 3K - laser beam, 4Y, 4M, 4C, 4K - developing device (an example of a developing device), 5Y, 5M, 5C, 5K - primary transfer roller (an example of a primary transfer device), 6Y, 6M, 6C, 6K - photoreceptor cleaning device (an example of a cleaning device), 8Y, 8M, 8C, 8K - toner cartridge, 10Y, 10M, 10C, 10K - image forming unit, 20 - intermediate transfer belt (an example of an intermediate transfer member), 22 - drive roller, 24 - backup roller, 26 - Secondary transfer roller (an example of a secondary transfer device), 28-fixing device (an example of a fixing device), 30-intermediate transfer body cleaning device, 107-photoreceptor (an example of an image holding body), 108-charging roller (an example of a charging device), 109-exposure device (an example of an electrostatic image forming device), 111-developing device (an example of a developing device), 112-transfer device (an example of a transfer device), 113-photoreceptor cleaning device (an example of a cleaning device), 115-fixing device (an example of a fixing device), 116-mounting guide, 117-housing, 118-opening for exposure, 200-processing box, 300-recording paper (an example of a recording medium), P-recording paper (an example of a recording medium). DETAILED DESCRIPTION

[0068] Hereinafter, embodiments of the present invention will be described. These descriptions and examples illustrate the embodiments and do not limit the scope of the embodiments.

[0069] In the present invention, a numerical range expressed using “to” indicates a range including the numerical values ​​before and after “to” as the minimum value and the maximum value, respectively.

[0070] In the numerical ranges described in stages in the present invention, the upper limit or lower limit of one numerical range may be replaced by the upper limit or lower limit of another numerical range described in stages. Furthermore, in the numerical ranges described in the present invention, the upper limit or lower limit of the numerical range may also be replaced by the value shown in the Examples.

[0071] In the present invention, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes as long as the intended purpose of the process can be achieved.

[0072] In the present invention, when the embodiments are described with reference to the drawings, the structures of the embodiments are not limited to those shown in the drawings. Furthermore, the sizes of the components in the drawings are conceptual, and the relative sizes of the components are not limited thereto.

[0073] In the present invention, each component may include multiple corresponding substances. In the present invention, when referring to the amount of each component in the composition, if multiple substances corresponding to each component are present in the composition, unless otherwise specified, it refers to the total amount of the multiple substances present in the composition.

[0074] In the present invention, multiple types of particles corresponding to each component may be included. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component refers to the value for the mixture of the multiple types of particles present in the composition unless otherwise specified.

[0075] In the present invention, “(meth)acrylic acid” means at least one of acrylic acid and methacrylic acid, and “(meth)acrylate” means at least one of acrylate and methacrylate.

[0076] [Toner for electrostatic image development]

[0077] The electrostatic image developing toner involved in this embodiment (hereinafter also simply referred to as "toner") includes toner particles containing a resin and a colorant. When the Net intensity of the Br element in the toner particles measured by fluorescent X-ray analysis is set to Ibr and the Net intensity of the S element measured by fluorescent X-ray analysis is set to IS, Ibr is greater than or equal to 1 kcps and less than or equal to 30 kcps, and IS / Ibr is greater than or equal to 0.005 and less than or equal to 1.2.

[0078] In the present embodiment, when IBr and IS / IBr are within the above ranges, the color development property becomes good. The reason for this is not clear, but is presumed as follows.

[0079] In a toner comprising toner particles containing a resin and a colorant, if the colorant is unevenly distributed within the toner particles, color development tends to decline. However, if the colorant is well dispersed, color development tends to improve. Furthermore, using a toner with good color development tends to produce images with high saturation.

[0080] Furthermore, it is believed that in toner particles containing a moderate amount of bromide ions, the repulsive force of the bromide ions allows various components, such as the colorant, to be well dispersed during the toner particle production process. On the other hand, if the amount of bromide ions present is high and the repulsive force of the bromide ions is too strong, the colorant may be unevenly distributed and easily aggregated.

[0081] Furthermore, it is believed that in toner particles containing a moderate amount of sulfide ions, the repulsive force between the sulfide ions and the bromide ions during the toner particle production process allows the bromide ions to be well dispersed, further enhancing the colorant dispersion effect of the bromide ions. On the other hand, if the amount of sulfide ions present is excessive relative to the amount of bromide ions present, the repulsive force between the sulfide ions and the bromide ions becomes excessively strong, making it difficult for the bromide ions to disperse, and sometimes reducing the colorant dispersion effect of the bromide ions.

[0082] In contrast, in the present embodiment, IBr and IS / IBr are within the above ranges. That is, in the present embodiment, bromide ions are present appropriately in the toner particles, and the amount of sulfide ions relative to the amount of bromide ions is also appropriate.

[0083] Therefore, in this embodiment, the colorant dispersion effect due to bromide ions is more easily achieved than when IBr is less than the above range or when IS / IBr is less than the above range. Furthermore, compared to when IBr is greater than the above range, aggregation of the colorant due to excessive repulsion from bromide ions is suppressed. Compared to when IS / IBr is greater than the above range, the repulsion between sulfide ions and bromide ions is less intense, making the colorant dispersion effect due to bromide ions more easily achieved.

[0084] Based on the above reasons, it is estimated that the toner of this embodiment has good color development properties.

[0085] <Net Strength of Each Element>

[0086] The method for measuring the Net intensity of each element in the toner particles by fluorescent X-ray analysis is as follows.

[0087] Using a compression molding machine, 140 mg of toner particles were compressed under a load of 10 tons for 60 seconds to produce a 10 mm diameter disc. This disc was used as a sample and analyzed for all elements using a scanning fluorescent X-ray analyzer (ZSX Primus II, manufactured by Rigaku Corporation) under the following measurement conditions. The Net intensity (unit: kilo counts per second, kcps) of each element was determined. Furthermore, when performing the above measurement on an external additive toner in which the external additive is attached to the toner particles, the measurement can be performed using toner particles from which the external additive has been removed. Alternatively, the measurement can be performed using the external additive toner directly instead of the toner particles, and the Net intensity of each element in the toner particles can be calculated by correcting for the effects of the external additive.

[0088] -Measurement conditions-

[0089] Tube voltage: 40kV

[0090] Tube current: 70mA

[0091] ·Cathode: Rhodium

[0092] Measurement time: 15 minutes

[0093] Analytical diameter: Diameter

[0094] As described above, the IBr is 1 kcps to 30 kcps, and from the viewpoint of obtaining good color development, it is, for example, preferably 10 kcps to 25 kcps, and more preferably 13 kcps to 23 kcps.

[0095] It is speculated that when IBr is at least the lower limit, the repulsive force of bromide ions improves the dispersibility of the colorant, resulting in improved color development of the toner. Furthermore, it is speculated that when IBr is at most the upper limit, aggregation of the colorant caused by excessive repulsive force of bromide ions is suppressed, resulting in improved color development of the toner.

[0096] IBr is the Net intensity measured by fluorescent X-ray analysis and indicates the amount of Br contained throughout the toner particles (mainly within them). Therefore, one method for controlling IBr within the above range is to add a compound containing bromine atoms (hereinafter also referred to as a "bromine-containing compound") during the toner particle production process and adjust the amount of addition. For example, the bromine-containing compound may be a coagulant used when producing toner particles by the coagulation method described below.

[0097] Examples of bromine-containing compounds include quaternary ammonium salts such as ammonium bromide, decyltrimethylammonium bromide, tetramethylammonium bromide, tetradecylammonium bromide, and alkylbenzyldimethylammonium bromide; iron bromide; zinc bromide; alkali metal bromides such as lithium bromide, sodium bromide, potassium bromide, rubidium bromide, cesium bromide, and francium bromide; and alkaline earth metal bromides such as beryllium bromide, magnesium bromide, strontium bromide, barium bromide, and radium bromide. From the perspective of good dispersion of various components such as the colorant, the bromine-containing compound is preferably a quaternary ammonium salt, and more preferably a tetraalkylammonium bromide.

[0098] The IS is, for example, in the range of 0.075 kcps to 18 kcps. From the viewpoint of obtaining good color rendering properties, the IS is preferably 0.3 kcps to 10 kcps, and more preferably 0.5 kcps to 3 kcps.

[0099] As described above, IS / IBr is 0.005 or more and 1.2 or less. From the viewpoint of obtaining good color development properties, it is, for example, preferably 0.015 or more and 0.08 or less, and more preferably 0.03 or more and 0.06 or less.

[0100] It is speculated that when IS / IBr is at least the lower limit, the repulsive force between sulfide ions and bromide ions allows bromide ions to be well dispersed, further enhancing the colorant dispersion effect of bromide ions, thereby improving the color development properties of the toner. Furthermore, it is speculated that when IS / IBr is at most the upper limit, the difficulty in dispersing bromide ions due to excessive repulsive force between sulfide ions and bromide ions is suppressed, thereby improving the color development properties of the toner.

[0101] One method for controlling IS is to add a compound containing sulfur atoms (hereinafter also referred to as a "sulfur-containing compound") during the toner particle production process and adjust the amount of addition. For example, the sulfur-containing compound may be a surfactant used when producing toner particles by the coagulation method described below.

[0102] Examples of the sulfur-containing compound include sodium alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate and sodium polyoxyethylene arylphenyl ether sulfonate; sodium polyoxyethylene alkyl ether sulfonate, etc. From the viewpoint of dispersibility of the colorant, sodium alkylbenzenesulfonate is preferred as the sulfur-containing compound.

[0103] When the Net intensity of the O element is set to IO, as IO, for example, the range of 0.01 kcps to 4.0 kcps can be cited. From the viewpoint of obtaining good color rendering, it is preferably 0.04 kcps to 3.0 kcps, and more preferably 0.1 kcps to 1.0 kcps.

[0104] From the viewpoint of obtaining good color development, IBr / IO is, for example, preferably 4.76 or more and 333 or less, more preferably 83.3 or more and 143 or less, and still more preferably 90 or more and 120 or less.

[0105] When IBr / IO is within the above range, the color development of the toner becomes good. Although the reason is not clear, it is speculated as follows. For example, when the resin contained in the toner particles has an ester bond, the source of the O element present in the toner particles can mainly be the oxygen atoms of the ester bond contained in the resin. And, for example, when the toner particles contain a release agent having an ester bond, the oxygen atoms of the ester bond contained in the release agent can also become the source of the O element. Hereinafter, the component that will become the source of the O element is also referred to as the "O element source component". If IBr / IO is above the above lower limit, bromide ions are fully present relative to oxygen atoms, so the bromide ions are repelled by the negative polarity of the oxygen atoms contained in the O element source component, and the O element source component becomes easy to disperse. Moreover, it is speculated that by making the O element source component (i.e., resin, etc.) easy to disperse, the dispersibility of the colorant is also improved, and the color development of the toner becomes good. Furthermore, it is speculated that if IBr / IO is below the above-mentioned upper limit value, the uneven distribution of the O-element-derived components caused by the excessive presence of bromide ions relative to oxygen atoms is suppressed, and the decrease in the dispersibility of the colorant caused by the uneven distribution of the O-element-derived components (i.e., resin, etc.) is also suppressed, thereby improving the color rendering properties of the toner.

[0106] Methods for controlling IO include a method of using a resin containing oxygen atoms as the resin and adjusting the content of the resin; a method of adding a release agent containing oxygen atoms and adjusting the amount of addition; a method of adding an oxidizing agent such as ozone to introduce oxygen atoms into the resin and adjusting the amount of addition (i.e., adjusting the amount of oxygen atoms introduced); combinations of these, etc.

[0107] As the resin containing oxygen atoms, polyester resins, acrylic resins, styrene acrylic resins, epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, etc. can be cited. The resin containing oxygen atoms can also be a resin with a structure having a high internal oxygen ratio such as polyvinyl alcohol. From the viewpoint of obtaining good color development, among these, the resin containing oxygen atoms, for example, preferably has an ester bond, more preferably has an ester bond on the main chain, and further preferably a polyester resin. From the viewpoint of obtaining good color development by controlling IBr / IO within the range, the resin, for example, preferably contains at least one selected from the group consisting of polyester resins and styrene acrylic resins, more preferably contains at least one polyester resin. In order to easily control IBr / IO, the resin can contain both polyester resin and styrene acrylic resin.

[0108] Examples of oxygen-containing release agents include ester waxes. Among ester waxes, pentaerythritol alkyl esters are preferred for achieving good color development. To facilitate control of the IBr / IO ratio, the release agent may contain two or more release agents. Combinations of two or more release agents include, for example, a combination of an ester wax and a hydrocarbon wax.

[0109] The oxidizing agent is not particularly limited as long as it is a compound that introduces oxygen atoms into a resin or the like, and examples thereof include ozone.

[0110] Hereinafter, the toner according to this embodiment will be described in detail.

[0111] The toner according to this embodiment includes toner particles. The toner according to this embodiment may include an external additive.

[0112] (Toner particles)

[0113] For example, the toner particles include resin, a colorant, a release agent, other additives, and the like.

[0114] -Resin-

[0115] Examples of the resin include vinyl resins composed of homopolymers of monomers such as styrenes (e.g., styrene, p-chlorostyrene, α-methylstyrene, etc.), (meth)acrylates (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), and olefins (e.g., ethylene, propylene, butadiene, etc.), or copolymers obtained by combining two or more of these monomers.

[0116] Examples of the resin include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosins; mixtures thereof with the vinyl resins; and graft polymers obtained by polymerizing vinyl monomers in the presence of the resins.

[0117] These resins may be used alone or in combination of two or more.

[0118] As the resin, for example, polyester resin is preferable.

[0119] Examples of the polyester resin include known amorphous polyester resins. A crystalline polyester resin may be used in combination with the amorphous polyester resin. The crystalline polyester resin is preferably used in an amount of 2% by mass to 40% by mass (e.g., more preferably 2% by mass to 20% by mass) relative to the total resin content.

[0120] The "crystallinity" of a resin refers to the presence of a clear endothermic peak in differential scanning calorimetry (DSC) rather than a step-like change in endothermic value. Specifically, it refers to the half-width of the endothermic peak being within 10°C when measured at a heating rate of 10°C / min.

[0121] On the other hand, the "amorphous nature" of a resin means that the half-value width exceeds 10°C, the endothermic value shows a step-like change, or a clear endothermic peak cannot be confirmed.

[0122] Amorphous polyester resin

[0123] Examples of the amorphous polyester resin include polycondensates of polycarboxylic acids and polyols. A commercially available amorphous polyester resin may be used, 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, and sebacic acid), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, and naphthalene dicarboxylic acid), anhydrides thereof, and lower (e.g., having 1 to 5 carbon atoms) alkyl esters thereof. Among these, aromatic dicarboxylic acids are preferred as the polycarboxylic acid.

[0125] Regarding polycarboxylic acids, trivalent or higher carboxylic acids having a cross-linked structure or a branched structure may be used in combination with dicarboxylic acids. Examples of trivalent or higher carboxylic acids 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, aromatic diols and alicyclic diols are preferred as the polyol, and aromatic diols are more preferred.

[0128] As the polyol, a trivalent or higher polyol having a cross-linked structure or a branched structure may be used in combination with the 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, for example, 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), more specifically, according to the "extrapolated glass transition onset temperature" method described in JIS K 7121-1987 "Plastics - Determination of Transition Temperatures".

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

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

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

[0135] In addition, the weight average molecular weight and number average molecular weight were measured by gel permeation chromatography (GPC). In the molecular weight measurement based on GPC, a GPC HLC-8120GPC manufactured by TOSOH CORPORATION was used as the measuring apparatus, and a column TSKgel SuperHM-M (15 cm) manufactured by TOSOH CORPORATION was used in a THF solvent. The weight average molecular weight and number average molecular weight were calculated using a molecular weight calibration curve prepared based on the measurement results and using a monodisperse polystyrene standard sample.

[0136] The amorphous polyester resin is obtained by a known production method. Specifically, for example, the polymerization temperature is set to 180° C. to 230° C., and the pressure in the reaction system is reduced as needed to allow the reaction to proceed while removing water or alcohol generated during condensation.

[0137] Furthermore, if the raw monomers are insoluble or incompatible under the reaction temperature conditions, a high-boiling-point solvent may be added as a cosolvent to dissolve them. In this case, the polycondensation reaction is carried out while distilling off the cosolvent. If a poorly miscible monomer is present, for example, the poorly miscible monomer can be pre-condensed with an acid or alcohol intended to be polycondensed with the monomer, 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. A commercially available crystalline polyester resin may be used, or a synthetic resin may be used.

[0140] Here, in order to easily form a crystal structure, the crystalline polyester resin is preferably a polycondensate of a polymerizable monomer having a linear aliphatic group, rather than a polycondensate of 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), anhydrides thereof, or lower (e.g., having 1 to 5 carbon atoms) alkyl esters thereof.

[0142] Regarding polycarboxylic acids, trivalent or higher carboxylic acids having a cross-linked structure or a branched structure may be used in combination with dicarboxylic acids. Examples of trivalent carboxylic acids include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), their anhydrides, or their lower (e.g., carbon number 1 to 5) alkyl esters.

[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 portion with 7 to 20 carbon atoms). Examples of the aliphatic diol 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-eicosanediol. Among these, preferred aliphatic diols include 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol.

[0146] Regarding the polyol, a trivalent or higher alcohol having a cross-linked structure or a branched structure may be used in combination with the diol. 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, regarding the polyol, for example, the content of the aliphatic diol is preferably 80 mol% or more, and more preferably 90 mol% or more.

[0149] The melting temperature of the crystalline polyester resin is, for example, preferably 50° C. or higher and 100° C. or lower, more preferably 55° C. or higher and 90° C. or lower, and further preferably 60° C. or higher and 85° C. or lower.

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

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

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

[0153] When the resin contains a polyester resin, the content of the polyester resin relative to the entire resin is, for example, 20% by mass or more and 100% by mass or less, and preferably 40% by mass or more and 100% by mass.

[0154] Examples of the resin include vinyl resins.

[0155] The vinyl resin will be described.

[0156] Examples of the vinyl 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.), and olefins (e.g., ethylene, propylene, butadiene, etc.), or copolymers obtained by combining two or more of these monomers.

[0157] These vinyl resins may be used alone or in combination of two or more.

[0158] As the vinyl resin, for example, styrene acrylic resin is preferred from the viewpoint of excellent environmental stability of toner charging.

[0159] Styrene acrylic resin is a copolymer formed by copolymerizing at least a styrene-based monomer (a monomer having a styrene skeleton) and a (meth)acrylic monomer (a monomer having a (meth)acryloyl group, preferably a monomer having a (meth)acryloyloxy group). Styrene acrylic resins include, for example, copolymers of styrene-based monomers and the aforementioned (meth)acrylate monomers. The acrylic resin portion of a styrene acrylic resin is a partial structure formed by polymerizing either an acrylic monomer or a methacrylic monomer. Furthermore, the term "(meth)acrylic" encompasses both "acrylic" and "methacrylic."

[0160] Specific examples of styrene-based monomers include styrene, alkyl-substituted styrenes (e.g., α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, etc.), halogen-substituted styrenes (e.g., 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, etc.), and vinylnaphthalene. These styrene-based monomers may be used alone or in combination of two or more.

[0161] Among these, as the styrene-based monomer, styrene is preferred, for example, from the viewpoint of reactivity, easiness of reaction controllability, and availability.

[0162] Examples of the (meth)acrylic acid monomers include (meth)acrylic acid and (meth)acrylic acid esters. Examples of the (meth)acrylic acid esters include (meth)acrylic acid alkyl esters (e.g., methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-octadecyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isopentyl (meth)acrylate, and n-octadecyl (meth)acrylate). (meth)acrylate, pentyl (meth)acrylate, neopentyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, etc.), aryl (meth)acrylate (for example, phenyl (meth)acrylate, biphenyl (meth)acrylate, diphenylethyl (meth)acrylate, tert-butylphenyl (meth)acrylate, terphenyl (meth)acrylate, etc.), dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, β-carboxyethyl (meth)acrylate, (meth)acrylamide, etc. The (meth)acrylic monomer may be used alone or in combination of two or more.

[0163] Among these (meth)acrylates in the (meth)acrylic monomers, (meth)acrylates having an alkyl group with 2 to 14 carbon atoms (for example, preferably 2 to 10 carbon atoms, more preferably 3 to 8 carbon atoms) are preferred from the viewpoint of improving the fixing properties of the toner. Among them, n-butyl (meth)acrylate is preferred, and n-butyl acrylate is particularly preferred.

[0164] The copolymerization ratio of the styrene-based monomer to the (meth)acrylic monomer (mass basis, styrene-based monomer / (meth)acrylic monomer) is not particularly limited, but is preferably 98 / 2 to 60 / 40.

[0165] From the viewpoint of improving the fixing property of the toner, the glass transition temperature (Tg) of the styrene acrylic resin is, for example, preferably 40° C. or higher and 75° C. or lower, and more preferably 50° C. or higher and 65° C. or lower.

[0166] Here, the glass transition temperature of a resin is determined from a DSC curve obtained by differential scanning calorimetry (DSC). More specifically, the glass transition temperature of a resin is determined according to the "extrapolated glass transition onset temperature" method described in JIS K 7121:1987, "Plastics - Determination of Transition Temperatures."

[0167] From the viewpoint of storage stability of the toner, the weight average molecular weight of the styrene acrylic resin is, for example, preferably 5,000 or more and 200,000 or less, more preferably 10,000 or more and 100,000 or less, and particularly preferably 20,000 or more and 80,000 or less.

[0168] The method for preparing the styrene acrylic resin is not particularly limited, and various polymerization methods (e.g., solution polymerization, precipitation polymerization, suspension polymerization, bulk polymerization, emulsion polymerization, etc.) can be applied. Furthermore, the polymerization reaction can be carried out using known procedures (e.g., batch, semi-continuous, continuous, etc.).

[0169] The toner particles preferably contain at least one selected from the group consisting of a polyester resin and a vinyl resin, but may contain both a polyester resin and a vinyl resin, or may contain only one of them. When the toner particles contain both a polyester resin and a vinyl resin, the toner particles may contain both as a binder resin, or may contain one of the polyester resin and the vinyl resin as a binder resin and the other as resin particles. When the toner particles contain either a polyester resin or a vinyl resin as the resin particles, the resin particles may have a cross-linked structure.

[0170] When the toner particles contain both a polyester resin and a vinyl resin, the mass ratio C of the polyester resin to the vinyl resin may be, for example, 0.7 to 10, 1 to 6, or 1 to 5.

[0171] Examples of the resin containing both a polyester resin and a vinyl resin include a resin containing a styrene acrylic resin and a polyester resin.

[0172] Here, the coexistence of styrene acrylic resin and polyester resin can be achieved not only by mixing the individual resins, but also by coexisting as a hybrid resin having chemically bonded styrene acrylic resin segments and polyester resin segments (so-called styrene acrylic modified polyester resin). Specifically, a polyester monomer having an unsaturated structure, such as fumaric acid or succinic acid, or a resin containing such a monomer structure, is used as a prepolymer and polymerized with a vinyl monomer, such as styrene or acrylic acid, to obtain a hybrid resin.

[0173] When a hybrid resin (so-called styrene-acrylic modified polyester resin) is used, the mass ratio C of the polyester resin to the vinyl resin is measured and calculated as the mass ratio of the polyester segment of the hybrid resin to the vinyl resin segment (e.g., styrene-acrylic resin segment). Furthermore, when a hybrid resin, a vinyl resin (e.g., styrene-acrylic resin), and a polyester resin are used in combination, the mass ratio C is measured and calculated as the mass ratio of the sum of the polyester resin segment and the polyester resin of the hybrid resin to the sum of the vinyl resin segment and the vinyl resin of the hybrid resin.

[0174] The content of the resin is, for example, preferably 40% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 93% by mass or less, and further preferably 60% by mass or more and 93% by mass or less, based on the entire toner particles.

[0175] -Colorant-

[0176] Examples of the colorant include carbon black, chrome yellow, Hansa yellow, benzidine yellow, vat yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, magenta carmine, permanent red, brilliant carmine 3B, brilliant carmine 6B, Dupont Oil Red, pyrazolone red, litho red, rhodamine B Lake, Red Lake C, pigment red, rose Bengal, aniline blue, ultramarine blue, copper oil blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate; and various dyes such as acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, nigrosine-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, and thiazole-based dyes.

[0177] The coloring agents may be used alone or in combination of two or more.

[0178] The colorant may be a surface-treated colorant as needed, and may be used in combination with a dispersant. Furthermore, multiple colorants may be used in combination.

[0179] The content of the colorant is, for example, preferably 1 mass % or more and 30 mass % or less, and more preferably 3 mass % or more and 15 mass % or less, based on the total mass of the toner particles.

[0180] -Release agent-

[0181] Examples of the release agent include hydrocarbon waxes, natural waxes such as carnauba wax, rice wax, and candelilla wax, synthetic or mineral / petroleum waxes such as montan wax, and ester waxes such as fatty acid esters and montanic acid esters. The release agent is not limited thereto.

[0182] The release agent is preferably an ester wax, for example. Ester wax is a wax having an ester bond. The ester wax may be any of monoesters, diesters, triesters, and tetraesters, and known natural or synthetic ester waxes may be used. Examples of the ester wax include ester compounds of higher fatty acids (such as fatty acids having 10 or more carbon atoms) and monovalent or polyvalent aliphatic alcohols (such as aliphatic alcohols having 8 or more carbon atoms).

[0183] Examples of ester waxes include ester compounds of higher fatty acids (caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, oleic acid, and montanic acid) and alcohols (monohydric alcohols such as methanol, ethanol, propanol, isopropyl alcohol, butanol, octanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, and oleyl alcohol; and polyhydric alcohols such as glycerol, ethylene glycol, propylene glycol, sorbitol, and pentaerythritol). Specific examples include carnauba wax, rice bran wax, candelilla wax, jojoba oil, wood wax, beeswax, white wax, lanolin, and montanic acid ester waxes.

[0184] The melting temperature of the release agent is, for example, preferably 50° C. or higher and 110° C. or lower, and more preferably 60° C. or higher and 105° C. or lower.

[0185] The melting temperature is determined based on the “melting peak temperature” described in the method for determining the melting temperature in JIS K7121-1987 “Determination of Transition Temperatures of Plastics” from a DSC curve obtained by differential scanning calorimetry (DSC).

[0186] The content of the releasing agent is, for example, preferably 1 mass % or more and 20 mass % or less, and more preferably 3 mass % or more and 15 mass % or less, based on the total mass of the toner particles.

[0187] -Other additives-

[0188] Examples of other additives include well-known additives such as magnetic materials, charge control agents, and inorganic powders. These additives are contained in the toner particles as internal additives.

[0189] The toner particles may contain a bromine-containing compound as a source of the Br element. Specific examples of the bromine-containing compound are described above. The content of the bromine-containing compound relative to the total toner particles may be, for example, in the range of 0.04 mass% to 0.4 mass%, 0.05 mass% to 0.3 mass%, or 0.06 mass% to 0.25 mass%.

[0190] The toner particles may contain a sulfur-containing compound as a source of element S. Specific examples of the sulfur-containing compound are described above. The content of the sulfur-containing compound relative to the total toner particles may be, for example, in the range of 0.001 mass % to 0.02 mass %, 0.002 mass % to 0.015 mass %, or 0.003 mass % to 0.012 mass %.

[0191] - Characteristics of toner particles, etc. -

[0192] The toner particles may be toner particles of a single-layer structure, or may be toner particles of a so-called core-shell structure composed of a core (core particle) and a coating layer (shell layer) that covers the core.

[0193] Here, the toner particles with a core-shell structure preferably include, for example, a core portion containing a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer containing a binder resin.

[0194] The volume average particle diameter (D50v) of the toner particles is, for example, preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

[0195] Various average particle sizes and various particle size distribution indices of the toner particles are measured using Coulter Multisizer II (manufactured by Beckman Coulter) and ISOTON-II (manufactured by Beckman Coulter) as the electrolyte.

[0196] During measurement, 0.5 mg to 50 mg of the sample is added as a dispersant to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate), which is then added to 100 ml to 150 ml of the electrolyte.

[0197] The electrolyte solution containing the sample was dispersed for 1 minute using an ultrasonic disperser, and the particle size distribution of particles with a diameter of 2 μm to 60 μm was measured using a Coulter Multisizer II with a pore diameter of 100 μm. 50,000 particles were sampled.

[0198] For the particle size range (interval) divided based on the particle size distribution to be measured, the volume cumulative distribution and the number cumulative distribution are respectively drawn from the smaller diameter side, and the particle size that will become 16% of the cumulative is defined as the volume particle size D16v and the number particle size D16p, the particle size that will become 50% of the cumulative is defined as the volume average particle size D50v and the cumulative number average particle size D50p, and the particle size that will become 84% of the cumulative is defined as the volume particle size D84v and the number particle size D84p.

[0199] Use them, by (D84v / D16v) 1 / 2 Calculate the volume particle size distribution index (GSDv) from (D84p / D16p) 1 / 2 Calculate the particle size distribution index (GSDp).

[0200] The average circularity of the toner particles is, for example, preferably 0.90 or more and 1.00 or less, and more preferably 0.92 or more and 0.98 or less.

[0201] The average circularity of the toner particles is calculated as (circle-equivalent circumference) / (circumference) [(circumference of a circle having the same projected area as the particle image) / (circumference of the particle projected image)]. Specifically, it is a value measured by the following method.

[0202] First, the toner particles to be measured were collected by suction, forming a flattened flow. This flow was then momentarily stroboscoped to capture a still image of the particles. This image was then analyzed using a flow particle image analyzer (FPIA-3000, manufactured by Sysmex Corporation) to determine the average circularity. The number of samples sampled for the calculation was 3500.

[0203] When the toner contains an external additive, the toner (developer) to be measured is dispersed in water containing a surfactant and then subjected to ultrasonic treatment to obtain toner particles from which the external additive has been removed.

[0204] (External additives)

[0205] Examples of external additives include inorganic particles. Examples of such inorganic particles include SiO2, TiO2, Al2O3, SrTiO3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, and K2O·(TiO2). n , Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, etc.

[0206] As the surface of the inorganic particles of the external additive, for example, hydrophobization treatment is preferably implemented.Hydrophobic treatment is carried out, for example, by impregnating the inorganic particles in a hydrophobization treatment agent.The hydrophobization treatment agent is not particularly limited, and for example, silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents, etc. can be cited. They can be used alone or in combination of two or more.

[0207] The amount of the hydrophobizing agent is usually, for example, 1 part by mass or more and 10 parts by mass or less relative to 100 parts by mass of the inorganic particles.

[0208] Examples of external additives include resin particles (polystyrene, polymethyl methacrylate (PMMA), melamine resin, and the like), cleaning activators (for example, metal salts of higher fatty acids such as zinc stearate, and particles of fluorine-based high molecular weight substances).

[0209] The amount of the external additive added 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 6.0% by mass or less, based on the toner particles.

[0210] (Toner Manufacturing Method)

[0211] Next, a method for producing a toner according to this embodiment will be described.

[0212] The toner according to this embodiment is obtained by manufacturing toner particles and then adding an external additive to the toner particles.

[0213] Toner particles can be produced by any of dry methods (e.g., kneading and pulverization methods) or wet methods (e.g., coagulation, suspension polymerization, and dissolution suspension methods). The method for producing toner particles is not particularly limited to these methods, and well-known methods may also be used.

[0214] Among these, for example, it is preferable to obtain toner particles by an aggregation method.

[0215] Specifically, for example, when toner particles are produced by an aggregation method, the toner particles are produced through the following steps:

[0216] a step of mixing a first resin particle dispersion in which first resin particles serving as a binder resin are dispersed, a colorant dispersion in which a colorant is dispersed, and a release agent particle dispersion in which particles of a release agent (hereinafter also referred to as "release agent particles") are dispersed, and agglomerating the particles and the colorant in the obtained dispersion to form first aggregated particles (a first aggregated particle forming step);

[0217] After obtaining a first aggregated particle dispersion in which first aggregated particles are dispersed, second resin particles serving as a binder resin are added to the first aggregated particle dispersion to aggregate the second resin particles on surfaces of the first aggregated particles to form second aggregated particles (a second aggregated particle forming step); and

[0218] A step of heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and unify the second aggregated particles to form toner particles (fusing and unifying step).

[0219] Furthermore, although the present aggregation method is described as a method for producing toner particles containing a binder resin, a colorant, and a release agent, the colorant and the release agent are components contained in the toner particles as necessary.

[0220] As described above, methods for controlling IBr within the above range include adding a bromine-containing compound during the toner particle production process and adjusting the amount of addition. When producing toner particles by an aggregation method, for example, the bromine-containing compound is preferably added in at least one of the first aggregated particle formation step and the second aggregated particle formation step, with addition of the bromine-containing compound in the first aggregated particle formation step being more preferred. The amount of the bromine-containing compound added, relative to 100 parts by mass of the total components constituting the toner particles, can be, for example, 0.5 parts by mass or more and 3.0 parts by mass or less, 1 part by mass or more and 2.5 parts by mass or less, or 1.5 parts by mass or more and 2.0 parts by mass or less.

[0221] As mentioned above, one method for controlling IS is to add a sulfur-containing compound during the toner particle production process and adjust the amount of addition. When producing toner particles by an agglomeration method, for example, the sulfur-containing compound is preferably added in at least one of the first agglomerated particle formation step and the second agglomerated particle formation step, with the addition of the sulfur-containing compound in the first agglomerated particle formation step being more preferred. The amount of the sulfur-containing compound added, relative to 100 parts by mass of the total components constituting the toner particles, can be, for example, 0.003% to 0.03% by mass, 0.005% to 0.02% by mass, or 0.008% to 0.012% by mass.

[0222] Furthermore, as described above, one method of controlling IO includes adding an oxidizing agent such as ozone and adjusting the amount thereof. When toner particles are produced by an agglomeration method, for example, the oxidizing agent is preferably added in at least one of the first agglomerated particle forming step and the second agglomerated particle forming step, and more preferably, the oxidizing agent is added in the first agglomerated particle forming step. When ozone is used as the oxidizing agent, for example, it is preferably added in the form of ozone water, and more preferably, it is added in the form of ozone water having a concentration of 2 mass ppm or more and 8 mass ppm or less. The amount of ozone water added, relative to a total of 100 mass parts of the components constituting the toner particles, can be, for example, 0.005 mass parts or more and 18 mass parts or less, or can be in the range of 0.008 mass parts or more and 15 mass parts or less, or can be in the range of 0.01 mass parts or more and 12 mass parts or less.

[0223] Hereinafter, the details of each step will be described.

[0224] -Dispersion Preparation Steps-

[0225] First, the dispersions used in the cohesive bonding method are prepared. Specifically, a first resin particle dispersion containing first resin particles serving as a binder resin, a colorant dispersion containing a colorant, a second resin particle dispersion containing second resin particles serving as a binder resin, and a release agent particle dispersion containing release agent particles are prepared.

[0226] In addition, in each dispersion preparation step, the first resin particles and the second resin particles are referred to as “resin particles” in the description.

[0227] Here, the resin particle dispersion is prepared by, for example, dispersing the resin particles in a dispersion medium using a surfactant.

[0228] Examples of the dispersion medium used for the resin particle dispersion include aqueous media.

[0229] Examples of the aqueous medium include water such as distilled water and deionized water, and alcohols, etc. These may be used alone or in combination of two or more.

[0230] Examples of surfactants include anionic surfactants such as sulfate esters, 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 can be used in combination with anionic or cationic surfactants.

[0231] The surfactant may be used alone or in combination of two or more.

[0232] In a resin particle dispersion, the resin particles are dispersed in a dispersion medium using, for example, a general dispersion method such as a rotary shearing homogenizer, a ball mill equipped with media, a sand mill, or a dyno-mill. Depending on the type of resin particles, the resin particles may be dispersed in the resin particle dispersion using, for example, a phase inversion emulsification method.

[0233] The phase inversion emulsification method refers to a method in which the resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, a base is added to the organic continuous phase (O phase) for neutralization, and then an aqueous medium (W phase) is added to convert the resin from W / O to O / W (so-called phase inversion) to form a discontinuous phase, thereby dispersing the resin into particles in the aqueous medium.

[0234] The volume average particle size of the resin particles dispersed in the resin particle dispersion is, for example, preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and further preferably 0.1 μm or more and 0.6 μm or less.

[0235] The volume average particle size of the resin particles is determined by dividing the particle size distribution obtained by measurement using a laser diffraction particle size distribution analyzer (e.g., LA-700, manufactured by HORIBA, Ltd.) into the resulting particle size ranges (intervals). A cumulative distribution is plotted starting from the smaller particle size side, and the particle size at which the cumulative distribution of all particles reaches 50% is determined as the volume average particle size D50v. The volume average particle size of particles in other dispersions is also measured in the same manner.

[0236] The content of the resin particles in the resin particle dispersion is, for example, 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.

[0237] In addition, a colorant dispersion and a release agent particle dispersion are prepared in the same manner as the resin particle dispersion. Specifically, the volume average particle size of the particles in the resin particle dispersion, the dispersion medium, the dispersion method, and the particle content are the same for the colorant dispersed in the colorant dispersion and the release agent particles dispersed in the release agent particle dispersion.

[0238] -First Agglomerated Particle Formation Step-

[0239] Next, the first resin particle dispersion, the colorant dispersion, and the release agent particle dispersion are mixed.

[0240] Then, the first resin particles, the colorant, and the release agent particles are heteroaggregated in the mixed dispersion to form first aggregated particles containing the first resin particles, the colorant, and the release agent particles.

[0241] Specifically, for example, a coagulant is added to a dispersion obtained by mixing a first resin particle dispersion, a colorant dispersion, and a release agent particle dispersion, and the pH of the mixed dispersion is adjusted to be acidic (for example, a pH of 2 or more and 5 or less). After adding a dispersion stabilizer as needed, the temperature is set to a range of 20°C or more and 50°C or less, so that the particles dispersed in the mixed dispersion are aggregated to form first aggregated particles.

[0242] In the first condensed particle formation process, for example, the above-mentioned coagulant can be added at room temperature (for example, 25°C) while stirring the mixed dispersion using a rotary shearing homogenizer, and the pH of the mixed dispersion is adjusted to acidic (for example, pH is greater than 2 and less than 5), and the above-mentioned heating is performed after adding a dispersion stabilizer as needed.

[0243] Examples of coagulants include surfactants having a polarity opposite to that of the surfactant used as a dispersant added to the mixed dispersion, inorganic metal salts, and metal complexes having a valence of two or more. In particular, when a metal complex is used as a coagulant, the amount of surfactant used is reduced, and the charging characteristics are improved.

[0244] If necessary, an additive that forms a complex or similar bond with the metal ion of the coagulant may be used. As such an additive, a chelating agent may be used.

[0245] 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.

[0246] As the chelating agent, a water-soluble chelating agent can be used. Examples of the chelating agent include hydroxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid, iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA).

[0247] The amount of the chelating agent added is, for example, preferably 0.01 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass, relative to 100 parts by mass of the first resin particles.

[0248] -Second Agglomerated Particle Formation Step-

[0249] Next, after obtaining a first aggregated particle dispersion in which the first aggregated particles are dispersed, a second resin particle dispersion in which the second resin particles are dispersed is added to the first aggregated particle dispersion.

[0250] In addition, the second resin particles may be of the same kind as the first resin particles or of a different kind.

[0251] Next, in the dispersion of the first agglomerated particles and the second resin particles, the second resin particles are agglomerated on the surfaces of the first agglomerated particles. At this time, a dispersion of release agent particles may be added to agglomerate the second resin particles and the release agent particles on the surfaces of the first agglomerated particles. Specifically, for example, in the first agglomerated particle formation step, when the first agglomerated particles reach a target particle size, a dispersion of second resin particles is added to the first agglomerated particle dispersion, and the mixture is heated below the glass transition temperature of the second resin particles.

[0252] Then, by adjusting the pH of the dispersion liquid to a range of approximately 6.5 or higher and 8.5 or lower, the aggregation is stopped.

[0253] In this manner, second aggregated particles are obtained in which the second resin particles are aggregated so as to adhere to the surfaces of the first aggregated particles.

[0254] -Fusion / unification process-

[0255] Next, the second agglomerated particle dispersion in which the second agglomerated particles are dispersed is heated, for example, to a temperature above the glass transition temperature of the first and second resin particles (for example, a temperature 10 to 30°C higher than the glass transition temperature of the first and second resin particles) to fuse / unify the second agglomerated particles, thereby forming colorant particles.

[0256] Through the above steps, toner particles can be obtained.

[0257] In the above-described aggregation and unification method, the first aggregated particles may be fused and unified to form toner particles without performing the second aggregated particle formation step. Furthermore, the second aggregated particle formation step may be repeated multiple times.

[0258] Here, after the fusion / unification step is completed, the toner particles formed in the solution are subjected to a known washing step, a solid-liquid separation step, and a drying step to obtain dry toner particles.

[0259] The washing step is not particularly limited, but from the perspective of chargeability, it is preferred to fully perform displacement washing with ion-exchanged water. Furthermore, the solid-liquid separation step is not particularly limited, but from the perspective of productivity, suction filtration, pressure filtration, etc. are preferably performed. Furthermore, the drying method is not particularly limited, but from the perspective of productivity, freeze drying, airflow drying, fluidized bed drying, vibrating fluidized bed drying, etc. are preferably performed.

[0260] The toner according to this embodiment is produced, for example, by adding an external additive to the obtained dry toner particles and mixing them. Mixing is preferably performed using, for example, a V-blender, Henschel mixer, or Lödige mixer. Furthermore, if necessary, a vibrating screen or pneumatic screen can be used to remove coarse toner particles.

[0261] <Electrostatic image developer>

[0262] The electrostatic image developer according to this embodiment includes at least the toner according to this embodiment.

[0263] The electrostatic image developer according to the present embodiment may be a one-component developer containing only the toner according to the present embodiment, or a two-component developer in which the toner and a carrier are mixed.

[0264] The carrier is not particularly limited, and known carriers may be used. Examples of the carrier include coated carriers in which a core material composed of magnetic powder is coated with a coating resin; magnetic powder-dispersed carriers in which magnetic powder is dispersed or blended in a matrix resin; and resin-impregnated carriers in which porous magnetic powder is impregnated with a resin.

[0265] Furthermore, the magnetic powder dispersed carrier and the resin impregnated carrier may be a carrier in which the constituent particles of the carrier serve as a core material and the core material is coated with a coating resin.

[0266] Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0267] Examples of the coating resin and matrix resin include styrene-(meth)acrylic resin; polyolefin resins such as polyethylene resin and polypropylene resin; polyvinyl or polyvinylidene resins such as polystyrene, (meth)acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, and polyvinyl ketone; vinyl chloride-vinyl acetate copolymer; linear silicone resin composed of an organic siloxane bond or a modified product thereof; fluororesins such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, and polychlorotrifluoroethylene; polyester; polyurethane; polycarbonate; amino resins such as urea-formaldehyde resin; epoxy resin, etc.

[0268] The coating resin and the matrix resin preferably contain, for example, a (meth)acrylic resin, more preferably contain 50% by mass or more of the (meth)acrylic resin relative to the total mass of the resin, and even more preferably contain 80% by mass or more of the (meth)acrylic resin relative to the total mass of the resin.

[0269] In particular, the coating resin and the matrix resin preferably contain, for example, an alicyclic (meth)acrylic resin as the (meth)acrylic resin.

[0270] Furthermore, the coating resin and the matrix resin may contain other additives such as conductive particles.

[0271] 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.

[0272] Here, in order to coat the surface of the core material with a coating resin, a coating layer forming solution coating method using a coating resin and various additives added as needed dissolved in an appropriate solvent can be cited. The solvent is not particularly limited and can be selected taking into account the coating resin used, coating adaptability, etc.

[0273] Specific resin coating methods include an immersion method in which the core material is immersed in a coating layer forming solution, a spraying method in which the coating layer forming solution is sprayed onto the surface of the core material, a fluidized bed method in which the coating layer forming solution is sprayed while the core material is floating using flowing air, and a kneading coating method in which the core material of the carrier and the coating layer forming solution are mixed in a kneading coater and the solvent is removed.

[0274] The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is, for example, preferably toner:carrier=1:100 to 30:100, and more preferably 3:100 to 20:100.

[0275] <Image Forming Apparatus / Image Forming Method>

[0276] The image forming apparatus and image forming method according to this embodiment will be described.

[0277] The image forming apparatus according to this embodiment includes: an image holder; a charging device for charging the surface of the image holder; an electrostatic image forming device for forming an electrostatic image on the charged surface of the image holder; a developing device for storing an electrostatic image developer and developing the electrostatic image formed on the surface of the image holder into a toner image using the electrostatic image developer; a transfer device for transferring the toner image formed on the surface of the image holder to the surface of a recording medium; and a fixing device for fixing the toner image transferred to the surface of the recording medium. The electrostatic image developer according to this embodiment can be used as the electrostatic image developer.

[0278] In the image forming device involved in this embodiment, an image forming method (the image forming method involved in this embodiment) is implemented, which includes the following processes: a charging process, in which the surface of the image retaining body is charged; an electrostatic image forming process, in which an electrostatic image is formed on the surface of the charged image retaining body; a developing process, in which the electrostatic image formed on the surface of the image retaining body is developed into a toner image using the electrostatic image developer involved in this embodiment; a transfer process, in which the toner image formed on the surface of the image retaining body is transferred to the surface of the recording medium; and a fixing process, in which the toner image transferred to the surface of the recording medium is fixed.

[0279] The image forming device involved in this embodiment can be applicable to the following well-known image forming devices: a device of a direct transfer method in which a toner image formed on the surface of an image retaining body is directly transferred to a recording medium; a device of an intermediate transfer method in which a toner image formed on the surface of an image retaining body is transferred to the surface of an intermediate transfer body for the first time, and the toner image transferred to the surface of the intermediate transfer body is transferred to the surface of a recording medium for a second time; a device having a cleaning device for cleaning the surface of the image retaining body after transferring the toner image but before charging; a device having an electrostatic elimination device for eliminating static electricity by irradiating the surface of the image retaining body with electrostatic elimination light after transferring the toner image and before charging, etc.

[0280] In the case of an intermediate transfer method device, the transfer device can, for example, be applicable to a structure having the following: an intermediate transfer body, on the surface of which a toner image is transferred; a primary transfer device, which transfers the toner image formed on the surface of the image retaining body to the surface of the intermediate transfer body for the primary transfer; and a secondary transfer device, which transfers the toner image transferred to the surface of the intermediate transfer body for the secondary transfer to the surface of the recording medium.

[0281] In addition, in the image forming apparatus involved in this embodiment, for example, the portion including the developing device may be a cartridge structure (processing cartridge) that is detachably mounted on the image forming apparatus. As the processing cartridge, for example, a processing cartridge having a developing device that accommodates the electrostatic image developer involved in this embodiment may be preferably used.

[0282] Hereinafter, an example of the image forming apparatus according to the present embodiment is shown, but the present invention is not limited thereto. In addition, the main parts shown in the drawings will be described, and the description of the other parts will be omitted.

[0283] Figure 1 FIG. 1 is a diagram schematically showing the configuration of an image forming apparatus according to this embodiment.

[0284] Figure 1The image forming apparatus shown includes first to fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K that output images in yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These image forming units (hereinafter sometimes simply referred to as "units") 10Y, 10M, 10C, and 10K are arranged side by side, separated from each other by a predetermined distance in the horizontal direction. Alternatively, these units 10Y, 10M, 10C, and 10K may be process cartridges that are attachable to and detachable from the image forming apparatus.

[0285] An intermediate transfer belt 20, serving as an intermediate transfer member, extends above each unit 10Y, 10M, 10C, and 10K in the drawing. The intermediate transfer belt 20 is wound around a drive roller 22 and a support roller 24, which are arranged to be spaced apart from each other in the left-to-right direction in the drawing, and travels from the first unit 10Y toward the fourth unit 10K. The support roller 24 is biased away from the drive roller 22 by a spring (not shown), thereby applying tension to the intermediate transfer belt 20 wound around the drive roller 22. Furthermore, an intermediate transfer member cleaning device 30 is provided on the outer circumference of the intermediate transfer belt 20, facing the drive roller 22.

[0286] In addition, the toners including the four colors of yellow, magenta, cyan and black contained in the toner cartridges 8Y, 8M, 8C and 8K are supplied to the developing devices (an example of a developing device) 4Y, 4M, 4C and 4K of each unit 10Y, 10M, 10C and 10K respectively.

[0287] The first to fourth units 10Y, 10M, 10C, and 10K have the same structure. Therefore, the first unit 10Y, which forms a yellow image and is located upstream in the direction of travel of the intermediate transfer belt, will be described as a representative unit. Components identical to those of the first unit 10Y will be designated with magenta (M), cyan (C), and black (K) instead of yellow (Y), and the description of the second to fourth units 10M, 10C, and 10K will be omitted.

[0288] The first unit 10Y includes a photoreceptor 1Y, which functions as an image holder. Sequentially arranged around the photoreceptor 1Y are: a charging roller (an example of a charging device) 2Y, which charges the surface of the photoreceptor 1Y to a predetermined potential; an exposure device (an example of an electrostatic image forming device) 3, which exposes the charged surface to a laser beam 3Y based on a color-decomposed image signal to form an electrostatic image; a developing device (an example of a developing device) 4Y, which supplies charged toner to the electrostatic image to develop the electrostatic image; a primary transfer roller (an example of a primary transfer device) 5Y, which transfers the developed toner image to the intermediate transfer belt 20; and a photoreceptor cleaning device (an example of a cleaning device) 6Y, which removes toner remaining on the surface of the photoreceptor 1Y after the primary transfer.

[0289] The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20 and is positioned opposite the photoreceptor 1Y. Furthermore, each of the primary transfer rollers 5Y, 5M, 5C, and 5K is connected to a bias power supply (not shown) for applying a primary transfer bias. Each bias power supply is controlled by a control unit (not shown) to vary the transfer bias applied to each primary transfer roller.

[0290] Next, the operation of forming a yellow image in the first unit 10Y will be described.

[0291] 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.

[0292] The photoreceptor 1Y is conductive (for example, volume resistivity at 20°C: 1×10 -6 The photosensitive layer is formed by laminating a photosensitive layer on a substrate (with a resistance of 100 Ω·cm or less). This photosensitive layer typically has a high electrical resistance (the resistance of a typical resin), but when irradiated with laser beam 3Y, the specific electrical resistance of the portion irradiated by the laser beam changes. Therefore, based on yellow image data sent from a control unit (not shown), laser beam 3Y is output via exposure device 3 to the surface of the charged photoreceptor 1Y. Laser beam 3Y irradiates the photosensitive layer on the surface of photoreceptor 1Y, forming an electrostatic image of a yellow image pattern on the surface of photoreceptor 1Y.

[0293] An electrostatic image refers to an image formed on the surface of the photoreceptor 1Y by charging, and is a so-called negative latent image. It is formed by the resistivity of the irradiated portion of the photosensitive layer being reduced by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y flowing, while on the other hand, the charge on the portion not irradiated by the laser beam 3Y remains.

[0294] The electrostatic image formed on the photoreceptor 1Y rotates to a predetermined development position as the photoreceptor 1Y travels. Then, at the development position, the electrostatic image on the photoreceptor 1Y is visualized (developed) as a toner image by the developing device 4Y.

[0295] The developing device 4Y contains, for example, an electrostatic image developer containing at least yellow toner and a carrier. The yellow toner is triboelectrically charged by being stirred within the developing device 4Y, resulting in a charge of the same polarity (negative) as the charge on the photoreceptor 1Y and being retained on the developer roller (an example of a developer retainer). The surface of the photoreceptor 1Y then passes through the developing device 4Y, whereupon the yellow toner electrostatically adheres to the de-electrostaticized latent image on the surface of the photoreceptor 1Y, thereby developing the latent image with the yellow toner. The photoreceptor 1Y, with the yellow toner image formed on it, continues to travel at a predetermined speed, and the toner image developed on the photoreceptor 1Y is transported to a predetermined primary transfer position.

[0296] When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer roller 5Y. Electrostatic force from the photoreceptor 1Y toward the primary transfer roller 5Y acts on the toner image, transferring the toner image on the photoreceptor 1Y to the intermediate transfer belt 20. The transfer bias applied at this time has a polarity (+) opposite to the polarity (-) of the toner, and is controlled to, for example, +10 μA by a control unit (not shown) in the first unit 10Y.

[0297] On the other hand, the toner remaining on the photoreceptor 1Y is removed and recovered by the photoreceptor cleaning device 6Y.

[0298] Furthermore, the primary transfer bias applied to the primary transfer rollers 5M, 5C, and 5K in and after the second unit 10M is also controlled in accordance with the first unit.

[0299] In this manner, the intermediate transfer belt 20 to which the yellow toner image has been transferred by the first unit 10Y is sequentially transported through the second to fourth units 10M, 10C, and 10K, so that the toner images of the respective colors are superimposed and multi-transferred.

[0300] The intermediate transfer belt 20, to which the four-color toner images have been multiply transferred by the first through fourth units, reaches the secondary transfer section, which is comprised of the intermediate transfer belt 20, a backup roller 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roller (an example of a secondary transfer device) 26 disposed on the outer circumference of the intermediate transfer belt 20. Meanwhile, recording paper (an example of recording medium) P is fed into the gap between the secondary transfer roller 26 and the intermediate transfer belt 20 via a feed mechanism at a predetermined timing, and a secondary transfer bias is applied to the backup roller 24. The applied transfer bias has a (-) polarity, the same as the polarity of the toner (-). Electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, transferring the toner image from the intermediate transfer belt 20 to the recording paper P. The secondary transfer bias is determined based on the resistance detected by a resistance detection device (not shown) that detects the resistance of the secondary transfer section and is voltage-controlled.

[0301] Then, the recording paper P is fed into a pressure-contact portion (nip portion) of a pair of fixing rollers in a fixing device (an example of a fixing device) 28 , where the toner image is fixed on the recording paper P, thereby forming a fixed image.

[0302] Examples of the recording paper P to which the toner image is transferred include plain paper used in electrophotographic copy machines, printers, etc. Examples of the recording medium include OHP paper, etc., in addition to the recording paper P.

[0303] To further improve the smoothness of the image surface after fixing, the surface of the recording paper P is preferably smooth. For example, coated paper obtained by coating the surface of plain paper with a resin or coated paper for printing can be preferably used.

[0304] The recording paper P on which the color image has been fixed is conveyed toward the discharge portion, thereby completing a series of color image forming operations.

[0305] <Process Cartridge / Toner Cartridge>

[0306] The process cartridge according to this embodiment will be described.

[0307] The processing box involved in this embodiment is a processing box equipped with a developing device and is loaded and unloaded from the image forming device. The developing device accommodates the electrostatic image developer involved in this embodiment and uses the electrostatic image developer to develop the electrostatic image formed on the surface of the image holding body into a toner image.

[0308] The process cartridge according to this embodiment is not limited to the above-described structure, and may include a developing device and, if necessary, at least one other device selected from an image holder, a charging device, an electrostatic image forming device, and a transfer device.

[0309] Hereinafter, an example of the process cartridge according to the present embodiment is shown, but the present invention is not limited thereto.

[0310] Figure 2 It is a diagram schematically showing the structure of a process cartridge according to this embodiment.

[0311] Figure 2 The processing box 200 shown is constructed by, for example, integrally combining and holding a photosensitive body 107 (an example of an image holding body), a charging roller 108 (an example of a charging device) provided around the photosensitive body 107, a developing device 111 (an example of a developing device), and a photosensitive body cleaning device 113 (an example of a cleaning device) using a housing 117 having a mounting guide 116 and an opening 118 for exposure, and is made into a box.

[0312] in addition, Figure 2 109 denotes an exposure device (an example of an electrostatic image forming device), 112 denotes a transfer device (an example of a transfer device), 115 denotes a fixing device (an example of a fixing device), and 300 denotes recording paper (an example of a recording medium).

[0313] Next, the toner cartridge according to this embodiment will be described.

[0314] The toner cartridge according to the present embodiment contains the toner according to the present embodiment and is attachable to and detachable from an image forming apparatus. The toner cartridge contains replenishing toner for supplying to a developing device provided in the image forming apparatus.

[0315] in addition, Figure 1 The image forming apparatus shown has a structure in which toner cartridges 8Y, 8M, 8C, and 8K are detachably mounted. The developing devices 4Y, 4M, 4C, and 4K are connected to the toner cartridges corresponding to the respective developing devices (colors) via toner supply tubes (not shown). When the toner contained in a toner cartridge becomes low, the toner cartridge is replaced.

[0316] Example

[0317] Hereinafter, the embodiment of the present invention will be described in detail based on the examples, but the embodiment of the present invention is not limited to these examples. In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0318] Preparation of various dispersions

[0319] (Synthesis of Amorphous Polyester Resin (A))

[0320] Terephthalic acid: 68 parts

[0321] Fumaric acid: 32 parts

[0322] Ethylene glycol: 42 parts

[0323] 1,5-Pentanediol: 47 parts

[0324] The above materials were placed in a flask equipped with a stirrer, a nitrogen inlet tube, a temperature sensor, and a distillation column. The temperature was raised to 220°C over 1 hour under a nitrogen flow, and 1 part of tetraethoxytitanium was added to 100 parts of the above materials. While distilling off the generated water, the temperature was raised to 240°C over 0.5 hours. After a dehydration condensation reaction was continued at 240°C for 1 hour, the reaction product was cooled. This yielded an amorphous polyester resin (A) with a weight-average molecular weight of 97,000 and a glass transition temperature of 60°C.

[0325] (Preparation of Amorphous Polyester Resin Particle Dispersion (A1))

[0326] After placing 40 parts of ethyl acetate and 25 parts of 2-butanol in a container equipped with a temperature regulating member and a nitrogen replacement member to prepare a mixed solvent, 100 parts of amorphous polyester resin (A) were gradually added and dissolved, and a 10% aqueous ammonia solution (equivalent to 3 times the amount of the resin acid value in terms of molar ratio) was added thereto and stirred for 30 minutes. Next, the interior of the container was replaced with dry nitrogen, and the temperature was maintained at 40°C. While stirring the mixed liquid, 400 parts of ion exchange water was added dropwise and emulsified. After the addition was completed, the emulsion was returned to 25°C to obtain a resin particle dispersion in which resin particles with a volume average particle size of 195 nm were dispersed. Ion exchange water was added to the resin particle dispersion, and the solid content was adjusted to 20%, to obtain an amorphous polyester resin particle dispersion (A1) in which particles of the amorphous polyester resin (A) were dispersed.

[0327] (Preparation of Crystalline Polyester Resin Particle Dispersion (B1))

[0328] 1,10-Decanedicarboxylic acid: 260 parts

[0329] 1,6-Hexanediol: 167 parts

[0330] Dibutyltin oxide (catalyst): 0.3 parts

[0331] The above materials were placed in a three-necked flask that had been heated and dried. The air in the flask was replaced with nitrogen to create an inert atmosphere. The mixture was stirred and refluxed at 180°C for 5 hours by mechanical stirring. Subsequently, the temperature was gradually raised to 230°C under reduced pressure and stirred for 2 hours. When the mixture became viscous, it was air-cooled to stop the reaction. In this way, a crystalline polyester resin with a weight-average molecular weight of 12,500 and a melting point of 73°C was obtained. 90 parts of the crystalline polyester resin, 1.8 parts of an anionic surfactant (Tayca Power, manufactured by TAYCA Co., Ltd., 12% solid content, sodium dodecylbenzenesulfonate) and 210 parts of ion-exchanged water were mixed and heated to 120°C. After dispersion using a homogenizer (ULTRA TURRAX T50 manufactured by IKA), the mixture was dispersed using a pressure jet type GAULIN homogenizer for 1 hour to obtain a resin particle dispersion containing resin particles with a volume average particle size of 195 nm. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20%, thereby obtaining a crystalline polyester resin particle dispersion (B1) in which particles of the crystalline polyester resin were dispersed.

[0332] (Preparation of Styrene Acrylic Resin Particle Dispersion (S1))

[0333] Styrene: 375 parts

[0334] n-Butyl acrylate: 25 parts

[0335] Acrylic acid: 2 parts

[0336] Dodecanethiol: 24 parts

[0337] Carbon tetrabromide: 4 parts

[0338] In a flask, the mixture obtained by mixing and dissolving the above materials was dispersed and emulsified in a surfactant solution prepared by dissolving 6 parts of a nonionic surfactant (NONIPOL 400 manufactured by Sanyo Chemical Industries, Ltd.) and 10 parts of an anionic surfactant (Tayca Power, manufactured by TAYCA Co., Ltd., solid content 12%, sodium dodecylbenzenesulfonate) in 550 parts of ion-exchanged water. Subsequently, while stirring the flask, an aqueous solution prepared by dissolving 4 parts of ammonium persulfate in 50 parts of deionized water was added over 20 minutes. Subsequently, after nitrogen substitution, the flask was heated in an oil bath while stirring the contents until it reached 70°C, and emulsion polymerization was continued at 70°C for 5 hours. In this way, a resin particle dispersion in which resin particles having a volume average particle size of 150 nm, a weight average molecular weight (Mw) of 32,000, and a glass transition temperature (Tg) of 57°C were dispersed was obtained. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20%, thereby obtaining a styrene acrylic resin particle dispersion (S1) in which styrene acrylic resin particles were dispersed.

[0339] (Preparation of Colorant Particle Dispersion (Cy1))

[0340] CI Pigment Blue 15:3 (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.): 70 parts

[0341] Anionic surfactant (NEOGEN RK manufactured by DKS Co., Ltd.): 1 part

[0342] Deionized water: 200 parts

[0343] The above materials were mixed and dispersed for 10 minutes using a homogenizer (ULTRA TURRAX T50 manufactured by IKA). Ion-exchanged water was added to obtain a dispersion of colorant particles (Cy1) having a volume average particle size of 190 nm.

[0344] (Preparation of Release Agent Particle Dispersion (W1))

[0345] Ester wax (pentaerythritol behenate wax, manufactured by NOF CORPORATION, trade name WEP5, melting point 76°C): 100 parts

[0346] Anionic surfactant: 1 part

[0347] (Tayca Power, manufactured by TAYCA Co., Ltd., solid content 12%, sodium dodecylbenzenesulfonate)

[0348] Deionized water: 350 parts

[0349] The above materials were mixed and heated to 100°C. After being dispersed using a homogenizer (ULTRA-TURRAX T50 manufactured by IKA), they were dispersed using a pressure jet GAULIN homogenizer to obtain a release agent particle dispersion containing release agent particles having a volume average particle size of 1000 nm. Deionized water was added to this release agent particle dispersion to adjust the solids content to 20%. This was designated as release agent particle dispersion (W1).

[0350] (Preparation of Release Agent Particle Dispersion (W2))

[0351] First, in order to prepare a release agent particle dispersion (W2), the following samples were prepared.

[0352] Polyethylene wax (hydrocarbon wax, POLYWAX (registered trademark) 725 manufactured by Baker Petrolite Corporation, melting point 104°C): 270 parts

[0353] Anionic surfactant (NEOGEN RK manufactured by DKS Co., Ltd.): 13.5 parts

[0354] Deionized water: 21.6 parts

[0355] Next, the three samples were mixed and polyethylene wax (POLYWAX 725) was dissolved using a pressure jet homogenizer (Gorin Homogenizer, manufactured by Gorin Co., Ltd.). The polyethylene wax (POLYWAX 725) was dispersed at a pressure of 5 MPa for 120 minutes, followed by a dispersion at 40 MPa for 360 minutes to obtain a mixed solution. The resulting mixed solution was cooled, and ion-exchanged water was added to obtain a release agent particle dispersion (W2) adjusted to a solids concentration of 20.0%.

[0356] The volume average particle size of the particles in the obtained release agent particle dispersion (W2) was 225 nm.

[0357] <Toner Production>

[0358] (Preparation of Toner 1)

[0359] - Agglomerated particle formation process-

[0360] Deionized water: 200 parts

[0361] Colorant particle dispersion (Cy1): 15 parts

[0362] Release agent particle dispersion (W1): 10.0 parts

[0363] Styrene acrylic resin particle dispersion (S1): 107 parts

[0364] Amorphous polyester resin particle dispersion (A1): 100 parts

[0365] Crystalline polyester resin particle dispersion (B1): 10 parts

[0366] Anionic surfactant (Tayca Power, manufactured by TAYCA Co., Ltd., solid content 12%, sodium dodecylbenzenesulfonate): 0.25 parts

[0367] The above materials were placed in a round stainless steel flask, 0.1N (0.1 mol / L) nitric acid was added, and the pH was adjusted to 3.5. Then, an aqueous solution of magnesium chloride (6 parts of magnesium chloride dissolved in 30 parts of ion-exchanged water) and an aqueous solution of decyltrimethylammonium bromide (5.5 parts of decyltrimethylammonium bromide dissolved in 60 parts of ion-exchanged water) were added. After dispersion at 30°C using a homogenizer (ULTRA TURRAX T50 manufactured by IKA), heating was started. While successively confirming the agglomerated particle size, the mixture was heated to 45°C in a heating oil bath and maintained until the volume average particle size reached 4.9 μm, thereby obtaining first agglomerated particles (first agglomerated particle formation step).

[0368] To the dispersion containing the first aggregated particles prepared as described above, 38 parts of a styrene acrylic resin particle dispersion (S1) and 35 parts of an amorphous polyester resin particle dispersion (A1) as the shell component were slowly added. The temperature of the heating jacket was further increased and maintained at 50°C for 1 hour. 0.04 parts of ozone water (3 ppm, manufactured by Ozone Buster Industry, manufactured by Earthwalker Trading Co., Ltd.) was added to obtain second aggregated particles. The volume average particle diameter of the obtained second aggregated particles was measured to be 5.4 μm (second aggregated particle formation step).

[0369] Then, while continuing stirring, 20 parts of 10% EDTA (ethylenediaminetetraacetic acid) was added, and then the pH was adjusted to 9.0 using a 1N sodium hydroxide aqueous solution to stop the aggregation.

[0370] -Fusion / unification process-

[0371] Next, while continuing to stir, the temperature was raised to 85°C at a heating rate of 0.05°C / min, maintained at 85°C for 3 hours, and then cooled to 30°C at a rate of 15°C / min (first cooling). Next, the temperature was raised to 85°C at a heating rate of 0.2°C / min (reheating), maintained for 30 minutes, and then cooled to 30°C at a rate of 0.5°C / min (second cooling).

[0372] Next, the solid content was filtered out, washed three times with 500 mL of ion-exchanged water, and dried to obtain toner particles 1 having a volume average particle size of 5.2 μm.

[0373] -Addition of external additives-

[0374] 100 parts of Toner Particles 1 and 1.5 parts of hydrophobic silica (RY50, manufactured by NIPPON AEROSIL CO., LTD.) were mixed and mixed for 30 seconds at 10,000 rpm using a sample mill. The mixture was sieved with a vibrating sieve having an aperture of 45 μm to obtain Toner 1.

[0375] (Production of Toners 2 to 18 and Toners C1 to C4)

[0376] Toners 2 to 18 and Toners C1 to C4 were obtained in the same manner as Toner 1, except that the amounts of the styrene acrylic resin particle dispersion (S1) (“StAc” in the table), the amorphous polyester resin particle dispersion (A1) (“amorphous PES” in the table), the crystalline polyester resin particle dispersion (B1) (“crystalline PES” in the table), the release agent particle dispersion (W1) (“ester wax” in the table), the release agent particle dispersion (W2) (“paraffin wax” in the table), the anionic surfactant (sodium dodecylbenzenesulfonate) (“sulfur-containing solution” in the table), decyltrimethylammonium bromide (“bromine-containing compound” in the table), and ozone water used in the aggregated particle formation step were set as shown in Table 1.

[0377] The amounts of the styrene acrylic resin particle dispersion (S1) and the amorphous polyester resin particle dispersion (A1) listed in Table 1 are the total amounts added in the first aggregated particle forming step and the second aggregated particle forming step. 74% of the total amount was used in the first aggregated particle forming step, and 26% of the total amount was used in the second aggregated particle forming step, thereby producing second aggregated particles.

[0378] <Measurement and Evaluation of Toner>

[0379] (Measurement of Toner)

[0380] For the obtained toner, IBr, IS, and IO were determined by the above-described method, and the results are shown in Tables 2 and 3. Furthermore, IS / IBr and IBr / IO were calculated, and the results are shown in Tables 2 and 3.

[0381] (Production of Developer)

[0382] -Preparation of vector (CA)-

[0383] After stirring 500 parts of spherical magnetite powder particles (volume average particle size 0.55 μm) in a Henschel mixer, 5 parts of a titanate coupling agent were added, the temperature was raised to 100°C, and stirring was continued for 30 minutes. Next, 6.25 parts of phenol, 9.25 parts of 35% formalin, 500 parts of magnetite particles treated with a titanate coupling agent, 6.25 parts of 25% ammonia water, and 425 parts of water were placed in a four-necked flask and stirred. The mixture was reacted at 85°C for 120 minutes while stirring. The mixture was then cooled to 25°C, 500 parts of water was added, the supernatant was removed, and the precipitate was washed with water. The washed precipitate was heated and dried under reduced pressure to obtain a carrier (CA) with an average particle size of 35 μm.

[0384] -Production of developer-

[0385] Each toner and a carrier (CA) were placed in a V-type blender at a mass ratio (toner / carrier) of 5 / 95, and stirred for 20 minutes to obtain each developer.

[0386] (Evaluation of Color Developing Properties of Toner)

[0387] The color development property of the toner was evaluated by determining the chroma of a color image as a cyan solid image. The output chart for the evaluation used an image sample of the Electrophotographic Society Test Chart No. 5-1.

[0388] Continuously form 100 sheets and adjust the toner load to 4.5 g / m 2 Color images were taken from each of the 10 images, and the CIE1976L was calculated for each of the 10 locations in the periphery (10 mm from the end) and the interior of each image using an X-Rite939 (pore diameter 4 mm) manufactured by X-Rite Inc. * a * b * The coordinate value of the color system (L * value, a * Value and b * values), and the chroma (C * ). About the chroma of color image (C * ), and evaluated according to the following evaluation criteria. The results are shown in Tables 2 and 3.

[0389] Formula: C * =((a * ) 2 +(b * ) 2 ) 1 / 2

[0390] - Chroma (C * )'s evaluation criteria -

[0391] A: 62≤C * (The saturation of color images is not impaired and appears well)

[0392] A-:58≤C * <62 (The saturation of the color image is not impaired and appears well)

[0393] B: 54≤C * <58 (color image saturation is not hindered and appears)

[0394] B-:50≤C * <54 (the saturation of color images is not hindered and appears)

[0395] C:C * <50 (the saturation of color images is hindered and reduced)

[0396]

[0397] [Table 2]

[0398]

[0399] [Table 3]

[0400]

[0401] The above results show that, in this embodiment, the saturation of the color image is higher than that of the comparative example, and the color development property of the toner is better.

[0402] This embodiment includes the following aspects. (1)

[0404] A toner for developing electrostatic images, comprising toner particles containing a resin and a colorant,

[0405] When the Net intensity of the Br element in the toner particles measured by fluorescent X-ray analysis is defined as Ibr and the Net intensity of the S element measured by fluorescent X-ray analysis is defined as IS,

[0406] Ibr is 1kcps or more and 30kcps or less, and

[0407] IS / Ibr is 0.005 or more and 1.2 or less. (2)

[0409] The electrostatic image developing toner according to (1), wherein

[0410] When the Net intensity of the O element in the toner particles measured by fluorescent X-ray analysis is defined as IO, IBr / IO is 4.76 or more and 333 or less. (3)

[0412] The electrostatic image developing toner according to (1) or (2), wherein

[0413] IBr is 10 kcps or more and 25 kcps or less. (4)

[0415] The electrostatic image developing toner according to (3), wherein

[0416] IS / IBr is 0.03 or more and 0.06 or less. (5)

[0418] The electrostatic image developing toner according to any one of (2) to (4), wherein

[0419] IBr / IO is 83.3 or more and 143 or less. (6)

[0421] The electrostatic image developing toner according to any one of (1) to (5), wherein

[0422] The resin includes a polyester resin. (7)

[0424] The electrostatic image developing toner according to any one of (1) to (6), wherein

[0425] The toner particles contain a releasing agent comprising an ester wax. (8)

[0427] An electrostatic image developer comprising the electrostatic image developing toner according to any one of (1) to (7). (9)

[0429] A toner cartridge containing the electrostatic image developing toner described in any one of (1) to (7),

[0430] The image forming apparatus is mounted and removed from the image forming apparatus. (10)

[0432] A process cartridge comprising a developing device that accommodates the electrostatic image developer described in (8) and develops an electrostatic image formed on a surface of an image holding member into a toner image using the electrostatic image developer.

[0433] The process cartridge is attachable to and detachable from the image forming apparatus. (11)

[0435] An image forming apparatus comprising:

[0436] Image holding body;

[0437] a charging device for charging the surface of the image holding member;

[0438] an electrostatic image forming device for forming an electrostatic image on the charged surface of the image holding member;

[0439] a developing device that accommodates the electrostatic image developer described in (8) and develops the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer;

[0440] a transfer device that transfers the toner image formed on the surface of the image holding member to the surface of a recording medium; and

[0441] The fixing device fixes the toner image transferred onto the surface of the recording medium. (12)

[0443] An image forming method comprising:

[0444] a charging process for charging the surface of the image holding member;

[0445] an electrostatic image forming step of forming an electrostatic image on the charged surface of the image holding member;

[0446] a developing step of developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer described in (8);

[0447] a transfer step of transferring the toner image formed on the surface of the image holding member to the surface of a recording medium; and

[0448] The fixing step fixes the toner image transferred onto the surface of the recording medium.

[0449] According to the invention of (1), there is provided a toner for developing electrostatic images having better color development properties than when the IBr is less than 1 kcps or exceeds 30 kcps or the IS / IBr is less than 0.005 or exceeds 1.2.

[0450] According to the invention according to (2), there is provided a toner for developing electrostatic images having better color development properties than when IBr / IO is less than 4.76 or exceeds 333.

[0451] According to the invention according to (3), there is provided a toner for developing electrostatic images having better color development properties than a toner having an IBr of less than 10 kcps or exceeding 25 kcps.

[0452] According to the invention according to (4), there is provided a toner for developing an electrostatic image having better color development properties than when IS / IBr is less than 0.03 or exceeds 0.06.

[0453] According to the invention according to (5), there is provided a toner for developing electrostatic images having better color development properties than when IBr / IO is less than 83.3 or exceeds 143.

[0454] According to the invention according to (6), there is provided a toner for developing an electrostatic image having better color development properties than a toner in which the resin is composed of a styrene acrylic resin.

[0455] According to the invention according to (7), there is provided a toner for developing electrostatic images having better color development properties than a toner containing a release agent composed of paraffin wax.

[0456] According to the invention involved in (8), (9), (10), (11) or (12), the following electrostatic image developer, toner box, processing box, image forming device or image forming method is provided, which can easily obtain an image with high saturation compared with the case where a toner for electrostatic image development with an IBr of less than 1 kcps or exceeding 30 kcps or an IS / IBr of less than 0.005 or exceeding 1.2 is used.

[0457] The above-described embodiments of the present invention are provided for the purpose of illustration and explanation. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed embodiments. It is obvious that various modifications and variations are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily explain the principles of the present invention and its application. Thus, other technical personnel in this field can understand the present invention through various modifications optimized for specific uses of the assumed various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

Claims

1. A toner for developing electrostatic images, comprising toner particles containing a resin and a colorant, When the Net intensity of the Br element in the toner particles measured by fluorescent X-ray analysis is defined as Ibr and the Net intensity of the S element measured by fluorescent X-ray analysis is defined as IS, Ibr is 1kcps or more and 30kcps or less, and IS / Ibr is 0.005 or more and 1.2 or less.

2. The electrostatic image developing toner according to claim 1, wherein When the Net intensity of the O element in the toner particles measured by fluorescent X-ray analysis is defined as IO, IBr / IO is 4.76 or more and 333 or less.

3. The electrostatic image developing toner according to claim 1 or 2, wherein IBr is 10 kcps or more and 25 kcps or less.

4. The electrostatic image developing toner according to claim 3, wherein IS / IBr is 0.03 or more and 0.06 or less. 5 . The electrostatic image developing toner according to claim 2 , wherein IBr / IO is 83.3 or more and 143 or less. 6 . The electrostatic image developing toner according to claim 1 , wherein: The resin includes a polyester resin. 7 . The electrostatic image developing toner according to claim 1 , wherein: The toner particles contain a releasing agent comprising an ester wax. 8 . An electrostatic image developer comprising the electrostatic image developing toner according to claim 1 .

9. A toner cartridge containing the electrostatic image developing toner according to any one of claims 1 to 7, The image forming apparatus is mounted and removed from the image forming apparatus.

10. A process cartridge comprising a developing device, the developing device housing the electrostatic image developer according to claim 8 and developing an electrostatic image formed on a surface of an image holding member into a toner image using the electrostatic image developer, The process cartridge is attachable to and detachable from the image forming apparatus.

11. An image forming apparatus comprising: Image holding body; a charging device for charging the surface of the image holding member; an electrostatic image forming device for forming an electrostatic image on the charged surface of the image holding member; a developing device that accommodates the electrostatic image developer according to claim 8 and develops the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer; a transfer device for transferring the toner image formed on the surface of the image holding member to the surface of a recording medium; and The fixing device fixes the toner image transferred onto the surface of the recording medium.

12. An image forming method comprising: a charging process for charging the surface of the image holding member; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image holding member; a developing step of developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer according to claim 8; a transfer step of transferring the toner image formed on the surface of the image holding member to the surface of a recording medium; and The fixing step fixes the toner image transferred onto the surface of the recording medium.

Images